CN1121942C - Composite base laminated board covered with copper foil and its production method - Google Patents

Abstract

A kind of manufacturing method of composite base copper-clad laminate of the present invention, its impregnating agent (A) is composed of: bisphenol A type epoxy resin, phenolic type epoxy resin, dicyandiamide, 2-ethyl-4 methylimidazole , ammonium cyanurate, aluminum hydroxide, silicone dispersant, epoxy silane coupling agent and solvent; impregnating agent (B) composition: bisphenol A type epoxy resin, novolac type epoxy resin, thermoplastic Phenolic resin, 2-ethyl-4 methylimidazole, ammonium cyanurate, ammonium polyphosphate, aluminum hydroxide, magnesium hydroxide, silicone dispersant, epoxy silane coupling agent and solvent. Is a "green" flame retardant grade CEM-3.

Description

A kind of manufacturing method of composite base copper clad laminate

Technical Field The present invention relates to a method for manufacturing a composite-based copper-clad laminate for printed circuit boards, especially for the outer layer made of glass fiber cloth/epoxy resin composite material and the inner layer made of glass fiber non-woven fabric/ The impregnating agent formula of the composite-based copper-clad laminate composed of epoxy resin composite materials is improved to make it an environmentally friendly "green" flame-retardant composite-based copper-clad laminate.

Background Art Printed circuit boards are the most basic carrier of electronic product components, and copper-clad laminates are the most basic materials for manufacturing printed circuit boards. At present, the standards and naming of copper-clad laminates for civilian use in the world are formulated by the National Electrical Manufacturers Association (NEMA) under the American National Institute of Standards (ANSI), and have passed the safety testing certification of the United States Underwriters Association (UL). Can be applied to electronic and electrical products. At present, copper-clad laminates are distinguished by materials, mainly: phenolic resin/paper-based copper-clad laminates (FR-1, FR-2), epoxy resin/glass fiber cloth-based copper-clad laminates (FR-2) -4), composite base copper clad laminate (CEM-1, CEM-3). At present, CEM-3 has been applied in mobile communication telephones, mobile communication base stations, telephone program-controlled switches, GSM equipment and civilian satellite communication equipment and other fields. Composite base copper clad laminates are copper clad laminates containing two or more types of different reinforcing materials. CEM-3 is a composite matrix copper clad laminate composed of glass fiber cloth/epoxy resin composite material on the outer layer and glass fiber non-woven fabric/epoxy resin composite material on the inner layer.

The main production process of CEM-3 is: preparation of impregnating agent→impregnation and gluing→drying prepreg→prepreg slicing→copper foil and surface prepreg and core prepreg board matching→vacuum hot pressing→cutting→finished product. The four most important properties of composite-based copper clad laminates are electrical properties, flame retardancy, heat resistance and mechanical properties. The flame retardancy of ordinary flame-retardant composite-based copper-clad laminates is achieved by adjusting the formula of the impregnating agent for the copper-clad laminate prepreg. It is relatively easy to achieve the flame retardant standard of UL94 V-0 for phenolic resin type copper clad laminates. The main reason is that the requirements for heat resistance of phenolic resin type copper clad laminates are not too high. The glass transition temperature (Tg) has requirements, so the flame retardancy of copper clad laminates can meet UL standards by adding various organic flame retardants. According to NEMA regulations, in order to meet the requirements of heat resistance, CEM-3 must have a Tg greater than 130°C; the flame retardancy must meet the standard requirements of UL94 V-0, and only the curing system using tetrabromobisphenol A epoxy resin In order to meet the heat resistance and flame retardancy of CEM-3 at the same time, most of the curing agent also use bromine compounds. For example: use tetrabromobisphenol A (TBBPA). In the article "PCB Base Material - Copper Clad Laminate Technology" (Printed Circuit Information, Issue 9, P32～P37, 1997), the current composite base copper clad laminate technology is introduced. The article points out that the technology used in CEM-3 In the resin formulation components, a flame-retardant brominated epoxy resin is used. In order to improve the heat resistance and moisture resistance of the board, a small amount of other epoxy resins are added for modification. These resins include: multifunctional epoxy resins, ester-containing epoxy resins, ether-based epoxy resins and epoxy resin curing agents (generally dicyandiamide, thermoplastic phenolic resins, etc.), catalysts (generally benzyldimethylamine or imidazoles). There are also flame retardants (such as tetrabromobisphenol A) and flame retardant synergists (such as antimony trioxide) in the resin formulation components. In order to ensure the dimensional stability of copper-clad laminates, about 30% of inorganic fillers should be added to the resin formulation. Generally added fillers are: aluminum hydroxide, calcium carbonate, silicon dioxide, etc. The addition of fillers is also beneficial to improve the metal ion migration resistance, heat resistance, leakage resistance, flame retardancy and punching processability of the board. Flame retardantB-staged epoxy resin prepregs and laminates made therefrom (US Patent No. 4,501,787) discloses the use of bromine-free epoxy resins and bromine-containing flame retardants. Flame-retarded copper clad laminates (US Pat. No. 4,486,505) disclose the use of bromine-containing unsaturated resins. Ordinary CEM-3 contains halogen elements such as bromine or antimony trioxide.

