KR20220104890A - Eco-friendly light diffusion sheet and manufacturing method for the same - Google Patents

Abstract

The disclosed content relates to an eco-friendly light diffusion sheet harmless to environments by applying biomass-derived polyethylene terephthalate glycol and a manufacturing method thereof. The eco-friendly light diffusion sheet is made of a single substrate having embossed upper and lower surfaces, respectively, wherein the substrate may include 100 parts by weight of biomass-derived polyethylene terephthalate glycol, 0.1 to 5 parts by weight of a dispersing agent, 0.1 to 2 parts by weight of an antioxidant, and 0.05 to 1 part by weight of an ultraviolet absorber.

Description

Eco-friendly light diffusion sheet and its manufacturing method {ECO-FRIENDLY LIGHT DIFFUSION SHEET AND MANUFACTURING METHOD FOR THE SAME}

The present disclosure relates to an eco-friendly light diffusion sheet using biomass-derived polyethylene terephthalate glycol and a method for manufacturing the same.

Unless otherwise indicated herein, the material described in this section is not prior art to the claims of this application, and inclusion in this section is not an admission that it is prior art.

In general, the light diffusion sheet is used for display devices such as TFT-LCD backlight units and small and medium-sized mobile devices such as TVs, laptops, and tablets. is required In addition, it should have light resistance and weather resistance so as not to be deformed or discolored when exposed to high temperature and humidity including sunlight. Such a light-diffusion sheet is manufactured in a sheet shape by mixing a thermoplastic resin such as an acrylic resin, polystyrene, or polycarbonate with a light-diffusing agent.

As the acrylic resin, polymethyl methacrylate having good transparency, light resistance and light transmittance is mainly used. Polymethyl methacrylate is advantageous for improving light transmittance and light diffusivity, but has limitations in improving physical properties such as mechanical strength or moisture absorption resistance. there is Polystyrene has disadvantages in that it has poor impact resistance, weather resistance and heat resistance, low process efficiency, and poor light resistance, weather resistance and moldability compared to acrylic resins.

On the other hand, Patent Document 1 and Patent Document 2 disclose an example of applying a polypropylene resin known as an eco-friendly material that is easy to recycle. Polypropylene resin is lightweight, has excellent transparency, and has the same level of weather resistance as polymethyl methacrylate, so it can be applied as a light diffusion sheet, but mechanical properties such as impact strength are poor, and physical properties such as total light transmittance are still There are insufficient problems. Therefore, we are focusing on product research and development to improve these problems and produce better products.

Republic of Korea Patent Registration No. 10-1980050 (2019.05.17) Republic of Korea Patent Registration No. 10-1973598 (2019.04.23)

An object of the present invention is to provide an eco-friendly light diffusion sheet that is not only harmless to the environment by applying biomass-derived polyethylene terephthalate glycol but also has excellent physical properties such as luminance and a manufacturing method thereof.

In addition, it is not limited to the technical problems as described above, and it is obvious that another technical problem may be derived from the following description.

According to an embodiment of the disclosure, the eco-friendly light diffusion sheet is made of a single substrate having embossed on the upper and lower surfaces, respectively, and the substrate is 100 parts by weight of biomass-derived polyethylene terephthalate glycol, 0.1 to 5 parts by weight of a diffusion agent, It contains 0.1 to 2 parts by weight of an antioxidant and 0.05 to 1 parts by weight of a UV absorber, the average particle diameter of the diffusing agent is 0.5 to 6 μm, and the refractive index is 1.5 or less.

In addition, the embossing may be formed by extrusion by a pair of embossing rolls having embossed patterns formed on the outer circumferential surface.

In addition, the surface roughness (Ra) of the embossing may be 1 ~ 10㎛.

In addition, the diffusing agent may be silicone beads or polymethyl methacrylate beads.

In addition, the thickness of the substrate may be 1-3 mm.

According to another embodiment of the disclosure, the method for manufacturing an eco-friendly light diffusion sheet includes (a) as a raw material, 100 parts by weight of biomass-derived polyethylene terephthalate glycol, 0.1 to 5 parts by weight of a diffusion agent, 0.1 to 2 parts by weight of an antioxidant, And after mixing 0.05 to 1 part by weight of a UV absorber, melting and molding, (b) melting and extruding the molded body to form a sheet, and (c) embossing the extruded sheet in the step (b) on the outer circumferential surface and passing between a pair of embossed rolls with patterns to form embossing on the upper and lower surfaces of the sheet, respectively.

