Composite of adhesive films and shoe sole using same

Abstract

Disclosed therein are adhesive films and a composite of the adhesive film, which can allow an outsole and a midsole to be simultaneously molded in manufacturing footwear. The adhesive film composite is formed of a polyester-type thermoplastic polyurethane (TPU) material, a polyethylene-based coupling agent, montan wax and fatty acid esters with pentaerythritol.

Claims

1. An adhesive film composite comprising: a polyester-type thermoplastic polyurethane (TPU) material; 2 to 50 percent by weight of a polyethylene-based coupling agent comprising 6 to 20 percent of maleic anhydride; 0.2 parts by weight of montan wax; and 2 parts by weight of fatty acid esters with pentaerythritol, the fatty acid having five to nine carbons, where all parts by weight are relative to 100 total parts by weight of polyester-type TPU material and polyethylene-based coupling agent.

2. The adhesive film composite of claim 1, comprising 50 to 98 percent by weight of polyester-type TPU.

3. The adhesive film composite of claim 1, wherein the polyethylene-based coupling agent is a EVA-based compatibilizer.

4. The adhesive film composite of claim 1, wherein the composite comprises 77.5 percent by weight of the polyester-type TPU material and 22.5 percent of the polyethylene-based coupling agent, in which the polyethylene-based coupling agent is EVA-based compatibilizer containing 6 percent of maleic anhydride.

5. A shoe sole comprising: a first sole formed of rubber; a second sole formed of an ethylene vinyl acetate (EVA) foam; a first adhesive film interposed between the first sole and a first surface of the second sole; and a second adhesive film disposed on a second surface of the second sole, wherein the second adhesive film comprises: a polyester-type thermoplastic polyurethane (TPU) material; 2 to 50 percent by weight of a polyethylene-based coupling agent containing maleic anhydride; 0.2 parts by weight of montan wax; and 2 parts by weight of fatty acid esters with pentaerythritol, the fatty acid having five to nine carbons, where all parts by weight are relative to 100 total parts by weight of polyester-type TPU material and polyethylene-based coupling agent.

6. The shoe sole of claim 5, wherein the second adhesive film comprises 50 to 98 percent by weight of polyester-type TPU.

7. The shoe sole of claim 5, wherein the first adhesive film comprises: a thermoplastic elastomer; polyethylene-based coupling agent; a montan wax; and fatty acid esters with pentaerythritol.

8. The shoe sole of claim 7, wherein the thermoplastic elastomer of the first adhesive film comprises 50 to 98 percent by weight of syndiotactic 1,2-polybutadiene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a view showing a method of manufacturing footwear using adhesive films according to a preferred embodiment of the present invention;

(3) FIG. 2 is a view showing a method of molding an outsole shown in FIG. 1;

(4) FIG. 3 is a view showing the outsole molded by the method of FIG. 2;

(5) FIG. 4 is a view showing how to simultaneously mold the outsole and a midsole shown in FIG. 1;

(6) FIG. 5 is a view showing a shoe sole on which the outsole and the midsole are simultaneously molded by the method of FIG. 4;

(7) FIG. 6 is a graph showing a differential thermal analysis of first adhesive films shown in FIG. 1;

(8) FIG. 7 is a graph showing a differential thermal analysis of a second adhesive film shown in FIG. 2; and

(9) FIG. 8 is a view showing a method of manufacturing footwear including an outsole, a midsole and an upper according to a prior art.

DETAILED DESCRIPTION OF THE INVENTION

(10) Reference will be now made in detail to the preferred embodiment of the present invention with reference to the attached drawings. The representative embodiment will be written in the following detailed description to achieve the above-stated objects. Moreover, the description will be substituted for other embodiments, which may be proposed in the present invention.

(11) The present invention is to realize a method of manufacturing footwear using adhesive films and a composite of the adhesive film, which can allow an outsole and a midsole to be simultaneously molded and formed through the steps of putting the midsole made of EVA foam and the outsole made of rubber into a mold, inserting an adhesive film between the midsole and the outsole, and applying high temperature and high pressure to the midsole and the outsole, thereby not needing to carry out a cleaning process, a primer coating process, and a bonding process when an outsole and a midsole are manufactured, not needing additional facilities for the cleaning and bonding processes, reducing unnecessary manpower, and improving working environments.

(12) For this, a method of simultaneously forming the midsole and the outsole should be disclosed in detail, and composite of the adhesive film used when the midsole and the outsole are simultaneously formed should be described in detail.

(13) Hereinafter, referring to the drawings, the preferred embodiment of the present invention will be described in detail.

(14) FIGS. 1 to 5 are detailed views showing the method of simultaneously forming and manufacturing footwear, which includes an outsole, a midsole, and an upper, using adhesive films according to a preferred embodiment of the present invention.

