A multifilament yarn of an aromatic polyamide, in particular poly-p-phenylene terephthalamide, having a tenacity of at least 15 cN/dtex and an initial modulus of at least 400 cN/dtex is provided with a water-soluble size, the filaments of the yarn having a cohesion corresponding to a Manra number not higher than 40. The yarn is made by subjecting a non-sized yarn having a moisture content which is lower than its equilibrium moisture content, while under a tension of at most 0.25 cN/dtex, to a continuous wetting treatment with an aqueous solution of a size and subsequently winding the treated yarn into a yarn package. The yarn package contains a single continuous length of the sized yarn. The sized yarn is suitable as warp and weft yarn in the weaving industry.
A multifilament yarn of an aromatic polyamide, in particular poly-p-phenylene terephthalamide, is provided with an adhesive coating of a cured epoxy compound, the yarn having a free epoxide content not higher than 10 mmoles/kg. The yarn is made by spinning a solution of an aromatic polyamide into a coagulation bath and subjecting the resulting filaments to the subsequent steps of washing, applying a curable epoxy compound and one or more alkaline curing agents, curing and winding the yarn thus treated into a package. The resulting yarn can be processed into a reinforcing element for, e.g., tires in a one-step dipping process. A cord made from the yarn displays an improved resorcinol-formaldehyde-latex dip pickup.
Surface frictional characteristics of a wholly aromatic polyamide fiber are desirably modified by applying to the fiber at least 0.05% by weight, based on the fiber, of a reaction product of a polyoxyethylene adduct of glyceride having at least one hydroxyl group in the molecule with a dibasic acid and/or a dibasic anhydride. Preferably, prior to the application of the reaction product, at least 0.01% by weight of an inorganic compound powder is applied to the fiber.
A multifilament yarn of an aromatic polyamide, in particular poly-p-phenylene terephthalamide, is provided with an adhesive coating of a cured epoxy compound, the yarn having a free epoxide content not higher than 10 mmoles/kg. The yarn is made by spinning a solution of an aromatic polyamide into a coagulation bath and subjecting the resulting filaments to the subsequent steps of washing, applying a curable epoxy compound and one or more alkaline curing agents, curing and winding the yarn thus treated into a package. The resulting yarn can be processed into a reinforcing element for, e.g., tires in a one-step dipping process. A cord made from the yarn displays an improved resorcinol-formaldehyde-latex dip pickup.
Low viscosity, fast curing binders for nonwoven cellulosic materials comprise an aqueous dispersion of discrete particles of a highly functionalized emulsion copolymer resulting from the copolymerization of a water insoluble olefinic non-ionic organic compound, a water soluble olefinic carboxylate compound and a water soluble olefinic hydroxy ester or a water soluble olefinic amide or a mixture of hydroxy ester and amide. The emulsion copolymer dispersion is admixed with a latex to provide a binder having a relatively low viscosity and capable of reaching about 80 percent of fully cured wet tensile strength in 8 seconds or less.
Copolymers suitable for use as temporary surface protection for two- or three-dimensional structures and as sizing agents are based on C.sub.1 -C.sub.8 -alkyl acrylates and/or methacrylates and are obtainable by free radical emulsion or solution polymerization of A) from 50 to 95% by weight of a C.sub.1 -C.sub.8 -alkyl acrylate or methacrylate, B) from 5 to 20% by weight of an unsaturated carboxylic acid or anhydride, C) from 0 to 20% by weight of further water-soluble comonomer, and D) from 0 to 10% by weight of other comonomer in the presence of E) from 2 to 60 parts by weight of a polyvinyl alcohol per 100 parts by weight of the monomer mixture of A) to D).
