Title: Fibre Labelling - Polypropylene/polyamide bicomponent - Aquafil
Publisher: Publications Office of the European Union
Publication Year: 2010
JRC N°: JRC61247
ISBN: 978-92-79-17456-8
ISSN: 1018-5593
Other Identifiers: EUR 24574 EN
URI: http://publications.jrc.ec.europa.eu/repository/handle/JRC61247
DOI: 10.2788/36853
Type: EUR - Scientific and Technical Research Reports
Abstract: In August 2007, the European Commission¿s Joint Research Centre (JRC) was entrusted by DG Enterprise to verify the validity and applicability of the testing methods, proposed by Aquafil S.p.A., for the identification and quantification of their new fibre (PAC). Experimental results confirmed that identification of PAC can be achieved using Scanning Electronic Microscope (SEM) analysis, after dissolving the polyamide fibrils with formic acid. Additionally, Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC) can be used as techniques to differentiate PAC from binary mixtures made of polypropylene (PP) and polyamide (PA) fibres. For quantification purposes, the normal pre-treatment described in Dir. 96/73/EC, was proved to be applicable to PAC and its correction factor b for mass loss during pre-treatment was established (0 %). The agreed allowance of the new fibre was measured (0.40 %) and the established value, adopted by the European network of national experts on Textile Labelling (ENNETL), was 1.00 %. The solubility properties of PAC, PA6 and PP were evaluated with methods listed in Dir. 96/73/EC. The new fibre was insoluble in methods 1, 2, 5-11 and 14. The d correction factors were established on the basis of the experimental work carried out by the JRC and, in the case of methods 2, 8 and 11, confirmed through a collaborative trial at European level. The resulting values were: 1.00 for methods 1, 2, 5, 6, 8-10, 1.005 for method 11 and 1.01 for methods 7 and 14. PP was insoluble in methods 1, 3, 5-11, 14 and 16; the average d factor values were 1.00 in all cases. PA6 was insoluble in methods 5 and 10 and the average d factor values were 1.00 and 1.01, respectively. Experts agreed that only the correction factors d for PAC and PP shall be inserted in Dir. 96/73/EC, as the ones for PA were measured only on PA6. PA in PAC was quantified via elemental analysis, on the basis of the nitrogen content of PAC samples, to obtain results that could be considered as reference values. Among the tested methods (hydrolysis, DSC, FTIR and chemical dissolution ones), method 16 of Dir. 96/73/EC was proved to be the most accurate and non time-consuming. It was, therefore, proposed by the JRC and agreed by experts as the suitable method to quantify PA in PAC. For the quantification of PAC in binary mixtures, manual separation is an adequate technique, whenever applicable. Several alternative methods were studied for mixtures with PP or PA and their accuracy evaluated by comparison of quantitative results to the reference values obtained via manual separation. Method 16 of Dir. 96/73/EC was proved to be accurate for the quantification of binary mixtures PP/PAC; however, this quantification can only be achieved if the PA content of PAC is known. Method 11 of Dir. 96/73/EC was considered very accurate for the quantification of binary mixtures PA/PAC and was proposed by the JRC. As agreed during the 10th ENNETL meeting, a collaborative trial was organised by the JRC to validate method 11, in accordance with the rules laid down in ISO 5725 (1994). On the basis of successful results, experts agreed that the field of application of method 11 in Dir. 96/73/EC shall be extended to the quantification of binary mixtures PA/PAC. Moreover, the modified washing procedure, needed to achieve a correct quantification of binary mixtures with high percentages of PA fibres, shall be added in the method¿s description together with the established precision of the analytical method, expressed as reproducibility limit (2 %). Based on experimental results, discussions during the 9th, 10th and 11th ENNETL meetings and written consultation with national experts, the name and definition agreed for the new fibre were ¿polypropylene/polyamide bicomponent: a bicomponent fibre composed of between 10 % and 25 % by mass of polyamide fibrils embedded in polypropylene matrix¿.
JRC Directorate:Institute for Health and Consumer Protection Historical Collection

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