1、CEN EN*ISO*L993 7.5 0 3i)0458% 0123561 411 BRITISH STANDARD Textile fibres - Determination of linear density - Gravimetric method and vibroscope method The European Standard EN IS0 1973 : 1995 has the status of a British Standard ICs 59.060 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY CO
2、PYRIGHT LAW BS EN IS0 1973 : 1996 CEN EN*ISO*L973 95 m 3404589 01235b2 358 m BS EN IS0 19f3 : 1996 Amd. No. Date The following BSI references relate to the work on this standard: Committee reference TCi24 Draft for comment 93/307688 DC ISBN O 580 25725 8 Committees responsible for this British Stand
3、ard Text affected The preparation of this British Standard was entrusted to Technical Committee TCY24, Physical testing of textiles, upon which the foliowing bodies were represented Association of Consulting Scientists Association of Suppliers to the British Clothing Industry British Apparel and Tex
4、tile Confederation British Measurement and Testing Association British Polyolen Textiles Association British Textile Machinery Association British Textile Technology Group British ThrowstersAssociation Furniture Indusby Research Association International Wool Secretanat Ministry of Defence SATRA Foo
5、twear Technology Centre Society of Dyers and Colourists Textile Finishers Association Textile Association This British Standard, having been prepared under the direction of the Sector Board for Materiais and Chemicals, was published under the authority of the Standards Board and comes into effect on
6、 15 May 1996 Amendments issued since publication O BSI 1996 CEN EN*ISO*L973 95 348458% 0123563 294 D BS EN IS0 1973 : 1996 Contents Committees responsible National foreword Page hide front cover ii Foreword Method 1 Scope 2 Normative references 3 Defjnitions 4 Principle 5 Apparatus 6 Conditioning an
7、d testing atmospheres 8 Procedure 9 Expression of resuits 10 Test report 7 sampling 2 3 3 3 3 4 4 4 4 5 6 Annexes A (informative) Examples of calculation of mean hear density 7 B (informative) Bibliography 10 ZA (normative) Normative references to international publications with their relevant Europ
8、ean publications 11 O BSI 1996 i CEN ENxISOr1973 75 31VDV587 0423554 120 BS EN IS0 1973 : 1996 National foreword This British Standard has been prepared by Technical Committee TCV24 and is the Engltsh language version of EN IS0 1973 : 1995 T b) individual fibres Useful data can be obtained on man-ma
9、de fibres and, with less precision, on natural fibres. The procedures can be applied only to fibres which can be kept straight and, in the case of bundles, par- allel, during test preparation. These methods are properly applicable when the fibres are readily freed of crimp. They are not applicable t
10、o tapered fibres. NOTE 1 to hollow and flat (ribbon-like) fibres. The vibroscope method may not be applicable 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publica- tion, t
11、he editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the standards indicated below. Members of IEC and IS0 maintain registers of
12、cur- rently valid International Standards. IS0 139: 1973, Textiles - Standard atmospheres for conditioning and testing. IS0 11 30:1975, Textile fibres - Some methods of sampling for testing. IS0 6989:1981, Textile fibres - Determination of length and length distribution of staple fibres (by measurem
13、ent of single fibres). 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 tension: Force tending to cause the extension of a body. NOTE 2 the linear density or cross-sectional area. In textile testing, the tension applied is based on 3.2 tensioning fo
14、rce: Force effective on a fibre specimen during the vibroscope test. 4 Principle Two methods for determining linear density are de- scribed: 4.1 Gravimetric method (direct method by weighing), for bundles of fibres Specimens of a given length are weighed on a bal- ance. This method is applicable to
15、bundles of fibres. 4.2 Vibroscope method, for individual fibres Individual fibres of a given length and under specified tension are subjected to vibration at resonance fre- quency. The linear density is determined from the conditions of the resonance state, .e. the resonance frequency, Lhe langth of
16、 the fibre and the tensioning force. The linear density is read directly on the scale of the vibroscope apparatus. This method assumes that the linear density of the tested length of the fibre is constant. CEN EN*ISO*1973 95 U 3404589 0123568 87b Page 4 EN IS0 1973 : 1995 NOTE 3 For high-modulus fib
17、res (e. aramid fibres) the use of the vibroscope method should be agreed on by the interested parties, because the high stiffness of such fibres may influence the results. 5 Apparatus 5.1 Gravimetric method 5.1.1 fibres to an accuracy of at least k 1 %. Balance, suitable for weighing the bundles of
