JPH07214739A - Conductive plastic sheet - Google Patents

Abstract

PURPOSE:To obtain a conductive composite plastic sheet excellent in conductivity and dynamic characteristics and having secondary moldability suitable for the packaging of an electronic part by laminating a thermoplastic resin layer containing a conductive filler to the single surface or both surfaces of an aromatic polyester resin layer. CONSTITUTION:A conductive plastic sheet with surface resistivity of 10<10>OMEGA or less is obtained by laminating a conductive layer (B) composed of a thermoplastic resin compsn. containing a thermoplastic resin and a conductive filler to the single surface or both surfaces of a base material layer (A) composed of an aromatic polyester resin. As the conductive filler constituting the conductive layer, various conductive fillers such as a carbon fiber, a metal fiber, a metal powder or carbon black can be used but, in order to obtain dynamic characteristics and secondary moldability, the use of carbon black is especially pref.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC or an electronic device component using an IC, in which a conductive layer made of a thermoplastic resin composition is laminated on one or both sides of a base material layer made of an aromatic polyester resin. The present invention relates to a conductive plastic sheet used for packaging.

[0002]

2. Description of the Related Art Conventionally, vacuum forming trays, embossed carrier tapes, etc. have been known as packaging forms for ICs and electronic equipment parts using the ICs. The plastic sheet, which is the raw material of the vacuum forming tray and the embossed carrier tape, generally has a high surface specific resistance value, so that it is very easy to be charged with an IC.
The possibility of destroying the function of is high. Therefore, as an improvement measure, (1) a method of applying an antistatic agent on the surface of the packaging container,
There have been proposed (2) a method of applying a conductive coating material, (3) a method of kneading and mixing an antistatic agent or a conductive filler such as carbon black into a molding resin.

However, the method (1) has an antistatic effect immediately after coating, but it may flow out due to moisture during long use, the antistatic agent may be removed by friction on the surface, and the surface resistivity may be high. Since it is 10 ¹⁰ Ω or more, it is unsuitable for packaging of IC products such as LSIs which require a strict antistatic effect. In the method (2), the target substrate is limited due to the adhesiveness of the conductive paint, the coating is likely to be non-uniform, the surface is vulnerable to friction, the conductive layer is peeled off, and the antistatic property is lost. It is not desirable because it will destroy it.
In the method (3), in the case of the antistatic agent, if the addition amount is large, the molding process becomes difficult, and if the addition amount is small, the surface resistivity increases. That is, the surface resistivity can actually be reduced only to about 10 ¹¹ Ω, and a sheet having a satisfactory antistatic effect cannot be obtained. Further, in the case of a conductive filler such as carbon black or fine metal powder, it is a very effective method from the viewpoint of the durability of the antistatic effect and the surface resistivity. However,
Since it is necessary to add a large amount of carbon black and metal fine powder, such sheets have a markedly reduced mechanical strength and impact strength, and also have reduced secondary formability such as vacuum forming, pressure forming and hot plate forming. It is not satisfactory as an IC packaging container.

Under such circumstances, a large amount of conductive plastic sheets in which carbon black is kneaded into vinyl chloride resin is currently used. However, vinyl chloride resin produces toxic gas when burned and also has a long life. There is a problem that the plasticizer bleeds due to storage for a certain period of time and contaminates the packaged IC.

As a countermeasure against this, in recent years the calories burned are low,
Plastic sheets that use aromatic polyester resins such as polyethylene terephthalate and polybutylene terephthalate, which do not generate toxic gas during combustion and do not require the addition of plasticizers, are drawing attention, but aromatic polyester resins are hydrolyzed. Easily occurs, and it is difficult to knead carbon black containing a large amount of water.
Further, an aromatic polyester resin generally has a sharp decrease in viscosity when melted, while a thermoplastic resin containing a conductive filler has a high melt viscosity. there were. Therefore, although the above-mentioned problems are not satisfied, the method (2) of applying a conductive coating has been used.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to solve such a drawback, and the inventors of the present invention have made earnest studies on conductive plastic sheets and, as a result, have found that one side of a base material layer made of an aromatic polyester resin or The present invention has been completed by reaching a conductive plastic sheet in which conductive layers made of a thermoplastic resin composition are laminated on both sides.

[0007]

That is, the first aspect of the present invention
The invention of (1) is obtained by laminating a conductive layer made of a thermoplastic resin composition containing (B) a thermoplastic resin and a conductive filler on one surface or both surfaces of a base material layer made of an aromatic polyester resin (A), A second aspect of the present invention is a conductive plastic sheet having a surface resistivity of 10 ¹⁰ Ω or less. The second invention is a conductive plastic obtained by laminating a base material layer and a conductive layer by multi-layer coextrusion molding. Is a sheet,
A third invention is a conductive plastic sheet in which the aromatic polyester-based resin of the base material layer is an aromatic polyester-based resin having no definite melting point, and the fourth invention is that the conductive layer is 100 weight% of the thermoplastic resin. Parts and carbon black 4-5
It is a conductive plastic sheet using a thermoplastic resin composition containing 0 part by weight.

