AU642409B2 - Linear polyurethane elastomer compositions and use of modified diisocyanates for preparing same - Google Patents

Description

OPI DATE 22/10/90 APPLN. ID 53551 pC-T AOJP DATE 29/11/90 PCT NUMBER PCT/US90/01477 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 5 (11) interrianal Publication Number: WO 90/11309 CO8G 18/10, 18/44, 18/48 Al (43) International Publication Date: 4 October 1990 (04.10.90) (21) International Application Number: PCT/US90/01477 (81) Designated States: AT (European patent), AU. BE (European patent), BR, CA, CH (European patent), DE (Eu- (22) International Filing Date: 19 March 1990 (19.03.90) ropean patent), DK (European patent), ES (European patent), FI, FR (European patent), GB (European pa.

tent), IT (European patent), JP, KR, LU (European pa- Prio, y date' tent), NL (European patent), NO, SE (European patent).

326,183 20 March 1989 (20.03.89) US 326,865 20 March 1989 (20,03.89) US Published With international search report.

(71) Applicant: REEVES BROTHERS, INC. [US/US]; High. Before the expiration of the time limit for amending the way 29 South, Spartanburg, SC 29304 claims and to be republished in the event of the receipt of amendments.

(72) Inventors: ROCS, Bert, A. 91 Woodwind Drive, Spartanburg. SC -)302 DAMEWOOD, John, R. 116 Hollyridge Road, Spartanburg. SC 29301 (US), (74) Agent: LAWRENCE, Stanton, Ill; Pennie Edmonds.

1155 Avenue of the Americas, New York, NY 10036 6 4 1.

(US),

(54)Title: LINEAR POLYURETHANE ELASTOMER COMPOSITIONS AND USE OF MODIFIED DIISOCYANATES FOR PREPARING SAME (57) Abstract Linear polyurethane elastomers of a polyol component, at least two extender components, and a diisocyanate compound are prepared by reacting the diisocyanate compound with one of the extender components to form a modified diisocyanate component having a functionality of about 2 prior to reacting this modified component with the other components of the elastomer. A preferred polyol component includes a mixture of a polycarbonate polyol and a polyether polyol. These new elastomers possess a unique combination of hydrolytic stability, toughners, and flexibility and can be processed at lower temperatures compared to elastomers prepared from similar compositions wherein the isocyanate compound is not modified.

-I See back of page WO 90rM 1309 PCT/US90/01477 -1- LINEAR POLYURETRANE ELASTOMER COMPOSITIONS AND USE OF MODIFIED DIISOCYANATES FOR PREPARING SAME Technical Field The present invention relates to the preparation of linear thermoplastic polyurethane elastomer3 of a polyol component, at least one extender component, and a diisocyanate compound by initially reacting the diisocyanate compound with the extender to form a modified diisocyanate component prior to reacting this component with the polyol component and other extenders, if any.

Background Art In today's market, polyurethane elastomers are utilized in a wide array of products and applications, including producing industrial coated fabrics. For the latter, these polyurethanes are generally linear polymers exhibiting elastomeric characteristics of high tensile strength and elongation.

These linear polyurethanes are quite varied in their final properties as a result of the large number of permutations that can be applied to the three main components that are used in their manufacture. These components are polyols, polyisocyanates, and one or more extenders (generally diols). Some examples of these compounds are: polyether, polyester, polycaprolactone, polycarbonate, and polybutadiene polyols; toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, naphthalene diisocyanate; xylene diisocyanate, hexane diisocyanate, and hydrogenated 4,4'-diphenylmethane diisocyanate; and 1,4butanediol, 1,6-hexanediol, and 1,3-butanediol extenders.

Typically, polyurethane elastomers which are considered top of the line with respect to performance, include, for example, polytetramethylene glycol (polyether) polyurethanes and poly(butane adipates or hexane adipates) ester WO 90/11309 PCT/US90/01477 polyurethanes. Of these polymers, the polyether polyursthbnes exhibit good hydrolytic stability and low temperature properties but are generally poor for fuel resistance and oxidation resistance, while the polyester polyurethanes are tough with good abrasion resistance, oxidation resistance and fuel resistance, but not particularly resistant to hydrolysis. Still, at the present time the polyesters are generally considered to represent the best compromise of physical properties and chemical resistance of the various polyurethanes.

There are also a few polyurethanes based on polycarbonate polyols in the market. It is well known that these polycarbonate polyurethanes have very good hydrolytic stability and generally have good to very good resistance to other degradation forces; however, they ars usually too hard, rigid and brittle for use in industrial coated fabrics.

Currently, high performance coated fabrics are based on polyester polyurethanes in order to meet the specifications currently in effect, but resistance to hydrolysis remains their weak point and represents a problem for these products. Thus, there is a desire for improved hydrolytic stability in a number of applications. A polyurethane having improved hydrolytic properties and sufficient elastomeric character to be useful in the manufacturing of industrial coated fabrics is also des3rable and needed.

It is known from Japanese Patent Specification Sho(61)-76275 that polyurethane elastomers can be produced from a diol mixture of a polycarbonate diol and a polyoxytetramethylene glycol, and/or a polydimethyl siloxane glycol; an organic diisocyanate and a chain extension compound. Practical Example 4 of Table I lists a porous polyurethane film formed from an 80/20 mixture of polycarbonate diol and polyoxytetra methylene glycol; 4,4'diphenyl methane diisocyanate and 1,4-butylene glycol, while Practical Example 1 illustrates a film formed from a WO 90/11309 PCUS90/01477 -3- 50/25/25 mixture of polycarbonate diol/polyoxytetra methylene glycol/polydimethylsiloxane glycol; 4,4'-diphenyl methane diisocyanate and ethylene glycol. These porous films can be used in the manufacture of artificial leather or suede articles.

Also, Japanese Patent Specification Sho(61)-151235 discloses the preparation of aliphatic polycarbonate polyols from various mixtures of dialkyl carbonates and glycols.

These polyols are described as having low color adhesion and smooth reactivity with isocyanates. Neither reference suggests that these materials can be used as or in the production of polyurethane elastomers for industrial coated fabrics.

A wide variety of organic isocyanate and polyisocyanate compounds are available for use in the preparation of polyurethane elastomers. The particular isocyanate is selected to facilitate preparation of the polyurethane for the intended application. Generally, isocyanates which are liquid at room temperature are prepared for ease of handling.

Diphenyl methane diisocyanate is a solid diisocyanate which is available on a commercial scale and consists primarily of the 4,4' isomer with a small amount of the 2,4' isomer. These isomers are both solids at room temperature, having melting points of 42 and 36'C, respectively. Other isomers, such as the 2,2' isomer, are also solid at room temperature.

To convert solid MDI into a form which is more desirable for use in the preparation of polyurethanes, the prior art teaches that a liquid MDI composition can be prepared, fe'r example, by partially reacting solid MDI with a glycol, diol or other polyol. Generally, about 10 to of the isocyanate groups are reacted with the polyol. A number of U.S. patents illustrate this concept, including U.S. Patents 3,883,571, 4,115,429, 4,118,411, 4,229,347, 4,490,300, 4,490,301, 4,539,156, 4,539,157 and 4,539,158.

