1、BRITISH STANDARD BS3424-19: 1989 Testing coated fabrics Part19: Methods22A,22B and22C. Determination of sulphur staining IMPORTANT NOTE.It is recommended that this Part be read in conjunction with the information in Part0 “Foreword and general introduction”. UDC677.077.652:678.066.2:677.017:677.014.
2、55:543.845BS3424-19:1989 This British Standard, having been prepared under the directionof the Rubber StandardsPolicy Committee, waspublished under the authorityof the Board of BSIandcomes into effect on 30 November 1989 BSI05-1999 The following BSI references relate to the work on this standard: Co
3、mmittee reference RUM/13 Draft for comment87/37204DC ISBN 0 580 17561 8 Foreword Some coated fabrics contain substances in the coating, or the substrate, such as copper and lead pigments or compounds, that are liable to discolour as a result of reaction with sulphur or its compounds. Method22A gives
4、 an indication of the discoloration of a coating that may eventually occur under the most severe conditions of use. This method is intended for use when the appearance or aesthetic properties of the coating are important. Consideration was given to a gaseous method using hydrogen sulphide, but as hy
5、drogen sulphide is extremely toxic and desensitizing, greater skill would be required in its handling and more sophisticated equipment would be needed. It was therefore decided to specify only the aqueous method, particularly as it provides a test that is sufficiently stringent for most purposes. Me
6、thods22B and22C are designed to assess the degree of staining caused by free sulphur in the coating polymer to silver and copper components, respectively. The tests are essentially concerned with protecting electrical components from the corrosive effects of free sulphur in the coating polymer. This
7、 Part supersedes method22 of BS3424:1973. 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.
8、 Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to4, an inside 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 the inside
9、 front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS3424-19:1989 BSI 05-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 Method22A. Sodium sulphide method 1 3 Method22B. Corrosive sulphur test (Silver stain test) 2 4 Method22C. Corrosive sulphur test (Coppe
10、r stain test) 3 Publications referred to Inside back coverii blankBS3424-19:1989 BSI 05-1999 1 1 Scope This Part of BS3424 describes a method for assessing the resistance of coated fabrics to discoloration by sulphur or its compounds and methods for assessing staining caused by free sulphur in the c
11、oating polymer of coated fabrics to silver and copper components. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Method22A. Sodium sulphide method 2.1 Principle A test specimen of coated fabric is immersed in acidified sodium sulphide solution
12、for a given duration. The colour of the test specimen is compared with the original sample immediately after removal from the sodium sulphide solution, and then again after24h. Any change in colour is reported by reference to the grey scale for assessing staining. 2.2 Apparatus and reagents 2.2.1 Hy
13、drated sodium sulphide (Na 2 S.9H 2 O), analytical reagent grade. 2.2.2 Concentrated hydrochloric acid, standard laboratory reagent grade. 2.2.3 Fume cupboard. 2.2.4 Three 250mL beakers. 2.2.5 Grey scale for assessing staining complying with BS1006:A03. 2.2.6 Glass rod for stirring the test solution
14、. 2.2.7 Clock glasses. 2.2.8 Measuring cylinders. 2.2.9 Balance accurate to 10mg. 2.2.10 Distilled water complying with BS3978. 2.3 Test specimen Cut a test specimen measuring50mm 50mm from the sample, but not within50mm of the selvedge. 2.4 Preparation of test solution Caution. Hydrogen sulphide, g
15、iven off by the following acidified solution, is poisonous and desensitizing. Extreme care should therefore be taken in handling the solutions, and all the operations should be carried out in a fume cupboard. 2.4.1 Dissolve11 0.1g of hydrated sodium sulphide(2.2.1) in 100mL of distilled water(2.2.10
16、) in a250mL beaker(2.2.4). 2.4.2 Add, with stirring,6mL of concentrated hydrochloric acid(2.2.2) to a second250mL beaker containing100mL of distilled water(2.2.10). 2.4.3 Transfer50mL of each of the solutions prepared at2.4.1 and2.4.2 into a250mL beaker, stir and cover with a clock glass(2.2.7). 2.5
17、 Procedure Immerse the test specimen in the solution prepared at2.4.3. Cover the beaker with a clock glass, stirring the solution occasionally with a glass rod(2.2.6). After30min immersion, remove the test specimen from the acidified sodium sulphide solution, and wash it thoroughly in distilled wate
18、r. Absorb the surplus water from the test specimen by pressing it between filter papers. Immediately compare the colour of both surfaces of the test specimen with the original sample, and record any change in shade or colour by reference to the grey scale for assessing staining(2.2.5). Expose the te
19、st specimen for24h to the normal laboratory atmosphere, and re-examine it to assess whether any permanent staining has occurred by comparing it with the original sample. Record any contrast between the test specimen and the original sample by reference to the grey scale for assessing staining. Where
20、 necessary, repeat the test to ensure that all colours in a multicoloured sample have been tested. 2.6 Expression of results 2.6.1 No staining. If there is no contrast in shade or colour between the test specimen and the original sample, express the result as “unstained”. 2.6.2 Staining. If there is
21、 any contrast in shade or colour between the test specimen and the original sample, express the result as “stained”, followed by the numerical rating for the contrast by reference to the grey scale for assessing staining. If this lies between two contrasts on the scale, give an intermediate assessme
22、nt, e.g.3-4. 2.6.3 Temporary staining. If there is any staining immediately after removal of the test specimen from the test solution which then disappears after24h exposure to the standard atmosphere for conditioning and testing specified in BS3424-2, express the result as “temporary staining”. 2.7
23、 Test report The test report shall include the following particulars: a) the description of the sample, including details of the number of colours contained;BS3424-19:1989 2 BSI 05-1999 b) whether the test specimen was unstained (see 2.6.1) or stained (see 2.6.2)/temporarily stained (see2.6.3), and
24、if so, the numerical rating for the contrast in shade or colour between the test specimen and the original sample and the colour to which the result applies; c) reference to this method of test, i.e.method22A of BS3424-19; d) details of any deviation from the standard test procedure. 3 Method22B. Co
25、rrosive sulphur test (Silver stain test) 3.1 Principle A test specimen of coated fabric is placed on a polished and degreased piece of assay quality silver foil. The foil and coated fabric are placed superposed inside an oven maintained at70C for30min. After removal from the oven and return to norma
26、l temperature, the silver foil is inspected and staining of the foil is assessed. 3.2 Apparatus and reagents 3.2.1 Two or three pieces of silver foil (see 3.4) assaying at99.9% silver, each measuring at least30mm 30mm. 3.2.2 Jewellers rouge. 3.2.3 Propan-2-ol (isopropyl alcohol) complying with BS159
27、5-1. 3.2.4 Polishing and drying cloth of pharmaceutical grade absorbent material. 3.2.5 Grey scale for assessing staining complying with BS1006:A03. 3.2.6 An oven capable of maintaining a dry atmosphere of70 1 C. 3.2.7 Glass plate measuring30mm 30mm 4mm. 3.2.8 Filter papers each measuring30mm 30mm.
28、3.2.9 Clean glass jar with stopper. 3.3 Test specimen Cut a test specimen measuring25mm 25mm from the sample, but not within50mm of the selvedge. 3.4 Procedure Thoroughly clean and polish both pieces of silver foil(3.2.1) with the jewellers rouge(3.2.2) and isopropyl alcohol(3.2.3). Rub dry with the
29、 polishing and drying material(3.2.4). If double-faced coated fabric is to be tested, three pieces of silver foil will be required to be cleaned and polished. Place one of the cleaned and polished pieces of silver foil in the glass jar(3.2.9) to avoid contamination. Carefully place a specimen of coa
30、ted fabric, coated side down, onto one of the polished pieces of silver foil. Cover the coated fabric with a filter paper(3.2.8), and cover the filter paper with a glass plate(3.2.7). If double-faced coated fabric is to be tested, place the second piece of silver foil on the upper coated surface, an
31、d cover with the filter paper and glass plate. Place the test assembly of coated fabric, foil, filter and glass plate carefully in a horizontal position inside an oven(3.2.6) pre-heated to70 1 C. Remove the test assembly from the oven30min after the oven has regained its temperature of70 1 C. Remove
32、 the coated fabric from the silver foil, and immediately compare the silver foil removed from the oven with the polished silver foil removed from the glass jar, reporting any staining by reference to the grey scale for assessing staining(3.2.5). 3.5 Expression of results 3.5.1 No staining. If there
33、is no contrast in shade or colour between the silver foil removed from the oven and the reference sample, express the result as “unstained”. 3.5.2 Staining. If there is any contrast in shade or colour between the silver foil removed from the oven and the reference sample, express the result as “stai
34、ned”, followed by the numerical rating for the contrast by reference to the grey scale for assessing staining. If this lies between two contrasts on the scale, give an intermediate assessment, e.g.3-4. 3.6 Test report The test report shall include the following particulars: a) the description of the
