The present invention relates generally to a technique of manufacturing a shoe material, and more particularly to a method of manufacturing a multicolor-foamed shoe body by supercritical foaming and the multicolor-foamed shoe body.
Shoe material developers focus on a shoe material that is colorful and multifunctional in recent years, allowing customers to select a multicolor shoe material based on their shoe style and preference.
However, with a conventional method of manufacturing the multicolor shoe body, two shoe components are adhered manually. As the aforementioned adhering process has to carry out a complicated surface treatment with chemical primer before spreading an adhesive on a surface of the two shoe components for adhering and then heat the two shoe components in a conveyor oven to speed up the surface treatment of the chemical primer for ensuring an adhesive strength, the conventional method of manufacturing the multicolor shoe body requires a massive labor cost. Besides, the chemical primer used in the surface treatment is toxic and causes dangers to the health of workers upon prolonged exposure, and the conveyor oven causes a massive carbon dioxide emission during generating heat energy and thereby causing environmental pollution.
There are a few techniques for rectifying the defects of the conventional method of manufacturing the multicolor shoe body. For example, the China invention patent No. CN112662043A discloses a foamed shoe material with impact protection, wherein a method of manufacturing the foamed shoe material with impact protection includes following steps: injection step: a cold shot model is molded by putting plastic granules into an injection machine; foaming step: the molded cold shot model is placed in a supercritical foaming autoclave for physical foaming; molding step: a semi-finished product that is foamed is left for cooling and is disposed in a flat pressing mold for pressing to form the foamed shoe material.
The method disclosed in the aforementioned patent is to carry out supercritical foaming and then hot-pressing molding on the cold shot model to form the foamed shoe material. However, as a foaming material in the cold shot model undergoes supercritical foaming in advance, foamed waste generated during the pressing process of the semi-finished product that is foamed in the molding step is not reusable. Massive amount of foamed waste generated by the massive and daily production of the shoe material causes environmental pollution problems and thereby a huge burden to the environment.
Therefore, the conventional method of manufacturing single color & multicolor-foamed shoe body still has room for improvement.
In view of the above, the primary objective of the present invention is to provide a method of manufacturing a multicolor-foamed shoe body by supercritical foaming and the multicolor-foamed shoe body, wherein a plurality of cold shot models in different colors are engaged with one another through hot pressing to form a semi-finished product, and then the multicolor-foamed shoe body is obtained from the semi-finished product through supercritical foaming. The method could not only save costs of spreading an adhesive manually in the conventional method but also provide an environmentally friendly processing environment. Besides, the multicolor-foamed shoe body manufactured does not require additional processing and thereby does not cause waste, fulfilling the objective of sustainability development in Environmental Social Governance and increasing the yield.
The present invention provides a method of manufacturing a multicolor-foamed shoe body by supercritical foaming including following steps: step S1: provide a plurality of cold shot model molds and inject a plurality of foaming materials in different colors into a cavity of each of the cold shot model molds to form a plurality of cold shot models in different colors that is unfoamed; step S2: place the cold shot models in a hot-pressing mold for hot pressing to make a contacting surface of any two cold shot models that are adjacent engage with each other due to heating to foam a semi-finished product; and step S3: place the semi-finished product in a supercritical foaming autoclave for foam molding to obtain the multicolor-foamed shoe body.
The present invention further provides a multicolor-foamed shoe body made of a semi-finished product through supercritical foaming, wherein the semi-finished product is formed by engaging a plurality of cold shot models in different colors with one another through hot pressing. The multicolor-foamed shoe body includes a first foamed shoe component and a second foamed shoe component. The first foamed shoe component has a first engaging surface and the second foamed shoe component has a second engaging surface, wherein the second engaging surface and the first engaging surface are engaged with each other to be a monolithic unit.
