JPH048461B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laminate having excellent water resistance, heat resistance, electrical properties, etc. It is well known that currently, epoxy resin-based laminates are mainly manufactured by a method using a combination of an epoxy resin and an amine-based curing agent, but this method is not necessarily satisfactory. For example, when using a low molecular weight, highly reactive epoxy resin, the viscosity of the resin decreases too much when it is cured under heat and pressure, making it easy to flow out, and the resulting laminate becomes hard and brittle, as well as having a high hydroxyl group content. Water absorption becomes high and electrical properties are also insufficient. On the other hand, even if an epoxy resin with high molecular weight and low reactivity is used, the hydroxyl content does not decrease, but rather the crosslinking density has a large effect of decreasing, making it difficult to improve water absorption. In addition, a method has been proposed in which a low molecular weight, highly reactive epoxy resin is used in combination with a modifier such as oil such as tung oil or tung oil fatty acid, or a long chain fatty acid, but in this case, these modifiers may be unreacted. Otherwise, it tends to remain as a long side chain, which tends to cause a decrease in heat resistance. Therefore, the inventors of the present invention have completed the present invention as a result of intensive research aimed at solving the above-mentioned drawbacks and obtaining a laminate with excellent physical properties. That is, the present invention provides a copolymer (A) with an acid value of 80 to 250 obtained as essential components of an aromatic vinyl compound (a) and an unsaturated carboxylic acid (b), and an epoxy resin.
(B) has 0.6 epoxy groups per carboxyl group.
After impregnating a fibrous base material () with a resin liquid () obtained by dissolving it in a solvent (C) at a ratio of ~2.0 pieces, the prepreg obtained by removing the solvent (C),
The present invention relates to a method for manufacturing a laminate, which is characterized by curing under heat and pressure. Aromatic vinyl compounds (a) include, for example, styrene,
Vinyltoluene, (refers to compounds with one vinyl substituent on the aromatic ring such as chlorostyrene, bromustyrene, methylstyrene, vinylpyridine, etc.) Unsaturated carboxylic acid (b) refers to acrylic acid, methacrylic acid, maleic acid , maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, maleic acid monomethyl ester, maleic acid monobutyl ester, maleic acid monocyclohexyl ester, fumaric acid monoethyl ester, fumaric acid monotetrahydrofurfuryl ester, itacon Refers to a polymerizable unsaturated compound having at least one carboxyl group or acid anhydride group such as acid monoethyl ester. Copolymer (A) is at least an aromatic vinyl compound (A)
It is a copolymer having an acid value of 80 to 250, preferably 100 to 200, obtained by copolymerizing two components: and unsaturated carboxylic acid (2). If the acid value is lower than 80, the heat resistance will decrease, and if it is higher than 250, the water absorption will increase, which is not preferable. The copolymer (A) can contain polymerizable monomer components other than the above two components. Examples of such polymerizable monomers include vinyl acetate, allyl alcohol, phenyl allyl ether, acrylic esters, methacrylic esters, and the like. Among these, those having as few hydrophilic groups as possible are preferred, and the amount used is preferably 30% by weight or less based on the copolymer (A). Among the copolymers (A), copolymers (A) containing 50% by weight or more of the aromatic vinyl compound (a) component are particularly preferred from the viewpoint of water resistance and electrical properties; ) is preferably acrylic acid and/or methacrylic acid from the viewpoint of strength. Copolymer (A) can be obtained by polymerizing predetermined monomer components according to conventionally known methods (eg, emulsion polymerization, bulk polymerization, suspension polymerization, solution polymerization, etc.). Among these, solution polymerization using a solvent used as the solvent (C) described later is particularly preferable since there is no need for a step of separating the copolymer (A). However, the copolymer (A) is not limited by its manufacturing method. The epoxy resin (B) refers to a compound containing at least two epoxy groups in one molecule, and compounds called so-called epoxy resins can be effectively used. Such epoxy resins (B) include, for example, Plastic Materials Course 1 "Epoxy Resins" published by Nikkan Kogyo Shimbun (published on May 30, 1960, edited by Kuniyuki Hashimoto), pages 19 to 48, and Stanford.・Report No. 38 “Epoxy Resin (EPOXY)” published by Research Institute (STANFORD RESEARCH INSTITUTE)
RESINS) (published June 1968), pages 25 to 39, can be used. Among them, bisphenol A, bisphenol F, brominated bisphenol A, phenol novolak, brominated phenol novolak, cresol novolak, etc., and epichlorohydrin and/or
Alternatively, epoxy resins derived from 2-methylepichlorohydrin are particularly preferred in terms of physical properties. When used, the epoxy resin (B) contains a monovalent epoxy compound such as phenyl glycidyl ether, epichlorohydrin, glycidyl methacrylate, α-olefin epoxide, styrene oxide, allyl glycidyl ether as a modifying agent in place of a part of the resin. can do. However, the maximum amount of these modifiers used is 15 equivalent% of the total epoxy compound, and when using a modifier, it is necessary to remove the solvent (C) described below to obtain a prepreg. In order to suppress volatilization of the agent as much as possible, it is desirable to fully consider the process conditions and the boiling point of the modifier. The resin liquid () is a copolymer (A) and an epoxy resin (B).
