JP3751548B2 - Master pellet and its molded body - Google Patents

Description

【００４２】
【表２】

【００４３】
【発明の効果】
本発明のマスターペレットを用いた成形体は、光線透過特性を維持しつつ、光拡散性に優れているため、照明器具カバー、導光板、プロジェクションテレビ用スクリーンなど、高い光拡散性および光透過性を要求される分野で特に有効である。
【図面の簡単な説明】
【図１】タイプＡに分類される異形樹脂粒子の側面図である。
【図２】タイプＢに分類される異形樹脂粒子の側面図である。
【図３】タイプＣに分類される異形樹脂粒子の側面図である。
【図４】自動変角光度計で測定した光拡散性データの比較を表すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a master pellet obtained by blending irregularly shaped resin particles with a base resin, and a molded body made of the master pellet.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, optical parts such as lighting fixture covers, lenses, light guide plates, video discs, projection TV screens, cosmetic containers, vending machine front plates, signboards, product displays, tabletop containers, etc. polycarbonate resin, polystyrene resin, acrylic Thermoplastic resins such as resins are used. In these applications, a light diffusing substance is added to a transparent thermoplastic resin in order to increase commercial value such as design.
[0003]
As the light diffusing substance, inorganic particles such as glass, calcium carbonate, and silica, or resin particles such as acrylic resin and polystyrene are used. However, when inorganic particles are used, there is a problem that it is difficult to uniformly disperse and the light transmittance is remarkably lowered. On the other hand, when resin particles are used, they have good affinity with thermoplastic resins and are easy to disperse uniformly, and the refractive index is close to that of the base resin. It is preferably used without lowering. However, even when resin particles are used, it is still unsatisfactory to meet the increasing demand for projection television screens (maintaining light transmission characteristics and excellent light diffusibility).
[0004]
Therefore, an object of the present invention is to obtain a molded article that is excellent in light diffusibility and has a lower total light transmittance than the conventional one and a master pellet for producing the molded article.
[0005]
[Means for Solving the Problems]
As a result of earnest research to solve the above-mentioned problems, the present inventor has found that a master having good light diffusibility and light transmission characteristics can be obtained by blending irregular shaped resin particles having a specific shape with the base resin. The inventors have found that pellets can be obtained and have completed the present invention.
[0006]
According to the present invention, the base resin is formed of two curved surfaces or one curved surface and one flat surface, and has a boundary line between both surfaces, and in the side view when this boundary is a lateral direction, When the maximum particle diameter in the horizontal direction is D and the maximum height in the vertical direction is d, the formula:
0.05 ≦ d / D ≦ 0.8 (I)
The master pellet which mix | blended the irregular-shaped resin particle which satisfy | fills, and the molded object which consists of this master pellet are provided.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the deformed resin particles blended in the base resin are formed of two curved surfaces or one curved surface and one flat surface, and have a boundary line between both surfaces.
Note that the curved surface and the flat surface here are usually uniform surfaces having no chippings or dents, but within a range where the effect of the present invention is recognized, there are a few nonuniform portions such as chips and dents. It doesn't matter.
[0008]
The boundary line can be confirmed when the irregular shaped resin particles are observed with an electron micrograph or the like. In other words, the contrast of the irregularly shaped resin particles is different on the SEM photograph and is a portion recognized as a boundary line. The width of the portion is about 1/10 or less of the maximum height of the particles, and more specifically about 1/20 or less. Even if the boundary line is partially missing and discontinuous as a whole, the boundary line of the present invention is used as long as the effect of the present invention is exhibited.
[0009]
The irregular shaped resin particles in the present invention are composed of two surfaces, and at least one surface is a curved surface. Therefore, characteristics that are not found in ordinary disk-like particles, flat particles, plate-like particles, such as light scattering properties, etc. It has friction characteristics such as optical characteristics and slipperiness. In addition, since the other surface is a flat surface or a curved surface having a large radius of curvature, it has characteristics not found in ordinary spherical particles, for example, excellent drop-off resistance.
[0010]
If the boundary line between the two surfaces forming the resin particle is defined as the horizontal direction, the plan view of the irregular resin particle in the present invention viewed from above is usually circular or substantially circular. And the shape of the irregular shaped resin particle in this invention is divided roughly into the following three types by the shape of two surfaces located on both sides across this boundary line.
