JP2003192885A - Unsaturated polyester resin composition and molded article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an unsaturated polyester resin composition capable of increasing heat release property by high heat conductivity, having good storage property and excellent in moldability and filling property. <P>SOLUTION: This unsaturated polyester resin composition comprises 5-10 mass% unsaturated polyester, 5-10 mass% vinylester resin, 65-80 mass% hard- burned magnesia sintered at ≥1,6000°C as inorganic filler, 5-8 mass% polystyrene resin as a low shrinking agent and 3-10 mass% glass fiber as a reinforcing material. Storage property of the resin composition is improved an moldability and filling property are enhanced by using the vinylester resin. A molded article having high heat conductivity and excellent in heat release property is produced by using the hard-burned magnesia as the inorganic filler. <P>COPYRIGHT: (C)2003,JPO

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 for enclosing various coil products such as transformers, solenoids, motors and generators, and molded articles thereof.

[0002]

2. Description of the Related Art Conventionally, coil products such as transformers, solenoids, motors and generators have been encapsulated using an encapsulation molding material such as unsaturated polyester resin.

There are various cases in which a motor is enclosed, and the enclosed motor is commercially available for various purposes. For this enclosed motor, in order to further improve the efficiency of energy use in recent years. High output and miniaturization are required, and various improvements are currently being considered. In that case, it is important to take measures against the heat generated by the motor. In other words, the motor begins to generate heat from the start and gradually becomes hot, but at high temperature the output decreases and the original performance of the motor cannot be obtained, and the performance of the entire device gradually decreases. is there.

In other words, it is difficult to increase the output power and downsize the motor without taking measures against heat. Specifically, as measures against heat, the structure and shape of the motor have been studied, but in the case of an encapsulated motor, rather than changing the structure of the motor, the heat dissipation of the encapsulated molding material is improved. Things are more important. In order to improve the characteristics of the encapsulation molding material, an inorganic filler is blended. In particular, when hard-baked magnesia obtained by sintering at high temperature among magnesia (magnesium oxide) is used as an inorganic filler, high heat conductivity can be imparted to the encapsulating molding material and heat dissipation can be improved. Is something that can be done.

[0005]

However, the encapsulating molding material containing hard-burning magnesia as the inorganic filler as described above has a poor long-term storability.
In some cases, the moldability and filling properties were affected in about a week.

The present invention has been made in view of the above points, and is an unsaturated polyester resin composition which can enhance heat dissipation due to high thermal conductivity, has good storage stability, and is excellent in moldability and filling property. And its molded article.

[0007]

The unsaturated polyester resin composition according to claim 1 of the present invention contains 5 to 10% by mass of an unsaturated polyester resin and 5 parts by weight of a vinyl ester resin.
10 to 10 mass%, 65 to 80 mass% of hard-burned magnesia sintered at 1600 ° C. or more as an inorganic filler, 5 to 8 mass% of polystyrene resin as a low shrinking agent, and glass as a reinforcing material. It is characterized by containing 3 to 10% by mass of fibers.

The invention of claim 2 is characterized in that, in claim 1, the vinyl ester resin has bisphenol A as a basic skeleton.

According to a third aspect of the present invention, in the first or second aspect, the vinyl ester resin has a viscosity of 200 to 800 m.
It is characterized by being Pa · s.

The invention of claim 4 is characterized in that, in any one of claims 1 to 3, the unsaturated polyester resin is a bisphenol A resin.

A molded article according to a fifth aspect is characterized by being formed by processing the unsaturated polyester resin composition according to any one of the first to fourth aspects.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

The unsaturated polyester resin composition according to the present invention comprises an unsaturated polyester resin, a vinyl ester resin,
It contains an inorganic filler, a low-shrinking agent and a reinforcing material.

In the present invention, the unsaturated polyester resin is not particularly limited, and for example, "Yupica 7123" manufactured by Nippon Yupica Co., Ltd., "Polymer 9516" manufactured by Takeda Pharmaceutical Co., Ltd., and the like can be used.
Preferably, a bisphenol A resin is used as the unsaturated polyester resin. The bisphenol A-based resin is a resin that uses ethylene oxide or propylene oxide adduct of bisphenol A, hydrogenated bisphenol A, or the like as a glycol component, and has excellent heat resistance characteristics as compared with a normal unsaturated polyester resin. Therefore, when the bisphenol A resin is used, the above properties can be imparted to the unsaturated polyester resin composition and its molded product. Moreover, the use of the bisphenol A resin is more advantageous than the use of the usual unsaturated polyester resin, for example, the decrease in the bending strength after the molded product is treated at 200 ° C. for 24 hours is reduced.

