What are the different thickening agents:
The following are some of the important thickens used in the textile industry:
1. Starches
2. Gum tragacanth
3. Gum Arabic
4. Sodium alginate
5. Lamitex
6. British gum or dextrins
7. Carboxymethyl cellulose
8. Methylcellulose
9. Emulsion thickener
Table of Contents
1. Starches:
Starch is a polymer of high molecular weight glucose. It is found to be a plant. The starch thickening agents used in textile printing are usually found in wheat, cereals, potatoes, rice, and maize. These products can be used to make thickeners suitable for printing paste. Thickener paste can be made by mixing 0.5 to 1 pound or 8 percent to 12 percent per gallon of water. https://bdfabric.com/wool-fabric-printing-by-reactive-dye/
First, the starch is soaked in cold water. Then the temperature is gradually increased and brought to boiling. The starch starts to swell at a temperature of 70°C. Chemically starch is a carbohydrate. These include Straight Chain, Polymer Amylose, and Branched Chain Polymer (Amylopectin) Both of these types of starch compounds are insoluble in water and alcohol. This starch is highly soluble in hot water. Such soluble starch is widely used in printing paste. Also one of the reasons why starch is widely used in printing paste is that it is cheap and has no reaction with alkali. Either way, it is convenient to use starch.
2. What are the different thickening agents-Gum tragacanth:
This gum is found in a plant called Leguminous, which looks like Astragalusgummifer. Which is marketed in the form of dark yellow to very transparent lumps or leaves. Generally, clean white gum is best. This white gum is easily dissolved in water and pasted. When this paste is boiled, it becomes a smoother paste. This thickening agent is widely used. Sometimes the use of this gum can be noticed even when mixed with starch. This type of thickener is very useful for clothes that are not washed well after printing.
Recipe:
80% Tregakanth is mixed with 1000% water and kept for 2-3 days and occasionally the mixture has to be stirred. The mixture is then boiled until all the gum has dissolved. This is how gum is made.
3. Gum Arabic:
Such gum is collected from the sap of various species of the genus Echachiaarabia. The color of this gum is a pale yellow to dark gray reddish. The one that dissolves easily in water is the best. Gum arabic is slightly acidic and contains 12 to 16 percent moisture. Gum arabic thickener is good for printing by nylon cloth acid dye. It also works well in printing by cotton vat dye. It is also used exclusively in silk fabric printing and can be easily removed from fabrics.
Recipe:
The paste is made by mixing 600% gum arabic in 500% water and then it is prepared in 100% quantity and boiled for 3 hours. It is then cooled and prepared for printing in the ratio of 1000% and sifted.
4. Sodium alginate:
Its origin is from the seaweed Algac. In 1883, an inventor named Stanford made a viscose solution by reacting a dilute solution of sodium carbonate with alginic acid derived from algac. However, not all types of seaweed produce algae. Only two or three classes of algae are found. Besides, this type of algae can be easily collected as it is near the seashore.
5. What are the different thickening agents-Lamitex:
It is sodium alginate produced in the Norwegian region. Soluble in both cold and hot water. However, if not shaken properly, it can be frozen. Viscosity is good. This thickener is very useful for printing by Reactive, Acid, and Disperse dyestuff. It can be used in combination with thickeners (such as starch).
6. British gum or dextrins:
The term British gum is used to refer to a wide range of starch products. Where soluble dextrin is obtained by partially or completely changing starch products in different ways.
In 1810, an Englishman named Bouillon Lagrange discovered that it was easier to thicken starch by mixing it with cold water after frying. Dextrin was then made by frying starch at a temperature of 200°C to 210°C. Dextrin was widely used in 19th century England and India for calico printing or cotton cloth printing. Later, according to the variety of frying, it was marketed as Dark British Gum and Light Fried British Gum.
Dark British gum is made by frying pure starch and turning it into a hard brown color. This dextrin is made by mixing 6 pounds of gum in every gallon of water. In the case of light fried gum, a thickener is made by mixing 3.5 to 4 pounds of gum per gallon of water. However, this viscosity is increased by frying the starch in 1 percent nitric acid instead of frying it directly. In that case, it is possible to reduce the use of the gum. This British gum has the property of being equally soluble in water. In addition, it can be easily washed and removed at the end of the work. This makes the print beautiful and clean with Naphthalene Base and Direct Dye Stuff and also makes the thinner paste last longer.
7. Different thickening agents-Carboxymethyl cellulose:
Commercially, sodium carboxymethyl cellulose is widely available in the form of white fiber powder. Soda cellulose is first obtained by reacting cellulose with a concentrated sodium hydroxide solution. This soda cellulose reacts with sodium chloride acetate to produce sodium carboxy methyl cellulose powder.
Generally, carboxymethyl cellulose contains 0.75% carboxymethyl group per cellulose. It can be easily mixed with cold and hot water to make a transparent thickener. It gives better results than other gums. A good thickener is usually made using 2%. It is very useful for printing by Vat Dyestuff, Soluble Vat Dye Stuff, and Azo Color. It can be easily removed once the dye has settled on the fabric according to the design.
8. Methylcellulose:
This is also a kind of thickener. Cellulose ethers are usually reacted with a solution of concentrated sodium hydroxide and then with alkyl halides to form methylcellulose. It is soluble in cold water but insoluble in hot water. It usually works well in printing by naphthalene base. Combined with starch, it is used in printing like Vat Brother and Direct. Can be easily removed from the fabric at the end of printing.
9. Emulsion thickener:
In addition to conventional thickeners, inert oils such as white spirit, mineral spirit, etc. can be made into emulsion thickeners using a very fast-moving shaker by adding a useful emulsifier product (which helps to mix oil and water). This emulsion thickener is especially useful for high-temperature dyeing methods. Especially pigments disperse and some classes of reactive paints when ripe at high temperature (thermosol). Emulsifiers are very important in the manufacture of emulsion thickeners. As a result, oil and water do not separate.
