JPH06128490A - Thermosetting molding material composition - Google Patents

Abstract

PURPOSE:To obtain a compound resin capable of providing an in-mold coated molding excellent in adhesion to a coating material, i.e., a thermosetting molding material. CONSTITUTION:This thermosetting molding material composition for carrying out the in-mold coating is composed of (a) a thermosetting resin, (b) a radical polymerization initiator, (c) a filler and (d) a curing suppressor. Any of one or more compounds selected from the group consisting of 5-20C SH group- containing compounds, alpha-methylstyrene, stilbene, 4-phenoxystyrene, cumene and 4-methyl-2,4-diphenyl-pentene-1 and monoterpenic hydrocarbons are preferred as the curing suppressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin which is useful as a compound resin in an in-mold coating molding method in which a coating layer is formed on one side of a resin molded product formed in a predetermined shape using a split mold. The present invention relates to a molding material composition.

[0002]

2. Description of the Related Art In molding a resin molded product represented by a thermosetting resin bathtub or a panel, a synthetic resin coating layer is formed on one surface side, for example, on the inner surface side in the case of a bathtub. There is a known method, for example, a method called an in-mold coating method.

This method uses a pair of split molds (generally composed of a male mold and a female mold) consisting of a fixed mold and a movable mold, and a lump or sheet-shaped resin molding material (BMC or SMC) between them. , Hereinafter, may be simply referred to as a molding material), mold clamping is performed, and heat and pressure are applied to form a resin molded product having a predetermined shape. Then, between one surface of the resin molded product and the mold surface. In addition to the advantage that the molding and coating are performed using the same apparatus and in a series of steps, the surface is beautifully coated and coated. This method is characterized in that a resin molded product having excellent smoothness can be obtained.

On the other hand, on the other hand, it is difficult to obtain sufficient adhesion between the molded product and the coating material, and therefore various studies have been made even now. For example, JP-A-60-234
No. 43, No. 60-221437, No. 60-470.
No. 11 and JP-A No. 1-126316 show the results of study on the composition of the coating material, but a sufficient one has not been obtained yet.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and is a compound resin capable of obtaining an in-mold coated molded article excellent in adhesiveness with a coating material, that is, a heat resin. It is intended to provide a curable molding material.

[0006]

Means for Solving the Problems According to the present invention which has been able to achieve the above object, a thermosetting molding material composition for performing in-mold coating comprises (a) a thermosetting resin and (b) a radical. The gist is that it is composed of a polymerization initiator, (c) a filler, and (d) a curing inhibitor. The curing inhibitor has 5 to 5 carbon atoms.
20 SH group-containing compounds; α-methylstyrene, stilbene, 4-phenoxystyrene, cumene, 4-methyl-
It is preferably any one or more compounds selected from the group consisting of 2,4-diphenyl-pentene-1; monoterpene hydrocarbons.

[0007]

In order to improve the adhesion between the coating material and the resin molded product and to obtain an in-mold coated molded product having a good appearance, the inventors of the present invention have not completed the curing of the molding material when injecting the coating material. At the same time, it has been found that it is necessary that the curing of the molding material has progressed to some extent before the injection of the coating material. For example, if the molding material is uncured, the coating material may be mixed into the molded product. In addition, even if an attempt is made to inject the in-mold coating material during the time when the curing of the molding material has progressed to a certain extent but is not completed, it is difficult to grasp the timing of injection because this time period is short, and adhesion is difficult. Often, only poor quality was obtained. Therefore, in order to obtain an in-mold coated molded product having good adhesion, it is important to continue the state (semi-cured state) at the stage where the resin molding material has been cured to some extent. As a result of various investigations by the present inventors based on these findings, if a specific curing inhibitor is added to the molding material, the semi-cured state of the molding material can be maintained for a long time, and an in-mold coated molded article can be obtained. It was revealed that the adhesiveness of the in-mold coated molded article can be greatly improved without lowering the physical properties such as the strength. The present invention will be described in detail below.

The thermosetting molding material of the present invention comprises (a) a thermosetting resin, (b) a radical polymerization initiator, (c) a filler, and
(d) It consists of four components, a curing inhibitor. First
The thermosetting resin (a) is generally SMC or BMC.
Any thermosetting resin used as the compound resin can be used regardless of the type. Specific examples thereof include unsaturated polyester resins, (meth) acrylic modified unsaturated polyester resins, phenol resins, epoxy resins, urethane resins, vinyl ester resins, urethane modified vinyl ester resins, diallyl phthalate resins and the like.

