KR20080057593A - Silicon bead with high quality luminance and lightfastness, method for preparing the same and light-diffusing plate using the same - Google Patents

Abstract

A silicone particle is provided to show excellent luminance and lightfastness and improved compatibility with a resin and workability by introducing a hydroxy group into the surface of a polyorganosilsesquioxane particle. A silicone particle is characterized in that it is surface treated to have an OH index value of 0.7-1.0, wherein the OH index value is calculated by dividing Si-OH peak of [Abs.(at 3,350-3,400-3,450 cm^-1)] into Si-CH3 peak of [Abs.(at 2,920-2,970-3,020 cm^-1)]. A method for preparing the silicone particle comprises the steps of: (a) drying polyorganosilsesquioxane latex to prepare a powder type silicone particle; and (b) drying or sintering the powder type silicone particle at a temperature of 200-400 deg.C for 0.5-3 hours. A light diffusing plate comprises 0.1-10 parts by weight of the silicone particle as a diffuser regarding 100 parts by weight of a thermoplastic resin. Further, an average diameter of the silicone particle is 0.1 to 20mum.

Description

Silicon Fine Particles with Excellent Brightness and Light Resistance, Manufacturing Method and Its Light Diffusion Plate {Silicon Bead with High Quality Luminance and Lightfastness, Method for Preparing the Same and Light-Diffusing Plate Using the Same}

Field of invention

The present invention relates to a silicon fine particle having excellent high brightness and light resistance as a diffusing agent, a manufacturing method thereof, and a light diffusion plate using the same. More specifically, the present invention provides a silicon particle having excellent brightness and light resistance and improved compatibility and workability with a resin by providing a hydroxyl group having a constant concentration on the surface of the particle through surface treatment, a manufacturing method thereof, and a light diffusion plate using the same. It is about.

Background of the Invention

Silicone-based fine particles such as silica and polysilsesquioxane generally have excellent compatibility with various polymer resins and organic substances, and thus are diverse as additives for paints, plastics, rubber, paper, coating liquids, and active agents to improve driving stability of high-definition video tapes. Is being used.

Particularly, the polyorganosilsesquioxane fine particles have a three-dimensional network structure but have excellent fluidity and compatibility with resins and have an optically low refractive index. It is attracting attention as an apparatus backlight, a diffusing agent of a light-diffusion plate, or an additive of a light guide plate.

Such silicon fine particles are subjected to hydrolysis and condensation reaction mechanisms using methyltrialkoxysilane monomers, as shown in Japanese Patent Application Laid-Open No. 54-72300, Japanese Patent Laid-Open No. 63-077940, Japanese Patent Laid-Open No. 10-045914, and Japanese Patent Laid-Open No. 2000-186148. It is variously manufactured by the sol-gel method which consists of these. However, when the silicon fine particles are used as the light diffusing agent, the light diffusivity due to the difference in refractive index with the resin is well expressed, but the light transmittance is greatly reduced, so that the light emitted from the light source is transmitted as much as possible, that is, the effective use of the light (luminance) ) Has the problem of falling.

In order to solve this problem, Japanese Patent Laid-Open No. 2006-10819, Japanese Patent Laid-Open No. Hei 1-172801, Japanese Patent Laid-Open No. Hei 1-269902, and Japanese Patent Laid-Open No. Hei 10-88008 adjust the ratio and components of the resin composition to improve luminance characteristics. How to do it. However, the method of controlling the ratio and components of the resin composition as described above is limited, and a new brightness and light resistance improvement method through controlling the properties of the diffusing agent itself is required.

Accordingly, the inventors of the present invention impart a hydroxyl group having a constant concentration to the surface of the particles of polyorganosilsesquioxane particles by surface treatment, and thus have excellent brightness and light resistance, and also improve the compatibility and workability with resins, and their preparation. It is time to develop a method.

An object of the present invention is to provide silicon fine particles having excellent brightness and light resistance.

Another object of the present invention is to provide a method for producing silicon fine particles having excellent brightness and light resistance through surface treatment on the surface of the particle.