[0011]
That is, when the deformed resin particles are viewed from the side with the boundary line in the horizontal direction, one convex surface appears above the boundary line, and the other convex surface appears below the boundary line (hereinafter, “ "Type A": see Fig. 1), a type in which one plane coincides with the boundary line, and one convex surface appears above or below the boundary line (hereinafter referred to as "Type B": see Fig. 2), and one A convex surface and a single concave surface are roughly divided into three types (hereinafter referred to as “type C”: see FIG. 3) that appear in the same direction, for example, below, with a boundary line in between.
[0012]
In the side view when the boundary line is in the horizontal direction, the irregular shaped resin particles in the present invention preferably satisfy the following formula where D is the maximum particle diameter in the horizontal direction and d is the maximum height in the vertical direction. .
0.05 ≦ d / D ≦ 0.8 (I)
0.1 μm ≦ D ≦ 500 μm (II)
[0013]
And in order for the master pellet of this invention and a molded object to show the outstanding optical characteristics (haze, diffusivity, etc.), when the maximum distance from the boundary line of a deformed resin particle to each surface is set to a and b, respectively, Those satisfying the formula are more preferable.
0.3 ≦ d / D ≦ 0.8 (III)
0 ≦ a / b ≦ 0.3 (IV)
(However, 0 ≦ a <b)
[0014]
For the above purpose, those satisfying the following formula are more preferable.
0.4 ≦ d / D ≦ 0.6 (III ′)
0 ≦ a / b ≦ 0.2 (IV ′)
(However, 0 ≦ a <b)
[0015]
Moreover, in order for the master pellet and the molded body of the present invention to exhibit more excellent optical properties (haze, diffusibility), it is preferable that the type A deformed resin particles satisfy the following formula.
0.05 ≦ d / D ≦ 0.8 (I)
0.3 ≦ a / b ≦ 1 (V)
(However, 0 <a ≦ b)
[0016]
For the above purpose, those satisfying the following formula are more preferable.
0.2 ≦ d / D ≦ 0.5 (I ′)
0.4 ≦ a / b ≦ 1 (V ′)
(However, 0 <a ≦ b)
[0017]
In addition, each numerical value of said D, d, a, and b was obtained by observing the irregular-shaped resin particle in this invention with an electron microscope or an optical microscope, or measuring or calculating by those image analysis methods. The average means the number average value.
[0018]
Although it does not specifically limit as a material which comprises the irregular shape resin particle in this invention, For example, a poly (meth) acrylic acid ester-type resin, a polystyrene resin, (meth) acrylic acid ester-styrene copolymer resin, a polyester-type resin, a silicone type Examples thereof include resins and polyolefin resins.
The deformed resin particles may or may not be crosslinked, but are preferably crosslinked when solvent resistance is required. The irregular shaped resin particles may contain a trace amount of additives such as an ultraviolet absorber, a heat stabilizer, and a colorant.
[0019]
The method for producing the irregular shaped resin particles is not particularly limited, and examples thereof include suspension polymerization and emulsion polymerization.
For details of the method for producing irregular shaped resin particles, the following production examples should be referred to.
[0020]
The base resin into which the irregular resin particles are blended is not particularly limited as long as it is a normal thermoplastic resin. For example, (meth) acrylic resin, (meth) acrylic acid alkyl-styrene copolymer resin, polycarbonate resin, A polyester resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, etc. are mentioned. In particular, when transparency is required, (meth) acrylic resin, (meth) alkyl acrylate-styrene copolymer resin, polycarbonate resin, and polyester resin are preferable. These base resins can be used alone or in combination of two or more.
The base resin may contain a trace amount of additives such as an ultraviolet absorber, a heat stabilizer, a colorant, and a filler.
[0021]
The master pellet of the present invention is produced by melt-kneading irregular shaped resin particles and a base resin, and by a molding method such as extrusion molding or injection molding.
The blending ratio of the irregular shaped resin particles in the master pellet is not particularly limited, but is about 0.1 to 60% by weight, preferably about 0.3 to 30% by weight, and more preferably about 0.4 to 10% by weight. If the blending ratio exceeds 60% by weight, it is not preferable because it becomes difficult to produce master pellets. On the other hand, if it is less than 0.1% by weight, the effect of the present invention is lowered, which is not preferable.
[0022]
The molded body of the present invention is produced by, for example, extrusion molding, injection molding or press molding of the master pellet obtained as described above. At that time, a base resin may be newly added. The addition amount of the base resin is preferably added so that the blending ratio of the deformed resin particles contained in the finally obtained molded product is about 0.1 to 60% by weight. At the time of molding, for example, a trace amount of additives such as an ultraviolet absorber, a heat stabilizer, a colorant, and a filler may be added.
