1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 1240:2011Adhesives Determination ofhydroxyl value and/or hydroxylcontentBS EN 1240:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of E
2、N 1240:2011. Itsupersedes BS EN 1240:1998 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/52, Adhesives.A list of organizations represented on this committee can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 purport to include all
3、 the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 72237 0ICS 83.180Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strateg
4、y Committee on 31 May 2011.Amendments issued since publicationDate Text affectedBS EN 1240:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1240 April 2011 ICS 83.180 Supersedes EN 1240:1998English Version Adhesives - Determination of hydroxyl value and/or hydroxyl content Adhsifs - Dtermina
5、tion de la valeur hydroxyle et/ou de la teneur en hydroxyle Klebstoffe - Bestimmung der Hydroxylzahl und/oder des Hydroxylgehaltes This European Standard was approved by CEN on 10 March 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for
6、 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 Centre or to any CEN member. This European Standard exists in three
7、 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 the official versions. CEN members are the national standards bodi
8、es of Austria, Belgium, Bulgaria, Croatia, Cyprus, 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 United Kin
9、gdom. 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 by any means reserved worldwide for CEN national Members. Ref. No. EN 1240:2011: EBS EN
10、1240:2011EN 1240:2011 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Principles 45 Reagents .56 Apparatus .57 Procedures .58 Expression of results 69 Test report 7BS EN 1240:2011EN 1240:2011 (E) 3 Foreword This document (EN 1240:2011) has been prepared by
11、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 text or by endorsement, at the latest by October 2011, and conflicting national standards shall be wit
12、hdrawn 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 responsible for identifying any or all such patent rights. This document supersedes EN 1240:1998. The main
13、modifications regarding the previous version are in the Foreword, Normative References and 6.5. 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
14、 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 understood that some of the material permitted in this standard may have negative environmental impact. As t
15、echnological 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 should take care to carry out an appropriate disposal of the wastes, according to local regulation. Accordi
16、ng 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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy
17、, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 1240:2011EN 1240:2011 (E) 4 1 Scope This European Standard specifies a method to determine the hydroxyl value and/or the hydroxyl conte
18、nt of adhesives, adhesive components, their basic constituents and related products. This method can also be used to determine the hydroxyl value and/or the hydroxyl content of surface protection systems of concrete. 2 Normative references The following referenced documents are indispensable for the
19、 application of this document. For dated references, only the 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 sample
20、s for testing EN 1241, Adhesives Determination of acid value EN ISO 15528, Paints, varnishes and raw materials for paints and varnishes Sampling (ISO 15528:2000) EN ISO 1042:1999, Laboratory glassware One-mark volumetric flasks (ISO 1042:1998) EN ISO 3696:1995, Water for analytical laboratory use Sp
21、ecification 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 pipettes (ISO 648:2008) 3 Terms and definitions For the purposes of this document, the terms a
22、nd definitions given in EN 923:2005+A1:2008 and the following apply. 3.1 hydroxyl value number of milligrams of potassium hydroxide necessary to neutralize the acetic acid which will combine by acetylation with 1 g of the product under test 3.2 hydroxyl content mass fraction in percentage of hydroxy
23、l groups (-OH) contained in the product under test 4 Principles Acetylation of the hydroxyl groups is carried out by acetic anhydride on a pyridine solution of the product under test. The excess acetic anhydride is hydrolyzed by the addition of water and the resultant acetic acid titrated with aqueo
24、us potassium hydroxide solution. BS EN 1240:2011EN 1240:2011 (E) 5 5 Reagents 5.1 Acetic anhydride, analytical grade. 5.2 Pyridine, analytical grade. 5.3 Acetylation solution Add slowly, while mixing, 28 ml of acetic anhydride (see 5.1) to 200 ml of pyridine (see 5.2) and store in a dry atmosphere.
