阅读说明：本技术 一种电路材料和印刷电路板 (Circuit material and printed circuit board ) 是由 颜善银 介星迪 罗成 郭浩勇 许永静 于 2020-12-15 设计创作，主要内容包括：本发明涉及一种电路材料和印刷电路板,所述电路材料包括电介质基板层以及层叠设置在所述电介质基板层一侧或两侧的毛面粗糙度Rz≤3μm导电金属层；所述电介质基板层包括增强材料以及覆于所述增强材料上的树脂组合物,所述树脂组合物包括如下组分：数均分子量Mn≤5000g/mol的带有不饱和双键的热固性树脂；数均分子量Mn≥50000g/mol的带有不饱和双键的热固性树脂；粒径中值D50为2-5μm的球形二氧化硅填料；阻燃剂；复配自由基引发剂。本发明提供的电路材料可以满足高频电子电路基材对厚度均匀性、稳定的低介电常数、低介电损耗、全频段低PIM值、低的插损等综合性能的要求。(The invention relates to a circuit material and a printed circuit board, wherein the circuit material comprises a dielectric substrate layer and a conductive metal layer which is stacked on one side or two sides of the dielectric substrate layer and has rough surface roughness Rz less than or equal to 3 mu m; the dielectric substrate layer includes a reinforcement material and a resin composition overlying the reinforcement material, the resin composition including the following components: thermosetting resin with unsaturated double bonds and the number average molecular weight Mn of less than or equal to 5000 g/mol; thermosetting resin with unsaturated double bonds and with the number average molecular weight Mn of more than or equal to 50000 g/mol; spherical silica filler having a median particle diameter D50 of 2-5 μm; a flame retardant; compounding free radical initiator. The circuit material provided by the invention can meet the requirements of high-frequency electronic circuit base materials on the comprehensive performances of thickness uniformity, stable low dielectric constant, low dielectric loss, full-band low PIM value, low insertion loss and the like.)

1. A circuit material, comprising a dielectric substrate layer and a conductive metal layer laminated on one or both sides of the dielectric substrate layer;

the dielectric substrate layer includes a reinforcement material and a resin composition overlying the reinforcement material, the resin composition including the following components:

(A) the low molecular weight thermosetting resin with unsaturated double bonds has the number average molecular weight Mn less than or equal to 5000 g/mol;

(B) high molecular weight thermosetting resin with unsaturated double bond, the number average molecular weight Mn is not less than 50000 g/mol;

(C) spherical silica filler having a median particle diameter D50 of 2-5 μm;

(D) a flame retardant;

(E) compounding a free radical initiator;

the compound free radical initiator comprises the combination of at least one organic peroxide free radical initiator and at least one carbon-based free radical initiator, and the mass ratio of the organic peroxide free radical initiator to the carbon-based free radical initiator is 1:2-2: 1;

the initiation temperature of the organic peroxide free radical initiator is 110-150 ℃, and the half-life period at 110-150 ℃ is 1 hour;

the roughness Rz of the rough surface of the conductive metal layer is less than or equal to 3 mu m; the dielectric constant range of the dielectric substrate layer is less than or equal to 0.05 under the condition of 10GHz, and the dielectric loss is less than or equal to 0.0040;

the passive intermodulation value of the circuit material in the frequency band of 600MHz to 2600MHz is less than or equal to-158 dBc, and the insertion loss of the long and short lines under the condition of 2GHz is more than or equal to-0.25 dB/6 inch.

2. The circuit material according to claim 1, wherein the low molecular weight thermosetting resin having an unsaturated double bond comprises any one or a combination of at least two of a polyphenylene ether resin, a polybutadiene resin or a polybutadiene copolymer resin having an unsaturated double bond;

preferably, the polyphenylene ether resin with unsaturated double bonds comprises any one or at least two of polyphenylene ether resin with acryloyl groups at both terminal modifying groups, polyphenylene ether resin with styrene groups at both terminal modifying groups, or polyphenylene ether resin with vinyl groups at both terminal modifying groups;

preferably, the polybutadiene resin comprises any one or at least two of 1, 2-polybutadiene resin, maleic anhydride modified polybutadiene resin, acrylate modified polybutadiene resin, epoxy modified polybutadiene resin, amine modified polybutadiene resin, carboxyl-terminated modified polybutadiene resin or hydroxyl-terminated modified polybutadiene resin;

preferably, the polybutadiene copolymer resin includes any one of or a combination of at least two of a polybutadiene-styrene copolymer resin, a polybutadiene-styrene-divinylbenzene graft copolymer resin, a maleic anhydride-modified styrene-butadiene copolymer resin, or an acrylate-modified styrene-butadiene copolymer resin.

3. The circuit material of claim 1 or 2, wherein the high molecular weight thermosetting resin with unsaturated double bonds comprises any one or a combination of at least two of an elastomeric block copolymer, ethylene propylene rubber or polybutadiene rubber;

preferably, the elastomeric block copolymer comprises any one or a combination of at least two of a styrene-butadiene diblock copolymer, a styrene-butadiene-styrene triblock copolymer, a styrene- (ethylene-butylene) -styrene triblock copolymer, a styrene-isoprene diblock copolymer, a styrene-isoprene-styrene triblock copolymer, a styrene- (ethylene-propylene) -styrene triblock copolymer, or a styrene- (ethylene-butylene) diblock copolymer.

