JP2023033161A - Porous resin particle, production method of the same, personal care product including the same, heat insulation material and sound insulation material - Google Patents

Abstract

[Problem] Resin particles can express and control various properties such as weather resistance and light diffusivity depending on the monomers and shapes that constitute them. It is used in a wide range of applications such as light diffusing materials. In recent years, it has been reported that resin particles are made porous in order to improve the oil absorption capacity required when adding them to cosmetics. There is a need to improve their capabilities. An object of the present invention is to provide porous resin particles capable of exhibiting an excellent absorption capacity in the absorption and separation of liquid substances such as oil and water, and a method for producing the particles.
A porous resin particle having a cumulative pore volume of 1.5 to 5.0 ml/g and an average pore diameter of 0.1 to 2.0 μm.
[Selection figure] None

Description

The present invention relates to porous resin particles, methods of making the particles and personal care products containing the particles.

Resin particles can express and control various properties such as weather resistance and light diffusivity depending on the monomers and shapes that constitute them. Therefore, they are used as additives for cosmetics, matting materials for paints, and light diffusion materials for lighting covers and liquid crystal panels. It is used for a wide range of purposes such as In particular, attempts have been reported to increase the oil absorbency of resin particles added to cosmetics in order to improve the sebum-adsorbing properties and the ability to retain active ingredients of cosmetics.

For example, Patent Document 1 reports a spherical polymer having an average particle size of 1 to 50 μm and having one or more pores inside. Further, in Patent Document 2, a monomer mixture containing a plurality of monomers having a copolymerizable functional group is subjected to suspension polymerization in the presence of at least a non-polymerizable silicone compound, and , resin particles having roughened surfaces have been reported.

Furthermore, Patent Document 3 reports a cosmetic porous resin particle comprising a copolymer of methyl methacrylate and poly(ethylene glycol-propylene glycol) monomethacrylate and having an oil absorption of 135 ml/100 g.

JP-A-60-184004 WO16/006540 JP 2017-88501 A

However, it cannot be said that the porous resin particles reported in Patent Documents 1 to 3 have sufficient oil absorption for higher requirements. This is probably because conventional porous resin particles have a small space volume inside the particles, limiting the amount of oil absorption. The present invention was invented in view of the current state of the prior art, and its object is to provide porous resin particles capable of exhibiting an excellent absorption amount in the absorption and separation of liquid substances such as oil and water, and the porous resin particles. An object of the present invention is to provide a method for producing particles.

The present inventors have made intensive studies to achieve the above-mentioned objects, and found that the cumulative pore volume is 1.5 to 5.0 ml / g and the average pore diameter is 0.1 to 2.0 μm. The inventors have found that the porous resin particles can achieve the above object, and have completed the present invention.

That is, the present invention is achieved by the following means.
[1] Porous resin particles having a cumulative pore volume of 1.5 to 5.0 ml/g and an average pore diameter of 0.1 to 2.0 μm.
[2] The porous resin particles according to [1], which have a median diameter of 3.0 to 150 μm.
[3] A method for producing porous resin particles, comprising the following steps (a) to (d).
(a) W/O (inner water phase/ Oil phase) step of obtaining a type emulsion.
(b) W/O/W (inner water phase/oil phase/outer water phase) comprising the W/O emulsion obtained in (a) above and an outer water phase component containing a dispersion stabilizer for suspension polymerization Obtaining a type emulsion.
(c) a step of polymerizing a monomer in the W/O/W emulsion obtained in (b) above to obtain an aqueous polymer dispersion;
(d) a step of removing the external aqueous phase and water inside the polymer from the aqueous polymer dispersion obtained in (c) above;
[4] A personal care product comprising the porous resin particles according to either [1] or [2].
[5] A heat insulating material comprising the porous resin particles according to any one of [1] and [2].
[6] A sound insulating material comprising the porous resin particles according to any one of [1] and [2].

Since the porous resin particles of the present invention have a large pore volume, they have excellent liquid absorbing performance. The porous resin particles of the present invention having such performance can be used to absorb excessive sebum such as cosmetics (foundation, sunscreen, etc.) and sebum removing products (sebum absorbing powder, oil removing paper, oil removing handkerchief, etc.). It can be suitably used as an additive for required personal care products. In addition, since the porous resin particles of the present invention have relatively large cavities in the particles, they can be suitably used as a constituent component of heat insulating materials and sound insulating materials.

