KR100996863B1 - Polymer particles which are improved off dust and increased liquid stability and manufacturing method thereof - Google Patents

Abstract

The present invention is obtained from at least one selected from an aromatic vinyl monomer, an acrylic acid or methacrylic acid alkyl ester monomer having 1 to 20 carbon atoms, and an acrylic acid or methacrylic acid fluoroalkyl ester monomer having 1 to 20 carbon atoms, and has an average particle diameter. It provides polymer particles having 5 to 20 μm and 50 to 500 nm fine protrusions formed on the surface, which reduces dust blowing, which can reduce worker's hazards and is coated on light diffusion film, protective film, transparent film for color ink, etc. In order to prepare a solution, no separation of layers occurs, so that a separate stirring or milling process can be omitted, thereby simplifying the process.

Description

Polymer particles which are improved off dust and increased liquid stability and manufacturing method             

1 is an electron micrograph (× 2,000) of the polymer particles obtained according to the present invention,

2 is an electron micrograph (× 4,000) of the polymer particles obtained according to the present invention.

3 is an electron micrograph (× 2,000) of a conventional polymer particle,

4 is an electron micrograph (× 4,000) of a conventional polymer particle,

FIG. 5 is a graph showing measurement results of dust blowing of polymer particles obtained according to Example 1 and Comparative Example 1. FIG.

The present invention relates to a polymer particle and a method for producing the same, which is free of dust and has increased stability in liquid preparation. The present invention relates to polymer particles used for cosmetics, liquid crystal display spacers, anisotropic conductive films, and conductive particles of anisotropic conductive adhesives, and a method of manufacturing the same.

The polymer particles collectively refer to spherical particles having a uniform size distribution produced by emulsion polymerization, suspension polymerization, or the like. Polymer particles are used in a wide variety of applications, not only for the light diffusion film, protective film and construction of liquid crystal monitors, but also widely used for coating transparent films for color ink. In addition, it is used for various uses such as toners, cosmetics, liquid crystal display spacers, anisotropic conductive films, and conductive particles of anisotropic conductive adhesives.

These polymer particles, unlike general purpose polymers with high device dependence and low added value, such as olefin petrochemical products, nylon, polyester, etc., are technology-intensive, low device dependency, and relatively small quantities of high-priced and high value-added products.

Polymer particles are generally manufactured by methods such as suspension polymerization, dispersion polymerization, and emulsion polymerization.

In suspension polymerization, polymer particles are prepared by dispersing monomers present in an aqueous solution by mechanical force. Polymer particles produced by this method have a particle size of at least 100 μm or more, and the particle distribution tends to be wide because the particles are dispersed by mechanical force. Therefore, a separate device is required to control the particle size and particle distribution. Related technologies include US Pat. Nos. 4,017,670, 4,071,670, 4,085,169, and 4,129,706, and the like, which introduces techniques for producing polystyrene polymer beads.

Dispersion polymerization is carried out in a water medium in which the monomer to be polymerized is dissolved, and the resulting polymer is not dissolved in the medium. In addition, because of the high agglomeration incidence in this production method, the degree of crosslinking of the polymer beads produced is less than 2%, and when the polymer beads having a particle size of 10 µm or larger are produced, the particle distribution is wide.

Emulsion polymerization is a method of producing polymer beads in an aqueous solution using a water-soluble initiator, an emulsifier, and a monomer. By the use of an emulsifier, the particle distribution is narrow, and polymer beads having a particle size of 1 µm or less are produced. As an example of the related technology, US Patent No. 4,522,953 discloses a technique for preparing porous polystyrene polymer beads by emulsion polymerization.

Thus, in order to apply the polymer particles usefully used in the industrial field to the product must undergo a process of processing or crude liquid, a lot of dust is generated at this time. The dust generated is very harmful to the operator and has a detrimental effect on the final product. In addition, the crude liquid containing the polymer particles made to coat the particles on the light diffusion film, the protective film, the transparent film for the color ink, etc., is poor in stability, so that the layer separation occurs within several minutes and aggregation occurs within several hours. This phenomenon requires constant stirring and milling during the process and complicates the process.

Accordingly, the present inventors have completed the present invention by discovering that fine projections are formed on the surface of the particles while satisfying these requirements while researching to develop polymer particles having low dust and excellent liquid stability. Was done.

Accordingly, an object of the present invention is to provide a polymer particle having a good stability of the liquid solution with low dust blowing by modifying the surface of the polymer particle.

In addition, an object of the present invention is to provide a method for producing a polymer particle that can form a fine projection by modifying the surface of the polymer particle.

The polymer particles of the present invention for achieving the above object is selected from an aromatic vinyl monomer, acrylic acid or methacrylic acid alkyl ester monomer having 1 to 20 carbon atoms and acrylic acid or methacrylic acid fluoroalkyl ester monomer having 1 to 20 carbon atoms It is obtained from at least 1 type, It is characterized by having an average particle diameter of 5-20 micrometers, and 50-500 nm fine protrusion formed in the surface.