and the carboxyl group 1 contained in the copolymer (A)
(However, one acid anhydride group is considered as two carboxyl groups.) Epoxy resin (B) contains 0.6 to 2.0 epoxy groups dissolved in solvent (C). be. If the proportion of epoxy groups is out of the above range, it is not only unfavorable in terms of strength, but also has an excessive amount of unreacted carboxyl groups.
The curing of the epoxy resin (B) tends to be insufficient, and both are unfavorable. The solvent (C) is preferably one that dissolves both the copolymer (A) and the epoxy resin (B), and more preferably has a boiling point in the range of approximately 40 to 150°C, preferably approximately 50 to 120°C. . Such solvents (C) include:
Solvents conventionally known and used in the resin and paint industries (e.g. hydrocarbons such as cyclohexane, benzene, toluene, xylene; ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetone;
Esters such as ethyl acetate, butyl acetate, lactone; methyl t-butyl ether, dioxane,
Ethers such as tetrahydrofuran; halogenated hydrocarbons such as tricrene, chloroform, methylene chloride, chlorobenzene, etc.)
One or more of these can be appropriately selected and used depending on the type of copolymer (A) and epoxy resin (B). The amount of solvent (C) to be used can be determined by the method of impregnating the resin liquid () into the fibrous base material () or the method of impregnating the resin liquid () with the resin liquid () as described below.
The appropriate amount is selected and used depending on the amount of additives added as necessary, but usually 50 to 100 parts by weight per 100 parts by weight of the total amount of copolymer (A) and epoxy resin (B). In the range of 400 parts by weight. When impregnating the resin liquid () into the fibrous base material (), flame retardant aids such as antimony trioxide and phosphate esters; coloring agents; talc, calcium carbonate, silica powder, etc. are added to the resin liquid (). Fillers represented by: UV absorbers, antioxidants, stabilizers such as halogen trapping agents (e.g. organic acid tin, etc.); various additives such as reaction catalysts such as tertiary amines can be used as appropriate. . As the fibrous base material (), organic or inorganic woven fabric or nonwoven fabric can be used. For example, one or more types can be appropriately selected and used from woven fabrics and non-woven fabrics made of various fibers such as asbestos, glass, polyester, and pulp. Also,
As with conventional techniques, it is also possible to pre-treat these fibrous base materials with a surface treatment agent such as a silane coupling agent, a titanium coupling agent, or methylolmelamine. Impregnation of the resin liquid () into the fibrous base material () can be carried out according to a conventionally known method. For example, a method of coating and impregnating a fibrous base material () with a resin liquid () using a flow coater method, a spray method, a roll coater method, etc.
