Device comprising a composite material

Abstract

The present invention relates to a device, which comprises a compression-molded body part, and the compression-molded body part comprises at least one composite material layer. The composite material comprises reinforcing fibers and polyaryletherketone. At least one composite material layer has a first region and a second region, wherein the content of polyaryletherketone in the first region is higher than that in the second region.

Description

Background Art

[0001] The present invention relates to a device comprising a compression molded body part, the compression molded body part comprising a composite material layer. The present invention also relates to a method of manufacturing such a device.

[0002] Composite materials comprising polymers and reinforcing fibers are known. Examples of such composite materials include carbon fibers and polyaryletherketone (PAEK). For example, the composite material comprises carbon fibers and polyetheretherketone (PEEK).

[0003] Such composite materials can be used in a variety of applications, including for example the manufacture of medical devices. For example, such composite materials can be used to manufacture implantable devices such as orthopedic implants. Brief Description of the Drawings

[0004] Embodiments of the present invention are described by way of example with reference to the following drawings, in which:

[0005] Figure 1 is a schematic view of a ply arrangement that can be used to manufacture a device by compression molding;

[0006] Figure 2 is a schematic view of a fracture plate template for forming a fracture plate tested in a reference example;

[0007] Figure 3 is a schematic view of a fracture plate tested in a reference example;

[0008] Figure 4 is a schematic view of a fracture plate template for forming a fracture plate tested in Example 1. Detailed Description

[0009] According to one aspect of the present invention, there is provided a device comprising a compression molded body part, the compression molded body part comprising at least one composite material layer, the at least one composite material layer comprising reinforcing fibers and polyaryletherketone; wherein the at least one composite material layer has a first region and a second region, wherein the polyaryletherketone content in the first region is higher than the polyaryletherketone content in the second region.

[0010] The reinforcing fibers in the second region can form continuous filaments. For example, the length of the filaments can be substantially uninterrupted throughout the second region of at least one layer. These continuous filaments can extend in substantially the same direction. Preferably, the continuous filaments can be interrupted or discontinuous in the first region to provide a first region with an increased polyaryletherketone content. Thus, the first region can have a low reinforcing fiber content or can be substantially free of reinforcing fibers.

[0011] Preferably, the compression-molded body portion includes a plurality of layers. Preferably, the compression-molded body portion may include a composite material layer that includes reinforcing fibers forming continuous filaments. The continuous filaments may extend in a substantially uninterrupted manner along a plane of the layer (e.g., length or width). The continuous filaments may extend in substantially the same direction in each layer. In some examples, the continuous filaments may extend along at least 80%, preferably at least 90%, more preferably at least 95%, even more preferably at least 98% of the plane of the layer (e.g., length or width). In some examples, the continuous filaments in one layer are positioned at an angle to the continuous filaments in an adjacent layer.

[0012] In one example, the compression-molded body portion may include a core portion that includes at least one layer, such as a composite material layer that includes reinforcing fibers forming continuous filaments.

[0013] The continuous filaments may be interrupted in the outer layer of the compression-molded body to provide a first region having a higher polyaryletherketone content to the outer layer. The continuous filaments in the outer layer may be positioned substantially at a right angle to the continuous filaments of the underlying layer. The outer layer may present, for example, an outer surface through which, for example, a fixing device (e.g., a screw) may be driven through the body portion of the device.

[0014] According to another aspect, a method of manufacturing a device is provided. The method includes removing a portion of a first layer of a composite material that includes reinforcing fibers and polyaryletherketone to form a first cutout region in the first layer; bringing a second layer of the composite material into contact with the first composite material layer such that at least a portion of the second layer overlaps at least a portion of the first cutout region; and compression-molding the layers of the composite material together such that some of the polyaryletherketone in the second layer of the composite material flows into the first cutout region.

[0015] The device of the present disclosure includes a compression-molded body portion that includes at least one layer, such as a plurality of composite material layers. The composite material includes polyaryletherketone and reinforcing fibers (e.g., carbon fibers). At least one layer of the molded body portion has a first region that has a relatively low ratio of reinforcing fibers to polyaryletherketone. The first region may be formed, for example, during the compression molding process by cutting out a portion of the composite material in the layer to form a cutout region. By cutting out a portion of the composite material in this way, the continuity of the reinforcing fibers may be interrupted. During compression molding, polyaryletherketone from adjacent layers flows into the cutout region, thereby forming a region having an increased polyaryletherketone content.

[0016] The mechanical properties of the first region of the layer can be different from those of the remainder of the layer (e.g., the second region). For example, a higher polyaryletherketone content in the first region can provide enhanced flexibility and / or ductility to the first region. This can be used to reduce the risk of crack propagation and / or delamination, for example, when the molded body part is subjected to insertion torque. Such insertion torque can be applied when a screw is driven into a hole (e.g., a threaded hole (e.g., a screw hole) or a non-threaded hole) in the molded body part. Otherwise, such insertion torque can cause, for example, delamination (e.g., delamination of the outer layer of the molded body part) and / or cracking adjacent to the hole. Additionally, any interruption or discontinuity of the continuous fibers can disrupt the stress traveling along the fibers and between adjacent layers. This can reduce the risk of delamination and / or crack propagation.

[0017] In some cases, the molded body part can include holes. There can be multiple holes. The holes can be configured to receive fastening devices, for example, to secure an object to the molded body, and vice versa. The hole can be a threaded hole, such as a screw hole. The molded body part includes at least two holes (e.g., screw holes).

[0018] In some cases, the first region of the composite layer can be adjacent to a hole. By positioning the first region adjacent to the hole, the risk of crack formation, crack propagation, and / or delamination can be reduced due to the increased flexibility provided by the first region. Preferably, the first region can define at least part of the hole wall. The first region can extend from the hole to the outer edge of the molded body part. Such a region can reduce the risk of crack formation and / or crack propagation from the hole to the outer edge of the molded body part. In some cases, the molded body part includes at least two holes. The first region can extend between the two holes. This can reduce the risk of crack formation and crack propagation between the holes, for example, when the molded body part is subjected to insertion torque.

[0019] In some cases, the composite layer including the first region and the second region forms the outer layer of the molded body part. The outer layer can form the upper surface and / or the lower surface of the molded body part. As described above, the first region has an increased polyaryletherketone content. This can reduce the risk of delamination of the outer layer of the molded body part, for example. In some cases, multiple outer layers of the molded body each include a first region having an increased polyaryletherketone content. The first regions of each of these outer layers can overlap to provide a region of increased polyaryletherketone content, for example, the region can be multiple layer thicknesses.

[0020] The first region can be substantially free of reinforcing fibers. In the case where the first region is substantially free of reinforcing fibers, the volume ratio of the reinforcing fibers to the polyaryletherketone can be less than 1.3:1, preferably less than 0.5:1, more preferably less than 0.2:1 or less than 0.1:1.

[0021] The volume ratio of reinforcing fibers to polyaryletherketone in the second region (or the remainder of the layer) can be from 0.5 to 2:1. Preferably, the volume ratio of reinforcing fibers to polyaryletherketone in the second region (or the remainder of the layer) can be from 0.8 to 1.5:1, more preferably from 0.9 to 1.2:1.

[0022] The compression-molded body portion may also include at least one layer formed of a composite material, the at least one layer as a whole having a substantially the same volume ratio of reinforcement to polyaryletherketone. Such a layer preferably does not have a first region with an increased polyaryletherketone content. In some cases, the compression-molded body portion may include such a layer as a core layer or an intermediate layer of the compression-molded body portion. The compression-molded body portion may include a plurality of such layers as core layers or intermediate layers of the compression-molded body portion. In some cases, the volume ratio of reinforcement to polyaryletherketone in such a layer is the same as the volume ratio of reinforcement to polyaryletherketone in the second region. The volume ratio of reinforcing fibers to polyaryletherketone in such a layer can be from 0.5 to 2:1. Preferably, the volume ratio of reinforcing fibers to polyaryletherketone can be from 0.8 to 1.5:1, more preferably from 0.9 to 1.2:1.

[0023] Preferably, the reinforcing fibers are carbon fibers.

[0024] Preferably, the polyaryletherketone is polyetheretherketone (PEEK).

[0025] The composite material can be provided in the form of a tape. The layer (also referred to as a "lamina") can be formed from joined portions of the tape. The composite material can take the form of a net or other precursor that can be used to form the compression-molded body portion of a desired shape and / or configuration.

[0026] The device can be a medical device, such as an implantable device. Examples of implantable devices include orthopedic implants, such as fracture plates, trauma plates, spinal implants, and other load-bearing implantable devices.

[0027] The composite material can additionally include additives in the matrix. Examples of additives include bioactive agents (such as hydroxyapatite) or imaging contrast agents (such as barium sulfate). In some examples, the composite material can include an imaging contrast agent. The imaging contrast agent can be present in all layers or selected layers of the composite material. The contrast agent can be a material that can be detected by X-rays. For example, the contrast agent can be barium sulfate.

[0028] Polyaryletherketone

[0029] Any suitable polyaryletherketone can be used in the composite material of the present invention.

[0030] Suitable polyaryletherketones can have a repeating unit of the following formula (I):

[0031]

[0032] wherein t1 and w1 independently represent 0 or 1, and v1 represents 0, 1, or 2.

[0033] The polyaryletherketone suitably comprises at least 90 mol%, 95 mol%, or 99 mol% of the repeating units of formula I.

[0034] The polyaryletherketone may comprise the repeating units of formula I or consist essentially of the repeating units of formula I. Preferred polymeric materials comprise the repeating units (or consist essentially of the repeating units), wherein t1 = 1, v1 = 0 and w1 = 0; t1 = 0, v1 = 0 and w1 = 0; t1 = 0, w1 = 1, v1 = 2; or t1 = 0, v1 = 1 and w1 = 0. More preferably, the polyaryletherketone comprises repeating unit I (e.g., consists essentially of repeating unit I), wherein t1 = 1, v1 = 0 and w1 = 0; or t1 = 0, v1 = 0 and w1 = 0. Most preferably, the polyaryletherketone comprises the repeating units (especially consists essentially of the repeating units), wherein t1 = 1, v1 = 0 and w1 = 0.

[0035] In a preferred embodiment, the polyaryletherketone is selected from polyetheretherketone, polyetherketone, polyetherketoneetherketoneketone, and polyetherketoneketone.

[0036] In a more preferred embodiment, the polyaryletherketone is polyetheretherketone or PEEK.

[0037] In some examples, the polyaryletherketone (e.g., PEEK) may have a notched Izod impact strength of at least 4 KJ / m² -2 , preferably at least 5 KJ / m² -2 , more preferably at least 6 KJ / m² -2 (for specimens 80 mm × 10 mm × 4 mm (Type A) with a 0.25 mm notch, tested at 23 °C according to ISO 180). The notched Izod impact strength measured as described above may be less than 10 KJ / m² -2 , suitably less than 8 KJ / m² -2 . The notched Izod impact strength measured as described above may be at least 3 KJ / m² -2 , suitably at least 4 KJ / m² -2 , preferably at least 5 KJ / m² -2 . The notched Izod impact strength may be less than 50 KJ / m² -2 , suitably less than 30 KJ / m² -2 .

[0038] The polyaryletherketone (e.g., PEEK) suitably has a melt viscosity (MV) of at least 0.06 kN·s / m -2 , preferably having a melt viscosity of at least 0.09 kN·s / m -2, more preferably at least 0.12 kNsm -2 of the MV. The polyaryletherketone (e.g., PEEK) can have a MV of less than 1.00 kNsm -2 , preferably less than 0.5 kNsm -2 of the MV.

[0039] The polyaryletherketone (e.g., PEEK) can have a MV in the range of 0.09 kNsm -2 to 0.5 kNsm -2 , preferably in the range of 0.1 kNsm -2 to 0.3 kNsm -2 , preferably having a MV in the range of 0.1 kNsm -2 to 0.2 kNsm -2 . A MV of 0.15 kNsm -2 has been found to be particularly advantageous. The MV is suitably measured using a capillary rheometer (using a tungsten carbide die, 0.5 mm × 3.175 mm, shear rate of 1000 s -1 , operating at 400 °C).

[0040] In a preferred embodiment, the polyaryletherketone (e.g., PEEK) has a melt viscosity (MV) of 0.09 kNsm -2 to 0.5 kNsm -2 .

[0041] The polyaryletherketone (e.g., PEEK) can be amorphous or semi-crystalline. The polyaryletherketone is preferably crystalline. The polyaryletherketone is preferably semi-crystalline. For example, as described by Blundell and Osborn (Polymer 24, 953, 1983), the level and degree of crystallinity in the polymer are preferably measured by wide-angle X-ray diffraction (also known as wide-angle X-ray scattering or WAXS). Alternatively, the crystallinity can be evaluated by differential scanning calorimetry (DSC).

[0042] The crystallinity level of the polyaryletherketone (e.g., PEEK) can be at least 1%, suitably at least 3%, preferably at least 5% and more preferably at least 10%. In a particularly preferred embodiment, the crystallinity can be greater than 25%. The crystallinity can be less than 50% or less than 40%.

[0043] The main peak of the melting endotherm (Tm) of the polyaryletherketone (if crystalline) can be at least 300 °C. In the case of using, for example, PEEK, the main peak of the melting endotherm (Tm) can be at least 300 °C.

[0044] The composite material may comprise any suitable amount of polyaryletherketone (e.g., PEEK). For example, the composite material may comprise at least 20% by volume, preferably at least 25% by volume, more preferably at least 30% by volume, still more preferably at least 35% by volume, even more preferably at least 37% by volume, and most preferably at least 39% by volume of polyaryletherketone (e.g., PEEK). The composite material comprises at most 48% by volume of polyaryletherketone (e.g., PEEK). In some embodiments, the composite material may comprise at most 45% by volume, at most 43% by volume of polyaryletherketone (e.g., PEEK).

[0045] In some embodiments, the composite material may comprise 20% to 48% by volume, preferably 30% to 48% by volume, more preferably 35% to 48% by volume, still more preferably 37% to 48% or 38% to 48% by volume of polyaryletherketone (e.g., PEEK). More preferably, the composite material may comprise 39% to 48% by volume, even more preferably 39% to 45% by volume of polyaryletherketone (e.g., PEEK). In some embodiments, the composite material may comprise 39% to 43% by volume of polyaryletherketone (e.g., PEEK).

[0046] The volume ratio of the reinforcing fiber to polyaryletherketone (e.g., PEEK) is from 1.1:1 to 1.5:1, such as from 1.2:1 to 1.4:1.

[0047] Reinforcing fiber

[0048] Any suitable reinforcing fiber may be used. The fibers used may be selected from inorganic fiber materials or organic fiber materials. The fibers may have a melting temperature or decomposition temperature greater than 200 °C, such as greater than 250 °C or greater than 300 °C. In some embodiments, the fibers may have a melting temperature greater than 350 °C or 500 °C. Examples of suitable fibers include aramid fibers, carbon fibers, glass fibers, carbon fibers, silica fibers, zirconia fibers, silicon nitride fibers, boron fibers, and potassium titanate fibers. The most preferred fiber is carbon fiber.

[0049] The reinforcing fiber (e.g., carbon fiber) may have a tensile strength greater than 4200 MPa, preferably greater than 4500 MPa, more preferably greater than 4800 MPa.

[0050] The reinforcing fiber (e.g., carbon fiber) may have a tensile modulus greater than 200 GPa, preferably greater than 230 GPa, more preferably greater than 240 GPa.

[0051] The reinforcing fibers (e.g., carbon fibers) may have a fracture strain greater than 1.1%, preferably greater than 1.2%, 1.4%, or 1.6%. The reinforcing fibers (e.g., carbon fibers) may have a fracture strain less than 2.2%, such as less than 2.0% or 1.9%. In some embodiments, the reinforcing fibers (e.g., carbon fibers) may have a fracture strain of 1.2% to 2.2%, such as 1.4% to 2.0% or 1.6% to 1.9%. In one embodiment, the reinforcing fibers (e.g., carbon fibers) may have a fracture strain of 1.7% to 1.9%.

[0052] The mass per unit length of the reinforcing fibers (e.g., carbon fibers) may be from 0.1 g / m to 1.0 g / m, such as from 0.2 g / m to 0.8 g / m. In some embodiments, from 0.2 g / m to 0.5 g / m.

[0053] The reinforcing fibers (e.g., carbon fibers) may have a density greater than 1.65 g / cm 3 , preferably greater than 1.70 g / cm 3 The reinforcing fibers (e.g., carbon fibers) may have a density less than 1.85 g / cm 3 , preferably less than 1.80 g / cm 3 The density. In some embodiments, the reinforcing fibers (e.g., carbon fibers) may have a density of 1.70 to 1.85 g / cm 3 , such as 1.75 to 1.80 g / cm 3 , or 1.78 to 1.79 g / cm 3 The density.

[0054] The reinforcing fibers (e.g., carbon fibers) may be provided in the form of continuous tows. Any suitable tow size may be used. The tow size represents the number of filaments in the tow. In some embodiments, the tow size may be from 1000 to 24,000. In one embodiment, a tow size of 6000 to 12,000 may be employed.

[0055] Examples of suitable reinforcing fibers include, for example, carbon fibers supplied by Hexcel Corporation under the trademark The supply of carbon fiber.

[0056] The reinforcing fibers (e.g., carbon fibers) may be present in an amount of 30 vol% to 68 vol%, preferably 40 vol% to 65 vol%. Preferably, based on the total volume of the composite material, the reinforcing fibers may be present in an amount of 50 vol% to 62 vol%, such as 52 vol% to 58 vol%.

[0057] Reinforcing fibers (e.g., carbon fibers) can be formed into filaments. Any suitable method can be employed. For example, the reinforcing fibers can be twisted or woven to form filaments. In the case where the composite material forms a tape, the filaments can be substantially aligned along the longitudinal axis of the tape.

[0058] The amount of reinforcing fibers (e.g., carbon fibers) in the composite material can be controlled within a narrow range so that the composite material can provide an optimized balance of mechanical properties.

[0059] In some embodiments, the composite material further contains a contrast agent, such as barium sulfate. For example, barium sulfate can be present in the composite material in an amount of 2 wt% to 20 wt% of the total weight of the composite material, such as 3 wt% to 10 wt%. In a preferred embodiment, the amount of barium sulfate can be 4 wt% to 8 wt%, more preferably 4 wt% to 6 wt%. In a most preferred embodiment, the amount of barium sulfate can be 5 wt%.

[0060] By using a controlled amount of a combination of reinforcing fibers (e.g., carbon fibers) and a contrast agent (e.g., barium sulfate), it is also possible to change the properties of the composite material in terms of, for example, imaging under X-rays. For example, although barium sulfate can provide sufficient radiopacity for an implantable device intended to be detected, for example, under X-rays, the amount of reinforcing fibers (e.g., carbon fibers) is controlled within a narrow range to provide or maintain sufficient radiolucency to allow detection of a fracture in the underlying bone under an imaging technique such as X-rays.

[0061] Furthermore, by using a controlled amount of reinforcing fibers (e.g., carbon fibers) in combination with barium sulfate, the radiopacity of the composite material can be optimized to reduce interference so that the dose accuracy during radiotherapy can be maintained.

[0062] Contrast agent

[0063] Any suitable contrast agent can be used. Preferably, the contrast agent can be detected by X-rays. In some embodiments, the contrast agent contains barium. For example, the contrast agent can be barium sulfate.

[0064] Barium sulfate is a contrast medium that allows the composite material to be detected under an imaging technique (e.g., X-rays). Thus, when the composite material is used to manufacture an implantable device, the device can be detected, for example, under X-rays.

[0065] Barium sulfate can have a D 10 particle size in the range of 0.1 micrometer to 1.0 micrometer; the D 50 particle size is in the range of 0.5 micrometer to 2.0 micrometers, and the D 90 particle size is in the range of 1.0 micrometer to 5 micrometers. The D 10The particle size can range from 0.1 micrometer to 0.6 micrometers, preferably from 0.2 micrometers to 5 micrometers. D 50 The particle size can range from 0.7 micrometer to 1.5 micrometers, preferably from 0.8 micrometer to 1.3 micrometers. D 90 The particle size can range from 1.5 micrometers to 3 micrometers, preferably from 2.0 micrometers to 2.5 micrometers.

[0066] Suitable X-ray grade barium sulfate can be purchased from Merck Millipore.

[0067] Any suitable amount of contrast agent can be used, such as barium sulfate. For example, the contrast agent (e.g., barium sulfate) can be present in the composite material in an amount of 2 wt% to 20 wt%, preferably 3 wt% to 15 wt%, such as 3 wt% to 10 wt%. In a preferred embodiment, the amount of the contrast agent (e.g., barium sulfate) can be 3 wt% to 8 wt%, more preferably 3 wt% to 5 wt% or 4 wt% to 6 wt%. In a most preferred embodiment, the amount of the contrast agent (e.g., barium sulfate) can be 5 wt%.

[0068] The amount of the contrast agent (e.g., barium sulfate) can be controlled such that the radiopacity of the composite material is optimized to reduce interference. This can allow for maintaining the dose accuracy during radiotherapy.

[0069] Furthermore, by controlling the relative amount of reinforcing fibers (e.g., carbon fibers) to barium sulfate, it is also possible to alter the properties of the composite material in terms of, for example, imaging under X-rays. For example, the relative amount of reinforcing fibers (e.g., carbon fibers) to barium sulfate can be controlled to allow detection of an implantable device under, for example, X-rays, while maintaining sufficient radiopacity to allow detection of a fracture in the underlying bone.

[0070] Furthermore, the relative amount of reinforcing fibers (e.g., carbon fibers) to barium sulfate can be controlled such that the radiopacity of the composite material is optimized to reduce interference. This can allow for maintaining the dose accuracy during radiotherapy.

[0071] Composite material

[0072] The composite material can be formed into a tape. For example, the reinforcing fibers (e.g., carbon fibers) can be combined with a polyaryletherketone (e.g., PEEK) and formed into a tape. Multiple tapes can be joined to form a layer, and the layer can be compression molded to form the compression molded body portion of the device. In one embodiment, the polyaryletherketone (e.g., PEEK) can be heated to above its softening temperature or melting temperature to melt or soften the polymer around the fibers to form the composite material. Then, the molten or softened polymer is compressed around the fibers.

[0073] When heated, suitable temperatures include 320 °C and higher temperatures, preferably 330 °C and higher temperatures, more preferably 340 °C and higher temperatures. In some embodiments, compression molding can be carried out at temperatures from 320 °C to 450 °C, preferably from 330 °C to 400 °C, more preferably from 340 °C to 380 °C, still more preferably from 350 °C to 370 °C. Suitably, a pressure of at least 1.5 MPa or at least 2 MPa can be applied. Examples of suitable pressure ranges are from 1.5 MPa to 10 MPa, such as from 2 MPa to 8 MPa.

[0074] The tape or layer formed using the composite material of the present invention can have a thickness of 10 microns to 1 mm, preferably 100 microns to 300 microns, more preferably 140 microns to 200 microns.

[0075] Device

[0076] As described above, one aspect of the present invention is a method of manufacturing a device. The method includes removing a portion of a first layer of a composite material comprising reinforcing fibers and polyaryletherketone to form a first cutout region in the first layer; bringing a second layer of the composite material into contact with the first composite material layer such that at least a portion of the second layer overlaps at least a portion of the first cutout region; and compression molding the layers of the composite material together such that some of the polyaryletherketone in the polyaryletherketone of the second layer of the composite material flows into the first cutout region.

[0077] When some of the polyaryletherketone in the polyaryletherketone of the composite material in the second layer flows into the first cutout region, the amount of polyaryletherketone in the first cutout region increases. This polyaryletherketone-rich region can form a first region of the first layer. The remaining portion of the first layer can form a second region of the first layer.

[0078] As described above, the polyaryletherketone-rich region can have enhanced flexibility and / or ductility. This can be used to reduce the risk of crack propagation and / or delamination, for example, when the molded body part is subjected to an insertion torque that might otherwise cause delamination (e.g., delamination of the outer layer of the compression molded body part) and / or cracking. Thus, in some embodiments of the method of the present disclosure, a portion of the first composite material layer can be cut away to form a cutout region that corresponds to, for example, a region of the compression molded body part of the device that is prone to cracking or other damage when the device is subjected to an insertion torque. During compression molding, the polyaryletherketone from an adjacent layer (e.g., the second layer) of the compression molded composite material can flow into the cutout region to form a polyaryletherketone-rich region in the first layer. As described above, these polyaryletherketone-rich regions provide enhanced flexibility and / or ductility to reduce the risk of damage in these regions.

[0079] The area of the compression-molded body portion of the device that is prone to cracking or other damage (e.g., when the device is subjected to insertion torque) can be the area adjacent to or surrounding a hole (e.g., a screw hole). Thus, in some embodiments, a portion of the first composite layer can be cut away to form a cutout region that corresponds to the area adjacent to or at least partially surrounding a hole (e.g., a screw hole). After compression molding, the resulting first region will be located adjacent to the hole or can at least partially define at least a portion of the hole wall. This can reduce the risk of cracking or other damage near the hole.

[0080] In some embodiments, a portion of the first composite layer can be cut away to form a cutout region that corresponds to the area extending from a hole (e.g., a screw hole) to the edge of the compression-molded body portion. Thus, the resulting first region can extend from the hole to the outer edge of the compression-molded body portion. Such a region can reduce the risk of crack formation and / or crack propagation from the hole to the outer edge of the compression-molded body portion.

[0081] In embodiments where the compression-molded body includes two or more holes (e.g., screw holes), a portion of the first composite layer can be cut away to form a cutout region that corresponds to the area connecting two or more holes (e.g., screw holes). After compression molding, the resulting first region will be located in the area extending between the two or more holes (e.g., screw holes). This can help prevent cracks from propagating between the holes (e.g., adjacent to or near the holes) in the compression-molded body portion.

[0082] The first composite layer that is cut to form the cutout region can be used to form the outer layer of the compression-molded body portion. The outer layer can form the upper surface and / or the lower surface of the compression-molded body portion. It can be desirable to have the first region present on the outer surface of the compression-molded body portion because this can reduce the risk of delamination of the outer layer of the device. Such outer layers can otherwise have an increased risk of delamination when the compression-molded body portion is subjected to insertion torque.

[0083] In some cases, the composite material may be cut out from a composite material layer stack (i.e., the overlying layer). During compression molding, the polyaryletherketone from adjacent composite material layers may flow to fill the cutout area. This forms a polyaryletherketone-rich region that is multiple layer thicknesses in the main body portion of the compression molding. The polyaryletherketone-rich region may be 2 to 10 layer thicknesses, preferably 2 to 5 layer thicknesses, more preferably 1 to 2 layer thicknesses. The number of layers may account for 50% of the thickness of the plate, more preferably less than 30% of this thickness, more preferably less than 10% of the plate thickness, but at least 1 ply. The polyaryletherketone-rich region may form part of the outer surface of the main body portion of the compression molding. By restricting the polyaryletherketone-rich region to, for example, only a portion of the main body of the compression molding (e.g., the outer layer), other functional properties of the main body can be altered / controlled by changing or controlling the material properties of the remaining layers of the main body.

[0084] As described above, the composite material layer may be formed from a composite material tape. In the case of forming layers using tapes, multiple tapes may be aligned unidirectionally in the layer. Then multiple layers of tapes may be laminated and compression molded in a ply arrangement to form a laminate, for example, in the shape of a device body. When the reinforcing fibers form filaments, the filaments may be aligned along the length of the tape. The filaments may be continuous and thus uninterrupted along the length of the tape.

[0085] In some embodiments, the tapes in the first layer may be aligned unidirectionally along an axis. The tapes in the second layer may be aligned unidirectionally at an angle to the axis of the first layer. In the third ply of the laminate, the tapes may be aligned unidirectionally at an angle different from the angles of the second and / or first layers. These layers and subsequent layers may be oriented at an angle according to the desired properties and / or shape of the device. The ply arrangement may be determined using computer software according to the shape, construction, and / or properties of the final device. The outer ply of the ply arrangement may be angled relative to the previous layer in a manner that reduces the risk of crack propagation and / or delamination.

[0086] In one example, the tapes in the first layer are aligned at 0° to the axis. The tapes in the second layer may be aligned at 90° to the axis, while the third and fourth layers may be aligned at 0° and 90° to the axis, respectively. This alternating pattern may be continuous throughout the laminate. In an alternative embodiment, the tapes in the first layer are aligned at 0° to the axis. The tapes in the second layer may be aligned at 45° to the axis, while the third layer may be aligned at 90° to the axis. The fourth layer may be aligned at -45° to the axis, and the fifth layer may be aligned at 0° to the axis, and so on. Figure 1 Examples of suitable ply arrangements for producing a laminate for a device are shown. In some examples, the orientation of the tapes in the outer ply may be aligned at an angle to the tapes in the previous ply, for example, at a right angle to the previous ply. This may help reduce the risk of cracking and / or delamination.

[0087] The tape in the ply layup can be compression molded to form the device or a part thereof. The compression molding can be carried out by heating and applying pressure. The resulting part can then be cooled, for example, under pressure.

[0088] When heated, suitable temperatures include 320 °C and higher, preferably 330 °C and higher, more preferably 340 °C and higher. In some embodiments, the compression molding can be carried out at a temperature of 320 °C to 450 °C, preferably 330 °C to 400 °C, more preferably 340 °C to 380 °C, still more preferably 350 °C to 370 °C. Suitably, a pressure of at least 1.5 MPa or at least 2 MPa can be applied. Examples of suitable pressure ranges are 1.5 MPa to 10 MPa, such as 2 MPa to 8 MPa.

[0089] In some embodiments, after heating and applying pressure, the part is rapidly cooled, preferably to a temperature between 140 °C and 200 °C. In some embodiments, the cooling can be carried out under pressure.

[0090] In some examples, the plurality of layers comprise the same polyaryletherketone (e.g., PEEK). The layers can be formed from the same composition except for a first region of the compression molded body portion having a higher polyaryletherketone content.

[0091] Some layers of the device can be free of barium sulfate, while some layers can contain barium sulfate.

[0092] In a preferred embodiment, at least one outer region (e.g., the outer surface or external surface) of the device contains barium sulfate. This can allow the use of imaging techniques (e.g., X-rays) to detect the outer region of the device. In certain cases, the inner region of the device can contain barium sulfate. In certain cases, barium sulfate can be present throughout the device.

[0093] In the case where the device has a body with a variable cross-section, the device can be formed using the method described in WO 2017 / 029476. For example, the body can be formed from a first outer layer and a second outer layer. A filler layer can be positioned between the first outer layer and the second outer layer, and an insert layer can be positioned within the filler layer to provide increased depth for a portion of the body. These layers can be compression molded together to form the body of the device. The first outer layer can contact the second outer layer to reduce exposure of the ends of the filler layer and the insert layer, thereby reducing the risk of delamination of the molded part.

[0094] The device can be a medical device. Preferably, the device can be an implantable device. Examples include orthopedic implants such as fracture plates and / or trauma plates, intramedullary nails, spinal implants such as cages, rods, and screws, and other load-bearing or bone-contact implants. In a preferred embodiment, the device is a fracture plate or a trauma plate.

[0095] The device may include one or more holes. For example, the device may include threaded holes, such as for receiving fixation screws that are used to secure the device to a underlying structure. In the case of an orthopedic implant, the device may include threaded holes for receiving screws that are used to secure the device to the underlying bone. In one embodiment, the device is an implantable implant that includes one or more threaded holes. In a preferred embodiment, the device may be a fracture plate or trauma plate that includes one or more threaded holes. The implant may be damage resistant when a relatively high insertion torque is applied.

[0096] These and other aspects of the invention will now be described with reference to the drawings.

[0097] See Figure 1 , which is a schematic illustration of an exemplary ply layup arrangement of layers of tapes formed of a composite material of an embodiment of the invention. Starting from the bottom of the ply as shown, the first layer is formed of tapes aligned unidirectionally along an axis (0°). The second layer is formed of tapes aligned unidirectionally at 45° to the axis of the first layer. The third layer is formed of tapes 14c aligned unidirectionally at -45° to the axis of the first layer. The fourth layer is formed of tapes 14d aligned unidirectionally at 90° to the axis of the first layer. The pattern is repeated such that the overall structure has the following alignment angles: 0°, 45°, -45°, 90°, -45°, 45°, and 0. The resulting laminate may be compression molded under heat and pressure to form a compression molded body portion of a device (e.g., a fracture plate).

[0098] Although not shown, a portion of the bottom layer and / or the final layer may be removed to form a cutout region corresponding to the region surrounding the threaded hole. When the laminate is compression molded, polyaryletherketone from adjacent layers flows into the cutout region, thereby forming a polyaryletherketone-rich region surrounding the threaded hole. These polyaryletherketone-rich regions provide increased flexibility and / or ductility, thereby reducing the risk of cracking and / or delamination in the outer layer of the resulting device.

[0099] Example

[0100] Reference example

[0101] Figure 2 The fracture plate template 10 schematically shown in is formed by compression molding layers of a composite material comprising PEEK and carbon fiber.

