KR20200089801A - Polycarbonate sheet with excellent chemical resistance and weather resistance - Google Patents

Abstract

The present invention relates to a polycarbonate sheet comprising a UV blocking agent, and more particularly, comprises a polycarbonate layer that is stable to UV and a coating layer containing a UV blocking agent, characterized in that it is produced by a coextrusion process, and chemical resistant. It relates to a polycarbonate sheet characterized by excellent chemical resistance and weather resistance. A polycarbonate layer comprising at least one selected from the group consisting of polycarbonate stabilizers, UV stabilizers and flame retardants and polycarbonate; A polycarbonate sheet comprising a coating layer comprising at least one selected from the group consisting of polycarbonate, copolymerized polycarbonate, UV blocking agent and antioxidant, and wherein the coating layer is laminated on at least one surface of the polycarbonate layer. Is provided. According to the present invention, by including a polycarbonate or copolymerized polycarbonate resin in the coating layer of the polycarbonate layer, it provides the effect of improving the transparency and weatherability by ensuring the compatibility of the polycarbonate layer and the coating layer. Therefore, since the physical stability of the polycarbonate sheet is maintained by blocking the UV, there is an effect capable of securing stability during processing.

Description

Polycarbonate sheet with excellent chemical resistance and weather resistance}

The present invention relates to a polycarbonate sheet comprising a UV blocking agent, and more particularly, comprises a polycarbonate layer that is stable to UV and a coating layer containing a UV blocking agent, characterized in that it is produced by a coextrusion process, and chemical resistant. It relates to a polycarbonate sheet characterized by excellent chemical resistance and weather resistance.

Polycarbonate is a thermoplastic resin produced by reacting bisphenol A with phosgene, and is transparent because it is non-crystalline. It is excellent in heat resistance, strength, and dimensional stability, especially impact strength, and is used in various fields such as industry, construction, and medical. In addition, it is an engineering plastic that has various properties that have very little dimensional change due to moisture absorption and stable physical properties according to temperature changes.

On the other hand, the plastic sheet containing the polycarbonate can be used for a long time and has the advantage of weight reduction, but it is vulnerable to ultraviolet rays (UV) and has low chemical resistance, so even if a UV stabilizer or a UV blocker is added, UV and acid rain when exposed to the outdoors for a long time There is a lot of inconvenience to use for a particularly transparent use because the surface is blurred by a back. In addition, since UV stabilizers and blockers are expensive, there is a disadvantage that it is not economical because it is difficult to input large amounts.

Korean Patent Publication No. 10-2009-0105597 relates to a sheet having excellent weatherability used for transparent soundproof walls, skylights, roofs, canopies, or connecting passages of buildings, etc. It relates to a sheet for a soundproof wall having excellent weather resistance that can be blocked and also maintain the impact strength.

Korean Registered Patent Publication No. 10-1347776 discloses a coating solution, a soundproof wall using the same, and a method for manufacturing the same. In particular, while containing a UV stabilizer and a UV blocking agent, the weight ratio of the UV stabilizer to the UV blocking agent is 3:4, a coating solution and a film, a coating layer formed on one side of the film, and a glass formed on the other side of the film. Including, the coating layer is a sound barrier characterized in that it contains a UV stabilizer and a UV blocking agent in a ratio of 3:4.

Korean Registered Patent Publication No. 10-1451930 is a patterned soundproof panel in which the first and second adhesive layers having UV blocking and heat resistance are integrally formed to be located on the front and rear surfaces of the printed layer, and the printed layer and the first and second adhesive layers are formed. A transparent resin layer is formed between UV protection and the soundproof panel by UV curing resin to protect the printed layer by the first and second adhesive layers and the transparent resin layer, thereby preventing discoloration and fading of the printed layer, thereby preventing the life of the soundproof panel. Disclosed is a soundproof panel having a UV blocking function capable of increasing extension and durability, a manufacturing method thereof, and a soundproof wall using the same.

As described above, there are various known techniques for sheets having improved weather resistance including resins such as polycarbonate. Accordingly, the present invention is completed on the polycarbonate sheet including the polycarbonate layer and the coating layer, in particular, by adjusting the resin and composition of the coating layer, focusing on improving chemical resistance and weatherability and also improving economic efficiency in the manufacturing process. Did.