In addition, in step (a), the diffusing agent is a silicon bead or polymethyl methacrylate bead, the average particle diameter is 0.5 ~ 6㎛, the refractive index may be 1.5 or less.

In addition, the melting and molding in step (a) may be carried out by a twin-screw extruder at a temperature condition of 150 ~ 250 ℃.

In addition, the twin-screw extruder includes a feeder to which the mixture is input, a supply region for transporting the mixture, a compression region for melt-compressing the mixture transported through the supply region, and a transport region for transporting the mixture by maintaining pressure and temperature and a die for discharging the mixture and two screws made of may be 200 ~ 220 ℃.

According to one embodiment disclosed in the present specification, the eco-friendly light diffusion sheet and its manufacturing method have an eco-friendly effect by applying a biomass-derived polyethylene terephthalate glycol.

In addition, by applying a diffusing agent having an average particle diameter of 0.5 to 6 μm, there is an effect of excellent luminance and haze.

1 is a perspective view showing an eco-friendly light diffusion sheet according to an embodiment of the content disclosed in the present specification.
FIG. 2A is a cross-sectional view taken along line A-A' of FIG. 1 .
Figures 2b and 2c is an embodiment showing the form of various embossing.
3 is a schematic view showing a method of forming an embossing.
4 is a process diagram for explaining a method of manufacturing an eco-friendly light diffusion sheet according to another embodiment of the content disclosed in the present specification.
5 is a schematic view showing a method of manufacturing an eco-friendly light diffusion sheet.

Hereinafter, with reference to the accompanying drawings, the configuration and effects of preferred embodiments of the disclosed subject matter will be described. For reference, in the following drawings, each component is omitted or schematically illustrated for convenience and clarity, and the size of each component does not reflect the actual size. In addition, the same reference numerals refer to the same components throughout the specification, and reference numerals for the same components in individual drawings will be omitted.

1 is a perspective view showing an eco-friendly light diffusion sheet according to an embodiment of the content disclosed in the present specification, FIG. 2a is a cross-sectional view taken along line A-A' of FIG. 1, and FIGS. 2b and 2c are embodiments showing the form of various embossing Example, Figure 3 is a schematic diagram showing a method of forming an embossing.

Hereinafter, an eco-friendly light diffusion sheet according to an embodiment of the disclosed contents will be described with reference to FIGS. 1 to 3 .

1 to 3 , the eco-friendly light diffusion sheet 10 disclosed herein may be made of a single substrate in which embossing 11 is formed on the upper and lower surfaces, respectively.

On the other hand, the embossing 11 is formed by extrusion by a pair of embossing rolls 300 having embossed patterns formed on the outer circumferential surface, and the embossing 11 of the upper and lower surfaces has a diameter L1 and a height as shown in FIG. 2A . (h1) may be made to be symmetrical to each other, and as shown in FIG. 2b, the embossing 11' of the upper and lower surfaces may be made asymmetrical to each other. In addition, as shown in Figure 2c, the embossing (11”) diameter (L3) of the lower surface may be made different from the embossing (11”) diameter (L2) of the upper surface, and in this embodiment, the embossing 11” of the lower surface ) diameter (L3) may be formed larger than the diameter (L2) of the embossing (11 ″) of the upper surface. The heights (h2, h3) may also be applied in proportion to the diameters (L2, L3) of the embossing (11″), but may be applied to have the same heights (h2, h3). The embossing 11 is not flat and has a curve, so that it is possible to provide roughness to the surface and prevent scratches at the same time. At this time, the surface roughness (Ra) may be 1 ~ 10㎛, preferably 2 ~ 6㎛.

The substrate is formed to a thickness (T) of 1 to 3 mm, preferably 1.5 to 2.5 mm, and includes a biomass-derived polyethylene terephthalate glycol (PETG), a diffusing agent, an antioxidant, and an ultraviolet absorber.

Biomass-derived polyethylene terephthalate glycol (PETG) is a biomass-derived material derived from corn and wheat, 5 to 30% by weight, preferably 9 to 15% by weight, based on the total weight. It can be an environmentally friendly raw material that has heat resistance at high temperatures such as 80~110℃ and excellent chemical resistance and processability. The total light transmittance of the biomass-derived polyethylene terephthalate glycol may be 90% or more, the haze may be 1.0% or less, and the Rockwell hardness may be 115 HRC or more.

The biomass-derived polyethylene terephthalate glycol may be included in an amount of 100 parts by weight.

