POLYESTERCARBONATE-POLYURETHANEUREA FIBERS

Abstract: Polyestercarbonate-polyurethaneureas based on polycarbonate diols which in turn are based on mixtures of poly(hexane-1,6-carbonate) diol and poly( epsilon -caprolactone) diol, cyclic aliphatic diisocyanates and diamine chain extenders are provided.

Description: TITLE POLYESTERCARBONATE-POLYURETHANEUREA FIBERS BACKGROUND OF THE INVENTION Field of the Invention This invention relates to spandex comprising polyestercarbonate-urethaneureas and more specifically to spandex prepared from a polycarbonate diol made from poly (hexane-1, 6-carbonate) diol and poly (ε-capro- lactone) diol, a cyclic aliphatic diisocyanate, and a diamine chain extender. Description of the Background Art Spandex prepared from ordinary polycarbonate diols is known. For example, United States Patent No. 4,837,292 discloses spandex prepared from the reaction product of polycarbonate diols with diisocyanates and diamine chain extenders . The polycarbonate diols disclosed are poly (pentane-1, 5-carbonate) diol, poly (hexane-1, 6-carbonate) diol, copolymers thereof and mixtures thereof. Italian Patent No. 710,940 discloses spandex made from hexamethylene glycol-based polycarbonate diols, aromatic diisocyanates, and aliphatic diamines . Although spandex based on ordinary polycarbonate diols can have superior environmental resistance, it often has low flexibility and elongation. As disclosed in Japanese Patent Application Publication No. 3-234813, (1991) , polyurethaneureas based on polycarbonate diols can be difficult to spin into spandex. Japanese Patent Application Publication No. 5-51428 (1993) discloses spandex based on polycarbonate diols and alicyclic diisocyanates but exemplifies the poor properties and environmental sensitivity of spandex based on polycaprolactone diol. It would, therefore, be desirable to prepare a spandex which can be readily spun, which has good resistance to environmental degradation, and which has soft stretchability . SUMMARY OF THE INVENTION The spandex of the present invention is a polyestercarbonate-polyurethaneurea which is the reaction product of: a modified polycarbonate prepared by reacting a mixture of poly (hexane-1 , 6-carbonate) diol and poly (ε-caprolactone) diol with a dialkylcarbonate; a cyclic aliphatic diisocyanate; and a diamine chain extender. DETAILED DESCRIPTION OF THE INVENTION As used herein, "spandex" has its customary meaning: a manufactured fiber in which the fiber- forming substance is a long chain synthetic elastomer comprised of at least 85% by weight of a segmented polyurethane . The polyurethane can generally be prepared by "capping" a polymeric glycol with a diisocyanate and reacting the resulting "capped glycol" (sometimes called an "NCO-terminated prepolymer") with a diamine to form a polyurethaneurea . The chain extension and subsequent processing are preferably carried out in a suitable solvent. The polyurethane- urea-based spandex can then be prepared by dry or wet spinning the polymer solution; dry spinning is pre erred. The polymeric diol used in making the spandex of the present invention is a modified polycarbonate diol prepared by transesterifying a mixture of poly(hexane- 1, 6-carbonate) diol and poly (ε-caprolactone) diol with a dialkylcarbonate. "Dialkylcarbonate" is intended to include alkylene carbonates. Optionally, minor amounts of another diol may also be added, for example 1,3- propanediol, neopentyl glycol, 2-methyl-l, 4-butanediol, cyclohexanediol, and low molecular weight oligomers of poly (tetramethyleneether) glycol such as dibutyleneether glycol and tributyleneether glycol. For best elongation and spinnability, the weight ratio of poly (hexane-1 , 6-carbonate) diol to poly(ε- caprolactone) diol in the modified polycarbonate diol is in the range of about 95:5 to 65:35, preferably in the range of about 90:10 to 70:30. The number-average molecular weight of the modified polycarbonate diol is preferably in the range of about 1000 to 8000, more preferably in the range of