Isocyanate curing agent

Also in an invention of Frankel et al (Ref 40), a castable expl has been developed which, typically, consists of a polyester binder (20%) such as 3-(2,2,-dinitro-2f-fluoroethyl)-l,2-pro-panediol reacted with an isocyanate curing agent plus HMX (80%)... 

Isocyanate-based resins, in paper manufacture, 13 116 Isocyanate curing agents, 10 410 Isocyanate group, urethanes and, 22 36 Isocyanates... 

Pitch-polyurethane coatings are two-component materials containing polyol as the base resin and an isocyanate curing agent. They cure satisfactorily at temperatures as low as 0°C (BSC, undated). 

Maleic anhydride (72) when mixed with triphenylbismuthine in a ratio ranging from 1 1 to 1 1.5 provided a curing catalyst for a propellant composite comprising an oxidizer, isocyanate curing agent, and a hydroxy-terminated polymer binder. The resulting composite showed improved modulus and/or stress values for use with propellants <91 Ml 208-06). 

Adhesives used to bond acetal homopolymer to itself and to other materials, such as aluminum, steel, natural rubber, neoprene rubber, and Buna rubber, include polyester with isocyanate curing agent, rubber-based adhesives, phenolics, epoxies, modified epoxies, and vinyls. Solvent cementing... 

Other adhesives recommended hy ICI are 3M Company s Scotch Weld 2216 two-part epoxy, Amicon s Uniset A-359 one-part aluminum-filled epoxy, American Cyanamid s BR-89 one-part epoxy, Bostik s 7026 synthetic ruhher and 598-45 two-part adhesive, GE s Silgrip SR-573, and Goodyear s Vitel polyester with isocyanate curing agent. 

Oligoesters with acrylic ester end groups can be polymerized either directly or in blends with other monomers. The synthesis of the oligoesters from dicarboxylic acid and glycols in Fig. 7 has already been described with similar molar relationships for epoxide and isocyanate curing agents. The hydroxylic end groups are saturated with acrylic acid esters and then polymerized. 

The most widely used isocyanate curing agent is the dimer of tolylene 2,4-diisocyanate at the curing temperature (about 150°C) this dissociates into free isocyanate which effects cure ... 

A large number of multifunctional isocyanate curing agents are commercially available for crosslinking of the hydroxyl functional resin. These isocyarmte adducts are mostly derived from a limited number of aliphatic and aromatic monomeric isocyanates, whose stmctures can be seen in Figure 5-2. 

Isophorone diisocyanate (IPDI) based isocyanate curing agents confer very high durabihty to 2 component polyurethane systems, but this is offset by poor flexibility and low reaetivity. Hence IPDI adducts are usually combined with flexible hydroxy prepolymers in low bake applications. They are also used as partial replacements for the aromatic or aliphatic polyisocyanates. Compared to other diisocyanates, IPDI has the advantage that it has relatively low volatility, whilst still being a liquid. 

The major suppliers of isocyanate curing agents and their respective trade names can be seen in the following table. 

Structural adhesive types recommended are epoxy (up to 71°C), polyester with isocyanate-curing agent (up to 121°C), and cyanoacrylate (up to 82°C). Structural adhesives for bonding acetal copolymer to itself have yielded shear strengths of 4.1—5.5 MPa. Nonstructural adhesives are usually... 

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