KR20030087812A - Manufacturing method of spherical polyamide fine-particles - Google Patents

Abstract

PURPOSE: Provided is a process for producing polyamide spherical fine particles used for a cosmetic filler, which can control average particle size and particle size distribution freely. CONSTITUTION: The process comprises the steps of: preparing a first solution containing a polyamide polymer and a second solution containing an emulsion-dispersing agent, wherein the polyamide polymer of the first solution is a nylon produced from a lactam or a non-nylon produced from an acid and a diamine; mixing the first solution and the second solution, and producing an emulsion from the mixture solution by stirring; evaporating a solvent from the emulsion to precipitate the polyamide spherical fine particles.

Description

Manufacturing method of spherical polyamide fine-particles

The present invention relates to a method for producing polyamide spherical fine particles, and more particularly, to a method for producing polyamide spherical fine particles that can control the average particle diameter and particle size distribution.

Polyamides that are commonly used have excellent properties such as strength, flexibility, hardness, elasticity, abrasion, possibility of washing, resistance to drying, mold, and damage. The present invention is mainly used for cosmetic fillers. It is to manufacture microparticles | fine-particles. Polyamide microparticles exhibit very high hydrophilicity compared to other polymer microparticles due to their polymer chemistry. However, the polyamide fine particles, which are mainly used as cosmetic fillers, are obtained mainly by precipitation through polymerization, and the resulting polyamide fine particles mostly exist in a porous amorphous form. Therefore, it has a disadvantage in that the sliding effect on the skin surface is inferior to spherical fine particles such as acrylic and silica, and thus has a limitation in texture.

In addition, when prepared by the conventional method has a disadvantage in that it is difficult to produce a fine powder having excellent monodispersity, it is difficult to control the particle shape and particle size distribution and the like of the desired spherical shape. For this reason, the development of polyamide spherical microparticles | fine-particles which are excellent in monodispersity but has a fine touch is urgently desired.

An object of the present invention is to provide a method for producing polyamide spherical fine particles which can freely control the average particle size and particle size distribution.

Another object of the present invention is to provide polyamide fine particles for cosmetic filler.

1 is a scanning electron microscope (SEM) photograph of polyamide spherical fine particles prepared according to the present invention.

2 is a scanning electron micrograph of another polyamide spherical microparticles prepared according to the present invention.

The production method of the present invention is a method for producing polyamide spherical fine particles from a polyamide polymer,

(a) a first step of preparing a first solution containing a polyamide polymer and a second solution containing an emulsion dispersant, respectively;

(b) a second step of preparing an emulsion from the mixed solution by mechanical high speed stirring by mixing the first solution and the second solution, and

and (c) a third step of depositing polyamide spherical fine particles by evaporating the solvent from the prepared emulsion.

Hereinafter, the present invention will be described in detail.

(1) First step

In the present invention, polyamide spherical fine particles are produced using a polyamide polymer as a raw material. Polyamides include both nylon-based and non-nylon-based materials prepared from dicarboxylic acids and diamines. First, using the polyamide polymer, the first solution containing the polyamide polymer and the emulsifying dispersant are first used as the first step. To prepare a second solution containing each. That is, in the present invention, the polyamide polymer / solvent and the emulsion dispersion solution are each prepared as separate solutions.

(a) First solution

The solvent used for the first solution is not particularly limited as long as the polyamide polymer is substantially dissolved therein and is not mixed with the second solution. For example, a solvent containing at least one of formic acid, concentrated sulfuric acid and concentrated nitric acid can be used.

The ratio of polyamide and solvent in the first solution may be appropriately set according to the type of polyamide used, the type of solvent, the concentration of the second solution, and the like. Usually, polyamide: solvent = 1: 3 to 1: 300. The weight ratio is preferably 1: 5 to 1:50. If the weight ratio of polyamide and solvent is 1: 3 or less, it is impossible to produce monodisperse fine particles with a high viscosity solution, and if it is 1: 300 or more, the production efficiency of the fine particles by the lean solution is undesirably lowered. .

(b) second solution

The emulsion dispersant-containing solution used as the second solution is not particularly limited. For example, a high molecular stereoscopic emulsion dispersant having high affinity with the solvent of the second solution, and low molecular electrostatic emulsification of anionic, cationic and nonionic systems. Dispersants can be used. These can use 1 type (s) or 2 or more types. Furthermore, in the present invention, a polysaccharide compound may be used in addition to the above-mentioned steric dispersant. The particle size distribution characteristic of the polyamide spherical microparticles | fine-particles obtained by these can be changed.

