Sole member

Abstract

To provide a member for shoe soles that can exhibit excellent impact resilience even when the member becomes quickly deformed.SOLUTION: A member for shoe soles comprises a foam comprising a resin satisfying a following formula (1): tanδ10Hz / tanδ0.1Hz≤1.0, where tanδ10Hz: a loss tangent (23°C) which is a ratio between a storage elastic modulus and a loss elastic modulus at a frequency 10 Hz, and tanδ0.1Hz: a loss tangent (23°C) which is a ratio between a storage elastic modulus and a loss elastic modulus at a frequency 0.1 Hz.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a member for a shoe sole.

Background Art

[0002] Foamed resins are widely used in interior materials, automotive parts such as door glass runs, packaging materials, daily necessities, etc. Patent Document 1 discloses a technique of using a foam obtained by crosslinking and foaming a resin composition as an interior material of an automobile.

[0003] Since foamed resins can achieve weight reduction, they are also used as members for shoe soles. The foamed resins used as members for shoe soles are required to have mechanical strength, durability, and resilience that can withstand use, in addition to being lightweight and being difficult to deform even after long-term use. In response to such performance requirements, for example, Patent Document 2 discloses a member for a shoe sole made of a foam of an ethylene-α-olefin copolymer. Further, Patent Document 3 discloses a member for a shoe sole made of a foam of a block copolymer. The foam of Patent Document 3 is obtained by extruding a block copolymer mixed with a foaming agent by an extruder, foaming the block copolymer discharged from a die into foamed particles, and further molding the foamed particles in a mold.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when the sole member receives an impact during landing, it is required to be compressed vertically and deformed, and when the impact is removed, it is required to return to its original shape by its own resilience. However, conventionally, there has been a problem that the faster the sole member deforms, the more likely the resilience is to decrease, and it is difficult to satisfy the performance of the resilience.

[0006] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a sole member capable of exhibiting excellent resilience even when it deforms rapidly.

[0007] The present disclosure can be realized in the following forms.

Means for Solving the Problems

[0008] A sole member comprising a foam using a resin that satisfies the following formula (1). tanδ 10Hz / tanδ 0.1Hz ≦1.0 … Formula (1) tanδ 10Hz : Loss tangent (23°C) which is the ratio of the storage elastic modulus and the loss elastic modulus at a frequency of 10 Hz tanδ 0.1Hz : Loss tangent (23°C) which is the ratio of the storage elastic modulus and the loss elastic modulus at a frequency of 0.1 Hz

Advantages of the Invention

[0009] The sole member of the present disclosure can exhibit excellent resilience even when it deforms rapidly.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] Here, desirable examples of the present disclosure are shown. [2] The foam is a polyolefin resin foam using an olefin block copolymer having an MFR (measured at 190 ° C and 2.16 kgf) of 0.1 g / 10 min or more and less than 5.0 g / 10 min, and is a member for a shoe sole. [3] A member for a shoe sole having a heat dimensional change rate of -30% or more at a temperature of 100 ° C in accordance with JIS K6767 7.5.2 Method B. [4] A member for a shoe sole having a resilience of 60% or more in accordance with JIS K6400-3:2011. [5] A member for a shoe sole having a compression set of 60% or less in accordance with JIS K6262:2013. Hereinafter, the present disclosure will be described in detail. In this specification, for a description using "~" for a numerical range, unless otherwise specified, the lower limit value and the upper limit value are included. For example, in the description of "10~20", both the lower limit value "10" and the upper limit value "20" are included. That is, "10~20" has the same meaning as "10 or more and 20 or less".

[0012] <Form of the member for shoe sole> Shoe soles such as sports shoes used for walking, jogging, and running are provided with an outsole, a midsole, and an insole. The outsole is the part having the ground contact surface of the shoe. The insole is the part for lining. The midsole is provided between the outsole and the insole and is the part that alleviates the impact at the time of landing. In the present embodiment, the midsole is exemplified as the member for the shoe sole.

