J.M. Lucas, R.A.L. Miguel, P.T. Fiadeiro, M.J.S. Silva, M.L.A.G. Carvalho University of Beira Interior R&D Unit of Textile and Paper Materials – Dep. of Textiles Covilhã - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments 17th IMACS World Congress Scientific Computation, Applied Mathematics and Simulation Paris, France July , 2005

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments The abrasion resistance is one of the most important properties of garment fabrics. During wear, clothes are permanently subjected to friction, either between them or against common objects. Abrasion usually causes: Introduction loss of weight yarn breakage change of colour pilling formation gloss

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Introduction One of the main reasons to reject a worsted fabric is due to the level of gloss caused by wear, this being possible without having a significant weight loss. Rejection point of a garment: Excessive surface gloss Small physical fibre degradation

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Given the multiplicity of parameters that influence the abrasion procedure and the difficulty to quantify the fabric abrasion resistance, no analytic method is yet available which is accepted without constrains by the different textile organisations. The classical methods to evaluate abrasion resistance do not include the assessment of gloss. Introduction

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Testing methods based on the Martindale Wear & Abrasion Tester simulate abrasion undergone by fabrics during wear, the test being carried out up to the breakage of two yarns in the specimens subjected to friction. This is an objective method that does not translate the useful life of fabrics, since well before the physical degradation takes place, fabrics may already have lost wear properties due to the change of their surface appearance. Introduction

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments The testing methodology simulates the abrasion of fabrics against frequent contact materials which enable gloss formation. The Martindale abrasion procedure was changed, the standard abrasion fabric being substituted by a common material that easily allows an increase of gloss. All fabrics tested were subjected to a given set of abrasion stages. Introduction

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Optimistic results have been achieved using three different techniques: Measurement of colour parameters using spectrophotometer, the evaluation of gloss being made using luminance and total colour difference; Assessment of lightness of abraded samples using an image analysis system; Measurement of gloss using an optical set up using a collimated laser beam. Introduction

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Establishment of a gloss measuring quality control method to evaluate loss of appearance of fabrics subjected to abrasion. Establishment of a scientific and technological basis to develop an apparatus for the evaluation of gloss on worn garments. Introduction Objectives

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Materials and Methods 10 fabrics 100% wool 10 fabrics polyester/wool Gloss formation of fabrics Woolmark Company IWS TM112 test method Behaviour Recommendations Useful life Limit abrasion cycles Abrasion Stages

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Materials and Methods Image Analysis System All fabrics Laser Setup 2 WO 2 PES/WO fabrics Panel of Users: Wear Limit

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Results and Discussion Recent work In the most recent works, the Differential Gloss Gradient (DGG) at cycles was evaluated for each fabric. On the basis of a 0 to 10 scale, the user’s panel classified fabrics concerning the amount of gloss formed Same appearance as original fabric Highest amount of gloss

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Results and Discussion Recent work The correlation between the objective evaluation (image analysis system) and the subjective one (user’s panel) has regression coefficient R2 of 73%. From this value it may be considered quite promising to consider a valid objective method, considering the experience of the user’s panel.

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Results and Discussion Recent work Wool FabricsPolyester/Wool Fabrics FabricDGG (20000 cycles) User´s Panel Evaluation FabricDGG (20000 cycles) User´s Panel Evaluation LAL1354PLL13,63 LAL253,81PLL237,77 LAL398,57PLL317,48 LAL470,38PLL458,510 LAL514,41PLL58,51 LAL633,45PLL624,27 LAL74,61PLL743,77 LAL8159,610PLL813,85 LAL957,55PLL93,51 LAL1029,33PLL1042,38 Regression Coeficien R 2 = 73% Regression Coeficien R 2 = 71% CORRELATION BETWEEN OBJECTIVE AND SUBJECTIVE GLOSS EVALUATION FOR WOOL AND POLYESTER/WOOL FABRICS

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Conclusions The low correlation values (1) have been achieved for fabrics which present at least one of the following characteristics: - Polyester fibres in its composition; - Blend effects with a marked contrast; - Yarn unevenness when warp and weft have different colours. For fabrics having these characteristics, the followed method is not the most suitable to evaluate gloss formation.

