Pigment Preparations

A mixture of 45 g of an oxidised carbon black pigment and 55 g of a polyether-urethane resin with carbodiimide groups is kneaded in a dispersion kneader, equipped with heating, of the Werner + Pfleiderer system, for 2 to 3 hours at temperatures of 90.degree. to 140.degree. C. The resin is prepared according to the following process:

7.6 g of 1,2-propylene glycol are added to 222 g of 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethyl-cyclohexane and the mixture is warmed to 240.degree. C., in the course of which 5 liters of CO.sub.2 (25.degree. C.) are eliminated after approx. 40 minutes. 183 g of this reaction product which according to the IR spectrum contains both isocyanate groups and carbodiimide groups, are introduced, starting at 130.degree. C., into a mixture consisting of (1) 227 g of a linear polyether of average molecular weight 2,000, prepared from propylene glycol and propylene oxide and containing 1.8% of hydroxyl groups, and (2) 127 g of 2,2-bis-(4-hydroxy-cyclohexyl)-propane, over the course of 10 minutes, during which the temperature rises to 170.degree. C. After heating for 2 hours to 170.degree.14 180.degree. C., a resin which is soluble in ethyl alcohol, acetone, ethyl acetate or glycol monoethyl-ether acetate and has a melting range of 90.degree.-110.degree. C. is left.

The kneading process with resin and carbon black pigment is carried out by producing a viscous kneadable mass, at the start of the kneading process by heating the kneader and then completing the dispersion by kneading for 2 to 3 hours in the stated temperature range. In order to be able to maintain this kneading temperature it can be necessary to cool the kneader again, after it has been heated up, because of the heat generated by the kneading. A pigment preparation is obtained, which is cooled to room temperature and then ground to a coarse powder.

This pigment concentrate is very suitable for use in colouring polyisocyanate reaction lacquers, but because of the good compatibility of the polyether-urethane resin can also be used for colouring nitrocellulose lacquers or chlorinated rubber lacquers. Thus, for example, 2.4 g of the pigment preparation, which has been ground to a coarse powder, are distributed in 70 g of a 28.6% strength solution of a branched polyester containing hydroxyl groups (hydroxyl content approx. 7.6%) in a solvent mixture of ethyl acetate, butyl acetate, glycol monoethyl-ether acetate and toluene, in a glass flask over the coarse of one hour on a shaking stand, without great expenditure of energy. After mixing in 30 g of a 75% strength solution of a polyfunctional aromatic isocyanate having an NCO content of 13%, a black reactive lacquer is obtained, which is very glossy after drying. The lacquer further diluted 2:1 with glycol monomethyl-ether acetate, when poured onto glass, allowed to run off vertically and dried, gives a thin, very glossy lacquer film with a completely uniform brownish colouration of high transparency.

If a high speed stirrer is used, 2 g of the pigment concentrate can be dissolved, without leaving specks, in 100 g of a nitrocellulose-alkyd resin lacquer of 25% solids content, in 10 to 15 minutes.

40 g of a copper phthalocyanine in the .beta.-modification are dispersed in 60 g of the resin from Example 1 under the same kneading conditions, but in the temperature range of 90.degree. to 120.degree. C., and after cooling the product is ground to a coarse powder. A conventional stoving lacquer, consisting of 62.5 parts by weight of a non-drying alkyd resin containing 24% of oil and 43% of phthalic anhydride, 60% strength in xylene, 20.0 parts by weight of a butanol-etherified melamine resin, 55% strength in butanol, 7.5 parts by weight of xylene, 8.0 parts by weight of ethylene glycol monethyl ether and 2.0 parts by weight of glycollic acid butyl ester is pigmented as follows with the pigment concentrate:

1.5 g of the ground pigment preparation are dispersed in 100 g of the lacquer over the course of 15 minutes, by means of a high speed stirrer. The lacquer film produced from the coloured lacquer on an aluminium foil, with the aid of a 100 .mu.m doctor blade, shows high transparency and high gloss after stoving for 30 minutes.

40 g of an oxidised carbon black pigment (specific surface area by the BET method: 180 m.sup.2 /g) are dispersed in 200 g of a 30% strength resin solution of the resin described in Example 1 in glycol monoethyl-ether acetate, over the course of 8 hours in a vibration mill, using 700 g of porcelain balls of diameters from 8 to 10 mm. The pourable pigment paste thus obtained is incorporated, with stirring, into the lacquers mentioned in Example 1 and 2, taking into account the lower carbon black pigment content of the pigment paste.

