PTFE , MODIFIED /EXPANDED PTFE
UNIFLON , TOPCHEM , SIGMA , GYLON , GORETEX
UNIFLON , TOPCHEM , SIGMA , GYLON , GORETEX
PTFE (Polytetrafluoroethylene) is suitable for sealing duties with most chemical media
across the whole PH range; the exceptions being molten alkali metals, fluorine gas and
any substances that may generate these at the operating temperatures and pressures
involved. It has an operating temperature range of -200 Deg C to 250 Deg C.
In addition to chemical resistance pure or virgin PTFE is well suited in FDA applications
where process contact with foodstuffs is required. Having a very low co-efficient of
friction, PTFE can also be used for slide bearings, non-stick applications and can be bonded to various substrates if the bonded surface is chemically
etched.
Pure PTFE under certain process conditions is not always dimensionally stable and can
creep or cold flow under load,loosing gasket stress applied. PTFE Envelopes and Modified
or Expanded PTFE materials have been developed to suitably reduce these effects.
PTFE Envelopes can be manufactured to fit most soft cut gasket materials in all
thicknesses and diameters, where the recovery of the protected gasket/composite gasket
compensates for the minimal creep associated with the thin wall section of the
envelope.
Whilst a multitude of fillers can be used, glass has evolved as the most common, improving both dimensional stability and wear resistance; it is readily available in either 15% or 25% filled options. Care must be taken in selection as the use of fillers can impair chemical resistance and in commercial, non-proprietary grades can often remove FDA compliance.
Modified (being reinforced or expanded) PTFE available
from SEP, represents the latest generation of multi-directional grade materials from
leading brand manufacturers such as KLINGER (TopChem), NOVUS (Uniflon),FLEXITALLIC
(Sigma), WL Gore (Gore-Tex), GARLOCK (Gylon).
- Outstanding chemical resistance
- Improved creep resistance properties
- Extremely low gas permeability
- Wide service temperature range
- Excellent sealing performance, even at low seating stress
- Conforms well to glass lined, ceramic, plastic coated and irregular/uneven
flanges
- Conforms to FDA regulations
- Environmentally friendly
- Easy to cut, handle and remove from flanges after service
- Up to 2000mm diameter one piece gaskets
- ’Fire-safe’ grade
No single material will have all the desired properties, indeed some properties may only
exist in one grade, therefore please contact our technical sales team for selection
assistance of sheet materials, cut gaskets and available tape types and sizes.
