KR20090039475A - Process for preparing embossed monodisperse spherical light diffuser - Google Patents

Abstract

A method for manufacturing an embossed monodisperse light diffuser is provided to simplify the polymerization process and reduce the manufacturing cost by realizing the particle diameter of 1 to 30 micrometers through only one swelling process. In a dispersion medium which is the mixed co-solvent of the organic solvent and water, by performing the soap-free emulsion polymerization for the vinyl aromatic monomer and polymerization initiator, a seed particle is formed. By adding the seed particle after mixing the monomer, polymerization initiator and dispersion stabilizer, the soap-free emulsion polymerization for an embossed monodisperse light diffuser can be performed through only one swelling process.

Description

Process for Preparing Embossed Monodisperse Spherical Light Diffuser

The present invention relates to a method for producing an uneven type monodisperse light diffusing agent that is polymerized in a single absorption process after preparing large diameter aromatic vinyl seed particles by emulsion-free polymerization.

Polymeric particles are generally polymerized using heterogeneous phase polymerization. Representative polymerization methods include emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, and seed polymerization. Spherical polymer resin particles having a size of several μm polymerized by a heterogeneous polymerization method are processed into a resin through post-treatment such as washing and drying, or used as such. The monodisperse resin particles prepared as described above are light diffusing agents, which are materials of liquid crystal display devices and light diffusing films, standard materials used to test equipment, packing materials for chromatography columns, porous particles, uneven particles, and coloring. It is applied to particles and the like. In addition, it is applied to various fields of high value added such as measuring the size and efficiency of filter pores, support in biochemistry, biomedical field, coating, ink, copy toner, information industry and microelectronic devices.

The light diffusing film is used to allow the line light source irradiated from the light source to more uniformly diffuse through the light guide plate. Attempts have been made to improve the brightness of liquid crystal displays using improved light diffusing films. However, there is a limitation in improving the brightness. Therefore, a method of improving the brightness by adjusting the average particle diameter and the coefficient of variation coefficient (CV) of the improved resin particles is attempted. It is becoming. In addition, a method of adjusting the refractive index by changing the monomer of the light diffusing agent or improving the brightness by using particles containing pores has been attempted.

There are several methods for producing the light-diffusion resin particles, including suspension polymerization, dispersion polymerization, and emulsion-free polymerization, and seed polymerization for polymerization using seeds.

Suspension Polymerization is a method in which droplets are polymerized by mechanical mixing using a vinyl monomer, a polymerization initiator, a suspending agent and water as components of a polymerization reaction. Although it is possible to produce polydisperse polymer particles of several tens of micrometers in size, it is not suitable to make monodisperse polymer resin particles.

Dispersion Polymerization is a vinyl monomer, a polymerization initiator, a steric stabilizer, which is a high molecular material, and an organic solvent as components of the polymerization reaction. As the polymerization proceeds, polymers having increased molecular weight do not dissolve in the organic solvent and precipitate. In this case, the precipitated polymer refers to a polymerization method of forming spherical particles in the size of several hundred nm to several tens of micrometers by the steric stabilizer.

Soap Free Emulsion Polymerization is the polymerization of vinyl monomer, water-soluble polymerization initiator, water and organic solvent with reaction medium.In the initial stage of reaction, oligomer reacted with water-soluble polymerization initiator forms micelles. It becomes a nucleus, the reaction proceeds by the emulsion polymerization mechanism, and after the middle of the reaction refers to a polymerization method in which the particles are swollen by an organic solvent and spherical particles are obtained in the size of several hundred nm to several tens of m.

Seeded Polymerization is an efficient method for producing monodisperse polymer particles having a uniform size of 1 to 50 μm that are difficult to prepare by emulsion polymerization, dispersion polymerization and suspension polymerization. In general, two kinds of seed polymerizations have been proposed, and one of them is a method using a two-stage swelling process developed by J. Ugelstad. This method is a step of swelling seed particles primarily by oligomers or organic solvents and then swelling by monomers. Another method is to use a dynamic swelling process developed by M. Okubo, which disperses seed particles in an organic solvent in which monomers, dispersion stabilizers, and reaction initiators are dissolved, and then slowly It is a method of lowering the solubility of a monomer by adding so that monomer may adsorb | suck to a seed.

The particle size variation coefficient (CV) of a polymer particle is a value which takes a photograph by an electron microscope, and measures with respect to arbitrary 250 particle | grains of this image using an image analyzer, and calculates it according to following Formula.

