JPH04126747A - Vinyl chloride resin film for agricultural use - Google Patents

Abstract

PURPOSE:To obtain the subject film effective in suppressing the bleed-out of ultraviolet absorber, usable over a long period with little lowering of transparency and capable of transmitting sufficient sunlight by compounding an ultraviolet absorber and magnesium hydroxide, etc., to a base film. CONSTITUTION:The objective film is produced by compounding (A) an ultraviolet absorber of an amount effective to essentially inhibit the transmission of ultraviolet ray having wavelength shorter than 380nm [preferably a benzotriazole-type ultraviolet absorber of formula I (R<1> is 3-5C branched alkyl; R<2> is 1-8C alkyl)] and (B) magnesium hydroxide and/or a hydrotalcite of formula II (0<x<0.5; 0<=m<=2) (e.g. the compound of formula III). The amount of the ultraviolet absorber is preferably 1.0-5 pts.wt. per 100 pts.wt. of vinyl chloride resin.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a vinyl chloride resin film for agricultural use. More specifically, the present invention relates to an agricultural vinyl chloride resin film with excellent transparency that substantially blocks light of 380 r+m or less and prevents bleeding out of ultraviolet absorbers over a long period of time.

"Prior Art" In recent years, in order to efficiently cultivate useful plants, accelerated cultivation in greenhouses or tunnels has become popular. 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.

Furthermore, it has been known for a long time that by blocking ultraviolet rays, the occurrence of plant pathogens such as gray mold and sclerotium, as well as pests such as southern thrips and aphids, has been suppressed. No., Japanese Patent Publication No. 52
-117738, JP-A-51-2238, JP-A-5
This method has been proposed in No. 3-12942, Japanese Unexamined Patent Publication No. 53-27539, etc.

However, in order to substantially block UV radiation, it is necessary to add a significant amount of UV absorber. When cultivating useful plants by spreading such a vinyl chloride resin film in a greenhouse, tunnel, etc., there is a drawback that the ingredients, especially the ultraviolet absorber, bleed out over time, impairing transparency. This bleed-out phenomenon occurs particularly frequently during low-temperature seasons, so in winter when the amount of solar radiation is low, the bleed-out phenomenon reduces transparency and hinders plant growth.

As a technology that improved these drawbacks,
As described in Publication No. 8143, one or both sides of an ultraviolet-shielding polyvinyl chloride resin film,
A method of applying a coating made of an acrylic polymer has been proposed.

``Problems to be Solved by the Invention'' However, in low-temperature periods, the acrylic polymer bleeds out within a few days after film processing, so it is necessary to apply the acrylic polymer quickly during film processing. If the inside of the greenhouse remains dry even if it is spread in a greenhouse, etc.,
There is a disadvantage that the bleed-out phenomenon cannot be suppressed.

``Means for Solving the Problems'' Under such circumstances, the present inventors have devised a simple method for producing agricultural chloride that can easily prevent bleed-out over a long period of time without being affected by environmental conditions, and has excellent transparency. As a result of intensive studies aimed at providing a vinyl resin film, we found that even when a large amount of ultraviolet absorber is blended, transparency can be maintained for a long period of time by combining magnesium hydroxide and/or hydrotalcites. This is what led them to complete the present invention.

Therefore, the gist of the present invention is that an ultraviolet absorber is blended in an amount that substantially blocks the transmission of ultraviolet rays having a wavelength of 380 nm or less, and magnesila hydroxide and/or hydrotalcites are blended. This is an agricultural vinyl chloride resin film.

The present invention will be explained in detail below.

In the present invention, the 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 with other polymers or copolymers.

In the present invention, 'substantially blocking the transmission of ultraviolet light with a wavelength of 380 nm or less' means not only completely blocking 100% of ultraviolet light with a wavelength of 380 nm or less, but also blocking the transmission of ultraviolet light with a wavelength of 2%.
It is used to mean that the following is allowed.

The amount of the ultraviolet absorber added to the vinyl chloride resin varies depending on the ultraviolet absorption performance of the ultraviolet absorber used and the film thickness, but is 1.0 to 5 parts by weight per 100 parts by weight of the vinyl chloride resin. It can be a range of parts by weight.

Examples of the ultraviolet absorbent in the present invention include benzotriazole-based, hesiphenone-based, salicylic acid-based, and cyanoacrylate-based ultraviolet absorbers that are commonly used in agricultural vinyl chloride resin films.

In particular, benzotriazole-based ultraviolet absorbers represented by the following formula are preferred because they have strong ultraviolet absorbing ability when used in a relatively small amount.

(In the formula, R1 represents a branched alkyl group having 3 to 5 carbon atoms, and R2 represents a linear or branched alkyl group having 1 to 8 carbon atoms.) Especially, Hensitriazole ultraviolet absorbers represented by the following formulas (3) and (4) are preferred.

In the present invention, magnesium hydroxide and/or hydrotalcites are further blended, and the blending amount is in the range of 0.5 to 10 parts by weight.As hydrotalcite a, the following formula 84 (T ) is used.

Mg+-x Alx (OH)z(C(h)xzz
' 1lHzO(T) (however, O<x<0.5
．． 0sm≦2) Specifically, the following can be mentioned.

Mgo, 1JIo, 3s(OH)z(CO3)o, +a
s ・0.5HzO1Mgo, 6? A.I. , sz
(O)I) z (CO3). , 86.・0.3
Lo, Mgo, 6Jlo, 1z(OH)z(Cogo).

, +isMgo, Jl. , s (OH) 2 (CO
s). , 1.・0.5uto, Mgo, Jlo, x(O
H)z(COz). 1.・0.3H2O2Mgo, Jl
. , 5(OH)z(CO*). ,,.

