JP2003277417A - Nonspherical bulk polymer fine particle and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide nonspherical bulk polymer fine particles giving viscosity characteristics, light-scattering characteristics, and specific surface characteristics to a paint or a cosmetic, when added thereto, especially giving good skin touch with a moisture feeling to the cosmetic. <P>SOLUTION: The nonspherical bulk polymer fine particles are produced by dissolving 1-30 pts.wt. of a low-crystalline elastomer or a liquid rubber in a monomer mixture comprising 40-90 pts.wt. of a hydrophobic polymerizable vinyl monomer and 1-40 pts.wt. of a cross-linkable monomer, then conducting suspension polymerization thereof in an aqueous medium. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to non-spherical polymer particles and their production. The polymer fine particles are effective for being added to paints and cosmetics to give them a viscous property, a light scattering property, a unique surface property, and a moist feel to the skin.

[0002]

2. Description of the Related Art Polymer fine particles having an average particle diameter of 2 to 300 μm are usually prepared by forcibly dispersing a liquid polymerizable vinyl monomer in an aqueous medium in the presence of a dispersion stabilizer with a homomixer to form droplets. It is produced by suspension polymerization. In the production of polymer particles by this suspension polymerization, the liquid polymerizable vinyl monomer usually becomes spherical due to its surface tension in an aqueous medium, and the polymer particles obtained by polymerization also become spherical particles having a smooth surface. .
As a method for producing bowl-shaped polymer particles, a hydrophilic vinyl monomer is used as the polymerizable vinyl monomer, and the crosslinkable monomer is subjected to suspension polymerization in the presence of an oil-soluble substance (Patent Document 1)
61-87734, JP-A-2-255704) are known, but non-spherical polymer particles having irregular irregularities are not yet known.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide novel non-spherical polymer particles and a method for producing non-spherical polymer particles by suspension polymerization.

[0004]

The present inventors have previously reported that
Novel spherical polymer fine particles having a regular wrinkled structure on the fine particle surface and a method for producing the same (Japanese Patent Laid-Open No. 11-14011)
No. 39), but this time, when a low crystalline elastomer or liquid rubber was dissolved in a mixture of hydrophobic polymerizable vinyl monomer and crosslinkable monomer and suspension polymerization was performed in an aqueous medium, Unlike the one with a regular wrinkle-like surface, non-spherical polymer particles having rounded irregular irregularities on the surface can be obtained, and the non-spherical polymer fine particles have a regular wrinkle-like structure It has different viscosity characteristics, light scattering characteristics, and surface characteristics from those of
It has been found that it gives a unique feel to the skin when mixed with cosmetics, and the present invention has been completed. That is, the present invention provides (1) non-spherical lump polymer particles,
(2) Particle size is 0.5 to 300 μm Average particle size is 2-1
In the range of 00 μm, the non-spherical lump polymer particles according to (1) above, and (3) the aspect ratio of the particles is from 1.10.
The non-spherical lump polymer fine particles according to (1) or (2), which has a sphericity of 5.00 or less and a sphericity of 65 or less; m
The non-spherical lump polymer particles according to any one of (1) to (3) above in the range of m ² , (5) 40 to 90 parts by weight of the hydrophobic polymerizable vinyl monomer and 1 to 1 of the crosslinkable monomer.
A method for producing fine non-spherical polymer particles in which 1 to 30 parts by weight of a low crystalline elastomer or liquid rubber is dissolved in a monomer mixture consisting of 40 parts by weight and suspension polymerization is carried out in an aqueous medium, (6) a polymerizable vinyl monomer is The production method according to the above (5), which is an alkyl (meth) acrylate ester;
(7) The production method according to (5) above, wherein the crosslinkable monomer is alkylene glycol di (meth) acrylate,
(8) A cosmetic comprising the non-spherical lump polymer particles according to any one of (1) to (4).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Non-spherical polymer particles in the non-spherical polymer particles of the present invention do not include particles having a true spherical shape in a certain proportion or more and have rounded irregular irregularities on the surface. It means that the lumpy fine particles are contained in a certain proportion or more. That is, not thread-shaped, needle-shaped, rod-shaped, bowl-shaped, extremely flattened, etc., and there are no sharp ridges or protrusions such as angular protrusions or crushed grains, and a lump having a plurality of rounded irregularities on the surface, For example, it has a shape such as a rice grain or potato, and a specific example thereof has a shape as shown in FIGS. 1 and 2.

