Abstract: The present invention relates to a crosslinkable polyester/isocyanate composition suitable for preparing composite manufactured articles endowed with high structural mechanical properties, by means of injection processes, comprising:A--a polyfunctional isocyanate;B--an unsaturated polyester resin, or a vinyl ester resin, or a mixture of both said resins, wherein said resin can contain free hydroxy groups;C--a free-radical polymerization initiator;D--a promoter of decomposition of (C) initiator;E--a catalyst of (A) isocyanate trimerization.

Abstract: This invention relates to crosslinkable polymeric compositions and a process for preparing them which show a low content of vinyl monomers, are suitable for the fabrication of composite materials, have good mechanical properties, and comprise: a liquid polyisocyanate; a polyol having a maximum functionality of 7 and an average molecular weight of from about 200 to about 10,000; an unsaturated polyester or a vinylester resin; a radical polymerization initiator stable at temperatures below 70.degree. C.; a decomposition promoter for the initiator; a trimerization catalyst for the isocyanate; and optionally, a mineral filler having dehydrating properties.

Abstract: A thermoplastic polyurethane endowed with improved heat distortion resistance, which comprises the product of reaction ofat least one polyisocyanate, preferably an organic diisocyanate;at least one polyol material reactive with the isocyanate and having a molecular weight higher than 400;a chain extender having a molecular weight lower than 400; andan aromatic anhydride having the formula (I): ##STR1## wherein A is a possibly substituted (C.sub.6 -C.sub.30) aromatic radical, m may be 0 or an integer from 1 to 3, and n is an integer equal to 1 or 2.

Abstract: The invention concerns a process for the manufacture of thermoplastic polyurethanes wherein an organic polyisocyanate is made to polymerize with a polyol (reactive with same isocyanate) in the presence of a chain extending agent having a molecular weight lower than 400, under continuous stirring, at a temperature higher than 150.degree. C. and for a time sufficient to obtain a product having a melt flow index lower than 25 g/10'.

Abstract: Two-component fibers, having surface area of at least 1 m.sup.2 /g, suited for replacing cellulose fibers in the manufacture of paper and paper-like products comprise a core of olefinic polymer and from 2 to 50% by weight of a sheath of a hydrophilic polymer, and exhibit values of the tenacity higher than 3,000 meters and cohesion higher than 300 meters. They are prepared by extruding a stable emulsion formed by a mixture of a solution of the olefinic polymer with a solution of the hydrophilic polymer in reciprocally immiscible solvents, at a temperature exceeding the boiling temperature of the solvent of the olefinic polymer and at least equal to the dissolution temperature of such polymer in such solvent, in a medium at a lower pressure, by using a volume ratio of solvent for the olefinic polymer to solvent for the hydrophilic polymer of at least 2.5 and concentrations of hydrophilic polymer in its solution of at least 2 g/l of solvent.

Abstract: Moisture-resistant packing cardboard of the corrugated type is prepared from flat paper sheets formed from 10% to 90% by weight of cellulose fibers and from 90% to 10% by weight of fibrils of at least one thermoplastic polymer and having a surface area greater than 1.0 m.sup.2 /gm, by heating the sheets under pressure on an undulated surface and coupling the resulting corrugated or undulated sheets with one or more flat sheets to which the corrugated sheet is adhered through the tips of the corrugations or undulations.

Abstract: A process for obtaining water-dispersable polyolefin fibers endowed with a high degree of cohesion consists in maintaining the fibers in contact with a stable emulsion formed by a water solution of polyvinyl alcohol and a poor solvent for the polyolefin, under stirring in turbulence conditions, at a temperature lower than the boiling temperature of the emulsion.

Abstract: Composite sheets comprising a layer of cellulosic fibers and a layer adjacent thereto consisting in whole or in part of thermoplastic fibers are made to adhere by superimposing the sheets on the side of the cellulosic fibers layer and by inserting between such layers a film of a thermoplastic polymer having:(a) a melting temperature lower than the melting temperature of the polymer forming the thermoplastic synthetic fibres contained in the layer adjacent to the cellulosic layer, intended for the adhesion, of the composite sheet;(b) a viscosity in the molten state--measured in a capillary viscosimeter, at a velocity gradient equal to or lower than 10.sup.-1 seconds, and at a temperature comprised between a temperature higher by 10.degree. C. than the melting temperature of such polymer and a temperature higher by 20.degree. C. than the melting temperature of the abovesaid thermoplastic fibres--lower than 1.multidot.10.sup.8 poises, and preferably lower than 1.multidot.10.sup.

Abstract: Polymeric articles filled with glass fibers are prepared by methods used in paper making, starting from aqueous dispersions of glass fibers with polyolefinic fibrils having a high surface area, by deposition in sheets, drying and pressure-molding, optionally after bonding the sheets in a sandwich-like manner with an intermediate thermoplastic polymeric plate, not containing glass fibers, and having a modulus of flexure lower than that of the glass fibers contained in such sheets, so as to thermoweld said plate to the sheets.

Abstract: Disclosed are reverse osmosis anisotropic gel-type membranes having the structure: ##STR1## WHEREIN N IS A WHOLE NUMBER; A is a divalent group derived from piperazine and having the structure: ##STR2## WHEREIN X IS 0 TO 8 AND R is an alkyl group, and Q is at least two divalent organic groups selected from the group consisting of: ##STR3## wherein Y is O or S, ##STR4## Also disclosed are processes for preparing such membranes.

Abstract: Polymeric piperazinamides suitable for use in reverse osmosis membranes. These polymeric piperazineamides consist essentially of the repeating unit ##STR1## wherein x is zero or a whole number from 1 to 8, R is a substituent such as alkyl, and --A-- is a bivalent radical, namely an organic dicarbonyl radical which either is always of the formula ##STR2## wherein X is oxygen or sulfur, and R' and R" are each hydrogen, alkyl, or aryl, or else where some of said radicals --A-- are of formula (III) and the remainder of said radicals --A-- are organic dicarbonyl radicals differing from said formula (III).