WO2018025332A1 - Cushioning composition for footwear and cushioning member for footwear - Google Patents

Abstract

Provided are: a cushioning composition for footwear which includes a lightweight styrene-based thermoplastic elastomer and forms cushioning members that not only have excellent adhesiveness (peel strength) but also have low hardness and excellent mechanical strength (in particular, tensile strength); and a cushioning member for footwear which is obtained from the cushioning composition. The cushioning composition for footwear comprises a styrene-based thermoplastic elastomer (A) and a softener (B), wherein the styrene-based thermoplastic elastomer (A) comprises: a block copolymer (a1) obtained by hydrogenating a block copolymer X-Y-X; and a modified styrene/ethylene/butylene/styrene block copolymer (a2). The block copolymer X-Y-X comprises: blocks X located at both terminals and each comprising a styrene polymer block; and an intermediate block Y comprising a styrene/butadiene copolymer block. The block copolymer (a2) is an amine-modified block copolymer or a maleic-anhydride-modified block copolymer. The block copolymers a1 and a2 have been blended so that a2/(a1+a2)=0.25-0.95 by weight. The styrene-based thermoplastic elastomer (A) and the softener (B) have been blended so that B/(A+B) = 0.5 to 0.7 by weight.

Description

Footwear cushioning composition and footwear cushioning member

The present invention relates to a cushioning member for footwear such as a cushioning member incorporated in a shoe sole such as an outsole or a midsole or a cushioning member applied to an insole of a shoe, and a cushioning composition for footwear forming the same.

In recent years, in a shoe design mainly in a field where functionality such as sports shoes, walking shoes, and comfort shoes is required, a cushioning member having excellent cushioning properties has been incorporated into a sole formed of resin or the like. The buffer member is required to be lightweight so as not to hinder the movement of the user. In addition, since this type of cushioning member is incorporated into the sole in such a manner that it can be visually recognized from the outside so that its functionality can be appealed to consumers, high design properties such as a transparent appearance are often required. Therefore, various buffer members made of a styrene thermoplastic elastomer having low specific gravity and transparency have been proposed (Patent Documents 1 and 2).

The buffer member is made of a flexible (low hardness) viscoelastic body or rubber elastic body exhibiting excellent buffering properties, and is attached to a sole member having rubber elasticity made of EVA or the like and is applied to the sole. Both the buffer member and the sole member are subjected to stress deformation due to impact or stress. At that time, since the bonding surfaces of the buffer member and the sole member are also stretched and deformed, it is important to maintain the adhesion state between the two bonding surfaces and to ensure the mechanical strength that can withstand rapid stretching deformation. Thus, in order to ensure the function and quality of the shoe sole, extremely reliable adhesion is required. From the viewpoint of adhesiveness, there is room for improvement in the buffer member formed from the styrene-based thermoplastic elastomer described in Patent Documents 1 and 2.

Therefore, in order to solve the above problems, as a composition for forming a buffer member having excellent adhesiveness, one or two kinds of modified S-EB-S (styrene-ethylene-butylene-styrene block copolymer) and A styrenic thermoplastic elastomer composition composed of a rubber softener has been proposed (Patent Document 3).

Japanese Patent Laid-Open No. 2003-12886 JP 2000-281850 A JP 2012-36300 A

In the styrene thermoplastic elastomer composition described in Document 3, a modified S-EB-S block copolymer is used as the styrene thermoplastic elastomer. Therefore, in order to obtain a buffer member excellent in flexibility that contributes to the buffer performance, it is necessary to adjust the blending amount of the rubber softener. However, in order to obtain a cushioning member with lower hardness and excellent flexibility, increasing the blending amount of the rubber softener such as paraffin oil may reduce the adhesiveness of the cushioning member and reduce the mechanical strength. There was room for improvement.

The present invention has been devised in view of the above-mentioned points, and its purpose is composed of a lightweight styrene-based thermoplastic elastomer, which is excellent in adhesiveness (peeling adhesive strength) and has low hardness and mechanical strength (particularly tearing). An object of the present invention is to provide a cushioning composition for footwear that forms a cushioning member excellent in strength) and a cushioning member for footwear using the same.

In order to solve the above problems, the buffer composition for footwear of the present invention is a composition containing a styrene-based thermoplastic elastomer (A) and a softening agent (B), and the styrene-based thermoplastic elastomer (A) is: A block copolymer (a1) obtained by hydrogenating a block copolymer XYX comprising both terminal blocks X comprising a styrene polymer block and an intermediate block Y comprising a copolymer block of styrene and butadiene. And a modified styrene-ethylene-butylene-styrene block copolymer (a2), and the block copolymer of a2 is an amine-modified block copolymer or a maleic anhydride-modified block copolymer, and a1 And the blend ratio of the block copolymer of a2 is a2 / (a1 + a2) = 0.25 to 0.95 by weight, and the styrene-based thermoplastic elastomer The mixing ratio of the Tomah (A) and the softener (B) is, in weight ratio, B / (A + B) = 0.5 to 0.7.

As the styrenic thermoplastic elastomer (A), a block copolymer XYX comprising both terminal blocks X composed of styrene polymer blocks and an intermediate block Y composed of a copolymer block of styrene and butadiene is hydrogenated. Use of the added block copolymer (a1) in combination with the amine-modified or maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer (a2) contributes to buffer performance. The composition which forms the buffer member which has the outstanding softness | flexibility, the outstanding mechanical strength, and adhesiveness is obtained. Further, the blending ratio of each block copolymer of the styrenic thermoplastic elastomer (A) by weight ratio is a2 / (a1 + a2) = 0.25 to 0.95, so that excellent flexibility, adhesion and machine A composition for forming a molded body having strength is obtained. Further, by setting the blending ratio of the styrene thermoplastic elastomer (A) and the softening agent (B) to B / (A + B) = 0.5 to 0.7, excellent flexibility can be obtained, adhesiveness, A composition for forming a molded body having mechanical strength is obtained.

The block copolymer a1 in the footwear buffer composition of the present invention is preferably an acid-modified one. Thereby, the composition which forms the buffer member which has the outstanding adhesiveness, a softness | flexibility, and mechanical strength is obtained.

In the footwear buffer composition of the present invention, the softener (component B) is preferably a paraffinic oil having a molecular weight of 400 to 1200. Thereby, the suitable structural component which can improve the fluidity | liquidity at the time of thermoforming, such as mechanical strength, adhesiveness, and injection molding, is selected.

Further, the footwear buffer composition of the present invention preferably further contains hollow body fine particles. Thereby, the composition which can form a more lightweight buffer member is obtained.

The footwear buffer composition of the present invention preferably has a molded body hardness at 23 ± 2 ° C. of Asker C30-50 (SRIS 0101 standard). Thereby, the buffer member which has the outstanding buffer property can be formed.

The footwear cushioning material of the present invention comprises a block copolymer XYX comprising both end blocks X comprising styrene polymer blocks, and an intermediate block Y comprising styrene / butadiene copolymer blocks. A styrene-based thermoplastic elastomer (A) comprising a hydrogenated block copolymer (a1) and a modified styrene-ethylene-butylene-styrene block copolymer (a2), a softener (B), and a2 The block copolymer is an amine-modified block copolymer or a maleic anhydride-modified block copolymer, and the blend ratio of the a1 and a2 block copolymers is a2 / (a1 + a2) = 0. The blending ratio of the styrenic thermoplastic elastomer (A) and the softening agent (B) is B / (A + B) = 0.5 to 0.00. Molding the footwear cushioning composition is formed by.

