WO2006013536A1 - Recuit de polymères réticulés par rayonnement - Google Patents
Recuit de polymères réticulés par rayonnement Download PDFInfo
- Publication number
- WO2006013536A1 WO2006013536A1 PCT/IB2005/052505 IB2005052505W WO2006013536A1 WO 2006013536 A1 WO2006013536 A1 WO 2006013536A1 IB 2005052505 W IB2005052505 W IB 2005052505W WO 2006013536 A1 WO2006013536 A1 WO 2006013536A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- artefact
- container
- polymer
- unsaturated hydrocarbon
- annealing
- Prior art date
Links
- 238000000137 annealing Methods 0.000 title claims abstract description 41
- 230000005855 radiation Effects 0.000 title claims abstract description 34
- 229920006037 cross link polymer Polymers 0.000 title description 7
- 238000000034 method Methods 0.000 claims abstract description 52
- 229920000642 polymer Polymers 0.000 claims abstract description 47
- 238000004132 cross linking Methods 0.000 claims abstract description 27
- 229930195735 unsaturated hydrocarbon Natural products 0.000 claims abstract description 27
- 239000007943 implant Substances 0.000 claims abstract description 15
- 239000007789 gas Substances 0.000 claims description 37
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 19
- 239000001301 oxygen Substances 0.000 claims description 19
- 229910052760 oxygen Inorganic materials 0.000 claims description 19
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 claims description 14
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 claims description 14
- 150000001336 alkenes Chemical class 0.000 claims description 10
- -1 ethylene, propylene, butylene Chemical group 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 229920010741 Ultra High Molecular Weight Polyethylene (UHMWPE) Polymers 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 5
- 238000007789 sealing Methods 0.000 claims description 5
- 150000001345 alkine derivatives Chemical class 0.000 claims description 4
- 230000003028 elevating effect Effects 0.000 claims description 4
- 230000008878 coupling Effects 0.000 claims description 3
- 238000010168 coupling process Methods 0.000 claims description 3
- 238000005859 coupling reaction Methods 0.000 claims description 3
- 150000003254 radicals Chemical class 0.000 description 32
- 239000004699 Ultra-high molecular weight polyethylene Substances 0.000 description 17
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 description 17
- 239000000463 material Substances 0.000 description 9
- 238000010525 oxidative degradation reaction Methods 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000004698 Polyethylene Substances 0.000 description 3
- 231100000987 absorbed dose Toxicity 0.000 description 3
- 238000001727 in vivo Methods 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 239000003431 cross linking reagent Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 239000004700 high-density polyethylene Substances 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 230000000155 isotopic effect Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229920006798 HMWPE Polymers 0.000 description 1
- 239000004705 High-molecular-weight polyethylene Substances 0.000 description 1
- 208000003076 Osteolysis Diseases 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 210000001124 body fluid Anatomy 0.000 description 1
- 239000010839 body fluid Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000003708 edge detection Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 208000029791 lytic metastatic bone lesion Diseases 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 238000007348 radical reaction Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Classifications
-
- 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
- A61L27/14—Macromolecular materials
- A61L27/16—Macromolecular materials obtained by reactions only involving carbon-to-carbon unsaturated bonds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/06—Polyethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2312/00—Crosslinking
- C08L2312/06—Crosslinking by radiation
Definitions
- This invention relates to a method of reducing residual chemically reactive free radicals in polymeric artefacts following the radiation-induced crosslinking thereof. This invention further relates to radiation-induced crossl inked artefacts treated by such a method.
- the residual free radicals can either be in the radiation crosslinked feedstock UHMWPE from which the medical device is to be made, or in the final medical device made from the UHMWPE when the medical device is radiation crosslinked following the manufacture thereof from the non-crosslinked feedstock UHMWPE.
- the radiation-induced free radicals are mainly used in effecting the crosslinking of the UHMWPE, the limited free radical mobility in the polymeric matrix results in residual iong-lived free radicals in the irradiated polymer following the irradiation crosslinking process.
- the long-lived free radicals can remain entrapped in the polymer matrix of the irradiated polymer for relatively long periods.
- Such long-lived residual free radicals react with oxygen in the air or the surrounding biological tissues or fluids, resulting in the oxidation of the irradiated polymer surface. It is known that such an oxidation of the polymer surface is detrimental to the wear characteristics of the artefact made from such radiation crosslinked polymers.
- the artefact is in the form of a medical implant or prosthesis, such a post- irradiation oxidative degradation of the polymer surface in an oxygen- containing environment can take place months after the crosslinking of the polymer and indeed even after implantation thereof in a patient, impairing the long-term wear characteristics of such an orthopaedic medical device.
- the main disadvantages of this annealing method are the relatively long period of time (144 hours) and high temperatures (135 0 C) required to anneal the implant and the negative effect which the annealing process could have on the elastic modulus, the yield stress and the ultimate stress of the polymer, which in turn negatively impacts on the mechanical properties of the UHMWPE.
- a method of manufacturing an artefact including the steps of: providing a polymer; at least partially forming the artefact from the polymer; crosslinking the polymer through ionising irradiation; and reducing residual chemically reactive free radicals in the artefact by annealing the artefact at an elevated temperature of at least 35 0 C for an extended period of time of at least 0.5 hour in the presence of an unsaturated hydrocarbon gas.
- the polymer may be radiation crosslinked either before or after the forming of the artefact.
- the artefact is prevented from contact with oxygen in a concentration greater than 1% volume by volume.
- the method may include the further steps of: prior to the annealing step, disposing the artefact in an oxygen impervious hermetically sealed container; removing the air from the container and thus from the surface of the artefact; blanketing the artefact with the said unsaturated hydrocarbon gas by introducing the said gas into the container; and - hermetically sealing the container to contain the unsaturated hydrocarbon gas inside the sealed container.
- the step of annealing the artefact may include the step of elevating the temperature of the artefact to a temperature of between 35 0 C and 130 0 C for a time period of between 0.5 and 12 hours, while being disposed in the hermetically sealed container in the presence of the unsaturated hydrocarbon gas.
- the artefact is annealed for a period of 8 hours at a temperature of 80 0 C.
- the unsaturated hydrocarbon gas may be selected from the group consisting of alkenes (olefins) or alkynes and their gaseous derivatives such as ethylene, propylene, butylene or acetylene or mixtures thereof.
- the polymer is in the form of ultra-high molecular weight polyethylene (UHMWPE).
- UHMWPE ultra-high molecular weight polyethylene
- the container may be in the form of a hermetically sealable metal container.
- the container may be in the form of a hermetically sealable laminate polymeric pouch.
- a method of reducing residual chemically reactive free radicals in a polymeric artefact following the radiation-induced crosslinking of the polymer including the step of annealing the artefact at an elevated temperature of at least 35 °C for an extended period of time of at least 0.5 hour in the presence of an unsaturated hydrocarbon gas. Further according to the invention, during the annealing step, the artefact is prevented from contact with oxygen in a concentration greater than 1% volume by volume.
- the method may include the further steps of: prior to the annealing step, disposing the artefact in an oxygen impervious hermetically sealed container; removing the air from the container and thus from the surface of the artefact; - blanketing the artefact with the said unsaturated hydrocarbon gas by introducing the said gas into the container; and hermetically sealing the container to contain the unsaturated hydrocarbon gas inside the sealed container.
- the step of annealing the artefact may include the step of elevating the temperature of the artefact to a temperature of between 35 0 C and 130 0 C for a time period of between 0.5 and 12 hours, while being disposed in the hermetically sealed container in the presence of the unsaturated hydrocarbon gas.
- the artefact is annealed for a period of 8 hours at a temperature of 80 0 C.
- the unsaturated hydrocarbon gas may be selected from the group consisting of alkenes (olefins) or alkynes and their gaseous derivatives such as ethylene, propylene, butylene or acetylene or mixtures thereof.
- the polymer is in the form of ultra-high molecular weight polyethylene (UHMWPE).
- UHMWPE ultra-high molecular weight polyethylene
- the container may be in the form of a hermetically sealable metal container.
- the container may be in the form of a hermetically sealable laminate polymeric pouch.
- the aforesaid artefact may be selected from the group consisting of medical implants, prostheses, medical devices, gears, tools, gun parts, magazines, containers, pipes, couplings, nuts, bolts, screws, tools, drive train components, engine components, pulleys, rollers, bearings, clamps, bushes and other mechanical components.
- figure 1 is a graph illustrating the decrease in the terminal vinyl unsaturation with an increased depth into the polymer artefact.
