Acrylics coatings

General Properties. Paints containing acrylic resins as binders have been known ince the 1930s. They are now one of the largest product classes in the paint and coatings sector. 

Polyacrylates as binders consist of copolymers of acrylate and methacrylate esters. Other unsaturated monomers (e.g., styrene and vinyltoluene) may also be incorporated, but usually to a lesser extent. Copolymers formed exclusively from acrylates and/or methacrylates are termed straight acrylics. The comonomers differ as regards the alcohol residues of the ester group, which also allow incorporation of additional functional groups. Choice of suitable monomers allows wide variation of the physical and chemical properties of the resulting polymer. Hydrophilicity, hydrophobic-ity, acid base properties as well as can be adjusted resins containing hydroxyl, amine, epoxy, or isocyanate groups can also be produced. 

The resin products may be solids, solutions in organic solvents or water, emulsions, or dispersions. 

Acrylate resins have several advantages over other paint binders [2.40]-[2.44]  

1) Polyacrylates are only slightly attacked by chemicals, and confer a high degree of resistance to 

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Methyl ethyl ketone may also he produced hy the catalyzed dehydrogenation of sec-hutanol over zinc oxide or brass at about 500°C. The yield from this process is approximately 95%. MEK is used mainly as a solvent in vinyl and acrylic coatings, in nitrocellulose lacquers, and in adhesives. It is a selective solvent in dewaxing lubricating oils where it dissolves the oil and leaves out the wax. MEK is also used to synthesize various compounds such as methyl ethyl ketone peroxide, a polymerization catalyst used to form acrylic and polyester polymers and methyl pentynol by reacting with acetylene ... 

Chlorinated rubber is soluble in aromatic solvents, and paints made from it dry by solvent evaporation alone. In contrast to the vinyls, there is less difficulty in formulating systems that are suitable for brush application. It has excellent resistance to a wide range of chemicals and to water, but as it is extremely brittle it needs to be plasticised. To preserve chemical resistance it is necessary to use inert plasticisers such as chlorinated paraffin wax. Due to the presence of ozone depleting solvents, chlorinated rubber coatings are being phased out and largely replaced by vinyl acrylic coatings which have very similar performance and can be formulated from lower aromatic or aliphatic solvents. 

Poly (p-nitrophenyl acrylate)-coated wide-pore glass (WPG) was also used as an activated carrier for the immobilization of biospecific ligands and enzymes, A detailed description of properties of these sorbents and catalysts as well as some specific features of their functioning is given in Sect. 6. 

Immobilization of A and B blood group oligosaccharide haptens and preparation of immunoadsorbents with specificity to anti-A and anti-B antibodies has been carried out with the use of poly acrylate-coated PG (WPG-PA) [124]. Prespacered A and B-trisaccharide-fl-aminopropylglycosides were used for the synthesis. WPG-PA (1 g) quantitatively binds both haptens (2 pinole) whereas some other activated affinity supports (for example, CNBr-Sepharose 4B) do not. On the other hand, glycidoxypropyl-silica binds prespacered haptens completely but these materials reveal no specific adsorptivity. 

Figure 9. UV-visible absorption spectra of a stabilized PVC plate, with or without a 70 yin UV cured epoxy-acrylate coating, before and after QUV aging at 40°C...

Uses Solvent in nitrocellulose coatings, vinyl films and Glyptal resins paint removers cements and adhesives organic synthesis manufacture of smokeless powders and colorless synthetic resins preparation of 2-butanol, butane, and amines cleaning fluids printing catalyst carrier acrylic coatings. 

Figure 7. Nyquist plots - chlorine containing vinyl acrylic coating alternatively immersed in 3 NaCl.

Polyurethane-acrylic coatings with interpenetrating polymer networks (IPNs) were synthesized from a two-component polyurethane (PU) and an unsaturated urethane-modified acrylic copolymer. The two-component PU was prepared from hydroxyethylacrylate-butylmethacrylate copolymer with or without reacting with c-caprolactonc and cured with an aliphatic polyisocyanate. The unsaturated acrylic copolymer was made from the same hydroxy-functional acrylic copolymer modified with isocyanatoethyl methacrylate. IPNs were prepared simultaneously from the two-polymer systems at various ratios. The IPNs were characterized by their mechanical properties and glass transition temperatures. 

Uses. As industrial solvents for adhesives, lacquers, paint removers, and acrylic coatings... 

Fig. 40. Indentation hardness, at A, 19 Jim B, 47 Jim and C, 108 Jim thickness, and Young s modulus, E, of a free film (as functions of temperature) of an acrylic coating (249). These results show the dependence of thickness that occurs with thin films. To convert MPa to psi, multiply by 145.

A relatively new method uses 172 or 222 nm excimer radiation in nitrogen atmosphere.i The irradiation causes a surface cure of the acrylate coating similar to milk skim in appearance. In the second step, the coating is fully cured by UV or EB. 

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