JP3204135B2 - Agricultural polyethylene terephthalate film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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. For this reason, polyethylene terephthalate films are widely used for magnetic tapes, photographic applications, electrical applications, metallizing applications, packaging applications, agricultural applications, 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 anti-fogging properties 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 these compositions contain a hydrophilic polymer such as polyvinyl alcohol or a hydroxyl group-containing acrylic resin for the purpose of imparting miscibility with the inorganic aqueous sol, the formed film tends to have essentially poor water resistance. is there. 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.

In order to improve the above disadvantages, for example, JP-A-55-99976 and JP-A-55-99987 disclose an inorganic-organic composite reaction comprising silica / hydrophilic polymer / organosilicon compound. There has been proposed a method for imparting anti-fogging property by using a material. However, these methods are also insufficient in water resistance and are not satisfactory in anti-fogging performance, and the intended purpose cannot be sufficiently achieved.

[0007]

In order to improve the above-mentioned drawbacks, for example, Japanese Patent Publication No. 4-57192 discloses
An anti-fogging film consisting of a hydrophobic acrylic resin and an inorganic colloid sol is formed on the surface, and a film that absorbs ultraviolet light is provided on the opposite surface. Attempts have been made to prevent this. However, according to this method, although the initial antifogging property is good, it is not enough to prevent the deterioration of the antifogging film with time due to long-term outdoor exposure, and it does not have stable antifogging durability. Was.

[0008]

Under such a background, the present inventors have shown that even when used for a long time, such as for covering a house, the mechanical strength does not decrease and excellent weather (light) resistance is exhibited. The present inventors have made intensive studies to provide an agricultural polyethylene terephthalate film having excellent anti-fogging properties that can be maintained for a long period of time. As a result, the present invention has been completed. The gist of the present invention is that an aqueous dispersion of a hydrophobic acrylic resin (a) having a glass transition temperature in the range of 35 to 80 ° C. is formed on one surface of a biaxially stretched polyethylene terephthalate film. A film derived from an antifogging agent composition containing an inorganic colloidal sol as a main component is formed, and an acrylic resin (b) having a thickness of 1 to 10 μm and a saturated polyester resin having an ultraviolet absorber mixed on the other side. (B)
Is formed, and the acrylic resin (b) is mixed with a methacrylic acid alkyl ester monomer or methacrylic acid in the presence of particles of a crosslinked acrylate-based elastic material (A). It contains a graft copolymer whose main component is an acid alkyl ester monomer and is obtained by polymerizing a mixture of a vinyl monomer and a copolymerizable vinyl monomer. And
The ratio of the elastic body (A) in the acrylic resin (B) is 5 to 5.
80% by weight, the ratio of the resin (B) in the thermoplastic resin is 1 to 50% by weight, and the weight ratio of (A) / (B) is 1
/ 1 to 20/1 in agricultural polyethylene terephthalate film.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polyethylene terephthalate referred to in the present invention is not only a polyethylene terephthalate homopolymer that has not been copolymerized, but also a copolymerized polyethylene in which 85% or more of the number of repeating units is composed of polyethylene terephthalate units and the remainder is other components. 85% by weight or more of terephthalate or polyethylene terephthalate, and the remaining 15% by weight or less contains a polymer blend which is another polymer. Other polymers that can be blended include polyamides, polyolefins, and other types of polyesters. A lubricant, a colorant, a stabilizer, an antioxidant, and the like can be added to the polyethylene phthalate as needed.

The agricultural polyethylene terephthalate film according to the present invention is biaxially stretched. The method for producing the biaxially stretched film is not particularly limited, and for example, a known method of sequentially or simultaneously biaxially stretching vertically and horizontally may be employed. The stretching ratio is preferably 2.0 to 5.0 times, especially 2.5 to 4.0 times, in the biaxial direction. If the draw ratio is less than 2.0 times, the strength of the product will not be sufficient, and it is not preferable. If the stretch ratio exceeds 5.0 times, the strength of the product will be sufficient, but the manufacturing operation is difficult. Is not preferred. The agricultural polyethylene terephthalate according to the present invention preferably has a thickness of 0.01 to 0.3 mm. When the thickness is less than 0.01 mm, the strength of the product is not sufficient, which is not preferable. When the thickness is more than 0.3 mm, the film becomes hard and difficult to handle, which is not preferable.