Still another object of the present invention is to provide a silicon fine particle having improved compatibility and workability with a resin through a surface treatment operation on the particle surface.

Still another object of the present invention is to provide a light diffusion plate to which the silicon fine particles of the present invention are applied.

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

Summary of the Invention

The silicon fine particles of the present invention are surface treated to have an OH index value in the range of 0.7 to 1.0.

The silicon fine particles are prepared by surface-treating the powder-type polyorganosilsesquioxane particles to adjust the hydroxyl concentration so that the OH index value is in the range of 0.7 to 1.0.

In one embodiment of the present invention, the silicon microparticles are dried on polyorganosilsesquioxane latex to produce powdered silicon microparticles, and the powdery silicon microparticles are dried or sintered to adjust the hydroxyl concentration on the particle surface. It is manufactured by.

The silicon fine particles prepared by the above method are used as a diffusing agent because of excellent brightness and light resistance, compatibility with other resins, and workability, and are used for manufacturing a light diffusion plate together with a thermoplastic resin.

Detailed Description of the Invention

Silicon microparticles according to the invention is characterized in that the surface treatment so that the OH index value by the following formula has a range of 0.7 to 1.0.

OH index = [Abs. (At 3350-3400-3450 cm ^-1 )] / [Abs. (At 2920-2970-3020 cm ^-1 )]

[Abs. (At 3350-3400-3450 cm ^-1 )]: Si-OH peak

[Abs. (At 2920-2970-3020 cm ^-1 )]: Si-CH ₃ peak.

The OH index is in the range of 3350 to 3400 to 3450 cm ^-1 by the infrared spectrum. Si-OH peak value from 2920 to 2970 to 3020 cm ^-1 In range Si-CH ₃ peak Divided by the value . The adsorption concentration of the surface hydroxyl group is analyzed by IR analysis, and the OH index value can be obtained according to the above formula. By this measuring method, an optimal hydroxyl concentration range can be measured and analyzed. In the present invention, the OH index value is preferably 0.7 to 1.0.

When the OH index value exceeds 1.0, a large amount of hydroxyl groups are present on the surface, which increases the affinity with moisture, thereby decreasing compatibility with the resin, and causes workability such as water vapor generation during press injection work to be significantly reduced. If the OH index value is less than 0.7, the luminance is reduced.

Therefore, the optical properties of the particles themselves can be improved by granting Lewis / Bronsted acid properties of the polyorganosilsesquioxane (silicon) particle surface and the resin by providing an appropriate amount of hydroxyl group by controlling the effective OH index value.

The structure of a general polyorganosilsesquioxane is represented as RSiO _1.5 and is characterized by no hydroxyl group. The polyorganosilsesquioxane of the present invention has a repeating unit represented by the following formula (1).

[Formula 1]

RSiO _1.5-x (OH) _x

R represents an alkyl group having 1 to 6 carbon atoms, a vinyl group, an aryl group, and an alkyl substituted aryl group, wherein 0 <x <1.5.

The R is preferably a methyl group, an ethyl group, or a phenyl group, and particularly preferably a methyl group. The range of x in General formula (1) is 0 <x <1.5. Adsorption x concentration of the surface hydroxyl group can be analyzed by IR analysis to obtain the OH index value according to the above formula.

The silicon fine particles according to the present invention are prepared by controlling the concentration of hydroxyl groups on the surface of the particle so that the OH index value according to the above formula is surface treated with the powder-type polyorganosilsesquioxane particles.

The surface treatment may be heat treatment, chemical treatment or the like, and is preferably heat treatment at 200 to 400 ° C, more preferably at 200 to 300 ° C.

The powder-type polyorganosilsesquioxane particles are prepared using monomoloalkyl organosilanes as described in Japanese Patent Application Laid-Open Nos. 54-72300, 63-7777940, 10-045914 and 2000-186148. It can be prepared by a variety of sol-gel method, and is not limited to a specific manufacturing method.

In one embodiment of the present invention, the method for producing the silicon microparticles is to dry the polyorgano silsesquioxane latex to produce a silicon powder in the form of powder, and to dry or sinter the silicon particles in the powder form of OH index value And adjusting the hydroxyl concentration on the surface of the particle to have a range of 0.7 to 1.0.

