JPH01210448A - Agricultural vinyl chloride resin film - Google Patents

Abstract

PURPOSE:To obtain the title film improved in nonstickiness, heat insulating property and transparency, by adding inert fine solid particles of a specified weight/particle size distribution to a vinyl chloride resin and forming the obtained mixture into a film. CONSTITUTION:100 pts.wt. vinyl chloride resin is mixed with 5-20 pts.wt. inert fine solid particles containing 0.5-2 pts.wt. particles of a particle diameter >=2mum having such a weight/particle size distribution that maximum peaks (h1) and (h2) exist in particle size ranges of 2-20mum and below 2mum, and the ratio hmin/h3 (wherein hmin is the height of the lower one of them and h3 is the lowest height in the valley formed between both peaks is at least 1.2) and having an absorption in an infrared region of a wavelength of 4-25mum and, optionally, a plasticizer, an antifogging agent, etc. The obtained mixture is formed into a film, and this film is drawn uniaxially or biaxially at 130-200 deg.C in an areal ratio <=20 to obtain an agricultural vinyl chloride resin film of a thickness of 0.03-0.5mm.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to an agricultural vinyl chloride Mtjf fat film that has non-stick properties, heat retention properties and transparency.

"Prior Art" In recent years, in order to efficiently cultivate useful plants, accelerated cultivation in greenhouses or tunnels has become widely adopted. A vinyl chloride resin film is often used as a material for covering the house or tunnel because of its excellent weather resistance, transparency, heat retention, strength, etc.

Vinyl chloride P and resin films usually have a plasticizer added to them, so they are soft and elastic, and have the advantage of being easily stretched into any shape of house or tunnel. However, this film has the disadvantage that it is highly adhesive, which reduces the efficiency of spreading it into the house or tunnel, and after spreading, the efficiency of ventilation work and opening/closing work in the house or tunnel is low. In order to improve the adhesion of adhesives, which have the drawback of reducing the work efficiency of adhering them together using high-frequency adhesion, polyethylene wax, fatty acid alkaline earth metal salts, amide compounds, or inorganic solid particles are used. Although they are added to prevent adhesion, polyethylene wax, alkaline earth metal salts of fatty acids, amide compounds, etc. bleed out onto the surface of the film and impair the transparency of the film either by themselves or due to the adhesion of dust. However, since a large amount of inorganic solid particles having a considerably large particle size are added, there is a problem that the strength of the film decreases.

Recently, in order to improve the heat retention properties of agricultural films, a method of adding inorganic fine powder has been proposed, for example, in
Although it is disclosed in Publication No. 164238 or Japanese Patent Publication No. 32-10124, there are variations in the 1-heat effect during adhesion, and the transparency is also not constant. It was difficult to obtain a film with high transparency.

[Problems to be Solved by the Invention] The present inventors have conducted various studies with the aim of obtaining a well-balanced agricultural film with excellent heat retention, non-adhesiveness, and transparency. If it is an inert solid fine particle that has a weight particle size distribution with two peaks in the range of 2-ulOμ and less than 2μ, if a considerable amount of it is included in an agricultural film, even a small amount of particle size of 2μ or more can be achieved. The present inventors have discovered that it is possible to obtain a film that exhibits good non-adhesive properties and also has heat retaining properties and transparency, and has completed the present invention.

That is, an object of the present invention is to provide an agricultural vinyl chloride resin film that has excellent non-adhesive properties, heat retention properties, and transparency.

[Means for Solving the Problems, 1] However, the gist of the present invention is that inert solid fine particles having absorption in the infrared a region of wavelength 4 and 25μ are blended into vinyl chloride resin. In the agricultural vinyl chloride resin film, the inert solid fine particles exhibit maximum peak heights (hl) and (b2) in a particle size range of 2-=, 10μ and less than 2μ, respectively, and Height of the lower of both peaks (1+, 3)
and the lowest height of the valley consisting of the opening θ of both peaks (11
! > has a weight particle size distribution in which the ratio h − / h s is 1.2 or more, and the inert solid fine particles are
Per 100 parts by weight of S resin, particles with a particle size of 2μ or more are used.
The agricultural vinyl chloride resin film is characterized in that it contains 5 to 2 parts by weight and is blended in a total amount of 6 to 20 parts by weight.

The present invention will be explained in detail below.

In the present invention, the vinyl chloride resin includes polyvinyl chloride, a copolymer mainly composed of vinyl chloride with other comonomers, a mixture thereof, or a mixture of these with other polymers or copolymers.