The diffusing agent is a material used to uniformly diffuse the transmitted light, and silicon beads or polymethyl methacrylate beads, preferably silicon beads, may be used. For example, silicon beads having an average particle diameter of 0.5 to 6 μm, preferably 0.5 to 1.5 μm, and a refractive index of 1.5 or less, are preferably used. It becomes small and there is a fear that the light diffusivity required as the light diffusing sheet cannot be satisfied. If it exceeds 6 μm, not only the thickness of the light diffusing sheet increases but also uniform diffusion of light may be difficult. Therefore, when the diffusing agent satisfies the above-mentioned range, it is possible to better diffuse the light beam.

Such a dispersing agent may be included in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 1 parts by weight. If the diffusing agent is less than 0.1 parts by weight, it may be difficult to implement a desired surface roughness, and if it exceeds 5 parts by weight, it may be difficult to uniformly diffuse the transmitted light.

The antioxidant is a material used to prevent the light diffusion sheet from being easily oxidized by reacting with air, and from deterioration in quality, for example, at least one of phenolic, amine, sulfur, phosphate, and phosphorus is selected. can be used, and a mixture of phenolic and phosphorus in a weight ratio of 1:1 to 4 can be used. For example, as a phenolic type, tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) ) propionate) can be used, and tris (2,3-di-t-butylphenyl) phosphite) can be used as phosphorus, and among commercially available antioxidants, phenol Irganox 1076 (BASF), AO-60/AO-60G (ADEKA), ETHANOX ^® 310 (ALBEMARLE), etc. As a phosphate system, Irgafos 168 (BASF), ETHAPHOS ^TM 368 (ALBEMARLE), Hostanox ^® P-EPQ ^® FF (Clariant), etc.

These antioxidants may be included in an amount of 0.1 to 2 parts by weight, preferably 0.3 to 0.5 parts by weight. This means that when the antioxidant is less than 0.1 parts by weight, oxidation of the light diffusion sheet progresses and it may be difficult to maintain physical properties for a long period of time. This is not desirable because it can be

The ultraviolet absorber is a material used to improve the weather resistance of the composition and reduce yellowing caused by ultraviolet rays generated from a light source, for example, a benzophenone-based, cyanoacrylate-based, sarichireto-based, and nickel complex salt-based material. At least one selected from among may be used, but as long as it is a material capable of absorbing a wavelength in the range of 250 to 800 nm, its use is not significantly limited. Among commercially available antioxidants, Hostabin ^® B-cap ^TM (Clariant) can be used.

This ultraviolet absorber may be included in an amount of 0.05 to 1 parts by weight, preferably 0.1 to 0.3 parts by weight. This is not preferable because when the UV absorber is less than 0.05 parts by weight, the effect of improving weather resistance is insignificant, and yellowing may occur under the influence of UV rays, and if it exceeds 1 part by weight, deterioration of physical properties may occur.

In this embodiment, additives may be further included within the range that does not affect the physical properties of the light-diffusion sheet, and the additives include a light stabilizer, a blowing agent, a plasticizer, a lubricant, a flame retardant, a pigment, an antibacterial agent, a nucleating agent, and inorganic particles. At least one of the following can be used.

Hereinafter, a method of manufacturing an environmentally friendly light diffusion sheet disclosed in the present specification will be described in detail with reference to the drawings.

4 is a process diagram for explaining a method of manufacturing an eco-friendly light-diffusion sheet according to another embodiment of the present disclosure, and FIG. 5 is a schematic diagram illustrating a method of manufacturing an eco-friendly light-diffusing sheet.

4 and 5, after mixing 100 parts by weight of biomass-derived polyethylene terephthalate glycol, 0.1 to 5 parts by weight of a diffusion agent, 0.1 to 2 parts by weight of an antioxidant, and 0.05 to 1 parts by weight of a UV absorber as a raw material, Melting and molding (S10).

100 parts by weight of biomass-derived polyethylene terephthalate glycol, 0.1 to 5 parts by weight of a diffusing agent, preferably 0.5 to 1 parts by weight, 0.1 to 2 parts by weight of an antioxidant, preferably 0.3 to 0.5 parts by weight, and 0.05 to 1 part by weight of an ultraviolet absorber Parts by weight, preferably 0.1 to 0.3 parts by weight, may be mixed, and the reason for limiting the content of the raw material has been described in detail above, so it will be omitted.

Then, the mixed mixture may be put into the twin-screw extruder 100 to be melted and molded into a pellet-shaped molded product at a temperature of 150 to 250°C.