Korean Patent Publication No. 10-2009-0105597 (2009.10.07) Korean Patent Registration Publication No. 10-1347776 (2014.01.27) Korean Patent Registration Publication No. 10-1451930 (2014.10.22)

The present invention aims to solve all of the above-mentioned problems.

An object of the present invention is to include a polycarbonate or copolymer polycarbonate resin in the coating layer of the polycarbonate layer, to improve the transparency and weather resistance by ensuring the compatibility of the polycarbonate layer and the coating layer.

Another object of the present invention is to provide a polycarbonate sheet that further improves economic efficiency, chemical resistance, and weatherability by reusing a coating layer containing an expensive UV blocking agent in a carbonate layer in a sheet manufacturing process.

In order to achieve the object of the present invention as described above and to realize the characteristic effects of the present invention described later, the characteristic configuration of the present invention is as follows.

A polycarbonate layer comprising at least one selected from the group consisting of polycarbonate stabilizers, UV stabilizers and flame retardants according to the present invention and polycarbonate; A polycarbonate sheet comprising a coating layer comprising at least one selected from the group consisting of polycarbonate, copolymerized polycarbonate, UV blocking agent and antioxidant, and wherein the coating layer is laminated on at least one surface of the polycarbonate layer. Is provided.

In one preferred example of the present invention, the polycarbonate layer may include 0.1 to 1 part by weight of a polycarbonate stabilizer, 0.1 to 5 parts by weight of a UV stabilizer, and 0.1 to 3 parts by weight of a flame retardant with respect to 60 to 95 parts by weight of polycarbonate. have.

In one preferred example of the present invention, the copolymerized polycarbonate included in the coating layer is a copolymer comprising at least one of a polycarbonate-polyester copolymer, an organopolysiloxane-polycarbonate and an alkylene-ester polymer. It is characterized by.

In one preferred embodiment of the present invention, the polycarbonate-polyester copolymer comprises isophthalate-terephthalate-resorcinol ester, and the polymer alkylene-ester polymer is ethylene terephthalate-1,4-cyclo Hexanedimethylene terephthalate.

The weight average molecular weight (Mw) of the polycarbonate or the copolymerized polycarbonate is 10,000 to 100,000 is provided, preferably 20,000 to 50,000.

In one preferred example of the present invention, the UV blocking agent may contain 0.01 to 5 parts by weight based on 60 to 95 parts by weight of the polycarbonate or copolymerized polycarbonate in the coating layer. Preferably 1 part by weight may be provided.

In one preferred embodiment of the present invention, the UV blocking agent is at least selected from benzotriazole-based, hindered-amine-based, benzophenone-based, salicylate-based, benzylidene malonate-based, triazine-based, cinnamic acid derivatives and oxanilide It may include one, the antioxidant may include at least one selected from phenol-based and phosphorus-based.

In one preferred example of the present invention, the coating layer may have a thickness of 0.01 to 0.5 mm.

In one preferred example of the present invention, the laminated coating layer may be at least one layer.

In one preferred example of the present invention, the thickness of the sheet may be 1 to 10 mm.

In one preferred example of the present invention, the UV wavelength blocked by the sheet may be 280 to 350 nm.

On the other hand, the polycarbonate sheet may be characterized in that it is produced by at least one or more processes selected from the group consisting of coextrusion, coextrusion lamination, coextrusion molding, sheet molding and multiple injection molding.

Particularly, in the case of the process by the coextrusion lamination, the residual coating layer not included in the extrudate is characterized in that it is reused in the polycarbonate layer forming step.

In the case of the process by the coextrusion lamination, the lamination is at least one layer, and the thickness ratio of the polycarbonate layer and the coating layer is 1: 0.001 to 1, characterized in that the polycarbonate sheet is provided.

As described above, according to the present invention, by including a polycarbonate or copolymerized polycarbonate resin in the coating layer of the polycarbonate layer, it provides the effect of improving the transparency and weatherability by ensuring the compatibility of the polycarbonate layer and the coating layer.

