Why people choose Thiourea Dioxide to replace Sodium Hydrosulfite in Textile and Paper industry

Thiourea Dioxide

1.Physical and Chemical Properties

Other Name: Formamidine sulfinic acid, Amino imino methanesulfinic acid

Appearance and Odor: White crystal powder, odorless

2. Specification:

Purity: 99.%Min

Thiourea: 0.10%Max

Moisture:0.05%Max

Iron(Fe):10ppm Max

Sulphate: 0.17%Max

3,Why Customers choose Thiourea Dioxide(TDO):

Sodium Hydrosulfite is being used in the textile industry as a reducing agent

for dyeing vat and sulfur vat dyes; as a reducing-washing agent for fabrics

dyed with dispersion dyes; as a decolorizing agent for dyed fabrics; as a

bleaching agent for wool, silk and polyamide fabrics; etc. However, various

handling problems are inherent in its use such as unstable storage life in

powdered form, generation of obnoxious sulfurous acid gas, adsorption of

moisture, generation of heat when in contact with water and possibility of

igniting. Furthermore, since it decomposes very quickly in aqueous solution,

there is an added disadvantage of requiring several times more than its

theoretical amount. Its decomposition in chemical solution during storage for

use in continuous dyeing of vat and sulfur vat dyes is also so great as to

present considerable difficulties in maintaining its concentration.

We take great pleasure, therefore, in introducing to you our TDO, a reducing

agent for overcoming all these difficulties mentioned above with Sodium

Hydrosulfite.

Special Characteristics of TDO

1. Since it is a white powder incapable of any oxidative or reductive action

alone, TDO has a very stable storage life.

2. TDO is not hygroscopic and is absolutely free from deliquescence of

caking.

3. TDO does not generate heat when in contact with water or ignite under

impact.

4. TDO does not emit obnoxious sulfurous gas like Sodium hydrosulfite.

5. Preparation of solution with TDO is simplified since far less amount is

required than with Sodium Hydrosulfite.

6. An aqueous solution of TDO is not only very stable when stored but also

when on fabrics regardless of what the PH is. Hence process and quality

controls in continuous dyeing, bleaching, reducing-washing and

decolorizing operations are easy and dependable.

7. TDO shows very high reduction potential in aqueous solution. Hence

dyes difficult to reduce and decolorize with Sodium Hydrosulfite are

possible with TDO. Furthermore, wool can be bleached to a high level

of brightness with TDO. However, when using TDO as a reducing agent

in dyeing vat dyes, an anti-reducing agent is necessary for preventing

excessive reduction of indanthrone based dyes.

8. In bleaching wool with TDO, uniform dyeing is obtained due to its slow

decomposition in bleaching solution. Moreover, TDO can be used in

continuous steam bleaching with far less shrinkage and damage than

with Sodium Hydrosulfite.

9. It does good to the environment, not increase waste water pollution load,

and conforms to the environmental protection requirements---save

production cost.

If you have any questions or demands, please send email to us: jack.guo@hongyechem.com