1、BRITISH STANDARD BS 6715:1991 Specification for Chamois leatherBS6715:1991 This British Standard, having been prepared under the directionof the Textiles and Clothing Standards Policy Committee, was published underthe authority of the BoardofBSI and comes into effect on 31 January 1991 BSI 12-1999 F
2、irst published January 1987 Second edition January 1991 The following BSI references relate to the work on this standard: Committee reference TCM/17 Draft for comment 88/37293 DC ISBN 0 580 19242 3 Committees responsible for this British Standard The preparation of this British Standard was entruste
3、d by the Textiles and Clothing Standards Policy Committee (TCM/-) to Technical Committee TCM/17, upon which the following bodies were represented: British Clothing Industry Association British Footwear Manufacturers Federation British Leather Confederation Chief and Assistant Chief Fire Officers Ass
4、ociation Consumer Policy Committee of BSI Footwear Distributors Federation Hides and Allied Trades Improvement Society Institute of Trading Standards Administration Ministry of Defence Overseas Development Natural Resources Institute SATRA Footwear Technology Centre Scottish Hide, Skin and Tallow Ma
5、rkets Limited Society of Leather Technologists and Chemists Amendments issued since publication Amd. No. Date CommentsBS6715:1991 BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Materials and manufacture 1 4 Classification by quality 1 5
6、Sampling 1 6 Conditioning 1 7 Physical properties 1 8 Chemical properties 2 9 Marking 2 Appendix A Sampling in cases of dispute 3 Appendix B Determination of water absorption 3 Table 1 Chemical properties 2 Table 2 Number of leathers to be tested in cases of dispute 2 Publication(s) referred to Insi
7、de back coverBS6715:1991 ii BSI 12-1999 Foreword This British Standard has been prepared under the direction of the Textiles and Clothing Standards Policy Committee and is a revision of BS6715:1987 which is withdrawn. The principal changes from the previous edition are as follows. a) Reference to BS
8、4804, which is considered obsolete and out of line with commercial practice, has been deleted. b) There is a recommendation that size should now be measured in accordance with the mechanical pinwheel method currently being discussed within the International Organization for Standardization and the I
9、nternational Council of Tanners. c) In cases of dispute, for measurement of size and mass per unit area, it is now considered that greater consistency may be achieved if samples are preconditioned for12h at a relative humidity not less than75% and a temperature not greater than30 C and subsequently
10、conditioned as specified in BS3144. At the time of publication, no corresponding International Standard exists. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a Briti
11、sh Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments in
12、corporated. This will be indicated in the amendment table on the inside front cover.BS6715:1991 BSI 12-1999 1 1 Scope This British Standard specifies requirements for the materials, manufacture, chemical and physical properties, sampling and testing and marking of chamois leather. NOTEThe titles of
13、the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard, the definitions given in BS2780 apply, together with the following. 2.1 whole skins skins which may have been given a small amount of trimming but not so as to
14、reduce them to rectangular form 2.2 flay cuts cuts in the chamois leather caused by a knife when the skin was removed from the animal 2.3 cockly places areas of the skin which do not absorb the dressing in the same way as the rest of the skin and are harder in texture and usually darker in colour 2.
15、4 holes holes through the skin greater than1mm in diameter 2.5 sewings holes in a chamois leather which have been sewn up 3 Materials and manufacture 3.1 Materials Chamois leather shall be prepared from either sheepskins or lambskins from which the grain has been removed by frizing or splitting. 3.2
16、 Manufacture Chamois leather shall be manufactured by one of the following methods of processing. a) Full oil process. The skins shall be tanned with marine oils. b) Combination process. The skins shall be tanned with formaldehyde, or other aldehyde, and marine oils. 4 Classification by quality 4.1
17、General Chamois leather shall be classified according to its faults in accordance with4.2 and4.3. 4.2 First class A chamois leather shall be classified first class if all the following apply: a) the chamois leather is soft, and of even thickness; b) the chamois leather is finished on both sides; c)
18、the chamois leather is free from thin places, flay cuts, hard and cockly places, holes and sewings. 4.3 Second class A chamois leather shall be classified second class if all the following apply: a) the chamois leather is soft; b) the chamois leather is finished on one or both sides; c) the chamois
19、leather is lightly flayed,i.e.contains a maximum of three flay cuts and scar tissue, each of which is not greater than25mm in length; d) the chamois leather is free from hard and cockly places, holes and sewings. 5 Sampling Samples shall be taken for testing in accordance with method1of BS3144:1968
20、except in cases of dispute, when the sampling procedure given inAppendix A shall be followed. 6 Conditioning Samples shall be conditioned in accordance with BS3144. In cases of dispute, for measurement of size and mass per unit area, samples shall be preconditioned for12h at a relative humidity not
21、less than75% and a temperature not greater than30 C and subsequently conditioned as specified in BS3144. 7 Physical properties 7.1 Size Chamois leather shall be supplied as trimmed whole skins or squares. NOTEIt is recommended that size should be measured by the mechanical pinwheel method currently
22、under review by the International Organization for Standardization (ISO) and the International Council of Tanners 1) . 1) For information on the availability of suitable apparatus to perform this measurement, apply to Enquiry Section, BSI, Linford Wood, Milton Keynes, MK146LE quoting the number of t
23、his standard and the clause number referring to the items concerned. Enclose a stamped addressed envelope for reply.BS6715:1991 2 BSI 12-1999 Table 1 Chemical properties 7.2 Mass per unit area The minimum mass per unit area shall be0.300kg/m 2(0.0300g/cm 2 ) for first class leathers (see4.2) and0.22
24、5kg/m 2(0.0225g/cm 2 ) for second class leathers (see4.3). 8 Chemical properties The finished leather shall comply with the requirements given inTable 1, when tested in accordance with the methods specified therein. Table 2 Number of leathers to be tested in cases of dispute 9 Marking 9.1 The leathe
25、r shall be marked with the manufacturers name, trade mark or other means of identification. 9.2 The leather shall be supplied with a label or invoice marked with the following information: a) the number and date of this British Standard,i.e.BS6715:1991; 2) b) the classification, first or second clas
26、s (see clause4); c) size (see7.1); d) a warning that “chamois leather is a natural product and may subsequently permanently relax if stored in or exposed to a warm, dry atmosphere”. NOTEThe Nato stock number, 8330-99-132-7703, is marked on Ministry of Defence items only. Chemical property Test proce
27、dure Requirements for first class and second class leathers pH Method 9 of BS 1309:1974 5.0 to 10.5 Oils and fats soluble in dichloromethane Method 4 of BS 1309:1974 15% max. a Sulphated total ash Method 6 of BS 1309:1974 24% max. a Total oils, fat and ash b Methods 4 and 6 of BS 1309:1974 35% max.
28、a Water absorption Appendix B 375% min. a NOTE 1For Ministry of Defence items only, the minimum percentage water absorption is400%. NOTE 2If sampling has been carried out in accordance with Appendix A, unless each sample meets all the chemical requirements specified in Table 1, the lot should be dee
29、med not to comply with this standard. If only one sample fails to meet only one requirement, a further set of samples should be drawn (seeTable 2) and repeat tests made for that requirement. If any one of the repeat samples does not meet that requirement, the lot should be deemed not to comply with
30、this standard. a Values are expressed as a percentage based on the mass of fat-free leather containing 14% moisture. b This property is an arithmetic sum of oils, fats, other solubles and sulphated total ash. Number of leathers in lot Minimum number of leathers to be tested For mass per unit area Fo
31、r all other requirements Up to 500 10 2 501 to 1 000 20 2 1 001 to 2000 20 3 Over 2000 20 4 2) Marking BS 6715:1991 on or in relation to a product represents a manufacturers declaration of conformity,i.e.a claim by or on behalf of the manufacturer that the product meets the requirements of the stand
32、ard. The accuracy of the claim is therefore solely the responsibility of the person making the claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable.BS6715:1991 BSI 12-1999 3 Appendix A Sampling in cases of dispute A.1 Draw the numb
33、er of leathers to be tested from the lot in accordance withTable 2. A.2 Draw the leathers for test so as to be representative of the lot and sample in accordance with method1of BS3144:1968. Appendix B Determination of water absorption B.1 Principle A specimen of leather, after initial wetting, is im
34、mersed in water for a given time, allowed to drain for a given time and weighed. After drying and reweighing, the absorption of water is calculated on the basis of fat-free leather containing14% moisture. B.2 Apparatus and reagents B.2.1 Distilled or deionized water B.2.2 Balance, with an accuracy o
35、f 0.01g. B.2.3 12 polyvinyl chloride (PVC) rods, of approximate dimensions25mm 10mm diameter and nominal mass2.5g. B.2.4 Glass plate, of minimum dimensions300mm square and inclined at a nominal angle of45 . B.2.5 Wide necked polyethylene jars, of1L capacity, with watertight closures. B.2.6 Rotating
36、shaker, operating at50 10 r/min. B.2.7 Air oven, capable of being maintained at102 2 C. B.2.8 Desiccator B.3 Test specimen Cut a test specimen of minimum dimensions120mm 180mm from the butt of whole skins or the middle part of squares. Avoid the backbone when sampling whole skins. The180mm side shal
37、l be parallel to the backbone. B.4 Procedure B.4.1 Pour 350mL of distilled or deionized water(B.2.1) at20 2 C into a1L polyethylene jar (B.2.5). Add the test specimen of chamois leather and12PVC rods (B.2.3). Place on a rotating shaker(B.2.6) for15min. Pour off the water and repeat with a further350
38、mL of distilled or deionized water. Remove the test specimen and wring by hand. B.4.2 Place the washed test specimen in a1L polyethylene jar. Add350mL of distilled or deionized water and12PVC rods and place on the rotating shaker for15min. Remove the test specimen without squeezing and place on the
39、glass plate (B.2.4) such that the diagonal is parallel to the inclined axis of the plate. Allow to drain for2min. B.4.3 Weigh to the nearest0.1g. B.4.4 Wring out the test specimen by hand and allow to dry at room temperature for24h. B.4.5 Dry the test specimen in an air oven (B.2.7) at102 2 C for no
40、t less than18h. Cool in a desiccator (B.2.8) for30min. Reweigh. B.5 Calculation The percentage of water P retained by the test specimen, calculated on fat-free leather containing14% moisture, is given by the formula: where where B.6 Test report The test report shall include the following information
41、: a) identification of sample and date of test; b) method of test,i.e.determination of water absorption, as described inAppendix B of BS6715:1991; c) the percentage water absorption; d) details of any deviations from the procedure. W 1 is the initial mass of the test specimen determined in accordanc
42、e withB.4.3 (in g); W o is the final mass of the test specimen determined in accordance with B.4.5 (in g); G is the percentage fat determined in accordance with method 4 of BS 1309:1974.4 blankBS6715:1991 BSI 12-1999 Publication(s) referred to BS 1309, Methods of sampling and chemical testing of lea
43、ther. BS 2780, Glossary of leather terms. BS 3144, Methods of sampling and physical testing of leather. BS 6715:1991 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on sta
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