KR100653504B1 - Light Diffusion Resin Composition - Google Patents

Abstract

The present invention relates to a light diffusing resin composition having a high diffusivity and a high light transmittance, and more particularly, by mixing two or more thermoplastic resins, the present invention can be molded into a product having a high diffusivity and a high light transmittance at the same time. It is related with the light-diffusion resin composition which can manufacture resin used suitably for the backlight of a display, a lighting apparatus, a signboard, etc.

Light Diffusion, Blends, Thermoplastics, Diffusion, Light Transmittance

Description

Light Diffusion Resin Composition

The present invention relates to a light diffusing resin composition having a high diffusivity and a high light transmittance, and more particularly, by mixing two or more thermoplastic resins, the present invention can be molded into a product having a high diffusivity and a high light transmittance at the same time. It is related with the light-diffusion resin composition which can manufacture resin used suitably for the backlight of a display, a lighting apparatus, a signboard, etc.

In general, light diffusion sheets have been used to make point or line light sources appear as uniform surface light sources. Such a light diffusion sheet requires high diffusivity in order to make the backlight or the contents of the rear surface visible from the outside and show uniform brightness, and at the same time, high light transmittance is required to increase the light efficiency (high brightness, low power consumption).

As a light-diffusion sheet conventionally used, For example, (1) The light-diffusion sheet obtained by shape | molding the transparent thermoplastic resin of Unexamined-Japanese-Patent No. 4-275501 in sheet form, and giving a surface the physical unevenness | corrugation, Or (2) a light diffusing sheet (film) obtained by coating a light diffusing layer made of a transparent resin containing fine particles on a transparent base film such as the polyester resin of JP-A-6-059108, or (3) The light-diffusion sheet obtained by melt-mixing the beads in the transparent resin of Unexamined-Japanese-Patent No. 6-123802, and extruding this, or (4) Two or more types of transparent as described in Unexamined-Japanese-Patent No. 9-311205. The light-diffusion sheet etc. which melt-mix a thermoplastic resin and have a matrix and a domain structure are mentioned.

The light diffusing sheets of (1) and (2) are surface light diffusing sheets which obtain a light diffusing effect by an uneven or coated light diffusing layer formed on the sheet surface. In the case of a light diffusion sheet that has a light diffusion effect due to surface irregularities, the sheet is more likely to be damaged during handling, and in particular, (2) is a type commonly used in small liquid crystal displays such as notebook computers. The light diffusion sheet of the type has a problem in that it is difficult to laminate a film required for high performance and multifunction in the liquid crystal display field. In addition, when the light diffusion layer is coated on the surface, there is a problem in that a problem such as peeling off of the coating layer is likely to occur due to a difference in thermal expandability with the substrate.

In addition, the light diffusion sheet provided by the method (3) or (4) has the advantage that a sheet having light diffusion characteristics can be obtained at once and a high diffusivity can be obtained. However, the inorganic filler added to give the light diffusivity to the light diffusing sheet of (3) has a disadvantage of significantly lowering mechanical properties such as transmittance and impact strength, and has a problem of abrasion of the processing equipment when used for a long time. The light diffusing sheet provided by the method of (4) has the advantage of obtaining a light diffusing sheet with a simple process and a lower cost than the above methods, but until now has a light diffusing characteristic of a level sufficient to be used as a commercial product The product is not produced. Although it is well known that light diffusion properties can be obtained by mixing two or more kinds of materials having different refractive indices, in order to obtain a product having a level of light diffusion properties that can be used as a commercial product, the refractive index difference and the domain between the two materials to be mixed are obtained. This is because the amount and size of the material to make the appropriate to be adjusted.

In order to solve the above problems, the present invention is that the light diffusing sheet having excellent characteristics is not produced in the method of manufacturing the light diffusing sheet of (4) which is conceptually excellent in the present invention. It was considered that the technique presented in the issue did not suggest suitable conditions, and therefore, a study was conducted to make a light diffusion resin composition that can be made into a product having excellent light diffusion properties. As a result, it was confirmed that a resin composition capable of simultaneously having high diffusivity and high light transmittance under completely different conditions from those disclosed in the above patents was completed, and the present invention was completed.