Such liquid diisocyanates are stated as being useful for forming polyurethanes for a wide variety of applications.

None of these modified disocyanate compositions have, however, been utilized to prepare linear thermoplastic polyurethane elastomers which have lower temperature processing characteristics compared to similar compositions prepared from solid MDI.

SUMMARY OF THE INVENTION According to the present invention, there is provided a process for the preparation of a linear thermoplastic polyurethane elastomer composition from a polyol component, a diisocyanate compound, and a first extender component having a molecular weight of less than 500, said process including the step of lowering the processing temperature of said polyurethane by reacting the diisocyanate compound with said first extender in a molar ratio of above 2:1 to form a modified diisocyanate component having a functionality of about 2 prior to reacting the modified diisoeyanate component with the polyol component, thus forming a linear thermoplastic polyurethane elastomer composition having lower temperature processing characteristics compared to similar compositions wherein the diisocyanate compound is not modified.

The present invention further provides a linear thermoplastic polyurethane elastomer composition including: a polyol; a diisocyanate compound, and a first extender component having a molecular weight of less than 500; wherein the diisocyanate compound is initially reacted with the first extender component in a molar ratio of above 2:1 so as to form a modified diisocyanate component having a functionality of about 2 prior to reaction with the polyol components to provide lower temperature processing characteristics compared to similar compositions wherein the diisocyanate is not modified.

4 The present invention also provides a linear thermoplastic polyurethane elastomer composition including: a polycarbonate polyol; a polyether polyol; a diisocyanate compound; a first extender component having a molecular weight of less than 500; and a second extender component; wherein the diisocyanate compound is initially reacted with one of the extender components in a molar ratio of above 2:1 so as to form a modified diisocyanate component having a functionality of about 2 prior to reaction with the other components to provide relatively low temperature processing properties to the composition, whereas the polyol components provide superior hydrolytic stability and low temperature flexibility properties to the composition.

The polyol component may be a polyether polyol, polycarbonate polyol, polycaprolactone polyol, polyester polyol, polybutadiene polyol or mixtures thereof, and the first extender component is preferably a polyol or amine compound having a molecular weight of less than about 500. Preferably the first extender component comprises a diol. Also, the second extender component is preferably included for optimum results.

Generally, between about 10 to 30% by weight of the diisocyanate compound is modified so that the modified diisocyanate component has an NCO content of between about bo 4a 4 v

.F

WO 90/11309 PCT/US90/01477 14 and 33%, and preferably between about 20 and 26%. The most advantageous diisocyanate compound is one that primarily comprises 4,4'-diphenyl methane diisocyanate, with the first extender component being a polyol or amine compound having a molecular weight between about 60 and 250, such as 1,4-butane diol, tripropylene glycol, dipropylene glycol, propylene glycol, ethylene glycol, 1,6-hexane diol, 1,3-butane diol, neopentyl glycol, ethylene diamine or mixtures thereof.

The present invention also relates to a linear n\ thermoplastic polyurethane elastomer compositions comprising a mixture of a polycarbonate polyol and a polyether polyol; a diisocyanate compound; and first and second extenders.

The diisocyanate compound is initially reacted with one of the extenders in a molar ratio of above 2:1 so as to form a modified diisocyanate component having a functionality of about 2 prior to reaction with the other components. This modified diisocyanate component provides relatively low temperature processing properties to the composition, whereas the polyol mixture provides superior hydrolytic stability and low temperature flexibility to the composition.

Preferably, the first extender component is a polyol or amine compound having a molecular weight of less than about 500, such as a diol, while the diisocyanate compound primarily comprises 4,4'-diphenyl methane diisocyanate.

Advantageously, the first extender component is a polyol or amine compound having a molecular weight between about and 250, such as 1,4-butane diol, tripropylene glycol, dipropylene glycol, propylene glycol, ethylene glycol, 1,6hexane diol, 1,3-butane diol, neopentyl glycol, ethylene diamine or mixtures thereof.

Generally, the polyether polyol and polycarbonate polyol are present in a relative amount of between 2:1 to 1:8. When the first extender is 1,4-butanediol and the WO 90/11309 PCT/US90/01477 -6second extender is tripropylene glycol, and when between about 10 to 30% by weight of the diisocyanate compound is modified, the modified diisocyanate component has an NCO content of between about 14 and 33%, preferably between about 20 and 26%. After modifying the diisocyanate, the modified mterial is reacted with the other components. The overall NCO/OH ratio of the entire composition is between about 0.95 and 1.05/1.

Detailed Description of the Invention One preferred embodiment of this invention relates to a polyurethane elastomer based on a mixture of polycarbonate and polyether polyols, a modified diisocyanate component formed by reacting a diisocyanate compound with a low molecular weight extender such as tripropylene glycol, and a second extender of 1,4-butanediol. The modified diisocyanate and the second extender enable the polymer to have low temperature processing properties compared to those wherein the diisocyanate is not modified. This polymer also has hydrolytic stability which is vastly superior to conven'tional polyester polyurethanes. This polymer also has elastomeric characteristics and other physical properties which render it suitable for use in coated fabric manufacturing processes and resultant products produced therefrom.

In this embodiment, the polyether polyol and polycarbonate polyol can be used in any relative amounts provided that each are present in the composition. It has been found convenient to use a polyether polyol: polycarbonate polyol ratio in the range of between 2:1 to 1:8.

Instead of tripropylene glycol and 1,4-butanediol, other low molecular weight extenders can be used.

Generally, polyols having a molecular weight of between about 60 and 500 (and preferably less than 250) have been WO 90/11309 PCT/US90/01477 -7found to be advantageous, although amines such as ethylene diamine can also be used. Specific polyols include diols such as 1,3-butanediol, ethylene glycol, tripropylene glycol, dipropylene glycol, propylene glycol, and neopentyl glycol, triols such as trimethyol propane, as well as mixtures of these components, can be used.

Any diisocyanate compound is suitable with those based on 4,4'-diphenyl methane diisocyanate being preferred.

Toulene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, xylene diisocyanate and cyclohexane diisocyanate can also be used, if desired, but these compounds are generally more expensive or slower reacting.

Such diisocyanate compounds are converted to a modified diisocyanate component as previously described.

The relative amount of modified diisocyanate to polyol ranges from above 2:1 to 20:1, and preferably between about 2.5:1 and 8:1. The second extender compound is included in an amount to achieve a final NCO:OH ratio of between about 0.95 to 1.05/1. The Examples illustrate preferred ratios of components Zor use in the preparation of linear polyurethanes in accordance with this invention.

Another preferred embodiment of the invention relates to the manufacture of any type of polyurethane elastomer prepared from the modified diisocyanate component to significantly lower the temperature requirements for processing the polyurethane on heat processing equipment, calenders, extruders, injection molding apparatus, etc. This modification includes reacting diisocyanate compound with a low molecular weight extender polyol or amine compound, to form a modified diisocyanate component, prior to preparing the polyurethane with the other components.

