JPH09123364A - Agricultural polyethylene terephthalate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agricultural polyethylene terephthalate film which makes it possible to detect the defogging properties in a short time and to largely improve the continuity thereof. SOLUTION: The agricultural polyethylene terephthalate film comprises a film made of acrylic resin having a thickness of 1 to 10μm mixed with ultraviolet absorber formed on one side surface of a biaxially oriented polyethylene terephthalate film and a film derived from defogging composition containing (a) water dispersant of hydrophobic acrylic resin having a glass transition temperature obtained by polymerizing 60 to 100wt.% of mixture of (meth)acrylate alkyl ester or (meth)acrylate alkyl ester and alkenyl benzene, and 0 to 40wt.% of α-, β-ethylenically unsaturated monomer copolymerizable therewith of a range of 35 to 80 deg.C, (b) inorganic colloidal sol, and (c) 0.01 to 30 pts.wt. of water soluble inorganic chlorine compound to 100 pts.wt. of solid content of the component (b) formed on the other surface.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an agricultural polyethylene terephthalate film. More specifically, excellent mechanical strength, excellent weather (light) resistance,
The present invention relates to an agricultural polyethylene terephthalate film having excellent antifogging properties.

[0002]

2. Description of the Related Art In general, a polyethylene terephthalate film has high crystallinity, high melting point, excellent heat resistance and chemical resistance, and excellent mechanical properties such as strength and elastic modulus. It is known to show. Therefore, the polyethylene terephthalate film is widely used not only for magnetic tape but also for photography, electricity, metallization, packaging, agriculture, and the like.

[0003] However, since the polyethylene terephthalate film has a hydrophobic surface, if it is used as a covering material for an agricultural house (greenhouse), depending on conditions such as temperature and humidity in the house, the inside of the film may be degraded. Causes fogging on the surface. This haze reduces the amount of light passing through the film, slows down the growth of the plant, or causes water drops to fall on the cultivated plant, causing damage to the germ or causing disease, Various inconveniences occur, such as giving an unpleasant feeling to the worker in the house.

[0004] It is known that in order to eliminate such inconvenience, it is only necessary to impart antifogging properties to the film surface.
In order to impart anti-fogging property to the film surface, a method of kneading a hydrophilic substance such as a surfactant into a film, or a method of applying a hydrophilic substance or a water-soluble polymer substance to the film surface, etc. Are known. However, the former method is less effective with a hard resin such as polyethylene terephthalate, and attempts have been made to impart antifogging property by the latter method.

As a material imparting hydrophilicity, for example, Japanese Unexamined Patent Publication No. 51-81877 discloses an alumina sol obtained by adding a surfactant and a hydrophilic polymer;
JP-A-2007-974, JP-A-59-15473, and the like disclose those obtained by adding a hydrophilic polymer and a surfactant to colloidal silica. However, since a hydrophilic polymer such as polyvinyl alcohol or a hydroxyl group-containing acrylic resin is blended in these compositions for the purpose of exhibiting miscibility with an inorganic aqueous sol, the formed coating film tends to be essentially inferior in water resistance. There is. Therefore, if the inorganic aqueous sol is constantly exposed to humid conditions, the inorganic aqueous sol is washed away with the hydrophilic polymer or causes poor dispersion, and the antifogging effect is impaired in a short period of time, which is not practically satisfactory.

[0006]

In order to solve the above-mentioned drawbacks, an invention relating to an antifogging agent composition comprising a hydrophobic acrylic resin having a glass transition temperature in the range of 35 to 80 ° C. and an inorganic colloid sol has been proposed. JP 62-24698
Although it was proposed as No. 4, although it has excellent antifogging sustainability, there is a problem that it takes a long time to develop the antifogging property.

[0007]

Under these circumstances, the inventors of the present invention show excellent weather resistance (light resistance) without lowering the mechanical strength even after long-term use such as for house coating. And, in order to provide a polyethylene terephthalate film for agriculture, which is excellent in the speed of development of antifogging property and whose antifogging property is maintained for a long period of time, as a result of extensive studies, the present invention has been completed. .

However, the gist of the present invention is that a biaxially stretched polyethylene terephthalate film has a UV absorbent on one side and a thickness of 1 to 1
A polyethylene terephthalate film for agricultural use, which comprises a 0 μm acrylic resin-based coating film, and on the other surface a coating film derived from an antifogging agent composition containing the following components (a) to (c). . (A) 60 to 100% by weight of a mixture of (meth) acrylic acid alkyl ester or (meth) acrylic acid alkyl ester and alkenylbenzenes, and an α, β-ethylenically unsaturated monomer copolymerizable therewith Body 0-40
The glass transition temperature obtained by polymerizing wt% is 35-80.
Aqueous dispersion of hydrophobic acrylic resin in the range of ° C. (B) Inorganic colloid sol (c) 0.0 based on 100 parts by weight of solid content of component (b)
1 to 30 parts by weight of water-soluble inorganic chlorine compound

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. 1. Polyethylene terephthalate film In the present invention, polyethylene terephthalate means not only polyethylene terephthalate / homopolymer but also copolymerized polyethylene terephthalate and ethylene terephthalate in which the repeating unit of ethylene terephthalate is 85% or more and the rest is other component It is 85% by weight or more and the remaining 15% by weight or less includes a polymer blend which is another polymer. Other polymers that can be blended include polyamides, polyolefins, and other types of polyesters. In this polyethylene terephthalate, if necessary, a lubricant, a colorant, which is usually added to polyethylene terephthalate,
Additives such as stabilizers and antioxidants can be added.

