Overview
ISO 1795:2017 specifies standardized procedures for the sampling of raw natural and raw synthetic rubber (bales, blocks or packages) and the preparative steps to produce representative test samples for chemical and physical testing. This fifth edition updates sampling selection, laboratory-sample handling and milling/homogenizing procedures used prior to determinations such as volatile-matter content, Mooney viscosity, plasticity retention index (PRI) and vulcanization characteristics.
Key topics and requirements
- Scope: Sampling of raw rubber in bales/blocks/packages and subsequent preparative procedures for testing.
- Sample selection: Number of bales representing a lot is to be agreed between customer and supplier; statistical plans (ISO 3951-2) can be applied.
- Laboratory sample: Preferred method is to remove outer wrapping and cut a cross-sectional slice from the middle of the bale. Mass of each laboratory sample: 350 g to 1 500 g, depending on tests.
- Storage: If not used immediately, store in a light‑proof, moisture‑proof container not more than twice the sample volume.
- Combined laboratory sample: Equal parts of each laboratory sample can be blended to form a representative combined sample for chemical tests and vulcanization characteristics (Clause 6.2).
- Natural rubber (NR) preparation:
- Homogenize 250 g ± 5 g by milling 6 passes (nip 1.69 mm ± 0.17 mm), rolls at room temperature; record initial/final mass for volatile-matter calculations.
- Cut test pieces from the homogenized sample for Mooney viscosity (ISO 289-1), PRI (ISO 2930), volatile matter (ISO 248-1) and vulcanization (ISO 1658).
- Synthetic rubber preparation:
- Use 250 g ± 5 g for volatile-matter testing (hot-mill or oven per ISO 248-1); when using thermogravimetric methods (ISO 248-2), take test samples directly from the laboratory sample.
- Mooney viscosity: preferred without milling (prepare test pieces per ISO 289-1). If milling required, 10 passes with nip 1.4 mm ± 0.1 mm at 50 °C ± 5 °C (special conditions for BR, EPDM, some NBRs are specified).
- Equipment & environmental conditions: Milling operations use a roll mill per ISO 2393; laboratory conditioning per ISO 23529. Users must follow normal laboratory safety and regulatory requirements.
Applications and users
ISO 1795:2017 is used by:
- Quality control laboratories in rubber manufacturing and compounding
- Raw-rubber suppliers and buyers for lot acceptance and dispute resolution
- Test laboratories preparing samples for chemical analyses (volatile matter), rheological tests (Mooney viscosity), PRI and vulcanization testing
- Inspectors and procurement teams implementing consistent raw material sampling procedures
Related standards
Commonly used alongside:
Keywords: ISO 1795:2017, raw rubber sampling, natural rubber, synthetic rubber, Mooney viscosity, plasticity retention index, volatile-matter content, homogenizing, milling, laboratory sample.
Open preview (PDF)Rubber, raw natural and raw synthetic — Sampling and further preparative procedures