DD227430A1 - MOLDING MATERIAL FOR CERAMIC WORK PROCESSES - Google Patents

Abstract

The invention relates to a mold material for ceramic working method with high permeable capillary action, which corresponds at least to the properties of gypsum, with respect to the mechanical strength by itself or in combination with a carrier material has a multiple of conventional working forms. According to the invention, a solid mixture consisting of hydrophilic and hydrophobic materials and a pulverized thermoplastic is mixed with the self-curing binary combination for organoglass, water and a dispersing agent and processed.

Description

runs exothermic. The amount of water that was not temporarily absorbed by the filler and the solvent is placed in a gas phase that must be absorbed by the surrounding mold material. Conveniently, this is porous and slightly enriched with water. At the mold interface, the condensation of this gas phase and thus the transport into the surrounding mold material takes place. This moisture leakage and thus the formation of the new capillaries promotes the hydrophobic filler. The exothermic reaction also causes the thermoplastic to soften and form a continuous skeleton after completion of the reaction. It is supported by the formed organoglass. The amount used of the organoglass portion is chosen so that no smooth dense surface of the working form can form. After a drying process, the working form is ready.

Further improvements of the solution according to the invention have been achieved by mixing and activating all solid components of the material combination beforehand in corresponding mills and thus subsequently following with the liquid components a normal mixing and casting process similar to the gypsum-water mixture. Furthermore, a simple shaping is achieved by a mold half z. B. for a Flachgeschirrarbeitsform for a tact line at the same time shaping but also working form carrier material. Very well proven is a lightweight material made of foamed polyurethane in a mold. To form a positive connection, a previous roughening is required. The advantage of this layer system is in addition to a lower weight and a lower material usage of the combination of materials according to the invention in the constant reuse of this carrier material by separating the porous working layer and re-casting the same. The frequent use ensures a considerable cost reduction. This is also the first time that working forms for ceramic work processes can be repaired. On the other hand, the heat-storing support material supports the porous molding material in the short-term and complete abandonment of the amount of water absorbed in the shaping process. The water absorption capacity of the working mold can be controlled by forming a proportion of activated filler from the decomposition product of SiO ₂ , the hydrogel. This makes it possible to produce casting molds in particular. To further increase the creep properties in complicated forms, a small proportion of the mineral combination bentonite in activated form is mixed in addition to the dispersant.

The multiple life of application forms associated with the use of the invention over those of gypsum material with high contour fidelity results in an increase in labor productivity in the mold making manufacturing areas and a reduction in downtime of the machine systems. Shelf storage reduces to normal levels and helps to reduce required shelf space.

embodiments

The invention will be explained below with reference to exemplary embodiments.

Examples 1 and 2 are preferably applicable to lathes and roller working forms on bars, 3 for molds, 4 for static and isostatic pressing, and 5 for die casting. Based on the parts by weight the following results: Example 1: 10 ... 18% ground dry porcelain mass 15 ... 25% talcum 15 ... 20% KaloplastR 3 ... 5% polyethylene 30 ... 40% methyl methacrylate 10 .. .15% water 1% dispersant

Example 2: 10 to 15% ground dry porcelain mass 3 to 5% hydrogel 2% bentonite 15, 25% talc 15 to 20% Kaloplast® 2 to 5% polyvinyl chloride 20 to 30% methyl methacrylate 15 ... 20% water 1% dispersant

Example 3: 8 to 12% ground dry porcelain mass 5 to 8% hydrogel 2% bentonite 10 to 20% talc 15 to 20% kaloplast

1 ... 4% polyvinyl chloride 20 ... 30% methyl methacrylate 15 ... 20% water 1% dispersant

Example 4: 8 ... 12% ground dry porcelain 3 ... 8% quartz flour

2% bentonite 15 ... 25% talcum 3 ... 5% polyethylene 20 ... 25% kaloplast R 30 ... 40% methyl methacrylate 10 ... 15% water 1% dispersing agent

Example 5: 10 to 15% ground-dried porcelain mass 3 to 5% hydrogel 15 to 25% talc

15 ... 20% Kaloplast® 5 ... 8% polyethylene 20 ... 25% methyl methacrylate 15 ... 20% water

1% dispersing agent

Claims (5)

Invention claims: 1. mold material for ceramic working methods with high permeable capillary action, characterized in that a solid mixture consisting of hydrophilic and hydrophobic materials and a powdered thermoplastic mixed with the self-curing two-substance combination for organoglass, water and a dispersing agent and processed. 2. Mold material according to claim 1, characterized in that the hydrophilic solid fractions are activated dry porcelain masses, hydrogel and bentonite. 3. mold materials according to claim 1 and 2, characterized in that the hydrophobic solids are talc and quartz powder. 4. mold material according to claim 1 to 3, characterized in that all solids are premixed in a mill and then combined and mixed with all liquid portions simultaneously. 5. mold material according to claim 1 to 4, characterized in that this is brought into positive connection with a dense substrate. Field of application of the invention The invention relates to a mold material for ceramic working method with high permeable capillary action, which is used individually and in combination with other materials in the crockery, decorative ceramic and ceramic construction, but can replace existing materials in other industries. Characteristic of the known technical solutions For ceramic work processes, which are based on working forms of a microporous permeable material, such as casting, die casting, screwing, rolling, molding and the static and isostatic pressing of plastic masses, gypsum is mainly used. As before, this cheap material impresses with its rational processability, tolerance and contour fidelity, its quick substitutability and, above all, the high water absorption and release capacity rarely achieved by other materials. The latter is caused by capillary forces that withdraw moisture under normal pressure and temperature conditions and release moisture when the temperature or pressure increases. Different varieties of gypsum grade can improve the life of these forms of work. In general, they are subject to rapid mechanical and thermal wear. To increase the strength z. As synthetic resins and or urea compounds mixed. The results in terms of skeletal stabilization in the mineral are usually at the expense of porosity and thus to reduce the desired properties described above. In addition, these additives reduce the roughness of the surface of the working forms, the z. B. when using the roller method to avoid textures is required. It can be deduced from this that all types of incorporation into the mineral structure of the gypsum have only slight advantages and will therefore find little use in the ceramic industry. The creation of working forms, with the plaster-like properties and, in addition, high mechanical and thermal resistance, requires the development of materials of completely different composition. In DE-OS 2104080 a porous absorbent working form of reaction sintered silicon nitride is described. A similar result should be achieved from the application of DE-AS 2403835. The mold material is a wear layer of porous sintered steel is placed at the most abrasion-prone locations. Shapes made entirely of sintered metal have also been used. In DWP 81 701 a material is described, which is mixed from a mixture of quartz, feldspar, corundum and metal powder with a thermosetting or thermoplastic plastic. This material is deformed under pressure and thermally cured. The DWP 86587 includes a mold material based on stabilized, porous and powdered PVC. A mold with a porous structure made of plastic and filler material is shown in DE-OS 1 683 803. The filling material consists of Schamottekügelchen formed by spray drying, sintered isolated and soaked in a thermosetting plastic to fill the pore space. The use of diatomaceous earth as a filler is the subject of DE-OS 1 584 485. Although all material combinations for use as work forms meet the requirement of higher mechanical strength, but in no way achieve the water absorption capacity of the plaster by capillary action. The results are 3 ... 4 times lower. Only when using these materials for Schlickerdruckgießverfahren the water passage can be increased. In order to maintain the capillary action of the gypsum, but to reduce the mechanical wear at the working mold interfaces, gypsum coating materials have been developed for the ceramic forming process on the one hand and another material for the machine receiving part on the other hand. In the DWP 142433 this two-component combination consists of gypsum and thermally pressed PVC. DWP 156955 proposes gypsum and gray cast iron. Object of the invention For ceramic work processes such. As the casting, rolling and pressing is deriving the particular form of work from a combination of materials, since with respect to the permeable capillary at least the same values as gypsum and with respect to the mechanical strength of a multiple of conventional working forms. The production of the molds should be achieved if possible by casting a comparative mass. Explanation of the essence of the invention The invention has for its object to develop a new material for work forms, which can be used for all ceramic work and meets their specific requirements. According to the invention, a proportion of ground or activated filling material is first homogenized from one or more components having a high water absorption capacity, with a two-substance combination, self-hardening to organoglass. In this mixture, another filler with hydrophobic surface effect and water is added. Finally, a small amount of a powdered thermoplastic is added. The homogenization of this combination into a pourable mass can be improved by means of a dispersing agent. The reaction of the system