The agricultural polyethylene terephthalate film according to the present invention has on one surface thereof a film of a thermoplastic resin mainly composed of an acrylic resin (b) containing an ultraviolet absorbent and a saturated polyester resin. Become. In the present invention, the acrylic resin (b) is a vinyl methacrylate monomer or a methacrylate alkyl ester as a main component in the presence of a crosslinked acrylate-based elastic material, and a vinyl resin copolymerizable therewith. It contains a graft copolymer based on a crosslinked acrylate-based elastomer (A) obtained by polymerizing a mixture with a monomer.

The crosslinked acrylic ester-based elastic material 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 and ditertiary butyl hydroperoxide; benzoyl peroxide, lauroyl peroxide Examples thereof include organic peroxides such as oxide and cumene peroxide, and azo-based initiators such as azobisisobutyronitrile. In addition, these and sodium sulfite,
Sodium acid sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, glucose,
Conventional redox initiators in combination with reducing agents such as polyamines and hydroxyacetone ascorbic acid may also be used.

Examples of the emulsifier that can be used include ordinary surfactants for emulsion polymerization. For example, if the carbon number is 8
Sodium, potassium, ammonium salts of up to 20 alkyl sulfates and anionic surfactants such as sodium and potassium salts of aliphatic carboxylic acids such as lauric acid, stearic acid and palmitic acid; alkylphenols; aliphatic alcohols; Non-ionic surface activity such as a reaction product of polypropylene oxides and ethylene oxide can be mentioned. In some cases, two or more of these surfactants can be used in combination. Further, a surfactant such as a naphthalene formaldehyde condensed sulfonate may be added. If necessary, a cationic surfactant such as an alkylamine hydrochloride can be used.

The following method can be used to produce a crosslinked acrylate-based elastic material by an emulsion polymerization method. (1) A method in which a small amount of a crosslinkable monomer is added to a mixture of an alkyl acrylate monomer or a mixture of an alkyl acrylate and a vinyl monomer copolymerizable with the alkyl acrylate, followed by emulsion polymerization. . (2) An alkyl acrylate monomer or a mixture of an alkyl acrylate and a vinyl monomer copolymerizable therewith is further added to the polymer emulsion obtained by the method of (1), and the emulsion polymerization method is carried out. How to make. (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 elastic body is produced from an alkyl acrylate monomer or a mixture of an alkyl acrylate and a vinyl monomer copolymerizable therewith by an emulsion polymerization method. Next, an alkyl acrylate monomer, or a mixture of an alkyl acrylate and a vinyl monomer copolymerizable therewith, and a small amount of a crosslinkable monomer were further added to the polymerization system, followed by emulsion polymerization. How to manufacture by. (5) To one of the polymer emulsions obtained by the methods (1) to (4), an alkyl acrylate monomer or a vinyl monomer copolymerizable with the alkyl acrylate is further added and crosslinked. Without adding or adding a small amount of
A method produced by an emulsion polymerization method.

The average particle size of the crosslinked elastomer emulsion particles is adjusted by adjusting the amount of the surfactant and the amount of the aqueous medium to be used. It is important that the thickness be in the range of 0.30 μm. Below 0.05 μm, the mechanical strength of the acrylic resin used as a film decreases,
If it exceeds 0 μm, stress whitening becomes remarkable, which is not preferable. Regardless of the crosslinked acrylate-based elastic body produced by any of the above methods, it is preferable that the gel content measured by the following method is 80% or more and the degree of swelling is 15 or less.

A predetermined amount W _{0 of the} crosslinked elastic material was sampled, and the weight W ₁ swelled after immersion in methyl ethyl ketone for 48 hours at room temperature, and the weight W ₂ after drying the sample with a reduced pressure drier were measured. It is calculated by the formula. Gel content = (W ₂ / W ₀ ) × 100 (%) Swelling degree = (W ₁ −W ₂ ) / W _{0 The} gel content and swelling degree are not limited to the above-mentioned adjustment of the type and amount of the crosslinkable monomer. The temperature at which the elastic component is polymerized, the type and amount of the initiator used, the method of adding the monomer constituting the elastic component, and the polymerization conditions such as the presence or absence of a molecular weight regulator, are appropriately affected. It is better to adjust. Gel content is 8
When the amount is less than 0%, the acrylic resin for forming a film obtained from the elastic body is completely dissolved in an organic solvent described later, or swells excessively, and the elastic body particles are deformed.
As it loses its ability to improve mechanical strength, especially impact resistance,
Not preferred. Regarding the degree of swelling, if it exceeds 15, stress whitening tends to occur, which is not preferable.

