JP6520722B2 - Vinyl polymer particles and composition containing the particles - Google Patents

Description

The present invention relates to vinyl polymer particles, resin molded articles containing the particles, and various compositions.

Heretofore, several types of resin particles having hygroscopicity have been proposed. For example, Patent Document 1 discloses a crosslinked acrylonitrile polymer fine particle having a nitrogen content increase of 1.0 to 15.0% by weight due to hydrazine crosslinking, and a salt type carboxyl group of 1.0 mmol / g or more is introduced. No. 6,057,095, discloses high moisture absorbing and releasing fine particles characterized in that However, the use thereof is limited because the particles have a deep pink color derived from a hydrazine crosslinking structure.

Patent Literature 2 also has a moisture absorbing and releasing property that is a vinyl polymer having a crosslinked structure obtained by copolymerizing divinylbenzene, which contains 1.0 to 8.0 meq / g of a potassium salt type carboxyl group. Polymers are disclosed. However, divinylbenzene has a strong odor, a low polymerization rate, and takes time to remove residual monomers, which causes problems in production.

Further, Patent Document 3 discloses moisturizing particles obtained by hydrolyzing a carboxylic acid ester on the surface of crosslinked polyacrylic acid ester particles. However, in order to obtain the particles, the hydrolysis step has to be carried out in a mixed solvent of an aqueous alkaline solution and an organic solvent, and furthermore, in order to obtain a dry state, with an organic solvent such as methanol or diethyl ether. It is necessary to use an organic solvent in the production process, for example, water must be replaced and then dried, which causes problems in terms of process complexity and environmental load. In addition, there are many cracks on the surface of the particles, and there is a possibility that the surface layer portion may collapse and be pulverized at the time of drying.

Japanese Patent Application Publication No. 08-225610 JP, 2009-074098, A JP, 2011-126979, A

As described above, the conventional moisture absorbent / desorbable particles have problems in applications, production processes, durability, and the like. The present invention has been made in view of the current state of the prior art, and the purpose thereof is a moisture absorbing and releasing property which can be made into any color, is easy to produce, and is not pulverized even by drying etc. It is an object of the present invention to provide particles, resin molded articles containing the particles, and various compositions.

That is, the above object of the present invention is achieved by the following means.
(1) having a carboxyl group 1~10mmol / g, and a vinyl polymer spherical particles comprising an ester-based crosslinking agent and no ester structure ether-based crosslinking agent as a copolymerization component, the ester The vinyl-based heavy-duty characterized in that the copolymerization ratio of the crosslinking agent is 5 to 30% by weight, and the copolymerization ratio of the ether-based crosslinking agent not having the ester structure is 0.01 to 10% by weight. Coalesced particles .

( 2 ) The vinyl polymer particle according to (1), which contains a microparticulate additive inside the particle.
( 3 ) The vinyl polymer particle according to (1) or ( 2 ), wherein the water swelling degree value represented by the following formula is 1 to 3.
Formula: [water swelling degree] = X / Y
here,
X: Put 1 g of particles into a 16.5 mm diameter test tube, then add water to a 10 ml mark and place the test tube upright with the height from the bottom of the test tube to the top of the sedimented particles Y: Put 1 g of particles into a 16.5 mm diameter test tube, then add methyl ethyl ketone to a 10 ml mark and place the test tube upright with the height from the bottom of the test tube to the top of the sedimented particles

( 4 ) Resin molded object containing vinyl polymer particle in any one of (1)-( 3 ).
( 5 ) Coating composition containing vinyl polymer particles according to any one of (1) to ( 3 ).
( 6 ) An ink composition containing the vinyl polymer particles according to any one of (1) to ( 3 ).
( 7 ) A fiber structure containing the vinyl polymer particles according to any one of (1) to ( 3 ).

The vinyl polymer particles of the present invention can easily contain various additives in the inside of the particles while having excellent moisture absorption and release performance and the like. It is possible to have moisture absorbing and releasing particles having a color. The vinyl polymer particles of the present invention absorb and release, for example, synthetic leathers where appearance is important, resin molded articles such as films, compositions such as paints and inks, and fiber structures such as non-woven fabrics, paper, and fabrics. It can be used as a moisturizing agent.

