JPS6136846B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new and useful thermosetting resin composition, and more particularly to a thermosetting resin composition containing an epoxy resin and a new specific carboxylic acid anhydride as essential components. The object of the present invention is to provide excellent flexibility, strong crack resistance, quick curing properties, and good compatibility by combining the above-mentioned new specific carboxylic acid anhydride with an epoxy resin. It is an object of the present invention to provide a thermosetting resin composition having the following properties. Epoxy resins can be cured using amines or carboxylic acid anhydrides as curing agents, and such thermosetting resin compositions can be used in casting resins, molding materials, paints, adhesives, laminates, etc. It is well known that Various amine-based curing agents have traditionally been widely used as epoxy resin curing agents, but since amine-based compounds are relatively toxic, less toxic carboxylic acid anhydrides have recently been used instead. There is a growing tendency to do so. However, there are fewer types of carboxylic acid anhydrides used as epoxy resin curing agents than amine compounds. In particular, there are no acid anhydrides that impart good flexibility, crack resistance, etc. to cured resin products, and also have excellent workability. Conventionally, dodecenylsuccinic anhydride, polyazelaic acid polyanhydride, polysebacic acid polyanhydride, and the like are known as carboxylic acid anhydrides that impart flexibility, crack resistance, and the like. Dodecenyl succinic anhydride is a liquid and has good compatibility with other general carboxylic acid anhydrides and epoxy resins, but its cured resin has significantly poor crack resistance and lacks strong mechanical properties. Polyazelaic acid polyanhydride and polysebacic acid polyanhydride impart relatively good flexibility and crack resistance to cured resin products, but they differ from other general carboxylic acid anhydrides and epoxy resins. If the temperature is not raised above the respective melting points, the dissolution compatibility will be extremely poor, and the handling of the resin composition will be extremely inconvenient. Furthermore, since the starting materials for these polycarboxylic acid polyanhydrides are produced from limited natural fatty acids, there are restrictions in terms of production. As mentioned above, these carboxylic acid anhydrides have many practical difficulties. In view of the current situation, the present inventors have proposed that by combining a new specific carboxylic acid anhydride and an epoxy resin, a thermosetting resin composition having features that were previously unachievable can be obtained. This discovery led to the completion of the present invention. The carboxylic acid anhydride used in the present invention has the general formula ()
It has a repeating unit, and is represented by the general formula (), for example. It is obtained by subjecting a partial ester dicarboxylic acid to anhydration reaction. In the formula, R ₁ = residue of aliphatic, alicyclic or aromatic dicarboxylic acid. R ₂ = residue of aliphatic, cycloaliphatic or aromatic diol. n = 1-100. In the formula, R ₁ = residue of aliphatic, alicyclic or aromatic dicarboxylic acid. R ₂ = aliphatic, alicyclic or aromatic diol residue. The bonding form of the extending unit of the general formula () may be either one in which both ends of the general formula () are bonded in a linear chain or in a ring. Moreover, there is no problem even if it is a mixture of both. The partial ester dicarboxylic acid represented by the general formula () is a highly diverse compound obtained by appropriately combining R ₁ and R ₂ in the formula, and has improved flexibility, crack resistance, etc. It is used as a modifier that is added in small amounts to epoxy resin curing agents such as general carboxylic acid anhydrides, but since this partial ester dicarboxylic acid does not have a carboxylic anhydride group It cannot be used alone as an epoxy resin curing agent, and is only used in small amounts as a modifier for resin compositions, and when added in excess as a modifier, it can significantly reduce the curability of the resin composition. Furthermore, it causes deterioration of the electrical properties, mechanical strength, chemical resistance, and water resistance of the cured resin product. The present inventors converted the partial ester dicarboxylic acid, which had been used only as a modifier, into a partial ester carboxylic acid anhydride through an anhydration reaction, and by combining this carboxylic acid anhydride and an epoxy resin, It has been discovered that a resin composition can be obtained which has properties that are significantly superior to those obtained by partial ester dicarboxylic acid modification as described above.
