JPH0216113A - Process for modifying unsaturated polyester resin - Google Patents

Abstract

PURPOSE:To make is possible to speed up the cycle of operation, to reduce coloration and to improve the heat resistance by curing an unsaturated polyester resin and a specific maleimide compound in the presence of a radical polymerization initiator at ordinary temperatures or under heating. CONSTITUTION:An unsaturated polyester resin (A) is obtained by blending 100pts.wt. (hereinafter merely pts.) unsaturated polyester with 5-70pts. vinyl monomer copolymerizable therewith (e.g. styrene). 100pts. component (A) and 0.5-100pts. maleimide compound of the given formula (wherein R1 is 1-18C alkyl or cycloalkyl; and R2-3 are each H, halogen, methyl or ethyl) (e.g. N- cyclohexylmaleimide) are cured in the presence of 0.1-10pts. radical polymerization initiator (e.g. benzoyl peroxide) at ordinary temperatures, that is, 10-30 deg.C or by heating to 50-200 deg.C.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides an unsaturated polyester resin for obtaining an unsaturated polyester resin that can be cycled up in a modification reaction, has excellent heat resistance, and has little coloring. This invention relates to a method for modifying.

<Prior Art> Unsaturated polyester resins are widely used as thermosetting molding materials for automobile parts, electrical parts, septic tanks, bathtubs, fishing boats, and the like.

However, the physical properties of conventional cured products are not necessarily sufficient, and from a comparison with thermoplastic engineering resins that have excellent moldability, it is possible to obtain cured products with better heat resistance and less coloring. A method for modifying unsaturated polyester resins is desired.

Conventionally, in order to improve the heat resistance of unsaturated polyester resins, methods such as increasing the degree of unsaturation of unsaturated polyester to increase crosslinking density, or adding fillers with higher heat resistance have been used. .

However, these methods have the following problems. In other words, changing the degree of unsaturation of unsaturated polyester causes disadvantages such as a decrease in physical properties other than heat resistance, such as impact resistance, and fillers also have a large effect on various properties, so the amount used must be limited. For example, there is a

<Problems to be Solved by the Invention> An object of the present invention is to provide a method for modifying an unsaturated polyester resin that has excellent heat resistance, has little coloration, and can be modified under a wide range of modification conditions. It is in.

<Means for Solving the Problems> According to the present invention, an unsaturated polyester resin comprising an unsaturated polyester and a vinyl monomer copolymerizable with the unsaturated polyester is provided.

Maleimide represented by the following general formula (I) (wherein R□ represents an alkyl group or cycloalkyl group having 1 to 18 carbon atoms, and R2 and R3 represent a hydrogen atom, a halogen atom, a methyl group or an ethyl group) A method for modifying an unsaturated polyester resin, which comprises adding 0.5 to 100 parts by weight of a compound to 100 parts by weight of the unsaturated polyester resin, and curing at room temperature or heating in the presence of a radical polymerization initiator. provided.

The present invention will be explained in more detail below.

The unsaturated polyester in the present invention is an unsaturated dibasic acid such as maleic anhydride or fumaric acid, or the unsaturated dibasic acid and phthalic anhydride or isophthalic acid.

A mixture of saturated dibasic acids such as adipic acid and tetrachlorophthalic anhydride, and ethylene glycol, propylene glycol, and 1,3-butylene gellicol.

Diethylene glycol, dipropylene glycol.

A polyhydric alcohol such as neopentyl glycol or bisphenol dioxyethyl ether is mixed in a conventional manner, preferably in a ratio of 1:0.5 to 2 mol, particularly preferably 1:1, under nitrogen, for example.

It can be obtained by condensation at 170 to 200°C. It is also possible to use commercially available unsaturated polyesters.

Examples of the vinyl monomer copolymerizable with the unsaturated polyester used in the present invention include styrene.

0-chlorostyrene, vinyltoluene, methyl methacrylate, diallyl phthalate, triallyl cyanurate,
Examples include diallylbenzenephosphonate, etc.
These can be used alone or in combination. The blending ratio of the vinyl monomer is 1 to 1 of the unsaturated polyester.
00 parts by weight, 5 to 70 parts by weight, particularly preferably 1
It is desirable that the amount is 0 to 60 parts by weight, and it is also possible to use commercially available unsaturated polyester resins.

The maleimide compound in the present invention has the following general formula (I)
It can be expressed as

In the formula, R4 represents a straight-chain alkyl group, a branched alkyl group, or a cycloalkyl group having 1 to 18 carbon atoms, and R2 and R3 represent a hydrogen atom, a halogen atom, a methyl group, or an ethyl group.

Examples of the maleimide compound represented by the general formula (I) include N-methylmaleimide, N-isopropylmaleimide, N-t-butylmaleimide, N-octadecylmaleimide, N-cyclohexylmaleimide, N-cyclohexyl (α- methyl)maleimide, N-cyclohexyl(α,β-dimethyl)maleimide, N-(2-methyl-cyclohexyl-1)maleimide, N-3-ethyl-cyclohexyl-1-maleimide, N-cyclododecylmaleimide , N-laurylmaleimide, N-dodecylmaleimide and the like can be preferably mentioned.

