JP2814258B2 - Agricultural PVC resin film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin film for agriculture, and more particularly, to a vinyl chloride resin film for agriculture having excellent transparency, heat retention and dust resistance.

[Conventional technology]

In recent years, farmers growing crops have widely adopted the method of forcing cultivation of crops in a house (greenhouse) or a tunnel in order to increase profitability.

Insulation films of agricultural polyvinyl chloride resin used in house cultivation and tunnel cultivation of agricultural products are required to have not only transparency but also heat insulation. However, when used for a long time, dust accumulates, the film is deteriorated, and the transparency is lost, but it is known that it can be improved by applying acrylic (Japanese Patent Publication No. 62-38143). In order to prevent cooling at night, a filler such as hydrotalcite is blended (Japanese Patent Application Laid-Open No. 60-104141), and a silane-treated fine silicon oxide powder is also mixed (Japanese Patent Application Laid-Open No. 63-289053). Gazette) is known.

For the growth of crops, warming at night appears as a significant difference in crop yield and crop quality. Therefore, it is very important that the agricultural film has good heat insulation at night. Nighttime cooling in an agricultural house, tunnel, or the like is mainly caused by the fact that infrared rays emitted from an object having a temperature near room temperature, such as the ground, pass through the film and dissipate outside. In order to prevent such cooling, a specific filler is blended into the agricultural film to block transmission of infrared rays. However, conventional vinyl chloride resin heat-insulating films, by blending a filler to block the transmission of infrared light at night, although heat insulation can be imparted, the transparency is reduced, the sunshine is reduced during the day, It becomes difficult for the ground to rise. For this reason, it is desired that the transparency at the initial stage of expansion be 5% or less in cloudiness, but 10 to 30% in cloudiness.
Often it is. Even if the transparency at the initial stage of expansion is 5% or less in the haze value, the transparency gradually decreases over time due to the accumulation of dust and the deterioration of the film due to long-term use, and the haze value becomes 15% or more. That is, the temperature rise in the house due to daytime solar irradiation is impaired along with the decrease in transparency.

Accordingly, the present inventors have conducted intensive studies to solve these problems, and found that the average particle size of the primary particles was 0.5 to 12 parts by weight based on 100 parts by weight of polyvinyl chloride, a plasticizer and the polyvinyl chloride. Agriculture with excellent transparency, heat retention and dust resistance by applying an acrylic polymer coating on at least one surface of a film composed of a composition containing silicon oxide fine powder with a diameter of 200 nm or less and treated with silane. It was found that a vinyl chloride resin film was obtained, and the present invention was completed.

The coating agent of the present invention is composed of an acrylic polymer, which is an acrylic acid alkyl ester such as methyl acrylate, ethyl acrylate, butyl acrylate, or 2 ethylhexyl acrylate, and / or methyl methacrylate or ethyl methacrylate. Butyl methacrylate, 2-ethylhexyl methacrylate or other alkyl methacrylate polymer or copolymer or a mixture of these polymers, preferably ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate A polymer or copolymer comprising an alkyl acrylate and / or methyl acrylate or a mixture of these polymers, more preferably butyl methacrylate and ethyl acrylate Methacrylate, a copolymer mainly comprising methyl methacrylate. Examples of the monomer copolymerizable with the polymer or copolymer include α, β-unsaturated acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic anhydride, and fumaric acid, and esters thereof. Or hydroxyalkyl esters of α, β-unsaturated carboxylic acids such as 2-hydroxyethyl acrylate or methacrylate, 2-hydroxypropyl acrylate or methacrylate, vinyl compounds such as ethylene, propylene, α-olefin, acrylamide, Examples thereof include vinyl monomers such as n-methylol acrylamide and vinyl ether, and vinyl esters such as styrene, α-methylstyrene, vinyl toluene, vinyl propionate, and vinyl vasatate. The coating of the acrylic polymer may be a coating of an acrylic polymer blended with a vinyl chloride resin.

The coating amount of the acrylic polymer coating agent was 0.2 mm in thickness.
It is preferred to apply ~ 10μ. If the coating amount is less than 0.2 μm, uniform coating becomes difficult and the dustproof effect is reduced. If the coating amount is more than 10 μm, not only the cost increases but also gravure coating becomes difficult.

These acrylic polymer coating agents can be easily dissolved and applied with a solvent, and any solvent may be used as long as it dissolves the polymer. Generally, acetone, methyl ethyl ketone, getyl ketone, methyl isobutyl ketone, ethyl acetate, methyl acetate, propyl acetate, benzene, toluene, xylene, methanol, ethanol, propanol, isopropanol, tetrahydrofuran,
A single solvent or a mixture of solvents such as dimethyl acetoacid and methyl cellosolve is used. The concentration at which the polymer is dissolved in the solvent is not limited by the properties of each polymer, but it is preferably used at 10 to 30%.

The vinyl chloride resin film of the present invention is coated with a coating agent on at least one surface, and the coated surface is always installed outside the house or tunnel.

As the silicon oxide fine powder used in the present invention,
Selected from synthetic silicon oxide and natural silicon oxide. Examples of the synthetic silicon oxide include those produced in a gas phase process (dry process) and precipitated silicon oxide produced in a liquid phase process (wet process). Examples of the natural silicon oxide include fine powders such as quartz, quartz, agate, and silica sand. In the present invention, these silicon oxide fine powders whose primary particles have an average particle diameter of 200 nm or less are used. Preferably, the average particle diameter of the primary particles is 200 nm or less,
If it exceeds m, the transparency of the soft polyvinyl chloride becomes poor, which is not preferable.