That is, a thermosetting resin composition can be obtained that has excellent flexibility, wide flexibility, strong crack resistance, quick curability, good compatibility, and the like. R ₁ of the carboxylic acid anhydride having a repeating unit of the general formula () is a residue of an aliphatic, alicyclic or aromatic dicarboxylic acid, examples of which include succinic acid, maleic acid, dodecenylsuccinic acid, and glutaric acid. , hexahydrophthalic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, methyltetrahydrophthalic acid, endomethyleneterahydrophthalic acid, menathylendomethylenetetrahydrophthalic acid, phthalic acid, hexachloroendomethylenetetrahydrophthalic acid, tetrachlorophthalic acid ，
These are residues of tetrabromophthalic acid, etc., and one or more of these can be used. R ₂ of the carboxylic acid anhydride having a repeating unit of the general formula () is a residue of an aliphatic, alicyclic or aromatic diol, examples of which include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, Polybutylene glycol, 1,4-butanediol, 1,5-
pentanediol, neopentyl glycol,
1,6-hexanediol, dimethylolcyclohexane, 1,4-dihydroxycyclohexane, hydrogenated bisphenol A, hydroquinone,
These are residues of resorcinol, bisphenol A, bisphenol F, tetrabromobisphenol A, etc., and one or more of these can be used. The average molecular weight of the carboxylic acid anhydride having a repeating unit of the general formula () used in the present invention is:
Although not particularly limited, it is preferably 360 to 10,000, more preferably 350 to 3,500. If the molecular weight of the carboxylic acid anhydride is too small, it will be difficult to impart flexibility and crack resistance to the cured resin.
If the molecular weight of the carboxylic acid anhydride is 10,000 or more, the softening point of the carboxylic acid anhydride will be high, resulting in poor compatibility with the epoxy resin, which will not only make handling difficult, but also cause the cured resin to deteriorate. It is not possible to maintain various properties such as mechanical properties. The epoxy resin used in the present invention is not particularly limited, but examples thereof include bis(4-hydroxyphenyl)propane, 4,4'-dioxydiphenylmethane, resorgin, hydroquinone, catechol, 2,2- bis(4-hydroxy-2,
Di- or polyglycidyl ethers of diphenols or polyphenols such as 6-dibromphenyl) propane or condensates of formaldehyde and phenol (novolak): 1,4
-butanediol, neopentyl glycol, dipropylene glycol, diethylene glycol,
Glycerin, trimethylolpropane, pentaerythritol, 2,2-bis(4-hydroxy)
Di- or polyglycidyl ethers of glycols or polyols such as (cyclohexyl)propane: phthalic acid, terephthalic acid, isophthalic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride,
Polyglycidyl esters of polycarboxylic acids such as methyltetrahydrophthalic anhydride and trimethic acid; Triglycidyl esters of cyanuric acid and isocyanuric acid; Diglycidylhydantoins such as diglycidyl-dimethylhydantoin; diglycidyl-n-butylamine, diglycidyl- Phenylamine, 4,4'-bis(diglycidylamino)
- Di- or polyglycidiamines such as diphenylmethane: epoxidized polybutadiene, vinylcyclohexene dioxide, dicyclopentadiene dioxide, 1-(1-methyl-1,
2-Epoxyethyl)-3,4-epoxymethyl cyclohexane, 3,4-epoxy cyclohexylmethyl-3,4-epoxy cyclohexane carboxylate, bis(3,4-epoxy cyclohexylmethyl) phthalate, dipentene oxide, diethylene glycol-bis(3,4-epoxy-cyclohexene carboxylate), 3,4-epoxy-hexahydrobenzal-3,4-epoxy-cyclohexane-
1,1-dimethanol, ethylene glycol-bis(3,4-epoxytetrahydro-dicyclopentadien-8-yl)ether, or 2,7
- epoxidized polyunsaturated compounds such as epoxidates of diesters made from octadienol or 1,7-octadienol and dibasic acids such as phthalic anhydride or hexahydrophthalic anhydride; It is a diglycidyl ether obtained by hydrogenating the aromatic ring of the diglycidyl ether of 4-hydroxyphenyl)propane or bis(2-hydroxyphenyl)methane to an aliphatic ring, or bis(4-hydroxyphenyl)propane. phenyl) propane or bis(2-
Diglycidyl ether obtained by reacting an alcoholic dihydroxy compound produced by the addition reaction of (hydroxyphenyl)methane with ethylene oxide or propylene oxide and epichlorohydrin in the presence of an acid catalyst such as BF ₃ , followed by dehydrochlorination and ring closure. can be mentioned. In the present invention, in order to obtain particularly excellent flexibility and wide range of softness, bis(4-hydroxyphenyl)propane or bis(4-hydroxyphenyl)methane and propylene oxide are combined. Particularly preferred is a diglycidyl ether type epoxy resin of an alcoholic dihydroxy compound produced by an addition reaction. In addition, in order to obtain strong crack resistance, the epoxy equivalent of the above epoxy resin should be 220~220.
It is particularly preferable to use a glycidyl ether type epoxy resin of bis(4-hydroxyphenyl)propane, which is 500, in combination. The present invention relates to the epoxy resin and the general formula ()
It is obtained by mixing as an essential component a carboxylic acid anhydride having a repeating unit of 30 parts by weight of the carboxylic acid anhydride
