JPS5950174B2 - Method for producing agricultural soft vinyl chloride resin film or sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a vinyl chloride fat-based film or sheet suitable for agricultural use, which has improved properties by using tannins.

Conventionally, when synthetic resin films or sheets using tannins (hereinafter abbreviated as T agents) are used as agricultural heat insulating materials, they are useful for protecting crops and fruits, increasing production, accelerating ripening, improving taste, and preventing pests and diseases. is known (see Japanese Patent No. 49504 and Japanese Patent No. 468324).

Conventionally, the method of using agent T in a synthetic resin film or sheet (hereinafter abbreviated as film) includes (1) manufacturing a film in advance, and then dipping this film into an alcoholic or aqueous solution of agent T. Method of applying, dipping or spraying.

(2) A method in which the synthetic resin powder is immersed or sprayed in an alcoholic or aqueous solution of the T agent, and then formed into a τ film using a normal method, or (3) The T agent alone is added to the synthetic resin powder. Alternatively, a method is known in which an alcohol solution is mixed into a container and then formed into a film using a conventional method.

However, among these conventional methods, methods (1) and (2) have complicated steps [method (1) is film formation → coating or dipping → drying; method (2) is powder → dipping → drying; method (2) is powder → dipping → drying; Wash with water→
dehydration → drying → film formation], and industrially (3)
This method is considered to be better. However, when mixing the T agent with the resin powder in method (3), (a) If the T agent is mixed alone with the synthetic resin powder, a small amount of the T agent (up to 10/1000 in weight ratio) is mixed into a large amount of the resin powder. : Normally 0.1~2/1000
) is difficult to mechanically mix, and the resulting film has poor transparency and rough surfaces due to insufficient dispersion of the T agent. When mixing in an alcohol bath solution with resin powder, a small amount of alcohol will not contribute to the dispersibility of the T agent, and a tight dispersion will not be obtained unless the alcohol is used in an amount at least 15 to 20 times the amount of the T agent. .

Most of the alcohol used is released into the atmosphere during the mixing and film forming steps, but releasing a large amount of alcohol not only wastes resources but is also unfavorable from a hygiene and safety standpoint. If used as an aqueous solution, the film may foam during the film forming process, and if the raw material synthetic resin is polyvinyl chloride resin, there may be adverse effects such as hydrolysis of compounding aids contained in the resin. There were also problems when using it as an aqueous solution.

In view of the above-mentioned circumstances, the inventors of the present invention have conducted intensive research into a method for uniformly dispersing the T agent in a film made of synthetic resin, particularly soft polyvinyl chloride resin, and have found that the alcohol solution of the T agent is phosphoric acid. This phosphoric acid ester dissolves very well in the T-based ester and dissolves the alcoholic solution of the T agent in it.Additionally, this phosphoric acid ester is mixed and blended with vinyl chloride resin powder and auxiliary agents such as plasticizers and stabilizers to form the current resin composition. They discovered that the mixture can be mixed well and homogeneously, and completed the present invention.

That is, in the present invention, an alcohol solution of the T agent dissolved in one or two alcohols selected from alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, etc. is added to the phosphoric acid ester, and after dissolution. The gist of the present invention is to mold a resin composition in which the obtained phosphoric acid ester mixture is blended with a vinyl chloride resin into a film.To explain the present invention in more detail, the raw material vinyl chloride in the present invention The system resin (hereinafter abbreviated as PVC) includes polyvinyl chloride, vinyl chloride and other monomers,
For example, copolymers of acetate, ethylene, propylene, alkyl vinyl ethers, acrylic esters, methacrylic esters, acrylonitrile, etc., polyvinyl chloride or the above polyvinyl chloride copolymers and chlorinated polyethylene, chlorinated polypropylene, chlorinated Polymer blends with chlorine-containing polymers or copolymers such as polyisoprene may be mentioned.

The present invention is not affected in any way by the type and degree of polymerization of the above resin.

A commercially available T agent may be used as it is, but if necessary, it may be purified before use.

The amount of T agent used is 0.0 per weight of PVClOO.
1 to 1.0 parts by weight are suitable for achieving the objectives of the present invention. As for the alcohol, saturated monohydric alcohols with a relatively small number of carbon atoms, such as methyl alcohol, ethyl alcohol, and allopyl alcohol, are recommended from the viewpoint of solubility of the T agent, vapor pressure, cost, safety and health, etc. These are listed as suitable materials, and these can be used alone or in combination of two or more types. The amount of alcohol used is such that the T agent is sufficiently dissolved and when mixed with the phosphoric ester, it is dissolved. It is necessary that the T agent does not precipitate, and the amount of alcohol used should be approximately 1/2 part by weight or more of the T agent, and the amount of alcohol used is small, 1/2 part by weight or less of the T agent. However, since the T agent has a large specific volume, the dissolution operation becomes complicated, which is not preferable.

There is no particular upper limit to the amount of alcohol used, and using too much alcohol is undesirable from economical, safety, and sanitary points of view, and the preferred range is from the equivalent weight part to 5 times the weight of the T agent. be. Examples of phosphoric acid esters include tricresyl phosphate (hereinafter abbreviated as TCP); tricylenyl phosphate, tributyl phosphate, triethyl phosphate, 2-ethylhexyl diphenyl phosphate, and cresyl phosphate. Preferred examples include dildiphenyl phosphate and the like, and these can be used alone or in combination of two or more.