The average particle size is in the range of 2 to 100 μm, and the particle size is preferably in the range of 0.5 to 300 μm, more preferably the average particle size is in the range of 3 to 50.
μm, and the particle size is in the range of 1 to 100 μm, and more preferably, the average particle size is in the range of 3 to 30 μm.
m, and the particle size is in the range of 1 to 70 μm. If it is smaller than this range, a gritty feel is not preferable, and if it is larger than this range, a rough feel is not preferable. The fine particles of the present invention preferably have an aspect ratio of 1.10 to 5.00, more preferably 1.20 to 4.00. If it is lower than 1.10, the rolling effect is too great,
A moist feel cannot be obtained, and when it is higher than 5.00, a gritty feel is often generated, which is not preferable.

To measure the aspect ratio, the ratio of the major axis (equivalent diameter of circle) to the thickness of particles is calculated by the following formula. Aspect ratio = equivalent circle diameter (major axis) / thickness (minor axis) The fine particles of the present invention preferably have a sphericity of 65 or less, more preferably 60 or less. If the sphericity is higher than this, the rolling effect is too great and a moist feel cannot be obtained.

To measure the sphericity, electron micrographs of solid particles are taken with a scanning electron microscope, 100 particles in which the particles do not overlap each other are randomly selected, and the projected image of the particles is a perfect circle. Alternatively, the circumscribed circle of the projected image is drawn, and the true number of particles is determined by the number of those having a shape in which the outline of the projected image is included between the circumscribed circle and a concentric circle having a radius of 90% of the circumscribed circle Sphericality. The compressive strength of the particles at a deformation rate of 20% is preferably in the range of 0.1 to 3.0 kgf / mm ² , and more preferably 0.3 to 2.8.
It is kgf / mm ² . If the compressive strength is lower than this, the net feel is not preferable, and if the compressive strength is higher, the moist feeling is not sufficiently produced, which is not preferable. The compressive strength is measured by measuring the compressive strength when the deformation rate of the particles at 25 ° C. is 20%, for example, with a micro-compressive strength measuring instrument such as MCTM-500 manufactured by Shimadzu Corporation.

Examples of the hydrophobic polymerizable vinyl monomer used in the present invention include aromatic vinyl monomers such as styrene, α-methylstyrene and vinyltoluene, methyl acrylate, ethyl acrylate and butyl acrylate. Alkyl acrylates, methyl methacrylate, ethyl methacrylate, methacrylic acid alkyl esters such as butyl methacrylate, vinyl ester-based monomers such as vinyl acetate and vinyl propionate, vinyl cyan-based monomers such as (meth) acrylonitrile Use a hydrophobic vinyl monomer that does not have a hydrophilic group such as a hydroxyl group, a carboxyl group, an amino group, and a sulfonic acid group in the molecule such as a vinyl halide monomer such as a monomer, vinyl chloride, or vinylidene chloride. be able to.

Examples of the crosslinkable monomer used in the present invention include aromatic divinyl compounds such as divinylbenzene and divinyltoluene, and alkylene glycol di (meth) acrylates such as ethylene glycol di (meth) acrylate and diethylene glycol di (meth) acrylate. Examples thereof include compounds having two or more polymerizable unsaturated bonds in one molecule such as trimethylolpropane tri (meth) acrylate, tri (meth) acrylate such as pentaerythritol tetra (meth) acrylate, and tetra (meth) acrylate. .

