WO1988000214A1

WO1988000214A1 - Polyurethane polymers prepared from mixed alkylene glycol resins

Info

Publication number: WO1988000214A1
Application number: PCT/US1987/001457
Authority: WO
Inventors: Stephen D. Reduker; Charles K. Kliment
Original assignee: Tyndale Plains-Hunter, Ltd.
Priority date: 1986-06-26
Filing date: 1987-06-15
Publication date: 1988-01-14
Also published as: AU7780787A

Abstract

A hydrophilic, thermoplastic polyurethane polymer of improved dimensional stability and mechanical strength having an average molecular weight of from about 10,000 to about 200,000 produced by reacting (A) an organic diiscocyanate with (B) a blend of glycol components comprising (i) ethylene glycol and/or diethylene glycol, (ii) a polyoxyethylene glycol having an average molecular weight of from about 400 to about 20,000 and (iii) a polyoxytetramethylene glycol having an average molecular weight of from about 650 to about 2,900, and (C) a minor amount of water. The polymers are particularly useful in the form of a film product such as gloves and condoms. Other uses are as low friction coatings, body implants and active agent release media.

Description

POLYURETHANE POLYMERS PREPARED FROM MIXED ALKYLENE GLYCOL RESINS

Technical Field

This invention relates to polyurethane polymers, and in particular to hydrophilic polyurethane polymers prepared from a combination of certain alkylene glycols and to coatings, films, carrier systerns and various articles based on the polymers.

Background of the Invention

In U.S. Patent Nos. 3,822,238 and 3,975,350, there is described a class of hydrophilic polyurethane polymers which, on contact with an aqueous medium, absorb water with concomitant formation of a stable, water-insoluble hydrogel. These polymers owe their hydrophilic character to the presence in the polymer backbone of polar sites which are controlled by the proper selection of a reactive hydrogen group terminated resin used in the polymer synthesis. Such resins include a variety of polyamines, polyglycols, polycarboxylic acids, polyphosphoric acids and physical blends of such resins as well as resins having mixed functionality. These polyurethanes may be thermoplastic or thermosetting depending on the degree of cross-linking. In general, difunctional reactants tend to give thermoplastic polymers whereas multifunctional reactants such as triisocyanates tend to give thermoset polymers. The preferred polymers are said to be of the thermoset type.

In the water swelled state, the polyurethane polymers of the cited patents vary from gel-like to soft and pliable and in the dry state from soft to hard and machinable. Suggested uses are as coatings, linings, dialysis membranes, absorbents, controlled release agents, swellable fabrics, gauzes, solubilizing packaging components, water transmitting coated

fabrics, water swelling caulks, wet friction elastomers, artificial leather, gas filters, dentures, hair sprays, nail polishes and oil resistant shapes.

Hydrophilic polyurethane polymers have also been disclosed in which the chemical configuration is specifically tailored to provide certain features and characteristics. For instance, in U.S. Patent No. 4,156,066,. there is described a hydrophilic polyur- ethane having lactone groups in the polymer backbone. The lactone may be opened by hydrolytic cleavage to form carboxylic groups which render the polymer soluble in alkaline medium. Other specialized hydrophilic polyurethane polymers are the polyurethane diacrylates of U.S. Patent No. 4,359,558 and the polyurethane quaternary ammonium salts of U.S. Patent No. 4,451,635.

Description of the invention

A polyurethane polymer of the hydrophilic type has now been found, the formulation and properties of which are not obviously derivable from the known art and the provision of said polymer and its uses constitute the object and purpose of the invention.

Broadly, the novel polyurethane of the invention is a hydrophilic, thermoplastic, essentially linear polymer which is obtained by reacting, in the

presence of a small quantity of water, a difunctional polyisocyanate and an alkylene glycol component comprising a mixture of

(1) ethylene glycol and/or diethylene glycol;

(2) a long-chain, water-soluble polyoxyethylene glycol; and

(3) a polytetramethylene glycol.

