BS-2782-6-METHOD-641A-1983.pdf

BRITISH STANDARD CONFIRMED FEBRUARY 1991 BS 2782-6: Method 641A: 1983 Incorporating Amendment No. 1 Methods of testing Plastics Part 6: Dimensional properties Method 641A: Determination of dimensional stability at 100 °C of flexible polyvinyl chloride sheet IMPORTANT NOTE. Before reading this method it is essential to read BS 2782-0, issued separately. UDC 678.5/.8:678.01:620.179.7 97C100:678.743.22 41 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 08:42:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2782-6:Method 641A:1983 This British Standard, having been prepared under the direction of the Plastics Standards Policy Committee, was published under the authority of the Board of BSI and comes into effect on 28 February 1983 © BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PLC/40 Draft (reference 82/52804) announced in BSI News September 1980 ISBN 0 580 13177 7 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 document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover 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. Amendments issued since publication Amd. No.Date of issueComments 6282February 1991Indicated by a sideline in the margin Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 08:42:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2782-6:Method 641A:1983 © BSI 12-1999i Contents Page 0Introduction1 1Scope1 2Principle1 3Form of test specimen1 4Number of test specimens1 5Procedure1 6Expression of results1 7Report1 Publication referred toInside back cover Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 08:42:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 08:42:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2782-6:Method 641A:1983 © BSI 12-19991 0 Introduction This method has been prepared under the direction of the Plastics Standards Policy Committee. Method 641A is an editorial revision of method 106F of BS 2782:1970, which is being withdrawn. WARNING NOTE. This method does not necessarily detail all precautions necessary to meet the requirements of the Health and Safety at Work etc. Act 1974. Attention should be paid to any appropriate safety precautions, and the method should be operated only by trained personnel. 1 Scope This method describes a procedure for assessing the relative amount of moulded-in strain in flexible PVC sheet, a factor affecting the dimensional stability of the material at room temperature. NOTEThe title of the publication referred to in this standard is given on the inside back cover. 2 Principle Method 641A determines the reduction in length of a rectangular piece of flexible polyvinyl chloride sheet when it is heated at 100 °C for 15 min. 3 Form of test specimen The test specimen shall be a piece 250 mm long and 6 mm to 7 mm wide cut from a sample taken from a roll or a sheet. Immediately after the sample has been taken it shall be kept at a temperature not exceeding 30 °C and then kept at 23 ± 2 °C for not less than 2 h immediately before the test specimen is cut and measured. 4 Number of test specimens The number of test specimens and the positions within the sheet or roll of sheet under test from which they shall be cut shall be as specified in the relevant British Standard for the material. 5 Procedure Measure the length (L1) of the test specimen to the nearest 0.5 mm. Take care that the test specimen remains flat and straight when its length is measured. NOTEA convenient method of ensuring that it does, is to place the test specimen in a rectangular groove approximately 300 mm long, 7 mm wide and 1.5 mm deep in a block of wood or other suitable material with a flat upper surface. Measurements of length may be made with a transparent rule suitably graduated and fitting into the groove. When the test specimen has been measured, immerse it for a period of 15 ± 1 min in a water bath at a temperature of 100 ± 1 °C. Ensure that the test specimen does not touch the sides or bottom of the water bath. NOTEA cage of metal gauze with feet is a suitable means of achieving this. On removal from the water, allow the test specimen to cool in air at 23 ± 2 °C for at least 15 min. Take care to avoid stretching the test specimen in handling it. Then measure the length (L2) of the test specimen to the nearest 0.5 mm. Calculate the change in length of the test specimen as follows: percentage change = where Repeat the above procedure for remaining test specimens. 6 Expression of results Express the dimensional stability at 100 °C of the material under test as the percentage change in length of the test specimen that shows the greatest change. 7 Report The report shall state: a) a complete identification of the material tested including type, source, manufacturers code number etc.; b) a reference to this British Standard method, i.e. BS 2782:Method 641A:1983; c) the dimensional stability at 100 °C of the material; d) the individual test results and the positions of the test specimens relative to the roll or sheet under test; e) the conditioning, if any, of the test specimens. L1is the initial length of the test specimen, and L2is the length of the test specimen after heating and cooling in air. L1L2 L1 - -100× Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 08:42:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 blank Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 08:42:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2782-6:Method 641A:1983 © BSI 12-1999 Publication referred to BS 2782, Methods of testing plastics. BS 2782-0, Introduction. Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 08:42:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2782-6: Method 641A: 1983 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 Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. 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