JPS6335967Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a packaging bag made of plastic film that has high conductivity and does not generate static electricity.

Conductive packaging is required for packaging electronic components and products such as ICs and printed wiring boards incorporating ICs. This is because if the packaging material is non-conductive and is charged with static electricity, friction between the packaged item and the packaging material and each other will generate high-voltage electrostatic charging, which often causes dielectric breakdown of the packaged item. This is because there is a risk of impairing its quality, and for this reason various conductive packaging materials are used.

Generally, plastic films kneaded with carbon black, metal or metal oxide powder are often used as conductive packaging materials. On the other hand, it is also known to make a transparent conductive film by kneading a surfactant into plastic, but the volume resistivity value (hereinafter abbreviated as ρv) obtained by this method has the disadvantage that objects cannot be observed. ) was insufficiently reduced, making it unsuitable for the above-mentioned packaging materials.

Recently, tin oxide-based ultrafine powders have been provided on the market as metal oxide powders, which have an average particle size in the range of 10 to 100 nm, which is smaller than the wavelength of visible light, and therefore are suitable for transparent plastics. Even when mixed in a considerable amount in a material, its transparency hardly decreases, and its ρv is 0.1 to 10Ω・cm.
It has relatively good conductivity.

However, this ultrafine powdered tin oxide material is difficult to manufacture and expensive, and it is desirable to reduce its usage as much as possible as a material for packaging materials.

In view of the above conditions, the present invention combines a highly conductive opaque plastic film containing carbon black and a semiconductive transparent plastic film containing tin oxide ultrafine powder to make the inner packaging material transparent at least in part. It is possible to observe
The conventional problems are solved by providing a conductive packaging bag that exhibits good antistatic properties as a whole.

In other words, the antistatic packaging bag of the present invention includes a part of the bag containing carbon black and an opaque, highly conductive plastic film having a ρv of 10 ³ Ω·cm or less, and the remainder containing tin oxide ultrafine powder. do
A plastic film bag made of transparent semiconductive plastic film having a ρv of 10 ⁵ to ¹⁰ Ω·cm.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an opaque highly conductive film 2 containing carbon black and a transparent semiconductive film 3 containing ultrafine tin oxide powder, connected to form opposing bag walls to form a cylindrical shape. A flat bag 1 made of plastic film is shown in which a bottom portion 4 is formed by adhesively sealing one opening edge.

This bag 1 uses, for example, two extruders to supply a highly conductive plastic kneaded with carbon black from one side and a semiconductive plastic kneaded with ultrafine tin oxide powder from the other to one annular die. The film can be easily produced by extruding the film into a tubular shape, using an inflation operation to form a tubular film of a desired thickness, and then cutting the film into a predetermined length and welding it.

The ratio of the areas occupied by the highly conductive film 2 and the semiconductive film 3 must be adjusted and changed as appropriate depending on the antistatic conditions required for packaging.
Therefore, if antistatic properties are extremely required, the area of the transparent semiconductive film must be reduced, but in such a case, the transparent semiconductive film portion is The bag should be designed to be placed in a convenient position for viewing the object.

Figure 2 shows a case where the transparent semiconductive film 3 has a narrow width and is placed at a position that divides the circumference of the bag material tube into thirds, and the wide opaque conductive film 2 occupies a large area. In this example, according to the extrusion inflation method described above, both parts are arranged vertically in parallel as shown in the figure, but by using a film adhesion method, etc., the arrangement direction of both parts is changed horizontally or diagonally,
Of course, it can be adapted to suit the conditions of the packaged product.

In order to improve the strength of the bag 1, a transparent semiconductive film 3 containing tin oxide ultrafine powder may be used.
It is preferable to reinforce the material by laminating it on the entire inner surface of the bag 1 as shown in FIG. 3, or on the entire outer surface of the bag 1 as shown in FIG. Static electricity generated due to friction with the bag is extremely easily discharged to the outside by the highly conductive film, preventing high-voltage static electricity from being charged, preventing electrical damage to the packaged items, and making it possible to observe the inside of the packaging bag. It is possible.

Although the carbon black which is a highly conductive material in the present invention may be any ordinary carbon black, it is preferable to use highly conductive carbon black to further increase the effects of the present invention. In addition, the tin oxide ultrafine powder has an average particle size of 10 to 100 nm and a ρv of 0.1 to 100 nm.
A material with a conductivity of 10 Ω cm can impart conductivity without impairing the transparency of plastics, and a suitable example of this type of product is "Conductive Powder T-1" manufactured by Mitsubishi Metals Co., Ltd. It is.

Although general-purpose thermoplastic synthetic resins can be used as the film material plastic, polyolefins such as polyethylene and polypropylene are suitable from the viewpoint of film formability and cost.

The plastics used for conductive films and semi-conductive films should be of the same type when manufactured by the extrusion inflation method described above; They may be of different types as long as they exhibit sealing properties.

The amount of carbon black and tin oxide ultrafine powder added to plastics varies slightly depending on the type of plastic, but both are suitable for plastics.
The amount is selected in a range of 10 to 50 parts by weight based on 100 parts by weight, and is kneaded and formed into a film by a conventional method.

The thickness of the film is usually 30~ for single layer.
The appropriate thickness is 200μ, and in the case of a multilayer structure, the semiconductive film located on the inside or outside has a thickness in the range of 10 to 50μ.

As explained above, the antistatic packaging bag of the present invention is a packaging bag that has good conductivity and partial transparency, and is particularly suitable for the protective sealing of packaged items that are susceptible to electrostatic damage. It is.

[Brief explanation of the drawing]

The drawing is a perspective view showing an embodiment of the present invention. Figure 1 shows a flat bag, Figure 2 shows a cylindrical bag material,
Figure 3 shows a case where a part of a multi-layer flat bag with a semi-conductive layer on the inner layer is cut away, and Figure 4 shows a case where a part of a multi-layer flat bag with a semi-conductive layer on the outer layer is cut out. Indicate the case. 1... Bag, 2... Good conductive film, 3... Semi-conductive film, 4... Bottom.

Claims (1)

[Scope of utility model registration request] An opaque, highly conductive film portion containing carbon black and having a volume resistivity of 10 ³ Ω・cm or less, and a 10 ⁵ to ¹⁰ Ω・cm containing ultrafine tin oxide powder.
An antistatic packaging bag made of plastic film and comprising a transparent semiconductive film portion having a volume resistivity of cm.