Multilayer composite material and its forming method and application

Abstract

The application discloses a kind of multilayer composite material and its forming method and application, it is related to high polymer material technical field, the optimized high-heeled shoe material is obtained by optimizing buffer material layer in the present application, and provide relatively fast forming method, and can have good application in high-heeled shoe.Especially provide a kind of vamp structure for protecting ankle tendon, can stabilize the high-heeled shoe of ankle.The present application is better by structure design and material upgrading, the foot is coated, the foot movement form is adjusted, and the motion stability is improved, to improve the comfort degree of wearing high-heeled shoe.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a multilayer composite material, its molding method, and its application. Background Technology

[0002] High heels are an important category of women's shoes and a frequently seen type of clothing in modern society. High heels mainly consist of an upper, a sole, and a heel. The upper is attached to the sole by adhesive or stitching, while the heel is fixed to the sole near the back using rivets or adhesive. Their defining characteristic is the high heel, which not only increases height but also enhances the overall silhouette by altering posture.

[0003] However, on the other hand, as heel height increases, comfort gradually decreases, especially during prolonged walking and standing, leading to leg pain, lower back pain, and other problems. A key reason for this is that when wearing high heels, the body's center of gravity shifts forward compared to standing in flat shoes, increasing the weight supported by the forefoot by 10-20%. This is especially true for heels with heels over 8 centimeters, where most of the weight falls on the forefoot. This not only demands greater forefoot strength but also places higher demands on the surrounding auxiliary stabilizing muscles such as the ankle and heel. Particularly during exercise, insufficient strength in the foot's stabilizing muscles leads to compensatory stability from other muscle groups, resulting in a series of problems such as leg pain, lower back pain, and back pain.

[0004] In conclusion, while high heels, especially those with heels over 8 centimeters, enhance the aesthetics and temperament of the wearer's attire, they also bring a poor wearing experience, thus limiting the use and development of high heels. Summary of the Invention

[0005] This invention addresses the problems existing in the prior art by providing a multilayer composite material, its molding method, and its application in high heels. Through material upgrades and upper structure design, it better covers the foot, adjusts the foot's movement pattern, improves movement stability, protects ankle tendons, and enhances the comfort of wearing high heels.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a multilayer composite material comprising a base layer, a first adhesive layer, a polyurethane microfoam layer, a second adhesive layer, and an ankle contact layer, wherein the polyurethane microfoam layer is a polyurethane microfoam material with a density of 0.26-0.36 g / cm³. 3The ASKER C hardness is 20-36; the first and second adhesive layers are made of polyurethane adhesive, the base layer is natural leather and / or artificial leather, and the ankle contact layer is natural leather and / or artificial leather.

[0007] Furthermore, the polyurethane microfoam layer material is a polycondensation product of 100 parts by weight of hydroxyl-terminated polyepoxychloropropane and 50-70 parts by weight of PAPI isocyanate.

[0008] Furthermore, the hydroxyl-terminated polyepoxychloropropane is a cross-linked ring-opening polymerization product of four-arm polyethylene glycol and epichlorohydrin under boron trifluoride catalysis.

[0009] Furthermore, the structure of the terminal hydroxyl polyepoxychloropropane is as shown in structural formula (I): (I) Wherein, a, b, m, n represent the number of repeating units in the polymer, and the number-average molecular weight of the terminal hydroxyl polyepoxychloropropane is 10500.

[0010] Furthermore, the viscosity of the terminal hydroxyl polyepoxychloropropane is 1.2 Pa•s.

[0011] Further, the preparation method of the polyurethane microfoam layer material includes: mixing 100 parts by weight of hydroxyl-terminated polyepoxychloropropane with 30-50 parts by weight of plasticizer, 20-40 parts by weight of 5613 polyether polyol, and 0.1-0.15 parts by weight of stannous octoate evenly, and adding 50-70 parts by weight of PAPI isocyanate to obtain a precursor to be molded; adding the precursor to be molded into a mold and curing it at a temperature of 50-80℃ for 10-20 hours to obtain the polyurethane microfoam material; wherein the plasticizer is castor oil.

