FR2460311A1 - Solid colourant concentrate for thermoplastic resins - contg. mineral diluent, additives and low viscosity thermo-fusible binder - Google Patents

Abstract

A solid colourant concentrate comprises a colourant system, a mineral diluent and additives dispersed in a thermofusible binder of low viscosity and compatible with the usual thermoplastic resins. The colourant system may comprise insoluble (in)organic or metallic pigments or soluble colourants. The binder pref. comprises 50-85% resin of mol. wt. less than 2500, 0-10% linear plasticiser, 10-25% a surface active, solid plasticiser, 5-25% reinforcing polymer and balance additives. The concentrate can be rapidly and simply prepd. with lower energy expenditure than in prior art. It can be used with conventional thermoplastic resins (i.e. polyolefins, polystyrenes, vinyl resins, polyurethane, polyamide etc.). It can be formed into non staining granules or powder and is adaptable to conventional processing (injection, extrusion etc.).

Description

 The present invention relates to the technique of coloring plastic materials and more particularly to a new technique for preparing solid coloring concentrates.

 It is already known that the thermoplastics used by injection - extrusion - extrusion blow molding - calendering, etc. are colored by different processes t the pre-colored resin or bulk coloring - coloring by means of solid coloring concentrates also called master mixes - coloring using liquid coloring concentrates - dry coloring.

Each of these processes has its qualities and faults and therefore attracts the following remarks regarding their production method and their use.
The precoloured resin or mass coloring represents in all respects the heaviest system, at the production level as well as at the transformer level. This system is very expensive in terms of material investment and energy expenditure in production, in storage costs at the transformer. This solution is only favorable for users of one or a minimum of grades.

 Coloring by means of attractant mixtures represents a decisive progress. If the investment is at least equivalent, the quantity of material transformed per objective is much lower, hence better productivity and energy saving. The appearance of the universal marten mixture, that is to say compatible with several different thermoplastic materials, is recent. This solution brings new advantages of flexibility in production. It allows the processor to improve its inventory management, it eliminates the possibility of errors and makes the products in stock always available.

 The coloring concentrate is in physical form close to the colorless granule.

 The usual rates vary from 0.5 to 2% and up to 3% in the film industry.

 The dosing of the threshing mixture is carried out either by premixing in a barrel for small productions, or by means of an automatic doser placed on the processing machine. The use of a dispenser simplifies the coloring operation. It is economical in terms of space and labor.

It always requires the intervention of a specialist adjuster, it adapts better to manufacturing of some importance.

It must always coexist with the barrel coloring system whose flexibility and reliability are second to none.

The use of dosing devices is in full development with the appearance of more and more competitive models.

 This technique has a very average flexibility because it always forces the transformer to orders large enough to obtain non-standard grades.

Coloring by means of liquid coloring concentrate has also appeared recently. The interest of this technique is based on a universal liquid formulation combined with a convenient, simple and economical dosing means.

 The means of production fall under those used in the manufacture of paints, inks, etc ...

 The coloring obtained is very good, the process adapts perfectly to certain continuous productions preferably. The process is not without its faults, it comes up on the psychological level with the reluctance of the transformers to use and handle liquid products alongside and at the same time as granulated solid products. On the technical level, various problems remain, specific to the paste form, for example t problems of dosage, stability of the suspensions, ect ...

 Dry coloring is the simplest process.

It essentially consists of depositing a powdered coloring mixture on the surface of the granules by premixing in a barrel.

Given its relative simplicity, it is also the most economical.

The results obtained in terms of coloring are generally acceptable, it nevertheless remains that certain pigment mixtures always give results which are very inferior in quality, despite the lubricant adjuvants used.

This solution is the most flexible to start new manufacturing, but also the most polluting and therefore the least appreciated by processors and their staff.

 There are also dispensers capable of using these products. Pollution risks still exist, at all stages of implementation.

 It has now been found that it is still possible to improve the traditional systems, to overcome some of their drawbacks and to obtain a very high quality of coloring by the ease of using a non-simple and rapid process requiring only a simplified apparatus. Manufacturing.

The process relates more particularly to the production of a solid coloring concentrate in a hot-melt binder of great fluidity. The coloring phase is dispersed by the use of a mixer-disperser with high mechanical and hydraulic shearing power.

The process also makes it possible - To produce solid coloring concentrates for an investment in equipment and an energy expenditure much lower than traditional methods.

- To produce these concentrates quickly and simply - To offer universal coloring concentrates, that is to say compatible with the usual thermoplastic resins - polyolefins and copolymers - styrenates, copolymers and alloys - vinyl resins - acrylics - urethane - polyamides, etc ...

- To be able to be in the form of granules or non-staining powder, after grinding the granules, to adapt to all the requirements of the processors.

