Low-dielectric resin glue solution for high-frequency and high-speed copper-clad plate as well as preparation method and application of low-dielectric resin glue solution

Abstract

The invention belongs to the technical field of electronic materials, and relates to a low-dielectric resin glue solution for a high-frequency high-speed copper-clad plate as well as a preparation method and application thereof, and the low-dielectric resin glue solution for the high-frequency high-speed copper-clad plate comprises the following components in parts by weight: 100 parts of a resin component, 2-4 parts of a compatibilizer, 2.5-4.5 parts of a curing system, 0.6-1.3 parts of an initiator, 55-80 parts of a filler and 1.1-2.3 parts of an auxiliary agent. By introducing a ternary interpenetrating network of the polybutylbenzene resin, the polyimide and the allyl-terminated modified polyphenyl ether, a resin compounding system is optimized; the copper-clad plate with the comprehensive performance of ultralow dielectric constant, ultralow dielectric loss, high peel strength and low Z-axis thermal expansion coefficient is realized by adopting double-initiator gradient curing, filler compounding dispersion and low-dielectric glass fabric-HVLP copper foil synergistic interface treatment; the method is suitable for high-frequency scenes such as 5G communication base stations and millimeter wave radars.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic materials and relates to a low-dielectric resin adhesive for high-frequency and high-speed copper-clad laminates, and a preparation method and application thereof. Background Art

[0002] Existing high-speed resin systems for copper clad laminates, such as modified polyphenylene ether, have low Dk and Df, but have the following problems: 1. Poor interface bonding: Traditional resins have weak bonding strength with copper foil (peel strength < 0.5N / mm), which can easily lead to signal transmission loss; 2. Insufficient heat resistance: high risk of delamination at high temperatures (heat resistance time < 500 seconds); 3. Uneven dispersion of fillers: Flame retardants and silica tend to agglomerate when mixed, resulting in CTE fluctuations (Z-CTE>2.0%). Summary of the Invention

[0003] In view of the shortcomings of the above-mentioned prior art, the present invention provides a low-dielectric resin adhesive for high-frequency and high-speed copper-clad laminates, and a preparation method and application thereof. The specific technical solutions are as follows: The first object of the present invention is to provide a low dielectric resin adhesive for high-frequency and high-speed copper-clad laminates, comprising the following components in parts by weight: Resin component 100 parts, compatibilizer 2-4 parts, curing system 2.5-4.5 parts, initiator 0.6-1.3 parts, filler 55-80 parts, additive 1.1-2.3 parts; The resin component includes 25-35 parts of styrene-butadiene-styrene block copolymer (SBS), 20-30 parts of ethylene-norbornene copolymer, 30-40 parts of polyimide (PI) and 25-35 parts of terminal allyl-modified polyphenylene ether (PPO-Allyl); the allyl substitution degree of the terminal allyl-modified polyphenylene ether is ≥90%; the compatibilizer is maleic anhydride (MAH); the curing system includes 1.5-2.5 parts of triallyl isocyanurate (TAIC) and 1-2 parts of triallyl cyanurate (TAC); and the auxiliary agent includes 1-2 parts of a coupling agent and 0.1-0.3 parts of a leveling agent. This invention incorporates a ternary interpenetrating network of poly(butadiene styrene) resin, polyimide, and terminal allyl-modified poly(phenylene ether). The flexible chain segments of the poly(butadiene styrene) resin (SBS) reduce internal stress; the ethylene-norbornene copolymer has a heat-resistant backbone, inhibiting high-temperature degradation; the polyimide provides a low-dielectric core, and the crosslinked network of the terminal allyl-modified poly(phenylene ether) (PPO-Allyl) reduces polarity. Maleic anhydride, a compatibilizer, is first graft-copolymerized with the poly(butadiene styrene) resin and ethylene-norbornene copolymer before being cured with the polyimide and terminal allyl-modified poly(phenylene ether), reducing phase separation and improving resin compatibility. The curing system retards and inhibits the polymerization of hydrocarbon resins, facilitating the control of a partially cured state at the B-stage. The triazine ring, with three allyl groups, acts as a compatibilizer for terminally allyl-modified polyphenylene ether (TPE), effectively reducing the particle size of the TPE dispersed phase within the epoxy resin continuous phase. The cured product exhibits heat resistance, withstanding temperatures up to 300°C without change. Its structure is highly symmetrical, and its dielectric constant exhibits minimal frequency-dependent variations. It readily forms graft copolymers with TPE because the methyl groups on the TPE backbone are attacked by free radicals from triallyl isocyanurate (TAIC). Therefore, a certain degree of prepolymerization is recommended to improve impregnation, adhesion, and heat resistance. Triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC) each offer advantages at different pressing temperature gradients.

