1、July 2011 Translation by DIN-Sprachendienst.English price group 7No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 83
2、.180!$sAy“1803086www.din.deDDIN EN 1245Adhesives Determination of pHEnglish translation of DIN EN 1245:2011-07Klebstoffe Bestimmung des pH-WertesEnglische bersetzung von DIN EN 1245:2011-07Adhsifs Dtermination du pHTraduction anglaise de DIN EN 1245:2011-07SupersedesDIN EN 1245:1998-12www.beuth.deDo
3、cument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.9 06.11 DIN EN 1245:2011-07 2 A comma is used as the decimal marker. National foreword This standard has been prepared by Technical Committee CEN/TC 193 “Adhesives” (Secretariat: AENOR, Spain). The
4、 responsible German bodies involved in its preparation was the Normenausschuss Kunststoffe (Plastics Standards Committee), Working Committee NA 054-04-06 AA Klebstoffe Terminologie; physikalisch-chemische Prfungen. The DIN Standard corresponding to the International Standard referred to in this docu
5、ment is as follows: EN ISO 3696 DIN ISO 3696 Amendments This standard differs from DIN EN 1245:1998-12 as follows: a) the title of the standard has been modified; b) the foreword now includes a “Safety Statement” and an “Environmental Statement”; c) Clause 2 “Normative references” has been updated:
6、EN ISO 15605, Adhesives Sampling (ISO 15605:2000) has been added; EN 1066, Adhesives Sampling has been deleted; EN 923:2005+A1:2008 and EN ISO 3696:1995 are now dated references; d) Clause 5 “Safety” has been deleted; e) the standard has been editorially revised. Previous editions DIN 68141: 1969-10
7、, 1995-08 DIN EN 1245: 1998-12 National Annex NA (informative) Bibliography DIN ISO 3696, Water for analytical laboratory use Specification and test methods EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1245 April 2011 ICS 83.180 Supersedes EN 1245:1998English Version Adhesives - Determinatio
8、n of pH Adhsifs - Dtermination du pH Klebstoffe - Bestimmung des pH-Wertes 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 giving this European Standard the status of a national
9、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 official versions (English, French, German). A version
10、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 bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
11、 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 Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROP
12、EN 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 1245:2011: EEN 1245:2011 (E) 2 Contents Page Foreword 31 Scope 42 Normativ
13、e references 43 Terms and definitions .44 Principle 45 Apparatus .46 Reagents .57 Sampling .58 Procedure .69 Expression of results 710 Test report 7DIN EN 1245:2011-07 EN 1245:2011 (E) 3 Foreword This document (EN 1245:2011) has been prepared by Technical Committee CEN/TC 193 “Adhesives”, the secret
14、ariat 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 withdrawn at the latest by October 2011. Attention is dra
15、wn 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 1245:1998. The main modifications regarding the previous version are in th
16、e Title, Foreword, 8.4 and Normative References. 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. It is the responsibility of the
17、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 advantages lead to acceptable alte
18、rnatives 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/CENELEC Internal Regulations, the
19、 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, Lithuania, Luxembourg, Malta, Netherl
20、ands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DIN EN 1245:2011-07 EN 1245:2011 (E) 4 1 Scope This European Standard specifies a method for the determination by electrometry of the pH of adhesives, their basic constituents and related
21、products using a pH meter equipped with a glass and silver reference combined electrode. This standard is applicable to products supplied in an aqueous medium, and of known concentration, and to products which can be dissolved, dispersed or suspended in water. It is not applicable to adhesives that
22、react with water. NOTE The accuracy of the method decreases at pH values above 11. 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
23、 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 3696:1995, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) EN ISO 15605, Adhes
24、ives 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 and the following apply. 3.1 pH log 1/ H+ where H+ is the hydrogen ion concentration of the test sample in moles per cubic decimetres (mol/dm3) 4 Principle
25、 Measurement of the potential difference existing between a glass electrode and a reference electrode immersed in the aqueous dispersion maintained at the specified test temperature, and reading of this difference expressed in pH units, directly on the pH meter scale. 5 Apparatus 5.1 pH meter, with
26、input impedance of at least 1012, a resolution of 0,01 pH unit, and equipped for temperature compensation. 5.2 Combined electrode, a glass electrode surrounded concentrically by a silver reference electrode. The reference electrolyte (6.3) is kept in electrical contact with the sample by a porous di
27、aphragm. The glass electrode used shall be one recommended by the manufacturer as suitable over the pH range to be encountered. Maintain the electrodes in accordance with the manufacturers instructions. DIN EN 1245:2011-07 EN 1245:2011 (E) 5 NOTE 1 While separate electrodes can be used, it is recomm
28、ended that they are replaced with combined electrodes. For ecological reasons, silver/silver chloride electrodes are preferred to mercury/calomel electrodes. NOTE 2 The electrodes function linearly between pH 0 and the appearance of the alkaline error, which, depending on the sodium ion concentratio
29、n, usually does not begin until the pH exceeds 11. 5.3 Thermostatically controlled water bath, controlled to within 1 C of the specified test temperature which shall be stated. NOTE In the absence of specific temperature requirements, 23 C is the preferred temperature. 5.4 Thermometer, graduated to
