JPS6214178B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a low toxicity agricultural vinyl chloride film. More specifically, the present invention relates to a low-toxic agricultural vinyl chloride film that has excellent weather resistance and dust resistance. PVC resin has excellent processability and is inexpensive, so it is widely used in films, sheets, pipes, and other molded products. However, it has low stability against heat and light, and to improve these, cadmium is usually added. Stabilizers such as lead compounds were included along with so-called stabilizing aids such as epoxy compounds, phosphites, antioxidants, and UV absorbers. Among the many known stabilizers, lead compounds and cadmium compounds are particularly effective as stabilizers and have excellent thermal stability and transparency, so even if the product is stored for a long period of time, it may cause bleed (on the surface of the molded product). It is widely used in the production of vinyl chloride resin products due to its low occurrence of liquid substance discharge (a phenomenon in which liquid substances are discharged) and bloom (a phenomenon in which powder substances are discharged onto the surface of a molded product), as well as good weather resistance and dust resistance. However, in recent years, the toxicity of heavy metals such as cadmium has become a problem in terms of occupational safety and health and environmental pollution, and there has been an urgent need to develop so-called low-toxicity resin compositions that do not use cadmium. Low toxicity stabilizers that can replace cadmium compounds include compounds of zinc, alkali metals, and alkaline earth metals, and these are used alone or in combination of two or more. Among these, it is known that the combined use of zinc-calcium organic acid salts, zinc-barium organic acid salts, etc. using organic zinc compounds is preferable. However, although organozinc compounds exhibit almost the same properties as cadmium compounds, they have the drawback of causing the so-called zinc burning phenomenon.To solve this problem, epoxy compounds such as epoxy resins and epoxidized soybean oil are usually used as stabilizing aids. It is being used in combination as Since so-called epoxy plasticizers such as epoxidized soybean oil have problems with bleeding, etc., epoxy resins with relatively few problems such as bleeding are preferably used. However, when used in combination with an epoxy resin, there is a drawback that, although no abnormalities are observed immediately after the film is manufactured, numerous spots, so-called "bumps", appear in the product over time. This problem of "bumps" generation can be solved by the combined use of organic tin compounds (Japanese Patent Publication No. 55-45095) or the combined use of phosphonic acid diesters having at least one aralkyl group (Japanese Patent Publication No. 56-43059).
However, when zinc compounds were used, the problem remained that weather resistance and dust resistance were inferior to those using conventional cadmium compounds. In recent years, farmers have been trying to save on covering materials.
Agricultural covering materials have been used for a long period of time, and weather resistance and dustproof properties are also required more than ever. In view of the current situation, the present inventors have conducted intensive studies on low-toxic agricultural vinyl chloride films with excellent weather resistance and dustproof properties, and have found that they have developed a low-toxic vinyl chloride composition containing an organic zinc compound, which has an additional special epoxy group. The present invention was completed based on the discovery that weather resistance and dust resistance can be significantly improved by adding a specific amount of a siloxane compound having the following as a stabilizing aid. That is, in the present invention, based on 100 parts by weight of vinyl chloride resin, (1) 0.3 to 3.0 parts by weight of an organic acid zinc salt, (2) a total of 0.1 to 2.0 parts by weight of an organic acid alkaline earth metal salt and/or an organic tin compound, (3) 0.1 to 10 parts by weight of epoxy resin, (4) 0.1 to 1.5 parts by weight of lubricant, and (5) siloxane polyoxyalkylene represented by the following general formula.
This is a low-toxic agricultural vinyl chloride film with excellent weather resistance and dust resistance, which is characterized by containing 0.01 to 3.0 parts by weight of an epoxy compound. (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are an alkyl group, X and Y are each independently an alkylene group,
POA is a polyoxyalkylene group, x,
y and z are each independently positive integers of 1 or more. ) The vinyl chloride resin used in the present invention includes not only vinyl chloride homopolymers, but also vinyl monomers copolymerizable with vinyl chloride, such as vinyl acetate,
Copolymers with acrylic acid and its esters, methacrylic acid and its esters, maleic acid, fumaric acid, etc., and mixtures thereof can also be used. The organic acid components of the organic acid zinc salt and organic acid alkaline earth metal salt used in the present invention include organic carboxylic acids such as lauric acid, palmitic acid, stearic acid, oleic acid, and benzoic acid, phenol, dimethylphenol, t -There are phenols such as butylphenol. Further, any alkaline earth metal salt can be used, but particularly preferred are barium, calcium and magnesium salts, which may be used alone or in combination of two or more. Examples of the organic tin compound used in the present invention include tin salts of the organic acids mentioned above, and tetravalent tin compounds such as dibutyltin dilaurate, dioctyltin dimalate, and dibutyltin dilauryl mercaptide. The amount of organic zinc compound added is 100% of vinyl chloride resin.
It is preferably 0.3 to 3.0 parts by weight; if it is less than 0.3 parts by weight, no stabilizing effect can be obtained, and if it is used in excess of 3.0 parts by weight, the transparency of the film will deteriorate. Further, although it is sufficiently effective that either one of the organic acid alkaline earth metal salt and the organic tin compound is blended, it is desirable that both of them are blended because the stabilizing effect will be higher. The total amount of these compounds added is preferably 0.1 to 2.0 parts by weight per 100 parts by weight of vinyl chloride resin. If the amount of these compounds added is less than 0.1 part by weight, no stabilizing effect can be obtained. Furthermore, if more than 2.0 parts by weight is used, the transparency of the film will deteriorate. Examples of the epoxy resin used in the present invention include 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane,
Bis such as 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)butane, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ether, etc. Any so-called epoxy compound obtained by reacting epichlorohydrin with a polyhydric phenol compound such as phenols, their isomers and derivatives, and low molecular weight phenolic resins can be used. The amount of epoxy resin added is vinyl chloride resin.
