JP2006111699A - Pigment dispersion paste for electrodeposition coating and electrodeposition coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrodeposition coating that improves the storage stability of a pigment dispersion paste for an electrodeposition coating and can deal with the energy saving and the facility saving of a coating facility of an electrodeposition coating. <P>SOLUTION: The pigment dispersion paste for an electrodeposition coating comprises a resin for pigment dispersion, a pigment and 0.1-25 parts wt. of a cellulose complex based on 100 parts wt. of the total of solid content of the resin for pigment dispersion and the pigment. The electrodeposition coating comprises a base resin, a curing agent and 0.1-20 parts wt. of a cellulose complex based on 100 parts wt. of the total of solid content of the base resin and the curing agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pigment dispersion paste for electrodeposition paints excellent in storage stability, and an electrodeposition paint that enables energy saving and equipment saving of coating equipment.

  Electrodeposition paints are widely used as undercoat paints for metal products such as automobile bodies because they have excellent paint workability and good rust prevention. The pigment-dispersed paste used in this electrodeposition coating is usually stored in a tank after production or stored in a warehouse in a drum can. However, if it is not stirred regularly, the pigment may settle and hinder use. is there. In particular, when transporting to an overseas coating facility, the pigment dispersion paste placed in a drum can is exposed to a non-stirring state for a long period of time, so it is an urgent task to improve the storage stability of the pigment dispersion paste. ing.

  On the other hand, electrodeposition paints usually circulate and agitate with a pump during breaks, nights and holidays in order to prevent pigment settling. However, the installation and maintenance of such equipment is enormous. Therefore, there is a need for an electrodeposition coating material that can cope with energy saving and equipment saving of coating equipment.

In order to meet such demands, an electrodeposition paint that uses carbon black having a low specific gravity as a pigment and a liquid tin catalyst as a curing catalyst and has almost no precipitation of the pigment during standing storage has been proposed. (See Patent Document 1). However, in this electrodeposition paint, since a liquid tin catalyst is blended in the emulsion, there is a problem in the storage stability of the emulsion and the paint stability of the electrodeposition paint, and because carbon black is used as a pigment, There is a problem that the paint color is limited to black.
JP 2004-123942 A

  An object of the present invention is to provide a pigment-dispersed paste for an electrodeposition paint having excellent storage stability.

  Another object of the present invention is to provide an electrodeposition paint that is excellent in redispersibility and paint stability and can be applied in a wide range of paint colors even when the stirring and circulation of the paint is stopped during breaks, holidays, and nighttime. It is.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above object can be achieved by blending a cellulose composite with a pigment-dispersed paste or an electrodeposition paint, and completed the present invention. It came to do.

  Thus, the present invention provides a pigment dispersion paste for electrodeposition paints containing 0.1 to 25 parts by weight of a cellulose composite per 100 parts by weight of the total solid content of the pigment dispersion resin, pigment and pigment dispersion resin and pigment. To do.

  The present invention also provides an electrodeposition coating material containing 0.1 to 20 parts by weight of a cellulose composite per 100 parts by weight of the total solid content of the base resin, the curing agent and the base resin and the curing agent.

  Since the pigment dispersion paste for electrodeposition paints of the present invention is excellent in storage stability, it is possible to save labor and cost for stirring during storage, and it can be stored in a tank or drum without stirring. However, since the redispersibility of the pigment is excellent, a coated article having excellent finish can be provided.

  The electrodeposition paint of the present invention is excellent in the redispersibility of paint when the paint is stirred and circulated for a long time on holiday or at night and then restarted. Energy saving operation and equipment saving such as reducing the number of units are possible.

  Hereinafter, the pigment dispersion paste for electrodeposition paint and the electrodeposition paint of the present invention will be described in more detail.

Pigment Dispersion Paste The pigment dispersion paste of the present invention basically comprises a pigment dispersion resin and a pigment, and further contains a cellulose composite.

  The cellulose composite is a composite made of fine cellulose and water-soluble gums and / or hydrophilic substances, and is a composite made of fine cellulose, water-soluble gums and hydrophilic substances; fine cellulose and water-soluble gums And a composite composed of fine cellulose and a hydrophilic substance. For example, a water-soluble gum and / or a hydrophilic substance is added to and dispersed in fine cellulose obtained by grinding cellulose. It can be made by forming a homogeneous slurry and then drying it.

  The fine cellulose is, for example, cellulose having an average degree of polymerization of 30 to 375 by depolymerizing cellulose-based materials such as wood pulp and refined linter by acid hydrolysis, alkaline oxidative decomposition, enzymatic decomposition, steam explosion decomposition and the like. And then grinding, for example by wet grinding with mechanical shear.

The wet grinding can be performed using a medium mill, for example, a wet vibration mill, a wet planetary vibration mill, a wet ball mill, a wet roll mill, a wet ball mill, a wet bead mill, a wet paint shaker, or a machine such as a high-pressure homogenizer. it can. As the high-pressure homogenizer, a type in which the slurry is guided to a fine orifice at a high pressure of about 500 Kg / cm ² or more and collides with each other at a high flow rate is effective.

  The optimum grinding concentration in these mills varies depending on the model, but in general, a solid content concentration in the range of 5 to 15% for a medium mill and 5 to 20% for a high-pressure homogenizer is suitable. A medium mill is suitable for efficiently grinding cellulose.

  By the above grinding, fine cellulose having an average particle size of 10 μm or less, preferably 8 μm or less, more preferably 5 μm or less can be obtained. In addition, an average particle diameter is a value when it measures using the laser diffraction type particle size distribution analyzer LA-920 (made by Horiba Ltd.).

  The resulting fine cellulose is mixed with water-soluble gums and / or hydrophilic substances to form a composite. Thereby, it can prevent that the cellulose particle refined | miniaturized at the time of drying reaggregates.

  As the water-soluble gums, water-soluble gums having high water swellability and good compatibility with water in cellulose are preferable. For example, locust bean gum, guar gum, tamarind gum, quince seed gum, karaya gum, gum arabic gum , Tragacanth gum, ghatti gum, arabinogalactan, agar, carrageenan, alginic acid and its salts, ferceleran, pectin, quince, xanthan gum, curdlan, pullulan, dextran, gellan gum, gelatin, cellulose derivatives such as cellulose glycolate, etc. be able to. Among these, sodium cellulose glycolate has both swellability and hydrophilicity, so that it can be used alone without using a hydrophilic substance.

  On the other hand, examples of hydrophilic substances include water, starch hydrolysates, dextrins, glucose, fructose, xylose, sucrose, lactose, maltose, isomerized sugar, coupling sugar, palatinose, neosugar, mannitol, and reduced starch saccharification. Examples thereof include monosaccharides such as koji, maltose, lactulose, polydextrose, fructooligosaccharide, and galactooligosaccharide, water-soluble saccharides including oligosaccharide, sugar alcohols such as xylitol, maltitol, mannitol, and sorbitol, and sorbose.

  The hydrophilic substance promotes dispersion of cellulose in water, and has a remarkable effect on dispersibility or dispersion stability by combining with water-soluble gums.

  The proportion of fine cellulose in the cellulose composite is generally in the range of 0.1 to 99% by weight, preferably 1 to 95% by weight, more preferably 10 to 85% by weight, based on the solid content of the cellulose composite. It is preferable from the viewpoint of paint stability. The ratio of the water-soluble gum and the hydrophilic substance used in combination is usually 95/5 to 5/95, preferably 80/20 to 20 / in terms of the weight ratio of the water-soluble gum / hydrophilic substance. It can be in the range of 80.

  The cellulose composite can be produced by mixing and dispersing finely divided cellulose with water-soluble gums and / or hydrophilic substances, followed by drying. In this case, in particular, water-soluble gums are sufficiently dissolved. It is important to mix uniformly. In order to promote dissolution and complexing, heat treatment may be performed.

  Although drying can also be performed by freeze-drying, spray drying, etc., the method of drying in a film form is excellent, for example. Examples of the method of drying in a film form include, for example, a slurry obtained by uniformly mixing finely divided cellulose together with water-soluble gums and / or hydrophilic substances, such as glass, stainless steel, aluminum, nickel / chromium plated steel plates, and the like. The method of apply | coating on a material and drying is mentioned. The substrate may be heated in advance, or may be heated with infrared rays, hot air, high frequency, or the like after application. The drying temperature is preferably 200 ° C. or less, and the coating film thickness is preferably 10 mm or less as the thickness of the slurry. Industrially, dry powder can be obtained using a dryer such as a steel belt dryer, drum dryer, or disk dryer.

  When the dry powder thus obtained is observed with an electron microscope, the finely divided cellulose is arranged in a mesh pattern on the surface, and numerous voids are observed between the finely divided celluloses.

  As a commercial item of the cellulose composite obtained as mentioned above, Avicel RC-N81, Avicel RC-N30, Avicel RC-591, Avicel CL-611, Theorasu Cream FP-03 (above, manufactured by Asahi Kasei Chemicals Corporation) , Product name).

  Cellulose composites have the ability to stably disperse without settling in water, and when applied to electrodeposition paints, when the paint is stirred and circulated for a long time on holidays or at night, A paint excellent in redispersibility of paint and finish of paint film can be obtained.

  Introduction of the cellulose composite into the electrodeposition paint can be carried out in the same manner as the blending of the pigment into the ordinary electrodeposition paint. For example, a resin for dispersing the pigment and the pigment, and optionally a curing catalyst, neutralization, etc. It can be carried out by blending an agent, a surfactant, water and the like, adding a cellulose composite, and dispersing the pigment to prepare a pigment dispersion paste. The pigment dispersion can be performed using a dispersing machine such as a ball mill, a pebble mill, a sand mill, or a shaker.

  As the pigment dispersion resin, those usually used for the preparation of electrodeposition paints can be used. For example, an amino group-containing epoxy resin such as a tertiary amine type, a quaternary ammonium salt type epoxy resin, and a quaternary ammonium salt type. An acrylic resin etc. are mentioned.

  As the pigment, those usually used for electrodeposition paints can be used as well, and examples of the color pigment include carbon black, perylene black, titanium oxide, phthalocyanine blue, phthalocyanine green, and ocher. When the coating color for parts and the like is black, carbon black, perylene black and the like are preferable. Examples of extender pigments include clay, mica, talc, barita, and silica, and examples of rust preventive pigments include phosphomolybdate and aluminum tripolyphosphate. In addition, for example, bismuth oxide, bismuth hydroxide, basic bismuth carbonate, bismuth nitrate, bismuth silicate, hydrotalcite, zinc compounds, and the like can also be used.

  The curing catalyst appropriately blended is effective for promoting the crosslinking reaction of the coating film, and examples thereof include dioctyltin oxide, dibutyltin oxide, tin octoate, dibutyltin dilaurate, and dibutyltin dibenzoate.

  The blending amount of the cellulose composite in the pigment dispersion paste is generally 0.1 to 25 parts by weight, preferably 0.3 to 10 parts by weight, more preferably 100 parts by weight of the total solid content of the pigment dispersion resin and the pigment. It can be in the range of 0.5 to 5 parts by weight. The amount of the pigment dispersing resin is usually 5 to 30%, preferably 10 to 25% based on the weight of the pigment dispersing paste, and the pigment is usually 30 to 60%, preferably 40 to 50%. % Range.

  The pigment-dispersed paste thus obtained is excellent in redispersibility even when stored in a container or drum and stored for a long time without stirring, so that it can be stored for a long period of time and transported over a long distance.

Electrodeposition Paint The pigment dispersion paste provided by the present invention can be mixed with an emulsion containing a base resin and a curing agent to produce an electrodeposition paint.

  In general, the cellulose composite is preferably blended into the pigment dispersion paste and introduced into the electrodeposition paint, but can be blended into the electrodeposition paint at any stage of the preparation of the electrodeposition paint. Or it can also be directly blended in the form of a dispersion formed by mixing water and a cellulose composite, for example, with an electrodeposition paint containing a base resin and a curing agent prepared in advance.

  The blending ratio of the cellulose composite with respect to the electrodeposition paint is generally 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight per 100 parts by weight of the total solid content of the base resin and the curing agent in the electrodeposition paint. The range of 0.5 to 8 parts by weight is preferable from the viewpoints of paint stability and finish.

  The electrodeposition paint may be either an anionic type or a cationic type, but in general, a cationic type is preferred from the viewpoint of corrosion resistance. Further, as the base resin, for example, any resin for paint such as epoxy resin, acrylic resin, polybutadiene resin, alkyd resin, polyester resin, etc. can be used. The polyamine resin represented by is preferable.

  An amine-added epoxy resin is obtained by adding an amine compound to an epoxy resin, and as an epoxy resin used in that case, from the viewpoint of anticorrosiveness of a coating film, in particular, a polyphenol compound and an epihalohydrin, for example, Epoxy resins obtained by reaction with epichlorohydrin are preferred.

  As the polyphenol compound that can be used for the formation of the epoxy resin, the same as those conventionally used can be used, for example, bis (4-hydroxyphenyl) -2,2-propane (bisphenol A), 4,4-dihydroxybenzophenone, bis (4-hydroxyphenyl) methane (bisphenol F), bis (4-hydroxyphenyl) -1,1-ethane, bis (4-hydroxyphenyl) -1,1-isobutane, bis ( 4-hydroxy-tert-butyl-phenyl) -2,2-propane, bis (2-hydroxynaphthyl) methane, tetra (4-hydroxyphenyl) -1,1,2,2-ethane, 4,4-dihydroxydiphenyl Examples include sulfone (bisphenol S), phenol novolac, cresol novolac, etc. That.

  Moreover, as an epoxy resin obtained by reaction of a polyphenol compound and epichlorohydrin, the following formula induced | guided | derived from bisphenol A is mentioned especially,

Those represented by are preferred.

  The epoxy resin can generally have an epoxy equivalent weight in the range of 180 to 2,500, preferably 200 to 2,000, more preferably 400 to 1,500, and is generally at least 200, in particular 400 to 4, Those having a number average molecular weight in the range of 000, more particularly in the range of 800 to 2,500 are suitable.

  Examples of such commercially available epoxy resins include those sold by Japan Epoxy Resins Co., Ltd. under the trade names of Epicoat 828EL, 1002, 1004, and 1007.

  The amine compound is a cationic component that cationizes the epoxy resin by introducing an amino group into the epoxy resin, and contains at least one active hydrogen that reacts with the epoxy group, for example, a primary amino group An amine compound having the following formula is used.

  Examples of the amine compound having a primary amino group include ketiminates such as monoethanolamine, propanolamine, hydroxyethylaminoethylenediamine, hydroxyethylaminopropylamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Can be mentioned.

  The amine compound having a primary amino group can be used in combination with other amine compounds, and as the amine compound that can be used in combination, a secondary amine is particularly preferable. For example, diethylamine, diisopropylamine, diethanolamine, di (2 -Hydroxypropyl) amine, monomethylaminoethanol, monoethylaminoethanol and the like.

  The above epoxy resin can be modified by reacting with xylene formaldehyde resin, caprolactone polyol compound or the like.

  The xylene formaldehyde resin can be produced, for example, by subjecting xylene, formaldehyde, and optionally phenols to a condensation reaction in the presence of an acidic catalyst. Examples of the formaldehyde include compounds that generate formaldehyde such as formalin, paraformaldehyde, and trioxane, which are industrially easily available. The xylene formaldehyde resin can generally have a viscosity in the range of 20 to 50,000 centipoise (25 ° C.), preferably 30 to 15,000 centipoise (25 ° C.), and generally 100 to 50,000, especially It preferably has a hydroxyl equivalent weight within the range of 200 to 10,000.

  On the other hand, the caprolactone polyol compound can be obtained by adding caprolactone to a compound containing a plurality of active hydrogen groups, for example, ethylene glycol, propylene glycol, trimethylolpropane and the like.

  In general, modification of an epoxy resin with a xylene formaldehyde resin or a polycaprolactone polyol compound is preferably performed by reacting an amine compound and a modifier simultaneously with an epoxy group of the epoxy resin.

  The use ratio of the above modifier is not strictly limited and can be appropriately changed according to the use of the coating composition, etc., but is generally 5 to 50 weights based on the solid content weight of the epoxy resin. %, Preferably in the range of 10 to 30% by weight.

  Conventionally known curing agents such as blocked polyisocyanate compounds and amino resins can be used as the curing agent to be blended in the cationic electrodeposition coating, and blocked polyisocyanate compounds are particularly preferred.

  Examples of the polyisocyanate compound include aromatic, alicyclic or aliphatic such as tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, bis (isocyanate methyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, and isophorone diisocyanate. Polyisocyanate compounds and excess isocyanate compounds include terminal isocyanate-containing compounds obtained by reacting low molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol, and castor oil. .

  Examples of the blocking agent include lactam compounds such as ε-caprolactam and γ-butyrolactam; oxime compounds such as methyl ethyl ketoxime and cyclohexanone oxime; phenol compounds such as phenol, para-t-butylphenol and cresol; n-butanol, Examples thereof include aliphatic alcohols such as 2-ethylhexanol; aromatic alkyl alcohols such as phenyl carbinol and methyl phenyl carbinol; ether alcohol compounds such as ethylene glycol monobutyl ether. Of these, oxime-based and lactam-based blocking agents are blocking agents that dissociate at relatively low temperatures, and are particularly suitable from the viewpoint of low-temperature curability.

  The amount of the base resin and the curing agent used is 60 to 90%, preferably 70 to 85%, and the curing agent is 40 to 10%, preferably 30 to 15% based on the total weight of both. % Range.

  The above-mentioned base resin and curing agent can usually be made into an emulsion by neutralizing the resin with a water-soluble organic acid such as formic acid, acetic acid, or lactic acid to make it water-soluble or water-dispersed.

  Cationic electrodeposition paints can be prepared by adding a pigment dispersion paste to an emulsion and, if necessary, blending additives such as organic solvents, surfactants, surface conditioners, anti-fogging agents, etc. A bath of cationic electrodeposition paint is obtained by diluting with deionized water or the like so that the solid content concentration is in the range of 5 to 25% by weight and adjusting the pH in the range of 5.0 to 7.0. be able to.

  Electrodeposition coating can usually be performed under conditions of a bath temperature of 15 to 35 ° C. and an applied voltage of 100 to 400V.

  The film thickness of the electrodeposition coating film is not particularly limited, but generally it is preferably within the range of 10 to 40 μm based on the cured coating film. Moreover, generally the baking conditions of a coating film are suitable for 5-90 minutes within the range of 100-200 degreeC.

  The electrodeposition paint of the present invention has excellent paint redispersibility and paint stability when the paint line is stirred and circulated for a long time on holidays and at night and then restarted. Is possible.

  The electrodeposition coating material of the present invention forms a cured coating film excellent in anticorrosion properties, suitability for electrodeposition coating on a steel plate for rust prevention, adhesion to a base material, and the like, even though a cellulose composite is blended. For example, it is useful as an undercoating paint in the fields of automobile bodies, automobile parts, industrial, construction and construction.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited only to these Examples. “Parts” and “%” indicate “parts by weight” and “% by weight”.

Production Example 1
A commercially available pulp (DP pulp) is shredded, hydrolyzed in 105% hydrochloric acid at 105 ° C. for 20 minutes, and the resulting acid-insoluble residue is filtered and washed. Obtained.

  This cellulose dispersion was fed with a medium stirring wet pulverizer (Apex Mill, manufactured by Kotobuki Giken Kogyo Co., Ltd., AM-1 type) using a zirconia bead with a diameter of 1 mmφ as a medium and a rotation speed of the stirring blade of 1800 rpm Pulverization was performed by passing twice under the condition of an amount of 0.4 l / min to obtain pasty cellulose. The average particle size was 3.1 μm.

  Next, cellulose, xanthan gum, and glucose were mixed such that the blending composition was 75/5/20 in terms of the solid content ratio to obtain a dispersion having a total solid content concentration of 3.5%. The mixture was heat-treated at 80 ° C. for 60 minutes with stirring, and then spray-dried to obtain cellulose composite no. 1 was obtained.

Production Example 2
In a ball mill, 8.33 parts of 60% epoxy-based quaternary ammonium salt type pigment dispersion resin (solid content 5 parts), composite no. 1 0.25 parts, titanium white 16.5 parts, clay 8 parts, carbon black 0.3 parts, bismuth hydroxide 2 parts, dioctyltin oxide 1 part and deionized water 23.7 parts are charged and dispersed for 20 hours. Pigment paste No. 55 having a solid content of 55%. 1 was obtained.

Production Examples 3-7
In the same manner as in Production Example 2, the pigment dispersion paste No. 2-No. 6 was obtained.

(Note 1) Avicel RC-N81: Asahi Kasei Chemicals Corporation, trade name, cellulose composite (crystalline cellulose, Karaya gum, dextrin)
(Note 2) Avicel RC-N30: Asahi Kasei Chemicals Corporation, trade name, cellulose composite (crystalline cellulose, xanthan gum, dextrin)
(Note 3) Theolas cream FP-03: manufactured by Asahi Kasei Chemicals Corporation, trade name, cellulose composite (crystalline cellulose, water)

Production Example 8
A reaction vessel equipped with a thermometer, thermostat, stirrer and reflux condenser was charged with 380 parts of Epicoat 828EL (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy resin, epoxy equivalent of about 190) and 137 parts of bisphenol A and heated to 100 ° C. Then, 0.26 part of N-benzyldimethylamine was added, the temperature was raised to 120 ° C., and the reaction was allowed to proceed for about 2 hours. Then, 120 parts of methyl isobutyl ketone was blended, cooled to 80 ° C., 14 parts of methyl isobutyl diketimine of diethylenetriamine (75% solution of methyl isobutyl ketone) and 57 parts of N-ethyl monoethanolamine were blended, and up to 100 ° C. The mixture was heated and heated for about 5 hours, and then 41 parts of propylene glycol monomethyl ether was added. 1 was obtained.

Production Example 9
A separable flask having an internal volume of 2 liters equipped with a thermometer, a reflux condenser and a stirrer was charged with 240 parts of 50% formalin, 55 parts of phenol, 101 parts of 98% industrial sulfuric acid and 212 parts of metaxylene, and 84 to 88 ° C. For 4 hours. After the reaction is completed, the resin phase is separated from the sulfuric acid aqueous phase by standing, then the resin phase is washed with water three times, and unreacted metaxylene is stripped for 20 minutes under the condition of 20-30 mmHg / 120-130 ° C. 240 parts of a phenol-modified xylene formaldehyde resin having a viscosity of 1050 centipoise (25 ° C.) were obtained.

  To another flask, 1000 parts of Epicoat 828EL (trade name, epoxy resin, epoxy equivalent 190, molecular weight 350, manufactured by Japan Epoxy Resin Co., Ltd.) 1000 parts, 400 parts of bisphenol A and 0.2 parts of dimethylbenzylamine were added, and the epoxy equivalent at 130 ° C. The reaction was continued until 750.

  Next, 300 parts of phenol-modified xylene formaldehyde resin, 140 parts of diethanolamine and 65 parts of diethylenetriamine ketimine compound were added and reacted at 120 ° C. for 4 hours. Then, 420 parts of ethylene glycol monobutyl ether was added and xylene having a solid content of 80% was added. Substrate resin No. which is a formaldehyde resin-modified amino group-containing epoxy resin 2 was obtained.

Production Example 10
270 parts of Cosmonate M-200 (trade name, Crude MDI, manufactured by Mitsui Chemicals, Inc.) and 25 parts of methyl isobutyl ketone were added to the reaction vessel, and the temperature was raised to 70 ° C. Thereto, 15 parts of 2,2-dimethylolbutanoic acid was gradually added, and then 118 parts of ethylene glycol monobutyl ether was added dropwise, reacted at 70 ° C. for 1 hour, cooled to 60 ° C., and propylene glycol. 152 parts were added.

  While maintaining this temperature, sampling was performed over time, and it was confirmed by infrared absorption spectrum measurement that there was no absorption of unreacted isocyanato groups, and a block polyisocyanate curing agent having a resin solid content of 90% was obtained.

Production Example 11
The base resin No. obtained in Production Example 8 was used. 1 87.5 parts (solid content 70 parts), 33.3 parts of the blocked polyisocyanate curing agent obtained in Production Example 10 (solid content 30 parts) and 10% acetic acid 15 parts were mixed and stirred uniformly, and then removed. 158.3 parts of ionic water was added dropwise over about 15 minutes with vigorous stirring, and the emulsion No. 1 was obtained by cationic electrodeposition with a solid content of 34%. 1 was obtained.

Production Example 12
The base resin No. obtained in Production Example 8 was used. 1 instead of the amine-modified epoxy resin No. 1 obtained in Production Example 9. Except for using No. 2, in the same manner as in Production Example 11, emulsion no. 2 was obtained.

Examples 1-5, Comparative Example 1
Pigment dispersion paste Nos. Obtained in Production Examples 2 to 7 1-No. 6 100 g each was taken and stored in a glass container with a lid at 40 ° C. for 4 weeks. The state after storage was evaluated according to the following criteria. The results are shown in Table 2.

(Note 4) Storage stability of pigment dispersion paste: The state of the pigment dispersion paste after storage was observed.
○, after stirring, it returns to the state before storage and there is no problem.
In Δ, the pigment settles and a cake layer is observed, and if it is stirred for about 1 hour, it returns to the state before storage.
In x, a pigment layer settles and a cake layer is seen. If the mixture is stirred for 2 to 3 hours or more, the sedimented cake layer disappears, but pigment aggregation remains in the pigment dispersion paste.

Example 6
Emulsion no. 1 To 294 parts (solid content 100 parts), the pigment dispersion paste No. 1 60.1 parts (solid content 33.1 parts), 10% acetic acid 5.6 parts and deionized water 305.8 parts were added and mixed uniformly to give a cationic electrodeposition paint No. 1 having a solid content of 20%. 1 was obtained.

Examples 7-11, Comparative Example 2
In the same manner as in Example 1, the cationic electrodeposition paint No. 1 was prepared with the formulation shown in Table 3 below. 2-No. 7 was obtained.

Preparation of test plate 0.8 × 150 × 70 mm of chemical conversion treatment with Palbond # 3020 (manufactured by Nippon Parkerizing Co., Ltd., zinc phosphate treating agent) in the cationic electrodeposition paints obtained in Examples 7-12 and Comparative Example 2. Immerse the cold-rolled dull steel plate and use it as a cathode for electrodeposition coating under conditions of a bath temperature of 28 ° C. and an applied voltage of 250 V to form an electrodeposition coating film with a film thickness of 20 μm. After washing with water, baking at 170 ° C. for 20 minutes To obtain a test plate. Table 4 below shows the results of the paint test and the performance test of the test plate.

(Note 5) Filtration residue: After the stirring of the cationic electrodeposition paint was stopped for 24 hours, the mixture was stirred again for 1 hour, and the amount of residue (mg / L) when the paint was filtered using a 400 mesh filter was measured. The evaluation was based on the following criteria.
○: Residual amount is less than 1 mg / L
Δ: Residual amount is 1 to 5 mg / L
X: Residual amount exceeds 5 mg / L.
(Note 6) L-shaped finish: Stirring of the cationic electrodeposition paint was stopped for 24 hours, and then stirred again for 1 hour, using a cold-rolled dull steel sheet subjected to chemical conversion treatment that was bent into an L-shape as the coating object. The electrodeposition coating for 3 minutes was performed and the state of the coating film of the horizontal surface (L surface) was evaluated.
○: No problem
Δ: The repellency, roundness, and gloss of the coating are reduced.
X: The repellency of a coating film, a round feeling, and the gloss fall are remarkable.
(Note 7) Salt warm water resistance: The results when the cross-cut scratches were put on the coated plates obtained in Examples and Comparative Examples with a knife and immersed in 55 ° C, 5% saline for 10 days were evaluated according to the following criteria. It was.
○: The maximum width of rust and blisters is less than 3 mm from the cut part (one side)
Δ: The maximum width of rust and blisters is 3mm or more and less than 4mm from the cut part (one side)
X: The maximum width of rust and blisters is 4 mm or more (one side) from the cut part.
(Note 8) Impact resistance: Tested using a DuPont impact tester under conditions of 1/2 inch diameter of hitting point, height of falling weight 50 cm, and measurement atmosphere 20 ° C. Visual evaluation was made.
Y: No abnormality
Δ: Some small cracks are seen
X: A big crack is seen.

  The electrodeposition paint of the present invention can omit stirring at the time of pigment dispersion pace storage, and can save energy and equipment in the coating line.

Claims (7)

  Pigment dispersion resin, pigment and pigment dispersion paste for electrodeposition paint containing 0.1 to 25 parts by weight of cellulose composite per 100 parts by weight of solid content of pigment dispersion resin and pigment.   The pigment dispersion paste for electrodeposition paints according to claim 1, wherein the cellulose composite is a composite comprising fine cellulose and a water-soluble gum and / or a hydrophilic substance.   The pigment dispersion paste for electrodeposition paints according to claim 2, wherein the average particle size of the fine cellulose is 10 µm or less.   An electrodeposition coating composition containing 0.1 to 20 parts by weight of a cellulose composite per 100 parts by weight of the base resin, the curing agent, and the total solid content of the base resin and the curing agent.   The electrodeposition coating material according to claim 4, wherein the cellulose composite is a composite comprising fine cellulose and a water-soluble gum and / or a hydrophilic substance.   The electrodeposition coating material according to claim 5, wherein the fine cellulose has an average particle size of 10 μm or less.   An article coated with the electrodeposition paint according to any one of claims 4 to 6.