As the basic material of electronic and electrical products, copper-clad laminates are still troubled by manufacturers due to environmental protection issues involved in their processing and use. The main reasons are: (1) Copper-clad laminates must meet UL flame-retardant standards, and the flame-retardant materials used contain halogen elements such as chlorine and bromine and toxic substances such as antimony trioxide. When a fire occurs, the product will release A large amount of toxic gas is emitted, and the amount of smoke is extremely large. (2) In the process of manufacturing printed circuit boards, there is a process of immersing the copper-clad laminate in a solder bath at 250 ° C, so that the printed circuit boards are hung with solder and soldered with components; this process is usually due to Copper-clad laminates are affected by high temperature and release a small amount of bromine, which is harmful to the health of operating workers. (3) After the electrical products are scrapped, the discarded printed circuit boards will bring troubles to recycling and utilization, and cause pollution and harm to the environment. Research and development of environmentally friendly "green" CEM-3 has very important environmental protection significance. UL defines the environmentally friendly "green" flame retardant grade CEM-3 (GREEN CEM-3) as "Holegen Antimony Free", that is, the "green" flame retardant grade CEM-3 cannot contain any chlorine, bromine and other halogen elements and Antimony trioxide. At present, the components of ordinary CEM-3 do not meet the requirements of "green" flame retardant grade CEM-3. Manufacturers have successively researched and developed new resin curing systems to meet the requirements of the "green" flame retardant grade CEM-3.

At present, the development of "green" flame retardant grade CEM-3 in Japan is progressing rapidly. For example, the new Kobe Electric "green" CEM-3 product claims that its resin does not contain bromine-antimony flame retardants. There is no public report about the composition formula of "green" CEM-3. SUMMARY OF THE INVENTION The purpose of the present invention - a method for manufacturing a composite base copper-clad laminate is to propose an environmentally friendly "green" flame-retardant grade CEM-3 composite base copper-clad laminate preparation method. It is the impregnating agent formula of CEM-3 which is composed of glass fiber cloth/epoxy resin composite material on the outer layer and glass fiber non-woven fabric/epoxy resin composite material on the inner layer. Meet the performance requirements of copper clad laminates, and meet the flame retardant standard of UL94 V-0 in the United States, and meet the requirements of "green" flame retardant CEM-3 without chlorine, bromine and other halogen elements and antimony trioxide , can reduce the production and use of harmful substances to people and the environment, and is also conducive to the recycling of waste CEM-3.

The invention improves the formula of the impregnating agent for the surface prepreg and the core layer prepreg of the CEM-3 composite base copper-clad laminate. The resin of impregnating agent (A) is bisphenol A type epoxy resin and novolac type epoxy resin; Catalyst is 2-ethyl-4-methylimidazole; Add flame retardant and dispersion agent in impregnating agent (A), The flame retardant is ammonium cyanurate and aluminum hydroxide in two particle size ranges, and the dispersant is a silicone dispersant; the composition and parts by weight of the impregnating agent (A):

Resin: Bisphenol A epoxy resin 100

                                                                                                                                                   &#;

