1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 1238:2011Adhesives Determinationof the softening point ofthermoplastic adhesives (ringand ball)BS EN 1238:2011 BRITISH STANDARDNational forewordThis British Standard is the
2、 UK implementation of EN 1238:2011. Itsupersedes BS EN 1238:1999 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/52, Adhesives.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not
3、 purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 72242 4ICS 83.180Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStand
4、ards Policy and Strategy Committee on 31 May 2011.Amendments issued since publicationDate Text affectedBS EN 1238:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1238 April 2011 ICS 83.180 Supersedes EN 1238:1999English Version Adhesives - Determination of the softening point of thermoplast
5、ic adhesives (ring and ball) Adhsifs - Dtermination du point de ramollissement des adhsifs thermoplastiques (mthode bille et anneau) Klebstoffe - Bestimmung des Erweichungspunktes von thermoplastischen Klebstoffen (Ring und Kugel) This European Standard was approved by CEN on 10 March 2011. CEN memb
6、ers are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on applicati
7、on to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Managem
8、ent Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlan
9、ds, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in a
10、ny form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1238:2011: EBS EN 1238:2011EN 1238:2011 (E) 2 Contents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Terms and definitions .54 Principle 55 Apparatus .56 Sampling .87 Preparation of sample .88 Proced
11、ure .99 Expression of results . 1010 Test report . 10Annex A (normative) Thermometer specification . 11BS EN 1238:2011EN 1238:2011 (E) 3 Foreword This document (EN 1238:2011) has been prepared by Technical Committee CEN/TC 193 “Adhesives”, the secretariat of which is held by AENOR. This European Sta
12、ndard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2011, and conflicting national standards shall be withdrawn at the latest by October 2011. Attention is drawn to the possibility that some of the elements of
13、 this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 1238:1999. The main modifications regarding the previous version are in the Foreword, Normative References and Note in 5.8.
14、This European Standard includes Annex A (normative) “Thermometer specification“. SAFETY STATEMENT Persons using this document should be familiar with the normal laboratory practice, if applicable. This document does not purport to address all of the safety problems, if any, associated with its use.
15、It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory conditions. ENVIRONMENTAL STATEMENT It is understood that some of the material permitted in this standard may have negative environmental impact. As technological ad
16、vantages lead to acceptable alternatives for these materials, they will be eliminated from this standard to the extent possible. At the end of the test, the user of the standard should take care to carry out an appropriate disposal of the wastes, according to local regulation. According to the CEN/C
17、ENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithu
18、ania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 1238:2011EN 1238:2011 (E) 4 Introduction Thermoplastic adhesives do not change from the solid to the liquid state at a fixed temperature, but their vi
19、scosity decreases progressively as the temperature rises. For this reason, the determination of the softening point shall be carried out by defined methods to obtain comparable results. BS EN 1238:2011EN 1238:2011 (E) 5 1 Scope This European Standard specifies a method for the determination of the s
20、oftening point of hot-melt adhesives. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendment
21、s) applies. EN 923:2005+A1:2008, Adhesives Terms and definitions EN 1067, Adhesives Examination and preparation of samples for testing EN ISO 15605, Adhesives Sampling (ISO 15605:2000) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 923:2005+A1:2008 a
22、nd the following apply. 3.1 softening point temperature at which the adhesive under test attains a degree of softness under the specified conditions 4 Principle A steel ball of a specified mass is placed on a sample of adhesive contained on a metal ring of specified dimensions. The apparatus is heat
23、ed at a constant defined rate. The temperature at which the sample is sufficiently soft to allow the ball to pass through the ring by a fixed distance is taken as the “softening point“. 5 Apparatus 5.1 Ball, two steel balls, (9,53 0,02) mm in diameter, each having a mass of (3,50 0,05) g. 5.2 Ring,
24、tapered brass ring to the dimensions of Figure 1. NOTE As alternative the following can be used: a) shouldered brass ring to the dimensions of Figure 2; b) a straight-sided cylindrical ring with the following: 1) interior diameter (15,9 0,1) mm; 2) depth (6,4 0,1) mm. BS EN 1238:2011EN 1238:2011 (E)
25、 6 Dimensions in millimetres Figure 1 Tapered brass ring Dimensions in millimetres Figure 2 Shouldered brass ring To ensure the correct positions of the ring in its support, the exterior diameter shall be reduced at the lower part to (19,0 0,1) mm for a depth of 2 mm. If a shouldered or straight-sid
26、ed ring is used, this shall be noted in the test report. 5.3 Guide, to center the ball, the arrangement in Figure 3 is recommended to be used. BS EN 1238:2011EN 1238:2011 (E) 7 Dimensions in millimetres Figure 3 Ball centering guide 5.4 Ring supports The support described in Figure 4 shall be used.
