阅读说明：本技术 可挠性半固化片及其应用 (Flexible prepreg and application thereof ) 是由 刘淑芬 洪金贤 于 2019-01-08 设计创作，主要内容包括：本发明提供一种半固化片,是通过将液晶聚合物不织布含浸或涂布热固化性树脂组合物,并干燥经含浸或涂布的液晶聚合物不织布而制得,该热固化性树脂组合物包含：(A)一不饱和单体；(B)一环状烯烃共聚物,该环状烯烃共聚物包含以下重复单元：(B-1)具有如下式(I)结构的重复单元,<Image he="244" wi="571" file="DDA0001939050400000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image> (B-2)具有如下式(II)结构的重复单元,<Image he="276" wi="700" file="DDA0001939050400000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>以及(B-3)具有如下式(III)结构的重复单元,<Image he="299" wi="700" file="DDA0001939050400000013.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image> 式(I)至式(III)中的R<Sup>1</Sup>至R<Sup>22</Sup>、m、n、o及p如本文中所定义,其中以重复单元(B-1)、(B-2)及(B-3)的总莫耳数计,该重复单元(B-2)的量为19莫耳％至36莫耳％；以及该环状烯烃共聚物(B)对该不饱和单体(A)的重量比为0.5至7。(The invention provides a prepreg which is prepared by impregnating or coating a liquid crystal polymer non-woven fabric with a thermosetting resin composition, drying the resin composition and curing the resin compositionImpregnated or coated liquid crystal polymer nonwoven fabric, the thermosetting resin composition comprising: (A) an unsaturated monomer; (B) a cyclic olefin copolymer comprising the following repeating units: (B-1) a repeating unit having a structure represented by the following formula (I), (B-2) a repeating unit having the structure of the following formula (II), and (B-3) a repeating unit having a structure represented by the following formula (III), r in the formulae (I) to (III) 1 To R 22 M, n, o and p are as defined herein, wherein the amount of the repeating unit (B-2) is 19 to 36 mol% based on the total mol of the repeating units (B-1), (B-2) and (B-3); and the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (A) is 0.5 to 7.)

1. A prepreg obtained by impregnating or coating a liquid crystal polymer nonwoven fabric with a thermosetting resin composition and drying the impregnated or coated liquid crystal polymer nonwoven fabric, wherein the thermosetting resin composition comprises:

(A) an unsaturated monomer; and

(B) a cyclic olefin copolymer comprising the following repeating units:

(B-1) a repeating unit having a structure represented by the following formula (I),

(B-2) a repeating unit having the structure of the following formula (II),

and

(B-3) a repeating unit having the structure of the following formula (III),

wherein the content of the first and second substances,

R¹is H or C₁To C₂₉The straight chain or branched hydrocarbon group of (1);

R²to R²¹Each independently of the other being H, halogen, C₁To C₂₀Alkyl of (C)₁To C₂₀Halogenated alkyl group of C₃To C₁₅Cycloalkyl or C₆To C₂₀An aromatic hydrocarbon group of (1);

R¹⁸to R²¹May combine with each other to form a monocyclic or polycyclic ring;

R²²is H or C₁To C₁₀Alkyl groups of (a);

m and n are each independently 0 or 1;

o is 0 or a positive integer;

p is an integer of 0 to 10; and

in formula (III), R is 0 for both m and o¹⁰To R¹³And R¹⁸To R²¹At least one of them is a substituent other than H,

wherein the amount of the repeating unit (B-2) is 19 to 36 mol% based on the total mol of the repeating units (B-1), (B-2) and (B-3); and

wherein the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (A) is 0.5 to 7.

2. The prepreg according to claim 1, wherein the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (A) is 0.6 to 2.4.

3. The prepreg according to claim 1, wherein the unsaturated monomer (A) is selected from the group consisting of: alkenyl aromatic monomers, allyl-containing monomers, acryl-containing monomers, vinyl ethers, maleimides, and combinations thereof.

4. A prepreg according to claim 3, wherein the allyl-containing monomer comprises an organic compound having at least one allyl group.

5. The prepreg of claim 4, wherein the allyl-containing monomer is selected from the group consisting of: diallyl phthalate, diallyl isophthalate, triallyl mellitate, triallyl benzenetricarboxylate, triallylbenzene, triallyl cyanurate, triallyl isocyanurate, triallylamine, and combinations thereof.

6. The prepreg according to claim 1, wherein R is¹Is H or C₁To C₆Alkyl group of (1).

7. The prepreg according to claim 1, wherein the repeating unit (B-2) is formed by addition copolymerization of a cyclic nonconjugated diene monomer selected from the group consisting of:

and combinations thereof.

8. The prepreg according to claim 1, wherein the content of the repeating unit (B-2) is 20 to 33 mol% based on the total mol of the repeating units (B-1), (B-2) and (B-3).

9. The prepreg according to claim 1, wherein the thermally curable resin composition further comprises one or more selected from the group consisting of: the flame retardant is prepared from a flame retardant, a catalyst, a filler, a curing accelerator, a dispersing agent, a toughening agent, a viscosity regulator, a thixotropic agent, a defoaming agent, a leveling agent, a surface treating agent, a stabilizer and an antioxidant.

10. The prepreg according to claim 9, wherein the flame retardant is selected from the group consisting of: phosphorus-containing flame retardants, bromine-containing flame retardants, and combinations thereof.

11. The prepreg of claim 9, wherein the catalyst is selected from the group consisting of dicumyl peroxide, α' -bis (tertiary butyl peroxy) dicumyl peroxide, dibenzoyl peroxide, and combinations thereof.

