BS 2782-3 Method 360C-1991 Methods of testing plastics - Mechanical properties - Determination of tear resistance of plastics film and sheeting by the initiation method《塑料试验方法 第3部分.pdf

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1、BRITISH STANDARD BS2782-3: Method360C: 1991 Methods of testing Plastics Part3: Mechanical properties Method360C: Determination of tear resistance of plastics film and sheeting by the initiation method IMPORTANT NOTE. Before reading this method it is essential to read BS2782-0, Introduction, issued s

2、eparately.BS2782-3:Method360C:1991 This British Standard, having been prepared under the directionof the Plastics and Rubber Standards Policy Committee, was published underthe authority oftheStandards Board and comes into effect on 29 November1991 BSI11-1999 The following BSI references relate to th

3、e work on this standard: Committee referencePRM/21 Draft for comment91/39409DC ISBN 0 580 20146 5 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics and Rubber Standards Policy Committee (PRM/-) to Technical CommitteePRM/21, upon w

4、hich the following bodies were represented: British Plastics Federation British Steel Industry British Telecommunications plc British Textile Confederation Department of the Environment (Building Research Establishment) Department of Trade and Industry (National Physical Laboratory) EEA (the Associa

5、tion of Electronics, Telecommunications and Business Equipment Industries) Electrical and Electronic Insulation Association (BEAMA Ltd.) Electrical Installation Equipment Manufacturers Association (BEAMA Ltd.) GAMBICA (BEAMA Ltd.) Ministry of Defence PIRA Packaging and Industrial Films Association P

6、lastic Industrial Containers Association Plastics and Rubber Institute RAPRA Technology Ltd. Yarsley Technical Centre Ltd. The following body was also represented in the drafting of the standard, through subcommittees and panels: Malaysian Rubber Producers Research Association Amendments issued sinc

7、e publication Amd. No. Date CommentsBS2782-3:Method360C:1991 BSI 11-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Apparatus 1 4 Test pieces 1 5 Conditioning 2 6 Procedure 2 7 Calculation 2 8 Test report 2 Figure 1 Dimensions of test piece 1 Publ

8、ication(s) referred to Inside back coverBS2782-3:Method360C:1991 ii BSI 11-1999 Foreword This method has been prepared under the direction of the Plastics and Rubber Standards Policy Committee. The method is one of three for the determination of tear strength of sheet as follows: Method360A Elmendor

9、f method (Identical to ISO6383-2:1983) Method360B Trouser tear method (Identical to ISO6383-1:1983) Method360C Initiation method WARNING NOTE. This British Standard method does not necessarily detail all the precautions necessary to meet the requirements of the Health and Safety at Worketc.Act1974.

10、Attention should be paid to any appropriate safety precautions and the method should be operated only by trained personnel. 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

11、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, pagesi andii, pages1and2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amen

12、dments incorporated. This will be indicated in the amendment table on the inside front cover.BS2782-3:Method360C:1991 BSI 11-1999 1 1 Scope This Part of BS2782 describes a method for the determination of the tear resistance of flexible unsupported plastics film and sheeting. The method is suitable f

13、or flexible film and sheeting up to approximately2.5mm in thickness. NOTE 1Before reading this method it is essential to read BS2782-0, issued separately. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Principle Tension is applied to the ends

14、 of a test specimen so shaped that it tears across its width, by the extension of a right-angled discontinuity in one of its long edges to the opposite edge. The tear strength is recorded as the maximum recorded tension in newtons divided by the thickness of the test piece in millimetres. NOTEThe ma

15、ximum force is not usually proportional to thickness so test results from sheets of different thickness are not directly comparable. 3 Apparatus 3.1 Tensile testing machine, complying with BS5214-1 and calibrated to grade B of BS5214-1, fitted with continuous autographic recording of the force appli

16、ed to the test piece and capable of a rate of grip separation of250 25mm/min. NOTEAttention is drawn to the note on force measuring and recording systems in Appendix A of BS2782:Methods320A to320F:1976. 3.2 Test piece grip, of a type that maintains or increases grip pressure as the force applied to

17、the test piece increases, enabling test pieces to be held in such a manner that, as far as possible, slip relative to the grips is prevented. 3.3 Knife-edged punch, producing samples of the dimensions shown in Figure 1 (preferred); or Template and scalpel; or Very sharp knife. 3.4 Thickness measurem

18、ent gauge, accurate either to1m or to1% of the thickness to be measured, whichever is the greater. The gauge shall exert a pressure of20 3kPa through its foot. 4 Test pieces Cut two groups of five test pieces conforming with the dimensions shown in Figure 1 with their major axes respectively paralle

19、l and perpendicular to the length direction of the material. Space the five test pieces across the width of the material. Cut the test pieces either: a) (preferably) with the knife-edged punch(3.3) using a single stroke of a press; or b) with a template and a scalpel, sharp knife or razor blade wher

20、e this is known not to influence the results. NOTEThe reproducibility of this method is critically dependent upon the accuracy and sharpness of the right angle in the side of the test piece. Ensure that the two sides of the angle meet at a true90 . Regularly inspect the cutting edge of the punch and

21、 correct any development of a radius at the right angle by re-sharpening the tool. Figure 1 Dimensions of test pieceBS2782-3:Method360C:1991 2 BSI 11-1999 5 Conditioning Condition the test pieces in accordance with procedure A of BS2782-0:1982 unless the material is known not to be sensitive to humi

22、dity, in which case procedure B shall be used. Report the procedure used. Test the samples under the same conditions. 6 Procedure Determine the thickness of each test piece, in accordance with BS2782:Method630A or BS2782:Method631A. Clamp the ends of the test piece symmetrically in the grips of the

23、testing machine such that the initial length between the grips is65 5mm, then separate the grips at250 25mm/min and record the maximum force registered. Repeat the procedure for two more test pieces cut from the same sample. 7 Calculation Calculate the tear strength (S i ) of the test piece as the m

24、aximum force in newtons registered during the determination, divided by the thickness of the test piece in millimetres. Report the arithmetic mean of the five results as the tear initiation of the strength of the sample, S i(inkN/m). 8 Test report The test report shall include the following particul

25、ars. a) A complete identification of the material tested, including type, source, manufacturers code numbers, form, principal dimensions, previous history, etc. b) A reference to this British Standard method, i.e.BS2782:Method360C. c) The conditioning and test atmosphere used. d) The procedure used

26、for thickness determination. e) The tear strength of the sample. f) The individual test results.BS2782-3:Method360C:1991 BSI 11-1999 Publication(s) referred to BS2782, Methods of testing plastics. BS2782-0, Introduction. BS2782:Methods320A to320F, Tensile strength, elongation and elastic modulus. BS

27、2782:Method630A, Determination of thickness by mechanical scanning of flexible sheet. BS2782:Method631A, Determination of gravimetric thickness and yield of flexible sheet. BS5214, Specification for testing machines for rubbers and plastics. BS5214-1, Constant rate of traverse machines. BS2782-3: Me

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