Therefore, since the physical stability of the polycarbonate sheet is maintained by blocking the UV, there is an effect capable of securing stability during processing.

According to the present invention, it provides an effect of improving economic efficiency by reusing the coating layer containing the UV blocking agent, which is expensive in the manufacturing process, to the carbonate layer.

Due to these effects, it provides an effect of improving weather resistance by improving chemical resistance and preventing yellowing and the like compared to a conventional sheet.

1 is a polycarbonate sheet according to the present invention shows the results of observing the difference in yellowing degree (ΔYI, △Yellow Index), which is a discoloration degree when accelerated weathering test for 500 to 2,000 hours according to KS M ISO 4892-3. .
Figure 2 shows the change in haze (ΔHaze) when the polycarbonate sheet according to the present invention was subjected to accelerated weathering test for 500 to 2,000 hours according to KS M ISO 4892-3.
Figure 3 shows the results of measuring the yellowness (b*) when the primary, secondary and tertiary reuse of the coating layer on the polycarbonate sheet according to the present invention.

For a detailed description of the present invention, which will be described later, reference is made to the accompanying drawings that illustrate, by way of example, specific embodiments in which the invention may be practiced. These examples are described in detail enough to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the invention are different, but need not be mutually exclusive. For example, the specific shapes, structures, and properties described herein can be implemented in other embodiments without departing from the spirit and scope of the invention in relation to one embodiment. In addition, it should be understood that the location or placement of individual components within each disclosed embodiment can be changed without departing from the spirit and scope of the invention. Therefore, the following detailed description is not intended to be taken in a limiting sense, and the scope of the present invention, if appropriately described, is limited only by the appended claims, along with all ranges equivalent to those claimed. In the drawings, similar reference numerals refer to the same or similar functions across various aspects.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those skilled in the art to easily implement the present invention.

The polycarbonate sheet according to the present invention comprises a polycarbonate layer comprising at least one or more selected from the group consisting of polycarbonate stabilizer, UV stabilizer and flame retardant and polycarbonate; It is composed of a coating layer comprising at least one selected from the group consisting of polycarbonate, copolymerized polycarbonate, UV blocking agent and antioxidant, characterized in that the coating layer is laminated on at least one surface of the polycarbonate layer. In this case, the coating layer is laminated on at least one surface of the polycarbonate layer, and it is possible to laminate on a single surface or both surfaces of the polycarbonate layer.

In one preferred example of the present invention, polycarbonate is a type of thermoplastic. It has characteristics such as impact resistance, heat resistance, weather resistance, self-extinguishing property, and transparency, and has an impact degree of about 150 times or more that of tempered glass, so it has excellent flexibility and processability. It is a substitute for acrylic that is easily broken and easily deformed, and is often used as a supplement to ordinary plate glass. The UV absorption wavelength of the polycarbonate according to the present invention is 260 nm or less. Also, the most sensitive absorption wavelength is about 295 nm. Therefore, yellowing may be prevented by blocking ultraviolet rays in the absorption wavelength range.

In addition, typically, the polycarbonate resin may have a form of a linear polycarbonate resin, a branched polycarbonate resin, a polyester carbonate copolymer resin, etc., as the polycarbonate resin included in the polycarbonate resin composition used in the present invention It is not limited to a specific form, and these linear polycarbonate resins, branched polycarbonate resins, polyester carbonate copolymer resins, and the like can all be used.

In one preferred example of the present invention, the polycarbonate layer comprises 60 to 95 parts by weight of polycarbonate, 0.1 to 1 part by weight of a polycarbonate stabilizer, 0.1 to 5 parts by weight of a UV stabilizer and 0.1 to 3 parts by weight of a flame retardant It is characterized by.

The polycarbonate stabilizer may be provided with an antioxidant containing phosphorus, which can prevent thermal oxidation decomposition and unwanted yellowing of the polymer during melt processing. As an example of a stabilizer, a commercially available and obtainable trade name Hostanox P-EPQ may be provided, but is not limited thereto. When extruding and injection molding, or when recycling polycarbonate, plastics tend to discolor. Hostanox P-EPQ can prevent plastics from discoloring. It can be seen that it contributes to stabilizing polycarbonate during extrusion molding, preventing discoloration, stabilizing polycarbonate when recycling polycarbonate, and stabilizing polycarbonate under extreme conditions.