The polyethylene terephthalate film according to the present invention is stretched biaxially, but the magnification is
The width is preferably 2.0 to 5.0 times. If the stretching ratio is less than 2.0 times, the strength of the product will not be sufficient, which is not preferable. If the stretching ratio exceeds 5.0 times, the strength of the product will be sufficient, but the manufacturing work will be difficult. Therefore, it is not preferable. The stretching ratio is 2.5 to 4.0 in both biaxial directions.
A double range is particularly preferred. The method for producing the biaxially stretched film is not particularly limited and may be any conventionally known method such as sequential or simultaneous biaxial stretching.

The polyethylene terephthalate film according to the present invention preferably has a thickness of 0.01 to 0.3 mm. If the thickness is less than 0.01 mm, the strength of the product will not be sufficient, which is not preferable, and 0.3 m
If it exceeds m, the film becomes hard and difficult to handle, which is not preferable.

2. Acrylic Resin Coating The agricultural polyethylene terephthalate film according to the present invention has an acrylic resin coating formed by blending an ultraviolet absorber on one surface thereof. In the present invention, the acrylic resin is a vinyl-based resin which is mainly composed of a methacrylic acid alkyl ester monomer or a methacrylic acid alkyl ester monomer in the presence of a cross-linked acrylic acid ester-based elastic body and which is copolymerizable therewith. A graft copolymer obtained by polymerizing a mixture with a monomer and containing 5 to 80% by weight of a crosslinked acrylic acid ester-based elastic body is preferable. A crosslinked acrylate monomer is a polymer obtained by polymerizing a crosslinkable monomer and an alkyl (meth) acrylate monomer, or a vinyl monomer copolymerizable therewith. is there.

The crosslinkable monomer may be one that is usually used as a polyfunctional compound, and specific examples thereof include ethylene glycol dimethacrylate and 1,3-.
Butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, propylene glycol dimethacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, dipropylene glycol dimethacrylate, divinylbenzene, divinyl adipate, diallyl phthalate, diallyl maleate, Allyl acrylate, allyl methacrylate, triallyl cyanurate and the like,
These may be used in combination of two or more.

The (meth) acrylic acid alkyl ester monomer is an alkyl ester of acrylic acid or methacrylic acid, and specific examples thereof include methyl acrylate, ethyl acrylate, -n-propyl acrylate, Isopropyl acrylate, -n-butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid-
Examples thereof include n-propyl, isopropyl methacrylate, -n-butyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, and the like. Generally, an alkyl acrylate having an alkyl group having 1 to 20 carbon atoms and / Alternatively, a methacrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is used, and these may be used as a mixture.

Examples of vinyl monomers copolymerizable with these (meth) acrylic acid alkyl ester monomers include methacrylic acid and methacrylic acid alkyl esters (having 1 to 12 carbon atoms in the alkyl group) and itaconic acid dialkyl. Examples thereof include esters (alkyl groups having 1 to 10 carbon atoms), acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, styrene, nuclear alkyl-substituted styrene, and α-methylstyrene. These monomers are used in an amount of 40% by weight or less, preferably 25% by weight or less.

The crosslinked acrylic ester type elastic body is preferably produced by an emulsion polymerization method. The polymerization initiator that can be used at this time is a usual free radical generation initiator. Specific examples include inorganic peroxides such as potassium persulfate and ammonium persulfate; organic hydroperoxides such as cumene hydroperoxide, p-menthane hydroperoxide, ditertiary butyl hydroperoxide; benzoyl peroxide and lauroyl peroxide. Examples thereof include organic peroxides such as oxide and cumene peroxide, and azo initiators such as azobisisobutyronitrile.

Further, a conventional redox type initiator in which these are combined with a reducing agent such as sodium sulfite, sodium acid sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, glucose, polyamine and hydroxyacetone ascorbate is also used. sell.
Usable emulsifiers include ordinary surfactants for emulsion polymerization. For example, anionic surfactants such as sodium, potassium and ammonium salts of alkyl sulfates having 8 to 20 carbon atoms and sodium and potassium salts of aliphatic carboxylic acids such as lauric acid, stearic acid and palmitic acid, and alkylphenols And non-ionic surfactants such as aliphatic alcohols and reaction products of polypropylene oxides and ethylene oxide. In some cases, two or more of these surfactants can be used in combination. Further, a surfactant such as naphthaleneformaldecht condensed sulfonate may be added. If necessary, a cationic surfactant such as an alkylamine hydrochloride can be used.

Examples of the method for producing a crosslinked acrylic acid ester-based elastic body by the emulsion polymerization method include the following. (1) An emulsion polymerization method in which a small amount of a crosslinkable monomer is added to an acrylic acid alkyl ester monomer or a mixture of an acrylic acid alkyl ester monomer and a vinyl monomer copolymerizable therewith. How to manufacture by. (2) To the polymer emulsion obtained by the method of (1), an acrylic acid alkyl ester monomer or a mixture of an acrylic acid alkyl ester monomer and a vinyl monomer copolymerizable therewith is added. , A method for producing by an emulsion polymerization method. (3) The method of (2), wherein a small amount of a crosslinking agent is added to the monomer or the monomer mixture, and the mixture is produced by an emulsion polymerization method.

(4) First, an uncrosslinked polymer is prepared from an acrylic acid alkyl ester monomer or a mixture of an acrylic acid alkyl ester monomer and a vinyl monomer copolymerizable therewith by an emulsion polymerization method. To manufacture. Then, an acrylic acid alkyl ester monomer, or a mixture of an acrylic acid alkyl ester monomer and a vinyl-based monomer copolymerizable therewith, and a small amount of a crosslinkable monomer are added to the polymer. , A method for producing by an emulsion polymerization method. (5) To one of the polymer emulsions obtained by the methods of (1) to (4), an acrylic acid alkyl ester monomer or a vinyl monomer copolymerizable therewith is further added to form a crosslinkable monomer. A method of producing by an emulsion polymerization method with or without adding a body.

