1、BRITISH STANDARD BS 6564-3: 1990 Polytetrafluoroethylene (PTFE) materials and products Part 3: Specification for E glass fibre filled polytetrafluoroethylene UDC 678.743.41:678.067.5:678.0294:620.1:006.3/.8BS6564-3:1990 This British Standard, having been prepared under the direction of the Plastics
2、Standards Policy Committee, was published under the authority of the Board of BSI and comes into effect on 28 February 1990 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference PLM/34 Draft for comment 88/36032 DC ISBN 0 580 18032 8 Committees responsible
3、 for this British Standard The preparation of this British Standard was entrusted by the Plastics Standards Policy Committee (PLM/-) to Technical Committee PLM/34, upon which the following bodies were represented: British Fluoropolymer Processors Group British Plastics Federation British Valve and A
4、ctuator Manufacturers Association Engineering Equipment and Materials Users Association Ministry of Defence Amendments issued since publication Amd. No. Date of issue CommentsBS6564-3:1990 BSI 07-1999 i Contents Page Committees responsible Inside front cover Foreword ii 0 Introduction 1 1 Scope 1 2
5、Definition 1 3 Designation 1 4 Composition and appearance 1 5 Performance and physical properties 1 6 Dimensional tolerance 3 7 Sampling 3 8 Marking 4 Appendix A Information to be agreed between the purchaser and the supplier 5 Appendix B Method for determining compression modulus 5 Table 1 Forms, g
6、rades, subgrades and types covered by BS 6465-3 2 Table 2 Performance and physical properties 2 Table 3 Tolerance on nominal outside diameter 3 Table 4 Tolerance on thickness of sheet 3 Table 5 Tolerance on nominal width and nominal thickness of veneered tape 3 Publications referred to Inside back c
7、overBS6564-3:1990 ii BSI 07-1999 Foreword This Part of BS6564 has been prepared under the direction of the Plastics Standards Policy Committee. This Part provides the composition and physical property requirements for E glass fibre filled polytetrafluoroethylene fabricated products. The style of the
8、 designation follows closely the designation introduced into BS6564-2 for unfilled products. In this Part of BS6564, the requirements are specified in three grades of product which are designated grade G5, G15 and G25 containing a nominal 5%, 15% and 25% of E glass fibre filler. Requirements are als
9、o specified for three subgrades of product which are designated subgrade A1, subgrade A and subgrade B (subgrade A1 denoting the highest quality and subgrade B the lowest quality specified in this Part of BS6564). The products are also designated as being one of two types, depending on the degree of
10、 dimensional stability: type 1 products are designated as those which meet the requirements for dimensional stability given inTable 2; type 2 products, usually products which are described as “as fabricated”, do not necessarily meet these requirements. This Part of BS6564 does not include any detail
11、ed information on machining tolerances but it should be noted that some difficulty in achieving closely controlled dimensions may be experienced when working with PTFE. The British Fluoropolymer Processors Association has published a document 1)which gives guidance on this subject. CAUTION. Care sho
12、uld be exercised when specifying extruded materials for machining into components which are required to conform to close tolerances as the release of locked-in stress may occur in the components after machining. It is intended to introduce a wear test in the future when a satisfactory test has been
13、identified. Various requirements and methods of test, which are not specified in this Part of BS6564 but which may need to be agreed between the purchaser and the supplier, are listed inAppendix A. Other Parts and Sections of BS6564 are as follows. Part 1: Polytetrafluoroethylene powders for mouldin
14、g and extrusion; Section 1.1: Specification; Section 1.2: Method of specifying; Part 2: Specification for fabricated unfilled polytetrafluoroethylene products. NOTE 1In Part 2 of this standard, the first element of the designation for fabricated unfilled PTFE products will be the letter “U”. The rem
15、ainder of the designation will correspond to that specified for glass fibre filled PTFE fabricated products in this Part of BS6564 (see clause2). WARNING. It is essential that tobacco products are kept well away from areas where they could be contaminated by PTFE dust. The smoking of tobacco product
16、s contaminated by PTFE can result in a temporary, flu-like condition, known as “polymer fume fever”. This condition is the only adverse effect observed in humans to date. The symptoms do not ordinarily occur until several hours after inhalation of the fumes and pass off within 36 h to 48 h even in t
17、he absence of treatment. Observations indicate that these attacks have no lasting effects and that the effects are not cumulative. 1) Publication No. 284/1, Code of practice for machining tolerances for components machined from PTFE, which may be purchased from the British Fluoropolymer Processors A
18、ssociation,5Belgrave Square, London SW1X 8PH.BS6564-3:1990 BSI 07-1999 iii When heated above 260 C, PTFE will begin to degrade and the rate of degradation will increase with increasing temperature. The gases produced during degradation will vary according to the temperature and other conditions but
19、will invariably contain toxic components and good ventilation is therefore essential. NOTE 2It is strongly recommended that users of this standard refer to BFPA Publication No. 254/1 2)for further information. A British Standard does not purport to include all the necessary provisions of a contract.
