JP2000198975A - Antistatic agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antistatic agent excellent in ink-fixing properties by incorporating a carboxyalkylcellulose nitrate specified in the degree of substitution by nitrate groups and in the degree of substitution by carboxyalkyl ether groups per anhydrous glucose unit into the same. SOLUTION: This agent contains (A) 3-80 wt.% carboxyalkylcellulose nitrate having a degree of substitution by nitrate groups of 0.2-2.95 and a degree of substitution by carboxyalkyl ether groups of 0.05-2.8 per anhydrous glucose unit and (B) 20-97 wt.% other water-soluble polymer (e.g. a cation-modified polyvinyl alcohol such as a quaternary ammonium salt). If necessary, the agent further contains a hydroxylated crosslinker (e.g. a melamine resin), 0.1-10 wt.% (based on the sum of ingredients A and B) at least one surfactant selected from among anionic, cationic, nonionic, and amphoteric surfactants, 20 wt.% or lower water-soluble cationic polymer (e.g. polythiourea), a pH-adjusting agent, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an antistatic agent. More specifically, the present invention relates to an antistatic agent having excellent ink fixability.

[0002]

2. Description of the Related Art A resin having a low polarity, such as nitrified cotton, has a high chargeability and is easily adhered when coated and laminated on various types of supports, thereby reducing sheet transportability or causing dust to adhere due to generation of static electricity. There are drawbacks such as ease of fixation and insufficient fixation of aqueous ink.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an antistatic agent having excellent ink fixability.

[0004]

The present inventor has found that nitric esters of carboxyalkylcellulose are useful for solving the above-mentioned problems, and have completed the present invention. That is, the present invention relates to a carboxyalkyl cellulose nitrate having a degree of substitution of nitric acid ester groups of 0.2 to 2.95 and a degree of substitution of carboxyalkyl ether groups of 0.05 to 2.8 per anhydroglucose unit. It is an antistatic agent characterized by containing.

Hereinafter, the present invention will be described in detail. The carboxyalkyl cellulose nitrate used in the present invention is a carboxyalkyl cellulose having a nitrate ester substitution degree of 0.2 to 2.95 and a carboxyalkyl ether group substitution degree of 0.05 to 2.8. For example, it refers to a product prepared by reacting carboxymethylcellulose in a mixed acid of nitric acid, sulfuric acid and water, and specifically, an aqueous cellulose derivative disclosed in JP-A-5-39301 and JP-A-5-39302. Can be used.

If the degree of substitution of the nitrate group is less than 0.2,
The water resistance of the coating film is insufficient, and if it exceeds 2.95, the hydrophilicity becomes insufficient. If the degree of substitution of the carboxyalkyl ether group is less than 0.05, the hydrophilicity becomes insufficient and the antistatic property decreases. If the degree exceeds 2.8, the water resistance of the coating film becomes insufficient. In the present invention, the preferred range of the degree of substitution of the nitrate group of the nitrates of the carboxyalkyl cellulose is 0.2 or more and 2.2 or less, and the preferred range of the degree of substitution of the carboxyalkyl ether group is 0.05 or more.
1.5 or less.

In the present invention, it is preferable to use a water-soluble polymer other than the above-mentioned carboxyalkyl cellulose nitrates in order to obtain a film-forming property and a good ink fixing property. Examples of the aqueous polymer that can be used in the present invention include lime-treated gelatin, acid-treated gelatin, gelatin derivatives such as enzyme-treated gelatin, for example, phthalic acid, maleic acid, gelatin reacted with an anhydride of a dibasic acid such as fumaric acid, and the like. Various gelatin, oxidized starch, starches such as etherified starch, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, cellulose derivatives such as hydroxyethyl cellulose, polyalkylene oxide and their derivatives, polyacrylic acid,
Polymethacrylic acid or its esters, salts and their copolymers, polyhydroxyethyl methacrylate and its copolymers, polyvinylpyrrolidone, polyvinylpyridium halide, polyvinyl alcohol of various degrees of saponification, cationic modification, carboxy modification, amphoteric Polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether / maleic anhydride copolymer, styrene / maleic anhydride copolymer, and salts thereof, synthetic polymers such as polyethyleneimine, styrene / butadiene copolymer, Conjugated diene copolymer latex such as methyl methacrylate / butadiene copolymer, polyvinyl acetate, vinyl acetate / maleate copolymer, vinyl acetate / acrylate copolymer Body, vinyl acetate copolymer latex such as ethylene-vinyl acetate copolymer, an acrylic acid ester polymer, methacrylate polymer, ethylene
Acrylic ester copolymers, latexes of acrylic polymers or copolymers such as styrene / acrylic ester copolymers, vinylidene chloride-based copolymer latexes, or monomers containing functional groups such as carboxyl groups of these various polymers Aqueous adhesives such as thermosetting synthetic resins such as functional group-modified polymer latex, melamine resin, urea resin, etc., polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride / vinyl acetate copolymer, polyvinyl Synthetic resins such as butyral and alkyd resins can be mentioned. In particular, cationically modified polyvinyl alcohol is preferred from the viewpoint of the water resistance of the coating film and the ink fixing property.

The cation-modified polyvinyl alcohol which can be used in the present invention includes an amide group, an imide group, a primary amino group, a secondary amino group, a tertiary amino group, a primary ammonium base, a secondary ammonium base, and a tertiary ammonium. base,
Polyvinyl alcohol containing at least one cationic group selected from quaternary ammonium bases,
Grade ammonium salts are preferred. Further, the amount of cation conversion refers to polyvinyl alcohol containing 0.01 mol% or more. The preferred range of the cation conversion amount is 0.1 to 3
0 mol%. Furthermore, 0.1 to 15 mol% is preferable. If the amount of modification of the cationic group is less than 0.01 mol%, the water resistance of the coating film becomes insufficient, which is not preferable. The average degree of saponification is preferably from 40 to 100 mol%. Saponification degree 40
If it is less than mol%, the ink absorbency becomes insufficient. The average degree of polymerization is preferably from 100 to 5000. And 2
00-3000 is preferred. If the average degree of polymerization is less than 100, the water resistance of the coating film is reduced. If it exceeds 5,000, the solution viscosity is too high, and workability such as mixing of a resin and coating on a support is deteriorated.

The mixing ratio of the carboxyalkyl cellulose nitrate and the aqueous polymer that can be used in the present invention is 3 to 80% by weight of the carboxyalkyl cellulose nitrate and 20 to 97% by weight of the aqueous polymer in terms of solid content. preferable. If the amount of the carboxyalkyl cellulose nitrate is less than 3% by weight, the water resistance of the coating film becomes insufficient.
When the content is 0% by weight or more, the film-forming property is reduced.

As the antistatic agent used in the present invention, known additives can be used as long as the properties of the present invention are not impaired.
A hydroxyl group crosslinking agent such as an aldehyde compound, a melamine resin, an activated vinyl compound, an acid anhydride, an isocyanate compound, an activated vinyl compound, and a polyvalent metal-containing compound can be used for the purpose of improving the strength and water resistance of the coating film. Among these, a melamine resin is preferable, and a methylol melamine derivative such as methylated methylol melamine etherified with a lower alcohol is more preferably used.

For the purpose of improving the ink fixing property, an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used. Examples of anionic surfactants include fatty acid soaps, N-acyl amino acids and salts thereof, alkyl ether carboxylates, carboxylates such as acylated peptides, sulfated oils, higher alcohol sulfates, alkyl ether sulfates, Polyoxyethylene alkyl phenyl ether sulfate, sulfate such as fatty acid alkylol amide sulfate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfo acetate, α-olefin sulfonic acid Sulfonates such as salts, and phosphoric ester salts such as an alkyl ether phosphate salt and an alkyl phosphate salt, and the like.

Examples of the cationic surfactant include aliphatic primary amine salts, secondary amine salts, tertiary amine salts, quaternary ammonium salts, benzalkonium salts, benzenetonium chloride, and pyridinium. Salts, imidazolinium salts and the like. Examples of the amphoteric surfactant include a carboxybetaine type, an aminocarboxylic acid type, an imidazolinium betaine type, and a lecithin type.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether type, polyoxyethylene alkyl phenyl ether type, polyoxyethylene sterol ether type, polyoxyethylene lanolin derivative type, polyoxyethylene glycerin fatty acid ester type,
Polyoxyethylene sorbitan fatty acid ester type, polyoxyethylene sorbitol fatty acid ester type, polyethylene glycol fatty acid ester type, fatty acid glyceride type, polyglycerin fatty acid ester type, sorbitan fatty acid ester type, propylene glycol fatty acid ester type, fatty acid alkanolamide type, polyoxy Examples thereof include an ethylene fatty acid amide type, a polyoxyethylene alkylamine type, and an alkylamine oxide type. Of these, nonionic surfactants are preferable, and sorbitan ester ethers such as polyoxyethylene sorbitan fatty acid ester type and polyoxyethylene sorbitol fatty acid ester type, and polyoxyethylene alkylphenyl ether type are particularly preferable.

The amount of the surfactant added is preferably 0.1% by weight to 20% by weight, more preferably 0.1% by weight to 10% by weight, based on the total amount of the carboxyalkyl cellulose nitrates and the aqueous polymer. % By weight. When the content is less than 0.1% by weight, the effect of improving image clarity is not remarkable, and when it is more than 20% by weight, ink bleeding may occur. In order to improve the fixing property of the dye in the ink, cationized cellulose derivatives, cationized starch, cationized guar gum, diallyl quaternary ammonium salt polymer, copolymer of diallyl quaternary ammonium salt and acrylamide, aniline resin, polythiol Water-soluble cationized polymers such as urea, polyethyleneimine and polyvinylpyridines can be added. A preferable addition amount is 20% by weight or less based on the solid content of the entire coating liquid. More preferably 10% by weight
It is as follows. When the amount of the water-soluble cationized polymer is 20
If the content is more than the weight percentage, gelation and phase separation may occur.
A pH adjuster can be used for the purpose of improving the water resistance of the coating film. As the pH adjuster, an inorganic acid or an organic acid can be used, but an organic acid is preferred from the viewpoint of the stability of the coating solution. Among them, the logarithmic value of the reciprocal of the acid dissociation constant in water at 25 ° C. is 1 to 1.
Six organic acids are preferred. In this case, the logarithmic value of the reciprocal of the acid dissociation constant indicates the value of the first stage dissociation regardless of the monobasic acid or the n-basic acid. Examples of these organic acids include oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, dicarboxylic acids such as itaconic acid, fatty acids such as formic acid, acetic acid, propionic acid, and butyric acid, glycolic acid, lactic acid, and malic acid. And oxyacids such as tartaric acid and citric acid. Preferred p of the coating liquid obtained using the pH adjuster
H is 2 to 8, more preferably 4 to 7. pH 8
If the pH exceeds 2, the effect of improving the water resistance of the coating film is low, and if the pH is less than 2, the workability such as thickening of the solution occurs, and the workability decreases. In addition, matting agents such as calcium carbonate, basic magnesium carbonate and crystalline cellulose, defoaming agents, coating improvers, thickeners, antistatic agents, antioxidants, ultraviolet absorbers, dyes, lightfastness improvers, And a storage stability improver. These are 2
More than one species can be used in combination.

The thickness of the antistatic agent of the present invention which can be provided on the support varies depending on the purpose, but is preferably 0.1 to 5%.
0 μm is good. Preferably it is 1 to 25 μm. When the thickness is less than 0.1 μm, the antistatic property and the ink fixing property decrease, and when the thickness exceeds 50 μm, coating becomes difficult. The nitrates of carboxyalkyl cellulose used in the present invention can be dissolved in water and / or an organic solvent containing water as a main component. The carboxyl groups contained in the carboxyalkyl cellulose nitrates may be partially or completely neutralized in order to increase their solubility in solvents. For neutralization, alkali metal ions, alkaline earth metal ions, ammonium ions,
One or more cations such as organic amines can be used. In this case, the degree of neutralization is arbitrarily determined according to the composition of the target solution such as water and an organic solvent. Generally, 50% or more of the carboxyl groups contained are neutralized. Is preferred. Neutralizing the carboxyalkylcellulose nitrates lowers the viscosity of the solution and improves the coatability of the support.

The organic solvent usable for dissolving the carboxyalkyl cellulose nitrates usable in the present invention includes alcohols, polyhydric alcohols, derivatives of polyhydric alcohols, ketones, esters, carbonates and the like. Solvents comprising one or a combination of two or more selected from among them. As alcohols,
Examples include methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonyl alcohol, n-decanol, n-undecanol or isomers thereof, cyclopentanol, cyclohexanol and the like. Preferably, the alkyl carbon number is 1-6.
Alcohols. Polyhydric alcohols include ethylene glycol, propylene glycol,
1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, glycerin, pentaerythritol and the like can be mentioned. Derivatives of polyhydric alcohols include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol isobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl Ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, cellosolve acetate, etc., or Solvent Pocket Book (p. 479-p, 574), edited by The Society of Synthetic Organic Chemistry, Japan (published by Ohmsha on September 20, 1990). The polyhydric alcohols and derivatives thereof mentioned are mentioned. Examples of ketones include acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diisopropyl ketone, cyclopentanone, cyclohexanone and the like. As the esters, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, lactate ester, butyrate ester, dibutyl phthalate, dioctyl phthalate, and cyclic compounds such as ε-caprolactone and ε-caprolactam Esters are mentioned. Examples of the ethers include diethyl ether, isopropyl ether, n-butyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, and the like. Examples of the carbonates include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate and the like.

The support that can be used in the present invention is not particularly limited as long as it has a possibility of being charged, such as a synthetic resin film, synthetic paper, metal, or general paper. As the synthetic resin film, for example, polyester, polyolefin, polyamide, polyester amide, polyether,
Polyimide, polyamide imide, polystyrene, polycarbonate, poly-P-phenylene sulfide, polyetherester, polyvinyl chloride, polyvinyl acetate, poly (meth) acrylate, and the like can be used. Further, a copolymer, a blend thereof, a further cross-linked product, a film which is made opaque by kneading a pigment, a foamed film, a glossy film, and the like can be used.

The method of applying the antistatic agent of the present invention to the support is as follows: air doctor coater, rod coater, knife coater, reverse roll coater, transfer roll coater, kiss coater, cast coating, spray coater, slot orifice coater, calendar Known methods such as a coater, a blade coater, a gravure coater, a curtain coater, and a roll coater can be applied. At this time, the coatability is improved by subjecting the support to a known surface treatment such as corona discharge treatment or primer treatment in the air or other atmosphere, if necessary, before coating. If necessary, an antistatic agent may be applied to both sides of the support, or a coating having different physical properties may be laminated on the support. The concentration of the coating solution and the conditions for drying the coating film are not particularly limited, but the drying conditions for the coating film are desirably in a range that does not adversely affect the properties of the substrate.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples. In addition, the measuring method of various characteristics in the present invention is as follows. [Measurement method of charge rate] STATIC HONESTME
TER TYPE s-5109 (manufactured by Shisido Electrostatic Co., Ltd.)
The measurement was performed at 27 ° C. and RH = 55% under the conditions of an initial voltage of 11.2 kV and a measurement range of 25 mV. The charging rate at this time was determined from the half life of the decay curve.

T = Rc.C.ln2 t: half-life, Rc: wetting resistance, C: capacitance [Evaluation method of ink fixing property] Coating an antistatic agent with an ink jet printer (PM700C; manufactured by Seiko Epson Corporation) Solid printing is performed on the support thus prepared, and the sharpness of the printed surface is visually evaluated. (Evaluation) ○: good, △: somewhat good, ×: bad

[0021]

[Production Example 1] Carboxymethylcellulose (Cellogen 5
A; manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; carboxymethyl ether group substitution degree = 0.7), 100 g of sulfuric acid / nitric acid / water (= 5)
5000 g of a mixed acid (9/20/21 parts by weight) is placed in a 5-liter reaction vessel, and a nitrification reaction is carried out at 5 to 10 ° C. for 60 minutes while stirring. The reaction product is deacidified by centrifugation and immediately washed with a large amount of water. The reaction product was dried at 80 ° C. for 2 hours to obtain 120 g of carboxymethyl cellulose nitrate. The nitrate ester substitution degree per anhydroglucose unit of this nitrate ester was found to be 1.9 based on the carboxymethyl ether group substitution degree (0.7) of carboxymethyl cellulose and the measurement of the nitrogen content by a CHN coder. Was.

Next, 100 g of carboxymethylcellulose nitrate having a degree of substitution of 1.9 and a degree of substitution of carboxymethyl ether of 0.7 per unit of anhydrous glucose unit and ion-exchanged water 57 were obtained.
1.4 g and 300 g of isopropyl alcohol were put into a closed mixer and stirred. 10% as a neutralizer
28.6 g of aqueous ammonia was added. The solution was completely dissolved with heating to obtain a solution having a solid content of 10% (this is referred to as a binder solution A).