12. The prepreg according to claim 1, wherein the liquid crystal polymer nonwoven fabric comprises liquid crystal polyester fibers having an average diameter of 0.6 to 20 μm and an elongation in the Machine Direction (MD) and the Cross Direction (CD) of 1 to 8% independently of each other.

13. The prepreg according to claim 12, wherein the liquid crystal polyester fiber has a fiber of a liquid crystal polyester of one or more of the following repeating units (1) to (11):

(1)

(2)

(3)

(4)wherein X, X ', Y and Y' are each independently H, Cl, Br or methyl, Z is

(5)

(6)

(7)

(8)

(9)

(10) And

(11)

14. the prepreg according to claim 12, wherein the liquid crystal polyester fiber has a fiber of a liquid crystal polyester having repeating units of the following formulae (IV) and (V) and the content of the repeating units of the formulae (IV) and (V) is at least 65 mol% based on 100 mol% of the total amount of the repeating units of the liquid crystal polyester,

15. a metal-foil laminate produced by laminating the prepreg according to any one of claims 1 to 14 with a metal foil.

16. A printed circuit board produced from the laminate of claim 15.

Technical Field

The present invention relates to a flexible prepreg (prepreg), and more particularly, to a flexible prepreg obtained by impregnating or coating a liquid crystal polymer nonwoven fabric with a thermosetting resin composition and drying the impregnated or coated liquid crystal polymer nonwoven fabric, and a flexible metal foil laminate (laminate) and a printed circuit board using the same.

Background

A Printed Circuit Board (PCB) can be used as a substrate of an electronic device, and can carry a plurality of electronic components electrically connected to each other, so as to provide a stable circuit working environment. The printed circuit board is mainly made of a laminate formed by alternately laminating dielectric layers and conductive layers. Generally, a printed circuit board can be prepared by the following method.

First, a reinforcing material (e.g., a glass cloth) is impregnated with a resin (e.g., an epoxy resin), and the resin-impregnated reinforcing material is cured to a semi-cured state (i.e., a B-stage) to obtain a prepreg as a dielectric layer. Subsequently, a predetermined number of dielectric layers (prepregs) are stacked, and a conductive layer (e.g., a metal foil) is stacked on at least one outer side of the stacked dielectric layers to provide a stack, and then a hot pressing operation (i.e., a C-stage) is performed on the stack to obtain a laminate. The conductive layer on the surface of the laminate is etched to form a predetermined circuit pattern (circuit pattern). Finally, a plurality of holes are punched in the etched laminate, and conductive materials are plated in the holes to form vias (vias), thereby completing the fabrication of the printed circuit board.

With the miniaturization of electronic devices, printed circuit boards also have to meet the demands for thinner, higher density, and high frequency and high speed transmission. In view of the above, many fluororesin substrates or polyphenylene ether resin substrates are currently used to meet the demand for high-frequency and high-speed transmission. For example, JP 61-287939 discloses a laminate obtained by laminating and molding a resin-impregnated base material formed by impregnating a resin composition containing polyphenylene ether and a crosslinkable polymer into the base material and then irradiating the resin-impregnated base material with radiation. JP8-245872 discloses a curable composite material comprising a reaction product of polyphenylene ether and an unsaturated carboxylic acid or anhydride, triallyl cyanurate and/or triallyl isocyanurate, a peroxide, a flame retardant, antimony oxide and a substrate. However, in the above technical solution, the glass fiber substrate is used, and the prepared material has no flexibility.

US 2018270945 also discloses a multilayer printed wiring board in which an insulating layer (i.e., a dielectric layer) and a conductive layer are stacked, wherein the insulating layer includes a liquid crystal polymer resin layer which is a film made of a liquid crystal polymer resin. Although this makes the multilayer printed wiring board flexible, it also causes poor adhesion between the insulating layer and the conductive layer, which leads to a decrease in reliability of the multilayer printed wiring board.

Disclosure of Invention

In view of the above technical problems, the present invention provides a prepreg using a liquid crystal polymer nonwoven fabric and a thermosetting resin composition, wherein the prepreg has flexibility and can be formed into three-dimensional wiring according to a spatially-changed shape, so that the wiring density of a system can be increased and the product volume can be reduced. In addition, the flexible metal foil laminated plate prepared by using the prepreg has the characteristics of low dielectric constant (Dk) value, low dielectric loss factor (Df), high heat resistance, high adhesiveness between a conductive layer and a dielectric layer and the like.

Accordingly, an object of the present invention is to provide a prepreg obtained by impregnating or coating a liquid crystal polymer nonwoven fabric with a thermosetting resin composition, and drying the impregnated or coated liquid crystal polymer nonwoven fabric, wherein the thermosetting resin composition comprises:

(A) an unsaturated monomer; and

(B) a cyclic olefin copolymer comprising the following repeating units:

(B-1) a repeating unit having a structure represented by the following formula (I),

(B-2) a repeating unit having the structure of the following formula (II),

and

(B-3) a repeating unit having the structure of the following formula (III),

wherein the content of the first and second substances,

R¹is H or C₁To C₂₉A straight-chain or branched hydrocarbon group of (2), more specifically, R¹Can be H or C₁To C₆Alkyl groups of (a);

R²to R²¹Each independently of the other being H, halogen, C₁To C₂₀Alkyl of (C)₁To C₂₀Halogenated alkyl group of C₃To C₁₅Cycloalkyl or C₆To C₂₀An aromatic hydrocarbon group of (1);

R¹⁸to R²¹May combine with each other to form a monocyclic or polycyclic ring;

R²²is H or C₁To C₁₀Alkyl groups of (a);

m and n are each independently 0 or 1;

o is 0 or a positive integer;

p is an integer of 0 to 10; and

in formula (III), R is 0 for both m and o¹⁰To R¹³And R¹⁸To R²¹At least one of them is a substituent other than H,

wherein the amount of the repeating unit (B-2) is 19 to 36 mol%, and preferably 20 to 33 mol%, based on the total mol of the repeating units (B-1), (B-2) and (B-3); and

wherein the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (A) is 0.5 to 7, more specifically, the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (A) may be 0.6 to 2.4.

In some embodiments of the invention, the unsaturated monomer (a) is selected from the group consisting of: alkenyl aromatic monomers, allyl-containing monomers, acryl-containing monomers, vinyl ethers, maleimides, and combinations thereof.

In some embodiments of the invention, the allyl-containing monomer comprises an organic compound having at least one allyl group.

In some embodiments of the invention, the allyl-containing monomer is selected from the group consisting of: diallyl phthalate, diallyl isophthalate, triallyl mellitate, triallyl trimesate, triallylbenzenes, triallyl cyanurate, triallyl isocyanurate, triallylamines, and combinations thereof.

In some embodiments of the present invention, the repeating unit (B-2) is formed by addition copolymerization of a cyclic non-conjugated diene monomer selected from the group consisting of:

and combinations thereof.

In some embodiments of the present invention, the thermally curable resin composition may further comprise one or more selected from the group consisting of flame retardants, catalysts, fillers, curing accelerators (curing accelerators), dispersants, toughening agents, viscosity modifiers, thixotropic agents (thixotropic agents), defoamers, leveling agents (leveling agents), surface treatment agents, stabilizers, and antioxidants.

In some embodiments of the invention, the liquid crystalline polymer nonwoven fabric comprises liquid crystalline polyester fibers having an average diameter of 0.6 to 20 microns and a Machine Direction (MD) and Cross Direction (CD) elongation of 1 to 8% each independently. The liquid crystal polyester fiber may be a fiber of a liquid crystal polyester having one or more of the following repeating units (1) to (11):

(1)and

(2)and

(3)

(4)andwherein X, X ', Y and Y' are each independently H, Cl, Br or methyl, Z is Or

(5)And

(6)and

(7)and

(8)and

(9)and

(10)and and

(11)and

in some embodiments of the present invention, the liquid crystal polyester fiber has a fiber of a liquid crystal polyester having repeating units of the following formulae (IV) and (V), and the content of the repeating units of the formulae (IV) and (V) is at least 65 mol% based on 100 mol% of the total amount of the repeating units of the liquid crystal polyester,

another object of the present invention is to provide a metal-foil laminate obtained by laminating the prepreg and the metal foil as described above.

It is still another object of the present invention to provide a printed circuit board made from the laminate as described above.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, some embodiments accompanied with figures are described in detail below.

Detailed Description

Some specific embodiments according to the present invention will be specifically described below; the invention may, however, be embodied in many different forms without departing from the spirit thereof, and the scope of the invention should not be construed as limited to the specific embodiments set forth herein.

As used in this specification (and particularly in the claims), the terms "a," "an," "the," and the like are to be understood to encompass both the singular and the plural, unless the context clearly dictates otherwise.

Unless otherwise indicated herein, the ingredients contained in a solution, mixture or composition are described in this specification in terms of solids (dry weight), i.e., the weight of the solvent not included.

Unless otherwise indicated herein (especially in the claims), the terms "group" and "groups" include, but are not limited to, alkyl, alkenyl, alkynyl, aromatic, and the like, including forms having a linear, branched, cyclic, or combinations thereof.

The prepreg of the present invention is prepared by impregnating or coating a liquid crystal polymer nonwoven fabric with a thermosetting resin composition, and drying the impregnated or coated liquid crystal polymer nonwoven fabric. The components and preparation of the prepregs of the present invention are described in detail below.

1. Thermosetting resin composition

In the prepreg of the present invention, the thermosetting resin composition contains essential components such as the unsaturated monomer (a) and the cyclic olefin copolymer (B), and other optional components as required. The details of each component are as follows.

1.1. Unsaturated monomer (A)

In the thermosetting resin composition, the unsaturated monomer (A) means a polymerizable monomer containing a carbon-carbon double bond and being reactive with other unsaturated olefin. Examples of unsaturated monomers include, but are not limited to: alkenyl aromatic monomers, allyl-containing monomers, acryl-containing monomers, vinyl ethers, maleimides, and combinations thereof.

1.1.1. Alkenyl aromatic monomer

The alkenyl aromatic monomer may, for example, be a monomer represented by the following formula:

in the above formula, R³¹Each independently is H or C₁To C₁₈A hydrocarbyl group; r³²Each independently is H, C₁To C₁₂Alkyl radical, C₁To C₁₂Alkoxy or C₆To C₁₈An aryl group; u is 1 to 4; and v is 0 to 5. C₁To C₁₈Hydrocarbyl groups include, but are not limited to, C₁To C₁₂Alkyl radical, C₂To C₁₂Alkenyl radical, C₂To C₁₂Alkynyl and C₆To C₁₈And (4) an aryl group. C₁To C₁₂Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, n-pentyl, isopentyl, tertiary pentyl, neopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, n-nonyl, isononyl, n-decyl, isodecyl, undecyl, and dodecyl. C₂To C₁₂Examples of alkenyl groups include, but are not limited to, ethenyl, propenyl, allyl, n-butenyl, isobutenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, butadienyl, pentadienyl, and hexadienyl. C₂To C₁₂Examples of alkynyl groups include, but are not limited to, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, and decynyl. C₁To C₁₂Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy. C₆To C₁₈Examples of aryl groups include, but are not limited to, phenyl, biphenyl, naphthyl, anthryl, phenanthryl, indenyl, fluorenyl, and anthracenyl.

