A surface treatment agent for reinforced materials and its application

Abstract

The present invention provides a reinforcing material surface treatment agent and its application. The reinforcing material surface treatment agent includes a silane coupling agent shown in formula A, a pH acidic regulator, a dispersant, a surfactant, and pure water. The surface treatment agent of the present invention plays a bridging role at the interface between the resin and the reinforcing material, especially the interface between the resin containing unsaturated bonds and the reinforcing material, can achieve low dielectric loss, low water absorption, and can still maintain low dielectric properties after water absorption. In addition, after laser drilling, there is no obvious "whisker-like" glass fiber residue on the side wall of the hole. The hole forming quality is highly reliable and can be applied to high-frequency and high-speed printed circuit boards, especially high-frequency and high-speed printed circuit boards for making fine circuits and micropores.

Description

Technical Field

[0001] The invention belongs to the technical field of reinforcing materials and relates to a surface treatment agent for reinforcing materials and application thereof. Background Art

[0002] Electronic fiberglass cloth is used as an insulation reinforcement material for printed circuit boards. It must be combined with resin to form a prepreg, which is then pressed with copper foil to create a metal-clad laminate, which is then used to print circuit boards. It should be noted that fiberglass cloth alone cannot bond with resin and typically requires surface treatment with a silane coupling agent. Silane coupling agent molecules contain inorganic and organic functional groups. The inorganic functional groups bond to the fiberglass cloth, while the organic functional groups bond to the resin. The coupling agent's bridging effect allows the fiberglass cloth and resin to form a single, integrated structure.

[0003] CN103911861A discloses a surface treatment agent formula for electronic-grade glass fiber cloth and a preparation method for a silane coupling agent. The formula is as follows: silane coupling agent A, with the general formula Y(CH2), n SiX3, content 0.1%-0.50%; silane coupling agent B, general formula (X3Si)Y(CH2) n (SiX3), content 0.05%-0.3%; acetic acid 0.1%-2%; deionized water as the balance. This invention can improve the heat resistance and ion migration resistance of glass fiber cloth, but the surface treatment agent is an amino-based surface treatment agent. Amino groups are polar groups and easily absorb water, making the glass fiber cloth produced with this method difficult to use in high-frequency, high-speed circuit substrates.

[0004] In recent years, miniaturization of electronic devices has driven the need for finer and higher-density wiring on printed circuit boards (PCBs). PCB build-up typically involves alternating insulating and conductive layers. While PCBs built with prepreg or resin sheets containing reinforcement materials offer excellent mechanical strength, the presence of glass fiber cloth can leave noticeable "whiskers" of glass fiber on the sidewalls of laser-drilled holes. These fibers can reduce the fluidity of the plating solution during the subsequent electroplating process, resulting in uneven plating within the channel holes and impacting the reliability of the resulting hole quality.

[0005] Therefore, in this field, it is desired to develop a surface treatment agent for reinforcing materials, in which the circuit substrate using the reinforcing material has low dielectric loss, low water absorption, can maintain low dielectric properties after absorbing water, and has no obvious "whisker-like" glass fiber residue on the side wall of the hole after laser drilling, and the hole quality is highly reliable. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a surface treatment agent for reinforcing materials and applications thereof, in particular to provide a surface treatment agent for glass fiber cloth and applications thereof.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In one aspect, the present invention provides a surface treatment agent for a reinforcing material, comprising a silane coupling agent represented by formula A, a pH acidic regulator, a surfactant, and pure water;

[0009]

[0010] Where R 1 each independently represents an alkyl group having 1 to 10 carbon atoms (e.g., 1, 2, 4, 6, 8, or 10) or an aryl group having 6 to 10 carbon atoms (e.g., 6, 7, 8, 9, or 10), and R 2 Each of the groups independently represents an alkyl group having 1 to 10 carbon atoms (e.g., 1, 2, 4, 6, 8, or 10) or an aryl group having 6 to 10 carbon atoms (e.g., 6, 7, 8, 9, or 10), e, f, g, and h independently represent an integer from 1 to 40 (e.g., 1, 3, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, or 40), and m represents an integer from 1 to 3 (e.g., 1, 2, or 3), wherein the order of the repeating units is arbitrary.

