Sikaflex®-953 L15
Fast-curing two-component STP assembly adhesive / sealant
Sikaflex®-953 L15 is a 2-component Silane Terminated Polymer (STP) assembly adhesive which cures by chemical reaction of the two components. Owing to its good weathering resistance and gap-filling performance it can also be used for exterior sealing joints. It is as well suitable where pumping over a long distance is required.
- Pumpable over long distances
- Minimal pre-treatment required for most common substrates
- Solvent- and isocyanate-free
- Good gap-filling capabilities
- Great weathering and ageing resistance
PRODUCT BENEFITS
- Pumpable over long distances
- Minimal pre-treatment required for most common substrates
- Solvent- and isocyanate-free
- Good gap-filling capabilities
- Great weathering and ageing resistance
Areas of Application
Sikaflex®-953 L15 is suitable for bonding components exposed to dynamic stress and where the attainment of early strength is required. Common substrates 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 L15 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.Packaging
Sikaflex®-953 L15
| Dual cartridge | 490 ml |
| Mixer: MFHX 13-18T by medmix |
Sikaflex®-953 L15 (A)
| Pail | 23 l |
| Drum | 195 l |
Sikaflex®-905 (B)
| Pail | 23 l |
Product Details
| Properties |
| ||||
| Chemical base | 2-component silane terminated polymer (STP) | ||||
| Color (CQP001-1) |
| ||||
| Density (uncured) |
mixed |
| |||
| Mixing ratio | A:B by volume A:B by weight | 10 : 1 11.7 : 1 | |||
| Non-sag properties (CQP061-1) | Fair | ||||
| Application temperature | product, ambient | 5 ─ 40 °C | |||
| Skin time (CQP019-1) | 20 minutes A | ||||
| Open time (CQP526-1) | 15 minutes A | ||||
| Curing speed (CQP046-1) | (see table) A | ||||
| Shrinkage (CQP014-1) | 2 % | ||||
| Shore A hardness (CQP023-1 / ISO 48-4) | 50 | ||||
| Tensile strength (CQP036-1 / ISO 527) | 2.5 MPa | ||||
| Elongation at break (CQP036-1 / ISO 527) | 400 % | ||||
| Tear propagation resistance (CQP045-1 / ISO 34) | 15 N/mm | ||||
| Tensile lap-shear strength (CQP046-1 / ISO 4587) | 1.5 MPa | ||||
| Thermal resistance (CQP 513-1) | 1 hour | 160 °C | |||
| Service temperature (CQP513-1) | -45 ─ 90 °C | ||||
| Shelf life (CQP016-1) | 9 months B | ||||
| Mixer | for dispensing systems | Statomix® MS 13-18-G |
| CQP = Corporate Quality Procedure | A) 23 °C / 50 % r. h. | B) storage between 5 and 25 °C, comp. (B) is frost sensitive |
CURE MECHANISM
The curing of Sikaflex®-953 L15 takes place by chemical reaction of the two components.
| Time [h] | Strength [MPa] |
| 2 | 0.4 |
| 4 | 0.9 |
| 6 | 1.1 |
Table 1: Lap shear strength (CQP 046-1) at 23 °C / 50 % r.h.
CHEMICAL RESISTANCE
Sikaflex®-953 L15 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. 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 L15 can be processed by cartridge or with a suitable dispensing system. The mixer type needs to be respected. For dispensing systems the mixer type is stated in the Typical Product Data table, whereas for cartridges it is stated under Packaging Information.
Sikaflex®-953 L15 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 the Product 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.
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 L15 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 L15 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.