JPS63265930A - Conductive oriented polyolefin film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a stretched polyolefin film with excellent electrical conductivity, which has been conventionally used in various packaging materials, etc.
High conductivity is imparted to axially stretched polyethylene film, biaxially stretched polypropylene film, etc.

←) Conventional technology It has been known for some time that a method of imparting conductivity to films of thermoplastic resins such as polyolefins involves blending these thermoplastic resins with powders such as conductive carbon black, metals, and metal oxides. There is.

On the other hand, in order to impart conductivity to a stretched film, it is possible to stretch a thermoplastic resin film blended with these conductive powders in uniaxial and biaxial directions, but the stretch breakage occurs and the set stretching ratio is not reached. In addition to not being able to stretch or not being able to obtain sufficient conductivity, which requires a reduction in the amount of conductive powder, there is also the problem that stretching causes a rapid drop in conductivity.

(c) Problems to be Solved by the Invention The present invention has been made to solve the above-mentioned problems of the conductive stretched polyolefin film. It is an object of the present invention to provide a stretched polyolefin film that maintains a high stretching ratio despite being stretched, eliminates a rapid decrease in conductivity due to stretching, and has excellent conductivity as a result.

←) Means for Solving the Problems The conductive stretched polyolefin film of the present invention will be described in detail below. Then, 40% of white conductive powder was prepared by forming a coating layer of tin oxide with antimony solid solution on the surface of white metal oxide powder having a specific surface area of 1 to 10 m"/t.
It is characterized by containing ~1000 parts by weight.

Here, polyolefin refers to ethylene resins such as low-density polyethylene, high-density ethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, polypropylene, propylene-ethylene copolymer, propylene - Refers to propylene resins such as butene-1-ethylene copolymers.

Moreover, the white conductive powder is 1 to 10 rr? / f on the surface of white metal oxide powder such as titanium oxide, silicon oxide, aluminum oxide, zinc oxide, magnesium oxide, etc., preferably 0.1 to 30% by weight, sometimes preferably 1 to 15% by weight. A coating layer is formed of tin oxide in which antimony is dissolved in solid solution.
No. 61-16126, No. 61-39684, No. 61-39685, and No. 61-39686.

In the present invention, the blending ratio of the polyolefin and the white conductive powder is 40 to 1000 parts by weight, preferably 60 to 90 parts by weight, of the white conductive powder per 100 parts by weight of the polyolefin.
It is 0 parts by weight.

If the white conductive powder is less than 40 parts by weight, the stretched film will not exhibit sufficient conductivity, and if it exceeds 1000 parts by weight, it will be difficult to mix into polyolefin and it will not be possible to obtain a film with a high stretching ratio. It happens.

The conductive stretched polyolefin film of the present invention comprises a polyolefin and a white conductive powder, optionally a dispersant,
By further adding plasticizers, coupling agents, stabilizers, colorants, etc.
After heating and kneading with a kneader, mixing roll, etc., it is formed into a film by a known film forming method such as T-die forming or inflation forming, and then the film is stretched uniaxially or biaxially at a normal stretching temperature. It can be obtained by

This stretching method may also be a conventionally known method, for example,
- Axial stretching includes roll stretching in a flat shape, open stretching, and tubular stretching, and biaxial stretching includes tenter stretching in a flat shape, inflation stretching in a tubular shape, mandrel stretching, etc.

Note that the stretching ratio of the stretched film of the present invention is 1 in the -axial direction.
．． It is about 5 to 12 times, preferably about 2 to 10 times,
In the biaxial direction, stretching ratios within this range can be adopted in each of the longitudinal and lateral directions.

Further, it is effective that the stretched film of the present invention is relaxed by heat setting after stretching.

The conductive stretched polyolefin film of the present invention has a thickness of 0.2 to 200μ, preferably 1 to 180μ, and a surface resistivity of 10 to 10Ω.

Further, the stretched film of the present invention can be used as a single layer or in a laminated state with other materials.

(e) Functions and Effects Since the conductive stretched polyolefin film of the present invention uses a specific white conductive powder, it maintains a high stretching ratio even though the conductive powder is blended at a high concentration. Moreover, the rapid decrease in conductivity due to stretching is avoided, and as a result, the conductivity becomes submerged.

(F) Examples Example 1 100 parts by weight of polypropylene (MFR 2,3 tlx o) and 3 tr? / ? A white conductive powder (manufactured by Mitsubishi Metals Corporation, conductive powder 1-W-xj) in which a coating layer consisting of tin oxide containing 10% by weight of antimony is formed on the surface of titanium oxide powder having a specific surface area of 40 parts by weight, 1 part by weight of dispersant (zinc stearate), 0 parts by weight of heat stabilizer (2,6-di-t-butyl-p-cresol)
．． 2 parts by weight were mixed in a super mixer for 2 minutes, melt-kneaded in a twin-screw extruder to form pellets, extruded into a film from an extruder equipped with a T-die, and cooled and solidified to form a pellet with a thickness of 130 μm. The unstretched film was molded.

The surface resistivity of this unstretched film was 4×10 5 Ω.

After that, the unstretched film is stretched by a roll stretching method.
A conductive axially stretched polypropylene film having a thickness of 25 μm was produced by stretching in the longitudinal direction at a stretching temperature of 120° C. and a stretching ratio of 5 times, and then heat setting at a temperature of 120° C. and a relaxation rate of 8%.

The surface resistivity of the obtained film was 8.2×10”Ω.

Example 2 Polypropylene (MFR 2,3ylx o) was used as an intermediate layer, and pellets of the same polypropylene and white conductive powder mixture as in Example 1 were used as both surface layers, coextruded through a T-die, and cooled and solidified. Thickness: 1.5m
A three-layer laminated unstretched film was molded.

The surface resistivity of this unstretched film was 5×1050.

After that, the unstretched film is stretched by a roll stretching method.
By stretching in the longitudinal direction at a stretching temperature of 120 ° C. and a stretching ratio of 5 times, then stretching in the transverse direction at a stretching temperature of 170 ° C. and a stretching ratio of 10 times by a tenter stretching method, and further heat setting in the tenter. A conductive biaxially oriented polypropylene film having a three-layer laminate with each layer thickness of 5μ/20μ15μ was produced.

The surface resistivity of the obtained film was determined to be 3.5×10'Ω.

Comparative Example 1 An unstretched film was formed in the same manner as in Example 1, except that carbon black (Acetylene Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) was used instead of the white conductive powder used in Example 1. However, the dispersion of carbon black was poor and a film could not be formed.

Comparative Example 2 An unstretched sheet was produced in the same manner as in Example 1, except that the same carbon black used in Comparative Example 1 was used in place of the white conductive powder used in Example 1, and the blending amount was 30 parts by weight. The film was molded and then a biaxially stretched film was produced.

The surface resistivity of the unstretched film is 2. OX was 10'Ω, but that of the -axially stretched film was 4.0XIO"
It had decreased to Ω.

Patent applicant: Mitsubishi Yuka Co., Ltd. Representative B Patent Attorney Masahisa Osatani (1 other person)

Claims (1)

[Claims] A polyolefin film stretched at least uniaxially, wherein the polyolefin has a specific surface area of 1 to 10 m^2/g per 100 parts by weight. 40 to 1000 white conductive powder formed with a coating layer made of tin
A conductive stretched polyolefin film characterized by containing part by weight.