about 1000 to 5000, and most preferably in the range of about 1500 to 3000. Good strength and elongation can be obtained when the modified diol is in this range. The modified polycarbonate diol is reacted with a cyclic aliphatic diisocyanate to form a capped glycol . Examples of suitable alicyclic diisocyanates include 4,4 ' -methylenebis (cyclohexylisocyanate) , hereinafter, "H12MDI", isophorone diisocyanate, methylcyclohexane- 2, 4-diisocyanate, methylcyclohexane-2, 6-diisocyanate, cyclohexane-1, 4-diisocyanate, hexahydroxylylene diisocyanate, and octahydro-1 , 5-naphthalene diisocyanate and mixtures thereof. Of these, H12MDI is preferred. The molar ratio of the modified polycarbonate diol to the alicyclic diisocyanate can be within a range of about 1:1.3 to 1:3.0. A molar ratio within a range of about 1:1.5 to 1:2.2 is preferable. Spandex having a high elongation-to-break and a high melting point can be obtained within this range. To complete the polymerization, a chain extender can be reacted with the capped glycol in a suitable solvent . The chain extender used in the present invention is a diamine, preferably a low-molecular- weight diamine. If a low-molecular-weight glycol is used, the melting point of the resulting yarn is low, and problems such as a long reaction time arise, which is undesirable. However, minor amounts of low- molecular-weight glycols can be used, provided this is within a range that does not eliminate or diminish the effects of the present invention. Examples of the low- molecular weight diamines include ethylenediamine, 1, 2-propanediamine, 1, 3-propanediamine, 1, 6-hexamethyl- ene diamine, 1, 4-cyclohexyldiamine, 1, 3-cyclohexyl- diamine and mixtures thereof. Ethylenediamine is preferred. The resulting solution of polymer can then be spun to prepare the spandex of this invention. The polyurethane fibers of this invention generally have a stress (load power) at 100% elongation of about 0.020-0.070 times the strength at break and a stress at 200% elongation of about 0.035-0.150 times the strength at break. Such fibers have a soft stretchability and a suitable tightening force. There are no particular restrictions on the diameter or the cross-sectional shape of the fibers of this invention. For example, the cross-section of the yarn can be circular or flat. Also, the presence of various stabilizers, pigments and the like within the fibers of the present invention is permitted and poses no problem. For example, light resistance agents and antioxidants can be incorporated with the polymer such as 2 , 6-di-t-butyl-4-methylphenol, benzotriazole stabilizers such as TINUVIN® stabilizers (Ciba Geigy) , phosphorus agents such as SUMILYZER® P-16 (Sumitomo Chemical) , and hindered amine stabilizers such as TINUVIN®. In addition, inorganic pigments such as titanium oxide, zinc oxide and carbon black; metal soaps such as magnesium stearate; germicides containing mercury, zinc, or compounds thereof; deodorizers; lubricants such as silicones or mineral oils; and various antistatic agents such as barium sulfate, cerium oxide, betaine and phosphorus -based compounds can also be spun into the spandex. In order to enhance further the durability of the spandex of this invention to light and nitrogen oxides, nitrogen oxide scavengers, such as HN-150 (an aromatic hydrazide manufactured by Nippon Hydrazine, Chiyoda-ku, Tokyo, Japan) ; heat and oxidation stabilizers such as SUMILYZER® GA-80 (a hindered phenol manufactured by Sumitomo Chemical, Osaka, Japan); and light stabilizers such as SUMISORB® 300#622 (manufactured by Sumitomo Chemical) can also be included. There is no particular restriction on the method for adding these, it being possible to employ conventional methods, for example by use of a static mixer. The polyurethane of the present invention can be prepared as follows. Because the polyurethane of the present invention utilizes a diamine chain extender whose reactivity with diisocyanate compounds differs from that of modified polycarbonate diols, it is preferable that production be carried out by a prepolymer method in which a polymeric diol is reacted with a diisocyanate in the range of about room temperature to about 200°C, thereby synthesizing an NCO-terminated prepolymer, adding to this a solvent that is substantially inert to the isocyanate groups and a chain extender that has been diluted with this solvent, then carrying out chain extension polymerization at about room temperature to about 60°C. Examples of suitable solvents include dimethyl formamide, dimethyl acetamide ("DMAc"), dimethyl sulfone oxide, methyl ethyl ketone, toluene, xylene, dioxane, tetrahydrofuran, ethyl acetate and N-methyl pyrrolidone. One or more of these solvents can be used, although it is preferable to use an amide-type solvent capable of achieving a high solute concentration, such as dimethyl formamide or DMAc. Monofunctional chain terminators such as diethylamine, butylamine, ethanol, propanol or butanol can be used to achieve the desired molecular weight or solution viscosity. Diethylamine is preferred. From the standpoint of spinnability and solution viscosity, the solids concentration is preferably about 30-40%, the solution viscosity is about 1200-6500 poises, preferably about 2000-6000 poises. The high- side melting point of the fibers of the invention is approximately 200°C to 250°C. This can be measured by Differential Scanning Calorimetry of finely cut fibers; two measurements are carried out and the second value is reported. Alternatively, a 12-micron film can be prepared by casting the polyurethaneurea solution, drying the cast solution in a nitrogen atmosphere, and measuring the second run value of the melting point. The number average molecular weight of the polymer is approximately 40,000 to 150,000, as measured by Gel Permeation Chromatography based on a polystyrene standard. Spinning can be carried out conventionally by either a wet spinning method or a dry spinning method, although is preferable to carry out a dry spinning method. TESTS The test methods used in the Examples of the present invention are described below. 1. Elongation at Break and Tensile Strength; Using an Instron (Canton, MA) 4502 tensile tester a spandex sample having a length of 5 cm was stretched to 300% elongation a total of five times at a rate of 50 cm/min, after which it was stretched a sixth time until it broke. In this way, the elongation at break and the tensile strength were both measured. Load power, the stress on the spandex during initial extension, was measured on the first cycle at 100% and 200% extension. 2. Durability: Spandex samples were irradiated in a Sunshine Weather Meter (sold by Suga Shikenki K.K., Shinjuku- u, Tokyo, Japan) for 15 hours at 63°C and 60% Relative Humidity ("RH"), after which the elongation at break and the strength were measured. 3. Yellowing Resistance: Using a Scott Controlled Atmosphere tester (made by Scott Research Laboratories, Inc.), the degree of yellowing (Δb value) of the spandex yarn after 50 hours of irradiation under an ultraviolet light (carbon arc) in 7 ppm of N0 2 gas and at 40°C and 60% RH, was measured with a color master. EXAMPLES In all Application Examples, a polycarbonate diol ("Nipporan 982N", molecular weight of about 2000, Nippon Urethanes, Osaka, Japan) was used. This diol was prepared by reacting a 9:1 by weight mixture of 2000 molecular weight poly (hexane-1 , 6 -carbonate) diol and 2000 molecular weight poly (ε-caprolactone) diol with a dialkyl carbonate. In each of the Application Examples, stabilizing additives were mixed with the polymer solution before spinning. The additives and their amounts (weight percent based on polymer) were: 1.7wt% HN-150, 0.9wt% SUMILYZER® GA-80, and 0.4wt% SUMISORB® 300#622. The total of these additives was 3.0wt% based on polymer. The Table (below) gives the test results for each of the spandex yarns in the Examples: stress (load power) at 100% elongation (grams per denier) , stress at 200% elongation (grams per denier) , elongation at break (%) , tensile strength at break (grams per denier) , ratio of (stress at 100% elongation) / (strength at break), ratio of (stress at 200% elongation) / (strength at break), durability and yellowing resistance. Application Example 1 First, 552 g of "Nipporan 982N" capped with 4 , 4 ' -methylenebis (cyclohexylisocyanate) (Sanyo Kasei, Kyoto, Japan) , molar ratio of modified polycarbonate diol to diisocyanate 1:1.8, was placed in a 2-liter flask and dissolved in 1094 g of DMAc, following which a solution of a mixture of 10.62 g of ethylene diamine and 0.52 g of diethylamine diluted with 100.2 g of DMAc was added dropwise over a period of 20 minutes, thereby carrying out the chain extension reaction and giving a viscous polymer solution. The viscosity of this polymer solution was measured with a falling ball-type viscometer, and was found to be 3540 poises at 40°C. The polymer solution (32% solids) was then conventionally dry-spun at a speed of 530 m/min with the speed ratio between the godet roller and the winder set at 1.45, and 18 -denier/filament yarn was wound onto a conventional cardboard tube. Application Example 2 First, 550 g of "Nipporan 982N" capped with 4,4 ' -methylenebis (cyclohexylisocyanate) , molar ratio of modified polycarbonate diol to diisocyanate 1:1.9, was placed in a 2-liter flask and dissolved in 1080 g of DMAc, following which a solution of a mixture of 11.92 g of ethylene diamine and 0.58 g of diethylamine diluted with 112.5 g of DMAc was added dropwise over a period of 20 minutes, thereby carrying out the chain extension reaction and giving a viscous polymer solution. The viscosity of this polymer solution was measured with a falling ball-type viscometer, and was found to be 1986 poises at 40°C. The polymer solution (32% solids) was then conventionally dry-spun at a speed of 530 m/min with the speed ratio between the godet roller and the winder set at 1.45, and 18- denier/filament yarn was wound onto a conventional cardboard tube . Application Example 3 First, 536.9 g of "Nipporan 982N" capped with a 9:1 by weight mixture of 4 , 4 ' -methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate, molar ratio of modified polycarbonate diol to total diisocyanate 1:1.8, was placed in a 2-liter flask and dissolved in 1067 g of DMAc. A solution of a mixture of 10.30 g of ethylene diamine and 0.50 g of diethylamine diluted with 97.2 g of DMAc was then added dropwise over a period of 20 minutes, thereby carrying out the chain extension reaction and giving a viscous polymer solution. The viscosity of this polymer solution was measured with a falling ball-type viscometer, and was found to be 2805 poises at 40°C. The polymer solution (32% solids) was then dry-spun at a speed of 530 m/min with the speed ratio between the godet roller and the take-up unit set at 1.45, and 18-denier/monofilament yarn was taken up onto a conventional cardboard tube. Application Example 4 First, 534.9 g of "Nipporan 982N" capped with a 9:1 by weight mixture of 4 , 4 ' -methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate, molar ratio of modified polycarbonate diol to total diisocyanate of 1:1.9, was placed in a 2 -liter flask and dissolved in 1051 g of DMAc. A solution of a mixture of 11.33 g of ethylene diamine and 0.55 g of diethylamine diluted with 106.9 g of DMAc was then added dropwise over a period of 20 minutes, thereby carrying out the chain extension reaction and giving a viscous polymer solution. The viscosity of this polymer solution was measured with a falling ball-type viscometer, and was found to be 1486 poises at 40°C. The polymer solution (32% solids) was then dry-spun at a speed of 530 m/min with the speed ratio between the godet roller and the take-up unit set at 1.45, and 18 -denier/filament yarn was taken up onto a conventional cardboard tube. Comparative Example - Prior Art An NCO-terminal urethane prepolymer was prepared by reacting a poly (tetramethyleneether) glycol having a molecular weight of 1800 with MDI at 90°C in the absence of solvent, and at a