Bonding process

摘要

Cyclic acetals are obtained by condensing chloral or its hydrate with di- or polyhydric alcohols. Side-chains if present may then be oxidized or esterified or both. In the examples: (1) glycerol is condensed with chloral; (2) propylene glycol is condensed with chloral hydrate; (3) pentaerythritol is condensed with chloral, both monocyclic and dicyclic acetals are obtained; (4) trimethylolpropane is condensed with chloral hydrate; (5) ethylene glycol is condensed with chloral; (6) trichlorethylidene-glycerol is refluxed with thionyl chloride to yield 2 - trichloromethyl - 4 - chloromethyl - 1,3 - dioxolane; (7) 2-trichloromethyl-5,5-bis-hydroxymethyl-1,3-dioxane is esterified by treatment with acetic anhydride and sodium acetate; (8) trichlorethylidene-glycerol is similarly acetylated to trichlorethylidene-glyceryl acetate; (9) trichlorethylidene-glycerol is esterified with trichloracetyl chloride in pyridine; (10) trichlorethylidene-glycerol is oxidized with alkaline potassium permanganate to yield 2-trichloromethyl-4-carboxy-1,3-dioxolane; (11) trichlorethylidene-glycerol is oxidized with concentrated nitric acid and the product reacted with the addition compound of boron trifluoride and methanol to yield 2-trichloromethyl-4-carbomethoxy-1,3-dioxolane; (12) trichlorethylideneglycerol is reacted with phthalic anhydride in pyridine to yield mono-trichlorethylidene-glyceryl phthalate; and (13) the corresponding half-ester of succinic acid is made similarly.ALSO:Polyester fibres are bonded by contacting at least part of the outer surface of a mass of the fibres with a cyclic acetal containing in its molecule the grouping: where n = 0 or 1. These acetals may be obtained by condensing chloral or its hydrate with suitable di- or polyhydric alcohols. If the alcohol has three or more hydroxyl groups, those not acetalized may be chlorinated, esterified or oxidized to carboxylic acids, which may then be esterified. The acetal may be applied by steeping the mass of fibres in the liquid acetal, or by spraying the acetal on to part or all of the surface of the mass of fibres, and if desired into some or all of the interstices between the fibres. An elevated temperature is preferably used. The product is useful for packing, filling or thermal or electrical insulation.