JPS6228168B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a flame-retardant resin composition for laminates that has excellent heat resistance such as heat discoloration, whitening due to interlayer peeling due to thermal shock (hereinafter referred to as Measling), and glass transition point (hereinafter referred to as Tg). . Conventionally, in the process of forming circuits and mounting components on laminates or copper-clad laminates, there has been a demand for flame-retardant resins that exhibit little discoloration, have a high Tg due to board characteristics, have little measling, and from the standpoint of product image and aesthetics. In epoxy resins, curing agents include acid anhydrides such as hexahydrophthalic anhydride, 4-methyl or 4-ethylhexahydrophthalic anhydride, nitrogen compounds such as dicyandiamide, 3.3'dichloro4.4'diaminodiphenylmethane, and phenol formaldehyde resins. Used industrially.
However, when an acid anhydride is used as a curing agent, heat resistance is good, but there is a drawback that moisture resistance at the B stage is poor. Nitrogen compounds such as dicyandiamide have good storage stability, curing properties, etc., but have the disadvantage that the laminated plate discolors when heated due to oxidation of the nitrogen atoms contained therein. In addition, phenol formaldehyde resin also had high Tg and good measling properties, but discoloration by heating was not good. The inventors of the present invention have conducted extensive studies on the discoloration of laminates that occurs when this phenol formaldehyde resin is used as a curing agent for epoxy resins, and have found that the main cause of this discoloration is the oxidation of the methylene bond at the P position in the phenol resin. Based on this idea, it is possible to obtain heat resistance by using a resin with relatively few P-position methylene bonds in phenol formaldehyde resin, which causes discoloration on heating, that is, high orthophenol formaldehyde resin, and it is also relatively effective as a flame retardant imparting agent. It is inexpensive, has high halogen content, is reactive with epoxy groups, and has P of hydroxyl group.
It has been found that flame retardancy can be obtained by using halogenated bisphenol A that does not have a methylene bond at the position. As described above, an object of the present invention is to provide a flame-retardant resin composition for laminates that has excellent heat resistance. The epoxy compound used in the present invention is 1
There are no particular limitations as long as it is a so-called epoxy resin consisting of a compound having two or more epoxy groups in the molecule. Specific examples include bisphenol epoxy resins, novolak epoxy resins, polyphenol epoxy resins, polyglycol epoxy resins, and alicyclic epoxy resins. It is also possible to use two or more of these in combination. If the epoxy compound is a substance that is easily discolored by oxidation, the cured product will be slightly discolored by heating, but the degree of discoloration is significantly improved compared to when a normal phenol formaldehyde resin is used. The halogenated bisphenol A used in the present invention is

