JP3358211B2 - Agricultural soft vinyl chloride resin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft vinyl chloride resin film for agricultural use which does not stick to each other at the time of secondary processing and house stretching and has good transparency after stretching.

[0002]

2. Description of the Related Art A soft vinyl chloride resin film for agricultural use in which a plasticizer is blended with a vinyl chloride resin is generally manufactured continuously by an extrusion molding method, a calendar molding method, or the like.
After being wound into a roll, it is transported, stored, and used.
The so-called secondary processing such as welding processing is performed while rewinding the film from a wound film wound into a roll.

[0003] However, since the film contains a large amount of plasticizer, the film surface shows tackiness,
The film wound in a roll form has a problem that the surfaces easily adhere to each other, and the product obtained by the secondary processing has a problem that the surfaces adhere to each other and workability such as stretching work is extremely poor. Conventionally, in order to solve this problem, a method of embossing the film or blending a large amount of solid fine particles to roughen the surface and reduce the adhesiveness of the film, A method of spraying starch or the like to prevent sticking has been used.

[0004]

However, a method of reducing the tackiness by embossing the film or blending a large amount of solid fine particles in the film impairs the transparency of the film and reduces the crop in the house. There was a drawback that it could not be seen from the outside. Also, in the method of spraying starch and the like to prevent sticking, the transparency of the film is restored because the starch and the like are removed by rainwater or water drops generated in the house in a short period of time. When a fine powder for preventing sticking, such as starch powder, is sprayed on the film surface at the secondary processing plant, the fine powder is not only scattered in the air, significantly deteriorating the working environment, but also causing a loss of the fine powder. There was a disadvantage of being large. Therefore, as a means for solving this drawback, a method of spraying an anti-adhesive such as starch and talc on the surface of the film immediately before winding the film into a roll at the time of film production can be considered. The relatively large particles of the powder have the disadvantage that the particles are difficult to be wound on the film surface after winding and the surface smoothness of the film is impaired.Also, the talc is not affected by rainwater or the flow of water droplets generated in the house. And the transparency of the film is hardly restored.

Further, it is difficult to uniformly deposit fine powders of silicon oxide, calcium carbonate, etc. on a film as it is, especially when the particle diameter is small, aggregation tends to occur and poor dispersion occurs. There was a problem of doing. The present invention has been made in order to overcome the above problems, without spraying starch or the like in a secondary processing plant, preventing the film from sticking, and recovering transparency after spreading for agricultural use. It is intended to provide a soft vinyl chloride resin film.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention resides in that at least one surface of a soft vinyl chloride resin film is coated with an inorganic fine powder having an average particle diameter of 0.2 to 10 μm and non-adhesive at room temperature. of a mixture of water-soluble polymer, Fi
It is a vinyl chloride resin film for agricultural use that is attached at a ratio of 3 to 50% based on the surface area of the lum . Less than,
The present invention will be described in detail.

In the present invention, as the vinyl chloride resin, in addition to polyvinyl chloride, a copolymer of polyvinyl chloride with another comonomer mainly containing vinyl chloride, a mixture thereof, or a mixture of these with another polymer or copolymer Can be used. The soft vinyl chloride resin film of the present invention,
It contains 30 to 100 parts by weight of a plasticizer per 100 parts by weight of a vinyl chloride resin, and other various resin additives that are usually blended into agricultural films as required, for example, a drip-free agent, a lubricant, and an anti-fog. Agents, warming agents, antioxidants, ultraviolet absorbers, light stabilizers, dyes, pigments, and the like can be compounded. These additives are used in a usual amount, for example, with respect to 100 parts by weight of a vinyl chloride resin. It can be used up to 10 parts by weight. In addition, in order to mix a plasticizer and various resin additives with the vinyl chloride resin, a conventional mixing technique, for example, a ribbon blender, a Banbury mixer, a super mixer, and other known mixers may be used. T-die method to make vinyl resin mixture into film
Techniques such as an extrusion molding method such as an inflation method, a calendar molding method, and a casting method can be used. Further, the surface of the film may be covered with an acrylic resin or the like by a gravure coating method, a reverse coating method, or the like.

The inorganic fine powder used in the present invention includes magnesium carbonate, silicon oxide, aluminum oxide, barium sulfate, calcium sulfate, magnesium hydroxide, aluminum hydroxide, calcium carbonate, zinc oxide and the like. Or two or more of them may be used in combination. The inorganic fine powder has an average particle diameter of 0.2 to 10 μm, particularly preferably 1 to 5 μm. When the average particle diameter of the inorganic fine powder is larger than 10 μm, even if the inorganic fine powder is uniformly adhered to the film surface, the particles are hardly wound on the film surface due to the winding pressure during the process of winding and storing the film in a roll shape, and the film surface has a grain shape ( This is a state in which small irregularities are formed on the surface), the smoothness is lost, and the transparency is lowered. On the other hand, when the average particle diameter is smaller than 0.2 μm, the inorganic fine powder may aggregate to form large particles or uneven distribution of particles on the film.

The adhesion amount of the inorganic fine powder is 0.01 to 1 g / m ² , especially 0.05 to 0.5 g per unit area of the film.
/ M ² . When the adhesion amount is less than 0.01 g / m ² , there is almost no anti-adhesion effect, and 1 g / m ²
If it is larger, the fine powder is partially deposited on the surface of the film, and the smoothness of the film surface may be impaired. Furthermore, a small amount of a known anti-blocking agent such as starch or talc can be mixed into the inorganic fine powder to be adhered to the film surface, and the mixing ratio in this case depends on the degree of tackiness. Can be selected as appropriate.

Next, water-soluble polymers that are non-adhesive at room temperature include polyvinyl alcohol (hereinafter referred to as PVA), polyethylene oxide, sodium polyacrylate, water-soluble celluloses such as carboxymethyl cellulose, and the like.
Soluble starches such as hydroxyethylcellulose, alkylcellulose and viscose include carboxymethyl starch and dialdehyde starch.

Even if these water-soluble polymers are used alone,
Two or more kinds may be used in combination. Further, the adhesion ratio between the inorganic fine powder and the water-soluble polymer is preferably 1:10 to 10: 1 by weight, and more preferably 3: 7 to 7: 3. When the ratio of the inorganic fine powder is more than 10: 1, the outflow of the deposits due to rainwater or the like is inferior. When the ratio is less than 1:10, the effect of improving workability is not seen.

The ratio of the mixture of the inorganic fine powder and the water-soluble polymer which is non-adhesive at room temperature adheres to the film surface is as follows:
The content is preferably from 3 to 50%, more preferably from 5 to 30%, based on the area of the film surface. If the ratio of the mixture adhering is less than 3%, the effect of improving workability is not seen, and if it is more than 50%, the outflow of the mixture due to rainwater or the like is inferior. Note that the mixture may be evenly attached to the entire surface of the film, but the area occupied by the attached matter in the sewn portion may be reduced in consideration of suturing by a high-frequency sewing machine or a high-frequency welder.

It is preferable that the average height (roughness) of the deposits on the film surface from the film surface is 1 to 10 μm. The average height (roughness) from the film surface is 1 μm
If it is smaller, the effect of improving workability may be reduced, and if the average height is larger than 10 μm, the film is hardly wound on the film due to the winding pressure during the process of winding and storing the film in a roll shape, and the film surface may be damaged. It is not preferable because it becomes grain-like, loses smoothness, and lowers transparency.

The ratio of the mixture adhering to the film surface and the average height of the adhering matter are determined by adjusting the total concentration of the inorganic fine powder and the water-soluble polymer in the dispersion and the spray amount of the dispersion. , Can be controlled. Further, if necessary, the mixture is a small amount of an acid or alkali, an antifoaming agent, a surfactant, an antistatic agent, an antioxidant, an ultraviolet absorber, a pigment, to such an extent that recovery of transparency is not hindered. Additives such as fungicides and anti-algal agents can be mixed.

In order to attach a mixture of the inorganic fine powder and the water-soluble polymer to the film, usually, a dispersion of this mixture is sprayed on the film by a rotating drum, a two-fluid nozzle, or the like, or a gravure coating method. Alternatively, the film may be applied by a reverse coating method or the like, and then dried by a natural drying method or a forced drying method using hot air or infrared irradiation. As the dispersion medium, water, an organic solvent such as an alcohol capable of dissolving a water-soluble polymer, or a mixture thereof can be used.

Further, a mixed fine powder obtained by mixing an inorganic fine powder and a water-soluble polymer fine powder, or a fine powder obtained by surface-treating an inorganic fine powder with a water-soluble polymer is subjected to an electrostatic duster method utilizing electrostatic charging. It may be attached. After adhering the mixture on the film surface, the film is conventionally known film winding method, for example, a center winder,
The product is wound up by a surface winder or the like to form a roll-shaped product.

The thickness of the film is preferably in the range of 0.03 to 0.3 mm in consideration of strength, production cost and the like. Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist is not exceeded.

[0018]

【Example】

 Examples 1 to 11, Comparative Examples 1 to 9

(1) Production of a soft vinyl chloride resin film Polyvinyl chloride (degree of polymerization = 1300) 100 parts by weight Di-2-ethylhexyl phthalate 50 parts by weight Tricresyl phosphate 5 parts by weight Epoxy resin 2 parts by weight Ba -Zn liquid stabilizer 2 parts by weight Ba-Zn powder stabilizer 2 parts by weight Sorbitan monopalmitate 1.5 parts by weight Benzophenone type ultraviolet absorber 0.2 parts by weight

