Polyamides fatty

The fatty polyamides are produced by reacting di- and polyfunctional amines with polybasic acids that result from condensations of unsaturated vegetable oil acids. The most commonly used amines are ethylene diamine and diethylene triamine. The dicarboxylic acids are synthesized by heating mixtures of unsaturated vegetable fatty acids. The starting materials may come from linseed, soybean, or tung (also called China wood) oil. The fatty acids are heated for several hours at 300°C. If a catalyst is used, the heating is done at a lower temperature. After condensation, the volatile fractions are removed by vacuum. The residues, called dimer acids, are then condensed with the amines. A formation of one such dimer acid from linoleic acid can be illustrated as follows  

The polyamide from the above shown dimer acid condensed with a diamine, like ethylene diamine, can be illustrated as follows  

Two types of fatty polyamides are available commercially, solid and liquid. The solid polymers are mostly linear condensation products of diacids and diamines that range in molecular weights from 2,000 to 15,000. The liquid ones are highly branched, low molecular weights materials produced by condensations of the dimer acids with triamines and even higher polyamines. 

---

In the adhesives area, thermoplastic, fatty polyamides are used in hot-melt and heat-seal adhesives for leather, paper, plastic and metal. Blends of EDA- and DETA-based polyamides are suggested for use in metal can seam sealants with improved toughness (234) pressure sensitive adhesives have been formulated with DETA-based polyamides (235) and anionic and cationic suspensoid adhesives are used as heat-seal coatings in paper converting (236). PIP and certain PIP derivatives are used with EDA in some appHcations (237). 

The molecular weights of fatty polyamides generally encompass the range of 3000-15,000. Anderson and Wheeler (10) evolved a relationship for number-average molecular weight determined by end-group analysis and viscosity so that molecular weight can be... 

When fatty polyamides of different melting points are mixed, the resulting melting point is nonlinear with respect to composition as demonstrated in Figure 1. Thus, a formulator has the ability to make many resin alloys. 

The fatty polyamides also demonstrate a high level of grease and oil resistance combined with a low order of irritation and toxicity... 

AblitsoIlL [Taiwan Surf.] Fatty polyamide sirfteners, antistats fin textiles. 

To a lesser extent, amine-terminated polybutadiene/acrylo-nitrile (ATBN) liquids are also used by epoxy formulators. This polymeric disecondary amine is employed in admixture with amines, amldoamlnes or fatty polyamides of choice (10, 11). Thus, one admixes chemical and polymeric amines to create a novel toughening or flexibilizing hardener package. 

At lesser rubber levels, heavy duty solventless coatings models based on dlethylenetrlamlne or fatty polyamide cures, showed elastomer-modification (10 phr rubber level) to advantage in Gardner impact, mandrel bend and corrosion-resistance testing (41). Impact testing (direct and reverse) gave 110 and 60 in-lbs, respectively for the rubber-modified fatty polyamide cured epoxy coating (14 days at R.T.), whereas a control formulation tested 10 in-lbs in each mode. 

Thicker epoxy-based coatings, highly flexibllized with amine-reactive nitrile liquid polymer, have been described by Mendelsohn (50) in which the flexibilizing hardener is comprised of an admixture of ATBN, fatty polyamide and boron trifluoride/amine complex. This coating ages well at 100°C and has excellent toughness/ flex with good abrasion and vibration absorption properties. 

Higher molecular weight epoxy resin hardeners such as fatty polyamides do not have the problems associated with amines and amine adducts. These reaction products of dimer and trlmer acids with polyfunctional amines provide films with fewer surface discontinuities. Polyamide cured epoxy coatings are more forgiving than amine cured epoxy coatings since they require less demanding surface preparation. Also, mix ratios are less critical for poly-amide/epoxy coatings (56). 

Fatty polyamides are used to cure epoxy resins where a more flexible product is required, particularly in adhesive and coating applications. An advantage of the system is that roughly similar quantities of... 

The family of synthetic polymeric materials with amide linkages in their backbones is laige. It includes synthetic linear aliphatic polyamides, which carry the generic name of nylon, aromatic polyamides, and fatty polyamides used in adhesives and coatings. In addition to the synthetic... 

Modified polyfunctional aliphatic amines, amidoamines and fatty polyamides are covered for both CTBN/epoxy adducts or ATBN hardener systems (42,44). Examples of systems based on selected epoxy-anhydride (45), an amine-ether (46) and Lewis acid/amine complexes (47) augment this information base. Dicyandiamide (1-cyano guanidine) containing systems alone (48) and with melamine (49) and various proprietary accelerators (50-53) are shown to serve as latent, one-component film and paste adhesives with an excellent balance of adhesive properties. 

FIGURE 3.30 Amine-terminated fatty polyamides for cure of epoxy resins. 

Fatty polyamide (Versamid , oldest of many trade names). A polymer formed by the condensation of a dibasic acid having a bulky side group and from 13- to 21-carbon chains, or the dimmer acids, C-36, with di- or polyamines. The commercially important dimmer acids are addition products of unsaturated C-18 fatty acids and can take several forms, giving different structures to the polyamides. They are used in hot-melt adhesives, inks, as epoxy flexibilizers and, in amine form, as curing agents for epoxies. Skeist I (ed) (1990, 1977, 1962) Handbook of adhesives. Van Nostrand Reinhold, New York. 

There are also available more complex synthetic aliphatic polyamides which are not fibre-forming but which have found use in such applications as adhesives and coatings. These products are known as fatty polyamides and are not generally regarded as nylons. 

The formation of a fatty polyamide from the above dimer is illustrated by the following reaction involving ethylenediamine ... 

Polyfunctional amines which are commonly used as curing agents for epoxy resins but which are of a rather different kind to those described above are the so-called fatty polyamides. These polymers, which are described in Section 9.3, are of low molecular weight (2000—5000) and are prepared by treating dimerized and trimerized fatty acids with ethylenediamine or diethylene triamine. Fatty polyamides are used to cure epoxy resins where a more flexible product is required, particularly in adhesive and coating applications. 

Aliphatic amines (a) Aromatic amines (b) Fatty polyamides (c) Anhydrides (HPA or NMA) (d)... 

---