The polyorganosilsesquioxane latex may be prepared by a sol-gel process using an organoalkoxy silane, but is not necessarily limited thereto.

The prepared polyorganosilsesquioxane latex may be recovered as silicon powder in the form of white powder first dried using a spray dryer at a temperature condition of 80 to 200 ° C.

In another embodiment of the present invention, the prepared polyorganosilsesquioxane latex is purified after the primary dewatered sludge using a centrifuge, filter press, vibrating screen, etc. after washing with water, and then the temperature ranges from 80 to 200 ° C. It can be recovered as white powdery silicon fine particles dried using a spin flash dryer, a vacuum dryer, or the like.

The silicon fine particles in powder form obtained above have a water content of about 5%, preferably 3% or less, and are made of the silicon fine particles of the present invention through a secondary drying or sintering process.

The hydroxyl concentration is adjusted through the drying or sintering process, and the drying or sintering process is performed at 200 to 400 ° C. The treatment time is 30 minutes to 3 hours, preferably 1 hour to 3 hours.

In one embodiment of the present invention, the silicon particles in powder form are dry sintered at 200-400 ° C. for 30 minutes to 3 hours in a calcinater such as a kiln rotary dryer and a convection oven. OH index value is adjusted in the range of 0.7 to 1.0.

The prepared surface-treated polyorganosilsesquioxane fine particles have an average particle diameter of 0.1-20 탆.

The polyorganosilsesquioxane microparticles | fine-particles which were obtained in this way will express the outstanding brightness | luminance and light resistance property when used for the manufacture of a light-diffusion plate as a light-diffusion agent.

In the present invention, the light diffusion plate is particularly suitable for the diffusion plate used in LCD-TV.

In one embodiment of the present invention, the light diffusing plate is composed of 0.1 to 10 parts by weight of the polyorganosilsesquioxane fine particles with respect to 100 parts by weight of the thermoplastic resin.

The manufacturing method of the light diffusing plate can be easily carried out by those skilled in the art.

When the thermoplastic resin is added to the thermoplastic resin such as vinyl chloride resin, styrene resin, styrene-acrylonitrile resin, acrylic resin, acrylic-styrene resin, ester resin, ABS resin or polycarbonate resin Since the transmittance is lowered, it may be used as a diffusion agent having excellent brightness and light resistance of the diffusion plate used in LCD-TV.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example 1

420 g of methyltrimethoxysilane was dispersed in 2580 ml of distilled water and stirred for 1 hour. Then, the pH was adjusted to 10 by adding ammonia water, restirring for 1 hour, and the silicone latex was synthesized by standing for 2 hours at room temperature. The latex thus synthesized was recovered to about 200 g of white particulate sludge through a filtration and washing process using a centrifuge. The polymethoxysilsesquioxane sludge was recovered as a white silicon powder through a primary drying process using a spin flash dryer at an inlet temperature of 160 ° C and an outlet temperature of 80 ° C. The secondary surface treatment was performed in a vacuum dryer at 200 ° C. for 2 hours to give a hydroxyl group as a concentration. As a result, polyorganosilsesquioxane fine particles having an OH index value of 0.88 were obtained.

Example 2

370 g of methyl trimethoxysilane and 50 g of methyl trichlorosilane were stirred with 2580 ml of ion-exchanged water for 1 hour, and then the pH was adjusted to 10 by adding ammonia water to react for 4 hours. Thereafter, 200 g of a white powder was recovered by filtration, washing with water and drying with a spray dryer. This silicon sludge was put into a spin flash dryer under the conditions of Example 1 and recovered in the form of white silicon powder. The secondary surface treatment was performed in a kiln rotary dryer under conditions of 200 ° C. and 40 minutes to give a hydroxyl group having an effectively controlled concentration to the recovered silicon powder surface. As a result, the OH index value of 0.93 was obtained. Polyorganosilsesquioxane microparticles | fine-particles could be obtained.

