Method for Undistorted Pigmentation of Partially Crystalline Plastics

Abstract

The present invention relates to a method for colouring partially crystalline plastics in the material. The invention is characterized in that (i) a partially crystalline plastic from the group of homopolymers, terpolymers or ethylene copolymers, propylene, butylenes, styrene, and/or divinyl-benzene, polyesters, polyamides and the thermoplastic ionomers; (ii) a pigment from the group of dicetopyrrolopyrrole-, quinacridone, disazocondensation, isoindolinions and isoindoline pigments; and (iii) 0.001 to 0.25 weight part, in relation to a weight part pigment of an additive of formula (I), are formed, wherein Q is a radical of a dicetopyrrolopyrrole compound of formula (1a), wherein R14, R15, R16 and R17 independently represent hydrogen, halogen, C1-C4-alkyl, C1-C4-alkoxy, or cyano; s is a number between 0.1-4.0; and R is a radical of formula —CONZ1Z2, —NZ1Z2 or —COOZ3.

Description

This invention relates to the use of certain diketopyrrolo[3,4c]pyrrole additives in the pigmentation of partly crystalline plastics.

The coloration of partly crystalline plastics with organic pigments frequently gives rise to warpage or distortion phenomena. The pigmentation of large-volume injection moldings, especially those composed of polyethylene, leads to deformation, shrinkage and cracking (internal stresses), rendering the colored articles unusable, depending on the field of application. Bottle crates, for example, are likely to become unstackable by loss of shape.

These disadvantages relate to the majority of organic pigments, whereas inorganic pigments and a minority of organic pigments behave neutrally. It is believed that pigments act as nucleation sites during the solidification of the polymer melt and thus lead to a polymer which is prone to warp/distort.

As well as providing warpage-free colorations, pigments used for coloration of plastics have to meet high performance requirements as pigments, such as good dispersibility, high color strength, clean hues of high chroma, high thermal fastness, good resistance to bleeding and good light and weather fastnesses. It would also be desirable for pigments to be useful not just for one system but ideally universally. Thus, pigments should also be suitable for non-partly-crystalline plastics and also for coloration of other macromolecular organic materials and be useful in, for example, coating or printing systems, where still other requirements have to be met, such as for example low viscosity for the grind formulations or for the ready-produced printing and coating colors, good flocculation resistance, solvent and overcoating fastnesses, high luster and, in the case of metallic effect coatings, high transparency.

Various methods have already been proposed to counteract the warpage problem. Warpage-free pigments are obtained for example according to EP 0 952 183 A1 and WO 2004/01566 by using diketopyrrolopyrroles having long-chain substituents.

However, these methods do not always meet current requirements with regard to the performance characteristics described above. The present invention has for its object to find new ways to achieve warpage-free coloration of partly crystalline plastics with diketopyrrolopyrrole pigments.

We have found that this object is surprisingly achieved by a pigment preparation described hereinbelow.

The present invention accordingly provides a process for mass coloration of partly crystalline plastics, which comprises forming

• (i) a partly crystalline plastic from the group of the homopolymers, terpolymers or copolymers of ethylene, propylene, butylene, styrene and/or divinylbenzene, of the polyesters, of the polyamides and of the thermoplastic ionomers;
• (ii) a pigment from the group of the diketopyrrolopyrrole, quinacridone, disazocondensation, isoindolinone and isoindoline pigments; and
• (iii) 0.001 to 0.25 part by weight, based on one part by weight of pigment, of an additive of the formula (I)

