JP2007131731A - Normal temperature-crosslinkable water-based synthetic resin composition and normal temperature-crosslinkable water-based coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based synthetic resin composition hardly causing problems on the environmental hygiene, suitable for a coating material, ink, an adhesive, a coating agent or the like, and capable of being crosslinked at normal temperature. <P>SOLUTION: The normal temperature-crosslinkable water-based synthetic resin-dispersed composition is obtained by adding a quaternized chitosan represented by general formula (1) (wherein, R is a lower alkyl group; X<SP>-</SP>is a halogen ion; and m and n are each a positive integer) as a crosslinking agent to an aqueous dispersion of a polymeric resin of a copolymer of a carbonyl group-containing unsaturated monomer and at least one kind of a monomer selected from unsaturated carboxylic acid compounds, and having (-20)-(+50)°C glass transition temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aqueous synthetic resin composition that can be crosslinked at room temperature. In particular, the present invention relates to a synthetic resin aqueous emulsion composition suitable for use as a paint, ink, adhesive, coating agent, or the like, having no environmental health problems.

  Conventionally, in the fields of paints, inks, adhesives, etc., from the viewpoints of resource saving, environmental sanitation, pollution-free, safety, etc., conversion from organic solvent type to water-based type has been promoted. Typical examples of water-based paints include those using acrylic copolymer emulsion as a vehicle component, but since the fusion of emulsion particles is essential during film formation, the glass transition temperature of the resin used is lowered. Therefore, there is a problem in contamination resistance and water resistance. To solve this problem, there is a method of crosslinking the emulsion with a water-soluble or water-dispersible polyisocyanate. Moreover, as what solved the above problems of an acrylic copolymer emulsion, the thing using the emulsion composition formed by mix | blending the copolymer emulsion which has a carbonyl group, and a dihydrazide compound is proposed ( Patent Literatures 1 to 3). However, environmental hygiene restrictions may occur due to the toxicity of the hydrazide compounds used.

Further, there has been proposed a room-temperature-crosslinking type synthetic resin emulsion composition prepared by using a basic amino acid as a crosslinking agent without using a hydrazine derivative and blended with a synthetic resin aqueous emulsion containing a carbonyl group (for example, (See Patent Documents 4 and 5).
US Pat. No. 3,345,336 Japanese Patent Publication No. 58-20991 Japanese Patent Laid-Open No. 4-249487 JP-A-9-165523 JP 2004-123850 A

  It is an object of the present invention to provide a synthetic resin aqueous emulsion composition having a low environmental load and suitable as a paint, ink, adhesive, coating agent, etc. having weather resistance that is free from environmental health problems. .

  The inventors of the present invention have developed a water-based synthetic resin composition that can be used for paints having the above-described properties, and have developed a heavy polymer containing a carbonyl group and a carboxyl group, which has been used together with a basic amino acid crosslinking agent. As a result of repeated studies on the use of quaternized chitosan as a crosslinking agent for coalescence, the present invention has been completed.

  Chitosan is a deacetylated form of chitin, which is a complex of calcium and protein, and is the only polysaccharide having an amino group. Chitin is one of the natural polymers widely distributed on the earth as a component of shells of crustaceans such as sharks and shrimps, and shells of insects. Chitosan is a white or deep red solid, a kind of dietary fiber that is insoluble in water and organic solvents, and has been used as a flocculant for wastewater and activated sludge from food factories. Since then, the range of use has increased for cosmetics, artificial skin, fibers, food materials, etc. Recently, it has attracted attention as a functional food for adult diseases (lifestyle-related diseases), and has already become a food additive. As a result, it is also being developed for general food ingredients and health foods.

As described above, chitosan is naturally produced and has a highly reactive functional group such as an amino group or a hydroxyl group, so it has excellent malodorous component adsorption, formaldehyde adsorption, antibacterial activity, biodegradability, etc. Have nature. However, water-based paints that take advantage of these excellent functions have hardly been studied. This is because chitosan itself is insoluble in water and reacts with anionic emulsifiers and anionic additives often used in water-based paints in order to show polycationic properties in aqueous acid solutions. This is considered to be caused by aggregation. Therefore, the present inventors examined the case where a part of the amino group in the chitosan was quaternized alkylated quaternized chitosan. As a result, the quaternized chitosan showed water solubility, and the carbonyl group and the carboxyl group Has been found to be capable of forming a non-polluting coating film that acts as a crosslinking agent for a polymer containing benzene, is excellent in room temperature curability, and has a low environmental load. .
The present invention includes the following inventions.

