JP2000234050A - Unsaturated polyester resin molding material and molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an unsaturated polyester resin molding material which prevents a power output decrease of a motor by promoting the release of heat, generated from the motor coil, to the outside of the motor. SOLUTION: This molding material contains 10 to 20 wt.% unsaturated polyester resin, 0.1 to 0.5 wt.% hardener, 3 to 10 wt.% glass fiber and 70 to 80 wt.% inorganic filler. A globular crystalline silica is used as the inorganic filler. The material yields an improved thermal conductivity compared to the conventional molding materials wherein aluminum hydroxide or calcium carbonate was contained as inorganic fillers.

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 molding material used mainly for enclosing a motor.

[0002]

2. Description of the Related Art In recent years, due to consideration for the global environment, the automobile industry has been developing clean electric vehicles and hybrid cars that emit no or little exhaust gas, and commercial vehicles are also sold by various manufacturers. Is being done. Although these clean vehicles use a motor as a power source instead of a conventional internal combustion engine, motors for vehicles are larger and have higher output than motors used in ordinary home appliances such as washing machines. Therefore, in order to ensure quietness and to prevent the reliability of operation from being reduced due to vibration, a motor is sealed with a molding material containing a resin.

[0003]

However, when the motor is sealed with a molding material, it is difficult to dissipate the heat generated from the coil of the motor to the outside, and there is a fear that the temperature of the motor increases and the output decreases. Therefore, conventionally, it has been attempted to improve the thermal conductivity of the molding material by adding an inorganic filler (having an irregular shape and an average particle size of 5 to 30 μm) such as aluminum hydroxide or calcium carbonate to the molding material. Sufficient heat radiation could not be obtained.

[0004] The present invention has been made in view of the above points, and is an unsaturated polyester resin molding material capable of easily radiating heat generated from a coil of a motor to the outside and preventing a decrease in output of the motor. The purpose is to provide.

[0005]

The unsaturated polyester resin molding material according to claim 1 of the present invention comprises 10 to 20% by weight.
Unsaturated polyester resin, 0.1 to 0.5% by weight of a curing agent, 3 to 10% by weight of glass fiber, 70 to 80%
It is characterized by containing an inorganic filler by weight and using substantially spherical crystalline silica as the inorganic filler.

The unsaturated polyester resin molding material according to claim 2 of the present invention is characterized in that, in addition to the constitution of claim 1, substantially spherical crystalline silica is added in an amount of 50% by weight based on the total amount of the inorganic filler.
It is characterized by using the above.

The unsaturated polyester resin molding material according to claim 3 of the present invention is characterized in that, in addition to the constitution of claim 1 or 2, the average particle size of the substantially spherical crystalline silica is 15 to 50 μm. Is what you do.

A molded article according to a fourth aspect of the present invention is characterized by being formed by molding the unsaturated polyester resin molding material according to any one of the first to third aspects.

[0009]

Embodiments of the present invention will be described below.

The unsaturated polyester resin is prepared by subjecting a dibasic acid and a dihydric alcohol to a condensation reaction to produce an unsaturated polyester, and mixing the unsaturated polyester with a vinyl monomer (reactive diluent) to prepare a liquid resin. The general ones given can be used in general. Examples of the dibasic acid include maleic anhydride, fumaric acid, adipic acid, phthalic anhydride, isophthalic acid, tetrachlorophthalic anhydride, hetic acid, nadic anhydride and the like. Examples of the dihydric alcohol include ethylene glycol, propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, and bisphenoldioxyethyl ether. Examples of the vinyl monomer include styrene, ortho-chlorostyrene, diallyl phthalate, triallyl isocyanurate, methyl methacrylate, and diallyl benzene phosphonate. Specific products of unsaturated polyester resins include POLYDAR 9516 manufactured by Takeda Pharmaceutical Co., Ltd.
And Yupika 123 manufactured by Japan Yupika Co., Ltd. can be exemplified.

As the curing agent (polymerization initiator), various peroxides can be used alone or in combination of two or more. Specifically, t-Butyl peroxy benzonete (for example, Perbutyl Z manufactured by NOF Corporation) and 1,1-Bis (t-butyl pe
(roxy) -3,3,5-trimethylcyclohexane (for example, Perhexa 3M manufactured by NOF Corporation) or the like can be used. As the glass fiber, those conventionally used in molding materials which have been sold in Japan or overseas can be used. For example, those sold by Nippon Glass Fiber Co., Ltd., Electric Glass Co., Ltd., Central Glass Co., Ltd. and the like can be used. Preferably, a glass chop having a fiber length of about 0.1 to 5 mm is used in consideration of dispersibility in a molding material.

