阅读说明：本技术 含氟树脂薄膜和层叠体以及热压层叠体的制造方法 (Fluorine-containing resin film, laminate, and method for producing hot-pressed laminate ) 是由 细田朋也 寺田达也 山边敦美 木寺信隆 笠井涉 于 2018-05-17 设计创作，主要内容包括：本发明的目的在于,提供耐热性优异并且与预浸料等层叠对象物的层间粘附性优异的含氟树脂薄膜或含氟树脂层叠体、使用该薄膜或层叠体的热压层叠体的制造方法、以及印刷电路板的制造方法。一种含氟树脂薄膜,其包含熔点为260℃～380℃的含氟树脂,并且利用原子力显微镜测定所述含氟树脂薄膜的厚度方向的至少一个表面的1μm<Sup>2</Sup>内时的算术平均粗糙度Ra为3.0nm以上。一种层叠体1,其具有包含所述含氟树脂的层A10和由其它基材形成的层B12,并且利用原子力显微镜测定层A10的第二表面10b的1μm<Sup>2</Sup>内时的算术平均粗糙度Ra为3.0nm以上。(An object of the present invention is to provide a fluororesin film or a fluororesin laminate excellent in heat resistance and excellent in interlayer adhesion to a lamination object such as a prepreg, a method for producing a hot-pressed laminate using the film or the laminate, and a method for producing a printed wiring board. A fluorine-containing resin film comprising a fluorine-containing resin having a melting point of 260 to 380 ℃, wherein 1 [ mu ] m of at least one surface in the thickness direction of the fluorine-containing resin film is measured by an atomic force microscope 2 The arithmetic average roughness Ra in the inner range is 3.0nm or more. A laminate 1 having a layer A10 comprising the fluorine-containing resin and a layer B12 formed from another base material, and 1 μm of the second surface 10B of the layer A10 was measured with an atomic force microscope 2 The arithmetic average roughness Ra in the inner range is 3.0nm or more.)

1. A fluorine-containing resin film comprising a fluorine-containing resin having a melting point of 260 to 380 ℃, wherein 1 [ mu ] m of at least one surface in the thickness direction of the fluorine-containing resin film is measured by an atomic force microscope²The arithmetic average roughness Ra in the inner range is 3.0nm or more.

2. A laminate comprising a layer A and a layer B, wherein the layer A comprises a material containing a fluorine-containing resin having a melting point of 260 to 380 ℃, the layer B comprises a material not containing the fluorine-containing resin, and at least one surface of the laminate is constituted by the surface of the layer A,

at least one surface of the surface of layer A of the laminate is 1 μm as measured by an atomic force microscope²A surface having an arithmetic average roughness Ra of 3.0nm or more.

3. The laminate according to claim 2, wherein,

the fluorine-containing resin has a melt viscosity of 1 x 10 at 380 ℃²Pa·s～1×10⁶Pa · s tetrafluoroethylene polymer.

4. The laminate according to claim 2 or 3,

determination of 1 μm in the surface by means of atomic force microscopy²The maximum height Rz at internal time is 80.0nm or more.

5. The laminate according to any one of claims 2 to 4,

the composition ratio of oxygen atoms to the total of three elements of carbon atoms, fluorine atoms and oxygen atoms in the surface is 1% or more.

6. The laminate according to any one of claims 2 to 5, wherein,

the composition ratio of fluorine atoms in the surface to the total of three elements of carbon atoms, fluorine atoms and oxygen atoms is 25% to 65%.

7. The laminate according to any one of claims 2 to 6,

the layer B is a metal base material layer.

8. The laminate according to claim 7, wherein,

the metal substrate layer is a copper foil layer, and the thickness of the copper foil is determined according to JIS C6515: 1998(IEC 61249-5-1: 1995), the maximum height Rz of the surface roughness is 1nm or more and 2.5 μm or less.

9. The laminate according to any one of claims 2 to 8,

the laminate is a laminate which is laminated on an object to be laminated by hot pressing with the surface of the layer a as a lamination surface.

10. The laminate according to claim 9, wherein,

the object to be laminated is a prepreg.

11. The laminate according to claim 10, wherein,

the object to be adhered is a prepreg comprising a thermosetting resin as a matrix resin, and the curing temperature of the thermosetting resin is not higher than the melting point of the fluorine-containing resin.

12. The laminate according to claim 11, wherein,

the matrix resin is at least one selected from the group consisting of epoxy resin, polyphenylene oxide, polyphenylene ether, and polybutadiene.

13. A laminate having a layer A comprising a material containing a fluorine-containing resin having a melting point of 260 to 380 ℃ and a layer B comprising a material not containing the fluorine-containing resin, wherein,

the layer B has a structure in which the layer A and the layer B are directly laminated, the peel strength at the interface between the directly laminated layer A and layer B is 5N/10mm or more, and the relative dielectric constant (20GHz) of the laminate is less than 3.6.

14. The laminate according to claim 13, wherein,

the composition ratio of oxygen atoms is 1% or more and the composition ratio of fluorine atoms is 25% or more and 65% or less with respect to the total of three elements of carbon atoms, fluorine atoms and oxygen atoms in the surface of the layer a in contact with the layer B.

15. A method for producing a hot-pressed laminate, wherein,

laminating an object to be laminated on a surface of the fluorine-containing resin film according to claim 1 or the laminate according to any one of claims 2 to 14, the surface having an arithmetic average roughness Ra of 3.0nm or more by hot pressing.

16. The method for producing a hot-pressed laminate according to claim 15, wherein,

hot pressing is performed at a temperature not higher than the melting point of the fluorine-containing resin.

17. A method for producing a hot-pressed laminate, wherein,

a fluororesin thin film containing a fluororesin having a melting point of 260 to 380 ℃ is subjected to surface treatment to obtain a fluororesin thin film having a wetting tension of at least one surface in the thickness direction of 30mN/m or more, and an object to be laminated is laminated on the surface of the obtained fluororesin thin film having a wetting tension of 30mN/m or more by hot pressing at a temperature of the melting point of the fluororesin or less.

18. The method for producing a hot-pressed laminate according to any one of claims 15 to 17,

the object to be laminated is a prepreg, a glass member, or a ceramic member.

19. The method for producing a hot-pressed laminate according to claim 18, wherein,

the object to be adhered is a prepreg.

20. The method for producing a hot-pressed laminate according to claim 19, wherein,

the matrix resin of the prepreg is at least one selected from the group consisting of epoxy resin, polyphenylene oxide, polyphenylene ether, and polybutadiene.

21. A method for manufacturing a printed circuit board, wherein,

a printed wiring board obtained by manufacturing a hot-pressed laminate wherein the layer B is a metal layer by the method for manufacturing a hot-pressed laminate according to any one of claims 15 to 20, and etching the metal layer to form a pattern circuit.

Technical Field

The present invention relates to a fluororesin film, a laminate, and a method for producing a hot-pressed laminate.

Background

In recent years, with the weight reduction, size reduction, and density increase of electronic products, the demand for various printed wiring boards has been increasing. As a printed wiring board, for example, a printed wiring board in which a circuit is formed by laminating a substrate containing an insulating material and a metal foil and patterning the metal foil is used. An insulating material for a printed circuit board is required to have excellent electrical characteristics (such as a low dielectric constant) that can cope with frequencies in a high frequency band, excellent heat resistance that can withstand reflow soldering, and the like.

As an insulating material having a low dielectric constant and useful for printed wiring boards, a fluorine-containing resin has been proposed. For example, a laminate comprising a layer containing a cured product of a fluororesin having a functional group such as a carbonyl group and having a melting point of 260 to 320 ℃ and a thermosetting resin and a metal foil has been proposed for use in a printed wiring board (patent document 1).

Disclosure of Invention

Problems to be solved by the invention

In a printed wiring board, for example, a lamination object such as a prepreg may be laminated on a side of a layer containing a fluorine-containing resin opposite to a metal foil by hot pressing. When a fluororesin having a melting point of 260 to 320 ℃ is used, excellent heat resistance can be obtained. However, when a fluororesin having a high melting point of 260 to 320 ℃ is used, the heat-resistant temperature of a cured product of a prepreg or the like is generally lower than the melting point of the fluororesin. Therefore, the hot pressing needs to be performed at a temperature close to the heat-resistant temperature lower than the melting point of the fluororesin, and the fluororesin is not sufficiently melted, and it is difficult to obtain sufficient adhesion.

An object of the present invention is to provide a fluororesin film having excellent heat resistance and excellent interlayer adhesion to an object to be laminated such as a prepreg when laminated by hot pressing, and a laminate having a fluororesin layer. Further, another object of the present invention is to provide a method for producing a hot-pressed laminate and a method for producing a printed wiring board using the fluorine-containing resin film and the laminate.

Means for solving the problems

The present invention has the following aspects.

[1]A fluorine-containing resin film comprising a fluorine-containing resin having a melting point of 260 to 380 ℃, wherein 1 [ mu ] m of at least one surface in the thickness direction of the fluorine-containing resin film is measured by an atomic force microscope²The arithmetic average roughness Ra in the inner range is 3.0nm or more.

[2]A laminate comprising a layer A and a layer B, wherein the layer A comprises a material containing a fluororesin having a melting point of 260 to 380 ℃, the layer B comprises a material not containing the fluororesin, at least one surface of the laminate is constituted by the surface of the layer A, and at least one surface of the layer A of the laminate is 1 [ mu ] m as measured by an atomic force microscope²A surface having an arithmetic average roughness Ra of 3.0nm or more.

[3]Such as [2]]The laminate according to (1), wherein the fluorine-containing resin has a melt viscosity of 1X 10 at 380 ℃²Pa·s～1×10⁶Pa · s tetrafluoroethylene polymer.

[4]Such as [2]]Or [ 3]]The laminate according to (1), wherein the thickness of the surface is 1 μm as measured by an atomic force microscope²The maximum height Rz at internal time is 80.0nm or more.

[5] The laminate according to any one of [2] to [4], wherein a composition ratio of an oxygen atom to a total of three elements of a carbon atom, a fluorine atom, and an oxygen atom in the surface is 1% or more.

[6] The laminate according to any one of [2] to [5], wherein a composition ratio of fluorine atoms to a total of three elements of carbon atoms, fluorine atoms, and oxygen atoms in the surface is 25% or more and 65% or less.

[7] The laminate according to any one of [2] to [6], wherein the layer B is a metal base material layer.

[8] The laminate according to [7], wherein the metal base material layer is a copper foil layer, and the metal base material layer is a laminate based on JISC 6515: 1998(IEC 61249-5-1: 1995), the maximum height Rz of the surface roughness is 1nm or more and 2.5 μm or less.

[9] The laminate according to any one of [2] to [8], wherein the laminate is a laminate which is laminated on an object to be laminated by hot pressing with a surface of the layer A as a lamination surface.

[10] The laminate according to [9], wherein the object to be laminated is a prepreg.

[11] The laminate according to [10], wherein the object to be adhered is a prepreg comprising a thermosetting resin as a matrix resin, and the curing temperature of the thermosetting resin is not higher than the melting point of the fluororesin.