Accordingly, the present invention provides a high diffusion and high level that can be used as a commercial product when a resin prepared by mixing two or more thermoplastic resins is made into a product using a processing method such as extrusion molding, compression molding, or injection molding. An object of the present invention is to provide a resin composition capable of simultaneously having a light transmittance.

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention provides a light-diffusion resin composition consisting of a thermoplastic resin constituting a matrix and a thermoplastic resin constituting a matrix having a refractive index difference of 0.005 to 0.1.

In the above formula, R represents a difference in refractive index between the thermoplastic resin constituting the matrix and the thermoplastic resin constituting the domain, and C _d represents the concentration (% by weight) of the thermoplastic resin constituting the domain.

In addition, the present invention provides a light diffusion sheet manufactured by the light diffusion resin composition described above and having a total light transmittance of 60% or more and a light diffusivity of 70% or more.

Hereinafter, the present invention will be described in detail.

The present invention provides a resin in which at least two thermoplastic resins are mixed in a matrix structure with the matrix. The thermoplastic resin forming the matrix is a transparent thermoplastic resin or a thermoplastic resin capable of imparting transparency. Transparent here means that the total light transmittance is about 80% or more. As the transparent thermoplastic resin or a thermoplastic resin capable of imparting transparency, for example, poly methyl methacrylate, alkyl (meth) acrylate copolymer, methyl methacryl Methyl methacrylate-styrene copolymer, polycarbonate, poly vinyl chloride, styrene-acrylonitrile copolymer, cycloolefin copolymer (cyclo- olefin copolymers, cyclo-olefin polymers, poly acrylonitrile, polyesters or polystyrenes.

When the thermoplastic resin constituting the matrix is polymethyl methacrylate, the thermoplastic resin constituting the domain is methyl methacrylate-styrene copolymer, alkyl (meth) acrylate copolymer, cycloolefin copolymer, cycloolefin polymer, 1 type in the group consisting of polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polyester Can be selected.

When the thermoplastic resin constituting the matrix is an alkyl (meth) acrylate copolymer, the thermoplastic resin constituting the domain is methyl methacrylate-styrene copolymer, polymethyl methacrylate, cycloolefin copolymer, cycloolefin polymer, 1 type in the group consisting of polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polyester Can be selected.

When the thermoplastic resin constituting the matrix is a methyl methacrylate-styrene copolymer, the thermoplastic resin constituting the domain is a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a cycloolefin copolymer, a cycloolefin polymer, a poly Carbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, polyester and polystyrene More than one species may be selected.

When the thermoplastic resin constituting the matrix is polycarbonate, the thermoplastic resin constituting the domain is polymethyl methacrylate, alkyl (meth) acrylate copolymer, methyl methacrylate-styrene copolymer, cycloolefin copolymer, cyclo It may be selected from the group consisting of olefin polymers, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, polyesters and polystyrenes.

When the thermoplastic resin constituting the matrix is a cycloolefin copolymer or a cycloolefin polymer, the thermoplastic resin constituting the domain may be a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a methyl methacrylate-styrene copolymer, Polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, polyester and polystyrene One or more may be selected.

When the thermoplastic resin constituting the matrix is polyvinyl chloride, the thermoplastic resin constituting the domain is a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a methyl methacrylate-styrene copolymer, a cycloolefin copolymer, Cycloolefin polymer, polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, polyester and polystyrene One or more may be selected.

When the thermoplastic resin constituting the matrix is polyacrylonitrile, the thermoplastic resin constituting the domain is polymethyl methacrylate, methyl methacrylate-styrene copolymer, alkyl (meth) acrylate copolymer, cycloolefin copolymer , Cycloolefin polymer, polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polyester Can be selected.

When the thermoplastic resin constituting the matrix is a styrene-acrylonitrile copolymer, the thermoplastic resin constituting the domain is a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a methyl methacrylate-styrene copolymer, a cyclo Olefin copolymer, cycloolefin polymer, polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-maleic anhydride copolymer, polyester and polystyrene One or more may be selected.                     

When the thermoplastic resin constituting the matrix is polyester, the thermoplastic resin constituting the domain is polymethyl methacrylate, alkyl (meth) acrylate copolymer, methyl methacrylate-styrene copolymer, cycloolefin copolymer, cyclo Olefin polymer, polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polystyrene One or more may be selected.