[0013] The member for the shoe sole is a foam of a resin, and takes either the form of the primary foam 10A shown in FIG. 1 or the thermocompression molded body 10B shown in FIG. 2 which is a secondary foam.

[0014] The primary foam 10A is obtained by foam molding a resin. The thermocompression molded body 10B is obtained by compression molding the primary foam 10A by thermocompression molding or the like. Both the primary foam 10A and the thermocompression molded body 10B can be used as midsole as they are. In particular, the thermocompression molded body 10B has a well - arranged appearance shape and can be said to be preferable.

[0015] The primary foam 10A and the thermocompression molded body 10B each have a sole body 11A, 11B having an outer peripheral shape corresponding to the contour shape of the human sole, and rising portions 12A, 12B rising from the outer peripheral edges of the sole bodies 11A, 11B. The thickness of the sole bodies 11A, 11B gradually decreases from the rear part on the heel side to the front part on the toe side. Since the thermocompression molded body 10B is formed by compressing the primary foam 10A, the thickness of the sole body 11B of the thermocompression molded body 10B is thinner as a whole than the thickness of the sole body 11A of the primary foam 10A.

[0016] Both the primary foam 10A and the thermocompression molded body 10B have a smooth surface shape and are excellent in appearance.

[0017] <Resin composition> The resin composition contained in the above - mentioned primary foam and thermocompression molded body has a resin, preferably an olefin block copolymer, and a foaming agent. That is, the primary foam and the thermocompression molded body can be composed of, for example, a polyolefin - based resin foam obtained by foaming a polyolefin - based resin. In the following description, when there is no need to distinguish between the primary foam and the thermocompression molded body (secondary foam), it is referred to as a polyolefin - based resin foam or a foam. In particular, when the resin does not need to be limited to a polyolefin - based resin, it is referred to as a foam.

[0018] Examples of the olefin block copolymer include those containing a crystalline polymer block (hard block) mainly composed of ethylene and an amorphous polymer block (soft block) in the molecular chain, and each block is connected alternately in two or more, preferably three or more.

[0019] Specifically, examples of the olefin block copolymer include block copolymers having structural units derived from ethylene and structural units derived from at least one α-olefin selected from α-olefins having 4 to 10 carbon atoms.

[0020] Specific examples of the α-olefin having 4 to 10 carbon atoms used in the olefin block copolymer include 1-octene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-decene, and α-olefins having a cyclic structure. Preferably, 1-octene and 1-butene can be used.

[0021] The content of the structural unit derived from at least one α-olefin selected from α-olefins having 4 to 10 carbon atoms contained in the olefin block copolymer is preferably 1 to 49% by weight, more preferably 1 to 30% by weight, and still more preferably 1 to 20% by weight (assuming the total weight of the olefin block copolymer is 100% by weight).

[0022] Specific examples of the olefin block copolymer include ethylene-1-octene copolymers, ethylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-1-decene copolymers, ethylene-(3-methyl-1-butene) copolymers, and copolymers of ethylene and α-olefins having a cyclic structure.

[0023] From the viewpoint of improving moldability and processability, the MFR of the olefin block copolymer measured at 190 °C and 2.16 kgf is preferably 0.1 g / 10 min to 15.0 g / 10 min, and more preferably 0.1 g / 10 min or more and less than 5.0 g / 10 min. Note that this MFR is the value of the olefin block copolymer before crosslinking described later.

[0024] The olefin block copolymer may be used alone, or two or more kinds having different compositions and molecular weights may be combined and used. For example, 10 to 90 parts by weight, preferably 40 to 80 parts by weight of an olefin block copolymer having an MFR (190 ° C, 2.16 kgf) of 0.1 g / 10 min or more and less than 5.0 g / 10 min, and an MFR (190 ° C, 2.16 kgf) of 5.0 g / 10 min to 15.0 g / 10 min. A mixture consisting of 10 to 90 parts by weight, preferably 20 to 60 parts by weight of an olefin block copolymer (the total amount of both olefin block copolymers is 100 parts by weight) can be preferably used.