Examples of alkenyl aromatic monomers include, but are not limited to, styrene, Divinylbenzene (DVB), divinylnaphthalene, divinylbiphenyl, diisopropenylbenzene, and combinations thereof, examples of styrene include, but are not limited to, α -methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-tertiarybutylstyrene, 3-tertiarybutylstyrene, 4-tertiarybutylstyrene, and styrenes containing 1 to 5 halogen substituents on the benzene ring examples of divinylbenzene include, but are not limited to, 1, 3-divinylbenzene and 1, 4-divinylbenzene examples of diisopropenylbenzene include, but are not limited to, 1, 3-diisopropenylbenzene and 1, 4-diisopropenylbenzene.

1.1.2. Allyl group-containing monomer

The allyl-containing monomer is a monomer containing at least one allyl group (-CH)₂-CH＝CH₂) Organic compounds preferably containing at least two allyl groups, more preferably at least three allyl groups. Examples of allyl-containing monomers include, but are not limited to, diallyl phthalate, diallyl isophthalate, triallyl mellitate, triallyl trimesate, triallylbenzene, triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), and triallylamine. The foregoing compounds may be used alone or in any combination. In the examples that follow, triallyl isocyanurate (TAIC) was used.

1.1.3. Monomer containing acryloyl group

The acryloyl group containing monomer may be a compound comprising at least one acryloyl moiety having the structure, preferably at least two such acryloyl moieties, and more preferably at least three such acryloyl moieties:

in the acryloyl moiety, R³³To R³⁵Each independently is H, C₁To C₁₂Hydrocarbyl radical, C₂To C₁₈Hydrocarbonoxycarbonyl, cyano (-C ≡ N), formyl (-CHO), carboxyl (-C (═ O) OH), imidate group (-C (═ NH) OH), or thiocarboxylic (-C (═ O) SH). C₁To C₁₂Hydrocarbyl groups include, but are not limited to, C₁To C₁₂Alkyl radical, C₂To C₁₂Alkenyl radical, C₂To C₁₂Alkynyl and C₆To C₁₂And (4) an aryl group. Related to C₁To C₁₂Alkyl radical, C₂To C₁₂Alkenyl radical、C₂To C₁₂Alkynyl and C₆To C₁₂Examples of aryl groups, as mentioned above, are not further described herein. C₂To C₁₈Hydrocarbyloxycarbonyl radicals include but are not limited to C₂To C₁₂Alkoxycarbonyl and C₇To C₁₈An aryloxycarbonyl group. C₂To C₁₂Alkoxycarbonyl includes, but is not limited to, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, hexoxycarbonyl, heptoxycarbonyl, octoxycarbonyl, nonyloxycarbonyl, and decyloxycarbonyl. C₇To C₁₈Aryloxycarbonyl groups include, but are not limited to, phenoxycarbonyl and naphthyloxycarbonyl.

Examples of the acryl-containing monomer include, but are not limited to, trimethylolpropane tri (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, cyclohexane dimethanol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate (DCP), butanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, isoborneol (meth) acrylate, methyl (meth) acrylate, methacryloxypropyl trimethoxysilane, and ethoxylated (2) bisphenol A di (meth) acrylate, wherein the number following the phrase "ethoxylation" refers to the average number of ethoxy groups in the ethoxylate chain per oxygen attached to bisphenol A. The foregoing compounds may be used alone or in any combination. In the examples that follow, Dicidol di (meth) acrylate (DCP) was used.

1.1.4. Vinyl ethers

Vinyl ethers are those containing at least one vinyl ether group (-O-CH ═ CH)₂) Preferably, compounds containing at least two vinyl ether groups, more preferably at least three vinyl ether groups. Examples of vinyl ethers include, but are not limited to, 1, 2-ethylene glycol divinyl ether, 1, 3-propylene glycol divinyl ether, 1, 4-butanediol divinyl ether, triethylene glycol divinyl ether, 1, 4-cyclohexanedimethanol divinyl ether, ethyl vinyl ether, n-butyl vinyl etherButyl vinyl ether, dodecyl vinyl ether and 2-chloroethyl vinyl ether. The foregoing compounds may be used alone or in any combination.

1.1.5. Maleimide

Maleimide is a compound containing at least one maleimide group as shown below:

examples of the maleimide include, but are not limited to, N-phenylmaleimide, 1, 4-phenylene-bismaleimide- α '-bismaleimide, 2-bis (4-phenoxyphenyl) -N, N' -bismaleimide, N '-phenylenebismaleimide, N' -hexamethylenebismaleimide, N '-biphenylmethane bismaleimide, N' -oxy-di-p-phenylenebismaleimide, N '-4,4' -benzophenone bismaleimide, N '-p-biphenylsulfone bismaleimide, N' - (3,3 '-dimethyl) methylene-di-p-phenylenebismaleimide, poly (phenylmethylene) polymaleimide, bis (4-phenoxyphenyl) sulfone-N, N' -bismaleimide, 1, 4-bis (4-phenoxy) benzene-N, N '-bismaleimide, 1, 3' -bis (4-phenoxyphenyl) imide, and combinations of any of the foregoing may be used alone or in combination.

According to the present invention, the content of the unsaturated monomer (a) may be 12 to 70% by weight, preferably 15 to 60% by weight, more preferably 18 to 50% by weight, for example 19, 20, 22, 25, 28, 30, 32, 35, 38, 40, 42, 45, 48 or 49% by weight, based on the total weight of the resin composition.

1.2. Cyclic olefin copolymer (B)

The cyclic olefin copolymer (B) is another essential component of the thermosetting resin composition. The cyclic olefin copolymer (B) has a crosslinkable group and comprises a repeating unit (B-1) having a structure represented by the following formula (I), a repeating unit (B-2) having a structure represented by the following formula (II) and a repeating unit (B-3) having a structure represented by the following formula (III).

In formulae (I) to (III), R¹Is H or C₁To C₂₉Is a straight-chain or branched hydrocarbon group, and is preferably H or C₁To C₂₉An alkyl group; r²To R²¹Each independently of the other being H, halogen, C₁To C₂₀Alkyl radical, C₁To C₂₀Halogenated alkyl radicals, C₃To C₁₅Cycloalkyl or C₆To C₂₀Aromatic hydrocarbon radical, and R¹⁸To R²¹May combine with each other to form a monocyclic or polycyclic ring; r²²Is H or C₁To C₁₀An alkyl group; m and n are each independently 0 or 1; o is 0 or a positive integer, preferably an integer of 0 to 50, and more preferably an integer of 0 to 20; p is an integer of 0 to 10; and in formula (III), R is 0 when m and o are both¹⁰To R¹³And R¹⁸To R²¹At least one of them is a substituent other than H.

The repeating unit (B-1) having the structure of formula (I) is formed by addition copolymerization of one or more monomers having the structure of formula (I-1) below.

In the formula (I-1), R¹Is H or C₁To C₂₉The straight-chain or branched hydrocarbon group of (2) is preferably H or C₁To C₂₉Linear or branched alkyl ofAnd more preferably is H or C₁To C₆Examples of the linear or branched alkyl group in (b) include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a tertiary butyl group, a n-pentyl group, an isopentyl group, a tertiary pentyl group, a neopentyl group, a n-hexyl group and an isohexyl group.

Examples of the monomer having the structure of formula (I-1) include, but are not limited to, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-hexene, 4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene. In the following examples, the repeating unit (B-1) having the structure of formula (I) is formed by addition copolymerization of ethylene.

The repeating unit (B-2) having the structure of the formula (II) is formed by addition copolymerization of one or more cyclic nonconjugated diene monomers having the structure of the following formula (II-1).

In the formula (II-1), R²To R¹⁹Can be the same or different and can be respectively and independently H, halogen, C₁To C₂₀Alkyl radical, C₁To C₂₀Halogenated alkyl radicals, C₃To C₁₅Cycloalkyl or C₆To C₂₀Aryl, wherein R¹⁸And R¹⁹May combine with each other to form a monocyclic or polycyclic ring; r²²Is H or C₁To C₁₀An alkyl group; m and n are each independently 0 or 1; o is 0 or a positive integer, preferably an integer of 0 to 50, and more preferably an integer of 0 to 20; and p is an integer of 0 to 10. Preferably, R²To R¹⁹Is H, C₁To C₁₀Alkyl radical, C₃To C₈Cycloalkyl or C₆To C₁₂An aryl group; r²²Is H or C₁To C₆An alkyl group; and o is 0, 1 or 2. Related to C₁To C₁₀Alkyl and C₆To C₁₂Examples of aryl groups are as hereinbefore described,are not described in detail herein. C₃To C₈Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.

Examples of cyclic non-conjugated diene monomers having the structure of formula (II-1) include, but are not limited to:

andand the respective monomers may be used alone or in any combination. In the examples which follow, the recurring unit (B-2) having the structure of formula (II) is prepared from 5-vinyl-2-norborneneThrough addition copolymerization.

The repeating unit (B-3) having the structure of the formula (III) is formed by addition copolymerization of one or more cyclic olefin monomers having the structure of the following formula (III-1).

In the formula (III-1), R²To R¹⁹As defined hereinbefore, R²⁰And R²¹Is as defined for R²To R¹⁹In which R is¹⁸To R²¹May combine with each other to form a monocyclic or polycyclic ring; m and n are each independently 0 or 1; and o is 0 or a positive integer, preferably an integer of 0 to 50, and more preferably an integer of 0 to 20.

Examples of cyclic olefin monomers having the structure of formula (III-1) include, but are not limited to, bicyclo [2.2.1]-2-heptene (norbornene,) And tetracyclo [4.4.0.1^2,5.1^7,10]-3-dodecene (tetracyclododecene,). In the examples which follow, the repeating unit (B-3) having the structure of formula (III) is represented by tetracyclo [4.4.0.1^2,5.1^7,10]-3-dodecene is formed by addition copolymerization.

In the cyclic olefin copolymer (B), the content of the repeating unit (B-2) is from 19 to 36 mol%, preferably from 20 to 33 mol%, and more preferably from 25 to 30 mol%, for example, 26, 27, 28 or 29 mol%, based on the total mol of the repeating units (B-1), (B-2) and (B-3). When the amount of the repeating unit (B-2) is within the above-specified range, the thermosetting resin composition can provide stable dielectric characteristics and excellent heat resistance over a long period of time, and can achieve an excellent balance between mechanical characteristics and dielectric characteristics.

Further, in the cyclic olefin copolymer (B), the content of the repeating unit (B-3) is from 0.1 to 100 mol%, preferably from 0.1 to 50 mol%, more preferably from 1 to 20 mol%, for example, 2 to 3, 5, 7, 9, 10, 12, 13, 15, 17 or 19 mol%, based on the total mol of the repeating units (B-1) and (B-2). When the amount of the repeating unit (B-3) is within the aforementioned specified range, the cyclic olefin copolymer (B) can maintain a suitable elastic modulus, and the crosslinking reaction thereof can be easily controlled.

