JP4639876B2 - Polycarbonate resin laminate excellent in weather resistance and method for producing the same - Google Patents

Description

  The present invention relates to a polycarbonate resin laminate excellent in weather resistance. More specifically, the present invention relates to a weather-resistant polycarbonate resin laminate molded by a coextrusion method without impairing the original properties of the polycarbonate resin.

  Polycarbonate resin has excellent transparency, mechanical strength, high heat distortion temperature, and excellent dimensional stability, workability and self-extinguishing properties. in use. However, since the polycarbonate resin is inferior in weather resistance, it has a problem that the impact strength is reduced or yellowed in the case of outdoor use exposed to direct sunlight. As a method for improving these problems, a resin composition in which an ultraviolet absorber is blended with a polycarbonate resin is known. However, it has not been able to solve the problem of reduced impact strength and yellowing when used outdoors for a long time. Moreover, although the laminated body which coat | covered the polycarbonate resin layer with the acrylic resin layer excellent in the weather resistance is disclosed (patent document 1), since the refractive index of both resin differs, the ear | edge and use of a laminated body for the purpose of recycling When the finished laminate was pulverized, melted, kneaded and molded, there was a problem that the transparency was lowered. In addition, a coextruded sheet that prevents a decrease in transparency during recycling by coextruding a polycarbonate resin composition and a polycarbonate resin containing a large amount of an ultraviolet absorber is disclosed (Patent Document 2). In addition, there is a problem that the heat stability of the resin composition in which the ultraviolet absorber is blended with the resin composition and the initial coloration.

  Further, in order to improve the thermal stability reduction and initial coloration of the polycarbonate resin composition containing the ultraviolet absorber, a polycarbonate co-extruded product having a resin composition combined with a specific phosphorus compound and a phenol compound as a surface layer is provided. Although disclosed (Patent Document 3), it has not been possible to solve the problems of a decrease in initial coloring or yellowing after outdoor use for a long time. The base layer portion is a resin composition containing a polyester resin obtained by polycondensation of a polycarbonate resin and / or a dicarboxylic acid-based polycondensation component and a glycol-based condensation component, and the surface layer portion has an average molecular weight of 15,000 to 23, As a resin composition containing 3 to 25 parts by weight of an ultraviolet absorber with respect to 100 parts by weight of polycarbonate resin in the range of 000, a transparent multi-layer resin layered by laminating and integrating a base layer part and a surface layer part by a coextrusion molding method Although the body was disclosed (patent document 4), the compounding rate of the ultraviolet absorber was also high in this case, and it was not satisfactory in terms of thermal stability and initial coloring. Furthermore, in a polycarbonate resin molded article in which a core layer made of a polycarbonate resin and a cover layer made of a polycarbonate resin present on at least one side of the core layer are formed by coextrusion, the cover layer contains a specific triazine-based light stabilizer. A polycarbonate resin molded article made of the added resin composition is disclosed (Patent Document 5), but it is not satisfactory in terms of thermal stability and weather resistance.

Japanese Patent Publication No. 47-018119 JP 55-059929 A Japanese Patent Laid-Open No. 06-31493 JP 2000-238223 A JP 2000-313051 A

  An object of the present invention is to provide a polycarbonate resin laminate having good weather resistance efficiently in a polycarbonate resin laminate containing a high-concentration ultraviolet absorber in the surface layer with the addition of a less ultraviolet absorber.

As a result of repeated earnest research to solve the above problems, even if the mixing ratio of the UV absorber is the same and the discharge rate ratio of the surface layer containing the high concentration UV absorber and the polycarbonate resin core layer is the same It has been found that the weather resistance is remarkably improved by selecting the molding apparatus and molding conditions. That is, in the laminate having excellent weather resistance, at the interface between the polycarbonate resin surface layer containing a high-concentration UV absorber and the polycarbonate resin core layer containing a low-concentration UV absorber (or no UV absorber), The present invention was completed by finding that an ultraviolet absorber layer having a specific concentration gradient exists.
That is, the first gist of the present invention is that an average thickness per one side calculated from a discharge amount of a polycarbonate resin (B) layer containing a high-concentration ultraviolet absorber on at least one surface of the polycarbonate resin (A) layer. Is a layered product laminated by coextrusion so as to be 20 to 100 μm, and a concentration gradient satisfying the following formula (1) in the vicinity of the interface between the (A) layer and the (B) layer of the ultraviolet absorber concentration: It is to provide a held polycarbonate resin laminate (C).