The alkyl acrylate is preferably one having an alkyl group having 1 to 8 carbon atoms, and may be linear or branched. Specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, and the like, and these can be used in combination. Examples of the vinyl monomers copolymerizable with these alkyl acrylates include methacrylic acid and alkyl esters of methacrylic acid (alkyl groups having 1 to 12 carbon atoms) and dialkyl esters of itaconic acid (1 to 2 carbon atoms of alkyl groups). 10), acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, styrene, nucleus alkyl-substituted styrene, α-methylstyrene and the like. These monomers are used in an amount of 40% by weight or less, preferably 25% by weight or less.

As the crosslinkable monomer, those which are generally used as polyfunctional compounds may be used.
Ethylene glycol dimethacrylate, 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 may be mentioned, and two or more of these may be used in combination. The monomer to be grafted to the crosslinked acrylic ester-based elastic material is an alkyl methacrylate or an alkyl methacrylate as a main component, and is a mixture of a vinyl monomer and a copolymer thereof.

The alkyl methacrylate to be grafted preferably has 1 to 8 carbon atoms in the alkyl group, and may be linear or branched. Specific examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, and the like, and these can be used as a mixture. The vinyl monomer copolymerizable with the alkyl methacrylate is the same as the vinyl monomer copolymerizable with the alkyl acrylate, and the elastic material (A)
It may be selected from those exemplified as used in the production.

In this case, the polymer or copolymer obtained from the monomer component to be grafted itself has a glass transition temperature (T
It is important to select the type and combination of monomers so that g) is 50 ° C. or higher. If the Tg is less than 50 ° C., the polyethylene terephthalate film formed with a film containing the acrylic resin containing the graft polymer has poor blocking resistance (is easily blocked), which is not preferable. The graft polymerization reaction is preferably performed by an emulsion polymerization method, but may be performed by a solution polymerization method. When the emulsion polymerization method is used, for example, a monomer to be grafted is added to an emulsion of a crosslinked acrylate-based elastic material, and if necessary, an emulsifier, a polymerization initiator, a molecular weight regulator, water, etc. are added, and ordinary emulsification is performed. The polymerization conditions can be selected and carried out.

When performing the graft polymerization reaction, the ratio of the crosslinked elastomer to the monomer to be grafted is 10 to 90 parts by weight of the crosslinked elastomer as a polymer solid content, and 90 to 10 parts by weight of the grafted monomer. It is better to choose from a range of parts. The proportion of the elastic body (A) contained in the acrylic resin is from 5 to 80% by weight, preferably from 10 to 70%. When the proportion of the elastic body is less than 5% by weight, the mechanical strength is inferior, and when it exceeds 80% by weight, the film having the film as a film has poor blocking resistance, which is not preferable.

As the saturated polyester resin (B) used in the present invention, the acid component is mainly terephthalic acid,
In addition, adipic acid, azelaic acid, sebacic acid, phthalic acid, a dibasic acid such as isophthalic acid or an acid anhydride thereof and the like, the glycol component is mainly composed of ethylene glycol, and other 1,2-propanediol, 1,2-
A polymer composed of butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylhexanediol, etc., and having a molecular weight of 5,000 in Mw.
~ 50,000.

The proportion of the saturated polyester resin (B) contained in the film thermoplastic resin (hereinafter referred to as "film resin") is from 1 to 50% by weight, preferably from 5 to 30% by weight. Good. When the ratio of the saturated polyester resin (B) is less than 1% by weight, the adhesion of the formed film to the polyester film substrate is insufficient, and
If the content exceeds% by weight, it is not preferable because the weather resistance is poor. The mixing ratio of the elastic body (A) and the saturated polyester resin (B) in the acrylic resin (b) is 1/1 to 1 by weight.
It is in the range of 20/1. The weight ratio of (A) / (B) is 1 /
When it is less than 1, the mechanical strength is not sufficient, and
If it exceeds, the adhesion to the substrate is undesirably reduced.

