BS ISO 35-2004 Natural rubber latex concentrate - Determination of mechanical stability《浓缩天然胶乳 机械稳定性的测定》.pdf

1、BRITISH STANDARDBS ISO 35:2004IncorporatingAmendment No. 1Natural rubber latex concentrate Determination of mechanical stabilityICS 83.040.10g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g6

2、0g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO 35:2004This British Standard was published under the authority of the Standards Policy and Strategy Committee on 3 March 2004 BSI 2006ISBN 0 580 43529 6National forewordThis British Standard reproduces verbatim ISO 35:2004, including amendment 1:2006,

3、and implements it as the UK national standard. It supersedes BS 6057-3.1:1996 which is withdrawn.The start and finish of text introduced or altered by ISO amendment is indicated in the text by tags . Tags indicating changes to ISO text carry the number of the ISO amendment. For example, text altered

4、 by ISO amendment 1 is indicated by .The UK participation in its preparation was entrusted to Technical Committee PRI/50, Rubber-raw, natural and synthetic, including latex and carbon black, which has the responsibility to: A list of organizations represented on this committee can be obtained on req

5、uest to its secretary.Cross-referencesThe British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Cat

6、alogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand t

7、he text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cov

8、er, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 5 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments16246 28 April 2006 See national forewordINTERNATIONAL

9、STANDARDISO35Fifth edition2004-02-15Reference numberISO 35:2004(E)Natural rubber latex concentrate Determination of mechanical stabilityConcentr de latex de caoutchouc naturel Dtermination de la stabilit mcaniqueBS ISO 35:2004iiiiiContents Page1 Scope 12 Normative references 13 Terms and definitions

10、 14 Principle 25 Reagents . 26 Apparatus . 27 Sampling . 38 Procedure . 39 Expression of results 410 Precision statement . 411 Test report 5BS ISO 35:2004ivForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies(ISO member bodies). The

11、work of preparing International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for which a technical committee has beenestablished has the right to be represented on that committee. International organizations, governmental andnon-governme

12、ntal, in liaison with ISO, also take part in the work. ISO collaborates closely with the InternationalElectrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main

13、 task of technical committees is to prepare International Standards. Draft International Standardsadopted by the technical committees are circulated to the member bodies for voting. Publication as anInternational Standard requires approval by at least 75 % of the member bodies casting a vote.Attenti

14、on is drawn to the possibility that some of the elements of this document may be the subject of patentrights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 35 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 3,Raw materi

15、als (including latex) for use in the rubber industry.This fifth edition cancels and replaces the fourth edition (ISO 35:1995), Clauses 8 and 9 of which have beentechnically revised. The principal changes are the removal of a number of options for the method of assessingthe end-point and clarificatio

16、n of the manner in which the result is reported.ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member bod

17、y interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrote

18、chnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by

19、 the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rig

20、hts. ISO shall not be held responsible for identifying any or all such patent rights. Amendment 1 to ISO 35:2004 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.Foreword to amendment A1BS ISO

21、 35:20041Natural rubber latex concentrate Determination of mechanical stabilityWARNING Persons using this International Standard should be familiar with normal laboratorypractice. This standard does not purport to address all of the safety problems, if any, associated with itsuse. It is the responsi

22、bility of the user to establish appropriate safety and health practices and toensure compliance with any national regulatory conditions.1ScopeThis International Standard specifies a method for the determination of the mechanical stability of naturalrubber latex concentrate. It is also applicable to

23、prevulcanized natural rubber latex concentrate.The method is not necessarily suitable for latices or prevulcanized latex preserved with potassium hydroxide,latices from natural sources other than Hevea brasiliensis, or for compounded latex or artificial dispersions ofrubber, and it is not applicable

24、 to synthetic rubber latices.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenced document(including any amendments) applies.I

25、SO 123, Rubber latex SamplingISO 124, Latex, rubber Determination of total solids contentISO 125, Natural rubber latex concentrate Determination of alkalinityISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth3 Terms and definitionsFor the purposes of t

26、his document, the following terms and definitions apply.3.1natural rubber latex concentratenatural rubber latex containing ammonia and/or other preservatives, with the exception of potassium hydroxide,and which has been subjected to some process of concentration3.2mechanical stabilitytime, in second

27、s, required to initiate visible flocculation under the specified test conditionsBS ISO 35:2004ISO/TR 9272, Rubber and rubber products Determination of precision for test method standards 2 4PrincipleA test portion of the latex concentrate is diluted to by mass total solids content and stirred at hig

28、h speed.The time required to initiate visible flocculation is recorded, this being regarded as a measure of the mechanicalstability.5ReagentsThe ammonia solutions (5.1 and 5.2) shall be prepared from ammonium hydroxide of recognized analyticalreagent quality and shall be stored in closed containers.

