Solvent release acrylic

Solvent-releasing acrylic sealants, 22 43 Solvent-releasing butyl sealants, 22 43-44 Solvent resistance, of polycarbonates, 79 799-801... 

Another class of acrylic sealants arc the solvent-releasing acrylics. Acrylic monomers are polymerized in a solvent. The natural adhesion of most of the solvent-releasing acrylics produces some of the best unprimed adhesion in the sealant industry. However, slow, continual cure generally produces large compression sets and limits their use to low movement applications. Also, the relatively high amounts of solvent and traces of acrylic monomer in these formulations limits their use to outdoor applications, usually in construction,... 

Acrylics. There are two principal classes of acryHc sealants latex acryHcs and solvent-release acryHcs. 

Yuksel N, Turkoglu M, Baykara T. Modelling of the solvent evaporation method for the preparation of controlled release acrylic microspheres using neural networks. J Microencapsulation 2000 17 541-51. 

Acrylics. There are two principal classes of acrylic sealants latex acrylics and solvent-release actylics. High molecular weight latex acrylic polymers are prepared by emulsion polymerization of alkyl esters of acrylic acid, The emulsion polymers are compounded inlo sealants by adding fillers, plasticizers, freeze-thaw stabilizers, thickeners, and adhesion promoters. As is true of the silicone lalex sealants, die acrylic latex sealants are easy to apply and clean with water. 

The level of CAB used with the polymer to obtain improved performance will vary from less than 1% to 50%. In some cases, one-tenth of 1% CAB will eliminate craters and improve flow out, whereas 15-25% is required to give good solvent release from a thermoplastic acrylic coating and up to 50% butyrate on the resin may be required to obtain good performance with an oil-free polyester resin. 

In a thermoplastic acrylic automotive coating, a CAB is used as the pigment dispersion medium and at 15% concentration based on polymer weight provides better sprayability, increased cold crack resistance, better pigment control, better solvent release, and improved exterior durability. (See Table IX.)... 

Resins. A large number of synthetic coating resins (e.g., alkyd, ketone, urea, maleate, and acrylic resins) are available for formulating nitrocellulose combination lacquers. Selection criteria include price, color, influence on solvent release, gloss, hardness, sandability, yellowing, and durability of the final coating. 

Molecular imprinted polymers MIPs exhibit predetermined enan-tioselectivity for a specific chiral molecnle, which is nsed as the chiral template dnring the imprinting process. Most MIPs are obtained by copolymerization from a mixture consisting of a fnnctional mono-nnsatn-rated (vinylic, acrylic, methacrylic) monomer, a di- or tri-nnsatnrated cross-linker (vinylic, acrylic, methacrylic), a chiral template (print molecnle) and a porogenic solvent to create a three-dimensional network. When removing the print molecnle, chiral cavities are released within the polymer network. The MIP will memorize the steric and functional binding featnres of the template molecnle. Therefore, inclusion of the enantiomers into the asymmetric cavities of this network can be assumed as... 

In the 2P process (4), a thin photopolymerizable liquid layer is cured in situ between a smooth substrate (cut from a polymer sheet or molded) and a master and stripped off to effect pattern transfer. The liquid layer ensures accurate, defect-free replication. Examples of solvent-free formulations include multifunctional acrylates with adhesion, wetting, and release agents. Free radical and cationic polymerization processes have been described (9). At the present disk volume levels, this method is claimed to be cost competitive with injection molding. 

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