JP2798756B2 - Gel coating resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gel coat resin composition which is excellent in weather resistance, heat resistance and boiling resistance and can be molded at a high temperature.

[Related Art] A molded article using an unsaturated polyester resin is often subjected to gel coating for the purpose of imparting performance such as its appearance, scratch resistance and crack resistance.

Examples of the molded product to which the gel coat is applied include FRP and cast products such as bathtubs, wash basins and other home appliances, benches and ships and other outdoor products.

As the performance required for the gel coat resin, as mentioned above, emphasis is placed on the appearance, transparency to give a deep transparent feeling,
It has gloss, weather resistance, scratch resistance to make it less noticeable in the case of slight scratches, crack resistance, and water resistance, heat resistance and boiling resistance for use around water such as bathtubs.

Conventionally, unsaturated polyester as a resin for gel coating,
Resins such as unsaturated epoxy esters are used, and JP-B-47-19880 discloses a method of improving the scratch resistance by blending an unsaturated epoxy resin and an unsaturated polyester resin, and Japanese Patent Application Laid-Open No. 57-3992. In the gazette, blends of melamine resins and the like are reported.

In general, the amount of gel coat resin used is very small, only a few percent of the entire molded product, so that it is possible to use expensive special resins, and JP-A-62-297308 discloses the use of acrylic urethane resin. It is reported that the scratch resistance and the abrasion resistance are improved.

Originally, the performance of molded products obtained from SMC and BMC is
Since it largely depends on the performance of the compound used as MC, it requires a low shrinkage technology to improve the surface smoothness and gloss.

However, when the shrinkage is reduced, the transparency and the depth often tend to be lost.

Although a gel coat may be applied in order to obtain a sense of transparency and depth, there is a problem that conventional gel coat resins cannot be used for molding at high temperatures.

[Problems to be Solved by the Invention] When a conventional gel coat resin is directly used for high-temperature mold molding, volatilization of a monomer occurs on the mold, thereby inhibiting surface curing and uncuring the gel coat thin film. Even if the surface touching the mold hardens, the surface touching the air remains uncured, and in this state SMC, BMC
There is a possibility that the gel coat layer may flow or break when the compound such as is pressed.

For this reason, it is necessary to have sufficient mold adhesion and resin strength at high temperatures to withstand this.

Therefore, an object of the present invention is to solve the above problems,
An object of the present invention is to provide a resin composition for gel coating for high-temperature mold molding, which is excellent in weather resistance, boiling resistance, scratch resistance, abrasion resistance, and moldability.

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found that an unsaturated polyester having a bisphenol skeleton and an air-drying property for imparting air-drying property (air-drying property). The present inventors have found that the above object can be achieved by a resin composition comprising an unsaturated polyester and an ethylenically unsaturated monomer as a reactive diluent, and have completed the present invention.

That is, the resin composition for gel coating of the present invention comprises: (A) an unsaturated polyester having a bisphenol skeleton
100 parts by weight, (B) 50 to 350 parts by weight of air-drying unsaturated polyester, and (C) based on the total weight of the ester components of (A) and (B)
It is characterized by containing 10 to 110% by weight of an ethylenically unsaturated monomer.

As the unsaturated polyester having a bisphenol skeleton used in the present invention, a raw material having a bisphenol skeleton, for example, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct,
Some are formed from epoxy resin, bisphenol A, hydrogenated bisphenol A, and the like. These starting compounds are reacted with an acid component together with other glycol components, if desired. This reaction method is a method generally used for synthesizing an unsaturated polyester or vinyl ester.

The air-drying unsaturated polyester used in the present invention,
It is obtained by using an allyl ether as a glycol component raw material, a cycloaliphatic unsaturated polybasic acid as an acid component raw material, or a modified dicyclopentadiene.

The addition amount of these air-drying unsaturated polyesters is 50 to 350 parts by weight based on 100 parts by weight of the unsaturated polyester having a bisphenol skeleton. If the amount is less than 50 parts by weight, it is insufficient to maintain the air-drying property, and if it exceeds 350 parts by weight, the performance as a gel coat resin composition may be lost.

