CS229111B1 - Pigment preparation for coloring plastics - Google Patents

Abstract

Pigment preparation for coloring plastics containing 10 to 80% by weight of pigment, 15 to 75% by weight of filler, 1 to 20% by weight of calcium salt of aliphatic monocarboxylic acid with a number of carbon atoms of 10 to 26 and 5 to 60% by weight of aliphatic monocarboxylic acid with a number of carbon atoms of 10 to 26 or a mixture of these acids. Pigment preparations for coloring polyethylene, polypropylene, etc. in bulk, which are easily dispersible, have a high yield and their application does not impair the mechanical properties of the colored products.

Description

The invention relates to pigment preparations for coloring plastic materials, especially polyolefins, in bulk. Coloring polyolefins, e.g. polyethylene, polypropylene, polystyrene, polyvinyl chloride, etc., with powdered organic or inorganic pigments is associated with difficulties both in terms of handling during application and, above all, in terms of the dispersibility of the pigment in a given polyolefin. When coloring with pure powdered pigments, clusters of pigment particles often form in the polymer material, which means that its coloring ability is not utilized (the yield decreases), the mechanical properties of the colored product deteriorate, etc. Partial elimination of these shortcomings can be achieved by preparing pigment preparations, i.e. effective pre-dispersion of the pigment in the polymer material (carrier). This is carried out in kneaders at elevated temperatures, which is a technology that is very energy-intensive.

Research has now found that very good dispersibility of the pigment in plastics can be achieved by using pigment preparations according to the present invention, which contain a water-soluble and water-soluble pigment, 15 to 75% filler, 1 to 20% calcium salt of an aliphatic monocarboxylic acid having a number of carbon atoms of 10 to 26 and 5 to 60% aliphatic monocarboxylic acid having a number of carbon atoms of 10 to 26 or a mixture of these acids.

The pigment preparation for coloring plastics contains 10 to 80% by weight of pigment, and organic pigments such as azo, azo condensation, anthraquinone, flavanthrone, indanthrone, dioxazine, phthalocyanine, tetrachloroisoindoline, etc. can be used, both alone and in various mixtures.

Inorganic pigments such as titanium white, carbon black, etc. can also be used to prepare the pigment preparations according to the invention.

229 111

- 2 iron oxides, cadmium pigments, etc. both alone and in combination with organic pigments.

The pigment preparations according to the invention contain 15 to 75% by weight of filler, which may be calcium carbonate as ground limestone or in precipitated form, or as chalk, magnesium carbonate, talc, etc.

Pigment preparations for coloring plastics contain 1 to 20% by weight of the calcium salt of an aliphatic monocarboxylic acid and 5 to 60% by weight of an aliphatic monocarboxylic acid. According to the present invention, an aliphatic monocarboxylic acid is understood to mean an acid with a number of carbon atoms of 10 to 26, such as undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, carotic acid, etc. The pigment preparation may also contain a mixture of these acids.

The filler used, the calcium salt of an aliphatic monocarboxylic acid and an aliphatic monocarboxylic acid or a mixture of these acids, have a very positive effect on the dispersion of the pigment in the colored thermoplastic, which leads to the perfect use of the coloring ability of the given pigment, without negatively affecting, for example, the color shade or other coloristic properties.

The preparation of pigment preparations according to the invention can be carried out, for example, by grinding the components in suitable grinding equipment, mixing in homogenizers, etc., both dry and wet. The principle of preparation is therefore the perfect homogenization of all relevant components of the preparation, i.e. pigment, filler, calcium salt of aliphatic monocarboxylic acid and aliphatic monocarboxylic acid.

The pigment preparations according to the invention can be applied for coloring various thermoplastics, e.g. polyethylene, polypropylene, polystyrene, polyvinyl chloride, etc., while always resulting in better dispersion of the pigment in the polymer compared to pure pigment powder.

Coloring of thermoplastics using pigment preparations according to the invention can be carried out, for example, directly at the polymer manufacturer, so that

- 3 229 111 that a pigment preparation is added to the granulate or stabilized polymer powder, either alone or with a certain amount of organic or inorganic pigment to tone down the shade. The mixture is perfectly homogenized and then granulated on a single-screw or twin-screw extruder. The resulting colored granules are colored in the mass and are the starting product for plastics processors. In polyvinyl chloride, the use of a pigment preparation allows direct coloring, i.e. a concentrate does not have to be prepared using the high dispersing effect of the kneader.

Processing into the final product can be carried out on various processing machines, such as injection and extrusion machines, blowing or casting into films, slitting films and stretching into tapes, etc.

The preparation of pigment preparations according to the invention and their application in coloring thermoplastics are illustrated in the following examples.

