ISO 126:2005

Overview

ISO 126:2005 is an international standard established by the International Organization for Standardization (ISO) that specifies a precise method for determining the dry rubber content (DRC) of natural rubber latex concentrate. This standard is essential for quality control and ensures consistency in the evaluation of natural rubber latex, specifically from Hevea brasiliensis. It provides standardized procedures to accurately measure the dry rubber percentage, which is a critical parameter affecting rubber processing and product quality.

The method described in ISO 126:2005 is applicable to natural rubber latex concentrates preserved with ammonia and/or other preservatives and concentrated by various processes. However, it is not suitable for latex preserved with potassium hydroxide, latex from sources other than Hevea brasiliensis, vulcanized or compounded latex, artificial rubber dispersions, or synthetic rubber latices.

Key Topics

• Scope and Limitations
  The standard outlines the scope clearly, restricting its use to natural rubber latex concentrate and excluding specific types based on preservation methods or latex origin.

• Method Principle
  The determination involves diluting the latex concentrate to a specific solids content, acidifying it to coagulate the rubber, collecting the coagulated rubber into sheets, drying to a controlled temperature (70 °C ± 5 °C), and weighing to calculate the dry rubber content.

• Sample Preparation and Reagents
  Detailed instructions are provided for preparing reagents, including aqueous acetic acid solutions and ethanol for coagulation and washing. The method demands the use of analytical-grade reagents and distilled or equivalent purity water.

• Testing Apparatus
  Common laboratory equipment such as precision balances and drying ovens are used, with specifications on preferred capsule materials to avoid chemical interference.

• Operational Steps
  Including sample dilution, acid addition based on preservation type (ammonia or potassium hydroxide), coagulation, washing, pressing, drying, and repeated weighing until consistent results are obtained.

• Quality Assurance
  The procedure includes performing duplicate tests and mandates result agreement within 0.1% mass. The standard also incorporates fidelity metrics derived from interlaboratory testing to ensure the method’s repeatability and reproducibility.

• Reporting
  The test report must include the reference to ISO 126:2005, sample identification, average dry rubber content with precision, drying temperature, any anomalies, and deviations from prescribed methods.

Applications

The ISO 126:2005 method is primarily used by rubber producers, quality control laboratories, and manufacturers involved in:

• Natural Rubber Production - Ensuring consistent dry rubber content in latex concentrates before processing.
• Quality Control in Rubber Industry - Verifying latex quality parameters critical for rubber goods manufacturing such as tires, gloves, and industrial rubber products.
• Research and Development - Evaluating latex samples for new formulations or preservative impacts.
• Trade and Compliance - Providing standardized results for contractual agreements and compliance with quality specifications.

This method enables accurate assessment of latex solids content, ensuring optimal processing conditions and product performance.

Related Standards

To complement ISO 126:2005, several related ISO standards support latex quality assessment and sampling:

• ISO 123 - Latex of Natural Rubber - Sampling
  Provides standardized sampling procedures critical to ensuring representative testing materials for dry rubber content determination.

• ISO 124 - Latex of Natural Rubber - Determination of Total Solids Content
  Used in conjunction with ISO 126 for assessing total solids, a parameter necessary before DRC measurement.

• ISO/TR 9272 - Rubber and Rubber Products - Evaluation of Test Method Precision
  Offers guidance on interpreting repeatability and reproducibility data, supporting the fidelity assessment of ISO 126’s method.

Together, these standards form a comprehensive framework for accurate and reliable analysis of natural rubber latex concentrates.

Keywords: ISO 126:2005, natural rubber latex concentrate, dry rubber content, latex DRC determination, rubber testing standard, latex quality control, Hevea brasiliensis latex, rubber industry standards, latex coagulation method, ISO rubber testing