JPS6239620B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an agricultural vinyl chloride resin film, and more particularly to an agricultural vinyl chloride resin film that has high heat retention and excellent weather resistance. In recent years, farmers cultivating useful plants have widely adopted methods of promoting or suppressing cultivation using greenhouses or tunnels for the purpose of improving profitability. As materials for covering such houses or tunnels, polyethylene films, ethylene-vinyl acetate copolymer films, vinyl chloride resin films, polyethylene terephthalate films, polycarbonate films, etc. are used. Among them, vinyl chloride resin film is superior to other synthetic resin films in terms of weather resistance, transparency, heat retention, strength, and cost.
It is used the most. In order for agricultural synthetic resin films to exhibit excellent heat retention properties, (a) sunlight must be able to pass through the greenhouse or tunnel as much as possible during the day when sunlight is irradiating the film. (b) warmed by the sun's rays;
Avoid releasing the heat accumulated in the clay pot as much as possible. It is necessary to have two properties: A film made of vinyl chloride resin has better heat retention than a polyethylene film or an ethylene-vinyl acetate copolymer film. This is because the vinyl chloride resin film is highly transparent, so the sunlight reaches the inside of the house or tunnel and warms the clay.The heated clay warms the air, and the air flows inside the house or tunnel. This is thought to be due to natural convection, which warms the entire air inside the house or tunnel, and also because vinyl chloride resin has a high absorption rate for light rays with wavelengths in the infrared region of 3 to 40 microns. Figure 1 shows the infrared spectra of currently commercially available agricultural synthetic resin films and the radiant energy distribution of a 15°C black body. In Figure 1, curve 1 is an infrared spectrum line of agricultural polyvinyl chloride film, curve 2 is an agricultural polyethylene film, curve 3 is an infrared spectrum line of agricultural ethylene-vinyl acetate copolymer film, and curve 4 is an infrared spectrum line at 15°C. Shows the radiant energy distribution of a black body (corresponding to the radiant energy distribution from the ground inside a house or tunnel). From Figure 1, agricultural polyvinyl chloride film has a deeper absorption of light in the infrared wavelength range than the other two types of film, and in particular, the wavelength of radiation energy from the ground reaches its maximum at around 10 microns. It can be seen that it exhibits particularly deep absorption in the wavelength range of .
It is thought that absorption in this wavelength region is related to the heat retention properties of the film. By the way, in order to find out how much radiant energy from the ground is transmitted through a covering material such as a house or tunnel, the product of the transmittance of the film itself and the radiant energy from the ground is calculated for each wavelength in the infrared region. , it is sufficient to integrate over the target wavelength range. When the transmitted energy is calculated for the above three types of commercially available agricultural films (all with a thickness of 0.05 mm), the values shown in Table 1 are obtained.

