TW201527331A - Vinylic polymer particle and composition containing the same - Google Patents

Abstract

Some problems such as having particular color, low degree of polymerization, need of removing residual monomers, need of using an organic solvents in manufacturing process, being micronizered and others due to dryness as well as contraction caused by moisture-absorbing and desorbing property, etc., and usage, manufactured process, durability are existed in a moisture-absorbing and desorbing particle which is used usually. The disclosure is an invention accomplished in view of the present situation of prior arts, and is objective to provide a moisture-absorbing and desorbing and desorbing particle that can be made to have any color, and is easily manufactured, but is not being micronizered even dryness and others, as well as to provide a resin molded article and various compositions comprising the particle. A vinyl-based polymer particle in a spherical form includes a carboxyl group, and comprises a copolymer component formed by copolymerizing an ester-based crosslinking agent with an ether-based crosslinking agent which has none of ester structure.

Description

Vinyl polymer particles and compositions containing the same

The present invention relates to a vinyl polymer particle and a resin molded body or various compositions containing the same.

In the past, several examples have been proposed which can be used as hygroscopic resin particles. For example, Patent Document 1 discloses a high moisture absorption and moisture absorbing fine particle characterized in that it is a crosslinked acrylonitrile-based polymer microparticle which can increase a nitrogen content by 1.0 to 15.0% by weight via hydrazine crosslinking and is introduced. It is formed by having a base type carboxyl group of 1.0 mmol/g or more. However, since the particles have a deep pink color caused by the hydrazine crosslinked structure, their use is limited.

Further, Patent Document 2 discloses a moisture absorbing and dehydrating polymer which has a calcium salt type carboxyl group of 1.0 to 8.0 meq/g and has a crosslinked structure obtained by copolymerizing divinylbenzene. A vinyl polymer. However, there are problems such as strong odor of divinylbenzene, low polymerization rate, and troublesome removal of residual monomers.

Further, Patent Document 3 discloses a moisture-retaining particle which can be obtained by hydrolyzing a carboxylic acid ester present on the surface of the crosslinked polyacrylate particles. However, it is necessary to carry out a hydrolysis step in a mixed solvent of an aqueous alkaline solution and an organic solvent to obtain the particles, and it is necessary to dry the water by replacing the water with an organic solvent such as methanol or diethyl ether to make it dry. Therefore, there are problems in the production process that must use organic solvents, process complexity, and environmental load. In addition, there are many cracks on the surface of the particles, and the surface layer portion is disintegrated during drying to be micronized. "Previous Technical Literature" "Patent Literature"

[Patent Document 1] JP-A-2009-074979 (Patent Document 3) JP-A-2011-126979

"The subject to be solved by the invention"

As described above, the conventional moisture absorbing and drying particles have problems such as use, production process, durability, and the like. The present invention has been made in view of the state of the art of the prior art, and an object of the invention is to provide a moisture absorbing and dehydrating particle which can be produced in any color, is easy to produce, and is not micronized by drying or the like, and A resin molded body containing the particles and various compositions are provided. "Means to solve problems"

That is, the above object of the present invention can be achieved by the following means. (1) A spherical ethylene-based polymer particle which has a carboxyl group and which comprises a copolymerization component of an ester-based crosslinking agent and an ether-based crosslinking agent having no ester structure. (2) The ethylene-based polymer particle according to (1), which has a carboxyl group of 1 to 10 mmol/g. (3) The ethylene-based polymer particles according to (1) or (2), wherein the ester-based crosslinking agent has a copolymerization ratio of 5 to 30% by weight, and the ether-based crosslinking has no ester structure. The copolymerization ratio of the agent is 0.01 to 10% by weight.

(4) The ethylene-based polymer particles according to any one of (1) to (3), wherein the particles contain a fine particulate additive. (5) The ethylene-based polymer particles according to any one of (1) to (4), wherein the water swelling degree represented by the following formula is 1 to 3, and the formula: [water swelling degree] = X ⁄ Y In this formula, X: 1 g of the particle is placed in a test tube with a diameter of 16.5 mm, then water is added up to a 10 ml mark, and the test tube is allowed to stand still after the test. The height from the bottom of the tube to the top of the settled particles; Y: 1 g of the particles were placed in a test tube with a diameter of 16.5 mm, followed by the addition of methyl ethyl ketone to a 10 ml mark, and the test tube was placed The height from the bottom of the test tube to the top of the settled particles after standing still.

