JPH0671832A - Polycarbonate resin laminate for noise barrier - Google Patents

Abstract

PURPOSE:To obtain a laminate, prominent in transparency, resistance to shock, resistance to climate and fire retardance while never losing transparency even when the laminate is recycled to use it. CONSTITUTION:A polycarbonate resin laminate for a noise barrier is constituted of a substrate layer consisting of polycarbonate resin and coating layers, applied on both surfaces of the substrate layer and constituted of polycarbonate resin containing ultraviolet-ray absorbing agent with a density satisfying a formula; thickness (mum) of the coating layer X density (wt.%) of ultraviolet ray absorbing agent = 60-600.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycarbonate resin laminate for a soundproof wall, which is excellent in transparency, impact resistance, weather resistance and flame retardancy and does not impair transparency even when recycled.

[0002]

2. Description of the Related Art In recent years, the development of automobile road networks such as highways and bypass roads has become remarkable in Japan. In addition, the rapid increase in the number of industrial vehicles due to the increase in economic activities and the spread of just-in-time systems has been accompanied by a social situation in which the growth rate of the number of privately-owned passenger cars in the population is high. It was In other words, the reality is that a large number of various automobiles pass by on the roads dedicated to automobiles all over the country. Therefore, the noise caused by road traffic is a very important problem, and it seems that it has become more serious than before.

In addition, with the extension of the Shinkansen network and especially the recent speeding up of conventional lines (for example, the so-called mini Shinkansen of Yamagata Line), the noise caused by railways has become wider and more serious than before. It can be said that there is a tendency. For such noise caused by road traffic and railway, comprehensive and social reforms such as reforming the logistics system, reviewing the location and structure of roads and railways, and reducing the noise of the vehicle itself (engine, wheels, vibration), etc. However, a relatively widespread measure is to install a soundproof wall beside the road / railway. Generally, aluminum plate (perforated plate), galvanized steel sheet (back surface sound insulation plate), glass wool or rock wool (sound absorbing material) has been used as the material of the sound insulation wall. Is excellent in soundproofing, but not transparent. On the other hand, recently, securing the lighting of private houses near the road,
Alternatively, there is a demand for the walls to be made of transparent materials, such as the scenery on the roads around tourist sites should be visible. As the transparent material, a polycarbonate resin plate is said to be suitable due to the demand for mechanical strength and flammability, and in fact, a soundproof wall panel incorporating a polycarbonate transparent plate is beginning to be used partially.

Polycarbonate resin is excellent in transparency, impact resistance, heat resistance, flame retardancy, etc., and is therefore used for construction materials such as domes and arcades, road materials such as wainscots,
It is widely used as materials for molded sundries such as windshields, signs, and curved mirrors, and it is expected that its applications will continue to expand.
However, for a soundproof wall used outdoors, it is particularly important that the weather resistance is excellent, but generally the weather resistance of a polycarbonate resin is inferior to, for example, an acrylic resin, and yellowing or occurs when exposed to the outdoors. There is a problem that whitening and devitrification are likely to occur.

Therefore, various studies have been made to improve the weather resistance of polycarbonate. For example, a polycarbonate resin base material is coated with an acrylic resin which is more excellent in weather resistance than the polycarbonate resin base material, and further, for protection of the base material. A method has been reported in which an ultraviolet absorber is added to an acrylic resin to effectively block ultraviolet rays. (For example, Japanese Patent Publication 47-1911
No. 9, JP-B-55-27848, JP-A-55
-59929).

[0006]

[Problems to be Solved by the Invention] By these methods,
Although the weather resistance of polycarbonate resin can certainly be improved, it is possible to mix it with raw materials such as selvages derived from the production of laminated boards and the end materials generated during the processing of laminated soundproof walls, and to make effective use of it. When trying to recycle the soundproof laminate itself, it is incompatible with the polycarbonate resin of the substrate layer and the acrylic resin of the coating layer, so it becomes cloudy during mixing and cannot be reused as a transparent resin. Problems have surfaced.

The present invention solves the above-mentioned problems associated with the polycarbonate resin plate for a soundproof wall, and therefore has excellent transparency, impact resistance, weather resistance and flame retardancy, and is transparent even when recycled. It is intended to provide a polycarbonate resin laminated plate for a soundproof wall that does not impair the above.

[0008]

The present inventors have provided a polycarbonate resin coating layer containing a specific amount of an ultraviolet absorber on both sides of a polycarbonate resin substrate layer, so that the transparency, impact resistance, heat resistance The present invention has been completed by finding that the requirements for severe weather resistance required for a soundproof wall are sufficiently satisfied without impairing the heat resistance and flame retardancy, and that the laminated plate can be recycled and used. is there.

That is, according to the present invention, a substrate layer made of a polycarbonate resin and a coating layer thickness (μm) × ultraviolet absorber concentration (wt%) on both sides of the substrate layer = 60 to 600.
And a coating layer made of a polycarbonate resin containing an ultraviolet absorber at a concentration satisfying the above condition. As the polycarbonate resin in the present invention, a polymer derived from a divalent phenol compound represented by bisphenol A is used. The method for producing the polycarbonate resin is not particularly limited, and any one produced by the phosgene method, the transesterification method or the solid phase polymerization method can be used. Although the molecular weight is not particularly limited, a gel permeation chromatography method (GPC method) is used from the viewpoint of producing a sheet having a desired thickness by extrusion molding and thermoforming this to manufacture a vending machine front plate. ,
The weight average molecular weight obtained from a calibration curve using monodisperse polystyrene as a standard is preferably 20,000 to 70,000, and particularly preferably 30,000 to 60,000. Further, the polycarbonate resin of the substrate layer and the coating layer in the present invention may be of the same grade or different in molecular weight.

The substrate layer of the present invention is made of the polycarbonate resin as described above, but various antioxidants may be added in order to improve the heat decomposability and heat colorability during molding. Of course, it is possible to mix various ultraviolet absorbers. It is also possible to add an organic or inorganic dye or a brewing agent for coloring.

The coating layer in the present invention is made of polycarbonate.
It consists of a resin and an ultraviolet absorber. Here, when a UV absorber having a molecular weight of 400 or more is used, the UV absorber has a high boiling point and is unlikely to volatilize, and is unlikely to scatter during high temperature molding. Can be improved. In addition, the migration from the thin coating layer to the substrate layer is particularly small, and since it is difficult to deposit on the surface of the laminate, the amount of the ultraviolet absorber contained is maintained for a long time, and the durability of the weather resistance improving effect is excellent. From the point of, it is preferable. Examples of the ultraviolet absorber include benzotriazole-based, 2-hydroxybenzophenone-based, and salicylic acid phenyl ester-based ones. For example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2
-[2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2
Triazoles such as-(3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'- Examples thereof include benzophenones such as dihydroxy-4-methoxybenzophenone. In particular, as an ultraviolet absorber having a molecular weight of 400 or more, 2- [2-hydroxy-3,5
-Bis (α, α-dimethylbenzyl) phenyl] -2-
Benzotriazole, 2,2-methylenebis [4-
Benzotriazoles such as (1,1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6,6-tetramethyl-
4-piperidyl) sebacate, bis (1,2,2,6)
Hindered amines such as 6-pentamethyl-4-piperidyl) sebacate, and further bis (1,2-bis (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate 2,2,6,6-Pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-Di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2
Hinder in the molecule such as 6,6-tetramethylpiperidine
Examples thereof include a hybrid type having both a dophenol and a hindered amine structure, and these can be used alone or in combination of two or more kinds. Among these, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,
3,3-Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is preferred, and the latter is particularly preferred.

The present invention makes it possible to reduce the amount of the ultraviolet absorber with respect to the entire resin plate and to effectively improve the weather resistance of the polycarbonate base layer by concentrating the ultraviolet absorber in the coating layer. The greatest feature is where you can do it. Polycarbonate simply added with UV absorber
When the resin is molded into a board, the weather resistance cannot be improved unless the amount of UV absorber is extremely increased, resulting in problems such as reduced transparency, yellow coloring peculiar to the UV absorber, and reduced mechanical strength. Not practical.

The concentration of the ultraviolet absorber contained in the coating layer of the present invention needs to satisfy the thickness (μm) of coating layer × ultraviolet absorber concentration (wt%) = 60 to 600. Within the range that satisfies this condition, the concentration of the ultraviolet absorber and the thickness of the coating layer are determined so that the substrate layer can be effectively shielded from ultraviolet rays, and also considering the remaining amount of the ultraviolet absorber after heat molding. Just do it. That is, if the coating layer is thick, the concentration of the ultraviolet absorber in the coating layer is relatively low, and if the coating layer is thin, the concentration must be high. When the numerical value of the thickness (μm) of coating layer × concentration of ultraviolet absorber (% by weight) is less than 60, the weather resistance of the obtained front plate is insufficient. On the other hand, when it exceeds 600, the weather resistance improving effect is significantly different. Not only that, but the mechanical strength is rather lowered, and the coating layer becomes colored unique to the ultraviolet absorber, both of which are not preferable. As an example, when a polycarbonate resin containing 5% by weight of an ultraviolet absorber is used as a coating layer having a thickness of 40 μm, the product is 200.

The thickness of the coating layer of the present invention is selected so as to satisfy the above-mentioned conditions, but for practical use, it is preferably in the range of 10 to 100 μm, more preferably in the range of 20 to 80 μm. When the thickness of the coating layer is less than 10 μm, it is difficult to uniformly coat the substrate layer, while even if the coating layer is provided over 100 μm, not only the weather resistance improving effect is not significantly improved, but also the mechanical strength of the plate is increased. It is not preferable because the mechanical strength is lowered.

In forming the coating layer of the present invention,
It is preferable to mix the polycarbonate resin and the ultraviolet absorber in advance. The mixing method is not particularly limited, a method of dry blending with a drum drum blender, a Henschel mixer, etc., a method of pelletizing through a extruder after mixing, or a polycarbonate resin using an extruder. While extruding, it is possible to use any method such as injecting the ultraviolet absorber into the extruder with a metering pump and mixing inside.

Further, various antioxidants may be added to the coating layer of the present invention in order to improve the heat decomposability and heat colorability during molding. It is also possible to add an antistatic agent to give the front plate antistatic performance. The overall thickness of the polycarbonate resin laminate for a soundproof wall comprising the substrate layer and the coating layer of the present invention is generally 1 to 20 mm, and a thickness of 2 to 15 mm is preferable from the viewpoint of soundproofing effect, mechanical strength and cost.

There is no particular limitation on the method for producing the polycarbonate resin laminate for a soundproof wall, which comprises the substrate layer and the coating layer of the present invention. For example, a co-extrusion method in which the raw material resins of the substrate layer and the coating layer are simultaneously melt-extruded to form a sheet, a method of melt-extruding the raw material resin of the coating layer from a T-die and laminating it onto an extruded polycarbonate resin substrate layer, A method of continuously laminating a film-shaped coating layer on a polycarbonate resin substrate layer between heating rolls, a sheet-shaped polycarbonate resin substrate layer and a film-shaped A general manufacturing method is to manufacture a polycarbonate resin laminated plate by using a method such as thermocompression bonding of the coating layer thus formed with a press.

In the production of a laminated plate, the coextrusion method is excellent in that the fluidity of both layers can be matched and made uniform at the time of lamination, so that the adhesion between both layers is good and the molding distortion is similar. ing. In this co-extrusion method, two or three ordinary extruders are used, the substrate layer is melt-extruded from a large extruder such as 60 mmφ or 90 mmφ, and the coating layer is melt-extruded from a small extruder such as 30 mmφ or 40 mmφ. The thickness of the substrate layer and the coating layer can be controlled by adjusting the extrusion amount of two or three extruders and the distance between the rolls of the polishing roll on the exit side of the extruder. Further, it is necessary to match the fluidity with the substrate layer and the coating layer, and this can be performed by adjusting the temperature of each extruder and die.

[0019]

EXAMPLES The effects of the present invention will be more specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The evaluation and test methods used in each example and comparative example are shown below. (1) Haze Using an integrating sphere type haze meter, the haze of a test piece having a thickness of 3 mm at 23 ° C was measured. (2) Yellowness (YI) The yellowness of a test piece having a thickness of 3 mm was measured based on JIS K7103. (3) Drop Weight Impact Strength A steel ball having a weight of 5 kg was dropped from a height of 5 m, and it was observed whether or not the laminated plate was cracked, pierced or scattered. (4) Weather resistance Sunshine weather meter (hereinafter referred to as S
After irradiating for 1000 hours under the condition that a cycle of no sunshine (2 hours) and no rain (18 minutes) is repeated, using a sunshine super long life carbon (WOM) for a temperature of 62 ° C. The sample was evaluated for yellowness. (5) Flame retardancy Based on UL94 standard, the flammability in the vertical test was judged, and in the case of failure, the flammability in the horizontal test was further judged. (6) Recyclability The laminated plate was crushed and extruded and granulated at 270 ° C. using a twin-screw extruder with a 30 mmφ vent (manufactured by Nakatani Machinery, type A). The pellets obtained are compression molded to 3 m
An m-plate was prepared and its transparency was visually evaluated.

[0020]

Example 1 (1) Preparation of Resin for Coating Layer 95% by weight of "Makrolon # 3103" manufactured by Bayer Co., Ltd. as a polycarbonate resin, and 5 "MARK LA-31" manufactured by Asahi Denka Kogyo Co., Ltd. as an ultraviolet absorber. The mixture was premixed in a drum blender at a weight percentage of 270 using a 30 mm vented twin-screw extruder (Nakatani Machine, A type).
Extruded and granulated at ℃. (2) Preparation and Evaluation of Laminated Plate The resin prepared in (1) was used as the raw material for the coating layer, and "Makrolon # 3103" was used as the raw material for the substrate layer to form a laminated plate by the coextrusion method.

That is, for the substrate layer, the barrel diameter 110
mm, screw L / D = 32 extruder was used to extrude at a cylinder temperature of 280 ° C., while for the coating layer,
Extrusion was performed at a cylinder temperature of 270 ° C. using an extruder having a barrel diameter of 30 mm and a screw L / D = 32, and a coating layer was provided on both sides of the base layer using a feed block type die (temperature 270 ° C.). Three-layered laminated sheet (length 200
0 mm, width 1000 mm) was manufactured as a prototype. The thickness of the laminated plate was adjusted at intervals of polishing rolls with a target of 3 mm. The thickness of the coating layer was determined by first pouring the colored coating layer resin and then extruding the original non-colored coating layer resin when the discharge amount of each extruder was adjusted to a predetermined thickness. The structure of this laminate is shown in Table 1.

The transparency, impact resistance, weather resistance, and
Table 1 shows the results of evaluation of flame retardancy and recyclability.

[0023]

Examples 2 to 6 Amount of UV absorber incorporated in the coating layer,
Example 1 was repeated except that the thickness of the coating layer was changed as shown in Table 1. The results are shown in Table 1.

[0024]

[Example 7] "KN-13" manufactured by Teijin Chemicals as a base layer raw material
Example 1 was repeated except that "00" was used. The results are shown in Table 1.

[0025]

[Comparative Example 1] An extruded plate was prepared using a polycarbonate resin alone without providing a coating layer and evaluated. The results are shown in Table 2.

[0026]

[Comparative Examples 2 to 3] Except that the kind and amount of the ultraviolet absorber compounded in the coating layer and the thickness of the coating layer were changed as shown in Table 2,
It carried out like Example 1. The results are shown in Table 2.

[0027]

[Comparative Example 4] As a coating layer material, "Dell Powder 70H" manufactured by Asahi Kasei Co., Ltd., which is a general acrylic resin, was used as an ultraviolet absorber "MAR".
The same procedure as in Example 1 was carried out except that pellets containing 3% of KLA-31 ”were mixed and kneaded. The results are shown in Table 2.

[0028]

[Comparative Example 5] 80% by weight of a general acrylic resin ("Delpowder-70H" manufactured by Asahi Kasei) and 20% by weight of acrylic rubber ("Delpowder-SR" manufactured by Asahi Kasei) were premixed in a drum blender, and further 30 mm with a vent 2 A shock-resistant acrylic resin sheet having a thickness of 3 mm was produced by extruding from a T-die at 260 ° C. using a shaft extruder (manufactured by Nakatani Machinery, type A). The evaluation results are shown in Table 2.

[0029]

[Comparative Example 6] A flame retardant (Daibachi) was added to 100 parts by weight of a resin composed of 80% by weight of a general acrylic resin ("Delpowder-70H" manufactured by Asahi Kasei) and 20% by weight of acrylic rubber ("Delpowder-SR" manufactured by Asahi Kasei). The same procedure as in Comparative Example 6 was carried out except that 15 parts of “CR900” manufactured by Kagaku Kogyo Co., Ltd. was blended in. The evaluation results are shown in Table 2.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

Industrial Applicability According to the present invention, it is possible to provide a polycarbonate resin laminated plate for a soundproof wall, which is excellent in transparency, impact resistance, weather resistance and flame retardancy and does not impair transparency even when recycled.

Claims (1)

[Claims] 1. A substrate layer made of a polycarbonate resin, and a polycarbonate containing an ultraviolet absorber at a concentration satisfying a thickness (μm) of coating layer × ultraviolet absorber concentration (wt%) = 60 to 600 on both sides of the substrate layer. A polycarbonate resin laminate for a soundproof wall, comprising a resin coating layer.