2 is a SEM photograph showing the appearance of the porous resin particles of the present invention obtained in Example 1. FIG. 1 is an SEM photograph showing a cross section of the porous resin particles of the present invention obtained in Example 1. FIG.

The present invention will be described in detail below. The porous resin particles of the present invention are particles made of resin, and have communicating pores extending from the surface to the inside. There are no particular restrictions on the resin used as the material, and examples include polyethylene, polypropylene, polyvinyl chloride, ABS resin, polystyrene, (meth)acrylic resin, polyacrylonitrile, polyvinyl alcohol, polyamide, polyacetal, polycarbonate, polyester, polyurethane, epoxy resin, Styrene-butadiene rubber, chloroprene rubber, and the like can be used.

The cumulative pore volume of the porous resin particles of the present invention has a lower limit of 1.5 ml/g, preferably 2.0 ml/g, more preferably 2.5 ml/g. The upper limit is 5.0 ml/g, preferably 4.0 ml/g, more preferably 3.5 ml/g. If the cumulative pore volume is too small, the area into which the liquid or the like can permeate becomes small, resulting in a decrease in absorption. If the cumulative pore volume is too large, the strength will decrease and the material will easily collapse, making it unsuitable for practical use.

Furthermore, the lower limit of the average pore diameter of the porous resin particles of the present invention is 0.1 μm, preferably 0.2 μm, more preferably 0.3 μm. The upper limit is 2.0 μm, preferably 1.5 μm, and preferably 1.0 μm. If the average pore diameter is too small, attempts to secure the cumulative pore volume within the range described above will result in a reduction in the thickness of the inner walls of the pores, resulting in brittle particles that may not be able to maintain their shape. On the other hand, when the average pore diameter is too large, the particle shape cannot maintain a spherical shape, resulting in an irregular shape, which may deteriorate the texture.

The lower limit of the median diameter of the porous resin particles of the present invention is preferably 3.0 μm, more preferably 5.0 μm. The upper limit is preferably 150 μm, more preferably 100 μm, even more preferably 50 μm, and most preferably 30 μm. Within this numerical range, it is easy to achieve both a sufficient absorption amount of sebum and good texture and light diffusibility when added to cosmetics and the like. On the other hand, if it exceeds 150 μm, it becomes difficult to prepare by suspension polymerization. Here, the median diameter refers to the particle diameter at which the integrated value is 50% in the volume-based particle diameter distribution obtained for a certain powder.

The porous resin particles of the present invention described above can exhibit an oil absorption of 125 ml/100 g or more, preferably 150 ml/100 g or more, more preferably 180 ml/100 g, as measured by the method described later. However, the upper limit is preferably 400 ml/100 g, more preferably 300 ml/100 g, from the viewpoint of preventing re-release of the absorbed liquid.

The cumulative pore specific surface area of the porous resin particles of the present invention is not particularly limited, but is generally 10 m ² /g to 100 m ² /g as a result of satisfying the above-mentioned characteristics.

The porous resin particles of the present invention described above are preferably produced by a method including the following steps (a) to (d).
(a) W/O (inner water phase/oil phase ) type emulsion.
(b) W/O/W (inner water phase/oil phase/outer water phase) comprising the W/O emulsion obtained in (a) above and an outer water phase component containing a dispersion stabilizer for suspension polymerization Obtaining a type emulsion.
(c) a step of polymerizing a monomer in the W/O/W emulsion obtained in (b) above to obtain an aqueous polymer dispersion;
(d) removing the external phase and the water inside the polymer from the aqueous polymer dispersion obtained in (c) above;

The inner water phase in the above step (a) is obtained by dissolving any of polyethyleneimine, polyallylamine or sodium polyacrylate in water. These additives have a role as a water-soluble dispersant for dispersing the internal water phase in the oil phase, and the lower limit of the additive amount is preferably 1.5% by weight based on the weight of the monomer. 0% by weight is more preferred. Moreover, as an upper limit, 5.0 weight% is preferable.

The oil phase in the above step (a) is obtained by dissolving a polymerization initiator and ethyl cellulose in a hydrophobic monomer. The hydrophobic monomer is not particularly limited as long as particles can be formed by polymerization. Examples include styrene-based monomers such as styrene, p-methylstyrene and p-chlorostyrene; methyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate. , lauryl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, etc.; methacrylate monomers, such as methyl methacrylate, lauryl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl vinyl ether, ethyl vinyl ether Alkyl vinyl ethers such as; vinyl ester monomers such as vinyl acetate and vinyl butyrate; diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, hexaethylene glycol di(meth)acrylate polyethylene glycol di(meth)acrylate; ethylene glycol di(meth)acrylate, divinylbenzene, trimethylolbrobane tri(meth)acrylate, etc.; You can choose and use them in combination.

