Weatherability Improvers

Because of the intended outdoor applications of ASA materials, improved weatherability and color retention performance are of importance. These properties can be enhanced by additives. 

An attempt to improve the weatherability performance has been to increase pigmentation, particularly TiC 2. However, this additive contributes to the overall opacity, and therefore reflectivity and weatherability, of the resultant exterior siding. 

This method was disadvantageous because the light resistance of TiC 2 pigmentation over exposure to weathering seemed to be inadequate. 

Traditional ASA compositions and such with improved weatherability are shown in Table 12.6. The nylon 6,6 compounds are added as the color retention agent in place of the poly(ester)s of the conventional composition (30). 

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You might also like to add some herbs (see p.279) and edible flowers iseep.219). In cool climates, pots of fruiting vegetables such as tomatoes and peppers can be started off under cover (see p.226) and moved outside to a warm, sunny spot when the weather improves. 

Zinc oxide (ZnO) is widely used as an active filler in rubber and as a weatherability improver in polyolefins and polyesters. Titanium dioxide (TiOj) is widely used as a white pigment and as a weatherability improver in many polymers. Ground barites (BaS04) yield x-ray-opaque plastics with controlled densities. The addition of finely divided calcined alumina or silicon carbide produces abrasive composites. Zirconia, zirconium silicate, and iron oxide, which have specific gravities greater than 4.5, are used to produce plastics with controlled high densities. 

Other factors, like wind and rain, can affect the accuracy of the serves. Controlling factors like these is obviously beyond the researcher s power, but precautions were taken to avoid their influence. When, upon executing the experiments, the atmospheric conditions became adverse, our researcher retired to the comforts of the clubhouse, putting ofi" the runs until the weather improved. Each run consisted of a total of 100 serves. The number of successful serves in each run is given in the last column of Table 4.10. 

Uses Adhesion promoter, gloss aid, weatherability improver, water resist. aid, chem. resist, aid in primers, topcoats, floor paints, maintenance paints, label lacquers, and overprint varnishes resinous polyol in urethane and melamine-based coatings Properties Wh. pastilles sol. ( 25% solids) sol. in Arcosolv soivs., NMP, toluene insol. in water, ethylene and propylene glycols m.w. 3000 600 wt. avg.) sp.gr. 1.05 bulk dens. 5.006 Ib/qal acid no. < 0.1 hyd. no. 210 VOC 0.045%... 

Uses Monomer, flexibilizer, weatherability improver in powd. coatings, actylate/epoxy, vinyl ether/epoxy coating systems Features Low melting fast cure speed low coloration fast wet-out Properties Wh. solid, melts to colorless liq. 100-110 C melt vise. 15 cps (106 C) m.p. 100-110 C flash pt. (Pensky) 309 F Storage Store R.T. 

Features Good elec, insulator does not absorb water highly resist, to weathering improves rub resist., gloss inert to neariy all industrial chems. and solvs. 

Uses Monomer, flexibilizer, weatherability improver in powd. coatings, acrylate/epoxy, vinyl ether/epoxy coating systems Trade Names VEctomer VE 4230... 

Improved dimensional stability Improved heat resistance Improved processability Improved toughness Improved weatherability Improved solvent resistance Improved flame resistance Improved moisture resistance Improved esthetics and appearance, etc. 

On July 14, a Saturday, the plutonium was inserted into the bomb. Fat Man was then hoisted into place at the top of the tower. The scientists spent Sunday fretting over the weather as a storm had blown through that day. If the storm persisted, the test would be canceled out of fear that heavy winds would carry dangerous radiation miles away from the test site, endangering populated areas. Later Sunday the weather improved, and orders were given to explode the bomb at 5 30 a.m. on Monday. 

Uses Free-flow agent for fire extinguishers filler, thickener, reinforcing agent, weatherability improver for polysulfide sealants defoamer Features Hydrophobic... 

Outstanding properties increased stability to light weathering, improved chemical physical properties ... 

Improved Hot—Wet Properties. Acryhc fibers tend to lose modulus under hot—wet conditions. Knits and woven fabrics tend to lose their bulk and shape in dyeing and, to a more limited extent, in washing and drying cycles as well as in high humidity weather. Moisture lowers the glass-transition temperature T of acrylonitrile copolymers and, therefore, crimp is lost when the yam is exposed to conditions requited for dyeing and laundering. 

Uses. Neopentyl glycol is used extensively as a chemical intermediate in the manufacture of polyester resins (see Alkyd resins), polyurethane polyols (see Urethane polymers), synthetic lubricants, polymeric plasticizers (qv), and other polymers. It imparts a combination of desirable properties to properly formulated esterification products, including low color, good weathering and chemical resistance, and improved thermal and hydrolytic stabiUty. 

Pigments Aftertreatments. The surfaces of pigment particles can have different properties and composition than the particle centers. This disparity can be caused by the absorption of ions during wet milling, eg, the —OH groups, on the surface. In some cases, surfaces are modified intentionaHy to improve the pigments appHcation properties, interaction with the organic matrix, and weather resistance. 

Silicone resins with high phenyl contents may be used with medium or short oil alkyds as blends in air-dried or baked coatings to improve heat or weather resistance the alkyd component contributes to adhesion and flexibiUty. AppHcations include insulation varnishes, heat-resistant paints, and marine coatings. 

I ew Rubber-Modified Styrene Copolymers. Rubber modification of styrene copolymers other than HIPS and ABS has been useful for specialty purposes. Transparency has been achieved with the use of methyl methacrylate as a comonomer styrene—methyl methacrylate copolymers have been successfully modified with mbber. Improved weatherability is achieved by modifying SAN copolymers with saturated, aging-resistant elastomers (88). 

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