The solvent used in the second solution is not particularly limited as long as oils such as paraffin oil and general organic solvents can be used, in addition to the fact that the emulsion dispersant is substantially dissolved and the resulting polyamide fine particles are not dissolved. Moreover, even if it is a solvent which melt | dissolves in the solvent of a 1st solution, it can also be used if it adjusts to precipitate a polyamide by mixing with the poor solvent of a polymer.

The concentration of the emulsifying dispersant in the second solution may be appropriately set according to the type of polyamide used, the concentration of the first solution, and the like, but is usually about 0.05 to 10% by weight, preferably 0.2 to 5% by weight. If the concentration of the emulsion dispersant is less than 0.05% by weight, the spherical particles are aggregated and coalesced. If the concentration of the emulsion dispersant is 10% by weight or more, the economical efficiency is lowered, and there is a hassle of removal in a later process.

(2) second process

In the second step, the first solution and the second solution are mixed to form a polymer emulsion solution from the mixed solution by the stirring means. The mixing ratio of the first solution and the second solution can be appropriately changed depending on the type of polyamide, the concentration of each solution, and the like. Usually, the weight ratio is about 1: 1 to 1:50, preferably 1: 2 to 1:15. It may mix so that it may become a weight ratio. If the mixing ratio of the first solution and the second solution is 1: 1 weight ratio or less, it is impossible to form the emulsified particles. If the mixing ratio of the first solution and the second solution is 1:50 weight ratio or more, the size of the reaction tank is increased so that the yield is decreased. do.

The stirring means of the second step is mechanical stirring by a stirrer, it is possible to refine the average particle diameter by adjusting the stirring speed by a homomixer. A homomixer can employ | adopt a well-known stirring apparatus and operation conditions as it is. The rotational speed of the stirrer may be appropriately set in accordance with the desired particle size and the like, and is usually about 1,000 to 20,000 rpm, preferably 2,000 to 10,000 rpm. If the rotational speed of the stirrer is less than 1,000rpm, the size of the emulsion particles formed is too large to obtain the desired particle size, if the rotational speed of the stirrer is more than 20,000rpm overloading the stirrer is inferior in economic efficiency.

Another embodiment of the stirring means of the second step is the ultrasonic stirring by the ultrasonic generator, it is possible to refine the average particle diameter by adjusting the stirring speed by the ultrasonic stirring. Ultrasonic stirring can employ | adopt a well-known stirring apparatus and operation conditions as it is. The frequency of the ultrasonic generator may be appropriately set in accordance with the desired particle size and the like, and usually, about 20 to 130 KHz, and preferably 30 to 80 KHz. Ultrasonic agitation can perform finer agitation than mechanical agitation, and other various agitation means can be used in addition to the ultrasonic agitation and mechanical agitation.

The temperature in the second step is not particularly limited and may be usually performed at 15 to 30 ° C. The emulsification time should be about 10 to 30 minutes, preferably 5 to 15 minutes, when the emulsion is formed. If the emulsification time is 10 seconds or less, the stability of the emulsified particles is lowered. Will increase the likelihood.

In the second step, the present invention can further add a poor solvent of polyamide to the mixed solution. Depending on the type of solvent used in the first solution or the second solution, the polyamide spherical fine particles may not be precipitated or are difficult to precipitate. In this case, the polyamide spherical fine particles may be more efficiently formed by adding a poor solvent of polyamide. Can be precipitated. The poor solvent added to the mixed solution is not particularly limited and may be appropriately selected depending on the kind of polyamide produced, the solvent used for the first solution, the second solution, and the like.

(3) Third process

In the third step, polyamide spherical fine particles are precipitated while being removed out of the reaction system by heating and evaporating the organic solvent of the first solution from the emulsion dispersion. The heating temperature for the emulsion dispersion varies depending on the type of the solvent used in the first solution, but is usually about 80 to 150 ° C.

If the heating temperature is 80 ° C. or lower, the solvent of the first solution is less likely to evaporate. If the heating temperature is 150 ° C. or higher, the emulsion dispersant may be less efficient, causing coagulation between particles.

The stirring time may be performed until the precipitation of polyamide spherical fine particles is substantially completed. Usually, it is about 30 to 360 minutes, but there is no problem even if it is outside this range. However, when the stirring time is 30 minutes or less, the solvent of the first solution is not completely volatilized. In addition, if the stirring time is 360 minutes or more, there is a possibility that the possibility of occurrence of coagulation between particles increases.

