JPH0839746A - Polycarbonate resin laminated plate and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide, at low cost, a thick polycarbonate resin laminated plate which is transparent and has excellent see-through property, can be bent with heat, and useful for window and water tank of vehicle, ship, and aircraft. CONSTITUTION:A polycarbonate resin laminated plate having a thickness of 5-30mm is formed by sticking together two or more of polycarbonate resin sheets with a light curing adhesive which can be cured by near ultraviolet rays having a wavelength of 320-800nm or visible rays.

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 and a method for producing the same. More specifically, the present invention relates to a polycarbonate resin laminated plate, which is useful for windows of vehicles, ships, aircraft, etc., large water tanks such as aquariums, etc., in which two or more polycarbonate resin sheets are pasted together with a photo-curing adhesive, and a manufacturing method thereof is there.

[0002]

2. Description of the Related Art Conventionally, glass sheets have been used for windows of vehicles such as Shinkansen and cars, ships and aircraft, and aquariums of aquariums. However, since a thick material is used from the viewpoint of safety, it becomes heavy and there is a problem in economical efficiency such as installation workability and fuel consumption. Recently, in order to reduce the weight, use of a synthetic resin plate, particularly a polycarbonate resin plate having excellent transparency and impact resistance, has been attracting attention in place of the glass plate. However, since the polycarbonate resin plate has a lower rigidity than the glass plate, it is necessary to increase the thickness of the plate in order to suppress bending during use when it is used for windows or water tanks of vehicles, ships, aircrafts, etc. .

A melt extrusion method is generally used for producing a polycarbonate resin plate. The melt extrusion method is to extrude a molten polycarbonate resin into a plate shape from a T die,
This is a method of forming into a plate shape by sandwiching it between rolls or the like. The thickness of the polycarbonate resin plate is adjusted to a predetermined value by adjusting the discharge amount of the molten resin, the lip gap of the T die, the gap of the roll, and the take-up speed.
It is possible to manufacture plates with a thickness of 0.5 to 15 mm. However, in this manufacturing method, as the thickness of the plate increases, waviness is likely to occur on the plate surface due to cooling spots and the like, and thus the obtained thick plate looks distorted when the background is seen through the plate. However, there is a problem that the so-called transparency is significantly impaired. In particular, when the plate thickness is 10 mm or more, this defect is strong, and it is extremely difficult to produce a polycarbonate resin plate that can be used for the above-mentioned applications by the melt extrusion method.

As a method for producing a thick plate of polycarbonate resin, a method is known in which a plurality of relatively thin sheets obtained by the melt extrusion method are stacked and thermocompression bonded. According to this method, it is possible to obtain a polycarbonate resin plate having a thickness of 10 mm or more. However, since the equipment becomes large-scale, the manufacturing cost becomes extremely high, and it is difficult to obtain a polycarbonate resin plate having good transparency.
As a method of manufacturing a thick plate of a polycarbonate resin, a method of adhering and laminating a plurality of relatively thin sheets with an adhesive has also been studied. Even in the method for producing a polycarbonate resin plate by this bonding method, there are some technically difficult problems due to the adhesive, and a useful polycarbonate resin plate has not been obtained. That is, when a heat-curable adhesive is used, the heat-curing step takes time, resulting in high cost, and there is a problem that the polycarbonate resin plate is warped by heating. An ultraviolet curable adhesive is known as an adhesive that solves the drawbacks of the heat curable adhesive. However, there are some problems in the production of a laminated board using this ultraviolet curable adhesive. That is, in the ultraviolet region where ordinary ultraviolet curable adhesives are cured, the polycarbonate resin is easily decomposed and colored, and a beautiful product cannot be obtained. Furthermore, the polycarbonate resin itself has the property of absorbing ultraviolet rays,
Even if the above-mentioned polycarbonate resin sheet is attempted to be adhered, the strength of ultraviolet rays reaching the adhesive layer is weakened, the adhesive is hard to be sufficiently hardened, and it is difficult to obtain a laminate having an adhesive strength that can be practically used. As described above, it is very difficult to obtain a polycarbonate resin laminated plate which is practically satisfactory by the method using the ordinary adhesive. Further, in the polycarbonate resin laminated plate with such an adhesive, when heated to a temperature of about 160 ° C., innumerable bubbles are generated in the adhesive layer to deteriorate transparency and transparency. Therefore, it cannot be heated and bent, and it is difficult to use it for a window having a curved surface.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide at low cost a thick polycarbonate resin laminate useful for windows, water tanks and the like of vehicles, ships and aircrafts which are transparent and have good see-through properties. .