15X ^0.2 ≦ Y ≦ 15X ^0.5 (1)
(In the formula, X is a layer thickness (μm) which is an ultraviolet absorber concentration of ± 10% with respect to an average ultraviolet absorber concentration from the outermost layer of the (B) layer to a depth of 10 μm, and Y is (B ) Gradient gradient from -10% to the average UV absorber concentration from the outermost layer of the layer to the depth of 10 μm to + 10% UV absorber concentration with respect to the average UV absorber concentration of the layer (A). (The layer thickness (μm).)
In this case, the layer (A) may not contain an ultraviolet absorber, but Y in this case is from −10% to the average ultraviolet absorption concentration from the outermost layer of the (B) layer to a depth of 10 μm, (A) The layer thickness (μm) having a gradient concentration gradient until the UV absorber concentration of the layer reaches zero. In addition, the ultraviolet absorber density | concentration in polycarbonate resin in this invention was measured by the postscript method.

  The second gist of the present invention is that when the polycarbonate resin (A) layer and the polycarbonate resin (B) layer containing a high-concentration ultraviolet absorber are coextruded, the polycarbonate resin (A) layer and (B) The (A) layer and the (B) layer are merged at a temperature setting that is 80 ° C. to 180 ° C. higher than the glass transition temperature of the polycarbonate resin constituting the layer, and the die is formed from the merge point of the (A) layer and the (B) layer. It is providing the manufacturing method of the polycarbonate resin laminated body (C) as described in the said 1st summary which makes the distance to an exit 300 mm or more. In this way, in a laminate in which a layer having a specific concentration gradient of the UV absorber exists at the interface between the surface layer and the core layer, the UV absorber gradually bleeds out from the deep part, It is considered that the weather resistance is excellent because a sufficient ultraviolet absorber for suppressing the deterioration of the polycarbonate resin could be secured. In contrast, in a laminate having a concentration gradient layer of a predetermined thickness of the UV absorber, the UV absorber concentrated on the surface layer disappears due to decomposition and bleed out in the initial stage of use, and is relatively early. It is thought that the weather resistance decreases.

  The polycarbonate resin laminate (C) of the present invention has less ultraviolet rays by having an ultraviolet absorber layer having a specific concentration gradient at the interface between the polycarbonate resin surface layer and the polycarbonate resin core layer containing the ultraviolet absorber. Addition of absorbent agent reduces initial coloration, suppresses volatilization of UV absorbers during extrusion molding, and excels in economic efficiency and weather resistance, so it can be used for building materials, CFI molding, PSI molded substrates, etc. that require weather resistance. Can be used for many purposes.

The polycarbonate resin constituting the polycarbonate resin (A) layer and the (B) layer according to the present invention is not particularly limited, and can an aromatic dihydroxy compound or a small amount of the polyhydroxy compound and phosgene be obtained by an interfacial polymerization method? Or a thermoplastic polycarbonate polymer which may be branched by a transesterification reaction between the aromatic dihydroxy compound and the carbonic acid diester, for example, a carbonic acid ester polymer containing bisphenol A as a main raw material. . The molecular weight of the polycarbonate resin to be used is not particularly limited, but those capable of producing a sheet, board, or plate by ordinary extrusion molding are preferred, and the viscosity average molecular weight is 15,000 to 35,000, preferably 20,000 to 31,000, More preferably 23,000 to 30,000. Various commonly used additives may be added to the polycarbonate resin. Examples of the additives include antioxidants, anti-coloring agents, flame retardants, mold release agents, antistatic agents, and dyes and pigments. It is done. Although there is no restriction | limiting in particular in the thickness of a polycarbonate resin (A) layer, 0.2 mm-20 mm are normally employ | adopted as a building-material use for which a weather resistance is requested | required, a CFI shaping | molding, and a PSI shaping | molding board | substrate preferably. There are many cases.
Moreover, as for the thickness of a polycarbonate resin (B) layer, 20-100 micrometers is preferable from a viewpoint of the weather resistance of a polycarbonate resin laminated body (C). If it is less than 20 μm, the effect of improving weather resistance is small, and if it exceeds 100 μm, no further effect of improving weather resistance can be expected, which is economically disadvantageous.

