Shoe sole component and manufacturing method thereof

Abstract

To provide a lightweight and highly resilient shoe sole member suitable for sports shoes used in sports where jumping is important or for running such as jogging. [Solution] The sole members 41, 43, which are provided in the areas corresponding to the treading area and heel of the sole of the foot in the midsole 21 that constitutes part of the sole, are made of a thermoplastic polyester elastomer foam with a closed-cell structure and a skin layer formed on one or both sides, and which has a rebound resilience of 70% or more based on JIS K 6400-3:2011.

Description

[Technical Field]

[0001] The present invention relates to a shoe sole member and a method for manufacturing the same. [Background technology]

[0002] BACKGROUND ART Conventionally, there is a shoe sole member used for walking, jogging, running, etc., which is made by laminating a low-resilience foam and a high-resilience foam (Patent Document 1). Also known are shoe soles made from a combination of EVA, polyurethane foam, rubber, etc.

[0003] However, for sports where jumping is important, such as volleyball, basketball, soccer, and jumping events in track and field, or for sports shoes used for jogging, running, etc., there is a demand for lighter shoe sole components that have high rebound resilience and excellent load-bearing performance. However, when the expansion ratio of the foam is increased to achieve weight reduction, the rebound resilience decreases, and it is not possible to improve both weight reduction and rebound resilience. This is thought to be because, when the expansion ratio is increased too much, the cell structure becomes uneven and coarse, or the cells aggregate, causing many voids, resulting in a decrease in rebound resilience. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5257714 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above points, and is suitable for sports shoes used in sports where jumping is important, or for jogging, running, etc. 、 The object of the present invention is to provide a shoe sole component with high impact resilience and a method for manufacturing the same. [Means for solving the problem]

[0006] A first aspect of the present invention relates to a shoe sole member made of a thermoplastic polyester elastomer foam with a closed-cell structure and a skin layer formed on one or both sides, and having a rebound resilience of 70% or more based on JIS K 6400-3:2011.

[0007] A second aspect of the present invention is characterized in that, in the first aspect of the present invention, the thermoplastic polyester elastomer foam is a foam of a modified thermoplastic polyester elastomer obtained by modifying a thermoplastic polyester elastomer with a melt viscosity modifier.

[0008] A third aspect of the invention is the second aspect of the invention, characterized in that the melt viscosity modifier contains either 0.05 to 1.5 parts by weight of a modified styrene-acrylic copolymer or 0.01 to 1 part by weight of an acrylic-modified polytetrafluoroethylene, or 0.01 to 1.5 parts by weight of both a modified styrene-acrylic copolymer and an acrylic-modified polytetrafluoroethylene, relative to 100 parts by weight of the thermoplastic polyester elastomer.

[0009] A fourth aspect of the invention is the second aspect of the invention, characterized in that the melt viscosity modifier is an epoxy-modified styrene-acrylic copolymer and is contained in an amount of 0.1 to 1 part by weight per 100 parts by weight of the thermoplastic polyester elastomer.

[0010] A fifth aspect of the invention is characterized in that, in the second aspect of the invention, the melt viscosity modifier is an acrylic-modified polytetrafluoroethylene, and is contained in an amount of 0.01 to 0.8 parts by weight per 100 parts by weight of the thermoplastic polyester elastomer.

[0011] A sixth aspect of the present invention is characterized in that in any one of the first to fifth aspects, the sole member is provided in the midsole at portions corresponding to the tread portion and heel portion of the sole of the foot.

[0012] A seventh aspect of the invention is a method for producing a shoe sole member made of a thermoplastic polyester elastomer foam, comprising: a melting step of melting a modified thermoplastic polyester elastomer in an injection molding machine; a supercritical step of bringing a physical foaming agent to a supercritical state using a supercritical device; a dispersive melt mixing step of injecting the supercritical physical foaming agent into the injection molding machine and mixing it with the molten modified thermoplastic polyester elastomer to form a dispersed molten mixture of the molten modified thermoplastic polyester elastomer and the supercritical physical foaming agent; an injection step of injecting the dispersed molten mixture from the injection molding machine into a cavity of a movable mold; and a foaming step of core-backing the movable mold to produce a thermoplastic polyester elastomer foam, wherein the thermoplastic polyester elastomer foam has a closed-cell structure with a skin layer formed on one or both sides and a rebound resilience based on JIS K 6400-3:2011 of 70% or more.

