1、BRITISH STANDARD BS 6996:2003 Incorporating Corrigendum No. 1 Mineral oil resistant acrylonitrile-butadiene rubber compounds Specification ICS 83.060 BS 6996:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 18 June 2003 BSI 5 September 20
2、03 The following BSI references relate to the work on this British Standard: Committee reference PRI/54 Draft for comment 02/122019 DC ISBN 0 580 41847 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted to PRI/54, Vulcanized rubber compounds, up
3、on which the following bodies were represented: British Rubber Manufacturers Assn Chemical Industries Association Ministry of Defence RAPRA Technology Ltd Tun Abdul Razak Research Centre Amendments issued since publication Amd. No. Date Comment 14593 Corrigendum No. 1 5 September 2003 Changes to Tab
4、le 2BS 6996:2003 BSI 5 September 2003 i Contents Page Committees responsible Inside front cover Foreword ii 1S c o p e 1 2 Normative references 1 3 Classification 1 4C o m p o s i t i o n 2 5 Preparation of test sheet 2 6 Physical properties of the vulcanized test sheet 2 7M a r k i n g 2 Annex A (i
5、nformative) Guidance for the preparation and testing of rubber products 4 Bibliography 5 Table 1 Compound classification 1 Table 2 Requirements for physical properties of two-thickness test sheets 3BS 6996:2003 ii BSI 5 September 2003 Foreword This British Standard has been prepared under the direct
6、ion of PRI/54, Vulcanized rubber compounds. It supersedes BS 6996:1989, which is withdrawn. It specifies requirements for acrylonitrile-butadiene rubber compounds for use where resistance to mineral oils without excessive shrinkage is of prime importance. One technical change has been made, namely t
7、he inclusion of the larger type 1 dumbbell of BS 903-A2 as an alternative to the type 2 dumbbell for the measurement of tensile strength and elongation at break (Table 2). The determination of hardness change after accelerated ageing has also been brought into line with this other standard, i.e. the
8、 use of two 2.00 mm thick plies. This edition otherwise comprises an editorial revision of the 1989 standard, in which the presentation has been changed to align the text with other British Standards in the group. Requirements for general purpose acrylonitrile-butadiene rubber compounds are given in
9、 BS 2751. Other British Standards in this group for rubber compounds are as follows: BS 1154, Natural rubber compounds Specification. BS 1155, Natural rubber compounds for extrusion Specification. BS 2752, Chloroprene rubber compounds Specification. BS 3227, Butyl rubber compounds (including halobut
10、yl compounds) Specification. BS 6014, Ethylene propylene rubber compounds Specification. The following British Standards are also relevant to this standard. BS 3558, Glossary of rubber terms. BS 3734-1, Rubber Tolerances for products Part 1: Dimensional tolerances. This publication does not purport
11、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. Summary of pages This document comprises a front cover, an inside front cover, pages i to ii, pages
12、1 to 5 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.BS 6996:2003 BSI 5 September 2003 1 1 Scope This British Standard specifies compositional and physical property requirements for six acrylonitrile-butadiene rubber compounds resis
13、tant to mineral oil and of hardness range 40 IRHD to 90 IRHD. These compounds are intended for the manufacture of items in the form of extrusions, mouldings and sheet, and for items cut or punched from sheet, in which resistance to mineral oils without excessive shrinkage is a necessary property, an
14、d where some stiffening of the harder grades at temperatures below 20 C can be tolerated. NOTE Ozone, which is naturally present in the atmosphere, can cause unprotected nitrile rubber to crack when it is strained, and this can often lead to failure of the part. The nitrile rubber compounds specifie
15、d 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 whether ozone resistance is required for their application. There is currently no British Standard f
16、or ozone resistant nitrile rubber compounds. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the reference cited applies. For undated references, the latest edition of the referenced document (including any