30、0,1 C. 6 Reagents 6.1 Deionised or distilled water, complying with EN ISO 3696:1995, grade 3. 6.2 Commercially available analytical grade buffer solutions of known pH shall be used. In the absence of commercial buffer solutions, prepare the following solutions using only reagents of known analytical
31、 grade and carbon dioxide free distilled water, or water of equivalent purity (grade 3 as defined in EN ISO 3696:1995). 6.2.1 Buffer solution of pH 7 Dissolve 3,40 g of potassium dihydrogen phosphate (KH2PO4) and 3,55 g of disodium hydrogen phosphate (Na2HPO4) in water and dilute to 1 dm3in a volume
32、tric flask. The pH of this solution is 6,87 at 23 C. 6.2.2 Buffer solution of pH 4 6.2.2.1 Dissolve 10,21 g of potassium hydrogen phthalate (KOOC-C6H4-COOH) in water and dilute to 1 dm3in a volumetric flask. The pH of this solution is 4 at 23 C. 6.2.2.2 The solution shall be stored in a glass or pol
33、yethylene vessel that is resistant to chemicals. After one month the solution shall be replaced. 6.2.3 Buffer solution of pH 9 6.2.3.1 Dissolve 3,814 g of sodium tetraborate decahydrate (Na2B4O710 H2O) in water and dilute to 1 dm3in a volumetric flask. The pH of this solution when freshly prepared i
34、s 9,20 at 23 C. 6.2.3.2 The solution shall be stored in a glass or polyethylene vessel that is resistant to chemicals and fitted with a soda-lime carbon dioxide trap. After one month the solution shall be replaced. NOTE Alkaline buffer solutions are unstable; they absorb carbon dioxide from the atmo
35、sphere. Where an alkaline buffer has been used for calibration, the accuracy may be verified by means of the buffer solution of pH 4. 6.3 Reference electrolyte, 3 mol/dm3solution of potassium chloride saturated with silver chloride. 7 Sampling Take a significant sample of the adhesive to be tested,
36、in accordance with EN ISO 15605, and prepare it, in accordance with EN 1067. DIN EN 1245:2011-07 EN 1245:2011 (E) 6 8 Procedure 8.1 General Reduction of thermal and electrical hysteresis effects, by ensuring that the temperatures of the test samples, electrodes, demineralised or distilled rinsing wa
37、ter and buffer solutions are as close to one another as possible. The temperatures of the test samples and buffer solutions shall not differ by more than 1 C. 8.2 Calibration Calibrate the pH meter in accordance with the manufacturers instructions. If these are not available, proceed as follows: 8.2
38、.1 Switch on the pH meter and allow the electronic circuit to stabilize. 8.2.2 Select two commercial buffer solutions (6.2). One at pH 7 corresponding to the zero point of the electrode and the other differing from the first by about 3 pH units and of a higher or lower pH in accordance with the samp
39、le being tested. Where commercial buffer solutions are not available use the appropriate prepared buffer solutions (6.2.1 and either 6.2.2 or 6.2.3). 8.2.3 Allow the temperature of the buffer solutions, the test sample and the electrode to equilibrate in the water bath (5.3) at the specified test te
40、mperature. Record the temperature using the thermometer (5.4) and adjust the temperature correction on the pH meter correspondingly. 8.2.4 Rinse the electrode with water (6.1) and then with the buffer solution of nominal pH 7, so that the liquid runs down the length of the electrode. 8.2.5 Introduce
41、 an adequate volume of the same buffer solution into a suitable clean, dry glass or plastic vessel and place in the water bath (5.3). Immerse the electrode in the buffer solution ensuring that the level of the reference electrolyte in the electrode remains about 5 cm higher than the level of the buf
42、fer solution (to prevent any contamination of the electrode). Stir gently and allow the reading to stabilize. Adjust the pH meter, using the zero point adjustment control, so that the reading corresponds to the pH of the buffer. Withdraw the electrode and discard the portion of that buffer solution.
43、 8.2.6 Rinse the electrode with water (6.1) followed by the chosen buffer solution as described in 8.2.4. NOTE Commercial buffer solution pH 10 may be available. 8.2.7 Immerse the electrode in a quantity of the chosen buffer solution as described in 8.2.5. Allow the reading to stabilize before adjus
44、ting the meter to the pH of the buffer solution using the gradient adjustment control and without touching the zero point control. Remove the electrode and wash with water (6.1). Discard the portion of the buffer solution. NOTE Ensure that the electrode gradient is in the range - 55,6 mV/pH to - 61,
45、5 mV/pH unit, i.e. that it is between 95 % and 103 % of the theoretical value (- 58,57 mV/pH unit at 23 C). If the electrode is outside this range refill with fresh reference electrolyte in accordance with the manufacturers instructions and repeat the calibration. 8.3 Measurement of the pH of the te
46、st sample 8.3.1 Mix the test sample thoroughly to ensure that it is homogeneous. NOTE Solid, water free or highly viscous adhesives shall be dissolved, dispersed or suspended in water in accordance with the manufacturers instructions or, if none are given, in the mass/mass ratio of 1:1. 8.3.2 Rinse
47、the electrode and measuring vessel with water (6.1) and dry with a clean soft tissue. Transfer an adequate volume into the vessel (an additional clean, dry vessel shall be used) and place it in the temperature controlled bath (5.3). Stir gently. DIN EN 1245:2011-07 EN 1245:2011 (E) 7 8.3.3 Immerse t
48、he electrode in the sample as described in 8.2.5 while maintaining the temperature at the required value. Allow the pH meter reading to stabilize and record the pH. 8.3.4 Clean the electrode by rinsing with water to remove any adhesive before it dries. 8.3.5 Repeat the operation (8.3.2 to 8.3.4) with a fresh portion of the test sample: a) if the new reading does not differ from the first by more than 0,1 pH unit, the determination is complete; b) if the readings differ by more than 0,1