The crosslinked acrylic ester elastomer has an average particle diameter of the crosslinked elastic emulsion particles adjusted to 0.05 to 0.05 by adjusting the amount of the surfactant used and the amount of the aqueous medium used. The range is preferably 0.30 μm. If the thickness is less than 0.05 μm, the mechanical strength of the acrylic resin used as the coating film is reduced,
If it exceeds μm, stress whitening becomes remarkable, which is not preferable.
Further, the crosslinked acrylate-based elastic body preferably has a gel content of 80% or more and a swelling degree of 15 or less as measured by the following method.

A predetermined amount W _{0 of the} crosslinked elastic body was sampled, and the swollen weight W ₁ after being immersed in methyl ethyl ketone for 48 hours at room temperature and the weight W ₂ after drying this sample with a vacuum dryer were measured. Calculate by formula. Gel content _{= (W 2 / W 0)} × 100 (%) degree of swelling _{= (W 1 -W 2) /} W 0

The gel content and the degree of swelling are not limited to the above-mentioned adjustment of the type and amount of the cross-linkable monomer, but also the temperature at which the elastic body is polymerized, the type of the initiator and its amount used, and the unit constituting the elastic body. Since it is influenced by various polymerization conditions such as a method of adding a monomer and the presence / absence of a molecular weight modifier, it is preferable to appropriately adjust. When the gel content is less than 80%, the film-forming acrylic resin obtained from the elastic body is completely dissolved or excessively swelled in the organic solvent described below, and the elastic body particles are deformed, It is not preferable because it loses the function of improving mechanical strength, particularly impact resistance. Regarding the degree of swelling, if it exceeds 15, stress whitening tends to occur, which is not preferable.

The monomer to be grafted to the crosslinked acrylic acid ester-based elastic body is mainly composed of alkyl methacrylate or alkyl methacrylate.
It is a mixture with this and a vinyl-based monomer copolymerizable therewith.
The alkyl methacrylate ester as a component to be grafted may be selected from the above-mentioned ones used in the production of an elastic body, and a vinyl monomer copolymerizable therewith is also used in the production of an elastic body. May be selected from those exemplified above. In this case, the glass transition temperature (Tg) of the polymer or copolymer itself obtained from the monomer component to be grafted
It is preferable to select the type and combination of monomers so that the temperature is 50 ° C. or higher. If the Tg is less than 50 ° C., the polyethylene terephthalate film on which the acrylic resin film containing the graft polymer is formed has poor blocking resistance (is easily blocked), which is not preferable.

The graft polymerization reaction is preferably carried out by an emulsion polymerization method, but may also be carried out by a solution polymerization method. When the emulsion polymerization method is used, for example, a monomer to be grafted is added to the emulsion of the crosslinked acrylate-based elastic material, and if necessary, an emulsifier, a polymerization initiator, a molecular weight regulator,
Water and the like can be added to select and carry out ordinary emulsion polymerization conditions. The ratio of the crosslinked elastic body and the monomer to be grafted when performing the graft polymerization reaction is 10 to 90 parts by weight of the crosslinked elastic body emulsion as a polymer solid content, and 90 to 10 parts by weight of the grafted monomer. It is better to choose from a range.

The graft polymer can be used as it is or as an acrylic resin for forming a film by blending a transparent hard thermoplastic resin which is compatible with the graft polymer and has a Tg of 50 ° C. or higher. In the latter case, when blending, the proportion of the crosslinked elastic body contained in the acrylic resin is preferably in the range of 5 to 80% by weight, preferably 10 to 50% by weight. When the proportion of the crosslinked elastic body is less than 5% by weight, the mechanical strength is inferior, and when it exceeds 80% by weight, the film having this as a coating film has poor blocking resistance, which is not preferable. An ultraviolet absorber is mixed with these acrylic resins to form a coating on one surface of the base film.

Examples of the type of ultraviolet absorber include conventionally known ultraviolet absorbers such as salicylic acid compounds, cyanoacrylate compounds, benzophenone compounds and benzotriazole compounds. Among these, a benzophenone compound and / or a benzotriazole compound are preferable when evaluated from the viewpoints of solubility in an acrylic resin, weather resistance when applied to a polyethylene terephthalate film and used for agriculture.

The benzophenone compounds include 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone. , 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-
Hydroxy-4-benzoyloxybenzophenone,
2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfonebenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4' -Dimethoxybenzophenone, 2-hydroxy-5-chlorobenzophenone, bis- (2-methoxy-4-hydroxy-5-benzoylphenyl) methane and the like.

