JPS60178049A - Agricultural polyethylene terephthalate film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyethylene terephthalate films for agricultural use. More specifically, the present invention relates to an agricultural polyethylene terephthalate film that has excellent mechanical strength and excellent weather resistance (light resistance) and can withstand long-term outdoor expansion.

In general, polyethylene terephthalate films are known to exhibit high crystallinity, high melting point, heat resistance, chemical resistance, and excellent mechanical properties such as strength and elastic modulus. For this reason, polyethylene terephthalate films are widely used for magnetic tapes, photography, electricity, metallization, packaging, agriculture, and the like. However, this film has the property of absorbing ultraviolet rays, particularly ultraviolet rays of 320 nm or less, and has the disadvantage that when this film is extended outdoors for a long period of time, its mechanical properties deteriorate significantly.

In order to improve the weather resistance of this film, the film was made after adding an ultraviolet absorber.
As described in the '1-IAO publication, a method of tightly bonding an ultraviolet absorber to a film surface is known. In the former method, the ultraviolet absorber is uniformly mixed and dispersed in the resin.

However, according to this method, when harmful light rays pass through the film, they are gradually absorbed and weakened as they move from the incident side to the opposite side, but the side of the film where the light rays are incident is not harmed by the harmful rays. Therefore, the scratch resistance of the film cannot be sufficiently improved. Although the latter method can produce a film with better weather resistance than the former method, it is difficult to firmly bond the UV absorber to the film surface at a uniform concentration.
11 which is sufficient for long-term outdoor deployment and outdoor exposure.
It was a great blessing to give it a weather-like quality.

Under these circumstances, the inventors of the present invention have made extensive studies in order to provide an agricultural polyethylene terephthalate film whose mechanical properties do not deteriorate even if it is exposed to heat or exposed outdoors for a long period of time. He then completed the idea (Utility Model Publication No. 139.2.39, 1982). The agricultural polyethylene terephthalate film according to this invention has excellent weather resistance, and even when exposed outdoors for a long period of time, there is very little decrease in mechanical strength, 5 degrees, transparency, etc.

By the way, when spreading agricultural plastic film in greenhouses or tunnels, there are some differences depending on the method of spreading, the structure of the greenhouse or tunnel, the location and direction in which these are installed, the weather conditions at the time of spreading, etc. The film may be folded or blown away by the wind. In such a case,
A film is formed on the surface of a plastic film, and if this film has poor elasticity and impact resistance, cracks are likely to occur in the film. When cracks occur in the film,
This may cause apparent whitening of the film or peeling of the film, causing practical problems.

In order to improve the impact resistance of a film made of acrylic resin, increase the proportion of a component that improves the flexibility of the acrylic resin, such as disotyl acrylate, and increase the glass transition temperature (T) of the resin. , 51) has been found experimentally to be lower. However, if the TI is made too low, the blocking (mutual adhesion) of this skin will occur.
The problem arises that this tends to occur, and it is difficult to balance impact resistance and blocking resistance.

In view of this situation, the present inventors have developed a film that does not cause whitening or peeling of the film even under harsh conditions during spreading, and has excellent mechanical strength and excellent weather resistance (light resistance). However, as a result of intensive studies to provide an agricultural polyethylene terephthalate film that can withstand long-term outdoor expansion, the present invention has been completed.

Therefore, the gist of the present invention is that the thickness is 0.0 times the thickness of
/ ~ 0.311 agricultural polyethylene terephthalate film, on one side of which is formed an acrylic resin film with a thickness of 7 to 70 microns, which is blended with an ultraviolet absorber, and this acrylic resin is cross-linked. Obtained by polymerizing a methacrylic acid alkyl ester monomer or a mixture of a methacrylic acid alkyl ester as a main component and a vinyl compound monomer copolymerizable with it in the presence of acrylic ester-based elastomer particles. The present invention relates to an agricultural polyethylene terephthalate film, which is a graft copolymer and contains the crosslinked acrylic ester elastomer in an amount by weight of s-go.

The present invention will be explained in detail below.

The polyethylene terephthalate referred to in the present invention includes not only uncopolymerized polyethylene terephthalate homopolymers, but also polyethylene terephthalate homopolymers in which 5% or more of the repeating units are polyethylene terephthalate units, and the remainder is other components. Polymerized polyethylene terephthalate, polyethylene terephthalate gS weight ratio or more, and the remaining /! Includes polymer blends that are other polymers with less than i mass ton. Other polymers that can be blended include polyamides, polyolefins, and other types of polyesters. This polyethylene terephthalate may be blended with a lubricant, a colorant, a stabilizer, an antioxidant, etc., if necessary.

The agricultural polyethylene terephthalate film according to the present invention is biaxially stretched.