29、Carbonate-free distilled water or water of equivalent purity shall be used for dilution of the latex. Deionized watermay be used for the detection of the end-point.5.1 Ammonia solution containing by mass of ammonia (NH3), for use with latex concentrate havingan alkalinity of at least (with respect t

30、o the latex concentrate).5.2 Ammonia solution containing by mass of ammonia (NH3), for use with latex concentrate havingan alkalinity of less than (with respect to the latex concentrate).6 ApparatusStandard laboratory apparatus, plus the following:6.1 Mechanical stability measuring apparatus,1)consi

31、sting of the items described in 6.1.1 to 6.1.3.6.1.1 Latex container: A flat-bottomed, cylindrical container at least high, with an internal diameter ofand a wall thickness of approximately . The inner surface shall be smooth.A poly(methyl methylacrylate) or glass container is suitable.6.1.2 Stirrin

32、g apparatus, consisting of a vertical stainless-steel shaft of sufficient length to reach the bottomof the latex container (6.1.1) and tapering to approximately in diameter at its lower end, where anexactly centred, horizontal, smooth, stainless-steel disc, in diameter andthick, is attached. The app

33、aratus shall be capable of maintaining a stirring rate ofthroughout a test, at which frequency the shaft shall not run out of true by morethan .6.1.3 Holder, for the latex container (6.1.1). The holding arrangement shall ensure that the latex container isheld securely, that the axis of the rotating

34、shaft is concentric with that of the container and that the bottom of thestirring disc is from the inner surface of the bottom of the latex container.6.2 Large Petri dish, with a diameter not less than and depth not less than . The size of thePetri dish will permit several tests to be carried out in

35、 the same dish.6.3 Pointed rods: Thin rods, of glass or an inert material such as stainless steel, which have been drawn outor machined to a point. The precise dimensions are not important since the function of the rod is to pick up asmall droplet of latex.1) Suitable instruments are available comme

36、rcially, e.g. from Klaxon Signals Ltd., Honey Pot Lane, Stanmore, HA7 1BE,U.K., Telefax +44 (208) 952 6983. This information is given for the convenience of users of this International Standard anddoes not constitute an endorsement by ISO of this product.55 %1,6 %0,30 %0,6 %0,30 %90 mm58 mm 1 mm 2,5

37、 mm6,3 mm20,83 mm 0,03 mm1,57 mm 0,05 mm14 000 rev/min 200 rev/min0,25 mm13 mm 1mm150 mm 20 mmBS ISO 35:200436.4 Means of heating: Use either a water bath, capable of maintaining a temperature of ;or a glass tube, bent to a shape suitable for insertion in the latex concentrate. together with a means

38、 ofcirculating water at a temperature of through the tube.6.5 Wire cloth, of stainless steel, complying with the requirements of ISO 3310-1, with an average aperturewidth of .7 SamplingCarry out sampling in accordance with one of the methods specified in ISO 123.NOTE Mechanical stability may be adve

39、rsely affected by the duration and temperature of storage of the sample.8 Procedure8.1 GeneralCarry out the determination in duplicate within of first opening the sample bottle. If the total solids contentand alkalinity of the latex concentrate are not known, determine them in accordance with ISO 12

40、4 and ISO 125,respectively.NOTE If the concentration of the carbon dioxide in the atmosphere in the vicinity of the mechanical stability measuringapparatus (6.1) is above normal (about by volume), the mechanical stability of the latex will be reduced. This effectmay be pronounced at carbon dioxide c

41、oncentrations as low as by volume. High concentrations of carbon dioxide inthe atmosphere may be caused by the proximity of any apparatus which generates carbon dioxide, such as certain types ofgas or oil heater.8.2 Dilution and stirringDilute of latex concentrate, in a glass beaker, to by mass with

42、 the appropriate ammoniasolution (5.1 or 5.2). Without delay, warm the diluted latex with gentle stirring to to (i.e. slightlyabove the intended test temperature) by one of the means of heating (6.4). Immediately filter the diluted andwarmed latex through the wire cloth (6.5) and weigh of the filter

43、ed latex into the container (6.1.1).Check the temperature of the latex is . Place the container in the holder (6.1.3) and stir the latex,ensuring that the rotational frequency of the stirrer is throughout the test, until theend-point is passed.8.3 Determination of end-pointThe arrival of the end-poi

44、nt is preceded by a marked decrease in the depth of the vortex around the stirringshaft, accompanied by loss of turbulence and a change in the sound of the stirring action.Two methods are permitted for the determination of the end-point. Inexperienced operators should have themethod of determining t

45、he end-point demonstrated to them.a) Palm-of-the-hand method: Determine the end-point by removing a drop of the latex with a clean glass rodat intervals of and gently spreading the sample on the palm of the hand. Take the end-point as the firstappearance of flocculum. Confirm the end-point by the pr

46、esence of an increased amount of flocculum in asample taken after stirring the latex for an additional .70C 10C70C 10C180 m 7,6 m24 h0,03 %0,05 %100 g 55,0 % 0,2 %35C37C80,0 g 0,5 g35C 1C14 000 rev/min 200 rev/min15 s15 sBS ISO 35:20044 b) Dispersibility-in-water method: Take a large Petri dish (6.2

47、) and introduce to of water. Itwill facilitate observation of the end-point if the Petri dish is standing on a dark surface such as black paper.Using a pointed rod (6.3), pick up a small drop of latex and immediately touch the surface of the water withit. If the latex has not started to flocculate,

48、it will disperse within a few seconds to give a milky cloud. Ifflocculation has commenced, the droplet will generally remain on the surface of the water withoutdispersing. If it should start to disperse, then particles of flocculum will be readily apparent to the naked eye.9 Expression of resultsExp

49、ress the mechanical stability time of the latex concentrate as the number of seconds between the start ofstirring and the end-point.Calculate the mean of the two determinations. If the results of the duplicate determinations do not agree towithin of their mean value, the test shall be repeated.100 cm3150 cm35%BS ISO 35:200410 Precision statement 10.1 The precision of this method was determined in accordance with ISO/TR 9272. Refer to this document for terminology and explanations of statistical concepts. 10.2