Polyurethane powder

Polyurethane coatings are strong and durable. They can be found on surfaces that need to be flexible, abrasion resistant, and chemical resistant, such as dance floors and bowling alleys. Water-based coatings are often used on airplanes and other transportation equipment. Polyurethane powder coatings are also used on fluorescent lights, refrigerators, car wheels and trim, lawnmowers, patio furniture, and ornamental iron. 

OH branched, low molecular mass, hydroxy-functional 1000- 5000 melamine resins, free/blocked polyisocyanate resins automotive/ industrial paints, polyurethane/ powder coatings... 

Hot phenol is an unpleasant by-product to release from a paint and polyisocyanates blocked with phenols have not met with widespread use in coatings. However, the use of polyisocyanates blocked with e-caprolactam is a popular route to polyurethane powder coatings. 

The leading powder is epoxy resin, applied 1 to 50 mils thick this is used for corrosion resistance in auto underbodies, steel rebars for concrete, petroleum industry, appliances, and citrus food cans. Epoxy-polyester powders are more resistant to yellowing and are used 1 to 20 nuls thick for aluminum wheels and architectnral trim. Polyester-polyurethane powders are smooth, flexible, and weather resistant 1 to 3 mil films are used for auto trim, steel wheels, fighting fixtures, patio furniture, and appliances. 

Pilch-Pitera B. Polyurethane powder coatings crosshnked with aUophanate structures containing polyisocyanates. J Appl Polym Sci 2010 116(6) 3613-20. 

Plummer K, Vasquez M, Majewski C, Hopkinson N. Study into the recyclability of a thermoplastic polyurethane powder for use in laser sintering. Proc Inst Mech Eng Part B J Eng Manuf 2012. [online] Available at http //pib.sagepub.eom/content/early/2012/03/ 30/0954405412440066.fuU.pdf. [accessed 27.01.12]. 

An example of the application of blocked polyisocyanate technology is polyurethane powder coatings. These coatings typically consist of a solid, blocked isocyanate and a solid polyester resin, melt blended with pigments and additives, extruded and then pulverized. The block polyisocyanate technique can also be used to formulate waterborne polyurethane coatings [8]. 

Blocked NCO + Polyol (polyurethane) Powder stoving Can and coil coatings, maintenance coatings, adhesives for metals... 

Superabsorbents. Water-sweUable polymers are used extensively in consumer articles and for industrial appUcations. Most of these polymers are cross-linked acryUc copolymers of metal salts of acryUc acid and acrylamide or other monomers such as 2-acrylamido-2-methylpropanesulfonic acid. These hydrogel forming systems can have high gel strength as measured by the shear modulus (134). Sometimes inorganic water-insoluble powder is blended with the polymer to increase gel strength (135). Patents describe processes for making cross-linked polyurethane foams which contain superabsorbent polymers (136,137). 

Only a few commercial uses for TDA per se have been found. In epoxy curing appHcations, 2,4- I DA has been used as a component of a eutectic mixture with short chain aUphatic glycidal ether resins (46) as well as by itself (46,47) TDA (46) and single isomers (47) are also used as amine curatives. TDA can be used as a chain extender in polyurethanes (48,49). TDA is cited as a monomer in making aromatic polymers with unique properties, eg, amorphous polyamides (50), powdered polyamides (51), and low melting, whoUy aromatic polyamides (52). 

This includes wire enamels on a base of polyvinyl formal, polyurethane or epoxy resins as well as moulding powder plastics on phenol-formaldehyde and similar binders, with cellulose fillers, laminated plastics on paper and cotton cloth base, triacetate cellulose films, films and fibres of polyethylene terephthalate. 

Thin coatings consist of paints and varnishes, which are applied as liquids or powdered resin with a thickness of about 0.5 mm [e.g., epoxy resin (EP) [2]]. Typical thick coatings are bituminous materials [3] and polyolefins [e.g., polyethylene (PE) [4]], thick coating resin combinations [e.g., EP tar and polyurethane (PUR) tar [2]] as well as heat-shrinkable sleeves and tape systems [5]. 

Chandalia, K. et al.. In Storey, R. and Thames, S. (Eds.), Proceedings of 28th International Waterborne, High-Solids and Powder Coating Symposium. New Orleans, LA, 2001, p. 77. Woods, G., The ICI Polyurethanes Book. Wiley, New York, NY, 1987. 

Siloxane containing polyester, poly(alkylene oxide) and polystyrene type copolymers have been used to improve the heat resistance, lubricity and flow properties of epoxy resin powder coatings 43). Thermally stable polyester-polysiloxane segmented copolymers have been shown to improve the flow, antifriction properties and scratch resistance of acrylic based auto repair lacquers 408). Organohydroxy-terminated siloxanes are also effective internal mold release agents in polyurethane reaction injection molding processes 409). 

The mono- and disubstituted organotins considered here are used as stabilizers in PVC or as catalysts for the production of electrodeposited coatings (mainly in motor vehicle primers), sihcone rubbers, esterification and powder coatings, and polyurethanes, as well as for coating glass. 

---