GENIOSIL® XM - Wacker Chemie AG


New Dimensions for Adhesives and Sealants

The novel silane-modified polymers (SMPs) GENIOSIL® XM 20 and GENIOSIL® XM 25 allow a new formulation strategy for the production of adhesives and sealants. Both grades enhance performance properties without disrupting the existing characertistics of an SMP formulation. Moreover, when incorporated into adhesive and sealant formulations, conventional plasticizers need not be used.

The monofunctional polymers GENIOSIL® XM 20 and GENIOSIL® XM 25 are ideal for the formulation of soft yet highly elastic adhesives and sealants. The resultant adhesive or sealant exhibits virtually universal, outstanding adhesion especially to many difficult, sometimes non-polar, substrates – in particular low-energy surfaces such as PVC, PS or EPDM.

New Player for the Successful SMP Team

As the adhesive and sealant world looks to displace toxic yet high-performance solutions, SMPs have increasingly found their position as the most viable alternative. The novel GENIOSIL® XM range further complements the silane-modified-polymer portfolio under the GENIOSIL® brand.

GENIOSIL® XM 20 is an alpha-silane-terminated polymer and especially targets adhesive applications. Used as a co-binder – in combination with one of the conventional silane-modified polymers (GENIOSIL® STP-E range) – formulations, based on this polymer will give outstanding adhesion to a variety of difficult substrates. Organic plasticizers (phthalates, polyethers and trimellitates) have the tendency to migrate to the surface from within an adhesive and will disrupt the adhesion properties. By replacing the organic plasticizer in an adhesive formulation with GENIOSIL® XM 20, this can be overcome. Typical application areas include flooring and many universal adhesive solutions, where flexibility and strength are sought.

Adhesion Profile Values of GENIOSIL® XM 20 Versus Conventional Plasticizers
Polyether Trimellitate GENIOSIL® XM 20
Storage Conditions Dry Wet Dry Wet Dry Wet
PMMA - - + + + +
PMMA Filled - - + + + +
ABS - - - - - -
PVC - Ø - - + +
PC + - + Ø Ø +
PS - - - - + +
PVC Körnadur ES White - - - - + +
PVC Simona CAW Dark Grey - - - - + +
PVC Rigid Transparent - - - - + +
PVC Flexible Transparent - - - - + -

The table gives values for a formulation based on conventional plasticizers versus GENIOSIL® XM 20, where adhesion was measured under dry and wet conditions: "-" indicates complete adhesion failure, "Ø" indicates partial adhesion failure, and "+" indicates no adhesion failure.

GENIOSIL® XM 25 is a gamma-silane-terminated polymer and particularly targets sealant applications, especially where low-modulus products with high recovery are desirable. Used as a co-binder – in combination with one of the conventional silane-modified polymers (GENIOSIL® STP-E range) – GENIOSIL® XM 25 will yield properties that conform to building specification DIN EN ISO 11600-25LM. Potential application areas include industrially pre-fabricated concrete panels, and connection joints between window frames and walls, where movement capability is a must.

The Impact of Using GENIOSIL® XM 25 in a Low-Modulus Sn-Free Sealant Formulation
Property/Characteristic Value
SOT [min] 30
Shore A 25
Tensile Strength [N/mm2] 1.5
Elongation % 900
Recovery: A: >60%, 0.36 N/mm2
B: >80%, 0.36 N/mm2