0.1 to 10 parts by weight per 100 parts by weight, preferably 0.5 to 10 parts by weight
It is 5 parts by weight. If the amount is less than 0.1 part by weight, no effect as a stabilizing agent can be obtained. Further, even if more than 10 parts by weight is used, the same level of stabilizing effect as in the case of less than 10 parts by weight cannot be obtained. The lubricants used in the present invention include hydrocarbon-based lubricants such as micro wax and polyethylene wax, fatty acid-based lubricants such as stearic acid, fatty acid amide-based lubricants such as ethylene bisstearamide and methylene bis-stearamide, and ester-based lubricants. lubricant,
Examples include alcohol-based lubricants. These may be used alone or in combination of two or more. The amount of lubricant added is per 100 parts by weight of vinyl chloride resin.
0.1 to 1.5 parts by weight is preferred. If it is less than 0.1 part by weight, the lubricity during molding will be poor, and if it exceeds 1.5 parts by weight, there will be large blooming on the film surface, resulting in a decrease in dustproofness and weather resistance. The siloxane polyoxyalkylene epoxy compound used in the present invention has the general formula (In the formula, R ¹ to R ⁶ , X, Y, POA, x, y, and z are the same as above.) Any compound represented by the formula can be used. Among them, R ¹ in the above formula () is particularly preferable.
〜R ⁶ are all methyl groups, X and Y are alkylene groups having 1 to 5 carbon atoms, POA is an oxyalkylene group to which at least 4 oxyethylene or oxypropylene are bonded, x, y is 2
-6, and z is 1-3, siloxane polyoxyalkylene epoxy compounds can be mentioned. The amount of siloxane, polyoxyalkylene, and epoxy compound added is per 100 parts by weight of vinyl chloride resin.
0.01 to 3.0 parts by weight, preferably 0.5 to 1.5 parts by weight are suitable. If less than 0.01 parts by weight is added, the weather resistance cannot be improved by adding the siloxane/polyoxyalkylene/epoxy compound. In addition, if the amount exceeds 3.0 parts by weight, the amount of siloxane, polyoxyalkylene, or epoxy compound that bleeds or blooms from the film increases, and the heat sealability of the films decreases.
In addition, this also results in a decrease in dust resistance. Although the low toxicity agricultural film of the present invention does not necessarily require the addition of a water drop preventive agent, it is preferable to add a water drop preventive agent because droplet flow properties can be obtained. Any so-called surfactant can be used as a water droplet prevention agent, but depending on the compatibility with the resin, the degree of flowability obtained, and its sustainability, sorbitan, glycerin, inositol, etc.
Preferred are partial fatty acid esters of polyhydric alcohols such as sugars and their adducts with ethylene oxide or propylene oxide, siloxane surfactants, fluorine-containing surfactants, and the like. Of course, any other surfactant can be used as long as it can be used as a water droplet preventive agent. The amount of the water drop preventing agent added is determined depending on the necessity of the water drop preventing effect, but in the present invention, the appropriate amount is 0 to 3.0 parts by weight per 100 parts by weight of the vinyl chloride resin. The low-toxic agricultural vinyl chloride film of the present invention is produced by adding the above-mentioned various additives to vinyl chloride resin, and further adding known plasticizers such as phthalate esters, adipate esters, fatty acid esters, phosphate esters, and epoxy plasticizers. Per 100 parts by weight of vinyl chloride resin
It is produced by adding 20 to 70 parts by weight, kneading, and then molding by a known method such as a calendar method or an extrusion method. The low toxicity agricultural vinyl chloride film of the present invention may contain triphenyl phosphorite,
Phosphite esters such as tribenzyl phosphite and monoalkyl diphenyl phosphite, epoxy compounds such as epoxidized soybean oil, antioxidants, stabilizing aids such as ultraviolet absorbers, antistatic agents,
Of course, colorants, pigments, fillers, blowing agents, antifungal agents, plate-out inhibitors, and the like may be added. In addition, the low-toxic agricultural vinyl chloride film of the present invention itself has good dust-proof properties, but it becomes even better when a layer of dust-proof resin such as acrylic resin, silicone resin, or fluorine resin is provided on its surface. This is preferable because it improves dust resistance. The low-toxic agricultural vinyl chloride film of the present invention has excellent dust resistance and weather resistance, so it can be used for a long period of time and is excellent as a covering material for greenhouses. Furthermore, when the low-toxicity agricultural vinyl chloride film of the present invention is used for covering greenhouses, it is good in that there are almost no "holes" that conventionally occur inside greenhouses. The present invention will be explained below with reference to Examples. Examples 1 to 12 and Comparative Examples 1 to 6 Vinyl chloride resin Vinicron 4000M-3 (trademark,
100 parts by weight (manufactured by Mitsui Toatsu Chemical Co., Ltd.), 45 parts by weight of dioctyl phthalate, 5 parts by weight of tricresyl phosphate, 2.0 parts by weight of epoxy resin Epicoat 828 (trademark, manufactured by Yuka Shell Co., Ltd.), and triphenyl phosphite.
1.0 parts by weight of stabilizers, lubricants, anti-drop agents, siloxane, polyoxyalkylene, etc. listed in Table 1.
Epoxy compound (EPG manufactured by Toray Silicone Co., Ltd.)
-1) was added in the amount listed in Table 1, mixed uniformly with a Henschel mixer, kneaded for 10 minutes with an open roll set at 180°C, and then mixed using a 30-inch Z-type calender set at 180°C. A 0.1 mm agricultural vinyl chloride film was created. The films obtained above were spread in pipe houses each having a width of 4.5 m and a depth of 40 m from late October, and a two-year extension test was conducted to evaluate the quality (weather resistance and dust resistance) of each film. The results are shown in Table 1. During this expansion test, tomatoes, cucumbers, and other vegetables were cultivated year-round in the greenhouse, and normal irrigation, ventilation, and harvesting were performed. Furthermore, weather resistance and dust resistance were evaluated as follows. [Weather resistance] Using an Instron type tensile tester, the elongation at break (%) measured at a tensile speed of 300 mm/min was calculated as the ratio (elongation retention at break, %) to the value of the film before stretching. . The larger this ratio is, the better the weather resistance is. [Dustproofness] The state of dust adhesion to the outer surface of the film was visually determined. The evaluation is as follows. A: Almost none B: Somewhat C: Somewhat much D: Many E: Quite a lot F: Significant