The above-mentioned resin raw materials and resin additives are weighed, stirred and mixed with a supermixer for 10 minutes, kneaded on a roll heated to 165 ° C., and a width of 100 cm and a thickness of 100 cm by an L-type calender. 0.075m
m of a transparent soft vinyl chloride resin film.
Further, the film after coming out of the calender roll was brought into contact with a cooling roll to cool the film to 80 ° C. or lower. Next, as shown in Table 1, various inorganic fine powders and water-soluble polymers were weighed in predetermined amounts, and water was added to adjust the total concentration and spray amount of the inorganic fine powders and the water-soluble polymer, and The film was sprayed on both sides of the film using a drum type spray machine (Rotor Dampening, manufactured by Nikka Riken Co., Ltd.). The occupied area and average height of the deposit on the film surface are as follows:
Electron beam three-dimensional roughness analyzer (manufactured by Elionix Inc., E
RA-8000). After spraying, it was air-dried or forced-dried in a drying zone and wound up in a roll with a surface winder. (However, it was not sprayed in Comparative Example 9.) As the water-soluble polymer, polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol A-3)
00, hereinafter abbreviated as A-300) or methyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd., Metrose 60SH, hereinafter 6)
OSH).

(2) Evaluation of Adhesiveness, Surface Smoothness, and Transparency after Running Water The 20 kinds of films wound up in the form of a roll in (1) were kept in a roll form at a temperature of 40 ° C. and a relative humidity of 70%.
After standing for 2 weeks in an atmosphere having the following conditions, the film was evaluated for tackiness, surface smoothness, and transparency after flowing water by the following method. The results are shown in Table 1.

[0021]

[Table 2]

Evaluation of Adhesiveness A film of 40 cm square was cut out from the roll-shaped material, and the film was folded into four pieces and stacked.
The film was left for 24 hours in an atmosphere maintained at 0 ° C., the load was removed, and the state of adhesion between the film surfaces when the film was unraveled was observed. The evaluation results shown in Table 1 have the following meanings. ○: Little adhesiveness △: Some adhesiveness ×: Notable adhesiveness

After the evaluation of the adhesiveness by the evaluation of the surface smoothness, the film was washed with water and the surface of the film was visually observed. The evaluation results shown in Table 1 have the following meanings. …: The surface is extremely smooth △: slight unevenness is observed on the surface ×: considerable unevenness is observed on the surface

Evaluation of Transparency after Flowing Water A film of 40 cm square was cut out from the roll, and this was spread on the ceiling of a water tank shown in FIG. 1 and having a 30 ° ceiling angle and containing warm water. The water tank was sealed. The whole of the water tank was placed in a constant temperature chamber, warm water was kept at 45 ° C., and the temperature of the constant temperature chamber (outside air temperature of the water tank) was kept at 20 ° C., and treatment was performed for 6 hours.

Next, the film was turned upside down, the water tank was closed again, and the film was treated under the same conditions for 6 hours. After the treatment, the film was removed and dried, and the transparency of the film was visually determined. The evaluation results shown in Table 1 have the following meanings. ○: good transparency △: slightly poor transparency ×: poor transparency

[0026]

The soft vinyl chloride resin film for agriculture of the present invention has almost no tackiness and good outflow of attached matter, so that it is not necessary to spray starch or the like during secondary processing. It also has good workability and can recover the original transparency of the film after stretching. Therefore, it can be spread on agricultural and horticultural facilities such as a house and a tunnel as an agricultural covering material, and can be used for cultivation of useful plants.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a water tank used in the evaluation of outflow of attached matter in Examples.

[Explanation of symbols]

 1 Water tank 2 Hot water surface position 3 Untreated film 4 Evaluation sample film

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI B32B 27/30 101 B32B 27/30 101 // C08L 27:06 C08L 27:06 (72) Inventor Miyuki Sato Nakamura, Nagoya-shi, Aichi No. 2, Oike, Iwazuka-cho, Ward Nagoya Plant of Mitsubishi Kasei Vinyl Co., Ltd. (56) References JP-A-3-180334 (JP, A) JP-A-60-6734 (JP, A) JP-A-60-8328 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08J ^7/ 04-7/06 B32B 27/00-27/42 A01G 9/14

Claims (6)

(57) [Claims] A mixture of an inorganic fine powder having an average particle diameter of 0.2 to 10 μm and a non-adhesive water-soluble polymer at ordinary temperature is coated on at least one surface of a soft vinyl chloride resin film.
Attached at a rate of 3 to 50% based on the surface area of
Vinyl chloride resin film for agricultural use. 2. The film according to claim 1, wherein the amount of the inorganic fine powder is 0.05 to 0.5 g / m ² per unit area of the film. 3. The adhesion ratio between the inorganic fine powder and the water-soluble polymer is as follows:
By weight, is 1: 10 to 10: 1, according to claim 1 or 2
Film. Wherein the water-soluble polymer is polyvinyl alcohol or a water-soluble cellulose ethers, any of claims 1 to 3
A film as described in Crab . 5. The average height of the film of the deposits 1
The film according to any one of claims 1 to 4 , which has a thickness of 10 µm. 6. The method according to claim 1, wherein the deposit comprises the inorganic fine powder and a water-soluble polymer.
Attached by spraying or applying a dispersion of the mixture of
The fill according to any one of claims 1 to 5, wherein
M