JPH10237289A - Production of unsaturated polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an unsaturated polyester resin composition which has good handleability, is excellent in flowability even at low temperature of under low pressure and makes it possible to easily and accurately mold an article with good appearance, by incorporating a thermally fluidizing agent in producing an unsaturated polyester resin by mixing an unsaturated polyester polymer at high temperature with a polymerizable monomer. SOLUTION: The unsaturated polyester polymer used comprises a linear polymer obtained by the polycondensation of an unsaturated dibasic acid and a glycol, and if necessary, a saturated dibasic acid. The process for producing an unsaturated polyester resin form a mixture of the unsaturated polyester polymer and a polymerizable monomer comprises polymerizing an unsaturated dibasic acid component and a glycol component by heating to 100-220 deg.C in a reactor, and introducing the obtained unsaturated polyester polymer in a molten state into a melting tank containing a polymerizable monomer to mix them. 100 pts.wt. unsaturated polyester resin containing 40-80wt.% unsaturated polyester polymer is mixed with 0.1-20 pts.wt. thermally fluidizing agent having a melting point of 40-150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an unsaturated polyester resin composition.

[0002]

2. Description of the Related Art A resin composition obtained by adding a filler, a releasing agent, a curing agent, a thickener, and the like to an unsaturated polyester resin is impregnated into a reinforcing fiber material such as glass fiber to form a sheet or bulk. The unsaturated polyester resin molding material thus obtained is called a sheet molding compound (SMC) or a bulk molding compound (BMC). SMC and BMC are mainly compression molded and widely used for housing equipment, industrial parts or automobile parts.

[0003] These molding materials are often subjected to compression molding under heating by a compression molding machine. However, in the compression molding method, it is necessary to introduce a large molding machine in order to expand applicable products (increase in size and variety).
There is a drawback in that the cost burden becomes extremely large due to the necessity of expensive die investment.

[0004] Conventional compression molding conditions include a temperature of 12 ° C.
The pressure is about 0 to 160 ° C. and the pressure is about 80 to 100 kg / cm ^2. However, if the compression molding can be performed at a lower temperature or a lower pressure, the above cost burden can be reduced.

[0005] However, in the conventional compression molding, when compression molding is performed at a low temperature or a low pressure, a thinned portion, a cavity, or a pinhole is easily generated on the surface of a molded product. The nests and pinholes not only impair the appearance of the molded article, but also may adversely affect the mechanical properties and durability of the molded article. Therefore,
In order to reduce these disadvantages, material techniques have been devised.

For example, as disclosed in Japanese Patent Publication No. Sho 60-16471, in order to increase the fluidity under low pressure, the viscosity is reduced by using calcium hydroxide as a thickener, and the viscosity of the molding material is reduced. Attempts have been made to lower However, in this method, the molding material becomes sticky, and not only the workability such as the release property and the cutting of the release film such as the polyethylene film covering the molding material is reduced,
There was a drawback that nests and pinholes were easily formed on the surface of the molded product.

Further, a commercially available liquid viscosity reducing agent (for example,
A method of adding “BYK-W995” manufactured by BYK Chemie and “Spardine V-203” manufactured by Takemoto Yushi Co., Ltd.) is also conceivable, but the viscosity after thickening is liable to decrease, resulting in reduced workability and immersion in hot water. Because it is easy to discolor later, SMC
It was not possible to apply to plumbing products, which is a large field of application.

Therefore, the present inventors have found that, by blending a specific solid heating fluidizing agent, the material has excellent handleability during molding and excellent fluidity even under low pressure. However, commercially available products of such a heating fluidizing agent generally have a relatively large particle size, and are generally SM-based.
In the production process of C and BMC, the dispersion of the heating fluidizing agent becomes insufficient, and there is a possibility that the performance may vary.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an unsaturated polyester resin composition having good handleability, excellent flowability even at low temperatures or low pressures, and capable of easily and accurately molding a molded article having a good appearance. An object of the present invention is to provide a method for manufacturing a product.