The term will be used throughout this application to designate diisocyanate compounds primarily based on 4,4'-diphenyl methane diisocyanate which are preferred for use in this invention. Also, the term "liquid MDI" will be WO 90/11309 PCT/US90/01477 -8used to designate an essentially difunctional modified MDI component prepared from the reaction of a low molecular weight polyol with an MDI compound to form a modified diisocyanate composition which is liquid at room temperature.

The low molecular weight extender used to modify the diisocyanate compound generally includes diols, triols or amines having a molecular weight below about 500, but any polyol which enables the diisocyanate compound to possess a functionality of about 2 and an NCO content of between about 14 and 33%, preferably between 20 and 26%, after modification, would be acceptable.

In this embodiment, essentially any polyol component can be used for reaction with the liquid MDI component, including polyether, polyester, polycaprolactone, polycarbonate or polybutadiane polyols or mixtures thereof.

As noted above, a preferred polyol component is mixture of a polyether polyol and polycarbonate polyol.

It is also possible to add additional extenders to such compositions, these extenders also being a polyol or amine compound, preferably one of relatively low molecular weight less than about 500). It is also possible to utilize unsaturated polyols as extenders, such as low molecular weight diols which include one or more double bonds.

However, any conventional extender known to those skilled in the art can be used, depending upon the results desired.

Thus, the present invention demonstrates how various polycarbonate and polyether polyols, modified diisocyanate components and extenders may be blended over a wide range to allow the design of polyurethane polymers having different physical characteristics and properties. This makes it possible to custom design a polymer for a particular application.

There are several different types of modified MDIs presently on the market, but the types suitable for use in this invention are essentially difunctional. The preferred WO 90/111309 PCT/US9/01477 -9liquid MDI components are made by reacting an MDI compound with a small amount of a diol such as tripropylene glycol or a mixture of diols. The material resulting from this slight extension of the MDI compound is a liquid at room temperature while, as noted above, the original MDI compound is a solid at such temperatures. This makes the liquid MDI substantially easier to handle and process, while retaining generally equivalent performance to the unmodified MDI compound.

Representative modified liquid MDI components which are suitable and preferred for use in the present invention are disclosed in U.S. Patents 3,883,571, 4,115,429, 4,118,411, 4,229,347, 4,490,300, 4,490,301, 4,539,156, 4,539,157, and 4,539,158: all these components are essentially difunctional and are obtained as the reaction product of MDI. With a diol or polyol having a molecular weight below about 500. To the extent necessary to understand this component of the inventive compositions, these patents are expressly incorporated herein by reference thereto. Those isocyanates having a functionality which is much greater than two are not particularly suitable for use in this invention, since they promote crosslinking rather than linearity in the resultant polyurethane polymer. The functionality of these compounds should be above 1.9 but below 2.2, with the preferred modified diisocyanate components being those having a functionally of approximately 2 soas to facilitate the preparation of linear polyurethanes.

In the production of polyurethanes, it is generally known to utilize one of two different manufacturing processes. In one method, known as the "one-shot" approach, all hydroxyl bearing components polyols and extender diols) are combined as a mixture, to which is added an isocyanate component in essentially stoichiometric quantities to form the final product. The second method contemplates the formation of a prepolymer by reacting WO 90/11309 PCrT/LU390/01477 excess isocyanate with one or more high molecular weight hydroxyl bearing components, followed by the reaction of this prepolymer with the extender to form the final product.

As noted above, the use of the modified diisocyanate components of this invention enables a polyurethane having lower temperature processing characteristics to be achieved.

The temperature difference can be as great as 30 to below that of a corresponding formulation wherein the diisocyanate compound is not modified. However, greater temperature reductions are achieved when the polyurethane is manufactured in a specific manner.

For example, if the polyurethanes of the invention are made by the conventional "one shot" technique, a slight reduction on the order of about 3-4 degrees is obtained: this representing only about 10% of the maximum reduction which could be achieved. Similarly, if solid MDI is used to prepare an isocyanate prepolymer with the high molecular weight polyol prior to reacting this prepolymer with the mixed extenders, a temperature reduction of about degrees about 15% of the maximum) is achieved.

Substantial reductions in the temperature processability of the resulting polyurethane can be achieved by following one of the following methods of nanufacture.

In one version, the isocyanate is pre-reacted with one of the extenders to form a modified isocyanate component prior to reaction with a mixture of the high molecular weight polyol and other extenders. This enables a temperature reduction of about 20 to 25 degrees to be achieved about 60% of the optimum). Finally, the optimum temperature reduction is achieved by sequentially reacting the modified isocyanate component first with the high molecular weight polyol followed by reaction with the second extender. As noted above, a temperature reduction of 30 to 40 degrees is possible, with the formation of a clear polyurethane polymer.

WO 90/11309 PCT/US90/01477 -11- Again, MDI, modified as disclosed herein, is the most advantageous diisocyanate for use in preparing the polyurethanes of this invention, although the other isocyanates mentioned above can instead be used, if desired.

When light stability in a clear product is desired, an isophorone diisocyanate can be used to achieve better results than MDI. For a lower cost isocyanate component, toluene diisocyanate can be used, but it is less reactive than MDI. Thus, when TDI is used, amine extenders, rather than polyol or diol extenders, should be used. One skilled in the art can select the best combination of ingredients for any particular formulation.

These linear polyurethane elastomers are preferably made using a two step solution polymerization technique.

Prodried toluene, dimethyl formamide and the isocyanate are charged to a 3000 ml reactor (in some cases a 15,000 ml reactor was used). A given weight of polyol(s), the amount needed to achieve the desired prepolymer NCO/OH value, is dissolved in additional dry toluene. The reactor is then prepurged with dry nitrogen and maintained under a positive low pressure of dry nitrogen for the full reaction time.

The isocyanate containing solution is preheated to (depending on anticipated exotherm), and the solution of polyols is slowly added by a continuous stream (over one-half hour) to the reactor. The temperature is allowed to rise to 80-90'C (depending on system) and is maintained at this temperature for an additional two hours.

The desired extender diol is preweighed and dissolved in dry dimethyl formamide. The reactor is cooled to 60-65'C and two 7-10 gram samples of the reaction mixture are removed and analyzed for NCO content. The diol is then charged to the reactor, and the temperature raised (partly by the exotherm of extension) to 85-90'C and maintained at this temperature for two hours. A sample of the polymer is dried and an IR spectrum was run. If free NCO is detected in the spectrum, the reaction is continued for another hour.

WO 90/11309 PCT/US90/01477 -12- The reaction solution is then allowed to cool to room temperature overnight and stored in a container until it can be tested. All mixtures were designed to yield a solution of 30% by weight of polymer dissolved in a 60/40 mixture of toluene/DMF.

This solution cooking technique providea an easy way of making this polymer, but it is difficult to evaluate the physical properties of such solutions. Thus, the solution collected from an individual cook is spread coated onto release paper and dried at 300OF to remove the solvent.

This film can then be stripped from the paper and used to conduct various physical property tests.

A. Modulus, Tensile Strength, and Elongation One gram of cadmium stearate was added to 200 grams of dried polymer and intimately mixed on a two roll rubber mill. A 0.040 inch slab of polymer was removed from the mill and was used to make tensile specimens. This was done by pressing the slab between two polished plates in a heated Wabash press for 15 minutes at sufficient temperature and pressure to yield a 0.010 0.014 inch film. Temperatures and pressures varied depending upon the particular formulation. The press was cooled to room temperature and the film was removed from between the plates. From this film, five samples were cut in the size of one inch by six inches. These were then tested on an Instron and averages of 100% modulus, 200% modulus, tensile strength, and elongation were calculated from the test results. The temperature for the milling and pressing operations were observed and found to be related to formulation changes.

B. Toluene Swell Two pieces, one inch by two inches, of the pressed film were immersed in toluene for 24 hours. Measurements of volume by displacement of alcohol before and after toluene immersion were used to calculate volume swell.

WO 90/1109 PCT/US90/01477 -13- C. Flow Temperature and Flow Rate A three to five gram sample of polymer was finely chopped and used to determine the temperature at which the polymer would flow at a measurable rate and to determine the rate itself on a Kayness, Inc. extrusion plastometer Model D-0051. A measurable rate was defined as greater than 0.15 grams per 10 minutes. Thus at temperatures below the flow temperature, neither fusion of the polymer nor flow greater than 0.15 grams is achieved. The flow rate is defined as the number of grams extruded from the barrel of the plastometer in a period of ten minutes.

D. Brookfield Viscosity Fifteen grams of polymer were dissolved in 85 grams of dry dimethyl formamide and warmed to 30 degrees Centigrade in a constant temperature bath overnight in a closed waterproof container. The viscosity was then measured on a Brookfield viscometer as quickly as possible after removing from the bath. Viscosity data is reported in cps.

E. Glass Transition Temperature (Tg) Several polymer slabs, including a known control, were measured for T This work was done by two techniques, mechanical spectroscopy which measures the change in physical properties due to passing through the glass transition temperature and DSC (differential scanning calorimetry) which measures the second order transition defined as glass transition temperature.

The improvements and advantages associated with the linear polyurethane polymers developed in this invention are illustrated below in the Examples.

Examples The scope of the invention is further described in connection with the following examples which are set forth for the sole purpose of illustrating the preferred WO99/11309 PCT/US90/01477 -14embodiments of the invention and which are not to be construed as limiting the scope of the invention in any manner. In these examples, all parts given are by weight unless otherwise specified.

The specific preferred chemicals utilized in the examples are listed below as follows: WO 90/11309 PCT/US90/O 1477

POLYOLS

Oil Humber Suppl1ier Identity Type PPG Industries PPG Industries PPG Industries QC Chemicals QC Chemicals Whitco Chemical Duracarb 120 Duracarb 122 Duracarb 124 Polymeg 1000 Polymeg 2000 Form-rez 44-112 aliphatic carbonate 31.0 aliphatic carbonate 95.0 aliphatic carbonlate 58.0 PTMEG ether 111.9 PTMZG ether 55.7 ester 113.3 Equ iv.

Wt.

428.

590.0 967.2 501.3 1007.2 495.1

ISOCYANATES

Equiv.

CO Ift. Supplier Identity T-Y-P-e

ICI

ICI

Mobay Corp.

BAS F Dow chemical Rubinate 44 Rubinate LF-179 Mondur PF Lupranate MP-102 Isonate 181.

MDI

liquid MDI liquid MDI liquid MDI liquid MDI 33. 6 23.0 22.9 23.*0 23.0 125.*0 102.5 183 .4 182.*5 182.5 EXTENDER DIOLS Supplier Identit~y Equivalent Weight BAS F DOW Chemical 1, 4-butanediol.

tripropylene glycol SUBSTITUTE SHEIET WO 90/11309 PCT/US90/01477 -16- Examples 1-12 Table I illustrates the effect that modified liquid MDI components have on flow temperature of various polyurethanes compared to those made from the corresponding unmodified MDI compound. The table lists six polyurethanes made with various polyols, including some mixtures of polyols.

Each two examples represent a polyurethane made from liquid MDI and its analog made from the corresponding MDI unmodified, solid component. As shown in the table, the percent hard segment is equivalent in each comparison. Examples 1, 3, 5, 7, 9 and 11 are in accordance with the present invention, while Examples 2, 4, 6, 8, 10 and 12 are included for comparison. In all cases, the liquid MDI polymer has a lower flow temperature than its solid MDI analog. Flow temperature is that temperature at which a measurable flow is first observed when tested on an extrusion plastometer.

Since flow temperature is a measure of the temperature at which the polymer may be processed on calendering and extrusion equipment, the use of the liquid MDI components allows the making of polymers which process at lower temperatures, and therefore are easier to process and manufacture into articles such as calendered sheets for coated fabrics. The results demonstrate that all experimental polymers made with liquid MDI components exhibited lower milling temperatures than those of their solid MDI analogs.

Although Table I illustrates polyurethanes made with polyether, polyester, and polycarbonate polyols, it would be expected that this improvement would be present regardless of the specific type of polyol used.

Examples 13-16 The section on chemicals lists four commercially available liquid MDI components and describes how they are produced. Table II demonstrates that these four isocyanates are essentially equivalent in their ability to WO 90/11309 PCT/US90/01477 -17modify the flow temperatures and therefore the processing temperatures of polyurethanes made from them. Any one of these four preferred isocyanates may be employed in the development of low temperature processable polyurethanes. As noted above, a wide variety of difunctional isocyanates which are modified by reaction with low molecular weight polyols would also be suitable for use in this invention.

Examples 17-22 Table III compares polycarbonate polyurethanes made from liquid MDI components against those made with solid MDI components. Examples 17-19 are in accordance with the inventio,, while Examples 20-22 are comparative. It can be seen from the data that polyurethane polymers made using liquid MDI exhibit better physical properties, particularly tensile strength, compared to those made with solid MDI. Flow temperatures were not specifically measured on the liquid MDI polymers, but processing on the mill was found to be significantly better than for polymers made with the comparable unmodified, solid MDI compounds.

It should also be noted that the use of liquid MDI allows the production of polyurethane elastomers having a higher percent hard segment. This is advantageous because in general the urethane linkages are much more stable to various degradation forces hydrolysis, oxidation, etc.) than are ether, ester or other bonds in the polyol backbone.

Examples 23-38 Polyurethane elastomers made from an aliphatic polycarbonate polyol, liquid MDI and 1,4-butanediol were prepared as shown in Table III, Examples 17-19. A mixture of polycarbonate polyols was used in Example 38 of table IV.

Excellent physical properties, particularly tensile strength and elongation, were achieved in these formulations. Upon further analysis of the tensile curves, it was observed that these polymers were more plastic than elastomeric in character.

