Polyethylene Foam Resins

PE foams exhibit a superior ability to absorb mechanical impact, reduced hygroscopicity, low permeability to water vapours, and good resistance to weathering and chemicals compared to polystyrene (PS) and polyurethane (PU) foams. They are rigid or flexible foams depending on the volume increase which may be anything from three to five to as much as 40 times the initial volume. 

In practice the ultimate growth potential for PE foam versus PS and PU foams is limited by the basic characteristics of PE. They have low glass transition temperatures (T ) and the flexural modulus range is limited compared with PU foams. The introduction of SSC PE has increased the potential flexural modulus range. 

PE foams have excellent barrier properties, are thermoformable, have excellent chemical resistance, and are available in fire-retarding forms however, they are more expensive than PS 

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Brookfield, Ct., 2002, Session IV, p. 103-12, 27cm, 012 POLYETHYLENE FOAM RESIN OUTLOOK Harden W... 

Polyethylene. There are three basic types of polyethylene loams of importance (I) extruded loams from low density polyethylene ILDPE) f2) foam products from high density polyethylene (HDPE) and ( ) cross-linked polyethylene foams. Other polyolehn foams have an insignificant volume as compared to polyethylene foams and most or their uses are as resin extenders. 

Ease of fabrication is one of the many advantages of polyethylene foam. It can be skived to precise thickness, cut and shaped to form custom parts, and joined to itself or to other materials without major investment in complex equipment. It can also be vacuum formed. Expanded polyethylene will adhere to itself by the use of heat alone. Hot air, or a plate heated to approximately 350°F (177°C) can be used to simultaneously heat the surfaces of two sections of foam to be joined. Upon softening, the two pieces are quickly joined together under moderate pressure, and an excellent bond formed, with only a short cooling period required. Release of the melted foam is aided by a coating of fluorocarbon resin or silicone dispersion on the heating surface. The foam may also be bonded to itself and to other materials by the use of solvents or commercially available adhesives (6). 

High-Density Polyethylene Foams These foams are defined by the specific gravity (ca. 0.96 g/cc) and melt index of the basic resin. They have been used extensively in the U.S. and Europe, particularly for materials-handling applications, such as boxes, crates, and pallets because, imtil recently, they were much cheaper than polypropylene (13). 

ArceL [Arco] Polyethylene copolymers resins fa molded resilient foam pkg. 

Uses Detergent, oil emulsifier, thickener, wetting agent, defoamer, dispersant, solubilizer, stabilizer for cosmetics, pharmaceuticals, metal cleaning, emulsion polymerization antistat for polyethylene and resin molding powds. demulsifier in petrol, industry surfactant in latex-based paints, aq.-based syn. cutting fluids and vulcanization of rubber Features Low foaming... 

Flexible plastic foams may be found in the form of very soft cushioning materials used in upholstery, clothing interlayers, automobile seats, vibration absorbers, etc. The most common flexible foam resins are polyurethanes, foamed vinyls, cellular polyethylene, cross-linked polyethylene, and silicone foam. Semirigid foams are used for floatation devices, marine bumpers, special electrical insulation on television cables, packaging, and a host of other applications. Rigid foams are used in the production of airplane parts, boats, electronic encapsulation, and many furniture applications where wood was formerly used. 

Gas-filled plastics are polymer materials — disperse systems of the solid-gas type. They are usually divided into foam plastics (which contain mostly closed pores and cells) and porous plastics (which contain mostly open communicating pores). Depending on elasticity, gas-filled plastics are conventionally classified into rigid, semi-rigid, and elastic, categories. In principle, they can be synthesized on the basis of any polymer the most widely used materials are polystyrene, polyvinyl chloride, polyurethanes, polyethylene, polyepoxides, phenol- and carbamideformaldehyde resins, and, of course, certain organosilicon polymers. 

Various polymeric materials were tested statically with both gaseous and liquefied mixtures of fluorine and oxygen containing from 50 to 100% of the former. The materials which burned or reacted violently were phenol-formaldehyde resins (Bakelite) polyacrylonitrile-butadiene (Buna N) polyamides (Nylon) polychloroprene (Neoprene) polyethylene polytriflu-oropropylmethylsiloxane (LS63) polyvinyl chloride-vinyl acetate (Tygan) polyvinylidene fluoride-hexafluoropropylene (Viton) polyurethane foam. Under dynamic conditions of flow and pressure, the more resistant materials which binned were chlorinated polyethylenes, polymethyl methacrylate (Perspex) polytetraflu-oroethylene (Teflon). 

A polymeric composition for use in foam manufacture comprises a linear low density polyethylene and a resiliency modifier resin. The linear low density polyethylene is present in an amount of from about 1 to 90 weight percent of the polymeric composition and has a z-average molecular weight greater than about 700,000. The resiliency modifier resin is present in an amount of from 10 to about 99 weight percent of the polymeric composition and may be a low density polyethylene. 

Describes open cell foamed articles including silane-grafted single-site initiated polyolefin resins. The olefin polymer resin can be a polyethylene, a copolymer of ethylene, a C3-C20 alpha-olefin, or a copolymer of ethylene, a C3-20 alpha-olefin and a C4-C20 diene. The open cell foamed articles have good cushioning properties and can be non-allergenic. 

Mainz, Germany, 4th-5th Nov.1997, p.65-85. 6124 LABORATORY EVALUATION OF METALLOCENE RESINS IN CROSSLINKED POLYETHYLENE (XLPE) FOAM HeckRL... 

This patent is a reissue (RE 34607). The composition described, capable of forming foams with excellent mechanical properties and heat resistance, is made of (a) 14-80 wt.% of a propylene-ethylene random copolymer having an ethylene content of 1.5-6 wt.%, (b) 10-60 wt.% of a propylene-ethylene random copolymer having an ethylene content of 0.2-1.0 wt.%, (c) 10-60 wt.% of a linear low-density polyethylene, and (d) 1-30 pbw, per 100 pbw of the above resin composition, of a foaming agent. JAPAN... 

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