What are the ingredients of reactive dye substitute alkali

1. Phosphate system

The representative product of the substitute alkali for the phosphate system is the Alkaflo.Morran patent developed by Sybron Company. The specific method for the substitute alkali of the system is given, and different raw materials can be used to prepare the alkali solution of different pH values. The main components of high pH lye are tripotassium phosphate, potassium hydroxide and sodium hydroxide (the dosage is small, the purpose is to improve the stability of the lye to temperature, you can choose not to add it). The main components of low pH lye are sodium dihydrogen phosphate and phosphoric acid. If the high and low pH lyes are mixed in different proportions, a series of lyes with different pH values can be obtained. Adding borate, ethanolamine, etc. to the lye can improve the buffer capacity of the system, wherein the ethanolamine can be monoethanolamine, diethanolamine, triethanolamine or a mixture thereof.

When preparing lye with high pH value, the dosage of tripotassium phosphate is 20%-50%, potassium hydroxide is 2.5%-20%, if you choose to add sodium hydroxide, the dosage is 0.4%-7%, ethanolamine is 4% ~ 8%, borax pentahydrate is 4% ~ 10%. When preparing low pH lye, sodium dihydrogen phosphate is 13% to 40%, phosphoric acid is 0 to 30%, and ethanolamine is 1.9% to 4%. The patent states that the amount of lye in the dye bath is 0.1% to 0.3%.

The lye of the phosphate system has a good fixation effect in the dyeing of reactive dyes, but its application is limited due to its rich phosphorus.

2. Silicate system:

The substitute alkali under the trade name of BEMOLFB is the product of the silicate system. The main components of the lye prepared in Aseirvatham's patent are: potassium hydroxide, potassium silicate, and chelating agent. The chelating agent is added to remove metal ions and avoid their adverse effects on dyeing. Commonly used chelating agents include sodium salt of ethylenediaminetetramethylenephosphonic acid, sodium salt of ethylenediaminetetraacetic acid, sodium salt of aminotriacetic acid, phosphonate and sodium gluconate. In potassium silicate, the ratio of SiO2 and K2O is variable, and the best mass ratio is: 1.43-2.09 (2.24-3.28 when replaced by quantity). The typical formula is shown in the following table. The dosage is 2～2.5g/L.

The main components of the lye in Christie's patent are: potassium hydroxide, sodium silicate, borate. The best composition is: potassium hydroxide 35%, sodium silicate 25%, borate 5% (such as sodium perborate, sodium metaborate, etc.) water 35%. The prepared lye has both sufficient pH value (to ensure the reaction between dyes and fibers) and sufficient buffer capacity (to make the reaction proceed slowly). The amount of lye in the dye bath is 2-10%. Alkali substitute for silicate system has good color fixing effect, but it will precipitate with metal ions, cause equipment blockage or form spots on fabrics, which can be alleviated by adding chelating agent.

3. Carbonate system

Alternative bases under the trade name Burco NP-QS alt are products of carbonate systems. Its main components are: sodium hydroxide, potassium hydroxide, sodium carbonate, citrate, acrylate, which is a mixed alkali composed of inorganic bases and organic bases.

The main components of the substitute alkali given in the Moore patent: potassium hydroxide, potassium carbonate, potassium citrate, potassium polyacrylate. Among them, citrate and polyacrylate are the crystallization inhibitors of the solution and also act as dispersants in the dyeing process. Potassium carbonate is prepared by adding liquid carbon dioxide to potassium hydroxide solution. Definitions of total alkalinity and effective alkalinity are also given in the patent. Total alkalinity refers to the amount of hydrochloric acid consumed to calibrate to the end point of titration with methyl orange as an indicator, and effective alkalinity refers to the amount of hydrochloric acid consumed to calibrate to the end point of titration with phenolphthalein as an indicator. The following table is the total alkalinity, effective alkalinity and pH value of 2% solution of sodium carbonate, Alkaflo, Burco NP-Q solution measured in the patent.