JP2002264272A - Conductive composite plastic sheet and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a conductive composite plastic sheet which has conductivity and is excellent in mechanical strength, rigidity, and impact resistance and suitable for packaging IC products, and a molding obtained by thermoforming the sheet. SOLUTION: In the conductive composite plastic sheet and the molding obtained from the sheet, (A) on one side or both sides of a base material layer comprising 100 pts.wt. of a polyphenylene ether resin composition containing 20-96 pts.wt. of a polyphenylene ether resin and 80-4 pts.wt. of a polystyrene resin, (B) a conductive layer of a conductive resin composition which contains 5-50 pts.wt. of a conductive material per 100 pts.wt. of a polystyrene resin or an ABS resin and the surface resistivity of which is 10<10> Ω or below is laminated integrally by a coextrusion method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive composite plastic sheet which has conductivity and is excellent in mechanical strength, rigidity and impact resistance, and is suitable for packaging IC products. Related to molded articles.

[0002]

2. Description of the Related Art Conventionally, vacuum forming trays, embossed carrier tapes, and the like have been known as packaging forms of ICs and electronic device parts using ICs. The plastic sheet, which is the raw material of the vacuum forming tray or the embossed carrier tape, is generally very easily charged because of its high surface resistivity.
C function is likely to be destroyed. Therefore, (1) a method of applying an antistatic agent to the surface of the packaging container as an improvement measure,
There have been proposed (2) a method of applying a conductive paint, and (3) a method of kneading a conductive resin such as an antistatic agent or carbon black into a molding resin.

[0003] However, the method (1) exhibits an antistatic effect immediately after coating, but the antistatic agent flows out with moisture during use for a long time, or the antistatic agent is separated due to surface friction. And the surface resistivity is 10 ⁹ to 10 ¹² Ω
Therefore, it is unsuitable for packaging products such as LSIs that require a strict antistatic effect. In the method (2), the target base material is limited from the viewpoint of the adhesion of the conductive paint, and
The coating is likely to be non-uniform, and is weak against surface friction, so that the conductive layer is peeled off, losing antistatic properties and destroying IC products, which is not preferable. In the method (3), in which the antistatic agent is kneaded, molding is difficult if the amount is large, and the surface resistivity increases if the amount is small. That is, actually, the surface specific resistance value can be reduced only to about 10 ¹¹ Ω, and a sheet having a sufficient antistatic effect cannot be obtained. Also, in the case of a conductivity-imparting material such as carbon black or metal fine powder, it is a very effective method from the viewpoint of the durability of the antistatic effect and the surface resistivity, but a large amount of carbon black or metal fine powder is used. Powder addition is required. Such a sheet has a remarkable reduction in mechanical strength and impact strength, and further has a low secondary formability such as vacuum forming, pressure forming and hot plate forming, and is not satisfactory as an IC packaging container.

[0004] As a measure for improvement, Japanese Patent Publication No.
In JP-A No. 2, a conductive composite plastic container is proposed in which a conductive resin is laminated on both surfaces of a polystyrene or ABS resin sheet base material. However, in recent years, the speed of the semiconductor mounting process has been increased, the mechanical strength of the packaging container has been increased, and the diameter of the IC lead has been reduced and the bending is likely to occur. There is a strong demand for improved mechanical strength, but none of them satisfy this demand.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks. (A) A polyphenylene ether-based resin composition containing 20 to 96 parts by weight of a polyphenylene ether resin and 80 to 4 parts by weight of a polystyrene-based resin. Thing 1
On one side or both sides of the substrate layer consisting of 00 parts by weight,
(B) A conductive layer made of a conductive resin composition containing 5 to 50 parts by weight of a conductivity-imparting material with respect to 100 parts by weight of a polystyrene-based or ABS-based resin and having a surface resistivity of 10 ¹⁰ Ω or less, It is an object of the present invention to provide a conductive composite plastic sheet characterized by being integrally laminated by an extrusion method and a molded product obtained by thermoforming the sheet.

[0006]

That is, the present invention provides (A) a base material layer comprising 100 to 100 parts by weight of a polyphenylene ether resin composition comprising 20 to 96 parts by weight of a polyphenylene ether resin and 80 to 4 parts by weight of a polystyrene resin. (B) polystyrene or A on one or both sides of
A conductive layer made of a conductive resin composition containing 5 to 50 parts by weight of a conductivity-imparting material with respect to 100 parts by weight of a BS resin and having a surface specific resistance of 10 ¹⁰ Ω or less is integrally laminated by a co-extrusion method. A conductive composite plastic sheet and a molded article obtained by thermoforming the sheet.