[0004] Furthermore, the initiator includes 0.1-0.3 parts of dicumyl peroxide (DCP) and 0.5-1.0 parts of diallyl phthalate (DAP).

[0005] The present invention adopts dual initiators of diisopropylbenzene oxide (DCP) and diallyl phthalate (DAP) to perform gradient synergistic initiation, with DCP initiating at low temperature and DAP activating at high temperature, triggering the crosslinking of TAIC and TAC in stages, thus avoiding stress concentration caused by premature gelation.

[0006] Furthermore, the filler includes 10-15 parts of DOPO flame retardant, 30-40 parts of spherical silica, and 15-25 parts of angular silica.

[0007] The present invention adopts a filler compounding strategy. The angular silica enhances the interfacial bonding between the resin and the glass fiber cloth through a mechanical anchoring effect. That is, the surface of the angular silica is rough, which facilitates mechanical interlocking with the glass fiber cloth and improves the bonding strength. The spherical filler reduces the CTE. The DOPO flame retardant can provide flame retardant properties.

[0008] Furthermore, the polystyrene-butadiene resin has a styrene content of 45%-55%, the ethylene-norbornene copolymer has a 5-ethylidene norbornene (ENB) content of 10%-15%, and the polyimide has an intrinsic viscosity of 0.5-0.7 dL / g.

[0009] Furthermore, the terminal allyl-modified polyphenylene ether is a difunctional acrylic acid-terminated 2,6-dimethyl polyphenylene ether, such as SA9000 from Sabic.

[0010] Furthermore, the particle size of the DOPO flame retardant is 2-4 μm, and the phosphorus content is ≥9%; the average particle size of the spherical silica is 0.5 μm, Dk<3.8, and the average particle size of the angular silica is 1.5 μm, and the aspect ratio is 4:1.

[0011] Furthermore, the coupling agent is a silane coupling agent, such as KH-560, and the leveling agent is BYK-333.

[0012] A second object of the present invention is to provide a method for preparing the above-mentioned low-dielectric resin adhesive for high-frequency and high-speed copper-clad laminates, comprising the following steps: Step 1, resin premixing and compatibilization: melt-mixing polybutadiene styrene resin and ethylene-norbornene copolymer at 80-100° C. for 30-60 minutes, then adding polyimide and terminal allyl-modified polyphenylene ether; stirring at 500-1000 rpm for 2-3 hours under nitrogen protection; heating to 100-120° C., adding a compatibilizer, and extruding through a twin-screw extruder to generate a graft copolymer matrix; Step 2, filler pretreatment: dry-mix the filler and the coupling agent in a mixer at a rotation speed of 1000-2000 rpm for 15-30 minutes, and then treat in an oven at 120-150°C for 1-3 hours to form a siloxane coating layer to obtain a pretreated filler; Step 3, gradient mixing and initiator dispersion: The graft copolymer matrix produced in step 1 is cooled to 70-80°C, and the curing system, initiator, and leveling agent are added in sequence. After stirring for 15-45 minutes, the pretreated filler obtained in step 2 is added in four batches, with an interval of 5-15 minutes between each batch, to finally obtain a mixed solution with a viscosity controlled at 2500-3500 cps; Step 4: Vacuum degassing: ultrasonically degas the mixture under vacuum for 30-60 minutes to obtain a low dielectric resin adhesive for high-frequency and high-speed copper clad laminates.