Example 1

48 g of powdered pigment C.I. Pigment Red 144, 120 g of calcium carbonate, 60 g of palmitic acid and 12 g of calcium stearate were perfectly homogenized in a homogenizer. Homogenization was carried out in a 1.0 liter container for 2 hours. Coloristic evaluation of the pigment preparation was carried out in polyvinyl chloride and in polyethylene (results are given in Table I) against the original red pigment (comparing the coloration with the same pigment content).

' Table I

Polyvinyl chloride Polyethylene Yield 100/100 99.1/100 Shade P.S. P.S. Dispersion hardness 30 5 Migration 5 • - Dispersible in foil particles occasionally 100/um

P.S. ...... practically the same

- 4,229,111

The initial powder pigment had a dispersion hardness in polyethylene of 16, i.e. more than 3 times higher than that of the preparation. Particle clusters of 500 μm in size were found in the film colored with the powder pigment.

Example 2

120 g of phthalocyanine blue (C.I· Pigment Blue 15 ϊ 1), 300 g of precipitated calcium carbonate, 30 g of calcium stearate and 130 g of stearic acid were homogenized on the TURBULA device. The homogeneous mixture was then ground on an ALPÍNE mill at a load of 10%. The pigment preparation thus prepared was used for coloring polypropylene, using the pigment preparation alone (Table II, test No. 1) and the pigment preparation in combination with titanium white (Table II, test No. 2 and No. 3)«

Staining procedure (test no. 2).

Κ I 000 g of granulated polypropylene (homopolymer, melt flow index 2.5 to 4.0 g/10 min, density at 23 °C 0.90 to 0.91 g/cm\ Vicat heat resistance min· 145 °C, yield strength min· 32.0 MPa, Charpy notched toughness min. 2.0 kJ/m ) was added 4.0 g of pigment preparation and the mixture was homogenized for 10 min in a laboratory mixer. Then 0.6 g of titanium white was added and the mixture was homogenized again for 30 min. The homogeneous product was extruded into strands on a laboratory single-screw extruder and the strands were cut into pellets after cooling in a water bath and air. From these, bodies were extruded on an injection molding machine, in which the pigment dispersibility was evaluated visually.

The results of the evaluation of the tests performed are given in Table II. For comparison, a test of coloring with polypropylene and using the pigment C.I. Pigment Blue 15:1 was performed (test no. 4). It is clear from Table II that the dispersibility of the pigment in the test specimens is significantly better when the pigment preparation according to the invention is used than when pure powdered pigment is applied.

Table II 229 111 Exam The approach for Evaluation in c. polypropylene dyeing di apergova eIno stí 1 Pigment preparation 0.5% No visible clumps formed 2 Pigment preparation 0.4% Clump-free dispersion Titanium white 0.6% particles 3 Pigment preparation 0.5% Good dispersion, no particle clumps 4 C.I· Pigment Blue 15 í 1 0.1% Clusters of particles visible on the surface Titanium white 0.6% Dispersant 0.1%

Example 3

A pigment preparation containing 20 wt% of red anthraquinone pigment 0·Ι. Pigment Red 177, 50 wt% of calcium carbonate, 10 wt% of calcium stearate, 30 wt% of stearic acid and 20 wt% of behenic acid was prepared using the pigment preparation. Polypropylene was dyed with the procedure given in Example 2, using the preparation alone, the preparation together with titanium white, and also testing the nuances using the yellow pigments C·!· Pigment Yellow 93 and C.I· Pigment Yellow 110. The results of the evaluation of dispersibility are given in Table III, for comparison the dyeing using pure pigment C.I· Pigment Red 177 (test No. 5) is given.

- 6 Table III

Exam Colorants Evaluation δ* type of quantity (% wt.) dispersibility 1 Pigment preparation Good dispersion, without ₍ (according to example 3) 0.6 clusters of particles 2 Pigment preparation 0.6 Dispersion without Titanium white 0.1 clusters of particles 3 Pigment preparation 0.5 Good dispersion, no Titanium white 0.1 particle clusters, paste- C.IePigment Yellow 110 0.08 yellow shade 4 Pigment preparation 0.5 Good dispersion, no Titanium white 0.1 particle clusters, paste- CelePigment Yellow 93 0.1 yellow shade 5 0»Ι<Pigment Red 177 0.1 Poor dispersion, / clusters of particles

SUBJECT

Claims (3)

. Pigment preparation for coloring plastics, characterized in that it contains 10 to 80% by weight of pigment, 15 to 75% by weight of filler, 1 to 20% by weight of calcium salt of an aliphatic monocarboxylic acid having carbon numbers of 10 to 26 and 5 up to 60% by weight of an aliphatic monocarboxylic acid having a carbon number of 10 to 26 or a mixture of these acids * 2. A pigment preparation as claimed in claim 1, characterized in that it contains an organic and / or inorganic pigment or a mixture of organic pigments as pigment. 3. The pigment preparation of claim 1, wherein the filler is calcium carbonate and / or titanium dioxide.