J.M. Lucas, R.A.L. Miguel, P.T. Fiadeiro, M.J.S. Silva, M.L.A.G. Carvalho [email protected] University...

J.M. Lucas, R.A.L. Miguel, P.T. Fiadeiro, M.J.S. Silva, M.L.A.G. Carvalho

[email protected]

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 CongressScientific Computation, Applied Mathematics and Simulation

Paris, France July 11 - 15, 2005

J. M. Lucas University of Beira Interior - PORTUGAL


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



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



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



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. I

ntroduction



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



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



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



Materials and Methods 10 fabrics

100% wool10 fabrics

polyester/wool

Gloss formation of fabrics

Woolmark Company IWS TM112 test

method

Behaviour

Recommendations

Useful life Limit

20000 abrasion cycles

Abrasion Stages

1000

5000

10000

15000

20000

100

200

400

600

1000

1500

2000

3000

5000

10000

15000

20000



Materials and Methods

1000

5000

10000

15000

20000

Image Analysis System

All fabrics

100

200

400

600

1000

1500

2000

3000

5000

10000

15000

20000

Laser Setup

2 WO

2 PES/WO

fabrics

Panel of Users:

Wear Limit



Results and Discussion

Recent work

In the most recent works, the Differential Gloss Gradient (DGG) at 20000 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.

0123456789

10

Same appearance as original fabric

Highest amount of gloss




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.




Recent work

Wool Fabrics Polyester/Wool Fabrics

Fabric DGG(20000 cycles)

User´s Panel Evaluation

Fabric DGG(20000 cycles)

User´s Panel Evaluation

LAL1 35 4 PLL1 3,6 3

LAL2 53,8 1 PLL2 37,7 7

LAL3 98,5 7 PLL3 17,4 8

LAL4 70,3 8 PLL4 58,5 10

LAL5 14,4 1 PLL5 8,5 1

LAL6 33,4 5 PLL6 24,2 7

LAL7 4,6 1 PLL7 43,7 7

LAL8 159,6 10 PLL8 13,8 5

LAL9 57,5 5 PLL9 3,5 1

LAL10 29,3 3 PLL10 42,3 8

Regression CoeficienR2 = 73%

Regression CoeficienR2 = 71%

CORRELATION BETWEEN OBJECTIVE AND SUBJECTIVE GLOSS EVALUATION FOR WOOL AND POLYESTER/WOOL FABRICS



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.



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.



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.



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 20000 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.


J.M. Lucas, R.A.L. Miguel, P.T. Fiadeiro, M.J.S. Silva, M.L.A.G. Carvalho

[email protected]

University of Beira Interior

R&D Unit of Textile and Paper Materials – Dep. of Textiles

Covilhã - PORTUGAL



100% wool fabrics

Characteristics of fabrics studied

Fabric Weight

(gr/m2)

Weave Kind of Finish

Colour Effect

LAL1 174 Plain Clear Single colour

LAL2 184 Plain Clear Blend

LAL3 146 Plain Clear Blend

LAL4 174 Plain Clear Single colour

LAL5 203 Twill 3 Soft Milled Blend

LAL6 147 Plain Clear Different colours of warp

and weft

LAL7 181 Twill 3 Soft Milled Blend

LAL8 174 Twill 3 Clear Single colour

LAL9 161 Twill 2/2 Clear Blend

LAL10 225 Fantasy Clear Single colour

Fabric Weight

(gr/m2)

Weave Kind of Finish

Colour Effect

PLL1 243 Twill 3 Clear Single colour

PLL2 188 Fantasy Clear Single colour

PLL3 161 Plain Clear Single colour

PLL4 177 Fantasy Clear Different colours of warp

and weft

PLL5 177 Plain Clear Blend

PLL6 218 Twill 2/2 Clear Single colour


PLL8 196 Fantasy Clear Single colour

PLL9 184 Plain Clear Blend


polyester/ wool fabrics



Differential Gloss Gradient values for each abrasion stage of 100% wool fabrics, using the image analysis

system


Previous work

0,0

20,0

40,0

60,0

80,0

100,0

120,0

140,0

160,0

180,0

1000 5000 10000 15000 20000

Abrasion Stage (cycles)

Dif

fere

nti

al G

los

s G

rad

ien

t (%

)

LAL1 LAL2 LAL3 LAL4 LAL5 LAL6 LAL7 LAL8 LAL9 LAL10



0,0

10,0

20,0

30,0

40,0

50,0

60,0

70,0

1000 5000 10000 15000 20000


Diff

eren

tial G

loss

Gra

dien

t (%

)

PLL1 PLL2 PLL3 PLL4 PLL5 PLL6 PLL7 PLL8 PLL9 PLL10

Differential Gloss Gradient values for each abrasion stage of polyester/wool fabrics, using the image

analysis system


Previous work



Number of limit abrasion cycles for a limit DGG (wool fabrics).

