阅读说明：本技术 树脂组合物、半固化片、电路基板和印制电路板 (Resin composition, prepreg, circuit board and printed circuit board ) 是由 韩梦娜 卢悦群 任英杰 董辉 于 2020-03-27 设计创作，主要内容包括：本发明涉及一种树脂组合物,包括混合树脂、经过修饰的填料和固化剂,混合树脂包括第一树脂和第二树脂,第一树脂为乙烯基热固性树脂,第二树脂为能够与第一树脂反应的共聚物,经过修饰的填料为通过第三树脂对填料的表面进行修饰,第三树脂为能够与第一树脂反应的共聚物。本发明还涉及一种半固化片、电路基板和印制电路板。本发明通过对树脂组合物中混合树脂的选择和填料的改性、选择以及粒径的控制,使得到的电路基板能够同时兼顾介电常数、介电损耗、加工性能和PIM的影响。(The invention relates to a resin composition, which comprises mixed resin, a modified filler and a curing agent, wherein the mixed resin comprises first resin and second resin, the first resin is vinyl thermosetting resin, the second resin is a copolymer capable of reacting with the first resin, the modified filler is formed by modifying the surface of the filler through third resin, and the third resin is a copolymer capable of reacting with the first resin. The invention also relates to a prepreg, a circuit substrate and a printed circuit board. The invention can simultaneously take the influences of dielectric constant, dielectric loss, processability and PIM into consideration by selecting mixed resin in the resin composition, modifying and selecting fillers and controlling particle size.)

1. A resin composition comprising a mixed resin, a modified filler and a curing agent, wherein the mixed resin comprises a first resin and a second resin, the first resin is a vinyl thermosetting resin, the second resin is a copolymer capable of reacting with the first resin, the modified filler is a copolymer capable of modifying the surface of the filler with a third resin, and the third resin is a copolymer capable of reacting with the first resin.

2. The resin composition according to claim 1, wherein in the modified filler, the filler is encapsulated by the third resin.

3. The resin composition according to claim 1, wherein the vinyl thermosetting resin has a vinyl content of 60% or more and a molecular weight of 8000 or less.

4. The resin composition according to claim 3, wherein the vinyl thermosetting resin comprises at least one of a polydiene-based resin and a diene-styrene-based copolymer.

5. The resin composition according to claim 1, wherein the second resin and the third resin are each independently at least one selected from the group consisting of a linear block copolymer and a graft type block copolymer, and specifically at least one selected from the group consisting of a copolymer containing ethylene and propylene, a terpolymer, a styrene-butadiene-styrene triblock copolymer having an unsaturated bond, and a styrene-butadiene diblock copolymer.

6. The resin composition according to claim 1, wherein the modified filler has a particle size of 1 to 30 μm.

7. The resin composition according to claim 1, wherein the modified filler is used in an amount of 100 to 300 parts by weight and the curing agent is used in an amount of 1 to 10 parts by weight, based on100 parts by weight of the mixed resin.

8. The resin composition of claim 1, wherein the first resin is present in the mixed resin in an amount of 40 to 80% by weight.

9. A prepreg comprising a reinforcing material and the resin composition according to any one of claims 1 to 8 attached to the reinforcing material.

10. A circuit substrate comprising a dielectric layer and a metal foil provided on at least one surface of the dielectric layer, wherein the dielectric layer is cured from the prepreg according to claim 9.

11. The circuit substrate according to claim 10, wherein the number of the prepregs is plural, and the dielectric layer is obtained by stacking and curing the plural prepregs.

12. A printed circuit board comprising the circuit substrate according to any one of claims 10 to 11.

13. The printed circuit board of claim 12, wherein the printed circuit board has a hole thickness of 30 μm or less.

Technical Field

The invention relates to the technical field of electronic industry, in particular to a resin composition, a prepreg, a circuit substrate and a printed circuit board.

Background

In the field of high frequency circuit substrates, dielectric constant and dielectric loss are one of the key screening parameters that circuit substrates first consider. However, the processability of processing a circuit substrate into a Printed Circuit Board (PCB) has been less studied in the art. Specifically, when a circuit board is manufactured by selectively performing processing, etching, drilling and copper plating on the circuit board, the hole wall protrusion affects the hole diameter, which causes difficulty in inserting the circuit board, and the hole wall depression causes difficulty in depositing copper, even no copper is deposited, which causes no copper in the hole, so that the processing performance of the circuit board has a great influence on the quality of a finished product of the PCB.

