JPS58120657A - Non-rigid vinyl chloride resin film for agriculture - Google Patents

Abstract

PURPOSE:The titled film having improved transparency and low shrinkage, obtained by blending vinyl chloride resin with inert solid fine particles whose fine pores are filled with an additive for vinyl chloride resin, followed by making the blend into a film. CONSTITUTION:Fine pores of inert solid fine particles are previously filled with an additive for vinyl chloride resin until no occurrence of bubbles is observed when they are immersed in a polypropylene glycol bath heated at 160 deg.C, 100pts.wt. vinyl chloride resin is blended with 0.05-10pts.wt. inert solid fine particles, and made into a film. A plasticizer, a stabilizer, etc. is used as the additive for filling the fine pores, it is melted or dissolved in a solvent and processed into a solution, and it is blended with the inert solid fine particles by a mixer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a soft vinyl chloride resin film for agricultural use,
More specifically, the present invention relates to an agricultural soft vinyl chloride resin film containing inert solid fine particles that has good transparency and little shrinkage.

In recent years, energy conservation has become a big issue in greenhouse horticulture, and as a result, the expansion film for greenhouses has been double-layered,
Triple coating (multilayer coating) provides heat retention, and the method is changing to one that does not use the conventional heating device.

Soft vinyl chloride resin films are overwhelmingly widely used as such stretching coating films, but since soft vinyl chloride resin films tend to flop at high temperatures,
When used in multiple layers in this manner, the films tend to stick together, resulting in extremely poor workability. Therefore, various methods have been proposed to reduce the adhesion of this soft vinyl chloride film. Among them, inert solid particles such as calcium carbonate, clay, silica, and talc are kneaded into the raw resin to form a film. This method is highly effective.

However, soft vinyl chloride films made by kneading such inert solid fine particles tend to (1) have a large amount of fine (about 1 mlφ in diameter) bubble-like spots formed over the entire surface of the film; ii) 4) Vinyl houses have the disadvantage of shrinking significantly when expanded.

(1) If there are many bubble-like spots on the film surface, the transparency will be impaired and the transmittance of the useful solar rays will be reduced, which will have a negative impact on cultivated crops. If the film shrinks significantly during stretching, the coating may not be completely applied or the film may be torn, both of which are fatal drawbacks for agricultural films.

The inventors of the present invention have made extensive studies in view of the above points, and have found that the drawback in film quality containing the above-mentioned inert solid fine particles is that the inert solid fine particles are porous and have pores. As a result of further investigation, we found that the above drawbacks can be solved by filling the pore spaces of the inert solid particles with an additive for soft vinyl chloride resin before adding it. They also discovered this and completed the present invention.

That is, according to the present invention, the pores of the inert solid fine particles are filled with an additive for vinyl chloride resin until almost no bubbles are observed when immersed in a polypropylene glycol bath heated to 160°C, and then the pores are filled with an additive for vinyl chloride resin. A soft vinyl chloride resin film for agricultural use containing inert solid fine particles is formed by forming a film from a resin composition blended with vinyl resin.

is provided.

The present invention will be explained in detail below.

The inert solid fine particles in the present invention are inorganic fine particles having a particle size of about 0.01 to 30 μm, such as calcium carbonate, magnesium carbonate, clay (aluminum silicate hydrate), silica, talc (magnesium silicate), etc. hydrate), calcium silicate, titanium dioxide, barium sulfate, etc. These may be obtained by mechanically pulverizing naturally occurring minerals as they are, or may be artificially synthesized by a precipitation method, thermal decomposition method, acid decomposition method, or the like.

These inert solid fine particles are added to the vinyl chloride resin in an amount of about 0.05 to 10.0 parts by weight per 100 parts by weight of the vinyl chloride resin, and mixed with other additives for the vinyl chloride resin.

In the present invention, the pores of such inert solid fine particles are filled with an additive for vinyl chloride resin before adding them to the vinyl chloride resin.

Additives for this filling include, for example, plasticizers,
Any of the usual additives for soft vinyl chloride resins such as stabilizers, surfactants, and lubricants can be used, and these may be used alone or in combination of two or more. As a plasticizer,
For example, phthalic acid derivatives such as moro-octyl phthalate and di(2-ethylhexyl) phthalate, isophthalic acid derivatives, adipic acid derivatives, phosphoric acid derivatives such as tricresyl phosphate and tricylenyl phosphate, various epoxy Examples include compounds. Examples of the stabilizer include metal soaps such as calcium stearate, barium stearate, zinc stearate, and phosphite esters. Examples of the surfactant include nonionic surfactants and ionic surfactants such as nrubitan ester and diglycerin ester. Examples of the lubricant include polyethylene wax, liquid paraffin, fatty acid amides, and the like.

Although the method of filling the pores of the inert solid fine particles with the above-mentioned additive for soft vinyl chloride resin is arbitrary, since the solid fine particles have good affinity or wettability with the resin additive, it is possible to fill the pores of the inert solid particles with the additive for the resin. Just enough contact with the resin additive fills the pores with the additive. Specifically, the additive is melted or dissolved in another solvent to form a solution,
In short, it can be made into a liquid and then blended with inert solid particles using a conventional mixer or blender such as a Henschel mixer, Banbury mixer, or ribbon blender.

