JPH0923761A - Agricultural coating film - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide an agricultural coating film which is excellent in antifouling property, hardly causes stains or darkening during use, and can be easily manufactured by a simple process. SOLUTION: The agricultural coating film of the present invention contains 0.01 to 6 parts by weight of polyvinylidene fluoride based on 100 parts by weight of a polyolefin resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural covering film which is used as a covering material for greenhouse cultivation and tunnel cultivation and which has excellent antifouling properties and does not deteriorate in light transmittance even after long-term use.

[0002]

2. Description of the Related Art Conventionally, a synthetic resin film used as a covering material for greenhouse cultivation or tunnel cultivation is apt to be soiled or darkened due to adhesion of mud or dust in the air. The adhered dust is difficult to be removed, and the light transmittance is reduced due to accumulation of stains and darkening with the lapse of the use period, which causes a problem in the growth of agricultural products. As a solution to the above-mentioned problems, Japanese Patent Application Laid-Open No. 59-105031 discloses an agricultural method in which a solution of a fluorine compound or an aqueous emulsion is applied to the surface of a thermoplastic resin film to impart stain resistance and durability. A dressing for use is described.

[0003]

In order to manufacture the product described in the above publication, a step of applying a solution of a fluorine compound or an aqueous emulsion to a once molded thermoplastic resin film and drying it is necessary. Furthermore, if it does not have sufficient adhesiveness to the film surface, it will fall off during use and the effect will decrease, so it is necessary to perform sufficient surface treatment of the film in order to apply it to a film of polyolefin resin with low surface activity. There is.

The present invention solves the above problems of the prior art, is excellent in antifouling property, and is less likely to cause stains or darkening during use.
An object of the present invention is to provide an agricultural coating film which can be easily manufactured by a simple process.

[0005]

The agricultural coating film of the present invention is characterized by containing 0.01 to 6 parts by weight of polyvinylidene fluoride with respect to 100 parts by weight of a polyolefin resin.

Examples of the polyolefin resin in the present invention include low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer and the like, and these can be used alone or in combination of two or more kinds. .
The general formula (CH ₂ —CF ₂ ) _n
0.01 to 6 parts by weight of polyvinylidene fluoride represented by Preferably it is 0.1 to 2 parts by weight. If the amount of polyvinylidene fluoride added is less than 0.01 parts by weight relative to 100 parts by weight of the polyolefin resin, the antifouling property is insufficient, and if it exceeds 6 parts by weight, the antifouling property is sufficient, but The total light transmittance of is significantly reduced.

The polyolefin resin used in the present invention includes stabilizers, antioxidants, plasticizers, stabilizing aids, heat retaining agents, antifogging agents, antifog agents, and ultraviolet rays to the extent that the effects of the present invention are not impaired. You may mix additives, such as an absorbent, a lubricant, and a coloring agent. The above-mentioned heat retaining agent can control the temperature decrease in the house or tunnel covered with the film,
For example, silicon oxide, silicates, phosphates, glass fine powder and the like can be mentioned. The heat insulating agent is added in an amount of 2 to 20 parts by weight, preferably 4 to 100 parts by weight of the polyolefin resin.
10 parts by weight. If the amount of the heat retaining agent is more than 20 parts by weight, the visible light transmittance is remarkably lowered and the strength of the film is also lowered. If the amount is less than 2 parts by weight, the heat retaining effect cannot be obtained.

As the ultraviolet absorber, those of benzophenone type, benzotriazole type, hydroquinone type, salicylic acid type, benzoate type, cyanoacrylate type and the like are preferable. The amount of the ultraviolet absorber added is preferably 0.1 to 5 parts by weight, and more preferably 0.2 to 2 parts by weight, based on 100 parts by weight of the polyolefin resin. If the added amount of the ultraviolet absorber is more than the above, the cost of the film itself becomes high, and if it is too small, the number of pests flying into the house or the tunnel increases, and also the sclerotium disease, wilt disease, mold disease, etc. Spores of pathogenic bacteria are easily formed, which seriously impairs the growth of soft vegetables.