[0012] Furthermore, multilayer composite materials can also include other functional layers such as protective layers and breathable layers, which play a role in protection, breathability, reducing damage, and improving product life.

[0013] Secondly, the present invention also provides a molding method for the above-mentioned multilayer composite material, comprising the following steps: Mix 100 parts by weight of hydroxyl-terminated polyepoxychloropropane with 30-50 parts by weight of plasticizer, 20-40 parts by weight of 5613 polyether polyol, and 0.1-0.15 parts by weight of stannous octoate. Add 50-70 parts by weight of PAPI isocyanate to obtain the precursor to be molded. A polyurethane adhesive is applied to the surface of the base layer and left for 30-180 seconds to form a first adhesive layer. The precursor to be molded is then applied to the surface of the first adhesive layer, and a polyurethane adhesive is applied to the surface of the precursor to be molded to form a second adhesive layer. An ankle contact layer is then covered on the surface of the second adhesive layer, and the mixture is placed in a mold and molded for 10-20 hours to obtain a multilayer composite material.

[0014] Furthermore, before the surface of the substrate is coated with polyurethane adhesive, it is impregnated with polyether polyol and / or polyester polyol.

[0015] Furthermore, the molding temperature in the mold is 50-80℃.

[0016] Thirdly, the present invention also provides the application of any of the above-mentioned multilayer composite materials in high heels.

[0017] Fourthly, the present invention also provides a shoe upper structure for protecting ankle tendons, which adopts any of the above-mentioned multi-layer composite materials, wherein the shoe upper structure is arc-shaped and the thickness of the multi-layer composite material is 1-3mm.

[0018] Fifthly, the present invention also provides a high heel shoe, wherein the heel counter includes the aforementioned shoe upper structure for protecting the ankle tendons, the shoe upper structure is disposed at a corresponding position in contact with the rear ankle, the shoe upper structure extends upward to the heel opening and downward to the heel end point of the shoe upper, the height H between the heel end point of the shoe upper and the horizontal line of the heel sole is 17-35mm, the angle α between the arcuate tangent line of the heel sole at 2 / 3 of the height from the end of the heel opening and the vertical line is 11-36 degrees, preferably 12-35 degrees, and the angle β between the arcuate tangent line of the heel opening and the horizontal plane is 58-76 degrees.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The multilayer composite material provided by this invention, preferably made of polyurethane, offers an optimized performance range. While ensuring cushioning and abrasion resistance, it provides sufficient grip to the ankle, improving ankle stability and reducing ankle swaying during walking. This reduces compensation from the body's stabilizing muscles and lowers fatigue, thus minimizing damage caused by high heels. This performance surpasses that of commonly available elastic and cushioning materials, such as sponges.

[0020] The molding method for multilayer composite materials provided by this invention can quickly add a cushioning and protective layer to the shoe upper, resulting in a product with good stability. It can be completed at room temperature, reducing the impact and damage to the shoe upper material.

[0021] The shoe upper structure provided by this invention protects the ankle tendons. By optimizing the shoe upper design, it adjusts the foot posture when standing and walking, reducing compensation from the body's stabilizing muscle groups. This reduces acute or cumulative damage to the body caused by incorrect walking posture.

[0022] The high heels provided by this invention, by adjusting the heel angle design, increase the shoe upper's coverage of the foot, making the shoes fit the foot better, improving the stability of the shoes when walking, and reducing the fatigue caused by wearing high heels. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0024] Figure 1 This is a schematic diagram of the structure of a multilayer composite material provided in an embodiment of the present invention.

[0025] Figure 2 This is a structural diagram of a high-heeled shoe provided in an embodiment of the present invention.

[0026] Figure 3 This is a magnified view of a portion of the heel counter provided in an embodiment of the present invention.

[0027] Figure 4 The synthetic route for 4aPEG-PECH provided in the embodiments of the present invention.

[0028] Explanation of reference numerals in the attached figures: 1. Heel counter, 2. Heel opening, 3. Heel tip, 4. Heel sole, 5. Upper structure, 6. Angle α, 7. Angle β, 5-1 Base layer, 5-2. First adhesive layer, 5-3. Polyurethane microfoam layer, 5-4. Second adhesive layer, 5-5. Ankle contact layer. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. The embodiments described below are merely specific embodiments exemplified in this application to illustrate the technical solutions of this application, and are not intended to limit them. The scope of protection of this application is not limited thereto. In the description of the present invention, it should be noted that the terms "inner," "outer," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0030] This invention provides a multilayer composite material, see [link to related document]. Figure 1As shown, the structure includes a base layer 5-1, a first adhesive layer 5-2, a polyurethane microfoam layer 5-3, a second adhesive layer 5-4, and an ankle contact layer 5-5. The polyurethane microfoam layer 5-3 is made of polyurethane microfoam material, which serves to cushion, reduce friction, and cover the ankle. The density of the polyurethane microfoam material is 0.2-0.4 g / cm³. 3 The ASKER C hardness is 15-40; the first adhesive layer 5-2 and the second adhesive layer 5-4 are made of polyurethane adhesive; the base layer 5-1 is natural leather and / or artificial leather; and the ankle contact layer 5-5 is natural leather and / or artificial leather.

[0031] The present invention also provides the application of the above-mentioned multilayer composite material in high heels.

[0032] Specifically, the present invention also provides a shoe upper structure 5 for protecting ankle tendons, which adopts the above-mentioned multi-layer composite material and the shoe upper structure is arc-shaped.

[0033] The present invention also provides a high heel, see [link to relevant documentation]. Figure 2 and Figure 3 As shown, the heel counter 1 includes the aforementioned shoe upper structure 5 that protects the ankle tendons. The shoe upper structure 5 is positioned at the corresponding position that contacts the rear ankle. The shoe upper structure 5 extends upward to the heel opening 2 and downward to the heel end point 3 of the shoe upper. The height H between the heel end point 3 of the shoe upper and the horizontal line of the heel sole 4 is 17-35 mm. The angle α 6 between the arcuate tangent of the heel sole 4 at 2 / 3 of the height from the top of the heel opening 2 and the vertical line is 11-36 degrees, preferably 12-35 degrees. The angle β 7 between the arcuate tangent of the heel opening 2 and the horizontal plane is 58-76 degrees.

[0034] Example 1: Preparation of polyurethane microfoamed materials First, 10 parts by weight of commercially available four-armed polyethylene glycol (4aPEG) were completely dissolved in dichloromethane. Then, boron trifluoride catalyst diluted with 1,2-dichloroethane (4% by weight of 4aPEG) was added, with a catalyst concentration of 1 g / 1 mL of 1,2-dichloroethane, and mixed thoroughly. After thorough mixing, 40-450 parts by weight of epichlorohydrin were slowly added dropwise. The reaction was terminated after the reaction was complete. The reaction mixture was washed three times with saturated NaHCO3 solution, then washed with deionized water until neutral, and the organic phase was extracted. The extracted organic phase was dissolved in N,N-dimethylformamide (DMF), and the insoluble matter was removed by filtration. The filtrate was washed with a large amount of water to remove DMF, and the sedimentation yielded crude hydroxyl-terminated polyepoxychloropropane. The crude product was distilled under reduced pressure at 110 °C to obtain the final product, with a yield greater than 80%. The product was a pale yellow viscous liquid, namely hydroxyl-terminated polyepoxychloropropane. The synthetic route of hydroxyl-terminated polyepoxychloropropane (4aPEG-PECH) is as follows: Figure 4 As shown.

[0035] Mix 100 g of hydroxyl-terminated polyepoxychloropropane (PECH) with 30 g of castor oil, add 30 g of 5613 polyether polyol and 0.12 g of stannous octoate, mix well, then add 60 g of PAPI isocyanate, mix well, pour into a mold and cure at 60°C for 10 hours to obtain polyurethane microfoam material A.

[0036] Example 2: Preparation of polyurethane microfoamed materials Hydroxyl-terminated polyepoxychloropropane (PECH) was prepared as in Example 1.

