Eastman Chemical is a leading manufacturer of thermoplastic, aromatic polyesters that are widely used in packaging and consumer products. In the 1970's Eastman Chemical invented water-dispersible polyester resins in order to allow for the benefits of polyesters such as toughness and optical clarity to be realized in waterborne formulations. These water-dispersible polyester resins are called AQ™ polyesters.
Eastman AQ™ polyesters are amorphous, aromatic polyester polymers that contain anionic sulfonate groups. Eastman AQ™ polyesters are produced by melt-phase polymerization of glycols and aromatic diacids. The 4 main components of these polyester resins are isophthalic acid, 5-sodiosulfoisophthalic acid, 1,4-cyclohexanedimethanol, and diethylene glycol. The properties of a particular grade of AQ™ polymer including glass transition temperature, molecular weight, and charge density will vary based on the ratio of these four monomers.
Eastman's AQ™ polyesters can be dispersed directly into warm water and will form stable polyester dispersions. When dispersed in water, AQ™ polyester resins spontaneously form small negatively charged aggregates. The size of these aggregates ranges from 10-30 nm in diameter. This small particle size lends to fast cure speeds and good penetration of water-based formulations. Polyester dispersions made with AQ™ Polyesters remain stably dispersed by electrostatic repulsion without the use of surfactants, organic solvents, emulsifiers, or inorganic bases. This provides better formulation flexibility and often times a cost savings. Pre-made waterborne dispersions of AQ™ polyester resins are commercially available under the trade name Eastek™.
The unique properties that Eastman AQ™ polyester resins and Eastek™ provide make them useful as a binder resin and film former in a variety of coating applications. The small particle size of AQ™ polyester resins in dispersion allows for good penetration of coatings into porous surfaces and the wide range of available glass transition temperatures available allows formulators control over film flexibility. In addition, the small nature of the particles allow for ultra fast cure speeds and smooth, glossy coatings.
Eastman AQ™ Polyester resins and Eastek™ can also be used in the manufacturing of water soluble composite materials for a variety of applications. Composite films are very popular in flexible packaging. When used as a tie layer coating for packaging films, AQ™ Polyester resins improve the recyclability of the composite. In addition, paper adhesives formulated with these resins are easily removed from the re-pulping process and improve efficiency.
For more information about a particular AQ™ Polyester Resin or Eastek™ Polyester Dispersion select one of the commercially available grades listed below.