As the silicon oxide fine powder of the present invention, silane-treated powder is used. The silane treatment method is to include a silane coupling agent and a silane compound obtained by subjecting a silicon oxide fine powder to a surface treatment. The surface treatment may be a simple treatment of a mixture of fine silicon oxide powder, a silane coupling agent, and a silane compound.Also, a hydrogen of a hydroxyl group bonded to silicon of a fine silicon oxide powder and an alkyl group capable of reacting with the hydrogen may be used. It may be one obtained by reacting with a contained silane compound. Examples of the silane compound include dimethylchlorosilane and trimethylchlorosilane. It is preferable that 35% or more of the hydrogen of the hydroxyl group bonded to silicon in the fine silicon oxide powder is substituted with an alkyl group-containing group. The amount of the silane-treated silicon oxide fine powder of the present invention is the same as that of the polyvinyl chloride.
0.5 to 12 parts by weight, preferably 3 to 7 parts by weight, is used per 100 parts by weight. If the amount is less than 0.5 parts by weight, the resulting film will have insufficient heat retention. On the other hand, when the amount exceeds 12 parts by weight, the transparency of the obtained film is deteriorated and the mechanical strength is lowered, which is not preferable.

The polyvinyl chloride used in the present invention is, in addition to a vinyl chloride homopolymer, a monomer mainly composed of vinyl chloride and copolymerizable therewith, such as vinyl acetate, vinyl stearate, vinyl caproate, vinylidene chloride, Copolymers with vinyl cetyl ether, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, maleic acid, maleic acid ester and the like, blends thereof, and other polymers and copolymers thereof It is meant to include a blend.

The plasticizer of the present invention is used for softening a polyvinyl chloride composition as an agricultural film. Examples of the plasticizer usable herein include phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, didodecyl phthalate, diundecyl phthalate, isophthalic acid derivatives and adipic acid Derivatives such as maleic acid, citric acid, itaconic acid, oleic acid and ricinoleic acid, as well as tricresyl, phosphate, epoxy soybean oil and epoxy resin. The amount of the plasticizer to be used is preferably 25 to 70 parts by weight of the plasticizer based on 100 parts by weight of the polyvinyl chloride.

The composition of the present invention comprises, in addition to polyvinyl chloride, a plasticizer and a specific silane-treated silicon oxide, infrared blocking agents such as silane-untreated silicon oxide, lubricants, heat stabilizers, slip agents, dustproofing agents, and ultraviolet rays. Absorbers, pigments and the like can be included in a range that does not impair the object of the present invention. These additives are preferably used in an amount of 5 parts by weight or less based on 100 parts by weight of the polyvinyl chloride.

The agricultural vinyl chloride resin film of the present invention is a transparent agricultural film having a low haze value and good transparency before being stretched. The daytime solar irradiation is increased, and the ground and the like are easily heated. Further, it is an agricultural film having a low haze value and not deteriorating the transparency even after long-term use without the addition of an ultraviolet absorber, and has excellent dust resistance and little deterioration of the film. For this reason, it is an agricultural film excellent in heat insulation, and the temperature can be raised by several degrees as compared with the conventional heat insulation film. Especially, the heat retention at night appeared as a remarkable difference between the yield and the quality of the crops, and could be widely used for various kinds of crops.

〔Example〕

Next, examples are shown, but the present invention is not limited to these examples.

Examples 1-4 Comparative Examples 1-5 Polyvinyl chloride (= 1300) 100 parts by weight Dioctyl phthalate 50 〃 Tricresyl phosphate 5 parts by weight Epoxy soybean oil 3 〃 Barium zinc composite stabilizer 1.5 〃 Sorbitan monopalmitate 1.5 〃 In a composition consisting of 0.5% of methylenebisstearic acid amide, 0.016 μm of silane-untreated silicon oxide fine powder, 0.016 μm of silane-treated silicon oxide fine powder (R-972 manufactured by Nippon Aerosil) in parts by weight shown in Table 1, 1.4μ silane treated silicon oxide powder was blended. Each composition was stirred and mixed with a spar mixer for 10 minutes, and a 0.075 mm-thick film was produced with a normal calender roll.

Next, a methyl methacrylate-based coating agent [Surface coating agent OCV R-001 manufactured by Osaka Organic Chemical Industry Co., Ltd.] was dissolved at 17% by weight in an ethyl acetate solvent, and one side of each film shown in Table 1 was dissolved. After coating with a gravure coater,
It was dried by passing through a hot air drying oven at 0 ° C. for 30 seconds, and the surface was covered with about 1.7 μm of a methyl methacrylate polymer. Table 1 shows the evaluation results of the films.

The evaluation and judgment methods of these qualities were as follows.

1) Insulation: The surface coated with the acrylic polymer coating agent of various films is housed outside (tunnel type, length
Measure the temperature day and night with an automatic thermometer.
The measurement was carried out in Kumamoto for five months from October 1987 to March of the following year.
From the 19th of the month to the 24th of October of the same year, it was the average of the measured values for 5 days. The measured value is obtained by reading the house temperature every hour during 24 hours as reading data. The average temperature of the house 5 months after the expansion in the table is the average value for 5 days from March 14, 1988 to March 19, 1988. The measured value was the same as the measured value immediately after stretching.

2) Transparency: Haze meter ｛Nippon Denshoku Co., Ltd.｝ ASTM
According to -D-1003.

Claims (1)

(57) [Claims] 1. A silane-treated silicon oxide fine powder having an average primary particle size of 200 nm or less, comprising 0.5 to 12 parts by weight of polyvinyl chloride, a plasticizer and 100 parts by weight of the polyvinyl chloride. An agricultural vinyl chloride resin film in which an acrylic polymer coating material is applied to at least one surface of a film made of the composition.