QR]_s  (I)

where
Q is a residue of a diketopyrrolopyrrole compound of the formula (Ia)

where R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are independently hydrogen, halogen, for example chlorine or bromine, C₁-C₄-alkyl, for example methyl, ethyl or tert-butyl, C₁-C₄-alkoxy, for example methoxy, or cyano;
s is from 0.1 to 4.0; and
R is a radical of the formulae —CONZ¹Z², —NZ¹Z² or —COOZ³, where
Z¹ and Z² are the same or different and represent hydrogen or C₁-C₃₀-alkyl or C₂-C₃₀-alkenyl radicals, which may be linear or branched and unsubstituted or halogen, hydroxyl, hydroxycarbonyl, C₄-C₁₅-cycloalkyl or C₁-C₁₅-alkoxy substituted, alkenyl being mono- or polyunsaturated, with the proviso that Z¹ and Z² are not both hydrogen,
Z³ represents hydrogen, ammonium, alkylammonium, alkali metal, C₁-C₃₀-alkyl or C₂-C₃₀-alkenyl radicals, which may be linear or branched and unsubstituted or halogen, hydroxyl, hydroxycarbonyl, C₄-C₁₅-cycloalkyl or C₁-C₁₅-alkoxy substituted, alkenyl being mono- or polyunsaturated.

The pigment (ii) is preferably a diketopyrrolopyrrole of the formula (II)

where
R¹⁰, R¹¹, R¹² and R¹³ are independently hydrogen, halogen, for example chlorine or bromine, C₁-C₄-alkyl, for example methyl, ethyl or tert-butyl, C₁-C₄-alkoxy, for example methoxy, cyano or phenyl.

More preferably,

R¹¹ and R¹³ are each hydrogen and
R¹⁰ and R¹², which are the same or different, are each hydrogen, methyl, tert-butyl, chlorine, cyano or phenyl.

Examples of pigments (ii) are C.I. Pigment Orange 71, 73, 81, Pigment Red 254, 255, 264, 270, 272, Pigment Yellow 139, Pigment Violet 19, 37, Pigment Blue 15.

Preferred additives are those wherein

Z¹ and Z², which are the same or different, are each C₂-C₁₈-alkyl or C₂-C₁₈-alkenyl,
Z³ is C₂-C₁₈-alkyl or C₂-C₁₈-alkenyl,
R¹⁴ and R¹⁶ are each hydrogen, and
R¹⁵ and R¹⁷ are each hydrogen, methyl, tert-butyl, chlorine or cyano.

Preferred additives are further those wherein s is from 0.2 to 3.0 and in particular from 0.5 to 2.5.

Coloration in accordance with the present invention utilizes advantageously 0.0001 to 0.5 part by weight, especially 0.0002 to 0.05 part by weight and more preferably 0.0005 to 0.01 part by weight of pigment plus additive of the formula (I), based on one part by weight of the partly crystalline plastic. When master batches are to be colored, about 0.05 to 0.5 part by weight of pigment plus additive of the formula (I), based on one part by weight of the partly crystalline plastic, is used.

To achieve the desired absence of warpage, it is advantageous to use 0.001 to 0.25 part by weight, in particular 0.01 to 0.15 part by weight and more preferably 0.02 to 0.1 part by weight of the additive of the formula (I), based on one part by weight of pigment.

The additives of the present invention are preparable in a conventional manner. This involves appropriately substituted nitrites being reacted with succinic diesters and strong bases in a suitable solvent similarly to the process described in EP-A-0 094 911

As well as the constituents mentioned, 0 to 0.5 part by weight and preferably 0.001 to 0.1 part by weight, based on one part by weight of the mixture of plastic and pigment, can be used of at least one further auxiliary from the group of the surfactants, pigmentary and nonpigmentary dispersants, fillers, standardizers, resins, waxes, defoamers, antidust agents, extenders, shading colorants, preservatives, drying retarders, rheology control additives, wetting agents, antioxidants, UV absorbers, and light stabilizers.

Useful surfactants include anionic or anion-active, cationic or cation-active and nonionic substances or mixtures of these agents.

Examples of suitable anion-active substances include fatty acid taurides, fatty acid N-methyltaurides, fatty acid isethionates, alkylphenylsulfonates, alkylnaphthalene-sulfonates, alkylphenol polyglycol ether sulfates, fatty alcohol polyglycol ether sulfates, fatty acid amide polyglycol ether sulfates, alkylsulfosuccinamates, alkenylsuccinic monoesters, fatty alcohol polyglycol ether sulfosuccinates, alkanesulfonates, fatty acid glutamates, alkylsulfosuccinates, fatty acid sarcosides; fatty acids, examples being palmitic, stearic and oleic acid; soaps, examples being alkali metal salts of fatty acids, naphthenic acids and resin acids, such as abietic acid, alkali-soluble resins, examples being rosin-modified maleate resins and condensation products based on cyanuric chloride, taurine, N,N′-diethylaminopropylamine and p-phenylenediamine. Particular preference is given to resin soaps, i.e., alkali metal salts of resin acids.

Examples of suitable cation-active substances include quaternary ammonium salts, fatty amine alkoxylates, alkoxylated polyamines, fatty amine polyglycol ethers, fatty amines, diamines and polyamines derived from fatty amines or fatty alcohols, and the alkoxylates of said amines, imidazolines derived from fatty acids, and salts of these cation-active substances, such as acetates, for example. Examples of suitable nonionic substances include amine oxides, fatty alcohol polyglycol ethers, fatty acid polyglycol esters, betaines, such as fatty acid amide N-propyl betaines, phosphoric esters of aliphatic and aromatic alcohols, fatty alcohols or fatty alcohol polyglycol ethers, fatty acid amide ethoxylates, fatty alcohol-alkylene oxide adducts and alkylphenol polyglycol ethers.

The pigments (ii) and additives (iii) and also any further auxiliaries that are used in the process of the present invention can be used in the form of a pigment preparation from these components. Generally, a pigment preparation comprises solid systems of free-flowing, pulverulent constitution, or comprises granules. However, aqueous or solvent-containing presscakes are also possible as are plastics concentrates (master batch).

The pigment preparation can be produced via the additive or a mixture of these additives and the pigment or a mixture of pigments being mixed with each other or being allowed to act on each other during their manufacturing operation. The manufacturing operation of a diketopyrrolopyrrole pigment for example comprises its synthesis, fine division and/or dispersion, for example by grinding, kneading or reprecipitating, if appropriate finishing, and also isolation as a presscake or as a dry granulate or powder. Manufacturing operations of other base pigments are known from the literature. For example, the additive can be added before, during or after one of the customary processing steps such as for example synthesis, fine-dividing operation, finishing, isolating, drying or pulverizing. For instance, addition at as early a stage as the synthesis can lead to fine particles. It will be appreciated that the additive may also be added in subdivided portions at different times.

When the additive is added in the course of a fine-dividing operation, it is added for example before or during salt kneading, before or during dry grinding of a crude pigment or before or during wet grinding of a crude pigment.

It will be similarly advantageous to add the additive before or after finishing of the base pigment in an aqueous or aqueous-organic medium at any desired pH or in an organic medium.

The additive may also be added to the preferably water-moist pigment presscake prior to drying and incorporated, in which case the additive itself may likewise be present as presscake. It is further possible to effect dry mixes of powder or a granulate of the additive with the powder or granulate of the pigment, or to achieve the mixing in the course of a grinding or pulverization of the pigment and of the additive.

The warpage amelioration achievable according to the present invention is believed to be due to a modification of the surface structure of the base pigment via the additive. There are a whole series of cases where the efficacy of the additive, and the quality of the pigment preparations produced therewith, are dependent on the time of addition of the additive in the base pigment's manufacturing operation. When two or more additives are used, they may be added at the same or at different times or may be mixed before being added. The efficacy of the additive may also depend on its particle size and particle shape and also on the percentage of the pigment surface which is coatable. It may be preferable for the additive to be added to the pigment only in the contemplated application medium. The respective optimum concentration for the additive has to be determined in preliminary, exploratory tests, since the improvement in the properties of the pigments does not always correlate linearly with the amount of additive.

As used herein, the term “warpage-free” is to be understood as meaning a degree of warpage which is distinctly reduced compared with the untreated pigment.