[0013] An eighth aspect of the invention is characterized in that, in the seventh aspect of the invention, the modified thermoplastic polyester elastomer is prepared by previously mixing a thermoplastic polyester elastomer and a melt viscosity modifier.

[0014] A ninth aspect of the invention is the eighth aspect of the invention, characterized in that the melt viscosity modifier contains either 0.05 to 1.5 parts by weight of a modified styrene-acrylic copolymer or 0.01 to 1 part by weight of an acrylic-modified polytetrafluoroethylene, or 0.01 to 1.5 parts by weight of both a modified styrene-acrylic copolymer and an acrylic-modified polytetrafluoroethylene, relative to 100 parts by weight of the thermoplastic polyester elastomer.

[0015] A tenth aspect of the invention is the eighth aspect of the invention, characterized in that the melt viscosity modifier is an epoxy-modified styrene-acrylic copolymer and is contained in an amount of 0.1 to 1 part by weight per 100 parts by weight of the thermoplastic polyester elastomer.

[0016] An eleventh aspect of the invention is the eighth aspect of the invention, characterized in that the melt viscosity modifier is an acrylic-modified polytetrafluoroethylene and is contained in an amount of 0.01 to 0.8 parts by weight per 100 parts by weight of the thermoplastic polyester elastomer.

[0017] A twelfth aspect of the invention is characterized in that in any one of the seventh to eleventh aspects of the invention, the physical foaming agent is nitrogen or carbon dioxide. [Effects of the Invention]

[0018] According to the present invention, a lightweight, highly resilient shoe sole member can be obtained, which is made of a thermoplastic polyester elastomer foam with a closed-cell structure and a skin layer formed on one or both sides. Furthermore, by providing the shoe sole member in the midsole at the tread and heel areas of the sole, impacts such as those generated when landing can be converted into energy, enabling efficient movement, and the foot can be protected by reducing foot wobble when landing, improving stability. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view of a shoe using an example of a shoe sole member of the present invention. [Figure 2] 3A and 3B are a plan view and a cross-sectional view of the midsole of the shoe. [Figure 3] FIG. 1 is a diagram showing various parts of the sole of the foot. [Figure 4] The configuration of the example and a table of measurement results are shown. [Figure 5] 1 shows a table of the configuration and measurement results of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0020] The shoe sole member of the present invention will now be described. The shoe sole member of the present invention is provided on a part of the shoe sole. One state in which the shoe sole member of the present invention is used is shown below. Shoe 10 shown in Fig. 1 is an example in which the shoe sole member of the present invention is used in part of the midsole 21. Reference numeral 11 denotes an upper, and 31 denotes an outsole, and the midsole 21 and the outsole 31 are members that make up the shoe sole.

[0021] As shown in Fig. 2, sole members 41, 43 according to an embodiment of the present invention are embedded in the upper surface of the midsole 21 in areas corresponding to the tread area and heel area of ​​the sole of the foot shown in Fig. 3. The sole member 41 provided in the area corresponding to the tread area acts to absorb shock applied to the area around the base of the toes when landing during jumping, running, etc., and also acts to increase the force of kicking off the ground with repulsion. On the other hand, the sole member 43 provided in the area corresponding to the heel acts to absorb shock applied to the area around the heel when landing during jumping, running, etc.

[0022] The sole member 41 provided in the region corresponding to the footbed is a horizontally long rectangle so as to act on the area from the base of the big toe to the base of the little toe. On the other hand, the sole member 43 embedded in the region corresponding to the heel is a substantially circular shape so as to act on the center of the heel. The thickness of the sole members 41, 43 embedded in the upper surface of the midsole 21 depends on the thickness of the midsole 21, but a preferred range is about 2 to 20 mm. The sole members 41, 43 may be embedded so as to penetrate the midsole 21 from top to bottom, or may be disposed on the upper or lower surface of the midsole 21.

[0023] The shoe sole members 41 and 43 are made of a thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer formed on one or both sides, and having a resilience of 70% or more based on JIS K 6400-3:2011. The density of the shoe sole members 41 and 43 is, for example, 100 to 250 kg / m 3(The density is measured in accordance with JIS K 7222:2005.) Therefore, the shoe sole member is lightweight and has excellent resilience, making it suitable for sports shoes.

[0024] The thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer can be produced by a known supercritical gas injection molding method using a thermoplastic polyester elastomer as a production raw material.