Disclosure of Invention

In view of the above, it is necessary to provide a resin composition, a prepreg, a circuit board and a printed circuit board; the circuit substrate has good dielectric property and processing property, and can effectively reduce the interference of passive intermodulation products.

A resin composition comprising a mixed resin, a modified filler and a curing agent, wherein the mixed resin comprises a first resin and a second resin, the first resin is a vinyl thermosetting resin, the second resin is a copolymer capable of reacting with the first resin, the modified filler is a copolymer capable of reacting with the first resin, the surface of the filler is modified by a third resin, and the third resin is a copolymer capable of reacting with the first resin.

In one embodiment, the modified filler is encapsulated by the third resin.

In one embodiment, the vinyl thermosetting resin has a vinyl content of 60% or more and a molecular weight of 8000% or less.

In one embodiment, the vinyl thermosetting resin includes at least one of a polydiene-based resin, a diene-styrene-based copolymer.

In one embodiment, the second resin and the third resin are each independently at least one selected from the group consisting of a linear block copolymer and a graft-type block copolymer, and specifically include at least one of a copolymer containing ethylene and propylene, a terpolymer, a styrene-butadiene-styrene triblock copolymer having an unsaturated bond, and a styrene-butadiene diblock copolymer.

In one embodiment, the modified filler has a particle size of 1 μm to 30 μm.

In one embodiment, the modified filler is used in an amount of 100 to 300 parts by weight and the curing agent is used in an amount of 1 to 10 parts by weight, based on100 parts by weight of the mixed resin.

In one embodiment, the weight percentage of the first resin in the mixed resin is 40-80%.

The prepreg comprises a reinforcing material and the resin composition attached to the reinforcing material.

A circuit substrate comprises a dielectric layer and a metal foil arranged on at least one surface of the dielectric layer, wherein the dielectric layer is formed by solidifying the prepreg.

In one embodiment, the number of the prepregs is multiple, and the dielectric layer is obtained by stacking and curing the prepregs.

A printed circuit board comprises the circuit substrate.

In one embodiment, the hole thickness of the printed circuit board is less than or equal to 30 μm.

In the resin composition, the modified filler and the mixed resin have better compatibility, and in the curing and crosslinking process, the second resin in the mixed resin and the third resin modified on the surface of the filler react with the first resin to form chemical bonds to be polymerized together, so that the crosslinking density of the dielectric layer is improved, and the circuit substrate is endowed with good dielectric property, high temperature resistance and certain mechanical strength.

Meanwhile, the surface of the filler is modified with the third resin, so that the stress of the circuit board can be further released in the processing process of the PCB, the stress of the hole wall is more uniform during drilling, the PCB has better hole wall roughness, the hole thickness is less than or equal to 30 micrometers, and the interference of a Passive Intermodulation (PIM) product can be effectively reduced.

Drawings

Fig. 1 is a cut-away view of a circuit board with a thick hole during PCB processing according to embodiment 1 of the present invention;

fig. 2 is a cut-away view of a circuit board with a thick hole during PCB processing according to embodiment 2 of the present invention;

fig. 3 is a cut-away view of a circuit substrate with a thick hole during PCB processing according to embodiment 3 of the present invention;

fig. 4 is a rough cut-away view of a hole in a PCB processing process of a circuit substrate according to embodiment 4 of the present invention;

fig. 5 is a cut-away view of a circuit substrate of embodiment 5 of the present invention with a thick hole during PCB processing;

FIG. 6 is a cut-away view of a circuit substrate of comparative example 1 of the present invention with a coarse hole during PCB processing;

FIG. 7 is a cut-away view of a circuit substrate of comparative example 2 of the present invention with a coarse hole during PCB processing;

FIG. 8 is a cut-away view of a circuit substrate of comparative example 3 of the present invention with a coarse hole during PCB processing;

fig. 9 is a cut-away view of a circuit substrate of comparative example 4 of the present invention with a thick hole during PCB processing.

Detailed Description

The resin composition, prepreg, circuit board and printed circuit board provided by the present invention will be further described below.