Coefficient of variation (CV) = standard deviation of particle size (σ) / particle size (Dn)

Standard Deviation of Particle Size (σ) = (Di-Dn) / (n-1) x Dn

Di = particle diameter of each particle, n = 250

The light diffusing particles can be divided into uneven and porous types according to the production method. Japanese Patent Laid-Open No. 2006-2451226 introduces a method for producing porous monodisperse particles. This method is a porous layer made by expanding 20 ~ 80 times with monomer and initiator mixture expansion liquid containing 70% or more of methyl methacrylate and 3 ~ 8% by mass of divinyl benzene with seed particles of 70% or more of acrylic resin mass. Dispersed particles. The produced particles introduce a micron sized porous, porous, narrow particle size, monodisperse method. In this method, seed polymerization was carried out four times, resulting in poor productivity and poor solvent resistance of particles produced using divinylbenzene. Japanese Patent Laid-Open No. 2005-336223 introduces a method of preparing seed particles by dispersion polymerization, synthesizing a polymer resin containing a functional group, and then mixing the seed particles and the polymer resin to form uneven particles. However, the particles produced by this method have a poor solvent resistance and are different from the particle-shaped production method using phase separation. In Japanese Patent Laid-Open No. 2006-143968, the first step is to prepare seed particles by non-emulsion polymerization, and the second step is to introduce a method of preparing uneven polymer particles by directly adding a crosslinking monomer by secondary emulsion-free polymerization. have. However, this method also has poor solvent resistance of the produced particles and the particle diameter does not exceed 1 micron. Japanese Patent Laid-Open No. 2003-226708 introduces a method for producing heteroparticles in which the seed particles are polymerized by dispersing but the polymerized seed particles are not uneven.

 Conventionally, when the porous crosslinked resin particles are molded into a light diffusing film and a light diffusing plate, the light diffusing property is excellent, but the solvent resistance is weak, so that a defect appears. Therefore, the present inventors have developed a large diameter cross-linked seed using an emulsion-free polymerization method, and then polymerized through a single swelling process to develop a method for preparing an uneven monodisperse light diffusing agent having a size of 1 to 30 μm. .

An object of the present invention is to prepare a concave-convex monodisperse light diffuser in order to overcome the problems of a porous light-diffusing agent, the concave-convex monodisperse light diffuser is dispersed in toluene at room temperature and measured after 72 hours, the viscosity is 30Cp or less It has excellent solvent resistance, has a size of 1 ~ 30㎛ with only one swelling, has a particle size coefficient (CV) of 10% or less, and has an uneven type with a surface area of 0.1 m ² / g to 500 m ² / g It is to provide a method for producing a monodisperse light diffusing agent.

The present invention to achieve the above object

a) forming seed particles by emulsion-free polymerization of an aromatic vinyl monomer and a polymerization initiator in a dispersion medium which is a mixed cosolvent of water and an organic solvent; And

b) emulsion-free polymerization of the uneven monodisperse light diffusing agent in one swelling process by adding the seed particles of step a) after mixing the monomer, the polymerization initiator, and the dispersion stabilizer;

It provides a method for producing an uneven type monodisperse light diffusing agent comprising a.

In the present invention, the aromatic vinyl monomer of step a) is selected from styrene, divinylbenzene, ethylvinylbenzene, alphamethylstyrene, fluororostyrene and vinyl pyridine or mixtures thereof, and is easy to form seed particles. It is good to manufacture seed particle | grains using a styrene monomer, and the copolymerization monomer which is an aromatic vinyl monomer copolymerizable with the said styrene monomer may copolymerize in the range which does not impair the characteristic of a seed particle. The copolymer monomer is a copolymer monomer selected from divinylbenzene, ethylvinylbenzene, alphamethylstyrene, fluororostyrene and vinyl pyridine or mixtures thereof. The reason for using the copolymerized monomer is to control the physical properties and molecular weight of the seed particles, the content of the copolymerized monomer is preferably used 0.001 ~ 0.5 parts by weight of copolymerization monomer with respect to 100 parts by weight of styrene monomer. If the content of the copolymerized monomer is more than 0.5 parts by weight based on 100 parts by weight of the styrene monomer, uneven particles are not produced. If the content of the copolymerized monomer is 0.001 parts by weight or less, it is difficult to expect the effect of using the copolymerized monomer. In particular, in order to form suitable seed particles, it is better to use 0.001 to 0.2 parts by weight based on 100 parts by weight of the styrene monomer.

In the present invention, the seed particles may be prepared by various methods such as non-emulsification polymerization, suspension polymerization, emulsion polymerization, and dispersion polymerization, but in the present invention, it is preferable to prepare the seed particles by modified oil-free polymerization.

In the present invention, the dispersion medium of step a) is not particularly limited, and it is possible to use a conventionally known solvent used for precipitation polymerization, and it is particularly preferable to use a mixed cosolvent of water and an organic solvent.

