JPS61254648A - Vinyl chloride resin film for agricultural purposes - Google Patents

Abstract

PURPOSE:The title film that is obtained by adding a nonionic surfactant and a pentaerytheritol fatty acid ester, thus being able to avoid mist formation, when it is applied to green houses and the like, because it has excellent fog resistance and antiblocking properties. CONSTITUTION:(A) 100pts.wt. of a vinyl chloride resin are combined with (B) a dipentaerytheritol fatty acid ester of 12-18 carbon atoms and (B) a nonionic surfactant such as sorbitol fatty acid ester so that the amount of component A becomes 0.3-1pt.wt. per 1pt.wt. of component B and the sum-up of A+B becomes 1.5-3, preferably 2-2.5pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an agricultural vinyl chloride resin film and a method for preventing fog generation in an agricultural covered space such as an agricultural greenhouse. A vinyl chloride resin film that prevents fog generation in the covered space, has excellent antifogging properties, and has low adhesion between films (hereinafter referred to as anti-blocking property), and can be used to create a covered space for agricultural use. The present invention relates to a method of preventing fog in this space by forming a fog.

(Prior art) Agricultural vinyl chloride resin films have excellent weather resistance, heat retention, light transmittance, etc., and have traditionally been used in agriculture and horticulture to cover agricultural spaces in various forms such as greenhouses, tunnels, and frames. It is widely used as a covering film for so-called greenhouse cultivation, where crops are forced to grow inside the greenhouse. In such a vinyl chloride resin film, when the water vapor generated from the soil and crops in the greenhouse adheres to the surface as water droplets, it imparts hydrophilicity to the film surface and improves its compatibility with the water droplets. Non-ionic surfactants such as sorbitan fatty acid ester and glycerin fatty acid ester are usually used as anti-fogging agents to ensure the light transmittance of the film and facilitate temperature rise within the greenhouse. Contained as an agent.

However, in greenhouses made of vinyl chloride resin films containing antifogging agents, the cause is not necessarily clear, but problems often occur due to the narrow openings where the temperature difference inside the greenhouse is large, in the mornings and evenings in early spring, and during rainfall. It is already known that fog can occur inside the greenhouse. When fog occurs in a greenhouse, it wets the leaves, stems, fruits, etc. of cultivated crops, and helps the development and propagation of diseases such as gray mold and sclerotium, or it hinders the growth of crops by blocking the transmission of light. inhibit, etc.
Various problems arise.

In order to solve such problems, organic siloxane surfactants have already been introduced in Japanese Patent Application Laid-open Nos. 55-91663 and 1982-12070 to prevent the above-mentioned fog generation. An agricultural vinyl chloride resin film containing an additive, that is, an antifog agent, has been proposed, but when the film is stored for a long period of time,
Since the organic siloxane blooms, problems such as a decrease in high frequency processability occur. Also, Tokukai Showa 5? −
No. 3847 proposes a vinyl chloride resin film containing an ethylene oxide or propylene oxide adduct to sorbitan dehydrate fatty acid ester as a fog preventer. However, this film does not maintain its fog-proofing effect over a long period of time, and therefore cannot effectively prevent fog from occurring in greenhouses over a long period of time seasonally.

Furthermore, JP-A-57-08236 discloses an agricultural chloride compound containing a combination of a polyhydric alcohol ester of a linear higher fatty acid and a polyhydric alcohol ester of a branched higher fatty acid as a fog preventer. A vinyl resin film is described. However, although this film can provide some degree of antifogging properties, the antifogging properties are still insufficient.

Furthermore, anti-blocking properties are required as an important property for agricultural vinyl chloride resin films. for example,
When the films block each other, the workability when constructing a house by unfolding the folded film is significantly reduced. For this purpose, it is known that fatty acid amides such as methylene bisstearamide are added to improve anti-blocking properties, but when added in large amounts, blooming occurs and reduces the transparency of the film. This may cause problems such as causing problems.

