DD281802A5 - PROCESS FOR PREPARING HIGHLY RESISTANT CERAMIC PURPLE PAINTS - Google Patents

Abstract

The invention relates to a method for the production of ceramic highly resistant magenta colors, which are used for the decoration of ceramic products. With the method according to the invention, highly resistant ceramic magenta colors are produced while ensuring the opacity and brilliance characteristic of these colors. According to the invention, the highly resistant ceramic magenta dyes are prepared by adding a gold-free pigment and a suitable highly resistant flurizing agent to a mixture of gold purple mud and modified lead borosilicate glass. Gold-free pigments are pink-colored bodies, that is to say, chromium oxide or cassiterite and / or malayaite doped with chromium oxide and cobalt oxide. The ratio of the highly resistant ceramic purple color to gold-free pink pigment with the required Fluszmittelanteil in bright ceramic magenta 0: 1 or in the dark ceramic magenta 9: 1. The highly resistant ceramic magenta inks prepared according to the present invention can be applied to the ceramic article in conventional processing techniques such as printing, painting and spraying. {Highly Resistant Purple; reduced fine gold content; Use of pink color bodies; Combination with purple}

Description

depending on the use of the ceramic color magenta either dried and processed or subjected to an annealing process at 600 ⁰ C and then finely crushed, dried and then processed.

The pink color bodies used according to the invention are cassiterite doped with chromium oxide or with chromium oxide and cobalt oxide

and / or malayaite. The cassiterite-based color body is also referred to as pink lilac, and the malayoite-based color body as pink-red.

It was found that in very bright purple hues, the mixing ratio between the highly resistant ceramic Purple color and the gold-free pink pigment with the required flux content to 0: 1 is possible without that Change color level, clarity and color saturation of the color. For purple colors with high color saturation is a mixing ratio

highly resistant ceramic purple color: gold-free pink pigment with required flux only up to 9: 1 possible.

At medium color saturation values, the admissible mixing ratio is in between. This combination possibility is surprising, since pink colors, consisting of kaiterbody of the type Kassiterite and / or

or malayaite and a suitable highly resistant flux, a lead borosilicate, distinguish in clarity from the highly resistant ceramic magenta in that the black level is 10% -20% higher than in highly resistant ceramic magenta. The cause of this surprising effect in the combination of colloidal gold colored glass with one or both pink pigments is the dominance of coloration by the colloidal disperse phase portions. This shows the gold-free pink pigment or pink pigment mixture against the

See through the white ceramic or porcelain surface a covering effect, while the colloid disperse Goldglaseinfärbung cause the color and brilliance. It has been found that the color grades carmine red and magenta require predominantly pink pigments of the malayaite type,

while for the color shades purple violet and violet the pink pigment of the type Kassiterit or a Pinkpigmentgemisch the

Types of cassiterite and malayaite are required. The mixing ratio depends on the degree of blueness of the hue. It is also possible for the color grades Purple violet and violet pink pigments on the bass cassiterite and / or malayaite, which already contain cobalt oxide,

or by adding cobalt oxide to the flux component to color this ionogen blue.

As a suitable Flußmittelzusammensetzi'ng proved:

PbO .Teile lead oxide B ₂ O ₃ 57.5 boron oxide SiO ₂ 9.7 silica Na ₂ O + K ₂ O 25.7 alkali oxides CaO + MgO 1.9 alkaline earth oxides TiO ₃ 1.9 Titanium dioxide Al ₂ O ₃ 0.6 alumina ZrO ₂ 2.2 zirconia 0.5

The mixing ratio of the pink colorant to the suitable flux varies depending on the colorant type. The reason for this lies in the different specific weight of the two Pink color bodies, which lies at the cassiterite at 6.8 g / cm ³ and at malayaite at 3.8 g / cm ^3.

The highly resistant ceramic magenta inks produced according to the invention can be applied to the ceramic article in conventional processing techniques, such as screen printing, painting and spraying. After the decorative firing in the range 800 ° C-860 ° C, 900 ° C-1000 ⁰ C or 1050 ° C-125O ⁰ C, a bright color layer in the colors carmine red, purple, purple purple and purple is obtained. The burnt-on color corresponds to the usual characteristic values for highly resistant ceramic colors.

embodiments example 1

A highly resistant bright red ceramic purple color is prepared by mixing 20 parts of a pink red colorant-chromium oxide doped malayaite with a Cr ₂ O ₃ content of 1.3% - with 80 parts of a highly resistant flux of the following chemical composition

PbO 57.5 parts

B ₂ O ₃ 9.7 parts

SiO ₂ 25.7 parts

Na ₂ O + K ₂ O 1,9TeMe

CaO + MgO 1.9 parts

TiO ₂ 0.6 parts

AIO ₃ 2.2 parts

ZrO ₂ 0.4 parts

be prepared in the usual way.

After pasting with screen-printing oil, the ink is screen-printed on slide paper and the slide image is then transferred to a porcelain surface and baked at 820 ^° C. After firing, a bright color surface is obtained, which is arranged in the 24-part color circle as follows:

Color level carmine red

Clarity 90%

Whiteness 90%

The lead release under the test conditions of a 24-hour exposure to 4% acetic acid at room temperature is 0.55 mg lead per square decimeter of color area. The highly resistant crimson ceramic purple color according to the invention is gold-free and corresponds in its coloristic characteristics of a highly resistant ceramic purple color with a gold content of 0.79 gf per kilogram of color.

Example 2 A highly resistant medium intense red ceramic purple color is prepared by mixing 60 parts of a dark,

gold-containing high-resistant purple color with 32 parts of a highly resistant flux - with a chemical

Composition according to Example 1 - and 8 parts pink red pigment according to Example 1. After processing analogously to Example 1, this is pasted with screen printing oil and screen-printed directly on porcelain

printed. The print on the porcelain surface is baked on bai 82O ⁰ C. After firing, rrvrieine receives a well-glossy color surface with grading values in a 24-part color wheel

Color group carmine red

Clarity 80%

Whiteness 40% The lead release value is 0.19 mg lead per square decimeter color area.

A color corresponding to the color without the pink red pigment content according to the invention has a gold content of 3.67 gf per kilogram of color. After the preparation according to the invention, the gold content is 2.23 gf per kilogram of color.

Example 3 A violet highly resistant ceramic purple color is prepared by mixing 3 parts of a dark purple Pink-colored coral oxide-containing chromia-doped malayaite with 7 parts of a highly resistant flow of Composition according to Example 1 and 90 parts of a violet gold-containing ceramic purple color. The cobalt-containing

Chromium oxide-doped malayaite color bodies contain 0.7% chromium (III) oxide and 1.9% cobalt (II) oxide.

After pasting the paint with screen printing oil, printing on sliding picture paper and then transferring the Pressure drawing on a porcelain surface of the porcelain article at 84O ⁰ C is fired in the industrial furnace. The Lead deduction is 0.58 mg lead per square centimeter of color area. The shiny color surface can be in the 24teiligen Classify color wheel as follows: Color level: Violet

Clarity: 70%

Whiteness: 40%

A color corresponding to the color on the basis of the gold purple mud contains 7.01 gf of gold per kilogram of color. After the preparation according to the invention, the amount of gold is 6.31 gf per kilogram of color for a hue of the same color.

Claims (3)

claims: 1. A process for the preparation of highly resistant ceramic purple paints, characterized in that gold purple mud and a flux are mixed to a purple color, the mixture pink color body and a highly resistant flux are added, all components are mixed intensively and then processed by process known to processable color. 2. The method according to claim 1, characterized in that the Pinkfarbkörper chromium oxide or chromium oxide and kobaltoxiddotierter malayaite and / or cassiterite. 3. The method according to claim 1 and 2, characterized in that the mixing ratio of the ceramic Pupurfarbe on gold purple mud base to Pinkfarbkörper and flux is between 0: 1 in light shades and 9: 1 in dark shades. Field of application of the invention The invention relates to a process for the production of highly resistant ceramic purple with reduced gold content for the decoration of ceramic products. Characteristic of the known state of the art Decorative surfaces of purple on ceramic products are molten lead borosilicate glass layers incorporating colloidal disperse elemental gold which causes the coloration. The preparation of the color takes place in such a way that reacts in aqueous solution hydrochloric acid H [AuCI ₄ I with tin dichloride SnCl ₂ , wherein elemental gold precipitates. By maintaining the known reaction conditions and adding substrate materials, colloidal gold particles are formed in a particularly high degree of dispersion, referred to as Cassius gold purple or gold purple mud. The gold purple mud, together with a suitable lead borosilicate glass, forms the material basis for the production of purple ceramics. The production of the purple color is carried out in such a way that a certain proportion of the gold purple mud is mixed with an appropriate amount of a suitable finely ground lead borosilicate glass or a mixture of several lead borosilicate glasses. The mixture may be added to further control the hue formation to red or blue silver or cobalt compounds. This mixture can be processed directly as a paint or annealed at 600 ° C-700 ° C and then crushed by a milling process ready for processing. During the decorative firing melts the decorated color surface on the top of the ceramic article au. In this melting process, the highly dispersed, colloidal gold particles in the lead borosilicate melt agglomerate into colloidal-disperse particles whose size is optimal for maximum color tone formation. The chemical and physical properties of lead borosilicate melt thus contribute significantly to the color tone formation. As a result of this agglomeration at baking conditions in the temperature range 820 ° C-860 ° C, a colored glass, the color intensity is essentially dependent on the gold content. The gold content of the purple colors is in the range 0.1% -?%. The color palette of purple colors in the 24-part color wheel includes the color grades carmine red, purple, purple purple and violet. The clear range is between 100% and 70%, preferably between 90% and 70%. The color saturation of the purple ceramic decorations ranges from 100% to 50%. The required color saturation is controlled either by different color coat thickness or at constant color coat thickness directly over the gold content in the color. In both cases, the desired color saturation value depends on the gold bet. Like all ceramic colors, purple colors should also have a high stability against the action of acid. In general, the colors are referred to as being highly resistant, which upon exposure to ^v: Write erprozentiger acetic acid at room temperature over a period of 24 hours is less than 1 mg of lead per square decimeter color area. The highly resistant magenta inks used for ceramic decoration have a lead emission of less than 1 mg lead per square decimeter under the test conditions mentioned. Object of the invention The object of the invention is a process for the production of highly resistant ceramic magenta colors with reduced gold content of the Farhan while ensuring unimpaired opacity and brilliance. Explanation of the essence of the invention The object of the invention to reduce the gold content of highly resistant ceramic solid colors with unchanged opacity and brilliance in the color range from carmine to magenta, magenta to violet, is achieved according to the invention in that the highly resistant ceramic magenta color consisting of a mixture of gold purple mud and a matched lead borosilicate glass , a gold-free pigment and a suitable flux are added. As gold-free pigments Pinkfarbkörper be used. The pink color bodies are with a suitable; highly resistant flux, a lead borosilicate glass and the highly resistant ceramic purple color mixed and ground in alcohol and