JPH01147A - Method for manufacturing agricultural film with excellent anti-fog and anti-fog properties - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an agricultural film used for growing agricultural crops out of season. Specifically, the present invention relates to an agricultural film that does not generate fog in an agricultural greenhouse and exhibits excellent antifogging properties over a long period of time.

[Prior Art] In recent years, crop cultivation has been widely practiced in agricultural greenhouses, tunnels, etc. using synthetic resin films for the purpose of early growth or out-of-season growth of crops.

These synthetic resin films include polyethylene films and polyvinyl chloride films, and polyvinyl chloride films are mainly used.

However, since the surface of these synthetic resin films is hydrophobic, if they are used as is, water vapor evaporated from the ground surface or crop bodies in agricultural greenhouses or tunnels will condense on the film surface and attach as water droplets, so-called wetting. This results in significant clouding of the film surface without showing any symptoms.

As a result, the penetration of sunlight becomes poor and the temperature rise inside the greenhouse decreases, significantly inhibiting the growth of crops.

To solve these problems, antifogging agents containing surfactants as a main component are added to agricultural films currently in use.

Agricultural films to which antifogging agents are added have a hydrophilic surface, and adhering water droplets exhibit a wetting phenomenon, immediately expanding onto the film surface and flowing down, keeping the film surface transparent. It will be done.

However, agricultural films to which the above-mentioned antifogging agent has been added have good sunlight penetration and excellent temperature-raising effects, but have the disadvantage that fog tends to form inside greenhouses. When fog occurs inside a greenhouse, it wets the leaves, flowers, stems, etc. of cultivated crops, causing diseases such as gray mold and vine blight, and reducing the yield of crops. The visibility is extremely poor, resulting in disadvantages such as reduced work efficiency.

The second fog phenomenon is often observed from late autumn to winter when the outside temperature is low in the mornings and evenings.

The direct cause of such occurrence in a commercial greenhouse is that the water vapor inside the greenhouse reaches a saturated vapor pressure or higher due to the temperature difference between the inside and outside of the greenhouse.

In other words, early morning fog occurs when water vapor that evaporates from the ground surface inside the greenhouse comes into contact with the cold air above the greenhouse and condenses into water droplets, forming fog. Further, evening fog is caused by nearly saturated water vapor inside the house condensing as the temperature above the house falls, turning into water droplets and becoming fog. Furthermore, the amount of fog and factors that promote fog generation will be considered.

One reason is the presence of condensation tuberculosis within the house.

It is surmised that the water vapor rising from the ground surface of the greenhouse is promoted to condense (formation of fog) using dust, etc. inside the greenhouse as a nucleus. This varies depending on the location and environment of the house. It is also thought that the degree of hydrophilicity of the film surface inside the greenhouse has an influence.

In other words, it is considered that the following three phenomena are constantly occurring on the film surface.

One is the flow of water condensed on the film surface due to the collision of water vapor evaporated from the ground surface of the greenhouse and the crop body, one is the rebound of the collided water vapor into the inside of the greenhouse, and one is the flow of water flowing down the film surface inside the greenhouse. This is a re-evaporation phenomenon.

The degree of hydrophilicity of the film surface is considered to be largely involved in how these phenomena are balanced, and is considered to be an important factor in determining the degree of fog generation.

Conventionally, various measures have been taken to suppress the formation of fog, such as reducing the temperature difference between the inside and outside of the house through ventilation, increasing the saturated water vapor pressure by heating the house, and using colored films. However, neither method was sufficient.

Also, the method of adding an organic siloxane surfactant described in JP-A No. 55-91663,
Methods such as adding a certain type of fluorine-based surfactant described in Publication No. 14648 have been proposed, but none of them completely suppresses the generation of fog, and even if they have a fog prevention effect, it is However, there still remain drawbacks such as a reduction in the long-term antifogging effect that is basically required for commercial films.

[Problems to be solved by the invention] The present inventors have solved the above-mentioned problem by preventing the formation of fog in agricultural greenhouses (
The present invention was achieved as a result of intensive research aimed at producing an agricultural film that exhibits excellent anti-fog properties over a long period of time.

[Means for Solving the Problems] The present invention provides a combination of a fluorine compound represented by the following general formula [I] and a sorbitan fatty acid ester [[I1] in a weight ratio of [I1·[■Koni50: 50 to 10:90] The present invention relates to a method for producing an agricultural film with excellent anti-fog and anti-fogging properties, characterized in that 1 to 5% by weight of the polyvinyl chloride resin is added.

- Monna [I]: % formula % (Rf is a perfluoroalkyl group having 6 to 10 carbon atoms, n
represents an integer from 5 to 30. ) The present invention will be explained in detail below.

Vinyl chloride resins used in the present invention include vinyl chloride homopolymer, vinyl chloride, vinyl acetate and its esters, acrylic acid and its esters, methacrylic acid and its esters, ethylene, propylene, vinylidene chloride,
Copolymers such as maleic acid and fumaric acid are included, and among them, vinyl chloride resin is preferred.