The polymerization initiator in step (a) is not particularly limited as long as it dissolves in the above hydrophobic monomer and can initiate radical polymerization. Examples include methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, Examples include peroxides such as dilauroyl peroxide and t-hexylperoxy-2-ethylhexanoate, and azo compounds such as 2,2′-azobis(2,4-dimethylvaleronitrile). The lower limit of the amount added to the oil phase is preferably 0.1% by weight, and the upper limit is preferably 2.0% by weight based on the weight of the monomer.

Ethyl cellulose in the step (a) plays a role in stabilizing the dispersion of the inner water phase. The lower limit of the amount added is preferably 0.1% by weight, and the upper limit is preferably 2.0% by weight based on the weight of the monomer.

The W/O (inner water phase/oil phase) emulsion in step (a) is obtained by adding the inner water phase to the oil phase and suspending them. Here, the amount of the inner water phase to be added to the weight of the oil phase is preferably 20% by weight as a lower limit and 75% by weight as an upper limit.

The suspension method in the step (a) may be carried out using a known method and apparatus. Examples thereof include a method of dispersing using a mechanical dispersing machine such as a homomixer and a biomixer, an ultrasonic homogenizer, and the like.

Next, the external aqueous phase in the step (b) is obtained by adding and dissolving a dispersion stabilizer for suspension polymerization in water. The dispersion stabilizer may be selected from known ones, examples of which include water-soluble polymeric dispersants such as polyvinyl alcohol, polyvinylpyrrolidone, cellulose, gelatin, sodium polyacrylate and sodium polymethacrylate; sodium lauryl sulfate; Anionic surfactants such as polyoxyethylene alkylphenyl ether sulfate (e.g., polyoxyethylene distyrylphenyl ether sulfate ammonium); cationic surfactants such as alkylamine salts and quaternary ammonium salts; lauryl dimethyl zwitterionic surfactants such as amine oxide; nonionic surfactants such as polyoxyethylene alkyl ether; other alginate, zein, casein; barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, calcium phosphate, talc, clay, Inorganic dispersants such as diatomaceous earth, bentonite, titanium hydroxide, thorium hydroxide, and metal oxide powders can be used. These may use only 1 type and may use 2 or more types together. As the dispersant, it is preferable to use a water-soluble polymer-based dispersant. The lower limit of the amount of the dispersant used is preferably 0.5% by weight, and the upper limit is preferably 5.0% by weight.

The W/O/W (inner water phase/oil phase/outer water phase) emulsion in the step (b) is obtained by adding the W/O emulsion prepared in the step (a) to the outer water phase and suspending it. is obtained by Here, the amount of the W/O type emulsion added is preferably such that the weight ratio of the monomer to the total weight of the obtained W/O/W type emulsion is in the range of 10 to 40% by weight.

The suspending method in step (b) can employ the same method as in step (a) described above.

Next, the aqueous polymer dispersion in step (c) is obtained by polymerizing the monomers in the W/O/W emulsion prepared in step (b). Here, polymerization conditions are not particularly limited, and various conditions such as polymerization temperature and polymerization time may be set according to the types of monomers and additives used. For example, the polymerization temperature and polymerization time can be determined according to the 10-hour half-life temperature of the polymerization initiator.

Next, the method for removing water in step (d) is not particularly limited, and a known method may be used. Examples include a method of removing water through suction filtration, washing with water, and heat drying.

The porous resin particles of the present invention described above have excellent oil absorbency and can be suitably used as additives for cosmetics such as foundations and sunscreens. In addition, since the porous resin particles of the present invention have relatively large cavities in the particles, they can be suitably used as a constituent component of heat insulating materials and sound insulating materials.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples. The measurement methods used for evaluation in the examples are as follows.

(1) Median diameter A dried sample is soaked in a surfactant and then dispersed in water to prepare a dispersion. Using SALD-200V, a laser diffraction particle size distribution analyzer manufactured by Shimadzu Corporation, the particle size distribution of the sample particles was measured, and the median diameter was obtained from the obtained particle size distribution.