[12] The laminate according to [11], wherein the matrix resin is at least one selected from the group consisting of an epoxy resin, a polyphenylene oxide, a polyphenylene ether and a polybutadiene.

[13] A laminate having a layer A comprising a material containing a fluorine-containing resin having a melting point of 260 to 380 ℃ and a layer B comprising a material not containing the fluorine-containing resin, wherein,

the layer B has a structure in which the layer A and the layer B are directly laminated, the peel strength at the interface between the directly laminated layer A and layer B is 5N/10mm or more, and the relative dielectric constant (20GHz) of the laminate is less than 3.6.

[14] The laminate according to [13], wherein a composition ratio of oxygen atoms with respect to a total of three elements of a carbon atom, a fluorine atom and an oxygen atom in a surface of the layer A in contact with the layer B is 1% or more and a composition ratio of fluorine atoms is 25% or more and 65% or less.

[15] A method for producing a hot-pressed laminate, wherein a laminate to be laminated is laminated on the surface of the fluorine-containing resin thin film of [1] or the laminate of any one of [2] to [14] having an arithmetic average roughness Ra of 3.0nm or more by hot pressing.

[16] The method for producing a hot-pressed laminate according to [15], wherein,

hot pressing is performed at a temperature not higher than the melting point of the fluorine-containing resin.

[17] A method for producing a hot-pressed laminate, wherein a fluorine-containing resin film containing a fluorine-containing resin having a melting point of 260 to 380 ℃ is subjected to surface treatment to obtain a fluorine-containing resin film having a wetting tension of 30mN/m or more on at least one surface in the thickness direction, and an object to be laminated is laminated on the surface of the obtained fluorine-containing resin film having a wetting tension of 30mN/m or more by hot pressing at a temperature of not more than the melting point of the fluorine-containing resin.

[18] The method for producing a hot-pressed laminate according to any one of [15] to [17], wherein the object to be laminated is a prepreg, a glass member, or a ceramic member.

[19] The method for producing a hot-pressed laminate according to [18], wherein the object to be adhered is a prepreg.

[20] The method for producing a hot-pressed laminate according to [19], wherein the matrix resin of the prepreg is at least one selected from the group consisting of an epoxy resin, a polyphenylene oxide, a polyphenylene ether, and a polybutadiene.

[21] A method for manufacturing a printed wiring board, wherein a hot-pressed laminate in which the layer B is a metal layer is manufactured by the method for manufacturing a hot-pressed laminate according to any one of the above [15] to [20], and a pattern circuit is formed by etching the metal layer, thereby obtaining a printed wiring board.

Effects of the invention

According to the present invention, a fluororesin film and a laminate having a fluororesin layer, which have excellent heat resistance and excellent adhesion to a lamination target such as a prepreg when laminated by hot pressing, can be provided. Further, a method for producing a hot-pressed laminate and a method for producing a printed wiring board using the fluorine-containing resin film and the laminate can be provided.

Drawings

Fig. 1 is a cross-sectional view showing an example of the laminate of the present invention.

Fig. 2 is a cross-sectional view showing another example of the laminate of the present invention.

Fig. 3 is a graph showing the transmission loss measurement results of example 13 and comparative example 2.

Fig. 4 is a graph showing the transmission loss measurement results of example 14 and comparative example 3.

Fig. 5 is a graph showing the transmission loss measurement results of example 15 and comparative example 4.

Fig. 6 is a graph showing the transmission loss measurement results of example 21 and comparative example 5.

Fig. 7 is a graph showing the transmission loss measurement results of example 22 and comparative example 6.

Detailed Description

The following terms have the following meanings.

The arithmetic average roughness Ra and the maximum height Rz of the sample were measured by an Atomic Force Microscope (AFM), and the average roughness Ra and the maximum height Rz were measured at 1 μm by an AFM manufactured by Oxford instruments²Ra and Rz of the surface of the range. The measurement conditions are as follows.

And (3) probe: AC160TS-C3 (front end R < 7nm, spring constant 26N/m), measurement mode: AC-Air, scanning rate: 1 Hz.

Hereinafter, the measurement of 1 μm by AFM²Ra and Rz of the surface of the range are denoted Ra (AFM) and Rz (AFM), respectively.

In the present specification, the case where only the "maximum height Rz" is described means "based on JIS C6515: 1998(IEC 61249-5-1: 1995) maximum height Rz' of the surface roughness.

The "melting point" refers to a temperature corresponding to the maximum value of a melting peak measured by Differential Scanning Calorimetry (DSC).

"capable of melt molding" means exhibiting melt fluidity.

"exhibiting melt fluidity" means that there is a temperature at which the melt flow rate reaches 0.1g/10 min to 1000g/10 min in a temperature range of 20 ℃ or more higher than the melting point of the resin under a load of 49N.

"melt flow rate" means JIS K7210: the melt Mass Flow Rate (MFR) specified in 1999(ISO 1133: 1997).

The "relative dielectric constant" is a value determined at 1MHz using a dielectric breakdown tester (YSY-243-100RHO (manufactured by YAMAYO tester)) under a test environment in which the temperature is maintained in the range of 23 ℃. + -. 2 ℃ and the relative humidity is maintained in the range of 50%. + -. 5% RH by the variable bridge method according to ASTM D150. The relative dielectric constant in a high frequency band is a value measured at a frequency of 20GHz in an environment of 23 ℃. + -. 2 ℃ and 50%. + -. 5% RH by the SPDR (split dielectric resonator) method. Hereinafter, the relative permittivity measured at 1MHz is referred to as "relative permittivity (1 MHz)", and the relative permittivity measured at 20GHz is referred to as "relative permittivity (20 GHz)".

"Unit" of a polymer refers to the portion of the polymer derived from a molecule of the monomer formed by polymerization of the monomer. The unit may be a polymer portion directly formed by polymerization of a monomer, or may be a polymer portion obtained by treating a polymer to convert a part of the polymer portion into another structure.

"monomer" means a compound having a polymerizable unsaturated bond such as a polymerizable double bond.

The "acid anhydride group" means a group represented by — C (═ O) -O — C (═ O) -.

"(meth) acrylate" means either acrylate or methacrylate.

[ fluorine-containing resin film ]

The fluorine-containing resin thin film of the present invention comprises a fluorine-containing resin having a melting point of 260 to 380 ℃ and has an Ra (AFM) of 3.0nm or more on at least one surface in the thickness direction. The fluororesin film of the present invention is particularly effective as a film laminated on an object to be laminated by hot pressing.

Hereinafter, the fluororesin having a melting point of 260 to 380 ℃ will be referred to as "fluororesin F".

The melting point of the fluorine-containing resin F is 260-380 ℃. The fluorine-containing resin F has excellent heat resistance when the melting point is 260 ℃ or higher. The fluorine-containing resin F has excellent moldability if the melting point thereof is 380 ℃ or lower.

The melting point of the fluorine-containing resin F can be adjusted by the kind, content ratio, molecular weight, and the like of the unit constituting the polymer of the fluorine-containing resin F.

The melt flow rate of the fluorine-containing resin F is preferably from 0.1g/10 min to 1000g/10 min, more preferably from 0.5g/10 min to 100g/10 min, still more preferably from 1g/10 min to 30g/10 min, particularly preferably from 5g/10 min to 20g/10 min. If the melt flow rate is not less than the lower limit of the above range, the fluorine-containing resin F is excellent in moldability. If the melt flow rate is not more than the upper limit of the above range, the mechanical strength of the fluorine-containing resin film becomes high.

The fluorine-containing resin F has a relative dielectric constant (1MHz) of preferably 2.5 or less, more preferably 2.4 or less, and particularly preferably 2.0 to 2.4. The lower the relative dielectric constant of the fluorine-containing resin F, the more excellent the electrical characteristics of the fluorine-containing resin film, and excellent transmission efficiency can be obtained when the fluorine-containing resin film is used for a substrate of a printed wiring board. The relative dielectric constant of the fluorine-containing resin F can be adjusted by the content of unit u1 described later.

The fluorine-containing resin F preferably has a melt viscosity of 1X 10 at 380 ℃²Pa·s～1×10⁶And a tetrafluoroethylene polymer of Pa · s (hereinafter, also referred to as TFE polymer). The melt viscosity of the fluorine-containing resin F can be measured by holding a sample 2g heated at a measurement temperature for 5 minutes in advance under a load of 0.7MPa by a flow tester and a 2. phi. -8L die in accordance with ASTM D1238.

The TFE polymer preferably has a melt viscosity of 1X 10 at 340 DEG C²Pa·s～1×10⁶Pa · s, particularly preferably a melt viscosity at 300 ℃ of 1X 10²Pa·s～1×10⁶Pa·s。

The TFE-based polymer is a polymer including a unit (hereinafter, also referred to as "unit u 1") derived from tetrafluoroethylene (hereinafter, referred to as TFE). The TFE-based polymer may be a homopolymer of TFE, or a copolymer of TFE and a monomer copolymerizable with TFE (hereinafter, also referred to as a comonomer). The TFE-based polymer preferably contains the unit u1 in an amount of 90 mol% or more based on the total units contained in the polymer.

Examples of the TFE-based polymer include low-molecular-weight polytetrafluoroethylene (hereinafter, also referred to as PTFE) described later and a fluoropolymer F described later.

The low molecular weight PTFE may have a melt viscosity of 1X 10 at 380 ℃ of the whole polymer²Pa·s～1×10⁶The PTFE of Pa · s may be PTFE in which only the shell portion satisfies the above melt viscosity in a core-shell structure including a core portion and a shell portion.

The low molecular weight PTFE may be prepared by subjecting high molecular weight PTFE (melt viscosity of about 1X 10)⁹Pa.s to about 1X 10¹⁰Pa · s) by irradiation, or PTFE obtained by reducing the molecular weight by using a chain transfer agent in the production of PTFE by polymerizing TFE (japanese unexamined patent publication No. 2009-1745, international publication No. 2010/114033).

The PTFE may be a polymer obtained by polymerizing TFE alone, or a copolymer obtained by copolymerizing TFE with a comonomer (international publication No. 2009/20187, etc.). The amount of the unit derived from TFE is preferably 99.5 mol% or more, more preferably 99.8 mol% or more, and still more preferably 99.9 mol% or more based on the total units contained in the polymer. When the amount is within the above range, the physical properties of PTFE can be maintained. As the comonomer, a fluorine-containing monomer described later is exemplified, and preferably one selected from the group consisting of hexafluoropropylene (hereinafter, also referred to as HFP), perfluoro (alkyl vinyl ether) (hereinafter, also referred to as PAVE), and fluoroalkyl vinyl (hereinafter, also referred to as FAE).

Examples of PTFE having a core-shell structure include PTFE described in, for example, JP-A-2005-527652 and International publication No. 2016/170918. In order to adjust the melt viscosity of the shell portion to the above range, there are a method of reducing the molecular weight of the shell portion by using a chain transfer agent (Japanese patent application laid-open No. 2015-232082, etc.), a method of copolymerizing TFE and the above comonomer at the time of producing the shell portion (Japanese patent application laid-open No. 09-087334), and the like.