With the aforementioned design, the method of manufacturing multicolor-foamed shoe body by supercritical foaming of the present invention is to firstly engage the cold shot models in different colors with one another through hot pressing. When the cold shot models are heated in the hot-pressing mold, pyrolysis in the molecular structure of each of the cold shot models occurs due to heating to engage the two adjacent cold shot models with each other to be a monolithic unit through crosslinking to form the semi-finished product. Then the multicolor-foamed shoe body is obtained from the semi-finished product via supercritical foaming. Therefore, the method could not only save costs of spreading an adhesive manually in the conventional method but also provide an environmentally friendly processing environment. Besides, the multicolor-foamed shoe body manufactured does not require additional processing and thereby does not cause waste, fulfilling the objective of sustainability development in Environmental Social Governance and increasing the yield.
Moreover, the multicolor-foamed shoe body in two or more colors could be manufactured by the method, increasing a variety of the colors of the multicolor-foamed shoe body and providing the multicolor-foamed shoe body a better appearance. Additionally, as the multicolor-foamed shoe body could have different physical properties, the multicolor-foamed shoe body manufactured by the method could be multifunctional upon the required demand.
The present invention will be best understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which
A method of manufacturing a multicolor-foamed shoe body by supercritical foaming of the present invention is illustrated in
Step S1: a plurality of cold shot model molds (not shown) is provided and a plurality of foaming materials in different colors is injected into a cavity of each of the cold shot model molds, wherein the foaming materials include rubber and plastic. When each of the foaming materials is solidified, the foaming materials are demolded from each of the cold shot model molds to form a plurality of cold shot models 10 in different colors that is unfoamed. More specifically, in the current embodiment, the cold shot models 10 are made of the same foaming material through injection molding, wherein the foaming materials are selected from a group including ethylene-vinyl acetate (EVA), synthetic rubber, polyurethane (PU), thermoplastic polyurethane (TPU), polyether block amide (PEBAX), thermoplastic vulcanizate (TPV), thermoplastic polyester elastomer (TPEE), thermoplastic polyamide elastomer (TPAE), polyolefin elastomer (POE), polypropene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), styrene-butadiene rubber (SBR), polyethylene terephthalate (PET), or thermoplastic elastomer (TPE). In an embodiment, the foaming materials could be selected from a group including ethylene-vinyl acetate (EVA), thermoplastic polyurethane (TPU), and thermoplastic elastomer (TPE).
In practice, referring to step S1, each of the foaming materials is injected under a condition that a screw temperature is controlled lower than 200 degrees Celsius, wherein the screw temperature means a temperature of the screw in the injection molding machine; when the screw temperature is higher than 200 degrees Celsius, foaming might not be completed in subsequent supercritical foaming process. The foaming materials injected could be evenly distributed in the cavity of one of the cold shot model molds (not shown) to form one of the cold shot models 10 through adjusting the injection pressure during injection. The cold shot models 10 could be a shoe upper cold shot model, a shoe sole cold shot model, a footbed cold shot model, a sole pattern cold shot model, and a shoe body cold shot model, etc. Referring to
The cold shot models 10 of the present invention are unfoamed and could have the same color and the same physical property or different colors and different physical properties based on the required demand. In the current embodiment, a difference between hardnesses of the cold shot models 10 is less than or equal to 40 degrees, wherein the hardness is measured by a Shore D durometer. In the present invention, the hardness of any object is measured the Shore D durometer. For example, a hardness of the shoe sole cold shot model 12 is greater than a hardness of the shoe upper cold shot model 11, making a multicolor-foamed shoe body 30 that is foamed multifunctional and thereby allowing a user to wear comfortably and walk stably.
Step S2: the cold shot models 10 are placed in a hot-pressing mold 100 for hot pressing to make a contacting surface of any two of the cold shot models 10 that are adjacent engage with each other due to heating to form a semi-finished product. More specifically, referring to
During the hot-pressing process, the shoe upper cold shot model 11 and the shoe sole cold shot model 12 are made of the same foaming material for injection molding. In the current embodiment, the foaming material is made of ethylene-vinyl acetate (EVA) as an example. Therefore, the shoe upper cold shot model 11 and the shoe sole cold shot model 12 are heated in the cavity to allow pyrolysis in a molecular structure of both the shoe upper cold shot model 11 and the shoe sole cold shot model 12 to occur due to heating and allow crosslinking between the shoe upper cold shot model 11 and the shoe sole cold shot model 12 that are adjacent to occur, thereby the bottom surface of the shoe upper cold shot model 11 and the top surface of the shoe sole cold shot model 12 are engaged with each other to be a monolithic unit to form the semi-finished product (not shown) that is in two colors. In other embodiments, the cold shot models 10 could be made of different foaming materials, but it is noted that the engaging effect of the cold shot models 10 through hot pressing might be affected (e.g. the engaging effect of the cold shot models 10 through hot pressing might be weakened).
