JP2007177126A - Thermosetting molding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting molding material free from styrene, and providing a molded article having characteristics equal to or more than those of a conventional material using the styrene. <P>SOLUTION: The thermosetting molding material contains (A) an unsaturated polyester resin, (B) a reactive diluent, (C) a shrinkage-reducing agent, (D) an inorganic filler and (E) a curing agent, and is free from styrene. The reactive diluent of the component (B) is at least one kind selected from the group consisting of a di(meth)acrylate derivative of an alkylene oxide, and a di(meth)acrylate derivative of a polyalkylene oxide, and the shrinkage-reducing agent of the component (C) is a thermoplastic resin having ≤5,000 number average molecular weight (Mn). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a so-called styrene-free thermosetting molding material that does not use styrene as a reactive diluent.

  Molding materials that contain unsaturated polyester resin as the main component and styrene as a reactive diluent and a fibrous reinforcing material such as glass fiber are easy to handle, fluid, and curable. In addition to being excellent in mechanical strength, heat resistance, water resistance, chemical resistance, etc. of molded products, it is not only residential building materials such as bathtubs, septic tanks and panels, but also parts such as ships and automobiles, general household and Widely used in various fields such as electrical and electronic parts used in industrial electrical equipment.

  However, in the above molding material, styrene contained as a reactive diluent is volatilized by heat at the time of use, giving off a strong irritating odor to the surroundings, and depending on applications, there is a problem of adversely affecting surrounding parts. .

Therefore, it has been studied to suppress the volatilization of styrene, and a molding material has been developed to reduce the amount of residual styrene in the molded product by specifying the blending amount of styrene and using a specific curing agent. (For example, refer to Patent Document 1).
JP 2002-88130 A

  However, this molding material also uses styrene, which is insufficient as a countermeasure for the above problem. Recently, with the enforcement of the Chemical Substances Management Promotion Law (PRTR Law), it has become necessary to notify the amount of emission and transfer when using styrene. From the viewpoint of environmental problems, the use of styrene will become increasingly difficult in the future. It is thought that it will become. Under such circumstances, there has been a strong demand for a thermosetting molding material capable of obtaining a molded product having characteristics equivalent to or higher than those of conventional ones without using styrene at all.

  The present invention has been made to meet such demands, and an object of the present invention is to provide a thermosetting molding material that can obtain a molded product that is styrene-free and that has the same or better properties than conventional ones. To do.

As a result of intensive studies to achieve the above-mentioned object, the present inventors, as a reactive diluent, replaced with styrene as a di (meth) acrylate derivative of alkylene oxide or di (meth) acrylate of polyalkylene oxide. By using a derivative and using a thermoplastic resin with a number average molecular weight in a specific range as a low shrinkage agent, it is styrene-free and has a molding shrinkage, bending strength, and insulation resistance equivalent to or higher than conventional ones. The present inventors have found that a thermosetting molding material having characteristics such as these can be obtained, and have completed the present invention.

  That is, the thermosetting molding material of the present invention includes (A) an unsaturated polyester resin, (B) a reactive diluent, (C) a low shrinkage agent, (D) an inorganic filler, and (E) a curing agent, A thermosetting molding material substantially free of styrene, wherein the reactive diluent of component (B) comprises a di (meth) acrylate derivative of alkylene oxide and a di (meth) acrylate derivative of polyalkylene oxide. It is at least one selected from the group, and the low shrinkage agent of the component (C) is a thermoplastic resin having a number average molecular weight (Mn) of 5000 or less.

  According to the thermosetting molding material of the present invention, it is possible to obtain a molded product having characteristics equal to or higher than those of conventional ones without using styrene, such as an odor associated with the use of styrene and an adverse effect on peripheral parts. The problem can be solved completely.

  Hereinafter, the present invention will be described in detail.

  The thermosetting molding material of the present invention contains (A) an unsaturated polyester resin, (B) a reactive diluent, (C) a low shrinkage agent, (D) an inorganic filler, and (E) a curing agent.

  The unsaturated polyester resin (A) is obtained by esterifying (a) an acid component containing an α, β-unsaturated dibasic acid and (b) an alcohol component.