[0023]
The master pellet and the molded product of the present invention are those obtained by blending any one of three types of irregularly shaped resin particles (type A, type B, type C), or a combination of two or more. Moreover, in the range which does not inhibit the effect of this invention, in addition to the irregular shaped resin particle in this invention, you may mix | blend a true spherical resin particle and an inorganic particle. However, in that case, the effect obtained by adding the irregular shaped resin particles in the present invention may be reduced, so that it should be noted.
[0024]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these Examples.
[0025]
Production Example 1
A dispersion medium in which 5 g of magnesium pyrophosphate is produced as a suspension stabilizer for 200 g of water by a metathesis method is placed in a 500 ml separable flask, 0.04 g of sodium lauryl sulfate as a surfactant, and water-soluble polymerization prohibited As an agent, 0.02 g of sodium nitrite was dissolved.
Separately, 90 g of styrene, 9 g of divinylbenzene, 10 g of dimethylpolysiloxane [viscosity at 25 ° C .: 1000 cSt] as a liquid compound, 0.5 g of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator A monomer composition prepared by uniformly mixing and dissolving was prepared.
[0026]
The monomer composition was added to the above dispersion medium and finely dispersed by stirring at 8000 rpm for about 10 seconds with a homomixer (ULKA TURRAX T-25 manufactured by IKA), and the droplet diameter of the monomer composition was adjusted to 15 μm. . A stirring blade, a thermometer, and a reflux condenser were attached to the above separable flask, and after replacing with nitrogen, the flask was placed in a constant temperature water bath at 60 ° C. In the separable flask, stirring was continued at a stirring speed of 200 rpm, and suspension polymerization was performed for 10 hours after the temperature of the dispersion liquid in which the monomer composition was finely dispersed reached 60 ° C.
[0027]
Next, the reaction solution was cooled, and hydrochloric acid was added until the pH of the slurry reached about 2, thereby decomposing the suspension stabilizer. The resin particles were suction filtered with a Buchner funnel using filter paper and washed with 1.2 liters of ion exchange water to remove the suspension stabilizer. The dehydrated cake after suction filtration was dried and then dispersed in cyclohexane, and suction filtration was repeated several times to obtain the desired deformed resin particles (type B).
Table 1 shows parameters of the shape of the resin particles.
[0028]
In addition, the parameter of the shape of the irregular shaped resin particles is arbitrarily selected from 50 resin particles from the electron micrograph, the diameter of the particles is measured, the number average center particle diameter is calculated, and the center particle diameter For 20 resin particles belonging to the upper and lower 30% ranges, the maximum particle diameter D in the horizontal direction when the boundary line is set in the horizontal direction, the maximum height d in the vertical direction of the particle, and the maximum distance from the boundary line to each surface A and b were measured, and average values of d / D and a / b were calculated.
[0029]
Production Example 2
Modified resin particles (type A) were obtained in the same manner as in Production Example 1, except that styrene was changed to 72 g, divinylbenzene was changed to 8 g, and dimethylpolysiloxane (viscosity at 25 ° C .: 1000 cSt) was changed to 20 g.
Table 1 shows parameters of the shape of the resin particles.
[0030]
Production Example 3
Modified resin particles (type C) were obtained in the same manner as in Production Example 1, except that styrene was changed to 83.7 g, divinylbenzene was changed to 9.3 g, and dimethylpolysiloxane (viscosity at 25 ° C .: 1000 cSt) was changed to 8 g. It was.
Table 1 shows parameters of the shape of the resin particles.
[0031]
Comparative production example 1
A polymerization vessel equipped with a stirrer and a thermometer was charged with 500 g of deionized water in which 0.05 g of sodium lauryl sulfate was dissolved, and 50 g of tricalcium phosphate was dispersed therein. Into this was added a mixed solution prepared by dissolving 0.5 g of benzoyl peroxide and 0.5 g of azobisisobutyronitrile in 85 g of styrene and 15 g of divinylbenzene. The liquid was dispersed by a K homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) and the droplets were adjusted to about 15 μm. Next, the polymerization reactor was heated to 65 ° C. and subjected to suspension polymerization while stirring, and then cooled. The suspension was filtered, washed, and dried to obtain true spherical resin particles.
Table 1 shows parameters of the shape of the resin particles.
[0032]
Example 1
0.5 parts by weight of the irregularly shaped resin particles (type A) obtained in Production Example 2 are added to 100 parts by weight of methyl methacrylate resin (MG-5 manufactured by Sumitomo Chemical Co., Ltd.), and after blending, are added to the extruder. Feeding to obtain master pellets.