As a method of molding the above polyolefin resin into a film, known methods such as an inflation method, a calender molding method, a T-die molding method and a solution casting method are adopted. If the thickness of the agricultural coating film of the present invention is too thin, the strength will be insufficient, and conversely if it is too thick, it will cause inconvenience in handling in molding work, cutting, joining, spreading work and the like of the formed film. The range of 300 μm is preferable.

[Operation] When the polyolefin resin contains 0.1 to 6 parts by weight of polyvinylidene fluoride,
The surface tension of the resin film, that is, the activity is lowered to make it difficult for dirt to adhere, and even if it adheres, dirt is easily removed and stain resistance is imparted. Therefore, the total light transmittance does not decrease even if it is stretched and used for a long period of time.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1) Ethylene-vinyl acetate copolymer (density: 0.
925 g / cm ³ , MI = 1.4, vinyl acetate content 14
% By weight, hereinafter referred to as "EVA") 1 part by weight of poly (vinylidene fluoride) was added to 100 parts by weight, mixed by a tumbler mixer for 20 minutes, melt-kneaded at 210 ° C by an extruder (40 mmφ), and then extruded. Made into pellets. Resin 10 in which the pellets and EVA are mixed
The following additives were added to 0 part by weight so as to finally have the following contents. That is, 5 parts by weight of hydrotalcite, which is a silicate having the general formula (1) below as a heat retaining agent, and a benzotriazole-based ultraviolet absorber as a UV absorber (trade name “Tinuvin 3” manufactured by Ciba Geigy).
26 ") 0.5 part by weight, and as a hindered amine-based light stabilizer manufactured by Ciba Geigy, trade name" Tinuvin 622 "
0.3 part by weight, 0.3 part by weight of Ciba Geigy's product name “Kimasorb 944”, and 0.1 part by weight of polyvinylidene fluoride. This was molded into a film having a thickness of 100 μm by an inflation molding method.

[0012]

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Example 2 Example 1 was repeated except that the content of polyvinylidene fluoride in the resin was finally 0.8 part by weight.
A film having a thickness of 100 μm was formed in the same manner as in.

Example 3 A film having a thickness of 100 μm was formed in the same manner as in Example 1 except that the content of polyvinylidene fluoride in the resin was changed to 2 parts by weight.

Comparative Example 1 A film having a thickness of 100 μm was formed in the same manner as in Example 1 except that polyvinylidene fluoride was not used, the addition amount of hydrotalcite was 4 parts by weight, and no light stabilizer was added. did.

Comparative Example 2 A film having a thickness of 100 μm was molded in the same manner as in Example 1 except that the content of polyvinylidene fluoride in the resin was changed to 6 parts by weight.

The polyolefin resin films of Examples 1 to 3 and Comparative Examples 1 and 2 were spread on a house in the suburbs of Nagoya, and the surface condition of the film was observed for 3 years from October 1991 to October 1994. Table 1 shows the results.

[0018]

[Table 1]

As can be seen from Table 1, all of Examples 1 to 3 had a high initial total light transmittance, and showed little deterioration even after 3 years and were excellent in antifouling property. However, since Comparative Example 1 does not contain polyvinylidene fluoride, it is inferior in antifouling property, and the light transmittance remarkably decreases with time.
In Comparative Example 2, the amount of polyvinylidene fluoride is too much, so that the light transmittance is low from the initial stage, and it is unsuitable as a covering material for agriculture.

[0020]

EFFECTS OF THE INVENTION The agricultural coating film of the present invention has the above-mentioned constitution, is excellent in antifouling property, is less likely to cause stains or darkening during the period of use, and is easily removed even if it adheres, and therefore is used for a long period of time for spreading. However, the total light transmittance does not decrease. Further, it can be manufactured by the conventional equipment and manufacturing process.

Claims (1)

[Claims] 1. An agricultural coating film comprising 0.01 to 6 parts by weight of polyvinylidene fluoride with respect to 100 parts by weight of a polyolefin resin.