JPH09176476A - UV resistant polycarbonate resin composition - Google Patents

Abstract

(57) Abstract: The present invention has characteristics of a polycarbonate resin such as transparency, impact resistance and flame retardancy, and is excellent in ultraviolet light resistance that does not lose transparency even when recycled. A polycarbonate resin composition suitable for sheets and films. A polycarbonate resin composition containing a triaryltriazine compound represented by the following general formula (1) in an amount of 0.1 to 10% by weight based on the polycarbonate resin. [Effect] The polycarbonate resin composition of the present invention is suitable for producing a sheet and a film which have little yellowing due to UV resistance and are excellent in transparency. Embedded image (In the formula, R represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a halogen atom or an alkyl group having 2 to 6 carbon atoms substituted with an alkoxy group having 1 to 15 carbon atoms, or a benzyl group; 'Represents a methyl group.)

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has excellent ultraviolet resistance that does not impair the original characteristics of the polycarbonate resin such as transparency, impact resistance and flame retardancy, and does not lose transparency even when recycled. The present invention relates to a polycarbonate resin sheet and film.

[0002]

2. Description of the Related Art Polycarbonate sheets are excellent in transparency, impact resistance, heat resistance, flame retardancy, etc., so that they can be used for building materials such as greenhouse covering materials, arcades, roofing materials for daylighting, wainscots for sidewalks, high speed Widely used for road materials such as road fences and industrial materials such as nameplates. When a polycarbonate sheet is used outdoors, it is used with an ultraviolet absorber added, but even after a few years, ultraviolet rays cause yellowing and fine cracks on the polycarbonate resin surface, causing devitrification, Furthermore, strength is reduced. As a countermeasure against this, a sheet whose surface is subjected to ultraviolet ray resistance has been developed.

As a method of subjecting the sheet surface to ultraviolet ray resistance, there are a method of laminating an acrylic resin and a method of laminating with a polycarbonate resin itself. These methods are
A large amount of an ultraviolet absorber is added to the acrylic resin or polycarbonate resin layer provided on the surface of the sheet to prevent deterioration of the polycarbonate sheet substrate due to ultraviolet rays.

As a method for laminating the acrylic resin, there are a method of thermally laminating the acrylic film at the time of manufacturing the sheet, a method of applying an acrylic paint after the sheet is manufactured, a method of coextrusion molding the acrylic resin and the polycarbonate resin, and the like. Yes (Japanese Patent Publication No. 47-19119,
JP-A-55-59929). However, since these methods use different resins, the impact strength of the polycarbonate sheet itself or the heat resistance of the sheet surface is reduced, and further, when it is recycled, it becomes cloudy during melt mixing. There is a problem that it cannot be reused as a transparent resin. On the other hand, co-extrusion molding is generally used for laminating polycarbonate resins (Japanese Patent Publication No. 3-54626 and Japanese Patent Publication No. 6-41162).

The UV absorber added to the UV resistant layer is usually 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole, 2- (2'-hydroxy-5'-t-). Octylphenyl) -benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2,2-methylenebis [4- (1,1,3,3) 3,-
A benzotriazole-based compound such as tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] is used. However, these UV absorbers cause the most deterioration of polycarbonate resins.
There is a problem that absorption of ultraviolet rays in the vicinity of nm is insufficient, compatibility with the polycarbonate resin is poor, and volatilization is likely to occur. Therefore, it has been necessary to add a large amount, which leads to an increase in cost, pollutes the working environment, and causes a poor appearance of the sheet. In addition, a high molecular weight type UV absorber has been developed, but since there are few units capable of absorbing UV light in one molecule, it is necessary to add several tens% by weight to obtain sufficient UV resistance. However, this may lead to a considerable increase in cost, may cause deterioration of the physical properties of the polycarbonate resin itself, and may impair the transparency of the polycarbonate resin.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is to solve the above-mentioned problems in the prior art, to retain the original characteristics of polycarbonate resin such as transparency, impact resistance and flame retardancy, and to recycle it. Another object of the present invention is to provide a polycarbonate resin sheet and film excellent in ultraviolet resistance that does not lose transparency even when used.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the following general formula (1)

Embedded image

(In the formula, R is a hydrogen atom, and has 1 to 1 carbon atoms.
8 alkyl groups, halogen atoms or 1 to 15 carbon atoms
Represents an alkyl group having 2 to 6 carbon atoms substituted with an alkoxy group or a benzyl group, and R ′ represents a methyl group. )
When a triaryltriazine compound represented by is used, sufficient UV resistance can be obtained with an addition amount of half or less of the benzotriazole-based UV absorber, and the compatibility with the polycarbonate resin is good, so that the volatility is high. Therefore, the present invention was reached, and the present invention was reached.

That is, according to the present invention, a polycarbonate resin sheet and a film are provided with a UV resistant layer on one or both sides, and the UV resistant layer has the following general formula (1):

Embedded image

(In the formula, R is a hydrogen atom and the number of carbon atoms is 1 to 1)
8 alkyl groups, halogen atoms or 1 to 15 carbon atoms
Represents an alkyl group having 2 to 6 carbon atoms substituted with an alkoxy group or a benzyl group, and R ′ represents a methyl group. )
And a polycarbonate resin containing a triaryltriazine compound in an amount of 1 to 10% by weight with respect to the polycarbonate resin, having a film thickness of 10 to 100 μm.

The triaryltriazine compound represented by the general formula (1) is a benzotriazole-based ultraviolet absorber which has been used in polycarbonate resins up to now for ultraviolet rays in the vicinity of 280 to 300 nm which cause the most photodegradation of polycarbonate resins. It can absorb more than twice as much and is less volatile because it has good compatibility with polycarbonate resin. Therefore, excellent UV resistance can be obtained with an addition amount of half or less of the benzotriazole-based UV absorber.

In the present invention, the polycarbonate resin used in the ultraviolet resistant layer or the substrate layer is 2,2-bis (4-hydroxyphenyl) alkane or 2,2-bis (4-hydroxy-3,5-dihalogenophenyl). ) A polymer produced by a known method from a bisphenol compound represented by an alkane. Although the molecular weight is not particularly limited,
From the viewpoint of extrusion moldability and mechanical strength, those having a viscosity average molecular weight of 20,000 to 30,000 are preferable. Then, a part of the polymer may include a structural unit derived from a fatty acid diol in the polymer skeleton or a structural unit having an ester bond.

Further, in the above polycarbonate resin,
Organic UV absorbers such as benzotriazole-based, benzophenone-based, benzoate-based, and salicylate-based currently commercially available or inorganic UV absorbers such as titanium oxide, zinc oxide, and cerium oxide may be added. It may contain a light stabilizer, an antioxidant, a heat stabilizer, an antistatic agent, a heat ray shielding agent, a flame retardant, a lubricant, a pigment, a filler and the like.

The content of the ultraviolet absorbent in the ultraviolet resistant layer depends on the ultraviolet absorbing ability of the ultraviolet absorbent used and the thickness of the ultraviolet resistant layer, but is 0.
A range of 1 to 10% by weight is preferred. More preferably 1 to
It is in the range of 8% by weight, particularly preferably in the range of 2 to 5% by weight. If the content is less than 1% by weight, the ultraviolet resistance is insufficient, and if it exceeds 10% by weight, not only a remarkable difference in the effect of improving the ultraviolet resistance is not observed, but also in the ultraviolet resistant layer. Coloring peculiar to the ultraviolet absorber occurs, and further, when the sheet is formed, the cooling roll is volatilized and the work environment is soiled due to volatilization of the ultraviolet absorber, which is a cause of impairing the sheet appearance.
The thickness of the UV resistant layer may be any thickness as long as it has the required UV resistance, but in practice it is preferably in the range of 10 to 100 μm, and more preferably in the range of 30 to 80 μm. 10 μm
If the thickness is 100 μm or more, a sufficient ultraviolet absorption effect cannot be obtained. On the other hand, if the thickness is 100 μm or more, the ultraviolet resistance is not significantly improved.

The method for producing the multilayer sheet and film comprising the substrate layer and the UV resistant layer according to the present invention is not particularly limited. For example, a co-extrusion method in which raw material resins for the substrate layer and the UV resistant layer are simultaneously melt-extruded and molded, a method in which the UV resistant layer is simultaneously melt-extruded and laminated when the substrate layer is extruded into a sheet shape, and previously formed into a film shape. A method of continuously thermally laminating the formed UV resistant layer during extrusion molding of the substrate layer, a method of thermocompression bonding the sheet-shaped or film-shaped substrate layer and the UV resistant layer with a press machine, and the like are used.