Hereinafter, the present invention will be described in more detail. First, the base material layer will be described. The polyphenylene ether resin used in the present invention is a homopolymer or a copolymer described in US Pat. No. 3,383,435. The polyphenylene ether resin used for the base material layer is composed of a polyphenylene ether resin and a polystyrene resin, and the content of the polyphenylene ether resin in 100 parts by weight of the resin composition is preferably 20 to 96 parts by weight, and less than 20 parts by weight is sufficient. 96
Exceeding parts by weight makes processing with an extruder difficult. Further, within this range, 20 to 88 parts by weight is particularly preferred. As the polystyrene resin, an impact-resistant polystyrene resin containing 2 to 10% by weight of a rubber component or a mixture of an impact-resistant polystyrene resin containing the same amount of a rubber component and a transparent polystyrene resin for the effect of reinforcing impact resistance is used. Is preferred.

Further, it is possible to add a modifier to improve mechanical properties such as impact resistance and secondary formability. As a modifier of the polyphenylene ether-based resin, ethylene-vinyl acetate copolymer resin and ethylene-ethyl acrylate copolymer resin are known, and in the present invention, ethylene-ethyl acrylate copolymer resin is used. Among these, an ethylene-ethyl acrylate copolymer resin having a content of ethyl acrylate of 5 to 20% by weight is most preferable. The amount of the ethylene-ethyl acrylate copolymer resin to be added is preferably 2 to 20 parts by weight, particularly preferably 2 to 10 parts by weight, per 100 parts by weight of the polyphenylene ether resin. If the amount is less than 2 parts by weight, the effect as a modifier cannot be sufficiently obtained. If the amount is more than 20 parts by weight, the compatibility may be lowered to cause peeling.

In the case where peeling occurs due to the addition of the modifier, the peeling can be prevented by adding 0.3 to 10 parts by weight of a filler to 100 parts by weight of the polyphenylene ether-based resin. . The amount of filler added is 0.
If the amount is less than 3 parts by weight, a sufficient effect cannot be obtained. Inorganic fillers such as calcium carbonate, talc, and mica can be used as the filler, but carbon black is optimal.
Further, various additives such as an antioxidant and a lubricant can be added as necessary as processing aids, and the scrap of the conductive composite plastic sheet of the present invention can be further added to such an extent that the mechanical properties are not significantly reduced. .

Next, the conductive layer will be described. The resins used in the present invention are polystyrene resins and ABS resins. As the polystyrene-based resin, an impact-resistant polystyrene resin containing 2 to 10% by weight of a rubber component or a mixture of the impact-resistant polystyrene resin and a general-purpose transparent polystyrene resin can be used for the effect of reinforcing the impact resistance. Also,
The ABS resin is composed of a mixture of an acrylonitrile-styrene copolymer and an acrylonitrile-butadiene-styrene copolymer, and the content of the acrylonitrile-butadiene-styrene copolymer with respect to 100 parts by weight of the resin is 10 to 80. The weight part is preferable, and the ratio of the resin component and the rubber component (butadiene component) in the acrylonitrile-butadiene-styrene copolymer is preferably in the range of 1: 5 to 2: 1.

Various conductive fillers such as carbon black, carbon fiber, metal fiber and metal powder can be used as the material for imparting conductivity to the conductive layer. The use of black is preferred. The carbon black used in the present invention includes furnace black, channel black, acetylene black and the like, and preferably has a carbon purity of 98% or more and a volatile content of 1.5% or less. Volatile content is 1.
If it exceeds 5%, foaming may occur on the sheet surface during extrusion. Carbon black is added in an amount of 5 to 50 parts by weight based on 100 parts by weight of the resin. If the amount is less than 5 parts by weight, the surface resistivity does not become 10 ¹⁰ Ω or less. Would. In addition, various additives such as an antioxidant and a lubricant can be added as a processing aid, if necessary.

In order to produce the sheet and the molded product of the present invention, first, pellets for the base material layer and the conductive layer are obtained by a kneader such as a twin screw extruder or a continuous kneader. A method is used in which each of the above-mentioned raw materials is supplied by a single extruder, and is co-extruded and laminated by a known method such as a feed block method or a multi-manifold method. An appropriate range of these processing temperatures is in the range of 220 to 300 ° C. If the temperature is lower than this temperature range, sufficient molding cannot be performed, and if the temperature is high, the resin may be deteriorated.

The total thickness of the sheet obtained by such a co-extrusion method is preferably 0.1 to 5.0 mm, particularly preferably 0.2 to 2.0 mm. 0.1mm thickness
If it is less than 5, the strength as a packaging container is insufficient, and if it exceeds 5.0 mm, secondary molding becomes difficult. Further, the thickness of the conductive layer is preferably 2 to 70% of the whole, and particularly preferably 5 to 50%. If the wall thickness is less than 2%, the surface conductivity of the secondary molded product may be lost, and if it exceeds 70%, the mechanical properties and the secondary moldability deteriorate. The molded article obtained by thermoforming the conductive composite plastic sheet of the present invention can be used for a carrier tape for packaging IC products, a soft tray, and the like. In order to obtain the molded product, thermal processing may be performed by a known method such as vacuum forming, pressure forming, hot plate forming and the like. The shape of a molded product is determined by the shape of an IC product or the like to be packaged, but generally has an embossed shape. When the molded product of the sheet of the present invention is used as a carrier tape, the mechanical strength of the product is increased as compared with the conventional product, so that high-speed mounting of semiconductors is possible and the protection performance of IC is also improved. .