[0010]

The process for producing an unsaturated polyester resin composition according to the present invention comprises mixing an unsaturated polyester polymer at a high temperature with a polymerizable monomer to obtain an unsaturated polyester polymer content of 40%. To produce an unsaturated polyester resin of 10 to 80% by weight.
It is characterized in that 0.1 to 20 parts by weight of a heating fluidizer having a melting point of 40 to 150 ° C. is mixed with 0 parts by weight.

The unsaturated polyester polymer used in the present invention is a linear polymer obtained by polycondensing an unsaturated dibasic acid, glycol and, if necessary, a saturated dibasic acid.

As the unsaturated dibasic acid, for example, maleic anhydride, fumaric acid, itaconic acid, citraconic acid and the like are used. Examples of the glycol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, bisphenol A Ethylene oxide adduct, neopentyl glycol and the like.

The saturated dibasic acids include, for example, phthalic anhydride, orthophthalic acid, isophthalic acid, terephthalic acid, adipic acid, succinic acid, tetrachlorophthalic acid, and heptic acid.

An industrial method for producing an unsaturated polyester resin comprising a mixture of the above unsaturated polyester polymer and a polymerizable monomer is generally carried out by reacting an unsaturated dibasic acid component and a glycol component in a reaction vessel in a reaction vessel. After heating to about 220 ° C. to obtain a molten unsaturated polyester polymer, the molten unsaturated polyester polymer is introduced into a dissolving vessel containing a polymerizable monomer with stirring and mixed. Can be obtained.

In the production method of the present invention, a heating fluidizing agent is added and mixed in the process of mixing the unsaturated polyester polymer in the molten state and the polymerizable monomer in a dissolving vessel. This dissolving tank is at a high temperature to introduce the unsaturated polyester polymer in a molten state, and the heating fluidizing agent is in a state of being easily dissolved or finely dispersed in the unsaturated polyester polymer and the polymerizable monomer. . Also, if necessary,
You may heat with oil, warm water, a heater, etc.

Examples of the polymerizable monomer include styrene, dichlorostyrene, vinyltoluene, vinyl acetate, methacrylic acid, methacrylic acid ester, acrylic acid, acrylic acid ester, diallyl phthalate, and the like. It is.

In the unsaturated polyester resin, the content of the polymerizable monomer is 60 to 20% by weight based on the content of the unsaturated polyester polymer of 40 to 80% by weight. When the content of the polymerizable monomer is more than 60% by weight, the viscosity of the unsaturated polyester resin is lowered, so that the production of SMC cannot be performed. descend.

As a method of adding a heating fluidizing agent to the unsaturated polyester resin, a heating fluidizing agent is added to a polymerizable monomer in a dissolving tank in advance, and then the unsaturated polyester resin in a molten state is added. Mixing the coalescing, adding the heating fluidizer at the same time as adding the unsaturated polyester polymer in the molten state to the polymerizable monomer in the dissolving tank. After mixing with the coalescing, the method is added to the polymerizable monomer in the dissolving tank.

As the above-mentioned heating fluidizer, the unsaturated polyester resin composition at ordinary temperature can be used without lowering the viscosity.
A melting point of 40 to 150 ° C., preferably a melting point of 40 to 150 ° C., which can significantly lower the viscosity by heating during press molding.
Compounds at １２０120 ° C. are used. If the melting point of the heating fluidizing agent is less than 40 ° C., the handleability of the unsaturated polyester resin composition before molding becomes poor, and if it exceeds 150 ° C., the decrease in viscosity during heating and molding is small, and the effect of improving fluidity is small. Become.

The above-mentioned heating fluidizer has a melting point of 40-1.
Compounds called lubricants at 50 ° C. are preferably used, for example, hydrocarbon lubricants such as polyethylene wax and liquid paraffin; higher fatty acid lubricants such as stearic acid; fatty acid amide lubricants such as fatty acid amide and alkylene bis fatty acid amide; Ester lubricants such as monohydric alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids and polyglycol esters of fatty acids; alcoholic lubricants such as aliphatic alcohols, polyhydric alcohols, polyglycols and polyglycerols; lubricants such as metal soaps; No. These may be used alone or in combination of two or more.