The unsaturated polyester resin 1 of the maleimide compound
The addition ratio per 0.00 parts by weight is 0.5 to 100 parts by weight, and if it is less than 0.5 parts by weight, no improvement in the heat resistance of the obtained cured product will be observed.

If it exceeds 100 parts by weight, the physical properties of the cured product will deteriorate, which is not preferable.

The method for modifying an unsaturated polyester resin in the present invention is a method in which a maleimide compound is added to an unsaturated polyester resin, and the mixture is cured at room temperature or by heating in the presence of a radical polymerization initiator.

Specifically, for example, it is desirable to mix and stir the unsaturated polyester resin and the maleimide compound to form a uniform solution, and if necessary, fillers such as glass fibers, fillers, and inorganic substances and/or Or a reinforcing agent can also be added. Next, a radical polymerization initiator such as an organic peroxide is added to the solution, and the method is heated and cured in a temperature range of 50 to 200°C, or a reducing agent is used in combination,
A method of curing at a low temperature of 10 to 30° C. or the like can be used.

As the organic peroxide which is the radical polymerization initiator,
For example, benzoyl peroxide, lauroyl peroxide, butyl peroxybenzoate, isopropyl peroxydicarbonate, 1,1-bis(butylpuroxy)-3゜3.5-1-limethylcyclohexane, dicumyl peroxide, 2, 5 dimethyl-2,5
-Heat-curing polymerization initiators such as di(7-butylperoxy)hexyne-3, cumene hydroperoxide/manganese oxide, methyl ethylphene peroxide/cobalt naphthenate, acetylacetone peroxide/ferric oxide, benzoyl peroxide/dimethylaniline Examples include room temperature curing type polymerization initiators such as. The amount of these used is preferably 0.1 to 10 parts by weight per 100 parts by weight of the unsaturated polyester resin.

<Effects of the Invention> According to the method for modifying unsaturated polyester resin of the present invention,
Since the time from gelation to hardening can be shortened, molding cycles can be increased. Furthermore, the resulting molded product has the advantage of significantly improved heat resistance and less discoloration.

<Example> Next, the present invention will be explained in more detail with reference examples, examples, and comparative examples, but the present invention is not limited thereto.

Reference Example 1 (Preparation of unsaturated polyester resin) Anhydrous malein 9 was placed in a 500 mQ four-loop flask equipped with a stirrer, thermometer, nitrogen gas blowing tube, and condenser.
18 g of phthalic anhydride, 178 g of propylene glycol, and 167 g of propylene glycol were added, and the mixture was heated under stirring while passing nitrogen gas at a flow rate of about 100 mQ/min. 15 in 1 hour
The temperature was raised to 0°C, and stirring was continued for an additional hour. Thereafter, the reaction temperature was raised and maintained at 210'C to distill off water of condensation.

Next, the acid value of the reaction solution was measured, and when the acid value reached 40, it was cooled. Next, 200 g of styrene monomer was added and stirred until a homogeneous solution was obtained. As a result, a pale yellow unsaturated polyester resin was obtained.

One color appearance (preparation of unsaturated polyester resin) 162 g of fumaric acid, 100 g of isophthalic acid, 79 g of propylene glycol and 109 g of neopentyl glycol
An unsaturated polyester with an acid value of 30 was synthesized in the same manner as in Reference Example 1, and then styrene monomer was added so that the styrene monomer concentration was 35% by weight to obtain an unsaturated polyester resin. To 100 parts by weight of the unsaturated polyester resin prepared in Reference Example 1, 10 parts by weight of N-cyclohexyl maleiside was added and dissolved. Next, 1.0 parts by weight of benzoyl peroxide was added and uniformly dissolved, and a curing reaction was performed according to JIS K-6901. Table 1 shows the curing temperature, physical properties of the cured product, degree of coloring, heat deformation temperature, etc. In addition, the degree of coloring was visually inspected, and the heat deformation temperature was determined by JIS.
A casting plate was separately prepared according to K-7207 and measured.

A modification reaction of an unsaturated polyester resin was carried out in the same manner as in Example 1 using the unsaturated polyester resin, maleimide compound and radical polymerization initiator shown in Table 1 and under the reaction conditions shown in Table 1. Then, the hardness, heat distortion temperature, and degree of coloring of the obtained cured product were measured. The results are shown in Table 1.

Hoshiki Toru 12±

Claims (1)

[Claims] An unsaturated polyester resin consisting of an unsaturated polyester and a vinyl monomer copolymerizable with the unsaturated polyester has the following general formula (I) ▲Mathematical formula, chemical formula, table, etc.▼...(I ) (In the formula, R_1 represents an alkyl group or a cycloalkyl group having 1 to 18 carbon atoms, and R_2 and R_3 represent a hydrogen atom, a halogen atom, a methyl group, or an ethyl group.) resin 10
A method for modifying an unsaturated polyester resin, which comprises adding 0.5 to 100 parts by weight to 0 parts by weight, and curing at room temperature or heating in the presence of a radical polymerization initiator.