[0014]

The present invention will be described below with reference to examples. Example 1 A polyphenylene ether resin, an impact-resistant polystyrene resin, and an ethylene-ethyl acrylate copolymer resin were blended and kneaded for a base material layer to obtain pellets. Further, an impact-resistant polystyrene resin and carbon black were blended and kneaded for a conductive layer to obtain a pellet. Using these pellets, using three extruders, a conductive layer / substrate layer / sheet having a thickness of the entire sheet of 0.3 mm and a thickness of the substrate layer of 75% of the whole by a feed block method. A three-layer sheet composed of a conductive layer (thickness ratio: 1/6/1) was prepared.
Table 1 shows the trade names of the raw material resins, and Table 2 shows the composition of the base material layer and the conductive layer. Furthermore, these sheets are 24 mm wide.
13mm, 13mm long, 19m wide by vacuum forming
m and a depth of 3 mm were embossed to obtain a carrier tape. Table 4 shows the evaluation results.

Examples 2 to 4 In the same manner as in Example 1, the pellets were blended and kneaded with the blending compositions of the base material layer and the conductive layer shown in Table 2 to prepare pellets. Using an extruder, a conductive layer / substrate layer / conductive layer (thickness ratio: 1 /
6/1) was prepared. Table 4 shows the evaluation results. Comparative Examples 1 to 4 In the same manner as in Example 1, with the compounding composition of the base material layer and the conductive layer shown in Table 3, kneading and kneading were performed to produce pellets, and using these pellets, three extruders were used. A sheet was prepared using the feed block method. Table 5 shows the evaluation results. Comparative Example 5 A conductive resin composition was prepared according to the composition shown in Table 3, and a single extruder was used to obtain a 0.3 mm single layer sheet. Table 5 shows the evaluation results.

Various evaluation methods are described below. (1) Thickness of base material layer At the time of film formation, the discharge amount based on the rotation speed of the extruder for the base layer and the conductive layer was measured and determined by the discharge amount ratio. (2) Surface resistance By using Lorester MCP-Tester / Mitsubishi Yuka Co., Ltd., measure the surface resistance of 10 places at equal intervals in the width direction of the sheet and a total of 40 places on the front and back sides of the sheet at a distance of 10 mm. The surface resistance was determined.

(3) Tensile properties In accordance with JIS-K-6732, a tensile test was performed by an Instron at a tensile speed of 10 mm / min, and measured values for the sheet flow direction on the left and the width direction on the right. . (4) Impact strength 300 g using a DuPont impact tester / Toyo Seiki Co., Ltd.
A 500 g or 1 kg weight was dropped, a 50% breaking height was determined, and an energy value was calculated from the weight of the weight at that time. The calculation was performed according to JIS-K-7211.

(5) Surface Resistance of Molded Product In the molded product, four points of surface resistance between the bottoms of adjacent pockets were measured by Loresta MCP-Tester / Mitsubishi Yuka Co., Ltd., and the logarithmic average was taken as the surface resistance. (6) Tensile strength of molded product A molded product of 24 mm width and 100 mm length is
A sample that did not break when pulled by a load of 0 kgf was rated as “O”, and a sample that broke when rated was “X”.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

As described above, a polyphenylene ether-based resin composition comprising a polyphenylene ether resin and a polystyrene-based resin is provided on one or both sides of a sheet substrate.
Semiconductor packaging suitable for packaging IC products, having conductivity and excellent mechanical strength, rigidity, impact resistance, etc. by laminating a polystyrene or ABS resin containing a conductivity imparting material. It is possible to obtain a conductive composite plastic sheet for use and a molded product obtained by thermoforming the sheet.

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Claims (2)

[Claims] 1. A polyphenylene ether resin (A)
96 parts by weight, 100 parts by weight of a polyphenylene ether-based resin composition containing 80 to 4 parts by weight of an impact-resistant polystyrene resin or a mixture of an impact-resistant polystyrene resin and a transparent polystyrene resin, and an ethylene-ethyl acrylate copolymer resin 2 One or both sides of the base material layer having a surface specific resistance of 10 to ¹⁰ parts by weight with respect to 100 parts by weight of the polystyrene or ABS resin (B). A conductive composite plastic sheet other than for a carrier tape , wherein a conductive layer made of a conductive resin composition having a resistance of Ω or less is integrally laminated by a co-extrusion method. 2. A molded article excluding a carrier tape obtained by thermoforming the conductive composite plastic sheet according to claim 1.