JPH06316611A - Thermosetting resin composition and its curing method - Google Patents

Abstract

PURPOSE:To provide the subject composition comprising a specific allyl ester, a specific curing agent and an unsaturated polyester resin in a specified ratio, not generating cracks, low in contraction rate, excellent in hardness, mechanical strength, water resistance and transparency, and useful for molded products such as plastic bathtubs, etc. CONSTITUTION:This composition comprises (A)2-60wt.% of an allyl ester oligomer having an unsaturation degree of 2-45 represented by an iodine value and a number-average mol.wt. of 1000-50000 converted into polystyrene and measured by GPC, (B) 40-98wt.% of an unsaturated polyester resin, and (C) a tertiary alkylperoxy 2-ethylhexanoate of the formula (R is methyl, ethyl, tert-butyl) such as tertiary amylperoxy 2-ethylhexanoate in an amount of 0.1-10 pts.wt. per 100 pts.wt. of the components A+B. The composition is preferably cured at 40-120 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition comprising an allyl ester oligomer and an unsaturated polyester resin, which has a low shrinkage ratio and a cured product is transparent, and a curing method thereof. In particular, the present invention is useful for the production of molded products having a transparent feeling, for example, artificial marble-like polybass or various resin molded products for which it is desired to prevent cracks caused by shrinkage.

[0002]

2. Description of the Related Art As a method for curing a single composition of an unsaturated polyester resin, various curing methods have been proposed in order to adapt it to the molding temperature and molding cycle. on the other hand,
Regarding the curing of compounds having an allyl group, it is known that diallyl phthalate and its polymer and diallyl carbonate are cured, but it is known that the reactivity is remarkably lowered due to degenerative chain transfer of the allyl group. ing. Therefore, in order to cure these compounds, the curing temperature is raised or the curing requires a long time. The allyl ester oligomer used in the present invention has an allyl group at the terminal, and its reactivity is expected to be remarkably reduced as compared with diallyl carbonate, but with regard to curing characteristics, sufficient knowledge is still available. Has not been obtained. Therefore, an effective curing method for the compounded composition of the allyl ester oligomer and the unsaturated polyester resin as in the present invention is not known.

[0003]

In recent years, there has been an increasing demand for resin molded products which are not colored like artificial marble and require transparency. Conventional unsaturated polyester resins are insufficient for such demands. And such an artificial marble-like resin molded product is molded at an intermediate temperature such as 60 to 100 ° C. in order to prevent generation of voids and cracks during molding. Therefore, a thermosetting resin composition containing an unsaturated polyester resin satisfying the above-mentioned various conditions and a curing method capable of efficiently molding at such an intermediate temperature are desired.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that a thermosetting resin obtained by adding a specific allyl ester oligomer and a specific peroxy ester to an unsaturated polyester resin. The present invention has completed the present invention by finding that it meets the above-mentioned demands and that the curing reaction can be efficiently proceeded, and that a molded product having no coloration and good transparency can be obtained. That is, in the present invention, the degree of unsaturation expressed by iodine value is 2 to 45, and the polystyrene reduced number average molecular weight measured by GPC is 1000 to
A compounding composition of 2 to 60% by weight of an allyl ester oligomer of 50,000 and an unsaturated polyester resin of 40 to 98% by weight, and the following general formula as a curing agent:

[Chemical 5] (In the formula, R represents a methyl group, an ethyl group, or a tertiary butyl group), a thermosetting resin composition comprising only a tertiary alkylperoxy 2-ethylhexanoate or further a dialkylperoxydicarbonate. The present invention relates to an article and a curing method thereof.

