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While the generic name polyamide is shared with nylons, the more well-known materials, nonnylon polyamides are unique in their raw materials, manufacturing processes, properties and applications. Only the presence of the amide linkage (–CONH–) in their structural backbones relates these two polymer groups. The nonnylons are composed of dimer acid–based (DAB) resins and epichlorohydrin copolymers.
The DAB polyamides are condensation products of the so-called dimer acids and homologs of either ethylenediamine (aliphatic diamines) for nonreactive polyamides or diethylenetriamine (higher ethyleneamines) for reactive polyamides. The nonreactive DAB polyamides are usually solid, higher-molecular-weight materials, while the reactive group is usually liquid, lower-molecular-weight resins.
Dimer acid–based polyamide resins are either reactive or nonreactive (i.e., they lack amine functionality). Reactive polyamides are utilized primarily as curing agents for epoxy resins used in surface coatings and adhesives. Nonreactive polyamides are used predominantly in hot-melt adhesives and printing inks.
World consumption of DAB polyamide resins will increase at an average annual rate of 2.0–2.5% during 2008–2013. Most of that growth will come from Asia Pacific. The economic crisis of 2008 and 2009 (by midyear) hit the DAB polyamide resins industry hard and consumption contracted significantly in the developed regions. A contraction in consumption of DAB resins for most applications was observed in 2008 and is expected in 2009. Industry sources believe economic recovery may only begin in 2010 followed by higher growth rates during 2011–2013 when markets may try to regain some lost volume.
Consumption of polyamide-epichlorohydrin resins, used primarily for wet-strength applications by the paper industry, is growing in the United States, Western Europe and China. Increased use of facial and kitchen tissues and better wet-strength performance are key factors behind expected average annual growth rates of 2.0–2.5% in the next five years. China will lead this growth on an average percentage basis; however, the United States and Western Europe will still dominate consumption on a volume basis.
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