25、5.4 Water for analytical laboratory use, grade 3 as specified in EN ISO 3696:1995. 5.5 Phenolphthalein (mass concentration = 0,1 %) indicator solution Dissolve 0,1g of phenolphthalein, dilute to 100 ml in pyridine (see 5.2), and make this solution faintly pink by addition of potassium hydroxide solu
26、tion. 5.6 Potassium hydroxide, carbonate-free, 1 M aqueous solution. 6 Apparatus All volumetric glassware shall be class A, in accordance with EN ISO 385:2005, ISO 648:2008 or EN ISO 1042:1999 as appropriate. 6.1 Analytical balance, with a scale division of 0,1 mg. 6.2 Conical flask, capacity 250 ml
27、, with a ground glass stopper. 6.3 One-mark pipette, capacity 20 ml. 6.4 Water-cooled reflux condenser, length 50 cm, inside diameter approximately 9 mm, with ground glass joints to fit the flasks (see 6.2). It shall be fitted on its top with a guard tube containing anhydrous calcium chloride. 6.5 W
28、ater bath, controlled at 100 C. 6.6 Burette, capacity 50 ml, graduated in 0,05 ml. 6.7 Apparatus for potentiometric titration, optional or if necessary, e.g. for dark coloured solutions. 7 Procedures Take a sample of the product to be tested in accordance with EN ISO 15605. For surface protection sy
29、stems take a sample in accordance with EN ISO 15528. Examine and prepare this sample for testing in accordance with EN 1067 or EN ISO 15528 as appropriate. Weigh, to the nearest 1 mg, in a 250 ml conical flask (see 6.2) a test portion the mass of which is calculated from the expected hydroxyl value
30、or hydroxyl content by the following formulae: content hydroxyl5,8or valuehydroxyl280gramsin portion test = BS EN 1240:2011EN 1240:2011 (E) 6 NOTE 1 If the approximate hydroxyl content or the approximate hydroxyl value is not known, preliminary tests should be made. Add to the sample 20 ml of the ac
31、etylation solution (see 5.3) with a one-mark pipette (see 6.3) and some dry anti-bumping granules. NOTE 2 The anti-bumping granules are neutral. In case of doubt, the granules should be boiled with water and dried carefully. Fit the reflux condenser (see 6.4) to the conical flask and ensure the tigh
32、tness of the joint by moistening with some drops of pyridine (see 5.2). Place the flask containing the sample in water bath controlled at 100 C and reflux for 60 min. Remove the flask from the bath, cool by cold running water to approximately 20 C and add through the condenser 40 ml of water (see 5.
33、4). Mix thoroughly and cool again. NOTE 3 The reaction time can be reduced by adding a suitable catalyst for example by the addition of an acid like toluene-4-sulphonic acid to unsaturated polyester resins or basic catalysts like tertiary amines to other polyol compounds. Comparative tests should be
34、 carried out to demonstrate that equivalent values are obtained by the use of the specific catalyst when a reduced reaction time is applied. Rinse any product adhering to the inner surface of the condenser with water (see 5.4) into the flask. Dissolve any precipitate by addition of 30 ml of pyridine
35、 (see 5.2). Add five drops of phenolphthalein solution (see 5.5) and titrate with the aqueous potassium hydroxide solution (see 5.6) until the colour changes to pink or use a potentiometric apparatus (see 6.7) for the end point detection. Record the volume V1, in millilitres, of the potassium hydrox
36、ide solution used. Carry out a blank test under the same conditions with the acetylation solution (see 5.3) but without the test portion, and note the volume V2, in millilitres, of potassium hydroxide solution used. At least three tests shall be carried out. The mean value shall not differ by more t
37、han 0,1 % of the hydroxyl content or two units of the hydroxyl value. If this is not the case, further tests shall be carried out until the values of three consecutive tests fulfil the requirement. NOTE 4 The free acid groups which exist in the product are also neutralized by the potassium hydroxide
38、. Therefore, in the final calculation hydroxyl value and/or hydroxyl content an acid value of the product under test should be taken into account determined in accordance with EN 1241 separately. 8 Expression of results 8.1 Calculation of the hydroxyl value OHvFrom the three test results obtained, c
39、alculate the hydroxyl value OHvby the equation: V12VA+m)V(Vx M x 56,1=OH (1) where M is the molarity of the potassium hydroxide solution; V1 is the volume, in millilitres, of the potassium hydroxide solution (see 5.6) required for the determination; V2 is the volume, in millilitres, of the potassium
40、 hydroxide solution (see 5.6) required for the blank test; BS EN 1240:2011EN 1240:2011 (E) 7 Av is the acid valuedetermined in accordance with EN 1241; m is the mass, in grams, of the test portion. NOTE The value of (V2- V1) can be positive or negative. 8.2 Calculation of the percentage of hydroxyl
41、content (OH %) Calculate the hydroxyl content OH % from the hydroxyl value OHv(see 8.1) by following the equation: VVOH x0,03 =56,1OH x 1,7=%)(OH (2) 9 Test report The test report shall include: a) reference to this European Standard, i.e. EN 1240; b) complete identification of the sample; c) identi
42、fication of the end point detection used (indicator or potentiometry); d) test results, individual values and their mean; e) any operations not specified in this European Standard, or the document to which reference is made, and all incidents that may have affected the results; f) date of test. This
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