The polyamide spherical fine particles precipitated in the third step may be recovered by solid-liquid separation according to a known method such as centrifugation. The polyamide fine particles obtained in the third step are all spherically formed, and the average particle diameter is usually within 0.005 to 80 µm (preferably 0.1 to 20 µm) and has excellent monodispersity. According to the present invention, the resulting fine particles exhibit excellent moisture contamination hygroscopicity and excellent sliding properties from their smooth surface shape due to their chemical structure.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are for illustration only and should not be understood as limiting the scope of the invention.

Example 1

As a first solution, 10 ml of a polymer solution dissolved in formic acid (polyamide: formic acid = 1: 30 weight ratio) and 20 ml of a 0.5% sorbitan monooleate-containing dodecane solution were prepared as a second solution. Both solutions were then mixed at 25 ° C. to prepare an emulsion with a homomixer (2,500 rpm). The prepared emulsion precipitated polyamide spherical microparticles | fine-particles by stirring at 110 degreeC for 60 minutes. Then, the precipitate was collect | recovered by the centrifugal method, and microparticles | fine-particles were obtained by drying under reduced pressure.

By observing the precipitated fine particles with a scanning electron microscope, it was confirmed that the polyamide spherical fine particles were composed of spherical particles having excellent monodisperse phase of about 1 μm. The observation result is shown in FIG.

Example 2

The preparation was carried out in the same manner as in Example 1, except that stirring was performed using an ultrasonic generator (28 Hz). Then, the precipitate was collect | recovered by the centrifugal method, and microparticles | fine-particles were obtained by drying under reduced pressure.

By observing the precipitated fine particles with a scanning electron microscope, it was confirmed that the polyamide spherical fine particles were composed of spherical particles having excellent monodisperse phase of about 700 nm. The observation result is shown in FIG.

According to the production method of the present invention, polyamide spherical fine particles can be produced. In addition, the production method of the present invention can control the desired particle size and its distribution form from the micrometer to the nanometer region by appropriately adjusting the conditions between the respective processes.

The polyamide spherical microparticles | fine-particles obtained by this invention can be used as a polymeric additive for cosmetics, and it becomes possible to use it widely for various other uses. For example, it is also useful for electrical / electronic materials, medical materials, various filter materials, chromatography materials, spacers, film additives, composite additives, polyamide varnish additives, and the like.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims. .

Claims (7)

In the method for producing polyamide spherical fine particles from a polyamide polymer, (a) a first step of preparing a first solution containing a polyamide polymer and a second solution containing an emulsion dispersant, respectively; (b) a second step of preparing an emulsion from the mixed solution by stirring means by mixing the first solution and the second solution, and and (c) a third step of depositing polyamide spherical fine particles by evaporating the solvent from the prepared emulsion. The method of claim 1, The polyamide polymer of the first solution of the first step is a nylon-based polymer from lactam or the like and a non-nylon-based polymer from acid and diamine. The method of claim 1, The solvent of the first solution includes at least one of formic acid, concentrated sulfuric acid, and concentrated nitric acid, and the polyamide spherical microparticles are produced in a ratio of 1: 3 to 1: 300 by weight. The method of claim 1, The solvent of the second solution includes at least one of a group consisting of a high molecular stereoscopic emulsifying agent having a high affinity with the solvent of the second solution, and an anionic, cationic and nonionic low molecular electrostatic emulsifying agent, A method for producing the polyamide spherical fine particles, characterized in that the concentration of the emulsion dispersant in the solution is 0.05 to 10% by weight. The method according to any one of claims 1 to 4, The stirring means is mechanical stirring by a stirrer, the mixing ratio of the first solution and the second solution is 1: 1 to 1:50 weight ratio, the rotation speed of the stirrer is 1,000 to 20,000 rpm, the stirring time is 30 to 360 minutes Method for producing the polyamide spherical fine particles, characterized in that. The method according to any one of claims 1 to 4, The stirring means is ultrasonic stirring by an ultrasonic generator, the mixing ratio of the first solution and the second solution is 1: 1 to 1:50 weight ratio, the stirring time is 30 to 360 minutes, the polyamide spherical fine particles Manufacturing method. The method of claim 1, The polyamide spherical microparticles | fine-particles are precipitated by heating and evaporating the organic solvent of a 1st solution to 80-150 degreeC from the emulsion of the said 3rd process.