JPS6238378B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to an agricultural vinyl chloride resin film. More specifically, the present invention relates to a soft vinyl chloride resin film for agricultural use that has excellent cold resistance, is resistant to tearing due to creases and scratches, and has excellent weather resistance. "Conventional technology" In recent years, farmers cultivating useful plants have widely adopted methods of promoting or suppressing cultivation of useful plants in greenhouses or tunnels in order to improve profitability. Ta. As the material for covering the house or tunnel, polyethylene film, ethylene-vinyl acetate copolymer film, vinyl chloride resin film, etc. are used. Among them, vinyl chloride resin film has the following characteristics compared to other synthetic resin films:
It has the best overall light transmittance, heat retention, mechanical strength, durability, workability, economic efficiency, etc.
Widely used. However, soft films made of vinyl chloride resins have conventionally been prone to creases and scratches, which has caused the problem of tearing during expansion into a house. In order to spread the film into a greenhouse for cultivating useful plants, we first go to an adhesive processing factory to create a film with a width of 100 cm or more.
A 400cm long film is cut and glued to match the shape and size of the house. The adhesive processed in this way is folded into a kudzu-fold shape,
In some cases, the fruit is squeezed using a squeezing machine into a portable size, stored, and then delivered to farmers. At farms, they are kept folded until they are expanded into greenhouses. Next, unfold the film that was folded during use,
Place it over the house frame and hold it down with binding wire or other holding cords to complete the expansion. Even if the film is soft, creases occur when the film is folded, and when the film is unfolded and placed over the house frame, the creases cause tears. Breakage of the film due to these creases frequently occurs during stretching at low temperatures. On the other hand, the surface of the film placed over the frame of the house may be scratched due to the hanging of the film holding string, ventilation work within the house, etc., and this may cause the film to tear. Film tearing caused by these scratches is also concentrated during low temperature periods. As a measure to prevent the above-mentioned creases, scratches, etc. from occurring in the film, increasing the amount of plasticizer blended has been taken. However, with polyvinyl chloride, which has a degree of polymerization of about 1050 to 1450, which has been conventionally used as agricultural films, increasing the amount of plasticizer added makes the film softer, improves its flexibility during low temperatures, and improves its flexibility during low temperatures. Although it is possible to improve the film so that it does not have creases, it becomes too soft at room temperature, and a new problem arises in that the film surface becomes sticky, so this is not a desirable solution. "Problems to be Solved by the Invention" Under such circumstances, the present inventors have found that the film has excellent cold resistance, is resistant to tearing due to creases and scratches, has a less sticky surface, and has excellent weather resistance. The purpose of the present invention is to provide a flexible vinyl chloride resin film for agricultural use that has excellent properties. "Means for Solving the Problem" The gist of the present invention is to add 100 parts by weight of a vinyl chloride resin with an average degree of polymerization of 1500 to 2500, and (A) 30 to 70 parts by weight of a phthalate ester plasticizer. (B) 1 to 7 parts by weight of a phosphate ester plasticizer, and (C) 0.5 to 7 parts by weight of an epoxidized plasticizer, and formed into a film. Exists. 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 and a vinyl compound that can be copolymerized with the polyvinyl chloride. Examples of vinyl compounds copolymerizable with vinyl chloride include vinyl acetate, ethylene, propylene, vinylidene chloride, acrylic acid and its alkyl esters, methacrylic acid and its alkyl esters, maleic acid, fumaric acid, acrylonitrile, and the like. The above vinyl chloride resin has an average degree of polymerization of 1500~
2500. When the average degree of polymerization is less than 1500,
This is undesirable because the purpose of preventing film tearing caused by analysis wrinkles and scratches is not achieved.
If the average degree of polymerization exceeds 2500, processability will be poor and it will be difficult to form into a film, which is not preferred.
Note that the vinyl chloride resin may be a mixture of two or more types having different average degrees of polymerization. In this case, it is sufficient that the arithmetic mean value taking into account the average degree of polymerization and the proportion of each component is in the range of 1500 to 2500.
