摘要:
A polymer precursor containing an oxazolin-2-one ring is made by reacting (a) an amino-reactive group containing compound having at least two groups capable of entering into an addition or condensation reaction with primary or secondary aromatically-bound amino groups with (b) an aromatic amine having at least one primary or secondary aromatically-bound amino group and at least one condensed oxazolin-2-one ring. The reactants are used in quantities such that for each aromatically bound primary or secondary amino group there are from 0.95 to 5 groups present in the amino-reactive group containing compound which are capable of reacting with the amino group. These polymer precursors may be used to produce high molecular weight polymers useful in the production of solid molded products, adhesives, foam plastics and coatings.
摘要:
The instant invention is directed to a process for the production of molded foams having a compact surface and cellular core and an integral density distribution over the cross-section of the body, comprising reacting(A) polyisocyanates, and(B) relatively high molecular and/or low molecular compounds having an average of at least two isocyanate-reactive hydrogen atoms in the presence of:(C) catalysts for the isocyanate polyaddition reaction and(D) blowing agents and optionally other known additives, in a closed mold under the conditions of foaming inside molds, the improvement wherein said polyisocyanates are aliphatic and/or alicyclic polyisocyanates and said catalysts are catalyst combinations of:(i) an alkali metal and/or alkaline earth metal hydroxide and(ii) a metal compound, the metal compound being the acetylacetonate of iron, C.sub.1 -C.sub.8 alcoholates, phenolates, enolates and/or acetylacetonates of metals of the 4th Main Group or sulfur compounds of metals of the 4th Main Group of the Periodic System of Elements in which the sulfur is directly attached to the metal atom.
摘要:
Polyurethane urea elastomers are produced by reacting polyisocyanates with compounds containing at least two isocyanate reactive hydrogen atoms having a molecular weight of 400 to 10,000 and mononuclear or dinuclear aromatic diamines. The aromatic diamines must have at least one sulfonamide group as a substituent on at least one of their aromatic rings. Known chain lengthening agents, activators, blowing agents, auxiliary agents and additives may also be included in the reaction mixture.Polyurethane elastomers produced by this process have excellent mechanical properties. In particular, such elastomers are soft yet have high tear propagation resistance.
摘要:
The invention relates to polyisocyanates corresponding to the following general formula: ##STR1## wherein X represents a radical of the type obtained by removing the more reactive isocyanate group from an organic diisocyanate containing isocyanate groups of different reactivity; andY represents a chlorine, bromine, C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.6 -C.sub.10 aryl, C.sub.6 -C.sub.10 aroxy radical or a radical corresponding to the general formula: --NH--CO--NH--X.These polyisocyanates are produced by reacting polyamines corresponding toX as shown above;Y represents --NH--CO--NH--X.
摘要:
The instant invention is directed to a process for the production of weather-resistant rigid molded foams based on polyurethanes having a dimensional stability under heat according to DIN 53 432 of at least 70.degree. C. and a compact surface, a cellular core and an integral density distribution throughout the cross-section of the moldings, comprising foaming a foamable reaction mixture of polyisocyanates, polyhydroxyl compounds, blowing agents and, optionally, other isocyanate-reactive compounds, activators and other auxiliaries in a closed mold under the conditions of in-mold foaming, the improvement wherein the polyisocyanates used are reaction products containing isocyanate groups and urethane groups, said reaction products formed by reacting diisocyanates containing at least one cycloaliphatically bound isocyanate group and no more than one aliphatically bound isocyanate group with sub-stoichiometric quantities of organic polyhydroxyl compounds.
摘要:
The instant invention is directed to a process for the production of a light fast, transparent polyurethane elastomer comprising reacting:(A) from 90 to 50% by weight, based on the polyurethane solids content, of a compound having a molecular weight of from 400 to 10,000 which has at least two Zerewitinoff active hydrogen atoms;(B) from 50 to 10% by weight, based on the polyurethane solids content, of an aliphatic and/or alicyclic polyisocyanate; and(C) from 0 to 20% by weight, based on the polyurethane solids content, of a chain-lengthening agent having a molecular weight of from 60 to 400; in the presence of:(D) catalysts for the isocyanate polyaddition reaction, the improvement wherein said catalysts, component (D), is a catalyst combination of:(a) an alkali metal hydroxide and/or alkaline earth metal hydroxide; and(b) an organometallic compound selected from the group consisting of the acetyl acetonate of iron, C.sub.1 -C.sub.8 alcoholates, phenolates, enolates and/or acetyl acetonates of metals of the 4th main group or sulfur-containing compounds of metals of the 4th main group, in which compounds the sulfur is directly attached to the metal atom.
摘要:
The invention relates to polyisocyanates corresponding to the following general formula: ##STR1## wherein X represents a radical of the type obtained by removing the more reactive isocyanate group from an organic diisocyanate containing isocyanate groups of different reactivity; andY represents a chlorine, bromine, C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.6 -C.sub.10 aryl, C.sub.6 -C.sub.10 aroxy radical or a radical corresponding to the general formula: --NH--CO--NH--X.
摘要:
The present invention relates to N,N'-bis-(4-isocyanatocyclohexyl)urea obtained from the reaction with water of cyclohexane-1,4-diisocyanate having a high trans isomer content. This invention further relates to the process for preparing the N,N'-bis(4-isocyanatocyclohexyl)urea and to its use in the synthesis of polyurethanes.
摘要:
This invention relates to a process for the production of polyurethanes, particularly polyurethane foam moldings having a compact skin and a cellular core, using special tin activators.
摘要:
This invention relates to new tetrahydropyrimidines, to a process for their production and to their use as catalysts in the production of polyurethane plastics, including polyurethane foams.