Example 3

370 g of 3-mercaptopropyltrimethoxysilane was dispersed in 2580 ml of distilled water, and 50 g of 3-aminopropylmethoxysilane was added thereto, followed by standing at room temperature for 6 hours. Thereafter, about 200 g of polymethoxysilsesquioxane particulate sludge was recovered by filtration and washing with a centrifugal separator. This silicon sludge was put into a spin flash dryer at a temperature of 160 ° C. and recovered as a white silicon powder. In order to give a controlled hydroxyl group to the surface of the silicon fine particles thus recovered, the surface treatment was performed in a kiln rotary dryer in a kiln rotary dryer at a temperature of 300 ° C. for 40 minutes, resulting in an OH index of 0.80. Polyorganosilsesquioxane fine particles having a

Example 4

370 g of 3-mercaptopropyltrimethoxysilane was dispersed in 2580 ml of distilled water, and 50 g of 3-aminopropylmethoxysilane was added thereto, followed by standing at room temperature for 6 hours. Thereafter, about 200 g of silicon fine sludge was recovered by filtration and washing using a centrifuge. The silicon sludge was introduced into a spin flash dryer at a temperature of 160 ° C. and recovered as a white silicon powder. The silicon fine particles thus recovered were subjected to a surface treatment through a second drying process in a kiln rotary dryer at 300 ° C. for 2 hours to give a controlled hydroxyl group to the surface of the powder particles. As a result, silicon fine particles having an OH index 0.71 value were obtained.

Comparative Example 1

420 g of methyltrimethoxysilane was dispersed in 2580 ml of distilled water and stirred for 1 hour. Then, the pH was adjusted to 10 by adding ammonia water, restirring for 1 hour, and the silicone latex was synthesized by standing for 2 hours at room temperature. The latex thus synthesized was recovered to about 200 g of white particulate sludge through a filtration and washing process using a centrifuge. The polymethoxysilsesquioxane sludge was recovered in the form of white silicon powder through a primary drying process using a spin flash dryer under the condition of a temperature of 200 ° C.

Comparative Example 2

420 g of methyltrimethoxysilane was dispersed in 2580 ml of distilled water and stirred for 1 hour. Then, the pH was adjusted to 10 by adding ammonia water, restirring for 1 hour, and the silicone latex was synthesized by standing for 2 hours at room temperature. The latex thus synthesized was recovered to about 200 g of white particulate sludge through a filtration and washing process using a centrifuge. The sludge was dried in a vacuum dryer at 600 ° C. for 2 hours, and as a result, polyorganosilsesquioxane fine particles having an OH index 0.60 value were obtained.

In each of the Examples and Comparative Examples, the surface-treated hydroxyl groups were quantitatively compared by changing the conditions of temperature and time, and the respective silicon beads were prepared according to the particle surface OH index value. In order to prepare the synthesized silicon beads in a master batch to be used for diffusion plate injection, silicon beads, polystyrene resin, and EXL-5136 (Rohm & Hass, USA) were prepared and used at a ratio of 1: 100: 1, and Φ = 45 mm. Pellets were prepared by mixing using a twin screw extruder. After that, a plate specimen (simple diffuser plate) having a thickness of 1.5 mm was prepared at a molding temperature of 210 ° C. in a 10 oz injection machine, and the luminance was evaluated using the prepared plate specimens to determine the optimal amount of hydroxyl group, that is, the OH index. Could find. Table 1 summarizes the OH index values and luminance calculated by the relational formula 1 through the IR analysis of the silicon particles subjected to the drying and surface treatment process in each of the above Examples and Comparative Examples.

The fine particles obtained through the above process were evaluated for physical properties through the following methods, the evaluation results are shown in Table 1 below.

(1) OH index value analysis: OH index value according to the above formula was analyzed by particle surface IR analysis to compare the amount of hydroxyl groups on the particle surface.

(2) Luminance: Five diffusion plate specimens prepared by the above injection molding were taken and measured from 1 to 5 consecutively using a portable luminance meter (Luminometer NL-1, Nippon, Japan). This overall measurement was repeated three more times and the average value was taken and compared.

As shown in Table 1, it can be seen that the luminance decreases as the hydroxyl group decreases, and thus the concentration of the appropriate hydroxyl group, that is, the OH index value, is required, rather than unconditionally introducing a large number of hydroxyl groups.