All of the average degrees of polymerization of individual vinyl chloride resins are
It does not need to be within the above range. In the film according to the present invention, a phthalate ester plasticizer as the component (A) is blended with the vinyl chloride resin. Examples of phthalate ester plasticizers include dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, diisooctyl phthalate,
Examples include di-2-ethylhexyl phthalate, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, didodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, and butylbenzyl phthalate. These phthalate ester plasticizers, which are component (A), may be blended singly or in combination of two or more, but the blending amount is determined by the base vinyl chloride resin.
The amount shall be selected within the range of 30 to 70 parts by weight per 100 parts by weight. If it is less than 30 parts by weight, the flexibility of the film will be poor and the purpose of preventing the film from tearing due to creases and scratches will not be achieved, which is not preferable. If it exceeds 70 parts by weight, the film becomes too flexible and does not have sufficient strength, which not only makes the film more likely to break due to creases and scratches, but also makes the film surface sticky, causing the film surfaces to stick to each other. This is not desirable because it causes what is called "blocking".
Within the above range, 40 to 60 parts by weight is particularly preferred. In the film according to the present invention, a phosphate ester plasticizer as component (B) is blended with the vinyl chloride resin. Phosphate ester plasticizers include trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tricylenyl phosphate, diphenyl octyl phosphate, diphenyl cresyl phosphate, triethyl phenyl phosphate, etc. can be given. These phosphoric acid ester plasticizers, which are component (B), may be blended singly or in combination of two or more, but the blending amount is determined by the base vinyl chloride resin.
The amount shall be selected within the range of 1 to 7 parts by weight per 100 parts by weight. If the amount is less than 1 part by weight, the weather resistance of the film will not be improved, which is undesirable. If it is more than 7 parts by weight, the cold resistance and workability of forming the film will be poor, and "blocking" will occur, which is not preferred. Within the above range, 1.5 to 6 parts by weight is particularly preferred. In the film according to the present invention, an epoxidized plasticizer as the component (C) is blended with the vinyl chloride resin. Epoxidized plasticizers include epoxidized soybean oil, epoxidized linseed oil, epoxidized fish oil, epoxidized tall oil fatty acid ester, epoxidized medium fat oil, epoxidized polybutadiene, epoxy methyl stearate, epoxy butyl stearate,
2-ethylhexyl epoxy stearate, stearyl epoxy stearate, tris(epoxypropyl) isocyanurate, epoxidized castor oil, epoxidized safflower oil, epoxidized linseed oil fatty acid ester, 3-(2-xenoxy)-
1,2-epoxypropane, bisphenol A.
Examples thereof include diglycidyl ether, vinylcyclohexene diepoxide, and a polycondensate of 2,2-bis(4-hydroxyphenyl)propane and epichlorohydrin. The epoxidized plasticizer, which is the component (C) above, may be blended singly or in combination of two or more types, but the blending amount is 0.5 to 7 parts by weight per 100 parts by weight of the base vinyl chloride resin. The choice shall be made within the range. If it is less than 0.5 parts by weight, the workability of forming a film will be poor and weather resistance will not be improved, which is undesirable. If it is more than 7 parts by weight, cold resistance and film formability will be poor, and "blocking" will occur, so it is not preferred. . Within the above range, 0.5 to 5 parts by weight is particularly preferred. In the film according to the present invention, the three components (A), (B), and (C) are selected within the range of the above blending amounts and are necessarily blended, but the total amount of these three components is The amount shall be selected in the range of 40 to 80 parts by weight per 100 parts by weight of the system resin. If selected within this range, the film will have excellent moldability and weather resistance, and will not cause "blocking".
The film can be made into a film that is resistant to cracking, has excellent cold resistance, and is resistant to tearing due to creases and scratches. When combining the above three components, the ratio of component (A) to component (B) should be 1:1/5 to 1/5 by weight.