First, the curing agent will be described. In the tertiary alkylperoxy 2-ethylhexanoate used in the present invention, each R in the general formula (Formula 1) is a methyl group,
Compounds having an ethyl group and a tertiary butyl group, specifically, tertiary amylperoxy 2-ethylhexanoate, tertiary hexylperoxy 2-ethylhexanoate and tertiary octylperoxy 2-ethylhexano I am Ato. These tertiary alkyl peroxy 2-ethylhexanoates cure efficiently at intermediate temperatures such as 40 to 120 ° C., and, in addition, the compounded composition of the allyl ester oligomer and unsaturated polyester resin of the present invention is used. There is an advantage that it does not cause coloring. Tertiary alkylperoxy 2-ethylhexanoates are limited to the above compounds. For example, in the case of tertiary butyl peroxy 2-ethylhexanoate, there are problems in the coloring property and hardness of the cured product, as well as residual monomers in the cured product.

Further, these tertiary alkylperoxy 2
Specific examples of the dialkylperoxydicarbonate used in combination with -ethylhexanoate include diethylperoxydicarbonate, di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, diethoxyethylperoxydicarbonate and dibutoxy. Ethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate, di-secondary butyl peroxydicarbonate, di2-ethylhexyl peroxydicarbonate, di-n-dodecyl peroxydicarbonate, dicyclododecyl peroxydicarbonate, dicetyl peroxydicarbonate, dipara Tertiary butyl cyclohexyl peroxydicarbonate, dimyristyl peroxydicarbonate and the like,
Particularly preferred dialkyl peroxydicarbonates include dipara tert-butylcyclohexyl peroxydicarbonate and dimyristyl peroxydicarbonate. These are dialkyl peroxydicarbonates that are solid at normal handling temperatures, minus 1
It is convenient because there is no need to handle it under cooling at 5 ° C or lower. The amount of the curing agent used is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the allyl ester oligomer and the unsaturated polyester resin. It is necessary to add a larger amount than the curable acrylic resin. If it is too small, it will lead to poor curing, and if it is too large, it will cause cracks in the cured product, and coloring and foul odor due to the thermal decomposition product are not preferred. The combined use of a tertiary alkylperoxy 2-ethylhexanoate and a dialkylperoxydicarbonate is effective at a low curing temperature and when increasing the curing rate, and usually a tertiary alkylperoxy 2-ethylhexanoate is used. 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, is used per 1 part by weight.

The allyl ester oligomer used in the present invention has a degree of unsaturation expressed by an iodine value of 2 to 45 measured by Wijs method, and a polystyrene-equivalent number average molecular weight measured by GPC of 1,000 to 50,000. More specifically, it is a polymerizable oligomer represented by the following structural formula having an allyl group at the molecular end. -(CORCOOBO)-structure-A- (CORCOO) x-Z-O-CORCOO- structure-B (wherein R is an organic residue derived from a divalent carboxylic acid having 2 to 18 carbon atoms, x Is an integer of 2 or more and 6 or less, Z is an organic residue derived from a polyol having x + 1 hydroxyl groups and having 3 to 8 carbon atoms, and B is derived from a diol having 2 to 20 carbon atoms. Represents a divalent organic residue.)

The carbon number used as a raw material here is 2 to 18
The divalent carboxylic acid consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, β-methyladipic acid, pimelic acid, corkic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, Undecanecarboxylic acid, dodecanedicarboxylic acid, 1,2- or 1,3- or 1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, diphenyl-
p, p'-dicarboxylic acid, diphenyl-m, m'-dicarboxylic acid, 1,4- or 1,5- or 2,6- or 2,
7-naphthalene dicarboxylic acid, diphenylmethane-p,
p'-dicarboxylic acid, diphenylmethane-m, m'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, p-phenylmethane-m, m'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, p -Phenylenediacetic acid, p-carboxyphenylacetic acid, methylterephthalic acid, tetrachlorophthalic acid and the like. Particularly, aromatic dicarboxylic acids having high symmetry such as terephthalic acid and isophthalic acid are preferable for increasing Tg after curing.

Specific examples of the diol having 2 to 20 carbon atoms include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol and neopentyl. Glycol, 1,5-pentanediol, hexamethylene glycol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, undecamethylene glycol, dodecamethylene glycol, tridecamethylene glycol, eicosamethylene glycol, hydrogenation Bisphenol-A, 1,
4-cyclohexanedimethanol, 2-ethyl-2,5
-Saturated glycol consisting only of carbon such as pentanediol, 2-ethyl-1,3-hexanediol and styrene glycol, and ethylene oxide adduct of diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol and bisphenol-A, Also included are divalent saturated alcohols containing ether groups such as propylene oxide adducts of bisphenol-A, and glycols containing bromine such as bromoneopentyl glycol.

Specific examples of the polyol having 3 to 8 carbon atoms include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and sorbitol.

If the crystallinity of these allyl ester oligomers is too high, they cannot be dissolved in the unsaturated polyester resin and the curing reaction becomes non-uniform.
It is necessary to select a combination of raw materials so that the solubility does not become too low, especially when a highly symmetrical dibasic acid such as terephthalic acid or 2,7-naphthalenedicarboxylic acid is used. It is better to use propylene glycol, 1,3-butanediol, or dipropylene glycol as the diol component. Further, neopentyl glycol, an ethylene oxide adduct of bisphenol-A, and a propylene oxide adduct of bisphenol-A are particularly excellent diols for suppressing hydrolysis of the ester group after curing.

Regarding the ratio of structure-A to structure-B, too much component of structure-B causes the viscosity after compounding to be too high and gelation to occur too easily. Is preferably at least 50 mol% or more, more preferably 66 mol% or more. Of course, only Structure-A can be used.

It is important to note here that if the iodine value of the allyl ester oligomer to be blended is too high as expressed by the Wis method, not only the curing of the unsaturated polyester resin will be significantly delayed but also curing with an allyl group such as styrene will occur. When a monomer having poor properties is used, there is a problem that the entire system becomes cloudy. On the other hand, if the iodine value is too low, phase separation will occur in the polyester portion during curing, resulting in an opaque cured product like an ordinary low-shrinking agent. It is desirable that the iodine value of the polyallyl ester used therein is selected from the range of 2 to 45, more preferably 10 to 40. If the iodine value is within this range, an allyl monomer produced as a by-product during the synthesis of the allyl ester oligomer may be mixed.

If the molecular weight is too small, the effect of low shrinkage is not exerted, and if it is too large, the solubility in the unsaturated polyester resin is lowered and the viscosity is increased, and in some cases, phase separation occurs after curing. There is a drawback that it causes white turbidity. Therefore, the molecular weight of the allyl ester oligomer used is preferably selected from the range of 1,000 to 50,000, and more preferably 1500 to 20,000 as the polystyrene-reduced number average molecular weight measured by the GPC method.

The effect of these allyl ester oligomers is that the molecular weight is moderately high, so that the shrinkage after curing can be suppressed to a low level, and the allyl group at the end is copolymerized with the polyester resin, so that the curing is effected. It does not become phase opaque and does not become opaque. Further, when the iodine value is within the above-specified range, it can be said to be an effective additive without causing curing inhibition as in the case where a diallyl phthalate (DAP) monomer is blended with an unsaturated polyester.

The unsaturated polyester resin containing the allyl ester oligomer is generally known and is an unsaturated alkyd resin or vinyl ester dissolved in a radical-polymerizable monomer. As the unsaturated alkyd resin, various raw materials are known, and it is difficult to exemplify them unconditionally. For example, a divalent unsaturated carboxylic acid derivative, a divalent saturated carboxylic acid derivative and a divalent polyol are used. An unsaturated alkyd synthesized by performing a dehydration reaction can be used.

Examples of the divalent unsaturated carboxylic acid derivative used as a raw material include maleic anhydride, maleic acid, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and the like. As the divalent saturated carboxylic acid derivative, succinic acid, glutaric acid, adipic acid, β-methyladipic acid, pimelic acid, corkic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, Dodecane dicarboxylic acid, 1,4- or 1,5- or 2,6- or 2,7-naphthalene dicarboxylic acid, methyl terephthalic acid, chlorendic acid, tetrabromophthalic acid, tetrahydrophthalic acid,
Methyl tetrahydrophthalic acid, hexahydrophthalic acid,
Methylhexahydrophthalic acid, phthalic anhydride, endic acid anhydride, chlorendic anhydride, tetrabromophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride , Dimethyl terephthalate, etc., and divalent polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, 1,5-pentane. Diol, hexamethylene glycol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, undecamethylene glycol, dodecamethylene glycol, tridecamethylene glycol, eicosame Glycol, hydrogenated bisphenol -A, 1,4-cyclohexanedimethanol, 2-ethyl-2,5-pentanediol, 2-ethyl-1,3-hexanediol, styrene glycol,
Examples include diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, bisphenol-A ethylene oxide adduct, bisphenol-A propylene oxide adduct, dibromoneopentyl glycol, pentaerythritol diallyl ether, and glycerin monoallyl ether. it can.

The vinyl ester is a product obtained by reacting an epoxy resin with (meth) acrylic acid, which is also referred to as an epoxy acrylate. The epoxy resin used here is a bisphenol type, novolac type or aliphatic type. The type etc. are known. The synthetic methods and the physical property values of the polymer after the synthesis are described in detail in "Polyester resin hand hook" (Eiichiro Takiyama, published by Nikkan Kogyo Shimbun).

As the radically polymerizable monomer capable of dissolving these unsaturated alkyd and / or vinyl ester,
Styrene, vinyltoluene, α-methylstyrene, chlorostyrene, methyl methacrylate, ethyl acrylate,
Examples include n-butyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl isocyanurate, and the like, usually about 20 to 50% by weight in unsaturated alkyd or vinyl ester. To exist. Here, if the amount of the allyl ester oligomer is too large, there is a disadvantage that the curing becomes slow, the viscosity becomes high, and it becomes difficult for the inorganic filler to enter, which is not preferable. If the blending amount is too small, the effect of low shrinkage will not be obtained. Therefore, it is desirable to select the compounding amount from the range of 2 to 60 parts by weight, and more preferably 5 to 50 parts by weight of the total resin.

The thermosetting resin composition of the present invention can be used in the same manner as in the case of the conventional thermosetting resin composition, if desired, for example, a filler, a polymerization accelerator, a polymerization inhibitor, an internal release agent, a cup. A ring agent, a pigment, a flame retardant, a glass fiber, and other additives are compounded and used within a range that does not impair the characteristics of the composition,
Molding processability or physical properties of molded products can be improved.

As the method for molding the thermosetting resin composition of the present invention, known molding methods and molding conditions similar to those of conventional thermosetting resins can be applied as they are. That is, a casting method in which the composition of the present invention is poured into a mold and cured, an injection molding method or a transfer molding method in which the composition is heated to be in a fluidized state, and the composition is put into a mold and heat-cured, and the composition A compression molding method in which a product is heated and pressed to be cured in a mold, the composition is dissolved in an appropriate organic solvent, impregnated into a fibrous sheet, dried, and, if necessary, a fibrous sheet under a pressurized condition. Laminating method for curing resin in, coating method for applying fine powder or solution of the composition to a substrate and curing on the substrate, impregnating the composition solution into printing paper, etc., and drying, A molding method such as a decorative board molding method in which heat and pressure are applied to the substrate to cure it can be exemplified. The pressure when adopting the pressurizing condition is about 5 to 1000K.
A pressure such as g / cm ² can be exemplified. The heating temperature for curing during molding is about 40 to 12
A temperature such as 0 ° C. can be exemplified, but preferably 60 to 1
The temperature range is 00 ° C. If the curing temperature is too low, the curing speed will be slow, and it will not be possible to obtain a molded product with sufficient hardness.
On the other hand, if the temperature is too high, an unfavorable phenomenon such as cracking due to abrupt heat generation occurs. The thermosetting resin composition of the present invention can be used as a molding material in a wide range of fields such as artificial marble by utilizing its good transparency.

[0022]

INDUSTRIAL APPLICABILITY The present invention has improved reactivity by using an allyl ester oligomer having low reactivity in combination with an unsaturated polyester resin and a specific curing agent, and has the following features. Have. (1) Since a product having sufficient hardness can be obtained in a short time, physical properties of the cured product such as hardness, mechanical strength, and water resistance can be excellent, and productivity can be improved. (2) Even in a thick-walled molded product, a cracked product does not occur, and a molded product having low shrinkage and good dimensional stability can be obtained. (3) There is no coloring,
It is possible to obtain a molded product having a good transparency.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Reference Example-1 (Synthesis of Allyl Ester Oligomer) Diallyl terephthalate monomer (DATP) 5.0K was added to a 10 liter autoclave equipped with a reaction distillation apparatus.
g, propylene glycol (PG) 1.42 Kg, and dibutyltin oxide (DBO) 5.0 g were charged, and after sufficiently substituting with nitrogen, the mixture was heated to 180 ° C. to distill off the produced allyl alcohol. When the distillation rate of allyl alcohol became slow, the reaction system was depressurized to increase the distillation rate of allyl alcohol. When 90% of the theoretical amount of allyl alcohol was distilled, the reaction temperature was adjusted to 200
The reaction system was depressurized to 0.1 mmHg by a vacuum pump and the reaction was continued for 2 hours. The product obtained is 150
The sample was taken out on a vat at ℃, cooled to room temperature, and then pulverized to obtain a sample for evaluation.

Reference Examples 2-5 Allyl ester oligomers were synthesized in the same manner as in Reference Example-1, except that the starting materials were different. Table 1 shows the analytical values of the obtained allyl ester oligomer.

[Table 1] In addition, about the analysis of the allyl ester oligomer in (Table 1), it measured by the following method.

A) Method for determination and determination of iodine value Allyl ester oligomer was precisely weighed in the range of 0.30 to 1.0 g, put in a 200 ml iodine flask, and set to 30 m.
Add 1 l of chloroform to completely dissolve the sample. To this, exactly 20 ml of Wijs reagent (7.9 g of iodine trichloride and 8.2 g of iodine are dissolved in 200 to 300 ml of glacial acetic acid and then both solutions are mixed to make 1 liter) is added with a whole pipette. Then, 10 ml of 2.5% mercuric acetate glacial acetic acid solution is added, and the reaction is completed by leaving it in the dark for 20 minutes.

5 ml of newly prepared 20% KI solution
Was added as an indicator, and 0.1N-
Titrate with sodium thiosulfate standard solution. At the same time, perform a blank test. The iodine value was calculated by the following formula.

[0027]

[Equation 1] A: Number of ml of 0.1N-sodium thiosulfate solution required for blank test B: Number of ml of 0.1N-sodium thiosulfate solution required for this test f: Potency of 0.1N-sodium thiosulfate solution s : G of sample

B) Method of determining Mn and Mw by GPC Mn and Mw in terms of polystyrene are measured by GPC. SHODEX column AC-80P, 802, 80
One of each of 4,806 is connected in series in this order, chloroform is used as a solvent, and measurement is performed at a temperature of 25 ° C. and a flow rate of 1.0 ml / min. First, at least 10 kinds of commercially available standard polystyrenes having known average molecular weights were used, and the retention times of the DATP monomers and their respective retention times were determined. A calibration curve was prepared by approximating the relationship between the average molecular weight and the retention time with a cubic curve or a polygonal line. 20 mg of a sample is dissolved in 20 ml of chloroform, and 0.5 ml is injected into a column through a line filter using a loop injector. The obtained elution curve data is automatically calculated in a data processing machine such as Shimadzu CR-3A based on the calibration curve prepared in (3) to obtain Mn and Mw. Here, the peak is divided at intervals of 10 seconds, the molecular weight of each dividing point is Mi, and the height of the peak is Hi,
It was calculated by the following formula.

[0029]

[Equation 2]

Examples 1 to 6 and Comparative Examples 1 to 4 The unsaturated polyester resin, the allyl ester oligomer synthesized in Reference Example 1, the curing agent, and the filler were compounded at the compounding ratio (parts by weight) shown in Table 2 (Table 2). did. With respect to these compositions, the curing characteristics, the hardness of the cured product, the amount of residual styrene, and the color difference of the cured product were determined by a JIS method, a casting method, and a curing test using a curast meter. The results are shown in (Table 3).

