JPH1192535A - Unsaturated polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition which can give a molded article excellent in surface gloss and surface smoothness by blending an unsaturated polyester, a monomer copolymerizable therewith, a three-dimensional polystyrene and a specified curing agent. SOLUTION: This composition contains an unsaturated polyester, a monomer copolymerizable therewith, a three-dimensional polystyrene serving as a shrinkage reducing agent, and a curing agent represented by formula I [wherein R<1> is a 5C or higher alkyl; and R<2> is phenyl, substituted phenyl, or -O-R<3> (wherein R<3> is alkyl)]. It is desirable that the unsaturated polyester contains at least 10 mol.% hydrogenated bisphenol A skeleton. When the curing agent represented by formula I comprises one wherein R<2> is phenyl, and R<1> is a group represented by formula II (wherein R<4> is a 2C or higher alkyl), the surface gloss and surface smoothness of a molded article obtained are particularly improved so that a molded article excellent in surface conditions can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unsaturated polyester resin composition used as a molding material in a molded article in which appearance is important, such as a unit-type bathtub.

[0002]

BACKGROUND OF THE INVENTION Unsaturated polyester resins generally include a saturated polybasic acid, an unsaturated polybasic acid, and a polyhydric alcohol.
An unsaturated polyester obtained by polycondensation is dissolved in a polymerizable monomer.

[0003] Such unsaturated polyester resins are liquid resins having a relatively low viscosity, and are cured even at room temperature depending on the use of the catalyst, and at the time of curing, like many other thermosetting resins. Since no gas is produced as a by-product, a large molding pressure is not required in molding. For this reason, the unsaturated polyester resin has been developed as a reinforced plastic resin because it is easy to produce a large-sized molded product having strength by impregnating the unsaturated polyester resin with a reinforcing fiber material such as glass fiber.

As a molding material using such an unsaturated polyester resin, a sheet molding compound (SMC) and a bulk molding compound (BMC) are known. The above SMC and BMC are
For an unsaturated polyester resin, for example, a resin composition obtained by adding a filler, a curing agent, a release agent, a pigment, a thickener, and the like is impregnated into a reinforcing fiber material such as glass fiber, and is formed into a sheet or bulk. It is formed in a shape.

[0005] Such SMC and BMC are mainly used for molded articles obtained by compression molding (press molding). The obtained molded product is used for a wide range of industries such as housing equipment and industrial parts. By the way, in these industrial fields, in particular, in water-related products in housing equipment, in recent years, the texture of appearance such as surface smoothness and gloss has been regarded as important. The above-mentioned water-applied product refers to a product that comes into contact with water on a daily basis, for example, used in bathtubs, kitchens, toilets, and the like.

However, molded articles using the above-mentioned SMC and BMC have a problem that the gloss of the surface of the obtained molded article is reduced due to shrinkage of the unsaturated polyester resin upon cooling after press molding. .

Therefore, conventionally, as a method for improving the gloss of the surface of a molded article, a thermoplastic polymer has been used as a low-shrinking agent at the time of curing in order to smooth the surface of the molded article and to give a glossy feeling. In the press molding, a method from the molding condition side such as setting a temperature difference between the surface to be the front side of the molded product in the mold and the surface to be the back surface to improve the pressure on the surface of the molded product. Has been considered. In addition, it has been found that a slight difference in surface gloss and surface smoothness is caused by variously changing the type of the curing agent and the reactivity of the resin.

[0008] However, if the amount of the thermoplastic polymer as a low-shrinking agent is increased in order to improve the surface smoothness of the surface of the molded article, the thermoplastic polymer emerges (scumming), conversely. The appearance such as the gloss of the surface deteriorates.

Therefore, in order to suppress this scumming, it is known to use three-dimensional polystyrene as a reducing agent for the thermoplastic polymer (Japanese Patent Publication No. Sho 51-12).
No. 76, JP-B-63-61344).

