Organotin poisoning, mistaken for "mental illness"?
First, let me show you a news story.
I. What is organotin?
Organotin_Self Description
Organotin compounds are metal-organic compounds formed by the direct combination of tin and carbon, the general formula is: RnSnX(4-n) (n=1-4, R is generally alkyl or aromatic group, X can be inorganic or organic acid root, or fluorine, chlorine, bromine, iodine, oxygen, etc.).
Organotin_Uses
It is used as a catalyst (dibutyltin, stannous octanoate), stabilizer (such as dimethyltin, dioctyltin, tetraphenyltin), agricultural insecticide, fungicide (such as dibutyltin, tributyltin, triphenyltin) and coating and anti-mold agent for everyday products.
Why is it used?
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1、 Organotin catalyst is the most widely used metal catalyst in polyurethane at present, and there are many domestic and foreign manufacturers of it. Organotin catalysts have good catalytic activity in both pre-polymerization and film curing of polyurethane.
2, organotin heat stabilizer has good thermal stability, weatherability and transparency, is currently the most widely used, one of the best heat stabilizers.
Second, the harm
Tin itself is a non-toxic metal, metal tin compounds have inorganic tin and organic tin two categories, inorganic tin compounds are mostly low or non-toxic, a few animals have obvious toxicity; and organic tin because of its wide range of use, a variety of forms, and toxicity and biological effects and form have a close relationship, has attracted the general attention of governments and environmental protection organizations around the world.
The toxicity of organotin is related to its molecular structure, and only when the Sn atom is connected to the C atom does it show toxicity. In the same series of organotin compounds, the higher the number of substituted alkyl groups, the greater the toxicity, but when the number of substituted alkyl groups increases to a certain extent, the toxicity decreases instead due to excessive molecular volume.
Toxicity size.
R3SnX＞R2SnX2＞RSnX3>>R4Sn≈SnX4
The main damage of organotin compounds to living organisms
The central nervous system causes cerebral white matter edema, oxidative phosphorylation processes in cellular energy utilization are blocked, the thymus and lymphatic system are inhibited, cellular immunity is impaired, hormone secretion is inhibited causing diabetes and hyperlipidemia, etc. Toxicity to humans, local irritation of the skin, respiratory tract, cornea, through the skin or brain edema can cause systemic poisoning, and even death. 1958 France due to the use of agents containing triethyltin treatment of skin disease caused a 10% mortality rate (known as the Stellenon incident).
Third, the relevant restrictions and regulations
For the restrictions on organotin compounds, the EU has previously issued 89/677/EEC, 1999/51/EC and 2002/61/EC, stipulating that organotin mixtures used as free association paint (free association paint) in the biocide, can not be sold on the market. This amendment is based on the original 76/769/EEC Directive Appendix I, Article 21, the following provisions were added to the content of.
Dibutyl (DBT) compounds
From January 1, 2012, DBT compounds with a tin content of more than 0.1 wt% shall not be used in mixtures or articles supplied to the public.
1, one-component and two-component room temperature vulcanization (RTV) sealants (RTV-1 and RTV-2 sealants) and adhesives.
2, articles as catalysts, whose paints and coatings contain DBT compounds.
3, soft polyvinyl chloride (PVC) profiles, whether they are inherently soft or co-extruded with hard PVC.
4, fabrics for outdoor use, the surface of which is covered with PVC containing DBT compounds as a stabilizer.
5. Pipes, drains and appliances for outdoor rainwater, as well as roof and sidewall covering materials.
Dioctyl (DOT) compounds
Effective January 1, 2012, DOT compounds containing more than 0.1 wt% tin shall not be used in the following items supplied to or used by the public.
Textiles designed to come into contact with skin; gloves; shoes or corresponding parts on shoes designed to come into contact with skin; wall and roof coverings; child care products; feminine hygiene products; diapers; and two-component room temperature vulcanization molds (RTV-2 molds).
Organic tin compounds have become an environmental pollutant that has caused widespread concern among governments and environmental protection organizations around the world, and many countries have included them in the priority pollution control "blacklist".
Four, OEKO ecological textile requirements
According to the description of OEKO-TEX100 2017, the different types of organotin are restricted, mainly as follows.
V. Testing principle
The analysis and testing of organic tin compounds at home and abroad are mainly focused on textiles, food and environmental samples, and the testing of organic tin compounds in plastic products is still relatively small.
The samples were extracted with suitable solvents and ultrasonicated to extract the organotin compounds therein, the extracts were derivatized and extracted to the organic phase, and the organic phase was taken for GC-MS analysis, and the dibutyltin chloride, monobutyltin chloride, triethyltin chloride, triphenyltin chloride, tributyltin chloride, tripropyltin chloride, diphenyltin chloride, tetrabutyltin, dioctyltin chloride and monophenyltin in the samples were analyzed by external standard method. Stannous chloride and other organic tin compounds for qualitative and quantitative analysis.
VI. Textile, leather and footwear related standards
VII. Recommendations
The process of producing and using organotin should be sealed and piped, and should be operated under negative pressure to avoid manual operation. Organotin compounds are heavier than air, so the exhaust equipment should be set below.
The gases of organotin substances are easily adsorbed by porous substances such as concrete, wood and cotton fabric, and are not easily removed. Because, the production workshop floor requires polished, walls, desktops, etc. need to be painted smooth and easy to flush. If the workshop polyester and cotton are contaminated, use 5% bleach or potassium permanganate solution to clean.
Do a good job of personal protection, work clothes, gloves and other protective equipment should not use cotton fabrics, but also should not use rubber products (because organic tin can be permeable). It is advisable to use plastic or synthetic fiber-type materials.
High concentrations of organotin compounds are very harmful to humans and the environment, so the detection of organotin compounds should not be ignored.
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