When the thermoplastic resin constituting the matrix is polystyrene, the thermoplastic resin constituting the domain is polymethyl methacrylate, alkyl (meth) acrylate copolymer, methyl methacrylate-styrene copolymer, cycloolefin copolymer, cycloolefin. At least one selected from the group consisting of polymers, polycarbonates, polypropylenes, polyethylenes, polyvinyl chlorides, polyacrylonitriles, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, and polyesters.

As the polyester, polyethylene terephthalate is preferably used.

In addition, the thermoplastic resin forming the domain is preferably selected from thermoplastic resins having a refractive index difference of 0.005 to 0.1 from the thermoplastic resin forming the matrix, and more preferably selected from 0.01 to 0.08 thermoplastic resin. If the refractive index is smaller than this, it is difficult to obtain diffusion characteristics. If the refractive index is larger than this condition, the transmittance is decreased.

The content of the thermoplastic resin constituting the domain is a range of the appropriate level depending on the refractive index difference with the resin constituting the matrix. If the difference in refractive index is small, the content of the resin constituting the domain should be large. If the difference in refractive index is large, the content of the resin constituting the domain should be small. Accordingly, the inventors of the present invention have found out that it is desirable to select a resin under conditions satisfying the following equation in order to have excellent light diffusion characteristics.

[Equation 1]

In the above formula, R represents the difference in refractive index between the resin constituting the matrix and the resin constituting the domain, and C _d represents the weight% of the resin constituting the domain.

More preferably, it selects from the range which satisfy | fills following formula 2,

Most preferably, it selects in the range which satisfy | fills following formula (3).

The thermoplastic resin forming the domain satisfies the conditions set forth above, and can be used without particular limitation as long as it is a kind that can be processed at a temperature capable of processing the thermoplastic resin forming the matrix. However, in order to achieve the optimal light diffusion characteristics, it is necessary to adjust the appropriate content within the range given in the above formula according to the thickness of the light diffusion sheet as the final product. In addition, the thermoplastic resin forming the domain is preferably selected from resins having an average particle size of 0.5 μm to 50 μm when molded into a final product, and more preferably from 1 μm to 30 μm. It is suitable to use. In addition, when the thickness of the finally produced light diffusion sheet is less than 0.3mm or more than 5mm, the diffusion degree is reduced or the transmittance is reduced, so that it is difficult to exhibit excellent light diffusion characteristics under the above conditions, the light provided by the present invention. It is appropriate that the thickness of the final product made of the diffusion resin is 0.3 mm to 5 mm, more preferably 0.5 mm to 3 mm.

The resin provided in the present invention is mainly formed of two kinds of thermoplastic resins, but may be three or more kinds. In the case of three or more kinds, one of the resins forms a matrix and the remaining resins form a domain. The K [( R + 0.02) × C _d ] value is calculated using the average refractive index and the total weight ratio calculated in consideration of the weight ratio and the refractive index of each of the resins forming the domain.

The light-diffusion resin composition of this invention can add various additives within the range which does not impair the effect of this invention. Examples of the additive to be added include fluorescent brighteners, antioxidants, heat resistant agents, light resistant agents, weathering agents, antistatic agents and the like.

In order for the light diffusion sheet manufactured by the light diffusion resin composition of the present invention to be used as a light diffusion product, the total light transmittance is preferably 60% or more, and the light diffusivity is 70% or more, and the total light transmittance is 70% or more, The light diffusivity is more preferably 80% or more.

The following presents preferred examples and comparative examples to aid in understanding the invention. However, the following examples and comparative examples are provided only to more easily understand the present invention, and the present invention is not limited to the following examples and comparative examples.

EXAMPLE

The light diffusing characteristics of the light diffusing sheet prepared in each example were measured by using a haze transmittance meter (trade name: HR-100, Murakami Color Research Laboratory) according to JIS K 7105. Shown in

Example 1

Polymethyl methacrylate (PMMA) having a refractive index difference of 0.04 and a cycloolefin copolymer (COC, Ticona, Grade: 6017) were melt mixed at a weight ratio of 98/2 to obtain a light-diffusion resin in pellet form. The prepared pellets were dried in a dryer and then compressed into a sheet having a thickness of 0.7 mm using a heating press machine. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 2

Polymethyl methacrylate (PMMA) and cycloolefin copolymer (COC) having a refractive index difference of 0.04 were melt mixed at a weight ratio of 95/5 to prepare a light diffusion resin, and the sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.                     

