SU822757A3 - Pigment with mother-of-pearl shine and its preparation method - Google Patents

Abstract

1533430 Lustrous pigments MERCK PATENT GmbH 18 May 1976 [22 May 1975] 20491/76 Heading C4A Lustrous pigments consisting essentially of mica flakes coated with a plurality of metal oxide layers, the metal oxide layers being alternatingly arranged and comprising at least the succession rutile/stannic oxide/rutile, a layer of rutile with a thickness of at most 25 nm. lying on the mica may be produced by a process wherein mica flakes coated with a thin titanium dioxide hydrate layer are at least once first provided with a stannic oxide hydrate layer by deposition thereof from a stannous salt solution in the presence of an oxidation agent, followed by deposition of a titanium dioxide hydrate layer from a titanium salt solution, whereafter the product obtained is washed and calcined.

Description

one

The invention relates to the production of pigments, in particular to pearlescent pigments, which can be used in paint and varnish products, for example, for storing plastics, as well as in cosmetics.

Limes is a mother-of-pearl pigment based on mica flakes coated with several layers of metal oxides, containing titanium oxide as an internal coating on mica, and a layer of one or more coloring metal oxides, such as tin, iron, chromium, and nickel r. This pigment is obtained by sedimentation on salted scales of coatings of oxides of the corresponding metals from hydrochloric acid solutions of their salts fl}.

Also known is a pearlescent pigment based on fresh flakes coated with successive layers of tin oxide and titanium dioxide in an amount of 10-60% of the weight of the outcome of the first flakes when the content of tin oxide in the coating is 0.5-5. weight.%. The specified pigment is gyu; gucha from the path to mica scales after onate.1 and-i1: .1X oxide layers

tin and titanium dioxide when heated from aqueous solutions of salts of these metals, namely from an acidic solution of titanyl phosphate and chloride solution of two- or tetravalent tin, followed by washing the resulting product and calcining it {2.,

A disadvantage of the known pigments and methods for their preparation is the lack of high light and weather resistance of pearlescent products, which is caused, in particular, by the state of titanium dioxide in the known pigments mainly in anatase form.

five

The purpose of the invention is to improve the light fastness of the pearlescent pigment based on mica scales.

The goal is achieved by

0 that the proposed pigment with pearlescent gloss based on mica flakes coated with successive layers of tin oxide and the outer layer of titanium dioxide contains directly

5, on the initial flakes, a layer of titanium dioxide in rutile form with a thickness of 0.1–25 nm, then a layer of tin oxide, 2–25 nm, and again rutile titanium dioxide, 20–200 nm with a content of

