KR20210013825A - Polymer Composition Urethane Outsole - Google Patents

Abstract

The present invention relates to a polymer compressed urethane outsole, and more specifically, to an outsole of a shoe capable of absorbing shock when walking by providing elasticity to a sole of the shoe and including an elastic structure for providing convenience when walking. Polymer compressed urethane is manufactured by using a polymer compressed urethane composition characterized by including 1-2 parts by weight of a stearic acid for 100 parts by weight of thermoplastic resin including 75-92 wt% of a thermoplastic urethane elastic body and 8-25 wt% of natural rubber.

Description

Polymer Composition Urethane Outsole

The present invention relates to a polymer compression urethane sole, and in detail, in constructing the outsole of a shoe, an elastic structure is provided to provide comfort when walking, while allowing an elastic force to be imparted to the shoe sole to absorb shock while walking It relates to a polymeric compression urethane sole having a.

In general, shoes are worn on the feet of a person to increase the fit of the feet while protecting the feet under the greatest load on the human body.Shoes have various functions to support or distribute the body load elastically. And structure.

Among these shoes, unlike sneakers, sneakers, and slippers, it is common to use a hard heel, which reduces the stability of the shoe, and the wearer experiences a lot of discomfort and fatigue, and in severe cases, various foot diseases occur.

Thus, in recent years, shoes using an elastic material have been proposed in order to solve the above problems.

However, in spite of such a proposal, a considerable cost is required and the problem that the wearer still feels deteriorated has not been solved.

On the other hand, among various thermoplastic elastomer materials, there have been many studies to use thermoplastic 　 urethane 　 elastic body (TPU) with excellent abrasion resistance for shoe outsoles, but at high hardness, wear resistance is excellent, but the feeling of wearing is poor, and appropriate hardness (65 ~ In 75), the abrasion resistance is insufficient and the slip resistance in the wet state is not good, so that the commercialization is not yet available. In addition, when the floor surface is very smooth, there is a problem in marking that marks remain on the floor surface during friction.

In addition, Korean Patent No. 10-1402987 discloses that thermoplastic 　 urethane 　 elastomer (TPU) is for shoe outsoles with improved wear resistance and wet slip resistance compared to thermoplastic 　 urethane 　 elastomer (TPU) when blending a predetermined amount of ethylene-propylene-diene rubber (EPDM). Proposing a composition.

However, in the case of such a composition, the higher the repulsion elasticity value, the better the material in terms of kinematics. However, this composition has a limitation in providing excellent repulsion elasticity to consumers as the repulsion elasticity value is 53% or less.

Therefore, although injection molding is possible, a thermoplastic 　 urethane elastomer with improved abrasion resistance, wet slip resistance and repulsion elasticity, which is more suitable as a material for shoe outsoles at an appropriate hardness of about 65 to 75, has not been developed yet.

As described above, the present invention has been devised to solve the above problems, and provides stability and comfort when walking by using an outsole made of polymer compressed urethane, and elasticity to enable prevention of foot diseases. We want to provide a structured sole.

On the other hand, the inventors of the present invention were researching thermoplastic 　 urethane 　 elastomers for shoe outsoles, unlike the existing method of improving the abrasion resistance by blending a polymer with excellent abrasion resistance, although the abrasion resistance of natural rubber itself is not better than the conventional thermoplastic 　 urethane 　 elastics , When blending an appropriate amount of natural rubber with a thermoplastic 　 urethane 　 elastomer by a melt compounding method, it was found that abrasion resistance, wet slip resistance, and resilience elasticity were better than the existing thermoplastic 　 urethane 　 elastic bodies.

Accordingly, an object of the present invention is to provide a thermoplastic rubber composition for a shoe outsole with improved wear resistance, wet slip resistance and resilience without a crosslinking process, and a shoe sole using the same.

As a specific means for achieving the above object, 75 to 92% by weight of thermoplastic 　 urethane 　 elastomer; And 8 to 25% by weight of natural rubber; With respect to 100 parts by weight of the thermoplastic resin containing; 1 to 2 parts by weight of stearic acid; characterized in that it is made using a polymer compression urethane composition and a composition thereof Provide the sole of the shoe.

The present invention provides a sole using a polymer compressed urethane, the polymer compressed urethane outsole has good elasticity in terms of its material, and can provide a stable fit to the wearer at a relatively low cost.

In addition, the thermoplastic polyurethane 　 and natural rubber blend composition according to the present invention can be effectively used to produce a product because manufacturing cost is reduced and injection molding is possible without an additional crosslinking agent and crosslinking process.

In particular, the thermoplastic rubber composition according to the present invention can be used as a material for a shoe outsole because it has a hardness suitable for a shoe outsole and has improved abrasion resistance, wet slip resistance, and resilience.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals have been used for similar elements.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The term "and/or" includes a combination of a plurality of related stated items or any of a plurality of related stated items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, 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. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

Hereinafter, a preferred embodiment of the present invention will be described in more detail.

This 　invention is a thermoplastic polyurethane 　 blend composition for shoe outsoles, characterized in that it contains 1 to 2 parts by weight of stearic acid, based on 100 parts by weight of a thermoplastic resin containing 75 to 92% by weight of an elastic body and 8 to 25% by weight of natural rubber. Provides.

At this time, the thermoplastic 　 urethane 　 elastomer is a segmented block copolymer consisting of a hard segment (a rigid molecular chain) and a soft segment (a flexible molecular chain), and each segment is a microphase separation phenomenon due to thermodynamic incompatibility with each other. To form a hard domain and a soft domain, respectively, and the hard domains are linked by hydrogen bonds between molecules to act as a physical crosslinking point of the soft domain.

As the thermoplastic 　 urethane 　 elastomer, an ester-based or ether-based thermoplastic 　 urethane 　 elastomer may be used. At this time, if the content of the thermoplastic 　 urethane 　 elastomer is less than 75% by weight, there is a problem that abrasion resistance is lowered, and when it exceeds 92% by weight, it is used in the above range because it is not suitable for use as a shoe outsole due to high hardness and low wet slip resistance. It is desirable to do. More preferably, thermoplastic 　 urethane 　 elastomer: natural rubber is used in a ratio of 9:1 by weight.

As the natural rubber (NR), it is preferable to use a natural rubber having a glass transition temperature lower than the glass transition temperature (Tg) of the soft segment of the thermoplastic 　 urethane 　 elastic body. If a natural rubber with a glass transition temperature higher than that of the soft segment glass transition temperature of thermoplastic 　 urethane 　 elastomer is used, the effect of increasing wear resistance cannot be seen.

When natural rubber is mixed in a predetermined amount with thermoplastic 　 urethane 　 elastomer, the flexible and non-polar natural rubber is not compatible with the hard segment of urethane 　, which is highly polar and rigid, and is not compatible with the hard segment of urethane 　. As a result of the soft segment being softer, micro-phase separation occurs more easily.

However, in the case of natural rubber, the molecular weight is large, so micro-phase separation can occur more easily when stearic acid is used.

As the degree of micro-phase separation increases, mechanical properties increase. This is known to those skilled in the art, and according to these properties, natural rubber itself has less wear resistance than thermoplastic 　 urethane 　 elastomers, but it increases the wear resistance of thermoplastic 　 urethane 　 elastomers when compounded in a predetermined amount.

At this time, when the content of the natural rubber (NR) is less than 8% by weight, it is not suitable for use as a shoe outsole due to its high hardness and low wet slip resistance, and when it exceeds 25% by weight, the compatibility with thermoplastic 　 urethane 　 elastomer decreases. It is preferable to use it in the above range since its wear resistance is reduced than that of thermoplastic 　 urethane 　 elastic bodies.

In addition, it is preferable to use 1 to 2 parts by weight of stearic acid based on 100 parts by weight of the thermoplastic resin. When stearic acid is used in an amount less than 1 part by weight and more than 2 parts by weight, it is recommended to use it within the above range since the wear resistance is lower than that of thermoplastic 　 urethane 　 elastomers.

In addition, in the present invention, 1 to 5 parts by weight of a rubber filler may be used based on 100 parts by weight of the thermoplastic resin. As the filler, those that can be used as conventional rubber fillers may be used according to the choice of a person skilled in the art. It is better to use silica.

In addition, 0.5 to 5 parts by weight of processing oil such as silicone oil may be used based on 100 parts by weight of the base material to reduce friction, and in addition, antioxidants commonly used in the art, zinc stearate to prevent adhesion during kneading. Various additives such as lubricants, etc. may be appropriately selected and used.

In addition, it is preferable to blend natural rubber with the thermoplastic 　 urethane 　 elastomer by melt-compounding. This is because the melt compounding method has the lowest cost and is currently most commonly used in manufacturing in the art.

