MOCA Replacement

Thin Film Partners associates have filed patent applications for eight different approaches to safe curing agents to replace MOCA. We seek partners to assist in commercializing MOCA replacements. Our associates were members of the original Polaroid team that developed Polacure and Polamine curing agents in the 1970s.


The primary curing agent for polyurethane elastomers for cast part and coating applications over the last 30 years has been 4,4’-Methylene-bisorthochloroanaline, commonly known as MOCA. The structure is shown below.

MOCA has held this predominant position due to a combination of processing, cost, and end product properties, in spite of serious and well known toxicity in test animals and humans. Advantages:

  • roduces high performance elastomers. Tensile strength, tear strength,
  • elongation.
  • Relatively low melting point of 105-110 C for ease of mixing into elastomer
  • formulations.
  • Has ~1hr processing window or “pot life”.
  • Low cost. Single step process with low cost raw materials.
  • Shortcomings:
  • MOCA animal carcinogen effects known since 1960’s.
  • Similar toxicity in humans hotly debated since the 1970’s.
  • European regulatory action to ban MOCA due to human and animal

toxicity as of November 22, 2017. Other jurisdictions in US and Japan are following.

These obvious shortcomings have inspired a great deal of work by many investigators, over a 30 year period, to develop a safe drop-in replacement for MOCA. None of these efforts have been altogether successful.

Summary of the Invention

The basis of this invention is the condensation of low cost odd chain or odd/even chain diol and triol linkers to produce ortho and para and particularly paraaminobenzoate crosslinkers for polyurethane and other chain extending/crosslinking applications. The para derivatives are easily prepared in two steps by direct esterification of the alcohol with p-nitrobenzoic acid and reduction of the nitro groups.

Please contact, Warren Boomer, of Thin Film Partners if you wish to partner in the commercialization of safe, non-toxic curing agents for Polyurethanes.