Showing papers on "Polyurethane published in 1993"

Synthesis and properties of poly(hydroxyurethane)s

Abstract: Bis(cyclic Carbonate)s 1 were prepared by the reaction of bis(epoxide)s and atmospheric pressure of CO2 in the presence of sodium iodide and triphenylphosphine as catalysts at 100°C in high yield. Polyaddition of 1 and hexamethylenediamine (2a) or dodecamethylenediamine (2b) in dimethylsulfoxide or N,N-dimethylacetamide (DMAc) at 70 or 100°C for 24 h afforded corresponding poly(hydroxyurethane)s with Mn 20,000–30,000. When ethylenediamine (2c) or 1,3-propanediamine (2d) was used as a diamine, poly(hydroxyurethane)s with lower molecular weight were obtained. The presence of water, methanol, or ethyl acetate in the solvent had little effect on the Mn of the polymer obtained, because of the high chemoselectivity of the reaction of the five-membered cyclic carbonate and amine. Polyaddition of bis(cyclic carbonate) bearing ester groups and 2a also afforded the corresponding poly(hydroxyurethane) without aminolysis of the ester groups. Poly(hydroxyurethane) 3 obtained from the bis(cyclic carbonate) derived from bisphenol A was less soluble in organic solvents than model polyurethane 8 having no hydroxy groups obtained from 4,4′-isopropylidenebis(2-hydroxyethoxybenzene) and hexamethylene diisocyanate, and was thermally stable as well as 8.3 easily undertook crosslinking at room temperature by the treatment with hexamethylene diisocyanate or aluminium triisopropoxide in DMAc or tetrahydrofuran. The gel crosslinked by aluminium triisopropoxide regenerated the original polymer at room temperature by treatment with 1.5 equiv of 1.2M HCl in N-methylpyrollidinone for 1 h. © 1993 John Wiley & Sons, Inc.

Copolymers and non-porous, semi-permeable membrane thereof and its use for permeating molecules of predetermined molecular weight range

Abstract: The present invention relates to a biocompatible, hydrophilic, segmented block polyurethane copolymer which comprises 5 to 45 wt% of a hard segment, preferably a reaction product of an organic diisocyanate, a diamine and a polyol, and 95 to 55 wt% of a soft segment selected from a hydrophilic, hydrophobic and amphipathic oligomer such as aliphatic polyols, aliphatic and aromatic polyamines and mixtures thereof; the copolymer being capable of forming a non-porous, semi-permeable film of a tensile strength greater than 300 and up to 10,000 psi, an ultimate elongation greater than 300 % and up to 1,500 %, and a water absorption such that the sum of the volume fraction of absorbed water and the hydrophilic volume fraction of the soft segment exceeds about 100 % and up to about 2,000 % of the dry polymer volume and being permeable to cell nutrients and waste molecules of up to about 6,000 to 600,000 molecular weight and substantially impermeable to cells and particulate matter. A non-porous, semi-permeable, biocompatible film is formed from the block copolymer of the invention in the form of a flexible sheet or a hollow fiber. The present invention also relates to a method of permeating molecules of a predetermined molecular weight range while preventing the passage of larger molecular weight molecules, cells and condensed phases of matter between two fluids comprising interposing between the two fluids the non-porous film of the invention.

Room temperature curable silane-terminated polyurethane dispersions

Abstract: This invention provides aqueous dispersions of externally chain extended polyurethane compositions terminated by hydrolyzable and/or hydrolyzed silyl groups and containing anionic solubilizing or emulsifying groups, particularly carboxyl groups. The invention also provides methods of making both anionically and cationically stabilized polyurethane dispersions. This invention further provides polyurethane dispersions which are substantially organic solvent free (e.g. less than about 7 weight percent organic solvent) which cure to water and solvent resistant, tough, scratch resistant, preferably light stable (non-yellowing) polyurethane films. Such films are particularly useful as coatings for wood substrates, including wood floorings, furniture, and marine surfaces.