The use amount of the above-mentioned heating fluidizer is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the unsaturated polyester resin. If the amount of the heating fluidizing agent is less than 0.1 part by weight, the fluidity during molding is insufficient, and if it exceeds 20 parts by weight, the mechanical strength of the molded article is reduced.

More preferred heating fluidizers include the following compounds (a) to (f). (A) a monohydric aliphatic alcohol having a melting point of 40 to 100 ° C; (b) a sorbitan fatty acid ester having a melting point of 40 to 100 ° C; (c) a glycerin fatty acid ester having a melting point of 40 to 100 ° C; Polyol fatty acid ester (e) Higher alcohol fatty acid ester having a melting point of 40 to 120 ° C (f) Fatty acid amide having a melting point of 80 to 150 ° C These compounds may be used alone or in combination of two or more.

The monohydric aliphatic alcohol (a) is a compound having a melting point of 40 to 100 ° C., preferably 45 to 80 ° C., wherein one hydrogen of the aliphatic hydrocarbon is substituted with a hydroxyl group. If the melting point is less than 40 ° C., the handleability of the unsaturated polyester resin composition before molding becomes poor, and if it exceeds 100 ° C., the fluidity at the time of heat molding decreases. In particular, carbon number 10
It is preferable to use a compound in which hydrogen bonded to a terminal carbon of an aliphatic hydrocarbon having a carbon number of from 36 to 36 (more preferably from 10 to 25 in view of industrial availability) is substituted with a hydroxyl group.
The aliphatic hydrocarbon may be either a saturated hydrocarbon or an unsaturated hydrocarbon, and may be either branched or linear, but is more preferably a linear, saturated aliphatic hydrocarbon. Specific examples of the monohydric aliphatic alcohol (a) include cetyl alcohol, stearyl alcohol, behenyl alcohol, and the like.

The sorbitan fatty acid ester (b) is
Sorvit, a hexahydric alcohol (molecular formula C ₆ H ₁₄ O
It is a compound obtained by esterifying ₆ ) with a fatty acid and having a melting point of 40 to 100 ° C, preferably 50 to 80 ° C. Melting point 40 ° C
If it is less than 100 ° C., the handleability of the unsaturated polyester resin composition before molding will be poor, and if it exceeds 100 ° C., the fluidity during heat molding will be reduced. As fatty acids, those having 10 to 36 carbon atoms
It is preferable to use a compound in which hydrogen bonded to a terminal carbon of an aliphatic hydrocarbon having an aliphatic hydrocarbon (more preferably 10 to 25 in view of industrial availability) is substituted with a carboxyl group. The aliphatic hydrocarbon may be either a saturated hydrocarbon or an unsaturated hydrocarbon, and may be either branched or linear, but is more preferably a linear, saturated aliphatic hydrocarbon. Specific examples of the sorbitan fatty acid ester (b) include sorbitan palmitate, sorbitan stearate, sorbitan tristearate,
Sorbitan behenate, sorbitan tribehenate and the like can be mentioned.

The glyceryl fatty acid ester (c) is
Glycerin, which is a polyhydric alcohol, is esterified with a fatty acid.
° C. If the melting point is lower than 40 ° C., the handleability of the unsaturated polyester resin composition before molding becomes poor, and
If it exceeds 0 ° C., the fluidity at the time of heat molding decreases. As the fatty acid, those similar to those used in the above-mentioned sorbitan fatty acid ester (b) are used.

Specific examples of the glycerin fatty acid ester (c) include glycerin monopalmitate, glycerin monostearate, glycerin monooleate, glycerin monobehenate, glycerin mono 12-hydroxystearate, glycerin monocaprate, and glycerin monolau. Rate, glycerin mono-dipalmitate, glycerin mono-distearate, glycerin di-tristearate, glycerin mono-diolate, glycerin mono-dibehenate, glycerin mono-di-12-hydroxystearate and the like.

The neopentyl polyol fatty acid ester (d) is neopentyl glycol (also called 2,2)
-Dimethyl-1,3-propanediol), neopentyltriol (also called 2-hydroxymethyl-2-methyl-1,3-propanediol) or neopentyltetraol (also called pentaerythritol) A compound having a melting point of 40 to 120 ° C, preferably a melting point of 50 to 100 ° C, obtained by esterifying a polyol or a dimer of these neopentyl polyols linked by an ether bond with a fatty acid as a polyol component. is there.

