Congo Red Direct Scrlet 4BE

Application of Congo Red

Congo Red mainly used for dyeing cellulose fiber fabrics such as cotton and viscose, with good dye uptake, poor transfer ability, and salt sensitivity. Not suitable for direct printing, but can be used for ground color discharge dyeing. It can also be dyed with silk and wool, and can be used in other aspects

In the dyeing of biology and pulp, it can also be used as an acid-base indicator (i.e. Congo red test paper, pH 3-5) and surface coloring of paper.

Packing of Congo Red

Congo Red packing in 25kg lron Drum/Bag, or as per the requirements of customers.

Storage & Transportationy: it must be stored dry & cool warehouse. Avoid to be contacted with oxidizing chemicals and combustible organic substances. Keep it away from direct sunlight, heat, sparks and open flames. Carefully handle the product and avoid damaging the package.

What is Congo Red

Congo Red is red powder. Soluble in water in a yellow red solution, soluble in ethanol in an orange color, slightly soluble in acetone. When exposed to concentrated sulfuric acid, Congo Red turns dark blue, and after dilution, it turns light blue to blue precipitate. Adding concentrated hydrochloric acid to dye aqueous solution to form a red light blue precipitate; Adding acetic acid turns the blue light purple into a relatively red blue precipitate; Concentrated sodium hydroxide turns yellow. Congo Red has poor acid and light fastness, and is highly sensitive to acids and alkalis. For dyeing cellulose fibers, the dye has good absorbance and the maximum affinity at 80C. This product has good discharge properties and is sensitive to hard water. When encountering copper colored light, it is yellow and dark, and when encountering iron colored light, it is slightly yellow.