Ab initio characterizations of molecular structures, conformation energies, and hydrogen-bonding properties for polyurethane hard segments

Abstract: Ab initio Hartree-Fock and MP2 calculations with 3-21G and 6-31G * basis sets were conducted for a group of urethane model molecules and hydrogen-bonded dimers to study the intra- and intermolecular interactions for polyurethanes. Conformational structures and energies of internal bond rotations were calculated and compared with available experimental results. Three types of hydrogen bonds that formed between the urethane N-H group and (1) the urethane carbonyl oxygen, (2) the ester oxygen, and (3) the ether oxygen were studied. The vibrational frquency shifts of the N-H, C=O, and C-O-C stretching modes computed for the dimers at the HF/6-31G * level qualitatively agree with the experimental observations of polyurethanes and support the assignment of the 3295-cm -1 band to the N-H stretching mode in the N-H---O-(ether) hydrogen-bonding structure

Hydrophilic polyurethane gel foams, particularly for treating deep wounds, wound dressing based on hydrophilic polyurethane gel foams and method of manufacture

Abstract: Hydrophilic polyurethane gel foams are obtainable from a polyurethane gel defined in the description, from a water-absorbing material and from a non-aqueous foaming agent and can be used in medicine, in particular for the management of deep wounds and wound cavities. Wound dressings are obtainable with a polyurethane sheet as backing and a polyurethane gel foam composed of a polyurethane gel defined in the description, of a water-absorbing material and of a non-aqueous foaming agent.

Method for Manufacturing Self-Supporting Synthetic Trim Parts and Thus Manufactured Trim Parts

Abstract: In the method according to the invention, a layer of polyurethane elastomer for obtaining a polyurethane skin (5) is produced, in a first step, against a mould surface (1) In a second step, a reaction mixture for obtaining a polyurethane foam layer (6) is applied against this polyurethane skin (5) In a third step, a suitable polyurethane or polyisocyanurate reaction mixture for obtaining a rigid synthetic carrier (8) is applied against the polyurethane foam layer (6) In this way, a synthetic trim part is obtained which is easier to recycle This method can moreover also be performed easier

Grafting of polyurethane surfaces with poly(ethylene glycol)

Abstract: Films of a commercial poly (ether urethane), Pellethane 2363-80AE, were prepared through solvent casting from dimethyl formamide. The films were grafted with poly (ethylene glycol) (PEG) by a two-step procedure. In the first step, the film surfaces were treated with hexamethylene diisocyanate in toluene in the presence of triethylamine as a catalyst. In the second step, PEG 1500 was allowed to react in toluene with surface bound isocyanate groups. It was shown by ATR-IR, XPS, and contact angle measurements that the grafted surfaces were mainly composed of PEG, and that they were strongly hydrophilic. It was also shown that unreacted PEG was entrapped in the material, which influenced its mechanical and thermal properties. Extraction of the films with toluene eliminated the entrapped PEG, and the hydrophilicity as well as the PEG coverage of the surface decreased. However, a subsequent treatment with aqueous NaCl solution induced a molecular restructuring of the surface, increasing the amount of grafted PEG at the surface to a value close to the original one. (Less)

Polyurethane/polyurea elastomers

Abstract: Polyurethane/urea elastomers having an isocyanate equivalent index below 100, preferably from 15 to 80; containing an effective amount of polyisocyanate component, and an effective amount of an isocyanate reactive component comprising at least one polyamine and at least one polyol, wherein said elastomer contains from 1 to 60 equivalent percent amine per isocyanate equivalent.

A novel one-pot synthesis of hyperbranched polyurethanes

Abstract: The thermal decomposition of 3,5-dihydroxybenzoyl azide, to generate in situ the corresponding AB2-type dihydroxy isocyanate monomer, was found to give hyperbranched polyurethanes, whose structures were established using IR and NMR spectroscopy.

Aqueous coating compound, a process for its preparation and its use in processes for multilayered lacquering

Abstract: Aqueous coating compound containing a polyurethane resin-based hinder of I) from 60 to 100% by weight of a mixture of A) from 5-95% by weight of one or more self-emulsify-ing polyurethane resins in aqueous dispersion having a number average molar mass (Mn) of from 30000 to 300000 and containing carboxyl groups corresponding to an acid number of from 5 to 50, obtainable from a water dispersible polyurethane prepolymer having more than one free isocyanate group per molecule, by chain lengthening with water and B) from 95 to 5% by weight of one or more acrylated polyesters and/or acrylated polyurethanes having an acid number of from 5 to 50 in aqueous dispersion and II) from 0 to 40% by weight of one or more formaldehyde condensation resins and/or blocked polyisocyanates, the percentages by weight being based in each case on the resin solids content. The coating compounds are suitable in particular as basic lacquers for multi-coat lacquering. Coatings with good weather resistance are produced from them.

