moisture curable composition

Abstract

The present invention discloses a two-part moisture-curing organosiloxane composition that is useful as a sealant in insulation systems in building facades and the like and exhibits low thermal conductivity Rate. The two-part moisture-curable composition has part A and part B, wherein part A includes any of the following: 1) a silicone polymer (I) having at least two terminal hydroxyl or hydrolyzable groups, the siloxane polymer (I) has a viscosity at 25°C of 20,000 mPa.s to 40,000 mPa.s; or 2) a mixture of polymer (i) and polymer (ii), wherein polymer (i) is a siloxane polymer having at least two terminal hydroxyl or hydrolyzable groups and a viscosity at 25°C ≥ 25,000 mPa.s, and polymer (ii), having at least two Silicone polymers with terminal hydroxyl groups or hydrolyzable groups and a viscosity at 25°C between 1,000 mPa.s and 20,000 mPa.s, together with reinforcing fillers and low density fillers, wherein the total filler content is between the total formulations between 30% and 45% by volume of ; and Part B includes a moisture curative formulation comprising a suitable amount of a tin-based catalyst and one or more crosslinking agents. The thermal conductivity of the composition of Part A and / or Part A+Part B after mixing is ≤ 0.20 W / mK.

Description

technical field [0001] This article concerns the development of a moisture-curing organosiloxane composition that can be used as a sealant in "high performance" insulation systems in building facades and the like and that exhibits low thermal conductivity. Background technique [0002] Condensation-curable organosiloxane compositions that cure to elastomeric solids are well known. Typically, such compositions are obtained by combining a polydiorganosiloxane having reactive end groups such as hydroxyl groups or hydrolysable groups with, for example, the polydiorganosiloxane in the presence of a suitable catalyst. It is obtained by mixing reactive silane crosslinking agents such as acetoxysilane, oximesilane, aminosilane or alkoxysilane. The resulting composition is curable when exposed to atmospheric moisture at room temperature and is useful as a structural sealant / adhesive in "high performance" insulation systems in building facades and the like. [0003] An important app...

AI Technical Summary

Problems solved by technology

However, although these have been shown to reduce the thermal conductivity of the sealant, their incorporation resulted in a significant increase in the viscosity of the sealant composition prior to curing, which provided the user with insight into how to apply the sealant to / in the ICU. main problem

Typically a sealant gun or other suitable dispensing device is used, but given the increased viscosity due to the introduction of hollow mineral and / or organic microspheres, the speed and efficiency of application of this sealant can be rapidly reduced

[0010] Therefore, while it is necessary to minimize the thermal conductivity of the edge seal, the thermal conductivity of its secondary sealant becomes increasingly important, it is equally important to preserve the other physical properties of the secondary sealant in order to avoid damage to said other physical properties. Reduces other potentially detrimental effects on the aspect while reducing the thermal conductivity of the secondary encapsulant

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