[0025] Examples of the olefin block copolymer include INFUSE (trademark) manufactured by The Dow Chemical Company Japan Limited. INFUSE (trademark) manufactured by The Dow Chemical Company Japan Limited is commercially available in different grades distinguishable based on MFR (melt flow rate), hardness, density, etc., and these can be used alone or in combination of two or more.

[0026] The foaming agent that causes foaming in the resin composition of the present disclosure is not particularly limited, and a thermal decomposition type that decomposes by heating to generate gas can be used.

[0027] For example, as the foaming agent, azodicarbonamide (ADCA), 2,2'-azobisisobutyronitrile, diazoaminobenzene, benzenesulfonyl hydrazide, benzene-1,3-sulfonyl hydrazide, diphenyl oxide-4,4'-disulfonyl hydrazide, 4,4'-oxybisbenzenesulfonyl hydrazide, paratoluenesulfonyl hydrazide, N,N'-dinitrosopentamethylenetetramine, N,N'-dinitroso-N,N'-dimethylphthalamide, terephthalic azide, p-t-butylbenzene azide, sodium bicarbonate, ammonium bicarbonate, etc. can be used. In particular, azodicarbonamide and 4,4'-oxybisbenzenesulfonyl hydrazide can be preferably used. The addition amount of the foaming agent is preferably 1 to 20 parts by weight, particularly preferably 3 to 8 parts by weight, and more preferably 4 to 7 parts by weight, based on 100 parts by weight of the olefin block copolymer.

[0028] The resin composition of the present disclosure can include a crosslinking agent for crosslinking the resin, if necessary. As the crosslinking agent, known ones that are usually used can be used. For example, as the crosslinking agent, organic peroxides such as dicumyl peroxide (DCP), 2,5-dimethyl-2,5-bis-tert-butylperoxyhexane, and 1,3-bis-tert-peroxy-isopropylbenzene can be mentioned. The compounding amount of the crosslinking agent is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the olefin block copolymer.

[0029] Furthermore, other additives can be added to the resin composition, if necessary. The other additives are not particularly limited, and examples include heavy calcium carbonate, calcium carbonate, diatomaceous earth, barium sulfate, aluminum hydroxide, aluminum oxide, lead oxide, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, barium stearate, zinc stearate, etc. These can be used alone or in combination of two or more.

[0030] The resin constituting the foam preferably satisfies the following formula in terms of the ratio of the loss tangent (tanδ = G" / G'), which is the ratio of the loss elastic modulus (G") to the storage elastic modulus (G'), measured at a frequency of 10 Hz and a frequency of 0.1 Hz in a dynamic viscoelasticity test using the loss tangent as an index and measured in accordance with JIS K7244 under the following measurement conditions. tanδ 10Hz / tanδ 0.1Hz ≦1.0 (Measurement conditions) Viscoelasticity: ARES-G2 TA Instruments Frequency dependence: 0.01 - 79 Hz Temperature: 23°C Mode: Torsion mode Strain: 1.0%

[0031] The storage elastic modulus (G') is a parameter representing the elastic term of the foam and can be regarded as the ability to store the applied deformation energy, etc. as elastic energy. The loss elastic modulus (G") is a parameter representing the viscous term of the foam and can be regarded as the ability to dissipate the applied deformation energy, etc. as internal friction, etc. inside the foam as dissipated energy.

[0032] Ordinary elastomer resins such as ethylene-vinyl acetate copolymer (EVA) and ethylene-octene copolymer (EOR) tend to have a large loss elastic modulus (G") and a large tanδ value at high frequencies (= during rapid deformation). Generally, it is considered that the greater the tanδ value, the greater the energy loss (= the decrease in rebound elasticity).

[0033] On the other hand, compared with the above-mentioned ordinary elastomer resins, olefin block copolymers tend to have less increase in the loss modulus (G") at high frequencies and can maintain a low tanδ value. For this reason, a polyolefin-based resin foam using an olefin block copolymer that satisfies the above formula (tanδ ratio @ 10 Hz / 0.1 Hz ≤ 1.0) can exhibit excellent resilience even under rapid deformation. Examples of olefin block copolymers that satisfy the above formula include "INFUSE D9100" and "INFUSE D9500" manufactured by The Dow Chemical Company Japan Limited.

[0034] If the foam can satisfy the above formula, it may be composed of resins other than olefin block copolymers, such as elastomers such as random copolymers and graft copolymers, and thermoplastic resins.

[0035] <Manufacturing method of foam> First, the manufacturing method of the primary foam will be described. Add crosslinking agents, foaming agents, and additives such as fillers and auxiliaries that may be required as appropriate to resins such as olefin block copolymers, and supply them to a kneading device such as an extruder, a Banbury mixer, or a roll. Knead at a temperature higher than the melting point of the resin and lower than the decomposition temperature of the foaming agent to obtain resin pellets. Subsequently, fill the resin pellets into a mold, seal them, and heat them for a predetermined time under pressure (heat at a temperature higher than the decomposition temperature of the foaming agent). In this way, the crosslinking of the crosslinking agent and the decomposition of the foaming agent proceed, and then, by opening the mold and releasing the pressure, a primary foam made of a resin such as a crosslinked polyolefin-based resin is obtained. Note that the shape of the resin before being put into the mold is not limited to resin pellets and may be in the form of an ingot. Alternatively, as another method, the molten resin is injected into the molding space of the mold and filled, heated for a predetermined time under pressure (heated at a temperature equal to or higher than the decomposition temperature of the foaming agent), and then the volume of the molding space is expanded and depressurized by the retraction (core back) of the movable mold or the like, and the resin is foamed by the pressure drop to obtain a primary foam. When expanding the volume of the molding space, the moving speed of the movable mold can be adjusted, in other words, the depressurization speed can be adjusted, so that the variation in the bubbles generated in the resin composition can be suppressed.

[0036] The thermocompression molded body is obtained by compressing the primary foam in the direction of reducing the thickness in a heated state for a predetermined time and then cooling it. The thermocompression molded body obtained by this thermocompression molding, in addition to having a smaller thickness compared to the primary foam, has a higher density and hardness, and an improvement in resilience can be expected. Also, it is considered that the thermal dimensional change rate and the compression set are reduced by the thermocompression molding.

[0037] <Properties of the foam> The thermocompression molded body of the foam has a resilience of 60% or more, preferably 65% or more, and more preferably 70% or more, measured in accordance with JIS K6400-3:2011. If the resilience is within the above range, a foam with high resilience can be obtained.

[0038] The thermocompression molded body of the foam has an Asker C hardness of 20 or more, more preferably 22 or more, measured at 23°C in accordance with the "Spring Hardness Test Type C Test Method" of JIS K7312. If the Asker C hardness is within the above range, it can be expected to exhibit appropriate resilience.

[0039] The primary foam has a thermal dimensional change rate of -30% or more, preferably -20% or more, and more preferably -10% or more, measured in accordance with Method 7.5.2 B of JIS K6767:1999 (the temperature is 100°C). If the thermal dimensional change rate is within the above range, the dimensional change at high temperatures is small, and a foam with excellent heat resistance can be obtained. Note that the thermal dimensional change rate described in the above JIS standard is calculated by the following formula. Rate of change in pressurized dimension (%) = (Dimension after heating - Dimension before heating) / Dimension before heating × 100 Therefore, the smaller the absolute value of the negative (-) numerical value, the smaller the rate of change in heated dimension, which means it is difficult to shrink, so it can be said that the heat resistance is excellent.

[0040] The foam has a compression set of 60% or less, preferably 55% or less, under the following measurement conditions in accordance with JIS K6262:2013. If the compression set is within the above range, the foam can have excellent shape recoverability.