[0025] In the supercritical gas injection molding method, a molten thermoplastic polyester elastomer and a supercritical physical blowing agent are dispersed, melted, and mixed, and then injected into a mold cavity. The mold is then cored back to expand the foam to the desired expansion ratio. The foam is then cooled in the mold and removed from the mold. Removal of the foam from the mold yields a closed-cell thermoplastic polyester elastomer foam with a skin layer on the surface.

[0026] After demolding, the thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer on the surface is cut to a predetermined size while maintaining the thickness, thereby obtaining a thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer on both sides. On the other hand, after demolding, the thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer on the surface is divided into two equal parts to obtain a thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer on one side.

[0027] Examples of physical blowing agents include nitrogen, carbon dioxide, etc. When a chemical blowing agent such as azodicarbonamide (ADCA) is used instead of a physical blowing agent, the cell structure of the resulting foam tends to become coarse, so it is preferable to use a physical blowing agent.

[0028] A melt viscosity modifier is added to the closed-cell thermoplastic polyester elastomer foam having a skin layer. The melt viscosity modifier increases the viscosity of the thermoplastic polyester elastomer during production by supercritical gas injection molding, thereby forming a good cell structure. Examples of the melt viscosity modifier include modified styrene-acrylic copolymers, acrylic-modified polytetrafluoroethylene, and high-molecular-weight polyester elastomers. The melt viscosity modifiers may be used alone or in combination of two or more.

[0029] It is more preferable to use the modified styrene-acrylic copolymer or the acrylic-modified polytetrafluoroethylene as the melt viscosity modifier. In the case of the modified styrene-acrylic copolymer, the ester group of the thermoplastic polyester elastomer reacts with the modified product (reactive groups such as isocyanate groups and epoxy groups) to increase the molecular weight, thereby increasing the melt viscosity (the modified styrene-acrylic copolymer functions as a chain extender or crosslinking agent). In the case of the acrylic-modified polytetrafluoroethylene, the bundles of polytetrafluoroethylene fibers are loosened (fibrillated) by shear force, forming a fibrous network structure, thereby increasing the melt viscosity. By modifying the polytetrafluoroethylene with an acrylic, the dispersibility in the thermoplastic polyester elastomer is improved and fibrillation can be efficiently induced (the acrylic-modified polytetrafluoroethylene functions as a thixotropic agent).

[0030] The modified product (reactive group) of the modified styrene-acrylic copolymer is preferably an epoxy group. The epoxy-modified styrene-acrylic copolymer preferably has an epoxy equivalent of 200 to 2800 and a weight-average molecular weight (Mw) of 2000 to 25000, and more preferably an epoxy equivalent of 250 to 1800 and a weight-average molecular weight (Mw) of 4000 to 15000. If the epoxy equivalent of the epoxy-modified styrene-acrylic copolymer is less than 200, a sufficient viscosity-adjusting effect cannot be obtained. If the epoxy equivalent exceeds 2800, the viscosity increases excessively, which may adversely affect moldability. Furthermore, if the weight-average molecular weight of the epoxy-modified styrene-acrylic copolymer is less than 2000, the copolymer may volatilize during molding or bleed out onto the surface of the molded article, potentially contaminating the surface of the foam. On the other hand, if the weight average molecular weight exceeds 25,000, the reactivity with the ester group of the thermoplastic polyester elastomer decreases, making it difficult to appropriately adjust the viscosity or reducing the compatibility with the thermoplastic polyester elastomer. The epoxy equivalent was measured in accordance with JIS K7236:2001.

[0031] The amount of the epoxy-modified styrene-acrylic copolymer added is preferably 0.05 to 1.5 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of the thermoplastic polyester elastomer. If the amount is less than 0.05 parts by weight, the effect of the epoxy-modified styrene-acrylic copolymer in adjusting the melt viscosity is small, while if the amount is more than 1.5 parts by weight, the viscosity of the thermoplastic polyester elastomer becomes too high, which tends to deteriorate moldability.

[0032] The amount of the acrylic-modified polytetrafluoroethylene added is preferably 0.01 to 1 part by weight, more preferably 0.01 to 0.8 parts by weight, per 100 parts by weight of the thermoplastic polyester elastomer. If the amount is less than 0.01 part by weight, the effect of adjusting the melt viscosity by the acrylic-modified polytetrafluoroethylene is small, while if the amount is more than 1 part by weight, the viscosity of the thermoplastic polyester elastomer becomes too high, which tends to deteriorate moldability.

[0033] When two or more types of melt viscosity modifiers are used in combination, the type and amount can be changed as appropriate. The total amount of the melt viscosity modifiers added is preferably 0.01 to 1.5 parts by weight per 100 parts by weight of the thermoplastic polyester elastomer. If the amount is less than 0.01 part by weight, the effect of adjusting the melt viscosity is small, while if the amount exceeds 1.5 parts by weight, the viscosity of the thermoplastic polyester elastomer becomes too high, tending to deteriorate moldability.

[0034] The thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer may contain additives other than the melt viscosity modifier, as needed. Examples of additives include colorants, synthetic resin stabilizers (antioxidants, ultraviolet absorbers, etc.), and fillers. Considering the effect on the physical properties of the foam, the additives are preferably in the form of solid raw materials such as pellets or powder.

[0035] The expansion ratio of the thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer can be adjusted by the weight of the resin (thermoplastic polyester elastomer + melt viscosity modifier + supercritical physical blowing agent; hereinafter simply referred to as resin) filled into the cavity before core-backing and the amount of resin used to core-back the mold. The expansion ratio can be increased by increasing the final cavity volume after core-backing. The expansion ratio of the thermoplastic polyester elastomer foam having a closed-cell structure and a skin layer is preferably 4 to 10 times, more preferably 5 to 9 times.

[0036] The presence of the skin layer improves the mechanical strength, such as tensile strength, of the foam, and the surface strength, such as abrasion resistance, and furthermore, since the load applied to the foam is received by the surface, the load is dispersed, preventing the foam from setting, and high resilience is obtained. The skin layer is formed by filling the resin into a mold and cooling it in contact with the inner wall of the cavity.

[0037] The weight of resin to be filled into the cavity before core-back can be either a full shot equal to the cavity capacity or a short shot less than the cavity capacity. In the case of a short shot, the resin weight injected into the cavity is 5 to 20% less by weight than the resin weight that can be filled into the cavity volume. [Example]

[0038] The following thermoplastic polyester elastomer (abbreviated as TPEE) and melt viscosity modifier were blended as shown in FIG. 4, and samples of Examples 1 to 16 and Comparative Examples 1 to 7 for measuring physical properties were produced by supercritical gas injection molding. Thermoplastic polyester elastomer 1 (TPEE-1): Product name: Pelprene P-40BTM, manufactured by Toyobo Co., Ltd. Thermoplastic polyester elastomer 2 (TPEE-2): Product name: Pelprene P-30B, manufactured by Toyobo Co., Ltd. Thermoplastic polyester elastomer 3 (TPEE-3): Product name: Pelprene P-40B, manufactured by Toyobo Co., Ltd. Melt viscosity modifier-1: Epoxy-modified styrene-acrylic copolymer, epoxy equivalent = 714, weight average molecular weight = 9700 Melt viscosity modifier-2: Epoxy-modified styrene-acrylic copolymer, epoxy equivalent = 285, weight average molecular weight = 7300 Melt viscosity modifier-3: Epoxy-modified styrene-acrylic copolymer, epoxy equivalent = 1500, weight average molecular weight = 8500 Melt viscosity modifier-4: Epoxy-modified styrene-acrylic copolymer, epoxy equivalent = 2800, weight average molecular weight = 2900 Melt viscosity adjuster-5: Product name: Metablen A-3800 (acrylic modified polytetrafluoroethylene), manufactured by Mitsubishi Rayon Co., Ltd. Physical foaming agent: Nitrogen gas

[0039] The injection molding machine used was an electric injection molding machine, and the mold used had a cavity of 100 x 200 mm between the movable and fixed molds, and was configured so that the initial thickness could be varied from 0.5 mm to 5.0 mm.

[0040] Nitrogen gas was brought to a supercritical state using a supercritical feeder and then injected into the cylinder of an injection molding machine, and the thermoplastic polyester elastomer and melt viscosity modifier, which were in a molten state in the cylinder, were heated to a crystalline melting point of 180°C or higher, and the nitrogen gas was dispersed, melted, and mixed. The mixture was then injected into the cavity of a mold, and the movable mold was cored back. After cooling, the mixture was demolded to obtain a thermoplastic polyester elastomer foam with a closed-cell structure and a skin layer on the surface.