17、amendments). BS 903-A1:1996, Physical testing of rubber Part A1: Determination of density. BS 903-A2:1995, Physical testing of rubber Part A2: Method for determination of tensile stressstrain properties. BS 903-A6:1992, Physical testing of rubber Part A6: Method for determination of compression set
18、at ambient, elevated or low temperatures. BS 903-A19:1998, Physical testing of rubber Part A19: Rubber, vulcanized or thermoplastic Accelerated ageing and heat resistance tests. BS 903-A26:1995, Physical testing of rubber Part A26: Method for Determination of hardness (hardness between 10 IRHD and 1
19、00 IRHD). BS 903-A37:1997, Physical testing of rubber Part A37: Determination of adhesion to and corrosion of metals. BS ISO 1817:1999, Rubber vulcanized Determination of the effect of liquids. 3 Classification Compounds shall be classified according to their vulcanized hardness and designated by gr
20、ade as shown in Table 1. Table 1 Compound classification Grade designation Hardness after vulcanization (IRHD) BO40 BO50 BO60 BO70 BO80 BO90 40 4 +5 50 4 +5 60 4 +5 70 4 +5 80 4 +5 90 4 +5BS 6996:2003 2 BSI 5 September 2003 4 Composition The compounds shall be based on acrylonitrile-butadiene copoly
21、mer reinforced only with carbon black, vulcanized with sulfur/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 reclaimed or ground vul
22、canized rubber shall be used. Natural rubber may be used to produce a “building tack” if necessary but 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 sheets or sample item
23、s, as practicable, to verify that the composition of the mix conforms to this clause. The methods described in BS 4181-1, BS 5923-2, BS 7164-2.2, BS 7164-3, BS 7164-5, BS 7164-7.1, BS 7164-13, BS 7164-14, BS 7164-21 and BS 7164-22.1 should be used where relevant. 5 Preparation of test sheet From eac
24、h batch of rubber mix, a two-thickness test sheet of the following dimensions shall be prepared for testing for compliance with this standard. 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
25、 shall be (2.00 0.15) mm thick. The thicker sections of the sheet shall not be additionally vulcanized. If part of the 6.3 mm section is moulded in the form of cylindrical buttons, complying with the requirements of the type B test piece defined in BS 903-A6 for the purpose of compression set tests,
26、 the mould cavities shall be individually charged with pellets and not by the flow of the 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. 6 Physical properties of the vulcanized test she
27、et Test pieces cut from the test sheet (see Clause 4) shall comply with the relevant requirements given in Table 2 when tested by the methods specified therein. NOTE Guidance for the preparation and testing of rubber products is given in Annex A. 7 Marking The compound, as sheet or items, shall be a
28、ccompanied by the following information (see also BS ISO 2230): a) number and date of this British Standard, i.e. BS 6996:2003 1) , and grade designation; b) quarter and year of cure; c) manufacturers identity or trade mark; d) manufacturers batch number or similar means of production identity. 1) M
29、arking BS 6996:2003 on or in relation to a product represents a manufacturers declaration of conformity, 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 is therefore solely the responsibility of the person making the
30、 claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable.BS 6996:2003 BSI 5 September 2003 3 Table 2 Requirements for physical properties of two-thickness test sheets Physical property Requirement for grade designation Test method in
31、BS 903 parts or BS ISO series and type of test piece where appropriate BO40 BO50 BO60 BO70 BO80 BO90 Hardness after vulcanization (IRHD) Part A26, method N, two plies, 6.30 mm and 2.00 mm, with the thicker ply on top Density (Mg/m 3 ) Agreed value 0.02 a Part A1, method A Minimum tensile strength (M
32、Pa) 7.0 7.5 8.5 12.5 12.5 12.5 Part A2, type 1 or type 2 dumbbells Minimum elongation at break (%) 600 450 400 250 150 100 Maximum compression set (%) 30 25 20 20 20 20 Part A6, type B test piece Lubricated, h at (100 1) C Resistance to liquids Volume change (%) BS ISO 1817, h at (100 1) C after imm