The fluorine compound represented by the above-mentioned Monana [I] used in the present invention is α obtained by ring-opening addition reaction with 2 moles of perfluoroalkylethanol and 1 mole of diglycidyl ether of polyethylene glycol having the following structure. It is an ωshiver fluoroalkyl compound.

In the above-mentioned hole [I], Rf is a perfluoroalkyl group having 6 to 10 carbon atoms, n is preferably in the range of 8 to 20 from the viewpoint of anti-fog properties, and n is smaller than 5 or exceeds 30. In the case of a compound, both fog-proofing properties and anti-fogging properties are poor, which is not preferable.

In addition, sorbitan fatty acid ester [I
I] is obtained by dehydrating 1 mole of sorbitol and 1 to 1.5 moles of higher fatty acids having 12 to 18 carbon atoms in a conventional manner. Examples include fatty acids, lauric acid, myristic acid, valmitic acid, stearic acid, and oleic acid, but palmitic acid and stearic acid are preferred in terms of effectiveness.

The number of moles of higher fatty acids per mole of sorbitol is 1 to 1
．． The amount is in the range of 5 moles, and if it exceeds 1,5 moles, the antifogging property becomes poor, which is not preferable.

In the present invention, when the compound represented by Mon'ena [I] and the sorbitan fatty acid ester [■] are each added alone to a vinyl chloride resin, the compound of Mon'ena [I] has antifogging and antifogging properties. Furthermore, although sorbitan fatty acid ester [I1] exhibits an antifogging effect, it does not have antifogging properties and cannot be put to practical use.

However, it is an IA industrial film that exhibits excellent anti-fogging and anti-fog properties, which is the gist of the present invention, by using the compound of Monana [I1] and a specific sorbitan fatty acid ester [■] in a specific ratio. 1. The reason why synergistically excellent anti-fog and anti-fogging properties are exhibited by the combined use of the compound of general formula [I1 and the specific sorbitan fatty acid ester [II] in a specific ratio is as follows. Although it has not yet been elucidated, the inventors of the present invention have speculated as follows based on the knowledge obtained from many years of research experience on antifogging agents for agricultural films. In other words, considering the above-mentioned fog generation mechanism, in order to suppress fog generation, it is essential to maintain the water vapor concentration above the inside of the house below the saturated vapor pressure. The key is to quickly condense, diffuse, and flow down the film surface.

The factor that determines the speed from the collision of this water vapor to the time it succumbs to the flow is the degree of expansion of the water droplets condensed on the film surface.

This degree is influenced by the state of the antifogging layer formed on the film surface. By using the α,ω shiver fluoroalkyl compound of general formula [I1] having a polyoxyethylene chain, which is a hydrophilic group, in the center of the molecule together with a specific sorbitan fatty acid ester, the above-mentioned anti-fogging property with good expansion of water droplets can be obtained. It is assumed that a layer is formed.

Furthermore, the reason for the excellent anti-fogging durability is also explained by the general formula [I
It is presumed that there is a mutual effect due to the combined use of the compound [I1] and sorbitan fatty acid ester [I1].

In addition, the total amount of the compound of the general formula [I1 and sorbitan fatty acid ester [nl] for vinyl chloride resin is 1 to 1.
It is preferably 5% by weight, and addition of more than 5% by weight does not improve performance significantly and is economically disadvantageous.

As is well known, the agricultural film of the present invention is made of soft vinyl chloride, and is usually 30 to 30 parts by weight per 100 parts by weight of vinyl chloride resin.
70 parts by weight of plasticizer is used as appropriate, and stabilizers, lubricants,
Ultraviolet absorbers, antioxidants, colorants, etc. are used as necessary. Thus, the vinyl chloride resin composition containing the above-mentioned components is formed into a film by a known method such as calendering or melt extrusion.

[Effects of the Invention] The present invention provides an agricultural film that has both excellent anti-fog and anti-fog properties by blending and using a specific fluorine compound and a specific sorbitan fatty acid ester in a specific ratio. . That is, by using the agricultural film of the present invention, it is possible to completely prevent the formation of fog, which is often observed in greenhouses from late autumn to winter, and eliminate the above-mentioned adverse effects caused by fog formation. At the same time, the agricultural film of the present invention exhibits excellent antifogging properties over a long period of time, making it very effective for facility cultivation such as out-of-season cultivation of crops.

[Examples] The present invention will be explained below using Examples, but the present invention is not limited to these Examples.

Example 1 100 parts by weight of vinyl chloride resin (degree of polymerization 1100), 4511 parts of dioctyl phthalate, epoxidized soybean oil
2 parts by weight, 5 parts by weight of tricresyl phosphate, Ba
-1 part by weight of Zn-based metal soap, 0.5 part by weight of methylene bisstearylamide and composition A2 of the present invention shown below.
Parts by weight were mixed to prepare a 100 micron film using a calendar roll.