The benzotriazole type compounds include 2
-(2'-hydroxyphenyl) benzotriazole,
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5-methylphenyl) -5-carboxylic acid butyl ester benzotriazole, 2- (2'-hydroxy-5 ' -Methylphenyl) -5,6-dichlorobenzotriazole, 2-
(2'-hydroxy-5'-methylphenyl) -5-ethylsulfone benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy) -5′-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-5′-aminophenyl) benzotriazole,
2- (2'-hydroxy-3 ', 5'-dimethylphenyl) benzotriazole, 2- (2'-hydroxy-
3 ', 5'-dimethylphenyl) -5-methoxybenzotriazole, 2- (2'-methyl-4'-hydroxyphenyl) benzotriazole, 2- (2'-stearyloxy-3', 5'-dimethylphenyl ) -5-Methylbenzotriazole, 2- (2'-hydroxy-5-
Carboxylic acid phenyl) benzotriazole ethyl ester, 2- (2'-hydroxy-3'-methyl-5'-t
-Butylphenyl) benzotriazole, 2- (2'-
Hydroxy-3 ′, 5′-di-tert-butylphenyl)-
5-chlorobenzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-
Chlorobenzotriazole, 2- (2'-hydroxy-
5'-methoxyphenyl) benzotriazole, 2-
(2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-
Hydroxy-5'-cyclohexylphenyl) benzotriazole, 2- (2'-hydroxy-4 ', 5'-dimethylphenyl) -5-carboxylic acid benzotriazole butyl ester, 2- (2'-hydroxy-3', 5 '
-Dichlorophenyl) benzotriazole, 2- (2 '
-Hydroxy-4 ', 5'-dichlorophenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-
Dimethylphenyl) -5-ethylsulfone benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-methoxyphenyl) -5-methylbenzotriazole, 2- (2'-hydroxy-5'-methylphenyl) -5-carboxylic acid ester benzotriazole, 2
Examples include-(2'-acetoxy-5'-methylphenyl) benzotriazole and the like.

Furthermore, the benzophenone compounds and the benzotriazole compounds, polymers and polymers are also included. The amount of the ultraviolet absorber blended in the acrylic resin is too small, the object of the present invention is not achieved,
Too much can cause bleed-out problems. The preferred amount is 1 part by weight per 100 parts by weight of the acrylic resin.
It is in the range of 0 to 25 parts by weight. The thickness of the acrylic resin coating film containing these ultraviolet absorbers is 1 to 10 μm, and particularly preferably 1 to 5 μm. If it is less than 1 μm, the object of the present invention cannot be achieved, which is not preferable.
If it exceeds μm, there is a problem that the coating film is easily peeled off, which is not preferable.

The amount of the ultraviolet absorber compounded in the acrylic resin and the thickness of the film formed on one side of polyethylene terephthalate can be variously changed, but the amount of the ultraviolet absorber per fixed area of the film is 150 to 1000 mg. The range of / m ² is particularly preferable. In order to form a coating film of an acrylic resin containing an ultraviolet absorber on one surface of the agricultural polyethylene terephthalate film according to the present invention, first, biaxially stretched polyethylene terephthalate is produced. Then, on one side of the biaxially stretched polyethylene terephthalate film, one kind of ketones such as methyl ethyl ketone, aromatic hydrocarbons such as benzene, toluene and xylene, acetic acid esters such as methyl acetate and ethyl acetate, etc. Alternatively, a solution in which an acrylic resin and an ultraviolet absorber are dissolved is applied to an organic solvent that is a mixture of two or more kinds, and the organic solvent is volatilized by a method such as heating to form an acrylic resin coating containing the ultraviolet absorber. Good. As a coating method, a commonly used gravure coating method, a reverse coating method, a spray method, or the like is suitable.

3. Anti-Fogging Film The agricultural polyethylene terephthalate film according to the present invention is an anti-fogging film containing components (a) to (c) on the surface opposite to the surface coated with a film of an acrylic resin containing an ultraviolet absorber. The agent composition is applied. The hydrophobic acrylic resin which is the component (a) of the antifogging agent composition used in the present invention is at least a (meth) acrylic acid alkyl ester or a mixture of a (meth) acrylic acid alkyl ester and an alkenylbenzene. 60% by weight, and α, β-ethylenically unsaturated monomer copolymerizable therewith 0
The glass transition temperature obtained by polymerizing 40% by weight is 35
It is a hydrophobic acrylic resin in the range of -80 ° C.

The (meth) acrylic acid alkyl ester may be selected from those exemplified in 2 above. Examples of the alkenylbenzenes include styrene, α-methylstyrene, vinyltoluene and the like. When a mixture of alkenylbenzenes and (meth) acrylic acid alkyl esters is used, it is usually (meth) acrylic acid alkyl esters, although it varies depending on the amount of the α, β-ethylenically unsaturated monomer used. It is preferable to use 10% by weight or more, and it is preferable that the content of alkenylbenzenes in the hydrophobic acrylic resin is 70% by weight or less.

The hydrophobic acrylic resin used in the present invention is
Those containing at least 60% by weight of (meth) acrylic acid alkyl esters or a mixture of these and alkenylbenzenes are preferable, and when the amount is less than 60% by weight, the water resistance of the formed coating film is not sufficient, and The cloudiness persistence performance cannot be exhibited. Examples of the α, β-ethylenically unsaturated monomer copolymerizable with the (meth) acrylic acid alkyl esters or a mixture of the (meth) acrylic acid alkyl esters and the alkenylbenzenes include:
For example, α, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid
β-ethylenically unsaturated carboxylic acids; α, β-ethylenically unsaturated sulfonic acids such as ethylene sulfonic acid; 2
-Acrylamido-2-methylpropanoic acid; α, β-ethylenically unsaturated phosphonic acids; hydroxyl group-containing vinyl monomers such as hydroxyethyl of acrylic acid or methacrylic acid;
Acrylonitriles; acrylic amides; glycidyl esters of acrylic acid or methacrylic acid. These monomers may be used alone or in combination of two or more, and may be used in the range of 0 to 40% by weight. If it exceeds 40% by weight, the antifogging performance is deteriorated, which is not preferable.

