KR102191690B1 - Vinyl-based-polymer particles and composition containing said particles - Google Patents

Abstract

[Task] Conventional moisture-absorbing and desorptive particles are subject to special color, low polymerization rate, removal of residual monomers, use of organic solvents in the production process, drying by moisture absorption and desorption, micronization by shrinkage, etc., use, production process, durability, etc. Was to have. The present invention was invented in view of the phenomena of the prior art, and its object is that it is possible to have any color, and it is easy to produce, and moisture-absorbing and desorptive particles that are not pulverized even by drying, etc. It is to provide a resin molded article and various compositions.
[Solution means] Spherical vinyl polymer particles containing a carboxyl group and an ester crosslinking agent and an ether crosslinking agent not having an ester structure as a copolymerization component.

Description

Vinyl polymer particle and composition containing this particle {VINYL-BASED-POLYMER PARTICLES AND COMPOSITION CONTAINING SAID PARTICLES}

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

Conventionally, several things have been proposed as resin particles having hygroscopicity. For example, in Patent Document 1, a crosslinked acrylonitrile polymer fine particle having an increase in nitrogen content of 1.0 to 15.0 wt% due to hydrazine crosslinking, and a salt-type carboxyl group of 1.0 mmol/g or more is introduced. Is disclosed. However, since these particles have a dark pink color derived from a hydrazine crosslinked structure, their use is limited.

Further, Patent Document 2 discloses a moisture-absorbing and desorptive polymer, which is a vinyl polymer having a crosslinked structure obtained by copolymerizing a potassium salt-type carboxyl group from 1.0 to 8.0 meq/g and copolymerizing divinylbenzene. However, divinylbenzene has a problem in terms of production, such as a strong odor, a low polymerization rate, and difficult removal of residual monomers.

Further, Patent Document 3 discloses moisturizing particles obtained by hydrolyzing a carboxylic acid ester on the surface of a crosslinked polyacrylic acid ester particle. However, in order to obtain these particles, the hydrolysis step must be carried out in a mixed solvent of an aqueous alkali solution and an organic solvent, and in order to be dried, water is substituted with an organic solvent such as methanol or diethyl ether. After drying, an organic solvent must be used in the production process, and there is a problem in terms of process complexity and environmental load. In addition, there are many cracks on the surface of the particles, and there is a fear that the surface layer portion may collapse and become finely divided upon drying.

Japanese Unexamined Patent Application Publication No. Hei 08-225610 Japanese Unexamined Patent Publication No. 2009-074098 Japanese Unexamined Patent Publication No. 2011-126979

(Summary of the invention)

(Problems to be solved by the invention)

As described above, the conventional moisture-absorbing and desorptive particles have problems in use, production processes, and durability. The present invention was invented in view of the phenomena of the prior art, and its purpose is that it is possible to use any color, and it is easy to produce, and moisture-absorbing and desorptive particles that are not pulverized even by drying, etc. It is to provide a resin molded article and various compositions.

That is, the object of the present invention is achieved by the following means.

(1) Spherical vinyl polymer particles containing a carboxyl group and an ester crosslinking agent and an ether crosslinking agent not having an ester structure as a copolymerization component.

(2) The vinyl-based polymer particles according to (1), which have a carboxyl group of 1 to 10 mmol/g.

(3) The vinyl according to (1) or (2), characterized in that the copolymerization ratio of the ester-based crosslinking agent is 5 to 30% by weight, and the copolymerization ratio of the ether-based crosslinking agent not having an ester structure is 0.01 to 10% by weight. Based polymer particles.

(4) The vinyl-based polymer particles according to any one of (1) to (3), wherein the microparticle-like additive is contained inside the particles.

(5) The vinyl-based polymer particles according to any one of (1) to (4), wherein the value of the water swelling degree represented by the following formula is 1 to 3.

Formula: [water swelling degree]=X/Y

From here,

X: The height from the bottom of the test tube to the top of the settled particles after 1 g of particles are placed in a test tube with a diameter of 16.5 mm, water is then added to a scale of 10 ml, and the test tube is vertically set to stand still.