Partly crystalline plastics is to be understood as referring to those which solidify to form small crystalline nuclei or aggregates, including those which do so only in the presence of nucleating agents (organic pigments for example). Partly crystalline plastics are generally thermoplastic macromolecular organic materials having a molecular weight (M_w) of 10⁴ to 10⁸ g/mol, preferably 10⁵ to 10⁷ g/mol, and a crystallinity (X_c) of 10 to 99.9%, preferably of 40 to 99% and more preferably of 80 to 99%. Preferred partly crystalline plastics are homopolymers, block or random copolymers and terpolymers of ethylene, propylene, butylene, styrene and/or divinylbenzene, especially polyolefins, such as polyethylene (HDPE, MDPE, LDPE), polypropylene, especially high density polyethylene (HDPE), also polystyrene, PVC, polyesters, such as polyethylene terephthalate, and polyamides, such as nylon 6 and nylon 66, and thermoplastic ionomers. The partly crystalline plastics may further comprise additives in customary amounts, examples being stabilizers, optical brighteners, fillers and lubricants.

The forming of the plastic can be effected by means of an extrusion or injection molding process. In the extrusion molding process, the polymer is first plasticated in an extruder and subsequently pressed through a suitable die for shaping. This process can be used to produce for example various profiles, such as flat, hollow, open or solid profiles. In the injection molding process, the molten, plasticated polymer is injected into a mold whose cavity has the shape and size of the desired article. After the polymer has cooled, the mold is opened and the final article is removed.

The influence on the warpage propensity of polyolefin by the pigment preparation is tested on a ready-produced injection molding in the form of a plaque on the lines of DIN EN ISO 294-4. After aging, the dimensions of the plaque (length, width) are measured and the degree of warpage is determined.

Pigment preparations comprising (ii) a diketopyrrolopyrrole pigment, preferably of the aforementioned formula (II), in particular C.I. Pigment Red 254; and (iii) 0.001 to 0.25 part by weight, based on one part by weight of pigment, of an additive of the formula (I)

QR]_s  (I)

where
Q is a residue of a diketopyrrolopyrrole compound of the formula (Ia)

where R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are independently hydrogen, halogen, C₁-C₄-alkyl, C₁-C₄-alkoxy, or cyano;
s is from 0.1 to 4.0; and
R is a radical of the formula —CONZ¹Z²,
where
Z¹ and Z² are the same or different and represent hydrogen or C₁-C₃₀-alkyl or C₂-C₃₀-alkenyl radicals, which may be linear or branched and unsubstituted or halogen, hydroxyl, hydroxycarbonyl, C₄-C₁₅-cycloalkyl or C₁-C₁₅-alkoxy substituted, alkenyl being mono- or polyunsaturated, with the proviso that Z¹ and Z² are not both hydrogen,
are novel and likewise form part of the subject matter of the present invention.

The pigment preparations of the present invention possess ameliorated warpage characteristics compared with the mixtures described in WO 2004/01566.

In addition, the pigment preparations of the present invention have an enhanced DIN EN 12877 thermal stability compared with the mixtures described in EP 0 952 183 A1.

In the examples which follow, percentages are by weight, unless otherwise stated.

EXAMPLE 1a

30 g of 3-cyanobenzoic acid are refluxed for 4 hours in 300 g of thionyl chloride. The thionyl chloride is distilled off in a water jet vacuum and the residue is taken up in 200 ml of 1,4-dioxane. Addition of 16.6 g of pyridine and 18.3 g of methylbutylamine is followed by 45 minutes of stirring at room temperature. The solution is extracted with 200 ml of dichloromethane and 200 ml of 10% aqueous NaOH and the product (III) is isolated from the dichloromethane phase.

EXAMPLE 1b

Additive of formula (IV) is prepared by the method disclosed in EP-A-0 094 911, by reaction of the benzonitrile (III) with diisopropyl succinate in the presence of sodium amylate in amyl alcohol. In this reaction, 6.9 g of sodium are reacted in 200 g of amyl alcohol at the boil. 43.6 g of the benzonitrile (III) are dissolved in the resulting sodium amylate, and 20.2 g of diisopropyl succinate are added dropwise at 100° C. in the course of 150 minutes. A further 6 hours of stirring at 100° C. is followed by pouring onto 200 g of water, removal of the amyl alcohol by steam distillation, before the product (IV) is isolated by filtration and washed with water.

