KR20230017401A - Multiple injection molding method and apparatus for manufacturing multi-function sole - Google Patents

Abstract

The present invention relates to a multiple injection molding method for manufacturing multi-function soles. Specifically, the multiple injection molding method comprises: a raw material mixing step of mixing raw materials containing at least one of zinc oxide, stearic acid, and calcium carbonate with EVA resins polymerized with vinyl acetate monomers and ethylene monomers; an additive injection step of controlling the physical properties of the multi-function soles by adding an additive containing at least one of a foaming agent and a crosslinking agent to a mixture obtained by performing the raw material mixing step; a processing step of processing a composition obtained after performing the additive input step by a processing method including at least one of pellet processing and rolling processing; and a molding step of molding the processed composition by injecting the composition into a prepared mold by using an injection machine, wherein in the molding step, molded articles demolded from an upper mold, middle mold, and lower mold using the composition are foamed under preset molding conditions to obtain an integrally bonded foam. According to one embodiment of the present invention, a complicated adhesion process is not required to manufacture the multi-function soles, thereby simplifying the process and reducing process costs.

Description

Multiple injection molding method and apparatus for manufacturing multi-function sole {MULTIPLE INJECTION MOLDING METHOD AND APPARATUS FOR MANUFACTURING MULTI-FUNCTION SOLE}

The present invention relates to a multi-injection molding method and apparatus for manufacturing a multi-function sole, and specifically, to a sole manufacturing technology that promotes process simplification with a multi-injection process by replacing the complicated remolding process used in the conventional sole manufacturing process. will be.

Shoes are manufactured for the purpose of firmly supporting feet on the floor, preventing loss of kinetic energy, and enabling smooth walking.

In general, shoes are composed of various types of parts based on uppers and outsole, and uppers are manufactured by sewing and bonding processes of fabric or leather products. Various parts such as airbags, shock absorbing pads, and internal reinforcing materials are individually manufactured and manufactured into a single outsole through a complex bonding process.

On the other hand, in order to improve the prior art including such a complicated bonding process, Korean Patent Publication No. 10-2011-0047343 (shoes with cushioning function) combines the outsole of a shoe by inserting a functional part into a basic part. has been proposed, but this manufacturing method had a limitation that the number of processes could not be simplified because it had to go through a complicated bonding process instead of the bonding process, and in addition, during mass production of the product, adhesion between each part was poor, resulting in actual manufacturing site There was a problem that the use of an adhesive to increase the adhesion between each part was inevitable.

Accordingly, the present invention provides a multi-injection molding method and apparatus for manufacturing a multi-function sole, thereby replacing the complex re-molding process used in the conventional sole manufacturing process and simplifying the process with a multi-injection process. To provide a sole manufacturing technology It has a first purpose.

In addition, a second object of the present invention is to provide a sole manufacturing technology capable of implementing various functionalities and designs by solving the problem of interfacial adhesion between different materials.

In order to achieve the above object, the multiple injection molding method for manufacturing a multi-function sole according to an embodiment of the present invention is an EVA resin obtained by polymerizing Vinyl Acetate Monomer (VAM) and Ethylene Monomer. A raw material mixing step of mixing a raw material including at least one of zinc oxide, stearic acid, and calcium carbonate; adding an additive including at least one of a foaming agent and a crosslinking agent to the mixture obtained by performing the raw material mixing step to control the physical properties of the multi-function sole; A processing step of processing the composition obtained after performing the additive input step by a processing method including at least one of pellet processing and rolling processing; And, a molding step of injecting and molding the processed composition into a prepared mold using an injection molding machine; including, but, in the molding step, the molded articles demolded from the upper mold, the middle mold, and the lower mold using the composition are molded under predetermined molding conditions. It is characterized in that it is foamed so that an integrally bonded foam is obtained.

In addition, in the above-described molding step, the composition is used to create a high elasticity foam in the upper mold, a shock absorbing foam in the middle mold, and a support foam in the lower mold, wherein silicone rubber is further added to the composition for the high elasticity foam, and the shock absorbing foam It is preferable to further add active zinc oxide to the composition.

