EP0456674A1 - Preforme contenant du pyrocarbone, son mode de fabrication et son utilisation - Google Patents

Preforme contenant du pyrocarbone, son mode de fabrication et son utilisation

Info

Publication number
EP0456674A1
EP0456674A1 EP90902227A EP90902227A EP0456674A1 EP 0456674 A1 EP0456674 A1 EP 0456674A1 EP 90902227 A EP90902227 A EP 90902227A EP 90902227 A EP90902227 A EP 90902227A EP 0456674 A1 EP0456674 A1 EP 0456674A1
Authority
EP
European Patent Office
Prior art keywords
pyrocarbon
carbon
temperatures
shaped body
coked
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90902227A
Other languages
German (de)
English (en)
Inventor
Ulrich Goetz
Martin Knoch
Helmut Reul
Günter RAU
Peter Grande
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
B Braun Melsungen AG
Original Assignee
B Braun Melsungen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by B Braun Melsungen AG filed Critical B Braun Melsungen AG
Publication of EP0456674A1 publication Critical patent/EP0456674A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/71—Ceramic products containing macroscopic reinforcing agents
    • C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
    • C04B35/80—Fibres, filaments, whiskers, platelets, or the like
    • C04B35/83—Carbon fibres in a carbon matrix
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/02—Inorganic materials
    • A61L27/08—Carbon ; Graphite
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/28—Materials for coating prostheses
    • A61L27/30—Inorganic materials
    • A61L27/303—Carbon
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/40—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
    • A61L27/44—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material having a macromolecular matrix
    • A61L27/443—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material having a macromolecular matrix with carbon fillers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/24—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
    • A61F2/2412—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body with soft flexible valve members, e.g. tissue valves shaped like natural valves
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
    • A61F2310/00005—The prosthesis being constructed from a particular material
    • A61F2310/00161—Carbon; Graphite
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
    • A61F2310/00389—The prosthesis being coated or covered with a particular material
    • A61F2310/00574—Coating or prosthesis-covering structure made of carbon, e.g. of pyrocarbon