95 parts of P.R.254 (®Irgazin Rot BO) are mixed with 5 parts of additive of formula (IV). The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

Method: Shrinkage testing of organic pigments in injection-molded polyethylene. A rectangular plaque is molded with film gate and the dimensions 60 by 60 mm. Evaluation is by measurement along and across the direction of molding. For each pigment tested 10 moldings were produced and measured out, the respective average value being employed. The control used is 10 moldings from nonpigmented plastic. It is very important in this connection that this material experience exactly the same processing history as the pigmented system.

The polyethylene plaques pigmented with the pigment preparation of the present invention have a distinctly lower warpage value than the above P.R.254 (®Irgazin Rot BO) without additive.

EXAMPLE 2a

10 g of 3-cyanobenzoic acid are refluxed for 4 hours in 100 g of thionyl chloride. The thionyl chloride is distilled off in a water jet vacuum and the residue is taken up in 100 ml of 1,4-dioxane. Addition of 5.4 g of pyridine and 16.87 g of dioctylamine is followed by 1 hour of stirring at 80° C. The solution is extracted with 150 ml of dichloromethane and 100 ml of 10% aqueous NaOH and the product (V) is isolated from the dichloromethane phase.

EXAMPLE 2b

Additive of formula (VI) is prepared by the method disclosed in EP-A-0 094 911, by reaction of the benzonitrile (V) with diisopropyl succinate in the presence of sodium amylate in amyl alcohol, similarly to Example 1b.

95 parts of P.R.254 (®Irgazin Rot BO) are mixed with 5 parts of additive of formula (VI). The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The polyethylene plaques pigmented with the inventive pigment preparation have a distinctly lower warpage value than the above P.R.254 (®Irgazin Rot BO) without additive.

EXAMPLE 3a

10 g of 3-cyanobenzoic acid are refluxed for 4 hours in 100 g of thionyl chloride. The thionyl chloride is distilled off in a water jet vacuum and the residue is taken up in 100 ml of 1,4-dioxane. Addition of 5.4 g of pyridine and 12.67 g of dicyclohexylamine is followed by 1 hour of stirring at 80° C. The solution is extracted with 150 ml of dichloromethane and 100 ml of 10% aqueous NaOH and the product (VII) is isolated from the dichloromethane phase.

EXAMPLE 3b

Additive of formula (VIII) is prepared by the method disclosed in EP-A-0 094 911, by reaction of the benzonitrile (VII) with diisopropyl succinate in the presence of sodium amylate in amyl alcohol, similarly to Example 1b.

95 parts of P.R.254®Irgazin Rot BO) are mixed with 5 parts of additive of formula (VIII). The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The polyethylene plaques pigmented with the inventive pigment preparation have a distinctly lower warpage value than the above P.R.254 (®Irgazin Rot BO) without additive.

EXAMPLE 4a

10 g of 3-cyanobenzoic acid are refluxed for 4 hours in 100 g of thionyl chloride. The thionyl chloride is distilled off in a water jet vacuum and the residue is taken up in 100 ml of 1,4-dioxane. Addition of 5.4 g of pyridine and 12.95 g of dodecylamine is followed by 1 hour of stirring at 80° C. The solution is extracted with 150 ml of dichloromethane and 100 ml of 10% aqueous NaOH and the product (IX) is isolated from the dichloromethane phase.

EXAMPLE 4b

Additive of formula (X) is prepared by the method disclosed in EP-A-0 094 911, by reaction of the benzonitrile (IX) with diisopropyl succinate in the presence of sodium amylate in amyl alcohol, similarly to Example 1b.

95 parts of P.R.254 (®Irgazin Rot BO) are mixed with 5 parts of additive of formula (X). The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The polyethylene plaques pigmented with the inventive pigment preparation have a distinctly lower warpage value than the above P.R.254 (®Irgazin Rot BO) without additive.