The film resin composed of the acrylic resin (b) and the saturated polyester resin (B) is compatible with these and is a transparent thermoplastic resin having a Tg of 50 ° C. or more, for example, an epoxy resin, A urethane-based resin, a carbonate-based resin, or the like may be mixed. An ultraviolet absorber is blended with the above-mentioned film resin to form a film on one surface of the base film.

The type of the ultraviolet absorber to be incorporated into these film resins includes conventionally known ultraviolet absorbers such as salicylic acid compounds, cyanoacrylate compounds, benzophenone compounds, and benzotriazole compounds. Among these, ethyl-2-cyano-3,3 in the cyanoacrylate compound was evaluated from the viewpoints of solubility in the film resin, weather resistance when applied to a polyethylene terephthalate film, and used for agricultural purposes. -Diphenyl acrylate, 2,2 of benzophenone compounds
4-dihydroxy benzophenone, 2-hydroxy-
4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone are preferred,
Among the benzotriazole-based compounds, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole is particularly preferred. These may be used alone or in combination of two or more.

If the amount of the ultraviolet absorber incorporated in the film resin is too small, the object of the present invention will not be achieved,
Too much can cause bleed-out problems. The preferred amount is 10 to 2 parts by weight per 100 parts by weight of the coating resin.
The range is 5 parts by weight. The thickness of the thermoplastic resin film containing these ultraviolet absorbers is 1 to 10 μm,
If it is less than m, the object of the present invention will not be achieved, and if it exceeds 10 μm, there will be a problem that the film is easily peeled off. The amount of the UV absorber incorporated in the film resin and the thickness of the film formed on one side of polyethylene terephthalate can be variously changed.
It is particularly preferred to be in the range of 50 to 1000 mg / m ² .

In order to produce 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, ketones such as methyl ethyl ketone, benzene, toluene, aromatic hydrocarbons such as xylene,
A solution in which a film resin and an ultraviolet absorber are dissolved is applied to an organic solvent obtained by mixing one or two or more of acetates such as methyl acetate and ethyl acetate, and the organic solvent is volatilized. Form a plastic resin film.
The coating method is preferably a gravure coating method, a reverse coating method, a spray method, or the like, which is usually performed.

The agricultural polyethylene terephthalate film according to the present invention has an antifogging film formed on the opposite surface. The hydrophobic acrylic resin (A) in the antifogging agent composition used in the present invention has a glass transition temperature of 35 to 80.
Any temperature may be used as long as it is within the range of ° C, but a mixture of (meth) acrylic acid alkyl ester or (meth) acrylic acid alkyl ester and alkenylbenzene is 100 to 6%.
A homopolymer or a copolymer obtained by polymerizing 0% by weight and 0 to 40% by weight of an α, β-ethylenically unsaturated monomer copolymerizable therewith is preferred.

The alkyl (meth) acrylate is an alkyl ester of acrylic acid or methacrylic acid, and may be selected from those described above. Examples of alkenylbenzene include styrene, α-methylstyrene,
Vinyl toluene and the like. In the case of using a mixture of alkenylbenzene and alkyl (meth) acrylate, the ratio of the alkyl (meth) acrylate usually varies depending on the amount of the α, β-ethylenically unsaturated monomer used. Is preferably 10% by weight or more, and the alkenylbenzene contained in the hydrophobic acrylic resin in a range of 70% by weight or less is preferred.

The hydrophobic acrylic resin (A) used in the present invention contains at least 60% by weight of an alkyl (meth) acrylate or a mixture thereof with alkenylbenzene. If it is less than this, the water resistance of the formed film is not sufficient, which is not preferable.
Α, β copolymerizable with the alkyl (meth) acrylate or a mixture thereof with alkenylbenzene
-As the ethylenically unsaturated monomer, for example, α, β-ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid; Like α,
β-ethylenically unsaturated sulfonic acids; 2-acrylamido-2-methylpropanoic acid; α, β-ethylenically unsaturated phosphonic acids; hydroxyl-containing vinyl monomers such as hydroxyethyl of acrylic acid or methacrylic acid; acrylonitriles; Acrylic amides include glycidyl esters of acrylic acid or methacrylic acid. These monomers are
These may be used alone or in combination of two or more.
It can be used in the range of 0% by weight.