4. The circuit material of any of claims 1-3, wherein the surface of the spherical silica filler is treated with a coupling agent;

preferably, the coupling agent is a vinyl coupling agent;

preferably, the resin composition comprises the following components in parts by weight:

5. the circuit material of any of claims 1-4, wherein the flame retardant comprises a bromine-containing flame retardant and/or a phosphorus-containing flame retardant;

preferably, the bromine-containing flame retardant comprises any one or at least two of decabromodiphenyl ether, decabromodiphenyl ethane or ethylene bistetrabromophthalimide;

preferably, the phosphorus-containing flame retardant includes any one or at least two combinations of tris (2, 6-dimethylphenyl) phosphine, 10- (2, 5-dihydroxyphenyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2, 6-bis (2, 6-dimethylphenyl) phosphinobenzene, or 10-phenyl-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

6. The circuit material of any of claims 1-5 wherein the organic peroxide free radical initiator comprises any one or a combination of at least two of dicumyl peroxide, 1, 3-bis (t-butylperoxyisopropyl) benzene, 2, 5-di-t-butylperoxy-2, 5-dimethylhexane, 2, 5-di-t-butylperoxy-2, 5-dimethylhexyne-3, di-t-butyl peroxide, or t-butylcumyl peroxide;

preferably, the carbon-based radical initiator is any one selected from 2, 3-dimethyl-2, 3-diphenylbutane, 2, 3-dimethyl-2, 3-di (4-methylphenyl) butane, 2, 3-dimethyl-2, 3-di (4-isopropylphenyl) butane, 3, 4-dimethyl-3, 4-diphenylhexane, or a combination of at least two thereof.

7. The circuit material of any of claims 1-6, wherein the resin composition further comprises a hollow glass microsphere filler;

preferably, the addition amount of the hollow glass microsphere filler is 60-100 parts by weight;

preferably, the density of the hollow glass microsphere filler is 0.2-0.6g/cm³。

8. The circuit material of any of claims 1-7, wherein the resin composition further comprises an adjuvant;

preferably, the auxiliary agent comprises any one or a combination of at least two of an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a pigment, a colorant or a lubricant.

9. The circuit material of any of claims 1-8, wherein the reinforcing material is an electronic grade fiberglass cloth;

preferably, the conductive metal layer is a copper foil.

10. A printed circuit board comprising the circuit material of any one of claims 1-9;

preferably, the printed circuit board is a high frequency substrate.

Technical Field

The invention relates to the technical field of electronic materials, in particular to a circuit material and a printed circuit board.

Background

The 5G communication technology is a 5 th generation system of the mobile communication technology, faces the requirement of mobile communication after 2020, and meets the development requirement of mobile internet and all-thing internet services. Compared with the 4G communication technology, the 5G communication technology has the advantages of higher information transmission rate, higher spectrum utilization efficiency, lower time delay, more reliable information transmission, higher link density and the like. In order to meet the design requirements of wireless communication products in the 5 th generation communication era, the design of Multiple Input Multiple Output (MIMO) antennas, active antennas and multi-layer board antennas is a necessary trend in the 5G era. For the antenna application field in the 5G communication technology, the used base material is required to have stable dielectric constant, low dielectric loss, good multi-layer Printed Circuit Board (PCB) processability, good mechanical properties, low cost and the like, and new opportunities and challenges are brought to the Copper Clad Laminate (CCL).

Traditional Polytetrafluoroethylene (PTFE) substrates have low dielectric constants, low dielectric losses, and have been widely used in the rf microwave field. However, burrs exist in a drilling process of a base material in the PCB processing process, a glue removing process needs sodium naphthalene treatment, copper is not easy to be added to a hole wall in a copper precipitation process, green oil bubbles are prone to poor adhesion in a green oil process, board edge burrs exist in a board routing process, multi-layer boards are in contraposition offset and the like, and the traditional PTFE base material is low in modulus and large in thermal expansion coefficient, so that the phase fluctuation of the PCB is large, the PTFE material cannot meet the design requirements of most 5G-era antenna products, and the market trend is changing towards thermosetting materials.

In the design of the antenna, the stability and consistency of the dielectric constant and the thickness of the dielectric substrate material are important indexes influencing the gain and other performances of the antenna. Variations in the thickness of the dielectric substrate can cause the antenna to be less efficient. In the design of the antenna, the deviation of the dielectric layer thickness is a factor that has a greater influence on the antenna performance than the dielectric constant stability. Meanwhile, the deviation of the thickness also causes different resin contents, which also directly affects the stability of the dielectric constant.

In addition, the passive intermodulation value (PIM) and the insertion loss of the dielectric substrate material are also important indexes affecting the performance of the antenna. Especially, the PIM value is low, the terminal client requires that the full frequency band from low frequency (such as 600MHz) to high frequency (such as 2600MHz) has lower PIM value, and the frequency bands tested usually are 600MHz, 700MHz, 800MHz, 850MHz, 900MHz, 1400MHz, 1800MHz, 1900MHz, 2100MHz, 2600MHz and the like. The terminal feeds back some high-frequency substrates with PIM problems in low frequency bands, such as 800MHz, and with better PIM values in other frequency bands.

CN102304264A discloses a resin composition, which comprises high molecular weight polybutadiene resin, low molecular weight polybutadiene resin, modified polyphenyl ether thermosetting resin, inorganic powder, flame retardant, cross-linking agent, adhesion promoter and hardening initiator, and can improve the defects that pure polybutadiene is poor in too viscous processability and polyphenyl ether resin is poor in dissolution and a plasticizer is required to be added; in particular, the composite material is formed into a non-tacky prepreg, and the copper foil substrate can be formed using automated processing. However, the copper-clad plate prepared from the resin composition is difficult to realize a low PIM value in the full frequency band.

CN107197592A discloses a low PIM high performance microwave high frequency composite ceramic substrate, including microwave high frequency ceramic insulating medium material layer, microwave high frequency ceramic insulating medium material layer both sides are equipped with low PIM ceramic bonding sheet and inferior smooth copper foil layer in proper order. The surface roughness of the matte copper foil layer is less than 0.1 mu m, so that the resistance in the signal transmission process can be effectively reduced, and the generation amount of harmonic waves and combined frequency components can be reduced. However, the microwave high-frequency ceramic insulating dielectric material layer is formed by mixing polytetrafluoroethylene powder and low-temperature co-fired ceramic powder and then sintering the mixture at a high temperature, the thickness uniformity and the dielectric constant uniformity of the substrate are poor, and a low PIM value is difficult to realize in a full frequency band.

CN101157788A discloses a polybutadiene resin composition containing a low molecular weight 1, 2-polybutadiene which is a crosslinking component having a number average molecular weight of 1000-. However, this resin composition is difficult to achieve both thickness uniformity and dielectric constant uniformity, and cannot solve the problem of PIM in a low frequency band.

CN109504062A discloses a thermosetting resin composition, which comprises thermosetting polyphenylene oxide resin, thermosetting polybutadiene resin, thermoplastic resin, inorganic powder, flame retardant, cross-linking agent and composite cross-linking initiator, wherein multiple peroxides with different half-life temperatures are adopted to combine into the composite cross-linking initiator, so that the cross-linking density can be effectively improved in the thermal hardening process; and then compounded with cross-linking agent to form the composition, after hardening, the composition can reach the characteristics of low dielectric constant, low dielectric loss, high Tg, high rigidity, good cutting property of prepreg, and the like. Also, the resin composition is difficult to achieve both thickness uniformity and dielectric constant uniformity, and the problem of low-frequency PIM cannot be solved.

Therefore, it is necessary to develop a new circuit material, which has a requirement of higher thickness uniformity, stable dielectric constant, lower dielectric loss, lower passive intermodulation value and lower insertion loss in the full frequency band, so as to meet the performance requirement of the dielectric substrate for the antenna.

Disclosure of Invention

The invention aims to provide a circuit material, in particular to a copper-clad plate, and particularly provides a copper-clad plate for a high-frequency substrate, wherein the circuit material can meet the requirements of high-frequency electronic circuit substrates on the comprehensive performances of thickness uniformity, stable low dielectric constant, low dielectric loss, full-band low PIM value, low insertion loss and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a circuit material, which comprises a dielectric substrate layer and conductive metal layers stacked on one side or two sides of the dielectric substrate layer;

the dielectric substrate layer includes a reinforcement material and a resin composition overlying the reinforcement material, the resin composition including the following components:

(A) low molecular weight thermosetting resins with unsaturated double bonds, having a number average molecular weight Mn of 5000g/mol or less, for example 1000g/mol, 1200g/mol, 1400g/mol, 1600g/mol, 1800g/mol, 2000g/mol, 2200g/mol, 2400g/mol, 2600g/mol, 2800g/mol, 3000g/mol, 3200g/mol, 3400g/mol, 3600g/mol, 3800g/mol, 4000g/mol, 4200g/mol, 4400g/mol, 4600g/mol, 4800g/mol, etc.;

(B) high molecular weight thermosetting resins with unsaturated double bonds, with a number average molecular weight Mn of 50000g/mol, such as 60000g/mol, 70000g/mol, 80000g/mol, 90000g/mol, 100000g/mol, etc.;

(C) spherical silica fillers having a median particle diameter D50 of 2 to 5 μm, e.g., 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, and the like;

(D) a flame retardant;

(E) compounding a free radical initiator;

the compound free radical initiator comprises a combination of at least one organic peroxide free radical initiator and at least one carbon-based free radical initiator, wherein the mass ratio of the organic peroxide free radical initiator to the carbon-based free radical initiator is 1:2-2:1, such as 1.2:2, 1.4:2, 1.6:2, 1.8:2, 2:2, 2.2:2, 2.4:2, 2.6:2, 2.8:2, 3:2, 3.2:2, 3.4:2, 3.6:2, 3.8:2, and the like;

the initiation temperature of the organic peroxide radical initiator is 110-150 ℃ (such as 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃ and the like), and the half-life period at 110-150 ℃ is 1 hour;

the roughness Rz of the rough surface of the conductive metal layer is less than or equal to 3 μm, such as 1 μm, 2 μm and 3 μm; the dielectric constant range of the dielectric substrate layer is less than or equal to 0.05 under the condition of 10GHz, and the dielectric loss is less than or equal to 0.0040;

the passive intermodulation value of the circuit material in the frequency band of 600MHz to 2600MHz is less than or equal to-158 dBc, and the insertion loss of the long and short lines under the condition of 2GHz is more than or equal to-0.25 dB/6 inch.