[0010]

However, in each of the above publications, three-dimensional polystyrene is generally used,
The shrinkage efficiency is lower than the two-dimensional thermoplastic polymer's shrinkage reducing agent, and the gloss of the surface of the obtained molded product is still insufficient because the amount of addition is limited. Has problems.

Further, the type of unsaturated polyester resin,
Even in the conventional method of increasing the surface gloss and surface smoothness by changing the curing agent, even in the conventional method, there is no known composition which can obtain a molded article having outstandingly excellent surface gloss and surface smoothness. In addition, there is a problem that the gloss of the surface of the obtained molded product is still insufficient.

A combination of molding conditions, such as setting a temperature difference between the surface on the front side of the molded article and the surface on the back side of the mold, is used for SMC and BMC. A thick molded product is produced by press molding. In the conventional case, the surface smoothness and gloss are slightly improved, but even in this case, a molded product with particularly excellent gloss cannot be obtained, and the resulting molded product is not obtained. There is a problem that the gloss of the product surface is still insufficient.

[0013]

The unsaturated polyester resin composition according to the present invention has been developed in order to solve the above-mentioned problems.
An unsaturated polyester, a polymerizable monomer copolymerizable with the unsaturated polyester, a three-dimensional polystyrene as a low-shrinking agent, and a compound represented by the following general formula (I):

[0014]

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(In the above formula, R ¹ is an alkyl group having 5 or more carbon atoms, R ² is a phenyl group, a substituted phenyl group or —OR ³ [R ³ is an alkyl group].) And a curing agent. In the present specification, a resin containing an unsaturated polyester and a polymerizable monomer copolymerizable with the unsaturated polyester is referred to as an unsaturated polyester resin. The unsaturated polyester resin composition further comprises:
It is preferable to include an unsaturated polyester having a hydrogenated bisphenol A skeleton of 10 mol% or more.

According to the above configuration, by using the curing agent represented by the general formula (I) and the three-dimensional polystyrene as a low-shrinking agent, the unsaturated polyester resin composition can be used as an unsaturated polyester resin. A molded article obtained by curing by copolymerization of a polyester and a polymerizable monomer has improved surface gloss and surface smoothness, and thus it is possible to obtain a molded article having an excellent surface condition.

In order to solve the above-mentioned problems, another unsaturated polyester resin composition of the present invention comprises an unsaturated polyester having a hydrogenated bisphenol A skeleton of 10 mol% or more, and a polymerizable copolymerizable with the unsaturated polyester. And a curing agent represented by the above general formula (I).

According to the above structure, the unsaturated polyester resin composition has a curing agent represented by the general formula (I) and a hydrogenated bisphenol A skeleton of not less than 10 mol% in the unsaturated polyester. The surface gloss and surface smoothness of a molded product obtained by curing by copolymerization of an unsaturated polyester and a polymerizable monomer are improved, and a molded product having an excellent surface state can be obtained.

R ¹ in the above curing agent is represented by the following general formula (II)

[0020]

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(R ⁴ in the above formula represents an alkyl group having 2 or more carbon atoms), and R ² in the curing agent is preferably a phenyl group.

According to the above arrangement, the use of the curing agent of the above general formula (I) defined by the above general formula (II) allows the surface gloss and surface smoothness of a molded article as a cured product. Is particularly improved, and it is possible to obtain a molded article having an excellent surface condition.

Hereinafter, the present invention will be described in detail. The unsaturated polyester resin composition according to the present invention is an unsaturated polyester, a polymerizable monomer copolymerizable with the unsaturated polyester, and three-dimensional polystyrene as a low shrinkage agent,
And a curing agent represented by the general formula (I). The unsaturated polyester preferably has a hydrogenated bisphenol A skeleton of 10 mol% or more.

The unsaturated polyester used in the present invention is produced, for example, by using, as raw materials, all polybasic acid components and alcohol components to be unsaturated polyester.

