High-speed high-frequency low-CTE copper-clad plate glue solution as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of copper-clad plate materials, and relates to a high-speed high-frequency low-CTE copper-clad plate glue solution as well as a preparation method and application thereof, the copper-clad plate glue solution comprises 55-135 parts of a resin composition, 2.5-21 parts of a cross-linking agent, 0.05-1.5 parts of a cross-linking accelerant, 11-54 parts of filler and 38-95 parts of a solvent; the resin composition is prepared from 25 to 45 parts of polyerylene resin, 15 to 35 parts of styrene-butadiene polymer, 15 to 30 parts of bismaleimide and 10 to 25 parts of allyl-terminated polyphenyl ether resin. According to the invention, Dk and Df meet the requirement of ultra-low loss and are greatly improved compared with the traditional PPO system, and meanwhile, the Z-axis CTE is reduced by more than 40%; the halogen-free flame-retardant design meets the environment-friendly requirement, and the high-frequency performance is not influenced; and a standard PCB processing technology is compatible, and the copper-clad plate suitable for 5G millimeter wave communication, automatic driving radar and satellite high-frequency circuits is prepared.

Description

Technical Field

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

[0002] Existing high-frequency copper clad laminates mostly use polytetrafluoroethylene (PTFE) or modified epoxy resin systems, but they have the following defects: 1. PTFE has poor processability and high CTE (>70 ppm), which can easily lead to cracking between layers of multilayer boards; 2. The dielectric loss of epoxy resin systems (Df>0.005) cannot meet the requirements of the millimeter wave band; 3. Traditional brominated flame retardants will degrade dielectric properties and do not meet environmental requirements.

[0003] Therefore, a copper clad laminate adhesive and a preparation process that can solve the above problems are needed. Summary of the Invention

[0004] In response to the deficiencies in the above-mentioned prior art, the present invention provides a high-speed, high-frequency, low-CTE copper clad laminate adhesive, and a preparation method and application thereof. The copper clad laminate adhesive is a copper clad laminate adhesive that has low dielectric loss, low coefficient of thermal expansion (CTE), and high heat resistance and reliability. The specific technical solution is as follows: The first object of the present invention is to provide a high-speed, high-frequency, low CTE copper clad laminate adhesive, comprising the following components in parts by weight: 60-135 parts of resin composition, 2.5-21 parts of crosslinking agent, 0.05-1.5 parts of crosslinking accelerator, 11-54 parts of filler, and 38-95 parts of solvent; The resin composition comprises 25-45 parts of polyurethane resin, 15-35 parts of styrene-butadiene polymer, 15-30 parts of bismaleimide (BMI) and 10-25 parts of terminal allyl polyphenylene ether (PPO) resin.

[0005] In the resin system used in the present invention, the low polarity main chain of the polyurethane resin can reduce the dielectric constant (Dk); the terminal allyl PPO resin is cross-linked with BMI through the allyl group to improve heat resistance and maintain a low Df; bismaleimide (BMI): forms a highly cross-linked network with TAIC / TAC to ensure T288>120 minutes.

[0006] Furthermore, the terminal allyl polyphenylene ether resin is a difunctional acrylic acid-terminated 2,6-dimethyl polyphenylene ether, such as SA9000 from Saudi Arabia.

[0007] Furthermore, the cross-linking agent is one or both of triallyl isocyanurate (TAIC) and triallyl cyanurate (TAC).

[0008] The TAC and TAIC used in the present invention have the effects of inhibiting and retarding the polymerization of hydrocarbon resins and can easily form graft copolymers with PPO.

[0009] Furthermore, the cross-linking accelerator is a mixture of diallyl phthalate (DAP) and an imidazole compound, and the mass ratio of the diallyl phthalate (DAP) to the imidazole compound is 1:0.2-0.8.

[0010] The DAP used in the present invention is used to inhibit polymerization, slow polymerization, extend the chain and cross-link, and the imidazole compound is used to promote the solidification of bismaleimide in the composition.

[0011] Furthermore, the filler is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), silicon dioxide and ceramic powder, and the mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), silicon dioxide and ceramic powder is (30~50):(40~60):(5~15).

