Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-07-14
2001-01-23
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S450000, C525S453000, C525S454000, C525S460000, C528S055000, C528S056000, C528S057000, C528S058000, C528S084000, C604S027000, C604S508000, C604S523000, C623S002100, C623S001100, C606S191000
Reexamination Certificate
active
06177523
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to functionalizable and crosslinkable polyurethanes, the process of functionalizing, the process of crosslinking and the functionalized and crosslinked products derived from the functionalizable and crosslinkable polyurethanes. In particular, the present invention is concerned with crosslinked and functionalized polyether polyurethanes, the products thereof and their uses in industrial products, cosmetics and medical devices.
2. Description of Related Art
Polyurethanes that contain carboxyl groups in the backbone are known in the art. U.S. Pat. No. 4,743,673 describes the preparation of hydrophilic carboxylic acid containing polyurethanes by using diesters of dihydroxyl carboxylic acids such as the butyl ester of tartaric acid, to form polyurethane intermediates. The polyurethane intermediates are saponified and neutralized to form free carboxyl groups. This patent describes that the carboxyl groups introduce reactive sites for attaching side groups and for curing procedures. The carboxyl groups also provide sites for light or loose crosslinking curing with ammonium dichromate which can oxidize or complex with the acid group. This patent has the shortcoming that only ammonium dichromate is used and it is toxic and such products are not useful in cosmetics and medical devices.
U.S. Pat. No. 3,412,054 describes a water dilutable polymer for use as surface coatings and inks. The polyurethanes are prepared by reacting an amine or ammonia with a urethane polymer containing free carboxyl groups to form a polymer including a quaternary ammonium salt. This patent describes those polymers containing alkanoic acids that form quaternary ammonium groups in the presence of an amine but do not form the amide. Accordingly, the ammonium salt is formed and it can be functionalized but the quarternary group ionizes readily in water and is not stable.
U.S. Pat. No. 5,254,662 describes that polyurethanes prepared from the reaction of an organic diisocyanate with polycarbonate glycol can be chain extended with a diol, diamine or a mixture of diamine and alkanolamine. This patent discloses that the polyurethane formed is biostable and can be used in implantable pacemakers, vascular grafts, mammary prostheses and as other products which are intended to be placed in the body.
It is desirable to form a functionalized and crosslinked polymer using a polyether and polycarbonate polyurethane which can be used in industrial products, cosmetics and medical devices.
SUMMARY OF THE INVENTION
It has now been found unexpectedly that polyurethanes including one or more pendant ester groups can react under certain conditions with an amine equivalent to form an amide unit. The amine equivalent refers to one, two or more amine groups in a molecule. A polyurethane intermediate can be prepared from the amine-reactive pendant ester of a dihydroxypolyacid or dimethylolalkanoic acid. For example, the reaction can be performed by dissolving the polyurethane intermediate comprising the amine-reactive pendant ester group of the dihydroxypolyacid, in a substantially nonaqueous solvent containing less than about 50% water, adding a selected amount and type of amine, evaporating the solvent and heating the resultant product. This reaction is unexpected since it is known that a primary amine such as hexanediamine reacts rapidly with the carboxylic group of a dihydroxy alkanoic acid in water, but it has been found that the same amine does not react in water with the acid group of the polymer to form an amide link. It is believed that a loose cross-link forms between the amine salt of the carboxylic acid of the polymer and adjoining urethane group, preventing elimination of water and completion of the reaction to the amide. Also, steric hinderance effects may prevent reaction of amines with certain pendant acid and ester groups.
The present invention provides a polymer that can be functionalized with short and long chain hydrophobic and hydrophilic mono and polyamines and the functionalized polymer can be further reacted with compounds comprising an active hydrogen such as a fatty acid, drug, enzyme, pharmaceutically active agent (PAA), antioxidant, UV stabilizer and an unsaturated acid to crosslink the polymer by photopolymerization and free radicals and bond the polymer to polymers comprising an active hydrogen.
