JPS6231723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curable resin composition that can be cured by heating or irradiation with ultraviolet rays, electron beams, etc., and can provide a cured product with excellent heat resistance.

BACKGROUND ART In recent years, in various industrial fields, particularly in the field of electrical equipment, insulating materials used have come to be required to have a high degree of heat resistance in order to reduce the size and weight of equipment and improve reliability. Regarding impregnating varnishes, conventional styrene-based solvent-free varnishes tend to volatize styrene during heat curing, which poses two problems in terms of economy and working environment. Therefore,
Measures are being taken such as replacing styrene with monomers that have lower odor and toxicity, or curing the surface with ultraviolet rays, etc., and then completely curing the interior by heating. An object of the present invention is to provide a curable resin composition with good heat resistance that can meet such industrial demands.

That is, the present invention is based on the general formula (However, in the formula, R ₁ is hydrogen or a methyl group, R ₂ is a glycol residue or the general formula (-R'-COO-R''-COO)-
A linear polyester oligomer residue represented by _n R'- (wherein R' is a glycol residue, R'' is a dibasic acid residue, and m is an integer from 1 to 20), _R3 is a diisocyanate residue , n is an integer of 1 to 10), 5 to 50 parts by weight of a compound having one or more polymerizable unsaturated groups in the molecule, and a radical polymerization initiator and/or Or photosensitizer 0
-10 parts by weight of the curable resin composition.

The curable resin composition of the present invention can be cured by any one of the following three methods or a combination of these methods. One method is the generally widely used method of adding a radical polymerization initiator and curing by heating. As the radical polymerization initiator, common ones such as benzoyl peroxide, methyl ethyl ketone peroxide, tertiary butyl perbenzoate, dicumyl peroxide, and azobisisobutyronitrile can be used, and these are represented by the general formula (1). Compounds and compounds having one or more polymerizable unsaturated groups in the molecule
Approximately add 0.1 to 5 parts by weight per 100 parts by weight.
It may be heated at a temperature of 80 to 180°C for about 2 to 10 hours. Another method is to add a photosensitizer to
This is a method of curing with ultraviolet light emitted from various mercury lamps, xenon lamps, etc. Examples of photosensitizers include benzoin and alkyl ethers of benzoin such as benzoin ethyl ether, alkyl ethers of benzophenone such as benzophenone and isetophenone, polynuclear quinones such as anthraquinone and 2-ethylanthraquinone, and polysulfides such as diphenyl disulfide. , azo compounds such as azobisisobutyronitrile, decyl chloride, Michler's ketones, etc.
These are added in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the compound represented by the general formula (1) and the compound having one or more unsaturated groups in the molecule. Yet another method is to cure the material by irradiating it with ionizing radiation such as electron beams, X-rays, and gamma rays. From the viewpoint of safety and operability, it is preferable to use an electron beam. When curing with an electron beam, there is no need to add a radical weight initiator or photosensitizer.

The compound represented by the general formula (1) used in the present invention can be synthesized as follows. first,
First, trimellitic anhydride (hereinafter abbreviated as TMA) and a diisocyanate compound are reacted in a mixing ratio such that the diisocyanate compound is in excess to obtain a compound represented by the following general formula (i). As the diisocyanate compound, for example, tolylene diisocyanate, diphenylmethane diisocyanate, diphenyl ether diisocyanate, xylylene diisocyanate, etc. are used.

(However, R ₃ and n in the formula are the same as above) Glycols represented by the following general formula HO―R ₂ -OH ... (ii) (However, R ₂ in the formula is the same as above), such as ethylene glycol, diethylene glycol, One or more of triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,6-hexanediol, neopentyl glycol, or the following general formula HO (-R'-COOR'') - _n COO- R′-OH ...(iii) (wherein R′, R″, m are the same as above) A linear polyester oligomer having a hydroxyl group at the end obtained by reacting a dibasic acid represented by the formula with glycol. After the reaction, the following general formula (However, R ₁ in the formula is the same as above.) A compound represented by, for example, acrylic acid, methacrylic acid, or a chloride or lower alkyl ester of these acids is reacted. The linear polyester oligomer of formula (iii) can be obtained by polycondensing a dibasic acid and a glycol at a blending ratio in which the glycol is in excess by a conventional method. Usable dibasic acids include phthalic acid, isophthalic acid, terephthalic acid, maleic acid, adipic acid, succinic acid, fumaric acid, anhydrides and lower alkyl esters of these acids, and glycols include the above-mentioned formulas. Examples include compounds represented by (ii). In formula (iii), the value of m is preferably 1 to 20, and in formula (i), the value of n is preferably 1 to 10. When m exceeds 20 or when n exceeds 10, the viscosity of the resulting resin composition increases and workability decreases.

Examples of compounds having one or more polymerizable unsaturated groups in the molecule include vinyl compounds, divinyl compounds, and unsaturated polyester resins. Examples of vinyl compounds include acrylic acid, methacrylic acid, lower alkyl esters of these acids, glycidyl acrylate, styrene, and vinyltoluene. Examples of divinyl compounds include ethylene glycol di(meth)acrylate (diacrylate or dimethacrylate, the same applies hereinafter), diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, etc. ) Glycol esters of acrylic acid, bis(meth)acryloxyalkyl terephthalate, bis(meth)acryloxyalkyl isophthalate,
Examples include reaction products of (meth)acrylic acid and polyester polyols such as bis(meth)acryloxyphthalate and bis(meth)acryloxyalkylhexahydrophthalate, divinylbenzene, diallyl phthalate, and diallyl isophthalate. As the unsaturated polyester resin, a usual one obtained by polycondensing an unsaturated dibasic acid, a glycol, and, if necessary, a saturated dibasic acid can be used. These compounds having one or more polymerizable unsaturated groups in the molecule may be used alone or in combination.
In addition, the amount used is 95 to 50% of the compound represented by formula (i).
The amount is 5 to 50 parts by weight, and the amount is 5 to 50 parts by weight.
If the amount is less than 50 parts by weight, the effect of improving workability by reducing the viscosity of the resin composition, and the effect of improving flexibility and adhesion will be poor, and if it exceeds 50 parts by weight, the heat resistance of the cured product obtained will decrease.

The resin composition of the present invention can be used for surface protection paints, films, sheets, etc., and can also be widely and generally used as materials for casting, molding, and impregnation.

EXAMPLES The present invention will be explained in more detail below with reference to Examples.

Example A 418.6 g of diphenylmethane diisocyanate,
Trimellitic anhydride 160.7g, N-methyl-2-
Put 869 g of pyrrolidone into a four-necked flask equipped with a stirrer, thermometer, fractionator tube, and nitrogen introduction tube.
After reacting at 100°C for 2 hours, it was further reacted at 140°C for 3 hours. When a small amount of the product was sampled and infrared absorption spectrum analysis of the precipitate obtained by pouring it into methanol, imide ring absorption was observed at 1780 cm ^-1 , and amide bonds were observed at 1660 cm ^-1 and 1540 cm ^-1 . absorption was observed. dipropylene glycol with
Add 117.8g and 93.2g of diethylene glycol to 150
The reaction was carried out at ℃ for about 4 hours. Thereafter, the temperature was raised to 120°C, 180 g of methacrylic acid was added, and the reaction water was distilled out of the system. After distilling off 85% of the theoretical amount of water,
N-methyl-2-pyrrolidone and excess methacrylic acid were distilled off under reduced pressure to obtain an unsaturated compound of the type represented by general formula (1).

Example 1 95 parts by weight of the unsaturated compound obtained in Example A and 5 parts by weight of glycidyl methacrylate were stirred and mixed, 1% by weight of benzoyl peroxide was added to this mixture, and the mixture was applied to a 0.25 mm thick steel plate. It was coated to a thickness of about 40 microns and heated at 100°C for 1 hour and then at 120°C for 2 hours. The cured coating film thus obtained had a pencil hardness of 5H and passed the 50 mmφ mandrel test. After heating this coating film at 200℃ for 24 hours, we measured the pencil hardness again, and found that it maintained the same 5H value as before heating and deterioration, and also in the mandrel test.
It passed the 50mmφ test, showing that it has excellent heat resistance.

Example 2 70 parts by weight of the unsaturated compound obtained in Example A, 25 parts by weight of diacrylic ester of bishydroxyethyl isophthalate, and 5 parts by weight of glycidyl methacrylate were mixed with stirring. 1.5% by weight of benzoin ethyl ether was added to this mixture and applied to a 0.25mm thick steel plate to a thickness of approximately 40 microns. -3000) Light was irradiated for 2 minutes at a distance of 20 cm below. The cured coating film thus obtained had a pencil hardness of 4H and passed a 30 mmφ mandrel test. This coating film was heated to 200℃ for 24 hours.
The pencil hardness is 4H and 30mm after being heated and deteriorated for a long time.
Passed the φ mandrel test.

Example 3 80 parts by weight of the unsaturated compound obtained in Example A, 10 parts by weight of dimethacrylic ester of bishydroxyethyl isophthalate, and 10 parts by weight of diethylene glycol diacrylate were mixed with stirring. A cleaner armature made of polyester copper wire was impregnated with 2% by weight of benzoin ethyl ether and 1% by weight of benzoyl peroxide based on the mixture. 3000) Bottom 20cm
The surface layer was cured by irradiation with light for 3 minutes at a distance of , and then heated in a heating oven at 130° C. for 4 hours to fully cure the inside. The cleaner armature thus obtained was placed in a dryer at 150°C, left for 168 hours, and then taken out and checked for insulation performance such as rotational impulse and withstand voltage, but no abnormality was found.

According to the curable resin composition of the present invention, by using ultraviolet rays or electron beams, the curing speed is faster than when only heat is used as a curing means, so energy usage efficiency and productivity are improved. . Furthermore, when ultraviolet rays and heat are used in combination, the surface layer is cured by the ultraviolet rays, so the monomer does not volatilize even if heat is subsequently applied, which is preferable in terms of economy and work environment.

Claims (1)

[Claims] 1. General formula (However, in the formula, R ₁ is hydrogen or a methyl group, R ₂ is a glycol residue or the general formula (-R′-COO-R″-COO
) _—n R′—(wherein R′ is a glycol residue, R″ is a dibasic acid residue, m is an integer from 1 to 20), a linear polyester oligomer residue, R ₃ is a diisocyanate 95 to 50 parts by weight of an unsaturated compound represented by a residue (n is an integer from 1 to 10), 1 in the molecule
1. A curable resin composition comprising 5 to 50 parts by weight of a compound having at least 10 polymerizable unsaturated groups and 0 to 10 parts by weight of a radical polymerization initiator and/or a photosensitizer.