In the present invention, substantially spherical crystalline silica is used as the inorganic filler. Substantially spherical crystalline silica is crystalline silica in which the difference between the major axis and the minor axis is 0 to 5 μm (0 μm is spherical and those within 5 μm are approximately spherical), and a natural ingot of silica is collected from the mine. This is obtained by crushing and classifying to obtain crushed crystalline silica, further crushing the crushed crystalline silica with a crushing tool such as a ball mill, and then classifying it. Specifically, Quartz Grain QG10 or Quartz Grain QG35 manufactured by Kyushu Ceramics Co., Ltd. can be used.

In the present invention, the above-mentioned crushed crystalline silica can be used in combination as an inorganic filler. Specifically, crystallite 3K or crystallite CMC-12 manufactured by Tatsumori Corporation can be used. When substantially spherical crystalline silica and crushed crystalline silica are used together as the inorganic filler, it is preferable to use the substantially spherical crystalline silica in an amount of 50% by weight or more based on the total amount of the inorganic filler. If the substantially spherical crystalline silica is less than 50% by weight based on the total amount of the inorganic filler, abrasion of a kneader or a molding machine for kneading the molding material, a molding die, or the like may be increased. Of course, all (100% by weight) of the inorganic filler may be composed of substantially spherical crystalline silica. The average particle size (average of major axis) of each of the substantially spherical crystalline silica and the crushed crystalline silica is 15
It is preferably from 50 μm to 50 μm. If the average particle diameter of the substantially spherical crystalline silica and the crushed crystalline silica is less than 15 μm or more than 50 μm, the fluidity of the molding material may be impaired, and the moldability may be reduced. The particle size of the crystalline silica can be measured by an SK laser method (wet method) or the like.

The above-mentioned unsaturated polyester resin, curing agent, glass fiber, inorganic filler, release agent such as wax and other additives such as pigment are heated at room temperature or 30 to 60 ° C. by a kneader or the like. By mixing uniformly, the unsaturated polyester resin molding material of the present invention can be prepared. This unsaturated polyester resin molding material contains 10 to 10
It is preferred to contain 20% by weight. If the content of the unsaturated polyester resin is less than 10% by weight, the resin content may be insufficient to obtain sufficient moldability (flowability). If the content of the unsaturated polyester resin exceeds 20% by weight, the resin If the amount is excessive, the viscosity of the entire molding material may be reduced and moldability may be impaired.

The unsaturated polyester resin molding material preferably contains a curing agent in an amount of 0.1 to 0.5% by weight based on the total amount. When the content of the curing agent is less than 0.1% by weight, a sufficient curing reaction of the unsaturated polyester resin cannot be obtained, and the strength may be reduced due to insufficient curing. If it exceeds 5% by weight, the curing behavior of the unsaturated polyester resin becomes too sensitive, which may cause deterioration of the storage stability of the molding material and the appearance of the molded product. Further, the unsaturated polyester resin molding material preferably contains glass fiber in an amount of 3 to 10% by weight based on the total amount. If the glass fiber content is less than 3% by weight, the reinforcing effect of the molded article is not sufficiently generated, and the strength may be reduced. If the glass fiber content exceeds 10% by weight, the molding material May cause a reduction in the moldability of the resin.

The unsaturated polyester resin molding material preferably contains an inorganic filler in an amount of 70 to 80% by weight based on the total amount. If the content of the inorganic filler is less than 70% by weight, it is not possible to obtain a molding material and a molded article having high thermal conductivity, which is the object of the present invention, and the content of the inorganic filler is not more than 80%.
If the content is more than 10% by weight, there is a possibility that an organic component (a resin component or the like) becomes insufficient and the moldability of the molding material is reduced.

The molded article of the present invention is prepared by injecting the above-mentioned unsaturated polyester resin molding material into a heated mold, at a temperature of 120 to 170 ° C. for a time of 10 to 30 seconds (per 1 mm of molded article thickness). And can be obtained by heat curing.

Since the unsaturated polyester resin molding material and molded article of the present invention contain substantially spherical crystalline silica as an inorganic filler, the thermal conductivity becomes 1.5 W / mK or more and has high thermal conductivity. When used as an encapsulating material for a motor, silentness and reliability can be ensured without impairing heat dissipation. In addition, since it is substantially spherical crystalline silica, abrasion hardly occurs in a kneader or a mold.

[0019]

The present invention will be described below in detail with reference to examples.

Examples 1 to 9 and Comparative Examples Unsaturated polyester resin, hardener, glass fiber, inorganic filler, and other additives (release agent and pigment) in the amounts shown in Table 1
Was kneaded with a kneader at a temperature of 40 ° C. for 30 minutes to obtain an unsaturated polyester resin molding material. The following materials were used.

