DE1571466A1 - Process and device for the production of plasterboard and molded articles - Google Patents

Description

.Method and device for the production of panels and moldings from plaster of paris The invention relates first to a method for the production of panels and moldings from plaster, panels and moldings on gypsum-based are produced in a conventional manner in such a way that the plaster is mixed with water in order to its hydration, also known as setting, to enable and to enable the formation of a shaped body. The water addition9 based on the gypsum weight is 75% and above * The gypsum only needs a small part of this water to set, the excess water is partly removed again from the not yet set molding mechanically and / or dried out. The amount of water to be removed in this way is three or more times the amount required for setting. To achieve certain material properties, especially mechanical ones, such as strength, elasticity, etc.9 and to control the production process at the moment, additives or materials that go into the material are added to the plaster before or during irrigation. They can be mixed with the plaster in the dry additive; But they can also be dissolved or dispersed in water and mixed with the gypsum mixed with water; they can also be inserted or pressed into an applied, pre-formed binder material which already contains other additives. Furthermore, the binder mass can be applied to these additives or incorporated into them, if necessary with the use of mechanical aids. additions Others / turn, especially flat more or less rigid materials, a1.a can serve as inserts or top layers. These and also difficult-to-penetrate additives and certain production processes require a layered working method and formation of the molded bodies. In the known processes, the shaping is generally done after mixing the settable material by discharging it into molds and is improved, for example, by vibration, smear and distribution devices, etc. Thereafter, the mechanically removable excess water can possibly be removed by centrifugation or by suction, eating etc. are brewed out of the molding, which is then brought to set and dried.

Numerous methods are known that relate to special forms of training refer to the procedures generally described above, such as to the use certain settable materials, mixtures of settable materials, type and Way of adding certain additives, pre-draining, shaping, curing, Manufacturing method, etc.

For example, small-area plasterboards and moldings were specified, which for architectural purposes as decorative panels, as acoustic panels, for Cladding and used as composite panels and structural elements for partition walls will. The production takes place in each plaster of paris with water in a certain ratio, e.g. with a water factor of 100.1> .4a water based on the amount of gypsum, in batches precisely dosed and stirred and the pulp is poured into molds and then stripped off. The plaster of paris hardens and the set, moist plates and moldings are removed from the mold and dried. Partly become the plaster of paris or the Mixing water or additives specific to the gypsum paste, such as setting retarders, loose Glass fibers for strength reinforcement, etc., added; also can be in the form or Inlays can also be made in layers in dexi-poured plaster of paris, such as e.g. glass fiber fleece jute strips or metal fabric, which also results in a higher Intrinsic strength of the building is achieved. These panels are required by the Individual production and the use of relatively expensive additional materials expensive and only limited use.

For large-scale cladding purposes, a Cardboard-coated plasterboard is used as a so-called dry plaster, it is used on continuously running production lines produced by placing on an endless cardboard web, the edges of which are folded upwards, gypsum paste auflaufeng this spread and of a second cardboard web is covered, this thus obtained Pormling runs through a roller smoothing part is cut to length after the gypsum slurry has hardened, i.e. cut into pieces and dried the individual plates. The feature-bearing The element of this plate is the relatively expensive special cardboard. However, this one is very susceptible to Moisture, under the influence of which the processed Plates warped, furthermore against mushrooms and fire. The low strength of the Gypsum core makes processing difficult, especially the edges.

Another method * has become known which is also the Production of large-scale plasterboard continuously enabled and that will be the Gypsum fibers, preferably cheap paper fibers, added homogeneously * To a To achieve intermixing, a highly aqueous solution must be made from which sucked out a thin layer of material with the help of a continuous vacuum sieve will; this layer of material is wound on a roller and a layered molding is formed in the desired strength.

The present invention now relates to a method for production of molded bodies, in particular of plates or the like. made of plaster, through which on more rapid and cheaper way almost dry moldings with better or at least the same mechanical properties can be obtained.

