Classifications

• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B17/00—Insoles for insertion, e.g. footbeds or inlays, for attachment to the shoe after the upper has been joined
  • A43B17/003—Insoles for insertion, e.g. footbeds or inlays, for attachment to the shoe after the upper has been joined characterised by the material
• • 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
  • A61F5/00—Orthopaedic methods or devices for non-surgical treatment of bones or joints; Nursing devices ; Anti-rape devices
  • A61F5/01—Orthopaedic devices, e.g. long-term immobilising or pressure directing devices for treating broken or deformed bones such as splints, casts or braces
  • A61F5/04—Devices for stretching or reducing fractured limbs; Devices for distractions; Splints
  • A61F5/05—Devices for stretching or reducing fractured limbs; Devices for distractions; Splints for immobilising
  • A61F5/058—Splints
• • 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
  • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
  • A61L31/12—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
  • A61L31/125—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material having a macromolecular matrix
• • 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
  • A61F5/00—Orthopaedic methods or devices for non-surgical treatment of bones or joints; Nursing devices ; Anti-rape devices
  • A61F5/01—Orthopaedic devices, e.g. long-term immobilising or pressure directing devices for treating broken or deformed bones such as splints, casts or braces
  • A61F5/14—Special medical insertions for shoes for flat-feet, club-feet or the like
• • 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
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/07—Stiffening bandages
  • A61L15/12—Stiffening bandages containing macromolecular materials
• • 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
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/07—Stiffening bandages
  • A61L15/12—Stiffening bandages containing macromolecular materials
  • A61L15/125—Mixtures of macromolecular compounds
• • 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
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/07—Stiffening bandages
  • A61L15/14—Use of materials characterised by their function or physical properties
• • 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
• • 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
  • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
  • A61L27/58—Materials at least partially resorbable by the body
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L97/00—Compositions of lignin-containing materials
  • C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B71/00—Games or sports accessories not covered in groups A63B1/00 - A63B69/00
  • A63B71/08—Body-protectors for players or sportsmen, i.e. body-protecting accessories affording protection of body parts against blows or collisions
  • A63B71/12—Body-protectors for players or sportsmen, i.e. body-protecting accessories affording protection of body parts against blows or collisions for the body or the legs, e.g. for the shoulders
  • A63B71/1225—Body-protectors for players or sportsmen, i.e. body-protecting accessories affording protection of body parts against blows or collisions for the body or the legs, e.g. for the shoulders for the legs, e.g. thighs, knees, ankles, feet
  • A63B2071/1258—Body-protectors for players or sportsmen, i.e. body-protecting accessories affording protection of body parts against blows or collisions for the body or the legs, e.g. for the shoulders for the legs, e.g. thighs, knees, ankles, feet for the shin, e.g. shin guards
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B2209/00—Characteristics of used materials
  • A63B2209/18—Characteristics of used materials biodegradable
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/06—Biodegradable
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/02—Applications for biomedical use
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component

Definitions

• the present invention relates, in general to the field of manufacturing wood-plastic composite (WPC).
• WPC wood-plastic composite
• present invention relates to the production of composite materials comprising wood particles and biodegradable thermoplastic polymer. More particularly, the present invention relates to a method of manufacturing novel wood-plastic composites useful as splints or casts in immobilization of a fractured body extremities.
• thermoplastic polymers in particular polycaprolactone and finely divided wood powder or fibres and thermoplastic polymers.
• these structures are of the “mesh type” consisting of cellulosic fibers with an average particle size less than 0.6 mm.
• a mesh type casting material is presented in Published International Patent Application WO 94/03211.
• the material is manufactured by using a powder deposition process. The process includes mixing, with a dispensing hopper, depositing the material to the non-woven fabric followed by a pressing procedure and a heat treatment procedure at a double-band press.
• Powder deposition is however suitable only for manufacturing homogenized composites with fine particles. Moreover, the double-bend press cannot gently homogenize the wood particles with rather large dimensions to an evenly distributed mixture with polymer matrix.
• the novel technology is based on the concept of mixing a thermoplastic polymer selected from the group of biodegradable polymers with at least one reinforcing material selected from woody materials in the form of platy and granular wood particles in particular under conditions of melt mixing.
• the mixing is carried out in an apparatus for melt processing of polymers, e.g. an extruder or an equivalent device capable of producing a compounded mixture of thermoplastic and additives, at an elevated temperature and optionally at an increased pressure.
• the elevated temperature corresponds to or is higher than the melt temperature of the polymer.
• the present invention is characterized by what is stated in the characterizing part of claim 1 .
• the method will produce light-weight dimensionally stable wood-thermoplastic composite materials composed of wood chips and a thermoplastic polycaprolactone. During the gentle manufacturing process fragile wood chips maintain their 3-D structural properties in polymer matrix resulting light, mechanically strong wood-plastic composite.
• the material of the present invention can generally be manufactured by mixing a first component, i.e. a suitable polymer material, for example in the form of pellets, with the second component, i.e. wood particles or granules, by melt mixing.
• the mixing can be carried out in any conventional apparatus designated for melt mixing or melt processing.
• One example is a heatable vessel having a mechanical stirrer.
• the composite can be formed by using an extruder, kneader or any device suitable for mixing thermoplastic polymers, in particular for mixing of polymers in melt phase.
• the mixture of the first and second components prior to melting is a homogeneous mixture of the two components.
• two hoppers each containing one of the components of the material, can deposited the desired amount of each component in to a mixing chamber of the apparatus. Then, by way of the mixing means in the mixing apparatus, there is formed a homogeneous mixture of the first and second components prior to the formation of the composite material.
• One advantage to the material being formed by such a homogeneous mixture of the components is that the forces necessary to form a substantially homogeneous material are reduced. Therefore, little or no compression force is necessary to facilitate mixing of the components in a material formation step. The importance of this factor is that, by way of the homogeneous mixture, larger particles of each component can be used which would otherwise have been destroyed when subjected to high compression forces.
• the material can be applied for use after it has been recovered from the mixing device and formed into the desired shape, for example into a sheet or plate or roll or any similar planar, folded, bent or tubular structure.
• the material can even be formed directly on the patient.
• the material mixed with an extruder can be shaped with an appropriate nozzle to the shape of, e.g. a rectangular sheet or plate which can be used directly after cutting, e.g. as a wrist splint.
• a sheet or plate whose purpose is to be later formed in to a desired shape or size is referred to herein as a blank.
• a desired specific profile or shape for the splints can be manufactured with the extruder manufactured sheet or plate by optical, chemical or mechanical cutting, e.g. laser cutting, water jet cutting, eccentric pressing, or with any tool capable for producing regular shape profiles, i.e. stamping.
• the present material can also be processed with compression moulding, injection moulding, die-casting, and pressure die-casting. Ideally these specific profiles and shapes are in linear, two-dimensional form so as to be easily and compactly storable. To maintain the simplicity and cost effectiveness in the manufacturing process of the novel composite material of the present invention preferably the whole manufacturing process of the end-product is continuous.
• the present method of producing a composite useful as an orthopedic material comprises the steps of;
• the melt-mixing is carried out at a temperature sufficient for melting the thermoplastic polymer.
• the mixing is generally carried out at a temperature of about 50 to 190° C., preferably about 90 to 150° C., in particular about 100 to 130° C., in order to achieve conditions of melt-mixing in the apparatus.
• the temperature can also be in the range of about 50 to 150° C., in particularly about 100 to 140° C.
• the molten polymer mass containing a mixture of biopolymer and reinforcing platy particles can be shaped manually or, according to a preferred embodiment by moulding in a mould.
• the molten polymer mass can be subjected to tensile forces to achieve a desired orientation of the polymer and, in particular, the reinforcing particles.
• the manufacturing process comprises several preferred embodiments.
• a preferred embodiment of the manufacturing process of a composite material comprises the steps of compounding: virgin materials with an extruder and production of uniform homogeneous plate-like composite.
• One particular embodiment consist of compounding wood chips and thermoplastic polymer with single screw extruder and profile manufacturing of therein produced composite by using calendaring techniques.
• This manufacturing method is applicable for production of composites consisting of any thermoplastic polymer having a melting point below 100° C. and wood particles having volume between 1-50 mm 3 .
• the manufacturing process is initiated by mixing wood chips and plastic granules to uniform blend before pouring to feed hopper of the extruder.
• the mixing process can be carried out also by feeding of the virgin materials to the extruder directly by using separate feeding hoppers.
• the profile of screw has to have dimensions that allow relatively lame wood chips (up to about 30 to 50 mm in one dimension) to move along the screw without crushing them. Simultaneously, appropriate dispersion between wood and polymer has to be achieved.
• the screw-like channel width and flight depth are selected such that formation of local pressure increases can be avoided.
• the temperature of cylinder and the screw rotation speed are selected to avoid decomposition of wood chip structure by high pressure during extrusion.
• the appropriate barrel temperature is generally in the range of 80 to 190° C., preferably 100 to 150° C., e.g. 116-135° C., from hopper to die.
• the screw rotation speed is typically about 10 to 100 rpm, for example 25 to 50 rpm.
• the extruder compounded composite material can be further worked upon to obtain homogeneous plates or sheets with a thickness of about 1 to 5 mm, e.g. 3.5 mm, with preselected width and length by using calendering techniques.
• composite material can be gently folded between calendering cylinders in a plurality of phases, each consisting of a number of cycles. For example 2 phases with at least 10 cycles each are preferred.
• the melt mixing is carried out in an extruder and the calendering process comprises several cycles of folding, cooling and reheating steps.
• the temperature of calender cylinders can be kept constant, for example at a temperature above the melting point of the thermoplastic material, to keep the composite moldable during calendering process.
• Plates can be finished by sanding the edges with band sander.
• the calender cylinders were kept at 100° C. Smooth surface to the final product were achieved by calendering the plate one time through at 100° C.
• Alternative manufacturing process for the composite plates is press method after the mixing process carried out with extruder.
• Pneumatic, mechanical and/or hydraulic presses are suitable for the press method of the composite. During pressing the heated plates of the press are kept at temperature
• the density of composite manufactured with combination of extruder and calendaring or extruder and press vary between 600-1050, e.g. 600-850 kg/m 3 depending on the weight percent of wood in material.
• the complete manufacturing process of the end-product is preferably continuous.
• Low viscosities of the polymers at elevated temperatures complicate the manufacturing process of the multi-component composites. For example pressing of hook-and-loop fasteners to the surface of composite at elevated temperatures tearing and creeping of the composite material can be observed.
• the present manufacturing method is therefore particularly well suited for the processing of highly viscous thermoplastics, such as PCL having an MFI value of 3, as a polymer component. After mixing procedure with extruder the formed mixture of wood and a PCL of the indicated MFI value can be directly used in calandering process. The creep phenomenon of the molten composite during pressing fasteners onto it can be avoided when the wood weight percentage in the composite is at least 20.
• the adhesion of the composite can be improved by coating the surface of the composite with additional layer of virgin PCL or with any similarly behaving material.
• the coating process can be performed practically either by extrusion coating or extrusion laminating in a continuous process.
• extrusion coating a molten layer of extrudate is laid onto a composite.
• the temperature of the extruded molten polymer is kept below 200° C. to avoid tarnishing of the wood component and at the same time above 100° C. to guarantee reasonable flow of the polymer on the substrate.
• the polymer wets the entire surface evenly and smooth over uneven surface which is important contributor to adhesion.
• Composite consisting of three layers of compounds can be performed by extrusion laminating. In the process two substrates (PCL) enters the nip formed by two rolls. The middle extrudate (composite) also enters the nip by traveling over each roll. The composite is therefore the center part of the resulting sandwich material.
• the manufacturing of the multilayer composite consisting of composites layers having different weight percentage of wood can be performed by using calandering techniques. Two or more molten extrudates are combined to sandwich type of structures and pressed together in calender. By using similar calandering technique also padding and fasteners can be pressed to the molten composite extrudate consisting of one or multi layers.
• the composite retains its shape as it cools down. It is substantially rigid but flexible so as to be supportive and comfortable. Rigidity is generally achieved, when a sample heated to the above indicated softening temperature is cooled to below 50° C., in particular to less than 45° C., preferably less than 40° C. Typically, the composite is rigid at ambient temperature; a suitable temperature of use is about ⁇ 40 to +50° C., in particular ⁇ 30 to +40° C.
• the composite material sheet or plate can have a thickness of, generally about 0.2 to 50 mm, in particular about 1.5 to 30 mm, for example 1.5 to 20 mm. A typical thickness is about 2 to 6 mm.
• the length and the width of the sheet or plate can vary in the range of about 1 to 150 cm (length) and to 50 cm (width), a typical length being about 10 to 60 cm and a typical width being about 5 to 20 cm.
• a particular embodiment comprises producing a continuous product, collecting the product and rolling it or folding it. Such a product is then provided in the form of ribbons or tape which can be collected on a receiving roller.
• a linear product e,g. a sheet or a plate
• That laminar product can be further processed.
• it can be perforated.
• Another alternative is to use the linear product for making a laminate comprising at least two layers, each preferably being comprised of such linear products.
• the laminate can be perforated, also,
• One specific embodiment comprises the steps of providing on a laminate at least one surface layer having a reduced content of woody material.
• the layer can be formed by neat polymer or by a polymer merely having a reduced content of the woody material. Such a surface layer will provide improve adhesive properties for the product.
• a particularly interesting embodiment comprises producing an essentially linear product, and mechanically modifying, e.g. by corrugation, the linear product so as to increase its stiffness.
• the product produced by the present invention can also comprise further fillers or enforcing components.
• one embodiment comprises mixing the thermoplastic polymer with a first woody material and at least one second woody material, said second woody material being different from the first woody material.
• a still further embodiment of producing a biodegradable linear composite material capable of being used to form an exo-skeletal device through thermal molding comprises the steps of;
• obtaining a desired woody particle mixture comprises the step of taking a woody particle feed having a plurality of sized woody particles and sorting the feed to obtain the desired woody particle mixture.
• the step of sorting the woody particle feed may comprise sifting the feed through one or more meshes.
• more than 70% of the second component is formed by the woody particle mixture.
• the first and second components may have pellets and particles of similar size.
• the desired shape is a substantially rectangular blank formed from an extruder.
• the desired shape may, however, be other than a rectangular blank and can be formed by optically, chemically or mechanically cutting or stamping the desired form from the composite material.
• the proportions between the components of the material can vary in a broad range.
• 5 to 99 wt-%, for example 40 to 99 wt-%, of the material is formed by the thermoplastic polymer component and 1 to 95 wt-%, for example 1 to 60 wt-%, by the woody material.
• the weight ratio of polymer-to-wood can easily be modified. and the weight percent of wood, based on the total weight/volume of the composition, may vary between 1 and 70%, preferably however in the range of 10 to 60 weight percent, or 20 to 60 weight percent, and 15 to 50%, or 25 to 50%, by volume.
• the second component comprises a woody material having a smallest diameter of greater than 0.1 mm. As will be discussed below, there can also be other wood particles present in the second component and the woody material can be granular or platy.
• the size and the shape of the wood particles may be regular or irregular.
• the particles have an average size (of the smallest dimension) in excess of 0.1 mm, advantageously in excess of 0.5 mm, for example in excess of 0.6 mm, suitably about 1 to 40 mm, in particular about 1.2 to 20 mm, preferably about L5 to 10 mm, for example about 1.5 to 7 mm
• the length of the particles (longest dimension of the particles) can vary from a value of greater than 1 mm to value of about 1.8 to 200 mm, for example 3 to 21 mm.
• the woody particles can be granular, platy or a mixture of both.
• Woody particles considered to be platy means that they have generally a plate-shaped character, although particles of other forms are often included in the material.
• the ratio of the thickness of the plate to the smaller of the width or length of the plate's edges is generally 1:1 to 1:500, in particular about 1:2 to 1:50.
• the platy particles of the present invention generally comprise wood particles having at least two dimensions greater than 1 mm and one greater than 0.1 mm, the average volume of the wood particles being generally at least 1 min 3 ′ more specifically at least 1 mm 3 .
• Derived from platy wood particles designates that the wood particles may have undergone some modification during the processing of the composition. For example, if blending of the first and second components is carried out with a mechanical melt processor, some of the original platy wood particles may be deformed to an extent.
• the wood species can be freely selected from deciduous and coniferous wood species alike: beech, birch, alder, aspen, poplar, oak, cedar, Eucalyptus, mixed tropical hardwood, pine, spruce and larch tree for example.
• woody material of the composite can also be any manufactured wood product.
• the particles can be derived from wood raw-material typically by cutting or chipping of the raw-material. Wood chips of deciduous or coniferous wood species are preferred.
• a particularly interesting raw-material comprises wood chips of any of the above mentioned wood species having a screened size of greater than 0.6 mm and up to about 3 mm, in particular about 1 to 2.5 mm on an average.
• a composite useful as an orthopedic material comprises a first component formed by a polymer and a second component formed by a reinforcing material, wherein the first component comprises a thermoplastic polymer selected from the group of biodegradable polymers and mixtures thereof, and the second component comprises reinforcing fibres.
• Such fibers can be selected from the group for example of cellulose fibers, such as flax or seed fibers of cotton, wood skin, leaf or bark fibers of jute, hemp, soybean, banana or coconut, stalk fibers (straws) of hey, rice, barley and other crops including bamboo and grass.
• the wood filler may consist of or consist essentially of fibres of the indicated kind.
• the polymer component can be any of the below listed polymers, caprolactone homo- or copolymers having a molecular weight of about 60,000 g/mol up to 250,000 g/mol being particularly preferred.
• the polymer component is a caprolactone homopolymer or a blends of homo- or copolymers of epsilon-caprolactone having a molecular weight of above 80,000 g/mol.
• polycaprolactone having a molecular weight of between 100,000 g/mol and 200,000 g/mol as been found to be advantageous both in terms of resultant properties and cost.
• the woody particles Before the woody particles are mixed with the thermoplastic polymer they can be surface treated, e.g. sized, with agents which modify their properties of hydrophobicity/-hydrophobicity and surface tension. Such agents may introduce functional groups on the surface of the granules to provide for covalent bonding to the matrix. Even increased hydrogen bonding or bonding due to van der Waals forces is of interest.
• the woody particles can also be surface treated with polymer e.g. PCL having low viscosity and molar mass values to increase holding powers between wood and PCL having high viscosity value.
• the wood material can be also coated or treated with anti-rot compound e.g. vegetable oil to improve its properties against aging and impurities.
• anti-rot compound e.g. vegetable oil
• the wood material can be dehydrated to make it lighter before mixing it with polymer.
• the mechanical and chemical properties of wood material can be improved with heat treatment, which is known to decrease e.g. swelling and shrinkage.
• the first component (the polymer) forms the matrix of the composite, whereas the microstructure of the second component in the composition in discontinuous.
• the particles of the second component can have random orientation or they can be arranged in a desired orientation.
• the desired orientation may be a predetermined orientation.
• composition may contain particulate or powdered material, such as sawdust, typically having particles with a size of less than 0.5 mm*0.5 mm*0.5 mm.
• Particulate or powdered material is characterized typically as material of a size in which the naked eye can no longer distinguish unique sides of the particle. More specifically, powder particles are of such a size that their dimensions cannot be measured with traditional, Vernier, calipers.
• non-powder particles are of such a size that they can be measured with traditional calipers.
• platy particles are easily recognizable as one dimension is recognizable by the naked eye as being larger than another.
• Granular particles while having substantially equal dimensions, are of such dimension that their unique sides can be determined by the naked eye and oriented.
• particulate or powdered materials are of such a small or fine size that they cannot be easily oriented with respect to their neighbours.
• Granular and platy particles are of such as size that their sides are recognizable and orientable.
• the present material contains a significant portion of wood granules having a particle size greater than the micrometer range, for example a size of about 0.75 mm to 50 mm.
