MXPA98010796A - Labels and printing inks containing hollinmodific - Google Patents

Abstract

The invention relates to printing inks and lacquers, which contain soot as a black pigment. By the use of soot containing silicon the stability in dispersing and storage of printing inks and lacquers can be improved. The fluidity of the lacquers is improved by means of the silicon endowment of the soot used. Thus, lacquers with a reduced solven content are possible

Description

LABELS AND PRINTING INKS CONTAINING MODIFIED HOLLIN DESCRIPTION OF THE INVENTION The invention relates to lacquers and printing inks which, as a pigment, contain soot. In printing lacquers and inks, soot is predominantly used as a black pigment because of its outstanding properties. In addition to pure black colors, soot is also used to give tones along with other pigments, especially for the preparation of gray shades by mixing the soot with white pigments such as titanium dioxide and other white pigments. There is a wide selection of soot for pigments with different properties. Different procedures are used for the preparation of soot for pigment. The most frequent is the preparation by means of oxidative pyrolysis of soot raw materials containing carbon. For this the raw materials for soot are incompletely calcined at high temperatures in the presence of oxygen. To this kind of soot preparation process belongs for example the oven soot method, the gas soot method, the carbon black process. As carbon-containing soot raw materials, predominantly polynuclear aromatic soot oils are used. The product stream of oxidative pyrolysis consists of a waste gas REF. 29106 which contains hydrogen and carbon monoxide and fine particulate soot suspended in that gas, which is separated from the waste gas in a filtration facility. The process of preparation by means of oxidative pyrolysis belong to the oven soot method, the carbon black process, the gas soot method. The furnace soot procedure is performed incomplete combustion in a reactor coated with a material very resistant to fire. Here a flame is produced in the pre-combustion chamber by burning a fuel / air mixture, in which the raw material of the soot is sprayed or injected. The soot that forms is expelled from the reactor by means of water spray and is separated from the gas stream. The soot oven procedure allows the preparation of soot with a wide range of soot technical properties. Flame and gas soot procedures represent important alternatives to the kiln soot process. They produce soot, the properties of which almost coincide with the technical properties of the soot obtainable by means of the soot-oven process, but also allow the preparation of soot which can not be prepared by means of the soot-oven process. The oven soot apparatus consists of a cast iron capsule, which receives the fluid or possibly melted raw material, and a masonry extractor cover.

The division of the air between the capsule and the extractor cover as well as the sub-pressure in the system serve to regulate the air supply and with this its influence on the properties of soot. As a consequence of the thermal radiation of the extraction hood, it evaporates the raw material and it is partially calcined, mainly it is transformed into soot. For the separation of the soot, the process gases are passed after cooling in a filter. In the gas soot process, first the soot raw material is evaporated in a stream of carrier gas containing hydrogen and then burned in multiple small flares below a cooled cylinder. A part of the soot formed adhere to the cylinder, a part is carried by the process gases and separated in a filter. The important properties for evaluating soot for pigments are color depth t (in accordance with DIN 55979), color concentration (according to DIN EN ISO 787/16 and DIN EN ISO 787/24), oil consumption (according to DIN EN ISO 787/5), and the volatile constituent parts (according to DIN 53552), the structure measured as DBP adsorption (according to DIN 53601, ISO 4656 or ASTM D2414), the average primary particle size (by means of the evaluation of the takes by means of electron microscope) and the pH value (in accordance with DIN EN ISO 787/9 or ASTM D1512). Table 1 shows the properties of the soot for pigments obtainable by means of the aforementioned preparation methods. Table 1 : The most important properties for the selection of soot for pigments are their depth of color and structure. The depth of the color directly from the particle size. The less the particles are, the deeper the color of the soot in the pigment. Thus the particle size influences other properties such as oil absorption and viscosity of the final lacquer or printing ink. The structure of soot also influences the viscosity of the finished product and is important for the manufacture and preparation of lacquers and inks. The high structure causes high viscosity with the same amount of pigment and vice versa. The technical properties of a lacquer or an ink are the stability of the soot dispersion in the binder system (storage stability), the flotation capacity in pigment mixtures and the rheological properties of the lacquer or ink (viscosity and thixotropy). The stability of the soot dispersion in a binder can be improved for example by the addition of highly disperse silicic acid. However, the silicic acid can increase the viscosity of the product in an undesirable way. The high viscosity can be reversed by the repeated addition of solvents. The lacquers may have a so-called flotation characteristic, when they contain a mixture of pigments. The characteristic of flotation is understood as the observation that, for example, in gray lacquers in the lacquer drying process, the white pigments and soot are separated and cause color variation. This behavior can easily be verified by means of the so-called "Rub test". Here the lacquer is applied on a test surface. After a short drying, one half of the test surface is scrubbed with the finger. If a separation of both pigments occurs by means of flotation, then that separation will be reversed by means of the mechanical manipulation when rubbing, and a clear difference of color between both halves can be recognized. This property can be conducted during the practical use of the lacquer in different shades of color and therefore should be kept as small as possible. During the application of the pigment, high concentrations of soot are obtained. This leads to economic advantages due to the higher yields as well as ecological advantages due to the reduced need for solvents and the possibility of manufacturing low lacquers in solvents with a high solids content. The task of the present invention is the provision of printing lacquers and inks which, as regards their storage stability, flotation behavior and solvent requirement, are better than conventional lacquer formulations. Printing lacquers and inks in the context of the invention are also understood as inks for ink jet and dye printers. This task is solved by means of a lacquer which contains as binder system of the lacquer and soot as pigment. The lacquer is characterized in that the soot contains 0.1 to 30% by weight of silicon calculated as silicon dioxide, in relation to its total weight. Soot containing silicon are known, for example, from WO 96/37547. They are described in that writing for the use of rubber mixtures. Soot containing silicon can be prepared, for example, in such a way that silicon-containing compounds are added to the raw material of the soot. Alternatively, there is also the possibility of adding the silicon-containing compounds just before or directly in the soot-forming zone of the educt stream of the soot preparation process in question. Suitable silicon-containing compounds are organosilicon compounds such as oganosilane, organochlorosilane, siloxane or silazate. In particular, silicon tetrachloride, siloxane and silazane are suitable. Preferably ethyl or methyl ester of silica is used, siloxane and silazane for the preparation of soot containing silicon. These substances are preferably mixed in the raw material for soot. In the use of nitrogen-containing silicon compounds such as silazanes, for example, in the case of soot, in addition to silicon atoms joined by oxidation, nitrogen atoms are chemically bonded, for example in the form of aminofunctional groups. These soots depending on the nitrogen content of the starting compounds and their concentration in the soot raw material can contain 0.01 to 2% by weight of nitrogen in addition to the silicon. Surprisingly, the soot containing silicon in lacquer binding systems and in printing ink vehicles shows very positive properties. Thus, for example, the dispersion stability of the lacquer is increased, without substantially impairing the viscosity of the lacquer. This is unexpected, since the usual procedure to increase the storage stability by the addition of highly dispersed silicon acid, that is by the separate addition of a silicon compound to the lacquer binder system, also results in a thickening of the lacquer. The use of silicon-containing soot on the contrary improves the storage stability without thereby increasing the viscosity in the same way as when the storage stability of silicon-free soot is improved by the addition of highly dispersed silicic acid. The viscosity of the lacquers or printing inks is usually improved by the use of highly structured soots with BOD adsorption values greater than 100 ml / 100 g. By the use of soot containing silicon the viscosity can be clearly reduced. This allows organic lacquer binders to adjust a desired lacquer viscosity with reduced amounts of solvents. In the manufacture of gray lacquers with white pigments such as for example titanium dioxide and / or zinc oxide using the silicon-containing soot, a clearly reduced flotation behavior of the lacquer is shown as an additional positive property of these soot. In addition to the combination with white pigments, the advantageous properties of silicon-containing soot can also be used in combination with colored pigments such as, for example, cadmium, cobalt and iron compounds with different chemical construction. In a particularly advantageous manner, the soot containing silicon can also be used in combination with flake-shaped pigments such as pearlescent pigments and aluminum flakes. These pigments can lose all their effect only when they have the possibility of being aligned in parallel in the lacquer layer. Lacquers with low viscosity and low thixotropy would be desirable here. The reduction of the viscosity of a lacquer by means of silicon-containing soothes thus relieves the orientation of the pigments in the form of plates, for example leading to a better pearling effect. The following examples illustrate the invention in more detail. The determination of the technical properties of the lacquer was carried out according to the following methods and standards: Number of black My (depth of color): DIN 55 979 Density (optical density): According to the catalog of pigments no. 24 from Degussa AG; page 13 Opacity / brightness: Measurement with an opacity / brightness meter of the firm Byk in accordance with DIN 67530. Vi seosity Measurement with a rotation viscometer according to ISO 3219 / DIN 53019. thixotropy index: according to the catalog of pigments no. 54 of Degussa Ag, page 3 Flotation behavior: DIN 55 945. The number of black and (depth of color) is commonly used to characterize lacquers and deep black printing inks, gray lacquers on the contrary is evaluated with the help of the optical density D, which according to the catalog of pigments no. 24 of Degussa AG, page 12, is given by means of D = 2-log (R) giving the reflection R in percentage. An ideal white lacquer with 100% reflection has an optical density D = 0. The index of thixotropy is clarified in the catalog of pigments no. 5 --- of Degussa AG, page 3. It is calculated from the proportion of the viscosity of the lacquers in cases of SG cut low (v.) And high (v2): index of thixotropy = v / v2 Example 1 : Four different soots were prepared by means of the oven soot procedure. The raw material for the soot was composed of different amounts of silicone oil (polydimethylsiloxane, CAS No. 63148-62-9). The technical properties of these soot are given in table 2.

Table 2: technical properties of the soot provided with Si The content of cents of the above stocks consists of the essentials of highly dispersed silicon dioxide. The soot 1 is a comparative soot with an ash content of only 0.1% by weight which was prepared without the addition of silicone oil to the raw material for the soot. The soots 2,3 and 4 contain approximately 12.14 and 16% by weight of silicon dioxide. Technical studies of the lacquers: The four soots of Table 2 were used for the preparation of black lacquers in a binder system of two components based on acrylate resins hydrolyzed with isocyanate as a hardener. A binder solution consisting of 60% by weight of Synthalan L3768 from Synthopol Chemie, Buuxtehunde in 98% butyl acetate was used to prepare the lacquers. The binder was a hydrolyzed acrylate resin with 1.5 wt.% OH groups. The binder solution was added with 45% by weight of soot in relation to the solids content of the solution. 80 g of this ground mass were dispersed for 5 minutes with a dissolving apparatus. Then 550 g of steel beads were added and dispersed with a Scandex disperser. The steel beads were then separated in a sieve and the lacquer preparation was completed by mixing more binder solution. By the dilution with more binder solvent the soot content of the finished lacquer was reduced to 5% by weight, in relation to the binder content of the lacquer. The lacquers were mixed with a hardener based on isocyanates (Desmodur N from Bayer) and applied to glass plates with a wet film thickness of 50 μm. In the dry lacquers, My, M0, gloss and opacity were measured. Table 3: Results of exams The results of the examinations in Table 3 show that the opacity of the lacquer is dramatically avoided with the help of the soot according to the invention. This allows a better dispersion of the soot. In addition, Table 3 shows a clear reduction in lacquer viscosity and thixotropy, ie reduction of viscosity at high cutting rates, by the soot according to the invention. These effects were unexpected since the separate addition of silicic acid, for example, of pyrogenicly prepared silicon acid, generally leads to high viscosity and thixotropy. The separate addition of silicon acid can have disadvantageous effects, such as, for example, a greater need for a binder or solvent and a fluidity of the coating. Example 2: Another series of six oven soots with different silicon contents was prepared. The results of the technical examinations of the soot are shown in table 4. The starting soot, soot 5, was prepared without the addition of siiicone oil to the soot raw material. Its ash content of 1.22% by weight is based essentially on potash (calcium carbonate) which is added to the soot raw material to modify the structure of the final soot. The additional ash content of the soot from 6 to 10 is caused by its content of silicon dioxide.