Further, a neopentyl polyol obtained by esterifying two or more hydroxyl groups is preferably used. The neopentyl polyol includes a glycol type, a triol type and a tetraol type, and the dimer of these is, for example, one in which an ether bond is formed by dimerization.

Examples of the above fatty acids include the fatty acids used in the above-mentioned sorbitan fatty acid ester (b).

When the melting point of the neopentyl polyol fatty acid ester (d) is less than 40 ° C., the handleability of the unsaturated polyester resin composition before molding becomes poor, and
If the temperature exceeds ℃, the fluidity at the time of thermoforming decreases.

The neopentyl polyol fatty acid ester (d) is preferably a fatty acid ester of pentaerythritol or a fatty acid ester of dipentaerythritol, and specific examples thereof include (d) stearic acid ester of pentaerythritol and (d) And pentaerythritol behenate.

The higher alcohol fatty acid ester (e)
Is esterified higher alcohol and fatty acid, melting point 4
It is a compound at 0 to 120 ° C, preferably 50 to 100 ° C. If the melting point is less than 40 ° C., the handleability of the unsaturated polyester resin composition before molding becomes poor, and if it exceeds 120 ° C., the fluidity during heat molding is reduced. Higher alcohol is
10 to 36 carbon atoms (1 carbon atom due to industrial availability)
(Preferably 0 to 25) is a compound in which hydrogen bonded to a terminal carbon of an aliphatic hydrocarbon is substituted with a hydroxyl group, and the aliphatic hydrocarbon may be either a saturated hydrocarbon or an unsaturated hydrocarbon, It may be either branched or linear, but is more preferably a linear, saturated aliphatic hydrocarbon. Examples of the fatty acid include the same fatty acids as those used in the sorbitan fatty acid ester (b).

Usually, both higher alcohols and higher fatty acids are monovalent compounds, and examples thereof include monoester compounds containing these as constituents. Specific examples of the higher alcohol fatty acid ester (e) include stearyl stearate, behenyl behenate, cetyl myristate, and the like.

The fatty acid amide (f) is an amide synthesized from ammonia or an amino compound and a fatty acid, and has a melting point of 80 to 150 ° C., preferably 90 to 145.
° C. If the melting point is lower than 80 ° C., the handleability of the unsaturated polyester resin composition before molding becomes poor,
If it exceeds 0 ° C., the fluidity at the time of heat molding decreases. Examples of the fatty acid include the same fatty acids as those used in the sorbitan fatty acid ester (b). Specific examples of the fatty acid amide (e) include stearic acid amide, behenic acid amide, ethylenebisstearamide, ethylenebis (hydroxystearamide), ethylenebisoleic acid amide, and ethylenebiserucic acid amide. .

The amounts of the compounds (a) to (f) are as follows:
0.1 parts by weight based on 100 parts by weight of the unsaturated polyester resin.
To 20 parts by weight, more preferably 0.5 to 15 parts by weight.
Parts by weight. If the amount used is less than 0.1 parts by weight,
If the fluidity during molding decreases, and if it is more than 20 parts by weight,
Nests easily enter the surface of the molded product, and the mechanical strength is reduced. When the compounds (d) and (f) are used in an amount exceeding 10 parts by weight, the physical properties may be reduced.
0.1 parts by weight based on 100 parts by weight of the unsaturated polyester resin.
-10 parts by weight is preferred.

The unsaturated polyester resin composition obtained by the production method of the present invention contains, in addition to the unsaturated polyester resin and the heating fluidizing agent, inorganic filler particles, reinforcing fibers, a low-shrinking agent, a curing agent, Agents, thickeners, pigments and the like may be blended.

Examples of the inorganic filler particles include calcium carbonate, aluminum hydroxide, calcium sulfate,
Examples thereof include particles such as glass powder, talc, and mica, which may be used alone or in combination of two or more.

