CN115260643B

CN115260643B - Fatigue-resistant midsole foam material, preparation method and sports shoes

Info

Publication number: CN115260643B
Application number: CN202210982707.1A
Authority: CN
Inventors: 雷世源; 丁世家
Original assignee: Anta China Co Ltd
Current assignee: Anta China Co Ltd
Priority date: 2022-08-16
Filing date: 2022-08-16
Publication date: 2023-07-04
Anticipated expiration: 2042-08-16
Also published as: CN115260643A

Abstract

The invention provides a fatigue-resistant midsole foaming material, a preparation method and sports shoes, wherein the midsole foaming material is prepared by blending and foaming EVA materials, the EVA materials comprise 10-25 parts of self-repairable organosilicon elastomer materials, 40-60 parts of EVA, 10-20 parts of polyolefin elastomers, 5-10 parts of EPDM (ethylene-propylene-diene monomer), 5-25 parts of styrene polymers, 0.6-0.7 part of peroxide cross-linking agents, 2.5-3.5 parts of foaming agents, 0.5-1.5 parts of zinc oxide, 0.5-1.5 parts of stearic acid, 0.5-1.5 parts of zinc stearate and 2-5 parts of aminosilane coupling agents; the organic silicon elastomer material is prepared by reacting amino-terminated polydimethylsiloxane with diisocyanate and thiocarbonyl diimidazole. The insole material for the sports shoes has small performance attenuation after long-time use, good self-repairing property and capability of improving the fatigue resistance and the service life of the sports shoes.

Description

Fatigue-resistant midsole foam material, preparation method and sports shoes

Technical Field

The invention belongs to the technical field of footwear products, and particularly relates to a fatigue-resistant midsole foam material, a preparation method thereof and a sports shoe, namely a preparation method and an implementation method of a self-repairing midsole foam material.

Background

It is known that the bottom of a sports shoe is subject to local damage or microcracking inside the foamed midsole material due to prolonged stress during movement or prolonged wear by consumers, which can result in a reduction in various properties of the sports shoe. Regarding the life problem of athletic shoes, running equipment has an internationally recognized life span of athletic shoes, i.e., 500-1000 km of wear. Assuming a running sports shoe with a service life of 800 km, the service life of the pair of running shoes is 8 months for a runner running a month at a distance of 100 km. Of course, this is the net life calculated ignoring the individual's constitution, running habits, training patterns, and the like. And various performances of the sole can be gradually attenuated along with the increase of the mileage. Generally, after the running amount of a pair of running shoes reaches 80 km, the damping and cushioning effect of the soles is only 75% of the original damping and cushioning effect; when the distance reaches about 200 km, the damping effect is about 65% of the original damping effect; when the running amount reaches 400-800 km, the damping effect is less than 60%.

It has been investigated that as athletic shoes wear for a long period of time, resulting in a reduction in sole performance, the foamed midsole begins to become stiff, flat and less flexible, which not only affects the consumer's wearing experience, but also affects the consumer's athletic safety and physical health problems. The reason is mainly that: the weakening of the shock absorption performance of the sole can lead to the increase of reaction force in the movement process, and the damage to bones and joints can be caused. Conventional EVA, POE, OBC, EPDM, SEBS and other polymers are used for preparing middle bottom parts of sports shoes through chemical foaming, and the middle bottom parts belong to thermosetting crosslinking technology, and a network structure formed after crosslinking leads to the loss of fluidity of molecular chains, so that the material structure is irreversibly damaged after long-time use.

Accordingly, there is a need for a pair of athletic shoes that are durable and stable in performance and have a longer wear life.

Disclosure of Invention

In view of the above, the invention aims to provide a fatigue-resistant midsole foam material, a preparation method and a sports shoe.

