Tonsan STP1921 is a high quality, neutral, elastic single component adhesive/sealant based on Silane-terminated Polymer, which cures by reaction with moisture to an elastic product. The skin formation and curing time are dependent on humidity and temperature, and the curing time also depends on joint depth. By increasing the temperature and moisture these time can be reduced; low temperature as well as low moisture retard the process. STP 1921 is a good compromise between an adhesive and a sealant based on Silane-terminated Polymer. STP 1921 is suitable for elastic seal which also high strength is required. STP 1921 is odourless and free of solvents, isocyanates, silicones and PVC. It demonstrates good adhesion without primer to many substrates and is compatible with suitable paint systems. The sealant also demonstrates good UV resistance and therefore can be used for interior and exterior applications.

RTU Product Type: 1K (1 component) Sealant, Joint Sealant, Seam Sealant

Application Area: Air Conditioning , Apparatus Components, Caravans, Containers, Electrical Applications, Joints, Railway Carriage, Solar Energy System, Vehicle Body, Ventilation Systems

Compatible Substrates & Surfaces: Metal, Plastics, Poly(Methyl Methacrylate) (PMMA), Polycarbonate (PC)

Chemical Family: Silane-terminated Polymers

Features: Elastic Bonding, Excellent Primerless Adhesion, Good Color Stability, High Strength, Non Corrosive, Non-Sagging, Odorless, Thixotropic, UV Resistant

Technical Data Sheet
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Enhanced TDS

Identification & Functionality

Features & Benefits

Applications & Uses

Markets
Applications
Application Area
Compatible Substrates & Surfaces
Cure Method
Application Limitations

When bonding and sealing PMMA and polycarbonate, under tension, stress corrosion cracking may occur. In such cases STP 1921 should not be utilized.

Paintability Information

STP1921 may be over-painted, however due to the large number of paints and varnishes we strongly recommend a compatibility test before application. The drying time of alkyd resin based paints may increase.

Application Instructions
  • The substrates must be clean, dry, free of oil and grease.
  • Sausage is applied with the corresponding Hand or Air pressure pistols.
  • In the case of compressed air application, a pressure of (0.2-0.4) MPa is required.
  • After application, STP1921 can be smoothed with soapy water.
Typical Applications
  • Elastic bonding of metals and plastics.
  • Elastic, interior and/or exterior seam and joint sealing.
  • In the following areas: vehicle body, caravan, railway carriage, container, general metal and apparatus construction; the electrical, plastics, air-conditioning and ventilation industries.

Properties

Physical Form
Appearance
White/Black/Gray thixotropic paste
Technical Data
ValueUnitsTest Method / Conditions
Sag ResistanceNo sagging--
Specific Densityapprox. 1.45--
Skin Formation Time (at 23±2°C, 50±5 % relative humidity)approx. 30min-
Cure Rate (at 23±2°C, 50±5 % relative humidity)approx. 3mm/24h-
Hardnessapprox. 35Shore AISO7619, GB/T531
Tensile Strengthapprox. 1.8MPaISO37, GB/T528
Elongation (Break)approx. 350%ISO37, GB/T528
Application Temperature5 - 40°C-
Operating Temperature-50 to 90°C-
Short Exposure120°C-
Storage Temperature8 - 28°C-
Adhesion Information

STP 1921 has been tested and found to have excellent adhesion to the following unprimed substrates: aluminum, acrylic-coated aluminum, brass, steel, stainless steel, glass, fiberglass, ABS, rigid PVC, polyester and etc. Depending on the surface it can be necessary to roughen the surface or to use a primer as an adhesion promoter to provide optimum adhesion.

Packaging & Availability

Regional Availability
  • North America

Storage & Handling

Shelf Life
12 months
Storage Condition

Shelf-life: 12 months in original packaging