Transparent plastic sheet for blocking ultraviolet and infrared rays

Abstract

To provide a transparent plastic sheet with an improved ultraviolet and infrared blocking rate while maintaining transparency.SOLUTION: Proposed is a transparent plastic sheet for blocking ultraviolet and infrared rays, the sheet including a base layer including a thermoplastic polymer and a skin layer provided on one or each side of the base layer and including a thermoplastic polymer, an ultraviolet blocking agent, an antioxidant, and an infrared blocking agent, in which the base layer and the skin layer are formed by the co-extrusion process.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a transparent plastic sheet for blocking ultraviolet and infrared rays. [Background technology]

[0002] Generally, polycarbonate sheets are widely used as a substitute for glass in building materials such as skylights, building lighting panels, roofing materials, canopies, windows or safety glass, swimming pools, indoor gymnasium roofs, greenhouses or soundproof walls.

[0003] Such polycarbonate sheets are usually produced by extrusion molding, and are characterized by excellent transparency and strength.

[0004] Sunlight is broadly divided into ultraviolet rays, visible light, and infrared rays, with ultraviolet rays accounting for approximately 6%, visible light for approximately 46%, and infrared rays for approximately 48%.

[0005] Infrared rays, which account for almost half of the sun's rays and do not contribute to lighting but instead cause heating, are classified according to wavelength into near infrared rays (0.75-3μm), infrared rays (3-25μm), and far infrared rays (over 25μm). Compared to visible light and ultraviolet rays, infrared rays have a stronger heating effect. For this reason, they are also called heat rays, but the radiant heat transmitted from the sun and heating elements to space is mainly due to infrared rays.

[0006] However, polycarbonate sheets that have been used in conventional outdoor structures have a low infrared blocking rate, and when the internal temperature of the structure rises in summer, the sheet bends due to thermal expansion and contraction.

[0007] In order to solve these problems, various methods have been tried to obtain a heat insulating effect, such as using a milky white polycarbonate sheet or laminating an infrared reflective film. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent No. 10-0900194 (Announced June 2, 2009) Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a transparent plastic sheet that has improved infrared and ultraviolet ray blocking rates while maintaining transparency.

[0010] Another object of the present invention is to provide a transparent plastic sheet having a superior infrared ray blocking rate by incorporating a specific combination of infrared ray blocking agents in the skin layer, as compared with the case where each of the agents is used alone. [Means for solving the problem]

[0011] In one aspect, the present invention provides a transparent plastic sheet for blocking infrared and ultraviolet rays, comprising a substrate layer containing a thermoplastic polymer, and a skin layer on one or both sides of the substrate layer, the skin layer containing a thermoplastic polymer, an ultraviolet ray blocking agent, an antioxidant, and an infrared ray blocking agent, the substrate layer and the skin layer being formed by a co-extrusion method.

[0012] The infrared ray blocking agent may be one or more selected from the group consisting of zinc oxide, tungsten oxide, and aluminum-doped tungsten oxide, and specifically, may contain 70 to 80% by weight of tungsten oxide and 20 to 30% by weight of aluminum-doped tungsten oxide.

[0013] The infrared ray blocking agent may be particles having a particle size of 1 nm to 100 μm.

[0014] The skin layer may contain 83 to 98% by weight of a thermoplastic polymer, 0.3 to 15% by weight of an ultraviolet ray blocking agent, 0.1 to 2% by weight of an antioxidant, and 0.01 to 0.5% by weight of an infrared ray blocking agent.

[0015] The skin layer may have a thickness of 0.01 to 0.5 mm.

[0016] The thermoplastic polymer may be at least one selected from the group consisting of polycarbonate, polyethylene terephthalate, polyethylene terephthalate glycol, polycyclohexylene dimethylene terephthalate glycol, polymethyl methacrylate, and polystyrene, and specifically may be polycarbonate. Effect of the Invention

[0017] The present invention can provide a transparent plastic sheet that maintains transparency while improving the ultraviolet and infrared ray blocking rate.

[0018] Furthermore, the present invention can provide a transparent plastic sheet having a superior infrared ray blocking rate compared to the case where a specific combination of infrared ray blocking agents is contained in the skin layer, compared to the case where each of the agents is used alone.

