Gummi- och plastindustri

This document defines test methods and criteria for distinguishing intrinsically biodegradable plastic materials from those that are persistent. Biodegradability is inferred from biodegradation tests conducted under aerobic conditions, i.e. under the conditions typically found in most natural habitats. Plastics that undergo ultimate biodegradation under aerobic conditions in a manner similar to natural polymer materials are defined as biodegradable plastics. This document describes a method for distinguishing between non-biodegradable plastics, which do not biodegrade even when environmental conditions are favourable for biodegradation (including aerobic conditions), and biodegradable plastics, i.e. those that biodegrade upon contact with active microorganisms when environmental conditions are favourable for biodegradation.

The aim is to demonstrate ultimate aerobic biodegradability of plastic materials, i.e. the intrinsic potential for conversion to carbon dioxide, water and biomass by aerobic microorganisms in an oxygen-rich environment, which is representative of most natural environments.

The potential for biodegradation should be verified using alternative tests and criteria, if a deposition in a permanent anaerobic environment (e.g. deep subsurface environments, wetlands and swamps, anoxic zones in oceans and lakes) is expected.

NOTE          Currently, there are no methodologies or criteria available to verify accumulation due to the lack of biodegradation of plastics in such anaerobic habitats.

The plastic materials identified as intrinsically biodegradable following this document can be used in the design of products with a high risk of dispersion whenever the use of biodegradable components is searched by the designer. Intrinsically non-biodegradable components are not susceptible to biodegradation and therefore cannot be removed from the environment by the action of micro-organisms. This factor tends to increase the residence time of products in the environment. In addition, their eventual degradation, mainly due to abiotic factors, results in persistent fragments (microplastics).

The test scheme described in this document is not specific to any particular application. Rather, it is a framework methodology that can be used in different industries to identify biodegradable plastics that can be used to make different types of products and for different applications. For the characterisation and environmental assessment of products placed on the market containing plastics identified as biodegradable according to this document, reference is made to the specific product standards, where available. This document only deals with the definition of intrinsic biodegradability of plastic materials, without defining the hazard of the products, which requires a specific assessment that is beyond the scope of this document. The rate of biodegradation of a plastic object as a function of environmental conditions cannot be determined from this document. Therefore, this document is not sufficient to carry out an analysis of the ecological risk associated with the dispersal of products, as this requires an assessment of the intrinsic hazard, of the environmental fate, in addition to the assessment of biodegradability.

The methodology described in this document does not apply to applications covered by mandatory regulations.

This document specifies the dimensions, the method of sampling, the preparation of the test specimens and the conditions for performing the tensile test in order to determine the short-term tensile welding factor. A tensile test can be used in conjunction with other tests (e.g. bend, tensile creep, macro) to assess the performance of welded assemblies, made from thermoplastics materials. The test is applicable to welded semi-finished products made from thermoplastics materials filled or unfilled, but not reinforced, irrespective of the welding process used.

This document specifies a method for the determination of the viscosity number of dilute solutions of polyamides in certain specified solvents.

The method is applicable to the polyamides designated PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 and PA MXD6 as defined in ISO 16396-1, as well as to co-polyamides, compounds of polyamides and other polyamides that are soluble in one of the specified solvents under the specified conditions.

The method is not applicable to polyamides produced by anionic polymerization of lactams or produced with cross-linking agents; such polyamides are normally insoluble in the specified solvents.

The viscosity number is determined by the general procedure specified in ISO 1628-1:2024, observing the particular conditions specified in this document.

1.1 This document specifies conditions for the determination of the reduced viscosity (also known as viscosity number) and K-value of PVC resins. It is applicable to resins in powder form which consist of homopolymers of the monomer vinyl chloride and copolymers, terpolymers, etc., of vinyl chloride with one or more other monomers, but where vinyl chloride is the main constituent. The resins may contain small amounts of unpolymerized substances (e.g. emulsifying or suspending agents, catalyst residues, etc.) and other substances added during the course of the polymerization. This document is not applicable, however, to resins having a volatile-matter content in excess of 0,5 % ± 0,1 %, when determined in accordance with ISO 1269. In addition to this, it is not applicable to resins which are not entirely soluble in cyclohexanone.

1.2 The reduced viscosity and K-value of a particular resin are related to its molecular mass, but the relationship varies depending on the concentration and type(s) of other monomer(s) present. Hence, homopolymers and copolymers having the same reduced viscosity or K-value might not have the same molecular mass.

1.3 The values determined for reduced viscosity and K-value, for a particular sample of PVC resin, are influenced differently by the concentration of the solution chosen for the determination. Hence the use of the procedures described in this document only gives values for reduced viscosity and K-value that are comparable when the concentrations of the solutions used are identical.

1.4 Limiting viscosity number is not used for PVC resins.

1.5 The experimental procedures described in this document can also be used to characterize the polymeric fraction obtained during the chemical analysis of a PVC composition. However, the values calculated for the reduced viscosity and K-value in these circumstances might not indicate the actual values for the resin used to produce the composition because of the impure nature of the recovered polymer fraction.

IThis part of ISO 1628 defines particular conditions for determining the reduced viscosity (also known as viscosity number) and intrinsic viscosity of polyethylenes and polypropylenes at elevated temperatures (135 °C – 160 °C) in dilute solution.

The viscosity of polymer solutions can be affected by fillers or additives present in the sample. The value of a reduced viscosity determined by this method can therefore be unreliable if the sample contains fillers or other additives.

NOTE: Reduced viscosity is also known as the Staudinger function (Jv) and intrinsic viscosity as the Staudinger index (Jg).

This part of ISO 1628 specifies a method for the determination of the viscosity number (also referred to as "reduced viscosity") of dilute solutions of thermoplastic polyesters (TPs) in certain specified solvents. The method is applicable to poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly- (cyclohexylenedimethylene terephthalate) (PCT), and poly(ethylene naphthalate) (PEN), as well as to copolyesters and other polyesters, referred to in ISO 20028-1:2019, that are soluble in one of the specified solvents under the specified conditions.

The viscosity number is determined by the general procedure specified in ISO 1628-1:2024, observing the particular conditions specified in this part of ISO 1628.

The determination of the viscosity number of a thermoplastic polyester provides a measure of the relative molecular mass of the polymer.