However , not all of them are believed to be entirely harmless to health . The oxime silicones based on methyl ethyl ketoxime ( MEKO ) are considered to be carcinogenic . But now , with Pattex FUSIONXLT , Henkel has launched an oxime-free technology offering impressive user safety and an all-in-one solution that covers virtually every application , whether interior or exterior .

The silicone sealant product group can be divided into three systems : acetate silicones are characterised by their acidic crosslinking process , which means they release acetic acid upon curing and therefore give off a vinegary smell . Their strengths lie primarily in sanitary and kitchen applications .

However , they are unsuitable for some substrates due to their tendency to react with certain materials such as metal or concrete . Another sort , alkoxy systems , undergo neutral crosslinking and are extensively odourless . They are suitable for many substrates but cure relatively slowly , which can lead to sealant contamination .

Neutrally crosslinking oxime silicones based on methyl ethyl ketoxime ( MEKO ), although offering good adhesion and fast curing , release MEKO , the common name for 2-butanone oxime . This substance is suspected of being carcinogenic and there is an occupational exposure limit ( OEL ) on it in Germany .

However , Germany ’ s BG Bau ( employers ’ liability insurance association for the construction industry ) has determined in tests performed under realistic application conditions and involving several MEKO-releasing products , that during actual application this figure has invariably been exceeded by three to five times , even under good ventilation conditions . For this reason , BG Bau has determined that the ‘ STOP ’ principle needs to be applied in hazard assessment i . e . it recommends to first check whether MEKO-releasing products are at all necessary in the first place . If possible , they should be replaced by alternative sealant systems . Only if this is not

outstanding adhesion on virtually all substrates , whether concrete , glass , metal , wood or tiles

possible for technical reasons , says BG Bau , may the use of MEKO-releasing products be considered .

In such cases , the wearing of protective gloves and a protective respiratory mask is additionally required . The latter must also be worn post application until concentrations safely fall below the OEL . Depending on the ventilation and the type of room involved , this can take several days .

Because of this situation , Germany ’ s Industrial Association for Sealants ( IVD ) has decided to substitute out MEKO-releasing products within the next two years . In addition , BG Bau recommends that the preventative measures described also be applied in the case of all other oxime silicones , as here too the suspicion of carcinogenic effects cannot be precluded .

Following extensive research , Henkel is already able to provide an innovative solution that can completely replace oximes while uniting all the advantages of a neutrally crosslinking sealant – Pattex FUSIONXLT Premium Neutral Silicone . This new silicone generation is able to ensure outstanding adhesion on virtually all substrates , whether concrete , glass , metal , wood or tiles .

Compliant with EN 15651 , Pattex FUSIONXLT Premium Neutral Silicone is also suitable for glazing systems and sanitary applications . The flexible material exhibits very good compatibility on most standard commercial coating systems . It has a shelf life of 18 months and is certified for use in both clean rooms and HVAC systems .

A true all-rounder , it is easy to use and can be ideally smoothed . Fast curing and miminal shrinkage complete its application profile .

Compared to oxime silicones , the product does not give rise to critical emissions – making it ideal for interior applications without restriction . The formulation is also suitable for external applications due to its UV stability and high weather resistance .