Hardcoatings

Hardboards Hard coals Hardcoats Hard copy systems Hardenability Hardened fatty acid Hardeners... 

Plastic fibers Plastic films Plastic hardcoats Plasticity Plasticity index... 

In general, polycarbonate resins have fair chemical resistance to aqueous solutions of acids or bases, as well as to fats and oils. Chemical attack by amines or ammonium hydroxide occurs, however, and aUphatic and aromatic hydrocarbons promote crazing of stressed molded samples. Eor these reasons, care must be exercised in the choice of solvents for painting and coating operations. Eor sheet appHcations, polycarbonate is commonly coated with a sihcone—sihcate hardcoat which provides abrasion resistance as well as increased solvent resistance. Coated films are also available. 

Organosilicone Coating Products. SiHcone products are used in a large variety of coatiags appHcatioas most prominent amoag these are siHcoae pressure-seasitive adhesives (PSA), plastic hardcoats, and paper release coatiags (398,399). 

Hardcoats -silicone products [SILICON COMPOUNDS - SILICONES] (Vol 22)... 

Plastic bags Plastic beads Plastic bearing materials Plastic cements Plastic drums Plastic electronic packagf Plastic encapsulant Plastic fibers Plastic films Plastic hardcoats Plasticity Plasticity index Plasticity retention index Plasticization... 

The hardcoat is a silicone-silica composite prepared by hydrolysis of alkoxysilanes in the presence of water and colloidal silica, and can contain an alkoxysilylated UV absorber for protection of the polycarbonate. Adhesion of the topcoat to polycarbonate is provided by a primer, which is a solution of acrylic polymer. The primer is coated on polycarbonate and air dried to a 0.5 pm thick film. The topcoat is applied over the primer layer and air dried before curing at 130 °C for at least 30 min. 

This successful application of silicone hardcoat technology is leading to other applications for polycarbonate parts in automobile manufacturing, such as sunroofs or automobile windows. 

Medford, G. Pickett, J. Reynolds, C. The next generation of weatherable hardcoats for polycarbonate. PCI, 2001. (accessed October 2004). http //www.pcimag.com/pci/cda/article information/coverstory/bnpcoverstoryitem/ 0,29001,00 + en-uss 01dbc.html (accessed October 2004). 

D1SHP40L [GE Silicones] Primo used as adhesion promoter for weatherable abrasion-resistant silicone hardcoat on Lexan polycarbonate. 

PC sheet and injection molded parts may have a variety of coatings, including a range of hardcoats that enhance weathering, scratch, and abrasion resistance. 

Extreme operating conditions call for heavy duty materials, a case in point being the membrane switch material required for the ocean going yacht made by Tiara for which Autotype s Autotex XE (Extreme Environment) hard coated polyester film was used. Unlike traditional substrate materials Autotex XE can withstand high light levels, 85 °C operating temperatures and humidity levels of 85% relative humidity. Conventional films might delaminate, become brittle or flake under extreme conditions. Autotex XE film is polyester-based with specially constructed hardcoat and primer layers. 

The Effect of Non-radiation Factors on the Weathering of Silicone Hardcoats... 

Keywords Cracking Adhesion GMOD Polycarbonate Siloxane Topcoat Primer Automotive Glazing Coating Degradation Hardcoat Entitlement Fracture Mechanics Cycling Temperature Humidity Time-to-failure... 

Additionally, these experiments provide direction as to which factors are most critical in driving cracking failure in hardcoat systems. Discovery of the driving forces for crack propagation in these systems should enable a new model to be derived that would be a better predictor of real-world failure. 

Hardcoat systems of the type described in this paper can enable plastics to be used in applications for which they would otherwise be unsuitable, due to sensitivity of the plastic to UV degradation, chemical agents, or abrasion. The largest current market for these types of systems is automotive forward lighting applications, as protective coatings for clear polycarbonate headlamps. Other automotive applications include coatings for black polycarbonate side pillars and tinted... 

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