In the method according to the invention, a molding made of calcined plaster of paris mixed with water is allowed to set and then dried. Preferably, only the water necessary for uniform setting is added and - indeed - best in an amount of 15-25 % based on the weight of the plaster of paris, powdery or homogeneously finely dispersible, malleable additives such as clay, raw plaster, fibers and shavings of all kinds synthetic resin powder hydrophobing agents, Parb-9 fire-retardant agents, plastic chips, etc., can be mixed in with the dry plaster as a mass and sprinkled with it, or the molding can be formed from the mass, difficult to mix in or by itself separating additives, such as felting fibers, etc. or the above-mentioned powder-like additives can be blown -sprayed-strewn or poured separately or simultaneously into the binder falltrom or -scatter sheet and thus form the scatterg or the bindable material can be in the Falletrom or scatter arc of these additions are interspersed, with an underpinning during this Vorga ngs or takes place in the formation of the molding. It is possible to achieve an uneven design in the scattering cross-section, for example in the form that the outer layers are more strongly enriched with the strength-increasing additives.

Non-scattering, matting, lanpfa-se -: # - ige or fleece-like, porous, flat, more or less stiff materials as additives or inlays, such as carded fleece, warped or blown veils, wire mesh, etc. can be interspersed with the bondable material by like run into the downdraft or scattering arc of the settable material at the top, placed on mold surfaces and penetrated by the settable material6 Little to non-porous, flat, more or less rigid materials or materials such as paper, cardboard, veneer, metal or plastic foils, cloths , Isolier- or Kunststoffl "lar'14, -, en etc., can be inserted in the middle or in the outer zones or serve directly as surface reinforcement, or cover layers, whereby the adhesiveness of the binding agent is used and by moistening the contact surface 'or through Use of adhesives can be increased.The formation of the independent molded body can also be layered in itself be carried out from layers of the same or different structure and / or composition. The setting moisture can also be applied in layers. The moisture introduced can contain various additives, dissolved or finely divided, such as setting agents. Schleunigerg -verzögererg water repellants, dyestuffs, hardeners, etc. The scattering, spraying or pouring, etc. (hereinafter referred to as scattering) of the settable material described under 1 can be carried out by powder scattering devices, e.g. by a continuously discharging conveyor belt, which applies the settable material drop a continuous, faster or slower working belt, or back and forth going back and forth in layers to form a molding or can be moved continuously or discontinuously o The molding can also be formed in layers by several scattering devices arranged one behind the otherg furthermore by air spraying, vibrating sieves, scattering brushes or rollers, etc. a more or less uniform shape formed in the (-isigen scattering) can be leveled, e.g. by distributing, smearing, leveling or grinding devices, shaking or vibration, etc. Mass are mixed in and the discharge can take place together, as described above.

Difficult to mix in, separigre-nd-ö additives can be used at the same time or separately by spreading devices (depending on the type of additives) in the Downstream of the settable material are interspersed; the reverse can also be done Flat, porous or non-porous materials can be used in the binder sheet let in or deposited, e.g. by hand, of such materials forming machines, such as carding or whirling machines running down from rolls or reciprocating magnetically or electrostatically or by vacuum holding Transport devices, etc.

The moisture can also be sprayed in and on by spray nozzles or. Rows of spray nozzles take place, b - we by devices such as are known, for example, from the painting industry. It is also possible to apply water-based carriers, such as water-soaked Ge webefilze to the settable material, which are stretched in a frame in the case of a discontinuous working method or used continuously in the case of continuous over rollers or the press belts of a roller press Formlings can be made - aii-f - endless, continuously or rhythmically continuously moving, circulating conveyor belts, in mold frames or in molds. The pressure treatment can take place in continuously working Fresseng vibration presses, rhythmically working presses, stack presses, single or multi-daylight presses, etc.

