Water-repellent compound

Early waterproofing treatments consisted of coatings of a continuous layer impenetrable by water. Later water-repellent fabrics permitted air and moisture passage to improve the comfort of the wearer. Aluminum and zirconium salts of fatty acids, siUcone polymers, and perfluoro compounds are apphed to synthetic as well as natural fibers. An increase in the contact angle of water on the surface of the fiber results in an increase in water repeUency. Hydrophobic fibers exhibit higher contact angles than ceUulosics but may stiU require a finish (142). 

Water Repellency and Water Resistance. Water repeUency is defined as the abihty of a textile fiber, yam, or fabric to resist wetting, whereas water resistance is a general term appHed to a fabric s abiUty to resist wetting and penetration by water (2). A third term, waterproof, is appHed to those fabrics that do not allow any water penetration at all. Waterproof fabrics are generally coated with an impermeable surface layer that does not allow air permeabihty. Water-repellent finishes are hydrophobic compounds that are appHed to fabrics to inhibit water penetration while still allowing air permeabihty. 

Silicone fluids containing Si—H groups are also used for paper treatment. The paper is immersed in a solution or dilute emulsion of the polymer containing either a zinc salt or organo-tin compound. The paper is then air-dried and heated for two minutes at 80°C to cure the resin. The treated paper has a measure of water repellency and in addition some anti-adhesive properties. 

There are basically two types of collector molecules ionizing and nonionizing compounds. The former dissociates into ions in water, while the latter does not. Ionizing collectors are classified in accordance with the type of ion (anion or cation) that causes the water-repellent effect in water. 

There are reactive softeners, some of which are N-methylol derivatives of long-chain fatty amides (10.241) while others are triazinyl compounds (10.242). The N-methylol compounds require baking with a latent acid catalyst to effect reaction, whereas dichloro-triazines require mildly alkaline fixation conditions. The N-methylol compounds are sometimes useful for combination with crease-resist, durable-press, soil-release and water-repellent finishes. In this context, the feasibility of using silane monomers such as methyltri-ethoxysilane (10.243), vinyltriethoxysilane (10.244), vinyl triace tylsilane (10.245) and epoxypropyltrimethoxysilane (10.246) in crosslinking reactions to give crease-resist properties and softness simultaneously has been investigated [492]. 

Cook, M. A. and Nixon, J. C., 1950. Theory of water-repellent films on solids formed by adsorption fi-om aqueous solutions of heteropolar compounds. J. Phys. Colloid Chem., 54 445 - 459... 

This work describes the application to soil of compounds of a previous study (11) which dealt primarily with organic synthesis and physical properties of reaction products of pure fatty acids with BETA. In this study derivatives were prepared from various industrial fatty materials. In addition, water infiltration studies on sand, sandy soil, and clay soils were carried out on the previously prepared and new compounds. Finally, an investigation was initiated to determine the biological effects of one water-repelling chemical, the partially hydrogenated tallow-fatty acid-DETA reaction product, on seed germination and plant growth. 

Zirconyl chloride is used to make pigment toners and improve properties of color lakes of acid and basic dyes. Also, it is used to prepare body deodorants and antiperspirant, water repellant, dye precipitant, catalysts, and many zirconium compounds. 

Within recent years, chemists have developed a whole line of new silicon compounds called silicones. Some of them are oil-like. Some look like putty ( Silly Putty ). Still others are rubber-like. Paper and cloth can be made water-repellent by being treated with suitable silicones. 

Organopolysiloxanes are also used as ingredients of topical cosmetic formulations, because of their blandness and their capacity to impart water repellency and lubricity to treated surfaces. Compounds, used in this field of application, are mainly low molecular weight organopolysiloxanes. 

Many silicone compounds have water-repellent (waterproofing) properties. Usually materials are waterproofed with silicone oligomers with various reactive groups, which interact with the treated surface chemically or physically. Effective waterproofers are silicone oligomers with =Si-I I, =Si-OH or =Si-Ona groups. They differ in their chemical composition and application. 

The compound C8F17CH2CH20 Ti(0-/-C3H7)3 is useful in car polishes to impart water repellency (145). 

It may be somewhat surprising that the shorter fatty polar compounds effectively make the mercury water-repellent whereas the longer ones do not. The situation can be pictured, however, as one in which the relative affinities of bulk water and fatty monolayer for the mercury surface determines which substance displaced the other. Among the polar fatty compounds 7re, at any given temperature, can be taken as an index of affinity between the spread material and the mercury. On this basis the Ci2-Ci4 compounds in Table II have greater affinity for mercury... 

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