The invention provides a resin composition, which comprises mixed resin, a modified filler and a curing agent, wherein the mixed resin comprises first resin and second resin, the first resin is vinyl thermosetting resin, the second resin is a copolymer capable of reacting with the first resin, the modified filler is formed by modifying the surface of the filler through third resin, and the third resin is a copolymer capable of reacting with the first resin.

After the surface of the filler is modified by the third resin, the filler and the mixed resin have better compatibility, and meanwhile, the hydroxyl on the surface of the filler is further reduced, and the polarity of the filler is reduced. In addition, in the curing and crosslinking process, the second resin in the mixed resin and the third resin modified on the surface of the filler react with the first resin to form chemical bonds and polymerize together, so that the crosslinking density of the resin composition can be improved, and the circuit substrate is endowed with good dielectric property, high temperature resistance and certain mechanical strength.

Meanwhile, the surface of the filler is modified with the third resin, so that the stress of the circuit board can be further released in the processing process of the PCB, the stress of the hole wall is more uniform during drilling, the PCB has better hole wall roughness, the hole thickness is less than or equal to 30 micrometers, and the interference of a Passive Intermodulation (PIM) product can be effectively reduced.

In order to better improve the dielectric property and the processing property of the circuit substrate, in the modified filler, the filler is preferably coated by the third resin, including partially coated or completely coated, and further preferably completely coated, so that the third resin and the filler exist in a core-shell structure.

The surface of the filler contains hydroxyl, the filler is pretreated by a silane coupling agent, the silane coupling agent can react with the hydroxyl on the surface of the filler to modify the surface of the filler, and then the third resin is grafted, so that the surface of the filler is modified by the third resin.

Specifically, the hydroxyl content of the surface of the filler can be increased, and then silane coupling agent pretreatment and third resin grafting are performed, so that more third resin is modified on the surface of the filler, and the filler can be wrapped by the third resin.

The method can be specifically carried out by the following steps:

step one, providing a first filler, performing surface pretreatment on the first filler by using a 0.2 mol/L-0.4 mol/L NaOH solution, stirring for 1-3 h at 80-90 ℃, then washing with pure water until the pH value is 6-8, performing suction filtration to remove water, and drying for 12-14 h at 100-105 ℃ to obtain a second filler;

preparing ethanol and water into a solution in a certain proportion, mixing the solution with a second filler and a silane coupling agent, stirring for 2-3 h at 80-90 ℃, washing and filtering with ethanol after the reaction is finished, putting into a drying oven at 100-105 ℃, and drying for 12-14 h to obtain a third filler;

and step three, placing the third filler into a xylene solution, adding third resin and an initiator, stirring and reacting for 12-14 h at 80-100 ℃, filtering, collecting, washing with xylene, and drying in vacuum at 40-50 ℃ to obtain the filler with the surface modified with the third resin.

Wherein the initiator comprises at least one of benzoyl peroxide, 2, 5-dimethyl-2, 5-di (benzyl peroxide) hexane and di-tert-butyl peroxide.

Specifically, the filler comprises at least one of titanium dioxide, barium titanate, strontium titanate, silicon dioxide, corundum, wollastonite, solid glass microspheres, hollow silicon dioxide microspheres, hollow titanium dioxide microspheres, synthetic glass, quartz, boron nitride, aluminum carbide, beryllium oxide, aluminum hydroxide, magnesium oxide, mica, talc and magnesium hydroxide, and the particle size of the modified filler is preferably 1 μm to 30 μm, and more preferably 5 μm to 20 μm.

Wherein, the silicon dioxide, the hollow glass microspheres and the hollow silicon dioxide microspheres are low-loss fillers, and the dielectric loss range of the fillers is 0.1 × 10^-3～4×10^-3. When the filler with the dielectric loss less than or equal to 0.004 is selected, the dielectric loss of the circuit substrate can be less than or equal to 0.004, and the dielectric performance of the circuit substrate is further improved.

Therefore, the circuit substrate has better dielectric property and processing performance through selection of the filler and control of the particle size range, has better pore thickness performance in the PCB processing process, and reduces the influence of PIM.

