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AssigneeTakiron Co., Ltd.
InventorsYasuo Shikinami, Masaki Okuno
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A high bending strength and high density material for osteosynthesis, which comprises a biodegradable and bioabsorbable crystalline thermoplastic polymer material, and a high strength implant material, comprising a composite material in which a bioceramics powder of from 0.2 to 50 .mu.m in particle size is dispersed in the polymer material, wherein crystals of the polymer material are pressure-oriented not in a uni-axial direction but basically in parallel with a plurality of reference axes; and a production method by pressure orientation, which comprises preparing in advance a biodegradable and bioabsorbable crystalline thermoplastic polymer material or a dispersed mixture of the polymer material and a bioceramics powder and melt-molding it into a pre-molded material which is then press-charged at a cold temperature into a cavity of a closed type forming mold, thereby obtaining an oriented molding. Since the osteosynthesis and implant materials are dense and high strength oriented moldings having less anisotropy in which crystals are oriented in parallel with a plurality of reference axes, excellent ideal biomaterials can be provided which have appropriate hydrolysis property, can maintain sufficient strength during a period required for bone union and are degraded and absorbed at such a rate that they do not induce inflammatory reactions after healing of the fractured bones so that re-operation is not required.
A material for osteosynthesis having high bending strength and high density which comprises a molding comprising a biodegradable and bioabsorbable crystalline thermoplastic polymer material as a main component, wherein the molecular chains or crystals of said molding are oriented not in a uni-axial direction but in parallel with a plurality of reference axes slanted toward an axis which becomes a mechanical core of said molding occurring along the press-charging direction in the forming mold and/or continued faces of said axis.
A method for producing a material for osteosynthesis, which comprises producing an oriented molding by preparing a pre-molded material through melt molding of a biodegradable and bioabsorbable crystalline thermoplastic polymer material and then forcing the pre-molded material into a narrow space of a forming mold whose bottom part is substantially closed, while carrying out plastic deformation at a cold temperature and thereby effecting orientation by pressure deformation.
A high strength implant material as a particle- and matrix polymer-reinforced composite material, which is a composite material comprising a pressure-oriented molding in which from 10 to 60% by weight of a bioceramics powder whose particle or aggregated mass of particles has a size of from 0.2 to 50 .mu.m is dispersed substantially uniformly in matrix of a biodegradable and bioabsorbable crystalline thermoplastic polymer, wherein crystals of said matrix polymer are oriented by pressure and have a crystallinity of from 10 to 70%.
A process for producing a high strength implant material by pressure deformation orientation, which comprises preparing in advance a mixture in which a biodegradable and bioabsorbable crystalline thermoplastic polymer and a bioceramics powder are dispersed in each other substantially uniformly, subsequently producing a pre-molded material by melt molding of said mixture, and then press-charging said pre-molded material at a cold temperature into the cavity of a closed forming mold to effect plastic deformation and formation of an oriented molding.
Dependencies are inferred from the claim text.