ISO 1183-1:2019

Overview

ISO 1183-1:2019 specifies standardized laboratory methods to determine the density of non-cellular plastics. It covers three validated procedures - the immersion method (Method A), the liquid pycnometer method (Method B) and the titration method (Method C) - and applies to void-free moulded or extruded objects as well as powders, flakes and granules. The standard defines apparatus, specimen preparation, test temperatures and calculation steps used to deliver traceable density results for plastics testing and quality control.

Key Topics

• Scope and applicability: Density determination for non-cellular plastics in void-free solid form (Method A), powders/granules/flakes (Method B) and any void-free form via titration (Method C).
• Apparatus and accuracy: Typical requirements include an analytical balance accurate to ±0.1 mg, pycnometer with overflow capillary, thermostatic liquid bath, desiccator (for powders), corrosion-resistant suspension wire (≤0.5 mm) and sinkers when needed.
• Immersion liquids and handling: Use distilled or de‑ionized water or suitable certified liquids; wetting agents limited to ≤0.1 % to reduce entrapped air. The liquid must not affect the specimen.
• Test conditions: Temperatures commonly specified at 23 °C ±2 °C (or 27 °C ±2 °C), with tighter tolerances (±0.5 °C) when measuring immersion liquid density.
• Calculation principles: Density is calculated from specimen mass in air and apparent mass when immersed, using the measured or certified density of the immersion liquid; methods account for sinkers and buoyancy corrections.
• Conditioning and reproducibility: Specimens are conditioned per ISO 291 when required; density can depend on specimen preparation and should be defined in material specifications.
• Quality elements: Minimum of three specimens recommended; Clause 6 addresses correction for air buoyancy. The 2019 edition revised the buoyancy correction.

Applications

ISO 1183-1:2019 is used by:

• Plastics manufacturers for product release testing and batch verification.
• Quality control and testing laboratories to provide consistent, traceable density data.
• R&D teams monitoring formulation or processing effects on material density.
• Material specifiers and purchasers verifying supplier claims.
• Recycling and sorting operations that rely on density differences for separation.

Typical practical uses include verifying composition/uniformity, detecting processing-induced structural changes, and supporting material identification and sorting workflows.

Related Standards

• ISO 291 - Plastics: standard atmospheres for conditioning and testing
• ISO 472 - Plastics: vocabulary
• Other parts of the ISO 1183 series (for alternative density/determination methods)

Keywords: ISO 1183-1:2019, density of plastics, immersion method, liquid pycnometer, titration method, non-cellular plastics, plastic density testing, buoyancy correction, specimen conditioning.