[Table] Table 1 shows that polyvinyl chloride film has significantly lower transmitted energy than polyethylene film and ethylene-vinyl acetate copolymer film. Furthermore, in the case of polyvinyl chloride film, the transmission energy in the wavelength range of 3 to 16 microns is almost the same as that in the wavelength range of 16 to 40 microns, so the heat retention of this film is It turns out that in order to further improve the transmission energy, it is better to reduce the transmitted energy in both wavelength regions at the same time. In this way, as a method to reduce the transmitted energy in a specific wavelength range, the
Publication No. 9260, Japanese Patent Publication No. 47-13863, Japanese Patent Application Publication No. 1983
A technique described in Publication No. -43115 has been proposed. In both of these methods, inert solid fine particles having an ability to absorb in the infrared region are added to a synthetic resin as a base material to form a film. however,
It has been found that these conventional techniques have the following problems. (1) If silicon oxide, magnesium silicate, etc. that absorb in the infrared region are blended into a synthetic resin raw material and made into a film, and this film is used as a coating material, the temperature will increase approximately 2 to 3 months after the start of coating. This causes discoloration and eventually tears, making it unsuitable for long-term use. (2) Even if commonly used ultraviolet absorbers, light stabilizers, etc. are added for the purpose of improving this weather resistance, the decline in weather resistance of the film caused by the addition of inert solid particles cannot be suppressed. However, it is difficult to maintain weather resistance at a certain level over long periods of time. (3) The decrease in weather resistance of the film is proportional to the amount of inert solid fine particles added, and the relationship is such that the more the heat retention property of the film is improved, the lower the weather resistance is. Under such circumstances, the present inventors have conducted intensive studies to provide an agricultural vinyl chloride resin film that has high heat retention and excellent weather resistance, and as a result, they have completed the present invention. It is something. However, the gist of the present invention is to add (A) to a vinyl chloride resin composition containing a plasticizer.
(B) one or more types of inert solid fine particles that absorb in the infrared region of wavelengths 3 to 16 microns;
one or more types of inert solid fine particles that absorb in the infrared region of ~40 microns; (C) a metal phosphate salt that absorbs in the infrared wavelength region of 3 to 40 microns;
The present invention relates to an agricultural vinyl chloride resin film having excellent heat retention properties, which is formed by blending at least one kind of phosphite metal salts into a film. The present invention will be explained in detail below. In the present invention, vinyl chloride resin refers to polyvinyl chloride, a copolymer containing vinyl chloride as a main component and a monomer copolymerizable with it, and a copolymer containing polyvinyl chloride as a main component and copolymerizable with it, and This term includes blends with polymers and copolymers. The film according to the present invention is formed from a soft blended vinyl chloride resin composition.
To make a soft compound, use the above vinyl chloride resin 100
30 to 60 parts by weight of plasticizer is blended with respect to parts by weight. Preferred plasticizers in the present invention include, for example, di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, didodecyl phthalate,
Phthalic acid derivatives such as diundecyl phthalate; Isophthalic acid derivatives such as diisooctyl phthalate; Adipic acid derivatives such as di-n-butyl adipate and dioctyl adipate; Maleic acid derivatives such as di-n-butyl maleate; tri-n-butyl Citric acid derivatives such as citrate; Itaconic acid derivatives such as monobutyl itaconate; Oleic acid derivatives such as butyl oleate; Ricinoleic acid derivatives such as glycerin monoricinolate; Other tricresyl phosphate, epoxidized soybean oil, epoxy resin Examples include plasticizers and the like. The film according to the present invention contains (A) one or more kinds of inert solid particles that absorb in the infrared region of wavelengths from 3 to 16 microns, and (B) absorbing in the infrared region of wavelengths from 16 to 40 microns. One or more types of inert solid fine particles and (C) at least one of metal phosphates and metal phosphites that absorb in the infrared region of wavelengths from 3 to 40 microns are blended and mixed, respectively. There is. The inert solid fine particles of component (A) that absorb in the infrared region of wavelengths of 3 to 16 microns function to reduce the transmitted energy of the film of the present invention of light rays in the infrared region of wavelengths of 3 to 16 microns. be. Preferably used as component (A) are magnesium carbonate, magnesium silicate, silicon oxide, aluminum oxide, barium sulfate, calcium sulfate, and the like. These may be used alone or in combination of two or more. Among the examples, magnesium carbonate, magnesium silicate and silicon oxide are particularly preferred. If the amount of the above component (A) is too small, no improvement in heat retention can be expected; on the other hand, if it is too large, it will not only be impossible to maintain the weather resistance of the film at a desirable level, but also affect the mechanical properties of the film. This is not preferable because it also reduces the transparency of the film. A suitable range for blending is a total of 1 to 15 parts by weight of component (A) and component (B) described below, based on 100 parts by weight of the vinyl chloride resin. The inert solid fine particles of component (B) that absorb in the infrared region of wavelengths of 16 to 40 microns function to reduce the transmitted energy of light rays in the infrared region of wavelengths of 16 to 40 microns of the film according to the present invention. be. Those that can be used as component (B) include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, etc., and these may be used alone or in combination of two or more. If the amount of the above component (B) is too small, no improvement in heat retention can be expected; on the other hand, if it is too large,
This is not preferred because it not only fails to maintain the weather resistance of the film at a desirable level, but also deteriorates the mechanical properties, transparency, etc. of the film. The preferred blending amount range is 100 parts by weight of vinyl chloride resin, the sum of component (B) and component (A) above.
~15 parts by weight. (C) The metal phosphates and metal phosphites that absorb in the infrared wavelength range of 3 to 40 microns are listed above.