In addition, inert solid particles that absorb in the infrared range of wavelengths from 4 to 25μ include magnesium carbonate, magnesium silicate (talc), silicon oxide, aluminum oxide, barium sulfate, calcium sulfate, magnesium hydroxide, and water. Aluminum oxide, calcium hydroxide, metal phosphates, hydrotalcites (hydrous or anhydrous aluminum/magnesium basic carbonates, sulfates, nitrates, phosphates; aluminum/zinc basic carbonates, sulfates,
Among these, aluminum hydroxide, magnesium hydroxide, talc, silicon oxide, magnesium carbonate, and hydrotalcinate are particularly preferred because they cause less deterioration in the transparency of the film.

The inert solid fine particles contained in the agricultural vinyl chloride resin of the present invention have a maximum peak (b
3) and the maximum peak (b2) in the range of less than 2μ, and the height of the former maximum peak (b3) and the height of the latter maximum peak. The ratio of h1/l+a is between the height (b,, 3) of the lower peak of the height (+12) and the lowest height (1+3) of the valley formed between both peaks. It is required that the value is 1.2 or more. That is, it is necessary to have a two-peak particle size distribution having peaks in the ranges of at least 2 to 10 microns and less than 2 microns, respectively.

The inert solid fine particles having a bimodal particle size distribution may be made of one type of compound, but it is difficult to adjust the particle size distribution during the manufacture of the fine particles, and the absorption wavelength in the infrared region is narrow9. However, the average particle size is usually 2
rv49 (manufactured by Rv49) was prepared by mixing two or more types of inert solid fine particles having a particle size of ~10μ and inert solid fine particles having an average particle size of less than 2μ so as to have maximum peaks in the particle size ranges of 2-ulOμ and less than 2μ, respectively. ) is preferable.

In the present invention, it is necessary to contain 6 to 20 parts by weight of the above-mentioned inert solid fine particles to 100 parts by weight of the vinyl chloride resin, and the inert solid fine particles with an internal particle size of 2" (710 μm) are required. It is necessary that the content of inert solid fine particles is less than 6 parts by weight, the effect of improving heat retention is insufficient; If the content is less than 0.5 parts by weight, the transparency of the film will be impaired.In addition, if the content of inert solid fine particles with a particle size of 2 to 10 μm is less than 0.5 parts by weight, the non-adhesive effect will be insufficient. On the other hand, if the amount exceeds 2 parts by weight, the surface of the film tends to become rougher than necessary, and at the same time, the transparency of the film tends to be impaired. Even if the addition ratio to the vinyl chloride resin is in the range of 6 to 20 parts by weight, the maximum peak of inert solid fine particles (111)
The effect of the present invention is more easily exhibited when the particle size distribution and the maximum peak (11□) are separated in the particle size distribution.

The agricultural vinyl chloride i-resin film of the present invention usually contains a plasticizer and is used as a soft film. As a plasticizer, for example, di-n-octyl 7-talate, di-n-octyl 7-thaletate,
Heptatalytic acid esters such as ethylhexyl heptatarate, didodecyl heptatarate, diisodecyl heptatarate, didodecyl heptatarate, didodecyl heptatarate, isophthalic acid esters such as diisooctyl heptatarate, c-n-butyl annovate, Fatty acid esters such as dioctyl adipate, maleic esters such as non-n-butyl maleate,
Citric acid esters such as tri-11-butyl citrate, itaconic esters such as monobutyl itafnate,
Various plasticizers include oleic acid esters such as butyl oleate, ricinoleic esters such as glyceryl monolysyllate, other phosphate esters such as tricresyl phosphatide, and epoxy-based plasticizers such as epoxidized soybean oil and epoxy resin. used in or in combination. The appropriate blending ratio for the vinyl chloride resin is 30 to 60 parts by weight per 100 parts by weight of the vinyl chloride resin.

The agricultural vinyl chloride resin film of the present invention may contain additives usually added to vinyl chloride resins, such as antifogging agents, antifog agents, lubricants, heat stabilizers, antistatic agents, and ultraviolet absorbers, as necessary. It may also contain additives and colorants.

The agricultural vinyl chloride of the present invention [fat film is prepared by adding and blending inert solid fine particles, a plasticizer, and various additives as necessary to a vinyl chloride resin, and then using a known method, for example,
6 Agricultural vinyl chloride resin film, which can be manufactured by various molding methods such as melt extrusion method, calendar molding method, and melt flow method, has a manufacturing cost of 130, \, 200 during molding.
It is desirable that the film be stretched at a temperature of 20 times or less, preferably about 1.5 to 10 times, in one or two axial directions.

At this time, the inert solid fine particles are partially exposed on the film surface, and the non-adhesive effect of the film can be improved. In addition, the thickness of the film is 0.03 to 0,5+eu+, preferably 0.
．． It is best to keep it in the range of 0.05 to 0.3.

