JPH07242715A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To provide a low-shrinkage thermosetting resin compsn. excellent in transparency and water resistance. CONSTITUTION:A low-shrinkage thermosetting resin compsn. comprises 100 pts.wt. thermosetting resin compsn. comprising a thermosetting resin and a polymerizable monomer, and 0.1-50 pts.wt. cross-linked polymer particles having an average particle diameter of 0.01 to 3mum and prepd. by polymerizing a monomer contg. at least 10wt.% cross-linkable monomer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermosetting resin composition, and more particularly to a thermosetting resin composition having excellent transparency and water resistance.

2. Description of the Related Art Generally, a thermosetting resin is used as a raw material for fiber reinforced plastic (FRP) or as an aggregate by a sheet molding compound (SMC) molding method or a bulk molding compound (BMC) molding method. It is used in a wide range of fields such as resin concrete and resin mortar. However, since the thermosetting resin has a large curing shrinkage ratio of 5 to 10%, cracks, warps, dents and the like occur in the obtained molded product, and a smooth and transparent molded product cannot be obtained.
Therefore, conventionally, thermoplastic resin particles such as polystyrene, polymethylmethacrylate or copolymers thereof have been added as a shrinkage reducing agent.

However, when the thermoplastic resin particles are used as a shrinkage reducing agent, fine cracks are generated due to the remarkable thermal expansion of the thermoplastic resin particles, so that light is generated at the interface between the matrix and the fine cracks. Scattering occurs, resulting in the problem that only molded articles having poor transparency can be obtained. In addition, in molded products such as bathtubs and vanities used in contact with water, water penetrates into minute cracks, causing whitening and discoloration of the molded products, resulting in poor water resistance and durability. There was a problem of decline.
The present invention is to provide a low-shrinkage thermosetting composition which is particularly excellent in transparency and water resistance.

[0002]

The present invention comprises 10 parts by weight of 100 parts by weight of a thermosetting resin composition (C) comprising a thermosetting resin (A) and a polymerizable monomer (B). % Of the crosslinked polymer particles (D) having an average particle diameter of 0.01 to 3 μm, which is obtained by polymerizing the monomer (b) containing at least 10% of the crosslinkable monomer (a). Provided is a thermosetting resin composition characterized by containing parts by weight.

In the present invention, the thermosetting resin (A) is a resin which has a polymerizable unsaturated group in the molecule and undergoes radical polymerization with a polymerizable monomer, and examples thereof include unsaturated polyester resin and vinyl ester resin. And the like. As the polymerizable monomer (B) of the present invention, one kind or a combination of two or more kinds of radically polymerizable polymerizable monomers can be used, and an aromatic vinyl compound such as styrene, α-methylstyrene and divinylbenzene. Ethylenically unsaturated ester compounds such as methyl methacrylate and diallyl phthalate. The mixing ratio of the thermosetting resin (A) and the polymerizable monomer (B) is not particularly limited, but the weight ratio of the thermosetting resin (A) and the polymerizable monomer (B) is preferably ( A) / (B) = 10/90 to 99/1, and more preferably (A) / (B) = 30/70 to 99/1. The average particle diameter of the crosslinked polymer particles (D) is 0.
It is 01 to 3 μm, preferably 0.05 to 2 μm. If the average particle size is less than 0.01 μm, the dimensional stability of the molded product is poor, and if it exceeds 3 μm, the transparency of the molded product is reduced. The crosslinked polymer particles (D) or the modified crosslinked polymer particles (E) are 0.1 to 50 parts by weight, preferably 0.1 to 3 parts by weight, relative to 100 parts by weight of the thermosetting resin composition (C).
Contains 0 parts by weight. If it is less than 0.1 parts by weight, molding shrinkage is high, and if it exceeds 50 parts by weight, the performance of the thermosetting resin is not good, which is not preferable. The crosslinked polymer particles (D) are obtained by polymerizing the monomer (b) containing 20% by weight or more of the crosslinkable monomer (a). The crosslinkable monomer (a) is a monomer having two or more groups having a polymerizable double bond in the molecule.