  Here, examples of the α, β-unsaturated dibasic acid that is an essential component of the acid component (a) include maleic acid, fumaric acid, itaconic acid, citraconic acid, and acid anhydrides thereof. May be used individually by 1 type, and may be used in combination of 2 or more type. In addition, the acid component optionally used in combination with such an α, β-unsaturated dibasic acid includes phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid. Examples include saturated acids such as acid, hexahydrophthalic anhydride, adipic acid, suberic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, pimelic acid, dimethyl succinic acid, and succinic anhydride. Or two or more types may be used in combination.

(B) As the alcohol component, ethylene glycol, propylene glycol,
Dihydric alcohols such as neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, 1,6-cyclodimethanol, glycerin, trimethylolpropane, tris-2-hydroxyethyl isocyanurate, pentaerythritol, etc. These may be used singly or in combination of two or more thereof.

  Furthermore, as the catalyst used in these esterification reactions, phosphorus-containing compounds such as triphenylphosphine and tributylphosphine, tertiary amines such as N, N-benzyldimethylamine, N, N-dimethylphenylamine and triethylamine, quaternary Examples thereof include quaternary compounds such as ammonium salts, quaternary phosphonium salts, and quaternary pyridinium salts, chlorides such as zinc chloride, aluminum chloride, and tin chloride, and organometallic compounds such as tetrabutyl titanate.

  The blending ratio of the unsaturated polyester resin as the component (A) is preferably 10 to 20% by mass with respect to the entire thermosetting molding material, and if it is out of this range, the mechanical strength of the resulting cured product is descend.

  The reactive diluent of the component (B) used in the present invention is at least one selected from the group consisting of di (meth) acrylate derivatives of alkylene oxide and di (meth) acrylate derivatives of polyalkylene oxide.

Examples of the di (meth) acrylate derivative of alkylene oxide include, for example, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4- Examples include butylene glycol di (meth) acrylate and neopentyl glycol di (meth) acrylate. Examples of the di (meth) acrylate derivative of polyalkylene oxide include polyethylene glycol di (meth) acrylates such as diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetraethylene glycol di (meth) acrylate. , Dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, and the like.

  As the reactive diluent of the component (B), it is particularly preferable to use a poly (alkylene oxide) di (meth) acrylate derivative, and in particular, a polyalkylene oxide diene having a number average molecular weight (Mn) in the range of 190 to 2,000. The use of (meth) acrylate derivatives is preferred. More preferably, the number average molecular weight (Mn) is in the range of 190 to 400. This number average molecular weight (Mn) can be measured by, for example, a gel permeation chromatography (GPC) method.

  It is preferable that the mixture ratio of the reactive diluent of this (B) component is 3-15 mass% with respect to the whole thermosetting molding material. If the blending ratio is less than 3% by mass, the molding material becomes highly viscous, and if it exceeds 15% by mass, the mechanical strength of the resulting cured product decreases.

  The low shrinkage agent of the component (C) used in the present invention is a thermoplastic resin having a number average molecular weight (Mn) of 5000 or less, preferably 3000 or less. By using such a thermoplastic resin together with the component (B), the mechanical strength, particularly the bending strength, of the cured product can be improved.

  Examples of the thermoplastic resin include saturated polyester, polyvinyl acetate, polystyrene, polyethylene, styrene-butadiene copolymer, styrene-methacrylic acid copolymer, polybutadiene, etc., and these may be used alone. Alternatively, two or more kinds may be used in combination. From the viewpoint of reducing molding shrinkage, saturated polyester is particularly preferable.

The blending ratio of the low shrinkage agent of the component (C) is preferably 5 to 15% by mass with respect to the entire thermosetting molding material. If the blending ratio is less than 5% by mass, the effect of addition cannot be sufficiently obtained, and if it exceeds 15% by mass, the moldability is lowered.
In addition, said number average molecular weight (Mn) can be measured by the gel permeation chromatography (GPC) method, for example.

  Examples of the inorganic filler of component (D) used in the present invention include calcium carbonate, aluminum hydroxide, silica, silica sand, dolomite, limestone, gypsum, aluminum fine powder, hollow balloon (glass, shirasu, cement), alumina. , Glass powder, cryolite, zirconium oxide, antimony trioxide, titanium oxide, molybdenum dioxide and the like. These inorganic fillers are selected in consideration of workability, mechanical strength, appearance, economic efficiency, and the like of the obtained molded product, but usually calcium carbonate, aluminum hydroxide, silica and the like are preferably used. An inorganic filler may be used individually by 1 type, and may be used in combination of 2 or more type.