The present inventor has made earnest studies as a manufacture of a thick polycarbonate resin laminated plate which is transparent and has a good transparency with an adhesive. As a result, the polycarbonate resin sheet is bonded with a transparent adhesive which cures at a specific wavelength. Then, it has been found that the above object can be achieved. In addition, in bonding with a transparent adhesive that cures at this specific wavelength, if the water content of the polycarbonate resin sheet is set to a specific value or less in advance, the resulting polycarbonate resin laminated plate is heated to 160 ° C. or higher. However, it has been found that a bubble-free adhesive layer does not occur and a thick polycarbonate resin laminate capable of being heat-bent can be easily and inexpensively obtained, and the present invention has been completed.

[0007]

Means for Solving the Problems The present invention is characterized in that two or more polycarbonate resin sheets are laminated with a photo-curing adhesive which is hardened by near ultraviolet rays or visible rays having a wavelength of 320 to 800 nm. The present invention relates to a polycarbonate resin laminate having a thickness of 5 to 30 mm and a method for manufacturing the same.

The polycarbonate resin referred to in the present invention is an aromatic polycarbonate resin obtained by reacting a dihydric phenol and a carbonate precursor by a solution method or a melting method, and may be a mixture of two or more kinds of polycarbonate resins. . Its molecular weight is 1900 in terms of viscosity average molecular weight.
About 0 to 35,000 is preferable. The dihydric phenol used here is mainly 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), but part or all of it may be replaced with another dihydric phenol. . Other dihydric phenols include, for example, bis (4-hydroxyphenyl) methane, 1,1-bis (4
-Hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfide , Bis (4-hydroxyphenyl) sulfone and the like. Examples of the carbonate precursor include carbonyl halide, carbonyl ester, haloformate and the like, and specific examples thereof include phosgene, diphenyl carbonate and dihaloformate of dihydric phenol. Further, in producing the polycarbonate resin, a molecular weight modifier, a catalyst, a branching agent for improving processability and the like can be used if necessary. Further, in the polycarbonate resin, additives having various functions within a range not impairing the object of the present invention, for example, a releasing agent, a heat stabilizer such as a phosphorous acid ester, a phosphoric acid ester, a phosphonic acid ester, a benzotriazole type, an acetophenone type , A salicylic acid ester-based ultraviolet absorber, an antistatic agent, a colorant, a whitening agent, a flame retardant and the like may be blended. To add these additives, for example, a method of kneading during melt extrusion, a method of impregnating the surface,
An arbitrary method such as a coating method or a laminating method is adopted. In the present invention, as described below, the wavelength of the adhesive is 3
Since a photo-curing adhesive that cures with near-ultraviolet rays or visible rays of 20 to 800 nm, preferably 400 to 800 nm is used, even if an ultraviolet absorber is added to improve the weather resistance of the polycarbonate resin sheet, the photocuring reaction does not occur. Do not disturb The amount of such an ultraviolet absorber added is usually 0.01 to 0.5% by weight of the polycarbonate resin.

The polycarbonate resin sheet used in the present invention may be a sheet formed by any method, but is usually produced by a melt extrusion method. Specifically, a polycarbonate resin melted by an extruder is extruded into a sheet form from a T-type die, cooled by a plurality of cooling rolls, and then transferred by a plurality of transfer rolls and drawn. Cooling rolls are usually 2
Four rolls are used and 5 to 20 transfer rolls are usually used. The thickness of the polycarbonate resin sheet is not particularly limited, but is usually about 0.5 to 10 mm, preferably 1 to 5 mm
3 to 5 mm, which is relatively easy to obtain a sheet with good transparency, which is relatively unlikely to be affected by vibration of manufacturing equipment and cooling spots.
The thing of a grade is especially preferable. Further, the polycarbonate resin sheet used in the present invention may be subjected to various processing treatments for adding a new function. Examples of various processing treatments include various laminating treatments for improving the weather resistance of the polycarbonate resin, scratch resistance improving treatments for improving the surface hardness, surface graining, and semi-opaque treatments.