Example 3

Polymethyl methacrylate (PMMA) and cycloolefin copolymer (COC) having a refractive index difference of 0.04 were melt mixed at a weight ratio of 90/10 to prepare a light diffusion resin, and the sheet having a thickness of 0.7 mm in the same manner as in Example 1 above. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 4

Polymethyl methacrylate (PMMA) and ethylene propylene copolymer (EPR) having a refractive index difference of 0.01 were melt mixed at a weight ratio of 90/10 to prepare a light diffusion resin, and the sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 5

Polymethyl methacrylate (PMMA) and polycarbonate (PC) having a refractive index difference of 0.1 were melt mixed at a weight ratio of 95/5 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. It was. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 6

Polycarbonate (PC) having a refractive index difference of 0.06 and a cycloolefin copolymer (COC) were melt mixed at a weight ratio of 95/5 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. . The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.                     

Example 7

Polycarbonate (PC) having a refractive index difference of 0.06 and a cycloolefin copolymer (COC) were melt mixed at a weight ratio of 90/10 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. . The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 8

Polycarbonate (PC) having a refractive index difference of 0.1 and polymethyl methacrylate (PMMA) were melt mixed at a weight ratio of 98/2 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. It was. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 9

Polycarbonate (PC) having a refractive index difference of 0.1 and polymethyl methacrylate (PMMA) were melt mixed at a weight ratio of 95/5 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. It was. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 10

Cycloolefin copolymer (COC) having a refractive index difference of 0.04 and polymethyl methacrylate (PMMA) were melt mixed at a weight ratio of 90/10 to prepare a light diffusion resin, and the sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.                     

Example 11

Methyl methacrylate-styrene copolymer (MS) having a refractive index difference of 0.05 and ethylene propylene copolymer (EPR) were melt mixed at a weight ratio of 95/5 to prepare a light diffusion resin, and 0.7 mm in the same manner as in Example 1. A sheet of thickness was produced. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 12

Polymethyl methacrylate (PMMA) and cycloolefin copolymer (COC) having a refractive index difference of 0.04 were melt mixed at a weight ratio of 98/2 to prepare a light diffusion resin, and the sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 13

Polymethyl methacrylate (PMMA) and cycloolefin copolymer (COC) having a refractive index difference of 0.04 were melt mixed at a weight ratio of 95/5 to prepare a light diffusion resin, and the sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 14

Polymethyl methacrylate (PMMA) and ethylene propylene copolymer (EPR) having a refractive index difference of 0.01 were melt mixed at a weight ratio of 95/5 to prepare a light diffusion resin, and the sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 15

Polymethyl methacrylate (PMMA) and ethylene propylene copolymer (EPR) having a refractive index difference of 0.01 were melt mixed at a weight ratio of 90/10 to prepare a light diffusion resin, and the sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 16

Polymethyl methacrylate (PMMA) and ethylene propylene copolymer (EPR) having a refractive index difference of 0.01 were melt mixed at a weight ratio of 80/20 to prepare a light diffusion resin, and the sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 17

Polycarbonate (PC) having a refractive index difference of 0.06 and a cycloolefin copolymer (COC) were melt mixed at a weight ratio of 98/2 to prepare a light diffusion resin, and a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. . The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 18

Cycloolefin copolymer (COC) having a refractive index difference of 0.04 and polymethyl methacrylate (PMMA) were melt mixed at a weight ratio of 90/10 to prepare a light diffusion resin, and a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Example 19

Polymethyl methacrylate (PMMA), ethylene propylene copolymer (EPR), and polycarbonate (PC) were melt mixed at a weight ratio of 91/8/1 to prepare a light diffusion resin, and the same method as in Example 1 was carried out to 2 mm. A sheet of thickness was produced. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

Comparative Example 1

Polymethyl methacrylate (PMMA) having a refractive index difference of 0.04 and a cycloolefin copolymer (COC) were melt mixed at a weight ratio of 99/1 to prepare a light diffusion resin, and the sheet having a thickness of 0.7 mm in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 0.06.

Comparative Example 2

Polymethyl methacrylate (PMMA) and ethylene propylene copolymer (EPR) having a refractive index difference of 0.01 were melt mixed at a weight ratio of 98/2 to prepare a light diffusion resin, and the sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 0.06.