As a method of polymerizing the hydrophobic acrylic resin (a) from these monomers, various conventionally known emulsifiers such as anionic surfactants, cationic surfactants, and nonionic surfactants A method of emulsion polymerization in an aqueous medium in the presence of one or more selected from surfactants, a method of polymerizing using a reactive emulsifier,
It can be obtained by, for example, a method of polymerizing based on the oligosoap theory without containing an emulsifier. In the case of a polymerization method in the presence of an emulsifier, these emulsifiers are used in a range of 0.1 to 10% by weight based on the total amount of charged monomers. 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 for producing the hydrophobic acrylic resin (a) include persulfates such as ammonium persulfate and potassium persulfate, and organic peroxides such as acetyl peroxide and benzoyl peroxide. And the like. These are used in an amount of 0.1 to the total amount of the charged monomers.
It is used in the range of 1 to 10% by weight. The hydrophobic acrylic resin (A) of the present invention has a glass transition temperature (T
g) should be in the range of 35-80 ° C. Such Tg can be obtained by selecting the type of the monomer to be used and the amount to be used (blended amount). If the Tg of the acrylic resin used exceeds 80 ° C., it is difficult to obtain a transparent and uniform 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.

As the aqueous dispersion of the hydrophobic acrylic resin (a), which is a component of the antifogging agent composition of the present invention, an aqueous emulsion obtained by polymerizing each monomer in an aqueous medium is used as it is. Alternatively, a solution obtained by adding a liquid dispersion medium to the mixture and then diluting the mixture may be used.Also, a polymer produced by the above polymerization may be separately collected and redispersed in a liquid dispersion medium to obtain an aqueous dispersion. It may be something.

The inorganic colloid sol has a function of imparting unevenness to the surface of the polyethylene terephthalate film by coating the surface of the film with excellent surface smoothness. As the inorganic colloid sol, for example, silica, alumina, water-insoluble lithium silicate, iron hydroxide, tin hydroxide, titanium oxide, inorganic aqueous colloid particles such as barium sulfate, by various methods, dispersed in water or a hydrophilic medium. And an aqueous sol. Among them, silica sol and alumina sol are preferable. They are,
They may be used alone or in combination. The inorganic colloid sol used has a solid average particle diameter of 5 to 100 μm.
Are preferred. Within this range, two or more types of colloid sols having different average particle sizes may be used in combination. If the average particle size exceeds 100 μm, the film is devitrified white and the transparency is lowered, which is not preferable. Also,
If it is less than 5 μm, the stability of the inorganic colloid sol may be lacking.

The amount of the inorganic colloid sol is 0.5 to 4 based on the acrylic resin (a) in terms of the solid content weight ratio.
It is preferable to set the following. If less than 0.5,
The ability to prevent blocking cannot be fully demonstrated, and
If it exceeds 4, it is not preferable that the film is transparent because the film formed after application becomes cloudy and reduces the light transmittance, and the film becomes coarse and brittle.

It is preferable to add a crosslinking agent to the antifogging composition. Acrylic resins (a) are cross-linked by the cross-linking agent, and the film strength 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, etc. And epoxy compounds.

Examples of 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. 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.

Epoxy compounds include epoxidized novolak resins formed by the reaction of epichlorohydrin with the reaction product of bisphenol A or phenol F with epichlorohydrin, resin reaction products of phenol (or substituted phenol) with formaldehyde, epichlorohydrin And aliphatic polyhydric alcohols such as glycerol, 1,4-butanediol, poly (oxypropylene) glycol or similar polyhydric alcohol components, resinous reaction products, and resins 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 solid content of the acrylic resin (a). In particular, the range of 0.5 to 10% by weight is preferable. Thus, the antifogging agent composition is usually used in a liquid form. The liquid dispersion medium includes an affinity or water-miscible solvent containing water, and 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;

These may be used alone or in combination. However, they are determined in consideration of the dispersion stability of the composition to be used, the wettability after being applied to 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 (a) and the inorganic colloid, and is usually 1 to 20% by weight.
It is often prepared at a concentration of% by weight, and this is often used after dilution.

The antifogging agent composition prepared in the present invention may further contain, if necessary, a water-soluble inorganic chlorine compound, a defoamer, a plasticizer, a film-forming aid, a thickener, a pigment, a pigment dispersant and the like. Can be mixed. The antifogging film is formed by applying the composition on the surface of the film, forcibly drying or naturally drying, and evaporating the liquid dispersion medium.

As a method of forcibly drying, hot air drying,
An infrared radiation method or the like can be adopted. The heating temperature at the time of forced drying is determined by the applied anti-fogging agent composition, and is in the range of 50 to 250 ° C, preferably 70 to 200 ° C. The coating method may be any known method, and specifically, may be selected from those described above.

An antifogging composition is applied to the surface of the film,
Drying of the liquid dispersion medium, the adhesion amount of solids after volatilization,
Usually 0.01 to 10 g / m^Two, Preferably 0.1 to 5 g
/ M ^TwoRange. Film surface and used in the present invention
If the adhesion to the film derived from the antifogging agent composition is not sufficient
Before applying the composition,
Or a corona discharge treatment.
The surface of the film may be modified by a method. Of the present invention
Agricultural polyethylene terephthalate film
When used as a covering material, have an ultraviolet absorber
The side where the coating is provided is outside the house or tunnel.
It is used so that it becomes.

[0045]

The agricultural polyethylene terephthalate film according to the present invention is excellent in transparency and weather resistance, and
By having the antifogging film and the thermoplastic resin film containing an ultraviolet absorber, the excellent antifogging property is maintained for a long period of time, so that the value as an agricultural film is extremely large.

[0046]

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 9 and Comparative Examples 1 to 8 (1) Base polyethylene terephthalate film Each of the base and the base was stretched 3.5 times and the density was 1.392.
g / cm ³ and a thickness of 150 μm.

(2) Thermoplastic resin film Preparation of Thermoplastic Resin Solution (X, Y, Z, W _{1 to} W ₄ ) 1-1 Preparation of Coating Resin Solution X Preparation of Crosslinked Elastic Body 300 parts by weight of deionized water (hereinafter simply referred to as “parts”) Means "parts by weight"), 0.3 part of potassium persulfate, 0.5 part of 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 completion of the addition, 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. After 30 minutes from the end of the addition, the internal temperature was raised to 90 ° C.
The reaction was continued for an hour 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 degree of swelling was 7.2.

Production of Graft Copolymer The crosslinked elastic 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 prepared by dissolving 0.15 part of sodium formaldehyde sulfoxylate in 3.0 parts of deionized water was added with stirring, and then 30.0 parts of methyl methacrylate and n-octyl were added. A mixture of 0.03 parts of mercaptan and 0.15 parts 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 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 powder of the graft copolymer (a).

Preparation of Resin Solution X To 6.5 parts of the graft copolymer (a) obtained above, a methacrylic resin (methyl methacrylate / ethyl methacrylate was added to 9 parts)
11.5 parts of beads of the copolymer (b) and a saturated polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.)
(Molecular weight: 15,000 to 20,000)), and this mixture was placed in a mixed solvent of 64 parts of methyl ethyl ketone and 16 parts of toluene and dissolved with stirring to give a solid content of 20% by weight. % Resin solution X was prepared.

1-2 Preparation of Coating Resin Solution Y 5.0 parts of the graft copolymer (a) obtained in 1-1 was mixed with 10.0 parts of methacrylic resin (b) beads and a saturated polyester resin (Toyobo Co., Ltd.) Byron 103 (molecular weight 18,0)
5.0 to 20,000)), and this mixture was placed in a mixed solvent of 64 parts of methyl ethyl ketone and 16 parts of toluene and dissolved with stirring to give a solid content of 2 parts.
A resin solution Y of 0% by weight was prepared.

1-3 Preparation of Film Resin Solution Z Production of Crosslinked Elastic Material In a polymerization vessel, 250 parts of deionized water, 2.0 parts of sodium dioctylsulfosuccinate and 0.05 part of sodium formaldehyde sulfoxylate were charged. Sufficient nitrogen substitution was performed. While stirring the contents of the polymerization vessel, 1.6 parts of methyl methacrylate, 8 parts of butyl acrylate,
0.4 part of 3-butylene methacrylate, 0.1 part of allyl methacrylate, cumene hydroperoxide 0.1 part.
A mixture consisting of 04 parts was charged. 70 ℃ inside the polymerization can
, 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 had an average particle diameter of 0.12 μm, a gel content of 90%, and a swelling degree of 10.

Preparation of Graft Copolymer A solution prepared by dissolving 0.01 part of sodium formaldehyde sulfoxylate in 3 parts of ionic water was added to the polymerization vessel containing the crosslinked elastic emulsion described above, and then methyl methacrylate was added. 5 parts, 5 parts of butyl acrylate, 0.1 part of allyl acrylate, and a mixture obtained by adding cumene hydroperoxide in an amount of 0.03% by weight to these monomers is required for 30 minutes, and continuously. Was added. 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 butyl acrylate. 2.75 parts, paramenthane hydroperoxide (50% solution) 0.1
The mixture of 3 parts was added over 30 minutes. After completion of the addition, the polymerization reaction was continued at 80 ° C. for 30 minutes to obtain a graft copolymer emulsion. 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 powder of the graft copolymer (c).

Preparation of Resin Solution Z 15 parts of the graft copolymer obtained above and a saturated polyester resin (Vylon 103 (manufactured by Toyobo Co., Ltd., molecular weight: 18,00)
0 to 20,000)) was placed in a mixed solvent of 64 parts of methyl ethyl ketone and 16 parts of toluene and stirred to prepare a resin solution Z having a solid content of 20% by weight.

1-4 6.5 parts of the graft copolymer (a) obtained from the resin solution W1-1-1 were mixed with 13.5 parts of beads of the same methacrylic resin (b), and the mixture was mixed with 64 parts of methyl ethyl ketone. It was put into a mixed solvent consisting of 16 parts of toluene and dissolved with stirring to prepare a resin solution W1 having a solid content of 20% by weight. 1-5 2.0 parts of the graft copolymer (a) obtained from the resin solution W2 1-1, 17.0 parts of beads (b) and 1 part of Byron 200 were mixed, and the mixture was mixed with 64 parts of methyl ethyl ketone. It was put into a mixed solvent consisting of 16 parts of toluene and dissolved with stirring to prepare a resin solution W2 having a solid content of 20% by weight.

1-6 Resin Solution W3 11.5 parts of the methacrylic resin (b) beads and 8.5 parts of Byron 103 were mixed, and the mixture was placed in a mixed solvent consisting of 64 parts of methyl ethyl ketone and 16 parts of toluene. Then, the mixture was dissolved with stirring to prepare a resin solution W3 having a solid content of 20% by weight. 1-7 Resin solution W4 5 parts of the graft copolymer (c) and 1 part of Byron 103
Five parts were mixed, and this mixture was placed in a mixed solvent consisting of 64 parts of methyl ethyl ketone and 16 parts of toluene and dissolved with stirring to prepare a resin solution W4 having a solid content of 20% by weight.

2. Formation of film containing ultraviolet absorber Above 1. The UV absorbers of the type shown in Table 1 were added to the resin solution prepared according to the method described in (1) at the ratios (meaning the ratios to the resin solids) shown in the table. Each solution after the addition was applied to one surface of a polyethylene terephthalate film by a gravure coating method, and the coated surface was heated to evaporate the solvent to form a film containing an ultraviolet absorber. Table 1 shows the thickness of the film and the amount of the ultraviolet absorber per unit area of the film. In the film of Comparative Example 2, an ultraviolet absorber was blended in the base film.

(3) Anti-fog coating Preparation of Acrylic Resins (A to F) In a four-necked flask, 2 parts by weight of polyoxyethylene lauryl ether and 80 parts by weight of water were charged and heated to 60 ° C. under a stream of nitrogen gas, and 0.5 parts by weight of ammonium persulfate was added thereto. Was added, and a mixture 1 of each monomer shown in Table 2 was added.
00 parts by weight were 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 as shown in Table 2 and is a value calculated by the following equation.

[0060]

[Number 1] (1 / Tg) = (W 1 / Tg 1) + (W 2 / T
_{g 2) + ... + (W} n / Tg n) ( wherein, Tg: Glass transition temperature of the hydrophobic acrylic resin _{(k) Tg 1, Tg 2} ... Tg n: the homopolymer of the respective components 1, 2 ... n glass transition temperature _{(k) W 1, W 2} ... W n: respectively denote the weight fraction of each component 1, 2 ... n).