A very readily pourable pigment paste without structural viscosity is obtained by grinding 25 g of an oxidised carbon black pigment and 75 g of a 25% strength solution of the resin from Example 1 in benzyl alcohol on a cone mill. This highly concentrated pigment paste, which is very economical in use, can be employed very successfully for marking purposes.

20% of the yellow pigment of the formula ##STR1## 16% of a polyester-urethane resin with carbodiimide groups and 64% of glycol monoethyl-ether acetate are stirred in a high speed stirrer and then ground in a high speed agitator mill which consists of a cylindrical grinding vessel and has a shaft, provided with plane circular discs, as the mixing device. The mill contains glass beads of 0.3-0.4 mm diameter as the grinding bodies. The circumferential speed of the discs is approx. 10 m/sec.

The polyester-urethane resin can be obtained as follows: a reaction product with 22.7% of carbodiimide groups, relative to the free NCO groups, is first prepared, by heat treatment, from 1-isocyanato-3-isocyanato-methyl-3,5,5,-trimethylcyclohexane and ethylene glycol. 100 parts by weight of this pre-adduct containing NCO are reacted with a mixture of 20 g of ethylene glycol and 132 g of a polyester, containing 1.6% of hydroxyl groups, from 5 mols of adipic acid, 3.5 mols of diethylene glycol and 2.3 mols of 2,2-bis-(4-hydroxy-cyclohexyl)-propane.

The resin containing urethane groups and carbodiimide groups is soluble in acetone, ethyl acetate and glycol monomethyl-ether acetate. The viscosity of a 40% strength solution in glycol monomethyl-ether acetate in the Hoppler falling ball viscometer is 2 poise. The resin contains 1.3% of hydroxyl groups.

A pigment dispersion is obtained in the same way as in Example 4 when using, instead of the yellow pigment, one of the following pigments:

a. a tetracholorothioindigo pigment (Pigment Red 88)

b. a chlorinated copper phthalocyanine pigment (Colour Index II. No. 74,620).

Pigment dispersions of the following composition are prepared in the same way as in Example 4.

a. 12% of Pigment Yellow 83, 17% of polyester-urethane from Example 4 and 71% of glycol monethyl-ether acetate.

b. 18% of carbon black (surface area by the BET method: 180 m.sup.2 /g, pH value of the aqueous carbon black suspension approx. 3) 27% of polyester-urethane from Example 4 and 55% of glycol monoethyl-ether acetate.

c. 60.0% of rutile titanium dioxide, 15.0% of polyester-urethane from Example 4, 0.5% of highly disperse silica and 24.5% of glycol monoethyl-ether acetate.

d. 50.00% of a finely divided synthetic yellow iron oxide ground in a jet mill, 16.70% of polyester-urethane from Example 4, 32.64% of glycol monoethyl-ether acetate and 0.66% of a dispersion consisting of 15 parts by weight of a special magnesium montmorillonite treated with organic ammonium bases, 79 parts by weight of xylene and 6 parts by weight of glycol monoethyl-ether acetate.

Instead of being ground with glass beads of 0.3-0.4 mm diameter, the pigment dispersions (c) and (d) are ground with glass beads of 0.6-0.9 mm diameter.

A resin product prepared by the following process is used instead of the polyester-urethane employed in Examples 4, 5 and 6:

3.1 g of 1,2-propylene glycol and 89 g of 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylcyclohexane are added to 120 g of a polyester, containing 1.7% of hydroxyl groups, from 5 mols of adipic acid, 3.5 mols of diethylene glycol and 2.3 mols of 2,2-bis-(4-hydroxy-cyclohexyl)-propane, at 125.degree. to 135.degree. C. and the mixture is then heated to 240.degree. C. for 45 minutes, during which 2 liters of CO.sub.2 (23.degree. C.) are eliminated. After cooling to 160.degree. C., sufficient glycol monoethyl-ether acetate is added that after addition of 30 g of 2,2-dimethyl-1,3-propane-diol and subsequent reaction for 1 hour at 150.degree. C., a 50% strength resin solution is obtained.

a. 4 g of the paste from Example 5 or 7, containing 18% of carbon black, are introduced, with stirring, into a solution consisting of 30 g of a crosslinkable polyester-polyurethane with terminal OH groups and 70 g of ethyl acetate. After stirring from about 2 minutes, a homogeneously coloured polyurethane solution is obtained, which after addition of a polyisocyanate of 13% NCO content and of a heavy metal salt is suitable as an accelerator for coating textiles by the reverse coating or direct coating process.

b. 10 g of the pastes from Example 6 or 7 are introduced, with stirring, into 100 g of the same 30% strength solution of a polyester-urethane in ethyl acetate. Even after brief stirring, the polyester-urethane solution acquires a homogeneous colouration and after addition of polyisocyanate and accelerator this solution gives speck-free coatings by the direct coating or reverse coating process.

c. 4 g of the 18% strength carbon black paste from Example 5 or 7, or 10 g of the pastes from Example 6 or 7, are introduced, with stirring, into a solution which consists of 25 g of a polyester-urethane, 45 ml of dimethylformamide and 30 ml of methyl ethyl ketone. In each case, homogeneously coloured polyurethane solutions are obtained after brief subsequent stirring. These pastes are miscible with one another and give uniform, very glossy coatings on textiles by the customary coating process.

