Special material for plant fiber insoles as well as preparation process and application of special material

Abstract

The invention relates to the field of insole materials, in particular to a material special for plant fiber insoles and a preparation technology and application thereof.The preparation technology comprises the following steps that 1, raw materials are mixed and fully stirred to be uniform, and a mixture A is obtained; (2) adding alkalized plant fibers weighed in parts by weight into the mixture A, and uniformly mixing to obtain a mixture B; and (3) cooling the mixture B, adding isocyanate weighed in parts by weight, uniformly mixing, injecting into a preheated mold, and carrying out foaming molding to obtain the special material for the plant fiber insole. Compared with the traditional composite material of plant fiber and polyurethane, the insole material prepared by the invention not only has better compression resistance, but also can maintain higher tensile strength and bending strength.

Description

Technical Field

[0001] The invention relates to the field of insole materials, and in particular to a special plant fiber insole material and a preparation process and application thereof. Background Art

[0002] The sole of a person's foot can be roughly divided into three parts: the forefoot, the foot pit and the heel. When a person is standing still or running at a constant speed, the stress on the sole of the foot is uneven and the pressure on the sole of the foot is inconsistent. Therefore, it is more important to improve the fit between the insole and the sole of the foot. The insoles of traditional sports shoes are usually made of foam materials with cushioning properties. The foam materials are mostly polyurethane or EVA foam materials. These materials have certain elasticity and cushioning properties, which play a role in cushioning the foot during exercise. However, the insoles made of these foam materials have poor durability and resilience, and do not have good strength and other properties, which affects the wearing effect.

[0003] Polyurethane materials are made by reacting polyols containing alcohol hydroxyl groups with isocyanates, and the commonly used polyols include polyether polyols and polyester polyols. The polyurethane materials made from traditional polyols have poor durable resilience and lack good strength and other properties, which makes the wearing experience poor. Plant fibers are light, cheap, easy to obtain, biodegradable, and environmentally friendly, and the crystallinity, orientation, and longitudinal elastic modulus of the fibers are high, making them very suitable for the reinforcing phase of resin-based composite materials. Therefore, the research and development of their composite materials has increasingly attracted people's attention. In the prior art, there are studies on adding plant fibers to polyurethane materials to improve the various properties of polyurethane materials. However, the compatibility of plant fibers with polyurethane materials is not ideal, and the performance improvement of polyurethane is very limited. Although the compressive properties of polyurethane foam can be enhanced to a certain extent, it is easy to cause a decrease in tensile strength and bending properties, thereby affecting the durable use of insole materials. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a special material for plant fiber insoles and its preparation process and application.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] In a first aspect, the present invention provides a process for preparing a plant fiber insole special material, comprising the following steps:

[0007] Step (1), mixing polyether diol, polyester diol, catalyst, chain extender, foaming agent and foam stabilizer, and stirring well to obtain mixture A;

[0008] Step (2), adding the alkalized plant fiber weighed in parts by weight into the mixture A, and mixing them evenly to obtain a mixture B;

[0009] Step (3), after cooling the mixed material B, adding isocyanate weighed in parts by weight, mixing evenly, injecting into a preheated mold, and foaming and molding to obtain a special material for plant fiber insoles.

[0010] Preferably, in step (1), the mixing temperature is 20-40° C., the mixing speed is 500-600 r / min, and the mixing time is 20-40 min.

[0011] Preferably, in step (2), the mixing temperature is 60-80° C., the mixing speed is 200-400 r / min, and the mixing time is 20-40 min.

[0012] Preferably, in step (3), the mixture B is cooled to 25-35° C., the mixing speed is 600-800 r / min, and the mixing time is 2-4 min.

[0013] Preferably, in step (3), the preheated mold temperature is 50-60° C., and the foaming molding time is 3-10 min.

[0014] Preferably, the plant fiber insole special material comprises the following components calculated by weight:

[0015] 32-48 parts of isocyanate, 53-76 parts of polyether diol, 20-40 parts of polyester diol, 8-16 parts of alkalized plant fiber, 0.6-1.2 parts of catalyst, 1.1-3.3 parts of chain extender, 1.2-2.4 parts of foaming agent and 0.6-1.2 parts of foam stabilizer.

