Pigment Printing

SUBJ-19:

Pigment Printing

Pigment Printing:

For me design/Pattern is printing for others combination of thickener (Paste) and Screen (Design) is called printing. Dyeing can hold single color where as printing can handle 12 to 20 colors in single go. Printing can simply be classified according to Technique, Fiber type and Dye Class.

Note: On graph Bigger the pie {portion of circle} bigger the percentage of that part have. For example Rotary screen on first have more than 50% portion of the circle meaning internationally more than 50% printing is done through rotary printing.

As, Chart Describes major portion of textile printing is covered by Pigment Printing so it becomes an important topic to discuss.To print on different substrates different chemistry is required for example printing on natural cellulose is majorly done with reactive dyes. Polyester is printed with disperse dyes, Cotton is printed with sulfur dyes, but, Pigment printing can be applied to various type of fibers like Cotton, Polyester, Blend PC, Polyamide and many more. Isnt that great enough that one learns a technique of printing and now can apply on every type of substrate. This is really big advantage in the court of pigment printing that makes it more ecological, eco-friendly, efficient and safe.

Pigment Printed on 100% Cotton, Unmercerized

Pigment printing can be taken as wall painting, literally wall painting{Distemper}. If we look at the major constituents involved in wall paint are Binder, COLOR{Pigment}, Thickener, Drying Oil, Drying Agent, Fillers etc. Ok, Lets now see the composition of pigment printing paste its Binder, COLOR{Pigment},  Urea {for controlling formaldehyde}, Thickener, Ammonia{for adjustment of pH}. So, Closely looking the constituents will evaluate that around 65 to 80% components are same in pigment printing and Wall painting Distemper. In simple same constituents same chemistry that wholly relays on the working of Binder and of course we will love it to discuss with you.

Pigment Printed

Understanding Binder:

Nor Pigment printing neither Wall painting is possible without Binder. Binders plays key role in both former and later fields. Binder are mononers which on heating get converted into polymers. Yes I said by simple heating, no pressure , no steaming , no electricity.

Binders{Monomer}------Heat----------> Plasticizer/Plastic{Polymer}

Yeah, binders form plastic but, its too soft and transparent that its difficult to see it but we can feel its harshness on the fabric. That’s why pigment printed fabric have more harshness when compared to other printing techniques. Binder actually hold the pigment color and sandwich it between fabric surface and plastic coating and this coating help color to stick there and stand with high and severe conditions.

In addition to binder an other component is also added to the textile pigment printing paste and that is called fixer. Fixers are mostly formaldehyde based. Have you ever heard word UREA-FORMALDEHYDE,  haana? Actually this is a plastic and used to make plastic plates and dishes with two component Urea {NH2}2CO and Formaldehyde {HCHO} as name suggests. So, Here in our paste formaldehyde work in same manner and form plastic which helps in strengthening of binder to hold on pigment

Hope these figures are self explanatory on the working of Binder that how binder sandwiches pigment in between itself and substrate. As, nearly 90 to 95% of Pigment is successfully entrapped in between so no need of washing as it was required in case of Reactive printing to wash off unfixed dye. This is big advantage of pigment over other techniques which make it economical.

Some Qualities of Binder:

• Good fastness to light, rubbing, washing and Dry cleaning.
• High Brilliancy
• Soft Handle
• Good Thermal Stability
• Simple Application
• Good Shear Stability
• Compatible with other components of Paste.
• Don’t Block print Screen.

Typical Recipe for Pigment Printing:

Soft Water                          700 g/Kg

Anti Foamer                              1g/Kg

Binder                                 200g/Kg

Fixative                                   10g/Kg

Softner                                   10g/Kg

Urea                                        50g/Kg

Thickener                              15g/Kg

Total                                        1 Kg

Note:

Component in Bold are essential and un bold can be skipped out.

A typical Shade Card Preview Containing Fastness record and Shade Depth

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