It functions to improve the weather resistance of the film containing component (A) and component (B), and to reduce the transmitted energy of light in the wavelength range of 3 to 40 microns. The (C) component has the general formula M〓H ₂ PO ₃ ,
M ₂ 〓HPO ₃ , M 〓H ₂ PO ₄ , M ₂ 〓HPO ₄ , M〓
It is a compound represented by HPO ₄ , M〓(H ₂ PO ₄ ) ₂ (in the formula, M means a metal component, and means monovalent and divalent), where M is a component of barium, Calcium, zinc, lead, aluminum, nickel, etc. are suitable. These (C) components may be used alone or in combination of two or more. If the amount of the above component (C) is too small, the weather resistance of the film cannot be improved to a desirable level, so it is undesirable. On the other hand, if it is too large, there will be a lot of gushing from the film, resulting in a decrease in transparency. This is not preferable as it also increases the adhesion of dust.
The preferred range of blending amount is 0.01 to 1 based on the total weight of components (A) and (B) [(C)/(A)+(B)=0.01 to 1] be within the range. ]. The above-mentioned components (A) to (C) are blended into the film according to the present invention, and in addition, lubricants, heat stabilizers, antistatic agents, antifogging agents, ultraviolet absorbers, pigments, and dyes may be added as necessary. Various resin additives such as these can be blended. Examples of lubricants or heat stabilizers that can be incorporated into the film of the present invention include polyethylene wax, liquid paraffin, stearic acid, zinc stearate, fatty alcohol, calcium stearate, barium stearate, barium ricinoleate, and dibutyl tin laurel. and dibutyltin malate. As the antistatic agent or antifogging agent that can be blended, nonionic surfactants are preferred, and specifically sorbitan surfactants such as sorbitan monostearate, sorbitan monopalmitate, and sorbitan monobenzoate; glycerin Glycerin surfactants such as monolaurate, diglycerin monopalmitate, and glycerin monostearate; polyethylene glycol surfactants such as polyethylene glycol monostearate and polyethylene glycol monopalmitate; alkylene oxide adducts of alkyl phenols;
Examples include esters of sorbitan/glycerin condensates and organic acids. Examples of the ultraviolet absorber include phenyl salicylate-based, cyanoacrylate-based, benzoate-based, benzophenone-based, and benzotriazole-based ultraviolet absorbers. Examples of pigments and dyes include titanium oxide, silica, ultramarine blue, and phthalocyanine blue. These various resin additives can be selected in the usual amount, for example, within the range of 5 parts by weight or less per 100 parts by weight of the vinyl chloride resin. Component (A) or
Component (C) and, if necessary, various resin additives are compounded and mixed using ordinary compounding techniques and mixing techniques, such as a ribbon blender, Banbury mixer, super mixer, and other compounding machines and mixers. This can be done by making it into a film afterwards. In order to form a film from the vinyl chloride resin composition, methods known per se, such as melt extrusion, solution casting, and calendering, may be employed. The film may be transparent or may have many small irregularities (embossed) on its surface. If the thickness of the film according to the present invention is too thin, the strength will be insufficient, which is undesirable.On the other hand, if the film is too thick, it will not be suitable for film processing, subsequent handling (cutting the film and joining it into a house shape, etc.) (including the work of expanding) etc.,
The range is preferably 0.03 to 0.2 mm. The film according to the present invention has the following effects and has extremely great agricultural utility value. Since the film according to the present invention contains inert solid fine particles that absorb heat rays, it prevents the infrared rays (heat rays) emitted from the soil in the wavelength range of 3 to 40 microns from being emitted outside the house or tunnel. It has excellent heat retention. As inert solid fine particles that absorb heat rays are used in combination with components (A) and (B) that have different absorption wavelength ranges, it is possible to reduce the transmitted energy over the entire range of infrared light with a wavelength of 3 to 40 microns. can. The amount of inert solid fine particles to be blended can be smaller than in the conventional case where a single compound is used alone. Since the film according to the present invention contains component (C) in addition to components (A) and (B), it is significantly more effective than conventional films that contain only inert solid particles that absorb heat rays. Shows excellent weather resistance. Hereinafter, the present invention will be explained in detail based on examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Examples 1 to 4, Comparative Examples 1 to 9 Polyvinyl chloride (=1400) 100 parts by weight Dictyl phthalate 50 Tricresyl phosphate 5 Epoxy resin (trade name "EP-828") 1 Barium-zinc Liquid stabilizer 1.5 〃 Barium stearate 0.2 〃 Zinc stearate 0.4 〃 Sorbitan monopalmitate 1.5 〃 The basic composition is the following, and the types and amounts of components (A), (B) and Component (C) was blended and stirred and mixed using a super mixer for 10 minutes. Each mixture was supplied to a calender heated to 165°C and formed into films by a conventional method to create 13 types of films with a thickness of 0.05 mm. The above 13 types of films were evaluated for weather resistance, heat retention, and blowout properties using the following methods. The evaluation results are shown in Table 2. (1) Weather resistance In Nagoya City, Aichi Prefecture, the test film was stretched outdoors on a stand facing south and inclined at 45 degrees to the ground (May 1980) and exposed to sunlight. The change in appearance of each film was visually observed and evaluated. The evaluation results of "weather resistance" each have the following significance. 〇……No change〇×………Slight brown spots are observed △………Brown spots are observed △×………Many brown spots are observed×……Browning over the entire surface (2) Heat retention We constructed 13 open-air tunnel frames, each 2m wide and 2m long, in a field in Kazushi District, Mie, and covered each tunnel with a film to maintain the temperature inside the tunnel at night. What was measured.
The temperature measurement period is from March 1st to March 10th, 1981.
10 days until today. The temperature is measured every hour from 6:00 pm to 6:00 am the next day, and the temperature during this period is averaged to be the average value for the day.
The average value for 10 days is shown as the average value. (3) Blowout property For each film left indoors for 6 months,
The film surface was lightly touched with a fingertip, and the judgment was made based on the marks left by the fingertip on the film surface. The evaluation criteria were as follows. 〇……There are almost no finger marks on the surface. △……Some finger marks are observed. ×……Things that leave significant finger marks.

