1、BRITISH STANDARDBS 2751:2001Incorporating Corrigendum No. 1General purpose acrylonitrile-butadiene rubber compounds SpecificationICS 83.060NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS 2751:2001This British Standard, having been prepared under the direction of the Material
2、s and Chemicals Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 29 November 2001 BSI 21 December 2001BS 2751 first published June 1956BS 3222 first published February 1960First revision as BS 2751 and BS 3222 (combined) Februa
3、ry 1976Second revision as BS 2751 and BS 3222 (combined) May 1982Third revision as BS 2751 September 1990Fourth edition November 2001The following BSI references relate to the work on this standard:Committee reference PRI/54Draft for comment 01/120147 DCISBN 0 580 38278 8Committees responsible for t
4、his British StandardThe preparation of this British Standard was entrusted by the Materials and Chemicals Sector Policy and Strategy Committee (I/-) to Technical Committee PRI/54, Vulcanized Rubber Compounds, upon which the following bodies were represented:British Rubber Manufacturers AssociationCh
5、emical Industries AssociationRAPRA Technology Ltd.Tun Abdul Razak Research CentreAmendments issued since publicationAmd. No. Date Comments13623 Corrigendum No.121 December 2001 Corrections to ISBN number and Draft for comment referenceBS 2751:2001 BSI 21 December 2001iContentsPageCommittees responsi
6、ble Inside front coverForeword ii1Scope 12 Normative references 13 Classification 24Compositon 25 Preparation of test sheet 26 Physical properties of the vulcanized test sheet 37Marking 3Annex A (informative) Guidance for the preparation and testing of rubber products 5Bibliography 6Table 1 Compound
7、 classification 2Table 2 Physical properties of two-thickness test sheets 4BS 2751:2001ii BSI 21 December 2001ForewordThis British Standard has been prepared under the direction of the Materials and Chemicals Sector Policy and Strategy Committee. It supersedes BS 2751:1990 which is withdrawn.This ne
8、w edition of BS 2751 incorporates technical changes only. It does not reflect a full review or revision of the standard, which will be undertaken in due course. Technically, new requirements for resistance to accelerated ageing, change in hardness degrees, maximum change in tensile strength and maxi
9、mum change in elongation at break have been included. BS 903-A6 type 1 test piece has been replaced by type B test piece in the present standard.Other British Standards in this group for rubber compounds are as follows.BS 1154:1992, Specification for natural rubber compounds.BS 1155:1992, Specificat
10、ion for natural rubber compounds for extrusion.BS 2752:1990, Specification for chloroprene rubber compounds.BS 3227:1990, Specification for butyl rubber compounds (including halobutyl compounds).BS 6014:1991, Specification for ethylene propylene rubber compounds.BS 6996:1989, Specification for miner
11、al oil resistant acrylonitrile-butadiene rubber compounds.The following British Standards are also relevant to this standard.BS 3558-1:1997, Glossary of rubber terms Part 1: International terms.BS 3558-2:2001, Glossary of rubber terms Part 2: Additional British terms.BS 3734-1:1997, Rubber Tolerance
12、s for products Part 1: Dimensional tolerances.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 obligatio
13、ns.Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 6, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.BS 2751:2001 BSI 21 December 200111 ScopeThis British S
14、tandard specifies compositional and physical property requirements for general purpose acrylonitrile-butadiene rubber compounds of hardness range 40 IRHD to 90 IRHD, designated BA40, BA50, BA60, BA70, BA80, BA90, and for an electrical grade acrylonitrile-butadiene rubber compound, of hardness 60 IRH
15、D, designated E.These compounds are intended for the manufacture of items in the form of extrusions, mouldings, sheet and items cut or punched from sheet in which resistance to certain organic liquids is a necessary property, and where some stiffening of the harder grades at temperatures below G7020
16、 C can be tolerated.NOTE 1 Compounds in the BA series may not have good electrical insulating properties whereas the compound designated E is available with specific electrical properties.NOTE 2 Ozone, which is naturally present in the atmosphere, can cause unprotected nitrile rubber to crack when i
17、t is strained, and this can often lead to failure of the part. The nitrile rubber compounds specified in this standard are not required to be compounded to be resistant to ozone attack and their resistance to ozone is not tested. Potential users should seek technical advice if they are unsure as to
