ASTM D2115-92(2003)
(Practice)Standard Practice for Oven Heat Stability of Poly(Vinyl Chloride) Compositions
Standard Practice for Oven Heat Stability of Poly(Vinyl Chloride) Compositions
SCOPE
1.1 This practice lists procedures for determining the relative thermal stability of sheet or molded poly(vinyl chloride) compounds as indicated by discoloration due to exposure to an elevated temperature at controlled oven conditions.
1.2 A specimen preparation technique using a two-roll mill is provided for compositions that are not in molded or sheeted form.
1.3 This practice is not intended for use in purchasing specifications because the conditions of processing plastic compounds vary widely, and the degree of correlation of data obtained by this practice to process exposure has not been determined. However, despite this limitation, this practice does yield data of value in judging the comparative service quality of poly(vinyl chloride) compositions.
1.4 The values stated in SI units are to be regarded as the standard. The values in brackets are given for information only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Note 1—This standard is similar in content, but not technically equivalent to ISO 305-1990.
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Designation: D 2115 – 92 (Reapproved 2003)
Standard Practice for
Oven Heat Stability of Poly(Vinyl Chloride) Compositions
This standard is issued under the fixed designation D 2115; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Discoloration Method
1.1 This practice lists procedures for determining the rela-
3. Terminology
tive thermal stability of sheet or molded poly(vinyl chloride)
3.1 General—Definitions are in accordance with Terminol-
compounds as indicated by discoloration due to exposure to an
ogy D 883 and abbreviations with Terminology D 1600, unless
elevated temperature at controlled oven conditions.
otherwise indicated.
1.2 A specimen preparation technique using a two-roll mill
is provided for compositions that are not in molded or sheeted
4. Significance and Use
form.
4.1 Poly(vinyl chloride) compositions degrade by discolora-
1.3 This practice is not intended for use in purchasing
tion on prolonged exposure to heat. The degree of discoloration
specifications because the conditions of processing plastic
is related to the condition of exposure, such as length of period
compounds vary widely, and the degree of correlation of data
and temperature. When the conditions of exposure are fixed
obtained by this practice to process exposure has not been
and controlled, then the relative resistance to discoloration due
determined. However, despite this limitation, this practice does
to heat of two or more compositions may be determined. The
yield data of value in judging the comparative service quality
precision of heat stability testing is also dependent on the
of poly(vinyl chloride) compositions.
thickness of the specimens and the history of heat exposure
1.4 The values stated in SI units are to be regarded as the
prior to testing. This practice allows for control or the reporting
standard. The values in brackets are given for information only.
of these variables.
1.5 This standard does not purport to address all of the
4.2 This practice is particularly applicable for determining
safety concerns, if any, associated with its use. It is the
gross differences in the heat stabilities of poly(vinyl chloride)
responsibility of the user of this standard to establish appro-
compositions that are detectable as a color change. It is not
priate safety and health practices and determine the applica-
intended to measure absolute thermal stability. Although the
bility of regulatory limitations prior to use.
observed color changes may be evidence of degradation,
NOTE 1—This standard is similar in content, but not technically
molecular degradation phenomena such as chain-scission or
equivalent to ISO 305–1990.
cross-linking may not be identifiable.
2. Referenced Documents
NOTE 2—While discoloration caused by exposure to elevated tempera-
ture is commonly regarded as evidence of degradation in poly(vinyl
2.1 ASTM Standards:
chloride) compositions, it must be borne in mind that some vinyl
D 883 Terminology Relating to Plastics
compositions may undergo substantial change in color without appre-
D 1600 Terminology for Abbreviated Terms Relating to
ciable loss of mechanical strength, chemical resistance, etc., whereas
Plastics
others may resist change in color yet undergo substantial change in other
2.2 ISO Standard:
properties. Therefore, resistance to discoloration should not be taken as
ISO305–1990 Plastics—Determination of Thermal Stability sole evidence of thermal stability. It is recommended that this test be
supplemented by others such as tensile strength and elongation, impact
of Poly(Vinyl Chloride), Related Chlorine-Containing
strength, and deflection temperature under load (for rigid compositions),
Polymers and Copolymers and Their Compounds—
Durometer hardness (for nonrigid compositions), and dilute solution
viscosity, and that the test results before and after oven exposure be
compared to determine the degree of degradation which has been
This practice is under the jurisdiction of ASTM Committee D20 on Plastics and
produced in each of the properties measured.
is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials
(Section D20.15.07).
Current edition approved July 10, 2003. Published September 2003. Originally
approved in 1962. Last previous edition approved in 1997 as D 2115 – 92(97).
2 Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
Annual Book of ASTM Standards, Vol 08.01.
4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 2115 – 92 (2003)
NOTE 5—If the sample has been precompounded, omit 6.1.2 and 6.1.3.
4.3 This practice may be used to predict the relative
Specimens in sheeted form shall be cut to size according to 6.1.5.
discoloration in processing, provided that the compositions in
question are tested at the relative maximum temperatures
6.1.1 The batch size shall be such that a rolling bank 6.35 to
1 1
developed in processing.
12.7 mm [ ⁄4 to ⁄2 in.] in diameter is obtained across the face
4.4 This practice is not applicable to materials that will
of the mill with the rolls set to give a sheet 0.816 6 0.08 mm
cross-contaminate during oven exposure.
[0.040 6 0.004 in.] thick.
NOTE 6—Other specimen thicknesses may be used. However, heat
5. Apparatus
stability is affected by thickness, and all comparative tests shall be made
5.1 Mill—A two-roll laboratory plastic or rubber mill (for on specimens of the same nominal thickness.
use for preparing specimens from the basic ingredients or from
6.1.2 Weigh all components to an accuracy of 6 1% of
molding or other compounds). Provision shall be made for
their nominal weight.
heating the rolls to the desired temperature and for maintaining
6.1.3 Premix the solid and liquid components separately in
this temperature constant over the surfaces of both rolls within
suitable containers until homogeneous in appearance. Add dry
63°C.
components to the container holding the liquid components,
5.2 Oven—The oven shall be of the forced-air type and shall
then blend together until homogeneous.
have the following additional requirements:
6.1.4 Charge the batch or composition to the mill rolls
5.2.1 The oven temperature s
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