As the styrenic thermoplastic elastomer (A) in the footwear buffer composition forming the footwear cushioning member, both terminal blocks X made of a styrene polymer block, and an intermediate block Y made of a copolymer block of styrene and butadiene, And a block copolymer (a1) obtained by hydrogenating a block copolymer XYX comprising: and an amine-modified or maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer (a2). ) Is used in combination, it is possible to obtain a buffer member having both excellent flexibility contributing to buffer performance and excellent mechanical strength and adhesiveness. Further, the blending ratio of each block copolymer of the styrenic thermoplastic elastomer (A) is a2 / (a1 + a2) = 0.25 to 0.95 in terms of weight ratio, so that excellent adhesiveness, flexibility and A buffer member having mechanical strength is obtained. Further, by setting the blending ratio of the styrene thermoplastic elastomer (A) and the softening agent (B) to B / (A + B) = 0.5 to 0.7, excellent flexibility can be obtained, adhesiveness, A buffer member having mechanical strength can be obtained.

In addition, the block copolymer a1 in the footwear buffer composition of the footwear cushioning member of the present invention is preferably an acid-modified one. Thereby, the buffer member which has the outstanding adhesiveness, a softness | flexibility, and mechanical strength is obtained.

Further, the footwear cushioning composition of the footwear cushioning material of the present invention further contains hollow body fine particles, and preferably has a plurality of closed cells inside. Thereby, the shock absorbing member for footwear can be further reduced in weight.

In the footwear of the present invention, it is also preferred that the foot cushioning member is disposed on the insole or midsole. Thereby, the outstanding buffer property can be provided to a sole.

Further, the method for producing a footwear buffer composition of the present invention is a preparatory step in which the softening agent (B) is previously dispersed in at least one component of the block copolymers a1 and a2 in the footwear buffer composition described above. It has the kneading | mixing process which mixes the block process of a1 and a2 which passed through the dispersion | distribution process and the preliminary dispersion | distribution process, and heat-kneads. Thereby, since the constituent components are easily dispersed uniformly in the kneading step, a composition that forms a molded body having excellent flexibility and excellent adhesion that contributes to buffer performance and also having mechanical strength is obtained.

Further, in the method for producing a footwear buffer composition of the present invention, the softener (B) is dispersed in each of the components of the block copolymers a1 and a2 in the above preliminary dispersion step, and the same temperature. It is preferable to increase the blending amount of the softening agent (B) per unit weight as the component has a higher melt viscosity. Thereby, each constituent component is more uniformly kneaded and dispersed in the mixing step, so that a composition with more stable performance and physical properties described above can be obtained.

In the method for producing a footwear buffer composition of the present invention, the softening agent (B) is dispersed in each of the components of the block copolymers a1 and a2 in the preliminary dispersion step. And the dispersion of the softener (B) with respect to each component of the block copolymer of a2 is the melt viscosity (melt mass flow rate, MFR: JIS K7210-1 method 190) of each component in the state where the softener (B) is dispersed. It is preferable to adjust the blending amount of the softening agent (B) so that the difference in melt viscosity value of each component is 150 (g / 10 min) or less. As a result, the difference in melt viscosity between a1 and a2 that has absorbed the softener (B) is reduced, and even more uniformly kneaded and dispersed during heating and kneading. can get.

According to the present invention, in a composition comprising a styrenic thermoplastic elastomer, a buffer composition for footwear which forms a molded article having excellent flexibility, mechanical strength and adhesiveness, which are usually difficult physical properties. And a buffer member is obtained.
In addition, according to the method for producing a footwear buffer composition of the present invention, since the constituent components are uniformly kneaded and dispersed in the kneading step, excellent physical properties such as flexibility, adhesiveness and mechanical strength can be stably obtained. A composition for forming a molded body is obtained.

As an embodiment of the foot cushioning member of the present invention, (A) a perspective view schematically showing a sports shoe in which the foot cushioning member is incorporated, and (B) a configuration of the footwear cushioning member incorporated therein is schematically shown. FIG. 2 is a perspective view, a plan view, and (C) a partial cross-sectional view taken along the line DD of the plan view of FIG. It is sectional drawing which shows roughly the one part layer structure in one Embodiment of the buffer member for footwear of this invention. It is the (A) top view and (B) front view which show roughly the structure of the test piece produced for the peeling adhesive strength test of the buffer member for footwear in an Example and a comparative example. It is a figure explaining the method of the peeling adhesive strength test done using the test piece of FIG.

The styrenic thermoplastic elastomer (A) constituting the footwear buffer composition of the present invention will be described. The styrenic thermoplastic elastomer (A) is obtained by hydrogenating a block copolymer XYX consisting of a terminal block X consisting of a styrene polymer block and an intermediate block Y consisting of a copolymer block of styrene and butadiene. It contains a block copolymer (a1) added and two block copolymers, a modified styrene-ethylene-butylene-styrene block copolymer (a2).

The block copolymer a1 is a hydrogenated block copolymer obtained by hydrogenating a triblock copolymer represented by the general formula XYX as described above. Here, X is a styrene polymer block, and Y is a copolymer block of styrene and butadiene. When the intermediate block Y composed of a copolymer block of styrene and butadiene is hydrogenated, the styrene portion is not changed, but the butadiene portion is changed to hydrogenated butadiene represented by ethylene-butylene. Therefore, the block copolymer a1 is specifically represented by the formula S-EB / SS (S: styrene, EB: hydrogenated butadiene), and the intermediate block has styrene dispersed in the hydrogenated butadiene (randomly). Polymerized). The styrene and butadiene in the intermediate block Y are preferably polymerized randomly. The distribution of styrene and butadiene in the intermediate block Y is relatively high in butadiene in the terminal region adjacent to the terminal block X (styrene polymer block) and styrene in the region not adjacent to the terminal block X (styrene polymer block). It is preferable that it is comprised so that relatively many may be included. Further, the block copolymer a1 includes an acid-modified modified product, and specifically, a maleic acid-modified product containing a maleic anhydride graft is preferably used. The weight average molecular weight Mw of the block copolymer (a1) is preferably 50000 or more from the viewpoint of mechanical strength, and preferably 270000 or less from the viewpoint of adhesiveness and fluidity during molding, that is, 50000 ˜270,000 is preferred. By setting the weight average molecular weight Mw of the block copolymer (a1) within this range, excellent adhesiveness, that is, an adhesive state with an adhesive with another member is sufficiently maintained, and peeling of the adhesive state occurs. It is possible to obtain a composition that can form a difficult-to-form molded body and can form a cushioning member having flexibility, mechanical strength and lightness. Moreover, the fluidity | liquidity at the time of heat molding, such as injection molding, is also favorable, and manufacture of a molded article (buffer member) can also be made easy. In addition, the molecular weight in this invention is the weight average molecular weight Mw, and means the value measured by the gel permeation chromatography (GPC) method. The styrene content of the block copolymer (a1) is preferably 20 to 60% by weight from the viewpoint of improving the mechanical strength such as the adhesiveness and tear strength of the molded product (buffer member). More preferably, it is ˜60% by weight. When the styrene content is less than 20% by weight, the adhesion and mechanical strength are insufficient, and when it exceeds 60% by weight, the flexibility is lowered. Therefore, by setting the styrene content in this range, a composition having excellent adhesion and mechanical strength and excellent flexibility can be obtained.

