1、Designation: D6409 99 (Reapproved 2014)Standard Practice forColor Tests with Sheepskin Skiver1This standard is issued under the fixed designation D6409; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers making color tests of all types ofvegetable tanning extracts and of vegetable tanning materialsto determine the col
3、or imparted to tanned skins.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 purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the u
4、ser 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:2D1517 Terminology Relating to LeatherD4901 Practice for Preparation of Solution of Liquid Veg-etable Tannin Ex
5、tractsD4905 Practice for Preparation of Solution of Solid, Pastyand Powdered Vegetable Tannin ExtractsD6405 Practice for Extraction of Tannins from Raw andSpent Materials2.2 ALCA Methods:A40 Color Tests with Sheepskin Skiver33. Terminology3.1 Definitions:3.1.1 For definitions of general leather and
6、tanning termsused in this practice refer to Terminology D1517.3.1.2 pickled skivera sheepskin skiver that has been pick-led in a solution of salt and sulfuric acid.3.1.3 sheepskin skiverthe grain split of a de-wooledsheepskin. A pickled skiver is used for this test.3.1.4 tanninan astringent substanc
7、e found in the variousparts of plants such as bark, wood, leaves, nuts, fruits, roots,etc.3.1.5 vegetable tanninsmixtures of substances (naturalproducts) obtained from plant tissues by water extractionwhich have the chemical and physical properties necessary toconvert animal hides and skins into lea
8、ther.4. Summary of Practice4.1 A specimen of pickled skiver is tanned with a sample ofvegetable tanning liquor in order to determine the color whichwill be imparted to a clear, clean hide or skin that is tannedwith this tanning liquor.5. Significance and Use5.1 This practice provides a standard proc
9、edure for compar-ing the color of leather tanned with different tanning extracts ormixtures of extracts or for monitoring the color consistency oftannery liquors.6. Apparatus and Reagents6.1 Pickled Sheepskin Skiver, specially and consistentlyselected for the color test.6.2 Borax, commercial grade s
10、uch as may be used in atannery.6.3 Containers, 10 and 3 L capacity and made of suitablematerial to be resistant to the chemicals and materials used inthe tanning procedure employed by this practice.6.4 Acetic Acid, glacial, commercial grade.6.5 Sodium Acetate, crystal, commercial grade.6.6 Sodium Ch
11、loride, crystal, commercial grade.6.7 Shake Bottles, 0.95 L (32 oz), with rubber stoppers. Thebottles shall be approximately 21.6 cm (8.5 in.) overall heightand 8.9 cm (3.5 in.) diameter. One quart canning jars (Mason-type) with plastic screw-on lids work well.6.8 Shaking Machine, rotating type, equ
12、ipped to hold 0.95 L(32 oz) bottles for end-over-end agitation of hide powder and1This practice is under the jurisdiction ofASTM Committee D31 on Leather andis the direct responsibility of Subcommittee D31.01 on Vegetable Leather. This testmethod has been adapted from and is a replacement for Method
13、 A40 of the OfficialMethods of the American Leather Chemists Association.Current edition approved Nov. 1, 2014. Published December 2014. Originallyapproved in 1999. Last previous edition approved in 2009 as D6409 99 (2009).DOI: 10.1520/D6409-99R14.2For referenced ASTM standards, visit the ASTM websi
14、te, 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.3Official Methods of the American Leather Chemists Association. Availablefrom the American Leather Chemists Assoc
15、iation, University of Cincinnati, P.O.Box 210014, Cincinnati, OH 45221-0014.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1analytical solution. The speed of rotation shall be 606 2 rpm,and the machine shall be so constructed that the
16、 side of theshake bottle adjacent to the rotating shaft shall be not less than5.1 cm (2 in.) nor more than 7.6 cm (3 in.) from the center ofthe shaft.6.9 Flat Dish, 250 to 300 mL capacity; a photographic trayworks well.6.10 Rubber Roller, photographic print roller works well.7. Test Specimen7.1 The
17、specimen shall consist of a liquor of four timesanalytical strength, prepared in a manner similar to the prepa-ration of solutions for analysis (Practices D6405, D4901,orD4905). The volume shall be 400 mL for Method I (9.2)or250mL for Method II (9.3).8. Preparation of Skiver8.1 The neck and flank po
18、rtions of the skiver shall betrimmed off, leaving a skin of uniform grain. The skiver maynow be cut into pieces approximately 10 by 15 cm (4 by 6 in.)or may be left whole. The skiver shall be placed in a solutionof 50 g of borax dissolved in 8 L of distilled water and at atemperature of 23 to 25C. I
19、t shall be stirred, or agitated,frequently and, at the end of 4 h, be transferred to a fresh boraxsolution, made up as before, be stirred several times and thenallowed to remain overnight therein at not less than 23C normore than 28C. Next morning, the skiver shall be transferredto 8 L of a 0.1 % so
20、lution of acetic acid, at 23 to 25C, bestirred, or agitated, frequently and, at the end of 3 h, be placedin a fresh solution of acetic acid of the same volume, strength,and temperature, and be stirred, or agitated, frequently. At theend of 3 h, the skiver shall be placed in 2 L of an aceticacid/sodi
21、um acetate buffer solution, at 23 to 25C, containing2.0 g glacial acetic acid and 10 g of sodium acetate crystals perlitre, and having a pH of 4.8 to 5.0. The skiver shall be stirredin this solution several times and then allowed to remaintherein overnight. Next morning, the skiver shall be transfer
22、redto a saturated solution of sodium chloride containing a largeexcess of the salt.9. Procedure for Making Color Tests9.1 Remove the salt from the skiver sample 10 by 15 cm (4by 6 in.) by shaking with four changes of distilled water, of 500mL each and at 23 to 25C, in a shake bottle for 15 min each.
23、9.2 Tanning Method I (Shake Method):9.2.1 Add the washed skiver to the 400 mL liquor sample(7.1) at 23 to 25C, contained in a shake bottle. Immediately,stopper the bottle and shake for 1 h in the shake machine.Allow the skiver to stand in the solution overnight at 23 to25C and then shake for one-hal
24、f hour next morning. Thentreat the skiver as described in 9.4.9.3 Tanning Method II (Layaway Method):9.3.1 Take a 50.0 mL portion from the 250 mL sample (7.1),dilute to 200 mL with distilled water at 23 to 25C, and pourinto a flat dish or tray (6.9). Completely immerse the washedskiver sample in thi
25、s solution, grain side up, and rock occa-sionally over a period of 1 h, or until the skiver is evenlycolored. Then discard the weak solution. Immediately pour theremaining 200 mL of the liquor sample into the dish andcompletely immerse the skiver. Rock it occasionally, cover it toprevent dust or dir
26、t from falling onto the skiver, and allow tostand overnight at 23 to 25C. Then treat the skiver asdescribed in 9.4.9.4 Post-Tanning Treatment:9.4.1 Wash the skiver, tanned as described in 9.2 or 9.3,byshaking with two changes of distilled water, of 800 mL eachand at 30 to 35C, for 10 min each, and r
27、inse with distilledwater, and squeeze out a number of times before, between, andafter the changes of water. Then spread it out on a glass surfaceand slick out lightly, using a rubber roller (6.10) with justenough pressure to remove the excess water. Then tack out theskiver, grain side down, on a boa
28、rd covered with filter paper,and put into a dark place to dry.9.4.2 After drying, the skiver is ready for color comparisonand evaluation by the standard procedure used at a particulartannery.10. Keywords10.1 color test; sheepskin skiver test; tanning color test;vegetable tannin analysisASTM Internat
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32、ds, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 99 (2014)2