Comparative Example 3

Polymethyl methacrylate (PMMA) and polycarbonate (PC) having a refractive index difference of 0.1 were melt mixed at a weight ratio of 88/12 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. It was. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 1.44.

[Comparative Example 4]

Polycarbonate (PC) having a refractive index difference of 0.06 and a cycloolefin copolymer (COC) were melt mixed at a weight ratio of 80/20 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. . The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 1.6.

[Comparative Example 5]

Polycarbonate (PC) having a refractive index difference of 0.1 and polymethyl methacrylate (PMMA) were melt mixed at a weight ratio of 99.5 / 0.5 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. It was. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 0.06.

Comparative Example 6

Polycarbonate (PC) having a refractive index difference of 0.1 and polymethyl methacrylate (PMMA) were melt mixed at a weight ratio of 88/12 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. It was. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 1.44.

Comparative Example 7

Polymethyl methacrylate (PMMA) and cycloolefin copolymer (COC) having a refractive index difference of 0.04 were melt mixed at a weight ratio of 80/20 to prepare a light diffusion resin, and the sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 1.2.

Comparative Example 8

Polymethyl methacrylate (PMMA) and ethylene propylene copolymer (EPR) having a refractive index difference of 0.01 were melt mixed at a weight ratio of 98/2 to prepare a light diffusion resin, and the sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. Was prepared. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 0.06.

Comparative Example 9

Polymethyl methacrylate (PMMA) and polycarbonate (PC) having a refractive index difference of 0.1 were melt mixed at a weight ratio of 90/10 to prepare a light diffusion resin, and a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. It was. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition outside the range suggested by the present invention under the condition that the K value is 1.2.                     

Comparative Example 10

Polycarbonate (PC) having a refractive index difference of 0.11 and ethylene propylene copolymer (EPR) were melt mixed at a 95/5 weight ratio to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. . The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition that the refractive index difference is out of the range proposed by the present invention.

Comparative Example 11

Polycarbonate (PC) having a refractive index difference of 0.11 and an ethylene propylene copolymer (EPR) were melt mixed at a 95/5 weight ratio to prepare a light diffusion resin, and a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2. This comparative example is a condition that the refractive index difference is out of the range proposed by the present invention.

Comparative Example 12

TiO ₂ was mixed with polymethyl methacrylate (PMMA) at a weight ratio of 99.9 / 0.1 to prepare a light diffusion resin, and a sheet having a thickness of 0.7 mm was prepared in the same manner as in Example 1. The total light transmittance and the light diffusivity of the prepared sheet were measured by the method described above and are shown in Table 2.

The types and amounts of the resins, the refractive index differences, the K values, and the thicknesses of the resins used as the matrix and the domain resin in the Examples and Comparative Examples are summarized in Table 1 below.                     

matrix domain Refractive index difference K [(R + 0.02) × C _d ] Thickness (mm) Suzy weight% Suzy weight% Example 1 PMMA 98 COC 2 0.04 0.12 0.7 Example 2 PMMA 95 COC 5 0.04 0.30 0.7 Example 3 PMMA 90 COC 10 0.04 0.60 0.7 Example 4 PMMA 90 EPR 10 0.01 0.30 0.7 Example 5 PMMA 95 PC 5 0.1 0.60 0.7 Example 6 PC 95 COC 5 0.06 0.40 0.7 Example 7 PC 90 COC 10 0.06 0.80 0.7 Example 8 PC 98 PMMA 2 0.1 0.24 0.7 Example 9 PC 95 PMMA 5 0.1 0.60 0.7 Example 10 COC 90 PMMA 10 0.04 0.60 0.7 Example 11 MS 95 EPR 5 0.05 0.35 0.7 Example 12 PMMA 98 COC 2 0.04 0.12 2 Example 13 PMMA 95 COC 5 0.04 0.30 2 Example 14 PMMA 95 EPR 5 0.01 0.15 2 Example 15 PMMA 90 EPR 10 0.01 0.30 2 Example 16 PMMA 80 EPR 20 0.01 0.60 2 Example 17 PC 98 COC 2 0.06 0.16 2 Example 18 COC 90 PMMA 10 0.04 0.60 2 Example 19 PMMA 91 EPR / PC 9 (8/1) 0.02 0.36 2 Comparative Example 1 PMMA 99 COC One 0.04 0.06 0.7 Comparative Example 2 PMMA 98 EPR 2 0.01 0.06 0.7 Comparative Example 3 PMMA 88 PC 12 0.1 1.44 0.7 Comparative Example 4 PC 80 COC 20 0.06 1.60 0.7 Comparative Example 5 PC 99.5 PMMA 0.5 0.1 0.06 0.7 Comparative Example 6 PC 88 PMMA 12 0.1 1.44 0.7 Comparative Example 7 PMMA 80 COC 20 0.04 1.20 2 Comparative Example 8 PMMA 98 EPR 2 0.01 0.06 2 Comparative Example 9 PMMA 90 PC 10 0.1 1.20 2 Comparative Example 10 PC 95 EPR 5 0.11 0.65 0.7 Comparative Example 11 PC 95 EPR 5 0.11 0.65 2 Comparative Example 12 PC 99.9 TiO ₂ 0.1 1.01 0.10 0.7

