Sikaflex®-953 AF
Fast-curing, fungus resistant 2-component STP assembly adhesive and sealant
Sikaflex®-953 AF is a 2-component Silane Terminated Polymer (STP) assembly adhesive which cures by chemical reaction of the two components. It largely prevents fungal and bacterial growth and meets hygiene requirements for ventilation and air-conditioning. Owing to its good weathering resistance and gap-filling performance it can also be used for exterior sealing joints. It is also very suitable where pumping over a long distance is required.
- Resistant to fungal and bacterial growth according DIN EN ISO 846: 1997-10
- Meets hygiene requirements for ventilation and air-conditioning systems and units according VDI 6022 Blatt 1:2011-07
- Great weathering and ageing resistance
- Adheres well to most common substrates with a minimal pre-treatment
- Solvent- and isocyanate-free
- Good gap-filling capabilities
- Pumpable over long distances
PRODUCT BENEFITS
- Resistant to fungal and bacterial growth according DIN EN ISO 846: 1997-10
- Meets hygiene requirements for ventilation and air-conditioning systems and units according VDI 6022 Blatt 1:2011-07
- Great weathering and ageing resistance
- Adheres well to most common substrates with a minimal pre-treatment
- Solvent- and isocyanate-free
- Good gap-filling capabilities
- Pumpable over long distances
Areas of Application
Sikaflex®-953 AF is designed for sealing and bonding of heat, ventilation and air conditioning units, where the attainment of early strength is required.Possible substrate materials are metals, particularly aluminum (including anodized), steel (including phosphated, chromated, galvanized), metal primers and paint coatings (2-part systems), ceramic materials and plastics.
Seek manufacturer’s advice and perform tests on original substrates before using Sikaflex®-953 AF on materials prone to stress cracking. 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
| Properties |
| ||||
| Chemical base | Silane terminated polymer (STP) | ||||
| Color (CQP001-1) |
mixed |
| |||
| Density (uncured) |
mixed (calculated) |
| |||
| Mixing ratio | A:B by volume A:B by weight | 10:1 11.7:1 | |||
| Non-sag properties (CQP061-1) | Fair | ||||
| Application temperature | 5 ─ 40 °C | ||||
| Skin time (CQP019-1) | 35 minutes A | ||||
| Snap time (CQP554-1) | 20 minutes A | ||||
| Curing speed (CQP046-1) | (see table) A | ||||
| Shrinkage (CQP014-1) | 2 % | ||||
| Shore A hardness (CQP023-1 / ISO 48-4) | 40 | ||||
| Tensile strength (CQP036-1 / ISO 527) | 2.5 MPa | ||||
| Elongation at break (CQP036-1 / ISO 527) | 350 % | ||||
| Tear propagation resistance (CQP045-1 / ISO 34) | 6 N/mm | ||||
| Tensile lap-shear strength (CQP046-1 / ISO 4587) | 1.4 MPa | ||||
| Thermal resistance (CQP 513-1) | 1 hour | 160 °C | |||
| Service temperature (CQP513-1) | -45 ─ 90 °C | ||||
| Shelf life | 9 months B | ||||
| Mixer | Statomix® MS 13-18 G |
| CQP = Corporate Quality Procedure | A) 23 °C / 50 % r. h. | B) storage below 25 °C |
CURE MECHANISM
The curing of Sikaflex®-953 AF takes place by chemical reaction of the two components.
| Time [h] | Strength [MPa] |
| 2 | 0.4 |
| 4 | 0.8 |
| 6 | 1.0 |
Table 1: Lap shear strength (CQP 046-1) at 23 °C / 50 % r. h.
CHEMICAL RESISTANCE
Sikaflex®-953 AF 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. All pre-treatment steps must be confirmed by preliminary tests on original substrates considering specific conditions in the assembly process.
Application
Sikaflex®-953 AF need to be processed with an adequate dispensing system. The mixer type needs to be respected (see table Typical Product Data).
Sikaflex®-953 AF can be applied between 5 °C and 40 °C 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. 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 parts must always be joint within the open time. As a rule of thumb, a change of + 10 °C reduces the open time by half.
Sikaflex®-953 AF is processed with pump equipment. For advice on selecting and setting up a suitable pump system, contact the System Engineering Department of Sika Industry.
Tooling and finishing
Tooling and finishing must be carried out within the open time of the adhesive. We recommend the use of Sika® Tooling Agent N. Other finishing agents must be tested for suitability and compatibility.
Removal
Uncured Sikaflex®-953 AF 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.
Overpainting
Sikaflex®-953 AF can be best painted within the skin formation time. If painting process takes place after the sealant has built a skin, adhesion could be improved by treating the joint surface with Sika® Aktivator-100 or Sika® Aktivator-205 prior to paint process. If the paint requires a baking process (> 80 °C), best performance is achieved by allowing the sealant to fully cure first. 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.