The method for producing the polymer particles as described above may be one or more selected from an aromatic vinyl monomer, an acrylic acid or methacrylic acid alkyl ester monomer having 1 to 20 carbon atoms, and an acrylic acid or methacrylic acid fluoroalkyl ester monomer having 1 to 20 carbon atoms. Preparing a polymer particle latex from; And it characterized in that it comprises the step of drying by stirring the polymer particle latex at 60 to 80 ℃, -10 to -72 cmHg for 12 to 24 hours.

The present invention will be described in more detail as follows.

Electron micrographs of the polymer particles according to the present invention are shown in FIGS. 1 and 2.

Conventional polymer particles have a smooth surface (FIGS. 3 and 4), but the polymer particles according to the present invention have fine projections of several tens to hundreds of nm in size, specifically, 50-500 nm fine projections on the surface thereof.

If the size of the fine protrusions is smaller than 50 nm, it is difficult to obtain the effect of eliminating dust or improving the stability of the liquid solution. If the size of the fine protrusions is larger than 500 nm, it is as if the particles are agglomerated to obtain a uniform product when coating the crude liquid. Can't.

The polymer particle is applicable to the industrial field that the average particle diameter is 5-20 micrometers.

In the production of the polymer particles, at least one monomer selected from among an aromatic vinyl monomer, an acrylic acid or methacrylic acid alkyl ester monomer having 1 to 20 carbon atoms, and an acrylic acid or methacrylic acid fluoroalkyl ester monomer having 1 to 20 carbon atoms is used. It is not limited to this.

Using such a monomer, a crosslinking agent, a stabilizer, an initiator, ion-exchanged water, and the like, the polymer particle latex can be produced according to a conventional method.

The crosslinking agent, stabilizer, initiator, ion-exchanged water is not particularly limited, but examples of the crosslinking agent include 1,2-ethanediol diacrylate, 1,3-propanediol diacrylate, and 1,3-butanediol diacrylate. , 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, divinylbenzene, ethylene glycol diacrylate, propylene glycol diacrylate, butylene Recall diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, polybutylene glycol diacrylate, allyl diacrylate, 1,2-ethanediol dimethacrylate, 1 , 3-propanedioldimethacrylate, 1,3-butanedioldimethacrylate, 1,4-butanedioldimethacrylate, 1,5-pentanedioldimethacrylate, 1,6-hexanedioldimethacrylate Latex, ethylene Recall dimethacrylate, propylene glycol dimethacrylate, butylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polybutylene glycol dimethacrylate One or more selected from methacrylate, allyl methacrylate and diallyl maleate can be used. The amount of use is usually about 1 to 98% by weight in the total polymer particle composition.

Stabilizers include polyvinyl alcohol, polyvinylpyrrolidone, methyl cellulose, ethyl cellulose, sodium carboxy methyl cellulose, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, sodium polymethacrylate, gelatin, polyacrylamide and polyethylene Oxide and the like, and the amount of use thereof is usually about 0.2 to 10% by weight in the total polymer particle composition.

Examples of the initiator include benzoyl peroxide, azobisisobutyronitrile, azobismethylbutyronitrile, azobiscyclohexanecarbonitrile and the like, and the amount of the initiator is usually about 0.1 to 5.0% by weight in the total polymer particle composition.

The ion-exchanged water that can be used in the production of the polymer particles is pure water having a resistance value of 5 MΩ or more under a nitrogen stream generated through an ion exchanger, and can be usually used so as to be 100 to 500 parts by weight based on the total monomers.

The polymer particle latex is prepared from such ion-exchanged water, monomers, crosslinking agents, initiators, and stabilizers, and then generally dehydrated, washed, and dried. Generally, drying is performed under a vacuum oven.

However, in the present invention, the polymer particles satisfying the above conditions can be obtained as a result of changing the drying conditions at the time of drying.

Specifically, it is dried under vigorous stirring for 12 to 24 hours at a pressure condition of 60 to 80 ° C and -10 to -72 cmHg.

Stirring here is not limited to a particular speed and can be adjusted in consideration of the size of the stirrer.

This continuous friction on the polymer particles can produce small projections of tens to hundreds of nm on the surface of the particles, and these micro-projections do not slip between the particles, making them difficult to fly. It increases stability inside and prevents it from sinking.

Although the manufacturing process of the specific polymer particles is not limited, the first step may be divided into a step of preparing the polymer particle latex, and the second step of forming a fine protrusion on the surface of the polymer particles.

In the preparation of the polymer particle latex, the ion-exchanged water, the monomer, the crosslinking agent, the initiator, and the stabilizer are added to a reactor to prepare a premixing solution, and the solution is discharged from the reactor to prepare a stable particle forming solution through a homogenizer. After that, the mixture was put back into the reactor to raise the internal temperature to 60 to 90 ° C. to prepare polymer particles having a size of 5 to 20 μm.

