阅读说明：本技术 一种踝足矫形器的一步成型工艺和踝足矫形器 (One-step forming process of ankle-foot orthosis and ankle-foot orthosis ) 是由 刘若鹏 赵治亚 王唯贻 于 2018-06-26 设计创作，主要内容包括：本发明公开了一种踝足矫形器的一步成型工艺和踝足矫形器,该踝足矫形器的一步成型工艺包括：步骤S1,制造模具和均压板；步骤S2,将复合材料预浸料铺贴在模具上,以及将铺贴复合材料预浸料后的模具和均压板进行组装,以得到组合件；步骤S3,对组合件依次进行抽真空处理和固化处理,其中,固化处理包括：将组合件放入到加压罐后,加压至第一预设压力；根据预设的第一温度梯度,将组合件加热至第一预设温度,并在第一时间段内保温；步骤S4,对组合件进行脱模处理,以得到踝足矫形器。本发明通过上述技术方案,从而能够节约成本,提高产值。(The invention discloses a one-step forming process of an ankle-foot orthosis and the ankle-foot orthosis, wherein the one-step forming process of the ankle-foot orthosis comprises the following steps: step S1, manufacturing a mold and a pressure equalizing plate; step S2, paving the composite material prepreg on a mold, and assembling the mold paved with the composite material prepreg and a pressure equalizing plate to obtain an assembly; step S3, performing vacuum pumping and curing treatment on the assembly in sequence, wherein the curing treatment includes: after the assembly is placed in a pressurization tank, pressurizing to a first preset pressure; heating the assembly to a first preset temperature according to a preset first temperature gradient, and preserving heat in a first time period; and step S4, demolding the assembly to obtain the ankle-foot orthosis. Through the technical scheme, the cost can be saved, and the output value can be improved.)

1. A process for forming an ankle-foot orthosis in one step, comprising:

step S1, manufacturing a mold and a pressure equalizing plate;

step S2, paving a composite material prepreg on the mold, and assembling the mold paved with the composite material prepreg and the pressure equalizing plate to obtain an assembly;

step S3, performing vacuum pumping and curing treatment on the assembly in sequence, wherein the curing treatment includes:

after the assembly is placed in a pressurization tank, pressurizing to a first preset pressure;

heating the assembly to a first preset temperature according to a preset first temperature gradient, and preserving heat for a first time period;

step S4, demolding the assembly to obtain the ankle-foot orthosis.

2. The one-step molding process according to claim 1, wherein in step S2,

and paving and pasting the composite material prepreg on a transition area of the mould in a gradual change paving mode.

3. The one-step molding process according to claim 1, wherein the curing process further comprises:

and heating the assembly to a second preset temperature according to a second preset temperature gradient, and keeping the temperature and pressure for a second time period.

4. The one-step molding process according to claim 1, wherein the curing process further comprises:

repeatedly executing the following steps: reducing the pressure in the pressurization tank to zero, vacuumizing the pressurization tank in a third time period, and introducing air into the pressurization tank in a fourth time period;

stopping circulation until the execution times are the same as the preset times;

pressurizing to a second preset pressure, heating the assembly to a third preset temperature according to a preset third temperature gradient, and preserving heat and pressure in a third time period.

5. The one-step molding process according to claim 1, wherein the vacuuming process comprises:

the assembly is placed into a vacuum bag, and the vacuum bag and a vacuum pump are connected, so that the vacuum process is performed by the vacuum pump.

6. The one-step molding process of claim 1, wherein demolding the assembly to obtain the ankle-foot orthosis comprises:

demoulding the assembly to obtain a tibia part, wherein the inner surface of the tibia part is used for being attached to the tibia of a human body;

combining the tibial portion and a foot for receiving a foot to obtain the ankle-foot orthosis.

7. The one-step forming process of claim 1, wherein the step S2 further comprises: an airfelt is laid on the surface of the caul plate in the assembly.

8. The one-step forming process according to claim 7, wherein in the step S1 of manufacturing the pressure equalizing plate,

and (3) applying the air-permeable felt to the surface of the pressure equalizing plate so as to prepare the pressure equalizing plate with the air-permeable felt.

9. The one-step molding process according to claim 1, wherein in step S2,

and sequentially paving the release agent and the composite material prepreg on the mould.

