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RESIN MATERIALS
This section provides a brief description of common plastic container
resin materials, their qualities, usages and limitations.
High
Density Polyethylene (HDPE)
HDPE is the most widely used resin for plastic bottles. This material
is economical, impact resistant, and provides a good moisture barrier.
HDPE is compatible with a wide range of products including acids and caustics
but is not compatible with solvents. It is supplied in FDA approved food
grade.
HDPE is naturally translucent and flexible. The addition of color will
make HDPE opaque although not glossy.
HDPE lends itself readily to silk screen decoration. While HDPE provides
good protection at below freezing temperatures, it cannot be used with
products filled at over 160° F or products requiring a hermetic (vacuum)
seal.
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
PET
Polyethylene Terephthalate is commonly used for carbonated beverage bottles.
PET provides very good alcohol and essential oil barrier properties, generally
good chemical resistance (although acetones and ketones will attack PET)
and a high degree of impact resistance and tensile strength. The orienting
process serves to improve gas and moisture barrier properties and impact
strenght.
This material does not provide resistance to high temperature applications
-- max. temp. 160° F.
Polyvinyl
Chloride (PVC)
PVC is naturally clear, has extremely good resistance to oils, and has
very low oxygen transmission. It provides an excellent barrier to most
gases and its drop impact resistance is also very good. This material
is chemically resistant, but it is vulnerable to solvents.
PVC is an excellent choice for salad oil, mineral oil, and vinegar. It
is also commonly used for shampoos and cosmetic products. PVC exhibits
poor resistance to high temperatures and will distort at 160° F, making
it incompatible with hot filled products
Polypropylene
(PP)
Polypropylene is used primarily for jars and closures and provides a rigid
package with excellent moisture barrier.
One major advantage of polypropylene is its stability at high temperatures,
up to 200° F. Polypropylene is autoclavable and offers the potential
for steam sterilization. The compatibility of PP with high filling temperatures
is responsible for its use with hot fill products such as pancake syrup.
PP has excellent chemical resistance, but provides poor impact resistance
in cold temperatures
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.
Flourine
Treated HDPE:
Bottles
produced with a mixture of flourine gas and air, or exposed to flourine
gas in a secondary operation, are similar in appearance to HDPE and have
exceptional barrier properties to hydrocarbons and aromatic solvents.
Flourine treated hdpe bottles also resist penetration by oxygen and carbon
dioxide.
Flourine
treated bottles are excellent for use with insecticides, photographic
chemicals, agricultural chemicals, household cleaners, waxes, paint thinner
and gasoline.
| Comparison of Bottle Polymer
Materials |
| Material |
Clarity |
O2 |
CO2 |
Flexural
Modulus
x 103 |
Impact
Strength |
Maximum
Hot Fill
(Fo) |
Minimum
Tolerance
(Brittleness)
Co |
Density
g/cc |
| LDPE |
P |
9,500 |
42,000 |
50 |
G |
150o |
-100o |
0.92 |
| HDPE |
P |
4,000 |
18,000 |
150 |
G |
190o |
-100o |
0.96 |
| PP |
P |
3,500 |
7,000 |
200 |
F |
200o |
0o |
0.91 |
| PS(Styrene) |
E |
5,000 |
16,700 |
400 |
P |
150o |
|
1.05 |
| PVC |
G |
150 |
380 |
300 |
F |
140o |
30o |
1.35 |
| PC |
E |
4,500 |
8,225 |
350 |
E |
240o |
-125o |
1.20 |
Unoriented
Pet |
E |
100 |
720 |
300 |
F |
140o |
|
1.33 |
Oriented
Pet |
E |
75 |
540 |
450 |
G |
120o |
-40o |
1.36 |
| PETG |
E |
400 |
1,200 |
300 |
G |
140o |
-40o |
1.27 |
| K-Resin |
E |
250 |
|
205 |
G |
|
|
1.01 |
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