Curing agent: dicyandiamide 2.2～2.4;

  Flame retardant:   melamine cyanurate   3～5

Aluminum hydroxide

        Particle size 0.8～1.2μm  70～90

Grain size 10～20μm 10～30;

Catalyst: 2-ethyl-4-methylimidazole 0.15～0.2;

Coupling agent: epoxy silane 0.5～1;

Dispersant: Silicone dispersant 0.2～0.3;

Solvent: methyl cellosolve 50～60;

Dimethylformamide 40～50;

The resin of the impregnating agent (B) is bisphenol A epoxy resin and novolac epoxy resin; the curing agent is thermoplastic phenolic resin; the catalyst is 2-ethyl-4-methylimidazole; Flame retardant and dispersant, flame retardant is ammonium cyanurate, ammonium polyphosphate, aluminum hydroxide and magnesium hydroxide in two particle size ranges, dispersant is silicone dispersant; impregnating agent (B) Composition and parts by weight:

Resin: bisphenol A epoxy resin 100

                                        40-55;

Curing agent: thermoplastic phenolic resin 60～85;

  Flame retardant: melamine ammonium cyanurate 10～15

                                                                                                           

Aluminum hydroxide

Grain size 0.8～1.2μm 100～125

Particle size 10～20μm 75～90;

Magnesium hydroxide 0～30;

Catalyst: 2-ethyl-4 methylimidazole 0.5～1;

Coupling agent: epoxy silane 1.5～2.5;

Dispersant: Silicone dispersant 1～2;

Solvent: Methyl Cellosolve 60～80

Acetone 20-40.

The epoxy equivalent of the bisphenol A type epoxy resin in the impregnating agent (A) is 450-500 g/eq, and the epoxy equivalent of the novolak type epoxy resin is 190-220 g/eq.

The epoxy equivalent of the bisphenol A type epoxy resin of the impregnating agent (B) is 190-203 g/eq, and the epoxy equivalent of the novolak type epoxy resin is 190-220 g/eq.

The process parameters for making the surface prepreg with the impregnating agent (A) are: gel time 180-220 seconds, drying temperature 170±2°C, and drying time 210-250 seconds.

The process parameters for making the core prepreg with the impregnating agent (B) are: gel time 90-120 seconds, drying temperature 170±2°C, and drying time 240-300 seconds.

The formula of surface prepreg impregnating agent (A) provided by the present invention does not adopt tetrabromobisphenol A type epoxy resin; And adopt the bisphenol A type epoxy resin of epoxy equivalent 450～500g/eq and epoxy equivalent 190～220g /eq phenolic epoxy resin, the curing agent is dicyandiamide and ammonium cyanurate is used as the flame retardant. The purpose is to increase the crosslinking density of the curing system and introduce a large amount of Nitrogen, so as to ensure the heat resistance of "green" CEM-3, but also improve the flame retardancy of "green" CEM-3. Use aluminum hydroxide with flame retardant properties in two particle size ranges that have been treated by ordinary drying methods: coarse particle size (10-20μm) aluminum hydroxide can improve the rheological properties of the semi-cured resin and improve the adhesion of the prepreg. Aluminum hydroxide with ultra-fine particle size (0.8～1.2μm) can ensure the flame retardant performance of "green" CEM-3, and aluminum hydroxide can reduce the water absorption of copper-clad laminates after drying treatment, thereby improving "green" CEM-3 -3 electrical insulation. Add epoxy resins with different functionalities to the formula, and adjust the crosslinking density of the curing system by adjusting the ratio of them to the main resin, so that the electrical breakdown performance of the "green" CEM-3 under humidity conditions—— Contrast trace index (CTI) reaches 600V voltage resistance.