The invention provides a fatigue-resistant midsole foam material which is prepared by blending and foaming EVA materials, wherein the EVA materials comprise the following components in parts by weight:

10-25 parts of self-repairable organic silicon elastomer material, 40-60 parts of ethylene-vinyl acetate copolymer, 10-20 parts of polyolefin elastomer, 5-10 parts of ethylene propylene diene monomer rubber, 5-25 parts of styrene polymer, 0.6-0.7 part of peroxide cross-linking agent, 2.5-3.5 parts of foaming agent, 0.5-1.5 parts of zinc oxide, 0.5-1.5 parts of stearic acid, 0.5-1.5 parts of zinc stearate and 2-5 parts of aminosilane coupling agent;

the self-repairable organic silicon elastomer material is mainly prepared by the reaction of amino-terminated polydimethylsiloxane, diisocyanate and thiocarbonyl diimidazole; the vinyl acetate structure content of the ethylene-vinyl acetate copolymer is 18-38 wt%.

The embodiment of the invention discloses a preparation and realization method of a self-repairable sports shoe midsole foaming material, which adopts a self-repairable organosilicon elastomer material generated by the reaction of amino polysiloxane, diisocyanate and thiocarbonyldiimidazole, and the self-repairable sports shoe midsole foaming material is obtained by blending and foaming the self-repairable organosilicon elastomer material with EVA/POE/EPDM/SEBS and other components. The foam material meets the performance requirements of the middle sole of the sports shoe, and meanwhile, the performance attenuation of the middle sole of the sports shoe after long-time use can be improved by means of the combined action of hydrogen bonds and imine bonds with different strengths in the self-repairing organic silicon elastomer material, so that the fatigue resistance and the service life of the sports shoe are greatly improved.

The self-repairable midsole foam material is also called a fatigue-resistant midsole foam material, and is prepared by blending EVA materials and foaming. The EVA material provided by the invention takes ethylene-vinyl acetate copolymer as a main polymer raw material, and specifically comprises 40-60 parts by weight of EVA, for example 40 parts, 45 parts, 50 parts, 55 parts and the like.

The ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer, and is called EVA for short. The EVA material comprises the following components: EVA with the mass ratio of Vinyl Acetate (VA) of 18-38%, wherein the VA structure content is preferably 20-28wt%, and the elasticity, flexibility and the like of the foaming material are facilitated. In a preferred embodiment of the invention, commercially available EVA varieties are: EVA7360M, and/or EVA7470M (Table Plastic Co.).

The EVA material provided by the invention comprises the following raw materials in parts by weight: 10-20 parts of polyolefin elastomer (POE), 5-10 parts of Ethylene Propylene Diene Monomer (EPDM) and 5-25 parts of styrene polymer.

Wherein, POE of the embodiment of the invention mainly comprises ethylene-octene copolymer; the preferred varieties are: POE 8180, and/or POE8150, further POE 8180 (crystallinity 16%, product of Dow company) can improve the impact resistance and other properties of the middle-substrate material.

The ethylene propylene diene monomer is a terpolymer synthesized by monomer ethylene, propylene and non-conjugated diene, and is EPDM for short, so that the aging resistance and the like are good. In a preferred embodiment of the present invention, the crystallinity of the ethylene propylene diene monomer is not more than 15%, for example, 5 parts by mass of EPDM is used. The EPDM is a commercial brand product with crystallinity less than or equal to 15%, and the preferable varieties are as follows: EPDM 5565, EPDM 3745 (crystallinity 12%, dow company).

The styrene polymer is a segmented copolymer formed by polymerizing monomers such as styrene (S), wherein the mass content of the styrene structure is preferably 13-33%. The EVA material preferably comprises 5-20 parts of styrene polymer, which can be selected from one or more of styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-butylene-styrene copolymer (SBBS) and hydrogenated styrene-butylene elastomer (SOE) with high vinyl content, so as to be beneficial to obtaining the foamed midsole material with good comprehensive properties of hardness, strength and the like. Preferably, the brand varieties are babin petrochemical company SEBS YH688 (s=13%), asahi chemical company SBBS J1083 (s=20%), SOE L609 (s=33%).

In the polymer raw material system, 10-25 parts of self-repairable organic silicon elastomer material is mainly added to realize the self-repairability or fatigue resistance of the midsole foaming material. Specifically, the self-repairable organosilicon elastomer material is formed by reacting amino-terminated polydimethylsiloxane with diisocyanate and thiocarbonyl diimidazole. Meanwhile, the EVA material comprises: 2-5 parts of an aminosilane coupling agent.