Synthesis and properties of liquid crystalline polyurethanes

Abstract: Liquid crystalline polyurethanes were prepared from 4,4′-bis(2-hydroxyethoxy)biphenyl (BHBP) and 2,4-tolylene diisocyanate (TDI). The effect of partial replacement of BHBP by 25–75 mol % poly(oxytetramethylene) diol (PTMO, Mn = 250) on the liquid crystalline properties was studied. The BHBP/TDI/PTMO polyurethanes were obtained by one- and two-step polyaddition. The polyurethanes were investigated by DSC, polarizing microscopy, x-ray, and IR spectroscopy. The molecular weight distribution was determined by GPC. The morphology of the polymers was investigated by the SALS method. Thermogravimetric investigations of the polyurethanes were also performed. All polyurethanes containing BHBP units have liquid crystalline properties. Partial replacement of BHBP by PTMO-250 considerably changes the phase transition temperatures and the range of mesophase occurrence. More homogeneous polyurethanes were obtained, if the two-step polyaddition method was applied. The polyaddition method affects the phase transition temperatures. © 1993 John Wiley & Sons, Inc.

Aqueous oil and water repellent compositions which cure at ambient temperature

Abstract: Fluorochemical compositions for treating textile fibers and fabrics to impart oil and water repellency without thermal treatment are provided. The compositions comprise an aqueous, substantially organic solvent free, solution or dispersion of (a) a fluorochemical acrylate copolymer comprised of a fluorinated acrylate monomer, polyalkylene glycol acrylate or methacrylate, and polyalkylene glycol diacrylate or dimethacrylate; and (b) a polyalkoxylated polyurethane having pendant perfluoroalkyl groups comprised of an aliphatic or aromatic tri- or higher order isocyanate, a fluorinated alcohol, amine, or mercaptan, and a poly(oxyalkylene) diol or dithiol.

Polyurethane coating composition derived from polyester polyol containing long-chain aliphatic polyol

Abstract: A coating composition is disclosed comprising: (a) an aqueous medium, (b) an water-dispersible polyurethane resin that is the reaction product of a mixture comprising: (1) a hydroxy-functional polyester component that is the reaction product of a mixture comprising a carboxylic acid component comprising at least two carboxylic acid functional groups, a long-chain aliphatic polyol having 18 to 60 carbon atoms, and a short-chain polyol having 12 or fewer carbon atoms, (2) a multifunctional compound having at least one active hydrogen group and at least one water-stabilizing group, (3) an active hydrogen-containing capping or chain extending agent, and (4) a polyisocyanate, and (c) an aminoplast crosslinking agent.

Production and use of open cell rigid polyurethane foam

Abstract: A method of producing an open cell rigid polyurethane foam which comprises reacting a polyol with a polymethylene polyphenyl polyisocyanate prepolymer with a monool exemplified by diethylene glycol monomethyl ether by use of a substitute such as 1,1-dichloro-1-fluoroethane or methylene chloride as a volatile blowing agent, or a mixture of the volatile blowing agent with water, for trichlorofluoromethane as a blowing agent in the presence of a catalyst, a foam stabilizer and a cell opening agent. The resultant open cell rigid polyurethane foam has a cell size of about 200-250 microns, and is suitable for use, for example, as a core material in a vacuum heat insulating material. The foam may be enclosed in a container under a vacuum of 0.1-0.01 mmHg readily attainable to provide a vacuum heat insulating material of a high heat insulating performance.

Effect of polyol type on the physical properties and thrombogenicity of sulfonate-containing polyurethanes.

Abstract: Polyetherurethanes (PEUs) based on polytetramethylene oxide (PTMO) as the polyol, and derivatized with propyl sulfonate functionality, have previously been shown to possess antithrombotic properties. In this article, the bulk physical properties of sulfonated and nonsulfonated polyurethanes containing either polyethylene oxide (PEO) or PTMO as the soft segment are studied. The in vitro shape-change of platelets in contact with these surfaces, and their ex vivo blood-contacting response are also investigated. It was found that PEO-base was physically weaker than PTMO-base, which is attributed to a lower degree or phase separation in the former. In the dry state, sulfonation enhanced the physical properties for PTMO-containing polyurethane (PTMO-SO3-0.20), but weakened the PEO-containing polyurethane (PEO-SO3-0.15). In vitro platelet spreading studies showed the lowest degree of platelet spreading and also the lowest platelet density on PEO-base, while platelet spreading and density on the other three materials and polyethylene (PE) was greater. The thromboresistance of these materials was evaluated using a canine arteriovenous series shunt ex vivo. It was determined that PTMO-SO3-0.20 was the least thrombogenic, followed by both PEO-base and PEO-SO3-0.15, and that PTMO-base was the most thrombogenic.

Water-blown polyurethane integral skin foam

Abstract: The invention relates to water blown integral skin polyurethane foams made with a particular isocyanate quasi-prepolymer and resin side ingredients to yield a foam having good overall mechanical roperties. The isocyanate quasi-prepolymer component of the present invention comprises from 0.5 weight percent to 30.0 weight percent or less uretonimine-carbodiimide-modified diphenylmethane diisocyanate, from 50 weight percent to 80 weight percent 4,4'-diphenylmethane diisocyanate and reacted with from 15 weight percent to 40 weight percent of a polyether polyol containing predominately secondary hydroxy groups and having an average molecular weight from about 2,000 to 10,000, an average functionality from 1.5 to about 3.2, and a hydroxyl number from about 20 to 60. The resin side component comprises a high molecular weight polyether polyol with an average functionality from 1.5 to about 3.2, water as a blow agent, and optionally an mono- or di-functional alcohol composition having from 8 to about 30 carbon atoms. The components, when injected or poured into a preheated mold, can tolerate mold temperatures from 105° F. to 135° F. and can be demolded in less than 150 seconds to yield and integral skin foam having little or no bubbles or pores visible to the eye. The foam produced thereby has a compression set of 30 percent or less, high tensile strength, and high tear strength.

Multilayer coextruded material for medical grade products and products made therefrom

Abstract: The present invention provides a non-PVC, non-DEHP material that can be used for medical grade tubing. Additionally, the present invention provides medical grade tubing made from such a material. To this end, the present invention provides a medical grade tubing comprising a multilayer coextruded structure including: a layer comprising a blend of polyurethane and polyester; and a layer comprising a blend chosen from the group consisting of: polypropylene, ethylenevinyl acetate, and polyurethane; polypropylene and styrene-ethylene-butylene-styrene; polypropylene, styrene-ethylene-butylene-styrene, and ethylenevinyl acetate; polypropylene, ethylenevinyl acetate, styrene-ethylene-butylene-styrene, and thermoplastic polyester elastomer; polypropylene, ethylenevinyl acetate, styrene-ethylene-butylene-styrene, thermoplastic polyester elastomer, and polyurethane; polyester, thermoplastic polyester elastomer, and polyurethane; polyester and polyurethane; and polypropylene, styrene-ethylene-butylene-styrene, and polyurethane.

Bioabsorbable composites. II: Nontoxic, L-lysine-based poly(ester-urethane) matrix composites

Abstract: Bioabsorbable composites were fabricated from poly(D, L-lactide-urethane) matrix reinforced with poly(glycolic acid) (DEXON) surgical mesh. The crosslinked polyurethane matrix was formed from the reaction of ethy1–2, 6-diisocyanatohexanoate and poly (D, L-lactide) triol, initiated from glycerol; the ultimate degradation products of this matrix, L-lysine, lactic acid, glycerol, and CO2, are all nontoxic, naturally occurring metabolites. The composites were fabricated by two processing methods, with the final composite structures displaying very different physical properties. Composites fabricated by vacuum bag molding displayed tensile strength and modulus of 66 MPa and 468 MPa, respectively, with total elongation of 39%. Composites fabricated by the same method, but whose final cure included 24 h at 5000 psi, displayed tensile strength and modulus of 86 MPa and 3.4 Gpa, respectively, with total elongation of 18%, suggesting a more fully developed matrix/fiber interphase and a reduction in microvoids, which lead to lower force failures. As poly(D, L-lactide) prepolymer molecular weights decreased, tensile strengths and glass transition temperatures of the polyurethane networks increased. These trends were attributed to increased hydrogen bonding with an increased crosslink density. The composites were sensitive to cyclic loading, regardless of the processing technique, suggesting an inefficient transfer of energy from the matrix into the load-bearing fibers. This weakness was confirmed by SEM microscopy, which revelaed a gap at the fiber/matridx interface of an unfatigued composite sample, poly(D, L-lactide-urethane) matrix composites were found to be unique since they can be custom shaped when heated above the glass transition of the matrix. DSC revelaed the glass transitions for the matrices of around 60°C. The composites were easily shaped above this temperature, yet remained rigid at biological temperature.

Aqueous polyurethane dispersions

Abstract: Aqueous polyurethane dispersion in which the polyurethane is made by chain-extension of a prepolymer, and optionally including another polymer (particularly acrylic), wherein the prepolymer incorporates a dimer acid-based polyesterpolyol and also a low molecular weight cycloaliphatic and/or aromatic polyol and/or polyacid and wherein any low molecular weight cycloaliphatic or aromatic polyol is incorporated as a component of the polyester polyol and/or is used as such in the prepolymer synthesis, and any low molecular weight cycloaliphatic or aromatic polyacid is only or substantially only used as such in the prepolymer synthesis.

Urethane oligomers and polyurethanes

Abstract: A urethane is formed in a new way, without requiring the use of isocyanates. The urethane is formed by reacting a compound containing a plurality of cyclocarbonate groups with a diamine in which the two amine groups have different reactivities with cyclocarbonate, so as to form a urethane oligomer with amine end groups. The urethane oligomer can then be reacted in several different ways to form polyurethane.