The present invention will be described in more detail below. The aromatic polyester resin used in the substrate layer in the present invention is a polyalkylene terephthalate obtained by polycondensation of terephthalic acid or its dialkyl ester and an aliphatic glycol, or a copolymer mainly composed of such polyalkylene terephthalate. Examples thereof include polyethylene terephthalate and polybutylene terephthalate. Along with the above-mentioned terephthalic acid or its dialkyl ester, other dibasic acid, polybasic acid or its alkyl ester, such as phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, adipic acid, for terephthalic acid or its dialkyl ester. Sebacic acid, trimesic acid, trimellitic acid, their alkyl esters and the like may be mixed and used. Further, examples of the aliphatic glycols include erylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, etc., and other diols or polyhydric alcohols such as aliphatic glycols together with these aliphatic glycols. In contrast, cyclohexanediol, cyclohexanedimethanol, xylylene glycol, 2,2-bis (4-hydroxyphenyl) propane, glycerin,
You may mix and use pentaethritol etc.

The above-mentioned aromatic polyester resin is used as the aromatic polyester resin of the present invention.
Among these, an aromatic polyester resin having no clear melting point is particularly preferable, which comprises terephthalic acid or its dialkyl ester with 20 to 50% of another dibasic acid, polybasic acid or its alkyl ester. It is mixed and / or a mixture of aliphatic glycols with 20 to 50% of other diols or polyhydric alcohols, and has a clear melting point as measured by a differential calorimeter at a heating rate of 20 ° C / min. It is one that does not develop a peak.

The thermoplastic resin for the conductive layer of the present invention includes
The above-mentioned aromatic polyester resin can be used, and further,
Polypropylene resin, polyethylene resin, polystyrene resin, polycarbonate resin, ABS resin,
It is also possible to use an acrylic resin, a polyamide resin, a modified PPE resin and the like, and alloy resins thereof. If the conductive layer has a low compatibility with the aromatic polyester resin and the adhesiveness when forming a multilayer is not sufficient, for example, a group reactive with the aromatic polyester resin such as a glycidyl methacrylate group should be introduced. Alternatively, a copolymer of a monomer compatible with the aromatic polyester resin can be added.

As the conductive filler constituting the conductive layer, various conductive fillers such as carbon fiber, metal fiber, metal powder, and carbon black can be used, but in order to obtain mechanical properties and secondary moldability, The use of carbon black is preferred. Examples of carbon black that can be used in the present invention include furnace black, channel black, and acetylene black. The addition amount of carbon black is 4 to 50 with respect to 100 parts by weight of the above thermoplastic resin.
If it is less than 4 parts by weight, sufficient conductivity cannot be obtained, and if it exceeds 50 parts by weight, the mechanical properties are deteriorated. In addition, various additives such as an antioxidant and a lubricant can be added as a reinforcing material or a processing aid, if necessary.

In the production of the sheet of the present invention, first, a mixture of a conductive filler to be a conductive layer and a thermoplastic resin is kneaded by various kneaders such as a twin-screw extruder and a continuous kneader,
Sheets formed into pellets and then using two or three extruders, to which the resin for the base material layer and the resin for the conductive layer are respectively supplied, and laminated by a multi-layer coextrusion molding method such as a feed block method or a multi-manifold method. To manufacture. When there is a large difference in melt viscosity between the base layer resin and the conductive layer resin in multi-layer coextrusion molding, a bifunctional epoxy compound or a polyacid group compound such as pyromellitic acid is added to the aromatic polyester resin of the base layer for crosslinking. Although it is possible to increase the viscosity, the above-mentioned aromatic polyester-based resin having no clear melting point has a smaller decrease in melt viscosity than general aromatic polyester-based resins, so that multi-layer coextrusion molding can be easily performed.

The total thickness of the sheet obtained by such a coextrusion method is preferably 0.1 to 5.0 m / m, particularly preferably 0.2 to 2.0 m / m. Thickness is 0.1m / m
If less than 5.0 m / m, the strength as a packaging container is insufficient.
If it exceeds, the uneven thickness at the time of secondary molding becomes large and molding becomes difficult. Also, the thickness of the conductive layer is preferably 2 to 70% of the whole,
5 to 50% is particularly preferable. If the wall thickness is less than 2%, it is difficult to process with an extruder, and if it exceeds 70%, mechanical properties,
Secondary formability is reduced. The surface resistivity of the sheet is 10 ¹⁰ Ω
Or less, particularly preferably 10 ⁸ Ω or less.
In addition, the DuPont impact value of the sheet is 0.5 J from the practical point of view.
(Joule) or more is preferable. The sheet of the present invention is excellent in moldability, and it is possible to shape minute ribs by vacuum forming, pressure forming, etc., and a vacuum forming tray for packaging an electronic device component using an IC or an IC as a molded product, Used for embossed carrier tapes, etc.

