Gummi- och plastindustri

Ämnesområden: Plast: allmänt
Kommittébeteckning: SIS/TK 156 (Plast)
Källa: CEN
Svarsdatum: den 7 jul 2018
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This document specifies a method for determining the ultimate aerobic biodegradability of plastic materials in soil by measuring the oxygen demand in a closed respirometer or the amount of carbon dioxide evolved. The method is designed to yield an optimum degree of biodegradation by adjusting the humidity of the test soil.

If a non-adapted soil is used as an inoculum, the test simulates the biodegradation processes which take place in a natural environment; if a pre-exposed soil is used, the method can be used to investigate the potential biodegradability of a test material.

This method applies to the following materials:

— natural and/or synthetic polymers, copolymers or mixtures of these;

— plastic materials which contain additives such as plasticizers or colorants;

— watersoluble polymers.

It does not necessarily apply to materials which, under the test conditions, inhibit the activity of the microorganisms present in the soil. Inhibitory effects can be measured using an inhibition control or by another suitable method. If the test material inhibits the microorganisms in the soil, a lower test material concentration, another type of soil or a pre-exposed soil can be used.

Ämnesområden: Plast: allmänt
Kommittébeteckning: SIS/TK 156 (Plast)
Källa: CEN
Svarsdatum: den 7 jul 2018
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1.1 This document specifies methods for the determination of the water content of plastics in the form of powder, granules, and finished articles. These methods do not test for water absorption (kinetics and equilibrium) of plastics as measured by ISO 62.

Method A is suitable for the determination of water content as low as 0,1 % with an accuracy of 0,1 %.

Method B and Method C are suitable for the determination of water content as low as 0,01 % with an accuracy of 0,01 %. Method D is suitable for the determination of water content as low as 0,01% with an accuracy of 0,01%. Method E is suitable for the determination of water content as low as 0,001% with an accuracy of 0,001%. The stated accuracies are detection limits which depend also on the maximal possible sample weight. Percentage means percentage of water content.

Method D is suitable for polyamide (PA), polycarbonate (PC), polypropylene (PP), polyethylene (PE), epoxy resin, polyethylene terephthalate (PET), polyester, polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polyactide (PLA), polyamidimid (PAI), it is especially not recommended for samples which may release NH3. Method E is generally suitable for every type of plastic and moisture level.

Water content is an important parameter for processing materials and has to remain below the level specified in the appropriate material standard.

1.2 Six alternative methods are specified in this document.

Method A is an extraction method using anhydrous methanol followed by a Karl Fischer titration of the extracted water. It can be used for all plastics and is applicable to granules smaller than 4 mm × 4 mm × 3 mm. The method can also be used for, e.g. prepolymer materials in the form of a powder that are insoluble in methanol.

Method B1 is a vaporization method using a tube oven. The water contained in the test portion is vaporized and carried to the titration cell by a dry air or nitrogen carrier gas, followed by a Karl

Fischer titration of the collected water. It can be used for all plastics and is applicable to granules smaller than 4 mm × 4 mm × 3 mm.

Method B2 is a vaporization method using a heated sample vial. The water contained in the test portion is vaporized and carried to the titration cell by a dry air or nitrogen carrier gas, followed by a Karl Fischer titration of the collected water. It can be used for all plastics and is applicable to granules smaller than 4 mm × 4 mm × 3 mm.

Method C is a manometric method. The water content is determined from the increase in pressure, which results when the water is evaporated under a vacuum. This method is not applicable to plastic samples containing volatile compounds, other than water, in amounts contributing significantly to the vapour pressure at room temperature. Checks for the presence of large amounts of volatile compounds are to be carried out periodically, for example by gas chromatography. Such checks are particularly required for new types or grades of material.

Method D is a thermocoulometric method using a diphosphorus pentoxide (P2O5) cell for the detection of the vaporized water. The water contained in the test portion is vaporized and carried to the sensor cell by a dry air or nitrogen carrier gas, followed by a coulometric determination of the collected water. This method is not applicable to plastic samples containing volatile compounds, other than water, in amounts contributing significantly to the vapour pressure at room temperature. This is specially related to volatile components which may react with the acidic coating of the diphosphorus pentoxide sensor, e.g. ammonia or any kind of amines. Checks for the presence of large amounts of volatile compounds are to be carried out periodically. Such checks are particularly required for new types or grades of material.

Method E is a calcium hydride based method. The water content of a sample evaporates due to a combination of vacuum and heating. The evaporated water reacts with calcium hydride to molecular hydrogen and calcium hydroxide. The hydrogen causes an increase of pressure in the vacuum that is proportional to the evaporated water. Volatile adhesives, that do not react with calcium hydride condensate in a cooling trap and will not affect the measurement.

Ämnesområden: Plast: allmänt
Kommittébeteckning: SIS/TK 156 (Plast)
Källa: ISO
Svarsdatum: den 9 jul 2018
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This document specifies a method of determining the spectral response of ultraviolet and visible radiation for all kinds of plastic material, by spectrally dispersed irradiation.

NOTE Typical specimens that are evaluated include; films, liquids, plaques, pellets, powders, sheets and discs.

Ämnesområden: Gummi
Kommittébeteckning: SIS/TK 154 (Gummi och gummiprodukter)
Källa: ISO
Svarsdatum: den 12 jul 2018
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This document specifies two methods for the determination of the compression set characteristics of vulcanized and thermoplastic rubbers at low temperatures.

Method 1 derives from the methodology used in ISO 815-1. Method 2 uses a specified testing device, allowing to measure and record the test piece thickness during recovery. Due to the load applied during recovery in method 2, no correlation can be established between the results given by both methods.

NOTE When rubber is held under compression, physical or chemical changes that prevent the rubber returning to its original dimensions after release of the deforming force can occur. The result is a set, where the magnitude of which depends on the time and temperature of compression as well as on the time, temperature, and conditions of recovery. At low temperatures, changes resulting from the effects of glass hardening or crystallization become predominant and, since these effects are reversed by raising the temperature, it is necessary for all measurements to be undertaken at the test temperature.