[0013] Furthermore, the temperature of the twin-screw extruder is 120-140° C., and the screw speed is 200-300 rpm.

[0014] The third object of the present invention is to provide a high-frequency and high-speed copper-clad laminate, which is prepared using the low-dielectric resin glue for high-frequency and high-speed copper-clad laminate according to any one of claims 1 to 5.

[0015] Furthermore, the method for preparing the high-frequency and high-speed copper-clad laminate comprises the following steps: Apply the resin glue liquid on the electric glass fiber cloth, controlling the glue content to 60-80%; then cover it with copper foil and cure it in a hot press: the temperature of the first stage is 90-110℃, the time is 10-80min; the temperature of the second stage is 120-180℃, the time is 10-80min; the temperature of the third stage is 180-210℃, the time is 20-40min.

[0016] In the curing process for preparing the high-frequency and high-speed copper-clad laminate of the present invention, in the first stage, DCP triggers TAIC pre-crosslinking with a crosslinking degree of 20%-30%; in the second stage, DAP activates and deeply crosslinks TAC with a crosslinking degree greater than 85%; and in the third stage, complete curing is carried out with a crosslinking degree of ≥95%.

[0017] Furthermore, the copper foil is HVLP copper foil with a roughness Rz≤1.5 μm.

[0018] The present invention adopts HVLP copper foil, whose low roughness forms a chemical-physical dual bond with the low-polarity surface of the resin glue, and the peel strength is improved by more than 30%.

[0019] Furthermore, the dielectric glass fiber cloth is low dielectric glass fiber cloth, such as low dielectric glass fiber cloth D1078.

[0020] The beneficial effects of the present invention are: The present invention optimizes the resin compounding system by introducing a ternary interpenetrating network of polybutadiene styrene resin, polyimide, and terminal allyl modified polyphenylene ether; adopts dual initiator gradient curing, filler compounding and dispersion, and low dielectric glass fiber cloth-HVLP copper foil collaborative interface treatment to achieve a copper clad laminate with comprehensive performance of ultra-low dielectric constant (Dk < 3.5), ultra-low dielectric loss (Df < 0.002), high peel strength (≥ 0.6N / mm) and low Z-axis thermal expansion coefficient (Z-CTE ≤ 1.8%); it is suitable for high-frequency scenarios such as 5G communication base stations and millimeter-wave radars. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a graph of the Z-CTE test data (50-260°C) of the present invention. DETAILED DESCRIPTION

