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

Studying all possible Fixation Modes of Reactive Printing. Evaluating CMC and Strength Report through Data Color

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Studying all possible Fixation Modes of Reactive Printing. Evaluating CMC and Strength Report through Data Color

Chemicals:

Dye, Stock paste.

Purpose:

Purpose is to propose different fixation modes other than recommended (Steaming) with little or no compromise on yield and tone of shade.

Recipe:

Stock paste:

Mild. Oxidizing agent                  10  g/Kg

Urea                                          100g/Kg

Sodium Bicarbonate                   25  g/Kg

Alginate Thickener                      25 g/Kg

Water                                       Balance

Total                                       1 Kg

Dye Glass:

Dye                                         50  g/Kg

Stock paste                              Balance

Total                                       1 Kg

Options:

Options which are being tried are as follow.

Fixation through Curing/Heating only at strenter (Oven) without Air Flow Control.

Fixation through Curing/Heating only at strenter with Air Flow Control.

Fixation through Steaming by utilizing Saturated Steam.

In addition to these modes different other parameters like time was also varied to see the behavior of the dyes on varying fixation Modes.

Jeans/Denim pents/trousers seem first resistance to Snake bites

Narrated and Coated  "When I was a medical student, I served a summer externship in 1975 with the Indian Health Service at Fort Belknap in Harlem, Montana. On some hot summer evenings, I went fishing at a place the locals called "Snake Lake," which was loaded with cutthroat trout, and surrounded by rocky outcroppings that were home to scores of rattlesnakes. I was advised to stay away from the rocks, and to always wear long pants.

In the December, 2009 issue of the Annals of Emergency Medicine (Ann Emerg Med 2009;54:830-836), there appeared an article reporting a study by Shelton Herbert, PhD and William Hayes, PhD entitled "Denim Clothing Reduces Venom Expenditure by Rattlesnakes Striking Defensively at Model Human Limbs." The purpose of the study was to determine whether ordinary clothing (denim material from blue jeans) interferes with the kinematics of venom delivery, thereby reducing the amount of venom injected by a typical snake into a (model) human limb.

Discharge is like ABC...

Self Explanatory Video

Color Discharge on Reactive Printed/Dyed fabric through Sulfur Dyes.

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Color Discharge on Reactive Printed/Dyed fabric through Sulfur Dyes.

Chemicals:

Urea, Sodium Bicrarbonater, Sulfur Dyes, Reactive Dyes, Rangolit C (Sodium formaldehyde Sulfoxylate HOCH2SO2Na). Sodium perborate, Textile Washing off agent.

Discharge:

Discharge is not a new term for a textile Person. Discharge is classified into white and Color Discharge. Term Discharge may be mixed up or used instead of stripping which is not right as stripping is to lower the depth of shade (usual dyers term) where as during discharge screens are used to create patterns by removing partial or full color of the fabric (Textile Printers term).

Printing is now done on variety of fabrics consequently with variety of dyes. In this post we are just focusing on discharging cotton fabric printed/Dyed with Reactive dyes. Suitable discharging agent for reactive dyes or printed fabric is Rangolit C (Sodium formaldehyde Sulfoxylate HOCH2SO2Na). It is prepared by chemically reacting dilute solution of formaldehyde with Sodium Hydrosulfite. So, like Hydrosulfite it is also strong reducing agents. That why no dye can stand with Rangolit and get reduced consequently ending up by losing their colors. Therefore discharging reactive with reactive is not frequently heard process.

Black Ground Discharged with Yellow Sulfur Dye.

As, discussed Earlier discharge can be of two types White or color Discharge. White is done with rangolic C and later one is majorly carried out with Pigment and Binder system, Such binders are considered which are stable with rangolit C. so Rangolit C (Sodium formaldehyde Sulfoxylate HOCH2SO2Na) discharges ground dyed/Printed Fabric and resultantly pigment take over the white ground produced by rangolit C. The only drawback in this process is that pigment printed fabrics have very poor rubbing and washing fastnesses. So, One has to compromise at this end. So, why not to propose some other method rather than a typical pigment binder color discharge.

Purpose:

Purpose is to propose an other method else than pigment binder for color discharge on reactive Printed/Dyed Fabric.

Sulfur Dye Suitability:

Sulfur dyes are reduced before dyeing or Printing.Normally this is done with reducing agent like Sodium Hydrosulfite Na2S2O4. As, we have discussed earlier  Rangolit C (Sodium formaldehyde Sulfoxylate HOCH2SO2Na) is a reducing agent which can replace Hydro sulfite but, Here need of Rangolit will be much greater as it has to perform two tasks one, Iit has to reduce the dye and secondly it has to discharge the ground color.