Meanwhile, the thermoplastic polyurethane blend composition according to the present invention may be manufactured in a pellet form using a closed mixer or extruder, and then injection-processed to manufacture a shoe sole.

In other words, the thermoplastic polyurethane 　 blend composition according to the present invention manufactures a thermoplastic rubber composition by mixing natural rubber with a thermoplastic 　 urethane 　 elastic body to have a hardness suitable for application as a shoe sole, thereby simplifying the manufacturing process and injection molding because there is no need for a crosslinking process. This is possible to provide a composition for a shoe outsole that is more suitable than a conventional shoe outsole composition. In addition, abrasion resistance, wet slip resistance, and rebound elasticity are improved, so it can be widely used for shoe soles.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

Examples 1 to 2

The composition shown in Table 1 was put into a hermetic mixer and kneaded by melt compounding for 10 minutes so as to be uniformly dispersed. At this time, it is desirable to keep the temperature inside the mixer at 160°C to minimize aging due to heat inside the mixer. After the above-described kneading process, an appropriate amount of the composition is put into a flat plate mold having a thickness of 2 mm in a closed tube, and then pressed for 5 minutes under high temperature/high pressure of 160°C and 150 kg/㎠ using a press machine, and then using a cooling press machine. A specimen was prepared by pressing for 2 minutes under a low temperature/high pressure of 100 kg/cm 2 at a temperature around 20°C.

Comparative Examples 1 to 4

Specimens were prepared using the composition shown in Table 1 below in the same manner as in Examples 1 to 2.

The physical properties of the specimens prepared according to Examples 1 to 2 and Comparative Examples 1 to 4 were measured in the following manner, and the thermoplastic polyurethane 　 blend composition and the physical property values are shown in Table 1 below.

division Example 1 Example 2 Substrate (% by weight) Thermoplastic urethane elastomer (TPU) 90 80 Natural rubber (NR) 10 20 Ethylene-propylene-diene rubber (EPDM) - - Total amount 100 100 Additive (parts by weight) Stearic acid One One Properties Hardness (Shore A type) 71 67 importance 1.13 1.97 Wear resistance (NBS, %) 1072 639 Wet slip resistance (wet dynamic friction coefficient) 0.39 0.36 Rebound elasticity (%) 62 65 division Comparative Example 1 Comparative Example 2 Substrate (% by weight) Thermoplastic urethane elastomer (TPU) 100 70 Natural rubber (NR) - 30 Ethylene-propylene-diene rubber (EPDM) - - Total amount 100 100 Additive (parts by weight) Stearic acid One One Properties Hardness (Shore A type) 76 60 importance 1.17 1.07 Wear resistance (NBS, %) 500 309 Wet slip resistance (wet dynamic friction coefficient) 0.21 0.30 Rebound elasticity (%) 51 69 division Comparative Example 3 Comparative Example 4 Substrate (% by weight) Thermoplastic urethane elastomer (TPU) 90 90 Natural rubber (NR) 10 - Ethylene-propylene-diene rubber (EPDM) - 10 Total amount 100 100 Additive (parts by weight) Stearic acid 0 One Properties Hardness (Shore A type) 73 75 importance 1.13 1.14 Wear resistance (NBS, %) 475 590 Wet slip resistance (wet dynamic friction coefficient) 0.38 0.4 Rebound elasticity (%) 63 53

Experimental Examples The specimens prepared according to Examples 1 to 2 and Comparative Examples 1 to 4 were measured for physical properties in the following manner, and the results are shown in Table 1 above.

1. Hardness: It was measured using the method of ASTM D2240.

2. Specific gravity: In order to measure the specific gravity of the specimen, the specific gravity was measured using a hydrometer (ALFA Mirage model SD-200L) according to ASTM D792.

3. Abrasion resistance (NBS): To measure the abrasion resistance properties of the test specimen, the NBS wear test (KS M6625) was used, and it was calculated by Equation 1 below.

In Equation 1, AI is the wear resistance rate (%), R1 is the number of revolutions required to wear the specimen to be tested 2.54 mm, and R2 is the average number of revolutions when the reference specimen for wear (RMA) wears 2.54 mm. .

4. Slip resistance (wet dynamic friction coefficient): Slip characteristics were measured according to ASTM D1894-76 using a friction tester (Version 1.0) of LLOYD Instruments Ltd. The evaluation of the properties of the wet state was measured by applying sufficient moisture to the glass surface, which is the bottom of the test, and the wet coefficient of kinetic friction was calculated by the following equation.

