DuPont™ Teflon® PTFE (polytetrafluoroethylene) granular molding powders are ideal for molding many different products and stock shapes, such as rods, tubes, and sheets. Products fabricated from Teflon® PTFE stock shapes are unaffected by nearly all chemicals and feature superior electrical properties. These products, some of which are rated for continuous service at 260°C (500°F), also provide exceptional low-temperature toughness, plus unique adhesion and flame resistance.
Processing
Teflon® PTFE granular molding powders are processed by preparing a preform, sintering the preform, and then fabricating functioning machined parts from the sintered stock shape. Filled compounds are easily produced from DuPont PTFE granular powders by mixing 5% to 60%, by weight, of inorganic fillers that selectively enhance properties.
Preforming
Adequate preform pressures are required to maximize end-use performance. Typical pressures range from 3,000 to 4,500 psi with dwell times varying with preform size. Stock shapes preformed at lower pressures exhibit inferior physical properties (specific density, tensile strength, elongation, flex life), electrical properties, and permeation and chemical resistance.
Sintering
Adequate sintering requires a programmable oven. The temperature is slowly raised from room temperature to 363° to 382°C (685° to 720°F). Hold times at these temperatures vary with part geometry and dimensions. The oven temperature is then slowly lowered to room temperature. Stock shapes that are not properly sintered exhibit inferior physical properties (specific density, tensile strength, elongation, flex life), electrical properties, and permeation and chemical resistance.
Grades and Applications
| Teflon® PTFE Grade |
Fine Cut Resins |
Applications |
7A
[.pdf] |
Finely divided 35-micron particles. 460-g/L bulk density. Up to 5,500 psi in tensile strength. Maximum granular PTFE chemical resistance. Parts fabricated from this resin have excellent physical and electrical properties. |
- High-performance mechanical and electrical applications requiring excellent end-use performance
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7C
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Finely divided "fluffy" 20-micron particles. 250-g/L bulk. Up to 5,900 psi in tensile strength. Often used in applications requiring excellent flex life. Parts fabricated from this resin have excellent physical and electrical properties. |
- Expansion joints
- Bellows
- Piston rings
- Diaphragms
- Skived film and sheet
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| Teflon® PTFE Grade |
Pelletized Resins |
Applications |
8
[.pdf] |
Pelletized 640-micron particles. 730-g/L bulk density. Up to 4,400 psi in tensile strength. Resin particles have hard surfaces and require higher preform pressures. Parts fabricated from this resin have superior physical and electrical properties. |
- Ball valve seats, seals, and discs
- Labware
- Small Parts
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| 8A |
Pelletized 510-micron particles. 690-g/L bulk density. Up to 4,480 psi in tensile strength. Resin particles are preformed using lower preform pressures. Parts fabricated from this resin have superior physical and electrical properties. |
- Isostatic molding
- Skived sheet
- Tank and pipe linings
- Ducting and expansion joints
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860
[.pdf] |
Offers superior powder flow, low mold shrinkage, and high bulk density.
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Teflon®
PTFE Grade |
Modified Resins |
Applications |
NXT 70
[.pdf]
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A fine-cut resin designed for
compression molding of blocks and sheets and for use as a base resin for compounds.
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NXT 75
[.pdf] |
A fine-cut resin designed for
general compression molding of blocks and sheets and for use as a base resin for compounds.
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seal rings valve seats bearing pads linings encapsulations base resin for filled compounds
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NXT 85
[.pdf]
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Chemically modified free-flow granular molding resin can be converted to parts by isostatic, billet, and sheet molding methods, as well as ram extrusion.
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