In the latter case, the comonomer is preferably used in an amount of about 0.001 mol% to about 0.05 mol% with respect to TFE. In addition, not only the shell portion but also the core portion may be produced by copolymerization. In this case, the comonomer is preferably used in an amount of 0.001 mol% to 0.05 mol% with respect to TFE.

The low-molecular-weight PTFE preferably has a standard specific gravity (hereinafter also referred to as SSG) of 2.14 to 2.22, more preferably 2.16 to 2.20. SSG can be determined according to ASTM D4895-04.

The fluoropolymer F is a copolymer of TFE with a comonomer, and it comprises more than 0.5% by moles of units derived from the comonomer, with respect to the total units comprised by the polymer. The fluoropolymer F can be melt-formed. The melting point of the fluoropolymer F is preferably 260 to 320 ℃, more preferably 280 to 320 ℃, still more preferably 295 to 315 ℃, and particularly preferably 295 to 310 ℃. When the melting point of the fluoropolymer F is not less than the lower limit of the above range, the heat resistance is excellent. When the melting point of the fluoropolymer F is not more than the upper limit of the above range, the melt moldability is excellent.

Examples of the fluoropolymer F include ethylene/tetrafluoroethylene copolymer (ETFE), TFE/HFP copolymer (FEP), TFE/PAVE copolymer (PFA), and the like. The fluoropolymer F is preferably PFA or FEP, more preferably PFA, from the viewpoint of electrical characteristics (dielectric constant, dielectric loss tangent) and heat resistance.

The fluorine-containing resin F is preferably an adhesive fluorine-containing resin having at least one adhesive functional group selected from the group consisting of a carbonyl group-containing group, a hydroxyl group, an epoxy group, an amide group, an amino group, and an isocyanate group and having a melting point of 260 to 320 ℃ (hereinafter also referred to as "fluorine-containing resin F1"). The fluororesin F may be a fluororesin having no adhesive functional group and having a melting point of 260 to 320 ℃ (hereinafter also referred to as "fluororesin F2").

As the fluorine-containing resin F, either one of the fluorine-containing resin F1 and the fluorine-containing resin F2 may be used alone, or the fluorine-containing resin F1 and the fluorine-containing resin F2 may be used in combination.

The fluorine-containing resin F1 contains a fluorine-containing copolymer having an adhesive functional group in the fluorine-containing copolymer. The fluorine-containing resin F2 contains low-molecular-weight PTFE and a fluorine-containing copolymer having no adhesive functional group in the fluorine-containing copolymer.

Further, the fluorine-containing resin F2 may be provided with an adhesive functional group by plasma treatment or the like described later. In this case, the fluorine-containing resin after the treatment is F1.

The fluorine-containing resin F1 may have one or more adhesive functional groups. The adhesive functional group is preferably a carbonyl group in view of interlayer adhesion between the fluorine-containing resin thin film layer and the object to be laminated in the hot-pressed laminate.

Examples of the carbonyl group-containing group include: a group having a carbonyl group between carbon atoms of a hydrocarbon group, a carbonate group, a carboxyl group, a haloformyl group, an alkoxycarbonyl group, an acid anhydride group, and the like.

Examples of the hydrocarbon group in the group having a carbonyl group between carbon atoms of the hydrocarbon group include an alkylene group having 2 to 8 carbon atoms. The carbon number of the alkylene group is the carbon number of a carbon atom not including a carbonyl group.

The haloformyl group is represented by — C (═ O) -X (wherein X is a halogen atom). Examples of the halogen atom in the haloformyl group include a fluorine atom, a chlorine atom and the like, and a fluorine atom is preferable.

The alkoxy group in the alkoxycarbonyl group is preferably an alkoxy group having 1 to 8 carbon atoms, and particularly preferably a methoxy group or an ethoxy group.

1X 10 carbon atoms in the main chain of the fluorine-containing resin F1⁶The content of the adhesive functional group in the fluorine-containing resin F1 is preferably 10 to 60000, more preferably 100 to 50000, still more preferably 100 to 10000, and particularly preferably 300 to 5000. When the content of the adhesive functional group is not less than the lower limit of the above range, the interlayer adhesiveness between the fluorine-containing resin film and the object to be laminated in the hot-pressed laminate is further excellent. When the content of the adhesive functional group is not more than the upper limit of the above range, the fluorine-containing resin F1 is excellent in heat resistance, color tone and the like.

The content of the adhesive functional group can be calculated by obtaining the proportion (mol%) of the unit having the adhesive functional group among all the units constituting the fluorine-containing resin F1 by using, for example, infrared absorption spectrum analysis described in Japanese patent laid-open No. 2007-314720.

Examples of the fluorine-containing resin F1 include a fluoropolymer having a unit having an adhesive functional group or a terminal group having an adhesive functional group. Specifically, PFA having an adhesive functional group, FEP having an adhesive functional group, ETFE having an adhesive functional group, and the like can be cited.

The fluorine-containing resin F1 is preferably the following fluorine-containing polymer F11, from the viewpoint of excellent interlayer adhesion between the fluorine-containing resin film and the object to be laminated in the heat-press laminated body and further excellent electrical characteristics of the fluorine-containing resin film.

Fluoropolymer F11: a fluoropolymer having a unit u1, a unit derived from a cyclic hydrocarbon monomer having an acid anhydride group (hereinafter, also referred to as "acid anhydride monomer") (hereinafter, also referred to as "unit u 2"), and a unit derived from a fluorine-containing monomer (hereinafter, also referred to as "unit u 3") excluding TFE.

Examples of the fluoropolymer F11 include the polymer (X) described in International publication No. 2018/16644.

Examples of the acid anhydride monomer include itaconic anhydride (hereinafter, also referred to as "IAH"), citraconic anhydride (hereinafter, also referred to as "CAH"), 5-norbornene-2, 3-dicarboxylic anhydride (hereinafter, also referred to as "NAH"), and maleic anhydride. The acid anhydride monomer may be used alone or in combination of two or more.

The fluorine-containing monomer constituting the unit u3 is preferably at least one selected from the group consisting of HFP, PAVE and FAE, and particularly preferably PAVE, from the viewpoint of excellent moldability of the fluorine-containing polymer F11, bending resistance of the fluorine-containing resin film, and the like.

As PAVE, CF is mentioned₂＝CFOCF₃、CF₂＝CFOCF₂CF₃、CF₂＝CFOCF₂CF₂CF₃(hereinafter, also referred to as "PPVE") and CF₂＝CFOCF₂CF₂CF₂CF₃、CF₂＝CFO(CF₂)₈F, etc., preferably PPVE.

As FAE, CH is preferred₂＝CH(CF₂)₂F、CH₂＝CH(CF₂)₃F、CH₂＝CH(CF₂)₄F、CH₂＝CF(CF₂)₃H、CH₂＝CF(CF₂)₄H, more preferably CH₂＝CH(CF₂)₄F (hereinafter, also referred to as "PFBE") and CH₂＝CH(CF₂)₂F (hereinafter, also referred to as "PFEE").

The preferable ratio of each unit to the total amount of the unit u1, the unit u2 and the unit u3 in the fluoropolymer F11 is as follows.

The proportion of the unit u1 is preferably 90 to 99.89 mol%, more preferably 95 to 99.47 mol%, and still more preferably 96 to 98.95 mol%.

The proportion of the unit u2 is preferably 0.01 to 3 mol%, more preferably 0.03 to 2 mol%, and still more preferably 0.05 to 1 mol%.

The proportion of the unit u3 is preferably 0.1 to 9.99 mol%, more preferably 0.5 to 9.97 mol%, and still more preferably 1 to 9.95 mol%.

In the fluoropolymer F11, if the ratio of the units is within the above range, the fluorine-containing resin film is more excellent in flame retardancy, chemical resistance and the like.

When the ratio of the unit u2 is within the above range, the interlayer adhesiveness between the fluororesin thin film and the object to be laminated and the interlayer adhesiveness between the fluororesin thin film and the metal layer in the hot-pressed laminate are more excellent.

When the proportion of the unit u3 is in the above range, the fluorine-containing polymer F11 is more excellent in moldability, bending resistance of the fluorine-containing resin film and the like.

The ratio of each unit can be calculated by melt NMR analysis, fluorine content analysis, infrared absorption spectrum analysis, and the like of the fluoropolymer X.

The fluoropolymer F11 may have, in addition to the units u1 to u3, a unit u4 derived from a non-fluorine-containing monomer (not including an acid anhydride monomer).

Examples of the non-fluorine-containing monomer include olefins (e.g., ethylene, propylene, and 1-butene) and vinyl esters (e.g., vinyl acetate). One kind of the non-fluorine-containing monomer may be used alone, or two or more kinds may be used in combination.

The non-fluorine-containing monomer is preferably ethylene, propylene or 1-butene, and particularly preferably ethylene, from the viewpoint of excellent mechanical strength of the fluorine-containing resin film.

Specific examples of the fluoropolymer F11 include: copolymers of TFE, NAH, and PPVE (also described as TFE/NAH/PPVE copolymers, the same applies in the case of other copolymers), TFE/IAH/PPVE copolymers, TFE/CAH/PPVE copolymers, TFE/IAH/HFP copolymers, TFE/CAH/HFP copolymers, TFE/IAH/PFBE/ethylene copolymers, TFE/CAH/PFBE/ethylene copolymers, TFE/IAH/PFEE/ethylene copolymers, TFE/CAH/PFEE/ethylene copolymers, TFE/IAH/HFP/PFBE/ethylene copolymers, and the like.

The fluoropolymer F11 is preferably PFA having an adhesive functional group, more preferably TFE/NAH/PPVE copolymer, TFE/IAH/PPVE copolymer, TFE/CAH/PPVE copolymer.

As the fluorine-containing resin F1, a fluorine-containing polymer having an adhesive functional group as a main chain terminal group can also be used. The fluoropolymer can be produced by a method of polymerizing monomers using a chain transfer agent and a polymerization initiator that provide an adhesive functional group during polymerization of the monomers.

As the chain transfer agent which brings a tacky functional group, a chain transfer agent having a carboxyl group, an ester bond, a hydroxyl group, or the like is preferable. Specific examples thereof include acetic acid, acetic anhydride, methyl acetate, ethylene glycol, and propylene glycol.

As the polymerization initiator for imparting the adhesive functional group, peroxide-based polymerization initiators such as peroxycarbonate, diacylperoxide and peroxyester are preferable. Specifically, there may be mentioned: di-n-propyl peroxydicarbonate, diisopropyl peroxycarbonate, tert-butyl peroxyisopropylcarbonate, bis (4-tert-butylcyclohexyl) peroxydicarbonate, bis (2-ethylhexyl) peroxydicarbonate, and the like.

The fluororesin film of the present invention may further contain a resin other than the fluororesin F, an additive, and the like as necessary within a range not impairing the effects of the present invention.

As the additive, an organic filler, an inorganic filler, and the like are preferable. Examples of the additives include those described in [0070] of International publication No. 2018/16644.