The formula of the impregnating agent (B) of the core prepreg provided by the present invention adopts the epoxy resin of multi-epoxy functional group, for example adopts the bisphenol A type epoxy resin of epoxy equivalent 190～203g/eq and epoxy equivalent 190～220g/eq Novolac type epoxy resin, and thermoplastic phenolic resin as curing agent; using flame retardant cyanuric ammonium cyanurate, ammonium polyphosphate, aluminum hydroxide and magnesium hydroxide, magnesium hydroxide can improve flame retardancy The synergistic effect and cohesiveness of the flame retardant aluminum hydroxide in two particle size ranges that have been treated by ordinary drying methods: aluminum hydroxide with a coarse particle size (10-20 μm) can improve the rheology of the semi-cured resin. The adhesion of the prepreg is good, and the aluminum hydroxide with ultra-fine particle size (0.8-1.2μm) can ensure the flame retardancy of "green" CEM-3, and the drying treatment of aluminum hydroxide can reduce the flame retardancy of "green" CEM-3. Water absorption, thereby improving the electrical insulation of "green" CEM-3. The above measures strengthen the adhesion and compatibility between the filler and the resin, and at the same time increase the crosslinking density of the inner composite layer curing system, ensuring that the "green" CEM-3 inner layer composite layer has high Tg and low thermal shrinkage. Because the amount of inorganic flame retardant added in the impregnating agent formula of the present invention is more, can cause curing speed to descend, so the present invention adopts high-efficiency coupling agent (for example: epoxy silane) and organosilicon dispersant (for example: commercially available German BYK company's W940 dispersant), so that the curing system can ensure that the composite material has excellent flame retardancy without reducing heat resistance and mechanical properties without bromine and antimony trioxide, and makes the surface The peel strength between the composite layer and the copper foil will not decrease excessively. The present invention improves the impregnating agent formula of the facing prepreg and the core prepreg, adopts raw materials that do not contain halogen elements such as chlorine and bromine, and antimony trioxide and other harmful substances, and makes the copper-clad laminates produced as a whole ensure "green" "The flame retardancy, electrical properties, mechanical properties and heat resistance properties of CEM-3 can be coordinated and improved.

The production of prepreg is a very important process in the production process of CEM-3, which directly affects the various properties of copper clad laminates. Due to the change of the impregnating agent formula of "green" CEM-3, its process conditions and performance parameters will change accordingly. The processing parameters of the impregnating agent (A) of the present invention for making surface prepregs are: using a catalyst to adjust the gel time to 180-220 seconds, drying temperature: 170±2°C, and drying time: 200-250 seconds. The physical parameters of the prepared surface prepreg: surface prepreg (impregnated with 7628 type glass fiber cloth) weight: 18.5±0.5 g/(4×16 square inches), resin fluidity 15～20%, EIC gel time 300～ 350 seconds, minimum viscosity 20-30 centipoise. The processing technology of the impregnating agent (B) when it is used to make the core prepreg: use a catalyst to adjust the gel time to 90-120 seconds, the drying temperature: 170±2°C, and the drying time: 240-300 seconds. The physical parameters of the core prepreg made: core prepreg (impregnated with 85 grams of glass fiber non-woven fabric) weight: 25.0 ± 0.5 grams/(4 * 16 square inches), resin fluidity 18～20%. Example:

The formulation, process conditions and performance parameters of the surface prepreg impregnating agent (A) of the composite base copper-clad laminate proposed by the present invention are shown in Examples 1 to 6 in Table 1.

Examples of the formulation, process conditions and performance parameters of the core prepreg impregnating agent (B) of the composite-based copper-clad laminate proposed by the present invention are shown in Examples 1 to 6 in Table 2.

Adopt 7628 type glass fiber cloth with the formula of embodiment 1～embodiment 6 shown in table 1 and process the face prepreg that processing is made, and adopt the embodiment 1～execution shown in table 2 of 85 gram type glass fiber non-woven fabrics The core prepreg processed by the formula and process conditions of Example 6, the surface is matched with a copper foil board with a specification of 1 ounce, the second-layer prepreg and the middle three-layer core prepreg are matched with a board, and are cured by vacuum hot pressing to obtain a specification of 1.6 mm. Thick "green" CEM-3 composite-based copper-clad laminates, its performance: flame retardancy reaches UL94 VO level; 260 ° C dip soldering resistance ≥ 140 seconds; insulation resistance ≥ 1 × 10 ¹³ Ω; thermomechanical analysis (TMA ) Tg≥130°C; thermal mechanical analysis (TMA) expansion rate≤3.5%; contrast trace index CTI reaches 600V. Comparing the performance of "green" CEM-3 of the present invention with ordinary CEM-3, the "green" CEM-3 of the present invention not only reaches or exceeds CEM-3 in important properties such as flame retardancy, electrical properties, mechanical properties and heat resistance. 3 performance indicators, and because the composition of the impregnating agent does not contain chlorine, bromine and other halogen elements and antimony trioxide, it can reduce the harmful gas in the manufacturing process of composite base copper clad laminates and the production process of printed circuit boards. The health damage of operators can also reduce the occurrence of fire accidents, avoid the harm of toxic gases to electrical users, and also facilitate the recycling of discarded printed circuit boards. The invention is an environment-friendly "green" flame-retardant grade composite base copper-clad laminate.

