1、BRITISH STANDARD BS3424-18: 1986 Testing coated fabrics Part 18:Methods21A and 21B:Methods for determination of resistance to wicking and lateral leakage to air IMPORTANT NOTEIt is recommended that this Part be read in conjunction with the information in Part0 “Foreword and general introduction”. UD
2、C 677.077.652:678.066.2:677.017.6BS3424-18:1986 This British Standard, having been prepared under the directionof the Rubber StandardsCommittee, was published under the authority ofthe Board of BSI and comes intoeffect on 28February1986 BSI 03-1999 The following BSI references relate to the work on
3、this standard: Committee reference RUM/13 Draft for comment84/37091 DC ISBN 0 580 14910 2 Amendments issued since publication Amd. No. Date of issue CommentsBS3424-18:1986 BSI 03-1999 i Contents Page Foreword ii 1 Scope 1 2 Definitions 1 3 Method21A. Determination of capillary action wicking 1 4 Met
4、hod21B. Determination of lateral leakage to air 2 Figure 1 Coated fabric specimen prepared for wicking test 2 Figure 2 Arrangement of apparatus in wicking test 3 Figure 3 Permeameter 3 Figure 4 Preparation of test specimen for lateral leakage test 4 Publications referred to Inside back coverBS3424-1
5、8:1986 ii BSI 03-1999 Foreword In preparing this revision of method21of BS3424:1973 the Rubber Standards Committee was anxious to clarify any confusion that may have evolved over the years as to where the differences lay between wicking, resistance to liquids and porosity or gas transmission. Each o
6、f these effects is being dealt with separately in this revision of BS3424. In this respect attention is drawn to BS3424-0 “Foreword and general introduction”. Wicking is important to those users of coated fabrics which may be in contact with liquids or gaseous media for long periods of time in circu
7、mstances where the coated fabric should not become contaminated by, or permit the passage of media over, an area greater than the initial area of contact with the coated fabric. Similarly, where coated fabrics are used as gaskets or other types of seal, users require the coated fabric to exhibit lit
8、tle or no lateral leakage. There may however be applications where wicking may be desirable. In such circumstances the methods described in this Part of BS3424 are equally applicable. This Part supersedes method21of BS3424:1973. A British Standard does not purport to include all the necessary provis
9、ions 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. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an insi
10、de back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS3424-18:1986 BSI 03-1999 1 1 Scope This Part of BS3424 describes two methods for determining the resi
11、stance to wicking of fabrics coated on one or both sides or double texture or plied (laminated) fabrics. NOTEThe titles of the publications referred to in this Part of BS3424 are listed on the inside back cover. 2 Definitions For the purposes of this Part of BS3424 the following definitions apply. 2
12、.1 lateral leakage the passage of gases along or through the textile materials element of a coated fabric or along interstices formed by the textile element and the coating polymer of the coated fabric 2.2 wicking the passage of liquids along or through the textile materials element of a coated fabr
13、ic or along interstices formed by the textile element and the coating polymer of the coated fabric 3 Method21A. Determination of capillary action wicking NOTEMany coated fabrics, such as tarpaulins and salvage sheets, are exposed at their edges to water and other fluids, from which the coated fabric
14、 may be protecting machinery or other goods. This method of test is intended to provide evidence of the resistance of coated fabrics to capillary action wicking. 3.1 Principle A strip of coated fabric is suspended in an appropriate dye liquor. The distance which the dye liquor rises up the coated fa
15、bric in a given period of time is measured. 3.2 Apparatus and reagents 3.2.1 600mL beaker. 3.2.2 Stainless steel rods 40mm long and9.5mm in diameter. 3.2.3 Glass rod 150mm long and approximately9mm in diameter. 3.2.4 Clamp and retort stand. 3.2.5 Means for cutting a circular hole of10mm diameter in
16、the specimen. 3.2.6 Dye liquor, 0.2% aqueous solution of fluorescein sodium technical dye. 3.2.7 Shallow tray, at least60mm wideapproximately30mm long. 3.2.8 Ultraviolet or mercury vapour lamp. NOTEIf the dye liquor(3.2.6) is not suitable for the coated fabric under test, the details of any alternat
17、ive liquid medium used should be agreed between the contracting parties, and the details specified in the test report. 3.3 Preparation of test specimens Cut four test specimens, each150mm 50mm; two with their length in the longitudinal direction and two with their length in the transverse direction.
