Polyethylene
Terephthalate (PET)
PET is one of several resins in the polyester family. The major raw
materials used to manufacture PET bottles include ethylene glycol,
terephthalic acid or dimethyl terephthalate and small quantities of
additives such as catalyst and stabalizers. Bottles made from PET are
injection blow moldsed, unoriented or injection stretch blow moldsed,
biaxially oriented. PET bottles have outstanding clarity, good impact
and scratch resistance, high gloss finish and good barrier properties.
They are lightweight and safe compared to glass (no breakage on filling
lines, in transit, retail stores and in homes). Containers manufactured
with PET resin are ideal for packaging a wide range of food product,
toiletries, cosmetics and household and pharmaceutical products. Each
application should be tested to ensure that the product is compatible
with the container.
High
Density Polyethylene (HDPE)
HDPE is the most widely used resin for plastic bottles. This
material is economical, impact resistant, compatible with a wide range
of products (including acids and caustics) and provides a good moisture
barrier. It is usually supplied in FDA approved food grade. When
fluorine treated, HDPE becomes an effective package for solvents
(aromatic hydrocarbins) and oxygen sensitive extracts. HDPE is naturally
translucent and flexible. The addition of color will make HDPE opaque
although not glossy. Adding extra weight to the bottle will yield a
rigid container. HDPE is supplied surface-treated on a stock basis and
lends itself readily to silkscreen decoration. While HDPE provides very
good protection at temperatures below freezing, it cannot be used with
products filled at over 180?F or products requiring a hermetic seal.
Vinyl
/ Polyvinyl Chloride (PVC)
PVC is naturally clear, has extremely good resistance to oils and
very low oxygen transmission. It provides an excellent barrier to most
gases, but is vulnerable to solvents. PVC is a semi-rigid material
which, when produced on extrusion blow-molding equipment, can
accommodate handled designs. Improvements in resin formulation have
increased oxygen barrier properties and chemical resistance, with a
20-30% improvement in drop impact resistance. PVC exhibits low
temperature resistance and will distort at 160?F. It is not compatible
with hot filled products. Because it provides a good oxygen barrier, PVC
is an excellent choice for salad oil, mineral oil, and vinegar. It is
also commonly used for shampoos and cosmetic products.
Low
Density Polyethylene (LDPE)
LDPE is similar to HDPE in composition. It is less rigid and
generally less chemically resistant than HDPE, but is more translucent.
LDPE is used primarily for squeeze applications. LDPE is significantly
more expensive than HDPE, but will yield a glossy bottle when produced
in colors.
Polypropylene
(PP)
Polypropylene is a naturally translucent material which provides
contact clarity and an excellent moisture barrier. One major advantage
of polypropylene is its stability at high temperatures (maximum
temperature = 230-260F); it is autoclavable and offers the potential for
steam sterilization. PP's compatibility with high filling temperatures
is responsible for its use with hot fill products such as pancake syrup.
PP has an excellent chemical resistance, but provides poor impact
resistance in sub-freezing temperatures. Produced in color, PP exhibits
a glossy finish.
Polystyrene
(PS)
Styrene offers excellent clarity and stiffness at an economical
cost. It is commonly used with dry products including vitamins,
petroleum jellies and spices. Styrene does not provide good barrier
properties and exhibits poor impact resistance. It can be screen printed
without being flame treated and lends itself well to offset printing.
Other
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