ISO 25761:2008
(Main)Plastics — Polyols for use in the production of polyurethanes — Determination of basicity (total amine value), expressed as percent nitrogen
Plastics — Polyols for use in the production of polyurethanes — Determination of basicity (total amine value), expressed as percent nitrogen
The method specified in ISO 25761:2008 measures the basic constituents in polyols that are soluble in glacial acetic acid and reactive with perchloric acid. Samples containing 0,3 % to 10 % of nitrogen have been evaluated by this method. The method is applicable to polyether polyols and polyether polyol blends that are used in polyurethane reactions. The results are measures of batch-to-batch uniformity and may be used to estimate reactivity in polyurethane reactions.
Plastiques — Polyalcools utilisés pour la production de polyuréthannes — Détermination de la basicité (valeur totale d'amines) en pourcentage d'azote
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 25761
First edition
2008-05-15
Plastics — Polyols for use in the
production of polyurethanes —
Determination of basicity (total amine
value), expressed as percent nitrogen
Plastiques — Polyalcools utilisés pour la production de
polyuréthannes — Détermination de la basicité (valeur totale d'amines)
en pourcentage d'azote
Reference number
ISO 25761:2008(E)
©
ISO 2008
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ISO 25761:2008(E)
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ii © ISO 2008 – All rights reserved
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ISO 25761:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope .1
2 Normative references .1
3 Terms and definitions .1
4 Principle.2
5 Sampling.2
6 Interference .2
7 Reagents.2
8 Procedure .3
9 Expression of results .3
10 Precision and bias .4
11 Test report .5
Annex A (informative) Determination of the factor F for 0,1 mol/l perchloric acid in acetic acid.6
Bibliography .7
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ISO 25761:2008(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 25761 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting
materials.
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ISO 25761:2008(E)
Introduction
Polyurethanes are produced by the catalysed reaction of isocyanates with polyols. The basicity of the polyol
employed affects the rate of reaction and speed of cure of the product. It is therefore necessary to determine
the basicity in order to predict reactivity and monitor product quality.
© ISO 2008 – All rights reserved v
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INTERNATIONAL STANDARD ISO 25761:2008(E)
Plastics — Polyols for use in the production of
polyurethanes — Determination of basicity (total amine value),
expressed as percent nitrogen
SAFETY STATEMENT — Persons using this document should be familiar with normal laboratory
practice, if applicable. This document does not purport to address all of the safety concerns, 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 requirements.
1 Scope
1.1 The method specified in this International Standard measures the basic constituents in polyols that are
soluble in glacial acetic acid and reactive with perchloric acid. Samples containing 0,3 % to 10 % of nitrogen
have been evaluated by this method. The method is applicable to polyether polyols and polyether polyol
blends that are used in polyurethane reactions. The results are measures of batch-to-batch uniformity and
may be used to estimate reactivity in polyurethane reactions.
1.2 It is also permissible to express the results in equivalents of base per gram of sample.
1.3 This method is technically equivalent to that in ASTM D 6979-03.
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 amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 6353-1, Reagents for chemical analysis — Part 1: General test methods
ISO 6353-2, Reagents for chemical analysis — Part 2: Specifications — First series
ISO 6353-3, Reagents for chemical analysis — Part 3: Specifications — Second series
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
polyol
polymer based on ethylene oxide and/or propylene oxide which contains two or more hydroxyl groups
3.2
polyurethane
polymer prepared by the reaction of an organic di- or polyisocyanate with a compound containing two or more
hydroxyl groups
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ISO 25761:2008(E)
3.3
percent nitrogen
quantity of perchloric-acid-titratable base in a sample, expressed as a mass percentage of nitrogen
3.4
alkalinity
quantity of perchloric-acid-titratable base in a sample, expressed as mg of KOH/g of sample.
3.5
total amine value
quantity of perchloric-acid-titratable base in a sample, identified only as amines and expressed as mg of
KOH/g of sample
4 Principle
A test portion of the sample is dissolved in glacial acetic acid. The resulting single-phase solution is titrated at
room temperature to a potentiometric end point with a standardized solution of perchloric acid in acetic acid.
The result is reported as percent nitrogen or mg of KOH/g of sample.
5 Sampling
Draw samples from a well-mixed vessel into a thoroughly cleaned and dry borosilicate-glass container (soft-
glass containers are not acceptable). If sampling from a line or valve, flush the line thoroughly with the product
before starting to draw the sample. Seal the sample until analysis.
6 Interference
Any acidic or basic materials inadvertently introduced into the sample will cause errors in the analysis. Any
material capable of serving as a buffer may interfere with the analysis by obscuring the titration end point.
7 Reagents
Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of ISO 6353-1,
ISO 6353-2 and ISO 6353-3, as applicable. Other grades may be used, however, provided that it is first
determined that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the
determination.
Unless otherwise indicated, references to water shall be understood to mean grade 2 water as defined in
ISO 3696.
7.1 Glacial acetic acid.
...
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