JP2002020602A - Molding material for low-pressure sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding material for low-pressure sealing capable of giving a molded article improved in heat cycle properties. SOLUTION: This molding material is prepared by compounding 100 pts.mass resin component comprising an unsaturated polyester resin and a diallyl phthalate resin in a mass ratio of (99/1)-(70/30) with 5-25 pts.mass silicone rubber and 70-180 pts.mass glass fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material for low-pressure sealing, and more particularly to a molding material for low-pressure sealing capable of obtaining a molded article having improved heat cycle properties.

[0002]

2. Description of the Related Art In recent years, electronic components such as capacitors, coils, and resistors have been packaged with a sealing resin in order to improve reliability and productivity. The performance required of these encapsulating resins varies depending on the form and size of the electronic components, but it has high moisture resistance, low stress, high thermal conductivity, impact resistance, etc., and satisfies these required performances. Unsaturated polyester resins have been used as resins to be used.

However, a molding material made of an unsaturated polyester resin generally tends to have a large coefficient of thermal expansion, and generates a large stress due to a difference in the coefficient of thermal expansion from a sealed component during a heat cycle. There has been a problem of causing deformation and cracking of the molded product, and there has been a demand for a molding material for sealing with further improved heat cycleability.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-pressure molding material capable of overcoming the drawbacks of the conventional sealing resin and obtaining a molded product having improved heat cycle properties. It was made for the purpose of.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, a glass composition was added to a resin component in which an unsaturated polyester resin and a diallyl phthalate resin were mixed at a specific ratio. The present inventors have found that the above object can be achieved by blending a fiber and silicone rubber, and have accomplished the present invention.

That is, the molding material for low-pressure sealing of the present invention comprises a unsaturated polyester resin and a diallyl phthalate resin in a mass ratio of 99/1 to 70/30, preferably 95/5 to 95/30.
For 100 parts by mass of the resin component blended at 75/25,
5 to 25 parts by mass of silicone rubber and 70 to 1 of glass fiber
It is characterized by containing 80 parts by mass, and the silicone rubber preferably has an average particle size of 0.1 to 5 μm.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The unsaturated polyester resin in the present invention is not particularly limited as long as it is a polycondensation of a polyhydric alcohol, an unsaturated polybasic acid and a saturated dibasic acid.

Examples of polyhydric alcohols include ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol,
Examples thereof include triethylene glycol, pentanediol, hexanediol, neopentyl glycol, hydrogenated bisphenol A, bisphenol A, and glycerin.

The unsaturated polybasic acids include, for example, maleic anhydride, fumaric acid, citraconic acid, itaconic acid and the like, and the saturated dibasic acids include, for example, orthophthalic acid, isophthalic acid, terephthalic acid, adipic acid And tetrahydrophthalic anhydride, sebacic acid, succinic acid, tetrachlorophthalic anhydride and the like. Of these, resins using terephthalic acid and isophthalic acid are preferable.

The diallyl phthalate resin in the present invention is not particularly limited, and examples thereof include diallyl isophthalate resin, diallyl orthophthalate resin, diallyl terephthalate resin and modified resins thereof, and these may be used alone or in combination of two or more. used.

In the present invention, an unsaturated polyester resin and a diallyl phthalate resin are used as resin components in a mass ratio of 9%.
9/1 to 70/30, preferably 95/5 to 75
/ 25. If the ratio of the diallyl phthalate resin in the resin component is less than this range, the heat resistance is reduced, so that the molded product is easily cracked during a heat cycle, and if the ratio exceeds this range, the fluidity during molding is increased. , The unfilled portion is likely to be generated, and the heat cycle property is deteriorated.

The silicone rubber used in the present invention is not particularly limited, and has a main chain composed of a siloxane bond and a side chain having an organic substituent such as a methyl group, a phenyl group or a vinyl group on its side chain. What is necessary is just a thing which has a shape-like polymer as a main component, and specifically, methyl silicone rubber, methyl phenyl silicone rubber, methyl vinyl silicone rubber, etc. are mentioned. Further, the side chain may be substituted with an epoxy group, an amino group, a mercapto group, or the like.

The average particle size of the silicone rubber is from 0.1 to
Preferably it is 5 μm. When the average particle size is larger than 5 μm, the sea-island effect cannot be obtained, the mechanical strength is reduced, and the heat cycle property tends not to be improved.

The silicone rubber is blended in an amount of 5 to 25 parts by mass with respect to 100 parts by mass of the resin component.
To 20 parts by mass. If the silicone rubber is less than 5 parts by mass, the toughness is reduced, and if the silicone rubber is more than 25 parts by mass, the coefficient of linear expansion is increased, and the molded product is easily cracked.

The glass fiber used in the present invention is generally cut into a predetermined length for reinforcing a resin molding material, and has a fiber diameter of 3 to 15 μm and a fiber length of 0.3 to 30 μm.
6 mm is preferred.

In the present invention, it is necessary to mix the glass fiber at a ratio of 75 to 180 parts by mass with respect to 100 parts by mass of the resin component.
The range is 150 parts by mass. If this amount is less than 75 parts by mass, sufficient mechanical strength and heat resistance cannot be obtained.
If the amount exceeds 80 parts by mass, it becomes difficult to produce a molding material, and the moldability also deteriorates.

Examples of the curing catalyst used as a curing agent for the resin component include dialkyl peroxides such as di-tert-butyl peroxide and dicumyl peroxide, diaryl peroxides, and te.
Peroxyesters such as rt-butyl-peroxybenzoate, tert-butyl-peroxy-isopropylcarbonate peroxide, 1,1-di-t
peroxyketals such as tert-butyl-peroxy-cyclohexane, benzoyl peroxide,
Examples thereof include dialloyl peroxides such as 2,4-dichlorobenzoin peroxide, diacyl peroxides, hydroperoxides such as hydroperoxide, and azo compounds such as azobisisobutyronitrile.

The curing catalyst is preferably used in an amount of 1 to 10 parts by mass, more preferably 3 to 10 parts by mass, per 100 parts by mass of the resin component.
-7 parts by mass. If the amount is less than 1 part by mass, the curing rate tends to be low, and the moldability tends to be poor. If the amount exceeds 10 parts by mass, the mechanical strength tends to decrease.

The molding material of the present invention may use a filler in addition to the basic composition described above. Examples of the filler include silica, mica, alumina, quartz glass, calcium carbonate, aluminum hydroxide, and clay. And the like. Preferred examples thereof include one or a mixture of two or more.

The molding material of the present invention is produced by a pressure kneader, a twin screw extruder, a Henschel mixer, a mixing hot roll or the like. The molding method for obtaining a molded article from the molding material of the present invention may be any of known molding methods, for example, injection molding, transfer molding, compression molding, etc., but is particularly suitable for injection molding with excellent productivity. .

[0021]

The present invention will be described in more detail with reference to the following examples. In addition, the performance of the obtained molding material was evaluated according to the following method.

(1) Spiral flow According to the EMMI method, a molding temperature of 150 ° C. and a molding pressure of 6.
It was measured under the condition of 9 MPa.

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

(3) Charpy Impact Strength Charpy impact strength was measured according to JIS K6911.

(4) Heat cyclability The dimensions are 17 mm × 12 mm × 1 with an iron core inserted.
Using a model for evaluation having a thickness of 0 mm and a resin thickness of 0.5 mm, a heat cycle test in which -20 ° C. × 30 minutes to 120 ° C. × 30 minutes is one cycle was performed 100 times, and the occurrence of cracks was observed.

Example 1 Terephthalic acid-based unsaturated polyester resin [Yupika 8523, manufactured by Nippon Yupika Co., Ltd.] 9
0 parts by mass, 10 parts by mass of diallyl orthophthalate resin [DAPK, manufactured by Daiso Corporation], silicone rubber [Trefle E6 manufactured by Dow Corning Silicone Toray, Inc.]
00 (average particle diameter 2 μm)], 10 parts by mass, 88 parts by mass of glass fiber [Fibre diameter 10 μm, manufactured by NEC Corporation] surface-treated with a silane coupling agent, 5 parts by mass of silica, tert-butyl peroxide After blending 5 parts by mass of benzoate and kneading with a mixing hot roll,
It was pulverized with a power mill to produce a molding material.

The obtained molding material was injection-molded under the following conditions: cylinder temperature: front part 90 ° C., rear part 50 ° C., mold temperature: 160 ° C., curing time: 120 seconds, and JIS bending test piece (80 × 10 ×) 4mm), JIS impact test piece (90 × 1
5 × 15 mm). About the obtained test piece,
Flexural strength and Charpy impact strength were measured.

Further, the molding material was transfer-molded under the conditions of a mold temperature of 160 ° C., a molding pressure of 3 MPa, and a curing time of 120 seconds, to produce a sealed model for evaluation in which an iron core was inserted. A heat cycle test was performed using the obtained sealing model for evaluation, and the number of cracks generated in 20 evaluation models was examined.

The results are shown in Table 1.

(Example 2, Comparative Examples 1 to 4) Except that the mixing ratio was changed as shown in Table 1, the procedure was the same as in Example 1, and a molding material was prepared. The performance was evaluated. The NBR used in Comparative Example 3 was [HF-01, manufactured by Zeon Corporation].

Table 1 shows the test results.

[0032]

[Table 1]

As can be seen from Table 1, in the heat cycle test, cracks occurred in Comparative Examples 1 to 4, whereas Examples 1 and 2 did not contain any cracks.
It was confirmed that the heat cycle property was excellent. Also,
The molding material of the present invention exhibits excellent low-pressure moldability as can be seen from the results of the spiral flow, and further has a flexural strength,
It was also excellent in mechanical strength such as Charpy impact strength, and it was confirmed that it was well-balanced as a molding material for low pressure sealing.

[0034]

The use of the molding material for low-pressure sealing of the present invention provides a molded article having excellent heat cycle properties and excellent mechanical strength such as fluidity, bending strength, and Charpy impact strength. It is very useful as a molding compound for electric and electronic parts.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 31:08 H01L 23/30 R 83:04) F-term (Reference) 4J002 BF052 CF211 CP033 DL006 FA046 FD016 GQ05 4M109 AA01 CA21 EA11 EB12 EB19 EC03

Claims (3)

[Claims] 1. A silicone rubber containing 5 to 25 parts by weight based on 100 parts by weight of a resin component in which an unsaturated polyester resin and a diallyl phthalate resin are mixed at a weight ratio of 99/1 to 70/30.
A low-pressure sealing molding material, which contains 70 parts by mass and 70 to 180 parts by mass of glass fiber. 2. The mass ratio of the unsaturated polyester resin to the diallyl phthalate resin as the resin component is from 95/5 to 75.
The molding material for low pressure sealing according to claim 1, wherein the ratio is / 25. 3. The silicone rubber having an average particle size of 0.1.
The molding material for low pressure sealing according to claim 1 or 2, wherein the thickness is 1 to 5 µm.