Thermally insulating aerogel based rendering materials

Abstract

In order to produce a high performance thermally insulating rendering, a dry blend is provided that consists essentially of: 60 to 90 Vol.-% of a hydrophobized granular silica aerogel; 0.5 to 30 Vol.-% of a purely mineral binder; 0.2 to 20 Vol.-% of an open-porous water-insoluble or slowly water soluble additive having an accessible pore volume from 10 to 90 Vol.-%; up to 5 Vol.-% reinforcing fibers; andup to 5 Vol.-% of processing additives. After mixing the dry blend with water, the slurry thus formed can be applied to a surface or shaped to a self-supporting body using an overpressure without adversely affecting the thermal insulation properties.

Claims

1. A dry blend for producing a thermally insulating rendering, consisting essentially of: 60 to 90 Vol.-% of a hydrophobized granular silica aerogel; 0.5 to 30 Vol.-% of a purely mineral binder; 0.2 to 20 Vol.-% of an open-porous water-insoluble or slowly water soluble additive having an accessible pore volume from 10 to 90 Vol.-%; up to 5 Vol.-% reinforcing fibers; up to 5 Vol.-% of processing additive; and, wherein said open-porous additive is pumice.

2. A dry blend for producing a thermally insulating rendering, consisting essentially of: 60 to 90 Vol.-% of a hydrophobized granular silica aerogel; 0.5 to 30 Vol.-% of a purely mineral binder; 0.2 to 20 Vol.-% of an open-porous water-insoluble or slowly water soluble additive having an accessible pore volume from 10 to 90 Vol.-%; up to 5 Vol.-% reinforcing fibers; up to 5 Vol.-% of processing additive; wherein said open-porous additive has a particle size from 0.04 to 4 mm; and, wherein said open-porous additive is pumice.

3. A dry blend for producing a thermally insulating rendering, consisting essentially of: 60 to 90 Vol.-% of a hydrophobized granular silica aerogel; 0.5 to 30 Vol.-% of a purely mineral binder; 0.2 to 20 Vol.-% of an open-porous water-insoluble or slowly water soluble additive having an accessible pore volume from 10 to 90 Vol.-%; up to 5 Vol.-% reinforcing fibers; up to 5 Vol.-% of processing additive; wherein said open-porous additive has an accessible pore volume from 45 to 55 Vol.-%; and, wherein said open-porous additive is pumice.

4. The dry blend according to claim 1, wherein said open-porous additive has a relative water absorption capacity by weight ranging from 1.1 to 2.5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above mentioned and other features and objects of this invention and the manner of achieving them will become more apparent and this invention itself will be better understood by reference to the following description of various embodiments of this invention taken in conjunction with the accompanying drawing, wherein is shown:

(2) FIG. 1: Thermal conductivity of different rendering mixtures as a function of pressure (relative to atmospheric pressure), wherein: Mixture A is a cement based mixture without open-porous additive, Mixture B is a mixture without cement binder and without open-porous additive; and Mixture C is the same as mixture B but with the inclusion of an open-porous additive.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Examples

(3) The various components such as a hydrophobized granular silica aerogel, a mineral binder, an open-porous additive and any processing additives are blended manually or by means of industrial mixing equipment in-factory, and the dry blend thus obtained is packed into sacks for delivery. On the construction site, the dry blend is mixed with a predetermined amount of water and processed by means of commercially available mixer for a predetermined time to form a homogeneous mass. After a predetermined mixing pause, the mass is mixed further and can subsequently be applied by conventional plastering equipment to form a single layer with a thickness of about 20 to 80 mm.

(4) Alternatively, the above formed dry blend is mixed on the construction site with a predetermined amount of water and applied as a layer of 20 to 80 mm by means of a commercially available spray plastering machine and subsequently evened off by conventional tools.

(5) A thermally insulating base with an aerogel blend as described above can be applied with the following steps: 1) apply pre-spray preparatory mortar; 2) apply aerogel based thermally insulating rendering layer; 3) apply reinforcing layer; 4) apply final rendering and paint finish

(6) A useful dry blend for producing a thermally insulating rendering comprises: hydrophobized granular silica aerogel (84.5 Vol-%) mineral binder: white cement (6 Vol-%) and hydrated lime (1.5 Vol-%) pumice as open porous additive (2 Vol-%) polyethylene fibers (1 Vol-%) organosilane hydrophobizing agent (1.25 Vol-%) processing additives: citric acid and dispersing agents (3.75 Vol-%)