Acrylic polyol polyurethane

Pieper R, Ekin A, Webster DC, Casse F, Callow JA, Callow M, E. (2007) A combinatorial approach to study the effect of acrylic polyol composition on the pProperties of crosslinked sUoxane-polyurethane fouling-release coatings. J Coatings Techn Res 4 453 61... 

Acrylic polyols represent a special group of amorphous polyols, of molecular weight (MW) of 8000-13000 daltons, obtained by radical copolymerisation of acrylic monomers (ternary or quaternary copolymers), such as acrylic or methacrylic acids and esters. The source of hydroxyl groups in these acrylic polyols is the utilisation in the radical copolymerisation reaction of hydroxyalkyl acrylates or hydroxyalkyl methacrylates [1,2] as comonomers. The acrylic polyols are used in high performance polyurethane (PU) coatings. 

Worley et al. (2003) described a method to develop biocidal polyurethane coatings. The authors developed a novel N-halamine monomer that can be copolymerized with a commercial waterborne acrylic polyol and a commercial isocyanate to produce a polyurethane coating. According to the authors, biocidal properties can be imparted to the coating by chlorinating the coating with a source... 

Aqueous two-component polyurethane systems for automotive topcoats are under development. Currently the automotive topcoats are made from solvent-based two-component or blocked one-component systems based on HDI trimer (Desmodur N) or IPDI trimer (Desmodur Z) or both in conjunction with an acrylic polyol. The polyurethane topcoats provide the vehicles with a tough and durable finish with excellent long-lasting glossy appearance ( wet look ) One-component aqueous dispersions are already used in electrodeposition primers and pigmented base coats. Soft-feel polyurethane coatings are increasingly used for instrument panels and seat covers. 

Ley DA, Fiori DE, Quinn RJ. Optimization of acrylic polyols for low VOC two-component water reducible polyurethane coatings using tertiary isocyanate crosslinkers. 

Various forms of polyurethane coatings are available. For maximum toughness and light stabihty, an acrylic polyol and a light-stable polyisocyanate, e.g. the HDI derivatives, may be applied (Thapliyal and Chandra, 1990). Polyisocyanates and derivatives are freqnently added to alkyd resins to improve their properties of toughness and adhesion. They suffer from many of the instabilities of the parent aUcyds. 

Resins. Most of the coalings for plastics formulated today utilize a flexi-biUzed polyol resin system that generally fits into one of two categories an acrylic or modified acrylic polyol or a condensation polymer (polyester, polyurethane, a combination of both through a physical blend, or modified resins that fall within the condensation polymer regime). 

If polyurethanes are used to entrap cells, the diffusion wiU depend on the polyol used to build the polyurethane since the polyol defines equilibrium moisture. Later in this chapter, we will discuss a number of entrapment systems, including acrylates and polysaccharides. Each has its own equilibrium moisture and therefore unique diffusion constant. Only polyurethanes, however, offer the opportunity to affect changes in the constants. Conventional hydrophilic polyurethanes have equilibrium moisture levels around 70%. It is possible, however, to increase the molecular weight of a polyol (an ethylene glycol of 1000 molecular weight) to 3000 or more. This increases the equilibrium moisture to greater than 90%. 

The radical containing an hydroxyethyl group which is formed (9.5), initiates the formation of polymeric chains which, by recombination, give hydroxy-telechelic polymers (reactions 9.6 and 9.7). Based on the principles mentioned various hydroxy-telechelic polymers were obtained by radical polymerisation of styrene [9], acrylonitrile [10], butyl acrylate or butadiene [10-14]. Of course, the oligo-polyols derived from styrene and acrylonitrile are solid and difficult to use in PU, but butyl acrylate and butadiene lead to liquid polymers with terminal hydroxyl groups, which are useful in polyurethane manufacture. 

Uses Polyurethane polyol used in soh/.-based systems modifier for acrylic, polyester, and alkyd resins high-solids coatings, machinery and equip, coatings, appliance coatings, automotive topcoats, paper and wood coatings, aerospace coatings Features Lower VOC... 

These foams can then be extended into the area of flame-retardant materials, where methyl oleate-polyesters were used as polyols in the synthesis of silicon-containing polyurethanes [89]. Despite not strictly being foams, methyl oleate, soybean and sunflower oils have also been investigated to produce semi-rigid flame retardant materials [90]. In this instance, they were brominated, acrylated and then radically copolymerized with styrene to form the polymeric material. 

Properties of hybrid dispersions prepared according to the different methods (la, lb and 2 - see Section 6.3.2) and based on the same polyol (PTMG 2000), but differing in the presence or absence of double bonds in the polyurethane-urea part of the hybrid, as well as of films and coatings made of them, are presented in Tables 6.21 and 6.22. All dispersions have a similar low level (2.0-3.3%) of coalescent and have the same structure of the acrylic/styrene part of the hybrid. Redox initiator was used in the synthesis of dispersions according to the method 2, and in all other dispersions presented in these tables a water-soluble initiator was applied. 

Binders in coatings include polyvinyl acetate and copolymers, polyvinyl butyral, polyesters, acrylic polymers, epoxies and polyurethanes (see Ethylene-vinyl acetate copolymers. Acrylic adhesives, Epoxide adhesives and Polyurethane), polyvinyl chloride, polyvinylidene fluoride and aUcyds (oxygen-convertible media containing polyol esters of long-chain unsaturated acids). All these potential film-formers can adhere through dispersion forces, (which are probably weak). Many binders, however, also contain... 

One-pack or two-pack polyurethane surface coatings, which may sometimes be combined with acrylic resin systems. The one-pack system, which has a long shelf life, is an adduct of resin with polyisocyanate dissolved in a moisture-free solvent. When applied to a surface the film cures and hardens, as moisture in the air reacts with the isocyanate groups in the resin. The two-pack system consists of a polyisocyanate (frequently derived from an aliphatic isocyanate monomer) and a polyol as separate components. Once the two components are mixed, the shelf life is very limited. 

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