Examples of the low crystalline elastomer and liquid rubber used in the present invention include polyisoprene, polybutene and polybutadiene, synthetic rubbers which are liquid at room temperature, such as liquid chloroprene rubber and liquid nitrile rubber.
Examples include liquid fluororubber, liquid silicone rubber, liquid isoprene rubber and the like. These elastomers and rubbers can be used alone or in combination of two or more. The amount of each of the hydrophobic polymerizable vinyl monomer, the crosslinkable monomer, and the low crystalline elastomer or liquid rubber used is usually 40 to 90: 1 to 40: 1 to 3 by weight ratio.
0, preferably 45 to 80: 3 to 30: 3 to 20. If the amounts of the hydrophobic polymerizable vinyl monomer, the crosslinkable monomer, the low crystalline elastomer or the liquid rubber used are out of the above ranges, fine particles of non-spherical polymer particles cannot be obtained.

If necessary, an oil-soluble solvent or a styrenic elastomer compatible with the monomer mixture can be used in order to promote phase separation in the droplets during polymerization. The styrenic elastomer must be soluble in a mixture of hydrophobic polymerizable vinyl monomer and crosslinkable monomer at room temperature or under heating. Examples thereof include copolymer elastomers such as styrene and butadiene and isoprene. Among them, styrene-butadiene-styrene, styrene-isoprene-styrene, styrene- (ethylene / butylene) -styrene, styrene-
A block copolymer elastomer such as (ethylene / propylene) -styrene is particularly preferable. The molecular weight of these styrene elastomers is not particularly limited as long as it can be dissolved in a liquid mixture of a hydrophobic polymerizable vinyl monomer at room temperature or by heating, but the viscosity of a toluene solution having a polymer concentration of 25% is 1000 mPa · s, It is preferable that the viscosity of the toluene solution having a polymer concentration of 15% is up to 5000 mPa · s. These styrene-based elastomers can be used alone or in combination of two or more.

Examples of the oil-soluble solvent include esters such as methyl acetate, ethyl acetate, butyl butyrate and isoamyl butyrate: ketones such as diethyl ketone and methyl ethyl ketone: aromatic hydrocarbons such as benzene, toluene and xylene: Aliphatic hydrocarbons such as butane, pentane, and hexane: long-chain alkyl derivatives such as olive oil, latte oil, coconut oil, castor oil, and the like. These oil-soluble solvents are 5 to 100 parts by weight of the monomer mixture.
About 20 parts by weight is used. A dispersion of a solution of each of the monomers used in the present invention and a low crystalline elastomer or liquid rubber in an aqueous medium is subjected to suspension polymerization in the next step. Raw material droplets and generated polymer particles In order to improve the dispersibility of the above, suitable amounts of various surfactants and dispersion stabilizers such as polymer protective colloids are used.

As the dispersion stabilizer, surfactants such as sodium dodecylbenzene sulfonate and sodium lauryl sulfate, water-soluble polymers such as gelatin, methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol and polyacrylate, tricalcium phosphate, A poorly water-soluble inorganic substance such as magnesium carbonate is used. These dispersion stabilizers may be used alone or in combination of two or more. These dispersion stabilizers can be stably polymerized in the amounts used in ordinary suspension polymerization.

In the suspension polymerization of the present invention, a suitable amount of a chain transfer agent, a polymerization inhibitor or the like may be used in addition to the weight initiator, if necessary. As the polymerization initiator, those usually used in this kind of reaction, for example, peroxide initiators such as benzoyl peroxide and lauroyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-iso Examples thereof include azo polymerization initiators such as valeronitrile. These polymerization initiators are used by being dissolved in a polymerizable monomer. Chain transfer agents may also be those commonly used in this type of reaction, for example, monothiol, polythiol, xanthogen disulfide, thiuram disulfide, mercaptoacetic acid 2-ethylhexyl ester, octanoic acid 2-mercaptoethyl ester, mercaptoacetic acid methoxybutyl ester, mercapto. Propionic acid methoxybutyl ester, α-methylstyrene dimer, terpinolene and the like are preferably used. Further, as the polymerization inhibitor, for example, an appropriate amount of a commonly used polymerization inhibitor such as sodium nitrite, sodium sulfite, cupric chloride, etc. is used.