(15) A method of molding a shoe sole 700 having an outsole 300 and a midsole 500 simultaneously molded includes the steps of: inserting a first adhesive film 200 and a rubber sheet 100 into a mold 10, which is generally used for molding outsoles, applying high temperature and high pressure to the mold to mold an outsole 300, inserting the molded outsole 300 with the first adhesive film 200 into a phylon mold 20, which is generally used for molding midsoles; putting a first adhesive film 400, an EVA foam 500a, and a second adhesive film 600 in order; and molding them at high temperature and high pressure. That is, the outsole 300 and the midsole 500 are bonded by the first adhesive films 200 and 400 inside the phylon mold 20, and the shoe sole 700 formed by bonding of the outsole 300 and the midsole 500 and the upper are bonded by the second adhesive film 600. In this instance, when the shoe sole 700 and the upper are bonded together, the first adhesive films 200 and 400 in lieu of the second adhesive film 600 may be used.

(16) Referring to FIGS. 1 and 2, the outsole 300 shown in FIG. 3 is molded through the steps of inserting unvulcanized rubber into the mold 10 for outsoles, putting the first adhesive film 200 on the unvulcanized rubber, and vulcanizing them at high temperature and high pressure (preferably, at temperature of 150 C. to 160 C. and at pressure ranging from 100 kgf/cm.sup.2 to 160 kgf/cm.sup.2) for five to ten minutes. When the outsole 300 is molded as described above, if the first adhesive film 200 is used, there is no need to carry out the processes required to bond the outsole and the midsole, in detail, buffing, cleaning, primer coating, and bonding processes. The composite and properties of the first adhesive film 200 will be described later in detail.

(17) Next, as shown in FIG. 4, the outsole 300 on which the first adhesive film 200 is molded integrally is inserted into the phylon mold 20, the first adhesive film 400 is put on the outsole 300, the EVA foam 500a is put on the first adhesive film 400, and then, the second adhesive film 600 is put on the EVA foam 500a. In this instance, the EVA foam 500a means the EVA foam foamed by a general method, for instance, an EVA of a biscuit form is foamed and molded about 190 percent larger than the actual size of the midsole. Moreover, the phylon mold 20 is a generally used mold, namely, means a mold generally used when midsoles are manufactured. It is preferable that the phylon mold 20 used in the present invention is deeper than the conventional phylon mold. The reason is to insert all of the outsole 300, the first adhesive film 400, the EVA foam 500a, and the second adhesive film 600 into the phylon mold 20 at once.

(18) After that, as shown in FIG. 4, when the outsole 300, the first adhesive film 400, the EVA foam 500a, and the second adhesive film 600 inserted into the phylon mold 20 are pressurized at temperature of 160 C. and at pressure of 60 kgf/cm.sup.2, the shoe sole 700 that the outsole 300 and the midsole 500 are molded simultaneously as shown in FIG. 5 is manufactured.

(19) Finally, when the shoe sole (preferably, shoe sole that the outsole and the midsole are simultaneously molded in the phylon mold) manufactured through the above molding method and the upper (not shown) manufactured through a general method are bonded together, the footwear according to the present invention is manufactured. In this instance, the shoe sole 700, in detail, the midsole 500, and the upper are bonded by the second adhesive film 600.

(20) In the meantime, as described above, the adhesive films are used in order to simultaneously pressurize and mold the outsole 300 and the midsole 500 inserted into the phylon mold, and in detail, the first adhesive films 200 and 400 are used to bond the outsole 300 and the EVA-foamed midsole 500, and the second adhesive film 600 is used to bond the midsole 500 and the upper. Hereinafter, composites and properties of the first and second adhesive films 200, 400 and 600 will be described in detail.

(21) First, as shown in FIG. 4, the first adhesive films 200 and 400, used when the outsole 300 and the midsole 500 are simultaneously bonded and molded in the phylon mold 20, contain rubber-based thermo plastic elastomer (hereinafter, called TPE) or olefin series material or rubber series material as the main ingredient for rubber bonding, preferably, 50 to 98 percent by weight of syndiotactic 1,2-polybutadiene. In this instance, if syndiotactic 1,2-polybutadiene which is less than 50 percent by weight is used, linearity and intensity of the films are decreased, and if syndiotactic 1,2-polybutadiene which is more than 98 percent by weight is used, the adhesive force is deteriorated.

(22) Furthermore, the first adhesive films 200 and 400 contain polyethylene-based coupling agent or ethylene vinyl acetate (hereinafter, called EVA)-based coupling agent as the main ingredient for EVA foam bonding, preferably, 2 to 50 percent by weight of polyethylene-based coupling agent, which contains 2 to 20 percent of maleic anhydride. In this instance, if the polyethylene-based coupling agent which is less than 2 percent by weight is used, the adhesive force is deteriorated, and if the polyethylene-based coupling agent which is more than 50 percent by weight is used, linearity and intensity of the films are decreased.

(23) Moreover, in the present invention, processing materials for 100 parts by weight of the main ingredients are additionally used. In detail, 0.2 parts by weight of montan wax and 2 parts by weight of fatty acid (C=5-9) esters with pentaerythritol having five to nine carbons are used. In this instance, the processing materials are used to make the first adhesive films 200 and 300 smoothly get out of a T-die without being attached to a dies lip when they are extruded in the T-die.