[0041] (Measurement conditions for compression set) Measure the pre-test thickness h0 of the measurement sample left standing for 3 hours in an environment of temperature 23 ± 2°C and humidity 50 ± 10%. Next, compress the measurement sample by 50% with respect to the pre-test thickness h0, and put the compression device incorporating the measurement sample into a thermo-hygrostat previously maintained at a temperature of 50°C, and let it stand for 6 hours. At this time, measure the thickness h2 of the spacer used (50% of the pre-test thickness h0 of the measurement sample). After 6 hours have elapsed in the compressed state, take out the compression device from the thermo-hygrostat, release the compressed state, and measure the post-test thickness h1 of the measurement sample 30 ± 3 minutes later in an environment of temperature 23 ± 2°C and humidity 50 ± 10%. The compression set (%) is calculated by the following formula. Compression set (%) = [(h0 - h1) / (h0 - h2)] × 100

[0042] The primary foam has an apparent density measured in accordance with JIS K 6767 of 50 to 130 kg / m 3 and preferably 60 to 115 kg / m 3 and more preferably 70 to 100 kg / m 3 is. The thermocompression molded body has an apparent density measured in accordance with JIS K 6767 of 80 to 170 kg / m 3 and preferably 90 to 150 kg / m 3 and more preferably 100 to 130 kg / m 3 is. If the apparent density is within the above range, the shock absorbability can be improved.

Example

[0043] <Fabrication of Foam> (Example 1) 100 parts by weight of “INFUSE D9000” (Polyolefin Resin 1) manufactured by The Dow Chemical Company Japan Limited, which is a polyolefin resin with MFR of 0.5 g / 10 min (190 °C, 2.16 kgf), Shore A hardness of 71, density of 877 kg / m 3 3, melting point of 120 °C, 5 parts by weight of Vinol AC #3 (ADCA: azodicarbonamide) manufactured by Yonghe Chemical Industry Co., Ltd. as a foaming agent, 1 part by weight of Kayacumyl D (DCP: dicumyl peroxide) manufactured by Kayaku Akzo Co., Ltd. as a crosslinking agent, 2 parts by weight of two types of zinc oxide as a foaming aid, and 0.5 part by weight of zinc stearate (trade name: Zinc Stearate N, manufactured by Tanan Chemical Industry Co., Ltd.) were blended. The blend was supplied to a 75 L pressure kneader, melted by self-heating, kneaded at 122 °C, and a foamable resin composition was obtained. This foamable resin composition was filled into a mold (depth 50 × 600 × 1200 mm), sealed, heated at 153 °C for 40 minutes under a pressurized state, and then depressurized (pressure removed) to open the mold to obtain the primary foam of Example 1 by one-step pressurized foaming.

[0044] The primary foam obtained above, with a length of 200 mm, width of 200 mm, and thickness of 26 mm, was placed in the upper and lower molds, clamped, compression molded at 150 °C for 10 minutes, further cooled at 30 °C for 10 minutes, and the mold was opened to obtain a thermocompression molded body of Example 1 with a length of 200 mm, width of 200 mm, and thickness of 20 mm.

[0045] (Example 2) The polyolefin resin was changed to “INFUSE D9100” (Polyolefin Resin 2) with MFR of 1.0 g / 10 min (190 °C, 2.16 kgf), Shore A hardness of 75, density of 0.877 g / cm 3 3, and melting point of 120 °C. Otherwise, the primary foam and thermocompression molded body of Example 2 were obtained in the same manner as in Example 1.

[0046] (Example 3) The polyolefin resin was made into a mixture of 70 parts by weight of "INFUSE D9100" and 30 parts by weight of "INFUSE D9500" (polyolefin resin 3) with an MFR of 5.0 g / 10 min (190 °C, 2.16 kgf), a Shore A hardness of 69, and a density of 0.877 g / cm 3 The primary foams and thermocompression molded articles of Example 3 were obtained in the same manner as in Example 1, except that the above mixture was used.