- To offer the benefit of this clean and efficient presentation even for medium or small needs.

- To produce a product that meets the needs and habits of current processing techniques (injection, extrusion, blow molding, calendering, etc.)
More specifically, the solid coloring concentrate comprises; - A hot-melt binder - A pigment system - A mineral diluent - Additives or adjuvants
The hot-melt binder uses for its formulation: 10 / - A resin of polydiene - cycloaliphatic saturated polyterpenic - polyterpenic phenol - alkyl aromatic type.

These resins are of molecular weight less than 2500 and capable of withstanding without degradation the temperatures of implementation of the various transformation processes.

They are used alone or as a mixture to combine their qualities and maintain the best wetting properties and transport capacity of the pigments.

The resin or mixture of resins then has a softening point of 85 to 1250C.

These resins are chosen from those of so-called "food" quality, that is to say approved by legislation and therefore able to be brought into contact with foodstuffs.

20 / - A linear plasticizer - of aliphatic and naphthenic type, example: paraffin oil, paraffin and higher terms oxidized or not - of fatty acid monoester type, example stearate, octyl epoxystearate, cetyl palmitate and sterarte, monostearate ethylene glycol - diester type of linear dicarboxylic acids, example t 2-ethylhexyl adipate, etc ...

The plasticizers are chosen from those of so-called "food" quality and used alone or as a mixture to obtain the best efficiency.

Other plasticizers can also be used to respond to and adapt to any particular problem, for example phthalates - phosphates - polyesters - polymeric plasticizers.

Example: all problems relating to the use of polyvinyl chloride in the broad context of its formulations, its various processing means and its numerous applications.

30 / - A solid surfactant plasticizer capable of the following actions - Lubricating action - Surfactant action to improve wetting power and
medium dispersant - Depressive action on viscosity
Among the products responding more or less intensely to the above actions, and satisfying the problem, are the solid esters of saturated fatty acids and of polyol of the glycerol, pentaerythritol and sorbitol type. These include in particular monolaurate, monopalmitate, glycerol or sorbitan monostearate, polyoxyethylene sorbitan tristearate, glycerol mono 12 hydroxystearate, pentaerythritol monostearate.

They can be used alone or in combination. They are chosen from so-called 'food' quality products 40 / - A reinforcing polymer
This base brings to the formula cohesion and tenacity. The ethylene-vinyl acetate copolymers are excellent for this role. Their amorphous structure makes them compatible with many polymers.

 Suitable copolymers contain 14 to 28% vinyl acetate.

In general, the binder p @ ut @ includes the following propulsion intervals: 50 to 100% - 0 to 10% of plasticizer - 10 to 25% of tonsioactive plasticizer - 5 to 25% of polymer romferçomt
Its melting point is less than 120 C. The average viscosity of the binder at 140 C varies from 300 to 700 @ps. By the choice of resins and the rate of polymer containing one can thin or thicken the binder within reasonable limits so that there remains miso it is easily covered by means of a mixer-disperser.

The preparation of the liaut takes place in a tank heated by a double jacket with oil circulation. The preparation and storage temperature is around 140 ° C.

With continuous stirring, after melting the most meltable products, the resins and the adjuvants are introduced, and the reinforcing polymer is terminated. This mixture is kept in an insulated tank, closed with a low calorific contribution. it is available instantly for any preparation0
The pigment system uses - Mineral pigment dyes, the rate of incorporation of which
tion varies from 40 to 75%. Of the additional part to 100 repres
therefore smells the binder - Organic pigment dyes, incorporation rate goes
reliable, maximum 30% - Soluble dyes - Black pigment dyes - incorporation rate of 8
at 70% - Metallic pigments - incorporation rate from 30 to 85%
Mineral thinner
These products come in fine particles with dimensions between 0.2 and 15 microns, depending on the objective.

The shapes can be spherical, heterogeneous, lamellar, acicular, the oil intake weak or quite significant. The uptake of oil corresponds to the demand for a pigment binder and allows you to assess its specific surface. These products can be treated on the surface, which then makes them hydrophobic and therefore very easily dispersible. they are perfectly known and used in a number of important techniques.

 Let us quote the wide range of calcium carbonates - barium sulphate - magnesium silicate - silica, etc ...

These products are often called mineral thinners because their properties are essential in formulations.

 In this case, they play the important role of rheology checker thanks to their thermal and pigmentary inertia. For a determined quantity of pigments, calculated to obtain a shade, the mineral diluents therefore make it possible to limit the level of binder, with a view to obtaining a paste of suitable consistency. This is determined quite empirically, since there is no difficulty of the sedimentation separation and narrow viscosity limits type.

 The suitable consistency is appreciated by surface characteristics corresponding to a dough which is not very runny, but which remains easy to handle. For special applications, whores of higher viscosity can also be produced.