10. An ankle-foot orthosis, characterized in that it is produced by a one-step forming process of an ankle-foot orthosis according to any of claims 1 to 10.

Technical Field

The invention relates to the field of manufacturing of ankle-foot orthotics, in particular to a one-step forming process of the ankle-foot orthotics and the ankle-foot orthotics.

Background

The artificial limb and orthopedic device industry made of carbon fiber composite materials is a new application direction in the field of composite material industry. The carbon fiber composite material is an ideal material for manufacturing artificial limbs and orthoses, the product meets the relevant management requirements of the medical and bioengineering industries, the annual demand of the artificial limbs and the orthoses made of the carbon fiber composite material is 80-120 ten thousand sets at present, the sales amount is 1-1.5 hundred million dollars, and the ankle foot orthoses are typical orthoses in the field. Although carbon fiber composite prosthetic feet and orthotics have been developed, some technical problems still exist in the production and preparation of products, and most notably the problem of the carbon fiber composite products is that the products are easy to delaminate and have pores, the defects are mainly formed because the air which is wrapped in the products is not effectively exhausted in a pressurizing or vacuum mode in the preparation process, and the strength and the fatigue resistance of the products are reduced after the defects are formed, so that the service life of the products is influenced.

In order to solve this problem, different solutions have been proposed, such as replacing the composite material with a resin system, evacuating the blank in a vacuum chamber, reducing the temperature of the environment in which the blank is applied, etc., which reduce the proportion of product defects, either from the raw material or from the equipment.

However, for the manufacturing process of the orthopedic instruments, the improvement of the first-time yield of the products through the process improvement is the primary task of improving the operating environment of the operators, for example, the prior art is to use soft pressing, namely, the pressing treatment is carried out by using vulcanized silicon rubber with certain hardness and toughness, but most of the prior art uses the silicon rubber flat plate (2D), since the ankle foot orthopedic instruments from the leg column position to the ankle assume a tapered gradual change mode, namely, the ankle is wide at the upper part and narrow at the lower part, the situation that the ankle is not pressed in place by pressing the soft flat plate on the upper part is inevitable, wrinkles occur slightly, and serious accumulation of resin occurs seriously, which affects the appearance of the products. In the prior art, in order to solve the above problem, two-step molding is adopted, namely, most of prepreg is laid and adhered firstly for curing, then polishing is carried out, and finally the last two layers of prepreg are laid and cured for the second time.

An effective solution to the problems in the related art has not been proposed yet.

Disclosure of Invention

Aiming at the problems in the related art, the invention provides a one-step forming process of an ankle-foot orthosis and the ankle-foot orthosis, which abandon the pressurization of the original silica gel plate, and achieve the effect of one-step forming by selecting expandable unvulcanized silicone rubber to manufacture a pressure equalizing plate (3D) which is more attached to a forming mold, thereby improving the one-step qualification rate of products through process improvement and further improving the operating environment of operators.

The technical scheme of the invention is realized as follows:

according to one aspect of the invention, a process for forming an ankle-foot orthosis in one step is provided.

The one-step forming process of the ankle-foot orthosis comprises the following steps:

step S1, manufacturing a mold and a pressure equalizing plate;

step S2, paving the composite material prepreg on a mold, and assembling the mold paved with the composite material prepreg and a pressure equalizing plate to obtain an assembly;

step S3, performing vacuum pumping and curing treatment on the assembly in sequence, wherein the curing treatment includes: after the assembly is placed in a pressurization tank, pressurizing to a first preset pressure; heating the assembly to a first preset temperature according to a preset first temperature gradient, and preserving heat in a first time period;

and step S4, demolding the assembly to obtain the ankle-foot orthosis.

According to an embodiment of the invention, in step S2: and paving and pasting the composite material prepreg on a transition area of the mould in a gradual change paving mode.

According to one embodiment of the invention, the curing process further comprises: and heating the assembly to a second preset temperature according to a second preset temperature gradient, and keeping the temperature and pressure for a second time period.

According to one embodiment of the invention, the curing process further comprises:

repeatedly executing the following steps: the pressure in the pressurizing tank is zero, the pressurizing tank is vacuumized in a third time period, and air is introduced into the pressurizing tank in a fourth time period;

stopping circulation until the execution times are the same as the preset times;

pressurizing to a second preset pressure, heating the assembly to a third preset temperature according to a preset third temperature gradient, and preserving heat and pressure in a third time period.

