Patent ID: 8461229

Claim:
A method of producing a colored polyamide engineering plastic comprising a) preparing a pigment composition by mixing an organic pigment and a prepolymer in a liquid medium; and b) coloring a polyamide engineer plastic by processing together the pigment composition from a) and the polyamide engineering plastic at a temperature of about 220 to 350 ° C.; wherein the pigment composition comprises solid particles, which particles comprise from 20 to 75% by weight of an organic pigment and from 80 to 25% by weight of a crosslinked polymer, each based on the total weight of the solid particles, wherein the prepolymer has average molecular weight M w from 2000 to 200000, which prepolymer comprises (a) repeating blocks of formula and (b1) hydroxy, epoxy or primary or secondary amino groups or (b2) unsaturated bonds, wherein R 1 is H, C 1 -C 4 alkyl, C 2 -C 4 alkenyl or COOR 5 , R 2 and R 3 are independently from one another H, OR 6 , NHR 6 , C 1 -C 4 alkyl or C 2 -C 4 alkenyl, R 4 , R 5 and R 6 are independently from one another H, unsubstituted C 1 -C 6 alkyl or C 2 -C 6 alkenyl, or C 2 -C 6 alkyl or C 2 -C 6 alkenyl each substituted by one or more hydroxy and/or epoxy groups, and n is a number from 2 to 2000; wherein the organic pigment is selected from the group consisting of pyrrolo[3,4-c]pyrroles of the formula wherein R 7 and R 8 are each independently of the other a group of formula R 9 and R 10 are each independently of the other hydrogen, halogen, C 1 -C 24 alkyl, trifluoromethyl, C 5 -C 6 cycloalkyl, C 1 -C 18 alkoxy, C 1 -C 18 alkylthio, C 1 -C 18 alkylamino, cyano, carbamoyl, nitro, phenyl, C═N—C 1 -C 24 alkyl imidazolyl, pyrazolyl, triazolyl, piperazinyl, pyrrolyl, oxazolyl, benzoxazolyl, benzothiazolyl, benzimidazolyl, morpholinyl, piperidinyl or pyrrolidinyl, preferably hydrogen, halogen, cyano, carbamoyl, nitro, trifluoromethyl, phenyl, C 1 -C 6 alkyl, C 1 -C 6 alkylthio or C 1 -C 6 alkylamino; R 11 and R 12 are each independently of the other hydrogen, halogen or C 1 -C 6 alkyl; R 13 is —CH 2 —, —CH(CH 3 )—, —C(CH 3 ) 2 —, —CH═N—, —N═N—, —O —, —S—, —SO—, —SO 2 —NH or —NC 1 -C 6 alkyl-; and R 14 and R 15 are each independently of the other hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy or CN; pyrimidopteridines of formula wherein R 32 , R 33 , R 34 and R 35 are each independently of one another NH 2 , OH, hydrogen, methyl, ethyl, NHCOR 37 , NHCOOR 37 , NHCONHR 37 , NHCONR 36 R 37 or phenyl which is unsubstituted or substituted by OH or NH 2 , wherein R 36 is C 1 -C 4 alkyl; phenyl which is unsubstituted or substituted by halogen, C 1 -C 4 alkyl or C 1 -C 4 -alkoxy, COR 37 , COOR 37 or CONHR 37 ; and R 37 is C 1 -C 4 alkyl or phenyl which is unsubstituted or substituted by chloro, methyl, ethyl, methoxy or ethoxy, with the proviso that R 32 and R 35 are identical, and R 33 and R 34 are identical and at least one of the pairs R 32 and R 35 or R 33 and R 34 is NH 2 or OH;