As mentioned above, various proposals have been made to improve the properties of agricultural vinyl chloride resins, but they still have many problems, especially in terms of anti-fog, anti-fog and anti-blocking properties. A vinyl chloride resin film for agricultural use that has all of these properties at the same time is not yet known.

(Purpose of the Invention) As a result of intensive research in order to solve the various problems described above, the present inventors have discovered that a vinyl chloride resin film containing dipentaerythritol fatty acid ester together with a nonionic surfactant has a long-lasting effect. The present invention was developed based on the discovery that it not only can prevent the generation of fog in a greenhouse over many years, but also has excellent anti-fogging and anti-blocking properties.

That is, an object of the present invention is to provide an agricultural vinyl chloride resin film that can prevent fog generation for a long period of time and has excellent anti-fogging and anti-blocking properties. The purpose is to provide a fog prevention method in space.

(Structure of the Invention) The agricultural vinyl chloride resin film according to the present invention is characterized by containing a nonionic surfactant and dipentaerythritol fatty acid ester.

Further, the fog prevention method for an agricultural covered space according to the present invention is characterized in that the agricultural covered space is formed with an agricultural vinyl chloride resin film containing dipentaerythritol fatty acid ester and a nonionic surfactant. do.

In addition to polyvinyl chloride, the vinyl chloride resin used in the present invention includes a copolymer of vinyl chloride and a monomer copolymerizable with the vinyl chloride. Examples of such a copolymer include polyvinyl chloride. Examples include copolymers of vinyl chloride and one or more of vinylidene, ethylene, propylene, acrylic acid, methacrylic acid, acrylonitrile, maleic acid, itaconic acid, vinyl acetate, and the like.

The agricultural vinyl chloride resin film according to the present invention simultaneously contains a nonionic surfactant conventionally known as an antifogging agent and dipentaerythritol fatty acid ester.

Examples of the nonionic surfactants include sorbitan ester surfactants such as sorbitan monostearate and sorbitan monopalmitate, glycerin ester surfactants such as glycerin monolaurate and glycerin monostearate, and polyethylene glycol monostearate. Examples include polyethylene glycol ester surfactants such as, trimethylolpropane ester surfactants such as trimethylolpropane monostearate, and esters of sorbitan-glycerol condensates and fatty acids. In particular, in the present invention, a sorbitan fatty acid ester surfactant is preferably used in combination with a dipentaerythritol fatty acid ester because it provides a vinyl chloride resin film with excellent anti-fog properties and anti-fogging properties.

Next, the dipentaerythritol fatty acid ester used in the present invention is not particularly limited as long as it is a higher fatty acid ester of dipentaerythritol. For example, higher fatty acids include lauric acid, myristic acid, palmitic acid, or stearic acid. Preferably, the higher fatty acid has 12 to 18 carbon atoms, particularly preferably 14 to 16 carbon atoms, and the ester thereof is preferably mono- or diesterized. In dipentaerythritol higher fatty acid ester, when the number of carbon atoms in the higher fatty acid is less than 12, the anti-fog effect will not last long enough, whereas when the number of carbon atoms is more than 18, the anti-fog effect and the anti-fog effect will be insufficient. This is because there is a tendency for the clouding effect to decrease as well. Further, among the above esters, esters of triester or higher reduce the fog-proofing effect of the film, although the reason is not necessarily clear.

The above-described nonionic surfactant and dipentaerythritol fatty acid ester are preferably used in a total amount of 1.5 to 3.0 parts per 100 parts by weight of vinyl chloride resin.
0 parts by weight, particularly preferably 2.0=2. The dipentaerythritol fatty acid ester is preferably added in an amount of 0.3 parts by weight per 1 part by weight of the nonionic surfactant.
It is blended in an amount of ~1.0 parts by weight. If the amount of the nonionic surfactant and dipentaerythritol fatty acid ester is less than the above range, the resulting film will have poor anti-fog and anti-fog effects; on the other hand, if the amount exceeds the above range This is because blooming and other undesirable effects may occur depending on the combination with other additives.