In order to meet the demands of the construction industry for a rationalization of the interior fittings and the production of molded parts, in particular through the inexpensive production of large-area plasterboards with high inherent strength and other excellent properties, the task of the previous work was to develop a process that would allow this under the special circumstances of the The properties of Gipsesq make it possible to hydrate and set and largely eliminate the previous disadvantages. As already mentioned, the previous processes have in common and this was previously considered inevitable that the plaster of paris must be mixed with a relatively high excess amount of water in order to enable proper hydration or crystallization and setting and to be able to make a shaping, The objective method of dry molding of the plaster and the addition of practically only the water necessary for setting, completely new conditions were created in the field of plaster processing. These differ significantly from the previously known standards about the setting process and the behavior of the plaster of paris during its hydration or crystallization. Until now, excess water had to be removed in a complicated manner after the gypsum slurry had been mixed with any additives, e.g. voluminous fibers, or after it had been formed, e.g. by vacuum or centrifugation, if a reduction in the pore space was required for reasons of strength. The simple way of pressing for dewatering and compressing the molding compound was not possible due to the plastic loosening of the molding compound. The problem of continuous compression molding was extremely difficult and costly to solve. A pore space was also created according to design (Jes Ubc # rsciiii12wassers, which significantly reduces the F (-stj (, lheit (.) Due to the process in question, there is no free pore space, or only extremely less, since there is no excess water In addition, any degree of compression is possible through compression and thus an internal connection of the structure, especially when using additives . Due to the low flow tendency of the ralativ dry even complex shaped mold body, for example, can be obtained corrugated plates by scattering of the molding material in different nivell molding formed. also, a flat formed molded article can be post formed as desired. in addition are the drying cost is lower, since almost no excess water is dried musto disadvantages due to the adhesion of the plaster of paris as Br ei and the soiling of the machines occur to a much lesser extent than with previous manufacturing processes. In previous processes, if additives had to be mixed in homogeneously, for example voluminous additives or additives very different in their specific weight to gypsum, an increase in the water factor or a complicated technical process was necessary. The setting time was added as an essential factor, which begins at the moment the plaster is mixed with the water and extends over a relatively short period of time and thus offers little mobility.

Mixing additives with the dry, powdery plaster is easier to carry out than mixing with watery gypsum paste, indifferent whether the addition to the dry gypsum mass before scattering, when scattering the individual Materials or takes place during molding. Are flat, porous additives is also sprinkled with the plaster of paris or the bindable previously mixed material good penetration possible. The mixing process is not temporal Limits are set, as the water is only added during or after molding and the setting starts at that moment.

Completely new conditions have also arisen during the setting processes for the plaster of paris. Up to now, this started practically at the moment the plaster of paris was mixed with the setting water and extended in time to the processes of underpinning, admixing of additives, pre-dewatering, discharge and final shaping. This required the addition of retarding agents and sometimes also accelerating agents in order to accelerate the setting when it was finally allowed to take place despite the retarding agent. By adding the setting water during or after the shaping, this problem is completely eliminated. The aim is to accelerate the setting process immediately9 which is arbitrary, e.g. can be shortened to a few minutes. After this short setting process, drying can take place immediately, which offers significant advantages, particularly in the case of continuous production. It is known from practice and the literature that the addition of retarding agents, especially in the case of a small overdosage, causes a high drop in strength, as does the simultaneous addition of accelerating agents. For example, WC Ridell stated in his investigations into the influence of organic and inorganic additives on the setting behavior, the solubility and the tensile strength of gypsum (CaSO 4-112 H20) in 2Rock Productsll Issue October 1954 that the addition of 0.75% raw gypsum (CaS0 V 2 H 20) the setting time is reduced from 30 minutes to 10 minutes, but the compressive strength drops by 5%. In tests in the present process it was found that an addition of 10% raw gypsum, apart from a substantial acceleration, has no effect on the workability, that even an increase in strength occurs can.