Y: The height from the bottom of the test tube to the top of the settled particles after 1 g of particles are placed in a test tube with a diameter of 16.5 mm, and then methyl ethyl ketone is added to a scale of 10 ml, and the test tube is made vertical and allowed to stand.

(6) A resin molded article containing the vinyl polymer particles according to any one of (1) to (5).

(7) A coating composition containing the vinyl polymer particles according to any one of (1) to (5).

(8) An ink composition containing the vinyl polymer particles according to any one of (1) to (5).

(9) A fiber structure containing the vinyl polymer particles according to any one of (1) to (5).

The vinyl polymer particles of the present invention have excellent moisture absorption and desorption performance, etc., and since it is easy to contain various additives inside the particles, for example, by containing a pigment, it is possible to obtain moisture absorption and desorption particles having an arbitrary color. Do. The vinyl-based polymer particles of the present invention are, for example, synthetic leathers, resin molded articles such as films, compositions such as paints and inks, non-woven fabrics, paper, fabrics, etc. Can be used as

1 is an SEM photograph of the vinyl polymer particles of Example 1. FIG.

(Form for carrying out the invention)

The vinyl polymer particles of the present invention have a carboxyl group. The carboxyl group is a polar group having high hydrophilicity, and by containing this group, the moisture absorption and desorption properties of the vinyl polymer particles of the present invention are expressed. 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 carboxyl group), it is possible to exhibit excellent moisture absorption and desorption properties.

Examples of the salt type of the salt-type carboxyl group, that is, counter cations, include alkali metals such as Li, Na, K, Rb, Cs, alkaline earth metals such as Be, Mg, Ca, Sr, Ba, Cu, Zn, Other metals such as Al, Mn, Ag, Fe, Co, and Ni, NH ₄ , and amines may be mentioned. Among them, Na, K, Mg, Ca, Zn, Al, Ag, NH ₄ and the like are preferable from the viewpoint of higher moisture absorption and desorption, ease of use, and safety.

On the other hand, even when the counter cation of the carboxyl group is a hydrogen ion (hereinafter, referred to as an H-type carboxyl group), the moisture absorption and desorption properties can be exhibited, although not as high as the salt carboxyl group. In addition, excellent performance can be exhibited for the adsorption, antiviral, or antiallergenic properties of basic substances such as ammonia and organic amine compounds.

In addition, in the present invention, it does not matter if various carboxyl groups described above are mixed, and can be appropriately combined according to the required performance.

The amount of the carboxyl group 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 group exceeds 10 mmol/g, the ratio of the crosslinked structure to be described later becomes too small, it becomes close to the superabsorbent polymer, and there is a problem such as adhesion due to moisture absorption, and a large volume change due to water swelling. Occurs. On the other hand, as the amount of carboxyl groups decreases, the moisture absorption and desorption property decreases. In particular, when the amount is less than 1 mmol/g, sufficient moisture absorption and desorption performance cannot be obtained in many cases.

As a method of introducing a carboxyl group into the vinyl polymer particles, a carboxyl group is introduced by chemical modification into the polymer particles obtained by using a monomer having a structure convertible to a carboxyl group by chemical modification such as hydrolysis as a copolymerization component, After that, a method of changing to a carboxyl group having a desired counter ion is mentioned.

Examples of the monomer having a structure capable of obtaining a carboxyl group upon hydrolysis treatment include a monomer having a cyano group such as acrylonitrile and methacrylonitrile; Anhydrides such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, and vinylpropionic acid, and derivatives thereof, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylate normal propyl, and iso(meth)acrylate. Ester compounds such as propyl, (meth)acrylate normal butyl, (meth)acrylate normal octyl, (meth)acrylate-2-ethylhexyl, hydroxylethyl(meth)acrylate, (meth)acrylamide, dimethyl(meth) Amides, such as acrylamide, monoethyl (meth)acrylamide, and normal-t-butyl (meth)acrylamide, etc. can be illustrated.