Fabric Image Analysis System

R2 (%) Number of limit cycles

LAL1 91.26 67784

LAL2 91.40 17713

LAL3 98.97 13046

LAL4 99.25 12324

LAL5 94.27 (3)

LAL6 78.74 (1)

LAL7 93.72 78543

LAL8 98.41 8448

LAL9 98.94 15001

LAL10 95.71 26449

Number of limit abrasion cycles for a limit DGG (polyester/wool fabrics).

Fabric Image Analysis System

R2 (%) Number of limit cycles

PLL1 11.84 (1)

PLL2 89.88 20239

PLL3 96.80 (2)

PLL4 97.66 12270

PLL5 98.44 102390

PLL6 60.16 (1)

PLL7 99.82 16713

PLL8 73.70 (1)

PLL9 5.07 (1)

PLL10 99.91 18402

Relationship between differential gloss gradient and number of abrasion cycles

(1) Low correlation values

(2) Light colour fabric

(3) Surface pile fabric


Previous work



Differential Gloss Gradient values for each abrasion stage of 100% wool and polyester/wool fabrics,

using the optical laser set up


Previous work

-50

0

50

100

150

200

250

300

100 200 400 600 1000 1500 2000 3000 5000 10000 15000 20000


Dif

fere

nti

al

Glo

ss

Gra

die

nt

(%)

LAL1 LAL4 LAL8 LAL9

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

Textile DepartmentTextile Department

1717thth IMACS WORLD CONGRESS SCIENTIFIC IMACS WORLD CONGRESS SCIENTIFIC COMPUTATION, APPLIED MATHEMATICS AND COMPUTATION, APPLIED MATHEMATICS AND

SIMULATIONSIMULATION

Paris, France July 11-15, 2005Paris, France July 11-15, 2005

A NEW EQUIPMENT FOR PILLING EVALUATION ON A NEW EQUIPMENT FOR PILLING EVALUATION ON WOOL FABRICS BASED ON OPTICAL ANALYSISWOOL FABRICS BASED ON OPTICAL ANALYSIS

M.L.Carvalho, R.A.L.Miguel, J.M.Lucas, P.T.Fiadeiro, M.J.S. Silva

Pilling formationPilling 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.


Textile DepartmentTextile Department


Textile Department Textile Department

PillingPilling is the formation of fuzzy balls on the surface of a fabric.

PillingPilling occurs when loose fibres in the fabric are worked to the surface after the fabric is subjected to abrasion.

PillingPilling phenomenonphenomenon is highly revealed on fabrics made of synthetics fibres.



Evaluation of fabric ability for pilling formation: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 The accuracy of the results not always is the best onealways is the best one



EVALUATIONEVALUATIONThe 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.



EVALUATIONEVALUATION In this study, we propose a method for pilling evaluation, objective,, 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.



Optical profile analysisOptical profile analysis

The proposed method is based on the shade generated by the pilling developed along the sample optical profile..

Original sample Sample with pilling



Experimental mountingExperimental mounting



It is possible to quantify the variation of the illuminated area L

L = Lp – LaL = Lp – La

Lp- illuminated area of original sample

La- illuminated area of the sample subjected to abrasion

Pilling Index IP:Pilling Index IP:

IP = IP = ( (L / Lp)x100L / Lp)x100



RESULTS AND DISCUSSIONRESULTS 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

1

1-2

2

2-3

3

3-5

4

4-5

5

98.624

97.997

97.951

98.887

99.071

99.048

99.077

99.049

99.326

94.644

94.756

95.049

97.129

97.758

97.657

98.616

98.445

99.300

3.977

3.241

2.902

1.758

1.313

1.391

0.461

0.634

0.026

4.033

3.308

2.963

1.778

1.32 5

1.404

0.465

0.640

0.026



Relationship between the conventional degree of pilling PD and the pilling index IP (average values)

-1

0

1

2

3

4

5

1 1.5 2 2.5 3 3.5 4 4.5 5

Pilling Degree PD

Pill

ing

Inde

x IP

1,5 corresponds to 1-2 degree 2,5 corresponds to 2-3 degree3,5 corresponds to 3-4 degree 4,5 corresponds to 4-5 degree



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 degree3,5 corresponds to 3-4 degree 4,5 corresponds to 4-5 degree



RESULTS AND DISCUSSIONRESULTS AND DISCUSSION

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 PDIP = 4.75 – 0.96 PD

This equation has an interesting correlation coefficient R2 of 89.8%



CONCLUSIONSCONCLUSIONS

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.




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.




The correlation found has an R2 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.

J.M. Lucas, R.A.L. Miguel, P.T. Fiadeiro, M.J.S. Silva, M.L.A.G. Carvalho [email protected] University...

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