Abstract: A method for producing a modified smectite or smectite-containing substance including treating a non-activated smectite or substance with a water soluble activating agent and polymer in a two stage process, the first stage including adding 0-3.0% of the activating agent and 0.05-1.0% of the polymer, by weight, and in a second stage adding 0-5.0% of the activating agent 0.3-5% of the polymer, by weight, to the mixture of the first stage, wherein at least a part of the polymer is added as a dry solid and the water in the first stage is at least 20% by weight and at most 50% by weight in the second stage.

Abstract: The present invention relates to a method for producing a modified smectite or smectite-containing substance capable of forming gels which are not longer thixotropic, have a stable cross-linked structure and adhesive characteristic and are capable of taking up and releasing water in a reversible manner by treating a non-activated smectite or smectite-containing substance with a water soluble activating agent and with a water soluble polymer capable of reacting with said smectite, wherein 0-6% by weight, calculated on the weight of the smectite, of the water soluble activating agent and 0.

Abstract: The invention relates to a clay-containing mixture or blend capable of forming a moisture resistant gel, which comprises a powdered or ground smectite and/or a smectite-containing natural rock and at least 0.8–10% by weight, calculated for the smectite content, of an at least partially water-soluble and/or water swellable polymer and optionally at least 0.5% by weight of a solid activating agent. Such a mixture may also additionally comprise as a diluting agent more than 0.5% by weight of one or more solid inert filler(s); this diluted version is termed in the specification as a blend.

Abstract: A clay-containing mixture of dry solids to be used in forming a moisture-resistant gel, and a method for directly forming a moisture-resistant gel on a surface to be treated, using such a mixture. The present invention furthermore relates to the use of such a mixture.