JP6938727B2 - Thermoplastic polyester elastomer foam - Google Patents

Description

The present invention relates to a thermoplastic polyester elastomer foam.

Conventionally, as a sole member used for walking, jogging, running, etc., there is a member in which a low-resilience foam and a high-resilience foam are laminated (Patent Document 1).
Further, it is also known that a shoe sole is formed by combining EVA, polyurethane foam, rubber and the like.

However, for sports where jumping is important, such as volleyball, basketball, soccer, and athletics jumping, or sports shoes used for jogging, running, etc., it is lighter, has higher impact resilience, and is permanently compressed. There is a demand for a member for a shoe sole having a small (sett). When the foaming ratio of the foam was increased in order to reduce the weight, the impact resilience decreased, and both the weight reduction and the impact resilience could not be improved. It is considered that if the foaming ratio is forcibly increased, the cell structure becomes non-uniform and coarse, or the cells aggregate to generate a large amount of voids, and as a result, the rebound resilience decreases.

Japanese Patent No. 5257714

The present invention has been made in view of the above points, and is lightweight and has high impact resilience, which is suitable for sports in which jumping is important, or sole members of sports shoes used for jogging, running, and the like. An object of the present invention is to provide a thermoplastic polyester elastomer foam having a small compression set.

The invention of claim 1 is a thermoplastic polyester elastomer foam, wherein the thermoplastic polyester elastomer foam has a crosslinked structure by a siloxane bond and has a closed cell structure in which a skin layer is formed on one side or both sides, and is compressed. It is characterized in that the permanent distortion is 50% or less.

The invention of claim 2 is characterized in that, in claim 1, a melt viscosity modifier is added to the thermoplastic polyester elastomer foam.

According to a third aspect of the present invention, in the first or second aspect, the thermoplastic polyester elastomer foam is provided as a sole member at a portion corresponding to a stepping portion and a heel portion of the sole of the foot. It is characterized by.

The invention of claim 4 is characterized in that, in any one of claims 1 to 3, the foaming ratio of the thermoplastic polyester elastomer foam is 2.5 to 10 times.

According to the present invention, it is possible to obtain a thermoplastic polyester elastomer foam which is lightweight, has high impact resilience, has low compression set, and is suitable as a member for soles.

It is a perspective view of the shoe which used the thermoplastic polyester elastomer foam of this invention as a member for soles. It is a top view and a cross-sectional view of the midsole of the shoe. It is a table which shows the compounding, manufacturing conditions, physical characteristics, etc. of Examples 1 to 13. It is a table which shows the compounding, manufacturing conditions, physical characteristics, etc. of Examples 14 to 20 and Comparative Examples 1 to 3.

Hereinafter, embodiments of the present invention will be described.
The thermoplastic polyester elastomer foam of the present invention has a crosslinked structure due to a siloxane bond, has a density of 0.1 to 0.4 g / cm ³ , a rebound resilience of 60% or more, and a compression set of 50% or less. It is suitable for sports shoes because it is lightweight, has excellent impact resilience, and has low compressive settling.

The density is a value measured based on JIS K7222: 2005. The impact resilience is a value measured based on JIS K6400-3: 2011. The compression set is a value measured based on the JIS K6262: 2013 A method.

The specific method for measuring the compression set is as follows. First, the thickness h0 of the measurement sample left for 3 hours in an environment of a temperature of 23 ± 2 ° C. and a humidity of 50 ± 10% before the test is measured. Next, the measurement sample was compressed by 50% with respect to the thickness h0 before the test, and the compression device incorporating the measurement sample was put into a constant temperature and humidity chamber kept at a temperature of 50 ° C. and a humidity of 50% in advance. 6 Let stand for a while. The thickness h2 of the spacer used at this time (thickness of 50% with respect to the thickness h0 of the measurement sample before the test) is measured. After 6 hours in the compressed state, remove the compression device from the constant temperature and humidity chamber, release the compressed state, and test the measurement sample after 30 ± 3 minutes in an environment with a temperature of 23 ± 2 ° C and a humidity of 50 ± 10%. The subsequent thickness h1 is measured. The compression set (%) is calculated by the following formula.
Compressive permanent strain (%) = [(h0-h1) / (h0-h2)] × 100

The method for producing the thermoplastic polyester elastomer foam of the present invention will be described. The method for producing a thermoplastic polyester elastomer foam of the present invention includes a grafting step, a foaming step, and a static crosslinking step.

