adhesives and sealants
SIPERNAT® speciality Silica for Adhesives and Sealants
Specialty Silica is one of the most flexible active ingredients for adhesives & sealants applications.
The key functions of Evonik Industries AG speciality silica are rheology control, reinforcement, flow improvement and stabilization for adhesives and sealants.
Evonik offers tailormade specialty silica for adhesives and sealants, for example specialty silica with very high specific surface areas and hydrophobic specialty silica.
SIPERNAT® 22 LS
SIPERNAT® 22 LS is often used as thickener and thixotrope for liquid systems, such as body repair adhesives, which are based mainly on polyester or epoxy resins.
Furthermore, SIPERNAT® 22 LS can be used successfully as thixotrope in polyacrylate sealants.
Finally, SIPERNAT® 22 LS is used also as free flow and anti-caking agent in hotmelt powders and granulate.
SIPERNAT® 22 LS is a very fine particle silica with a high specific surface area of 175 m2/g.
SIPERNAT® 22 LS should be used at concentrations for body repair adhesives between 4 - 6 wt.-percent.
Body filler putties with SIPERNAT® 22 LS display superior levelling and a pinhole free surface after sanding, for example no porosity, compared to other thixotropes.
In polyacrylate sealants, SIPERNAT® 22 LS should be used at concentrations of 3 - 6 wt.-percent.
As free flow and anti-caking agent, SIPERNAT® 22 LS should be used at a dosage of 0.2 - 0.5 wt.-percent silica.
As a starting point, the silica particle size used should be 1/8 to 1/10 of the powder. Thus, the processability and handling of adhesives powders and granulates are improved.
SIPERNAT® 22 can be used as active reinforcing filler in butyl tapes and sealants. Additionally, SIPERNAT® 22 shows better sound dampening properties than carbon black.
SIPERNAT® 22 has a particle size of 110 micrometer and a tamped density of 260 g/l. As a result, SIPERNAT® 22 shows an excellent wet-in behaviour in butyl polymers and can be used at high loading levels up to 20 wt.-percent.
SIPERNAT® 500 LS
SIPERNAT® 500 LS can be used as thickener and thixotrope for liquid systems.
SIPERNAT® 500 LS is especially suitable for transparent applications, for example as thickener and thixotrope for transparent polyacrylate sealants.
Furthermore, SIPERNAT® 500 LS can partly substitute fillers like chalk or clay used in hotmelt adhesives. Finally, also SIPERNAT 500 LS can be used as highly effective flow aid and excellent anti-caking agent for fine powders.
SIPERNAT® 500 LS is a very fine particle silica with a high specific surface area of 450 m2/g.
The suggested concentrations of SIPERNAT® 500 LS in liquid adhesives & sealant systems are 4 wt.- percent to 8 wt.-percent.
SIPERNAT® 500 LS reduces the cold flow and improves the mechanical properties in hotmelt adhesives.
The suggested concentrations of SIPERNAT® 500 LS as free-flow aid and anti-caking agent are 0.2 - 0.5 wt.-percent.
SIPERNAT® D 10
SIPERNAT® D 10 can be used successfully as active reinforcing filler in sealants, for example polysulfide or polyurethane sealants.
Additionally, SIPERNAT® D 10 improves the sag resistance of the uncured sealants.
SIPERNAT® D 10 is a very fine particle silica which has a high hydrophobicity.
SIPERNAT® D 10 should be used with 5 - 15 wt.-percent loadings levels in polysulfide and polyurethane sealants.
SIPERNAT® 880 can be used as stabilizing agent in polychloroprene adhesives which are used for the furniture and shoe industry.
SIPERNAT® 880 is a calcium silicate. SIPERNAT® 880 has a pH value of 10.5 and neutralizes arising hydrochloride acid. As a result, the stability of the polychloroprene adhesive is improved.
Suggested dosages are 8 - 12 wt.-percent of SIPERNAT® 880.
Technical Bulletin 63: AEROSIL® Fumed Silica and SIPERNAT® in Sealants
(pdf, 623 KB)
This Technical Bulletin describes the production process for fumed and precipitated silicas. Each silica type is categorized according to the different sealant systems with attainable effects, silica concentration in percent and suitable incorporation processes. The Bulletin also discusses silicone sealants, polysulphide, polyurethane sealants and PVC-plastisols. There are also standard formulations and a list of physico-chemical data.