The vinyl chloride resin film according to the present invention may contain various additives that are usually added to vinyl chloride resin films, such as plasticizers, stabilizers, lubricants, ultraviolet absorbers, pigments, etc., as long as their properties are not deteriorated. It may contain a gelling accelerator, an antistatic agent, an antifungal agent, and the like.

Examples of plasticizers include phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, and diisodecyl phthalate, isophthalic acid derivatives such as diisooctyl isophthalate, adipic acid derivatives such as dioctyl adipate, and others. Tricresyl phosphate, epoxidized soybean oil, etc. are used. The appropriate amount is 20 to 70 parts by weight per 100 parts by weight of the vinyl chloride resin.

Stabilizers include, for example, zinc stearate, barium stearate, calcium stearate, and barium ricinoleate; lubricants include, for example, bisamide,
Stearic acid, polyethylene wax, etc. are used in appropriate amounts. Further, as the ultraviolet absorber, benzotriazole type, benzoate type, benzophenone type, cyanoacrylate type, phenyl salicylate type, etc. are used, and as the pigment, for example, ultramarine blue, phthalocyanine blue, carbon black, titanium oxide, etc. are used. However, the above additives are merely examples, and the present invention is not limited thereto.

The agricultural vinyl chloride resin film according to the present invention is produced by melt extrusion, calendering, etc. in the same manner as conventional vinyl chloride resin films, and its thickness is not particularly limited, but is usually 25 to 25 mm thick. It is 300 μm.

(Effects of the Invention) As described above, the agricultural vinyl chloride resin film according to the present invention contains dipentaerythritol fatty acid ester together with a nonionic surfactant, and has long-term fog-proofing and anti-fogging properties. In particular, if various forms of agricultural covered spaces such as greenhouses, tunnels, frames, etc. for forced cultivation of crops are formed inside the space, fog will not be generated within the space, and The transparency of the film can be ensured for a long period of time, and therefore, an agricultural covered space with excellent growth performance of crops can be obtained.

Furthermore, in the past, a lubricant such as methylene bisstearoide amide was added to vinyl chloride resin in order to improve anti-blocking properties, but according to the agricultural vinyl chloride resin film of the present invention, this Even without the addition of lubricants, it has sufficiently good anti-blocking properties and is excellent in workability in constructing greenhouses, etc.

Furthermore, the agricultural vinyl chloride resin film of the present invention has good adhesion with a high-frequency sewing machine, and does not impair the properties of the vinyl chloride resin, such as heat retention and transparency, during various processing.

In addition, the dipentaerythritol fatty acid ester used in the present invention is not only less expensive than organic polysiloxanes and fluorine-based surfactants, but also has the above-mentioned excellent properties by blending only a small amount with vinyl chloride resin. fog-proof,
Since it is possible to impart anti-fogging and anti-blocking properties to the film, it is not only inexpensive to produce, but also
Problems such as blooming of these additives on the film surface do not occur.

(Examples) The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples in any way. In the following, parts mean parts by weight.

Example 100 parts of polyvinyl chloride (average degree of polymerization 1300), 47 parts of dioctyl phthalate, 3 parts of tricresyl phosphate
1 part, 2 parts of Ba-Zn composite stabilizer, 1.5 parts of sorbitan monopalmitate, and dipentaerythritol fatty acid ester shown in Table 1 was calendered to obtain a film having a thickness of 100 μm.

For comparison, a film containing no dipentaerythritol fatty acid ester and a film containing methylene bisstearamide instead of the dipentaerythritol fatty acid ester were prepared in the same manner as above. Furthermore, instead of dipentaerythritol fatty acid ester,
A film with added pentaerythritol monopalmitate was prepared in a similar manner.

Each of the agricultural vinyl chloride resin films obtained in this way was evaluated for antifogging properties, antifogging properties, and antiblocking properties. The results are shown in Table 1.

In addition, evaluation of anti-fog properties and anti-fogging properties was performed as follows. That is, a film is placed on the frame and side surfaces of a rectangular frame, placed on a pre-prepared thermostatic water bath with a temperature of about 50°C, and heated to 25°C.
It was left at room temperature for a specified period of time.