Specifically, the vinyl thermosetting resin has a vinyl content of 60% or more, preferably 70% or more, and a molecular weight of 8000 or less, preferably 6000 or less. The vinyl thermosetting resin comprises at least one of polydiene resin and diene-styrene copolymer, such as: polybutadiene, butadiene homopolymer, isoprene homopolymer, butadiene-styrene copolymer, isoprene-styrene copolymer, modified diene resin such as hydroxyl terminated, methacrylate terminated, and carboxylic acid terminated, or diene-styrene copolymer.

Illustratively, the vinyl thermosetting resin may be Ricon100, Ricon156, etc. from Sartomer corporation.

Specifically, the second resin and the third resin are each independently at least one selected from a linear block copolymer and a graft type block copolymer having an unsaturated group reactive with a vinyl group of the first resin, and specifically include at least one of a copolymer, a terpolymer, a styrene-butadiene-styrene triblock copolymer, and a styrene-butadiene diblock copolymer having an unsaturated bond, which contain ethylene and propylene.

Illustratively, the second resin and the third resin may be D1116, FG1924G, etc. of Kraton corporation.

Specifically, the curing agent decomposes to generate free radicals during curing, initiates a crosslinking reaction between unsaturated groups, and plays a role in accelerating curing, and comprises at least one of 2, 5-dimethyl-2, 5-di (benzyl peroxide) hexane, di-tert-butyl peroxide, 2, 5-dimethyl-2, 5-bis (tert-butylperoxy) hexane, 2, 5-dimethyl-2, 5-di-tert-butylperoxy-3-hexyne, and dicumyl peroxide.

Specifically, the modified filler is used in an amount of 100 to 300 parts by weight and the curing agent is used in an amount of 1 to 10 parts by weight, based on100 parts by weight of the mixed resin. Wherein, in the mixed resin, the weight percentage content of the first resin is 40-80%.

In order to mix the reinforcing material and the mixed resin uniformly, the resin composition can also comprise a coupling agent, preferably a silane coupling agent, and the use amount of the coupling agent is less than or equal to 5 parts by weight relative to 100 parts by weight of the mixed resin.

Therefore, the dielectric properties and processability of the circuit board can be further improved by selecting and adjusting the amount of the mixed resin system.

The invention also provides a prepreg, which comprises a reinforcing material and the resin composition attached to the reinforcing material.

Specifically, the reinforcing material is used for controlling the curing shrinkage of the circuit substrate in manufacturing and endowing the circuit substrate with certain mechanical strength, and the reinforcing material is preferably glass fiber cloth, including non-woven fabric or woven fabric, such as natural fiber, organic synthetic fiber and inorganic fiber, and is preferably electronic grade glass fiber cloth.

The reinforcing material is used in an amount of 100 to 200 parts by weight with respect to 100 parts by weight of the mixed resin.

Specifically, the mixed resin, the modified filler and the curing agent are mixed according to the weight ratio, the mixture is diluted to proper viscosity by a solvent, the filler is uniformly dispersed in the mixed resin to prepare a glue solution, the glue solution is impregnated by a reinforcing material, and then the solvent is removed to prepare the prepreg.

The invention also provides a circuit substrate which comprises a dielectric layer and a metal foil arranged on at least one surface of the dielectric layer, wherein the dielectric layer is formed by curing the prepreg.

Specifically, the number of the prepregs may be one or more, and when a plurality of prepregs are stacked, the prepregs are cured to obtain the dielectric layer.

Wherein the curing temperature is 150-280 ℃, and the curing pressure is 10kg/cm²～80kg/cm²During the curing process, the third resin in the mixed resin and the second resin modified on the surface of the filler react with the first resin to form chemical bonds and are polymerized together.

Specifically, the metal foil is preferably a copper foil, so that a high-frequency copper-clad plate can be obtained.

The invention also provides a printed circuit board which comprises the circuit substrate and is mainly manufactured by the circuit substrate through processes of drilling, hole trimming, micro etching, presoaking, activating, accelerating, chemical copper and copper thickening and the like.

The thickness of the hole of the printed circuit board is less than or equal to 30 microns, so that the good hole wall roughness is beneficial to signal conduction, and the influence of PIM can be effectively reduced.

Therefore, the present invention can simultaneously achieve the effects of dielectric constant, dielectric loss, processability and PIM by selecting a mixed resin in the resin composition, modifying and selecting a filler, and controlling particle size.

Hereinafter, the resin composition, prepreg, circuit substrate and printed circuit board will be further described by the following specific examples.

TABLE 1