Sikasil® WT-40
High-performance, 1-component window bonding adhesive
Sikasil® WT-40 is a 1-component, neutral-curing structural silicone adhesive with very high mechanical strength, for structural bonding of insulating glass units into window frames and for back-bedding applications.
- Excellent adhesion to a wide variety of substrates
- Outstanding UV and weathering resistance
- Very high mechanical strength
- Good gap-filling capabilities
- Remains flexible over a wide temperature range
- Long-term durability
PRODUCT BENEFITS
- Excellent adhesion to a wide variety of substrates
- Outstanding UV and weathering resistance
- Very high mechanical strength
- Good gap-filling capabilities
- Remains flexible over a wide temperature range
- Long-term durability
Areas of Application
Sikasil® WT-40 has a wide adhesion range on many substrates such as glass, (coated) metal, wood, PVC and many other substrates. In combination with its good mechanical properties, especially the high modulus of elasticity, this makes the adhesive most suitable for structural bonding of insulating glass units into window frames and for back-bedding applications. It is further suitable for highly demanding industrial bonding and sealing applications. This product is suitable for experienced professional users only. Tests with actual substrates and conditions have to be performed ensuring adhesion and material compatibility.Product Details
| Chemical base | 1-component silicone | |
| Color (CQP001-1) | Black, grey S6, white S3 | |
| Cure mechanism | Moisture-curing | |
| Cure type | Neutral | |
| Density (uncured) | 1.36 kg/l | |
| Non-sag properties (CQP061-4 / ISO 7390) | Good | |
| Application temperature | ambient | 5 ─ 40 °C |
| Skin time (CQP019-1) | 20 minutes A | |
| Tack free time (CQP019-3) | 180 minutes A | |
| Curing speed (CQP049-1) | (see diagram) | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 40 | |
| Tensile strength (CQP036-1 / ISO 527) | 2.1 MPa | |
| 100 % modulus (CQP036-1 / ISO 527) | 0.9 MPa | |
| Elongation at break (CQP036-1 / ISO 527) | 400 % | |
| Tear propagation resistance (CQP045-1 / ISO 34) | 7 N/mm | |
| Service temperature | -40 ─ 150 °C | |
| Shelf life | 9 months B |
| CQP = Corporate Quality Procedure | A) 23 °C / 50 % r. h. | B) storage below 25 °C |
CURE MECHANISM
Sikasil® WT-40 cures by reaction with atmospheric moisture. At low temperatures the water content of the air is generally lower and the curing reaction proceeds somewhat slower (see diagram 1).
Diagram 1: Curing speed Sikasil® WT-40
Application
Surface preparation
Surfaces must be clean, dry and free from grease, oil and dust. Surface treatment depends on the specific nature of the substrates and is crucial for a long lasting bond.
Application
The optimum temperature for substrate and sealant is between 15 °C and 25 °C.
Sikasil® WT-40 can be processed with hand, pneumatic or electric driven piston guns as well as pump equipment. For advice on selecting and setting up a suitable pump system, contact the System Engineering Department of Sika Industry.
Joints must be properly dimensioned.
Basis for calculation of the necessary joint dimensions are the technical values of the adhesive and the adjacent building materials, the exposure of the building elements, their construction and size as well as external loads.
Joints deeper than 15 mm must be avoided.
Tooling and finishing
Tooling and finishing must be carried out within the skin time of the sealant or adhesive.
When tooling freshly applied Sikasil® WT-40, press the adhesive to the joint flanks to get a good wetting of the bonding surface. No tooling agents must be used.
Removal
Uncured Sikasil® WT-40 may be re-moved from tools and equipment with Sika® Remover-208 or another suitable solvent. Once cured, the material can only be removed mechanically.
Hands and exposed skin have to be washed immediately using hand wipes such as Sika® Cleaner-350H cleaning towels or a suitable industrial hand cleaner and water. Do not use solvents on skin.
Overpainting
Sikasil® WT-40 cannot be overpainted.
Application limits
Recommended solution from Sika for structural glazing and window bonding are usually compatible to each other. These solutions consist of products such as Sikasil® SG, IG, WS and WT series. For specific information regarding compatibility between various Sikasil® products and other Sika products contact the Technical Department of Sika Industry.
To exclude materials influencing Sikasil® WT-40, all materials such as gaskets, tapes, setting blocks, sealants, etc., in direct and indirect contact have to be approved by Sika in advance.
Where two or more different reactive sealants are used, allow the first to cure completely before applying the next one.
The above mentioned Sika process materials may only be used in structural glazing or window bonding applications after a detailed examination and written approval of the corresponding project details by Sika Industry.