CS201720B1 - Method of preparation of the microheterogenous systems emulsions - dispersions or suspensions with increased water retardation - Google Patents

Description

suspension - with increased water retardation

The invention relates to a process for the preparation of micro-heterogeneous systems - emulsions, dispersions or suspensions - with increased water retardation.

To date, a number of methods of water retardation in micro-heterogeneous systems, based on the addition of hydrated substances such as tragacanth, vegetable gums, glutin, colloidal silicon dioxide, cellulose derivatives, polyvinyl alcohol solutions, swellable polyesters, polyvinyl ethers or other substances generally used as thickening or emulsifying agents for emulsions and dispersions. Disadvantages of these substances are, inter alia, reversibility of residues, instability, low resistance to microorganisms, decomposition oxidation or relatively low water retardation.

These disadvantages can be overcome by the method of the invention.

The nature of the disadvantage can be overcome by the method according to the invention.

The principle of this process for the preparation of micro-heterogeneous systems - emulsions, dispersions or suspensions - with increased water retardation is that synthetic polymers or copolymers of alpha, beta-unsaturated carboxylic acids and their esters selected from the group consisting of esters with aliphatic polyhydroxy compounds of the alkylene glycol type wherein the alkylene has 2 to 6 carbon atoms, polyether derivatives thereof, e.g. N, N-disubstituted with alkyl of up to 6 carbon atoms, which alkyl may be further substituted with a hydroxyl or amino group at any position, aminoalkyl esters of alkyl of 1-6 carbon atoms, e.g. 2-aminoethyl methacrylate, wherein the amino group may additionally be N -monosubstituted or Ν, Ν-disubstituted by alkyl of up to six carbon atoms, prepare aqueous colloidal solutions, and these are ionically crosslinked by the action of ions of elements selected from aluminum, magnesium, tin, chromium, molybdenum, cobalt, iron, zinc, nickel, copper, lead, antimony, bismuth, manganese, mercury, cadmium and silicon, phosphorus and boron are converted into highly hydrated gels with completely or only partially insoluble residue.

When a polymeric material containing amino groups, singly or substituted, is used in the preparation of the microheterogeneous system of the invention, these crosslink using polyfunctional low molecular weight carboxylic acids selected from the group consisting of tartaric, citric, oxalic, or ammonium salts thereof. When a polymeric material containing a free amino or hydroxyl group is used, it crosslinks using aldehydes such as formaldehyde, glutaraldehyde and / or diisocyanate. In addition, other ingredients such as plasticizers, solvents, fillers and pH adjusters may be added to the resulting products.

By using the micro-heterogeneous systems prepared by the method according to the invention, the above-mentioned drawbacks are fully eliminated and, in addition, the materials prepared in this way allow to directly set the desired properties of the prepared composite materials. A further advantage of the microheterogeneous systems using the compounds of the invention is that the water evaporation time of the microheterogeneous system to which they have been added is considerably prolonged, the system not being diluted with water but replaced with a water-retaining dispersion. The resulting irreversible residues are colorless, non-yellow, sufficiently strong and elastic and have good adhesion to the substrate. These substances are not attacked by micro-organisms, the consumption of raw materials is low and they can also be waste substances from domestic production companies.

Water retardation in micro-heterogeneous systems - emulsions, dispersions or suspensions - prepared according to the invention is achieved by using highly hydrated gels prepared on the basis of synthetic polymers or copolymers of alpha, beta, -unsaturated carboxylic acids and their derivatives, which are: esters with polyhydric alcohols of the glycol type polyglycols, glycerol, carbohydrates of the pentose or hexose type and polysaccharides of the dextrin or starch type, or other polyhydroxy compounds; amides of such acids, such as acrylamide, methacrylamide, which may be N-monosubstituted or Ν, Ν-disubstituted by alkyl of up to six carbon atoms, which alkyl may be further substituted by a hydroxyl group or an amino group at any position; aminoalkyl esters such as 2-aminoethyl methacrylate, wherein the amino group may further be N-monosubstituted or Ν, Ν-disubstituted with alkyl of up to six carbon atoms, such as N, N-dimethy 1-2-aminomethacrylate.

As alpha, beta-unsaturated carboxylic acids, for example, acrylic, methacrylic, itaconic, citraconic, maleic, fumaric, or their anhydrides, halides or alkyl or ammonium salts can be used. The above polymeric materials can be prepared according to known procedures described in the disclosures of U.S. Pat. U.S. Patent Nos. 141101; 166553; further in the descriptions of inventions to Czechoslovak. author's certificate No. 153765; 154962; 154466; 185007; 185008,

In the process according to the invention, aqueous colloidal solutions are prepared from the abovementioned polymeric substances and these are converted by ionic or covalent cross-linking into gels with a completely or only partially insoluble residue. The resulting product is converted into its own micro-heterogeneous system by known dispersing methods, which is further used as a retarding agent for dispersions which are intended to increase the water retention and thus to increase the drying time of their residues. By way of example, an extension of the drying time of latex paints and the like, where specifically required.