Additives or adjuvants
They can be used in small or very large doses, depending on whether their choice or their action relates to the coloring concentrate, the thermoplastic material or both. Therefore, from the hot-melt binder, all the other elements of the formulation can be easily varied.

 We can therefore carry or transport only a pigment, a filler - an additive - or all the intermediate variations which remain infinite.

 Among the additives or adjuvants, let us mention the lubricants: slip agents - antistatic agents - antioxidants - flame retardants UV absorbers - porophores - agents of bio or photo degradation opacifying of radiation, etc ...

 The preparation of the coloring concentrate uses a high speed dispersing mixer, fitted with a cowles type turbine or stator rotor.

The mixing tank is cylindrical, with a flat bottom, and heated to around 1500C.

 After introduction of the binder - around 1400C - the turbine is lowered near the bottom of the tank and with moderate stirring the pigments are introduced, starting with the lightest. Between each relatively large contribution, there is a dead time to allow the turbine to absorb this work.

 At the same time, the speed of the turbine is increased resistance - - - -. to defeat the couple! due to the pigment paste. at the end of introduction, the turbine is slightly raised and brought to its maximum speed. We then observe a powerful vortex movement of the dough. The kinetic energy of the turbine causes extremely high mechanical and hydraulic shears, as well as self-heating corresponding to the dissipation of energy.

This intense work therefore explains the rapidity of the wetting and dispersion phenomena, further facilitated by the processing temperature which dehydrates the pigments practically instantly.

 Dispersion problems can be easily modulated if necessary, depending on the pigments, using an intermediate preparation which facilitates dosage and formulations. The already high production speed thereby gains in quality, ease, and even speed.

 After 5 to 10 minutes of dispersion, the mineral diluent is introduced. The corresponding thickening slows the movement of the dough and the action of the turbine. This then becomes active, by attacking all the points of the tank by an up and down movement back and forth. After two minutes of additional dispersion, the preparation is finished. The dough is extracted by tilting or by pneumatic pushing. It is collected between cold cylinders, calibrated in thickness of 3 mm, placed on a carpet towards the granulation.

 Generally speaking, for a turbine diameter D, the tank has a diameter of 2 to 2.5 D, to allow intensive and rapid work.

 The peripheral speed of the turbine must reach at least 1500 m / min, With a tank diameter of 60 cm useful height 60 cm - the production of 200 kg of white coloring concentrate requires less than 30 minutes.

 The 11 KW power disperser mixer uses a 30 cm diameter turbine. Fueled by a series of tanks of different diameters, serving a granulation draw unit, a single disperser mixer equipped with the corresponding turbines allows a significant level of production to be achieved. This level can be doubled by simply installing a second granulation pulling unit.

 The optimization of the means of production can also easily be achieved, thanks to the flexibility of the equipment used and the basic technology. Finally, it is important to point out that these objectives are also achieved using simple, reliable, very economical equipment, compared to traditional equipment and technology.

 Finally, the polycompatible binder can also be used, in liquid form or in granular form, on traditional equipment such as a mixer, a single screw or multiple screw mixer.

 It is thus possible to produce products with a high pigment concentration, significant continuous manufacturing and, more generally, to respond to any problems posed by exploiting all the resources of this technology.

 In order to color according to the invention, 100 kg of plastic material in granules, such as polyethylene HP or BP, polypropylene, polystyrene crystal or shock, a polyamide, etc. 1 to 2 ffi of the coloring concentrates were used defined in examples 1 to 8.

 Example 6 was used only for coloring the polyethylene HP. The pieces obtained had a perfectly uniform coloring, without mottling or veining.

Here are some typical and non-limiting examples of coloring concentrates according to the present invention
Example 1
Ti 02 60
Barium sulfate 15
Polydiene resin 16.25
Sorbitan monostearate 4.25
Paraffin oil 2.25
Ethylene - vinyl acetate 1.75
Oleylamide 0.5
100
Example 2
Ti 02 70
Polydiene resin 16.20
Glycerol monostearate 8.1
Paraffin wax 2.1
ethylene - vinyl acetate 3
Zinc stearate 0.6
100
Example 3
Ti 02 60
Cycloaliphatic resin 26
Paraffin oil 3.2
Sorbitan monostearate 4
Glycerol monostearate 4
Ethylene - vinyl acetate 2
Zinc stearate 0.8
100
Example 4
Phthalocyanine blue 30
Polydiene resin 24.5
Polyterpene-phenol resin 24.5
Glycerol monostearate 11.9
Paraffin oil 4.9
Ethylene - vinyl acetate 2.8
Zinc stearate 1.4
100
Example 5
Quinacridone red 20
Calcium carbonate 30
Polydiene resin 33
Octyl adipate 3.5
Glycerol monostearate 10
Ethylene vinyl acetate 2.5
Zinc stearate 1
100
Example 6
Molybdenum orange 70
Polydiene resin 19.8
Glycerol monostearate 6
Octyl adipate 2.1
Ethylene - vinyl acetate 1.5
Zinc stearate ~ o, 6
100
Example 7
Ti 02 50
Magnesium silicate 20
Polydiene resin 18
Glycerol monostearate 6
Paraffin oil 1.5
Ethylene vinyl acetate Oleylamide 0s45
100
Example 8
Ti 02 50
Calcium carbonate 25
Pelydiene resin 15
Glycerol monostearate 3.75
Paraffin 2.5
Ethylene - vinyl acetate 3b25
Zinc stearate 0.5
100

Claims (6)

CLAIMS 10 / - Solid coloring concentrate characterized in that it essentially comprises a coloring system, a mineral diluent, additives or adjuvants dispersed in a hot-melt binder of low viscosity and polycompatible with the usual thermoplastic resins. 20 / - Solid coloring concentrate characterized according to claim 1 in that the coloring system can be based on organic pigment pigments - inorganic - metallic insoluble soluble dyes 30 / - Solid coloring concentrate characterized according to claim 1, in that it comprises a hot-melt, polycompatible binder, with a melting point less than or equal to 120 C, having at 1400C an average viscosity between 300 and 700 cps and comprising 1 - A resin of molecular weight equal to less than 2500 2 - A linear plasticizer 3 - A solid surfactant plasticizer 4 - A reinforcing polymer 5 - Additives or adjuvants 4 / - Solid coloring concentrate characterized, according to claims 1 and 3, in that the resin or the mixture of resins, of molecular weight less than or equal to 2500, has a softening point of 85 to 1250C and can be of the following types: polydiene, saturated cycloaliphatic, polyterpenic - polyterpene phenol - aromatic alkyl. It must have excellent thermal resistance corresponding to the conditions of use of the thermoplastics. - - Solid coloring concentrate characterized, according to claim 3, in that the linear plasticizer can be of the aliphatic, naphthenic solid or liquid type, for example: paraffin oil, paraffin and higher terms oxidized or not - of monoester type fatty acid, example: octyl stearate, epoxy dtoctyl stearate, of the diester type of dicarboxylic acids. Example 2 ethyl hexyl adipate. The boiling point must be above 2000C under an absolute pressure of 5 mm of mercury. 60 / - Solid coloring concentrate characterized according to claim 3 in that it comprises a solid surfactant plasticizer chosen from monoesters of fatty acids of glycerol, sorbitol, erythritol, glycerol tristearate, sorbiten polyoxyethylene tristearate, mono 12 glycerol hydrostearate, They can be used alone or in combination 70 / - Solid dye concentrate characterized, according to claim 3 in that it comprises a reinforcing polymer selected from ethylene-vinyl acetate copolymers. Suitable polymers contain 14 to 28% vinyl acetate. 80 / - Solid coloring concentrate characterized, according to claims 1 and 3, in that the constituents of the hot-melt binder are present in the following proportions:  Resin 50 to 85%  Plasticizer 0 to 10%  Solid plasticizer 10 to 25%  surfactant Polymer reinforcing 5 to 25%  Additives -Q S 90 / - Solid dye concentrate characterized, according to claim 1 in that the mineral diluent allows hot rheology to be adjusted by limiting the level of binder. It can be selected from carbonates, sulfates, alkaline earth silicates, silica. It has an average particle size between 0.2 and 15 microns. The oil uptake can be low to high 100 / - Solid dye concentrate characterized, according to claims 1, 3 and 9, in that the dye system can be accompanied or totally replaced by any additive or adjuvant depending on whether their action relates to the coloring concentrate, the plastic or both. Nonlimiting examples: lubricants - slippery - antistatic - antioxidants - flame retardants - absorber UV - pore-forming agents - bio or photodegradation agents - various mineral charges - metallic charges - anti-radiation charges. 110 / - Solid dye concentrate characterized, according to claims 1 and 3, in that the low hot viscosity of the polycompatible binder allows the dispersion of all the elements of the formulation at a temperature below 1600C using suitable mixer-dispersers the conditions of implementation and the viscosity of the medium. Mention may be made, for example, of turbines of the "flow" type and of the ntrèflen type for use at low and high speed. 120 / - Solid coloring concentrate characterized, according to claims 1 and 3, in that the use of the polycompatible binder in liquid form or granules with the other elements of the formulation, can also be carried out on a mixer, a single-screw or continuous mixer several screws. 130 / - Any article characterized, in that it is constituted at least in part with the aid of a plastic material in which a concentrate corresponding to one of the preceding claims has been incorporated.