The above-mentioned polybasic acid component comprises at least one kind of polybasic acid. As the polybasic acid, specifically, for example, maleic acid, maleic anhydride, fumaric acid,
Unsaturated dibasic acids such as itaconic acid, itaconic anhydride, mesaconic acid, citraconic acid, citraconic anhydride; phthalic acid,
Saturated dibasic acids such as phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, sebacic acid, and heptic acid; trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic acid dianhydride Tribasic or higher polybasic acid such as a product; These polybasic acids may be used alone or in combination of two or more. In addition, the ratio of the unsaturated polybasic acid to the total polybasic acid component is desirably 70% or more in molar ratio.

The above-mentioned alcohol component comprises at least one kind of alcohol. As the alcohol, specifically, for example, ethylene glycol and a multimer thereof,
Glycols such as propylene glycol and its multimers, diethylene glycol, dipropylene glycol, neopentyl glycol, butanediol, hexanediol, and hydrogenated bisphenol; trifunctional or higher alcohols such as glycerin, trimethylolpropane, and pentaerythritol; ethylene oxide, propylene oxide Epoxides; and the like. These alcohols
Only one type may be used, or two or more types may be used in combination.

Among the unsaturated polyesters used, those containing a hydrogenated bisphenol A (HBPA) skeleton of 10 mol% or more were found to be heat-shrinkable upon cooling after molding in molded articles obtained using the above unsaturated polyesters. And the surface condition and surface gloss of the molded article can be further improved. Such HBPA content (mol
%) Is calculated by [HBPA (mol) / [total acid component (mol) + total alcohol component (mol)]] × 100 based on the number of moles of each component constituting the unsaturated polyester.

The method for producing the unsaturated polyester according to the present invention is not particularly limited. Reaction conditions such as a reaction temperature and a reaction time may be appropriately set according to, for example, the type and combination of all polybasic acid components and alcohol components to be unsaturated polyesters, or desired physical properties of a molding material. .

The condensation reaction in the above production method is more preferably performed in an atmosphere of an inert gas such as nitrogen gas. The degree of progress of the condensation reaction can be recognized by measuring the acid value and viscosity of the condensate.

The polymerizable monomer copolymerizable with the unsaturated polyester is not particularly limited as long as it has an ethylenic double bond copolymerizable with the unsaturated polyester. Specifically, styrene, methyl methacrylate, vinyl acetate, trimethylolpropane trimethacrylate, vinyltoluene, diallyl phthalate and the like are mentioned, and styrene is particularly preferable because of its excellent solubility in the obtained unsaturated polyester. . The amount of the polymerizable monomer to be added is not particularly limited, but may be 10 to the total weight of the unsaturated polyester resin.
It is preferably added in a proportion within a range of from 70 to 70% by weight, and more preferably in a range of from 20 to 50% by weight.

The low-shrinking agent may be any one containing three-dimensional polystyrene, but the amount of the low-shrinking agent is based on 100 parts by weight of the unsaturated polyester resin.
Preferably it is in the range of 5 to 30 parts by weight, more preferably 1 to 30 parts by weight.
Those containing in the range of 0 to 20 parts by weight are used.

If the amount of the low-shrinkage agent is less than the above range, the resulting unsaturated polyester resin composition has a large shrinkage due to curing during heat compression molding. For this reason, the molded article obtained from the unsaturated polyester resin composition undergoes deformation such as cracking and warpage, and
The smoothness of the molded product surface is impaired.

When the amount of the low-shrinkage agent is larger than the above range, the resulting unsaturated polyester resin composition is cured while causing the low-shrinkage agent to coagulate during heat compression molding. For this reason, the gloss of the obtained molded article is impaired.

The three-dimensional polystyrene refers to a three-dimensional cross-linked structure obtained by polymerizing a styrene monomer alone or a styrene monomer and a monomer copolymerizable therewith in the presence of a cross-linking agent. Is a crosslinked polymer having In the obtained three-dimensional polystyrene, the crosslink density is 0.2 to 30%, more preferably 0.5 to 10%.
% Is desirably adjusted.

