EP0177552B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
The preparation of ultra high molecular weight polyethylene morphologies of totally fused particles with superior mechanical performance
Assignee: Individual
•
Filing: 1985-03-05
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Granted: 1992-05-27
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Expires: 2005-03-05
Abstract
Abstract An isotropic semicrystalline morphology of ultra-high-molecular-weight polyethylene and a method of making it. An original powder stock or a partially fused, melt-crystallized stock having a granular memory, is heated to a temperature at which the stock fuses completely to form a homogeneous melt which loses memory of the granular structure of the original stock. The resultant melt is cooled to ambient temperatures under compression to provide a novel homogeneous isotropic semicrystalline morphology. An anisotropic morphology of ultra-high-molecular-weight polyethylene may then be made by solid-state deforming that semicrystalline morphology at a temperature near but below its crystalline melting point at a deformation ratio of about 5 to 8.
Inventors
- 👤 Anagnostis E. Zachariades
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 23:38
CPC Classifications
B; B29; B29C; B29C43/00; B29C43/003; B29C43/32; B29C43/52; B29C55/00; B29C55/02; B29C55/18; B29C67/00; B29C67/24; A; A61; A61F; A61F2210/00; A61F2210/0014; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/0658; B29K2023/0683; B29K2105/00; B29K2105/25; B29K2105/251; B29K2995/00; B29K2995/0037; B29K2995/0041; B29K2995/0045; B29K2995/0088; B29L; B29L2031/00; B29L2031/753; B29L2031/7532; Y; Y10; Y10S; Y10S528/00; Y10S528/92; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
100 words
A method for making an ultra-high-molecular-weight polyethylene (UHMW PE) having an isotropic semi-crystalline morphology comprising: heating an original powder stock or a partially fused melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having granular memory to a temperature of 220-320° C in the absence of oxygen to fuse the stock completely to form a homogeneous melt which loses memory of its former granular structure, and cooling the resultant melt to ambient temperatures under compression to provide a UHMW PE having a homogeneous isotropic semi-crystalline morphology which has no memory of the granular nature of the original stock.
Claim 2
Dependent Claim
18 words
The method of claim 1 wherein the heating step comprises heating at 320° C for about 10 minutes.
Claim 3
Independent Claim
134 words
A method for making an ultra-high-molecular-weight polyethylene (UHMW PE) having an isotropic homogeneous semicrystalline morphology comprising: heating an original powder stock or a partially fused melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having granular memory, at a temperature of 320° C in the absence of oxygen at a pressure of about 20-50 MPa for about ten minutes, then at about 150° C placing the material under a pressure of about 70-280 MPa for another ten minutes to provide a melt in which the stock fuses completely and loses memory of its former granular structure, and cooling the resultant material to ambient temperature under a pressure of about 20 MPa to give a UHMW PE having a semicrystalline morphology which has no memory of the granular nature of the original stock.
Claim 4
Independent Claim
122 words
A method for making an ultra-high-molecular-weight polyethylene (UHMW PE) having an anisotropic morphology comprising: heating an original powder stock or a partially fused melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having granular memory to a temperature between 220 and 320° C in the absence of oxygen to fuse the stock completely and lose memory of its original granular structure, cooling the resultant material to ambient temperatures under compression to provide a UHMW PE having an initial homogeneous isotropic semicrystalline morphology which has no memory of the granular nature of the original stock, and solid-state deforming that semicrystalline UHMW PE at a temperature near but below its crystalline melting point at a deformation ratio of about 5 to 8.
Claim 5
Dependent Claim
14 words
The method of claim 4 wherein the temperature of deformation is about 130° C.
Claim 6
Dependent Claim
18 words
The method of claim 4 wherein the heating is accompanied by a compression pressure of about 20-50 MPa.
Claim 7
Dependent Claim
22 words
The method of claim 6 wherein the heating step also includes heat at 150° C under a pressure of about 70-280 MPa.