〔式中、Ｒは低級アルキル基、Ｘ⁻はハロゲンイオンを表し、ｍ及びｎは正の整数を表す。〕 (1) A copolymer of a carbonyl group-containing unsaturated monomer and a carboxyl group-containing unsaturated monomer, and having an aqueous dispersion of a polymer resin having a glass transition temperature of -20 ° C to + 50 ° C A room temperature crosslinking aqueous synthetic resin dispersion composition obtained by adding quaternized chitosan represented by the following general formula as a crosslinking agent.

[Wherein, R represents a lower alkyl group, X ⁻ represents a halogen ion, and m and n represent a positive integer. ]

(2) The aqueous dispersion of the polymer resin is prepared by emulsion polymerization of a carbonyl group-containing unsaturated monomer and a carboxyl group-containing unsaturated monomer (1) A room-temperature-crosslinking aqueous synthetic resin dispersion composition described in the item.

(3) In addition to the carbonyl group-containing unsaturated monomer and the carboxyl group-containing unsaturated monomer, the aqueous dispersion of the polymer resin may contain other monomers that are copolymerizable with both monomer components. The room-temperature-crosslinking aqueous synthetic resin dispersion composition according to (1) or (2), wherein the composition is prepared by emulsion polymerization with a body.

(4) The quaternized chitosan is produced by reacting an alkyl halide with chitosan as a quaternizing agent in a solvent, any one of (1) to (3) Item 1. A room-temperature-crosslinking aqueous synthetic resin dispersion composition according to item 1.

(5) The room temperature cross-linking aqueous synthetic resin dispersion composition according to item (4), wherein the alkyl halide is an alkyl iodide.

(6) The quaternized chitosan is prepared by reacting an alkyl iodide with chitosan to prepare an iodine type quaternized chitosan having an iodine ion as a counter ion. Then, sodium chloride or sodium bromide is added to the resulting reaction solution. The chlorine ion or bromine ion added to replace the chlorine ion or bromine ion to obtain a chlorine-type quaternized chitosan or bromine-type quaternized chitosan as a counter ion. The room temperature cross-linking aqueous synthesis according to any one of (1) to (5), characterized in that it is a chlorinated quaternized chitosan or a bromine quaternized chitosan having a bromine ion as a counter ion Resin dispersion composition.

(7) A room-temperature-crosslinking water-based paint containing the room-temperature-crosslinking aqueous synthetic resin dispersion composition described in any one of (1) to (6).

  The room temperature cross-linking aqueous synthetic resin dispersion composition of the present invention forms a stable emulsion, so that a product excellent in storage stability can be prepared and a coating film excellent in stain resistance can be formed. In addition, since it is not toxic and has no environmental hygiene problems, it is suitable for applications such as coating compositions.

  The synthetic resin in the room temperature crosslinking aqueous synthetic resin dispersion composition of the present invention is a co-polymer of a carbonyl group-containing unsaturated monomer selected from an unsaturated aldehyde compound and an unsaturated ketone compound and a carboxyl group-containing unsaturated monomer. A polymer resin having a glass transition temperature of −20 ° C. to + 50 ° C.

  One monomer component forming the synthetic resin in the room temperature crosslinking aqueous synthetic resin dispersion composition of the present invention is a carbonyl group-containing unsaturated monomer component. The carbonyl group-containing unsaturated monomer means a compound having an aldo group or keto group in the molecule and having a polymerizable double bond.