As the copolymerizable monomer,
For example, the aforementioned monomer having an ethylenic double bond is suitable, but is not particularly limited. Examples of the crosslinking agent include divinylbenzene, divinylbenzene derivatives such as divinyltoluene, alkyne glycol diacrylate derivatives such as ethylene glycol diacrylate, alkyne glycol dimethacrylate derivatives such as ethylene glycol dimethacrylate, and polyfunctional groups such as diallyl phthalate. It is not particularly limited as long as it is a monomer.

Further, a thermoplastic polymer or a thermoplastic copolymer such as polystyrene, polymethyl methacrylate, polyethylene, polypropylene, saturated polyester, polyamide and polyurethane can be used in combination as a low-shrinking agent. It is.

The curing agent is a peroxyester in which a tertiary alkyl group having 5 or more carbon atoms, preferably 5 to 9 carbon atoms, is bonded to a peroxide group. Further, as the organic residue represented by R ² in the above general formula (I), which represents the above curing agent, specifically, for example, an alkyl group, an alkoxy group, a cyclohexyl group, a cyclohexenyl group Phenyl group, phenoxy group and the like.
Further, the above phenyl group or phenoxy group may further have a substituent such as an alkyl group.

The alkyl group represented by R ⁴ in the above general formula (II), which represents R ¹ in the above general formula (I), preferably has 2 to 6 carbon atoms. Or, it is more preferable that it is branched. And, as the peroxy acid ester, a peroxide in which the organic residue represented by R ² in the above general formula (I) is a phenyl group, that is,
Peroxybenzoic acid esters are particularly preferred.

The 10-hour half-life temperature of the above peroxyacid ester is in the range of 70 ° C. to 120 ° C. Specific examples of the peroxy acid ester include, for example, t-amyl peroxybenzoate (t-pentyl peroxybenzoate), t-hexyl peroxybenzoate, t-hexyl peroxy monoisopropyl carbonate, t-amyl peroxy-3,5,5 -Trimethylhexanoate, t-hexylperoxy-3,5,5-trimethylhexanoate and the like, but are not particularly limited thereto. These peroxy esters may be used alone,
Further, two or more kinds may be used in combination. Of the peroxy acid esters exemplified above, t-amyl peroxybenzoate and t-hexyl peroxybenzoate are particularly preferred.

The amount of the peroxyacid ester to be added to the unsaturated polyester resin having the above constitution is not particularly limited, and may be appropriately set according to the type of the unsaturated polyester or the polymerizable monomer. The amount is more preferably in the range of 0.05 to 10 parts by weight, more preferably in the range of 0.5 to 5 parts by weight, based on 100 parts by weight of the saturated polyester resin. If the amount of the peroxy acid ester is less than the above range, or if it is more than the above range, it may not be possible to obtain an unsaturated polyester resin composition capable of obtaining a molded article having excellent surface gloss. There is.

Further, the unsaturated polyester resin composition of the present invention may contain both of the above-mentioned peroxyacid ester and another curing agent different therefrom. In the case where both of the above are used in combination, the ratio of the peroxyacid ester in the curing agent that is the sum of the two is 30
It is preferably at least 50% by weight, more preferably at least 50% by weight. Further, as another curing agent different from the above-mentioned peroxy acid ester, a curing agent having a 10-hour half-life temperature lower than that of the above-mentioned peroxy acid ester by 5 ° C. or more is preferable.

Thereby, for example, even when a low-shrinking agent and a coloring agent are added, the moldability is excellent, and
It is possible to provide an unsaturated polyester resin composition capable of obtaining a molded product having no unevenness in color and having excellent surface gloss.