(6) A resin molded article comprising the ethylene-based polymer particles according to any one of (1) to (5). (7) A coating composition comprising the ethylene-based polymer particles according to any one of (1) to (5). (8) An ink composition comprising the ethylene-based polymer particles according to any one of (1) to (5). (9) A fiber structure comprising the ethylene-based polymer particles according to any one of (1) to (5). "The Effect of the Invention"

Since the ethylene-based polymer particles of the present invention not only have excellent moisture absorption and desorption performance but also easily contain various additives in the particles, they can be made wet by any color, for example, by containing a pigment. Sex particles. In the vinyl polymer particles of the present invention, for example, a resin molded body such as a synthetic leather or a film which is important in appearance, a composition such as a paint or ink, a fiber structure such as a non-woven fabric, paper, or cloth, or the like can be used. Among them, the moisture absorption and secretion imparting agent.

The ethylene-based polymer particles of the present invention are those having a carboxyl group. The carboxyl group is a polar group having high hydrophilicity; by containing the group, the ethylene-based polymer particles of the present invention can exhibit moisture absorption and desorption performance. In particular, in the case where the counter ion of the carboxyl group is an ion other than the hydrogen ion, in particular, excellent moisture absorption and desorption performance can be exhibited.

The type of the salt of the basic type carboxyl group, that is, the counter cation, for example, may be an alkali metal such as Li, Na, K, Rb or Cs; or an alkaline earth metal such as Be, Mg, Ca, Sr or Ba; Other metals such as Cu, Zn, Al, Mn, Ag, Fe, Co, Ni, etc.; NH ₄ , amine, and the like. Among them, Na, K, Mg, Ca, Zn, Al, Ag, NH ₄ and the like are preferable from the viewpoint of high moisture absorption and desorption performance, ease of use, and safety.

On the other hand, in the case where the counter cation of the carboxyl group is a hydrogen ion (hereinafter referred to as a water-type carboxyl group), although it is not a basic type carboxyl group, the moisture absorption and desorption performance can be exhibited; and, in addition, a base such as ammonia or an organic amine compound The base material is also excellent in properties such as adsorption, antivirality, or antiallergic properties.

Further, in the present invention, even if various kinds of the above-mentioned carboxyl groups are mixed, it is possible to appropriately combine them in accordance with the required properties.

The amount of the carboxyl group in the ethylene-based polymer particles of the present invention is preferably from 1 to 10 mmol/g, more preferably from 3 to 9 mmol/g, still more preferably from 5 to 8 mmol/g. When the amount of the carboxyl group is more than 10 mmol/g, the ratio of the cross-linking structure to be described later becomes too small, and it becomes a substance similar to the highly water-absorptive resin, and thus the adhesiveness due to moisture absorption and swelling due to water may occur. Problems such as excessive volume changes. On the other hand, when the amount of carboxyl groups becomes smaller and smaller, the moisture absorption and desorption is more and more reduced. Especially in the case where the amount of carboxyl groups is less than 10 mmol/g, there are many cases where sufficient moisture absorption and desorption performance cannot be obtained. of.

The method of introducing a carboxyl group into the ethylene-based polymer particles may, for example, be a monomer having a structure capable of being chemically modified by hydrolysis or the like to be converted into a carboxyl group, and used in a copolymerization component to obtain a polymerization. A method in which a particle is introduced into a carboxyl group by chemical modification and then converted into a carboxyl group having a desired counter ion.

A single system having a structure in which a carboxyl group can be obtained by a hydrolysis treatment, a monomer having a cyano group such as acrylonitrile or methacrylonitrile; acrylic acid, methacrylic acid, maleic acid, itaconic acid, vinyl propionic acid, or the like. Anhydrides and their derivatives. Examples thereof include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and n-butyl (meth)acrylate. An ester compound such as an ester, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate or hydroxyethyl (meth)acrylate; (meth)acrylamide, dimethyl ( Methyl) decylamine such as acrylamide, monoethyl (meth) acrylamide or n-t-butyl (meth) acrylamide.

Further, a method of forming a carboxyl group into a desired base form, for example, may be a solution of the obtained polymer particles and a desired counter ion containing a large amount of an ionic alkali metal alkaline earth metal described later or a method in which an acid reacts to perform ion exchange or the like; the ion refers to an alkali metal ion such as Li, Na, K, Rb, or Cs; an alkaline earth metal ion such as Be, Mg, Ca, Sr, or Ba; Cu, Zn, Other metal ions such as Al, Mn, Ag, Fe, Co, and Ni; organic cations such as NH ₄ and amine.

