JPH04237438A - Production of agricultural vinyl chloride-based resin film - Google Patents

Abstract

PURPOSE:To provide a film excellent in operating efficiency without requiring a conventional method for scattering starch, etc., for preventing tacking in secondary processing of the film. CONSTITUTION:An agricultural vinyl chloride-based resin film improved in tackiness is produced by a method for forming a soft vinyl chloride resin composition into a film, scattering and applying fine silica powder having 1-5mum average grain diameter and >=1ml/g apparent specific volume to the surface of the film before winding the resultant film.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing agricultural vinyl chloride resin films. More specifically, the present invention relates to a method for producing an anti-stick agricultural vinyl chloride resin film that recovers transparency after being stretched.

0002

[Prior Art] Agricultural vinyl chloride resin film, which is made by blending a large amount of plasticizer with vinyl chloride resin, is generally produced continuously by extrusion molding or calendar molding, and the film is wound into a roll. transported, stored, and used. Agricultural vinyl chloride resin film is unwound from a roll-shaped film and subjected to so-called secondary processing such as welding processing. On the other hand, agricultural vinyl chloride resin films made by blending 30 PHR or more of plasticizer into the base vinyl chloride resin have adhesive surfaces, and the surfaces of the films wound into rolls tend to stick to each other. easy. In addition, the surfaces of products obtained by secondary processing adhere to each other, resulting in extremely poor workability in stretching operations and the like. Therefore, during secondary processing, starch powder or the like is sprinkled to prevent stickiness. In addition, the starch powder can be removed from the film sprinkled with starch powder by rainwater or water droplets generated in the greenhouse within a short period of time, and the transparency can be restored. However, when dusting anti-adhesive powders such as starch powder on the film surface at secondary processing plants, not only do the fine powders scatter into the air, making the working environment extremely bad, but there is also a large loss of fine powders. There is a problem. Therefore, as a means to eliminate the above problem, there is a method of spraying an anti-blocking agent such as starch powder or talc on the surface of the film just before winding it into a roll, but since the particles of starch powder are relatively large, After winding, particles become embedded in the film surface, impairing the film's surface smoothness, and talc is difficult to remove from the film surface by rainwater or water droplets generated within the greenhouse, resulting in poor transparency. be.

0003

[Problems to be Solved by the Invention] The present invention improves adhesion and solves the problem of poor transparency after spreading by scattering a specified fine silica powder when winding up an agricultural vinyl chloride resin film. The purpose is to

0004

[Means for Solving the Problems] The present invention involves forming a resin composition containing 30 to 100 parts by weight of a plasticizer per 100 parts by weight of a vinyl chloride resin into a film, and, before winding it into a roll, at least one side of the film. This is a method for producing an agricultural vinyl chloride resin film with improved adhesiveness, characterized in that fine silica powder with an average particle diameter of 1 to 5 μm and an apparent specific volume of 1 ml/g or more is spread and adhered to the film. .

The present invention will be explained in detail below. In the present invention, vinyl chloride resin refers to polyvinyl chloride, a copolymer mainly composed of vinyl chloride with other comonomers, a mixture thereof, or a mixture of these and other polymers or copolymers. . In addition to plasticizers, which are generally used in agricultural vinyl chloride resin films, vinyl chloride resins also contain various usual resin additives, such as antifogging agents, lubricants, antioxidants, ultraviolet absorbers, and light absorbers. Stabilizers, dyes, pigments, etc. can be added. These additives are added in the usual amount, for example, per 100 parts by weight of vinyl chloride resin.
It can be used in an amount of 10 parts by weight or less. To blend plasticizers and various resin additives into the base vinyl chloride resin, use conventional mixing and blending techniques such as a ribbon blender, Banbury mixer, super mixer, and other conventionally known blenders and mixers. good. To form a film from the vinyl chloride resin composition, techniques such as extrusion molding methods such as T-die method and inflation method, calender molding method, and casting method can be employed. The fine silica powder is sprinkled on at least one surface of the film before the film is wound into a roll. Spraying methods include an electrostatic duster method using electrostatic charging of the fine silica powder, and a spray method of an aqueous dispersion of the fine silica powder. The silica to be sprayed can be used as it is or after being subjected to a commonly used surface treatment using silicone oil, fluorine compounds, etc. The average particle size of the silica fine powder to be sprinkled is 1 to 5.
μ. If the average particle diameter is smaller than 1μ, the particles tend to aggregate with each other, and the adhesion between the particles and the film base material becomes strong, making it difficult to peel off from the film surface, and the transparency after running water is poor, which is undesirable. . If the average particle size is larger than 5μ, even if the particles are evenly deposited on the film surface, the winding pressure during the process of winding the film into a roll and storing it will cause the particles to become embedded in the film surface, leaving the film surface grainy (small irregularities on the surface). is formed.), and
This is not preferable because smoothness is lost and transparency is reduced.

[0006] Also, the apparent specific volume of fine silica powder is 1 ml.
/g or more. If the apparent specific volume is less than 1 ml/g, not only will there be little effect on preventing adhesion on the film surface unless a large amount is deposited, but the deposits will be difficult to peel off from the film surface due to rainwater or water droplets generated in the greenhouse, and transparency will decrease. does not recover. The amount of adhesion to the film surface depends on the type of plasticizer added to the film, the amount of plasticizer added,
Various values can be selected depending on the secondary processing method of the film, etc., and it is preferably in the range of 0.01 g/m2 to 2 g/m2, and more preferably 0.1 g/m2 to 1 g/m2.
is particularly preferred. If the adhesion amount is less than 0.01g/m2, there will be little effect on preventing adhesion on the film surface.
If the amount is more than 2 g/m2, the amount of adhesion is too large and the fine powder is partially deposited on the film, impairing the smoothness of the film surface, which is not preferable.

[0007] The fine silica powder to be sprinkled on the surface of the film may be mixed with a small amount of a conventionally known anti-blocking agent such as starch or talc. In this case, the mixing ratio can be appropriately selected depending on the degree of stickiness. After the fine silica powder is sprinkled on the surface of the film, the film is wound up using a conventionally known film winding method, such as a center winder or a surface winder, to form a roll-shaped product. In addition, the agricultural vinyl chloride resin film according to the present invention can be spread over agricultural and horticultural facilities such as greenhouses and tunnels in the same way as conventional agricultural covering materials and used for cultivating useful plants. can.

[0008]

Effects of the Invention: The method for producing agricultural vinyl chloride resin film according to the present invention involves scattering fine silica powder before winding it into a roll to prevent adhesion without impairing the smoothness and transparency of the film surface. By producing a vinyl chloride resin film, workability is good without having to sprinkle starch powder etc. during secondary processing, so the agricultural utility value of the present invention is great.

[0009]

EXAMPLES The present invention will be explained in detail below based on examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Examples 1 to 5, Comparative Examples 1 to 8 Polyvinyl chloride (degree of polymerization = 1300)
100 parts by weight dioctyl phthalate
As shown in Table 1 Tricresyl phosphate
5 parts by weight epoxy resin

2 parts by weight Ba-Zn liquid stabilizer
2 parts by weight
Ba-Zn powder stabilizer
Raw materials and resin additives consisting of 1 part by weight and 1.5 parts by weight of sorbitan monopalmitate were weighed. These were stirred and mixed in a super mixer for 10 minutes, then kneaded on a roll heated to 165°C, and a transparent flexible polyvinyl chloride film with a width of 100 cm and a thickness of 0.05 mm was produced using an L-shaped calender. .

[0010] After coming out of the calender roll, the film is brought into contact with a cooling roll to bring the film temperature to 40°C.
Cooled below ℃. One side of this film was sprayed with the first spray using a drum-type fine powder spray machine (nicker spray machine).
For the various fine powders shown in the table, the amount of adhesion was 0.7g/
It was adjusted and sprayed so that the amount was 2 m2. (However, it was not sprayed in Comparative Example 8.) 1 wound into a roll
Three types of films were left in a roll for two weeks in an atmosphere with a temperature of 40°C and a relative humidity of 90%, and then the adhesiveness, surface smoothness, and transparency after washing were evaluated using the following methods. did.

The results are shown in Table 1. Cut a 50cm square film from the adhesive roll, fold it in four, stack it on top of each other, apply a load of 30kg on top of it, and fold it into four pieces.
The film was left in an atmosphere maintained at 0° C. for 24 hours, a load was removed, and the state of adhesion between the film surfaces was observed when the film was loosened. The evaluation results shown in Table 1 have the following meanings.

○ Almost no tackiness △ Slight tackiness ×
The film was extremely sticky and after evaluating the surface smoothness, the film was washed with water and the surface of the film was observed with the naked eye. The evaluation results shown in Table 1 have the following meanings.

○ The surface is extremely smooth △ Some unevenness is observed on the surface × Considerable unevenness is observed on the surface After running water, a 50 cm square film was cut from the transparent roll and kept at 50°C. The film was placed on the top of a water tank containing warm water and then sealed at a 45 degree angle. Both sides were treated for 6 hours, and the transparency of the film after drying was visually determined. The evaluation results shown in Table 1 have the following meanings.

○ Good transparency △
Transparency is slightly inferior ×
less transparent

[0015]

[Table 1]

Claims (1)

[Claims] [Claim 1] Per 100 parts by weight of vinyl chloride resin,
A resin composition containing 30 to 100 parts by weight of a plasticizer is formed into a film, and before this film is wound into a roll, at least one side of the film is coated with a powder having an average particle size of 1 to 5 μm and an apparent specific volume of 1 ml/g or more. Sprinkle fine silica powder,
A method for producing an agricultural vinyl chloride resin film with improved adhesiveness.