In the molding material containing the unsaturated polyester resin composition according to the present invention, the above-mentioned polymerizable monomer may be added if necessary, and a reinforcing material, an auxiliary material (additive) Etc. may be included. Specific examples of the above-mentioned auxiliary materials include a filler, a colorant, a polymerization inhibitor, a release agent, a thickener, a thickener, a polymerization regulator, and a viscosity modifier. Unsaturated polyester resin compositions containing such reinforcing materials and auxiliary materials include, for example, SMC, BM
Suitable as C.

Specific examples of the reinforcing material include inorganic fibers such as glass fiber carbon fiber, metal fiber, and fiber made of ceramic, organic fiber made of aramid and polyester, and natural fiber. There is no particular limitation. Further, the amount of the reinforcing material added is not particularly limited. For example, the amount of glass fiber, the fiber length, the fiber diameter, the number of converging fibers, and the like may be appropriately set according to the molding conditions of the molding material, the use of the molded product, and the like. The amount of the reinforcing material such as glass fiber is added to the total amount of the molding material containing the unsaturated polyester resin of the present invention.
It is preferably in the range of 1% to 30% by weight.

Examples of the filler include inorganic fillers such as calcium carbonate, aluminum hydroxide, magnesium carbonate, barium sulfate, calcium sulfate, alumina, stone powder, glass powder, carion, clay, talc and silica. Agents and organic fillers, but are not particularly limited. Of these, aluminum hydroxide and calcium carbonate are preferred.

One of these fillers may be used alone, or two or more thereof may be used in combination. The amount of the filler to be added is not particularly limited, and may be appropriately set according to the molding conditions of the molding material or the use of the molded article.
It is preferably in the range of 50 to 400 parts by weight, more preferably in the range of 250 to 350 parts by weight.
By properly selecting the filler, a so-called transparent feeling can be imparted to the molded article.

The colorant is not particularly limited, and various colorants conventionally used for unsaturated polyester resins can be used. The amount of the colorant to be added is not particularly limited, and may be appropriately set according to the use of the molded article.

Specific examples of the polymerization inhibitor include hydroquinone, methylhydroquinone, 1,4-benzoquinone (p-benzoquinone), t-butylhydroquinone, pt-butylcatechol, toluhydroquinone, naphthoquinone and hydroquinone monomethyl. Examples include ether, phenothiazine, and copper naphthenate, but are not particularly limited. One of these polymerization inhibitors may be used alone, or two or more thereof may be used in combination. The addition amount of the polymerization inhibitor is not particularly limited.

Specific examples of the release agent include fatty acids such as stearic acid and lauric acid, and metal salts thereof, but are not particularly limited. These release agents may be used alone or in combination of two or more. The amount of release agent added is
It is not particularly limited, and may be appropriately set according to the type of the release agent, the molding conditions of the molding material, and the like.

The thickening agent may be any compound that can react with a polybasic acid and / or alcohol, and specifically includes, for example, a polyfunctional isocyanate; a polyvalent metal such as magnesium oxide, calcium oxide, and zinc oxide. Oxides; polyvalent metal hydroxides such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide; and the like. Only one type of these thickeners may be used, or two or more types may be used in combination.

Among the above-mentioned thickeners, polyvalent metal oxides and polyvalent metal hydroxides are more preferable, alkaline earth metal oxides and alkaline earth metal hydroxides are more preferable, and magnesium oxide And calcium hydroxide are most preferred. The amount of the thickener used is not particularly limited, and may be appropriately set according to the weight average molecular weight, the viscosity and the like of the unsaturated polyester. Instead of performing the above-mentioned chemical thickening using a thickener, physical thickening can also be performed using a polymer having crystallinity at ordinary temperature. Further, chemical thickening and physical thickening can be used in combination.

Generally, unsaturated polyesters are
When the weight average molecular weight is 7,000 or more, good thickening can be performed using a polyvalent metal oxide and / or a polyvalent metal hydroxide. Therefore, when thickening, the unsaturated polyester resin and the filler do not separate. In addition, since good thickening can be performed, the releasability of the release film used when packing the molding material is improved. Thereby, the handleability during the molding operation is improved.