[0011] The styrene-butadiene polymer silane coupling agent represented by formula A of the present invention has a side chain containing multiple unsaturated bonds, which can increase the crosslinking density between the reinforcing material and the resin with unsaturated bonds at the interface between the reinforcing material and the resin. At the same time, compared with other small-molecule silane coupling agents, the silane coupling agent with a macromolecular structure is less volatile during the process of drying the surface treatment of the reinforcing material, and the crosslinking density can be increased using a low content of the silane coupling agent.

[0012] Considering the handling properties of the silane coupling agent represented by Formula A of the present invention, the number average molecular weight of the silane coupling agent represented by Formula A is preferably 500 to 100,000, more preferably 1,000 to 20,000. The number average molecular weight is a polystyrene-equivalent value obtained by gel permeation chromatography.

[0013] Preferably, in Formula A, f / (e+f+g+h) is 0.22 or greater, more preferably 0.22 or greater, further preferably 0.25 or greater, and particularly preferably 0.30 or greater. The upper limit is not particularly limited, but is preferably 1 or less, and more preferably 0.8 or less.

[0014] In the present invention, the silane coupling agent shown in the formula A is used as a reinforcing material surface treatment agent, because the main chain of the structure is composed of two elements of carbon and hydrogen, without polar groups, it has the performance of low dielectric constant and low dielectric loss, and because the side chain contains multiple unsaturated bonds, the cross-linking density of the system can be increased. The silane coupling agent plays a bridging effect on the interface of resin and reinforcing material (such as glass fiber cloth), particularly at the interface of the resin containing unsaturated bonds and reinforcing material, the interface consistency after cross-linking and curing is good, the processability of laser on glass fiber 1 and prepreg insulating layer 2 two materials can be made to converge, fracture is uniform during laser undercutting, and after laser drilling, the hole sidewall does not have obvious " whisker-like" glass fiber residue, and the hole forming quality is highly reliable; low dielectric loss, low water absorption, water absorption can be achieved simultaneously and low dielectric performance can still be maintained, so that the prepreg or the resin sheet prepared by the reinforcing material prepared by the surface treatment agent prepared by the silane coupling agent can be applied to high-frequency and high-speed printed circuit boards, particularly the high-frequency and high-speed printed circuit boards of fine circuits and micropores.

[0015] Preferably, based on the total weight of the reinforcing material surface treatment agent as 100%, the content of the silane coupling agent represented by formula A is 0.2%-3%, preferably 0.8-1.5%, for example 0.2%, 0.5%, 0.8%, 1%, 1.5%, 1.8%, 2%, 2.5%, 2.8% or 3%. If the content of the silane coupling agent represented by formula A is too low, the surface treatment of the glass fiber cloth is insufficient and the coating is not good, resulting in relatively easy moisture absorption. If the content of the silane coupling agent represented by formula A is too high, excess silane coupling agent of this structure will remain, and when it comes into contact with water, it will form silanols, which will also increase the possibility of moisture absorption of the system.

[0016] Preferably, the pH adjuster adjusts the pH of the surface treatment agent to 4-6, for example, 4, 4.5, 4.8, 5, 5.3, 5.5, 5.8, or 6, to improve the water solubility of the silane coupling agent. The pH adjuster can be any type as long as it can adjust the pH of the system to 4-6. Preferably, the pH adjuster is selected from any one or a combination of at least two of acetic acid, formic acid, phosphoric acid, or trifluoroacetic acid, with acetic acid being more preferred.

[0017] Preferably, based on the total weight of the reinforcing material surface treatment agent as 100%, the content of the pH acidic regulator is 0.2-0.45%, for example, 0.2%, 0.25%, 0.3%, 0.35%, 0.38%, 0.4%, 0.42% or 0.45%, preferably 0.3%.