EXAMPLE 5

Additive (XI) is prepared by the method disclosed in EP-A-0 353 184. To this end, 5 g of 1,4-diketo-3,6-bis(4-bromophenyl)pyrrolo[3,4-c]pyrrole, 7.81 g of n-methyl-butylamine and 100 ml of anhydrous N-methylpyrrolidone are introduced into a 1000 ml Teflon autoclave as initial charge under nitrogen. The suspension is heated to 200° C. in the course of 2 hours with moderate stirring and held at 200° C. for 24 hours with moderate stirring. The reaction mass is then cooled down to room temperature, the autoclave is opened, and the suspension is filtered off with suction. The filter cake is washed in succession with N-methylpyrrolidone, methanol und hot water and dried in a vacuum drier cabinet at 80° C. for 24 hours.

95 parts of P.R.254 (®Irgazin Rot BO) are mixed with 5 parts of additive of formula (XI). The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The polyethylene plaques pigmented with the inventive pigment preparation have a distinctly lower warpage value than the above P.R.254 (®Irgazin Rot BO) without additive.

EXAMPLE 6a

10 g of 3-cyanobenzoic acid are refluxed for 4 hours in 100 g of thionyl chloride. The thionyl chloride is distilled off in a water jet vacuum and the residue is taken up in 100 ml of 1,4-dioxane. Addition of 5.4 g of pyridine and 11.06 g of decanol is followed by 1 hour of stirring at 80° C. The solution is extracted with 150 g of dichloromethane and 100 g of 10% aqueous NaOH and the product (XII) is isolated from the dichloromethane phase.

EXAMPLE 6b

95 parts of P.R.254 (®Irgazin Rot BO) are mixed with 5 parts of additive obtained by reaction of the benzonitrile (XII) with diisopropyl succinate in the presence of sodium amylate in the amyl alcohol similarly to Example 1b.

The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The polyethylene plaques pigmented with the inventive pigment preparation have a distinctly lower warpage value than the above P.R.254 (®Irgazin Rot BO) without additive.

EXAMPLE 7

Comparison

95 parts of P.R.254 (®Irgazin Rot BO) are mixed with 5 parts of the additive of the formula (XIII) described in WO 2004/01566.

The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The pigmented polyethylene plaques have a distinctly higher warpage value than the mixtures described in Example 1b polyethylene plaques pigmented with the inventive pigment preparation.

EXAMPLE 8

Comparison

95 parts of P.R.254 (®Irgazin Rot BO) are mixed with 5 parts of the additive of the formula (XIV) described in EP 0 952 183 A1.

The P.R 254 additized with the additive (XIV) has a lower DIN EN 12877 thermal resistibility than the polyethylene plaques pigmented with the inventive pigment preparation.

EXAMPLE 9

95 parts of P.V.19 (®PV-Echtviolett ER) are mixed with 5 parts of additive of the formula (IV) (Example 1b).

The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The polyethylene plaques pigmented with the inventive pigment preparation have a lower warpage value than the above P.V 19 (®PV-Echtviolett ER) without additive.

EXAMPLE 10

95 parts of P.Y. 139 (®PV-Echtgelb H2R) are mixed with 5 parts of additive of the formula (IV) (Example 1b).

The pigment preparation is used to pigment polyethylene plaques (600 g of ®Hostalen GC7260 and 0.6 g of pigment preparation) and warpage is determined on the lines of DIN EN ISO 294-4.

The polyethylene plaques pigmented with the inventive pigment preparation have a lower warpage value than the above P.Y. 139 (®PV-Echtgelb H2R) without additive.

Claims

1. A process for mass coloration of partly crystalline plastics, which comprises forming where

(i) a partly crystalline plastic selected from the group consisting of the homopolymers, terpolymers or copolymers of ethylene, propylene, butylene, styrenes divinylbenzene, polyesters, polyamides and thermoplastic ionomers and mixtures thereof;

(ii) a pigment selected from the group consisting of diketopyrrolopyrrole, quinacridone, disazocondensation, isoindolinone and isoindoline pigments; and

