1、Designation: D7477 16Standard Test Method forDetermining the Area Stability of Wet Blue Submersed inBoiling Water1This standard is issued under the fixed designation D7477; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method provides a standard procedure fordetermination of the dimensional stability or area shrinkage ofa s
3、pecimen of Wet Blue that is submersed in boiling water fora specified time period. This test method is applicable to alltypes of Wet Blue.1.2 The values given in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.3 This test method does no
4、t apply to Wet White.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior t
5、o use.2. Referenced Documents2.1 ASTM Standards:2D6659 Practice for Sampling and Preparation of Wet Blueand Wet White for Physical and Chemical TestsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE177 Practice for Use of the Terms Precision and Bias i
6、nASTM Test Methods3. Summary of Test Method3.1 Asample cutting of Wet Blue is either taken directly outof the tanning drum or else is pre-soaked in water for 30 minor until it is completely re-hydrated (see 9.1 for details onre-hydration). The specimen to be tested is cut out from thisthoroughly hyd
7、rated sample cutting. The test specimen is thentotally submerged and suspended in boiling water. The testspecimen is removed 3.0 min after the water temperaturereaches 100C and begins to re-boil. As soon as the specimenhas cooled sufficiently to allow comfortable handling the arealoss is determined.
8、4. Significance and Use4.1 Determination of the hydro-thermal area stability of WetBlue provides information concerning the efficacy of thetanning process as well as the adequacy of the Wet Blue forintended end use applications where area stability is a particu-lar requirement. Relative area stabili
9、ty of chrome-tannedleather is a requirement for many applications such asbookbinding, shoe and boot components, upholstery, seals andgaskets, etc.4.2 This test method is suitable for use in development workand process control in the tannery and for specification testingof Wet Blue for domestic and i
10、nternational commercial pur-poses.5. Apparatus5.1 Beaker, standard, IL capacity. Other suitable containersmay be used so long as the dimensions are sufficiently large toenable suspension of the completely immersed test specimenwith no contact occurring with the sides and bottom of thecontainer durin
11、g the test. Particularly when non-standard testspecimens are used, the size and shape requirements of thecontainer are dependent on the dimensions of the specimen tobe tested.5.2 Thermometer, with a minimum scale reading to +110C,graduated in 1C, and having a 0.5C tolerance.5.3 Timer, with minimum 3
12、 min capacity and 1.0 s resolu-tion.5.4 Metal die, to cut specimens. The die should be con-structed of highly corrosion resistant alloy metal and must bemaintained in a clean and sharp condition to minimize distor-tion of the Wet Blue sample that may occur during thespecimen cutting operation. The r
13、ecommended specimen is asquare 76.2 by 76.2 mm (3.00 by 3.00 in.). However, other sizeand shape specimens can be used so long as the requirementsof Section 8 are met.1This test method is under the jurisdiction ofASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on
14、Wet Blue.Current edition approved Sept. 1, 2016. Published October 2016. Originallapproved in 2008. Last previous edition approved in 2013 as D7477- 08(2013).DOI: 10.1520/D7477-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org
15、. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.5 Measuring scale, ruler longer than the greatest dimen-sion of t
16、he test specimen, divided in millimeters (132 in.).5.6 Marking pen, Suitable water-proof marker or pen formarking the indicator points, on the hydrated Wet Blue grainsurface, to be used for measuring the specimen dimensions.6. Reagents and Materials6.1 Water, distilled or de-ionized laboratory water
17、 should beused, especially if there is any possibility of constituents in theavailable tap water affecting the results of this test.6.2 Glycerin (Glycerol), technical grade is adequate.6.3 Salt (Sodium Chloride), common table salt is adequate.7. Hazards7.1 All reagents and chemicals should be handle
18、d with care.Before using any chemical, read and follow all safety precau-tions and instructions on the manufacturers label or MSDS(Material Safety Data Sheet).8. Test Specimen8.1 The original sample cutting to be pre-soaked and the testspecimen cut from it shall be taken from the Wet Blueaccording t
19、o Practice D6659. Specifically, for a hide or side thecutting shall be taken from the “a” test area (the kidney area)of a hide or side. The number of samples to be tested shall beas described in Practice D6659 and need not be more than 12per 50 000 ft2of Wet Blue stock.8.2 The sample cutting taken f
20、rom the Wet Blue should belarge enough to permit the test specimen to be cut out with afresh edge no closer than 13 mm (0.5 in) to an edge of theoriginal cutting. The sample cutting from which the testspecimen should be taken, should have minimum dimensionsof approximately 101 by 101 mm (4 by 4 in.)
