DE2129942A1 - Gypsum and Portland cement compounds that set with water and products made from them - Google Patents

Description

DR. R. POSCHENRIEDER

DR. E. BOhTrNER
DIPL-ING. Η .-. Ϊ. MÖLLER

Patent attorneys
8 MUNICH 8Θ '
Lucile-Gralin-Strafeie 38
Telephone 443755

Oasis 5284

KAISER GYPSUM COMPANY, Inc., 300 Lakeside Drive, Oakland, OaI. (7.St ₀ A ₀ )

Gypsum and Portland cement compounds that set with water and products made from them

The manufacture of plaster products such as plasterboard and plaster of paris, and also the manufacture of Portland cement products belong to the state of the art per se. There are very large amounts of these every year Materials made. In recent years numerous attempts have been made to to produce such products with a much lower density without reducing the strength. There is obviously a technical need for such lightweight products; for example the building bases no longer need so strong and cost-

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to be playful like those needed with heavier products. For this purpose one already has different ones Materials used such as expanded perlite in plasterboard, such as U.S. Patent 2,8Oj5,575 and expanded polystyrene beads in concrete products as described in U.S. Patent 3,247,294.

Albeit some improvements in the manufacture of lightweight gypsum and lightweight concrete products have been achieved, the known products do not yet provide the final solution to the problem mentioned For example, when cutting plasterboard made with perlite, the knives or saws become fast dull.

When using expanded or blown polystyrene beads several difficulties arise. The pearls tend to have a strong electrostatic charge, and as a result, they do not flow evenly out of storage bins and feeders, rather, they tend to stick to the side walls of the devices. Furthermore, the pearls float on the Plaster top layer and the cement paste top layer, which often leads to a high accumulation of pearls on the surface of the products. In addition, the need for water for the pulp increases when the pearls are used, and because of the volume that the pearls occupy. In addition, the finished products containing expanded polystyrene beads have the disadvantage that the beads, the a relatively smooth, non-wettable surface own, in the basic structure take up a volume,

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but without becoming an integral part of it. They do not or will not stick to the ground floor not bound to them and tend to burst during processing and later handling.

It has now been found that one can make of plaster of paris or Portland cement, which one - below explained in more detail - has added shredded or expanded polystyrene as an additive, with Water-bound products, namely gypsum products such as wall panels, strips, cladding, base panels, Can produce molded panels and plaster, as well as concrete products such as blocks, partitions and roof tiles that have significantly lower densities than comparable products made from masses without such an additive have been produced, the structural strength of the lower-weight products surprisingly not is seriously impaired.

FIG. 1 shows the overall system in the form of a flow diagram a plant for the production of gypsum wall panels using fiber-reinforced, expanded polystyrene aggregate again.

Figure 2 is a partial cross-section through a according to one embodiment product made of the invention.

Used as an aggregate from fiberized, expanded polystyrene added to calcined gypsum products or Portland cement, the water-set products which have been produced from such batches have a significantly lower density. The lower densities depend to some extent on the amount of the

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Aggregate that is incorporated. As has been found, even very small amounts, for example those down to 0.01 percent by weight, based on the total mass, are effective. The maximum amount of aggregate that one uses depends in a certain way on economic considerations. It has been found that up to 5 % can be incorporated without noticeably changing the strength of the end products. A gypsum wall panel of particularly good quality is produced by adding 2 to 3 percent by weight of the said aggregate to the mixture. With this mixture, wall panels can be produced that weigh about half as much as the known wall panels that are made without the addition of the aggregate.

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fes, e.g. 0.50 g / dm (1200 pounds per thousand square feet) compared to 96.5 g / dm ^£ (2000 pounds per thousand square feet).

The aggregate used in the present invention is made entirely of expanded material Polystyrene that has been converted into a light, fluffy material through shredding or grinding. For example, an expanded polystyrene with a bulk density of approximately 0.0048 g / cm² to 0.024 g / cm² (0.3 - 1-5 pounds per cubic feet) are shredded, to obtain an aggregate, of which 70 percent by weight, preferably 85 percent by weight, through a 4-mesh sieve and from a lo-mesh sieve (meant mesh screens of the US standard screen series) are retained.

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Defiberized, expanded polystyrene aggregate, as it is used in the invention, can be made from polystyrene beads or foam, including the technical material generated in the company. As has been found, expanded polystyrene beads can be effective and economical for extracting the aggregate be shredded or ground. The beads in question for this purpose are in the United States patents 2,681,521, 2,950,261 and 2,744,291.

Contrary to the difficulties encountered with using expanded polystyrene beads, the aggregate used in the present invention easily and evenly through reservoirs and feeders. It can also be mixed directly and intimately into the aqueous slurry and does not show any Tendency to swim on the surface of the slurry. It is also quite surprising that the water demand, which increases when using expanded polystyrene beads when using the additive according to the invention is reduced. It appears as if the frayed material has some of the voids in the cementing mixture fills out and this creates a uniform, dense base mass that requires less water to be mixed in. This reduced water requirement brings the further advantage with regard to the processing of these materials with it that the drying stage is shortened accordingly or lower temperatures are used can. The fiberized material is ultimately bound to the cementing material and thus becomes one integral part of the same without any tendency to burst from the finished product. It's pretty surprising that the finished products are so considerably

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have reduced densities despite the integrating mixing of the defibrated material into the matrix. One would have expected that the fluffy material would - at least to some noticeable extent - be under the pressure of the system collapses.

For the production of the gypsum lightweight wall panels according to the teaching of the present invention, one can use the usual Use methods such as those used in the manufacture of the known wall panels. Furthermore the product can also contain conventional additives such as those described in U.S. Patent 3,314,613 ground plaster accelerator.

One embodiment of the method for producing the lightweight gypsum wall panels with shredded expanded Polystyrene aggregate is shown schematically in FIG. Blueable polystyrene beads with diameters from about 0.794 mm to 6.55 mm (1/32 "- 1/4"), their Density 0.481 to 0.641 g / enP (30 - 40 lbs. Per cubic foot) are stored in a storage container 1 for the raw pearls. As needed, they will go through the feeding device 2 is fed to the expanding device 4 for the pearls, where they come into contact with water vapor which is fed to the expanding device 4 through the line 3. The pearls will inflated to about 6 to 10 times its original diameter due to the action of heat and emerge from the expansion device close to the cover of the same and pass from there through the feed device 5 into the storage container 6. From here will be according to the need by the task

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Direction 7 of the expanding device 8 is supplied, in which the beads are further inflated by the action of additional steam heat to approximately 7 to 12 times their original diameter. Notwithstanding this, the beads from the expanding device 4 can also be fed directly to the storage container 10. When the pearls expand, the organic liquids, such as pentane, which have been enclosed in the pearls during the manufacturing process, escape; this further reduces the density of the polystyrene for this purpose, the storage containers 6 and 10 are preferably mesh storage containers. From here, the expanded pearls pass through the feeding device 9 into the storage container 10, and from there they are fed via the feed device 11 to the fiberizing device or grinder 12 and pass via line 13 into the storage container 14 fine particles are crushed, and the particles are irregular in shape. Approximately 1 % of them are retained on the 4-mesh screen and 96 % of them are retained on the JO-mesh screen (referring to each of the US standard series screens). The expanded polystyrene aggregate fiberized in this way arrives from the storage container 14 through the feed device 15 into the screw conveyor 16, where it is evenly mixed with the other dry components of the gypsum wall panels, with the exception of burnt gypsum. The mixture flows via line 17 to the screw conveyor 18, where it is evenly mixed with plaster of paris. Via line I9

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the mixture reaches into the mixing chamber 21, where it is mixed with water which is supplied through the line 20. The resulting slurry 24, which forms the core of the gypsum wallboard, is applied through the outlet 22 to a moving paper 2.J> , and the combination is passed through the Pormwalzen 25 and 26, where it is applied to the paper 2.J> is spread to a uniform thickness. In this embodiment of the invention, the roller 25 is also intended to apply a paper layer 27 as a cover layer to the wall panel. Conventional means, not shown, can be used to fold the outer edges of the paper 2 ^ on and over the paper sheet 27 so as to form the edges of the panel. According to a modified embodiment, the fiberized, expanded polystyrene aggregate can be fed directly to the screw conveyor from the feeder 15, in which case other drying ingredients such as accelerators, starch and the like can be mixed into the plaster of paris beforehand. According to a further modification, the defibrated aggregate can be mixed with a stream of water and added to the other components in the mixer 21.

FIG. 2 shows a section through a wall panel according to the invention which is provided with the paper linings kO and 41 and has a core which is mainly made of hardened plaster of ^paris; +2, in which the shredded, expanded polystyrene aggregate is dispersed.

The expression "baked gypsum", which is used throughout this description of the invention, is intended to describe the product

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draw, which is commonly used for the manufacture of plasterboard wall panels. This product consists of calcium sulfate which has been calcined to drive off some of the water of crystallization, forming a product which corresponds _{essentially to the formula CaSO ^ .1 / 2H 2 O.}

Becomes a fiberized, expanded polystyrene aggregate incorporated into Portland cement mortar or Portland cement concrete, the finished products essentially have the same desirable properties as found in the gypsum products described above. the Cement products have good strength properties and densities that are considerably lower than they are normally achieved and the frayed aggregate is uniform in the cement matrix dispersed and firmly bound to the finished product. These products can be any other material as they are usually mixed into Portland cement, e.g. dispersants, foaming agents, Asbestos fibers, clay and other aggregates, The frayed, expanded polystyrene aggregate can be used in the Mixture used with any type of portland cement but is best used in types I, II and III.

The lightweight concrete components obtained with these mixtures can be made without the use of vacuum deformation and without the need to subject the concrete mix to autoclave treatment «. In such mixtures, the shredded aggregate replaces

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In fact, some of the mixed-in water does not matter without the mixture reducing it Experienced pourability. The mixture achieves its desired strength using those commonly used in concrete Mixing and hardening procedures. Such lightweight concrete components can be used as prefabricated walls used in industrial buildings. They can also be cast into panels for inclined wall constructions or as Roof panels or partitions are used.

example 1

0.454 kg (1 pound) of a fiberized, expanded polystyrene aggregate having a bulk density of 0.00865 g / cnr (54 pounds per cubic foot), the mesh size of which was so great that 0.8 # was retained on a 4-mesh screen were, 31 * 4 % was retained on an 8-mesh screen, 56.2 % was retained on a 16-mesh screen, 8.3 % was retained on a 30-mesh screen, and 3 * 2 % passed through a 30-mesh screen added to 44.91 kg (99 pounds) of plaster of paris and mixed thoroughly. The mixture was then mixed with water to give a slurry, and the slurry was poured into a mold. The slurry had set in 30 minutes and resulted in a hard product of a shape conforming to the shape.

Example 2

A plasterboard wall panel that is 12.7 mm (1/2 inch) thick and whose width was 1,219 m (4 feet) was made from a mixture of 567 kg (I250 pounds) of plaster of paris, 3 # 63 kg (8 pounds) starch, 14.51 kg (32 pounds) ground plaster of paris

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Accelerator, 0.454 kg (1 pound) of fiberized expanded polystyrene aggregate (96 % of which passed through a 4 mesh screen and was retained on a 30 mesh screen) and 0.91 kg (2 pounds) of lignin. The mixture was mixed until a uniform mixture was obtained. Then water, paper pulp (0.39 g / dm, on dry weight basis, corresponding to 8 lbs. Per thousand square feet) was calculated

-MSF- dry basis) and a foaming agent (0.024 g / dm, calculated on dry weight, corresponding to 0.5 lb / MSP dry basis) are mixed into the mixture to form a uniform slurry of the product. The slurry was then poured onto paper and a liner was placed on top of the topsheet with the edges taped to form a sheet 12.7 mm (1/2 inch) thick and 1.219 m (4 feet) wide. to form after the whole was passed through forming rollers. The weight of the paper layers surrounding the gypsum core was 7.1 J> g / dm (150 Jbs. MSF). The product was passed through a drying oven to remove the excess water to be removed, and the dry weight was 84.7 g / dm ² (1735 lbs. MSF). In one drying method, it was possible to run the plasterboard through the drying oven at a speed of 36.58 m (120 feet) per minute and that represents an increase in speed of 3 * 05 m (10 feet) per minute versus speed which is required in the known technical plasterboard in the same operation without the use of shredded expanded polystyrene aggregate. The boards available on the market require twice as much pulp for their production and consequently require additional amounts of water.

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212994?

Example 3

The procedure steps of Example 2 were repeated using 385.5 kg (850 lbs.) Of stucco, 3.63 kg (8 lbs.) Starch, 13.6 kg (30 lbs.) Of ground gypsum accelerator, 13 * 6 30 lbs. (30 lbs.) of fiberized expanded polystyrene aggregate and 2 lbs. (0.907 kg.) of corn sugar known under the trade name "Cerelose". The prepared from this mixture, 12.7 mm (1/2 inch) thick wall plate weighing 58 g / dm ² (1200 lbs. MSF).

Example 4

0.45 ^ kg (1 pound) of fiberized, expanded polystyrene aggregate was mixed evenly with 44.9 kg (99 lbs.) Portland Type I cement. The mixture was slurried with water and then poured into a mold. After 3 hours the pulp had set and turned into a converted into solid product that had taken the shape of the mold.

Example 5

Defiberized expanded polystyrene aggregate having a bulk density of 0.0078 g / cnr (0.49 pounds per cubic foot) of which 96 % passed through a 4 to 30 mesh screen became 226.8 kg (500 pounds) portland cement type III added in the following amounts: 6.8 kg, 4.54 kg and 3.17 to 5.44 kg (15 * 10 and 7-12 pounds). The hardened concrete products made from these mixtures had densities of 0.432 g / cm ⁵ , 0.641 g / cm ⁵ and 0.801 g / cm ⁵ (27, 40 and pounds per cubic foot). The products had pressure

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Strengths of 3 ^ * 7 kg / cm, 70.3 kg / cm and IO9 kg / cm (550, 1000 and I550 psi).

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Claims (8)

_ ₁₃ . 212994? Claims Substantially uniform, water-setting compositions, characterized in that they consist of (a) plaster of paris or portland cement and (b) shredded or shredded expanded polystyrene aggregate consist, said aggregate making up about 0.01 to about 5 percent by weight of the mass. 2. Composition according to claim 1, characterized in that the component (a) consists of plaster of paris. 3. Composition according to claim 2, characterized in that the aggregate is about 0.05 to about 3 percent by weight of the crowd. H. Gypsum wall panel, characterized in that the core has been produced from a mass according to claim 3. 5. plaster wall panel according to claim 4, characterized in that that the aggregate makes up about 2 to about 3 percent by weight of the wallboard. 6. plaster wall panel according to claim 4, characterized in that the aggregate is about 0.05 to about 0.5 percent by weight of the wall plate. 7. Substantially uniform, water-setting compositions, characterized in that they are made of (a) Portland cement and (b) crushed or ground polystyrene aggregate 109853/1 682 consist, said additive making up about O ₅ oil to about 5 percent by weight of the mass. 8. Composition according to claim 6, characterized in that component (a) consists of portland cement mortar, 9 · mass according to claim 6, characterized in that component (a) consists of portland cement becon. 109853/1682