In this case, the solvent used is one that dissolves the additive,
It is desirable to use something that does not dissolve the vinyl chloride resin. For example, when using the surfactant sorbitan monopalmitate as an additive, methanol, ethanol, isopropanol, benzene, etc. may be used, and the lubricant methylene bisstearate may be used. When using Roamide, butanol, xylene, etc. may be used.

When filling the additive in a molten state, the filling temperature may be appropriately selected at a temperature higher than the melting point of the additive, and is usually 20 to 18
0°C is desirable. Further, when filling in a solution state, there is no particular temperature restriction, but it is usually preferable for operation to fill at a temperature below the boiling point of the solvent used. In addition, in the case of solution filling, if it is undesirable for the solvent used to mix with the vinyl chloride resin, it is necessary to remove the solvent by evaporating it from the solid particles by hot air drying, infrared drying, etc. after filling. be.

In addition, the time required for filling may vary depending on the weight of the inert solid particles to be treated, the type of resin additive, whether the filling is in a molten state or a solution state, the type of mixer used, etc., but normally It takes about 10 minutes to 2 hours.

In the present invention, as described above, the pores of the inert solid particles are filled in advance with an additive for vinyl chloride resin. When immersed in a heated polypropylene glycol bath, it is necessary to do so until the generation of bubbles is almost no longer observed.

If foaming is observed in the polypropylene glycol bath, this indicates that the pores of the solid particles have not yet been sufficiently filled. As shown in the example, a large number of bubble-like specks are generated on the film surface, and the film also shrinks significantly when stretched on vinyl.

In actual operation, during filling, from the mixer,
A small amount of solid fine particles may be appropriately collected, and filling may be performed while checking the foaming state in a polypropylene glycol bath, and the blending operation may be continued until foaming is hardly observed.

The amount of resin additive required to fill the pores of the inert solid particles until foaming is no longer observed varies depending on the type, pore volume, pore diameter, apparent specific gravity, etc. of the solid particles. liquid, but usually about 100 inert solid particles
About 10 to 200 parts by weight per part is sufficient. Of course, there is nothing wrong with adding more than that.

The vinyl chloride resin used in the present invention includes vinyl chloride homopolymers; copolymers mainly composed of vinyl chloride with other vinyl monomers, such as vinyl acetate, vinylidene chloride, diethyl maleate, ethylene, and propylene. copolymers with the like; blends thereof; and blends of these with other polymers, among which vinyl chloride polymers are preferred.

The film of the present invention is produced by blending inert solid fine particles whose pores are filled in advance with the vinyl chloride resin additive as described above into the vinyl chloride resin, and further including a plasticizer, a stabilizer, a surfactant, and a lubricant. A resin composition is prepared by adding additives such as the like, and is produced into a film with a thickness of about 30 to 200 μm by a known film forming method such as melt extrusion method, solution casting method, calender method, etc. easily obtained.

In addition, it is essential that the film of the present invention contains at least a plasticizer as an additive, and vinyl chloride resin 10
About 30 to 60 parts are blended with respect to 0 parts.

Next, the present invention will be explained with reference to examples.

(Example) (1) Inert solid fine particles C, E, H shown in Table 1 were added with an additive for vinyl chloride resin and blended in a Henschel mixer to fill the pores. I got it.

Mata, 20% of sorbitan monopalmitate in ethanol
% solution and similarly filled with a Henschel mixer.
Solid fine particles F were obtained by drying at 50° C. for 20 minutes under reduced pressure of ilIIg.

It was confirmed that almost no bubbles were generated when these samples were immersed in a polypropylene glycol bath heated to 160°C.

(2) The following composition was obtained by adding the additive-filled inert solid fine particles thus obtained in the amounts shown in Table 2.

Vinyl chloride resin (P=1300) 100 parts DO
P (dioctyl phthalate) 50 Epoxy resin 15 Barium stearate 05 Zinc
15〃(3) After preliminary kneading the above resin composition with two rolls, use a calendar method! Films C', E', F', H' having a thickness of +50μ were obtained.

Table 2 shows the results of measuring the obtained film for (1) number of bubble-like spots, (2) transparency (degree of haze), (2) shrinkage rate, and (2) degree of adhesion.

(Comparative example) Inert solid fine particles B, D, and G were filled with an additive for vinyl chloride resin to such an extent that bubble generation was observed in polypropylene glycol, and fine particles A were not filled at all. As a result of conducting the same test as in the example, money plan 1
Table 2.

As is clear from the above Examples and Comparative Examples, the agricultural soft vinyl chloride resin film provided by the present invention has the following advantages: It has good transparency with almost no foamy spots, and (11) has little shrinkage when expanded, making it extremely useful in the agricultural field.

In addition, inert solid fine particles such as calcium carbonate are light and easily scattered and become dust, so when they are kneaded into a film, the dust of solid fine particles is thrown up on the - side, which also poses a problem in terms of occupational health and environment. However, the inert solid fine particles of the present invention whose pores are filled with a resin additive are desirable from the viewpoint of environmental hygiene because such dusting hardly occurs.

patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] (1) After filling the pores of the inert solid particles with an additive for vinyl chloride resin until almost no bubbles are observed when immersed in a polypropylene glycol bath heated to 160°C, An agricultural soft vinyl chloride resin film containing inert solid fine particles formed by forming a film from a resin composition blended with.