KR20080055245A - Prosthetic and manufacturing method of the same - Google Patents

Abstract

A prosthesis and a manufacturing method for the same are provided to manufacture a prosthesis by metal powder injection molding to have good durability and good treatment effects. A manufacturing method of a prosthesis includes the steps of: (S10) mixing metal powder, binder and polymer beads; (S20) molding a prosthesis molding body by injecting the metal powder, binder and polymer beads into a mold for prosthesis having a stem portion and a connection portion formed therein; (S30) removing a binder from the molded prosthesis molding body; (S40) removing the polymer by heating the prosthesis molding body at a thermal decomposition temperature; and (S50) sintering the prosthesis molding body at a sintering temperature.

Description

Prosthetics and its manufacturing method {Prosthetic and manufacturing method of the same}

1 is a perspective view showing a prosthesis for hip joints according to an embodiment of the present invention.

2 is a view showing a state of use of the prosthesis for hip joints according to an embodiment of the present invention.

3 is an SEM image showing the structure of the prosthesis according to the embodiment of the present invention.

4 is a flowchart illustrating a manufacturing process of the prosthesis according to the embodiment of the present invention.

FIG. 5 is a diagram for exemplarily describing a state in which a metal powder and a polymer bead are mixed according to a manufacturing process of a prosthesis according to an embodiment of the present invention. FIG.

6 is a view for explaining the process application temperature according to the manufacturing process of the prosthesis according to the embodiment of the present invention.

7A is a diagram for exemplarily illustrating a sintering process according to the manufacturing process of the prosthesis according to the embodiment of the present invention.

7B is a diagram for exemplarily describing a case in which voids are bonded to each other when sintering is formed according to a manufacturing process of a prosthesis according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

100 ... prosthesis

110..The stem

120. Connections

130 ... gap

The present invention relates to a prosthesis and a method for manufacturing the same, and more particularly, to a prosthesis and a method for producing the prosthesis by metal powder injection molding.

Prosthetics such as artificial joints are used to relieve and replace the joints when the bones of the joints are destroyed or damaged due to arthritis or bone tumors. This artificial joint is made of metal or synthetic resin, which is paired with an arthroplasty and a suitable head.

Prosthetic materials such as artificial joints are mainly made of stainless steel, cobalt chromium, titanium, titanium alloys and plastics, or bone cements made of metal on metal, ceramic on ceramic, and ceramics. Is used. In particular, bone cement is attached to bone well and is widely used in recent years, but has the disadvantage of being easily broken.

On the other hand, the prosthesis made of metal is not easily broken, but bones of other parts are fractured due to external impact or have a problem of not being attached to the bones well. In addition, in order for the prosthesis to be attached to the bone better, a plurality of grooves are formed on the surface of the prosthesis to increase the efficiency of prosthetic treatment by allowing the bones growing after the procedure to be mated in the grooves.

Prior arts for prostheses include US Pat. No. 6,517,583, Prosthetic hip joint having a polycrystalline diamond compact articulation surface and a counter bearing surface, issued to Pope et al. The U.S. Patent Patent discloses that the wearability of the prosthesis is improved, the friction rate is reduced, and the service life is prolonged.In addition, in the U.S. Patent Registration, the surface of the prosthesis is effectively mated after bone and prosthesis. For this purpose, it is disclosed to form grooves or ridges.

However, in the case of the US patent, the prosthesis of the metal material has a limitation of improving the adhesion force because the adhesion to the bone is improved only by forming a separate attachment groove on the surface, and additional addition for forming a separate groove. There is a problem that must go through the manufacturing process. And, in the case of bone cement, there is a problem that is easily broken after the procedure because the durability is weak as already mentioned.

The present invention is to produce a prosthesis prepared by metal powder injection molding so that the mating with the human bone after the procedure is made in the long term and continuously to the inside of the surface, and also capable of functioning as a prosthesis having excellent durability and excellent treatment effect. It is to provide a method.

The prosthesis according to the present invention is a prosthesis having a stem and a connection portion, wherein the stem portion and the connection portion are integrally metal powder injection molded and have a porosity for mating with the bone after the procedure.

The stem portion and the connecting portion may be injection molded from titanium, titanium alloy or aluminum alloy powder. The voids may be formed by thermal decomposition of polymer beads mixed with the metal powder during the metal powder injection molding. The pores may be formed of irregular size and irregular distribution.

Prosthesis manufacturing method according to the invention comprises the steps of mixing a metal powder, a binder and a polymer bead; Molding the prosthesis molded body by injecting the metal powder, the binder, and the polymer bead into a mold for the prosthesis having a stem and a connection part; Removing the binder from the molded prosthesis molded body; Heating the prosthesis molded body from which the binder is removed to a pyrolysis temperature to remove the polymer; And sintering the prosthesis molded body from which the binder and the polymer have been removed by heating to a sintering temperature.

The mixing step may be mixed in the metal powder 45 ~ 85 volume ratio, the binder 10 ~ 50 volume ratio, the polymer beads 5 ~ 30 volume ratio. The metal powder may be any one of titanium, titanium alloy, or stainless alloy. Removing the binder may heat the prosthesis molded body at 150 to 200 ° C. to remove the binder by pyrolysis. Removing the binder may remove the binder using a solvent. The pyrolysis temperature for removing the polymer may be 500 to 700 ° C., and the sintering temperature may be 1,000 to 1,600 ° C.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiment, a hip joint, which is a kind of prosthesis, will be described as an embodiment.

1 is a perspective view showing a prosthesis according to an embodiment of the present invention, Figure 2 is a view showing a state of use of the prosthesis according to an embodiment of the present invention.

Prosthesis according to an embodiment of the present invention is formed by bending at a predetermined angle on the top of the stem portion 110 and the stem portion 110 is inserted into the femur (femur; 10) during the procedure as shown in Figures 1 and 2 It is provided with a connecting portion 120. The connection part 120 is connected to a ball 30 made of metal or ceramic material, and the ball 30 is connected to a socket 20 installed in the pelvis 11.

In addition, the prosthesis 100 has numerous porosity 130 formed on the surface and the tissue itself. 3 is a SEM (electron microscope) photograph showing the structure of the prosthesis according to the embodiment of the present invention. As shown in FIG. 3, the pores 130 formed in the prosthesis 100 have a very irregular size and distribution. These voids 130 improves the adhesion of the prosthesis 100 and the bone by effectively mating the bone of the femur 170 and the prosthesis 100 after the procedure of the prosthesis 100.

That is, while the bone is sleeping after the procedure, the tissue of the bone penetrates into the cavity 130 of the prosthesis 100 to allow efficient tissue matching and attachment of the bone and the prosthesis 100 after the procedure. This matting effect enhances the treatment effect by minimizing fracture due to external impact of the bone adjacent to the prosthesis 100 after the procedure. In addition, there is an advantage that can adjust the strength of the prosthesis 100 by adjusting the amount of the voids (130).

Hereinafter, a method of manufacturing a prosthesis according to an embodiment of the present invention configured as described above will be described.

Figure 4 is a flow chart for explaining the manufacturing process of the prosthesis according to an embodiment of the present invention, Figure 5 is a state in which the metal powder and polymer beads are mixed according to the manufacturing process of the prosthesis according to an embodiment of the present invention. It is a figure for demonstrating.

The prosthesis 100 according to the embodiment of the present invention is manufactured by metal injection molding (MIM).

As shown in FIGS. 4 and 5, a step (S10) of mixing the metal powder 130, the binder 140, and the polymer beads 150 is performed. The metal powder 130 used for mixing is made of titanium or stainless alloy. And the diameter of the metal powder 130 is used that is about 10 ~ 20um.

On the other hand, the binder 140 is an instant medium to uniformly fill the metal powder 130 to the desired shape, and to maintain the shape of the injection-molded prosthesis 100 until sintering is started. Therefore, the binder 140 does not exist in the prosthesis 100 that is finally manufactured. In the exemplary embodiment of the present invention, the binder 140 may use a thermoplastic resin, a wax, or the like. That is, polyethylene, polystyrene, polypropylene, or the like may be used.

In addition to the binder 140, an additional additive may be added to make the binder 140 wet well with the metal powder. Organic additives may be used as this additive.

And the polymer bead 150 may be used ABS (acrylonitrile-butadiene-styrene) or polycarbonate (polycarbonate), polystyrene (polystyrene), polyethylene (polyethylene) and the like, the size can be carried out about 10 ~ 500um.

On the other hand, the mixing ratio of the metal powder 130, the binder 140 and the polymer bead 150 is composed of 45 to 85 volume ratio of the metal powder 130, 10 to 50 volume ratio of the binder, 5 to 30 volume ratio of the polymer beads. However, the polymer bead 150 may be adjusted in various mixing ratios according to the age group, body size, surgical site, and shape of the patient, and may be variously applied from 1 to 50 volume ratios as necessary. That is, the mixing ratio of the polymer beads 150 may be variously modified and applied because it may be manufactured and used as the replacement prosthesis 100 of other body parts as well as the femur 10 of the body.

On the other hand, the mixing step requires a mixer that exerts as much shear stress as possible so that the binder 140 can be dispersed as thin as the molecular size between the metal powder 130 and the polymer beads 150. The mixer is therefore equipped with double planetary, single screw extruder, plunger extruder, twin screw extruder and twin cam twin cam) can be used.

After the mixing step is subjected to a step (S20) of molding the prosthesis 100. Molding the prosthesis 100 is performed by forcibly injecting a mixture into a mold having a shape of the prosthesis 100 of a desired shape. And before the molding step, the mixture may be cured in the form of a pallet or granules, heated at the injector during molding to be injected into the mold while having fluidity, and then cured again to maintain the shape after molding. You can do that.

And the process conditions during molding is made for about 0.5 to 60 seconds, the injection pressure may be about 10-100MPa (megapascal), the temperature during injection may be about 150-250 ℃. However, the molding process conditions may vary depending on the mixing ratio of the binder 140 and the polymer bead 150.

Next, the molding step passes through the step S30 of removing the binder 140 included in the prosthesis molded body. 6 is a view for conceptually explaining the process applied temperature according to the manufacturing process of the prosthesis according to the embodiment of the present invention.

In the embodiment of the present invention, the removing of the binder 140 may be performed by a thermal decomposition method. The pyrolysis method is to evaporate and evaporate the binder 140 by gradual pyrolysis by gradually heating the molded body. In the pyrolysis method, the molded body is first introduced into a heating furnace. In the heating furnace, the temperature is gradually raised. When the set temperature is reached, the set temperature is maintained. At this time, the set temperature (T1) may be about 150 ~ 200 ℃, the process time may be a few minutes to several hours depending on the size of the molded body is the prosthesis (100).

In another embodiment of the step of removing the binder 140, a solvent extraction method may be used to remove the binder 140 using a solvent. The solvent extraction method is to soak the prosthesis molded body in a reservoir where the solvent is stored so that the binder 140 is dissolved and removed by the solvent.

On the other hand, when the removal of the binder 140 is completed by the pyrolysis method, the polymer beads 150 are then removed (S40). Removal of the polymer beads 150 proceeds by a pyrolysis method such as removal of the binder 140. The pyrolysis temperature T2, which is a heating temperature for pyrolysis of the polymer beads 150, may be performed for several hours in a few minutes at about 500 to 700 ° C. In the case of the polymer bead 150, the process time and the process temperature vary depending on the size of the prosthesis molded body and the type of the polymer bead 150. For example, ABS (acrylonitrile-butadiene-styrene) starts pyrolysis at about 260 ℃, polycarbonate (polycarbonate) starts at about 300 ℃. Therefore, ABS may have a longer process time than polycarbonate.

In addition, the polymer bead 150 removing step may proceed to remove the binder in one heating furnace and then continue heating to another temperature to remove the polymer bead 150, or after removing the binder 140 After moving the prosthesis molded body to a heating furnace, the polymer beads 150 may be removed.

The binder 140 removal step and the polymer bead 150 removal step may be referred to as a preliminary sintering step of gradually increasing the temperature in order to proceed to the sintering step. Proceed to (S50).