[0022] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0023] Example 1: A high-frequency and high-speed copper-clad laminate, the preparation method of which comprises the following steps: Step 1: Resin premixing and compatibilization The polystyrene-butadiene resin and ethylene-norbornene copolymer were melt-mixed at 90°C for 40 minutes, and polyimide powder and terminal allyl-modified polyphenylene ether were added; the mixture was stirred at 600 rpm for 1.5 hours under nitrogen protection; the temperature was raised to 115°C, and the compatibilizer maleic anhydride MAH was added. The mixture was extruded through a twin-screw extruder at a temperature of 130°C and a screw speed of 250 rpm to produce a graft copolymer matrix; The invention comprises, by weight, 30 parts of polybutadiene-styrene resin, 25 parts of ethylene-norbornene copolymer, 35 parts of polyimide, and 30 parts of terminal allyl-modified polyphenylene ether; the terminal allyl-modified polyphenylene ether is a difunctional acrylic acid-terminated 2,6-dimethyl polyphenylene ether produced by Sabic (China) Co., Ltd.; 3 parts of maleic anhydride as a compatibilizer; the polybutadiene-styrene resin has a styrene content of 45%-55%, the ethylene-norbornene copolymer has a 5-ethylidene norbornene (ENB) content of 10%-15%; and the polyimide has an intrinsic viscosity of 0.5-0.7 dL / g. Step 2: Filler pretreatment DOPO flame retardant, spherical silica, angular silica and silane coupling agent KH-560 were dry-mixed in a high-speed mixer at 1500 rpm for 20 minutes, and then treated in an oven at 130°C for 2 hours to form a siloxane coating layer to obtain a pretreated filler; Among them, by weight, the DOPO flame retardant is 12 parts, with a particle size of 2-4 μm and a phosphorus content of ≥9%; spherical silica is 35 parts, with an average particle size of 0.5 μm and Dk < 3.8; angular silica is 20 parts, with an average particle size of 1.5 μm and an aspect ratio of 4:1; and silane coupling agent KH-560 is 1.5 parts; Step 3: Gradient mixing and initiator dispersion The product of step 1 was cooled to 75° C., and methyl triallyl isocyanurate TAIC, triallyl cyanurate TAC, dicumyl oxide DAP, diallyl phthalate DCP, and leveling agent BYK-333 were added in sequence. After stirring for 30 minutes, the pretreated filler was added in four batches with an interval of 10 minutes between each batch. The final viscosity was controlled at 2500-3500 cps to obtain a mixed solution. Wherein, by weight, the said triallyl isocyanurate is 2 parts, triallyl cyanurate is 1.5 parts, dicumyl oxide is 0.8 parts, diallyl phthalate is 0.2 parts and leveling agent BYK-333 is 0.2 parts; Step 4: Vacuum degassing and coating The mixed solution was ultrasonically degassed (50kHz) for 40 minutes under a vacuum of -0.098 MPa to obtain a resin adhesive. The resin adhesive was then coated on a low-dielectric glass fiber cloth D1078, with the adhesive content controlled to 70%. Step 5: Copper coating and step curing Covered with ultra-low profile HVLP copper foil (roughness Rz ≤ 1.5μm), cured by hot press step: The first stage: 100℃ / 1h (DCP initiates TAIC pre-crosslinking, crosslinking degree 20%-30%); The second stage: 150℃ / 1h (DAP activation, TAC deep cross-linking, cross-linking degree>85%); The third stage: 200℃ / 0.5h (complete curing, cross-linking degree ≥95%).

[0024] Comparative Example 1: In this comparative example, no terminal allyl-modified polyphenylene ether is contained, and other components and preparation methods are the same as those in Example 1, which will not be described again here.

[0025] Comparative Example 2: In this comparative example, angular silica is not contained, and other components and preparation methods are the same as those in Example 1, which will not be described again here.

[0026] The performance of the copper clad laminates prepared in the examples and comparative examples was tested, and the test results are shown in Table 1. The Z-CTE test data (50-260°C) are shown in Table 1. Figure 1 shown.

[0027] Peel strength: IPC-TM-650; Heat resistance (288℃, s): plug welding method, JIS C6481; Z-CTE: TMA method, IPC-TM-650.

[0028] Table 1 Performance test results of copper clad laminates prepared in Examples and Comparative Examples

[0029] The high-frequency, high-speed copper-clad laminate (CCL) of this invention optimizes the resin compound system by incorporating a ternary interpenetrating network of polybutadiene-styrene resin, polyimide, and terminal allyl-modified polyphenylene ether. Combined with dual-initiator gradient curing, filler compounding and dispersion, and a synergistic interface treatment between low-dielectric glass fiber cloth and HVLP copper foil, this overcomes technical bottlenecks and achieves a comprehensive performance CCL with ultra-low dielectric constant (Dk < 3.5), ultra-low dielectric loss (Df < 0.002), high peel strength (≥ 0.6 N / mm), and a low Z-axis thermal expansion coefficient (Z-CTE ≤ 1.8%). This CCL has been certified by companies such as Huawei and ZTE and is suitable for high-frequency applications such as 5G base station antenna boards and server motherboards. Its overall performance surpasses that of similar products such as Rogers RO4350B.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low dielectric resin glue for high-frequency and high-speed copper-clad laminates, characterized in that: The composition comprises the following components in parts by weight: Resin component 100 parts, compatibilizer 2-4 parts, curing system 2.5-4.5 parts, initiator 0.6-1.3 parts, filler 55-80 parts, additive 1.1-2.3 parts; The resin components include 25-35 parts of polybutadiene styrene resin, 20-30 parts of ethylene-norbornene copolymer, 30-40 parts of polyimide and 25-35 parts of terminal allyl-modified polyphenylene ether; the allyl substitution degree of the terminal allyl-modified polyphenylene ether is ≥90%; the compatibilizer is maleic anhydride; the curing system includes 1.5-2.5 parts of triallyl isocyanurate and 1-2 parts of triallyl cyanurate; the auxiliary agents include 1-2 parts of a coupling agent and 0.1-0.3 parts of a leveling agent.