The ionic crosslinking of the above substances in an aqueous environment depends on the dissociation degree of the coagulator and the quality and content of the electronegative or electropositive substitution groups in the polymer matrix. For these reasons, it is apparent that different behaviors are exhibited, for example, by carboxyls, hydroxyls or amino groups, and very complicated compounds can be formed with various types of bonds. According to the invention, the ions of the following elements are preferably used as coagulator: aluminum, magnesium, tin, chromium, molybdenum, cobalt, iron, zinc, nickel, copper, lead, antimony, bismuth, manganese, mercury, cadmium and silicon, phosphorus and boron .

If the starting polymeric substances contain alkali salts of carboxylic acids when transferred to an aqueous solution, they must be converted to the corresponding ammonium salt in order to eliminate the interfering effect of undesired strongly dissociated electrolytes on the stability of the micro-heterogeneous system to which they are added. This prevents unwanted coagulation or disintegration of the emulsion, dispersion or suspension.

When the polymeric material contains amino groups, either singly or substituted, polyfunctional low molecular weight carboxylic acids or their ammonium salts, such as tartaric, citric, oxalic, can be used for crosslinking. If the polymeric material contains a free amino or hydroxyl group, aldehydes such as formaldehyde, glutaraldehyde and / or diisocyanate may also be used for crosslinking. In cases where the polymer matrix contains both carboxyls and amino groups, optionally substituted, intra- and intermolecular interactions can advantageously be used for cross-linking, but they only take place in a certain pH range. This cross-linking area can be extended by the use of a suitable cation, e.g., aluminum ions.

It is also possible to control the formation of the desired properties of the gels as well as the properties of the heterogeneous array by the process of the invention. It can be achieved that the resulting product has the desired properties, such as stability to the addition of electrolytes, insolubility of the residue, limited swelling in water, proportional density and viscosity.

The product obtained can be further treated with various additives such as plasticizers, fillers, buffers, etc. The additional retardants according to the invention have a wide application in the coating technique, for example in paints on a blotting substrate, in artistic painting where they reduce the hardness of the tempera , with the assistance of suitable fillers, such as cellulose derivatives (e.g. methylcellulose), they may mimic a plastic brush stroke similar to a pasty oil paint, etc. When a pre-pasted pigment is added to the dispersion according to the invention, eg ochers, veral yellow, phthalocyanine blue or green, alizarin lacquers, etc., an acrylic dispersion tempera is formed.

The following examples serve to illustrate the invention, but do not limit the scope thereof in the listing of substances and combinations thereof.

Example 1

100 g of a copolymer of (2-hydroxyethyl) methacrylate and methacrylic acid in a molar ratio of 50:50 mole%, prepared according to U.S. Pat. No. 154466 is suspended in 1500 ml of water and 100 ml of an aqueous 10% ammonium hydroxide solution are added. A water-soluble ammonium salt is formed. To this solution is added 500 ml of a 10% pre-treated poly (vinyl alcohol) solution. The pretreatment of poly (vinyl alcohol) is carried out by carefully dropping 10% sodium tetraborate solution with vigorous stirring (only a few ml of tetraborate solution is sufficient for 500 ml poly (vinyl alcohol) solution) until the solution of poly (vinyl alcohol) is passed in a thick gel. In this way, the poly (vinyl alcohol) solution is not only thickened, but also undergoes a chemical change, so that the resulting product becomes insoluble in water.

Mixing the colloidal ammonium salt solution with the gel-treated poly (vinyl alcohol) produces a heterogeneous system of its own, retaining over 90% of water, miscible with acrylate or vinyl acetate dispersions. It can be further treated with additives. Example 2

Dilute 100 ml of a colloidal 10% aqueous solution of sodium polymethacrylic acid with 100 ml of water. By treatment with a mineral acid such as 10 ml of 36% HCl, the sodium salt of polymethacrylic acid is converted to the free acid. This operation is carried out at normal temperatures up to 20 ° C. The free polymethacrylic acid is washed with cold water to remove NaCl residues as an unsuitable electrolyte. Thereafter, the free polymeric acid is converted into a soluble ammonium salt by the ammonia solution. Ammonia is added in portions until everything is dissolved. A small excess of ammonia is not a problem.