The pellets were supplied to an injection molding machine and injection molded to obtain a light diffusing plate having a length of 100 mm, a width of 50 mm, and a thickness of 2 mm.
[0033]
The light diffusibility and light transmittance of this light diffusing plate were measured by using an automatic variable angle photometer ("GP-200" manufactured by Murakami Color Research Laboratory Co., Ltd.), and parallel rays were incident on the molding plate as a sample vertically. The angle dependency was measured, and the relative transmitted light intensity at each angle of 0 ° to 90 ° was measured with the transmitted light intensity in the 0 ° (front) direction as 100. This measurement data is shown in FIG. Further, the total light transmittance and haze were measured by a haze meter (based on “NDH-2000” JIS K7105 manufactured by Nippon Denshoku Co., Ltd.). The measured data are shown in Table 2.
[0034]
Example 2
A light diffusing plate was obtained in the same manner as in Example 1 except that the irregular shaped resin particles (type B) obtained in Production Example 1 were used. Table 2 shows measurement data of total light transmittance and haze of this light diffusion plate.
[0035]
Example 3
A light diffusing plate was obtained in the same manner as in Example 1 except that the irregular shaped resin particles (type C) obtained in Production Example 3 were used. Table 2 shows measurement data of total light transmittance and haze of this light diffusion plate.
[0036]
Example 4
A light diffusing plate was obtained in the same manner as in Example 1 except that the odd-shaped resin particles (type B and type A) obtained in Production Example 1 and Production Example 2 were mixed at a ratio of 1: 1. Table 2 shows measurement data of total light transmittance and haze of this light diffusion plate.
[0037]
Example 5
A light diffusing plate was prepared in the same manner as in Example 1 except that the irregular shaped resin particles (type B) obtained in Production Example 1 and the true spherical particles obtained in Comparative Production Example 1 were mixed at 7: 3. Obtained. Table 2 shows measurement data of total light transmittance and haze of this light diffusion plate.
[0038]
Comparative Example 1
A light diffusing plate was obtained in the same manner as in Example 1 except that the resin particles (true spherical shape) obtained in Comparative Production Example 1 were used. FIG. 4 shows measurement data of this light diffusion plate by an automatic variable angle photometer, and Table 2 shows measurement data of total light transmittance and haze.
[0039]
As is clear from FIG. 4, the light diffusion plate (Example 1) using the irregularly shaped resin particles of type A has a higher angle than that using the true spherical particles having substantially the same particle diameter (Comparative Example 1). It can be seen that the transmitted light intensity in the region is high, and as a result, the light diffusibility is excellent. Moreover, it can be seen from Table 2 that the total light transmittance is almost the same and the haze is slightly high, so that the light diffusibility is excellent while maintaining the light transmittance.
[0040]
Further, from Table 2, the light transmittance using the irregular shaped resin particles of type B (Example 2) and type C (Example 3) is similar to that of Comparative Example 1 in the same manner. Since the haze is high, it can be seen that the light diffusibility is excellent while maintaining the light transmittance.
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
【The invention's effect】
Since the molded body using the master pellet of the present invention is excellent in light diffusibility while maintaining light transmission characteristics, it has high light diffusibility and light transmittance such as a lighting fixture cover, a light guide plate, and a projection television screen. It is particularly effective in the field where it is required.
[Brief description of the drawings]
FIG. 1 is a side view of deformed resin particles classified into type A. FIG.
FIG. 2 is a side view of deformed resin particles classified into type B.
FIG. 3 is a side view of deformed resin particles classified into type C.
FIG. 4 is a graph showing a comparison of light diffusivity data measured with an automatic goniophotometer.

Claims (7)

In the base resin, it is formed with two curved surfaces or one curved surface and one flat surface, and has a boundary line between both surfaces. Where D is the maximum height in the vertical direction and d is the formula:
0.05 ≦ d / D ≦ 0.8 (I)
Master pellets blended with irregular shaped resin particles. The master pellet according to claim 1, wherein the deformed resin particles are particles formed of two convex surfaces. The master pellet according to claim 1, wherein the odd-shaped resin particles are particles formed of one convex surface and one flat surface. The master pellet according to claim 1, wherein the deformed resin particles are particles formed of one convex surface and one concave surface. The master pellet in any one of Claims 1-4 which mix | blended 0.1 to 60weight% of the irregular-shaped resin particle. The master pellet according to any one of claims 1 to 5, wherein the base resin is any one of (meth) acrylic resin, (meth) acrylic acid alkyl-styrene copolymer resin, polycarbonate resin, and polyester resin. The molded object obtained using the master pellet in any one of Claims 1-6.

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