Alternatively, it may be impregnated by passing through the liquid while dipping it. The fibrous base material () impregnated with the resin liquid () obtained as described above can be prepared by a conventionally known method (for example, a heat drying method, a vacuum drying method, an air drying method, or an appropriate combination of these methods). etc.) to remove the solvent (C) and lead to prepreg. At this time, if necessary, heat the copolymer (A) and epoxy resin (B) to a moderate temperature (for example, at a temperature of 150°C or less) during or after the removal of the solvent (C) to pre-react the copolymer (A) and the epoxy resin (B) to increase the hardness of the prepreg. The flow characteristics can be adjusted. The prepreg thus obtained is prepared in one or more sheets according to a conventionally known method, and if necessary, together with metal foil such as copper foil or aluminum foil under heat and pressure (e.g., 155-165°C, 20-20°C). 100Kg/cm ² ) for 120 minutes, and then introduced into a laminate. The laminate obtained by the method of the present invention has a low water absorption rate and a high insulation resistance, especially after boiling treatment. In addition, it has high heat resistance or soldering heat resistance after forced moisture absorption with a pressurizer.
It has excellent properties as a laminate. Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples. In addition, in the examples, the term "parts" basically means "parts by weight." Experimental example 1 75 parts of styrene in a flask, 25 parts of methacrylic acid,
100 parts toluene and benzoyl peroxide
0.5 part was added and reacted in a 90°C water bath with stirring under nitrogen atmosphere for 5 hours. Next, add the reaction solution
The precipitate formed by adding it to 4000 parts of methanol was separated, washed with water, and dried to obtain a styrene-methacrylic acid copolymer with an acid value of 143 (hereinafter referred to as copolymer (1)).
I got it. Experimental Example 2 Paramethylstyrene with an acid value of 89 was prepared in the same manner as in Experimental Example 1, except that 85 parts of paramethylstyrene was used in place of 75 parts of styrene, and 15 parts of acrylic acid was used in place of 25 parts of methacrylic acid. - An acrylic acid copolymer (hereinafter referred to as copolymer (2)) was obtained. Experimental Example 3 A sample with an acid value of 237 was prepared in the same manner as in Experimental Example 1, except that 50 parts of styrene was used instead of 75 parts of styrene, and 12 parts of methyl methacrylate and 38 parts of methacrylic acid were used instead of 25 parts of methacrylic acid. A styrene/methyl methacrylate/methacrylic acid copolymer (hereinafter referred to as copolymer (3)) was obtained. Example 1 Copolymer (1) 100 parts Epibis type epoxy resin 50 parts (manufactured by Ciba Geigy, GY-250, epoxy equivalent = 185) 0.1 part of benzyldimethylamine 75 parts of toluene were mixed and stirred to prepare varnish for laminate (1). ) was obtained. This varnish for laminates (1) is coated with glass cloth (Asahi Schuebel Co., Ltd.)
impregnated with (Style 216−AS450) and immediately 140
C. for 6 minutes to obtain a prepreg (1) with a resin content of 35% by weight. Layer 8 sheets of this prepreg (1), apply copper foil [manufactured by Furuka Circuit Oil Co., Ltd., TTAI (thickness 35 μm)] on the top and bottom,
Placed in a mold, temperature 165℃, pressure 40Kg/cm ² , time 120
Heating and pressing was performed under conditions of 1.6 mm to obtain a double-sided copper-clad laminate (1) with a thickness of 1.6 mm. As shown in Table 1, this product was superior in water absorption, insulation resistance, and heat resistance to a commercially available glass cloth-based epoxy resin laminate. Example 2 Copolymer (2) 100 parts Novolac type epoxy resin 50 parts (manufactured by Ciba Geigy, ECN-1299, epoxy equivalent = 235) Methyethylimidazole 0.2 parts Methyl ethyl ketone 30 parts Toluene 50 parts were mixed and stirred to form a laminate. A varnish (2) was obtained. Using this laminate varnish (2) and following the same procedure and method as in Example 1, a double-sided copper-clad laminate (2) having a thickness of 1.6 mm was obtained. The properties of this laminate are shown in Table 1,
In addition to water absorption, insulation resistance, and heat resistance, it was also excellent in soldering heat resistance after the pressure vacuum test (hereinafter abbreviated as PCT). Example 3 Copolymer (3) 100 parts Epibis type epoxy resin 130 parts (manufactured by Ciba Geigy, GY-6071, epoxy equivalent = 375) Benzyldimethylamine 0.1 parts Toluene 60 parts Methyl ethyl ketone 80 parts were mixed and stirred to prepare for laminated board. Obtained varnish (3). This varnish for laminates (3) is coated with glass cloth (Asahi Schuebel Co., Ltd.)
