ASTM D2342-68(1972)

Method of Test for Determination of Lot-to-Lot Stabilization Uniformity of Propylene Plastics (Withdrawn 1978)

General Information

• Status: Withdrawn
• Technical Committee: D20 - Plastics

Standards Content (Sample)

AMERICAN NATIONAL ANSI/ASTM D 2342 - 68 (Reapproved 1972)
STANDARD
Standard Test Method for
LOT-TO-LOT STABILIZATION UNIFORMITY
1
OF PROPYLENE PLASTICS
This Standard_ is issued under the_ fixed designation D 2342; the number immediately following the designation indicates
the year of ongtnal adoption or, tn the case of rev1s1on, the year of last revision. A number in parentheses indicates the
year of last reapproval.
I. Scope cally designed for applications in which there
is direct contact of the plastic with copper or
I. I This method covers two procedures for
its alloys.
determining the stability of propylene plastics
3.3 Due to the complexities of polymer
when exposed to air in the molten state for a
oxidative degradation and its retardation and
relatively brief period of time:
their dependence on such factors as tempera­
I. 1.1 Procedure A- without the presence
ture and time, the data obtained by these pro­
of copper.
cedures for materials of various polymer and
1.1.2 Procedure B-with the presence of
stabilization types may not correlate with
copper.
behavior under actual use conditions. There­
NOTE I-The values stated in SI units are to be
fore, these procedures are not recommended
regarded as the standard.
for rating or qualifying such materials in the
absence of other long-term aging information.
2. Summary of Method
4. Apparatus
2.1 Plastic pellets are exposed in aluminum
4.1 Oven-Air-circulating oven capable of
or copper dishes in a circulating-air oven at
maintaining a uniform temperature and an air
185 C for definite time periods. Thermal oxi­
flow of 75 to 140 m/min (approximately 250
dative stability under these conditions is de­
to 450 fp.m) measured at the inlet side. A con­
termined visually by comparing the cooled
venient method of checking uniformity of
disk of heated plastic with a standard or by
oven exposure conditions consists of filling the
measuring any change in its flow rate by
oven shelf to be used with the aluminum
ASTM Method D 1238, Measuring Flow
dishes described in 4.2, after charging each
Rates of Thermoplastics by Extrusion Plas­
with 15 g of a general-purpose (moderately
tometer.'
stabilized) polypropylene. Heat for 16 h at
185 ± 2 C. Remove the dishes, cool, and
3. Significance
examine. The polypropylene in each of the
3.1 These procedures are intended primar­
dishes should be similar in color. Variation in
ily as a means for rapid quality control. They
polypropylene color between dishes indicates
serve to indicate the uniformity of the thermal
nonuniformity of oven temperature or air
oxidative stability of a material as produced
flow, or both; if variation occurs, the oven is
from lot-to-lot in a particular composition by
a single manufacturer.
3.2 The test can detect differences among
. ' This method is under the jurisdiction of ASTM Com­
materials having different levels and types of
mittee D-20 on Plastics and is the direct responsibility Of
Subcommittee D-20.12 on Olefin Plastics.
stabilizers. Procedure A is applicable to all
Current edition effective Jan. 10, 1968. Originally issued
propylene plastics. The use of Procedure B is
19~5. Replaces D 2342 - 65 T.
generally limited to materials that are specifi- Annual Book of ASTM Standards, Part 35.

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D2342
use with materials of widely differing stabilization
unsatisfactory and must not be used.
characteristics. The exposure for a particular prod­
Non 2-A Freas oven, Model 625, gives satis­
uct should be of sufficient duration to detect any
factory results when used with the air intake and
real lot-to-lot abnormality but should not be too
exhaust vents wide open and the air flow dial set at
excessive since inherent variability of the method
the maximum air flow.
increases with the degree of degradation. A recom­
mended technique for determining a suitable expo­
4.2 Dishes-Aluminum dishes and copper
sure time for control purposes with a given product
dishes, each approximately 0.14 mm (0.0055
is as follows: Make flow rate determinations on a
representative number of replicate samples after
in.) thick, 70 mm (2.76 in.) in diameter, and
several intervals of exposure to establish the longest
17 mm (0.67 in.) deep.
time of exposure that still gives significantly repro­
Non 3-Satisfactory aluminum dishes are flat ducible results. For example, I, 2, 4, 8, and 16 h
may be tried for each particular resin. If the repro­
bottom aluminum foil dishes used for milk analysis,
ducibilities of replicate determinations for the 8 and
made from aluminum alloy I 145-O. At present
there is no commercial source for similar copper 16-h intervals are poor and those for the I, 2, and 4-
h exposures are acceptable and of the same order of
dishes, but for the purpose of this test these may be
magnitude, a 4-h exposure time might be specified.
easily fabricated by hand or stamping-tool from
annealed ETP
...