JPH04164911A - Polyester resin composition, production of resin used therein, moldings comprising same, and production of the moldings - Google Patents

Abstract

PURPOSE:To obtain a polyester resin composition improved in curability, yellowing resistance and heat resistance by mixing a specified polyester resin with a photopolymerization initiator and an organic peroxide without using any cobalt salt of an organic acid. CONSTITUTION:95-80 pts.wt. carboxyl-terminated polyester is mixed with 5-20 pts.wt. epoxy compound having an alpha, beta-unsaturated carboxylic acid ester group in air in the presence of optionally a solvent and a polymerizable monomer to obtain a polyester resin. The resin is mixed with 0.1-8 pts.wt., per 100 pts.wt. solid matter of the resin, photopolymerization initiator, an organic peroxide, desirably decomposable at 80 deg.C or below [e.g. bis(t-butylcyclohexyl) peroxydicarbonate] and optionally an extender pigment, a filler, a tackifying agent, a flow modifier, etc., to obtain the title composition.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is mainly used in the production of molded products that require aesthetic appeal, such as bathtubs, table counters, washstands, and marble-like artificial marble that requires an extremely light color. polyester resin composition with excellent yellowing resistance, gel coat resin,
The present invention relates to a method for producing the resin used therein, a molded article using the same, and a method for molding the same.

(Prior art) Radical curing resins, such as unsaturated polyester resins,
Vinyl ester resins can be cured by heating, but if this were to be done industrially, a large heating device would be required and the cost would be high, so there is a need for a method that allows molding at as low a temperature as possible. However, in order to cure these curable resins at or near room temperature, an organic peroxide such as ketone peroxide is used as a curing agent, and an organic acid salt of cobalt (narethene) is used as a curing accelerator. acid salts, octylate salts) should be used. However, when cobalt naphthenate is used, for example, the coating film of the molded article has an undesirable drawback that it yellows over time. For example, in the case of artificial marble, which is required to have an extremely light color, discoloration during use is not preferable because it greatly reduces its commercial value. In particular, since gel coat resin constitutes the surface layer of a molded article, discoloration of this layer must be avoided. However, the use of such cobalt salts is undesirable from the viewpoint of yellowing of the resin, but until now it has been impossible to effectively cure the resin at room temperature or low temperature without using cobalt salts. , which is the current situation.

(Problems to be Solved by the Invention) The present invention addresses the shortcomings of these conventionally known unsaturated polyester resins, that is, a resin composition with improved curability, yellowing resistance, and heat resistance, a gel foot resin, and a resin composition for use therein. The purpose is to provide a manufacturing method, a molded article using the same, and a method for molding the same.

(Means for Solving the Problems) The present inventor has made numerous attempts to avoid the use of cobalt salts. As a result, in order to prevent coloration during room temperature curing, we discovered that a photocuring method that does not use organic acid salts of cobalt, which is a curing accelerator for peroxide curing agents, was better, and as a result of intensive research on photocurable resins. , we have completed the present invention.

That is, the present invention provides (a) a polyester resin obtained by reacting a polyester having a carboxyl group terminal with an epoxy compound containing an α/β-unsaturated carboxylic acid ester group, and (b) a photopolymerization initiator. , (c) a polyester resin composition comprising an organic peroxide, a gel coat resin containing no organic acid salt of cobalt, and further comprising 95 to 80 parts by weight of polyester and α
・A method for producing a polyester resin (a) characterized by reacting in air with 5 to 20 parts by weight of an epoxy compound containing a β-unsaturated carboxylic acid ester group, and using this composition in a gel coat layer. The resin composition is applied to a characteristic molded product and a mold, and the resin composition is irradiated with light to harden to the desired degree of hardening, and the resin is poured to the required thickness with or without lining with glass fiber. The present invention provides a molding method characterized by heating and curing the gel coat layer and the casting layer after molding.

(Structure) The polyester resin of the present invention is an unsaturated polyester obtained as a saturated dicarboxylic acid, an unsaturated dicarboxylic acid, or one of the dicarboxylic acids and a polyhydric alcohol, or an unsaturated polyester obtained as a saturated polyester. Or α/β to the carboxyl group of saturated polyester
- unsaturated polyester (meth)acrylate obtained as a reaction component of an epoxy compound containing an unsaturated carboxylic acid ester group, such as a (meth)acrylate group;
Saturated polyester/(meth)acrylate; unsaturated polyester/(meth)acrylate is preferred for use in gel coats. Further, as a representative example of the epoxy compound containing an α/β-unsaturated carboxylic acid ester group, glycidyl methacrylate can be mentioned.

Examples of the saturated dicarboxylic acid having no active unsaturated group include orthophthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid, and sebacic acid. Isophthalic acid and terephthalic acid are preferably suitable for boiling resistance. Examples include fumaric acid, maleic acid, itaconic acid, etc., which have active unsaturated groups.

Examples of polyhydric alcohols include ethylene glycol,
Propylene glycol, butylene glycol 1,5-bentanediol, 1,6-bentanediol, 2. 2
-dimethyl-1,3-propanediol, diethylene glycol, triethylene glycol, bisphenol-
Propylene oxide adduct of A, bisphenol-A
It is obtained by using polyhydric alcohols such as ethylene oxide adducts as alcohol components.

