1、BRITISH STANDARD BS 5350-B5: 1976 Incorporating Amendment No. 1 Methods of test for Adhesives Part B5: Determination of gelation time UDC 665.93:620.1 + 665.93:66.095.26 40BS5350-B5:1976 BSI 11-1999 ISBN 0 580 09103 1 Foreword Gelation time, as defined in clause3, is applicable to solvent-containing
2、 and solventless systems and provides a simple means of assessing the rate of polymerization or the efficiency of curing agents. Certain systems when fully cured may only develop very soft gels which break into lumps upon inversion of the tubes. Similar systems, at an earlier stage of polymerization
3、, will flow evenly and this difference in behaviour may provide an adequate criterion. With hot-melt adhesives, dwell time in the hot application equipment is important. A method for the determination of heat stability of hot-melt adhesives is given in BS5350-H1. A British Standard does not purport
4、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
5、, pages i and ii, page 1 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 Comments 5359 February 1987 Indicated by
6、 a sideline in the marginBS5350-B5:1976 BSI 11-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 References 1 3 Definition 1 4 Method 1: gelation time at 25 C of solvent-containing adhesives 1 5 Method 2: gelation time for solventless adhesives 1 6 Expression of results 1 7 Test report 1i
7、i blankBS5350-B5:1976 BSI 11-1999 1 1 Scope Two methods of test are specified in this Part. Method 1 has an arbitrary endpoint and is suitable for comparative and quality control purposes. Method 2 is suitable for solventless systems and corresponds to BS2782:Method 835C:1980. It can be used for hig
8、h-viscosity materials, which may contain a proportion of solvent. 2 References This Part makes reference to the following standards publications: BS 2782, Methods of testing plastics Method835CDetermination of gelation time of polyester and epoxide resins using a gel timer. BS 5350, Methods of test
9、for adhesives PartH1Determination of heat stability of hot melt adhesives in the application equipment . 3 Definition For the purposes of this Part, the following definition applies. gelation time the time taken for a two (or more) part system to form a gel of reproducible, but arbitrary, consistenc
10、y under standard conditions 4 Method 1: gelation time at 25 C of solvent-containing adhesives 4.1 Principle. The adhesive components are mixed at a specified temperature and maintained, in stoppered glass tubes, at an even temperature. The contents are examined at specified periods for evidence of f
11、low. 4.2 Apparatus 4.2.1 Constant-temperature bath (or oven) capable of being controlled at25 0.2 C. 4.2.2 Glass tubes of approximately150ml capacity and approximately35mm internal diameter, each fitted with an airtight stopper. 4.2.3 Timing device, accurate to1min or less. 4.3 Procedure. Bring the
12、individual components to a temperature of25 1 C and then mix in the proportions and manner described by the manufacturer. The proportions shall be accurate to within2.5% of those specified by the manufacturer. Unless the manufacturers instruction require otherwise, complete the addition and intermix
13、ing of the components in not less than60s and start the timing device as soon as the addition of the final component is completed. Place approximately75ml of the mixed adhesive into each of several of the glass tubes, fit the stoppers and place the tubes vertically in the water bath or oven(4.2.1),
14、controlled at25 0.2 C. Shield the tubes and contents from direct sunlight and leave them undisturbed for a suitable period until tested. NOTEThe preferred periods (in hours) are 2, 8, 24, 36, 48, 72 and 96, but other periods may be selected if necessary so that the final inspection occurs shortly af
15、ter the critical gel formation. If the gel time is required to be less than or more than a specified period, only one tube need be prepared and tested; the method then becomes a pass-or-fail test. At the conclusion of each selected period, invert one tube for30s and examine the contents visually for
16、 signs of flow. Note the time and discard the tube. The gelation time is taken as the time when the contents have ceased to flow. 5 Method 2: gelation time for solventless adhesives Use the method for determining the gelation time of epoxide resins in BS2782:Method 835C:1980. 6 Expression of results
17、 Express the results of the test in hours and minutes as appropriate. 7 Test report The test report shall state the following: a) a designation of the adhesive, giving all information required for complete identification of the sample: b) the mixing proportions of the ingredients; c) the time interv
18、al between mixing and testing; d) the presence or absence of flow after the selected test periods. e) the gelation time of the material; f) the reference to this Part, i.e. BS5350-B5, method1 or method2.BS 5350-B5: 1976 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is t
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