GB2029838A

GB2029838A - Pigment Preparations for Plastics

Info

Publication number: GB2029838A
Application number: GB7926175A
Authority: GB
Original assignee: COLORPLAST DOEBELN VEB
Current assignee: COLORPLAST DOEBELN VEB
Priority date: 1978-07-28
Filing date: 1979-07-27
Publication date: 1980-03-26
Also published as: DE2925013A1; DD137843A1

Abstract

A colouring agent preparation for colouring plastics materials, consists of colouring agents and a carrier material, which is a metal soap, hard paraffin or polyethylene wax. Antistatic agents, antioxidants and blowing agents may be incorporated in the preparation.

Description

SPECIFICATION Colouring Agents for Plastic Materials This invention relates to a colouring agent composition for colouring plastics foils, plastics materials, moulded articles, hollow articles or the like, in bulk, and a method of production thereof.

Colouring agent preparations, pigment preparations, pigment dressings or the like, are used for the colouring of plastics materials.

These are generally in paste form, as powders or granulates. Solid granulated pigment preparations are preferred as so called master batches. The colouring pigments or other agents are bonded on a carrier material which should as far as possible be identical with the plastics material to be coloured, or otherwise should not alter its properties too much in an undesirable manner.

For this reason a large number of different compositions of the master batches or similar colouring agent preparations are known. What is decisive for the amount of colouring agent preparation to be used is the greater or smaller proportion of colouring agent in the preparation.

In order to reach a colour proportion of 5% for example in the end product, up to 30% of colouring agent preparation must be added, depending on the proportion of pigment in the preparation. Various raw materials for the production of plastics materials are used as carrier material or binding agents for the colouring agents, for example organic polymers (DE-OS 2427952), polyolefins (DE-OS 2259978), polyester (DD-PS 105248), resins, formed by mixing formaldehyde with arylsulphonamide (DE AS 2608864 and DD-PS 128940).

Because of the carrier material, these preparations generally cannot be used universally and are only suitable for special plastics materials or otherwise alter the thermal or mechanical properties, more or less negatively according to the amount used in the plastics material.

The manufacturer of the end products therefore requires a large number of different master batches, even for the same colour according to the differant raw materials.

Colouring agent preparations with a pigment proportion up to 90% by mass are known, where the pigment dispersion consists of pigments coated with fatty acid amide in particle form (DE OS 221 5871). For this and other preparations (DE-OS 2600211,2536719, 2244777, 2427952) a complex apparatus and devices as well as the considerable energy is needed for production. Moreover, the throughput in relation to production area and unit of time is reiatively low because of the reaction time and/or dissolving time needed. On the other hand, mechanical dispersion methods generally only result in low colour concentrations.

This invention seeks to provide highly concentrated colouring agents from any desired colouring agents in solid form, in which the additives necessary in the after processing can be incorporated at the same time. These colouring agent preparations should be usable for all types of polypropylene, polystyrenes, hard and soft PVC and polyamides PUR and polycarbonates, without altering the properites of the moulding compositions to be coloured in an undesirable manner.

The invention provides colouring agent preparations of high concentration with a carrier material which at the same time fulfils the function of a lubricant and mould release agent in the production of the end products.

A further object of the invention is to render possible the production of the colouring agent preparations according to the invention by means of a simple low-energy requirement process.

According to the invention there is provided a colouring agent preparation for colouring plastics materials, consisting of colouring agents and a carrier material, wherein metal soaps, hard paraffin or wax is used as carrier materials for the colouring agent and the proportion of pigment amounts to 60 to 80% by mass. Antistatic agents, anti-oxidants and blowing agents may be incorporated. The proportion of colouring agent preferably amounts to 40 to 80% by mass.

The metal soaps, preferably Zn-stearate or Alstearate, which have a satisfactory wetting and dispersing capacity, show the best result with regard to colour distribution. The extremely fine powdered structure provides satisfactory prerequisites for a uniform distribution of the colouring agent in the preparation.

The preparations according to the invention will be explained in more detail below with reference to examples.

Example 1 Colouring agent preparation in white 80% white pigments 20% metal soap Example II Colouring agent preparation in white 60% white pigments 40% polyethylene wax Mixtures with 2% and 5% in high pressure and low pressure polyethylene were produced from these preparations I and II and used for coating paper.

The results of the experiment reads: "The quality with regard to the density and distribution in the PE is excellent." Paper foil produced with this white concentrate in a thickness of 1 5 MY showed an excellent quality without the formation of specks or streaks.

Example Ill 70% colouring agent (organic and/or inorganic)

20% UV stabilizer at the same time 6.5% metal soap } binding agent and meta soap . and pigment carrier 3.5% antistatic agent If 1.428 kg of this preparation are added to 100 kg, 1.000% colouring agent 0.285% stabilizer 0.093% metal soap are contained in the end product.

Since no additional carrier material is included, this preparation can be used generally.

Example IV 80% pigments, selectively, blue, red or yellow 20% stearate With an addition of 0.5% of colouring agent concentrate to polypropylene, 0.4% pigments and 0.190% stearate are contained in the end product. The yarn spools prepared with this, which are exposed to heavy loading and otherwise crack at the flow seams, no longer crack after colouring with the concentrate given.

Example V Recipe with blowing agents 50% colouring agent (organic and/or inorganic) 30% hard paraffin, metal soap or wax 20% blowing agent In this case the proportion of blowing agents and pigments corresponds precisely to the amount needed to achieve the desired colouring effect required in the end product.

In the production of these colouring agent preparations it has been found that the mixing of the colouring agent components and hard paraffin, metal soap or wax is of significance in determining the quality of the preparation.

The method of production thus developed is characterised by the following features: 1. The metal soap or hard paraffin is introduced into a rapid mixer while in the rest position and the lid fastened down.

2. After starting the mixer the colouring agents are fed in small quantities through a sluice into the ensuing powder vortex. This causes the colour particles to be well rinsed by the pulverulent carrier particles.

3. The mixing process is carried out untilthe mixture has a consistency enabling it to flow without mechanical aids.

4. The mixed material is heated in an extruder without building up pressure to the melting point of the particular carrier material, whereby the carrier particles melt between the colour particles, encapsulate these and prevent the formation of an agglomerate.

5. The molten, hot, paste-like colouring agent preparation flows out of the extruder and onto a conveyor belt where it cools and drops through a funnel into a friction mill.

6. After the grinding process the ground material is separated into three different grain sizes, which can be used for specific colourings or shades of colouring.

The advantages of the solution according to the invention is that it is possible, with the same effectiveness, to reduce the material used by the manufacturer of the colouring agent preparation and so to save transport costs, space and electrical energy.

The pigment distribution is particularly good in the colour preparations produced in accordance with the proposed compositions, which has an effect on higher density and improved colouring effect in the coloured moulding compositions.

With less colouring agent added to the moulding compositions when colouring with the colouring agent preparations according to the invention, the same density and the same colouring effect as before is achieved and so is a saving in colouring agent.

A further advantage consists in that these preparations render possible, for the first time, use in foils, paper foils and polypropylene.

Hitherto, the colouring firms had to use the appropriate master batches for each kind of moulding composition (plastics material) used.

Moulding compositions of polyethylene, polypropylene, polystyrene, polyvinyich loride, polyamides and polycarbonates can be coloured with the above preparations. This means a simplification in storage for these firms.

It is a further advantage that through the use of lower temperatures in the production of the preparations, the necessary additives such as antistatic agents, antioxidants and blowing agents can be incorporated, as a result of which additional operations of later admixture during further processing are eliminated. A further advantage consists in that the addition of lubricants to improve the flow capacity of the moulding compositions in the screw press or blowing installation during further processing is eliminated.

Claims

1. A colouring agent preparation for colouring plastics materials, consisting of colouring agents and a carrier material. wherein metal soaps, hard paraffin or wax is used as carrier materials for the colouring agent and the proportion of pigment amounts to 60 to 80% by mass.

2. A colouring agent preparation as claimed in Claim 1, wherein the composition consists of: 60 to 80% colouring agent and 20 to 40% metal soap and/or polyethylene wax.

3. A colouring agent preparation as claimed in Claim 1, wherein the composition is: 40 to 70% colouring agent (organic and/or inorganic)

6.5 to 40% metal soap and/or hard paraffin 20% UV stabilizer and/or blowing agent and selectively

3.5% antistatic agent and/or anti-oxidant.

4. A colouring agent preparation as claimed in any one of Claims 1 to 4, wherein Zn-stearate or Al-stearate is used as metal soap.

5. A method of producing a colouring agent preparation as claimed in any one of Claims 1 to 4, wherein the carrier material is poured into a stationary high-speed mixer and with the mixer running the colouring agents are added gradually, and the mixed material which is capable of flowing is melted in an extruder without pressure and the composition, after cooling on a conveyor belt, comminuted in a friction mill.

6. A colouring agent preparation as herein described and exemplified.

7. A method for manufacture of a colouring agent preparation carried out substantially as herein described and exemplified.