1、Designation: D 7477 08Standard Test Method forDetermining the Area Stability of Wet Blue Submersed inBoiling Water1This standard is issued under the fixed designation D 7477; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of 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
3、 specimen 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 standard does not
4、 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 to use.2. Referenced Documents2.1 ASTM Standards
5、:2D 6659 Practice for Sampling and Preparation of Wet Bluefor Physical and Chemical TestsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3. Summary of Test Method3.1 A sample cu
6、tting 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 hydrated sample cutting. The test specimen is thentotally su
7、bmerged 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.4. Significance and Use4.1 Determination of the hydro-the
8、rmal 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 stability of chrome-tannedleather is a requirement for many appl
9、ications such as book-binding, 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 international commercial pur-poses.5. Apparatus5.1 Beake
10、r, 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 during the test. Particularly when non-standard testspecimen
11、s 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 min capacity and 1.0 s resolu-tion.5.4 Metal die, to c
12、ut 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 the specimencutting operation. The recommended specimen is a square 76.2by 76.2 mm (3.00 by
13、 3.00 in.). However, other size and shapespecimens can be used so long as the requirements of Section8 are met.5.5 Measuring scale, ruler longer than the greatest dimen-sion of the test specimen, divided in millimeters (132 in.).5.6 Marking pen, Suitable water-proof marker or pen formarking the indi
14、cator points, on the hydrated wet blue grainsurface, to be used for measuring the specimen dimensions.1This test method is under the jurisdiction ofASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved Sept. 1, 2008. Published Septe
15、mber 2008.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Driv
16、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Reagents and Materials6.1 Water, distilled or de-ionized laboratory water should beused, especially if there is any possibility of constituents in theavailable tap water affecting the results of this test.6.2 Glycerin (Glycerol), tec
17、hnical grade is adequate.6.3 Salt (Sodium Chloride), common table salt is adequate.7. Hazards7.1 All reagents and chemicals should be handled 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
18、. Test Specimen8.1 The original sample cutting to be pre-soaked and the testspecimen cut from it shall be taken from the wet blue accordingto Practice D 6659. Specifically, for a hide or side the cuttingshall be taken from the “a” test area (the kidney area) of a hideor side. The number of samples t
19、o be tested shall be asdescribed in Practice D 6659 and need not be more than 12 per50 000 ft2of wet blue stock.8.2 The sample cutting taken from 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 cutt
20、ing. The sample cutting from which the testspecimen should be taken, should have minimum dimensionsof approximately 101 by 101 mm (4 by 4 in.). 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 cuttin
21、g. A cutting 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). 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
22、 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 side 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
23、 that the non-standard specimen gives identicalresults to that of the standard specimen for the particular wetblue being tested.NOTE 1As an example 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
24、dimension is approximately (but notexactly) equal to 1 % loss in area. For instance, if a specimen experienceda loss of 4 mm in one dimension (actual 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
25、other dimension(actual measurement after the test was 94 mm determined by averagingthe measured length of the two edges parallel to that dimension) then theapproximate area loss for that specimen would be 10 % (that is,4+6%).However, multiplication and subtraction followed by division (10 000 9024 m
26、m2)/10 000 mm2 yields 9.76 % for the actual area loss. For mostapplications using this method, the area loss determined by simply addingthe dimensional loss values will give adequate results without goingthrough the mathematical calculations.8.3 Appropriate small holes may be punched in the testspec
27、imen 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 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 acr
28、oss 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-hydrated.Thorough hydration of the original sample cutting taken fromwet blue after wringing shall be ensured by pre-soaking thiscutting for a minimum 30 min
29、or until the cutting is completelyre-hydrated. All soaking for re-hydration should take placeunder ambient temperature conditions at the testing 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 some
30、what may require significantly morethan 30 min to become completely re-hydrated. Wet bluecuttings that have become significantly air-dried may requiresoaking periods as long as overnight to re-hydrate completely.Re-hydration of the sample cutting can be accomplished bysoaking in a container or tray
31、so long as the cutting iscompletely covered with water. Bending or flexing the cuttingwhile it is completely immersed in water or application of avacuum to facilitate removal of entrapped air may facilitatere-hydration. Complete hydration should be determined byweighing the sample at appropriate int
32、ervals during the soakingprocess until constant weight is achieved.Appropriate intervalsbetween weighings could be 10-15 min for cuttings that havebeen wrung but not dried out and 30-60 min or more forcuttings that have dried out significantly. Constant weight isachieved when the difference between
33、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 the 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 o
34、ut. A 1L beaker orother container shall be filled with sufficient water to gener-ously cover the test specimen when fully immersed, butleaving sufficient room to enable the immersion and removal ofthe test specimen without causing spillage of excess water ontothe hotplate surface. The water shall be
35、 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 notexceeding 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
36、 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 testing conditions. Markthe grain surface of the specimen with indelible ink (see 5.6)toindicate the points of the original measurements. Make twomeasurements o
37、f 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)/2). The known dimen-sions of the cutting die may be used to calculate the originalarea of the test specimen; however, in order to facilitate themeasurement determin
38、ations after testing, the grain surface ofD7477082the specimen shall still be marked with indelible ink prior totesting to indicate the points of measurement as indicatedabove.9.4 The test specimen shall be totally submersed in theboiling water and suspended either by a hook or a net typedevice to p
39、revent 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 with 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 temper
40、ature 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 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 mak
41、e sure thetemperature of the water is the same as it was before the specimen wasintroduced and that the water is boiling with the same intensity 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)/2
42、x(S2a+S2b)/2). A negativevalue for the change in area (A0AF) indicates that thespecimen expanded or stretched rather than contracted orshrunk.9.6 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 ri
43、gid template with anoutline of the exact dimensions of the test specimen out ofnon-corrosive material such as poly (methyl methacrylate)(PMMA). 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 o
44、ption it isimperative to check the original dimensions of the specimenagainst the template outline for the original dimensions prior totesting. If the specimen edges do not match the templateoutline, that specimen must be discarded and another specimencut until the edges do match the template outlin
45、e.After testing,place the specimen on the template and determine whether thedimensions are greater than the limit outline (Pass) or less thanthe 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
46、5 A0 AF! 3 100 /A0where:A0= original weight of the specimen, andAF= area of the specimen after testing.11. Report11.1 Report the area change to 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 forDete
47、rmining the Area Stability of Wet Blue Submersed inBoiling Water, conducted in 2007. One laboratory comparedsix different materials under two different conditions (“asreceived” and “dried out”), at one temperature. Every “testresult” represents an individual determination. The laboratorywas asked to
48、 submit five replicate test results, for each analysisand condition. Except for the limited number of reportinglaboratories, Practice E 691 was 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 o
49、btainedwithin 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” is the interval repre-senting the critical difference between two test results for thesame material, obtained by different operators using differentequipme