WO 90/11309 PCT/US90/01477 -18- Thus, these polymers could be described as hard and tough with a high yield value as illustrated by the 100% modulus values.

However, evaluation of films of the polycarbonate based polyurethane polymers exhibited poor cold crack properties.

To improve low temperature properties without sacrificing the properties of the polycarbonate backbone, a copolyol was introduced into the system, as shown in Examples 23-37 of Tables IV (A A polytetramethylene glycol ("PTMG") polyol was found to have the compatibility with the specific polycarbonate polyols used, with the molecular weight of 1000 and 2000 each found to be 'suitable.

From Table IV it is observed that physical properties, i.e. modulus, elongation, tensile strength, and toluene swell are affected by percent weight secondary and by percent hard segment. Thus, as the percent of seconrary polyol (PTMG polyether) is increased, (or the polycarbonate is decreased), modulus decreases and the polymer becomes more elastomeric than plastic. Also as the percent hard segment decreases, the modulus decreases but toluene swell (a measure of solvent resistance) increases. From this information, one skilled in the art can select the optimum combinations for the desired final product.

Two different molacular weight polyethers were evaluated. The results tend to indicate that change in properties is mainly related to the percent (by weight) of secondary polyol rather than to the molecular weight of the PTMG polyol. It is also observed that there is some lowering of tensile strength at higher percent secondary polyol, but at a weight ratio of primary/secondary polyol of greater than or equal to one, this is not significant. Increased molecular weight of these polymers can also be used to counteract this effect.

.'WO 90/11309 PCr/US9/01477 -19- Examples 39 and The ability to custom design a polymer to meet various physical requirements is suggested by the results of Table V.

It is also possible to improve low temperature properties.

Table V compares two formulations which are similar with the exception of the introduction of 20% PTMG polyether polyol into the polymer (Example 40). Again the changes in physical properties can be observed.

The T of the formulations of these examples was determined by mechanical spectrometry and differential scanning calorimetry (DSC) to be as follows: Polymer M.S. DSC of Example Tg Tg 39 50.9-56.0 21 30.9 11 Thus the mixture of the PTMG polyether polyol with the polycarbonate polyol resulted in a significant lowering of the T (in degrees Centigrade). Thus, this polyol mixture increases the cold cracking and low temperature impact properties of the resulting linear polyurethane polymer.

Examples 41-45: Table VI illustrates the reproducibility of the invention by listing several formulations which were made at different times on different days.

Examples 46-48 As described above, most of the elastomers of the Examples were made using a solution polymerization technique and then dried for testing and experimental use. This technique is not a suitable process for use in commercial manufacturing, and other methods of polymerization can be used, one is to mix together the polyol(s) and diol(s) and then feed this stream with a stream of isocyanate to an intensive mixer.

The two streams when mixed are heated to initiate WO 90/11309 PCT/US90/01477 polymerization and extruded as a polymer (one-shot). Another approach is to first make prepolymers from the polyol(s) using an excess of isocyanate and then to extend this material with the diol(s) in the presence of heat. Two experiments were conducted in an attempt to simulate and evaluate these two approaches. In both cases, the formula of Example 40 was used.

The one-shot experiment was conducted by weighing the polyols and diol into a plastic container and mixing well under nitrogen. The appropriate amount of LF-179 was then added, mixed well, capped under nitrogen and placed in an nven at overnight. The prepolymer approach was conducted by mixing the polyols thoroughly with an excess of isocyanate (per formula), followed by capping and heating for two hours at 850C. After removing the sample from the oven, an appropriate amount of diol was added, quickly mixed, capped and returned to a 900C oven overnight.

Table VII gives a comparison of a solution cook to a one-shot and a prepolymer cook. In all cases, flow temperature is still lower than a comparable unmodified MDI polymer and physical properties are very similar. Working these polymers on a rubber mill indicates that the prepolymer approach may actually yield a lower temperature processing polymer than the one-shot approach. Also, the prepolymer approach provides a much clearer polymer which is a sign of better uniformity and compatibility. Therefore the prepolymer approach is preferred although the one-shot approach will indeed yield acceptable polymers and, it is seen that a new linear polyurethane elastomers useful for a wide variety of applications can be prepared.

While it is apparent that the invention herein disclosed is well calculated to fulfill the objects above stated, it will be appreciated that numerous modifications and embodiments may be devised by those skilled in the art, nd it is intended that the appended claims cover all such modifications and embodiments as fall within the true spirit and scope of the present invention.

WO 90/11309 PCT/USg9001477 -21- TABLE I(A) FORMULATIONS

EXAMPLE

1 2 3 4 6 7 8 9 11 ISOCYA- PRIMARY NATE POLYOL LF-179 DURACARB 120 MDI DU.ACARRB 120 LF-179 DURACARB 120 MDI DURACARB 120 LF-179 POLYMEG 1000 HDI POLYMEC 1000 LF-179 DUPACARB 122 MDI DURACARB 122 LF-179 DURACARB 124 MDI DURACARB 124 LF-179 FORl-REZ 44-112 HDi FORM-REZ 44-112

SECONDARY

POLYOL

POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 EQUIV WEIGHT PREPOI RATIO RATIO NCO/O1l 2.410 1.025 2.503 2.410 1.025 3.340 3.565 1.516 2,600 3,55 1.516 1.478 2.377 3,171 3.546 2.079 3.163 3.546 2.079 4.220 1.575 1.512 4,471 1.575 1.513 1.517 1,970

FINAL

I NCO, 011 0.981 0,980 0.950 0,950 0.950 0M950 0.950 0.951 0.950 0.950 0.980 2.633 0.980 Notea: 1. Equivalent and woight ratio refer to the ratio of primary to secondary polyol by equivalents or weight, respectively, 2. Each formulation contains 1,4-butane dLi4 as an extender in an amount necessary to achieve the final NCO/IL ratio.

8LIBSTITUTE SHEET TABLE, 1(B) -PROPERTIES EXAMPLE WEIGHT WEIGHT I HARD 100% 200% TENSILE PERCENT TOLUENE FLOW FLOW BROOKFIELD PRIMARY SECONDARY SEGMENT MODULUS MODULUS STRENGTH ELONATION SWELL TEMP RATE VISCOSITY 26.91 26.93 30-19 30.10 50.00 50.00 33.80 33.80 30.10 30-10 55.00 55.00 26.26 26.28 19.92 19.90 46.83 46.79 49.89 50.00 50.00 50.00 49-90 50.00 50.00 50.00 65-00 896 1696 1028 761 626 1082 1878 1198 1740 555 16.30 16.20 19.90 19.90 1354 1920 1746 905 787 1697 1707 810 1885 4772 2550 5094 1324 1968 1300 3745 191,1 3732 1731 6928 3604 531 412 494 496 655 77 413 148 439 112 579 79.2 69.6 104.6 79.0 92.0 60.0 1.05.0 62.3 100.0 80.4 51.4 150 195 150 160 150 186 150 194 160 210 175 1.825 9.400 1.868 7.686 10. 070 5-924 6.158 1.555 4.284 5.662 7.578 115 57 93 27 54 27 42 34 56 28 254 45.00 1553 43.2 179 18.060 Property Nor. Measured WO "1/11309 PC1'/US90/ 01477 -23- TABLE I1(A) FORKULATIONS EXAM PLE 13 14 16

