1、BRITISH STANDARD BS 5350-H1: 1981 Methods of test for Adhesives Part H1: Determination of heat stability of hot melt adhesives in the application equipment UDC 665.93:620.192.424BS5350-H1:1981 This British Standard, having been prepared under the directionof the Adhesives Standards Committee, was pu
2、blished under the authority ofthe Executive Board and comesinto effect on 31 July 1981 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference ADC/9 Draft for comment 80/50978 DC ISBN 0 580 12180 1 Foreword A hot melt adhesive may undergo irreversible change
3、s during processing in the application equipment. The rate of change increases with temperature and the degree of change increases with time. Deterioration in performance is indicated by one or more of the following changes: a) liquid phase separation; b) change in viscosity; c) skin formation and/o
4、r gel formation; d) sedimentation; e) discoloration. WARNING NOTE. This British Standard method does not necessarily detail all precautions necessary to meet the requirements of the Health and Safety at Work etc. Act1974. Attention should be paid to any appropriate safety precautions and the method
5、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 with a British Standard does not of itself confer immunity from legal obligati
6、ons. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2 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. A
7、mendments issued since publication Amd. No. Date of issue CommentsBS5350-H1:1981 BSI 10-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 Principle 1 3 Supplementary information 1 4 Apparatus 1 5 Procedure 1 6 Test report 2ii blankBS5350-H1:1981 BSI 10-1999 1 1 Scope This Part describes a
8、 method for determining the stability of a hot melt adhesive during processing at elevated temperatures. The method does not apply to adhesives in the final bonded state. It is particularly applicable to hot melt adhesives used in processes or equipment where a reservoir of adhesive is kept molten a
9、t or near the application temperature. The test can be used in two ways: a) to examine test portions at intervals to determine the trend in the properties under investigation; b) to establish whether or not the adhesive meets the specified or agreed requirements, for example that its viscosity stays
10、 below a given value when the adhesive is held for a given period at a given temperature. The method of test is suitable for temperatures up to300 C and a maximum ageing period of three days. 2 Principle Test portions of the adhesive, each of a similar surface area to volume ratio, are aged in air a
11、t an elevated temperature. At appropriate intervals a test portion is inspected for skin formation, signs of gelation and liquid phase separation, and has its colour measured or compared and its viscosity measured. 3 Supplementary information The following data shall be established before the test i
12、s carried out (see also clause 6): a) the size and material of the containers to be used to hold the samples for ageing in the oven (see 4.2); b) the quantity of adhesive to be placed in each container, if other than specified in5.1; c) the ageing temperature; NOTEThe ageing temperature may or may n
13、ot be the temperature recommended for the use of the adhesive but it is normally not more than 20 C above the maximum temperature of use. d) whether the containers are to be closed or left open and if closed the nature of the closure; e) the temperature at which the viscosity is to be determined; f)
14、 the method by which colour is to be determined. If this is a visual assessment method then the size of the test portion and the type of observation shall be established. This information shall be derived from the national standard or other document for the product under test or, where appropriate,
15、shall be the subject of agreement between the interested parties. 4 Apparatus 4.1 Glass or metal containers, volume approximately 125ml, height approximately 60mm and diameter approximately 60mm, with loose fitting covers (see note in 5.1). 4.2 Oven, with fan, capable of being controlled to 2 C. 4.3
16、 Colour comparator with suitable glass colour standards (if needed). 5 Procedure 5.1 Preparation of test portions. Take a number of the containers equal to the number of test periods appropriate to the stability of the adhesive plus an extra container. Weigh into each 100g of the test sample (see no
17、te) at laboratory temperature and cover the containers. NOTEAdhesives based on ethylene vinyl acetate (EVA) polymers are more stable than adhesives based on other polymers. The maximum testing period may extend to three days for the former, but is usually less than 24h for the latter. The 100g test
18、portion is typical of tests carried out on adhesives based on EVA polymers. For other types of adhesive where the testing times are shorter it may be necessary to use a smaller test portion and a correspondingly smaller container. 5.2 Test procedure. Adjust the temperature of the test portion in one
19、 of the containers to the specified or agreed test temperature. Remove a small amount and either retain it for visual comparison of colour or allow it to cool and measure the colour using the colour comparator. Determine the viscosity of the remaining adhesive in the container using an appropriate m
20、ethod described in PartB8“Determination of viscosity”. Place the remaining containers and contents in the oven controlled at the specified temperature. Note this time as the commencement of the test. After completion of each test period, remove one of the containers from the oven and examine the adh
21、esive for skin formation, signs of gelation, liquid phase separation and sedimentation. If skin is present carefully remove it and mix the adhesive. Remove a small amount and either compare the colour visually with the retained sample or allow it to cool and measure the colour with the comparator. D
22、etermine the viscosity by the same method as used for the initial test. If the adhesive shows signs of serious deterioration, such as liquid phase separation, terminate the test. NOTEIf necessary, this procedure may be repeated using a series of ageing temperatures.BS5350-H1:1981 2 BSI 10-1999 6 Tes
23、t report The report shall state the following: a) a designation of the adhesive, giving all information required for complete identification of the sample; b) the items of supplementary information given in clause3; c) the results of the test: 1) whether liquid phase separation occured and the test
24、periods between which it occured; 2) the initial viscosity (in Pa s), the viscosity after each test period and the temperature of the determination; 3) the degree of skinning after each test period,i.e. no skinning, incomplete skinning of the surface, complete skinning covering the surface, or heavy
25、 skinning; 4) the test periods between which particles of gel formed; 5) whether sedimentation occurred and the time at which it occurred; 6) the initial colour and the colour after each test period; d) that the method of test complied with the requirements of this standard,i.e. BS5350-H1, or if it
26、did not the respects in which it did not, together with full details of the particular apparatus used.3 blankBS 5350-H1: 1981 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK vi
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