摘要:
The present invention relates to polyurethanes containing secondary amide groups in the backbones of the polyurethanes, wherein the secondary amide groups (calculated as NH—CO—, MW 43) are present in an amount of 1 to 14% by weight, based on the weight of the polyurethanes, and correspond to the formula —X1—R1—NH—C(O)—R2—X2— (I) wherein X1 and X2 are the same or different and represent the groups obtained by removing a hydrogen atom from a hydroxy group or a primary or secondary amino group and R1 and R2 are the same or different and represent linear or branched hydrocarbon groups that are optionally substituted by groups that do not contain isocyanate-reactive hydrogen atoms. The present invention also relates to one-component, thermoset compositions containing the polyurethanes with secondary amide groups in the backbone and a cross-linking component that is reactive with amide groups. Finally, the present invention relates to coatings, sealants and adhesives prepared from these one-component, thermoset compositions.
摘要:
The invention relates to a foamable composition comprising at least two parts. The first part comprises a polyol, a thixotropic gelling agent, a blowing agent, a urethane reaction catalyst and a isocyanurate reaction catalyst. The second part comprises at least one isocyanate. A foam mass can be prepared by combining the first part polyol component with the second part isocyanate component. The composition is foamable under water and exhibits, upon foaming under water, substantially the same wet foam density and dry foam density. The invention also relates to a method of repairing or reinforcing structural members having defects such as spike holes left after spike removal from railroad ties during road bed maintenance or repair by means of the foamable composition.
摘要:
The present invention relates to water-soluble or water-dispersible polyurethanes of a water-dispersible polyurethane prepolymer having terminal isocyanate groups and a primary or secondary amine having at least one ionogenic or ionic group, and to the salts thereof. The novel polyurethanes can be used as auxiliaries in cosmetology and pharmacy and, in particular, as hair lacquers having enhanced ease of washoff.
摘要:
The present invention relates to a continuous shaped article such as a polyurethaneurea fiber and a polyurethaneurea film having a birefringence index (&Dgr;n) of from at least 1.0×10−4 to 8.0×10−4 in a nontensile state, a crosslinking density at an elongation of 100% (N100) of at least 5.0×1026/m3, a crosslinking point density at an elongation of 400% (N400) of from 4.0×1026 to 3.0×1027/m3, and a crosslinking point density at the time of breakage (Nt) of at least 1.6×1027/m3, wherein the ratio of the crosslinking density at an elongation of 400% to that at an elongation of 100% (N400/N100) is from 0.9 to 1.3, and a process for producing the same. The present invention has made the continuous shaped article show an initial stress, a strength at break and an elongation at break which are sufficiently high, and a small rise in the stress in the medium elongation range.
摘要:
Methods for reducing the electrode impedance of implantable biosensors by coating the surface of the biosensor with a uniform hydrogel which allows unimpeded water movement around the sensor are provided. The surface coatings are compositions which are biocompatible and are capable of water uptake of at least 120% of their weight, more preferably at least 200% of their weight. Upon the uptake of water, the hydrogels used in the present invention will also swell and provide a layer of water around the electrodes to which the hydrogels are attached. The hydrogels can be prepared from (a) a diisocyanate, (b) a hydrophilic polymer which is a hydrophilic diol, a hydrophilic diamine, or a combination thereof, and optionally, (c) a chain extender.
摘要:
The invention concerns a polyurethane elastomer containing structural units of type (a), in which: the group —O—R1—O—is a macrodiol group with a molecular weight of approximately 500 to 10000, R2 is a bivalent aliphatic, cycloaliphatic and/or aliphatic-cycloaliphatic group; and X is a short-chain olefinically unsaturated group, Y is NH or O, n is an integer from 1 to 10 and m is an integer of at least 4. The invention also concerns a method of preparing this polyurethane elastomer which can be melt-spun to form fibres or melt-extruded to form foils. The fibres or foils can be exposed to energy-rich radiation such that crosslinking of the polyurethane occurs. Fibres according to the invention display superior properties in terms of textile-mechanical properties, in particular good tensile strength, elongation at tear, residual elongation and heat distortion temperature.
摘要:
A curing agent composition for an epoxy resin which comprises (B) a reaction product obtained from (a) an amine compound represented by formula (I): wherein R1 and R2 each represent an alkyl group having 1 to 8 carbon atoms, of R1 and R2 are connected together to form an alkylene group which may contain an oxygen atom or a nitrogen atom; and n represents 1 to 6, (b) a polyamine compound comprising a dicarboxylic acid dihydrazide, (c) an organic polyisocyanate, and, optionally; (d) an epoxy compound.
摘要:
Certain secondary aliphatic diamines are excellent chain extenders in the formation of polyurethanes, polyurea-polyurethane hybrids, and polyurea polymers, both elastomers and coatings, from both monomeric polyisocyanates and isocyanate-terminated prepolymers using the high-pressure impingement mixing reaction technique. These diamines include 1,4-di(alkylamino)cyclohexanes, 1-methyl-2,4-di(alkylamino)-3,5-dialkylcyclohexanes, N,N′-dialkyl isophoronediamine, 1,3-di(1′methyl-1′-alkylaminoethyl)benzene, and 1,6-di(alkylamino)hexane. These chain extenders may be used alone or in combination with other polyamines and with polyols. A broad spectrum of polymeric materials can be formed with a range of diverse properties.
摘要:
The present invention provides a flexible two component polyurethane and method for producing the polyurethane. The cured polyurethane is flexible, durable and weather resistant. The polyurethane is suitable for use as a protective layer on various substrates. The flexible polyurethane is the reaction product of solvent-free reaction components. The first component includes one or more polyols, optionally, one or more diols, and a catalyst. The second component includes a primary aliphatic isocyante crosslinker.
摘要:
The present invention relates to moisture-curable compositions which have a) a content of (cyclo)aliphatically-bound isocyanate groups (calculated as NCO, MW 42) of 0.2 to 22% by weight and b) a content of succinyl urea groups (calculated as —NH—CO—N—, MW 57) of 0.1 to 14% by weight, and c) an equivalent ratio of (cyclo)aliphatically-bound isocyanate groups to succinyl urea groups of 4:1 to 1:1, wherein the preceding percentages are based on resin solids content of the moisture-curable compositions. The present invention also relates to coating, adhesive or sealing compositions containing these moisture-curable compounds as the binder.