In the grafting step, the thermoplastic polyester elastomer and the modified silane coupling agent are melt-kneaded to graft the modified portion of the modified silane coupling agent onto the thermoplastic polyester elastomer, and the thermoplastic polyester having an alkoxysilyl group is obtained. Make elastomer pellets. At that time, a melt viscosity modifier may be added.

The thermoplastic polyester elastomer (TPEE) has a hard segment and a soft segment, and is not particularly limited in the present invention. Examples of the hard segment include crystalline polyesters such as polybutylene terephthalate, polybutylene naphthalate, and polyethylene terephthalate. Examples of the soft segment include polyoxyalkylene glycols such as polytetramethylene glycol, polyesters such as polycaprolactone and polybutylene adipate, and the like.

Examples of the modified portion (functional group) of the modified silane coupling agent include epoxy modification, amine modification, vinyl modification and the like, but an epoxy-modified silane coupling agent having high reactivity with a thermoplastic polyester elastomer is more preferable. The blending amount of the epoxy-modified silane coupling agent is preferably 0.1 to 5 parts by weight, more preferably 0.1 to 2 parts by weight, and 0.1 to 1 part by weight with respect to 100 parts by weight of the thermoplastic polyester elastomer. Especially preferable.
Further, a grafting promotion catalyst may be added to promote the grafting reaction. Examples of the grafting promotion catalyst include tertiary amines and onium salts. Examples of the tertiary amine include N, N-dimethylaminopyridine and N-methylimidazole, and examples of the onium salt include quaternary ammonium salts such as tetrabutylammonium bromide and tetrapropylammonium bromide. The blending amount of the grafting promotion catalyst is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the thermoplastic polyester elastomer.

Examples of the melt viscosity modifier include a modified styrene-acrylic copolymer, acrylic-modified polytetrafluoroethylene, and a high-molecular-weight polyester elastomer. The melt viscosity modifier may be used alone or in combination of two or more.
It is more preferable to use a modified styrene-acrylic copolymer or acrylic-modified polytetrafluoroethylene as the melt viscosity modifier.
In the case of the modified styrene-acrylic copolymer, the ester group of the thermoplastic polyester elastomer reacts with the modified portion (functional group such as isocyanate group or epoxy group) to increase the molecular weight, thereby increasing the melt viscosity. (The modified styrene-acrylic copolymer functions as a chain extender or crosslinker).
In the case of the acrylic-modified polytetrafluoroethylene, the melt viscosity can be increased by loosening (fibrillating) the bundles of the polytetrafluoroethylene fibers by the shearing force and forming a fibrous network structure. By acrylic-modifying polytetrafluoroethylene, dispersibility in the thermoplastic polyester elastomer can be improved and fibrillation can be efficiently generated (acrylic-modified polytetrafluoroethylene functions as a thixotropy agent). ..

The modified portion (functional group) of the modified styrene-acrylic copolymer is preferably an epoxy group. The epoxy-modified styrene-acrylic copolymer preferably has an epoxy equivalent of 200 to 2800 and a weight average molecular weight (Mw) of 2000 to 25000, an epoxy equivalent of 250 to 1800, and a weight. More preferably, the average molecular weight (Mw) is 4000 to 15000. If the epoxy equivalent of the epoxy-modified styrene-acrylic copolymer is less than 200, a sufficient viscosity adjusting effect cannot be obtained, and if the epoxy equivalent exceeds 2800, the viscosity increases excessively, which adversely affects the moldability. Sometimes. Further, when the weight average molecular weight of the epoxy-modified styrene-acrylic copolymer is less than 2000, the surface of the foam may be contaminated by volatilizing during molding or bleeding out to the surface of the molded product. .. On the other hand, when the weight average molecular weight exceeds 25,000, the reactivity of the thermoplastic polyester elastomer with the ester group may decrease, the viscosity may not be adjusted appropriately, or the compatibility with the thermoplastic polyester elastomer may deteriorate. be. The epoxy equivalent was measured in accordance with JIS K7236: 2001.

