JPH0114928B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for improving the anti-fog durability of an anti-fog film. Thermoplastic resin films, especially polyvinyl chloride films, are often used for greenhouses, but anti-fog treatments are now being applied to prevent the interior surfaces of the films from fogging up and from getting wet. . This is to prevent the transmittance of sunlight from being obstructed by cloudiness and to prevent water droplets adhering to the film surface from falling onto the cultivated crops and damaging them. For the antifogging treatment, a method is used in which a film is coated with an antifogging agent such as a sorbitan ester, or a film is made of a polymer mixed with an antifogging agent. The outdoor surface of the greenhouse film covered with such an anti-fog film is often exposed to wind and rain, and the indoor surface is constantly wet with water, so the anti-fog agent evaporates from the film to a large extent. The durability of the antifogging performance of the film was low. As a method for improving this drawback, Japanese Patent Publication No. 31195/1983 proposes a method of applying an acrylic resin paint to one side of the antifogging film. but,
Acrylic resin itself does not have great barrier properties against antifogging agents and plasticizers, and since a solvent is used during coating, the antifogging agents and plasticizers eluted are contained in the acrylic resin coating, and the antifogging agent and plasticizer of the underlying layer are Because the subsequent migration of antifogging agents and plasticizers from the fogging film layer becomes active, the antifogging performance deteriorates over time, and there is a problem that the antifogging performance usually decreases in the middle of one season. . Of course, methods have been proposed such as using a solvent for acrylic resin paint that does not dissolve polyvinyl chloride or using an aqueous dispersion of acrylic resin as a paint, but these methods limit the amount of acrylic resin used. However, it has various problems. In view of the above, the present inventors have conducted extensive research into methods for improving the anti-fog durability of an anti-fog film that will maintain its anti-fog performance for at least one season, and have finally arrived at the present invention. That is, the present invention is characterized in that an ultraviolet curable coating is applied to a thickness of 0.5 to 10 μm on one side of an antifogging film, and cured by ultraviolet irradiation, thereby improving the antifogging durability of the non-coated side of the coating. The present invention relates to a method for improving the anti-fog durability of an anti-fog film. Ultraviolet curable paints can be applied with almost no solvent, so there is very little chance of the antifogging agent or plasticizer in the antifogging film getting into the coating layer.
Because it is cross-linked, the anti-fog agent and plasticizer hardly seep out from the paint film, and the barrier effect of the paint film itself is very good, so it is thought that the anti-fog durability will be greatly improved. It will be done. UV-curable paints include acrylic (including acrylic modified urethane, acrylic modified polyester, and acrylic modified epoxy), polythiol, and epoxy paints. Among these, epoxy-based and polythiol-based ultraviolet curing paints are preferred, and epoxy-based paints are particularly preferably used. As the film base material for the antifogging film of the present invention, a thermoplastic resin film can be used, but a vinyl chloride polymer film is most commonly used in terms of cost, transparency, weather resistance, and other properties.
Vinyl chloride polymers include polyvinyl chloride, vinyl chloride and other monomers such as ethylene,
Copolymers with vinyl acetate, vinyl ether, maleic acid ester, etc., and blends of these polymers with each other or with other polymers are included. For these polymers, the film has moderate flexibility,
Needless to say, it is possible to contain a plasticizer for imparting extensibility, other lubricants, stabilizers, ultraviolet absorbers, antioxidants, pigments, inorganic substances, antistatic agents, etc. In the present invention, all kinds of antifogging agents can be used, regardless of whether they are known or new, and the type is not specified in any way, but (A)
Ether types such as polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, and polyoxyethylene polyoxypropylene ether; (B) Ester types such as polyoxyethylene alkyl ester and partial esterification of polyhydric alcohol and fatty acid; (C) Aminoether type products such as polyoxyethylene alkylamine, (D) Polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene mannitan fatty acid ester, polyoxyethylene glyceryl fatty acid ester, Examples include ether ester types such as polyoxyethylene propylene glycol monofatty acid ester. These antifogging agents can basically be selected arbitrarily, but preferably they have properties such as moldability, heat resistance, transparency, etc. in addition to maintaining antifogging properties, and are suitable for agricultural coatings. It is desirable to fully satisfy the performance as a material. Examples of suitable antifogging agents for achieving the above performance include (i) partial esters of polyhydric alcohols such as sorbitan, sorbitol, mannitan, mannitol, glycerin, diglycerin, and fatty acids having 12 to 22 carbon atoms (ii) ) The number of moles of ethylene oxide or propylene oxide added is 1 to 20, the polyhydric alcohol is sorbitan, sorbitol, mannitan, glycerin, diglycerin, and the number of carbon atoms in the fatty acid is 12 to 20.
22, a mixture of polyoxyalkylene polyhydric alcohol fatty acid ester (iii) (i) and (ii). These antifogging agents are used in an amount of at least 0.5 parts by weight, preferably 1.0 to 1.0 parts by weight, per 100 parts by weight of the vinyl chloride resin.
Add in a range of 5.0 parts by weight. If the amount added is less than 0.5 parts by weight, a sufficient antifogging effect cannot be obtained, and if it exceeds 5.0 parts by weight, there will be a lot of bleeding, water absorption will easily cause whitening, and transparency will decrease, which is not preferable. These antifogging agents may be applied to a base film, or may be mixed with a polymer to form a film. The latter is common as an anti-fog film. The epoxy ultraviolet curable coating used in the present invention includes, for example, a monomer having an epoxy group and/or
Alternatively, a photosensitive aryldiazonium compound is mixed with a resin. The epoxy resin monomer has an epoxy ring represented by the following structural formula.

[Formula] (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are alkyl, aryl, alkoxy, alkenyl and hydrogen.) Specific examples of the above monomers include ethylene oxide and homologs thereof: Glycidic acid and glycidyl esters: glycidyl methacrylate, acrylate and crotonate: and allyl glycidyl ether. The epoxy resin low polymer is preferably a low polymer of the above-mentioned monomers, has a dissolving ability capable of dissolving the film surface, and is liquid at room temperature. The photosensitive aryldiazonium compound used in the present invention is represented by the following structural formula. (In the formula, MX _o+n is hexachlorostannate,
A complex anion containing a halogen selected from tetrachloropherate, hexafluoroarsenate, hexachloroantimonate, hexafluoroantimonate and bismuth chloride, and Y is nitro, halogen, N-morpholino, alkyl, alkoxy, aryl. ,amino,
selected from the group consisting of arylamino, alkylamino and arylmercapto groups. Further, m is equivalent to the number of halogen atoms of the Lewis acid produced upon exposure to ultraviolet rays, that is, the charge of the complex cation. ) When exposed to ultraviolet light, the above aryldiazonium compounds form Lewis acids of the general formula MX _o (i.e., _PF3 , _FeCl3 , _AsF5 , _SnCl4 and _BiCl5 , etc.)
The Lewis acid initiates the polymerization of the epoxy resin monomer and/or its low polymer. Specific examples of the aryldiazonium compounds include p-methoxybenzenediazonium hexafluorophosphate, o-nitrobenzenediazonium hexafluorophosphate,
2,5-dichlorobenzenediazonium hexafluorophosphate, 2,5-diethoxy-4-
diazonium hexafluorophosphate such as p-trimercaptobenzenediazonium hexafluorophosphate, p-N-morpholinophenyldiazonium hexafluorophosphate,
2,5-dimethoxy-4-N-morpholinobenzenediazonium hexafluorophosphate, p
Examples include N-morpholino complexes such as -N-morpholinophenyldiazonium hexafluoroantimonate and p-N-morpholinophenyldiazonium hexafluoroantimonate. As a polythiol-based ultraviolet curable coating, a sensitizer is added to polyene and/or polyol and polythiol, as seen in Japanese Patent Publication No. 47-3269, Japanese Patent Application Laid-open No. 53-134096, etc., and the coating is cured by ultraviolet irradiation. It hardens and can be flexible. Acrylic UV-curable paints are mainly composed of compounds with acrylic or methacrylic groups at their terminals, and oligomers such as acrylic-modified urethane, acrylic-modified epoxy, and acrylic-modified polyester can be used, and the hardness and degree of crosslinking can be adjusted. Therefore, various acrylic monomers can be used. The average thickness of the film of the above UV-curable paint is
It is preferably 0.5 to 10μ. If the average thickness is less than 0.5μ, the anti-fog durability improvement effect is insufficient.
If it exceeds 10μ, the elongation of the coated film decreases, which is not preferable. Examples are shown below. Examples and Comparative Examples A composition with the following formulation was calendered, and the thickness
A 0.1 mm anti-fog film was created (referred to as film F1). Polyvinyl chloride 100 (parts by weight) Plasticizer [DOP (45), TCP (5)] ⁽¹⁾ 50 Stabilizer 4 EO adduct of sorbitan monostearate ⁽²⁾
1 Sorbitan monopalmitate 1 Lubricant 0.2 (Notes (1) (2): DOP: Dioctyl phthalate, TCP:
Tricresyl phosphate, EO: ethylene oxide) Adeka Ultraset on one side of film F1
#7200 (manufactured by Asahi Denka KK, epoxy UV-curable paint) was applied to a thickness of approximately 3 μm and cured by UV irradiation (designated film F2). Polythiol-based UV-curable paint #2311B manufactured by WR Grace was applied to a thickness of approximately 3μ on one side of Film F1, and cured by UV irradiation (Film
F3). Konidaku V-4601 (manufactured by Dainippon Ink, acrylic ultraviolet curable paint) was applied to a thickness of about 3 μm on one side of film F1, and cured by irradiation with ultraviolet rays (referred to as film F4). Dianal BR-60 on one side of film F1
(manufactured by Mitsubishi Rayon, acrylic resin) was applied and dried to form a coating film with a thickness of approximately 3μ (designated film F5). A small house was made using the above five films and its anti-fog performance was evaluated for one year. The results are shown in Table 1.

【table】

Table 1 The results in Table 1 show that the anti-fog durability of the anti-fog film according to the invention is significantly improved.

Claims (1)

[Claims] 1. Ultraviolet curable paint applied on one side of the anti-fog film.
A method for improving the anti-fog durability of an anti-fog film, which comprises applying the coating to a thickness of 0.5 to 10 μm and curing it by irradiation with ultraviolet rays to improve the anti-fogging durability of the non-coated surface of the coating. 2. The method for improving the antifogging durability of an antifogging film according to claim 1, wherein the ultraviolet curable coating is an epoxy or polythiol coating.