1 to 5 of the drawings show schematically various devices for carrying out the method according to the invention; these devices are described in more detail with reference to the following examples. These examples are intended to illustrate the present invention in more detail, without this, however, is to be limited thereto, Example 1 (see Fig. 1) Dry gypsum (CaS0 40 112 H 20), and optionally (CaS0 4) through a powder scattering device 1 to a laterally folded cardboard web 4 scattered. Approx. 25% water and accelerator (eg 2% K2S0 4 based on gypsum) are sprayed into the falling stream of plaster of paris through a row of nozzles 2. Immediately thereafter, a second sheet of cardboard 5 is placed. For better adhesion of the cardboard to the plaster of paris, the bearing surfaces of the cardboard can, for example, be sprayed beforehand with water or with an adhesive solution through the nozzles 6 and 7. Compensating and cutting devices are no longer required; Brief pressing of the cardboard web, e.g. by pressing rollers 8, is sufficient because the strongly accelerating additive causes immediate setting, while according to the conventional method, the wet-mixed and discharged material is slowly set, which is difficult and expensive to dry through the cardboard layers. In addition to the simpler and significantly shorter design of the system, the drying costs in the case of the method in question are extremely low. The higher rigidity, at the same time higher strength, enables this panel to be used especially for free areas without much support, especially as a shuttering panel in ceiling constructions, etc. *, as well as for all uses previously known for plasterboard with cardboard cover layers. EXAMPLE 2 _ (see Fig. 2) Above a streuzoney the z * B. 30 cm wide, the gypsum spreading device 1 is arranged, which has, for example, a vibrating sieve lb, the box of which is continuously fed with gypsum hemihydrate by a screw la. Raw plaster of paris, contained, Furthermore, dry paper fibers are dosed by volume from a bunker by a conveyor belt, e.g. by a lifting-off hook knife, which throws back the excess fibrous material, discharged and spread by a discharge roller into a chute and via a distribution roller at an inclined angle (spreading device 3) is narrowed and so, for example, the outer layers have a double concentration of fibers in the air medium. The scattering can take place, for example, on an endlessly revolving conveyor belt 10 with side delimitation strips and guide plates. With the help of the vibrating sieve lb, a uniform amount of gypsum falls into the scattering zone of the fibers and mixes with it at the moment of simultaneous exposure. The setting water is also sprayed in at this moment from the nozzles 2, in an amount of, for example, 25% based on plaster of paris. The setting time has been significantly reduced by the beach acceleration * The formed molding continues to set on the conveyor belt 10, for example, 4 minutes and is then gradually compressed in a through- feed press 8a and then compacted, for example over a minute at 1 kg / cm 2 the ligated endloseg form Linggenberg can immediately be shared, stacked, and the plates dried and undivided au.f-_Äullen pass through a drying channel (9), the thickness of the plates, for example of 4 50 mmg Arbeitsgeschwindigkeit.des by the conveyor belt, as well as the gypsum and fiber spreading machines adjustable as required; also the fiber content due to the speed of the gypsum or fiber spreader. The strength properties of this board are around 120 kg / cm 2, it is elastic, resistant and easy to process and particularly suitable as an interior building board, e.g. for partition walls, etc. EXAMPLE 3 (see Fig. 3) 70% plaster containing 10% raw plaster as accelerator and 34 Asbestos fibers are mixed in, for example, in a trough 11 and transported discontinuously into a storage container 12. A vertical discharge nozzle 13 meters quantities which are poured discontinuously into a mold 149, for example into a deodorant plate with a profile, and then distributed. These shapes are moved rhythmically on a belt 10 or rollers. During the next downtime, after the distribution of the gypsum-asbestos mixture, the Aq # spraying of the binding water can be carried out, during the following a compression, e.g. by a 1- tier press 8b, which opens before the movement and after the Stills.tand closes.

After hardening, demoulding and drying (9) comprises a plate which has excellent mechanical and fire retardant properties particularly aufweisto Example 4 is obtained (see Fige 4) In simple flat shape frame 14 or mold box 15 is inserted, for example, glass fiber fleece. This is penetrated by plaster of paris through a back and forth spray device 1 arranged above it. The water is introduced by placing water-soaked supports stretched in a frame, for example a fabric felt 16. The molding frame 14 is passed on to a stacking press 8e, which cures the molding at, for example, 0.5 kg / cm 2 pressure. The carrier 16 can then be peeled off again from the molding. The formation of profiled or perforated plates with extensive breaking strength is particularly simple. If thicker panels are required, multiple layers of veils and plastering can be applied.

The board, e.g. 2 - 8 mm thick, has particularly high strength values, of approx. 200 kg / cm 2 , and can be used for lighter constructions or as a semi-material, e.g. in the furniture industry for interior design, etc.