The consumption is about 20 ml of a 25% aqueous ammonia solution. Conversion of the obtained reversible polymethacrylic acid ammonium salt colloid to irreversible colloid is accomplished by carefully adding a 10% solution of aluminum sulfate (or other aluminum salt) in water while stirring. This operation is very delicate and requires ongoing checks to avoid total coagulation of the ammonium salt. To this end, it is advantageous to use individually tested coagulation curves and to further control coagulation both in the mixture itself and by monitoring the loss of opalescence of the product. This is done by adding a drop of product to the very dilute ammonium chloride solution and monitoring the blue opalescence of the solution. Only a slight opalescence should occur in a few moments.

When the desired coagulation point has been reached, the heterogeneous system thus formed is left to rest. It consists of a colloidal ammonium salt solution in which the aluminum salt is dispersed. After a few hours, the dispersed gel swells again and forms a dispersion in the ammonium salt sol. This dispersion is finer when added to the ammonium salt solution, eg traces of stearylamine, during coagulation.

The product obtained in the form of a heterogeneous system can be further treated with various additives analogously to Example 1. The dispersion is added in an amount of 30 to 50% by weight to the dispersions and emulsions or temper colors. Example 3

100 ml of an aqueous suspension of the purified product of esterification of methacrylic acid with glycerol, prepared according to CS. No. 185008, which has been purified by decantation and left in H ⁺ form, is ammoniaized with an excess of aqueous ammonia until a pH of 8.5 is reached. To this colloidal solution was added 10% ammonium phosphate solution in an amount of 6 ml. This micro-heterogeneous system leaves a very fine residue after the water has evaporated. It is readily miscible with acrylate and vinyl acetate dispersions.

Example 4

100 g of powdered copolymers of (2-hydroxyethyl) acrylate and (2-aminoethyl) acrylate in a molar ratio of 70: 30 mol%, prepared according to U.S. Pat. No. 154466 is suspended in one liter of water and 100 ml of a 5% aqueous glutaraldehyde solution is added to this suspension and allowed to react at room temperature for 45 minutes with stirring in a high speed mixer. 500 ml of water are then added and thoroughly mixed to a fine suspension, which serves as an additive to the acrylate or vinyl acetate dispersions.

Example 5

The procedure of Example 4 was followed, but the copolymers of (2-hydroxyethyl) methacrylate and acrylamide were used in a molar ratio of 60: 40 mol%. An aqueous 40% formaldehyde solution in an amount of 5 to 8 ml can also be used for crosslinking.

Example 6

Following the procedure of Examples 4 and 5, however, poly (N - (2-hydroxypropyl) methacrylamide prepared according to US Patent No. 166553 was used as polymer).

Example 7

Following the procedure of Examples 1 to 6, a finely divided pigment such as cyanine blue is added to the resulting product in an amount of up to 50% of the dry weight of the polymer composition.

The dispersions according to the invention, in particular those prepared according to Examples 1 to 6, can be further treated or used as additives. For example, the addition of 1/10 to 1/5 of the paint in oil paints gives rise to a so-called emulsion oil paint that dries faster and harder than the original oil paint; the color is “shorter” and makes brushing easier.

Or to the thick copal lacquer or

SUBJECT

Claims (2)

SUBJECT Process for the preparation of micro-heterogeneous systems - emulsions, dispersions or suspensions - with increased water retardation, characterized in that from synthetic polymers or copolymers of alpha, beta-unsaturated carboxylic acids and their esters selected from the group consisting of esters with aliphatic polyhydroxy compounds of the alkylene glycol type wherein the alkylene has 2 to 6 carbon atoms, their polyesters with ether and derivatives, e.g. popřípadě, Ν-disubstituted with alkyl of up to 6 C carbon atoms, which alkyl may be further substituted with a hydroxyl or amino group at any position, aminoalkyl esters of alkyl of 1 to 6 C atoms, e.g. 2-aminoethyl methacrylate, wherein the amino group may further be N-monosubstituted or N, N-disubstituted by alkyl of up to six carbon atoms, prepare aqueous colloidal solutions, and these are ionically crosslinked by first-polymerized oil with a small amount (about 2 wt. invention. We obtain a dispersion with an external oil phase (VO), which is used as a so-called medium, allowing the application of pasty glazing paints. The dispersions according to the invention are used to treat the canvas before the actual painting (so-called specks). Use dispersions either alone or with the addition of usual substances such as float chalk, tinting dyes, etc. It is also possible to use the dispersion for retouching the painting or even as a final varnish. The dispersion can also be tinted by conventional dyes.