18、 Select the test specimens from widely separated parts of the sample, but not from within50mm of the selvedge. 3.4 Conditioning and testing Condition the test specimens in accordance with BS3424-2:1982, method4and carry out the test in this atmosphere. 3.5 Procedure 3.5.1 Single faced specimens. Dra
19、w an indelible line across both surfaces of each of the test specimens50mm from one end and at right angles to the longer edge. Make two incisions each18mm long and15mm from each edge parallel to the longer edges, as illustrated in Figure 1. Cut a circular hole of10mm diameter in the middle of the t
20、est specimen with the centre of the hole70mm from the line drawn across the face of the test specimen (see Figure 1). Prime the end of the test specimens with the liquid media, by allowing30mm of test specimen below the indelible line to rest in the shallow tray(3.2.7) containing a solution of dye l
21、iquor(3.2.6), and roll the stainless steel rod(3.2.2) twice over this length of test specimen in order to break down the liquid/air interface. Insert the stainless steel rod in the loop formed by the incisions in each specimen. Insert the glass rod(3.2.3) through the hole at the other end of the tes
22、t specimen. Lower the tensioned specimens suspended from the glass rod(3.2.3) into a600mL beaker(3.2.1) containing the dye liquor and immerse the test specimens in the dye liquor up to a point where the upper meniscus just touches the indelible line, as shown in Figure 2. After24h or such other peri
23、od as is appropriate to the performance specification remove the test specimens and immediately examine the wicking effect using the ultraviolet or mercury vapour lamp(3.2.8). Record the height to the nearest millimetre to which the dyestuff has risen above the indelible marked line (i.e.the distanc
24、e from the marked line to the uppermost extent of the wicking effect).BS3424-18:1986 2 BSI 03-1999 3.5.2 Double faced or multi-ply specimens. Where test specimens are double faced or multi-ply coatings, after immersion remove the test specimens from the dye liquor, remove the excess dye liquor and,
25、as the level of the dye liquor is not visible, remove the coating or separate the plies using an appropriate technique from BS3424-7:1982, method9. When the coating has been stripped from one face of the test specimen, record the height in millimetres to which the dyestuff has risen above the bottom
26、 of the test specimen and then deduct50mm (50mm being the height above the bottom of the test specimen that the marked line (see3.5.1) would normally be visible). Record this adjusted dimension as the wicking distance. NOTEAs wicking may not cease immediately when the test specimen is removed from t
27、he dye liquor, it is essential that the specimen is delaminated and the measurements are carried out as quickly as possible. 3.6 Expression of results Calculate the mean of the two highest wicking results and record this as the wicking distance (inmillimetres). 3.7 Test report The test report shall
28、include the following particulars: a) the description of the coated fabric; b) the wicking distance (in millimetres); c) reference to this method of test, i.e.method21A of BS3424-18:1986; d) details of any deviations from the standard test procedure, including the media, the dyestuff, time of immers
29、ion and temperature of test. 4 Method21B. Determination of lateral leakage to air NOTEMany coated and multi-ply laminated fabrics are used as gaskets and pressure seals. In such and similar cases it is important to the user that the fluid being contained does not escape by lateral leakage along the
30、textile materials element or along the interstices formed by the textile element and the coating polymer to the edges of the gasket or seal. 4.1 Principle An annulus of the test fabric, with outer and inner edges cut and unsealed, is held by a mounting fabric so that its outer edge is presented to a
31、ir at a specified pressure. The air passing laterally along the textile, emerges from the inner edge into water covering the test specimen, escaping as bubbles into a funnel covering the inner edge of the annulus and surmounted by a burette in which it is measured. 4.2 Apparatus 4.2.1 Permeameter, a
32、s shown diagrammatically in Figure 3. 4.2.2 Laboratory clamp and stand. 4.2.3 Burette. NOTEAn ordinary50mL burette cut off at approximately the30mL mark is recommended. 4.2.4 Glass funnel, 100mm in diameter, with its stem reduced to between30mm and40mm. Invert the funnel and butt joint the stem to t
33、he open end of the burette by50mm to70mm of close-fitting rubber tubing. 4.2.5 Roller, of mass2kg and length atleast60mm. 4.2.6 Scissors. 4.2.7 Adhesive. 4.2.8 Rubber tubing. 4.3 Preparation of test specimens 4.3.1 Cut, from a piece of impervious material, a cap (CC in Figure 4)115mm in diameter. On
34、 one face inscribe two concentric circles105mm and75mm in diameter respectively and mark the band between them. Figure 1 Coated fabric specimen prepared for wicking testBS3424-18:1986 BSI 03-1999 3 Figure 2 Arrangement of apparatus in wicking test Figure 3 PermeameterBS3424-18:1986 4 BSI 03-1999 4.3
35、.2 Cut from the test sample a disc (LL in Figure 4)242mm in diameter. On one face inscribe two circles as in4.3.1 and on the second face inscribe two concentric circles,230mm and200mm in diameter, and mark the bands between the circles on each face. Inscribe a third concentric circle62mm in diameter
36、 on the second face. 4.3.3 From any piece of fabric, which need not be impervious, that is strong enough and capable of adhering to the face of specimen LL, cut a disc (AAin Figure 4)350mm in diameter and on one face inscribe two concentric circles,230mm and200mm in diameter, and mark the band betwe
37、en them. 4.3.4 Make small slits or holes near the centres of specimen LL and disc AA. NOTEThese are to facilitate the entry of scissor points when these items are subsequently converted to annuli. 4.3.5 Using a method which will not damage the elastomer, clean the coated surfaces in the bands betwee
38、n the circles inscribed on CC, LL and AA to receive a self-curing adhesive, chosen to suit the elastomer of the coating. 4.3.6 Apply the adhesive to the bands, place the discs one on top of the other (i.e.LL on CC and AA on LL) with the bands of adhesive coinciding and make three passes over the joi
39、ns with the roller(4.2.5) allowing the roller to act under its own weight. 4.3.7 Set the specimen aside, for the adhesive to set. 4.3.8 Cut out the fabric bounded by the innermost circle on disc AA and then on specimen LL. 4.4 Conditioning and testing Condition the test specimen for24h in accordance
40、 with BS3424-2, method4and carry out the test in this atmosphere. 4.5 Procedure 4.5.1 Clamp the composite specimen in the permeameter(4.2.1) in the ordinary way, but omitting, as unnecessary, the greasing of the clamped margin. 4.5.2 Mount the burette(4.2.3) upside down, at about its mid-length, in
41、the clamp(4.2.2). Attach a piece of rubber tubing to the jet of the burette to allow suction to be applied. 4.5.3 Apply and maintain an air pressure of27.5kPa beneath the specimen. Figure 4 Preparation of test specimen for lateral leakage testBS3424-18:1986 BSI 03-1999 5 4.5.4 Flood the distended sp
42、ecimen with enough water to ensure that when the funnel and burette are charged the rim of the funnel is immersed but not touching specimen LL. 4.5.5 Open the tap in the burette, apply suction at the end of the rubber tubing to charge the funnel and burette, and close the tap. 4.5.6 Centre the funne
43、l over cap CC, read the burette and collect the escaping air for5min or until such time as20mL of air have been collected, whichever is the less. 4.5.7 Record the duration of the test and the volume of air collected. 4.6 Test report The test report shall include the following particulars: a) the des
44、cription of the coated fabric; b) the volume of air (in millimetres) collected per minute, without any correction for temperature or pressure; c) reference to this method of test, i.e.method21B of BS3424-18:1986; d) details of any deviation from the standard test procedure.6 blankBS3424-18:1986 BSI
45、03-1999 Publications referred to BS3424, Testing coated fabrics. BS3424-0, Foreword and general introduction 1) . BS 3424-2, Method 4 Conditioning and selection of test specimens. BS 3424-7, Method 9 Determination of coating adhesion strength. 1) Referred to in the foreword only.BSI 389 Chiswick Hig
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