The one-component polyurethane used is prepared from a polyester of adipic acid and hexanediol/neophentyl glycol of average molecular weight 500-3,000 and diphenylmethane-4,4'-diisocyanate, with subsequent reaction with butanediol.

d. 9.5 g of the 60% strength titanium dioxide paste from Example 6 or 7 and 0.5 g of the 50% strength yellow iron oxide paste from Example 6 or 7 are introduced, whilst stirring, into 100 g of a 25% strength solution of a non-yellowing polyester-urethane in equal parts of toluene and isopropanol, prepared from a polyester of molecular weight 1,000 with hexanediol, neopentyl glycol and adipic acid as well as isophorone-diiso-cyanate and isophoronediamine. After brief stirring, a uniformly coloured polyurethane solution is obtained, the colour shade of which is stable even after prolonged storage, and which gives very glossy textile coatings by customary processes.

10 g of the black paste from Example 7, containing 18% of carbon black, are introduced, with stirring, into 100 g of a 50% strength solution of a polyacrylate containing hydroxyl groups (4.2% hydroxyl group content, calculated relative to solid binder) in equal parts of glycol monoethyl-ether acetate and xylene, catalysed with a tertiary amine. Thereafter, 30 g of an aliphatic polyisocyanate containing 16% of NCO are mixed in. The lacquer applied to a contrast paper by means of a 100 .mu.m doctor blade dries to give a black, very glossy film. A cast film, in glass, of the reactive lacquer diluted 1:1 with a solvent mixture of equal parts of glycol monoethyl-ether acetate, butyl acetate and xylene, gives, after drying, a very glossy, brownish lacquer coating of high transparency, without signs of flocculation.

6 g of a finely divided synthetic red iron oxide and 5 g of a 40% strength solution of a polyester-urethane, in which carbodiimide groups have been produced by catalysis with phospholine oxide, in glycol monoethyl-ether acetate, are added to 25 g of a 40% strength solution of a polyester containing hydroxyl groups, of approx. 8% OH content, in glycol monomethyl-ether acetate, in a 125 cm.sup.3 polyethylene vessel containing 100 g of glass beads of 5 mm diameter. This charge is dispersed, in the closed vessel, for 30 minutes on a paint shaker. A charge which merely contains the same amount of the solution of the polyester containing hydroxyl groups and of the red iron oxide and which is dispersed with the same amount of glass beads for 30 minutes on the paint shaker. is run in parallel. The vessels are opened after standing 1 hour. The grinding charge with the added carbodiimide runs smoothly down the walls of the vessel whilst the charge without this addition shows pronounced flocculation on running down the walls of the vessel. These great differences with regard to flocculation are also recognisable in the lacquer films of the two-component polyurethane lacquers produced from these charges. After adding, in each case, 12 g of a 75% strength solution of an aliphatic polyisocyanate with an NCO content of approx. 16%, both batches are spread alongside one another on aluminium foil, with the aid of a doctor blade of 100 .mu.m gap width. After drying the lacquer films, the charge with the additive shows a distinctly more yellowish shade. On rubbing out the spread lacquer films (rub-out test) the colour shade of this batch does not change, whilst that of the parallel experiment assumes a distinctly more yellowish shade, corresponding to that of the batch with the additive, in the areas which have subsequently been rubbed with the finger tip.

The polyester-urethane resin employed here can be prepared as follows:

0.22 g of phospholine oxide is added to 222 g of 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylcyclohexane and the mixture is heated to 125.degree. C. until 5 liters of CO.sub.2 (at 23.degree. C.) have been eliminated. At this stage, 22.7% of the NCO groups have been converted into carbodiimide groups.

194 g of the above product are reacted with a mixture of 40 g of ethylene glycol, 7 g of 1,2-propylene glycol and 280 g of a polyester, containing 1.6% of hydroxyl groups, from 5 mols of adipic acid, 3.5 mols of diethylene glycol and 2.3 mols of 2,2-bis-(4-hydroxy-cyclohexyl)-propane, at 125.degree. to 170.degree. C. The reaction product contains 1.5% of hydroxyl groups.