The fluorine-containing resin film of the present invention has Ra (AFM) of at least one surface in the thickness direction thereof of 3.0nm or more. Thus, when an object to be laminated such as a prepreg is laminated on the surface of the fluororesin thin film having an ra (afm) of 3.0nm or more by hot pressing, excellent interlayer adhesiveness can be obtained between the fluororesin thin film and the object to be laminated. In addition, when a base material comprising another material such as a metal is laminated on the surface of the fluororesin thin film having an ra (afm) of 3.0nm or more, excellent interlayer adhesion can be obtained between the fluororesin thin film and the other base material.

The fluorine-containing resin thin film of the present invention may have Ra (AFM) of 3.0nm or more on only one surface in the thickness direction, or Ra (AFM) of 3.0nm or more on both surfaces in the thickness direction.

The fluorine-containing resin film has an Ra (AFM) of 3.0nm or more, preferably 9.0nm or more, and more preferably 12nm or more on at least one surface in the thickness direction. When the amount is within the above range, the fluororesin film of the present invention has excellent adhesion.

The surface of the fluorine-containing resin film having Ra (AFM) of 3.0nm or more preferably has rz (AFM) of 80nm or more, more preferably 100nm or more, and particularly preferably 130nm or more. When the amount is within the above range, the adhesion is improved.

Ra (AFM) is preferably 1 μm or less, and rz (AFM) is preferably 300nm or less.

The fluororesin film of the present invention may be a single-layer film or a multilayer film.

The thickness of the fluorine-containing resin film is preferably 1 to 3000. mu.m. In the case of printed wiring board applications, the thickness of the fluorine-containing resin film is more preferably 1 μm to 2000. mu.m, still more preferably 1 μm to 1000. mu.m, particularly preferably 3 μm to 50 μm, and most preferably 3 μm to 15 μm.

The fluorine-containing resin film preferably has a relative dielectric constant (1MHz) of 2.0 to 3.5, particularly preferably 2.0 to 3.0. When the relative dielectric constant (1MHz) is not more than the upper limit of the above range, it is useful for applications requiring a low dielectric constant such as printed wiring boards. When the relative permittivity (1MHz) is not less than the lower limit of the above range, both the electrical characteristics and the adhesiveness are excellent.

The fluorine-containing resin film preferably has a relative dielectric constant (20GHz) of 2.5 or less, more preferably 2.4 or less, and particularly preferably 2.0 to 2.4. The lower the relative dielectric constant (20GHz), the more excellent the electrical characteristics of the fluorine-containing resin film, and for example, when the fluorine-containing resin film is used for a printed wiring board, excellent transmission efficiency can be obtained.

(method for producing fluorine-containing resin film)

The method for producing the fluorine-containing resin thin film includes a method of surface-treating at least one surface of a fluorine-containing resin thin film containing a fluorine-containing resin F so that Ra (AFM) is 3.0nm or more.

In the case where "ra (afm) is 3.0nm or more" is replaced with "ra (afm) is 3.0nm or more and rz (afm) is 80.0nm or more", the fluorine-containing resin thin film can be produced in the same manner.

Examples of the method for forming the fluorine-containing resin thin film include the following methods: the fluororesin film is obtained by dispersing a resin powder containing the fluororesin F in a liquid medium to obtain a dispersion, forming a film using the dispersion, drying the film, and heating the dried film. Further, the following methods may be mentioned: the fluororesin thin film is obtained by mixing the dispersion liquid with a liquid containing a thermoplastic resin other than the fluororesin F or a raw material thereof or a thermosetting resin or a raw material thereof (hereinafter, these are also collectively referred to as "thermoplastic resin or the like") to obtain a liquid composition, forming a film using the liquid composition, drying the film, and heating the film.

As a method for producing the fluorine-containing resin film, an extrusion molding method, an inflation molding method, or the like may be used.

The resin powder preferably contains a fluorine-containing resin F as a main component. If the fluorine-containing resin F is used as a main component, a resin powder having a high bulk density can be easily obtained. The larger the bulk density of the resin powder is, the more excellent the handling property is. The term "the fluororesin F as a main component" of the resin powder means that the proportion of the fluororesin F to the total amount (100 mass%) of the resin powder is 80 mass% or more. The proportion of the fluorine-containing resin F to the total amount (100 mass%) of the resin powder is preferably 85 mass% or more, more preferably 90 mass% or more, and particularly preferably 100 mass%.

The average particle diameter of the resin powder is preferably 0.3 to 6 μm, more preferably 0.4 to 5 μm, still more preferably 0.5 to 4.5 μm, particularly preferably 0.7 to 4 μm, and most preferably 1 to 3.5 μm. If the average particle diameter of the resin powder is not less than the lower limit of the above range, the resin powder has sufficient fluidity and can be easily handled, and since the average particle diameter is small, the filling rate of the resin powder in the thermoplastic resin or the like can be increased. The higher the filling ratio, the more excellent the electrical characteristics (low dielectric constant, etc.) of the fluororesin thin film formed using the liquid composition. Further, the smaller the average particle size of the resin powder is, the thinner the fluororesin film formed using the liquid composition can be, for example, easily adjusted to a thickness useful for the application to a flexible printed wiring board. If the average particle diameter of the resin powder is not more than the upper limit of the above range, the dispersibility of the resin powder in a liquid medium is excellent. Further, if it is within this range, the adhesiveness is excellent within the range of preferable surface roughness when forming a film.

The average particle diameter of the resin powder was a volume-based cumulative 50% diameter (D50) determined by a laser diffraction/scattering method. That is, the average particle diameter of the resin powder is a particle diameter at a point where the cumulative volume reaches 50% on a cumulative curve obtained by measuring the particle size distribution by a laser diffraction/scattering method and assuming that the total volume of the particle population is 100%.

The resin powder preferably has a volume-based cumulative 90% diameter (D90) of 8 μm or less, more preferably 6 μm or less, and particularly preferably 1.5 to 5 μm. When D90 is not more than the upper limit, the dispersibility of the resin powder in a liquid medium is excellent.

The D90 of the resin powder can be determined by a laser diffraction/scattering method. That is, D90 of the resin powder is a particle size distribution measured by a laser diffraction/scattering method, a cumulative curve is obtained with the total volume of the particle population as 100%, and a point on the cumulative curve where the cumulative volume reaches 90% is the particle size.

The loose-packing bulk density of the resin powder is preferably 0.05g/mL or more, more preferably 0.05 g/mL-0.5 g/mL, and particularly preferably 0.08 g/mL-0.5 g/mL.

The resin powder preferably has a close-packed bulk density of 0.05g/mL or more, more preferably 0.05 g/mL-0.8 g/mL, and particularly preferably 0.1 g/mL-0.8 g/mL.

The larger the loose-packing bulk density or the dense-packing bulk density is, the more excellent the handling property of the resin powder is. In addition, the filling rate of the resin powder in the thermoplastic resin or the like can be increased. If the loose packed bulk density or the dense packed bulk density is not more than the upper limit of the above range, it can be used in a general process.

As the liquid medium, there can be mentioned: water; alcohols such as methanol and ethanol; nitrogen-containing compounds such as N, N-dimethylformamide, N-dimethylacetamide and N-methyl-2-pyrrolidone; sulfur-containing compounds such as dimethyl sulfoxide; ethers such as diethyl ether and dioxane; esters such as ethyl lactate and ethyl acetate; ketones such as methyl ethyl ketone and methyl isopropyl ketone; glycol ethers such as ethylene glycol monoisopropyl ether, cellosolves such as methyl cellosolve and ethyl cellosolve, and the like.

One kind of the liquid medium may be used alone, or two or more kinds may be used in combination. The liquid medium is a compound that does not react with the adhesive fluorine-containing resin.

The dispersion may comprise a surfactant.

The surfactant is not particularly limited as long as it has at least a fluorine-containing group and a hydrophilic group, and may contain a lipophilic group in addition thereto.

The dispersion may further contain a silicone defoaming agent or a fluorine-containing silicone defoaming agent. In particular, in the case of a liquid medium which is a nonaqueous solvent, it is preferable to use a hydrophilic or water-soluble silicone-based defoaming agent in order to allow the defoaming agent to exist at the interface between the liquid medium and the air rather than at the interface between the liquid medium and the fluorine-containing resin F.

The content of the liquid medium in the dispersion liquid is preferably 1 to 1000 parts by mass with respect to 100 parts by mass of the resin powder.

When the dispersion contains a surfactant, the content of the surfactant in the dispersion is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, and particularly preferably 0.3 to 7 parts by mass, based on 100 parts by mass of the resin powder.

When the dispersion contains an antifoaming agent, the content of the antifoaming agent in the dispersion varies depending on the content of the fluorine-containing resin F, and is preferably 1% by mass or less in terms of an active ingredient relative to the total mass of the dispersion.

When the dispersion contains the inorganic filler, the content of the inorganic filler in the dispersion is preferably 0.1 to 300 parts by mass, more preferably 1 to 200 parts by mass, still more preferably 3 to 150 parts by mass, particularly preferably 5 to 100 parts by mass, and most preferably 10 to 60 parts by mass, based on 100 parts by mass of the resin powder.

The liquid composition is a mixture of the dispersion liquid and a liquid containing a thermoplastic resin or the like.

Examples of the thermoplastic resin or the raw material thereof other than the fluorine-containing resin F include thermoplastic resins having a reactive group that reacts with the adhesive functional group, and raw materials thereof. Examples of the reactive group include a carbonyl group, a hydroxyl group, an amino group, and an epoxy group.

Examples of the thermoplastic resin having a reactive group include thermoplastic polyimide (hereinafter, also referred to as "TPI").

Examples of the raw material of the thermoplastic resin having a reactive group include: polyamic acid obtained by polycondensation of a polyvalent carboxylic dianhydride or a derivative thereof and a diamine as a raw material precursor of TPI. The thermoplastic resin may be used alone or in combination of two or more.

As the raw material of the thermoplastic resin, a raw material having a melting point of 280 ℃ or higher when the thermoplastic resin is produced is preferable. Thus, the thin film formed from the liquid composition is easily prevented from thermally expanding (foaming) when exposed to an atmosphere suitable for reflow soldering.

As the thermoplastic resin other than the fluorine-containing resin F or the raw material thereof, a thermoplastic resin having no reactive group or a raw material thereof may also be used. Examples of the thermoplastic resin other than the fluorine-containing resin F having no reactive group include the fluorine-containing resins having no adhesive functional group and having a melting point of less than 260 ℃ or more than 380 ℃ as exemplified in the above-mentioned other resins.

Examples of the thermosetting resin or the raw material thereof include thermosetting resins having a reactive group and raw materials thereof. As the thermosetting resin or the raw material thereof, a thermosetting resin or a raw material thereof having no reactive group may be used.

Examples of the thermosetting resin include: epoxy resins, acrylic resins, phenol resins, polyester resins, polyolefin resins, modified polyphenylene ether resins, polyfunctional cyanate ester resins, polyfunctional maleimide-cyanate ester resins, polyfunctional maleimide resins, vinyl ester resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, melamine-urea copolycondensation resins, fluorine-containing resins having reactive groups (wherein the fluorine-containing resin F1 is excluded), and the like. Among them, epoxy resins, acrylic resins, bismaleimide resins, and modified polyphenylene ether resins are preferable as the thermosetting resin, and epoxy resins and modified polyphenylene ether resins are particularly preferable from the viewpoint of being useful for printed wiring board applications. The thermosetting resin may be used alone or in combination of two or more.

