JPH085974B2 - Photodegradable resin film - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a photodegradable resin film, and more particularly to a vinyl chloride resin film that spontaneously undergoes photodegradation upon irradiation with sunlight.

2. Description of the Related Art Films and tapes made of vinyl chloride resin are widely used as various agricultural materials. For example, grafts are widely used in agriculture as described in detail in Japanese Patent Laid-Open No. 61-95072, but this grafting tape has conventionally been used after binding the grafted portions to each other. It was removed manually after 5 months. Therefore, this work requires labor and time, and there is a strong demand for a graft tape that naturally collapses due to irradiation of sunlight for several months.

In order to meet such demand, in addition to the above-mentioned publication,
Japanese Patent Application Laid-Open No. 61-95047 proposes a photodegradable vinyl chloride resin film. These photodegradable films are obtained by mixing an acrylonitrile-butadiene copolymer and an iron compound with a vinyl chloride resin and molding this into a film or tape, but the photodegradability is still insufficient.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention has been made in order to solve the above-mentioned problems in the conventional photodegradable resin film, and has the required physical properties in the initial stage and after a predetermined period of time elapses. Aims to provide a vinyl chloride resin film that rapidly photodegrades in a natural environment.

Means for Solving Problems The photodegradable resin film according to the present invention has a polymerization degree of 600 to 2
100 parts by weight of 500 vinyl chloride homopolymer or copolymer thereof, 5 to 80 parts by weight of a photoreactive compound having 2 or more acryloyl groups or methacryloyl groups in the molecule, 30 parts by weight or less of a diene copolymer, and It is characterized by containing 5 parts by weight or less of a transition metal compound.

In the photodegradable resin film according to the present invention, the base resin is a vinyl chloride homopolymer or a copolymer thereof, and examples of the copolymer monomer component include vinyl acetate, vinyl propionate, and lauric acid. Vinyl esters such as vinyl, acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, diethyl maleate, dibutyl maleate. Maleic acid diesters such as, fumaric acid diethyl, fumaric acid diesters such as dibutyl fumarate, vinyl alkyl ethers such as vinyl methyl ether, vinyl butyl ether, vinyl octyl ether, etc.,
Examples thereof include vinyl cyanides such as acrylonitrile and methacrylonitrile, α-olefins such as ethylene, propylene and styrene, and vinylidene halides such as vinylidene chloride, vinylidene bromide and vinylidene fluoride. These copolymer monomer components are contained in the copolymer in an amount of 30% by weight or less, preferably 20% by weight or less.

Such vinyl chloride homopolymer or copolymer thereof used in the present invention is required to have an average degree of polymerization in the range of 600 to 2500 mainly in order to secure moldability to a film by calendering. Yes, and particularly preferably in the range of 700-1300. When the degree of polymerization is out of the above range, it is difficult to form a film by calendering. However, the processing method of the resin film according to the present invention is not limited.

The photodegradable resin film according to the present invention contains a photoreactive acryloyl group or methacryloyl group in the molecule together with the above vinyl chloride polymer or copolymer.
The photoreactive compound having the above is contained. Examples of such a photoreactive compound include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and dipentaerythritol hexaacrylate. Such photoreactive compounds are
It is contained in the range of 5 to 80 parts by weight with respect to 100 parts by weight of the vinyl chloride polymer or copolymer. When the content of the photoreactive compound is less than 5 parts by weight with respect to 100 parts by weight of the vinyl chloride polymer or its copolymer, the resin film obtained does not have sufficient photodegradability and, on the other hand, 80 When it exceeds the weight part, it becomes difficult to form a film.

When a vinyl chloride polymer or a copolymer thereof containing such a photoreactive compound is formed into a film by calendering or the like, in order to prevent thermal polymerization of the photoreactive compound, the photoreactive compound It is preferable to contain a thermal polymerization inhibitor such as hydroquinone. Furthermore, in order to ensure thermal stability during molding, the resin composition may contain a stabilizer. As such a stabilizer, any stabilizer conventionally used in the production of vinyl chloride resin molded articles can be used, and specific examples thereof include various phosphorus fatty acid salts, rimercaptides, and barium-zinc-based stabilizers. Agents, cadmium-zinc stabilizers, magnesium-zinc stabilizers and the like. These stabilizers are usually used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the vinyl chloride polymer or copolymer.