In formulating the herein polyurethane, use is made of the known technique of controlling its degree of hydrophilic character by adjusting the ratio of hard to soft segments in the polymer backbone. By hard segment is meant the more rigid chain fragment derived from the ethylene glycol/ diethylene glycol while soft segment refers to the more flexible chain fragment derived from the long-chain polyoxyethylene glycol. Thus, the proportions in which the long-chain polyglycol and the low molecular weight glycol are used depends on the hydrophobic-hydrophilic balance that is desired in the final polymer product. Increasing molecular weight of the long-chain polyoxyethylene glycol and/or the amount of this component imparts strong hydrophilic properties to the polymer. This effect may be counter-balanced by increasing the proportions of

low molecular weight glycol. For a more detailed account of this polymer technique, reference is made to previously cited U.S. Patent No. 4,156,066. What is surprising and unexpected is that the mechanical properties of the prior hydrophilic polyurethane polymers aforesaid generally can be further improved, particularly with respect to dimensional.stability and strength, by replacing a portion of the soft and/or hard segment with -OCH₂CH₂CH₂CH₂- units derived from the polytetramethylene glycol, component (3) of the above-defined alkylene glycol mixture. These improved properties will be commented on subsequently herein.

So far as can be ascertained, the polyurethane polymer of the invention will overall fall within the average molecular weight range of from about 10,000 to 200,000, the polymer being further defined as comprising the reaction product of: (A) an alkylene glycol component comprising a mixture of (1) ethylene glycol and/or diethylene glycol, (2) a polyoxyethylene glycol having an average molecular weight of from about 400 to about 20,000 and (3) a polyoxytetramethylene glycol having an average molecular weight of from about 650 to about 2,900; (B) an organic diisocyanate; and (C) a minor amount of water. Preferably, the mixture of alkylene glycols will comprise, per 100 parts by weight of total reaction mixture (A+B+C), of (i) from about 2 parts to about 15 parts by weight of ethylene glycol and/or diethylene glycol, (ii) from about 10 to

about 80 parts by weight of polyoxyethylene glycol and (iii) from about 10 to about 60 parts by weight of polyoxytetramethylene glycol. A more preferred alkylene glycol formulation comprises (i) from about 4 to about 10 parts by weight of ethylene glycol and/or diethylene glycol, (ii) from about 22 parts to about 59 parts by weight of polyoxyethylene glycol and (iii) from about 20 to about 40 parts by weight of polyoxytetramethylene glycol on the same basis.

In all of the reaction mixtures, the proportions of alkylene glycol and diisocyanate will be such as to provide an NCO/OH ratio of about 1 to slightly less than 1, usually about 0.98, i.e., from about 1:1 to about 0.98:1.

Enough water should be present in the reaction mixture to assist in the workup of the mixture, e.g., by lowering the viscosity. While this is achievable in some cases without foaming, by reason of trace amounts of water often present in commercial alkylene glycols or which result from pickup of atmospheric moisture by the alkylene glycols due to their hygroscopicity, preferably sufficient water will be present or added to cause foaming of the polyurethane as it is formed. Generally, trace amounts up to about 0.5 parts by weight of water based on the weight of the total reaction mixture will be effective, and for foaming, from about 0.1 to about 0.5 part by weight

on weight of total reaction mixture. The water is also believed to introduce urea linkages in the reaction product.

The diisocyanates used in the present invention include both aliphatic and aromatic types and mixtures thereof although the aliphatics are preferred. Representative members are tetramethylene diisocyanate, hexamethylene diisocyanate, trimethyl- hexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate, diethylbenzene diisocyanate, decamethylene 1,10-diisocyanate, cyclohexylene 1,2- diisocyanate and cyclohexylene 1,4-diisocyanate, and aromatic isocyanates such as 2,4- and 2,6-tolylene diisocyanate.

An especially preferred isocyanate is methylene di(cyclohexyl isocyanate). Somewhat less preferred diisocyanates are trimethyl hexamethylene diisocyanate and isophorone diisocyanate.

Other compounds which are useful are the isocyanate equivalents which produce the urethane linkages such as nitrile carbonate, that is, the adiponitrile carbonate of the formula:

The polyoxyethylene glycols are known entties which are readily available from chemical suppliers. Exemplarly commercial products manufactured by the union Carbide Corporation, New York, New York 10017, are (CARBOWAX^● 1450) and (CARBOWAX^● 8000) in which the numbers refer to average molecular weights.