In the self-repairable organic silicon elastomer material, amino groups in polysiloxane react with isocyanate to form ureido groups and form strong hydrogen bonds, and the amino groups react with thiocarbonyldiimidazole to form weak hydrogen bonds in microscopic principle. Through the strong and weak coordination action of the hydrogen bond, the regular structure of the hydrogen bond is destroyed, and the energy barrier required by the hydrogen bond complexing-decomplexing process is reduced, so that the thermal reversibility at room temperature without high-temperature heating can be realized. In addition, the reaction of amino and aldehyde groups generates imine bonds, which can enhance the self-repairing capability of the material. In the invention, the combined action of hydrogen bonds with different strengths and imine bonds carries out molecular chain diffusion, reconnection entanglement and crosslinking under the multiple reversible actions of a plurality of functional sites, so that a new dynamic network structure is formed to reunite microcrack positions together, and the microcrack repair is completed, thereby realizing the self-repair of the foaming material.

The modified silicone elastomer materials described above in embodiments of the present invention may be commercially available, for example, room temperature self-healing products having a hardness of 25A. Although the organic silicon elastomer material has excellent self-repairing performance, the organic silicon elastomer material has low mechanical strength and melt strength, and cannot be independently foamed into the middle sole of the sports shoe. According to the technical scheme, the EVA-based foaming agent is used as a functional material to be added into the EVA-based foaming formula, and 10-25 parts of self-repairable organic silicon elastomer material is added into the foaming midsole material, so that each performance of the foaming midsole material meets the performance requirement of the middle sole of the sports shoe, and good self-repairability can be exerted at room temperature. If too much is added, the performance is also affected, and the method is not suitable for being applied to the sports shoe industry.

In an embodiment of the present invention, the aminosilane coupling agent is 2 to 5 parts, preferably comprising: gamma-aminopropyl triethoxysilane (KH 550, KH-550), aminopropyl trimethoxysilane (KH 551), a further preferred variety is KH550.

In the embodiment of the invention, the peroxide crosslinking agent is 0.6-0.7 part and can be one or more selected from dicumyl peroxide and 1, 4-di-tert-butyl peroxyisopropyl benzene, and the commercial varieties are DCP and BIBP. The foaming agent is 2.5-3.5 parts, and can be selected from one or more of azodicarbonamide, 4-oxo diphenyl sulfonyl hydrazine and sodium bicarbonate, preferably azodicarbonamide, and the commercial varieties are as follows: AC6000H.

In addition, the EVA material provided by the invention comprises the following components: zinc oxide 0.5-1.5 parts, preferably 1 part, stearic acid 0.5-1.5 parts, preferably 1 part, and zinc stearate 0.5-1.5 parts, preferably 1 part, can play roles in lubrication, promotion of crosslinking foaming, and the like.

In the embodiment of the invention, the hardness of the midsole foaming material is 40-48 ℃, the rebound is over 42%, the midsole foaming material can be self-repaired at room temperature, and the fatigue resistance is excellent. The midsole foaming material can exert good self-repairing property at room temperature without high-temperature heating or external force action in the self-repairing process, and the retention rate of each performance after 12 hours of self-repairing can reach more than 80 percent. In addition, the repairing process is convenient and quick, and the repairing method is pioneered in the industry.

The invention provides a preparation method of the midsole foaming material, which comprises the following steps: according to the weight ratio, the materials are mixed and granulated, and the fatigue-resistant midsole foaming material is obtained through a foaming molding process. In some embodiments of the present invention, the foam molding process is specifically: foaming and vulcanizing the material obtained by granulation, and then baking to obtain the midsole foaming material; or, carrying out small foaming on the material obtained by granulation, and then carrying out secondary compression molding to obtain the midsole foaming material.

The embodiment of the invention is mainly suitable for two processes of primary injection molding (IP process) or secondary compression molding (MD process) to prepare the midsole foaming material.

As shown in fig. 1, the IP process includes the steps of weighing, mixing, granulating, foaming and vulcanizing, and baking.

According to the embodiment of the invention, the materials are weighed according to the dosage of the formula: the DCP and the foaming agent can be weighed as a first group; weighing stearic acid, zinc stearate and zinc oxide as a second group; the remaining materials were weighed for the third group.