(2) Cumulative pore volume, average pore diameter, and cumulative pore specific surface area The sample was dried at a constant temperature of 120 ° C. for 4 hours, and then the pore distribution with a pore diameter of about 0.0036 μm to 200 μm was measured by mercury porosimetry. . The pore diameter was calculated from the washburn equation, and the measurement conditions and measurement apparatus were as follows.
Measurement conditions ・Surface tension of mercury: 480 dynes/cm
・Contact angle between mercury and sample: 140 degrees
Measuring device Autopore V9620 (manufactured by Micromeritics)

(3) Oil absorption Measured according to JIS K5101-13-2:2004.

Example 1
(a) Step: Preparation of W/O (internal water phase/oil phase) type emulsion Dilauroyl peroxide and ethyl cellulose were added to a monomer mixture in which methyl methacrylate and ethylene glycol dimethacrylate were mixed at a weight ratio of 90:10. were added in an amount of 0.4% by weight and 1.0% by weight relative to the weight of the monomer mixture and dissolved to obtain an oil phase. After mixing such an oil phase and an inner water phase obtained by adding polyethyleneimine to water in an amount of 3.0% by weight based on the weight of the monomer mixture, the inner water phase is formed in the oil phase by stirring with a homomixer. A W/O (aqueous phase/oil phase) type emulsion in which droplets of are dispersed was obtained.

(b) Step: Preparation of W/O/W (inner water phase/oil phase/outer water phase) emulsion After mixing an external aqueous phase obtained by adding 2.0% by weight of polyvinyl alcohol to water so that the weight ratio of the monomer mixture to the total weight of the resulting W/O/W emulsion is 20% by weight, A W/O/W emulsion was obtained by stirring with a homomixer.

Steps (c) and (d): Preparation of Porous Resin Particles The W/O/W emulsion obtained in step (b) above was heated to 70° C. and allowed to react for 4 hours. After the obtained slurry was filtered under reduced pressure, the filtered solid matter was washed with water and dried to obtain porous resin particles of Example 1. A SEM photograph of the appearance of the obtained particles is shown in FIG. 1, and an SEM photograph of the cross section of the particles is shown in FIG. From FIG. 2, it can be seen that there are further holes on the far side of the hole cross section, and the holes communicate with each other. The microparticles seen on the surface and inside the pores in FIG. 1 are contamination. FIG. 2 is a photograph taken by cutting the particles hardened with resin.

Example 2
Porous resin particles of Example 2 were obtained in the same manner as in Example 1, except that the amount of polyethyleneimine added in the step (a) was changed to 2.3% by weight.

Example 3
Porous resin particles of Example 3 were obtained in the same manner as in Example 1, except that the amount of polyethyleneimine added in the step (a) was changed to 1.5% by weight.

Comparative example 1
In step (a) of Example 1, an attempt was made to prepare a W/O emulsion without adding ethyl cellulose, but the oil phase and internal water phase were separated, and the desired porous resin particles could not be obtained. rice field.

Comparative example 2
In step (a) of Example 1, an attempt was made to prepare a W/O emulsion without adding polyethylenimine, but the oil phase and internal water phase were separated, and the desired porous resin particles could not be obtained. I didn't.

Comparative example 3
As Comparative Example 3, commercially available acrylic porous resin particles (cumulative pore volume: 1.31 ml/g, median diameter: 8 μm) were used.

The porous resin particles of Examples 1, 2, 3 and Comparative Example 3 were measured by the method described above, and the results are shown in Table 1.

From Table 1, it can be seen that the porous resin particles of Examples 1, 2 and 3 have higher oil absorption than Comparative Example 3, and that Example 1 in particular has excellent oil absorption capacity.

Claims (6)

Porous resin particles having a cumulative pore volume of 1.5 to 5.0 ml/g and an average pore diameter of 0.1 to 2.0 μm. 2. The porous resin particles according to claim 1, which have a median diameter of 3.0 to 150 μm. A method for producing porous resin particles, comprising the following steps (a) to (d).
(a) W/O (inner water phase/ Oil phase) step of obtaining a type emulsion.
(b) W/O/W (inner water phase/oil phase/outer water phase) comprising the W/O emulsion obtained in (a) above and an outer water phase component containing a dispersion stabilizer for suspension polymerization Obtaining a type emulsion.
(c) a step of polymerizing a monomer in the W/O/W emulsion obtained in (b) above to obtain an aqueous polymer dispersion;
(d) a step of removing the external aqueous phase and water inside the polymer from the aqueous polymer dispersion obtained in (c) above; A personal care product comprising the porous resin particles according to claim 1 or 2. A heat insulating material comprising the porous resin particles according to claim 1 . A sound insulating material comprising the porous resin particles according to claim 1 or 2.

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