JPH10329291A - Laminated weatherable polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent transparency and haze from deteriorating owing to the generation of whitening and a crack by providing a laminated coating obtained by copolymerizing a benzotriazole reactive ultraviolet absorber with a plurality of acrylic monomers, at least, on one of the faces of polyester film. SOLUTION: A layer made up of a resin layer obtained by copolymerizing a benzotriazole reactive ultraviolet absorber with at least, two or more different types of acrylic monomer, is formed, at least, on one of the faces of the polyester film. The benzotriazole reactive ultraviolet absorber to be used is 2-2'- hydroxy 5' methacryloxyethylphenyl 2H benzotriazole. Especially methyl methacrylate is used as one of the two or more different types of acrylic monomer and the monomers other than the methyl methacrylate are preferably acrylic acid, butyl acrylate, 2-hydroxyethyl methacrylate and glycidyl methacrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laminated weather-resistant polyester film, and more particularly to a laminated weather-resistant polyester film having excellent transparency, durability, adhesion, and ultraviolet absorption.

[0002]

2. Description of the Related Art Heretofore, (1)
An ultraviolet absorbent kneaded into the entire polyester film (Japanese Patent Publication No. 57-6470); (2) An acrylic resin or the like which is mixed with an ultraviolet absorbent and laminated on a polyester film (Japanese Utility Model Application Laid-Open No. 56-159239). Gazette,
(Japanese Patent Publication No. 4-2101), (3) Lamination of a copolymerized acrylic resin of a benzotriazole-based reactive ultraviolet absorber and methyl methacrylate (Japanese Unexamined Patent Publication No. 9-48095)
Is known.

However, when a polyester film is kneaded with an ultraviolet absorber over the entire surface, the film surface is deteriorated when exposed to ultraviolet light for a long time, and the transparency and haze are reduced due to the occurrence of cracks and the like. An acrylic resin to which an ultraviolet absorber was added and mixed and laminated on a polyester film had poor weather resistance due to poor compatibility and insufficient adhesion to the polyester film. In addition, a laminated acrylic resin of a benzotriazole-based reactive UV absorber and methyl methacrylate has the disadvantage that when exposed to high humidity for a long time, the coating film whitens and the transparency of the film is greatly reduced. Had.

[0004]

DISCLOSURE OF THE INVENTION The present invention is intended to prevent a decrease in transparency and haze due to the occurrence of whitening or cracks,
Further, the present invention provides a film having excellent long-term weather resistance.

[0005]

That is, the present invention provides a polyester film having a laminated film formed by copolymerizing at least one surface of a polyester film with a benzotriazole-based reactive ultraviolet absorbent and at least two or more acrylic monomers. The present invention relates to a laminated weather-resistant polyester film.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The polyester film referred to in the present invention is:
Polyethylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, and a copolymer film thereof, which are obtained by melt-extruding a polyester polymer, stretching the polymer in the longitudinal direction and / or the width direction as necessary, and heat-setting. Particularly preferred is a biaxially oriented polyester film.

[0008] The thickness of the polyester film of the present invention is:
Although not particularly limited, a range of 12 to 250 μm is desirable. Especially when used as an agricultural house, 50 to 2
The range is preferably 50 μm, and in terms of practical mechanical properties and flexibility, the range is preferably 100 to 200 μm.

In the present invention, a layer composed of a resin layer obtained by copolymerizing a benzotriazole-based reactive ultraviolet absorber and at least two or more acrylic monomers is formed on at least one surface of the polyester film.

Benzotriazole reactive ultraviolet absorbers include 2-2'-hydroxy 5 'methacryloxyethyl phenyl 2H benzotriazole, 2-2 hydroxy 3 tertbutyl 5' methyl phenyl 5 chloro benzo triazole and 2-2 'hydroxy. 5 'methylphenylbenzotriazole, 2-2' hydroxy 5 'ter
t-butylphenylbenzotriazole, 2-2'hydroxy3'5'ditertbutylphenylbenzotriazole, 2-2'hydroxy3'5'ditertamylphenylbenzotriazole, 2-2'hydroxy3 '
5 'ditertbutylphenyl 5-chlorobenzotriazole, 2-2 methylenebis4-1,1,3,3 tetramethylbutyl 6-2Hbenzotriazol-2-ylphenol and the like are used.

