SR635 Natural Rubber Lining
This natural gum rubber lining material is meant for use for HCl service. It is FDA Compliant.
Lining Specifications
Lining Code: SR635
Type: Natural
Tie Gum: Without Tie Gum
Properties: Durometer 35 +/-5 Shore A – Natural, soft, neutral color, pure gum rubber with no Tie Gum. Use for HCl service. FDA Compliant.
Note: Natural rubber will “weather check” (prematurely degrade) if exposed to sunlight, ozone, and oxygen.
Primers and Adhesive System:
- One coat Chemlok® 289 on Metal
- One coat Chemlok® 290 on Metal
- One coat Chemlok® 286 on Metal
- One coat Chemlok® 286 on Lining
Cure Time and Temperature
Cure for thickness up to ¼”
| Pressure, Saturated Steam (Autoclave) | 1 hour @ 260°F (127°C) |
| Internal Steam Cure | 2 hrs. @ 235°F (112°C) for properly insulated vessels. 4 hrs @ 235°F(112°C) for non-insulated vessels. |
| Atmosphere Steam Cure | 24 hrs. @ 190°F-205°F (87°C-96°C) |
Note: All reference to cure psi represents gauge pressure.
**Cure times may require tuning to compensate for low temperatures, heavy metal thicknesses, and other anomalies. Contact SRR Technical Department for recommendations on lining thicknesses over ¼”.
Storage
Ideal storage temperature is 50°F not to exceed 85°F and shelf life is 180 to 45 day range respectively.
Depending on storage conditions it may be possible to use rubber linings beyond shelf life. Please contact Salem-Republic Rubber Company for technical advisement before usage.
Designed Physical Properties
| Tensile Strength PSI | ASTM D412 | 2500 min |
| % Elongation at Break | ASTM D412 | 600 min |
| Durometer | ASTM D2240 | 35 +/- 5 |
| Specific Gravity | ASTM D297 | 0.95 |
| Adhesion to Metal | ASTM D429 | 30 pli min |
Skive: Open (Without Tie Gum)
Repair lining: Same or SR635
Application Suggestions
- Plying up lining thicker than 1/4″ is not recommended due to sagging during cure process.
- Warming rubber to approximately 120°F will aide in applying and is recommended.
- Over-curing is possible, if temperature specifications and cure times are exceeded, resulting in reversion.
- Experienced applicators may have techniques which produce equal or superior results and by no means are SRR’s application suggestions meant to replace these proven techniques.
Standard Dimensions
| Roll | Standard Gauge | Tolerance | Roll Gauge | Standard Roll | Maximum |
|---|---|---|---|---|---|
| A Roll | .120 | +/-.05 | A Roll | 90ft | 96 |
| B Roll | .180 | +/-.010 | B Roll | 60ft | 66 |
| C Roll | .240 | +.010 or -.020 | C Roll | 45ft | 51 |
| 3/8” Roll | .360 | +/-.015 | 3/8” Roll | 30ft | 33 |
| ½“ Roll | .480 | +/-.015 | ½“ Roll | 23ft | 27 |
*Customer specific gauges and widths, other than standard, are available upon request. Please call Salem-Republic Rubber Company at 1-877-425-5079 with any questions or more information about our Custom Elastomeric Linings.