The magnitude of the passive intermodulation value and the long and short line insertion loss, which are limited by the present invention, refer to the magnitude of the actual value, not the magnitude of the absolute value, and illustratively, the long and short line insertion loss is-0.15 dB/6inch > -0.25dB/6 inch. The case where the long and short line insertion loss is large (i.e., the case where the absolute value is low) is conventionally referred to as "low insertion loss" by those skilled in the art, and the present invention has the same meaning when referring to similar terms.

In the present invention, the inventors have surprisingly found that the PIM problem at certain low frequency bands, such as 800MHz, of high frequency substrates using angular silica fillers can be solved by using spherical silica fillers having a median particle size D50 in the range of 2 to 5 μm. The median D50 of the filler particle size is less than 2 μm, the glue viscosity is large, the production gluing process is not facilitated, the bonding sheet is easy to scratch in the gluing process, the glue cannot flow completely due to the large oil absorption value of the small-particle-size filler after heating and pressurizing, the scratch of the bonding sheet cannot be flattened, the thickness of the whole plate of the plate is unstable, the thickness consistency and the dielectric constant (Dk) consistency of the whole plate are poor, and the PIM value in a low frequency band is increased. The median D50 of the filler particle size is greater than 5 μm, and the glue flow is large when the plate is pressed, which easily forms ravines, and also easily causes uneven thickness of the plate, thereby affecting the consistency of the plate thickness and Dk, and increasing the PIM value in the low frequency band.

In addition, in order to ensure a high-frequency substrate having a good PIM value and a low insertion loss, the present invention requires the conductive metal layer to be used with a matte roughness Rz of 3 μm or less and also requires the dielectric loss (Df) of 0.0040(10GHz) or less for the dielectric substrate layer, so that a copper foil having a relatively low profile and a resin having a very low polarity are selected, which inevitably results in a low peel strength. The inventors have found through extensive studies that the use of an organic peroxide radical initiator having a relatively low reaction temperature results in a relatively large dielectric loss (Df) of the sheet material, and a relatively low curing reaction degree of the sheet material, and a low insertion loss value, and that the use of a carbon-based radical initiator having a relatively high reaction temperature results in a relatively low Df of the sheet material and a relatively high curing reaction degree of the sheet material, but the Peel Strength (PS) between the substrate and the low-profile copper foil is very low, and the Df, PS and curing reaction degree of the sheet material can be balanced by using a radical initiator compounded with the two.

In order to ensure that the high-frequency substrate has better thickness consistency and the consistency of the whole Dk, the inventor finds that the high-frequency substrate can have better thickness consistency and the consistency of the whole Dk by adding the thermosetting resin with unsaturated double bonds with high molecular weight and the thermosetting resin with unsaturated double bonds with low molecular weight into the formula and compounding the thermosetting resin with unsaturated double bonds with low molecular weight. Only the thermosetting resin with low molecular weight and unsaturated double bonds is added, glue flows after heating and pressurizing, gullies are easy to generate, the thickness of the plate edge is too thin, the thickness of the whole plate of the plate is unstable, and the Dk consistency of the whole plate is poor. If only high molecular weight thermosetting resin with unsaturated double bonds is added in the resin formula, the bonding sheet is easy to form stripes in the gluing process, the glue does not flow completely due to large molecular weight after being heated and pressurized, the stripes of the bonding sheet cannot be flattened, the thickness of the whole plate of the plate is unstable, and the Dk consistency of the whole plate is poor.

Preferably, the low molecular weight thermosetting resin (a) having an unsaturated double bond includes any one or a combination of at least two of a polyphenylene ether resin, a polybutadiene resin or a polybutadiene copolymer resin having an unsaturated double bond. The polybutadiene resin is homopolymeric polybutadiene, and does not include copolymerization.

Preferably, the polyphenylene ether resin having an unsaturated double bond includes any one of or a combination of at least two of a polyphenylene ether resin having acryl groups at both terminal modifying groups, a polyphenylene ether resin having styrene groups at both terminal modifying groups, or a polyphenylene ether resin having vinyl groups at both terminal modifying groups.

Preferably, the polybutadiene resin includes any one or a combination of at least two of 1, 2-polybutadiene resin, maleic anhydride modified polybutadiene resin, acrylate modified polybutadiene resin, epoxy modified polybutadiene resin, amine modified polybutadiene resin, carboxyl-terminated modified polybutadiene resin, or hydroxyl-terminated modified polybutadiene resin.

Preferably, the polybutadiene copolymer resin includes any one of or a combination of at least two of a polybutadiene-styrene copolymer resin, a polybutadiene-styrene-divinylbenzene graft copolymer resin, a maleic anhydride-modified styrene-butadiene copolymer resin, or an acrylate-modified styrene-butadiene copolymer resin.

Preferably, the high molecular weight thermosetting resin (B) having an unsaturated double bond includes any one or a combination of at least two of an elastomeric block copolymer, ethylene propylene rubber, or polybutadiene rubber. The polybutadiene rubber is a homopolymeric polybutadiene rubber, and copolymerization is not included.

Preferably, the elastomeric block copolymer comprises any one or a combination of at least two of a styrene-butadiene diblock copolymer, a styrene-butadiene-styrene triblock copolymer, a styrene- (ethylene-butylene) -styrene triblock copolymer, a styrene-isoprene diblock copolymer, a styrene-isoprene-styrene triblock copolymer, a styrene- (ethylene-propylene) -styrene triblock copolymer, or a styrene- (ethylene-butylene) diblock copolymer.

Preferably, the spherical silica filler is surface treated with a coupling agent. The filler subjected to the surface treatment by the coupling agent has better dispersibility.

Preferably, the coupling agent is a vinyl coupling agent.

Preferably, the flame retardant (D) comprises a bromine-containing flame retardant and/or a phosphorus-containing flame retardant.

Preferably, the bromine-containing flame retardant comprises any one or at least two of decabromodiphenyl ether, decabromodiphenyl ethane or ethylene bistetrabromophthalimide;

preferably, the phosphorus-containing flame retardant includes any one or at least two combinations of tris (2, 6-dimethylphenyl) phosphine, 10- (2, 5-dihydroxyphenyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2, 6-bis (2, 6-dimethylphenyl) phosphinobenzene, or 10-phenyl-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

Preferably, the organic peroxide free radical initiator comprises any one or a combination of at least two of dicumyl peroxide, 1, 3-bis (t-butylperoxyisopropyl) benzene, 2, 5-di-t-butylperoxy-2, 5-dimethylhexane, 2, 5-di-t-butylperoxy-2, 5-dimethylhexyne-3, di-t-butyl peroxide or t-butylcumyl peroxide.

Preferably, the carbon-based radical initiator is selected from any one of 2, 3-dimethyl-2, 3-diphenylbutane, 2, 3-dimethyl-2, 3-di (4-methylphenyl) butane, 2, 3-dimethyl-2, 3-di (4-isopropylphenyl) butane, 3, 4-dimethyl-3, 4-diphenylhexane or a combination of at least two thereof;

preferably, the resin composition further comprises a hollow glass microsphere filler (F).

Preferably, the amount of the hollow glass microsphere filler added is 60 to 100 parts by weight, such as 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, and the like.

Preferably, the density of the hollow glass microsphere filler is 0.2-0.6g/cm³E.g. 0.3g/cm³、0.4g/cm³、0.5g/cm³And the like.

Preferably, the resin composition further comprises an auxiliary agent.

Preferably, the auxiliary agent comprises any one or a combination of at least two of an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a pigment, a colorant or a lubricant.

The term "comprising" as used herein means that it may include, in addition to the components, other components which impart different characteristics to the resin composition. In addition, the term "comprising" as used herein may be replaced by "being" or "consisting of … …" as closed.

The resin composition of the present invention can also be used in combination with various high polymers as long as it does not impair the inherent properties of the resin composition. Specifically, for example, a liquid crystal polymer, a thermoplastic resin, various flame retardant compounds or additives, and the like; they may be used alone or in combination of plural kinds as required.

Preferably, the resin composition comprises the following components in parts by weight:

in the above formulation, the amount of the low molecular weight thermosetting resin having an unsaturated double bond added is 70 to 200 parts by weight, for example, 80 parts by weight, 90 parts by weight, 100 parts by weight, 120 parts by weight, 140 parts by weight, 150 parts by weight, 190 parts by weight, or the like; the amount of the high molecular weight unsaturated double bond-bearing thermosetting resin added is 50 to 60 parts by weight, for example, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, or the like; the spherical silica filler having a median particle diameter D50 of 2 to 5 μm is added in an amount of 560-700 parts by weight, for example, 570 parts by weight, 580 parts by weight, 590 parts by weight, 600 parts by weight, 620 parts by weight, 640 parts by weight, 660 parts by weight, 680 parts by weight, etc.; the amount of the flame retardant to be added is 90 to 100 parts by weight, for example, 91 parts by weight, 92 parts by weight, 93 parts by weight, 94 parts by weight, 95 parts by weight, 96 parts by weight, 97 parts by weight, 98 parts by weight, 99 parts by weight, etc.; the addition amount of the compound free radical initiator is 8-16 parts by weight, such as 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight and the like; the amount of the hollow glass microsphere filler added is 60 to 100 parts by weight, for example, 70 parts by weight, 80 parts by weight, 90 parts by weight, and the like.

Preferably, the reinforcing material is electronic grade glass fiber cloth.

Preferably, the circuit material is a copper-clad plate.

Preferably, the conductive metal layer is a copper foil.

Preferably, the copper foil has a thickness of 9-150 μm, such as 12 μm, 20 μm, 30 μm, 40 μm, 50 μm, 70 μm, 90 μm, 110 μm, 120 μm, 130 μm, 140 μm, and the like.

The method for producing the resin composition of the present invention can be carried out by a known method: stirring, mixing, and the like. The filler particle size testing method adopts a Malvern 2000 laser particle size analyzer for testing; the test method of the number average molecular weight Mn in the invention is GB/T21863-2008, and is determined by gel permeation chromatography based on polystyrene calibration; the method for testing the rough surface roughness Rz of the conductive metal layer is a non-contact laser method.

In the present invention, the method for preparing the circuit material is not particularly limited, and illustratively, the method for preparing the circuit material is as follows:

(1) dissolving or dispersing the resin composition in a solvent to prepare a glue solution, soaking glass fiber cloth, drying, and removing the solvent to prepare a prepreg;

2) and (3) stacking at least one prepreg together, placing the prepreg between two copper foils, and then placing the copper foils into a laminating machine to obtain the circuit material through hot-pressing and curing.

In the above-mentioned production method, an organic solvent may be used as needed, and the organic solvent is not particularly limited as long as it is compatible with each component of the resin composition, and specific examples thereof include: alcohols such as methanol, ethanol and butanol, ethers such as ethyl cellosolve, butyl cellosolve, ethylene glycol methyl ether, diethylene glycol ethyl ether and diethylene glycol butyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene, xylene and mesitylene, esters such as ethoxyethyl acetate and ethyl acetate, and nitrogen-containing solvents such as N, N-dimethylformamide, N-dimethylacetamide and N-methyl-2-pyrrolidone. The above solvents may be used singly or in combination of two or more.

It is a second object of the present invention to provide a printed circuit board comprising the circuit material according to the first object.

Preferably, the printed circuit board is a high frequency substrate. The high-frequency substrate refers to a special circuit board with higher electromagnetic frequency, and is defined as a substrate with frequency above 1GHz in the invention.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, the spherical silica filler with D50 of 2-5 μm is added into the resin composition, so that the PIM problem of the angular silica filler used for the high-frequency substrate at certain low frequency bands such as 800MHz can be solved, the effect of low PIM is realized at all frequency bands, and the thickness consistency and Dk consistency of the circuit material are improved.

(2) According to the invention, the compound free radical initiator of the organic peroxide free radical initiator and the carbon-based free radical initiator in a specific ratio is adopted, so that even if a conductive metal layer with the rough surface roughness Rz of less than or equal to 3 mu m is adopted, higher peel strength can be obtained, and low insertion loss, low Df and higher curing reaction degree are ensured.

(3) According to the invention, the thermosetting resin with unsaturated double bonds and the low-molecular-weight thermosetting resin with unsaturated double bonds are compounded for use, so that the high-frequency substrate has better thickness consistency and the consistency of the whole Dk.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

The following examples and comparative examples relate to materials and brand information as shown in table 1:

TABLE 1

Examples 1 to 10

Resin compositions (raw material amount units are parts by weight) were prepared according to the components shown in table 2, and copper-clad laminate samples were prepared according to the following preparation methods:

(1) dissolving and mixing the components according to the formula amount, adding the mixture into a reaction kettle, diluting the mixture to a proper viscosity by using methylbenzene, and stirring and mixing the mixture uniformly to obtain a resin glue solution.

(2) Infiltrating glass fiber cloth with resin glue solution (the unit of the reinforcing material is the number of the sheets in table 2), drying to remove solvent, baking to be in a semi-cured state, then superposing a plurality of sheets, respectively laminating a copper foil (the unit of the conductive metal layer is the number of the sheets in table 2) on the upper and lower sides, putting the copper foil into a press for curing to obtain the copper-clad laminate, wherein the curing temperature is 240 ℃, and the curing pressure is 50kg/cm²。

Comparative examples 1 to 10

Resin compositions (raw material amount units are parts by weight) were prepared according to the components shown in table 3, and copper clad laminate samples were prepared according to the same preparation method as in examples.

In table 3, the unit of the reinforcing material and the conductive metal layer is the number of sheets.

TABLE 2

TABLE 3

And (3) performance testing:

the copper-clad plates provided in examples 1 to 10 and comparative examples 1 to 10 were subjected to a performance test by the following method:

(1) dielectric constant (Dk) and dielectric loss (Df): testing the dielectric constant Dk and the dielectric loss Df of the board by adopting an SPDR method under the frequency of 10 GHz;

(2) peel Strength (PS): according to the experimental condition of 'after thermal stress' in the IPC-TM-6502.4.8 method, testing the peel strength of the plate, wherein the unit of the peel strength is N/mm;

(3) thickness uniformity: taking five samples at four corners of the plate and the middle position of the plate to test the thickness of the plate, wherein if the thickness of the plate meets the three-level tolerance of the copper-clad plate, the thickness consistency is good, and if the thickness of the plate cannot meet the three-level tolerance of the copper-clad plate, the thickness consistency is poor;

(4) dk identity: five samples are taken at four corners of the plate and the middle position of the plate to test the dielectric constant Dk of the plate, if the Dk range of the plate is less than or equal to 0.05, the Dk consistency is good, and if the Dk range of the plate is more than 0.05, the Dk consistency is poor;

(5) passive intermodulation value (PIM): testing is carried out by using a Summitek Instruments PIM analyzer, and the unit of PIM is dBc;

(6) and (3) inserting and damaging the long and short wires: the measurement was carried out according to the method defined by 2.5.5.12A in IPC-TM-650, the test frequency was 2GHz and the insertion loss was in dB/6 inch.

The results of the tests on the laminates provided in examples 1-10 and comparative examples 1-10 are shown in tables 4 and 5, respectively.

TABLE 4

Performance testing	Example 1	Example 2	Example 3	Example 4	Example 5
						Dk(10GHz)	3.58	3.62	3.59	3.55	3.18
Df(10GHz)	0.0030	0.0036	0.0031	0.0029	0.0035
						PS	0.90	1.20	0.92	0.98	1.10
Uniformity of thickness	Good taste	Good taste	Good taste	Good taste	Good taste
						Dk consistency	Good taste	Good taste	Good taste	Good taste	Good taste
PIM(600MHz)	-163.9	-164.8	-164.5	-166.0	-164.9
						PIM(700MHz)	-165.2	-168.0	-164.4	-164.5	-163.0
PIM(800MHz)	-170.1	-172.4	-168.7	-169.8	-171.3
						PIM(850MHz)	-163.5	-161.9	-164.5	-161.0	-162.1
PIM(900MHz)	-168.6	-168.0	-168.8	-165.7	-161.0
						PIM(1400MHz)	-169.7	-169.0	-170.8	-165.9	-166.3
PIM(1800MHz)	-161.0	-161.0	-160.9	-166.5	-171.8
						PIM(1900MHz)	-162.1	-162.7	-162.0	-162.0	-162.2
PIM(2100MHz)	-162.9	-162.6	-162.8	-164.1	-163.7
						PIM(2600MHz)	-167.2	-161.1	-170.8	-168.5	-173.5
Loss (2GHz)	-0.18	-0.22	-0.19	-0.18	-0.21
						Performance testing	Example 6	Example 7	Example 8	Example 9	Example 10
Dk(10GHz)	3.16	2.80	3.35	3.34	3.36
						Df(10GHz)	0.0031	0.0036	0.0031	0.0030	0.0035
PS	1.30	1.05	1.12	0.95	1.18
						Uniformity of thickness	Good taste	Good taste	Good taste	Good taste	Good taste
Dk consistency	Good taste	Good taste	Good taste	Good taste	Good taste
						PIM(600MHz)	-159.5	-163.8	-161.0	-162.1	-160.3
PIM(700MHz)	-163.9	-164.5	-164.2	-163.4	-161.7
						PIM(800MHz)	-170.1	-167.5	-167.2	-168.4	-165.6
PIM(850MHz)	-161.4	-162.5	-159.7	-161.6	-158.9
						PIM(900MHz)	-160.0	-158.7	-160.4	-162.7	-161.8
PIM(1400MHz)	-160.1	-169.6	-178.1	-177.2	-175.7
						PIM(1800MHz)	-168.1	-171.2	-170.1	-172.3	-168.2
PIM(1900MHz)	-163.0	-161.6	-161.3	-162.7	-160.6
						PIM(2100MHz)	-163.4	-165.1	-163.4	-162.8	-162.6
PIM(2600MHz)	-170.5	-170.7	-172.1	-171.4	-170.5
						Loss (2GHz)	-0.18	-0.23	-0.20	-0.18	-0.22

TABLE 5

Performance testing	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5
						Dk(10GHz)	3.57	3.60	3.68	3.53	3.15
Df(10GHz)	0.0029	0.0032	0.0035	0.0030	0.0034
						PS(N/mm)	0.90	0.85	0.75	0.96	1.15
Uniformity of thickness	Difference (D)	Difference (D)	Difference (D)	Difference (D)	Good taste
						Dk consistency	Difference (D)	Difference (D)	Difference (D)	Difference (D)	Good taste
PIM(600MHz)	-163.0	-164.9	-163.5	-158.7	-158.6
						PIM(700MHz)	-163.9	-163.0	-161.0	-158.4	-159.0
PIM(800MHz)	-164.2	-165.1	-163.1	-161.4	-152.1
						PIM(850MHz)	-161.2	-161.7	-158.4	-158.9	-159.6
PIM(900MHz)	-160.1	-162.5	-161.1	-160.1	-162.4
						PIM(1400MHz)	-168.2	-168.7	-171.1	-165.2	-163.2
PIM(1800MHz)	-162.1	-161.1	-161.1	-160.7	-158.9
						PIM(1900MHz)	-161.8	-161.8	-161.9	-158.9	-158.5
PIM(2100MHz)	-165.3	-161.7	-162.0	-160.2	-159.8
						PIM(2600MHz)	-164.8	-165.1	-161.8	-162.1	-162.7
Loss (2GHz)	-0.18	-0.20	-0.22	-0.19	-0.21
						Performance testing	Comparative example 6	Comparative example 7	Comparative example 8	Comparative example 9	Comparative example 10
Dk(10GHz)	3.12	2.80	3.38	3.36	3.39
						Df(10GHz)	0.0029	0.0034	0.0038	0.0035	0.0037
PS	1.32	0.55	0.92	0.57	0.94
						Uniformity of thickness	Good taste	Good taste	Good taste	Good taste	Good taste
Dk consistency	Good taste	Good taste	Good taste	Good taste	Good taste
						PIM(600MHz)	-159.1	-157.4	-160.2	-159.3	-158.8
PIM(700MHz)	-158.6	-153.7	-158.5	-157.8	-157.9
						PIM(800MHz)	-154.1	-158.7	-162.8	-161.5	-161.7
PIM(850MHz)	-160.0	-156.8	-161.5	-160.6	-160.2
						PIM(900MHz)	-162.3	-156.5	-158.2	-159.4	-158.9
PIM(1400MHz)	-159.2	-158.5	-167.7	-165.2	-164.3
						PIM(1800MHz)	-162.4	-154.4	-161.9	-160.8	-160.2
PIM(1900MHz)	-159.8	-153.6	-160.5	-161.4	-159.2
						PIM(2100MHz)	-159.3	-159.4	-164.8	-163.7	-162.6
PIM(2600MHz)	-160.7	-157.6	-167.0	-166.4	-165.3
						Loss (2GHz)	-0.18	-0.26	-0.28	-0.26	-0.27

As can be seen from the examples and performance tests, the dielectric substrate layer of the invention has stable dielectric constant, the dielectric constant (Dk) of the dielectric substrate layer is extremely poor less than or equal to 0.05(10GHz), and simultaneously has lower dielectric loss, the dielectric loss (Df) of the dielectric substrate layer is less than or equal to 0.0040(10GHz), and the Peel Strength (PS) of the substrate and the copper foil is more than 0.70N/mm. The circuit material composed of the conductive metal layer and the dielectric substrate layer has a low passive intermodulation value (PIM) less than or equal to-158 dBc (600MHz to 2600MHz) and low insertion loss (2GHz) greater than or equal to-0.25 dB/6 inch. Can meet the performance requirements of the dielectric substrate for the antenna.

