Overview
ISO 1598:1990 is an international standard developed by the International Organization for Standardization (ISO) that specifies a test method for determining the number of insoluble and visible particles in cellulose acetate plastics. This standard addresses the identification and counting of impurities and foreign particles with diameters greater than 0.15 mm, which remain insoluble when dissolved in a specific solvent mixture. It is essential for quality control and assurance in the plastics industry, especially for manufacturers and laboratories working with cellulose acetate.
The test involves dissolving a sample of cellulose acetate in a solvent blend of dichloromethane, methanol, and dimethylphthalate, followed by visual inspection and particle counting within a defined area. The standard ensures consistent and reliable detection of particulate contamination to maintain the purity and performance of cellulose acetate products.
Key Topics
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Scope and Application
Applicable to cellulose acetate materials with acetic acid content above 50%, free of additives that could interfere with testing. It determines visible insoluble particles, including all impurities and foreign bodies.
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Test Principle
Dissolution of the cellulose acetate test sample in a solvent mixture, followed by microscopic or visual examination of insoluble particles larger than 0.15 mm.
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Solvent Mixture Composition
- Dichloromethane (90 parts by volume)
- Methanol (10 parts by volume)
- Dimethylphthalate (added in a 3:1 ratio to the solvent mix)
The solvents used must be of analytical grade and free from visible particles.
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Sample Preparation
The cellulose acetate sample is ground to pass through a 710 µm sieve and dried; moisture content is determined according to ISO 585.
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Detection Method
Particles are counted in a glass container with a 25 mm square grid base, illuminated uniformly from below. A reference particle of 0.15 mm diameter is used for size comparison. All visible insoluble particles equal to or larger than this reference are counted.
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Result Expression
Results are reported as the number of insoluble particles per 100 grams of dry cellulose acetate, averaged over two determinations.
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Safety Precautions
Due to the use of hazardous solvents like dichloromethane and methanol, safety measures, including appropriate ventilation, protective equipment, and fire prevention, must be observed.
Applications
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Quality Control in Plastics Manufacturing
Ensuring the purity and consistency of cellulose acetate plastics by monitoring insoluble particles helps maintain product standards, reduce defects, and optimize processes.
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Research and Development
Analysis of particle contamination supports the development of higher-quality cellulose acetate formulations and processing techniques.
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Compliance and Certification
Manufacturers and testing labs use ISO 1598:1990 to demonstrate conformity with international quality and safety requirements for cellulose acetate materials.
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Process Improvement
Identification of insoluble foreign particles enables troubleshooting and refining manufacturing steps to minimize contaminants and improve product reliability.
Related Standards
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ISO 585 – Plastics – Cellulose acetate non-plasticized – Determination of moisture content
This standard details the method for measuring moisture in cellulose acetate samples prior to insoluble particle testing.
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ISO 565 – Control Sieves – Metallic woven wire cloth, perforated plates, and electroformed sheets – Nominal Dimensions of Apertures
Provides guidance on sample preparation related to particle size through sieving.
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ISO/TC 61 – Technical committee responsible for plastics standards including cellulose acetate testing methods.
Keywords: ISO 1598, cellulose acetate testing, insoluble particles determination, plastics quality control, solvent dissolution method, particle contamination analysis, polypropylene testing standards, dichloromethane methanol solvent mixture, dimethylphthalate, visible insoluble particles, international plastics standards, cellulose acetate impurities, ISO plastics standards.