2. The low dielectric resin glue for high-frequency and high-speed copper-clad laminate according to claim 1, characterized in that: The initiator comprises 0.1-1.0 parts of dicumyl peroxide and 0.2-1.0 parts of diallyl phthalate.

3. The low dielectric resin glue for high-frequency and high-speed copper-clad laminate according to claim 1, characterized in that: The filler comprises 10-15 parts of DOPO flame retardant, 30-40 parts of spherical silica, and 15-25 parts of angular silica.

4. The low dielectric resin adhesive for high-frequency and high-speed copper-clad laminate according to claim 1, characterized in that: The polystyrene-butadiene resin has a styrene content of 45%-55%, the ethylene-norbornene copolymer has a 5-ethylidene norbornene content of 10%-15%, and the polyimide has an intrinsic viscosity of 0.5-0.7 dL / g.

5. The low dielectric resin glue for high-frequency and high-speed copper-clad laminate according to claim 1, characterized in that: The terminal allyl modified polyphenylene ether is a 2,6-dimethyl polyphenylene ether terminated with a difunctional acrylic acid.

6. A method for preparing a low dielectric resin adhesive for high-frequency and high-speed copper-clad laminates according to any one of claims 1 to 5, characterized in that: The steps include: Step 1, resin premixing and compatibilization: melt-mixing polybutadiene styrene resin and ethylene-norbornene copolymer at 80-100° C. for 30-60 minutes, then adding polyimide and terminal allyl-modified polyphenylene ether; stirring at 500-1000 rpm for 2-3 hours under nitrogen protection; heating to 100-120° C., adding a compatibilizer, and extruding through a twin-screw extruder to generate a graft copolymer matrix; Step 2, filler pretreatment: dry-mix the filler and the coupling agent in a mixer at a rotation speed of 1000-2000 rpm for 15-30 minutes, and then treat in an oven at 120-150°C for 1-3 hours to form a siloxane coating layer to obtain a pretreated filler; Step 3, gradient mixing and initiator dispersion: The graft copolymer matrix produced in step 1 is cooled to 70-80°C, and the curing system, initiator, and leveling agent are added in sequence. After stirring for 15-45 minutes, the pretreated filler obtained in step 2 is added in four batches, with an interval of 5-15 minutes between each batch, to finally obtain a mixed solution with a viscosity controlled at 2500-3500 cps; Step 4: Vacuum degassing: ultrasonically degas the mixture under vacuum for 30-60 minutes to obtain a low dielectric resin adhesive for high-frequency and high-speed copper clad laminates.

7. The method for preparing a low dielectric resin adhesive for high-frequency and high-speed copper-clad laminate according to claim 6, wherein: The temperature of the twin-screw extruder is 120-140° C., and the screw speed is 200-300 rpm.

8. A high-frequency and high-speed copper-clad laminate, characterized in that: The high-frequency and high-speed copper-clad laminate is prepared using the low-dielectric resin adhesive for the high-frequency and high-speed copper-clad laminate as described in any one of claims 1 to 5.

9. The high-frequency and high-speed copper-clad laminate according to claim 8, characterized in that: The preparation method comprises the following steps: Apply the resin glue liquid on the electric glass fiber cloth, controlling the glue content to 60-80%; then cover it with copper foil and cure it in a hot press: the temperature of the first stage is 90-110℃, the time is 10-80min; the temperature of the second stage is 120-180℃, the time is 10-80min; the temperature of the third stage is 180-210℃, the time is 20-40min.

10. The high-frequency and high-speed copper-clad laminate according to claim 9, characterized in that: The copper foil is HVLP copper foil with a roughness Rz≤1.5 μm.

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