33、ersion in: a ) o i l n o . 1 5 5 5 4 4 4 b) oil no. 3 +25 +25 +20 +20 +15 +15 0 0 0 0 0 0 Resistance to accelerated ageing Part A19, air-oven method A, h, (100 1) C Change in hardness degrees (IRHD) 0 +10 0 +10 0 +10 0 +10 0 +10 0 +10 Part A26, method N, measurement before and 2 plies after ageing o
34、n the same each 2.00 mm thick Maximum change in tensile strength 10 10 10 10 10 10 Part A2, type 1 or type 2 dumbbells (% of original value) Maximum change in elongation at break 35 35 35 35 35 35 (% of original value) Resistance to low temperature. Temperature in C at which the stiffness shall not
35、exceed 70 MPa 30 25 25 20 15 10 Part A13 Adhesion to and corrosion of metals There shall be no corrosion or pitting of the metals and the vulcanizates shall not adhere to the metal surfaces or show any sign of liquid exudation. Discoloration of the metal surfaces shall not be considered cause for re
36、jection Part A37, using carbon steel and copper, (168 2) h, (70 1) C a No values are specified for density, but it is recommended that a value be established for each composition. This may provide a useful check when a series of batches of the same composition has to be tested for compliance with th
37、is British Standard. 40 4 +5 50 4 +5 60 4 +5 70 4 +5 80 4 +5 90 4 +5 24 2 0 72 2 0 72 2 0 BS 6996:2003 4 BSI 5 September 2003 Annex A (informative) Guidance for the preparation and testing of rubber products This British Standard specifies requirements for the rubber compounds when tested using a pr
38、ess-cured sample sheet. Where manufactured articles are to be tested, the shape and size can prevent the preparation of some or all test pieces. In this case, agreement between manufacturer and purchaser should be sought on the procedure to verify compliance of the manufactured article. Where standa
39、rd test pieces can be prepared from the articles they may be used for quality control tests. Finished rubber items should be free from surface imperfections, voids, inclusions, flow marks, moulding faults and defects which would impair satisfactory performance and should show minimal accelerator blo
40、om. Finished rubber items should be stored in accordance with BS ISO 2230.BS 6996:2003 BSI 5 September 2003 5 Bibliography BS 1154:2003, Specification for natural rubber compounds. 2) BS 1155:2003, Specification for natural rubber compounds for extrusion. 2) BS 2751:2001, Specification for general p
41、urpose acrylonitrile-butadiene rubber compounds. 2) BS 2752:2003, Specification for chloroprene rubber compounds. 2) BS 3227:2003, Specification for butyl rubber compounds (including halobutyl compounds). 2) BS 3558-1:1997, Glossary of rubber terms Part 1: International terms. 2) BS 3558-2:2001, Glo
42、ssary of rubber terms Part 2: Additional British terms. 2) BS 3734-1:1997, Rubber Tolerances for products Part 1: Dimensional tolerances. 2) BS 4181-1:1985, Identification of rubbers by infra-red spectrometry Part 1: Method for identification of hydrocarbon, chloroprene, nitrile and chlorosulphonate
43、d polyethylene rubbers. BS 5923-2:1980, Methods for chemical analysis of rubber Part 2: EDTA titrimetric method for determination of zinc content of rubber products. BS 6014:2003, Specification for ethylene propylene rubber compounds. 2) BS 7164-2.2:1990, Chemical tests for raw and vulcanized rubber
44、 Part 2.2: Sample preparation Vulcanized 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, Chemica
45、l tests for raw and vulcanized rubber Part 7.1: Methods for determination of polymer content 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 rubb
46、er Part 14: Methods for determination of carbon black content. BS 7164-21:1996, Chemical tests for raw and vulcanized rubber Part 21: Determination of nitrogen content. BS 7164-22.1:1994, Chemical tests for raw and vulcanized rubber Part 22.1: Determination of chlorine content Parr bomb method. BS I
47、SO 2230:2002, Rubber products Guidelines for storage. 2) Referred to in the foreword only.BS 6996:2003 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in
48、Europe and at the international level. It is incorporated by Royal Charter. 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 quality of our p
49、roducts and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: +44 (0)20 8996 9000. Fax: +44 (0)20 8996 7400. BSI offers members an i
