Effect of Padder Roller Speed and Pressure During Pre-treatment on Color Characteristics of Digitally Printed Cotton Knit Fabric - PowerPoint PPT Presentation

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Effect of Padder Roller Speed and Pressure During Pre-treatment on Color Characteristics of Digitally Printed Cotton Knit Fabric

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No chemical or detergent was added to the wash water. The wash/rinse post-treatment cycles consisted of two cold washes (20-30C or 68 ... – PowerPoint PPT presentation

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Title: Effect of Padder Roller Speed and Pressure During Pre-treatment on Color Characteristics of Digitally Printed Cotton Knit Fabric


1
Effect of Padder Roller Speed and Pressure During
Pre-treatment on Color Characteristics of
Digitally Printed Cotton Knit Fabric
  • Grace Wasike Namwamba, Ph.D.
  • and
  • Devona L. Dixon, M.S.
  • Textile Technology
  • Southern University Agricultural
  • Research and Extension Center
  • Baton Rouge, LA 70813

2
Background
  • Purpose of roller speed (RPM)
  • Importance of roller pressure (PSI)
  • Importance of color

3
Purpose of the Study
  • The purpose of this study was to determine the
    effect of padder roller speed (RPM) and pressure
    (PSI) on the color of digitally printed cotton
    fabrics.
  • The padder for applying pre-treatment and fabric
    preparation is critical to the overall appearance
    of color of the final product. The padder
    parameters, which include roller speed and
    pressure, contribute to the final overall print
    quality/appearance.

4
Procedure
  • Procedure 1-yd of 100 Double knit cotton
    fabric was padded with a pre-treatment fabric
    solution made in lab
  • aliginate (.008),
  • soda ash (.04),
  • urea (.1), and
  • distilled water (.852).
  • A smooth padding pretreatment mixture was poured
    into the padder reservoir for fabric padding
    pre-treatment.

5
Procedure (Continued)
  • Padding Speeds 20, 40, 60 rpm
  • Padding Pressures 5, 15, 40, 60, 70 psi
  • Backing with warm iron and freezer paper
  • Printing Reactive inks on a Mimaki TX2-1600
    Digital Textile Printer
  • Colors Individual one inch stripes of cyan,
    yellow, magenta, black (CYMK) and measurable
    areas of red, pink, violet and green.

6
Procedure Continued
  • Steaming Low pressure bullet steamer for 30
    minutes at 245F the reactive ink dyes were
    fixed to the fabric with steam .
  • Post treatment (Wash/rinse) a commercial
    washing machine used. No chemical or detergent
    was added to the wash water.
  • The wash/rinse post-treatment cycles consisted of
    two cold washes (20-30C or 68-86F) for 6
    minutes and two cold rinse cycles, immediately
    followed by two hot washes (60C or 140 F) for 6
    minutes and two cold rinse cycles. One additional
    cold rinse was added after the final wash/rinse
    cycle.

7
Procedure Continued
  • Color Readings Color readings were taken from
    each of the samples using the Colorguide 45/0
    spectrophotometer.
  • Ten (10) readings were taken from each solid
    color represented in the print in each condition
    (post-print, steamed, post wash/rinse).

8
Statistical Analysis
  • Statistical Analysis Data obtained by
    instrumental color measurement were analyzed
    using SPSS to determine if there was significant
    differences in L, a, b and ?E after the
    treatments. Descriptive statistics were also
    computed.
  • The General Linear Model (GLM) plt.05 The
    statistical model used was as follows
  • Yi,j ?i ?i ej(i)
  • y ij is the value of the dependent variable
    for sample j receiving treatment i,
  • ?i is the overall mean for the dependent
    variable,
  • ?i is the effect of treatment i on the dependent
    variable, and
  • e j(i) is the effect of jth sample receiving
    treatment i.

9
Results and Discussion
  • Effect of Roller Speed on Color Depth
  • The general trend of L was consistent among the
    eight colors.
  • Fabrics padded at 40rpm produced the darkest
    shades (see Chart).
  • Multiple comparisons using LSD indicated that
    there was no significant difference in L values
    for fabrics padded at 20 rpm and those padded at
    60 rpm.
  • Padding at a lower speed of 20 rpm did not
    produce the darkest fabrics as expected.

10
Results and Discussion
  • The explanation of the lightness of fabrics
    padded at 20 rpm lies in the dye chemistry of the
    fiber reactive dyes used to print the fabric.
    Fiber reactive dyes react with cellulose in the
    presence of alkali (NaOH) and electrolyte (NaCl)
    to form cross-linked compounds that are insoluble
    in water. The slow padding speed means greater
    uptake of the padding liquid into the fiber. This
    in turn would result in deeper dye penetration
    into the fiber and less dye on the surface of the
    fabric. Less dye on the surface of the fiber
    results in lighter colors.

11
Results and Discussion
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