The polyester resin preferably consists of 5 to 20% by weight of an epoxy compound containing an α/β-unsaturated carboxylic acid ester and 95 to 80% by weight of a polyester having a carboxyl group at the end. In the reaction between this epoxy compound and the polyester having carboxyl group terminals, the molar ratio of epoxy groups and carboxyl groups does not necessarily have to be equal, and the presence of free epoxy compounds is allowed.

It is convenient to carry out this reaction in a solvent or a polymerizable monomer and use it as is, but it is also possible to synthesize without a solvent.

Styrene used in the present invention is important in terms of workability and hardness of the cured coating film, and is preferably 0 to 60 parts by weight, preferably 20 parts by weight.
~50 parts by weight.

In the present invention, a polymerizable monomer such as styrene is generally used, but is not limited to styrene, and may include vinyltoluene, α-methylstyrene, chlorostyrene, hydrarylyl cyanurate, etc. The above-mentioned resin-crosslinkable navinyl monomers or vinyl oligomers such as allyl compounds may be used alone or in combination.

The use of polymerizable monomers such as styrene in the present invention is important in terms of workability and hardness of the cured coating film, and the amount used is as follows:
The amount is 0 to 60 parts by weight based on 0 to 40 parts by weight of the resin solid content, preferably 20 to 50 parts by weight based on 50 to 80 parts by weight of the resin solid content.

As the photopolymerization initiator, the following may be considered, and these may be used alone or in a mixed system. For example, benzoin ethers such as benzoin alkyether, benzophenone, benzyl, benzophenone such as methyl orthobenzoyl benzoate, benzyl dimethyl ketal, 2
．． 2-shed beef diacetophenone, 2-hydroxy-2
-Methylpropiophenone, 4'-isopropyl-2-
Acetophenones such as hydroxy-2-methylpropiophenone and 1,1-dichloroacetophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-
Thioxanthone such as isopropylthioxanthone,
Examples include benzyl ketals such as hydroxy-cyclohexyl-phenyl ketone.

The amount used is usually 0 per 100 parts by weight of resin solid content.
．． The amount is preferably 1 to 8 parts by weight, preferably 1 to 5 parts by weight.

The organic peroxides used in the present invention include, for example, ketone peroxide, hydroperoxide, sialic ruber oxide, and diacylperoxide described in the technical material "Organic Peroxides" 3rd edition published by NOF Corporation. oxides or peroxydiesters, and diazo compounds such as azobisisobutyronitrile or azobisvaleronitrile. Among these, since it is practically preferable to perform the operation of forming a cast layer at a temperature of 100°C or lower, a type that decomposes at a relatively low temperature, for example, 80°C or lower, is desirable. Among these, bis(1-butylcyclohexyl) peroxydicarbonate (Kayaku Akzo™ product name Percadox 16) is preferred in view of both the appropriate curing temperature and handling safety.

The composition of the present invention includes various additives used in gel coats, such as organic and/or inorganic extender pigments, fillers, adhesion agents such as silane coupling agents and titanium coupling agents, Flow modifiers such as leveling agents, chicken tropic agents, and slip agents, polymerization inhibitors, antistatic agents, and dyeability imparting agents can also be used. When casting and curing resin, fillers are usually used in combination with the casting resin to provide a suitable degree of transparency and to prevent cracks caused by heat generated during curing and molding. Glass powder, aluminum hydroxide, calcium carbonate, etc. are commonly used as fillers.

Although the present inventors have found that the photocuring method is very effective for curing gel coat layers, they have also discovered major drawbacks. The problem is that when it is completely photocured to exhibit sufficient physical properties as a gel coat, peeling tends to occur between the next FRP lamination and casting layer. This drawback could be prevented by polishing the gel coat to improve its adhesion, but the process would become complicated and practical industrialization was impossible.

In order to avoid this drawback, in the present invention, instead of completely curing by photo-curing, we take post-processes into consideration and cure to the desired degree of hardening, and then line it with glass fiber or do not do it if necessary. After casting the resin to the desired thickness, it is optimal to heat and harden the gel coat layer and the casting layer. α・
The degree of polymerization of epoxy compounds containing a β-unsaturated carboxylic acid ester group can be very easily controlled by light. If the amount is less than 5% by weight, the ultraviolet curability is not good, and if it is more than 20% by weight, complete curing will occur and peeling will occur.

Moreover, cracks often occur during molding. Therefore,
In order to obtain appropriate curability, the charging ratio is important.

The purpose can also be achieved by performing the final complete curing with an organic peroxide.

Since the curing by light can be easily controlled, by selecting the composition of the resin, the curing of the gel coat layer or the subsequent laminated portion can be controlled to the required degree. After the gel coat layer or, if necessary, the laminated portion has been photocured, casting is performed using a radical curing resin containing a radical curing agent, and this is heated and cured together with the gel coat layer. As a result, the cast part and the gel coat part are cured and bonded together, and a strong molded product without peeling can be obtained. The heating temperature for curing is 100
''C, preferably about 70 to 80C.

