摘要:
The present invention is directed to a polyurethane system containing isocyanate groups prepared by reactingA) 70 to 98 parts by weight of at least one polyester diol having a melting point of 30.degree. C. to 60.degree. C. and a molecular weight of 800 to 8,000,B) 2 to 30 parts by weight of at least one polyester diol having a melting point of 65.degree. C. to 150.degree. C. and a molecular weight of 600 to 8,000, andC) no more than 1 mole of a diol having a molecular weight of less than 600 per moles of A) plus B), with,D) at least one organic polyisocyanate, the ratio of isocyanate groups to hydroxyl groups is between 3:1 and 1.2:1.
摘要:
The invention relates to a process for bonding surfaces with isocyanate-containing prepolymers having an isocyanate group content of less than 1.8% by weight, based on the prepolymer, and an average molecular weight MW.sub.n of at least 4,500 in which (a) the prepolymers are prepared by the reaction of (i) polyester diols prepared from dodecanedioic acid and even-numbered alkane diols containing at least 6 carbon atoms and (ii) diisocyanates; (b) the prepolymer is applied as a hotmelt adhesive at a temperature of 80 to 160.degree. C. by spin-spraying onto at least one surface to be bonded; and (c) the treated surface is brought into intimate contact with a second surface to be bonded.
摘要:
This invention relates to crystalline, isocyanate group-containign hot melt adhesives based onfrom 70-95% by weight of a prepolymer A based on polyester diols having a molecular weight of from 1500 to 10,000 and melting points of from 50.degree. to 90.degree. C. and diisocyanates in a ratio of isocyanate groups of the diisocyanate to the hydroxyl groups of the polyester diol of from 3:1 to 1.2:1 andfrom 5-30% by weight of a component B having a molecular weight of from 1000 to 10,000 based on polyesters having melting points of from 60.degree. to 150.degree. C., in which component B contains at most 0.5 Zerewitinow active groups per molecule.
摘要:
The present invention relates to solvent-free two-component polyurethane adhesive systems with high initial strengths and low levels of migration derived from a select reactants comprising a hydroxyl polyester and an isocyanate containing prepolymer.
摘要:
The present invention relates to aqueous polyurethane dispersions based onA) a relatively high molecular weight polyhydroxyl component containing carboxylic acid groups,B) optionally another relatively high molecular weight polyhydroxyl component which is substantially free of carboxylic acid groups,C) optionally low molecular weight polyhydroxyl compounds as chain lengthening agents,D) organic polyisocyanates andE) a neutralizing agent capable of converting the carboxylic acid groups into carboxylate groups,the dispersions are characterized in that the carboxyl group-containing relatively high molecular weight polyhydroxyl component A) is the esterification product of a polyether polyol a1) in the molecular weight range of from 400 to 5000, with a polycarboxylic acid a2); the dispersions are useful as laminating adhesives.
摘要:
Disclosed herein is a transparent adhesive containing isocyanate groups based on at least one polyol and at least one polyisocyanate, characterized in that the adhesive contains urea groups.
摘要:
Polyurethane elastomers with reduced gas permeability are prepared by reaction of: a) diisocyanates, b) compounds with a molecular weight of 500 to 10,000 having at least two hydrogen atoms that are reactive towards isocyanates, c) compounds with a molecular weight of 61 to 499 having at least two hydrogen atoms that are reactive towards isocyanates, and optionally d) further auxiliaries and additives, characterized in that i) the ratio of the isocyanate groups in a) to the sum of the isocyanate-reactive groups in b) and c) is between 1:0.80 and 1:1.05 (isocyanate:isocyanate-reactive), and ii) the compound b) contains 3 to 15% by wt. of amide bonds ##STR1##
摘要:
The invention relates to an improved process for the production of polyamines containing urethane and/or urea and/or biuret and/or isocyanurate groups and, preferably, also alkylene ether, carbonate and/or acetal groups by the alkaline hydrolysis of corresponding compounds containing terminal aliphatic and/or aromatic isocyanate groups.To this end, the compounds containing terminal NCO-groups, preferably NCO-preadducts, are converted by means of selected bases into the carbamates and neutralized by introduction into equivalent quantities of acid or by the simultaneous introduction of the components in equivalent quantities into a reaction vessel, after which the polyamines are directly isolated by methods known per se.The invention also relates to the use of the polyamines obtained by the process for the production of polyurethanes.
摘要:
The invention relates to moisture-curable adhesive or sealant compositions comprising a) prepolymers based on aliphatic polyisocyanates and having isocyanate contents of 2 to 20 wt. %, and b) bis(dimethylaminoethyl)ether as catalyst. The compositions exhibit good storability, processability can be adjusted within wide limits and also provide rapid through-hardening.
摘要:
The present invention relates to a process for bonding two or more wood substrates by using as the adhesive isocyanate-terminated prepolymers having an isocyanate content of 8 to 20 wt. % and containing the reaction product of a) at least one organic polyisocyanate with b) at least one organic polyhydroxyl compound containing the reaction products of i) organic polyisocyanates with ii) polyamines, hydrazines and/or hydrazides having primary and/or secondary amino groups dispersed in a iii) polyethers having at least two hydroxyl groups and a number average molecular weight of 500 to 12,000; and, the present invention also relates to the bonded substrates obtained by this process.