21、. A cutting takenstraight out of the tanning drum prior to wringing need not bepre-soaked and the test specimen can be cut out directly fromthis sample cutting.Acutting taken from Wet Blue at any pointfrom the wringing operation forward will need to be pre-soaked (see 9.1 for details on re-hydration
22、). The standard testspecimen shall be a square 76.0 mm (3.00 in.) on edge. Othersize and shape specimens can be used. It is recommended thatfor non-standard test specimens the minimum dimension (for aside of a rectangle or diameter of a circle ) be 51.0 mm (2.0 in.)and the maximum dimension (for a s
23、ide or diameter ) be 102mm (4.0 in.). Before a test specimen of non-standard dimen-sions may be used with this test method it must be rigorouslydemonstrated that the non-standard specimen gives identicalresults to that of the standard specimen for the particular WetBlue being tested.NOTE 1As an exam
24、ple of a non-standard specimen, a convenient sizefor test specimens could be a square exactly 100 mm on edge. Then, onthis specimen, a loss of 1 mm in each dimension is approximately (but notexactly) equal to 1 % loss in area. For instance, if a specimen experienceda loss of 4 mm in one dimension (a
25、ctual measurement after the test was96 mm determined by averaging the measured length of the two edgesparallel to that dimension) and a loss of 6 mm in the other dimension(actual measurement after the test was 94 mm determined by averagingthe measured length of the two edges parallel to that dimensi
26、on) then theapproximate area loss for that specimen would be 10 % (that is,4+6%).However, multiplication and subtraction followed by division (10 000 9024 mm2)/10 000 mm2 yields 9.76 % for the actual area loss. For mostapplications using this method, the area loss determined by simply addingthe dime
27、nsional loss values will give adequate results without goingthrough the mathematical calculations.8.3 Appropriate small holes may be punched in the testspecimen to facilitate the suspension of the submerged speci-men in the beaker of water during the test if J-hooks or S-hooksare used in conjunction
28、 with a rod across the top of the beaker.Alternative practices may provide suspension of the specimenby employing a net type structure attached to a rod across thetop of the beaker.9. Procedure9.1 Cuttings that are taken directly out of the tanning drumprior to dumping and wringing need not be re-hy
29、drated.Thorough hydration of the original sample cutting taken fromWet Blue after wringing shall be ensured by pre-soaking thiscutting for a minimum 30 min or until the cutting is completelyre-hydrated. All soaking for re-hydration should take placeunder ambient temperature conditions at the testing
30、 location.Cuttings taken from Wet Blue after wringing and that have notdried out usually re-hydrate within 30 min. Wet blue cuttingsthat have dried out somewhat may require significantly morethan 30 min to become completely re-hydrated. Wet bluecuttings that have become significantly air-dried may r
31、equiresoaking periods as long as overnight to re-hydrate completely.Re-hydration of the sample cutting can be accomplished bysoaking in a container or tray so long as the cutting iscompletely covered with water. Bending or flexing the cuttingwhile it is completely immersed in water or application of
32、 avacuum to facilitate removal of entrapped air may facilitatere-hydration. Complete hydration should be determined byweighing the sample at appropriate intervals during the soakingprocess until constant weight is achieved.Appropriate intervalsbetween weighings could be 10-15 min for cuttings that h
33、avebeen wrung but not dried out and 30-60 min or more forcuttings that have dried out significantly. Constant weight isachieved when the difference between successive weighings isless than 60.1 g. After the cutting has been completelyre-hydrated, the test specimen can be cut out from it.9.2 Before t
34、he test specimen is cut out from the completelyhydrated cutting, the beaker of boiling water shall be preparedso it is ready when the test specimen is cut out. A 1L beaker orother container shall be filled with sufficient water to gener-ously cover the test specimen when fully immersed, butleaving s
35、ufficient room to enable the immersion and removal ofthe test specimen without causing spillage of excess water ontothe hotplate surface. The water shall be brought to boil. If thetemperature is not exactly 100 6 0.5C sufficient glycerin orsalt shall be added to bring the boiling point up to but not