Next, in order to explain the present invention in more detail, Examples are shown below, where "parts" and "%" are based on weight.

Example 1 [Production of polyester resin for gel coat] Neopentyl glycol 208 was added to a 410 flask equipped with a stirrer, condenser, thermometer, and gas inlet tube according to a conventional method.
g, 332 g of isophthalic acid and 240 g of hydrogenated bisphenol-A were heated to 220°C in a nitrogen stream to react until the acid value reached 2. Then, 116 g of fumaric acid was added and the reaction was continued at the same temperature until the ester reached an acid value of 70. Then, the temperature was lowered to 170° C., and 142 g of glycidyl methacrylate was added in an air atmosphere, followed by stirring for 2 hours. The acid value is 2
It became. Next, the temperature was lowered to 140''C, and 0.16 g of hydroquinone and 632 g of styrene were added to obtain an unsaturated polyester resin (A-1).

[Formation of gel coat layer] Aerosil R was added to 100 parts of polyester resin (A-1).
After adding 2 parts of -200 (Japan Aerosil ■ product) and kneading to give thixotropic properties, to 100 parts of this resin, 2 parts of Irgacure 181 (Japan Ciba Geigy product) as a photocuring agent, and Perrydox as a peroxide. 16 (Kayaku Akzo ■ product) was added to prepare a photocurable gel coat composition (a-1). 30cmX coated with mold release agent
A gel coat composition was applied on a glass plate of 30ca+X 0°5c++. Apply with a bar coater to a thickness of 5 mm, wait for the coating to become uniform, and apply it for about 15 minutes at a distance of 30 cm below the sun lamp (Stanley Electric product).
After irradiation for 30 minutes, the gel coat layer was cured to the extent that it was dry to the touch.

[Casting, heat curing] The obtained gel coat layer was used as one side, and a 2 mm white colored FRP layer using a glass mat was placed on another side at an interval of 10 mm. To this mixture, 200 parts of glass frit (product of Nippon Ferro Co., Ltd.), 15 fl of styrene, and 1.5 parts of Parryki Dox 16 (product of Kayaku Akzo Co., Ltd.) were added to 100 parts of polyester resin, and the mixture was uniformly kneaded. After defoaming and casting, it was heated and cured together with the gel coat layer at 60"C for 2 hours and at 80"C for 4 hours. When molded after curing, a molded article (I) having a transparent gel coat layer on the surface was obtained.

Comparative Example 1 Cobalt naphthenate (
6% Co) and 0.1 part of gel coat composition (a-2
), and a molded product (n) was obtained by light irradiation, casting, and heat curing in the same manner as in Example 1.

Comparative Example 2 A gel coat composition (a-3) was prepared by removing the photopolymerization initiator from the gel coat composition (a-1), and the surface of the gel coat layer coated on a glass plate was coated with a polyester film having a thickness of 1°Oμ. After covering and heat curing at 8o0c for 5 hours, the film was removed and cast and heat cured in the same manner as in Example 1.
A molded article (m) was obtained.

Each molded product was cut into 15cm x 15cm pieces, and the gel coat layer was set on the inside in a boiling resistance testing device that had four circular holes with a diameter of 10cm on one side, and the temperature was 98 to 99.
A boiling test was performed at ℃. The results are shown in Table 1 below.

Table 1 Check the condition of the gel coat layer and select those with no change (
○), those in which sparkling occurred were rated as (△). Among the molded products shown above, only molded product I was actually usable.

(Effects of the Invention) The present invention contains a radical curing polyester resin containing a photocuring agent and an organic peroxide as a thermosetting agent as essential components, and does not contain an organic acid salt of cobalt as a curing accelerator. It is a resin composition, and by irradiating this resin with light and making it to the desired hardness to form a gel coat layer, a backing layer can be formed, or by forming a casting resin layer and curing it by heating, the durability of the gel coat layer can be increased. Molded products with excellent yellowing and peeling resistance can be obtained.

Claims (1)

[Scope of Claims] 1. (a) A polyester resin obtained by reacting a polyester having a terminal carboxyl group with an epoxy compound containing an α/β-unsaturated carboxylic acid ester group, (
A polyester resin composition characterized in that it does not contain (b) a photopolymerization initiator and (c) an organic acid salt of cobalt consisting of an organic peroxide. 2. Claim 1 characterized in that it is a gel coat resin.
polyester resin composition. 3. The polyester resin composition according to claims 1 and 2, wherein the solid content of the polyester resin (a) has an acid value of 20 or less. 4. Epoxy compound containing 95 to 80 parts by weight of polyester and α/β-unsaturated carboxylic acid ester group 5 to 2
0 parts by weight in air. 5. A molded article characterized in that the composition according to claim 1 or 2 is used for a gel coat layer. 6. Apply the resin composition of claims 1 and 2 to a mold, irradiate it with light to cure it to a desired degree of hardening, and then line it with glass fiber or pour the resin to the required thickness without lining it. A molding method characterized by heating and curing the gel coat layer and casting layer after molding.