3 is a SEM photograph of vinyl polymer particles of Example 1.

The vinyl polymer particles of the present invention have carboxyl groups. The carboxyl group is a polar group having high hydrophilicity, and the moisture absorption and release of the vinyl polymer particle of the present invention is expressed by containing the group. In particular, when the counter ion of the carboxyl group is an ion other than a hydrogen ion (hereinafter, such a carboxyl group is referred to as a salt type carboxyl group), it is possible to exhibit excellent moisture absorption and release.

The salt type of such a salt type carboxyl group, that is, as a counter cation, for example, an alkali metal such as Li, Na, K, Rb and Cs, an alkaline earth metal such as Be, Mg, Ca, Sr and Ba, Cu, Other metals such as Zn, Al, Mn, Ag, Fe, Co, Ni, etc., NH ₄ , amines and the like can be mentioned. Among them, Na, K, Mg, Ca, Zn, Al, Ag, NH _{4 and the} like are preferable from the viewpoint of higher moisture absorbability, ease of use, safety and the like.

On the other hand, even when the counter cation of the carboxyl group is a hydrogen ion (hereinafter referred to as H-type carboxyl group), it is possible to exhibit moisture absorption and release although not as much as a salt type carboxyl group. Furthermore, excellent performance can be exhibited with regard to the adsorptivity, antiviral property, anti-allergenic property and the like of basic substances such as ammonia and organic amine compounds.

In the present invention, the various carboxyl groups described above may be mixed, and can be combined appropriately according to the required performance.

The amount of carboxyl groups in the vinyl polymer particles of the present invention is preferably 1 to 10 mmol / g, more preferably 3 to 9 mmol / g, and still more preferably 5 to 8 mmol / g. When the amount of carboxyl groups exceeds 10 mmol / g, the ratio of the crosslinked structure to be described later becomes too small to be close to a highly water-absorbent resin, sticky by moisture absorption, the volume change by water swelling becomes severe, etc. A problem arises. On the other hand, the lower the carboxyl group content, the lower the moisture absorption and release properties. In particular, when the content is less than 1 mmol / g, sufficient moisture absorption and release performance can not often be obtained.

As a method of introducing a carboxyl group into a vinyl polymer particle, a polymer particle obtained by using a monomer having a structure convertible to a carboxyl group by chemical modification such as hydrolysis as a copolymerization component, There is a method of introducing a carboxyl group by chemical modification and then converting it to a carboxyl group having a desired counter ion.

As a monomer having a structure capable of obtaining a carboxyl group by hydrolysis treatment, a monomer having a cyano group such as acrylonitrile and methacrylonitrile; acrylic acid, methacrylic acid, maleic acid, itaconic acid, vinyl propionic acid and the like Anhydrides and derivatives thereof, such as methyl (meth) acrylate, ethyl (meth) acrylate, normal propyl (meth) acrylate, isopropyl (meth) acrylate, normal butyl (meth) acrylate, (meth) Ester compounds such as normal octyl acrylate, 2-ethylhexyl (meth) acrylate, hydroxyl ethyl (meth) acrylate, (meth) acrylamide, dimethyl (meth) acrylamide, monoethyl (meth) acrylamide, normal-t-butyl (meth) ) Amide such as acrylamide Etc. can be illustrated.

Further, as a method of converting the carboxyl group into a desired salt form, the obtained polymer particles may be subjected to alkali metal ions such as Li, Na, K, Rb and Cs, and alkali earth ions such as Be, Mg, Ca, Sr and Ba. Acids and solutions containing a large amount of desired counter ions such as metal ions of other metals such as Cu, Zn, Al, Mn, Ag, Co, Ni, etc., organic cations such as NH ₄ , amines etc. It is possible to cite a method of performing ion exchange by acting.