[0041] Alternatively, a modified thermoplastic polyester elastomer may be prepared by premixing (reacting or fibrillating) a thermoplastic polyester elastomer with a melt viscosity modifier, followed by the above-described method to obtain a closed-cell thermoplastic polyester elastomer foam having a skin layer on the surface. The modified thermoplastic polyester elastomer undergoes a reaction between the ester groups of the thermoplastic polyester elastomer and the epoxy groups of the epoxy-modified styrene-acrylic copolymers (melt viscosity modifiers 1 to 4), thereby lengthening the molecular chain of the thermoplastic polyester elastomer and crosslinking the thermoplastic polyester elastomers to increase the molecular weight. Furthermore, fibrillation of the polytetrafluoroethylene in the acrylic-modified polytetrafluoroethylene (melt viscosity modifier 5) increases the viscosity during melting. To obtain a good cell structure, the use of a modified thermoplastic polyester elastomer is preferred.

[0042] In Example 1, TPEE-2 was used as the thermoplastic polyester elastomer, 0.5 parts by weight of melt viscosity modifier-1 (epoxy-modified styrene-acrylic copolymer) was added, the initial cavity thickness (initial thickness) was set to 2 mm, and the resin was filled to 100% of the cavity volume (full shot).The mold was then opened with a core-back depth of 17 mm to produce a 19 mm thick, closed-cell thermoplastic polyester elastomer foam (expansion ratio 9.5 times) with a skin layer on the surface.The specific gravity of the resin to be filled was assumed to be 1, and the weight was converted to volume to calculate the filling rate (filling ratio) relative to the cavity volume.

[0043] In Example 2, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that the core-back amount was set to 12 mm.

[0044] In Example 3, a thermoplastic polyester elastomer foam (expansion ratio 5.5 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 11 mm in the same manner as in Example 1, except that the core-back amount was set to 9 mm.

[0045] In Example 4, a thermoplastic polyester elastomer foam (expansion ratio: 4.4 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 8.8 mm in the same manner as in Example 1, except that the core-back amount was set to 6.8 mm.

[0046] In Example 5, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that the amount of melt viscosity modifier-1 added was changed to 0.05 parts by weight and the core-back length was changed to 12 mm.

[0047] In Example 6, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that the amount of melt viscosity modifier-1 added was changed to 0.1 parts by weight and the core-back length was changed to 12 mm.

[0048] In Example 7, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that the amount of melt viscosity modifier-1 added was changed to 1 part by weight and the core-back length was changed to 12 mm.

[0049] In Example 8, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that the amount of melt viscosity modifier-1 added was changed to 1.5 parts by weight and the core-back amount was changed to 12 mm.

[0050] In Example 9, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a thickness of 14 mm and a closed-cell structure having a skin layer on the surface was produced in the same manner as in Example 1, except that the thermoplastic polyester elastomer was changed to TPEE-3 and the core-back amount was set to 12 mm.

[0051] In Example 10, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that the melt viscosity modifier-2 (epoxy-modified styrene-acrylic copolymer) was used in an amount of 0.5 parts by weight and the core-back length was 12 mm.

[0052] In Example 11, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that melt viscosity modifier-3 (epoxy-modified styrene-acrylic copolymer) was used in an amount of 0.5 parts by weight and the core-back length was 12 mm.

[0053] In Example 12, a thermoplastic polyester elastomer foam (expansion ratio 7 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 14 mm in the same manner as in Example 1, except that the melt viscosity modifier-4 (epoxy-modified styrene-acrylic copolymer) was used in an amount of 0.5 parts by weight and the core-back length was 12 mm.

[0054] In Example 13, a thermoplastic polyester elastomer foam (expansion ratio 5 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 10 mm in the same manner as in Example 1, except that the melt viscosity modifier-5 (acrylic-modified polytetrafluoroethylene) was used in an amount of 0.01 parts by weight and the core-back length was 8 mm.

[0055] In Example 14, a thermoplastic polyester elastomer foam (expansion ratio 5 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 10 mm in the same manner as in Example 1, except that the melt viscosity modifier-5 was changed to 0.8 parts by weight and the core-back amount was changed to 8 mm.

[0056] In Example 15, a thermoplastic polyester elastomer foam (expansion ratio 5 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 10 mm in the same manner as in Example 1, except that the melt viscosity modifier-5 was changed to 1 part by weight and the core-back amount was changed to 8 mm.