[0018] Preferably, based on the total weight of the reinforcing material surface treatment agent as 100%, the content of the dispersant is 0.25-5%, for example, 0.25%, 0.3%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%.

[0019] Preferably, the dispersant comprises any one or a combination of at least two of an alcohol solvent, an ether solvent, an aromatic hydrocarbon solvent, an ester solvent, or a nitrogen-containing solvent. The silane coupling agent represented by formula A used in the present invention is oily, and diluting and dispersing it with a dispersant can improve the hydrolysis efficiency.

[0020] Preferably, the content of the surfactant is 0.01% to 0.15%, such as 0.01%, 0.05%, 0.08%, 0.1%, 0.13%, or 0.15%, preferably 0.01% to 0.05%, based on the total weight of the reinforcement material surface treatment agent as 100%. The surfactant has good water solubility and wetting properties, which can greatly reduce the surface tension of the surface treatment agent, facilitate rapid penetration of the surface treatment agent into the interior of the reinforcement, and improve the efficiency and effectiveness of the surface treatment.

[0021] Preferably, the surfactant is any one of a fluorocarbon surfactant or a silanol surfactant, or a combination of the two.

[0022] Preferably, the reinforcing material is glass fiber cloth.

[0023] In another aspect, the present invention provides a reinforcing material, wherein the reinforcing material is a reinforcing material treated with the reinforcing material surface treatment agent as described above.

[0024] In another aspect, the present invention provides a prepreg comprising the reinforcing material as described above and a resin composition attached to the reinforcing material after impregnation and drying.

[0025] Preferably, the resin composition includes a resin containing an unsaturated bond.

[0026] Preferably, the resin containing an unsaturated bond includes any one or a combination of at least two of an unsaturated bond-containing polyphenylene ether, a multifunctional vinyl aromatic copolymer, a styrene-butadiene-styrene polymer, a styrene-butadiene polymer, a styrene-isoprene polymer, polybutadiene, polyisoprene, a cyanate resin, an unsaturated cycloolefin copolymer, an allyl-modified benzoxazine, triallyl isocyanurate, triallyl cyanurate or maleimide.

[0027] In another aspect, the present invention provides a resin sheet comprising one or at least two laminated prepregs as described above, and a base film located on one side or both sides of the laminated prepregs.

[0028] Preferably, the base film is selected from any one of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, cyclic polyolefin, triacetyl cellulose, polyether sulfide, polyether ketone, polyimide, polytetrafluoroethylene, polybenzimidazole, polyetheretherketone or polyphenylene sulfide.

[0029] Preferably, a resin composition layer is further provided between the base film and the prepreg.

[0030] In another aspect, the present invention provides a laminate comprising at least one prepreg as described above.

[0031] In another aspect, the present invention provides a metal foil-clad laminate comprising one or at least two laminated prepregs as described above, and metal foil located on one side or both sides of the laminated prepregs.

[0032] Preferably, the metal foil is copper foil.

[0033] In another aspect, the present invention provides a high-frequency and high-speed circuit substrate, comprising one or at least two stacked prepregs as described above.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The surface treatment agent of the present invention plays a bridging role on the interface between the resin and the reinforcing material (especially the glass fiber cloth). In particular, at the interface between the resin containing unsaturated bonds and the reinforcing material, the interface consistency after cross-linking and curing is good, no obvious "whisker-like" glass fiber remains on the side wall of the hole after laser drilling, and the hole formation quality is highly reliable. At the same time, low dielectric loss and low water absorption can be achieved, and low dielectric properties can still be maintained after water absorption. Therefore, prepregs or resin sheets prepared from reinforcing materials treated with the surface treatment agent prepared by the silane coupling agent can be used in high-frequency and high-speed printed circuit boards, especially in the production of high-frequency and high-speed printed circuit boards with fine circuits and micropores. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic cross-sectional view of a blind hole in the prepreg insulation layer formed on the printed circuit board obtained in Example 1;