【table】

[Table] From the following two tables, the following becomes clear. The film according to the present invention, which contains the three components (A) to (C), not only has excellent weather resistance, but also excellent heat retention, and there is extremely little spewing of additives onto the film surface. . Even if the film contains three components, if the amounts of the three components are not balanced (Comparative Example 1, Comparative Example 6, and Comparative Example 7), the film will not have excellent weather resistance and heat retention. However, films containing only one component (Comparative Examples 3 and 10) and films containing two components (Comparative Example 2) do not have excellent weather resistance and heat retention.

[Brief explanation of the drawing]

Figure 1 shows the infrared spectroscopy spectrum of agricultural synthetic resin film with a thickness of 0.05 mm currently on the market, and the 15
℃ shows the radiant energy distribution of a blackbody. In the figure, 1 is an infrared spectrum curve of agricultural polyvinyl chloride film, 2 is an infrared spectrum curve of agricultural polyethylene film, 3 is an agricultural ethylene-vinyl acetate copolymer film spectrum curve, and 4 is a 15°C Each shows the radiant energy distribution of a black body.

Claims (1)

[Scope of Claims] 1. A vinyl chloride resin composition containing a plasticizer, (A) inert solid fine particles having absorption in the infrared region of wavelengths 3 to 16 microns, and (B) wavelengths of 16 to 40 microns. The total amount of components (A) and (B) is 1 to 15 parts by weight per 100 parts by weight of vinyl chloride resin, and (C) the wavelength is 3 to 40 microns. Metal phosphates or metal phosphites that absorb in the infrared region of An agricultural vinyl chloride resin film characterized by: 2. It is characterized by containing at least one of magnesium carbonate, magnesium silicate, and silicon oxide as component (A), and at least one of magnesium hydroxide and aluminum hydroxide as component (B). An agricultural vinyl chloride resin film according to claim 1. 3 The metal components of the metal phosphate and metal phosphite as component (C) are calcium, barium,
The agricultural vinyl chloride resin film according to claim 1, characterized in that the film is selected from zinc, lead, or aluminum.