摘要:
The present invention relates to the use of thermosetting polyurethane urea reactive adhesive compositions which are stable at ambient temperature but rapidly set at higher temperatures, wherein the adhesive comprises stabilized finely-divided polyisocyanates of retarded reactivity of which 0.1 to 25% of the NCO-groups are surface-modified and higher and/or lower molecular polyamines (optionally with polyols as additional reactive components). An important feature of these thermosetting reactive adhesive compositions is their capacity for storage at ambient temperature and their spontaneous increase in viscosity at relatively low heating temperatures which prevents the adhesive from running off during the heating period when applied to vertical surfaces.
摘要:
Aromatic uret dione diurea diamines corresponding to the formula ##STR1## in which X, Y, m and n are as defined herein are produced by reacting an aromatic diamine with a diisocyanate corresponding to a specified formula in a molar ratio of diamine to diisocyanate of at least 1.8 to 1. These diamines are particularly useful in the production of elastomers.
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:
Low molecular weight 4,4'-diphenylmethane-uretdione-diisocyanates corresponding to the formula: ##STR1## wherein n is a number from 0 to 1,are made by dimerizing diphenylmethane-4,4'-diisocyanate at a temperature of 50.degree. C. or less in a mixture of non-polar and moderately polar solvents in the presence of a dimerization catalyst. The dimerization product may then be worked up at low temperatures (i.e., .ltoreq.50.degree. C.). The dimerization products of diphenylmethane-diisocyanate thus obtained generally have only a small amount of oligomeric uretdione-diisocyanates present. These dimerization products may be used advantageously in the synthesis of polyurethanes.
摘要:
Diisocyanates corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 (an isocyanate-containing radical) are as defined herein are made by several processes. These diisocyanates may be made by phosgenating the diamine in which the diisocyanate is based. They may also be produced by treating the bis-urethane of the tertiary alcohol corresponding to the diisocyanate with phosgene. Such diisocyanates may also be made by treating a specific type of bis-urea with hydrogen chloride. The diisocyanates corresponding to the above-given formula are particularly useful in the production of polyurethanes having good flame-proof and mechanical properties.
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.
摘要:
The present invention is directed to a process for the production of compact or cellular, elastomeric moldings having a compact skin based on polyurethane urea elastomers prepared from(a) organic polyisocyanates,(b) relatively high molecular weight polyhydroxyl or polyamino compounds containing at least two reactive hydrogen atoms,(c) diaminodiphenyl ureas as chain-extending agents and optionally,(d) catalysts,(e) small quantities of ethylene glycol,(f) other chain-extending agents and/or cross-linking agents,(g) blowing agents and(h) auxiliaries and/or additives, which is characterized in that the chain-extending agents (c) are diaminodiphenyl ureas corresponding to formula I ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 may be the same or different and represent hydrogen or a C.sub.1 -C.sub.6 alkyl radical and wherein the NH.sub.2 groups are in the m- and/or p-position to the urea group.The present invention is also directed to the RIM elastomers produced by this process.
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 solid reaction products of aliphatic, cycloaliphatic or araliphatic mono- and/or polyisocyanates and organic, weakly acid mono- and/or polycarboxylic acids for the production of cellular plastics articles and particularly polyurethane foams. The products of the present invention may also be in the form of mixtures with carboxylic acids. The products are suitable for the production of cellular or porous plastics articles, but are preferably used in the preparation of cellular thermoplastic polyurethanes and semi-rigid and particularly rigid polyurethane integral skin foams having a compact outer skin formed by foaming the reaction mixture in closed molds.