35、 sample; b) whether the silver foil was unstained (see3.5.1) or stained (see3.5.2), and if so, the numerical rating for the contrast in shade or colour between the silver foil removed from the oven and the reference sample of foil; c) reference to this method of test, i.e.method22B of BS3424-19; d)
36、details of any deviation from the standard test procedure.BS3424-19:1989 BSI 05-1999 3 4 Method22C. Corrosive sulphur test (Copper stain test) 4.1 Principle A cleaned, polished and degreased pure copper sheet is immersed at40C for5h in a test solution of toluene and trimethylpentane together with st
37、rips of a test specimen of coated fabric. The test strips of coated fabric and the copper sheet are then removed, and the copper sheet is compared with a similar one immersed for5h in a clean test solution containing no coated fabric specimen. Staining of the copper sheet immersed with the coated fa
38、bric specimens is assessed against the clean copper sheet and any staining is reported by reference to the grey scale for assessing staining. 4.2 Apparatus and reagents 4.2.1 Two stoppered clean glass vessels of at least200mL capacity. 4.2.2 Stainless steel surgical forceps. 4.2.3 Two pieces of pure
39、 copper sheet each measuring13mm 75mm. 4.2.4 Jewellers rouge. 4.2.5 Polishing and drying cloth of pharmaceutical grade absorbent material. 4.2.6 Propan-2-ol (isopropyl alcohol) complying with BS1595-1. 4.2.7 Sulphur-free test fluid mixture of 35 % toluene complying with BS 135, BS 458, BS 805 and 65
40、% 2,2,4-terimethylpentane. 4.2.8 Means of maintaining an atmosphere of40 1 C. 4.2.9 Grey scale for assessing staining complying with BS1006:A03. 4.3 Test specimens Cut a test specimen with a mass of5 0.5g into pieces measuring approximately3mm 3mm. 4.4 Procedure Thoroughly clean and polish both copp
41、er sheets(4.2.3) using a paste of jewellers rouge(4.2.4) and isopropyl alcohol(4.2.6) and the polishing cloth(4.2.5). Continue rubbing the copper sheets with successive clean polishing cloths until a clean pad remains unsoiled. Wash both copper sheets in isopropyl alcohol, remove them using the forc
42、eps(4.2.2), and allow to dry. Do not handle the copper sheets other than with the forceps. Completely immerse one of the copper sheets together with the pieces of test specimen (see4.3) in approximately100mL of the test fluid(4.2.7) in the first glass vessel(4.2.1), and maintain the mixture at40 1 C
43、 for5h. Simultaneously, immerse the second copper sheet in approximately100mL of the test fluid in the second glass vessel at40 1 C for5h. Using the forceps, remove the copper sheet from the glass vessel containing the pieces of test specimen, and wash in isopropyl alcohol. Again using the forceps,
44、remove the copper sheet from the glass vessel containing the uncontaminated test fluid, and wash in fresh isopropyl alcohol. As soon as they are dry, compare the two copper sheets, and report any staining of the one from the glass vessel containing the strips of test specimen by reference to the gre
45、y scale for assessing staining(4.2.9). 4.5 Expression of results 4.5.1 No staining. If there is no contrast in shade or colour between the copper sheet immersed with the pieces of test specimen and the other copper sheet immersed in uncontaminated test fluid, express the result as “unstained”. 4.5.2
46、 Staining. If there is any contrast in shade or colour between the copper sheet immersed with the pieces of test specimen and the other copper sheet immersed in uncontaminated test fluid, express the result as “stained”, followed by the numerical rating for the contrast by reference to the grey scal
47、e for assessing staining. If this lies between two contrasts on the scale, give an intermediate assessment,e.g.34. 4.6 Test report The test report shall include the following particulars: a) the description of the sample; b) whether the copper sheet was unstained (see4.5.1) or stained (see4.5.2), an
48、d if so, the numerical rating for the contrast in shade or colour between the copper sheet immersed with the pieces of test specimen and the other copper sheet immersed in uncontaminated test fluid; c) reference to this method of test, i.e.method22C of BS3424-19; d) details of any deviation from the
49、 standard test procedure.4 blankBS3424-19:1989 BSI 05-1999 Publications referred to BS135,BS458,BS805, Specifications for benzene, xylenes and toluenes. BS1006, Methods of test for colour fastness of textiles and leather A03 Grey scale for assessing staining (including half-step). BS1595, Propan-2-ol (isopropyl alcohol) for industrial use. BS1595-1, Specification for propan-2-ol (isopropyl alcohol). BS3424, Testing coated fabrics. BS3424-0, Foreword and general introduction. BS3424-2:Method 4, Conditioning and selection of test specimens. BS3978, S