In addition, when performing the above molding step, different molding temperatures are set for the upper mold, the middle mold, and the lower mold, the molding temperature of the high elasticity foam is 166 to 192 ° C, and the molding temperature of the shock absorbing foam is 104 to 140 ° C. , The molding temperature of the support foam is preferably made in the temperature range of 166 to 192 ℃.

In addition, in the above-described molding step, after disposing the high elasticity foam, shock absorbing foam, and support foam generated in the upper mold, the middle mold, and the lower mold at predetermined positions, they are subjected to 30° C. at a temperature of 165 to 180 ° C. using a thermal compression press. to 100 kgf/cm ² and press-molding for 8 to 11 minutes is preferred.

In addition, the above-described processing step is preferably such that the composition is subjected to processing including at least one of pellet processing and rolling processing having a thickness of 10 to 24 mm.

In addition, in the step of adding the above additive, it is preferable to use a JTR foaming agent containing at least azobisformamide as a foaming agent and a peroxide crosslinking agent containing at least dicumyl peroxide (DCP) as a crosslinking agent.

In addition, in the above-described raw material mixing step, the content of vinyl acetate (VA, Vinyl Acetate) in the EVA resin is 9.3 to 28.0% by weight, and 3 to 7 parts by weight of zinc oxide and stearic acid are used per 100 parts by weight of the EVA resin. It is preferable to include 0.5 to 2 parts by weight of calcium carbonate and 7 to 12 parts by weight.

On the other hand, the multi-injection molding device for manufacturing a multi-function sole uses at least one of zinc oxide, stearic acid, and calcium carbonate in an EVA resin obtained by polymerizing a vinyl acetate monomer and an ethylene monomer. A hopper in which a mixture of raw materials including a is stored; a mold provided as an upper plate mold, a middle plate mold, and a lower plate mold; an injection machine provided with a heating cylinder and supplying the raw material mixture stored in the hopper to the mold in a plasticized state; A press machine for thermally compressing the moldings demolded from the mold; And, a controller for controlling the operation of components including at least one of a hopper, a mold, an injection machine, and a press machine.

In addition, the mold described above is preferably provided with a structure in which the middle plate mold is inserted between the upper plate mold and the lower plate mold.

In addition, the heating temperature of the above-described heating cylinder is variably controlled according to the mold to which the raw material mixture is supplied. When the raw material mixture is supplied to the upper plate mold, a temperature of 166 to 192 ° C is set, and when the raw material mixture is supplied to the middle plate mold, A temperature of 104 to 140 ° C is set, and when supplying the raw material mixture to the lower plate mold, it is preferable to set a temperature of 166 to 192 ° C.

According to an embodiment of the present invention, it is possible to provide a sole manufacturing technology that can simplify the process with a multi-injection process by replacing the complex remolding process used in the conventional sole manufacturing process, and at the same time, different materials There is an effect of providing a sole manufacturing technology capable of implementing various functionalities and designs by solving the problem of interfacial adhesion between the surfaces.

In addition, according to an embodiment of the present invention, a complicated bonding process is not required to manufacture a multi-function sole, thereby simplifying the process and reducing process costs, and in addition, the use of adhesives reduces the amount of environmentally harmful substances. It has the effect of significantly reducing emissions.

1 is a flow chart of a multi-injection molding method for manufacturing a multi-function sole according to an embodiment of the present invention.
Figure 2 is an example of an EVA formulation table that becomes the parent of a support foam, a high elasticity foam, and a shock absorbing foam according to an embodiment of the present invention.
3 is an example of experimental results for crosslinking characteristics according to temperature when mixing raw materials according to an embodiment of the present invention.
Figure 4 is an example of a blending characteristic table of each functional molding constituting the multi-function sole according to an embodiment of the present invention.
5 is an example of experimental results for an adhesion test according to molding conditions according to an embodiment of the present invention.
6 is an example of a configuration diagram of a multiple injection molding apparatus for manufacturing a multi-function sole according to an embodiment of the present invention.
7 is an example of a mold structure of a multi-injection molding apparatus for manufacturing a multi-function sole according to an embodiment of the present invention.
8 is a product appearance photograph of a multi-function sole manufactured according to an embodiment of the present invention.
9 is a test report for a multi-function sole product manufactured according to an embodiment of the present invention.

In the following, various embodiments and/or aspects are disclosed with reference now to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to facilitate a general understanding of one or more aspects. However, it will also be appreciated by those skilled in the art that such aspect(s) may be practiced without these specific details. The following description and accompanying drawings describe in detail certain illustrative aspects of one or more aspects. However, these aspects are exemplary and some of the various methods in principle of the various aspects may be used, and the described descriptions are intended to include all such aspects and their equivalents.

References to “embodiment,” “example,” “aspect,” “example,” etc., used in this specification should not be construed as indicating that any aspect or design described is preferable to or advantageous over other aspects or designs. .

Also, the terms "comprises" and/or "comprising" mean that the feature and/or element is present, but excludes the presence or addition of one or more other features, elements and/or groups thereof. It should be understood that it does not.

In addition, terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

In addition, in the embodiments of the present invention, unless otherwise defined, all terms used herein, including technical or scientific terms, are those commonly understood by those of ordinary skill in the art to which the present invention belongs. have the same meaning. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the embodiments of the present invention, an ideal or excessively formal meaning not be interpreted as

The present invention relates to a multi-injection molding method for manufacturing a multi-function sole, and provides a multi-injection molding method and apparatus for manufacturing a multi-function sole, thereby replacing the complicated remolding process used in the conventional sole manufacturing process with a multi-injection process. The first purpose is to provide a sole manufacturing technology that can promote process simplification, and the second purpose is to provide a sole manufacturing technology that can implement various functionalities and designs by solving the problem of interfacial adhesion between different materials.

Hereinafter, a more detailed description of the present invention will be performed with reference to the accompanying drawings, and a plurality of drawings may be simultaneously referenced to describe one technical feature and components constituting the invention.

Referring first to FIG. 1 , FIG. 1 is a flowchart of a multi-injection molding method for manufacturing a multi-function sole according to an embodiment of the present invention.

As shown in FIG. 1, in the present invention, zinc oxide, stearic acid and carbonic acid are added to the EVA resin obtained by polymerizing Vinyl Acetate Monomer (VAM) and Ethylene Monomer. A raw material mixing step (S10) of mixing a raw material including at least one of calcium (Calcium Carbonate) may be performed.

Specifically, the above-described EVA is an abbreviation of ethylene-vinyl acetate, and is a copolymer of ethylene and vinyl acetate, and is characterized in that physical properties change depending on the content of vinyl acetate.

Referring to Figure 2 for a while, Figure 2 shows a composition table of EVA foam, which is the parent of the EVA blend of the present invention to be described below. In the present invention, the composition of the polymer is changed based on the composition table of FIG. want to grant

Looking at the formulation table of the parent EVA foam shown in FIG. 2, it can be seen that zinc oxide, stearic acid, and titanium dioxide are used as other additives. At this time, it will be understood that the above-mentioned zinc oxide is added as a foam initiator. , It will be understood that the above-mentioned stearic acid is added as a release agent for promoting crosslinking of the foam and facilitating release, and the above-mentioned titanium dioxide is added for the purpose of increasing color expression by improving whiteness. can be understood

In addition, in FIG. 2, it can be seen that dicumyl peroxide (DCP, Dicumyl peroxide), one of the peroxide crosslinking agents, is used as a crosslinking agent, and JTR foaming agent is used as a foaming agent. The higher the content, the faster the crosslinking rate and the higher the crosslinking density, resulting in a decrease in the foaming ratio.

In addition, when the EVA foam was produced using EVA alone, the foaming ratio was 156 to 173%, and the foaming ratio tended to increase as the content of vinyl acetate decreased, and the specific gravity increased as the foaming ratio increased. It was found that the hardness decreased as the crosslinking density decreased, and the tensile strength, tear strength, and elongation tended to decrease as the content of vinyl acetate decreased, and as the content of vinyl acetate increased, the elasticity increased. It was found that the rebound resilience was improved as the content of vinyl acetate increased.

In addition, as the content of vinyl acetate decreased, the melting point increased, and it was found that the heat shrinkage rate of the foam improved as the content of vinyl acetate decreased. The lower the melt index (MI) of vinyl acetate, the higher the resistance to mold deformation. It was found to have excellent resilience.

In other words, when EVA foam was produced using EVA alone, the properties such as thermal shrinkage and permanent set were excellent, but other resins that can compensate for the disadvantages of EVA to improve mechanical strength due to high hardness and specific gravity It was predicted that a blend with

Therefore, in the present invention, calcium carbonate, which can improve mechanical strength at a low cost, is added as a substitute raw material for titanium dioxide to form an EVA blend containing EVA resin, zinc oxide, stearic acid and calcium carbonate. The EVA blend mentioned in the invention contains 3 to 7 parts by weight of zinc oxide, 0.5 to 2 parts by weight of stearic acid, and 7 to 12 parts by weight of calcium carbonate per 100 parts by weight of EVA resin (most preferably 100 parts by weight of EVA resin). 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, and 10 parts by weight of calcium carbonate).

More specifically, the EVA resin included in the above-described EVA blend is preferably used in a vinyl acetate content of 9.3 to 28.0% by weight. When blended with calcium, it will be understood that the degree of crosslinking is easy to control, so that the blending stability is within the content range determined to be suitable for mass production of the product.

On the other hand, after the above-described step S10 is performed, an additive including at least one of a foaming agent and a crosslinking agent is added to the mixture obtained by performing the step S10 to control the physical properties of the multi-function sole An additive input step (S20) is performed It can be.

As an example, in the above-described step S20, a JTR-based foaming agent containing at least azobisformamide is used as a foaming agent, and at least dicumyl peroxide (DCP, Dicumyl peroxide) as a crosslinking agent. A peroxide crosslinking agent containing is used. Specifically, the above-described foaming agent may be added at 1.5 to 4.8 parts by weight per 100 parts by weight of the EVA resin, and the above-mentioned crosslinking agent may be added at 0.5 to 1.9 parts by weight of the EVA resin.

Meanwhile, after performing the above-described step S20, a processing step (S30) of processing the composition obtained after performing step S20 by a processing method including at least one of pellet processing and rolling processing is performed.

Preferably, in step S30 described above, the composition is preferably subjected to processing including at least one of pellet processing and rolling processing having a thickness of 10 mm to 24 mm, and when pellet processing is performed, the composition is formed into a pellet type , it will be understood that the composition is processed into a sheet type when rolling processing is performed.

At this time, it will be understood that the above-described thickness range is a value derived as a thickness range having the best CS characteristics in a number of permanent set experiments (50 ° C / 6 hours).

In addition, in the above-described step S30, the composition has been described as being limited to processing the composition into a type including at least one of a pellet type and a sheet type, but such processing types include various types of processing such as bead type and ball type. It can be modified and modified and used.

Meanwhile, after the above-described step S40 is performed, a molding step (S50) of molding the processed composition by injecting it into a prepared mold using an injection molding machine is performed.

Specifically, the above-described step S50 foams the moldings demolded (or released) from the upper mold, the middle mold, and the lower mold using the composition under predetermined molding conditions to obtain an integrally combined foam. The process is performed Preferably, more preferably, using the above-described composition, a high-elasticity foam to which a high-elasticity function is assigned is produced in the upper mold, a shock-absorbing foam to which a function to absorb shock is imparted in the middle mold, and a support foam in the lower mold. It is preferable to

However, in order to mold the foam with the above-described functions, additional raw materials may be required to be added to the above-described composition, and in the present invention, silicone rubber (eg CF201U) is added to the above-described composition to produce a high-elasticity foam. Further addition (preferably, active zinc oxide may be further added to the above composition in an amount of 3.5 to 5 parts by weight per 100 parts by weight of the EVA resin to prepare a shock absorbing foam.