Examples of the ultraviolet absorber added to the polycarbonate resin include benzotriazole-based, benzophenone-based, salicylic acid phenyl ester-based, benzoxazine-based, malonic ester-based, and triazine-based ultraviolet absorbers.
Examples of the benzotriazole ultraviolet absorber include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzo Triazole, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylenebutyl) -6- (2H-benzotriazole -2-yl) phenol] and the like, and as the benzophenone-based ultraviolet absorber, 2-hydroxy-4-octoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4 ′ -Chlorbenzophenone, 2,2-dihydroxy-4-methoxybenzophenone, 2,2-dihydroxy- Examples thereof include 4,4′-dimethoxybenzophenone.

Examples of salicylic acid phenyl ester ultraviolet absorbers include pt-butylphenyl salicylic acid ester.
Examples of the benzoxazine-based ultraviolet absorber include 2,2 ′-(1,4-phenylene) bis [4H-3,1-benzoxazin-4-one].
Examples of the malonic ester ultraviolet absorber include dimethyl [(4-methoxyphenyl) -methylene] malonate.
Examples of triazine ultraviolet absorbers include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-). Ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-) Butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2- Hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazi 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1 , 3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyethoxy) -1,3,5-triazine, etc., but is not limited thereto. And generally available UV absorbers and the like.

  The polycarbonate resin laminate (C) of the present invention has an average per side calculated from the discharge amount of a polycarbonate resin (B) layer containing a high-concentration ultraviolet absorber on at least one surface of the polycarbonate resin (A) layer. Concentration gradient satisfying the formula (1) in the vicinity of the interface between the (A) layer and the (B) layer, which is a laminate laminated by coextrusion so as to have a thickness of 20 to 100 μm. It has a big feature of having. That is, in the formula (1), X is a layer thickness that is an ultraviolet absorber concentration of ± 10% with respect to an average ultraviolet absorber concentration from the outermost layer of the (B) layer to a depth of 10 μm, and Y is ( B) It is a layer thickness having a concentration gradient in a gradient from −10% to + 10% of the average ultraviolet absorber concentration of the layer (A) with respect to the average ultraviolet absorber concentration from the outermost layer of the layer to a depth of 10 μm. Thus, since the ultraviolet absorber concentration has a concentration gradient that satisfies the formula (1) in the vicinity of the interface between the (A) layer and the (B) layer, the ultraviolet absorber gradually bleeds out from the deep part, It is considered that the weather resistance is excellent because a sufficient ultraviolet absorber for suppressing deterioration of the polycarbonate resin on the surface of the laminate was secured over a long period of time.

As for the average ultraviolet absorber density | concentration from the outermost layer of the (B) layer which comprises a polycarbonate resin laminated body (C) to 10 micrometers depth, 1.0-8.0 weight% is preferable. When the UV absorber concentration from the outermost layer of the polycarbonate resin (B) layer to a depth of 10 μm is less than 1.0% by weight, the weather resistance of the polycarbonate resin laminate (C) is insufficient, and 8.0% by weight. If the temperature exceeds the range, not only a further improvement in weather resistance can be expected, but also contamination of the roll at the time of coextrusion molding and appearance defects due to coloring of the laminate may be caused, which is not preferable.
Since the average ultraviolet absorber concentration from the outermost layer of the (B) layer to the depth of 10 μm is substantially the same as the ultraviolet absorber concentration contained in the polycarbonate resin constituting the (B) layer, the ultraviolet absorber concentration is You can choose freely from the range.
Further, the concentration of the ultraviolet absorber contained in the polycarbonate resin constituting the layer (A) can be appropriately selected, but is 0.8% by weight or less in order to maximize the effect of the present invention. .

  Next, the manufacturing method of the polycarbonate resin laminate (C) of the present invention will be specifically described. Generally as an extrusion apparatus used for manufacture of a polycarbonate resin laminated body (C), one main extruder which extrudes a polycarbonate resin (A) layer, and one machine which extrudes a polycarbonate resin (B) layer used as a skin layer Consists of the above sub-extruders, and usually the sub-extruder is smaller than the main extruder. The temperature condition of the main extruder is usually 230 to 290 ° C, preferably 240 to 280 ° C, and the temperature condition of the sub-extruder is usually 220 to 280 ° C, preferably 230 to 270 ° C. In the method of coating the polycarbonate resin (A) layer with the polycarbonate resin (B) layer containing a high-concentration ultraviolet absorber, the ultraviolet absorber concentration is expressed by the above formula (1) in the vicinity of the interface between the (A) layer and the (B) layer. If it is a method which can manufacture the polycarbonate resin laminated body (C) with the density | concentration gradient which satisfies), it will not restrict | limit, Well-known methods, such as a feed block system and a multi-manifold system, can be used.

  The (A) and (B) layers of the molten polycarbonate resin extruded from the extruder are set at a temperature that is 80 to 180 ° C. higher than the glass transition temperature of the polycarbonate resin constituting the (A) and (B) layers. In addition, the dice are passed so that the distance from the joining point of the layers (A) and (B) to the die outlet is 300 mm or more. Here, when the set temperature in the die is less than the glass transition temperature of the polycarbonate resin plus 80 ° C., the viscosity of the polycarbonate resin is too high, and the appearance of the laminate deteriorates, or the interface between the layers (A) and (B) The diffusion phenomenon of the UV absorber across both layers in the vicinity does not proceed and the intended concentration gradient is not formed. Conversely, if the set temperature in the die exceeds the glass transition temperature of the polycarbonate resin plus 180 ° C., the thermal stability of the UV absorber will decrease, or the viscosity of the polycarbonate resin will become too low, making it difficult to mold the laminate. Become. In addition, when the distance from the junction of the (A) layer and the (B) layer to the die outlet is less than 300 mm, the ultraviolet absorber straddling both layers in the vicinity of the interface between the (A) layer and the (B) layer The intended concentration gradient is not formed without the diffusion phenomenon. Although there is no upper limit in particular in the distance from the confluence | merging point of a (A) layer and a (B) layer, and a die exit, if it exceeds 800 mm, a shaping | molding apparatus will enlarge and it will become economically disadvantageous.

  The sheet-like (A) layer and (B) layer that have passed through the die flow into a forming roll (polishing roll) whose surface is mirror-finished or molded to form a bank. This sheet-like molded body is mirror-finished or molded and cooled while passing through the molding roll, thereby forming a laminate. As a forming roll temperature, it is 100-190 degreeC normally, Preferably it is 110-180 degreeC. As the roll, a vertical roll or a horizontal roll can be appropriately used.

  EXAMPLES The present invention will be described in further detail below with reference to examples, but the present invention is not limited thereto.

The evaluation and measurement methods used in this example are shown below.
(1) Ultraviolet absorber concentration in polycarbonate resin: A test piece sliced into a thin film using a Fourier transform infrared spectrophotometer (FT / IR-610 main body and microscope Irtron IRT-30 manufactured by JASCO Corporation) Was stepped from the outermost layer in the depth direction at a pitch of 3 μm, and the concentration gradient was determined from the intensity ratio of the peak derived only from the polycarbonate and the peak derived only from the ultraviolet absorber.
The relationship between the intensity ratio of the peak derived only from the polycarbonate and the peak derived only from the UV absorber and the actual concentration of the UV absorber was determined using the above-mentioned FT- The peak intensity ratio was obtained by the IR method, and a calibration curve was prepared and obtained.
(2) Weather resistance: In accordance with JIS K5400, an accelerated test was conducted for 3000 hours using a carbon arc type sunshine weatherometer. (B) Light was applied from the layer side.
(3) Haze: The haze before and after the weather resistance treatment was measured with a haze meter Σ80-NDH manufactured by Nippon Denshoku Industries Co., Ltd.
(4) Degree of yellowing: The difference in yellow index (YI) before and after the weather resistance treatment, ΔYI, was measured with a color difference meter SM-3-CH manufactured by Suga Test Instruments Co., Ltd.

Example 1
A single-screw extruder with a barrel diameter of 65 mm and a screw L / D = 35 was used as the polycarbonate resin (A) layer extruder, the cylinder temperature was 270 ° C., and the discharge rate was 40 kg / hr. Moreover, the extruder for polycarbonate resin (B) layers containing the ultraviolet absorber used as a coating layer uses a single screw extruder with a barrel diameter of 32 mm and a screw L / D = 32, and is set at a cylinder temperature of 270 ° C. The extrusion was carried out at a discharge rate of 600 g / hr. The feed block set temperature and the die set temperature were 260 ° C. and 280 ° C. when two types of resins were melt-extruded and laminated at the same time. The apparatus used at this time has a distance of 380 mm from the point where the layers (A) and (B) join in the feed block to the die outlet. The layers (A) and (B) layered and integrated in the feed block exit the die and are guided to three mirror-finished polishing rolls. The first roll temperature is 120 ° C and the second roll temperature is 140 ° C. The third roll temperature was set to 180 ° C. After forming the bank at the first roll interval, the second and third rolls were passed. The take-up speed was 0.4 m / min, and the take-up pinch roll speed was 0.6 m / min. The thickness of the obtained laminate (C) was 2.0 mm, the thickness of the layer (B) calculated from the discharge amount was 30 μm, and the evaluation results are shown in Table 1.
In addition, the polycarbonate resin used in Example 1 is Mitsubishi Gas Chemical Co., Ltd. product, Iupilon E-2000 (brand name), viscosity average molecular weight 27,500, and glass transition temperature 147 degreeC. The polycarbonate resin used as the layer (B) has, as a UV absorber, Tinuvin 1577 (trade name) manufactured by Ciba Specialty Chemicals Co., Ltd. [Compound name: 2,4-diphenyl-6- (2-hydroxyphenyl-4-hexyl). Oxyphenyl) 1,3,5-triazine] was added at 2.5% by weight. In addition, the same ultraviolet absorber was blended in the layer (A) at 0.1% by weight.
As shown in Table 1, it was revealed that the polycarbonate resin laminate of the present invention had a small haze and ΔYI after the weathering treatment and was excellent in weather resistance.

Example 2
A single-screw extruder having a barrel diameter of 90 mm and a screw L / D = 35 was used as the polycarbonate resin (A) layer extruder, the cylinder temperature was set to 270 ° C., and the discharge amount was 250 kg / hr. Moreover, the extruder for polycarbonate resin (B) layers containing the ultraviolet absorber used as a coating layer uses a single screw extruder with a barrel diameter of 50 mm and a screw L / D = 32, and is set at a cylinder temperature of 270 ° C. The extrusion was carried out at a discharge rate of 3800 g / hr. The feed block set temperature and the die set temperature were 260 ° C. and 280 ° C. when two types of resins were melt-extruded and laminated at the same time. The apparatus used at this time has a distance of 580 mm from the point where the layers (A) and (B) join in the feed block to the die outlet. The layers (A) and (B) layered and integrated in the feed block exit the die and are guided to three mirror-finished polishing rolls. The first roll temperature is 120 ° C and the second roll temperature is 140 ° C. The third roll temperature was set to 180 ° C. After forming the bank at the first roll interval, the second and third rolls were passed. The take-up speed was 1.4 m / min, and the take-up pinch roll speed was 1.5 m / min. The thickness of the obtained laminate (C) was 2.0 mm, the thickness of the layer (B) calculated from the discharge amount was 30 μm, and the evaluation results are shown in Table 1.
In addition, the polycarbonate resin used in Example 2 is Mitsubishi Gas Chemical Co., Ltd. product, Iupilon E-2000 (brand name), viscosity average molecular weight 27,500, and glass transition temperature 147 degreeC. The polycarbonate resin used as the layer (B) has, as a UV absorber, Tinuvin 1577 (trade name) manufactured by Ciba Specialty Chemicals Co., Ltd. [Compound name: 2,4-diphenyl-6- (2-hydroxyphenyl-4-hexyl). Oxyphenyl) 1,3,5-triazine] was added at 2.5% by weight. In addition, the same ultraviolet absorber was blended in the layer (A) at 0.1% by weight.
As shown in Table 1, it was revealed that the polycarbonate resin laminate of the present invention had a small haze and ΔYI after the weathering treatment and was excellent in weather resistance.

Example 3
Molding was performed under the same conditions as in Example 2 except that the discharge amount of the (B) layer extruder was changed so that the thickness of the (B) layer was 50 μm. The evaluation results are shown in Table 1.

Comparative Example 1
A single-screw extruder with a barrel diameter of 65 mm and a screw L / D = 35 was used as the polycarbonate resin (A) layer extruder, the cylinder temperature was 270 ° C., and the discharge rate was 40 kg / hr. Moreover, the extruder for polycarbonate resin (B) layers containing the ultraviolet absorber used as a coating layer uses a single screw extruder with a barrel diameter of 32 mm and a screw L / D = 32, and is set at a cylinder temperature of 270 ° C. The extrusion was carried out at a discharge rate of 600 g / hr. The feed block set temperature was 220 ° C. and the die set temperature was 260 ° C. when two types of resins were melt extruded and laminated at the same time. The apparatus used at this time has a distance of 380 mm from the point where the layers (A) and (B) join in the feed block to the die outlet. The layers (A) and (B) layered and integrated in the feed block exit the die and are guided to three mirror-finished polishing rolls. The first roll temperature is 120 ° C and the second roll temperature is 140 ° C. The third roll temperature was set to 180 ° C. After forming the bank at the first roll interval, the second and third rolls were passed. The take-up speed was 0.4 m / min, and the take-up pinch roll speed was 0.6 m / min. The thickness of the obtained laminate (C) was 2.0 mm, the thickness of the layer (B) calculated from the discharge amount was 30 μm, and the evaluation results are shown in Table 1.
In addition, the polycarbonate resin used by the comparative example 1 is Mitsubishi Gas Chemical Co., Ltd. product, Iupilon E-2000 (brand name), the viscosity average molecular weight 27,500, and the glass transition temperature 147 degreeC. The polycarbonate resin used as the layer (B) has, as a UV absorber, Tinuvin 1577 (trade name) manufactured by Ciba Specialty Chemicals Co., Ltd. [Compound name: 2,4-diphenyl-6- (2-hydroxyphenyl-4-hexyl). Oxyphenyl) 1,3,5-triazine] was added at 2.5% by weight. In addition, the same ultraviolet absorber was blended in the layer (A) at 0.1% by weight.
As shown in Table 1, in the polycarbonate resin laminate of Comparative Example 1, the haze and ΔYI after the weather resistance treatment were larger than those of the Examples, and the weather resistance was inferior even if the thickness of the (B) layer was the same. It was.

Comparative Example 2
A single-screw extruder with a barrel diameter of 65 mm and a screw L / D = 35 was used as the polycarbonate resin (A) layer extruder, the cylinder temperature was 270 ° C., and the discharge rate was 40 kg / hr. Moreover, the extruder for polycarbonate resin (B) layers containing the ultraviolet absorber used as a coating layer uses a single screw extruder with a barrel diameter of 32 mm and a screw L / D = 32, and is set at a cylinder temperature of 270 ° C. The extrusion was carried out at a discharge rate of 600 g / hr. The multi-manifold die set temperature when melt-extruding and laminating two kinds of resins was 260 ° C. In the apparatus used at this time, the distance from the point where the (A) layer and the (B) layer merge in the multi-manifold die to the die outlet is 120 mm. The layers (A) and (B) layered and integrated in the multi-manifold die exit the die and are guided to three mirror-finished polishing rolls. 140 degreeC, 3rd roll temperature was set to 180 degreeC. After forming the bank at the first roll interval, the second and third rolls were passed. The take-up speed was 0.4 m / min, and the take-up pinch roll speed was 0.6 m / min. The thickness of the obtained laminate (C) was 2.0 mm, the thickness of the layer (B) calculated from the discharge amount was 30 μm, and the evaluation results are shown in Table 1.
In addition, the polycarbonate resin used by the comparative example 2 is Mitsubishi Gas Chemical Co., Ltd. product, Iupilon E-2000 (brand name), the viscosity average molecular weight 27,500, and the glass transition temperature 147 degreeC. The polycarbonate resin used as the layer (B) has, as a UV absorber, Tinuvin 1577 (trade name) manufactured by Ciba Specialty Chemicals Co., Ltd. [Compound name: 2,4-diphenyl-6- (2-hydroxyphenyl-4-hexyl). Oxyphenyl) 1,3,5-triazine] was added at 2.5% by weight. In addition, the same ultraviolet absorber was blended in the layer (A) at 0.1% by weight.
As shown in Table 1, in the polycarbonate resin laminate of Comparative Example 2, the haze and ΔYI after the weather resistance treatment were larger than those of the Examples, and the weather resistance was inferior even if the thickness of the (B) layer was the same. It was.

Claims (4)

By coextrusion so that the average thickness per one side calculated from the discharge amount of the polycarbonate resin (B) layer containing a high-concentration ultraviolet absorber on at least one surface of the polycarbonate resin (A) layer is 20 to 100 μm. A laminated laminate comprising a polycarbonate resin laminate excellent in weather resistance having a concentration gradient satisfying the following formula (1) in the vicinity of the interface between the (A) layer and the (B) layer of the ultraviolet absorber. (C).
15X ^0.2 ≦ Y ≦ 15X ^0.5 (1)
(In the formula, X is a layer thickness (μm) which is an ultraviolet absorber concentration of ± 10% with respect to an average ultraviolet absorber concentration from the outermost layer of the (B) layer to a depth of 10 μm, and Y is (B ) Gradient gradient from -10% to the average UV absorber concentration from the outermost layer of the layer to the depth of 10 μm to + 10% UV absorber concentration with respect to the average UV absorber concentration of the layer (A). (The layer thickness (μm).) The polycarbonate resin laminate (C) excellent in weather resistance according to claim 1, wherein the average ultraviolet absorber concentration from the outermost layer of the polycarbonate resin (B) layer to a depth of 10 µm is 1.0 to 8.0 wt%. The polycarbonate resin laminate (C) excellent in weather resistance according to claim 1, wherein the polycarbonate resin constituting the polycarbonate resin (A) layer and the (B) layer has a viscosity average molecular weight of 23,000 to 30,000. When coextruding the polycarbonate resin (A) layer and the polycarbonate resin (B) layer containing a high-concentration ultraviolet absorber, the glass transition temperature of the polycarbonate resin constituting the polycarbonate resin (A) layer and the (B) layer Further, the (A) layer and the (B) layer are merged at a temperature setting higher by 80 ° C. to 180 ° C., and the distance from the merge point of the (A) layer and the (B) layer to the die exit is 300 mm or more. The manufacturing method of the polycarbonate resin laminated body (C) excellent in the weather resistance in any one of 1-3.