Abstract:
Water-based stains comprise or consist essentially of a polysaccharide resin and a crosslinking agent such as an isocyanate. Upon evaporation of water, the polysaccharide undergoes crosslinking with the isocyanate component, developing water resistance so that it will not redissolve upon application of a water-based or oil-based clearcoat; as a result, lifting is minimized after a drying time of, e.g., two to six hours.
Abstract:
This invention relates to a method of preparing a microcellular polyurethane elastomer by reacting naphthalene diisocyanate with a polyol to prepare a prepolymer containing an isocyanate (NCO) group, followed by mixing the prepared polyurethane prepolymer with a plasticizer, water, an emulsifier and the like, and then foaming the prepolymer blend to prepare a polyurethane elastomer, wherein the emulsifier is a mixture of (a) a compound selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,4′-cyclohexane diisocyanate and mixtures thereof, and (b) a C2-10 hydrocarbon having a molecular weight of 500 or less with two to four hydroxyl groups, or mixtures thereof. The method of the invention can optimize the viscosity and properties of the prepolymer resulting from the reaction of naphthalene diisocyanate with a polyol, thus improving processability.
Abstract:
The invention relates to a method for the continuous production of stable prepolymers based on high-melting diisocyanates, in particular, 1,5-naphthalindiisocyanate, and to the use thereof for producing polyurethane elastomers, in particular casting elastomers.
Abstract:
Stable NCO prepolymers are produced from polyisocyanates having a melting point greater than 70° C., preferably, naphthalene diisocyanate, having advantageous physical properties. An important feature of the process of the present invention is the rapid cooling of the prepolymer. The process of the present invention may be carried out on a continuous or batch basis. The prepolymers of the present invention are particularly suitable for the production of cast polyurethane elastomers.
Abstract:
Cellular polyisocyanate polyadducts are prepared by reacting (a) isocyanates with (b) compounds reactive toward isocyanates and (d) water, by a process in which a polyester having 2 hydroxyl groups and based on the condensation of at least one dicarboxylic acid with at least one alkanediol and/or alkenediol of 3 to 6 carbon atoms, whose carbon skeleton has at least one alkyl and/or alkenyl side chain between the hydroxyl groups, is used as (b).
Abstract:
The polyester polyols according to the invention with an average equivalent weight in the range from 200 to 4,000, which were prepared by reacting null,null-dicarboxylic acids with butane 1,4-diol, hexane 1,6-diol, propane 1,3-diol or pentane 1,5-diol and with polyols having 3 to 6 hydroxyl groups, are used for the preparation of PUR pourable elastomers with improved resistance to hydrolysis.
Abstract:
Polyurethanes are recycled by comminution to particle sizes of from 0.01 to 2 mm and addition to the polyaddition mixture for preparing polyurethanes from(a) polyisocyanates,(b) substances reactive toward isocyanates and having active hydrogens, and, if desired,(c) chain extenders and/or crosslinkers, catalysts, blowing agents and customary additivesin an amount of from 0.1 to 40% by weight, based on the poly-addition mixture.