[0037] Among them, 1 is glass fiber cloth and 2 is prepreg insulation layer. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0039] In the following examples and comparative examples, the sources of the raw materials used are as follows:

[0040] Polyphenylene ether resin containing unsaturated bonds: SA9000, SABIC;

[0041] Styrene-butadiene resin: Ricon 100, Sartomer Company, USA;

[0042] Inorganic filler: spherical silica, NSQ002, Jiangsu Lianrui;

[0043] Initiator: dicumyl peroxide DCP, Shanghai Fangruida Chemical;

[0044] Flame retardant: decabromodiphenyl ethane, SAYTEX80 10, Albemarle Corporation, USA;

[0045] Silane coupling agent represented by formula A: styrene-butadiene polymer silane coupling agent, X-12-1281C, Shin-Etsu Chemical of Japan.

[0046] Example 1

[0047] In this embodiment, based on the total weight of the reinforcing material surface treatment agent as 100%, the reinforcing material surface treatment agent includes 1% of a silane coupling agent represented by Formula A, 0.3% of acetic acid (CAS No. 64-19-7), 3% of anhydrous ethanol, 0.013% of a surfactant (OFX-5211, Dow Corning), and the balance is pure water.

[0048] After desizing, the 1035NE glass fiber cloth is impregnated with the pre-dissolved and dispersed surface treatment agent, dried, washed with water, and dried again for standby use.

[0049] 30 parts by weight of unsaturated polyphenylene ether resin, 22 parts of styrene-butadiene resin, 30 parts of inorganic filler, 3 parts of initiator, and 15 parts of flame retardant were dissolved in toluene and mixed at room temperature to produce a 60% solids adhesive. 1035NE glass fiber cloth treated with a surface treatment agent was impregnated with the pre-dissolved adhesive and dried in a forced-air oven at 130°C for 4 minutes to produce a prepreg with an average thickness of 50 μm.

[0050] Four sheets of the above-obtained prepreg were stacked, and electrolytic copper foil with a thickness of 18 μm was pressed on the upper and lower sides of the prepreg. 2After curing for 2 hours, a metal foil-clad laminate with a core thickness of 0.20 mm was obtained.

[0051] The metal foil laminate was printed into a circuit substrate, and the prepreg and release polyethylene terephthalate (PET) base film were laminated on the surface of the circuit substrate in sequence. 2 The laminate was laminated and then thermally cured at 180°C for 30 minutes to form an insulating layer on the circuit substrate. After peeling off the release PET base film, the insulating layer was drilled using a Mitsubishi Electric ML605GTWII-P laser driller (using a 2mJ energy, 4μs pulse width, and 3 irradiations) to create blind vias with a top diameter of 70μm and a bottom diameter of 60μm.

[0052] Example 2

[0053] The only difference between this embodiment and embodiment 1 is that the reinforcing material surface treatment agent includes 0.2% of the silane coupling agent shown in formula A, 0.2% of acetic acid, 0.2% of anhydrous ethanol, 0.01% of a surfactant, and the balance is pure water.

[0054] Example 3

[0055] The only difference between this embodiment and embodiment 1 is that the reinforcing material surface treatment agent includes 3% of the silane coupling agent shown in formula A, 0.25% of acetic acid, 3.3% of anhydrous ethanol, 0.15% of a surfactant, and the balance is pure water.

[0056] Example 4

[0057] The only difference between this embodiment and embodiment 1 is that the amount of the silane coupling agent represented by formula A in embodiment 1 is adjusted to 4.5%, and the amount of anhydrous ethanol is adjusted to 5%.

[0058] Example 5

[0059] The only difference between this embodiment and embodiment 1 is that the amount of the silane coupling agent represented by formula A in embodiment 1 is adjusted to 0.05%.