[0057] In Example 16, a thermoplastic polyester elastomer foam (expansion ratio 5 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 10 mm in the same manner as in Example 1, except that 0.5 parts by weight of melt viscosity modifier-1 and 0.1 parts by weight of melt viscosity modifier-5 were added in combination and the core-back amount was set to 8 mm.

[0058] As comparative examples, specimens were prepared for Comparative Examples 1 to 7 in which no melt viscosity modifier was added, Comparative Example 8 made of polyurethane foam, and Comparative Example 9 made of thermoplastic polyurethane foam beads. The configuration of each comparative example is shown in Figure 5.

[0059] In Comparative Example 1, TPEE-1 was used as the thermoplastic polyester elastomer, the initial thickness of the cavity space (initial thickness) was set to 2 mm, the resin was filled to 100% of the cavity volume (full shot), the core-back amount was set to 0 mm, and the mold was opened to produce a thermoplastic polyester elastomer foam (expansion ratio 1) with a closed-cell structure and a skin layer on the surface, with a thickness of 2 mm.

[0060] In Comparative Example 2, a thermoplastic polyester elastomer foam (expansion ratio 2x) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 4 mm in the same manner as in Comparative Example 1, except that the core-back amount was set to 2 mm.

[0061] In Comparative Example 3, a thermoplastic polyester elastomer foam (expansion ratio 3 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 6 mm in the same manner as in Comparative Example 1, except that the core-back amount was set to 4 mm.

[0062] In Comparative Example 4, a thermoplastic polyester elastomer foam (expansion ratio 4 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 8 mm in the same manner as in Comparative Example 1, except that the core-back amount was set to 6 mm.

[0063] In Comparative Example 5, a thermoplastic polyester elastomer foam (expansion ratio 5 times) with a closed-cell structure and a skin layer on the surface was produced in a thickness of 10 mm in the same manner as in Comparative Example 1, except that the core-back amount was changed to 8 mm.

[0064] Comparative Example 6 was the same as Comparative Example 1 except that the thermoplastic polyester elastomer was changed to TPEE-2, the initial thickness of the cavity space (initial thickness) was set to 2 mm, and the core-back amount was set to 5 mm. A thermoplastic polyester elastomer foam (expansion ratio 3.5 times) with a closed-cell structure and a skin layer on the surface was produced with a thickness of 7 mm.

[0065] In Comparative Example 7, the thermoplastic polyester elastomer was changed to TPEE-3, the initial thickness of the cavity space (initial thickness) was set to 2 mm, and the core-back amount was set to 4 mm. The same procedures were followed as in Comparative Example 1, and a thermoplastic polyester elastomer foam (expansion ratio: 3) with a closed-cell structure and a skin layer on the surface was produced with a thickness of 6 mm.

[0066] Comparative Example 8 has a density of 45 kg / m 3 The polyurethane foam (without a skin layer), product number ERG-H, manufactured by Inoac Corporation, was used. Comparative Example 9 has a density of 300 kg / m 3 Thermoplastic polyurethane foam beads (without a skin layer), product number: MC380, manufactured by NTW Co., Ltd., were used.

[0067] The density, impact resilience, and load increase rate of each sample of each example and comparative example for measuring physical properties were measured, and the appearance was visually evaluated. The results are shown in Figures 4 and 5. Density was measured based on JIS K 7222:2005 by cutting each of the samples of Examples 1 to 16 and Comparative Examples 1 to 7 to prepare density measurement samples of 30φ×thickness of each sample, and for Comparative Examples 8 and 9, cutting was performed from 10 mm slices to prepare density measurement samples of 30φ×10 mm thickness, and the density was measured based on JIS K 7222:2005. The density measurement samples had skin layers on both sides, except for Comparative Examples 8 and 9. As with density, the rebound resilience was measured by cutting samples from each Example and Comparative Example to prepare a 100mm square sample of each sample thickness for measuring rebound resilience, and when the sample for measuring rebound resilience was less than 10mm, the samples were stacked to a total thickness of 10mm or more and measured according to JIS K 6400-3: 2011. The samples for measuring rebound resilience had skin layers on both sides, except for Comparative Examples 8 and 9.