Examples of the crosslinkable monomer (a) include divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate and neopentyl glycol dimethacrylate. , Methylenebisacrylamide, and divinylbenzene and ethylene glycol dimethacrylate are particularly preferable. You may use these in combination of 2 or more types. The content of the crosslinkable monomer (a) in the monomer (b) used in the crosslinked polymer particles (D) is 20 to 100% by weight, preferably 3
It is 0 to 100% by weight. If the amount of the crosslinkable monomer (a) is less than 20% by weight, the degree of crosslinking is low, and fine cracks are generated in the crosslinked polymer particles (D), resulting in a molded product having poor transparency. Monomer (b) other than crosslinkable monomer (a)
As, for example, styrene, ethyl vinyl benzene,
Aromatic monovinyl compounds such as α-methylstyrene, fluorostyrene, vinylpyridine, acrylonitrile,
Vinyl cyanide compounds such as methacrylonitrile, butyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, acrylic acid ester monomers such as N, N'-dimethylaminoethyl acrylate, butyl methacrylate, 2 -Ethylhexyl methacrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, N,
Methacrylic acid ester monomers such as N'-dimethylaminoethylmethacrylate, acid anhydrides of mono- or dicarboxylic acids and dicarboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, acrylamide,
Methacrylamide, N-methylolacrylamide, N
An amide-based monomer such as methylolmethacrylamide, an ionic monomer such as sodium styrenesulfonate and sulfonated isoprene can be used. Further, within a range allowable in terms of polymerization rate and polymerization stability, conjugated double bond compounds such as butadiene and isoprene, vinyl ester compounds such as vinyl acetate, 4-methyl-1-pentene and other α-olefins. Compounds can also be used.

The modified crosslinked polymer particles (E) of the present invention are
A polymer composed of the monomer (C) containing less than 20% by weight, and more preferably 5% by weight or less of the crosslinkable monomer (a) on the surface of the above crosslinked polymer (D) is used.
Preferably 0.1 to 100 parts by weight per 100 parts by weight,
More preferably, it is laminated in an amount of 0.1 to 30 parts by weight. As the crosslinkable monomer (a), those shown above can be used. Further, as the monomer (D) copolymerized with the monomer (a), those shown above can be used. Examples of the monomer (C) include aromatic vinyl compounds such as styrene and ethylvinylbenzene, carboxylic acid compounds such as (meth) acrylic acid, and butyl (meth) acrylate,
A combination of two or more kinds of (meth) acrylic acid ester compounds such as methyl (meth) acrylate is preferable. When the modified crosslinked polymer particles (E) are used, the dispersibility is excellent in the composition, and as a result, the effect intended by the present invention is further excellent.

A preferred method for producing the crosslinked polymer particles (D) of the present invention is a method of polymerizing the monomer (b) by the emulsion polymerization method. Further, as a preferred method for producing the modified crosslinked polymer particles (E) of the present invention, the following method for obtaining the crosslinked polymer particles (D) to the modified crosslinked polymer particles (E) in the same reaction system, and crosslinking The following method may be mentioned, in which the polymer particles (D) are separately polymerized and the modified crosslinked polymer particles (E) are obtained by using them. : Cross-linked polymer particles (D) obtained by polymerizing the monomer (b)
To obtain the modified crosslinked polymer particles (E) of the present invention in the first step of obtaining Method. First
The polymerization conversion rate in the step is preferably 70% by weight or more, more preferably 90% by weight or more. The unreacted monomer (b) in the first step is added to the monomer (C) in the second step and treated as the monomer (C). : A method of polymerizing the monomer (b) to separately produce crosslinked polymer particles (D), and polymerizing the monomer (C) in the presence of the (D). In most of the modified crosslinked polymer particles (E) of the present invention obtained by the above method, the polymer of the monomer (C) is partially or entirely laminated on the surface of the crosslinked polymer particles (D). Although it has a structure, a part of the polymer particles of the crosslinked polymer particles (D) and the monomer (C) coexist. The content of particles having a structure in which the above polymer is partially or entirely laminated is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, most preferably 98% by weight. That is all. The method for polymerizing the above-mentioned monomer is not particularly limited, but is preferably an emulsion polymerization method, a dispersion polymerization method, a suspension polymerization method, and more preferably an emulsion polymerization method.

In the emulsion polymerization method of the above-mentioned crosslinked polymer particles (D) and modified crosslinked polymer particles (E), an emulsifier may not be used in some cases, but the emulsifier to be used is one used in ordinary emulsion polymerization. Examples of the anionic surfactants include sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium dialkyl sulfosuccinate, formalin condensate of naphthalene sulfonic acid, and polyoxyethylene alkylphenyl ether sulfate ammonium salt. Examples thereof include nonionic surfactants such as polyoxyethylene nonyl phenyl ether, polyethylene glycol monostearate, sorbitan monostearate. Furthermore, commercially available emulsifiers New Frontier A-229E, N177E, Aqualon RN-20, HS-10 [Daiichi Kogyo Seiyaku Co., Ltd.]
Manufactured], Eleminor JS-2, RS-30 [manufactured by Sanyo Kasei Co., Ltd.], Latemur S-120A, S-180.
For example, [manufactured by Kao Corporation] can be used. One kind of these emulsifiers may be used, but if two or more kinds are used in combination, it is more effective in terms of stability. A more preferable combination is a combination of an anionic surfactant and a nonionic surfactant. If necessary, a water-soluble polymer such as polyvinyl alcohol, polyvinylpyrrolidone or hydroxypropylcellulose may be used as a stabilizer. The polymerization initiator to be used is not particularly limited as long as it is used in ordinary emulsion polymerization and dispersion polymerization, but potassium persulfate, sodium persulfate, persulfate initiators such as ammonium persulfate, and azo. The system initiator and hydrogen peroxide, organic peroxide and the like may be used alone or in combination with various reducing agents such as ascorbic acid. Then, examples of the method for adding the monomer include a method in which the monomer is added all at once to the reaction vessel to perform polymerization, a method in which the monomer is continuously or intermittently continuously added, and the like. Particularly in the polymerization of the crosslinked polymer particles (D), a so-called seed polymerization method in which the polymerization is performed in the presence of seed particles such as polystyrene particles can be adopted.