Where B is the average force to sustain the sled's movement and W is the sled's weight in grams.

5. Rebound elasticity: The rebound elasticity of the specimen was measured using the DIN 53512 method. The specimen was in the form of a cylinder (diameter 29 mm, thickness 12.5±0.5 mm), and after moving from the guide scale to 100 positions of the iron bar guide from the 0 position, it fell 4 times, read from 5 times, and measured 3 times.

As shown in Table 1, the specimen using the thermoplastic rubber composition for the TPU/NR shoe outsole prepared according to Example 1 of the present invention exhibited an NBS wear test result, and an NBS mardo degree of 1072. And the specimen using the thermoplastic rubber composition for the TPU/NR shoe outsole prepared according to Example 2 showed an NBS abrasion degree of 639 as a result of the NBS wear test.

When compared with the NBS wear of the specimen of Comparative Example 1 prepared using only the same thermoplastic 　 urethane 　 elastic body (TPU) as in Examples 1 and 2 as a substrate, it was confirmed that the wear resistance of Examples 1 and 2 was improved.

In addition, it was confirmed that the wet dynamic friction coefficient of Example 1 was 0.39 and the wet dynamic friction coefficient of Example 2 was 0.36, which was more excellent when compared to the wet dynamic friction coefficient of Comparative Example 1 of 0.21.

That is, in the case of the NBS abrasion degree, the larger the value, the better the abrasion resistance, and the larger the wet dynamic friction coefficient, the better the wet slip resistance.

In addition, it can be seen that the specimens prepared according to Examples 1 and 2 had hardness of 71 and 67, respectively, which is suitable for use as a shoe outsole. In comparison, the specimen of Comparative Example 1 has a high hardness of 76, and generally exhibits excellent abrasion resistance when the hardness is high.The specimens prepared according to Examples 1 and 2 of the present invention have a hardness suitable for use as a shoe outsole. Although it was reduced, it can be seen that the NBS wear was higher than that of the specimen of Comparative Example 1 having high hardness. In terms of specific gravity, it can be seen that the specific gravity of the embodiment according to the present invention is also reduced and is more suitable for use as a shoe outsole.

In addition, in the present invention, the amount of natural rubber (NR) is an important factor. When comparing Comparative Example 2 with Examples 1 and 2, it can be seen that in the case of Comparative Example 2 in which 30% by weight of natural rubber was used, the wear resistance of NBS was 309, which greatly reduced the wear resistance.

In addition, in the present invention, the amount of stearic acid is also an important factor. When comparing Comparative Example 3 and Example 1, in the case of Comparative Example 3 without using stearic acid, it was found that the NBS wear was 475, which was much lower than that of Example 1, and compared to the thermoplastic 　 urethane 　 elastomer of Comparative Example It can be seen that the wear resistance is not good.

In other words, according to the present invention, when natural rubber is blended in the range of 8 to 25% by weight in the range of 75 to 92% by weight of the thermoplastic 　 urethane 　 elastomer, and 100 parts by weight of the total amount of them is 100 parts by weight, stearic acid is in the range of 1 to 2 parts by weight. Only when blended, it is possible to obtain an effect of improved abrasion resistance compared to the case of using only a thermoplastic 　 urethane elastomer.

In addition, the resilience of Example 1 and Example 2 was 62% and 65%, respectively, and Comparative Example 4 in which 51% of the resilience of Comparative Example 1 in which only thermoplastic 　 urethane 　 elastomer was used and ethylene-propylene-diene rubber (EPDM) were blended. It can be seen that the rebound resilience of Example 1 and Example 2 was significantly increased when compared with 53% of the repulsion elasticity of.

Therefore, the shoe sole manufactured using the thermoplastic polyurethane blend composition according to the present invention of the above combination can be provided as a shoe sole having excellent hardness (65-75), abrasion resistance, wet slip resistance and resilience without a crosslinking process. have.

In addition, the shoe sole according to the present invention provides stability and comfort when walking, and has an elastic structure for preventing foot disease.

Claims (1)

75 to 92% by weight of thermoplastic urethane elastomer; And
8 to 25% by weight of natural rubber; based on 100 parts by weight of a thermoplastic resin containing,
Stearic acid 1 to 2 parts by weight; characterized in that it comprises, the sole of a shoe, characterized in that made using a polymer compression urethane composition.