[0019] Furthermore, by manufacturing the ultraviolet and infrared blocking sheet by mixing a relatively low-cost infrared blocking agent, the manufacturing cost can be reduced. [Brief description of the drawings]

[0020] [Figure 1] 1 is a diagram showing a transparent plastic sheet for blocking ultraviolet and infrared rays according to one embodiment of the present invention. [Figure 2a] 1 shows the results of measuring infrared transmittance for different infrared cutoff agent components and contents. [Figure 2b] 1 shows the results of measuring infrared transmittance for different infrared cutoff agent components and contents. [Figure 2c]1 shows the results of measuring infrared transmittance for different infrared cutoff agent components and contents. [Diagram 3] This is the result of comparing the infrared transmittance when infrared blocking agents are used alone and in combination. [Figure 4] FIG. 1 is a diagram showing a test device for measuring the temperature rise suppression effect. [Diagram 5] FIG. 13 is a diagram showing an analysis of the temperature rise suppression effect. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in several different embodiments and is not limited to the embodiments described herein. Like reference numerals are used throughout the specification to refer to like parts.

[0022] In one aspect, the present invention provides a transparent plastic sheet 1 for blocking infrared and ultraviolet rays, comprising a substrate layer 2 containing a thermoplastic polymer, and a skin layer 3 on one or both sides of the substrate layer 2, the skin layer 3 containing a thermoplastic polymer, an ultraviolet ray blocking agent, an antioxidant, and an infrared ray blocking agent, the substrate layer 2 and the skin layer 3 being formed by a co-extrusion method.

[0023] As used herein, the term "coextrusion" can be used when two or more extruders are used to make extrusion coatings, films, or sheets, and refers to the general practice of adding one or more layers to create a multi-layer structure.

[0024] In the present specification, the co-extrusion is not particularly limited, and a sheet consisting of a substrate layer and a skin layer can be manufactured by a general co-extrusion process. In addition, in the co-extrusion process, a method in which the substrate layer and the skin layer extruded from two or more extruders meet in a feed block and are formed to a certain thickness by a calendar roll can be provided, or a method in which multiple nozzles are used to co-extrude through one extrusion die can be provided, but is not limited thereto.

[0025] As used herein, the term "thermoplastic polymer" refers to a polymer that melts when heat is applied and returns to a solid state when the temperature is sufficiently reduced.

[0026] The thermoplastic polymer may be at least one selected from the group consisting of polycarbonate (PC), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polycyclohexylene dimethylene terephthalate glycol (PCTG), polymethyl methacrylate (PMMA) and polystyrene (PS), and specifically may be polycarbonate.

[0027] The thickness of the base layer 2 is not particularly limited, but may be preferably 1 to 8 mm.

[0028] The skin layer 3 can be formed on one or both sides of the base layer 2, and can be formed on both sides to improve the efficiency of blocking ultraviolet and infrared rays.

[0029] The skin layer 3 may have a thickness of 0.01 to 0.5 mm, specifically 0.05 to 0.4 mm, and more specifically 0.05 to 0.2 mm.

[0030] If the thickness of the skin layer 3 is less than 0.01 mm, there is a problem in that the efficiency of blocking ultraviolet and infrared rays is reduced, whereas if it exceeds 0.5 mm, there is a problem in that the transparency is reduced.

[0031] The skin layer 3 may contain a thermoplastic polymer, an ultraviolet ray blocking agent, an antioxidant, and an infrared ray blocking agent, and specifically, may contain 83 to 98 weight % of a thermoplastic polymer, 0.3 to 15 weight % of an ultraviolet ray blocking agent, 0.1 to 2 weight % of an antioxidant, and 0.01 to 0.5 weight % of an infrared ray blocking agent.

[0032] The skin layer 3 may contain 83 to 98% by weight of a thermoplastic polymer, specifically 90 to 95% by weight.

[0033] If the content of thermoplastic polymer in the skin layer 3 is less than 83% by weight, the mechanical properties of the sheet may be reduced, and if it exceeds 98% by weight, there is a problem that the ultraviolet ray and ultraviolet ray blocking effect will be reduced due to the excessive content.

[0034] The thermoplastic polymer in the skin layer 3 may be the same as the thermoplastic polymer in the substrate layer 2 .

[0035] The skin layer 3 may contain 0.3 to 15% by weight of an ultraviolet ray blocking agent, specifically, 4 to 9% by weight.

[0036] If the content of the UV-blocking agent in the skin layer 3 is less than 0.3% by weight, the UV-blocking effect will not be achieved, and if it exceeds 15% by weight, the mechanical properties of the skin layer 3 and the sheet may be reduced.

