JP2531892B2 - Unsaturated polyester resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to unsaturated polyester resin compositions. More specifically, surface smoothness (= leveling), surface gloss, other surface characteristics,
The present invention relates to an unsaturated polyester resin composition which gives a molded article excellent in appearance.

[0002]

2. Description of the Related Art An unsaturated polyester resin composition represented by a bulk molding compound (hereinafter abbreviated as BMC) and a sheet molding compound (hereinafter abbreviated as SMC) is a glass fiber reinforced plastic.
In addition to strength characteristics (hereinafter abbreviated as FRP), combined use of a thermoplastic resin provides unique characteristics such as low shrinkage and no shrinkage, which are not found in other molding materials, and dramatically improved moldability. As a result, BMC is used in OA equipment chassis, audio / video related parts, automobile headlamp reflectors, and other fields that require severe dimensional accuracy and heat resistance. SMC has excellent leveling and strength characteristics for automobiles. It has been expanding its applications, centering on outer panel parts for housing and parts related to water supply for residential equipment. In particular, BMC behaves like a liquid with an extremely low viscosity when flowing in the mold, has a small pressure loss and a small residual strain, but in order to obtain its original excellent moldability, pay attention to the mold alignment accuracy when designing the mold. It is necessary to suppress the flow of burrs from the material side as well as various other improvements in formability.

[0003] For example, it is empirically known that burr outflow is suppressed by using calcium carbonate and other fillers having coarse particles, but leveling of the molding surface and deterioration of other surface characteristics cannot be avoided. There was a problem.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an unsaturated polyester resin which gives a molded article excellent in surface properties such as leveling and surface gloss due to the combined use of a specific filler. To provide a composition.

[0005]

The inventors of the present invention have made various studies in order to solve the above-mentioned problems, and in the process, a specific filler and the filler as a constituent component thereof are used. The present invention has been completed by focusing on the point that the linear expansion coefficient of the molded product formed from the unsaturated polyester resin composition contained is closely related to leveling, surface gloss, other molding appearance, and surface characteristics. .

That is, in the present invention, the average particle size is 5 to 1
It is an unsaturated polyester resin composition containing 5 to 30% by weight of a filler of 00μ, and the linear expansion coefficient of the filler is ± 0 of the linear expansion coefficient of a molded product formed from the unsaturated polyester resin composition. It relates to an unsaturated polyester resin composition characterized by having a concentration of 3 × 10 ⁻⁵ / ° C. The present invention provides an unsaturated polyester resin composition that can achieve the above object.

The unsaturated polyester resin used for preparing the unsaturated polyester resin composition of the present invention is an unsaturated dibasic acid such as fumaric acid or maleic anhydride or its acid anhydride and terephthalic acid or isophthalic acid. acid,
An unsaturated polyester having an acid value of 10 to 30 obtained by esterifying a saturated dibasic acid such as phthalic anhydride or an acid anhydride thereof with a polyhydric alcohol such as propylene glycol, hydrogenated bisphenol A and neopentyl glycol is prepared. It is obtained by dissolving it in a crosslinkable monomer. Examples of the crosslinkable monomer include styrene, divinylbenzene, diallyl phthalate, diallyl terephthalate, and esters of acrylic acid or methacrylic acid. The amount of the crosslinkable monomer to be blended is in the range of 25 to 70 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the unsaturated polyester resin.

The average particle size used in the present invention is 5-10.
As the 0μ filler, there are SMC molded products represented by bathtubs, BMC molded products represented by headlamp reflectors, and other FRPs pulverized by a granulator, grinder, jet mill, or other pulverizer. As an example. The average particle size of the filler is 10
If it exceeds 0μ, leveling occurs on the surface of the molded product, and unevenness that impairs the appearance occurs. Conversely, if the average particle size is less than 5μ, there is no effect that should be seen in leveling, surface gloss, and other surface characteristics, rather the viscosity of the resin composition And the tendency to impair the formability is observed.

The coefficient of linear expansion of the filler is ± 0.3 of the coefficient of linear expansion of a molded product formed from an unsaturated polyester resin composition containing a filler having an average particle size of 5 to 100 μm.
It is necessary to be × 10 ^-5 / ° C. If the linear expansion coefficient of the filler is out of the range of ± 0.3 × 10 ⁻⁵ / ° C. of the molded product formed from the unsaturated polyester resin composition, the surface of the molded product is leveled and the appearance is deteriorated. Unevenness occurs, and the effect of the present invention cannot be obtained.

The filler is added in the range of 5 to 30% by weight in the unsaturated polyester resin composition. If the addition amount of the filler is less than 5% by weight, the effect of the present invention cannot be obtained, while 3
If it exceeds 0% by weight, the fluidity of the material at the time of molding decreases, resulting in impairing the moldability, and unavoidable deterioration of leveling, surface gloss, and other molding appearance.

The filler used in the present invention is especially SMC.
The range is not limited to molded products, BMC molded products, and other crushed products of FRP. The combination of other fillers is not particularly limited as long as it is usually used for BMC and SMC, and calcium carbonate, aluminum hydroxide, barium sulfate, clay, talc, etc. are appropriately used. It doesn't matter.

The unsaturated polyester resin composition of the present invention contains, in addition to the above-mentioned filler, a low-shrinking agent of a publicly known thermoplastic resin typified by polystyrene, and an internal release agent such as zinc stearate, Additives generally used in unsaturated polyester resin compositions, such as curing agents such as benzoyl peroxide and t-butyl peroxybenzoate, glass fibers and other reinforcing materials, colorants, thickeners, etc. within the range that does not impair the effects of the present invention. You may mix in.

