Aptflex F21
A two-part, high-performance encapsulation material, exhibiting toughness, excellent hydrolytic stability and an acoustic wave speed similar to that of seawater.
Overview
Aptflex F21 is a two-part, high-performance encapsulation material, exhibiting toughness, excellent hydrolytic stability and an acoustic wave speed similar to that of seawater.
These properties make Aptflex F21 an ideal system for hydrophone potting, marine encapsulation applications or as an acoustic window.
Aptflex F21 is particularly useful where small delicate components are potted since the material exhibits low shrinkage and hence stress during the cure phase.
Key features
- Flexibility and resistance to temperature extremes of -50 °C to 100 °C
- Low moisture sensitivity during the cure phase
- Excellent hydrolytic stability
- Excellent electrical insulation properties
- Acoustic wave speed similar to that of seawater
- Very low insertion loss
Tutorial on mixing acoustic materials
Technical specifications
| Appearance | Black |
| Density part A | 0.91 g/ml |
| Density part B | 1.22 g/ml |
| Mix ratio | 3.35:1 (By Weight A:B) |
| Cured density | 1.050 g/ml |
| Initial mixed viscosity | 50 poise at 25 °C |
| Usable life | 25 minutes at 25 °C |
| Gel time | 50 minutes at 25 °C |
| Curing times*: | 24 to 48 hours at 25 °C Overnight 30 °C 5 hours at 50 °C 3 hours at 80 °C |
| Hardness | 80 to 85 Shore A |
| Tensile strength | 12 MPa |
| Elongation at break | 300% |
* Curing times are temperature dependant. Precision Acoustics reserves the right to change the specification without notice.
** Minimum order quantities apply if there is no stock or if longer expiry dates are required.
The shelf-life of unopened containers is at least 12 months.