On the other hand, in the injection machine, the above-mentioned composition is melted by a heating cylinder and supplied to the mold. In the present invention, it is preferable to melt at a temperature of 171 to 179 ° C, most preferably 175 ° C, such a melting temperature This is because the crosslinking time can be shortened by about 20 to 24% compared to the temperature of 170 ° C., which is a temperature condition commonly used for injection molding, and the degree of uniformity of the expansion ratio can be increased by reducing the crosslinking deviation.

The experimental results for this are attached to FIG. 3, and from the experimental result data of A and B of FIG. 3, when the melting temperature is 175 ° C., the crosslinking density is established at a level capable of providing high elasticity, and the crosslinking time is greatly shortened. can confirm that it is.

Returning to FIG. 1, in the present invention, when performing step S50, it is preferable to set the molding conditions to different conditions for each mold to solve the interfacial adhesion problem, which is that the EVA blend composition is injected for each mold It will be understood that this is a method for solving the problem that adhesion between interfaces is not completely achieved due to a change in crosslinking rate due to time difference and separation between interfaces occurs.

Specifically, the injection molding conditions established by the applicant by performing a number of experiments are, in the case of high elasticity foam, the upper mold has a temperature range of 166 to 192 ° C (most preferably 179 ° C) so that injection molding is performed Preferably, in the case of shock absorbing foam, it is preferable to have the middle plate mold have a temperature range of 104 to 140 ° C. (most preferably 117 ° C.) so that injection molding is performed, and in the case of the support foam, the lower plate mold is 166 to 192 ° C. It is preferable to have a temperature range of ° C. (most preferably 179 ° C.) so that injection molding is performed.

In addition to this, in the forming step of step S50 described above, after placing the high elasticity foam, shock absorbing foam, and support foam generated in the upper mold, the middle mold, and the lower mold at predetermined positions, a heat compression press is used to press 165 to 180 Press molding may be performed at a temperature of °C for 8 to 11 minutes (most preferably 580 seconds).

At this time, the above-described press molding may be performed in two tracks, firstly, after pressing the compound at a temperature of 100 to 120 ° C (most preferably 110 ° C) in each mold, and then secondarily using a press machine to 150 to 190 ° C ( Most preferably, the molded articles demolded from the upper mold, middle mold, and lower mold by thermal compression for 9 to 11 minutes (most preferably 10 minutes) using a temperature of 170 ° C.) under predetermined molding conditions. It can be foamed so that an integrally bonded foam is obtained.

Referring to FIG. 5 for a more detailed description of this, as an experimental example of this molding method, appearance test results according to molding time are attached to examine the crosslinking adhesive properties.

Specifically, in FIG. 7, it will be understood that white, yellow, and red colors correspond to high elasticity foam, shock absorbing foam, and support foam, respectively, and when the molding time is 6 to 8 minutes, the shock absorbing foam is the interface between the other foams. It was observed that the high elasticity foam, the shock absorbing foam, and the support foam were completely cross-linked without being separated from each other only after 10 minutes.

That is, through these experiments, it was confirmed that press molding for at least 10 minutes at a temperature of 165 to 180 ° C is required to manufacture a multi-function sole using an EVA blend.

In addition, in FIG. 4, it is possible to look at the formulation table for the support foam, high elasticity foam, and shock absorbing foam finally established based on the multi-injection molding method for manufacturing the multi-function sole. As a result, in the present invention, the conventional sole manufacturing process used It has the effect of providing a sole manufacturing technology that can simplify the process with a multi-injection process by replacing the complex remolding process, and at the same time solving the problem of interfacial adhesion between different materials to realize a variety of functionalities and designs. It has the effect of being able to provide.

In addition, the present invention does not require a complicated bonding process to manufacture a multi-function sole, thereby simplifying the process and reducing process costs. It can be expected to see the effect that can be reduced.