In one preferred example of the present invention, the polycarbonate stabilizer may contain 0.1 to 1 part by weight, preferably 0.1 to 0.7 part by weight, and more preferably 0.1 to 0.5 part by weight based on 60 to 95 parts by weight of the polycarbonate. Can. When the polycarbonate stabilizer is contained in an amount of less than 0.1 parts by weight, it is difficult to stabilize the polycarbonate, the color change may not be properly prevented, and when it is included in excess of 1 part by weight, the harmony with other properties is inferior. The above range is provided because a preferred sheet cannot be produced.

In one preferred example of the present invention, the UV stabilizer may contain 0.1 to 5 parts by weight, preferably 0.1 to 4 parts by weight, and more preferably 0.1 to 3 parts by weight based on 60 to 95 parts by weight of the polycarbonate. have. When the UV stabilizer is included in less than 0.1 parts by weight, the radical may not be processed and UV blocking may not be properly performed, and when it is included in excess of 5 parts by weight, the balance with other physical properties is poor, so the preferred sheet according to the present invention Cannot be manufactured.

The UV stabilizer according to the present invention may include at least one selected from benzotriazole-based and hindered amine light stabilizers (HALS). Particularly, the HALS is a representative material of radical scavengers that catch radicals, and is used to supplement polymer radicals, etc., which are formed by preventing 100% UV blocking despite the use of UV blocking agents. It is mainly effective in preventing gloss loss, yellowing, cracking and chalking. Most resins have a synergistic effect by using a UV blocker and a UV stabilizer at the same time.

In one preferred example of the present invention, the flame retardant contains 0.1 to 3 parts by weight based on 60 to 95 parts by weight of the polycarbonate, and serves to improve the flame resistance of polycarbonate and other additives. Halogen-based flame retardants can be provided. Decabromodiphenyl oxide (DBDPO), Decabromodiphenyl ethane (DBDPE), Hexabromocyclododecane (HBCD), Tetrabromobisphenol-A (TBBA, Tetrabromobisphenol-A) ), tetrabromobisphenol A bis 2,3-dibromopropyl ether (BDDP), and the like may be provided, but is not limited thereto.

In one preferred example of the present invention, the copolymerized polycarbonate contained in the coating layer is characterized in that it is a copolymer comprising at least one or more of a polycarbonate-polyester copolymer and an organopolysiloxane-polycarbonate. In particular, in the case of a polysiloxane-polycarbonate copolymer, transparency may be provided.

In this case, since the polycarbonate and the copolymerized polycarbonate included in the coating layer are compatible with the polycarbonate of the polycarbonate layer, transparency of the sheet can be maintained. That is, both the polycarbonate layer and the coating layer are based on an amorphous polycarbonate, and do not affect transparency. Therefore, while maintaining transparency, the yellowing phenomenon may be prevented by the coating layer including the UV blocking agent, and chemical resistance may also be improved.

In addition, it is possible to provide a sheet that can also improve economic efficiency by recycling a coating layer containing an expensive UV blocking agent to a polycarbonate layer in a coextrusion process to enable commercial use.

In particular, the copolymerized polycarbonate included in the coating layer may include at least one or more of a copolymer of polycarbonate-polyester, organopolysiloxane-polycarbonate and alkylene-ester polymer.

In one preferred embodiment of the present invention, the polycarbonate-polyester copolymer comprises isophthalate-terephthalate-resorcinol ester, and the polymer alkylene-ester polymer is ethylene terephthalate-1,4-cyclo Hexanedimethylene terephthalate. Preferably, in this case, transparency can be maintained when the isophthalate-terephthalate-resorcinol ester and the weight part of the 1,4-cyclohexanedimethylene terephthalate include 40% or more of the total resin composition. . In addition, as the content of isophthalate-terephthalate-resorcinol ester increases, transparency can be increased, so that it can be adjusted as needed during manufacture.