[0037] When the content of the ultraviolet ray blocking agent is within the above range, an ultraviolet ray blocking efficiency of 70% or more can be achieved.

[0038] The ultraviolet ray blocking agent may be at least one selected from the group consisting of benzotriazole-based, hindered amine-based, benzophenone-based and salicylate-based agents.

[0039] Among the ultraviolet ray blocking agents, examples of the benzotriazole-based agents that can be used include those commercially available under the trade names Tinuvin (registered trademark) 234 (Basf), Tinuvin (registered trademark) 237 (Basf), Tinuvin (registered trademark) 239 (Basf), Tinuvin (registered trademark) 360 (Basf), Tinuvin (registered trademark) 1577 (Basf), SONGSORB (registered trademark) 2340 (Songwon Industrial), SONGSORB (registered trademark) 2370 (Songwon Industrial), SONGSORB (registered trademark) 3290 (Songwon Industrial), SONGSORB (registered trademark) 3600 (Songwon Industrial) and SONGSORB (registered trademark) 1577 (Songwon Industrial), and examples of the salicylate-based agents that can be used include the trade name HOSTAVIN B-CAP (manufacturer: Clariant Co., Ltd.).

[0040] The skin layer 3 may contain 0.1 to 2% by weight of an antioxidant, specifically 0.3 to 1% by weight.

[0041] If the content of the antioxidant in the skin layer 3 is less than 0.1% by weight, the desired antioxidant effect cannot be achieved, whereas if it exceeds 2% by weight, the physical properties of the skin layer 3 may be deteriorated.

[0042] As the antioxidant, it is preferable to use a mixture of a phenol-based primary antioxidant and a phosphorus-based secondary antioxidant, and in this case, each of the antioxidants can be used in an amount of 0.05 to 1% by weight.

[0043] The phenolic primary antioxidant is commercially available under the trade name Irganox 1076 (BASF), and the phosphorus-based secondary antioxidant is commercially available under the trade name Irgafos 168 (BASF).

[0044] The skin layer 3 may contain 0.01 to 0.5% by weight of the infrared ray blocking agent, specifically, 0.04 to 0.15% by weight.

[0045] If the content of the infrared-cutting agent in the skin layer 3 is less than 0.01% by weight, the infrared-cutting effect cannot be achieved, and if it exceeds 0.5% by weight, the expected effect is not achieved compared to the amount added, and there is a problem of reduced transparency.

[0046] The infrared ray cutoff agent may be one or more selected from the group consisting of zinc oxide, tungsten oxide, and aluminum-doped tungsten oxide, and specifically, the infrared ray cutoff agent may be 70 to 80% by weight of tungsten oxide and 20 to 30% by weight of aluminum-doped tungsten oxide, and more specifically, 75 to 80% by weight of tungsten oxide and 20 to 25% by weight of aluminum-doped tungsten oxide. When the mixture ratio of tungsten oxide and aluminum-doped tungsten oxide is within the above range, it can exhibit a superior infrared ray cutoff effect compared to using them alone.

[0047] The infrared ray blocking agent may have a particulate shape, specifically, the infrared ray blocking agent may have a particle size of 1 nm to 100 μm, more specifically, the particle size of 1 nm to 10 μm.

[0048] When the infrared and ultraviolet ray blocking transparent plastic sheet 1 according to the present invention is made of the components and composition within the above-mentioned ranges, it can exhibit excellent ultraviolet and infrared ray blocking efficiency.

[0049] The present invention will be described in more detail below using examples. These examples are merely for the purpose of more specifically explaining the present invention, and it will be obvious to those skilled in the art that the scope of the present invention is not limited by these examples.

[0050] <Test Example> Test Example 1: Analysis of UV and infrared blocking effect According to the ingredients shown in Table 1 below, a plastic sheet was produced by co-extrusion so that skin layers were formed on both sides of the substrate layer, and the ultraviolet and infrared ray blocking effect was measured.

[0051] To confirm the effects of ultraviolet and infrared rays, a polycarbonate sheet was used as a control.

[0052] In this case, the infrared ray blocking agent used had a particle size of 50 μm, and the plastic sheet was manufactured so that the skin layer had a thickness of 0.25 mm.

[0053] The ultraviolet and infrared blocking effect was measured by measuring the transmittance in 2 nm units in the wavelength range of 300 nm to 2,500 nm using UV-VIS equipment, and the blocking rate in the infrared and ultraviolet regions was calculated.

