1、BSI Standards PublicationBS EN 16556:2014Determination of the maximumopen time for thermoplasticwood adhesives for non-structural applicationsBS EN 16556:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 16556:2014.The UK participation in its preparation was
2、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 purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Sta
3、ndards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 78070 7ICS 83.180Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 November 2014.Ame
4、ndments issued since publicationDate Text affectedBS EN 16556:2014EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16556 November 2014 ICS 83.180 English Version Determination of the maximum open time for thermoplastic wood adhesives for non-structural applications Dtermination du temps ouvert m
5、aximal des adhsifs thermoplastiques pour bois pour applications non structurales Bestimmung der maximalen offenen Wartezeit bei thermoplastischen Holzklebstoffen fr nicht tragende Anwendungen This European Standard was approved by CEN on 20 September 2014. CEN members are bound to comply with the CE
6、N/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 application to the CEN-CENELEC Management Ce
7、ntre 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 Management Centre has the same status as t
8、he official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Nethe
9、rlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rig
10、hts of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16556:2014 EBS EN 16556:2014EN 16556:2014 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Symbols and abbreviations 4 5 Sampling .4 6 Principle 5 7
11、 Apparatus .5 8 Procedure .5 8.1 General 5 8.2 Preparation of test pieces .5 8.3 Number of test pieces .6 8.4 Tensile shear test.6 9 Expression of results 8 10 Test report 9 Bibliography . 10 BS EN 16556:2014EN 16556:2014 (E) 3 Foreword This document (EN 16556:2014) has been prepared by Technical Co
12、mmittee CEN/TC 193 “Adhesives”, the secretariat of which is held by AENOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2015 and conflicting national standards shall be withdrawn at the lat
13、est by May 2015. Attention is drawn to the possibility that some of the elements of 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. Safety statement Persons using this document should be familiar with
14、the normal laboratory practice, if applicable. This document cannot address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory conditions. Environmental st
15、atement It is understood that some of the material permitted in this standard can have negative environmental impact. As technological advantages lead to better alternatives for these materials, they will be eliminated from this standard to the extent possible. At the end of the test, it is recommen
16、ded that the user of the standard take care to carry out an appropriate disposal of the wastes, according to local regulation. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Be
17、lgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Swit
18、zerland, Turkey and the United Kingdom. BS EN 16556:2014EN 16556:2014 (E) 4 1 Scope This European Standard defines the test method for the determination of the maximum open time for thermoplastic wood adhesives for non-structural applications by tensile shear strength. It is carried out on standardi
19、zed test pieces glued with increasing open times. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest editi
20、on of the referenced document (including any amendments) applies. EN 923, Adhesives - Terms and definitions EN 1067, Adhesives - Examination and preparation of samples for testing EN ISO 15605, Adhesives - Sampling (ISO 15605) ISO 5893, Rubber and plastics test equipment Tensile, flexural and compre
21、ssion types (constant rate of traverse) Specification 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 923 and the following apply. 3.1 maximum open time the longest time within which two wooden adherends, where the adhesive is applied, can remain deco
22、upled ensuring a tensile force value 10 N/mm2and a wood failure 0 % Note 1 to entry: The open time is expressed in minutes (min). 4 Symbols and abbreviations A bonded test surface, in square millimetres (mm); a thickness of bond-line, in millimetres (mm); angle between growth ring and surfaces to be
23、 bonded, in grades ( ); b width of test piece, in millimetres (mm); Fmaxthe applied load at failure, in Newton (N); l1length of test piece, in millimetres (mm); l2length of overlap (length of tested surface), in millimetres (mm); s thickness of the panels, in millimetres (mm); shear strength, in New
24、ton (N). 5 Sampling Samples of the adhesive shall be taken according to EN ISO 15605 and prepared for testing according to EN 1067. BS EN 16556:2014EN 16556:2014 (E) 5 6 Principle A symmetrical bonded single lap joint between two wooden adherends glued with increasing open times, is strained to rupt
25、ure by a tensile force parallel to the grain. 7 Apparatus a) Conditioning room capable of ensuring to the test pieces the temperature at (23 2) C and (50 5) % relative humidity or (20 2) C and (65 5) %. b) Notched trowel suitable to apply on the surface of the boards the required adhesive amount. c)
26、 The testing machine shall be a constant-rate-of-traverse machine as described in ISO 5893. The machine shall be capable to apply a rate of 50 mm/min. The machine shall apply a force of at least 5 kN 2%. d) The jaws shall grip the test pieces with a wedge action and permit self alignment whilst the
