JPH08104776A - Thermoplastic resin film and sheet - Google Patents

Abstract

PURPOSE: To provide a thermoplastic resin film which has a UV screening function and hardly suffers bleeding of the UV absorber contained therein and obtain the thermoplastic resin sheet excellent in weathering resistance by laminating the films. CONSTITUTION: This film is made from a thermoplastic resin containing a UV absorber comprising a benzotriazole dimer represented by the formula. In the formula, R is alkyl, nitro or alkoxyl; Z is alkyl or halogen; and t is an integer of 1 to 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin film having a function of blocking ultraviolet rays and a thermoplastic resin sheet obtained by laminating and integrating this thermoplastic resin film on a thermoplastic resin sheet substrate.

[0002]

2. Description of the Related Art Generally, as a means for suppressing the photo-deterioration of various thermoplastic resin sheets to improve their weather resistance, an ultraviolet blocking film having an ultraviolet absorber contained in a thermoplastic resin on the surface of the resin sheet. The method of stacking is widely used.

Conventionally, benzotriazole-based ones have been mainly used as the ultraviolet absorber used in the above-mentioned ultraviolet-blocking film, and among them, for example, 2
-(2'-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 '.
5'-di-tert-butylphenyl) Benzotriazole-based compounds, such as benzotriazole, which have only one functional group related to UV absorption, have alkyl groups, halogens, etc. added to increase the molecular weight. .

On the other hand, as a means for laminating the ultraviolet blocking film and the thermoplastic resin sheet base material, a thermoplastic resin sheet base material is extruded and immediately after that, a laminate roll is used to block the ultraviolet light shielding from the sheet base material. A method of heat-sealing the film with a conductive film is generally adopted. Further, the laminated sheet thus obtained is often processed into a secondary product by thermoforming such as vacuum forming or pressure forming.

[0005]

However, in the above conventional laminated sheet, when laminating with a laminating roll,
Alternatively, during thermoforming of a secondary product, the UV absorber contained in the UV blocking film bleeds out and adheres to the laminating roll and adversely affects the sheet appearance, or deteriorates the appearance of the thermoformed secondary product. Also, the bleed-out reduces the content of the ultraviolet absorber in the ultraviolet-shielding film, and since the bleed-out ultraviolet absorber is easily lost by wind and rain, the ultraviolet-shielding function becomes insufficient, and the weather resistance of the sheet is improved. There was a problem of decreasing the sex.

The above bleed-out has good compatibility between the ultraviolet absorber and the thermoplastic resin, but the bleed-out is due to the fact that the ultraviolet absorber has a small molecular weight or the molecular shape is monotonous even though the ultraviolet absorber has a large molecular weight. It is considered that since the molecules of the ultraviolet absorber move easily in the plastic resin, the movement of the molecules of the ultraviolet absorber becomes intense and exudes to the film surface especially when heated.

In view of the above-mentioned circumstances, the present invention provides a thermoplastic resin film having a function of blocking ultraviolet rays, which hardly causes bleed-out of the ultraviolet absorbent contained therein, and at the same time, the thermoplastic resin film It is intended to realize a thermoplastic resin sheet having excellent weather resistance by laminating.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above object, and as a result, when a specific benzotriazole dimer was used as an ultraviolet absorber, it was allowed to contain it. Further, they have found that the thermoplastic resin film does not cause bleed-out of the ultraviolet absorber even when placed under heating and exhibits a high ultraviolet shielding function, and thus completed the present invention.

That is, in the thermoplastic resin film according to claim 1 of the present invention, the thermoplastic resin contains an ultraviolet absorber composed of a benzotriazole dimer represented by the following general formula (I). The configuration is adopted.

[0010]

Embedded image Further, a thermoplastic resin sheet according to claim 2 of the present invention adopts a constitution in which the thermoplastic resin film of claim 1 is laminated and integrated on at least one surface of a thermoplastic resin sheet base material. .

[0011]

Detailed Structure and Function of the Invention The benzotriazole dimer represented by the general formula (I) used as an ultraviolet absorber in the present invention is 2- (2'-hydroxyphenyl) having good compatibility with a thermoplastic resin. ) It is a form in which two benzotriazoles are bonded, and also has good compatibility and also has a large molecular weight, so when blended with a thermoplastic resin, it will not easily escape from the resin matrix, and thus bleed even under heating. Out is less likely to occur. Further, since the ultraviolet absorption amount per unit molecular weight of this benzotriazole dimer is larger than that of other general ultraviolet absorbers, there is an advantage that a good ultraviolet shielding effect can be obtained with a small amount of compounding.

A specific example of such a benzotriazole dimer is 2.2'-methylenebis (4-methyl-).
6-benzotriazol-2-ylphenol), 2.
2'-methylenebis [4- (1.1.3.3-tetramethylbutyl) -6- (2H-benzotriazole-2-
Il) phenol] and the like.

The blending amount of the above-mentioned benzotriazole dimer in the thermoplastic resin film depends on the kind of thermoplastic resin used in this film and the degree of weather resistance required for the thermoplastic resin sheet on which the resin film is to be laminated. Although it is determined, the range of 1 to 25 parts by weight is generally preferable with respect to 100 parts by weight of the thermoplastic resin of the resin film. If the amount is less than 1 part by weight, the effect of blocking ultraviolet rays will be insufficient. On the other hand, when it exceeds 25 parts by weight, the melt viscosity of the resin composition is extremely lowered, and extrusion molding is difficult due to drawdown, and the ultraviolet absorber appears on the resin surface, resulting in poor adhesion on the roll. Film cannot be formed.

The thermoplastic resin used in the thermoplastic resin film of the present invention includes polymethylmethacrylate resin, polymethylmethacrylate resin containing a rubber component, vinylidene fluoride-polymethylmethacrylate copolymer resin, polycarbonate resin. Etc. can be mentioned.

The thickness of the thermoplastic resin film is 50
The thickness is preferably at least μm, and if it is too thin, there is a risk of causing problems such as breakage when laminating by applying tension to the thermoplastic resin sheet base material.

On the other hand, the thermoplastic resin sheet of the present invention is
A thermoplastic resin film containing the above-mentioned ultraviolet absorber is integrally laminated on a thermoplastic resin sheet base material. This thermoplastic resin film has a two-layer structure in which it is laminated on one side of the sheet base material, It includes any of the three-layer structure laminated on both sides. The laminating means is not particularly limited, but usually a method of heat-sealing the sheet base material and the ultraviolet blocking film by using a laminating roll immediately after extrusion molding the thermoplastic resin sheet base material is adopted. do it.

However, in such a laminated sheet, since the thermoplastic resin film containing the ultraviolet absorber does not cause the bleed-out of the ultraviolet absorber even under heating, it is possible to perform the heat fusion by the above-mentioned lamination. There is no fear of deterioration of appearance due to the bleed-out, and there is no deterioration of appearance due to the bleed-out when the laminated sheet is processed into a secondary product by thermoforming such as vacuum forming or pressure forming, and the thermoplastic property is high. Exhibits excellent weather resistance based on the UV blocking function of the resin film.

Examples of the resin component of the thermoplastic resin sheet base material include polycarbonate resin, vinyl chloride resin, acrylic resin, polystyrene resin and the like.

[0019]

【Example】

Example 1 Polycarbonate resin (trade name: Iupilon E2000
F ... Mitsubishi Gas Chemical Co., Ltd.) 100 parts by weight, 2.2'-methylenebis [4- (1.1.3.3
-Tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] (trade name: LA-31 ...
15 parts by weight of Asahi Denka Kogyo Co., Ltd. was added and extrusion molded with a φ40 mm extruder to produce a polycarbonate film having a thickness of 50 μm. On the other hand, a polycarbonate resin (trade name: Tafflon V-2700 ... manufactured by Idemitsu Petrochemical Co., Ltd.) is used for φ4.
A 3 mm thick sheet was extruded with a 0 mm vent type extruder, and at the same time, the above polycarbonate film was laminated on the surface of this sheet to prepare a laminated sheet.

Example 2 To 100 parts by weight of a polymethylmethacrylate resin (trade name: MHG ... manufactured by Sumitomo Chemical Co., Ltd.), 3.5 parts by weight of the same ultraviolet absorber as that used in Example 1 was added to give a diameter of 40 mm.
It was extruded by an extruder to produce a polymethylmethacrylate film having a thickness of 50 μm. On the other hand, 100 parts by weight of a polycarbonate resin (trade name: Tafflon V-2700 ... manufactured by Idemitsu Petrochemical Co., Ltd.) contains titanium oxide (trade name: R650 ...
Sakai Chemical Industry Co., Ltd.) 0.09 parts by weight, crosslinked acrylic beads (trade name: MBX-8 ... Sekisui Chemical Co., Ltd.) 0.7
Add 5 parts by weight, and use a 40 mm diameter vent type extruder for 3 m.
At the same time as extruding the m-thick milky white sheet, the above polymethylmethacrylate film was laminated on the surface of the milky white sheet to prepare a laminated sheet.

Comparative Example Polymethylmethacrylate resin (same as Example 2) 10
To 0 part by weight, 3.5 parts by weight of 2- (5-methyl-2-hydroxyphenyl) benzotriazole was added, and φ40
It was extruded by a mm extruder to prepare a polymethylmethacrylate film having a thickness of 50 μm. Then, this film was laminated on the surface of the polycarbonate resin sheet in the same manner as in Example 1 to produce a laminated sheet.

The laminated sheets of the above Examples and Comparative Examples were subjected to bleeding and weather resistance evaluation tests by the following methods. Table 1 shows the results.

[Bleed Evaluation A] With respect to the laminated sheet obtained by laminating immediately after extrusion with a vent type extruder, a reflection image of a fluorescent lamp was visually observed on the extrusion line at an angle of about 60 degrees to obtain a bleed product. Check for
The sample without bleed was evaluated as ◯, and the sample with bleed was evaluated as x.

[Bleed Evaluation B] The test piece of the laminated sheet was exposed to an environment of 120 ° C. for 12 hours, and then the presence or absence of bleeding was examined, and the one without bleeding was evaluated as ◯, and the one with bleeding was evaluated as x. .

[Evaluation of Weather Resistance] A test piece of the laminated sheet was put on a super energy tester (manufactured by Suga Test Instruments Co., Ltd.), and the temperature was 63 ° C. for 5 minutes.
After irradiation for 240 hours under the condition of 3% RH,
The color difference (ΔY) from the original test piece before irradiation was examined with a color difference meter (manufactured by Nippon Denki Kogyo Co., Ltd.).

[0026]

[Table 1] From the results in the above table, the thermoplastic resin film according to the present invention does not cause bleed-out of the contained ultraviolet absorber even under heating, and has a high ultraviolet shielding function, and is excellent in a thermoplastic resin sheet laminated with this. It can be seen that weather resistance can be imparted.

[0027]

According to the invention of claim 1, there is provided a thermoplastic resin film containing an ultraviolet absorber, which does not cause bleed-out of the ultraviolet absorber even under heating and has a high ultraviolet shielding function. It

According to the invention of claim 2, since the thermoplastic resin film of claim 1 is laminated on a sheet base material as a thermoplastic resin sheet, the lamination means is a laminate immediately after extrusion molding of the sheet base material. Even if heat fusion is adopted, there is no bleed-out of the UV absorber, and there is no bleed-out when processing a laminated sheet into a secondary product by thermoforming such as vacuum forming or pressure forming, so it has an appearance. And a good thermoplastic resin film capable of exhibiting excellent weather resistance based on the laminated thermoplastic resin film.

Claims (2)

[Claims] 1. A thermoplastic resin film comprising a thermoplastic resin containing an ultraviolet absorber comprising a benzotriazole dimer represented by the following general formula (I). Embedded image 2. A thermoplastic resin sheet obtained by laminating and integrating the thermoplastic resin film according to claim 1 on at least one surface of a thermoplastic resin sheet substrate.