Including the copolymer, it has excellent gloss, gloss retention and color stability, and it is possible to omit UV coating or paint processes. It is possible to maintain the original color better than the existing polycarbonate, and maintain excellent transparency. In addition, the existing color and physical properties can be maintained.

In one preferred example of the present invention, the weight average molecular weight (Mw) of the polycarbonate or copolymerized polycarbonate is characterized by being 10,000 to 100,000, and preferably 20,000 to 70,000 may be provided.

In one preferred example of the present invention, the UV blocking agent is contained in an amount of 0.01 to 5 parts by weight based on 60 to 95 parts by weight of polycarbonate or copolymerized polycarbonate in the coating layer. Preferably 0.1 to 4 parts by weight, more preferably 1 part by weight may be included. When the UV blocking agent is contained in an amount of less than 0.1 parts by weight, UV blocking may not be properly performed, and when it is included in an amount exceeding 5 parts by weight, the harmony with other physical properties is poor, so a preferred sheet according to the present invention cannot be produced. .

In one preferred embodiment of the present invention, the UV blocking agent is at least selected from benzotriazole-based, hindered-amine-based, benzophenone-based, salicylate-based, benzylidene malonate-based, triazine-based, cinnamic acid derivatives and oxanilide It can contain one.

The UV blocker uses the principle of converting a molecule that has been excited by light energy into a ground state by keto-enol tautomerization (proton delocalization) instead of thermal energy.

As the benzotriazole type, commercially obtainable trade names such as TINUVIN 234, TINUVIN 234, TINUVIN 326, TINUVIN 329, TINUVIN 360 (Shiba Gage, Cibageigy), etc. or trade names SONGSORB 2340, SONGSORB 3200 (Songwon Industrial Co., Ltd.), etc. may be provided. , Most preferably, TINUVIN 326 may be provided, and the structural formula thereof is as follows.

[Structural Formula 1]

The benzotriazole-based keto-enol tautomerization is provided as follows.

[Benzotriazole-based keto-enol tautomerization]

Hindered amine light stabilizers (HALS) are compounds containing amine functional groups used as stabilizers in plastics and polymers. These compounds are typically derivatives of tetra methyl piperidine and are mainly used to protect polymers from photooxidation effects. In contrast to other types of polymer degradation, such as ozone degradation. It is widely used as a heat stabilizer. The structural formula is provided as follows.

[Structural Formula 2]

Benzophenone series can be used as photoinitiators in UV curing applications such as ink, imaging and clear coating in the printing industry. Benzophenone prevents UV (UV) light from damaging fragrance and color in products such as perfumes and soaps. In addition, it can be added to the plastic packaging material as a UV blocker to prevent photolysis of the packaging polymer or its contents. It can be used to package the product in transparent glass or plastic (eg PETE water bottles). Without benzophenone, opaque or dark packaging is required. The structural formula is provided as follows.

[Structural Formula 3]

In addition, benzophenone-based keto-enol tautomerization is provided as follows.

[Benzophenone-based keto-enol tautomerization]

The benzylidene malonate system can be provided with the commercially available trade name Hostavin B-CAP. The structural formula is provided as follows. Hostavin B-CAP is a highly efficient UV blocker in the field of engineering plastics. It is possible to maintain the initial color of the polycarbonate resin at its best. Hostavin B-CAP can be applied to polyesters, polycarbonates and polymethyl methacrylates, and when used together with amine-based light stabilizers, it can significantly improve the anti-degradation performance. It has the following structural formula.

[Structural Formula 4]

The triazine system has the following structural formula. 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine are shown in order.

[Structural Formula 5]

Triazine-based keto-enol tautomerization is provided as follows.

[Triazine-based keto-enol tautomerization]

Namsan (C ₆ H ₅ CH=CHCOOH) has cis-type and trans-type, but usually refers to trans-type. It is present in nature, but is easily synthesized from benzaldehyde. Colorless needle-like crystal with weak aroma, molecular weight 148.16, melting point 135℃. It has a boiling point of 300°C and a specific gravity of 1.25. Soluble in ethanol and ether. It is present in the form of glass or ester, such as broiler oil (cassia oil), peruvian balsam, and fragrant oil. Since esters are aromatic, they are used in fragrances and cosmetics. Cinnamic acid derivatives refer to the derivatives of cinnamic acid, and include cyanoacrylate and malonates.