The adhesive used in the present invention is an adhesive which cures by a so-called light, that is, an electromagnetic wave, and cures, and has a wavelength of 320 to 800 nm, preferably 400 to 8 nm.
It initiates cross-linking and curing by near-ultraviolet or visible light having a wavelength of 00 nm and maintains transparency after cross-linking and curing. Such an adhesive is a composition comprising a radically polymerizable reactive polymer or oligomer, a monomer, a photopolymerization initiator, a thermal polymerization inhibitor, etc.
It is an epoxy-based, urethane-based or unsaturated polyester-based composition using a compound of near-ultraviolet or visible light decomposition type as a polymerization initiator. A more preferable example is a urethane composition containing a urethane acrylate component.

In order to maintain the transparency and transparency of the laminated plate,
The ratio (A / B) of the refractive index A after curing of the photocurable adhesive and the refractive index B of the polycarbonate resin sheet is 0.9 to 1.1.
Is more preferable, and it is more preferable that it is 0.95 to 1.05. If the difference between the refractive index A of the photocurable adhesive after curing and the refractive index B of the polycarbonate resin sheet becomes too large (A / B is less than 0.9 or exceeds 1.1), a photocurable adhesive layer is formed. At the interface of the polycarbonate resin sheet, the light transmittance is reduced due to irregular reflection, and the image distortion due to refraction is increased, resulting in poor transparency.

The light irradiation device used for curing the near-ultraviolet or visible light curing type adhesive is a high pressure mercury lamp, a metal halide type high pressure mercury lamp or the like. Preferably wavelength 320
A metal halide type dedicated to visible light is used in which light emission below nm is blocked by a filter or the like.

As a concrete method for producing the laminated sheet of the present invention, for example, a polycarbonate resin sheet is held horizontally, a predetermined amount of an adhesive is applied on the polycarbonate resin sheet, and the polycarbonate resin sheet is not trapped on the polycarbonate resin sheet. After stacking while pressing with a roll or the like, it is cured by irradiating near-ultraviolet or visible light with a predetermined light source having an emission wavelength for a predetermined time. If necessary, a sheet is further laminated on this laminated plate and adhesively laminated. In the case of stacking three or more sheets, it is also possible to irradiate light at the end and to cure and bond them collectively after providing a plurality of adhesive layers. Furthermore, the laminated plate of the present invention may be used in combination with inorganic glass or other transparent resin sheet, if necessary. The thickness of the laminate is in the range of 5 to 30 mm, preferably 10
The range is up to 20 mm.

When the polycarbonate resin sheets are laminated, the water content of the polycarbonate resin sheet is set to 100%.
It is preferable that the content is adjusted to ppm or less and used for lamination. Laminates obtained by laminating polycarbonate resin sheets with a high water content have little transparent distortion and are useful as applications such as relatively flat building windows and side windows of vehicles, but plates with curved surfaces on the other hand. Thermal bending is indispensable for processing, and bubbles are generated in the adhesive layer during heating, resulting in loss of transparency, making it difficult to obtain beautiful products. The laminated plate obtained by using such a polycarbonate sheet having a high water content cannot suppress the generation of bubbles in the adhesive layer even if it is sufficiently dried by preheating and subjected to heat bending. However, the laminated sheet obtained by laminating polycarbonate resin sheets having a water content of 100 ppm or less using the above adhesive does not generate bubbles in the adhesive layer when heated even when subjected to thermal bending at 160 ° C or more. A beautiful product can be obtained.