In addition, as a method of making the carboxyl group into a desired salt type, alkali metal ions such as Li, Na, K, Rb, Cs, alkaline earth metal ions such as Be, Mg, Ca, Sr, Ba, Cu, Zn, Al, etc. Other metal ions such as Mn, Ag, Fe, Co, Ni, and other metal ions such as NH ₄ and amines, such as a solution containing a large amount of desired counter ions such as organic cations, or a method of performing ion exchange by reacting an acid. have.

In addition, 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-based polymer particles of the present invention contain a large amount of carboxyl groups having high affinity with water, they become sticky by contact with water, swell violently in water, or in some cases dissolve in water. There is a possibility that such particles may be mixed with a resin or the like, and the properties may be adversely affected. The crosslinked structure is intended to prevent this problem from occurring.

The ester-based crosslinking agent employed in the present invention has an ester structure and two or more, preferably three or more double bonds. Examples of such ester crosslinking agents include di(meth)acrylates, tri(meth)acrylates, tetra(meth)acrylates, and hexa(meth)acrylates. Here, the notation of (meth)acrylate represents both 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(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tri Methylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra (Meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. can be illustrated.

In addition, the ether crosslinking agent employed in the present invention has an ether bond and two or more, more preferably three or more double bonds, and does not have an ester structure. Examples of such ether-based crosslinking agents include allyl ethers, allyl vinyl ethers, and vinyl ethers. Among these, it is more preferable to have 3 or more double bonds. Specifically, diallyl ether, trimethylolpropanediallyl ether, pentaerythritol triallyl ether, allyl vinyl ether, 1,4-butanedioldivinyl ether, cyclohexanedimethanol Divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, etc. can be illustrated.

In the present invention, it is necessary to use both the ester-based crosslinking agent and the ether-based crosslinking agent. When only an ester-based crosslinking agent is used, the particles are gelled by hydrolysis described later, and a lot of time is required for subsequent dehydration and drying. In addition, after drying, the particles are combined with each other, requiring a lot of time for disintegration or the like, and the shape of the particles is also easily damaged. This is considered to be due to the fact that most of the ester structure of the ester-based crosslinking agent is decomposed by hydrolysis and the number of crosslinked structures decreases.

Further, when only an ether-based crosslinking agent is used, dehydration and drying after hydrolysis described later do not require time as much as when only the ester-based crosslinking agent is used. However, when it is absorbed again, it swells violently, and therefore, in the resin molded body to which the particles are added, problems such as deformation of the shape of the resin molded body or the like when wet with water or the like, and the fragile gel dropping out occur.

On the other hand, when both the ester-based crosslinking agent and the ether-based crosslinking agent described above are used, gelation is not performed after hydrolysis, and dehydration can be easily performed, and spherical particles can be obtained. In addition, since the obtained particles are prevented from swelling even when wet with water, the above-described problem is unlikely to occur.

In order to obtain such advantageous effects when both an ester-based crosslinking agent and an ether-based crosslinking agent are used, the copolymerization ratio of the ester-based crosslinking agent is preferably 5 to 30% by weight, more preferably 10 to 30% by weight. In addition, the copolymerization ratio of the ether-based crosslinking agent having no ester structure is preferably 0.01 to 10% by weight, more preferably 0.5 to 5% by weight.

In addition, 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 particles to break or fall off due to agitation or the like when mixing with a resin or the like, and since micronization can be suppressed, a stable function can be imparted to a resin molded body or the like.

Further, as the degree of water swelling of the vinyl polymer particles of the present invention, the numerical value measured by the method described later is preferably 1 to 3, more preferably 1.5 to 3. When the degree of water swelling exceeds 3, the volume change of the particles during drying and during moisture absorption becomes excessive, and when used as an additive such as a resin molded body, deformation or deterioration of the resin molded body is accelerated, or particles from the resin molded body It becomes easy to cause problems such as dropout. On the other hand, when the water swelling degree is less than 1, the moisture absorption amount is excessively limited, and sufficient moisture absorption and desorption performance may not be obtained. This 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, it is possible to add various functions in addition to the above-described functions such as moisture absorption and desorption by polymerizing by containing an additive in the monomer droplet. Preservatives, fungicides, antibacterial agents, antioxidants, ultraviolet absorbers, pigments, fragrances, deodorants, adsorbents, inorganic absorbents, photocatalyst particles, etc. can be mentioned as such additives, but it is preferable that the function is maintained through hydrolysis treatment. Do. In addition, it goes without saying that a plurality of additives may be used.

Among them, when a pigment is added from the vinyl polymer particles of the present invention, moisture-absorbing and desorptive particles having a desired color can be obtained. These moisture-absorbing and desorptive particles are extremely useful because they can impart moisture-absorbing and desorption without discomfort in appearance in synthetic leathers, resin molded articles such as films, compositions such as paints and inks, non-woven fabrics, papers, textiles, etc. Do.

Examples of the pigments that can be employed include organic pigments such as natural pigments, fluorescent pigments, inorganic pigments, azo pigments, and polycyclic pigments. Among them, as inorganic pigments, zinc, lead white, lithopone, titanium dioxide, precipitated barium sulfate, burrite powder, brisket (gwangmyeong coal), iron oxide, sulfur lead, zinc sulfur, ultramarine blue, prussian blue, carbon black, titanium And black. In addition, examples of azo pigments include insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, etc., and polycyclic pigments include phthalocyanine pigments, perylene and perinone pigments, and thioindigo pigments. , Quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, and the like. In addition, dye lake pigments, azine pigments, nitroso pigments, nitro pigments and the like are also mentioned as pigments.

The amount of these additives to be added is not particularly limited and can be set so as to achieve a desired function. For example, in the case of a pigment, from the viewpoint of obtaining sufficient color development and stably polymerizing, vinyl polymer particles It is preferable to use in the range of preferably 0.1 to 5% by weight, and more preferably 0.4 to 3% by weight, based on the weight of the polymer constituting the.

In addition, 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 diameter exceeds 500 μm, molding defects are likely to occur during molding by adding to the resin. Even if molding can be performed, the surface irregularities become violent, and the particles fall off during use. There are cases that cause. On the other hand, it is difficult in suspension polymerization to be less than 1 μm.

In addition, when the vinyl-based polymer particles of the present invention described above are used for the purpose of imparting moisture absorption and desorption properties to a resin molded article, etc., the saturated moisture absorption rate of the particles under the condition of 20°C x 65% RH is preferably 15% or more It is preferably 20% or more, more preferably 30% or more. Such a saturated moisture absorption rate can be adjusted mainly by changing the amount of salt-type carboxyl groups in the particles or the like.

As a method for producing the vinyl polymer particles of the present invention, a method of hydrolyzing the particles obtained by the suspension polymerization method is exemplified. Specifically, first, a monomer having a structure convertible to a carboxyl group by the above-described chemical modification, an ester-based crosslinking agent, an ether-based crosslinking agent not having an ester structure, a polymerization initiator, and the above-described additives or other vinyl-based monomers as necessary. The monomer mixture obtained by mixing is made into droplets, dispersed in an aqueous medium, heated to perform polymerization, and raw material particles are obtained.

Subsequently, the raw material particles are hydrolyzed in an alkaline compound solution, an inorganic acid solution, or an organic acid solution, and then, if necessary, a solution or acid containing a large amount of desired counter ions is reacted to perform ion exchange. have. Here, examples of the alkaline compounds used for hydrolysis include alkali metal hydroxides and ammonia, examples of inorganic acids such as nitric acid, sulfuric acid and hydrochloric acid, and examples of organic acids including formic acid and acetic acid.

The vinyl-based polymer particles of the present invention obtained as described above are contained in various materials and compositions such as resin molded articles, paint compositions, ink compositions, and fiber structures, so that the material and composition have moisture absorption and desorption properties, deodorization properties, basic material adsorption properties, It can impart a function such as antiviral or antiallergenic. In particular, since the vinyl polymer particles of the present invention can be colored in any color with a pigment, they can be suitably used for materials and compositions that value color.

Examples of the resin molded article of the present invention include fibers, synthetic leather, artificial leather, films, and sheets. For example, in the case of fibers, the vinyl polymer particles of the present invention may be added to a spinning dope prepared by dissolving a urethane resin in dimethylacetamide or a spinning dope prepared by dissolving an acrylonitrile polymer in an aqueous sodium thiocyanate solution. Urethane fibers or acrylic fibers having moisture absorption and desorption properties can be produced by mixing and processing them into fibers by a conventional spinning method.

In the case of artificial leather, after mixing the vinyl-based polymer particles of the present invention in a liquid in which urethane resin is dissolved in dimethylformamide, coating is applied to a nonwoven fabric composed of polyester fibers, and thereafter, a solvent is removed in an aqueous solution. By drying, it is possible to manufacture an artificial leather having moisture absorption and desorption properties.

Examples of the fiber structure of the present invention include yarn, knitted fabric, woven fabric, nonwoven fabric, and paper. These can be produced using fibers containing the vinyl polymer particles of the present invention obtained as described above, and by fixing the vinyl polymer particles of the present invention to ordinary yarn, knitted fabric, woven fabric, nonwoven fabric, paper, etc. It is also possible to manufacture.

The amount of the vinyl polymer particles of the present invention added to the above-described materials or compositions is appropriate so that the desired functions such as moisture absorption and deodorization, deodorization, adsorption of basic substances, anti-viral or anti-allergenic properties can be expressed. Although it can be set, for example, in the case of a resin molded body, it is preferable to set it as 5 to 60 weight% with respect to the total weight of a resin molded object. If it is less than 5% by weight, the properties of the vinyl-based polymer particles of the present invention may not be utilized, and if it exceeds 60% by weight, the vinyl-based polymer particles are removed due to a decrease in physical properties such as strength of the molded body or friction. There are cases where such problems occur.

(Example)

Although the present invention is specifically described by the following examples, the present invention is not limited to the following examples. In addition, parts and percentages in the examples are expressed on a weight basis unless otherwise specified. First, the evaluation method of each characteristic is demonstrated.

(1) circularity

The circularity in the present invention refers to the circularity of the particles calculated by the following equation.

Circularity of the particle projection = (Circumference length of the circle with the same area as the particle projection area)/(Circumference length of the particle projection)

Average value of the circularity of the particle projection = circularity of the particle

That is, the circularity becomes 1 in the case of a perfect circle, and becomes a smaller value as the degree of irregularity increases. Such circularity can be measured using, for example, a flow-type particle image analyzer "FPIA-3000S" manufactured by Sysmatics.

(2) dehydration

An aqueous dispersion containing 5% of sample particles was prepared, and the state when the aqueous dispersion was suction-filtered was evaluated according to the following criteria.

○: Filtration is completed within 1 hour after the start of suction

×: Filtration is not completed even after 1 hour elapses after the start of suction

(3) Carboxyl skill

The sample is dispersed in water, and 1N hydrochloric acid is added to adjust the pH to 2.0. Subsequently, the sample is separated by filtration, dried, and the weight (W1 [g]) is measured. The sample after weighing is redispersed in water, and titration is performed with a 0.1N sodium hydroxide aqueous solution. From the obtained titration curve, the consumption amount (V[ml]) of sodium hydroxide aqueous solution consumed in the carboxyl group is calculated, and the amount of carboxyl group is calculated by the following equation.

Carboxyl skill [mmol/g]=0.1×V/W1

(4) Water swelling degree

Put 1g of dried sample particles into a test tube with a diameter of 16.5mm. Then, water is added to the scale of 10 ml, and this particle is swelled. After the test tube is vertical and allowed to stand for 60 hours, the height (X[cm]) from the bottom of the test tube to the top of the settled particles is measured. On the other hand, measure the height (Y[cm]) from the bottom of the test tube to the top of the settled particles when the sample particles are swelled in methyl ethyl ketone except for using methyl ethyl ketone instead of water. do. From the obtained measured value, the water swelling degree is calculated by the following equation.

Water swelling degree = X/Y

(5) Average particle diameter

Using a laser diffraction type particle size distribution measuring device "SALD-200V" manufactured by Shimadzu Sesakusho, it is measured using water as a dispersion medium, and the average particle diameter (µm) is obtained from the particle diameter distribution expressed on a volume basis.

(6) Saturation moisture absorption rate of particles

About 5.0 g of a sample is dried at 105° C. for 16 hours, and the weight (W2[g]) is measured. Next, this sample is placed in a thermo-hygrostat controlled at a temperature of 20°C and a relative humidity of 65% for 24 hours. In this way, the weight (W3[g]) of the sample absorbed is measured. From the above measurement results, it is calculated by the following equation.

Saturated moisture absorption [%] = (W3-W2)/W2×100

(7) moisture absorption of the sheet

A square sample with a side of 10 cm is dried at 105°C for 16 hours, and the weight (W4[g]) is measured. Next, this sample is placed in a thermo-hygrostat controlled at a temperature of 20°C and a relative humidity of 40% for 16 hours. In this way, the weight (W5[g]) of the sample absorbed is measured. Next, the measured sample is placed in a thermo-hygrostat controlled at a temperature of 40°C and a relative humidity of 90% for 2 hours, and 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 a temperature of 20℃ and a relative humidity of 40%

Moisture absorption rate [g/m ² ]=(W6-W4)/0.01 under a temperature of 40℃ and a relative humidity of 90%

[Example 1]

A monomer consisting of 82 parts of methyl acrylate, 17 parts of trimethylolpropane trimethacrylate, 1 part of pentaerythritol triallyl ether, and 1 part of 2,2'-azobis (2,4-dimethylvaleronitrile) The mixture is dispersed in 400 parts of water. Subsequently, polymerization is performed at 50° C. for 2 hours, washed with water, and dehydrated to obtain raw material particles. 150 parts of the raw material particles and 810 parts of water were mixed, 40 parts of sodium hydroxide were added, hydrolyzed at 95° C. for 10 hours, washed with water, dehydrated, dried, and pulverized to obtain a vinyl-based sodium salt-type carboxyl group. Polymer particles were obtained. Table 1 shows the results of evaluating the properties of these particles. Further, an SEM photograph of this particle is shown in Fig. 1.

[Comparative Example 1]

Instead of the monomer mixture in Example 1, a monomer consisting of 80 parts of methyl acrylate, 20 parts of trimethylolpropane trimethacrylate, and 1 part of 2,2'-azobis (2,4-dimethylvaleronitrile) In the same manner as in Example 1 except for using the mixture, particles of Comparative Example 1 having a sodium salt type carboxyl group were obtained. Table 1 shows the results of evaluating the properties of these particles.

[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) was prepared. Except for using, it carried out similarly to Example 1, and obtained the particle|grains of the comparative example 2 which has a sodium salt type carboxyl group. Table 1 shows the results of evaluating the properties of these particles.

[Example 2]

Instead of the monomer mixture in Example 1, 80 parts of methyl acrylate, 19 parts of trimethylolpropane trimethacrylate, 1 part of pentaerythritoltriallyl ether, 2,2'-azobis (2,4-di A vinyl polymer particle of Example 2 having a sodium salt carboxyl group was obtained in the same manner as in Example 1 except for using a monomer mixture consisting of 1 part of methylvaleronitrile) and 2 parts of carbon black. Table 1 shows the results of evaluating the properties of these particles.

[Example 3]

Instead of the monomer mixture in Example 1, 85 parts of methyl acrylate, 10 parts of trimethylolpropane trimethacrylate, 5 parts of pentaerythritol triallyl ether, 2,2'-azobis (2,4-di A vinyl polymer particle of Example 3 having a sodium salt-type carboxyl group was obtained in the same manner as in Example 1 except that a monomer mixture consisting of 1 part of methylvaleronitryl) was used. Table 1 shows the results of evaluating the properties of these particles.

[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 triallyl ether, 2,2'-azobis (2,4-di A vinyl polymer particle of Example 4 having a sodium salt-type carboxyl group was obtained in the same manner as in Example 1 except that a monomer mixture consisting of 1 part of methylvaleronitryl) was used. Table 1 shows the results of evaluating the properties of these particles.

[Table 1]

As can be seen from Table 1, in Comparative Example 1 in which an ether-based crosslinking agent was not used and Comparative Example 2 in which an ester-based crosslinking agent was not used, dehydration was poor and the degree of water swelling was large. In particular, in Comparative Example 1, significantly longer time was required than other examples in dehydration and disintegration after hydrolysis. In Example 2, carbon black was added as a pigment, and the obtained particles exhibited good black color and had moisture absorption performance equivalent to that of Example 1 in which no pigment was added.

[Example 5]

67 parts of vinyl polymer particles of Example 2, 500 parts of urethane resin "Crisbon NY-373" (manufactured by DIC Corporation) (20% solid content), 175 parts of dimethylformamide were mixed, and coated on release paper do. Then, the release paper after coating was immersed in water, solvent-removed, and dried to obtain a urethane resin sheet containing the vinyl polymer particles of the present invention. The mass per area of this sheet was 145 g/m ² .

In addition, according to the method described in the measurement of the moisture absorption amount of the sheet bar, temperature 20 ℃, 40% relative humidity under a 14.9g / m ^2, temperature 40 ℃, relative humidity of 90% under was 47.8g / m ^2. On the other hand, the result of the same moisture absorption measurement for a sheet produced using only the urethane resin "Crisbon NY-373" was 0.28 g/m ² at a temperature of 20°C and a relative humidity of 40%, and a temperature of 40°C, relative It was 0.32 g/m ² under 90% humidity. From the above, it is understood that by containing the vinyl polymer particles of the present invention, a sheet having high hygroscopicity is obtained. In addition, since this sheet has a large difference in the amount of moisture absorption in a low-humidity atmosphere and a high-humidity atmosphere, it can also be used for humidity control in which moisture absorbed in a high-humidity atmosphere is moisture-proofed in a low-humidity atmosphere.

Claims (9)

Spherical vinyl polymer particles having a carboxyl group of 1 to 10 mmol/g and containing an ester crosslinking agent and an ether crosslinking agent not having an ester structure as a copolymerization component, wherein the copolymerization ratio of the ester crosslinking agent is 5 to 30 wt. %, and the copolymerization ratio of the ether-based crosslinking agent not having an ester structure is 0.01 to 10% by weight. The vinyl polymer particle according to claim 1, wherein a microparticle-like additive is contained inside the particle. The vinyl polymer particle according to claim 1, wherein the value of the degree of water swelling represented by the following formula is 1 to 3.
Formula: [water swelling degree]=X/Y
From here,
X: The height from the bottom of the test tube to the top of the settled particles after 1 g of particles are put in a test tube with a diameter of 16.5 mm, and then water is added to a scale of 10 ml, and the test tube is made vertical and allowed to stand.
Y: The height from the bottom of the test tube to the top of the settled particles after 1 g of particles are placed in a test tube with a diameter of 16.5 mm, and then methyl ethyl ketone is added to a scale of 10 ml, and the test tube is made vertical and allowed to stand. A resin molded article containing the vinyl-based polymer particles according to any one of claims 1 to 3. A coating composition containing the vinyl polymer particles according to any one of claims 1 to 3. An ink composition containing the vinyl polymer particles according to any one of claims 1 to 3. A fiber structure containing the vinyl-based polymer particles according to any one of claims 1 to 3. delete delete

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