[0047] (Example 4) The polyolefin resin was made into a mixture of 70 parts by weight of "INFUSE D9100" and 30 parts by weight of "INFUSE D9500" with an MFR of 5.0 g / 10 min (190 °C, 2.16 kgf), a Shore A hardness of 69, and a density of 0.877 g / cm 3 The primary foams and thermocompression molded articles of Example 4 were obtained in the same manner as in Example 1, except that the addition amount of Vinol AC#3 (ADCA: azodicarbonamide), which is a foaming agent, added to 100 parts by weight of the mixture was 6 parts by weight, and 30 parts by weight of calcium carbonate was further added as a filler.

[0048] (Example 5) The primary foams and thermocompression molded articles of Example 5 were obtained in the same manner as in Example 1, except that the polyolefin resin was made into a mixture of 70 parts by weight of "INFUSE D9100" and 30 parts by weight of "INFUSE D9500", and the addition amount of Vinol AC#3 (ADCA: azodicarbonamide), which is a foaming agent, added to 100 parts by weight of the mixture was 6 parts by weight.

[0049] (Example 6) The primary foams and thermocompression molded articles of Example 6 were obtained in the same manner as in Example 1, except that the polyolefin resin was made into a mixture of 50 parts by weight of "INFUSE D9100" and 50 parts by weight of "INFUSE D9500".

[0050] (Comparative Example 1) A primary foam and a thermocompression molded body of Comparative Example 1 were obtained in the same manner as in Example 1, except that the polyolefin resin was ULTRASEN (trademark) 640 (ethylene-vinyl acetate copolymer, vinyl acetate content: 25% by mass) (Polyolefin resin 4) manufactured by Tosoh Corporation.

[0051] (Comparative Example 2) A primary foam and a thermocompression molded body of Comparative Example 2 were obtained in the same manner as in Example 1, except that the polyolefin resin was ULTRASEN 636 (ethylene-vinyl acetate copolymer, vinyl acetate content: 19% by mass) (Polyolefin resin 5) manufactured by Tosoh Corporation, and 30 parts by weight of calcium carbonate was added as a filler.

[0052] (Comparative Example 3) A primary foam and a thermocompression molded body of Comparative Example 3 were obtained in the same manner as in Example 1, except that the polyolefin resin was ENGAGE (trademark) 8003 (ethylene-1-octene random copolymer, density: 0.885 g / cm 3 , melting point: 77°C, MFR: 1.0 g / 10 min) (Polyolefin resin 6) manufactured by Dow Chemical Japan Co., Ltd.

[0053] (Comparative Example 4) A primary foam and a thermocompression molded body of Comparative Example 4 were obtained in the same manner as in Example 1, except that the polyolefin resin was TUFMER (trademark) A4090S (ethylene-1-butene random copolymer, density: 0.893 g / cm 3 , melting point: 82°C, MFR: 3.6 g / 10 min) (Polyolefin resin 7) manufactured by Mitsui Chemicals, Inc.

[0054] The formulations and physical properties of each example are shown in Table 1. Regarding the physical properties of each example, the density and the heating dimensional change rate at 100°C were measured for the primary foam, and the density, Asker C hardness, rebound resilience, and compression set (C / S@50°C, 50%, 6 h) were measured for the thermocompression molded body. The measurement conditions for the heating dimensional change rate, Asker C hardness, rebound resilience, and compression set are as described above. Also, the dynamic viscoelasticity of the polyolefin resin of each example was measured and calculated by the aforementioned "tanδ ratio @10 Hz / 0.1 Hz".

[0055]

Table 1

[0056] Similarly, the formulations and physical properties of each comparative example are shown in Table 2.

[0057]

Table 2

[0058] The heating dimensional change rate of the primary foams of Comparative Examples 1 to 4 was less than -30%. That is, the absolute value of the negative (-) numerical value was greater than "30". On the other hand, the heating dimensional change rate of the primary foams of Examples 1 to 6 was -10% or more. That is, the absolute value of the negative (-) numerical value was "10" or less. Therefore, the sole member of the present disclosure can have a small heating dimensional change rate, excellent heat resistance, and be less likely to deteriorate even in a high-temperature environment in summer.