The polyoxytetramethylene glycols are dihydric alcohols as represented by the formula HO(CH₂CH₂CH₂CH₂O)_nH where n is an integer of from about 9 to about 40. They are sold by E.I. DuPont de Nemours & Co., Delaware under the trademark and designation TERATHANE. For TERATHANE 1000, n=14 and for TERATHANE 2000, n=27. These are a blend of linear diols, in which the terminal OH groups are separated by repeating tetrantethylene ether groups.

In making the polyurethane polymer of the invention, the glycol components are formed into a homogeneous mixture which is then reacted with the diisocyanate. The reaction is catalyzed by known catalysts for such reaction, suitable ones being tin salts

and organic tin esters such as dibutyl tin dilaurate, tertiary amines such as triethyl diamine (DABCD) , N,N,N',N'-tetramethyl-1,3-butane diamine and other recognized catalysts for urethane polymer synthesis.

The polymer of the invention absorbs water in aqueous media accompanied by varying degrees of swelling depending on the particular polymer composition. Water absorption is determined by immersing the polymer in water at 20°C for 24 hours and weighing the polymer in the dry state and after removal from the water, and expressing the gain as % (by weight of polymer) of water absorbed.

The hydrophilic polyurethane polymer of the present invention is dimensionally stable upon repeated exposure to water and exhibits high mechanical strength, especially in the wet stage. These characteristics translate into superior film products made from the polymer such as, for example, condoms and gloves. Other uses include coatings, molding compounds, absorbents, carrier systems for active agents including a nonleachable carrier system, a leachable carrier system, and wherein the carrier system is disposed in liquid medium, e.g. a body fluid, or in a gaseous medium such as air, ion exchange resins, and such manufactured articles as dialysis membranes, dentures, cannulae, e.g. feeding tubes, contact lenses, packaging components, burn dressings, contraceptive devices, sutures, surgical

implants, blood oxygenators, intrauterine devices, vascular prostheses, oral delivery systems, battery separator plates, eye bandages, corneal prostheses, antifog coatings, surgical drapes, oxygen exchange membranes, artificial fingernails, finger cots, adhesives, gas permeable membranes, and protective and drag resistant coatings.

The invention is further illustrated by the following examples, in which the components are in parts by weight unless stated otherwise.

Polymer Preparation Prior Art Hydrophilic Polyurethane

A mixture of 42.3 parts of CARBOWAX 8000, 17.0 parts of CARBOWAX 1450, 9.1 parts of diethylene glycol and 0.3 parts of water were heated to about 70°C with stirring until a homogeneous melt was obtained. While continuing the stirring, there was added 24.1 parts of methylene bis-(cyclohexyl)-4,4-isocyanate (a product sold as DESMODUR^● W by the Mobay Chemical Corporation, Penn Lincoln Parkway West, Pittsburgh, Pennsylvania 15205) during which the temperature decreased. When the temperature reached about 50°C, there was added 0.15 ml of stannous octoate, and the mass allowed to exotherm to about 70°C. The mass was then poured into a polypropylene pan. During pouring.

the temperature continued to rise to about 80°C and the mass foamed. Upon finishing of the pouring operation, the pan was placed in an oven and he l d at 100 °C for about one hour to complete formation of the polymer.

EXAMPLE 1

The procedure aforesaid was repeated except that 20% of the diethylene glycol was substituted on an equivalent basis with TERATHANE 2000 , a polytetramethylene ether glycol having an average molecular weight of 2000 and sold by the E. I. DuPont de Nemours & Company, Wilmington, Delaware. This results in the following composition :

31.8 parts of CARBOWAX 8000

12.8 parts of CARBOWAX 1450 5.4 parts of diethylene glycol

0.3 parts of water

25.7 parts of TERATHANE 2000

24.1 parts of DESMODUR W.

The following properties of the two polymers were measured in the fully swollen state:

Polymer Substituted Nonsubstituted

Water Absorption (%) 47.7 60.7 Tensile Strength (psi)* 2,120 890 100% Modulus (psi) 200 400 Ultimate Elongation (%) 525 295 Tear Strength (lb/in) 82 58

*Measured according to ASTM Method D-412

EXAMPLE 2

A mixture of 48.8 parts of CARBOWAX 1450, 7.3 parts of ethylene glycol, 0.3 parts of water and 43.6 parts of DESMODUR W were reacted following the procedure of Example 1. The reaction was repeated except that 10% on an equivalent basis of the ethylene glycol was substituted with TERATHANE 2000. This composition had the following components:

38.8 parts of CARBOWAX 1450 5.2 parts of ethylene glycol 20.8 parts of TERATHANE 2000

0.2 parts of water

35.1 parts of DESMODUR W.

The following properties of the polymers were measured:

Polymer Substituted Nonsubstituted

Water Absorption (%) 38.7 45.1

Mechanical Properties, Dry/Wet Tensile Strength (psi) 3418/2380 2250/1920 100% Modulus (psi) 455/601 1430/1180 Ultimate Elongation (%) 500/500 424/520 Tear Strength (lb/in) 222/220 165/66

The substituted polymer of Examples 1 and 2 is much more soluble in lower alcohols, which is an advantage for dipping manufacturing procedures, and is soft and pliable in its dry state, while the nonsubsti- tuted, prior art polymer is tough and parchmentlike.

Both of the polymers from Example 1 and Example 2 are especially suitable for preparation of condoms, diaphragms, electronic and surgical gloves and similar products, where high tensile and tear strength in both dry and wet state is essential.

EXAMPLE 3

A typical prior art hydrophilic polyurethane was prepared by reacting 27.5 parts of CARBOWAX 1450, 19.1 parts of diethylene glycol, 0.1 parts of water, and 53.4 parts of DESMODUR W by the procedure as previously described.

Then, a part of the soft segments (CARBOWAX 1450) was substituted on an equivalent basis by TERATHANE 1000 in increments of 20, 50 and 80 weight percent. Such substitution decreases the water absorption markedly. However, the mechanical properties are substantially improved as shown in the following table:

Nonsub- substituted

Polymer stituted 20% 50% 80%

Water Absorption (%) 30.2 25.0 9.8 2.8

Tensile Strength

(psi) Dry/Wet 4770/2040 4314/3420 4257/3909 6750/4650

Tear Strength

(lb/in) Dry/Wet 598/374 887/368 577/513 648/724

The 20% substituted polymer of this group has the following composition: 22.4 parts of CARBOWAX

1450, 19.4 parts of diethylene glycol, 3.9 parts of TERATHANE 1000, 0.1 part water and 54.3 parts of DESMODUR W. The 50% and 80% substituted polymer contains equivalent parts of components.

EXAMPLE 4

Another specimen of the prior art hydrophilic polymer was prepared following the procedure of Example 3 but modified by substituting on an equivalent basis 20%, 50%, and 80% of the hard segments (diethylene glycol) with the TERATHANE 1000. The 20% substituted polymer of this group consists of: 20.8 parts of CARBOWAX 1450, 11.5 parts of diethylene glycol, 27.2 parts of TERATHANE 1000, 0.1 part water and 40.4 parts of DESMODUR W. The 50% and 80% substitution are based on the 20% formulation. A comparison of the properties of the nonsubstituted and substituted polymers are set forth below:

flonsub- Substituted

Polymer stituted 20% 50% 80 %

Water Absorption (%) 30.2 30.1 20.0 18.0

Tensile Strength

(psi) Dry/Wet 4770/2040 3180/1293 N/A* 30/312 Tear Strength

(lb/in) Dry/Wet 598/374 170/159 N/A* 21/73

*Sample too sticky to be measurable

As will be observed, excessive substitution of the hard segments with the specific polyoxytetramethylene glycol of the example lead to a reduction in tensile and tear strength. Of course, by selecting reactants of other molecular weights and/or by varying the reactant ratios in accordance with the invention, the properties can be improved.

EXAMPLE 5

A mixture of 22.5 parts of CARBOWAX 1450, 4.9 parts of ethylene glycol, 39.3 parts of TERATHANE 2000, 0.2 parts of water and 33.1 parts of DESMODUR W were reacted as described in Example 1. The test data below

demonstrates the excellent mechanical properties of the polymer:

Water Absorption (%) 21.7

Mechanical Properties (Dry/Wet)

Tensile Strength (psi) 3866/2493

100% Modulus (psi) 456/430

Ultimate Elongation (%) 600/625

Tear Strength (lb/in) 232/283

Polymer Applications

EXAMPLE A - Denture Liner

The polymer from Example 2 was placed in a Carver press at 104.4 °C to 115.5°C and 3,000 pounds pressure and formed into a sheet 1-1.2 mm thick. The po lymer plate was coated on one si de with a layer of GELVA" RA 788 adhesive (vinylacetate acrylic multpolymer adhesive, Monsanto, St. Louis, MO) using a doctor blade.

Following the drying of the adhesive layer, the soft polymeric sheet was adapted to the gum-contacting surface of a full upper denture, pressed into place and the excess cut off with a scalpel.

After swelling in water, the polymer further softens and owing to its water content, exhibits water spreading on its surface. Thus, the advantage of this type of denture liner is two-fold: the soft layer cushions the denture and prevents erosion of the gums, and the hydrophilic surface increases the adhesion.

EXAMPLE B - Wound Dressing

The polymer from Example 1 was dissolved in chloroform as a 10% solids solution, and a film 3 mil thick was cast on release paper. When the last remnants of the solvent evaporated, a polyurethane/ polyacrylic hydrophilic adhesive (Tyndale Plains-Hunter

Ltd., Ringoes, NJ) was spread on top of the polymeric film, using a doctor blade.

The finished film when used as a wound dressing composite has a Moisture Vapor transmission Rate of 1,250 g/m²/24 hours and oxygen permeability of 13 g O₂/m²/24 hours.

EXAMPLE C - Transdermal Patch

A film was prepared as in Example B, but to the solution was added 10% of indomethacin (1-(p- chlorobenzoyl)-5-methoxy-2-methyl-3-indolylaceticacid)

--an anti-inflammatory and analgesic-- based on the weight of the polymer used.

The cast films with the hydrophilic adhesive was tested as a transdermal patch. On rats, the film was found to release indomethacin at a rate of 6 g/cm²/24 hours.

EXAMPLE D - Leachable Carrier

A film was cast from the polymer of Example 1, using a formulation containing 10% by weight of polymer and 1% sodium bicarbonate in a solvent blend of 60 parts ethyl alcohol, 10 parts isopropyl alcohol and 20 parts water. After the film was dried to constant weight, it was eluted in distilled water at 25°C. The elution rate of the sodium bicarbonate from the film was found to be 280 mg/10 hours.

EXAMPLE E - Control led Antibiotic Release

A 10% solution of the polymer from Example 1 was prepared in chloroform. Commercial tablets of antibiotic were coated with the polymer solution. Ninety-eight percent (98%) of the drug present, that is, 0.98 g, eluted at 37 °C in distilled water in 15 hours.

EXAMPLE F - Controlled Analgesic Release

Commercial aspirin tablets (325 mg/tablet, product of Bayer Company, division of Sterling Drugs, Inc., New York, NY) was coated with the 10% solution of polymer from Example 1 in chloroform.

At 25°C, the elution rate in distilled water was 290 mg/20 hours. This experiment was repeated with the ground tablets placed in capsules, prepared from the above-mentioned polymer solution by dipping on a Teflon● mandrel. The elution rate was slightly slower, about 250 mg/20 hours.

EXAMPLE G - Veterinary DruG Delivery

Triple-Sulfa Boluses, a veterinary product of

Pfizer Agricultural Division, New York, NY, containing 90 grains sulfamethazine, 90 grains sulfanilamide and 60 grains sulfathiazole each in 824 mg of electrolyte salts, were coated with a solution of 10% solids of the polymer from Example 2 in 90% ethyl alcohol.

