JPS6389581A - Production of pigment paste for water dilution type paint - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a two-component replenishment method for water-reducible paints, particularly in electrodeposition coatings.
ishing method).

In electrocoating, the colorant present in the aqueous medium is electrodeposited with a high solids content onto the substrate and leaves the electrodeposition bath with the coating. Therefore, in order to maintain a suitable concentration of the material in the electrodeposition bath, the electrodeposition bath must be replenished with a corresponding material. This is for example ltleigel, ``Electrophoretic paint (Ele
ktrophoreselack) J, Wissen
schaftl, verlagslQsmbh, St
uttgurt.

(1967) or Yeats r electric painting 51ect
ro-painting) J, R, Draper L
Either the unneutralized highly concentrated pigment-binder paste is replenished, or the free neutralizing agent and excess aqueous medium are removed by a dialysis machine, as previously known in TD, Teddington (1970) and others. This can be done by either of the following methods: then replenishing the diluted paint.

When operating an electrocoat coating plant, in particular a cationic electrocoat coating plant, it is advantageous to add a two-component supplement, namely a highly pigmented colorant component and a clear lacquer (Klarlack) component. One thing has become clear.

This inherently facilitates automatic control in electrodeposition bath operation.

The combination of aqueous pigment paste and clear lacquer dispersion is
U.S. Patent No. 4,035,275, No. 4.081,34
No. 3 or No. 4.186.124. German Patent No. 3.040.419 additionally uses an aqueous catalyst paste as a further component. The product used in this case is used to disperse pigments (dibutyltin oxide is mixed and dispersed in the eardrum).

When using these so-called two-component supplementation methods, 1 ml
The compatibility between the paste resin and the main binder is good, and even if a special stirring device or mixing device is used, an optimum homogeneous mixed product cannot be obtained.

In particular, pigment components containing materials such as crosslinking catalysts, leveling agents, antifoaming agents, etc., which become active when combined with the main binder, do not have sufficient access to the resin micelles of the main binder.

When additives, which are often water-insoluble, are directly mixed with the main binder, the diluted dispersion of electrodeposition bath components can impair its storage stability and reduce the effectiveness of the additives. Become.

It has now been found that the problems described above can be solved by including one or more such additives in the pigment component together with some of the main binder.

Since in this case the additives are present in the micelles of the main binder, they can be dispersed in the clear lacquer component in the main preferred manner.

In particular, "volatile organic compositions (VOC)
When there is a demand from a consumer for a reduction in organic composition, or when it is regulated by many I laws, there are no methods other than those described above to add ingredients in the form of a low-solvent dispersion. Appropriate dispersion cannot be performed.

Therefore, the present invention provides a method for producing a pigment paste for water-dilutable paints, particularly for a two-component replenishment method for electrocoating with catalytically cured paints, in which the resin (A) for pigment paste for paints contains:
All or part of the required catalyst and/or other additives (C) and a part of the main binder for paint (B),
A method for producing a pigment paste characterized by uniformly mixing and dispersing the pigment (D) before or after mixing and dispersing the pigment (D), or before or after neutralizing some or all of the salt-forming groups. It is.

A further object of the invention is the use of the pigment paste produced by the method of the invention in electrodeposition paints, especially cationic electrodeposition paints.

In order for the pigment component of the present invention to be particularly effective, a preferred embodiment includes: (a) 70% to 30% by weight, preferably 70% to 50% by weight of the pigment paste-forming resin (A); 'b) 30% of the main binder (B) for paints, in which all or part of the additive components (C) necessary for paints are mixed uniformly.
% to 70% by weight, preferably 30% to 50% by weight, and after neutralizing all or part of the salt-forming groups, a mixing and dispersing step is carried out subsequently in a mixing and dispersing device after adding the pigment (D). It is characterized by being diluted with water to achieve the optimum viscosity.

