Sikaflex®-232 US
Elastic adhesive/sealant with high green strength
Sikaflex®-232 US is a 1-component, thixotropic, polyurethane adhesive / sealant that exhibits a high initial green strength. It adheres well to a wide variety of substrates and cures on exposure to atmospheric moisture.
- Very good sag resistance
- Bonds well to a wide variety of substrates
- Good gap-filling properties
- Can be painted and sanded
- Low odor
PRODUCT BENEFITS
- Very good sag resistance
- Bonds well to a wide variety of substrates
- Good gap-filling properties
- Can be painted and sanded
- Low odor
Usage
Sikaflex®-232 US is suitable for sealing and simple bonding applications where high green strength is required to improve the assembly process such as trailers, RV’s, industrial assembly and HVAC units. Sikaflex®-232 US adheres well with the most common substrates in these applications such as metals, metal primers and paint coatings (2-component systems), fiber reinforced plastic (FRP), and wood.Seek manufacturer’s advice and perform tests on original substrates before using Sikaflex®-232 US on materials prone to stress cracking. This product is suitable for experienced professional users only. Test with actual substrates and conditions have to be performed ensuring adhesion and material compatibility.
Packaging
| Cartridge | 300 ml |
| Unipack | 600 ml |
| Drum | 53 gal (US) |
Product Details
| Chemical base | 1-component polyurethane | |
| Color (CQP001-1) | White | |
| Cure mechanism | Moisture-curing | |
| Density (uncured) | 1.27 kg/l (10.6 lb/gal) | |
| Non-sag properties | Good | |
| Application temperature | 5 ─ 35 °C (41 ─ 95 °F) | |
| Skin time (CQP019-1) | 35 minutes A | |
| Curing speed (CQP049-1) | (see diagram 1) | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 40 | |
| Tensile strength (ASTM D412) | 1.5 MPa (220 psi) | |
| Elongation at break (ASTM D412) | 500 % | |
| Service temperature (CQP513-1) | -40 ─ 90 °C (-40 ─ 194 °F) | |
| Shelf life | cartridge / unipack drum | 9 months B 6 months B |
| CQP = Corporate Quality Procedure | A) 23 °C (73 °F) / 50 % r. h. | B) storage below 25 °C (77 °F) |
CURE MECHANISM
Sikaflex®-232 US 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 for Sikaflex®-232 US
CHEMICAL RESISTANCE
Sikaflex®-232 US 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 and dust.
Surface treatment depends on the specific nature of the substrates and is crucial for a long lasting bond. Suggestions for surface preparation may be found on the current edition of the appropriate Sika® Pre-Treatment Chart. Consider that these suggestions are based on experience and have in any case to be verified by tests on original substrates.
Application
Sikaflex®-232 US can be processed at temperatures (climate and product) between 5 °C and 35 °C (41 °F and 95 °F) but changes in reactivity and application properties have to be considered. The optimum temperature for substrate and sealant is between 15 °C and 25 °C (59 °F and 77 °F).
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
Sikaflex®-232 US can be processed with manual, pneumatic or electric driven piston guns. The open time is significantly shorter in hot and humid climate. The parts must always be installed within the open time. Never join bonding parts if the adhesive has built a skin.
Tooling and finishing
Tooling and finishing must be carried out within the skin time of the product. It is recommended using Sika® Slick. Other finishing agents must be tested for suitability and compatibility prior the use.
Removal
Uncured Sikaflex®-232 US may 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 a suitable industrial hand cleaner and water.
Do not use solvents on skin.
Overpainting
Sikaflex®-232 US can be painted after formation of a skin. If the paint requires a baking process, best performance is achieved by allowing the sealant to fully cure first.
1C-PUR and 2C-acrylic based paints are usually suitable. All paints have to be tested by carrying preliminary trials under manufacturing conditions.
The elasticity of paints is usually lower than that of sealants. This could lead to cracking of the paint in the joint area.