1、BRITISH STANDARD BS 2782-8: Method 835A: 1980 Methods of testing Plastics Part 8: Other properties Method 835A: Determination of gelation time of phenolic resins IMPORTANT NOTE. Before reading this method it is essential to read the foreword, general introduction and instructions to BS 2782, issued
2、separately. UDC 678.5/.8:678.01:536.421.4:678.632BS2782-8:Method 835A:1980 This British Standard, havingbeen prepared under thedirection of the Plastics Standards Committee, was published under the authority ofthe Executive Board and comesinto effect on 30 May 1980 BSI 08-1999 The following BSI refe
3、rences relate to the work on this standard: Committee reference PLC/17 Draft for approval 79/51003 DC ISBN 0 580 11311 6 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 wit
4、h 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, pages1 and 2 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated.
5、This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS2782-8:Method 835A:1980 BSI 08-1999 i Contents Page 0 Introduction 1 1 Scope 1 2 References 1 3 Principle 1 4 Apparatus 1 5 Test temperature 1 6 Procedure 2 7
6、 Expression of results 2 8 Test report 2ii blankBS2782-8:Method 835A:1980 BSI 08-1999 1 0 Introduction This method has been prepared under the direction of the Plastics Standards Committee. It is one of a series of methods for determination of gelation time of resins, the other methods being as foll
7、ows. It should be noted that BS 4584 “Metal-clad base materials for printed circuits” Part 11 “Bonding sheet material for use in the fabrication of multilayer printed boards: EP-GC-11” also includes a method for testing resins used for laminates, etc. This method describes a procedure for determinin
8、g the time for a liquid phenolic resin or a solution of a phenolic resin to set to a rubbery state when maintained at an elevated temperature. The method is technically equivalent to methods111A and 111B of BS 2782:1970 which are therefore being withdrawn. It is suitable for testing phenolic resins
9、used for the manufacture of fibre reinforced plastics by laminating or moulding processes. 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 preca
10、utions, and the method should be operated only by trained personnel. 1 Scope This method describes a procedure for determining the time for a liquid phenolic resin or a solution of phenolic resin to set to a rubbery state when maintained at a specified elevated temperature. 2 References The followin
11、g standards publications are referred to in this method. BS 593, Laboratory thermometers. BS 700, Specification for graduated pipettes (including blowout pipettes). BS 3218, Test tubes and boiling tubes. 3 Principle A small volume of the material is heated in a bath and tested at intervals to determ
12、ine when it reaches a rubbery state. 4 Apparatus The following apparatus is required. 4.1 Heating bath, consisting of a 2 litre heat resistant glass beaker filled to within 25 mm of the top with a suitable liquid such as a silicone oil, provided with a mechanical stirrer and capable of being maintai
13、ned at the required temperature within 0.5 C. The liquid in the bath shall be such that the test sample can be clearly seen during the test. 4.2 Thermometers, of suitable range as required, complying with the requirements of BS593. 4.3 Test tubes (two), of soda glass 0.5 0.1 mm thick,9.5 0.5 mm diam
14、eter and 49 mm to 78 mm in length. NOTELight wall soda glass tubes of nominal sizes50mm 10mm or 70 mm 10 mm complying with the requirements of BS 3218 are suitable. 4.4 Graduated pipette, capacity 1 ml, complying with the requirements of BS 700. 4.5 Heat resistant glass rods (two), 115 mm to140mm in
15、 length and 3 mm to 4 mm in diameter, with one end of the rod drawn to a point and a small bead of glass 1.5 mm to 2 mm in diameter formed at the end. 4.6 Timing device, accurate to 1 s or less. 5 Test temperature The test temperature shall be as specified in the relevant product specification. Wher
16、e there is no product specification other test temperatures may be used depending on the choice of a suitable liquid for the heating bath. NOTEThe temperatures used in methods 111A and 111B of BS2782:1970 were 130 C and 150 C respectively. Method 835B Determination of gelation time of polyester resi
17、ns (manual method) Method 835C Determination of gelation time of polyester and epoxide resins using a gel timer Method 835D Determination of gelation time of thermosetting resins using a hot plate Method 835E Determination of gelation time of resin in impregnated materials used for laminatesBS2782-8
18、:Method 835A:1980 2 BSI 08-1999 6 Procedure Heat the bath to the specified temperature with a tolerance of 0.5 C and maintain it at this temperature. Immerse one of the test tubes containing one of the glass rods in the bath to a depth of 27 2 mm and clamp it in this position, insulating the test tu
19、be from the clamp. After not less than 5 min, add as nearly as possible into the bottom of the test tube by means of the pipette, a volume of the test sample corresponding to0.2 0.01 g of resin. Complete the addition of the test portion to the test tube in not more than 30 s and as soon as completed
20、, start the timing device. With a steady circular motion, carefully stir the test sample with the beaded end of the glass rod throughout the last 10 s of each minute after starting the timing device and then raise the rod so that the bead is about 10 mm above the bottom of the test tube. 2 min befor
21、e the expected gelation time carry out the 10 s stirring and lifting operations at intervals of 30 s. Stop the timing device when the test portion becomes sufficently rubbery for the string of resin, raised when the rod is lifted from the bottom of the test tube, to break when the top of the rod rea
22、ches10 mm above the bottom of the test tube. Make a second determination using a fresh test portion of the material. NOTEIf necessary, the tip of the pipette may be removed to facilitate filling with, and discharge of, viscous liquids. Very viscous materials may be introduced with care from a coatin
23、g on the outside of the end of the pipette or an alternative rod. 7 Expression of results Calculate the mean of the two results and report this mean as the gelation time expressed in minutes. 8 Test report The test report shall include the following particulars. a) A complete identification of the m
24、aterial tested, including type, source, manufacturers code number and previous history. b) A reference to this British Standard method, i.e. BS 2782:Method835A:1980. c) The test temperature. d) The result of the test and, if required, the individual results.blankBS 2782-8: Method 835A: 1980 BSI 389
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