The following can be used as the acrylic monomer to be copolymerized. For example, alkyl acrylate, alkyl methacrylate (the alkyl group is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group,
Hydroxy such as ethylhexyl, lauryl, stearyl, cyclohexyl, phenyl, benzyl, and phenylethyl), 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate. Group-containing monomer, acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N
-Methylol methacrylamide, N, N-dimethylacrylamide, N-methoxymethylacrylamide, N-
Amide group-containing monomers such as methoxymethyl methacrylamide and N-phenylacrylamide; amino group-containing monomers such as N, N-diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate; epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate; Is used.

In the present invention, the laminated weather-resistant polyester film provided with the laminated film having the above structure has a haze value of 10% after 10 cycles in an ultraviolet irradiation wet heat cycle test.
Or less, preferably 6% or less, more preferably 5% or less. If the haze value exceeds 10%, even if the weather resistance such as the film elongation is improved, the light transmittance is poor. When it is used for a cover film made of a material, troubles such as poor appearance are caused.

In the present invention, in order to reduce the haze, two or more acrylic monomers are used to form a copolymer with a benzotriazole-based reactive ultraviolet absorber. The two or more kinds of acrylic monomers are selected from the above-mentioned ones, and it is preferable to use methacrylic acid ester as one component, and it is particularly preferable to use methyl methacrylate in terms of weather resistance and transparency. Preferred as the monomer species other than methyl methacrylate are acrylic acid, acrylate (an alkyl group having 1 to 18 carbon atoms as an ester chain), methacrylate other than methyl methacrylate, an amide group, a methylol group, a glycidyl group, An acrylic monomer having a siloxyl group is an example. Particularly preferred are acrylic acid, butyl acrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate. The copolymerization of these improves the adhesion between the laminated film and the base polyester film, and the effect of preventing the laminated film from whitening. I do.

When only one acrylic monomer is copolymerized, the adhesion to the substrate, the weather resistance of the laminated film, and the effect of preventing whitening become insufficient.

In the copolymerization of the benzotriazole-based reactive ultraviolet absorber and two or more acrylic monomers, the copolymerization ratio of the benzotriazole-based reactive ultraviolet absorber is 10 to 80% by weight, preferably 30 to 70% by weight. And more preferably 45 to 60% by weight. The acrylic monomer to be copolymerized is composed of, for example, a methacrylic acid ester and another acrylic monomer, and the copolymerization ratio of the other acrylic monomer is 0.1 to 50% by weight, preferably 0.5 to 30% by weight. % By weight, more preferably 1 to 20
Desirably, it is% by weight.

The glass transition point of the copolymer varies depending on the type and ratio of the monomers to be copolymerized. The glass transition point of the copolymer is preferably 40 ° C. or more, and more preferably 50 to 70 ° C. or more. It is preferable in terms of blocking resistance of the film.

Various additives and various kinds of polymers may be mixed with the copolymer as long as the effects of the present invention are not impaired. For example, antioxidants, antistatic agents, photodeterioration inhibitors, organic lubricants, organic and inorganic fine particles, and the like can be used.

In particular, the combined use of a crosslinking agent in the laminated film of the present invention further improves the whitening prevention effect of the coating film. As the crosslinking agent, epoxy-based, melamine-based, isocyanate-based, oxalin-based and the like can be used, in particular,
It is effective to use a melamine-based crosslinking agent.

The thickness of the laminated film is preferably a thickness at which the effect of the present invention is exhibited, specifically, about 1 to 10 μm.

[0020]

[Measurement and evaluation of characteristics] The following methods were used to measure the characteristics in Table 1.

(A) UV irradiation wet heat cycle test UV light accelerated tester “I-Super” UV tester (type SUV-W131 manufactured by Iwasaki Electric Co., Ltd.) was used and light (ultraviolet intensity 100 mw / cm ² , atmosphere condition 60). 50% RH x 8 hours) → Dew (Condensation condition 35)
℃ 100% RH × 8 hours) → rest (resting condition 35 ° C.7)
A cycle weather resistance test (0% RH × 8 hours) is performed for 10 cycles, and changes in the film are evaluated.

(B) Total light transmittance and haze The total light transmittance and haze before and after the UV irradiation wet heat cycle test were measured using a direct reading haze computer HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.).

(C) Whitening of the coating film The whitening of the film before and after 10 cycles of the UV irradiation wet heat cycle test was visually judged.

：: no change Δ: slightly whitened ×: whitened

(D) Change in color of the coating film The change in the color of the film before and after 10 cycles of the UV irradiation wet heat cycle test was judged with the naked eye.

：: No change Δ: Slightly changed to yellow ×: Changed to yellow-brown

(E) Adhesiveness of the laminated coating film The laminated coating film was scratched in a grid with a cutter, and the peeling state of the coating film when vigorously peeled off with a cellophane tape manufactured by Nichiban Co., Ltd. was evaluated. Was regarded as good.

：: No peeling at all △: Slight peeling ×: Peeling over the entire surface of the film

[0029]

EXAMPLES Examples will be described, but the present invention is not necessarily limited to these examples.

Example 1 Benzotriazole type ultraviolet absorbing monomer (2-2'-
50% by weight of hydroxy 5 'methacryloxyethylphenyl 2H benzotriazole) and methyl methacrylate 4
A resin obtained by copolymerizing 3% by weight and 7% by weight of butyl acrylate (molecular weight: 78,000, glass transition temperature: 63 ° C.) was dissolved in a mixed solvent of toluene / methyl ethyl ketone (2: 1) to obtain a solution having a solid content of 20% by weight. . This solution was applied to one surface of a polyethylene terephthalate film ("Lumirror" type T60, 100 μm thick, manufactured by Toray Industries, Inc.) using a metaling bar so as to have a solid content of 4 μm, and dried at 120 ° C. for 1 minute. .

The film was subjected to an ultraviolet irradiation wet heat cycle test. In the 10 cycle test, no change was observed in the laminated coating film, and the haze was 5%.

Example 2 Benzotriazole UV absorbing monomer (2-2'-
50% by weight of hydroxy 5 'methacryloxyethylphenyl 2H benzotriazole) and methyl methacrylate 3
2% by weight, butyl acrylate 17% by weight, acrylic acid 1
% By weight of a resin (molecular weight: 82000, glass transition temperature: 58 ° C.) was mixed with toluene / methyl ethyl ketone (2:
It was dissolved in the mixed solvent of 1) to obtain a solution having a solid content of 20% by weight. This solution was applied to a polyethylene terephthalate film (“Lumirror” type T60 100 μm, manufactured by Toray Industries, Inc.).
(Thickness) using a metaling bar to apply a solid content of 4 μm in the same manner as in Example 1 using a metaling bar.
Dried at ℃ for 1 minute.

The film was subjected to an ultraviolet irradiation wet heat cycle test. In the 10 cycle test, no change was observed in the laminated coating film, and the haze was 3.5%.

Example 3 Benzotriazole type ultraviolet absorbing monomer (2-2'-
50% by weight of hydroxy 5 'methacryloxyethylphenyl 2H benzotriazole) and methyl methacrylate 3
2% by weight, 17% by weight of butyl acrylate and 1% by weight of 2hydroxyethyl methacrylate (molecular weight: 82,000, glass transition temperature: 51 ° C.)
It was dissolved in a mixed solvent of methyl ethyl ketone (2: 1) to obtain a solution having a solid content of 20%. This solution was applied to one side of a polyethylene terephthalate film (“Lumirror” type T60, 100 μm thick, manufactured by Toray Industries, Inc.) using a metalling bar to a thickness of 4 μm in the same manner as in Example 1 using a metalling bar. Dried at ℃ for 1 minute.

The film was subjected to an ultraviolet irradiation wet heat cycle test. In the 10 cycle test, no change was observed in the laminated coating film, and the haze was 4%.

Example 4 Benzotriazole type ultraviolet absorbing monomer (2-2'-
70% by weight of hydroxy 5 'methacryloxyethylphenyl 2H benzotriazole) and methyl methacrylate 1
A resin (molecular weight: 114,000, glass transition temperature: 69 ° C.) obtained by copolymerizing 5% by weight, 14% by weight of butyl acrylate, and 1% by weight of acrylic acid was dissolved in a mixed solvent of toluene / methyl ethyl ketone (2: 1), and the solid content was adjusted. A 20% by weight solution was obtained. This solution was treated with a polyethylene terephthalate film ("Lumirror" type T60100 manufactured by Toray Industries, Inc.).
(thickness: μm) was applied using a metaling bar to a thickness of 4 μm with a solid content film thickness, and dried at 120 ° C. for 1 minute.

The film was subjected to an ultraviolet irradiation wet heat cycle test. In the 10 cycle test, no change was observed in the laminated coating film, and the haze was 3.5%.

Example 5 Benzotriazole UV absorbing monomer (2-2'-
50% by weight of hydroxy 5 'methacryloxyethylphenyl 2H benzotriazole) and methyl methacrylate 3
2% by weight, butyl acrylate 17% by weight, acrylic acid 1
% By weight of a resin (molecular weight: 82000, glass transition temperature: 58 ° C.) was mixed with toluene / methyl ethyl ketone (2:
It was dissolved in the mixed solvent of 1) to obtain a solution having a solid content of 20%.
To this solution, 2 parts of methylolated melamine (“Cymel” 370 manufactured by Mitsui Cytec Co., Ltd.) was added in a solid content ratio of 2 parts. This solution was applied to a polyethylene terephthalate film (“Lumirror” type T60 100 μm, manufactured by Toray Industries, Inc.).
Thickness) using a metaling bar on one side
m and dried at 120 ° C. for 1 minute.

The film was subjected to an ultraviolet irradiation wet heat cycle test. In the 10 cycle test, no change was observed in the laminated coating film, and the haze was 2.5%.

Example 6 Benzotriazole type ultraviolet absorbing monomer (2-2'-
50% by weight of hydroxy 5 'methacryloxyethylphenyl 2H benzotriazole) and methyl methacrylate 3
A resin (molecular weight: 82,000, glass transition temperature: 51 ° C.) obtained by copolymerizing 2% by weight, 17% by weight of butyl acrylate, and 1% by weight of 2hydroxyethyl methacrylate is dissolved in a mixed solvent of toluene / methyl ethyl ketone (2: 1). And a solution having a solid content of 20% by weight. Methylolated melamine (“Cymel” 3 manufactured by Mitsui Cytec Co., Ltd.) is added to this solution.
70) at a solid content ratio of 2 parts. This solution was applied to a polyethylene terephthalate film (manufactured by Toray Industries, Inc., “Lumirror” type T60, 100 μm thick) using a metalling bar so as to have a solid content of 4 μm.
Dry at 120 ° C. for 1 minute.

The film was subjected to an ultraviolet irradiation wet heat cycle test. In the 10 cycle test, no change was observed in the laminated coating film, and the haze was 2.5%.

Comparative Example 1 Resin (2-2'-hydroxy 5 'methacryloxyethyl phenyl 2H benzotriazole 5) obtained by copolymerizing a benzotriazole-based reactive ultraviolet absorber and acrylic
A resin obtained by copolymerizing 0% by weight and 50% by weight of methyl methacrylate: molecular weight 63000, glass transition temperature 90 ° C.) was dissolved in a mixed solvent of toluene / methyl ethyl ketone (2: 1) to obtain a solution having a solid content of 20% by weight. . This solution was applied to one surface of a polyethylene terephthalate film ("Lumirror" type T60, 100 μm thick, manufactured by Toray Industries, Inc.) using a metaling bar so as to have a solid content of 4 μm, and dried at 120 ° C. for 1 minute. .

The film was subjected to an ultraviolet irradiation wet heat cycle test, and the laminated coating film was whitened in 10 cycles. At this time, the haze of the laminated film was 15%.

Table 1 shows the evaluation results of the UV irradiation wet heat cycle tests of Examples 1 to 6 and Comparative Example 1.

[0045]

[Table 1]

[0046]

The laminated weather-resistant polyester film of the present invention has an effect that it can be stably used for outdoor applications for a long period of time as compared with a general synthetic resin film due to its excellent weather resistance. Utilizing its excellent weather resistance, it can be widely used as a building film for agricultural houses, solariums, roofs of rainball practice areas, display labels for use outdoors, electric signs, and cover films for various base materials. it can.

Claims (4)

[Claims] 1. A laminated weatherable polyester comprising a laminated film formed by copolymerizing a benzotriazole-based reactive ultraviolet absorber and at least two kinds of acrylic monomers on at least one surface of a polyester film. the film. 2. The laminated weather-resistant polyester film according to claim 1, wherein a haze after 10 cycles of a UV-wet heat-and-heat cycle test of the laminated weather-resistant polyester film is 10% or less. 3. The method according to claim 1, wherein the acrylic monomer comprises at least one selected from acrylic acid, butyl acrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate, and methyl methacrylate. Or the laminated weather-resistant polyester film according to claim 2. 4. The laminated weatherable polyester film according to claim 1, wherein the copolymerization amount of the benzotriazole-based reactive ultraviolet absorber is 10 to 80% by weight.