KR20210004368A - Composition for treating midsole surface for improving bonding property, midsole surface-treating member, and manufacturing method of multi-layers midsole using the same - Google Patents

Abstract

The present invention relates to a composition for treating a surface of a midsole to improve adhesion performance, a member for treating a surface of a midsole, and a method of manufacturing a multilayer midsole by using the same, and more particularly, to a composition for treating a surface of a midsole, which is a composition for improving adhesion performance between a midsole and at least one selected from the group consisting of a shoe leather upper, an insole, and an outsole, the composition including: an ethylene-vinylacetate copolymer, a crosslinking agent, and a foaming agent. According to the composition for treating the surface of the midsole of the present invention, the adhesion performance of the midsole is improved to ensure diversity of a midsole material, so that midsoles having various physical properties are manufactured.

Description

Composition for surface treatment of midsoles to improve adhesion performance, surface treatment members for midsoles, and a method of manufacturing multi-layer midsoles using the same. }

The present invention relates to a composition for surface treatment of a midsole for improving adhesion performance, a surface treatment member for a midsole, and a method for manufacturing a multilayer midsole using the same.

Shoes are largely composed of an upper, an insole, a midsole, and an outsole, and these parts are mainly manufactured into shoes by assembling them using adhesives. The upper is the largest area of the shoe that protects the foot by surrounding the back and sides of the foot, and is the part that has the greatest influence on the overall design of the shoe. The in-sole is called the insole or insole, and it relieves shock, supports the foot, and absorbs sweat and moisture. An out-sole is an outsole that comes into contact with the ground, and is called an outsole or sole. The outsole satisfies abrasion resistance, slip resistance, oil resistance, etc. in terms of functionality, and is manufactured with various rubber types and compounding additives in consideration of transparency and color change depending on temperature in terms of external appearance.

The mid-sole is the part between the insole and the outsole and is called a midsole. The midsole absorbs external shocks and can exhibit resilience, and is mainly made of foam to reduce the overall weight of the shoe. Various polymers such as ethylene-vinyl acetate (EVA), polypropylene (PP), polyethylene (PE), polystyrene (PS), and polyurethane (PU) are used in polymer foam, among which ethylene-vinyl acetate Foam is mainly used for midsoles.

The ethylene-vinyl acetate foam material requires a variety of physical properties, and among them, low density and high resilience are important. However, since density is inversely proportional to mechanical properties, it is necessary to find an optimal method with low density and less loss of mechanical properties. In addition, in general, since a polymer material having a low polarity has a low secondary bonding force, adhesion with other materials is very low, and problems such as poor adhesion are likely to occur in footwear products using such materials.

Currently, to secure the adhesive performance of the midsole, ethylene-vinyl acetate copolymer is mainly used as a midsole material of 70% by weight or more, but it is difficult to secure various physical properties due to the application of a limited material, and there is a limitation in terms of weight reduction. There is a need for a solution.

Korean Patent Registration No. 10-0828908 (registered on May 2nd, 2008)

In order to solve the above problems, the present invention provides a midsole surface treatment composition and a midsole surface treatment member for improving adhesion performance.

In addition, the present invention provides a method for manufacturing a multilayer midsole with improved adhesion performance using the composition or the member, and a multilayer midsole manufactured by the method.

The composition for treating the surface of the midsole according to the present invention is to improve the adhesion performance between the mid-sole and at least one selected from the group consisting of shoe upper, in-sole, and out-sole. As a composition for, the composition includes an ethylene-vinylacetate copolymer, a crosslinking agent and a foaming agent, and the ethylene vinyl acetate copolymer has a vinyl acetate (Va) content of 15 to 100 parts by weight. It may be 40 parts by weight.

The midsole surface treatment member according to the present invention may include the midsole surface treatment composition.

In the multilayer midsole according to the present invention, one or more of the midsole surface treatment members may be stacked on or under the midsole.

The method for manufacturing a multilayer midsole according to the present invention comprises the steps of preparing a surface treatment member and a midsole; Laminating the midsole surface treatment member and the midsole; Injecting the laminated midsole surface treatment member and the midsole into a midsole preform manufacturing mold and crosslinking foam to prepare a midsole preform; And molding the prepared midsole preform in a final mold.

The multilayer midsole according to the present invention may be prepared by the method of manufacturing the multilayer midsole.

In the case of the conventional midsole, the selection of the midsole material was limited due to the problem of adhesion performance, but the midsole surface treatment composition and the midsole surface treatment member including the composition according to the present invention can further improve the adhesive performance of the midsole material. Diversity can be secured.

