JPH0559322A - Thermosetting resin composition for coat-molding in mold and coat-molded article - Google Patents

Abstract

PURPOSE:To obtain the subject composition useful for forming a base for the in-mold coating molding to form a coating layer on a base material in a mold and giving a molded article having a coating layer firmly bonded to a base material by compounding a specific compound to a resin component containing a thermosetting resin. CONSTITUTION:The objective composition is produced by compounding (A) a resin component containing a thermosetting resin (e.g. urethane acrylate resin) with (B) a compound selected from a compound having ethylenic double bond and -NH2 group (e.g. acrylamide) and a compound having ethylenic double bond, hydroxyl group and -NH group (e.g. N-methylol acrylamide) as an agent for improving the adhesivity to a coating layer. The amount of the compound in the resin component of the thermosetting resin is preferably 1-50wt.%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermosetting resin composition for in-mold coating molding, which is used for forming a base material for in-mold coating molding for forming a coating layer on a substrate in a molding die. And a coated molded article using the thermosetting resin composition for in-mold coating molding as a substrate.

[0002]

2. Description of the Related Art Recently, molded articles made of thermosetting materials have been
It is widely used in industrial parts as a substitute for metal parts. Above all, a sheet molding compound (hereinafter, abbreviated as SMC) or a bulk molding compound (hereinafter, abbreviated as BMC) is generally used. However, in a molded product obtained by molding SMC or BMC by heating and pressurizing in a molding die, surface defects such as pores, microcracks, sink marks or undulations tend to occur on the surface. When such surface defects are present, it is difficult to form a sufficient coating film even if the molded product is coated by a usual method.

Therefore, a so-called in-mold coating molding method has been proposed as a method for concealing the above-mentioned surface defects. For example, Japanese Patent Application Laid-Open No. 53-71167 discloses a method of forming a coating layer on a molded article by heating and pressurizing the SMC in the mold to semi-cure the SMC, then opening the mold and injecting a coating material. It is disclosed. On the other hand, JP-A-61-273
No. 921 discloses a method of forming a coating layer on the surface of a molded article by injecting a coating material at an injection pressure higher than the molding pressure and curing the same during compression molding.

[0004]

However, in the in-mold coating molding method described in the above-mentioned prior art, SM is used.
There is a problem that the adhesion between the base material made of C or BMC and the coating layer is not sufficient.

Accordingly, an object of the present invention is to provide a thermoplastic resin for in-mold coating molding, which is used for forming a base material for in-mold coating molding, which makes it possible to obtain a coated molded article having good coating layer adhesion. It is an object of the present invention to provide a resin composition and a coated molded article using the thermosetting resin composition for in-mold coating molding as a substrate.

[0006]

The invention of claim 1 of the present application is a thermosetting resin composition used for forming a base material for in-mold coating molding for forming a coating layer on a base material in a molding die. A compound having an ethylenic double bond and an --NH ₂ group in the molecule, and an ethylenic double bond, a hydroxyl group and an --NH-- group in the molecule in a resin component containing a thermosetting resin. Is a thermosetting resin composition for in-mold coating molding, which contains at least one compound selected from the compounds described in 1.

The invention of claim 2 of the present application is a coated molded article in which a coating layer is formed on a substrate, and a coating using the thermosetting resin composition for in-mold coating molding of claim 1 as a substrate. It is a molded product.

Examples of the compound having an ethylenic double bond and --NH ₂ group in the molecule used in the present invention include acrylamide: CH ₂ ═CHCONH ₂ , methacrylamide: CH ₂ ═CCH ₃ CONH ₂ , allylamine. : CH ₂ = CHCH ₂ NH ₂ , 2-amino-1,
1,3-Tricyano-1-propene: NCCH ₂ C (N
H ₂ ) = C (CN) ₂ , acryloguanamine:

[0009]

[Chemical 1]

And the like. Incorporating a compound having an ethylenic double bond and an --NH ₂ group in the molecule into the thermosetting resin is the adhesion to the coating layer of the thermosetting resin used for the base material as described later. To increase the ethylenic double bond and --N used in the present invention.
The total amount of the compound having an H ₂ group in the molecule is preferably in the range of 0.1 to 70% by weight, more preferably 1 to 50% by weight in the resin content of the thermosetting resin. ..

The reason is that if the amount is less than 0.1% by weight, the effect of improving the adhesion to the coating layer is not sufficient, and conversely, if the amount is more than 70% by weight, the content of allylamine In the case of such a liquid compound, the viscosity of the composition becomes too low, which makes it difficult to form SMC or BMC, and in the case of a solid compound such as (meth) acrylamide, the viscosity is high. This is because it tends to be difficult to obtain sufficient fluidity in the mold at the time of molding.

An ethinle double bond used in the present invention,
Examples of the compound having a hydroxyl group and an --NH-- group in the molecule include N-methylol acrylamide: CH ₂ ═
CHCONHCH ₂ OH, N-methylolmethacrylamide: CH ₂ ═CCH ₃ CONHCH ₂ OH, 1-allyl-3- (2-hydroxyethyl) -2-thiourea:
_{CH 2 = CHCH 2 NHCSNHCH 2 CH} 2 OH , and the like.

In the thermosetting resin, an ethylenic double bond,
The reason why the compound having a hydroxyl group and a --NH-- group in the molecule is contained is to enhance the adhesiveness between the thermosetting resin used for the substrate and the coating layer as described later, but it is used in the present invention. Ethylenic double bond, hydroxyl group and --NH
It is preferable that the total amount of the compound having a group in the molecule is 0.1 to 70% by weight, more preferably 1 to 50% by weight in the resin content of the thermosetting resin. The reason is that if it is less than 0.1% by weight, the effect of improving the adhesiveness with the coating layer is not sufficient, and conversely, if it is contained in excess of 70% by weight, the thermosetting resin composition is contained. This is because the viscosity of the product becomes too high, and it tends to be difficult to obtain sufficient fluidity in the mold during molding.

In addition to the thermosetting resin, the resin component of the thermosetting resin contains a low-shrinking agent and a polymerizable monomer described later for convenience. As the thermosetting resin contained in the thermosetting resin composition for in-mold coating molding in the present invention, a double bond is cleaved and added using a thermally decomposable radical catalyst to form a three-dimensional network structure. An unsaturated polyester resin having a reactive double bond in the molecule, a vinyl ester (epoxy acrylate) resin, a urethane acrylate resin or the like is used. The thermosetting resin may be used alone or in combination of two or more.

The above-mentioned unsaturated polyester resin is usually produced by a known and commonly used method, usually an organic polyol, an aliphatic unsaturated polycarboxylic acid and, if necessary, an aliphatic saturated polycarboxylic acid and / or an aromatic polycarboxylic acid. Manufactured from

On the other hand, the vinyl ester resin is also generally produced by a known and commonly used method from an epoxy resin and a monocarboxylic acid having a reactive double bond such as (meth) acrylic acid.

Further, the urethane acrylate resin is
Usually, it is produced by reacting an organic polyol such as an alkylene diol, an alkylene diol ester, an alkylene diol ether, a polyether polyol or a polyester polyol with an organic polyisocyanate and further reacting with a hydroxyalkyl (meth) acrylate. It is also possible to leave a free isocyanate group at a part of the terminal and combine this with the vinyl ester resin for use.

Examples of the organic polyol used for producing the unsaturated polyester resin include diols, triols, tetrols and mixtures thereof.
It is mainly divided into aliphatic polyols and aromatic polyols. Of these, typical examples of the aliphatic polyol include ethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, triethylene glycol, neopentyl glycol, dibromoneopentyl glycol, hexamethylene glycol, trimethylene glycol, and trimethylol. There are propane, glycerin, pentaerythritol diallyl ether, hydrogenated bisphenol A and the like.

As a typical aromatic polyol, bisphenol A or bisphenol S or an oxirane compound such as ethylene oxide, propylene oxide or butylene oxide is added to these bisphenol A or bisphenol S on average in one molecule. Examples include polyoxyalkylene bisphenol A and polyoxyalkylene bisphenol S obtained by adding 1 to 20 compounds.

Further, as the aliphatic unsaturated polycarboxylic acid used for producing the unsaturated polyester resin,
(Anhydrous) maleic acid, fumaric acid, (anhydrous) itaconic acid and the like, and as the aliphatic saturated polycarboxylic acid, sebacic acid, adipic acid, (anhydrous) succinic acid and the like, the aromatic polycarboxylic acid Examples thereof include (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride and the like.

As the epoxy resin used for producing the vinyl ester resin, epichlorohydrin and bisphenol A are also prepared by a known method.
A bisphenol A type epoxy resin produced from, epichlorohydrin and a brominated bisphenol A type epoxy resin produced from brominated bisphenol A, a novolak type epoxy resin produced by glycidyl etherification of phenol novolac or orthocresol novolak, and various amines Tetraglycidyl metaxylenediamine, tetraglycidyl 1,3-bisaminomethylcyclohexane, tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m obtained by reacting epichlorohydrin
-Aminophenol, diglycidyl aniline, glycidyl amine compounds such as diglycidyl orthotoluidine, and the like.

Examples of the organic polyol used for producing the urethane acrylate resin include alkylene diols such as ethylene glycol, propylene glycol, diethylene glycol, diisopropylene glycol, polyethylene glycol, polypropylene glycol, butane diol, and other hydroxyalkyl ethers. Examples of the polyether polyol include polyoxymethylene, polyethylene oxide, polypropylene oxide and the like, and examples of the polyester polyol include the above-mentioned organic polyols and polyester polyols having hydroxyl groups at both ends, which are produced by polycarboxylic acid.

As the organic polyisocyanate used for producing the urethane acrylate resin, tolylene diisocyanate, isophorone diisocyanate,
Examples thereof include polymethylene polyphenyl diisocyanate.

Examples of the hydroxyalkyl (meth) acrylate used for producing the urethane acrylate resin include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and the like. The group is usually attached to the beta carbon of the alkyl group. Alkyl groups can usually contain up to 8 carbon atoms.

In the thermosetting resin composition for in-mold coating of the present invention, polyvinyl acetate, polymethyl (meth) acrylate, polyethylene, ethylene vinyl acetate copolymer, vinyl acetate-styrene copolymer is used as a low shrinking agent. Thermoplastic resins such as polymers, polybutadiene, saturated polyesters, saturated polyethers and the like can be used in appropriate amounts as needed.

Furthermore, an appropriate amount of an inorganic filler can be added to the thermosetting resin composition for in-mold coating molding of the present invention depending on the purpose and application. Examples of usable inorganic fillers include the following.

That is, elemental minerals such as sulfur, graphite and diamond, sulfide minerals such as pyrite, halogenated minerals such as rock salt and potassium rock salt, carbonate minerals such as carbon calcium, phosphate minerals such as cyanite and carnotite. Etc., vanadate minerals, barite (barium sulfate), gypsum (calcium sulfate) and other sulfate minerals, borax and other borate minerals, perovskite and other titanate minerals, mica, talc (talc) , Silicate minerals such as pyrophyllite, kaolin, quartz, feldspar, metal oxides such as titanium oxide, corundum (aluminum oxide), aluminum hydroxide, glass products such as (hollow) glass spheres And natural or artificial minerals, processed or purified or processed products thereof, and mixtures thereof.

The filler is preferably added in an amount of 0 to 300 parts by weight based on 100 parts by weight of the thermosetting resin. If the amount added exceeds 300 parts by weight, it becomes difficult to uniformly disperse the filler in the resin and the monomer, and since the viscosity becomes high, the flow in the mold becomes poor and it becomes difficult to obtain dimensional stability. Tend.

Further, in the thermosetting resin composition for in-mold coating molding of the present invention, various reinforcing fibers, that is, glass fiber, carbon fiber, etc. can be added as a reinforcing material in an appropriate amount, if necessary.

Further, in the thermosetting resin composition for in-mold coating of the present invention, if necessary, styrene, α-methylstyrene, divinylbenzene, vinyltoluene, diallylphthalate, various acrylate monomers, various methacrylates. An appropriate amount of a polymerizable monomer such as a monomer can be added.

Known polymerization initiators such as ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, alkyl peresters, percarbonates and peroxyketals, dimethylaniline and naphthene. Known curing accelerators such as cobalt acid, polymerization inhibitors such as parabenzoquinone, carbon black and titanium oxide, iron oxide, cyanine pigments, aluminum flakes, nickel powder, pigments such as gold powder and silver powder, azo dyes and anthraquinone pigments , Indigoid,
A suitable amount of a stilbene-based dye, a conductivity-imparting agent such as carbon black, an emulsifier, a metal soap such as zinc stearate, an aliphatic phosphate, a release agent such as lecithin, etc. may be added depending on the application and purpose. it can.

The coating layer forming composition used in combination with the in-mold thermosetting resin composition of the present invention is a thermosetting unsaturated polyester resin, vinyl ester resin, urethane acrylate resin or the like. Resin is used, and various fillers, additives and the like can be added if necessary.

The thermosetting resin composition for in-mold coating molding of the present invention obtained as described above is a thermosetting resin composition for in-mold coating molding having the form of SMC or BMC by a conventionally known method. And can be used as a conventionally known in-mold coating together with the coating layer forming composition.