The twin-screw extruder 100 includes a feeder 101 to which the mixture is fed, a supply region 102a for transporting the mixture, and a compression region 102b for melt-compressing the mixture transported through the supply region 102a and , two screws 102 consisting of a transfer region 102c for transporting the mixture by maintaining pressure and temperature, a barrel 103 provided to surround the two screws 102, and a die for discharging the mixture ( 104) can be achieved.

For example, the supply region (102a) may be 150 ~ 170 ℃, the compression region (102b) is 180 ~ 200 ℃, the transfer region (102c) may be 200 ~ 220 ℃.

Then, the molded body is melted and extruded to form a sheet (S20).

The molded article formed in step S10 may be melted and extruded using the T-die 200 to form a sheet. The T-die 200 is not particularly limited in its use as long as it is typically used for manufacturing a film or sheet, but for example, the T-die 200 includes a die body, a heater provided on one side of the die body, It may be composed of a cooling unit bolted to one side of the heater and a seat adjusting unit bolted to a lower side of the cooling unit.

Finally, the sheet is passed between a pair of embossing rolls 300 having embossed patterns formed on the outer circumferential surface to form embossing 11 on the upper and lower surfaces of the sheet (S30).

The sheet extruded in step S20 may be passed between a pair of embossing rolls 300 having embossed patterns on the outer circumferential surface to form embossing 11 on the upper and lower surfaces of the sheet, respectively. As long as it is used to manufacture a film or sheet, there is no restriction on its use.

The embossing 11 of the upper and lower surfaces may be made symmetrical to each other, or may be made asymmetrical to each other. In addition, the embossing (11”) diameter (L3) of the lower surface may be made different from the embossing (11”) diameter (L2) of the upper surface, and in this embodiment, the embossing (11”) diameter (L3) of the lower surface is the upper surface of the emboss (11 ″) may be formed larger than the diameter (L2). The heights (h2, h3) may also be applied in proportion to the diameters (L2, L3) of the embossing (11″), but may be applied to have the same heights (h2, h3). The embossing 11 is not flat and has a curve, so that it is possible to provide roughness to the surface and prevent scratches at the same time. At this time, the surface roughness (Ra) may be 1 ~ 10㎛, preferably 2 ~ 6㎛.

Example 1. Preparation of light-diffusing sheet

15% by weight of biomass After mixing each of the diffusion agent 1, the antioxidant, and the non-ray absorbent in the amounts shown in Table 1 in 100 parts by weight of biomass-derived polyethylene terephthalate glycol, melting and molding at a temperature of 200 to 245° C. using a twin-screw extruder did. Then, the molded body was formed into a sheet with a thickness of 1.5 mm using a T-die and passed between a pair of embossing rolls having embossed patterns on the outer circumferential surface to prepare a light-diffusing sheet having embossed on the upper and lower surfaces, respectively.

As the diffusion agent 1, silicon beads having an average particle diameter of 1.1 μm and a refractive index of 1.43 were used.

division Example 1 Example 2 Biomass-derived PETG 100 parts by weight 100 parts by weight diffuser 1 0.5 parts by weight 1 part by weight diffuser 2 - - inorganic particles - - antioxidant 0.4 parts by weight 0.4 parts by weight UV absorber 0.2 parts by weight 0.2 parts by weight

Comparative Examples 1 to 4. Preparation of light-diffusing sheet

15% by weight of biomass The same method as in Example 1, except that each 100 parts by weight of biomass-derived polyethylene terephthalate glycol was mixed with the diffusion agent 1 or the diffusion agent 2, inorganic particles, antioxidant, and the exclusion ray absorbent in the amounts shown in Table 2 below. A light-diffusing sheet was prepared.

As the diffusion agent 2, silicon beads having an average particle diameter of 1.9 μm and a refractive index of 1.43 were used.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Biomass-derived PETG 100 parts by weight 100 parts by weight 100 parts by weight 100 parts by weight diffuser 1 - - 1 part by weight 1 part by weight diffuser 2 0.5 parts by weight 1 part by weight - - inorganic particles - - 0.1 parts by weight 0.5 parts by weight antioxidant 0.4 parts by weight 0.4 parts by weight 0.4 parts by weight 0.4 parts by weight UV absorber 0.2 parts by weight 0.2 parts by weight 0.2 parts by weight 0.2 parts by weight

Experimental Example 1. Evaluation of physical properties

In order to confirm the physical properties of Examples 1 to 2 and Comparative Examples 1 to 4, each light diffusion sheet was cut to 50 mm in width and 50 mm in length, and then measured based on ASTM D 1003 method, but the haze was measured using a Haze measuring device (Haze). meter, NDH-7000, NIPPON DENSHOKU INDUSTRIES CO., LTD.) and color difference values were measured using a spectrophotometer (CM-3700d, Konica Minolta).