As a method for polymerizing the hydrophobic acrylic resin from these monomers, various conventionally known emulsifiers such as anionic surfactants, cationic surfactants and nonionic surfactants are used. Method in the presence of one or more selected from agents, a method of emulsion polymerization in an aqueous medium, a method of polymerization using a reactive emulsifier, and a method of polymerization based on oligosoap theory without containing an emulsifier. Etc. In the case of the polymerization method in the presence of an emulsifier, these emulsifiers are added in an amount of 0.
It is used in the range of 1 to 10% by weight. Outside this range, it is difficult to control the polymerization rate, and the dispersion stability of the synthesized resin is poor.

Examples of the polymerization initiator used in the production of the hydrophobic acrylic resin include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides such as acetyl peroxide and benzoyl peroxide. To be These are 0.1 to the total amount of the charged monomers.
Used in the range of 10% by weight. The hydrophobic acrylic resin in the present invention has a glass transition temperature (Tg) of 35.
It must be in the range of -80 ° C. Such Tg can be obtained by selecting the type of monomer used and the amount (blending amount) used. If the Tg of the acrylic resin used exceeds 80 ° C., it is difficult to obtain a transparent and uniform coating film. When the Tg is less than 35 ° C., the inorganic colloid particles are easily aggregated several times to form a non-uniform dispersion state, and the inorganic colloid particles are not sufficiently fixed to the coating substrate. Colloidal particles fall off or flow off the surface of the base material, thereby impairing the antifogging performance.

Component (a) of the antifogging composition used in the present invention
The water-based emulsion of the hydrophobic acrylic resin is a water-based emulsion obtained by polymerizing each of the monomers in a water-based medium as it is, or a water-based emulsion further diluted with a liquid dispersion medium. Alternatively, a polymer produced by the above-mentioned polymerization may be separately collected and redispersed in a liquid dispersion medium to give an aqueous emulsion.

Examples of the inorganic colloid sol which is the component (b) of the antifogging agent composition used in the present invention include silica, alumina, water-insoluble lithium silicate, iron hydroxide, tin hydroxide, titanium oxide, barium sulfate and the like. An aqueous sol in which the inorganic aqueous colloidal particles are dispersed in water or a hydrophilic medium by various methods can be mentioned. Among them, silica sol and alumina sol are preferable. These may be used alone or in combination. The inorganic colloidal sol used has a solid average particle size of 5 to 100.
The range of mμ is preferable. Within this range, two or more types of colloid sols having different average particle sizes may be used in combination. If the average particle diameter exceeds 100 mμ, not only the coating film tends to be white and devitrified, but also the antifogging sustainability decreases, which is not preferable. If it is less than 5 μm, the stability of the inorganic colloid sol may be lacking.

The inorganic colloidal sol is preferably blended in a solid content weight ratio of 0.5 to 4 with respect to the acrylic resin. That is, when it is less than 0.5, a sufficient antifogging effect cannot be exhibited. Further, when it exceeds 4, not only the antifogging effect does not improve in proportion to the blending amount, but in the case of a transparent film, the coating film formed after coating becomes cloudy to reduce the light transmittance, and It is not preferable because the coating film is rough and easily becomes weak.

Examples of the water-soluble inorganic chlorine compound which is the component (c) of the antifogging agent composition used in the present invention include hydrogen chloride, ammonium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, barium chloride and chloride. Examples thereof include zinc, lithium chloride, aluminum chloride, ferrous chloride, ferric chloride, stannic chloride, mercuric chloride, sodium hypochlorite, potassium hypochlorite and calcium hypochlorite. Among these water-soluble inorganic chlorine compounds, monovalent chlorine compounds are particularly preferable. Also, these may be used in combination of two or more. The amount of the water-soluble inorganic chlorine compound added is 0.01 to 30 parts by weight based on 100 parts by weight of the solid content of the inorganic colloid sol, and particularly 0.01
˜20 parts by weight, preferably 0.01 to 10 parts by weight.

When the chlorine compound is a liquid, it means 100% by weight of the active ingredient. When the addition amount is less than 0.01 part by weight, it takes time to develop the antifogging property,
When the amount is more than the amount by weight, the inorganic colloid sol in the coating liquid aggregates, the transparency of the coating film decreases, and the antifogging property develops slowly, which is not preferable.

A cross-linking agent is preferably added to the antifogging composition prepared according to the present invention. The acrylic resin is cross-linked by the cross-linking agent, and the water resistance can be improved. Examples of the crosslinking agent include phenolic resins, amino resins, amine compounds, aziridine compounds, azo compounds, isocyanate compounds, epoxy compounds, silane compounds, and the like. Particularly, amine compounds,
Aziridine compounds and epoxy compounds are preferred.

The amine compounds include aliphatic polyamines such as diethylenetriamine, triethylenepentamine and hexamethylenediamine; 3,3'-dimethyl-4,
Alicyclic amines such as 4'-diaminodicyclohexylmethane and isophoronediamine; and aromatic amines such as 4,4'-diaminodiphenylmethane and m-phenylenediamine are used.

Examples of aziridine compounds include tris-
2,4,6- (1-aziridinyl) -1,3,5-triazine, trimethylolpropane-tri-β-aziridinylpropionate, tris [1- (2-methyl) aziridinyl] phosphine oxide, hexa [1- (2-Methyl) -aziridinyl] triphosphatriazine and the like are used.

Examples of the epoxy compounds include a reaction product of bisphenol A or phenol F and epichlorohydrin, an epoxidized novolac resin formed by a reaction of a resin reaction product of phenol (or a substituted phenol) with formaldehyde, and epichlorohydrin, and epichlorohydrin. And an aliphatic polyhydric alcohol such as glycerol, 1,4-butanediol, poly (oxypropylene) glycol or a resinous reaction product produced from a similar polyhydric alcohol component, and a resin obtained by epoxidation using peracetic acid, etc. Is used. In the case of epoxy compounds, it is preferable to use a tertiary amine or a quaternary ammonium salt in combination as a catalyst. These crosslinking agents can be used in an amount of 0.1 to 30% by weight based on the acrylic resin solid content. In particular, the range of 0.5 to 10% by weight is preferable.