(iii) 0.001 to 0.25 part by weight, based on one part by weight of pigment, of an additive of the formula (I) QR]s   (I)

where

Q is a residue of a diketopyrrolopyrrole compound of the formula (Ia)

where R14, R15, R16 and R17 are independently hydrogen, halogen, C1-C4-alkyl, C1-C4-alkoxy, or cyano;

s is from 0.1 to 4.0; and

R is a radical of the formulae —CONZ1Z2, —NZ1Z2 or —COOZ3,

Z1 and Z2 are the same or different and represent hydrogen or C1-C30-alkyl or C2-C30-alkenyl radicals, which may be linear or branched and unsubstituted or halogen, hydroxyl, hydroxycarbonyl, C4-C15-cycloalkyl or C1-C15-alkoxy substituted, alkenyl being mono- or polyunsaturated, with the proviso that Z1 and Z2 are not both hydrogen,

Z3 represents hydrogen, ammonium, alkylammonium, alkali metal, C1-C30-alkyl or C2-C30-alkenyl radicals, which may be linear or branched and unsubstituted or halogen, hydroxyl, hydroxycarbonyl, C4-C15-cycloalkyl or C1-C15-alkoxy substituted, alkenyl being mono- or polyunsaturated.

2. A process according to claim 1, wherein said pigment (ii) is a diketopyrrolopyrrole of the formula (II) where

R10, R11, R12 and R13 are independently hydrogen, halogen, C1-C4-alkyl, C1-C4-alkoxy, cyano or phenyl.

3. The process according to claim 2, wherein

R11 and R13 are each hydrogen and

R10 and R12, which are the same or different, are each hydrogen, methyl, tert-butyl, chlorine, cyano or phenyl.

4. The process according to claim 1, wherein said pigment (ii) is selected from the group consisting of C.I. Pigment Orange 71, 73, 81, Pigment Red 254, 255, 264, 270, 272, Pigment Yellow 139, Pigment Violet 19, 37, and Pigment Blue 15.

5. The process according to claim 1, wherein

Z1 and Z2, which are the same or different, are each C2-C18-alkyl or C2-C18-alkenyl,

Z3 is C2-C18-alkyl or C2-C18-alkenyl,

R14 and R16 are each hydrogen, and

R15 and R17 are each hydrogen, methyl, tert-butyl, chlorine or cyano.

6. The process according to claim 1, wherein s is from 0.5 to 2.5.

7. The process according to claim 1, which utilizes 0.0001 to 0.5 part by weight of pigment plus additive of the formula (I), based on one part by weight of the partially crystalline plastic.

8. The process according to claim 1, which utilizes 0.02 to 0.1 part by weight of the additive of the formula (I), based on one part by weight of pigment.

9. The process according to claim 1, which utilizes up to 0.5 part by weight, based on one part by weight of the combination of plastic and pigment, of at least one further auxiliary selected from the group consisting of surfactants, pigmentary and nonpigmentary dispersants, fillers, standardizers, resins, waxes, defoamers, antidust agents, extenders, shading colorants, preservatives, drying retarders, rheology control additives, wetting agents, antioxidants, UV absorbers, and light stabilizers.

10. The process according to claim 1 wherein the partly crystalline plastic is selected from the group consisting of HDPE, MDPE, LDPE, polypropylene, PVC, PET, nylon 6 and nylon 66.

11. The process according to claim 1, wherein said forming step takes place by an extrusion or injection molding process.

12. A pigment preparation comprising where

(ii) a diketopyrrolopyrrole pigment and

(iii) 0.001 to 0.25 part by weight, based on one part by weight of pigment, of an additive of the formula (I) QR]s  (I)

Q is a residue of a diketopyrrolopyrrole compound of the formula (Ia)

where R14, R15, R16 and R17 are independently hydrogen, halogen, C1-C4-alkyl, C1-C4-alkoxy, or cyano;

s is from 0.1 to 4.0; and

R is a radical of the formula —CONZ1Z2,

where

Z1 and Z2 are the same or different and represent hydrogen or C1-C30-alkyl or C2-C30-alkenyl radicals, which may be linear or branched and unsubstituted or halogen, hydroxyl, hydroxycarbonyl, C4-C15-cycloalkyl or C1-C15-alkoxy substituted, alkenyl being mono- or polyunsaturated, with the proviso that Z1 and Z2 are not both hydrogen.

13. The pigment preparation according to claim 12, wherein said diketopyrrolopyrrole pigment (ii) is C.I Pigment Red 254.