[Formula] R is hydrogen or halogen, and at least one R is a halogen compound, such as tetrabromobisphenol A and tetrachlorobisphenol A. The high-orthophenol formaldehyde resin used in the present invention refers to one with an ortho ratio of 50% or more, preferably 70% or more. The ortho rate was calculated using the following formula based on the infrared absorption spectrum. Ortho rate (%) = ^D 760cm ⁻¹ / ^D 820cm ⁻¹ ×1.44+ ^D 7
60 cm ⁻¹ ×100 High orthophenol Formaldehyde As the phenols used in the production of the resin, phenols or alkylphenols can be used, but in consideration of oxidative discoloration of alkyl groups, phenols with as few substituents as possible are preferred. Also
2.2 Bis(4'-oxyphenyl)propane [bisphenol A] has a reactive position only at the ortho position of formaldehyde and the phenolic hydroxyl group, so formaldehyde resins of bisphenol A are also included in high orthophenol resins. The formaldehyde source is not particularly limited, such as formalin and paraformaldehyde. The molar ratio of formaldehyde to phenols is not particularly limited, but if it is 1 or more, gelation may occur during resin synthesis. On the other hand, if the amount is too small, a large amount of unreacted phenol will remain and the yield of the resin will be poor. Unreacted phenol remaining at the end of the synthesis reaction must be removed by methods such as water flow, steam distillation, vacuum distillation, and atmospheric distillation. The amount thereof is preferably 3% by weight or less, more preferably 0.3% by weight or less in the borax resin. This unreacted phenol does not significantly affect the discoloration of the resin laminate, but it greatly affects the Tg and heat resistance of the resin laminate, such as Measling. Among the above methods for removing unreacted phenol, when a water stream is used, the synthesis catalyst is also removed at the same time as the phenol, so the electrical properties of the resin laminate tend to be significantly improved. As the resin synthesis catalyst, alkaline earth metal hydroxides, acetates, or other metal halides can be used, and the catalyst is not particularly limited. In the case of bisphenol A, since the reaction position with formaldehyde is only the ortho position, there is no particular limitation as long as it is a novolak synthesis catalyst. In order to prevent oxidative discoloration of the resin during synthesis, it is preferable to synthesize under a nitrogen stream, but there is no particular limitation. If necessary, amines such as benzyldimethylamine, imidazole and its derivatives,
It is also possible to use BF ₃ amine complexes and the like. It is also possible to use ordinary inorganic or organic fillers as fillers in the resin composition of the present invention. It is also possible to use antimony trioxide to improve flame retardancy. Epoxy compound, halogenated bisphenol A
The mixing ratio of halogenated bisphenol A and high-orthophenol formaldehyde resin is 0.7 to 2.0 equivalents, preferably 0.9 to 12 equivalents, and the halogen content is 10 to 25 equivalents of hydroxyl groups per equivalent of epoxy group.
Weight percent is preferred. Note that when antimony trioxide is used in combination, it is also possible to mix it under conditions where the halogen content is low. There are no particular restrictions on the method or order for mixing the two. Further, the method of impregnating the base material is not particularly limited, and a solvent may be used, or a method of impregnating the resin by thermally melting it without using a solvent is also possible. The present invention will be explained below based on examples. Example 1 940g of phenol, 250g of paraformaldehyde
g, 12 g of zinc acetate for 4 hours while passing nitrogen through it.
℃, then heated at 150℃ for 2 hours and concentrated under normal pressure. Further, in order to remove unreacted phenol, the product was washed with water and dehydrated under reduced pressure to obtain a high orthophenol novolak resin [A]. The unreacted phenol content of this resin was 0.2% and the ortho rate was 72%.
[A] A resin composition was prepared by blending resins as follows. [A] Resin 100 parts by weight Epoxy compound [Epicote 828 Yuka Epoxy Co., Ltd. trade name] 320 parts by weight Tetrabromo 2.2-bis(4-hydroxyphenyl)propane (Fire Guard 2000 Teijin Chemicals trade name) 210 parts by weight Benzyldimethylamine 3.2 parts by weight Methyl ethyl ketone 400 parts by weight This resin composition was impregnated into a glass cloth base material and heated to 150°C.
After drying for 25 minutes, an impregnated base material with 50% adhesion resin was created. Layer a predetermined number of these sheets and place copper foil on the surface.
A copper clad laminate was produced by heating and pressing at 170°C and 30 kg/cm ² for 90 minutes. Comparative example 1 940g of phenol, 250g of paraformaldehyde
10 g of oxalic acid was heated at 120°C for 4 hours while flowing nitrogen gas, then heated at 150°C for 2 hours and concentrated under normal pressure. Furthermore, in order to remove unreacted phenol, vacuum distillation was performed to obtain phenol novolak resin [B].The unreacted phenol content of this resin was 6%, and the ortho rate was
It was 46%. [B] A resin composition was prepared by blending resins as follows. [B] Resin 100 parts by weight Epicote 828 320 parts by weight Fireguard 2000 210 parts by weight Benzyldimethylamine 3.2 parts by weight Methyl ethyl ketone 400 parts by weight This resin composition was impregnated into a glass cloth base material and heated to 150°C.
The material was dried for 5 minutes to create an impregnated base material with a 50% amount of resin attached. A predetermined number of these sheets were stacked, a copper foil was placed on the surface, and the sheets were heated and pressed at 170° C. and 30 kg/cm ² for 90 minutes to produce a copper-clad laminate. Example 2 [A] A resin composition was prepared by blending resins as follows. [A] Resin 100 parts by weight Epoxy compound (Epicote 154 manufactured by Yuka Ciel Epoxy Co., Ltd., trade name) 320 parts by weight 2.2-bis(3bromo4hydroxy)propane
180 parts by weight BF ₃ /piperidine 6 parts by weight Methyl ethyl ketone 400 parts by weight A resin-impregnated base material was prepared from this resin composition in the same manner as in Example 1. A predetermined number of these sheets were stacked together, a copper foil was placed on the surface, and the sheets were heated and pressed to produce a copper-clad laminate. Comparative Example 2 [B] A resin composition was prepared by blending resins as follows. [B] Resin 100 parts by weight Epoxy compound (Epicote 154 manufactured by Yuka Ciel Epoxy Co., Ltd., trade name) 320 parts by weight 2.2 bis(3bromo4hydroxy)propane
180 parts by weight BF ₃ /piperidine 6 parts by weight Methyl ethyl ketone 400 parts by weight A resin-impregnated base material was prepared from this resin composition in the same manner as in Example 1. A predetermined number of these sheets were stacked together, a copper foil was placed on the surface, and the sheets were heated and pressed to produce a copper-clad laminate. Example 3 Bisphenol A 900g, 37% formalin 200
g and 9 g of oxalic acid were placed in a four-necked flask equipped with a condenser and a stirrer, heated under reflux for 2 hours to react, and then dehydrated and concentrated to obtain a bisphenol novolac resin [C]. Using this, a resin composition was prepared by blending as follows. [C] Resin 100 parts by weight Epicoat 828 320 parts by weight Fireguard 2000 210 parts by weight Benzyldimethylamine 3.2 parts by weight Methyl ethyl ketone 400 parts by weight This resin composition was used in the same manner as in Example 1 to prepare a resin-impregnated base material. A predetermined number of these sheets were stacked together, a copper foil was placed on the surface, and the sheets were heated and pressed to produce a copper-clad laminate. The properties of the copper-clad laminates of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in the table above.

[Table] By using the resin composition of the present invention, it has become possible to obtain a flame-retardant laminate having good thermal discoloration properties, measling properties, etc., and a high Tg.

Claims (1)

[Scope of Claims] 1. An epoxy compound having two or more epoxy groups in the molecule, halogenated bisphenol A,
The epoxy group of the epoxy compound is composed of a high-orthophenol formaldehyde resin whose main raw material is phenol or bisphenol A and whose ortho ratio of methylene bonds is at least 50%.
(a) and the hydroxyl group (b) of the halogenated bisphenol A and high-orthophenol formaldehyde resin in an equivalent ratio of a:b=1:0.7 to 2.0. Flame retardant resin composition for use. 2 The amount of unreacted phenols contained in the high orthophenol formaldehyde resin is 3% by weight.
A flame-retardant resin composition for a laminate according to claim 1, which is as follows. 3. The flame-retardant resin composition for a laminate according to claim 1, wherein the halogenated bisphenol A is tetrabromo 2.2-bis(4hydroxyphenyl)propane.