Examples of the radical polymerization initiator (b) include ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides,
Known radical polymerization initiators such as alkyl peresters, percarbonates, and peroxyketals can be used, and the amount thereof is 0.1 to 10 parts by weight with respect to 100 parts by weight of the thermosetting resin. , Preferably 0.5-5
Parts by weight.

The filler (c) is usually SMC or BMC.
For example, calcium carbonate, clay, talc, barium sulfate, aluminum hydroxide, hollow ceramics, hollow glass and the like can be used. The proper usage amount is 30 to 600 parts by weight with respect to 100 parts by weight of the thermosetting resin. Further, a fibrous reinforcing material such as glass fiber, carbon fiber or organic fiber may be added if necessary, and it is preferable to use 3 to 50 parts by weight of the reinforcing material with respect to 100 parts by weight of the thermosetting resin. .

Examples of the curing inhibitor (d) include SH group-containing compounds such as mercaptans having 5 to 20 carbon atoms, thioglycols and SH group-containing silicates; α-methylstyrene, stilbene, 4-phenoxy. One or more phenolic compounds selected from the group consisting of styrene, cumene and 4-methyl-2,4-diphenyl-pentene-1; monoterpenes such as terpinolene, limonene, α-pinene, β-pinene and myrcene ( A terpene) hydrocarbon having 10 carbon atoms may be used alone or in combination of two or more.

The hardening phenomenon of the radical polymerization type thermosetting molding material is the time until gelling (hereinafter, gelling time GT
And the time to complete curing (hereinafter, the minimum curing time M
CT) and the time therebetween, that is, the time from gelation to completion of curing (hereinafter, may be referred to as reactive CG), but good adhesion as described above. In order to obtain an in-mold coated molded product having properties, it is necessary to keep the state of the stage where the resin molding material has been cured to some extent, that is, to lengthen CG. By adding the above-mentioned specific curing inhibitor to the molding material composition of the present invention, it became possible to make CG twice as long or longer. It is considered that this is because the curing inhibitor captures radicals to become relatively stable radicals, weakens the ability to initiate the polymerization, and causes the polymerization to proceed gently. The proper use amount of these curing inhibitors is 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the thermosetting resin. If the amount of the curing inhibitor is less than 0.1 parts by weight, the suppressing effect will not be sufficiently exerted, and if it is added in excess of 10 parts by weight, curing failure will occur and it will be difficult to obtain a high-performance molded product.

[0013]

The present invention will be described in more detail with reference to the following examples, but the following examples do not limit the present invention.
All modifications and implementations that do not depart from the spirit of the description below are included in the technical scope of the present invention. In the examples, "parts" are based on weight.

Example 1 Bisphenol-based unsaturated polyester resin (epolac
RF-1, manufactured by Nippon Shokubai Co., Ltd.) 100 parts, aluminum hydroxide 300 parts, zinc stearate 4 parts, mercaptopropyltrimethoxysilane (curing inhibitor) 1 part, t-butyl perbenzoic acid 1 part, magnesium oxide 1 Parts and 45 parts of glass chops were kneaded with a kneader and aged at 40 ° C. for 48 hours to obtain a molding material (BMC-1).

Example 2 BMC-2 is the same as Example 1 except that 1 part of 4-methyl-2,4-diphenyl-pentene-1 is used instead of using mercaptopropyltrimethoxysilane. Got Example 3 BMC-3 was obtained in the same manner as in Example 1 except that 1 part of limonene was used instead of using mercaptopropyltrimethoxysilane.

Comparative Example 1 As a comparative example, a comparative BMC was obtained in the same manner as in the example except that no curing inhibitor was used. In order to know the curing characteristics of these molding materials, 300 mm x 300 m with a thickness of 10 mm
A flat plate of m was molded at an upper mold forming temperature of 130 ° C. and a lower mold of 120 ° C., and the results are shown in Table 1.

[0017]

[Table 1]

Next, vinyl ester resin (Epolak RF
-1051: made by Nippon Shokubai Co., Ltd.) 1 part zinc stearate, 1 part t-butylperbenzoic acid and 2 parts finely divided silica 2
Using the in-mold coating material obtained by mixing the parts by high speed stirring,
In-mold coating was performed under the following conditions.