[0014]

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

Example 1 The raw materials shown in Table 1 were used, and the composition ratios shown in Table 2 were used.
The compound was manufactured. Twin screw extruder PCM-45
(Made by Ikegai Tekko Co., Ltd.), a thermoplastic resin was supplied from a hopper, and carbon black in a molten state of the resin was supplied by a weight feeder from the middle of the extruder to prepare a compound. Further, in forming the sheet, three extruders are used, and the total thickness is 0.3 m / m by the feed block method, and the thickness of the base material layer is 75% of the total. A sheet (consisting of a conductive layer (12.5%) / base material layer (75%) / conductive layer (12.5%)) was prepared. Table 4 shows the evaluation results. The conductive sheet obtained is
It showed good conductivity, mechanical properties and moldability.

Examples 2 to 7 In the same manner as in Example 1, the raw materials shown in Table 1 were used, and the compound was produced and the film was formed at the blending composition ratios shown in Tables 2 and 3. Table 4 shows the evaluation results. The obtained conductive sheet exhibited good conductivity, mechanical properties and moldability.

Comparative Examples 1 to 3 In the same manner as in Example 1, the raw materials shown in Table 1 were used, and the compound was produced and the film was formed at the blending composition ratio shown in Table 3. Table 4 shows the evaluation results. In Comparative Example 1, a three-layer sheet having a total thickness of 0.3 m / m and a substrate layer having a thickness of 75% was formed, but the surface resistivity was insufficient. In Comparative Example 2, film formation was impossible. In Comparative Example 3, the three-layered sheet (conductive layer (3
7.5%) / base material layer (25%) / conductive layer (37.5%)
However, sufficient mechanical properties could not be obtained.

Comparative Example 4 A 0.3 m / m A-PET sheet (Denki Kagaku Kogyo Co., Ltd.) was coated with a conductive paint Exp-5025 (Osaka Printing Ink Mfg. Co., Ltd.), and a clear paint Exp- Fifty
25OP varnish (Osaka Printing Ink Mfg. Co., Ltd.) was applied. The evaluation results are shown in Table 4. Although the electrical conductivity and mechanical properties in the sheet state were good, it was difficult to shape the microribs,
The conductivity of the molded product has also decreased.

The evaluation methods of the sheets of Examples and Comparative Examples are shown below. (1) Thickness of Substrate Layer and Conductive Layer The discharge amount depending on the rotation speed of the substrate layer and conductive layer extruder used for film formation was measured and determined by the discharge amount ratio. (2) Surface resistance Lolester MCP-Tester / Mitsubishi Yuka Co., Ltd., used electrodes with a distance between terminals of 1 cm to make the sheet 10 at equal intervals in the width direction.
The surface resistance was measured at a total of 40 positions on both the front and back sides, and the logarithmic average was taken as the surface resistance. (3) Tensile property According to JIS-K-6732, 1 according to Instron
A tensile test was carried out at a tensile speed of 0 mm / min, and the measured values for elongation at break, strength at break, and tensile elastic modulus in the sheet flow direction and width direction were shown.

(4) DuPont Impact Strength Using a DuPont impact tester / Toyo Seiki Co., Ltd., 300 g,
A weight of 500 g or 1 kg was dropped to obtain a 50% breaking height, and an energy value was calculated from the weight of the weight at that time. The calculation was performed according to JIS-K-7221. (5) Formability and Surface Resistance A tray for IC packaging with minute ribs was formed by a vacuum forming machine manufactured by Kansai Automatic Co., Ltd. Regarding the shapeability, the one in which the minute ribs were formed was marked with ◯, and the one without the shape was marked with x. As for surface resistance, the bottom 10 of the pocket of the molded product is Lorester M
It was measured by CP-Tester / Mitsubishi Petrochemical Co., Ltd., and the fact that it increased by 3 digits or more from the numerical value in the sheet state was x, and the less than 3 digits was o.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

As described above, the thermoplastic resin layer containing the conductive filler is laminated on one or both sides of the aromatic polyester resin layer as the base material by the multi-layer coextrusion molding so that the conductive and mechanical properties can be improved. Thus, it becomes possible to obtain a composite plastic sheet having excellent secondary moldability for use in packaging ICs and electronic parts.

Claims (4)

[Claims] 1. A conductive layer made of a thermoplastic resin composition containing (B) a thermoplastic resin and a conductive filler is laminated on one or both sides of a base material layer made of (A) an aromatic polyester resin. A conductive plastic sheet having a surface resistivity of 10 ¹⁰ Ω or less. 2. The conductive plastic sheet according to claim 1, wherein the base material layer and the conductive layer are laminated by multi-layer coextrusion molding. 3. The conductive plastic sheet according to claim 1, wherein the aromatic polyester resin of the base material layer is an aromatic polyester resin having no definite melting point. 4. The conductive plastic sheet according to claim 1, wherein the conductive layer is a thermoplastic resin composition containing 100 parts by weight of a thermoplastic resin and 4 to 50 parts by weight of carbon black. .