JP2007112888A - Polymer fine particles with a smooth surface and a spherical to elliptical shape - Google Patents

Abstract

【Task】
The problem to be solved by the present invention is not related to the production method of the thermoplastic polymer and the degree of polymerization, but from a general-purpose polymer as a raw material, polymer particles having a narrow particle size distribution width and an average particle size of 50 μm or less are inexpensive. It is to provide a simple manufacturing method.
[Solution]
The fine particle of the present invention is a thermoplastic addition polymer containing a normal temperature gas unsaturated compound raw material, a molecular weight of 10,000 or more, and a thermoplastic condensation polymer, an average particle size of 50 μm or less, a small particle size distribution width, a surface Are fine particles that are smooth, spherical to elliptical. Preferably, the room temperature gas unsaturated compound raw material is at least one of ethylene, propylene, isopropylene and butylene, and is used as a light scattering material for a diffusion film, a cosmetic slip effect agent, and an antiblocking agent. Further, it is a method for producing polymer fine particles comprising a system in which a molten polymer and a dispersion medium form a metastable emulsion under a shearing stress, and cooling and solidifying in a state where the emulsion is maintained.

Description

  The present invention relates to polymer fine particles for use such as fine particles for light scattering fine particles, fine particles for cosmetics and anti-blocking fine particles, and a method for producing the same.

  Physical granulation using a hammer mill or the like is generally used for granulating the polymer, but the polymer is soft and cannot be finely pulverized. Further, in the case of fine pulverization, a jet mill is used that cools to low temperature with liquid nitrogen or liquid natural gas, raises the hardness, and collides the particles in a fragile state for pulverization. However, the particle shape obtained by this method is indefinite, and there is a drawback that the surface is not smooth. Further, an expensive freeze pulverization machine is used, and the productivity is low and the processing cost is expensive, which is not economically preferable. Furthermore, there is a risk of contamination.

  As a production method capable of obtaining a particle shape having a smooth surface, emulsion polymerization is generally used. However, the emulsion polymerization method is limited to addition polymerization products only, and cannot be applied to condensation polymerization products. A common emulsion polymer monomer is a normal temperature liquid acrylic type, normal temperature gas raw material polyolefin is expensive reactor, and as described in Patent Document 1, the polymerization catalyst is usually deactivated by water, This is economically and practically disadvantageous because it requires a special catalyst containing a rare earth element in which water does not become a catalyst poison. In addition, there is an inevitable disadvantage that additives such as emulsifiers and colloids of the emulsion polymer are unavoidably mixed.

  Chemical pulverization regardless of the type of polymer is a method of precipitating a polymer that has exceeded solubility by cooling the polymer solution, and the process is long and the yield is low. Further, even if the nylon resin particles described in Patent Document 2 are spherical at first glance, when viewed in detail, the precipitation is anisotropic and only irregular shaped particles can be obtained, and particles with smooth surfaces cannot be obtained. . In addition, there is a disadvantage that the particle size distribution is widened because the previously precipitated particles become nuclei during the precipitation and are sequentially precipitated.

Polyethylene wax and polypropylene wax, which are low molecular weight polymer olefins, have a molecular weight of less than 10,000, and usually 5,000 or less. Such low-molecular-weight polymer olefins are dissolved by heating under pressure in a solvent such as liquid paraffin, resulting in a metastable emulsion state during cooling, and by rapid cooling, fine particles with a spherical and smooth surface are obtained. Can be manufactured. However, when the molecular weight is 10,000 or more, this method cannot be used because it does not dissolve in heated paraffin oil.
Special table 2003-517062 gazette JP-A-5-32795

The problem to be solved by the present invention is not related to the production method of the thermoplastic polymer and the degree of polymerization, but from a general-purpose polymer as a raw material, polymer particles having a narrow particle size distribution width and an average particle size of 50 μm or less are inexpensive. It is to provide a simple manufacturing method.

