JPS61213215A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To provide the titled composition suitable as a resin composition for in-mold powder coating, by compounding a specific spiroglycol di(meth)- acrylate with an epoxy (meth)acrylate and a polymerization catalyst. CONSTITUTION:The objective composition can be produced by mixing (A) the spiroglycol di(meth)acrylate of formula (R is H or CH3) obtained by the thermal reaction of 3,9-bis(1,1-dimethyl-2-hydroxyethyl) 2,4,8,10-tetraoxaspiro(5,5)undecane with (meth)acrylic acid and (B) an epoxy (meth)acrylate obtained by reacting an epoxy compound having at least one epoxy group in the molecule (e.g. bisphenol-type epoxy resin) with an alpha,beta-unsaturated monobasic acid at a weight ratio (A/B) of (90-20)/(10-80) and adding a polymerization catalyst to the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermosetting resin composition suitable as a resin composition for powder in-mold coating.

[Prior art and its problems]

Generally, FRP molded products with a gel coat layer are produced by spraying liquid gel coat resin such as unsaturated polyester resin, polyester acrylate resin, or epoxy acrylate resin with a gun onto the mold surface that has been heated to room temperature or about 60°C. Alternatively, after applying with a brush to form a gel coat layer, it can be obtained by a hand lay-up method, a spray-up method, or a casting method. However, productivity is low with this molding method, so after spraying or applying liquid gel coat resin to a heated mold, SMC (sheet molding compound) is applied.
, a method of placing BMC (bulk molding compound) or just a compound on top and pressure molding was investigated. However, since this molding method contains volatile polymerizable unsaturated monomers such as styrene monomers in the liquid gel coat resin, it significantly worsens the working environment and the volatilization of the monomers may cause It has the disadvantage that a gel coat layer having the desired performance cannot be formed.

In order to improve this drawback, a method has been developed in which diallyl phthalate monomer or its prepolymer, which has very low volatility, is used as a polymerizable unsaturated monomer in gel coat resin (Japanese Patent Publication No. 29745/1983). However, although this method improves the working environment, it has drawbacks such as the gel coat layer being easily yellowed when heated, being brittle, and having low surface hardness.

In order to improve these drawbacks, 3,9-bis(1,1
-dimethyl-2-hydroxyethyl)2゜4, 8.
10-Tetraoxaspiro(5,5)undecane (hereinafter referred to as ``spiroglycol'') and acrylic acid or methacrylic acid are heated to react. Acrylate” or [
We have found a powder coating composition containing an ethylenically unsaturated compound, ie, "spiroglycol dimethacrylate"), and a polymerization catalyst. (Special application 1978-178
No. 065).

This powder coating resin composition is sprayed into a heated mold, melted and cured, and then SMSMC1B or a compound (containing a resin and an inorganic filler) is placed and pressure molded to form the gel coat layer of the molded product. Although it has the characteristics of good transparency, little discoloration by heating, high hardness, and good weather resistance, it has the disadvantage that it is somewhat brittle and weak in impact resistance.

[Means to solve the problem]

The present inventors have completed the present invention as a result of intensive studies to improve the above-mentioned drawbacks.

That is, the present invention provides an ethylenically unsaturated compound (a) represented by the general formula (in the formula, R5 represents ■ or CH3), an epoxy compound having at least one epoxy group in the molecule, and α, β - Contains an epoxy (meth)acrylate (b) obtained by reacting an unsaturated unsaturated acid and base with a polymerization catalyst, (a) / (
It relates to a thermosetting resin composition characterized in that b) is 90 to 20 parts by weight/10 to 80 parts by weight.

The composition of the present invention is deposited in powder form in a mold heated to 90 to 200°C, melted and hardened to form a resin-rich layer (gel coat layer), and then applied to SMC, BMC, compounds, etc. It is used to obtain an integrated molded product by placing a resin member and press-molding it.

The ethylenically unsaturated compound (a
) is spiroglycol diacrylate or spiroglycol dimethacrylate represented by the above general formula, and is a pale yellow solid compound with melting points of 117-120°C and 83-87°C, respectively.

Further, the epoxy compound having at least one epoxy group in one molecule for producing the epoxy (meth)acrylate (b) component in the composition of the present invention refers to an epoxy resin having an epoxy equivalent of 130 or more. However, since the composition of the present invention is used in powder form, it is preferable to use an epoxy resin having an epoxy equivalent of 300 or more. Examples of such epoxy compounds include epichlorohydrin, methylepichlorohydrin, etc. Examples include condensates of epihalohydrin and bisphenol compounds or novolacs.