[0037] Mix 100 g of hydroxyl-terminated polyepoxychloropropane (PECH) with 50 g of castor oil, add 40 g of 5613 polyether polyol and 0.15 g of stannous octoate, mix well, then add 70 g of PAPI isocyanate and mix well. Pour the mixture into a mold and cure at 80°C for 10 hours to obtain polyurethane microfoam material B.

[0038] Example 3: Preparation of polyurethane microfoamed materials Hydroxyl-terminated polyepoxychloropropane (PECH) was prepared as in Example 1.

[0039] Mix 100 g of hydroxyl-terminated polyepoxychloropropane (PECH) with 30 g of castor oil, add 20 g of 5613 polyether polyol and 0.10 g of stannous octoate, mix well, then add 50 g of PAPI isocyanate, mix well, inject the mixture into a mold and cure at 50°C for 20 hours to obtain polyurethane microfoam material C.

[0040] Comparative Example 1: Preparation of ordinary foamed materials Mix 100 g of polypropylene glycol with 20 g of castor oil, add 75 g of toluene diisocyanate, stir well, pour the mixture into a mold and cure at 60°C for 15 hours to obtain polyurethane material D.

[0041] Comparative Example 2: Preparation of Elastomer Materials Mix 100 g of polypropylene glycol with 20 g of castor oil, add 75 g of PAPI isocyanate, stir well, pour the mixture into a mold and cure at 60°C for 15 hours to obtain polyurethane material E.

[0042] The densities (g / cm³) of the above-mentioned polyurethane microfoam material AC and polyurethane material DE were tested. 3 The results of ASKER C hardness, strength (MPa), and elongation at break (%) are shown in Table 1.

[0043] Table 1. Performance test results of materials A–E

[0044] The results show that the polyurethane microfoam material AC successfully synthesized in this invention differs from polyurethane materials D and E in terms of density, ASKER C hardness, strength, and elongation at break. Specifically, the polyurethane microfoam material of this invention has a moderate density, is softer, and has higher strength than ordinary foam material D and polyurethane material E. Further optimizations have been made to meet the needs of high heels.

[0045] Example 4 Mix 100 g of hydroxyl-terminated polyepoxychloropropane (PECH) with 30 g of castor oil, add 30 g of 5613 polyether polyol and 0.12 g of stannous octoate, mix well, then add 60 g of PAPI isocyanate and mix well to obtain polyurethane precursor pre-A.

[0046] Using the inner layer of leather material as a substrate, polypropylene glycol is coated onto its surface and impregnated for 10 minutes. Polyurethane adhesive (prepolymer) is then applied to the treated leather surface and left to stand for 20 seconds. A polyurethane precursor (pre-A) is then evenly coated. A leather layer identical to the substrate is then attached, and the mixture is placed on a clamp and pressed. The clamp temperature is 60°C, and the temperature is maintained for 5 hours to obtain the composite material.

[0047] The material remained in its original leather form, without deformation or wrinkles, and no cracking was observed after rubbing it 1000 times at 40°C.

[0048] Example 5 Using the inner heel of the shoe upper as a substrate, polypropylene glycol is coated onto its surface and impregnated for 10 minutes. Polyurethane adhesive (prepolymer) is then applied to the treated leather surface and left to stand for 30 seconds. Polyurethane precursor pre-A is then evenly applied. A leather layer identical to the substrate is taken, coated with polypropylene glycol, and impregnated for 10 minutes. Polyurethane adhesive (prepolymer) is then applied to the inner surface of the treated leather. The leather layer with the polyurethane adhesive (prepolymer) attached is then placed over the polyurethane precursor pre-A layer and pressed firmly in a clamp at 50°C for 10 hours to obtain a shoe with the composite material.

[0049] The shoes retain their original leather surface, with no deformation or wrinkles, and no glue separation was observed when manually torn.

[0050] Example 6 The polyurethane microfoam material AC and polyurethane material DE prepared above are removed from the mold to form the desired crescent shape.

[0051] Using the inner heel of the shoe upper as a substrate, polypropylene glycol was coated onto its surface and impregnated for 10 minutes. Polyurethane adhesive (prepolymer) was then applied to the treated leather surface and left to stand for 30 seconds. Crescent-shaped polyurethane microfoam material AC and polyurethane material DE were placed on the adhesive-coated leather surface, and crescent-shaped material AE was tightly wrapped with adhesive-coated leather material (ankle contact layer). The adhesive was then cured to obtain a multi-layer composite material.

[0052] High heels are made directly from the aforementioned multi-layered composite material, with the positions of the multi-layered composite material corresponding to the ankle position.

[0053] The following tests were conducted on the shoe upper covering effect under different heel heights, angles α and β, heights H, types of composite materials, and thicknesses of composite materials. The test method involved providing sample shoes to testers for one hour of wear, and evaluating comfort and fatigue levels using a rating scale of 1-5, where 5 was comfortable and 1 was uncomfortable. The test results are shown in Table 2. The main reason for not using composite materials was discomfort caused by the shoe upper rubbing against the feet.

[0054] Table 2 Test Results of Upper Covering Effect 1 9.5 35-36 58-60 34-35 -- 0 2 2 9.5 35-36 58-60 34-35 Material A 1 4 3 9.5 35-36 58-60 34-35 Material B 3 4 4 9.5 35-36 58-60 34-35 Material C 1 4 5 9.5 35-36 58-60 34-35 Material D 3 2+ 6 9.5 35-36 58-60 34-35 Material E 3 2+ 7 9 26-28 63-66 29-31 -- 0 2 8 9 26-28 63-66 29-31 Material A 1 4 9 9 26-28 63-66 29-31 Material B 3 4 10 9 26-28 63-66 29-31 Material C 1 4 11 9 26-28 63-66 29-31 Material D 3 2+ 12 9 26-28 63-66 29-31 Material E 3 2+ 13 8.5 16-19 70-72 24-26 -- 0 3 14 8.5 16-19 70-72 24-26 Material A 1 4+ 15 8.5 16-19 70-72 24-26 Material B 3 4+ 16 8.5 16-19 70-72 24-26 Material C 1 4+ 17 8.5 16-19 70-72 24-26 Material D 3 3 18 8.5 16-19 70-72 24-26 Material E 3 3 19 8 11-14 74-76 17-19 -- 0 3 20 8 11-14 74-76 17-19 Material A 1 5 21 8 11-14 74-76 17-19 Material B 3 5 22 8 11-14 74-76 17-19 Material C 1 5 23 8 11-14 74-76 17-19 Material D 3 4 24 8 11-14 74-76 17-19 Material E 3 4 25 8 8-10 80-82 10-12 -- 0 2 26 8 42-43 45-48 42-45 -- 0 1 The results showed that, overall, higher heels resulted in a worse wearing experience. For the same heel height, as shown in Table 2 (tests 1-6), adding cushioning material reduced heel friction to some extent, thus improving comfort. However, adding cushioning material in tests 5 and 6 did not significantly improve comfort. The reason for this is that the cushioning material needs to consider multiple properties, not just simple friction prevention. Due to limitations in elasticity and strength, it could not provide effective support, resulting in insufficient shoe coverage and reduced comfort. Therefore, the overall wearing experience score was only 2+. Similar scores were found for heels of 9cm, and even as the heel height decreased, the difference in comfort with or without cushioning material became negligible.

[0055] Comparing Table 2, and comparing test numbers 1, 7, 13, and 19 with 25 and 26, it can be seen that shoe design has an impact on wearing comfort. Specifically, changes in the included angle α, included angle β, and height H affect wearing comfort. Only within the optimal range can a better wearing experience be obtained. It should be emphasized that included angle α, included angle β, and height H are the result of comprehensive adjustment; meeting the requirements of only one element will not achieve the desired effect.