As described above, the block copolymer a2 is a modified styrene-ethylene-butylene-styrene block copolymer modified with amine or maleic anhydride, that is, amine-modified S-EB-S or maleic anhydride-modified S-. EB-S is used. This styrene-ethylene-butylene-styrene block copolymer includes a hydrogenated product of a styrene-butadiene-styrene block copolymer. Unlike the block copolymer a1, the intermediate block of the block copolymer a2 is composed only of ethylene-butylene or hydrogenated butadiene. The weight average molecular weight Mw of the block copolymer (a2) is preferably 50000 or more from the viewpoint of mechanical strength, and preferably 270000 or less from the viewpoint of adhesiveness and fluidity during molding, that is, 50000 ˜270,000 is preferred. By setting the weight average molecular weight Mw of the block copolymer (a2) within this range, excellent adhesiveness, that is, an adhesive state with an adhesive with another member is sufficiently maintained, and peeling of the adhesive state occurs. It is possible to obtain a composition that can form a difficult-to-form molded body and can form a cushioning member having flexibility, mechanical strength and lightness. Moreover, the fluidity | liquidity at the time of heat molding, such as injection molding, is also favorable, and manufacture of a molded article (buffer member) can also be made easy. The styrene content of the block copolymer (a2) is preferably 20 to 60% by weight from the viewpoint of improving mechanical strength such as adhesion and tear strength of the molded product (buffer member). When the styrene content is less than 20% by weight, the adhesion and mechanical strength are insufficient, and when it exceeds 60% by weight, the flexibility is lowered. Therefore, by setting the styrene content in this range, a composition having excellent adhesion and mechanical strength and excellent flexibility can be obtained.

As a styrenic thermoplastic elastomer (A), a cushioning composition for footwear that forms a cushioning member having both excellent flexibility, mechanical strength and adhesiveness by using a combination of the above-mentioned block copolymers a1 and a2 Things are obtained. Although it does not specifically limit as a specific example of the block copolymer of a1 and a2, The following products are used suitably. Examples of the block copolymer a1 include Kraton (registered trademark) A1536, A1535, RP6670 (product of Kraton Polymer Japan Co., Ltd.) and the like, and examples of the block copolymer a2 include Tuftec (registered trademark) MP10, M1913 (Asahi Kasei Chemicals). Products).

Furthermore, the blending ratio of the styrenic thermoplastic elastomer (A) constituting the footwear buffer composition of the present invention is the weight ratio of the blending ratios of the block copolymers a1 and a2 from the viewpoint of adhesiveness and mechanical strength. A2 / (a1 + a2) = 0.25 to 0.95, more preferably 0.3 to 0.8, and particularly preferably 0.4 to 0.6. The blending ratio a2 / (a1 + a2) is the blending ratio of the amine-modified S-EB-S (a2) in the styrene-based thermoplastic elastomer (A). If it is less than 0.25, the adhesiveness is inferior. If it exceeds .95, the mechanical strength tends to decrease. Therefore, the composition which forms the molded object excellent in adhesiveness and mechanical strength is ensured, ensuring a softness | flexibility by making the mixture ratio of each block copolymer into said range.

Next, the softener (B) constituting the footwear buffer composition of the present invention will be described. The softener is added mainly for the purpose of imparting flexibility to the composition. Regarding the blending ratio of the softening agent (B), the blending ratio of the softening agent (B) to the sum of the styrene-based thermoplastic elastomer (A) and the softening agent (B) is 0.5 to 0.7 by weight. It is preferable that it is 0.55 to 0.65. When the value of B / (A + B) is less than 0.5, sufficient flexibility cannot be obtained, and when it exceeds 0.7, heat resistance and mechanical strength are lowered and adhesion due to bleeding of the softening agent (bleed) is caused. Decrease. Therefore, by setting the blending ratio of the softener to the above range, flexibility can be adjusted without lowering other physical properties.

In this embodiment, as the softener, for example, process oil such as paraffinic oil, naphthenic oil or aromatic oil, synthetic resin softener such as liquid polybutene or low molecular weight polybutadiene, rosin and the like are used. Of these, paraffinic oil is preferably used among process oils from the viewpoint of transparency of appearance, and paraffinic oil having a weight average molecular weight of 400 to 1200 is particularly preferably used. From the viewpoint of peel adhesion strength and mechanical strength, the weight average molecular weight is preferably 400 or more, and from the viewpoint of fluidity during molding, the weight average molecular weight is preferably 1200 or less. Therefore, by using a paraffinic oil having a weight average molecular weight of 400 to 1200, a composition having better peel adhesion strength, mechanical strength, and flowability during molding can be obtained.

Furthermore, the buffer composition for footwear of the present invention may further contain hollow fine particles. Thereby, the composition which can form a lighter molded object is obtained. Here, the hollow body fine particles refer to fine hollow bodies (microballoons) having a space of about 3 to 300 microns inside the particles. The hollow fine particles are preferably those that thermally expand in a heating and kneading step or the like during production and are dispersed throughout the composition. As the hollow fine particles, organic hollow fine particles that can be deformed by stress together with the footwear buffer composition are preferable. The organic hollow fine particles are organic balloons whose outer shells are mainly made of a thermoplastic resin. In the present invention, organic balloons that thermally expand, particularly when heat-molding a footwear buffer composition, are preferably used. . Specific examples of the thermally expandable organic balloon include EXPANSEL (registered trademark, Nippon Philite Co., Ltd.) and Matsumoto Microsphere (Matsumoto Yushi Seiyaku Co., Ltd.). Moreover, you may use together an inorganic type hollow body fine particle as a strength reinforcement material accompanying weight reduction in the range which does not impair the effect of the buffer composition for footwear of this invention. The inorganic hollow body fine particles are inorganic balloons mainly composed of aluminosilicate. Specific examples thereof include phylite (registered trademark, Nihon Philite Co., Ltd.), senolite (registered trademark, Sakai Industrial Co., Ltd.), cenosphere (registered). Trademark, Sakai Industrial Co., Ltd.) and the like. Moreover, a well-known foaming agent may be added instead of the hollow body fine particles, and the foamed product may be formed by heating and foaming.

Furthermore, the buffer composition for footwear of the present invention may contain the third styrene-based elastomer component (a3), other thermoplastic resin components and additives within the range not impairing the effects of the present invention. is there. Examples of the third styrene elastomer component (a3) include styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS) and high styrene content for the purpose of adding heat resistance and enhancing mechanical strength. An unmodified S-EB-S block copolymer or the like can be applied. The other thermoplastic component is preferably compatible with the footwear buffer composition, and a thermoplastic resin may be appropriately selected according to the properties to be added. Examples of additives include pigments, colorants, lubricants, mold release agents, antioxidants, antibacterial agents, ultraviolet absorbers, light stabilizers, and heat resistance agents. These can be used alone or in combination.