Further, when the viscosity is increased by using a polyvalent metal oxide and / or a polyvalent metal hydroxide, the flowability of the molding material obtained from the unsaturated polyester resin composition becomes better, and Excellent. Therefore, occurrence of molding defects and defective filling is avoided.

The above-mentioned viscosity reducing agent, polymerization regulator and viscosity regulator are not particularly limited, and various viscosity reducing agents, polymerization regulators and viscosity regulators conventionally used for unsaturated polyester resins are used. Agents can be used.

In the method for producing a molding material containing the above-mentioned unsaturated polyester resin composition, when the molding material is SMC, a peroxyacid ester is added to the unsaturated polyester resin, It is preferable to mix the agent, the polymerizable monomer, and the auxiliary material, and then impregnate the reinforcing material.

When the molding material is BMC, a peroxy acid ester is added to the unsaturated polyester resin, and at the same time, a low-shrinking agent, a polymerizable monomer, a thickener, a reinforcing material, and an auxiliary material are used. Is preferred.

A molded article obtained by molding the above molding material is excellent in appearance such as moldability, durability, water resistance, hot water resistance and surface gloss. It is suitably used for housing equipment. In addition, the molding method and molding conditions of the housing equipment member are not particularly limited.

[0058]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Note that "parts" described in each of the examples and comparative examples indicates "parts by weight".
“%” Indicates “% by weight”. First, each production method of each unsaturated polyester resin used in each Example and each Comparative Example will be described below as Reference Examples 1 to 3.

Reference Example 1 980 g (1.0 mol) of maleic anhydride as an acid component and hydrogen as an alcohol component were placed in a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube, and a stirrer. Bisphenol A 720g
(0.3 mol), 433 g (0.57 mol) of propylene glycol,
117 g (0.09 mol) of dipropylene glycol and 94 g (0.09 mol) of neopentyl glycol were charged.

Next, after the inside of the reaction vessel was replaced with nitrogen gas, the temperature was raised to 215 ° C., and the mixture was stirred for about 14 hours while maintaining the reaction temperature, thereby completing the reaction and obtaining an unsaturated polyester. The acid value of the unsaturated polyester measured by a predetermined method was 26 mgKOH / g.

Thereafter, 0.01 part of hydroquinone as a polymerization inhibitor was added to 100 parts of the unsaturated polyester, and 75 parts of a styrene monomer as a polymerizable monomer were dissolved to obtain a hydrogenated bisphenol A skeleton. To 10
Resin (1), which is a liquid unsaturated polyester resin composed of an unsaturated polyester having at least mol% and a polymerizable monomer, was obtained.

REFERENCE EXAMPLE 2 980 g (1.0 mol) of maleic anhydride as an acid component and hydrogen as an alcohol component were placed in a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube, and a stirrer. Bisphenol A 240g
(0.1 mol), 463 g (0.61 mol) of propylene glycol,
347 g (0.33 mol) of neopentyl glycol was charged.

Next, after the inside of the reaction vessel was replaced with nitrogen gas, the temperature was raised to 215 ° C., and the mixture was stirred for about 14 hours while maintaining the reaction temperature to complete the reaction and obtain an unsaturated polyester. The acid value of the unsaturated polyester measured by a predetermined method was 26 mgKOH / g.

Thereafter, 0.01 parts of hydroquinone as a polymerization inhibitor was added to 100 parts of the unsaturated polyester, and 75 parts of a styrene monomer as a polymerizable monomer were dissolved to form 10 parts of the bisphenol A skeleton. mol%
Thus, a resin (2), which is a liquid unsaturated polyester resin, composed of an unsaturated polyester having less than and a polymerizable monomer was obtained.

REFERENCE EXAMPLE 3 980 g (1.0 mol) of maleic anhydride as an acid component and propylene as an alcohol component were placed in a reaction vessel equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube, and a stirrer. Glycol 638g (0.8
4 mol), 172 g (0.13 mol) of dipropylene glycol, and 139 g (0.13 mol) of neopentyl glycol.

Next, after the inside of the reaction vessel was replaced with nitrogen gas, the temperature was raised to 215 ° C., and the mixture was stirred for about 12 hours while maintaining the reaction temperature to complete the reaction, thereby obtaining an unsaturated polyester. The acid value of the unsaturated polyester measured by a predetermined method was 26 mgKOH / g.

Thereafter, 0.01 part of hydroquinone as a polymerization inhibitor was added to 100 parts of the unsaturated polyester, and 75 parts of a styrene monomer as a polymerizable monomer were dissolved to obtain a hydrogenated bisphenol A skeleton. (3), which is a liquid unsaturated polyester resin composed of an unsaturated polyester containing no and a polymerizable monomer.

Next, each of the curing agents A to F used in each of the following Examples and Comparative Examples will be described.
Curing agent A is, t-hexyl peroxybenzoate (manufactured by NOF Corporation, trade name: Perhexyl Z) is, R ⁴ in the general formula (II) is a propyl group (C ₃ H ₇ -) is the general formula ( R ² in I) is a phenyl group (—C ₆ H ₅ ).

The curing agent B is t-amyl peroxybenzoate (manufactured by Kayaku Akzo, trade name: KD-1), and R ⁴ in the general formula (II) is an ethyl group (C ₂ H _5- ). ,
R ² in the general formula (I) is a phenyl group (—C ₆ H ₅ ).

The curing agent C is t-butyl peroxybenzoate (trade name: Perbutyl Z, manufactured by NOF Corporation), and R ⁴ in the general formula (II) is a methyl group (CH _3- ). R ² in (I) is a phenyl group (—C
₆ H ₅ ).

The curing agent D is t-butylperoxyisopropyl carbonate (trade name: Kayacaron B1C-75, manufactured by Kayaku Akzo).
¹ is a t-butyl group, and R ² is —O—CH (CH ₃ ) ₂ .

The curing agent E is t-hexyl peroxyisopropyl monocarbonate (trade name: Perhexyl I, manufactured by NOF Corporation), and R ¹ in the general formula (I) is t-hexyl.
A hexyl group, and R ² is —O—CH (CH ₃ ) ₂ .

The curing agent F is 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane (manufactured by NOF Corporation,
(PerhexaTMH), a peroxyketal-based curing agent having a 10-hour half-life temperature of 12 ° C. lower than that of the curing agent A, and represented by the following chemical formula (III).

[0074]

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[Examples 1 to 9 and Comparative Examples 1 to 8]
At the respective composition ratios shown in Tables 1 and 2, the respective components were sufficiently kneaded with a kneader to produce an unsaturated polyester resin composition. The three-dimensional polystyrene used was SGP-70C (trade name, manufactured by Soken Chemical Co., Ltd.), and the silane coupling agent was KBM-503 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.).

Further, glass fiber (1 mm or 6 m) as a reinforcing material was added to the unsaturated polyester resin composition.
m) was added in the amounts shown in Tables 1 and 2, followed by sufficient kneading using a kneader. By the above procedure, BMCs were obtained from the unsaturated polyester resin compositions described in Examples 1 to 9 and Comparative Examples 1 to 8, respectively.

Using 1900 g of each BMC obtained in this way, a mold (flat shape) in which the mold surface on the front side of the molded article was heated to 140 ° C. and the mold surface on the back side was heated to 130 ° C.
Heat compression molding (pressing force: 75 kgf / cm ² ) at 300 × 30
A flat molded product having a square shape of 0 mm and a thickness of about 10 mm was obtained.