impregnated with (Style 216−AS450) and immediately 140
C. for 6 minutes to obtain a prepreg (3) with a resin content of 35% by weight. Similarly, this laminate varnish (3) was impregnated with glass nonwoven fabric (EP4075N manufactured by Nippon Vilene Co., Ltd.), dried at 130°C for 15 minutes, and the resin content was 68%.
A prepreg (4) of % by weight was obtained. Next, one prepreg (3) was stacked on the same copper foil as that used in Example 1, and then the prepreg (4)
Three sheets of prepreg (3) were further stacked, and finally the same copper foil as above was stacked. This laminate was sandwiched between molds at a temperature of 155℃, a pressure of 30Kg/cm ² , and a time of 120 minutes.
Heating and pressing was performed under conditions of 1.6 mm to obtain a composite-type double-sided copper-clad laminate (3) with a thickness of 1.6 mm. The properties of this double-sided copper-clad laminate (3) are shown in Table 1, and it was found to be superior to commercially available glass-based composite epoxy resin laminates in terms of water absorption and insulation. Example 4 Copolymer (1) 100 parts Brominated Epibis type epoxy resin 90 parts (manufactured by Dainippon Ink & Chemicals Co., Ltd., Epiclone)
145, epoxy equivalent = 365) 0.1 part of benzyldimethylamine and 100 parts of toluene were mixed and stirred, and using a varnish for laminates, a prepreg (5) with a resin content of 40% by weight was obtained by the same procedure and method as in Example 1. Ta. Using these eight sheets of prepreg, a flame-retardant double-sided copper-clad laminate (4) having a thickness of 1.6 mm was obtained in the same manner as in Example 1. Like the laminate produced in Example 1, this product exhibited excellent water absorption and insulation resistance as shown in Table 1. Example 5 Copolymer (1) 100 parts Brominated Epibis type epoxy resin 90 parts (manufactured by Dainippon Ink & Chemicals Co., Ltd., Epiclone)
145, epoxy equivalent = 365) 0.1 part of benzylmethylamine, 1 part of dicyandiamide, 1 part of antimony trioxide, 4 parts of toluene, 50 parts, and 100 parts of dioxane were mixed and stirred to obtain a laminate varnish (5). Add methylolmelamine resin to this laminate varnish (5) in advance.
Dry kraft paper (manufactured by Sanyo Kokusaku Pulp Co., Ltd., HL-10) impregnated with 12% by weight was impregnated and immediately dried at 155°C for 4 minutes to obtain a prepreg (6) with a resin content of 38% by weight. . Eight sheets of this prepreg (6) are stacked together, copper foil coated with epoxy resin adhesive is applied to both sides of the laminate, and then placed between molds at a temperature of 155
℃, pressure 90Kg/cm for ² hours and 120 minutes to produce a 1.6mm thick flame-retardant double-sided copper-clad laminate (5)
I got it. The properties of this product were superior in terms of water absorption, insulation, and heat resistance compared to general commercially available paper-based epoxy resin laminates. 【table】

Claims (1)

[Claims] 1 Aromatic vinyl compound (a) and unsaturated carboxylic acid (b)
A copolymer (A) with an acid value of 80 to 250 obtained as essential components and an epoxy resin (B) are mixed with a solvent (C) in a ratio such that the number of epoxy groups is 0.6 to 2.0 per carboxyl group. Production of a laminate, characterized in that a prepreg obtained by impregnating a fibrous base material () with a resin liquid () obtained by dissolving the solvent (C) and then curing the prepreg obtained by removing the solvent (C) under heat and pressure Method.