US4655769A
Expired / Lapsed
US
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Ultra-high-molecular-weight polyethylene products including vascular prosthesis devices and methods relating thereto and employing pseudo-gel states
Assignee: International Business Machines Corp
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Filing: 1985-12-18
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Granted: 1987-04-07
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Expires: 2005-12-18
Abstract
Abstract A pseudo-gel comprising a suitable solvent in an amount of 99 to 90 percent by weight and an ultra-high-molecular-weight polyethylene in an amount of 1 to 10 percent by weight, said polyethylene being a semicrystalline network with adjustable crystalline morphology comprising randomly dispersed and oriented chain-folded single crystals, stacks of single crystals, spherulite crystals, and extended-chain shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 mu m. Also, the semicrystalline ultra-high molecular-weight polyethylene obtained by removal of said solvent from the pseudo-gel. Further, a method for making the pseudo-gel and the ultra-high-molecular-weight polyethylene product.
Inventors
- 👤 Anagnostis E. Zachariades
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:04
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; A; A61; A61L; A61L27/00; A61L27/14; A61L27/16; A61L27/50; A61L27/507; B; B29; B29C; B29C43/00; B29C43/02; B29C43/20; B29C43/203; B29C55/00; B29C55/005; B29K; B29K2023/00; B29K2023/04; B29K2023/06; C08J2201/00; C08J2201/04; C08J2201/052; C08J2201/054; C08J2201/0542; C08J2201/0543; C08J2201/0545; C08J2201/0546; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/06
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
42 words
A tube of ultra-high-molecular-weight polyethylene semicrystalline morphology useful for vascular prostheses and having a Young's modulus of at least 3 GPa obtained by wrapping an ultra-high-molecular-weight polyethylene pseudo-gel on a mandrel, extracting the solvent with more volatile solvent and evaporating volatile solvent.
Claim 2
Dependent Claim
42 words
A tube of ultra-high-molecular-weight polyethylene semicrystalline morphology useful for vascular prostheses and having a Young's modulus of at least 3 GPa obtained by wrapping an ultra-high-molecular-weight polyethylene pseudo-gel on a mandrel, extracting the solvent with more volatile solvent and evaporating volatile solvent.
Claim 3
Dependent Claim
18 words
The tube of claim 1 in which the porosity is adjustable over the range of 0.2% to 90%.
Claim 4
Independent Claim
75 words
A method for making an ultra-high-molecular-weight polyethylene product for use in vascular prostheses and the like, comprising, dissolving under slow-stirring conditions ultra-high-molecular-weight polyethylene in a solvent at an elevated temperature in the range of 140°-170° C., cooling the solution at a rate less than 20° C. per minute to a temperature at which polymer crystals grow into an intercrystalline network that produces a pseudo-gel state, and extracting the solvent to produce a semicrystalline porous morphology.
Claim 5
Independent Claim
75 words
A method for making an ultra-high-molecular-weight polyethylene product for use in vascular prostheses and the like, comprising, dissolving under slow-stirring conditions ultra-high-molecular-weight polyethylene in a solvent at an elevated temperature in the range of 140°-170° C., cooling the solution at a rate less than 20° C. per minute to a temperature at which polymer crystals grow into an intercrystalline network that produces a pseudo-gel state, and extracting the solvent to produce a semicrystalline porous morphology.
Claim 6
Dependent Claim
15 words
The method of claim 3 wherein the cooling step is done under non-isothermal, quiescent conditions.
Claim 7
Dependent Claim
46 words
The method of claim 4 followed by drawing the semicrystalline morphology resulting from the extracting step, at a draw ratio of at least 5 and at a temperature in the range from ambient temperature to a temperature not exceeding the melting point of said semicrystalline morphology.
Claim 8
Dependent Claim
18 words
The method of claim 4, comprising, between the cooling and extracting steps, the step of compressing the gel.
Claim 9
Dependent Claim
15 words
The method of claim 3 wherein the cooling step is done under isothermal, non-quiescent conditions.
Claim 10
Dependent Claim
15 words
The method of claim 3 wherein the cooling step is done under isothermal, quiescent conditions.
