JPH08156120A - Manufacture of weather-resistant polycarbonate sheet - Google Patents

Abstract

PURPOSE: To obtain a sheet which is excellent in weather resistance excellently in film thickness without impairing intrinsic features of a polycarbonate resin by a method wherein a polycarbonate sheet is extruded from a sheet extruder having a cooling roll of a vertical placed type, and a film for a surface layer containing a specified amount of an ultraviolet absorbing agent is thermally laminated from above a bank. CONSTITUTION: A polycarbonate sheet is ordinarily obtained as follows; a polycarbonate resin extruded from an extruder 1 via a die 2 is cooled to be solidified in a sheet shape with a cooling roll 3, taken off with a take-off roll 8, and cut with a cutting machine. Further, when the polycarbonate resin is pressed in a sheet-shape with the cooling roll 3, a film for a surface layer 5 containing at least 1wt.% of an ultraviolet absorbing agent is inserted from above a bank, thermally laminated on the sheet, and a weather resistant polycarbonate laminated sheet 9 can be obtained. Further, since the film for the surface layer 5 is difficult to be elongated and easy to be wrinkled, tension of the film is controlled with an auxiliary roll 7 in order to make the film difficult to be wrinkled.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polycarbonate having excellent weather resistance which 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 method for manufacturing a sheet and a 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, the ultraviolet rays cause the polycarbonate resin surface to turn yellow, causing fine cracks and causing a decrease in strength. . As a countermeasure against this, a sheet having a weather-resistant surface has been developed.

As a method for weather-proofing the surface of the sheet,
There are a method of laminating an acrylic resin and a method of laminating with a polycarbonate resin itself. In these methods, 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 of laminating an acrylic resin, there are a method of thermally laminating an acrylic film at the time of sheet production, a method of applying an acrylic paint after the sheet production, and a method of coextrusion molding an acrylic resin and a polycarbonate resin (Japanese Patent Publication No. 47-19119, JP-A-55-
No. 59929). On the other hand, generally, co-extrusion molding is adopted for laminating polycarbonate resins (Japanese Patent Publication No. 3-54626).

[0004]

When the surface of a polycarbonate sheet is coated with an acrylic resin, whitening occurs when the acrylic layer is immersed in warm water due to moisture absorption, whitening due to stretching of the acrylic layer in the cold-folded portion, and reduction in impact strength. However, problems such as roughening of the acrylic surface during thermoforming occur. In addition, when acrylic resin and polycarbonate resin are mixed, it becomes cloudy, so when recycling the ear material or end material derived from the sheet manufacturing or the sheet itself, it cannot be reused as a transparent resin, thus increasing the loss and increasing the cost. There is a problem that leads to.

In the method of laminating a polycarbonate resin containing a large amount of an ultraviolet absorber on the surface layer of a sheet by coextrusion molding, it is difficult to make the thickness of the surface layer portion uniform, and particularly, the thickness of the surface layer portion in the width direction is made uniform. Takes time to do
A large amount of loss will occur. Further, in the case of stacking polycarbonate resins, since the refractive index is the same, the interface between the substrate and the surface layer portion cannot be determined, and the thickness of the surface layer portion cannot be measured. Further, since a large amount of the ultraviolet absorber is added to the surface layer, the ultraviolet absorber is volatilized, which pollutes the environment and the cooling roll at the time of extrusion molding, and causes a poor appearance of the sheet. In addition, when performing extrusion molding, a new extruder and a special die or feed block are required, which requires considerable capital investment. Further, in the co-extrusion molding, when the thickness of the surface layer is changed, the inside of the extruder has to be completely replaced, which causes a large amount of loss. An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a weather-resistant polycarbonate sheet, a film and a method for producing the same, which utilize the current sheet extrusion equipment.

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a polycarbonate resin containing a necessary amount of an ultraviolet absorber is thermally laminated at the time of producing a polycarbonate sheet to obtain a polycarbonate resin. The inventors have found that a sheet having excellent weather resistance can be obtained with high accuracy in the film thickness of the surface layer without impairing the original transparency, impact resistance, heat resistance and flame retardancy, and arrived at the present invention.

That is, the present invention is an invention relating to the following (1) to (5). (1) When laminating a surface layer film containing 1% by weight or more of an ultraviolet absorber on one surface of a polycarbonate sheet, first, the polycarbonate sheet is extruded by a sheet extruder having a vertically-oriented cooling roll, and then the upper part of the bank. A method for producing a weather-resistant polycarbonate sheet, which comprises thermally laminating the surface layer film.

(2) When laminating a surface layer film containing 1% by weight or more of an ultraviolet absorber on one side or both sides of a polycarbonate sheet, first, the polycarbonate sheet is extruded by a sheet extruder having a horizontal type cooling roll. Then, a method for producing a weather-resistant polycarbonate sheet, which comprises thermally laminating the surface layer film from one side or both sides of the bank. (3) A polycarbonate resin containing 1% by weight or more of an ultraviolet absorber is produced into a film by an extruder. In this case, after extruding the polycarbonate resin, a rubber roll is pressure-bonded to the cooling roll that comes into contact first to eliminate the adhesion of the ultraviolet absorber to the cooling roll. (4) Polycarbonate sheet UV absorber on one side of % Is a weather-resistant polycarbonate sheet obtained by laminating a surface layer film containing more than 100%, extruding the polycarbonate sheet with a sheet extruder having a vertical-type cooling roll, then, the surface layer film from the top of the bank Weather resistant polycarbonate sheet obtained by heat lamination

(5) A weather-resistant polycarbonate sheet obtained by laminating a surface layer film containing an ultraviolet absorber in an amount of 1% by weight or more on one or both sides of a polycarbonate sheet. A polycarbonate sheet is extruded with a sheet extruder, and then a weather resistant polycarbonate sheet obtained by thermally laminating the surface layer film from one side or both sides of the bank.

By using the above-mentioned method, it becomes possible to manufacture with the existing sheet extrusion equipment, and if films having various performances or colors are prepared in advance, various kinds of laminated sheets can be manufactured during one sheet manufacturing. Therefore, the present invention is suitable for a case where facility investment cannot be performed or a case where a small number of products are manufactured.

In the present invention, the polycarbonate resin used for the surface layer and the substrate is not particularly limited as long as it can be molded into a sheet, and various fillers, stabilizers,
It may contain an antistatic agent, a lubricant, a heat ray shielding agent, a pigment and the like.

The ultraviolet absorber used in the surface layer in the present invention may be a benzotriazole type, a benzophenone type, a salicylic acid phenyl ester type, a triazine type, a metal powder or the like having an ultraviolet absorbing effect, but a polycarbonate resin is preferable. 280-300 that causes the most light deterioration
Those having a high ultraviolet absorption ability in the region of nm and a low volatility are preferable. For example, if a high molecular weight type benzotriazole-based UV absorber having a molecular weight of 400 or more or a triazine-based organic UV absorber having good compatibility with a polycarbonate resin or a metal powder such as titanium oxide or cerium oxide is used,
A polycarbonate resin laminated sheet having good weather resistance, which hardly volatilizes or deposits on the sheet surface during molding, can be obtained. The ultraviolet absorber may be used in combination.

The amount of the ultraviolet absorber added to the surface layer depends on the ultraviolet absorbing ability of the ultraviolet absorber used and the thickness of the surface layer film, but at least 1% by weight or more, preferably 3% by weight or more is required. The thickness of the surface layer film is
There is no particular limitation, and it may be wound on a roll, but for practical use, a range of 30 to 100 μm is preferable. Three
It becomes easy to process polycarbonate resin into a film with a thickness of 0 μm or more, while the thickness is 100 μm.
In the above, the weather resistance improving effect is not significantly improved.

The method for producing the surface layer film of the present invention will be described below with reference to the process drawings, but the present invention is not limited to the following method. For the production of the film for the surface layer, FIG.
The usual film extrusion manufacturing equipment as shown in FIG. That is, after the polycarbonate resin extruded in a film form from the extruder 1 through the die 2 is cooled and solidified by the cooling roll 3, the winding surface layer film 5 is obtained on the winding opening roll 6. When a highly volatile UV absorber is used, the cooling roll 3 that the molten resin first contacts after exiting the die 2 is contaminated by the volatilization of the UV absorber and impairs the appearance of the film. It is necessary to bring the film into close contact with the mirror-finished metal roll 3 with the roll 4. By this method, the ultraviolet absorber does not adhere to the cooling roll 3, and the surface layer film 5 having a good appearance can be obtained.

Next, a method for producing the weather resistant polycarbonate resin laminated sheet of the present invention will be described, but the present invention is not limited to the following method. (1) When using a vertical cooling roll As shown in FIG. 2, a polycarbonate sheet is usually formed by extruding a polycarbonate resin extruded from an extruder 1 through a die 2 into a sheet with a cooling roll 3. It is obtained by cooling and solidifying, taking it with a take-up roll 8 and cutting it with a cutting machine. The present invention further includes a surface layer film when pressing a polycarbonate resin into a sheet with a cooling roll 3. 5 was inserted from the upper part of the bank and heat-laminated on the sheet to obtain a weather resistant polycarbonate laminated sheet 9. During heat lamination, the polycarbonate film is difficult to stretch and wrinkles easily form on the film. Therefore, it is necessary to control the tension of the film by the auxiliary roll 7 to prevent wrinkles from forming on the film. If there are wrinkles, it causes air wrapping and a good product cannot be obtained. Further, when the film 5 is brought into contact with the upper cooling roll 3 for thermal lamination, the film 5
Since air bubbles enter between the cooling roll 6 and the cooling roll 6 and cause a defective appearance during thermal lamination in the bank, the pressure bonding roll 4
It is necessary to bring the film 5 into close contact with the cooling roll 6 by using.

(2) When using a horizontal-type cooling roll On the other hand, when a horizontal-type cooling roll is used, the sagging of the sheet does not occur, so that thermal lamination from one side or both sides is possible. That is, as shown in FIG. 3, when the polycarbonate resin extruded from the extruder 1 through the die 2 is cooled and solidified into a sheet by the horizontal cooling roll 3, the auxiliary roll 7 is used for the surface layer. Polycarbonate film 5
By heat laminating both sides of the bank portion, it is possible to obtain a polycarbonate laminated sheet 9 having weather resistance on both sides.

[0017]

EXAMPLES Next, the present invention will be described more specifically by way of examples. The evaluation and test methods used in this example are shown below. (1) Weather resistance Using the Sunshine Weather Meter of Suga Test Machine,
The yellowing degree of the sample was measured after irradiation for 2000 hours in a cycle of black panel temperature 63 ° C., no rain (120 minutes), and rain (12 minutes). (2) Drop weight impact test The diameter of the tip is 20 mmφ using a Fractal screw from Chast.
The breaking energy when using the weight of No. 2 was measured.

(3) Heat resistance test The appearance and adhesion of the sample after 200 hours at 100 ° C. were evaluated with a hot air circulation dryer. (4) Hot water resistance test The appearance and adhesion of the sample after 200 hours at 75 ° C were evaluated in a constant temperature water bath. (5) Heat cycle test -30 ° C (30 minutes), 80 ° C with Tabai's environmental tester
(30 minutes) The appearance and adhesion of the sample after 100 cycles of 1 cycle and 2 hours were evaluated.

(6) Recyclability The sample was crushed and again made into a 3 mm thick sheet with a sheet extruder, and the transparency was visually evaluated. (7) Cold foldability 150mm square sheet with weatherproof surface facing down and tip 3m
Hold the mR arrow string from the top of the seat and rotate it at an angle of about 1 at room temperature.
It was bent at 25 ° and the presence or absence of whitening at the bent portion was visually confirmed.

(8) Low temperature impact test A sample of 150 mm square sheet bent with the weatherproof surface inside is left at a temperature of 0 to -40 ° C for 1 hour and then taken out with the weatherproof surface facing down. Then, the bent portion of the sample was immediately hit with a plastic hammer (weight: 570 g) to confirm the occurrence of breakage and cracks. Table 1 shows the number of fractures when the test was conducted 5 times.

Example 1 (1) Preparation of surface layer resin Polycarbonate resin as polycarbonate resin (Mitsubishi Gas Chemical Co., Ltd., trade name: Iupilon E-200)
0) 90% by weight, Tinuvin 23 as a UV absorber
4 (trade name, manufactured by Ciba Geigy) was premixed in a tumbler at a ratio of 10% by weight, and further pelletized using a 45 mm twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd.). (2) Preparation of film for surface layer 90 mm shown in FIG. 1 using the pellet prepared in (1)
A film having a thickness of 50 μm was formed using a φ extruder. During the production of the film, when the film came into contact with the first cooling roll, the film was pressure-bonded with a mirror surface rubber roll to prevent the ultraviolet absorber from adhering to the metal roll.

(3) Preparation of weather resistant sheet Polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc., trade name: Iupilon E-2000U) was used as a substrate material, and a polycarbonate sheet was produced by a sheet extruder. The film produced in (2) was heat-laminated from above the cooling roll to obtain a laminated sheet.
FIG. 2 shows a schematic diagram of the weather resistant sheet manufacturing process used in this example. That is, first, the 65 mmφ extruder 1 to the die 2
The polycarbonate resin extruded through the above is formed into a sheet 9 having a width of 450 mm and a thickness of 3 mm by the cooling roll 3. Next, the surface layer film 5 is inserted from the upper part of the bank through the auxiliary roll 1 and heat laminated on a polycarbonate sheet. The laminated sheet was air-cooled, taken up by a take-up roll 8 and cut by a cutting machine to obtain a laminated sheet having a constant shape. The results are shown in Table 1.

Example 2 Example 2 was repeated except that the UV absorber was changed to ADEKA STAB LA-31 (manufactured by Asahi Denka Kogyo KK). The results are shown in Table 1.

Comparative Example 1 Polycarbonate resin alone without coating layer 3 mm
A thick sheet was prepared and evaluated. The results are shown in Table 1.

Comparative Example 2 In the sheet extruding step of the conventional extruder shown in FIG. 4, the laminate polycarbonate roll 11 was used for the polycarbonate sheet after passing through the cooling roll 3, and an attempt was made to thermally laminate the polycarbonate film 10 for the surface layer. It wasn't fused.

Comparative Example 3 In the sheet extrusion step shown in FIG. 4, a 50 μm-thick acrylic film (made by Kanegafuchi Chemical Co.
(Trade name: Sanduren) was heat laminated. Comparative Example 3
The evaluation results of the laminated sheet thus obtained are shown in Table 1.

[0027]

The effects of the present invention are listed below. (1) The inherent transparency of polycarbonate resin,
Weather resistance can be improved while maintaining features such as impact resistance. (2) Whitening does not occur during recycling, which is a problem in the case of a laminated sheet with an acrylic resin. (3) Manufacture is possible with existing polycarbonate sheet extrusion equipment. (4) Only the surface layer can be switched, and the loss is small. (5) A sheet having a highly accurate surface layer can be easily obtained.

Table 1 Example 1 Example 2 Comparative Example 1 Comparative Example 3 Weather Resistance Yellowing Degree 2.8 2.2 15.5 2.2 Drop Weight Impact Strength (J) Weather Resistance Surface 1.4 × 10 ² 1.4 × 10 ² 1.7 × 10 ² 1.5 × 10 ² PC surface 1.5 × 10 ² 1.5 × 10 ² 1.7 × 10 ² 1.4 × 10 ² 100 ° C heat resistance Appearance No change No change No change Slightly cloudy Adhesion ○ ○ − ○ 75 ° C hot water resistance Appearance No change No change Whitening Adhesion ○ ○ − ○ Heat cycle test Appearance No change No change No change No change Adhesion ○ ○ − ○ Recyclability ○ ○ ○ White turbid cold bending property ○ ○ ○ Whitening low temperature impact test 0 ° C 0/50 / 50/5 0 / 5-10 ° C 0/5 0/5 0/5 0 / 5-20 ° C 0/5 0/5 0/5 1 / 5-30 ° C 0/5 0/5 0/5 5 / 5-40 ° C 0/5 0/5 0/5 5/5

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for manufacturing a surface layer film.

FIG. 2 is a schematic view of a laminated sheet manufacturing process using a vertical roll according to the present invention.

FIG. 3 is a schematic view of a laminated sheet manufacturing process using a horizontal roll according to the present invention.

FIG. 4 is a schematic view of a conventional acrylic film laminated sheet manufacturing process.

[Explanation of symbols]

 1: Extruder 2: Die 3: Cooling roll 4: Rubber roll 5: Polycarbonate film for surface layer 6: Winding roll 7: Auxiliary roll 8: Pinch roll 9: Polycarbonate sheet 10: Laminating film 11: Laminating roll

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B32B 31/30 9349-4F // B29K 69:00 B29L 9:00

Claims (6)

[Claims] 1. When laminating a surface layer film containing 1% by weight or more of an ultraviolet absorber on one surface of a polycarbonate sheet, first, the polycarbonate sheet is extruded by a sheet extruder having a vertical type cooling roll, and then, A method for producing a weather-resistant polycarbonate sheet and film, which comprises thermally laminating the surface layer film from the top of the bank. 2. When laminating a surface layer film containing 1% by weight or more of an ultraviolet absorber on one side or both sides of a polycarbonate sheet, first, the polycarbonate sheet is extruded with a sheet extruder having a horizontal type cooling roll, Next, a method for producing a weather resistant polycarbonate sheet and film, which comprises thermally laminating the surface layer film from one side or both sides of the bank. 3. The ultraviolet absorber is produced by extruding the polycarbonate resin into a film by using a polycarbonate resin containing 1 wt% or more of the ultraviolet absorber by an extruder, and then pressing the rubber roll on a cooling roll which first comes into contact with the ultraviolet absorber. A method for producing a polycarbonate sheet and a film, characterized in that the adhesion to the cooling roll is eliminated. 4. The method for producing a polycarbonate sheet and film according to claim 1, wherein the film thickness is 30 to 100 μm. 5. A weather-resistant polycarbonate sheet obtained by laminating a surface layer film containing an ultraviolet absorber in an amount of 1% by weight or more on one side of a polycarbonate sheet, the sheet extruder having a vertical cooling roll. To extrude a polycarbonate sheet, and then heat laminate the film for the surface layer from the upper part of the bank to obtain a weather-resistant polycarbonate sheet and film. 6. A weather-resistant polycarbonate sheet obtained by laminating a surface layer film containing an ultraviolet absorber in an amount of 1% by weight or more on one or both sides of a polycarbonate sheet, which first has a horizontal roll for cooling. A weather resistant polycarbonate sheet and film obtained by extruding a polycarbonate sheet with a sheet extruder and then thermally laminating the film for the surface layer from one side or both sides of the bank.