~200 parts by weight. If the amount of the carboxylic acid anhydride is less than 10 parts by weight relative to 100 parts by weight of the epoxy resin, the characteristics of the carboxylic acid anhydride cannot be exhibited. Further, if the carboxylic acid anhydride exceeds 300 parts by weight per 100 parts by weight of the epoxy resin, it becomes excessive as a curing agent component, and the properties of the cured resin product, including electrical properties and water resistance, deteriorate overall. The resin composition of the present invention can be used as an epoxy resin curing agent such as other carboxylic anhydrides, such as succinic anhydride,
Maleic anhydride, copolymer of maleic anhydride and vinyl compound, dodecenyl succinic anhydride, glutaric anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylene Can be used in combination with tetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, phthalic anhydride, hexachloroendomethylenetetrahydrophthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. I can do it. The resin composition of the present invention further includes a reactive diluent,
In particular, monoepoxide compounds such as butyl glycidyl ether, phenyl glycidyl ether, para-sec-butylphenyl glycidyl ether, cresyl glycidyl ether can be included. Also, plasticizers such as dibutyl phthalate, dioctyl phthalate, tricresyl phosphate,
Non-reactive diluents can be included. Furthermore, the resin composition of the present invention may contain other additives, such as quartz powder, mica, glass fiber, cellulose, talc, clay, kaolin, bentonite, calcium carbonate, hydrated alumina, or metal powder, as necessary. Fillers such as aluminum powder; dyes, pigments; molding lubricants; flame retardants and other modifiers can be added. The resin composition of the present invention can be cured as it is, but in order to sufficiently proceed with curing, it is more preferable to use it in combination with the following accelerators, such as triethylamine, N,N-dimethylbenzylamine, , triethanolamine, N,N-dimethylcyclohexylamine, tris(dimethylaminomethyl)phenol, diazabicycloundecene: Amine salts such as BF ₃ -monoethylamine: 2-ethyl-4-methylimidazole Imidazoles such as: or metal alcoholates such as sodium alcoholate are common. The resin composition of the present invention can be prepared by mixing an epoxy resin, the carboxylic anhydride, and, if necessary, an epoxy resin curing agent such as another carboxylic anhydride and other components using a stirrer, a kneader, a heating roll, an ink roll, etc. This resin composition can be used in various forms such as sheet, granule, powder, and liquid. The thus obtained thermosetting resin composition of the present invention has various features. In other words, it not only has excellent flexibility, strong and wide flexibility, strong clutch resistance, rapid hardening, and good compatibility, but also has excellent electrical properties, mechanical properties, heat resistance, and difficulty. It has characteristics such as flammability, chemical resistance, water resistance, moisture resistance, weather resistance, etc., and the ability to obtain a light-colored and transparent cured resin product. The reason why the resin composition of the present invention has such various features is that the molecular structure of the carboxylic acid anhydride is rich in diversity. This diversity is due to the fact that the molecular structure, molecular chain length, molecular polarity, etc. of the partial ester dicarboxylic acid, which is the unit of the carboxylic acid anhydride, can be adjusted over a wide range, and the carboxylic acid anhydride can be obtained by combining these various units. It comes from being able to do something. Next, the present invention will be specifically explained using examples.
Hereinafter, parts and percentages are based on weight unless otherwise specified. The carboxylic acid anhydride having a repeating unit represented by the general formula () used in the examples of the present invention and the partial ester dicarboxylic acid used in the comparative examples were synthesized by the following method. Attach a stirrer, thermometer, and nitrogen gas introduction tube to the four-necked flask containing contents 1, and add diol 1.
mol and 2 mol of dicarboxylic acid were charged and reacted at 160° C. for 3 hours in a nitrogen gas atmosphere to obtain a partial ester dicarboxylic acid. The partially ester dicarboxylic acids obtained are shown in Table 1. Next, excess acetic anhydride was added to the above partial ester dicarboxylic acid, and the mixture was reacted at 160° C. for 1 hour under reduced pressure. During the reaction, the reaction was completed while removing excess acetic anhydride and by-produced acetic acid from the system to obtain a carboxylic acid anhydride. The obtained carboxylic acid anhydrides are shown in Table 1.

[Table] Examples 1 to 3, Comparative Examples 1 to 5 The partial ester dicarboxylic acids obtained in Synthesis Example 1 and Synthesis Example 3 and the carboxylic acid anhydride of the general formula () were mixed with other components, and the Resin compositions of Examples 1 to 3 and Comparative Examples 1 to 5 were prepared. Second
The table shows the blending ratio. Table 3 shows the characteristics of each example and each comparative example. As shown in Table 3, the resin composition of the present invention has excellent compatibility, curability, crack resistance, and flexibility, as well as excellent electrical properties, water resistance, and heat resistance compared to the comparative example. It is clear that they have both.

【table】

【table】

【table】

[Table] Example 4 and Comparative Example 6 Example 4 and Comparative Example A resin composition of No. 6 was prepared. Table 4 shows the blending ratio. Table 5 shows the characteristics of Examples and Comparative Examples. As shown in Table 5, the resin composition of the present invention has extremely fast curing compared to the comparative example, has strong crack resistance, and also has extremely excellent mechanical properties and good electrical properties. is clear.

【table】

【table】

[Table] As explained above, the resin composition of the present invention can be used as an impregnating resin for electrical parts such as coils, capacitors, and motors, a casting resin for encapsulating dry transformers, semiconductor parts, etc., as well as molding materials, paints, and adhesives. It has a wide variety of applications, such as adhesives and laminates, and is extremely useful industrially.

Claims (1)

[Scope of Claims] 1. A thermosetting resin composition comprising an epoxy resin and a carboxylic acid anhydride having a repeating unit represented by the general formula () as essential components. In the formula, R ₁ = residue of aliphatic, alicyclic or aromatic dicarboxylic acid. R ₅ = residue of aliphatic, cycloaliphatic or aromatic diol. n = 1-100. 2 In the general formula (), R ₁ is a residue of one or more dicarboxylic acids selected from tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, and methylhexahydrophthalic acid. The thermosetting resin composition according to claim 1, characterized in that: 3 In the general formula (), R ₂ is 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol,
3. The thermosetting resin composition according to claim 1 or 2, which is a residue of one or more diols selected from polypropylene glycol. 4. Claim No. 4 characterized in that the mixing ratio of the epoxy resin and the carboxylic acid anhydride having a repeating unit represented by the general formula () is 100 parts by weight of the epoxy resin and 10 to 300 parts by weight of the carboxylic acid anhydride. 1
The thermosetting resin composition according to item 1, 2 or 3. 5 Claims 1 and 2, characterized in that the average molecular weight of the carboxylic acid anhydride having a repeating unit represented by the general formula () is 350 to 10,000.
Thermosetting resin composition according to item 3 or 4.