EXAMPLE 5 gearbeitett with a continuous production line as shown in Figure 5. This continuous production line comprises an endless carrier band 30 to the roller 31 and an initial end roller rotates a 32nd Further rollers 33 and 34 are arranged at a central point of the endless carrier belt 30. The charging device for the individual raw materials is arranged next to the start roller 31 and is denoted by 35. A press is formed between the rollers 33 and 34 and is designated quite generally by 36 . Next to the end roller 32, finally, there is arranged a cutting device 37, the charging device 35 comprises a Papierfasersilo 38. At this Papierfasersilo 38 downward then a paper fiber bin 39 and at the lower output of the paper fiber bunker 39 is a fiber scattering brush 40. Further, the charging device 35 comprises a gypsum bunker 41 which is fed at its upper end by a plaster screw conveyor 42. A metering roller 43 is arranged in the plaster bunker 41 at the middle height. At the lower exit of the gypsum bunker 41 there is a gypsum spreading roller 44 at the same level as the fiber spreading roller 40 of the paper fiber bunker. A chute 45 is formed below the fiber brush and the plaster brush, which converges downwards. A vortex roller 46 is arranged at the lower exit of the chute 45. The vortex roller 46 is located above an intermediate conveyor belt 479 which runs over rollers 48 and 49. A leveling roller 50 is arranged above the intermediate conveyor belt 47. Next to the end of the intermediate conveyor belt 47 there is a discharge roller 51. Also next to the end of the intermediate conveyor belt 47, spray pipes 52 are arranged. Unless otherwise indicated, all parts of the far described Beschc # extending effect device 35 over the entire width of the strip 30o The press 36 includes, besides the above-mentioned rollers 33 and 349 rollers 53 and 54 around which an endless Freßband 55 runs. The endless press belt interacts with the carrier belt 30 in the area of the press. The two belts 30 and 55 are tightened against one another in the area of the press 36 by pressure bodies 56 and 57, respectively.

The cutting device 37 comprises a cutting knife which extends over the entire width of the web, that is, over the entire width of the carrier tape 30 #.

The mode of operation of the continuous production line described so far is as follows: From the silo 38 , paper fiber arrives in the paper fiber bunker 39 and is brushed off at the lower end of the paper fiber bunker 39 by the fiber brush 40 from the fiber column standing in the paper fiber bunker and thrown into the chute 45. Gypsum is thrown through the screw conveyor 42 is conveyed into the gypsum bunker 41 and forms a column in this gypsum bunker 41. The amount of gypsum which permeates the gypsum plaster in the unit of time is determined by the speed of rotation of the metering roller 43. The plaster of paris is thrown from the plaster bunker 41 into the chute 45 by the gypsum loyalty brush 44 and mixes there with the paper fiber material that is thrown by the fiber spreading roller 40 into this chute. A whirling roller 46 at the lower end of the Fa-11 shaft 45 still promotes the mixing. The mixture coming from the chute is then placed on the intermediate conveyor belt 47 and conveyed by it in the figure from Linlisnach right. On its conveying path, the gypsum-paper fiber mixture carried by the intermediate conveyor belt 47 runs under the leveling roller 50 and finally falls down onto the carrier belt 30 at the end of the intermediate conveyor belt 47 on the right in the figure. The discharge roller 51 ensures that it falls evenly. While the mixture of plaster of paris and paper fiber falls from the intermediate conveyor belt 47 onto the carrier belt 30 , the falling stream is sprayed with liquid, which is sprayed through the nozzle spray tubes 52 into the path of the plaster of paris fiber mixture. A layer of moistened gypsum-paper fiber mixture is thus formed on the carrier tape 30. This layer runs into the press 36 and is pressed there to form a strand of panels. Der.Plattenstrang has the opportunity to dry up to the cutting device 37 , then it is cut into individual plates of the desired size. The cut plates can be further dried in a subsequent drying device The production line described is made of stucco, in accordance with, d £ -n-1) lk regulations 1168 ; this stucco corresponds chemically to the composition GaS0 40 1/2 H 2 0. The accelerator used is potassium sulfate K 2S0 4. The paper fiber is a material used which has been supplied in the form of waste paper bales in a Vorzerkleinerungemühle to shredded paper and then crushed in a Peinmühle again, the dry base mixture of plaster and fibrous material is adjusted so that it 90 Gewo% gypsum and 10 wt.% Contains paper fiber. Based on this dry basic batch, 25% liquid is added (again based on the dry weight of the basic batch); this liquid already contains 5% potassium sulphate based on the dry weight of the basic mixture. The running speed of the carrier belt is 4 m per minute. The setting time is considered to be the time during which the resulting strand of panels runs on the conveyor belt 30 @ With a center distance of 25 m between the rollers 31 and 32 , the time available for setting is 6 minutes. Of this time, 3 minutes are allotted to the run through the so-called Vorbindezo.nog that is the zone before entering the press 36. The throughput time through the press 36 is 1 minute Plate or similar

Becomes 10 mm thick . A regulation within wide limits between eao 45 mm board thickness is possible.

After leaving the conveyor belt, the strand of panels continues to run on a roller conveyor until the cutting device is reached. The cutter is loading vorzugt a .-- to the plate strand at the same speed revolving saw that when the Platter strand is sawn through quickly zurückk.ehrt each time to their initial position and for the next record from the strand sawed in the drying device, the plates during a Continuously dried hour, the plates show a breaking strength of 120 kg / cm 2 and an apezifinehes weight of 1 kg / dm., 6

Claims (2)

P atentans p r ü che method for producing a molded article, in particular a disc on the basis of gypsum or other of sulphate mineral binders such as anhydrite and sulfate slag cement, by setting blank of a corresponding shaped product with water versetzten'Bindemittel and then drying this -_, FOTM -li-ngs, characterized in that the binder is brought into a form essentially dry as a powder or grain and is moistened at the same time with or after the introduction. 2. The method according to claim 1, characterized in that essentially only the amount of water necessary for uniform setting is added. 3. The method according to claim 1 and / or 2, characterized in that at least for use of gypsum water in an amount of 15 - 25%, based on the weight of the gypsum, was added. 4. The method according to any one of claims 1 to 3, characterized in that the not yet set molding is reshaped, preferably compacted by continuous or intermittent pressure. 5. The method according to any one of claims 1 to 4, characterized in that the water and optionally liquid additives are added by spraying the falling into the mold or the material already lying in the mold. 6. Method according to one of claims 1 to 5, characterized in that the water is added by steam treatment. 7. The method according to any one of claims 1 to 6, characterized in that the water is introduced in the form of additives which contain the water chemically or physically bound. 8. The method according to one of Anspri. 1, characterized gekennzeichriet "che to 7, wherein the moisture is intermittently introduced between successive layers. 9. A method according to any one of claims 1 to 8, characterized in that the water through zweitweilige contact one with water aspirated 10. The method according to claim g1, characterized in that the water is released from the water carrier to the molded article while the latter is pressed against it. 11. The method according to one of claims 1 to 109, characterized in that, l # t) eim the binding agent and / or the water reinforcing and / or 1 .. ", (ir (.) 1) hobierer) de and / o (ier fire-retardant and / or coloring and / or hardening and / or setting-inhibiting and / or setting-retarding and / 12. The method according to claim 11, characterized in that, in the case of additives which can be mixed homogeneously with the binder, in particular powder gene and / or short-z-fibrous additives, these are mixed with the dry binder before being introduced into the mold. 13. The method according to any one of claims 11 and 12, characterized in that in the case of water-soluble and / or water-dispersible additives, these are dispersed and / or dissolved in the water to be introduced for setting. 14. The method according to any one of claims 11 to 13, characterized in that in the case of additives which are difficult to mix with the binding agent and tend to separate, these are brought together with the binding agent immediately before or during the charging of the mold, preferably by sprinkling on intersecting litter paths, 15 . a method according to any one of claims 10 to 14, characterized in that in the case of flat additives they are inserted or laid between successive layers or at interfaces of the resulting molding. 16. The method according to claim 159, characterized in that in the case of flat and bulky additives, these are filled with binders and optionally other additives. 17. The method according to any one of claims 1 to 16, characterized in that the molding is formed in several layers of different structure and / or composition. 1.8. Process according to one of Claims 1 to 17, characterized in that it is carried out continuously with the formation of a shaped strand and that this shaped strand is cut into individual shaped bodies. 19. The method according to claim 18, characterized in that binders and / or additives and / or water are introduced into the resulting molding strand at different points spaced apart from one another in its direction of movement. 20. The method according to claim 19, characterized in that a surface coating sheet of the resulting molding strand is used as the molding surface. 21. Device for carrying out the method according to one of claims 18 to 209, characterized by a Pührungsflähe supply devices for binding agent, water and optionally additives and a drying device on this guide surface. 22. Device according to claim 219, characterized by a compaction device in the web direction in front of the drying device. 23. Device according to claim 22, characterized in that the compacting device is designed as a press,