The particle size of the inorganic filler particles is preferably 0.1 to 100 μm, more preferably 0.1 to 100 μm.
5 to 60 μm. When the particle size is smaller than 0.1 μm, the viscosity of the resin composition increases and the reinforcing fibers described below are not sufficiently impregnated, and air is easily mixed into the material,
A nest easily enters a molded article. The particle size is 100 μm
If it is larger, the specific surface area of the particles becomes smaller,
The effect of the heating fluidizer is less likely to be obtained, and the fluidity is reduced.

The amount of the inorganic filler particles used is preferably 50 to 350 parts by weight, more preferably 60 to 300 parts by weight, based on 100 parts by weight of the unsaturated polyester resin. If the amount is less than 50 parts by weight, the handleability of the unsaturated polyester resin composition is reduced. If the amount is more than 350 parts by weight, the viscosity is greatly increased and the fluidity at the time of molding is reduced. It becomes easy to mix air inside,
A nest easily enters a molded article.

Examples of the reinforcing fibers include glass fibers, carbon fibers, asbestos fibers, whiskers, organic synthetic fibers,
Natural fibers and the like can be mentioned, and glass fibers are suitably used in terms of physical properties and cost. As the glass fiber, in addition to a case where a fixed length or continuous fiber is used as it is, a mat-like or cloth-like fiber is also used. For example, in the case of glass fiber, a chopped strand obtained by cutting a strand into a predetermined length, a chopped strand mat formed by bonding a chopped strand with a binder and forming a mat shape, and the like are used. As a fiber having a fiber length of a certain length, usually 1 to 8
The one of 0 mm is used. When the fiber length is shorter than 1 mm, there is no reinforcing effect, and when the fiber length is longer than 80 mm, the viscosity is increased and the moldability may be deteriorated. In addition, the directionality of the fibers in the unsaturated polyester resin composition is not limited to randomization, but may be arbitrary, such as one arranged in one direction, one arranged in an X shape.

The amount of the reinforcing fibers is preferably 2 to 50% by weight, more preferably 3 to 40% by weight, based on the whole unsaturated polyester resin composition containing the reinforcing fibers. Range. The amount of reinforcing fiber is 2
When the content is less than the weight%, the handling property of the material is reduced, and
Since there is no reinforcing effect, the molded article is liable to crack and bend. If it is more than 50% by weight, the viscosity increases and the fluidity deteriorates.

Examples of the low shrinkage agent include polystyrene, polyvinyl acetate, polymethyl methacrylate, polyethylene, polyε-caprolactone, saturated polyester, polyvinyl chloride, polybutadiene, styrene-acrylic acid copolymer, and styrene-vinyl acetate. Copolymers, ethylene-vinyl acetate copolymers, vinyl chloride-vinyl acetate copolymers, acrylonitrile-styrene copolymers and the like can be mentioned.

The amount of the low shrinkage agent is preferably 3 to 40 parts by weight based on 100 parts by weight of the unsaturated polyester resin.

Examples of the curing agent include tertiary butyl peroxyisobutyrate, tertiary butyl peroxy 2-ethylhexanoate, tertiary amyl peroxy 2-ethylhexanoate, 2,4,4
4-trimethylpentylperoxy 2-ethylhexanoate, tert-butylperoxypivalate, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, tert-butylperoxy 3,5,5-trimethylhexano Organic peroxides such as ate, 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, benzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide and the like.

Examples of the release agent include zinc stearate and calcium stearate, and examples of the thickener include magnesium oxide, magnesium hydroxide, calcium oxide and zinc oxide.

The unsaturated polyester resin composition may be formed into a sheet or a bulk, and the sheet-shaped molding material (SMC or TMC) is formed using a known machine. At this time, the unsaturated polyester resin composition excluding the reinforcing fibers is kneaded and stirred in advance with equipment such as a stirrer.

For example, when producing SMC, the unsaturated polyester resin composition is applied to a uniform thickness on a release sheet such as a polyethylene film using a doctor blade, and the reinforcing fibers are sprayed on the surface. Thereafter, the reinforcing fibers are sandwiched with the unsaturated polyester resin composition applied to the release sheet produced in the same manner, and a sheet is formed while the unsaturated polyester resin composition is impregnated into the reinforcing fibers using a roll.

The above unsaturated polyester resin composition is used in a compression molding method, whereby a molded article is obtained. For example, a required amount of the unsaturated polyester resin composition is charged into a mold heated to 60 to 120 ° C., preferably 80 to 110 ° C., and a molding pressure of ^{2 to} 30 kg / cm ² , preferably 5 to 20 kg / cm 2 ^2. Compression molding.

If the mold temperature is lower than 60 ° C., the fluidity during compression molding may be reduced, or the molding time may be significantly increased. If the mold temperature is higher than 120 ° C., a low-cost mold cannot be used, so that the capital investment burden cannot be reduced. If the molding pressure is less than 2 kg / cm ² , the fluidity is reduced, and it may be difficult to obtain a desired molded product. If the molding pressure is more than 30 kg / cm ² , a low-cost mold cannot be used. The capital investment burden cannot be reduced.

(Function) In the present invention, when the unsaturated polyester polymer in a molten state is mixed with a polymerizable monomer to produce an unsaturated polyester resin in a high temperature state, a heating fluidizing agent is mixed. Thereby, the heating fluidizing agent can be uniformly dispersed in the unsaturated polyester resin.
Therefore, when a molded article is obtained by compression molding using the unsaturated polyester resin composition obtained in the present invention, the molded article with little performance variation can be obtained because the heating fluidizing agent is uniformly dispersed. Further, the heating fluidizer acts to enhance the wettability of the interface between the inorganic material and the resin and to improve the "slip" between the composition and the mold, thereby increasing the fluidity during low-temperature low-pressure molding. Is considered to have been greatly improved.

[0051]

Embodiments of the present invention will be described below. Example 1 An unsaturated polyester polymer composed of maleic acid, isophthalic acid and propylene glycol was introduced into a dissolving tank containing styrene and stirred to obtain an unsaturated polyester resin having a styrene content of 45% by weight. On this occasion,
Stearyl alcohol (heating fluidizer, melting point: 56 to 60 ° C.) was added in advance to a dissolving tank containing styrene so as to be 5 parts by weight based on 100 parts by weight of the unsaturated polyester resin. The unsaturated polyester polymer was introduced into the dissolving tank and stirred and mixed at the same time to obtain an unsaturated polyester resin.

25 parts by weight of a polystyrene styrene solution (styrene content: 60% by weight), 160 parts by weight of calcium carbonate (average particle size: 2 μm), 100 parts by weight of the above unsaturated polyester resin, a polymerization inhibitor 0.05 parts by weight of hydroquinone, 0.6 parts by weight of magnesium oxide, and 2,4,4-trimethylpentylperoxy 2-ethylhexanoate as an organic peroxide.
A 25 mm glass chopped strand was impregnated with an unsaturated polyester resin composition in which 25 parts by weight and 6.25 parts by weight of zinc stearate were mixed, and coated with a polyethylene film to obtain a roll-shaped SMC. This SMC is 4
Aged at 0 ° C. for 1 day.

The SMC was cut out as described below, and a flat plate die (400 mm × 150 mm × thickness 4 m) was cut by a press machine.
Using m), compression molding was performed under the conditions of 90 ° C. and 10 kg / cm ² to obtain a molded product.

Example 2 An unsaturated polyester resin composition was prepared in the same manner as in Example 1 except that glycerin monostearate (melting point: 63 to 68 ° C.) was used as a heating fluidizer instead of stearyl alcohol. Obtained and compressed in the same manner to obtain a molded product.

(Comparative Example 1) An unsaturated polyester resin composition was prepared in the same manner as in Example 1 except that stearyl alcohol was not mixed in the dissolving tank and stearyl alcohol was mixed in the paste stirring tank in the SMC production process. Get
Similarly, compression molding was performed to obtain a molded product.

Comparative Example 2 Unsaturated polyester was prepared in the same manner as in Example 2 except that glycerin monostearate was not mixed in the dissolving tank and glycerin monostearate was mixed in the paste stirring tank in the SMC production process. A resin composition was obtained and compression molded in the same manner to obtain a molded product.

(Comparative Example 3) An unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that the amount of stearyl alcohol was changed to 0.01 part by weight. Obtained.