The weight average molecular weight of the epoxy resin is preferably 100 to 1000000, and more preferably 1000 to 100000. When the weight average molecular weight of the epoxy resin is within the above range, the interlayer adhesiveness between a film or the like formed from the liquid composition and another material (metal or the like) is excellent.

The weight average molecular weight of the epoxy resin was determined by Gel Permeation Chromatography (GPC).

Examples of the bismaleimide resin include a resin composition (BT resin) using a bisphenol a type cyanate ester resin and a bismaleimide compound in combination as described in japanese patent application laid-open No. 7-70315, an invention described in international publication No. 2013/008667, and a bismaleimide resin described in the background art thereof.

As a raw material of the thermosetting resin having a reactive group, a precursor (polyamic acid) of an aromatic polyimide is preferable, and a precursor (polyamic acid) of a wholly aromatic polyimide obtained by polycondensation of an aromatic polycarboxylic dianhydride and an aromatic diamine is preferable.

Specific examples of the aromatic polycarboxylic acid dianhydride and the aromatic diamine include those described in [0055] and [0057] of Japanese patent laid-open No. 2012-145676. These may be used alone or in combination of two or more.

The liquid containing the thermoplastic resin or the like may be used as it is in the case where the thermoplastic resin or the like is in a liquid state. When the thermoplastic resin or the like is not in a liquid state, it is sufficient to prepare a liquid obtained by dissolving or dispersing the thermoplastic resin or the like in a liquid medium in which the thermoplastic resin or the like can be dissolved or dispersed. The liquid medium capable of dissolving or dispersing the thermoplastic resin or the like is not particularly limited, and may be appropriately selected from liquid media exemplified as the liquid medium in the dispersion liquid, depending on the kind of the thermoplastic resin or the like.

In the case of using a thermosetting resin or a raw material thereof, the liquid composition may contain a curing agent. Examples of the curing agent include a thermal curing agent (such as melamine resin and polyurethane resin) and an epoxy curing agent (such as novolac-type phenol resin, isophthalic dihydrazide and adipic dihydrazide).

The content of the resin powder in the liquid composition is preferably 5 to 500 parts by mass, more preferably 10 to 400 parts by mass, and particularly preferably 20 to 300 parts by mass, relative to 100 parts by mass of the thermoplastic resin or the like. When the content of the resin powder is not less than the lower limit of the above range, the fluorine-containing resin film formed using the liquid composition is excellent in electrical characteristics. When the content of the resin powder is not more than the upper limit of the above range, the resin powder is easily uniformly dispersed in the liquid composition, and the fluorine-containing resin film formed using the liquid composition has excellent mechanical strength.

The content of the liquid medium in the liquid composition is preferably 1 to 1000 parts by mass, more preferably 10 to 500 parts by mass, and particularly preferably 30 to 250 parts by mass, based on 100 parts by mass of the total of the resin powder, the thermoplastic resin, and the like. If the content of the liquid medium is not less than the lower limit of the above range, the viscosity of the liquid composition is not excessively high, and the coating property at the time of film formation is good. If the content of the liquid medium is not more than the upper limit of the above range, the viscosity of the liquid composition is not excessively low, the coating property at the time of film formation is good, and the amount of the liquid medium used is small, so that the appearance defect of the film-formed product due to the step of removing the liquid medium is less likely to occur.

When the liquid medium is contained in the liquid containing the thermoplastic resin or the like, the content of the liquid medium in the liquid composition is a content obtained by adding the liquid medium in the dispersion liquid and the liquid medium in the liquid containing the thermoplastic resin or the like.

When the liquid composition contains a curing agent, the content of the curing agent in the liquid composition is preferably 0.5 to 2.0 equivalents, and more preferably 0.8 to 1.2 equivalents, relative to the amount of the reactive group contained in the thermosetting resin or the raw material thereof.

As a method for forming a film of a dispersion or a liquid composition (hereinafter, referred to as a liquid composition or the like), it is preferable to form a film containing the liquid composition or the like by coating on the surface of a support and coating on the support. After the film of the liquid composition or the like is formed, the liquid medium is volatilized by a method such as heating the film of the liquid composition or the like, and a solid film from which the liquid medium is removed or a non-flowable film from which at least a part of the liquid medium is removed is formed. Hereinafter, the removal of the liquid medium is also referred to as "drying", and the application operation is also referred to as "application".

In the drying, it is not always necessary to completely remove the liquid medium, and it is sufficient that the coating film is allowed to stably maintain the film shape. At the time of drying, it is preferable to remove 50% by mass or more of the liquid medium contained in the liquid composition or the like.

The drying method is not particularly limited, and examples thereof include the methods described in [0091] to [0094] of International publication No. 2018/16644.

When a raw material of a thermoplastic resin is used in a liquid containing the thermoplastic resin or the like, the raw material of the thermoplastic resin is heated after drying to be a thermoplastic resin. For example, when a polyamic acid is used as a raw material of TPI, the polyamic acid is imidized by heating after drying to prepare TPI. In this case, the heating temperature after drying may be set to 350 to 550 ℃.

When a thermosetting resin is used in a liquid containing a thermoplastic resin or the like, the thermosetting resin is cured by heating after drying. In the case of using a raw material of a thermosetting resin (e.g., polyamic acid which is a precursor of aromatic polyimide), the raw material of the thermosetting resin is heated after drying to be a thermosetting resin, and then cured. The heating temperature after drying may be appropriately set according to the kind of the thermosetting resin, and for example, when an epoxy resin is used, it may be set to 50 to 250 ℃.

The drying and subsequent heating may be carried out continuously. The heating after drying may be performed in one step, or may be performed in two or more steps at different temperatures.

In the case of producing the fluorine-containing resin film of the present invention by forming a film from the above-mentioned dispersion or liquid composition containing a surfactant, the residual amount of the surfactant in the fluorine-containing resin film is preferably less than 8%. When the dielectric constant is within this range, the dielectric constant is low and the electrical characteristics are excellent.

The surface treatment for adjusting Ra (AFM) of at least one surface of the fluorine-containing resin thin film to 3.0nm or more is preferably a plasma treatment.

The plasma irradiation apparatus used for the plasma treatment is not particularly limited, and examples thereof include apparatuses using a high-frequency induction system, a capacitive coupling electrode system, a corona discharge electrode-plasma jet system, a parallel flat plate type, a remote plasma type, an atmospheric pressure plasma type, an ICP type high-density plasma type, and the like.

The gas used for the plasma treatment is not particularly limited, and examples thereof include oxygen, nitrogen, a rare gas (such as argon), hydrogen, ammonia, and the like, and a rare gas or nitrogen is preferable, and argon is particularly preferable. These may be used alone or in combination of two or more.

As the gas used in the plasma treatment, argon, a mixed gas of argon and hydrogen or nitrogen, or a mixed gas of argon, nitrogen and hydrogen is preferable. The oxygen concentration in the plasma treatment is preferably 500ppm or less, and may be 0 ppm.

The atmosphere for plasma treatment is preferably an atmosphere in which the volume fraction of the rare gas or nitrogen is 50% by volume or more, more preferably an atmosphere in which the volume fraction of the rare gas or nitrogen is 70% by volume or more, still more preferably an atmosphere in which the volume fraction of the rare gas or nitrogen is 90% by volume or more, and particularly preferably an atmosphere in which the volume fraction of the rare gas or nitrogen is 100% by volume. When the volume fraction of the rare gas or the nitrogen gas is not less than the lower limit, the surface of the fluorine-containing resin thin film can be easily renewed to a surface after plasma treatment having an Ra (AFM) of not less than 3.0 nm.

In the plasma treatment, ra (afm) on the surface of the thin film increases as the treatment is performed, but when the treatment is performed excessively, ra (afm) that has been increased first tends to decrease again. Therefore, the energy of generated electrons (about 1eV to about 10eV) is controlled and the processing time is set so that the processing does not become excessive by adjusting the electrode pitch, the output power of the device, and the like. When the RF output power in the plasma processing apparatus is adjusted, the RF output power is preferably adjusted to 100W to 400W.

The same applies to the case where "surface treatment in which ra (afm) is adjusted to 3.0nm or more" is replaced with "surface treatment in which ra (afm) is adjusted to 3.0nm or more and rz (afm) is adjusted to 80.0nm or more".

The water contact angle of the surface of the fluorine-containing resin film after the plasma treatment is preferably 114 ° or less, and more preferably 100 ° or less. The smaller the contact angle, the better the adhesiveness with other materials.

The surface of the fluorine-containing resin thin film after the plasma treatment has an Ra (AFM) of 3.0nm or more and has a wetting tension of preferably 30mN/m or more, more preferably 30mN/m or more and 70mN/m or less, and still more preferably 40mN/m or more and 65mN/m or less. The larger the wetting tension, the more excellent the adhesiveness with other materials.

The fluorine-containing resin thin film after plasma treatment preferably has a composition ratio of ra (afm) of 3.0nm or more to oxygen atoms in the total of three elements of carbon atoms, fluorine atoms, and oxygen atoms of preferably 1% or more, more preferably 1% or more and 9% or less. When the composition ratio of oxygen atoms is within the above range, good adhesiveness can be easily provided. The fluorine-containing resin film of the present invention has a composition ratio of oxygen atoms on the surface before plasma treatment of 0% or more, and more preferably 0.5% or more.

The fluorine-containing resin thin film after plasma treatment preferably has a composition ratio of fluorine atoms to the total of three elements of carbon atoms, fluorine atoms and oxygen atoms in the surface having an ra (afm) value of 3.0nm or more. When the composition ratio of fluorine atoms is within the above range, good adhesiveness can be easily provided. Further, if the composition ratio of fluorine atoms is 25% or more, the electrical characteristics as a printed wiring board are improved.

[ laminate ]

The laminate of the present invention is the laminate as described above: the laminate comprises a layer A containing a material containing the fluorine-containing resin F, and a layer B containing a material not containing the fluorine-containing resin F, wherein at least one surface of the laminate is constituted by the surface of the layer A, and wherein at least one surface of the layer A of the laminate has a surface having an Ra (AFM) of 3.0nm or more. The Ra (AFM) of the layer A is 3.0nm or more, and more preferably rz (AFM) is 80.0nm or more. The laminate of the present invention is particularly effective as a laminate for laminating an object to be laminated on the surface of the layer a by hot pressing.

The laminate of the present invention has a laminate structure in which at least one layer a is the outermost layer. Examples of the laminate structure of the laminate of the present invention include a structure in which a layer a and a layer B are laminated in this order (also referred to as layer a/layer B, the same applies to other laminate structures), and layer a/layer B/layer a.

The material constituting the layer a is a material containing a fluorine-containing resin F, and preferably contains a material constituting the fluorine-containing resin film of the present invention. The material constituting the layer a may contain only the fluorine-containing resin F, and in this case, the fluorine-containing resin F may be a fluorine-containing resin F2 having no adhesive functional group such as PTFE.

Examples of the layer a include a layer containing the fluororesin film of the present invention and a fluororesin layer formed from a resin powder containing a fluororesin F by coating or the like. The layer a may be a single layer or a multilayer of two or more layers.