[0023]

[Production Example 2] 100 g of polyvinyl alcohol (KP08: manufactured by Nippon Synthetic Chemical Co., Ltd.), 800 g of ion-exchanged water, and 100 g of isopropyl alcohol were placed in a mixer and stirred until completely dissolved to obtain a solution having a solid content of 10%. (This is called binder liquid B).

[0024]

[Production Example 3] Cation-modified polyvinyl alcohol (CM
318: Kuraray Co., Ltd., polymerization degree 1700, saponification degree 86-9
1 g, a cationic group content of 1-3 mol%), 100 g of ion-exchanged water, and 100 g of isopropyl alcohol were put into a mixer, and stirred until completely dissolved.
% Solution (this is referred to as a binder liquid C).

[0025]

Example 1 An antistatic agent was prepared by mixing a binder liquid A and a binder liquid B at a weight ratio of 50:50. An antistatic agent is coated on a transparent polyethylene terephthalate film (Melinex D535) having a thickness of 100 μm with a rod coater so as to have a thickness of 10 μm.
The test piece was obtained by drying for 5 minutes. The evaluation results of the charging rate and the ink fixing property are as follows. Charge rate: 13.5 seconds, ink fixability: Δ

[0026]

Example 2 A test piece was obtained in the same manner as in Example 1 except that the mixing ratio of the binder liquid A and the binder liquid B was changed to 70:30. The evaluation results of the charging rate and the ink fixing property are as follows. Charge rate: 2.5 seconds, ink fixability: △

[0027]

Example 3 A test piece was obtained in the same manner as in Example 1 except that the mixing ratio of the binder liquid A and the binder liquid B was changed to 80:20. The evaluation results of the charging rate and the ink fixing property are as follows. Charge rate: 1 second, ink fixability: △

[0028]

Example 4 A test piece was obtained in the same manner as in Example 1 except that the mixing ratio of the binder liquid A and the binder liquid B was changed to 90:10. The evaluation results of the charging rate and the ink fixing property are as follows. Charge rate: 0.5 seconds, ink fixability: △

[0029]

Example 5 An antistatic agent was prepared by mixing the binder liquid A and the binder liquid C at a weight ratio of 20:80. An antistatic agent is coated on a transparent polyethylene terephthalate film (Melinex D535) having a thickness of 100 μm with a rod coater so as to have a thickness of 10 μm.
The test piece was obtained by drying for 5 minutes. The evaluation results of the charging rate and the ink fixing property are as follows. Charging rate: 200 seconds, ink fixability: ○

[0030]

[Comparative Example 1] Nitrified cotton (HIG1 / 2, manufactured by Asahi Kasei) 250
g and 750 g of the JIS solvent were placed in a mixer and stirred until completely dissolved to obtain a 25% nitrified cotton solution. Dibutyl phthalate was added to this solution in an amount of 5% based on the solid content to obtain a coating liquid. This coating liquid was applied to a transparent polyethylene terephthalate film having a thickness of 100 μm so that the film thickness became 14 μm, and dried, to obtain a test piece. The evaluation results of the charging rate and the ink fixing property are as follows.

Charge rate: 17.7 hours, ink fixability: ×

[0032]

Comparative Example 2 A test piece was obtained in the same manner as in Comparative Example 1 except that the amount of dibutyl phthalate added to nitrified cotton was changed to 20%. The evaluation results of the charging rate and the ink fixing property are as follows. Charge rate: 20 hours, ink fixability: ×

[0033]

According to the present invention, a high antistatic property can be obtained by containing at least a nitrate of carboxyalkyl cellulose. Furthermore, by using a water-soluble polymer other than nitric acid esters of carboxyalkylcellulose in combination, better ink fixing properties are exhibited, and antistatic properties and designability by printing can be imparted. In particular, it is useful for aqueous inks such as ink jet recording inks. The antistatic agent of the present invention can be applied to base materials that easily hold static electricity, such as prepaid cards, key chains, and door knobs.

Claims (1)

[Claims] 1. A nitric acid ester of carboxyalkylcellulose having a degree of substitution of nitric acid ester groups per anhydroglucose unit of 0.2 to 2.95 and a degree of substitution of carboxyalkyl ether groups of 0.05 to 2.8. An antistatic agent characterized by containing.