 It is preferable that the organic solvent is one in which the polymerizable monomer is dissolved but the resulting polymer is not dissolved. Although such a solvent can be appropriately selected according to the polymerizable monomer, for example, alcohols such as methanol, ethanol, propanol and butanol, cellosolves such as methyl cellosolve and ethyl cellosolve, acetone and methylethyl It is preferable to use ketones such as ketones and methylbutyl methyl, and organic solvents such as benzene, toluene, xylene, acetonitrile, N, N-dimethylformamide and dimethyl sulfoxide or mixed solvents thereof.

The dispersion medium of step a) used in the present invention is generally used in an amount of 500 to 2000 parts by weight based on 100 parts by weight of the aromatic vinyl monomer. If the dispersion medium is less than 500 parts by weight based on 100 parts by weight of the aromatic vinyl monomer, the progress of the polymerization reaction may not be smooth. In particular, in order to prepare seed particles having a desired particle size, it is more effective to use the amount of 1000 to 1500 parts by weight based on 100 parts by weight of the aromatic vinyl monomer.

In the step a) of the present invention, a polymerization initiator is used when preparing a suspension containing seed particles by emulsion-free polymerization. The polymerization initiators include potassium persulfate, ammonium persulfate, sodium persulfate, sodium bisulfate, 1,1-azobis (1-methylbutyronitrile-3-sodiumsulfonate), and 4,4-azobis (4 -Cyanovaleric acid) or mixtures thereof. The polymerization initiator is preferably used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the aromatic vinyl monomer. If the amount of the polymerization initiator is less than 0.01 parts by weight based on 100 parts by weight of the aromatic vinyl monomer, the rate of polymerization is significantly reduced. If it is more than 10 parts by weight, gelation may occur due to auto-acceleration. .

It is preferable that the seed particles formed in step a) of the present invention have a spherical shape, and have a particle diameter of 0.1 to 20 µm, preferably 1.2 to 6 µm. If the particle diameter of the seed particles is less than 0.1μm, irregularities do not occur. If the particle size exceeds 20μm, the seed particles do not have a spherical shape. The particle size variation coefficient (CV) of the seed particles is preferably 10% or less. When the particle size variation coefficient (CV) of the seed particles exceeds 10%, a light diffusing agent having a uniform particle size cannot be obtained, resulting in a decrease in luminance in the light diffusing film. Although the average molecular weight of a seed is not specifically limited, 100,000-300,000 are preferable, and 150,000-250,000 are especially preferable. If the average molecular weight is less than 100,000 phase separation does not occur, the irregularities of the particles do not occur, if more than 300,000 does not have a spherical particle form.

Step b) of the uneven type monodisperse light diffusing agent manufacturing method according to the present invention is a monomer, polymerization initiator, dispersion stabilizer mixed with an aqueous medium and then seed particles are added to the uneven type monodisperse light diffusion in one swelling and polymerization process Prepare the agent.

The monomer of step b) is used by mixing 3 to 50 parts by weight of styrene, 3 to 50 parts by weight of ethylene glycol dimethacrylate, and 1 to 70 parts by weight of acryl monomer with respect to 100 parts by weight of the total monomer, and more effective uneven type In order to prepare a monodisperse light diffusing agent, it is preferable to use a mixture of 3 to 40 parts by weight of styrene, 3 to 40 parts by weight of ethylene glycol dimethacrylate, and 1 to 70 parts by weight of an acrylic monomer based on 100 parts by weight of the total monomers. Do. If the styrene monomer is less than 3 parts by weight based on 100 parts by weight of the total monomers, surface irregularities do not occur. If the styrene monomer is more than 50 parts by weight, the surface irregularities are irregular. If the ethylene glycol dimethacrylate monomer is less than 3 parts by weight based on 100 parts by weight of the total monomers, surface irregularities do not occur. If the ethylene glycol dimethacrylate monomer is more than 50 parts by weight, irregularities on the surface are irregular. Acryl monomers are monofunctional acrylic monomers, and examples thereof include butyl methacrylate, 2-ethylhexylethyl methacrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate. A methacrylate type compound is used. If the acrylic monomers to be mixed are more than 70 parts by weight with respect to 100 parts by weight of the total monomers, uneven type monodisperse particles are not obtained. If it is less than 1 part by weight, surface irregularities are somewhat inferior.

The polymerization initiator used in step b) of the preparation method is acetylcyclohexylsulfonylperoxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, benzoyl peroxide, 2,2-azo, which is an oil-soluble polymerization initiator. Bisisobutyronitrile, azobis-2,4, -dimethylvaleronitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), di-isopropylperoxydicarbonate, di-2-ethyl Peroxides and nitrogen compounds selected from hexyl peroxy thicarbonate, dioctoxy ethyl peroxy dicarbonate, t-butyl pioxy neodecanate, and t-butyl peroxy neocatenate or mixtures thereof are used. This polymerization initiator is usually used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the monomer. If the amount of the polymerization initiator is less than 0.01 parts by weight based on 100 parts by weight of monomer, the rate of polymerization is significantly reduced, and if it exceeds 10 parts by weight, gelation occurs due to auto-acceleration.

Examples of the dispersion stabilizer used in step b) of the production method are selected from polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, copolymers thereof, or mixtures thereof. The dispersion stabilizer is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the monomer. If the dispersion stabilizer is less than 0.1 part by weight with respect to 100 parts by weight of the monomer, the effect of the dispersion stabilizer cannot be expected. If the dispersion stabilizer exceeds 10 parts by weight, the dispersibility is too enlarged to obtain an uneven monodisperse light diffusing agent having a desired particle size.

In step b) of the production method according to the invention the monomer is absorbed in the seed particles and then polymerized. In the present invention, the uneven monodisperse light diffusing agent is polymerized in step b) so as to be 2 to 200 times the weight of the seed particles obtained in step a). As such, in order to grow the seed particles, it is common to perform the polymerization process at least twice in the step b), but in the present invention, only one pass is performed.

 In step b), the monomer is used in an amount of 10 to 120 parts by weight, preferably 20 to 100 parts by weight, based on 1 part by weight of the seed particles. If the monomer is less than 10 parts by weight with respect to 1 part by weight of the seed particles, the particle size of the uneven type monodisperse light diffusing agent is not polymerized to a sufficient size, and if it is 120 parts by weight or more, a spherical uneven type monodisperse light diffuser is not obtained.

In the swelling process of step b), the swelling solution including the monomer, the polymerization initiator, and the dispersion stabilizer is absorbed at 10 to 120 parts by weight based on 1 part by weight of the seed particles and polymerized, preferably 20 to 100 parts by weight is absorbed. And polymerize.

The reaction temperature in step b) is 60 ° C ~ 80 ° C, the reaction time is carried out under the conditions of 3 to 24 hours.

The uneven type monodisperse light diffusing agent obtained by the manufacturing method according to the present invention has an average particle diameter in the range of 1 to 30 µm, and the coefficient of variation (CV) is usually 10% or less. The uneven type monodisperse light diffusing agent obtained in the present invention was observed with an electron microscope, and as a result, it was an uneven type and monodisperse sphere. Moreover, since it is a crosslinked fine particle, it does not melt | dissolve in organic solvents, such as toluene, ethyl acetate, a phenol, dichloroethane, acetone. However, the uneven type monodisperse light diffusing agent obtained by the production method according to the present invention is dispersed in toluene, and swelled at room temperature for 72 hours to have a viscosity of 30 cP or less, which has very good solvent resistance. If the viscosity is 30 cP or more, the defect rate increases when used in a light diffusing film or the like.

The uneven monodisperse light diffusing agent has a surface area of 0.1 m ² / g to 500 m ² / g. If the surface area is 0.1 m ² / g or less, the particle size increases, and the size of the irregularities generated on the surface increases when the film is used.If the surface area is more than 500 m ² / g, the size of the particles decreases. Difficult to do

As described in detail above, the uneven type monodisperse light diffusing agent obtained by the manufacturing method according to the present invention has a particle diameter of 1 to 30 μm with a single swelling, thereby simplifying the polymerization process and lowering the production cost, and the coefficient of variation Since (CV) is 10% or less, light diffusing plate or film can have uniform light diffusing property by using light diffusing agent of uniform particle size, and because of excellent solvent resistance, defect rate in manufacturing light diffusing plate or film There is an effect that can be lowered.

Hereinafter, the present invention will be described in more detail with reference to Preparation Examples, Examples, and Comparative Examples, but the following Preparation Examples, Examples, and Comparative Examples do not limit the spirit and scope of the present invention.

In the preparation examples, examples and comparative examples of the present invention, the average particle diameter and the coefficient of variation of the particle size were measured using a Multimannizer Coulter Counter of Beckmann Coulter, and the viscosity was measured using a LVDV-E230 from Brookfield. The surface area was measured using a MicroMeritics ASAP2420 model.