36、exceeding 100C.9.3 Prior to testing, the original area of the test specimenshall be determined. Measurement of the edge length of the testspecimen should be made a distance back from the physicaledge of the specimen in order to avoid problems with deformededges that may occur as a result of the test
37、ing conditions. Markthe grain surface of the specimen with indelible ink (see 5.6)toindicate the points of the original measurements. Make twoD7477 162measurements of each dimension, back 13 mm (0.50 in.) fromthe edges of the specimen, and average them to calculate thearea (A0= (S1a+S1b)/2x(S2a+S2b)
38、/2). The knowndimensions of the cutting die may be used to calculate theoriginal area of the test specimen; however, in order tofacilitate the measurement determinations after testing, thegrain surface of the specimen shall still be marked withindelible ink prior to testing to indicate the points of
39、 measure-ment as indicated above.9.4 The test specimen shall be totally submersed in theboiling water and suspended either by a hook or a net typedevice to prevent it contacting the bottom and sides of thecontainer. Start the timer when the water has again reached 1006 0.5C and begins to re-boil wit
40、h the same vigor it exhibitedprior to immersion of the specimen. After 3.0 min 6 5sremove the specimen from the water, cool it to a comfortableworking temperature by holding it under running cold water,and place it on a flat non-corrosive surface.NOTE 2Shortly after the test specimen is placed into
41、the boiling waterair is released from the specimen and can cause the water to appear to beboiling again. Before the timer is started, it is imperative to make sure thetemperature of the water is the same as it was before the specimen wasintroduced and that the water is boiling with the same intensit
42、y as it wasinitially.9.5 Re-measure the dimensions at the marked points andcalculate the area with the new values for the averageddimensions (AF= (S1a+S1b)/2x(S2a+S2b)/2). A negativevalue for the change in area (A0AF) indicates that thespecimen expanded or stretched rather than contracted orshrunk.9
43、.6 When multiple samples must be tested to a knownquality control or specification requirement on a pass/fail basisit may be more efficient to construct a rigid template with anoutline of the exact dimensions of the test specimen out ofnon-corrosive material such as poly (methyl methacrylate)(PMMA).
44、 Then make an additional outline on the template ofthe percent limit of the area loss acceptable for the specifica-tion. When using this measurement method option it isimperative to check the original dimensions of the specimenagainst the template outline for the original dimensions prior totesting.
45、 If the specimen edges do not match the templateoutline, that specimen must be discarded and another specimencut until the edges do match the template outline.After testing,place the specimen on the template and determine whether thedimensions are greater than the limit outline (Pass) or less thanth
46、e limit outline. If less than limit outline calculate the area lossas in Fig. 1.10. Calculation10.1 Calculate the area change as follows:Percent area change 5 A02 AF! 3100#/A0where:A0= original weight of the specimen, andAF= area of the specimen after testing.11. Report11.1 Report the area change to
47、 the nearest 0.1 %.12. Precision and Bias12.1 PrecisionThe precision of this test method is basedon a repeatability study of WK19533, New Test Method forDetermining the Area Stability of Wet Blue Submersed inBoiling Water, conducted in 2007. One laboratory comparedsix different materials under two d
48、ifferent conditions (“asreceived” and “dried out”), at one temperature. Every “testresult” represents an individual determination. The laboratorywas asked to submit five replicate test results, for each analysisand condition. Except for the limited number of reportinglaboratories, Practice E691 was
49、followed for the design andanalysis of the data; the details are given in ASTM ResearchReport No. D31-1011.312.1.1 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the “r” value for that material; “ r”istheinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.12.1.1.1 Repeatability limits are listed in Table 1 and Table2.12.1.2 Reproducibilty Limit (R)“ R
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