While the uncoated boluses dissolve almost immediately, the coated boluses eluted 100% of the

active ingredients at 39 °C in sa l ine over a per iod of 6 days.

EXAMPLE H - Insecticide Del ivery

Seventy (70) parts of the polymer from Example 2 were dissolved with 16 parts of Baythroid" FCR 1272 (Cyano (4-fluoro-3-Sphenoxyphenyl)methyl-3- (2 ,2- dichloroethenyl) -2 ,2-dimethyl-cyclo-propanecarboxylate) , manufactured by Bayer, Leverkusen, FRG, in 350 parts of methyl alcohol. The solution was sprayed on 475 parts of ground corn cobs and l eft to dry thoroughly.

The coated granules were spread outdoors, using a spreader delivering 15.4 lbs/acre. The area, which was originally infested with ticks was completely free of ticks for a period of four weeks, despite heavy rainfall and high temperatures.

Control spreading, using only the insecticide on the granules (no polymer) in the same concentration, was effective only for 24 hours in controlling the tick population.

EXAMPLE I - Antifogging Agent

A solution was prepared from 4 parts of the polymer from Example 2, 0.09 parts of a leveling agent Silwet" L-7604 organosilicone fluid, manufactured by Union Carbide Silicones Division, Danbury, CT), 90 parts of ethyl alcohol and 5 parts of water.

The solution was weighed into aerosol cans. After capping with the valve and dip tube assembly, the can were filled with DYMEL^● 22 (fluorocarbon propellant, manufactured by E.I. DuPont and de Nemours, Wilmington, Delaware) in a ratio of 40 parts solution, 25 parts propellant.

Glass plates and mirrors were sprayed with this solution. The dried film prevents fogging of such coated objects, and will withstand several 15 minute cylces in the fog chamber without fogging.

The samesolution may also be used for saturating nonwoven pads, packaged in foil envelopes to prevent a loss of solvent.

EXAMPLE J - Coated Catheter

A latex Foley urinary catheter was dip-coated with a solution made from 3 parts of polymer from

Example 1 and 97 parts of dichloroethane. After air drying, the dipping was repeated. The coating was cured at 80°C for 5 minutes.

While the uncoated latex has a coefficient of friction of 0.4 (as measured according to ASTM D-1894- 75), the coated catheter has a coefficient of friction in fully hydrated state of 0.18.

EXAMPLE K - Cosmetic Film

A solution prepared from 7 parts of polymer from Example 1, 88 parts of 200 proof SDA ethyl alcohol and 5 parts of water was used as a wrinkle patch. When applied to the skin in the area of wrinkles, it dries to an invisible, nonshiny film, which partially fills and masks the wrinkles. Makeup or blush can be applied directly on the polymeric film. The film is removed by applying water and stripping, usually. in one piece.

EXAMPLE L - Deodorant Delivery

A solution prepared from 4 parts of polymer from Example 2, 0.2 parts of a suitable fragrance, 88 parts of SDA 200 proof alcohol and 5 parts of water was placed into aerosol cans. The cans were capped with the valve assemblies and filled with 25 parts of DYMEL 22 propellant to 30 parts of solution.

The resulting spray was used as a deodorant. When sprayed on skin, the films prevent moisture transport in the liquid form, but does not prevent moisture vapor transmission. Thus, the subject remains "dry", with no visible sweat formation on the skin. Moreover, the hydrated film releases slowly the fragrance over a period of several hours.

EXAMPLE M - Intravenous Feeding Catheter

The polymer of Example 2 was cut into thin strips and fed into a 1 inch Killian vented extruder and continuously extruded. The extrusion conditions were set as follows:

Zone 1: 265°F

Zone 2: 380°F

Zone 3: 275°F

Die: Off

Speed: 18 rpm

Pressure: Very low --did not register on gauge

Amps: 3-5

The die was selected to give a thin-wall tubing of French 2 size.

EXAMPLE N - Body Implant

The extrusion conditions of Example M were repeated except that a die was elected to give a rod having a diameter of 3.5 mm. The rod can be used as an implantable storage device for both human and veterinary drugs.

