DE3919236C1 - Compact, millable paint compsn. - contg. binder or water soluble polyethylene glycol and/or polypropylene glycol - Google Patents

Abstract

A compact, millable, paint compsn. consists of (A) known (in)organic coloured pigment(s), (B) 5-55, pref. 10-30, esp. 15-23 wt.% binder being a mixt. of waxy, fatty or oily substances of which at least 30% consists of water soluble polyethylene glycol(s) and/or polypropylene glycol(s) of mol.wt. 300-6,000 or of an organic acid ester with polyethylene glycol or adducts of organic acids with polyethylene oxide. The binder pref. consists to at least 20% of a waxy substance melting above 70 deg. C. Part of the coloured pigment(s) can be replaced by finely divided, inert, inorganic white or colourless fillers. ADVANTAGE - The compsn. has better temp. stability, tinctorial strength and covering powers than known ones and can be produced more simply and cheaply.

Description

The invention relates to a compact, paintable mark medium and a process for its production.

Compact, water-soluble painting medium, for example in Tablet form, are usually called "watercolor paints or watercolors ", where the color such painting means by inorganic or organic Pigments is achieved by using binders such as for example gum arabic, dextrin, gelatin or glue be held together. You can also such painting means depending on the nature of the sub reason for better adhesion also wetting agent beige be mixed (cf. "Römpps Chemie-Lexikon", Vol. 1, page 254, Stuttgart 1979).

The use of gum arabic or dextrin as Binder for watercolor coloring bodies is also also known from DE-PS 6 38 725.

Furthermore, DE 31 48 698 C2 has a paint color Solvents, binders, colorants and given if fillers and / or additives described, in which as a binder cellulose ether, dextrin, carboxyd, Vinyl polymer or polyvienyl alcohol is used, whereby to increase the washability of these known Add different wash-active substances to be mixed.  

The bandage used in these known painting media medium are all from the group of aqueous solution physically drying film formers, d. H., that at the time of compacting, shaping Step the binder must still be dissolved, from which it follows that at this point the whole Material is still relatively damp or wet.

However, this results in the manufacturing process of these known painting means the following, right serious disadvantages:

• a) It takes a very long time (days to weeks) for the wet molding dried out. This makes them relative long manufacturing lead times continue poor flexibility and readiness to deliver, high Space requirements and high capital commitment (business economist disadvantages).
• An acceleration of the drying process, at for example by applying heat or vacuum, is only possible in a very limited and gentle way, otherwise structural defects such as cracks, Ab splinters or weariness can occur.
• b) Another disadvantage is that the hand have still wet moldings because of the high Risk of breakage or deformation is extraordinary is difficult. This also means that the Ent formation with a disproportionate amount of waste count.  
• c) The drying of the moldings is one volume contraction connected. This volume shrinkage is in individual cases from moisture, quality dependent on the raw material batches etc. and not exactly predictable. Because the finished medium tablets Dimensional tolerances, the pre- see oversized cups. As a result the resulting tablets can also don't lie flush in these wells, what on the one hand to an optical flaw and on the other hand leads to a mechanical stability disadvantage.

In addition, one is on the part of the applicant started to produce compact painting mediums in which the color pigments in a relatively large, waxy Amount of binder are distributed, for example in Ver Ratio of 20 wt .-% colorant to 80 wt .-% bandage medium.

The painting medium is therefore initially under appropriate heat application made molten, then inserted into the associated container (cup) pour and finally the solidification of the time waited by means of at room temperature. This from the Applicant's already practiced method indicates particular the following disadvantages:

• a) It is only a relatively low pigment concentration possible. So the resulting Painting medium is good pourable or flowable, the Average solids content in the painting medium limited to a maximum of 30%.  
• The requirements for color strength and opacity most of them can be derived from DIN 5023 Colors do not match.
• b) There is only a limited selection of colored pigments ment possible. Lots of organic color pigments, but also soot, have the property, already in low admixtures the binder melts thicken like mush. This will make a Pour impossible. Organic colors are common pigments also very sensitive to temperature or bleed out.
• The well-known mediums of painting must, however, molten processing stage for Mix / disperse / pour over for hours Melting temperature can be kept, causing it to Color changes are coming.
• Inorganic metal oxide pigments have very high Poetry. They sit down in the melt Pour and cool in higher concentration downwards. The requirements for colors (Sorting, purity, identity) according to DIN 5023 therefore often cannot be fulfilled.
• c) The temperature stability of this known time medium is relatively low. As a result of high binder content and low binding medium melting point (due to temperature sensitivity pigments) change the known ones Pouring colors with increasing temperature very much quickly and clearly. You will soften sticky, bloom or melt itself Temperatures on the room heating or can be reached by sunlight.

