GB2102785A

GB2102785A - Flooring Plaster

Info

Publication number: GB2102785A
Application number: GB08220415A
Authority: GB
Inventors: Dieter Altmann; Rudi Bretnuetz; Volker Roeder; Walter Dietze
Original assignee: Leuna Werke GmbH
Current assignee: Leuna Werke GmbH
Priority date: 1981-07-30
Filing date: 1982-07-14
Publication date: 1983-02-09
Also published as: BE893978A; IT1210691B; DE3227563C2; CS246572B1; AT381298B; GB2102785B; NL8202825A; ATA289482A; DD209355A3; IT8248808A0; DE3227563A1; CH653659A5

Abstract

A free-flowing self-levelling floor plaster for dwellings, community buildings and light industry factories is produced by admixture of potassium sulphate and zinc sulphate as is known per se with 0.2 to 2.0% by mass of sodium sulphate and 0.15 to 6.0% by mass of a modified solid melamine resin which are all added in one and the same grinding and mixing process and at a temperature of below 333 DEG K.

Description

SPECIFICATION Process for the production of a free-flowing selflevelling floor plaster This invention relates to a process for the production of anhydride bonding agents from which, by the addition of water and further additives, free-flowing self-levelling floor plasters orscreeds can be produced for dwellings, community buildings and light industry factories, as well as small or large constructional components.

The production of free-flowing self-levelling floor plasters from natural and synthetic anhydride with the addition of activators, plasticizers and water is already known (DDR patent 130781). The fluid an hydride bonding agent is a 3-component product consisting of a basic constituent (anhydrite with activator), a further activator (sodium hydrogen sulphate) and a plasticizer.

This system suffers from the drawback that the added activator has to be dissolved on site and added in a certain quantity to the water. This leaves considerable latitude for error. The dissolution equilibrium is also greatly dependent on the temperature and time, leading to fluctuations in the concentration. In addition, sodium hydrogen sulphate is costly and not easily obtainable.

A further known system is the production of a 2-component product with the use of a specially selected and pre-treated anhydrite (DDR patent 223012).

This again involves the disadvantage that the fluid plasticizer has to be separately proportioned on the building site.

In a further known process the additional activator compound is dispensed with because the plasticizer, in the production process, requires the addition of certain quantities of free acid, preferably sulphuric acid (DDR patent 132425). Besides the additional dosing ofthe plasticizerthis process entails serious disadvantages where the safety of personnel is concerned, particularly in view of the danger from corrosive substances involved. The acid may also be expected to react with limestone present in natural anhydriteform and in the sand. This causes expansion effects and detracts from the surface quality.

The production of a single-constitutent product from synthetic anhydrite, with the use of alkyl phenol as a strengtrhening additive, is likewise known (DE patent 1,170,853).

This suffers from the drawback that no selflevelling effect is obtained.

An object of this invention is to reduce the number of components used in an anhydrite bonding agent for the production of a free-flowing self-levelling floor plaster and to find, for the production of a single-constituent product with a natural anhydrite base, with the addition of activator salts and plasticizers, an activator salt and a plasticizer with which it would be possible, through a grinding and mixing process, to produce an anhydrite bonding agent for which the only further operation required on the building site would be that of mixing it with water.

According to this invention there is provided a process for the production of a free-flowing selflevelling floor plaster with a natural anhydrite base to which an activator salt and plasticizer are added, in which process potassium sulphate and sinc sulphate known per se are ground and mixed with 0.2 to 2.0% by mass of sodium sulphate and 0.15 to 6.0% by mass of a modified solid melamine resin all in the same grinding and mixing process and at a temperature of below333 K. The use of a solid plasticizer was hitherto not usual as all plasticizers added on building sites having been liquid.The solid plasticizer suffers from the drawback of having to be dissolved in water before the production of the mortar, this being a very complicated process and the correct dosage involved in the observance of the right proportions for the constituents is a problem. Due to the admixture of the solid plasticizer in accordance with the invention the individual constituents are evenly distributed in the anhydrite, so that the dissolution characteristics of the activator salts and the plasticizer are distinctly improved and extremely short mixing times obtained without sacrificing any of the required parametersforthe building material or detracting from the self-levelling effect. Sodium sulphate is known as an activator salt which is difficultto dissolve.It therefore was surprising that in the proposed combination of potassium sulphate, zinc sulphate, sodium sulphate and plasticizer it was possible to use sodium sulphate.

