JPH01103439A - Tear sheet possessing permanent antistatic property - Google Patents

Abstract

PURPOSE:To obtain a sheet which is rich in water resistance, provided with permanent antistatic properties and superior in dustproof effect and can endure repeated use, by a method wherein a thermoplastic resin film containing a conductive fiber is laminated on one side or both sides of the thermoplastic resin sheet of a predetermined thickness for molding and surface resistivity is made a predetermined value. CONSTITUTION:A tear sheet can be molded integrally by laminating a thermoplastic resin film, which has been obtained by containing a conductive fiber, on one side or both sides of the thermoplastic resin film through coextrusion molding. The thermoplastic resin film containing a conductive fiber is of the film comprised of by compounding thermoplastic resin with the conductive fiber and a thickness range of 50-20mum is preferable. A carbon fiber, a metallic fiber comprised of aluminum, brass and stainless steel, a metallized glass fiber obtained by coating a glass fiber with silver or copper and synthetic fiber into which metallic fine powder of the silver or the copper or the brass or tin has been mixed up can be mentioned as the conductive fiber. A range of 0.3-15mm is appropriate for thickness of the tear sheet. Then it is necessary that surface resistivity of antistatic properties of the tear sheet is 10<10>OMEGA or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tear sheet (hereinafter simply referred to as a sheet) for conveying containers.

More specifically, IQIO is a surface-resistant wood made by laminating a thermoplastic resin film containing conductive fibers on one or both sides of a thermoplastic resin sheet with a thickness of 0.3 to 15 mm.
Ω or less, and preferably has a coefficient of friction on one side larger than the coefficient of friction on the other side, and has permanent antistatic performance, and is highly water resistant and can be washed. The sheet does not turn black because it has permanent antistatic properties without using carbon black, making it suitable for use in the pharmaceutical and food fields, which have high hygiene requirements, as well as for use in unfilled containers. This tear sheet is highly dustproof and can withstand repeated use. The present invention also relates to a tear sheet that has heat resistance and rigidity, can withstand high-temperature sterilization, and is less prone to bending, making it easier to stack containers in multiple stages and improving work efficiency.

[Conventional technology]

In recent years, metal containers used for soft drinks, beer, cooking oil, canned goods, etc., glass containers used for pharmaceuticals, industrial chemicals, liquid seasonings, etc., and plastic containers used for liquid detergents, seasonings, ice cream, etc. A wide variety of containers are used in large quantities in many fields, and most of the cargo handling operations such as packaging and transporting these containers are automated.

One of the above-mentioned packaging and transportation methods is uniy) loading. This method is a method in which when handling and transporting containers, etc., they are grouped into a suitable number or weight as a unit, and are handled integrally by equipment without being dismantled on the way.

That is, after a certain number of containers are stacked in multiple rows and in multiple stages on a pallet to form a unit, the containers are packed by shrink wrapping, banding, etc., and then used for cargo handling work.

When containers are stacked in multiple tiers to form a unit, a sheet, ie, a tear sheet, is inserted into each tier for the purpose of stabilizing the containers, preventing cargo from collapsing, and preventing dust.

Conventionally, paper boards have been used as the tear sheets, but they not only have the disadvantage of being impossible to clean and cannot be used repeatedly, but also paper fiber waste gets mixed in when unfilled containers are transported. This is unavoidable and raises concerns that may cause problems later on. In addition, since the material is paper, it is prone to fuzzing, damage, and contamination, making it unhygienic and food-friendly.
Its use is restricted in fields where it collects dust, such as pharmaceuticals.

On the other hand, as a plastic acid tear sheet, a sheet made of a random copolymer of 2 to 10% ethylene and 80 to 98% propylene has been proposed (International Publication No. W
O321018E11).

However, since this tear sheet is made of plastic acid, it is highly charged and tends to attract dust, which can easily cause trouble.

As a typical method for solving the above problems, various methods of adding antistatic agents, carbon black, etc. have been proposed. However, with the above-mentioned method of blending an antistatic agent, when the sheet is washed with water, the antistatic agent is washed away with water, which not only reduces the antistatic effect, but also permanently prevents the antistatic performance. cannot be granted.

In addition, although the method of blending carbon black has an antistatic effect, the sheet becomes completely black, which limits its use in fields that require hygiene, such as pharmaceuticals and foods. Another problem is that it pollutes the extruder and the environment.

[Problem that the invention seeks to solve]

The present invention solves the problems of the conventional technology as described above, and aims to provide a sheet having the following performance in addition to the performance of the conventional tear sheet.

The first objective is to provide a sheet that is highly water resistant, can be used repeatedly, has permanent antistatic properties, and has excellent dustproof effects.

The second object is to provide a sheet with excellent appearance that can be used in fields requiring hygiene such as pharmaceuticals and foods.