18、5.1.2 Device for cutting the bundles under tension to a length known within an accuracy of 1 % and allowing an adjustment of the tension of the bundles to be cut. For example, two razor blades set parallel in a suitable holder may be used. 5.1.3 Combsorter, for preliminary alignment of fi- bres. 5.1
19、.4 Textile support fabric, of a colour contrasting with that of the fibres to be tested. 5.1.5 Glass plate, measuring approximately 1 O0 mm x 200 mm, with one polished edge. 5.1.6 Forceps. 5.2 Vibroscope method 5.2.1 Vibroscopel, having the following accuracy: a) b) C) 6 The applied tensioning force
20、 shall be within the range of The error in the vibroscope reading of resonance frequency measured or applied shall not exceed I 0,5 %; The error in the vibroscope reading of vibration length of the fibre shall not exceed f I YO. Conditioning and testing atmospheres The atmospheres for preconditionin
21、g, conditioning and testing shall be in accordance with IS0 139. 7 Sampling To ensure that the laboratory sample is representative of the material and that the test specimen taken from the laboratory sample is representative of that sam- ple, sampling shall be carried out in accordance with IS0 1130
22、. 8 Procedure 8.1 Gravimetric method 8.1.1 Condition the test specimens and carry out the tests in the standard atmosphere for testing as spec- ified in clause 6. 8.1.2 From the laboratory test sample, take ten tufts having a mass of several milligrams and bring the fi- bres of each tuft into parall
23、el alignment by carefully combing them several times with the combsorter (5.1.3). 8.1.3 Cut the middle part of each combed tuft to a given length (as great as possible), under the mini- mum tension necessary to remove crimp, by means of the cutting device (5.1.2). Take the necessary precautions so t
24、hat there are no free fibre ends any- where except at the two ends of the cut bundle. 8.1.4 Place the ten bundles so obtained on the tex- tile support fabric (5.1.4) and cover them with the glass plate (5.1.51, from the polished edge of which they shall protrude slightly. 8.1.5 From each of the ten
25、bundles in turn, take out five fibres so as to form a bundle of 50 fibres, in each case drawing the fibres from one cut end. Make at least ten of these bundles. Recondition the specimen in the atmosphere specified in clause 6, if necessary. Weigh these bundles individually, using the balance (5.1.11
26、, to an accuracy of 1 %. NOTE 4 If the bundle of 50 fibres cannot be weighed on the balance to the required 1 % accuracy, the number of fi- bres may be increased up to 500. 8.2 Vibroscope method 8.2.1 Check the vibroscope, before examining the laboratow test sample, as follows. Test 1 O0 individual
27、fibres using the vibroscope in question. Test these same fibres, for comparison, using the gravimetric method. Calculate the arithmetic mean and coefficient of variation of the vibroscope readings of linear den- sity. If the coefficient of variation of the vibroscope readings is larger than 10 %, th
28、e sample is not suit- able for determination of linear density using this vibroscope. 1) For a list of suppliers of suitable vibroscope equipment, apply to the Secretariat of IS0 Technical Committee 38. - CEN EN*ISO*L973 95 = 3404589 OI123569 702 Page 5 EN IS0 1973 : 1995 Weigh the bundle of 1 O0 fi
29、bres that have been tested with the vibroscope using the balance (5.1.1). Meas- ure the length of all fibres in accordance with IS0 6989 with an accuracy of k 1 %. Or, where ap- propriate, cut the 100 fibres to a known length using the cutting device (5.1.2). Calculate the mean linear density, pi,b,
30、 of the fibre, expressed in decitex, using the following formula: i= 1 where q, is the mass, in milligrams, of the fibre bundle; 1, is the length, in miliimetres, of the ith fibre in the bundle. Compare this mean linear density with the mean value of the linear density readout on the vibroscope. The
31、 relative difference shall not exceed b) complete identification of the sample tested; c) type of package, its condition (e.g. raw, bleached, dyed); d) conditioning and testing atmosphere used; e) sampling scheme used, number of specimens tested; f) test method (gravimetric or vibroscope) and type o
32、f tester used; g) any deviation, by agreement or otherwise, from the procedure specified. 10.2 Gravimetric test results a) Length of the cut bundle; b) number of bundles tested; c) mean linear density of the sample, in decitex; d) coefficient of variation, as a percentage; e) 95 % confidence interva
33、l, in decitex. 10.3 Vibroscope test results a) Number of fibres tested; b) tensioning force used; c) mean linear density of the sample, in decitex; d) coefficient of variation as a percentage; e) 95 % confidence interval, in decitex. CEN EN*ISO*L973 95 U 34c14.5A9 61123571 3b0 D Page 7 EN IS0 1973 :
