Sikaflex®-258
Primerless windscreen adhesive
Sikaflex®-258 is a cold applied, primerless to glass windshield adhesive, optimized for manual application. It provides a long open time and ensures safe application even under warm conditions.
Note: Primerless to glass application requires the glass to be prepared using an Automotive grade glass cleaner such as Sika® CleanGlass. The bonding surfaces must be free of contamination and have proper UV protection, such as a ceramic frit.
- Easy to extrude with manual application gun
- Primerless to glass adhesion
- Good bead stability and non-sag properties
- Short cut-off string
PRODUCT BENEFITS
- Solvent free, no odor
- Easy to extrude with manual application gun
- Primerless to glass adhesion
- Good bead stability and non-sag properties
- Short cut-off string
Usage
Sikaflex®-258 is suitable for experienced professional users only.This product and related process information is designed for Automotive Glass Replacement. For other applications, tests with actual substrates and conditions have to be performed to ensure adhesion and material compatibility.
Packaging
| Cartridge | 310 ml |
Product Details
| Chemical base | 1-component polyurethane | |
| Colour (CQP001-1) | Black | |
| Cure mechanism | Moisture-curing | |
| Density (uncured) | 1.31 kg/l | |
| Non-sag properties (CQP061-1) | Good | |
| Application temperature | ambient, product | 5 ─ 40 °C |
| Skin time (CQP019-1) | 40 minutes A | |
| Open time (CQP526-1) | 30 minutes A | |
| Curing speed (CQP049-1) | (see diagram) | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 50 | |
| Tensile strength (CQP036-1 / ISO 527) | 4.5 MPa | |
| Elongation at break (CQP036-1 / ISO 527) | 450 % | |
| Tensile lap-shear strength (CQP046-1 / ISO 4587) | 3.0 MPa | |
| Minimum Drive Away Time (cars) according FMVSS 212 (CQP511-1) | with airbags | 3 hours A, B |
| Shelf life | 9 months C |
| CQP = Corporate Quality Procedure | A) 23 °C / 50 % r. h. | B) details about MDAT contact Sika | C) stored (unopened) in a dry place at ≤ 25 °C |
CURE MECHANISM
Sikaflex®-258 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 Sikaflex®-258
CHEMICAL RESISTANCE
Sikaflex®-258 is generally resistant to fresh water, seawater, diluted acids and diluted caustic solutions; temporarily resistant to fuels, mineral oils, vegetable and animal fats and oils; not resistant to organic acids, glycolic alcohol, concentrated mineral acids and caustic solutions or solvents.
Application
Surface preparation
Surfaces must be clean, dry and free from grease, oil, dust and contaminants.
The bond faces must be prepared with an Automotive grade glass cleaner such as Sika® CleanGlass. Sikaflex®-258 is capable to bond on glass and ceramic frits without additional pre-treatment. It is compatible with Sika's Black-Primerless or All Black installation process.
Glass without ceramic coatings need proper UV protection.
Application
Sikaflex®-258 can be processed between 5 °C and 40 °C but changes in reactivity and application properties have to be considered. The optimum temperature for substrate and adhesive is between 15 °C and 25 °C.
It is recommended to apply the adhesive with a piston-type application gun.
Consider that the viscosity will increase at low temperature. For easy application, condition the adhesive at ambient temperature prior to use.
To ensure a uniform thickness of the bondline it is recommend to apply the adhesive in form of a triangular bead (see figure 1).
Figure 1: Recommended bead configuration
The open time is significantly shorter in hot and humid climate. The glass must always be installed within the open time. Never install a glass after the product has built a skin.
Removal
Uncured Sikaflex®-258 can be removed 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 or a suitable industrial hand cleaner and water.
Do not use solvents on skin.