  Examples of carbonyl group-containing unsaturated monomers include acrolein, metaacrolein, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, vinyl isobutyl ketone, acetoacetoxypropyl clonate, acetoacetoxymethyl acrylate, acetoacetoxymethyl methacrylate, Acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, acetoacetoxypropyl acrylate, acetoacetoxypropyl methacrylate, formylstyrene, diacetone acrylate, diacetone methacrylate, acetonyl acrylate, diacetone acrylamide, diacetone methacrylamide, 2-hydroxypropyl acrylate Acetyl acetate, butanediol-1,4-acrylate Cetyl acetate, acryloxyalkyl propanal, methacrylic oxyalkylation propanal or the like. Among these, acetoacetyl group-containing unsaturated compounds such as acetoacetoxypropyl clonate, acetoacetoxymethyl acrylate, acetoacetoxymethyl methacrylate, acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, acetoacetoxypropyl acrylate, acetoacetoxypropyl methacrylate, etc. Is preferred.

  The other monomer component forming the synthetic resin in the room temperature crosslinking aqueous synthetic resin dispersion composition of the present invention is a monomer component composed of a carboxyl group-containing polymerizable unsaturated compound. Examples of such a monomer component include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, crotonic acid, and itaconic acid, and β-carboxyethyl acrylate. Among these carboxyl group-containing polymerizable unsaturated compounds, acrylic acid and methacrylic acid are preferred because they are easily available and easily copolymerized with other polymerizable monomers.

  The synthetic resin in the room temperature cross-linkable aqueous synthetic resin dispersion composition of the present invention includes, in addition to the monomer component consisting of the carbonyl group-containing unsaturated monomer component and the carboxyl group-containing polymerizable unsaturated compound, Other copolymerizable unsaturated compounds that can be easily copolymerized with the monomer component can be used as the monomer component.

  Examples of such other copolymerizable monomer compounds include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, acrylic acid or n-butyl methacrylate. i-butyl, t-butyl ester, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, nonyl acrylate, nonyl methacrylate, decyl acrylate, decyl methacrylate, cyclohexyl acrylate, methacrylic acid Cyclohexyl, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, isonorbornyl acrylate, isonorbornyl methacrylate, 1,2,2,6,6-pentamethylpiperidyl acrylate, 1,2, methacrylate 2,6,6-pen Methylpiperidyl, 2- (2'-hydroxy-5'-methacrylic acid 2,2,6,6-tetramethylpiperidinyl and other acrylic acid or methacrylic acid esters, vinyl aromatic compounds such as styrene and vinyltoluene N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, acrylonitrile, methacrylonitrile, etc. These may be used alone or in combination of two or more according to the desired performance. .

  Moreover, as another monomer compound, the monomer which has a hydrophilic group can also be used, and it is preferable to use these within the range which does not have a bad influence on the water permeability of a coating film. Monomers having a hydrophilic group include 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, sodium styrene sulfonate, sulfoethyl methacrylate and its sodium and ammonium salts, acrylamide, methacrylamide, dimethylamino. Propylmethacrylamide, dimethylaminopropylacrylamide, dimethylaminoethylmethacrylamide, dimethylaminoethylacrylamide, glycidyl acrylate, adducts of glycidyl methacrylate and amines, acrylates and methacrylates having polyoxyethylene chains, 2-hydroxyethyl acrylate, Acrylic such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate And hydroxyalkyl esters of methacrylic acid.

  The aqueous synthetic resin dispersion in the room temperature crosslinking aqueous synthetic resin dispersion composition of the present invention is composed of at least one monomer component selected from the unsaturated aldehyde compound and unsaturated ketone compound and a carboxyl group-containing polymerizable unsaturated compound. A copolymer emulsion produced by emulsion polymerization in the presence of water with a monomer component consisting of the above and, if necessary, the other copolymerizable unsaturated monomer component.

Quaternized chitosan is used as a crosslinking agent in the room temperature crosslinking aqueous synthetic resin dispersion composition of the present invention. Quaternized chitosan can be obtained by reacting alkyl halide with chitosan as a quaternizing agent.
Chitosan is a deacetylated product of chitin which is a compound having a (1-4) -2-acetamido-2-deoxy-β-D-glucan structure, that is, (1-4) -2-amino-2-deoxy- It is a compound having a β-D-glucan structure. In the present invention, the quaternized chitosan is a reaction in which a part of the deacetylated amino group in the chitosan molecule or a part of the hydroxyl group in the molecule is acyl, etherification reaction, esterification reaction, etc. A compound that has been chemically modified by the reaction of

In general, naturally occurring chitin is an amino group in which part of the acetamide group is not acylated (the degree of deacetylation of the N-acetyl group is 20% or less). As the raw material chitosan of the quaternized chitosan or a derivative thereof, a chitosan hydrolyzed to have a N-acetyl group deacetylation degree of 60% or more is preferable. For example, chitosan having an N-acetyl group deacetylation degree of 80% contains a lot of highly reactive amino groups, so that quaternary alkylation of amino groups is likely to occur. In the quaternized chitosan, a preferable alkyl group is an alkyl group having 1 to 12 carbon atoms such as methyl, ethyl, propyl, or butyl, and more preferably a lower alkyl group having 1 to 3 carbon atoms.
As the alkyl halide for quaternizing chitosan, alkyl iodide is preferred because of its good reactivity with chitosan. Among the alkyl halides, chlorinated alkyls and brominated alkyls are not practical because the reaction with chitosan is very slow.

When an alkyl iodide having good reactivity with chitosan is reacted with chitosan, iodine-type quaternized chitosan is prepared by reacting chitosan and alkyl iodide in a solvent such as an aqueous alcohol solution and using an iodine ion as a counter ion. In the reaction solution, unreacted alkyl iodides and solvent are present in addition to iodine-type quaternized chitosan.
Therefore, sodium chloride is added to this reaction solution and reacted with iodine-type quaternized chitosan to replace iodine ion and chlorine ion to obtain chlorine-type quaternized chitosan having chlorine ion as a counter ion. be able to. Alternatively, bromine-type quaternized chitosan having a bromine ion as a counter ion can be obtained by reacting with iodine-type quaternized chitosan using sodium bromide instead of sodium chloride.

In the reaction solution obtained as described above, unreacted alkyl iodide, unreacted sodium chloride or sodium bromide, and a solvent are present in addition to chlorine-type or bromine-type quaternized chitosan. Therefore, it is necessary to isolate and purify chlorinated or brominated quaternized chitosan as a solid from the reaction solution.
Therefore, first, this reaction solution is poured into a large amount of non-aqueous solvent that does not dissolve chlorine-type or bromine-type quaternized chitosan such as acetone, to precipitate and precipitate chlorine-type or bromine-type quaternized chitosan, Chlorine-type or bromine-type quaternized chitosan obtained by precipitation is washed with a large amount of non-aqueous solvent and then vacuum-dried. At this stage, the purity of chlorinated or brominated quaternized chitosan is low, so it is dissolved in water, poured again into a large amount of non-aqueous solvent and reprecipitated, and this precipitate is washed with a non-aqueous solvent. By repeating this vacuum drying several times, a purified chlorinated or brominated quaternized chitosan can be obtained.

  The mixing ratio of the polymer aqueous dispersion and the quaternized chitosan in the room temperature crosslinkable aqueous synthetic resin dispersion composition of the present invention is such that the amino group in the quaternized chitosan is 1 mol of the carbonyl group in the polymer aqueous dispersion. The blending ratio is 0.01 to 5 mol.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely according to an Example, this invention is not limited at all by these Examples. In each example, “parts” and “%” indicate “parts by mass” and “mass%”.

(Synthesis of quaternized chitosan)
Into a four-necked flask, 18.0 g of Chitosan (manufactured by Kyowa Technos Co., Ltd., trade name: Flownack C-60M, degree of deacetylation 88%), 1320 ml of distilled water and 960 ml of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the whole was 50 The mixture was stirred at 0 ° C., and chitosan was dispersed in the mixed solvent. Subsequently, 36.0 ml of iodomethane (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped into this dispersion and reacted with chitosan over 6 hours. The iodine salt of quaternary ammonium was thus converted to the hydrochloride salt. The reaction solution was poured into 3 times the amount of acetone (manufactured by Wako Pure Chemical Industries, Ltd.) to form a flocculent precipitate, which was taken out, suction filtered, washed with acetone again, and dried under reduced pressure. This dried product was again dissolved in distilled water to obtain a 2% by mass solution of quaternary ammonium hydrochloride.
This solution was poured into 6 times the amount of acetone (manufactured by Wako Pure Chemical Industries, Ltd.) to form a flocculent precipitate, which was taken out and dried under reduced pressure.
In this way, quaternized chitosan was synthesized. The obtained quaternized chitosan was identified by 1H-NMR spectroscopy. The degree of quaternization was about 20%.

[Synthesis of acrylic emulsion (1)]
In a separable flask equipped with a cooling tube, a thermometer, and a dropping funnel, ion-exchanged water and nonionic reactive emulsifier (Adekaria soap ER-20, ER-30, manufactured by Asahi Denka Kogyo Co., Ltd.) are added, and the temperature is 60 Held at 0C. An emulsified mixture obtained by emulsifying a monomer in which a reactive emulsifier is dissolved and ion-exchanged water at 10,000 rpm in a homomixer is put into a dropping funnel, and a part of the mixture is put into a reaction vessel, and a polymerization initiator [2,2′-azobis (2-Amidinopropane) dihydrochloride] 0.45 part dissolved in a small amount of water was added and the reaction was started. After the reaction solution changed from white to bluish white, the mixture was added dropwise from a dropping funnel over 2 hours. After the dropwise addition, a solution prepared by dissolving 0.15 part of the remaining 2,2′-azobis (2-amidinopropane) dihydrochloride with a small amount of water was added, the temperature was raised to 70 ° C., and aging was performed for 2 hours. . After 2 hours, the mixture was cooled to obtain an acrylic emulsion (1). The composition of the raw materials used is shown in Table 1.

[Synthesis of acrylic emulsions (2) and (3)]
12.5 parts of diacetone acrylamide [manufactured by Kyowa Hakko Kogyo Co., Ltd.] is dissolved in 136 parts of methyl methacrylate, 94 parts of 2-ethylhexyl acrylate, 2.5 parts of acrylic acid, and 5 parts of 2-hydroxylethyl acrylate, and ion-exchanged water. 117.25 parts and an anionic reactive emulsifier [ADEKA rear soap SR-10: manufactured by Asahi Denka Kogyo Co., Ltd.] In addition to dissolving 16.5 parts, an emulsified mixture was obtained by mixing at 10,000 rpm with a homogenizer. It was. The temperature at which 90% of ion-exchanged water maintained at a temperature of 80 ° C. and 5% of this emulsified mixture and 0.25 part of an anionic reactive emulsifier [ADEKA rear soap SR-10: manufactured by Asahi Denka Kogyo Co., Ltd.] The reaction was started by adding the total amount of 1 part of ammonium persulfate dissolved in 25 parts of ion-exchanged water as a polymerization initiator in a separable flask equipped with a meter, a condenser, a dropping funnel and a stirrer. After 5 minutes, the remaining emulsified mixture was added dropwise over 3 hours. After completion of the dropping, aging was performed at 80 ° C. for 2 hours. After the completion of aging, the mixture was cooled to 60 ° C. and adjusted to pH 8-9 with aqueous ammonia. Table 2 shows the composition of the raw materials used.

Example 1
52 parts acrylic emulsion 1, 20 parts calcium carbonate [manufactured by Maruo Calcium Co., Ltd., heavy calcium carbonate], 0.1 part cellulose thickener (RHEOX, Benaqua 1000), non-silicone aqueous defoamer (San Nopco, SN deformer 777) 0.4 parts, rheology control agent (RHEOX, Rheorate 216) 1.0 parts, titanium dioxide (DuPont, R-706) 25 parts, nonionic wetting agent [Asahi 1.0 part of Adecatol TN-100] manufactured by Denka Co., Ltd. and 0.5 part of an anionic dispersant [manufactured by Kao Corporation, Poise 521] were mixed and stirred well with a disper until uniform. A coating composition was prepared.
A matte paint (white enamel) was prepared by adding 0.5 part of quaternized chitosan synthesized as described above to 100 parts of this paint composition.

Example 2
A matte paint (white enamel) was prepared by adding 1.0 part of the quaternized chitosan synthesized as described above to 100 parts of the paint composition of Example 1.

Example 3
A matte paint (white enamel) was prepared by adding 2.0 parts of the quaternized chitosan synthesized as described above to 100 parts of the paint composition of Example 1.

Comparative Example 1
The coating composition of Example 1 was used as a coating as it was.