34、 1995 Annex A (informative) Examples of .calculation of mean linear density For additional details see IS0 2602. A.1 Gravimetric method - Bundles of 50 fibres A.l.l Data Values of weighings of ten bundles, in milligrams: 0,385; 0,388; 0,381; 0,379; 0,375; 0,383; 0,388; 0,377; 0,400; 0,381. Cut lengt
35、h: 50 mm. A.1.2 Calculations Mean linear density of the fibre in each bundle, in decitex: 4 1,54; 1.55; 1.52; 1.52; 1,50; 1,53; 1.55; 1,51; 1,60; 1,52. m, x10 = m, 4 50 x 50 P1.b = 3 lo = where mb n, is the mass of the fibre bundle, in milligrams; is the number of fibres in the bundle; I, is the len
36、gth of the individual fibres in the bundle, in millimetres. Mean linear density of the fibres in all bundles: pl = 1,53 dtex. Coefficient of variation: v = 1.8 %. Confidence interval: A = f - = f 0,02 dtex k where S “b t is the standard deviation, calculated to be 0,028 dtex; is the number of fibre
37、bundles; IS the Students distribution, taken from a statistical chart and equal to 2.26 for n, = 10 and a probability levei P = 95 %. CEN EN*ISO*L973 95 W 3404589 Q1i2352 2T Page 8 EN IS0 1973 : 1995 Value percentage of the confidence As this value is less than 2 % limit mean linear density of the s
38、ample. A.2 Vibroscope method - interval: specified in 9.1.4, the calculated mean of 1.53 dtex can be accepted as the Individual fibres Values of 50 individual determinations of linear density in decitex: 1,51; 1,47; 1.42; 1,64; 1,38; 1,55; 1,41; 1.56; 1,44; 1.41; 1,37; 1,66; 158; 1,41; 1.52; 1.68; 1
39、.63; 1,40; 1.73; 1.67; 1,53; 1,40; 1,39; 1.58; 1,38; 1,40; 1,67; 1.60; 1.50; 1.73; 1,61; 1,36; 1,37; 1.49; 1.23; 1,60; 1,72; 1,71; 1,47; 1,38; 1,45; 1.28; 1,58; 1.70; 1.58; 1.53; 1,48; 1.55; 1.53; 1.36. Mean linear density of the 50 individual fibres: pi = 1.51 dtex. Coefficient of variation: v = 8,
40、3 % Confidence interval: A=f - - f 0.04 dtex where S n is the standard deviation, calculated to be 0,125 dtex; is the number of determinations; t is the Students distribution, taken from a statistical chart and equal to 2,Ol for n = 50 and a probability level P = 95 %. Value percentage of the confid
41、ence interval: A % =1oo.h= f 2.3 % PI As this value is greater than the 2 % limit specified (Asp) in 9.2.4, the number of tests must be increased by a quantity “2, calculated by the formula: where, for our example: ni = 50; v = 8.3 %; Asp = 2 %; t = 2.01. The additional number of tests is thus: _ CE
42、N EN*ISO*L973 95 m 3it04589 0123573 133 m Page 9 EN IS0 1973 : 1995 The values from the 20 additional determinations of pi are: 1,67; 1,53; 1.41; 1.45; 1,68; 1.73; 1.56; 1.54; 1,70; 1.52; 1,49; 1,63; 1.70; 1.52; 1,36; 1,52; 1,50; 1.39; 1,35; 1,37. The mean of 50 + 20 individual determinations of lin
43、ear density is: pi = 1,52 dtex. The new standard deviation, s, is calculated to be 0,125 dtex, the coefficient of variation, v = 8,2 %, and the new confidence interval, A, becomes f 0,03 dtex. The value percentage of the confidence interval is thus now ac- ceptable: 100-A Pi A % = - = 2,0 % _ CEN EN
44、*ISO*L973 95 M 3404589 0123574 0T Page 10 EN IS0 1973 : 1995 Annex B (informative) Bibliography l IS0 1144:1973, Textiles - Universal system for designating linear density (Tex System). 121 IS0 2602:1980, Statistical interpretation of test results - Estimation of the mean - Confidence interval. CEN
45、EN*ISO*L973 95 3413458% 0323575 Tob Page 11 EN IS0 1973 : 1995 Annex ZA (normative) Normative references to international publications with their relevant European publications This European Standard incorporates by dated or undated reference, provisions from other publications. These normative refe
46、rences are cited at the appropriate places in the text and the publications are listed heder. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the lat
47、est edition of the publidon referred to applies. IEC publication Date litle IS0 139 1973 Tata - Standaml atmspheres for cmditioning and testing ENMD Date EN 21039 1992 O BSI 1996 BS EN IS0 1973 : 1996 List of references See national foreword. O BSI 1996 - BS EN IS0 1973 : 1996 BSI 389 Chiswick High
48、Road London w4 4AL - CEN EN*ISO*L973 95 3404589 0323577 8/37 BSI - British Standards Institution BSI is the independent donal body responsible for preparing British Standasds. It presents the UK view on standards in Europe and at the intedonal level. It is incorporated by Royal Charter. Contract req
49、uirements A British Standard does not purport to include ail the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quaJlty of our products and seMces. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform t
