BS EN ISO 9020-1998 (1999) BS 6782-7-1996 PDF

Full title and description

STB BS EN ISO 9020-1998 (1999) / BS 6782-7:1996 — National adoption record that identifies the British implementation (BS) and European adoption (EN) of ISO 9020 (original ISO 9020:1994 with Corrigendum 1:1996). The standard specifies a sodium‑sulfite titrimetric method for the determination of free (unreacted) formaldehyde content in amino (aminoplast) resins used as binders for paints and varnishes. The listing references the BS series method (BS 6782‑7:1996) that was renumbered and incorporated into the EN/ISO publication and later adopted as an STB record (national publication/adoption in 1999).

Abstract

This standard defines a laboratory titrimetric procedure in which free formaldehyde and related semiacetals are converted to hydroxymethane sulfonate by reaction with excess sodium sulfite at low temperature; the excess sulfite is titrated with iodine, and the hydroxymethane sulfonate is subsequently decomposed and the liberated sulfite titrated to determine the free‑formaldehyde content. The method applies to amino resins (e.g., urea‑formaldehyde and melamine‑formaldehyde) and certain furan resins, and it was developed for quality control and regulatory testing of binder materials used in paints and varnishes.

General information

• Status: Withdrawn / superseded (national adoption record from 1999; original ISO withdrawn and replaced by a later ISO/EN standard).
• Publication date: ISO origin: ISO 9020 published February 1994 (ISO 9020:1994) with Technical Corrigendum 1 (1996). EN/BS adoption: EN ISO 9020 published 1998; STB adoption recorded 1999; BS 6782‑7 edition referenced: 1996.
• Publisher: ISO (origin), adopted/published by CEN/BSI for EN/BS versions; national STB record for 1999 adoption.
• ICS / categories: 87.060.20 — Binders for paints and varnishes (paints and varnishes industry test methods and raw‑material testing).
• Edition / version: ISO 9020:1994 (Edition 1) + Corr.1:1996; EN ISO 9020:1998 (BS adoption around 1998/1999); related BS designation BS 6782‑7:1996 (method prior to renumbering).
• Number of pages: Original ISO text: 4 pages (ISO edition). Published EN/BS documents vary by publisher (typically 6–14 pages depending on national forewords and incorporation of corrigenda).

Scope

Specifies a laboratory titrimetric method for determining the content of free (unreacted) formaldehyde in amino resins used as binders in paints and varnishes. The method is applicable to resins produced by polycondensation of urea or melamine with formaldehyde and to certain furan resins (from furfuryl alcohol and formaldehyde) when not further modified. It is not intended for some modified resins and is distinct from methods for coated fabrics or other materials covered by different standards. The ISO method was later consolidated into a broader standard covering multiple resin types.

Key topics and requirements

• Analytical principle: sodium‑sulfite addition at 0 °C forming hydroxymethane sulfonate, iodine titration of excess sulfite, decomposition and back‑titration to quantify free formaldehyde.
• Applicability: urea‑formaldehyde and melamine‑formaldehyde resins; selected furan resins (subject to limitations noted in the text).
• Precision and procedural controls: temperature control (near 0 °C), correct reagent concentrations, and procedural steps for complete conversion and accurate titration.
• Limitations: not suitable for resins that have been modified (for example phenol‑modified furan resins) or for matrices outside the scope; alternative ISO methods apply for other resin types.
• Traceability: references laboratory glassware and reagent standards; typical references to laboratory water quality and burette/pipette requirements used in titrimetric procedures.
• Regulatory relevance: used for quality control, product specifications, and compliance where free‑formaldehyde limits are specified for binder products.

Typical use and users

Used by paint, varnish and adhesive manufacturers for raw‑material QC; by contract and in‑house chemical laboratories performing binder analysis; by standards bodies and test houses verifying compliance with product specifications or regulatory limits on free formaldehyde; and by R&D groups developing or reformulating amino resin systems where control of residual formaldehyde is important.

Related standards

ISO 9020:1994 (original), ISO 9020:1994/Cor 1:1996 (corrigendum); superseded/replaced by ISO 11402:2004 (Phenolic, amino and condensation resins — determination of free‑formaldehyde content — which consolidates methods), and by the corresponding EN/BS adoptions (for example BS EN ISO 11402:2005). It is also associated with the BS 6782 series of test methods for binders for paints (other parts cover acid value, hydroxyl value, saponification value, etc.).

Keywords

binders; paints; varnishes; amino resins; urea‑formaldehyde; melamine‑formaldehyde; free formaldehyde; sodium sulfite titration; titrimetric method; BS 6782; EN ISO 9020; ISO 9020; formaldehyde determination.

FAQ

Q: What is this standard?

A: It is the test method originally published as ISO 9020:1994 (with corrigendum 1996) and adopted as EN ISO 9020 (late 1990s) and associated with the British method BS 6782‑7:1996; it prescribes a sodium‑sulfite titrimetric procedure to measure free formaldehyde in amino resins for paints and varnishes.

Q: What does it cover?

A: The standard covers sample preparation and a step‑wise titrimetric procedure at low temperature to quantify free formaldehyde (including semiacetals) present in amino and certain furan resins used as binders. It gives procedural details, reagent requirements and limitations of applicability.

Q: Who typically uses it?

A: Chemical laboratories in the coatings and adhesives industry, manufacturers performing quality control on binder products, independent testing houses and regulatory or standards organizations interested in measuring residual formaldehyde in resin materials.

Q: Is it current or superseded?

A: The ISO 9020 method has been withdrawn and consolidated into a later standard (ISO 11402:2004) and the corresponding EN/BS adoptions (for example BS EN ISO 11402:2005). National adoptions that referenced EN ISO 9020 in the late 1990s (including the STB record in 1999 and BS 6782‑7:1996) are therefore considered superseded by the later ISO/EN documents.

Q: Is it part of a series?

A: Yes. In the British system it was part of the BS 6782 series of binder test methods (other parts address acid value, hydroxyl value, saponification value, etc.). In the international/EU system it was an EN/ISO test method within the group of standards for binders for paints and varnishes.

Q: What are the key keywords?

A: binders, amino resins, free formaldehyde, sodium sulfite, titration, paints and varnishes, BS 6782, EN ISO 9020, ISO 9020.