EN 13955:2002

Surface active agents - Determination of Krafft point and solubility of ionic surface active agents

This European Standard specifies a method for the determination of the solubility of ionic surface active agents in water as a function of concentration and temperature and for the determination of the Krafft point by graphical evaluation of the measurement results.
In the temperature range from 0 °C to 90 °C, the solubility is determined without any limitations if the viscosity of the solution does not exceed about 700 mPas.
At temperatures below 0 °C, determination is only possible if the solvent does not freeze.
The method is applicable both to pure surface active agents and to technical products optically clear and not unduly coloured solutions.
The solubility both of solid and liquid surface active agents and of aqueous solutions of surface active agents is determined by the method specified.

Grenzflächenaktive Stoffe - Bestimmung von Krafft-Punkt und Löslichkeit von ionischen grenzflächenaktiven Stoffen

Agents de surface - Détermination du point de Krafft et de la solubilité des agents de surface ioniques

La présente Norme européenne spécifie une méthode de détermination de la solubilité des agents de surface ioniques dans l'eau en fonction de la concentration et de la température et une méthode de détermination de la température du point de Krafft par évaluation graphique à partir de résultats de mesurage.
Dans le domaine de température allant de 0 °C à 90 °C, la solubilité est déterminée sans aucune limitation si la viscosité de la solution n'excède pas 700 mPa.s.
À des températures en dessous de 0 °C, la détermination est seulement possible si le solvant ne gèle pas.
La méthode est applicable à la fois aux agents de surface purs et aux produits techniques optiquement clairs et aux solutions pas trop colorées.
La méthode spécifiée détermine la solubilité à la fois des agents de surface solides et liquides et des solutions aqueuses d'agents de surface.

Površinsko aktivne snovi - Določevanje Krafftove točke in topnosti ionskih površinsko aktivnih snovi

General Information

• Status: Published
• Publication Date: 03-Dec-2002
• Withdrawal Date: 29-Jun-2003
• ICS: 71.100.40 - Surface active agents
• Technical Committee: CEN/TC 276 - Surface active agents
• Drafting Committee: CEN/TC 276/WG 2 - Methods of test
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 31-Oct-2024
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 13955:2003 - Surface active agents - Determination of Krafft point and solubility of ionic surface active agents

Overview

EN 13955:2002 is a European Standard developed by CEN that provides a precise method for determining the Krafft point and the solubility of ionic surface active agents (surfactants) in water. This standard is essential for quality control and research in industries where ionic surfactants play a critical role, such as detergents, cosmetics, pharmaceuticals, and chemical manufacturing. The method is applicable to both pure compounds and technical products with clear, lightly colored solutions.

Key Topics

• Krafft Point Determination
  The Krafft point is the specific temperature at which an ionic surfactant's solubility sharply increases, leading to micelle formation. EN 13955:2002 defines this point graphically by plotting solubility against temperature and identifying the intersection of distinct solubility curves. This critical temperature influences product formulation and stability.

• Solubility Measurement
  The standard details procedures for measuring the solubility of ionic surface active agents in the temperature range of 0 °C to 90 °C, with certain conditions for sub-zero temperatures (solvent must not freeze). It accounts for both liquid and solid surfactants and aqueous solutions, emphasizing conditions such as solution viscosity (below approximately 700 mPas) to ensure accurate measurement.

• Test Procedure and Apparatus
  The method involves gradually cooling a surfactant solution until cloudiness appears, then slowly heating it to the clearing temperature while continuously stirring. This approach ensures equilibrium and accurate observation at the solubility limit. The standardized test apparatus includes a thermostatically controlled test vessel, basket stirrer, precise thermometer, and stopper, following detailed dimensions and specifications for reproducibility.

• Graphical Analysis
  Solubility data collected at multiple concentrations are plotted to form a phase diagram that includes three distinct regions representing different states of the surfactant in solution. The Krafft point is identified at the intersection of solubility branches above and below the critical temperature.

• Precision and Reporting
  Repeatability is critical: duplicate measurements must be within 0.5 °C difference. The test report includes the surfactant concentrations, measured clearing temperatures, the derived Krafft point, testing date, and any deviations from the standard method.

Applications

• Detergent Formulation
  Understanding the Krafft point helps in selecting surfactants that remain soluble and effective under specific temperature conditions to optimize cleaning performance.

• Cosmetic and Pharmaceutical Products
  Precise solubility data enable formulation of stable emulsions and gels, ensuring product consistency and safety.

• Chemical Manufacturing Quality Control
  Regular testing ensures batch-to-batch consistency of ionic surfactants used as intermediates or additives.

• Research and Development
  Provides insight into surfactant behavior, aiding in the development of new surfactants with tailored solubility profiles and improved efficacy.

Related Standards

• EN ISO 3696 – Water for Analytical Laboratory Use: Specifies requirements for water purity used during surfactant solubility testing.
• ISO 383 – Laboratory Glassware: Defines interchangeable conical ground joints used in the test apparatus setup.

Adherence to EN 13955:2002 enables organizations to generate reliable, comparable data critical for performance evaluation and regulatory compliance in sectors utilizing ionic surface active agents. This standard supports accurate determination of solubility properties and the Krafft point, key parameters in surfactant chemistry and applications.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Grenzflächenaktive Stoffe - Bestimmung von Krafft-Punkt und Löslichkeit von ionischen grenzflächenaktiven StoffenAgents de surface - Détermination du point de Krafft et de la solubilité des agents de surface ioniquesSurface active agents - Determination of Krafft point and solubility of ionic surface active agents71.100.40Površinsko aktivna sredstvaSurface active agentsICS:Ta slovenski standard je istoveten z:EN 13955:2002SIST EN 13955:2003en01-februar-2003SIST EN 13955:2003SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13955December 2002ICS 71.100.40English versionSurface active agents - Determination of Krafft point andsolubility of ionic surface active agentsAgents de surface - Détermination du point de Krafft et dela solubilité des agents de surface ioniquesGrenzflächenaktive Stoffe - Bestimmung von Krafft-Punktund Löslichkeit von ionischen grenzflächenaktiven StoffenThis European Standard was approved by CEN on 23 October 2002.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2002 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13955:2002 ESIST EN 13955:2003

Graphical representation of the Krafft point.9SIST EN 13955:2003
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