It has proved advantageous for 0.5 to 2.0% by mass of potassium sulphate, 0.2 to 2.0% by mass of zinc sulphate and 0.2 to 0.7% by mass of sodium sulphate, as an activator component, to be added by grinding.

The plasticizer is a very expensive product which has to be used in the smallest possible quantities. It has been found that quantities of between 0.15 and 2.0% by mass are sufficient, unless special demands are made on the degree of spreading.

A sand extending operation up to 200% by mass can be adopted in order to render the method more economical without detracting from the quality obtained in the production and processing of the substance and in the application of the fluid anhyd rite mortar. Where a particularly strong fluid anhyd rite plaster is required the sand extending is prefer ably omitted.

The floor plaster can be produced by the free-fall mixing, automatic mixing or continuous high-power mixing process.

The invention is further described and illustrated by means ofthefollowing examples: Example 1 The following were ground together in a tubular ball mill: 96.6% by mass of anhydrite 1.0% by mass of plasticizer 1.2% by mass of potassiumsulphate, 0.7% by mass of zinc sulphate, 0.5% by mass of sodium sulphate.

The temperature resulting from work loss in the grinding process was kept at 327"K by regulating the quantity of the flow. The grinding was effected con tinuously in the quantitative flow of the individual constituents. The fluid anhydrite bonding agent pro duced was placed in product bunkers and despatched in bags or loose in special containers.

On the building site the fluid anhydrite bonding agent was processed for 15 with 25% by mass of mixing water in a continuous high-power mixer to form a mortar capable of being pumped. The mortar was placed in a storage tank and pumped with a mortar pump to the site where it was to be used, where it levelled itself. The floor in question was usable after 10 hours.

Example 2 A fluid anhydrite bonding agent produced in accordance with Example 1 was mixed in a free-fall mixer on the building site with 29% by mass of mix ing water and 100% by mass of sand of a grain size of 0 to 2 mm, thus forming mortar. The finished mortar was capable of being pumped and levelled itself on the site where used. After 15 hours it was possible to walk on the floor.

Example 3 A fluid anhydrite bonding agent produced in accordance with Example 1 was mixed in an automatic mixer on the building site with 200% by mass of sand of a grain size of 0 to 2 mm and 34% by mass of mixing water, thus forming mortar. The mortar was capable of being pumped and was self-levelling.

The floor could be used after 20 hours. The resistance values after 28 days were found to be as follows: Bending Compressive Extender Strength Strength Example {o/OJ (MPa) (MPs) 1 0 9.6 53.5 2 100 6.9 32.2 3 200 6.0 26.5

Claims

1. Process for the production of a free-flowing self-levelling floor plaster with a natural anhydrite base to which an activator salt and plasticizer are added, in which process potassium sulphate and zinc sulphate known per se are ground and mixed with 0.2 to 2.0% by mass of sodium sulphate and 0.15 to 6.0% by mass of a modified solid melamine resin all in the same grinding and mixing process and at a temperature of below3330K.

2. Process in accordance with Claim 1, wherein the activator constituent consists of 0.15 to 2.0% by mass of potassium sulphate, 0.2 to 2.0% by mass of zinc sulphate and 0.2 to 0.7% by mass of sodium sulphate.

3. Process in accordance with Claim 1 or 2, wherein 0.15% to 2.0% by mass of melamine resin is ground into the mixture.

4. Process in accordance with any one of Claims 1 to 3, wherein a sand extension of 0 to 200% by mass in relation to the fluid anhydrite bonding agent is carried out.

5. Process in accordance with any one of Claims 1 to 4, wherein the production of the floor plaster is effected by a free-fall mixing, automatic mixing or continuous high-power mixing process.

6. Processforthe production of a floor plaster as described herein and exemplified.

7. A mix for making-up to a floor plaster produced by the process of any preceding claim.