JP2022096002A - Gelatinizer for alkaline batteries and alkaline battery - Google Patents

Abstract

To provide a gelatinizer for alkaline batteries which excels in the ability of preventing precipitation of zinc powder, etc., in an alkaline electrolyte, and with which performance can be expressed by one material without using a plurality of materials.SOLUTION: Provided is a gelatinizer for alkaline batteries which contains a cross-linked polymer (A) that includes water soluble vinyl monomer (a1) and/or vinyl monomer (a2) that becomes (a1) by hydrolysis and a cross-linking agent (b) as essential constituent monomers, and satisfies conditions (1) to (3). (1) The component of the cross-linked polymer (A) that dissolves in saline is 5-20 wt.% based on the weight of (A). (2) The ratio (Mw/Mn) of weight average modular weight (Mw) to number average molecular weight (Mn) of a component of the cross-linked polymer (A) that dissolves in saline, the molecular weight of which is 100,000 or less, is 4.0 to 6.0. (3) The viscosity of a mixed liquid at 25°C in which a gelatinizer (G) is added 2 wt.% to 40 wt.% potassium hydroxide aqueous solution, is 10 to 60 Pa-s.SELECTED DRAWING: None

Description

The present invention relates to a gelling agent for an alkaline battery and an alkaline battery. More specifically, the present invention relates to a gelling agent for the negative electrode of an alkaline battery mainly composed of an alkaline electrolytic solution and zinc powder, and an alkaline battery using the same.

Conventionally, the negative electrode material of an alkaline battery has been a mixture of a high-concentration alkaline electrolytic solution (containing a high-concentration potassium hydroxide aqueous solution and, if necessary, zinc oxide, etc.) and zinc powder and / or zinc alloy powder. It is mainly used. Zinc powder and the like in the alkaline electrolytic solution tend to settle, and for the purpose of preventing this, the alkali metal salt powder of high polymerization degree crosslinked polyacrylic acid is used alone as a gelling agent, or the alkali metal salt of carboxymethyl cellulose is used. Have been proposed in combination with (for example, Patent Document 1). Further, there has been proposed a cross-linked branched poly (meth) acrylic acid having a different particle size and a salt thereof mixed and used as a gelling agent (see, for example, Patent Document 2).

Japanese Patent No. 2775829 Japanese Patent No. 3371532

However, the gelling agents described in Patent Documents 1 and 2 do not have sufficient anti-sedimentation properties for zinc powder and the like in the alkaline electrolytic solution, and in terms of maintaining the discharge characteristics of the battery for a long period of time and impact resistance. It wasn't always satisfactory. In addition, it is necessary to mix a plurality of materials, which causes a problem that the number of production processes increases.
The present invention has been made in view of these problems, and an object of the present invention is to have excellent sedimentation prevention properties such as zinc powder in an alkaline electrolytic solution, and to use one material without using a plurality of materials. It is an object of the present invention to provide a gelling agent for an alkaline battery capable of exhibiting performance.

The present inventors have arrived at the present invention as a result of diligent studies to solve the above problems. That is, the present invention contains a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes (a1) by hydrolysis and a crosslinked polymer (A) containing a crosslinking agent (b) as an essential constituent monomer. The gelling agent (G) for an alkaline battery satisfying the following (1) to (3); the alkaline battery containing the gelling agent (G) and zinc powder.
(1) The amount of the soluble component of the crosslinked polymer (A) in physiological saline is 5 to 20% by weight based on the weight of (A).
(2) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the components having a molecular weight of 100,000 or less among the soluble components of the crosslinked polymer (A) in physiological saline is It is 4.0 to 6.0.
(3) The viscosity of a mixed solution prepared by adding 2% by weight of the gelling agent (G) to a 40% by weight potassium hydroxide aqueous solution at 25 ° C. is 10 to 60 Pa · s.

The gelling agent (G) of the present invention and an alkaline battery using the same have the following effects.
(1) Since the gelling agent (G) of the present invention is excellent in preventing the sedimentation of zinc powder and the like in the negative electrode material, when used in an alkaline battery, the discharge duration and the discharge duration are small and for a long period of time. It is possible to manufacture a battery having extremely excellent impact resistance.
(2) Since the gelling agent (G) of the present invention can exhibit performance with one material without using a plurality of materials, the production process of the battery can be reduced as much as possible, and the production cost is excellent. ..
(3) Since the negative electrode material to which the gelling agent (G) of the present invention is added has an appropriate viscosity at the time of filling and the negative electrode material drains well, the filling amount of the negative electrode material varies per battery. Because there are few batteries, it is possible to produce batteries with uniform quality even during mass production, and even with small size batteries, the negative electrode material can be filled uniformly and at high speed, so batteries with uniform quality can be produced. can.

The gelling agent (G) for an alkaline battery of the present invention contains a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes (a1) by hydrolysis and a cross-linking agent (b) as essential constituent monomers. Contains the crosslinked polymer (A).

In the present invention, the water-soluble vinyl monomer means a vinyl monomer having a property of dissolving at least 100 g in 100 g of water at 25 ° C.
The vinyl monomer (a2) which becomes the water-soluble vinyl monomer (a1) and / or the vinyl monomer (a1) by hydrolysis is not particularly limited, and is, for example, the water-soluble radical polymerization monomer described in JP-A-2005-075982. Can be mentioned. Of these, from the viewpoint of discharge characteristics, the water-soluble vinyl monomer (a1) is preferable, more preferably an anionic vinyl monomer, and particularly preferably a vinyl group-containing carboxylic acid (salt) having 3 to 30 carbon atoms {unsaturated monocarboxylic acid). Acids (salts) [(meth) acrylic acid, crotonic acid, cinnamic acid and their salts, etc.]; unsaturated dicarboxylic acids (salts) (maleic acid, fumaric acid, citraconic acid, itaconic acid and their salts, etc.); and Monoalkyl (1 to 8 carbon atoms) ester of unsaturated dicarboxylic acid (maleic acid monobutyl ester, fumaric acid monobutyl ester, maleic acid ethylcarbitol monoester, fumaric acid ethylcarbitol monoester, citraconic acid mono Butyl esters, itaconic acid glycol monoesters, etc.}, particularly preferably unsaturated monocarboxylic acids (salts), most preferably acrylic acids (salts).

In the present invention, (meth) acrylic acid means acrylic acid and / or methacrylic acid, and "... acid (salt)" means "... acid" and / or "... acid acid". means. Examples of the salt include alkali metal salts such as potassium, sodium and lithium, and alkaline earth metal salts such as calcium.

The unit derived from the water-soluble vinyl monomer (a1) may be an unneutralized body or a neutralized body (a unit of a water-soluble vinyl monomer salt). Further, it is preferable that the crosslinked polymer (A) is partially or completely neutralized from the viewpoint of reducing the adhesiveness, improving the dispersibility, and the workability in manufacturing the crosslinked polymer (A).

When neutralizing a unit derived from the water-soluble vinyl monomer (a1) contained in the crosslinked polymer (A), generally, an alkali metal hydroxide such as potassium hydroxide, sodium hydroxide or lithium hydroxide, or water is used. An alkaline earth metal hydroxide such as calcium oxide or an aqueous solution thereof may be added to the monomer stage before the polymerization or the hydrogel after the polymerization, but the alkaline cross-linking agent (b2) described later has poor water solubility. Therefore, when the water-soluble vinyl monomer (a1) is polymerized with a high degree of neutralization, even if a predetermined amount of the cross-linking agent (b2) is added, the cross-linking agent (b2) is separated from the monomer aqueous solution and the predetermined cross-linking cannot be performed. The crosslinked polymer (A) may not be obtained, and the degree of neutralization of the water-soluble vinyl monomer (a1) is set to 0 to 30 mol%, and the crosslinking agent (b2) is also contained after the polymerization. If necessary, it is more preferable to add an alkali metal hydroxide to the hydrogel to adjust the degree of neutralization.

When an anionic vinyl monomer {most preferably acrylic acid (salt)} is used as the water-soluble vinyl monomer (a1) of the crosslinked polymer (A), the final degree of neutralization of the anionic vinyl monomer {anionic vinyl The content of the anionic base (mol%)} based on the total number of moles of the anionic group and the anionic base of the monomer is preferably 0 to 90, more preferably 40 to 80, and particularly preferably 60 to 70. Within this range, the impact resistance and discharge characteristics of the negative electrode material are further improved. The anionic base means a neutralized anionic group.

The contents of the water-soluble vinyl monomer (a1) and the vinyl monomer (a2) that becomes (a1) by hydrolysis are (a1), (a2), and alkaline water from the viewpoint of the absorbency of the gelling agent (G). 98.0 to 99.90% by weight, more preferably 99.0 to 99.85% by weight, based on the total weight of the cross-linking agent (b1) that decomposes and the cross-linking agent (b2) that is alkaline and does not hydrolyze. Particularly preferably, it is 99.2 to 99.83% by weight.

As the water-soluble vinyl monomer (a1) and / or the vinyl monomer (a2) which becomes (a1) by hydrolysis, one type may be used alone or two or more types may be used in combination.

Of the water-soluble vinyl monomer (a1) and the vinyl monomer (a2) that becomes (a1) by hydrolysis, (a1) alone or the combination of (a1) and (a2) is preferable from the viewpoint of the discharge characteristics of the alkaline battery. Further preferred is (a1) alone.
When both the water-soluble vinyl monomer (a1) and the vinyl monomer (a2) which becomes (a1) by hydrolysis are used as constituent units, the molar ratio of the units derived from these vinyl monomers {(a1) / (a2)}. Is preferably 75/25 to 99/1, more preferably 85/15 to 98/2, and most preferably 90/10 to 95/5 from the viewpoint of the discharge characteristics of the alkaline battery.

In the crosslinked polymer (A), in addition to the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), another vinyl monomer (a3) copolymerizable with these can be used as a constituent unit. As the other vinyl monomer (a3), one type may be used alone or two or more types may be used in combination.

