Natural rubber latex concentrate - Centrifuged or creamed, ammonia-preserved types - Specifications
1Key Takeaways
This document gives specifications for natural rubber latex concentrate types which are preserved wholly or in part with ammonia and which have been produced by centrifuging or creaming.
2Expert Interpretation
This comprehensive analysis of the ISO 2004:2017 international standard for natural concentrated latex covers the technical requirements, test methods, and quality control points for centrifuged/pasteurized ammonia-preserved latex, including a comparison of core parameters such as dry rubber content, alkalinity, and mechanical stability for HA/LA/XA latexes.
Interpretation of the core content of the standard
The sixth edition of ISO 2004:2017 specifies the technical specifications for concentrated natural rubber latex, which is applicable to latex products that have been concentrated by centrifugation or paste-forming processes and fully or partially preserved with ammonia.
| Indicator | HA Type | LA Type | XA Type | Test Method |
|---|---|---|---|---|
| Dry Glue Content (min) | 60.0% | 60.0% | 60.0% | ISO 126 |
| Alkalinity(NH3) | ≥0.60% | ≤0.29% | 0.30-0.59% | ISO 125 |
| Mechanical stability(s) | ≥650 | ≥650 | ≥650 | ISO 35 |
Description of key test methods
1.
Measured by filtration through an 80μm mesh, the new standard lowers the upper limit from 0.03% to 0.02%, reflecting increased requirements for centrifuge separation efficiency.
2. Volatile Fatty Acid Number (VFA No.)
Measured using ISO 506, the requirement is ≤0.06 (negotiable to 0.70). This indicator directly affects the storage stability of latex.
Implementation Recommendations
- Raw Material Control: Ensure that the manganese content of fresh latex is ≤8mg/kg (ISO 7780)
- Process Optimization: The centrifuge speed and the amount of creaming agent should be adjusted according to the HA/LA type
- Quality Verification: Mechanical stability testing should be carried out 21-35 days after the latex matures