The curable resin composition of the present invention comprises a thermosetting resin (A), a polymerizable monomer (B) and a crosslinked polymer particle (D) or a modified crosslinked polymer particle (E), and if necessary. A curing agent, a polymerization inhibitor, a filler, a thickener, an internal release agent, and other additives may be contained. As the curing agent, organic peroxides such as benzoyl peroxide and parachlorobenzoyl peroxide are used alone or in combination of two or more. As the polymerization inhibitor, p
-Quinones such as benzoquinone and hydroquinones such as pt-butylcatechol are used. Examples of the filler include calcium carbonate, clay, aluminum hydroxide, talc, mica, glass fiber and the like. As the thickener, magnesium oxide, magnesium hydroxide or the like is used. As the internal mold release agent, a metallic soap such as zinc stearate or a phosphoric acid ester type is used.
The thermosetting resin composition of the present invention is a bathtub or vanity,
It is suitable for producing marble-like molded products such as kitchen counters where transparency is important.

[0009]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. In the following description, "part" means part by weight and% means% by weight. [Measurement Method of Particle Diameter] The average particle diameter of the crosslinked polymer particles was measured by directly obtaining the average value of the particle diameters measured for 100 particles by a transmission electron micrograph. Production Example 1 10 parts of polystyrene particles having a weight average molecular weight of 15,000 and an average particle size of 0.25 μm, sodium dodecylbenzenesulfonate 5 parts, and divinylbenzene 10
0 parts, 1 part of sodium persulfate, and 700 parts of ion-exchanged water were charged into a reaction vessel, and while stirring while blowing nitrogen gas,
Polymerization was carried out at 80 ° C. for 1 hour to produce crosslinked polymer particles (1). Note that divinylbenzene is a commercial product and has a purity of 81
%, The remaining 18% is ethyl vinylbenzene, the remaining 1%
Used an impurity. The average particle size of the obtained crosslinked polymer particles (1) was measured to be 0.5 μm.
Met. Production Example 2 In the first step, 10 polystyrene particles having a weight average molecular weight of 15,000 and an average particle diameter of 0.25 μm were used.
, 5 parts of sodium dodecylbenzene sulfonate, 50 parts of divinylbenzene, 50 parts of styrene, 1 part of sodium persulfate, and 700 parts of deionized water are charged into a reaction vessel, and polymerization is carried out at 80 ° C. for 1 hour under stirring while blowing nitrogen gas. did. Then, 50 parts by weight of styrene in the second step,
50 parts of methyl methacrylate was added as a mixed monomer and 0.5 part of sodium persulfate was added, and the mixture was polymerized at 80 ° C. for 3 hours to complete the polymerization, to produce crosslinked polymer particles (2).
The same divinylbenzene as that used in Production Example 1 was used. Obtained crosslinked polymer particles (2)
The average particle diameter of was measured to be 0.6 μm. Production Example 3 10 parts of polystyrene particles having a weight-average molecular weight of 15,000 and an average particle size of 0.25 μm, sodium dodecylbenzenesulfonate 5 parts, and divinylbenzene 5
Parts, 95 parts of styrene, 1 part of sodium persulfate, and 700 parts of ion-exchanged water were charged into a reaction vessel, and polymerized at 80 ° C. for 1 hour under stirring while blowing nitrogen gas to produce crosslinked polymer particles (3). The same divinylbenzene as that used in Production Example 1 was used. When the average particle diameter of the obtained crosslinked polymer particles (3) was measured,
It was 0.5 μm. Production Example 4 50 parts of divinylbenzene, 50 parts of styrene, 5 parts of sodium dodecylbenzenesulfonate, 0.5 part of polyvinyl alcohol, 1000 parts of ion-exchanged water, 1 part of α, α′-azoisobutyronitrile were charged into a reaction vessel. Then, the mixture was stirred at 12000 rpm for 60 minutes using a homomixer to make it uniform. Then, heat to 80 ° C while blowing nitrogen gas,
Stirring was continued for 3 hours to carry out suspension polymerization to produce crosslinked polymer particles (4). The same divinylbenzene as that used in Production Example 1 was used. When the average particle diameter of the obtained crosslinked polymer particles (4) was measured, it was 1
It was 0.0 μm. Table 1 shows the composition and average particle size of the obtained crosslinked polymer particles.