Application technical examinations The six soots of table 4 were used for the preparation of black lacquers in an aqueous binder system (polyurethane dispersions, 30% by weight of polyurethane, in relation to the weight of the disperses) and in a binder system. two components (Synthalan LS768 in 98% butyl acetate). The lakes were prepared analogously to example i. The results of the technical examinations of the lacquers as well as the rheological behavior of the lacquers are shown in Table 5 (aqueous binder system) and 6 (two-component binder system). With an increasing content of silicon the depth of the color Mr is improved. This effect depending on the lacquer binding system used is expressed more or less strong. From this, the soot stability was also improved by means of the silicon content, which is expressed by means of a higher value (Mc-My), this is a greater proportion of blue in the color measurement. As shown in tables 5 and 6, viscosity and thixotropy are improved by the use of soot containing silicon. With a higher silicon content both values are reduced. It should be noted in particular that the reduction of the Thixotropy Index in the aqueous system depends on the silicon content) see table 5). With a higher content of silicon, not only the viscosity is reduced, but also the viscosity variation when the cutting cases are modified (index of thixotropy). By this property the soot according to the invention is suitable for combination with flake-like pigments such as pearlescent pigments and aluminum flakes, and facilitates their parallel orientation in the coating layer. The low index of thixotropy prevents that after applying the lacquer immediately increase the viscosity and that limits the mobility of the pigments in the form of plates in the still fresh lacquer. Table 6 shows the flotation behavior also observed in the preparation of a gray lacquer with a weight ratio of titanium dioxide to soot of 100: 4. In the gray lacquer in the starting soot (soot 5) a marked difference in the optical density is observed (the titanium dioxide floats). With a higher silicon content, the difference in optical density between the rubbed and non-rubbed paint surfaces is reduced.

Table 4: Technical properties of the soot gifted with SI Table 5: Technical properties of the l cage in aqueous systems It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the products to which it refers. Having described the invention as above, property is claimed as contained in the following:

Claims (7)

1. CLAIMS l.- Lacquer containing a lacquer and pigment binder system as a pigment, characterized in that the soot contains 0.1 to 30 by weight of silicon, calculated as silicon dioxide and in relation to its total weight.
2. 2. Lacquer according to claim 1, characterized in that the lacquer binding system is a binder system containing solvent.
3. 3. Lacquer according to claim 1, characterized in that the lacquer binding system is a binder system containing water.
4. 4. Lacquer according to claim 2 or 3, characterized in that as additional pigment contains titanium dioxide or a color pigment or mixtures of pigments.
5. 5. Lacquer according to claim 2 or 3, characterized in that it additionally contains at least a pigment in the form of flakes.
6. 6. Lacquer according to claim 5, characterized in that the flake-shaped pigment is a pearling pigment, aluminum flakes or mixtures thereof.
7. 7. Lacquer according to claim 1, characterized in that it contains 0.01 to 2% by weight of nitrogen. 8. - Printing ink containing a lacquer system and soot as a pigment, characterized in that the holli contains 0.1 to 30% by weight of silicon, calculated as silicon dioxide and in relation to its total weight. . - Printing ink according to claim 8, characterized in that as additional pigment contains titanium dioxide or a color pigment or pigment mixtures. 10. - Printing ink according to claim 8, characterized in that it additionally contains at least one flake-shaped pigment. 11. Printing ink according to claim 10, characterized in that the flake-shaped pigment is a pearling pigment, aluminum flakes or mixtures thereof. 12. Printing ink according to claim 8, characterized in that it contains 0.01 to 2% by weight of nitrogen.