When both surfaces of the laminate of the present invention are the surfaces of the layer a, only one surface may be a surface having ra (afm) of 3.0nm or more, or both surfaces may be a surface having ra (afm) of 3.0nm or more. The preferred ranges of the thickness and the relative dielectric constant of the layer a having a surface with ra (afm) of 3.0nm or more are the same as those of the fluorine-containing resin thin film. In the case where the laminate of the present invention has the second layer a having a surface with ra (afm) of not less than 3.0nm, the preferred ranges of the thickness and the relative permittivity of the second layer a are also preferably the same as those of the fluorine-containing resin thin film.

The same applies to the case where "Ra (AFM)" is 3.0nm or more "is replaced with" Ra (AFM) is 3.0nm or more and rz (AFM) is 80.0nm or more ".

The material constituting the layer B is a material not containing the fluorine-containing resin F, and examples thereof include resin materials such as a fluorine-containing resin other than the fluorine-containing resin F, a thermoplastic resin having no fluorine atom, and a thermosetting resin having no fluorine atom. Further, the resin material may be an inorganic material such as metal or glass, or a composite material of an inorganic material and a resin material (e.g., a prepreg described later). As a material constituting the layer B, a metal is particularly preferable.

Layer B is preferably formed from a substrate comprising the above-described materials. Examples thereof include a film containing the above resin material, a film containing the above inorganic material, a film containing a combination of these films, and a substrate containing a molded article other than a film. Particularly preferred are a substrate comprising a metal thin film called a metal foil, and a film-like substrate comprising a resin material layer and a thin layer comprising a metal material, and these substrates are hereinafter referred to as metal substrates.

The layer B may be a single layer or a multilayer of two or more layers. In addition, a filler may be contained in the layer B, and for example, a fluorine resin-containing powder may be contained. As layer B, a layer comprising a metal substrate is useful for printed wiring board applications.

Examples of the metal substrate include a metal foil, a resin film having a metal plating layer on the surface thereof, and a resin film having a metal deposition layer on the surface thereof (metal deposition resin film).

Examples of the metal constituting the metal base include iron, stainless steel, aluminum, copper, brass, nickel, zinc, titanium, and alloys of these metals. In the case of printed circuit board applications, copper or copper alloys, stainless steel, nickel or nickel alloys (including 42 alloys), aluminum or aluminum alloys are preferred, with copper being particularly preferred. As the metal base material, a copper foil such as a rolled copper foil or an electrolytic copper foil is particularly preferable.

A rust-proof layer (e.g., an oxide coating such as chromate) or a heat-resistant layer may be formed on the surface of the metal substrate. In addition, in order to improve adhesion to the layer a, the surface of the metal base material may be subjected to a coupling agent treatment or the like.

The thickness of the metal base is not particularly limited, and a thickness capable of sufficiently functioning may be selected according to the application.

Examples of the metal vapor-deposited resin film include a film obtained by vapor-depositing the metal on one surface or both surfaces of a heat-resistant resin film by a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or an ion plating method.

The resin film used as the substrate for the layer B is preferably a heat-resistant resin film or a thermosetting resin film.

The heat-resistant resin film is a film containing one or more heat-resistant resins. However, the heat-resistant resin film does not contain a fluorine-containing resin. The heat-resistant resin film may be a single-layer film or a multilayer film.

The heat-resistant resin is a polymer compound having a melting point of 280 ℃ or higher or a resin having a melting point of JIS C4003: 2010(IEC 60085: 2007) wherein the maximum continuous use temperature is 121 ℃ or higher.

Examples of the heat-resistant resin include: liquid crystal polymers (hereinafter, also referred to as "LCP") such as polyimide (aromatic polyimide, etc.), polyarylate, polysulfone, polyarylsulfone (polyethersulfone, etc.), aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, and liquid crystal polyester.

LCPs are thermoplastic polymers capable of forming an optically anisotropic melt phase. The optical anisotropy at the time of melting can be confirmed, for example, by placing a sample on a thermal stage, heating the sample at an elevated temperature in a nitrogen atmosphere, and observing the transmitted light of the sample.

Examples of the LCP include thermoplastic liquid crystal polyesters, thermoplastic liquid crystal polyester amides in which amide bonds are introduced, and the like.

Further, the polymer may be one in which an isocyanate-derived bond such as an imide bond, a carbonate bond, a carbodiimide bond, or an isocyanurate bond is further introduced into the aromatic polyester or the aromatic polyester amide. Thermoplastic liquid crystalline polyesters are particularly preferred.

The melting point of the LCP is preferably from 280 ℃ to 360 ℃, more preferably from 290 ℃ to 350 ℃.

Examples of LCPs include: vecstar (trade name, manufactured by clony corporation), BIAC (trade name, manufactured by japan golay corporation), "LAPEROS" manufactured by precious plastics, "VECTRA" manufactured by selanis, "UENOLCP" manufactured by japan pharmaceuticals, "sumikasher LCP" manufactured by sumitomo chemical, "XYDAR" manufactured by solvay crystal POLYMERS, "XYDAR" manufactured by JX japanese crystal energy, and "sigeras" manufactured by dongli corporation.

The heat-resistant resin film is preferably a polyimide film or a liquid crystal polyester film, and more preferably a liquid crystal polyester film from the viewpoint of electrical characteristics. The surface of the heat-resistant resin film on the layer a side may be subjected to a surface treatment such as corona treatment or plasma treatment.

The thermosetting resin film may be a single-layer film or a multilayer film. The thermosetting resin constituting the thermosetting resin film may be the same thermosetting resin as that described in the description of the liquid composition. As the thermosetting resin used for the layer B, a thermosetting resin (hereinafter, also referred to as "thermosetting resin H") capable of forming the layer B at a temperature equal to or lower than the melting point of the fluorine-containing resin F is used.

As the resin constituting the resin film, polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyphenylene ether, or the like can be used.

The ratio a/B of the thickness of the layer a to the thickness of the layer B in the laminate of the layer a containing the fluorine-containing resin F and the layer B containing the thermosetting resin H is preferably 0.3 to 3.0. If the thickness ratio A/B is 0.3 or more, the effect of lowering the relative dielectric constant is high. If the thickness ratio A/B is 3.0 or less, the linear expansion coefficient becomes small.

In the laminate, when the layer a and the layer B containing the thermosetting resin H are directly laminated, the peel strength at the interface between the layer a and the layer B is preferably 5N/10mm or more, more preferably 7N/10mm or more, and further preferably 8N/10mm or more.

The relative dielectric constant (20GHz) of the laminate including the layer B containing the thermosetting resin H is preferably less than 3.6, more preferably 3.55 or less, and particularly preferably 3.20 or less. The lower the relative dielectric constant (20GHz) of the laminate, the more excellent transmission efficiency can be obtained when the laminate is used for a substrate of a printed wiring board.

The dielectric loss tangent (20GHz) of the laminate including the layer B containing the thermosetting resin H is preferably 0.01 or less, more preferably 0.007 or less, and particularly preferably 0.005 or less. The lower the dielectric loss tangent (20GHz) of the laminate, the more excellent transmission efficiency can be obtained when the laminate is used for a substrate of a printed wiring board.

Preferred examples of the laminate include: the layer B contains a thermosetting resin H, the laminate has a structure in which the layer A and the layer B are directly laminated, the peel strength of the interface between the directly laminated layer A and layer B is 5N/10mm or more, and the relative dielectric constant (20GHz) of the laminate is less than 3.6. In this case, it is more preferable that the composition ratio of oxygen atoms is 1% or more and the composition ratio of fluorine atoms is 25% or more and 65% or less with respect to the total of three elements of carbon atoms, fluorine atoms and oxygen atoms in the surface of the layer a in contact with the layer B.

Specific examples of the laminate of the present invention include the laminate 1 illustrated in fig. 1. The laminate 1 includes a layer a10 and a layer B12, and the layer B12 is laminated on the first surface 10a side in the thickness direction of the layer a 10.

In the laminate 1, the ra (afm) of the second surface 10B of the layer a10 on the side opposite to the layer B12 was adjusted to 3.0nm or more. Thus, when the object to be laminated is laminated on the second surface 10b side of the layer a10 of the laminate 1, excellent interlayer adhesiveness can be obtained.

In the laminate 1, ra (afm) of the first surface 10a of the layer a10 may be adjusted to 3.0nm or more. When the layer B12 is a glass member or a resin film, it is preferable to adjust ra (afm) of the first surface 10a to 3.0nm or more in view of interlayer adhesion between the layer a10 and the layer B12. In the case where the layer B12 is a metal layer, sufficient interlayer adhesion can be obtained between the layer a10 and the layer B12 even if ra (afm) of the first surface 10a is not 3.0nm or more.

The laminate of the present invention may be the laminate 2 illustrated in fig. 2. The laminate 2 includes a first layer a20, a layer B22 laminated on the first surface 20a side in the thickness direction of the first layer a20, and a second layer a24 laminated on the layer B22 opposite to the first layer a 20.

In the laminate 2, ra (afm) of the second surface 20B of the first layer a20 on the side opposite to the layer B22 was adjusted to 3.0m or more, and ra (afm) of the second surface 24B of the second layer a24 on the side opposite to the layer B22 was adjusted to 3.0nm or more. Thus, excellent interlayer adhesiveness can be obtained when the object to be laminated is laminated on the second surface 20b side of the first layer a20 and the second surface 24b side of the second layer a24 of the laminated body 2. In the laminate 2, ra (afm) of the first surface 20a of the first layer a20 and the first surface 24a of the second layer a24 may be adjusted to 3.0nm or more.

In the specific example of the laminate, the same applies to the case where "ra (afm) is adjusted to 3.0nm or more" is replaced with "ra (afm) is adjusted to 3.0nm or more and rz (afm) is adjusted to 80.0nm or more".

The present invention can provide a laminate of various forms. The present invention also provides a laminate comprising a layer a and a layer B, wherein the layer a comprises a fluororesin having a melting point of 260 to 380 ℃ and the layer B comprises a substrate other than the layer a, and the laminate comprises a structure obtained by directly laminating the layer a and the layer B, the peel strength at the interface between the layer a and the layer B after direct lamination is 5N/10mm or more, and the relative dielectric constant (20GHz) of the laminate is less than 3.6. In this case, the material forming the layer B is preferably a thermosetting resin forming the layer B at a temperature equal to or lower than the melting point of the fluororesin or a prepreg described later, and particularly preferably a prepreg described later. The laminate is obtained in a low temperature region of the melting point or less of the fluororesin, and therefore has excellent electrical characteristics such as relative permittivity.

(method of producing laminate)

As a method for producing the laminate of the present invention, the following method is preferred: a laminate having a layer A comprising a fluorine-containing resin F and a layer B is produced, and then the surface of the layer A of the resulting laminate is subjected to a surface treatment so that Ra (AFM) becomes 3.0nm or more.

