摘要:
Water-emulsifiable polyisocyanates containing a) aliphatic, cycloaliphatic and aromatic polyisocyanates and b) reaction products of the abovementioned polyisocyanates with polyvinylpyrrolidones which have at least one group which is reactive with isocyanate.
摘要:
Aqueous dispersions of polyurethanes which are crosslinkable by the action of high energy radiation contain (a) a polyisocyanate, (b) a polyol having a molecular weight of from 400 to 6,000 g/mol, (c) if required, a polyol having a molecular weight of from 62 to 399 g/mol, (d) if required, a polyamine having two or more amino groups which are reactive to isocyanate, (e) if required, an aminoalcohol having one or more amino groups which are reactive to isocyanate, (f) a compound containing ionic groups or groups which can be converted into ionic groups and one or more hydroxyl or amino groups which are reactive to isocyanate (g) if required, a monofunctional polyetheral and (h) a compound having one or more ethylenically unsaturated groups and one or more hydroxyl groups. The compound having an ethylenically unsaturated group (h) is used in amounts corresponding to 0.02-0.08 gram equivalent, based on the polyisocyanate (a), of OH, and the polyurethane, dissolved in dimethylformamide, has a Fikentscher K value greater than 40 or is insoluble in dimethylformamide.
摘要:
The present invention relates to new emulsion polymers, to processes for preparing them, and to their use in coating material for the purpose of improving the water resistance.
摘要:
The invention relates to a hydraulic drive, especially for two-cylinder thick matter pumps. Said hydraulic drive comprises at least one main pump (10) embodied as a hydraulic variable displacement pump, and two hydraulically actuatable drive cylinders (20,22) that are each connected to a connection line (16,18) of the main pump (10) by means of pump connections mounted on one end thereof, forming a closed hydraulic circuit, and communicate with each other at the ends thereof opposing the pump connections (24,26) by means of a swinging oil line (28). The hydraulic drive also comprises a feed pump (42), by which means pressurized oil is fed from an oil tank to the current low-pressure side into the hydraulic circuit, and a flushing branch (52), by which means a flushing oil flow is branched off from the current low-pressure side under a limited pressure into the oil tank (44). In order to avoid low-pressure influxes during the reversal process of the main pump (10), the flushing oil flow is blocked and then released in a time-delayed manner during each reversal process of the main pump (10), independently of the differential pressure in the connection lines.
摘要:
Isocyanato compounds with capped, isocyanate-reactive groups are those of the formula I ##STR1## where R.sup.1 and R.sup.2 are hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.10 -aryl or C.sub.7 -C.sub.10 -aralkyl or together form C.sub.3 -C.sub.10 -alkanediyl,X and Y are --O--, --S-- or ##STR2## where R.sup.4 is hydrogen, C.sub.1 -C.sub.20 -alkyl which is uninterrupted or interrupted by oxygen atoms in ether function, or is C.sub.6 -C.sub.10 -aryl or C.sub.7 -C.sub.10 -aralkyl,R.sup.3 is C.sub.1 -C.sub.10 -alkanediyl which together with --X--CR.sup.1 R.sup.2 --Y-- forms a 4-7-membered ring,in which either one hydrogen in R.sup.3 or the radical R.sup.4 in ##STR3## is replaced by an allophanate group R.sup.Ia ##STR4## in which R.sup.5 is a divalent aliphatic, alicyclic, araliphatic or aromatic C.sub.2 -C.sub.20 hydrocarbon unit,R.sup.6 is a single bond or a divalent aliphatic, alicyclic, araliphatic or aromatic C.sub.1 -C.sub.20 hydrocarbon unit or a mono- or poly(C.sub.2 -C.sub.4 -alkylene oxide) unit, andR.sup.7 is a carbamoyl radical ##STR5## or a biuret group R.sup.Ib ##STR6## in which one R.sup.8 is hydrogen and the other is as defined for R.sup.7 or a biuret group R.sup.Ic ##STR7## in which one R.sup.9 is as defined for R.sup.7 and the other is as defined for R.sup.1or a thioallophanate group R.sup.Id ##STR8##
摘要:
The invention is to a process for the preparation of biuret-containing polyisocyanates by catalytic reaction of aliphatic and/or cycloaliphatic diisocyanates with a biuretizing agent, where the biuretizing agent employed is water in finely disperse form and the reaction is carried out in the presence of OH-acidic compounds.
摘要:
The invention provides a composition for producing surface coatings combining improved hardness, scratch resistance and acid resistance with good reflow behavior, a process for preparing such a surface coating, and for the use of polyisocyanatoisocyanurates having a functionality of more than 3.5 and a viscosity at 23° C. of more than 3500 to produce surface coatings.
摘要:
Sheet-like polyurethane moldings are produced by impregnation of porous sheets with a prepolymer containing free isocyanate groups and reversibly blocked isocyanate-reactive groups or containing free isocyanate-reactive groups and reversibly blocked isocyanate groups, and subsequent reaction of the prepolymers in a heated mold.
摘要:
In one-component and two-component polyurethane coating compositions comprising at least one reactive component capable of reacting with polyisocyanates, the reactive component is a compound A) containing an isocyanate group, a urethane, thiourethane or urea group and two capped isocyanate-reactive groups.