[0061] 2. Formation of antifogging film The types and amounts of inorganic colloid sols and others shown in Table 3 were blended with the acrylic resin emulsion obtained in the above to prepare an antifogging agent composition. On the surface opposite to the surface on which the film of the polyethylene terephthalate film obtained in (2) was formed, the amount of each antifogging agent composition after drying was 0.5 g / m ² as a solid content by a bar coating method. It was then applied and kept in hot air at 80 ° C. for 1 minute to disperse the solvent.

(4) Evaluation of polyethylene terephthalate film Various properties of the polyethylene terephthalate film obtained in (3) were evaluated by the methods described below. The results are shown in Table 3. 1. Adhesion of antifogging film A cellophane tape was adhered to the surface of each film on which the antifogging film was formed, and when the cellophane tape was peeled off, the peeling state of the film was visually observed. The evaluation criteria are as follows. ；: Completely left without peeling of the coating film. Ｘx: 2/3 or more of the coating film remained without peeling. Δ: One-third or more of the coating film was peeled off. ×: The coating film was completely peeled.

2. Anti-fog test A single-roof anti-fog test tank (frontage 1m, depth 5m, ridge height 1.3m, roof slope 30 °) with each film installed in a test field in Nagoya city , And the antifogging property was periodically evaluated with the naked eye. The evaluation criteria are as follows. : Water adhered in a thin film form, but slightly large water droplets were observed. Ｘx: a state in which water adheres in a thin film form, but adhesion of large water droplets is partially observed. Δ: A state in which fine water droplets are partially adhered. X: Fine water droplets adhered to the entire inner surface of the film.

[0064]

[Table 1]

[0065]

[Table 2]

[0066]

[Table 3]

* 1 Shows the amount of polymer solids in the aqueous emulsion * 2 Shows the amount of inorganic particles * 3 Aziridine-based compound manufactured by Mutual Pharmaceutical Co., Ltd. * 4 Bisphenol A type epoxy compound manufactured by Dainippon Ink Co., Ltd.

Continuing on the front page (72) Takashi Takasawa, 2 Oike, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi Prefecture Mitsubishi Chemical MKV Corporation Nagoya Office (72) Atsushi Obayashi 2-Oike, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi (56) References JP-A-60-178049 (JP, A) JP-A-8-58044 (JP, A) JP-A-63-153134 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 A01G 9/14 A01G 13/02

Claims (5)

(57) [Claims] 1. A biaxially stretched polyethylene terephthalate film having a glass transition temperature of 35 to
A film derived from an aqueous dispersion of a hydrophobic acrylic resin (a) in the range of 80 ° C. and an anti-fogging agent composition containing an inorganic colloid sol as a main component is formed, and an ultraviolet absorber is compounded on the other surface. And a thermoplastic resin film having a thickness of 1 to 10 [mu] m and containing a saturated polyester resin (B) as a main component, and the acrylic resin (B) is a crosslinked acrylic acid ester. An alkyl methacrylate monomer in the presence of particles of the system elastic body (A),
Or a methacrylic acid alkyl ester monomer as a main component, a graft copolymer obtained by polymerizing a mixture with a copolymerizable vinyl monomer and a cross-linked acrylate-based elastic material as a trunk. The proportion of the elastic body (A) in the acrylic resin (b) is 5 to 80% by weight, the proportion of the resin (B) in the thermoplastic resin is 1 to 50% by weight, The weight ratio of (A) / (B) is 1/1 to 20 /
1. An agricultural polyethylene terephthalate film which is 1. 2. The composition according to claim 1, wherein the ultraviolet absorbent is incorporated in an amount of 10 to 25 parts by weight based on 100 parts by weight of the thermoplastic resin.
The agricultural polyethylene terephthalate film described in the above. 3. The agricultural polyethylene terephthalate film according to claim 1, wherein the saturated polyester resin is a polymer having terephthalic acid as a main acid component and ethylene glycol as a main glycol component. 4. The hydrophobic acrylic resin (a) is 100 to 60% by weight of an alkyl (meth) acrylate or a mixture of an alkyl (meth) acrylate and alkenylbenzene, and is copolymerizable therewith. α,
The agricultural polyethylene terephthalate film according to any one of claims 1 to 3, which is a homopolymer or a copolymer obtained by polymerizing 0 to 40% by weight of a β-ethylenically unsaturated monomer. 5. The agricultural polyethylene terephthalate film according to claim 1, wherein the solid average particle of the inorganic colloid sol in the antifogging agent composition is 5 to 100 μm.