The antifogging agent composition used in the present invention is usually used in liquid form. The liquid dispersion medium includes an affinity or water-miscible solvent containing water. Water: monohydric alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol: polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin: Cyclic alcohols such as benzyl alcohol: cellosolve acetates: ketones and the like. These may be used alone or in combination, but are determined in consideration of the dispersion stability of the antifogging agent composition used, the wettability after coating on the film surface, the difficulty of removing the liquid dispersion medium, and the economic efficiency. Is preferred.

The antifogging agent composition is generally prepared at a concentration of 0.5 to 50% by weight as a solid content of the hydrophobic acrylic resin and the inorganic colloid, and is usually prepared at a concentration of 1 to 20% by weight. Often diluted and used. The antifog composition prepared in the present invention may further contain an antifoaming agent,
Conventional additives such as plasticizers, film-forming aids, thickeners, pigments, pigment dispersants, light stabilizers, and ultraviolet absorbers can be mixed. Such an antifogging agent composition is applied to the surface of a polyethylene terephthalate film, forcedly dried or naturally dried, and a liquid dispersion medium is volatilized to form a coating film. As a method of forced drying, a hot air drying method, an infrared radiation method, or the like can be employed. The heating temperature at the time of forced drying is determined depending on the applied antifogging agent composition, but is 50 to 250.
C., preferably in the range of 70 to 200.degree.

As a coating method, a roll coating method,
Dip coating method, brush coating method, spray coating method,
-Coat method, knife coat method, etc.
It depends on the method. Antifogging agent composition on the surface of the film
After applying, drying and volatilizing the liquid dispersion medium
The amount applied is usually 0.01 to 10 g / m.^Two, Preferably 0.
1-5g / m ^TwoRange.

When the adhesion between the film surface and the coating film derived from the antifogging composition used in the present invention is not sufficient,
Before applying the antifogging composition, the film surface may be modified by plasma treatment or corona discharge treatment. When the agricultural polyethylene terephthalate film of the present invention is spread and used as an agricultural coating material, it is used so that the side provided with the antifogging film is the inside of a house or a tunnel.

[0049]

EFFECT OF THE INVENTION The agricultural polyethylene terephthalate film according to the present invention has a synergistic effect of an acrylic resin coating containing an ultraviolet absorber and a coating derived from an antifogging agent composition, thereby exhibiting an antifogging speed. And the effect of sustaining anti-fog are dramatically improved, so that it is extremely useful as a covering material for agriculture.

[0050]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments, but the present invention is not limited to the following examples unless it exceeds the gist. Examples 1 to 7 and Comparative Examples 1 to 7 (1) Substrate polyethylene terephthalate film Stretched 3.5 times in length and width, and has a density of 1.392.
g / cm ² and thickness of 150 μm. (2) Preparation of acrylic resin The acrylic resin solution for blending the ultraviolet absorber is
It was prepared as follows.

1) Preparation of Acrylic Resin Solution A Manufacture of Crosslinked Acrylic Ester Elastic Body 300 parts by weight of deionized water (hereinafter, simply referred to as “part” means “part by weight”) in a polymerization vessel. ), 0.3 part potassium persulfate, 0.5 part disodium phosphate dodecahydrate,
After charging 0.3 parts of sodium hydrogen phosphate dihydrate and sufficiently purging with nitrogen, the internal temperature was raised to 70 ° C. The internal temperature was maintained at this temperature, and 19.8 g of styrene was added with stirring.
, 69.3 parts of butyl acrylate, 0.9 parts of allyl methacrylate, and 2.5 parts of sodium dioctylsulfosuccinate (emulsifier) were continuously added over 2 hours. Immediately after the addition was completed, 1.0 part of t-butylperoxy-2-ethylhexanoate and 2.2 parts of styrene were used.
Parts, butyl acrylate 7.7 parts, allyl acrylate 0.
One part mixture was added. 30 minutes after the addition was completed, the internal temperature was raised to 90 ° C.
The reaction was continued for a time to obtain a crosslinked elastic emulsion. The average particle size of this crosslinked elastic body was 0.20 μm, the gel content was 97.1%, and the swelling degree was 7.2.

Production of Graft Copolymer A crosslinked elastomer emulsion 400 obtained above was placed in a polymerization vessel.
The mixture was purged with nitrogen while stirring, and then the internal temperature was raised to 80 ° C. While maintaining the internal temperature at this temperature, a solution of 0.15 parts of sodium formaldehyde sulfoxylate dissolved in 3.0 parts of deionized water was added with stirring, and then 30.0 parts of methyl methacrylate and n-octyl mercaptan were added. A mixture of 0.03 part and 0.15 part of paramenthane hydroperoxide (50% solution) was continuously added over 30 minutes. After completion of the addition, the polymerization reaction was continued for another 30 minutes to obtain a graft copolymer emulsion.
The glass transition temperature (Tg) of the copolymer itself obtained from the grafted monomer component was 108 ° C. The obtained graft copolymer emulsion was salted out according to a conventional method, and the polymer was separated by filtration, washed with water, and dried to obtain a graft copolymer powder.

Preparation of Resin Solution A 6.5 parts of the graft copolymer obtained above was mixed with methacrylic resin (methyl methacrylate / ethyl methacrylate 96 parts).
13.5 parts of (4/4 copolymer) beads are mixed,
This mixture was mixed with 64 parts of methyl ethyl ketone and 16 parts of toluene.
Put in a mixed solvent consisting of parts and dissolve with stirring,
An acrylic resin solution A having a solid content of 20% by weight was prepared.