- a method according to a preferred embodiment of the invention for forming an artefact in the form of a prosthesis, medical implant or device, and for reducing residual chemically reactive free radicals therein includes the steps of:
- UHMWPE ultra high molecular weight polyethylene
- orthopaedic implants a polymer in the form of orthopaedic implants
- an oxygen impervious hermetically sealed container such as a metal container or heat sealable laminate pouch
- an unsaturated hydrocarbon gas selected from the group of alkenes (olefins) or alkynes and their gaseous derivates such as ethylene, propylene, butylene or acetylene or mixtures thereof by introducing the said gas into the container;
- hermetically sealing the container to contain the hydrocarbon gas inside the sealed container, the arrangement being such that the atmosphere inside the container contains less than 1% oxygen if any at all; reducing residual chemically reactive free radicals in the artefact by annealing the artefact at a temperature of between 35 0 C and 130 0 C for a time period of between 0.5 and 12 hours; preferably 8 hours at a temperature of 80 0 C, while being disposed in the hermetically sealed container in the presence of the unsaturated hydrocarbon gas thus preventing the artefact from contact with oxygen in a concentration greater than 1 % volume by volume during the annealing step; and
- This annealing technique is particularly suitable for treating radiation crosslinked polymeric medical devices made from UHMWPE to protect such devices from any post-irradiation oxidative degradation.
- the present invention therefore relates to an annealing method for providing an artefact made from a radiation crosslinked feedstock of UHMWPE in which the residual concentration of chemically reactive free radicals has been reduced to a level where the risk of a post-irradiation oxidative degradation of the surface of the artefact and the associated impairment of the wear characteristics of the artefact in orthopaedic applications, especially in the load bearing surface of the artefact, is minimised.
- the presence of the unsaturated hydrocarbon gas during the annealing process acts as a crosslinking agent, thereby enhancing the radical-radical reactions and the elimination of the residual free radicals.
- This chemically active involvement of the unsaturated gas in the annealing process results in additional crosslinking of the polymer on the surface zone of the polymer during the annealing process, whilst lowering the free radical concentration in the crosslinked polymer to acceptable levels.
- the annealing conditions can thus be more moderate in terms of temperature and annealing time.
- Annealing the polymer after irradiation in nitrogen results in a melt-flow index of 0.50 g/10 min, however, carrying out the annealing in the presence of acetylene results in a lowering of the melt-flow index to 0.34 g/10 min.
- an unsaturated hydrocarbon gas during the annealing step acts as a crosslinking agent
- the nature of the additional crosslinking chemical bonds formed is chemically identical to that of the UHMWPE without any significant adverse effects in biomedical or orthopaedic applications in the case of unsaturated gasses such as ethylene, propylene, butylene and acetylene or mixtures thereof.
- the unsaturated hydrocarbon gas diffuses into the outer surface of the artefact and preferentially minimises the long-lived free radicals in the outer surface of the artefact up to a depth of at least 300 ⁇ m into the artefact surface, resulting in the enhanced surface crosslinking of the crosslinked polymer with the associated enhanced surface wear characteristics.
- This enhanced surface crosslinking of the polymer also implies that the molecular mass of the polymer will show an inhomogeneous character, being higher on the surface and decreasing into the body of the artefact. Hence, resulting in enhanced wear characteristics on the surface of the artefact, since it is known that an increase in the molecular mass of UHMWPE is associated with improved wear resistance of the polymer.
- the outer 300 ⁇ m of the annealed polymer will thus be free of residual free radicals and will have an enhanced surface crosslinking and the associated improved wear and visco-elastic characteristics.
- the total residual free radical concentration in a radiation crosslinked artefact is not necessarily indicative of the potential risk of such an artefact to undergo oxidative degradation with the associated poor wear characteristics. Rather, the free radical concentration in the outer surface of the device is important as the oxygen can react with these free radicals with the resulting oxidative surface degradation.
- annealing the radiation crosslinked artefact in the presence of an unsaturated gas will eliminate the free radicals on the surface of the artefact and thus limit any oxidative degradation, regardless of the total free radical count emanating from free radicals inside the body of the artefact that cannot react with the oxygen in the air or body fluids.
- the simulator studies were followed up by in vivo clinical trials and experiments employing a 2-D computer assisted X-ray technique developed by Martell and Berdia utilising edge detection and computer vision wear studies. Not a single radiation crosslinked polymeric prosthesis annealed in acetylene has failed as a result of polymeric material failure such as wear, cracking or osteolysis. In addition, it was found that the wear was too low to be detected by the technique used.
- the clinical in vivo trials and experiments thus confirm the favourable observations of the simulator studies - clearly demonstrating the apparent complete absence of any post- irradiation surface oxidation of the wear surfaces of acetabular cups annealed in acetylene after the radiation crosslinking thereof.
- artefacts manufactured using the method of the present invention display characteristics superior to those manufactured by using prior art methods.
- the artefacts displayed visco-elasticity and a high surface resistance to wear far superior to that of the prior art artefacts.
Landscapes
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Transplantation (AREA)
- Dermatology (AREA)
- Medicinal Chemistry (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Epidemiology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
Abstract
La présente invention a trait à un procédé pour la réduction de radicaux libres résiduels chimiquement réactifs dans des artefacts à base de polymère tels qu'une prothèse, un implant ou dispositif médical suite à une réticulation induite par le rayonnement de ceux-ci. La réticulation induite par rayonnement du polymère comprend l'étape de recuit de l'artefact dans lequel la température de l'artefact est élevée à une température de 80 °C pour une durée de 8 heures, en étant disposé dans un récipient hermétiquement scellé en présence d'un gaz d'hydrocarbures insaturé. Des artefacts fabriqués par le procédé de la présente invention présentent des caractéristiques supérieures à ceux fabriqués à l'aide de procédés de l'art antérieur. En particulier, les artefacts présentent une viscoélasticité et une résistance en surface élevée à l'usure nettement supérieure à celle des artefacts de l'art antérieur.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA2004/6063 | 2004-07-29 | ||
| ZA200406063 | 2004-07-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2006013536A1 true WO2006013536A1 (fr) | 2006-02-09 |
Family
ID=35005802
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB2005/052505 WO2006013536A1 (fr) | 2004-07-29 | 2005-07-26 | Recuit de polymères réticulés par rayonnement |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2006013536A1 (fr) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2386593A1 (fr) * | 2010-04-20 | 2011-11-16 | Robert Bosch GmbH | Procédé de mise en réseau de corps de moulage polymères avec des gaz réactifs |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997011097A1 (fr) * | 1995-09-19 | 1997-03-27 | Hoechst Celanese Corporation | Reticulation de polymeres de polypropylene par irradiation |
| WO1998015398A1 (fr) * | 1996-10-04 | 1998-04-16 | University Of Leeds Innovations Limited | Fibres d'olefines comprimees |
| WO2001088001A1 (fr) * | 1999-12-30 | 2001-11-22 | Opp Petroquímica S.A. | Procede pour preparer du polypropylene a grande resistance a la fusion et polypropylene reticule ainsi prepare |
| WO2002048259A2 (fr) * | 2000-12-12 | 2002-06-20 | Massachusetts General Hospital | Manipulation controlee et selective de polymeres |
| WO2003059200A1 (fr) * | 2002-01-04 | 2003-07-24 | Massachusetts General Hospital | Polyethylene reticule a module eleve et a concentration reduite en radicaux libres residuels elabore sous le point de fusion |
| WO2004000159A2 (fr) * | 2002-06-21 | 2003-12-31 | Massachusetts General Hospital | Reticulation de renfort ou maillage metallique |
-
2005
- 2005-07-26 WO PCT/IB2005/052505 patent/WO2006013536A1/fr active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997011097A1 (fr) * | 1995-09-19 | 1997-03-27 | Hoechst Celanese Corporation | Reticulation de polymeres de polypropylene par irradiation |
| WO1998015398A1 (fr) * | 1996-10-04 | 1998-04-16 | University Of Leeds Innovations Limited | Fibres d'olefines comprimees |
| WO2001088001A1 (fr) * | 1999-12-30 | 2001-11-22 | Opp Petroquímica S.A. | Procede pour preparer du polypropylene a grande resistance a la fusion et polypropylene reticule ainsi prepare |
| WO2002048259A2 (fr) * | 2000-12-12 | 2002-06-20 | Massachusetts General Hospital | Manipulation controlee et selective de polymeres |
| WO2003059200A1 (fr) * | 2002-01-04 | 2003-07-24 | Massachusetts General Hospital | Polyethylene reticule a module eleve et a concentration reduite en radicaux libres residuels elabore sous le point de fusion |
| WO2004000159A2 (fr) * | 2002-06-21 | 2003-12-31 | Massachusetts General Hospital | Reticulation de renfort ou maillage metallique |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2386593A1 (fr) * | 2010-04-20 | 2011-11-16 | Robert Bosch GmbH | Procédé de mise en réseau de corps de moulage polymères avec des gaz réactifs |
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