JPH0572942B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to synthetic resin covering materials for agriculture. More specifically, it has the ability to suppress fog generation near the inner surface of the coating material (this ability is called an antifogging agent), and the ability to exhibit excellent antifogging effects over a long period of time (this ability is called an antifogging agent). (referred to as anti-fog durability) relates to agricultural synthetic resin covering materials. [Prior Art] In recent years, in order to increase the productivity and marketability of useful plants, so-called house cultivation has been developed, in which useful plants are cultivated under forced, semi-forced or suppressed cultivation under agricultural covering materials such as agricultural vinyl film. and tunnel cultivation are widely practiced. In greenhouse cultivation and tunnel cultivation, most of the synthetic resin covering materials currently used, such as vinyl chloride resin films, cover the inner surface of the covering material (the surface facing the inside of the greenhouse or tunnel).
same as below. ) contains an antifogging agent (mainly sorbitan fatty acid ester; glycerin fatty acid ester, etc.), which is a type of surfactant, in order to promote the flow of water droplets and increase the amount of sunlight incident. When covered with a coating material containing such an antifogging agent, the temperature difference between the inside and outside of the coating material becomes large.
The phenomenon of fog generation near the inner surface of the coating is often observed. This fog phenomenon often occurs in late autumn or winter, which is the most important period for greenhouse cultivation, tunnel cultivation, and other facility cultivation. The exact cause of the fog phenomenon is not known, but the temperature inside the greenhouse or tunnel,
Humidity, the temperature of the soil inside the house or tunnel, the water content, the amount of solar radiation to the house or tunnel, the degree of hydrophilicity of the wet surface of the covering material, etc. all interact subtly, and the humidity inside the house or tunnel causes temperature changes. This is presumed to be due to the fact that the moisture adheres smoothly to the surface of the coating material and does not flow, causing some of the moisture to form a mist near the inner surface of the coating material. According to observations by the present inventors, it has been found that such a fog generation phenomenon occurs near the ground surface in a greenhouse or tunnel, near cultivated plants, and near the inner surface of the covering material. Furthermore, the cladding material and the inner surface of the cladding material are cooled by the drop in outside temperature, creating a temperature difference between them and the inside of the house, and the warm, humid air inside the house is moved near the inner surface of the cladding material due to natural convection. It has been found that when moving, water vapor that can no longer be contained in the air condenses into reduced water droplets, forms a mist, and spreads into the house or tunnel through natural convection. If the mist-like minute water droplets that are once generated evaporate and disappear again during natural convection, the fog will not spread into the house or tunnel, but if the rate of evaporation and disappearance is slow, the entire house or tunnel will disappear. It also turned out to be a thick fog. Such fog generation phenomenon wets the leaves, stems, flowers, fruits, etc. of useful crops grown in greenhouses or tunnels, causing the occurrence of diseases or even aiding the spread of diseases. Also, if the cultivated crops become wet, the heat necessary to dry them is required, which causes disadvantages such as the need for more fuel for heating the greenhouse or tunnel. Furthermore, since the visibility inside the greenhouse becomes poor, there are also disadvantages such as a decrease in the efficiency of agricultural work. In order to overcome these disadvantages, conventional methods have been to use colored synthetic agricultural resin films or cover the soil inside greenhouses or tunnels with mulching film in order to soften temperature changes inside greenhouses or tunnels. Reducing the amount of water evaporation by dripping water, or improving the irrigation time (for example, watering later in the evening, adjusting the area and amount of water to be irrigated, etc.), and improving the irrigation method and equipment. Such measures have been adopted. However, none of these methods was effective in completely suppressing the fog generation phenomenon. As a technology that improves these drawbacks,
As described in Japanese Patent No. 57-14648, a method has been proposed in which a surfactant as an antifogging agent and a fluorine-containing surfactant to improve antifogging properties are used in combination. According to experiments conducted by the present inventors, not all fluorine-based surfactants exhibit fog-proofing properties;
It has also been found that even compounds that exhibit fog-proofing properties may have an adverse effect on the anti-fogging durability of the film. [Problems sought to be solved by the invention] Under such circumstances, the present inventors have discovered that the coating material has the ability to suppress the fog generation phenomenon near the inner surface (fog-proof property) and has excellent anti-fog durability. The present invention has been completed as a result of intensive studies aimed at providing synthetic resin covering materials for agriculture. [Means for Solving the Problems] The gist of the present invention is that a fluorine-containing compound represented by the following general formula () and/or (), a polyhydric alcohol, and a carbon number
An agricultural synthesis characterized by containing an antifogging agent derived from 10 to 22 fatty acids, or an antifogging agent derived from a polyhydric alcohol, a fatty acid having 10 to 22 carbon atoms, and an alkylene oxide. Exists in resin coating materials. General formula:

[ka]

[In (), (), R _f is a polyfluoroalkyl group having 4 to 20 carbon atoms, R is H, and is a polyfluoroalkyl group having 1 to 20 carbon atoms.
10 alkyl groups or

[Formula] (R' is an alkyl group having 1 to 10 carbon atoms), n and m are integers of 1 to 20. ] However, in (), ()

[Formula] and (-CH ₂ CH ₂ O) _-n are bonded randomly or in a block shape. The present invention will be explained in detail below. The synthetic resin material constituting the agricultural synthetic resin coating material of the present invention generally includes film-forming thermoplastic synthetic resins. Specifically, monomers such as vinyl chloride, ethylene, propylene, acrylic esters, methacrylic esters, etc. alone or copolymers of these monomers, or at least one of these monomers and other copolymers are possible. Examples include copolymers with monomers (eg, vinyl acetate, vinylidene chloride, etc.), fluorine-containing resins, polyesters, polyamides, etc., and blends of these polymers. Among these, vinyl chloride resins (i.e. polyvinyl chloride and its copolymers containing 50% by weight of vinyl chloride) and ethylene resins (i.e. , polyethylene and its copolymers containing 50% or more by weight of ethylene) are preferred, most preferably polyvinyl chloride. In the present invention, the general formula () and /
Specific examples of the fluorine-containing compound represented by or () are as follows.