Characterization of Polyurethane Foams by Mid-Infrared Fiber/FT-IR Spectrometry

Abstract: The use of a mid-infrared transmitting fiber to monitor the cure process of a polyurethane foam is described. A chalcogenide fiber was situated between the spectrometer and a remote detector, but passed through the center of a polyurethane foam. This fiber was used as an internal reflectance element to observe changes in the polyurethane curing process. The appearance and disappearance of absorbances in the NH-stretching, carbonyl stretching (free urea and urethane, hydrogen-bonded urethane, and monodentate and bidentate hydrogen-bonded urea), isocyanate, and isocyanurate regions were monitored. These changes provided information about the reaction kinetics and morphological development of the foam.

Binders for powder coatings

Abstract: Binders for powder coatings comprising A) a solid unsat-urated polyester and B) a polyurethane comprising (meth)-acryloyl groups. These polyester-containing mixtures are distinguished by an improved blocking stability as compared with polyurethane alone.

Polyurethane resins, process for producing the same, and uses thereof

Abstract: The improved polyurethane resin has a number average molecular weight of 2,000-200,000 and is prepared by reacting an organic diisocyanate compound, a polymer diol compound, a chain extender and a terminator. It is characterized by having at least one group selected from hydrazine groups, hydrazide groups and semicarbazide groups in the molecule. The polyurethane resin can be produced using a chain extender and/or a terminator that have at least one hydrazine group or hydrazide group. This polyurethane resin can be dispersed in water in the presence of an emulsifier or by first introducing free carboxyl groups into the molecule of the resin and then dissolving or dispersing it in an aqueous alkali solution or by first introducing tertiary amino groups into the molecule of the resin and then dissolving or dispersing it in an aqueous acid solution. The water-based polyurethane resin can be used either as a binder for water-based printing inks or as a water-based laminating adhesive. The water-based printing ink and/or the water-based laminating adhesive of the present invention can be used for laminates producing.

Degradation of polyurethane foams used in the Même breast implant

Abstract: The release of toluene diisocyanate derivatives from polyurethane foam covers that were removed from the Měme breast implant was studied. The polyurethane foam covers as retrieved from the implants were contaminated on average with 2,4- and 2,6-toluene diamine (TDA), 2,4- and 2,6-toluene diisocyanate (TDI), and toluene isocyanate amine (TIA) at the 1086 ppm level (combined TDA, TDI, and TIA). When cleaned foam was incubated in Ringer's solution at 37°C for periods ranging from 6–35 days, 4.6 ppm/day of TDA, TDI, and TIA (combined) was formed; the projected annual degradation rate of the foam under these conditions was estimated to be about 0.8%. When cleaned foam was incubated dry at 37°C, 1.5 ppm/day of TDA, TDI, and TIA (combined) was produced. Hence, the polyurethane foam covers used in the Měme breast implants are susceptible to both thermal and hydrolytic degradation under simulated physiological conditions. © 1993 John Wiley & Sons, Inc.

Polyurethane coating composition derived from long-chain aliphatic polyol

Abstract: A coating composition is disclosed comprising: (a) an aqueous medium, (b) a water-dispersible polyurethane resin that is the reaction product of a mixture comprising: (1) a long-chain aliphatic polyol having 18 to 60 carbon atoms, (2) a multifunctional compound having at least one active hydrogen group and at least one water-stabilizing group, (3) an active hydrogen-containing capping and/or chain extending agent, and (4) a polyisocyanate, and (c) an aminoplast crosslinking agent.

Process for preparing polyurethane foam

Abstract: A process for preparing a polyurethane foam according to the one-shot foaming process by reactions between a polyisocyanate and an active hydrogen-containing component including water and an organic polyol wherein said reactions are conducted in the presence of a salt of a tertiary amine and a carboxylic acid having hydroxyl functionality.

Foamed polyurethane-forming composition, foamed polyurethane and process making the same

Abstract: Foamed polyurethanes substantially free from non-uniform density distribution are obtained by dispersing an inert gas with mechanical stirring into a foamed polyurethane-forming composition containing substantially no blowing agent and comprising (1) an organic polyisocyanate component, (2) a polyol component comprising a high molecular weight polyol (A1) and a low molecular weight polyol (A2), (3) a dehydrating agent (B) and optionally organic microballoons, and curing the resulting composition containing therein the inert gas substantially homogeneously distributed. Foamed polyurethanes thus obtained are lightweight and of reduced warpage after processing and are suitable for model materials.