Claims

Claims:

1. A hydrophilic, thermoplastic polyurethane polymer, of improved dimensional stability and mechanical strength , said polymer having an average molecular weight of from about 10 ,000 to about 200 ,000 and comprising the reaction product of :

A. a mixture of alkylene glycols comprising

(i) ethylene glycol and/or diethylene glycol ,

(ii) a polyoxyethylene glycol having an average molecular weight of from about 400 to about 20 ,000, and

(iii) a polyoxytetramethylene glycol having an average molecular weight of from about 650 to about 2900;

B. an organic diisocyanate, the ratio of NCO to OH being from about 1 to slightly less than 1 ; and

C. a minor amount of water.

2. The polyurethane polymer of claim 1 wherein the mixture of alkylene glycols comprises

(i) from about 2 parts to about 15 parts by weight of ethylene glycol and/or diethylene glycol,

(ii) from about 10 to about 80 parts by weight of polyoxyethylene glycol and

(iii) from about 10 to about 60 parts by weight of polyoxytetramethylene glycol, and the water content is from about 0.1 part to about 0.5 part, based on the total weight of A, B and C.

3. The polyurethane polymer of claim 1 wherein the mixture of alkylene glycols reacted with the diisocyanate comprises

(i) from about 4 to about 10 partε of ethylene glycol and/ or diethylene glycol ,

(ii) from about 22 parts to about 59 partε of polyoxyethylene glycol and

(iii) from about 20 to about 40 partε of polyoxytetramethylene glycol and the water content is from about 0.1 part to about 0.5 parts, based on the total weight of A, B and C.

4. The polyurethane polymer of claim 1 wherein the diisocyanate is an aliphatic diisocyanate selected from methylene bis(cyclohexyl)-4,4'- isocyanate, trimethyl hexamethylene diisocyanate, isophorone diisocyanate and cyclohexyl diisocyanate.

5. The polyurethane polymer of claim 4 wherein the diisocyanate is methylene bis(cyclohexyl)- 4,4'-isocyanate.

6. The polyurethane polymer of claim 5 wherein the polyoxytetramethylene glycol has an average molecular weight of from about 1000 to about 2000.

7. A carrier system comprising an active agent and as a carrier vehicle therefor, a hydrophilic, thermoplastic polyurethane polymer of improved dimensional stability and mechanical strength, said polymer having an average molecular weight of from about 10,000 to about 200,000 and comprising the reaction product of:

A. a mixture of alkylene glycols comprising

(i) ethylene glycol and/or diethylene glycol,

(ii) a polyoxyethylene glycol having an average molecular weight of from about 400 to about 20 ,000 , and

(iii) a polyoxytetramethylene glycol having an average molecular weight of from about 650 to about 2900 ;

B. an organic diisocyanate, the ratio of NCO to OH being from about 1 to s light ly less than

1 ; and

C. a minor amount of water.

8. The carrier system as defined in claim 7 wherein the mixture of alkylene glycols comprises

(i) from about 4 to about 10 parts by weight of ethylene glycol and/or diethylene glycol,

(ii) from about 22 parts to about 59 parts by weight of polyoxyethylene glycol and

(iii) from about 20 to about 40 parts by weight of polyoxytetramethylene glycol, and the water content is from about 0.1 part to about 0.5 part, based on the total weight of A, B and C.

9. The carrier system of claim 7 wherein the same is a nonleachable carrier system.

10. The carrier system of claim 7 wherein the same is a leachable medium system.

11. The carrier system of claim 10 wherein the leachable carrier system is an aqueous medium, leachable carrier system.

12. The carrier system of claim 11 wherein the carrier system is disposed in a liquid medium.

13. The carrier system of claim 12 wherein the liquid medium is a body fluid.

14. The carrier system of claim 7 wherein the carrier system is disposed in a gaseous medium.

15. The carrier system of claim 14 wherein the gaseous medium is air.

16. The carrier system of claim 7 wherein the polymer carrying the active agent is in the shape of a film.

17. The carrier system of claim 7 wherein the polymer carrying the active agent is in the shape of a rod.

18. A bodily implant comprising the rodshaped polymer of claim 17 and wherein the active agent is leachable in contact with bodily fluids.

