Paste extrusion

TFE-Fluorocarbon Resins Paste Extrusion of Wire Insulations, buUetia, E.I. du Pont de Nemours Co., Inc., Wilmington, Del., 1961. [Pg.357]

Passive heat-transfer enhancement techniques, retrofitted, 13 267 Passive mixers, in microfluidics, 26 966, 967 Passive noise detectors, 11 673 Passive nondestructive tests, 17 416, 425 Passive reactors, 17 555 Passive sensing materials, 22 706-707 Passive smart textiles, 24 625 Passive solar collection, silica aerogel application, 1 761-762 Pasta products, 26 278 Paste-extrusion process, 18 301-302 Paste forming, ceramics, 5 651 Paste inks, 14 315-316... [Pg.675]

PTFE sintering, pressing, ram or paste extrusion, compression moulding or isostatic moulding, machining, hot stamping, extrusion of pre-sintered powders on special machines. [Pg.480]

High reduction Paste extrusion Agglomerated powder Wire coating, thin-walled tubing... [Pg.254]

Low reduction ratio Paste extrusion Agglomerated powder Thread-sealant tape, pipe liners, tubing, porous structures... [Pg.254]

The ability to dr aw approximately 100 - A diameter fibrils from PTFE dispersion particles, either by fracture after cold compaction [34] or by uniaxial or biaxial expansion of sheets or tubes after paste extrusion (extrusion of mixtures of the dispersion particles and lubricants such as mineral spirits) and lubricant removal [35], was demonstrated a number of years ago. The former process results in the development of a myriad of fibrils spanning the gap between the fracture faces these were utilized for ED characterization of the PTFE conformation and crystal packing. [Pg.142]

FIGURE 25.30 Images for -AljOj hollow fibers obtained by ceramic paste extrusion (a) cross-section morphology, (b) surface morphology. (From Pan, X.L., Stroh, N., Brunner, H., Xiong, G.X., and Sheng, S.S., Separation Purification Technology, 32, 265, 2003.)... [Pg.475]

Wet mass rheology heavily impacts performance through controlling both developed pressures and extrusion through the die, as in the case of paste extrusion (see Paste Extrusion and Screw and Other Paste Extruders subsections). In addition, the developed pressure in the roller nips behaves in a similar fashion to roll presses (see Roll Presses subsection). [Pg.2381]

The formation of defects and phase separation is an important consideration in paste extrusion. Typical defects include lamination or delamination (occurring with joining of adjacent past streams) and surface fracture, often referred to as shark-skin formation. Surface fracture generally increases with decreasing paste liquid... [Pg.2383]

Metal powder processing techniques in which a preform is molded and sintered are used to process PTFE. Compression molding may also be used to fabricate PTFE parts. Its dispersions are applied by similar techniques to other coatings. Paste extrusion in which PTFE is blended with a hydrocarbon, prior to molding a preform, is used to continuously fabricate PTFE into tubes, tapes, and wire insulation. The hydrocarbon is vaporized before the parts are sintered. PVF is dispersed in a polar latent solvent such as dimethyl acetamide and is melt-extruded as a plastisol, followed by solvent removal by drying. [Pg.1039]

Fine Powder PTFE -CF2-CF2- 327 10lO iol2(3) Paste extrusion... [Pg.12]

Fine powder PTFE is fabricated by paste extrusion, where PTFE powder is first blended with a hydrocarbon lubricant (hence the term paste) which acts as an extrusion aid. It is then formed into a cylindrical preform at a fairly low pressure (1-3 MPa) and placed inside the barrel of a ram extruder where it is forced through a die at a constant ram rate. The ex-trudate is passed through multiple ovens and a cooling device where it is first dried, then sintered, and finally cooled. The lubricant can also be removed by extraction in a hot solvent bath.l ... [Pg.174]

A major requirement of paste extrusion is that, up to the point of sintering and coalescence, the ex-trudate must possess sufficient strength to withstand the extensive handling that takes place during the process. The tendency of fine powder to fibrillate (form a web of strong filaments between particles) when extruded provides the needed strength and the unique characteristics of fine powder articles. [Pg.174]

Reduction ratio, the ratio of the cross sectional surface areas of the preform and the extrudate, is an important variable in paste extrusion. For a given extruder barrel, the smaller the cross section of the final product, the higher the reduction ratio. The size of the preform can be varied in a fairly limited range, therefore, resins must be able to undergo the reduction during extmsion. Different fine powder grades have been developed by suppliers to accommodate the wide range of reduction ratios of commercial operations. [Pg.174]

Paste extrusion should take plaee at above 30°C which is another transition temperature of the pol mier. [Pg.175]

In a paste extrusion line for wire insulation, the wire is passed through the paste extmder where it is coated with PTFE while moving through the die. It... [Pg.177]

Lined pipe Isostatic molding, melt extrusion, paste extrusion PTFE, PVDF, PFA, ETFE, ECTFE... [Pg.317]

Hoses and expansion joints Paste extrusion, melt extrusion PTFE, PFA, FEP, ETFE... [Pg.317]

Dispersion-pol5unerizedpolytetiafluoroethylene powder is processed by paste extrusion in which the pol5uner is mixed with a hydrocarbon lubricant. These petroleum-based lubricants have low flash points posing potential fire hazards. Lubricants... [Pg.389]

Teflon 62 Polytetrafluoroethylene (PTFE) fine powder, paste extrusion resin. [Pg.421]

Abused Particles - Particles of fine powder (dispersion or emulsion polymerized) polytetrafluoro-ethylene subjected to shear resulting in fibrillation during handling and transportation prior to paste extrusion. [Pg.521]

Paste Extrusion - Process by which dispersion po-l5mierized polytetrafluoroethylene (PTFE) is extruded with the aid of a hydrocarbon lubricant. A paste of the PTFE and hydrocarbon is made... [Pg.535]

Reduction Ratio - This factor is the ratio of cross-sectional surface areas of the preform and the extrudate in paste extrusion. Different dispersion polymerized polytetrafluoroethylene powders accommodate different reduction ratio ranges. In general, reduction ratio of the resin decreases as molecular weight increases. Melt fracture and defects appear in the extrudate if it is processed at above its maximum reduction ratio. [Pg.542]

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