Further, the vinyl polymer particles of the present invention are obtained by copolymerizing an ester-based crosslinking agent and an ether-based crosslinking agent to introduce a crosslinked structure. As described above, since the vinyl polymer particles of the present invention contain a large amount of carboxyl groups having a high affinity for water, they are tacky or swelled in water by being in contact with water. May be dissolved in water, and when such particles are blended in a resin or the like, the properties may be adversely affected. The crosslinked structure is intended to prevent such problems.

The ester crosslinker employed in the present invention is one having an ester structure and two or more, preferably three or more double bonds. As this ester type crosslinking agent, di (meth) acrylates, tri (meth) acrylates, tetra (meth) acrylates, hexa (meth) acrylates etc. can be mentioned. Here, the expression of (meth) acrylate represents both of methacrylate and acrylate.

Specifically, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, ethoxylated Bisphenol A di (meth) acrylate, propoxylated bisphenol A di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di ( Meta) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylol Ropantetora (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, and the like can be exemplified dipentaerythritol hexa (meth) acrylate.

In addition, the ether crosslinking agent employed in the present invention is one having an ether bond and two or more, more preferably three or more double bonds, and not having an ester structure. As this ether type crosslinking agent, allyl ether, allyl vinyl ether, vinyl ether etc. are mentioned. Among these, those having three or more double bonds are more preferable. Specifically, diallyl ether, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, allyl vinyl ether, 1,4-butanediol divinyl ether, cyclohexane dimethanol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, etc. are exemplified. can do.

In the present invention, it is necessary to use both the ester-based crosslinking agent and the ether-based crosslinking agent described above. When only an ester-based crosslinking agent is used, the particles are gelled in the hydrolysis described later, and it takes much time for dehydration and drying thereafter. In addition, the particles coalesce after drying, and it takes a lot of time in crushing and the like, and the particle shape is easily lost. It is considered that this is because most of the ester structure of the ester-based crosslinking agent is decomposed by the hydrolysis to reduce the number of crosslinked structures.

When only an ether crosslinking agent is used, it does not take as much time as in the case of using only the above-mentioned ester crosslinking agent in dehydration and drying after hydrolysis described later. However, since it swells violently when it absorbs water again, in the resin molded body etc. which added the said particle | grains, problems, such as a shape deform | transforming at the time of water wet etc. and a weak gel falling off, arise.

On the other hand, when both of the ester-based crosslinking agent and the ether-based crosslinking agent described above are used, dehydration can be easily performed without gelation after hydrolysis, and spherical particles can be obtained. In addition, since the obtained particles are suppressed from swelling even when they are wet with water, the above-mentioned problems hardly occur.

In order to obtain such an advantageous effect when using both an ester crosslinking agent and an ether crosslinking agent, the copolymerization ratio of the ester crosslinking agent is preferably 5 to 30% by weight, more preferably 10 to 30% by weight. Moreover, as a copolymerization ratio of the ether type crosslinking agent which does not have ester structure, Preferably it is 0.01 to 10 weight%, More preferably, it is 0.5 to 5 weight%.

The vinyl polymer particles of the present invention have a spherical shape. Specifically, the circularity measured by the method described later is 0.90 or more, more preferably 0.95 or more. The spherical shape makes it difficult for the particles to be broken or chipped due to stirring or the like at the time of mixing with a resin or the like, and micronization can be suppressed. It can be carried out.

Moreover, as a water swelling degree of the vinyl-type polymer particle of this invention, the numerical value measured by the method mentioned later becomes like this. Preferably it is 1-3, More preferably, it is 1.5-3. When the degree of water swelling exceeds 3, the volume change of particles during drying and moisture absorption becomes excessive, and when used as an additive for a resin molded product, deformation or deterioration of the resin molded product is promoted, or resin It becomes easy to produce problems, such as particle | grain fall-off from a molding. On the other hand, when the degree of water swelling is less than 1, the amount of moisture absorption may be excessively limited, and sufficient moisture absorption / desorption performance may not be obtained. The degree of water swelling can be controlled by adjusting the amount of carboxyl groups in the vinyl polymer particles, the type of counter ion, the copolymerization ratio of the crosslinking agent, and the like.

