HU185376B - Self-spreading, floor surface-evening dry mortar of decreased shrink as well as method for producing same - Google Patents

Abstract

The slab felt filler dry mortar according to the invention is characterized in that sand with a specific surface area of 1 / 12-1 / 18-ad calculated on the surface of the cement used, with a cement content of up to 20% by weight of aluminium clinker, 50% to 70% by weight of cement as a modifying binder. in itself 1.0-1.5 mm / m of hydration swelling - gypsum and optionally at least one resin. In the process of the invention, the components listed above are mixed and then homogenized. The advantage of the self-leveling slab-leveling dry mortar according to the invention is that the mortar made therefrom is less shrinkable and consequently does not crack compared to the previously known commercial products, furthermore a thicker balancing mortar layer can be made, which solves the inevitable problems of mass production. -1-

Description

The present invention relates to a dry shrinkable self-leveling floor leveling mortar containing sand, cement and resin, and to a process for its preparation.

When laying glued and tensioned floor coverings, a firm and smooth substrate is required, as soft floors (carpet, PVC flooring, linoleum, etc.) are redrawn on uneven floors. Therefore, the surface irregularities (porosity, cracks, pebble holes, level differences) of the monolithic and prefabricated load-bearing ceiling structures must be compensated by a few layers of mortar, if any, tens of millimeters thick, the material of which is subject to the following main requirements:

1. The components of the mortar, mixed with water, shall not be separated during transport and application or until solidification.

2. Productive application requires a self-leveling feature, so the mortar poured onto the substrate must reach the horizontal without manual smoothing.

3. The applied layer should cure evenly and quickly, despite varying thicknesses.

4. The screed must adhere perfectly to its substrate, and must withstand its hard mechanical stress without damage due to its hardness or strength.

5. Shrinkage cracking or layering shall not occur on the screed within the required thickness limits.

6. The solidified surface must be smooth, free from creases and larger air pores, and should not be damaged by conventional coating adhesives.

Commercially available smoothing powder products generally do not fully meet the above requirements, and users are forced to make significant technical or economic compromises.

French Patent No. 1,335,833 and Japanese Unpublished Patent Publication No. 76,145,525 disclose a cement mortar composition comprising gypsum in addition to cement binder. Although such compositions have less shrinkage, their rheological properties and adhesion to the slab are not satisfactory.

The object of the present invention is to provide a product which can be manufactured simply and economically and which fully meets the requirements of the application. A further objective is to increase the low layer thickness (up to tens of mm) specified for known products (up to tens of mm) and to apply the leveling mortar in a single operation without the risk of shrinkage cracking.

It has been found that the rheological properties of cementitious mortar are largely influenced by the specific surface area of the solid composite. It has been found that optimum self-leveling is achieved when the specific surface area of the fine sand is 150 to 200 cm ² lg, which is 12-18% of the specific surface area of the cement binder. The rheological and mechanical properties are favorably modified by 0.5 to 2% by weight of water soluble melamine-formaldehyde resin in powder form, 0.8 to 4.0% by weight of filter copolymer and 0.5 to 8% by weight of lactam monomer or lactam monomer and lactam oligo. dosing of a mixture of dar.

The tendency of screeds to crack and separate from the substrate is primarily due to the shrinkage of the cement during hydration, the average value of which is 0.5 mm / m for each cement type. It has been found that this bloating can be compensated by the addition of a sufficient amount of calcium sulfate and lactam monomer and oligomer containing approximately 1 (2 crystalline water). The hydrated swelling of the partially dehydrated calcium sulfate alone is 1.0-1.5 mm / nr. A. In the dry mortar of the present invention, only those types of cement binder which contain up to 20% by weight of aluminous clinker may be used, excluding the formation of ettringite which causes a harmful increase in volume of £ 1. To ensure proper adhesion of the mortar layer to the solidified substrate, the dry mix

It also contains a styrene copolymer with an acid number of 8-12.

By using the lactam monomer or the mixture of lactam monomer and 2Cf oligomer, as mentioned above, the shrinkage tendency of the mortar can be further reduced and the adhesion of the mortar to the substrate can be increased. Preferably the lactam is caprolactam, but lauryl lactam can also be added. In a preferred embodiment, a lactam monomer is used which also contains 5-20% by weight of oligomer. The number of repeating units in the oligomer is 2-10. Thus, not only the pure lactam monomer can be used in the composition of the invention, but also a lactam production cavity which is not applicable in the lactam polymerization process. This also contains the lactam oligomer.

The present invention relates to a reduced shrinkage self-leveling slab leveling dry mortar which:

15-200 cm ² / g of sand with a specific surface area, cement containing up to 20% by weight of alumina clinker mineral and 10-35% by weight of gypsum with a hydration swelling of 1.5, 5 mm / m and 0.5-2% by weight of solid melamine-formaldehyde resin, 0.8-4% by weight of a styrene copolymer and 0.5-8% by weight of a lactam monomer, preferably caprolactam or a mixture of lactam monomer and lactam oligomer. The composition of the invention is prepared by mixing cement and sand and solid melamine formaldehyde resin, and then adding the styrene copolymer and the lactam monomer or lactam monomer-lactam oligomer mixture and mixing until a homogeneous mixture is obtained. we do not get.

The composition and process of the present invention are illustrated by the following embodiments;

/. example

Sand with a specific surface area of 176 cm ² lg and an average grain size of 0.16 mm 42.0 sr.

partially dehydrated calcium sulfate (burnt gypsum) 20.0 sr.

2800 cm ² / g specific surface cement '33.5 sr.

8 to 12 styrene copolymer 3.2 sr.

water-soluble melamine formaldehyde resin, solid 0.8 sr. caprolactam 0.5 sr.

100.0 sr.

185,376

From the weighed raw materials, the sand, melamine formaldehyde resin, and cement must be homogenized on a collar passage or other powder mix homogenizer for 40 minutes, then the styrene copolymer and caprolactam are added and stirring is continued for another 10 minutes. The product is packed in welded polyethylene bags for moisture protection during storage.

Processing

The bagged mortar is mixed homogeneously with free-flowing water or a 2 to 4-fold amount of tap water at the place of use with a forced mixer. The substrate to be leveled is delivered by hand (mortar) or via a mortar pump via pipeline. Pour and distribute the paste within 30 minutes of mixing.

On-site panel building experiments have shown that mortar cures within 12 to 12 hours at a temperature of 15 to 20 ° C, and is suitable for bonding floor coverings after 24 hours, with a Schmidt hammer strength equivalent to that of on-site nodal concreting.

In further experiments, due to the inhomogeneity of the subfloor, the thickness of the slab leveling mortar layer of the present invention was increased and it was found that shrinkage cracking does not occur at a thickness of more than ten mm, unlike other commercially available products.

Example 2

190 cm ² / g specific surface area sand 0.13 mm average grain size 36.0 sr.

calcium sulfate (stucco plaster) 27.0 sr.

2900 cm ² / g specific surface cement 30.0 sr.

styrene copolymer (8-12 acid number) 1.0 sr.

solid, water-soluble melamine-formaldehyde resin 1.0 sr. caprolactam monomer (containing 10% oligomer content, repeating units: 5) 5.0 sr.

100.0 sr.

The composition is prepared and used as described in Example 1.

3. (Comparative example)

In each case, the procedure was as in Example 1, but 20 sr. instead of gypsum, 5.0 sr is used and the composition does not contain the addition of myelamene resin, styrene copolymer and caprolactam. They are filled in half with sand or cement.

With this composition, a slab leveling layer of ten mm thickness was prepared as described in Example 1. Cracks appear on the hardened layer and the screed is separated from the substrate in several places.

Claims (7)

1. Reduced shrinkage self-leveling dry mortar containing sand, cement, gypsum and synthetic resin characterized in that, with a specific surface area of 150 to 200 cm ² / g, as binder: not more than 20% by weight of cement with an alumina clinker content of 1035% by weight 1 Gypsum with hydration swelling 0-1.5 mm / m, 0.5-2% by weight of solid melamine-formaldehyde resin, 0.8-A% by weight of styrene copolymer and 0.5-8% by weight of lactam monomer, preferably caprolactam monomer, and lactam monomer, preferably caprolactam, and Dry mortar according to claim 1, characterized in that it contains partially dehydrated gypsum. (Priority: 04.08.1980) 3. The dry mortar according to claim 1, characterized in that it contains plaster. (Priority: 08.04.1980) 4. The dry mortar according to claim 1, characterized in that it comprises a solid water-soluble melamine-formaldehyde resin. (Priority: 08.04.1980) The dry mortar according to claim 1, characterized in that it comprises a styrene copolymer having an acid number of from 8 to 12. (Priority: 08.04.1980) 5 to 20% by weight of a mixture of lactam oligomers. (Priority: March 14, 1984) 6. A process for the preparation of a reduced shrinkage self-leveling slab leveling mortar comprising sand, cement and resin, leaving a specific surface area of 150-200 g / cm ² sand, cement containing up to 20% by weight of aluminate clinker, 10-35 1.0% to 1.5% w / w of gypsum with hydration swelling and 0.5 to 2% by weight of solid melanin-formaldehyde resin are dry mixed, then 0.8 to 4% by weight of styrene copolymer and 0.5 to 8% by weight are added. a mixture of lactam monomer%, preferably caprolactam, or a mixture of lactam monomer, preferably caprolactam, and 5-20% by weight of lactam, and the composition is blended until complete homogeneity is achieved. (Priority: March 14, 1984) 7. A process according to claim 6, wherein said mixture of sand, cement, gypsum and melamine-formaldehyde resin is mixed with said styrene copolymer having an acid number of from 8 to 12% by weight.