Table 1 Surface prepreg impregnating agent formula and process conditions of the present invention name Weight (parts) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 raw material Bisphenol A type epoxy resin 100 100 100 100 100 100 100 Novolac epoxy resin 0～10 0 10 7 10 5 8 Dicyandiamide 2.2～2.4 2.2 2.4 2.2 2.3 2.3 2.2 Ammonium cyanurate 3～5 3 5 3 4 5 5 Ultrafine Aluminum Hydroxide 70～90 80 85 90 75 85 70 Coarse particle size aluminum hydroxide 10～30 20 25 15 30 10 25 2Ethyl-4methylimidazole 0.15～0.2 0.15 0.2 0.15 0.17 0.15 0.15 Epoxy silane coupling agent 0.5～1.0 0.6 0.6 0.5 0.7 0.7 1.0 BYK-W940 Dispersant 0.2～0.3 0.2 0.3 0.2 0.25 0.2 0.2 methyl cellosolve 50～60 50 60 50 50 55 50 dimethylformamide 40～50 50 40 50 50 45 50 Process conditions and parameters Gel time: 180～220(sec.) 180 216 205 191 196 219 Drying temperature: 170±2(℃) 170 170 170 170 170 170 Drying time: 200～250(sec.) 230 220 200 240 250 210 Prepreg weight: 18.5±0.5(g) 18.5 18.5 18.8 18.7 18.6 18.1 Resin fluidity: 15～20(%) 16.8 19.5 17.7 18.3 15.6 15.3 EIC gel time: 300～350(sec.) 312 340 300 325 350 319 Minimum Viscosity: 20～30(cp) 25 29 20 twenty three twenty three 30

Note: ^* The particle size is 0.8～1.0μm, ^** The particle size is 10～20μm.

Table 2 core prepreg impregnating agent formulation and process conditions of the present invention effect raw material Weight (parts) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 raw material Bisphenol A type epoxy resin 100 100 100 100 100 100 100 Novolac epoxy resin 40～55 40 40 55 40 50 55 thermoplastic phenolic resin 60～85 60 80 85 70 70 65 Ammonium cyanurate 10～15 10 10 15 10 13 15 Ammonium polyphosphate 20～25 twenty two twenty three 25 20 twenty three 25 Ultrafine Aluminum Hydroxide* 100～125 100 110 125 105 120 125 Coarse particle size aluminum hydroxide** 75～90 75 80 90 80 85 90 magnesium hydroxide 0～30 15 30 0 20 25 5 2Ethyl-4methylimidazole 0.5～1.0 0.5 0.5 0.7 0.5 1.0 1.0 Epoxy silane coupling agent 1.5～2.5 1.5 2.0 2.5 2.0 2.0 2.5 BYK-W940 Dispersant 1.0～2.0 1.0 1.5 2.0 1.5 2.0 2.0 methyl cellosolve 60～80 70 80 60 65 75 60 acetone 20～40 30 20 35 25 30 40 Process parameters Gel time: 90～120(sec.) 98 90 114 109 110 118 Drying temperature: 170±2(℃) 170 170 170 170 170 170 Drying time: 240～300(sec.) 250 270 260 240 300 290 Prepreg weight: 25.0±0.5(g) 25.2 25.5 25.1 24.9 25.4 25.5 Resin fluidity: 18～20(%) 18.2 19.4 19.6 18.7 19.7 18.4

Note: ^* The particle size is 0.8～1.0μm, ^** The particle size is 10～20μm.