[0068] The load increase rate was determined by measuring the maximum load value (N) in a three-point bending test, and calculating the load increase rate from the ratio of the measured value (A) of Comparative Example 1, which has an expansion rate of 1 (non-expanded), to the measured value (B) of each Example and Comparative Examples 2 to 9, using the following formula: [Load increase rate (times)] = [B(N)] / [A(N)] In the three-point bending test, as with the density test, samples for measuring the load increase rate were cut from each example and comparative example to prepare samples of 100 mm length x 10 mm width x thickness for each sample, and measurements were performed at a support distance of 60 mm and a test speed of 2 mm / min. The measurements were performed using an AUTO GRAPH AG-IS made by Shimadzu Corporation, and the support stand and indenter used were those specified in JIS K7171 5.3. A load increase rate of 3 times or more was marked "○", a load increase rate of 2 times or more but less than 3 times was marked "△", and a load increase rate of less than 2 times was marked "×".

[0069] Regarding appearance, if the cell structure is uneven, voids and streaks will appear on the surface. Therefore, if almost no voids or streaks are visible on the surface (if the cell structure is uniform), the rating is "Good", if a few voids or streaks are visible (if the cell structure is slightly uneven), the rating is "Good", and if many voids or streaks are visible (if the cell structure is significantly uneven), the rating is "Poor".

[0070] Examples 1 to 9 (using melt viscosity modifier-1) had a density of 110 to 240 kg / m 3 The foams had a rebound resilience of 70 to 77% and a load increase rate of 3.0 to 5.2 times, and were lightweight, high in rebound resilience, and a high load increase rate. In particular, Examples 1 to 4, 6, 7, and 9, which contained 0.1 to 1.0 parts by weight of melt viscosity modifier-1, had a rebound resilience of 71 to 77%, and were evaluated as "good" in appearance, which were favorable. Furthermore, Examples 1 to 3, 6, 7, and 9, which contained 0.1 to 1.0 parts by weight of melt viscosity modifier-1 and had an expansion ratio of 5.5 times or more, had a density of 110 to 190 kg / m 3 The melt viscosity modifier-1 was added in an amount of 0.1 to 1.0 parts by weight, and the foaming ratio was 7 times or more. 3 The impact resilience was 71 to 75%, and the ball was lighter while maintaining high impact resilience.

[0071] In Example 10 (using melt viscosity modifier-2), the density was 150 kg / m 3 The impact resilience was 76%, and it was particularly lightweight and had high impact resilience, with a high load increase rate of 3.7 times.

[0072] In Example 11 (using melt viscosity modifier-3), the density was 150 kg / m 3 The impact resilience was 74%, and it was particularly lightweight and had high impact resilience, with a high load increase rate of 3.2 times.

[0073] In Example 12 (using melt viscosity modifier-4), the density was 150 kg / m 3 The impact resilience was 71%, making it lightweight, high impact resilience, and the load increase rate was 3.1 times higher.

[0074] In Examples 13 to 15 (using melt viscosity modifier-5), the density was 200 kg / m 3 The impact resilience was 70 to 71%, and the load increase rate was 3.0 to 3.1 times, so they were lightweight, had high impact resilience, and also had a high load increase rate. In particular, Examples 13 and 14, which contained 0.01 to 0.8 parts by weight of melt viscosity modifier-5, were evaluated as "good" in appearance and were favorable.

[0075] In Example 16 (a combination of melt viscosity modifier-1 and melt viscosity modifier-5), the density was 200 kg / m 3 The impact resilience was 75%, and the load increase rate was 5.1 times, making it lightweight, high impact resilience, and high load increase rate. Even when melt viscosity modifier-1 and melt viscosity modifier-5 were used in combination, the appearance was evaluated as "Good", which was favorable.

[0076] As shown in the measurement results in Figure 4, by using an epoxy-modified styrene-acrylic copolymer (melt viscosity modifiers 1 to 4) having an epoxy equivalent of 200 to 2800 and a weight-average molecular weight (Mw) of 2000 to 25000 as a melt viscosity modifier, a lightweight thermoplastic polyester elastomer foam with high impact resilience can be obtained, and the load increase rate is three times or more, and the density is 110 to 240 kg / m 3 Even if the foam is light, deterioration of mechanical properties can be suppressed. In particular, by using an epoxy-modified styrene-acrylic copolymer (melt viscosity modifiers 1 to 3) having an epoxy equivalent of 250 to 1,800 and a weight-average molecular weight (Mw) of 4,000 to 15,000, a thermoplastic polyester elastomer foam that is lighter and has higher impact resilience can be obtained.

[0077] In contrast, Comparative Examples 1 to 7, which did not contain a melt viscosity modifier, Comparative Example 8, which consisted of polyurethane foam, and Comparative Example 9, which consisted of thermoplastic polyurethane foam beads, were inferior in lightness, had low impact resilience, or both, and had a low rate of load increase. The measurement results of the comparative examples are described in detail below.

[0078] In Comparative Example 1, the foaming ratio was 1, and the impact resilience was high at 78%, which was the same as that of Example 4, but the density was 1050 kg / m 3 The load increase rate was 1.0 times, which was extremely poor in terms of lightness and low in terms of load increase rate. In Comparative Example 2, the expansion ratio was 2 times and the density was 530 kg / m 3 The impact resilience was 66%, and the load increase rate was 1.9 times, and the lightness, impact resilience, and load increase rate were all inferior to those of the Examples. In Comparative Example 3, the expansion ratio was 3 times and the density was 350 kg / m 3 The impact resilience was 62%, and the load increase rate was 2.5 times, and the lightness, impact resilience, and load increase rate were all inferior to those of the Examples.

[0079] In Comparative Example 4, the expansion ratio was 4 times, which was almost the same as that of Example 4, but the impact resilience was 62%, which was a lower value than that of Example 4. Furthermore, the density of Comparative Example 4 was 260 kg / m 3 The load increase rate was 2.7 times, which was higher than the density of Example 4, and the lightweight property and load increase rate were inferior. In Comparative Example 5, the expansion ratio was 5 times, which was almost the same as that of Example 3, but the impact resilience was 55%, which was a lower value than that of Example 3. Furthermore, the density of Comparative Example 5 was 210 kg / m 3 The load increase rate was 2.6 times, which was higher than the density of Example 3, and the weight was poor and the load increase rate was poor. In Comparative Example 6, the expansion ratio was 3.5 times and the density was 300 kg / m 3 The impact resilience was 65%, and the load increase rate was 2.6 times, and the lightness, impact resilience, and load increase rate were all inferior to those of the Examples. In Comparative Example 7, the expansion ratio was 3 times and the density was 350 kg / m 3 The impact resilience was 60%, and the load increase rate was 2.3 times, and the lightness, impact resilience, and load increase rate were all inferior to those of the Examples.

[0080] Comparative Example 8 is made of polyurethane foam and has a density of 45 kg / m 3 and was excellent in lightness, but the rebound resilience was 50% and the load increase rate was 1.4 times, which were lower than those of the Examples. Comparative Example 9 is made of thermoplastic polyurethane foam beads and has a density of 300 kg / m 3 The impact resilience was 61%, and the load increase rate was 2.9 times, and the lightness, impact resilience, and load increase rate were all inferior to those of the Examples.

[0081] As described above, each of the examples is lightweight and has high resilience, making it suitable for use as a shoe sole member. The shoe sole member of the present invention is not limited to being provided on a part of the midsole, but may be provided on the entire surface or a wide range, or may be provided on other shoe sole components. [Explanation of symbols]

[0082] 10. Shoes 21 Midsole 41, 43 Shoe sole materials

Claims

[Claim 1] A method for producing a shoe sole member made of a thermoplastic polyester elastomer foam, comprising: a melting step of melting a modified thermoplastic polyester elastomer obtained by modifying the thermoplastic polyester elastomer with a melt viscosity modifier that increases the viscosity of the thermoplastic polyester elastomer in an injection molding machine; a supercritical step of bringing the physical foaming agent into a supercritical state using a supercritical device; a dispersive melt mixing step of injecting the physical blowing agent in a supercritical state into the injection molding machine and mixing it with the modified thermoplastic polyester elastomer in a molten state to form a dispersed melt mixture of the modified thermoplastic polyester elastomer in a molten state and the physical blowing agent in a supercritical state; an injection step of injecting the dispersed molten mixture from the injection molding machine into a cavity of a movable mold; a foaming step of core-backing the movable mold to produce a thermoplastic polyester elastomer foam, the thermoplastic polyester elastomer foam has a rebound resilience based on JIS K 6400-3:2011 of 71% or more and a closed-cell structure with a skin layer formed on one or both sides; The method for manufacturing a shoe sole member, wherein the thermoplastic polyester elastomer foam has a maximum load value of 1.42 N or more in a three-point bending test.

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