Then, the obtained polymer particle latex is cooled to room temperature, dehydrated through centrifugation, washed repeatedly with ion-exchanged water four to five times, and then dried under the above-mentioned drying conditions to obtain the polymer particles of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Example 1

0.5 g of azobisisobutyronitrile was dissolved in a mixed solution of 350.4 g of methyl methacrylate, 30.4 g of ethyl acrylate, and 51.9 g of 1,6-hexanediol diacrylate, and then polyvinyl alcohol was dissolved in 1,000 g of secondary distilled water. 10g was added to the dissolved solution, which was added to a 3L reactor, and stirred at 700 rpm for 30 minutes at high speed to prepare a premixing solution. The prepared suspension was homogenized twice at a pressure of 4,000 psi and then charged into a 3L reactor and polymerized for 6 hours while gradually raising the temperature from 60 ° C to 90 ° C.

After the polymerization was completed, the suspension was filtered and washed three times with distilled water and dried under constant pressure at -72cmHg and a temperature of 70 ° C. for 24 hours, followed by continuous friction for 24 hours to prepare polymer particles. .

Comparative Example 1

To prepare a polymer particle in the same manner as in Example 1, but was dried for 24 hours at a temperature of 70 ℃ without performing agitation during drying.

Experimental Example

1 to 4 show the results of observing the surfaces of the particles obtained in Example 1 and Comparative Example 1 with an electron microscope (S4300, manufactured by Hitachi).

1 and 2 are electron micrographs of the polymer particles obtained according to Example 1, and it can be seen that fine protrusions are formed on the surface of the particles. Specifically, the size of the microprojections is about 50-500 nm. On the other hand, the polymer particles obtained according to Comparative Example 1 can be seen that the surface of the particles smooth as shown in FIG.

In addition, in order to evaluate the crude liquid stability of the particles obtained from Example 1 and Comparative Example 1, to form a crude liquid with a curing agent, a dispersant and a solvent, the polymer particles were stable after 0.5, 2, 6, 10, 14, 48, 72 hours. The results are shown in Table 1 below.

Neglect time after hours 0.5 2 6 10 14 48 72 Example 1 ○ ○ ○ ○ ○ ○ × Comparative Example 1 ○ × × × × × × ○: stability is maintained, x: stability is broken

From the results in Table 1, when the particles of Example 1 are used, the stability is maintained even after 48 hours, whereas when the particles of Comparative Example 1 are used, the stability is broken within 2 hours, and the particles are precipitated and solidified.

And, 10g, 20 minutes, 30 minutes, 40 minutes, 50 minutes and 60 minutes by stirring 10g each particle prepared in Example 1 and Comparative Example 1 at 100rpm in a 50ml beaker to determine the degree of dust Afterwards, the weight change of the particles remaining after blowing off to the dust was measured.

The results are shown in Fig.

From the results of FIG. 5, it can be seen that the particles obtained according to Example 1 were blown off by dust in 1.8 g within 60 minutes, whereas the particles obtained according to Comparative Example 1 were reduced by 1.5 g and 3.3 g compared to Example 1. Thus, it can be seen that the particles of Example 1 emit much less dust.

As described above in detail, according to the present invention, the polymer particles having the fine protrusions formed on the surface of the particles have less dust blowing, which can reduce the hazards of workers and coat them with a light diffusion film, a protective film, and a transparent film for color ink. In order to prepare the liquid, no separation of layers occurs, so that a separate agitation or milling process can be omitted, thereby simplifying the process.

Claims (3)

The polymer particle latex is obtained from at least one selected from an aromatic vinyl monomer, an acrylic acid or methacrylic acid alkyl ester monomer having 1 to 20 carbon atoms, and an acrylic acid or methacrylic acid fluoroalkyl ester monomer having 1 to 20 carbon atoms. A polymer particle having fine projections having an average particle diameter of 5 to 20 µm and an average particle diameter of 50 to 500 nm formed on the surface by stirring and drying the latex at 60 to 80 ° C. at -10 to -72 cmHg for 12 to 24 hours. Preparing a polymer particle latex from at least one selected from an aromatic vinyl monomer, an acrylic acid or methacrylic acid alkyl ester monomer having 1 to 20 carbon atoms and an acrylic acid or methacrylic acid fluoroalkyl ester monomer having 1 to 20 carbon atoms; And Method for producing a polymer particle comprising the step of drying by stirring the polymer particle latex at 60 to 80 ℃, -10 to -72 cmHg for 12 to 24 hours. The method for producing a polymer particle according to claim 2, wherein the polymer particles have an average particle diameter of 5 to 20 mu m and a fine protrusion having an average particle diameter of 50 to 500 nm formed on a surface thereof.

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