For example, SMC is put in a molding die heated to 130 to 160 ° C., pressure molding is carried out at a pressure of 40 to 120 kg / cm ² for 30 seconds to 5 minutes, and then the mold is slightly opened for coating. Injecting the layer-forming composition, then 5 to 120
By reheating and repressurizing at 130 to 160 ° C. for 30 seconds to 5 minutes at 130 kg / cm ² , the composition for forming a coating layer is spread over the entire surface of the molded SMC and cured to form a coating layer. be able to.

Further, as disclosed in Japanese Patent Laid-Open No. 61-273921, SMC at 130 to 160 ° C., 40 to 1
Coating layer forming composition at a high pressure of 100 to 300 / cm ² using a high pressure injection machine in a state where the pressure was reduced to 10 to 30 kg / cm ² after several tens of seconds to several minutes pressed at 20 kg / cm ² Is injected into the mold and again 30 to 100 kg / c
There is also a method of increasing the pressure to m ² to spread and harden the coating layer forming composition. When the thermosetting resin composition for in-mold coating molding of the present invention is used in the in-mold coating method as described above, a coated molded article having good adhesion can be easily molded.

[0036]

The thermosetting resin composition for in-mold coating molding of the present invention is pressure-molded when a compound having an ethylenic double bond and --NH ₂ group in the molecule is contained in the resin component. At times, the vinyl group undergoes a copolymerization reaction with a thermosetting resin or the like, and as a result, an amino group or a carbamoyl group is formed on the surface of the thermosetting resin. The amino group or the carbamoyl group causes polarization between hydrogen and nitrogen, which increases the polarity of the surface of the thermosetting resin. Therefore, in the composition for forming a base material and a coating layer using the thermosetting resin, Hydrogen bonds with the resin are increased, which enhances the adhesion between the base material and the coating layer.

The thermosetting resin composition for in-mold coating of the present invention is added when a compound having an ethylenic double bond, a hydroxyl group and a --NH-- group in the molecule is contained in the resin component. During pressure molding, the ethylenic double bond undergoes a copolymerization reaction with a thermosetting resin or the like, and as a result, a hydroxyl group and a -NH- group are formed on the surface of the thermosetting resin. Since the hydroxyl group and the --NH-- group electrically polarize to increase the polarity of the surface of the thermosetting resin, the base material using this thermosetting resin and the resin in the coating layer forming composition Hydrogen bonds between the two are increased, which enhances the adhesion between the substrate and the coating layer.

The coated molded article of the present invention is a compound having an ethylenic double bond and --NH ₂ group in the molecule for a substrate,
Alternatively, since a curable resin composition for in-mold coating molding in which a compound having an ethylenic double bond, a hydroxyl group and a --NH-- group in the molecule is contained in the resin component is used, the coating layer is firmly formed on the substrate. It is closely attached.

[0039]

Example 1 The following compositions were mixed and sufficiently stirred, and then glass fiber (Roving made by Asahi Fiber Glass Co., Ltd., trade name: “ER4630LBD166W” with a length of 2 was mixed with an SMC impregnating device.
It was impregnated with 60 parts by weight (cut into 5 mm) to obtain SMC as a thermosetting resin composition.

Composition Polyester resin A (containing about 60% by weight of isophthalic acid-based unsaturated polyester resin and about 40% by weight of styrene monomer): 70 parts by weight Polystyrene resin B (about 30% by weight of polystyrene resin and about 70% by weight of styrene monomer) %) Methacrylamide (manufactured by Wako Pure Chemical Industries, Ltd.) 5 parts by weight Calcium carbonate powder (manufactured by Nitto Koka Co., Ltd.) 120 parts by weight Curing agent (containing t-butylperoxybenzoate) Rate 98
%) ...... 1 part by weight Thickener (magnesium oxide powder) ...... 1 part by weight Next, 100 parts by weight of polyester resin A, 100 parts by weight of calcium carbonate and 1 part by weight of a curing agent (t-butylperoxybenzoate). After mixing and stirring sufficiently, a resin composition for in-mold coating was obtained.