The ester group can be incorporated into hydrophobic, hydrophilic and amphiphilic polyether polyurethanes formed by liquid casting, prepolymer and one-shot methods. For example, suitable polymers are disclosed in U.S. Pat. Nos. 5,563,233, 4,789,720, 5,254,662, 5,118,779, 4,285,073, and as described in the section on Polyurethanes in volume II, 1969 copyright of Encyclopedia of Science and Technology, pages 506-553.
Preferably, an alkyl ester of a dimethylolalkanoic acid or dihydroxypolyacid, including 2,2-(dihydroxymethyl)propionic acid and tartaric acid, can be incorporated into a polyurethane to form a polyurethane intermediate. The polyurethane intermediate can be formed from the reaction product of an alkyl ester of a dimethylolalkanoic acid or dihydroxypolyacid, a polyoxyalkylene diol having a number average molecular weight of about 100 to about 20,000 comprising one or more of polyoxyethylene diol, polybutylene oxide, polyoxypropylene diol, polyoxytetramethylene diol, polyether polycarbonate diol and polydimethylsiloxane polyoxyalkylenecopolymer, an alkylene glycol selected from ethylene glycol, 2-methyl-1,3 propanediol, propylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, diethylene glycol, 1,4-butane diol, neopentyl glycol, hexane diol, 2,-4-pentane diol, cyclohexanediol, cyclohexanedimethanol and 2-ethyl-1,3-hexane diol, an organic diisocyanate and a water equivalent.
A suitable substantially hydrophilic polyurethane intermediate can be formed from the reaction product of an alkyl ester of a dimethylolalkanoic acid or dihydroxypolyacid, a hydrophilic polyoxyethylene diol in an amount of at least about 60% by weight of the reaction mixture, an organic diisocyanate, with a water equivalent in an amount comprising from about 0.01% to about 0.8% by weight of the reaction mixture in an equivalent mole weight ratio of NCO to OH of the hydroxyl groups of the diol, alkylene glycol, organic diisocyanate and water of from about 0.4 to about 1.2. Alternatively, a substantially hydrophilic polymer can be formed from a reaction mixture not including alkylene glycol. By definition, all amounts of reactants are based on weight percent of the total reactants used in the reaction mixture unless otherwise specified.
A suitable substantially amphiphilic polyurethane intermediate can be formed from the reaction product of a mixture of a hydrophilic diol and a hydrophobic diol one of which incorporates an alkyl ester of a dimethylolalkanoic acid or dihydroxypolyacid. For example, the hydrophilic diol can be hydrophilic polyoxyethylene diol and the hydrophobic diol can be polyetherpolycarbonate diol comprising butane, pentane and hexane diols or polydimethylsiloxane polyoxyalkylene copolymer or mixtures thereof. A water equivalent of about 0.001% to about 0.70% by weight of the reaction mixture and an equivalent mole weight ratio of NCO to OH of the hydroxyl groups of the diol, alkylene glycol, organic diisocyanate and water of about 0.60 to about 1.2 is preferably used in the reaction mixture.
A suitable substantially hydrophobic polyurethane intermediate is formed from an alkyl ester of a dimethylolalkanoic acid or dihydroxypolyacid, at least about 5% to about 80% of a hydrophobic diol, an alkylene glycol, an organic diisocyanate, a water equivalent of about 0.001% to about 0.70%, and an NCO to OH ratio of the hydroxyl groups of the diol, alkylene glycol, diisocyanate and water of about 0.7 to about 1.2 of the reaction mixture. The polymer can be formed as a prepolymer of a diisocyanate and polyoxyalkylene diol such as polyether polycarbonate and then chain extended with an alkyl ester of a dimethylolalkanoic acid or d
Reich Murray H.
Teffenhart John
Bagwell Mel. D.
Cardiotech International, Inc.
Mathews, Collins Shepherd & Gould P.A.
Seidleck James J.
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