[Table 2]

[Table 3] The curing agent and the procedure of the curing test in (Table 2) and (Table 3) are as follows.

A) Curing agent As the curing agent, products manufactured by NOF CORPORATION were used, and the abbreviations, trade names and chemical names are shown in (Table 4).

[Table 4]

B) Procedure of Curing Test 1) Curing Test by JIS Method Each characteristic value was determined as follows from a curing exothermic curve obtained by a method using a test tube having an inner diameter of 18 mm according to JIS-K-6901. . Gelation time (GT): Time to reach oil bath plus 5 ° C after immersion in oil bath Minimum curing time (CT): Time to reach maximum exothermic temperature after immersion in oil bath Maximum exothermic temperature ( PET): Maximum exothermic temperature during curing Pot life (PL): Time until gel formation at 30 ° C

2) Casting method A predetermined amount of the resin compound after vacuum treatment for 2 to 2.5 minutes was injected into two glass plates having a 5 mm-thick tephron spacer inserted therein, and air was applied at 80 ° C. It was cured in an oven to prepare a 70 × 100 × 5 mm test piece. At the same time, a thermocouple was inserted to measure the curing characteristics. After reaching the maximum exothermic temperature, leave it for another 10 minutes and take it out.
The Barcol hardness, color difference and residual styrene content were determined.
GT, CT and PET as curing characteristics were determined in the same manner as the JIS method. Barcol hardness: Measured with a GYZJ-934 model Barcol hardness meter. Color difference: Measured with a color difference meter manufactured by Nippon Denshoku Industries Co., Ltd. Residual styrene amount: About 5 g of the hardened material that has been fragmented is precisely weighed,
20 ml of ethyl acetate was added, extraction was carried out at 80 ° C. for 4 hours with an extraction device equipped with a cooler, and after cooling, about 0.03 g of n-decane was added as an internal standard substance. After filtering the extracted solution, the amount of residual styrene (% by weight) was quantified by gas chromatography.

3) Curast meter measuring method Each characteristic value was determined as follows from a torque curve obtained by using VPD (amplitude ± 1 ° each) manufactured by Orientec. T0: Time until torque appears T10: Time until 10% torque of Tmax is obtained T90: Time until 90% torque of Tmax is obtained Tmax: Maximum torque amount

As is clear from the comparison of the examples and comparative examples in (Table 2) and (Table 3), the tertiary alkylperoxy 2-elhexanoate of the present invention is a tertiary butylperoxy 2- As compared with L-hexanoate, it gives a cured product having a higher curing rate, a higher degree of completion of curing, a lower degree of coloring, and a higher hardness. Further, it gives a cured product having a longer pot life, a higher degree of completion of curing, a lower degree of coloring, and a higher hardness as compared with dipara tert-butylcyclohexyl peroxydicarbonate. Further, as compared with benzoyl peroxide, it gives a cured product which has a higher degree of completion of curing, a lower degree of coloring and a higher hardness. Furthermore, it can be seen that it has an excellent feature that the amount of the curing agent added is small.

Examples 7 to 11 and Comparative Examples 5 to 9 Unsaturated polyester resin, allyl ester oligomer synthesized in Reference Example at the compounding ratio (parts by weight) shown in (Table 5),
Curing characteristics, hardness of the cured product, residual styrene content, and color difference of the cured product were determined by a curing test by a casting method after adding a curing agent and a filler, and the results are shown in (Table 6).

[Table 5]

[Table 6]

As is clear from the comparison of the examples and comparative examples in (Table 5) and (Table 6), the tertiary hexyl peroxy 2-ethylhexanoate of the present invention is a compound of tertiary butyl peroxy 2- It can be seen that, as compared with ethyl hexanoate, a cured product having a higher curing rate, a higher degree of completion of curing, and a lesser degree of coloring is provided.

Examples 12 and 13, Comparative Examples 10-1
3 In the compounding ratio (parts by weight) shown in (Table 7), unsaturated polyester resin, allyl ester oligomer synthesized in Reference Example,
150x with a curing agent, low shrinkage agent and / or filler
The product was poured into an FRP mold in the shape of a bath having a size of 200 × 80 mm and a thickness of 10 mm for the entire molded product, and cured in an air oven at 80 ° C. for 1 hour to obtain a molded product. The evaluation results are shown in (Table 8).

[Table 7]

[Table 8]

The evaluation was carried out as follows. Volume Shrinkage Ratio The specific gravity of the resin compound before curing is measured using a pycnometer. Then, this was poured into a test tube having a volume of about 20 ml, the upper part of the test tube was tightly plugged, and then allowed to stand in an oil bath at 80 ° C. to proceed with curing. Then, after curing,
The cured product was taken out from the test tube, and the specific gravity of the cured product was measured by a solid pycnometer (SGM-SH-200-1 manufactured by Shimadzu Corporation).
The volume shrinkage rate (%) of the cured product was determined by the following equation. Volume contraction rate = {1- (specific gravity of resin compound / specific gravity of cured product)} × 100 Generation of cracks The presence or absence of cracks generated in the above-mentioned molded product was visually determined. Total Light Transmittance According to JIS-K7105 (Plastic optical property test method), the total light transmittance of the above-mentioned molded product was measured using a direct-reading haze meter manufactured by Toyo Seiki Seisakusho. Transparency The above-mentioned molded product was placed on the printed matter, and it was judged whether or not the font was visible from the upper part of the molded product. ◎: The font can be confirmed and the font can be read. ○: The font can be checked, but the font cannot be read. ×: The font cannot be checked.

As is clear from the examples and comparative examples of (Table 7) and (Table 8), the resin composition of the present invention was compared with the case where tert-butyl 2-ethylhexanoate was used. ,
Excellent in coloring degree and curing completeness. It is also found that the transparency is superior to that using the low shrinkage agent, and further, the crack resistance is superior to the one using neither the low shrinkage agent nor the allyl ester oligomer.

Claims (4)

[Claims] 1. The degree of unsaturation expressed by (a) iodine value is 2.
-45, the polystyrene-converted number average molecular weight measured by GPC is 1000 to 50,000, and the allyl ester oligomer is 2 to 60% by weight, (b) the unsaturated polyester resin is 40 to 98% by weight, and (a) + (b ) Of 10
With respect to 0 part by weight, (c) the following general formula: A thermosetting resin composition comprising 0.1 to 10 parts by weight of a tertiary alkylperoxy 2-ethylhexanoate represented by the formula (wherein R represents a methyl group, an ethyl group, or a tertiary butyl group). 2. The method according to claim 1, wherein instead of the component (c), (c ′) has the following general formula: (In the formula, R represents a methyl group, an ethyl group, or a tertiary butyl group), and 0.1 to 10 parts by weight of a tertiary alkylperoxy 2-ethylhexanoate and a dialkylperoxydicarbonate of 0.05 to A thermosetting resin composition comprising 5 parts by weight. 3. The degree of unsaturation expressed by iodine value is 2 to 45.
2 to 60% by weight of an allyl ester oligomer having a polystyrene-reduced number average molecular weight of 1,000 to 50,000 measured by GPC and an unsaturated polyester resin 40.
To 100 parts by weight of a thermosetting resin composition of 98% by weight, the following general formula: (In the formula, R represents a methyl group, an ethyl group, or a tertiary butyl group), 0.1 to 10 parts by weight of a tertiary alkylperoxy 2-ethylhexanoate is added, and
A method for curing a thermosetting resin composition, comprising curing at a temperature of 120 ° C. 4. The curing agent according to claim 3, having the following general formula: (In the formula, R represents a methyl group, an ethyl group, or a tertiary butyl group), and 0.1 to 10 parts by weight of a tertiary alkylperoxy 2-ethylhexanoate and a dialkylperoxydicarbonate of 0.05 to A method for curing a thermosetting resin composition, which comprises adding 5 parts by weight.