32 g of a tetrachlorothioindigo pigment (Pigment Red 88) are dispersed in 168 g of a 30% strength solution of a polyester-urethane, possessing carbodiimide groups, in glycol monoethyl-ether acetate, in a 1 liter laboratory vibratory mill, using 700 g of porcelain balls of diameter 0.8 to 1 cm, for 6 hours. A very readily pourable pigment concentrate results, which can be used to colour, without signs of flocculation, a two-component polyurethane lacquer; for this purpose, 25 g of the above pigment concentrate are added to 70 g of a 28.6% strength solution of branched polyesters containing hydroxyl groups (hydroxyl content approx. 7.6%) in a solvent mixture of ethyl acetate, butyl acetate, glycol monoethyl-ether acetate and toluene. After mixing, 30 g of a 75% strength solution of a polyfunctional aromatic isocyanate with an NCO content of approx. 13% are stirred in. This two-component lacquer, pigmented red-violet, shows a high gloss when applied to aliminium foil; a lacquer coating applied to glass by casting shown high transparency with excellent pigment distribution.

The polyester-urethane resin used here can be obtained as follows:

886 g of 1-isocyanato-3-isocyanato-methyl-3,3,5-trimethylcyclohexane are reacted with 84 g of cyclohexanol and the mixture is heated to 240.degree. until 20 liters of CO.sub.2 (20.degree. C.) have been eliminated. After cooling, the reaction product is introduced into a mixture of 300 g of 2,2-dimethyl-1,3-propanediol and 1,200 g of a polyester, containing 1.7% hydroxyl groups, from 5 mols of adipic acid, 3.5 mols of diethylene glycol and 2.3 mols of 2,2-bis-(4-hydroxy-cyclohexyl)-propane, and the solids content of the mixture is adjusted to 50% with glycol monoethyl-ether acetate. The IR spectrum of the end product shows the band at 4.75 .mu.m which is characteristic of the carbodiimide group.

12 g of a synthetic transparent yellow iron oxide with an average particle size of 0.02 .mu.m are dispersed, over the course of 8 hours, in 24 g of a 50% strength solution of a modified polycaprolactone in glycol monoethyl-ether acetate and 112 g of a 50% strength solution of a polyester (OH content approx. 8%) in glycol monomethyl-ether acetate, in a 1/2 liter vibratory ball mill with 350 g of porcelain balls of 5 mm diameter as the grinding bodies. Thereafter, 69.5 g of a 75% strength solution of an aliphatic polyisocyanate with 16.5% NCO are added to the ground material. The lacquer, applied by means of a doctor blade with 100 .mu.m gap width onto black-and-white contrast paper dries to give a very glossy film coloured transparent golden yellow.

The modified polycaprolactone which contains carbodiimide groups is prepared as follows:

199.35 g of 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylcyclohexane are added to a mixture of 70.65 g of a polycaprolactone containing hydroxyl groups (hydroxyl content about 6.5%) obtained by using diethylene glycol as the starter, and 9.4 g of cyclohexanol, and the mixture is kept at a temperature of 240.degree. C. until 4.5 liters of CO.sub.2 (25.degree. C.) are eliminated. After cooling, 339.4 g of glycol monoethyl-ether acetate and 68.2 g of 2,2-dimethyl-1,3,-propanediol are added successively. The reaction is concluded within 1 hour at 150.degree. C. The viscosity of the 50% strength resin solution in glycol monoethyl-ether acetate is 306 centipoise (measured in a Hoppler viscometer at 25.degree. C.).

0.8 of a surface-oxidised carbon black pigment (specific surface area, by the BET method: 180 m.sup.2 /g) is dispersed in 25 g of a 40% strength solution of a polyester containing hydroxyl groups, with an OH content of approx. 8%, in glycol monomethyl-ether acetate for 30 minutes in a 125 cm.sup.3 polyethylene vessel, using 100 g of glass beads of diameter 5 mm, on a paint shaker.

An identical charge except for the addition of 4 g of a 40% strength solution of a carbodiimide-containing polyurethane in toluene, is dispersed in parallel. Even after brief standing (about 30 minutes) it can be seen that only the second charge remains homogeneous in colour, whilst the first shows distinct flocculation when running down the side of the vessel. The carbodiimide-containing polyurethane resin without ester groups of ether groups can be obtained by the following process:

7.6 g of 1,2-propylene glycol are added to 220 g of 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylcyclohexane. After heating to 240.degree.-250.degree. C., 15 liters of CO.sub.2 (25.degree. C.) are eliminated over the course of 1.2 hours. In addition to urethane and NCO, the IR spectrum only shows a very strong carbodiimide band. After cooling, and adding 35 g of 2-ethylhexanediol-1,3, a carbodiimide resin which is free of isocyanate groups and gives a clear solution in toluene is produced.