  The blending ratio of the inorganic filler of the component (D) is preferably 60 to 80% by mass with respect to the entire thermosetting molding material. When the blending ratio is less than 60% by mass, the resin component and the inorganic component are easily separated, and when it exceeds 80% by mass, the mechanical strength of the obtained cured product is lowered.

  As the curing agent for component (E), an organic peroxide is usually used. Specific examples thereof include t-butylperoxy-2-ethylhexyl monocarbonate, 1,1-di (t-hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -3,3,5. -Trimethylcyclohexane, t-butylperoxy octoate, benzoyl peroxide, methyl ethyl ketone peroxide, acetylacetone peroxide, t-butylperoxybenzoate, dicumyl peroxide, etc., and these may be used alone Alternatively, two or more kinds may be used in combination. Of these, t-butylperoxy-2-ethylhexyl monocarbonate and 1,1-di (t-hexylperoxy) cyclohexane are preferred as the organic peroxide.

  It is preferable that the compounding quantity of the organic peroxide of this (E) component is 0.2-1.5 mass% with respect to the whole thermosetting molding material. If the blending ratio is less than 0.2% by mass, it takes time to cure, and if it exceeds 1.5% by mass, the pot life is shortened. A more preferable range is 0.3 to 1.0% by mass.

  The thermosetting molding material of the present invention can further contain (F) a reinforcing material. (F) The thermosetting molding material containing a reinforcing material is used for BMC (Bulk Molding Compound), SMC (Sheet Molding Compound), and the like.

  Examples of the reinforcing material include glass fibers, glass cloth, carbon fibers, carbon cloth, vinylon fibers, nylon fibers, aromatic polyamide fibers, and polyester fibers, among which glass fibers are preferable. As this glass fiber, for example, glass roving cut into chopped strands can be used. However, in press molding such as BMC and SMC, generally, the longer the fiber length, the worse the appearance of the molded product (weld). Line) is likely to occur, and it is preferable to use one having an average fiber length of 13 mm or less. More preferably, the average fiber length is in the range of 1.5 to 13 mm.

  The blending ratio of the reinforcing material of component (F) is preferably 4 to 20% by mass with respect to the entire thermosetting molding material. If the blending ratio is less than 2% by mass, the mechanical strength of the molded product is lowered, and if it exceeds 30% by mass, the fluidity of the material during molding is lowered.

  In the thermosetting molding material of the present invention, in addition to the above components, a curing accelerator, a release agent, and a polymerization inhibitor that are generally blended in this type of composition within a range that does not impair the effects of the present invention. Additives such as colorants and anti-settling agents can be blended.

  Examples of the curing accelerator include metal salts of naphthenic acid or octylic acid such as cobalt, zinc, zirconium, manganese, and calcium. N, N-dimethylaniline, N, N-diethylaniline, N, N-dimethyl-p-toluidine, acetylacetone, ethyl acetoacetate and the like can also be used. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of the release agent include aliphatic metal soaps such as zinc stearate and calcium stearate, and these may be used alone or in combination of two or more. The compounding quantity of a mold release agent is the range of 0.5-2 mass% normally with respect to the whole thermosetting molding material.

  Examples of the polymerization inhibitor include quinones such as hydroquinone, methoquinone, p-benzoquinone, methylhydroquinone, trimethylhydroquinone, t-butylhydroquinone, catechol, pt-butylcatechol, and pyrogallol.

  These additives may be used individually by 1 type, and may be used in combination of 2 or more type, respectively.

  Examples of the thermosetting molding material of the present invention include (A) unsaturated polyester resin, (B) reactive diluent, (C) low shrinkage agent, (D) inorganic filler, and (E) curing as described above. Easy mixing by mixing the agent and various components blended as necessary according to the conventional method, followed by kneading with a disperse, kneader, three roll mill, etc., and then degassing under reduced pressure. Can be prepared. In addition, in order to mix each component efficiently, it is preferable to mix a reinforcement material last.