Additionally, in the current embodiment, a temperature of the hot-pressing mold 100 ranges between 130 degrees Celsius and 180 degrees Celsius and a time of hot pressing ranges between 10 seconds and 800 seconds, but not limited thereto. Conditions of the hot-pressing mold 100 could be adjusted based on properties of the foaming materials, as long as the temperature of the hot-pressing mold 100 and the time of hot pressing could reach a softening temperature of the foaming materials in each of the cold shot models 10.
Step S3: the semi-finished product is placed in a supercritical foaming autoclave (not shown) for foam molding to obtain the multicolor-foamed shoe body 30, wherein the supercritical foaming autoclave is filled with a supercritical fluid. When the semi-finished product is placed in the supercritical foaming autoclave, the supercritical foaming autoclave is heated and pressurized for a period of time to make the supercritical foaming fluid infiltrate into the semi-finished product. Afterwards, the supercritical foaming autoclave is depressurized to allow physical foaming to occur in the semi-finished product to form the multicolor-foamed shoe body 30. More specifically, during a supercritical foaming process of the semi-finished product, as foaming ratios of the cold shot models 10 are different, the semi-finished product foams to form a foamed intermediate (not shown) that is in a bent state, and the multicolor-foamed shoe body 30 is formed when the foamed intermediate is cooled and remolded. In other embodiments, if a foaming ratio of each of the cold shot models 10 in the semi-finished product is the same, the semi-finished product could form the multicolor-foamed shoe body 30 at once after supercritical foaming without forming the foamed intermediate.
The multicolor-foamed shoe body 30 according to the first embodiment of the present invention is illustrated in
A multicolor-foamed shoe body 40 according to a second embodiment of the present invention is illustrated in
As shown in
With the aforementioned design, the method of manufacturing multicolor-foamed shoe body by supercritical foaming of the present invention is to firstly engages the cold shot models 10 in different colors with one another through hot pressing. As the cold shot models 10 are made of the same foaming material, pyrolysis in the molecular structure of each of the cold shot models 10 occurs due to heating when the cold shot models 10 are heated in the hot-pressing mold 100, making any two adjacent cold shot models 10 engage with each other as a monolithic unit through crosslinking to form the semi-finished product. Then the multicolor-foamed shoe body 30, 40 are obtained from the semi-finished product via supercritical foaming.
In this way, the method of manufacturing the multicolor-foamed shoe body in the embodiment could save costs of spreading an adhesive manually in a conventional method. Besides, as waste generated during the hot pressing of the cold shot models 10 in Step S2 is unfoamed, the waste could be recycled to produce the foaming material, effectively reducing unrecyclable waste generated by the method of manufacturing multicolor-foamed shoe body by supercritical foaming and providing an environmentally friendly processing environment. Additionally, the multicolor-foamed shoe body 30, 40 manufactured do not require additional processing and thereby do not cause waste, fulfilling the objective of sustainability development in Environmental Social Governance and increasing the yield.
Moreover, the multicolor-foamed shoe body 30, 40 is molded at once through physical foaming, wherein any two adjacent foamed shoe components are firmly engaged with each other through crosslinking without using any chemical agents, making the multicolor-foamed shoe body 30, 40 recyclable and environmentally friendly. In addition, in the second embodiment, the multicolor-foamed shoe body 40 could be manufactured as a shoe material in three or four colors which increases a variety of the colors of the multicolor-foamed shoe body 40 and provides the multicolor-foamed shoe body 40 a better appearance, and could have different physical properties, making the shoe body beautiful, comfortable, and multifunctional.
It must be pointed out that the embodiments described above are only some preferred embodiments of the present invention. All equivalent structures and method which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.
Number | Date | Country | Kind |
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111132658 | Aug 2022 | TW | national |