The mixing process of the embodiment of the invention comprises the following steps: firstly, pouring the third group of materials into an internal mixer, starting the internal mixer, and pouring the second group of materials when the temperature is raised to 80-85 ℃; pouring the first group of materials when the temperature is increased to 90-95 ℃; and pouring out the mixed materials when the temperature is raised to 100-110 ℃.

After mixing, the mixed materials are poured into a material making machine for granulation, and in the specific process, the temperatures of the first, second, third and fourth areas are preferably respectively adjusted to be: 75. 80, 85, 90 ℃; and the screw is adjusted to 40-50 rpm, and the blanking is adjusted to 15-20 rpm.

The foaming vulcanization preferably comprises: pouring the manufactured materials into an injection foaming molding machine, and respectively adjusting the temperatures of a first area, a second area, a third area and a fourth area of feeding to be: 80. the temperatures of the upper template and the lower template of the forming die are respectively adjusted to be 85 ℃, 90 ℃ and 95 ℃: 170. 170 ℃. The amount of the materials is set according to the amount of the mold, and the vulcanizing time can be 500-700 seconds.

Finally, baking is carried out according to the embodiment of the invention: the temperatures of the first, second, third and fourth zones of the oven are preferably respectively adjusted to be: 80. the rotation speed is 60-70 rpm at 90, 95 and 100 ℃; and (3) sending the foaming material subjected to foaming molding into an oven port, wherein the length of the oven is preferably 30-40 m, and the baking time is preferably 30-40 min, so that the fatigue-resistant midsole foaming material is obtained.

As shown in FIG. 2, the MD process comprises the following steps of weighing, mixing, granulating, small foaming and secondary compression molding. The specific process steps are as follows:

weighing: weighing a cross-linking agent and a foaming agent into a first group according to the dosage of the formula; weighing zinc oxide, stearic acid and zinc stearate as a second group; the remaining materials were weighed for the third group.

Mixing: firstly, pouring the third group of materials into an internal mixer, starting the internal mixer, and pouring the second group of materials when the temperature is increased to 75-85 ℃; pouring the first group of materials when the temperature is raised to 85-95 ℃; and pouring out the mixed materials when the temperature is raised to 100-105 ℃.

Granulating: pouring the mixed materials into a material making machine, and respectively adjusting the temperatures of the first, second, third and fourth areas to be: 75. 80, 85, 90 ℃; and the screw is adjusted to 40-50 rpm, and the blanking is adjusted to 15-20 rpm.

Small foaming: pouring the manufactured granules into a flat-plate mould pressing small foaming mould to finish the first foaming; the foaming temperature can be 170-175 ℃ and the foaming time is 600-660 seconds.

Secondary compression molding: and (3) standing and cooling the small-foamed semi-finished product for 24 hours, and pressing the small-foamed semi-finished product into a flat plate mould pressing mould to finish finished product mould pressing, thereby obtaining the midsole foaming material. Further preferably, the hot pressing temperature is 175 ℃; the hot pressing time is 420 seconds; the cooling water temperature is 25 ℃; the cooling time was 420 seconds.

The invention provides a sports shoe, which adopts the midsole foaming material as a midsole component. The structure (including thickness, overall shape, ground contact structure, etc.), and other accessories are not particularly limited, and may be conventional in the art.

The self-repairing midsole foam material provided by the embodiment of the invention is subjected to an anti-fatigue test (the selection force value is 1300N test mode, the compression time is 10 ten thousand times, the test speed is 120 times/min), and a self-repairing test (a compressed sample is taken from equipment after the compression test is finished and placed in a constant temperature environment of 23+/-2 ℃ for 12 hours), and the rebound rate, the delamination tearing strength, the compression deformation, the tensile strength and the retention rate of dynamic rigidity are more than 80% when being compared with the performances of the foam material before and after the anti-fatigue test and after the self-repairing. Therefore, by introducing the self-repairing organic silicon elastomer material, the embodiment of the invention improves various performance attenuations generated after the sole of the sports shoe moves for a long time, thereby improving the long-term use stability of the midsole of the sports shoe and prolonging the service life of the sports shoe.