When the melt viscosity modifier is blended, the blending amount is preferably 0.05 to 1.5 parts by weight, more preferably 0.1 to 1 part by weight, based on 100 parts by weight of the thermoplastic polyester elastomer. If it is less than 0.05 parts by weight, the effect of adjusting the viscosity is small, while if it exceeds 1.5 parts by weight, the viscosity of the thermoplastic polyester elastomer becomes too high and the moldability tends to be deteriorated.

As a method of blending the melt viscosity modifier into the thermoplastic polyester elastomer, a method of blending and melt-kneading the thermoplastic polyester elastomer, the modified silane coupling agent, and the melt viscosity modifier to prepare pellets (final pellets), heat. A method in which only a plastic polyester elastomer and a modified silane coupling agent are blended and melt-kneaded to prepare a primary pellet, and a melt viscosity modifier is blended and melt-kneaded into the prepared primary pellet to prepare a final pellet. Examples thereof include a method in which only a melt viscosity modifier is blended and melt-kneaded to prepare a primary pellet, and a modified silane coupling agent is blended with the prepared primary pellet and melt-kneaded to prepare a final pellet. As long as the thermoplastic polyester elastomer, the modified silane coupling agent, and the melt viscosity modifier can be melt-kneaded by a twin-screw extruder, the final pellet may be prepared by any method, but in order to simplify the final pellet preparation process. It is preferable that the thermoplastic polyester elastomer, the modified silane coupling agent, and the melt viscosity modifier are mixed and melt-kneaded at the same time to prepare final pellets.

The temperature in the grafting step may be equal to or higher than the temperature at which the thermoplastic polyester elastomer melts, but if the temperature is too high, the thermoplastic polyester elastomer may undergo thermal decomposition. Therefore, 200 to 300 ° C. is preferable. ~ 250 ° C. is more preferable.

In the foaming step, the thermoplastic polyester elastomer having an alkoxysilyl group obtained by the grafting step is foamed to produce a thermoplastic polyester elastomer foam having an alkoxysilyl group.
In the foaming step, it is preferable to use pellets (final pellets) containing a melt viscosity modifier. By using pellets containing a melt viscosity modifier, a foam having more uniform cells can be obtained, and the impact resilience can be further enhanced.

Examples of the foaming method include known foaming methods such as a chemical foaming method, a physical foaming method, and a supercritical foaming method. The chemical foaming method is a foaming method using a chemical foaming agent such as azodicarbonamide. The physical foaming method is a foaming method in which a physical foaming agent such as a liquefied gas is dissolved in a resin under high pressure to generate bubbles by reducing the pressure or heating. The supercritical foaming method is a foaming method in which a supercritical fluid is dissolved in a resin under high pressure to generate bubbles by reducing the pressure. In particular, the supercritical foaming method is preferable.

In the static cross-linking step, the thermoplastic polyester elastomer foam having the alkoxysilyl group obtained in the foaming step is statically reacted with a water component to make the alkoxysilyl group silanol-based, and then the silanol group. The thermoplastic polyester elastomer foam of the present invention is produced by forming a siloxane bond between them by a condensation reaction. The static reaction in the present invention means that the thermoplastic polyester elastomer foam having an alkoxysilyl group and a water component are brought into contact with each other outside the kneading apparatus.

In the static cross-linking step, it is preferable to add a silanolification promoting catalyst for promoting silanolization. If the silanolization promoting catalyst is not added, the reaction time becomes long and it is inefficient. The blending amount of the silanolization promoting catalyst is preferably 0.01 to 2 parts by weight, more preferably 0.1 to 1.5 parts by weight, based on 100 parts by weight of the thermoplastic polyester elastomer.

The silanolification promoting catalyst is preferably used in a catalyst masterbatch. As the resin for masterbatch, a polyester-based polymer is preferable, a thermoplastic polyester elastomer is more preferable, and it is particularly preferable that the resin is equal to the main thermoplastic polyester elastomer. In the catalyst masterbatch, the amount of the catalyst is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the resin for the masterbatch. The optimum amount of the catalyst masterbatch is different depending on the type of resin and the mixing ratio of the resin and the catalyst, but as a preferable example, it is more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the main thermoplastic polyester elastomer. The blending amount is 3 to 15 parts by weight.

The static reaction between the thermoplastic polyester elastomer foam having an alkoxysilyl group and the water component in the static cross-linking step is carried out by bringing the thermoplastic polyester elastomer foam having an alkoxysilyl group into contact with the water component. The contact method between the thermoplastic polyester elastomer foam having an alkoxysilyl group and the water component may be any method as long as the water component comes into contact with the foam, and is not particularly limited. It can be used and the like. For example, when immersed in water, if the thermoplastic polyester elastomer foam having an alkoxysilyl group is immersed in warm water at about 50 ° C. to 95 ° C. for about 10 minutes to 6 hours, the crosslinking reaction can proceed quickly and the crosslinking time can be shortened. It is possible and preferable. Further, when steam is applied, if an autoclave (heating pressure cooker) is used, the treatment can be performed under conditions of higher temperature and pressure than hot water, so that the cross-linking time can be further shortened.

The thermoplastic polyester elastomer foam can be produced by a continuous step of continuously performing the grafting step, the foaming step, and the static cross-linking step, or by a discontinuous step performed discontinuously.

In the case of a continuous process, a thermoplastic polyester elastomer, a modified silane coupling agent, a silanol conversion accelerating catalyst, etc. are mixed from the beginning and supplied to a twin-screw extruder, grafted by the twin-screw extruder, and heat having an alkoxysilyl group. Make pellets of thermoplastic polyester elastomer. Then, the pellet is foamed by an injection molding machine and then statically contacted with a water component to carry out cross-linking to obtain a thermoplastic polyester elastomer foam having a cross-linked structure by a siloxane bond.

The method of foaming the pellets with an injection molding machine will be described when the pellets are foamed by a known supercritical gas injection molding method.
A melted thermoplastic polyester elastomer, a modified silane coupling agent, a silanolization accelerating catalyst, a supercritical physical foaming agent, and an appropriate melt viscosity modifier are melt-mixed and injected into the mold cavity. Then, the mold is cored back to foam to form a foam. The foaming ratio can be adjusted by adjusting the total weight of the thermoplastic polyester elastomer or the like filled in the cavity before the core back and the amount of the mold to be core backed. By increasing the capacity of the final cavity after the core back, the foaming ratio can be increased. The foaming ratio of the foam is preferably 2.5 to 10 times, more preferably 3 to 9 times.

The total weight of the resin or the like filled in the cavity before the core back may be either a full shot equal to the cavity capacity or a short shot smaller than the cavity capacity. In the case of a short shot, an amount 5 to 20% less than the total weight of the resin or the like that can be filled in the cavity volume is injected into the cavity.

After foaming by the core bag, the foam is cooled in the mold and the foam is taken out from the mold. A thermoplastic polyester elastomer foam having an alkoxysilyl group taken out from a mold is immersed in warm water at about 90 ° C. for about 60 minutes and statically crosslinked to have a crosslinked structure by siloxane bond, and a skin layer is formed on the surface. The thermoplastic polyester elastomer foam of the present invention having a closed cell structure having a closed cell structure can be obtained.

By cutting the thermoplastic polyester elastomer foam having a closed cell structure having a crosslinked structure by siloxane bond and having a skin layer on the surface into a predetermined size while keeping the thickness as it is. , A thermoplastic polyester elastomer foam having a closed cell structure having a crosslinked structure by a siloxane bond and having a skin layer on both sides can be obtained. On the other hand, a thermoplastic polyester elastomer foam having a closed cell structure having a crosslinked structure by a siloxane bond and a skin layer on the surface is divided into two thicknesses and cut into a predetermined size to obtain siloxane. A thermoplastic polyester elastomer foam having a closed-cell structure having a crosslinked structure by bonding and having a skin layer on one side can be obtained.

Examples of the physical foaming agent used in the supercritical gas injection molding method include nitrogen and carbon dioxide. When a chemical foaming agent such as azodicarbonamide (ADCA) is used instead of the physical foaming agent, the cell structure of the obtained foam tends to be coarse, and it is preferable to use the physical foaming agent.

The merit in the case of the continuous step is that it is possible to produce a thermoplastic polyester elastomer foam having a crosslinked structure by a siloxane bond and a skin layer on the surface in the continuous step, which is efficient. On the other hand, the disadvantage is that the alkoxysilyl group of the thermoplastic polyester elastomer having an alkoxysilyl group comes into contact with the water component in the air because the thermoplastic polyester elastomer, the modified silane coupling agent and the silanolization promoting catalyst are blended from the beginning. Then, a cross-linking reaction (alkoxysilyl group forms siloxane bond via silanol group) occurs, and the pot life of the raw material is short.

In the case of a discontinuous process, first, the thermoplastic polyester elastomer and the modified silane coupling agent are mixed with a blender, melt-kneaded with a kneading device such as a uniaxial kneading extruder, a twin-screw kneading extruder, and a Banbury mixer to form a graft, and pelletized. To make. After that, using pellets and a catalyst master batch, injection is performed into a mold by an injection molding machine to obtain a thermoplastic polyester elastomer foam having an alkoxysilyl group, and then the foam is brought into contact with a water component to form a siloxane bond. A thermoplastic polyester elastomer foam having a closed cell structure having a crosslinked structure and a skin layer on the surface is obtained.
In the present specification, the pellet refers to a thermoplastic polyester elastomer having an alkoxysilyl group, and the catalyst masterbatch refers to a masterbatch of a silanolification promoting catalyst.

The merit in the case of the discontinuous process is that the pot life of the raw material is longer than in the case of the continuous process because the catalyst masterbatch is blended immediately before the foaming process. On the other hand, the efficiency is lower than that of the continuous process, and care must be taken in storage so that the pellets do not come into contact with water components in the air and cause reactions such as hydrolysis reaction and condensation reaction. be.

Next, an example of using the thermoplastic polyester elastomer foam of the present invention will be shown. The shoe 10 shown in FIG. 1 is an example in which the thermoplastic polyester elastomer foam of the present invention is used as the sole members 41 and 43. Reference numeral 11 is an upper, 21 is a midsole, and 31 is an outsole. The midsole 21 and the outsole 31 form a sole.

As shown in FIG. 2, on the upper surface of the midsole 21, the sole members 41 and 43 of the example of the present invention are embedded in the portions corresponding to the stepping portion and the heel portion on the sole of the foot. .. The sole member 41 provided in the portion corresponding to the stepping portion alleviates the impact applied to the vicinity of the base of the toes during jumping, running, etc., and repels the force when kicking the ground. It acts to increase with force. On the other hand, the sole member 43 provided at the portion corresponding to the heel portion acts to alleviate the impact applied to the vicinity of the heel at the time of landing or the like during jumping or running.

The sole member 41 provided at the portion corresponding to the stepping portion is formed of a horizontally long rectangle so as to act on the range from the base of the big toe to the base of the little finger. On the other hand, the sole member 43 embedded in the portion corresponding to the heel portion has a substantially circular shape so as to act on the center of the heel portion. The thickness of the sole members 41, 43 embedded in the upper surface of the midsole 21 depends on the thickness of the midsole 21, but a preferable range is about 2 to 20 mm. The sole members 41 and 43 may be embedded so as to penetrate above and below the midsole 21, or may be arranged on the upper surface or the lower surface of the midsole 21.

The thermoplastic polyester elastomer foam of the present invention constituting the shoe sole members 41 and 43 has a skin layer existing on one side or both sides, so that the mechanical strength such as the tensile strength of the foam and the surface strength such as abrasion resistance can be obtained. Further, since the load applied to the foam can be received on the surface, the load is dispersed, the foam is prevented from settling, and high impact resilience can be obtained. Further, since the thermoplastic polyester elastomer foam of the present invention constituting the sole members 41 and 43 has a crosslinked structure due to a siloxane bond, the compression set is small and good durability can be obtained.

The following thermoplastic polyester elastomer (TPEE), silane coupling agent, melt viscosity modifier, and silanolification accelerating catalyst were blended in FIGS. 3 and 4, pellets were prepared by a twin-screw extruder, and the prepared pellets were used. Each foam of Example 1 to Example 20 and Comparative Example 1 to Comparative Example 3 was produced by a supercritical gas injection molding method.

-TPEE-1 (thermoplastic polyester elastomer 1); product name: Perprene P-30B, manufactured by Toyobo Co., Ltd.-TPEE-2 (thermoplastic polyester elastomer 2); product name: Perprene P-40B, manufactured by Toyobo Co., Ltd.-Silane coupling agent- 1; 3-glycidoxypropyltriethoxysilane, product name: KBE-403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.-Silane coupling agent-2; 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; product name: KBM- 303, manufactured by Shin-Etsu Chemical Industry Co., Ltd. ・ Melt viscosity modifier; epoxy-modified styrene-acrylic copolymer, epoxy equivalent = 714, weight average molecular weight = 9700
・ Silanol conversion-promoting catalyst-1; dibutyltin diacetate, manufactured by Tokyo Chemical Industry Co., Ltd. ・ Silanolization-promoting catalyst-2; dibutyltin dilaurate, manufactured by Tokyo Chemical Industry Co., Ltd. ・ Physical foaming agent: nitrogen gas

The silanolization-promoting catalyst-1 and the silanolization-promoting catalyst-2 were used in a master batch using the same thermoplastic polyester elastomer as the main thermoplastic polyester elastomer to be blended. In the tables of FIGS. 3 and 4, the "resin component" in the columns of TPEE-1 and TPEE-2 indicates the ratio of the main TPEE used as the resin, while the "MB component" is the masterbatch silanolification promoting catalyst. The ratio of TPEE contained in is shown.

An electric injection molding machine is used as the injection molding machine, and the mold is configured so that the cavity between the movable mold and the fixed mold is 100 x 200 mm and the initial thickness can be changed from 0.5 mm to 5.0 mm. board.

Nitrogen gas is brought into a supercritical state using a supercritical supply device, then injected into the cylinder of an injection molding machine, and each component melted in the cylinder is set to a crystal melting point of 180 ° C. or higher, and the nitrogen gas is dispersed. It was melt-mixed. Then, it was injected into the cavity of the mold, then the movable mold was cored back, cooled, and then demolded to obtain a foam. The foam was immersed in warm water at 90 ° C. for 60 minutes and then taken out from the warm water to prepare samples of Examples 1 to 20 and Comparative Examples 1 to 3. In Examples 1 to 20, a thermoplastic polyester elastomer foam having an alkoxysilyl group was obtained by the demolding, and the obtained foam was immersed in warm water to obtain a thermoplastic polyester having a crosslinked structure due to a siloxane bond. An elastomer foam is obtained.

In Examples 1 to 4, TPEE-1 was used as the thermoplastic polyester elastomer, the ratio of the resin by the master batch was 10% (10 parts by weight), and the silane coupling agent-1 (3-glycidoxypropyltriethoxysilane). The compounding amount of the resin is 0.1 to 5 parts by weight, the compounding amount of the silanolification promoting catalyst-1 (dibutyltin diacetate) is 0.5 parts by weight, the initial thickness (initial thickness) of the cavity space is 2 mm, and the resin. Is 100% filled (full shot) with respect to the cavity volume, and then the mold is opened with a core back amount of 8 mm and immersed in warm water to have a crosslinked structure by siloxane bond and a closed cell structure having a skin layer on the surface. The thermoplastic polyester elastomer foam (foaming ratio 5 times) of the above was produced in a thickness of 10 mm. The weight of the resin to be filled was assumed to be 1, and the weight was converted into a volume, and the filling ratio (filling rate) with respect to the cavity volume was calculated.

In Example 5, 1 part by weight of each of silane coupling agent-1 (3-glycidoxypropyltriethoxysilane) and silane coupling agent-2 (2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane) was added. A thermoplastic polyester elastomer foam (foaming ratio 5 times) having a closed cell structure having a crosslinked structure by siloxane bond and a skin layer on the surface was produced in the same manner as in Example 1 except that it was blended, having a thickness of 10 mm. ..

In Examples 6 to 8, the ratio of the resin in the masterbatch was 2 to 30% (2 to 30 parts by weight), and the blending amount of silanolification promoting catalyst-1 (dibutyltin diacetate) was 0.1 to 1.5 weight by weight. A thermoplastic polyester elastomer foam (foaming ratio 5 times) having a closed cell structure having a crosslinked structure by a siloxane bond and a skin layer on the surface was produced in the same manner as in Example 1 except for the portion, having a thickness of 10 mm. bottom.