• a size of about 0.75 mm to 50 mm When the material is shaped into a sheet, (at least most of) the wood granules become oriented in two dimensions within forming of the thermoplastic material into sheets.
• the reinforced material typically exhibits properties selected from one or several of the following:
• the desired composition of the second component can be achieved by sifting woody particles through one or more meshes having one or more varying qualities.
• the desired composition can also be accomplished by other well known techniques in the art for sorting and separating particles in to desired categories.
• the desired composition may be the resultant composition of one sifting or separating process.
• the desired composition may also be a mixture of resultant compositions from several sifting or separation processes.
• the weight ratio of fibrous material (optionally including said powdered material) to the platy material (dry weight) is about 1:100 to 100:1, preferably about 5:100 to 50:50.
• the woody material derived from the platy wood particles forms at least 10%, preferably about 20 to 100%, in particular about 30 to 100%, of the total weight of the second component.
• the powdered material may form up to 30%, typically about 1 to 20%, of the total weight of the second component.
• inorganic particulates or powdered materials such as mica, silica, silica gel, calcium carbonate and other calcium salts such as tricalcium orthophosphate, carbon, clays and kaolin may be present or added.
• the present method will produce a composition that can be used as a composite material.
• Such materials are exemplified by finger splints, wrist casts and ankle casts.
• the platy particles form about 30 to 70%, preferably in excess of 40 up to about 60%, of the total weight of the composition, for finger splints and for ankle casts about 20 to 60%, preferably about 30 to 50% of the total weight of the composition.
• the composite material of the present invention is manufactured in to either a blank or in to a desired, specific shape or form.
• the blanks and forms are linear, two dimensional and easily stackable.
• the blanks can be either substantially larger than the intended size to be applied to the animal or human being, herein referred to as the patient, or of substantially similar size.
• the blank can be cut with normal scissors or other conventional cutting means before application.
• a large blank is preferable in the sense that one blank may be cut in to several splints at various times according to the size required by each. Therefore, it is not necessary to store many different shapes and sizes of the material, which take up room and may be rarely used.
• multiple splints may be cut from one blank in such a way as to maximize the material used and not produce a large amount of waste product.
• the material is then heated to the desired operating temperature by a heating means.
• a heating means Numerous heating means are known in the art, but it is preferable to uniformly heat the material to a specific desired temperature. If the temperature is too high then there is risk of discomfort or harm to the patient's skin. If the temperature is not high enough then the material will not be able to properly conform to the patient's body.
• Table 1 is a table chart showing the densities of the test specimens manufactured by calandering at different temperatures
• Table 2 is a table chart showing the flexural strengths of the test specimens manufactured by calandering at different temperatures
• Table 3 is a table chart showing the tensile strengths of the test specimens manufactured by calandering at different temperatures.
• Table 4 is a table chart showing the densities of the test specimens with different wood weight percentage manufactured by extrusion and calandering at different temperatures.
• the polycaprolactone polymer used was a commercially available PCL homopolymer supplied under the tradename CAPA 6800 by Perstorp Ltd., Sweden).
• the polycaprolactone has a melt flow rate of about 3 g/10 min (measured at 150° C. and with a weight of 2.16 kg).
• the wood material if not otherwise indicated, was conventional spruce chips produced at a Finnish saw mill. In some of the examples wood particles of other wood species were used.
• the spruce chips were dried for 4 hours in 120° C. and polymer granules were used as received. Preliminary mixing of virgin materials was carried out in a sealed plastic vessel. The mixture (200 g wood chips/300 PCL granules) was poured to the feed hopper connected to the Brabender single-screw extruder. The rotational speed of the extruder was set to 50 rpm and the temperatures of all four zones were fixed at 130° C. After compounding process with the extruder, the formed composite material was heated in the oven to 125° C. to ensure its easy mouldability during calendering process.
• the calendering of composite mixture to a homogeneous plate was carried out in three phases which all included several cycles, folding, cooling and reheating steps.
• the temperature of calender cylinder was fixed at 100° C.
• After calendering process the plate-like composite was cut with band-saw to size of 10 cm by 40 cm followed by one cycle calendering at 100° C. to achieve smooth surface to casting material.

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