摘要:
This invention relates to a new process for the production of polyisocyanates having a biuret structure by reacting aliphatic or cycloaliphatic diisocyanates with sub-stoichiometric quantities of specified aldoximes. When aldoximes are used as the biuretizing agents insoluble ureas are not formed during the reaction and nitriles which are easy to handle and distill are formed as secondary products.
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:
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:
This invention relates to a process for the production of non-cellular polyurethane ureas elastomers using a chain-extender mixture produced from asymmetrically alkyl-substituted anilines by condensation with formaldehyde. The chain-extending agents used in the instant invention show medium reactivity to compounds containing isocyanate groups. These chain-extending agents may be processed both in high-pressure and in low-pressure metering and mixing units because they are either liquid at room temperature or can be melted at relatively low temperatures (below 55.degree. C.). The homogeneous, i.e. non-cellular, polyurethane urea elastomers obtained in the instant invention are distinguished by having excellent mechanical properties.
摘要:
This invention relates to mixtures of polyols which are liquid at room temperature with functional aldoximes as blowing agents, wherein the aldoxime groups react with polyisocyanates to liberate carbon dioxide and are simultaneously incorporated by means of the functional group thereof into the polyurethane formed. The present invention also relates to a process for the production of polyurethane foams using these incorporated reactive blowing agents as the primary blowing agent in combination with blowing agents known in polyurethane chemistry. The process according to the invention described herein is suitable for the production of various polyurethane foams or cellular polyurethane elastomers, particularly including the production of semi-rigid and rigid polyurethane integral skin foams which are obtained by foaming the reaction mixture in closed molds.
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:
The present invention relates to an aqueous two-component coating composition wherein the binder contains(a) a component which is dissolved and/or dispersed in water, has an average hydroxyl number of 15 to 200 mg KOH/g, and contains(a1) a polyol component having a content of 8 to 450 milliequivalents, per 100 g of component (a1) solids, of chemically incorporated ammonium groups, .dbd.N.dbd..sup.+, comprising one or more polyaddition resins which are water-dilutable, contain hydroxyl groups, and have a molecular weight (M.sub.n) of 500 to 20,000 and(a2) up to 10 wt %, based on the weight of component (a1), of one or more reactive diluents which are water-soluble, have a molecular weight (M.sub.n) below 500, and contain at least one isocyanate-reactive group, and(b) a polyisocyanate component having an NCO content of 5 to 25 wt % comprising one or more polyisocyanates which are emulsified in the aqueous solution and/or dispersion of hydroxyl group-containing component (a),wherein components (a) and (b) are present in an amount sufficient to provide an equivalent ratio of isocyanate groups of component (b) to isocyanate-reactive groups of component (a) of 0.5:1 to 5:1.The present invention also relates to a process for the production of this coating composition and to their use for the production of coatings on water-resistant substrates.
摘要:
The present invention relates to a process for the preparation of polyurethanes suitable for use as thickeners for aqueous compositions by reacting at an NCO/OH equivalent ratio of 0.9:1 to 1.2:1a) a polyether component having an OH number of 10 to 30 mg KOH/g and obtained by the alkoxylation of a mixture ofa1) 30 to 80 mole % of a monofunctional alcohol or alkylphenol having 8 to 30 carbon atoms,a2) 2 to 10 mole % of sodium hydroxide or potassium hydroxide,a3) 10 to 60 mole % of water anda4) 0 to 10 mole % of a trihydric to hexahydric alcohol having a molecular weight of 92 to 600, with ethylene oxide or a mixture of ethylene oxide with up to 20 mole %, based on the total moles of alkylene oxides, of propylene oxide, in which the percentages of a1) to a4) add up to 100,withb) a polyisocyanate component containing at least one organic diisocyanate, optionally in admixture with up to 20 mole %, based on the total moles of component b), of higher than difunctional polyisocyanates.The invention also relates to the polyurethanes obtainable by this method and their use, optionally in combination with other thickeners, for the thickening of aqueous systems.
摘要:
The present invention relates to a process for the preparation of a coating composition bya) treating moisture-containing auxiliaries and additives at 60.degree. to 120.degree. C. with urethane group-containing isocyanates having (cyclo)aliphatically bound isocyanate groups, an (average) NCO functionality of 0.8 to less than 2.0 and an NCO content of 5 to 17% by weight andb) after completion of the isocyanate/water reaction, combining the mixture obtained in step a) with iscyanate prepolymers having (cyclo)aliphatically bound isocyanate groups.The present invention also relates to the coating composition obtained by this process and to a composition containing urethane group-containing isocyanates having (cyclo)aliphatically bound isocyanate groups, an (average) NCO functionality of 0.8 to less than 2.0 and an NCO content of 5 to 17% by weight and moisture-containing auxiliaries or additives.
摘要:
Aqueous lacquers, which contain grafted polybutadiene/maleic acid semi-esters or semi-amides as bonding agent, can be siccativated while the siccative is firstly dispersed in the aqueous phase and the bonding agent is dispersed in this dispersion.