Drawings

FIG. 1 is a schematic diagram of an IP process flow according to some embodiments of the invention;

FIG. 2 is a schematic diagram of an MD process flow diagram according to some embodiments of the present invention;

fig. 3 is a photograph of a finished midsole foam material of example 1 of the present invention.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully, and it is apparent that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

The present invention is not limited by the following examples, and the specific embodiments can be determined according to the technical solutions and practical situations of the present invention described above. The invention will be further illustrated with reference to specific examples. In the following examples, each of the raw materials was a commercially available product.

Example 1

Weighing the cross-linking agent and the foaming agent into a first group according to the dosage of the formula in the table below; weighing zinc oxide, stearic acid and zinc stearate as a second group; the remaining materials were weighed for the third group.

Firstly, pouring the third group of materials into an internal mixer, starting the internal mixer, and pouring the second group of materials when the temperature is increased to 75-85 ℃; pouring the first group of materials when the temperature is raised to 85-95 ℃; and pouring out the mixed materials when the temperature is raised to 100-105 ℃.

Pouring the mixed materials into a material making machine, and respectively adjusting the temperatures of the first, second, third and fourth areas to be: 75. 80, 85, 90 ℃; and the screw is adjusted to 40-50 rpm, and the blanking is adjusted to 15-20 rpm.

Pouring the manufactured granules into a flat mould pressing small foaming mould (a common mould), and finishing the first foaming, wherein the foaming temperature is as follows: 170-175 ℃; the foaming time is as follows: 600-660 seconds.

And (3) standing and cooling the small-foamed semi-finished product for 24 hours, and pressing the small-foamed semi-finished product into a flat plate die-pressing die to finish the die-pressing of the finished product, thereby obtaining a finished product of the midsole foam material (the physical diagram of the midsole part is shown in a picture of fig. 3). The molding process comprises the following steps: the hot pressing temperature is as follows: 175 ℃; the hot pressing time is as follows: 420 seconds; the cooling water temperature is: 25 degrees; the cooling time is as follows: 420 seconds.

Comparative examples 1 to 8

According to the amounts of the formulations shown in the following table, corresponding midsole materials were obtained according to the process steps of example 1, respectively.

Examples 2 to 12

According to the amounts of the formulations shown in the following table, corresponding midsole materials were obtained according to the process steps of example 1, respectively. The above midsole foam material samples were subjected to performance testing, with the following results.

Table 1 formulations of comparative examples 1-8

Table 2 formulations of examples 1-8

Table 3 formulations of examples 9-12

Composition of the composition	Example 9	Example 10	Example 11	Example 12
					Self-repairing silicon material 2	20	20	20	20
EVA 7360M	50	50	45	40
					POE 8180	15	10	10	20
EPDM 3745	5	5	5	5
					SEBS J1083	10	-	-	-
SEBS YH688	-	-	20
					SOE L609	-	15	-	15
KH 550	4	4	4	4
					AC6000H	3.5	3.5	2.7	2.7
DCP	0.65	0.65	0.65	0.65
					Stearic acid 1801	1.0	1.0	1.0	1.0
Zinc stearate	1.0	1.0	1.0	1.0
					ZnO 997	1.0	1.0	1.0	1.0

Wherein, the specific content of the raw materials of the formula is as follows:

self-repairing silicon material 1: organosilicon self-repairing material containing pyridine group with hardness of 30A and self-repairing temperature of 80-120 deg.C is believed to be company.

Self-repairing silicon material 2: the organosilicon elastomer material produced by the reaction of the amino-terminated polysiloxane, diisocyanate and thiocarbonyldiimidazole has the hardness of 25A and the self-repairing temperature of 20-35 ℃ and is available from Dow Corning company.

EVA7360M: hardness 86A, VA content 21%, crystallinity 32.1%, table Plastic Co.

POE 8180: hardness 63A, ethylene-octene copolymer, crystallinity 16%, dow company.

EPDM 3745: ethylene propylene diene monomer, mooney viscosity 45 (ML 1+4/125 ℃), crystallinity 12%, ethylene content 70%, dow company.

SEBS YH688: hardness 43A, S13%, baling petrochemical.

SEBS J1083: hardness 56A, S content 20%, xuehua chemical company.

SOE L609: hardness 76A, S content 33%, xuehua chemical company.

ZnO 997: white stone brand zinc oxide with a relative density of 4.42-4.45 and macrocypress chemical technology Co.

KH 550: chemical industry of Kaiyin Shanghai.

DCP: chinese petrochemical industry.

Stearic acid 1801: indonesia Du Kuda.

Zinc stearate: the new chemical company of water chestnut lake in Huzhou city is expected.

The foaming agent is AC6000H (azodicarbonamide): hangzhou sea iridescence fine chemical Co., ltd.

Table 4 comparative examples 1-3 test performance data sheet

Table 5 comparative examples 4-6 test performance data sheet

Table 6 comparative examples 7-8 and example 1 test performance data sheet

Table 7 examples 2-4 test performance data sheet

Table 8 examples 5-7 test performance data sheet

Table 9 examples 8-10 test performance data sheet

Table 10 examples 11-12 test performance data table

Remarks:

(1) GB/T38018-2019: test method of sole of footwear fatigue resistance test: the test mode with the force value of 1300N is selected, the dynamic compression time is 10 ten thousand times, the test speed is 120 times/min, and the thickness of a tested foaming test piece is 20mm.

(2) Room temperature self-repairing method: after the compression test is finished, the compressed sample is taken out from the equipment and placed under the constant temperature (23+/-2 ℃) environment condition and kept stand.

(3) The performance data after fatigue and after self-repair are both tested within 1h after the test is finished.

(4) Hardness test standard: DIN 55305;

(5) Density test standard: DIN 53479;

(6) Rebound test criteria: DIN 53512;

(7) Delamination tear test criteria: DIN 53507-B;

(8) Tensile strength test standard: DIN 53543;

(9) Compression set test standard: ASTM-D.395-B;

(10) Dynamic stiffness dsii test standard: ASTM F1614-99.

(11) The comparative examples and examples in the present invention were prepared uniformly using the MD process.

From the test results of the comparative examples and the examples, it can be seen that after the midsole foam material is subjected to fatigue resistance test, various properties are changed, such as: the density and the hardness are increased, the dynamic rigidity DS II is increased, and the rebound, the delamination tearing, the tensile strength and the compression deformation are all poor. An increase in density and hardness indicates a gradual stiffening of the sole and a decrease in flexibility; an increase in dynamic stiffness dsii and a decrease in rebound can affect the feel of the foot when the consumer is dynamically wearing; deterioration of performances such as layered tearing, tensile strength, compression deformation and the like represents reduction of mechanical properties of the sole, and influences the wearing life of the foamed midsole.

From the test results of comparative examples 1, 2, it is seen that: after fatigue resistance experiments, the foam test piece without self-repairing organic silicon materials is kept stand for 12 hours at room temperature, and all performance data are basically unchanged, which shows that the thermosetting crosslinking technology based on the traditional foam midsole is used, and the network structure formed after crosslinking leads to the loss of fluidity of molecular chains, so that the material structure is irreversibly damaged and cannot be self-repaired, and therefore, the fatigue resistance of the traditional sports foam midsole is poor.

From comparison of the self-repairing test results of comparative examples 3 to 6, it can be seen that: if a material which can be self-repaired at high temperature is added into the formula, the self-repairing capability at room temperature is extremely weak, and the individual performance data are improved compared with the data after the fatigue resistance test, but the self-repairing effect is very little. This is also one of the reasons for the selection of materials that can be self-healing at room temperature.

From the test data of examples 1-12, it can be seen that: the organic silicon self-repairing material is added into the high-elastic foaming material (examples 1-4), the damping foaming material (examples 5-8), the light foaming material (examples 9-10) and the soft elastic foaming material (examples 11-12), so that a good self-repairing effect can be generated, and the performance retention rate of each performance can reach more than 80%.

From comparison of the test results of comparative examples 7 to 8 and examples 1 to 4, it can be seen that: after 30 parts of organic silicon self-repairing material is added, the self-repairing effect is still excellent, but the initial mechanical property is reduced more; after 5 parts of organic silicon self-repairing material is added, the self-repairing capability of the midsole foaming material is insufficient, so that 10-25 parts of organic silicon self-repairing material is preferably added, the influence on various mechanical properties is small, and the obtained self-repairing effect is good.