[0054] [Table 1]

[0055] 2a to 2c, comparing Samples 1 to 9, it can be seen that as the content of the infrared ray blocking agent in the skin layer increases, the infrared ray blocking effect increases proportionately.

[0056] In addition, when comparing tungsten oxide, aluminum-doped tungsten oxide, and zinc oxide, the sheet containing tungsten oxide was the most excellent, followed by aluminum-doped tungsten oxide and zinc oxide, in that order.

[0057] Based on the above results, it is determined that in order to cut infrared rays (wavelengths of 780 to 2500 nm) by 70% or more while maintaining a visible light transmittance (wavelengths of 400 to 780 nm) of 70% or more, it is preferable to use 0.075% or more of tungsten oxide.

[0058] 3, it can be seen that the infrared ray blocking efficiency of the sheet using a mixture of infrared ray blocking agents is more excellent than that of sheets using tungsten oxide, aluminum-doped tungsten oxide, or zinc oxide alone. In particular, it can be seen that sample 10, which is a mixture of tungsten oxide and aluminum-doped tungsten oxide in a ratio of 8:2, is superior to all the mixed sheets as well as to the samples using each of the individual compounds.

[0059] As a result, the present invention can exhibit the most excellent ultraviolet and infrared ray blocking effect by incorporating tungsten oxide and aluminum-doped tungsten oxide as infrared ray blocking agents in the skin layer in a weight ratio of 8:2.

[0060] Test example 2: Analysis of temperature rise suppression effect The temperature rise suppression effects of Sample 10 in Test Example 1 and the control group were analyzed.

[0061] Sample 10 and a control were placed in a closed space, and the temperature rise suppression effect was measured for 120 minutes by irradiating them with an infrared lamp.

[0062] Referring to FIG. 5, it can be seen that the temperature of the control group rose to 51.2° C. after 120 minutes, while that of sample 10 rose to 41.1° C.

[0063] As a result, it can be confirmed that the plastic sheet of the present invention suppresses the temperature rise by about 10.1°C compared to the control, a general polycarbonate sheet.

[0064] The present invention described above with reference to the accompanying drawings may be modified and altered in various ways by those skilled in the art, and such modifications and alterations should also be construed as falling within the scope of the present invention. [Explanation of symbols]

[0065] 1. Transparent plastic sheet for blocking ultraviolet and infrared rays 2 Base material layer 3 Skin Layer

Claims

1. A substrate layer comprising a thermoplastic polymer; a skin layer on one or both sides of the base layer, the skin layer including a thermoplastic polymer, an ultraviolet ray blocking agent, an antioxidant, and an infrared ray blocking agent; The transparent plastic sheet for blocking infrared and ultraviolet rays, wherein the base layer and the skin layer are formed by a co-extrusion method.

2. 2. The transparent plastic sheet for blocking infrared and ultraviolet rays according to claim 1, wherein the infrared ray blocking agent is at least one selected from the group consisting of zinc oxide, tungsten oxide, and aluminum-doped tungsten oxide.

3. 3. The infrared and ultraviolet ray blocking transparent plastic sheet according to claim 2, wherein the infrared ray blocking agent comprises 70 to 80% by weight of tungsten oxide and 20 to 30% by weight of aluminum-doped tungsten oxide.

4. 2. The infrared and ultraviolet ray blocking transparent plastic sheet according to claim 1, wherein the infrared ray blocking agent is a particle having a particle size of 1 nm to 100 μm.

5. The skin layer comprises 83 to 98% by weight of a thermoplastic polymer, 0.3 to 15% by weight of an ultraviolet ray blocking agent, 0.1 to 2% by weight of an antioxidant, and 0.01 to 0.5% by weight of an infrared ray blocking agent. The transparent plastic sheet for infrared and ultraviolet ray blocking according to claim 1.

6. 2. The infrared and ultraviolet ray blocking transparent plastic sheet according to claim 1, wherein the skin layer has a thickness of 0.01 to 0.5 mm.

7. 2. The transparent plastic sheet for blocking infrared and ultraviolet rays according to claim 1, wherein the thermoplastic polymer is at least one selected from the group consisting of polycarbonate, polyethylene terephthalate, polyethylene terephthalate glycol, polycyclohexylene dimethylene terephthalate glycol, polymethyl methacrylate, and polystyrene.

8. 8. The infrared and ultraviolet ray blocking transparent plastic sheet according to claim 7, wherein the thermoplastic polymer is polycarbonate.

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