JPH0762154A - Pliable film - Google Patents

Abstract

PURPOSE:To obtain the title film which is pliable, has moderate stretchability and strength, is excellent in relaxation of stress, and does not generate a harmful gas, e.g. chlorine, during burning. CONSTITUTION:The film is made of a composition comprising 75-25wt.% polyolefin and 25-75wt.% hydrogenated copolymer comprising 5-50wt.% styrene units and 95-50wt.% diene units.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible film, particularly a bandage film for sticking to an affected area or fixing something on the skin of a patient, and more particularly to a film for a first-aid bandage.

[0002]

2. Description of the Related Art Conventionally, films such as adhesive plaster films which are required to have flexibility have been prepared by applying an adhesive to a base film made of a plastic such as soft polyvinyl chloride or polyolefin. , Soft polyvinyl chloride film is often used. However, since the soft polyvinyl chloride film contains a large amount of a plasticizer, the exudation of the plasticizer causes a decrease in the adhesive strength, so that treatment with an anchor coating agent is necessary. Further, since polyvinyl chloride generates harmful chlorine-based gas when incinerated, its use tends to be restricted worldwide.

On the other hand, a polyolefin film such as polyethylene or polypropylene, or Japanese Patent Publication No.
Although a film composed of olefin-based and diene-based elastomers disclosed in Japanese Patent Publication No. 27424 is considered as a substitute material for polyvinyl chloride, the polyvinyl chloride base material was used because of its unbalanced flexibility, elongation and stress relaxation property. There was a problem of tightness and discomfort when applied to the affected area, as compared with the adhesive plaster film. That is, in a film made of a conventional olefin-based and diene-based elastomer, the flexibility and the stress relaxation property are contradictory to each other. If the elastomer ratio increases, the flexibility increases, but the stress relaxation property decreases and the elastomer ratio decreases. For example, the stress relaxation property is improved, but the flexibility is decreased.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, does not require treatment of an anchor coating agent for preventing migration of plasticizer, does not generate harmful gas during combustion,
It is an object of the present invention to provide a flexible film having appropriate stress relaxation property, flexibility and strong elongation.

[0005]

The present invention is based on styrene 5-5.
A flexible film having a composition of 25 to 75% by weight of a hydrogenated product of a copolymer of 50% by weight and 95 to 50% by weight of a diene hydrocarbon, and 75 to 25% by weight of a polyolefin. As the diene hydrocarbon, isoprene,
Butadiene, etc. may be mentioned.

The flexible film of the present invention is characterized by containing a styrene skeleton in the constituent material so as to provide flexibility and stress relaxation properties without adding a plasticizer. The hydrogenated product of a copolymer of styrene and a diene hydrocarbon has a styrene content of 5 to 50% by weight and a melt flow rate (MFR) of ASTM D1238; 23.
It is preferably 2 to 10 g / 10 minutes at 0 ° C. and 2.16 kg.
When the styrene content is less than 5%, the stress relaxation property decreases, 5
If it exceeds 0%, the flexibility tends to decrease. In a film particularly required to have flexibility such as a medical bandage, a bandage film, and a film for a first-aid bandage, the copolymer of styrene and a diene hydrocarbon is preferably a flexible random copolymer.

As the polyolefin, polypropylene, polyethylene, a high α-olefin resin which is a copolymer of ethylene and α-olefin, an ionomer resin having a metal ion bond between polymer chains containing ethylene as a main component, ethylene and methyl are used. Examples thereof include copolymers of methacrylate, and MFR of ASTM D1238; 23.
2-60g / 10min at 0 ℃, 2.16kg or ASTM D
1238; 190 ° C., 2.16 kg, 0.1 to 20 g / 10 minutes are preferable.

When the hydrogenated product of the copolymer of styrene and diene in the film composition is less than 25% by weight or the polyolefin is more than 75% by weight, the flexibility is lowered to give a hard film which is applied to the skin. The feeling of strangeness when doing is increased. On the other hand, when the hydrogenated product of the copolymer of styrene and diene exceeds 75% by weight or the content of polyolefin is less than 25% by weight, the stress relaxation property decreases,
After sticking, the tightening on the affected area becomes large, and it is not suitable as a film base material for bandages.

The film of the present invention can be formed into a film after melt-kneading the above hydrogenated product of a copolymer of styrene and a diene and polyolefin. The method of film formation is
Known methods such as the inflation method and the T-die method are used. The thickness of the film is appropriately selected depending on the required strength and elongation, flexibility, etc., but is usually about 30 to 200 μm.

To the film of the present invention, if necessary, lubricants and fillers such as talc, stearic acid amide, calcium stearate, titanium oxide, etc., or antioxidants, ultraviolet absorbers, etc. may be appropriately added to the above composition. You can
The film of the present invention preferably has a longitudinal stress relaxation rate of 30% or more and a flexibility of 2 or more, and a lateral stress relaxation rate of 35% or more and a flexibility of 2 or more.

The film of the present invention is subjected to corona discharge treatment for improving printability during or after the film forming process, or perforation processing for improving air permeability, and further embossing on the surface. May be given. When used in a plaster, a backside coated with an adhesive and a film such as gauze or release paper is used. Less than,
A more specific description will be given with reference to examples.

[0012]

【Example】

Examples 1 to 7 A hydrogenated product of a random copolymer of styrene and a diene, a polyolefin, and a lubricant were mixed in the proportions shown in Table 1, and 180
After melt-kneading at ~ 220 ℃, T at 200 ~ 230 ℃
A film having a thickness of 90 μm was formed by a die film forming machine. Table 2 shows the results of measuring the flexibility, the stress relaxation rate, the tensile strength, the elongation, and the elastic modulus in the machine direction and the transverse direction of the film, respectively.

Flexibility A sample having an initial length of 50 mm and a width of 18 mm is pulled at a tension rate of 200 mm /
It is the value of 50% modulus divided by 5% modulus when pulled in minutes. Stress relaxation rate Sample with initial length of 50 mm and width of 18 mm is pulled at 200 mm /
When pulled to 50% of the initial sample length in minutes,
It is the ratio of the stress relaxed after 1 minute to the initial stress. Tensile strength This is the breaking stress when a sample with a length of 50 mm and a width of 10 mm is pulled at a pulling speed of 300 mm / min. Elongation This is the elongation at break when a sample with a length of 50 mm and a width of 10 mm is pulled at a pulling speed of 300 mm / min. Elastic modulus This is the initial elastic modulus when a sample with a length of 50 mm and a width of 10 mm is pulled at a pulling speed of 300 mm / min.

Comparative Examples 1 to 5 A hydrogenated product of a random copolymer of styrene and a diene and a polyolefin were blended in the proportions shown in Table 1, and 180 to 22 were added.
After melt-kneading at 0 ° C., a film having a thickness of 90 μm was formed by a T-die film forming machine at 200 to 230 ° C. The flexibility, the stress relaxation rate, the tensile strength, and the longitudinal strength of the film were measured in the same manner as in Examples 1 to 7 in the longitudinal and transverse directions, respectively.
The results of measuring elongation and elastic modulus are shown in Table 2.

[0015]

[Table 1]

[0016]

[Table 2]

As is clear from Examples 1 to 7, hydrogenated products of random copolymers of styrene and diene 25 to 75
A film composed of 50% by weight and a polyolefin of 75 to 25% by weight is flexible, exhibits appropriate elongation and strength, and is also excellent in stress relaxation property. When the hydrogenated product of the random copolymer of styrene and diene is less than 25% by weight or more than 75% by weight as in Comparative Examples 1 and 2, the random copolymerization of styrene and diene as in Comparative Examples 3 and 5 is performed. In the case of an olefin-based and diene-based elastomer film that does not use a combined hydrogenated product, the flexibility and the stress relaxation property cannot be balanced, and it is not suitable as a flexible film.

[0018]

EFFECT OF THE INVENTION The film of the present invention is flexible, has appropriate elongation and strength, is excellent in stress relaxation property, and does not generate toxic gases such as chlorine during combustion.

Front Page Continuation (72) Inventor Toshiaki Takatsu 2-4-4 Kudan Minami 2-chome, Chiyoda-ku, Tokyo Nichiban Co., Ltd.

Claims (2)

[Claims] 1. A hydrogenated product 2 of a copolymer comprising 5 to 50% by weight of styrene and 95 to 50% by weight of a diene hydrocarbon.
A flexible film having a composition of 5 to 75% by weight and a polyolefin of 75 to 25% by weight. 2. The film according to claim 1, which has a longitudinal stress relaxation rate of 30% or more and a flexibility of 2 or more, and a lateral stress relaxation rate of 35% or more and a flexibility of 2 or more.