In Example 9, the ratio of the resin in the master batch was 20% (20 parts by weight), the blending amount of the silane coupling agent-1 (3-glycidoxypropyltriethoxysilane) was 1 part by weight, and the silanolization promoting catalyst-. It has a crosslinked structure by siloxane bond in the same manner as in Example 1 except that the blending amounts of 1 (dibutyltin diacetate) and silanolization promoting catalyst-2 (dibutyltin dilaurate) are 0.5 parts by weight each. A thermoplastic polyester elastomer foam having a closed cell structure having a skin layer on the surface (foaming ratio 5 times) was produced with a thickness of 10 mm.

In Examples 10 to 13, the blending amount of the silane coupling agent-1 (3-glycidoxypropyltriethoxysilane) was 1 part by weight, and the blending amount of the melt viscosity modifier was 0.05 to 1.5 parts by weight. A thermoplastic polyester elastomer foam (foaming ratio 5 times) having a crosslinked structure by a siloxane bond and a closed cell structure having a skin layer on the surface was produced in the same manner as in Example 1 except for the above.

In Example 14, TPEE-2 was used as the thermoplastic polyester elastomer, the ratio of the resin by the master batch was 10% (10 parts by weight), and the silane coupling agent-1 (3-glycidoxypropyltriethoxysilane) was blended. A thermoplastic polyester elastomer foam (foaming ratio 5 times) having a closed cell structure having a crosslinked structure by a siloxane bond and a skin layer on the surface was provided in the same manner as in Example 1 in an amount of 1 part by weight. Manufactured with a thickness of 10 mm.

In Example 15, 40 parts by weight of TPEE-1 as a thermoplastic polyester elastomer, 10 parts by weight as a resin obtained from the master batch thereof, 50 parts by weight of TPEE-2, and a silane coupling agent-1 (3-glycidoxypropyl). A thermoplastic polyester elastomer foam (foaming) having a closed cell structure having a crosslinked structure by a siloxane bond and a skin layer on the surface in the same manner as in Example 1 except that the blending amount of triethoxysilane) was 1 part by weight. (Magnification 5 times) was manufactured with a thickness of 10 mm.

Examples 16 to 20 are the same as in Example 1 except that the blending amount of the silane coupling agent-1 (3-glycidoxypropyltriethoxysilane) is 1 part by weight and the core back amount is 3 to 16 mm. A thermoplastic polyester elastomer foam (foaming ratio 2.5 to 9 times) having a closed cell structure having a crosslinked structure by a siloxane bond and a skin layer on the surface was produced with a thickness of 5 to 18 mm.

In Comparative Example 1, TPEE-1 was used as the thermoplastic polyester elastomer, no other components were blended, and the other components were a thermoplastic polyester elastomer foam having a closed cell structure having a skin layer on the surface in the same manner as in Example 1. Foaming ratio 5 times) was produced with a thickness of 10 mm.

In Comparative Example 2, TPEE-1 and TPEE-2 were used in combination as the thermoplastic polyester elastomer, no other components were blended, and the other components were thermoplastic having a closed cell structure having a skin layer on the surface in the same manner as in Example 1. A polyester elastomer foam (foaming ratio 5 times) was produced with a thickness of 10 mm.

In Comparative Example 3, TPEE-2 was used as the thermoplastic polyester elastomer, no other components were blended, and the other components were a thermoplastic polyester elastomer foam having a closed cell structure having a skin layer on the surface in the same manner as in Example 1. Foaming ratio 5 times) was produced with a thickness of 10 mm.

Density, impact resilience, and compression set were measured for each sample of each example and each comparative example, and the appearance was visually judged. The results are shown in FIGS. 3 and 4.
The density was measured based on JIS K 7222: 2005 by preparing a sample for measuring the density of diameter 29 mm × thickness of each sample from the samples of each Example and each Comparative Example. The sample for density measurement has skin layers on both sides.

As for the rebound resilience, when a sample for repulsion elasticity measurement of 100 mm square × thickness of each sample is prepared from the samples of each example and each comparative example by cutting, and the total thickness of the measurement samples is less than 10 mm, as in the case of density. A plurality of sheets were stacked to make 10 mm or more, and measurements were made based on JIS K 6400-3: 2011 (for each sample of Examples 16 to 18, two sheets were stacked so that the total thickness of the samples was 10 mm or more). The sample for measuring impact resilience has skin layers on both sides.