The unsaturated polyester resin is contained in an amount of 5 to 10% by mass based on the total amount of the unsaturated polyester resin composition. If the content deviates from this range, it becomes impossible to obtain a molded product having good moldability and dimensional stability.

In the present invention, the vinyl ester resin (epoxy acrylate resin) is not particularly limited, and for example, "Neopol 8520" manufactured by Nippon Yupica Co., Ltd. can be used. By using a vinyl ester resin in this way, an unsaturated polyester resin composition having excellent storage stability can be prepared,
The fluidity of the unsaturated polyester resin composition can be increased, and the moldability and filling property can be improved.

The vinyl ester resin is contained in an amount of 5 to 10% by mass based on the total amount of the unsaturated polyester resin composition. If the content deviates from this range, it becomes impossible to obtain a molded product having good moldability and dimensional stability.

As the vinyl ester resin, it is preferable to use a bisphenol A type resin having bisphenol A as a basic skeleton. For example, the above-mentioned "Neopol 8520" manufactured by Nippon Yupica Co., Ltd. may be mentioned. Some vinyl ester resins are of novolac type, but this has a poor curing reactivity, which may cause a problem that the cycle in the molding process must be extended. However, if a bisphenol A type vinyl ester resin is used, such a problem does not occur.

The viscosity of vinyl ester resin is 200.
It is preferably ˜800 mPa · s. If the viscosity is out of this range, optimum moldability may not be obtained.

In the present invention, the inorganic filler is
Hard-burning magnesia is used. This hard-burning magnesia is obtained by crushing magnesium oxide obtained by calcining (sintering) magnesium hydroxide at a temperature of 1600 ° C. or higher,
It is obtained by sizing, and when an unsaturated polyester resin composition containing this is used, a molded product having good thermal conductivity and excellent heat dissipation can be produced. In addition to the above hard-baked magnesia, magnesite (magnesium carbonate) is used for magnesia at 800 ° C.
There is lightly burned magnesia obtained by firing before and after, but use of this is unsuitable in the present invention. That is, since hard-burned magnesia is inactive, it is most suitable as a filler, but light-burned magnesia has high surface activity and high reactivity, and is usually used as a thickener. If it is used, the unsaturated polyester resin composition will change over time and sufficient moldability cannot be obtained. As a specific example of hard-burning magnesia,
Tateho Chemical Industry Co., Ltd. "Electrical fusion magnesia K for electric heating"
"MAOH series", "Electric fused magnesia KMB for electric heating"
"O series", "high-purity electrofused magnesia / SSP series", "Chinese electrofused magnesia Mgo99" manufactured by Kaminoshima Chemical Co., Ltd., and the like. In addition, if the calcination temperature at the time of preparing hard-baked magnesia is less than 1600 ° C., the effect of increasing the thermal conductivity cannot be obtained.

Hard-baked magnesia is contained in an amount of 65 to 80% by mass based on the total amount of the unsaturated polyester resin composition. When the content is less than 65% by mass, the high thermal conductivity characteristic of hard-baked magnesia cannot be imparted to the unsaturated polyester resin composition, and the heat dissipation of the molded article cannot be enhanced. On the contrary, when the content exceeds 80 mass%, the resin component becomes relatively insufficient and the viscosity of the unsaturated polyester resin composition becomes insufficient.

The average particle size of hard-baked magnesia is 5-40.
It is preferably μm. If the average particle size is out of this range, good moldability may not be obtained. Although it is possible to use a plurality of hard-burning magnesia having different average particle sizes in combination, the average particle size of the whole is preferably within the above range.

In the present invention, the low-shrinking agent is a polystyrene resin, which is contained in an amount of 5 to 8% by mass based on the total amount of the unsaturated polyester resin composition. If the content is less than 5% by mass, the low shrinkage effect of preventing shrinkage due to curing of the unsaturated polyester resin composition cannot be sufficiently obtained, and conversely if the content exceeds 8% by mass. However, it is not possible to obtain a further low shrinkage effect, and the bending strength may decrease.