The resin film according to the present invention may contain a photoreaction initiator in order to accelerate the reaction of the photoreactive compound. As such a photoreaction initiator, any conventionally known one can be used, for example,
Benzyl dimethyl ketal commercially available as “Irgaki Yua 651” (manufactured by Ciba Geigy) can be mentioned as a preferred example. The photoreaction initiator is usually used in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the photoreactive compound.

Further, the photodegradable resin film according to the present invention contains 30 parts by weight or less of a diene copolymer and 5 parts by weight or less of a transition metal compound. Since the diene-based copolymer is relatively easily deteriorated originally, the photo-disintegration property of the resin film is promoted by including the diene-based copolymer in the resin film. In addition, the transition metal compound generally promotes the deterioration of the polymer catalytically. As the diene copolymer,
For example, styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer, acrylonitrile-butadiene copolymer and the like can be mentioned.
Examples of the transition metal compound include iron, manganese, copper,
Although various inorganic compounds and organic compounds such as cobalt are included, transition metal salts of organic acids such as cobalt stearate can be preferably used.

Further, the photodegradable resin film according to the present invention may contain any plasticizer conventionally used for producing a molded product of vinyl chloride resin. Specific examples of such plasticizers include dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, di-2-ethylhexyl phthalate, octyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate, and higher alcohol phthalates. Phthalates such as acid esters, trimellitic acid such as tri-2-ethylhexyl trimellitate, di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, dibutyl sebacate, di-2-ethylhexyl sebacate, etc. Fatty acid ester type, phosphoric acid tri-2-
Examples thereof include phosphoric acid ester type such as ethylhexyl and tricresyl phosphate, and further polyester type plasticizers and epoxidized soybean oil.

These plasticizers are not particularly limited, but are usually added in an amount of 100 parts by weight or less with respect to 100 parts by weight of the vinyl chloride polymer or its copolymer.

The photodegradable resin film according to the present invention can be obtained by molding the above components into a film by a usual method. Usually, calendering is preferable, but a sol method, an extrusion method or the like can also be used. In the present invention, the film also includes a tape, and the thickness thereof is usually preferably in the range of 20 to 500 μm.

The present invention is by no means limited by the mechanism by which the resin film undergoes photodegradation, but the photoreactive compound is polymerized in the resin film by irradiation with light or becomes a polymer in the resin film. As a result of cross-linking copolymerization, the resin film increases in hardness, for several months, after being left in a natural environment, for example, by applying an external force such as a slight bending, or It is easily destroyed by wind and rain.

Effects of the Invention As described above, the photodegradable resin film according to the present invention contains a diene copolymer and a transition metal compound together with a photoreactive compound, and further preferably contains a photoreaction initiator, Under natural environmental conditions in which sunlight is present, usually after 3 to 5 months, it easily collapses by applying an external force such as touching with hands or by wind and rain.
Therefore, as described above, when the tape made of the resin film according to the present invention is used as the grafting tape, the grafting tape can be easily removed without the trouble of manually untiing the knot.

EXAMPLES The photo-disintegrating main film according to the present invention will be specifically described below with reference to examples.

Example 1 100 parts by weight of polyvinyl chloride (average degree of polymerization: 1100), Ba-Z
1.5 parts by weight of n-based stabilizer, 20 parts by weight of phthalic acid, 30 parts by weight of trimethylolpropane triacrylate, 0.3 part by weight of photoinitiator "Irgakiure 651" (containing 400 ppm of hydroquinone as a thermal polymerization inhibitor), styrene. A mixture of 10 parts by weight of butadiene-styrene block copolymer and 2 parts by weight of cobalt stearate was calendered into a film having a thickness of 100 μm.

This film was irradiated with ultraviolet rays using a weather resistance tester “Yubcon” to evaluate the photodegradability of the film. After irradiation for 50 to 100 hours, the film started to become hard, and after irradiation for 150 hours, the film was hard and brittle, and easily disintegrated by applying slight bending. Such UV irradiation for 150 hours is said to correspond to a state of being left for 3 to 4 months in a natural environment.

Claims (2)

[Claims] 1. A vinyl chloride homopolymer having a degree of polymerization of 600 to 2500 or 100 parts by weight thereof, 5 to 80 parts by weight of a photoreactive compound having two or more acryloyl groups or methacryloyl groups in the molecule, and a diene. A photodegradable resin film containing 30 parts by weight or less of a copolymer and 5 parts by weight or less of a transition metal compound. 2. The photodegradable resin film according to claim 1, which contains a photoreaction initiator.