As a method for producing a laminate having the layer a and the layer B, the following method can be mentioned: a resin powder containing a fluorine-containing resin F is applied onto the surface of the base material as layer B, thereby forming layer a on the base material as layer B. In this case, the resin powder may be powder-coated on the surface of the base material as the layer B by a gravure coating method, a microgravure coating method, a gravure offset printing method, a knife coating method, a kiss roll coating method, a bar coating method, a die coating method, a jet wire bar coating method, a slot die coating method, or the like, using the dispersion or the liquid composition described above, to form a film.

The surface treatment of the layer a surface of the laminate so that ra (afm) becomes 3.0nm or more may be performed by the same method as that described in the method for producing a fluorine-containing resin thin film.

The laminate of the present invention can also be produced by laminating a fluorine-containing resin thin film (not the fluorine-containing resin thin film of the present invention described above, in which ra (afm) on the surface of the fluorine-containing resin F is not 3.0nm or more, unlike ra (afm) on the surface) and a base material as the layer B, and subjecting the surface of the fluorine-containing resin thin film of the obtained laminate to a surface treatment so that ra (afm) is 3.0nm or more.

The fluorine-containing resin film of the present invention may be laminated on a substrate as the layer B to form a laminate. For example, a method of laminating a fluorine-containing resin thin film having at least one surface of ra (afm) of 3.0nm or more with a base material as the layer B so that the surface having ra (afm) of 3.0nm or more becomes the surface of the laminate to obtain a laminate is mentioned. Further, the surface of the fluorine-containing resin F layer of the laminate obtained by laminating a base material as the layer B on the surface side of the fluorine-containing resin thin film having ra (afm) of 3.0nm or more on only one surface may be subjected to a surface treatment so that ra (afm) becomes 3.0nm or more.

In the above-described method for producing a laminate, the same applies to the case where "ra (afm) is 3.0nm or more" is replaced with "ra (afm) is 3.0nm or more and rz (afm) is 80.0nm or more".

A laminate having a copper foil layer as layer B can be produced as follows: the method for producing the resin layer a includes the steps of using a copper foil as a substrate, applying a liquid composition to one surface of the copper foil to form a film of the liquid composition, then removing the liquid medium by heat drying, continuing to heat to melt the resin powder, and then cooling to form the layer a which is a uniform resin layer without unmelted particles. As described above, resin layers may be formed on both surfaces of the copper foil.

Copper foil used was a copper foil based on JIS C6515: the maximum height Rz of the surface roughness measured by 1998(IEC 61249-5-1: 1995) is preferably 1nm or more and 2.5 μm or less. In consideration of electrical characteristics, a copper foil having a small surface roughness is preferable. The fluorine-containing resin film of the present invention may be laminated on a copper foil having a small surface roughness.

The film formation, the heat drying, and the melting of the resin powder of the liquid composition may be performed under the aforementioned conditions. For example, in the case of heating after drying by heating with a heat roll, a laminate of an unmelted resin layer and a copper foil after drying is brought into contact with a heat-resistant roll and conveyed while being irradiated with far infrared rays, whereby the unmelted resin layer can be made into a molten resin layer. The transport speed of the roller is not particularly limited, but is preferably 4.7 m/min to 0.31 m/min in the case of using a heating furnace having a length of 4.7m, for example. In addition, in order to efficiently heat the entire film in a short time, a heating furnace having a length of 2.45m may be used, and the heating furnace may be set to 4.7 m/min to 2.45 m/min.

The heating temperature is not particularly limited, and when the residence time of the heating furnace is set to 1 minute, it is preferably 330 to 380 ℃, and more preferably 350 to 370 ℃. The temperature can also be reduced by increasing the residence time.

The thickness of the layer A of the laminate to be produced is preferably 15 μm or less, more preferably 10 μm or less, and particularly preferably 8 μm or less. However, from the viewpoint of electrical characteristics, it is preferably 1 μm or more. If the upper limit of the above range is not more than the upper limit, warpage can be suppressed even in the case of an asymmetric layer structure of the resin layer (layer a)/the copper foil (layer B). The warpage rate of the laminate is preferably 25% or less, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 7% or less. If the warpage is not more than the upper limit, the workability in the molding process when processing into a printed wiring board is excellent, and the dielectric characteristics as a printed wiring board are excellent.

Further, warpage can be further suppressed by using a liquid composition containing a filler such as silica or PTFE, or a liquid composition containing a fluorine-containing resin such as TFE/PAVE copolymer, TFE/HFP copolymer, or PCTFE (except for the fluorine-containing polymer F11) as the fluorine-containing resin F. The thickness of layer a of the laminate comprising the filler is preferably 200 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less. However, from the viewpoint of electrical characteristics, it is preferably 1 μm or more.

The method of laminating the fluororesin film of the present invention on the surface of the base material as the layer B may be a method using hot pressing. The temperature of the hot press when laminating the fluorine-containing resin film on the surface of the base material as the layer B is preferably not more than the melting point of the fluorine-containing resin F, and more preferably 140 to 250 ℃. Hot pressing at a melting point of the base material as the layer B, which is lower than the melting point of the fluorine-containing resin F, can be performed.

However, in the case of a base material as the layer B having a higher melting point than the fluorine-containing resin F like a liquid crystal polymer, hot pressing may be performed at a temperature lower by 5 degrees or more than the melting point of the base material as the layer B.

[ method for producing Hot-pressed laminate ]

The method for producing a hot-pressed laminate of the present invention is a method for bonding a laminate object to the surface of the fluororesin thin film of the present invention or the laminate of the present invention having an ra (afm) of 3.0nm or more by hot pressing.

Note that, the hot-pressed laminate can be similarly manufactured also in the case where "on the surface having ra (afm) of 3.0nm or more" is replaced with "on the surface having ra (afm) of 3.0nm or more and rz (afm) of 80.0nm or more".

Examples of the object to be laminated include a prepreg, a glass member, and a ceramic member. Among these, the present invention is effective when a prepreg is used as a lamination object.

Examples of the prepreg include a prepreg obtained by impregnating a reinforcing fiber sheet with a matrix resin.

Examples of the reinforcing fiber sheet include a reinforcing fiber bundle containing a plurality of reinforcing fibers, a woven fabric obtained by weaving the reinforcing fiber bundle, a unidirectional reinforcing fiber bundle obtained by doubling a plurality of reinforcing fibers in one direction, a unidirectional woven fabric composed of the unidirectional reinforcing fiber bundle, a product obtained by combining these, a product obtained by stacking a plurality of reinforcing fiber bundles, and the like.

The reinforcing fiber is preferably a continuous long fiber having a length of 10mm or more. The reinforcing fibers need not be continuous over the entire length in the length direction or the entire width in the width direction of the reinforcing fiber sheet, and may be broken at the middle portion.

Examples of the reinforcing fibers include inorganic fibers, metal fibers, and organic fibers.

As the inorganic fibers, there can be mentioned: carbon fibers, graphite fibers, glass fibers, silicon carbide fibers, silicon nitride fibers, alumina fibers, silicon carbide fibers, boron fibers, and the like.

Examples of the metal fibers include aluminum fibers, brass fibers, and stainless steel fibers.

As the organic fiber, there can be mentioned: aromatic polyamide fiber, aramid fiber, poly (p-phenylene benzobisoxazole)

Oxazole (PBO) fibers, polyphenylene sulfide fibers, polyester fibers, acrylic fibers, nylon fibers, polyethylene fibers, and the like.

The reinforcing fibers may be surface-treated reinforcing fibers.

One kind of the reinforcing fiber may be used alone, or two or more kinds may be used in combination.

In printed wiring board applications, glass fibers are preferred as the reinforcing fibers.

The matrix resin may be a thermoplastic resin or a thermosetting resin. The present invention is particularly effective when a thermoplastic resin having a melting point of 280 ℃ or lower or a thermosetting resin having a thermosetting temperature of 280 ℃ or lower is used as the matrix resin. The matrix resin may be used alone or in combination of two or more.

The matrix resin of the prepreg is preferably at least one selected from the group consisting of epoxy resin, polyphenylene oxide, polyphenylene ether, and polybutadiene.

The matrix resin is preferably a thermosetting resin. The thermosetting resin may be the same as the thermosetting resin mentioned in the description of the liquid composition. The thermosetting resin is preferably at least one selected from the group consisting of epoxy resins, polyphenylene oxides, polyphenylene ethers, and polybutadienes.

As the thermoplastic resin, there can be mentioned: examples of the resin include polyester resins (e.g., polyethylene terephthalate), polyolefin resins (e.g., polyethylene), styrene resins (e.g., polystyrene), polycarbonates, polyimides (e.g., aromatic polyimide), polyarylates, polysulfones, polyarylsulfones (e.g., polyethersulfone), aromatic polyamides, aromatic polyetheramides, polyphenylene sulfides, polyaryletherketones, polyamideimides, liquid crystal polyesters, polyphenylene oxides, PTFE, TFE/PAVE copolymers, TFE/HFP copolymers, and fluorine-containing resins such as PCTFE.

When the matrix resin is a thermosetting resin, the curing temperature of the thermosetting resin is preferably not higher than the melting point of the fluorine-containing resin, and particularly preferably 120 to 300 ℃.

The thickness of the prepreg is preferably 10 μm or more and 5mm or less, more preferably 30 μm or more and 3mm or less, and particularly preferably 80 μm or more and 1mm or less. However, the thickness of the prepreg may be appropriately set according to the substrate.

The prepreg may be available under the following trade name.

R-G520, R-1410W, R-1410A, R-1410E of GX series "メグトロ ン" (MEGTRON) manufactured by Sonar corporation; R-1410W, R-1410A, R-1410E of MEGTRON series; r-5680, R-5680(J), R-5680(NJ), R-5670(N), R-5620S, R-5620, R-5630, R-1570 of MEGTRON series; HIPER series R-1650V, R-1650D, R-1650M, R-1650E, R-5610, CR-5680(N) and CR-5680 (J).

GEA-770G, GEA-705G, GEA-700G, GEA-679FG, GEA-679F (R), GEA-78G, TD-002, GEA-75G, GEA-67, and GEA-67G manufactured by Hitachi chemical industries, Ltd.

EI-6765 manufactured by Sumitomo Bakelite, R-5785 manufactured by Songa.

GEPL-190T, GEPL-230T, GHPL-830X TypeA, GHPL-830NS, GHPL-830NSR, GHPL-830NSF manufactured by Mitsubishi gas chemical company.

GEPL-190T, GEPL-230T, GHPL-830X TypeA, GHPL-830NS, GHPL-830NSR, GHPL-830NSF manufactured by fighting mountain company.

SP120N, S1151G, S1151GB, S1170G, S1170GB, S1150G, S1150GB, S1140F, S1140FB, S7045G, SP175M, S1190B, S1170, S0701, S1141KF, S0401KF, S1000-2M, S1000-2MB, S1000-2B, S1000, S1000B, S1000H, S1000HB, S7136H, S7439 and S7439B manufactured by Guangdong Shengyi science and technology company.

NY1135, NY1140, NY1150, NY1170, NY2150, NY2170, NY9135, NY9140, NY9600, NY9250, NY9140HF, NY6200, NY6150, NY3170LK, NY6300, NY3170M, NY6200, NY3150HF CTI600, NY3170HF, NY3150D, NY3150HF, NY2170H, NY2170, NY2150, NY2140, NY1600, NY1140, NY9815HF, NY9810HF, NY9815, NY9810, manufactured by shanghai asia.