The hardness of the molded article of the buffer composition for footwear of the present invention is preferably 50 or less Asker C (SRIS 0101 standard 23 ° C. ± 2 ° C.). (2 ° C.) 30 to 50 is more preferable. Therefore, the composition of the present invention is useful as a composition for forming a cushioning member for footwear having sufficient flexibility that contributes to cushioning. The hardness is measured using a test piece that has been conditioned for at least 1 hour in a 23 ± 2 ° C. test room (according to JIS K6253-3). Furthermore, the molded article of the footwear buffer composition of the present invention is 2.5 kgf to a shoe material (mainly sole member) bonded with an adhesive for shoe production such as a polyurethane adhesive or an adhesive for chloroprene rubber. / 20 mm or more (JIS K6854-3, in the case of having a primer-treated layer on the adherend surface) and high peel adhesion strength. As a result, even when the footwear cushioning member is bonded to the shoe sole member and incorporated in the shoe sole portion, it can withstand stress deformation during exercise, and high bonding reliability is realized. Further, the molded article of the footwear buffer composition of the present invention exhibits a physical property of tear strength of 6.5 kN / m or more in accordance with JIS K6252-1 B method (angle type test piece without cutting), and is resistant to stress deformation. Hard to damage.

The footwear buffer composition of the present invention is produced by a known resin composition production method. Specifically, as an example, using a melt kneader such as a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or a heating roll, compounding components such as A component and B component are added at a predetermined ratio. It is obtained by heating the compounding components and uniformly kneading each component in a molten state. Although it does not specifically limit as a concrete manufacturing process, The softening agent (B) is used for at least one part of the weighing process which weighs each structural component to a predetermined | prescribed compounding ratio, and the component which comprises a styrene-type thermoplastic elastomer (A). It is preferable to have a pre-dispersing step for absorbing the water and a kneading step for mixing the components constituting the styrene-based thermoplastic elastomer (A) in which the softening agent (B) is absorbed and kneading with heating. As a result, a composition in which each constituent component is more uniformly dispersed during kneading can be obtained. In addition, since the block copolymers a1 and a2 constituting the styrene-based thermoplastic elastomer (A) generally have a higher molecular weight and are difficult to melt, depending on the molecular weight of the block copolymers a1 and a2, It is preferable to adjust the heating temperature. Further, in this preliminary dispersion step, the softening per unit weight is performed in descending order of the melt viscosity at the same temperature for each of the components a1 and a2 which are block copolymers constituting the styrenic thermoplastic elastomer (A). It is preferable to increase the distribution ratio of the agent (B). Thereby, the melt viscosity of a1 component which absorbed softener (B), and a2 component adjoin, and the composition by which each structural component was disperse | distributed more uniformly at the time of kneading | mixing is obtained. Further, in the preliminary dispersion step described above, the softening agent (B) is dispersed in the components a1 and a2 which are block copolymers constituting the styrenic thermoplastic elastomer (A). Regarding the melt mass flow rate (MFR: JIS K7210-1B method, 190 ° C.) of each component in the absorbed state, the difference in MFR value between the component with the highest MFR and the component with the lowest MFR is 150 (g / 10 min) or less. Thus, it is particularly preferable that the distribution amount of the softener (B) is adjusted. As a result, the uniform dispersibility of each component in the kneading step is further improved, the properties such as flexibility, adhesiveness and mechanical strength are excellent, variations in these properties are reduced, and melt moldability is also improved.

The buffer composition for footwear of the present invention can be formed into a pellet, sheet or chip shape by a known method such as injection molding, extrusion molding, hollow molding, compression molding or calendar molding. Further, as will be described in detail below, it is of course possible to mold into various molded bodies.

The footwear cushioning member of the present invention is obtained by molding the footwear cushioning composition into a predetermined shape by the above-described injection molding method or the like. FIG. 1 (A) shows footwear cushioning members 10 and 11 disposed on a heel portion 41 and a side edge portion 42 of a sole portion of a sports shoe 40 as an embodiment of the footwear cushioning member of the present invention. ing. The cushioning member for footwear obtained by the composition of the present invention has a peel adhesion strength of 2.5 kgf / 20 mm or more to other members such as the heel portion 41 of the sole portion (JIS K6854-3, primer treatment on the adherend surface) A layer). Further, the cushioning member for footwear of the present invention exhibits a physical property of tear strength of 6.5 kN / m or more in accordance with JIS K6252-1 B method (angle type test piece without cutting), and is not easily damaged by stress deformation. Therefore, since the foot cushioning members 10 and 11 of the present invention have high adhesion reliability and flexibility and are excellent in tear strength, they are not easily damaged by stress deformation when used as footwear. Moreover, since the hardness of the molded body of the buffer composition for footwear of the present invention is Asker C (SRIS 0101 standard 23 ° C. ± 2 ° C.) 50 or less, the foot cushion member formed by molding the buffer composition for footwear is In particular, when the molded body is made of a cushioning composition for footwear having Asker C30-50, it has an excellent balance between cushioning and resilience, and is useful as a cushioning member for footwear. is there.

The footwear cushioning member of the present invention is used by being bonded to a sole member such as an insole, a midsole or an outsole, and is disposed on the upper side or the lower side of the sole member or embedded in an internal space of the sole member. It can be used in various known modes. Specifically, although not particularly limited, the cushioning member for footwear is used so as to be sandwiched between the insole member and the midsole member, or disposed and used so as to be sandwiched between two layers of the midsole member. Or used so as to be embedded in the internal space of the sole member in which the concave portion is formed. Adhesion between the footwear cushioning member and the various sole members can employ a known method such as a method using an adhesive or heat-melt adhesion.

In order to enhance the adhesion between the foot cushioning member and the sole member of the present invention and to ensure the adhesion reliability, the foot cushioning member and the sole member should be bonded via a primer treatment layer. Is also preferable. The primer-treated layer refers to a layer formed by previously treating the surface of the molded body of the sole member or the footwear buffer composition with a primer agent such as a surface treatment agent. As a result, the footwear cushioning member and the sole member are bonded to each other via the primer treatment layer, so that higher adhesion reliability between the footwear cushioning member and the sole member can be realized. In forming the primer treatment layer on the sole member, a suitable primer agent is applied to a portion of the sole member that contacts the footwear cushioning member and dried. As the primer agent, for example, when the sole member is urethane rubber, an acrylic primer agent or the like is preferably used. The foot buffer composition of the present invention in a molten state is injected into the portion of the sole member where the primer treatment layer is formed, and then cooled, and the foot cushion member is molded (insert molding), thereby interposing the primer treatment layer. Thus, the footwear cushioning member and the sole member can be firmly bonded. On the other hand, as shown in FIG. 1 (C) and FIG. 2, the primer treatment layer 2 can be formed by applying a primer treatment to the surface of the molded article 1 of the footwear buffer composition. The primer treatment applied to the surface of the molded body 1 includes, for example, a primer agent containing a polyol-terminated urethane prepolymer, an isocyanate and a solvent as main components to dissolve the surface of the molded body, and the dissolved components of the molded body A primer-treated layer comprising an inseparable integral layer in which a reaction product of a polyol-terminated urethane prepolymer and an isocyanate and a component of a molded article (footwear buffer composition) 1 are mixed. 2 is preferable (see Japanese Patent No. 563689). Thereby, since the primer treatment layer 2 in which the components of the dissolved molded article (footwear buffer composition) and the reaction product of the primer agent are mixed has reactivity with the adhesive, the primer treatment layer 2 is interposed between the primer treatment layer 2 and the primer treatment layer 2. The molded body 1 and the adhesive can be substantially integrated and firmly bonded.