Further, it can be seen from the repair effect at different repair times of example 11: the repair time is 3-6h, and the repair of each performance is insufficient; the repair time is prolonged to 12 hours, and the data of each performance is close to the performance data before fatigue, which shows that the repair effect is excellent; and further prolonging the repairing time to 24 hours, wherein the data of each performance is very similar to the performance data of repairing 12 hours, which indicates that the optimal repairing time of the self-repairing midsole foaming material is about 12 hours.

In summary, compared with the existing foaming midsole material, the functional self-repairing material is introduced into the foaming material of the midsole of the sports shoe, so that the problem that the existing foaming midsole cannot be self-repaired is solved, various performance attenuations generated after the sports shoe sole moves for a long time are improved, the fatigue resistance and the service life of the midsole of the sports shoe are greatly improved, and the foaming midsole of the sports shoe belongs to the initiative in the industry.

For the self-repairing midsole foaming material provided by the embodiment of the invention, a good self-repairing effect can be generated no matter the self-repairing midsole foaming material is a high-elastic foaming formula, a damping foaming formula, a light foaming formula and a soft elastic foaming formula, and after 12h self-repairing, the retention rate of each performance can reach more than 80%. Therefore, the sports shoes suitable for application have wide range and extremely high application value and application prospect.

The self-repairing midsole foaming material can exert good self-repairing property at room temperature, and high-temperature heating, infrared irradiation or external force action is not needed in the self-repairing process. When the self-repairing agent is applied to the middle sole of the sports shoe, after a consumer wears the sports shoe, the self-repairing agent is naturally placed, and the self-repairing agent in the foaming sole can generate a deliberate self-repairing effect, so that the self-repairing process is very convenient and quick.

The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the method of the present invention and its core ideas. The foregoing is merely illustrative of the preferred embodiments of this invention, and it is noted that there is objectively no limit to the specific structure disclosed herein, since numerous modifications, adaptations and variations can be made by those skilled in the art without departing from the principles of the invention, and the above-described features can be combined in any suitable manner; such modifications, variations and combinations, or the direct application of the inventive concepts and aspects to other applications without modification, are contemplated as falling within the scope of the present invention.

Claims

1. The fatigue-resistant midsole foam material is characterized by being prepared by blending and foaming EVA materials, and the EVA materials comprise the following components in parts by weight:

the self-repairable organic silicon elastomer material is prepared by reacting amino-terminated polydimethylsiloxane with diisocyanate and thiocarbonyl diimidazole; the vinyl acetate structure content of the ethylene-vinyl acetate copolymer is 18-38wt%; the styrene polymer is selected from one or more of styrene-ethylene-butylene-styrene copolymer, styrene-butylene-styrene copolymer and hydrogenated styrene-butylene elastomer with high vinyl content; the hardness of the midsole foaming material is 40-48 ℃, and the midsole foaming material can be self-repaired at room temperature.

2. The midsole foam material of claim 1, wherein the ethylene propylene diene monomer rubber has a crystallinity of no more than 15%.

3. The midsole foam according to any one of claims 1-2, wherein the peroxide crosslinking agent is selected from one or more of dicumyl peroxide and 1, 4-bis-t-butylperoxycumene.

4. A midsole foam according to claim 3, wherein the foaming agent is selected from one or more of azodicarbonamide, 4-oxo-diphenyl sulphonyl hydrazide and sodium bicarbonate.

5. The midsole foam of claim 4, wherein the midsole foam has a rebound of 42% or greater.

6. The method for preparing the midsole foam material according to any one of claims 1 to 5, comprising the steps of: according to the weight ratio, the materials are mixed and granulated, and the fatigue-resistant midsole foaming material is obtained through a foaming molding process.

7. The preparation method according to claim 6, wherein the foaming molding process specifically comprises: foaming and vulcanizing the material obtained by granulation, and then baking to obtain the midsole foaming material; or, the material obtained by granulation is subjected to small foaming, and then is subjected to secondary compression molding, so that the midsole foaming material is obtained.

8. An athletic shoe employing the midsole foam material of any one of claims 1-5 as a midsole component.