[0010]

[Table 1]

Example 1 A thermosetting resin, a polymerizable monomer, and water, which was a dispersion medium of the crosslinked polymer particles obtained in Production Example 1, were dried and removed, and a sheet molding compound having the following composition was used. It was adjusted. Unsaturated polyester resin (Brand name Esther RT-400, manufactured by Mitsui Toatsu Chemicals, Inc.) 65 parts Styrene (monomer) 35 parts Crosslinked polymer particles (1) 25 parts Glass fiber (13 mm chopped strand) 70 parts Calcium carbonate 150 parts Benzoyl peroxide 1 part Zinc stearate 6 parts Magnesium oxide 1 part These sheet molding compounds are 2 at 40 ° C.
After thickening for 4 hours, press forming (pressure 100 kg / c
m ^2, temperature 140 ° C., subjected to time 5 minutes) 20 × 20c
A molded product (a) having a thickness of m and a thickness of 4 mm was obtained. Molding shrinkage, water resistance, and transparency of the obtained molded article (A) were evaluated by the methods described below, and the results are shown in Table 2. Molding shrinkage rate: Based on JIS-K-6911, a disk having a diameter of 90 mm and a thickness of 11 mm was separately press-formed to obtain the molding shrinkage rate. Transparency: A piece of 50 x 50 mm and a thickness of 4 mm is cut out from the molded product, placed as a test piece on the white portion of the concealment rate test paper of the Japan Paint Inspection Association, and the color difference meter ( Minolta CR-200 type) with L _w ,
a _w and b _w were measured. Next, the test piece was transferred to the black part, and L _b , a _w , and b _w were measured in the same manner. The two color differences ΔE were calculated by the following formula, and the transparency was determined.
Here, ΔE means that the larger this value is, the higher the transparency is. ΔE = ^{_{[(L w -L b) 2 +}} (a w -a b) 2 + (b w
-B _b) ^{2] 1/2} Water resistance moldings than 50 × 50 mm, cut out a plate piece having a thickness of 4 mm, which in hot water at 50 ° C. as a test piece 144
A continuous immersion test was conducted for a time. Before the test and after the test 2
The color difference ΔE was determined in the same manner as in the transparency test for the test piece that had been left at room temperature for 4 hours, the rate of change in ΔE before and after the test was determined, and the water resistance was determined based on the degree of transparency deterioration. Change rate of ΔE = (ΔE before hot water test−Δ after hot water test
E) / ΔE × 100 before warm water test Example 2 A molded article (a) was obtained by the same method except that the crosslinked polymer particles (2) were used in place of the crosslinked polymer particles (1) in Example 1. . Molding shrinkage, water resistance, and transparency of the obtained molded product (a) were evaluated by the methods described below, and the results are shown in Table 2. Comparative Example 1 A molded article (C) was obtained in the same manner as in Example 1 except that the crosslinked polymer particles (3) were used instead of the crosslinked polymer particles (1). Molding shrinkage, water resistance, and transparency of the obtained molded product (C) were evaluated by the methods described below, and the results are shown in Table 2. Comparative Example 2 A molded article (D) was obtained in the same manner as in Example 1, except that the crosslinked polymer particles (4) were used instead of the crosslinked polymer particles (1). Molding shrinkage, water resistance, and transparency of the obtained molded article (D) were evaluated by the methods described below, and the results are shown in Table 2.

[0012]

[Table 2]

[0013]

EFFECTS OF THE INVENTION In the case of a molded article using a conventional shrinkage reducing agent, the transparency is low and the water resistance is poor, but the crosslinked polymer particles or modified crosslinked polymer particles of the present invention have a low shrinkage. The molded product used as an agent has high transparency and excellent water resistance.

Claims (2)

[Claims] 1. A cross-linking monomer of 10% by weight or more based on 100 parts by weight of a thermosetting resin composition (C) comprising a thermosetting resin (A) and a polymerizable monomer (B). The cross-linked polymer particles (D) obtained by polymerizing the monomer (b) containing (a) and having an average particle diameter of 0.01 to 3 μm are added in an amount of 0.
A thermosetting resin composition containing 1 to 50 parts by weight. 2. The crosslinked polymer particles (D) according to claim 1, relative to 100 parts by weight of the thermosetting resin composition (C) comprising the thermosetting resin (A) and the polymerizable monomer (B). 0.1) to 100 parts by weight of a polymer comprising a monomer (C) containing less than 10% by weight of a crosslinkable monomer (a) per 100 parts by weight of (D). A thermoplastic resin composition comprising 0.1 to 50 parts by weight of modified crosslinked polymer particles (E).