Claim 8
Dependent Claim
15 words
The method of claim 4 wherein the deforming step includes drawing at least five times.
Claim 9
Independent Claim
160 words
A method for making an ultra-high-molecular-weight polyethylene (UHMW PE) having an anisotropic morphology comprising: heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having granular memory, at a temperature of 320° C in the absence of oxygen at a compression pressure of about 20-50 MPa for about ten minutes, then at about 150° C placing the material under a compression pressure of about 70-280 MPa for another ten minutes to provide a melt in which the stock fuses completely and loses memory of its former granular structure, cooling the resultant material to ambient temperature under a compression pressure of about 20 MPa to give a UHMW PE having a semicrystalline morphology which has no memory of the granular nature of the original stock, and extruding the semicrystalline product through an extrusion rolling die at a temperature of about 130° C at a deformation ratio of about 5 to 8.
Claim 10
Independent Claim
154 words
A method for making an ultra-high-molecular-weight polyethylene having an anisotropic morphology comprising: heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having a granular memory, at a temperature of 320° C in the absence of oxygen at a compression pressure of about 20-50 MPa for about ten minutes, then at about 150° C placing the material under a compression pressure of about 70-280 MPa for another ten minutes to provide a melt in which the stock fuses completely and loses memory of its former granular structure, cooling the resultant material to ambient temperatures under a compression pressure of about 20 MPa to give a UHMW PE having a semicrystalline morphology which has no memory of the granular nature of the original stock, and drawing the semicrystalline product at a temperature of about 130° C at a deformation ratio of about 5 to 8.
Claim 11
Dependent Claim
29 words
An ultra-high-molecular-weight polyethylene (UHMW PE) having isotropic semicrystalline morphology obtained from a completely fused UHMW PE as defined by ASTM D 4020-81 without any memory of a granular structure.
Claim 12
Dependent Claim
29 words
An ultra-high-molecular-weight polyethylene (UHMW PE) having isotropic semi-crystalline morphology obtained from a homogeneous melt of UHMW PE as defined by ASTM D 4020-81 without the aid of radiation dopants.
Claim 13
Dependent Claim
41 words
A homogeneous melt crystallized ultra-high molecular-weight polyethylene having an isotropic semicrystalline morphology with a molecular network structure and physical entanglements obtained from an UHMW PE as defined by ASTM D 4020-81 without the aid of radiation cross-linking and chemical cross-linking agents.
Claim 14
Dependent Claim
109 words
An ultra-high-molecular-weight polyethylene (UHMW PE) useful for the fabrication of an orthopaedic prosthetic device or a tendon having a molecular weight of several millions and made by first heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having a granular memory, to a temperature between 220 and 320° C in the absence of oxygen to fuse the stock completely and lose memory of its former granular structure, and then cooling the resultant material to ambient temperatures under compression load to give a UHMW PE having a semicrystalline morphology without memory of the granular nature of the original stock.
Claim 15
Dependent Claim
54 words
An ultra-high-molecular-weight polyethylene (UHMW PE) having anisotropic morphology comprising: a solid-state deformed UHMW PE of UHMW PE as defined by ASTM D 4020-81 having semicrystalline morphology and having no memory of a granular nature, deformed at a temperature near but below its crystalline melting point at a deformation ratio of about 5 to 8.
Claim 16
Dependent Claim
20 words
The anisotropic ultra-high-molecular-weight polyethylene of claim 15 wherein the solid state deformed UHMW PE has a filamentary or ribbon-like morphology.
Claim 17
Dependent Claim
27 words
The anisotropic ultra-high-molecular-weight polyethylene of claim 16 wherein the filamentary or ribbon-like products exhibit resistance to fibrillation without the aid of radiation cross-linking or chemical cross-linking agents.
