JPS6249906B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a synthetic resin film, and more specifically, it is made of a synthetic resin containing a specific fluorine-containing surfactant, reduces the occurrence of haze in an enclosed space, and has an excellent long-lasting effect. The present invention relates to synthetic resin films, particularly agricultural synthetic resin films. In recent years, greenhouse cultivation has enabled a stable supply of various vegetables and fruit trees throughout the year. Synthetic resin films such as polyvinyl chloride and polyethylene are widely used as covering materials for greenhouses. 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 this heat retention, improve the airtightness of the greenhouse,
It is necessary to suppress the amount of heat escaping through draft ventilation. Recently, with the trend toward energy conservation in particular, management techniques have been implemented to increase the airtightness of greenhouses as much as possible in order to effectively utilize solar energy without adversely affecting the crops in the greenhouse. ing. 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 generated inside the greenhouse increases significantly. Moya is said to be closely related to the pests and diseases of cultivated crops and the quality of the harvest, 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, since the heat retention of greenhouses is generally important, ventilation is often not possible, which has been a major problem in greenhouse cultivation. Since the occurrence of haze is essentially a phenomenon caused by moisture in the greenhouse, the occurrence of haze 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 soil surface in 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. As another method for preventing haze, that is, a method for reducing the occurrence of haze by improving coating materials, JP-A-55-91663 and JP-A-57-12070 disclose the addition of a silicone surfactant. A method is disclosed. However, although synthetic resin films containing these substances have an anti-haze effect, they have poor adhesion between the films, which is a necessary characteristic of coating materials, and furthermore, their drip-proof properties are severely degraded.
The drawback was that the sustainability of the haze prevention effect was poor. JP-A No. 57-14648 discloses a method of adding a fluorine-based surfactant, but conventional fluorine-based surfactants have little haze prevention effect when added in small amounts. The problem is that the anti-haze effect is not long-lasting, and when added in large amounts, the adhesion between films and the weather resistance are significantly reduced. The present inventors have developed a coating that has an excellent anti-haze effect and its sustainability, and does not adversely affect other properties of the coating material, such as adhesion between films, weather resistance, drip resistance, transparency, and slip resistance. The present invention was completed as a result of intensive research into materials. Synthetic resin film materials that can be used in the present invention include ordinary synthetic resins, such as polyvinyl chloride, polyolefin, acrylic resin, polyester, and polyamide, which have film-forming properties, or blends of such synthetic resins. Among these, polyvinyl chloride and polyethylene resins are particularly preferred from the viewpoint of weather resistance, economical efficiency, and light transmittance. type resins are most preferred. As the polyvinyl chloride resin, a vinyl chloride homopolymer and a copolymer with vinyl acetate, ethylene, propylene, alkyl vinyl ether, etc. can be used. As other additives added to the synthetic resin, commonly used plasticizers, stabilizers, lubricants, fillers, ultraviolet absorbers, antistatic agents, antioxidants, etc. can be used. There are no restrictions. The fluorine-containing surfactant used in the present invention has the general formula [In the formula, Rf is a C ₃ to _{C 21} fluorine-containing aliphatic group, R
is [(CH ₂ ) ₂ O] _o R′ or

[Formula], R' is a C _1-3 alkyl group, R'' is a C _5-10 alkyl group, and n is 5-15.] In the above general formula, fluorine-containing fat The group group may be either saturated or unsaturated, and may be linear or branched.Specific examples of these fluorine-containing surfactants include: The amount of fluorine-containing surfactant (1) added is based on 100 parts by weight of the synthetic resin when used in combination with the drip-proof agent below.
0.01 to 0.2 parts by weight is preferred. If it is less than 0.01 part by weight, the anti-haze effect will be small, while if it is added in excess of 0.2 part by weight, no improvement will be seen in the anti-haze effect or its sustainability, but rather the weather resistance will tend to deteriorate. On the other hand, conventionally used fluorine-containing surfactants include C ₈ F ₁₇ COONH ₄ , C ₈ F ₁₇ SO ₃ K,

Anionic surfactants such as [Formula], C ₈ F ₁₇ SO ₂ NHC ₃ H ₆ N(CH ₃ ) ₃ I, Cationic surfactants such as C ₈ F ₁₇ CH ₂ CH ₂ N (CH ₃ ) ₃ Cl, C ₈ F ₁₇ SO ₂ N (C ₃ H ₇ ) C ₂ H ₄ O (C ₂ H ₄ O)
nH _{, C9F19CH2CH2O ( C2H4O} ) _{nH ,}