The gloss on the product surface side, that is, the surface side (140 ° C. side) of each flat molded product obtained in this manner was measured according to JIS K
According to 7105, use a gloss meter (60 ° gloss)
Each time, measure the average value of the three measurements, the gloss (gr
oss value). Tables 1 and 2 show the results.
Indicated according to The evaluation of glossiness shown in Tables 1 and 2 was performed based on the following criteria.

Evaluation Gloss degree (60 °) range Remarks ○ 90 or more Particularly excellent in gloss ○ 85 or more and less than 90 Excellent in gloss △ 80 or more and less than 85 Glossy × less than 80 Normal surface state of BMC

[0080]

[Table 1]

[0081]

[Table 2]

As is clear from Tables 1 and 2, when each of the peroxyacid esters described in Comparative Examples 1 and 2 having a tertiary alkyl group having 4 carbon atoms bonded to a peroxide group was used as a curing agent, respectively. It can be seen that the gloss of the obtained molded article was inferior.

Further, from Comparative Examples 3 to 8, the curing agent represented by a peroxy acid ester in which a tertiary alkyl group having 5 or more carbon atoms is bonded to a peroxide group, and a low shrinkage resin containing three-dimensional polystyrene Or a curing agent represented by a peroxy acid ester having a tertiary alkyl group having 5 or more carbon atoms bonded to a peroxide group, and an unsaturated polyester having a hydrogenated bisphenol A skeleton of 10 mol% or more It is understood that the combination with is essential in the present invention.

[0084]

As described above, the unsaturated polyester resin composition of the present invention comprises an unsaturated polyester, a polymerizable monomer copolymerizable with the unsaturated polyester, a tertiary alkyl group having 5 or more carbon atoms. Comprises a curing agent represented by a peroxy acid ester bonded to a peroxide group, and a low-shrinking agent containing three-dimensional polystyrene.

Therefore, in the above configuration, when molded, the unsaturated polyester used can exhibit excellent moldability and durability, and the combination of the curing agent and the low-shrinking agent provides excellent molding properties. There is an effect that a molded article having gloss can be obtained.

As described above, another unsaturated polyester resin composition of the present invention comprises a curing agent represented by a peroxy acid ester having a tertiary alkyl group having 5 or more carbon atoms bonded to a peroxide group, 1 hydrogenated bisphenol A skeleton
The composition includes an unsaturated polyester having 0 mol% or more and a polymerizable monomer copolymerizable with the unsaturated polyester.

Therefore, when the above configuration is formed,
The molded product having excellent moldability and durability due to the unsaturated polyester used, and having excellent gloss due to the combination of the curing agent and the unsaturated polyester having a hydrogenated bisphenol A skeleton of 10 mol% or more. Is obtained.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI (C08L 67/06 25:06)

Claims (4)

[Claims] 1. An unsaturated polyester, a polymerizable monomer copolymerizable with the unsaturated polyester, a three-dimensional polystyrene as a low-shrinking agent, and the following general formula (I): (R ¹ in the above formula is an alkyl group having 5 or more carbon atoms, R ²
Is a phenyl group, a substituted phenyl group or -OR ³
[R ³ is an alkyl group]). 2. The unsaturated polyester resin composition according to claim 1, wherein the unsaturated polyester has a hydrogenated bisphenol A skeleton at 10 mol% or more. 3. A hydrogenated bisphenol A skeleton comprising 10 mol%
An unsaturated polyester having the above, a polymerizable monomer copolymerizable with the unsaturated polyester, and a compound represented by the following general formula (I): (R ¹ in the above formula is an alkyl group having 5 or more carbon atoms, R ²
Is a phenyl group, a substituted phenyl group or -OR ³
[R ³ is an alkyl group]). (4) R ² in the curing agent is a phenyl group;
And R ¹ in the curing agent is represented by the following general formula (II): ^{4. The} unsaturated polyester resin composition according to claim 1, wherein R ⁴ in the above formula is represented by an alkyl group having 2 or more carbon atoms. 5.