1、BRITISH STANDARD BS ISO 7211-3:1984 Textiles Woven fabrics Construction Methods of analysis Part 3: Determination of crimp of yarn in fabric ICS 59.080.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS ISO 7211-3:1984 This British Standard, having been prepared under the di
2、rection of the Materials and Chemicals Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 20 May 2002 BSI 20 May 2002 ISBN 0 580 39662 2 National foreword This British Standard reproduces verbatim ISO 7211-3:1984 and implements i
3、t as the UK national standard. It supersedes BS 2863:1984 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee TCI/24, Physical testing of textiles, which has the responsibility to: A list of organizations represented on this committee can be obtained on r
4、equest to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility o
5、f the BSI Standards Electronic Catalogue. 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 British Standard does not of itself confer immunity from legal obligations.
6、 aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages
7、 This document comprises a front cover, an inside front cover, the ISO title page, the ISO foreword page, pages 1 to 3, and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsInternati
8、onal Standard 7211 I3 INTERNATIONAL ORGANIZATION FOR STANDARDIZATIONWIEMYHAPOHAR OPrAHM3AMR f-l0 CTAHAPTM3AL any residual crimp is then ignored. When a figured fabric is under examination, it will be necessary to ensure that threads for testing are taken from a complete repeat of the pattern. 1 Scop
9、e and field of application This part of IS0 7211 specifies a method for the determination of crimp of yarn in fabric. The method is applicable to most woven fabrics but is unsuitable for fabrics manufactured in such a way as to render removal of the crimp from the yarns im- possible or impractical u
10、nder the specified straightening ten- sion. 2 Reference IS0 139, Textles - Standard atmospheres for conditioning and testing. 3 Definitions For the purposes of this part of IS0 7211, the following defini- tions apply : 3.1 percentage crimp: The mean difference between the straightened thread length
11、and the distance between the ends of the thread while in the fabric, expressed as a percentage of the latter. 3.2 straightening tension: The minimum force which, when applied to a yarn, removes the crimp caused by weaving. 4 Principle Threads are removed from a strip of fabric of known length, strai
12、ghtened by a tension which is varied according to the nature and linear density of the yarn and measured in the straightened state. The difference between the straightened length of the thread and the distance between the ends while in the fabric is expressed as a percentage of the latter. 5 Apparat
13、us 5.1 Thread straightening and measuring device, horizon- tal or vertical and complying with the following requirements: a) there shall be two yarn grips, each of which closes at its rear end first and when closed has parallel gripping- surfaces; b) it shall be possible to alter the distance betwee
14、n the grips; c) it shall be possible to measure the distance between the grips; d) a datum line shall be marked on one gripping-surface of each grip, about 2,5 mm from the edge nearest the other grip, which is visible when the grip is closed ; e) it shall be possible to apply the specified straighte
15、ning tension to the yarn through one of the grips. 5.2 Rule, graduated in the same units as the thread- straightening device. 5.3 Dissecting needle. 6 Conditioning and testing atmosphere One of the atmospheres for conditioning and testing textiles as defined in IS0 139 shall be used for conditioning
16、 and testing. 7 Test specimens Condition the sample for at least 16 h. Lay the conditioned fabric flat, free from tension and free from creases. Mark five rectangular strips on the fabric, two with their long sides parallel to the warp threads and three with their long sides parallel to the weft thr
17、eads. IS0 7211134984 (E) Ensure that each strip is at least ten threads in width, and is at least 20 times as long as the parts of the test Specimen that will be gripped within both jaws of the apparatus. Cut along the two short sides and one long side of each rec- tangular strip so as to produce fi
18、ve flaps in the fabric. Measure the distance between the two short sides of each flap in millimetres. NOTE - If it is desired to combine the determination of crimp with a determination of yarn linear density, it will be necessary to prepare a further two weftway strips and to ensure that five differ
19、ent weft packages are represented. All the strips should then be preferably of the same length and about 250 mm long and their width should be such as to contain at least 25 lengths of either warp or weft yarn, whichever is under examination. 8.3 Straightened length of thread Separate the grips so t
20、hat the chosen tension is developed gradually. Measure the straightened length of the thread in millimetres between the datum lines on the grips. 8.4 Number of threads Repeat the meas #urements to obtain the straightened 10 threads from each of the five rectan gular flaps. lengths of 9 Calculation a
21、nd expression of results For each group of 10 length in millimetres. threads, calculate the straightened 8 Procedure The percentage crimp C i.e. the difference between the mean straightened length and the length occupied by the threads in the fabric (that is the “flap” width) as a percentage of the
22、latter is given by the formula 8.1 Setting of apparatus Set the tensioning device (5.1) attached to one of the yarn grips (see 5.1) so that it will remove as much of the crimp as possible from the specimens without stretching them unduly. State the tension chosen when reporting the results. Straight
23、ening ten- sions for certain types of yarns are provided in the annex as a where L is the mean measured length, in millimetres, of 10 threads removed from the fabric; guide. 82 . By means of the dissecting needle (5.31, gently remove from a flap the middle of the outermost thread of a set of 10, lea
24、ving about 1 cm at each end still interlaced with the crossing L, is the length, in millimetres, occupied by the thread in the fabric, that is the flap width. Insertion of threads in the apparatus 10 Test report The test report shall include the following particulars: threads. a) a reference to this
25、 International Standard (IS0 7211/3) ; Remove one end of the thread from the crossing threads, holding it as close to the end as possible so as to avoid the loss of twist. Insert a slight excess of this end into one grip of the apparatus. Begin to close the grip so as to be able to withdraw the thre
26、ad under slight tension until its end coincides with the datum line. Close the grip completely (the portion of thread between the datum line and the edge of the grip should now be b) the standard atmosphere used (temperate or tropical); c) the specimen length of fabric, that is the flap width; d) th
27、e straightening tension used; e) the mean measured straightened length, in millimetres, for each group of 10 threads in warp and weft; approximately straight). Remove the other end of the thread from the fabric and insert it into the other grip in a similar manner. f) the percentage crimp in each gr
28、oup; 9) the mean percentage crimp for warp and weft; h) details of any deviation from the method. 2 IS0 7211/3-1984 (E) Annex Straightening tensions (Forms part of the Standard.) In the absence of instructions to the contrary, the tension to be used to straighten the threads after removal from the f
29、abric is given in the table. Table - Straightening tensions Yarn Cotton spun Woollen and worsted spun Man-made continuous filament non-textured Linear density Straightening tension tex cN * 7 tex or finer coarser than 7 tex (0,75 x tex value) (0,2 x tex value) + 4 15 tex to 60 tex (0,2 x tex value)
30、+ 4 61 tex to 300 tex (0,07 x tex value) + 12 all (0,5 x tex value) 3 BS ISO 7211-3:1984 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at
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