【table】

[Table] Examples 13 to 20 and Comparative Examples 7 to 11 Vinyl chloride resin “Vinicron 4000M-3” 100
Parts by weight, 45 parts by weight of dioctyl phthalate, 4 parts by weight of tricylyl phosphate, epoxy resin "Epicoat"
828”1.5 parts by weight, 2.0 parts by weight of epoxidized soybean oil,
0.5 parts by weight of triphenyl phosphonate, 0.5 parts by weight of dibenzylphosphonate, 1.0 parts by weight of sorbitan monopalmitate, and fluorine-containing surfactant "Megafauc 142D" (trademark, Dainippon Ink Co., Ltd.)
The stabilizer, lubricant, and siloxane polyoxyalkylene epoxy compound "EPG-1" listed in Table 2 were added to 0.5 part by weight of the product (manufactured by M.D.) in the amount shown in Table 2, and the procedure was repeated in the same manner as in Example 1. An agricultural vinyl chloride film with a thickness of 0.1 mm was obtained. The quality of this film was evaluated in the same manner as in Example 1. The results are shown in Table 2.

【table】

[Table] As shown in Tables 1 and 2, the low-toxic agricultural vinyl chloride film of the present invention containing siloxane, polyoxyalkylene, and epoxy compounds has weather resistance equivalent to that containing cadmium stabilizers. It also has somewhat excellent dustproof properties. In addition, the material of the present invention has improved weather resistance and dust resistance compared to products to which no siloxane, polyoxyalkylene, or epoxy compound is added.

Claims (1)

[Claims] 1. Total amount of (1) organic acid zinc salt 0.3 to 3.0 parts by weight, (2) organic acid alkaline earth metal salt and/or organic tin compound 0.1 to 2.0 parts by weight per 100 parts by weight of vinyl chloride resin.
Parts by weight, (3) 0.1 to 10 parts by weight of epoxy resin, (4) Lubricant
A low-toxic agricultural product with excellent weather resistance and dust resistance, characterized by containing 0.1 to 1.5 parts by weight and (5) 0.01 to 3.0 parts of a siloxane polyoxyalkylene epoxy compound represented by the following general formula (). vinyl chloride film (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are an alkyl group, X and Y are each independently an alkylene group,
POA is a polyoxyalkylene group, x,
y and z are each independently positive integers of 1 or more. )