Toluene diisocyanate

Описание

Toluene diisocyanate (TDI) is an aromatic diisocyanate that is a clear, pale yellow liquid with a sharp, pungent odor, which is insoluble in water and miscible with most common organic solvents. TDI (CAS No. 26471-62-5) consists of two isomers: toluene-2,4-diisocyanate (2,4-TDI) (CAS No. 584- 84-9) and toluene-2,6-diisocyanate (2,6-TDI) (CAS No. 91- 08-7), which is commercially produced in different ratios. The most common ratio is 80% 2,4-TDI/20% 2,6 TDI. TDI is widely used and accounted for 34% of the global isocyanate market in 2000.

Химические свойства

Toluene diisocyanate is a colorless, yellow, or dark liquid or solid. It has a sweet, fruity, pungent odor. Toluene diisocyanate (technical, 26471-62-5) is an 80: 20 mixture of 2,4-and 2,6-isomers. A solid above 71/F/22℃. The Odor Threshold is 0.4-2.14 ppm.

Использование

Toluene diisocyanates are used primarily to manufacture flexible polyurethane foams for use in furniture, bedding, and automotive and airline seats. Other, smaller uses are for polyurethane elastomers (for automobile bumper covers, industrial rollers, sport soles and boots, and mechanical goods) and coatings (for automotive refinishing, wood finishes, and high-performance anti-corrosion coatings)(ICIS 2009). Toluene diisocyanate–based rigid polyurethane foam is used in household refrigerators and for residential sheathing or commercial roofing in board or laminate form (IARC 1986). “Pour-inplace” or “spray-in” rigid foam is used as insulation for truck trailers, railroad freight cars, and cargo containers. Polyurethane-modified alkyds contain approximately 6% to 7% isocyanate, mostly toluene diisocyanates, and are used as coating materials, such as floor finishes, wood finishes, and paints. Moisture-curing coatings are used as wood and concrete sealants and floor finishes. Aircraft, truck, and passenger-car coatings often are composed of toluene diisocyanate prepolymer systems. Castable urethane elastomers are used in applications requiring strength, flexibility, and shock absorption, and are resistant to oil, solvents, and ultraviolet radiation. They are used in adhesive and sealant compounds and in automobile parts, shoe soles,rollerskate wheels, pond liners, and blood bags. They are also used inoil fields and mines. Certain elastomer products are produced from the pure 2,4 isomer rather than the 80:20 mixture.

Общее описание

A clear colorless to pale yellow liquid with a pungent odor. Denser than water. Burns, but may be difficult to ignite. Vapors are heavier than air. Vapors irritate the respiratory system. Toxic under prolonged exposure to vapor in low concentrations or short exposure to high concentrations of vapor. Carcinogenic. Produces toxic oxides of nitrogen during combustion. Used to make polyurethane foams and paints.

Реакции воздуха и воды

Reaction with water liberates carbon dioxide.

Профиль реактивности

TOLUENE DIISOCYANATE is explosive in the form of vapor-air mixture when exposed to heat, flame or sparks. Potentially violent polymerization reaction with strong bases or acyl chlorides. Reaction with aniline may generate enough heat to ignite unreacted portion and surrounding materials. Reaction with water liberates carbon dioxide. Potential explosion if stored in polyethylene containers due to absorption of water through the plastic. Emits toxic fumes of oxides of nitrogen when heated to decomposition[Lewis, 3rd ed., 1993, p. 1251].

Пожароопасность

TOLUENE DIISOCYANATE is combustible.

Контактные аллергены

Toluene diisocyanate is a mixture of 2,4-TDI and 2,6- TDI. It is used in the manufacture of various polyurethane products: elastic and rigid foams, paints, lacquers, adhesives, binding agents, synthetics rubbers, and elastomeric fibers.

Профиль безопасности

Confirmed carcinogen with experimental carcinogenic and neoplastigenic data. Poison by inhalation. Moderately toxic by ingestion. Severe skin irritant. Human mutation data reported. Capable of producing severe dermatitis and bronchal spasm. A common air contaminant. A flammable liquid when exposed to heat or flame. Explosive in the form of vapor when exposed to heat or flame. To fight fire, use dry chemical, COa. Potentially violent polymerization reaction with bases or acyl chlorides. Reaction with water releases carbon dioxide. Storage in polyethylene containers is hazardous due to absorption of water through the plastic. When heated to decomposition it emits highly toxic fumes of NOx. See also IS0CYANATES .

Возможный контакт

Toluene diisocyanate is used in the production of polyurethane flexible foams, coatings, paints, and elastomers. It is more widely used than MDI (diphenylmethane diisocyanate). Polyurethanes are formed by the reaction of isocyanates with polyhydroxy compounds. Since the reaction proceeds rapidly at room temperature, the reactants must be mixed in pots or spray guns just before use. These resins can be produced with various physical properties, for example, hard, flexible, semirigid foams; and have found many uses, for example, upholstery padding; thermal insulation; molds, surface coatings; shoe inner soles; and in rubbers, adhesives, paints, and textile finishes. Because of TDI’s high volatility, exposure can occur in all phases of its manufacture and use. MDI has a much lower volatility, and problems generally arise only in spray applications.

Канцерогенность

Toluene diisocyanates are reasonably anticipated to be human carcinogens based on sufficient evidence of carcinogenicity from studies in experimental animals.

Перевозки

UN2078 Toluene diisocyanate, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Несовместимости

May form explosive mixture with air. Isocyanates are highly flammable and reactive with many compounds, even with themselves. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Reaction with moist air, water or alcohols may form amines and insoluble polyureas and react exothermically, releasing toxic, corrosive or flammable gases, including carbon dioxide; and, at the same time, may generate a violent release of heat increasing the concentration of fumes in the air. Incompatible with amines, aldehydes, alkali metals, ammonia, carboxylic acids, caprolactum, alkaline materials, glycols, ketones, mercaptans, hydrides, organotin catalysts, phenols, strong acids, strong bases, strong reducing agents such as hydrides, urethanes, and ureas. Elevated temperatures or contact with acids, bases, tertiary amines, and acyl-chlorides may cause explosive polymerization. Attacks some plastics, rubber and coatings. Contact with metals may evolve flammable hydrogen gas. May accumulate static electrical charges, and may cause ignition of its vapors.

Утилизация отходов

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Controlled incineration (oxides of nitrogen are removed from the effluent gas by scrubbers and/or thermal devices). In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.