Meanwhile, in the following, as another embodiment of the present invention, a description of a multiple injection molding apparatus for manufacturing a multi-function sole will be continued.

Referring to 100 in FIG. 6 as a description thereof, 100 in FIG. 6 shows a schematic configuration diagram of a multi-injection molding apparatus for manufacturing a multi-function sole.

As shown in 100 of FIG. 6, in the present invention, a hopper 10, an injection machine 20, a mold 30, a press machine 40, and a controller 50 may be included as main components.

At this time, it can be understood that the above-described hopper 10 is a space for storing a mixture of a raw material including at least one of zinc oxide, stearic acid, and calcium carbonate in EVA resin obtained by polymerizing vinyl acetate monomer and ethylene monomer.

At this time, it is preferable to understand that the above-mentioned mixture is the same as the mixture examined in the above-mentioned multi-injection molding method for manufacturing a multi-function sole.

Meanwhile, the above-described injection molding machine 20 is provided with a heating cylinder 21 to supply the raw material mixture stored in the hopper 10 to the mold 30 in a plasticized state.

Specifically, it is preferable that the above-described heating cylinder 21 is provided with a screw to increase the convenience of conveying the mixture.

In addition, the above-described mold 30 may preferably include an upper mold 31 , a middle mold 32 , and a lower mold 33 .

At this time, the upper plate mold 31 described above corresponds to a mold for generating a highly elastic foam, the above-described middle plate mold 32 corresponds to a mold for generating a shock absorbing foam, and the above-described lower plate mold 33 corresponds to a support body It will be understood as a concept corresponding to a mold that creates a form. In the present invention, the middle plate mold 32 is provided with a structure inserted between the upper plate mold 31 and the lower plate mold 33, so that multiple injection At the same time, it is possible to realize complete interfacial bonding of molded products demolded from each mold in one press process.

As an example of this, referring to FIG. 7, a schematic form of the mold 30 of the present invention can be seen in A of FIG. 7, M1 is an upper mold, M2 is a lower mold, and M1 and M3 are It will be understood that the M3 with the inserted installation structure is a heavy plate mold.

On the other hand, a molded product injection-molded using an injection molding machine in a mold of the same shape as A in FIG. 7 can be seen in B in FIG. It will be understood that P3 is a demolded support foam, and P3 is a shock absorbing foam demolded from a middle plate mold.

Returning to FIG. 6 again, continuing the description of the multi-injection molding apparatus for manufacturing a multi-function sole, the above-described press machine 40 functions to thermally compress the molded articles released from the mold.

At this time, it will be understood that the press conditions mentioned in the molding step of the multi-injection molding method for manufacturing the multi-function sole are identically used for the thermal compression conditions of the press machine 40 described above. As the press machine 40 is provided, it is possible to obtain a foam body in which the high elasticity foam demolded from the injection machine 20, the shock absorbing foam, and the support foam are integrally combined.

Meanwhile, the above-described controller 50 functions to control the operation of components including at least one of the above-described hopper 10, mold, injection machine 20, and press machine 40.

More specifically, the above-described controller 50 is an operation control command for the hopper 10, and provides control commands including power control of the hopper 10 and control of the amount of the mixture supplied from the hopper 10 to the injection molding machine 20. It will be possible to transmit, and as a control command for the mold described above, a control command for opening and closing the mold can be transmitted.

In addition, the above-described controller 50 may control the temperature of the heating cylinder 21 provided in the injection molding machine 20. As an example, the controller 50 supplies the raw material mixture to the upper mold 31. The temperature is set at 166 to 192 ° C, the temperature is set at 104 to 140 ° C when the raw material mixture is supplied to the middle mold 32, and the temperature is set at 166 to 192 ° C when the raw material mixture is supplied to the lower mold 33 A temperature control function allowing a temperature of °C to be set may be performed.

At this time, it is preferable to understand that the above-described temperature control conditions are temperature control conditions for imparting functionality for high elasticity, shock absorption, and abrasion resistance to foam moldings produced in each mold.