The invention is based on the object a painting medium with increased temperature stability, with improved color strength and to provide opacity, and a method that compared to the prior art considerably simplified and cost-saving production guaranteed.

Based on the painting medium of the type defined at the beginning is this object according to the invention by the Merk male of the characterizing part of patent claim 1 solved.

The core idea of the present invention, it will be seen is that as a binder a mixture of wax, grease, or oil-like substances is used, with a minimum of _^3/10 of these substances readily soluble in water (s) polyethylene glycol (s) and / or polypropylene glycol (e ) with molecular weights between 300 and 6000 or esters of an organic acid with polyethylene glycol or poly ethylene oxide adducts of organic acids is used, the proportion of the binder mixture being between 5 and 55% of the basic mass. This provides a base material of the resulting painting medium that is easy to process.

Claims 2-4 relate to others, expedient configurations of the painting medium.

The invention is further based on the object also an improved method of making one to specify compact, paintable painting medium, which for Quality improvement a faster, cheaper and Manufacturing to be carried out with less waste method guaranteed.

This task is characterized by the characteristics of the drawing part of claim 5 solved. Appropriate  Find refinements of the method according to the invention themselves in claims 6 and 7.  

Regarding the incorporation of the Stand the binder mixture in the colorant mixture expediently the following two options Available:

Alternative I: The binder mixture is first in the melted state transferred.

Alternative II: The binder mixture is first in dissolved or emulsified in a liquid, a ver driving step, which is preferred in those cases in Question comes up when relatively lean, i.e. H. low binder Formulations are available.

Whatever the state of the binder mixture, ie either as a binder mixture melt or binder mixture solution or binder mixture emulsion, the subsequent process step of incorporation involves kneading the binder mixture into the colorant mixture prepared first (mixture of pigments, Fillers, this kneading preferably being carried out by means of conventional kneading machines, for example using a Z kneader or a planetary mixer, but optionally also by hand.

Such a kneading process results in more or less viscous mass, which therefore the  from colorant and binder mixture represents the basic mass. This mass is then using larger shear forces homogenize well in the kneading machine.

On the other hand, there is also Possibility to mass homogenize an art extruder with mixing section is used Process step, which is then preferably considered is pulled when the binder mixture in the intermediate stage is present as a solution or emulsion.

Following such homogenization processes the mass is ground to powder or granulated. It there are therefore two different options Alternatives regarding further processing to:

If the mass is made in such a way that a Binder mixture melt into the powdery colorant mixture is kneaded, then homogenizing this mass is, as explained above, then this resulting mass on rolling mills, e.g. B. on one two-stage or three-stage rolling mill, in several Passages are ground. That through such a Intermediate product obtained is then dried so that an appropriate powder is available.

On the other hand, there is also Possibility that, as explained above, kneaded and homogenized mass first well cooled and dried and then with the help of a powder mill, for example with a pin disc mill, to one fine powder is ground.  

If, however, from the second bandage explained above medium alternative is assumed, d. H. if so a binder mixture solution or emulsion of the powdery Colorant mixture is added, then done kneading and homogenizing the mass in a plastic extruder with mixing section, whereby by extreme shear forces for excellent Dispersion of the mass is taken care of. These finely dispersed mass is then used as an intermediate through at least one nozzle, preferably through a given number of arranged parallel to each other Nozzles, d. H. practically through a sieve plate through, pressed out and then cut short, so that a granulate is obtained. That way quasi granulated mass is now before its further Processing well dried.

Which of the above explained Processing alternatives one also selects it is always a resultant, dried one Intermediate either in the form of a powder or obtained a granulate, which then by Dry presses can be compacted to thereby resulting painting medium in the form of a compact To produce shaped body.