[0060] Comparative Example 1

[0061] The only difference between this comparative example and Example 1 is that the silane coupling agent represented by formula A in Example 1 is replaced by an equal mass of KBM-1003 (vinyltrimethoxysilane, Shin-Etsu Chemical, Japan, with the structural formula: ).

[0062] Comparative Example 2

[0063] The only difference between this comparative example and Example 1 is that the silane coupling agent represented by formula A in Example 1 is replaced by an equal mass of X-12-1281B-ES (styrene-butadiene polymer silane coupling agent, Shin-Etsu Chemical, Japan, with the structural formula: ).

[0064] Comparative Example 3

[0065] The only difference between this comparative example and Example 1 is that the 1035NE glass fiber cloth is not treated with a surface treatment agent after desizing, and 3 parts of a silane coupling agent represented by formula A are added to the resin glue.

[0066] The metal foil-clad laminates and circuit substrates of the examples and comparative examples were subjected to performance tests using the following methods:

[0067] (1) Water absorption: Determined according to IPC-TM-650 2.6.2.1;

[0068] (2) Dielectric constant D k , dielectric loss D f :Referring to IPC-TM-650 2.5.5.15, the dielectric constant D of the laminate at 10GHz was measured using the Split Post Dielectric Resonator (SPDR) method. k and dielectric loss D f ;

[0069] (3) Dielectric loss after water absorption (D f ): Take the above-mentioned tested dielectric loss (D f ) samples were placed in an environment with a temperature of 25°C and a humidity of 55% for one week, and the dielectric loss (D f );

[0070] △D f : Dielectric loss after water absorption (D f )-dielectric loss before water absorption (D f );

[0071] (4) Length of “whisker-like” glass fibers: After the blind holes of the insulating layer stacked on the circuit substrate are decontaminated, the cross-section of the blind holes of the insulating layer is observed using a scanning electron microscope (SEM) to measure the maximum residual length of the glass fibers along the horizontal direction on the side walls of the blind holes.

[0072] The performance test comparison of the above embodiment and comparative example is shown in Table 1 below:

[0073] Table 1

[0074]

[0075]

[0076] As can be seen from Examples 1 to 3, the present invention can bridge the interface between the resin and the reinforcing material (such as glass fiber cloth) by adding an appropriate amount of the silane coupling agent represented by Formula A to treat the reinforcing material, especially the interface between the resin containing unsaturated bonds and the reinforcing material, and can achieve low dielectric loss and low water absorption. The low dielectric properties can still be maintained after water absorption, and there is no obvious "whisker-like" glass fiber residue on the side wall of the hole after laser drilling, and the hole quality is highly reliable.

[0077] Compared with Example 1, if the content of the silane coupling agent shown in Formula A is too high or too low in Example 4 and Example 5, it will, to a certain extent, lead to increased water absorption of the metal foil-clad laminate and deterioration of the dielectric properties after water absorption, and the "whisker-like" glass fibers on the sidewalls of the holes will become longer after laser drilling.

[0078] Compared to Example 1, Comparative Example 1 replaced the silane coupling agent represented by Formula A used in Example 1 with a silane coupling agent containing only one unsaturated bond (vinyltrimethoxysilane). Comparative Example 2 replaced the silane coupling agent represented by Formula A used in Example 1 with another styrene-butadiene polymer silane coupling agent whose side chains do not contain multiple unsaturated bonds. Comparative Example 3 was not treated with a surface treatment agent, resulting in essentially no crosslinking between the interface between the reinforcing material and the resin containing unsaturated bonds. Consequently, the dielectric properties of Comparative Examples 1-3 deteriorated after water absorption, and the "whisker-like" glass fibers on the sidewalls of the laser-drilled holes were very long, seriously affecting the quality and reliability of the hole formation.