As various materials can be used as midsole materials by the composition according to the present invention, a midsole having various physical properties such as high elasticity, high impact absorption, and ultra-low specific gravity can be used.

In addition, according to the method of manufacturing a multilayer midsole according to the present invention, a midsole of various materials may be integrated with the midsole surface treatment member to conveniently manufacture a midsole having improved adhesion.

1 is a flowchart schematically showing a method of manufacturing a multilayer midsole according to the present invention.

Hereinafter, the present invention will be described in detail.

The present invention provides a composition for surface treatment of a midsole for improving adhesion performance.

In the present invention, the term "mid-sole" is a part that is located between the in-sole and the out-sole inside the shoe and requires cushioning and shock absorption, and the term "mid-sole" and Can be used interchangeably. The midsole may have various forms, for example, a sheet, a sponge, or a foam, but is not limited thereto.

In the present invention, the term "composition for treating the surface of the midsole" refers to the adhesion performance between the mid-sole and at least one selected from the group consisting of shoe upper, in-sole and out-sole. It means a composition for improving.

The composition for treating the surface of the midsole according to the present invention may include an ethylene-vinylacetate copolymer, a crosslinking agent, and a foaming agent.

The ethylene vinyl acetate copolymer may be a thermoplastic elastomer produced by copolymerizing an ethylene monomer and a vinyl acetate monomer, and preferably an ethylene vinyl acetate copolymer having a melting point of 40 to 100°C. The melting point is a value measured by differential scanning calorimetry (DSC), and if the ethylene vinyl acetate copolymer having a melting point in the above range is included, it is advantageous in terms of processability, and it is possible to prevent shrinkage and deformation due to external environmental changes. I can.

The ethylene vinyl acetate copolymer may have a vinyl acetate (VA) content of 15 to 40 parts by weight based on the total 100 parts by weight, but is not limited thereto. Physical properties of the ethylene vinyl acetate copolymer may vary depending on the vinyl acetate (VA) content. For example, as the content of the vinyl acetate increases, the degree of crystallinity decreases, becomes flexible, and has rubber elasticity, resulting in improved elongation. In addition, it is excellent in workability and impact strength. According to an embodiment of the present invention, it was found that the higher the vinyl acetate content, the better the adhesive strength by the composition.

The composition may further include an ethylene-α-olefin copolymer, the ethylene vinyl acetate copolymer and the ethylene alpha olefin copolymer may be blended, preferably the ethylene vinyl acetate copolymer The weight ratio of the ethylene alpha olefin copolymer may be 9.9:0.1 to 8:2. The ethylene alpha olefin copolymer may be a random or block copolymer, preferably an ethylene-butene copolymer or an ethylene-octene copolymer. According to an embodiment of the present invention, the composition blended in the above range showed excellent adhesive strength, whereas when only the ethylene alpha olefin copolymer was used, low adhesive performance was exhibited.

The crosslinking agent may be selected from the group consisting of dicumyl peroxide, dibenzoyl peroxide, and di-tery-butyl peroxide, and the 1 minute half-life temperature is 160 to It may be 180° C., but is not limited thereto.

The blowing agent may include azodicarbonamide or modified azodicarbonamide, and the decomposition temperature thereof may be 170 to 210° C., but is not limited thereto.

The composition for treating the surface of the midsole according to the present invention may further include other additives, wherein the other additives are zinc oxide (ZnO) as a foaming aid, triallylcyanurate as a crosslinking aid, trimethylol, or Propanetrimethacrylate and stearic acid as an activator may be included, but the present invention is not limited thereto.

The present invention provides a midsole surface treatment member comprising the composition for midsole surface treatment. The midsole surface treatment member is a member for improving adhesion performance between the midsole and at least one selected from the group consisting of a shoe upper, an insole, and an outsole, and the midsole surface treatment member may be in the form of a sheet, film, or gel, but is limited thereto. It does not become. The midsole surface treatment member may be disposed above or below the midsole.

The present invention provides a multilayer midsole in which one or more midsole surface treatment members are stacked on or under the midsole. Specifically, it may be a three-layer midsole stacked on both the upper and lower surfaces of the midsole. Various materials may be used for the midsole, and adhesion between the midsole and its adjacent members, that is, a shoe upper, an insole, or an outsole may be improved by the midsole surface treatment member.

The present invention provides a method of manufacturing a multilayer midsole with improved adhesion performance.