The manufacturing method according to the invention offers extremely convenient way that the powder or granules directly in the wells of a paint box can be pressed, whereby to this production run is preferably a normal one Tablet press is used like this from the fields of pharmacy and cosmetics is known.  

The method according to the invention primarily achieved the following benefits:

• - Immediate press fit of the powdered or granulated base (Intermediate product from colorant (s) and Binder mixture) in the respective end Reserves, in particular a well Paint box;
• - No drying shrinkage, so that the moldings always stay close to the container wall and with it in its own right hold;
• - no falling out of the resulting times medium tablets from the well also after repeated use;
• - Avoid the laborious process of gluing the resulting tablets in the wells;
• - Avoid breakage in handling the "bare" tablets;
• - relatively low investment and small space requirement;
• - Availability of commercially available tablets press;  
• - Avoidance of filter systems and thus ver avoidance of filter cake and the er require drying and Ver avoiding the associated disadvantages (Lead time, shrinkage, hair cracks);
• - relatively high proportion of colorant (color pigments and optionally fillers) on the resulting compact painting medium.

Recipe example

As pigments:
15% by weight Blue Col. Ind. No. 74 160
30% by weight titanium dioxide anatase;

as filler:
30% by weight calcium sulfate hydrate from power plant flue gas desulfurization;

as a binder mixture:
10.3% by weight polyethylene glycol (50) stearate
4.5% by weight of stearic acid
2.9% by weight of hard ozokerite
2.3% by weight of polyoxyethylene (20) sorbitan tristearate.

Pigments and filler, which the colorant with a Form a total of 75 wt .-% are in powdered state intimately mixed together. Then the binder mixture with the total proportion of 20% by weight melted and into the colorant mixture, which is preferably heated to about 70 ° C, by means of kneaded in a kneading machine. This in shape A base mixture obtained from a dough is kneaded machine well homogenized, then well cooled and  dried and then fine in a powder mill ground.

The powdery substance thus obtained is then by portionwise pressing under high pressure (over 50 bar) formed into compact solids (dry compact tation), preferably pressing directly into the wells of a color box or painting box to be led.

Claims (7)

1. Compact, paintable painting medium, consisting of inorganic (s) and / or organic (n) color pigment (s), binder and optionally filler, characterized in that the binder consists of a mixture of wax, fat or oil-like substances, wherein at least _^3/10 of these substances well wasserlös Liche (s) polyethylene glycol (s) and / or polypropylene glycol (s) are having molecular weights of 300-6000 or an organic acid ester with poly ethylene glycol or polyethylene oxide adducts of organic acids and The proportion of the binding agent mixture is between 5 and 55% by weight of the basic mass. 2. Painting medium according to claim 1, characterized, that the proportion of the binder mixture is between 10 and 30% by weight, in particular between 15 and 23% by weight the basic mass. 3. mediums according to claim 1 or 2, characterized in that the binder mixture comprises at least _^2/10 consists of waxy substances having a melting point of over 70 ° C. 4. Painting medium according to one of claims 1-3, characterized, that part of the color pigment (s) by fine partial, inert inorganic fillers, which are either colorless or white. 5. A process for the preparation of a painting medium according to claims 1-4, characterized in that in a manner known per se

• a) at least one finely powdered inorganic and / or organic color pigment and, if appropriate, filler (s) intimately mixed with one another;
• b) a binder mixture according to claim 1 is roughly uniformly incorporated into the mixture obtained in a), the binder mixture being either melted or dissolved or emulsified in a liquid beforehand and then homogenized well;
• c) the homogenized mass according to b) either
  • i) first cools and dries well and then pulverizes or
  • ii) first pulverized or granulated and then drying and
• d) the dried powder or granules are then compacted by dry pressing, if necessary directly into empty cells.

6. The method according to claim 5, characterized, that to dissolve or emulsify the binding agent mixed amounts of liquid can be selected, which between 15 and 35% by weight of the resulting Color pigment (s) and binder existing reason mass. 7. The method according to any one of claims 5-6, characterized, that obtained according to claim 5, feature a) Mixture is warmed up to approx. 70 ° C at the same time.