Establishment of quantification methods for novel polypropylene/polyamide 6-based bicomponent fibre in textile binary mixtures

Abstract

The aim of this study was the establishment of quantification methods for binary mixtures containing a novel polypropylene/polyamide 6-based bicomponent fibre, for which a new generic fibre name has been requested to the European Commission. Application of such methods is requested by EU legislation to enable market surveillance of the compulsorycomposition labelling of textile products. Evaluating the key parameters for quantification, results showed that the b coefficient for the novel fibre (mass loss due to normal pre-treatment) is equal to 0%. In agreement with the members of the European Network of National Experts on Textile Labelling, the value of 1.00% was established as its agreed allowance (moisture regain in standard atmosphere), on the basis of the experimental value of 0.54%. Among the dissolution methods described in Directive 96/73/EC, the new fibre was insoluble in ten, for which the d correction factors (mass loss of the insoluble component) were evaluated. Three of them were additionally validated through an EU collaborative trial according to ISO 5725:1994. The ten established d correction factors were in the range of 1.00–1.01, revealing complete insolubility or up to 1% solubility of the novel fibre in the dissolution reagents. Based on this study, laboratories now have at their disposal methods to quantify the new fibre in binary mixtures with polyester, elastomultiester, polyamide, chlorofibres, certain acrylic and modacrylic fibres, acetate, triacetate, polylactide, certain cellulose fibres and certain protein fibres.

Method validation by collaborative trial for the quantification of binary mixtures containing polyamide and a novel polypropylene/polyamide bicomponent fibre

“…Data regarding level 4 refer to yarn samples made of 100% novel fibre. They were obtained in a previous collaborative study 3 for the validation of the d correction factor for this modified version of method 11, here expressed as per cent content of novel fibre. All data were investigated for outliers according to ISO 5725-2.…”

“…All results presented so far were calculated on the basis of a d correction factor value for the novel fibre, which was equal to 1.005, 3 as determined through the collaborative trial conducted at European level for this modified version of method 11. Due to the fact that d correction factors are usually established in Directive 96/73/EC with two decimals, the influence of the d factor on trueness was evaluated by calculating the bias for d factor values equal to 1.00, 1.005 and 1.01 (Table 5).…”

“…The solubility behaviour of the novel fibre and PA6, under the conditions of these methods, has already been studied by the European Commission's Joint Research Centre (JRC). 3 Results have shown that the new bicomponent fibre is insoluble under the conditions of method 11 of Directive 96/73/EC, whereas PA6 is completely soluble. This difference in solubility behaviour was the basis for further investigation to check the applicability of this method to the quantification of binary blends made from the novel fibre and polyamide.…”