It is particularly preferred that the ratio of component (A) to component (C) be 1:1/10 to 1/100 by weight. In addition to the above three components, the agricultural vinyl chloride resin film according to the present invention contains an antifogging agent, an antistatic agent,
It may contain various resin additives such as ultraviolet absorbers, stabilizers, antioxidants, stabilizing aids, fungicides, algaecides, and colorants. Compounds that can be used as antifogging agents include sorbitan resin acid ester, sorbitol fatty acid ester, diglycerin fatty acid ester, glycerin fatty acid ester, sorbitan fatty acid, dibasic acid ester, sorbitol fatty acid, dibasic acid ester, diglycerin fatty acid, Examples include basic acid esters, glycerin fatty acids, dibasic acid esters, and compounds obtained by adding alkylene oxides such as ethylene oxide, propylene, oxide, and butylene oxide to these. Among such compounds, esters of fatty acids having 12 to 22 carbon atoms and dibasic acid esters thereof are preferred. Specific examples of these compounds include sorbitan palmitate, sorbitan stearate, 3 mole adduct of sorbitan stearate and ethylene oxide, 2 mole adduct of sorbitan palmitate and propylene oxide, sorbitol stearate, and 3 mole adduct of sorbitan stearate and ethylene oxide. Molar adduct, diglycene palmitate, diglycene stearate, glycerin stearate, glycerin palmitate/ethylene oxide 2 molar adduct, sorbitan stearate/adipate/propylene oxide 1 molar adduct, sorbitol stearate/adipate/ethylene oxide Examples include a 3 mol adduct of propylene oxide, a 2 mol adduct of diglycerin palmitate sebacate propylene oxide, and a 3 mol adduct of sorbitol palmitate adipate propylene oxide. These specific examples are not intended to limit the invention. These antifogging agents can be used alone or in combination of two or more. Compounds that can be used as antistatic agents include:
Examples include polyoxyethylene alkylamine, polyglycol ether, sodium p-styrenesulfonate, and the like. These antistatic agents can be used alone or in combination of two or more. Examples of compounds that can be used as ultraviolet absorbers include the following. Benzotriazole ultraviolet absorber-2-
(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-
(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2
-(2'-hydroxy-3'-tert-amyl-5'-isobutylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-isobutyl-5'-
methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-isobutyl-5'-
propylphenyl) 5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-
Hydroxy-5'-methylphenyl)benzotriazole, 2-[2'-hydroxy-5'-(1,1,
3,3-tetramethylbutyl)phenyl]benzotriazole. Benzophenone UV absorber -2,2'-dihydroxy-4-methoxybenzophenone, 2,
2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone , 2-hydroxy-4-octoxybenzophenone, salicylic acid-based ultraviolet absorber - phenyl salicylate, para-octylphenyl salicylate The ultraviolet absorbers can be used alone or in combination of two or more types. Among those exemplified above, benzotriazole-based ultraviolet absorbers and benzophenone-based ultraviolet absorbers are particularly preferred. Compounds that can be used as stabilizers include dibutyltin dilaurate, dibutyltin maleate ester, dioctyltin mercaptide, calcium stearate, barium stearate, zinc stearate, calcium laurate, barium ricinoleate, calcium oleate, zinc octoate, etc. I can give it to you. These stabilizers can be used alone or in combination of two or more. Compounds that can be used as antioxidants include:
2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(6-tert-butyl-
(4-ethylphenol), dilaurylthiodipropionate, and the like. These antioxidants can be used alone or in combination of two or more. Compounds that can be used as stabilizing aids include:
Examples include triphenyl phosphite, dioctyl phenyl phosphite, tris(nonylphenyl) phosphite, diphenylisodecyl phosphite, trilauryl trithiophosphite, diphenyl acid phosphite, and dioctyl acid phosphite. These stabilizing aids can be used alone or in combination of two or more. Compounds that can be used as fungicides and algaecides include 2,4,5,6-tetrachloroisophthalonitrile, 10,10'-oxybisphenoxyarsine, 2-(4-thiazolyl)-benz Imidazole, N(fluorodichloromethylthio)phthalimide, N-dimethyl-N'-phenyl-(N'-fluorodichloromethylthio)sulfamide, paraoxybenzoic acid ester, 5-bromo-5-nitro-
Examples include 1,3-dioxane, 2,3,5,6-tetrachloro-4-methylsulfonylpyridine, 3-methyl-4-chlorophenol, N(tetrachloroethylthio)phthalimide, and tributyltin laurate. These compounds are
They can be used alone or in combination of two or more. Examples of colorants that can be used include phthalocyanine blue, phthalocyanine green, Hansa yellow, alizarin lake, titanium oxide, zinc white, permanent red, quinacridin, and carbon black.
These colorants can also be used alone or in combination of two or more. The various resin additives mentioned above should be added to the extent that they do not deteriorate the properties of the film, usually the base vinyl chloride resin.
It can be selected within the range of 5 parts by weight or less per 100 parts by weight. The above (A) component, (B) component, to the base vinyl chloride resin,
In order to allocate component (C) and resin additives, the necessary amounts of each may be weighed and a conventionally known compounding machine or mixer such as a ribbon blender, Banbury mixer, super mixer, or the like may be used. In order to form a film from the resin composition obtained in this way, a method known per se can be used, such as melt extrusion molding method (including T-die method and inflation method), calender molding method, solution casting method. Any conventionally known method may be used. If the thickness of the film is too thin, the strength will be insufficient, which is undesirable.On the other hand, if the film is too thick, it will be inconvenient for film forming work and subsequent handling (including cutting, gluing, and stretching work), so 0.03 ~
The range is preferably 0.3 mm, preferably 0.05 to 0.2 mm. The agricultural vinyl chloride resin film according to the present invention can be used for covering greenhouses, tunnels, etc., and can also be used for mulching, bagging, etc. "Effects of the Invention" The present invention has been described in detail above, and has the following particularly remarkable effects, and its industrial utility value is extremely large. (1) The agricultural vinyl chloride resin film according to the present invention is a polymer with a relatively high average degree of polymerization and a specific plasticizer in a specific range, so the film has excellent cold resistance. Fold wrinkles,
Scratches are less likely to occur, and the film is less likely to tear due to creases or scratches. (2) The agricultural vinyl chloride resin film according to the present invention contains a polymer with a relatively high average degree of polymerization and a specific plasticizer in a specific range, so that the plasticizer does not reach the film surface. There is little blow-out, the films are less likely to "block" together, and have excellent weather resistance. (3) The agricultural vinyl chloride resin film according to the present invention is formulated by combining a polymer with a relatively high average degree of polymerization with a specific plasticity within a specific range, so there is little discoloration during the film forming process. Moreover, film production can be easily carried out. "Examples" The present invention will be described in detail based on Examples below, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Examples 1 to 4, Comparative Examples 1 to 5 Polyvinyl chloride (average degree of polymerization is shown in Table 1) Part by weight Di-2-ethylhexyl phthalate 50 Trixylenyl phosphate 5 Epoxy resin (manufactured by Shell Chemical Co., USA) , trade name "EP-828") 3 Barium-zinc composite liquid stabilizer 1.5 Barium stearate 0.3 Zinc stearate 0.5 Ethylene bisstearamide 0.3 Sorbitan monostearate 2.0 2-(2'-hydroxy A raw material consisting of -5'-methylphenyl)benzotriazole 0.2 〃, a plasticizer, and a resin additive were weighed.
After stirring and mixing these with a super mixer, they were kneaded for 10 minutes on a roll heated to 180°C, and then molded to a thickness of 0.1 mm using an L-shaped calender molding machine.
Nine types of films were produced. Various properties of each film or each film manufacturing composition were evaluated according to the methods described below.
The evaluation results are listed in Table 1. (D) Test related to creases (a) Strength of the part with creases (folding strength) A test film with a size of 100 mm x 100 mm was cut from each film, folded in two along the diagonal, and folded. It was sandwiched between two melamine boards measuring 80 mm x 80 mm. Each sample film was left in a constant temperature room at 23° C. and 50% relative humidity for one week with a load of 100 kg applied to the melamine board. Then, the load was removed, and each sample film was taken out from between the melamine plates, and the folded sample films were left in a constant temperature room at 0°C overnight. Then, slowly expand these sample films, and each sample film conforms to JISP8134 (however, the radius of the triangular pyramid is
(replaced with 1/2 inch hemispherical shape), capacity 100Kg・cm,
Impact strength was measured at an impact speed of 2.2 m/sec. (b) Strength after recovering the wrinkled part (crease recovery strength) In the same way as in (a) above, cut the film, sandwich each sample film between melamine plates, and apply a load of 100 kg. It was left for one week under the load. Then, the load was removed from each sample film, and it was taken out from between the melamine plates, and each sample film, still folded, was left in a constant temperature room at 23° C. and 50% relative humidity for one week. Next, each sample film, still folded, was
It was left in a constant temperature room at 0°C all day and night. These sample films were then slowly expanded, and the impact strength of each sample film was measured in the same manner as in (a) above. In the tests (a) and (b), a film that shows a value of 250 kg/cm/mm or more means that it has excellent cold resistance and is unlikely to tear the film due to creases. (E) Scratch Resistance Related Test (Scratch and Tear Strength) Test films with a size of 100 mm x 100 mm were cut from each film, and the temperature was controlled in a constant temperature room at 23° C. and 50% relative humidity. Place each sample film on 320-mesh sandpaper in a constant temperature room, and place a 100 g weight (base area approximately 4.5 mm) in the center of the film.
cm ² ) was placed on the sample film, one end of the film was gripped by hand, and the film was moved horizontally on the sandpaper at a speed of about 240 cm/min to make a scratch on the flat surface of each sample film. For each sample film after scratching,
Impact strength was measured in the same manner as described in (A) and (a) above. In this test, a value of 250 kg cm/mm or more means that the film is less likely to tear due to scratches. (F) Blocking resistance test A test film of 50 mm x 300 mm was cut from each film, and the temperature was controlled in a constant temperature room at 23° C. and 50% relative humidity. Each sample film was wound around a test tube with a diameter of 15 mm and a length of 150 mm in a thermostatic chamber while applying a load of 1.0 kg to one end in the length direction. The test tube wrapped with the sample film as above was placed in a desiccator filled with water at the bottom, and the desiccator was left in a small room maintained at 50°C for one week. After standing, the desiccator was taken out of the small room, the test tube was wrapped with a film, and the test tube was taken out from the desiccator and left overnight in a constant temperature room at 23°C and 50% relative humidity. Weights of different weights are sequentially attached to the outer edge of the sample film wrapped around a test tube via adhesive tape, and the test tube is supported pivotably for each weight, and the sample film is released. The weight was rotated in the (unwinding) direction, and the minimum weight of the weight when the sample film began to be released (unwinding) was measured. This value is "peel strength" (g/50mm)
And so. This "peel strength" means that the smaller the value, the less blocking occurs between films. (G) Weather resistance test Nine types of films were tested in a field with a width of approximately 2m and a depth of approximately 25cm.
outdoor airtight test house facing south with a ridge height of approximately 1.5 m and a roof slope of approximately 45 degrees (location: Isshi District, Mie Prefecture)
It lasted for 12 months from July 1, 1980 to June 30, 1988. After 12 months, each film was visually observed and its weather resistance grade was determined. The criteria for determining the grade were as follows. 5... No brown spots observed 4... Very few brown spots observed 3... A few brown spots observed 2... Many brown spots observed 1... Brown spots Those with extremely many spots (H) Film molding processability () test... Each composition for film production was
After kneading for 10 minutes on a kneading roll heated to 180°C, a film with a thickness of 0.2 mm was prepared. The nine types of films obtained were subjected to a heat resistance test using a gear oven tester at a temperature of 180°C, and the time (minutes) until the films blackened was measured. The longer this time (minutes), the better the heat resistance and the less discoloration, which means that the processability during film formation is better. () Test...each composition for film production,
After kneading for 10 minutes on a kneading roll heated to 180°C, a film with a thickness of 0.2 mm was prepared. The peelability of this film when peeled from the kneading roll and the transparency of the obtained film were observed, and the "grade" was determined. The criteria for determining the grade were as follows. ○...Good releasability and transparency. △...Poor in either releasability or transparency. ×...Poor in both releasability and transparency.

[Table] From Table 1, the following becomes clear. (1) The film of the example has high fold strength and high strength in the fold wrinkle recovery test, and the film is less likely to tear due to fold wrinkles. (2) The films of Examples have high scratch and tear strength, and even if there are scratches on the film surface, the film is unlikely to tear due to scratches. (3) In the films of Examples, blocking does not easily occur even when the films are stacked on top of each other and left under harsh conditions of high temperature and high humidity. (4) The film of the example is easy to process into a film. (5) On the other hand, none of the films of Comparative Examples showed excellent properties in all of the fold strength, crease recovery test, scratch tear strength, blocking resistance, and film-forming work. Examples 5 to 9, Comparative Examples 6 to 9 Polyvinyl chloride (=2100) 100 parts by weight Phthalate ester plasticizer Amount shown in Table 2 Phosphate ester plasticizer Epoxidized plasticizer Barium-zinc composite Liquid stabilizer 1.5 parts by weight Barium stearate 0.3 Zinc stearate 0.5 Ethylene bisstearamide 0.5 Sorbitan monostearate 2.0 2-(2'-hydroxy-5'-methylphenyl) benzotriazole 0.2 Raw materials, The plasticizer and resin additives were weighed.
These were stirred and mixed using a super mixer, then kneaded for 10 minutes on a roll heated to 180°C, and nine types of films each having a thickness of 0.1 mm were produced using an L-shaped calender. Various properties of each film or each film manufacturing composition were evaluated in the same manner as in the previous example.
The evaluation results are shown in Table 2.

[Table] From Table 2, the following becomes clear. (1) Like the films shown in Table 1, the film of the present invention has excellent properties in all aspects of fold strength, crease recovery test, scratch tear strength, blocking resistance, and workability when forming into a film. It shows. (2) On the other hand, the one containing less phthalate plasticizer (Comparative Example 6) is inferior in fold strength, crease recovery test, and scratch tear strength, and is also inferior in workability when forming into a film. The one containing a large amount of phthalate ester plasticizer (Comparative Example 9) has a high crease strength,
It also has poor crease recovery strength, poor blocking resistance, and poor workability when forming into a film. (3) Furthermore, the film containing no phosphate plasticizer (Comparative Example 7) had extremely poor weather resistance, and the film containing no epoxy plasticizer (Comparative Example 8) had poor weather resistance. The workability of film production is poor.

Claims (1)

[Claims] 1. Vinyl chloride resin with an average degree of polymerization of 1500 to 2500
To 100 parts by weight, (A) 30 to 70 parts by weight of a phthalate ester plasticizer, (B) 1 to 7 parts by weight of a phosphate ester plasticizer, and (C) 0.5 to 7 parts by weight of an epoxidized plasticizer are blended. An agricultural vinyl chloride resin film characterized by being formed into a film. 2. Claim 1, characterized in that the total amount of the three components (A), (B), and (C) is 40 to 80 parts by weight based on 100 parts by weight of the vinyl chloride resin. The agricultural vinyl chloride resin film described above. 3 The ratio of (A) to (B) is 1:1/5 to 1/35 by weight, and the ratio of (A) to (C) is 1:1/10 to 1/100 by weight. An agricultural vinyl chloride resin film according to any one of claims 1 to 2, characterized in that: