EN 1241:1998

Adhesives - Determination of acid value

This standard specifies a method for determination of the acid value of adhesives, adhesive components, their basic constituents, and related products. In some cases, notably when unsaturated polyesters with free anhydrides are present, somewhat lower than theoretical acid values are found, due to the formation of acid esters which precipitate and, are therefore, not determined.

Klebstoffe - Bestimmung der Säurezahl

Diese Norm legt ein Verfahren zur Bestimmung der Säurezahl von Klebstoffen, deren Grundbestandteilen sowie bei verwandten Produkten fest. In einigen Fällen, namentlich in Anwesenheit ungesättigter Polyester mit freien Anhydridgruppen, werden etwas geringere als die theoretischen Säurezahlen gefunden und zwar infolge der Bildung von Säureestern, die sich ausscheiden und daher nicht erfaßt werden.

Adhésifs - Détermination de l'indice d'acidité

La présente norme spécifie une méthode pour la détermination de l'indice d'acidité des adhésifs des comoposants d'adhésifs, de leurs constituants de base et des produits connexes. Dans certains cas, particulièrement lorsque des polyesters non saturés avec des anhydrides libres sont présents, on trouve un indice d'acidité quelque peu inférieur à la valeur théorique, en raison de la formation d'esters acides qui précipitent et par conséquent, ne sont pas déterminés.

Lepila - Določevanje kislinskega števila

General Information

• Status: Published
• Publication Date: 17-Feb-1998
• Withdrawal Date: 30-Aug-1998
• ICS: 83.180 - Adhesives
• Technical Committee: CEN/TC 193 - Adhesives
• Drafting Committee: CEN/TC 193/WG 1 - General terminology - General physical and chemical tests
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 22-Oct-2020
• Completion Date: 23-Sep-2025
• Ref Project: SIST EN 1241:1999 - Adhesives - Determination of acid value

Overview

EN 1241:1998 (CEN) defines a standardized laboratory method for the determination of acid value in adhesives, adhesive components, their basic constituents, and related products. The standard ensures consistent measurement of acidity for quality control, specification compliance, and materials characterization. The published Slovenian adoption is listed as SIST EN 1241:1999.

Key topics and requirements

• Scope and applicability: Measurement applies to finished adhesives, intermediate components and raw constituents used in adhesive formulations.
• Standardized test method: The document specifies a reproducible laboratory procedure for determining the acid value, enabling comparable results across laboratories and suppliers.
• Sample considerations: Guidance covers representative sampling and treatment of adhesive samples to obtain reliable acidity measurements.
• Interferences and limitations: The standard notes important exceptions - for example, unsaturated polyesters containing free anhydrides can form acid esters that precipitate. In such cases, measured acid values may be lower than theoretical values because these precipitated esters are not determined by the method.
• Reporting and interpretation: Results are presented as acid value (mass of potassium hydroxide equivalent per unit mass) and should be interpreted in the context of formulation chemistry and known interferences.
• Quality assurance: Use of control samples and documented procedures is implied to maintain test accuracy and repeatability.

Applications

EN 1241:1998 is useful for:

• Adhesive manufacturers performing routine quality control and incoming materials inspection.
• Formulators and R&D teams characterizing raw resins, components, and reaction outcomes.
• Laboratories providing testing services for product certification, trade specifications, and regulatory compliance.
• Suppliers and purchasers verifying that adhesive materials meet contractual acid value requirements.
• Failure analysis where unexpected acidity can affect curing, stability, or bonding performance.

Who uses this standard

• Quality control chemists in adhesive and coating industries
• Materials scientists and polymer chemists
• Third‑party testing laboratories
• Procurement and specification engineers

Related standards

• Other CEN/ISO test methods for adhesives (viscosity, solids content, curing and mechanical tests) are commonly used alongside EN 1241 to provide a full assessment of adhesive properties.

Keywords: EN 1241:1998, acid value determination, adhesives testing, CEN standard, adhesive quality control, unsaturated polyesters, acid esters.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Klebstoffe - Bestimmung der SäurezahlAdhésifs - Détermination de l'indice d'aciditéAdhesives - Determination of acid value83.180LepilaAdhesivesICS:Ta slovenski
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