Example 4
86 parts of the pigment mill base shown in Table 3 and 200 parts of the acrylic resin emulsion (2) (100 parts in terms of solid content) were added and stirred, and further the film forming aid [2,2,4-trimethyl-1 , 3-pentanediol monoisobutyrate, trade name “CS-12”, manufactured by Chisso Corp.], and mixed by stirring. Further, 4.0 parts of quaternized chitosan synthesized as described above was added to the paint. (White enamel) was prepared.

Comparative Example 2
86 parts of the pigment mill base shown in Table 3 and 200 parts of the acrylic resin emulsion (3) (100 parts in terms of solid content) were added and stirred, and further the film forming aid [2,2,4-trimethyl-1 , 3-pentanediol monoisobutyrate, trade name “CS-12”, manufactured by Chisso Corporation] and mixed with stirring, and 4.0 parts of quaternized chitosan is added to prepare a paint (white enamel). did.

(Storage stability test)
Table 3 and Table 4 show the presence or absence of aggregates and changes in viscosity after placing the paints of Examples and Comparative Examples in plastic containers and leaving them in a dryer at 50 ° C. for 7 days according to the following criteria. It was.
◎: No aggregate and no change in viscosity ○: No aggregate and some change in viscosity ×: A large amount of aggregate is seen or gelled

(Water resistance test)
The paints of Examples and Comparative Examples were applied to a flexible plate treated with a sealer (manufactured by Tsuwa Chemical Industry Co., Ltd., Diamond Wide Sealer) using a spray, which was left at room temperature for 1 week to obtain a test piece. The test piece was immersed in water and the test piece was pulled up 24 hours later, and the coated surface was visually evaluated according to the following criteria. Tables 3 and 4 are shown.
◎: No bulge ○: Fine and partial bulge ×: Full bulge or elution of coating film

As is apparent from the results of Tables 3 and 4, the aqueous synthetic resin dispersion composition of the present invention that crosslinks at room temperature has a cured film with excellent solvent resistance and a film with excellent water resistance and heat resistance. Since it is formed, it can be used in a wide range of fields such as paints, inks, adhesives, and coating agents.

Claims (7)

A copolymer of a carbonyl group-containing unsaturated monomer and at least one monomer selected from unsaturated carboxylic acid compounds, having a glass transition temperature of −20 ° C. to + 50 ° C. A room temperature crosslinking aqueous synthetic resin dispersion composition obtained by adding a quaternized chitosan represented by the following general formula as a crosslinking agent to an aqueous dispersion.

[Wherein, R represents a lower alkyl group, X ⁻ represents a halogen ion, and m and n represent a positive integer. ]   The aqueous dispersion of the polymer resin is prepared by emulsion polymerization of a carbonyl group-containing unsaturated monomer and at least one monomer selected from unsaturated carboxylic acid compounds. The room temperature crosslinking aqueous synthetic resin dispersion composition according to claim 1.   The aqueous dispersion of the polymer resin can be copolymerized with both monomer components in addition to the carbonyl group-containing unsaturated monomer and at least one monomer selected from unsaturated carboxylic acid compounds. The room-temperature-crosslinking aqueous synthetic resin dispersion composition according to claim 1, wherein the composition is prepared by emulsion polymerization with other monomers.   4. The room temperature crosslinking according to claim 1, wherein the quaternized chitosan is produced by reacting an alkyl halide with chitosan as a quaternizing agent in a solvent. Type aqueous synthetic resin dispersion composition.   5. The room temperature crosslinking aqueous synthetic resin dispersion composition according to claim 4, wherein the alkyl halide is an alkyl iodide.   The quaternized chitosan is prepared by reacting an alkyl iodide with chitosan to prepare an iodine type quaternized chitosan having an iodine ion as a counter ion, and then adding sodium chloride or sodium bromide to the resulting reaction solution. It is prepared by substituting chlorine ions or bromine ions for iodine ions, and is a chlorinated quaternized chitosan with a chlorine ion as a counter ion or a bromine-type quaternized chitosan with a bromine ion as a counter ion The room temperature cross-linking type aqueous synthetic resin dispersion composition according to any one of claims 1 to 5. A room-temperature-crosslinking water-based paint containing the room-temperature-crosslinking water-based synthetic resin dispersion composition according to claim 1.