[0012] The present invention adopts functional filler compounding, and DOPO is a reactive halogen-free flame retardant, which provides flame retardant properties and avoids affecting dielectric properties; Silicon dioxide reduces both CTE and dielectric loss; ceramic powder regulates the thermal expansion coefficient and enhances high-frequency stability while reducing CTE and dielectric loss. Furthermore, the solvent is a mixed solvent of toluene and butanone, and the mass ratio of toluene to butanone is 6:4~4:6.

[0013] Furthermore, the allyl content of the terminal allyl PPO resin is 2-5%, and the molecular weight is 5000-15000 g / mol.

[0014] Furthermore, the silicon dioxide has a spherical hollow structure with a particle size of 0.5-5 μm. The hollow silicon dioxide reduces the dielectric constant and the Z-axis CTE.

[0015] Furthermore, the ceramic powder is barium strontium titanate (BST) or boron nitride (BN), and has a particle size of ≤2 μm.

[0016] Furthermore, the polyurethane resin is a hydrogenated polybutadiene-styrene copolymer with a styrene content of 20-40%.

[0017] Furthermore, the structural formula of the polyurethane resin is shown in formula (1):

[0018] Formula (1).

[0019] A second object of the present invention is to provide a method for preparing the above-mentioned high-speed, high-frequency, low-CTE copper clad laminate adhesive, comprising the following steps: dissolving the resin composition in a solvent, stirring at 40-50°C until completely dissolved, then sequentially adding a crosslinking agent, a filler, and a crosslinking accelerator, and ultrasonically dispersing for 30-60 minutes to form a uniform copper clad laminate adhesive, wherein the viscosity of the copper clad laminate adhesive is controlled to be 1500-3000 mPa·s.

[0020] The third object of the present invention is to provide a high-speed, high-frequency, low-CTE copper clad laminate, which is prepared using the above-mentioned high-speed, high-frequency, low-CTE copper clad laminate glue.

[0021] Furthermore, the method for preparing the high-speed, high-frequency, low-CTE copper clad laminate comprises the following steps: Step 1, coating and drying: Apply the high-speed, high-frequency, low-CTE copper-clad laminate adhesive on the glass fiber cloth, control the adhesive content to 60-80%, and dry it at 120-150°C for 200-400 seconds to obtain a prepreg; Step 2: Lamination and curing: Cover multiple prepregs with copper foil and heat them in a vacuum laminator at a gradient of 0.5-10°C / min for segmented curing. The first stage: the temperature is 80~120℃, the pressure is 1 MPa, and the time is 20~40 minutes to achieve solvent evaporation and pre-crosslinking; The second stage: temperature 160~180℃, pressure 2 MPa, time 50~70 minutes, to promote the main cross-linking reaction; The third stage: temperature is 200~250℃, pressure is 3 MPa, and time is 100~140 minutes to complete densification and interface bonding.

[0022] The present invention adopts gradient pressing and curing, segmented temperature increase and pressure control to suppress micro cracks and improve interface bonding strength.

[0023] Furthermore, the glass fiber cloth is D1078 glass fiber cloth.

[0024] Furthermore, the copper foil is an extremely low-profile copper foil with Rz ≤ 18 μm, which reduces skin effect loss in signal transmission.

[0025] The beneficial effects of the present invention are: The present invention achieves Dk and Df that meet ultra-low loss requirements through the collaboration of a polarity-adjustable resin system and functional fillers, which is a significant improvement over traditional PPO systems. At the same time, the Z-axis CTE is reduced by more than 40%. The halogen-free flame-retardant design meets environmental protection requirements without affecting high-frequency performance. Compatible with standard PCB processing technology, the prepared high-frequency, high-speed copper-clad laminate is suitable for 77 GHz automotive radars and 28 GHz 5G Massive MIMO antennas, and is suitable for 5G millimeter-wave communications, autonomous driving radars, and satellite high-frequency circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the laminated structure of the copper clad laminate of the present invention. DETAILED DESCRIPTION

[0027] 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.