[0102] Figure 3 is a schematic illustration of how to use Figure 2 the fracture plate template 10 shown in to form a fracture plate 12. Figure 3 The outer boundary 14 in corresponds to Figure 2 the boundary of the fracture plate template 10 of. To form the fracture plate 12, Figure 2The fracture plate template 10 is cut into Figure 3 the size shown by the dashed boundary 16 in

[0103] Screws (not shown) are inserted into the screw holes 18, and an insertion torque is applied to the plate 12. The plate 12 starts to crack in the area adjacent to the screw holes 18. An insertion torque of 1.36 Nm is reached before the hole function fails (i.e., the screw is no longer secure, and the torque required to turn the screw starts to decrease). Figure 3 The arrow 20 in

[0104] Example

[0105] The above process of the reference example is repeated, except that before compressing the fracture plate template 10, a part of the outermost composite layer is cut off in Figure 4 the area "A" of Figure 4 When compressing the layer, some PEEK in the PEEK from the adjacent layers flows into the cut to form a PEEK-rich area extending between the threaded holes in the area "A" shown in

[0106] Screws (not shown) are inserted into each of the screw holes 18 and an insertion torque is applied. No cracking or delamination is observed when the hole 18 fails in function. The hole 18 is also able to withstand a higher insertion torque value before failure, where the hole fails in function at a torque of 1.8 Nm.

[0107] Definition

[0108] Note that as used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0109] As used herein, the term "about" is used to provide flexibility to range endpoints by prescribing that a given value can be "slightly higher" or "slightly lower" than the end value. The degree of flexibility of this term can be indicated by a particular variable and can be determined based on experience and the relevant description herein.

[0110] As used herein, for convenience, multiple items, structural elements, constituent elements, and / or materials may be present in a common list. However, these lists should be understood such that each individual member of the list is separately identified as a separate and unique member. Thus, in the absence of contrary indication, no individual member of such a list should be construed as a factual equivalent of any other member of the same list solely based on the fact that they appear in a common group.

[0111] Concentrations, dimensions, amounts, and other numerical data may be presented herein in a range format. It should be understood that such range formats are used merely for convenience and brevity and should be interpreted flexibly as including the numerically values explicitly recited as the limits of the range, and also including all individual values or sub-ranges subsumed within that range as if such individual values and sub-ranges were recited. For example, a weight ratio range of from about 1 wt% to about 20 wt% should be understood to include the recited limits of 1 wt% and 20 wt%, and also individual weights such as 2 wt%, 11 wt%, 14 wt%, and sub-ranges such as 10 wt% to 20 wt%, 5 wt% to 15 wt%, etc.

Claims

1. A device, the device comprising a compression molded body portion, the compression molded body portion comprising a plurality of composite material layers, the plurality of composite material layers comprising reinforcing fibers and polyaryletherketone; wherein at least one of the composite material layers has a first region and a second region, wherein the polyaryletherketone (PAEK) content in the first region is higher than the polyaryletherketone content in the second region; wherein the reinforcing fibers in the second region form continuous filaments extending in substantially the same direction, and wherein by removing a portion of the composite material, these continuous filaments are interrupted in the first region to provide a higher PAEK content to the first region.

2. The device according to claim 1, wherein the volume ratio of reinforcing fibers to PAEK in the second region is from 0.5 to 2:

1.

3. The device according to claim 1, wherein the first region is substantially free of reinforcing fibers.

4. The device according to claim 1, wherein the compression molded body portion comprises holes.

5. The device according to claim 4, wherein the holes are threaded holes.

6. The device according to claim 4, wherein the first region is adjacent to the holes.

7. The device according to claim 6, wherein the first region defines at least part of the hole wall.

8. The device according to claim 6, wherein the first region extends from the holes to the outer edge of the compression molded body portion.

9. The device according to claim 4, the device comprising at least two holes, and wherein the first region extends between the two holes.

10. The device according to any one of claims 1 to 9, wherein the composite material layer having the first region and the second region forms the outer layer of the compression molded body.

11. The device according to any one of claims 1 to 9, wherein the polyaryletherketone is polyetheretherketone (PEEK), and wherein the reinforcing fibers are carbon fibers.

12. The device according to any one of claims 1 to 9, the device being an implantable medical device.

13. The device according to claim 12, the device being a bone plate.

14. The device according to any one of claims 1 to 9, wherein the compression molded body portion comprises a composite material layer, the composite material layer comprising reinforcing fibers forming continuous filaments, the continuous filaments being interrupted in the outer layer of the compression molded body to provide a first region having a higher PAEK content to the outer layer.

15. The device according to claim 14, wherein the continuous filaments in one layer are positioned at an angle to the continuous filaments in an adjacent layer.

16. The device according to claim 14, wherein the continuous filaments in the outer layer are positioned substantially at right angles to the continuous filaments in the underlying layer.

17. A method of manufacturing a device according to any one of claims 1 to 16, the method comprising: removing a portion of a first layer of a composite material comprising reinforcing fibers and polyaryletherketone to form a first cut region in the first layer, Bring a second layer of the composite material into contact with a first layer of the composite material such that at least a portion of the second layer overlaps at least a portion of the first cutout region, and laminate the layers of the composite material together such that some of the polyaryletherketone in the second layer of the composite material flows into the first cutout region.

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