Here, as an example of a bisphenol compound, 2゜2-
Representative examples include bis(4-hydroxyphenyl)propane and 2,2-bis(4-hydroxyphenyl)methane. Novolacs include resorcinol,
Examples include tetrahydroxydiphenylmethane, a condensate obtained by reacting a phenolic compound such as phenol or cresol with formaldehyde. It is also possible to increase the epoxy equivalent by reacting an epoxy compound with a low epoxy equivalent with a phenolic compound.

These epoxy compounds can be used alone or in combination of two or more.

Examples of the α,β-unsaturated acid-base acid to be reacted with the above-mentioned epoxy compound include acrylic acid and methacrylic acid, and two or more of these may be used in combination. Furthermore, a saturated basic acid or a saturated polybasic acid can also be used in combination, if desired.゛In order to obtain the epoxy compound and α,β-unsaturated acid-base acid epoxy (meth)acrylate (b), the equivalent ratio of epoxy group to carboxyl group is in the range of 1:0゜8 to 1.2. The reaction is carried out under conditions known per se for the reaction temperature and other conditions, for example, the reaction is carried out at a temperature of 80 to 150°C in the presence of an esterification catalyst. As the esterification catalyst used here, known catalysts are used, such as secondary amines, tertiary amines, inorganic or organic acid salts of these amines, phthalate metal salts, metal nolorides, etc. Can be done.

Since the composition of the present invention is thermosetting, it is melted by heating at a temperature equal to or higher than its melting point or softening point, and then cured by a polymerization crosslinking reaction. Although it is necessary to use a polymerization catalyst in combination for this curing, it is necessary to appropriately select a catalyst having a different decomposition temperature in consideration of mold temperature, pot life, and gelation time. As this type of polymerization catalyst, organic peroxides such as acyl peroxide, ketone peroxy F1 acetyl peroxide, hydroperoxide, and ester peroxide are used. Two or more of these may be used in combination. The amount of these polymerization catalysts used is 0.5 to 3.0% by weight based on the composition.

In the composition of the invention, an ethylenically unsaturated compound (a
) and epoxy (meth)acrylate (b) are used in a weight ratio of 90 to 20 parts by weight/10 to 80 parts by weight, and (a
)/(b) exceeds 90/10, the brittleness of the gel coat layer, that is, the impact resistance, is not sufficiently improved, which is undesirable.On the other hand, when (a)/(b) is less than 20/80, ethylene The excellent properties of the sexually unsaturated compound (a), spiroglycol diacrylate or spiroglycol dimethacrylate, are not exhibited.

The compositions of the present invention generally contain ethylenically unsaturated compounds (
a), the epoxy (meth)acrylate (b) and the polymerization catalyst, and optionally a filler, are uniformly mixed in powder form, or the necessary components are mixed in a molten state, cooled, and then pulverized. It is obtained by making it into a powder and mixing a filler with it if desired.

In some cases, epoxy (meth)acrylate (b), a polymerization catalyst, and a filler are added to a mixture of a powdered ethylenically unsaturated metal material (a), a polymerization catalyst, and a filler if desired. It can also be obtained by mixing a mixture of The particle size of the composition of the present invention is generally preferably 200 microns or less.

The composition of the present invention may further contain colorants, inorganic or organic fillers, plasticizers, flowability modifiers, etc., if necessary.

〔Effect of the invention〕

The composition of the present invention has excellent performance as a powder coating resin composition for in-mold use, has little discoloration upon heating,
A molded product having a gel coat layer with high transparency and surface hardness (good weather resistance) can be provided.

〔Example〕

Examples of the present invention will be described below.

Reference Example 1 (Epoxy acrylate synthesis) A bisphenol-based epoxy resin (trade name:
Epicoat 288”, manufactured by Yuka Shell ■) 1148.8g
, 2.2-bis(4-hydroxyphenyl)propane 5
49.5 g of triphenylphosphine and 0.8 g of triphenylphosphine were charged and reacted at 160°C to 180°C for 2 hours to obtain a bisphenol-based epoxy resin with an epoxy equivalent of 1300.

This epoxy resin 1699.1g, acrylic acid 94.3g
g, 0.72 g of toluhydroquinone and 3.6 g of dimethylbenzylamine were charged into the same reactor as above 17
React at 0°C for 1.5 hours to obtain an acid value of 1.1 mgKOH/g.
of epoxy acrylate was obtained.

Reference Example 2 (Epoxy Acrylate Synthesis) In a reactor similar to Reference Example 1, 1641 g of a bisphenol-based epoxy resin with an epoxy equivalent of 2000 (trade name "Epicote 1007J, manufactured by Yuka Shell ■), 59 g of acrylic acid, and 0.68 g of toluhydroquinone were added.

Add 3.5 g of dimethylbenzylamine and heat at 170°C.
．． React for 5 hours and acid value 2. Omg KOH/g of epoxy acrylate was obtained.

Reference Example 3 Ethylenically unsaturated compound (a) [3100 parts of spiroglycol diacrylate, 1.0 part of Aerosil #300 (manufactured by Nippon Aerosil ■), Tribonox 29/40 (
1゜1-ditertiary-butylperoxy-3,3,5
-) Contains 40% Limethylcyclohexane] (manufactured by Kayaku Nouri ■) A powder obtained by mixing and pulverizing 2 parts was passed through a 200 sieve sieve to obtain a fine powder composition. rSGC
- I J.

Reference Example 4 100 parts of the epoxy acrylate powder obtained in Reference Example 1,
Aerosil #300 1°0 parts, Tribonox 29/
The powder obtained by mixing and pulverizing 2.0 parts of 40 was passed through a 200 mesh sieve to obtain a fine powder composition. Add this to rEAC
- IJ.

Reference Example 5 100 parts of the epoxy acrylate powder obtained in Reference Example 2,
Aerosil #300 1.0 part, Tribonox 29/
The powder obtained by mixing and pulverizing 2.0 parts of 40 was passed through a 200 mesh sieve to obtain a fine powder composition. Add this to rEAC
-2J.

Example 1 30 parts of the fine powder composition rEAC-IJ obtained in Reference Example 4 and 70 parts of the fine powder composition rSGC-IJ obtained in Reference Example 3 were mixed and passed through a 200 mesh sieve for powder coating. A composition was obtained. This is designated as “5EC-IJ.

Example 2 50 parts of the fine powder composition rEAC-IJ obtained in Reference Example 4 and 50 parts of the fine powder composition rSGC-IJ obtained in Reference Example 3 were mixed and passed through a 200 mesh sieve for powder coating. A composition was obtained. This is called "5EC-2J.

Example 3 70 parts of the fine powder composition rEAC-IJ obtained in Reference Example 4 and 30 parts of the fine powder composition rSGC-1 obtained in Reference Example 3 were mixed and passed through a 200 mesh sieve to form a powder. A coating composition was obtained. This is called "5EC-3J.

Example 4 50 parts of spiroglycol diacrylate, 50 parts of epoxy acrylate obtained in Reference Example 2, Aerosil #300
1.0 part was mixed, heated and melted at 150 to 160°C, cooled, and ground into powder. This powder 10
0 parts and 2.0 parts of the polymerization catalyst Tribonox 29/40 were mixed, pulverized, and passed through a 200 mesh sieve to obtain a powder coating composition. This will be referred to as rSEC-4J.

Each of the powder compositions obtained in Examples 1 to 4 and Reference Examples 3 to 5 and a diallyl phthalate prepolymer (rDAP-IJ) known for use in gel coats was mixed with 14
Spray into a mold at 5℃ to form a gel coat layer precursor with a thickness of 0.4 to 0. An FRP molded crystal was obtained in which was integrally formed on the surface. Surface gloss and heat resistance (surface discoloration, 180°C, 2 hours), surface hardness, thermal shock resistance (-30°C to 80°C for 10 minutes each, 0 cycles and 3 cycles each), Weather resistance (160 hours of weathering, no fading)
I looked into it.

The results are shown in Table-1.

As shown in the table, the surface hardness of the gel coat layer of the FRP molded product using the composition of the present invention is very high, the surface gloss is good, there is almost no heat discoloration, and the thermal shock resistance and weather resistance are also extremely excellent. There is.

Table-1 Voluntary writing of procedural amendments)

Claims (1)

[Claims] An ethylenically unsaturated compound (a) represented by the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (in the formula, R_1 represents H or CH_3) and an epoxy group in the molecule. It contains an epoxy (meth)acrylate (b) obtained by reacting at least one epoxy compound with an α,β-unsaturated basic acid, and a polymerization catalyst;
A thermosetting resin composition characterized in that (b) is 90 to 20 parts by weight/10 to 80 parts by weight