Extruded PVC

During 1989-1990, the Research Institute for Petrochemistry, Czechoslovakia developed extrudable PVC-wood (25 wt.%) composites using a twin-screw extruder, which produce 442 Ib/h and about 0.33 million Ib/year hardboards with approximately 0.25-0.85 cm ( /lo- /s in) thickness and 101.6 cm (40 in) wide (D. Maldas, personal communication, 1992.)... 

Windows and doors extruded PVC is used for doors and windows for houses, buildings, factories. Though the window and door market is fast growing (7.3% per year in the USA), the market share of plastics is only a few percent of the total US demand for windows and doors. 

Plastics can also be combined with other materials such as aluminum, steel, and wood to provide specific properties. Examples include extruded PVC/wood window frames and extruded plastic film/ aluminum-foil packaging material. All combinations may require that certain aspects of compatibility such as processing temperature, bondability, and coefficient of expansion or contraction exist. 

When extruding PVC, it is often preferred to meter the masterbatches or monobatches of the metallic pigment directly into the extruder. 

RELATIONSHIPS BETWEEN MELT FLOW AND MECHANICAL PROPERTIES OF EXTRUDED PVC PROFILES FOR WINDOW APPLICATIONS... 

The molecular orientation on a conventionally extruded PVC pipe, a uniaxially oriented PVC pipe and a biaxially oriented PVC pipe was studied by IR dichroism. The... 

Just as extruded PVC pipe has grabbed a majority share of the water transportation pipe market in the last 50 years... 

Brighton, 23rd-25th April 1996, p.379-90. 42C382 HEAT REVERSION EFFECTS IN EXTRUDED PVC-U PROFILES Haworth B Stephenson R C Loughborough,University European Vinyls Corp.(UK)Ltd. 

Some more recent environmental and political pressures concerning phthal-ates leaching from PVC molded products may provide some newer opportunities for SBC in medical applications. Even though scientific opinion remains mixed as to whether phthalates pose major health concerns, the industry is keenly interested in alternatives. Several manufacturers of health care products have already launched programs aimed at developing alternative materials to eliminate molded and extruded PVC products. 

All the common extrusion techniques can be used to process PVDF into various products, such as rod, sheet, film, pipe, tubing, monofilament, wire insulation, etc.f No extrusion additives, lubricants, or heat stabilizers are needed. Equipment with materials of construction similar to those used for extruding PVC and polyolefins is applicable for PVDF. Extrusion temperatures vary from 210°C to 270°C depending on the type of PVDF resin and the shape being extruded. Extruders with L/D ratios of at least 20 are recommended. For very thin products, the temperature at the dietip can be as high as 320° C as required for heat polishing. 

Activation spectrum for yellowing of the same PVC compositions on exposure to a filtered xenon source, determined by the cut-on filter technique, has also been reported. The wavelength interval % = 310-325 nm was identified as being the most effective in bringing about photoyellowing [37] of extruded PVC sheets with no titania and with 2.5 phr of titania. These findings are consistent with the conclusions from an earlier report of an activation spectrum derived from a monochromatic exposure experiment. For a similar source, the maximum degradation as detected by UV-visible spectral absorbance was found to be at X. = 320 nm [19]. 

This extrudable PVC has found use as tubing for blood transport and delivery systems, dialysis and enteral feeding systems, oxygen delivery systems, catheters, and drainage systems. Product numbers containing an R are special radiation resistant grades (Tables 4.6, 4.12 and 4.13). 

Antimony trioxide, widely used in PVC formulations, gave a reasonably good fire performance but, as expected, increased the smoke emissions detected. It was not foimd to affect the thermal stability of the rigid PVC, and had no effect on either the colour or impact properties of the extruded PVC. 

Crompton has developed a combined lubricant and heat stabiliser, called Mark 2910, for extruded PVC pipe. The special feature of this liquid product is that profile extruders do not have to buy a separate lubricant such as paraffin wax and add it by a further metered operation. 

C P Hall markets butyl benzyl phthalate as a general-purpose plasticiser under the name Plasthall BBP. It is said to reduce the melt viscosity of calendered or extruded PVC considerably, and it competes with dibutyl phthalate, mainly because it is less volatile and more extraction resistant, although it is not as resistant as the higher molecular weight plasticisers. 

Omnifilm, Extruded PVC film. Huntsman Packaging Corp., Sales... 

It is clear that a non-metallic construction would be favoured. A number of non-metallic contenders existed. GRP was not favoured originally because problems had arisen at an earlier installation in which it was used (but see paragraph 24.3.3 below). Similarly extruded PVC pipe was quickly eliminated. Polypropylene lined GRP was rejected because of uncertainty at the time about its manufacture and performance. This left the polyolefins as the strongest contender, and high-density polyethylene (HOPE) and polypropylene (PP) were compared. HOPE was eventually favoured for the following reasons... 

The automotive industry was dependent on rubber cable insulation throughout its formative years. Cable sheathing with extruded PVC began during the Second World War, focusing on the needs of military aircraft it was therefore some years before the motor industry achieved its present state of dependency on PVC. 

Manufacturer PVC Supplier Extruder PVC pellets ACME Tubes, Inc. ACME Tubes, Inc. 

Over the next two decades extruded PVC with a lacquered, lapped rayon secondary coating for protection against soldering temperatures and for identification was the standard wire insulation. The jumper wire over this period was PVC-coated tinned copper wire with a cellulose lacquered rayon braid secondary coating containing a nonflammability additive. 

Prior to the Second World War, equipment cabling was sheathed with painted wool braid and this continued in the UK into the early 1950s when extruded PVC-coated wires were in use. Subsequently, flexible PVC sheathing was introduced. 

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