Claim 18
Dependent Claim
126 words
An ultra-high-molecular-weight polyethylene (UHMW PE) useful for tendon fabrication, having a molecular weight of several millions and made by first heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having a granular memory, to a temperature between 220 and 320° C in the absence of oxygen to fuse the stock completely and lose memory of its former granular structure, then cooling the resultant material to ambient temperatures under compression load to give a UHMW PE having a semicrystalline morphology without memory of the granular nature of the original stock, and then extruding the semicrystalline product through an extrusion rolling die at a temperature of about 130° C and at a deformation ratio of about 5-8.
Claim 19
Dependent Claim
121 words
An ultra-high-molecular-weight polyethylene (UHMW PE) useful for tendon fabrication, having a molecular weight of several millions and made by first heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having a granular memory, to a temperature between 220 and 320° C in the absence of oxygen to fuse the stock completely and lose memory of its former granular structure, then cooling the resultant material to ambient temperatures under compression load to give a UHMW PE having a semicrystalline morphology without memory of the granular nature of the original stock, and then drawing the semicrystalline product at a temperature of about 130° C and at a deformation ratio of about 5-8.
Claim 20
Dependent Claim
126 words
An ultra-high-molecular-weight polyethylene (UHMW PE) useful for the fabrication of an orthopaedic prosthetic device, having a molecular weight of several millions and made by first heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having a granular memory, to a temperature between 220 and 320°C in the absence of oxygen to fuse the stock completely and lose memory of its former granular structure, then cooling the resultant material to ambient temperatures under compresssion load to give a UHMW PE having a semicrystalline morphology without memory of the granular nature of the original stock, and then deforming the semicrystalline product at a temperature of about 130°C and at a deformation ratio of about 5 - 8.
Claim 21
Independent Claim
152 words
A method for making an ultra-high-molecular-weight polyethylene (UHMW PE) having an isotropic homogeneous semicrystalline morphology comprising: heating an original powder stock or a partially fused melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having granular memory, to a temperature between 220° C and 320° C in the absence of oxygen at a pressure of about 20-50 MPa to fuse the stock completely to form a homogeneous melt which loses memory of its former granular structure, and then at about 150° C placing the material under a pressure of about 70-280 MPa for another ten minutes to provide a melt in which the stock fuses completely and loses memory of its former granular structure, and cooling the resultant material to ambient temperature under a pressure of about 20 MPa to give a UHMW PE having a semicrystalline morphology which has no memory of the granular nature of the original stock.
Claim 22
Independent Claim
178 words
A method for making an ultra-high-molecular-weight polyethylene (UHMW PE) having an anisotropic morphology comprising: heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having granular memory, to a temperature between 220° C and 320° C in the absence of oxygen at a compression pressure of about 20-50 MPa to fuse the stock completely to form a homogeneous melt which loses memory of its former granular structure, and then at about 150° C placing the material under a compression pressure of about 70-280 MPa for another ten minutes to provide a melt in which the stock fuses completely and loses memory of its former granular structure, cooling the resultant material to ambient temperature under a compression pressure of about 20 MPa to give a UHMW PE having a semicrystalline morphology which has no memory of the granular nature of the original stock, and extruding the semicrystalline product through an extrusion rolling die at a temperature of about 130° C at a deformation ratio of about 5 to 8.
Claim 23
Independent Claim
172 words
A method for making an ultra-high-molecular-weight polyethylene having an anisotropic morphology comprising: heating an original powder stock or a partially fused, melt-crystallized stock of UHMW PE as defined by ASTM D 4020-81 having a granular memory, to a temperature between 220° C and 320° C in the absence of oxygen at a compression pressure of about 20-50 MPa to fuse the stock completely to form a homogeneous melt which loses memory of its former granular structure, and then at about 150° C placing the material under a compression pressure of about 70-280 MPa for another ten minutes to provide a melt in which the stock fuses completely and loses memory of its former granular structure, cooling the resultant material to ambient temperatures under a compression pressure of about 20 MPa to give a UHMW PE having a semicrystalline morphology which has no memory of the granular nature of the original stock, and drawing the semicrystalline product at a temperature of about 130° C at a deformation ratio of about 5 to 8.
References Cited (Backward Citations)
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