Total light transmittance (%) Transmittance> 60% Light Diffusion [haze] (%) Light Diffusion> 70% Example 1 91.7 ○ 79.1 ○ Example 2 88.7 ○ 83.6 ○ Example 3 85.4 ○ 83.8 ○ Example 4 91.1 ○ 77.8 ○ Example 5 73.3 ○ 73.3 ○ Example 6 78.7 ○ 83.8 ○ Example 7 73.2 ○ 83.9 ○ Example 8 75.9 ○ 72.1 ○ Example 9 62.0 ○ 83.7 ○ Example 10 88.7 ○ 83.4 ○ Example 11 76.7 ○ 83.8 ○ Example 12 75.3 ○ 83.7 ○ Example 13 66.0 ○ 84.1 ○ Example 14 89.7 ○ 82.9 ○ Example 15 86.7 ○ 83.4 ○ Example 16 80.7 ○ 83.8 ○ Example 17 64.4 ○ 82.6 ○ Example 18 64.4 ○ 84.1 ○ Example 19 86.2 ○ 83.4 ○ Comparative Example 1 91.9 ○ 68.1 × Comparative Example 2 92.2 ○ 59.3 × Comparative Example 3 57.9 × 83.7 ○ Comparative Example 4 59.1 × 83.9 ○ Comparative Example 5 85.3 ○ 23.8 × Comparative Example 6 58.7 × 83.8 ○ Comparative Example 7 59.4 × 84.1 ○ Comparative Example 8 92.1 ○ 67.6 × Comparative Example 9 48.8 × 83.8 ○ Comparative Example 10 57.9 × 83.6 ○ Comparative Example 11 39.6 × 83.3 ○ Comparative Example 12 54.8 × 83.4 ○

As can be seen from the results of Comparative Example 10 to Comparative Example 11, it was confirmed that the light transmittance was low when the difference in refractive index between the resin to be mixed is outside the appropriate range of 0.005 to 0.1. In addition, even if the refractive index is in the appropriate range when the concentration of the domain resin is too small (Comparative Examples 1, 2, 5 and 8), the light transmittance is high but the light diffusion is not properly, and the concentration of the domain resin is too high (compare Examples 3, 4, 6, 7 and 9) or Comparative Example 12 using TiO ₂ as the domain resin can also be seen that the light transmittance is low.

 As described in detail above, the light-diffusion resin composition according to the present invention selects two or more thermoplastic resins having a refractive index difference of an appropriate level (0.005 ~ 0.1) and mixes at an appropriate ratio according to the refractive index difference, high light transmittance and high It is possible to provide a light diffusing resin that can be molded into a product having a light diffusing degree.

Although the present invention has been described in detail with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the present invention, and such modifications and modifications fall within the scope of the appended claims. It is also natural.