When there is a large amount of hydroxyl groups on the surface as in Comparative Example 1, i.e., when x has a large amount of adsorption, the affinity with water increases, so that compatibility with the resin is reduced, and workability such as water vapor generation during extrusion is significantly reduced and diffused. Difficulty in ejecting the plate makes it impossible to obtain the specimen.

Therefore, as can be seen from Table 1, Examples 1 to 4 having an OH index value ranging from 0.7 to 1.0 exhibited optimum luminance.

The present invention provides a silicon fine particles having excellent brightness and light resistance, improved compatibility with a resin and workability by providing a hydroxyl group having a constant concentration on the surface of the particle through a surface treatment operation, a method of manufacturing the same, and a light diffusion plate using the same. Has an effect.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (13)

Silicon fine particles characterized in that the surface treatment so that the OH index value according to the formula below ranges from 0.7 to 1.0: OH index = [Abs. (At 3350-3400-3450 cm ^-1 )] / [Abs. (At 2920-2970-3020 cm ^-1 )] [Abs. (At 3350-3400-3450 cm ^-1 )]: Si-OH peak [Abs. (At 2920-2970-3020 cm ^-1 )]: Si-CH ₃ peak. According to claim 1, wherein the silicon microparticles are silicon microparticles, characterized in that having a repeating unit represented by the formula (1): [Formula 1] RSiO _1.5-x (OH) _x R represents an alkyl group having 1 to 6 carbon atoms, a vinyl group, an aryl group, and an alkyl substituted aryl group, wherein 0 <x <1.5. The silicon fine particle according to claim 2, wherein R is a methyl group. The silicon fine particle according to claim 1, wherein the silicon fine particle has an average particle diameter of 0.1 to 20 m. Surface treatment of the powder-type polyorgano silsesquioxane particles, the method for producing silicon fine particles, characterized in that the hydroxyl group concentration on the surface of the particle is adjusted so that the OH index value according to the following formula is in the range of 0.7 to 1.0: OH index = [Abs. (At 3350-3400-3450 cm ^-1 )] / [Abs. (At 2920-2970-3020 cm ^-1 )] [Abs. (At 3350-3400-3450 cm ^-1 )]: Si-OH peak [Abs. (At 2920-2970-3020 cm ^-1 )]: Si-CH ₃ peak. The method for producing silicon fine particles according to claim 5, wherein the surface treatment is heat-treated at 200 to 400 ° C. Drying the polyorganosilsesquioxane latex to prepare silicon fine particles in powder form; And Drying or sintering the silicon fine particles in powder form to adjust the hydroxyl concentration on the surface of the particle such that the OH index value is in the range of 0.7 to 1.0; Method for producing a silicon particulate, characterized in that consisting of steps: OH index = [Abs. (At 3350-3400-3450 cm ^-1 )] / [Abs. (At 2920-2970-3020 cm ^-1 )] [Abs. (At 3350-3400-3450 cm ^-1 )]: Si-OH peak [Abs. (At 2920-2970-3020 cm ^-1 )]: Si-CH ₃ peak. The method for producing silicon fine particles according to claim 7, wherein the polyorganosilsesquioxane latex is made of an organoalkoxy silane by a sol-gel process. The method for producing silicon fine particles according to claim 7, wherein the drying or sintering step is performed at 200 to 400 ° C for 30 minutes to 3 hours. A light diffusion plate using the silicon fine particles of claim 1 as a diffusing agent. The light diffusing plate of claim 10, wherein the light diffusing plate comprises 0.1 to 10 parts by weight of the silicon fine particles with respect to 100 parts by weight of the thermoplastic resin. The method of claim 11, wherein the thermoplastic resin is a group consisting of vinyl chloride resin, styrene resin, styrene-acrylonitrile resin, acrylic resin, acrylic-styrene resin, ester resin, ABS resin, and polycarbonate resin. Light diffusion plate, characterized in that selected from. The light diffusion plate of claim 10, wherein the light diffusion plate is a diffusion plate for LCD-TV.