However, if desired, the components may be mixed in a different order (N=neutralization, W=water addition), for example as shown in the following formula: (A+N)+(B+C)+W+D, or (A+C)
+N+B+W+D, or (A+8)+N+C+W+D0 In either case, it is essential that the additive be mixed with the resin component before dilution with water and be mixed with the resin component prior to substantial dilution with water. . Furthermore, in all the variants employed in the present invention, it should be avoided to add additives with insufficient water compatibility to the main binder component, which has already been diluted with a large amount of water for make-up. .

The type of primary binder or preferred binder type for producing pigment pastes is known from the literature.

The pigment paste of the invention is particularly suitable for use in paints in which crosslinking is carried out at high temperatures by transesterification, transamidation, transurethane reaction or reaction of terminal double bonds.

Since the above reactions are influenced only by the catalyst, it is of utmost importance to optimize the mixture of catalysts. Representative types of binders include, for example, European Patent Application No. 0012463.
No., No. 0040867, No. 0162613, No. 01
No. 65799, No. 0178531, No. n791g4 and No. 0180051 or U.S. Patent No. 4.174
, No. 332.

The main properties of pigment paste resins are high pigment binding strength, favorable viscosity and solubility. Examples of such pigment paste resins are U.S. Pat. No. 377,270;
No. 378,963, German Patent Publication No. 22525
No. 36, No. 2531960, No. 2634211, No. 2634229, European Patent Application No. 0028402,
No. 0049369, No. 0076955, No. 0135
No. 651 or US Pat. No. 4.035.275.

Additives mixed into the pigment component of the present invention include catalysts such as zinc octoate, lead octoate, cobalt octoate or dibutyltin dilaurate, and Texanol (2°2.4-trimethylpentane-1). , 3-diol defoamers, adhesion promoters, and the like.

Common electrodeposition bath materials for cationic electrodeposition coatings contain a main binder and a pigment paste resin in a ratio between 4:1 and 2:1, with a pigment-binder ratio between 0.1:1 and 2:1. The ratio is 0.7:1.

The pigment component of the present invention contains a resin component having a ratio of 70% to 30% by weight of the fat for pigment paste and 30% to 70% by weight of the main binder for coating material addition. Preferred proportions of the resin component are from 70% to 50% by weight to 30% to 50% by weight.

The pigment paste resin component combination of the present invention includes pigments commonly used in electrodeposition coatings in pigment binder ratios of 8:1 to 1:1 (pure black paint) or 12:1 to 5:1 (pure black paint). Contains standard base coats and single coats). The types of pigments are known to those skilled in the art;
You can find out about it in related literature.

To produce the pigment paste (tympanic membrane component), the mixed and dispersed aggregates commonly used in the paint industry are used. The formulation and preparation of electrodeposition paints are known to those skilled in the art and do not require detailed explanation.

The following examples are intended to illustrate the invention:
It is not intended to limit the scope of the invention.

All parts or percentages are by weight unless otherwise specified.

The following strategy was used in the examples.

BtJC,L Ethylene glycol monobutyl ether CE 1. Industrial glycidyl ether mixture of l-dimethyl-(C7Cs)carboxylic acids DGME Diethylene glycol dimethyl ether DEAPA N,N-diethylaminopropylamine DMAPA 'N,N-dimethylaminopropylamine MOLA Monoethanolamine PE 91 91% roseformaldehyde PSA
Phthalic anhydride TDI) lylene diisocyanate (80/T
HMDI ) Limethylhexamethylene diisocyanate DOLΔ Jetanolamine The following products are those used as single components in the examples.

(A) Resin for pigment paste (A1) In a suitable reaction vessel, 74 parts of PSA and 162 parts of oxazolidine derivative were heated to an acid value of 120 at 75 to 80°C.
React until mgKDH/g. The oxazolidine derivative contains 24 parts of MOLA of hydroxyamine;
100 parts CE and 33 parts PF91 to 60 to 1
It is obtained by a ring-forming reaction at 20° C. with azeotropic removal of about 8 parts of water of reaction.

Add 320% polypropylene glycol-based epoxy resin (approx. 320% epoxy resin) to the above reaction mixture.
This is esterified at 120° C. until the acid value becomes less than 3 mg KOH/g. After cooling to 70°C, DEA
Add 52 parts of PA and maintain the temperature until the epoxy value is zero.

After adding 13 parts of PF91, special benzine (boiling point 80-120°C) is added as an azeotropic agent to azeotropically remove 8 parts of reaction water. Subsequently, 125 parts of oxazolidine prepared as described above was mixed and cooled to 30 to 35°C. Therefore, 84 parts of THMD I was added little by little to 50 parts.
Continue the reaction at °C until all inanate groups are consumed.

After removal of the entrainer, the reaction product is dissolved in 200 parts of BUGL. The test yields the following values:

Viscosity: 21.000 mPa-s/
Oxazolidine equivalent at 25°C: 624 (calculated value) Amine value: 116 mgKDH/g Aliphatic component: 59% Molecular weight (calculated value): 1650 Solubility (1): 15 m of formic acid per 100 g of resin solid content! ,! of (1) Amount of acid required to form a stable aqueous dispersion (A2) In a suitable reaction vessel, add a polypropylene glycol-based epoxy resin (epoxy equivalent of approximately 320
) 320 parts, beef tallow amine 134 parts and DEAPA5
2 parts at 75-80° C. until the epoxy value is zero. After adding 30 parts of PF91, 19 parts of reaction water are azeotropically removed using special benzene (boiling point 80-120 DEG C.). The entrainer is removed by vacuum distillation. The resin shows the following values.

Viscosity: 1500 mPa-5/25℃ Oxazolidine equivalent: 574 (calculated value) Amine value: 141 mgKOH/g Aliphatic component: 86% Molecular weight (calculated value): 1034 Solubility (see above): Dissolved without adding acid (A3) In a suitable reaction vessel, epoxidized polybutene oil (molecular weight approximately 1,400, epoxy equivalent 440) was mixed with 92 parts of DMAPA (0.9 mol) and 0.5 parts of 2.
The reaction is carried out in the presence of 6-tert-butyl-4-methylphenol (inhibitor) at 160 DEG to 200 DEG C. until all epoxy groups are consumed. After cooling to 80℃, 30
of PF91 (0.9 mol) and special benzine (
This temperature is maintained until 18 parts of the reaction water have been removed azeotropically, with point A (80-120 DEG C.). After removing the entrainer in vacuo, the reaction mixture is dissolved in 59 parts of BUGL. The resin shows the following values.

Viscosity: 2600 mPa-5/25℃
Oxazolidine equivalent: 604 (calculated value) Amine value: 185 mgKOH/g Aliphatic component: 80% Molecular weight (calculated value): 1632 Solubility (see above): 2 formic acid per 100 g of resin solid content
5mMol (B) Main binder (B1) In a suitable reaction vessel, 228 parts of bisphenol A (1 mol) and 260 parts of DEAPA (2 mol) are heated to 75°C in the presence of 131 parts of toluene, and then 66 parts of PF91 (2
mol> is added.

The temperature is slowly increased until azeotropic distillation continues. After removing 42 parts of the reaction water, the toluene is distilled off under vacuum and 608 parts (2 mol) of 152 parts of the reaction product are added within 45 minutes.

After the NC0 value became almost zero, 1400 parts of this solution, 190 parts of bisphenol A-based epoxy resin (epoxy equivalent 190) and 250 parts of CE (1 mol) were added.
and a solution of 389 parts of DGME to give a solution of 95 to 10
The reaction is carried out at 0°C until the epoxy value becomes zero.

75 parts (solid content) of the above solution and 25 parts (solid content) of the following polyhydroxy compound were thoroughly mixed, and 35 mMo
1 of formic acid is added. A 40% dispersion is then made with deionized water.

The polyhydroxy compound used above becomes water-soluble by protonation and exhibits a ○H equivalent of about 145. This compound contains 1 mole of bisphenol A-based epoxy resin (epoxy equivalent: 475), 1! :2 moles of DOLA to 7
4 gl in 0% methoxypropanol in a known manner.

(B2) Reaction 5 with stirrer, thermometer and reflux condenser
Then, 1000 parts of bisphenol A-based epoxy resin (epoxy equivalent 500) was dissolved in 492 parts of ethylene glycol acetate at 60 to 70°C.
．． Add 2 parts of hydroquinone and 144 parts of acrylic acid and raise the temperature to 100-110°C. At this temperature, the reaction is carried out until the acid value becomes 5 mgKDH/g or less (DBZ-1,75). Then this reaction product was given 60
Add a 70% solution of basic monoisocyanate at 70°C to 70°C and react until the NC value becomes almost zero (D
BZ=1.25. BNZ=1.1>. Solid content 100
After adding 60mMoim of formic acid to g, a 35% dispersion is prepared with deionized water.

Basic (bα5ic) monoisocyanate is TD11
It is the reaction product of 1 mole of DOLA and 70% solution in methyl isobutyl ketone.

DBZ (Number of double bonds) Aimed at the number of terminal ethylenic double bonds per bimolecule ff11000 units.

BNZ (Number of bases) Corresponds to the number of basic N groups per 1000 units of bimolecular collapse.

(B3) 700 parts of commercially available polybutadiene oil,
100 parts of maleic anhydride at 200°C in the presence of 0.5 part of diphenyl-P-phenylenediamine (inhibitor).
The maleic anhydride is reacted in a known manner until complete binding. After cooling to 100°C, 130 parts of 2-ethylhexanol are added and esterification is carried out at 120°C until the theoretical acid value of the half ester is reached.

110 parts of the obtained reaction product (corresponding to about 0.12 CODH groups) and 212 parts of a 80% DGME solution of a bisphenol-diepoxy resin (epoxy equivalent: 190) were mixed into 1
The reaction is carried out at 20°C until the acid value becomes almost zero. DGME
108 parts of DEA, PA591 (0.45 mol) and 59 parts (0.45 mol) of 2-ethylhexylamine are added and the reaction mixture is reacted at 65-70 DEG C. until the epoxy number is approximately zero. After reaching this value, 11
4 parts of bisphenol A (0.5 mol) and 50 parts of PF
91 (1.5 mol) and the reaction is continued at 60° C. until the free formaldehyde content is between 0.5 and 1%. 40 m/100 g of solids in the reaction mixture! Jo
1 of formic acid is added and diluted to 45% solids with deionized water.

The polybutadiene oil used was a liquid containing about 75% 1°4-cis isomer, about 24% 1,4-1-lance isomer, and about 1% vinyl double bond.

Molecular weight is approximately 1500±15, iodine value is approximately 450g/1
000'g.

(C) Additive component (C1) Dibutyltin dilaurate: 1 in terms of metal content
8% solvent-free type (C2) Dibutyltin oxide dimetallic content 48%
Solid world (C3) Lead octoate: 90 parts mixed hydrocarbon solution (metal content 31%) (C4) Cobalt octoate: 80% white spirit solution (metal content 11%) (C5) Acetylene alcohol Base AI agent: Used as a 50% solution of ethylene glycol monoethyl ether (D) Pigment composition Main binder (B component) dissolved in an organic solvent and additive component (C component) at room temperature or if necessary. Mix thoroughly for approximately 30 minutes at higher temperature (up to 80° C.). The pigment paste resin (component A) and other additives, such as defoamers or other coating aids, if necessary, are then mixed for an additional 30 minutes. Add neutralizing acid with further stirring, followed by deionized water to achieve the desired solids content and viscosity to form a water-free clear lacquer. The pigment is added and the mixture is mixed and dispersed in a suitable mixing and dispersing device, preferably a pearl mill or sand mill.

The pigment paste composition is summarized in Table 1. All parts shown indicate solid content.

(1) Calculated as metal (2) mMo1 of acid per 100 g of solid content AS = formic acid, ES = acetic acid (3) Solid content of pigment paste after dilution with deionized water (%)
) (4) Pigment/binder ratio Pigment pastes were also prepared by the alternative method described herein, and the test results confirmed that there was no clear difference.

Table 2 shows the pigment paste compositions of Comparative Examples 1 to 3. In Comparative Examples 1 and 2, the additives are added to the aqueous pigmented paint bath in the amounts (parts) listed in (C) diluted with the same amount of ethylene glycol monobutyl ether. Comparative example 3 is
Insoluble dibutyltin oxide, which is a solid product, is mixed and dispersed with the pigment in a conventional manner.

Pigment paste according to the invention and according to the prior art Table 3 lists the compositions of electrocoating paint baths obtained by mixing pigment paste components and clear lacquer components (main binder).

Furthermore, Table 3 lists the test results regarding paintability and stability as well as the performance and durability of the coating film.

Test method Sieve residue: 1f diluted paint liquid! weighed bar
o7 (Perlon) sieve (mesh 28μm)
Pour into and let it pass. The sieves are rinsed with deionized water and weighed after drying (1 hour at 110° C.). Results are expressed in mg of sieve residue.

Horizontal coating Bend a zinc diphosphate steel plate (approximately 1010 x 20) at a right angle in the center.Hang one side of the bent steel plate horizontally so that it is 15 cm deep from the surface of the paint bath.Stop stirring the paint bath and leave it for 4 minutes. Paint.

After painting, the steel plate remains in the paint bath for an additional 2 minutes. Then remove the tfm IrR from the paint bath, rinse with water for an additional 2 minutes, and bake. The steel plate is visually evaluated for leveling, gloss and deposition phenomena.

Stirring stability: The paint bath is stirred continuously at 25±2° C. in an open container. Electrodeposition is carried out after the time shown in Table 3,
It is shown that there is no obvious change in the electrodeposited coating when compared with the coating that was electrodeposited in a fresh paint bath. (Performed after homogenizing the paint bath for 24 hours) The abbreviations in Table 3 have the following meanings.

1.0.　　　　　　There is no abnormality in the coating film, and there are no signs of deposits.

LM Slight loss of luster.

M: No gloss, no leveling problem.

S: There are obvious signs of sedimentation.

n, i, O, paint film cannot be used.

Salt spray test: According to ASTM-B 117-64.

Electrodeposit to a film thickness of 22±2 μm on a zinc phosphate steel plate and bake under the conditions listed in Table 3.

Claims (1)

[Scope of Claims] 1. In a method for producing a pigment paste for water-dilutable paints, particularly for a two-component replenishment method in electrodeposition coating using a catalytically cured paint, the resin (A) for pigment paste for paints contains the required amount. Before or after mixing and dispersing all or part of the catalyst and/or other additives (C) and a part of the main binder for paint (B) with the pigment (D), or salt formation. A method for producing a pigment paste, which comprises uniformly mixing and dispersing before or after neutralizing some or all of the groups. 2. (a) 70% by weight of pigment paste-forming resin to 3
0% by weight, preferably 70% to 50% by weight, and (b) the main binder for paint (B), in which all or part of the paint additive (C) necessary for the paint system is uniformly mixed.
0% to 70% by weight, preferably 30% to 50% by weight, and after neutralizing all or part of the salt-forming groups, the pigment (D) is mixed in a subsequent mixing and dispersing step using a mixing and dispersing device. The manufacturing method according to claim 1, characterized in that after addition, the method is diluted with water to obtain an optimal viscosity. 3. The above components are arranged in the following order: (A+N)+(B+C)+W+D, or (A+C)+N+B+W+D, or (A+B)+N+C+W+D (where A to D are the components listed in claim 1). 2. The manufacturing method according to claim 1, characterized in that mixing and dispersing is carried out using the following methods: (N represents neutralization, W represents addition of water). 4. According to any one of claims 1 to 3, the additive (C) other than the above-mentioned additives is a water-incompatible solvent and/or a coating aid. manufacturing method. 5. A pigment paste produced by the method according to any one of claims 1 to 4, characterized in that the pigment binder ratio is 1:1 to 12:1. 6. Use of a pigment paste produced by the method according to claims 1 to 4 in an electrodeposition paint. 7. Pigment paste produced by the method described in claims 1 to 4 used as a pigment paste for a two-component replenishment method for electrodeposition coating, for use in a two-component replenishment method for electrodeposition coating. use.