Further, as shown in FIG. 1, the surface of at least a part of the footwear cushioning member 10, for example, the part 10 a that needs to improve the adhesiveness between the two, the part exposed without being covered by the sole member, etc. As shown in FIG. 1 (C) and FIG. 2, it may be covered with a substantially transparent protective layer 3 formed of a urethane-based coating agent. By covering with the protective layer 3, it is possible to make it difficult to damage the exposed portion of the footwear cushioning member, and to further improve the adhesion to the sole member. The protective layer 3 is formed by applying a urethane-based coating agent to the surface of the molded article 1 of the footwear buffer composition. Examples of the urethane-based coating agent include a photo-curing type and a thermosetting type. A moisture curable type may be mentioned, but a photocurable urethane coating agent that is cured by irradiation with light such as ultraviolet rays is preferably used because it can be cured in a room temperature environment in a short time and has excellent productivity. As the type of reactive urethane of the photo-curing urethane coating agent, known substantially transparent reactive urethanes such as ether urethane, ester urethane, carbonate urethane, polycaprolactone urethane can be applied, especially solvent resistance and flexibility. Carbonate-based urethane is preferable from the viewpoints of heat resistance and hydrolysis resistance. As composition of the photocurable urethane coating agent to which carbonate-based urethane is applied, reactive carbonate-based urethane (c1), photopolymerization initiator (c2), thickener (c3) and water (c4) are contained. . Although it does not specifically limit as reactive carbonate type urethane (c1), For example, the carbonate type urethane etc. which have the polymerizable unsaturated bond obtained by making polycarbonate diol and polyisocyanate react as a raw material are used. As the photopolymerization initiator (c2), known ones can be used and are not particularly limited. For example, acetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, benzophenone, 2-chloro Benzophenone, p, p'-bisdiethylaminobenzophenone, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin n-butyl ether, benzoin dimethyl ketal, thioxanthone, p-isopropyl-α-hydroxyisobutylphenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholino Lopan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6, -trimethylbenzophenone, 4-methylbenzophenone or 2,2-dimethoxy-1,2-diphenylethane Non etc. are mentioned. Of these, hydroxycyclohexyl phenyl ketone is preferred. Further, as the thickener (c3), aliphatic alcohols such as ethanol, glycol, ethylene glycol monoethyl ether, or a combination thereof is preferably used. Further, water (c4) functions as a dispersion medium for c1 to c3, and a photocurable urethane coating agent in the form of an aqueous emulsion is obtained. In addition, when a urethane type coating agent is apply | coated to the surface of at least one part of the molded object 1 of the buffer composition for footwear, and forms the protective layer 3, as shown in FIG.1 (C) and FIG. Although it may apply | coat through the layer 2, you may apply | coat a urethane type coating agent directly on the surface of the molded object 1 of the buffer composition for footwear.

As a blending ratio of each component constituting the photocurable urethane coating agent, from the viewpoint of curability of the photocurable urethane coating agent, the photopolymerization initiator (c2) is blended with the reactive carbonate urethane (c1). The ratio c2 / c1 is 0.01 to 0.1 by weight, and more preferably 0.025 to 0.075. When c2 / c1 is less than 0.01, sufficient curing reaction does not proceed, resulting in curing failure. When it exceeds 0.1, curability is inhibited and curing failure occurs, or odor after curing remains. This is not preferable. In addition, the mixing ratio c4 / c1 of water (c4) to the reactive carbonate urethane (c1) is preferably 1.9 to 3.0, and preferably 2.1 to 2.7. Is more preferable. If c4 / c1 is less than 1.9, the emulsion state of the photocurable urethane coating agent cannot be maintained, so that uniform coating becomes difficult. If it exceeds 3.0, the photocurable urethane coating agent is used. Since the viscosity of the film is too low and is repelled on the coating surface, it becomes difficult to form a uniform coating, and a uniform protective layer cannot be formed. Further, the blending ratio c3 / c1 of the thickener (c3) with respect to the reactive carbonate-based urethane (c1) is a weight from the viewpoint of improving the coatability when forming the protective layer by setting the coating agent to an appropriate viscosity. The ratio is preferably 0.3 to 3.5, and more preferably 0.6 to 1.7.

The footwear cushioning member coated with the primer treatment layer 2 or the protective layer 3 obtained as described above is a shoe material (members) bonded with an adhesive for shoe production such as polyurethane adhesive or chloroprene rubber adhesive. ), A high peel adhesion strength of 2.5 kgf / 20 mm or more (JIS K6854-3) can be exhibited. As a result, even when the footwear cushioning member is bonded to the shoe sole member and incorporated into the shoe sole portion, it can withstand stress deformation during exercise and high adhesion reliability is realized. .

Hereinafter, the present invention will be described in detail using examples. The evaluation method of the footwear buffer composition in the following Examples and Comparative Examples is as follows.

(1) Hardness Using an Asker C durometer (SRIS 0101 standard) conforming to JIS K6253, the hardness of each test piece that had been conditioned for at least 3 hours in a 23 ± 2 ° C. test room was measured. As a test piece, what each shape | molded the buffer composition for footwear in an Example and a comparative example in length 60mm x width 60mm x thickness 12mm was used. Asker C50 or less was judged as good “◯”, and over 50 was judged as inappropriate “x”.

(2) Tear strength (strength)
In accordance with JIS K6252-1 B method, a tensile tester (manufactured by Shimadzu Corporation) was used for five test pieces in which each of the footwear buffer compositions in Examples and Comparative Examples was formed into an angled shape (dumbbell B type) without cutting. Autograph (registered trademark), AT-100N) was used to measure the maximum load value F [N] that leads to fracture at a pulling speed of 500 mm / min, and divided by the thickness t [m] of the test piece to determine the tear strength. Calculated. The average value of the two values sandwiching the median tear strength of the five test pieces was taken as the tear strength (kN / m). The case where the tear strength value was 6.5 kN / m or more was judged as “good”, and the case where it was less than 6.5 kN / m was judged as “poor”.

(3) Peel adhesion strength (adhesion strength)
In accordance with JIS K6854-3, the peel adhesion strength of each test piece was measured. The peel adhesion strength test method will be specifically described with reference to FIGS. FIG. 3 schematically shows the configuration of the sample piece 50, which is schematically composed of a test piece (buffer member of an example or a comparative example) 51, an adhesive urethane piece 52, and an adhesive layer 53. The sample piece 50 shown in FIG. 3 includes (3-1) primer treatment layer / pressure bonding, (3-2) primer treatment layer / insert molding, and (3-3) primer treatment layer / insert molding, which will be described later. These were produced by the following three methods. FIG. 4 illustrates a method for testing the peel adhesion strength of the sample piece 50. As shown in FIGS. 4 (A) and 4 (B), each sample of (3-1) to (3-3) was obtained using a tensile tester (Autograph (registered trademark), AT-100N, manufactured by Shimadzu Corporation). The test piece 51 of the piece 50 and the urethane piece 52 were peeled off, and the peel adhesive strength was measured. In FIG. 4, 54 is a fixed-side tension jig, and 55 is a movable-side tension jig. The load cell was 1 kN (100 kgf), the test speed was 50 mm / min, and the initial gap between the fixed-side tension jig 54 and the movable-side tension jig 55 was 20 mm.

(3-1) Sample piece: Primer-treated layer / Pressure-bonding The buffer compositions for footwear in Examples and Comparative Examples were each formed into a strip shape (width 20 mm × length 60 mm × thickness 3 mm), and strip surface Was treated with a urethane coating agent to obtain a test piece 51. The test piece 51 was bonded to the urethane piece 52 (Kuraray Co., Ltd. Kuramylon U2195, width 20 mm × length 60 mm × thickness 3 mm) and the adhesive 53, which were also produced in the same strip shape, to obtain a sample piece 50. More specifically, the surfaces of the test piece 51 and the urethane piece 52 were wiped with Kimwipe (registered trademark) soaked in methyl ethyl ketone (MEK), and then dried at 60 ° C. for 3 minutes. A primer (G-6626, manufactured by Notape Industry Co., Ltd.) was applied to the surface of the test piece 51 treated with the urethane coating agent and one surface of the urethane piece 52, and dried at 60 ° C. for 5 minutes. On top of that, an adhesive (No. 4950, manufactured by No Tape Kogyo Co., Ltd.) was applied and dried at 60 ° C. for 5 minutes, and then the test piece 51 and the urethane piece 52 were quickly bonded together. The sample piece 50 was obtained by placing the test piece 51 side up and pressing it with a hand roller by applying a force of 2 to 3 kgf / cm ² . After the sample piece 50 was cured for 12 hours, the peel adhesion strength was measured using the tensile tester described above.

(3-2) Sample piece: Primer-treated layer present / insert molding Urethane piece 52 (Kuraray Co., Ltd. Kuramyron U2195, width 20 mm × length 60 mm × thickness 3 mm) produced in a strip shape was bonded to methyl ethyl ketone (MEK). ) Wiped with Kimwipe (registered trademark) soaked in 3), dried at 60 ° C. for 3 minutes, coated with a primer (G-6626, manufactured by Notape Industrial Co., Ltd.) and dried at 60 ° C. for 5 minutes. To obtain a primer-treated urethane piece. The primer-treated urethane piece was placed so that the primer-treated surface was exposed in the cavity of the injection mold. The footwear buffer compositions in the examples and comparative examples were insert injection molded under conditions of 150 to 190 ° C. together with the primer-treated urethane piece 52, and the width 20 mm × length 60 mm × on the primer-treated layer of the urethane piece 52. A sample piece 50 in which a strip-like test piece 51 having a thickness of 3 mm was integrally formed was obtained. After the sample piece 50 was cured for 12 hours, the peel adhesion strength was measured using the tensile tester described above.

(3-3) Sample piece: No primer treatment layer / insert molding Primer treatment on a strip of urethane piece 52 (Kuraray Co., Ltd. Kuramiron U2195, width 20 mm x length 60 mm x thickness 3 mm) In the same manner as the sample piece manufacturing method (3-2) above, a strip-like test piece 51 having a width of 20 mm, a length of 60 mm and a thickness of 3 mm is integrally formed on the surface of the urethane piece 52. The obtained sample piece 50 was obtained. After the sample piece 50 was cured for 12 hours, the peel adhesion strength was measured using the tensile tester described above.

(4) Adhesion state Regarding the peeling state of each sample piece after the above-described peel adhesion strength tests (3-1) to (3-3), the adhesion state of each test piece was visually or microscopically observed. evaluated. The case where material destruction (adhered body destruction) occurred was designated as “AF”, and the case where interface peeling occurred at the interface between the molded article of the footwear buffer composition and the adherend was designated as “IP”. Furthermore, for the evaluation of adhesion, the peel adhesion strength of the sample piece with the primer treatment layer (3-1) and pressure-bonded and the sample piece with the primer treatment layer (3-2) and insert molding of (3-2) were evaluated. A sample piece having a material fracture of 2.5 kgf / 20 mm or more and having a material fracture was evaluated as “Good”, and the peel adhesion strength was less than 2.5 kgf / 20 mm or the interface piece was poorly adhered. It was evaluated. In addition, for the sample piece of (3-3) without primer treatment layer / insert molding, the sample piece having a peel adhesion strength of 1.0 kgf / 20 mm or more was evaluated as having excellent adhesion, and the peel adhesion strength was evaluated. Sample pieces having a thickness of less than 1.0 kgf / 20 mm were evaluated as “x” having poor adhesion.

(5) Surface appearance About the test piece used for the hardness test, from a viewpoint of commercial value, the presence or absence of a crack, a bubble, cloudiness, and a nonuniformity was confirmed visually, and the surface appearance was evaluated. Excellent “◯” when there are no scratches, bubbles, cloudiness, and unevenness, and “△” when there is at least one of scratches, bubbles, cloudiness, and unevenness but the commercial value is acceptable “△”, no commercial value The case was judged as “No”.

Table 1 shows the specifications of each component used in the following examples and comparative examples. Here, the molecular weight Mw in Table 1 is the component NO. It is a weight average molecular weight measured by gel permeation chromatography (GPC) method excluding A301. Specifically, the molecular weight Mw is measured using SHODEX (registered trademark) GPC-104 (manufactured by Showa Denko KK) [separation column LF-404 (three connected), guard column LF-G, RI detector RI- 74S (both Showa Denko Co., Ltd.)], and the eluent was tetrahydrofuran, and the sample concentration was 10 mg / 4 mL, the eluent flow rate was 0.3 mL / min, and the column temperature was 40 ° C. In addition, component NO. The molecular weight of A301 is indicated by the number average molecular weight Mn.

[Supplement under rule 26 18.08.2016]

[Example 1]
The cushioning composition for footwear of this example was produced by the following procedure, and the effect was evaluated. Of the styrenic thermoplastic elastomers (component A) shown in Table 1, the block copolymer (a1) represented by S-EB / SS is a block copolymer having a styrene content of 42% and a weight average molecular weight of 150,000. 600 g (20 wt%) of the copolymer (A101), 600 g (20 wt%) of a block copolymer (A201) having a styrene content of 30% and a weight average molecular weight of 67,000 as amine-modified S-EB-S (a2), Each was weighed individually. Next, 1800 g (60 wt%) of paraffin oil (B103) having a weight average molecular weight of 1200 of the softener (component B) shown in Table 1 was weighed. Of this paraffin oil, 1200 g (40 wt%) was added to the a1 component and 600 g (20 wt%) was added to the a2 component. Each block copolymer and paraffin oil were mixed at room temperature and then heated at 100 ° C. for 12 hours to disperse the paraffin oil in each of the components a1 and a2 (preliminary dispersion step). The block copolymer of a1 and a2 that has absorbed paraffin oil is dry-blended by hand stirring, and then in a batch type twin-screw kneader (TD3-10MDX type manufactured by Toshin Co., Ltd.) according to the molecular weights of the a1 and a2 components In the range of 120 to 200 ° C., the mixture was kneaded for 15 minutes at a rotation speed of 40 rpm (kneading step) to obtain 3000 g of a footwear buffer composition. This composition was injection-molded under a condition of 130 to 190 ° C. into a predetermined test piece shape used in each of the above-described footwear buffer composition evaluation methods, and physical properties and the like were evaluated using the obtained test piece. .

