Tetramethylxylene diisocyanate

Polyurethanes are frequently used in anticorrosion coatings. The R D drive of most coatings and resin producers is the reduction of the solvent content of the paint and resin systems. One method of achieving the environmental aims demanded by legislation in the PU coatings industry is to use oxazolidines which are suitable as latent hardeners to enable production of single-pack moisture activated PUs. The isocyanate chosen for this research is tetramethylxylene diisocyanate, which has been available commercially only since 1988. 19 refs. 

TMXDI TPU Triol Trowelable An abbreviation for meta-tetramethylxylene diisocyanate. Thermoplastic polyurethane. A polyol containing three reactive hydroxyl groups. Capable of being applied using a trowel and having thixotropic... 

Benzene, 1,3-bis(1-isocyanato-1-methylethyl)- BRN 2811946 EINECS 220474-4 Isocyanic acid, a,a,a, a -tetramethyl-m-xylylene Isocyanic acid, m-phenylene-diisopropylidene ester, m-Tetramethylxylene diisocyan-ate m-TMXDI Tetramethyl-m-xylylene diisocyanate. 

Aliphatic isocyanates are used whenever resistance to ultraviolet light is a critical concern. Examples of aliphatic isocyanates are hexamethylene diisocyanate, hydrogenated MDI, isophorone diisocyanate, and tetramethylxylene diisocyanate. Structures for these molecules are shown in Fig. 23. The aliphatic isocyanates are usually more expensive than aromatic isocyanates and find limited use in adhesive applications. Resistance to ultraviolet light is usually not a critical concern in adhesives because the substrate shields the adhesive from sunlight. 

Aqueous PU dispersions based on tetramethylxylene diisocyanate, polyesterols or polyetherols polyols and, as chain extender, an aliphatic diamine, were synthesised and their particle sizes, surface free energies, viscosities and dispersion stabilities and property/structure relationships determined. Coherent, dry, thin sheet materials were produced from these aqueous dispersions and characterised by DSC, DMTA and tensile testing. They were found to exhibit good mechanical properties similar to those of urethane-urea copolymers obtained by water-free methods. 31 refs. 

Although tetramethylxylene diisocyanate (TMXDI) also bears an aromatic structure like the TDI based products, it shows greater durability as the isocyanate group is not directly attached to the aromatic ring. 

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