The third purpose is to provide a sheet that can be sterilized at high temperatures and that does not warp even during banding or shrink wrapping.

[Means to solve the problem]

The present invention is made by laminating a thermoplastic resin film containing conductive m-fibers on one or both sides of a thermoplastic resin sheet with a thickness of 0.3 to 15 mm, and has a surface resistivity of 1010 Ω or less. This tear sheet has permanent antistatic properties.

The thermoplastic resin sheet of the present invention includes low, medium, and high density polyethylene, polypropylene, polybutene-1, poly-4
- Homopolymers such as methylpentene-1, polyolefin resins such as copolymers containing ethylene or propylene as a main component with other α-olefins, polyamide resins, polyester resins, polyacrylic resins, vinyl chloride It includes single sheets, crosslinked bodies, foams, composites, structures, etc. made of resins, vinylidene chloride resins, saponified ethylene-vinyl acetate copolymers, polyvinyl alcohol resins, and mixtures thereof. .

It has particularly good physical properties such as cold resistance and mechanical strength.
Polyolefin resins, particularly those whose main component is a propylene polymer such as a propylene homopolymer or a block copolymer, are preferred because they are inexpensive.

For example, 50 to 95% by weight of a polypropylene polymer, 5 to 50% by weight of a polyethylene polymer, and the resin component 1
A sheet comprising 0 to 50 parts by weight of an inorganic filler per 00 parts by weight is the most preferred embodiment from the viewpoint of physical properties such as mechanical strength, cold resistance, and heat resistance, and economical efficiency.

The MFR (melt flow rate) of the above propylene polymer is 0.1 to 20 g/10 m1n, and further 0.3 to 15
A range of g/10 m1n is preferred.

When the MFR is less than 0.1 g/10+*in, the fluidity of the molten resin is poor and it is difficult to produce a good sheet.

If it exceeds 20 g/10 m1n, the web of molten resin will sag and good molding will be difficult. Furthermore, there is a concern that the strength and other physical properties of the sheet may deteriorate.

The thermoplastic resin film containing conductive tafIa of the present invention is a film formed by blending conductive fibers with the thermoplastic resin, and has a thickness of 30 to 500 mm, more preferably 50 mm.
A range of 200 to 200 is preferred.

Examples of the conductive fibers include carbon fibers, metal fibers made of aluminum, brass, stainless steel, etc., metallized glass m* made by coating glass fibers with silver, copper, etc.
Examples include synthetic fibers mixed with fine metal powders such as silver, copper, brass, and tin. Among these, carbon fiber is the most preferable in terms of performance and price.

Although either short fibers or long fibers may be used as the Fa male, long fibers are preferable because they have a remarkable effect even when incorporated in a small amount.

The content of the conductive fiber is 5 to 5% relative to the thermoplastic resin.
30% by weight, preferably 7-20% by weight. When the fiber content is less than 5% by weight, the surface resistivity of the sheet is 101.
If the resistance exceeds °Ω, the antistatic effect cannot be satisfied.

If the amount exceeds 30% by weight, the antistatic effect can be achieved, but the sheet becomes dark and the appearance deteriorates.

The tear sheet of the present invention is integrally formed by laminating a thermoplastic resin film containing the conductive fibers on one or both sides of the thermoplastic resin sheet by coextrusion molding or the like. Even if the conductive film is laminated only on one side of such an integrated sheet, charging on the other side can be suppressed (this phenomenon is generally referred to as the tunnel effect).

In addition, in order to facilitate the movement of empty cans during multi-tiered stacking, it is preferable that the front and back surfaces of the sheet have different coefficients of friction.For this purpose, the whole or a desired portion of one side is coated with a method such as embossing or sandblasting. It is desirable to make the surface different by roughening it or by pasting or laminating an anti-slip material such as ethylene-vinyl acetate copolymer or synthetic rubber.

The above coefficient of friction varies depending on the type of metal, glass, or plastic container, the shape of the bottom of the container, the weight of the container, etc., but is generally 0.1 to 0.6 as a static friction coefficient, preferably is suitably in the range of 0.2 to 0.5.

The thickness of the sheet of the present invention is suitably in the range of 0.3 to 15 inches. If the thickness is less than 0.3 mm, the mechanical strength such as rigidity of the sheet will not be sufficient, and if it exceeds 15 mm, the weight of the sheet will increase, which may cause problems in the automation and handling of luggage.

Further, the antistatic performance of the tear sheet of the present invention requires that the surface resistivity be 101°Ω or less. When the surface resistivity exceeds 1010Ω, the antistatic effect is low and dust is easily attracted.