Oxanilide is a scaly crystal (recrystallized from benzene or nitrobenzene) and has a melting point of 254°C (252 to 253°C) and a boiling point of 360°C or higher. Easily soluble in benzene, but insoluble in hot ethanol and insoluble in water and ether. Keto-enol tautomerization of oxanilide is provided as follows.

[Oxanilide keto-enol tautomerization]

In addition, it is possible to provide a UV blocking agent such as salicylate, which is well known to those skilled in the art, and is not limited thereto. As a result, the present invention can provide a sheet having a further improved weather resistance by including a UV-blocking agent on the polycarbonate layer, a polycarbonate or a copolymerized polycarbonate as a base, and a UV blocking agent.

In one preferred example of the present invention, the copolymerized polycarbonate contained in the coating layer may further include a functional reinforcing material, a flame retardant, an antioxidant, and the like in addition to a copolymer of polycarbonate and polyester. Therefore, the timing or method of addition is not particularly limited. Direct mixing or kneading or adding to a high concentration masterbatch may be provided, but is not limited thereto.

The functional reinforcing material may include at least one selected from impact resistance, antistatic agents, mold release agents, plasticizers, colorants, and nucleating agents.

The impact resistance agent can reinforce the low-temperature impact strength of the plastic by blending a rubber/elastomer having a low glass transition temperature (Tg).

The antioxidant may include at least one selected from phenol, lactone, phosphite, and thioester.

In general, resin is used as a synthetic resin or final product, and when it is continuously exposed to high temperature, thermal oxidation occurs and yellowing is a phenomenon that is derived. Types of antioxidants include primary antioxidants and secondary antioxidants. As the primary antioxidant, hindered phenol (hindered phenol), lactone (lactone) system is used, and as the secondary antioxidant, phosphorus (phosphite), thioester (thioester) system is used. The role of the primary antioxidant is a radical scavenger, and the hindered phenol system handles oxygen centered radicals. Secondary antioxidants act as hydroperoxide (ROOH) decomposer. Since antioxidants increase synergistic effects by using both primary and secondary antioxidants in most resins, hindered phenol, lactone, and phosphite systems are mixed in an appropriate ratio. Has been used. 2,6-di-t-Butyl-4-methylphenol, 2,2-Me thylenebis(4-methyl-6-t-butylphenol) may be provided as the phenolic, and Bis(2,4- di-t-butyl), Tris(2,4-di-t-butylphenyl)-phosphite, and the like can be provided.

In one preferred example of the present invention, the coating layer may be provided with a thickness of 0.01 to 0.5mm.

In one preferred example of the present invention, the laminated coating layer may be at least one layer.

In one preferred example of the present invention, the thickness of the sheet is 1 to 10 mm is provided, preferably 6 to 8 mm.

In one preferred example of the present invention, the UV wavelength blocked by the sheet may be 280 to 350 nm, preferably 300 to 340 nm, more preferably 310 to 330 nm, and most preferably 320 nm.

On the other hand, the above-described polycarbonate sheet is provided with a polycarbonate sheet characterized in that it is produced by at least one or more processes selected from the group consisting of coextrusion, coextrusion lamination, coextrusion molding, sheet molding and multiple injection molding. It is preferably provided that is formed by coextrusion or coextrusion lamination. Coextrusion may be used when producing extrusion coating, film or sheet using two or more extruders, and means a general method of making a multi-layered structure by adding one or more layers. The coextrusion according to the present invention is not particularly limited, and allows a polycarbonate layer and a coating layer to be formed by a general coextrusion process. In the coextrusion process, a method of bonding a polycarbonate layer and a coating layer extruded from two or more extruders in a roll may be provided, or a method of coextrusion with a single extrusion die using a multi-flow nozzle may be provided. It is not.

Coextrusion may be applied to the top or bottom surface of the polycarbonate layer, and may be formed by laminating coating layers on both the upper and lower surfaces.