【table】

【table】 In the above

[Formula] (PO group) and CH ₂ CH ₂ O (EO group) are bonded in a block form or PO and EO groups are bonded randomly. The above specific examples of fluorine-containing compounds do not limit the present invention. The fluorine-containing compounds represented by the general formulas () and () can be used alone, and
Two or more types can also be used in combination. The amount of this fluorine-containing compound added to the synthetic resin coating material can be varied over a wide range depending on the type of fluorine-containing compound to be blended, the type of base synthetic resin, etc. Generally, 100 parts by weight of the base synthetic resin (however, plasticizers are not included in the calculation. The same applies hereinafter).
may be at least 0.01 part by weight;
In addition, although the upper limit of the blending amount is not strictly limited, if it is blended in too large a quantity, there is a risk of bleed-out or clouding, so it is usually 2.0.
Parts by weight or less are sufficient. The preferred range of blending amount is
The amount is 0.02 to 1.0 parts by weight per 100 parts by weight of the synthetic resin material. In order to impart antifogging properties to the agricultural coating material of the present invention, these synthetic resin base materials are blended with an antifogging agent that has been conventionally used in the field of agricultural vinyl chloride resin films. Therefore, the antifogging agent used in the present invention contains polyhydric alcohols and carbon atoms of 10 to 22 carbon atoms.
These are antifogging agents derived from fatty acids, or antifogging agents derived from polyhydric alcohols, fatty acids having 10 to 22 carbon atoms, and alkylene oxides. These are compounds that fall under the category of nonionic surfactants. Specific examples of antifogging agents that can be used include polyhydric alcohols such as sorbitol, mannitol, glycerin, polyglycerin, pentaerythritol, and trimethylolpropane, and non-fogging agents derived from fatty acids having 10 to 22 carbon atoms. Examples include ionic surfactants and nonionic surfactants derived from the above polyhydric alcohols, fatty acids, and alkylene oxides. number of carbons
The 10 to 22 fatty acids may be either straight chain or branched chain fatty acids. More specifically, lauric acid, myristic acid,
In addition to fatty acids such as palmitic acid, stearic acid, isostearic acid, behenic acid, and oleic acid,
Examples include beef tallow, rapeseed oil, corn oil, soybean oil, cottonseed oil, palm oil, sesame oil, linseed oil, fatty acids obtained from these hydrogenated oils, and mixed fatty acids thereof. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and phenylene oxide. In addition, addition of alkylene oxide is performed after adding alkylene oxide to polyhydric alcohol.
The fatty acid may be esterified, or the alkylene oxide may be added after esterifying the polyhydric alcohol and the fatty acid. Two or more types of alkylene oxides may be added. The antifogging agent should also be selected from among those that exhibit antifogging properties even in the low temperature period of winter, are difficult to ooze out from the coating material even during the high temperature periods described below, and maintain antifogging properties for a long period of time. Polyhydric alcohols such as sorbitol,
Mannitol, a polyglycerin with a degree of condensation of 2 to 10, a nonionic surfactant whose fatty acid is derived from a fatty acid with 16 to 18 carbon atoms, or the above polyhydric alcohol and fatty acid, and ethylene oxide or propene oxide. Examples include nonionic surfactants derived from and. Also, among nonionic surfactants, during the esterification reaction of polyhydric alcohols and fatty acids, the number of water molecules released by the intramolecular dehydration condensation reaction of polyhydric alcohols is smaller than the number of water molecules per molecule of polyhydric alcohol. 2 or less is good. Furthermore, it is preferable that the diester content in the ester mixture obtained by the reaction of polyhydric alcohol and fatty acid is 20 to 80% by weight of the total weight.
In addition, a nonionic surfactant in which the total added amount of ethylene oxide and/or propylene oxide is 5 mol or less per mol of polyhydric alcohol is most preferred. The blending amount of the base resin of the antifogging agent can be the same as that used for conventional agricultural synthetic resin films. Generally, the amount can be in the range of 1 to 5 parts by weight, preferably in the range of 1.5 to 3.5 parts by weight, per 100 parts by weight of the synthetic resin base material. The synthetic resin base material constituting the agricultural covering material according to the present invention may also contain various conventional resin additives, such as plasticizers, lubricants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigment dyes, as necessary. etc., in conventional amounts. For example, regarding the soft vinyl chloride resin suitable for the present invention, a plasticizer can be blended in an amount of about 30 to 70 parts by weight to 100 parts by weight of polyvinyl chloride having a degree of polymerization of about 1000 to 2000. . Suitable plasticizers that can be used include, for example, isophthalic acid derivatives of phthalic acid such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, dipendyl phthalate, diisodecyl phthalate, didodecyl phthalate, diundecyl phthalate; Isophthalic acid derivatives such as octyl phthalate;
Adipic acid derivatives such as di-n-butyl adipate and dioctyl adipate; maleic acid derivatives such as di-n-butyl maleate; citric acid derivatives such as tri-n-butyl citrate; itaconic acid derivatives such as monobutyl itaconate; butyl Oleic acid derivatives such as oleate; ricinoleic acid derivatives such as glycerin monocitrate; and others such as tricresyl phosphate, tricylyl phosphate, epoxidized soybean oil, and epoxy resin plasticizers. In addition, examples of lubricants or heat stabilizers that can be included in the synthetic resin base material include polyethylene wax,