"Effects of the Invention" The agricultural vinyl chloride resin film of the present invention has wavelengths of 4 to 4.
It shows absorption in the infrared region in the range of 25μ, and has a particle size of 2 to 10
Contains inert solid fine particles having maximum peaks in the μ range and in the range of less than 2 μ, and contains a small amount of fine particles with a particle size of 2 to 10 μ, resulting in three effects: heat retention, transparency, and non-adhesion. It also has excellent strength because it does not contain large particle size solids, making it extremely useful as an agricultural covering material.

"Examples" Next, the present invention will be described in detail based on Examples, but the present invention is not limited to the following Examples unless it departs from the gist thereof.

Example 1'6, Comparative Example 1 713 After stirring and mixing the following blended composition with a super mixer,
The mixture was mixed on a roll heated to 170°C, and an agricultural vinyl chloride resin film having a thickness of 0.075 mm was produced using a calendar roll at the same temperature. The film is stretched to an area ratio of 6 times in the vertical direction between a calendar roll and a winding surface.

Vinyl chloride resin (average degree of polymerization 1400) 100 parts by weight di-2-ethylhexyl 7-talate 45 Tricresyl phosphate 5 Epoxy resin plasticizer (stabilizer, trade name: Pico) 828) 1 // Barium-zinc composite Liquid stabilizer 1 Barium stearate 0.2 Zinc stearate
0.4 〃Ethylene bisstearamide)'
0.3/l sorbitan monostearate 2
．． 0 〃Inert solid fine particles (shown in Table 1) Predetermined excess weight part The quality of the film thus obtained was evaluated,
The results are shown in Table 1.

The quality evaluation method is as follows.

(1) Two films with an adhesiveness of 30<em>X 1001 were stacked and pressed together with rubber rolls to eliminate air in the opening of the film, and the two films were brought into close contact with each other. Placed in the oven set and held at this temperature for 2 hours.

The film is then removed from the oven and left at room temperature for 15 minutes.
After standing for a minute, the two films were peeled off using a tensile tester, and the peel stress at that time was measured. The unit of peeling stress was the number of grams required to peel 30 wheel widths.

(2) Heat retention In a field in Shigun, Mie Prefecture, open tunnels with two wheels in diameter and two wheels in length were installed, and each tunnel was covered with a film.
The temperature inside the tunnel at night was measured at the center of the tunnel.

The measurement period was from November 16, 1988 to November 2, 1988.
For 10 days up to the 5th, the temperature was measured every hour from 6:00 pm to 6:00 am the next day, and this darkness temperature was averaged to obtain the daily average value, and then the average value for the 10 days was calculated. Shown as temperature.

(3) Transparency For each sample film, the straight light transmittance at a wavelength of 555 nI11 was measured using a model 323 spectrophotometer manufactured by Hitachi Seisakusho. This straight light transmittance means that the closer the value is to 90% of a film that does not contain inert solid particles, the more transparent the film is.

＼ ＼ As is clear from Table 1, the agricultural vinyl chloride resin film of the present invention has a transparency of 80% or more, and compared to the film without the addition of inert solid particles (Comparative Example 13), Yuryu has a small decrease in transparency, and also has excellent heat retention and non-adhesive properties.
It has three effects. On the other hand, in comparative examples in which the particle size and blending amount of the inert solid fine particles are different, or in which the ratio in the particle size distribution is outside the specifications of the present invention, at least one of the performances of non-adhesion, heat retention, and transparency is achieved. Inferior.

In addition, magnesium carbonate (Comparative Examples 8 and 9) and talc (Comparative Examples 10 and 11) showed only one peak,
There was no two-mountain distribution.

Patent applicant: Mitsubishi Kasei Vinyl Co., Ltd. Representative patent attorney for long diameter - (1 idiot)

Claims (1)

[Claims] (1) In an agricultural vinyl chloride resin film in which inert solid fine particles having absorption in the infrared region in the wavelength range of 4 to 25 μm are blended to a vinyl chloride resin, the inert solid fine particles have a particle size of 2 to 10 μm. maximum peak heights (h_1) and (h_2) in the range of The ratio between the lowest height (h_3) h_m_i_n/
The inert solid particles have a weight particle size distribution in which h_3 is 1.2 or more, and the inert solid particles are mixed into 2 parts per 100 parts by weight of vinyl chloride resin.
An agricultural vinyl chloride resin film, characterized in that it contains 0.5 to 2 parts by weight of particles having a particle size of μ or more, and is blended so that the total amount is 6 to 20 parts by weight.