Leather liberating

Potassium forms corrosive potassium hydroxide and liberates explosive hydrogen gas upon reaction with water and moisture. Airborne potassium dusts or potassium combustion products attack mucous membranes and skin causing bums and skin cauterization. Inhalation and skin contact must be avoided. Safety goggles, full face shields, respirators, leather gloves, fire-resistant clothing, and a leather apron are considered minimum safety equipment. 

Chlorate. Sodium chlorate, chlorate of soda, [CAS 7775-09-9], NaC103. white solid, soluble, mp 260 C, powerful oxidizing agent and consequently a fire hazard with dry organic materials, such as clothes, and with sulfur upon heating oxygen is liberated and the residue is sodium chloride formed by electrolysis of sodium chloride solution under proper conditions. Used (1) as a weedkiller (above hazard), (2) in matches, and explosives, (3) in the textile and leather indusUies. 

Leather scrap may also be utflised for glue manufacture by digestion with an aqueous solution containing per cent, of sodium hydroxide on the weight of the dry leather scrap. The mixture is boiled until the gluc-ltke substances are liberated, d ned and filtered. 

USE Fusion of minerals to make them so] for analysis for liberating CO. in carbonic acid baths. Technical grades are used for pickling metals, carbonizing woo], bleaching and swelling leather, manuf magnesia cements, etc. 

Hydrofluoric acid attacks glass, concrete, and many metals (especially cast iron). It also attacks carbonaceous natural materials such as woody materials, animal products such as leather, and other natural materials used in the laboratory such as rubber. Reactions with carbonates, and sulfites and cyanide will produce asphyxiants or toxic gases. Lead, platinum, wax, polyethylene, polypropylene, polymethylpentane, and Teflon will resist the corrosive action of the acid. In contact with metals with which it will react, hydrogen gas is liberated and hence the danger exists of a spark or flame resulting in an explosion in areas where this may occur. 

Polyvinyl chloride is one of the cheapest plastics in use today. It is prepared by the polymerization of vinyl chloride (VCM) (CH2=CHC1, B.P.—14°C) as a suspension or emulsion in a pressure reactor. The polymer is unstable at high temperamres and liberates HCl at T > 200°C. It can be injection molded or formed into a hard and brittle material. It can be readily softened by the addition of plasticizers such as diethylhexylphthalate to the extent of 30%. Plasticized PVC is used as an upholstery substitute for leather. Since the plasticizer is volatile to a small extent, it slowly leaves the vinyl which eventually becomes hard, brittle, and then cracks. This can be restored by replacing the plasticizer by repeated conditioning of the vinyl surface. 

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