The cyclic olefin copolymer (B) may contain, in addition to the above-mentioned repeating units (B-1), (B-2) and (B-3), a repeating unit formed by addition copolymerization of another cyclic olefin monomer and/or a chain polyene monomer. The other cyclic olefin monomers do not include cyclic non-conjugated diene monomers having the structure of formula (II-1) and cyclic olefin monomers having the structure of formula (III-1).

As a detailed preparation method of the cyclic olefin copolymer (B), reference is made to the contents described in U.S. Pat. No. 4, 9,206,278, 2, which is incorporated herein by reference in its entirety.

In the prepreg of the present invention, the content of the cyclic olefin copolymer (B) may be 30 wt% to 88 wt%, preferably 40 wt% to 85 wt%, more preferably 50 wt% to 82 wt%, for example 51 wt%, 53 wt%, 55 wt%, 57 wt%, 60 wt%, 63 wt%, 65 wt%, 67 wt%, 70 wt%, 73 wt%, 75 wt%, 77 wt%, or 80 wt%, based on the total weight of the thermosetting resin composition.

In addition, in the prepreg of the present invention, the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (a) is in a specific range, so that the resulting metal foil laminate has excellent room-temperature peel strength and heat resistance. Specifically, the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (A) is 0.5 to 7, preferably 0.6 to 2.4, for example, 0.7, 0.8, 0.9, 1, 1.2, 1.3, 1.5, 1.7, 1.8, 2.0, 2.1, 2.2 or 2.3.

1.3. Optional ingredients

The thermosetting resin composition used for preparing the prepreg of the present invention may optionally contain other components, such as additives existing in the art, to improve the physicochemical properties of a laminate prepared by the thermosetting resin composition or to improve the processability of the thermosetting resin composition during the manufacturing process. Examples of such prior additives include, but are not limited to: flame retardant, catalyst, filler, curing accelerator, dispersant, toughening agent, viscosity regulator, thixotropic agent, defoaming agent, leveling agent, surface treating agent, stabilizer, antioxidant and the like. The additives may be used alone or in any combination thereof, and the amount of each additive may be adjusted as needed by one of ordinary skill in the art in view of the contents of the present specification without particular limitation according to the general knowledge thereof. The following is exemplified.

1.3.1. Flame retardant

The thermosetting resin composition may optionally contain a flame retardant, thereby improving the flame retardancy of the electronic material produced. Examples of flame retardants include, but are not limited to, phosphorus-containing flame retardants and bromine-containing flame retardants. Examples of phosphorus-containing flame retardants include, but are not limited to, phosphates, phosphazenes, ammonium polyphosphates, melamine phosphates, melamine cyanurates, metal hypophosphites, and combinations thereof. Examples of phosphazenes include, but are not limited to, cyclic phosphazene compounds and linear phosphazene compounds. Examples of cyclic phosphazene compounds include, but are not limited to, hexaphenoxycyclotriphosphazene. Examples of hypophosphorous acid metal salts include, but are not limited to, metal salt compounds having the formula:

wherein each R is independently C₁To C₅An alkyl group; m^a+Is a metal ion selected from the group consisting of: al (Al)³⁺、Zn²⁺、Ca²⁺、Ti⁴⁺、Mg²⁺、Sr²⁺、Ba²⁺、K⁺And Cu²⁺(ii) a And a is an integer of 1 to 4.

Examples of bromine-containing flame retardants include, but are not limited to, tetrabromobisphenol A (tetrabromobisphenol A), decabromodiphenyl oxide (decabromodiphenyl oxide), decabrominated diphenylethane (decabrominated diphenylethane), 1,2-bis (tribromophenyl) ethane (1,2-bis (tribromophenyl) ethane), brominated epoxy oligomer (brominated epoxy oligomer), octabromotrimethylphenyl indene (octabromotrimethylphenylindole), bis (2,3-dibromopropyl ether) (bis (2,3-dibromopropyl ether)), tris (tribromophenyl) triazine (tris (brominated) triazine), brominated aliphatic hydrocarbons (brominated aliphatic hydrocarbons), and brominated aromatic hydrocarbons (brominated aromatic hydrocarbons). The foregoing flame retardants may be used alone or in any combination.

1.3.2. Catalyst and process for preparing same

Examples of the organic Peroxide include, but are not limited to, dicumyl Peroxide (DCP), α '-bis (t-butylperoxy) diisopropylbenzene (α' -bis (t-butylperoxy) diisopropy-lene benzene, PERBUTY L P) and dibenzoyl Peroxide (BPO). The foregoing catalysts may be used alone or in any combination.

1.3.3. Filler material

Examples of fillers include, but are not limited to: silica (e.g., hollow silica), alumina, magnesia, magnesium hydroxide, calcium carbonate, talc, clay, aluminum nitride, boron nitride, aluminum hydroxide, aluminum silicon carbide, sodium carbonate, titanium dioxide, zinc oxide, zirconium oxide, quartz, diamond-like, graphite, calcined kaolin, kaolin clay, mica, hydrotalcite, Polytetrafluoroethylene (PTFE) powder, glass beads, ceramic whiskers, carbon nanotubes, nano-sized inorganic powders, and combinations thereof.