27、test pieces are being pulled. e) Apparatus suitable to obtain individual test pieces from the boards coupled as reported in 8.2, for example a circular saw fitted with blade having a thickness of cut of about 2,5 mm. f) Press suitable to glue two boards (8.1) as indicated in 8.2 with the required pr
28、essure. 8 Procedure 8.1 General Cut two panels (see Figure 1) from a thick unsteamed, conditioned, straight-grained board of beech (Fagus sylvatica L.) with a density of (700 50) kg/m3when the moisture content is (12 1) %. Ensure that the angle between the growth rings and the surface to be bonded i
29、s between 30 and 90. Condition the boards for at least 7 days in 7 a) conditions. The adhesive shall be conditioned for at least 24 h. Not more than 24 h before bonding, either lightly plane or lightly sand each surface to be bonded (using an abrasive paper of grain size P100 complying with ISO 6344
30、-2 is recommended). Remove any dust carefully. Do not touch or soil the prepared surfaces. 8.2 Preparation of test pieces All the adhesive application procedures shall be carried out in the standard atmosphere (see 7a). Assembly instructions: The adhesive application shall be on one adherend only. T
31、he adhesive spread shall be (150 10) g/m2. The distribution of the adhesive shall be uniformly done over the whole surface of the board. Immediately after the adhesive application has been completed, the measurement of the open time shall start. The closed assembly time shall be (180 30) s. The pres
32、sing pressure shall be (0,8 0,1) N/mm2. BS EN 16556:2014EN 16556:2014 (E) 6 The pressing time shall be a minimum of 2 h. Assemble the boards at increasing open times (see note) or according to the manufacturers instructions (range of the maximum open time to be tested and the interval). NOTE e.g. 0-
33、3-6-9-12 min. The glued boards shall be conditioned for 7 days in standard atmosphere (see 7a). Cut five strips of width b = (20 0,2) mm from each bonded assembly along the grain, avoiding areas within 7,5 mm of the outside long edges of the panel as shown in Figure 1. Cut these strips into test pie
34、ces of length l1= (150 5) mm as shown in Figure 2. Make flat bottomed cuts of (2,5 0,5) mm wide in the bonded sections across the grain so that an overlap of length l2= (10,0 0,2) mm is defined in the middle section (see Figure 2). The cuts are to separate the wood layers. Take care that the cuts co
35、mpletely cut through the bond line but only penetrate as little as possible into the other part of the joint. For a screening test only (e.g. to determine a rough value of the open time), single lap joint specimens (e.g: see EN 205:2003, Annex A), may be used. 8.3 Number of test pieces Test a suffic
36、ient number of test pieces to provide 10 valid results for each of the open times selected. Results from tests in which failure occurred in the wood (100 % of wood failure) at values 10 N/mm2shall be invalid. 8.4 Tensile shear test Test the test pieces shown in Figure 2 in the tensile testing machin
37、e (see 7 c). Clamp the ends of the test pieces in the jaws of the tensile testing machine up to a length of 40 mm to 50 mm. Ensure that the force is applied centrally and in the plane of the bond. Load the test piece until rupture. Record the applied maximum force Fmaxin Newton (N). BS EN 16556:2014
38、EN 16556:2014 (E) 7 Dimensions in mm Key a = (1,0 0,1) mm thickness of bond-line b = (20,0 0,2) mm width of test piece l1= (150 5) mm length of test piece s = (5,0 0,1) mm thickness of the panels Figure 1 Example of a bonded panel marked for division into individual test pieces using 2,5 mm saw cuts
39、. BS EN 16556:2014EN 16556:2014 (E) 8 Dimensions in mm Key = 30 to 90 (grades) angle between growth ring and surfaces to be bonded b = (20,0 0,2) mm width of test piece (width of tested surface) l1= (150 5) mm total length of test piece l2= (10,0 0,2) mm length of overlap (length of tested surface)
40、s = (5,0 0,1) mm thickness of the panels Figure 2 Lap joint test piece 9 Expression of results For each of the test pieces (see Figure 2) the results shall be expressed as follows: The strength in Newton per square millimetre (N/mm2) shall be calculated using formula: max2Flb =(1) where Fmaxis the a
41、pplied maximum force in Newton (N); l2is the nominal length of the bonded test surface in millimetres (mm); b is the nominal width of the bonded test surface in millimetres (mm); l2x b= 200 mm2. The adhesive strength for each open time value considered shall be assumed to be the arithmetical mean of
42、 the values found on the individual test piece. BS EN 16556:2014EN 16556:2014 (E) 9 10 Test report The test report shall contain the following information: a) a reference to this European Standard; b) the identification elements of the adhesive tested: (e.g. commercial name, etc.); c) the characteri
43、stic data relating to the procedure followed to perform the gluing (see 8.2); d) the open time in minutes; e) any deviation from the standard; f) the date of test; g) the reference to the used conditioning atmosphere. BS EN 16556:2014EN 16556:2014 (E) 10 Bibliography 1 ISO 6344-2, Coated abrasives G
44、rain size analysis Part 2: Determination of grain size distribution of macrogrits P12 to P220 2 EN 205:2003, Adhesives Wood adhesives for non-structural applications Determination of tensile shear strength of lap joints This page deliberately left blankBSI is the national body responsible for prepar
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