Examples include bisamide, stearic acid, zinc stearate, barium stearate, calcium stearate, barium ricinoleate, and the like. Examples of the ultraviolet absorber include benzotriazole-based, benzoate-based, benzophenone-based, cyanoacrylate-based, and phenyl salicylate-based ultraviolet absorbers. Examples of pigments and dyes include titanium oxide, silica, ultramarine blue, and phthalocyanine blue. These resin additives may be contained in a small amount of 5 parts by weight or less per 100 parts by weight of the synthetic resin base material. In order to incorporate fluorine-containing compounds, antifogging agents, and various resin additives, if necessary, into the base synthetic resin, conventional compounding techniques and mixing techniques such as ribbon blender, Banbury mixer, super mixer, etc. are used. This can be done by mixing the mixture using a blender or mixer and then forming it into a film. In order to form a film from a synthetic resin, a method known per se, such as a melt extrusion method, a solution casting method, a calender method, etc., may be employed. The thickness of the agricultural synthetic resin covering material according to the present invention is
If it is too thin, the strength will be insufficient and undesirable.On the other hand, if it is too thick, it will be inconvenient during film production and subsequent handling (including cutting the film and joining it into a house shape, spreading it into a house, etc.). Therefore, it is best to set it in the range of 0.01 to 0.5 mm. As mentioned above, the agricultural synthetic resin covering material according to the present invention improves the anti-fogging property and anti-fog durability of the inside covered with the covering material, but also improves the dust-proofing property of the outside of the covering material. It is better to leave it there. In order to improve the dustproof property, it is preferable to form a dustproof coating based on a solvent paint, a water-soluble paint, an ultraviolet curable paint, or the like. The agricultural synthetic resin covering material according to the present invention can be applied to agricultural and horticultural facilities such as greenhouses and tunnels, and used for cultivating useful plants, in the same manner as conventional agricultural covering materials. [Effects of the Invention] The agricultural synthetic resin covering material according to the present invention has the following particularly remarkable effects, and its industrial utility value is extremely large. (1) In tunnels, greenhouses covered with the agricultural synthetic resin covering material according to the present invention effectively suppress the generation of fog near the inner surface of the covering material, as is clear from the Examples described later. Its suppressive effect is extremely strong, and even in late autumn and winter, when it has been said that fog frequently occurs, it can actually completely suppress the occurrence of fog, and it has a remarkable effect on preventing the occurrence and spread of diseases on useful plants. be. Therefore, unlike the conventional method, there is no need to pay close attention to irrigation, etc. (2) Since the agricultural synthetic resin according to the present invention contains a specific fluorine-containing compound and a surfactant, it not only has an effect of suppressing fog generation, but also has excellent antifogging properties and long lasting antifogging properties. It is useful for the facility cultivation of useful plants. "Examples" 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 6, Comparative Examples 1 to 9 Polyvinyl chloride (=1300) 100 parts by weight Dioctyl phthalate 50 Ba-Zn liquid stabilizer 2 Ba-Zn powder stabilizer 1 The basic composition is The antifogging agent and fluorine-containing compound shown in Table 1 were added to the mixture in the proportions shown in Table 1. The mixture was fed to a calender molding machine heated to 180℃ and formed into a film using a conventional method.
Fourteen types of 0.075 mm films (excluding Comparative Example 9) were created. Commercially available thicknesses for the above 14 types of films
A total of 15 types including 0.075 mm of antifogging agricultural polyvinyl chloride film (Comparative Example 9) that does not contain fluorine-containing compounds were tested for antifogging properties and moisture condensation on the inner surface of the film according to the method described below. was evaluated. The results are shown in Table 1. Evaluation of anti-fog properties A field with a width of 2 m and a ridge height of 2
A single-roof type house measuring 20 m in length and 20 m in depth was coated with the above 15 types of films (August 2, 1980), and the antifogging properties of each film were observed with the naked eye. The numerical values of "antifogging performance evaluation" shown in Table 1 have the following meanings. “1”: Water adheres in a thin film and no water droplets are observed. "2": Water is attached in a thin film, but slightly large water droplets are observed. "3": Water is attached in a thin film, but large water droplets are observed to be attached in some areas. "4"...A state in which fine water droplets are observed to be attached partially. "5": A state in which fine water droplets are observed on the entire inner surface of the film. Amount of water condensation on the inner surface of the film A rain gutter was installed on the shoulder of the same type of house as the one used for the evaluation test in (1) above, extending in the direction of the depth of the house, and the amount of water flowing down the inner surface of the film was measured. thing. Tests were conducted in November 1981 on 15 types of film.
The greenhouse was covered on the 10th, and the amount of water condensation was measured for 20 days from December 5th to December 24th of the same year, and was calculated as the amount of water flowing down per hour per 11 square meters of the inner surface of the film. The unit of this value is
g/ ^m2・hr.