Claims (14)

A light-diffusion resin composition comprising a thermoplastic resin constituting a matrix having a refractive index difference of 0.005 to 0.1 and a thermoplastic resin constituting a domain, and satisfying the following formula. [Equation 1]

In the above formula, R represents a difference in refractive index between the thermoplastic resin constituting the matrix and the thermoplastic resin constituting the domain, and C _d represents the concentration (% by weight) of the thermoplastic resin constituting the domain. The method of claim 1, The thermoplastic resin constituting the matrix is polymethyl methacrylate, and the thermoplastic resin constituting the domain is methyl methacrylate-styrene copolymer, alkyl (meth) acrylate copolymer, cycloolefin copolymer, cycloolefin polymer, poly At least one member of the group consisting of carbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polyester Light diffusion resin composition, characterized in that selected. The method of claim 1, The thermoplastic resin constituting the matrix is an alkyl (meth) acrylate copolymer, and the thermoplastic resin constituting the domain is methyl methacrylate-styrene copolymer, polymethyl methacrylate, cycloolefin copolymer, cycloolefin polymer, poly At least one member of the group consisting of carbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polyester Light diffusion resin composition, characterized in that selected. The method of claim 1, The thermoplastic resin constituting the matrix is a methyl methacrylate-styrene copolymer, and the thermoplastic resin constituting the domain is a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a cycloolefin copolymer, a cycloolefin polymer, a poly Carbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, polyester and polystyrene Light diffusion resin composition characterized by the above-mentioned. The method of claim 1, The thermoplastic resin constituting the matrix is a polycarbonate, and the thermoplastic resin constituting the domain is a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a methyl methacrylate-styrene copolymer, a cycloolefin copolymer, a cycloolefin. Light diffusion, characterized in that at least one selected from the group consisting of polymers, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, polyester and polystyrene Resin composition. The method of claim 1, The thermoplastic resin constituting the matrix is a cycloolefin copolymer or a cycloolefin polymer, and the thermoplastic resin constituting the domain is a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a methyl methacrylate-styrene copolymer, a poly Carbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, polyester and polystyrene Light diffusion resin composition characterized by the above-mentioned. The method of claim 1, The thermoplastic resin constituting the matrix is polyvinyl chloride, and the thermoplastic resin constituting the domain is polymethyl methacrylate, alkyl (meth) acrylate copolymer, methyl methacrylate-styrene copolymer, cycloolefin copolymer, cyclo 1 in the group consisting of olefin polymers, polycarbonates, ethylene propylene copolymers, ethylene octene copolymers, polypropylene, polyethylene, polyacrylonitrile, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, polyesters and polystyrenes Light diffusion resin composition characterized by the above-mentioned. The method of claim 1, The thermoplastic resin constituting the matrix is polyacrylonitrile, and the thermoplastic resin constituting the domain is polymethyl methacrylate, methyl methacrylate-styrene copolymer, alkyl (meth) acrylate copolymer, cycloolefin copolymer, At least one member of the group consisting of cycloolefin polymer, polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polyester Light diffusion resin composition, characterized in that selected. The method of claim 1, The thermoplastic resin constituting the matrix is a styrene-acrylonitrile copolymer, and the thermoplastic resin constituting the domain is a polymethyl methacrylate, an alkyl (meth) acrylate copolymer, a methyl methacrylate-styrene copolymer, and a cycloolefin. Copolymer, cycloolefin polymer, polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-maleic anhydride copolymer, polyester and polystyrene 1 or more types are selected, The light-diffusion resin composition characterized by the above-mentioned. The method of claim 1, The thermoplastic resin constituting the matrix is polyester, and the thermoplastic resin constituting the domain is polymethyl methacrylate, alkyl (meth) acrylate copolymer, methyl methacrylate-styrene copolymer, cycloolefin copolymer, cycloolefin. 1 from the group consisting of polymer, polycarbonate, ethylene propylene copolymer, ethylene octene copolymer, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polystyrene Light diffusion resin composition characterized by the above-mentioned. The method of claim 1, The thermoplastic resin constituting the matrix is polystyrene, and the thermoplastic resin constituting the domain is polymethyl methacrylate, alkyl (meth) acrylate copolymer, methyl methacrylate-styrene copolymer, cycloolefin copolymer, cycloolefin polymer. , Polycarbonate, polypropylene, polyethylene, polyvinyl chloride, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer and polyester, characterized in that at least one selected from the group consisting of Resin composition. The method according to any one of claims 2 to 11, The polyester is a light diffusion resin composition, characterized in that the polyethylene terephthalate. A light diffusion sheet prepared by the light diffusion resin composition according to claim 1, having a total light transmittance of 60% or more and a light diffusivity of 70% or more. The method of claim 13, The light diffusing sheet has a thickness of 0.3 mm to 5 mm.