| 摘要 |
<p>1,221,639. Aqueous size. PPG INDUSTRIES Inc. 2 May, 1969 [3 May, 1968], No. 22406/69. Headings C3B and C3R. [Also in Division D1] An aqueous size suitable for application to glass fibre strands during their formation comprises an aqueous emulsion of a curable, blocked, polyurethane prepolymer, a curing agent for the prepolymer and an amino silane. The size suitably comprises 3 to 9% by weight of the blocked prepolymer and 0À2 to 1% by weight of the amino silane and may contain a non-reactive organic solvent. Preferably, the prepolymer is prepared by reacting excess of a polyisocyanate with a polyhydroxy compound, e.g. a polyether or polyester and is blocked by reaction with caprolactam. The curing agent may be more of the polyether or polyester used to form the prepolymer or a polyamine. Exemplified amino-silanes are amino-alkyl alkoxy silanes, e.g. gamma aminopropyl triethoxysilane. The size may be stabilized by adding thereto an alkoxylated amine or amide reacted with a polycarboxylic acid and then reacted with an epoxide compound. Such a compound may be one prepared by reacting 1 mole of an ethoxylated stearyl amine with 2 moles of phthalic anhydride followed by reaction of the product with an epoxy resin. A lubricant such as the pelargonic acid amide of tetraethylene pentamine may also be added to the size. The size may be applied to individual glass fibres or their emergence from an orifice in a bushing, suitably before they are grouped together to form a strand. The strand may be heat treated to remove the solvent and water and to split off the blocking agent so that the polyurethane cures. The sized strands may be chopped and blended in a tumbler mill with particles of a polyamide resin and the mixture injection moulded to form a reinforced polyamide.</p> |