The compression set was measured as follows based on the JIS K6262: 2013 A method. First, a sample for compression permanent strain measurement was prepared by punching from the samples of each Example and each Comparative Example to a diameter of 29 mm, left to stand in an environment of a temperature of 23 ° C. and a humidity of 50% for 3 hours, and then for measurement using a caliper. The thickness h0 of the sample before the test was measured. The measurement sample is sandwiched between compression plates (compressors) made of two stainless steel plates in the thickness direction, compressed to a thickness of 50% of the thickness h0 before the test, and the temperature is 50 ° C. and the humidity is 50% in advance. The compression device containing the measurement sample was put into a constant temperature and humidity chamber maintained in the above state and allowed to stand for 6 hours. The thickness h2 of the spacer used at this time (thickness of 50% with respect to the thickness h0 of the measurement sample before the test) is measured. After 6 hours, the compression device was taken out from the constant temperature and humidity chamber, the compressed state was released, and the thickness h1 of the measurement sample after the test was measured after 30 minutes in an environment of a temperature of 23 ° C. and a humidity of 50%. The compression set was calculated according to the following equation.
Compressive permanent strain (%) = [(h0-h1) / (h0-h2)] × 100

As for the appearance, if the cell structure is non-uniform, voids and streaks appear on the surface, so if there are almost no voids or streaks on the appearance (when the cell structure is uniform), "○", a few voids or streaks When the cell structure is slightly uneven (when the cell structure is slightly uneven), it is evaluated as "Δ", and when many voids and streaks are observed (when the cell structure is extremely uneven), it is evaluated as "x".

Examples 1 to 20 have a density of 0.11 to 0.40 g / cm ³ , a rebound resilience of 63 to 74%, and a compression set of 19 to 34%, and are lightweight and have a high rebound resilience. Moreover, the compression set was small.
On the other hand, Comparative Examples 1 to 3 using only the thermoplastic polyester elastomer and not blending other components such as a silane coupling agent had the same density and impact resilience as those of Examples 1 to 20. The compression set was extremely large at 68 to 70%, and the compression set was large.

As described above, each embodiment is lightweight, has high impact resilience, and has a small compression set, and is suitable as a member for soles.
The sole member is not limited to the one provided on a part of the midsole, and may be provided on the entire surface or a wide range, or may be further provided on other sole constituent members.
In addition, the thermoplastic polyester elastomer foam of the present invention is used for various purposes other than shoe sole members, such as elastic feet (rubber) of various electric appliances such as furniture, home appliances, and office equipment, and various types of robots and machine tools. It can be used as a damper material for industrial machines.

The thermoplastic polyester elastomer foam of the present invention is subjected to a cross-linking treatment after obtaining the foam, and a cross-linking reaction does not occur in the grafting step or the foaming step. On the other hand, when cross-linking is carried out using peroxide, sulfur or the like, the cross-linking reaction may occur due to heating in the grafting step or the foaming step, and it is difficult to control the cross-linking reaction. When a cross-linking reaction occurs in the grafting step or the foaming step, the entire matrix is cross-linked, and the molding itself of the thermoplastic polyester elastomer cannot be performed.

10 Shoes 21 Midsole 41, 43 Sole member

Claims (4)

In thermoplastic polyester elastomer foam
The thermoplastic polyester elastomer foam has a crosslinked structure due to a siloxane bond, and has a crosslinked structure.
Consists of a closed cell structure with skin layers on one or both sides
A thermoplastic polyester elastomer foam having a compression set of 50% or less. The thermoplastic polyester elastomer foam according to claim 1, wherein a melt viscosity modifier is added to the thermoplastic polyester elastomer foam. The thermoplastic according to claim 1 or 2, wherein the thermoplastic polyester elastomer foam is provided as a member for the sole of the foot at a portion corresponding to a stepping portion and a heel portion of the sole of the foot. Polyester elastomer foam. The thermoplastic polyester elastomer foam according to any one of claims 1 to 3, wherein the foaming ratio of the thermoplastic polyester elastomer foam is 2.5 to 10 times.

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