The other copolymerizable vinyl monomer (a3) is not particularly limited, and the hydrophobic vinyl monomer disclosed in paragraphs [0028] to [0029] of Japanese Patent No. 3648553, JP-A-2003- Hydrophobic vinyl monomers (such as the vinyl monomers disclosed in paragraph [0025] of Japanese Patent Application Laid-Open No. 165883 and paragraph [0058] of JP-A-2005-75982) can be used, and specifically, for example, (i) below. -(Iii) vinyl monomer and the like can be used.
(I) Aromatic ethylenic monomer having 8 to 30 carbon atoms Styrene such as styrene, α-methylstyrene, vinyltoluene and hydroxystyrene, halogen substituted styrene such as vinylnaphthalene and dichlorostyrene and the like.
(Ii) Alkenes (ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.); and alkaziene (butadiene and isoprene, etc.) having 2 to 20 carbon atoms.
(Iii) Alicyclic ethylenic monomer having 5 to 15 carbon atoms Monoethylene unsaturated monomer (pinene, limonene, inden, etc.); and polyethylene vinyl monomer [cyclopentadiene, bicyclopentadiene, etylidene norbornene, etc.] and the like.

The content (mol%) of the other vinyl monomer (a3) unit in the copolymer (A) is the water-soluble vinyl monomer (a1) unit and the hydrolyzable vinyl monomer (a2) unit from the viewpoint of absorption performance and the like. Based on the total number of moles, it is preferably 0 to 5, more preferably 0 to 3, particularly preferably 0 to 2, particularly preferably 0 to 1.5, and other vinyl monomers (from the viewpoint of absorption performance and the like). a3) The unit content is most preferably 0 mol%.

The crosslinked polymer (A) is crosslinked using the crosslinking agent (b). Examples of the cross-linking agent (b) include a cross-linking agent (b1) that is alkaline and hydrolyzes, a cross-linking agent (b2) that is alkaline and does not hydrolyze, and the like.
In the present invention, it is preferable to use (b1) and (b2) together. By using (b1) and (b2) together, the viscosity stability of the gelling agent (G) can be further improved and the alkaline electrolytic solution can be prevented from separating, so that the battery can be discharged for a long period of time. can do. Further, it is preferable because it can be uniformly injected when filling the battery and the bias in the injection amount of the electrolytic solution per battery is small.
Here, the "separation" of the alkaline electrolytic solution means that the gelling agent (G) and the alkaline electrolytic solution cannot maintain a substantially uniform mixed state, and the gelling agent (G) and the alkaline electrolytic solution are separated. It means to do it.

In the crosslinking agent (b1) that hydrolyzes alkaline, "hydrolyzing with alkalinity" means that the unit derived from (b1) in the crosslinked polymer (A) has a hydrolyzable bond, and is hydrolyzable. The bond may be a bond originally possessed in the molecule of the cross-linking agent (b1) {in this case, the cross-linking agent is a cross-linking agent (b11) having a hydrolyzable bond in the molecule}, a cross-linked polymer ( The bond formed by the cross-linking reaction with another monomer {(a1) or (a2)} constituting A) may be hydrolyzed {the cross-linking agent in this case is formed by the cross-linking reaction. The bond is a crosslinkable cross-linking agent (b12)}.
Hydrolytic bonds include ester bonds, amide bonds and the like.

Examples of the cross-linking agent (b11) having a hydrolyzable bond in the molecule include N, N'-methylenebisacrylamide, ethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, and trimethylolpropane tri (). 2 to 10 ethylenic properties in molecules such as meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol trimethyl (meth) acrylate and pentaerythritol tetra (meth) acrylate and polyglycerin (polymerization degree 3 to 13) polyacrylate. Examples thereof include a copolymerizable cross-linking agent having an unsaturated bond.

Examples of the cross-linking agent (b12) in which the bond formed by the cross-linking reaction is hydrolyzable include polyvalent glycidyl compounds (ethylene glycol diglycidyl ether, etc.), polyhydric isocyanate compounds (4,4'-diphenylmethane diisocyanate, etc.), and polyvalent. Examples thereof include reactive cross-linking agents that react with carboxylic acids typified by amine compounds (ethylene diamine and the like) and polyhydric alcohol compounds (glycerin and the like). The reactive cross-linking agent can react with (meth) acrylic acid (salt) to form an ester bond or an amide bond.

Among the cross-linking agents (b1) that hydrolyze with alkali, polyvalent acrylamide compounds and polyvalent acrylate compounds are preferable, and N, is more preferable, from the viewpoint of viscosity stability of the negative electrode material to which the gelling agent (G) is added. N'-methylenebisacrylamide, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate, more preferably N, N'-methylenebisacrylamide, ethylene glycol di ( Meta) acrylates, trimethylolpropane tri (meth) acrylates and ethylene glycol diglycidyl ethers, most preferably N, N'-methylenebisacrylamide and trimethylolpropane tri (meth) acrylates.

The alkaline, non-hydrolyzable cross-linking agent (b2) is a cross-linking agent that does not have a hydrolyzable bond in the molecule and does not generate a hydrolyzable bond by a cross-linking reaction. Examples of such a cross-linking agent (b2) include a cross-linking agent having two or more vinyl ether bonds (b21) and a cross-linking agent having two or more allyl ether bonds (b22). Preferably, it is a cross-linking agent having two or more allyl ether bonds from the viewpoint of reactivity and the like.

Examples of the cross-linking agent (b21) having two or more vinyl ether bonds include ethylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, 1,6-hexanediol divinyl ether, and polyethylene. Examples thereof include glycol divinyl ether (polymerization degree 2 to 5), bisphenol A divinyl ether, pentaerythritol trivinyl ether, sorbitol trivinyl ether and polyglycerin (polymerization degree 3 to 13) polyvinyl ether.

Examples of the cross-linking agent (b22) having two or more allyl ether bonds include a cross-linking agent (b221) having two allyl groups in the molecule and not containing a hydroxyl group, and a cross-linking agent having two allyl groups in the molecule and having a hydroxyl group. (B222), a cross-linking agent having 1 to 5 allyl groups in the molecule and having no hydroxyl group (b223), and a cross-linking agent having 3 to 10 allyl groups in the molecule and having no hydroxyl group. Examples thereof include a cross-linking agent (b224) having 1 to 3 of these. When the molecule contains a hydroxyl group, the compatibility with the vinyl monomer (a1) and / or (a2) {particularly (meth) acrylic acid (salt)} is good, the uniformity of cross-linking is increased, and the gelling agent (G) is used. The long-term stability of the viscosity of the negative electrode material containing the gelling agent (G) is further improved.

Examples of the cross-linking agent (b221) having two allyl groups in the molecule and containing no hydroxyl group include 1,4-cyclohexanedimethanol diallyl ether, alkylene (carbon number 2 to 5) glycol diallyl ether and polyalkylene (carbon number). 2 to 6) Glycol (weight average molecular weight: 100 to 4000) diallyl ether and the like can be mentioned.
Examples of the cross-linking agent (b222) having two allyl groups and 1 to 5 hydroxyl groups in the molecule include glycerin diallyl ether, trimethylolpropane diallyl ether, pentaerythritol diallyl ether, and polyglycerin (degree of polymerization 2 to 5). Examples thereof include diallyl ether and the like.
Examples of the cross-linking agent (b223) having 3 to 10 allyl groups in the molecule and having no hydroxyl group include trimethylolpropanetriallyl ether, glycerintriallyl ether, pentaerythritol tetraallyl ether and tetraallyl oxyethane. Can be mentioned.
Examples of the cross-linking agent (b224) having 3 to 10 allyl groups and 1 to 3 hydroxyl groups in the molecule include pentaerythritol triallyl ether, diglycerin triallyl ether, sorbitol triallyl ether, and polyglycerin (degree of polymerization). 3 to 13) Polyallyl ether and the like can be mentioned.

Two or more kinds of cross-linking agents (b2) that are alkaline and do not hydrolyze may be used in combination.
Among the cross-linking agents (b2), the cross-linking agent (b22) having two or more allyl ether bonds is preferable, and more preferably, the cross-linking agent {(b222) and (b222) having 1 to 5 hydroxyl groups and 2 to 10 allyl groups. b224)}, particularly preferably a cross-linking agent (b224) having 3 to 10 allyl groups and 1 to 3 hydroxyl groups in the molecule, most preferably pentaerythritol triallyl ether and diglycerin triallyl ether and sorbitol tri. Allyl ether. It is preferable to use these cross-linking agents because they have good compatibility with the water-soluble vinyl monomer (a1) and the vinyl monomer (a2) which becomes (a1) by hydrolysis, and efficient cross-linking can be performed.

The content of the cross-linking agent (b1) hydrolyzed by alkali in the cross-linked polymer (A) of the present invention depends on the type of the cross-linking agent (b1) and the average degree of polymerization, but the weight of the cross-linked polymer (A). Is preferably 0.05 to 1% by weight, more preferably 0.1 to 0.8% by weight, and particularly preferably 0.1 to 0.5% by weight. Within this range, excessive separation of the alkaline electrolytic solution can be prevented, so that the long-term discharge characteristics of the battery are further excellent.

The content of the cross-linking agent (b2) that is alkaline and does not hydrolyze in the cross-linking polymer (A) depends on the type of the cross-linking agent (b2), but is preferably 0 based on the weight of the cross-linking polymer (A). It is 0.05 to 1% by weight, more preferably 0.05 to 0.5% by weight, and particularly preferably 0.1 to 0.3% by weight. Within this range, the long-term discharge characteristics of the battery are further excellent.

The weight ratio [(b1) / (b2)] of the cross-linking agent (b1) to the cross-linking agent (b2) in the cross-linked polymer (A) is preferably 1.5 to 5, more preferably 1.7 to 4. Particularly preferably, it is 1.9 to 3. Within this range, excessive separation of the alkaline electrolytic solution can be prevented, so that the long-term discharge characteristics of the battery are further excellent.

The total content of the cross-linking agent (b1) and the cross-linking agent (b2) is preferably 0.10 to 2.0% by weight, more preferably 0.30 to 1. It is 0% by weight, particularly preferably 0.40 to 0.8% by weight. Within this range, excessive separation of the alkaline electrolytic solution can be prevented, so that the long-term discharge characteristics of the battery are further excellent. Further, the stability of the gelling agent (G) is improved, and the long-term stability of the viscosity of the alkaline electrolytic solution containing the gelling agent (G) is further excellent.

The crosslinked polymer (A) is a monomer composition containing a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes (a1) by hydrolysis and a crosslinker (b), which is an organic iodine compound or an organic compound. It can be obtained by polymerizing in the presence of at least one organic typical element compound selected from the group consisting of tellurium compounds, organic antimony compounds and organic bismuth compounds. By adjusting the amount of the organic typical element compound used, the amount of the soluble component in the crosslinked polymer (A) physiological saline and the Mw / Mn of the component having a molecular weight of 100,000 or less among the soluble components can be in a desired range. Can be.