Definitions

  • Shaped body containing pyrocarbon its production and use
  • the present invention relates to molded articles containing pyrocarbon, which have a low weight and at the same time have a high modulus of elasticity which can be influenced in a targeted manner and a very good surface quality.
  • the present invention further relates to the production of molded articles containing pyrocarbon and their use as exoprostheses, endoprostheses or orthoses, but in particular their use in single- or multi-winged heart valve prostheses or in heart valve components.
  • heart valve prostheses are already made from pyro-carbon.
  • This prior art either starts from isotropically deposited carbon or from anisotropically deposited carbon with a density of at least 70% of theoretical density.
  • These pyro Kohlen ⁇ material layers are deposited simultaneously silicides to reach t he necessary strength.
  • That isotropic carbon is preferably used for heart valve prostheses is due, among other things, to the platelet structure of the carbon, which tends to delaminate when anisotropic.
  • EP-A-0 055 406 describes a method for producing a valve ring for an artificial heart valve which consists essentially entirely of pyrocarbon and has an exactly shaped and dimensioned inner surface, this method consisting in the fact that a disc-shaped substrate is used which is the mirror image of the desired inner surface of this valve ring by using a material which is resistant to the pyrolytic decomposition temperature, heating said material to the desired temperature by moving into a zone containing a fluidized bed of fine particles, through which a carbon-containing atmosphere is passed in such a way that it precipitates to form essentially isotropic pyrocarbon, this being continued until a pyrocarbon layer of at least 250 ⁇ m thick is formed on the substrate has said coated substrate from Ab discrimination region removed and said substrate is removed in a like manner der ⁇ that said Pyro-carbon is affected not physically or chemically and the pyro carbon remains as an annular article a Has surface that is the mirror image of said substrate surface.
  • the pyrocarbon body obtained in this way has
  • US-A-3 526 005 relates to endoprostheses, in particular artificial heart valves, which are obtained by a substrate, for example artificial graphite, boron carbide, silicon carbide, tantalum, molybdenum, tungsten or mullite with an impenetrable isotropic pyro-carbon Coated layer that has an inert and antithrombogenic outer surface.
  • a substrate for example artificial graphite, boron carbide, silicon carbide, tantalum, molybdenum, tungsten or mullite with an impenetrable isotropic pyro-carbon Coated layer that has an inert and antithrombogenic outer surface.
  • the conditions under which the pyrolytic carbon is separated are set in such a way that the coefficient of thermal expansion of the pyrolytic carbon essentially corresponds to the coefficient of thermal expansion of the substrate and that a carbon body of high strength is obtained which is essential to the structural strength of the prosthetic composite article contributes.
  • the present invention has for its object to provide a molded article containing pyrocarbon which, with a comparable surface quality, has a lower average density and a higher modulus of elasticity than the molded article containing pyrocarbon known from the prior art. Both the mean density and the modulus of elasticity can be influenced in a targeted manner.
  • the present invention thus relates to a shaped body containing pyrocarbon, which is characterized in that
  • This molded body containing pyrocarbon is preferably an exoprosthesis, endoprosthesis or orthosis. Its use in endoprostheses is particularly preferred, in particular its use for single- or reverent heart valve prostheses or components for these heart valve prostheses. Due to the low average density of the endoprostheses of 1.6 g / cm ⁇ are in the human organism with moving components, eg. B. closing bodies of heart valve prostheses, the inertia forces to be overcome are lower. The reaction to the pulsating blood flow when opening and closing the heart valves is thus more delay-free. The impact load on the flap components and the surrounding tissue, in particular when closing, is reduced.
  • the pyrocarbon-containing molded articles according to the invention also have a higher modulus of elasticity and a higher structural strength than those of the prior art, which ensures that the endoprostheses can be used over a long period of time, that is, if possible for a lifetime, and the patient can be spared further operations.
  • the modulus of elasticity and the structural strength can be influenced within wide limits with the arrangement and the nature of the carbon fibers within the basic structure.
  • the pyrocarbon-containing moldings according to the invention have an equally dense surface, expressed as surface quality, so that human tissue cannot grow into the implant.
  • pyrocarbon-containing moldings can be produced with an average specific weight of less than 70% of the theoretical density and at the same time a dense surface with greater than 70% of the theoretical density.
  • housings or rings for prosthetic heart valves have also been made from monolithic, ie brittle, isotropic or anisotropic carbon in a fluidized bed or on a mandrel.
  • monolithic, ie brittle, isotropic or anisotropic carbon in a fluidized bed or on a mandrel.
  • a deformation of the housing or the ring is usually necessary for mounting the closing body.
  • the danger with monolithic materials is extremely great that microcracks and stresses are generated, which can lead to defects in long-term behavior.
  • the molded articles according to the invention containing pyrocarbon have an improved fracture mechanism, which is expressed in the improved Weibull modulus.
  • the shaped bodies according to the invention containing pyrocarbon preferably have an average specific weight of 1.2 to 1.3 g / c ⁇ .3.
  • the modulus of elasticity is preferably from 40,000 to 75,000 N / mm 2 .
  • the shaped articles containing pyrocarbon can preferably also contain metallic inclusions, for example silicon compounds, titanium compounds, molybdenum compounds or tungsten compounds, which are applied during the infiltration or sealing process.
  • the shaped bodies containing pyrocarbon preferably have an average specific weight of 40 to 60% of the theoretical density.
  • the present invention further relates to a process for the production of molded articles containing pyrocarbon, which is characterized in that they are obtained by
  • pyrocarbon-containing moldings having an anisotropic carbon layer are obtained when the sealing is carried out at temperatures of more than 1700 ° C.
  • the pyrocarbon-containing moldings also contain X-ray-opaque, mineral inserts made of silicon, titanium, molybdenum and tungsten compounds, for example the carbides or nitrides of these compounds.
  • the metal compounds are silicon carbide, titanium carbide, molybdenum carbide, tungsten carbide and silicon nitride, titanium nitride, molybdenum nitride.
  • Such deposits can be applied or applied to the pyrocarbon-containing molded body during the infiltration process (CVI) or the sealing process (CVD).
  • the method according to the invention is preferably used to produce moldings which can be used as endoprostheses, in particular single-leaf or multi-leaf heart valve prostheses or heart valve components.
  • the present invention describes the use of the shaped bodies according to the invention containing pyrocarbon as exoprostheses, endoprostheses or orthoses, but in particular the use of these shaped bodies as endoprostheses, which can advantageously be used in single- or multi-winged heart valve prostheses or in heart valve components.
  • Carbon fiber mats (satin fabric, Hitco) were crosslinked with a small amount of phenolic resin, cold-pressed and coked at 900 ° C. under a pressure of 50 bar for 24 hours.
  • the matrix was built up to a density of less than 70% of the theoretical density.
  • the product produced in this way had an elastic modulus of 42,000 N / mm 2 .
  • the surface quality R a of this sample was less than 1 ⁇ m after grinding and was therefore sufficient for implantation in human tissue.
  • bodies were produced according to Example 1 with a density of less than 50% of the theoretical density by coking and 72 hours of infiltration.
  • This substrate was then sealed at a temperature of 1450 ° C. at a pressure of 6 mbar for 24 h with a methane gas carrier gas stream of the above composition.
  • the process control resulted in dense, isotropic carbon layers of 500 ⁇ m in thickness.
  • the average density of the composite material obtained in this way was less than 70% of the theoretical density, that is to say a density of 1.3 g / cm 2.
  • the modulus of elasticity was 48,000 N / mm 2 .
  • Composite was at densities less than 70% of the theoretical density, i.e. a density of 1.5 g / cm -3.
  • the elastic modulus for this molded article containing pyrocarbon was 65,000 N / mm 2 .
  • a carbon fiber ring with an inner diameter of 24 mm, an outer diameter of 33 mm and a thickness of 5 mm was first coked as described in Example 1 and then infiltrates. This ring was then sealed at 1700 ° C. under the reaction conditions described in Example 3 in order to obtain a surface that was as dense as possible.
  • a molybdenum ring was embedded between the carbon fiber mats during the manufacture of the prepreg.
  • This molybdenum ring was also made by the phenolic resin crosslinked or later associated with pyrolytic carbon during the individual infiltrations.
  • this molded body is now produced in accordance with the processes described in Examples 1, 2 and 3, the metal reacts to form the metal carbide, which in turn leads to intensive interlocking between the pyrolytic carbon and the metal body.
  • the metal body, which is then present as a carbide, is visible by X-ray.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Veterinary Medicine (AREA)
  • Medicinal Chemistry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Transplantation (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Dermatology (AREA)
  • Composite Materials (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Prostheses (AREA)
  • Materials For Medical Uses (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

Préformé contenant du pyrocarbone. Son poids est peu élevé, il présente un module d'élasticité relativement élevé et une excellente qualité de surface. On l'obtient de la façon suivante: on cokéfie des fibres de carbone à une température comprise entre 800 et 1200°C, on infiltre ensuite cette masse cokéfiée avec du pyrocarbone à une température de 1100° C jusqu'à obtenir une densité représentant au maximum 70 % de la densité théorique, en on scelle enfin le produit ainsi obtenu avec une couche de pyrocarbone à une température comprise entre 1300 et 1800° C. Cette invention porte en outre sur la fabrication de préformés contenant ces pyrocarbones et sur leur utilisation en tant qu'exoprothèses, endoprothèses et orthèses, en particulier en tant que prothèses de valvules cardiaques à un seul ou plusieurs pans et en tant que constituants de valvules cardiaques.
EP90902227A 1989-02-01 1990-01-30 Preforme contenant du pyrocarbone, son mode de fabrication et son utilisation Withdrawn EP0456674A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3902856A DE3902856A1 (de) 1989-02-01 1989-02-01 Pyro-kohlenstoff enthaltender formkoerper, seine herstellung und verwendung
DE3902856 1989-02-01

Publications (1)

Publication Number Publication Date
EP0456674A1 true EP0456674A1 (fr) 1991-11-21

Family

ID=6373160

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90902227A Withdrawn EP0456674A1 (fr) 1989-02-01 1990-01-30 Preforme contenant du pyrocarbone, son mode de fabrication et son utilisation

Country Status (4)

Country Link
EP (1) EP0456674A1 (fr)
JP (1) JPH04503050A (fr)
DE (1) DE3902856A1 (fr)
WO (1) WO1990008745A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4142261A1 (de) * 1991-12-20 1993-06-24 Man Technologie Gmbh Verfahren und vorrichtung zur herstellung von verbundbauteilen
NL1004867C2 (nl) * 1996-12-20 1998-06-23 Tno Met vezels versterkt bio-keramisch composietmateriaal.
US6248392B1 (en) 1996-12-20 2001-06-19 Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Ondersoek Tno Method for manufacturing a fiber-reinforced bioactive ceramic implant
DE10143874A1 (de) * 2001-09-07 2003-03-27 Sintec Keramik Gmbh & Co Kg Knochen-Implantat und Verfahren zum Herstellen desselben
DE10157782A1 (de) * 2001-11-28 2003-06-12 Schunk Kohlenstofftechnik Gmbh Implantat sowie Verfahren zum Herstellen eines solchen
DE10322182A1 (de) * 2003-05-16 2004-12-02 Blue Membranes Gmbh Verfahren zur Herstellung von porösem, kohlenstoffbasiertem Material
AU2004238517A1 (en) * 2003-05-16 2004-11-25 Cinvention Ag Method for coating substrates with a carbon-based material
EP1626752A2 (fr) * 2003-05-16 2006-02-22 Blue Membranes GmbH Implants medicaux revetus de maniere biocompatible
US9254349B2 (en) * 2009-02-09 2016-02-09 St. Jude Medical, Inc. Enhancing biocompatibility of a medical device

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3526005A (en) * 1967-06-29 1970-09-01 Gulf General Atomic Inc Method of preparing an intravascular defect by implanting a pyrolytic carbon coated prosthesis
US3895084A (en) * 1972-03-28 1975-07-15 Ducommun Inc Fiber reinforced composite product
US4276658A (en) * 1977-11-02 1981-07-07 St. Jude Medical, Inc. Heart valve prosthesis
EP0055406B1 (fr) * 1980-12-29 1985-03-27 Carbomedics Inc. Procédé pour la production d'éléments de prothèses en graphite pyrolytique
FR2521127B1 (fr) * 1982-02-09 1986-04-04 Europ Propulsion Procede et dispositif pour la realisation de parois deformables elastiquement en fibres de carbone

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9008745A1 *

Also Published As

Publication number Publication date
DE3902856A1 (de) 1990-08-02
WO1990008745A1 (fr) 1990-08-09
JPH04503050A (ja) 1992-06-04

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