[Examples 2 to 20]
Except that the styrene-based thermoplastic elastomer (component A) and the softener (component B), which are constituents of the buffer composition for footwear, and the blending ratio thereof were changed as shown in Tables 2 to 4 below, Examples The footwear buffer composition of each example was obtained in the same manner as in Example 1. In the same manner as in Example 1, a test piece for evaluating physical properties was molded using the obtained footwear buffer composition, and physical properties and the like were evaluated.

Table 2 shows the results of Examples 1 to 7, Table 3 shows the results of Examples 8 to 13, and Table 4 shows the results of Examples 14 to 20. Here, the “MFR difference after pre-dispersion” in the table is the difference in the melt viscosity (MFR: melt mass flow rate) values of the components a1 and a2 in the state where the softener (component B) is dispersed. is there. Specifically, for the a1 and a2 components after the pre-dispersion treatment, the melt mass flow rate at 190 ° C. in accordance with JIS K7210-1B method was measured, and the difference between the melt viscosity of the a1 component and the melt viscosity of the a2 component was calculated. Value (the same applies to Tables 5 to 7 below).

[Supplement under rule 26 18.08.2016]

[Supplement under rule 26 18.08.2016]

[Supplement under rule 26 18.08.2016]

[Comparative Examples 1 to 20]
Composition of each comparative example in the same manner as in Example 1, except that the styrene-based thermoplastic elastomer (component A), the softening agent (component B) and the blending ratio thereof were changed as shown in Tables 5 to 7 below. Got. In the same manner as in Example 1, a test piece for evaluating physical properties was molded using the obtained composition, and physical properties and the like were evaluated. The results of Comparative Examples 1 to 9 are shown in Table 5, the results of Comparative Examples 10 to 17 are shown in Table 6, and the results of Comparative Examples 18 to 20 are shown in Table 7, respectively.

[Supplement under rule 26 18.08.2016]

[Supplement under rule 26 18.08.2016]

[Supplement under rule 26 18.08.2016]

From the comparison results of Examples 1 to 20 shown in Tables 2 to 4 and Comparative Examples 1 to 20 shown in Tables 5 to 7, the composition of the present invention was used to make the composition flexible and mechanical strength. It has been found that a footwear cushioning composition suitable for forming a footwear cushioning member having an adhesive property and excellent adhesion can be obtained. Moreover, it was also found that the cushioning members formed from these footwear cushioning compositions were superior to the comparative examples in adhesion to other members in the same adhesion conditions, regardless of the presence or absence of primer treatment. The results are described in detail below.

The results of Examples 1, 4 and 5 using S-EB / SS as the block copolymer (a1) and the block copolymer (a1) in Examples 1, 4 and 5 were converted to S-EB-S From the comparison of the results of Comparative Examples 1 to 9 replaced with (a3), in order to obtain a buffer member exhibiting excellent physical properties of adhesiveness, flexibility, and mechanical strength, the intermediate block has an EB / S structure. The block copolymer (a1) was found to be effective. In addition, when the styrene-based thermoplastic elastomer (A) does not contain the component a1 and is composed only of the block copolymer (a2) as in Comparative Example 11, the tear strength decreases, and therefore In order to obtain the effect, it was found that the component a1 is an essential component. Further, from comparison between Examples 5, 6, 16, 17, 19 and 20 and Comparative Examples 10, 11, 14 and 15, it was found that the block copolymer (a1) and the modified styrene-ethylene-butylene-styrene block copolymer. If the blending ratio of (a2) is by weight and deviates from the lower limit of the range of a2 / (a1 + a2) = 0.25 to 0.95, the peel adhesive strength decreases and the adhesiveness is inferior. It was found that the mechanical strength was inferior. Further, from the results of Examples 1, 4, 5 and 6 and Examples 14 to 17, the modified styrene-ethylene-butylene-styrene block copolymer (a2) is both an amine-modified product and a maleic anhydride-modified product. It turned out to be effective. Further, from the results of Examples 1, 5, 6 and Examples 18 to 20, it was found that the block copolymer (a1) is preferably an acid-modified product, that is, a maleic anhydride-modified product. Further, from the comparison between Examples 8 to 11 and Comparative Examples 12 to 13, the weight ratio of A / (A + B) was 0.00 for the blending ratio of the styrenic thermoplastic elastomer (A) and the softening agent (B). If it is less than 5, the hardness becomes high and the flexibility is poor, and if it exceeds 0.7, the softening agent (B) is excessively added, so that the adhesiveness and the mechanical strength are lowered, so A / (A + B) = 0.5 to A range of 0.7 was found to be effective. From the results of Example 1 in Table 1 and Examples 12 and 13 in Table 2, when paraffin oil was applied as the softener (B), the molecular weight of the paraffin oil was at least in the range of 400 to 1200. It was confirmed that a shock-absorbing member having excellent physical properties, flexibility and mechanical strength can be obtained.

[Examples 21 to 23]
In Example 1, except that the distribution ratio of the softener (B) individually absorbed for each of the components a1 and a2 constituting the styrene-based thermoplastic elastomer (A) in the preliminary dispersion step is as shown in Table 8. In the same manner as in Example 1, the footwear buffer composition of each Example was obtained. The value of Bi / ai (where i = 1, 2) in Table 8 indicates the blending ratio of the softening agent (B) with respect to each component of a1 and a2. The MFR in the table is the melt viscosity of the a1 and a2 components (melt mass flow rate, JIS K7210-1B method), and the melt viscosities of the a1 and a2 components were measured. The measurement conditions of the melt viscosity before dispersing the softener (B) (before treatment) are 230 ° C. and the load is 2.16 kg. The measurement condition of the melt viscosity after dispersion (after treatment) is 190 ° C. The load was 2.16 kg. Moreover, the difference of the melt viscosity value of a1 component and a2 component was computed about the melt viscosity (MFR) after a dispersion process. Using the obtained footwear buffer composition, the dispersibility (appearance) of the composition after the kneading step was evaluated. Evaluation of dispersibility is visual appearance evaluation, good ◯ when there is no inhomogeneous phase with insufficient dispersion, and unsuitable `` x '' when it contains a heterogeneous phase or becomes cloudy and has extremely poor transparency. did. Also, this footwear buffer composition is injection molded under the conditions of 130 to 190 ° C. into a predetermined test piece shape used in each of the above-described footwear buffer composition evaluation methods, and the obtained test piece is used for physical properties and the like. Was evaluated.

