1. Laws and Regulations

The EU approved Directive 2009/425/EC on 28 May2009 to further restrict the use of organotin compounds. The decision is also one of two latest technology supplements to Directive 76/769/EEC (the other is 2009/424/EC approved on the same day).

It is worth noting that from 1 June 2009, the appendix VXII of REACH regulations shall replace Appendix I of 76/769/EEC, but both contents are the same. Thus, although the 76/769/EEC directive has been revoked, the content of its provisions is still valid but just transfer to the appendix VXII of REACH regulation.

To restrict organotin compounds, the European Union successively issued 89/677/EEC, 1999/51/EC and 2002/62/EC previously, which stated that the provisions of the organotin mixture used as biocides in free association paints should not sell on the market. The amendment supplements the following contents on the basis of Article 21 of Appendix I of original Directive 76/769/EEC:

1.1 Tri-substituted organotin compounds

From 1 July 2010, tri-substituted organotin compounds such as tributyltin (TBT) and triphenyltin (TPT), shall not be used in mixtures and articles where the concentration is greater than the equivalent of 0.1% by weight of tin,

1.2 Dibutyltin (DBT) compounds

From 1 January 2012, dibutyltin (DBT) compounds shall not be used in mixtures and articles for supply to the general public where the concentration is greater than the equivalent of 0.1% by weight of tin.

For the following articles and mixtures supplying to the general public, the effective date is 1 January 2015:

One-component and two-component room temperature vulcanisation sealants (RTV-1 and RTV-2 sealants) and adhesives;

Paints and coatings containing DBT compounds as catalysts when applied on articles;

Soft polyvinyl chloride (PVC) profiles whether by themselves or coextruded with hard PVC;

Fabrics coated with PVC containing DBT compounds as stabilizers when intended for outdoor applications;

Outdoor rainwater pipes, gutters and fittings, as well as covering material for roofing and facades.

This measure does not apply to materials and articles regulated under Regulation (EC) No 1935/2004 of the European Parliament and of the Council of 27 October 2004 on materials and articles intended to come into contact with food.

1.3 Dioctyltin (DOT) compounds

From 1 January 2012, dioctyltin (DOT) compounds shall not be used in the following articles for supply to, or use by, the general public, where the concentration is greater than the equivalent of 0.1% by weight of tin:

Textile articles intended to come into contact with the skin;

Gloves;

Footwear or part of footwear intended to come into contact with the skin;

Wall and floor coverings;

Childcare articles;

Female hygiene products;

Nappies;

Two-component room temperature vulcanisation moulding kits (RTV-2 moulding kits).

2. Application

Organotin compounds are mainly used as PVC stabilizer, and also used as agricultural fungicides, antimildew agent in paints etc., underwater antifouling agent and antiseptic agent and so on.

3. Risk

Tri-substitude compounds were previously widely used in antifouling paints on ships. However, such paints were found to pose risks foraquatic organisms through endocrine disruptive effects.Organotin compounds are generally absorbed through respiratory tract, and the absorption extent through skin and digestive tract differs with their species. The early feeling of poisoning is only a headache, dizziness and fatigue, which easily misdiagnosed as upper respiratory infection. Acute organotin poisoning is mainly performed as brain disease with different clinical manifestations for the different target sites affected by the toxicity of organotin compounds.

Organotin compounds, which may cause acute toxic encephalopathy, mainly include: trimethyltin, triethyltin, bis(triethyltin) sulfate, tributyltin, triphenyltin, tetraethyltin, tetrabutyltin, tetraphenyltin and so on.