The water content of the polycarbonate resin sheet is 1
Any method may be used to reduce the amount to less than 00 ppm.
For example, using a hot air circulation type dryer at 100 to 120 ° C., 6
It may be heated and dried for 10 hours. Usually, a polycarbonate resin absorbs moisture quickly, and therefore it is preferable to immediately use a dried sheet for lamination. Thus, the water content is 10
The polycarbonate resin laminate of the present invention obtained by using a polycarbonate resin sheet of 0 ppm or less is 160 to 19
It can be softened by heating to 0 ° C. and subjected to heat bending such as commonly used vacuum forming, pressure forming, and press forming. When the laminated plate of the present invention is bent, it is preferable to pre-dry at 100 to 120 ° C. for 6 to 10 hours. By pre-drying, it is possible to obtain a better product without bubbles in the polycarbonate resin layer.

[0016]

EXAMPLES The present invention will be further described with reference to the following examples. The measurement items in the examples were as follows. (1) Perspective distortion: In accordance with the test method specified in JIS R 3211 (Test method for safety glass for automobiles), test area A
The test piece is tilted until the maximum value of the perspective distortion applied to 2 is 2 minutes, and the tilt angle at that time is shown. The smaller this angle, the better the transparency. (2) Water content: measured by the Karl Fischer method. (3) Adhesive strength: Measured according to JIS K 6852 (compression shear adhesive strength test method for adhesives). (4) Refractive index: Measured at a temperature of 25 ° C. by an Appe refractometer using a sodium lamp as a light source in accordance with JIS K 0062 (method for measuring refractive index of chemicals).

[Example 1] Thickness 5 mm, width 200 mm, length 300 mm, perspective distortion 40 produced by melt extrusion method
° Polycarbonate resin sheet with a water content of 1200 ppm and a refractive index of 1.59 [Panlite sheet manufactured by Teijin Chemicals Ltd.
PC-1111] has a main reaction wavelength of 420 nm on one side,
Apply 6 g of visible light curable adhesive [Adel BENEFIX PC] (refractive index 1.63 after photo-curing) and push the same polycarbonate resin sheet to one side to prevent bubbles from entering the adhesive. After laminating in this manner, a hydraulic press was used to remove excess adhesive so that the thickness of the adhesive was 20 μm, to obtain a laminated plate. This laminated plate was set to 4000 by a photocuring device equipped with a metal halide lamp for visible light [Σ line manufactured by Morita Tokyo Mfg. Co., Ltd.].
The laminated plate having a thickness of about 10 mm was obtained by irradiating with energy of mj / cm ² . This laminate has a perspective distortion of 30 ° and an adhesive strength of 85.
kg. Polycarbonate resin plate with a thickness of 10 mm obtained by the melt extrusion method [Teijin Kasei Co., Ltd. Panlite Sheet
Compared to the perspective distortion of 85 ° of PC 1111], the distortion of the background image seen through is extremely small, and it is extremely useful as a side window for buildings and vehicles.

This laminated plate was heated in a hot air circulating drying oven to 12
It was pre-dried at 0 ° C. for 6 hours, heated at 180 ° C. for 20 minutes to be softened, and press-bent using a mold having a radius of 60 mm. The generation of countless fine bubbles was observed in the adhesive layer of the obtained processed product.

Example 2 Two 5 mm thick polycarbonate resin sheets similar to those used in Example 1 were dried at 120 ° C. for 8 hours by a hot air circulation dryer to obtain a water content of 80 ppm.
I made it. Two polycarbonate resin sheets were laminated in the same manner as in Example 1 to obtain a laminated plate. The perspective distortion of this laminate was 30 ° and the adhesive strength was 85 kg.

This laminated plate was heated in a hot air circulation drying furnace to 12
It was pre-dried at 0 ° C. for 6 hours, heated at 180 ° C. for 20 minutes to be softened, and press-bent using a mold having a radius of 60 mm. No bubbles were observed in the adhesive layer or the polycarbonate resin layer of the obtained product.

