1、BRITISH STANDARD BS 3241:1960 Incorporating Amendment No. 1 Specification for Toughened polystyrene for sheet extrusionBS3241:1960 This British Standard, having been approved by the Plastics Industry Standards Committee and endorsed by the Chairman ofthe Chemical Divisional Council, was published un
2、dertheauthority of the GeneralCouncil on 8 April 1960 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PLC/6 Draft for comment A(PLC) 1135 ISBN 0 580 03005 9 Co-operating organizations The Plastics Industry Standards Committee, under whose supervision
3、 this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty Board of Trade British Electrical and Allied Industries Research Association* British Electrical and Allied Manufacturers Association* Bri
4、tish Plastics Federation* D.S.I.R. Building Research Station Electronic Engineering Association Ministry of Aviation* Oil Companies Materials Association Plastics Institute* Post Office* Royal Institute of British Architects The Government departments and scientific and industrial organizations mark
5、ed with an asterisk in the above list together with the following were directly represented on the Committee entrusted with the preparation of this British Standard: National Physical Laboratory (D.S.I.R.) Telecommunication Engineering and Manufacturing Association Amendments issued since publicatio
6、n Amd. No. Date of issue Comments 4132 April 1961 Indicated by a sideline in the marginBS3241:1960 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Impact strength 1 3 Softening point 1 4 Tensile strength and elongation 1 5 Moisture content 1 6 Volati
7、le matter 1 7 Sieve analysis 1 8 Deflection under load 1 9 Colour fastness to light 1 10 Colour stability to heat 1 11 Marking 1 Appendix A Preparation of moulded test sheet 2 Appendix B Method of determining impact strength 2 Appendix C Method of determining tensile strength and elongation at break
8、 2 Appendix D Method of determining moisture content 2 Appendix E Method of determining colour stability to heat 2 Figure 1 Mould 3BS3241:1960 ii BSI 12-1999 Foreword This standard makes reference to the following British Standards: BS 350, Conversion factors and tables. BS 410, Test sieves. BS 2662
9、, Grey scale for assessing change in colour. BS 2782, Methods of testing plastics. This British Standard has been prepared under the authority of the Plastics Industry Standards Committee. It covers toughened polystyrene granules suitable for the manufacture of sheet by an extrusion process. The Bri
10、tish Standard includes tests that have been developed to provide basic data for the control of quality of the material rather than to give information on the properties of extruded sheet. To facilitate the laboratory preparation of specimens the mechanical tests are performed on compression moulding
11、s and not extruded sheet. Certain optional requirements are also included. NOTEWhere metric equivalents are stated the figures in British units are to be regarded as the standard. The metric conversions axe approximate. More accurate Conversions should be based on the tables in BS350, “Conversion fa
12、ctors and tables”. 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. Summary of pages This
13、document comprises a front cover, an inside front cover, pages i and ii, pages1 to 3 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 front cover.BS3241:1960 BSI 12-1999 1 1 Sco
14、pe This British Standard covers the basic requirements for toughened polystyrene in the form of granules for sheet extrusion consisting of thermoplastic polymers or copolymers of styrene and suitable additives. 2 Impact strength When determined by the method described inAppendix B the impact strengt
15、h shall be not less than0.75ft lb (0.1kgm). 3 Softening point When determined by Method102C of BS2782-1 1) , on specimens cut from moulded sheet prepared as inAppendix A, the softening point shall be not less than80 C. NOTEThe softening point determined by this method is merely the temperature at wh
16、ich the specimen reaches a defined deformation under the applied load. Although an increase in the softening point of the granules used in the manufacture of sheet normally raises the temperature at which that sheet or articles formed from it can be used without distortion, the actual maximum temper
17、ature of use is generally lower than the measured softening point and is controlled to a considerable extent by other factors such as stresses set up during extrusion and subsequent fabrication of the extruded sheet. 4 Tensile strength and elongation When determined by the method described inAppendi
18、x C, the tensile strength and the elongation at break shall be not less than2500lb/sq in (176kg/cm 2 ) and15per cent respectively. 5 Moisture content When determined by the method described inAppendix D the moisture content at the time of despatch shall be not more than0.15per cent. NOTEMaterial com
19、plying with this Clause is not necessarily suitable for extrusion without pre-drying. 6 Volatile matter When determined by Method107A of BS2782-1 1) , the volatile matter shall be not greater than3.0per cent. 7 Sieve analysis None of the granules shall be retained on a ) in(9.5mm) BS test sieve 2)an