20、 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, pages i to iv, pages 1 to 6, an inside back cover an
21、d 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 front cover. 2) Publication No. 254/1, Industrial health and safety for PTFE polymers, which may be purchased from the British Flu
22、oropolymer Processors Association, 5 Belgrave Square, London SW1X 8PH.iv blankBS6564-3:1990 BSI 07-1999 1 0 Introduction Fabricated unfilled polytetrafluoroethylene (PTFE), whilst having many advantageous properties making it a material of wide applicability, suffers from relatively poor resistance
23、to wear and high deformation when subjected to compressive loads. These deficiencies may be improved by the incorporation of fillers such as glass fibre. In order that such enhancements may be realized, up to25%(m/m) of E glass fibre filler, milled typically to an aspect ratio of 10:1 (length : diam
24、eter), is intimately compunded into the PTFE before fabrication. Whilst the addition of such amounts of E glass fibre filler gives improved wear, performance and resistance to compressive forces, care should be taken as other properties may be adversely affected, e.g. the resistance to attack by cer
25、tain chemicals may deteriorate, the coefficient of friction may rise and the electrical properties may be modified (particularly under conditions of high ambient humidity). 1 Scope This Part of BS6564 specifies requirements for fabricated E glass fibre filled polytetrafluoroethylene (PTFE) products
26、which may occur in several forms, available in the grades, subgrades and types as indicated inTable 1. NOTE 1E glass is defined in BS3447 as “a glass containing not more than 1 % of alkali (calculated as Na 2 O) and used for the manufacture of glass fibres”. NOTE 2The titles of the publications refe
27、rred to in this standard are listed on the inside back cover. 2 Definition For the purpose of this British Standard the following definition applies. product batch a group of mouldings or extrusions produced from the same batch of powder, subjected to the same fabrication techniques and conditions a
28、nd to the same thermal regime 3 Designation Products complying with this Part of BS6564 shall be designated by a code containing the following elements. a) A letter followed by a number denoting the grade of the material. Fibre glass filled PTFE products are denoted by the letter G followed by a num
29、ber denoting the percentage nominal glass fibre content 3) . b) A letter, or a combination of letters and numbers, denoting the subgrade of the product, i.e. A1, A, B (as specified inTable 1). c) An oblique stroke followed by a number denoting the type of product, i.e. 1 or 2. NOTEType 1 products ar
30、e designated as those which meet the requirements for dimensional stability given inTable 2; type 2 products, usually products which are described as “as fabricated”, do not necessarily meet these requirements. Example. G 15 A1/1 (grade G 15, subgrade A1, type 1). 4 Composition and appearance The pr
31、oducts shall be manufactured from E glass filled polytetrafluoroethylene which contains no other additives except pigments. The use of reprocessed material shall be permissible providing that products containing reprocessed material meet the requirements of this standard (see notes 1 to 3 andAppendi
32、x A). The addition of up to 1.5 % (m/m) of pigment shall be permitted during the manufacture of an item, for the purposes of identification or decoration. The presence of added pigment shall be reported in all documentation relating to a particular product. NOTE 1The colour of the unpigmented produc
33、ts varies from semi-translucent white to mottled grey. Colours outside this range will normally be obtained by pigmentation. NOTE 2The presence of pigments may affect some properties of the material, e.g. chemical resistance and electrical properties, and it is advisable for the purchaser and the su
34、pplier to agree the type, grade and quantity of pigment to be used (seeAppendix A). NOTE 3Due to the nature of some manufacturing methods, accurate reproduction of colour in pigmented items is difficult and some variation may be exacerbated by high E glass filler content. NOTE 4Products are normally
35、 available free from surface defects or inclusions. 5 Performance and physical properties The products shall comply with the appropriate requirements given inTable 2. To comply with the requirements for tensile strength and elongation at break, the minimum mean values, determined by the method speci
36、fied, shall be as specified inTable 2. If any individual result for tensile strength or elongation at break is below the compliance limit specified inTable 2 and more than 15 % below the mean value, a further set of test specimens shall be tested and if the second set of results fail to meet the com
37、pliance limits specified, the material shall be deemed not to comply with this Part of BS6564. 3) See note 1 in foreword.BS6564-3:1990 2 BSI 07-1999 Table 1 Forms, grades, subgrades and types covered by BS 6564-3 Table 2 Performance and physical properties Form Grade Subgrade Type Moulded basic shap
38、es, moulded or extruded rod, moulded or extruded tube and moulded sheet G5 A1, A, B Types 1 and 2 G15 A1, A, B Types 1 and 2 G25 A1, A, B Types 1 and 2 Veneered tape G5 A1, A, B Type 2 only G15 A1, A, B Type 2 only G25 A1, A, B Type 2 only Requirement Applicable to Method Compliance criteria Filler
39、content SubgradeA1 SubgradeA SubgradeB % MPa MPa MPa Tensile strength All products BS 2782: Method327A 5 15 25 16 15 14 15 14 12 14 13 11 % % % Elongation at break All products BS 2782: Method327A 5 15 25 230 200 160 210 180 140 190 160 120 g/cm 3 Density at 23 2 C All products BS 2782: Method620A o
40、r Method 620D 5 15 25 2.19 0.04 2.21 0.04 2.23 0.04 Resistance to heat All products Appendix B of BS6564-2:1985 All grades The material shall show no signs of melting and the loss in mass shall not exceed 0.5 % MPa MPa MPa Compressive modulus Subgrades A1 and A Appendix B 5 15 25 475 550 750 475 550
41、 750 Dimensional stability All type 1 products except tube and veneered tape Appendix C of BS6564-2:1985 All grades The maximum change shall not exceed 0.5 % Type 1 tube Appendix D of BS6564-2:1985 All grades The maximum changes in length and diameter shall each not exceed 0.5 % Geometric stability
42、Type 1 tube Appendix D of BS6564-2:1985 All grades The maximum change shall not exceed where D is the nominal external diameter T is the nominal wall thickness % (m/m) Filler content All products Appendix A of BS6564-1.1:1989 5 1 (i.e. 4 to 6) 15 2 (i.e. 13 to 17) 25 2 (i.e. 23 to 27) D 4T -%BS6564-
43、3:1990 BSI 07-1999 3 6 Dimensional tolerances 6.1 General Dimensions shall be measured at 23 2 C. NOTEFor moulded basic shapes, seeAppendix A. 6.2 Rod and tube The tolerance on the nominal outside diameter shall be as given inTable 3. Table 3 Tolerance on nominal outside diameter The actual inside d
44、iameter (bore) of tube shall at no point be greater than the nominal inside diameter. NOTE 1Minimum tolerances on inside diameters of tube are not specified because these are dependent on whether the tube is to be machined or not and on the intended use. For finished tube, after machining if appropr
45、iate, the eccentricity of the bore shall not exceed 4.0 % of the nominal inside diameter (FIM 4)of 8 %). For tube supplied as machining stock, the tube shall be capable of being machined concentrically to the required dimensions. NOTE 2Moulded rod of diameter greater than 50mm, and moulded tube of o
46、utside diameter greater than 50mm and wall thickness greater than 15mm, may be considered as moulded basic shapes (seeAppendix A). 6.3 Sheet The tolerances on both the width and the length of the sheet shall be 0mm, +6.5mm. The tolerance on the thickness of the sheet shall be as given inTable 4. Tab
47、le 4 Tolerance on thickness of sheet 6.4 Veneered tape The tolerance on the nominal width and nominal thickness of the tape shall be as given inTable 5. Table 5 Tolerance on nominal width and nominal thickness of veneered tape 7 Sampling A separate sample shall be taken to represent each product bat
48、ch (see clause2) and shall be of sufficient size to enable the required test specimens to be prepared from it. In the case of moulded shapes which are too small to produce the required test specimens or too large to be sampled and tested without loss of more than 1 % of the batch of product, it shal
49、l be permissible to produce a test moulding. Such a test moulding shall be produced from the same batch of powder, and shall be subjected to the same moulding conditions and the same thermal regime as the product batch it represents. The test specimens for the determination of dimensional or geometric stabilities (for type 1 products) shall be cut from their actual batch and not from a specially moulded test sample. NOTEFor sampling on continuous production, seeAppendix A. Nominal outside diameter Tolerance mm