The average particle size of the polymer fine particles is a droplet size which is dispersion-stabilized by dispersing a mixed solution of a hydrophobic polymerizable vinyl monomer, a crosslinkable monomer, a low crystalline elastomer or a liquid rubber and a styrene elastomer. Those having approximately the same diameter can be obtained by the subsequent polymerization reaction. The size of the droplet size can be arbitrarily controlled by selecting the type and amount of the dispersion stabilizer and the rotation speed of a forced disperser such as a homomixer. By adjusting droplets having a target particle size and then polymerizing them, polymer fine particles having a particle size of 2 to 300 μm can be arbitrarily produced. The polymerization temperature in the polymerization reaction of the present invention varies depending on the type of the polymerization initiator used, the monomer, the polymerization inhibitor, the chain transfer agent, etc., which are optionally added, but is usually 30 to 100 ° C., and preferably 50 to 50 ° C. 9
It is 0 ° C. After the suspension polymerization, the polymer particles are separated by filtration, washed with water and dried to obtain a dry powder composed of non-spherical polymer particles.

[0017]

EXAMPLES The present invention will be described more specifically below, but the present invention is not limited to these examples.
In the examples, "part" represents part by weight. Example 1 20 parts of polybutene (manufactured by Nippon Petrochemical Co., Ltd., Nisseki Polybutene HV300) and 0.5 parts of azobisisovaleronitrile were dissolved in a mixed solution of 75 parts of methyl methacrylate and 5 parts of ethylene glycol dimethacrylate. Polyvinyl alcohol (PVA20 manufactured by Kuraray Co., Ltd.)
5) 10% aqueous solution of 25 parts, 1% ethylene oxide-
1 part of propylene oxide-based nonionic surfactant (Pronone 208, manufactured by NOF CORPORATION) and ion-exchanged water 2
75 parts were injected. The obtained mixed liquid was stirred for 20 minutes at 7,000 rpm using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare a raw material dispersion liquid. This raw material dispersion was charged into a polymerization reaction vessel equipped with a stirrer and a reflux condenser,
While stirring under a nitrogen stream, the temperature was raised to 80 ° C. and polymerization was carried out for 3 hours. The obtained polymer fine particle dispersion is dehydrated, washed, dried, and sieved to obtain an average particle size of 9 μm and a sphericity of 4
0, the aspect ratio is 1.20, and the compressive strength at 20% deformation is 1.65 kgf / mm ² rice polymer particles [Fig. 1] 8
5 parts by weight were obtained. These particles are referred to as non-spherical polymer particles A
And

Example 2 Polybutene (manufactured by Nippon Petrochemical Co., Ltd., Nisseki Polybutene HV300) 20 parts styrene-isoprene-styrene block copolymer (Shell Japan Co., Ltd.) ), D-1107CP) (10 parts) and azobisisovaleronitrile (0.5 parts) were dissolved in the same manner as in Example 1 (however, the rotation speed of the homomixer was 9,000 rpm) to obtain an average particle diameter. Is 11 μm and sphericity is 5
5, 86 parts by weight of non-agglomerated polymer fine particles (FIG. 2) having an aspect ratio of 1.40 and a compressive strength at 20% deformation of 0.97 kgf / mm ² were obtained. These particles are referred to as non-spherical polymer particles B.