[0013]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples.

Reference Example 1 A BMC headlamp reflector was crushed and then crushed with an HM-23 type crusher (screen diameter = 3 mm) manufactured by Orient Co., Ltd. to obtain a filler (filler) A having an average particle diameter of 80 μm. It was made. Further, the filler A is pulverized by a single track jet mill, STJ-200, manufactured by Seishin Enterprise Co., Ltd., and the particle size is adjusted according to the processing conditions. A filler B having an average particle size of 40 μ and a filler C having an average particle size of 3 μ are prepared. Obtained. The average particle size was measured by a light diffraction scattering method particle size distribution measuring device, PRO-7000 manufactured by Seishin Enterprise. For linear expansion coefficient, cut out the test piece from the headlamp reflector,
It measured in the temperature range of 20-80 degreeC. As a result, the coefficient of linear expansion was 2.6 × 10 ⁻⁵ / ° C.

Reference Example 2 After crushing an SMC bathtub, Orient Co., Ltd., HM-
A filler D having an average particle diameter of 120 µ was prepared by pulverizing with a 23-type pulverizer (screen diameter = 3 mm), and the filler D was further pulverized with a single track jet mill, STJ-200 to obtain a filler E having an average particle diameter of 8 µ. Got The test piece was cut out from the bathtub and the linear expansion coefficient measured in the temperature range of 20 to 80 ° C was 2.0 x 10 ^-5 / ° C.

Examples 1 to 7 With respect to the blended composition shown in Table 1, each component was kneaded using a double-arm type kneader to prepare 7 kinds of BMC. Test box with the shape shown in Fig. 1 and Fig. 2 at each BMC
(360 x 120 x 25 mm high, 3 mm thick) using a 300 ton injection molding machine, molding temperature = 160 ° C, injection pressure = 3
Molded under the conditions of 00 kg / cm ² and molding time = 2 minutes
(Leveling, surface gloss) was visually evaluated. The evaluation results of each composition are shown in Table 1 together with the particle size of fillers A to E, the linear expansion coefficient, the addition amount, and the linear expansion coefficient and shrinkage rate of the BMC molded product.

[0017]

[Table 1]

Comparative Examples 1 to 7 Regarding the blending composition shown in Table 2, the respective components were kneaded using a double-arm kneader to prepare 7 kinds of BMC. A test box was molded under the same conditions as in Examples 1 to 7, and the molding appearance (leveling, surface gloss) was visually evaluated. The evaluation results of each composition are the particle size of the fillers A to E, the linear expansion coefficient,
Table 2 shows the addition amount, the linear expansion coefficient of the BMC molded product, and the shrinkage ratio together.

[0019]

[Table 2]

As shown in the evaluation of Examples 1 to 7 in Table 1,
All of the BMC molded products produced according to the present invention showed clear improvements in leveling and gloss as compared with the molded product of Comparative Example 1 of Table 2 in which the filler specified in the present invention was not added. It was On the other hand, in Comparative Examples 2 to 7 in Table 2, good leveling and gloss results were not obtained.

Examples 8 to 10 With respect to the compounding compositions shown in Table 3, sheets were prepared by impregnating 1-inch-long glass fibers uniformly dispersed with a resin mixture prepared by mixing other components except glass fibers with a high-speed mixer. Three types of SMC with the shape of a circle were prepared. Using a 100 ton compression molding machine, molding temperature = 135-145 ° C., molding pressure = 80 kg / c
m ^2, box-shaped test mold at molding time = 5 minutes Conditions (360
Molding was performed with a height of 240 mm × 240 mm and a thickness of 3 mm, and the molding appearance (leveling, surface gloss) was visually evaluated. The evaluation results of the respective formulations are shown by the particle size of the fillers A to E, the linear expansion coefficient,
Table 3 shows the addition amount, the linear expansion coefficient of the SMC molded product, and the shrinkage ratio together.

Comparative Examples 8 to 9 Sheets were prepared by impregnating 1-inch-long glass fibers uniformly dispersed with a resin mixture prepared by mixing other components except glass fibers with a high-speed mixer. Two types of SMC with a shape of squirrel were prepared. A box-shaped test mold was molded under the same conditions as in Examples 8 to 10, and the molding appearance (leveling, surface gloss) was visually evaluated. The evaluation results of each composition are the particle size of the fillers A to E, the linear expansion coefficient, the addition amount and the SM.
Table 3 also shows the linear expansion coefficient and the shrinkage rate of the C molded product.

[0023]

[Table 3]

As shown in the evaluation of Table 3, even in SMC formulation, Examples 8 to 10 have leveling and surface gloss in comparison with Comparative Examples 8 and 9 in which the filler specified in the present invention is not added. The clear improvement was observed.

[0025]

As is apparent from the above description, the unsaturated polyester resin composition of the present invention is excellent in leveling, surface gloss, and other molding appearance due to the combined use of a specific filler, and therefore the electric / electronic industry. , As an unsaturated polyester resin composition useful in the automobile industry, housing applications, etc.,
It can be used widely.

[Brief description of drawings]

FIG. 1 is a plan view of a test box used for a test.

FIG. 2 is a sectional view taken along the line AA ′ in FIG.

Claims (1)

(57) [Claims] 1. A filler having an average particle size of 5 to 100 .mu.
To 30 wt% of the unsaturated polyester resin composition, and the linear expansion coefficient of the filler is ± 0.3 × 10 ⁻⁵ of the linear expansion coefficient of the molded product formed from the unsaturated polyester resin composition. / ° C. An unsaturated polyester resin composition, characterized in that