[0028] Example 1: A high-speed, high-frequency, low-CTE copper-clad laminate comprises the following preparation steps: Step 1, glue solution preparation: dissolve the resin composition in the solvent, stir at 45 ° C until completely dissolved, then add the crosslinking agent, filler and crosslinking accelerator in sequence, and disperse by ultrasonic for 50 minutes to form a uniform copper clad laminate glue with a viscosity controlled at 2000 mPa·s; In parts by weight, the resin composition comprises 35 parts of polyurethane resin (as shown in formula (1)), 25 parts of styrene-butadiene polymer (RICON-100 from Crayville), 20 parts of BMI (9400 from Tongyu), and 20 parts of terminal allyl PPO (SA9000 from Sabic); The crosslinking agent is 10 parts of TAIC; the crosslinking accelerator is a mixture of 0.6 parts of DAP and 0.3 parts of 2-phenylimidazole; the filler is a mixed filler of 12 parts of DOPO, 25 parts of hollow silica and 5 parts of boron nitride powder; and the solvent is a mixed solvent of 35 parts of toluene and 35 parts of butanone.

[0029] Step 2, coating and drying: Coat the copper clad laminate glue obtained in step 1 on D1078 fiberglass cloth, control the glue content to 70%, and dry at 140°C for 300 seconds to obtain a prepreg; Step 3, pressing and curing: Cover 10 prepregs with very low profile 18-micron copper foil (HVLP), and heat them in a vacuum pressing machine at a gradient of 0.5°C / min for segmented curing: the first stage: temperature of 100°C, pressure of 1 MPa, time of 30 minutes, to achieve solvent volatilization and pre-crosslinking; the second stage: temperature of 170°C, pressure of 2 MPa, time of 60 minutes, to promote the main cross-linking reaction; the third stage: temperature of 210°C, pressure of 3 MPa, time of 120 minutes, to complete densification and interface bonding.

[0030] Example 2: A high-speed, high-frequency, low-CTE copper-clad laminate, wherein the filler in step 1 is 15 parts of DOPO, 20 parts of hollow silica, and 8 parts of barium strontium titanate, and the rest is the same as in Example 1 and will not be repeated here.

[0031] Comparative Example: A copper clad laminate, comprising the following preparation steps: Step 1, glue solution preparation: dissolve the resin composition in the solvent, stir at 45 ° C until completely dissolved, then add the crosslinking agent, filler and crosslinking accelerator in sequence, and ultrasonically disperse for 50 minutes to form a uniform copper clad laminate glue with a viscosity controlled at 2000 mPa·s.

[0032] The resin composition comprises, by weight, 30 parts of cyanate resin, 25 parts of biphenyl epoxy, 20 parts of BMI, and 20 parts of terminal allyl PPO; the crosslinking agent is 15 parts of TAIC; the crosslinking accelerator is a mixture of 0.6 parts of DAP and 0.1 parts of 2-phenylimidazole; the filler is a mixed filler of 12 parts of DOPO, 25 parts of hollow silica, and 5 parts of boron nitride powder; and the solvent is a mixed solvent of 33.25 parts of toluene and 33.25 parts of butanone.

[0033] Step 2, coating and drying: Coat the copper clad laminate glue obtained in step 1 on D1078 fiberglass cloth, control the glue content to 70%, and dry at 140°C for 300 seconds to obtain a prepreg; Step 3, pressing and curing: Cover 10 prepregs with an extremely low-profile 18-micron copper foil, and heat them in a vacuum pressing machine at a gradient of 0.5°C / min for segmented curing: the first stage: the temperature is 100°C, the pressure is 1 MPa, and the time is 30 minutes to achieve solvent volatilization and pre-crosslinking; the second stage: the temperature is 170°C, the pressure is 2 MPa, and the time is 60 minutes to promote the main cross-linking reaction; the third stage: the temperature is 210°C, the pressure is 3 MPa, and the time is 120 minutes to complete densification and interface bonding. The copper clad laminates prepared in the examples and comparative examples were subjected to performance tests, and the test results are shown in Table 1.

[0034] Dielectric properties: IPC TM-650 2.5.5.13 at 10 GHz; Thermal properties: Tg = 210 ° C, TMA method; Mechanical properties: peel strength, 18 μm copper foil, IPC-TM-650 2.4.8; Coefficient of thermal expansion: Z-axis CTE (before Tg), TMA method, IPC TM-650; Welding resistance: 288℃ plug welding, JIS C6481; Flame retardancy: UL94 (0.8 mm thickness).

