JP3204129B2 - 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 and excellent weather resistance (light resistance) and capable of withstanding long-term outdoor expansion.

[0002]

2. Description of the Related Art In general, polyethylene terephthalate films exhibit high crystallinity and high melting point, exhibit heat resistance and chemical resistance, and exhibit excellent mechanical properties such as strength and elastic modulus. Although it is known, this film has a property of absorbing ultraviolet rays, and particularly has a property of strongly absorbing ultraviolet rays of 320 nm or less. When this film is extended outdoors for a long time, its mechanical properties are significantly reduced. There are drawbacks. In order to improve the weather resistance of this film, a method of tightly bonding an ultraviolet absorber to the film surface as described in JP-B-46-24160 is known. According to this method, although the weather resistance is improved, it is difficult to firmly bond the ultraviolet absorber to the film surface at a uniform concentration, and the weather resistance is sufficiently imparted to long-term outdoor expansion and outdoor exposure. It was difficult to do.

[0003] In such a situation, the present inventors,
In order to provide an agricultural polyethylene terephthalate film that does not lose its mechanical properties even if it is extended or exposed outdoors for a long period of time, the present inventors have intensively studied and completed the present invention (Jpn. issue). The agricultural polyethylene terephthalate film according to the present invention has excellent weather resistance, and has a very small decrease in mechanical strength, transparency and the like even when exposed outdoors for a long period of time. By the way, when a plastic film for agriculture is spread in a house (greenhouse) or tunnel, the method of spreading, the structure of the house or tunnel,
The film may be bent or be blown by the wind depending on the location, direction, weather conditions at the time of extension, and the like where these are installed. In such a case, a film is formed on the surface of the plastic film, and if the film has poor elasticity and impact resistance, cracks are easily generated in the film. If cracks occur in the film, it may cause apparent whitening of the film, or the film may be peeled off, causing a practical problem.

[0004] In order to improve the impact resistance of a film made of an acrylic resin, the proportion of a component for improving the flexibility of the acrylic resin such as an acrylate ester is increased, and the glass transition temperature ( It is experimentally known that Tg) should be lowered. However, if the Tg is too low, there is a problem that blocking (adhering to each other) of the films easily occurs, and it is difficult to balance impact resistance and blocking resistance. In view of such a situation, the present inventors have found that the film does not whiten or peel even under severe conditions at the time of stretching, and has excellent mechanical strength and excellent weather resistance (light resistance). Then, as a result of intensive studies to provide an agricultural polyethylene terephthalate film that can withstand long-term outdoor expansion, the present invention was completed.

However, the gist of the present invention is as follows.
One side of the biaxially stretched polyethylene terephthalate film has a thickness of 1 to which an ultraviolet absorber is blended.
A thermoplastic resin film mainly composed of a 10 μm acrylic resin and a saturated polyester resin (B) is formed, and the acrylic resin is formed in the presence of particles of a crosslinked acrylic ester elastic material (A). A methacrylic acid alkyl ester monomer, or a methacrylic acid alkyl ester monomer as a main component, obtained by polymerizing a mixture of a vinyl monomer and a copolymerizable vinyl monomer, a cross-linked acrylic ester-based elastic body It contains a graft copolymer as a backbone, the proportion of the elastic body (A) in the acrylic resin is 5 to 80% by weight, and the proportion of the resin (B) in the thermoplastic resin is 1 to 5% by weight.
0% by weight, and the weight ratio of (A) / (B) is 1/1 to 2
0/1, which is a polyethylene terephthalate film for agricultural use characterized by being 0/1.

[0006]

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 thermoplastic resin film mainly composed of an acrylic resin and a saturated polyester resin mixed with an ultraviolet absorber. In the present invention, the acrylic resin, in the presence of a crosslinked acrylic ester-based elastic body, a methacrylic acid alkyl ester monomer, or a methacrylic acid alkyl ester as a main component,
It contains a graft copolymer having a backbone of a crosslinked acrylic acid ester-based elastic material (A) obtained by polymerizing a mixture of this with a copolymerizable vinyl 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.

[0010] Usable emulsifiers include the usual 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 to adjust the average particle diameter of the crosslinked acrylate-based elastic particles. 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 an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, 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 usually 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.

The ratio of the crosslinked elastomer to the monomer to be grafted during the graft polymerization reaction may be 10 to 90 parts by weight of the crosslinked elastomer as a polymer solid content, and 90 to 10 parts by weight of the monomer to be grafted. 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 1 to 50% by weight, preferably 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 is 1/1 to 20 / by weight.
1 range. If the weight ratio of (A) / (B) is less than 1/1, the mechanical strength is not sufficient, and if it exceeds 20/1, the adhesion to the substrate is undesirably reduced.

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

As the type of the ultraviolet absorber to be incorporated in these film resins, conventionally known ultraviolet absorbers, for example, salicylic acid compounds, cyanoacrylate compounds, benzophenone compounds, benzotriazole compounds and the like can be mentioned. 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.

When the agricultural polyethylene terephthalate film according to the present invention is stretched and used in a house, it may be stretched so that the side in contact with sunlight (outside the house) is the surface on which the film is formed. On the other hand, depending on conditions such as the temperature and humidity in the house, fogging may occur on the inner surface of the house of the film. It is preferable to form a hydrophilic film, an organic hydrophilic film, and the like.

[0027]

The agricultural polyethylene terephthalate film according to the present invention has the following effects, and its industrial utility value is extremely large. Agricultural polyethylene terephthalate film according to the present invention, even if extended or exposed outdoors for a long time, without being affected by ultraviolet rays, without having small cracks on the surface,
It does not turn yellow or whiten. The effect of preventing the deterioration of the weather resistance and the transparency is extremely remarkable as compared with the method of forming a film by adding another ultraviolet absorber. Further, the polyethylene terephthalate film according to the present invention has a thermoplastic resin film formed on one side, which contains a crosslinked elastic body and a saturated polyester resin, and has excellent adhesion, mechanical strength, and particularly excellent impact resistance. Therefore, cracks are unlikely to occur even when subjected to an impact, so that whitening of the film and peeling of the film due to the cracks do not easily occur.

[0028]

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 4 to 7 (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) Preparation of Thermoplastic Resin A thermoplastic resin solution for blending an ultraviolet absorber was prepared as follows. 1 Preparation of Coating Resin Solution X Production of Crosslinked Elastic Body In a polymerization vessel, 300 parts by weight of deionized water (hereinafter, simply referred to as “parts” means “parts by weight”), potassium persulfate 0.1 parts by weight. 3 parts, disodium phosphate dodecahydrate 0.5 part,
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. 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 In a polymerization vessel, the crosslinked elastic emulsion 400 obtained above was added.
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
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.

2 Preparation of Coating Resin Solution Y 5.0 parts of the graft copolymer (a) obtained in 1 was added to 10.0 parts of beads of methacrylic resin (b) and saturated polyester resin (Vylon 103 (manufactured by Toyobo Co., Ltd.) Molecular weight 18,000
5.0 parts), 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 obtain a resin solution Y having a solid content of 20% by weight. Was prepared.

3 Preparation of Coating Resin Solution Z Preparation of Crosslinked Elastic Material In a polymerization vessel, 250 parts of deionized water, 2.0 parts of sodium dioctylsulfosuccinate, and 0.05 parts of sodium formaldehyde sulfoxylate were charged, and nitrogen was sufficiently added. A substitution was made. 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.

Production 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 elastomer 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., and 52.25 parts of methyl methacrylate and butyl acrylate were added. 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.

4 6.5 parts of the graft copolymer (a) obtained from the resin solution W11 was 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 and 16 parts of toluene. Into a mixed solvent consisting of
A resin solution W1 of 0% by weight was prepared. 5 2.0 parts of the graft copolymer (a) obtained with the resin solution W21, 17.0 parts of the beads (b), and 1 part of Byron 200 were mixed, and the mixture was mixed with 64 parts of methyl ethyl ketone and 16 parts of toluene. Into a mixed solvent, and dissolved with stirring to prepare a resin solution W2 having a solid content of 20% by weight.

6 Resin Solution W3 11.5 parts of the beads of the methacrylic resin (b) 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. The resin solution W3 was dissolved with stirring to prepare a resin solution W3 having a solid content of 20% by weight. 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.

(3) Formation of UV Absorber-Containing Film The resin solution prepared according to the method described in (2) above,
The ultraviolet absorbers of the type shown in Table 1 were added at the ratios shown in the table (meaning the ratios to the resin solids). The 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.

(4) Evaluation of Film The performance of each of the obtained polyethylene terephthalate films was evaluated by the following methods, and the results are shown in Table 1. Properties of the film before outdoor exposure (a) Light transmittance at a wavelength of 340 nm Measured with a spectrophotometer (type 323 manufactured by Hitachi, Ltd.). (B) Puncture impact strength A puncture impact tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.) tests a sample having a length of 10 cm and a width of 10 cm,
Energy at the time of destruction expressed in kg · cm.

(C) Visual judgment of transparency The transparency of the film was visually observed and judged. The criteria for the judgment were as follows. ：: excellent in transparency, with no whitened portion observed on the surface. △ to △: excellent in transparency, with almost no whitened portion on the surface. Δ: Transparency was slightly inferior, and a whitened portion was slightly observed on the surface. Δ to ×: Transparency is extremely poor, and a whitened portion is considerably observed on the surface. ×: Transparency is extremely poor, and a whitened portion is remarkably observed on the surface.

(D) Adhesive strength of the film A cellophane tape (made by Nichiban) was adhered to the polyethylene terephthalate film, and the change in the film after the cellophane tape was peeled off was visually judged. The criteria for the judgment were as follows. ◎: Even if the pasted cellophane tape is vigorously peeled off,
No change is observed in the film. ：: When the attached cellophane tape is vigorously peeled off, a very small amount of the film accompanies the cellophane tape, but when the film is slowly peeled off, no change is observed in the film. Δ: A large amount of the film is accompanied by the cellophane tape regardless of the momentum when the attached cellophane tape is peeled off, and a remarkable change in the film is observed.

Properties of Film after Outdoor Exposure Each of the obtained polyethylene terephthalate films was exposed in a field in Aichi Prefecture from November, 1994 to October, 1996. Properties were measured over time. The puncture impact strength and the visual judgment of the transparency are the same as those in the method for evaluating the properties of the film before outdoor exposure.

Comparative Example 1 A film was formed on a base polyethylene terephthalate film having the same properties as that used in Example 1 and a film was not formed.
The results are shown in Table 1. Comparative Example 2 A film of a resin solution X containing no ultraviolet absorber was formed on one surface of a base polyethylene terephthalate film having the same properties as those used in Example 1. This film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 100 parts by weight of the raw material polyethylene terephthalate was mixed with 2-
0.34 parts by weight of (2′-hydroxy-5′-tert-butylphenyl) benzotriazole was blended. This composition was formed into a film by a known method, stretched 3.5 times in each of length and width, and had a density of 1.392 g / c.
A film having a thickness of m ³ and a thickness of 150 μm was obtained. This film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

* 1 The types of ultraviolet absorbers are as follows. a ... 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole b ... 2,4-dihydroxybenzophenone c ... 2-hydroxy-4-methoxybenzophenone

──────────────────────────────────────────────────続 き Continuing on the front page (72) Takashi Takasawa 2nd Oike, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Nagoya Mitsubishi Chemical MKV Corporation Nagoya Office Address Mitsubishi Chemical MKV Corporation Nagoya Office (56) References JP-A-60-178049 (JP, A) JP-A-8-58044 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) B32B 1/00-35/00 A01G 9/14 A01G 13/02

Claims (3)

(57) [Claims] 1. A thermosetting resin comprising a 1 to 10 μm thick acrylic resin and a saturated polyester resin (B) obtained by blending an ultraviolet absorber on one side of a biaxially stretched polyethylene terephthalate film. A plastic resin film is formed, and the acrylic resin contains, as a main component, an alkyl methacrylate monomer or an alkyl methacrylate monomer in the presence of particles of the crosslinked acrylate-based elastic body (A). And a graft copolymer obtained by polymerizing a mixture of this and a copolymerizable vinyl monomer, containing a graft copolymer having a crosslinked acrylate-based elastic body as a backbone. The proportion of the elastic body (A) is 5 to 80% by weight, the proportion of the resin (B) in the thermoplastic resin is 1 to 50% by weight, and the weight ratio of (A) / (B) is 1/1. ~ 20/1 Agricultural polyethylene terephthalate film, characterized in that there. 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.