Composition A of the present invention is a composition consisting of the following [+] and [II].

......20 parts by weight Sorbitan palmitic acid (1.2 mol) ester [0]
......80 overlapping sections This film was stretched on a frame assembled above an outdoor temperature-controlled aquarium to create an experimental greenhouse.

Observation of fog generation status and evaluation of antifogging properties were performed using the following methods.

Fog observation method Tests began in late October. In the morning and evening when the temperature drops, the water temperature in the water tank provided in the experimental greenhouse was set to 40°C, and the formation of fog in the greenhouse was observed for about 2 hours.

The aquarium was left alone except for the time when the fog was observed. This observation was carried out periodically until March.

The degree of fog generation was expressed using the following criteria.

◎　・・・No fog generation was observed.

○: Slight occurrence of fog is observed.

Δ...Fog formation is observed.

×: Significant fog formation is observed.

In parallel with the observation of back steam fog, the anti-fogging properties of the inner surface of the film placed in the experimental greenhouse were observed over a period of 10 months.

Antifogging properties were evaluated based on the following criteria.

◎　・・・Condition where no water droplets are observed.

O: Slight adhesion of water droplets is observed.

Δ: Condition where water droplets are observed.

×...Condition where a considerable amount of water droplets are observed.

XX...Condition where water droplets are observed over the entire surface.

Examples 2 to 5 Films to which the following constituents B to E of the present invention were added were prepared in the same manner as in Example 1, and Examples 2 to 5 were obtained.
Table 1 summarizes the evaluation results.

Composition B2...10 parts by weight Sorbitan stearic acid (1.2 mol) ester [I1
] ...90i parts composition
C: c, p,,c,H,OCH,CHCH,O(C,H4
0),,CH,CHC)l,QC,H,C,F,.

□HOH[I] 40 parts by weight Sorbitan stearic acid (1.3 mol) ester [I1
1...40 parts by weight Sorbitan palmitic acid (1.3 mol) ester [I1]...
...20 parts by weight Composition Leaves...10 parts by weight Sorbitan palmitic acid (1.2 mol) ester [0]
...90 parts by weight Composition E
: ......20 parts by weight Sorbitan lauric acid (1.5 mol) ester [01.
......10 parts by weight Sorbitan palmitic acid (1.3 mol) ester [I1
70 parts by weight Comparative Example 1 Comparative Example 1 was obtained by preparing a film in which the amount of Composition A added was 0.5 parts by weight in the same manner as in Example 1.

Comparative Example 2 In the same manner as in Example 1, a film was prepared in which a composition B was added in which the blending ratio of the fluorine compound [I1 and sorbitan fatty acid ester [I] according to the present invention was outside the range of the present invention. Comparative Example 2 was obtained.

Composition B.

......5 parts by weight Sorbitan stearic acid (1.2 mol) ester [I1
] ・・・・・・95 parts by weight Comparative example
3 In the same manner as in Example 1, the fluorine compound according to the present invention [! ] and sorbitan fatty acid ester [[I] A film was prepared by adding a composition E'' in which the blending ratio of sorbitan fatty acid ester [[I] was outside the range of the present invention, and Comparative Example 3 was obtained.

Composition E' 70 parts by weight Sorbitan lauric acid (1.5 mol) ester [I1]
・・・・・・・・・ 5 parts by weight Sorbitan balmitic acid (1.3 mol) ester [■1 ・
......25 parts by weight Comparative Example 4 to Comparative Example 6 The following compositions other than the present invention F to Comparative Example 6 were prepared in the same manner as in Example 1.
Comparative Examples 4 to 6 were obtained by creating films to which Composition H was added.

Composition F 20 parts by weight Sorbitan balmitic acid (1.2 mol) ester [nl
......80 parts by weight Composition G...25 parts by weight Sorbitan stearic acid (1°1 mol) ester [I1
] ・・・・・・・・・75 parts by weight Composition H ・・・・・・・・・30 parts by weight Sorbitan balmitic acid (2 mol) ester [■]・
70 parts by weight Table 11 The results of Examples and Comparative Examples are shown, and it is clear that the Examples of the present invention exhibit superior effects compared to the Comparative Examples.

Patent applicant: Toho Chemical Industry Co., Ltd.

Claims (2)

[Claims] (1) A fluorine compound represented by the following general formula [I] and sorbitan fatty acid ester [II] are combined into [I]:[II]
A method for producing an agricultural film with excellent anti-fog and anti-fogging properties, characterized by adding 1 to 5% by weight of vinyl chloride resin at a weight ratio of 50:50 to 10:90. General formula [I]: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (Rf is a perfluoroalkyl group having 6 to 10 carbon atoms, n
represents an integer from 5 to 30. ) (2) The method for producing an agricultural film according to claim (1), wherein the sorbitan fatty acid ester is obtained by reacting 1 mole of sorbitol with 1 to 1.5 moles of a higher fatty acid having 12 to 18 carbon atoms.