Overview
ISO 2027:1990 specifies quality and testing requirements for evaporated, preserved natural rubber latex concentrates (Hevea brasiliensis). It covers three product types-type HA (ammonia‑preserved), type KHS (potassium‑hydroxide preserved, ~73% total solids nominal) and type KLS (potassium‑hydroxide preserved, ~68% total solids nominal)-and applies to unvulcanized, non‑compounded evaporated concentrates. The standard updates the earlier 1978 edition and references a suite of ISO test methods for sampling and analysis.
Key topics and technical requirements
- Product scope: Only evaporated concentrates from Hevea brasiliensis; excludes centrifuged/creamed concentrates, compounded or vulcanized latex.
- Preservation and alkalinity:
- Type HA: preserved with ammonia (or ammonia plus other preservatives if declared); minimum alkalinity 0.60% (m/m) as NH3; no fixed alkali added.
- Type KHS/KLS: preserved with potassium hydroxide; nominal total solids cited (KHS ~73%, KLS ~68%) and minimum alkalinity values given as KOH (see standard for exact figures).
- Physical and chemical limits (examples from the specification):
- Total solids content: minimum values defined per type (see ISO 124 for determination).
- Coagulum content: maximum 0.05% (m/m) (ISO 706).
- Sludge content: maximum 0.40% (m/m) (ISO 2005).
- Manganese content: limits specified (e.g., 8 mg/kg of total solids) (ISO 7780).
- Volatile fatty acid (VFA) number: subject to agreement but not to exceed 0.20 (ISO 506).
- Organoleptic checks: colour-no pronounced blue or grey; odour-no pronounced putrefaction after neutralizing ammonia with boric acid.
- Testing and sampling: Sampling per ISO 123; dry rubber content per ISO 126; other referenced test methods listed in the standard.
Practical applications and users
ISO 2027 is used by:
- Natural rubber latex producers for product specification and quality control.
- Laboratory analysts performing acceptance testing and production QA.
- Rubber product manufacturers and compounders who require consistent concentrate properties for downstream processing (dipping, foam, adhesives).
- Procurement, regulatory agencies and import/export bodies verifying compliance with supplier declarations.
- R&D teams comparing formulations or evaluating preservative effects.
Adopting ISO 2027 helps ensure consistent physical/chemical quality, reduces processing variability, and supports trade by providing a common specification language.
Related standards
Key normative references cited by ISO 2027 include:
Keywords: ISO 2027, natural rubber latex, evaporated latex concentrate, latex specification, coagulum content, alkalinity, sludge content, VFA number, quality control.