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Conclusions Comparing the obtained results by both methods to evaluate the gloss formation in fabrics, it can be said that the R2 values for regressions between DGG and the abrasion stages are of the same order for 100% wool fabrics. In polyester/wool fabrics the R2 values between the abrasion stages and DGG obtained using the optical laser set up seem to be much better than those used the other measuring technique.

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Conclusions Based on the experience, the user’s panel may define, as a function of the fabric end use, a limit value on the subjective scale. This value represents the point from which the fabric is no longer suitable for use, due to the high amount of gloss. Through the regression curve, the limit DGG can be found.

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Conclusions Thus, conditions are met to establish a new objective method of quality control concerning the tendency of fabrics to form gloss and, thus, to evaluate the useful life respecting to this characteristic. For this, it is enough to submit the fabric to the abrasion process in the Martindale apparatus, using a proper abrasion surface during cycles. After, the amount of gloss should be measured in both fabric samples, before and after abrasion using the image analysis system, and then calculate the DGG of fabric and compare it with limit DGG defined by the user’s panel.

Innovative Optical Device for Gloss Evaluation of Worn Garments J.M. Lucas, R.A.L. Miguel, P.T. Fiadeiro, M.J.S. Silva, M.L.A.G. Carvalho University of Beira Interior R&D Unit of Textile and Paper Materials – Dep. of Textiles Covilhã - PORTUGAL

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments 100% wool fabrics Characteristics of fabrics studied FabricWeight (gr/m 2 ) WeaveKind of Finish Colour Effect LAL1174PlainClearSingle colour LAL2184PlainClearBlend LAL3146PlainClearBlend LAL4174PlainClearSingle colour LAL5203Twill 3Soft MilledBlend LAL6147PlainClearDifferent colours of warp and weft LAL7181Twill 3Soft MilledBlend LAL8174Twill 3ClearSingle colour LAL9161Twill 2/2ClearBlend LAL10225FantasyClearSingle colour FabricWeight (gr/m 2 ) WeaveKind of Finish Colour Effect PLL1243Twill 3ClearSingle colour PLL2188FantasyClearSingle colour PLL3161PlainClearSingle colour PLL4177FantasyClearDifferent colours of warp and weft PLL5177PlainClearBlend PLL6218Twill 2/2ClearSingle colour PLL7176PlainClearSingle colour PLL8196FantasyClearSingle colour PLL9184PlainClearBlend PLL10224PlainClearSingle colour polyester/ wool fabrics

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Differential Gloss Gradient values for each abrasion stage of 100% wool fabrics, using the image analysis system Results and Discussion Previous work

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Differential Gloss Gradient values for each abrasion stage of polyester/wool fabrics, using the image analysis system Results and Discussion Previous work

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Number of limit abrasion cycles for a limit DGG (wool fabrics). FabricImage Analysis System R 2 (%)Number of limit cycles LAL LAL LAL LAL LAL594.27(3) LAL678.74(1) LAL LAL LAL LAL Number of limit abrasion cycles for a limit DGG (polyester/wool fabrics). FabricImage Analysis System R 2 (%)Number of limit cycles PLL111.84(1) PLL PLL396.80(2) PLL PLL PLL660.16(1) PLL PLL873.70(1) PLL95.07(1) PLL Relationship between differential gloss gradient and number of abrasion cycles (1) Low correlation values (2) Light colour fabric (3) Surface pile fabric Results and Discussion Previous work

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments Differential Gloss Gradient values for each abrasion stage of 100% wool and polyester/wool fabrics, using the optical laser set up Results and Discussion Previous work