Comparative Example 1 In Example 1, the use of low crystalline elastomer or liquid rubber
Same operation except that the dose was changed from 20 to 0
It was The obtained particles have an average particle size of 11 μm, a sphericity of 92,
The aspect ratio is 1.00 and the compressive strength at 20% deformation is
3.47kgf / mm ^TwoIt becomes a spherical polymer of
It was not possible to obtain mar fine particles. (Figure 3)

Comparative Example 2 The same operation as in Example 1 was carried out except that 5 parts of ethylene glycol dimethacrylate was not added. 20 with an average particle size of 9 μm, a sphericity of 81 and an aspect ratio of 1.02
As a result, 86 parts by weight of spherical polymer fine particles (FIG. 4) having a compressive strength at the time of deformation of 3.21 kgf / mm ² were obtained. The surface of these particles was smooth, and non-agglomerated polymer particles could not be obtained. (Figure 4)

Next, a compounding example using these non-spherical polymer particles will be shown. Formulation Example 1 Oily compact foundation wt% Carnauba wax 4.0 Solid paraffin 4.0 Cetanol 4.0 Lanolin 7.0 Liquid paraffin 5.0 Behenyl alcohol 3.0 Activator 2.0 Pigment paste 25.0 Non-spherical polymer particles A 35.0 Sericite 10.0 Fragrance 1.0 An oily compact foundation was produced with the above ingredients.

Formulation Example 2 Cream wt% Decamethylsoclopentasiloxane 61.0 Octylmethoxycinnamate 2.0 Dimethylpolysiloxane 6.0 Polymethylsilsesquioxane powder 4.0 Non-spherical lump polymer particles B 6.0 Glycerin 20.0 Fragrance 1.0 Purified water An appropriate amount of the cream was prepared to prepare a cream. The cosmetics produced in Formulation Example 1 and Formulation Example 2 were not sticky at the time of application, were not sticky to the skin after use, and were obtained with a very moist and silky feel that has never been seen before. It turned out to be very useful.

[0023]

According to the present invention, a low crystalline elastomer or liquid rubber is dissolved in a mixture of a hydrophobic polymerizable vinyl polymer and a crosslinkable monomer, and the suspension is polymerized by suspension polymerization in an aqueous medium. Non-spherical polymer particles can be obtained. The non-spherical polymer particles having a unique shape thus obtained give a uniform composition that does not cause layer separation when blended in, for example, paints or cosmetics, and its viscosity characteristics, light scattering characteristics and surface characteristics are It can be advantageously used for changing and adjusting. In particular, in cosmetics blended with cosmetics, a soft and silky feel, which polymethylmethacrylate fine particles and polystyrene fine particles do not have, can be obtained.

[Brief description of drawings]

FIG. 1 is an electron micrograph of polymer fine particles obtained in Example 1.

2 is an electron micrograph of polymer fine particles obtained in Example 2. FIG.

FIG. 3 is an electron micrograph of polymer fine particles obtained in Comparative Example 1.

FIG. 4 is an electron micrograph of polymer fine particles obtained in Comparative Example 2.

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Claims (8)

[Claims] 1. Non-spherical polymer particles. 2. The non-spherical lump polymer fine particles according to claim 1, wherein the particle diameter is in the range of 0.5 to 300 μm and the average particle diameter is in the range of 2 to 100 μm. 3. The aspect ratio of fine particles is 1.10 to 5.0.
The non-spherical lump polymer particles according to claim 1 or 2, wherein the sphericity is 0 and the sphericity is 65 or less. 4. The compressive strength of particles at a deformation rate of 20% is
The non-spherical lump polymer particles according to any one of claims 1 to 3, which are in the range of 0.1 to 3.0 kgf / mm ² . 5. A hydrophobic polymerizable vinyl monomer 40-90.
A method for producing fine non-spherical polymer particles, wherein 1 to 30 parts by weight of a low crystalline elastomer or liquid rubber is dissolved in a monomer mixture consisting of 1 part by weight to 40 parts by weight of a crosslinkable monomer, and suspension polymerization is carried out in an aqueous medium. 6. The method according to claim 5, wherein the polymerizable vinyl monomer is a (meth) acrylic acid alkyl ester. 7. The method according to claim 5, wherein the crosslinkable monomer is alkylene glycol di (meth) acrylate. 8. A cosmetic containing the non-spherical lump polymer particles according to any one of claims 1 to 4.