Comparative Example 4 An unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that the amount of stearyl alcohol was changed to 30 parts by weight, and a compression molded article was obtained in the same manner. .

Comparative Example 5 An unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that stearyl alcohol was not used at all, and a compression-molded product was obtained in the same manner.

Comparative Example 6 The procedure of Example 1 was repeated, except that 5 parts by weight of a commercially available liquid viscosity reducing agent (“Superdyne V-203” manufactured by Takemoto Yushi Co., Ltd.) was used instead of stearyl alcohol. Thus, an unsaturated polyester resin composition was obtained, and compression molded in the same manner to obtain a molded product.

The unsaturated polyester resin compositions and molded articles obtained in the above Examples and Comparative Examples were evaluated as follows, and the results are shown in Table 1.

(1) Charge area ratio of molded article (%) The ratio of the projected area of the portion where the SMC was actually filled to the projected area of the portion of the flat plate mold that should come into contact with the SMC is defined as The charge area ratio was calculated and used as an index of SMC fluidity. In addition, each SMC roll (width 5
Four SMC sheets were sequentially cut out from the longitudinal direction (50 mm × thickness 3 mm), and these were subjected to compression molding four times as samples a, b, c, and d to evaluate the variation in fluidity. In addition, for charging the flat plate mold, an SMC was placed at the corner on the short side of the flat plate mold, and the charge area was set to 11%.

(2) Evaluation of Surface Properties of Molded Article The molded article was visually observed, and burrows on the surface (holes having a size of 1 mm or more appearing on the molded article surface) were evaluated according to the following evaluation criteria. A: There are no burrows B: 3 or less burrows of less than 1 to 3 mm C: There are 4 or more burrows of less than 1 to 3 mm, or 3 or more burrows.

(3) Evaluation of handleability of SMC The handleability of SMC was evaluated according to the following evaluation criteria. ：: good ×: the unsaturated polyester resin composition easily adheres to the polyethylene film, and it is difficult to peel off the film.

[0065]

[Table 1]

In Table 1, Example 1 and Comparative Example 1
Alternatively, by comparing Example 2 with Comparative Example 2,
It can be seen that the heat kneading can eliminate the variation in the fluidity of the SMC (charge area ratio of the molded body).

Further, in Example 1 of Table 1, the mixing ratio of the heating fluidizer was 5 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin, and in Comparative Examples 3 and 4, the mixing ratio of the heating fluidizer was However, because of 0.01 and 30 parts by weight, respectively, in Comparative Example 3, the charge area ratio of the molded body was low,
In addition, in Comparative Example 4, cavities occurred on the surface of the obtained molded body, whereas in Example 1, the charge area ratio was 100%.
This indicates that no burrs were generated on the surface of the molded body. Therefore, as is clear from the results of Example 1 and Comparative Examples 3 and 4, it is necessary that the heating fluidizing agent be blended in the above-described specific range with respect to 100 parts by weight of the unsaturated polyester resin. I understand.

[0068]

The unsaturated polyester resin composition of the present invention has the above-mentioned constitution, and when the heating fluidizing agent is mixed with the unsaturated polyester resin, it is heated in a melting tank in a production process of the unsaturated polyester resin in a molten state. Because of the mixing, the heating fluidizing agent can be uniformly dispersed. Therefore,
Due to the effect of the heating fluidizer, the handleability of the molding material obtained from the unsaturated polyester resin composition is increased,
Since the fluidity can be uniformly increased even at a low temperature or a low pressure, it is possible to provide a molded article having no cavities or pinholes at a low temperature or a low pressure. Further, according to the present invention, it is possible to cope with a variety of types and an increase in size of the compression molding with a small capital investment, and it is possible to expand a molding width.

Claims (1)

[Claims] An unsaturated polyester resin having an unsaturated polyester polymer content of 40 to 80% by weight by mixing an unsaturated polyester polymer in a high temperature state with a polymerizable monomer. A method for producing an unsaturated polyester resin composition, comprising mixing 0.1 to 20 parts by weight of a heating fluidizer having a melting point of 40 to 150 ° C. with 100 parts by weight of a resin.