The organic iodine compound, the organic tellurium compound, the organic antimony compound and the organic bismuth compound are not limited as long as they are organic typical element compounds that act as dormant species for radical polymerization, and the organic iodine compounds described as dormant species in WO2011 / 016166, WO2004. The organic tellurium compound described in / 014848, the organic antimony compound described in WO2006 / 001496, the organic bismuth compound described in WO2006 / 062255, and the like can be used. Among them, the organic main group element compound represented by the following general formula (1) is preferable from the viewpoint of reactivity.
These organic typical element compounds may be used alone or in combination of two or more.

R ¹ and R ² in the general formula (1) independently form a hydrogen atom, a saturated hydrocarbon group having 1 to 7 carbon atoms, or at least one non-additive polymerizable double bond or at least one non-additive polymerizable triple bond. It is a monovalent group having 1 to 7 carbon atoms, and R ³ is an n-valent saturated hydrocarbon group having 1 to 7 carbon atoms or at least one non-additive polymerizable double bond or at least one non-additive polymerizable triple. It is an n-valent group having a bond and having 2 to 12 carbon atoms, except that at least one of R ¹ to R ³ in one molecule is the above-mentioned corresponding non-additive polymerizable double bond or at least. A group having one non-additive polymerizable triple bond, n is an integer of 1 to 3, R ¹ and R ² may be bonded to each other when n is 1, and X ¹ is a tellurium element. , A monovalent organic typical element group or an iodo group having an antimonate element or a bismuth element.
In the present specification, the non-additive polymerizable double bond (hereinafter, also simply referred to as non-polymerizable double bond) and the non-additive polymerizable triple bond (hereinafter, also simply referred to as non-polymerizable triple bond) are unsaturated bonds. Of these, the bonds excluding the addition-polymerizable unsaturated bond (additionally polymerizable carbon-carbon double bond and addition-polymerizable carbon-carbon triple bond, respectively), and are non-additive polymerizable double bond and non-additive polymerizable bond. The triple bond includes a carbon-oxygen double bond contained in a carbonyl group, a carbon-nitrogen triple bond contained in a nitrile group, a carbon-carbon double bond constituting an aromatic hydrocarbon, and oxygen constituting a complex aromatic compound. -Nitrogen double bond, carbon-nitrogen double bond, etc., among which carbon-oxygen double bond contained in carbonyl group, carbon-nitrogen triple bond contained in nitrile group and carbon constituting aromatic hydrocarbon -Carbon double bonds are preferred.

When R ¹ and R ² are saturated hydrocarbon groups having 1 to 7 carbon atoms, the saturated hydrocarbon groups having 1 to 7 carbon atoms are linear saturated hydrocarbon groups having 1 to 7 carbon atoms (methyl group, ethyl). Group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, etc.) and branched saturated hydrocarbon group with 1 to 7 carbon atoms (i-propyl group, isobutyl group, s-butyl group, t) -Butyl group, isopentyl group, neopentyl group, t-pentyl group, 1-methylbutyl group, isohexyl group, s-hexyl group, t-hexyl group, neohexyl group, heptyl group, etc.). Among them, a linear saturated hydrocarbon group having 1 to 5 carbon atoms is preferable from the viewpoint of solubility and polymerizable property, and a linear saturated hydrocarbon group having 1 to 3 carbon atoms is more preferable.

When R ¹ and R ² are monovalent groups having at least one non-polymerizable double bond or at least one non-polymerizable triple bond and having 1 to 7 carbon atoms, a carboxy (salt) group is preferable. (1, carbon number, carbon-oxygen double bond), phenyl group (6 carbon number, non-polymerizable carbon-carbon double bond), cyano group (1, carbon number, carbon-nitrogen triple bond), cyanomethyl group (number of carbon number) 2. Carbon-nitrogen triple bond), cyanoethyl group (3 carbons, carbon-nitrogen triple bond), cyanopropyl group (4 carbons, carbon-nitrogen triple bond), cyanobutyl group (5 carbons, carbon-nitrogen triple bond) ), Cyanopentyl group (6 carbons, carbon-nitrogen triple bond), cyanohexyl group (7 carbons, carbon-nitrogen triple bond), carboxymethyl group (2 carbons, carbon-oxygen double bond), carboxyethyl Group (3 carbons, carbon-oxygen double bond), carboxypropyl group (4 carbons, carbon-oxygen double bond), carboxybutyl group (5 carbons, carbon-oxygen double bond), carboxypentyl group (4 carbons, carbon-oxygen double bond) 6 carbons, carbon-oxygen double bond), carboxyhexyl group (7 carbons, carbon-oxygen double bond), benzyl group (7 carbons, non-polymerizable carbon-carbon double bond), methoxycarbonyl group (7 carbons, non-polymerizable carbon-carbon double bond) Carbon number 2, carbon-oxygen double bond), ethoxycarbonyl group (carbon number 3, carbon-oxygen double bond), propyloxycarbonyl group (carbon number 4, carbon-oxygen double bond), butyloxycarbonyl group (carbon number 4, carbon-oxygen double bond) 5 carbons, carbon-oxygen double bond), pentyloxycarbonyl group (6 carbons, carbon-oxygen double bond), hexyloxycarbonyl group (7 carbons, carbon-oxygen double bond), hydroxyethoxycarbonyl group (3 carbons, carbon-oxygen double bond), hydroxypropyloxycarbonyl group (4 carbons, carbon-oxygen double bond), hydroxybutyloxycarbonyl group (5 carbons, carbon-oxygen double bond), hydroxy Examples thereof include a pentyloxycarbonyl group (6 carbons, carbon-oxygen double bond) and a hydroxyhexyloxycarbonyl group (7 carbons, carbon-oxygen double bond), and more preferably, a carboxy (salt) group, It is a cyano group, a carboxymethyl group and a carboxyethyl group.
Examples of the salt include alkali metal (lithium, sodium, potassium, etc.) salt, alkaline earth metal (magnesium, calcium, etc.) salt, ammonium (NH ₄ ) salt, and the like. Of these salts, alkali metal salts and ammonium salts are preferable, and alkali metal salts are more preferable, and sodium salts are particularly preferable, from the viewpoint of the amount of absorption of the 40 wt% potassium hydroxide aqueous solution.

R ³ is an n-valent saturated hydrocarbon group having 1 to 7 carbon atoms or an n-valent group having at least one non-polymerizable double bond or at least one non-polymerizable triple bond and having 2 to 12 carbon atoms. , N is an integer of 1 to 3.

Among the n-valent saturated hydrocarbon groups having 1 to 7 carbon atoms represented by R ³ , the monovalent saturated hydrocarbon group having 1 to 7 carbon atoms is a linear saturated hydrocarbon group having 1 to 7 carbon atoms. (Methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, heptyl group, etc.) and branched saturated hydrocarbon group with 1 to 7 carbon atoms (i-propyl group, isobutyl). Group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, t-pentyl group, 1-methylbutyl group, isohexyl group, s-hexyl group, t-hexyl group, neohexyl group, isoheptyl group, etc.) Be done.
Among the n-valent saturated hydrocarbon groups having 1 to 7 carbon atoms represented by R ³ , the divalent saturated hydrocarbon group having 1 to 7 carbon atoms is a divalent linear saturated hydrocarbon group having 1 to 7 carbon atoms. Hydrocarbon groups (methylene group, ethylene group, propylene group, butylene group, penten group, hexene group, heptene group, etc.) and divalent branched saturated hydrocarbon group with 1 to 7 carbon atoms (isopropylene group, isobutylene group, s) -Butylene group, t-butylene group, isopentylene group, neopentylene group, t-pentylene group, 1-methylbutylene group, isohexylene group, s-hexylene group, t-hexylene group, neohexylene group, isoheptylene group, etc.).
Among the n-valent saturated hydrocarbon groups having 1 to 7 carbon atoms represented by R ³ , the trivalent saturated hydrocarbon group having 1 to 7 carbon atoms includes a methine group and the like.
Of the n-valent saturated hydrocarbon groups represented by R ³ having 1 to 7 carbon atoms, a methyl group, a methylene group and a methine group are preferable, and a methyl group and a methylene group are more preferable.

Of the n-valent groups in which R ³ has at least one non-polymerizable double bond or at least one non-polymerizable triple bond and has 2 to 12 carbon atoms, the monovalent groups are R ¹ and R ² . The same groups as the exemplified groups are mentioned, and so are the preferred ones.
When R ³ is a divalent group having at least one non-polymerizable double bond or at least one non-polymerizable triple bond and having 2 to 12 carbon atoms, a preferred group is a benzenediyl group (6 carbon atoms). , Non-polymerizable carbon-carbon double bond), 1-methoxycarbonyl-carbonyloxyethylene oxycarbonyl group (6 carbons, oxygen-oxygen double bond) and carbonyloxyethylene carbonyl group (4 carbons, oxygen-oxygen di) Double bond) and the like.
When R ³ is a trivalent group having at least one non-polymerizable double bond or at least one non-polymerizable triple bond and having 2 to 12 carbon atoms, a benzenetriyl group (carbon number) is preferable. 6. Non-polymerizable carbon-carbon double bond) and 2-carbonyloxy-carbonyloxypropylene carbonyl group (5 carbon atoms, oxygen-oxygen double bond) and the like.

When n is 1, R ¹ and R ² may be bonded to each other, and preferred groups having a ring structure formed by bonding R ¹ and R ² to each other are the γ-butyrolactonyl group and the group. Examples include a fluorenyl group. The group in which R ¹ and R ² are bonded to each other to form a ring structure contains a carbon atom to which R ¹ and R ² are bonded in the ring structure.

X ¹ is a monovalent main group organic element group or an iodine group having a tellurium element, an antimony element or a bismuth element, preferably a methylteranyl group, a dimethylstibanyl group, a dimethylbismutanyl group and an iodine group, and more preferably. Methylteranyl groups and iodine groups, particularly preferred are iodine groups.