J. M. Lucas University of Beira Interior - PORTUGAL Innovative Optical Device for Gloss Evaluation of Worn Garments

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department 17 th IMACS WORLD CONGRESS SCIENTIFIC COMPUTATION, APPLIED MATHEMATICS AND SIMULATION Paris, France July 11-15, 2005 A NEW EQUIPMENT FOR PILLING EVALUATION ON WOOL FABRICS BASED ON OPTICAL ANALYSIS M.L.Carvalho, R.A.L.Miguel, J.M.Lucas, P.T.Fiadeiro, M.J.S. Silva

Pilling formation  Is the result of abrasion fabric that mostly affects its surface appearance.  Is the consequence of abrasion of garments, either between them, or against common objects of day life. UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department

Pilling Pilling is the formation of fuzzy balls on the surface of a fabric. Pilling Pilling occurs when loose fibres in the fabric are worked to the surface after the fabric is subjected to abrasion. Pillingphenomenon Pilling phenomenon is highly revealed on fabrics made of synthetics fibres.

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department Evaluation of fabric ability for pilling formation:  Comparison of fabric appearance with photographic standards;  Counting or weighting the neps on a given surface area of the fabric;  Image analysis techniques;  Laser triangulation techniques. The accuracy of the results not always is the best one

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department EVALUATION  The comparison of the abraded fabric appearance with photographic standards is the most current evaluation method for pilling formation, but this method is highly subjective, and the photographic standard cannot represent all the kind of fabrics.  For this reason, it becomes important the definition of an objective method to evaluate pilling formation.

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department EVALUATION, objective,  In this study, we propose a method for pilling evaluation, objective, based on the optical profile analysis, using a collimated light beam. The optical profiles are measured using a CCD detector along fabric sample, the untreated one and those subjected to pilling.  The pilling simulation was made using Martindale Wear & Abrasion Tester, according to Woolmark TM 196 (2000) Test method.

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department Optical profile analysis. The proposed method is based on the shade generated by the pilling developed along the sample optical profile. Original sampleSample with pilling

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department Experimental mounting

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department It is possible to quantify the variation of the illuminated area  L  L = Lp – La Lp- illuminated area of original sample La- illuminated area of the sample subjected to abrasion Pilling Index IP: IP = (  L / Lp)x100

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department RESULTS AND DISCUSSION The variation of the illuminates area  L increases with the amount of pilling formed. Pilling Degree PD Standard illuminated area Lp Sample illuminated area after abrasion La Difference of illuminated area  L Pilling Index IP

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department Relationship between the conventional degree of pilling PD and the pilling index IP (average values) 1,5 corresponds to 1-2 degree 2,5 corresponds to 2-3 degree 3,5 corresponds to 3-4 degree 4,5 corresponds to 4-5 degree

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department Relationship between the conventional degree of pilling DP and the pilling index IP (measured values) 1,5 corresponds to 1-2 degree 2,5 corresponds to 2-3 degree 3,5 corresponds to 3-4 degree 4,5 corresponds to 4-5 degree

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department RESULTS AND DISCUSSION IP = 4.75 – 0.96 PD The correlation between objective evaluation of pilling formation, given by IP (Pilling Index) and the subjective evaluation of the same property based on photographic scale of standard PD (Pilling Degree) is given by the following mathematics equation: IP = 4.75 – 0.96 PD This equation has an interesting correlation coefficient R 2 of 89.8%

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department CONCLUSIONS The existing methods to evaluate pilling formation are visual and thus subjective. The proposed method allows an objective evaluation of this characteristic. It is based on the relationship between the illuminated area of the optical profiles of fabric with pilling and of original sample (standard). The variation of illuminated area relates directly to the pilling index IP.

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department CONCLUSIONS The next steps will comprise the definition of an equation that better correlates the pilling index IP and the degree of pilling determined by the subjective evaluation. Using a properly designed computer application, the optical system for pilling formation evaluation may convert the optical reading to pilling degree well known in the textile area.

UNIVERSITY OF BEIRA INTERIOR R&D Unit of Textile and Paper Materials – Textile Department CONCLUSIONS The correlation found has an R 2 of 89.9%, this value being quite hopeful to keep increasing the number of tests, in order to achieve a more accurate tendency of the relationship between objective and subjective evaluations.