The method for producing a biaxially stretched film is not particularly limited, and for example, a known method of sequentially or simultaneously stretching the film in the vertical and horizontal directions may be employed.

Agricultural polyethylene terephthalate that relates to the present invention is
The film was stretched by 3.0 times (U) and (Q) in the biaxial directions, respectively. If the stretching ratio is less than 2.0 times, the strength of the product will not be sufficient, which is undesirable.If the stretching ratio exceeds S or O times, the strength of the product will be sufficient, but the manufacturing This is not preferable because it becomes difficult. The stretching ratios are λ and h-z9. A range of θ times is particularly preferred.

The agricultural polyethylene terephthalate according to the present invention preferably has a thickness of 0.0/% 0.3 mm.

If the thickness is less than 0.0 mm, the strength of the product will not be sufficient, which is undesirable, and if it exceeds 0.0 m, the film will become hard and difficult to handle, which is undesirable.

The agricultural polyethylene terephthalate film according to the present invention has an acrylic resin film containing an ultraviolet absorber formed on one side thereof.

In the present invention, the acrylic resin refers to a methacrylic acid alkyl ester monomer or a vinyl compound monomer copolymerizable with the methacrylic acid alkyl ester as a main component in the presence of a crosslinked acrylic ester elastomer. It refers to a graft copolymer obtained by polymerizing a mixture of the above-mentioned crosslinked acrylic acid ester-based elastic material and which engages the crosslinked acrylic acid ester elastic material by 5 to θ weight.

The acrylic acid alkyl ester preferably has an alkyl group having 7 to 7 g of carbon atoms, and may be either linear or branched. Specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, -λ-ethylhexyl acrylate, and octyl acrylate, and these can also be used in combination.

Vinyl compound monomers that can be copolymerized with these acrylic acid alkyl esters include methacrylic acid and mono-olkyl esters of methacrylic acid (alkyl group having 7 to 7 carbon atoms).
．． '2), itaconic acid nosialkyl ester (alkyl group carbon number 1 to tO), acrylonitrile, methacrylaterile, vinyl chloride, vinylidene chloride, styrene, nuclear alkyl-substituted styrene, α-methylstyrene, and the like. These monomers have a weight coefficient of less than 20% by weight, preferably 2
! It is preferable to set it to below rMm%.

As the crosslinkable monohydrogen, those commonly used as polyfunctional compounds may be used, and a specific example is ethylene glycol dimethacrylate.

/, 3-butylene glycol dimethacrylate, /, l
I-Butylene glycol dimethacrylate.

Propylene glycol dimethacrylate, trimethylolpropane trimethacrylate, tetramethylolmethanetetramethacrylate, dipropylene glycol dimethacrylate, divinylbenzene, divinyl adipate, diallyl phthalate, diallyl maleate, allyl acrylate, allyl methacrylate, triallyl cyanurate, etc. , these may be used in combination of two or more types.

The crosslinked acrylic ester-based elastomer is preferably manufactured by emulsion polymerization.

Polymerization initiators that can be used in this case are common free radical generating initiators. Specific examples include inorganic peroxides such as potassium persulfate and ammonium persulfate; organic nohydrocarbon oxides such as cumene hydroperoxide, p-menthane hydroperoxide, and ditertiary butyl hydroperoxide; benzoyl rhenochloride oxide; Examples include organic peroxides such as lauroyl peroxide and cumenochloride oxide, and azo initiators such as agebisisobutyronitrile.

In addition, these are combined with reducing agents such as sodium sulfite, acidic sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, glucose, polyamine, and hydroxyacetone ascorbate.
Conventional redox initiators can also be used.

Emulsifiers that can be used include common surfactants for emulsion polymerization. For example, anionic surfactants such as sodium, potassium, ammonium salts of alkyl sulfates with g -, 20 carbon atoms and aliphatic salts such as lauric acid, stearic acid, and valmitic acid. and nonionic surfactants such as alkylphenols, aliphatic alcohols, and reaction products of polypropylene oxide and ethylene oxide. Further, in some cases, two or more of these surfactants can be used in combination. Furthermore, surfactant auxiliaries such as naphthalene formaldehyde condensed sulfonate salts can also be added. Furthermore, if necessary, cationic surfactants such as alkylamine hydrochlorides can also be used.

The following method can be used to produce a crosslinked acrylic ester elastomer by emulsion polymerization.

(1) Adding a small amount of a crosslinkable monomer to an acrylic acid alkyl ester monomer or a mixture of an acrylic acid alkyl ester and a vinyl compound monomer copolymerizable therewith,
A method of manufacturing by emulsion polymerization method.

t2+ Produced by an emulsion polymerization method by adding an acrylic acid alkyl ester monomer or a mixture of an acrylic acid alkyl ester and a vinyl compound monomer copolymerizable therewith to the polymer emulsion obtained by the method of t2+ (1). Method.