  The thermosetting molding material of the present invention preferably has a molding shrinkage at −25 ° C. measured in accordance with JIS K 6911 of −0.03 to + 0.10%.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Example 1
Unsaturated polyester resin as a resin component (manufactured by Nippon Iupika Co., Ltd., trade name: Iupika 7123), polyalkylene oxide dimethacrylate (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Blemmer PDE-150; number as reactive diluent) Average molecular weight (Mn) 286), saturated polyester resin as a low shrinkage agent (Asahi Denka Kogyo Co., Ltd., trade name: P-200; number average molecular weight (Mn) 2000), average particle size 2.6 μm as an inorganic filler Calcium carbonate (manufactured by Nitto Flour Chemical Co., Ltd., trade name: NS-100) and aluminum hydroxide having an average particle size of 8 μm (trade name: H-32, manufactured by Showa Denko KK), t- as a curing agent Butyl peroxy-2-ethylhexyl monocarbonate (Nippon Yushi Co., Ltd., Perbutyl E) and 1,1-di (t-hexylperoxy) cyclohexa (Nippon Yushi Co., Ltd., Perhexa HC), zinc stearate (Asahi Denka Kogyo Co., Ltd., trade name: CZ-55) as a release agent, glass fiber having an average fiber length of 6 mm as a reinforcing material ( Nippon Sheet Glass Co., Ltd., trade name: RES06-BM5) was used.

  The above components excluding glass fibers were charged into a kneader (kneader) at the blending amount (parts by mass) shown in Table 1, and kneaded for about 20 minutes. Thereafter, glass fiber was added and kneaded for 10 minutes to obtain a thermosetting molding material.

Examples 2 and 3
A thermosetting molding material was produced in the same manner as in Example 1 except that the blending amount of the low-shrinkage saturated polyester resin was changed as shown in Table 1.

Comparative Example 1
Thermosetting in the same manner as in Example 1 except that 4 parts by mass of crosslinked polystyrene (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Modiba M202S) was used as the low shrinkage agent instead of the saturated polyester resin. A moldable molding material was produced.

Comparative Example 2
A thermosetting molding material was produced in the same manner as in Example 3 except that styrene (manufactured by Nippon Iupika Co., Ltd., trade name: SM) was added as a reactive diluent.

  About the thermosetting molding material obtained by said each Example and each comparative example, various characteristics were evaluated by the method shown below.

[Molding Shrinkage] Measured according to JIS K 6911.
[Specific gravity] Measured according to JIS K 6911.
[Bending strength] Measured according to JIS K 6911.
[Fluidity (disc elongation)] About a disc-shaped molded product (5 g) molded by a 37-t compression molding machine under conditions of a clamping pressure (gauge pressure) of about 3.9 MPa and a mold temperature of 165 ° C. ± 3 ° C. The maximum diameter and the minimum diameter were measured, and the average value was calculated.
[Odor] Using a 37t compression molding machine, a disk-shaped test piece (diameter 50 mm, thickness 3 mm) was prepared under conditions of a mold clamping pressure (gauge pressure) of about 3.9 MPa and a mold temperature of 165 ° C. ± 3 ° C. After that, this was put into a 500 ml beaker and sealed, left in a thermostatic bath at 80 ° C. for 30 minutes, cooled at room temperature, and opened, and the odor was determined based on human olfaction (three judges). Moreover, the odor was similarly determined about what gave the annealing treatment (130 degreeC x 1 hour) to the test piece.

These results are also shown in Table 1.

  As is clear from Table 1, the thermosetting molding material of the present invention is equivalent to or more than the conventional molding material using styrene (Comparative Example 1) in terms of molding shrinkage rate, bending strength, and fluidity. In addition, the bending strength is particularly improved as compared with Comparative Example 2 using a conventional low shrinkage agent.

Claims (6)

A thermosetting molding material containing (A) an unsaturated polyester resin, (B) a reactive diluent, (C) a low shrinkage agent, (D) an inorganic filler and (E) a curing agent and substantially free of styrene. Because
The (B) reactive diluent is at least one selected from the group consisting of di (meth) acrylate derivatives of alkylene oxide and di (meth) acrylate derivatives of polyalkylene oxide, and (C) the low shrinkage A thermosetting molding material, wherein the agent is a thermoplastic resin having a number average molecular weight (Mn) of 5000 or less.   The thermosetting molding material according to claim 1, wherein the component (C) is a thermoplastic resin having a number average molecular weight (Mn) of 3000 or less.   The thermosetting molding material according to claim 1, wherein the thermoplastic resin is a saturated polyester resin. The thermosetting molding material according to any one of claims 1 to 3, wherein the component (B) is a di (meth) acrylate derivative of polyalkylene oxide.   The thermosetting molding material according to claim 1, further comprising (F) a reinforcing material.   The thermosetting molding material according to claim 5, wherein a molding shrinkage ratio of the cured product at 25 ° C. is −0.03 to + 0.10%.