Polycarbonate blow molding

Other polymers that we blow mold include polyvinyl chloride and polycarbonate. We use the former to make cooking oil and household cleaning product bottles. The latter is used to make the large water bottles that we see in water coolers. 

We routinely manufacture polycarbonate products by injection molding, blow molding, extrusion, and thermoforming. Injection molding is the most common processing technique. 

Engineers like to design machines that take plastics and inject them into molds, extrude them into filament, sheets, rods, and film, or blow-mold them into shapes. They want these plastics to have a terrific balance of mechanical, electrical, and chemical properties. That s why they have attached their name to engineering resins, a set of plastics unlike thermosets that they can remelt and further process mechanically. Nylon, polycarbonates, and polyesters are the three most popular engineering resins. 

Injection blow molding of polycarbonates produces an assortment of containers from 20-L water bottles and 0.25-L milk bottles to outdoor lighting protective globes. 

Parison (preform) for blow molding, 162, 162-163,260 Parkes, Alexander, 53, 150 Patrick, J. C., 64 PC. See Polycarbonate PDMS (poly[dimethyl-siloxane]), 135-136, 138,155 Pectin, 122,130... 

Merlon [Bayer], TM for a polycarbonate resin. Rods, tubes, pipes, sheets, film extrusions, and special types may be produced by extrusion, thermoforming, injection, and blow moldings. 

Recent advances in polycarbonates include further enhancement of normally good fire resistance color elimination (an improvement approaching glass) and development of scratch-resistant coatings for glazing applications branched material for blow-molding bottles optimization of structural foam molding and compounds selective copolymerization and development of many different commercial polyblends. 

Lexan . [GE Plastics GE Plastics Ltd.] Polycarbonate resin thermoplastic resin with high impact strei th, close molding tolerances, low mold shrinkage, dimensional stability, weatherabil-ity and corrosion resistance, uv stability for inj. and blow molding, extrusion, film, and foam q lics. 

In blow molding, a tube of molten plastic material, the parison, is extruded over an apparatus called the blow pipe and is then encased in a split mold. Air is injected into this hot section of extruded stock through the blow pipe. The stock is then blown outward, where it foUows the contour of the mold. The part is then cooled, the mold opened, and the molded part ejected. In very heavy sections, carbon dioxide or Uquid nitrogen may be used to hasten the cooling. This process is widely used in molding high- and low-density polyethylene, nylon, polyvinyl chloride (PVC), polypropylene, polystyrene, and polycarbonates. 

A newer development in this area is the production of retortable, multilayer, blow-molded containers that incorporate polycarbonate as the tough outer layer, with EVOH or poly(vinyiidene chloride) (PVDC) as the barrier, and polypropylene (PP) as the food contact layer. The advantages of polycarbonate are its light weight, improved heat stability, and good optics compared to the polyolefins that are normally used. 

Coextrusion to form an effective barrier layer has been used by Plysu Containers Limited and Reed Plastic Containers, both producing tough solvent-resistant containers. The five-layer construction used by Plysu has HDPE both on the inside and outside, and a central barrier layer with adhesive layers on either side to allow lamination to HDPE. The Reedpac range of blow-molded containers developed by Reed Plastic Containers have polyethylene, polypropylene, polycarbonate, or PET combined with barrier resins such as polyamide, PVDC, and EVOH polymer. 

General Electric produces several blow molding grades of polycarbonate for the vertical panels of ovens and dishwashers. Advantages of polycarbonate panels over metallic panels include low cost product, rigidity, and dimensional stability. 

Polycarbonate Polyester Alloys High-performance flier-moplastics processed by injection and blow-molding. Used in auto parts. 

Phenoxy is amorphous and transparent. It resembles, both in stmcture and properties, polycarbonate, except for the existence of the fimctional and reactive radical, OH, which may also react with di-isocyanate. Phenoxy excels in low permeability to oxygen and dimensional stability, however, it softens at 85 C. It may also crack under load, and absorb water. On the other hand, it is rigid and tough, easily processed via extrusion, injection, and blow molding at moderate temperature (200 C-270 C). Phenoxy is used in coatings and glues, as well as in some engineering applications, in spite of competition with polycarbonate. 

Blow molding ABS, acrylic, cellulosics, nylon, polycarbonate, polyester (thermoplastic), polyethylene, polypropylene, polystyrene, polysulfone, PVC, SAN... 

ASA resins are available for blow molding, extrusion, and injection molding. ASA resins are also blended with polycarbonate, polyvinyl chloride, and acrylonitrile ethylene styrene for specific property enhancements. The main suppliers are BASF (Luran and Centrex), BP Chemicals (Barex), Bayer (Centrex), LG Chemical (LI and LE polymers), and GE (Geloy). 

Applicable materials for the injection blow molding process include high-density polyethylene (HOPE), low-density polyethylene (LDPE), polystyrene (PS), styrene acrylonitrile (SAN), ethylene vinyl acetate (EVA), polypropylene (PP), polycarbonate (PC), and polyurethane (PU). Polyethylene terephthalate (PET) and polyacrylonitrile (PAN) are less commonly used in the injection blow molding processes. 

This copolymer is also widely used as a blending compound with olefin homopolymers as well as with polyamides, polyesters, and polycarbonate to improve impact strength and toughness and either to increase heat seal response or to promote adhesion. EMA is also used in soft blow-molded articles such as squeeze toys, tubing, disposable medical gloves, and foamed sheet. EMA copolymers and ethylene ethyl acrylate (EEA) copolymer containing up to 8% ethyl acrylate are approved by the FDA for food packaging. 

Polycarbonate is available in blow molding, extrusion, and injection molding grades. Major suppliers include GE Plastics (Lexan), Bayer (Apec, Makrolon), Ashley Polymers (Ashiene), Mitusbishi Gas (lupilon), Dow Chemical (Calibre), Bay Resins, ComAlloy, DSM Engineering, LNP (Lubricomp), Nova Polymers, Federal Plastics, Ferro (Karlex), and Compound Technologies. 

These linear polymers, in various molecular weights and with various monofunctional phenol end groups, dominate commercial polycarbonate production and sales. However, these products do not meet all requirements, particularly for extrusion and extrusion blow-molding applications where there is a need for polycarbonates that provide nonnewtonian, shear-dependent, viscoelastic flow properties. These desirable flow... 

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