20、d not more than 0.1 per cent shall pass through22mesh (0.7mm) BS test sieve. 8 Deflection under load When so specified, the deflection under load shall be as agreed between the purchaser and the supplier and shall be determined by Method309A of BS2782-3 3) , on specimens cut from moulded sheet prepa
21、red as inAppendix A. 9 Colour fastness to light When so specified, the limits for colour fastness to light shall be as agreed between the purchaser and the supplier and shall be determined by Method507A or 507B of BS2782-5 4) , on specimens cut from moulded sheet prepared as inAppendix A. 10 Colour
22、stability to heat When so specified, the colour stability to heat shall be as agreed between the purchaser and the supplier, and shall be determined by the method described inAppendix E. 11 Marking Material complying with this British Standard shall have the containers marked with: 1) Suppliers iden
23、tification 2) The number of this British Standard, i.e.BS3241. NOTEThe mark BS3241 on the product is an indication that the goods purport to comply with the requirements of this British Standard. The British Standards Institution is the owner of the registered certification trade-mark shown below. T
24、he presence of this certification mark on a product is an additional and independent assurance that the product does comply with the requirements of the relevant British Standard. This certification mark may be used by the manufacturer only under licence from the BSI, and particulars of the conditio
25、ns under which licences are granted may be obtained from the Director, the British Standards institution, 2Park Street, London, W.1. 1) BS 2782, “Methods of testing plastics”, Part 1, “Effect of temperature”. 2) BS 410, “Test Sieve”. 3) BS 2782, “Methods of testing plastics”, Part 3, “Mechanical pro
26、perties”. 4) BS 2782, “Methods of testing plastics”, Part 5, “Miscellaneous methods”.BS3241:1960 2 BSI 12-1999 Appendix A Preparation of moulded test sheet The specimens required for certain of the tests set out in the specification shall be cut from sheets0.060 0.002 in (1.52 0.05mm) thick, prepare
27、d by compression moulding. Figure 1 shows a suitable type of mould. The sheets shall not be finished by surface machining,e.g. by sanding or linishing. The material shall be compression moulded at a temperature of not less than180 C. Contact pressure shall be applied for a preheating period of at le
28、ast two minutes. The cooling and full mould pressure of not less than250lb/sq in (17.6kg/cm 2 ) shall then be applied and the pressure maintained until the moulding is sufficiently rigid to be removed without deformation. The sheet shall be free from surface imperfections and voids. Appendix B Metho
29、d of determining impact strength The test shall be carried out by Method306B of BS2782-3 5) , on specimens cut from moulded sheet prepared as inAppendix A. The specimens shall be kept at a temperature of23 2 C for not less than three hours immediately before testing and the test shall be carried out
30、 at23 2 C. The weight increment W lb, shall be ( lb. Appendix C Method of determining tensile strength and elongation at break The test shall be carried out by Method301H of BS2782-3 5) , on specimens cut from moulded sheet prepared as inAppendix A. Alternatively the specimens may be compression mou
31、lded to the appropriate shape under the conditions described inAppendix A. The specimens shall be kept at a temperature of23 2 C for not less than three hours immediately before test and shall be tested at23 2 C. Appendix D Method of determining moisture content A quantity of5to15g of the material s
32、hall be weighed to the nearest 0.001g in clean dry tared flat dish large enough for the granules to form a single layer. The dish and contents shall be heated in an oven at80 2 C for three hours 5minutes. The dish and contents shall be removed from the oven, cooled in a desiccator and then re-weighe
33、d. Calculation. The moisture content of the material shall be calculated from the formula: Appendix E Method of determining colour stability to heat A moulded sheet shall be prepared in accordance withAppendix A. A second sheet shall be similarly prepared except that the moulding shall be made in a
34、press with the platens maintained at225 5 C. After an initial heating period of two minutes under contact pressure, the full moulding pressure of not less than250lb/sq in shall be applied for a further heating period of28minutes. At the end of the heating period the complete mould shall be taken fro
35、m the press and transferred immediately to a second press with cold platens and pressure of not less than250lb/sq in(17.6kg/cm 2 ) applied. The moulding shall be removed when it is cool enough to be extracted without deformation. The two moulded sheets shall be examined visually in daylight and any
36、difference in colour assessed by means of the grey scale specified in BS2662 6) . 5) BS 2782, “Methods of testing plastics”, Part 3, “Mechanical properties”. 6) BS 2662, “Grey scale for assessing change in colour”. Moisture content, per cent loss in weight initial weight of test portion -100 =BS3241
37、:1960 BSI 12-1999 3 Figure 1 MouldBS 3241:1960 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by
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