2) Preparation of Acrylic Resin Solution B Manufacture of Crosslinked Acrylate Elastomer 250 parts of deionized water, 2.0 parts of sodium dioctylsulfosuccinate, 0.05 parts of sodium formaldehyde sulfoxylate were placed in a polymerization vessel. Was charged, and the atmosphere was sufficiently replaced with nitrogen. While stirring the contents of this polymerization vessel, 1.6 parts of methyl methacrylate, 8 parts of butyl acrylate, 1,3-
Butylenedimethacrylate 0.4 parts, allyl methacrylate 0.1 parts, cumene hydroperoxide 0.04
A mixture of parts was charged. The temperature inside the polymerization vessel was raised to 70 ° C., and the reaction was continued at this temperature for 60 minutes. Subsequently, 1.5 parts of methyl methacrylate, 22.5 parts of butyl acrylate, 1.0 part of 1,3-butylene methacrylate, 0.25 part of allyl methacrylate and a mixture of these monomers were added to the polymerization vessel. A mixture of 0.05% by weight of cumene hydroperoxide was added over 60 minutes. The obtained crosslinked elastic body has an average particle size of 0.1.
The gel content was 2 μm, the gel content was 90%, and the swelling degree was 10.

Production of Graft Copolymer A solution of 0.01 part of sodium formaldehyde sulfoxylate dissolved in 3 parts of deionized water was added to a polymerization vessel containing the above crosslinked elastic emulsion, and then 5 parts of methyl methacrylate was added. , Butyl acrylate 5 parts, allyl acrylate 0.1 parts and 0.03% by weight relative to these monomers
A mixture containing an amount of cumene hydroperoxide was added continuously over 30 minutes. After completion of the addition, the polymerization reaction was continued for another 30 minutes.

A solution prepared by dissolving 0.05 part of sodium formaldehyde sulfoxylate in 3 parts of ionic water was added to the polymerization vessel, and the temperature was raised to 80 ° C. to obtain 52.25 parts of methyl methacrylate and 2 parts of butyl acrylate. .75 parts, paramenthane hydroperoxide (50% solution) 0.13
A mixture of parts was added over 30 minutes. After completion of this addition, the polymerization reaction was continued at 80 ° C. for 30 minutes to obtain a graft copolymer emulsion. The glass transition temperature (Tg) of the copolymer itself obtained from the monomer component grafted on the outermost layer was 103 ° C. The obtained graft copolymer emulsion was salted out according to a conventional method, and the polymer was separated by filtration, washed with water, and dried to obtain a graft copolymer powder.

Preparation of Resin Solution B 20 parts of the graft copolymer obtained above was put into a mixed solvent of 64 parts of methyl ethyl ketone and 16 parts of toluene and stirred to obtain an acrylic resin solution having a solid content of 20% by weight. B was prepared.

(3) Formation of Coating Film Containing Ultraviolet Absorber In the acrylic resin solution prepared according to the method described in (2) above, the ultraviolet absorbent of the kind shown in Table 1 was added in the proportion ( It means the ratio to the resin solid content.). The solution after the addition was applied to one surface of a polyethylene terephthalate film by a gravure coating method, and the applied surface was heated to volatilize the solvent to form a film containing an ultraviolet absorber. Table 1 shows the thickness of this coating and the amount of the ultraviolet absorber per unit area of the film.

(4) Preparation of antifogging agent composition A four-necked flask was charged with 2 parts by weight of polyoxyethylene lauryl ether and 80 parts by weight of water, and heated to 60 ° C. under a nitrogen gas stream, and ammonium persulfate 0 0.5 part by weight was added, and 100 parts by weight of the mixture of each monomer shown in Table 1 was added dropwise over 3 hours. At this time, the reaction temperature was maintained in the range of 60 to 70 ° C., and after the completion of the dropwise addition, the temperature was maintained for 2 hours, followed by cooling to obtain an acrylic resin emulsion. The glass transition temperature of each resin is
It was as shown in Table-2. The acrylic resin emulsion thus obtained was mixed with the inorganic colloid sol in the types and amounts shown in Table 2 and the water-soluble inorganic chlorine compound and others to prepare various antifog compositions.

(5) Formation of coating film with antifogging agent composition On the opposite surface of the polyethylene terephthalate film obtained in (3) from the side provided with the acrylic coating, various antifogging agent compositions obtained in (4) The product was applied by a bar coating method so that the coating amount after drying was 0.5 g / m ² as a solid content, and the solvent was scattered by allowing it to stay in hot air at 80 ° C. for 1 minute.

(6) Evaluation of polyethylene terephthalate film Various properties of the polyethylene terephthalate film obtained in (5) were evaluated by the methods described below, and the results are shown in Table 3. Adhesiveness Cellophane tape was adhered to the surface of each film on which the antifogging coating was formed, and when the cellophane tape was peeled off, the state of peeling of the coating film was observed with the naked eye. The evaluation criteria are as follows. Good: The coating film did not peel off at all and remained completely. ◯ x: 2/3 or more of the coating film remained without peeling. Δ: 2/3 or more of the coating film peeled off. X: The coating film was completely peeled off.

Transparency The appearance of the film was visually observed. The evaluation criteria are as follows. ◯: Almost the same transparency as a film not coated with the antifogging composition. ◯ x: Some deterioration in transparency is recognized. B: Significant decrease in transparency is observed. X: The transparency is extremely deteriorated and cannot be put to practical use.

