JPS59122515A - Low shrinkage unsaturated polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the titled composition having low molding shrinkage and excellent strength and surface flatness, by using specific amounts of a specific unsaturated polyester, p-methylstyrene and a p-methylstyrene polymer as essential components. CONSTITUTION:The objective low shrinkage unsaturated polyester resin composition is prepared by compounding (A) 25-75pts.wt. of an unsaturated polyester having an unsaturation degree of 1.5-5.0 and an acid value of 18-40 and obtained by reacting (i) an acid component containing (a) terephthalic acid and/or isophthalic acid and (b) one or more unsaturated acids selected from the group of maleic anhydride, maleic acid and fumaric acid with (ii) a glycol component such as ethylene glycol with (B) 75-25pts.wt. of p-methylstyrene and (C) 5- 20pts.wt. of a p-methylstyrene polymer (having a number-average molecular weight of 2,000-1,000,000), and if necessary, adding a filler (e.g. calcium carbonate), a reinforcing material (e.g. glass fiber), etc. to the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an unsaturated polyester resin composition that exhibits small volume shrinkage upon curing.

Molded products made by adding and kneading fillers such as glass fiber and calcium carbonate to unsaturated polyester resin are susceptible to distortion and cracking, as well as problems with sink marks and exposed glass fibers on the surface of the molded product. However, all of these are due to shrinkage during resin curing. Conventionally, a method to solve this problem is to mix other thermoplastic resins such as polystyrene and polymethyl methacrylate into unsaturated polyester resin with a high degree of unsaturation and cure it to create a non-shrinkage type. It has now been possible to obtain molded products that do not cause this.

In this way, by mixing unsaturated polyester resin with a high degree of unsaturation and thermosetting resin as a low shrinkage agent, a low shrinkage effect can be achieved, and the ratio of unsaturated polyester resin and heat radiation resin can be changed. in.

The shrinkage rate can be changed arbitrarily.

In general, increasing the ratio of heat radiation and other resins will reduce the shrinkage rate, but the strength of the molded product will decrease.

Therefore, when reducing shrinkage using conventional methods, it was not possible to achieve both low shrinkage and strength.

The present invention has been made in view of these points, and its purpose is to provide an unsaturated polyester resin composition to which a heat radiation resin is added that achieves both low shrinkage and molded product strength. be.

The present invention provides an unsaturated product obtained by reacting an acid component containing terephthalic acid and/or inophthalic acid with one or more unsaturated acids selected from the group consisting of maleic anhydride, maleic acid and fumaric acid with a glycol component. degree (number of moles of unsaturated acid contained in 1.000!i' of unsaturated polyester)
15-5.0. Unsaturated polyester 2 with acid value 18-40
5 to 75 parts by weight, 75 to 25 parts by weight of para-methylstyrene, and para-methylstyrene polymer (number average molecular weight 2,
000 to 1,000,000) to a low shrinkage unsaturated polyester resin composition containing 5 to 20 parts by weight.

In the present invention, by using the above unsaturated polyester, para-methylstyrene, and para-methylstyrene polymer, an unsaturated polyester resin composition is provided that exhibits less strength loss than before and provides molded products with low shrinkage. Ru.

The unsaturated polyester in the present invention includes either or both of terephthalic acid and isophthalic acid, one or more acid components of maleic anhydride, maleic acid, and fumaric acid, and ethylene glycol, diethylene glycol, propylene glycol, and diglobylene glycol. , butylene glycol, neopentyl glycol, hequinlene glycol, water-added bispheno-jlzA, λ2'-cy(4
- and doroquin chloroboxyphenyl) propane, 2.2'
- Obtained using a glycol component such as di(4-hydroxyethquinphenyl)propane. The degree of unsaturation (number of moles of unsaturated acid contained in 1,000y- of unsaturated polyester).

The reason why the value is 1.5 to 5.0 is that if it is less than 1.5, the low shrinkage effect of the para-methylstyrene polymer cannot be sufficiently exhibited.
This is because when it exceeds 0, the content of saturated acid (terephthalic acid or isophthalic acid) decreases, and the strength of the cured product does not improve. The reason why the saturated acid is limited to terephthalic acid or inophthalic acid is to sufficiently exhibit the low shrinkage effect.

If the acid value of the unsaturated polyester obtained is less than 18, the effect of the low shrinkage imparting agent cannot be sufficiently exhibited.

If it exceeds 40, the strength of the cured product will not improve.

The above-mentioned unsaturated polyester in the present invention can be produced by a known method.

Paramethylstyrene is particularly used as the α,β-ethylenically unsaturated monomer in order to provide low shrinkage.

In the present invention, the thermoplastic resin is limited to paramethylstyrene polymer. Its number average molecular weight is 2,000-1
,000,000, but 10,000-200,
000 is preferred. If the number average molecular weight is less than 2,000, the shrinkage reduction effect cannot be sufficiently exhibited.

This is because if it exceeds i, ooo, ooo, the compatibility with the unsaturated polyester deteriorates, and the low shrinkage effect cannot be sufficiently exhibited.

The paramethylstyrene polymer in the present invention is.

It can be manufactured by already known methods.