1 is a flowchart schematically showing a method of manufacturing a multilayer midsole according to the present invention.

Referring to FIG. 1, the multilayer midsole manufacturing method includes preparing a midsole surface treatment member and a midsole (S10), laminating the midsole surface treatment member and the midsole (S20), the stacked midsole surface treatment member, and Injecting the midsole into a midsole preform manufacturing mold and crosslinking foaming to produce a midsole preform (S30), and molding the manufactured midsole preform in a final mold (S40).

In the method for manufacturing a multi-layer midsole according to the present invention, in the midsole surface treatment member and the midsole preparation step (S10), a midsole surface treatment member prepared with a composition for midsole surface treatment for improving adhesion performance, for example, is manufactured in a sheet form. You can prepare a midsole surface sheet. At this time, the midsole surface treatment member may be prepared in consideration of the balance with the midsole such as expansion ratio, crosslinking degree, and shrinkage ratio.If the expansion ratio of the midsole surface treatment member is greater than the expansion ratio of the midsole, interfacial peeling phenomenon after preparation of the preform Appears, and convex upward bending may occur. In the opposite case, the interface peeling phenomenon is the same, and in this case, a downward bending phenomenon may occur.

In the lamination step (S20), the prepared midsole surface treatment member and the midsole may be stacked, and in more detail, the midsole surface treatment member may be stacked on or under the midsole. For example, the midsole upper and The midsole surface treatment member may be stacked on both of the lower portions to form three layers. Preferably, the midsole and the midsole surface treatment member may be laminated at a thickness ratio of 95:5 to 90:10. At this time, in order to minimize empty spaces that may occur during lamination, a sheet forming machine may be used to make the thickness constant and increase the surface smoothness.

In the preform manufacturing step (S30), the stacked midsole surface treatment member and the midsole are introduced into a midsole preform manufacturing mold, and crosslinked foaming is performed to prepare an integrated multilayer midsole preform, for example, a three-layer integrated midsole preform. . The laminated midsole surface treatment member and midsole may be introduced into a midsole preform manufacturing mold and crosslinked foaming for 6 to 12 minutes at a temperature of 150 to 180°C and a pressure of 130 to 160 kgf/cm ² . In this case, the foaming ratio may be 150 to 200%, and the initial foaming rate after foaming and the foaming rate after cooling may be the same in order to prepare a normal form of preform. According to an embodiment of the present invention, it was prepared by crosslinking foaming under conditions of 10 minutes at a temperature of 155°C and a pressure of 150kgf/cm ² .

In the midsole preform forming step (S40), the prepared midsole preform may be heated in a final mold at a temperature of 140 to 160° C. for 5 to 7 minutes, and then cooled to room temperature to be molded. According to an embodiment of the present invention, after heating for 5 minutes at a temperature of 150 ℃ cooled and withdrawn.

The method for manufacturing a multilayer midsole according to the present invention may further include the step of cutting and finishing the formed midsole (S50).

In addition, the present invention provides a multilayer midsole manufactured by the above manufacturing method.

The multilayer midsole may have an adhesive strength with at least one selected from the group consisting of a shoe upper, an insole and an outsole of 3.0 to 4.0 kgf/cm, and an adhesive strength between the midsole surface treatment member and the midsole of 2.5 to 3.0 kgf/ can be cm According to an embodiment of the present invention, the adhesive strength between the three-layer midsole and the outsole was measured as 3.0 to 3.5 kgf/cm, and the midsole surface treatment member, that is, the midsole surface sheet and the midsole, that is, the co-crosslinking between the midsole sheet The adhesive strength by was measured as 2.5 to 3.0 kgf / cm.

Hereinafter, examples will be described in detail to aid understanding of the present invention. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited to the following examples. The embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art.

<Example 1> Preparation of a midsole surface treatment member (midsole surface sheet) and midsole (midsole sheet) with improved adhesion performance

1. Raw materials used

1) VS410 (Lotte chemical)-Ethylene Vinyl Acetate Copolymer (EVA Copolymer), Vinyl Acetate (Va) Content: 26% by weight (wt%), melt index; or less , MI): 4.0 g/10 min.

2) VS420 (Lotte chemical)-Ethylene vinyl acetate copolymer, VA content: 21.5% by weight, melt index: 2.0 g/10 min.

3) VC590 (Lotte chemical)-Ethylene vinyl acetate copolymer, VA content: 28% by weight, melt index: 4.0 g/10 min.