Claims (5)

1, a kind of manufacture method that is used for the composite base laminated board covered with copper foil of printed circuit board (PCB) is that glass cloth is made the face prepreg through dipping gluing, dry semi-solid preparation; Through dipping gluing, dry semi-solid preparation, be made for the core prepreg with the glass nonwoven fabrics; Copper Foil and face prepreg, core prepreg are made composite base laminated board covered with copper foil through vacuum hotpressing, the impregnating agent (A) that is used for the machined surface prepreg is by resin, curing agent, fire retardant, catalyst, coupling agent and solvent composition, the impregnating agent (B) that is used for the core prepreg is by resin, curing agent, fire retardant, filler, catalyst, coupling agent and solvent composition

It is characterized in that: the resin of (1) impregnating agent (A) is bisphenol A type epoxy resin and phenol aldehyde type epoxy resin; Catalyst is a 2-ethyl-4-methylimidazole; Be added with fire retardant and dispersant in the impregnating agent (A), fire retardant is the aluminium hydroxide of cyanuric acid melamine and two kinds of particle size ranges, and dispersant is the organosilicon dispersant; The composition and the parts by weight of impregnating agent (A):

Resin: bisphenol A type epoxy resin 100

Phenol aldehyde type epoxy resin 0～10;

Curing agent: dicyandiamide 2.2～2.4;

Fire retardant: cyanuric acid melamine 3～5

Aluminium hydroxide

Granularity 0.8～1.2 μ m 70～90

Granularity 10～20 μ m 10～30;

Catalyst: 2-ethyl-4-methylimidazole 0.15～0.2;

Coupling agent: epoxy silane 0.5～1;

Dispersant: organosilicon dispersant 0.2～0.3;

Solvent: methyl cellosolve 50～60;

Dimethyl formamide 40～50; (2) resin of impregnating agent (B) is bisphenol A epoxide resin and phenol aldehyde type epoxy resin; Curing agent is a novolac resin; Catalyst is a 2-ethyl-4-methylimidazole; Be added with fire retardant and dispersant in the impregnating agent (B), fire retardant is the aluminium hydroxide and the magnesium hydroxide of cyanuric acid melamine, APP, two kinds of particle size ranges, and dispersant is the organosilicon dispersant; The composition and the parts by weight of impregnating agent (B):

Resin: bisphenol A type epoxy resin 100

Phenol aldehyde type epoxy resin 40～55;

Curing agent: novolac resin 60～85;

Fire retardant: cyanuric acid melamine 10～15

APP 20～25

Aluminium hydroxide

Granularity 0.8～1.2 μ m 100～125

Granularity 10～20 μ m 75～90;

Magnesium hydroxide 0～30;

Catalyst: 2-ethyl-4 methylimidazole 0.5～1;

Coupling agent: epoxy silane 1.5～2.5;

Dispersant: organosilicon dispersant 1～2;

Solvent: methyl cellosolve 60～80

Acetone 20～40.

2, the manufacture method of composite base laminated board covered with copper foil according to claim 1 is characterized in that: the epoxide equivalent of the bisphenol A type epoxy resin of impregnating agent (A) is 450～500g/eq, and the phenol aldehyde type epoxy resin epoxide equivalent is 190～220g/eq.

3, the manufacture method of composite base laminated board covered with copper foil according to claim 1 is characterized in that: the epoxide equivalent of the bisphenol A type epoxy resin of impregnating agent (B) is 190～203g/eq, and the phenol aldehyde type epoxy resin epoxide equivalent is 190～220g/eq.

4, the manufacture method of composite base laminated board covered with copper foil according to claim 1 is characterized in that: the technological parameter that impregnating agent (A) is made the face prepreg is: gel time 180～220 seconds, 170 ± 2 ℃ of baking temperatures, 210～250 seconds drying times.

5, the manufacture method of composite base laminated board covered with copper foil according to claim 1 is characterized in that: the technological parameter that impregnating agent (B) is made the core prepreg is: gel time 90～120 seconds, 170 ± 2 ℃ of baking temperatures, 240～300 seconds drying times.