ISOCYA-

NATE

LP- 179 ISO.181 MP. 102 MON PF

PRIMARY

POLYOL

DURACARBI

DURACARBI

DURACARBI

DURACARB:

SECONDARY

POLYOL

POLYMEG 2000 POLYMEG 2000 POLYHEG 2000 POLYMEG 2000

EQUIV

RATIO

3.681 3.558 3.558 3.558

WEIGHT

RATIO0 1.565 1.512 1.512 1.512

PREPOL

NCO/OH

2.618 2.606 2.606 2,606

FINAL

NCO/Oi1 0.952 0.951 0. 0.950 Notes: 1. Equivalent and weight ratio refer to the ratio of primary to secondary polyol by equivalents or weight, respectively, 2. Each formulation contains 1,4-butane diol as an extender in an amount necessary to achieve the final NCO/OH ratio.

StuIM~TJT I C I E (AMPLE WEIGHT

PRIHARY

B. 30.38 1.4 30.10 30.10 1.6 30-10

WEIGHT

SECONDARY

19.41 19.90 19.90 19.90

HARD

SEGMENT

50.21 50.00 50.00 50.00 100%

MODULUS

1239 1057 1093 1057 TABLE 11 (B) 200%

MODULUS

2066 1598 1638 1776

PROPERT!

TENSILE

STRENGTH

564.9 3962 4239 5668

PERCENT

ELONGATION

4-78 492 504 507

TOLUENE

SWELL

112.5 94.0 85.0 90.0

FLOW

TEMP

150 150 150 160

FLOW

RATE

1.739 4.990 1.815 2.436

BROOKFIELD

VISCOSITY

82 121 ill WO "0/11309PC/SOO17 PCr/US90/01477 TABLE III(A) FORMULATIONS ISOMiA- EXAMPLE NATE 17 LF-179 18 LF-179 19 LF-179

MDI

21 MDI 22 MDI

POLYOL

DURACARB 120 DURACARLB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 PREPOL FINAL, NCO/OR NCO/OH 2.477 0.992 2.477 0.992 2.477 0.992 2.475 0,990 2.700 0.990 2.901 0.990 Note: Each formulation contains 1,4-butane diol as an extender as necessary to achieve the final NCO/0II ratio.

*U.;'3TI SZ- TABLE III(B) PROPERTIES EXAMPLE WEIGHT

PRIMARY

17 45.19 18 45.19 19 45.19 53.19 21 50.76 22 48.79 1A R D

SEGMENT

54.81 54.81 54.81 46.81 49.24 51.21 100%

MODULUS

2605 2086 1924 1398 2372 2927 200%

MODULUS

3515 3909

TENSILE

STRENGTH

6739 6100 5904 2528 4469 4763

PERCENT

ELONGATION

297 351 367 304 304 288

TOLUENE

SWELL

68-0 53.0 54.0 78.0 78.0 48.5

FLOW

TEMP

160 160 175

FLOW

RATE

12.620 12. 620 17 .390

BROOKFIELD

VISCOSITY

36 36 v- Property not measured t- Flow temperature not specifically measured but visually observed to be lower (on the order of about 150F) compared to that of Examples 20-22.

WO 90/11309 PCT/US90/01477 -27- TABLE IV(A) FORMULATIONS

ISOCYA-

EXAMPLE NATE

PRIMARY

POLYOL

SECONDARY

POLYOL

LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 LF-179 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACAKRB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 DURACARB 120 POLYMEG 1000 POLYMEG 2-)00 POLYMEG 1000 POLYMEG 1000 POLYMEG 1000 POLYMEG 1000 POLYMEG 1000 POLYMEG 1000 POLYMEG 2000 POLYMEG 1000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 DURACARB 122

EQUIV

RATIO

8.988 8.996 3.995 2.999 2.999 2.327 2.334 1.498 2.410 0.999 2.333 2.333 2,410 2.410 1.032 1.000 I I 7.677 3.949 3.412 2.562 2.562 1,988 1.993 1.280 1.025 0.853 1.025 1.025 1.025 1.025 0.439 2.480 2.480 2,479 2.475 2.475 2.431 2.099 2.478 2.826 2.478 2.481 2,481 2.503 2.120 2.520 0.977 0.977 0.977 0.980 0.980 0.977 0.980 0.977 0.983 0.977 0,977 0.977 0.981 0.984 0.983 WEIGHT PREPOL FINAL RATIO NCO/OH NCO/OH 0.725 2.475 0.9'90 Notes: 1. Equivalent and weight ratio refer to the ratio of primary to secondary polyol by equivalents or weight, repectively.

2. Each formulation contains 1,4-butane diol as an extender in an amount necessary to achieve the final NCO/OH ratio.

SUBSTITUTE SHEET TABLE IV(B) PROPERTIES E:XAMLE WEIGHT WEIGHT PERIMARY SECONDARY HARD 100% 200% TENSILE PERCENT TOLUENE FLOW FLOW BROOKFIELD 40.25 38.36 35.51 33.22 33.22 30.81 33.88 26.24 25.26 21.70 2 6 91 26.91 5.24 9.71 10.41 12,97 12.97 15.50 17.00 20.50 24.65 25.43 26.26 26.26 SEGMENT MODU-LX, MODULUS 54.51 2256 3262 51.93 1799 3155 54.08 1808 2917 53.81 1947 3193 53.81 1704 3055 53.69 1068 2321 49.12 625 1466 53.26 7 312 1536 50.09 1243 2088 52.87 1071 1705 46.83 844 1284 46.83 867 1354 STRENG74 6386 6644 6573 7284 7294 5846 6452 5542 6563 4388 5803- 6041

ELONGATION

362 355 386 371 374 388 439 450 521 463 579 558

SWELL

68.0 106.0 88.0 76.0 72.0 9i.0 123 .0 79.0 81.0 77.0 100.0G 96.0

TEM-P

160 150 150 150 150 150 150 150 160 150 150 150

RATE

3.850 1.039 1.720 0.821 0.750 5.232 2.495 5.272 1.790 7.580 0.980 0.905

VISCOSITY

79 104 84 227 63 63 141 51 217 153 188 TABLE IV(B) (Continu~d) EXARPLE WEIGHT

PRIMARY

26.91 36 29.19 37 17.50 38 20.8

WEIGHT

SECONDARY

26.26 28.49 39.86 28.1

HARD

SEGMENT

46.83 42.32 42.64 50.4 100%

MODULUS

896 489 520 200%

MODULUS

1354 712 684 TENISILE PERCENT STRENGTH ELONGATION 4772 531 5362 612 3170 683

TOLUENE

SWELL

79.2 164.0 148.0 105.0

FLOW

TEMP

150 160 150 150

FLOW

RATE

1.825 2.313 2.792 1.608

BROOKCFIELD

VISCOSITY

115 229 99 134 Property Not Measured WO 90/11309 WO 9011309PCTIUS90/01477 TABLE V(A) FORMULATIONS I SOCYA EXAMPLE NATE

PRIMARY

POLYOL

SECONDARY

POLYOL

EQUIV WEIC1UT PREPOL FINAL RATIO RATIO NCO/OH NCO/OH1 39 LF-179 DURACARB,120 LF-179 DURACARB 120 2.477 0,992 2.600 0.950 POLYMEG 2000 3.565 1.516 Notes: 1. Equivalent and weight ratio refer to the ratio of primary to secondary polyol by equivalents or weight, respectively.

2. Each formulation contains 1,4-butane diol as an extender in an amount necessary to achieve the final NCO/0Oi ratio.

SUBSTITUTE SHEET.

TABLE V(B) PROPERTIES FLOW FLOW BROOKFIELD TEMP RATE VISCOSITY 96 WEIGHT WEIGHT X-AMPLE PRIMARY SECONDARY HARD 100% 200% TEN1SILE PERCENT TOLUENE SEGM.1ENT MODULUS MODULUS STRENGTH ELONGATION SWZLL 45.19 54.81 2086 49.89 1028 6100 5094 53.0 104.6 150 1.686 30.19 19.92 1746

(I)

C

w

(I)

C

-I

m ci) m

TI,

'-4 -Property- not measured WO 90/11309 WO 9011309PCr/US90/0 1477 -32- TABLE VI(A) FORMUJLATIONS

EXAMPLE

.41 42 43 44

ISOCYA-

NATE

LF- 179 LF- 179 LF-179 LF- 179 LF- 179

PRIMARY

POLYOL

DURACARB

DURACARB

DURACARB

DURACARB

DURACARB

SECONDARY

POLYOL

POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000 POLYMEG 2000

EQUIV

RATIO

2.333 2,333 2.410 3.565 3.565

WEIGHT

RATIO

1.025 1.025 1.025 1,516 1.516

PREPOL

NCO/il 2.481 2.481 2,503 2.600 2.600

FINAL

NCO/OH

0.977 0,977 0.981 0.950 0.950 Notes: 1. Equivalent and weight ratio refer to the ratio of primary to secondary polyol by equivalents or weight, respectively.

2. Each formulation contains 1,4-butane diol as an extender in an amount necessary to achieve the final NCO/Oil ratio, SUBSTITUTE SHEET TABLE VI(B) -PROPERTIES ExAIP;LF.

41 42 43 44 I WEIGHT

PRIMARY

26,91 26.91 26.91 30.19 30.19

WEIGHT

SECONDARY

26-26 26.26 26.26 19.92 19.92

HARD

SEGMENT

46.83 46.83 46-83 49.89 49.89 100%

MODULUS

867 844 896 1072 1028 200%

MODULUS

1354 1284 1354 1824 1746

TENSILE

STRENGTH

6041 5803 4772 5405 5094

PERCENT

ELONGATION

558 -579 531 488 494

TOLUENE

SWELL

96.0 100.0 79.2 92.3 104.6

FLOW

TEMP

150 150 150 150 150

FLOW

RATE

0.905 0.980 1.825 1.440 1.868

BROOKFIELD

VISCOSITY

188 153 115 105 93 WO 90/11309 PCr/US9O/01477 -34- TABLE VII(A) FORMULATIONS

EXAMPLE

46 47 48

ISOCYA-

NATE

LF-179 LF-179 LF-179

~I

PRIMARY

POLYOL

DURACARB

DURACARB

DURACARB

SECONDARY

POLYOL

POLYMEC 2000 POLYMEG 2000 POLYMEG 2000

I

EQUIV

RATIO

3.565 3.565 3.565

WEIGHT

RATIO

1.516 2,079 2.079

PREPOL

NCOZOH

2.600 2.600 2.600

FINAL

NCO1O)l 0.950 0.950 0.950 Notes: 1, Equivalent and weight ratio refer to the ratio of primary to secondary polyol by equivaients or weight, respectively.

2, Each formulation contakns 1,4-butane diol as an extender in an amount necessary to achieve the final NCO/Oi ratio, SUBSTITUTC

SHEIE

TABLE VII(B) PROPERTIES SXAHPLE UEIGHT

PRIMARY

46 30.19 47 30.20 48 30.2b %4 WEIGHT

SECONDARY

19.92 19.90 19.90 W: HARD

SEGMENT

49.89 49.90 49.90 100%

MODULUS

1028 915 1144 200%

MODULUS

1746 1691 2342

TENSILE

STRENGTH

5094 4885 6634

ELONGATION

494 442 409

TOLUENE

SWELL

104. A 115.0 105.0

FLOW

TEMP

150 160 160

F~LOW

RATE

1.868 2.207 1.111

BROOKFIELD

VISCOSITY

93 202 373

Claims (27)

1. A process for the preparation of a linear thermoplastic polyurethane elastomer composition from a polyol component, a diisocyanate compound, and a first extender component having a molecular weight of less than 500, said process including the step of lowering the processing temperature of said polyurethane by reacting the diisocyanate compound with said first extender in a molar ratio of above 2:1 to form a modified diisocyanate component having a functionality of about 2 prior to reacting the modified diisocyanate component with the polyol component, thus forming a linear thermoplastic polyurethane elastomer composition having lower temperature processing characteristics compared to similar compositions wherein the diiso- cyanate compound is not modified.

2. The process of claim 1 wherein the polyol component is a polyether polyol, polycarbonate polyol, polycaprolactone polyol, polyester polyol, polybutadiene polyol or mixtures thereof. Sf 3. The process of claim 1 or claim 2 wherein the 25 first extender component is a polyol or amine compound.

4. The process of claim 3 wherein the first extender component comprises a diol. S 30 5. The process of any one of claims 1 to 3 which further comprises reacting the modified diisocyanate with a second extender component.

6. The process of claim 5 wherein the modified diisocyanate is reacted with the polyol prior to reacting with the second extender component. 7, The process of claim 5 or 6 wherein the second extender component is a polyol or amine compound having a 40 36 V^ *y, *^r molecular weight of less than 500 and which is different from said first extender component.

8. The process of any one of claims 1 to 7 wherein between 10% to 30% by weight of the di- 'yanate compound is modified so that the modified diis t /anate component has an NCO content of between 14 and 33%.

9. The process of claim 8 wherein the NCO content of the modified diisocyanate component is between 20 and 26%. The process of any one of claims 1 to 9 wherein the diisocyanate compound primarily includes 4,4'-diphenyl methane diisocyanate.

11. The process of any one of claims 1 to 3 wherein the first extender component is a polyol having a molecular weight between 60 and 250.

12. The process of any one of claims 1 to 3 wherein the first extender component is 1,4-butane diol, tripropylene glycol, dipropylene glycol, propylene glycol, ethylene glycol, 1,6-hexane diol, 1,3-butane diol, neopentyl glycol, ethylene diamine or mixtures thereof.