In addition, the ethylene-based polymer particles of the present invention are particles obtained by copolymerizing an ester-based crosslinking agent and an ether-based crosslinking agent to introduce a crosslinked structure. As described above, since the ethylene-based polymer particles of the present invention contain a large amount of carboxyl groups having high affinity with water, they are adhesive to water, extremely swollen in water, and depending on the case. It is possible to dissolve in water; in the case where particles such as these are blended with a resin or the like, there is a case where the characteristics are adversely affected. The crosslinked structure is a structure used for the purpose of not causing such defects.

The ester crosslinking agent used in the present invention is a crosslinking agent having an ester structure and two or more double bonds, and preferably having three or more double bonds. The ester-based crosslinking agent may be, for example, a di(meth)acrylate, a tri(meth)acrylate, a tetra(meth)acrylate, or a hexa(meth)acrylate. Classes, etc. Here, the (meth)acrylate means both a methacrylate and an acrylate.

Specifically, examples thereof may be, for example, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, and 2-hydroxy-3-propenyloxypropyl (meth)acrylate. Alcohol ester, propoxylated ethoxylated bisphenol A di(meth) acrylate, ethoxylated bisphenol A di(meth) acrylate, propoxylated bisphenol A di(meth) acrylate Ester, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, di(a) Propylene glycol propylene glycol, propylene glycol poly(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylic acid Ester, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like.

Further, the ether crosslinking agent used in the present invention is a crosslinking agent having an ether bond and two or more double bonds and not containing an ester structure; more preferably, it contains three or more double bonds. The ether crosslinking agent may, for example, be an aryl ether, an aryl vinyl ether or a vinyl ether. Among these, it is more preferable to contain three or more double bonds. Specifically, examples thereof may be a diaryl ether, a trimethylolpropane diaryl ether, a pentaerythritol triaryl ether, an allyl vinyl ether, a 1,4-butanediol divinyl ether, Cyclohexane dimethanol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, and the like.

In the present invention, it is necessary to use both of the above-described ester crosslinking agent and ether crosslinking agent. In the case where only the ester-based crosslinking agent is used, the particles are colloidalized in the hydrolysis described later, and it takes a long time to dehydrate and dry thereafter. Further, after drying, the particles are agglomerated with each other, so that it takes a long time to break down and the like, and the particle shape also becomes easily damaged. Such a situation is considered to be caused by hydrolysis, so that most of the ester structure of the ester-based crosslinking agent is decomposed, so that the number of cross-linking structures is reduced.

In addition, in the case of using only the ether-based crosslinking agent, it is not necessary to spend as much time as in the case of using only the above-described ester-based crosslinking agent in dehydration and drying after hydrolysis described later. However, since it is extremely swelled when the water is absorbed again, in the case of a resin molded body or the like to which the particles are added, when it is wetted by water or the like, a shape deformation or a colloidal colloid falling off occurs. Bad situation.

On the other hand, in the case of using both of the above-described ester-based crosslinking agent and ether-based crosslinking agent, it is possible to easily perform gelation dehydration without hydrolysis, and it is possible to obtain spherical particles. Further, since the obtained particles can suppress swelling even if they are wetted by water, the above-mentioned problems are hard to occur.

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

Further, the ethylene-based polymer particles of the present invention are ones having spherical particles. Specifically, the circularity measured by the method described later is 0.9 or more, preferably 0.95 or more. Since it is spherical, the particles are not broken or damaged by stirring or the like when mixed with a resin or the like, and micronization can be suppressed. Therefore, it is possible to impart a stable function to the resin molded body or the like.

Further, the water swelling degree of the ethylene-based polymer particles of the present invention is preferably from 1 to 3, more preferably from 1.5 to 3, as measured by a method described later. When the water swelling degree is more than 3, the volume change during drying and moisture absorption of the particles becomes excessively large, and when it is used as an additive such as a resin molded body, deformation of the resin molded body is promoted. Or it may be deteriorated, or the particles may easily fall off from the resin molded body. On the other hand, when the water swelling degree is less than 1, the moisture absorption amount is excessively restricted, and sufficient moisture absorption and desorption performance cannot be obtained. Such water swelling degree can be controlled by adjusting the amount of carboxyl groups in the ethylene-based polymer particles, the kind of the counter ion, and the copolymerization ratio of the crosslinking agent.

