Standard Test Method for Determining the Open Time of Hot Melt Adhesives (Manual Method)

SCOPE
1.1 This test method covers the manual determination of the open-time range of hot-melt adhesives under the stated conditions.  
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units in parentheses are provided for information only.  
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.

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Historical
Publication Date
09-Apr-1999
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Drafting Committee
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Ref Project

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ASTM D4497-94(1999) - Standard Test Method for Determining the Open Time of Hot Melt Adhesives (Manual Method)
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D 4497 – 94 (Reapproved 1999)
Standard Test Method for
Determining the Open Time of Hot Melt Adhesives (Manual
Method)
This standard is issued under the fixed designation D 4497; 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 specimens are examined later to determine the longest time
period, between application of the adhesive to one surface and
1.1 This test method covers the manual determination of the
mating with a second surface, which allows substantial bond-
open-time range of hot-melt adhesives under the stated condi-
ing.
tions.
1.2 The values stated in SI units are to be regarded as the
5. Significance and Use
standard. The inch-pound units in parentheses are provided for
5.1 This test method allows comparing the open time of
information only.
several hot melt adhesives.
1.3 This standard does not purport to address all of the
5.2 This test method is not intended to provide the open-
safety concerns, if any, associated with its use. It is the
time observed for a specific adhesive in a specific manufactur-
responsibility of the user of this standard to establish appro-
ing operation. This test method can be used to compare the
priate safety and health practices and determine the applica-
performance of adhesives which are represented to be identical
bility of regulatory limitations prior to use.
or to rank the open-time of a group of hot melt adhesives.
2. Referenced Documents
6. Apparatus
2.1 ASTM Standards:
2 6.1 Oven, which meets the precision required by the proce-
D 907 Terminology of Adhesives
dure, should be used to heat the adhesive sample and the
E 171 Specification for Standard Atmospheres for Condi-
3 applicator.
tioning and Testing Flexible Barrier Materials
6.2 Film Applicator— Multiple clearance 0.125 to 1.25 mm
E 691 Practice for Conducting an Interlaboratory Study to
4 (5 to 50 mil) square P.G. and T. Number 2 Film Applicator
Determine the Precision of a Test Method
capable of providing an applied film of adhesive having a
3. Terminology nominal width of 50 mm (2 in.).
6.3 Hand Thermometer, preferably metal, capable of mea-
3.1 Definitions— Several terms in this test method are
suring the temperature of the hot-melt with an accuracy of
defined in accordance with Terminology D 907.
61°C (62°F).
3.2 Definitions of Terms Specific to This Standard:
6.4 Primary Standard Substrate, 200 by 280 mm (8 by 11
3.2.1 open time—the time available between application of
in.), NBS Standard Reference Material 1810 (Liner Board).
the adhesive to the first substrate and the mating of the second
Substrates are to be conditioned as described in Specification
substrate which still results in a minimum of 50 % fiber tear
E 171.
when tested at ambient conditions.
6.5 Secondary Standard Substrate, 125 mm (5 in.) length in
4. Summary of Test Method the material direction cut to 19 mm (0.75 in.) wide, NBS
Standard Reference Material 1810 (Liner Board).
4.1 In this test method, open time is determined by bonding
6.6 Glass Beakers (600 mL), for melting the adhesive.
together with the adhesive, pieces of standard paper at intervals
6.7 Watchglass, to cover beaker.
of 5 s sequentially after the molten adhesive has been applied
6.8 Beakers, Tongs, and Protective gloves, for handling hot
using a heated film applicator on one surface. The bonded
vessels and applicators.
6.9 Transparent Pressure Sensitive Tape.
6.10 Stop Watch or Other Timer, graduated to at least 0.5 s.
This test method is under the jurisdiction of ASTM Committee D-14 on
Adhesives and is the direct responsibility of Subcommittee D14.50 on Hot Melt and
Pressure Sensitive Adhesives.
Current edition approved Dec. 15, 1994. Published February 1995. Originally
published as D 4497 – 85. Last previous edition D 4497 – 89. Film Applicator No. 2 is available from Precision Gage and Tool Company, 28
Annual Book of ASTM Standards, Vol 15.06. Volkenand Street, Dayton, OH 45410.
3 6
Annual Book of ASTM Standards, Vol 15.09. Available from National Institute of Standards and Technology (NIST),
Annual Book of ASTM Standards, Vol 14.02. Gaithersburg, MD 20899.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 4497 – 94 (1999)
6.11 Weighted Rectangular Block, having at least one
smooth and flat wood face, 50 by 12.5 mm (2 by 0.5 in.)
weighing 100 g (3.5 oz), the mass being uniformly distributed.
6.12 Micrometer or Thickness Gage, capable of measuring
to the nearest 0.025 mm (1 mil).
7. Sampling
7.1 The test sample should be representative of the adhesive
being tested.
8. Procedure
8.1 Add 300 6 10 g of the adhesive to the 600-mL glass
beaker and cover with a watch glass. Place the beaker
containing the adhesive into the oven and heat until at the
application temperature recommended by the manufacturer.
8.2 Concurrently heat the film applicator in the same oven
to condition it to the sample temperature as in 8.1. FIG. 2 Strips Drawn Back to Allow Hot Melt Application
8.3 Perform testing in a relatively draft-free room. While the
sample is melting, prepare the substrates for testing as shown
in Figs. 1 and 2. 1
8.6 Fill the applicator reservoir to approximately a ⁄4-in.
8.3.1 Tape the long sides of a piece of primary standard
level with conditioned hot adhesive.
substrate (see 6.4), minimum sheet size 100 by 280 mm (4 by
8.7 Move the applicator and the contained molten adhesive
11 in.), to a flat smooth surface of low thermal conductivity,
with one smooth motion over the length of the paper taking
specifically to a larger piece of chipboard (such as from the
approximately2sto complete the drawdown.
back of a tablet). Then tape the chipboard to an underlying
NOTE 1—Approximately2sis satisfactory. The purpose is to standard-
surface.
ize on a reasonable rate and eliminate an excessively fast or slow
8.3.2 Place the strips of the secondary standard substrate
drawdown which will affect the results.
(see 6.5) across the width of the primary substrate, as shown in
NOTE 2—Trial applications should be made to determine the proper
Fig. 1, leaving approximately 6 mm ( ⁄4 in.) between the strips.
applicator gap to lay down a specified film thickness. Normally, a gap of
The top strip should be approximately 75 mm (3 in.) below the
0.50 mm (20 mil) will lay down a film of 0.25 mm (10 mil). Variations in
top edge of the primary substrate. Using pressure sensitive
applied film thickness will occur because of differences in the hot flow
tape, attach one end of the strips to the primary substrate. Fold properties of the adhesive.
the unattached end of each strip back over the attached end so
8.8 Immediately after the film has been drawn down, start
that the primary substrate is exposed for application of the
the timer.
adhesive (see Fig. 2).
8.9 At5sonthe timer, or a longer time if it is known that
8.4 Remove the sam
...

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