Preparation Example 1 Preparation of Seed Particle A Dispersion

150 g of distilled water, 250 g of 2-methoxyethanol, 40 g of styrene, 0.001 g of ethylvinylbenzene, and 0.4 g of potassium perperate were placed in a 5 L reactor, maintained in a nitrogen atmosphere, heated to 70 ° C., and polymerized at 100 rpm for 6 hours. Seed Particle A dispersion was prepared. As a result of analyzing the prepared seed particle A dispersion, the average particle diameter of the seed particle A was 1.35 µm, the coefficient of variation (CV) was 3.8%, and the weight average molecular weight (M _w ) was 220,000.

Preparation Example 2 Preparation of Seed Particle B Dispersion

120 g of distilled water, 280 g of 2-methoxyethanol, 40 g of styrene, 0.004 g of divinylbenzene, and 0.4 g of potassium perperate were placed in a 5 L reactor, maintained in a nitrogen atmosphere, heated to 70 ° C., and polymerized at 100 rpm for 6 hours. Seed B dispersion was prepared. As a result of analyzing the prepared seed particle B dispersion, the average particle diameter of the seed particle B was 2.71 µm, the coefficient of variation (CV) was 4.1%, and the weight average molecular weight (M _w ) was 210,000.

Preparation Example 3 Preparation of Seed Particle C Dispersion

100 g of distilled water, 300 g of 2-methoxyethanol, 40 g of styrene, and 0.4 g of potassium perperate were placed in a 5 L reactor, maintained in a nitrogen atmosphere, heated to 70 ° C., and polymerized at 100 rpm for 6 hours to obtain seed particle C dispersion. Prepared. As a result of analyzing the prepared seed particle C dispersion, the average particle diameter of the seed particle C was 4.07 µm, the coefficient of variation (CV) was 5.8%, and the weight average molecular weight (M _w ) was 200,000.

Preparation Example 4 Preparation of Seed Particle D Dispersion

70 g of distilled water, 330 g of 2-methoxyethanol, 40 g of styrene, and 0.4 g of potassium perperate were placed in a 5 L reactor, maintained in a nitrogen atmosphere, heated to 70 ° C., and polymerized at 100 rpm for 6 hours to obtain seed particle D dispersion. Prepared. As a result of analyzing the prepared seed particle D dispersion, the average particle diameter of the seed particle D was 5.43 µm, the coefficient of variation (CV) was 8.8%, and the weight average molecular weight (M _w ) was 190,000.

Example 1 Preparation of Uneven Type Monodisperse Light Diffusion Agent 1

5 g of styrene, 65 g of methyl methacrylate, 30 g of ethylene glycol dimethacrylate and 0.1 g of benzoyl peroxide were added to the same apparatus as in Preparation Example 1, and 300 g of distilled water containing 0.1 g of polyvinyl alcohol was added thereto. Mix for a minute. Subsequently, 22 g of the seed particle A dispersion liquid obtained in Production Example 1 was added to the mixed solution and swollen at room temperature for 1 hour, and then reacted at 70 ° C. for 6 hours to obtain a dispersion of uneven monodisperse light diffusing agent 1.

As a result of observing the obtained uneven monodisperse light diffusing agent 1 with an electron microscope, the shape of the particles was uneven, the average particle diameter was 5.01 µm, and the coefficient of variation (CV) was 6.2%. The uneven monodisperse light diffusing agent 1 was washed with distilled water and dried to obtain 70 g of the uneven monodisperse light diffusing agent 1 in powder form. 50 g of the powdery uneven monodisperse light diffusing agent 1 and 50 g of toluene were mixed and swollen at room temperature for 72 hours to measure the viscosity thereof. As a result, a 12cP value was obtained. The surface area was 1.1 m ² / g.

Example 2 Preparation of Uneven Type Monodisperse Light Diffusion Agent 2

Into the same device as Preparation Example 1, 5g of styrene, 65g of methyl methacrylate, 30g of ethylene glycol dimethacrylate and 0.1g of benzoyl peroxide were added thereto, and 300g of distilled water in which 0.1g of polyvinyl alcohol was dissolved was stirred. Under mixing for 10 minutes. Subsequently, 22 g of the seed particle B dispersion obtained in Preparation Example 2 was added to the mixed solution and swollen at room temperature for 1 hour, and then reacted at 70 ° C for 6 hours to obtain a dispersion of uneven monodisperse light diffusing agent 2.

As a result of observing the obtained uneven type monodisperse light diffusing agent 2 with an electron microscope, the shape of the particles was uneven, the average particle diameter was 10.1 µm, and the coefficient of variation (CV) was 8.2%. The concave-convex monodisperse light diffusing agent 2 was washed with distilled water and dried to obtain 70 g of the concave-convex monodisperse light diffusing agent 2 in powder form. 50 g of powdery uneven monodisperse light diffusing agent 2 and 50 g of toluene were mixed and swollen at room temperature for 72 hours, and the viscosity thereof was measured. As a result, a 12cP value was obtained. The surface area was 1.8 m ² / g.