[0035] Table 1 Performance test table of copper clad laminates prepared in Examples and Comparative Examples

[0036] The present invention prepares a high-speed, high-frequency, low-CTE copper-clad laminate through the synergy of multiple resins, halogen-free flame-retardant fillers and gradient curing process. The heat resistance is: no delamination after 600 seconds of soldering at 288°C, and the T288 delamination time is greater than 120 minutes; mechanical properties: extremely low-profile copper foil (18 μm) peel strength is greater than 0.7 N / mm; thermal expansion coefficient: Z-axis CTE (before Tg) ≤50 ppm / °C; dielectric properties: dielectric constant (Dk) ≤3.0 at 10 GHz, dielectric loss (Df) ≤0.0012; flame retardancy: UL94 FV0 level (0.8 mm thickness), suitable for 77 GHz automotive radar and 28 GHz 5G Massive MIMO antenna, suitable for 5G millimeter wave communication, autonomous driving radar and satellite high-frequency circuits. 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 high-speed, high-frequency, low-CTE copper-clad laminate adhesive, characterized in that: The composition comprises the following components in parts by weight: 60-135 parts of resin composition, 2.5-21 parts of crosslinking agent, 0.05-1.5 parts of crosslinking accelerator, 11-54 parts of filler, and 38-95 parts of solvent; The resin composition comprises 25-45 parts of polyurethane resin, 15-35 parts of styrene-butadiene polymer, 15-30 parts of bismaleimide and 10-25 parts of terminal allyl polyphenylene ether resin.

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

3. The high-speed, high-frequency, low-CTE copper clad laminate adhesive according to claim 1, characterized in that: The crosslinking agent is one or both of triallyl isocyanurate and triallyl cyanurate; the crosslinking accelerator is a mixture of diallyl phthalate and an imidazole compound, and the mass ratio of diallyl phthalate to the imidazole compound is 1:0.2~0.

8.

4. The high-speed, high-frequency, low-CTE copper clad laminate adhesive according to claim 1, characterized in that: The filler comprises 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, silicon dioxide and ceramic powder, and the mass ratio of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, silicon dioxide and ceramic powder is (30-50): (40-60): (5-15).

5. The high-speed, high-frequency, low-CTE copper clad laminate adhesive according to claim 1, characterized in that: The solvent is a mixed solvent of toluene and butanone, and the mass ratio of the toluene to butanone is 6:4 to 4:

6.

6. The high-speed, high-frequency, low-CTE copper clad laminate adhesive according to claim 1, characterized in that: The allyl content of the terminal allyl polyphenylene ether resin is 2-5%, and the molecular weight is 5000-15000 g / mol; the polyurethane resin is a hydrogenated polybutadiene-styrene copolymer, and the styrene content is 20-40%.

7. The high-speed, high-frequency, low-CTE copper clad laminate adhesive according to claim 1, characterized in that: The structural formula of the polyurethane resin is shown in formula (1): Formula (1).

8. A method for preparing a high-speed, high-frequency, low-CTE copper clad laminate adhesive according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: dissolving a resin composition in a solvent, stirring at 40-50° C. until completely dissolved, sequentially adding a crosslinking agent, a filler, and a crosslinking accelerator, and ultrasonically dispersing the mixture for 30-60 minutes to form a uniform copper clad laminate adhesive, wherein the viscosity of the copper clad laminate adhesive is controlled to be 1500-3000 mPa·s.

9. A high-speed, high-frequency, low-CTE copper-clad laminate, characterized in that: It is prepared using the high-speed, high-frequency, low-CTE copper clad laminate adhesive as described in any one of claims 1 to 7.

10. The high-speed, high-frequency, low-CTE copper-clad laminate according to claim 9, characterized in that: The preparation method comprises the following steps: Step 1, coating and drying: Apply the high-speed, high-frequency, low-CTE copper-clad laminate adhesive on the glass fiber cloth, control the adhesive content to 60-80%, and dry it at 120-150°C for 200-400 seconds to obtain a prepreg; Step 2: Lamination and curing: Cover multiple prepregs with copper foil and heat them in a vacuum laminator at a gradient of 0.5-10°C / min for segmented curing. The first stage: temperature is 80~120℃, pressure is 1 MPa, and time is 20~40 minutes; The second stage: temperature is 160~180℃, pressure is 2 MPa, and time is 50~70 minutes; The third stage: temperature is 200~250℃, pressure is 3 MPa, and time is 100~140 minutes.

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