The vinyl chloride resin base material constituting the agricultural vinyl chloride resin film according to the present invention may contain various usual resin additives, such as plasticizers, lubricants, heat stabilizers, light stabilizers, oxidation Preservatives, surfactants, pigments, dyes, etc. can be included in conventional amounts.

For example, regarding the soft vinyl chloride resin suitable for the present invention, the plasticizer is added in an amount of about 30 to 70 parts by weight based on 100 parts by weight of the polyvinyl chloride resin base material having a degree of polymerization of about 1000 to 2000. Can be blended. Suitable plasticizers that can be used include, for example, phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, didodecyl phthalate, and diisodecyl phthalate; Isophthalic acid derivatives; adipic acid derivatives such as di-n-butyl adipate and dioctyl adipate; maleic acid derivatives such as di-n-butyl maleate; citric acid derivatives such as tri-n-butyl citrate; itaconic acid such as monobutyl itaconate Derivatives; Oleic acid derivatives such as butyl oleate; Ricinoleic acid derivatives such as glycerin monolysyllate; Other examples include tricresyl phosphate, epoxidized soybean oil, and epoxy resin plasticizers.

Examples of the surfactant include nonionic surfactants such as sorbitan surfactants and glycerin surfactants, and fluorine surfactants.

These resin additives may be contained in a small amount of 10 parts by weight or less per 100 parts by weight of the vinyl chloride resin base material.

In order to blend the UV absorber, magnesium hydroxide and/or hydrotalcite 1%, and various resin additives if necessary, into the base vinyl chloride resin, conventional blending techniques and mixing techniques such as ribbons are used. It can be mixed using a blender, Banbury mixer, super mixer, or other blender/mixer.

In order to form a film from a vinyl chloride resin, a method known per se, such as a melt extrusion method, a solution casting method, a calender method, etc., may be employed.

If the thickness of the agricultural vinyl chloride resin film according to the present invention is too thin, the strength will be insufficient, which is undesirable.On the other hand, if it is too thick, it will be difficult to make the film into a film, and the subsequent handling (cutting the film and joining it into a house shape) is not desirable. 0.03 to 0.2 as it causes inconvenience to the work (including the work of expanding the greenhouse), etc.
It is preferable to set it within the range of wm.

Moreover, the agricultural vinyl chloride resin film according to the present invention is
Similar to conventionally used agricultural covering materials, it can be spread over agricultural and horticultural facilities such as greenhouses and tunnels, and used for cultivating useful plants.

"Effect of the invention" l! [The general purpose vinyl chloride resin film is
It has the following remarkable effects, and its industrial value is extremely great.

(1) In the greenhouse or tunnel in which the agricultural vinyl chloride resin film according to the present invention is spread, bleeding out of the ultraviolet absorber is suppressed and remains transparent even after long-term use, as is clear from the examples below. There is little decline in sexuality. Therefore, poor growth of useful plants due to lack of sunlight can be prevented.

Hereinafter, the present invention will be explained in detail based on examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Examples 1 to 4, Comparative Examples 1 to 5 Polyvinyl chloride (degree of polymerization = 1300) 100 parts by weight Dioctyl phthalate 45 Tricresyl phosphite 5 Epoxy resin
2 Ba-Zn liquid stable cutting
2 Ba-Zn powder stabilizer
1 (Sorbitan monopalmitate)] and 5 (Sorbitan monopalmitate) were used as the basic composition, and the ultraviolet absorber and magnesium hydroxide and/or hydrotalcites shown in Table 1 were blended therewith and mixed in a super mixer. 180% of the mixture
The mixture was fed into a calender molding machine heated to 'C and formed into a film by a conventional method to produce 8 types of films with thicknesses of 0 and 1 tttm.

The transparency of the above eight types of films was evaluated using the following method. The results are shown in Table 1.

(1) Evaluation of transparency A pipe house with a width of 5.4 m, a ridge height of 3 m, and a depth of 18 m was constructed in a field in Shigun, Mie Prefecture, and on September 20, 1989, the above eight types of films were applied to each 2 m wide pipe house. It was coated so that

On February 20, 1990, 5 months after the covering, the ground was 1.5 m above ground.
The flat part of the sample was sampled, and the total light transmittance at a wavelength of 555 nm was measured using a spectrophotometer (manufactured by Hitachi, Model 323).

Chapter 1 Table Ultraviolet absorber (A): HOtert-C4H9 CI CH.

Ultraviolet absorber [B]: Hydrotalcites [C]: Mgo, 67Alo, 3:+(OH)z(COi)o,
+i, s '0.5) 1zO hydrotalcites [
D]: Mgo, 6Jlo, 1i(OH)z(CO+). 1
．． .

Patent applicant: Mitsubishi Kasei Vinyl Co., Ltd. Representative Patent Attorney Hase - (1 other person)

Claims (3)

[Claims] (1) Contains an amount of ultraviolet absorber that substantially blocks the transmission of ultraviolet rays with a wavelength of 380 nm or less, and also includes magnesium hydroxide and/or hydrotalcites represented by the following general formula (I) Agricultural vinyl chloride resin film. Mg_1_-_xAl_x(OH)_2(CO_3)_
x_/_2・mH_2O---(I) (However, 0
<x<0.5, 0≦m≦2) (2) The agricultural vinyl chloride resin film according to claim 1, wherein the ultraviolet absorber is a benzotriazole ultraviolet absorber represented by the following general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) (In the formula, R^1 represents a branched alkyl group having 3 to 5 carbon atoms; Represents 8 straight or branched alkyl groups.) (3) The agricultural vinyl chloride resin film according to claim 1, which contains 1.0 to 5 parts by weight of an ultraviolet absorber based on 100 parts by weight of the vinyl chloride resin.