Claim 11
Independent Claim
89 words
A method of making an ultra-high-molecular-weight polyethylene product for use in vascular prostheses and the like, comprising, dissolving, under slow-stirring conditions of about 60-600 r.p.m., ultra-high-molecular-weight polyethylene in a non-volatile solvent at an elevated temperature in the range of 140°-170° C., cooling the solution at a rate less than 20° C. per minute to a temperature in the vicinity of 120° to 125° C. at which polymer crystals grow into an intercrystalline network that produces a pseudo-gel state, and extracting the non-volatile solvent to produce a semi-crystalline porous morphology.
Claim 12
Independent Claim
89 words
A method of making an ultra-high-molecular-weight polyethylene product for use in vascular prostheses and the like, comprising, dissolving, under slow-stirring conditions of about 60-600 r.p.m., ultra-high-molecular-weight polyethylene in a non-volatile solvent at an elevated temperature in the range of 140°-170° C., cooling the solution at a rate less than 20° C. per minute to a temperature in the vicinity of 120° to 125° C. at which polymer crystals grow into an intercrystalline network that produces a pseudo-gel state, and extracting the non-volatile solvent to produce a semi-crystalline porous morphology.
Claim 13
Dependent Claim
29 words
The method of claim 9 wherein the cooling step is done under non-isothermal, quiescent conditions, at a cooling rate of about 5° to 20° C. per minute, without stirring.
Claim 14
Dependent Claim
39 words
The method of claim 10 followed by drawing the resulting product at a temerature no lower than ambient and no higher than the melting point of the semicrystalline porous morphology and at a draw ratio of at least 5.
Claim 15
Dependent Claim
22 words
The method of claim 10, comprising, between the cooling and extracting steps, compressing the gel between plates at 100° to 160° C.
Claim 16
Dependent Claim
27 words
The method of claim 9 wherein the cooling step is done under isothermal, non-quiescent conditions at a cooling rate of about 0.1° C. per minute, while stirring.
Claim 17
Dependent Claim
27 words
The method of claim 9 wherein the cooling step is done under isothermal, quiescent conditions at a cooling rate of about 0.1° C. per minute, without stirring.
Claim 18
Independent Claim
50 words
A method for making a tubular profile of ultra-high-molecular-weight polyethylene with adjustable wall thickness, comprising the successive steps of wrapping an ultra-high-molecular-weight polyethylene pseudo-gel containing nonvolatile solvent on a mandrel, extracting the solvent from the pseudo-gel with a more volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 19
Independent Claim
50 words
A method for making a tubular profile of ultra-high-molecular-weight polyethylene with adjustable wall thickness, comprising the successive steps of wrapping an ultra-high-molecular-weight polyethylene pseudo-gel containing nonvolatile solvent on a mandrel, extracting the solvent from the pseudo-gel with a more volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 20
Dependent Claim
28 words
The method of claim 15, comprising making an anisotropic ultra-high-molecular-weight polyethylene tubular structure by following the evaporating steps with the step of stretching the tube on the mandrel.
Claim 21
Dependent Claim
29 words
The method of claim 16 in which the temperature of stretching is from ambient temperature to the melting point of the semicrystalline porous morphology obtained after the evaporating step.
Claim 22
Dependent Claim
14 words
The method of claim 16 in which the draw ratio is at least 5×.
Claim 23
Independent Claim
90 words
A method for making a tubular profile of ultra-high-molecular-weight polyethylene with adjustable wall thickness, comprising the steps of: dissolving said ultra-high-molecular-weight polyethylene in non-volatile solvent at an elevated temperature in the range of 140°-170° C., cooling the solution at a rate of less than 20° C. per minute to a temperature at which polymer crystals grow into an intercrystalline network that provides a pseudo-gel, wrapping the gel around a mandrel, extracting the non-volatile solvent from the gel with a volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 24
Independent Claim
90 words
A method for making a tubular profile of ultra-high-molecular-weight polyethylene with adjustable wall thickness, comprising the steps of: dissolving said ultra-high-molecular-weight polyethylene in non-volatile solvent at an elevated temperature in the range of 140°-170° C., cooling the solution at a rate of less than 20° C. per minute to a temperature at which polymer crystals grow into an intercrystalline network that provides a pseudo-gel, wrapping the gel around a mandrel, extracting the non-volatile solvent from the gel with a volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 25
Dependent Claim
30 words
The method of claim 19 followed by stretching the tube on the mandrel at a temperature from ambient to 135° C. and at a draw ratio of at least 5×.