Thereafter, the water temperature in the thermostatic water tank was lowered to about 25° C., and the room temperature was lowered to 15° C., and after being left for 60 minutes, the fog generation status was visually observed. The evaluation criteria are as follows.

◎ No fog generation was observed.

○ A very slight amount of fog is observed.

Mouth: A slight amount of fog is observed.

× A large amount of fog was observed.

Regarding the antifogging property, the adhesion of water droplets to the film surface was examined under the same conditions as above, and evaluated using the following criteria.

◎ No water droplets adhere at all.

○ Slight water droplets adhere.

In addition, in order to evaluate the anti-blocking property, two sheets of each of the sample films obtained above were cut into a size of 25 x 50 cm and stacked on top of each other, and a load of 2 kg was applied on top of the film at a temperature of 50°C and a humidity of 50°C. Place it in a 95% constant temperature chamber,
After 24 hours, it was cooled to room temperature, and the force required to separate the two stacked films was measured using a Schopper tensile tester.

As shown in Table 1, the agricultural vinyl chloride resin film of the present invention has excellent fog-proofing and anti-fogging properties.
Moreover, these effects are sustained over a long period of time.
It also has good anti-blocking properties and is comparable to conventional greenhouse cultivation films.

Next, using the films of Example Experiment No. 5.7.8 and Comparative Example Experiment No. 2 created above, the outdoor depth was 22 mm.
A test house with a width of 4 m and a ridge height of 3.2 m was constructed, and a film was spread on the house. After 60 days, the situation of fog in the house and the surface of the film were measured at around 8 a.m. for several days. Clouding was observed, and the antifogging and antifogging properties of the film were evaluated in the same manner as described above.

Furthermore, anti-blocking properties were evaluated based on the ease of handling during expansion using the following criteria.

○ Can be easily expanded.

× Difficult to expand.

Table 2 The results are shown in Table 2. For Example Experiment No. 7, slight fog formation and cloudiness due to water droplets were observed, but for the other 5 and 8, no fog formation or cloudiness was observed. Ta. Further, in all of the examples, the extensibility was good.

Claims (8)

[Claims] (1) An agricultural vinyl chloride resin film containing dipentaerythritol fatty acid ester and a nonionic surfactant. (2) Contains 0.3 to 1.0 parts by weight of dipentaerythritol fatty acid ester per 1 part by weight of nonionic surfactant, and contains dipentaerythritol fatty acid ester and nonionic surfactant per 100 parts by weight of vinyl chloride resin. The agricultural vinyl chloride resin film according to claim 1, which contains a total of 1.5 to 3.0 parts by weight of a surfactant. (3) The agricultural vinyl chloride resin film according to claim 2, wherein the dipentaerythritol fatty acid ester is a mono- or diester of dipentaerythritol with a fatty acid having 12 to 18 carbon atoms. (4) The agricultural vinyl chloride resin film according to claim 1 or 2, wherein the nonionic surfactant is sorbitan fatty acid ester. (5) A fog prevention method for an agricultural covered space, which comprises forming the agricultural covered space with an agricultural vinyl chloride resin film containing a dipentaerythritol fatty acid ester and a nonionic surfactant. (6) The agricultural vinyl chloride resin film contains 0.3 to 1.0 parts by weight of dipentaerythritol fatty acid ester per 1 part by weight of nonionic surfactant, and contains dipentaerythritol fatty acid ester per 100 parts by weight of vinyl chloride resin. 6. The method for preventing fog in an agricultural covered space according to claim 5, which contains a total of 1.5 to 3.0 parts by weight of a pentaerythritol fatty acid ester and a nonionic surfactant. (7) The method for preventing fog in an agricultural covered space according to claim 6, wherein the dipentaerythritol fatty acid ester is a mono- or diester of dipentaerythritol with a fatty acid having 12 to 18 carbon atoms. (8) A fog prevention method for an agricultural covered space according to claim 5 or 6, wherein the nonionic surfactant is a sorbitan fatty acid ester.