Example 3 Preparation of Uneven Type Monodisperse Light Diffusion Agent 4

Into the same device as in Preparation Example 1, 10 g of styrene, 60 g of methyl methacrylate, 30 g of ethylene glycol dimethacrylate, and 0.1 g of benzoyl peroxide were added thereto, and 300 g of distilled water containing 0.1 g of polyvinyl alcohol was added thereto. Under mixing for 10 minutes. Subsequently, 22 g of the seed particle C dispersion obtained in Preparation Example 3 was added to the mixed solution and swollen at room temperature for 1 hour, and then reacted at 70 ° C. for 6 hours to obtain a dispersion of uneven monodisperse light diffusing agent 3.

As a result of observing the obtained uneven monodisperse light diffusing agent 3 with an electron microscope, the shape of the particles was uneven, the average particle diameter was 15.2 µm, and the coefficient of variation (CV) was 7.7%. The uneven monodisperse light diffusing agent 3 was washed with distilled water and dried to obtain 70 g of the uneven monodisperse light diffusing agent 3 in powder form. 50 g of the powdery uneven monodisperse light diffusing agent 3 and 50 g of toluene were mixed and swollen at room temperature for 72 hours, and the viscosity thereof was measured. As a result, a value of 6cP was obtained. The surface area was 1.2 m ² / g.

Example 4 Preparation of Uneven Type Monodisperse Light Diffusion Agent 4

Into the same device as in Preparation Example 1, 10 g of styrene, 60 g of methyl methacrylate, 30 g of ethylene glycol dimethacrylate, and 0.1 g of benzoyl peroxide were added thereto, and 300 g of distilled water containing 0.1 g of polyvinyl alcohol was added thereto. Under mixing for 10 minutes. Subsequently, 22 g of the seed particle B dispersion obtained in Preparation Example 2 was added to the mixed solution and swollen at room temperature for 1 hour, and then reacted at 70 ° C for 6 hours to obtain a dispersion of uneven monodisperse light diffusing agent 4.

As a result of observing the obtained uneven | corrugated monodisperse light-diffusing agent 4 with the electron microscope, the shape of particle | grains was uneven | corrugated form, the average particle diameter was 20.5 micrometers, and the coefficient of variation (CV) was 9.1%. The uneven monodisperse light diffuser 4 was washed with distilled water and dried to obtain 70 g of the uneven monodisperse light diffuser 4 in powder form. 50 g of the powdery uneven monodisperse light diffusing agent 4 and 50 g of toluene were mixed, swollen at room temperature for 72 hours, and the viscosity thereof was measured. As a result, a value of 6cP was obtained. The surface area was 1.1 m ² / g.

Comparative Example 1 Preparation of Comparative Light Diffusion A

150 g of distilled water, 250 g of 2-methoxyethanol, 40 g of styrene, and 0.4 g of potassium perperate were placed in a 5 L reactor, maintained in a nitrogen atmosphere, heated to 70 ° C., and polymerized at 100 rpm for 6 hours to prepare seed particles. . As a result of sampling and analyzing a small amount of the seed particles, the average particle diameter of the seed particles was 1.35 µm, the coefficient of variation (CV) was 3.8%, and the weight average molecular weight (M _w ) was 220,000.

Into the same apparatus as above, 6 g of divinylbenzene, 94 g of methyl methacrylate, and 0.1 g of benzoyl peroxide were added thereto, 300 g of distilled water containing 0.1 g of polyvinyl alcohol was added thereto, followed by mixing for 10 minutes under stirring. Subsequently, 22 g of the seed particle dispersion prepared in the above-described seed particle manufacturing process was added to the mixture, and the mixture was swollen at room temperature for 1 hour, and then reacted at 70 ° C for 6 hours to obtain a dispersion of comparative light diffusing agent A.

As a result of observing the obtained comparative light diffusing agent A with an electron microscope, the shape of the particles was uneven, the average particle diameter was 10.1 µm, and the coefficient of variation (CV) was 3.1%. The comparative light diffusing agent A was washed with distilled water and dried to obtain a powder. 50g of powder comparative light diffusing agent A and 50g of toluene were mixed and completely swollen after 72 hours at room temperature, thereby making it impossible to measure viscosity. The surface area was 3.3 m ² / g.

Comparative Example 2 Preparation of Comparative Light Diffusion Agent B

150 g of distilled water, 250 g of 2-methoxyethanol, 40 g of styrene, and 0.4 g of potassium perperate were placed in a 5 L reactor, maintained in a nitrogen atmosphere, heated to 70 ° C., and polymerized at 100 rpm for 6 hours to prepare seed particles. . As a result of sampling and analyzing a small amount of the seed particles, the average particle diameter of the seed particles was 1.35 µm, the coefficient of variation (CV) was 3.8%, and the weight average molecular weight (M _w ) was 220,000.