molar ratio of 1:1.58 for a period of 2 hours . This prepolymer was cooled to room temperature, after which 500 g was collected in a 2-liter flask, then dissolved in 1000 g of DMAc. A solution of a mixture of 7.80 g of ethylene diamine and 1.17 g of diethylamine diluted with 80.7 g of DMAc was then added, in this way carrying out the chain extension reaction and giving a viscous polymer solution. The viscosity of this polymer solution was measured with a falling-ball viscometer, and found to be 2800 poises at 40°C. The polymer solution (32% solids) was then conventionally dry-spun at a velocity of 733 m/min, and 20 denier, 2 -filament yarn was wound up on a cardboard tube . TABLE Appl. Appl. Appl. Appl. Comp. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. Stress at 100% 0.050 g/d 0.051 g/d 0.045 g/d 0.045 g/d 0.080 g/d Elongation Stress at 200% 0.096 g/d 0.112 g/d 0.093 g/d 0.101 g/d 0.174 g/d Elongation Elongation at 435% 400% 416% 407% 530% Break Strength at 1.27 g/d 1.08 g/d 1.14 g/d 0.94 g/d 1.12 g/d Break (Stress at 100% 0.039 0.047 0.039 0.048 0.071 elongation) / (Strength at break) (Stress at 200% 0.075 0.103 0.081 0.107 0.155 elongation) / (Strength at break) Following Durability Test Percent retention 95% 96% 100% 99% 83% of elongation Percent retention 86% 83% 89% 100% 32% of strength Following Yellowing Resistant Test Δb Value 4.0 4.6 4.8 6.0 22.9 As can be seen from the data in the Table, the polyurethane fibers of this invention have an unexpectedly, markedly enhanced durability and retention of strength when compared to prior art fibers and retain the good elongation properties of the prior art fibers. Because of these excellent properties, by using them alone or in combinations with various fibers, they can be utilized in various uses, such as a tightening material in a variety of textile products such as socks, stockings, circular knit fabrics, tricot fabrics, bathing suits, ski pants, work clothes, fire- resistant clothing, Western-style clothes, golf clothes, wet suits, brassieres, girdles and gloves. They can also be utilized as tightening material to prevent sanitary products such as disposable diapers from leaking and in waterproof materials; and such other uses as artificial bait, imitation flowers, wire insulation, wiping cloths, "copy cleaners," gaskets and the like.

Claims: Claims : 1. A polyestercarbonate-urethaneurea spandex consisting essentially of the reaction product of: a polycarbonate diol wherein said diol is the product of a reaction of a mixture of poly (hexane-1, 6- carbonate) diol and poly (ε-caprolactone) diol with a dialkylcarbonate ; a cyclic aliphatic diisocyanate; and a diamine chain extender. 2. The spandex of claim 1 wherein said diisocyanate is selected from the group consisting of 4,4' -methylenebis (cyclohexylisocyanate) , isophorone diisocyanate, methylcyclohexane-2 , 4-diiso-cyanate, methylcyclohexane-2 , 6-diisocyanate , cyclohexane-1 , 4- diisocyanate, hexahydroxylylene diisocyanate, and octahydro-1, 5 -naphthalene diisocyanate; and said diamine is selected from the group consisting of ethylenediamine, 1, 2-propanediamine, 1,3 -propane- diamine, hexamethylene diamine, 1, 4-cyclohexyldiamine and 1, 3-cyclohexyldiamine . 3. The spandex of claim 2 wherein said diisocyanate is 4 , 4 ' -methylenebis (cyclohexylisocyanate) and said diamine is ethylenediamine. 4. The spandex of claim 3 wherein said weight ratio of poly (hexane-1, 6-carbonate) diol to poly(ε- caprolactone) diol is from about 95:5 to 65:35. 5. The spandex of claim 3 wherein the molar ratio of said polycarbonate diol and the alicyclic diisocyanate is from about 1:1.3 to 1:3.0.

Inventors: ITO SHINGO, MATSUDA TOSHIKAZU, UMEZAWA MASAO, ITO, SHINGO, MATSUDA, TOSHIKAZU, UMEZAWA, MASAO
Applicants: DU PONT, DU PONT TORAY CO LTD, ITO SHINGO, MATSUDA TOSHIKAZU, UMEZAWA MASAO, DU PONT-TORAY COMPANY, LTD., E.I. DU PONT DE NEMOURS AND COMPANY, ITO, SHINGO, MATSUDA, TOSHIKAZU, UMEZAWA, MASAO
Application year: 1997
Main classification: C08G18
IPC codes: C08G18, D01F6