[0056] Comparing Table 2, experiments 19-24 with 25 and 26 reveal that the choice of composite material at the foot and heel opening also affects wearing comfort, with different materials having significantly different impacts. Firstly, it needs to possess a certain level of cushioning to reduce friction; however, its hardness and elasticity cannot be too low. Low hardness and elasticity result in a poor fit between the shoe upper and the foot, causing the shoe to wobble and easily slip off, leading to discomfort and even injury. The polyurethane microfoam materials A, B, and C provided by this invention offer a better wearing experience due to their comprehensive properties such as foaming degree, hardness, and elasticity, surpassing ordinary polyurethane materials and even more so ordinary sponge materials.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] The embodiments described above are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in this application, or make equivalent substitutions for some of the specific technologies; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A multilayer composite material, characterized in that, It includes a base layer, a first adhesive layer, a polyurethane microfoam layer, a second adhesive layer, and an ankle contact layer, wherein the polyurethane microfoam layer is made of polyurethane microfoam material with a density of 0.26-0.36 g / cm³. 3 The ASKER C hardness is 20-36; the first and second adhesive layers are made of polyurethane adhesive; the base layer is natural leather and / or artificial leather; the ankle contact layer is natural leather and / or artificial leather; the polyurethane microfoam material is a polycondensation product of 100 parts by weight of hydroxyl-terminated polyepoxychloropropane and 50-70 parts by weight of PAPI isocyanate; the hydroxyl-terminated polyepoxychloropropane is a crosslinking ring-opening polymerization product of tetra-arm polyethylene glycol and epichlorohydrin under boron trifluoride catalysis; the structure of the hydroxyl-terminated polyepoxychloropropane is as shown in structural formula (I): （I） Wherein, a, b, m, n represent the number of repeating units in the polymer, and the number-average molecular weight of the terminal hydroxyl polyepoxychloropropane is 10500 Da.

2. The multilayer composite material according to claim 1, characterized in that, The viscosity of the terminal hydroxyl polyepoxychloropropane is 1.2 Pa•s.

3. The multilayer composite material according to claim 1, characterized in that, The preparation method of the polyurethane microfoam layer material includes: mixing 100 parts by weight of hydroxyl-terminated polyepoxychloropropane with 30-50 parts by weight of plasticizer, adding 20-40 parts by weight of 5613 polyether polyol and 0.1-0.15 parts by weight of stannous octoate and mixing evenly, adding 50-70 parts by weight of PAPI isocyanate and mixing evenly to obtain a precursor to be molded; adding the precursor to be molded into a mold and curing at a temperature of 50-80℃ for 10-20 hours to obtain the polyurethane microfoam material; the plasticizer is castor oil.

4. The molding method of the multilayer composite material according to any one of claims 1-3, characterized in that, Includes the following steps: Mix 100 parts by weight of hydroxyl-terminated polyepoxychloropropane with 30-50 parts by weight of plasticizer, add 20-40 parts by weight of 5613 polyether polyol and 0.1-0.15 parts by weight of stannous octoate and mix evenly, then add 50-70 parts by weight of PAPI isocyanate and mix evenly to obtain the precursor to be molded. A polyurethane adhesive is applied to the surface of the base layer and left for 30-180 seconds to form a first adhesive layer. The precursor to be molded is then applied to the surface of the first adhesive layer, and a polyurethane adhesive is applied to the surface of the precursor to be molded to form a second adhesive layer. An ankle contact layer is then covered on the surface of the second adhesive layer, and the mixture is placed in a mold and molded for 10-20 hours to obtain a multilayer composite material.

5. The application of the multilayer composite material according to any one of claims 1-3 in high heels.

6. A shoe upper structure for protecting ankle tendons, characterized in that, The shoe upper structure is arc-shaped and the thickness of the multilayer composite material is 1-3 mm.

7. A type of high heel, characterized in that, The heel counter includes the shoe upper structure for protecting the ankle tendons as described in claim 6. The shoe upper structure is positioned at a corresponding location that contacts the rear ankle. The shoe upper structure extends upward to the heel opening and downward to the heel end point of the shoe upper. The height H between the heel end point of the shoe upper and the horizontal line of the heel sole is 17-35 mm. The angle α between the arcuate tangent line of the heel sole at 2 / 3 of the height from the end of the heel opening and the vertical line is 11-36 degrees. The angle β between the arcuate tangent line of the heel opening and the horizontal plane is 58-76 degrees.

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