Injection method: The mold is opened after the primary curing, and the coating material is injected and then repressurized to cure. Mold: 1000 × 650 mm flat plate Mold temperature: Upper mold 130 ° C., Lower mold 120 ° C. Molding pressure: 80 kg / cm ^{2 for} both primary and secondary processing Molded product thickness: 10 mm Coating thickness: 100 μm Primary curing: 200 seconds , 250 seconds, 300 seconds, 350 seconds Secondary curing: 200 seconds

The in-mold coated molded product thus obtained was subjected to a cross-cutting test based on JIS K-5400 to evaluate the adhesion in the vicinity of the center (A) of the flat plate molded product and in the vicinity of the corners (B). In addition, the appearance was visually determined, and Table 2 shows the respective results. However, when the primary curing time is less than 200 seconds, the curing of the molding material is insufficient and the injected in-mold coating material penetrates into the molding material, resulting in a poor appearance of the molded product.
The above physical properties were examined when the primary curing time was 200 seconds or more.

[0021]

[Table 2]

As is clear from Table 2, in the examples using the curing inhibitor of the present invention, the time zone in which sufficient adhesion can be obtained is 150 seconds (between 200 seconds and 350 seconds). On the other hand, in the comparative example, it can be seen that the adhesiveness deteriorates in Comparative Examples 1-2 to 1-4 in which the coating material was injected after the primary curing exceeded 250 seconds. It can be said that the molded products of the examples have little variation in adhesion and are very useful in the production of large molded products.

Examples 4 to 7 In Example 1, BM was prepared by using α-methylstyrene instead of mercaptopropyltrimethoxysilane.
C-4 was created. Further, similarly, those using stilbene, 4-phenoxystyrene, and cumene as the curing inhibitors were designated as BMC-5, 6, and 7, respectively. Using these molding materials and the above-mentioned in-mold coating material, in-mold coating molding was performed under the same molding conditions as above. Adhesion and appearance were evaluated in the same manner as above, and the results are shown in Table 3.

[0024]

[Table 3]

Example 8 In Example 2, 100 parts of bisphenol unsaturated polyester resin was added to 70 parts of bisphenol unsaturated polyester resin and vinyl ester resin (Epolak RF-1).
(002G: manufactured by Nippon Shokubai Co., Ltd.) The composition was the same as in Example 2 except that the content was changed to 30 parts, and the mixture was kneaded and aged under the conditions described in Example 1 to obtain BMC-8.

Example 9 BMC-9 was obtained by using 30 parts of a urethane-modified vinyl ester resin derived from hydroxyethyl methacrylate and 2,4-tolylene diisocyanate in place of the vinyl ester resin in Example 8.

Example 10 Instead of the vinyl ester resin in Example 8, an iso type unsaturated polyester resin (acid value 20, viscosity 9 poise)
BMC-10 with 30 parts of epoxy modified unsaturated polyester resin derived from glycidyl methacrylate
Got Using these molding materials and the above-mentioned in-mold coating material, in-mold coating molding was performed under the same molding conditions as above. Adhesion and appearance were evaluated in the same manner as above, and the results are shown in Table 4.

[0028]

[Table 4]

As is clear from Tables 3 and 4, Examples 4 to 10 using the curing inhibitor of the present invention have a time zone in which sufficient adhesion can be obtained for 100 to 150 seconds. It can be said that it is also very useful in the production of large-sized molded products with little variation.

Examples 11 to 12 BM was carried out in the same manner except that 2 parts of 4-methyl-2,4-diphenyl-pentene-1 used in Example 2 were added.
C-11 was obtained. Also, 5 parts of 4-methyl-2,4-diphenyl-pentene-1 was added to obtain BMC-12. B
In-mold coating molding was similarly performed on MC-11 and 12, and the adhesion and appearance were evaluated, and the results are shown in Table 5.

[0031]

[Table 5]

Also in Examples 11 and 12, when the curing inhibitor of the present invention was used, the time zone in which sufficient adhesion could be obtained was 150 seconds or more. There was no variation in adhesion, but a slightly poor appearance was observed.

[0033]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, the time required for the thermosetting molding material to complete curing after gelation can be made extremely long. For this reason, the time for which the in-mold coating material can be injected becomes long, and it becomes possible to provide an in-mold coated molded product having stable and good adhesion.

Claims (4)

[Claims] 1. A thermosetting molding material composition for in-mold coating, comprising: (a) thermosetting resin, (b) radical polymerization initiator, (c) filler, and (d) curing. A thermosetting molding material composition comprising an inhibitor. 2. The curing inhibitor is S having 5 to 20 carbon atoms.
The thermosetting molding material composition according to claim 1, which is an H group-containing compound. 3. The curing inhibitor is α-methylstyrene, stilbene, 4-phenoxystyrene, cumene, 4
The thermosetting molding material composition according to claim 1, which is one or more compounds selected from the group consisting of -methyl-2,4-diphenyl-pentene-1. 4. The thermosetting molding material composition according to claim 1, wherein the curing inhibitor is a monoterpene hydrocarbon.