Unsaturated polyester resin: POLYDAR 9516 manufactured by Takeda Pharmaceutical Co., Ltd. Curing agent: organic peroxide (t-aluminoperoxy-2-ethylhexanoate) manufactured by Kayaku Akzo Co., Ltd. Glass fiber: RES03BM9 manufactured by Nippon Glass Fiber Co., Ltd. Approximately spherical crystalline silica: quartz grain manufactured by Kyushu Ceramics Co., Ltd. Crushed crystalline silica: crystallite manufactured by Tatsumori Co., and using Examples 1 to 9 and Comparative Examples The following tests were conducted.

(1) Measurement of thermal conductivity The thickness was 30 by direct pressure molding (temperature: 150 ° C., pressure: 50 Pa).
mm test piece, and the JIS K
It was measured according to 6911.

(2) Measurement of Formability A spiral flow mold 2 having a spiral groove 1 on its surface as shown in FIG. 1 was used. The width dimension of the groove 1 is 3 mm, the maximum depth of the groove 1 is 2 mm, and the maximum length of the groove 1 is 1000 m
m, the distance between adjacent grooves 1 is 1.5 mm, and the inner end of the groove in the center of the mold 2 is formed as a cull portion 3. Then, the examples 1 to 9 and the comparative example are injected into the groove 1 from the cull part 3 in the manner of transfer molding (temperature: 150 ° C., pressure: 70 Pa). The distance was measured.

(3) Measurement of die wear The aluminum orifice was attached to the pot portion of the 30T plunger transfer molding machine, and the orifices were used in Examples 1 to 9 and Comparative Examples 10 to 30 g / shot.
The weight loss of the orifice after passing through 0 shots was measured.

The results are shown in Table 1.

[0026]

[Table 1]

As is apparent from Table 1, Examples 1 to 9 using crystalline silica had higher thermal conductivity than Comparative Examples using aluminum hydroxide. In Example 7, in which crushed crystalline silica was used in an amount of 50% by weight or more, the abrasion of the mold was increased as compared with the other examples. Example 8 using substantially spherical crystalline silica having an average particle size of less than 15 μm
9 using crushed crystalline silica having an average particle size of 50 μm or more and moldability (flowability) more than the other examples
, But the moldability was higher than that of the comparative example.

[0028]

As described above, the invention of claim 1 of the present invention comprises 10 to 20% by weight of an unsaturated polyester resin,
0.1 to 0.5% by weight of a curing agent, 3 to 10% by weight of glass fiber, and 70 to 80% by weight of an inorganic filler,
Since substantially spherical crystalline silica is used as the inorganic filler, the thermal conductivity can be improved as compared with the conventional molding material containing an inorganic filler such as aluminum hydroxide or calcium carbonate. By encapsulating, the heat generated from the coil of the motor can be easily radiated to the outside, so that a decrease in the output of the motor can be prevented.

In the invention of claim 2 of the present invention, since substantially spherical crystalline silica is used in an amount of 50% by weight or more based on the total amount of the inorganic filler, it is used for molding a kneader used for kneading or a molded product. The friction with the mold can be reduced, and the wear of the kneader and the mold can be reduced.

According to the invention of claim 3 of the present invention, the substantially spherical crystalline silica has an average particle size of 15 to 50 μm, so that the flowability can be prevented from being lowered, and the moldability can be improved. You can do it.

The invention of claim 4 of the present invention provides the method of claim 1
Since the unsaturated polyester resin molding material according to any one of (1) to (3) is molded, by enclosing the motor, heat generated from the coil of the motor can be easily radiated to the outside to prevent a decrease in the output of the motor. Can be done.

[Brief description of the drawings]

FIG. 1 shows a mold used for measuring moldability according to the present invention, wherein (a) is a plan view and (b) is a cross-sectional view taken along line AA of (a).

Claims (4)

[Claims] 1. 10 to 20% by weight of an unsaturated polyester resin, 0.1 to 0.5% by weight of a curing agent, 3 to 10% by weight of glass fiber, and 70 to 80% by weight of an inorganic filler. And a substantially spherical crystalline silica as an inorganic filler. 2. The unsaturated polyester resin molding material according to claim 1, wherein substantially spherical crystalline silica is used in an amount of 50% by weight or more based on the total amount of the inorganic filler. 3. The substantially spherical crystalline silica has an average particle size of 15 to 15.
The unsaturated polyester resin molding material according to claim 1 or 2, wherein the thickness is 50 µm. 4. A molded article obtained by molding the unsaturated polyester resin molding material according to claim 1.