  The fine particle of the present invention is a thermoplastic addition polymer containing a normal temperature gas unsaturated compound raw material, a molecular weight of 10,000 or more, and a thermoplastic condensation polymer, an average particle size of 50 μm or less, a small particle size distribution width, a surface Are fine particles that are smooth, spherical to elliptical. Preferably, the raw material for the room temperature gas unsaturated compound is at least one of ethylene, propylene, isopropylene and butylene, for light scattering of lenticular screens, diffusion films, etc., improvement of cosmetic extension, wrinkle effect and slip that changes tactile sensation Used as an effect agent and anti-blocking agent. Further, it is a method for producing polymer fine particles comprising a system in which a molten polymer and a dispersion medium form a metastable emulsion under a shearing stress, and cooling and solidifying in a state where the emulsion is maintained.

  The polymer fine particles of the present invention can be supplied at a low cost since a general-purpose polymer is used as a raw material and a general twin screw extruder is used. In addition, since it is cooled rapidly while maintaining a metastable emulsion state in a molten state, spherical or oval spherical fine particles having a smooth surface are obtained, and the particle size distribution width is small, and light scattering, cosmetics, antiblocking agents, toners, It can be used as a raw material for inks and paints.

  The polymer fine particle of the present invention is a thermoplastic addition polymer containing a normal temperature gas unsaturated compound raw material, having a molecular weight of 10,000 or more, and a thermoplastic condensation polymer, an average particle size of 50 μm or less, and a small particle size distribution width. Fine particles that have a smooth surface and a spherical to elliptical shape. Preferably, the ambient temperature gas unsaturated compound raw material is at least one of ethylene, propylene, isopropylene and butylene, and the polymer A having affinity for the dispersion medium and the polymer having affinity for the polymer mainly forming fine particles. 1% by weight or more of a block copolymer consisting of B is contained. It is used for light scattering of lenticular screens, diffusing films, etc., for improving the extension of cosmetics, for wrinkle effects and for slipping effect agents that change tactile feel, and as an anti-blocking agent. Further, it is a method for producing polymer fine particles comprising a system in which a molten polymer and a dispersion medium form a metastable emulsion under a shearing stress, and cooling and solidifying in a state where the emulsion is maintained.

  The raw material polymer of the present invention may be a thermoplastic polymer, and includes addition polymers such as polyolefin and polystyrene, polycondensation products such as polyester, polyamide, and polyether, and copolymers, which are also commercially available as general-purpose resins. Has been. In addition, since it is a general-purpose resin, a masterbatch containing a color pigment is also commercially available and can be used at low cost and is suitable as a raw material for toner, ink, paint and the like.

  Production of polyolefins having a large molecular weight of normal-temperature gas monomers such as ethylene, propylene, butylene, and spherical fine particles having a smooth surface of a condensation polymerization product is difficult to produce by conventional methods, and is the sole place of the present invention.

  Since the block copolymer comprising the polymer A having affinity for the dispersion medium and the polymer B having affinity for the polymer mainly forming fine particles differs depending on the polymer A and the polymer B, it is necessary to select appropriately. In the case of producing propylene fine particles using Hysol SAS, a benzene compound manufactured by Nippon Oil Corporation, as a dispersion medium, for example, Septon (trade name) in which styrene and ethylene propylene block copolymers are commercially available from Kuraray Co., Ltd. It is good to use. Septon is relatively inexpensive because it is used in large quantities for various purposes such as hot-melt raw materials. Examples of the block copolymer for the condensation polymer include, for example, various thermoplastic urethanes, polybutylene terephthalate / polyol block copolymer from Toray Co., Ltd., Hytrel (trade name), and polyamide / polyol block copolymer from Arkema Co., Ltd. It is already commercially available in large quantities as Bevacs (trade name) or the like. As the dispersion medium, trioxane, glycerin and the like are preferable.

  Since the block copolymer acts as a polymer surfactant and forms a film-like interface, the molecular weight is preferably small. Preferably, it is 1% by weight or more of the total weight of the polymer fine particles. When this block copolymer is used in combination, the selection range of the dispersion medium and the fine particle polymer is widened, which is preferable.