In addition, after cutting the light diffusion sheet to be 300 mm wide and 300 mm long, the luminance was measured with a luminance meter at a position 30 cm away from the light source using a direct-type LED lamp, and whether a hot spot was visible at a position 15 cm away from the light source. was confirmed. When hot spot visibility was not recognized, it was marked as good, and when hot spot visibility was weak or recognized, it was marked as poor, and the results are shown in Table 3.

division Haze (%) Luminance (cd/m ² ) shielding power color coordinate deviation Example 1 97 108 Good Good Example 2 96 100 Good Good Comparative Example 1 96 100 error Good Comparative Example 2 96 94 error Good Comparative Example 3 95 83 Good error Comparative Example 4 93 61 error error

Referring to Table 3, in the case of Examples 1 and 2, it was confirmed that the luminance and shielding power were superior to those of Comparative Examples 1 and 2 having the same composition ratio, which was due to the particle size of the silicon beads. could In the case of Comparative Example 3, the haze and shielding power were similar to those of Example 2, but the luminance was sharply decreased, and color coordinate deviation was also issued. In Comparative Example 4, not only the haze, luminance, and color coordinate values abruptly dropped, but also the shielding power deviation occurred.

Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and represent all the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modifications that can be substituted for them at the time of filing the present application. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following claims rather than the detailed description, and the meaning and scope of the claims and their All changes or modifications derived from the concept of equivalents should be construed as being included in the scope of the present invention.

10, 10', 10”: Eco-friendly light diffusing sheet 11, 11', 11”: Emboss
100: twin screw extruder 101: feeder
102: two screws 103: barrel
104: die 200: T-die
300: a pair of embossed rolls

Claims (9)

Doedoe made of a single substrate having embossed on the upper and lower surfaces, respectively,
The article is
100 parts by weight of biomass-derived polyethylene terephthalate glycol;
0.1 to 5 parts by weight of a dispersing agent;
0.1 to 2 parts by weight of antioxidant; and
Including; 0.05 to 1 part by weight of a UV absorber;
The average particle diameter of the diffusion agent is 0.5 ~ 6㎛, eco-friendly light diffusion sheet, characterized in that the refractive index is 1.5 or less.
According to claim 1,
The embossing is an eco-friendly light-diffusing sheet, characterized in that it is formed by extrusion by a pair of embossing rolls in which the embossing pattern is formed on the outer circumferential surface.
The method of claim 1,
The eco-friendly light-diffusing sheet, characterized in that the surface roughness (Ra) of the emboss is 1 ~ 10㎛.
According to claim 1,
The diffusion agent is an environmentally friendly light diffusion sheet, characterized in that the silicone bead or polymethyl methacrylate beads.
According to claim 1,
The eco-friendly light-diffusing sheet, characterized in that the thickness of the substrate is 1-3mm.
(a) as a raw material, 100 parts by weight of biomass-derived polyethylene terephthalate glycol, 0.1 to 5 parts by weight of a diffusion agent, 0.1 to 2 parts by weight of an antioxidant, and 0.05 to 1 parts by weight of a UV absorber after mixing;
(b) melting and extruding the molded article into a sheet; and
(c) passing the extruded sheet in step (b) between a pair of emboss rolls having embossed patterns on the outer circumferential surface to form embossing on the upper and lower surfaces of the sheet, respectively; manufacturing method.
7. The method of claim 6,
In the step (a), the diffusion agent is a silicon bead or polymethyl methacrylate bead, the average particle diameter is 0.5 ~ 6㎛, and the refractive index of the manufacturing method of an eco-friendly light diffusion sheet, characterized in that 1.5 or less.
7. The method of claim 6,
Melting and molding in step (a) is a method of manufacturing an eco-friendly light-diffusion sheet, characterized in that it is carried out by a twin-screw extruder at a temperature condition of 150 ~ 250 ℃.
9. The method of claim 8,
The twin screw extruder,
a feeder into which the mixture of the raw materials is mixed;
two screws comprising a supply region for transporting the mixture, a compression region for melt-compressing the mixture transported through the supply region, and a transport region for transporting the mixture while maintaining pressure and temperature;
a barrel provided to surround the two screws; and
A die for discharging the mixture; including,
The supply region is 150 ~ 170 ℃, the compression region is 180 ~ 200 ℃, the transport region is a method of manufacturing an eco-friendly light diffusion sheet, characterized in that 200 ~ 220 ℃.

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