JPS59138268A - Manufacture of protected pigment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing protected pigments which are particularly suitable for firing onto ceramics and for use in plastics.

Many pigments, especially those used in the ceramic and plastic industries, have limited color and chemical stability. Such pigments may become unstable at high temperatures or in the presence of acids, resulting in discoloration and/or release of toxic metals from the pigment.

Solid solutions of cadmium di-sulfoselenide are extremely unstable, which is disadvantageous since the solution provides an excellent color range from yellow through red to violet. It is.

These pigments are sensitive to temperature and atmosphere and will react with lead-containing fluxes and other non-cadmium pigments to produce black stains. Despite the limitations of these pigments, they are the only known compounds that produce bright red colors for ceramic applications. In the case of plastics, cadmium sulfoselenide pigments are often used because they are stable enough to withstand the processing temperatures required by thermoplastics such as polystyrene and do not fade. There is. However, the use of these pigments in plastics may be limited as cadmium release may occur.

11 The most notable measures aimed at improving the stability of watery pigments, especially cadmium sulfoselenite pigments, are:
The protection is through the inclusion of this pigment within transparent zirconium silicate crystals. Pigments thus protected are sometimes encapsulated.
It is called d). In a known method, the pigment components, powdered zirconium oxide and powdered silicon dioxide are mixed with water to form a dough (+fugh) and the resulting mixture is heated to an elevated temperature and subsequently ground to remove unwanted reaction products.

Pigments produced by this method have sufficient saturation when baked onto ceramic products.
) suffers from the disadvantage that it is impossible to obtain a color with . This is because the cadmium sulfoselenide encapsulated within the zirconium silicate crystals is generally at a low level, approximately 1 to 2 percent of the total.
It is believed that impurities such as silicon dioxide, zirconium dioxide, unpigmented zirconium silicate, and poorly pigmented zirconium silicate reduce the chroma -Ji. These impurities are not removed by subsequent washing. The result is a pastel pigment rather than a highly saturated hue. The radiation reflectivity of known protected pigments is shown in graphical form in FIG. 1 and will be explained below. Written by W. Volka (W, Volk Or) [
"Include pigments and their use in various glaze systems"
sion pigments and tl+eir
use iηVarious glaze system
ms) "Glazes and glazing techniques"
Glazing Techniques) 7. See the publication of the Ceramic Association of Sweden, M9 1981.

The present invention seeks to eliminate these drawbacks of conventional pigments or to reduce Q<'6.

The present invention provides a method for producing protected pigments by the inclusion of a pigment in transparent zirconium silicate crystals in an aqueous or non-aqueous solution of their salts. This provides a means by which precipitation can be performed simultaneously or sequentially.

The minor invention also provides a method for preparing protected pigments by incorporating the pigments within transparent zirconium silicate crystals, the components of the protected pigments being simultaneously or sequentially removed from aqueous or non-aqueous solutions of their salts. There is also provided a method comprising: precipitation to form a precipitate; mixing this precipitate with a fluoride; heating the mixture to i;% temperature; and means for washing the protected pigment thus obtained. It is.

The aforementioned components are preferably (a) a pigment or its precursor, (b) a zirconium hydroxide or zirconia hydrate, and ((1) a silicic acid or silica permanent hydrate).

The protected pigments prepared according to the method described above contain about 8-10% cadmium sulfoselenide pigments contained within zirconium silicate crystals and have poor to no pigmentation. Contains no acid zirconium.

The X-ray diffraction spectrum shows a peak at a d spacing of 2.96 people, which is attributed to a small amount of cubic zirconium dioxide. This X-ray diffraction peak at 2968 was not detected in the commercially available protected face A,1. Commercially available products include 283 and 316 d-space sinks, which are barely detectable in illegally manufactured protected face materials, and monoclinic dioxide. Zirconium 1
1) Do.

According to previous research, cubic zirconium dioxide has a
It is clearly present in the protected pigment with a proportion of ~6% by weight. It is believed that this may be due to the presence of finely divided pigments, especially cadmium.

It is also believed that the presence of the Ifj PI may be a contributing factor to the richness of tone exhibited by the protected pigment.

In the case of firing on ceramic products, this produces bright colors with sufficient saturation, which colors have been tested according to the methodology of the 1972 edition of British Standard 4860, Part 1, 'Limits for metal emissions from glazed ceramic products'. No detectable cadmium release occurs. This bright red, orange and O/yellow cadmium sulfoselenide pigment is
It can be applied to tableware when transferring decoration onto a glaze which is baked at 800 to 850°C. This pigment is completely compatible with the lead-containing fluxes commonly used for glaze decoration.

These pigments can also be used in the glaze decoration of tableware (baking temperature 1050°C) and as glaze stains for tiles and sanitary ware (baking temperature 120°C).
It has sufficient heat resistance to allow temperatures up to 0°C. In glaze stain applications, the vibrancy of the color depends on the refractive index of the glaze. The most saturated color is ir
T! J Chisel Stomach in 41 large lead-containing glazes. These sleeve lengths are 1. The refractive index of zircon in the '□J area is +'a'', q, which minimizes the opaque effect of the zircon.Lead-free glazes with a refractive index or lower, such as those used in sanitary IIfl'j ware. However, the protected red pigments produced by the present invention produce much more saturated reds in lead-free glazes than previously available. give.

The process for producing protected pigments according to the invention is suitable for use with pigments of limited stability, in particular cadmium sulfoselenides, cadmium mercuric sulfide and similar sulfides containing zinc and/or tellurium, gold, tin and similar sulfides. Suitable for gold zirconia pink, chrome yellow, cobalt zinc blue and copper color.

Tort may be used as a "post-processing" method for existing (non-persistent) pigments and is therefore desirable for use by pigment users who do not wish to make any modifications to their pigment formulations. Alternatively, illegality can be applied to the in-situ production of pigments that are unprotected.

The constituents of the protected pigments according to the invention are pigments or their precursors, zirconium or luconia hydroxide hydrates and silicic acid or silica permanent hydrates. Any soluble zirconium salt can be used to obtain the zirconium component, such as zirconium chloride, zirconium nitrate, zirconium sulfate, zirconium acetate and similar salts. soluble silicates,
For example, sodium silicate, potassium silicate, lithium silicate or ethyl silicate may be used to obtain the silicate component. fluorides, preferably metal fluorides;
Examples are sodium fluoride, lithium fluoride, fluoride 1j
), potassium fluoride, calcium fluoride, and thorium aluminum fluoride can be similarly added in an amount of 0.1 to 15% by weight, preferably 1 to 3%. The mixture is baked preferably between 800 and 1300<0>C, preferably above 1000<0>C, for at least 1 minute, preferably 10 to 15 minutes. The calcined product is then crushed, powdered and treated with acid, alkali and water to remove unnecessary reaction products and unprotected pigments, and the product is finally dried.

Embodiments of the present invention will now be described with reference to FIG. 2 of the accompanying drawings, and FIG. 1 will be referred to for comparison.
The properties of the known protected pigments for ceramics are described below.

These figures show graphs of the reflectance of electromagnetic radiation (y-axis) versus the wavelength of that radiation (x-axis) of a glaze sample, and Figure 1 shows a graph of the reflectance of a glaze sample for a known protected pigment for ceramics. FIG. 2 shows a diagram of a pigment prepared according to the invention as follows.

Example 1 29 g of cadmium sulfate was brought to 78 M in 300 cJ of water and this solution was then mixed with 140 g of a solution containing about 35% zirconium acetate.

Powdered selenium 3.67 was added to sodium sulfide solution (28!i'
was dissolved in 1000 d of water (1W) and then made alkaline by addition of ammonium hydroxide solution.

The two solutions were mixed together, the resulting precipitate was washed, filtered and dried, and the dry powder was diluted with 35 cm of thorium silicate solution to 200 cm. Mix and neutralize with acid to form a gel. Wash this gel with water, filter it, and dry it at 1300C to remove fine powder.

This powder was dry mixed with 3x I1j% of lithium fluoride and calcined in a closed chamber at 1050°C for 30 minutes. The resulting red pigment composition was ground in a Bonyl mill and then washed with a mixture of concentrated sulfuric and nitric acids. This was subsequently washed with water, then 5M sodium hydroxide and finally water. The protected red pigment thus produced contained 59% by weight of cadmium. This protected red pigment was completely stable to acids, alkalis and temperatures of 1200°C. This produced a bright red color in the glaze decoration of tableware. This glaze upper limb holder in the form of a sill/screen type water/slide transfer 1 c
Applied to pawn china plates as a color block.

Transfer this onto the glaze with 1 part of red face 'A] and 2 parts of lead-containing flux.
It was done in the club. A bright red block was obtained after coating on a plate and curing U1 dimension at 800°C. The cadmium emission of this decoration is B.

S. 4860, Part 1, 1972 procedures. The measurement of color development in this application as a glaze top decoration and glaze layer = one coloring agent is as shown below.

Note: Color measurement conditions: Observer 2° Light source C Excluding specular reflection The purity of this red pigment is high, as shown in Figure 2.
The reflectance spectra for the lead based tile glaze containing the two decorations are shown in FIG. 1, and the lack of purity and definition of the red color is evident.

Example 2 108 g of zirconium chloride and 28 P of cadmium sulfate were dissolved in 500 d of water. This solution is then sulfurized)
28.59 ml of IJum was dissolved in 1 d of water and added to the solution containing ammonium hydroxide.

The resulting precipitate was decanted, filtered, and dried at 130°C, and then 60 d of sodium silicate solution (specific gravity 142) was diluted with water to approx.
It was added to the solution diluted to 50d. This solution was gelated as described in Example 1. The obtained fine powder was dry mixed with 1 part by weight of lithium fluoride and calcined in a crucible at 1050° C. for 15 minutes. The resulting yellow pigment composition was whole milled and r(
Washed with water and alkali.

-H: When the color coordinates of the "I'i bright protected yellow pigment were measured under the same conditions as in Example], the following color coordinates were shown for ceramics.

Example 3 A red/purple gold colloid was prepared on zirconia hydrate from zirconyl chloride and chlorinated acid in a conventional manner. The precipitate was filtered and wet mixed with neutralized silicic acid to precipitate the silicic acid. The mixture was filtered, washed and dried to a powder, which was then combined with LiF
3% by weight and calcined in a closed crucible at 1000° C. for 10 minutes.

The reaction product was treated by the procedure described in Example 1, and 1
A protected purple pigment was obtained which is stable at humidity above 000°C.

Example 4 Red and yellow pigments tuned according to the method described in Examples 1 and 2 were pole milled for 24 hours to obtain a finely ground, protected pigment suitable for plastics. After ball milling, the pigment had a specific surface area of 10 i/liter due to nitrogen absorption. These two types of protected face A;1 were added to the polystyrene in Section 3.3.

When this polystyrene was melted and embossed into a plate, the following color coordinates were obtained, measured under the conditions used in Example 1.

Zircon-protected instant J:il produced according to the present invention
has the following advantages compared to commonly available pigments of this type:

(1) The reactive components are finer and more reactive, resulting in a smaller proportion of the pigment within the protective crystals,
and correspondingly higher proportions and correspondingly higher pigment deposition densities within the silicon crystals are obtained.

Therefore, protected pigments have much higher chroma for a given particle size.

Instead, for a given saturation, there is grain or even noticeably finer detail.

+21 This highly chromatic protected pigment maintains exceptional stability towards heat and acids.

(3) Protected pigments produced illegally are more reproducible in color and particle size due to the improved control of zircon inclusion facilitated by the present invention.

(4) Better uniformity in unreacted or nearly unreacted or pigment-free material. The protected pigment consists of a single, uniformly colored particle, which results in a more uniform color in the ceramic article.

The inclusion pigments produced according to the invention are suitable for ceramic applications, and in fact this is likely to be their primary use.
It should be done. However, such pigments are also suitable for other applications, for example for use in plastics.

Although the temperature stability of this pigment is certainly within the 111,111 degree range for plastics manufacturing, the main advantage of using the pigment according to the invention in plastics is that they can be incinerated or used in food products. or that there is no release of toxic substances from the pigment when exposed to other substances that attack the protected pigment.

[Brief explanation of drawings]

Both Figures 1 and 2 are graphs showing the relationship between wavelength of electromagnetic radiation and reflectance. Depth (nm) Diagram 2 Beam length (nm) Penkhull Queens Road, Staffordshire, Stoke-on-Trend, England (no address) The British Ceramic Research Association Limited

Claims (1)

[Scope of Claims] (1) A method for producing protected pigments by incorporating the pigments within transparent zirconium silicate crystals, wherein the components of the protected pigments are dissolved in aqueous or non-aqueous solutions of their salts. A method characterized by simultaneously or sequentially precipitating from (2) Electron A・into transparent zirconium silicate crystal
A method for preparing protected pigments by the inclusion of I, comprising simultaneously or sequentially precipitating the constituents of the protected pigments from an aqueous or non-aqueous solution of their salts to form a precipitate, and converting the precipitate into a fluoride. , heating the mixture to a high temperature and washing the protected pigment thus removed. (3) A patent claim characterized in that the constituent components are (a) a pigment or its precursor, a mold material (1)) zirconium hydroxide or zirconia hydrate, and (G) silicic acid or silicate hydrate The range of the second term is the person of the first pod. (4) Pigments or their precursors, zinc, cadmium
Selected from the group consisting of minilum or mercury sulfide, selenide or telluride or mixed crystals thereof, gold-tin pink, gold-tin pink, chrome yellow, cobalt-zinc blue and copper-colored or their precursors. 4. The method according to claim 3, wherein the method causes swelling. (5) Zirconium hydroxide or zirconium hydrate, or one of IrY containing zirconium nitrate, zirconyl chloride, zirconium sulfate, and zirconium acetate
A method according to claim 3 or 4, characterized in that the zirconium component is obtained from one or more soluble salts. (6) Contains a silicon component obtained from silicic acid, permanent silica, or soluble silicic acid selected from the group including sodium silicate, potassium silicate, lithium silicate, and ethyl silicate. A method according to any one of claims 3 to 5, characterized in that: (7) The method according to claim 2, wherein the fluoride is a metal fluoride selected from the group including fluorides or mixed fluorides of aluminum, lithium, lead, potassium, calcium, and sodium. . (8) A method according to claim 5, characterized in that fluoride is added in an amount between 0.1 and 15% by weight. (9) Process according to any one of claims 2 to 8, characterized in that the mixture is heated to a temperature between 800 and 1300C. 10. A method according to any one of claims 2 to 9, characterized in that the mixture is heated to the humidity for a period of more than 15 minutes. (11) Any zirconium dioxide present in the protected pigment is wholly or substantially in the form of cubic zirconium dioxide.
The method described in section. Claim 2, characterized in that any zirconium dioxide present in the protected pigment is wholly or substantially in the form of cubic zirconium dioxide.
9. The method according to any one of 9.