ISO 7142:2023

Overview

ISO 7142:2023 - Binders for paints and varnishes - Epoxy resins - General methods of test - specifies general test methods for epoxy resins and epoxy-resin solutions intended as binders for paints and varnishes. It defines required tests, sampling reference, and the minimum content of test reports. The standard explicitly excludes epoxy esters.

Key topics and technical requirements

• Scope & applicability
  • Applies to epoxy resins used in paints, varnishes and similar products, including resin solutions used as binders.
  • Not intended for epoxy esters.
• Sampling
  • Requires a representative sample taken in accordance with ISO 15528 (sampling of paints, varnishes and raw materials).
• Mandatory test properties (Table 1)
  • Colour - ISO 4630 (Gardner) or ISO 6271 (platinum‑cobalt)
  • Viscosity - ISO 3219-2 or agreed methods (flow-time per ISO 2431 if used)
  • Non‑volatile matter - ISO 3251
  • Flash point - ISO 1523 or ISO 3679
  • Epoxy equivalent - ISO 3001
  • Hydroxyl value - normative Annex A (titrimetric method described)
  • Total chlorine - ISO 4615
  • Easily saponifiable chlorine - ISO 21627-2
  • Melting point - ISO 3146
  • Softening point - ISO 4625-1 or ISO 4625-2
• Annex A - Hydroxyl value
  • Provides reagents, apparatus and titration procedure to determine hydroxyl equivalent and express hydroxyl value (g KOH/kg).
  • Precision: repeatability ~10%, reproducibility ~20%.
• Test report content
  • Must include product ID, reference to ISO 7142:2023, test results and methods, deviations, anomalies and test dates.

Practical applications and users

ISO 7142:2023 is designed for practical quality control, specification and communication across the paint, coatings and resin supply chain. Typical users:

• Coating manufacturers and formulators verifying binder quality before production.
• Raw material suppliers specifying epoxy resin properties for commercial data sheets.
• QC/analytical labs performing standardized tests (epoxy equivalent, hydroxyl value, viscosity, colour, chlorine content, flash point).
• Procurement and specification engineers who need reproducible test methods to compare materials or enforce purchase specifications.

Using ISO 7142:2023 ensures consistent, comparable data on critical binder properties and supports regulatory, safety and performance assessments in coatings formulation.

Related standards

Commonly used normative references cited in ISO 7142:2023 include:

• ISO 15528 (sampling)
• ISO 3001 (epoxy equivalent)
• ISO 3251 (non‑volatile matter)
• ISO 3219-2 (rheology)
• ISO 4630 / ISO 6271 (colour)
• ISO 1523 / ISO 3679 (flash point)
• ISO 4615, ISO 21627-2 (chlorine content)
• ISO 3146, ISO 4625-1/2 (melting/softening point)

Keywords: ISO 7142:2023, epoxy resins, binders for paints and varnishes, test methods, hydroxyl value, epoxy equivalent, paint binder testing.