In addition, the above-described controller 50 may transmit commands for power control of the press machine 40 and temperature and pressure control commands for the press machine 40 as control commands for the press machine 40 described above.

Similarly, the control conditions of the above-described press machine 40 may be a pressure of 30 to 100 kgf / cm ² at a temperature of 165 to 180 ° C used in the thermocompression molding step of the description of step S50 of FIG. 1 described above. There will be and the present invention is not limited thereto.

Meanwhile, in FIG. 8, a product picture of the multi-function sole obtained from the multi-injection molding method and apparatus for manufacturing the multi-function sole described above is attached.

Evaluating the appearance of the multi-function sole in these product photos, it was confirmed that the interfaces were completely adhered without separation, and that a smooth surface and sophisticated finish were achieved.

In addition, referring to FIG. 9, in FIG. 9, a test report for a multi-function sole product manufactured by the multiple injection molding method and apparatus for manufacturing a multi-function sole described above is attached.

Specifically, the test report attached to FIG. 9 is an official test report evaluated by the Korea Apparel Testing & Research Institute for the high elasticity foam (sample A1) and the support foam (sample A2). Looking at the test report for the high elasticity foam, specific gravity, hardness, As a result of the test with compression set and heat shrinkage as test items, the specific gravity was 0.17, the hardness was 32, the compression set was 12%, and the heat shrinkage was -0.5% in the longitudinal direction and 0.5% in the transverse direction. has been derived

Examining these test results in detail, it was found that the elongation rate was excellent due to the low specific gravity, but the hardness was 30 or more, showing sufficient mechanical strength in the highly elastic foam. It was greatly reduced to 12%, and the heat shrinkage was greatly reduced to 0.5% compared to the conventional heat shrinkage of 2 to 5% in the horizontal and vertical directions, indicating that the shape stability was greatly improved.

Next, looking at the test report for the support foam, the test was conducted with specific gravity, hardness, heat shrinkage and abrasion resistance as test items for the support foam, and as a result, the specific gravity was 0.25, the hardness was 60, and the compression set was 15. %, heat shrinkage was -0.5% in the transverse direction, -0.5% in the longitudinal direction, and the test results were derived that the abrasion resistance was 49.7%.

Judging from these test results, the support foam had a low specific gravity and excellent elongation, but the hardness was about twice as high as that of the high elasticity foam, indicating that the mechanical strength was reinforced.

In addition, it was found that the compression permanent shrinkage rate was 16% compared to the conventional 80% level, which greatly reduced, and the thermal shrinkage rate was also 0.5% compared to the conventional 2 to 5% thermal shrinkage in the horizontal and vertical directions. It was found that there was only a significant decrease.

In addition, even though the support foam was a foam, the abrasion resistance rate reached close to 50%, indicating that the foam properties, which were weak in abrasion resistance, were improved.

In other words, through this, in the present invention, various functions can be provided due to the multi-function sole manufacturing technology that dramatically simplifies the process steps by the multiple injection molding process without applying the complicated remolding process used in the conventional sole manufacturing process. It has been confirmed that mass production of multi-function sole products that can

As described above, the multi-injection molding method and apparatus for manufacturing the multi-function sole of the present invention have been described, but the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention Within the scope of the same concept, other embodiments may be easily proposed by adding, changing, deleting, or adding components, but this will also be said to fall within the scope of the present invention.

In addition, terms such as "include", "comprise" or "have" described above mean that the corresponding component may be inherent unless otherwise stated, excluding other components. It should be construed as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless defined otherwise. Commonly used terms, such as terms defined in a dictionary, should be interpreted as consistent with the meaning in the context of the related art, and unless explicitly defined in the present invention, they are not interpreted in an ideal or excessively formal meaning.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

Claims (10)