19. The carrier system of claim 7 wherein the active agent is a drug for human or veterinary use.

20. The carrier system of claim 16 wherein the film is a wound or burn dressing.

21. The carrier system of claim 16 wherein the active agent is a fragrance.

22. The carrier system of claim 16 wherein the active agent is a deodorant or antiperspirant.

23. A water absorbent coating comprising a hydrophilic, thermoplastic polyurethane polymer of improved dimensional stability and mechanical strength, said polymer having an average molecular weight of from about 10 ,000 to about 200 ,000 and comprising the reaction product of :

A. a mixture of alkylene glycols comprising

(i) ethylene glycol and/or diethylene glycol,

B. an organic diisocyanate, the ratio of NCO to OH being from about 1 to s lightly less than 1 ; and

C. a minor amount of water.

24. A low friction, water absorbent coating comprising a hydrophilic, thermoplastic polyurethane polymer of improved dimensional stability and mechanical strength, said polymer having an average molecular weight of from about 10,000 to about 200,000 and comprising the reaction product of:

A. a mixture of alkylene glycols consisting of (i) ethylene glycol and/or diethylene glycol, (ii) a polyoxyethylene glycol having an average molecular weight of from about 400 to about 20,000, and (iii) a polyoxytetramethylene glycol having an average molecular weight of from about 650 to about 2900;

B. an organic diisocyanate, the ratio of NCO to OH being from about 1 to slightly less than 1; and

C. a minor amount of water .

25. The coating of claim 23 wherein the same is an antifogging coating.

26. The coating of claim 23 wherein the same is adapted for application to a boat hull for reduced friction flow.

27. The coating of claim 23 wherein the same is adapted for application to the inside of a duct for reduced friction flow.

28. The coating of claim 23 wherein the same is adapted for application to a medical device.

29. The coating of claim 28 wherein the medical device is a body implant.

30. The coating of claim 28 wherein the medical device is a cannula.

31. The coating of claim 28 wherein the medical device is a catheter.

32. As an article of manufacture, a shaped, three-dimentional structure formed of a hydrophilic, thermoplastic polyurethane polymer having an average molecular weight of from about 10 ,000 to about 200 ,000 , said polymer comprising the reaction product of :

A. a mixture of alkylene glycols comprising

(i) ethylene glycol and/or diethylene glycol,

(ii) a polyoxyethylene glycol having an average molecular weight of from about 400 to about 20,000, and

C. a minor amount of water.

33. The article of manufacture as defined in claim 32 wherein the structure is a film.

34. The article of manufacture as defined in claim 33 wherein the film is in the form of a glove.

35. The article of manufacture as defined in claim 33 wherein the film is in the form of a denture liner.

36. The article of manufacture as defined in claim 33 wherein the film is in the form of a condom.

37. A film forming cosmetic composition for application as a wrinkle patch comprising a solution of the polymer of claim 1 in an evaporable solvent.

38. A deodorant delivery system for applying an odor-controlling, moisture vapor permeable, but water impermeable, film to the skin, comprising a film-forming solution of the polymer of claim 1 in an evaporative solvent, and means for delivering the film-forming solution to the desired skin area.

39. The deodorant delivery system as defined in claim 38 wherein the delivery means is an aerosol vessel.

40. The article of manufacture as defined in claim 32 wherein the structure is a contact lens.

41. The article of manufacture as defined in claim 32 wherein the structure is an extruded shape.

42. The article of manufacture as defined in claim 32 wherein the structure is a tube.

43. The article of manufacture as defined in claim 32 wherein the structure is in the form of a bead.

44. The article of manufacture as defined in claim 42 wherein the structure is an intravenous catheter.

45. The article of manufacture as defined in claim 42 wherein the structure is a cannula.

46. The article of manufacture as defined in claim 45 wherein the cannula is a feeding tube.

47. The article of manufacture as defined in claim 32 wherein the structure is an intrauterine device.

48. The article of manufacture as defined in claim 32 wherein the structure is a body implant.