18、whether ozone resistance is required for their application. There is currently no British Standard for ozone resistant nitrile rubber compounds.2 Normative referencesThe following normative documents contain provisions which, through reference in this text, constitute provisions of this British Stan
19、dard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. For undated references, the latest edition of the publication referred to applies.BS 903-A1:1996, Physical testing of rubber Part A1: Determination of density.BS 903-A2:1995, Physical testi
20、ng of rubber Part A2: Method of determination of tensile stress-strain properties.BS 903-A6:1992, Physical testing of rubber Part A6: Method of determination of compression set at ambient, elevated or low temperatures.BS 903-A13:1990, Physical testing of rubber Part A13: Method of determination of s
21、tiffness at low temperature (Gehman test).BS 903-A16:1999, Rubber, vulcanized Determination of the effect of liquids.BS 903-A19:1998, Rubber, vulcanized or thermoplastic Accelerated ageing and heat resistance tests.BS 903:A26:1995, Physical testing of rubber Part A26: Method for determination of har
22、dness (hardness between 10 IRHD and 100 IRHD).BS 903:A37:1997, Physical testing of rubber Part A37: Determination of tendency to adhere to and to corrode metals.BS 903-C1:1991, Methods of testing vulcanized rubber Part C1: Determination of surface resistivity.BS 903-C2:1982, Methods of testing vulca
23、nized rubber Part C2: Determination of volume resistivity.BS 3574, Specification for controlled storage and packaging of vulcanized rubber and rubber products.BS EN 60243-2:2001, Electric strength of insulating materials Test methods Part 2: Additional requirements for tests using direct voltage.BS
24、2751:20012 BSI 21 December 20013 ClassificationCompounds shall be classified according to their vulcanized hardness, in international rubber hardness degrees (IRHD), and designated by grade as shown in Table 1.Table 1 Compound classification4 CompositionThe compounds shall be based on acrylonitrile-
25、butadiene copolymer reinforced only with carbon black, vulcanized with sulphur/organic accelerator, activated with not less than 4 parts per hundred of rubber by mass (p.h.r.) of zinc oxide. At least 2 p.h.r. of an antioxidant shall be incorporated in the mix.No factice or other extender, or reclaim
26、ed or ground vulcanized rubber shall be used. Natural rubber may be used to produce a “building tack” if necessary but it shall not exceed 10 p.h.r.All ingredients of the mix shall be free from grit and extraneous material.NOTE Chemical analysis may be carried out on either two-thickness sample shee
27、ts or sample items, as practicable, to verify that the composition of the mix complies with this clause. The methods described in BS 7164 Parts 2.2, 3, 5, 7.1, 13 and 14; BS 4181 Part 1 and BS 5923 Part 2 should be used where relevant. 5 Preparation of test sheetFrom each batch of rubber mix, a two-
28、thickness test sheet of the following dimensions shall be prepared for testing.The sheet shall be approximately 250 mm square with a thicker section along one side 35 mm to 50 mm wide and 6.30 0.15 mm thick. The remainder of the sheet shall be 2.00 0.15 mm thick. The thicker sections of the sheet sh
29、all not be additionally vulcanized.If part of the 6.3 mm section is moulded in the form of cylindrical buttons complying with the type B test piece defined in BS 903-A6 for the purpose of compression set tests, the mould cavities shall be individually charged with pellets and not by the flow of the
30、excess rubber from the remainder of the mould. The minimum number of buttons moulded shall be nine and they shall be in a group at one end of the 6.3 mm section.Grade designation Hardness after vulcanization (IRHD)BA4040 BA5050 BA6060 BA7070 BA8080 BA9090 E (electrical)60 +54+54+54+54+54+54+54BS 275
31、1:2001 BSI 21 December 200136 Physical properties of the vulcanized test sheetTest pieces cut from the test sheet (see clause 5) shall comply with the relevant requirements given in Table 2 when tested by the methods specified in Table 2.NOTE Guidance for the preparation and testing of rubber produc
32、ts is given in Annex A.7 MarkingThe compound, as sheet or items, shall be accompanied by the following information (see also BS 3574):a) number and date of this British Standard, i.e. BS 2751:20011), and grade designation;b) quarter and year of cure;c) manufacturers identity or trade mark;d) manufac
33、turers batch number or similar means of production identity.1)Marking BS 2751:2001 on or in relation to a product represents a manufacturers declaration of comformity, i.e. a claim by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim
34、is therefore solely the responsibility of the person making the claim. Such a declaration is not to be confused with third party certification, which may also be desirable.BS 2751:20014 BSI 21 December 2001Table 2 Physicalproperties oftwo-thicknesstestsheetsPhysical propertyGradedesignationTestmetho