According to one embodiment of the present invention, the vacuuming process includes: the assembly is placed into a vacuum bag, and the vacuum bag and a vacuum pump are connected, so that a vacuum process is performed by the vacuum pump.

According to one embodiment of the invention, demolding the assembly to obtain an ankle-foot orthosis comprises: demoulding the assembly to obtain a tibia part, wherein the inner surface of the tibia part is used for being attached to the tibia of a human body; the tibia portion and the foot portion for receiving the foot are combined to obtain an ankle-foot orthosis.

According to an embodiment of the invention, the one-step forming process further comprises: and step S5, detecting the ankle-foot orthosis through the pressurization detection device.

According to an embodiment of the present invention, step S2 further includes: an air felt is laid on the surface of the caul plate in the assembly.

According to one embodiment of the present invention, in the process of manufacturing the uniform pressure plate of step S1, the airfelt is applied to the surface of the uniform pressure plate, thereby manufacturing the uniform pressure plate with the airfelt.

According to an embodiment of the invention, in step S2: and (3) sequentially paving the release agent and the composite material prepreg on the mould.

According to another aspect of the invention, an ankle-foot orthosis is provided.

The ankle-foot orthosis comprises: the ankle foot orthosis is manufactured by one-step molding process of any one of the ankle foot orthotics.

The invention has the beneficial technical effects that:

the method comprises the steps of manufacturing a mould and a pressure equalizing plate, then paving and pasting the composite material prepreg on the mould, assembling the mould and the pressure equalizing plate after paving and pasting the composite material prepreg to obtain an assembly, and then sequentially carrying out vacuum pumping treatment and curing treatment on the assembly, wherein the curing treatment comprises the following steps: after the assembly is placed in a pressurization tank, pressurizing to a first preset pressure; according to a preset first temperature gradient, the combined part is heated to a first preset temperature, heat preservation is carried out in a first time period, finally demoulding treatment is carried out on the combined part, so that the ankle-foot orthosis is obtained, the cost can be saved, the production value is improved, compared with the existing original two-step curing forming, the improved one-step forming process saves half of the pot consumption in the aspect of autoclave use, meanwhile, in the aspect of materials, auxiliary materials such as an air felt, an isolation film, a PE film and a vacuum bag used in the original first curing are saved, in the aspect of personnel, the one-step polishing process is also reduced, the labor cost is saved, in addition, the work of one-step bag packing and demoulding of a paving personnel is also saved, the time is saved, and the work efficiency is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a flow chart of a one-step forming process for an ankle-foot orthosis according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of various steps in a one-step forming process for an ankle-foot orthosis, according to an embodiment of the invention;

FIG. 3 is an isolated schematic view of an assembly according to an embodiment of the invention;

fig. 4 is a flow chart of a one-step forming process for an ankle-foot orthosis according to an embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

According to an embodiment of the invention, a one-step forming process for an ankle-foot orthosis is provided.

As shown in FIG. 1, a one-step forming process of an ankle-foot orthosis according to an embodiment of the invention includes: step S101, manufacturing a mold and a pressure equalizing plate; step S103, paving and pasting the composite material prepreg on a mold, and assembling the mold with the laid composite material prepreg and a pressure equalizing plate to obtain an assembly; step S105, carrying out vacuum-pumping treatment and curing treatment on the assembly in sequence, wherein the curing treatment comprises the following steps: after the assembly is placed in a pressurization tank, pressurizing to a first preset pressure; heating the assembly to a first preset temperature according to a preset first temperature gradient, and preserving heat in a first time period; and step S107, demolding the assembly to obtain the ankle-foot orthosis.