(31 (In the method of 21, a method of manufacturing by adding a small amount of crosslinking agent to the monomer or monomer mixture and using an emulsion polymerization method.

(4) An uncrosslinked elastic body is produced by an emulsion polymerization method from a mixture of mass, an acrylic acid alkyl ester, or an acrylic acid alkyl ester and a vinyl compound monomer copolymerizable therewith. Next, an Acrylic acid alkyl ester monomer, or a mixture of an acrylic acid alkyl ester and a vinyl compound monomer copolymerizable therewith, and a small amount of a crosslinking monomer are then added to this polymerization system. By adding an acrylic acid alkyl ester monomer or a vinyl compound monomer copolymerizable with an acrylic acid alkyl ester to the process produced by the emulsion polymerization method, and adding no or a small amount of a crosslinking monomer, emulsion polymerization is performed. How to manufacture by law.

The average particle diameter of the crosslinked acrylic ester emulsion particles is adjusted by adjusting the amount of the surfactant and the amount of the aqueous medium used. It is important that the range is from OS to 0.3θ microns.

o. If the os micrometer is less than 7, the mechanical strength of the acrylic resin used as the coating will decrease, and if it exceeds 0.30 micron, stress whitening will not be noticeable, which is not preferable.

The crosslinked acrylic ester elastomer, regardless of which method is manufactured above, should have a gel content of gθ% or more and a swelling/circumference of 15 or less as measured by the following method. .

A predetermined amount W of the crosslinked elastic body. The swollen weight W1 after sampling and immersing the sample in methyl ethyl ketone for 73 hours at room temperature and the weight W after drying this sample in a vacuum dryer are measured and calculated using the following formula.

W.

Gel content--g　X　/θ0(person) Swelling degree -225 W.

In addition to adjusting the type and size of the crosslinkable monomer mentioned above, the gel content and degree of swelling are determined by the temperature when polymerizing the elastomer component, the type and amount of initiator used, and the amount of monomers constituting the elastomer component. Since it is affected by the method of addition of the polymer and the conditions of polymerization of the molecular weight regulator, it is best to adjust the conditions accordingly. When the gel kondo is less than the gO ratio, the film-forming acrylic resin obtained from the elastic body will be completely dissolved in the organic solvent described below or will swell excessively, causing the elastic particles to deform. , which is undesirable because it loses its ability to improve mechanical strength, especially impact resistance. Regarding the degree of swelling, if it exceeds is, stress whitening tends to occur, which is not preferable.

The 14 monomer to be grafted onto the crosslinked acrylic ester elastic body is a mixture of a methacrylic acid alkyl ester or a methacrylic acid alkyl ester as a main component, and a vinyl compound q4'f:ij compound which can be copolymerized with the methacrylic acid alkyl ester. .

Methacrylic acid ester as a component to be grafted is
You may choose from the above-mentioned materials used in the production of elastic bodies,
There are also vinyl compound monomers that can be copolymerized with this! , and may be selected from those exemplified as being used in the production of elastic bodies.

In this case, the glass transition temperature (Tg) of the polymer or copolymer obtained from the monomer components to be grafted is
It is important to select the type and combination of monomers so that the temperature is at least SO°C. When the TI is less than 50°C, the blocking resistance of the polyethylene terephthalate film formed with the acrylic resin film containing the graft polymer deteriorates (it is susceptible to blocking), which is not preferable.

The graft polymerization reaction is preferably carried out by emulsion polymerization, but may also be carried out by solution polymerization.

When using the emulsion polymerization method, for example, a monomer to be grafted is added to an emulsion of a crosslinked acrylic acid ester elastic group, and if necessary, an emulsifier, a polymerization initiator, a molecular weight regulator, water, etc. are added, and the usual emulsification is carried out. Polymerization conditions can be selected and carried out.

When carrying out the graft polymerization reaction, the ratio of the crosslinked elastic body to the monomer to be grafted is as follows: the crosslinked elastic body emulsion is the solid content of the polymer/Q~90 weight, and the monomer to be grafted is ``yo-ioi''. It is best to choose from a range of parts.

The graft polymer can be used as it is, or by blending it with a transparent hard thermoplastic resin that is compatible with the graft polymer and has a TI of 50° C. or higher, it can be used as an acrylic resin for film formation. In the latter case, when blending, the proportion of the crosslinked elastic body contained in the acrylic resin is 3-g O1jJj -F1j'%, preferably /θ~! ; Should be in the range of 0%. If the proportion of the crosslinked elastic body is less than the S weight factor, the mechanical strength will be poor, and if it exceeds 30% by weight, the primary blocking property of the film containing it as a coating will be poor, which is not preferable.

The acrylic resin is blended with an ultraviolet absorber to form a film on one side of the base film.

The types of ultraviolet absorbers added to these acrylic resins include conventionally known ultraviolet absorbers such as salicylic acid compounds, cyanoacrylate compounds, benzophenone compounds, and benzotriazole compounds.

Among these, when evaluated from the viewpoints of solubility in acrylic resins, weather resistance when applied to polyethylene-y-phthalate film for agricultural use, etc., ethyl-λ of cyanoacrylate compounds -Cyanor 3.3
- diphenyl acrylate, s, dihydroquine benzophenone, co-hydroxy-methoxybenzophenone, 2.
'-dihydroxy-q-methoxybenzophenone,
−′-dihydroxy-p,+′-dimethoxybenzophenone is preferred, and λ among benzotriazole compounds
-(,2'-hydroxy-y-tert-butylphenyl)benzotriazole is particularly preferred.

These may be used alone or in combination of two or more.

The amount of ultraviolet absorber blended into the acrylic resin is:
If it is too small, the object of the present invention will not be achieved, and if it is too large, there will be a problem of bleed-out. The preferred blending amount is 10- parts by weight of the acrylic resin.
The range is 25 parts by weight.

The thickness of the acrylic resin film containing these ultraviolet absorbers is not preferable because if it is too thin, the object of the present invention will not be achieved, and if it is too thick, a problem arises in that the film is likely to peel off.

The thickness of the film is preferably in the range of 1 to /Qμ, especially / to
A range of Sμ is preferred.

The amount of UV absorber blended into the acrylic resin and the thickness of the film formed on one side of the polyethylene terephthalate can be varied, but the amount of UV absorber per fixed area of the film is.

A range of ~/o, o mg7 tri is particularly preferred.

To produce the agricultural polyethylene terephthalate film according to the present invention, first, biaxially stretched polyethylene terephthalate is produced.

Next, one side of the biaxially stretched polyethylene terephthalate film is coated with ketones such as methyl ethyl ketone, aromatic hydrocarbons such as benzene, toluene, and xylene, and acetate esters such as methyl acetate and ethyl acetate. A solution containing an acrylic resin and an ultraviolet absorber dissolved in one or more organic solvents is applied, and the organic solvent is evaporated to form a diacrylic resin film containing an ultraviolet absorber. Suitable coating methods include commonly used gravure coating methods, reverse coating methods, spray methods, and the like.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a cross-sectional view of an example of the agricultural polyethylene terephthalate film according to the present invention, and FIG. 2 is a cross-sectional view of the film according to the present invention when sunlight hits the film from the side where the acrylic resin film is provided. Figure 3 is a schematic diagram showing the transmission of ultraviolet rays when sunlight is applied to a conventional polyethylene terephthalate film in which UV absorbers are uniformly dispersed throughout the film. FIG.

In the figure, / and 2/ indicate a polyethylene terephthalate film, 22 and 22 indicate a polyethylene terephthalate film containing an ultraviolet absorber, respectively.

The agricultural polyethylene terephthalate film according to the present invention has an acrylic resin film containing an ultraviolet absorber formed on one side thereof. When this film is used for actual agricultural purposes, it is used with the acrylic resin coating on the outside so that sunlight hits this side. When used in this manner, as schematically shown in FIG.
It is made to have a strength of 1000 ft, and this strength allows it to pass through a polyethylene terephthalate film. On the other hand, with the conventional film made by kneading an ultraviolet absorber into the film, as shown schematically in Figure 3, the ultraviolet rays hitting the film with an intensity of lin are transmitted through the film. is gradually absorbed,
Jout's strength is used. Such a difference in the absorption state of ultraviolet rays has a great influence on the weather resistance of the film.

The agricultural polyethylene terephthalate film according to the present invention has the following effects and has extremely great industrial utility value.

■ When the agricultural polyethylene terephthalate film according to the present invention is spread outdoors, the absorption of ultraviolet rays in sunlight d1 is different from that shown in Fig. 1 when it is kneaded with an ultraviolet absorber as shown in Fig. 3. As such, most of the water is absorbed and dispersed by the film made of acrylic resin.

This allows polyethylene terephthalate film to
Even if it is expanded or exposed outdoors for a long time, it will not be affected by ultraviolet rays, will not develop small cracks on its surface, and will not turn yellow or turn white. The effect of preventing deterioration in weather resistance and transparency is extremely significant compared to methods in which other ultraviolet absorbers are added to form a film, or methods in which the ultraviolet absorber is tightly bonded to the film surface.

■ The polyethylene terephthalate film according to the present invention has a film made of acrylic resin formed on one side, which contains a crosslinked elastic material and has excellent mechanical strength, especially impact resistance, so it can withstand impact. Cracks are less likely to occur, and therefore, whitening of the film and peeling of the film due to cracks are less likely to occur.

(2) The polyethylene terephthalate film according to the present invention has excellent adhesion to the film made of acrylic resin formed on one side, and combined with the fact that this film is extremely thin, the film does not peel off.

(1;) Compared to other resins, the Acrylic IJ resin formed on one side of the polyethylene terephthalate film has fewer bleed-out problems even if it contains a large amount of UV absorber, and Suitable for forming a film containing an absorbent.

■ The film made of acrylic resin formed on one side of the polyethylene terephthalate film according to the present invention has excellent weather resistance, so it is not easily deteriorated by ultraviolet rays and does not have any adverse effect on the base polyethylene terephthalate film. .

■ Due to its characteristics, the film made of acrylic resin is non-sticky and does not attract much dust, which contributes to maintaining transparency and transmittance for a long period of time, so the film according to the present invention is suitable for agricultural applications. It is.

Hereinafter, the present invention will be explained in detail based on examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example/~10 (17 polyethylene terephthalate films were stretched 3.3 times in length and width, and the density was /, 392 g/c
d, thickness is /, 25μ.

(2) Preparation of acrylic resin An acrylic resin solution for blending an ultraviolet absorber was prepared as follows.

l) Preparation of acrylic resin solution A ■ Production of cross-linked elastic body In a tin can, add 300 parts by weight of deionized water (under 9, "parts" simply means "parts by weight"), 0.3 part of potassium persulfate, 0.5 part of disodium phosphate dodecahydrate, and 0.3 part of sodium hydrogen phosphate λ hydrate were charged, and after sufficient nitrogen substitution, the internal temperature was raised to 70°C. . While maintaining the internal temperature at this temperature and stirring, add styrene/9. g part, 69.3 parts of butyl acrylate, 0.9 parts of allyl methacrylate, and 2.5 parts of sodium dioctyl sulfosuccinate (emulsifier).
It was added continuously over time.

Immediately after the addition was completed, a mixture consisting of 0 parts of t-butyl-oxysuethylhexanoate, 2.2 parts of methylene chloride, 7.7 parts of butyl acrylate, and 0.1 part of allyl acrylate was added. After 30 minutes had passed since the addition was completed, the internal temperature was raised to 90°C, and the reaction was continued at this temperature for 3 hours to obtain an emulsion with crosslinked elasticity.

The average particle diameter of this crosslinked elastic body was 0.20 microns, the gel content was 97.7%, and the degree of swelling was 7.2.

(2) Production of graft copolymer A polymerization vessel was charged with yoo parts of the crosslinked elastomer emulsion obtained in (1) above, and while stirring, the atmosphere was replaced with nitrogen, and the internal temperature was raised to goC. Maintain the internal temperature at this temperature and add 3.0 parts of deionized water while stirring) IJ
Umformaldehyde sulfoquine L/ -1-0,l
After adding the solution containing part S, add methyl methacrylate 3
θ, 0 parts, n-octyl mercaptan 0.03 parts, paramenthane hydroperoxide (30% solution) 0, /
! Part i of the mixture was added continuously over a period of 30 minutes. After the addition was completed, the polymerization reaction was continued for another 30 minutes to obtain a single graft copolymer emulsion.

The obtained graft copolymer emulsion was salted out according to a conventional method, and the polymer was separated by η, washed with water, and dried to obtain a graft copolymer powder.

■ 6.5 parts of the graft copolymer obtained in the preparation of resin solution A was mixed with 3.3 parts of beads of methacrylic resin (copolymer of methyl methacrylate/ethyl methacrylate at a ratio of 96/g). and then dissolve it while stirring until the solid content is 20 tons 'rjj'
% of acrylic resin bath solution A was prepared.

Preparation of acrylic resin solution B ■ Production of crosslinked elastic body Into a polymerization vessel, charge XSO parts of deionized water, 6 parts of sodium dioctyl sulfosuccinate, o and o s parts of sodium formaldehyde sulfoxylate, and add enough nitrogen. I made a replacement. While stirring the contents of this polymerization, add 6 parts of methyl methacrylate, 3 parts of butyl acrylate, and 0.0 parts of 3-butylene dimethacrylate. +
! A mixture consisting of 0.1 part of allyl methacrylate, and o and q parts of cumene hydroperoxide was charged.

The polymerization internal temperature was raised to 70°C, and the reaction was continued at this temperature for 1.0 minutes. Subsequently, for this polymerization, 7.3 parts of methyl methacrylate, 1.6 parts of butyl acrylate λ,sm,/,3-butylene dimethacrylate, 0.25 parts of allyl methacrylate, and a mixture of these monomers were added. O, O!
A mixture of cumene hydroperoxide in an amount of i weight was added over a period of 60 minutes.

The obtained crosslinked elastic body had an average particle diameter of 0,172 microns, a gel content of 90%, and a swelling degree of IO.

■ To the polymerization containing the crosslinked elastomer emulsion described in (■) in the production of a graft copolymer, a solution of 0.0 part of sodium formaldehyde sulfoxylate dissolved in 3 parts of ionic water is added, and then methyl methacrylate is added. A mixture of S part, butyl acrylate part S, 0.1 part of allyl acrylate, and cumene hydroperoxide in an amount of 0.0.3 dihedrons per these monomers was added continuously for 30 minutes. added. After the addition was completed, the polymerization reaction was continued for an additional 30 minutes.

To this polymerization, a solution containing 3 parts of ionized water and 3 parts of IJ formaldehyde sulfoxylate was added, and the temperature was raised to 0°C, and methyl methacrylate!
;, 2.23 parts, butyl acrylate 2.73 parts, paramenthane hydroperoxide (30% solution) 0. 3 parts of the mixture were added over 30 minutes. After this addition was completed, 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 into 1 pieces, washed with water, and dried to obtain a graft copolymer powder.

■ Add 2.0 parts of the graft copolymer obtained in the preparation of resin solution B to a mixed solvent of 6 parts of methyl ethyl ketone and 76 parts of toluene and stir. A system resin solution B was prepared.

3) Preparation of acrylic resin solution C ■ Manufacture of crosslinked elastic body In the preparation of acrylic resin solution B Same as in case of ■.

■ Production of graft copolymer In the case of preparation of acrylic resin solution B■ A graft copolymer powder was obtained in the same manner as above.

70 parts of this graft copolymer powder and 787,750 parts of methyl ethyl were placed in a tin can, stirred to dissolve the copolymer, and 3 parts of methyl methacrylate was added to the copolymer.
0 parts and to benzoyl peroxide. The mixture was then thoroughly purged with nitrogen, and the temperature was raised to 70°C with stirring, and the polymerization reaction was carried out at this temperature for 3 hours.

(2) Preparation of 171 fat solution C To the solution of the graft copolymer obtained above, 70 parts of methyl ethyl ketone and go parts of toluene were added to prepare an acrylic resin solution C having a resin solid content of 10 parts by weight.

Preparation of acrylic resin solution ■ Production of crosslinked elastic body After 200 parts of deionized water and a and o parts of sodium dioctyl sulfosuccinate were charged into a polymerization reactor, the reactor was sufficiently purged with nitrogen. Add butyl acrylate, 2 parts, and methyl methacrylate to this polymerization can. A mixture consisting of 0.3 parts of tetraethylene glycol diacrylate and 0.3 parts of cumene hydroperoxide θ was charged, and the mixture was stirred under a stream of nitrogen gas. The temperature was raised to ℃. Then, sodium formaldehyde sulfoxylate (θ,/wt% relative to the monomer mixture) dissolved in a small amount of water was added.
) was gradually added, and the polymerization reaction was continued for 1 hour.

The obtained crosslinked elastic body had an average particle diameter of 0,077 microns, a gel content of qo, o%, and a degree of swelling l'
ig, θ.

■ Production of graft copolymer g the interior of the polymerization can containing the crosslinked elastic body of soil.

After raising the temperature to ℃ and adding 0-0'i parts of sodium formaldehyde sulfoxylate, a mixture consisting of 70 parts of methyl methacrylate, 70 parts of butyl acrylate, o and ob parts of cumene hydroperoxide was heated for 1 hour. The polymerization reaction was continued for an additional 30 minutes after the addition was completed.

After this, a mixture of methyl methacrylate θ part, butyl acrylate 'o part, b cumene hydroperoxide o, and is part was continuously added to the same polymerization reactor over a period of 9 hours, and the polymerization reaction was carried out for 30 minutes after the addition was completed. This was continued to obtain a graft copolymer emulsion.

The obtained graft copolymer was salted out according to a conventional method, and the polymer was separated by t''J, washed with water, and dried to obtain a graft copolymer powder.

■ 0 parts of the graft copolymer obtained in the preparation of the resin solution was added to a mixed solution of 76 parts of methyl ethyl keto and 6 parts of toluene, stirred, and dissolved until the solid content was 20 parts (
A t% acrylic resin solution was prepared.

(3J Formation of ultraviolet absorber type coating) Add the type of ultraviolet absorber shown in Table 1 to the acrylic resin solution prepared according to the method described in (2) above at the proportion shown in the table (resin solid content). means the percentage of

) was added.

The solution after addition was applied to one side 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. The thickness of this film and the amount of ultraviolet absorber per unit area of the film are shown in Table 1.

(4) Properties of the film before being exposed outdoors The following properties of the polyethylene terephthalate film having a coating containing an ultraviolet absorber were measured before being exposed outdoors. The results are shown in Table 7.

(b) Light transmittance spectrophotometer at wavelength 3 θnm (
Measurement was performed using a new model 3λ3 manufactured by Hitachi.

(b) Growth rate Compliant with J Engineering S K-Aλ3 ke.

()j Puncture impact strength Tested using a puncture impact tester (manufactured by Toyo Seiki Co., Ltd.) on a sample of length iocm and width 10 cm, and the energy at the time of puncture is expressed in ky-1.

) Wavelength 3! ; Light transmittance at Onm ゛(
The same applies to case b).

(E) Visual determination of transparency The transparency of the film was determined by observing it with the naked eye. The criteria for judgment were as follows.

○: Transparency is poor, and no whitened areas are observed on the surface.

0 to △: Excellent transparency, with almost no whitened areas observed on the surface.

△...Transparency is slightly poor, and some whitened areas are observed on the surface.

Δ~×: Transparency is quite poor, and some whitened areas are observed on the surface RFU.

X: Transparency is extremely poor, with significant whitening on the surface.

(f) Adhesive strength of film: Judgment was made by attaching cellophane tape (made by Chiban) to a polyethylene terephthalate film and visually observing changes in the film after removing the cellophane tape. The criteria for judgment were as follows.

◎・・・Even if the cellophane tape is removed vigorously, no change is observed in the film.

○: When a piece of cellophane tape that has been stuck is removed vigorously, a very small amount of film is left behind, but when it is removed slowly, no change is observed in the film.

(G) The film on which the impact-resistant film has been formed is flapped in a strong wind of 0 m/sec for a certain period of time as shown in the perspective view in Figure 7, and then the film is blown away. The occurrence of cracks was visually determined.

In Fig. 7, group l is a blower, 1q2 is a wind tunnel, and l13 is
is a film with a length of 330 mm% and a width of 2107 nm.

(5) Properties of the film after outdoor exposure A polyethylene terephthalate film containing a UV absorber coating was exposed in a field in Yatabe-cho, Tsukuba-gun, Ibaraki Prefecture from January 1980 to January 1, 1975. The following properties were measured for the film after exposure. The results are shown in Table 1.

The elongation rate, puncture impact strength, light transmittance at a wavelength of SSO nm, and visual judgment of transparency are the same as in the method (4) for evaluating the properties of the film before outdoor exposure.

Comparative Example: Regarding a 4S polyethylene terephthalate film having the same properties as that used in Example 1, without forming a film, various properties were measured on the film before outdoor exposure in the same manner as in Example. Furthermore, the film was exposed outdoors in the same manner as in the same example, and various properties of the film after outdoor exposure were measured. The results are shown in Table 7.

Comparative Example U A film of acrylic resin solution C containing no ultraviolet absorber was formed on one side of a base polyethylene terephthalate film having the same properties as those used in Example 1.

Regarding this film, the various properties of the film were measured before being exposed to the outdoors in the same manner as in Example/1, and the film was further exposed to the outdoors in the same manner as in the case of the same example, and the various properties of the film after being exposed to the outdoors were measured. did. The results are shown in Table 1.

Comparative Example 3 100 parts by weight of raw material polyethylene terephthalate,! −
(2'-Hydroxy-left'-tert-butylphenyl)benzotriazole 0. ．． 3 f□,' parts by weight were blended. This mixture was made into a film shape by a known method and stretched 3.5 times in length and width.
The density is 839 J! i' /crrt, thickness is /2
A film of Sμ was obtained.

Regarding this film, as in Example 1, various properties were measured on the film before outdoor exposure, and then the film was exposed outdoors in the same manner as in the same example, and various properties were measured on the film after outdoor exposure. did. The results are shown in Table 1.

Comparative Example A polyethylene terephthalate film surface-treated with an ultraviolet absorber (LLumar) is sold by Martin Processing Company, Inc., USA.
, thickness/2stt), as in Example 1,
Various properties were measured on the film before outdoor exposure. Furthermore, the film was exposed outdoors in the same manner as in the same example, and various properties of the film after outdoor exposure were measured.

The results are shown in Table 1.

Comparative Example S One side of the base polyethylene terephthalate film having the same properties as used in Example 1 was coated with Japanese Patent Publication No. 30-37.
2-(2'-Hydroxy-y-tert-butylphenyl)benzotriazole was added to an acrylic resin synthesized according to the content described in Example 1 of Publication No. 33 at a ratio of /4'4 to the resin solid content. A UV absorber-containing film having the same thickness as in Example 1 was formed by coating by gravure coating and drying.

Regarding this film, in the same manner as in Example/
Various properties were measured. The results are shown in Table 7.

In addition, the film after the impact resistance test was exposed outdoors in the same manner as in Example/, and various properties of the exposed film were measured in accordance with Example/. did. The results are shown in Table 1.

Comparative Example 6 In Comparative Example S, the thickness of the film formed on the base film was set to 3. A film-forming film was obtained in the same manner as Comparative Example S except that S micron was used.

Regarding this film, in the same manner as in Example/
Various properties were measured. The results are shown in Table 1.

In addition, the film after the impact resistance test was exposed outdoors in the same manner as in Example 1, and various properties of the exposed film were measured in accordance with Example 1. did. The results are shown in Table 2.

/' [Note] *1 There are 9 types of ultraviolet absorbers as follows.

a...-1(2'-hydroxy-y-tertiary-
butylphenyl) benzotriazole b...λ, <1! -dihydroxybenzophenone C
...Euhydroxy-coumethoxybenzophenone d...22Hydihydroxy-gumethoxybenzophenone e...Co, 2'-dihydroxy-+, lI'-dimethoxybenzophenone f...Ethyl- From Tables 1 and 2, the following becomes clear.

(1) Even when the agricultural polyethylene terephthalate film according to the present invention is exposed outdoors, it is hardly affected by ultraviolet rays, and there is little decrease in elongation and impact strength. On the other hand, in the film formed by adding an ultraviolet absorber (Comparative Example 3) and in the case in which the ultraviolet absorber was tightly bonded to the film surface (Comparative Example q), the impact strength decreased significantly.

(2) Agricultural polyethylene terefter according to the present invention.
? -Also, even when exposed outdoors, there are no small cracks on the surface, no whitening of the surface, no yellowing of the entire surface, and almost no change in transparency. On the other hand, in the product that did not contain an ultraviolet absorber (comparative example), fine cracks appeared on the surface, the surface turned white, the entire surface turned yellow, and the transparency was significantly reduced. decreased. Comparative Example λ ~ Comparative Example Although the degree is not the same as that of Comparative Example, fine cracks and whitening occur on the surface, and the transparency is impaired. (3) Agriculture according to the present invention The film formed on one side of the polyethylene terephthalate has excellent impact resistance, so even if an impact stress is applied to the leather, it is difficult to crack and the film is difficult to peel off. On the other hand, when the film does not contain a crosslinked elastic body (Comparative Example S and Comparative Example 6), if no cranking occurs in the film,
Although it exhibits excellent weather resistance, the coating is prone to cracking due to impactive stress loads, and once cracks occur, the coating peels off, reducing mechanical properties and transparency.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of the agricultural polyethylene terephthalate film according to the present invention, and FIG. 2 is a cross-sectional view of the film according to the present invention when sunlight hits the film from the side where the acrylic resin film is provided. Figure 3 is a schematic diagram showing the transmission of ultraviolet rays when sunlight is applied to a conventional polyethylene terephthalate film in which UV absorbers are uniformly dispersed throughout the film. FIG. q is a perspective view showing a situation in which the impact resistance of a film formed on an agricultural polyethylene terephthalate film is tested. In the figure, /, 2/ are polyethylene terephthalate films, 2. ．． 22 is a film of acrylic resin containing an ultraviolet absorber, No. 3 is a polyethylene terephthalate film containing an ultraviolet absorber, and No. 3 is a wind tunnel film.
indicate the respective films. Applicant: Mitsubishi Monsanto Chemical Vinyl Co., Ltd. Representative: Patent Attorney: Yo Hase - (7 others) Figure 1 Figure 2 Figure 3 Figure 4 I 42 tFj

Claims (1)

[Claims] (1) In an agricultural polyethylene terephthalate film with a thickness of 0.0/-0,.3 mm stretched in the biaxial directions by a factor of C, O-S, and O, on one side,
An acrylic resin film containing an ultraviolet absorber and having a thickness of 7 to 70 microns is formed, and this acrylic resin is in the presence of crosslinked acrylic ester elastomer particles. Graft copolymer -71-, Stte, obtained by polymerizing a mixture of a methacrylic acid alkyl ester monomer or a methacrylic acid alkyl ester as a main component and a vinyl compound monomer copolymerizable with this, An agricultural polyethylene terephthalate film comprising S to M% by weight of the crosslinked acrylic ester elastomer.