In the case of the process by the coextrusion lamination, the residual coating layer not included in the extrudate is characterized in that it is reused in the polycarbonate layer forming step. Therefore, the resin composition of the coating layer containing the expensive UV blocking agent is not thrown away, and is reused in a commercially available polycarbonate layer, which is an economical advantage. Such recycling requires that the coating layer and the polycarbonate layer are compatible to maintain transparency. In addition, by including a UV blocking agent in the polycarbonate layer, it can also help to improve the prevention of yellowing caused by ultraviolet light, and may also help to improve weatherability.

In one preferred example of the present invention, the lamination in the coextrusion step is at least one layer, and a thickness ratio of the polycarbonate layer and the coating layer may be 1:0.001 to 1.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is provided as a preferred example of the present invention and cannot be interpreted as limiting the present invention in any sense.

The contents not described herein will be sufficiently technically inferred by those skilled in the art, and thus the description thereof will be omitted.

[Example]

Coextrusion sheets were prepared so that a polycarbonate layer and a coating layer including a UV blocking agent were formed on the upper and lower surfaces. Here, the polycarbonate layer contains 80 parts by weight of polycarbonate, 0.5 parts by weight of Hostanox P-EPQ, 3 parts by weight of HALS, 1 part by weight of DBDPO and 3 parts by weight of PET, and the coating layer is 80 parts by weight of copolymerized polycarbonate, Hostavin B A sheet was prepared including 0.5 part by weight of CAP, 0.1 part by weight of 2,6-di-t-Butyl-4-methylphenol, and 0.1 part by weight of Bis(2,4-di-t-butyl).

In addition, in the manufacturing process, the residual coating layer that was not included in the product in the extrusion process and was detached was manufactured by including the polycarbonate layer. On the other hand, since co-extrusion is a generally known extrusion method, detailed description thereof will be omitted.

[Comparative example]

The resin of the coating layer according to the example was prepared by using PS168 as a UV blocking agent without using a copolymerized polycarbonate. In addition, it was prepared in the same manner as in Example 1, except that the polycarbonate layer did not include a residual coating layer that was not included in the product in the extrusion process in the manufacturing process and fell off.

[Experimental Example 1]

The sheet produced according to the Examples and Comparative Examples shows the results of observing the yellowness difference (△YI, △Yellow Index), which is the color change, when the accelerated weathering test was performed for 500 to 2,000 hours according to KS M ISO 4892-3. . In the accelerated weathering test, a UVA-340 (type 1A) fluorescent UV lamp was used, and when exposed to UV, the radiation amount was 0.76 Wm-2Хnm-1, the exposure time was 8 hours, and the exposure temperature was 60±1°C. And the condensation time for blocking the UV lamp was 4 hours, and the temperature was 50±1°C. The yellowness was determined by the test method for yellowness of plastics according to KS M 3026. The results are shown in FIG. 1.

[Experimental Example 2]

Sheets prepared according to Examples and Comparative Examples exhibited a change in cloudiness (ΔHaze) when tested for accelerated weathering for 500 to 2,000 hours according to KS M ISO 4892-3. The blurring was defined as a method for measuring the blurring of plastic transparent materials according to KS M ISO 14782.

[Experimental Example 3]

In the sheets prepared according to Examples and Comparative Examples, Yellowness (b*) was measured by reusing (recycling) the remaining coating layer on the polycarbonate layer once, twice, and three times, respectively. The results are shown in FIG. 2.

Referring to FIG. 1, in the case of the embodiment according to the present invention, it was confirmed that the yellowness index of the polycarbonate layer is low, and thus the ability to withstand the external environment is excellent. Therefore, even when exposed to ultraviolet light for a long time, it is possible to block a wide range of ultraviolet rays. Accordingly, it can be inferred that it can be used in the long term because the yellowing value hardly increases as a result of observation through the yellowing difference value.

In addition, referring to FIG. 2, in the case of the embodiment according to the present invention, it was confirmed that the change in blurring (ΔHaze) and that the value was almost unchanged compared to the comparative example, and that transparency was also maintained.