0 components, weight %, Titanium dioxide 7-10 tin oxide3-25 mica flakes Else and method of its production by precipitating the original mica flakes of successive layers of titanium dioxide, tin oxide and again titanium dioxide from aqueous solutions of salts. these metals when heated, at the precipitation of tin deposition, in order to improve the smoothness of the coating, in the presence of an oxidizing agent, with the introduction of water-soluble aluminum salts in an amount of 0.01-2 m 6 l A1 per mole of subsequent scrubbing by rinsing the resulting product and calcining it . The invention makes it possible to increase the light resistance of pearl gum pigments based on mica flakes by points with a yellow tint and a points with a red tint in comparison with the known pigment, due to the complete rutilization of titanium dioxide as part of our proposed pigment. Thus, pearlescent pigment is mica flakes with a layer of rutile titanium dioxide with a thickness of 0.1–25 nm, then a layer of tin oxide, 2–25 nm with a content of 3–25 wt.%, Above which is covering outer layer of rutile titanium dioxide with a thickness of 20-200 nm. This arrangement of the layers in the proposed pigment can be repeated several times to achieve the desired interference light. The method of obtaining the pearlescent pigment is that the mica flakes are sequentially deposited on titanium, tin, and titanium hydroxides in succession from solutions of the salts of these metals. The coated mica in this case is usually suspended in desalted water and heated to .40-95 ° C, the first layer of titanium dioxide is precipitated from a solution of titanyl sulfate or titanium chloride to the required thickness. Thereafter, the tin hydroxide is precipitated from solutions of sulfate or tin (II) or (IV) chlorides in the presence of an oxidizing agent, for example, air, hypochlorites, and preferably potassium chlorate in an equivalent amount to the tin salt solution. In addition, hydrochloric acid may be added to the precipitated solutions. The pH is in the order of 0.5-3.0 at the stage of precipitation of the first layer of titanium hydroxide and to a pH of 0.1-5 at the stage of precipitation from tin salts. The concentration of the tin salt (s) solutions is in the order of 0.1 to 3 mol / l. When precipitating in accordance with the invention, water-soluble aluminum salts, for example the chloride salt, its acetate, nitrate or sulfate / and alkaline ammonium aluminum alum are introduced into the titanium and tin salts. Enter the aluminum salts preferably in an amount of 0.01-2 mol per mole Sn salt (li). In the process of said precipitation of hydroxides, maintenance is preferably; with the pH of the reaction mixture at a constant level, which is provided by the addition of an alkali metal hydroxide or aluminum, or gaseous ammonia. The last third layer of titanium dioxide, color-forming, is applied similarly to the first of the titanium salts at 0.5 to 5.0 at 50100 ° C. In this case, the interference light of the coating in this case depends on the thickness of the nanoscale layer, which is given below. Interference Thickness of the external lightness TiO2, nm Silver Yellow Yellow Purple Green. The deposition of successive layers according to the proposed method is preferably carried out without separating the resulting intermediate products. Covered mica flakes are isolated from the reaction mixture, mixed with water and dried. After that, they are calcined from 10 minutes to 4 hours at 600-1100 ° C. After this treatment, rutile-containing pigments are obtained, the X-ray diffraction patterns of which do not contain lines characteristic of anatase. The basis of mica scales is predominantly muscovite. The diameter of the flakes used is 5200 microns, the thickness is 0.1-5 microns. EXAMPLE 1: 120 g of muscovite flakes with a diameter of 10-50 microns are suspended in 2 liters of completely desalinated water. The suspension obtained is diluted with dilute hydrochloric acid and then heated to 75 ° C. While stirring, 60 ml of a solution of 150 g of Tie 14 solution are slowly added to it and 50 HCI per liter (solution 1) simultaneously with a 15% aqueous solution of sodium hydroxide, at a constant value of 2, 2 are then added to the suspension. 52 CSA and adjusted its pH to 1.4. After that, while stirring, 600 ml of tin chloride solution with a concentration (19.1 g of 5pCl, x per liter of 5% hydrochloric acid (solution II) are slowly added, and at the same time a 15% aqueous solution of sodium hydroxide is added while maintaining the pH constant, equal to 1.4. After about half an hour, the addition of these solutions is completed and 540 ml of solution 1 is added, maintaining a constant value, 2. Upon completion of this addition, the pH value is again adjusted to 1.4 and then slowly added of 1nn higher solution of olov chloride (solution of II) together with the solution m of sodium hydroxide. After this, 600 ml of solution T are again added to the reaction suspension at a pH value of 2.2 and 300 ml of solution II at a pH value of 1.4, and then 800 ml of solution 1 are again added at a pH value of 2.2. As a result, a pigment with a violet interference color is obtained, after which the pigment suspension is divided into two parts and an additional amount (90 ml) of solution I is added to one part, and a blue interference color pigment is obtained. Pigment is filtered from both parts of the suspensions, washed and dried. After that, each part of the obtained pigments section. They are put in two parts and calcined each part for half an hour at 700 ° С or 900 ° С, respectively. Thus, violet pigment, 1V / 700 calcined at 700s, violet pigment 1V / 900 calcined at 900s, blue pigment IB / 700, calcined at 700 ° C, blue pigment IB / 900, calcined at 900 ° is obtained. Measure 2 to obtain similar color pigments according to a known method. Example 2. A 1 liter glass stack, equipped with a stirrer and a heater, is filled with 850 ml of water at room temperature. 40 17 muscovite flakes with a diameter of 10-50 microns are added to the water, and the suspension is thoroughly mixed. 1.5 g of SnS04 (technically pure) is added to this mixture. The resulting mixture of mica, salts of tin and water is heated to, and then 51 g of 78% sulfuric acid is added to it. Maintaining the temperature at 80 ° C., Next, add 220 g of a solution of titanyl sulfate containing about 17% by weight of TiOi. The suspension is held at 80 ° C for 12 hours, after which its temperature is raised to its boiling point slowly over 2 hours. Then the mixture is kept for 1 h at reflux temperature. Then the flask with the contents is sharply cooled to. The solid is filtered off from the liquid phase of the suspension, the remaining acid is washed with water and dried. The resulting product, having a purple interference color, is divided into two parts and calcined, respectively, at 700 ° C or. 900 ° C In addition, a second sample of pigment is prepared, as above, but using only 30 g of raw mica flakes. In this case, a pigment of blue interference color is obtained, which is calcined at 700 ° C and 900 ° C, respectively. So get purple. pigment nV / 700, calcined at 700 ° C, purple pigment IIV / 900, calcined at, blue pigment PV / 700, calcined at 700 ° C, blue pigment PV / 900, calcined at 900 ° C. Next, in the resulting pigments, the crystal structure of titanium oxide is examined by X-ray diffraction. To do this, build a Debye-Scherer diagram for the pigment. The processing of the Debye-Scherer diagram gives the following results: Crystal structure of the TiO tour pigment, lV / 700 Anatase not detected lV / 900 lB / 700 IB / 900 nV / 700 IIV / 900 PV / 70 Approximately 20% anatase PV / 900 Approximately 5% anatase Research The light stability of these pigments is carried out when they are irradiated in a thin layer, followed by a visual assessment of the change in color. For this purpose, samples of paints based on appropriate pigments and aka containing 0.325 kg of high nitrocellulose, 0.325 kg of acrylic resin, 2.100 kg of N-butyl acetate as 85% solution in n-butanol are prepared.

1.825 kg of ethyl acetate, 0.825 kg of toluene and 0.175 kg of butanol.

These components in an appropriate proportion mix well and pot 5.330 kg of lacquer.

4.0 g of a sample of the corresponding pigment is added to 100 g of the obtained lacquer and the mixture is thoroughly mixed for 15 minutes. After that, it is left; stand for 2 hours to remove air bubbles and then apply a layer of 500 µm to the glass plate. After drying at room temperature, the resulting film is moistened with water and separated from the glassy plate.

The films obtained are irradiated with a conventional instrument. Upon irradiation, the smooth side of the corresponding film (the side which, when manufactured, was attached to the glass plate) is turned towards the light source. When illuminated, the film is covered with a frame that has an opening about 20 mm wide, so that only a part of the film is exposed to radiation, while the other part of the film remains protected from the radiation by the frame and thus retains its original color. Samples calcined at 700 ° C illuminate 127 h. Calcined samples are illuminated for approximately 824 h.

The change in the color tone of the illuminated sample is evaluated visually by a point system, with a greater degree of color change being evaluated by a large number of points. The total color change is expressed by the sum of points.

This assessment shows the color change of the proposed pigments and known pigments (Table 1).

Table 1

Thus, the results of the analysis show that the pearlescent pigments according to the invention contain titanium dioxide constantly in the form of rutile and have an increased light resistance, which follows from a slight change in their color in comparison with the known pigments.

Example 3 describes the production of pearlescent pigment according to the invention with the introduction of water-soluble aluminum salts in the process.

Example 3. 60 g of flakes of potassium mica with a diameter of 10-40 microns are suspended in completely demineralized water, adjusted to pH 2 with a hydrochloric acid solution of titanium containing 10% TiC, 5% HC and 10 g AlCl3 H6 O per 1 liter (solution 1). The suspension is heated to 75 ° C and 40 ml of solution 1 is slowly poured into it while adding sodium hydroxide solution while maintaining the pH of the suspension at a value of 2.0. After 15 minutes, 60 ml of solution 2 are added to the suspension, containing 200 g, 50 g of HCl and 50 g of AlClj-eH p per liter, while simultaneously adding 60 ml of a COOS solution at the same rate with a similar rate of 40 g / l , and a 15% solution of caustic soda, while maintaining a constant pH of the reaction mixture equal to 2.

After complete addition of the solution of | tin, the suspension is suspended for about half a minute until the salts are completely hydrolyzed.

Thereafter, oxide layers of titanium dioxide TiOj are alternately applied to the product obtained. and tin oxide Sn02 by introducing into the reaction, the suspension of the corresponding above-mentioned solutions 1, 2 and 3 according to the following scheme (Table 2).

table 2

1 yellow

1V / 700 18/700 4 red

27 n, V / 700 6 yellow PV / 700 b red 1V / 900

2 yellow 13/900

24 2 red nv / 900

4 yellow PV / 900

5 red

320

Tio "

60

60

SnO,

320

Tio,

60

60

SnO,

320

Tio,

60

SnO,

60

320

Tio,

SnO.

BO The pigment obtained is then washed, dried and calcined for 40 minutes. The pigment has an intense green interference color and good shine. A radiographic study indicates that titanium dioxide in its composition is entirely in the form of rutile. Paint coatings based on this pigment have improved smoothness and uniformity. 1. Pigment with pearlescent gloss based on mica flakes with a coating of successive layers of tin oxide and the outer layer of titanium dioxide, characterized by the fact that in order to increase its light fastness, it additionally contains on the mica flakes a layer of Titanium dioxide is the following ratio of components, wt.%: Titanium dioxide - - Tin oxide Else Mica flakes 2. The pigment according to claim 1, characterized in that it contains titanium dioxide in rutile form with a ratio of two layers KazISS GOVERNMENTAL titanium mica flakes, tin oxide and titanium dioxide external SOFT on the thickness (nm) -0,1-25: 2-25: 20-200. 3. A method for producing a pearly luster pigment, which includes precipitating on mica flakes successive layers of tin and titanium hydroxides from aqueous solutions of salts of these metals by heating, washing the resulting product and calcining it, which is previously applied to the initial mica flakes An additional layer of titanium hydroxide, and the deposition of tin is carried out in the presence of an oxidizing agent. 4. Method pop. 3, characterized in that, in order to improve the smoothness of the coating, the precipitation is carried out in the presence of water-soluble aluminum salts in the amount of 10.01 to 2 mol A1 on. mole Sn. . Sources of information taken into account in the examination 1. For the Germany, No. 1959998, cl. 22 f 1/00, published 1971. 2. Forward number 2214545, class 22 f 1/00, published, 1972 ..

Claims (4)

• Claim 1. A mother-of-pearl pigment based on mica flakes coated with successive layers of tin oxide and an outer layer of titanium dioxide, with the exception that in order to increase its light fastness, it additionally contains directly on mica flakes a layer of titanium dioxide in the following ratio of components components, wt.%: Titanium dioxide 7-70 Tin oxide 3-25 Mica flakes Rest 2. The pigment according to claim 1, with the fact that it contains _ titanium dioxide in rutile form with a ratio of the layers of titanium dioxide on mica flakes, tin oxide and the outer layer of titanium dioxide <5 thickness (nm) 0.1-25: 2-25: 20-200. _ 3. A method of obtaining a pigment with 5 with pearlescent gloss, including the deposition of successive layers of tin and titanium hydroxides on mica flakes from aqueous solutions of the salts of these metals when heated, washing and calcining the resulting product, characterized in that an additional layer of hydroxide is preliminarily applied to the initial mica flakes titanium, 15 and the deposition of tin is carried out in the presence of an oxidizing agent. 4. The method of pop.Z, characterized in that, in order to improve the smoothness of the coating, the deposition is carried out in the presence of water-soluble aluminum salts in an amount of 0.01-2 mol of A1 per. mole of Sn ¹⁺ . . 25 Sources of information taken into account in the examination 1. The application of Germany No. 1959998, class. 22 f 1/00, published. 1971. 2. Application No. 2214545, class 22 f 1/00, published, 1972 ·. Editor A. Naurskov Compiled by L. Romansev Tehred N. Kovaleva Corrector N. Shvydkaya Order .1909 / 85 Circulation 684 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 113Q35, Moscow, Zh-35, Raushskaya nab., 4/5 Branch of the PPP Patent '*, Uzhgorod, Project 4,