In the multi-injection molding method for manufacturing a multi-function sole,
Contains at least one of Zinc Oxide, Stearic Acid, and Calcium Carbonate in EVA resin polymerized with Vinyl Acetate Monomer (VAM) and Ethylene Monomer Raw material mixing step of mixing the raw materials to;
adding an additive containing at least one of a foaming agent and a crosslinking agent to the mixture obtained by performing the raw material mixing step to control the physical properties of the multi-function sole;
A processing step of processing the composition obtained after performing the additive input step by a processing method including at least one of pellet processing and rolling processing; and,
A molding step of molding the processed composition by injecting it into a prepared mold using an injection molding machine; including,
The molding step is
Multi-injection molding method for manufacturing a multi-function sole, characterized in that by using the composition, the molded products demolded from the upper mold, the middle mold, and the lower mold are foamed under predetermined molding conditions to obtain an integrally combined foam.
According to claim 1,
The molding step is
Using the composition, a high elasticity foam is produced in the upper mold, a shock absorbing foam is formed in the middle mold, and a support foam is formed in the lower mold,
In the high elasticity foam, silicone rubber is further added to the composition,
The multi-injection molding method for manufacturing a multi-function sole, characterized in that to further add active zinc oxide to the shock-absorbing foam to the composition.
According to claim 2,
When performing the molding step,
Different molding temperatures are set for the upper plate mold, the middle plate mold, and the lower plate mold,
The molding temperature of the high elasticity foam is 166 to 192 ° C, the molding temperature of the shock absorbing foam is 104 to 140 ° C, and the molding temperature of the support foam is 166 to 192 ° C. Multi-function sole, characterized in that Multiple injection molding methods for fabrication.
According to claim 2,
The molding step is
After disposing the high elasticity foam, shock absorbing foam, and support foam generated from the upper mold, the middle mold, and the lower mold at predetermined positions, they are pressed at a temperature of 165 to 180° C. for 8 to 11 minutes using a thermocompression press. Multiple injection molding method for manufacturing a multi-function sole, characterized by molding.
According to claim 1,
In the processing step,
A multi-injection molding method for manufacturing a multi-function sole, characterized in that the composition is subjected to processing including at least one of pellet processing and rolling processing having a thickness of 10 mm to 24 mm.
According to claim 1,
In the step of adding the additive,
A JTR foaming agent containing at least azobisformamide is used as the foaming agent,
A multi-injection molding method for manufacturing a multi-function sole, characterized in that using a peroxide cross-linking agent containing at least dicumyl peroxide (DCP) as the cross-linking agent.
According to claim 1,
The raw material mixing step,
In the EVA resin, using a vinyl acetate (VA, Vinyl Acetate) content of 9.3 to 28.0% by weight,
3 to 7 parts by weight of the zinc oxide, 0.5 to 2 parts by weight of the stearic acid, and 7 to 12 parts by weight of the calcium carbonate per 100 parts by weight of the EVA resin. injection molding method.
In the multiple injection molding device for manufacturing a multi-function sole,
A hopper in which a mixture of a raw material including at least one of zinc oxide, stearic acid, and calcium carbonate in an EVA resin obtained by polymerizing vinyl acetate monomer and ethylene monomer is stored;
a mold provided as an upper plate mold, a middle plate mold, and a lower plate mold;
an injection machine equipped with a heating cylinder to supply the raw material mixture stored in the hopper to the mold in a plasticized state;
a press machine for thermally compressing the moldings demolded from the mold; and,
A multi-injection molding apparatus for manufacturing a multi-function sole, characterized in that it includes; a controller for controlling the operation of components including at least one of the hopper, the mold, the injection machine, and the press machine.
According to claim 8,
The mold,
The multi-injection molding apparatus for manufacturing a multi-function sole, characterized in that the middle plate mold is provided in a structure inserted and installed between the upper plate mold and the lower plate mold.
According to claim 8,
The heating cylinder is variably controlled in heating temperature according to the mold to which the raw material mixture is supplied,
When the raw material mixture is supplied to the upper plate mold, a temperature of 166 to 192 ° C is set,
When the raw material mixture is supplied to the middle plate mold, a temperature of 104 to 140 ° C is set,
When the raw material mixture is supplied to the lower mold, a multi-injection molding apparatus for manufacturing a multi-function sole, characterized in that a temperature of 166 to 192 ° C is set.

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