Humidity resistance

Polyquatemium-4 is the copolymer of hydroxyethjdceUulose and diallydimethyl ammonium chloride. It provides a firmer hold than polyquatemium-11 and has better humidity resistance. 

Natural Gums. These were used in early styling products, formerly called wave sets. Natural gums generally make hazy solutions and the dried film tends to flake. For these reasons they are rarely used. Some of these gums, eg, tragacanth and alginates, can create humidity-resistant films and have limited use for specific product concepts. 

Vinyl acetate (VA)/crotonates copolymer became available in the late 1950s. It was the first polymer used in fixatives to contain carboxyHc acid groups which, depending on neutralization percent, could produce variations in film properties eg, stiffness, humidity resistance, resiUency, tack, and removabihty by shampoo. It has largely been replaced in hair sprays by newer polymers. 

Chemical treatments commonly appHed to cormgated paperboard packaging materials include additives that impart various degrees of water resistance, humidity resistance, oil and grease resistance, product abrasion resistance, product corrosion resistance, adhesion release properties, flame-retardant properties, nonskid properties, and static electricity control properties to the finished package (1,2). 

The web materials used to form dmms and cans can be customized to each packaging apphcation. The materials are selected based on the package properties of moisture and humidity resistance, nonstick resistance, or barrier properties required. The adhesives used to bond the phes together include sihcates, poly(vinyl alcohol), and poly(vinyl acetate) (10). Sihcate adhesives are most commonly used in the manufacture of dmm packages. 

The properties of the polyurethane moulding compositions are also very similar to nylon 66. The greatest difference in properties is in water absorption, the 6,4-polyurethane absorbing only about of that of nylon 66 under comparable conditions. This results in better dimensional stability and a good retention of electrical insulation properties in conditions of high humidity. Resistance to sulphuric acid is somewhat bettter than with nylon 66 but both types of polymer are dissolved by phenols and formic acid. 

Diallyl Phthalate (DAP, DAIP) Powder Excellent humidity resistance. Withstands temperatures over 400 F. Easily processed. Dimensional stability excellent. May be compression, transfer and injection molded. Low cost. Precision potentiometers, RF connectors, waveguide auxiliaries, attenuators, heating panels, heated battery cases. 

The emulsifier aminomethyl propanol serves several purposes in hairspray. It acts as a buffering agent, controlling the acidity of the mixture to make it neutral ( pH balanced ). It also helps keep the polymers mixed with the water and alcohol, and controls the water solubility of the final mist, giving it the needed humidity resistance. It also helps to form the polymers into a gel. 

On zinc phosphate conversion coatings, the "Mannich" derivatives of poly-4-vinylphenol have demonstrated performance equivalent to chromic chromate systems in salt spray, humidity, and physical testing. In addition. Table III illustrates results observed with automotive body paint systems evaluated by the "scab" or "cycle" test which causes failure more typical of actual end use conditions than do salt spray evaluations. Again, results equivalent to chromic-chromate post-treatments were obtained. In addition, the humidity resistance and adhesion tests were essentially equivalent to the chromium controls. 

Altieri, P. A. Tessler, M. M. (1996). Water Humidity Resistant Starch Foams, U.S. Patent 5,554,660. 

Provision of corrosion and humidity resistance on metal products... 

The moisture barrier properties and humidity resistance make COCs suitable for container and film applications. The low moisture absorption prevents swelling. 

Evaluation of salt fog (ASTM B-117) and humidity resistance (ASTM D-2247) after 300 h of exposure was conducted on scribed panels of cold rolled steel (CRS), phosphatized steel, oily CRS, and aluminum. In accordance with test protocols, performance was rated from 2 to 10,2 representing the most extensive rusting and largest blisters and 10 representing the absence of any rust or blisters. Additionally, the frequency of the blisters was assessed by indicating dense (D), medium (M), or few (F). 

Standard tests of water immersion, humidity resistance, corrosion, flexibility, adhesion, and weight are conducted on other specimens of the same coating system. 

Similar to epoxy novolac resins, tetraglycidyl ether of tetraphenolethane resin is usually employed in a blend with lower-MW liquid resins. The high aromatic ring content combined with polyfunctionality provides increased thermal stability for high-temperature applications. The chemical resistance and humidity resistance of cured tetraglycidyl ether of tetraphenolethane epoxy resins are also outstanding. 

Tetraglycidyl ether of tetraphenolethane is an epoxy resin that is noted for high-temperature and high-humidity resistance. It has a functionality of 3.5 and thus exhibits a very dense crosslink structure. It is useful in the preparation of high-temperature adhesives. The resin is commercially available as a solid (e.g., EPON Resin 1031, Resolution Performance Polymers). It can be crosslinked with an aromatic amine or a catalytic curing agent to induce epoxy-to-epoxy homopolymerization. High temperatures are required for these reactions to occur. 

Because PVP has substantial humectant properties (and thus tends to absorb moisture in high humidity, causing the applied gel to become very sticky), alcohols (e.g., SD alcohol 40, ethanol, sorbitol) can be added to alleviate this problem. The addition of more humidity-resistant copolymers of PVP, such as vinyl acetate copolymer, allows the product to have increased resistance to moisture absorption. However, curl-activating gel products function by actually attracting moisture to the hair with the use of humectant polyols such as dimethylene copolyol. 

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