By means of the technical scheme, the composite material prepreg is laid and attached to the mold after the mold and the pressure equalizing plate are manufactured, the mold with the composite material prepreg laid and attached is assembled with the pressure equalizing plate to obtain an assembly, and then the assembly is subjected to vacuumizing treatment and curing treatment in sequence, wherein the curing treatment comprises the following steps: after the assembly is placed in a pressurization tank, pressurizing to a first preset pressure; according to a preset first temperature gradient, the combined part is heated to a first preset temperature, heat preservation is carried out in a first time period, finally demoulding treatment is carried out on the combined part, so that the ankle-foot orthosis is obtained, the cost can be saved, the production value is improved, compared with the existing original two-step curing forming, the improved one-step forming process saves half of the pot consumption in the aspect of autoclave use, meanwhile, in the aspect of materials, auxiliary materials such as an air felt, an isolation film, a PE film and a vacuum bag used in the original first curing are saved, in the aspect of personnel, the one-step polishing process is also reduced, the labor cost is saved, in addition, the work of one-step bag packing and demoulding of a paving personnel is also saved, the time is saved, and the work efficiency is improved.

In order to better describe the technical solution of the present invention, the following detailed description is made by specific examples.

As shown in fig. 2, the steps of the one-step forming process of the ankle-foot orthosis include: step S21, first, cutting and laying a prepreg; step S22, pre-compacting the laid prepreg, which may be pre-compacted in a manner of assembling a mold; step S23, packaging the assembled mold, such as loading the packaged mold into a vacuum bag, and performing vacuum treatment by a vacuum extractor; step S24, curing treatment is carried out subsequently, for example, curing treatment is carried out under the conditions that the curing temperature is 130 ℃ and the pressure is 0.3 MPa; step S25, demolding the solidified mould, and polishing; and step S26, detecting the finished product.

In addition, cutting, laying, pre-compacting and packaging of the prepreg and the adhesive film are carried out in a clean room, the indoor temperature is 22 +/-4 ℃, the relative humidity is 30-65%, the cleanliness of indoor air is not more than 10 dust particles with the particle size of 10 mu m or more, the indoor positive pressure difference corresponding to the outdoor pressure is 10-40 pa, in addition, the curing temperature is 130 ℃, the pressure is 0.3MPa, the polishing and the inspection are carried out in a common working room, the temperature is 15-32 ℃, the relative humidity is less than 75%, good ventilation facilities are needed in the room, in addition, although ranges of parameters for the steps of the one-step molding process for an ankle-foot orthosis are shown above, it will be appreciated by those skilled in the art that, the parameter range can also be set according to actual requirements, for example, according to an embodiment of the present invention, the curing temperature is 150 ℃, and the present invention is not limited thereto.

In addition, the equipment needed for cutting, laying, pre-compacting and packaging the prepreg and the adhesive film comprises an automatic blanking machine, an oven and a vacuum extractor, in addition, an autoclave is needed for curing, and a universal testing machine and a grinding machine are needed for grinding and inspection.

In addition, as shown in fig. 3, the forming mold comprises a male mold 1 and a pressure equalizing plate 2, the pressure equalizing plate 2 has the same shape as the male mold 1 and can have good fitting property with the male mold 1, and the back surface of the pressure equalizing plate 2 is provided with a small ground hole connected with the male mold 1. In addition, the uniform pressure plate 2 with the better die bonding performance avoids the defects that pressure transmission is reduced progressively and pits appear on the surface of a manufactured part and the like due to bridging at the pits in the pressurizing process. In addition, the manufacturing process of the uniform pressure plate 2 is complicated, and the uniform pressure plate cannot be directly turned over on a mold, because the uniform pressure plate is small in size due to the fact that the uniform pressure plate is directly turned over on the mold due to the curvature problem, and therefore the uniform pressure plate needs to be turned over on a polished scrapped orthosis support. Meanwhile, an autoclave is selected for molding the pressure equalizing plate 2, the temperature of the process is 160 ℃, the time is 3 hours, and the pressure is 0.4 MPa. In addition, the surface of the pressure equalizing plate 2 can be pasted with the breathable felt in the forming process, so that the strength and the hardness of the pressure equalizing plate can be improved. In addition, the person skilled in the art can set the size of the male mold 1 according to the size of the ankle-foot orthosis required, without the invention being limited thereto. In addition, the curvature of the special-shaped piece at a plurality of positions of the product is greatly changed, so that conditions are provided for defects possibly generated by stress concentration, bridging and the like, soft pressurization is not enough to be selected alone, and a proper pressurizing soft mold needs to be selected according to the difference of the positions of the molds.

In order to better describe the technical solution of the present invention, it is described in detail by specific three embodiments in conjunction with fig. 4.