Using the SMC and the coating layer-forming composition prepared as described above, molding was carried out in the following manner.
First, the upper mold and the lower mold were heated to 150 ° C., 30 cm
About 700 g of the above SMC was charged in a square flat plate-shaped mold of × 30 cm (the charged SMC had a thickness of about 4 mm). Next, 100 kg / cm
After pressure molding at a pressure of ² for 100 seconds, the mold is slightly opened, 10 ml of the above composition for coating in the mold is injected, the mold is closed again, and reheating and repressurizing at 80 kg / cm ² for 120 seconds. As a result, the composition for in-mold coating was spread over the entire surface of the molded SMC and cured to form a coating layer.
After that, the mold is opened and demolded, and the surface is 100 μm thick.
A molded article coated with the coating layer of was obtained.

On the surface of the molded article obtained as described above on which the coating layer is formed, a straight line reaching the substrate of the molded article (a base material made of a thermosetting resin) is used with a cutter knife with an interval of 2 mm. 11 pieces were drawn in parallel with each other, and then 11 lines which were orthogonal to the straight line were drawn in the same manner to form a grid-like portion. Further, an adhesive tape (manufactured by Sekisui Chemical Co., Ltd., trade name: Sekisui Tape) was attached to the cross-shaped portion, and then the number of remaining squares of the cross was checked by peeling it off (hereinafter, referred to as a cross-contact test. I call it). As a result, the ratio of the masses in which the coating layer remained was 100/100. That is, in the cross-cut adhesion test, peeling of the coating layer was not recognized.

Example 2 An SMC was obtained in the same manner as in Example 1 except that 10 parts by weight of acrylamide (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of methacrylamide.

When a coated molded product was obtained in the same manner as in Example 1 and a cross-cut adhesion test was performed and evaluated, the number of remaining masses in which the coating layer was not peeled off was 100/100. Example 3 An SMC was obtained in the same manner as in Example 1 except that 3 parts by weight of allylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of methacrylamide.

Further, when a coated molded product was obtained in the same manner as in Example 1 and a cross-cut adhesion test was conducted and evaluated, the number of remaining masses in which the coating layer was not peeled off was 100/100. Example 4 An SMC was obtained in the same manner as in Example 1 except that 5 parts by weight of N-methylol methacrylamide (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of methacrylamide.

Further, when a coated molded product was obtained in the same manner as in Example 1 and a cross-cut adhesion test was conducted and evaluated, the number of remaining masses in which the coating layer was not peeled off was 100/100. Comparative Example 1 Example 1 except that no methacrylamide was used.
SMC was obtained in the same manner as.

Further, when a coated molded product was obtained in the same manner as in Example 1 and a cross-cut adhesion test was performed and evaluated, the number of remaining masses in which the coating layer was not peeled off was 31/100. The mixing ratios of the thermosetting resin compositions of Examples 1 to 3 and Comparative Example 1 and the results of the cross-cut adhesion test are summarized in Table 1 below.

[0048]

[Table 1]

Description of Examples 1 to 4 and Comparative Example 1 above,
As is clear from Table 1 and Table 1, selected from compounds having an ethylenic double bond and an --NH ₂ group in the molecule, and compounds having an ethylenic double bond, a hydroxyl group and an --NH-- group in the molecule In Comparative Example 1 which does not contain at least one compound described above, the adhesion of the coating layer is considerably low, while in Examples 1 to 4, the coating layer was completely peeled off in the cross-cut adhesion test. It was found that the coating layer was firmly adhered to the thermosetting resin.

[0050]

EFFECTS OF THE INVENTION Since the thermosetting resin composition for in-mold coating of the present invention has the above-mentioned constitution, the vinyl group causes a copolymerization reaction with the thermosetting resin or the like during pressure molding, Amino groups or carbamoyl groups, or hydroxyl groups and --NH-- groups are formed on the surface, and hydrogen bonds between the base material using the thermosetting resin and the resin in the coating layer forming composition increase, The adhesiveness between the base material and the coating layer is increased, and the adhesiveness between the coating layer and the molded product base material made of a thermosetting resin is effectively enhanced.

Since the coated molded article of the present invention is constructed as described above, it is a molded article with a coating layer in which the coating layer is firmly adhered to the base material.

Claims (2)

[Claims] 1. A thermosetting resin composition used for forming a base material for in-mold coating molding for forming a coating layer on a base material in a molding die, the resin component containing the thermosetting resin. A compound having an ethylenic double bond and --NH ₂ group in the molecule, and an ethylenic double bond, a hydroxyl group and --NH
A thermosetting resin composition for in-mold coating molding, containing at least one compound selected from compounds having a group in the molecule. 2. A coated molded article having a coating layer formed on a base material, wherein the thermosetting resin composition for in-mold coating molding according to claim 1 is used for a base material. ..