4) VC710 (Lotte chemical)-Ethylene vinyl acetate copolymer, VA content: 33% by weight, melt index: 20.0 g/10 min.

5) DF810 (Mitsui chemical)-Ethylene-α-Olefin Copolymer, Melt Index: 1.2 g/10 min.

2. Midsole surface treatment member (midsole surface sheet) production

Ethylene vinyl acetate copolymer (EVA Copolymer) 80-100 parts by weight, stearic acid 1 part by weight, zinc oxide 2 parts by weight, crosslinking agent (BIPB; bis(t-butylperoxyisopropyl)benzene) [bis(t-butylperoxyisopropyl)benzene]) 0.6 to 1.2 parts by weight and 4 to 7 parts by weight of a blowing agent (JTR) are sequentially added to a kneader, which is a closed-type kneader, and mixed, and the open mill is an open-type kneader. After performing the kneading in the sheet was formed. After being allowed to stand at room temperature, melt-molding in a press using a 0.5mm-thick space bar, followed by cooling, to produce a midsole surface sheet with a thickness of 0.5mm and a smooth surface.

The main composition was as shown in Tables 1 and 2 of the evaluation of midsole properties to be described later, and the composition of other materials was the same.

3. Midsole (midsole sheet) production

100 parts by weight of ethylene-α-olefin copolymer, 1 part by weight of stearic acid, 2 parts by weight of zinc oxide, 1.0 parts by weight of crosslinking agent (BIPB) and 6 parts by weight of blowing agent (JTR) It was sequentially added to a kneader and mixed, and then kneaded in an open mill, an open kneader, and then sheeted. After being allowed to stand at room temperature, melt-molding in a press using a space bar of 10 mm thick and then cooled to produce a midsole sheet having a smooth surface having a thickness of 10 mm.

4. Sheet lamination and 3-layer midsole preform manufacturing

After laminating the midsole surface sheet on and below the midsole sheet, it was put into a preform manufacturing mold, and crosslinked foaming was performed under conditions of a temperature of 155°C, a pressure of 150 kgf/cm 2, and a time of 10 minutes. The sheet stack is the same as the inner shape of the preform manufacturing mold, and it is preferable to maintain 95% or more of the inner volume of the mold for ease of input and maintenance of the shape.

5. Forming the 3-layer midsole preform in the final mold

A three-layer midsole preform was put into a final molding mold, heated at 150° C. for 5 minutes, cooled to room temperature in a cooling press, and molded and taken out.

<Example 2> Midsole property evaluation

The completed midsole (three-layer midsole) was subjected to an adhesion test according to the following test methods and test items, and the physical property results were confirmed.

1. Manufacture of adhesive specimen

The standard crosslinked outsole specimen was washed, puffed, primer applied and dried, adhesive applied and dried, and the resulting final three-layer midsole specimen was washed, UV primer treated and irradiated, primer applied and dried, adhesive applied, and dried. An adhesive specimen was prepared by pressing.

2. Adhesion strength between outsole and 3-layer midsole

The adhesive specimen prepared in No. 1 was subjected to a 180° peel test by attaching an outsole crosslinked specimen to the upper clamp of the tensile tester and a 3-layer midsole to the lower clamp.

3. Adhesive strength between the midsole surface sheet and the midsole sheet

A 180° peel test was performed by attaching the midsole surface sheet to the upper clamp of the tensile tester and the midsole sheet to the lower clamp using the prepared final three-layer midsole.

Table 1 shows the composition of the midsole surface sheet prepared according to Example 1 and the adhesive strength between the outsole and the three-layer midsole, and the midsole surface sheet and the midsole sheet according to the composition.

Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 3 Manufacturing Example 4 Manufacturing Example 5 Comparative Example 1 VS410 100 VS420 100 VS590 100 80 VS710 100 DF810 20 100 Outsole-midsole adhesive strength
(kgf/cm)
3.1
3.2
3.5
3.2
3.1
0.8 Surface sheet-
Midsole Seat
Adhesive strength
(kgf/cm)

2.9

2.8

2.7

2.7

2.7

3.6

Referring to Table 1, it was found that the adhesive strength between the three-layer midsole and the outsole of Preparation Example 3 using an ethylene vinyl acetate copolymer having a high VA content and a low MI as a substrate was the best. On the other hand, in the case of Comparative Example 1 using the ethylene-alpha-olefin copolymer as a substrate, it was confirmed that no adhesion between the three-layer midsole and the outsole was achieved.

Manufacturing Example 6 Manufacturing Example 7 Manufacturing Example 8 Comparative Example 2 Comparative Example 3 Comparative Example 4 VS590 100 100 100 100 100 100 blowing agent 5 6 6 3 6 6 Crosslinking agent One One 0.9 One 0.5 1.3 Outsole-midsole adhesive strength
(kgf/cm)
3.3
3.4
3.3
3.1
3.1
3.2 Surface sheet-
Midsole Seat
Adhesive strength
(kgf/cm)

2.9

2.8

2.8

2.1

2.2

2.1

Table 2 shows the adhesion strength between the outsole and the three-layer midsole and the midsole surface sheet and the midsole sheet according to the VS590, which has the highest adhesive strength between the outsole and the three-layer midsole in Table 1, and the amount of the foaming agent and crosslinking agent.

Referring to Table 2, in the case of Comparative Example 2 having a small amount of the foaming agent, it was found that co-crosslinking was not smoothly performed due to different crosslinking densities and foaming ratios between the midsole surface sheet and the midsole sheet, and thus adhesion properties were reduced. In addition, in the case of Comparative Examples 3 and 4 having a low or high crosslinking agent amount, co-crosslinking was not smoothly performed due to different crosslinking densities and foaming ratios between the midsole surface sheet and the midsole sheet, indicating that the adhesive properties decreased.

As described above, specific parts of the present invention have been described in detail, and for those of ordinary skill in the art, it is obvious that these specific techniques are only preferred embodiments, and the scope of the present invention is not limited thereby. Do. That is, the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims (13)

In the midsole surface treatment composition for improving the adhesion performance between the mid-sole and at least one selected from the group consisting of shoe upper (upper), insole (in-sole) and outsole (out-sole),
The composition comprises an ethylene-vinylacetate copolymer, a crosslinking agent and a blowing agent,
The ethylene vinyl acetate copolymer is a composition for surface treatment of midsole, characterized in that the vinyl acetate (vinylacetate, VA) content is 15 to 40 parts by weight based on the total 100 parts by weight. The method of claim 1,
The composition,
It further contains an ethylene-α-olefin copolymer,
The composition for surface treatment of midsole, characterized in that the weight ratio of the ethylene vinyl acetate copolymer and the ethylene alpha olefin copolymer is 9.9:0.1 to 8:2. The method of claim 1,
The crosslinking agent,
Dicumyl peroxide (dicumyl peroxide), dibenzoyl peroxide (dibenzoyl peroxide) and di-tert butyl peroxide (di-tery-butyl peroxide) composition for the surface treatment of midsole, characterized in that selected from the group consisting of. A midsole surface treatment member for improving adhesion performance comprising the composition according to any one of claims 1 to 3. The method of claim 4,
The member,
Midsole surface treatment member, characterized in that in the form of a sheet, film or gel. A multilayer midsole in which at least one midsole surface treatment member according to claim 4 is laminated on or under the midsole. Preparing the midsole surface treatment member and the midsole according to claim 4;
Laminating the midsole surface treatment member and the midsole;
Injecting the laminated midsole surface treatment member and midsole into a midsole preform manufacturing mold and crosslinking foam to prepare a midsole preform; And
Forming the prepared midsole preform in a final mold; a multi-layer midsole manufacturing method comprising a. The method of claim 7,
The laminating step,
The method of manufacturing a multilayer midsole, characterized in that the midsole and the midsole surface treatment member are laminated at a thickness ratio of 95:5 to 90:10. The method of claim 7,
The preform manufacturing step,
A method for producing a multilayer midsole, characterized in that crosslinking foaming of the laminated midsole surface treatment member and midsole at a temperature of 150 to 180°C and a pressure of 130 to 160kgf/cm ² for 6 to 12 minutes. The method of claim 7,
The forming step,
A method for manufacturing a multilayer midsole, characterized in that the prepared midsole preform is heated at a temperature of 140 to 160°C for 5 to 7 minutes and then cooled to room temperature. A multilayer midsole manufactured by the method according to claim 7. The method of claim 11,
The multilayer midsole,
A multi-layered midsole, characterized in that the adhesive strength with at least one selected from the group consisting of shoe upper, insole and outsole is 3.0 to 4.0 kgf/cm. The method of claim 11,
The multilayer midsole,
Multilayer midsole, characterized in that the adhesive strength between the midsole surface treatment member and the midsole is 2.5 to 3.0 kgf / cm.

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