[0059] The resilience of the thermocompression-molded articles of Examples 1 to 6 was 60% or more, and all showed higher values than the resilience of the thermocompression-molded articles of Comparative Examples 1 to 4. In particular, the resilience of the thermocompression-molded articles of Examples 3 to 6, in which two types of olefin block copolymers were combined, was 65% or more, and in the case of the thermocompression-molded articles of Examples 3 to 5, it was 70% or more. Therefore, the sole member of the present disclosure has high resilience and can improve the supportability at the time of kicking.

[0060] The compression set of the thermocompression-molded articles of Comparative Examples 1 to 4 exceeded 60%. On the other hand, the compression set of the thermocompression-molded articles of Examples 1 to 6 was 60% or less. Therefore, it can be said that the sole member of the present disclosure is excellent in the resilience to compression deformation. In addition, the resins used in Comparative Examples 1 to 4 have a tanδ ratio @ 10 Hz / 0.1 Hz ≥ 1.0. In contrast, the olefin block copolymers used in Examples 1 to 6 have a tanδ ratio @ 10 Hz / 0.1 Hz ≤ 1.0, and further a tanδ ratio @ 10 Hz / 0.1 Hz ≤ 0.8. Therefore, it can be said that the sole member of the present disclosure can exhibit excellent resilience even at a high deformation speed, and it is difficult for the resilience to decrease due to an increase in the deformation speed.

[0061] Furthermore, the sole member of the present disclosure has a smooth appearance with almost no looseness on the surface for both the primary foam and the thermocompression molded body.

[0062] As described above, the sole member of the present disclosure is excellent in lightness and heat resistance, has high resilience, and has mechanical strength that can withstand long-term use, and is excellent in durability. Furthermore, the sole member of the present disclosure is also excellent in moldability and surface smoothness. It should be noted that the above-described embodiments disclosed this time are illustrative in all respects, and the present invention is not limited to the above-described embodiments. For example, the sole member is not limited to the midsole.

Explanation of Reference Numerals

[0063] 10A…Primary foam 10B…Thermocompression molded body 11A, 11B…Sole body 12A, 12B…Upright portion

Claims

1. A foam body made of a resin satisfying the following formula (1), wherein the foam body is a polyolefin resin foam body using an olefin block copolymer having an MFR (measured at 190°C and 2.16 kgf) of 0.1 g / 10 min or more and less than 5.0 g / 10 min, and the foam body is a member for a shoe sole, which is made by using 40 to 80 parts by weight of an olefin block copolymer having an MFR (190°C, 2.16 kgf) of 0.1 g / 10 min or more and less than 5.0 g / 10 min and 20 to 60 parts by weight of an olefin block copolymer having an MFR (190°C, 2.16 kgf) of 5.0 g / 10 min to 15.0 g / 10 min. tanδ １０Ｈｚ / tanδ ０．１Ｈｚ ≤1.0... Equation (1) tanδ １０Ｈｚ : Loss tangent (23°C), which is the ratio of the storage elastic modulus to the loss elastic modulus at a frequency of 10 Hz tanδ ０．１Ｈｚ : Loss tangent (23 °C), which is the ratio of the storage elastic modulus to the loss elastic modulus at a frequency of 0.1 Hz

2. The member for a shoe sole according to claim 1, wherein, in accordance with JIS K6767 7.5.2 Method B, the rate of change in heated dimension at a temperature of 100°C is -30% or more.

3. The member for a shoe sole according to any one of claims 1 to 2, wherein the resilience in accordance with JIS K6400-3:2011 is 60% or more.

4. The member for a shoe sole according to any one of claims 1 to 3, wherein the compression set in accordance with JIS K6262:2013 is 60% or less.

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