[Comparative Example 21]
Except that the components a1 and a2 constituting the styrene-based thermoplastic elastomer (A) were mixed well, and then the softening agent (B) was added to the mixture and dispersed, in the same manner as in Example 1, The composition of this comparative example was obtained in the same manner as in Example 1. That is, in this comparative example, the softening agent (B) is not subjected to a step (preliminary dispersion step) in which the softening agent (B) is previously dispersed in the components a1 and a2 constituting the styrene thermoplastic elastomer (A). In the same manner as in Examples 21 to 23, the obtained composition was evaluated for the dispersibility (appearance) of the composition after the kneading step. In addition, this composition was injection molded under the conditions of 130 to 190 ° C. into a predetermined test piece shape used in each of the above-described evaluation methods for footwear buffer compositions, and physical properties and the like were evaluated using the obtained test piece. went.

Table 8 shows the results of Examples 21 to 23 and Comparative Example 21 together with the results of Example 1.

As shown in Table 8, the footwear buffer compositions of Example 1 and Examples 21 to 23 have good dispersibility of each component after heating and kneading, and have an appearance, tear strength, hardness and adhesiveness. All were good results. On the other hand, the composition of Comparative Example 21 has a macro-inhomogeneous phase in the composition after kneading, and the heterogeneous phase has a large variation in all physical property values of tear strength, peel adhesion strength, and appearance. Was found to be unstable. Therefore, in the preliminary dispersion step, the softening agent (B) is dispersed in advance in each component constituting the styrene-based thermoplastic elastomer (A), so that it is easily dispersed uniformly in the kneading step, and the adhesiveness is increased. -It was found that a buffer composition for footwear having excellent physical properties of flexibility and mechanical strength and stable quality can be obtained. Further, from the comparison between Examples 1, 21 and 22 and Example 23, it is the same when the softening agent (B) is absorbed in each of the a1 and a2 components constituting the styrenic thermoplastic elastomer (A) in the preliminary dispersion step. The higher the melt viscosity at temperature, the higher the distribution ratio of the softening agent (B) per unit weight, so that a cushioning member for footwear that is further excellent in tear strength and appearance (transparency) can be obtained. I understood. This is considered to be because the difference in inherent melt viscosity between the block copolymers a1 and a2 is reduced by the blending as described above, and each component is easily dispersed uniformly in the heating and kneading step. In Tables 2 to 7, the values of the melt viscosity before the preliminary dispersion treatment of the a1 component and the a2 component are not described, but in Examples 2 to 20, the magnitude relationship between the melt viscosities of the a1 component and the a2 component is a2 ≦ a1. Furthermore, from comparison between Examples 1 and 21 and Example 22, the difference in MFR (g / 10 min) between component a1 and component a2 after absorbing softener (B) is 150 or less. It was found that the appearance was further improved in terms of transparency by adjusting the amount of the softening agent (B) absorbed by each component. This suggests that the uniform dispersibility in the kneading step is further improved, and the difference in MFR (g / 10 min) between the a1 component and the a2 component after the preliminary dispersion step is set to 150 or less so that the transparency is improved. It was found that a high-quality cushioning member for footwear with little variation in physical properties such as the above can be obtained.

The present invention is not limited to the above-described embodiments or examples, and various design changes within the scope not departing from the gist of the invention described in the claims are also included in the technical scope. Is.

DESCRIPTION OF SYMBOLS 1 Molded body of footwear cushioning composition 10, 11 Footwear cushioning member 10a An example of a part which needs to improve adhesiveness 2 Primer treatment layer 3 Protective layer 40 Sports shoes 41 Sole part heel part 42 Side edge of sole part Part 50 Sample piece 51 Test piece (buffer member of Example or Comparative Example)
52 Urethane piece 53 Adhesive layer 54 Fixed side tension jig 55 Movable side tension jig

Claims (12)

1. A composition containing a styrenic thermoplastic elastomer (A) and a softening agent (B),
   The styrenic thermoplastic elastomer (A) is
   A block copolymer (a1) obtained by hydrogenating a block copolymer XYX comprising both terminal blocks X comprising a styrene polymer block and an intermediate block Y comprising a copolymer block of styrene and butadiene. )When,
   A modified styrene-ethylene-butylene-styrene block copolymer (a2),
   The a2 block copolymer is an amine-modified block copolymer or a maleic anhydride-modified block copolymer,
   The blending ratio of the a1 and a2 block copolymers is a2 / (a1 + a2) = 0.25 to 0.95 in weight ratio,
   A footwear buffer composition, wherein the blending ratio of the styrenic thermoplastic elastomer (A) and the softening agent (B) is B / (A + B) = 0.5 to 0.7 in terms of weight ratio.
2. The footwear buffer composition according to claim 1, wherein the block copolymer of a1 is acid-modified.
3. The footwear buffer composition according to claim 1 or 2, wherein the softening agent (component B) is a paraffinic oil having a molecular weight of 400 to 1200.
4. The footwear buffer composition according to any one of claims 1 to 3, further comprising hollow body fine particles.
5. The footwear buffer composition according to any one of claims 1 to 4, wherein the hardness of the molded body is Asker C30-50 (SRIS 0101 standard 23 ± 2 ° C).
6. A block copolymer (a1) obtained by hydrogenating a block copolymer XYX comprising both terminal blocks X comprising a styrene polymer block and an intermediate block Y comprising a copolymer block of styrene and butadiene. ) And a modified styrene-ethylene-butylene-styrene block copolymer (a2), a styrenic thermoplastic elastomer (A), and a softener (B),
   The a2 block copolymer is an amine-modified block copolymer or a maleic anhydride-modified block copolymer,
   The blending ratio of the a1 and a2 block copolymers is a2 / (a1 + a2) = 0.25 to 0.95 in weight ratio,
   Footwear formed by molding a footwear buffer composition in which the blending ratio of the styrenic thermoplastic elastomer (A) and the softening agent (B) is B / (A + B) = 0.5 to 0.7 by weight. Cushioning member.
7. The footwear cushioning member according to claim 6, wherein the block copolymer a1 is acid-modified.
8. The footwear cushioning member according to claim 6 or 7, wherein the footwear cushioning composition further contains hollow body fine particles and has a plurality of closed cells inside.
9. Footwear, wherein the foot cushioning member according to any one of claims 6 to 8 is disposed on an insole or a midsole.
10. A pre-dispersing step in which the softening agent (B) is dispersed in advance in at least one component of the block copolymers a1 and a2.
    The footwear buffer composition according to any one of claims 1 to 4, further comprising a kneading step in which the block copolymers a1 and a2 that have undergone the preliminary dispersion step are mixed and heat-kneaded. Method.
11. The softening agent (B) in the preliminary dispersion step is dispersed in each component of the block copolymers a1 and a2, and the higher the melt viscosity at the same temperature, the softening agent per unit weight. The method for producing a buffer composition for footwear according to claim 10, wherein the blending amount of (B) is increased.
12. The dispersion of the softening agent (B) in the preliminary dispersion step is performed on each component of the block copolymers a1 and a2, respectively.
    The dispersion of the softener (B) with respect to each component of the block copolymers a1 and a2 is the melt viscosity (melt mass flow rate, MFR: JIS K7210-) of each component in the state where the softener (B) is dispersed. 1B method (value represented by 190 ° C.), the blending amount of the softening agent (B) is adjusted so that the difference in the melt viscosity of each component is 150 (g / 10 min) or less. The manufacturing method of the buffer composition for footwear of Claim 10.

Images