摘要:
A process for the preparation of homogeneous and cellular polyurethane plastics by the reaction of(a) organic polyisocyanates;(b) compounds containing at least 2 Zerewitinoff-active hydrogen atoms and having molecular weights of from 400 to 10,000;(c) chain extenders, and, optionally, additional(d) short-chained compounds containing at least 2 Zerewitinoff-active hydrogen atoms and having a molar mass of from 32 to 400, as well as, optionally,(e) catalysts, blowing agents and other known additives,is described, which is characterized in that 1,4-3,6-dianhydro-hexites, preferably 1,4-3,6-dianhydro-D-sorbitol and/or 1,4-3,6-dianhydro-D-mannitol, optionally mixed with lower molecular weight compounds, preferably with polyols having a molecular weight of from 62 to 400, particularly preferably butane diol-1,4 are used as the chain extenders. The new chain extenders produce high quality elastomers and foams.
摘要:
A process for the preparation of homogeneous and cellular polyurethane plastics by the reaction of(a) organic polyisocyanates;(b) compounds containing at least 2 Zerewitinoff-active hydrogen atoms and having molecular weights of from 400 to 10,000;(c) chain extenders, and, optionally, additional(d) short-chained compounds containing at least 2 Zerewitinoff-active hydrogen atoms and having a molar mass of from 32 to 400, as well as, optionally,(e) catalysts, blowing agents and other known additives,is described, which is characterized in that 1,4-3,6-dianhydro-hexites, preferably 1,4-3,6-dianhydro-D-sorbitol and/or 1,4-3,6-dianhydro-D-mannitol, optionally mixed with lower molecular weight compounds, preferably with polyols having a molecular weight of from 62 to 400, particularly preferably butane diol-1,4 are used as the chain extenders. The new chain extenders produce high quality elastomers and foams.
摘要:
Polyurethane elastomers are made by reacting organic polyisocyanates with compounds having at least two groups containing isocyanate-reactive hydrogen atoms and a molecular weight of from 400 to 10,000 and a 1,4-monoanhydro-tetritol in accordance with techniques known to those in the art. Known chain-lengthening agents, auxiliaries and additives may be included in the reaction mixture. The reaction mixtures employed in the process of the present invention have a longer pot life than prior art reaction mixtures. The elastomers produced by this process are shrink stable.
摘要:
A process for the preparation of 1,4-3,6-dianhydro-hexitols from hexitols by elimination of water is described, characterized in that gaseous hydrogen halide is used as the acid dehydrating agent optionally with carboxylic acids, carboxylic acid halides and/or carboxylic acid anhydrides in quantities of up to 600 mol percent, based on the hexitols, as cocatalysts. The reaction is carried out in the absence of water and organic solvents, preferably using gaseous hydrogen chloride, temperatures of up to 300.degree. C. and pressures of up to 250 bar. Very high yields are obtained after working up of the product by distillation or extraction.
摘要:
Liquid dianhydrohexitol mixtures are prepared from diacylation products of hexitols and compounds such as organic carboxylic acids, carboxylic acid anhydrides, carboxylic acid halides, ketene and carbonic acid ester derivatives. More specifically, such diacylation products are simultaneously dehydrated and isomerized by subjecting them to a temperature of at least 130.degree. C. in the presence of a strong acid to yield diacylated dianhydro-hexitol isomer mixtures. These isomer mixtures are then converted to dianhydro-hexitol isomer mixtures by hydrolysis or transesterification. Suitable strong acids include proton acids, Lewis acids and heterogeneous acid catalysts (e.g., ion exchange resins). The mixtures of the present invention are characterized by a minimal tendency towards crystallization. These mixtures are particularly useful as chain extending agents in the production of polyurethanes.
摘要:
Liquid dianhydrohexitol mixtures are prepared from diacylation products of hexitols and compounds such as organic carboxylic acids, carboxylic acid anhydrides, carboxylic acid halides, ketene and carbonic acid ester derivatives. More specifically, such diacylation products are simultaneously dehydrated and isomerized by subjecting them to a temperature of at least 130.degree. C. in the presence of a strong acid to yield diacylated dianhydrohexitol isomer mixtures. These isomer mixtures are then converted to dianhydrohexitol isomer mixtures by hydrolysis or transesterification. Suitable strong acids include proton acids, Lewis acids and heterogeneous acid catalysts (e.g., ion exchange resins). The mixtures of the present invention are characterized by a minimal tendency towards crystallization. These mixtures are particularly useful as chain extending agents in the production of polyurethanes.
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:
A compound having a terminal isocyanate group is hydrolyzed to produce a polyamine having a urethane and/or a urea and/or a biuret group. More particularly, a carbamate is made by mixing an isocyanate prepolymer having urethane and/or urea and/or biuret groups present with aqueous base solutions at a temperature of from 0.degree. to 0.degree. C. and in quantities such that the equivalent ratio of hydroxyl to isocyanate groups is between from 0.3:1 to .gtoreq.1.01 to 1. The carbamate is then treated with an acid ion exchanger to form an amine. The amine is then removed from any other material which may be present. A preferred polyamine thus-produced corresponds to the general formula: ##STR1## in which each R radical may represent a divalent straight or branched-chain aliphatic radical; a divalent cycloaliphatic radical; a 4,4'- and/or a 2,4'-dicyclohexylmethane radical; or a 2,4- and/or 2,6-methyl cyclohexane radical. Such an amine may be reacted with a polyisocyanate and optionally with other known additives to form a polyurethane plastic or foam.
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.