JPS6050378B2 - Covering material for greenhouse horticulture - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a covering material for greenhouse horticulture that can reduce the occurrence of haze.

In recent years, greenhouse cultivation has enabled a stable supply of various vegetables and fruit trees throughout the year.

Polyvinyl chloride films are widely used as covering materials for greenhouse horticulture and are used in the largest quantities. This is because polyvinyl chloride-based resins have excellent features in terms of weather resistance and transparency, as well as from an economic standpoint. The original purpose of a greenhouse is to maintain the temperature essential for the growth of cultivated crops, that is, to keep them warm. In order to improve heat retention, it is necessary to improve the degree of sealing of the greenhouse and suppress the amount of heat escaping through ventilation. Recently, with the trend toward energy conservation in particular, management techniques have been implemented to make greenhouses as tightly sealed as possible in order to effectively utilize solar energy without adversely affecting the crops inside the greenhouse. It is coming.

By implementing this management technique, the environment inside the greenhouse tends to become more humid than before, and at the same time, there is a problem in that the amount of mist (also called fog) that occurs within the temperature increases significantly. Moya is said to be closely related to pests and diseases of cultivated crops or to the quality of harvested products, and must be avoided as much as possible in greenhouse cultivation. Moya is basically caused by the condensation of water vapor inside the greenhouse, and is a phenomenon that often occurs in the morning and evening when the temperature difference inside and outside the greenhouse changes rapidly.

Haze can be eliminated by ventilating the air inside and outside the greenhouse. However, in general, as emphasis is placed on temperature retention, ventilation is often not possible, which has been a size issue in greenhouse cultivation. Since the occurrence of mist is essentially a J phenomenon caused by moisture within the greenhouse, the occurrence of mist can be reduced by reducing the amount of moisture supplied to the atmosphere within the greenhouse.

One way to prevent the occurrence of haze is to cover the inside and surface of the greenhouse with mulch material. However, covering with mulch material is not necessarily an advantageous method for greenhouse growers because not only is the covering work complicated, but the cost of materials is also high. Another countermeasure against haze, that is, a method of reducing the occurrence of haze by improving coating materials, has been proposed by adding an organic siloxane surfactant to the coating material, but vinyl chloride resin containing this substance has been proposed. Although the film has a haze-preventing effect, it tends to have low high-frequency adhesion, and also has problems in that it not only has low drip-proof properties at high temperatures but also tends to whiten due to water absorption. The present inventors focused on the fact that the degree of mist that occurs in a greenhouse differs depending on the type of drip-proofing agent added to the agricultural polyvinyl chloride film that covers the greenhouse. We researched ways to reduce the occurrence of haze.

As a result, by combining a nonionic surfactant with a relatively small amount of fluorine surfactant and adding it to agricultural polyvinyl chloride film, it maintains excellent drip-proof properties and a remarkable haze reduction effect. At the same time, since fluorine-based surfactants are effective even when added in small amounts, it is possible to obtain a covering material for greenhouse horticulture that does not impair properties such as high-frequency adhesion, transparency, water absorption whitening property, heat resistance, and slip property. I discovered that. However, since the addition of fluorosurfactants has a negative effect on weather resistance,
As a result of researching fluorosurfactants that have a good anti-haze effect when used in as small a quantity as possible, we found that by using a nonionic fluorosurfactant that is insoluble in phthalate ester plasticizers, we can reduce haze in small amounts. The present invention was completed based on the discovery that the preventive effect and its durability are good.

That is, the covering material for greenhouse horticulture of the present invention contains 30 parts of phthalate plasticizer per 10 parts of vinyl chloride resin.
~605 and at least 0.5 part by weight of . a nonionic surfactant, 0.01 to 1. It contains a nonionic fluorine surfactant that is insoluble in the phthalate plasticizer in the weighing part.

Vinyl chloride resins that can be used in the present invention include polyvinyl chloride and copolymers of vinyl chloride and other monomers, such as -nytylene, vinyl acetate, vinyl ether, maleic ester, and the like. It also includes blends of polyvinyl chloride and other polymers. If necessary, add lubricants, stabilizers, etc. commonly used for vinyl chloride resins.
It can contain ultraviolet absorbers, antioxidants, pigments, inorganic substances, antistatic agents, and the like. As the phthalate ester plasticizer that can be used in the present invention, general phthalate ester compounds such as di-2-ethylhexyl phthalate, di-n-octyl phthalate, dibutyl phthalate, diisodecyl phthalate, and butylbenzyl phthalate can be used. Di-2-ethylhexyl phthalate is preferred from the viewpoints of cost and price.

Further, there is no problem in using other plasticizers in combination, such as fatty acid ester plasticizers for improving cold resistance and phosphate ester plasticizers for improving weather resistance. The amount of phthalate plasticizer added is 3 parts by weight per 100 parts by weight of vinyl chloride resin.
0 to 6 parts by volume is preferred; if it is less than 3 parts by volume, the film becomes too hard; if it is more than 6 parts by volume, it becomes too soft; in either case, it is not suitable as a covering material for greenhouse horticulture. Nonionic surfactants used in the present invention include (4) ether type surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene polyoxypropylene ether, and (B) polyoxy Ethylene alkyl esters, ester-type products such as partially esterified products of polyhydric alcohols and fatty acids, (C) aminoether-type products such as polyoxyethylene alkylamine, (D) polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol Examples include ether ester types such as fatty acid ester, polyoxyethylene mannitan fatty acid ester, polyoxyethylene glyceryl fatty acid ester, and polyoxyethylene propylene glycol monofatty acid ester.