Examples of the ethylenically unsaturated monomer used in the present invention include, for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, propyl methacrylate, isopropyl methacrylate Methacrylic acid and its esters such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate and methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate and acrylic Acrylic acid and its esters such as isopropyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, acrylic acid, and others, vinyl acetate, acrylonitrile, and acrylic Amide, methacrylamide, styrene, alpha-methyl styrene, and the like.

Further, as the ethylenically unsaturated monomer having a relatively low odor, methoxydiethylene glycol methacrylate, methoxytetraethylene glycol methacrylate, methoxypolyethylene glycol methacrylate,
β-methacryloxyethyl hydrogen phthalate,
β-methacryloxyethyl hydrogen succinate, nonylphenoxyethyl methacrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxypolyethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxypolyethylene glycol acrylate,
β-acryloyloxyethyl hydrogen phthalate, β-acryloyloxypropyl hydrogen phthalate, β-acryloyloxyethyl hydrogen succinate, butoxydiethylene glycol acrylate, nonylphenoxyethyl acrylate, and the like.

Additives for these ethylenically unsaturated monomers are 10-110
The amount is preferably 20 to 80 parts by weight. Ten
If the amount is less than 10 parts by weight, the effect is weak.

The resin composition for gel coating of the present invention can optionally contain a crosslinking agent. Furthermore, the resin composition for gel coating of the present invention further improves air drying properties by containing a fatty acid cobalt or the like which has been conventionally used as a curing accelerator for an unsaturated polyester resin. However, considering the coloring of the resin and the discoloration after molding, it is not preferable to add too much, and when it is added, it is 0.05 to 0.3 parts by weight based on 100 parts by weight of the resin composition for gel coating.

The gel coat resin composition of the present invention has excellent workability, curability, and strength not only at room temperature but also for high-temperature mold molding, and can be adequately used as a gel coat for BMC and SMC, and has high gloss. Thus, a deep and excellent molded product can be obtained.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

The compositions (amounts by weight) shown in the following table were used as the resin composition for gel coating, the unsaturated polyester was used as the main molding material, and the upper mold temperature was 13
Molding was performed at 5 ° C., a lower mold temperature of 140 ° C., and a press pressure of 100 kg / cm ² .
The results are shown in the table.

 The symbols in the table are as follows.

H6700: Vinyl ester resin manufactured by Mitsui Toatsu Chemicals, Inc. R2150: Bis-unsaturated polyester resin manufactured by Mitsui Toatsu Chemicals, Inc. PN101: Air-drying unsaturated polyester resin manufactured by Mitsui Toatsu Chemicals, Inc. TMPT: Trimethylolpropane Trimethacrylate curing (curing condition on the mold) ・: Good foam removal when applying gel coat resin, and completely cured.

・: Good foam removal when applying gel coat resin, but uncured part remains partially.

B: Poor foam removal at the time of gel coat resin application, most of uncured portions.

X: Poor foam removal when applying gel coat resin, no curing at all.

Film breakage (a phenomenon in which the gel coat layer breaks due to pressure when the main molding material is press-molded after the gel coat has hardened).

 ○ ・ ・ The end is cut off.

 △ ・ ・ The whole is finely cut.

X: Cuts occurred on the entire surface and were washed away toward the end.

Flow (a phenomenon in which the gel coat layer is pushed away by pressure when the main molding material is press-formed after the gel coat is cured) ◎: No flow at all.

 ○ ・ ・ The edge part flows.

 △ ... More than half of the whole flow.

 ×: It does not flow completely.

[Effects of the Invention] The resin composition for gel coating of the present invention is based on an unsaturated polyester having a bisphenol skeleton and has air drying properties, so that it has excellent curability on a mold, and has excellent properties such as SMC and BMC. Gloss and depth can be imparted to the press-formed product without causing flow, film breakage, and the like during press-forming.

Continuation of front page (56) References JP-A-3-200822 (JP, A) JP-A-1-318003 (JP, A) JP-A-63-273660 (JP, A) JP-A-1-292016 (JP) , A) JP-A-60-123529 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08F 283/01 C08L 67/06 C09D 167/06

Claims (1)

(57) [Claims] (A) 100 parts by weight of an unsaturated polyester having a bisphenol skeleton, (B) 50 to 350 parts by weight of an air-dried unsaturated polyester, and (C) the total weight of the ester components of (A) and (B). By standard
A resin composition for gel coating, comprising 10 to 110% by weight of an ethylenically unsaturated monomer.