In addition, the vinyl polymer particles of the present invention can be produced through suspension polymerization as described later. In suspension polymerization, polymerization is carried out by dispersing monomer droplets in a medium, but in the present invention, by adding an additive to the monomer droplets and polymerizing, other functions such as the above-mentioned moisture absorption and release performance, etc. , It is possible to add various functions. Such additives include various ones such as preservatives, fungicides, antibacterial agents, antioxidants, ultraviolet absorbers, pigments, fragrances, deodorants, adsorbents, inorganic hygroscopic agents, photocatalyst particles, etc. It is preferable that the function is maintained even after the hydrolysis treatment. Needless to say, a plurality of additives may be used.

Among them, when a pigment is added to the vinyl polymer particles of the present invention, moisture absorbing and releasing particles having a desired color can be obtained. Such moisture absorbing and releasing particles absorb and release the appearance without giving a sense of incongruity to the appearance, such as synthetic leather, resin molded articles such as films, compositions such as paints and inks, non-woven fabrics, paper, fabrics, etc. It is extremely useful because it can impart moisture.

Examples of the pigment that can be employed include natural pigments, fluorescent pigments, inorganic pigments, azo pigments, organic pigments such as polycyclic pigments, and the like. Among these, as inorganic pigments, zinc flower, lead white, lithopone, titanium dioxide, precipitated barium sulfate, barite powder, red lead, iron oxide red, yellow lead, zinc yellow, ultramarine blue, Prussia blue, carbon black, Titanium black etc. are mentioned. In addition, as azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments and the like can be mentioned, and as polycyclic pigments, phthalocyanine pigments, perylenes and perinone pigments, thioindigo pigments, quinacridones Pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments and the like. In addition, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments and the like can also be mentioned as pigments.

The addition amount of such an additive is not particularly limited and can be set so as to achieve a desired function, but in the case of a pigment, for example, sufficient color development can be obtained and stably. From the viewpoint of polymerization, it is desirable to use in the range of preferably 0.1 to 5% by weight, more preferably 0.4 to 3% by weight, based on the weight of the polymer constituting the vinyl polymer particles.

The average particle diameter of the vinyl polymer particles of the present invention is preferably 1 to 500 μm, more preferably 5 to 150 μm. If the average particle size exceeds 500 μm, molding defects are likely to occur when added to a resin for molding, etc. Even if molding can be performed, surface irregularities are severe and appearance defects occur, or particles fall off during use, etc. May cause problems. On the other hand, it is difficult in suspension polymerization to be less than 1 μm.

In addition, when the vinyl polymer particles of the present invention described above are used for the purpose of imparting moisture absorption / desorption performance to a resin molding or the like, the saturated moisture absorption rate of the particles under 20 ° C. × 65% RH conditions is Preferably, it is 15% or more, more preferably 20% or more, and still more preferably 30% or more. The saturated moisture absorption rate can be adjusted mainly by changing the amount of salt-type carboxyl groups in particles.

Examples of the method for producing vinyl polymer particles of the present invention include a method of hydrolyzing particles obtained by the suspension polymerization method. Specifically, first, a monomer having a structure that can be converted to a carboxyl group by the above-described chemical modification, an ester-based crosslinking agent, an ether-based crosslinking agent that does not have an ester structure, a polymerization initiator, and, if necessary A monomer mixture obtained by mixing the above-described additive and other vinyl monomer is dispersed as droplets in an aqueous medium, and the mixture is heated for polymerization to obtain raw material particles.

Next, the raw material particles are hydrolyzed in an alkaline compound solution, a mineral acid solution or an organic acid solution, and then, if necessary, a solution containing a large amount of a desired counter ion or an acid is allowed to act for ion exchange. It can be manufactured by carrying out. Here, examples of the alkaline compound used for hydrolysis include alkali metal hydroxides, ammonia and the like, mineral acids such as nitric acid, sulfuric acid and hydrochloric acid, and organic acids such as formic acid and acetic acid.