[0016]

Next, the present invention will be described more specifically with reference to examples. The evaluation and test methods used in this example are shown below.

(1) Accelerated weather resistance Using a sunshine weather meter of a Suga tester,
The yellowing degree of the sample was measured after irradiation for 3000 hours in a cycle of black panel temperature of 63 ° C., no rain (120 minutes), and rain (18 minutes).

(2) Volatility of UV absorber The concentration (wt%) of the amount of UV absorber in the UV resistant layer determined by liquid chromatography is added (3 wt%).
The value divided by was taken as the residual rate (%).

(3) Transparency The haze value (%) of the laminated sheet was measured with a haze meter manufactured by Nippon Denshoku Kogyo.

Example 1 (1) Preparation of Resin for UV Resistant Layer Iupilon E-2000 as a polycarbonate resin
97% by weight (trade name, manufactured by Mitsubishi Gas Chemical Co., Inc.) and 3% by weight of Siasorb UV1164 (trade name, manufactured by Cytec) as a triaryltriazine-based UV absorber.
Pre-mix in a tumbler at a ratio of
Pelletized using a shaft extruder (made by Ikegai Iron Works Co., Ltd.).

(2) Preparation and Evaluation of PC Laminated Sheet Using the resin prepared in (1) as the ultraviolet ray resistant layer raw material,
As a polycarbonate resin for substrate layers, Iupilon E-
Using 2000 U (trade name, manufactured by Mitsubishi Gas Chemical Co., Inc.), a weather resistant PC laminated sheet was produced by the coextrusion method. That is, the substrate layer raw material is extruded using a 65 mm extruder, while the ultraviolet resistant layer raw material is extruded using a 30 mm extruder,
Using a multi-manifold type die, a laminated sheet of 2 types and 2 layers (laminated sheet thickness: 2 mm, UV resistant layer thickness:
About 50 μm) was prototyped. Table 1 shows the results of accelerated weather resistance evaluation of this laminated sheet.

Comparative Example 1 The procedure of Example 1 was repeated, except that the benzotriazole-based ultraviolet absorber Siasorb UV5411 (trade name, molecular weight 323.4, manufactured by Cytec) was used as the ultraviolet absorber.

Comparative Example 2 The procedure of Example 1 was repeated, except that the benzotriazole type ultraviolet absorber ADEKA STAB LA-31 (trade name, molecular weight 659, manufactured by Asahi Denka Kogyo Co., Ltd.) was used as the ultraviolet absorber. The results are shown in Table 1.

Comparative Example 3 A polycarbonate resin alone was used without providing an ultraviolet resistant layer.
A mm-thick sheet was prepared and evaluated. The results are shown in Table 1.

[0025]

EFFECTS OF THE INVENTION According to the present invention, sufficient ultraviolet resistance can be obtained with an addition amount of less than half that of conventional ultraviolet absorbers, which leads to cost reduction, and also causes a decrease in physical properties and coloring and other defective phenomena. Is reduced. Further, it becomes possible to reduce the volatilization of the ultraviolet absorbent, which has been a problem so far, and it is possible to suppress contamination of the cooling roll and the working environment.

Table 1 Example 1 Comparative example 1 Comparative example 2 Comparative example 3 Accelerated weathering yellowing 1.5 1.5 13.2 14.2 24.5 Volatile residual rate of ultraviolet absorber (% 96 90 94- Transparency Haze value (%) 0.3 0.3 0.3 0.3

Claims (3)

[Claims] 1. A polycarbonate resin composition containing a triaryltriazine compound represented by the following general formula (1) in an amount of 0.1 to 10% by weight based on the polycarbonate resin. Embedded image (In the formula, R represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a halogen atom or an alkyl group having 2 to 6 carbon atoms substituted with an alkoxy group having 1 to 15 carbon atoms, or a benzyl group; 'Represents a methyl group.) 2. A molded product comprising the polycarbonate resin composition according to claim 1. 3. A polycarbonate resin sheet and a laminate in which an ultraviolet resistant layer is provided on one or both sides of the film, wherein the ultraviolet resistant layer is coated with the polycarbonate resin composition according to claim 1 to a film thickness of 10 to 100 μm. UV-resistant polycarbonate resin sheets and films characterized by: