DD160516A3 - METHOD FOR PRODUCING A HYDROPHOBIC PLASTER FOR PLASTER PANELS - Google Patents

Abstract

In the process of gypsum plasterboard production the gypsum possible small amounts of such hydrophobic substances are added in solid form, which lead while retaining the technological process parameters and low additional material costs to hydrophobic plasterboard while maintaining the usual physical properties u. This can be achieved by adding a Montan wax combination in solid, finely divided form to the binder hemihydrate and / or anhydrite and water and subjecting the resultant mixture to a chemical reaction after setting by thermal treatment in which chemical and physical bonds are formed between the polar groups of the wax and the cations of the binder. By optimally controlling the process, even with the use of small amounts of hydrophobing agents, it is possible to produce gypsum plasterboards having hydrophobic properties that can be used in wet rooms.

Description

223141

Title of the invention

Process for producing a hydrophobic gypsum for plasterboard

! ^ Field of application of the invention

Process-related production of plasterboard for the construction industry with hydrophobic properties, in which, as in the normal building board production, applied gypsum water slurry on a continuous, horizontally running board web

10, which covers the front and edges of the plasterboard. The top carton for the back of the gypsum board is placed on the mass of Gypswasserwasserrei and glued on the protruding side portions of the sub-carton. The gypsum water slurry u. a. Additions

15mischt that give the plasterboard after heating and drying water-repellent properties and these can be exposed to the conventional building panels higher moisture loads.

20Characteristics of the known technical solutions to make building materials, as well as gypsum, water resistant, is an old inlying. In many publications, water repellent substances are added to the gypsum, u. a. also lime. The co-ordinators used in recent years

25ths are mainly silicones, paraffin wax emulsions, ceresins, ozokerites, bitumen, resin emulsions and also water-soluble silicates ··- Apart from the water soluble silicates, their effectiveness in imparting water resistance is mainly due to their ability to mechanically complicate the movement of water. The effect of these additional

Substance depends mainly on the size and distribution of the emulsion beads. Numerous patents describe water-repellent effects for gypsum, which are to be achieved by combined additives, as in 5a. As wax and / or asphalt and corn flour with potassium permanganate; water-insoluble thermoplastic materials containing petroleum and natural asphalt, coal tar and polymers based on vinyl acetate and vinyl chloride; a mixture of alkali metal resin soap, a water-soluble alkaline earth metal salt

10 and fuel oil residue, pine resin with coal tar; a mixture of fuel oil residues and resin; aromatic isocyanates and diisocyanate; Organohydrogenpolysiloxanes; Y / axle - asphalt emulsions; Polyvinyl alcohol additive and metal components and addition of an aqueous emulsion of asphalt / wax in conjunction

15 with calcined gypsum and small amounts of a borate compound. In addition, the adhesion problems cardboard and gypsum play an important role in the processes for impregnating or hydrophobicizing plasterboard. It was found that the majority of the water repellents · a solid

To counteract adhesion or to subsequently cause the detachment of the cardboard from the plaster core due to exposure to moisture, and furthermore adversely affect the quality of the cardboard in addition to the adhesion problems. In addition, with gypsum plasterboard reduced strength values can be determined and the water

Independence decreases with time.

At DE Ur. 1 266 200 is a process for the production of paper-coated, water-repellent plasterboard. A plaster slurry is formed between paper webs and a water-repellant mass, a

30 emulsion of tall oil, a wax-like aliphatic carbon, and a drying oil and / or a fatty acid ester of pentaerythritol. This emulsion is applied to the papers and heated in an oven at a temperature of at least 130 ⁰ C. This surface impregnation

However, there is a disadvantage in the fact that the plaster is damaged by the moisture in the air or the condensation when the paper layer or the seals of the pipes leading through the building board are damaged.

nwR7.1983 * O748öO

Following the procedures DD 125861 and 130133, precast concrete, gypsum, and clay precursors are soaked with liquid paraffin after drying prior to being cooled, to make them watertight. For the same purpose, according to the patent DD 132, a method of melt impregnation is proposed. Paraffin bitumen granules are added to the starting materials, and the finished parts are dried after production. The molten impregnant penetrates into the

, Pores, cools and clogs them up. As practice shows

However, adequate resistance to gypsum is only achieved with additions of about 15% by weight of paraffin. Due to the high material costs, this process is uneconomical. Also in DE OS 2 614 394 reaches u. a. Paraffin for use. In order to guarantee economic use, emulsifying

15ionsen produced and used. The solids content of the 'hydrophobing agent, based on gypsum hemihydrate, is 5% by mass. ^ It will u. a.'Paraffin emulsions, the preparation and composition of which is provided under protection. For the gypsum plasterboard producer is the

20I'Tachteil in the purchase of an emulsifying plant, the storage of at least five source chemicals and the required use of qualified personnel for the grain-placed technological process of metering the components. But if the emulsion is processed by a chemical factory

Pulled up to 65% water are to be transported additionally; In addition, the stability and durability of these emulsions is limited and insulation of the tanks in periods of frost is required

 Furthermore, according to GB-PS 619 281 waterproof products

Obtained with a continuous Yiasserfestigkeit by paraffin waxes or mixtures thereof with carnauba wax in solid form added to the gypsum slurry or subjected as an emulsion to a temperature treatment by the products from room temperature when transferred to the dryer with an all-

35mählichen temperature increase to 166 ⁰ C undergo and then a down to room temperature. Uachteile arise in this dryer guide, since in the melting range of the hydrophobing agent no longer effective

A Π MD 7 4 0 Q 0 * Π Π /.· Q

Residual moisture is present. According to the invention, the most favorable water-resistant results are achieved with additions of 10-14 % paraffin wax. Practice has shown that the use of carnauba wax alone or carnauba wax in mixtures with paraffin requires high levels of use, the carnauba wax additive serving to regulate the melting point. By according to the invention GB'PS 619 281 high amounts of water repellents result in comparison to the usual plasterboard and other gypsum elements

LOTTachteile in the structural-physical characteristics. The fields of application of these water-resistant gypsum products are limited by a very unfavorable fire behavior and reduced dry bending fracture strengths. Penetration of the cardboard with hydrophobicizing agents causes disadvantages due to such

15 or no adhesion of paint and coating systems. In addition, the outer image is reduced by staining 'on the cardboard surface.

Montan wax is industrially produced in a large scale around since the turn of the century and ^e, inter alia as a means for encrypting

201 hydrophobic properties used in various areas. However, it has not found application as a component of granulated water repellents for building materials.

Object of the invention

The object of the invention is to economically produce, with the least possible use of hydrophobizing additives, a continuous hydrophobic gypsum plaster board which has the same positive structural properties as normal gypsum plasterboards and moreover still in rooms with a relative air quality.

30 humidity> 75 % can be used.

- Explanation of the essence of the invention

The invention has for its object to provide a method for hydrophobizing gypsum, in particular for the production of plasterboard, the adhesion gypsum / Ka'rton and a resistance 'to temporarily high moisture contents of the surrounding air while maintaining the structural properties of normal plasterboard safeguards.

According to the invention the object is achieved by a method "in which montan wax in combination with solid hydrocarbons, referred to in the future as Montanwachskombination, as a water repellent powder and / or granules with 5dem gypsum added to the water and mixed to form a homogeneous slurry or the water repellent gypsum water The subsequent setting process and the hate adhesion gypsum / cardboard remain uninfluenced, side by side dihydrate, montan wax combination and water are present.

10den. In the subsequent thermal treatment, the temperature in the dryer is controlled so that at material temperatures up to about 60 ⁰ C, the plasterboard does not dry completely to form cavities. The plates then have to be briefly heated to about 85 ^° C., so that the mono-

15tanwach combination melts, supported by the vapor pressure of the residual water, penetrates into the existing cavities and enters a chemical reaction, which lead to the formation of bonds between the montan wax combination and binder * These reactions are characterized by partial Versei-

By reacting the carboxyl groups of the montan wax combination with occurring cations of the binder under the conditions of the short heating phase, it has been found that this reaction is bound to a minimum acid number of 5, preferably 10 to 35. The water-repellent treatment

25ergibt by the shielding of the Dihydratgerüstes means of Montanwachskombination, whereby the capillary suction force typical for gypsum is greatly reduced or for the most part prevented. Combinations of montan wax mit.festen hydrocarbons, whose

The solidification point> 50 ⁰ G is in question. Taking into account the production process of plasterboard according to the invention was found that the Montanwachskombination as a hydrophobing agent in the form of a fine granules with a particle size range of 0.063 - 0.8 mm, most favorable from 0.1 to

350.5 mm, is to be used. Special water repellency effects are achieved when using combinations of montan wax with at least 40 mass-SS solid hydrocarbons. Surprisingly, it has been found that in a combination of

90-25% by mass of montan wax, characterized by an acid number of 28-32 and a content of acetone-soluble resin materials of 10-14%, with 10-75% by mass of solid hydrocarbons water repellents can be prepared with Sdenen the amounts compared to the proportions of hydrophobizing agents customary in practice and reported in the literature in the production of plasterboard can be reduced to a hitherto not customary degree of <4 * mass% , since the melt viscosity is obtained by this combination

10des hydrophobing agent according to the invention in a process necessary for the range of 20 - 35 is brought cP and a necessary for the process of volume expansion in Schmelzber calibration of montan wax combination of 6.5% - 11.5% is provided. At the same time, the acid number of the monomers

15tanwachskombination adjusted to values of 12-18, which are prerequisite for the indicated saponification reactions. The Wasseraufnähme the corresponding plasterboard is significantly reduced, the other physical properties are not adversely affected. Through the

Excess binding of the Liontan wax combination in the hardened gypsum avoids expulsion of the admixture, achieves an even distribution and therefore achieves an unexpected quality with low quantities. Lifting these favorable values, the hydrophobicizing agent offers

25th at the same time a better edge resistance against short-term overheating in the dryer. Further improvements of the strengths, water resistance u. a. Properties,

, are possible under the abovementioned conditions if the entitlement to use of the gypsum binder used to achieve the

30Consulting consistency lowered and thus a denser structure is achieved. This is z. B. possible by the use of * C -Halbhydr.at- or anhydrite-II binder or the addition of liquefiers to normal hemihydrate gypsum. However, positive results were also achieved if the gypsum slurry was

35 or pore-forming substances added and the bulk density of the finished plate was reduced.

Although the flexural strengths are somewhat lower than the normal structural panel, the hydrophobic character of the

Asked lightweight panels quite complies with the requirements for installation in damp rooms.

Exemplary embodiments FIG. 1

3 % by mass of a combination of montan wax and solid hydrocarbons having an acid number of 12-18 and a grain composition of

<0.2 mm 19.8 % 0.2 mm to 0.315 mm 51.6 %

0.315 mm to 0.5 mm 27.2 % 0.5 mm to 8.8 mm 1.0%

> 0.8 mm 0.4 %

are mixed with a mixture of hemihydrate and / or anhydrite with 15Wasser. The gypsum plasterboard produced had a water absorption on average after 2 h = 1.48%, after 24 h = 4.1 %, after 96 h = 6.5 % and after 120 h = 6.8 %.

Example 2

Mass% of a combination of montan wax and solid hydrocarbons having an acid number of 12-18 and a grain composition of

<0.2 mm 1 % 0.2 mm to 0.315 mm 7%

0.315 mm to 0.63 mm 65 % 0.63 mm to 0.8 mm 25 %

> 0.8 mm 2%

are mixed with a mixture of hemihydrate and / or anhydrite with water. According to the prescribed test after 2 h of water storage, the test specimens of the gypsum plasterboard absorbed between 3.7% and 4.1 % of water due to fluctuations in the hydrophobizing agent in the gypsum plasterboard.

1983 * 074 800

Claims (3)

Erfindungsanspruoh 1. Process for the preparation of hydrophobic gypsum plasterboard. a mixture of hemihydrate and / or anhydrite, characterized in that the mixture contains less than 4% by mass of a combination of montan wax with solid hydrocarbons having an acid number of 5, preferably 10-35, a melting point of -75-88 ⁰ G, has a volume expansion of 6.5 - 11.5 % ' and a melt viscosity of 20 - 35 cP, in a solid, 1Ofeinverteilter form is mixed and the plates following a thermal treatment to 60 ⁰ G material temperature with a subsequent brief heating to 85 ⁰ C. be subjected. 152. The method according to item 1, characterized in that the combination of 90 -. 25 % montan wax and 10 - 75 % solid hydrocarbons. 3. The method according to item 1, characterized in that the Kom-20bination of montan wax and solid hydrocarbons in granulated onon in a particle size range of 0.063 to 0.8 mm, preferably 0.1 to 0.5 mm is used. 1983 * 074 800