The vinyl polymer particles of the present invention obtained as described above can be incorporated into various materials and compositions such as resin moldings, coating compositions, ink compositions, fiber structures, etc. The substance can be provided with functions such as moisture absorption / desorption property, odor elimination property, basic substance adsorption property, antiviral property, or antiallergenic property. In particular, since the vinyl polymer particles of the present invention can be colored to any color by the pigment, they can be suitably used in materials and compositions that place importance on color.

Examples of the resin molded product of the present invention include fibers, synthetic leather, artificial leather, films, sheets and the like. For example, in the case of fibers, the vinyl polymer particles of the present invention are mixed with a spinning solution prepared by dissolving a urethane resin in dimethylacetamide or a spinning solution prepared by dissolving an acrylonitrile polymer in a sodium thiocyanate aqueous solution. By processing into a fiber form by a conventional spinning method, urethane fibers and acrylic fibers having moisture absorption and release performance can be produced.

In the case of artificial leather, the vinyl polymer particles of the present invention are mixed with a liquid in which a urethane resin is dissolved in dimethylformamide, and then coated on a non-woven fabric composed of polyester fibers, and then removed in an aqueous solution. A solvent and drying can produce an artificial leather having moisture absorption and release performance.

Examples of the fiber structure of the present invention include yarn, knitted fabric, woven fabric, non-woven fabric, paper and the like. These can be produced using fibers containing the vinyl polymer particles of the present invention obtained as described above, and they can be produced as usual yarns, knits, wovens, wovens, non-wovens, papers, etc. It is also possible to produce by fixing vinyl polymer particles of

The addition amount of the vinyl polymer particles of the present invention in the materials and compositions as described above includes the target moisture absorption and release properties, deodorizing properties, basic substance adsorption properties, antiviral properties, or antiallergenic properties, etc. Although it can set suitably so that a function can be expressed, for example, in the case of a resin molding, it is preferable to set it as 5 to 60 weight% with respect to the weight of the whole resin molding. If it is less than 5% by weight, the properties of the vinyl polymer particles of the present invention may not be fully utilized, and if it exceeds 60% by weight, vinyl may be caused by deterioration of physical properties such as strength of the molded body or friction. Problems such as dropping of the polymer particles may occur.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples. In the examples, parts and percentages are by weight unless otherwise indicated. First, an evaluation method of each characteristic will be described.

(1) Degree of Circularity The degree of circularity in the present invention refers to the degree of circularity of particles calculated by the following equation.
Degree of circularity of particle projection image = (perimeter of circle having the same area as particle projection area) / (peripheral length of particle projection image)
Average value of circularity of particle projection image = circularity of particle, that is, circularity is 1 in the case of a perfect circle, and becomes smaller as the degree of irregular shape increases. The degree of circularity can be measured, for example, using a flow type particle image analyzer “FPIA-3000S” manufactured by Sysmex Corporation.

(2) An aqueous dispersion containing 5% of dewaterable sample particles was prepared, and the state when the aqueous dispersion was subjected to suction filtration was evaluated according to the following criteria.
○: The filtration is completed within 1 hour after the start of suction ×: The filtration is not completed even after 1 hour after the start of suction

(3) Carboxyl group weight The sample is dispersed in water and adjusted to pH 2.0 by addition of 1N hydrochloric acid. Then, the sample is separated by filtration, dried and the weight (W1 [g]) is measured. The weighed sample is redispersed in water and titrated with 0.1 N aqueous sodium hydroxide solution. From the titration curve obtained, the consumption amount (V [ml]) of the aqueous sodium hydroxide solution consumed for the carboxyl group is determined, and the carboxyl group amount is calculated by the following equation.
Amount of carboxyl group [mmol / g] = 0.1 × V / W1

(4) Water swelling degree 1 g of dried sample particles is placed in a test tube of 16.5 mm in diameter. Water is then added to a 10 ml mark to swell the particles. After leaving the test tube vertical for 60 hours, measure the height (X [cm]) from the bottom of the test tube to the top of the precipitated particles. On the other hand, measure the height (Y [cm]) from the bottom of the test tube to the top of the precipitated particles when swelling the sample particles in methyl ethyl ketone similarly to using methyl ethyl ketone instead of water. . From the measured values obtained, the degree of water swelling is calculated by the following equation.
Water swelling degree = X / Y

(5) Average particle size Measured with water as a dispersion medium using a laser diffraction type particle size distribution measuring apparatus "SALD-200V" manufactured by Shimadzu Corporation, and the average particle size (μm) was calculated from the particle size distribution represented on a volume basis. Ask.