[Example 3] Four polycarbonate resin sheets having the same thickness of 5 mm as used in Example 1 were dried at 120 ° C for 8 hours by a hot air circulation dryer to obtain a water content of 80 ppm.
I made it. Four sheets of this polycarbonate resin sheet were sequentially laminated via an adhesive layer to obtain a laminated plate having a thickness of about 20 mm and a 7-layer structure having 3 layers of an adhesive layer having a thickness of 10 μm. This laminated plate was irradiated with energy of 8000 mj / cm ² using the same apparatus as in Example 1 to obtain a laminated plate. The perspective distortion of this laminate was 55 ° and the adhesive strength was 85 kg. When this laminate was subjected to 12 thermal cycle tests from + 80 ° C to -30 ° C, no change was observed. Similar thickness 5
As compared with the perspective distortion of 90 ° or more of the polycarbonate resin plate having a thickness of 20 mm obtained by laminating four polycarbonate resin sheets having a thickness of 4 mm by hot pressing, there was almost no distortion of the background transparent image.

This laminated plate was heated in a hot air circulation drying furnace to 12
It was pre-dried at 0 ° C. for 6 hours, heated at 180 ° C. for 20 minutes to be softened, and press-bent using a mold having a radius of 60 mm. No bubbles were observed in the adhesive layer or the polycarbonate resin layer of the obtained product.

Example 4 Three 5 mm thick polycarbonate resin sheets similar to those used in Example 1 were dried at 120 ° C. for 8 hours by a hot air circulation dryer to obtain a water content of 80 ppm.
I made it. Three sheets of this polycarbonate resin sheet were sequentially laminated with an adhesive layer interposed therebetween to obtain a laminated plate having a five-layer structure having a thickness of about 15 mm and having two adhesive layers having a thickness of 10 μm. This laminate had a perspective distortion of 50 ° and an adhesive strength of 85 kg.

This laminated plate was heated in a hot air circulating drying oven to 12
It was pre-dried at 0 ° C. for 6 hours, then heated at 180 ° C. for 15 minutes to be softened, and press-bent using a mold having a radius of 800 mm. No bubbles were observed in the adhesive layer or the polycarbonate resin layer of the obtained product.

[Comparative Example 1] An ultraviolet curable adhesive [3054 made by ThreeBond Co., Ltd.] which is cured by ultraviolet rays having a wavelength of 200 to 400 nm and a light irradiation device [UV 1801 made by Mitsubishi Rayon Engineering Co., Ltd.] having a high pressure mercury lamp were used. Using the same procedure as in Example 1, a laminate having a three-layer structure and a thickness of about 10 mm was prepared. The irradiation energy amount at this time is 3200
It was 0 mj / cm ² . The obtained laminated plate was already colored yellow so that it could be visually confirmed. Furthermore, the adhesive strength of this laminate was as low as 12.5 kg / cm ^2, and it was confirmed that the adhesive was not sufficiently cured. When this laminated plate was heated up to 80 ° C., countless minute bubbles were generated in the adhesive layer, which was of no commercial value.

[0026]

EFFECTS OF THE INVENTION According to the present invention, a thick polycarbonate resin laminated plate, which is transparent and has a good see-through property, and which can be heat-bent, is useful for windows, water tanks, etc. of vehicles, ships, aircrafts, etc. at low cost. The industrial effects that can be achieved are exceptional.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29K 69:00 B29L 9:00

Claims (4)

[Claims] 1. A polycarbonate resin laminate having a thickness of 5 to 30 mm, characterized in that two or more polycarbonate resin sheets are bonded together with a photo-curing adhesive which is hardened by near-ultraviolet rays or visible rays having a wavelength of 320 to 800 nm. . 2. The polycarbonate resin laminate according to claim 1, wherein the polycarbonate resin sheet to be used for lamination has a water content of 100 ppm or less. 3. The ratio (A / B) of the refractive index A of the photocurable adhesive after photocuring to the refractive index B of the polycarbonate resin sheet.
Is 0.9-1.1, The polycarbonate resin laminated board of Claim 1 characterized by the above-mentioned. 4. A method for producing a laminated board in which two or more polycarbonate resin sheets are bonded together with a photo-curing adhesive that is hardened by near-ultraviolet rays or visible rays having a wavelength of 320 to 800 nm. Of water content of 100ppm or less
A method for manufacturing a 30 mm polycarbonate resin laminate.