The shape of the tear sheet of the present invention may be any suitable shape such as a rectangle, square, oval, or circle. However, in the case of a shape with corners such as a rectangle or square, a portion of each corner may be shaped to match the shape of the container. It is desirable to add a radius, and it is also possible to form drainage holes at desired locations on the sheet to the extent that required physical properties such as rigidity are not compromised, or to make fine irregularities when forming the sheet to increase the contact area with the container. Adjust the
It is also possible to give directionality when arranging the containers on the tear sheet.

Furthermore, in the present invention, the rigidity, thermal properties, printability, paintability, adhesion, tapping properties, creep resistance, dimensional stability, surface properties (scratch resistance, gloss, flow marks, etc.) of the sheet are improved. For, talc, calcium carbonate,
Additives such as inorganic or organic fillers such as wood flour, flame retardants, antioxidants, ultraviolet absorbers, dispersants, lubricants, crosslinking agents, and organic or inorganic pigments may be added.

〔Example〕

Examples 1 to 3 and Comparative Example 1 Polypropylene polymer (M
F R = 1.0 g/10 m1n, trade name: Nisseki Polypro J120 manufactured by Nippon Petroleum Chemicals Ltd.) and a polypropylene polymer (M F R = 4.0 g/10 m1 n, trade name) as a thermoplastic resin film containing conductive fibers. : Nisseki Polypropylene J130 manufactured by Nippon Petrochemicals Co., Ltd.) and carbon fiber as conductive fiber! a (diameter 7μs, fiber length 140mm)
Three extruders (50 m diameter)
The sheet was supplied to a T-die equipped with m), and the sheet forming conditions were as follows: resin temperature 240°C, cooling roll temperature 70°C, take-up speed 1.5m/sin, with the configuration shown in Table 1, and the thickness was 1.0I.
A tear sheet measuring 11 mm x 500 mm x 600 mm wide was molded.

Table 1 shows the results of surface resistivity, chargeability, half-life of applied voltage, and Ash Te5t using the tear sheet.

Test method> Test conditions = 20°C, 50% RH 1. Surface resistivity: Measured with a tester and insulation resistance meter with an electrode width of 2 cm and a distance between electrodes of 2 cm. 2. Half-life: Measured with an Honest meter (manufactured by Otsuki Shokai). Applied voltage (applied for 20 seconds at 10 mA) 3. Ash Te5t: Rub with cotton gauze 30 times to test adhesion of dried cigarette ash.

Judgment 0: No adhesion at all Δ: A small amount of adhesion Tear sheets were prepared using the following methods, and the evaluation results are shown in Table 1.

Evaluation Results> As is clear from Table 1, it can be seen that the examples within the scope of the present invention have sufficient antistatic performance even when a conductive layer is provided on only one side.

On the other hand, when the carbon fiber content is as low as 4% by weight as in Comparative Example 2, even a three-layer sheet with conductive layers on the front and back sides is insufficient in half-life and Ash Te5t to satisfy antistatic performance. I can't.

:51 The content in parentheses (0) is the carbon fiber content (weight %) [Effects of the invention] As mentioned in F, the tear sheet of the present invention is water resistant, so it can withstand repeated use by washing and is carbon black. Since the permanent antistatic property is imparted without using any of the above, it has excellent appearance and can be suitably used in fields such as pharmaceuticals and foods that require sanitary properties. It also has excellent antistatic performance, so it has a remarkable dust-proofing effect during multi-tier stacking of unfilled containers, transportation, etc.

Furthermore, by incorporating an inorganic filler such as talc, it is possible to improve the rigidity and heat resistance, and these sheets can be easily subjected to high temperature sterilization and shrink packaging.

Patent applicant: Japan Petrochemical Co., Ltd.

Claims (7)

[Claims] (1) It is made by laminating a thermoplastic resin film containing conductive fibers on one or both sides of a thermoplastic resin sheet with a thickness of 0.3 to 15 mm, and has a surface resistivity of 10^1^0Ω or less. Tear sheet with permanent anti-static properties. (2) A tear sheet having permanent antistatic performance according to claim 1, wherein the coefficient of friction on one side of the tear sheet is larger than the coefficient of friction on the other side. (3) A tear sheet having permanent antistatic performance according to claim 1 or 2, wherein the entire or desired portion of at least one side of the tear sheet is roughened. (4) A tear sheet having permanent antistatic performance according to any one of claims 1 to 3, wherein the conductive fibers are carbon fibers. (5) A tear sheet having permanent antistatic performance according to any one of claims 1 to 4, wherein the thermoplastic resin sheet is made of a polyolefin resin. (6) A tear sheet having permanent antistatic performance according to claim 5, wherein the thermoplastic resin sheet has a polypropylene polymer as a main component. (7) A patent claim in which the thermoplastic resin sheet comprises 50 to 95% by weight of a polypropylene polymer, 5 to 50% by weight of a polyethylene polymer, and 0 to 50 parts by weight of an inorganic filler based on 100 parts by weight of the resin component. A tear sheet having permanent antistatic performance as described in item 6.