Among the organic typical element compounds represented by the general formula (1), those having an iodine group include 2-iodopropionitrile, 2-iodo-2-methylpropionitrile, α-iodobenzyl cyanide, and 2 -Iodine propionate amide, ethyl-2-iodo-2-methylpropionate, 2-iodo-2-methylpropionate methyl, 2-iodo-2-methylpropionate propyl, 2-iodo-2-methylpropionic acid Butyl, 2-iodo-2-methylpropionic acid pentyl, 2-iodo-2-methylpropionic acid hydroxyethyl, 2-iodo-2-methylpropionic acid (salt), 2-iodopropionic acid (salt), 2-iodine Acetic acid (salt), 2-iodoacetate methyl, 2-iodoacetate ethyl, 2-iodopentanoate ethyl, 2-iodopentanoate methyl, 2-iodopentanoic acid (salt), 2-iodohexanoic acid (salt), 2 -Iodine heptanic acid (salt), diethyl 2,5-diodoadipine, 2,5-diodoadipine acid (salt), dimethyl 2,6-diiodo-heptane diate, 2,6-diiodo-heptane diic acid (Salt), α-iodine-γ-butyrolactone, 2-iodoacetophenone, benzyliodide, 2-iodo-2-phenylacetic acid (salt), 2-iodo-2-phenylacetate methyl, 2-iodo-2-phenyl Ethyl acetate, 2-iodo-2- (4'-methylphenyl) ethyl acetate, 2-iodo-2-phenylacetic acid-hydroxyethyl, 2-iodo-2- (4'-nitrophenyl) ethyl acetate, 4-nitro Benzyliodide, (1-iodoethyl) benzene, iododiphenylmethane, 9-iodo-9H-fluorene, p-xylylene diiodide, 1,4-bis (1'-iodoethyl) benzene, ethylene glycol bis (2-methyl- 2-iodo-propinate), tris (2-methyl-iodopropionic acid) glycerol, 1,3,5-tris (1'-iodoethylbenzene), ethylene glycol bis (2-iodo-2phenylacetate) and the like. ..

Among the organic typical element compounds represented by the general formula (1), those having a tellurium element include 2-methylteranylpropionitrile, 2-methyl-2-methylteranylpropionitrile, and α-methyltera. Nylbenzyl cyanide, 2-methylteranylpropionic acid amide, ethyl-2-methyl-2-methylteranyl-propinate, methyl 2-methyl-methylteranylpropionate, propyl 2-methyl-methylteranylpropionate, 2- Butyl methyl-methylteranylpropionate, pentyl 2-methyl-methylteranylpropionate, hydroxyethyl 2-methyl-methylteranylpropionate, 2-methyl-2-methylteranyl-propionic acid (salt), 2-methyltera Nylpropionic acid (salt), 2-methylteranylacetic acid (salt), 2-methylteranylacetate methyl, 2-methylteranylacetate ethyl, 2-methylteranylpentanoate ethyl, 2-methylteranylpentanoate methyl, 2-methylteranyl Pentanoic acid (salt), 2-methylteranylhexanoic acid (salt), 2-methylteranylheptanic acid (salt), diethyl 2,5-dimethylteranyladipate, 2,5-dimethylteranyladipate (salt) ), 2,6-dimethylteranyl-heptanediate dimethyl, 2,6-dimethylteranyl-heptanedioic acid (salt), α-methylteranyl-γ-butyrolactone, 2-methylteranylacetophenone, 2-methylteranyl-2 -Phenylacetic acid (salt), 2-methylteranyl-2-methylmethylphenylacetate, 2-methylteranyl-2-phenylacetate ethyl, 2-methylteranyl-2- (4'-methylphenyl) ethyl acetate, 2-methylteranyl-2-phenyl -Hydroxyethyl acetate, 2-methylteranyl-2- (4'-nitrophenyl) ethyl acetate, (1-methylteranylethyl) benzene, methylteranyldiphenylmethane, 9-methylteranyl-9H-fluorene, 1,4-bis ( 1'-Methylteranylethyl) benzene, ethylene glycol bis (2-methyl-2-methylteranyl-propinate), tris (2-methyl-methylteranylpropionic acid) glycerol, 1,3,5-tris (1'- Methylteranyl ethylbenzene), ethylene glycol bis (2-methylteranyl-2 phenylacetate) and the like.

Among the organic typical element compounds represented by the general formula (1), those having an antimony element include 2-dimethylstibanylpropionitrile, 2-methyl-2-dimethylstibanylpropionitrile, and α-dimethylsti. Vanylbenzylchanide, 2-dimethylstibanylpropionic acid amide, ethyl-2-methyl-2-dimethylstibanyl-propinate, 2-methyl-dimethylstibanylpropionic acid, 2-methyl-dimethylstivanylpropionic acid propyl, Butyl 2-methyl-dimethylstivanylpropionic acid, pentyl 2-methyl-dimethylstivanylpropionic acid, hydroxyethyl 2-methyl-dimethylstivanylpropionic acid, 2-methyl-2-dimethylstivanyl-propionic acid (salt), 2-Dimethylstibanylpropionic acid (salt), 2-dimethylstivanylacetic acid (salt), 2-dimethylstivanylacetic acid methyl, 2-dimethylstivanylacetate ethyl, 2-dimethylstivanylpentanoate ethyl, 2-dimethylsti Methyl vanylpentate, 2-dimethylstibanylpentanoic acid (salt), 2-dimethylstivanylhexanoic acid (salt), 2-dimethylstivanylheptanoic acid (salt), diethyl 2,5-didimethylstivanyladipate, 2,5-Didimethylstivanyl adiponic acid (salt), 2,6-didimethylstivanyl-dimethyl heptane, 2,6-didimethylstivanyl-heptanedioic acid (salt), α-dimethylstivanyl- γ-Butyrolactone, 2-dimethylstivanylacetophenone, 2-dimethylstivanyl-2-phenylacetic acid (salt), 2-dimethylstivanyl-2-phenylacetate methyl, 2-dimethylstivanyl-2-phenylacetate ethyl, 2 -Dimethylstibanyl-2- (4'-methylphenyl) ethyl acetate, 2-dimethylstivanyl-2-phenylacetate-hydroxyethyl, 2-dimethylstibanyl-2- (4'-nitrophenyl) ethyl acetate, ( 1-Dimethylstivanylethyl) benzene, dimethylstivanyldiphenylmethane, 9-dimethylstivanyl-9H-fluorene, 1,4-bis (1'-dimethylstivanylethyl) benzene, ethyleneglycolbis (2-methyl-2-) Dimethylstivanyl-propinate), tris (2-methyl-dimethylstivanylpropionic acid) glycerol, 1,3,5-tris (1'-dimethylstivanylethylbenzene) and ethylene glycol bis (2-di) Methylstivanyl-2 phenylacetate) and the like.

Among the organic typical element compounds represented by the general formula (1), those having a bismuth element include 2-dimethylbismutanylpropionitrile, 2-methyl-2-dimethylbismutanylpropionitrile, and α-. Dimethylbismutanylbenzyl cyanide, 2-dimethylbismutanylpropionic acid amide, ethyl-2-methyl-2-dimethylbismutanylpropinate, 2-methyl-dimethylbismutanylpropionic acid methyl, 2-methyl-dimethyl Propyl bismutanylpropionate, butyl 2-methyl-dimethylbismutanylpropionate, pentyl 2-methyl-dimethylbismutanylpropionate, hydroxyethyl 2-methyl-dimethylbismutanylpropionate, 2-methyl-2- Dimethylbismutanylpropionic acid (salt), 2-dimethylbismutanylpropionic acid (salt), 2-dimethylbismutanylacetic acid (salt), 2-dimethylbismutanylacetic acid methyl, 2-dimethylbismutanylacetate ethyl , 2-Dimethylbismutanylpentanate ethyl, 2-dimethylbismutanylpupanate methyl, 2-dimethylbismutanylpupanoic acid (salt), 2-dimethylbismutanylhexanoic acid (salt), 2-dimethyl Bismutanylheptanoic acid (salt), 2,5-didimethylbismutanyladipate diethyl, 2,5-didimethylbismutanyladiponic acid (salt), 2,6-didimethylbismutanylheptanidiate dimethyl , 2,6-didimethylbismutanyl heptaniic acid (salt), α-dimethylbismutanyl γ-butyrolactone, 2-dimethylbismutanyl acetophenone, 2-dimethylbismutanyl 2-phenylacetic acid (salt), 2 -Dimethylbismutanyl 2-Methyl phenylacetate, 2-dimethylbismutanyl 2-Ethyl phenylacetate, 2-dimethylbismutanyl 2- (4'-methylphenyl) Ethyl acetate, 2-dimethylbismutanyl 2-phenyl Acetate-hydroxyethyl, 2-dimethylbismutanyl 2- (4'-nitrophenyl) ethyl acetate, (1-dimethylbismutanylethyl) benzene, dimethylbismutanyldiphenylmethane, 9-dimethylbismutanyl 9H-fluorene, 1,4-bis (1'-dimethylbismutanylethyl) benzene, ethylene glycol bis (2-methyl-2-dimethylbismutanylpropinate), tris (2-methyl-dimethylbismutanylpropionic acid) glycerol, 1,3,5-Tris (1'-dimethylbismuta) Nylethylbenzene) and ethylene glycol bis (2-dimethylbismutanyl 2 phenylacetate) and the like.

Of these, 2-iodo-2-methylpropionitrile, ethyl-2-iodo-2-methylpropionate, 2-iodo-2-methylpropionic acid (salt), and 2-iodoacetic acid (salts) are preferred. Salt), Methyl 2-iodoacetate, diethyl 2,5-diiodoadipate, 2,5-diodeadipic acid, ethylene glycol bis (2-methyl-2-iodo-propinate), ethylene glycol bis (2-iodo) -2phenylacetate), 2-methylteranylpropionitrile, ethyl-2-methyl-2-methylteranyl-propinate, diethyl 2,5-bismethylteranyl adipate, ethyleneglycolbis (2-methyl-2-methylteranyl) -Propinate), ethylene glycol bis (2-methylteranyl-2phenylacetate), 2-dimethylstivanylpropionitrile, ethyl-2-methyl-2-dimethylstivanyl-propinate and 2-dimethylbismutanylpropionitrile and It is ethyl-2-methyl-2-dimethylbismutanylpropinate.