Anti-fogging property i) Condition 1 Above the water tank filled with water, the surface of the film on which the anti-fog coating film is formed is arranged facing the inside of the water tank, and the outside air temperature is 20 ° C.
Maintaining the temperature in the water tank at 50 ° C, 5 minutes and 10 minutes after placing the film on the upper part of the water tank,
The appearance speed of the antifogging property was visually observed and judged. Evaluation criteria are
It is as follows. ⊚: A state in which water adheres in a thin film and no water droplets are observed. ○: Water adhered in a thin film, but slightly large water droplets were observed. ○ x: Water adhered in a thin film, but large particles of water were partially adhered. Δ: A state in which fine water droplets are partially adhered. X: A state in which fine water droplets are observed to be attached to the entire inner surface of the film.

Ii) Condition 2 A single roof type house (2m in frontage, 20m in depth, 2m in ridge height, 30 roof slope) where the film was installed in an outdoor test field.
Degree), the surface provided with the anti-fog coating was applied to the inside of the house, and a spreading test was performed for 48 months from July H3 to June H7. During the spreading test, the antifogging property of each film was visually observed over time. This evaluation criterion is the same as in the case of the above condition 1. The results of these evaluations are shown in Table-3.

[0065]

[Table 1]

[0066]

[Table 2]

Note 1 in Table-1 X represents 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, Y represents 2- (2′-hydroxy-3 ′) , 5'-Ditertiarybutylphenyl) -5-chlorobenzotriazole Z represents 2,4-dihydroxybenzophenone, respectively. * 2 Glass transition temperature is a value calculated by the following formula. (1 / Tg) = (W ₁ / Tg ₁ ) + (W ₂ / Tg ₂ ) + ... + (W _n / Tg _n ) (wherein, Tg: glass transition temperature of hydrophobic acrylic resin (K ) Tg ₁ , Tg ₂ ··· Tg _n : glass transition temperature (K) W ₁ , W ₂ ··· W _{n of} each component 1, 2 ··· n: each component 1, 2 ··· n. The respective weight fractions of are shown.)

[0068]

[Table 3]

Note 2 in Table-2: The number of parts of the component (a) is the amount of polymer solids in the aqueous emulsion, the number of parts of the component (b) is the amount of inorganic particles, and the number of parts of the crosslinking agent is the solid content. Parts by weight are shown. * 2 Indicates the hydrogen chloride content in a 10% hydrogen chloride aqueous solution. * 3 Indicates the sodium hypochlorite content in a 5% sodium hypochlorite aqueous solution. * 4 Mutual Yakuko Co., Ltd. aziridine compound * 5 Dainippon Ink and Chemicals Inc. bisphenol A type epoxy compound

[0070]

[Table 4]

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08J 7/04 CFD C08J 7/04 CFDS C08K 3/00 C08K 3/00 C08L 25/02 KFV C08L 25/02 KFV 33/06 LHU 33/06 LHU 51/06 LKT 51/06 LKT C09D 125/02 PFB C09D 125/02 PFB 133/06 PGB 133/06 PGB 151/06 PGX 151/06 PGX (72) Inventor Kazuya Kinoshita 2 Oike, Iwazuka-cho, Nakamura-ku, Aichi Prefecture Nagoya, Mitsubishi Chemical MKV Co., Ltd. (72) Inventor, Shunichi Onishi 2 Oike, Iwazuka-cho, Nakamura-ku, Nagoya, Aichi Mitsubishi Chemical MKV Co., Ltd.

Claims (6)

[Claims] 1. A biaxially stretched polyethylene terephthalate film having a film made of an acrylic resin having a thickness of 1 to 10 μm formed by blending an ultraviolet absorber formed on one side, and the following components on the other side. A polyethylene terephthalate film for agricultural use, wherein a film derived from the antifogging agent composition containing (a) to (c) is formed. (A) 60 to 100% by weight of a mixture of (meth) acrylic acid alkyl ester or (meth) acrylic acid alkyl ester and alkenylbenzenes, and an α, β-ethylenically unsaturated monomer copolymerizable therewith Body 0-40
The glass transition temperature obtained by polymerizing wt% is 35-80.
Aqueous dispersion of hydrophobic acrylic resin in the range of ° C. (B) Inorganic colloid sol (c) 0.0 based on 100 parts by weight of solid content of component (b)
1 to 30 parts by weight of water-soluble inorganic chlorine compound 2. The agricultural polyethylene terephthalate film according to claim 1, wherein the antifogging agent composition contains a cross-linking agent for the hydrophobic acrylic resin as the component (a). 3. The agricultural polyethylene terephthalate film according to claim 1, wherein the ultraviolet absorber is a benzophenone compound and / or a benzotriazole compound, and the amount thereof is in the range of 150 to 1000 mg per 1 m ^{2 of the} film. 4. The ratio of the component (c) of the antifogging agent composition is 0.01 to 1 with respect to 100 parts by weight of the solid content of the component (b).
The polyethylene terephthalate film for agriculture according to any one of claims 1 to 3, which is 0 part by weight. 5. The blending amount of the component (b) of the antifogging agent composition is
The agricultural polyethylene terephthalate film according to any one of claims 1 to 4, which has a solid content weight ratio of 0.5 or more and 4 or less with respect to the component (a). 6. The acrylic resin of the coating film made of an acrylic resin is mainly composed of a methacrylic acid alkyl ester monomer or a methacrylic acid alkyl ester in the presence of a crosslinked acrylic acid ester elastic body, The agricultural polyethylene terephthalate film according to any one of claims 1 to 5, which is a graft copolymer obtained by polymerizing a mixture with a polymerizable vinyl-based monomer.