1.3.4. Curing accelerator

The curing accelerator means an ingredient that can accelerate curing and lower the curing reaction temperature of the resin. Suitable cure accelerators include, but are not limited to, tertiary amines, quaternary ammonium, imidazoles, and pyridines. Examples of imidazoles include, but are not limited to, 2-methylimidazole, 2-ethyl-4-methylimidazole (2E4MZ), and 2-phenylimidazole. Examples of pyridines include, but are not limited to, 2, 3-diaminopyridine, 2, 5-diaminopyridine, 2, 6-diaminopyridine, 4-dimethylaminopyridine, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, and 2-amino-3-nitropyridine. The aforementioned curing accelerators may be used alone or in any combination.

2. Preparation of thermosetting resin composition

The thermosetting resin composition can be prepared by uniformly mixing the respective components of the thermosetting resin composition, including the unsaturated monomer (a), the cyclic olefin copolymer (B) and other optional additives, with a mixer and dissolving or dispersing the mixture in a solvent to prepare a varnish form for subsequent processing and use. The solvent may be any inert solvent that can dissolve or disperse the components of the thermosetting resin composition but does not react with the components. For example, the solvent that can be used to dissolve or disperse the components of the thermosetting resin composition includes, but is not limited to: toluene, gamma-butyrolactone, methyl ethyl ketone, cyclohexanone, butanone, acetone, xylene, methyl isobutyl ketone, N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), and combinations thereof. The amount of the solvent used is not particularly limited, and may be in principle any amount that can uniformly dissolve or disperse the components of the thermosetting resin composition. In some embodiments of the invention, toluene is used as the solvent.

3. Liquid crystal polymer non-woven fabric

In the prepreg of the present invention, the liquid crystal polymer nonwoven fabric includes liquid crystal polyester fibers. The liquid crystal polyester fiber is a polymer fiber obtained by polymerizing an aromatic diol, an aromatic dicarboxylic acid, an aromatic hydroxycarboxylic acid, or the like, and has optical anisotropy (liquid crystallinity) in a melt phase, which can be easily recognized by raising the temperature of a sample on a hot stage in a nitrogen atmosphere and observing transmitted light. In some embodiments of the present invention, the liquid crystal polyester fiber has a fiber of a liquid crystal polyester of one or more of the following repeating units (1) to (11):

(1)and

(2)and

(3)

(4)andwherein X, X ', Y and Y' are each independently H, Cl, Br or methyl, Z is Or

(5)And

(6)and

(7)and

(8)and

(9)and

(10)and and

(11)and

the liquid-crystalline polyester fiber is preferably a fiber of an aromatic polyester containing at least 65 mol% of the repeating units represented by the following formulae (IV) and (V) based on the total mol of the repeating units, more preferably a fiber of an aromatic polyester containing 4 to 45 mol% of the repeating units represented by the formula (V) based on the total mol of the repeating units.

In addition, the liquid-crystalline polyesters used according to the invention may contain other polymers or additives without substantial reduction in strength.

The liquid crystal polymer non-woven fabric is melt-blown non-woven fabric (melt-blown non-woven fabric), and the preparation method comprises the following steps: the liquid crystalline polyester is melt-spun from a nozzle while the molten liquid crystalline polyester is blown off in the form of fine fibers by a high-temperature high-speed gas and collected on a suction collection surface (e.g., a wire mesh) to form a web, which is subjected to calendering and heat treatment to obtain a nonwoven fabric. The calendering is carried out at a surface temperature of the nonwoven fabric of between 90 ℃ and the melting point temperature of the molten liquid crystalline polyester and at a linear pressure of between 50 kg/cm and 200 kg/cm.

The average diameter of the fibers collected by the meltblowing process on the suction collection surface depends on the nozzle diameter, the discharge volume and the gas flow rate. The liquid crystal polyester fiber has an average diameter of 0.6 to 20 micrometers, preferably 1 to 15 micrometers, and more preferably 60% or more of the fibers have an average diameter of 1 to 10 micrometers. The liquid crystal polyester fiber has elongation in the Machine Direction (MD) and the Cross Direction (CD) of 1 to 8 percent, and has strength, flexibility and air permeability. The average fiber diameter is an average value obtained by taking a magnified photograph of the nonwoven fabric using a scanning electron microscope and measuring the diameter of any 100 fibers. The detailed preparation method of the liquid crystal polymer nonwoven fabric can be referred to the content described in JP 4429501, which is incorporated herein by reference in its entirety.

4. Preparation of prepregs

The prepreg of the present invention can be produced by impregnating or coating a liquid crystal polymer nonwoven fabric with the thermosetting resin composition and drying the same, or by forming a film from the thermosetting resin composition and bonding the film to the liquid crystal polymer nonwoven fabric by hot pressing. In some embodiments of the present invention, a prepreg in a semi-cured state is prepared by impregnating or coating a liquid crystal polymer nonwoven fabric with a thermosetting resin composition and drying it by heating at 160 ℃ for 2 to 15 minutes (B-stage) using VECRUS liquid crystal polymer nonwoven fabric available from Korea (Kuraray) Co.

5. Metal foil laminate and printed wiring board

The invention also provides a metal foil laminated plate prepared from the prepreg, which comprises a dielectric layer and a conductive layer, wherein the dielectric layer is formed by laminating one or more layers of the prepregs, a metal foil (such as a copper foil) is laminated on at least one outer side surface of the dielectric layer formed by laminating the prepregs to provide a laminated object, and the laminated object is subjected to hot pressing operation to obtain the metal foil laminated plate.

In addition, a printed circuit board may be manufactured by further patterning the conductive layer of the metal foil laminate, and examples of the existing patterning method include, but are not limited to, etching.