157 g of a polyester from adipic acid and diethylene glycol, which has a linear structure and contains 1.3% of hydroxyl groups, are reacted with a mixture of 3 g of 1,2-propylene glycol and 89 g of 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylcyclohexane and the mixture is then heated to 240.degree. C. for 1 hour, during which 2 liters of CO.sub.2 (20.degree. C.) are eliminated. A very viscous resin containing carbodiimide groups is obtained, which is soluble in phthalate plasticisers or phosphate plasticisers.

20 g of a surface-oxidised carbon black pigment are dispersed in 80 g of a 20% strength solution of this resin in diphenyl-2-ethylhexyl phosphate in a cone mill. A very readily pourable pigment paste is obtained, by means of which a very deep colour is produced in polyester-urethane foams by stirring 10 g of the black pigment paste into a mixture of 200 g of a slightly branched polyester from adipic acid, diethylene glycol and trimethylolpropane, having an OH number of 50, and 73.2 g of toluylenediisocyanate, and causing the mixture to form by the customary addition of water and auxiliaries.

100 g of cyclohexanol are first introduced over the course of 20 minutes, whilst stirring, into 174 g of toluylenediisocyanate, consisting of 80% of toluylene-2,4-diisocyanate and 20% of toluylene-2,6-diisocyanate, starting at 125.degree. C.; after completion of the first reaction 73 g of 2-ethyl-1,3-hexanediol are introduced at 140.degree. C., whereupon the temperature rises to 165.degree. C. After 30 minutes, 0.5% of phospholine oxide is added and the temperature is raised to 190.degree. C. In the course thereof, 2 liters of CO.sub.2 (25.degree. C.) are eliminated within 50 minutes. The resin shows the carbodiimide band in the infrared spectrum at 4.75 .mu.m.

20% of a lamp black having a BET surface area of 110 m.sup.2 /g (pH value of the aqueous suspension =5) can be dispersed by means of a corundum disc mill in a 10% strength solution of the resin in a branched polyether having an average molecular weight of 4,800, so as to give a pourable carbon black paste. This paste is very suitable for foaming in moulds, using diphenylmethane-4,4'-diisocyanate as the polyisocyanate component. However, the paste can also be used to colour solvent-containing one-component lacquers with reactive NCO groups, shortly before the lacquers are used.

20 g of a surface-oxidised carbon black pigment having a BET surface area of 180 m.sup.2 /g are dispersed in 80 g of a 30% strength solution of the resin from Example 15, containing carbodiimide groups, in diphenyl cresyl phosphate over the course of 30 minutes on a paint shaker using glass beads of 3 mm diameter. A carbon black paste which is very readily pourable and is distinguished by high resistance to flocculation is obtained. The paste is particularly suitable for colouring ester-based polyurethane foams.

75 g of cyclohexanol are first introduced over the course of 20 minutes, whilst stirring, into 174 g of toluylene-diisocyanate, consisting of 80% of toluylene-2,4-diisocyanate and 20% of toluylene-2,6-diisocyanate, starting at 125.degree. C.; after completion of the first reaction 100 g of 2-ethyl-1,3-hexanediol are introduced at 140.degree. C., whereupon the temperature rises to 165.degree. C. After 30 minutes, 0.5% of phospholine oxide is added and the temperature is raised to 190.degree. C. In the course thereof, 2 liters of CO.sub.2 (25.degree. C.) are eliminated within 50 minutes. The resin shows the carbodiimide band in the infrared spectrum at 4.75 um. The resin contains 2.4% hydroxyl groups and has a viscosity, measured in the Hoppler falling ball viscosimeter at 25.degree. C. in a 35% strength solution in a polyether with a molecular weight of 4800 of 536 poise.

15 g of a lamp black having a BET surface area of 110 m.sup.2 /g (pH value of the aqueous suspension = 5) is dispersed by means of a corundum disc mill in 85 g of a 1.2% strength solution of the resin in a branched polyether having an average molecular weight of 4,800, prepared from trimethylolpropane with 87% propyleneoxide and 13% ethyleneoxide, so as to give a pourable carbon black paste. This paste is very suitable for foaming in moulds, using diphenylmethane-4,4'-diisocyanate as the polyisocyanate component. However, the paste can also be used to colour solvent-containing one-component lacquers with reactive NCO groups, shortly before the lacquers are used.