Patent Application
20080108735
Method for treating phthalocyanine pigments for the weatherable and light-resisting pigmentation of plastic materials
When plastics, in particular PVC, have been pigmented with phthalocyanine pigments, a prolonged period of weathering often leads to formation of brownish-black discolored areas in the plastic. These discolored areas are possibly brought about by degradation reactions catalyzed by contaminants present in trace quantities in the pigment. These contaminants pass into the pigments either by way of the raw materials or catalysts used or as a consequence of a process.
It was therefore an object of the present invention to develop a process which can treat phthalocyanine pigments which are suitable for weather-resistant and lightfast pigmentation of plastics, in particular of PVC, without altering the coloristic properties of the pigments.
Surprisingly, it has been found that the process described below achieves this object.
The invention provides a process for treating phthalocyanine pigments, which comprises
The pigments thus treated are generally then dried and finished in a manner appropriate to the application sector.
Phthalocyanine pigments that can be used are metallic, metal free, halogenated, and non-halogenated phthalocyanines, examples being C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, C.I. Pigment Green 7 or 36.
The pigments are generally used in dry form, as crude pigment or finished pigment. However, use in the form of press cake comprising water or comprising solvent is also possible.
For the inventive treatment, it is advantageous to use from 0.01 to 0.5 part by weight, in particular from 0.05 to 0.15 part by weight, of pigment, based on one part by weight of liquid medium.
The form in which the hydrochloric acid is used is advantageously that of aqueous HCl of strength from 5 to 35% by weight, in particular from 15 to 25% by weight.
The organic solvent used is an organic solvent containing a carbonyl function and/or ether function, preferably aliphatic, aromatic, or araliphatic ketones, aldehydes, ethers, or glycol ethers, examples being:
Among the organic liquids, preference is given to those which are not miscible with the aqueous liquid comprising hydrochloric acid. This permits easy separation, and return to the process, of the lower- or higher-density organic phase of the filtrate.
Another factor to be considered during selection of the organic liquids is that they do not enter into any chemical reactions with the other components. The amount preferably used of the organic solvent is from 0.05 to 5 parts by weight, in particular from 0.5 to 1.5 parts by weight, based on one part by weight of aqueous hydrochloric acid.
Alongside the constituents mentioned, it is also possible to add from 0 to 0.5 part by weight, preferably from 0.01 to 0.1 part by weight, based on one part by weight of the suspension, of at least one other auxiliary from the group of the surfactants, non-pigmentary and pigmentary dispersing agents, antifoams, wetting agents, alcohols, antioxidants, UV absorbers, waxes, and light stabilizers.
The inventively treated phthalocyanines can be used for coloring polymers, such as PVC, polyolefins, PA, PUR, PMMA, polyester, or PVC, preferably for coloring PVC, and known processes are used here for pigmentation, if appropriate via addition of additives and auxiliaries known to the person skilled in the art, e.g. via injection molding, extrusion, or hot-roll processes. The inventively treated phthalocyanine pigment here can be used in the form of powder or pellets or masterbatch, or in the form of a preparation.
In particular, PVC pigmented with the inventively treated phthalocyanine can be used for producing window profiles, floorcoverings, or packaging, e.g. of food or drink, or else can be used for pipes for drainage, drinking-water lines, waste-water lines, cable ducts, and electrical installations, or else PVC foils.
The present invention therefore also provides a plastic pigmented with the inventively treated phthalocyanine pigment, preferably PVC, polyolefins, PA, PUR, PMMA or polyester.
15 g of C.I. Pigment Blue 15:3 were dispersed in a mixture composed of 150 ml of hydrochloric acid (6 molar) and 150 ml of methyl isobutyl ketone (MIBK) for 15 min and then stirred at 90° C. for 30 min. After cooling, stirring was continued with ice-bath cooling for 30 min, and the suspension was filtered and washed with 50 ml of methyl isobutyl ketone, 100 ml of hot water (about 70° C.), and 50 ml of methanol. The resultant press cake was dried in a vacuum drying cabinet at 80° C. for 12 h and ground.
The purified pigment exhibits unaltered coloristic properties.
15 g of C.I. Pigment Blue 15:3 were dispersed in a mixture composed of 150 ml of hydrochloric acid (6 molar) and 150 ml of methyl isobutyl ketone for 15 min and then stirred at 40° C. for 30 min. After cooling, stirring was continued with ice-bath cooling for 30 min, and the suspension was filtered and washed with 50 ml of methyl isobutyl ketone, 100 ml of hot water (about 70° C.), and 50 ml of methanol. The resultant press cake was dried in a vacuum drying cabinet at 80° C. for 12 h and ground.
The purified pigment exhibits unaltered coloristic properties.
15 g of C.I. Pigment Blue 15:3 were dispersed in a mixture composed of 150 ml of hydrochloric acid (6 molar) and 150 ml of diethylene glycol dimethyl ether for 15 min and then stirred at 90° C. for 30 min. After cooling, stirring was continued with ice-bath cooling for 30 min, and the suspension was filtered and washed with 50 ml of diethylene glycol dimethyl ether (DGDME), 100 ml of hot water (about 70° C.), and 50 ml of methanol. The resultant press cake was dried in a vacuum drying cabinet at 80° C. for 12 h and ground.
The purified pigment exhibits unaltered coloristic properties.
20 g of C.I. Pigment Green 7 were purified by analogy with example 1. The purified pigment exhibits unaltered coloristic properties.
100 parts of a PVC mixture in powder form are mixed with 0.1 part of pigment from example 1 in a vessel for 10 minutes. The mixture is then charged to a roll mill and plastified at 130° C. (roll-surface temperature) and converted to a peelable form. After roll-milling, a rectangular piece is cut off from the milled sheets peeled from the roll and weathered to DIN EN ISO 4892 (filtered xenon-arc radiation, simultaneous weathering, equipment: Atlas Weather-Ometer).
After weathering to DIN EN ISO 4892 for 8000 hours, no brownish-black discolored areas arise in the plastic, unlike with Pigment Blue 15:3 which has not been inventively treated.
By analogy with example 5, a PVC foil is produced with the pigment from example 2 and weathered. After weathering to DIN EN ISO 4892 for 8000 hours, no brownish-black discolored areas arise in the plastic, unlike with Pigment Blue 15:3 which has not been inventively treated.
By analogy with example 5, a PVC foil is produced with the pigment from example 3 and weathered. After weathering to DIN EN ISO 4892 for 8000 hours, no brownish-black discolored areas arise in the plastic, unlike with Pigment Blue 15:3 which has not been inventively treated.
By analogy with example 5, a PVC foil is produced with the pigment from example 4 and weathered. After weathering to DIN EN ISO 4892 for 8000 hours, no brownish-black discolored areas arise in the plastic, unlike with Pigment Green 7 which has not been inventively treated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 059 863.0 | Dec 2004 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP05/12206 | 11/15/2005 | WO | 00 | 6/8/2007 |