Claim 26
Independent Claim
66 words
A method for making an ultra-high-molecular-weight polymer product for use in vascular prostheses and the like, comprising, slowly dissolving ultra-high-molecular-weight polymer in a solvent at an elevated temperature, cooling the solution at a rate below 20° C. per minute to a temperature at which polymer crystals grow into an intercrystalline network that produces a pseudo-gel state, and extracting the solvent to produce a semi-crystalline porous morphology.
Claim 27
Independent Claim
66 words
A method for making an ultra-high-molecular-weight polymer product for use in vascular prostheses and the like, comprising, slowly dissolving ultra-high-molecular-weight polymer in a solvent at an elevated temperature, cooling the solution at a rate below 20° C. per minute to a temperature at which polymer crystals grow into an intercrystalline network that produces a pseudo-gel state, and extracting the solvent to produce a semi-crystalline porous morphology.
Claim 28
Dependent Claim
15 words
The method of claim 21 wherein the cooling step is done under non-isothermal, quiescent conditions.
Claim 29
Dependent Claim
46 words
The method of claim 22 followed by drawing the semicrystalline morphology resulting from the extracting step, at a draw ratio of at least 5 and at a temperature in the range from ambient temperature to a temperature not exceeding the melting point of said semicrystalline morphology.
Claim 30
Dependent Claim
18 words
The method of claim 22, comprising, between the cooling and extracting steps, the step of compressing the gel.
Claim 31
Dependent Claim
15 words
The method of claim 21 wherein the cooling step is done under isothermal, non-quiescent conditions.
Claim 32
Dependent Claim
15 words
The method of claim 21 wherein the cooling step is done under isothermal, quiescent conditions.
Claim 33
Independent Claim
50 words
A method for making a tubular profile of ultra-high-molecular-weight polymer with adjustable wall thickness, comprising the successive steps of wrapping an ultra-high-molecular-weight polymer pseudo-gel containing nonvolatile solvent on a mandrel, extracting the solvent from the pseudo-gel with a more volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 34
Independent Claim
50 words
A method for making a tubular profile of ultra-high-molecular-weight polymer with adjustable wall thickness, comprising the successive steps of wrapping an ultra-high-molecular-weight polymer pseudo-gel containing nonvolatile solvent on a mandrel, extracting the solvent from the pseudo-gel with a more volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 35
Dependent Claim
28 words
The method of claim 27, comprising making an anisotropic ultra-high-molecular-weight polyethylene tubular structure by following the evaporating steps with the step of stretching the tube on the mandrel.
Claim 36
Dependent Claim
29 words
The method of claim 28 in which the temperature of stretching is from ambient temperature to the melting point of the semicrystalline porous morphology obtained after the evaporating step.
Claim 37
Dependent Claim
14 words
The method of claim 28 in which the draw ratio is at least 5×.
Claim 38
Independent Claim
89 words
A method for making a tubular profile of ultra-high-molecular-weight polyethylene with adjustable wall thickness, comprising the steps of: slowly dissolving said ultra-high-molecular-weight polyethylene in non-volatile solvent at an elevated temperature, in the range of 140°-170° C., cooling the solution at a rate lower than 20° C. per minute to temperature at which polymer crystals grow into an intercrystalline network that provides a pseudo-gel, wrapping the gel around a mandrel, extracting the non-volatile solvent from the gel with a volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 39
Independent Claim
89 words
A method for making a tubular profile of ultra-high-molecular-weight polyethylene with adjustable wall thickness, comprising the steps of: slowly dissolving said ultra-high-molecular-weight polyethylene in non-volatile solvent at an elevated temperature, in the range of 140°-170° C., cooling the solution at a rate lower than 20° C. per minute to temperature at which polymer crystals grow into an intercrystalline network that provides a pseudo-gel, wrapping the gel around a mandrel, extracting the non-volatile solvent from the gel with a volatile solvent, and evaporating the volatile solvent from the tubular profile.