27、The distance between the two supports plates is (25 1) mm. The same distance separates the ring holder from the bottom plate. Dimensions in millimetres Key 1 Ring holder 2 Base Figure 4 Ring holder and base BS EN 1238:2011EN 1238:2011 (E) 8 5.5 Thermometer, conforming to the specification of Annex A
28、. 5.6 Bath, of heat resistant glass, to the dimensions of Figure 5, with the rings supported horizontally as shown. The bottom of the bulb of the thermometer shall be level with the bottom of the rings and within 10 mm of them, but not touching them. 5.7 Stirrer, to ensure uniform heat distribution
29、throughout the bath a mechanical stirrer which operates smoothly shall be used. It shall be so placed that the samples are not disturbed when it is in operation. 5.8 Bath liquid Water may be used to 80 C. Glycerol may be used up to 200 C. Above 200 C a liquid heat-transfer medium shall be chosen whi
30、ch is stable at the temperatures likely to be used; mineral or silicone oils are suitable. The liquid used shall not affect the specimen at the test temperature. NOTE Automatic apparatus for measuring the softening point of thermoplastics adhesives is commercially available. Differences in the softe
31、ning point of some hot melt adhesives (e.g. poly(ethylene-vinylacetate) based adhesives) measured by automatic or manual equipment can occur. In such case comparative tests should be carried out to determine whether it is necessary to apply a correction factor. 6 Sampling A significant sample of the
32、 adhesive shall be taken in accordance with EN ISO 15605 and prepared for testing as described in EN 1067. 7 Preparation of sample 7.1 Preparation of test specimens in duplicate Heat a portion of the sample in air or a liquid bath, to obtain an approximate value of the softening point. When this is
33、noted continue until the temperature of the sample is between 25 C and 50 C above the softening point noted. Stir the sample during heating until it is completely fluid, homogeneous, and free from air bubbles. If necessary, pour the fluid sample through a 315 m sieve, to remove solid impurities. Hea
34、t the ring to the same temperature as the sample under test on a metal, porcelain or heat resistant glass plate, coating lightly with oil or silicone grease to prevent adhesive sticking. Fill the ring with an adequate amount of fluid adhesive, so that a slight excess remains after cooling. Cool in a
35、ir for 30 min removing excess adhesive with a heated knife. 7.2 For heat sensitive adhesives Carry out the above method in an inert atmosphere, or by another method agreed by the parties concerned. NOTE If guides (see Figure 3) are not being used, a mark for the balls should be made in the middle of
36、 the prepared specimens, just deep enough to ensure that they cannot move and are centred in the rings. BS EN 1238:2011EN 1238:2011 (E) 9 8 Procedure 8.1 Prepare the apparatus as indicated in Figure 5, ensuring the rings are horizontal. Dimensions in millimetres Key 1 Liquid level 4 Shouldering ring
37、, see Figure 2 2 Thermometer 5 Ring holder, see Figure 4 3 Steel ball 6 Base, see Figure 4 Figure 5 Complete test assembly 8.2 Sample softening points expected to be below 80 C. a) Start from a temperature at least 10 C below the expected softening point, using the liquid maintained at that temperat
38、ure in a thermostat bath for at least 15 min. Using forceps, place the balls, previously kept at the same temperature in the same thermostat, into the guides. b) Heat the apparatus and stir the liquid so that the temperature rises at a uniform rate of (5 1) C/min until the balls fall through the rin
39、gs. Do not average the rate of temperature rise over the test period. Reject any determination in which the rate of temperature rise does not fall within the specified limits after the first 3 min. Record for each ring and ball the temperature shown by the thermometer at the instant the sample surro
40、unding the ball touches the bottom plate. BS EN 1238:2011EN 1238:2011 (E) 10 8.3 Sample softening points to be above 80 C. Fill the bath with glycerol or oil as indicated in 5.8. Maintain the bath at 35 C for 15 min and using forceps, place the balls, previously brought to 35 C, in each ball guide.
41、Follow the procedure of 8.2, b). 9 Expression of results As softening point report the mean of the temperatures recorded in duplicate determinations, without correction of the emergent stem of the thermometer, rounded to the nearest 0,5 C if the recorded temperature is 100 C or below; 1 C if the rec
42、orded temperature is between 100 C and 260 C, and 2 C if the recorded temperature is above 260 C. 10 Test report The test report shall include: a) reference to this European Standard, i.e EN 1238; b) type and designation of the adhesive tested; c) type of ring used, if the tapered one (see Figure 1)
43、 is not used; d) type of ring heating fluid used; e) use or not of inert atmosphere; f) test temperature; g) result of the test expressed in accordance with Clause 9; h) any circumstances which may have affected the result; i) date of the test. BS EN 1238:2011EN 1238:2011 (E) 11 Annex A (normative)
44、Thermometer specification Table A.1 Thermometer specification Characteristics Low range Medium range High range Immersion Partial Partial Partial Temperature scale - 1 C to 101 C - 10 C to 260 C - 10 C to 400 C Subdivisions 0,1 C 1 C 2 C Max. error (at all points of the scale) 1 C 1 C to 100 C 1,5 C
45、 above 100 C 2,5 C to 300 C 5 C above 300 C Min. scale (mm length) 500 250 250 Diameter (mm) 5,5 to 8 5,5 to 8 5,5 to 8 This page deliberately left blankThis page deliberately left blankBSI is the independent national body responsible for preparing British Standardsand other standards-related public
46、ations, information and services. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter.British Standards Institution (BSI)raising standards worldwideBSI Group Headquarters389 Chiswick High Road London W4 4AL UKTel +44 (0)20 8996 9001Fax +
47、44 (0)20 8996 Standards are updated by amendment or revision. Users of British Stan-dards should make sure that they possess the latest amendments or editions.It is the constant aim of BSI to improve the quality of our products and serv-ices. We would be grateful if anyone finding an inaccuracy or
48、ambiguity whileusing this British Standard would inform the Secretary of the technical com-mittee responsible, the identity of which can be found on the inside frontcover.Tel: +44 (0)20 8996 9001 Fax: +44 (0)20 8996 7001BSI offers Members an individual updating service called PLUS which ensuresthat
49、subscribers automatically receive the latest editions of standards.Tel: +44 (0)20 8996 7669 Fax: +44 (0)20 8996 7001Email: Buying standardsYou may buy PDF and hard copy versions of standards directly using acredit card from the BSI Shop on the website addition all orders for BSI, international and foreign standards publicationscan be addressed to BSI Customer Services.