Further, the ethylene-based polymer particles of the present invention can be produced by suspension polymerization described later. Although the monomer droplets are dispersed in a medium for polymerization in suspension polymerization, the present invention can be added to the monomer droplets by polymerization and polymerization, so that the above-mentioned moisture absorption and desorption performance can be added. In addition to the functions, it is also possible to attach other various functions. Such an additive may be, for example, a preservative, an antifungal agent, an antibacterial agent, an antioxidant, an ultraviolet absorber, a pigment, a fragrance, a deodorant, an adsorbent, an inorganic moisture absorbent, and a photocatalyst particle. Various items, etc., however, it is preferred to maintain the function even after the hydrolysis treatment. Furthermore, it is of course also possible to use a plurality of additives.

In the case where a pigment is added to the ethylene-based polymer particles of the present invention, moisture-absorbent particles having a desired color can be obtained. For example, a composition such as a synthetic leather such as a synthetic leather or a film, a composition such as a paint or ink, a non-woven fabric, a paper, a fabric, or the like, which does not give an impression to the appearance, can be provided. It is extremely useful for sucking moisture and so on.

The pigment which can be used is, for example, a natural pigment, a fluorescent pigment, an inorganic pigment or an azo pigment, an organic pigment such as a polycyclic pigment, or the like. Among them, the inorganic pigment, for example, may be zinc white, lead white, zinc antimony white, titanium dioxide, precipitated barium sulfate, barite powder, lead dan, iron oxide red, yellow lead, zinc yellow. , ultramarine blue, Prussian blue, carbon black, titanium black and so on. Further, examples of the azo-based pigment include insoluble azo pigments and the like. An azo lake pigment, a polycondensation azo pigment, a chelate azo pigment, or the like; a polycyclic pigment, for example, which may be a phthalocyanine pigment, an anthraquinone and an anthrone pigment, a thioindigo pigment, A quinacridone pigment, a dioxazine pigment, an isoindolinone pigment, a quinophthalone pigment, or the like. In addition to the above, for example, the pigment may also be, for example, a dyed lake pigment, a pyridazine pigment, a nitroso pigment, a nitro pigment, or the like.

The amount of the additive to be added is not particularly limited, and may be set in such a manner as to achieve a desired function; however, for example, from the viewpoint of being able to sufficiently develop color and stably carry out polymerization in the case of a pigment, The weight of the polymer constituting the ethylene-based polymer particles is desirably preferably from 0.1 to 5% by weight, more preferably from 0.4 to 3% by weight.

Further, the average particle diameter of the ethylene-based polymer particles of the present invention is preferably from 1 to 500 μm, more preferably from 5 to 150 μm. When the average particle diameter is more than 500 μm, there is a case where a defect described later occurs when it is added to a resin to be molded, and for example, a molding failure or the like is likely to occur, and even if the surface can be molded, the unevenness is caused to cause an appearance. Poor, causing particles to fall off during use. On the other hand, when the average particle diameter is less than 1 μm, it is difficult to carry out suspension polymerization.

In addition, in the case where the ethylene-based polymer particles of the present invention are used for the purpose of imparting moisture absorption and desorption performance to a resin molded body or the like, the saturated moisture absorption rate of the particles at 20 ° C × 65% RH is ideal. The upper portion is preferably 15% or more, more preferably 20% or more, and still more preferably 30% or more. The adjustment of the saturated moisture absorption rate can be mainly adjusted by changing the amount of the alkali type carboxyl group in the particles or the like.

The method for producing the ethylene-based polymer particles of the present invention may, for example, be a method of hydrolyzing particles obtained by suspension polymerization. Specifically, first, a monomer having a structure which can be chemically modified to be converted into a carboxyl group, an ester crosslinking agent, an ether crosslinking agent having no ester structure, a polymerization initiator, and optionally A monomer mixture in which the above-described additive and other vinyl monomer are mixed is prepared into droplets, dispersed in an aqueous solvent, and heated and polymerized 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 or an acid containing a large amount of a desired counter ion acts to perform ion exchange. This can be made. Here, the basic compound used in the hydrolysis may, for example, be an alkali metal hydroxide, ammonia or the like; and an inorganic acid, for example, may be nitric acid, sulfuric acid, hydrochloric acid or the like; The organic acid, for example, may be formic acid, acetic acid or the like.

By including the ethylene-based polymer particles of the present invention obtained as described above in various materials and compositions such as a resin molded body, a coating composition, an ink composition, and a fiber structure, The materials and compositions provide functions such as moisture absorption and desorption, deodorization, adsorption of alkaline substances, antiviral properties, or antiallergic properties. In particular, since the ethylene-based polymer particles of the present invention can be colored in an arbitrary color by a pigment, they can be suitably used for materials and compositions that emphasize color.

The resin molded body of the present invention may be, for example, a fiber, a synthetic leather, an artificial leather, a film, a sheet, or the like. For example, in the case of a fiber, the vinyl polymer particles of the present invention may be mixed in a spinning dope obtained by dissolving dimethyl acetamide of an urethane resin, or may be dissolved. A spinning dope or the like obtained by using an aqueous solution of an acrylonitrile-based polymer of sodium thiocyanate, and processing it into a fiber form by a spinning method to produce a urethane or a acrylate having a moisture absorption and desorption property. Ester fiber.

Further, in the case of artificial leather, the ethylene-based polymer particles of the present invention may be mixed in a liquid obtained by dissolving dimethyl acetamide of a urethane resin, and then coated thereon. On a non-woven fabric composed of polyester fibers, artificial leather having moisture absorption and desorption properties is produced by removing the solvent in an aqueous solution and drying it.

The fibrous structure of the present invention may be, for example, a silk, a braid, a woven fabric, a non-woven fabric, paper, or the like. These articles can be produced by using the fibers of the ethylene-based polymer particles of the present invention obtained as described above, and in addition, the ethylene-based polymer particles of the present invention can be fixedly attached to a general yarn. Fabricated, woven, non-woven, paper, etc. are produced.

The amount of the ethylene-based polymer particles of the present invention added to the material or composition as described above, which can exhibit the desired moisture absorption and desorption property, deodorant property, adsorption property of the basic substance, and antiviral property. In the case of the resin molded body, the amount of addition of the resin molded body is preferably 5 to 60% by weight, based on the weight of the resin molded body. When the amount is less than 5% by weight, the properties of the ethylene-based polymer particles of the present invention are not suitable for use. When the amount is more than 60% by weight, physical properties such as strength of the molded article may be lowered or friction may be used. A problem that causes problems such as falling off of the vinyl polymer particles. [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 addition, the "part" and "percentage" in the examples are based on the weight basis unless otherwise specified. First, an evaluation method of various characteristics will be described.

(1) Circularity The circularity referred to in the present invention means the circularity of the particles calculated by the following formula. The circularity of the particle projection image = (the circumference of the circle of the same area as the projected area of the particle) ∕ (the circumference of the particle projection image) The average circularity of the particle projection image = the circularity of the particle, that is, positive In the case of a circle, the circularity is 1; and its value becomes smaller as the degree of the indefinite shape increases. The value of such a circularity can be measured by, for example, a flow type particle image analyzer "FPIA-3000S" manufactured by Sysmex Co., Ltd.

(2) Dehydration property An aqueous dispersion containing 5% of the sample particles was prepared, and the state at the time of suction filtration of the aqueous dispersion was evaluated in accordance with the following criteria. ○: Filtration is completed within 1 hour after the start of suction. ×: After the start of suction, filtration is not completed even after 1 hour has elapsed.

(3) Amount of carboxyl group The sample was dispersed in water, and 1 N hydrochloric acid was added thereto to adjust to pH 2.0. Next, the sample was separated by filtration, dried, and the weight (W1 [g]) was measured. The sample after the measurement of the weight was again dispersed in water, and titrated with a 0.1 N aqueous sodium hydroxide solution. From the obtained titration curve, the consumption amount of the aqueous sodium hydroxide solution consumed by the carboxyl group was determined, and the amount of carboxyl groups was calculated by the following formula. The amount of carboxyl groups [mmol/g] = 0.1 × V / W1

(4) Water swelling degree 1 g of the dried sample particles were placed in a test tube having a diameter of 16.5 mm. Next, water was added to a scale of 10 ml to swell the particles. After the test tube was stood upright and allowed to stand for 60 hours, the height (X [cm]) from the bottom of the test tube to the topmost portion of the settled particles was measured. On the other hand, except that methyl ethyl ketone was used instead of water, the same method was used to measure the swelling of the sample particles with methyl ethyl ketone from the bottom of the test tube to the top of the settled particles. Height (Y[cm]). From the obtained measured values, the water swelling degree was calculated by the following formula. Water swelling degree = X / Y

(5) The average particle diameter is measured by using a laser diffraction particle size distribution measuring device "SALD-200V" manufactured by Shimadzu Corporation, using water as a dispersing agent, and obtaining an average particle from a particle size distribution based on a volume basis. Path (μm).

(6) Saturated moisture absorption rate of the particles A sample of about 5.0 g was taken, dried at 105 ° C for 16 hours, and the weight (W2 [g]) was measured. Next, the sample was placed in a thermo-hygrostat adjusted to a temperature of 20 ° C and a relative humidity of 65% for 24 hours. The weight of the sample (W3 [g]) which had been hygroscopic so placed was measured. From the above measurement results, the saturated moisture absorption rate was calculated by the following formula. Saturated moisture absorption rate [%]=(W3-W2) /W2×100

(7) Moisture absorption amount of the sheet A square sample having a side length of 10 cm was taken, dried at 105 ° C for 16 hours, and the weight (W3 [g]) was measured. Next, the sample was placed in a thermo-hygrostat adjusted to a temperature of 20 ° C and a relative humidity of 40%, and left for 16 hours. The weight of the sample which had been hygroscopic so placed (W5 [g]) was measured. Next, the sample after measurement was placed in a thermo-hygrostat adjusted to a temperature of 40 ° C and a relative humidity of 90%, and after standing for 2 hours, the weight (W6 [g]) of the sample was measured. From the above measurement results, the moisture absorption rate of the sheet under each condition was calculated by the following formula. Moisture absorption rate at a temperature of 20 ° C and a relative humidity of 40% [g/m ² ]=(W5-W4)/0.01 Moisture absorption rate at a temperature of 40 ° C and a relative humidity of 90% [g/m ² ] = (W6- W4)/0.01

[Example 1] 82 parts of methyl acrylate, 17 parts of trimethylolpropane trimethacrylate, 1 part of pentaerythritol triaryl ether, 1 part of 2, 2'-azobis (2, 4) A monomer mixture composed of - dimethyl valeronitrile was dispersed in 400 parts of water. Then, the polymerization was carried out at 50 ° C for 2 hours, and the raw material particles were obtained by washing with water and dehydration. By mixing 150 parts of the raw material particles with 810 parts of water, 40 parts of sodium hydroxide was added, and then hydrolysis was carried out at 95 ° C for 10 hours, and washed with water, dehydrated, dried, and cleaved to obtain sodium. The ethylene-based polymer particles of Example 1 having a base-type carboxyl group. The characteristics of the particles were evaluated, and the evaluation results are shown in Table 1. Further, an SEM photograph of the particles is shown in Fig. 1 .

[Comparative Example 1] Except using 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 that the monomer mixture was replaced with the monomer mixture of Example 1, particles of Comparative Example 1 having a sodium base type carboxyl group were obtained. The characteristics of the particles were evaluated, and the evaluation results are shown in Table 1.

[Comparative Example 2] A monomer composed of 80 parts of methyl acrylate, 20 parts of pentaerythritol triaryl ether, and 1 part of 2,2'-azobis(2,4-dimethylvaleronitrile) was used. In the same manner as in Example 1, except that the mixture was replaced with the monomer mixture in Example 1, particles of Comparative Example 2 having a sodium base type carboxyl group were obtained. The characteristics of the particles were evaluated, and the evaluation results are shown in Table 1.

[Example 2] Except that 80 parts of methyl acrylate, 19 parts of trimethylolpropane trimethacrylate, 1 part of pentaerythritol triaryl ether, and 1 part of 2,2'-azobis (2 parts) were used. Instead of the monomer mixture in Example 1, except that the monomer mixture of 4-dimethylvaleronitrile and 2 parts of carbon black was used, the particles were prepared in the same manner as in Example 1 to obtain a sodium base. The particles of Example 2 having a base carboxyl group. The characteristics of the particles were evaluated, and the evaluation results are shown in Table 1.

[Example 3] Except that 85 parts of methyl acrylate, 10 parts of trimethylolpropane trimethacrylate, 5 parts of pentaerythritol triaryl ether, and 1 part of 2,2'-azobis (2 parts) were used. Instead of the monomer mixture in Example 1, a monomer mixture composed of 4-dimethylvaleronitrile was used to prepare particles in the same manner as in Example 1 to obtain Example 3 having a sodium base type carboxyl group. Ethylene polymer particles. The characteristics of the particles were evaluated, and the evaluation results are shown in Table 1.

[Example 4] Except that 69.5 parts of methyl acrylate, 30 parts of trimethylolpropane trimethacrylate, 0.5 part of pentaerythritol triaryl ether, and 1 part of 2,2'-azobis (2 parts) were used. Instead of the monomer mixture in Example 1, a monomer mixture composed of 4-dimethylvaleronitrile was used to prepare particles in the same manner as in Example 1 to obtain Example 4 having a sodium base type carboxyl group. Ethylene polymer particles. The characteristics of the particles were evaluated, and the evaluation results are shown in Table 1.

As is clear 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, particles having poor dehydration properties and large water swelling degree were obtained. In particular, in Comparative Example 1, the time required for dehydration and cracking after hydrolysis was more than that of the other examples. In Example 2, although carbon black was added as a pigment, the obtained particles showed a good black color and had the same moisture absorption performance as in Example 1 in which no pigment was added.

[Example 5] 67 parts of the ethylene-based polymer particles of Example 2 and 500 parts of a urethane resin "crisvon NY-373" (manufactured by Dainippon Ink Chemical Industry Co., Ltd.) (solid content) 20%), 175 parts of dimethylacetamide were mixed and coated on a release paper. Next, the coated release paper is immersed in water to remove the solvent, and dried to obtain a urethane resin sheet containing the ethylene-based polymer particles of the present invention. The sheet had a basis weight of 145 g/m ² .

Further, when the moisture absorption amount of the sheet was measured according to the method described above, the obtained value was 14.9 g/m ² at a temperature of 20 ° C and a relative humidity of 40% or less; and at a temperature of 40 ° C and a relative humidity. Below 90% is 47.8 g/m ² . On the other hand, as a result of measuring the moisture absorption of the sheet produced using only the urethane resin "crisvon NY-373", the value was 0.28 g/m at a temperature of 20 ° C and a relative humidity of 40% or less. ² ; at a temperature of 40 ° C, a relative humidity of 90% or less is 0.32 g / m ² . From the above results, it was found that a sheet having high hygroscopicity can be obtained by containing the ethylene-based polymer particles of the present invention. In addition, since the sheet has a large difference in moisture absorption under low-humidity ambient gas and high-humidity ambient gas, the sheet can also be used to: absorb moisture in a high-humidity environment gas in a low-humidity environment. It is used for the so-called humidity adjustment such as dehumidification under gas.

Fig. 1 is a SEM photograph of an example of a vinyl polymer.

Claims (9)

A spherical ethylene-based polymer particle having a carboxyl group and comprising a copolymerization component of an ester crosslinking agent and an ether crosslinking agent having no ester structure. The ethylene-based polymer particles according to claim 1 which have a carboxyl group of 1 to 10 mmol/g. The ethylene-based polymer particle according to claim 1 or 2, wherein a copolymerization ratio of the ester-based crosslinking agent is 5 to 30% by weight, and a copolymerization ratio of the ether-based crosslinking agent having no ester structure is 0.01 ~ 10% by weight. The ethylene-based polymer particles according to any one of claims 1 to 3, which contain a fine particulate additive in the inside of the particles. The ethylene-based polymer particles according to any one of claims 1 to 4, wherein the water swelling degree represented by the following formula is 1 to 3, and the formula: [water swelling degree] = X ⁄ Y Medium, X: 1 g of the particles were placed in a test tube having a diameter of 16.5 mm, followed by the addition of water to a 10 ml mark, and the test tube was allowed to stand still from the bottom of the test tube to the settled particles. Height at the top; Y: Place 1 g of the particles in a test tube with a diameter of 16.5 mm, then add methyl ethyl ketone to a 10 ml mark, and place the test tube upright after standing The height from the bottom of the test tube to the top of the settled particles. A resin molded body containing the ethylene-based polymer particles according to any one of claims 1 to 5. A coating composition containing the ethylene-based polymer particles according to any one of claims 1 to 5. An ink composition comprising the ethylene-based polymer particles according to any one of claims 1 to 5. A fiber structure comprising the ethylene-based polymer particles according to any one of claims 1 to 5.