1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 1243:2011Adhesives Determinationof free formaldehyde in aminoand amidoformaldehydecondensatesBS EN 1243:2011 BRITISH STANDARDNational forewordThis British Standard is the U
2、K implementation of EN 1243:2011. Itsupersedes BS EN 1243:1999 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/52, Adhesives.A list of organizations represented on this committee can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 p
3、urport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 72238 7ICS 83.180Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandar
4、ds Policy and Strategy Committee on 31 May 2011.Amendments issued since publicationDate Text affectedBS EN 1243:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1243 April 2011 ICS 83.180 Supersedes EN 1243:1998English Version Adhesives - Determination of free formaldehyde in amino and amido
5、formaldehyde condensates Adhsifs - Dtermination du formaldhyde libre dans les condensats de formaldhyde amino et amido Klebstoffe - Bestimmung des freien Formaldehydgehaltes in Amino- und Amido-Formaldehyd-Kondensaten This European Standard was approved by CEN on 10 March 2011. CEN members are bound
6、 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 application to the CEN
7、-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 Management Centre ha
8、s 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, Netherlands, Norway, P
9、oland, 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 any form and b
10、y any means reserved worldwide for CEN national Members. Ref. No. EN 1243:2011: EBS EN 1243:2011EN 1243:2011 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Principle 45 Reagents .46 Apparatus .57 Sampling .58 Procedure .59 Expression of results 610 Test re
11、port 6BS EN 1243:2011EN 1243:2011 (E) 3 Foreword This document (EN 1243:2011) has been prepared by Technical Committee 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 tex
12、t 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 this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsi
13、ble for identifying any or all such patent rights. This document supersedes EN 1243:1998. The main modifications regarding the previous version are in the Foreword, Normative References and Clause 4. SAFETY STATEMENT Persons using this document should be familiar with the normal laboratory practice,
14、 if applicable. This document does not purport to 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 STATEMENT It is unde
15、rstood that some of the material permitted in this standard may have negative environmental impact. As technological advantages 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 sho
16、uld 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, Belgium, Bulgaria, Croatia, Cypr
17、us, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 1243:2011EN 1243:2011 (E) 4 1 S
18、cope This European Standard specifies a method for the determination of the free formaldehyde content in amino and amido-formaldehyde condensate adhesives. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the
19、 edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 923:2005+A1:2008, Adhesives Terms and definitions EN 1067, Adhesives Examination and preparation of samples for testing EN ISO 1042:1999, Laboratory glassware One-mark
20、 volumetric flasks (ISO 1042:1998) EN ISO 3696:1995, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) EN ISO 15605, Adhesives Sampling (ISO 15605:2000) EN ISO 385:2005, Laboratory glassware Burettes (ISO 385:2005) ISO 648:2008, Laboratory glassware Single-volume pip
21、ettes (ISO 648:2008) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 923:2005+A1:2008 and the following apply. 3.1 free formaldehyde percentage (m/m) of unreacted formaldehyde in the product 4 Principle Reaction of the free formaldehyde with sodium su
22、lphite, in the presence of a measured excess of acid, in accordance with the reaction: CH2O + Na2SO3+ H2O CH2(OH)SO3Na + NaOH and alkaline titration of the unreacted excess acid. The acid-sulphite mixture provides an essentially neutral buffered system which prevents hydrolysis of condensed formalde
