JPH0374424A - Unsaturated polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, containing an unsaturated polyester, crosslinking monomer and oligomer of specific styrenes and capable of suppressing an increase in resin temperature in hot molding, preventing the crosslinking monomer from evaporating and providing cured products without causing cracking. CONSTITUTION:The objective composition obtained by blending (A) 100 pts.wt. unsaturated polyester with (B) preferably 7-30 pts.wt. crosslinking monomer (e.g. styrene) and (C) preferably 7-50 pts.wt. oligomer of styrenes having preferably 300-1000 number-average molecular weight and 20-110g-I2/100g iodine value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention generally relates to unsaturated polyester resin &I! This relates to samurai, and in particular, to an unsaturated polyester resin composition that suppresses the rise in resin temperature during heat molding, prevents the evaporation of the crosslinking monomer blended, and provides a cured product without cracks. It is.

(Prior art and problems to be solved by the invention) Conventionally, unsaturated polyester resins have excellent mechanical properties, electrical properties, thermal properties, workability, etc.
Widely used in the fields of construction materials, transportation equipment, and industrial materials.

Unsaturated polyester resin is an unsaturated alkyd resin obtained by the condensation reaction of polybasic acid and polyhydric alcohol, and is mainly blended with crosslinking monomers, catalysts, accelerators, and various fillers to be thermoset. It is used as a sexual varnish.

The blending amount of such crosslinking monomer is generally 20 to 50% by weight, and styrene is most widely used because of its cost advantage and excellent properties. However, since styrene has a low molecular weight, it volatilizes during storage as a varnish or during heat curing, which has been pointed out to pose health problems for workers and local residents. In an attempt to solve this problem caused by volatilization, Japanese Patent Application Laid-Open No. 57-8215
As shown in the above publication, there is a method using styrene dimer as a crosslinking monomer. Although this method can solve the problem caused by styrene volatilization, the resulting cured product is soft and cracks occur over time, making it impossible to take advantage of the characteristics of the cured unsaturated polyester resin. It has the disadvantage of being stored away.

In addition, the reaction of heating and curing unsaturated polyester resin using a low molecular weight crosslinking monomer such as styrene as a crosslinking agent and an organic peroxide catalyst is an extremely exothermic reaction, so the resin temperature increases due to the heat of reaction. The temperature rises to over 200°C. At this time, unreacted low-molecular-weight crosslinking monomers volatilize, causing health and environmental problems, as mentioned above, but also because the maximum temperature of the resin during curing becomes too high. It has been pointed out that resins that are left to cool after being released from the mold have the disadvantage that stress accumulates inside them and cracks are likely to occur.

Therefore, the purpose of the present invention is to solve the above-mentioned problems of conventional crosslinking monomers, suppress the rise in resin temperature due to reaction heat during heat curing, prevent evaporation of crosslinking monomers, and prevent cracks from occurring. An object of the present invention is to provide an unsaturated polyester resin composition that can prevent the above problems.

(Means for Solving the Problems) In order to achieve the above object, the present inventors have conducted various studies and found that a low molecular weight The present inventors have discovered that by blending a styrene oligomer, it is possible to suppress heat generation during curing, prevent evaporation of crosslinking monomers, and prevent cracks from occurring after curing, and have completed the present invention.

That is, the present invention provides an unsaturated polyester resin composition containing an unsaturated polyester and a crosslinkable monomer, in which a low molecular weight compound is used to suppress heat generation during curing, prevent evaporation of the crosslinkable monomer, and prevent cracking after curing. The present invention relates to an unsaturated polyester resin composition characterized by containing a styrene oligomer.

In the present invention, the styrene oligomer has a number average molecular weight of 300 to 1000 and an iodine value of 20 to 1000.
110 g-1t/100 g is used. If the number average molecular weight is less than 300, an odor will be generated during heat curing of the unsaturated polyester, which is not preferable. On the other hand, when it exceeds 1000, the compatibility with unsaturated polyester resin decreases,
It is not possible to obtain a uniform resin, which is also undesirable.

Moreover, if the iodine value is less than 20 g -Is/100 g, the crosslinking density of the resin decreases and a resin having sufficient hardness cannot be obtained, which is not preferable. On the other hand, 110g1g
If it exceeds /100 g, the resulting cured resin is soft and cracks occur over time, which is also not preferred.

Styrenes used as raw materials for oligomers include various alkyl group-substituted styrenes such as styrene, α-methylstyrene, and P-methylstyrene, and these may be mixtures. The oligomer is obtained by mild polymerization using an acid catalyst or the like.

Furthermore, examples of the unsaturated polyester used in the present invention include polymers obtained by a condensation reaction of polyhydric alcohols and unsaturated polybasic acids.

Specifically, “Revolac 150” manufactured by Showa Kobunshi Co., Ltd.
11RJ, ``Revolac 1588QTJ,'' Polyset 9230 J manufactured by Hitachi Chemical Co., Ltd., and ``Ebi Cuff 5F 6 J manufactured by Nippon U-Pica Co., Ltd.''.

Further, the crosslinkable monomer used in the present invention may be any substance having an olefinic double bond in its molecule, and specifically includes styrenes such as styrene, α-methylstyrene, and p-methylstyrene; trimethylol. General-purpose crosslinking monomers for unsaturated polyesters include acrylic acid or methacrylic acid esters such as propane trimethacrylate and 2-hydroxyethyl methacrylate; and allyl ethers such as trimethylolpropane allyl ether and diallyl phthalate.

Next, the curing agent used for curing the unsaturated polyester resin composition of the present invention includes alkyl hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; Dialkyl peroxides such as dicumyl; diacyl peroxides such as benzoyl peroxide and acetyl peroxide; peracetic acid t
Examples include peracid esters such as -butyl and t-butyl perbenzoate.

In the resin composition of the present invention, it is preferable to add 7 to 50 parts by weight of a styrene oligomer to 100 parts by weight of the unsaturated polyester. The effect of preventing crack generation is not sufficient, and on the other hand, if it exceeds 50 parts by weight, the crosslinking density of the resin decreases and a resin having sufficient hardness cannot be obtained, which is not preferable.

Further, the crosslinking monomer is preferably added in an amount of 7 to 30 parts by weight based on 100 parts by weight of the unsaturated polyester.
If the amount is less than 30 parts by weight, the mixability of the resin will be poor and a resin with a uniform composition will not be obtained, while if it exceeds 30 parts by weight, an odor will be produced during heat curing or storage, which is not preferable.

Furthermore, the amount of curing agent used is 0.5 to 0.5 to
It is used within a range of 5% by weight. If it is less than 0.5% by weight, it will take a long time to cure the resin, so it is not practical. On the other hand, if it is more than 5% by weight, the properties of the resulting cured resin will not improve, so it is uneconomical. .

In addition to the above-mentioned essential components, the resin composition of the present invention may appropriately contain commonly used materials such as a curing accelerator, a polymerization inhibitor, and a filler, as required.

(Example) Next, the present invention will be specifically explained by giving examples and comparative examples.

z Arashiban 70 parts by weight of unsaturated polyester (trade name "Revolac 150" IRJ) manufactured by Kamishowa Kobunshi Co., Ltd., was added with styrene oligomer (number average molecular weight 340; iodine value 67 g-I).
t/100 g) 20 parts by weight, and 10 parts by weight of styrene monomer (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) as a crosslinking monomer.
Parts by weight of benzoyl peroxide (
1 part by weight of Reagent Special Grade (manufactured by Wako Pure Chemical Industries, Ltd.) was added and thoroughly stirred and mixed to obtain a varnish. This varnish is 18++nφ
Put it in a test tube of 180 am to a height of 100 am,
A thermocouple connected to a digital thermometer was set in the center of the varnish.

A varnished test tube with a thermocouple set at 80℃±0
．． The varnish was set in an oil bath whose temperature was adjusted to 5°C so that the entire varnish was immersed, and temperature changes at the center of the varnish were observed. The curing characteristics of the resin were evaluated according to JIS 6901, and the evaluation items and their meanings are as shown below.

■ Gelling time: resin center temperature from 65°C to 85°
The time required to rise to C.

■ Minimum curing time: The time required for the core temperature of the resin to reach its maximum point.

■ Maximum exothermic temperature: The temperature at which the center temperature of the resin reaches its maximum point.

In addition, cracks generated in the cured resin were visually observed immediately after curing and after the cured resin was taken out of the test tube and left in a desiccator at room temperature 20% R11 for 7 days, to determine the presence or absence of cracks.

The criteria for evaluation were (A) no cracks, (B) cracks partially, and (C) cracks throughout, grade 03.

Furthermore, the ease of mixing the resins was determined by allowing the varnish to stand at room temperature for 30 minutes before adding the curing agent, and visually determining the presence or absence of separation of each component. The evaluation criteria were in two stages: "separation" and "non-separation."

Furthermore, the presence or absence of evaporation of the crosslinking monomer due to the heat generated by the resin during curing can be determined by visually observing the inside of the test tube.
Judgment was made based on the presence or absence of resin odor during heat generation. The results are summarized in Table 1 below.

1: 1: The same procedure as in Example 1 was carried out except that the styrene oligomer (number average molecular weight 340, iodine value 67 g-Im/100 g) and styrene monomer were blended in the proportions shown in Table 1. Ta. The results of resin curing characteristics and appearance observation are summarized in Table 1.

30% of styrene monomer without using styrene oligomer
The same operation as in Example 1 was performed except that parts by weight were used.

The results of resin curing characteristics and appearance observation are summarized in Table 1.

Styrene oligomer (number average molecular weight 340, iodine value 67g-1 richness/100g) without using styrene monomer
The same operation as in Example 1 was performed except that 30 parts by weight of . The results of resin curing characteristics and appearance observation are summarized in Table 1.

Five blue group 1 Styrene dimer (1,3
-Diphenylbutene-1 richness 95-% L EF element value 1
11 g-I2/100 g) was used, and the same operation as in Example 1 was performed except that the mixture was blended in the proportions shown in Table 1. The results of hardening characteristics and appearance observation of 411 resin are summarized in Table 1.

(Effects of the Invention) As explained above, the unsaturated polyester resin composition of the present invention can suppress the rise in resin temperature due to heat generation during curing by incorporating a specific styrene cheek oligomer. It has been observed that it has the effect of preventing the evaporation of crosslinking monomers as well as the occurrence of cracks in the cured resin, and can be said to be a suitable resin composition as a substitute for conventional unsaturated polyester resins that have been prone to cracking, especially during molding. .

Claims (1)

[Claims] 1. An unsaturated polyester resin composition containing an unsaturated polyester and a crosslinkable monomer, which has a number average molecular weight in the range of 300 to 1000 and an iodine value of 20.
An unsaturated polyester resin composition characterized in that a styrene oligomer in the range of ~110g-I_2/100g is blended. 2. The amount of the styrene oligomer is in the range of 7 to 50 parts by weight per 100 parts by weight of the unsaturated polyester, and the amount of the crosslinking monomer is in the range of 7 to 50 parts by weight per 100 parts by weight of the unsaturated polyester. The unsaturated polyester resin composition according to claim 1, wherein the amount is in the range of 30 parts by weight.