breed
The main variety of sulphur dyes is sulphur black (C.I. sulphur black 1). It is prepared by hydrolyzing 2, 4-dinitrochlorobenzene and sodium hydroxide solution into sodium dinitrophenol solution at near boiling, then heating and boiling with sodium polysulfide solution at a certain molecular ratio, and reducing and sulfurizing reaction under pressure or no pressure. After the sulfurization reaction is completed, it is dried directly with a roller dryer to obtain the original dye. It is then blended into commercial dyes. During vulcanization, the molecular ratio of sodium phenol and sodium polysulfide, the x(i.e., sulfur index) in sodium polysulfide Na2Sx and the reaction temperature are different, so that the color light of the sulphur black product has the difference of green light, green red light and red light. The biggest disadvantage of sulphur black dye is the phenomenon of brittle cloth. This is because the sulfide black molecule contains active sulfur in the form of polysulfide chains. This composition of sulfur is unstable, and when the dye is heated or placed in hot and humid air, it is easy to oxidize to sulfuric acid, resulting in brittleness of the cotton cloth. In recent years, by improving the production process of sulphur black, the ordinary sulphur black is cooled to about 100℃ after being made, and formaldehyde and monochloroacetic acid are added to stabilize the unstable sulfur in the dye, and an anti-brittle sulphur black dyeing is made.
Use
Sulfur dyes are used to be reduced to water-soluble leucosome with sodium sulfide or insurance powder, and then changed back to the original insoluble colored matter after being absorbed by the dye through oxidation or other effects, so that the dye is fixed on the dye.
Apply
sulphur dyes are widely used in the dyeing of cellulose fibers, mainly used in yarns, shapes and other industrial fabrics and heavy fabrics. The most commonly used varieties are sulphur Yuan, sulphur blue,
Reductive solution
(1) Properties of reducing agents
1. Properties of Na2S
(1) Also known as alkali sulfide, the common name smelly alkali, the effective composition of industrial alkali sulfide is generally about 50%, and the appearance is yellowish-brown solid. It is a reducing agent, but also a strong alkali agent, stable properties. The reducing capacity of sodium sulfide is lower than that of insurance powder, the alkalinity is lower than caustic soda and greater than soda ash, and it has strong corrosion to the skin.
(2) Sodium sulfide hydrolysis to NaHS, NaHS on the dye reduction, it can be seen that sodium sulfide reduction capacity is related to its hydrolysis.
(3) Sodium sulfide produces H2S gas when it meets acid, so care should be taken to prevent it from being put together with acid.
(4) Sodium sulfide exposure in the air will absorb water, C02, 02, etc., so that the effective composition decreases and gradually fails. Therefore, it should be sealed when stored, and its composition should be analyzed when it is not reused for a long time.
(5) Sodium sulfide solution should not be long, otherwise it will be oxidized by air and reduce its effectiveness.
use
Mainly used for cotton, hemp fiber dyeing
Our company mainly produces Sulphur Black Bluish ,Sulphur Blue Brn 150% ,Sulphur Red 14 ,Sulphur Red Dyes and other most sulphur dyes, which are sold at home and abroad, such as Bangladesh, Pakistan, Turkey, India, Vietnam, Italy, etc. It has been recognized and praised by the majority of customers, because of our good quality supervision and low price advantages. We also thank our customers for their support and recognition of our company.
Post time: Mar-05-2024