(6) Saturated Moisture Absorption Rate of Particles About 5.0 g of a sample is dried at 105 ° C. for 16 hours, and the weight (W 2 [g]) is measured. Next, the sample is placed in a thermo-hygrostat kept at a temperature of 20 ° C. and a relative humidity of 65% for 24 hours. The weight (W3 [g]) of the sample absorbed in this manner is measured. From the above measurement results, it is calculated by the following equation.
Saturated moisture absorption rate [%] = (W3-W2) / W2 × 100

(7) Measure the weight (W4 [g]) by drying a square sample with a side of 10 cm of moisture absorption of the sheet at 105 ° C. for 16 hours. Next, the sample is placed in a thermo-hygrostat kept at a temperature of 20 ° C. and a relative humidity of 40% for 16 hours. The weight (W5 [g]) of the sample absorbed in this manner is measured. Next, the sample after measurement is placed in a constant temperature and humidity chamber adjusted to a temperature of 40 ° C. and a relative humidity of 90% for 2 hours, and then the weight of the sample (W6 [g]) is measured. From the above measurement results, the moisture absorption rate of the sheet under each condition is calculated by the following equation.
Moisture absorption rate [g / m ² ] = (W5-W4) /0.01 under temperature 20 ° C, relative humidity 40%
Moisture absorption rate [g / m ² ] = (W6-W4) /0.01 under temperature 40 ° C, relative humidity 90%

Example 1
A monomer mixture consisting of 82 parts of methyl acrylate, 17 parts of trimethylolpropane trimethacrylate, 1 part of pentaerythritol triallyl ether, 1 part of 2,2'-azobis (2,4-dimethylvaleronitrile), water 400 Disperse in parts. Next, polymerization is carried out at 50 ° C. for 2 hours, followed by washing with water and dehydration to obtain raw material particles. 150 parts of the raw material particles and 810 parts of water are mixed, 40 parts of sodium hydroxide is added, and hydrolysis is carried out at 95 ° C. for 10 hours, followed by washing with water, dehydration, drying and crushing, sodium salt type carboxyl Vinyl polymer particles of Example 1 having a group were obtained. The results of evaluating the properties of the particles are shown in Table 1. In addition, an SEM photograph of the particles is shown in FIG.

Comparative Example 1
A monomer mixture comprising 80 parts of methyl acrylate, 20 parts of trimethylolpropane trimethacrylate, and 1 part of 2,2'-azobis (2,4-dimethylvaleronitrile) instead of the monomer mixture in Example 1 The particles of Comparative Example 1 having a sodium salt type carboxyl group were obtained in the same manner as Example 1 except using. The results of evaluating the properties of the particles are shown in Table 1.

Comparative Example 2
Instead of the monomer mixture in Example 1, a monomer mixture consisting of 80 parts of methyl acrylate, 20 parts of pentaerythritol triallyl ether, and 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile) The particles of Comparative Example 2 having a sodium salt type carboxyl group were obtained in the same manner as Example 1 except for using. The results of evaluating the properties of the particles are shown in Table 1.

Example 2
Instead of the monomer mixture in Example 1, 80 parts of methyl acrylate, 19 parts of trimethylolpropane trimethacrylate, 1 part of pentaerythritol triarylether, 2,2'-azobis (2,4-dimethylvaleronitrile) In the same manner as in Example 1 except that a monomer mixture consisting of 1 part and 2 parts of carbon black was used, vinyl polymer particles of Example 2 having a sodium salt type carboxyl group were obtained. The results of evaluating the properties of the particles are shown in Table 1.

[Example 3]
Instead of the monomer mixture in Example 1, 85 parts of methyl acrylate, 10 parts of trimethylolpropane trimethacrylate, 5 parts of pentaerythritol triarylether, 2,2′-azobis (2,4-dimethylvaleronitrile) In the same manner as in Example 1 except that a monomer mixture consisting of 1 part was used, vinyl polymer particles of Example 3 having a sodium salt type carboxyl group were obtained. The results of evaluating the properties of the particles are shown in Table 1.

Example 4
Instead of the monomer mixture in Example 1, 69.5 parts of methyl acrylate, 30 parts of trimethylolpropane trimethacrylate, 0.5 parts of pentaerythritol triarylether, 2,2'-azobis (2,4-) A vinyl polymer particle of Example 4 having a sodium salt type carboxyl group was obtained in the same manner as Example 1 except that a monomer mixture consisting of 1 part of dimethylvaleronitrile) was used. The results of evaluating the properties of the particles are shown in Table 1.

As can be seen from Table 1, in Comparative Example 1 in which the ether crosslinking agent was not used and Comparative Example 2 in which the ester crosslinking agent was not used, the dewaterability was poor and the degree of water swelling was large. In Comparative Example 1, in particular, dehydration and hydrolysis after hydrolysis required much more time than the other examples. In Example 2, carbon black was added as a pigment, but the obtained particles exhibited good black color and had the same moisture absorption performance as Example 1 in which no pigment was added.

[Example 5]
67 parts of vinyl polymer particles of Example 2, 500 parts (solid content 20%) of urethane resin "Kurisbon NY-373" (manufactured by DIC Corporation), and 175 parts of dimethylformamide are mixed and coated on a release paper. Next, the coated release paper was immersed in water, desolvated, and dried to obtain a urethane resin sheet containing vinyl polymer particles of the present invention. The basis weight of the sheet was 145 g / m ² .

Further, when the sheet moisture absorption amount was measured according to the method described above, it was 14.9 g / m ² at a temperature of 20 ° C. and a relative humidity of 40%, and 47. at a temperature of 40 ° C. and a relative humidity of 90%. It was 8 g / m ² . On the other hand, the result of the same measurement of the amount of moisture absorption of a sheet prepared using only the urethane resin "Kurisbon NY-373" is 0.28 g / m ² at a temperature of 20 ° C and a relative humidity of 40%, and a temperature of 40 ° C The relative humidity was 90% and was 0.32 g / m ² . From the above, it is understood that a sheet having high hygroscopicity can be obtained by containing the vinyl polymer particles of the present invention. In addition, since the sheet has a large difference in the amount of moisture absorption under the low humidity atmosphere and the high humidity atmosphere, it is also used for humidity control such as releasing moisture absorbed under the high humidity atmosphere under the low humidity atmosphere. It is possible.

Claims (7)

A spherical vinyl polymer particle comprising, as a copolymer component, an ester-based crosslinking agent having 1 to 10 mmol / g of a carboxyl group and having no ester-based crosslinking agent and no ester structure , which is the ester-based crosslinking agent A vinyl-based polymer particle having a copolymerization ratio of 5 to 30% by weight and a copolymerization ratio of the ether-based crosslinking agent having no ester structure is 0.01 to 10% by weight . The vinyl polymer particle according to claim 1, wherein a microparticulate additive is contained inside the particle. The vinyl polymer particle according to claim 1 or 2, wherein the water swelling degree value represented by the following formula is 1 to 3.
Formula: [water swelling degree] = X / Y
here,
X: Put 1 g of particles into a 16.5 mm diameter test tube, then add water to a 10 ml mark and place the test tube upright with the height from the bottom of the test tube to the top of the sedimented particles Y: Put 1 g of particles into a 16.5 mm diameter test tube, then add methyl ethyl ketone to a 10 ml mark and place the test tube upright with the height from the bottom of the test tube to the top of the sedimented particles The resin molding containing the vinyl-type polymer particle in any one of Claims 1-3. A paint composition comprising the vinyl polymer particles according to any one of claims 1 to 3. An ink composition comprising the vinyl polymer particles according to any one of claims 1 to 3. The fiber structure containing the vinyl-type polymer particle in any one of Claims 1-3.

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