Unlike starch, Dextrins are soluble in water. The severity of the heat and acid treatment determines the degree of solubility, which is the basis for classifying or grading Dextrins . Finished Dextrins are very fine, powder varying in colour from pure white to light yellow.
Dextrine are prepared by roasting starch in the presence of acid, which chemically changes the character and properties of starch. They are intermediate between starch and sugars derived from starch. They are starch converted products, which find applications in dyes, adhesives, foundries and other industries.
Applications :Adhesive Industry
- High Strength Films
- Excellent Adhesive Properties
- Wide Range of Water Solubilities 20
The adhesive industry uses large amounts of yellow Dextrin in the preparation of liquid and dry adhesives.Dextrins go into solution instantly and with a lesser quantity of water. Because of their greater adhesive strength and fluidity, dextrins are widely used in the manufacture of :-
Chemical & Dyes industry
- Spiral and convolute tubes.
- Carbon paper manufacturing, abrasives and in dry distemper.
- Machine labeling of tins, cartons, packages, envelopes, corrugated boxes etc.
- Also used by crackers manufacturer due to its adhesive properties & also explosive character.
- In Paper tubes and Paper cones.
- In book-binding, carton sealing, pasting, match-head & match box making.
- As a core binder in refractories and foundry operations.
The advantages of Dextrins in the dyestuff industry are so well recognized that good many large-scale manufacturers have taken to using highly soluble Dextrins as diluent to standardize the dyes with respect to the range of colors. Dextrin’s wash out quickly and easily and do not react with chemicals used in the process.Foundries
Yellow Dextrins serves as an excellent binding agent for sand cores in foundry operations. It gives high green bond strength necessary for the mould to remain intact during handling.Textile industry
As Dextrins do not easily react with chemicals, they are specifically suitable for applications in the textile field. In textile printing, they are used as thickness. Free of grit and other impurities, which usually accompany lower grades of starch, they ensure that the copper rolls (used in printing) do not suffer from abrasion. In sizing, they are used with starch for increased adhesiveness. In finishing, they give desired ‘feel’ and handle to the fabrics.Colour Industry
Dextrins are largely used in dry distemper. Two to three percent of dextrins , mixed with chalk and pigment, acts as a carrier and imparts good adhesion of the colour to the wall.