(24) The following Table 1 shows a detailed composition ratio of the first adhesive films 200 and 400.

(25) TABLE-US-00001 TABLE 1 Composite of 1.sup.st adhesive film Composition Ratio Remark Syndiotactic 1,2- 95% by weight polybutadiene Polyethylene-based coupling 5% by weight agent (containing 7 percent of maleic anhydride) Montan wax 0.2 pbw part by weight Esters with Pentaerythritol 2 pbw part by weight

(26) The following Table 2 shows test data values obtained through comparison and analysis of properties of the first adhesive films 200 and 400 and properties of the ingredient materials.

(27) TABLE-US-00002 TABLE 2 First adhesive Syndiotactic Polyethylene- Film of the 1,2- based coupling Present Test Method Specification polybutadiene agent invention Type FT-IR TPE PE Base (Rubber Base) Containing MA Melt Temperature DSC 96.11 C. 111.7 C. 116.35 C. Flow Beginning Capillary 105.9 C. 108.9 C. 106.6 C. Temperature Rheo-meter Specific Gravity 0.943 g/cc 100% Modulus UTM 78 kgf/cm.sup.2 Tensile strength UTM 175 kgf/cm.sup.2 Tear Strength UTM 78 kgf/cm Elongation UTM 500%

(28) In addition, FIG. 6 shows a differential thermal analysis of the first adhesive films 200 and 400 having the properties shown in Table 2. The graph of FIG. 6 shows melt temperatures and heat flows of the first adhesive films 200 and 400, and for this, a DSC (Differential Scanning calorimetry) is used.

(29) Meanwhile, as shown in FIG. 4, when the outsole 300 and the midsole 500 are simultaneously molded in the phylon mold 20, the second adhesive film 600 put on the EVA foam 500a contains 50 to 98 percent by weight of polyester-type TPU as the main ingredient for bonding with the upper (for instance, made of textile, synthetic leather, or natural leather) and 2 to 50 percent by weight of EVA-based compatibilizer (containing 2 to 20 percent of maleic anhydride, preferably, 6 percent of maleic anhydride) as the main ingredient for EVA foam bonding. In this instance, if polyester-type TPU which is less than 50 percent by weight is used, the bond strength is deteriorated, and if polyester-type TPU which is more than 98 percent by weight is used, compatibility with an adherend and wetting mechanism are decreased, and hence, the adhesive film 600 is not adhered. Moreover, if EVA-based compatibilizer which is less than 2 percent by weight is used, compatibility with the adherend and wetting mechanism are decreased, and hence, the adhesive film 600 is not adhered. If EVA-based compatibilizer which is more than 50 percent by weight is used, bond strength is deteriorated.

(30) In addition, in the present invention, processing materials for 100 parts by weight of the main ingredients are additionally used. In detail, 0.2 parts by weight of montan wax and 2 parts by weight of fatty acid (C=5-9) esters with pentaerythritol having five to nine carbons are used. In this instance, the processing materials are used to make the second adhesive film 600 smoothly get out of a T-die without being attached to a dies lip when they are extruded in the T-die.

(31) The following Table 3 shows a detailed composition ratio of the second adhesive film 600.

(32) TABLE-US-00003 TABLE 3 Composite of 2.sup.nd adhesive film Composition Ratio Remark Polyester type TPU 77.5% by weight EVA-based compatibilizer 22.5% by weight (containing 6 percent of maleic anhydride) Montan wax 0.2 pbw part by weight Esters with Pentaerythritol 2 pbw part by weight

(33) Additionally, the following Table 4 shows the properties of the second adhesive film 600 in detail.

(34) TABLE-US-00004 TABLE 4 Second adhesive Test Method Specification film Melt Temperature DSC 102.35 C. 158.15 C. Flow Beginning Capillary Rheo-meter 155.2 C. Temperature Specific Gravity 1.141 g/cc Thickness Thickness Gauge 0.11 mm 300% Modulus UTM 130 kgf/cm.sup.2 Tensile strength UTM 610 kgf/cm.sup.2 Tear Strength UTM 107 kgf/cm UTM 560%

(35) Moreover, FIG. 7 shows a differential thermal analysis of the second adhesive film 600 having the properties shown in Table 4. The graph of FIG. 7 shows melt temperatures and heat flows of the second adhesive film 600, and for this, a DSC (Differential Scanning calorimetry) is used.

(36) As described above, the adhesive films of the present invention are divided into the second adhesive film 600 for bonding the midsole made of EVA foam and the upper with each other and the first adhesive films 200 and 400 for bonding the outsole and the midsole made of EVA foam, and through the adhesive films, as shown in FIG. 4, the outsole 300 and the EVA foam midsole 500a are simultaneously molded in the phylon mold 20, and finally, the shoe sole 700 having the outsole 300 and the midsole 500 simultaneously bonded and molded in one mold (phylon mold) as shown in FIG. 5 is manufactured. Finally, the upper is simply bonded to the midsole 500 by the second adhesive film 600 adhered on the midsole 500, so that the footwear according to the present invention is completely manufactured.