Standard Test Method for Accelerated Aging of Adhesive Joints by the Oxygen-Pressure Method

SIGNIFICANCE AND USE
5.1 This test method is useful to the adhesive manufacturer in research and development or in manufacturing control. The results are also used for specification acceptance or as a guide in adhesive selection.  
5.2 The provisions for testing bonded specimens as well as free films are made for two purposes. First, it is possible for an interaction to occur between oxygen and chemicals or degradation products that may affect the degradation of the bonded joints strength. Second, some increase in strength due to oxidative crosslinking may not be detrimental in a bonded assembly and in fact may be beneficial. Adhesives of this behavior are not satisfactorily tested by a film flexibility test.  
5.3 Some users of this test method will be most interested in the performance of the bonded joint; some will be most interested in the performance of the adhesive. In the latter case, it is important to note that the true variance (error mean square) of the strength of the adhesive may be obscured when the tested control specimens or the tested aged specimens show wood failure.  
5.4 Conflict of Procedure—If the procedures of this test method conflict with those of detailed product specifications or manufacturer's use instructions for a particular material, then use the latter.
SCOPE
1.1 This test method describes how to estimate the relative resistance to deterioration of adhesive films and adhesive-bonded joints placed in a high-pressure oxygen environment. The instructions include both wood-to-wood and wood-to-metal joints as well as free film of adhesive. The effects of chemicals such as fire retardants, preservatives, or wood extractives, can be evaluated by using materials containing these chemicals for adherends.  
1.2 This test method is primarily intended for elastomer-based construction adhesives, but is also applicable to other types of adhesives that may be susceptible to oxygen degradation. This accelerated test does not correlate exactly with the natural aging of the adhesive because of the varied conditions of natural aging and the absence of factors such as moisture and stress. The results of this accelerated test are only comparative and must be evaluated against the performance of bonded joints whose natural and accelerated aging characteristics are known.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM D3632-98(2019) - Standard Test Method for Accelerated Aging of Adhesive Joints by the Oxygen-Pressure Method
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3632 − 98 (Reapproved 2019)
Standard Test Method for
Accelerated Aging of Adhesive Joints by the Oxygen-
Pressure Method
This standard is issued under the fixed designation D3632; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method describes how to estimate the relative
D143 Test Methods for Small Clear Specimens of Timber
resistance to deterioration of adhesive films and adhesive-
D454 Test Method for Rubber Deterioration by Heat andAir
bonded joints placed in a high-pressure oxygen environment.
Pressure
The instructions include both wood-to-wood and wood-to-
D572 Test Method for Rubber—Deterioration by Heat and
metal joints as well as free film of adhesive. The effects of
Oxygen
chemicals such as fire retardants, preservatives, or wood
D573 Test Method for Rubber—Deterioration in an Air
extractives, can be evaluated by using materials containing
Oven
these chemicals for adherends.
D907 Terminology of Adhesives
1.2 This test method is primarily intended for elastomer-
D2339 Test Method for Strength Properties of Adhesives in
based construction adhesives, but is also applicable to other
Two-Ply Wood Construction in Shear by Tension Loading
types of adhesives that may be susceptible to oxygen degrada-
3. Terminology
tion. This accelerated test does not correlate exactly with the
natural aging of the adhesive because of the varied conditions
3.1 Definitions—Many definitions in this test method are
of natural aging and the absence of factors such as moisture
defined in Terminology D907.
and stress. The results of this accelerated test are only
4. Summary of Test Method
comparative and must be evaluated against the performance of
bonded joints whose natural and accelerated aging character-
4.1 This test method entails subjecting specimens with
istics are known.
known physical properties to a controlled aging environment
forspecifictimeperiods,thenobservingthephysicalproperties
1.3 The values stated in SI units are to be regarded as
again and noting any changes. The controlled environment
standard. The values given in parentheses after SI units are
consists of elevated temperature (70°C) (158°F) and oxygen at
provided for information only and are not considered standard.
elevated pressure 2.07 MPa (300 psi).
1.4 This standard does not purport to address all of the
4.2 Three types of test specimens are offered. The party
safety concerns, if any, associated with its use. It is the
requesting the adhesive evaluation will choose the type of
responsibility of the user of this standard to establish appro-
specimen to be used.
priate safety, health, and environmental practices and deter-
Physical Property
Specimen Type Configuration
mine the applicability of regulatory limitations prior to use.
Tested
A wood-to-wood lap shear strength
1.5 This international standard was developed in accor-
B wood-to-metal lap shear strength
dance with internationally recognized principles on standard-
C unsupported film flexibility
ization established in the Decision on Principles for the
4.3 Three different oxygen-pressure aging exposures are
Development of International Standards, Guides and Recom-
offered. Use any exposure with any of the above specimens.
mendations issued by the World Trade Organization Technical
The party requesting the adhesive evaluation will choose the
Barriers to Trade (TBT) Committee.
exposure to which the specimens are subjected.
4.3.1 Constant exposure for 500 h with a single test of the
physical property at the end of 500 h.
This test method is under the jurisdiction of ASTM Committee D14 on
Adhesives and is the direct responsibility of Subcommittee D14.70 on Construction
Adhesives. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2019. Published March 2019. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1977. Last previous edition approved in 2011 as D3632 – 98 (2011). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D3632-98R19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3632 − 98 (2019)
4.3.2 Constant exposure for 1000 h with a single test of the 6.1.1.2 The source of heat is optional, but a location outside
physical property at the end of 1000 h. of the aging chamber itself is required.
4.3.3 Constant exposure for up to 1000 h with a series of 6.1.1.3 The heating medium is optional. Water, air, or other
tests of the physical property after 200, 400, 600, 800, and fluids that will not ignite when oxygen is present may be used.
1000 h. Water has an advantage because it transfers heat rapidly and is
noncombustible. When using air for the heating medium,
5. Significance and Use
thoroughlycirculatetheheatedairbymechanicallyagitatingit,
5.1 This test method is useful to the adhesive manufacturer
and use baffles as needed to prevent local overheating and dead
in research and development or in manufacturing control. The
spots. Do not use oils or other combustible fluids as heating
results are also used for specification acceptance or as a guide
media for this test because they are extremely hazardous when
in adhesive selection.
oxygen is present.
6.1.1.4 Use a thermostat to control automatically the tem-
5.2 The provisions for testing bonded specimens as well as
perature of the heating medium.
free films are made for two purposes. First, it is possible for an
6.1.1.5 Record the temperature automatically throughout
interaction to occur between oxygen and chemicals or degra-
the test period. If the pressure chamber is completely
dation products that may affect the degradation of the bonded
immersed, use the temperature of the heating medium as the
joints strength. Second, some increase in strength due to
temperatureofthepressurechamber.Placethesensingelement
oxidative crosslinking may not be detrimental in a bonded
close to the temperature-measuring device but not touching the
assembly and in fact may be beneficial. Adhesives of this
pressure chamber. If the pressure chamber is not completely
behavior are not satisfactorily tested by a film flexibility test.
immersed in the heating medium, place the sensing element in
5.3 Some users of this test method will be most interested in
a thermometer well that extends into the pressure chamber. Fill
the performance of the bonded joint; some will be most
the thermometer well with enough water to cover the element
interested in the performance of the adhesive. In the latter case,
so that heat will transfer easily. If a comparison has been made
itisimportanttonotethatthetruevariance(errormeansquare)
and it has been confirmed that the temperature of the oxygen
of the strength of the adhesive may be obscured when the
within the chamber is the same as the temperature of the
tested control specimens or the tested aged specimens show
heating medium, it is permissible to take the temperature in the
wood failure.
heating medium instead of in the thermometer well. When
5.4 Conflict of Procedure—If the procedures of this test
using air as the heating medium, check the temperature in
method conflict with those of detailed product specifications or
various parts of the oven to determine that the oven is heating
manufacturer’s use instructions for a particular material, then
evenly. In any case, verify the recorded temperature by
use the latter.
checking with a temperature-indicating device whose sensing
element is directly exposed to the oxygen within the pressure
6. Apparatus
chamber.
6.1 Oxygen-Pressure Vessel—The specifications for the
6.1.1.6 Maintain positive, rapid, and complete circulation of
oxygen-pressure vessel described in 6.1.1.1 through 6.1.1.8 are
the heating medium so as to ensure accurate, uniform heating.
the same as those described in Test Method D572. Adequate
6.1.1.7 The pressure chamber should have a reliable safety
safety provisions are important when heating oxidizable or-
valve or rupture diaphragm set for release at 3.448 MPa (500
ganic materials in oxygen, since the rate of reaction may
psi) pressure.
become very rapid and very high pressures may develop.
6.1.1.8 Do not expose any copper or brass parts to the
Heating these materials is especially dangerous when a large
atmosphere nor use them in the pressure chamber or the tubing
surface area is exposed. If the same equipment is used for the
or valves leading to it.
oxygen-pressure test as for the air-pressure heat test (Test
6.2 Testing Machine for Lap Shear Strength Tests—The
Method D454), be careful and check to see that the thermo-
testing machine specifications described in 6.2.1 are the same
static controls are set properly because the specimens may
as those described in Test Method D2339.
react with oxygen very rapidly at the temperature of the
6.2.1 Use a testing machine capable of maintaining a
air-pressure heat test. Fluids acceptable as heating media for
constant rate of loading of 42 to 74 N/s (600 to 1000 lbf/min)
one test may be hazardous when used for the other test.
or a constant rate of crosshead travel of 0.020 mm/s (0.050
6.1.1 Useonoxygen-pressurechamberconsistingofametal
in./min) 6 25 %. Use a testing machine with suitable grips and
vessel designed to retain an internal atmosphere of oxygen gas
jaws so that the specimen can be gripped tightly and held in
under pressure, with provisions for placing specimens within it
alignment as the load is applied. Fig. 1 shows grips and jaws
and for subjecting the entire chamber to controlled uniform
that have been found satisfactory. Place the testing machine in
temperature. Because of the superior temperature control and
an atmosphere that will not noticeably alter the moisture
heat transfer, a metal vessel completely immersed in a liquid
content of the specimens developed under the conditions
medium is recommended for referee tests. Ensure that the
prescribed in 10.2.
apparatus conforms to the following requirements:
6.1.1.1 The chamber can be any size; however, it must be 6.3 Air Curing and Drying Oven—Except for some
large enough so that the specimens can be hung within it modification, the oven specifications described (in 6.3.1
vertically, without crowding them, letting them touch each through 6.3.9) are the same as those described in Test Method
other, or letting them touch the sides of the chamber. D573.
D3632 − 98 (2019)
adhesive manufacturer or by the party requesting the test,
except that the metal used shall not be reactive as, for example,
magnesium plate.
7.3.1 The mill finish or chemical treatment of the surface
should be the same as the material expected to be bonded in
service with finish or surface treatment to be selected by the
adhesive manufacturer or by the party requesting the test,
except that lubricants or other combustible materials shall be
removed from the surface by solvent cleaning before exposure
in the oxygen-pressure vessel.
8. Sampling
8.1 Sampling Method—When several test specimen panels
are made or films cast and groups of individual specimens are
aged for different time intervals, mix all the specimens in a box
and draw at random from the box for assignment to a given
group.
8.2 Sample Size—Use at least five test specimens to deter-
mine the original physical properties of each sample. Also use
five or more specimens of the same material for each exposure
period of the test. But for purposes of statistical analyses
FIG. 1 Grips and Jaws
described in a later section, the number of specimens in the
control group and in each aged group should be the same. The
6.3.1 Use an oven whose interior size is (minimum) 0.40 m
user may increase the number of specimens in each group in
3 3 3
(1 ft ) to (maximum) 1.33 m (36 ft ) or any equivalent
response to the size of the property change to be detected, the
volume.
degree of confidence desired, and the test result variability.
6.3.2 Suspend the specimens vertically without letting them
This subject is further considered in Annex A1.
touch each other or the sides of the oven.
6.3.3 The temperature variation in various parts of the oven
9. Test Specimens
shall not be allowed to exceed 2°C (4°F).
9.1 Lap-shear test specimens must be made from the same
6.3.4 For the heating medium, use air circulated within the
adherends and adhesive materials that are actually used in
chamber at atmospheric pressure.
service. A tension lap-shear specimen made like the ones in
6.3.5 Anysourceofairmaybeused,ifitislocatedintheair
Fig. 2 and Fig. 3 is recommended. Methods for preparing
supply outside of the chamber itself.
wood-to-wood specimens are similar to those described in Test
6.3.6 Install a thermometer in the upper central portion of
Method D2339 with modifications to accommodate mastic
the chamber, near the center of the specimens, to measure the
consistency adhesives.
actual temperature.
6.3.7 Use a thermostat to control the temperature automati- 9.2 Wood-to-Wood Test Panel Preparation:
cally.
6.3.8 Circulate the heated air throughout the oven by
mechanically agitating it. When using a motor-driven fan, the
air must not come in contact with the fan motor brush
discharge because there is danger of ozone forming.
6.3.9 Use baffles where they are needed to prevent local
overheating and dead spots.
7. Materials
7.1 Adhesive, the adhesive to be tested.
7.2 Wood for wood-to-wood and wood-to-metal specimens,
rotary cut, sliced or sawn and jointed veneers 3.2 to 6.4 mm ( ⁄8
to ⁄4 in.) thick, shall be free of defects such as knots, cracks,
short grain, or any discolorations or soft spots indicative of
Metric Equivalents
decay. The species to be used will be decided by the adhesive
Dimension Tolerance Dimension Tolerance
manufacturer or by the party requesting these tests. Generally
mm in.
a high-density wood such as Douglas-fir, hemlock, southern
A 82.6 ±0.25 3.25 ±0.010
pine, or yellow birch is desirable. B 25.4 ±0.25 1.00 ±0.010
C 3.17 ±0.10 0.125 ±0.004
7.3 Metal for wood-to-metal specimen dimensions be 1.6 to
1 1
3.2 mm ( ⁄16 to ⁄8 in.) thick. The metal will be selected by the FIG. 2 Wood-to-Wood Tension Shear Test Specimen
D3632 − 98 (2019)
9.2.3 Follow the
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