[0079] The applicant states that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A prepreg, characterized in that The prepreg comprises a reinforcing material and a resin composition attached to the reinforcing material after impregnation and drying; The reinforcing material is a reinforcing material obtained by treating with a reinforcing material surface treatment agent; The reinforcing material is glass fiber cloth; The reinforcing material surface treatment agent includes a silane coupling agent shown in formula A, a pH acidic regulator, a dispersant, a surfactant and pure water; Where R 1 each independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, and R 2 Each of the repeating units independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; e, f, g and h independently represent an integer of 1 to 40; and m represents an integer of 1 to 3. The order of the repeating units is arbitrary.

2. The prepreg according to claim 1, characterized in that Based on the total weight of the reinforcing material surface treatment agent being 100%, the content of the silane coupling agent represented by formula A is 0.2%-3%.

3. The prepreg according to claim 2, characterized in that Based on the total weight of the reinforcing material surface treatment agent being 100%, the content of the silane coupling agent represented by formula A is 0.8-1.5%.

4. The prepreg according to claim 1, characterized in that The pH acidic regulator adjusts the pH of the surface treatment agent to 4-6.

5. The prepreg according to claim 1, characterized in that The pH acidic regulator is selected from any one of acetic acid, formic acid, phosphoric acid or trifluoroacetic acid, or a combination of at least two thereof.

6. The prepreg according to claim 5, characterized in that The pH acidic regulator is selected from acetic acid.

7. The prepreg according to claim 1, characterized in that Based on the total weight of the reinforcing material surface treatment agent being 100%, the content of the pH acidic regulator is 0.2-0.45%.

8. The prepreg according to claim 1, characterized in that Based on the total weight of the reinforcing material surface treatment agent being 100%, the content of the dispersant is 0.25-5%.

9. The prepreg according to claim 1, characterized in that The dispersant includes any one of alcohol solvents, ether solvents, aromatic hydrocarbon solvents, ester solvents, or nitrogen-containing solvents, or a combination of at least two thereof.

10. The prepreg according to claim 1, characterized in that Based on the total weight of the reinforcing material surface treatment agent being 100%, the content of the surfactant is 0.01%-0.15%.

11. The prepreg according to claim 10, characterized in that Based on the total weight of the reinforcing material surface treatment agent being 100%, the content of the surfactant is 0.01%-0.05%.

12. The prepreg according to claim 1, characterized in that The surfactant is any one of a fluorocarbon surfactant and a silanol surfactant, or a combination of the two.

13. The prepreg according to claim 1, characterized in that The resin composition includes a resin containing an unsaturated bond.

14. The prepreg according to claim 13, characterized in that The resin containing an unsaturated bond includes any one or a combination of at least two of an unsaturated bond-containing polyphenylene ether, a multifunctional vinyl aromatic copolymer, a styrene-butadiene-styrene polymer, a styrene-butadiene polymer, a styrene-isoprene polymer, polybutadiene, polyisoprene, a cyanate resin, an unsaturated cycloolefin copolymer, an allyl-modified benzoxazine, triallyl isocyanurate, triallyl cyanurate or maleimide.

15. A resin sheet, characterized in that: The resin sheet comprises one or at least two stacked prepregs according to any one of claims 1 to 14, and a base film located on one side or both sides of the stacked prepregs.

16. The resin sheet according to claim 15, wherein The base film is selected from any one of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, cyclic polyolefin, triacetyl cellulose, polyether sulfide, polyether ketone, polyimide, polytetrafluoroethylene, polybenzimidazole, polyetheretherketone or polyphenylene sulfide.

17. The resin sheet according to claim 15, wherein A resin composition layer is further provided between the base film and the prepreg.

18. A laminated board, characterized in that: The laminate comprises at least one prepreg according to any one of claims 1 to 14.

19. A metal foil-clad laminate, characterized in that: The metal foil-clad laminate comprises one or at least two stacked prepregs according to any one of claims 1 to 14, and metal foil located on one side or both sides of the stacked prepregs.

20. A high-frequency and high-speed circuit substrate, characterized in that: The high-frequency and high-speed circuit substrate comprises one or at least two stacked prepregs according to any one of claims 1 to 14.

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