JPS6210125B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an antifogging synthetic resin film. More specifically, the present invention relates to an antifogging synthetic resin film that has excellent antifogging properties at low temperatures and long lasting antifogging properties at high temperatures. Conventionally, when food products such as vegetables and meat are packaged with thermoplastic synthetic resin films that do not transmit water vapor, water droplets often cover the inner surface of the film, damaging the transparency of the film itself. These water droplets not only cloud the transparent film and make it difficult to see the contents, but also cause the condensed water droplets to adhere to the stored food and cause bacterial growth. On the other hand, synthetic resin films used in the agricultural field are mainly used as covering materials for greenhouses and tunnels, and the anti-fogging properties of the film are also an important performance in this application. When used as a covering material, moisture evaporating from the soil or cultivated plants causes water droplets to adhere to the inner surface of the film, making it opaque, thereby reflecting or blocking sunlight and inhibiting the growth of cultivated plants. Not only will it damage the plants, but the condensed water droplets will fall on the cultivated plants, causing diseases and quality deterioration. In order to improve the above-mentioned drawbacks, a method of adding a so-called antifogging agent to the base resin has been widely used in order to impart hydrophilicity to the surface of the synthetic resin film (for example, Japanese Patent Publication No. 38-3572, Kosho 48−
Publication No. 31748, Special Publication No. 51-39669, Publication No. 39669, Special Publication No. 52
(See Public Law No. 26532, Special Publication No. 55-9431, etc.) Synthetic resin films for food packaging must exhibit antifogging properties even when food is packaged and stored in a cold place for a long time. On the other hand, synthetic resin films used for agricultural purposes exhibit anti-fogging properties even in the low-temperature period of winter, and the anti-fog agent does not extract and wash away even during the high-temperature period of summer, and is resistant to ultraviolet rays. It must maintain its antifogging properties without decomposing. However, with the technology described in the above publication, (1)
There was no product that had good anti-fogging properties at low temperatures (low-temperature properties) and (2) maintained its anti-fogging properties for a long period of time even when exposed to high temperatures (excellent sustainability). Under such circumstances, the present inventors have completed the present invention as a result of intensive studies aimed at providing an antifogging synthetic resin film that has both of the above two properties. Therefore, the gist of the present invention is to provide 100 parts by weight of a synthetic resin with a hexahydric alcohol (hexittol) obtained by reduction of sugars (hexoses) and/or with 1 to 2 molecules of water from these alcohols. It is a higher fatty acid polyhydric alcohol partial ester mixture obtained by esterifying polyhydric alcohols obtained by separation and higher fatty acids as raw materials, and the content ratio of diesters is
A low-temperature protection film containing 1 to 5 parts by weight of 20 to 80% by weight and a sum of 80 to 20% by weight of monoesters and triesters. An anti-fogging synthetic resin film having excellent fogging properties and anti-fogging durability at high temperatures (first invention). Furthermore, the substances blended into the base synthetic resin are the above (A) higher fatty acid polyhydric alcohol partial ester mixture and (B) an alkylene oxide addition type higher grade compound having a chemical structure in which alkylene oxide is added to the above component (A). An antifogging synthetic resin film characterized by being a mixture consisting of a fatty acid polyhydric alcohol partial ester mixture (second invention). The present invention will be explained in detail below. In the present invention, the synthetic resin generally includes film-forming thermoplastic synthetic resins. Specifically, vinyl chloride resins such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylic acid ester copolymer, vinyl chloride-methacrylic acid ester copolymer; polyethylene, polypropylene, ethylene- Olefin resins such as vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic ester copolymer, ethylene-methacrylic ester copolymer, ethylene-butylene copolymer; polyethylene terephthalate, polyamide, poly methyl methacrylate,
Refers to polyacrylate, polycarbonate, polyvinyl acetate, fluorine-containing resin, etc., or blends of these polymers. For agricultural cover uses,
From the viewpoints of weather resistance, light transmittance, economy, strength, workability, etc., vinyl chloride resins and olefin resins are preferred, and polyvinyl chloride is most advantageous. These synthetic resin base materials contain sugars (hexose).
Hexahydric alcohol (hexittol) obtained by the reduction of and/or 1 from these alcohols
~A higher fatty acid polyhydric alcohol partial ester mixture obtained by esterifying a polyhydric alcohol obtained by separation of two molecules of water and a higher fatty acid as raw materials, comprising monoesters, diesters and A specific amount of triesters with a specific content ratio is blended (first invention). Furthermore, the above (A) higher fatty acid polyhydric alcohol partial ester mixture, and (B) the alkylene oxide-added higher fatty acid polyhydric alcohol partial ester mixture having a chemical structure in which alkylene oxide is added to the above (A) component. A specific amount of a mixture consisting of component (A) and component (B) is blended (second invention). In the present invention, polyhydric alcohol refers to hexavalent alcohol (hexitutol) obtained by reduction of sugars (hexoses),
It refers to a polyhydric alcohol (hexitane) obtained by removing a molecule of water, and a polyhydric alcohol (hexide) obtained by removing one molecule of water from hexitane. These polyhydric alcohols are single species,
It may be a mixture of multiple alcohols in the same category or a mixture of alcohols in different categories. Among the polyhydric alcohols mentioned above, specific examples of hexytol include sorbitol,
Examples include mannitol (mannitol), iditol (iditol), talitol (talitol), dulcitol (dulcitol), allodulcitol (allotulcitol), and the like. Specific examples of hexitane include sorbitan, mannitan, iditutan, talitutan, dulcittan, allodulcittan, and the like. Specific examples of hexide include sorbide, mannide, oxidide, talitd, dulsitide, allodursid, and the like. Among the above polyhydric alcohols, sorbitol-based polyhydric alcohols (sorbitol, sorbitan, sorbite) and/or mannitol-based polyhydric alcohols (mannitol, mannitan, mannide) are esterified with higher fatty acids. When the obtained product is blended into a synthetic resin film, the antifogging effect and antifogging durability are particularly excellent, which is particularly preferable. As the higher fatty acid to be subjected to the esterification reaction with the polyhydric alcohol, a fatty acid having 12 to 22 carbon atoms is suitable. Specifically, fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and oleic acid, as well as beef tallow, rapeseed oil, corn oil, soybean oil, cottonseed oil, palm oil, sesame oil, linseed oil, or Mention may be made of mixed fatty acids obtained from hydrogenated oils. Among them, fatty acids include palmitic acid and/or stearic acid.
If the mixed fatty acid contains more than % by weight, the synthetic resin film containing the fatty acid polyhydric alcohol ester obtained by esterification with the polyhydric alcohol will have excellent anti-fogging effect and anti-fogging durability. preferable. When making an ester by reacting the above polyhydric alcohol with the above higher fatty acid, (a) an ester in which all of the hydroxyl groups of the polyhydric alcohol undergo an esterification reaction with a fatty acid, and (b) a portion of the hydroxyl group of the polyhydric alcohol. is obtained as a mixture of three components: a partial ester obtained by esterification reaction with a fatty acid, and (c) an unreacted product. According to the experiments of the present inventors, among higher fatty acid polyhydric alcohol esters, the esters mentioned in (a) above
Regarding the partial esters in (B), the effectiveness of the antifogging properties and antifogging durability of the synthetic resin film obtained by blending each of them is different, that is, in (B) above.
The above (b) is better than the film containing esters.
It was found that the film containing the partial esters had better antifogging properties at low temperatures and antifogging durability at high temperatures. Furthermore, monoesters, diesters, and triesters are separately extracted from the higher fatty acid polyhydric alcohol partial ester (b), and the antifogging properties and antifogging durability of a synthetic resin film containing each ester are evaluated. We investigated the effectiveness of the As a result, the effect of imparting hydrophilicity to the surface of a synthetic resin film is in the order of monoesters > diesters > triesters, and that diesters and triesters are each superior in terms of the anti-fog lasting effect. I understood. Based on the above experimental results, we found that (1) anti-fog properties at low temperatures (low-temperature properties) are good, and (2) anti-fog properties last for a long time even when exposed to high temperatures (excellent sustainability).
In order to obtain
It has been found that the total content of monoesters and triesters is preferably in the range of 80 to 20% by weight. Within the above range, a proportion in which the diester content exceeds the sum of the monoester and triester content is particularly preferred. The antifogging synthetic resin film according to the present invention has the above-mentioned properties.
(A) Part of the higher fatty acid polyhydric alcohol partial ester mixture is replaced with (B) an alkylene oxide-added higher fatty acid polyhydric alcohol partial ester mixture having a chemical structure in which alkylene oxide is added to the component (A) above, ( Component A) and component (B) can be blended together (second invention). Examples of the alkylene oxide that can be added to the higher fatty acid polyhydric alcohol partial ester include ethylene oxide, propylene oxide, butylene oxide, phenylene oxide, polyethylene oxide, polypropylene oxide, polybutylene oxide, and the like. The above (A) component or (A) component to the base synthetic resin
The total amount of component (B) is in the range of 1 to 5 parts by weight based on 100 parts by weight of the synthetic resin. If the amount is less than the above range, the antifogging properties of the synthetic resin film will be unfavorable, while if it is more than the above range, it may bleed out onto the film surface, which is undesirable. The synthetic resin base material constituting the synthetic resin film of the present invention may also contain various conventional resin additives, such as plasticizers, lubricants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, and dyes, as necessary. etc., in conventional amounts. For example, regarding the soft vinyl chloride resin suitable for the present invention, about 100 parts by weight of polyvinyl chloride having a degree of polymerization of about 1000 to 2000, about
It can be blended in a proportion of 30 to 70 parts by weight. 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 diundecyl phthalate; Ilphthalic 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; Itacon such as monobutyl itaconate Acid derivatives; oleic acid derivatives such as butyl oleate; ricinoleic acid derivatives such as glycerin monocitrate; other tricresyl phosphate;
Examples include epoxidized soybean oil and epoxy resin plasticizers. In addition, examples of lubricants or heat stabilizers that can be included in the synthetic resin base material include polyethylene wax,
Examples include bisamide, stearic acid, zinc stearate, barium stearate, calcium stearate, barium ricinoleate, and the like. Examples of the ultraviolet absorber include benzotriazole-based, benzoate-based, benzophenone-based, cyanoacrylate-based, and phenyl salicylate-based ultraviolet absorbers. Examples of pigments and dyes include titanium oxide, silica, ultramarine blue, and phthalocyanine blue. These resin additives may be contained in a small amount of 5 parts by weight or less per 100 parts by weight of the synthetic resin base material. The above (A) component or (A) component is added to the base synthetic resin.
To blend the component (B) and further include various resin additives if necessary, use ordinary blending techniques and mixing techniques, such as a ribbon blender, Banbury mixer, super mixer, and other blenders and mixers. It is possible. In order to form a film from a synthetic 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 antifogging synthetic resin film according to the present invention is too thin, it will not have sufficient strength, and on the other hand, if it is too thick, it will not be suitable for cutting, gluing, etc. when used for packaging, agricultural purposes, etc. Because it causes inconvenience,
The range is preferably 0.01 to 0.5 mm. As explained above, the anti-fog film according to the present invention, like the various anti-fog films conventionally used, can be used for packaging various foods and for covering greenhouses or tunnels for cultivating useful plants. be able to. When the anti-fog synthetic resin film according to the present invention containing component (A) or components (A) and (B) is used for packaging vegetables or meat, it may not be stored in a cool place for a long period of time. Demonstrates anti-fog properties even when Furthermore, when the antifogging synthetic resin film according to the present invention is used as a cover for a greenhouse for cultivating useful plants,
It exhibits anti-fog properties even in the low-temperature period of winter, and the anti-fog agent does not extract and leak out even during the high-temperature period of summer, and does not decompose due to ultraviolet rays, demonstrating excellent anti-fog durability. Therefore, the antifogging synthetic resin film according to the present invention has extremely great utility value in food packaging or agricultural cover applications. Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Examples 1 to 6, Comparative Examples 1 to 4 Polyvinyl chloride (=1300) 100 parts by weight Dioctyl phthalate 50 Barium-zinc liquid stabilizer 2 Barium-zinc powder stabilizer 1 The basic composition was The antifogging agent shown in Table 1,
2 parts by weight were added to 100 parts by weight of polyvinyl chloride (however, it was not added in Comparative Example 3). The mixture was fed into a calender heated to 180°C and formed into a film using a conventional method to a thickness of 0.1
Nine types of mm films were created. The antifogging properties of the above nine types of films and commercially available agricultural vinyl chloride films (thickness 0.1 mm) were evaluated according to the following method. <Evaluation of anti-fog properties> A field with a width of 2 m and a ridge height of 2
A single-roof type house with a length of 20 m and a depth of 20 m was coated with the nine types of films described above (December 11, 1980), and the antifogging properties of each film were visually observed and evaluated. The results are shown in Table 1. The numerical values of "antifogging performance evaluation" have the following meanings. "1": Water adheres in a thin film and no water droplets are observed. "2": Water is attached in a thin film, but slightly large water droplets are observed. "3": Water is attached in a thin film, but large water droplets are observed to be attached in some areas. “4”……A state in which fine water droplets are observed to be partially attached. "5"...A state in which fine water droplets are observed to adhere to the entire inner surface of the film.