First embodiment

Referring to fig. 4, in the present embodiment, the mold 1 is provided with an opening for vacuum pumping, and the one-step forming process of the ankle-foot orthosis includes:

step A: manufacturing a male mold 1 and a pressure equalizing plate 2 of the mold shown in fig. 3 according to the shape of the product;

and B: cutting and paving the prepreg on the male die 1 with the demolding cloth according to the paving process requirement;

and C: the caul plate 2 is riveted to the male mould 1 to obtain an assembly, and furthermore, an air felt is laid on the surface of the caul plate in the assembly, and the assembly is placed in a vacuum bag, and the vacuum bag is connected to a vacuum pump, so that the vacuuming is performed by the vacuum pump, for example, according to an embodiment of the present invention, at least 15 minutes under a condition of-0.95 Bar, thereby removing air between the male mould 1 and the prepreg while shaping. In addition, it is understood that, although the embodiment shows that the pressure equalizing plate 2 is connected with the male die 1 by rivets, a person skilled in the art may select other movable connection modes of the pressure equalizing plate 2 and the male die 1 according to actual requirements, and the invention is not limited thereto;

step D: heating the assembly to a first predetermined temperature according to a predetermined first temperature gradient, e.g., according to one embodiment of the invention, heating the mold to a predetermined temperature of 130 ℃ at 1 ℃/min;

step E: after the assembly is placed in the pressurization tank, pressurizing to a first preset pressure, for example, according to an embodiment of the invention, placing the assembly in the pressurization tank, pressurizing to 0.3MPa, and maintaining the temperature and pressure for 120min under the conditions of step D and step E;

step F: and heating the mold according to a curing curve, curing the resin, and demolding.

In addition, although the sequence of step D and step E is shown in this embodiment, it should be understood by those skilled in the art that the sequence of step D and step E can be adjusted, for example, according to an embodiment of the present invention, the pressurizing treatment is performed first, then the heating treatment is performed, and then the heat and pressure are maintained for 120min, and the present invention is not limited thereto.

In the present embodiment, specific parameters of the vacuum treatment and the heating and pressurizing are shown, but those skilled in the art can set the parameters of the vacuum treatment and the heating and pressurizing according to actual needs, and the present invention is not limited thereto.

Second embodiment

In this embodiment, the forming process of the composite material product is substantially the same as that of the first embodiment, except that: the phenomenon of leg piece fracture in the later use of the product due to obvious stress concentration generated by the larger steps is increased, so that the change of the prepreg paving process is increased in the step B, the overlarge steps in the transition region are prevented, and the stress concentration at the gradual change position is reduced. Referring to fig. 4, the one-step forming process of the ankle-foot orthosis comprises the following steps:

step A: manufacturing a male die 1 and a pressure equalizing plate 2 of the die according to the shape of a product;

and B: cutting and paving the prepreg on a male die 1 with demolding cloth according to the paving process requirement, wherein the ankle-foot orthosis comprises: a tibial portion and a foot portion 4 connected to the tibial portion, the inner surface of the tibia being for engaging a human tibia, the foot portion being for receiving a human foot. Wherein, the shin part is the prepreg obtained after demoulding treatment. Meanwhile, referring to fig. 3, the transition area 5 and the middle turning area 6 of the tibia portion are thickened areas, and prepreg is spread and attached in a gradual layering mode to thicken the transition area 5 and the middle turning area 6, that is, a plurality of layers with gradually changing sizes from a bottom layer to a top layer are arranged on the transition area 5 and the middle turning area 6, so that the thickness of the transition area 5 and the middle turning area 6 is uniform, and the transition at the surface turning is uniform;

and C: the caul plate 2 is riveted to the male mould 1 to obtain an assembly, and furthermore, an air felt is laid on the surface of the caul plate in the assembly, and the assembly is placed in a vacuum bag, and the vacuum bag is connected to a vacuum pump, so that the vacuuming is performed by the vacuum pump, for example, according to an embodiment of the present invention, at least 15 minutes under a condition of-0.95 Bar, thereby removing air between the male mould 1 and the prepreg while shaping. In addition, it is understood that, although the embodiment shows that the pressure equalizing plate 2 is connected with the male die 1 by rivets, a person skilled in the art may select other movable connection modes of the pressure equalizing plate 2 and the male die 1 according to actual requirements, and the invention is not limited thereto;

