IPDI

In the multistep production of IPDI, isophorone is first converted to 3-cyano-3,5,5-trknethylcyclohexanone (231—235), then hydrogenated and ammoniated to 3-aminomethyl-3,5,5-trknethyl-l-aminocyclohexane (1) (236,237), also known as isophorone diamine (IPDA). In the final step IPDA is phosgenated to yield IPDI (2) (238). Commercial production of IPDI began in the United States in 1992 with the startup of Olin s 7000 t/yr plant at Lake Charles, Louisiana (239), and the startup of Hbls integrated isophorone derivatives plant in Theodore, Alabama (240). Hbls has a worldwide capacity for IPDA of 40,000 t/yr. 

IPDI Technical Information Bulletin, Veba-Chemie AG, Gelsenkirchen-Buer, Germany, 1975. 

Powder coatings are formulated from the reaction product of trimethylolpropane and IPDI, blocked with caprolactam, and polyester polyols. The saturated polyester polyols are based on aromatic acid diols, neopentyl glycol, and trimellitic anhydride for further branching. To avoid the release of caprolactam in the curing reaction, systems based on IPDI dimer diols are used. 

Water-borne polyurethane coatings are formulated by incorporating ionic groups into the polymer backbone. These ionomers are dispersed in water through neutrali2ation. The experimental 1,12-dodecane diisocyanate (C12DI Du Pont) is especially well suited for the formation of water-borne polyurethanes because of its hydrophobicity (39). Cationomers are formed from IPDI, /V-methyIdiethan olamine, and poly(tetramethylene adipate diol)... 

In certain niche applications, aliphatic isocyanates, such as isophorone diisocyanate (IPDI), hexamethylene diisoeyanate (HDI), methylene 4,4 -biscyclo-hexylisocyanate (H12MDI), and polymeric versions of these diisocyanates, are used, e.g., in instances where light stability or reduced reactivity is needed. These isocyanates usually cost more than the aromatic diisocyanates. Thus, they are used in adhesive areas that can Justify the higher costs. 

Polyurethane dispersions (PUD s) are usually high-performance adhesives based on crystalline, hydrophobic polyester polyols, such as hexamethylene adipate, and aliphatic diisocyanates, such as methylene bis(cyclohexyl isocyanate) (H12MDI) or isophorone diisocyanate (IPDI). These PUD s are at the more expensive end of the waterborne adhesive market but provide excellent performance. 

Applications for blocked urethane adhesives are small. However, they may be used as flocking adhesives or as crosslinkers for solvent-borne adhesives. Blocked urethane adhesives are also used as splicing adhesives for belts. Blocked isocyanates based on TDI, IPDI, and derivatives of hexamethylene diisocyanate are most commonly commercially available. 

The ketimine of isophorone diamine is formed by reacting it with methyl isobutylketone, splitting off water in the process. When said ketimine is added to an isocyanate-terminated prepolymer based on IPDI, a semi-stable system is established with a pot life of several hours. The ketimine is a Schiff base and thus can react even in the absence of water. The complexities and advantages of this system are reviewed by Bock and Halpaap [75] ... 

Ionic internal emulsifiers, 237-238 Ionization methods, 408-409 IPDI, 219... 

Fur HTPB gebundene Raketentreib- und Sprengstoffe haben sich DDI und IPDI, fur GAP Diole N100 als Harter bewahrt. 

Toxicology. Isophorone diisocyanate (IPDI) is an irritant and sensitizer of the respiratory tract and the skin. 

A 50-year-old spray painter developed severe asthma soon after the introduction of a new paint containing IPDI. A bronchial challenge test with the paint gave a positive response. 

In another case, a spray painter developed tightness of the chest and dyspnea shortly after using a paint containing IPDI. The symptoms disappeared after a few days off work but recurred shortly after resumption of work. 

IPDI has been shown to provoke allergic dermatitis in exposed workers. ... 

Lachapelle JM, Lachapelle-Ketelaer MJ Cross-sensitivity between isophorone diamine and isophorone diisocyanate (IPDI). Contact Derm 5 55, 1979... 

A study in mice examined immune responses following topical exposure to three allergenic diisocyanates diphenylmethane-4,4 -diisocyanate (MDI), dicyclohexyl-methane-4,4 -diisocyanate (HMDI), and isophorone diisocyanate (IPDI). Contact and respiratory sensitizers induce differential immune responses in mice characteristic of Thl and Th2 T helper cell activation, respectively. All three chemicals are contact allergens. MDI is, in addition, a known human respiratory allergen. HMDI and IPDI did not produce an immunologic response in the mouse similar to MDI. These findings suggest that HMDI has much less potential to cause respiratory sensitization in humans than does MDI ... 

A key factor in the preparation of polyurethanes is the reactivity of the isocyanates. Aromatic diisocyanates are more reactive than aliphatic diisocyanates, and primary isocyanates react faster than secondary or tertiary isocyanates. The most important and commercially most readily accessible diisocyanates are aliphatic and colorless hexamethylene-1,6-diisocyanate (HDI), isophorone diisocyanate (IPDI),and aromatic, brownish colored diphenylmethane-4,4 -diiso-cyanate (MDI), 1,5-naphthalenediisocyanate, and a 4 1 mixture of 2,4- and 2,6-toluenediisocyanates (TDI). 

GAP, BAMO, AMMO, NIMO IPDI, TDI, PQD, HMDI, MAPO MAPO, TEA, MT-4 DOA, IDP, DOP... 

The most commonly employed curative for HTPB is TDI which is comparatively more reactive than other curatives except MDI. Due to this, the pot-life of TDI-cured propellant is only 4— 5h. IPDI is another curative which is preferred to TDI mainly on account of its slow reactivity resulting in extended pot-life, that is, 15-18h and low toxicity [91]. It is only recently that a bicurative system consisting of TDI and IPDI (70 30) has been developed and compared with TDI and IPDI-based systems. Compared with pot-life of TDI system (4—5h), bicurative system has got 7-8 h pot-life. At the same time, viscosity build-up is less in bicurative system revealing an edge over conventional TDI-based system for smooth processing of a propellant slurry [92]. 

FIGURE 2.7 Increase in viscosity of IPDI prcpolymer as function of reaction time at 125°C. 

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