There are nonionic surfactants such as [Formula], but in contrast to the case of the fluorinated surfactant (1) used in the present invention, these conventional fluorinated surfactants are 0.2 parts by weight. If the above amount is not added, a satisfactory anti-haze effect cannot be obtained, and its sustainability is also poor. Furthermore, the adhesion between the films and the weather resistance are also poor. However, the fluorine-containing surfactant used in the present invention
(1) has superior drip-proofing and haze-preventing effects even when used in small amounts, and is effective even without using a drip-proofing agent, compared to the above-mentioned conventional products. In the present invention, the drip-proofing agent preferably used together with the fluorine-containing surfactant may be any surfactant capable of imparting drip-proofing properties to the synthetic resin film, and is usually a non-ionic surfactant. Active agents are preferably used. Specific examples of these include (A) ether types such as polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, and polyoxyethylene polyoxypropylene ether; (B) polyoxyethylene alkyl ester and polyhydric alcohols; Ester-type products such as partially esterified fatty acids, (C) Aminoether-type products such as polyoxyethylene alkylamine, (D) Polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene mannitan Examples include ether ester types such as 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 drip-proofing properties, and It is desirable that the performance as an agricultural covering material is fully satisfied. Examples of suitable nonionic surfactants for achieving the above performance include (i) polyhydric alcohols such as sorbitan, sorbitol, mannitan, mannitol, glycerin, diglycerin, and fatty acid moieties having 12 to 22 carbon atoms; Ester (ii) The number of moles of ethylene oxide or propylene oxide added is 1 to 20, the polyhydric alcohol is sorbitan, sorbitol, mannitan, glycerin, diglycerin, and the number of carbon atoms in the fatty acid is 12 to 20.
22, a mixture of polyoxyalkylene polyhydric alcohol and fatty acid ester (iii) (i) (ii). These drip-proofing agents are usually added in an amount of at least 0.5 parts by weight, preferably in the range of 1.0 to 5.0 parts by weight, per 100 parts by weight of the synthetic resin. 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 is a tendency for excessive bleeding, water absorption, whitening, and undesirable decrease in transparency. As described above, since the synthetic resin film of the present invention is made of a synthetic resin containing the above-mentioned fluorine-containing surfactant (1), preferably together with a drip-proofing agent, it has a remarkable anti-haze effect. Its durability is also excellent. Furthermore, the fluorine-containing surfactant (1) is
Since the desired effect can be achieved with the addition of a small amount, there is almost no adverse effect on the adhesion and weather resistance between films, and the synthetic resin film of the present invention has extremely high utility value as an agricultural coating material. Next, the present invention will be explained in more detail by showing Examples and Comparative Examples. The haze evaluation method, drip-proof evaluation method, weather resistance evaluation method, and film adhesion evaluation method in Examples and Comparative Examples are as follows. Moya evaluation method The films obtained in each example and each comparative example were spread separately in a tunnel-shaped greenhouse with a width of 1 m, a height of 0.9 m, and a depth of 10 m, and the occurrence of haze in the morning and evening was observed. Evaluated by: 〇: No haze at all □: Slight haze △: Slightly hazy ×: Very much haze Drip-proof evaluation method In the above tunnel-shaped greenhouse, the quality of drip-proofing was checked with the naked eye. The film was observed and evaluated using the following criteria: 〇: Very good drip-proofing property □: Good drip-proofing property △: Poor drip-proofing property ×: Very poor drip-proofing property Weather resistance evaluation method The film was exposed to a grid outdoors. The state of deterioration was observed with the naked eye and evaluated using the following criteria: 〇: No discoloration at all □: Slight discoloration △: Discoloration observed in about half of the area ×: Film adhesion with significant discoloration on the entire surface Evaluation method After producing the films, two films were left at room temperature for 6 months and then adhered using a high-frequency sewing machine, pulled until the film was cut, and the adhesive strength was evaluated according to the following criteria. ○: The adhesive part does not peel off at all, and the film is torn. △: Approximately half of the adhesive part is peeled off. ×: All of the adhesive parts are peeled off. Examples 1 to 8 and Comparative Examples 1 to 13 Basic composition Part by weight Vinyl chloride resin (degree of polymerization 1300) 100 Dioctyl phthalate 44 Tricresyl Phosphate 6 Epoxy resin 2 Ba-Zn stabilizer 2 Methylene bisstearamide 0.1 Ultraviolet absorber 0.1 In addition to the above basic formulation, fluorine-containing surfactant,
A nonionic surfactant and a silicone surfactant were blended singly or as a mixture in the proportions shown in Table 1 (parts by weight based on 100 parts by weight of vinyl chloride resin), and calender-molded into a film with a thickness of 0.1 mm. The obtained film was subjected to a haze test, a drip-proof test, a weather resistance test, and a film adhesion test, and evaluated according to the above-mentioned criteria. The results are shown in Table 2. As is clear from the results in Table 2, the film of the present invention has excellent anti-haze effect and durability;
It is an extremely useful synthetic resin film that has excellent weather resistance and film adhesion, especially as an agricultural film.

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Claims (1)

[Claims] 1. General formula [In the formula, Rf is a C ₃ to _{C 21} fluorine-containing aliphatic group, R
is [(CH ₂ ) ₂ O] _o R′ or [Formula], R′ is a C _1-3 alkyl group, R″ is a C _5-10 alkyl group, and n is 5-15.] A synthetic resin film comprising a fluorine-containing surfactant represented by: 2. The synthetic resin film according to claim 1, wherein the synthetic resin further contains a drip-proofing agent.