step D: heating the assembly to a first predetermined temperature according to a predetermined first temperature gradient, e.g., according to one embodiment of the invention, heating the mold to a predetermined temperature of 130 ℃ at 1 ℃/min;

step E: after the assembly is placed in the pressurization tank, pressurizing to a first preset pressure, for example, according to an embodiment of the invention, placing the assembly in the pressurization tank, pressurizing to 0.3MPa, and maintaining the temperature and pressure for 120min under the conditions of step D and step E;

step F: and heating the mold according to a curing curve, curing the resin, and demolding.

In addition, although the sequence of step D and step E is shown in this embodiment, it should be understood by those skilled in the art that the sequence of step D and step E can be adjusted, for example, according to an embodiment of the present invention, the pressurizing treatment is performed first, then the heating treatment is performed, and then the heat and pressure are maintained for 120min, and the present invention is not limited thereto.

In the present embodiment, although specific parameters of the vacuum treatment and the heating and pressurizing are shown, those skilled in the art can set the parameters of the vacuum treatment and the heating and pressurizing according to actual needs, and the present invention is not limited to this.

Third embodiment

In this embodiment, the forming process of the composite material product is substantially the same as that of the first embodiment, except that: and D, increasing the temperature gradient in the step D, and keeping the temperature and pressure according to the temperature gradient, so that the infiltration degree of the resin is further improved in the curing stage, the product can be more compact, and the product with a complex structure can be manufactured. Referring to fig. 4, the one-step forming process of the ankle-foot orthosis comprises the following steps:

step A: manufacturing a male mold 1 and a pressure equalizing plate 2 of the mold shown in fig. 3 according to the shape of the product;

and B: and cutting and paving the prepreg on the male die 1 with the demolding cloth according to the laying process requirement. Referring to fig. 3, the transition area 5 and the middle turning area 6 of the tibia portion are thickened by adopting a gradual layering mode, so that the thickness of the transition area 5 and the thickness of the middle turning area 6 are uniform, and the transition at the surface turning is uniform;

and C: the caul plate 2 is riveted to the male mould 1 to obtain an assembly, and furthermore, an air felt is laid on the surface of the caul plate in the assembly, and the assembly is placed in a vacuum bag, and the vacuum bag is connected to a vacuum pump, so that the vacuuming is performed by the vacuum pump, for example, according to an embodiment of the present invention, at least 15 minutes under a condition of-0.95 Bar, thereby removing air between the male mould 1 and the prepreg while shaping. In addition, it is understood that, although the embodiment shows that the pressure equalizing plate 2 is connected with the male die 1 by rivets, a person skilled in the art may select other movable connection modes of the pressure equalizing plate 2 and the male die 1 according to actual requirements, and the invention is not limited thereto;

step D: heating the assembly to a first preset temperature according to a preset first temperature gradient, heating the assembly to a second preset temperature according to a preset second temperature gradient, and maintaining the temperature and pressure for a second period of time, for example, according to one embodiment of the present invention, heating the mold to a preset temperature of 50 ℃ at 1 ℃/min, maintaining the temperature for 60min, heating the mold to a preset temperature of 130 ℃ at 1 ℃/min, and maintaining the temperature and pressure for 120 min;

step E: after the assembly is placed in the pressurization tank, pressurizing to a first preset pressure, for example, according to an embodiment of the invention, placing the assembly in the pressurization tank, pressurizing to 0.3MPa, and maintaining the temperature and pressure for 120min under the conditions of step D and step E;

step F: and heating the mold according to a curing curve, curing the resin, and demolding.

In addition, although the sequence of step D and step E is shown in this embodiment, it should be understood by those skilled in the art that the sequence of step D and step E can be adjusted, for example, according to an embodiment of the present invention, the pressurizing treatment is performed first, then the heating treatment is performed, and then the heat and pressure are maintained for 120min, and the present invention is not limited thereto.

In the present embodiment, although specific parameters of the vacuum treatment and the heating and pressurizing are shown, those skilled in the art can set the parameters of the vacuum treatment and the heating and pressurizing according to actual needs, and the present invention is not limited to this.