[Table] From Table 1, the following becomes clear. (1) Although the film according to the present invention is as thin as 0.1 mm, it can be used over two winter seasons. On the other hand, the antifogging properties of commercially available agricultural vinyl chloride films of the same thickness are extremely reduced after one winter season use. (2) When the composition of the higher fatty acid polyhydric alcohol partial ester is within the claimed range, the anti-fogging properties and anti-fogging durability of the films containing it (Examples 1 to 6) are excellent. However, if it is outside the scope of the claims, the antifogging properties and antifogging durability of the films containing this (Comparative Examples 1 and 2) will not be very good. (3) In the higher fatty acid polyhydric alcohol partial ester mixture, when the content ratio of diesters exceeds the content ratio of the sum of monoesters and triesters, excellent antifogging durability is exhibited (Example 3 and Example 4).

Claims (1)

[Scope of Claims] 1. Hexahydric alcohol (hexittol) obtained by reduction of sugars (hexose) and/or separation of 1 to 2 molecules of water from these alcohols based on 100 parts by weight of synthetic resin. It is a higher fatty acid polyhydric alcohol partial ester mixture obtained by esterifying the obtained polyhydric alcohol and higher fatty acid as raw materials, and the content of diesters is 20 to 80% by weight, and monoester and A film containing 1 to 5 parts by weight of a compound containing 80 to 20% by weight in combination with triesters, which exhibits antifogging properties at low temperatures and long-lasting antifogging properties at high temperatures. Excellent anti-fog synthetic resin film. 2. Antifogging according to claim 1, characterized in that in the higher fatty acid polyhydric alcohol partial ester mixture, the content of diesters exceeds the sum of the content of monoesters and triesters. synthetic resin film. 3. The antifogging synthetic resin film according to claim 1 or 2, wherein the synthetic resin is an olefin resin or a soft blended vinyl chloride resin. 4. Antifogging synthesis according to claims 1 to 3, wherein the polyhydric alcohol is a sorbitol polyhydric alcohol and/or a mannitol polyhydric alcohol. resin film. 5. The antifogging synthetic resin film according to claims 1 to 4, characterized in that the synthetic resin film is used for agricultural cover. 6. The antifogging synthetic resin film according to claims 1 to 5, wherein the higher fatty acid is a fatty acid containing 50% by weight or more of palmitic acid and/or stearic acid. 7 For 100 parts by weight of synthetic resin, (A) hexahydric alcohol (hexitutol) obtained by reduction of sugars (hexose) and/or polyhydric alcohol obtained by separation of 1 to 2 molecules of water from these alcohols. It is a higher fatty acid polyhydric alcohol partial ester mixture obtained by esterifying the raw materials of alcohols and higher fatty acids, and the content of diesters is 20 to 80% by weight, monoesters and triesters. and (B) an alkylene oxide-added higher fatty acid polyhydric alcohol moiety having a chemical structure in which alkylene oxide is added to the above-mentioned higher fatty acid polyhydric alcohol partial ester mixture. An anti-fogging synthetic resin film comprising 1 to 5 parts by weight of an ester mixture. 8 In the higher fatty acid polyhydric alcohol mixture,
The antifogging synthetic resin film according to claim 7, characterized in that the content of diesters exceeds the sum of the content of monoesters and triesters. 9. The antifogging synthetic resin film according to claims 7 to 8, wherein the synthetic resin is an olefin resin or a soft blended vinyl chloride resin. 10 Antifogging synthesis according to claims 7 to 9, characterized in that the polyhydric alcohol is a sorbitol polyhydric alcohol and/or a mannitol polyhydric alcohol. resin film. 11. The antifogging synthetic resin film according to claims 7 to 10, characterized in that the synthetic resin film is used for agricultural cover. 12. The antifogging synthetic resin film according to claims 7 to 11, wherein the higher fatty acid is a fatty acid containing 50% by weight or more of palmitic acid and/or stearic acid.