The amount of the organic main group element compound used is preferably 0.0005 to 0.1 based on the weights of the above-mentioned monomers (a1), (a2), cross-linking agent (b) and, if necessary, other monomers (a3). By weight%, more preferably 0.005 to 0.05% by weight. Within this range, the amount of the soluble component in physiological saline and the Mw / Mn of the component having a molecular weight of 100,000 or less among the soluble components can be obtained in an appropriate range, and the gelling agent (G) can be used. The viscosity of the added negative electrode material becomes appropriate, the zinc powder does not settle, and the impact resistance and discharge characteristics are good.

A method for polymerizing a monomer composition containing a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) to be hydrolyzed (a1) and a cross-linking agent (b) in the presence of the above-mentioned organic typical element compound. A known polymerization method such as aqueous solution polymerization, suspension polymerization, lumpy polymerization, reverse phase suspension polymerization and emulsification polymerization can be applied to the above. In these polymerization methods, the organic main group element compound may be present in the monomer or the monomer aqueous solution, or may be added at the time of adding the initiator or the like to the monomer solution or the like.

Among these polymerization methods, aqueous solution polymerization, suspension polymerization, reverse phase suspension polymerization and emulsion polymerization are preferable from the viewpoint of discharge characteristics and impact resistance, and aqueous solution polymerization, reverse phase suspension polymerization and emulsion polymerization are more preferable. Particularly preferred are aqueous solution polymerization and reverse phase suspension polymerization. Known polymerization initiators, chain transfer agents and / or solvents and the like can be used for these polymerizations.

The method of polymerizing by aqueous solution polymerization, suspension polymerization, reverse phase suspension polymerization and emulsification polymerization may be a known method, for example, a method of polymerizing using a radical polymerization initiator, a method of irradiating with radiation, ultraviolet rays or electron beams. Can be mentioned.

When a radical polymerization initiator is used, the initiator may be an azo compound [azobisisobutyronitrile, azobisisobutyronitrile, 4,4'-azobis (4-cyanovaleric acid), 2,2'-. Azobis [2-methyl-N- (2-hydroxyethyl) propionamide, 2,2'-azobis (2-amidinopropane) hydrochloride, etc.], inorganic peroxides [hydrogen peroxide, potassium persulfate, ammonium persulfate, etc.] Sodium persulfate, etc.], organic peroxide [di-t-butyl peroxide, cumenehydroperoxide, etc.], redox initiator [alkali metal salt sulfite or bicarbonate, ammonium sulfite, ammonium bicarbonate, L- A combination of a reducing agent such as ascorbic acid and a peroxide such as a persulfate of an alkali metal salt, ammonium persulfate, and a hydrogen peroxide solution] and the like can be mentioned. These may be used alone or in combination of two or more.

The polymerization temperature varies depending on the type of initiator used, but is preferably −10 ° C. to 100 ° C., more preferably −10 ° C. to 80 ° C. from the viewpoint of increasing the degree of polymerization of the polymer. The amount of the initiator is also not particularly limited, but the degree of polymerization of the polymer is based on the total weight of the vinyl monomer (a1), (a2), the cross-linking agent (b) and other monomers (a3) used if necessary. From the viewpoint of increasing the value, 0.000001 to 3.0% by weight is preferable, and 0.000001 to 0.5% by weight is more preferable.

In the case of aqueous solution polymerization, the polymerization concentration of the monomer varies depending on other polymerization conditions, but the water-soluble vinyl monomer (a1) and the vinyl monomer (a2) which becomes (a1) by hydrolysis have a high polymerization concentration. Then, pseudo-crosslinking (self-crosslinking) of the monomer itself is likely to occur in parallel with the polymerization reaction, which causes a decrease in the absorption amount and a decrease in the average degree of polymerization of the polymer, and it is difficult to control the temperature during the polymerization. The polymerization concentration is preferably 10 to 40% by weight, more preferably 10 to 30% by weight, because it tends to cause a decrease in the amount of the polymer and an increase in the oligomer component. The polymerization temperature is preferably −10 to 100 ° C., more preferably −10 to 80 ° C. The amount of dissolved oxygen at the time of polymerization is preferably 0 to 2 ppm (2 × 10 ^-4 % by weight or less), more preferably 0 to 0.5 ppm (0.5 ×), although it depends on the amount of the radical initiator added and the like. ^10-4 % by weight or less). Within these ranges, the crosslinked polymer (A) having a high degree of polymerization can be produced.

When a monomer having an acid group such as (meth) acrylic acid is used, the degree of neutralization of the acid group at the time of polymerization is such that a predetermined amount of the cross-linking agents (b1) and (b2) can be completely dissolved in the monomer aqueous solution. However, there is no particular limitation, but compared to (b1), (b2) has poor water solubility, and in particular, the solubility of the monomer having an acid group in an aqueous solution is extremely low, and even if a predetermined amount of (b2) is added (b2). ) May separate from the aqueous monomer solution and the predetermined cross-linking may not be possible. Therefore, the degree of neutralization of the monomer having an acid group at the time of polymerization is 0 to 30 mol%, and if necessary, further neutralization is performed after the polymerization. It is preferable to polymerize in an unneutralized state, and more preferably neutralize after polymerization if necessary. Further, when the monomer having an acid group is polymerized under the same conditions, the degree of polymerization tends to increase when the degree of polymerization is low. Therefore, in order to increase the degree of polymerization of the polymer, the degree of neutralization is low. It is preferable to carry out polymerization.

The reverse phase suspension polymerization method is a polymerization method in which an aqueous solution of a monomer is suspended / dispersed in a hydrophobic organic solvent typified by hexane, toluene, xylene, etc. in the presence of a dispersant and polymerized. Also in this polymerization method, the monomer concentration in the monomer aqueous solution is preferably 10 to 40% by weight, more preferably 10 to 30% by weight, as described above. Within this range, the crosslinked polymer (A) having a high degree of polymerization can be produced.

Regarding this reverse phase suspension polymerization method, a dispersant may be used at the time of polymerization. Examples of the dispersant include sorbitan fatty acid esters such as sorbitan monostearate ester having an HLB (Hydrophile-Lipophile Balance) value of 3 to 8, glycerin fatty acid esters such as glycerin monostearic acid ester, and sucrose distearate ester. Hydrophilicity in molecules such as surfactants such as sugar fatty acid esters, maleides of ethylene / acrylic acid copolymers, maleides of ethylene / vinyl acetate copolymers, styrene sulfonic acid (salt) / styrene copolymers, etc. A polymer dispersant (hydrophilic group; 0.1 to 20% by weight, weight average molecular weight; 1,000 to 1,000,000) which has a group and is soluble in a solvent for dispersing the aqueous monomer solution is used. As an example, when a polymer dispersant is used as the dispersant, it is easier to adjust the size of the suspended particles of the monomer aqueous solution in the solvent, and the water-containing crosslinked polymer (A) having the required particle size is contained. It is preferable because it can produce a gel.

From the viewpoint of the discharge characteristics of the alkaline battery, the amount of the dispersant used is preferably 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on the weight of the hydrophobic organic solvent. The weight ratio (W / O ratio) of the aqueous monomer solution and the hydrophobic organic solvent in the reverse phase suspension polymerization is preferably 0.1 to 2.0, more preferably 0.3 to 1.0. Within these ranges, the particle size of the crosslinked polymer (A) can be further adjusted.

In the production of the crosslinked polymer (A), the average degree of polymerization of the polymer when the polymer is produced under exactly the same conditions except that the crosslinking agent (b) is not used is preferably 5,000 to 1,000,000. It is more preferable to carry out the polymerization under the conditions that are, more preferably 10,000 to 1,000,000.
When the polymerization is carried out under the condition that the average degree of polymerization is 5,000 or more, the viscosity of the high-concentration alkaline aqueous solution to which the gelling agent (G) is added is lowered and / or the spinnability is increased by using an appropriate amount of a cross-linking agent. It is possible to prevent the increase. The above-mentioned average degree of polymerization can be measured in the same manner as the method for measuring the weight average molecular weight and the number average molecular weight of the soluble component of the crosslinked polymer (A) in physiological saline, which will be described later.

In the present invention, the crosslinked polymer (A) obtained by aqueous solution polymerization, reverse phase suspension polymerization or the like is obtained as a gel containing water (water-containing gel). The hydrous gel is used as a gelling agent (G) after being dried. Regarding the method of drying the hydrogel, in the case of aqueous solution polymerization, the hydrogel is subdivided to some extent with a meat chopper or a cutter-type coarse crusher (the level of subdivision is about 0.5 to 20 mm square) or noodles, if necessary. After neutralizing the hydrous gel by adding an aqueous solution of alkali metal hydroxide, etc., air-permeable drying (a hydrogel is laminated on a punching metal or a screen, and hot air at 50 to 150 ° C. is forcibly aerated to dry it. Examples of methods such as aeration drying (a water-containing gel is placed in a container, hot air is aerated and circulated to dry, and the gel is further subdivided and dried by a machine such as a rotary kiln). Among these, air-permeable drying is preferable because it can perform efficient drying in a short time. On the other hand, in the case of reverse phase suspension polymerization, the method for drying the hydrous gel is that the polymerized hydrogel and the organic solvent are solid-liquid separated by a method such as decantation, and then dried under reduced pressure (decompression degree; about 100 to 50,000 Pa). Alternatively, it is common to perform aeration drying.

As another drying method of the hydrous gel in the aqueous solution polymerization, for example, there is a contact drying method in which the hydrous gel is compression-stretched on a drum dryer and dried. It is necessary to prepare a thin film of hydrogel on a drum or the like. However, since the material of a commercially available drum dryer is generally made of a metal having a lower ionization tendency than zinc such as iron, chromium and nickel, the frequency of contact with the drum metal surface per water-containing gel becomes extremely high. Further, since the hydrous gel is a hydrogel containing poly (meth) acrylic acid (salt) or the like, the content of metal elements having a lower ionization tendency is higher than that of zinc eluted in the gel. Further, since the contact frequency between the water-containing gel and the drum is extremely high and the water-containing gel has high adhesiveness, it is necessary to bring a knife-like object into contact with the drum dryer to peel the dried product from the drum dryer. And due to the mechanical wear of the knife, the metal surface of the drum or knife wears and the metal gets mixed into the dried material. As described above, when a contact drying method such as a drum dryer is used, metal ions and metal powder are likely to be mixed in the gelling agent (G), and the metal having a lower ionization tendency than zinc (standard electrode potential is higher than that of zinc). It is a low metal and contains a considerably large amount of (metal) ions and metal powders that can be represented by atomic symbols such as Cr, Fe, Ni, Sn, Pb, Cu, Hg, and Ag. When these gelling agents (G) are used as a gelling agent (G) for an alkaline battery, the zinc powder in the battery forms a battery with a metal ion or a metal powder having a lower ionization tendency than zinc. Hydrogen gas is generated by electrolysis, which raises the pressure inside the battery, which may cause the outflow of the alkaline electrolyte and, in the worst case, damage to the battery. Further, the thin film-like dried product obtained by compressing and stretching the hydrogel on a drum dryer or the like and drying it is pulverized and the particles are scaly even if the particle size of the dried product is adjusted to a desired particle size. Therefore, the strength is much weaker than that of the crushed block-shaped dried product by the air-permeable drying method or the aeration drying method. The gel is destroyed and the gel becomes smaller. Therefore, it is preferable not to use a contact drying method such as a drum dryer.

In the present invention, the drying temperature at the time of drying the hydrogel varies depending on the dryer used, the drying time, and the like, but is preferably 50 to 150 ° C, more preferably 80 to 130 ° C. When the drying temperature is 50 ° C. or lower, it takes a long time to dry, and the productivity is significantly lowered. When the temperature is 50 ° C. or higher, it does not take a long time to dry and is efficient. The drying time also varies depending on the model of the dryer used, the drying temperature and the like, but is preferably 5 to 300 minutes, more preferably 5 to 120 minutes.

The dried product of the crosslinked polymer (A) thus obtained is pulverized and pulverized, if necessary. The crushing method may be a known method, and can be performed by, for example, an impact crusher (pin mill, cutter mill, skillel mill, ACM pulperizer, etc.) or an air crusher (jet crusher, etc.).

For the powdered crosslinked polymer (A), a dry powder having a desired particle size can be collected by using a flue machine (vibration flue machine, centrifugal flue machine, etc.) equipped with a screen, if necessary.

In the present invention, it is preferable to remove the mixed metal powder such as iron by using a magnetic iron remover at an arbitrary stage after drying. However, even if iron is removed with a high degree of precision using an iron remover, it is difficult for the iron remover to remove non-magnetic metals, and magnetic metals are also contained inside the dried polymer particles. Since it is not possible to remove magnetism or particles adhering to dried particles, it is desirable to give due consideration to the production equipment so that these metals do not get mixed in from the beginning.

The amount of the soluble component of the crosslinked polymer (A) in the physiological saline solution (0.9% by weight sodium chloride aqueous solution) in the present invention is 5 to 20% by weight, preferably 5 based on the weight of (A). It is ~ 15, more preferably 5 ~ 10.
When the amount of the soluble component is in this range, the viscosity of the alkaline electrolytic solution to which the gelling agent (G) is added is in a suitable range, and the drainage of the negative electrode material is improved, so that a battery with stable quality can be manufactured. Moreover, since it becomes possible to prevent the zinc powder from settling in the negative electrode material, it is possible to produce a battery having excellent discharge characteristics over time. When the amount of the soluble component exceeds 20% by weight, the alkaline electrolytic solution to which the gelling agent (G) is added exhibits spinnability, the drainage of the negative electrode material is remarkably deteriorated, and the filling amount varies, so that the quality of the battery is stable. do not do. When the amount of the soluble component is less than 5% by weight, the viscosity of the alkaline electrolytic solution to which the gelling agent (G) is added becomes low, and the zinc powder is settled, so that the impact resistance and the discharge characteristics are deteriorated.

The amount of the soluble component of the crosslinked polymer (A) in physiological saline can be measured by the following method.
<Method of measuring the amount of soluble component in physiological saline of (A)>
1 g of the gelling agent (G) is precisely weighed (the weighed value is S0), added to 250 ml of physiological saline (0.9 wt% sodium chloride aqueous solution), stirred for 3 hours, and then the swollen gel is obtained. Remove with filter paper (Filter Paper No. 1 qualitative filter paper manufactured by Advantech). The filtrate obtained after removing the gel is used as an extract of soluble components.
About 25 ml of the extract of the soluble component obtained by the above method is placed in an eggplant-shaped flask having a capacity of 50 ml, and water is distilled off under reduced pressure using an evaporator. About 25 ml of the extract is added to the eggplant-shaped flask, and the operation of distilling off the water under reduced pressure is repeated to distill off the water for the entire amount of the extract. Next, the eggplant-shaped flask containing the residue is allowed to stand in a circulating air dryer at 130 ° C. for 90 minutes, and then allowed to stand in a desiccator for 15 minutes to cool the eggplant-shaped flask to room temperature. After cooling, the weight of the residue (S1) in the eggplant-shaped flask is measured. The same operation is performed on the same amount of physiological saline as the extract used in the previous operation, and the weight of the residue after cooling (S2) is measured. The weight of the residue after cooling is obtained by subtracting the weight of the eggplant-shaped flask measured in advance from the weight of the eggplant-shaped flask containing the residue after cooling.
Using (S0), (S1) and (S2) obtained above, the amount of soluble component is calculated from the following formula.
Amount of soluble component (%) = (S1-S2) ÷ S0 × 100

The weight average molecular weight (hereinafter abbreviated as Mw) with respect to the number average molecular weight (hereinafter abbreviated as Mn) of the component having a molecular weight of 100,000 or less among the components soluble in the physiological saline of the crosslinked polymer (A) in the present invention. The ratio (Mw / Mn) is 4.0 to 6.0, preferably 4.0 to 5.5, and more preferably 4.0 to 5.0.
When Mw / Mn of the component having a molecular weight of 100,000 or less among the soluble components is in this range, the viscosity of the alkaline electrolytic solution to which the gelling agent (G) is added is in a suitable range, and the negative electrode material drains well. Therefore, it is possible to manufacture a battery with stable quality and prevent the zinc powder from settling in the negative electrode material, so that it is possible to produce a battery having excellent discharge characteristics over time. When the Mw / Mn of the soluble component having a molecular weight of 100,000 or less exceeds 6.0, the amount of the low molecular weight component in the soluble component increases, so that the viscosity of the alkaline electrolytic solution to which the gelling agent (G) is added becomes low. , Impact resistance and discharge characteristics deteriorate due to sedimentation of zinc powder. When Mw / Mn is less than 4.0, the amount of the high molecular weight component in the soluble component becomes large, so that the alkaline electrolytic solution to which the gelling agent (G) is added has a spinnability, and the negative electrode material runs out. However, the quality of the battery is not stable because the filling amount varies significantly.

Among the soluble components of the crosslinked polymer (A) in physiological saline, Mw and Mn having a molecular weight of 100,000 or less are chromatographed by the gel permeation chromatography method (GPC method) under the following conditions. It is obtained by obtaining grams and calculating Mw and Mn in a section having a molecular weight of 100,000 or less.
Equipment: "HLC-8320" (manufactured by Tosoh Corporation)
Column: "TSK Guard volume PWXL" (1), "TSKgel G60000 PWXL, TSKgel G3000 PWXL" (1) (all manufactured by Tosoh Corporation) connected 1 each Mobile phase: 0.5 wt% sodium acetate Aqueous solution / methanol = 7/3 (volume ratio)
Measuring solution: Injection amount of extract solution of soluble component in the above-mentioned method for measuring the amount of soluble component: 50 μl
Flow rate: 1.0 ml / min Measurement temperature: 40 ° C
Detector: Refractive index detector Reference material: Standard polyethylene oxide

The gelling agent (G) of the present invention is used for the purpose of improving the fluidity at the time of filling a mixture of negative electrode substances other than the crosslinked polymer (A), as long as it does not cause any problems in workability and battery characteristics. Other additives may be included.
Examples of other additives include thickeners, vibration and impact resistance improvers, discharge characteristic improvers and the like.

Examples of the thickener include CMC (carboxymethyl cellulose), natural gum (guar gum, etc.), uncrosslinked poly (meth) acrylic acid (salt), water-soluble resin such as polyvinyl alcohol, and the like. The particle size of the thickener to be added as necessary is not particularly limited, but the volume average particle size of the dried product is preferably 0.1 to 100 μm (further, 0.1 to 50 μm). Within this range, handling is easy, such as when mixing with an alkaline electrolytic solution and filling the negative electrode container of a battery.

As the vibration and impact resistance improving agent, oxides, hydroxides, sulfides and the like of metal elements selected from the group consisting of titanium, indium, tin and bismuth can be used.
Examples of the discharge characteristic improving agent include known compounds such as silicon dioxide and potassium silicate.
When the other additives are contained, the content is preferably 0 to 5.0% by weight, more preferably 0 to 3.0% by weight, based on the weight of the alkaline electrolytic solution.

Other additives should be added at any stage {in the cross-linked polymer (A) manufacturing process, the polymerization step, the shredding step, the drying step, the pulverization step, the surface cross-linking step and / or before and after these steps}. Can be done.

The absorption amount of the 40% by weight potassium hydroxide aqueous solution of the gelling agent (G) of the present invention is preferably 40 to 70 g / g, more preferably 42 to 65 g / g, and particularly preferably 45 to 60. Within this range, excessive separation of the alkaline electrolytic solution can be prevented, and the long-term discharge characteristics of the battery are further excellent. In addition, the impact resistance and productivity (process simplification) of alkaline batteries are excellent.

The absorption amount of the 40% by weight potassium hydroxide aqueous solution of the gelling agent (G) of the present invention is measured by the following method.
<Measuring method of absorption amount of 40% by weight potassium hydroxide aqueous solution>
1.00 g of the measurement sample was placed in a tea bag (length 20 cm, width 10 cm) made of a nylon net having an opening of 63 μm (JIS Z8801-1: 2006), and placed in 1,000 ml of a 40 wt% potassium hydroxide aqueous solution without stirring. After soaking for 14 hours, the tea bag is hung for 30 minutes to remove excess potassium hydroxide aqueous solution, and the weight of the tea bag (h1) is measured. The temperature of the physiological saline used and the measurement atmosphere shall be 25 ° C ± 2 ° C. The weight (h2) of the tea bag after centrifugal dehydration is measured in the same manner as above except that the measurement sample is not used, and the absorption amount of 0 wt% potassium hydroxide aqueous solution is calculated from the following formula.
40% by weight potassium hydroxide aqueous solution absorption amount (g / g) = (h1)-(h2)

In the present invention, the viscosity of a mixed solution prepared by adding 2% by weight of a gelling agent (G) to a 40% by weight potassium hydroxide aqueous solution at 25 ° C. is 10 to 60 Pa · s, preferably 25 to 50, and more preferably 30. ~ 40. If the viscosity of the mixed solution is outside the range of 10 to 60 Pa · s, excessive separation of the alkaline electrolytic solution cannot be prevented, the long-term discharge characteristics of the battery are inferior, and impact resistance and productivity (filling) are achieved. Sex) gets worse.

The viscosity of the mixed solution in which 2% by weight of the gelling agent (G) is added to the 40% by weight potassium hydroxide aqueous solution is measured by the following method.
A digital B-type viscometer was used as a measurement sample after stirring and mixing 98 parts by weight of a 40% by weight potassium hydroxide aqueous solution and 2 parts by weight of a gelling agent (G) until the mixture was left at 25 ° C. for 16 hours. (Made by TOKIMEC) is used for measurement at a measurement temperature of 25 ° C. in accordance with JIS7117-1: 1999. The rotor No. 4 is used and the measurement is performed at a rotation speed of 3 rpm.

The volume average particle size of the gelling agent (G) in the present invention is preferably 30 to 400 μm, more preferably 30 to 170 μm, and particularly preferably 30 to 100 μm.
When the volume average particle size is in this range, the viscosity of the alkaline electrolytic solution to which the gelling agent (G) is added is in a suitable range, and the negative electrode material is drained well, so that a battery with stable quality can be manufactured. It is possible to produce a battery having excellent discharge characteristics over time because it is possible to prevent the zinc powder from settling in the negative electrode material.

The volume average particle size of the gelling agent (G) of the present invention is measured by a laser diffraction type particle size distribution measuring device [Microtrac (manufactured by Nikkiso Co., Ltd.)] in which the gelling agent (G) is dispersed in methanol.

The liquid separation rate of the negative electrode material containing the gelling agent (G) of the present invention is preferably 10% by weight or less, more preferably 0.1 to 7% by weight, particularly preferably 0.3 to 5% by weight, most preferably. It is preferably 0.5 to 2.5% by weight. Within this range, the long-term discharge characteristics of the battery are further excellent.

The above liquid separation rate is measured by the following method.
<Measurement method of liquid separation rate>
100 parts by weight of a 40 wt% potassium hydroxide aqueous solution, 2 parts by weight of a gelling agent (G), and 200 parts by weight of zinc powder having a volume average particle diameter of 200 μm are stirred and mixed until uniform to prepare a negative electrode material for an alkaline battery. Weigh 75.0 g of this negative electrode material into the bottom of a tea bag made of a nylon screen with an opening of 32 μm (400 mesh) prepared in accordance with JIS K7223-1996, and let stand at 25 ° C for 168 hours (1 week). .. Then, the tea bag is suspended by a clip and allowed to stand to drain water for 30 minutes, and then the weight (W1) (g) of the tea bag after draining is measured. Further, the same operation is performed only with the tea bag without inserting the negative electrode material, and the weight (W2) (g) of the tea bag is measured. The liquid separation rate is calculated by the following formula.
Liquid separation rate (% by weight) = [{75.0}-{W1} + {W2}] / {75.0} x 100

The alkaline battery to which the gelling agent (G) of the present invention can be applied is not particularly limited, and general alkaline batteries such as LR-20 (AA alkaline battery) and LR-6 (AA alkaline battery) can be applied. Of course, it can be applied to various other alkaline batteries. Alkaline batteries generally have a structure in which a positive electrode agent, a current collector rod, and a gel negative electrode are enclosed in an outer can, and the positive electrode agent and the gel negative electrode are separated by a separator or the like.

As a method for filling an alkaline battery with the gelling agent (G) of the present invention,
(1) The gelling agent (G) of the present invention, an alkaline electrolytic solution (for example, a high-concentration potassium hydroxide aqueous solution, if necessary containing zinc oxide, etc.), zinc powder (and / or zinc alloy powder) and, if necessary, others. A method of premixing the additives of the above to prepare a mixture of negative electrode substances and filling the negative electrode container of the battery into a gel-like negative electrode.
(2) The gelling agent (G) of the present invention, zinc powder (and / or zinc alloy powder) and, if necessary, other additives are filled in the negative electrode container of the battery, and then the alkaline electrolytic solution is filled in the container. An example of a method for producing a gel-like negative electrode can be exemplified.
Of the above, the method (1) above, in which the zinc powder can be uniformly dispersed in the negative electrode container of the battery, is preferable.
The amount of the gelling agent (G) added varies depending on the structure of the negative electrode container, the particle size of the zinc powder, and the concentration of the alkaline electrolytic solution, but is 0.5 to 10% by weight based on the weight of the alkaline electrolytic solution. It is preferable, and more preferably 1.0 to 5.0% by weight. When the addition amount is 0.5 to 10% by weight, the viscosity of the alkaline electrolytic solution containing the gelling agent becomes appropriate, the zinc powder can be prevented from settling, and the handling is easy.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, ultrapure water indicates water having an electric conductivity of 0.06 μS / cm or less, and ion-exchanged water indicates water having an electric conductivity of 1.0 μS / cm or less.

<Example 1>
In a 3 liter adiabatic polymerization tank, 380 g of acrylic acid, 0.49 g of pentaerythritol triallyl ether (0.13% by weight of acrylic acid), 1.33 g of trimethylolpropane triacrylate (0.35% by weight of acrylic acid) and After adding 1600 g of ion-exchanged water and stirring and mixing to prepare an acrylic acid aqueous solution, the acrylic acid aqueous solution was cooled to 3 ° C. After cooling, nitrogen was aerated in the acrylic acid aqueous solution at a flow rate of 5 L / min to adjust the dissolved oxygen concentration in the acrylic acid aqueous solution to 0.10 ppm or less. The dissolved oxygen concentration was measured using an oxygen concentration meter (ORBISPHERE 510, manufactured by HACH ULTRA) based on the diaphragm electrode method. After confirming that the aqueous solution of acrylic acid is at 3 ° C, 2,2'-azobis (2-amidinopropane) hydrochloride (Japanese) having a concentration of 10% by weight was used as a polymerization initiator in an adiabatic polymerization tank while continuing nitrogen aeration. Kojunyaku Kogyo Co., Ltd., trade name: V-50) aqueous solution 11.40 g, 2-iodo-2-methylpropionitrile (manufactured by TCI) 0.055 g, concentration 1.0% by weight hydrogen peroxide solution 1. 14 g, 1.14 g of an L-ascorbic acid aqueous solution having a concentration of 1.0% by weight, and 0.57 g of an aqueous solution of iron (III) sulfate having a concentration of 0.1% by weight were added. After the nitrogen aeration was continued for 25 minutes after the addition of the polymerization initiator, the nitrogen aeration was stopped, and the mixture was allowed to stand for 16 hours to carry out the polymerization reaction. After standing for 16 hours, the hydrogel obtained by the polymerization reaction was taken out from the polymerization reaction tank.
The removed hydrogel was subdivided into a noodle shape with a thickness of 3 to 10 mm using a small meat chopper (manufactured by Royal), and a 49 wt% sodium hydroxide (special grade reagent) aqueous solution was added to the subdivided hydrogel. After adding 132 g, the mixture was uniformly kneaded into a water-containing gel using the small meat chopper to neutralize the mixture.
The neutralized hydrogel was laminated on a SUS screen with an opening of 850 μm to a thickness of 5 cm, and hot air at 150 ° C was blown for 1 hour using a small air-permeable dryer (manufactured by Inoue Metal Co., Ltd.). The water in the hydrogel was evaporated to obtain a dry gel.
After pulverizing the dried gel with a cooking mixer, a sieve having a particle size of 150 μm or less was collected using a sieve having an opening of 150 μm (100 mesh) to obtain the gelling agent (G-1) of the present invention.

<Example 2>
The gelling agent (G-2) of the present invention was obtained in the same manner as in Example 1 except that particles having a particle size of 45 μm or less were collected using a sieve having a mesh size of 45 μm (330 mesh).

<Example 3>
The gelling agent (G-3) of the present invention was obtained in the same manner as in Example 1 except that particles having a particle size of 250 μm or less were collected using a sieve having a mesh size of 250 μm (60 mesh).

<Example 4>
The gelling agent (G-4) of the present invention was obtained in the same manner as in Example 1 except that particles having a particle size of 600 μm or less were collected using a sieve having a mesh size of 600 μm (26 mesh).

<Example 5>
The gelling agent (G-5) of the present invention was obtained in the same manner as in Example 1 except that the charged amount of trimethylolpropane triacrylate was replaced with 0.76 g (0.20% by weight of acrylic acid).

<Example 6>
The gelling agent (G-6) of the present invention was obtained in the same manner as in Example 1 except that the amount of trimethylolpropane triacrylate charged was changed to 2.09 g (0.55% by weight based on acrylic acid). ..

<Example 7>
The gelling agent (G-7) of the present invention was obtained in the same manner as in Example 1 except that the amount of pentaerythritol triallyl ether charged was replaced with 0.38 g (0.10% by weight based on acrylic acid).

<Example 8>
The gelling agent (G-8) of the present invention was obtained in the same manner as in Example 1 except that the charge amount of pentaerythritol triallyl ether was replaced with 0.76 g (0.20% by weight based on acrylic acid).

<Example 9>
The gelling agent (G-9) of the present invention was obtained in the same manner as in Example 1 except that the amount of 2-iodo-2-methylpropionitrile charged was replaced with 0.028 g.

<Example 10>
The gelling agent (G-10) of the present invention was obtained in the same manner as in Example 1 except that the amount of 2-iodo-2-methylpropionitrile charged was replaced with 0.083 g.

<Comparative Example 1>
Acrylic acid 460.0 g, pentaerythritol triallyl ether 1.15 g (against acrylic acid 0.25% by weight), trimethylolpropane triacrylate 0.92 g (against acrylic acid 0.20% by weight) in a 3 liter adiabatic polymerization tank. ) And 1600 g of ion-exchanged water were added and mixed by stirring to prepare an acrylic acid aqueous solution, and then the acrylic acid aqueous solution was cooled to 3 ° C. After cooling, nitrogen was aerated in the acrylic acid aqueous solution at a flow rate of 5 L / min to adjust the dissolved oxygen concentration in the acrylic acid aqueous solution to 0.10 ppm or less. After confirming that the aqueous solution of acrylic acid is at 3 ° C, 2,2'-azobis (2-amidinopropane) hydrochloride (Japanese) having a concentration of 10% by weight was used as a polymerization initiator in an adiabatic polymerization tank while continuing nitrogen aeration. Kojunyaku Kogyo Co., Ltd., trade name: V-50) aqueous solution 13.8 g, concentration 1.0% by weight hydrogen peroxide solution 1.38 g, concentration 1.0% by weight L-ascorbic acid aqueous solution 1.38 g, 0.68 g of an aqueous solution of iron (III) sulfate having a concentration of 0.1% by weight was added. After the nitrogen aeration was continued for 25 minutes after the addition of the polymerization initiator, the nitrogen aeration was stopped, and the mixture was allowed to stand for 16 hours to carry out the polymerization reaction. After standing for 16 hours, the hydrogel obtained by the polymerization reaction was taken out from the polymerization reaction tank.
The removed hydrogel was subdivided into a noodle shape with a thickness of 3 to 10 mm using a small meat chopper (manufactured by Royal), and a 49 wt% sodium hydroxide (special grade reagent) aqueous solution was added to the subdivided hydrogel. After adding 169 g, the mixture was uniformly kneaded into a water-containing gel using the small meat chopper to neutralize the mixture.
The neutralized hydrogel was laminated on a SUS screen with an opening of 850 μm to a thickness of 5 cm, and hot air at 150 ° C was blown for 1 hour using a small air-permeable dryer (manufactured by Inoue Metal Co., Ltd.). The water in the hydrogel was evaporated to obtain a dry gel.
After pulverizing the dried gel with a cooking mixer, a sieve having a particle size of 45 μm or less was collected using a sieve having an opening of 45 μm (330 mesh) to obtain a gelling agent (H-1).

<Comparative Example 2>
A gelling agent (H-2) was obtained in the same manner as in Comparative Example 1 except that particles having a particle size of 150 μm or less were collected using a sieve having a mesh size of 150 μm (100 mesh).

<Comparative Example 3>
A gelling agent (H-3) was obtained in the same manner as in Comparative Example 1 except that particles having a particle size of 250 μm or less were collected using a sieve having a mesh size of 250 μm (60 mesh).

<Comparative Example 4>
A gelling agent (H-4) was obtained in the same manner as in Comparative Example 1 except that particles having a particle size of 600 μm or less were collected using a sieve having a mesh size of 600 μm (26 mesh).

<Comparative Example 5>
A commercially available Carbopol 974PNF (manufactured by Rubysol Advanced Materials. Inc) was used as a gelling agent (H-5) for comparison.

Regarding the gelling agents (G-1) to (G-10) produced in Examples 1 to 10 and the comparative gelling agents (H-1) to (H-5) produced in Comparative Examples 1 to 4, the gelling agents (H-1) to (H-5) were prepared. Volume average particle size, amount of soluble component in physiological saline, Mw / Mn of component having a molecular weight of 100,000 or less, 40% by weight potassium hydroxide mixed with 2% by weight of gelling agent The results of measuring the viscosity and the absorption amount of the 40% by weight potassium hydroxide aqueous solution by the above-mentioned method are shown in Table 1 together with the ratio of the cross-linking agent used as the gelling agent and the degree of neutralization.

Further, using the gelling agents (G-1) to (G-10) of the present invention and the comparative gelling agents (H-1) to (H-5), the sedimentation property, injection time and injection of zinc powder are used. Table 2 shows the results of measuring the amount variation, battery duration and impact resistance by the following methods.

(1) Precipitation of zinc powder Zinc powder (UNION MINIERES) with a volume average particle diameter of 200 μm and 150 g of 33 wt% potassium hydroxide aqueous solution in a biaxial kneader (manufactured by Irie Trading Co., Ltd., product name: PNV-1) with a capacity of 1 liter. A. Co., Ltd.) 300 g and 3.0 g of a gelling agent were added and mixed at a rotation speed of 50 rpm for 60 minutes to prepare a negative electrode material. 50 g of the prepared negative electrode material was placed in a sample bottle (diameter 34 mm, height 77 mm, made of polypropylene) having a sealable capacity of 50 ml, and the bubbles entered during mixing were defoamed under reduced pressure.
After sealing the sample bottle and leaving it in a constant temperature bath at 40 ° C for 30 days, use the device attached to the powder tester (manufactured by Hosokawa Micron Co., Ltd.) to squeeze the sample bottle 300 times from a height of 3 cm at a rate of 30 times / min. Tapping was promoted to settle the zinc powder. After finishing tapping, the most sedimented distance (mm) of the zinc powder is measured from the initial position of the zinc powder (the position of the upper end of the negative electrode material in the sample bottle), and this is the sedimentation property (mm) of the zinc powder. And said.

(2) Variation in injection time and injection amount In a biaxial kneader with a capacity of 1 liter, 150 g of 33 wt% potassium hydroxide aqueous solution, 300 g of zinc powder (manufactured by UNION MINIERES.A.) having a volume average particle diameter of 200 μm, and a gelling agent. 3.0 g was added and mixed at a rotation speed of 50 rpm for 60 minutes to prepare a negative electrode material. The prepared negative electrode material was transferred to a beaker, and the bubbles that entered during mixing were defoamed under reduced pressure. The defoamed negative electrode material was sucked into a 10 ml syringe having an inner diameter of 2 mm and a scale of 0.1 ml unit.
From the height of the mouth of a 5 ml sample bottle (inner diameter 18 mm, height 40 mm), push in the syringe by 5.0 ml to inject the negative electrode material into the sample bottle, and from the time when the pushing of the syringe is completed, the negative electrode from the syringe inlet. The time (seconds) until the material was completely separated was measured with a stop watch. The same operation was repeated 20 times in total, and the average value was taken as the injection time (seconds).
The weight of the negative electrode gel injected into the sample bottle (20 times each) was measured, and the standard deviation (σ) of the injection amount was calculated to determine the variation in the injection amount.

(3) Battery duration In a biaxial kneader with a capacity of 1 liter, 150 g of a 33 wt% potassium hydroxide aqueous solution, 300 g of zinc powder (manufactured by UNION MINIERES.A.) having a volume average particle diameter of 200 μm, and a gelling agent 3 .0 g was added and mixed at 50 rpm for 60 minutes to prepare a negative electrode material, and after defoaming under reduced pressure, 15 g of this negative electrode material was injected into the negative electrode container of the LR-6 type model battery. A model battery was manufactured.
As the constituent materials of each part other than the negative electrode material of the model battery, polyethylene is used as the material of the shrink tube, and 50 parts by weight of electrolytic manganese dioxide, 5 parts by weight of acetylene black and 40% by weight of potassium hydroxide are used as the material of the positive electrode material. A compound consisting of 1 part by weight of an aqueous solution, a nickel-plated steel plate as the material of the outer can, a polyolefin as the material of the separator, a tin-plated brass rod as the material of the current collector, and a polyolefin resin and a negative electrode as the material of the gasket. A nickel-plated steel plate was used as the material of the terminal plate.
An external resistor of 2Ω was connected to the produced model battery at room temperature (20 to 25 ° C.), and the battery was continuously discharged, and the time until the voltage dropped to 0.9V was defined as the battery duration (hour).
After producing the model battery, the same operation was performed on the model battery that had been allowed to stand in a constant temperature bath at 80 ° C. for 15 days, and the battery duration was measured.

(4) Impact resistance of the battery To the model battery manufactured in the same manner as above, connect an external resistance of 2Ω at room temperature (20 to 25 ° C) and continuously discharge the model battery from a height of 1 m on wood. The battery was dropped 10 times in a row, the voltage before the first drop and the voltage immediately after the 10th drop were measured, and the impact resistance (%) was calculated by the following formula.
Impact resistance (%) = {voltage immediately after the 10th drop (V) / voltage before the first drop (V)} x 100
After producing the model battery, the same operation was performed on the model battery that had been allowed to stand in a constant temperature bath at 80 ° C. for 15 days, and the impact resistance was obtained.

The gelling agent (G) of the present invention can be used not only as a gelling agent for a cylindrical alkaline battery but also as a gelling agent for primary and secondary alkaline batteries such as alkaline button batteries, silver oxide batteries, nickel cadmium storage batteries and nickel hydrogen storage batteries. It is useful. Further, the alkaline battery using the gelling agent of the present invention is useful as an alkaline battery having improved production efficiency because it has excellent impact resistance, excellent discharge characteristics, and excellent viscosity stability of the negative electrode material.

Claims (5)

It contains a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) that becomes (a1) by hydrolysis and a cross-linked polymer (A) containing a cross-linking agent (b) as an essential constituent monomer, and contains the following (1). )-(3), a gelling agent (G) for an alkaline battery.
(1) The amount of the soluble component of the crosslinked polymer (A) in physiological saline is 5 to 20% by weight based on the weight of (A).
(2) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the components having a molecular weight of 100,000 or less among the soluble components of the crosslinked polymer (A) in physiological saline is It is 4.0 to 6.0.
(3) The viscosity of a mixed solution prepared by adding 2% by weight of the gelling agent (G) to a 40% by weight potassium hydroxide aqueous solution at 25 ° C. is 10 to 60 Pa · s. The gelling agent for an alkaline battery according to claim 1, wherein the absorption amount of the 40% by weight potassium hydroxide aqueous solution is 40 to 70 g / g. The cross-linking agent (b) is composed of a cross-linking agent (b1) that hydrolyzes with an alkali and a cross-linking agent (b2) that does not hydrolyze with an alkali, and the respective amounts are the sum of the water-soluble vinyl monomer (a1) and the vinyl monomer (a2). The alkaline battery according to claim 1 or 2, wherein the weight is 0.05 to 1% by weight based on the weight, and the weight ratio [(b1) / (b2)] of (b1) to (b2) is 1.5 to 5. Gelling agent for. 100 parts by weight of 33% by weight potassium hydroxide aqueous solution, 2 parts by weight of gelling agent (G) and 200 parts by weight of zinc powder were stirred and mixed until uniform, and allowed to stand at 25 ° C. for 24 hours. The gelling agent for an alkaline battery according to any one of claims 1 to 3, which is 10% by weight or less. An alkaline battery containing the gelling agent for an alkaline battery and zinc powder according to any one of claims 1 to 4.