IT-180GN, IT-180I, IT-180A, IT-189, IT-180, IT-258GA3, IT-158, IT-150GN, IT-140, IT-150GS, IT-150G, IT-168G1, IT-168G2, IT-170G, IT-170GRA1, IT-958G, IT-200LK, IT-200D, IT-150DA, IT-170GLE, IT-968G, IT-968G SE, IT-968 and IT-968SE manufactured by Unilocene.

UV BLOCK FR-4-86, NP-140TL/B, NP-140M TL/B, NP-150R/TL/B, NP-170R/TL/B, NP-180R/TL/B, NPG R/TL/B, NPG-151, NPG-150N, NPG-150LKHD, NPG-170N, NPG-170R/TL/B, NPG-171, NPG-170D R/TL/B, NPG-180ID/B, NPG-180IF/B, NPG-180IN/B, NPG-180INBK/B (BP), NPG-186, NPG-200R/TL, NPG-200WT, FR-4-86PY, FR-140TL PY manufactured by southern Asia Plastic company, NPG-PY R/TL, CEM-3-92PY, CEM-3-98, CEM-3-01PY, CEM-3-01HC, CEM-3-09HT, CEM-3-10, NP-LDII, NP-LDIII, NP-175R/TL/B, NP-155F R/TL/B, NP-175F R/TL/B, NP-175F BH, NP-175FM BH.

ULVP series and LDP series manufactured by Taiwan science and technology.

A11, R406N, P25N, Terra Green, I-Tera MT40, IS680AG, IS680, Astra MT77, G200, DE104, FR408, ED130UV, FR406, IS410, FR402, FR406N, IS420, IS620I, 370TURBO, 254, I-Speed, FR-408HR, IS415, 370HR, all of which are manufactured by ISOLA group.

NY9000, NX9000, NL9000, NH9000, N9000-13RF, N8000Q, N8000, N7000-1, N7000-2HT/-3, N7000-3, N5000-30, N-5000-32, N4000-12SI, N4000-13SI, N4000-13EP SI, N4350-13RF, N4380-13RF, N4800-20SI, Metarwave 1000, Metarwave 2000, Metarwave 3000, Metarwave 4000, Mercury 9350, N4000-6FC, N4000-7SI, N4000-11, N4000-29 manufactured by PARK ELECTRECHOMICAL.

RO4450B, RO4450F, CLTE-P, 3001 binding Film, 2929 binding ply, CuClad 6700 binding Film, ULTRALAM 3908 binding ply, CuClad 6250 binding Film, manufactured by ROGERS.

ES-3329, ES-3317B, ES-3346, ES-3308S, ES-3310A, ES-3306S, ES-3350, ES-3352, ES-3660, ES-3351S, ES-3551S, ES-3382S, ES-3940, ES-3960V, ES-3960C, ES-3753, ES-3305, ES-3615, ES-3306S, ES-3506S, ES-3308S, ES-3317B, ES-3615 manufactured by Lichang industries.

The structure of the hot-pressed laminate is not particularly limited, and there may be mentioned: metal layer (layer B)/resin layer (layer a)/object to be laminated/resin layer (layer a)/metal layer (layer B), metal layer/object to be laminated/resin layer (fluororesin film)/object to be laminated/metal layer, and the like. For example, there may be mentioned a structure of metal layer (layer B)/resin layer (layer a)/laminate object/resin layer (layer a)/metal layer (layer B) including a laminate object including a resin layer containing a fluorine-containing resin F (for example, only fluorine-containing resin F1, or a mixture of fluorine-containing resin F1 and fluorine-containing resin F2) and a fluorine-containing resin F (for example, only fluorine-containing resin F1, a mixture of fluorine-containing resin F1 and fluorine-containing resin F2, or only fluorine-containing resin F2), and glass cloth and a filler may be further contained in each layer.

The thickness of the resin layer is preferably 15 μm or less, more preferably 10 μm or less, and particularly preferably 8 μm or less. However, from the viewpoint of electrical characteristics, it is preferably 1 μm or more. Further, warpage can be further suppressed by using a liquid composition containing a filler such as silica or PTFE, or a liquid composition containing another fluorine-containing resin such as TFE/PAVE copolymer, TFE/HFP copolymer, or polychlorotrifluoroethylene as the fluorine-containing resin F.

The thickness of the resin layer of the hot-pressed laminate in which the resin layer contains a filler is preferably 200 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less. However, from the viewpoint of electrical characteristics, it is preferably 1 μm or more.

The thickness of the object to be laminated is preferably 0.1 to 500. mu.m, more preferably 0.3 to 300. mu.m, and still more preferably 0.5 to 150. mu.m. When the content is not more than the upper limit of the above range, the hole-forming processability is good and the dielectric characteristics are excellent.

The heat pressing temperature of the fluororesin film and the prepreg or the laminate and the prepreg is preferably not higher than the melting point of the fluororesin F, more preferably 120 to 300 ℃, still more preferably 140 to 240 ℃, and still more preferably 160 to 220 ℃. When the hot pressing temperature is within the above range, the fluorine-containing resin film can be laminated on the object to be laminated or the laminate can be laminated on the object to be laminated with excellent interlayer adhesion.

When the object to be laminated contains a thermoplastic resin, 50 mass% or more of polyimide (such as aromatic polyimide), liquid crystal polyester, PTFE, TFE/PAVE copolymer, TFE/HFP copolymer, or polychlorotrifluoroethylene, or 50 mass% or more of the thermoplastic resin, the hot pressing temperature is preferably 310 to 400 ℃, more preferably 320 to 380 ℃, and still more preferably 330 to 370 ℃. When the hot pressing temperature is within the above range, the fluorine-containing resin film can be laminated on the object to be laminated or the laminate can be laminated on the object to be laminated with excellent interlayer adhesion.

The fluororesin film in the hot-pressed laminate or the layer a of the laminate may contain a filler or reinforcing fibers. The object to be laminated may contain a filler, a reinforcing fiber, and a fluoropolymer F11.

The peel strength at the interface between the fluororesin thin film of the hot-pressed laminate and the object to be laminated or between the laminate and the object to be laminated is preferably 5N/10mm or more, more preferably 7N/10mm or more, and still more preferably 8N/10mm or more.

The relative dielectric constant (20GHz) of the hot-pressed laminate when the thermosetting resin H is used for the layer B is preferably less than 3.6, more preferably 3.55 or less, and particularly preferably 3.20 or less. The lower the relative dielectric constant (20GHz) of the thermocompression bonded laminate, the more excellent transmission efficiency can be obtained when the thermocompression bonded laminate is used for a substrate of a printed circuit board.

When the thermosetting resin H is used for the layer B, the dielectric loss tangent (20GHz) of the hot-pressed laminate is preferably 0.01 or less, more preferably 0.007 or less, and particularly preferably 0.005 or less. The lower the dielectric loss tangent (20GHz) of the hot-pressed laminate, the more excellent transmission efficiency can be obtained when the hot-pressed laminate is used as a substrate for a printed wiring board.

The rate of change of the laminate including the fluororesin thin film is preferably 3% or more, more preferably 5% or more, and even more preferably 10% or more, when the laminate including no fluororesin thin film is 1, from the value of the S parameter (90GHz) obtained in the evaluation of the transmission loss of the hot-pressed laminate. When the hot-pressed laminate is used as a substrate for a printed wiring board, excellent transmission efficiency can be obtained.

When the surface of the fluorine-containing resin thin film containing the fluorine-containing resin F is subjected to surface treatment so that Ra (AFM) becomes 3.0nm or more, the wetting tension of the surface becomes 30 mN/or more. Accordingly, a surface treatment of the fluororesin film containing the fluororesin F to obtain a fluororesin film having a wetting tension of at least one surface in the thickness direction of 30mN/m or more can be performed, and a hot-pressed laminate having excellent interlayer adhesiveness can be similarly produced by bonding an object to be laminated to the surface of the fluororesin film having a wetting tension of 30mN/m or more by hot pressing at a temperature of the melting point of the fluororesin F or less.

[ method for producing printed Circuit Board ]

The manufacturing method of the printed circuit board of the invention is as follows: the method for producing a hot-pressed laminate of the present invention produces a hot-pressed laminate in which layer B is a metal layer, and etches the metal layer to form a pattern circuit, thereby obtaining a printed wiring board. The metal layer may be etched by a known method.

In the method for manufacturing a printed wiring board of the present invention, the metal layer may be etched to form a pattern circuit, an interlayer insulating film may be formed on the pattern circuit, and a pattern circuit may be further formed on the interlayer insulating film. The interlayer insulating film may be formed of the liquid composition. Specifically, for example, the following methods can be cited. The metal layer of the metal laminated plate having an arbitrary laminated structure is etched to form a pattern circuit, and then a liquid composition is applied to the pattern circuit, dried, and heated to form an interlayer insulating film. Next, a metal layer is formed on the interlayer insulating film by vapor deposition or the like, and etching is performed to further form a pattern circuit.

In the manufacture of a printed wiring board, a solder resist layer may be laminated on a pattern circuit. The solder resist layer can be formed of the aforementioned liquid composition, for example. Specifically, the liquid composition may be applied to a pattern circuit, dried, and then heated to form a solder resist layer.

In the production of the printed wiring board, a cover film may be laminated. The cover film is typically composed of a base film and an adhesive layer formed on the surface thereof, and the surface on the adhesive layer side is bonded to the printed circuit board. The fluororesin film of the present invention can be used as the base film of the cover film, for example. Further, an interlayer insulating film (adhesive layer) using the fluorine-containing resin film of the present invention may be formed on a pattern circuit formed by etching a metal layer, and a polyimide film may be laminated as a cover film.

The printed wiring board obtained by the manufacturing method of the present invention is useful as a substrate for electronic devices such as radars, network routers, chassis boards, wireless infrastructures, and the like, a substrate for various sensors for automobiles, and a substrate for engine management sensors, which require high-frequency characteristics, and is particularly suitable for applications aimed at reducing transmission loss in the millimeter wave band.

As described above, in the present invention, the fluorine-containing resin F having excellent heat resistance such as a melting point of 260 to 380 ℃ is used. Further, since ra (afm) of the surface of the layer a of the fluororesin thin film or the laminate is adjusted to 3.0nm or more, excellent interlayer adhesiveness can be obtained even when the object to be laminated is laminated on the surface by hot pressing at a temperature of the melting point of the adhesive fluororesin or less.

In the present invention, the reason why the surface of the layer a of the fluororesin thin film or the laminate having an ra (afm) of 3.0nm or more is excellent in interlayer adhesion to the object to be laminated is not necessarily clear, but is considered as follows. This is considered to be because an anchor effect can be obtained at the adhesion interface when ra (afm) is 3.0nm or more, and the surface area of the fluorine-containing resin film or layer a on the adhesion surface to the object to be laminated is increased, and the density of the adhesive functional groups is increased accordingly.

The same applies to the case where "Ra (AFM)" is 3.0nm or more "is replaced with" Ra (AFM) is 3.0nm or more and rz (AFM) is 80.0nm or more ".