ASTM D7487-08
(Practice)Standard Practice for Polyurethane Raw Materials: Polyurethane Foam Cup Test
Standard Practice for Polyurethane Raw Materials: Polyurethane Foam Cup Test
SIGNIFICANCE AND USE
General Utility:
It is useful to verify catalyst levels in a resin blend or a polyurethane system.
This practice is suitable for research, quality control, specification testing, and process control.
Limitations:
Several of the measured parameters are subjective. Therefore, operator-to-operator variability and lab-to-lab variability can be much higher than that of a single operator.
The variability of this practice is dependent on the consistency of mixing of the reactants.
The estimation of precision in this practice is based on typical formulations for rigid and flexible foams. Formulations with faster reaction times will likely have greater variability, particularly cream time (initiation time). Formulations with slower reaction times will likely have greater variability in the measurement of free rise time.
It is possible that low-level (ppm, ppb) ingredient contamination will not be detectable using this practice. Confirmation of such contamination will potentially require large-scale (~ 20 litres) tests and is out of the scope of this practice.
SCOPE
1.1 This practice covers the determination of cream time (initiation time), top of cup time, free rise time, free rise height, string gel time (pull time), tack free time, settle back, and free rise density of polyurethane foam formulations using a cup foam test.
1.2 Typical definitions, terms, and techniques are described; including procedures for mixing and transferring samples to the foaming container; and data gathering and evaluation. However, agreement between the customer and the testing laboratory for all these items must be obtained prior to use.
1.3 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—There is no known ISO equivalent to this standard.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7487 − 08
StandardPractice for
Polyurethane Raw Materials: Polyurethane Foam Cup Test
This standard is issued under the fixed designation D7487; 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 3.2.3 free rise time (end of rise time)—the time at which the
foam stops expanding as observed visually.
1.1 This practice covers the determination of cream time
3.2.4 string gel time (pull time)—time at which long
(initiationtime),topofcuptime,freerisetime,freeriseheight,
“strings”oftackymaterialcanbepulledawayfromthesurface
string gel time (pull time), tack free time, settle back, and free
ofthefoamwhenthesurfaceistouchedbytheedgeofatongue
rise density of polyurethane foam formulations using a cup
depressor or similar implement.
foam test.
3.2.5 tack free time—the time at which the surface of the
1.2 Typical definitions, terms, and techniques are described;
foam can be touched with a gloved finger or tongue depressor
including procedures for mixing and transferring samples to
without sticking.
the foaming container; and data gathering and evaluation.
However, agreement between the customer and the testing
3.2.6 free rise density—the density in kg/m of a polyure-
laboratory for all these items must be obtained prior to use.
thane foam prepared in an open cup.
1.3 This standard does not purport to address all of the
3.2.7 free rise height—height of the foam at free rise time
safety concerns, if any, associated with its use. It is the
3.2.8 final height—height of foam after specified time
responsibility of the user of this standard to establish appro-
3.2.9 % settle back (% recession, % sigh back, or % sink
priate safety and health practices and determine the applica-
back)—percentagedecreasefromfreeriseheighttofinalheight
bility of regulatory limitations prior to use.
3.2.10 resinblend(formulatedpolyol)—completeingredient
NOTE 1—There is no known ISO equivalent to this standard.
formulation without the isocyanate
2. Referenced Documents
4. Summary of Practice
2.1 ASTM Standards:
4.1 Specific events (cream time, initiation time, top of cup
D883 Terminology Relating to Plastics
time, free rise time, free rise height, string gel time, and tack
E691 Practice for Conducting an Interlaboratory Study to
free time) from a polyurethane foamed in a cup are measured
Determine the Precision of a Test Method
to verify the resin blend composition or levels of ingredients in
formulations used to make polyurethane foams.
3. Terminology
4.2 An estimation of the method precision is given. An
3.1 Definitions—Terminology used in this practice follows
estimation of bias is not given because there is no suitable
that defined in Terminology D883.
reference method.
3.2 Definitions of Terms Specific to This Standard:
5. Significance and Use
3.2.1 cream time (initiation time)—the time between the
start of mixing and the point at which fine bubbles begin to 5.1 General Utility:
appear. 5.1.1 It is useful to verify catalyst levels in a resin blend or
a polyurethane system.
3.2.2 top of cup time—the time at which the crown of the
5.1.2 This practice is suitable for research, quality control,
rising foam reaches the plane of the top of the cup.
specification testing, and process control.
5.2 Limitations:
ThispracticeisunderthejurisdictionofASTMCommitteeD20onPlasticsand
5.2.1 Several of the measured parameters are subjective.
is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics
Therefore, operator-to-operator variability and lab-to-lab vari-
and Elastomers.
ability can be much higher than that of a single operator.
Current edition approved Nov. 15, 2008. Published November 2008. DOI:
10.1520/D7487-08.
5.2.2 The variability of this practice is dependent on the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
consistency of mixing of the reactants.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2.3 The estimation of precision in this practice is based on
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. typical formulations for rigid and flexible foams. Formulations
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7487 − 08
NOTE 3—This cup is then nested into another cup to prevent spilling
with faster reaction times will likely have greater variability,
chemicals in case the propeller cuts the first cup. Some practitioners use
particularly cream time (initiation time). Formulations with
plastic cups with thicker walls and omit the second cup.
slower reaction times will likely have greater variability in the
NOTE 4—If users elect to mix in one cup and pour into a second cup,
measurement of free rise time.
results may vary.
5.2.4 It is possible that low-level (ppm, ppb) ingredient
8.4 Immerse the stirrer blade completely to a starting
contamination will not be detectable using this practice.
position in contact with the bottom of the cup and retract it
Confirmation of such contamination will potentially require
slightly.
large-scale (~ 20 litres) tests and is out of the scope of this
8.5 Simultaneously, turn on the mixer switch, and start the
practice.
stopwatch.
6. Apparatus
NOTE 5—In some cases, it is better to ramp up the mixer speed. Such
6.1 Stirrer for Mixing:
modifications need to be established prior to testing.
6.1.1 Stirring motor,
8.6 Mix the materials for a specified time then, remove the
6.1.2 Propeller or other type of mixing apparatus, and
cup from the spinning mixing blade.
6.1.3 Stainless steel shaft.
NOTE6—Caremustbetakentoremovethecupslowlysothatsplashing
6.2 Cups
ofthereactionmixturedoesnotoccur.Ifappropriate,stopthemixeratthe
end of the specified time and then remove the cup.
6.3 Knife—Cuttinglengthoftheblademustbelargeenough
8.7 Place the cup in a fume hood and record the times as
to cleanly cut through the risen foam at the top of the cup.
defined in Section 3.
6.4 Thermometers—accurate to 60.5°C.
8.8 Clean the stirrer blade thoroughly after each test.
6.5 Stopwatch—capable of measuring to 0.1 s.
8.9 After a specified time, cut off the crown of the foam as
6.6 Balance—capacity of 100 g and capable of weighing to
close to the top edge of the paper cup as possible.
0.1 g.
8.10 Record the weight of the cup plus remaining foam to
6.7 Tachometer—capable of measuring to the nearest rpm.
the nearest 0.1 g.
6.8 Ruler—capable of measuring to 1 mm.
9. Calculation
7. Test Conditions
9.1 Calculate the Free Rise Density and express as kg/m .
7.1 Since isocyanates react with moisture, keep laboratory
9.1.1 An example of how Free Rise Density can be deter-
humidity low, preferably around 50 % relative humidity.
mined is as follows:
7.2 Some of the parameters are influenced by atmospheric
9.1.1.1 Calculate the weight of the foam in the cup as
pressure. The quantitative influence is not known at this time.
follows:
If results are to be compared between laboratories located at
W 5 W 2 W
@ #
~foam! ~cup1cut foam! ~empty cup!
significantly different elevations above sea level, it is advisable
to measure the barometric pressure and develop a suitable,
where:
empirical correction factor. (Warning—Many diisocyanates
W = weight in grams of the remaining foam in
(foam)
are known or suspected sensitizers. Over-exposure to diisocya-
the cup
nates can lead to adverse health effects which may include the
W = weight in grams of the cup plus remaining
(cup + cut foam)
development of occupational asthma and other respiratory,
foam
skin, and eye effects. Engineering controls, or personal protec- W = weight in grams of the empty cup
(empty cup)
tive equipment, or both, including respiratory, skin, and eye
9.1.1.2 Calculate the Free Rise Density as follows:
protection, are to be used when there is a potential for
Free Rise Density kg/m 5 g/L 5 W /V
~ !
foam cup
over-exposure to diisocyanates. The product suppliers’ Mate- ~ ! ~ !
rial Data Safety Sheet (MSDS) provides more detailed infor-
where:
mation about potential adverse health effects and other impor-
W = weight in grams of the remaining foam in the cup
(foam)
tant safety and handling information. Always follow the
V = the volume of the cup in litres
(cup)
specific instructions provided on the MSDS.)
9.1.2 An example of how to calculate % Settle Back as
8. Procedure
follows:
8.1 Check the stirrer speed with a tachometer and rotation
% Settle Back 5 H 2 H 3100%/H
~ !
rise final rise
direction in air with no load and turn the stirrer off after
where:
checking.
H = free rise height of foam in millimetres
rise
8.2 Weigh an empty cup and record the weight.
H = final foam height in millimetres
final
8.3 Weigh reactants into the cup in accordance with previ-
10. Report
ously established order of addition.
10.1 Report all time results as previously agreed, typically
NOTE 2—Ensure that the temperature of the reactants is as specified
prior to use. to the nearest whole second.
D7487 − 08
10.2 Report Free Rise Density as previously agreed, a referee test method in case of dispute. Anyone wishing to
generally, Free Rise Density is reported to two decimal places. participate in the development of precision and bias data is to
contact the Chairman, Subcommittee D20.22 (Section
10.3 Report % Settle Back as previously agreed, generally
D20.22.01), ASTM, 100 Barr Harbor Drive, West
to the nearest percent.
Conshohocken, PA 19428.
11. Precision and Bias
12. Keywords
11.1 Precision—Attempts to develop a precision and bias 12.1 cream time; cup test; foam testing; formulated polyol;
statement for this practice have not been successful. For this free rise density; free rise height; free rise time; initiation time;
reason, only estimates of data on precision and bias can be isocyanate; polyurethane; pull time; raw material; resin blend;
given. Because this practice does not contain an acceptable settleback;sighback;sinkback;stringgeltime;tackfreetime;
numerical precision and bias statement, it shall not be used as top of cup time
APPENDIX
(Nonmandatory Information)
X1. EXAMPLE OF CUP FOAM TEST CONDITIONS FOR POLYURETHANE FOAM FORMULATIONS
X1.1 Scope X1.4.5 Tripour Beakers—polypropylene, 50-mL and
250-mL
...
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