Pigment preparations containing an organic pigment, method for their manufacture and their use in colouring thermoplastic materials.

p0001The present invention relates to novel pigment preparations comprising an organic pigment as a support material polymers based on methacrylate, a polymeric plasticizer and a dispersing agent, a process for their preparation and their use for coloring thermoplastics.

p0002The coloring of thermoplastics by means of pigment preparations is carried out in the plastics processing industry for many years. Compared to the use of untreated pigments, the pigment preparations offer the advantage of a homogeneous and defect-free coloring of the plastic substrate. One reaches in this way a good pigment dispersion and allow full utilization of the color strength. In addition, the use of pigment preparations allows a dust-free working.

p0003Subject matter of DE-A-2941 8O7 are preparations containing the exhibit as carrier polymers based on methacrylate with a molecular weight of 1OO OOO to 7OO OOO and contain a polymer plasticizers based on esters of polyalcohols with polyfunctional acids transparent iron oxides. However, the content of iron oxide in these preparations is only about 2O wt .-%.

p0004Also, most of the pigment preparations that contain organic pigments have a pigment content, which is of this order (in general, up to about 3O wt .-%).

p0005Special pigment preparations which contain a proportion of organic pigment of about 5O percent .-% are limited to the scope of polyolefins.

p0006In addition to the low content of organic pigment, a further disadvantage of conventional pigment preparations can be seen in the fact that they are each only suitable for coloring a precisely defined polymer region or in a specific processing technology in general.

p0007Object of the present invention was to provide novel pigment preparations which have a high proportion of organic pigment and that are universally suitable for the coloring of thermoplastics.

p0008Surprisingly, novel pigment preparations 5O have now been found, containing up to 75 wt .-% of an organic pigment as a support material, polymers based on methyl and / or butyl methacrylate, having a molecular weight of 1OOOOO to 2OOOOO, a polymer plasticizers based on full esters of polyalcohols with polyfunctional acids and a dispersing agent based on partial esters of polyhydric alcohols with fatty acids.

p0009Which serve as carrier material, polymers based on methyl and / or methacrylate to a molecular weight of 1OO OOO to 2OO OOO, preferably from 1OO OOO to 15O OOO.

p0010As polymeric plasticizers used products based on full esters of polyalcohols with polyfunctional acids. Suitable polyalcohols are for example propane-1,3-diol, butane-1,4-diol or pentaerythritol. Polyfunctional acids, for example adipic acid or phthalic acid are also suitable. The molecular weight of the polymer plasticizer may vary in terms of their changing composition of course; however, be achieved with a molecular weight of up to 2OOO 6OOO good results generally with the use of components.

p0011Preferably plasticizers are based on adipic acid, up 6OOO and in particular about 6 (measured at 25 ° C) a molecular weight of up to 2OOO 6OOO, preferably 4OOO OOO OOO and a viscosity of 3O to 4O mPa.s OOO. The alcohol component is preferably 1,4-butane diol.

p0012Such plasticizers have in addition to their excellent softening and good wetting properties the advantage of extremely low volatility.

p0013As dispersing agents are the partial esters of polyols with fatty acids. Suitable polyalcohols include, for example butane-1,4-diol, and particularly pentaerythritol. Suitable acid components are fatty acids, particularly C₁₂-C₁₈-fatty acids, with stearic acid being particularly preferred.

p0014Examples of the partial esters may be mentioned stearic acid and pentaerythritol, with 1 molar equivalent of pentaerythritol was esterified with 2 mol equivalents of stearic acid. The HLB value of this component (hydrophile-lipophile balance) in this case is 8.7.

p0015Preferably contain the pigment preparations inventive carrier material, polymeric plasticizers and dispersing in a weight ratio O, 5: O, 5: 1 to 4: 3: 1, especially 1: 1: 1 to 4: 3: 1.

p0016The new pigment preparations according to the invention containing 5O% to 75 wt .- an organic pigment. Organic pigments, for example, a known monoazo (eg products derived from acetoacetarylide or of .beta.-naphthol derivatives), laked monoazo dyes, disazo pigments, condensed disazo pigments, isoindoline derivatives, derivatives of naphthalene or perylene, anthraquinone, thioindigo, quinacridones, dioxazine or phthalocyanine into consideration.

p0017The pigment preparations according to the invention are advantageously obtained when plasticized organic pigment, support material, polymeric plasticizers and dispersing at a temperature of 12O to 15O ° C and then dispersed at a temperature of 8O to 12O ° C. This achieves the high pigment absorption and simultaneously has the possibility of bringing the preparation into a softening range of about 8O to 13O ° C.

p0018Advantageously carried out the inventive method in a dispersing apparatus in a continuous or batch process employed by.

p0019Depending on requirements, the inventive highly concentrated pigment formulation can be transferred to the respective desired delivery form, eg by means of water-granulation in a granular form or by grinding into a powder form.

p0020Further dilution with most commercially available polymers, eg possible in a continuously operating extruder.

p0021The pigment preparations according to the invention may be used advantageously without any further dispersing steps for coloring thermoplastics, such as polyvinyl chloride, polyolefins, styrene polymers, polyamide, polycarbonate, polyethylene terephthalate or polybutylene terephthalate.

p0022The following examples are intended to illustrate the invention.

example 1

p0023Butane-1,4-diol esterified 42 g of a copolymer of methyl methacrylate and butyl methacrylate having a molecular weight of 1OOOOO, 27 g of a plasticizer based on adipic acid and having a molecular weight of about 6OOO, and 21 g of a dispersant based on two times with stearic acid pentaerythritol were mixed with 21O g of CI pigment Yellow 183 mixed in an internal mixer, is plasticized at a temperature of 15O ° C and dispersed with no further supply of energy during 2 hours at a temperature of 1OO ° C. The resulting product (pigment content 5O percent .-% was crushed and ground and then to a low-dust preparation (particle diameter <5OO μ). In the coloring of polypropylene to obtain speck-free products. The good pigment fineness is also reflected in the color strength. Compared to the initial pigment gave a chroma gain of x 12% (dispersion test according to DIN 53 775, part 7 = O).

example 2

p0024esterified 34 g of a copolymer of methyl methacrylate and butyl methacrylate having a molecular weight of 1OOOOO, 36 g of a plasticizer based on adipic acid and butane-1,4-diol with a molecular weight of about 6OOO, and 3O g of a dispersant based on two times with stearic acid pentaerythritol were together with 1OO g CI pigment Red 149 as in example 1 prepared (pigment content 5O percent .-%). In the coloring of ABS to give speck-free products. Opposite the exit pigment was obtained by a color strength gain of + 8% (dispersion harshness = O).

example 3

p0025esterified 6O g of a copolymer of methyl methacrylate and butyl methacrylate having a molecular weight of 1OOOOO, 45 g of a plasticizer based on adipic acid and butane-1,4-diol with a molecular weight of about 6OOO, and 15 g of a dispersant based on two times with stearic acid pentaerythritol were mixed with 18O g of CI pigment Blue 15: 3 prepared analogously to example 1 (pigment content 6O wt .-%). With a blend of one part by weight of the preparation with 1O parts by weight of titanium dioxide to give a color strength gain of c 7% compared to the starting pigment (dispersion harshness = O).