In the present invention, the reason why unsaturated polyester is limited to 25 to 75 parts by weight and paramethylstyrene is limited to 75 to 25 parts by weight is as follows.
If the unsaturated polyester is less than 25 parts by weight, curing shrinkage of para-methylstyrene becomes large, and even if a para-methylstyrene polymer is used, the shrinkage cannot be compensated for, resulting in dust.

This is because if the amount exceeds 75 parts by weight, the low shrinkage effect of the para-methylstyrene polymer cannot be sufficiently exhibited.

In the present invention, the unsaturated polyester and paramethylstyrene are used in a total amount of 100 parts by weight.

The reason why the para-methylstyrene polymer is limited to 5 to 20 parts by weight is that if it is less than 5 parts by weight, the low shrinkage effect cannot be sufficiently exhibited, and if it exceeds 20 parts by weight, the low shrinkage effect may not be achieved, but on the contrary, the strength cannot be maintained. This is because it becomes insufficient.

The low shrinkage unsaturated polyester resin composition of the present invention is cured using a curing agent. As a curing agent, methyl ethyl ketone peroxide, 1-butyl (-benzoate,
Examples include Pennzoyl var.

In addition, the resin composition of the present invention may optionally contain fillers such as calcium carbonate, talc, silica sand, silicic acid, aluminum hydroxide, barium sulfate, and reinforcing materials such as glass fiber, carbon fiber, and organic fiber. may be used together.

Other 9 commonly used pigments, softening agents, etc. may also be used as necessary.

The low-shrinkage unsaturated polyester resin composition of the present invention has a small molding shrinkage rate, which makes it possible to produce molded products with strong strength and excellent surface smoothness.

Detailed explanation of the present invention, Example 1 (1) 1.10 mol of fluoropylene gellicol, 15 mol of maleic anhydride, 0.5 mol of terephthalic acid, resulting acid value 30. Degree of unsaturation (unsaturation) Polyester i, oo
A 70% by weight p-methylstyrene solution of an unsaturated polyester of 2,7 (the number of moles of unsaturated acid contained in oy- is the same) was prepared.

+21 Acid value 30. obtained from 1.10 moles of 7'ropylene glycol, 0.5 moles of maleic anhydride, and 0.5 moles of terephthalic acid. A 70% by weight styrene solution (Bl was adjusted) of an unsaturated polyester with an unsaturation degree of 2.7.

(317" Obtained from 1.10 mol of robylene glycol and 1.0 mol of maleic anhydride. Acid value: 30. Unsaturation: 6.
A 70% by weight halamethylstyrene solution of unsaturated polyester No. 1 (C1) was prepared.

(4) Polystyrene (manufactured by Asahi Dow, Styron 666) was dissolved in styrene at a ratio (weight) of 1.1,
Poise's polystyrene solution (Dl was obtained).

(5) 50 parts by weight of rose methyl styrene, 1 part by weight of polyvinyl alcohol, and 300 parts by weight of water were placed in a flask No. 11, heated while stirring with a stir bar, kept at 80°C, and a polymerization reaction was carried out for 8 hours. . After 8 hours, the granular paramethylstyrene polymer obtained was passed through raw silk, washed with water, dried, and then dissolved in polyparamethylstyrene at a ratio of 1 part (by weight).

A 200 poise polyvinarmethylstyrene solution fE) was prepared. The molecular weights at this time were ioo and ooo.

These resin solutions and the materials shown in Table 1 were mixed into the meals shown in Table 1 (
Part by weight) was mixed to create a Nokluk molding compound. The obtained Norm ζ molding powder was molded under the conditions shown at the bottom of Table 1, and the properties of the molded product are shown in Table 1.

As shown in Table 1, the properties of the molded articles obtained from the resin compositions of the present invention are smaller in shrinkage and stronger than those obtained from the unsaturated polyester resin compositions using styrene monomers.

Example 2 (1) 0.50 mol of furopylene gellicol, 0.55 mol of neopentyl glycol, 1.0 mol of maleic anhydride
Acid value obtained from moles: 30. 60% by weight 8% paramethylstyrene solution of unsaturated polyester with degree of unsaturation 5.7 (F)
adjusted.

(21 (60 parts by weight tyrene solution of the unsaturated polyester obtained in 11 (Gl was adjusted).

These resin solutions and the materials shown in Table 1 were mixed together as shown in Table 1 (
parts by weight) to prepare a bulk molding compound. The obtained Kurumolding compound was molded under the conditions shown at the bottom of Table 2, and the properties of the molded product are shown in Table 2.

As shown in Table 2, the characteristics of the molded article obtained from the resin composition of the present invention are that the shrinkage rate is smaller and the strength is higher than that of the molded article obtained from the unsaturated polynisder resin composition using a styrene monomer.

-12( )

Claims (1)

[Claims] 1. Degree of unsaturation obtained by reacting a glycol component with an acid component containing terephthalic acid and/or isophthalic acid and one or more unsaturated acids selected from the group consisting of maleic anhydride, maleic acid, and fumaric acid. (Number of moles of unsaturated acid contained in 1.0OOy- of unsaturated polyester)1.
5-5.0. Unsaturated polyester 25 with acid value 18-4o
~75 parts by weight, 75 to 25 parts by weight of halamethylstyrene and paramethylstyrene polymer (number average molecular weight 2,0
00-1,000,000) 5-20 parts by weight of a low-shrinkage unsaturated polyester resin composition.