JP3324683B2 - Conductive composite plastic sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a conductive resin sheet used for packaging electronic parts and the like, which has excellent mechanical strength by using a copolymer resin of styrene and maleic anhydride for a base layer in an IC. This makes it possible to provide a low-cost packaging container with high protection for contents such as.

[0002]

2. Description of the Related Art Injection trays, vacuum forming trays, magazines, embossed carrier tapes, and the like have conventionally been used as packaging forms for ICs and electronic components using ICs. In order to prevent the occurrence of static electricity, a method of removing static electricity using an antistatic agent, a conductive paint, a conductive filler, or the like has been proposed. Among them, a method of kneading carbon black is widely and generally used to obtain particularly stable static electricity removing performance.

Conventionally, resins for dispersing carbon black include polyvinyl chloride resin, polypropylene resin, polyethylene terephthalate resin and polystyrene resin for general use, and modified polyphenylene ether resin and polycarbonate resin for heat resistance at 100 ° C. or higher. Is used. Among these resins, polystyrene resin is used for general use, and modified polyphenylene ether resin is used for heat resistance. (1) Fluidity and moldability are remarkably reduced even when a large amount of carbon black is added as compared with other resins. And (2) excellent dimensional stability when used as a packaging material due to lack of crystallinity, and polystyrene resin is also excellent in cost. However, polystyrene resin has a drawback that its rigidity is lower than other resins, and the protective property of the contents is low when used as a packaging container.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks and is intended to solve the problem of a conductive composite plastic sheet in which a conductive resin composition is laminated on one or both sides of a sheet substrate made of a polystyrene resin. By using a copolymer resin of styrene and maleic anhydride for the layer, it is an object of the present invention to provide a conductive composite plastic sheet having excellent protection of contents when used as a packaging container.

[0005]

That is, the first aspect of the present invention is as follows.
Of the present invention relates to (A) one side of a polystyrene resin sheet substrate
Or both sides, (B1) 100 weight of polystyrene resin
Parts (B2) 5 to 50 parts by weight of carbon black
(B) Composite plastic laminated with conductive resin composition
Backing sheet, the surface hardness of the conductive resin composition layer
Resistance value is 10 ^Two-10^TenΩ and (A)
Polystyrene resin is a copolymer of styrene and maleic anhydride
Conductive composite plastic characterized by being a united resin
It is a worksheet.

A second invention of the present invention is that (A) one or both sides of a polystyrene resin sheet base material contains (B2) 5 to 50 parts by weight of carbon black (B2) based on 100 parts by weight of a polystyrene resin. (B) In a composite plastic sheet laminated with a conductive resin composition, the composite plastic sheet has a surface specific resistance of 10 ² to 10 ^10.
And (A) a block copolymer made of an impact-resistant polystyrene resin, an olefin resin, styrene and a conjugated diene, a styrene and a conjugated diene, At least one resin selected from a resin obtained by hydrogenating a block copolymer produced by the method described above with a copolymer resin of styrene and maleic anhydride;
Is a conductive composite plastic sheet characterized by containing 4 to 20% by weight based on the total weight of the conductive composite plastic sheet.

Hereinafter, the present invention will be described in more detail. A copolymer resin of styrene and maleic anhydride is used for the sheet substrate of the present invention. The content of maleic anhydride in the copolymer resin of styrene and maleic anhydride is 1 to 30% by weight.
Is preferred. If the amount is less than 1% by weight, sufficient rigidity as a packaging container cannot be obtained. If the amount exceeds 30% by weight, thermal decomposition tends to occur when the sheet is heated and formed into a packaging container.

The sheet base material of the present invention may contain various additives such as a lubricant, a plasticizer, a processing aid and a reinforcing agent in order to improve the flow properties of the composition and the mechanical properties of the molded article, if necessary. It is possible to add a resin component such as an impact-resistant polystyrene resin, an olefin resin, a block copolymer made of styrene and a conjugated diene, and a block copolymer made of styrene and a conjugated diene. It is preferable to add at least one or more of the resins obtained by the addition.

Examples of the olefin resin include a homopolymer of ethylene or propylene, a copolymer containing ethylene or propylene as a main component, and a blend thereof. In the present invention, among these, a copolymer of ethylene and ethyl acrylate is particularly preferably used.

The conjugated diene of the block copolymer produced from styrene and a conjugated diene includes butadiene and isoprene. Specific examples of the block copolymer include a block copolymer of styrene and butadiene and a block copolymer of styrene and isoprene. This block copolymer is specifically a branched star-shaped block copolymer described in U.S. Pat. No. 3,281,383, or, for example, (S1)-(B
There is a linear block copolymer having at least three blocks such as u)-(S2) (S1 and S2 indicate blocks formed from styrene, and Bu indicates blocks formed from butadiene or isoprene). The block copolymers made from styrene and conjugated dienes used in the present invention may each be selectively or partially hydrogenated.

In the present invention, at least one of a resin obtained by hydrogenating an impact-resistant polystyrene resin, an olefin resin, a block copolymer produced from styrene and a conjugated diene, and a block copolymer produced from styrene and a conjugated diene is used. It is preferable to add one or more types, and the total amount thereof is 4 to 2 in the copolymer resin composition of styrene and maleic anhydride of the sheet substrate.
0 % by weight is preferred. If it is less than 4% by weight, the effect of improving the mechanical strength and fluidity cannot be obtained, and if it exceeds 20 % by weight, the rigidity of the obtained sheet decreases, and the protection of the contents when used as a packaging container decreases. Would.

In the present invention, the polystyrene resin used in the conductive resin composition means a general polystyrene resin, an impact-resistant polystyrene resin, or a mixture containing these as a main component.

According to the present invention, the resin contained in the conductive resin composition
Furnace Black, Chan Black
Flannel black and acetylene black. Preferably
Has a large specific surface area and a small
It provides electrical conductivity. For example, C. F. (Su
per Conductive Furnace),
E. FIG. C. F. (Electric Conductiv
e Furnace), Ketchen Black (Lion
-AKZO brand name) and acetylene black
You. The amount of carbon black added depends on the
Surface resistivity value of 10^Two-10^TenΩ
The amount can be adjusted depending on the resin composition.
Polystyrene resin in the conductive resin composition 1
Carbon black in an amount of 5 to 50 parts by weight.
It is an enclosure. If the added amount is small, sufficient conductivity cannot be obtained and
The surface specific resistance value rises, and if it is too large,
Deterioration of uniform dispersibility, remarkable decrease in molding processability, mechanical
Characteristic values such as strength are reduced. Surface resistivity is 1
0^TenIf it exceeds Ω, a sufficient antistatic effect cannot be obtained and 10
^TwoIf it is less than Ω, the conductivity is too good and IC may be broken.
is there.

The conductive resin composition of the present invention may contain various additives such as a lubricant, a plasticizer, a processing aid and a reinforcing agent in order to improve the flow properties of the composition and the mechanical properties of the molded article, if necessary. And other resin components can be added.

In order to produce the composite plastic sheet of the present invention, first, raw materials to be used as a base material layer and a conductive layer are kneaded by known methods such as a Banbury mixer and a twin-screw extruder to form pellets. The obtained base layer resin composition and conductive resin composition can be used alone in a sheet or film form by an extruder or the like, and can be laminated by a heat lamination method, a dry lamination method, an extrusion lamination method, or the like,
It is also possible to integrally mold by a known co-extrusion method such as a feed block method or a multi-manifold method.

The total thickness of the sheet of the present invention is 0.1 to
It is 3.0 mm, and the conductive resin composition layer needs to be laminated on one side or both sides of the sheet substrate. The ratio of the thickness of the conductive resin composition to the total thickness is preferably 2% or more on each side and 80% or less on both sides. If the total thickness is less than 0.1 mm, the strength as a packaging container obtained by molding the sheet is insufficient, and if it exceeds 3.0 mm, molding such as air pressure molding, vacuum molding, and hot plate molding becomes difficult. When the ratio of the thickness of the conductive resin composition layer to the entire thickness is less than 2% on one side, the surface resistivity of the packaging container obtained by molding the sheet becomes extremely high, and a sufficient antistatic effect is obtained. If the combined plastic sheet exceeds 80%, the properties such as mechanical strength of the composite plastic sheet deteriorate.

[0017]

As described above, in a conductive composite plastic sheet in which a conductive resin composition is laminated on one or both sides of a sheet substrate made of a polystyrene resin, a copolymer of styrene and maleic anhydride is formed on the substrate layer. By using a resin, it is possible to provide a conductive composite plastic sheet that is excellent in protecting the contents when used as a packaging container.

[0018]

The present invention will be described in more detail with reference to the following examples. Example 1 Impact-resistant polystyrene resin HI as a conductive layer resin composition
-E4 (Denki Kagaku Kogyo Co., Ltd.) 100 parts by weight, DENKA black granules (Denki Kagaku Kogyo Co., Ltd.) 24 parts by weight were uniformly mixed by a tumbler, and then kneaded using a φ45 mm vent-type twin-screw extruder, followed by strand cutting. The pellet obtained by the method was used. Styrene-maleic anhydride copolymer resin Dylark23 as base layer resin composition
2 (Sekisui Plastics Co., Ltd.) with φ65mm extruder (L
/ D = 28), the conductive resin composition is extruded from a φ40 mm extruder (L / D = 26) and molded by a feed block method using a 500 mm width T die to form a laminated sheet having a total thickness of 300 μm. Obtained.

Example 2 Impact-resistant polystyrene resin HI as a conductive layer resin composition
-E4 (Denki Kagaku Kogyo Co., Ltd.) 100 parts by weight, DENKA black granules (Denki Kagaku Kogyo Co., Ltd.) 24 parts by weight were uniformly mixed by a tumbler, and then kneaded using a φ45 mm vent-type twin-screw extruder, followed by strand cutting. The pellet obtained by the method was used. Further, a styrene-maleic anhydride copolymer resin Dylark is used as the base layer resin composition.
A mixture of 232 (Sekisui Chemical Co., Ltd.) 90% by weight and an impact-resistant polystyrene resin HI-E4 (Denki Kagaku Kogyo Co., Ltd.) 10% by weight was uniformly mixed by a tumbler, and then a φ45 mm vented twin-screw extruder was used. Kneading using
Pellets obtained by the strand cutting method were used. The obtained base layer resin composition was extruded with a φ65 mm extruder (L / D =
28), the conductive resin composition was extruded with a φ40 mm extruder (L
/ D = 26), and molded by a feed block method using a 500 mm wide T-die to obtain an overall thickness of 300 mm.
A μm laminated sheet was obtained.

Example 3 Impact Resistant Polystyrene Resin HI as Resin Composition for Conductive Layer
-E4 (Denki Kagaku Kogyo Co., Ltd.) 100 parts by weight, DENKA black granules (Denki Kagaku Kogyo Co., Ltd.) 24 parts by weight were uniformly mixed by a tumbler, and then kneaded using a φ45 mm vent-type twin-screw extruder, followed by strand cutting. The pellet obtained by the method was used. Further, a styrene-maleic anhydride copolymer resin Dylark is used as the base layer resin composition.
250 (Sekisui Chemical Co., Ltd.) and 20 % by weight of a resin tuftec H-1041 (Asahi Kasei Chemical Co., Ltd.) obtained by hydrogenating a block copolymer produced from styrene and a conjugated diene are uniformly mixed by a tumbler. After that, the mixture was kneaded using a φ45 mm vent type twin screw extruder, and pellets obtained by a strand cut method were used. The obtained base material layer resin composition was φ65 mm extruder (L / D = 28), and the conductive resin composition was φ40 mm
Extruded from an extruder (L / D = 26), 500 mm width T
It was molded by a feed block method using a die to obtain a laminated sheet having a total thickness of 300 μm.

Comparative Example 1 Impact-resistant polystyrene resin HI was used as the resin composition for the substrate layer.
The same procedures were performed as in Example 1 except that -E4 (Electrical Chemical Industry Co., Ltd.) was used. Table 1 shows the evaluation results.

[0022]

[Table 1]

Each evaluation was performed by the following methods. (1) Surface resistance value An arbitrary 10 points on the surface of the obtained sheet were measured with a Lorester surface resistance meter (manufactured by Mitsubishi Yuka) with the distance between the electrodes being 10 mm, and the logarithmic average value was defined as the surface resistance value. (2) Strength at Break, Tensile Modulus The obtained sheet was measured for a No. 2 type test piece at a tensile speed of 10 mm / min in accordance with JIS-K-7113.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 25/08 C08L 25/08 (56) References JP-A-9-76422 (JP, A) JP-A-9-76425 (JP) , A) JP-A-3-87097 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (2)

(57) [Claims] 1. A polystyrene resin sheet (B1) is coated on one or both sides of a polystyrene resin sheet base material (A1).
In a composite plastic sheet obtained by laminating a conductive resin composition (B2) containing 5 to 50 parts by weight of carbon black with respect to parts by weight, the surface specific resistance of the conductive resin composition layer is 10 ² to 10. A conductive composite plastic sheet having a resistivity of ¹⁰ Ω and wherein (A) the polystyrene resin is a copolymer resin of styrene and maleic anhydride. 2. A method according to claim 1, wherein (A) the polystyrene resin is a copolymer resin of styrene and maleic anhydride, a block copolymer produced from an impact-resistant polystyrene resin, an olefin resin, styrene and a conjugated diene, styrene and Copolymerization of styrene and maleic anhydride with at least one resin selected from resins obtained by hydrogenating a block copolymer produced from a conjugated diene
2. The conductive composite plastic sheet according to claim 1, wherein the content is 4 to 20% by weight based on the total weight of the composite resin. 3.