Further, in the present invention, glass fiber is used as the reinforcing material, and the glass fiber is contained in an amount of 3 to 10% by mass based on the total amount of the unsaturated polyester resin composition. When the content is less than 3% by mass, the strength of the molded product is significantly reduced. The more glass fiber is contained, the higher the strength of the molded product can be obtained. However, in the present invention, the strength of the structural application material is not required, and if the content exceeds 10% by mass, the heat of the molded product becomes high. This will reduce the conductivity. The glass fiber is not particularly limited, but the fiber length is, for example, 1.5 to 5 mm.
It is possible to use those of short fibers.

Further, an additive may be used in the present invention, and the additive may be contained in an amount of 1 to 4% by mass based on the total amount of the unsaturated polyester resin composition. The additive is not particularly limited, but for example, a releasing agent such as commonly available waxes (zinc stearate, carnauba), a pigment such as carbon black,
Curing catalysts such as organic peroxides and styrene resins ("CJ3946" and "CJ3947" manufactured by Matsushita Electric Works Ltd.)
Crosslinking agents such as

And the above unsaturated polyester resin,
An unsaturated polyester resin composition can be prepared by adding a vinyl ester resin, an inorganic filler, a low-shrinking agent and a reinforcing material to a kneader or the like and mixing them. In the unsaturated polyester resin thus obtained,
Since a part of the resin component is a vinyl ester resin, the long-term storability is good, and it is not necessary to prepare the molded product immediately before it is manufactured.

Next, various types of molded articles can be manufactured by molding the unsaturated polyester resin composition obtained as described above as an encapsulating material. For example, a coil-encapsulated molded product in which the coil is encapsulated can be manufactured by setting the coil in a transfer molding die and performing transfer molding using the above unsaturated polyester resin composition. At this time, in the unsaturated polyester resin composition, since a part of the resin component is a vinyl ester resin, the moldability and the filling property are excellent, and the molding time is shortened to improve the manufacturing efficiency of the molded product. In addition, it is possible to prevent defects such as pinholes, scrapes and welds from occurring in the molded product. The molding method is not particularly limited, and an injection molding method or a compression molding method (direct pressure molding) can also be performed.

In the molded article obtained as described above,
Since it contains a predetermined amount of hard-burned magnesia, it has good thermal conductivity and excellent heat dissipation. Therefore, for example, in a molded product in which a motor is enclosed, the heat generated by the motor can be quickly dissipated to the outside, and the deterioration of the motor performance due to heat generation can be prevented.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples.

1. Raw materials for unsaturated polyester resin composition In preparing the unsaturated polyester resin composition,
The following were used. That is, as the unsaturated polyester resin, "Polymal 9516" manufactured by Takeda Pharmaceutical Co., Ltd.
"Neopol 8520" manufactured by Nippon Yupica Co., Ltd. as a vinyl ester resin, "SSP" manufactured by Tateho Chemical Industry Co., Ltd. as an inorganic filler, and polystyrene resin "HRM-5B" manufactured by Toyo Styrene Co., Ltd. as a low-shrinking agent.
, Glass fiber “RES03” manufactured by Nippon Glass Fiber Co., Ltd. as a reinforcing material, and zinc stearate as a release agent,
Carbon black was used as a pigment, "Kayaester O-50" manufactured by Kayaku Akzo Co., Ltd. was used as a curing catalyst, and "CJ3947" manufactured by Matsushita Electric Works Ltd. was used as a crosslinking agent.

2. Preparation of Unsaturated Polyester Resin Composition and Preparation of Test Piece (1) Preparation of Unsaturated Polyester Resin Composition A predetermined amount of raw materials shown in Table 1 and Table 2 was put into a kneader, and this was heated at 25 to 30 ° C. for 20 to 20 ° C. The unsaturated polyester resin compositions of Examples 1-9 and Comparative Examples 1-6 were prepared by mixing for 40 minutes.

(2) Manufacture of test piece Mold: When making a test piece for measuring thermal conductivity, a disk mold of 100φ × 25 mm was used, and a test piece for measuring bending strength was prepared. In doing so, a die for direct pressure molding was used.

Molding conditions: Mold temperature is 150 to 160
℃, curing time is the maximum wall thickness of the test piece × 20-30 seconds / mm
Set to.