  Since the dispersion medium is produced by heating above the melting point of the polymer, a heat-resistant dispersion medium is preferable. Further, if there is no affinity for the polymer, the phase separation occurs when the shearing force is lost, and the emulsion is destroyed. Therefore, it is necessary to select appropriately. The dispersion medium is often washed and reused. It is preferable to use a dispersion medium used in the next application because this washing step can be omitted and secondary aggregation of fine particles can be prevented. For example, glycerin and low-mole polyethylene glycol fatty acid esters that are frequently used in cosmetics are good examples.

  As the mixing stirrer used in the present invention, a general twin-screw extruder, a kneader or the like can be used. Among them, a twin screw extruder having a large shearing force and a short residence time until taking out is preferable. Further, a twin screw extruder with a metering pump such as a plunger or a gear pump capable of injecting the dispersion medium liquid in the middle is preferable.

  The raw polymer is pelletized and metered from the hopper, but the block copolymer is metered at the same time. The unit of the twin-screw extruder is selected as a unit having good stirring efficiency, and the mixing and stirring set maximum temperature is preferably equal to or higher than the melting point of the polymer. However, since the heat is generated by shearing force, the substantial temperature only needs to be maintained above the melting point. After the mixing and stirring steps, it is preferable to quickly discharge and cool, and after taking out from the nozzle in a cord shape, it is preferable to cool and cut with a water-cooling or underwater cutter.

  The average diameter of the fine particles was obtained by sufficiently diluting the fine particles and then dispersing with ultrasonic waves, and analyzing the photographed SEM photograph with the Scion image.

Example 1
30mmφ with underwater cutter, Kobe Steel Co., Ltd. twin screw extruder, maximum setting temperature 250 ° C, discharge rate 20kg / hour, rotation speed 200rpm, 30 parts by weight of polypropylene with a molecular weight of about 200,000 at MFR8, 70 parts by weight of dispersion medium Idemitsu Kosan Co., Ltd. paraffin oil (Daphney oil CP12N) is injected into the part with a plunger pump, melted and mixed, stirred, extruded from a nozzle in a metastable emulsion state, cut in water, The YS oil was washed with acetone and dried to produce polypropylene fine particles of the present invention. As a result of image analysis of the SEM photograph, the obtained fine particles were almost spherical with a smooth surface with a spherical equivalent average radius of 38 μm. The dispersion medium paraffin oil was nonpolar and had a good affinity with polypropylene.

(Comparative Example 1)
In the same manner as in Example 1, the dispersion medium was changed to only glycerin and produced. However, glycerin and polypropylene having high polarity caused phase separation, and fine particles could not be produced.

(Example 2)
In the same manner as in Example 1, the dispersion medium is Hysol SAS, a benzene compound manufactured by Nippon Oil Corporation, polypropylene is MFR1, LL polyethylene having a molecular weight of about 300,000, and Septon SEPS2002 of 5% by weight based on the weight of polyethylene is further added. The polyethylene fine particles of the present invention of the present invention were produced by changing only the addition. As a result of image analysis of the SEM photograph, the obtained fine particles were oval spherical with a smooth surface having a spherical equivalent average radius of 32 μm. Septon SEPS2002 is a block copolymer with a styrene content of 30%.

(Example 3)
Using a 30 mmφ with underwater cutter, Kobe Steel's twin screw extruder, maximum set temperature 230 ° C., discharge rate 20 kg / hour, rotational speed 200 rpm, IV value. 65 parts by weight of polybutylene terephthalate of 65, 6 parts by weight of polybutylene terephthalate / tetramethylene polyol block copolymer, 65 parts by weight of a dispersion medium trioxane are injected into the melted part with a plunger pump, and the mixture is mixed and stirred. Extruded from a nozzle in a stable emulsion state, cut in water, washed the dispersion medium trioxane with acetone, dried, and then produced polybutylene terephthalate fine particles of the present invention. As a result of image analysis of the SEM photograph, the obtained fine particles were almost spherical with a smooth surface having a spherical equivalent average radius of 2.7 μm.

Example 4
In accordance with JP-A-2004-217580, after mixing the component (a), apply three rolls to uniformly disperse, and then heat solubilize by heating to 90 ° C in advance and cool to room temperature. Add koji and c, knead and mix while heating to 80 ° C with a kneader, cool to room temperature, weigh in a metal pan, press mold under heating, powder-containing solid cosmetic Manufactured. About these, the adhesion to the puff and the adhesion to the skin were evaluated using a paneler. As compared with the comparative example in which the amount of mica was increased instead of the polyethylene fine particles of the present invention, it was found that the paste using the polyethylene fine particles of the present invention has a marked improvement.
Isorbitan sesquiolate 1.5 parts by weight, cetyl isooctanoate 18 parts by weight, titanium dioxide 25 parts by weight, ultramarine 0.5 parts by weight, bengara 0.7 parts by weight, yellow iron oxide 5 parts by weight 2 parts by weight of the polyethylene fine particles of the present invention, 5 parts by weight of cetyl isooctanoate 42.3 parts by weight of Jamaica

(Example 5)
According to Japanese Patent Laid-Open No. 2005-128577, a light diffusing ink having the following composition is applied to one side of a 25 μm thick polyethylene terephthalate film base material that has been subjected to easy adhesion treatment on both sides, and dried to form a light diffusing layer. Thereafter, a pressure-sensitive adhesive (BPS3233D manufactured by Toyo Ink Manufacturing Co., Ltd.) was applied to the other surface and dried to form a pressure-sensitive adhesive layer to obtain a light diffusion film. The thickness of the light diffusion layer of the light diffusion film is 15 μm after drying, and the thickness of the adhesive layer after drying is 20 μm. By using this film, the image was improved, the stray light was eliminated, the resolution was improved, and a clear feeling was obtained.
Light diffusion ink composition acrylic resin (Dianar BR-60 manufactured by Mitsubishi Rayon Co., Ltd.) 30 parts by weight of light diffusion fine particles
Polyester fine particles of the present invention of Example 3 7 parts by weight Methyl ethyl ketone 28 parts by weight Toluene 28 parts by weight Polyester resin (Byron 200, Byron 200) 30 parts by weight

(Example 6)
MFR3 LLDPE was dry blended with 1 part by weight of the polyester fine particles of the present invention of Example 3, and a film having a thickness of 15 μm was produced by a T-die method at 220 ° C. by a conventional method. Tacking was remarkable in the film not containing the polyester fine particles, but an excellent blocking effect was obtained by adding the polyester fine particles.

Claims (7)

A thermoplastic addition polymer containing an ambient temperature gas unsaturated compound raw material, a molecular weight of 10,000 or more, or a thermoplastic condensation polymer, an average particle size of 50 μm or less, a small particle size distribution width, and a smooth surface. Fine particles that are elliptical spherical. The fine particles according to claim 1, wherein the raw material for the room temperature gas unsaturated compound is at least one of ethylene, propylene, isopropylene and butylene. 2. The fine particles for light scattering according to claim 1, which are used for lenticular screens, diffusion films and the like. The fine particles for cosmetics according to claim 1, which are used as a slip effect agent for improving the elongation of cosmetics, the wrinkle effect, and the tactile sensation. The fine particles according to claim 1 used as an antiblocking agent. 2. The method for producing polymer fine particles according to claim 1, wherein the polymer melt and the dispersion medium are composed of a system that forms a metastable emulsion under shearing stress, and is cooled and solidified while maintaining the emulsion. 2. The fine particles according to claim 1, comprising 1% by weight or more of a block copolymer comprising a polymer A having an affinity for a dispersion medium and a polymer B having an affinity for a polymer mainly forming the fine particles.