These nonionic surfactants can basically be selected arbitrarily, but preferably they have properties such as moldability, heat resistance, transparency, etc. in addition to maintaining drip-proof properties, It is desirable that the performance as an agricultural covering material is fully satisfied. Examples of suitable nonionic surfactants for obtaining the above performance include (1) a polyhydric alcohol such as sorbitan, sorbitol, mannitan, manninol, glycerin, diglycerin, and a fatty acid moiety having 12 to 22 carbon atoms; Ester (2) A polyoxyalkylene polyhydric alcohol in which the number of moles of ethylene oxide or propylene oxide added is 1 to 2, the polyhydric alcohol is sorbitan, sorbitol, mannitan, glycerin, or diglycerin, and the fatty acid has 12 to 22 carbon atoms. Fatty acid ester (3) (
Examples include mixtures of 1) and (2).

These nonionic surfactants are vinyl chloride resin 10
At least 0.5 parts by weight, preferably 1 part by weight
．． 0-5. Add within the voluminous volume range.

If the amount added is less than 0.5 parts by weight, a sufficient drip-proof effect cannot be obtained, and if it is more than 5.0 parts by weight, there will be a lot of bleeding, whitening will occur due to water absorption, and transparency will deteriorate, which is not preferable. As the fluorosurfactant, a nonionic fluorosurfactant that is insoluble in the phthalate plasticizer is used. Examples of the nonionic fluorine surfactant include Zonyl FBN (manufactured by DuPont), ? -001 (manufactured by Taikin Co., Ltd.), Surflon S-381 (manufactured by Asahi Glass Co., Ltd.), and the like. Whether a nonionic fluorosurfactant is insoluble in a phthalate plasticizer can be easily determined by mixing and stirring 100 parts by weight of a phthalate plasticizer and 1 part by weight of a nonionic fluorosurfactant. I can judge. The amount of the nonionic fluorosurfactant insoluble in the phthalate plasticizer is 0.01 to 1.0% per 100 parts by weight of the vinyl chloride resin. It is desirable to add 1 part by weight, preferably 0.05 to 0.5 part by weight.

If it is less than 0.01 part by weight, no effect will be observed, and if it is added in excess of 1.0 part by weight, discoloration will occur due to heating, which is not preferable.

Nonionic fluorosurfactants that are insoluble in phthalate ester plasticizers exhibit anti-haze effects in small amounts compared to soluble ones, and also have a longer lasting anti-haze effect. If the nonionic fluorosurfactant is soluble in the plasticizer, it will be difficult for the nonionic fluorosurfactant to appear on the film surface, and we believe that it will not be effective unless the amount is increased. Since nonionic fluorosurfactants reduce the weather resistance of polyvinyl chloride, it is preferable to add as little amount of nonionic fluorosurfactants as possible. Nonionic fluorosurfactants are preferred.

The polyvinyl chloride film of the present invention can be manufactured into a desired shape by calendering, extrusion, or the like.
If necessary, it may be used by laminating it on other synthetic resin films or sheets. The agricultural film of the present invention is insoluble in 0.5 parts by weight or more of a nonionic surfactant and 0.01 to 1.0 parts by weight of a phthalate plasticizer per 10 parts by weight of vinyl chloride resin. Since it is added in combination with a nonionic fluorine surfactant, the occurrence of haze can be significantly reduced, and the haze prevention effect is also long-lasting. Next, examples of the present invention are listed, but the present invention is not limited to these examples.

Examples 1 to 5, Comparative Examples 1 to 8 For 100 parts by weight of vinyl chloride resin (degree of polymerization 1300), 45 parts by weight of dioctyl phthalate, 3 parts by weight of tricresyl phosphate, 1.5 parts by weight of epoxidized resin, Ba
- The basic formulation is one containing 1 part by weight of Zn metal soap, 1 part by weight of Ba-Zn liquid stabilizer, and 0.1 part by weight of methylene bisamide.

Mix the surfactant in the amount shown in the table (parts by weight per 10 parts of vinyl chloride resin) with respect to the basic formulation, and
1. /Nl. These films were formed into thick films, and a comparative test was conducted on the generation of haze between these films.

The results are shown in the table. The tests and measurements were conducted using the following method.

[Comparative test of mist generation] Frontage 1.2rrL1 Height 1.0
The films obtained in the Examples and Comparative Examples were spread separately in a semi-cylindrical greenhouse with a depth of 8.0 rrL.

In the morning and evening, when haze was observed in the greenhouse, the degree of haze occurring in each greenhouse was evaluated with the naked eye.

Judgment was made after one week had elapsed after spreading, and observations were made twice on the 1st, in the morning and in the evening, to observe the occurrence of haze for 6 months.

The film with the least amount of haze was rated A, and the films with more haze were rated B, C, and D. [Weather resistance] Films were applied to 45 slopes of agricultural greenhouses, and weather resistance was observed for one year.

O: No change; Δ: Slight yellowing.

As is clear from the table, Examples 1 to 5, in which nonionic surfactants insoluble in phthalate ester plasticizers were used as fluorosurfactants, had a fluorine surface soluble in phthalate ester plasticizers. Example 4 using activator
Compared to No. 8, it can be seen that the anti-haze effect is remarkable even when a small amount of fluorosurfactant is used, and the sustainability of the anti-haze effect is good, and the weather resistance is also excellent.

Claims (1)

[Claims] 1. Per 100 parts by weight of vinyl chloride resin, 30 to 60 parts by weight of phthalic acid plasticizer, at least 0.5 part by weight of nonionic drip-proofing agent, and 0.01 to 1.0 parts by weight of phthalate ester. A covering material for greenhouse horticulture characterized by containing a nonionic fluorine surfactant that is insoluble in a plasticizer.