35、din BS903and typeoftestpiecewhereappropriateBA40BA50BA60BA70BA80BA90EHardnessafter vulcanization(IRHD)40 50 6070 80 9060 PartA26,methodN, two plies,6.30mm and2.00mm, withthethickerplyontopDensity (Mg/m3)Agreedvalue 0.02aPartA1,methodAMinimum tensilestrength(MPa)Minimumelongationatbreak(%)7.06007.545
36、08.540012.525012.515012.51008.5400Part A2,type2dumb-bellsMaximum compressionset(%)30252020202520PartA6,typeBtestpiece,lubricated,24 hat701Gb0CResistancetoliquidsVolume change (%) after immersion inliquidBPartA16,24hat 401 Gb0CResistancetolow temperatureTemperaturein Gb0Catwhich the stiffnessshall no
37、t exceed70MPa30252520151025PartA13, usingethyl alcohol/CO2cooling mediumResistance toaccelerated ageingPartA19,air-ovenmethod A, 168 2h, 70 1Gb0CChangeinhardnessdegrees(IRHD)Part A26,method N,measurement beforeandafter ageingonthe same2 plies each2.00mm thickMaximum changeintensilestrength(%oforigin
38、alvalue)1010101010Part A2,type2dumb-bellsMaximum changeinelongation atbreak (%oforiginalvalue)3535353535Minimum surface resistivity (G37)Minimum volume resistivity (G37Gb7cm)Norequirement5G20Gd71092 Gd7109PartC1PartC2Minimum electricstrength(kV per2.5mm)5BS EN60243-2Adhesiontoand corrosionof metalsT
39、hereshallbe no corrosion orpittingofthe metals, and the vulcanizatesshall not adheretothemetal surfacesorshowany signofliquidexudation.Discolourationofthemetal surfacesshall notbe consideredcause for rejectionPartA37,usingcarbon steel andcopper,168 2 h,70 1 Gb0CaNovalues are specified fordensity,but
40、 it isrecommendedthat a value be establishedforeachcomposition.This mayprovideausefulcheck whena seriesof batchesofthe samecompositionhas to be tested forcompliancewiththis BritishStandard.+54+54+54+54+54+54+54+020+300+300+250+250+250+250+25+020+100+100+100+100+10BS 2751:2001 BSI 21 December 20015An
41、nex A (informative)Guidance for the preparation and testing of rubber productsThis British Standard specifies requirements for the rubber compounds when tested using a press-cured sample sheet. Where manufactured articles are to be tested the shape and size may prevent the preparation of some or all
42、 test pieces. In this case agreement between manufacturer and purchaser should be sought on the procedure to verify compliance of the manufactured article. Where standard test pieces can be prepared from the articles they may be used for quality control tests.Finished rubber items should be free fro
43、m surface imperfections, voids, inclusions, flow marks, moulding faults and defects which would impair satisfactory performance and should show minimal accelerator bloom.Finished rubber items should be stored in accordance with BS 3574.BS 2751:20016 BSI 21 December 2001Bibliography Standards publica
44、tionsBS 1154:1992, Specification for natural rubber compounds.BS 1155:1992, Specification for natural rubber compounds for extrusion.BS 2752:1990, Specification for chloroprene rubber compounds.BS 3227:1990, Specification for butyl rubber compounds (including halobutyl compounds).BS 3558-1:1997, Glo
45、ssary of rubber terms Part 1: International terms.BS 3558-2:2001, Glossary of rubber terms Part 2: Additional British terms.BS 3574, Specification for the controlled storage and packaging of vulcanized rubber and rubber products.BS 3734-1:1997, Rubber Tolerances for products Part 1: Dimensional tole
46、rances.BS 4181-1:1985, Identification of rubbers by infra-red spectrometry Part 1: Method for identification of hydrocarbon, chloroprene, nitrile and chlorosulphonated polyethylene rubbers.BS 5923-2:1980, Methods for chemical analysis of rubber Part 2: EDTA titrimetric method for determination of zi
47、nc content of rubber products.BS 6014:1991, Specification for ethylene propylene rubber compounds.BS 6996:1989, Specification for mineral oil resistant acrylonitrile-butadiene rubber compounds.BS 7164-2.2:1990, Chemical tests for raw and vulcanized rubber Part 2: Sample preparation Section 2.2: Vulc
48、anized rubber.BS 7164-3:1992, Chemical tests for raw and vulcanized rubber Part 3: Methods for determination of solvent extract.BS 7164-5:1991, Chemical tests for raw and vulcanized rubber Part 5: Methods for determination of ash content.BS 7164-7.1:1990, Chemical tests for raw and vulcanized rubber
49、 Part 7: Methods for determination of polymer content Section 7.1: Polyisoprene content.BS 7164-13:1994, Chemical tests for raw and vulcanized rubber Part 13: Method for determination of total hydrocarbon content.BS 7164-14:1996, Chemical tests for raw and vulcanized rubber Part 14: Methods for determination of carbon black content.blankBS 2751:2001BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent nationa