23、hyde. A reaction temperature close to 0 C helps to ensure the absence of side reactions. 5 Reagents 5.1 Hydrochloric acid, aqueous 0,5 M standard volumetric solution. NOTE Sulphuric acid 0,25 M can be used as an alternative. BS EN 1243:2011EN 1243:2011 (E) 5 5.2 Sodium sulphite, aqueous 1 M solution
24、. 5.3 Hydrochloric acid, aqueous 0,1 M solution in sodium sulphite. The solution shall be freshly prepared by mixing 80 ml of sodium sulphite solution (5.2) with 20 ml of hydrochloric acid 0,5 M solution (5.1). NOTE Sulphuric acid can be used as an alternative. 5.4 Sodium hydroxide, aqueous 0,1 M st
25、andard volumetric solution. 5.5 Dimethylsulphoxide, aqueous 50 % v/v solution, or other solvents such as ethyleneglycol. NOTE When using a solvent different from dimethylsulphoxide, preliminary comparative tests should be carried out to check possible side reactions. 5.6 Thymolphthalein, 0,1 % m/v s
26、olution in ethanol 5.7 Deionized or distilled water, grade 3 as specified in EN ISO 3696:1995. 6 Apparatus 6.1 Ordinary laboratory apparatus All volumetric glassware shall be class A, conforming to EN ISO 385:2005, ISO 648:2008 or EN ISO 1042:1999 as appropriate. 6.2 Analytical balance, accurate to
27、within 0,1 g. 6.3 Conical flask, capacity 300 ml. 6.4 Ice and water bath. 7 Sampling Take a significant sample of the adhesive to be tested in accordance with EN ISO 15605. Homogenize as described in EN 1067. 8 Procedure 8.1 Disperse solid adhesives in water (5.7) at 50 % m/m and carry out the analy
28、sis within 2 h. Where the solid adhesive is a formulated type (with fillers and acid catalyst), neutralize the dispersion with sodium hydroxide (5.4) before the analysis. The neutralization of formulate adhesive dispersion shall be done in the following way: Weight the amount of dispersion to analys
29、e and add sodium hydroxide (5.4) till pH 7,0 0,2 and record the volume used (Vx). Throw away the sample. Weigh the same amount of another sample of dispersion, add the volume of sodium hydroxide Vxand proceed as described in 8.2, 8.3 and 8.4. 8.2 Weigh, to the nearest 0,1 g, in a 300 ml conical flas
30、k (6.3) 5 g of liquid adhesive or dispersion (8.1); add 50 ml of dimethylsulphoxide solution (5.5) previously cooled and put the flask in the ice and water bath (6.4) for 20 min (internal temperature 5 C). BS EN 1243:2011EN 1243:2011 (E) 6 8.3 Add rapidly, within 5 s, and whilst stirring, 30 ml of h
31、ydrochloric acid 0,1 M solution in sodium sulphite (5.3) previously cooled in the ice and water bath (6.4); wait 5 min to ensure complete reaction of the formaldehyde with sulphite; add 1 ml of thymolphthalein solution (5.6) and titrate immediately (in less than 1 min) the excess of acid with the so
32、dium hydroxide 0,1 M solution (5.4) to the blue colour change. Record the volume, V1, of the sodium hydroxide solution used, in millilitres. NOTE A potentiometric titration can be used if the temperature and the time conditions are respected. 8.4 Carry out a blank test under the same conditions, but
33、 without the adhesive, and note the volume V2, in millilitres, of sodium hydroxide solution used. NOTE If the difference V2- V1is lower than 3 ml, the analysis should be repeated weighing a larger quantity of adhesive (i.e. 10 g). 9 Expression of results The free formaldehyde content shall be calcul
34、ated by the following formula: Free formaldehyde % = m3,002 M )V(V12where V1is the volume, in millilitres, of 0,1 M sodium hydroxide solution (5.4) used for the adhesive test; V2is the volume, in millilitres, of 0,1 M sodium hydroxide solution (5.4) used for the blank test; M is the molarity of sodi
35、um hydroxide solution (5.4); m is the mass, in grams, of the adhesive test portion. NOTE For the solid adhesives “m“ is of the test portion (50 % dispersion). 10 Test report The test report shall include: a) reference to this European Standard, i.e EN 1243; b) the type and designation of the adhesiv
36、e tested; c) the result of the test expressed in accordance with Clause 9; d) any modification to the procedure described and any circumstances affecting the result; e) date of the test. This page deliberately left blankBSI is the independent national body responsible for preparing British Standards
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