Claim 40
Dependent Claim
72 words
A pseudo-gel comprising a suitable solvent in an amount of 99 to 90 percent by weight and an ultra-high-molecular-weight polyethylene in an amount of 1 to 10 percent by weight, said polyethylene being a semicrystalline network with adjustable crystalline morphology comprising randomly dispersed and oriented chain-folded single crystals, stacks of single crystals, spherulite crystals, and extended-chain shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm.
Claim 41
Dependent Claim
72 words
A pseudo-gel comprising a suitable solvent in an amount of 99 to 90 percent by weight and an ultra-high-molecular-weight polyethylene in an amount of 1 to 10 percent by weight, said polyethylene being a semicrystalline network with adjustable crystalline morphology comprising randomly dispersed and oriented chain-folded single crystals, stacks of single crystals, spherulite crystals, and extended-chain shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm.
Claim 42
Dependent Claim
17 words
The semicrystalline ultra-high molecular-weight polyethylene obtained by removal of said solvent from the pseudo-gel of claim 32.
Claim 43
Dependent Claim
94 words
A semicrystalline morphology of ultra-high-molecular-weight polyethylene comprising randomly dispersed and oriented single crystals, stacks of single crystals, spherulitic crystals, and shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm, a melting point of 125°-140° C., measured at a heating rate of 5° C./min., a crystallinity of about 70%, measured on the basis that the heat of fusion of a perfect polyethylene crystal is 293 J/g., and a porosity from about 50 to 90%, measured on the basis that the density of polyethylene is 960 Kg/m 3 .
Claim 44
Dependent Claim
94 words
A semicrystalline morphology of ultra-high-molecular-weight polyethylene comprising randomly dispersed and oriented single crystals, stacks of single crystals, spherulitic crystals, and shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm, a melting point of 125°-140° C., measured at a heating rate of 5° C./min., a crystallinity of about 70%, measured on the basis that the heat of fusion of a perfect polyethylene crystal is 293 J/g., and a porosity from about 50 to 90%, measured on the basis that the density of polyethylene is 960 Kg/m 3 .
Claim 45
Dependent Claim
72 words
A pseudo-gel comprising a suitable solvent in an amount of 99 to 80 percent by weight and an ultra-high-molecular-weight polymer in an amount of 1 to 20 percent by weight, said polymer being a semicrystalline network with adjustable crystalline morphology comprising randomly dispersed and oriented chain-folded single crystals, stacks of single crystals, spherulite crystals, and extended-chain shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm.
Claim 46
Dependent Claim
72 words
A pseudo-gel comprising a suitable solvent in an amount of 99 to 80 percent by weight and an ultra-high-molecular-weight polymer in an amount of 1 to 20 percent by weight, said polymer being a semicrystalline network with adjustable crystalline morphology comprising randomly dispersed and oriented chain-folded single crystals, stacks of single crystals, spherulite crystals, and extended-chain shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm.
Claim 47
Dependent Claim
17 words
The semicrystalline ultra-high molecular-weight polymer obtained by removal of said solvent from the pseudo-gel of claim 35.
Claim 48
Dependent Claim
63 words
A semicrystalline morphology of ultra-high-molecular-weight polymer comprising randomly dispersed and oriented single crystals, stacks of single crystals, spherulitic crystals, and shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm., a melting point of 125°-270° C., depending on the particular polymer, measured at a heating rate of 5° C./min., a crystallinity of about 50% to about 75%.
Claim 49
Dependent Claim
63 words
A semicrystalline morphology of ultra-high-molecular-weight polymer comprising randomly dispersed and oriented single crystals, stacks of single crystals, spherulitic crystals, and shish-kebab-type of fibrils with lengths up to a few millimeters and widths up to 20 μm., a melting point of 125°-270° C., depending on the particular polymer, measured at a heating rate of 5° C./min., a crystallinity of about 50% to about 75%.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |