Scratch resistance improvement

In plastics applications, wollastonite reinforces, increases scratch resistance, improves thermal stability, increases welding strength, and decreases warpage and... 

For scratch resistance improvement of organic surfaces also nano-composites are of interest. In a composite nano-scale boehmite or y-aluminia particles of about 15 nm diameter have been used as catalysts for epoxy groups linked to hydrolyseable and condensable silanes. Epoxy polymerization preferably takes place around the nanoparticles and additionally =Si-0-Al= bonds are formed between the silanes and the alumina surface [486]. It seems that the nano-particles, only 5% in volume fraction, are flexibly suspended in an inorganic-organic network. Such systems can be produced as transparent coatings and cured at relatively low temperatures of 90 to 120°C to high performance scratch resistant layers. 

The small amount of other additives include heat stabilizers, UV stabilizers, mold-release agents/lubricants, paint-adhesion promoters, mar and scratch-resistance improving additive, etc. 

Figure 1 shows that the random animal skin texture can delay the onset scratch visibihty, i.e., improve the scratch performance for both System A and System B. For a larger size scratch tip, it also shows that a similar delay (Fig. 2). While the level of scratch resistance improvement varies, the test residts on technical grain surface samples also show a similar effect (not shown).

The constmction of the E-111 windshield shown in Eigure 8 replaced a glass—silicone laminate previously used. The all-plastic windshield has improved impact resistance so that it is birdproof to 250 m/s (33). In this instance, the scratch resistance of glass was waived to obtain the impact performance at the allowed weight. 

Scratch resistance of polymer from DADC is improved by novel mixtures of peroxide initiators such as 5% isopropyl percarbonate with 3.5% benzoyl peroxide (16). In order to force completion of polymerization and attain the best scratch resistance in lenses, uv radiation is appHed (17). Eyeglass lenses can be made by prepolymerization in molds followed by removal for final thermal cross-linking (18). 

Polyimides having the structure shown are used as coatings on glass and plastics to improve scratch resistance. How would you synthesize n poJvimide (See Problem 21.53.)... 

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). 

Sputtering i s presently the maj or thin-film process for the production of deicing coatings. The coating is satisfactory from an optical standpoint although transmission could still be improved, but it has poor scratch resistance and must be sandwiched between the two layers of safety glass. The CVD oxides films shown in Table 16.1 are particularly attractive since they are inherently abrasion resistant and could be used on the outer surface of the glass. 

The use of silicone, at a level of 2% to less than 10%, helps reduce the coefficient of friction and correspondingly improves the scratch resistance. 

For example, the scratch resistance of talc-filled TPOs modified with 2-3% silicone from masterbatches is significantly improved and visible whitening is suppressed under conditions that damage the same TPO without silicone. Paintability must be verified but a low silicone level (2.5% for example) does not affect paintability, and weathering resistance increases showing less change in aspect than the control without silicone. 

UV and/or heat stabilized improved colour and gloss retention cold-temperature ductility and flexibility soft touch food contact low hardness conductive high stiffness high-impact ultra-high impact high modulus colourable scratch resistant paint performance electrostatic painting. .. 

A two-colour automated injection-moulding machine from Husky allows simultaneous-shot injection moulding of a two-colour instrument panel for the 2005 Ford Mustang. The process reduces squeaks and rattles, equipment costs, production time and scrap, and improves scratch resistance. 

A minimum chromium concentration of approximately 11% is typical for stainless steel. As more chromium is added, corrosion resistance improves. Concentrations of chromium >20% are found in some alloys. Chromium addition leads to the formation of a tight-forming oxide film on the surface of the metal. This stable film is self-healing, which means that the film will reform if scratched or broken. This oxide is quite resistant to attack by acids, bases, organic compounds, and inorganic salts. 

Molds for nylon RIM systems can be made from a wide variety of materials including steel, aluminum, klrkslte and nickel. Chrome and nickel plating has also been widely used to improve the scratch resistance of molds made of softer materials. At this writing, no epoxy tooling system has been demonstrated that will produce more than a few parts before failing. Development work continues in this area. 

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