Page 23 - C:\Users\Adik\Documents\Flip PDF Professional\Marketer PPT LR\

Limitations: Poor heat resistance, reduced barrier properties and creep compared
to LDPE, Attacked by polar solvents, hydrocarbons, oxidants and strong acids
Applications: EVAs are leading polymers for hot-melt manufacturing fulfilling
various requirements in packaging, bookbinding or label sticking. Widely used for
handle grips, flexible tubing, shock absorber in sports shoes for shoe soles, flexible
packaging, shrink wrap, auto bumper pads, flexible toys, ice cube trays, bicycle
saddles, barrel bungs, railway sleeper pads, baby bottle teats, teethers, refrigerator
door gaskets, sealant layer in multilayer films others. The foam is also commonly
used as padding in equipment for various sports such as ski boots, hockey &
boxing. EVA is used in biomedical engineering applications such as drug delivery
device used within the body. While the EVA is not biodegradable within the body, it
is quite inert and causes little or no reaction following implantation.
11) Ethylene Vinyl Alcohol (EVOH):
EVOH copolymers are highly crystalline, and their properties are highly dependent
on the relative concentration of the co-monomers, ethylene and vinyl alcohol.
Generally speaking, as the ethylene content increases, the gas barrier properties
decreases, the moisture barrier properties improve, and the resins are processed
more easily.
Density 1.1 - 1.2 g/cm 3
Melting Temperature 170 °C - 220°C
Glass transition temperature 15 - 70 °C
Max continuous Service temperature 80 - 100 °C
When melt temperature exceeds 250°C the polymer may decompose.
EVOH is hydrophilic, absorbs significant moisture when exposed to humid
conditions, leading to an increase in its oxygen permeability. Pellets should be dried
at 90-110°C for 2-3 h in such case.
EVOH is typically processed by Extrusion and also blow moulding process.
Properties: Outstanding barrier to gases - oxygen, nitrogen, carbon dioxide and
helium, odours and aromas, good printability & weathering resistance, adhesion
with polyamides. Excellent resistance to greases, chlorinated solvents, esters,
alcohols & hydrocarbons, suitable for transparent applications and FDA compliant.
Limitations: Sensitive to moisture, Moderate heat resistance, attacked by acids
and oxidants, Poor adhesion to most polymers, a tie-layer is generally needed
properties highly depend on ethylene to vinyl alcohol concentrations
Applications: co-extruded or laminated as a thin layer between cardboard, foil or
other plastics, Multilayer rigid and flexible food packaging of sauces, edible oils and
juices for improved shelf life, Tubes for cosmetic, packaging processed meats, bag
in box and cereal. Bottles for pesticides and agrochemicals, in auto-motive fuel
systems to control emissions of hydro-carbons from fuel lines and tanks
POLYVINYL CHLORIDE (PVC):
Also known as 'Vinyl' is one of the most versatile and one of the least expensive
polymer made of 57% chlorine (derived from industrial grade salt) and 43% carbon
(derived predominantly from oil / gas via ethylene). It is less dependent than other
polymers on crude oil or natural gas, which is non-renewable, and hence can be
regarded as a natural resource saving plastic.
DAVE TECHNICAL SERVICES 23