Finally, referring to Figure 3, it can be seen that the sheet produced according to Experimental Example 3 of the present invention has a significantly lower Yellowness (b*) value than the comparative example. From this, it can be seen that by reusing the coating layer compatible with the polycarbonate layer, the UV blocking ability is improved, and the expensive UV blocking agent is recycled to the polycarbonate layer to be used as an excellent economical sheet.

In the above, the present invention has been described by specific embodiments, such as specific components, and limited embodiments and drawings, which are provided to help the overall understanding of the present invention, but the present invention is not limited to the above embodiments , Those skilled in the art to which the present invention pertains can make various modifications and variations from these descriptions.

Accordingly, the spirit of the present invention is not limited to the above-described embodiment, and should not be determined, and all claims that are equally or equivalently modified as well as the claims below will fall within the scope of the spirit of the present invention. Would say

Claims (15)

A polycarbonate layer comprising at least one selected from the group consisting of polycarbonate stabilizers, UV stabilizers and flame retardants and polycarbonate;
It consists of a coating layer comprising at least one selected from the group consisting of polycarbonate, copolymerized polycarbonate, UV blocking agent and antioxidant,
The polycarbonate sheet, characterized in that the coating layer is laminated on at least one side of the polycarbonate layer.
According to claim 1,
The polycarbonate layer is a polycarbonate sheet, characterized in that it comprises 0.1 to 1 part by weight of a polycarbonate stabilizer, 0.1 to 5 parts by weight of a UV stabilizer and 0.1 to 3 parts by weight of a flame retardant with respect to 60 to 95 parts by weight of polycarbonate.
According to claim 1,
The copolymer polycarbonate contained in the coating layer is a polycarbonate sheet, characterized in that it comprises at least one or more of a copolymer of polycarbonate-polyester, organopolysiloxane-polycarbonate and alkylene-ester polymer.
The method of claim 3,
The polycarbonate-polyester copolymer includes isophthalate-terephthalate-resorcinol ester, and the polymer alkylene-ester polymer comprises ethylene terephthalate-1,4-cyclohexanedimethylene terephthalate Polycarbonate sheet characterized by.
According to claim 1,
Polycarbonate sheet, characterized in that the weight average molecular weight (Mw) of the polycarbonate or copolymerized polycarbonate is 10,000 to 100,000.
According to claim 1,
Polycarbonate sheet, characterized in that it comprises from 0.01 to 5 parts by weight of UV blocking agent relative to 60 to 95 parts by weight of polycarbonate or copolymerized polycarbonate in the coating layer.
According to claim 1,
The UV blocking agent includes at least one selected from the group consisting of benzotriazole-based, hindered-amine-based, benzophenone-based, salicylate-based, benzylidene malonate-based, triazine-based, cinnamic acid derivatives, and oxanilide. Polycarbonate sheet characterized by.
According to claim 1,
The antioxidant is a polycarbonate sheet, characterized in that it comprises at least one selected from phenol-based and phosphorus-based.
According to claim 1,
The coating layer is a polycarbonate sheet, characterized in that the thickness is 0.01 to 0.5 mm.
According to claim 1,
The laminated coating layer is at least one layer, characterized in that the polycarbonate sheet.
According to claim 1,
The thickness of the sheet is a polycarbonate sheet, characterized in that 1 to 10 mm.
According to claim 1,
The UV wavelength blocked by the sheet is a polycarbonate sheet, characterized in that 280 to 350 nm.
The polycarbonate sheet according to claim 1 to 13
A polycarbonate sheet, characterized in that it is produced by at least one or more processes selected from the group consisting of coextrusion, coextrusion lamination, construction extrusion molding, sheet molding and multiple injection molding.
The method of claim 13,
In the case of the process by the coextrusion lamination, the residual coating layer not included in the extrudate is a polycarbonate sheet, characterized in that it is reused in the step of forming the polycarbon layer.
The method of claim 13,
In the case of the process by the coextrusion lamination, the lamination is at least one layer, and the thickness ratio of the polycarbonate layer and the coating layer is 1: 0.001 to 1, characterized in that the polycarbonate sheet.

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