The amount of phosphoric acid ester used is not particularly related to the amount of T agent used, but if the amount used is small, the dispersion of the T agent will be poor, so it is recommended to use at least 0.5 parts by weight per part by weight of PVClOO. Good.

As the plasticizer to be added to PVC, plasticizers that are usually added to PVC can be used, such as di2 phthalate.
- Ethyl, hexyl (abbreviated as DOP), diisodecyl phthalate, and butylbenzyl phthalate; examples of aliphatic dibasic acid esters include phthalate ester plasticizers such as dioctyl adipate and dioctyl sebacate; and diethylene glycol dibenzoate. Examples of plasticizers include glycol ester plasticizers and fatty acid ester plasticizers such as butyl oleate, and other plasticizers include trioctyl trimellitate, chlorinated paraffin, and alkylbenzene. These plasticizers may be used alone or in combination. The amount of plasticizer is
The amount of plasticizer is preferably about 20 to 70 parts by weight based on the weight part of PVClOO used as the raw material. If the amount of plasticizer is less than 20 parts by weight, it is impossible to obtain a film that is sufficiently flexible to be stretched and used as an agricultural film. If the amount of plasticized resin exceeds 70 parts by weight, the film becomes too soft and its mechanical strength decreases, and the film itself becomes sticky, which is not preferable. It goes without saying that, in addition to the above-mentioned plasticizer, PVC may further contain additional additives such as a stabilizer, a lubricant, and a coloring agent.

In order to obtain a flexible PVC film for agriculture according to the present invention, the T agent is first completely dissolved in alcohol containing 1/2 part by weight or more of the T agent, and then added to the phosphoric acid ester and stirred to form a uniform solution. This solution is added to a mixture of PVC and additives such as plasticizers, stabilizers, colorants, etc., and the solution is mixed using a conventional method, that is, a commonly known compounding machine such as a lipon blender. After stirring and mixing, use a Banbury mixer, a calender roll, or an extrusion molding plate, etc.
It can be easily used to form a film.

Compared to films obtained by conventional methods, the film obtained by the method of the present invention has excellent dispersion of the T agent, excellent transparency, and has an excellent appearance with no roughness on the surface of the product. , 2. The effects of the T agent blended with Agricultural products and fruits, such as protection and ripening promotion, are superior to those produced by conventional methods, and the alcohol used during production is Since only a small amount is required compared to conventional production methods, it is preferable in terms of resource saving and safety and health, and its industrial value is great.

In order to better understand the method of the present invention, Examples will be described below, but it goes without saying that the present invention is not limited to these Examples. Example 1 Four types of films, A, B, C, and D, were prepared by changing the order of addition of the T agent to the following formulations, and the transparency and outer sharpness of the films were compared.

Note) PVC: vinyl chloride homopolymer (average degree of polymerization 1050
) Film A: 0.1 part by weight of T agent and 0 methyl alcohol
．． Dissolve in 1 heavy Dobe (same weight as T agent) and add 3 times more.
In addition to parts by weight of TCP, a homogeneous solution was made by stirring and gradually added to the above premixed mixture while stirring, dry-up, and then formed into a film using a sword renderer to a thickness of 0.1 m/m. He became a master of film.

Film B: 3 parts by weight of TCP was added in advance to the above formulation and an alcohol solution prepared by dissolving 0.1 part by weight of T agent in 2 parts by weight of methyl alcohol (20 times the amount of T agent) was added to the mixture while stirring. In addition, after drying, a film with a thickness of 0.1 m/m was produced using a calender device.

Film C: A film was formed under exactly the same conditions as when film B was formed, except that the amount of methyl alcohol used was reduced from 2 parts by weight to 0.1 parts by weight (same weight as the T agent). I got a C.

Film D: Film D was produced under the same conditions as those used to produce Film B, except that no methyl alcohol was used and the T agent was used as it was.

FIG. 1 shows the results of measuring the light transmission characteristics according to wavelength for the above four types of films A to D.

As can be seen from Fig. 1, film A (produced by the method of the present invention) is
Compared to the outer films B, C, and D, the absorption in the ultraviolet region is deep (absorbs well), and the transmittance is high in the visible region, indicating that visible light is transmitted well. This shows that the particles are more evenly distributed than the outer film. Also, film A had the best appearance, whereas films C and D had rough film surfaces, indicating poor dispersion of the T agent. In addition to the above Example 1, almost the same results as in the above Example 1 were obtained even when ethyl alcohol was used in place of the methyl alcohol used in Example 1, and even when the blending recipe was changed. It can be seen that the method of the present invention is superior to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing wavelength-specific light transmission curves of four types of films prepared by changing the addition and blending order of the T agent. Film A: Film produced by the method of the present invention, Film B
, C, D: Films for comparison.

Claims (1)

[Claims] 1 An alcoholic solution of tannins dissolved in one or more alcohols selected from alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, etc. is added to the phosphoric acid ester, and after dissolving, the obtained 1. A method for producing a flexible vinyl chloride resin film or sheet for agricultural use, which comprises molding a resin composition in which a phosphoric acid ester mixture is blended into a vinyl chloride resin into a film or sheet.