Molding pressure: 9.8 to 14.7 Pa.

3. Characteristic evaluation (1) Thermal conductivity The thermal conductivity was measured according to JIS K6911.

(2) Bending strength The bending strength was measured according to JIS K6911.

(3) Moldability The moldability was evaluated by using a mold conforming to the ASTM method and measuring the spiral flow under the following conditions.

Mold temperature: 150 ° C. Injection pressure: 4.9 MPa Injection time: 30 seconds Curing time: 90 seconds (4) Storability The storage stability was evaluated at a temperature of 35 ° C. of 80% or more of the initial spiral flow value. Was measured by measuring the period of holding.

(5) Filling property The filling property was evaluated by producing a coil-encapsulated molded product using a mold for coil encapsulation and observing this molded product. The criteria for judgment are as follows.

[0040] "○": No pinholes, scrapes, welds, etc. “×”: There are pinholes, scrapes, welds, etc. The results of the above characteristic evaluation are shown in Tables 1 and 2.

[0041]

[Table 1]

[0042]

[Table 2]

As shown in Table 1, it is confirmed that all of Examples 1 to 9 have high thermal conductivity, good storage stability, and excellent moldability and filling property.

On the other hand, as shown in Table 2, in Comparative Examples 1 to 6, although the same raw materials as in Examples 1 to 9 were used, the content of each raw material was too small or too large. It is confirmed that the thermal conductivity, the storage stability, the moldability and the filling property cannot be improved at the same time due to the excess.

[0045]

As described above, the unsaturated polyester resin composition according to claim 1 of the present invention contains 5 to 10% by mass of the unsaturated polyester resin and 5 to 5% of the vinyl ester resin.
10 mass% contained, hard burned magnesia sintered at 1600 ° C. or higher as an inorganic filler contained 65-80 mass%,
Since it contains 5 to 8 mass% of polystyrene resin as a low-shrinking agent and 3 to 10 mass% of glass fiber as a reinforcing material, the vinyl ester resin is used as a part of the resin component to improve the storability. It is possible to obtain high moldability and filling property at the time of molding, and by using hard-burning magnesia as an inorganic filler, it is possible to manufacture a molded product with high heat conductivity and excellent heat dissipation. Is what you can do. Moreover, by using polystyrene resin as the low-shrinking agent, curing shrinkage can be prevented, and by using glass fiber as the reinforcing material, the strength of the molded product can be increased.

Further, in the invention of claim 2, since the vinyl ester resin has bisphenol A as a basic skeleton, it has a higher curing reactivity than the novolac type vinyl ester resin and shortens the cycle of molding process. Is something that can be done.

Further, according to the third aspect of the invention, since the viscosity of the vinyl ester resin is 200 to 800 mPa · s, the moldability can be further enhanced.

In the invention of claim 4, since the unsaturated polyester resin is a bisphenol A-based resin, heat resistance can be imparted to the unsaturated polyester resin composition or a molded product thereof. For example, a molded product. At 200 ° C for 2
It is possible to reduce the decrease in bending strength after the treatment for 4 hours.

Since the molded article according to claim 5 is formed by processing the unsaturated polyester resin composition according to any one of claims 1 to 4, the thermal conductivity is improved by the hard-burning magnesia, and It is possible to improve radiation.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 63/10 C08L 63/10

Claims (5)

[Claims] 1. Hard-burning magnesia containing 5 to 10% by mass of an unsaturated polyester resin, 5 to 10% by mass of a vinyl ester resin, and 65 to 80% by mass of hard-burned magnesia sintered at 1600 ° C. or higher as an inorganic filler. %, The polystyrene resin is contained as a low-shrinking agent in an amount of 5 to 8% by mass, and the glass fiber is contained in an amount of 3 to 10% by mass as a reinforcing material. 2. The vinyl ester resin is bisphenol A.
2. The basic structure of claim 1
The unsaturated polyester resin composition described in 1. 3. The vinyl ester resin has a viscosity of 200 to 8
It is 00 mPa * s, The claim 1 or 2 characterized by the above-mentioned.
The unsaturated polyester resin composition described in 1. 4. The unsaturated polyester resin composition according to claim 1, wherein the unsaturated polyester resin is a bisphenol A resin. 5. A molded article obtained by molding the unsaturated polyester resin composition according to any one of claims 1 to 4.