13. A linear thermoplastic polyurethane elastomer composition including: a polyol; a diisocyanate compound, and a first extender component having a molecular weight of less than 500; wherein the diisocyanate compound is initially reacted with the first extender component in a molar ratio of above 2:1 so as to form a modified diisocyanate component having a functionality of about 2 prior to reaction with the polyol components to provide lower temperature processing characteristics compared to similar compositions wherein the diisocyanate is not modified. 37

14. The composition of claim 13 wherein the polyol component is a polyether polyol, polycarbonate polyol, polycaprolactone polyol, polyester polyol, polybutadiene polyol or mixtures thereof. The composition of claim 13 or claim 14 wherein the first extender component is a polyol or amine compound.

16. The composition of claim 13 or 14 wherein the first extender component comprises a diol.

17. The composition of claim 13 further including a second extender for reaction with the modified diiso- cyanate compound.

18. The composition of claim 17 wherein the second extender component is a polyol or amine compound having a molecular weight of less than 500 and which is different from said first extender component.

19. The composition of any one of claims 13 to 18 wherein between 10 to 30% by weight of the diisocyanate compound is modified so that the modified diisocyanate S 25 component has an NCO content of between 14 and 33%. The composition of claim 19 wherein the NCO content of the modified diisocyanate component is between and 26%. S

21. The composition of any one of claims 13 to wherein the diisocyanate compound primarily includes 4,4'-diphenylmethane diisocyanate.

22. The composition of any one of claims 13 to 21 wherein the first extender component is a polyol having a molecular weight between 60 and 250.

23. The composition of any one of claims 13 to 21 38 wherein the first extender component is 1,4-butane diol, tripropylene glycol, dipropylene glycol, propylene glycol, ethylene glycol, 1,6-hexane diol, 1,3-butane diol, neopentyl glycol, ethylene diamine or mixtures thereof.

24. A linear thermoplastic polyurethane elastomer composition including: a polycarbonate polyol; a polyether polyol; a diisocyanate compound; a first extender component having a molecular weight of less than 500; and a second extender component; wherein the diisocyanate compound is initially reacted with one of the extender components in a molar ratio of above 2:1 so as to form a modified diisocyanate component having a functionality of about 2 prior to reaction with the other components to provide relatively low temperature processing properties to the composition, whereas the polyol components provide superior hydrolytic stability and low temperature flexibility properties to the composition. The composition of claim 24 wherein the first S 25 extender component is a polyol or amine compound. S26. The composition of claim 25 wherein the first extender component comprises a diol.

27. The composition of any one of claims 24 to 26 wherein the diisocyanate compound primarily includes 4,4'-diphenyl methane diisocyanate.

28. The composition of any one of claims 24 to 27 wherein the first extender component is a polyol having a molecular weight between 60 and 250.

29. The composition of claim 24 or claim wherein at least one of the extender components comprises 40 39 u 1,4-butane diol, tripropylene glycol, dipropylene glycol, propylene glycol, ethylene glycol, 1,6-hexane diol, 1,3-butane diol, neopentyl glycol, ethylene diamine or mixtures therecf. The composition of any one of claims 24 to 29 wherein the polyether polyol and polycarbonate polyol are present in the polyol component in a relative amount of between 2:1 to 1:8.

31. The composition of any one of claims 24 to wherein one extender component comprises 1,4-butane diol and the other extender component comprises tripropylene glycol.

32. The composition of any one of claims 24 to 31 wherein between 10% to 30% by weight of the diisocyanate compound is modified so that the modified diisocyanate component has an NCO content of between 14 and 33%.

33. The composition of claim 32 wherein the NCO content of the modified diisocyanate component is between and 26%. S 25 34. A linear thermoplastic polyurethane elastomer composition prepared according to the process of any one of claims 1 to 12.

35. A process for the preparation of a linear 30 thermoplastic, polyurethane elastomer composition according to claim 1, substantially as herein described with reference to any one of the Examples.

36. A linear thermoplastic polyurethane elastomer according to claim 13, substantially as herein described with reference to any one of the Examples.

37. A, linear thermoplastic polyurethane elastomer according to claim 24, substantially as herein described S\ <40, 40 with reference to any one of the Examples. DATED: 2 August 1993 PHILLIPS ORMONDE T Attorneys for:S, I REEVES BROTHERS, INC. i 5666Z 41 INTERNATIONAL SEARCH REPORT International Arialication No PCTIUS90/01477 1. CLASSIFICATION OF SUBJECT MATTER (it several claserication symbols apply, indicate sall) According to International Patent Classification (IPC) or to both National Classitication and IPC IPC C08G 18/10, 18/44, 18/48 U.S. CL: 528/60, 61, 65, 66, 76, 85, 59 1t. FIELDS SEARCHED Minimum Documentation Searched4 Classification System PClassification Symbols U.S. 528/59,60,61,65,66,76,85,59 Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included In the Fields Searchedb Ill, DOCUMENTSCONSIDERED TO BE RELEVANT 14 Calegory7 Citation of Document, I' with indication, where appropriate, of the relevant opassages 17 X :US, A, X US, A A ~US, A) A US, A, A 'US, A, Y US, A, 4,307,004 (SCHUIHIACHER) 22 December 1981 see the entire document 4,791,187 (SULING) 13 December 1988 see the entire document 4,683,171 (KUGA) 28 July 1987 see claims 12-14 4,705,721 (FRISCH) 10 November 1987 see columns 1-3 .3,904,796 (ZORlN) 09 September 1975 see column 4, lines 51-55 4,306,052 (BONK) 15 December 1981 see the entire document Relevant to Claim No. IN 11-20 11-20 11-20 11-20 1-20 t 1-10 1-10 YP US, A, 4,868,268 (KILLER) 19 September 1989 see the entire document Special categories of cited documents, 13 document defioinIng the general sitate Of the art Which Is not Considered to be of Particular relevance earliqr document but published on or aftar the international riling date document which may throw doubts on prittit claim(s) or which is cited to establish the Publication dateC of another titatlon or other special reason (as Specified) 11011 document reterrlng to an oral disclosure, use, eshibition or other means "P11 document Published prior to the international filing date but later than the oliorily date claimed later ktibcument Published after the international filing date or Prilirity date and not in conflict with the application but cited lo understand the principle or Itheory undellylng the rInverr/ion 'W1 doodment of particular irtvance% the Claimed invention Ianoo be Considered novel or Cannot be considered to involve an Inventive step document of particular relevance, the claimed Invention cannot be considered to involve en Inventivestp hete docuW~lnt is combined with one or more othr su~ch docu* ments. iuch combination being obvious to a person skilled In trie at,, 11&" documeM. member of the same patent family IV. CERTIFICATION Date of the Actual Completion of the International Search I Dat# o1 Mellig 01 this Inltr to ctrh Report JUNE 1990 06 AUG-1 International Searching Authority I tr ISA/US D04ALEY Form I'CT11SAi21O teecond sheet) (May 1988)