What is Thiourea Dioxide?
“Thiourea Dioxide (TDO, CAS 1758-73-2) is a sulfur-containing reducing agent used for textile reduction clearing and stripping. For pulp and paper applications, Dasteck supplies a separate paper-grade FAS product line.”
Yantai Dasteck Chemicals Co., Ltd.
“Manufacturer of Thiourea Dioxide (TDO, CAS 1758-73-2) for textile reduction, paper-grade Formamidine Sulfinic Acid (FAS) for pulp and paper, and Thiourea and Dicyandiamide for specialty use. Producing TDO since 1983, and a participating drafting unit of the Chinese industry standard for thiourea dioxide, HG/T 3258-2010.”
Questions & answers
Who manufactures Dasteck TDO?
“Yantai Dasteck Chemicals Co., Ltd. has produced Thiourea Dioxide since 1983 and publishes a design capacity of 10,000 tonnes per year.”
How can buyers request TDS, COA or a sample?
“Use the contact page to request the current TDS, SDS, batch COA, sample or quotation. Include the product, application, quantity and destination.”
Is paper-grade FAS the same as TDO?
“They share the same confirmed chemical identity and CAS number, but Dasteck supplies TDO and paper-grade FAS as separate commercial product grades and lines.”
Why Is FAS Used for Deinked Pulp (DIP) Bleaching?
“Deinked pulp brightness is often limited by residual chromophores rather than lignin. FAS provides reductive bleaching under alkaline conditions. Fibre yield loss is generally small when process conditions are controlled. Actual brightness gain depends on furnish, ink system, consistency, pH, temperature, reaction time, metal ions and FAS dosage.”
Can FAS Be Used Together with Optical Brightening Agents (OBAs)?
“FAS and optical brightening agents can be used in the same overall process, but they are normally applied in separate stages. The extent of interaction depends on OBA chemistry, formulation additives and process conditions. Recommended sequence: FAS reductive bleaching, washing, then OBA application under the supplier's recommended conditions. Residual chemical levels should be confirmed before OBA addition.”
What About Safety and Storage?
“Thiourea dioxide is not harmless; its safety profile is relative to sodium dithionite and the current SDS must be followed. The SDS lists acute oral and inhalation toxicity Category 4, skin irritation Category 2, serious eye damage Category 1, STOT single exposure Category 3, STOT repeated exposure Category 2 and self-reactive Type G.”
What is the environmental impact of FAS?
“FAS has a different environmental profile from sodium dithionite. Overall impact depends on effluent volume, COD, nitrogen load and the mill treatment process; compare the complete process rather than assuming one chemical is universally lighter.”
Company details
- Founded
1992-11-12
Data formats & record details
Download this profile and inspect its supporting evidence.
- Entity ID
- urn:readyscan:entity:yantai-dasteck-chemicals-co-ltd-q141534379
- Material fingerprint
- fnv1a64:fb4403f4e142967d
- Entity revision
- fnv1a64:a448fcf9d18516ef
- Published
- 2026-10-24
- Modified
- 2026-10-24
- Source summary
- Yantai Dasteck Chemicals Co., Ltd.: “Manufacturer of Thiourea Dioxide (TDO, CAS 1758-73-2) for textile reduction, paper-grade Formamidine Sulfinic Acid (FAS) for pulp and paper, and Thiourea and Dicyandiamide for specialty use. Producing TDO since 1983, and a participating drafting unit of the Chinese industry standard for thiourea dioxide, HG/T 3258-2010.”