As is clear from the comparison between examples 1-2 and comparative examples 1-2, in the resin composition provided in the present invention, a thermosetting resin having a low molecular weight and an unsaturated double bond and a thermosetting resin having a high molecular weight and an unsaturated double bond are added at the same time, and if only a thermosetting resin having a low molecular weight and an unsaturated double bond is added (comparative example 1), flow occurs after heat and pressure are applied, thereby generating a gap, and the thickness of the edge position of the panel is too thin, the thickness of the entire panel is unstable, and the Dk uniformity of the entire panel is poor. If only high molecular weight thermosetting resin with unsaturated double bonds is added (comparative example 2), the bonding sheet is easy to form stripes in the gluing process, the glue does not flow completely due to the large molecular weight after being heated and pressed, the stripes of the bonding sheet cannot be flattened, and thus the thickness of the whole plate of the plate is unstable, and the Dk consistency of the whole plate is poor.

As is clear from the comparison between examples 3 to 4 and comparative examples 3 to 4, the median diameter D50 of the spherical silica filler in the resin composition provided in the present invention must be in the range of 2 to 5 μm, and if the median diameter D50 of the spherical silica filler is less than 2 μm (comparative example 3), the viscosity of the glue is too high to facilitate the sizing process, the adhesive sheet is liable to form scratches during the sizing process, and the small-diameter filler does not flow at all due to its high oil absorption value after heat and pressure application, and the scratches of the adhesive sheet cannot be flattened, so that the thickness of the whole sheet is unstable, resulting in poor Dk uniformity of the whole sheet and an increase in PIM value at low frequency. If the median filler particle diameter D50 of the spherical silica filler is greater than 5 μm (comparative example 4), the flow of glue is large when the board is pressed, which tends to form ravines, and also tends to cause non-uniform thickness of the board, thereby affecting the uniformity of the thickness of the board and the uniformity of the dielectric constant (Dk), and increasing the PIM value at low frequency.

As is apparent from the comparison between examples 5 to 6 and comparative examples 5 to 6, if the spherical silica filler in the resin composition of the present invention is replaced with the angular silica filler (comparative examples 5 to 6), in the case where the oil absorption value of the formulated filler is secured to be equivalent, and the thickness uniformity and the dielectric constant (Dk) uniformity of the sheet are also equivalent, it is found that the PIM at 800MHz has a value of > -158dBc and the PIM at other frequency bands has no problem when the angular silica filler is used, thereby proving that the present invention can solve the PIM problem at some low frequency bands such as 800MHz by using the spherical silica filler.

As is clear from the comparison between example 7 and comparative example 7, if the built-up radical initiator in the resin composition of the present invention is replaced with a single carbon-based radical initiator having a higher reaction temperature (comparative example 7), i.e., a copper foil having a higher matte roughness is used, the Peel Strength (PS) between the substrate and the copper foil is also lower, and although the dielectric loss (Df) of the dielectric substrate layer is lower, the passive intermodulation value (PIM) of comparative example 7 is > -158dBc, while the long and short line insertion loss is < -0.25dB/6inch (2GHz), because the matte roughness of the copper foil used is higher than 3 μm.

As can be seen from the comparison between example 8 and comparative example 8, if the formulated radical initiator in the resin composition of the present invention is replaced by a single organic peroxide radical initiator with a lower reaction temperature, the Df of the sheet material will be larger and the curing reaction degree of the sheet material will be lower, although the Peel Strength (PS) and passive intermodulation value (PIM) of the substrate and copper foil can satisfy the requirement, but the long and short line insertion loss is < -0.25dB/6inch (2 GHz). In addition, the curing reaction degree of the board is low, and the problems of warping, dust drilling and dirt discharge difficulty and the like can occur in the PCB processing process.

As can be seen from the comparison between examples 9-10 and comparative examples 9-10, the invention can improve the comprehensive performance of the plate by selecting the organic peroxide radical initiator and the carbon-based radical initiator in the ratio of 1:2-2:1, and the comprehensive performance of low Df, high PS, high curing reaction degree and low insertion loss cannot be met by adding too much of either of the initiators.

Therefore, the circuit material for a high-frequency substrate of the present invention, which comprises the conductive metal layer and the dielectric substrate layer, particularly the resin composition constituting the dielectric substrate layer, is a comprehensive solution, and can satisfy the requirements of the high-frequency electronic circuit substrate for stable comprehensive properties such as low dielectric constant, low dielectric loss, low PIM value in full frequency band, low insertion loss, etc.

The present invention is illustrated in detail by the examples described above, but the present invention is not limited to the details described above, i.e., it is not intended that the present invention be implemented by relying on the details described above. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.