DE3327336A1 - Process for producing waterproof tiles from gypsum, and casting mould - Google Patents

Abstract

Glazed tiles of gypsum have a considerably greater dimensional stability than those of ceramic or porcelain. They are at the same time rendered waterproof and are provided with the necessary strength factors by producing them from an aqueous suspension of alpha-gypsum hemihydrate, sulphate slag cement and aluminium sulphate and placing them into a tile-shaped mould, whereupon the suspension is defoamed during setting in the mould by vibrations, for example ultrasonically, and then released from the mould after the setting step and, if desired, are also provided with a surface coating. Glazed tiles having optimum strength and good water resistance properties are obtained in particular by introducing the suspension as part charges which have the same or different compositions. The properties relating to water resistance and strength are here particularly good if, in layer-wise production, a mixture of alpha-gypsum hemihydrate and urea/formaldehyde resin and/or melamine resin is introduced into the tensile zone and/or compressive zone of the tile. For implementation, a casting mould is used which is associated with a plurality of mixing vessels, in particular also for the resins and the alpha-gypsum hemihydrate. <IMAGE>

Description

The invention relates to a method of manufacture

of plasterboard tiles made of an aqueous slurry Alpha gypsum hemihydrate, sulphate cement and aluminum sulphate are made in one Filled in the casting mold, defoamed during the setting by applying vibrating tones, and demolded after drying and hardening and as a tile with a surface coating is provided according to the patent (patent application P 33 18 364.3). The invention relates to In addition, a casting mold for the production of tile panels, consisting of the base plate and a separable edge releasably connected to it, as well as upstream mixing containers with outlet.

The well-known tile panels are usually based on ceramics or made of porcelain. Such tile panels are according to the prior art after the briquettes have dried, they are prebaked at 100 to 12250 K. The bricks become firmer in the pre-fired state, but are still completely porous. However, they no longer soften when water is added because they have this property lost due to the thermal decay of the kaolin molecule. These bricks are then dipped in a glaze sludge that contains enough flux in addition to the raw mass contains, so that he in the subsequent Gutbrand at 1625 to 17350 K to one Glass coating melts.

For example, dolomite or feldspar are used as fluxes. At the Gutbrand the feldspar dissolves the finer kaolin and quartz particles with the formation of new silicates such as.

Mullite on.

The raw material required for the production of such tile panels, Kaolin is a very valuable raw material, the deposits of which are limited and which must be won in open-cast and partly in civil engineering. Kaolin is accordingly expensive, proving to be a disadvantage it turns out that such ceramic Substances have a relatively large shrinkage behavior during drying and Have burning process. The committee is therefore relatively large.

Attempts have already been made to use plaster tiles as well to manufacture. Plaster of paris is available in much larger quantities and falls also often used in chemical processes, but does not result in water-resistant tiles, which also have insufficient strength values. According to the main patent, it is now succeeded, from an aqueous slurry of alpha gypsum hemihydrate, sulphate slag cement and aluminum sulfate to manufacture a tile, the relatively low manufacturing cost requires and has sufficient strength properties with water resistance. These good strength values are due both to the composition of the aqueous Slurry as well as the even and safe defoaming by the applied vibrations. This process needs to be optimized.

The invention is based on the object of varying the method in such a way that that the water resistance and strength of the tile are targeted depending on the intended use can be influenced. In addition, one should be suitable for carrying out the process Casting mold are created.

The object is achieved according to the invention in that in the layer-by-layer Production of a mixture of alpha gypsum hemihydrate in the tension and / or pressure zone of the tile and ureaformaldehyde resin and / or melanin resin is introduced. This will increase the water resistance and the strength of the tile is decisively improved, with the special layer placed either in the tension zone or in the pressure zone or in both tension zones will.

Appropriately, a mixture with a resin content of up to incorporated at 42% by weight. This results in the aforementioned good strength and water resistance values achieved.

Surprisingly, it has been shown that it is sufficient, one right thin layer of alpha-gypsum hemihydrate and ureaformaldehyde resin or melanin resin to be brought into the tile. According to the invention it is provided that the mixture in a layer thickness of 1 to 3 mm is introduced.

A particularly good effect in terms of avoiding water sensitivity and the brittleness is achievable if a ureaformaldehyde trcondensate with a composition of 1 mole of urea to 1 to 2.5, preferably 1.5 moles of formaldehyde mixed with alpha-gypsum hemihydrate and then in the tensile and / or compression zone of the tile is brought. The precondensate with a composition of 1 mol of urea 1.5 moles of formaldehyde brings optimal values.

To further increase the mechanical strength, i.e. the pressure, Flexural and tensile strength, it is advantageous to influence the setting reaction in such a way that that first the ureaformaldehyde and / or melanin resin hardens. It affects Another advantage is that that is released during the condensation of the resin Additional water as reaction water for the setting reaction of the alpha hemihydrate can be used.

Such reaction control is advantageously achieved by that the setting reaction is delayed by adjusting the temperature and the hardening process is accelerated.

For this purpose, the urea formaldehyde and / or melanin resin is used after mixing with alpha gypsum hemihydrate at 300 to 400, preferably 3530 K cured. At the same time, as mentioned, with such a temperature setting or

- Delays the setting reaction of the alpha-gypsum hemihydrate.

Another possibility or an additional possibility of Influencing the reaction rate, especially the curing, lies in that according to one embodiment of the invention, the ureaformaldehyde and / or melanin resin is cured at pH 2.5 to 4.5, preferably pH 4. By choosing one of these The pH value can also advantageously reduce the water sensitivity of the cured Resin are reduced, so that there is a double effect.

A significant improvement in the relation of compressive strength to Flexural strength of the cured mixture is possible because during the mixture of alpha-gypsum hemihydrate and ureaformaldehyde and / or melanin resin for the Inorganic and / or organic fibers are added to the tensile zone of the tile. the Fibers of inorganic and / or organic nature influence the mixture positive, so that this much more favorable compressive strength in relation to Flexural strength reached. It is particularly useful to have a corresponding Laying fiber-enriched layer in the tensile zone.

A casting mold consisting of the base plate and a releasably connected divisible edge as well as upstream Mixing containers with outlet. The mixtures are poured over the mixing container with an outlet different composition at predetermined time intervals in the Poured into the mold, which either stands still or moves slowly and is applied with ultrasound or the like. on this way will already every single layer defoams, which has beneficial effects in terms of final strength Has.

According to the invention it is now provided that the pivotable outlet the mixing container is assigned an adjustable nozzle. With the help of the nozzle you can even very thin layers are specifically applied or evenly produced in the casting mold will. This applies in particular to those made from alpha-gypsum hemihydrate and ureaformaldehyde and / or thin layers consisting of melanin resin, i.e. 1 to 3 mm thick.

To influence the reaction speed of curing or the setting reaction is provided according to the invention that the base plate and / or the edges are designed to be heatable. This allows the filled in the mold Mixture can be influenced in a targeted manner in such a way that the desired time sequence with regard to the setting and curing process is achieved. This applies in particular, when the mixture is poured into the appropriately preheated casting mold.

Another way of controlling the reaction is that under which Traversing drive to arrange a movable heating. This heating is movable, to limit their extension below the travel drive.

Depending on the travel drive, i.e. conveyor system, it is also possible to use the Provide heating in the belt or travel drive, so as to ensure uniform heating to achieve the individual molds.

In order to achieve a uniform and therefore advantageous mixing of the as relatively thin layer of the mixture of alpha-gypsum hemihydrate and Ureaformaldehyde resin and / or Ensure melanin resin is it is advantageous that, according to one embodiment of the invention, a mixing container Mixer with associated storage containers for urea formaldehyde resin and melanin resin voralteitSW It is also advantageous to design the nozzle as a surface nozzle, so that the desired thin layer is precisely positioned within the tile will. The tension or pressure zone is depending on the design and shape of the tile at different positions within the tile or on the surface or on the floor. Regardless of this, however, the layer is applied exactly there where it belongs according to the intended use.

The invention is particularly characterized in that a method for the production of tiles made of plaster of paris, which in terms of strength and the water resistance is variable, so that much more optimal tile panels are to be produced with it. Since the reaction control is also used to control the curing or reaction process can be precisely controlled, is in this way a to achieve precisely adaptable tile panels for the intended purposes. The mold has been further developed so that it can carry out the individual process steps can easily run, so that the provided thin layer of particularly formed material is placed exactly where it is Purpose is required accordingly. The manufacturing process itself will only be slightly more complicated, but with improvements in water resistance and the strength are much higher.

Further details and advantages of the subject matter of the invention result in particular with regard to the casting mold from the following description of FIG associated Drawing showing a preferred embodiment is shown with the necessary details and individual parts. Show it: 1 shows a schematic representation of a device for the production of tile panels made of plaster of paris and FIG. 2 shows a tile panel, partially in section.

Fig. 1 shows a number of molds 1, 2, consisting of one Base plate 3 and releasably connected edges 4, 5, which have a displacement drive 16 with drivers 17 are assigned. About the driver 17 are the individual Casting molds 1, 2 first passed under the filling station by the traversing drive and then via the ultrasonic device 15, with the help of which the filling of the casting mold 1, 2 is defoamed.

A number of mixing containers 18, 19, 20, the number of which depends on the quantity of the individual layers to be produced Aligns tiles. The individual mixing containers 18, 19, 20 each have one the outlet 21 directed towards the casting molds. This outlet 21 has a closure 22, i.e. a valve with which the outflow of the mixture of alpha-gypsum hemihydrate, Sulphate cement and aluminum sulphate as well as the other substances are regulated and controlled can be.

Around the according to the procedure very thin layer of the mixture of alpha-gypsum hemihydrate and apply ureaformaldehyde resin and / or melanin resin evenly and quickly at least the outlet 21 of the mixing container 19 has a nozzle 37, which are preferably designed as a flat nozzle or

Surface nozzle is formed.

The individual casting molds 1, 2 have a heatable base plate and / or heated edges 4, 5. As shown in Fig. 1, the heating 38 arranged below the displacement drive 16 and is preferably also move with the traversing drive or separately.

This heating 38 can indeed be corresponding inlets Act in the traversing drive, i.e. in belt 16.

A separate mixer 39 is assigned to one of the mixing containers 19. This mixer is used to prepare the mixture of alpha-gypsum hemihydrate and Ureaformaldehyde resin or melanin resin. There are therefore storage containers with the mixer 39 for ureaformaldehyde resin 40 and for melanin resin 41 available. About the supply line 42, for example, alpha-gypsum hemihydrate, but also other material can be added such as the intended organic or inorganic fibers.

Claims (14)

Process for the production of waterproof tiles from plaster of paris and a casting mold Claims g method for the production of plaster of paris tiles, in which an aqueous slurry of alpha gypsum hemihydrate, sulphate slurry cement and aluminum sulphate produced, poured into a mold, during the setting by applying defoamed by vibrations, and demolded after drying and hardening and as Tile is provided with a surface coating according to patent (patent application P 33 18 364.3), characterized by the fact that when ordering in layers in the tension and / or compression zone of the tile is a mixture of alpha-gypsum hemihydrate and Ureaformaldehyde resin and / or melanin resin is introduced. 2. The method according to claim 1, characterized in that a mixture is introduced with a resin content of up to 42 wt .-%. 3. The method according to claim 1, characterized in that the mixture is introduced in a layer thickness of 1 to 3 mm. 4. The method according to claim 1, characterized in that a ureaformaldehyde precondensate with a composition of 1 mole of urea to 1 to 2.5, preferably 1.5 moles Formaldehyde mixed with alpha-gypsum hemihydrate and then put into the tension and / or compression zone the tile is brought. 5. The method of claim 1, claim 2, claim 3 or claim 4, characterized in that the setting reaction is influenced so that initially the ureaformaldehyde and / or melanin resin hardens. 6. The method according to claim 5, d a d u r c h g e k e n n ze i c h n e t that the setting reaction is delayed by adjusting the temperature and the Curing is accelerated. 7. The method according to claim 5 and claim 6, d a d u r c h g e k It is noted that the ureaformaldehyde and / or melanin resin after mixing is hardened with the alpha-gypsum hemihydrate at 300 to 400, preferably 353 K. 8. The method according to claim 5, characterized in that the ureaformaldehyde and / or melanin resin is cured at pH 2.5 to 4.5, preferably pH 4. 9. The method according to claim 1, d a d u r c h ge n n zei c h ne T eat with the mixture of alpha-gypsum hemihydrate and ureaformaldehyde and / or Melanin resin for the tension zone of the tile, inorganic and / or organic fibers be admitted. lo. Casting mold for the production of tile panels, consisting of the Base plate and a releasably connected divisible edge as well as upstream Mixing containers with a spout, that is, the swiveling one An adjustable nozzle (37) is assigned to the outlet (21) of the mixing container (18, 19, 20) is. 11. Casting mold according to claim lo, characterized in that the base plate (3) and / or the edges (4, 5) are designed to be heatable. 12. Casting mold according to claim lo, d a d u r c h g e k e n n z e i c h n e t that a movable heater (38) is arranged under the traversing drive (16) is. 13. Casting mold according to claim lo, characterized in that one Mixing container (19) a mixer (39) with associated storage containers (40, 41) for Ureaformaldehyde resin and melanin resin are connected upstream. 14. Casting mold according to claim lo, characterized in that the nozzle (37) is designed as a surface nozzle.