【table】

【table】

【table】

[Table] (Strawberry cultivation test) In a field in Isshi District, Mie Prefecture, 1
Fertilize with 3.0 kg of compost and 150 g of limestone per square meter, and add 15 g of fish meal and 5 g of urea 15 days before making the ridge.
g, 40 g of molten phosphorus fertilizer and 5 g of potassium chloride were applied. Two pipe houses with a width of 4.8 m and a depth of 50 m were constructed in this field, and on October 24, 1981, half of the pipe house (section A) in the length direction was covered with the film of Example 4. The remaining half (section B) was coated with the film of Example 5, respectively. The pipe house in the other building was similarly covered with the film of Example 6 (section C) and the film of Comparative Example 8 (section D). At the boundary between Wards A and B, the film of Example 4 and the film of Example 5 are hung from the ceiling as a partition, and at the border between Wards C and D, the film of Example 6 and the comparative example are hung from the ceiling. No. 8 film was hung from the ceiling to serve as a partition. Four ridges each measuring 30 cm in height and 60 cm in width were provided in each pipe house, and each ridge was covered with black mulching film. On October 30, 1981, at 30 cm intervals,
Strawberry seedlings (variety name: Haru no Kaori) were planted. On the 10th and 70th days after planting, add 15 g of fishmeal, 7.5 g of urea, and 10 g of potassium chloride per square meter as additional fertilizer.
were fertilized respectively. After planting, while cultivating strawberries according to conventional methods,
The following items were investigated in each ward between January 9th and January 28th, 1981. The result is
Shown in Table 2. Amount of water condensed on the inside of the film A rain gutter was installed on the shoulder of the pipe house, extending in the direction of the depth of the house, to collect water flowing down the inside surface of the film, and measure the amount of water. Measurements were carried out for 20 days and calculated as the average amount of water flowing down per hour per square meter of the inner surface of the film. The unit is g/m ² ·hr. Condition of water droplet adhesion on plant surface Water droplets adhering to leaves, stems, and fruits of plants under cultivation were observed and evaluated with the naked eye. The numerical values in the column "Plant surface water droplet adhesion status" in Table 2 have the following meanings. "1": No adhesion of water droplets was observed. "2"...Slight adhesion of water droplets is observed. "3"...There are stains and water droplets adhering to the leaf tips. "4"...Water droplets are also observed on the fruit. Disease occurrence status Evaluated by visually observing plants during cultivation. The evaluation criteria were as follows. If any disease outbreak was observed before the above evaluation period, a 1000x solution of Topjin hydrating agent was sprayed on all plots. "1"...No outbreak of disease is observed. "2"...The above occurrence is slightly observed. Amount of moisture absorbed by paper placed on the ground A ring made of wire was placed 10 cm above the ground.
On top of that, paper (5A, 11cmφ) made by Toyo Paper Co., Ltd.
The amount of moisture absorbed by this paper was measured. The paper was placed on a wheel at 3:00 p.m., collected at 8:00 a.m. the next day, and the increase in weight of the paper was measured.The average value for 20 days was calculated. Evaluation of fog occurrence The degree of fog occurrence was determined by observing 12 times a day every hour from 7:00 a.m. to 6:00 p.m., and the results are shown numerically in Table 2 as "fog occurrence evaluation." . The numerical values of "fog generation evaluation" have the following meanings. "1": No fog is observed inside the house, or a slight amount of fog is generated only near the inner surface of the film. "2"...There is fog throughout the house, but 25
The back of the house m ahead can be clearly identified. "3"...A slightly thick fog appears throughout the house, 25
A state where it is not possible to clearly identify the back of the house m ahead. "4"...Dense fog has formed throughout the house, making it impossible to discern the back of the house from 25 meters away.

[Table] From Tables 1 and 2, the following becomes clear. (1) The agricultural synthetic resin coating material according to the present invention exhibits little deterioration in antifogging properties even when exposed to high temperatures in summer. (2) When the fluorine-containing compound is represented by the general formula () or (), the coating material has excellent antifogging properties and antifogging durability. On the contrary,
When the fluorine-containing compound is not represented by the general formula () or (), the antifogging durability of the film will not be excellent. (3) Moisture existing in the space of the house or tunnel formed by the agricultural synthetic resin coating material according to the present invention is promoted to condense on the inner surface of the coating. This can reduce the humidity in the space, reduce the adhesion of water droplets to the surface of the plants being cultivated, and reduce the occurrence of diseases.

Claims (1)

[Scope of Claims] 1. An antifogging agent derived from a fluorine-containing compound represented by the following general formula () and/or (), a polyhydric alcohol, and a fatty acid having 10 to 22 carbon atoms;
Alternatively, an agricultural synthetic resin coating material containing a polyhydric alcohol, a fatty acid having 10 to 22 carbon atoms, and an antifogging agent derived from alkylene oxide. General formula: [Chemical formula] [Chemical formula] [In (), (), R _f is a polyfluoroalkyl group having 4 to 20 carbon atoms, R is H, and
10 alkyl groups or those selected from the formula (R' is an alkyl group having 1 to 10 carbon atoms), and n and m are integers of 1 to 20. ] However, in () and (), [Formula] and (-CH ₂ CH ₂ O) _-n are combined randomly or in a block shape. 2. Agricultural use according to claim 1, wherein the polyhydric alcohol is a polyhydric alcohol selected from sorbitol, mannitol, glycerin, polyglycerin, pentaerythritol, and trimethylolpropane. Synthetic resin covering material. 3 Per 100 parts by weight of synthetic resin, the fluorine-containing compound represented by the general formula () and/or ()
The agricultural synthetic resin coating material according to claim 1, wherein the agricultural synthetic resin coating material is blended in a range of 0.01 to 2.0 parts by weight and an antifogging agent in a range of 1 to 5 parts by weight.