6. Examples of the embodiments

6.1. Description of the measurement method

The invention will now be further illustrated by the following specific embodiments, in which the measuring instruments and methods used are as follows:

[ measurement of dielectric constant (Dk) and dielectric dissipation factor (Df) ]

The dielectric constant (Dk) and dielectric dissipation factor (Df) of the metal foil laminate were calculated according to the IPC-TM-6502.5.5.13 specification at an operating frequency of 10 gigahertz (GHz).

[ Peel Strength test ]

The peel strength is used to show the strength of adhesion between the metal foil conductive layer and the dielectric layer. In this test, the copper foil with a width of 1/8 inches was vertically peeled from the surface of the board, and the strength of the adhesion was expressed by the amount of force required. Peel strength is reported in pounds force per inch (lbf/in).

[ flexibility test ]

The flexibility test was performed by recording the number of MIT deflections according to the MIT test method (JIS P8815 specification) as "○" if the number of MIT deflections is greater than 100, as "△" if the number of MIT deflections is between 50 and 100, and as "hot" if the number of MIT deflections is less than 50.

[ test for Heat resistance after moisture absorption ]

The heat resistance after moisture absorption was measured in accordance with JIS C5012, and the heat resistance of the metal foil laminate after 120 hours at 60 ℃ and 60% Relative Humidity (RH) was evaluated, and after the metal foil laminate was subjected to float welding in a solder bath at 288 ℃ for 60 seconds, it was observed with a visual and optical microscope (x5 times or more) whether or not the metal foil laminate after the float welding test showed scars (measling) or swelling, and the like, and if no scars or swelling were observed, it was recorded as "○", and if they were observed, it was recorded as "x".

6.2. List of raw material information for examples and comparative examples:

6.3. preparation of Metal foil laminates

Thermosetting resin compositions of examples 1 to 9 and comparative examples 1 to 6 were prepared in the proportions shown in tables 1 and 2, and the respective components were mixed at room temperature for 60 minutes using a stirrer, followed by addition of toluene (examples 1 to 9 and comparative examples 1 to 3 and 5 and 6) or MEK (comparative example 4). After the resulting mixture was stirred at room temperature for about 60 to 120 minutes, each of the thermosetting resin compositions was prepared.

Prepregs of examples 1 to 9 and comparative examples 1 to 6 were prepared using the prepared thermosetting resin compositions, respectively. First, the thermosetting resin compositions of examples 1 to 9 and comparative examples 2 to 6 were impregnated with a liquid crystal polymer nonwoven fabric or a glass fiber cloth, respectively, by a roll coater; alternatively, the thermosetting resin composition of comparative example 1 was applied to both the upper and lower surfaces of the liquid crystal polymer film by a coater to a thickness of 13 μm. Then, the impregnated or coated liquid crystal polymer nonwoven fabric, glass fiber cloth and liquid crystal polymer film were placed in a dryer at 160 ℃ to be heated and dried for 3 minutes, thereby producing a prepreg.

The prepared prepregs were used to prepare metal-foil laminates of examples 1 to 9 and comparative examples 1 to 6, respectively. The metal-foil laminates of examples 1 to 9 and comparative examples 1 to 6 were respectively prepared by laminating copper foils in contact with prepregs and then performing a hot-pressing operation. The hot pressing conditions are as follows: the temperature is raised to 200 ℃ to 220 ℃ at a temperature rise rate of 3.0 ℃/min, and hot pressing is carried out at the temperature for 180 minutes under a pressure of 15 kg/cm (initial pressure of 8 kg/cm). Table 1: compositions of prepregs of the examples

Table 2: composition of prepreg of comparative example

6.4. Property measurement of metal foil laminate

Properties of the metal foil laminates of examples 1 to 9 and comparative examples 1 to 6, including dielectric constant (Dk), dielectric dissipation factor (Df), flexibility, heat resistance after moisture absorption, and peel strength, were measured according to the measurement methods as described above, and the results are recorded in tables 3 and 4.

Table 3: properties of Metal foil laminate of examples

Table 4: properties of Metal foil laminate of comparative example

As shown in table 3, the metal-clad laminate prepared from the prepreg of the present invention has the advantages of good flexibility, low dielectric constant (Dk), low dielectric loss factor (Df), and high heat resistance, and also has high peel strength between the prepreg and the copper foil.

In contrast, as shown in table 4, the metal-clad laminate produced using the prepreg not according to the present invention could not achieve satisfactory levels in all physical and chemical properties and dielectric properties, and could not have good peel strength between the copper foil and the prepreg. Specifically, as shown in comparative example 1, when a liquid crystal polymer film was used for the metal foil laminate, the flexibility, peel strength and heat resistance were all inferior. As shown in comparative example 2, when NE-glass grade glass fiber cloth was used for the metal foil laminate, both flexibility and dielectric constant were not good. As shown in comparative example 3, when the thermosetting resin composition contains only the cyclic olefin copolymer, the heat resistance of the metal foil laminate is insufficient. As shown in comparative example 4, when compared with the thermosetting resin composition of the present invention, the electrical properties of the metal foil laminate could not be satisfied when other thermosetting resin compositions were used. As shown in comparative example 5, when the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (A) in the thermosetting resin composition is more than 7, the heat resistance of the metal foil laminate is insufficient. As shown in comparative example 6, when the weight ratio of the cyclic olefin copolymer (B) to the unsaturated monomer (a) in the thermosetting resin composition is less than 0.5, the metal foil laminate is poor in flexibility and peel strength.

The above embodiments are merely illustrative of the principles and effects of the present invention, and illustrate the technical features of the present invention, but do not limit the scope of the present invention. Any changes or arrangements which can be easily made by those skilled in the art without departing from the technical principle and spirit of the present invention shall fall within the scope of the present invention. Accordingly, the scope of the invention is as set forth in the following claims.