In the sintering step, the molded body from which the binder 140 and the polymer bead 150 are removed is heated to a second predetermined temperature T3 to sinter the molded body. That is, the polymer bead 150 is removed and the presintered prosthesis molded body is heated and maintained at the sintering temperature (T3) to undergo a shrinkage process through densification between the metal powders 130, thereby increasing the density of the molded body and simultaneously It is a process of obtaining a shape. At this time, since the isotropic shrinkage of the molded body proceeds, the shape of the molded body is maintained.

And the sintering temperature (T3) for performing the sintering step may be carried out to about 1,000 ~ 1,600 ℃, and continue the process time for approximately 1 to 2 hours, it can proceed by adjusting the pressurized state by hydrogen or nitrogen.

Figure 7a is a view for explaining the sintering formed by the prosthesis according to the manufacturing process according to an embodiment of the present invention illustratively, Figure 7b is a sintering formed according to the manufacturing process of the prosthesis according to an embodiment of the present invention FIG. 4 is a diagram for illustratively describing a case where gaps coupled to each other occur.

As shown in FIG. 7A, the structure of the metal powder 130 of the prosthesis molded body has a different density depending on the amount of pores, and voids 130 are formed between the metal sintered bodies. The void 130 is irregularly formed. And as shown in Figure 7b is formed in an irregular size having a variety of sizes due to the bonding of adjacent pores 130 or shrinkage of the molded body during sintering.

Therefore, since the pores 130 are effectively attached to the dense mating with the bone tissue of the patient after the procedure to obtain a higher post-operative treatment effect.

Prosthesis according to the embodiment of the present invention and the manufacturing method thereof as described above can also be manufactured as a prosthesis for artificial joints and other parts of the body, only the difference in shape and the basic configuration and manufacturing method of the present invention It may be made according to an embodiment. In addition, during the injection molding, the binder may be removed, the polymer beads may be removed, and the sintering may be performed in a different manner by modifying the process conditions or methods, and according to the size and the use, part of the manufacturing process may be different. However, if it is manufactured by metal powder injection molding for use as a prosthesis, and the voids are formed into polymer beads, it should be considered to be included in the technical scope of the present invention.

The prosthesis according to the embodiment of the present invention as described above and a method for manufacturing the same to ensure that the mating of the human bone after the procedure of the prosthesis is made from the surface to the interior of the prosthesis to improve the adhesion effect of the bone and prosthesis after the prosthesis procedure To improve the treatment effect, and to be able to perform prostheses with different pore densities according to the patient's bone tissue condition, bone size, age and type of prosthesis to be used, customized treatment is possible so that more effective prosthesis treatment There is an effect to make this possible.

Claims (11)

In the prosthesis having a stem and a connection, The stem portion and the connecting portion integrally metal injection molding, characterized in that the prosthesis (porosity) for mating (bone) with the bone after the procedure. The prosthesis of claim 1, wherein the stem and the connection part are injection molded from titanium or aluminum alloy powder. The prosthesis of claim 1, wherein the pores are formed by thermal decomposition of polymer beads mixed with the metal powder during the metal powder injection molding. 2. The prosthesis of claim 1 wherein said voids are formed of irregular size and irregular distribution. Mixing the metal powder with the binder and the polymer beads; Molding the prosthesis molded body by injecting the metal powder, the binder, and the polymer bead into a mold for the prosthesis having a stem and a connection part; Removing the binder from the molded prosthesis molded body; Heating the prosthesis molded body from which the binder is removed to a pyrolysis temperature to remove the polymer; And sintering the prosthesis molded body from which the binder and the polymer have been removed to a sintering temperature. 6. The method of claim 5, wherein the mixing comprises mixing 45 to 85 volume ratio of the metal powder, 10 to 50 volume ratio of the binder, and 5 to 30 volume ratio of the polymer beads. 6. The method of claim 5, wherein the metal powder is any one of titanium, titanium alloy, or stainless alloy. The method of claim 5, wherein the removing of the binder comprises heating the prosthesis molded body at 150 to 200 ° C. to remove the binder by pyrolysis. The method of claim 5, wherein the removing of the binder comprises removing the binder by using a dissolving agent. The method of claim 5, wherein the pyrolysis temperature is 500 ~ 700 ℃ prosthesis manufacturing method, characterized in that. 6. The method of claim 5, wherein the sintering temperature is 1,000 ~ 1,600 ℃.

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