Into the same apparatus as above, 15 g of divinylbenzene, 85 g of methyl methacrylate, and 0.1 g of benzoyl peroxide were added thereto, 300 g of distilled water containing 0.1 g of polyvinyl alcohol was added thereto, followed by mixing for 10 minutes under stirring. Subsequently, 22 g of the seed particle B dispersion prepared in the above-mentioned seed particle manufacturing process was added to the mixed solution and swollen at room temperature for 1 hour, and then reacted at 70 ° C. for 6 hours to obtain a dispersion of comparative light diffusing agent B.

As a result of observing the obtained comparative light diffusing agent B with an electron microscope, no particles were formed.

Comparative Example 3 Preparation of Comparative Light Diffusion Agent C

100 g of methyl methacrylate, 1 g of potassium perperate, and 1 g of ethylene glycol dimethacrylate were added to 900 g of distilled water, heated to 70 ° C. while maintaining a nitrogen atmosphere, and polymerized for 6 hours while stirring at 100 rpm. Particles were prepared. As a result of sampling and analyzing a small amount of the seed particles, the size of the seed particles was 0.2 μm and the coefficient of variation (CV) was 8.8%.

To 100 g of the suspension was added 900 g of distilled water in which 1 g of sodium lauryl sulfate was dissolved, and a mixture of 100 g of methyl methacrylate in which 1 g of benzoyl peroxide and 1 g of ethylene glycol dimethacrylate was added, followed by swelling at room temperature for 6 hours under vigorous stirring. And polymerization was carried out at 70 ° C. for 6 hours to obtain a suspension.

The same seed synthesis was carried out five times in succession to obtain a suspension having an average particle diameter of 8.19 µm and a coefficient of variation (CV) of 11.8%.

To the same apparatus as above, add 100 g of the suspension to 900 g of distilled water in which 1 g of sodium lauryl sulfate was dissolved, add a mixture of 5 g of divinylbenzene in which 1 g of benzoyl peroxide and 95 g of methyl methacrylate were added, and then swell for 6 hours with vigorous stirring. After reacting at 70 ° C. for 6 hours, a dispersion of comparative light diffusing agent C was obtained.

As a result of observing the obtained comparative light diffusing agent C with an electron microscope, the shape of the particles was uneven, the average particle diameter was 12.9 µm, and the coefficient of variation (CV) was 11.6%. The comparative light diffusing agent C was washed with distilled water and dried to obtain a powder. 50 g of powder comparative light diffusing agent C and 50 g of toluene were mixed, swollen at room temperature for 72 hours, and the viscosity thereof was measured. The result was 4500 cP. The surface area was 2.3 m ² / g.

Table 1. Comparative Table of Examples and Comparative Examples

Concave-type monodisperse light diffusing agent according to the present invention can be used in the light diffusion film, light diffusion sheet, brightness enhancement of the light emitting diode, fluorescent lamp shade, cosmetics containers, nighttime billboards, etc. which are used in the existing industry and based on excellent solvent resistance By lowering the defective rate, the competitiveness of the entire production unit can be improved.

Figure 1 shows the results of observing the uneven type single injection light diffusing agent with an electron microscope.

Claims (23)

a) forming seed particles by emulsion-free polymerization of an aromatic vinyl monomer and a polymerization initiator in a dispersion medium which is a mixed cosolvent of water and an organic solvent; And b) emulsion-free polymerization of the uneven monodisperse light diffusing agent in one swelling process by adding the seed particles of step a) after mixing the monomer, the polymerization initiator, and the dispersion stabilizer; Method of producing a concave-convex monodisperse light diffusing agent comprising a. The method of claim 1, The aromatic vinyl monomer of step a) may be selected from styrene, divinylbenzene, ethylvinylbenzene, alphamethylstyrene, fluororostyrene and vinyl pyridine or mixtures thereof. Manufacturing method. The method of claim 2, The aromatic vinyl monomer is a method for producing an uneven type monodisperse light diffusing agent, characterized in that 0.001 to 0.5 parts by weight of styrene or 100 parts by weight of styrene is used. The method of claim 3, wherein The copolymer monomer is a divinyl benzene, ethyl vinyl benzene, alpha methyl styrene, fluoro styrene and vinyl pyridine or a mixture thereof. The method of claim 1, The organic solvent of the dispersion medium in step a) is methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, methyl butyl ketone, benzene, toluene, xylene, acetonitrile, N And N-dimethylformamide, and dimethyl sulfoxide or a mixed solvent thereof, wherein the uneven type monodisperse light diffusing agent is prepared. The method of claim 5, The dispersion medium is a manufacturing method of the uneven type monodisperse light diffusing agent, characterized in that used in 500 to 2000 parts by weight based on 100 parts by weight of the aromatic vinyl monomer. The method of claim 1, The polymerization initiator of step a) is potassium persulfate, ammonium persulfate, sodium persulfate, sodium bisulfate, 1,1-azobis (1-methylbutyronitrile-3-sodiumsulfonate), and 4,4- Azobis (4-cyano valeric acid) or a mixture thereof is a method for producing an uneven monodisperse light diffusing agent. The method of claim 7, wherein The polymerization initiator is a method for producing an uneven type monodisperse light diffusing agent, characterized in that it is used in 0.01 to 10 parts by weight based on 100 parts by weight of the aromatic vinyl monomer. The method of claim 1, The seed particles of step a) is a particle diameter of 0.1 to 20μm, particle size variation coefficient (CV) 10% or less, weight average molecular weight (Mw) of 100,000 to 300,000, characterized in that the manufacturing method of the uneven monodisperse light diffuser. The method of claim 1, The monomer of step b) is an uneven type, characterized in that 3 to 50 parts by weight of styrene, 3 to 50 parts by weight of ethylene glycol dimethacrylate, and 1 to 70 parts by weight of acryl monomer, based on 100 parts by weight of the total monomers. Method for producing a dispersed light diffusing agent. The method of claim 10, The acryl monomer is selected from butyl methacrylate, 2-ethylhexylethyl methacrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate or a mixture thereof. Method for producing uneven type monodisperse light diffusing agent. The method of claim 1, The polymerization initiator of step b) is acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, benzoyl peroxide, 2,2-azobisisobutyronitrile, azobis- 2,4, -dimethylvaleronitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), di-isopropylperoxydicarbonate, di-2-ethylhexylperoxythicarbonate, dioctoxyethylperox A method for producing an uneven type monodisperse light diffusing agent, characterized in that it is selected from cd carbonate, t-butyl pioxy neodecanate, and t-butyl peroxy neo-tecanate or mixtures thereof. The method of claim 12, The polymerization initiator is 0.1 to 10 parts by weight based on 100 parts by weight of the monomer, characterized in that the uneven monodisperse light diffusing agent manufacturing method. The method of claim 1, The dispersion stabilizer of step b) is polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, and copolymers thereof, or a mixture thereof. The method of claim 14, The dispersion stabilizer is 0.1 to 10 parts by weight based on 100 parts by weight of the monomer, characterized in that for producing a monodisperse light diffusing agent. The method of claim 1, The monomer of step b) is an uneven type monodisperse light diffusing agent, characterized in that it is used in 10 to 120 parts by weight based on 1 part by weight of the seed particles of step a). The method of claim 1, The swelling process of step b) is a concave-convex monodisperse light diffusing agent characterized in that the swelling liquid containing a monomer, a polymerization initiator, and a dispersion stabilizer is absorbed at 10 to 120 parts by weight based on 1 part by weight of the seed particles and polymerized. Manufacturing method. The method of claim 1, a) a seed particle preparing step of forming seed particles by an emulsion-free polymerization, from 1000 to 1500 parts by weight of a dispersion medium, 100 parts by weight of an aromatic vinyl monomer, and 0.01 to 10 parts by weight of a polymerization initiator; And b) 100 parts by weight of the monomer, 0.1 to 10 parts by weight of the polymerization initiator, and 0.1 to 10 parts by weight of the dispersion stabilizer are added, and then a dispersion including 1 to 5 parts by weight of the seed particles of step a) is added to the unevenness in one swelling process. Emulsifying and polymerizing a monodisperse light diffusing agent; Method of producing a concave-convex monodisperse light diffusing agent comprising a. An uneven type monodisperse light diffuser, characterized in that it is produced by the manufacturing method of any one of claims 1 to 18. The method of claim 19, The uneven type monodisperse light diffusing agent has an average particle diameter of 1 to 30μm. The method of claim 19, The uneven type monodisperse light diffuser is uneven type monodisperse light diffuser, characterized in that the particle size coefficient (CV) is 10% or less. The method of claim 19, The uneven monodisperse light diffusing agent is a uneven monodisperse light diffusing agent dispersed in toluene, and swelled at room temperature for 72 hours to measure a viscosity of 0.001 to 30 cP. The method of claim 19, The uneven type monodisperse light diffusing agent has a surface area of 0.1 to 500 m ² / g.

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