[0016] Preferably, the isocyanate is a mixture of 4,4-diphenylmethane isocyanate (MDI) and carbodiimide-modified MDI (liquefied MDI), and the weight ratio of 4,4-diphenylmethane isocyanate to carbodiimide-modified MDI-100LL is 2-5:1.

[0017] Preferably, the polyether diol is polytetramethylene ether diol PTMEG-2000 (molecular weight 2000), and the polyester diol is polycarbonate diol PCDL-2000 (molecular weight 2000).

[0018] Preferably, the chain extender is prepared by a click chemistry reaction using 4,6-diamino-2-mercaptopyrimidine and N-vinylcaprolactam as raw materials.

[0019] Preferably, the catalyst is an environmentally friendly catalyst, including FOCAT-8002 or FOCAT-8003M; more preferably FOCAT-8002.

[0020] Preferably, the foaming agent is pure water.

[0021] Preferably, the foam stabilizer is high-resilience silicone oil, and the models include Maitu Y-10366 or Maitu L-5333; more preferably, Maitu Y-10366.

[0022] Preferably, the method for preparing the alkalized plant fiber comprises:

[0023] Sodium hydroxide powder, deionized water and ethanol are mixed, and stirred thoroughly until they are evenly dissolved to obtain a mixed solution of sodium hydroxide; plant fibers are weighed and added to the mixed solution of sodium hydroxide, and soaked at room temperature for 2-4 hours, and then the liquid is filtered out, and washed with pure water until the washing liquid is neutral, and then dried in a vacuum box to obtain activated plant fibers.

[0024] More preferably, the plant fiber is at least one of bamboo fiber, cotton fiber, wormwood fiber, coconut shell fiber, mint fiber, soybean fiber, corn fiber, flax fiber and sisal fiber.

[0025] More preferably, in the mixed solution of sodium hydroxide, the mass volume ratio of sodium hydroxide powder, deionized water and ethanol is (0.1-0.3) g: (12-24) mL: (6-12) mL.

[0026] More preferably, the mass volume ratio of the mixed solution of plant fiber and sodium hydroxide is 1 g:(10-30) mL.

[0027] Preferably, the preparation method of the chain extender comprises:

[0028] S1. Weigh 4,6-diamino-2-mercaptopyrimidine and N-vinyl caprolactam and add them into anhydrous ethanol, stir and mix thoroughly to obtain a mixed solution A;

[0029] S2. Under the protection of nitrogen, add a photoinitiator to the mixed solution A, and stir the reaction for 0.8-2.4 hours under the irradiation of ultraviolet light. After the reaction is completed, remove the solvent by rotary evaporation to obtain a chain extender.

[0030] Preferably, in S1, the mass volume ratio of 4,6-diamino-2-mercaptopyrimidine, N-vinylcaprolactam and anhydrous ethanol is (1.4-2.8) g: (1.5-3) g: (30-50) mL.

[0031] Preferably, in S2, the photoinitiator is benzoin methyl ether or benzoin dimethyl ether, and the added mass of the photoinitiator is 3.2%-6.4% of the mass of 4,6-diamino-2-mercaptopyrimidine.

[0032] Preferably, in S2, the wavelength of the ultraviolet light is 300-400nm, and the light intensity is 150-250mw / cm 2 , the stirring speed is 100-200r / min.

[0033] In a second aspect, the present invention provides a special material for plant fiber insoles, which is prepared by the above-mentioned preparation method.

[0034] In a third aspect, the present invention provides an application of a plant fiber insole material in sports shoes or casual shoes.

[0035] The beneficial effects of the present invention are:

[0036] 1. The present invention prepares a special material for insoles, which is a polyurethane material with plant fibers added. In order to enhance the performance of the material, the present invention improves the material, including using mixed isocyanate and diol as the main raw materials, activating the plant fibers, and using a homemade chain extender. Compared with traditional composite materials of plant fibers and polyurethane, the insole material prepared by the present invention not only has better compressive performance, but also can maintain higher tensile strength and bending strength.

[0037] 2. The main raw materials of the special insole material prepared by the present invention adopt a blend of MDI and liquefied MDI as isocyanate, a blend of PTMEG and PCDL as diol, the plant fiber is an alkalized plant fiber, and the chain extender is prepared by a thiol-olefin click chemistry reaction using 4,6-diamino-2-mercaptopyrimidine and N-vinylcaprolactam as raw materials.

[0038] 3. The present invention treats the plant fiber in an alkali solution at room temperature, thus avoiding a substantial drop in the strength of the fiber material due to temperature rise. The hydroxyl activity on the surface of the plant fiber is greatly enhanced after alkali treatment, and the design of the present invention is to use the alkali-treated plant fiber as a synthetic raw material, first fully mix it with an alcohol material, and then react with isocyanate, so that the polyurethane can be closely cross-linked with the plant fiber during the synthesis process, which can enhance the performance of the polyurethane material to a certain extent.

[0039] 4. The chain extender used in the present invention contains a caprolactam group and a thioether group, which greatly improves the stability and strength of the prepared polyurethane material, thereby enabling the polyurethane material to maintain good mechanical properties. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0041] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0042] The present invention will be further described below in conjunction with the following examples.

[0043] Example 1

[0044] A plant fiber insole special material, calculated by weight, includes the following components:

[0045] 40 parts of isocyanate, 64 parts of polyether diol, 30 parts of polyester diol, 12 parts of alkalized plant fiber, 0.9 parts of catalyst, 2.2 parts of chain extender, 1.8 parts of foaming agent and 0.9 parts of foam stabilizer.

[0046] Among them, the isocyanate is a mixture of 4,4-diphenylmethane isocyanate (MDI) and carbodiimide-modified MDI (liquefied MDI), and the weight ratio of 4,4-diphenylmethane isocyanate to carbodiimide-modified MDI-100LL is 3:1; the polyether diol is polytetramethylene ether diol PTMEG-2000, and the polyester diol is polycarbonate diol PCDL-2000.

[0047] Among them, the catalyst is the environmentally friendly catalyst FOCAT-8002; the foaming agent is pure water; and the foam stabilizer is the high-resilience silicone oil Maitu Y-10366.

[0048] The preparation method of alkalized plant fiber comprises:

[0049] Sodium hydroxide powder, deionized water and ethanol were mixed in a mass volume ratio of 0.2 g:18 mL:8 mL, and the mixture was stirred until uniformly dissolved to obtain a mixed solution of sodium hydroxide. Coconut shell fiber (diameter 100 μm, length 5 mm, density 1.15 g / cm 3 ) is added to a mixed solution of sodium hydroxide, the mass volume ratio of the mixed solution of coconut shell fiber and sodium hydroxide is 1g:20mL, soaked at room temperature for 3h, then filtered to remove the liquid, washed with pure water until the washing liquid is neutral, and then placed in a vacuum box to dry to obtain activated plant fiber.

[0050] Wherein, the preparation method of the chain extender comprises:

[0051] S1. Weigh 4,6-diamino-2-mercaptopyrimidine and N-vinyl caprolactam and add them to anhydrous ethanol. The mass volume ratio of 4,6-diamino-2-mercaptopyrimidine, N-vinyl caprolactam and anhydrous ethanol is 2.1 g: 2.3 g: 40 mL. Stir and mix well to obtain a mixed solution A.

[0052] S2. Under the protection of nitrogen, add the photoinitiator benzoin dimethyl ether to the mixed solution A, the added mass is 4.6% of the mass of 4,6-diamino-2-mercaptopyrimidine, and stir the reaction for 1.5 hours under the irradiation of ultraviolet light. The wavelength of ultraviolet light is 365nm and the light intensity is 200mw / cm 2 The stirring speed is 150r / min. After the reaction is completed, the solvent is removed by rotary evaporation to obtain a chain extender.

[0053] The preparation process of the above-mentioned plant fiber insole special material comprises the following steps:

[0054] Step (1), mixing polyether diol, polyester diol, catalyst, chain extender, foaming agent and foam stabilizer, stirring at 30° C. and 550 r / min for 30 min to obtain a mixture A;

[0055] Step (2), adding the alkalized plant fiber weighed in parts by weight into the mixture A, stirring at 70° C. and 300 r / min for 30 min to obtain a mixture B;

[0056] Step (3), after cooling the mixed material B to 30°C, adding isocyanate weighed according to the weight, stirring at a speed of 700 r / min for 3 minutes, injecting into a mold preheated to 55°C, and foaming for 8 minutes to obtain a special material for plant fiber insoles.

[0057] Example 2

[0058] A plant fiber insole special material, calculated by weight, includes the following components:

[0059] 32 parts of isocyanate, 53 parts of polyether diol, 20 parts of polyester diol, 8 parts of alkalized plant fiber, 0.6 parts of catalyst, 1.1 parts of chain extender, 1.2 parts of foaming agent and 0.6 parts of foam stabilizer.

[0060] Among them, the isocyanate is a mixture of 4,4-diphenylmethane isocyanate (MDI) and carbodiimide-modified MDI (liquefied MDI), and the weight ratio of 4,4-diphenylmethane isocyanate to carbodiimide-modified MDI-100LL is 2:1; the polyether diol is polytetramethylene ether diol PTMEG-2000, and the polyester diol is polycarbonate diol PCDL-2000.

[0061] Among them, the catalyst is the environmentally friendly catalyst FOCAT-8003M; the foaming agent is pure water; and the foam stabilizer is the high-resilience silicone oil Maitu L-5333.

[0062] The preparation method of alkalized plant fiber comprises:

[0063] Sodium hydroxide powder, deionized water and ethanol are mixed in a mass volume ratio of 0.1 g:12 mL:6 mL, and the mixture is stirred fully until uniformly dissolved to obtain a mixed solution of sodium hydroxide; bamboo fiber is weighed and added to the mixed solution of sodium hydroxide in a mass volume ratio of 1 g:10 mL, and the mixture is soaked at room temperature for 2 h, and then the liquid is filtered out, and the mixture is washed with pure water until the washing liquid is neutral, and then dried in a vacuum box to obtain activated plant fiber.

[0064] Wherein, the preparation method of the chain extender comprises:

[0065] S1. Weigh 4,6-diamino-2-mercaptopyrimidine and N-vinyl caprolactam and add them to anhydrous ethanol. The mass volume ratio of 4,6-diamino-2-mercaptopyrimidine, N-vinyl caprolactam and anhydrous ethanol is 1.4 g: 1.5 g: 30 mL. Stir and mix well to obtain a mixed solution A.

[0066] S2. Under the protection of nitrogen, add the photoinitiator benzoin methyl ether to the mixed solution A, the added mass is 3.2% of the mass of 4,6-diamino-2-mercaptopyrimidine, and stir the reaction for 0.8h under the irradiation of ultraviolet light. The wavelength of ultraviolet light is 365nm and the light intensity is 150mw / cm 2 The stirring speed is 100r / min. After the reaction is completed, the solvent is removed by rotary evaporation to obtain a chain extender.

[0067] The preparation process of the above-mentioned plant fiber insole special material comprises the following steps:

[0068] Step (1), mixing polyether diol, polyester diol, catalyst, chain extender, foaming agent and foam stabilizer, stirring at 20° C. and 500 r / min for 20 min to obtain a mixture A;

[0069] Step (2), adding the alkalized plant fiber weighed in parts by weight into the mixture A, stirring at 200 r / min at 60° C. for 20 min, to obtain a mixture B;

[0070] Step (3), after cooling the mixed material B to 25°C, adding isocyanate weighed according to the weight, stirring at a speed of 600r / min for 2min, injecting into a mold preheated to 50°C, and foaming for 3min to obtain the special material for plant fiber insoles.

[0071] Example 3

[0072] A plant fiber insole special material, calculated by weight, includes the following components:

[0073] 48 parts of isocyanate, 76 parts of polyether diol, 40 parts of polyester diol, 16 parts of alkalized plant fiber, 1.2 parts of catalyst, 3.3 parts of chain extender, 2.4 parts of foaming agent and 1.2 parts of foam stabilizer.

[0074] Among them, the isocyanate is a mixture of 4,4-diphenylmethane isocyanate (MDI) and carbodiimide modified MDI (liquefied MDI), and the weight ratio of 4,4-diphenylmethane isocyanate to carbodiimide modified MDI-100LL is 5:1; the polyether diol is polytetramethylene ether diol PTMEG-2000, and the polyester diol is polycarbonate diol PCDL-2000.

[0075] Among them, the catalyst is the environmentally friendly catalyst FOCAT-8002; the foaming agent is pure water; and the foam stabilizer is the high-resilience silicone oil Maitu Y-10366.

[0076] The preparation method of alkalized plant fiber comprises:

[0077] Sodium hydroxide powder, deionized water and ethanol are mixed in a mass volume ratio of 0.1 g:12 mL:6 mL, and the mixture is stirred fully until uniformly dissolved to obtain a mixed solution of sodium hydroxide; soybean fiber is weighed and added to the mixed solution of sodium hydroxide in a mass volume ratio of 1 g:10 mL, and the mixture is soaked at room temperature for 2 h, and then the liquid is filtered out, and the mixture is washed with pure water until the washing liquid is neutral, and then dried in a vacuum box to obtain activated plant fiber.

[0078] Wherein, the preparation method of the chain extender comprises:

[0079] S1. Weigh 4,6-diamino-2-mercaptopyrimidine and N-vinyl caprolactam and add them to anhydrous ethanol. The mass volume ratio of 4,6-diamino-2-mercaptopyrimidine, N-vinyl caprolactam and anhydrous ethanol is 2.8g:3g:50mL. Stir and mix well to obtain a mixed solution A;

[0080] S2. Under the protection of nitrogen, add the photoinitiator benzoin dimethyl ether to the mixed solution A, the added mass is 6.4% of the mass of 4,6-diamino-2-mercaptopyrimidine, and stir the reaction for 2.4 hours under the irradiation of ultraviolet light. The wavelength of ultraviolet light is 365nm and the light intensity is 250mw / cm 2 The stirring speed is 200r / min. After the reaction is completed, the solvent is removed by rotary evaporation to obtain a chain extender.

[0081] The preparation process of the above-mentioned plant fiber insole special material comprises the following steps:

[0082] Step (1), mixing polyether diol, polyester diol, catalyst, chain extender, foaming agent and foam stabilizer, stirring at 40° C. and 600 r / min for 40 min to obtain a mixture A;

[0083] Step (2), adding the alkalized plant fiber weighed in parts by weight into the mixture A, stirring at 80° C. at a speed of 400 r / min for 40 minutes to obtain a mixture B;

[0084] Step (3), after cooling the mixture B to 35°C, adding isocyanate weighed according to the weight, stirring at a speed of 800r / min for 4 minutes, injecting into a mold preheated to 60°C, and foaming for 10 minutes to obtain a special material for plant fiber insoles.

[0085] Comparative Example 1

[0086] A special material for plant fiber insoles, which differs from Example 1 in that the chain extender in the composition is replaced by the traditional chain extender diethyltoluenediamine (DETDA), and other components and preparation methods remain unchanged.

[0087] Comparative Example 2

[0088] A special material for plant fiber insoles, which differs from Example 1 in that the alkalized plant fiber in the ingredients is replaced by unmodified plant fiber, the chain extender is replaced by the traditional chain extender diethyltoluenediamine (DETDA), and the other ingredients and preparation method remain unchanged.

[0089] Comparative Example 3

[0090] A special material for plant fiber insoles, which differs from Example 1 in that the chain extender in the composition is replaced by 4,6-diamino-2-mercaptopyrimidine, and other components and preparation methods remain unchanged.

[0091] Experimental testing

[0092] In order to more clearly illustrate the content of the present invention, the present invention tests and compares the properties of the plant fiber insole special material prepared in Example 1 and Comparative Examples 1-3, and the test results are listed in Table 1. Among them, the tensile strength test refers to the method of GB / T 528-2009; the tear strength test refers to the method of GB / T 529-2008; the air permeability test uses a polymer porous elastic material air permeability tester to test the air permeability, the test pressure is 0.2MPa, and the test time is 24h; the compression permanent set rate test refers to the method of ISO 1856-2007.

[0093] The results are shown in Table 1:

[0094] Table 1 Performance test results of different insole materials

[0095] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tensile strength(kPa) 1541 1126 917 1285 Tear strength (kN / m) 3.9 2.5 2.1 2.8 <![CDATA[Air permeability (mL / m 2 )]]> 623 585 573 604 Compression set rate (%) 11.2 13.4 13.9 12.0

[0096] It can be seen from Table 1 that the plant fiber insole material prepared in Example 1 can have significantly higher tensile strength and tear strength while maintaining good air permeability and compression resistance compared with Comparative Examples 1-3, indicating that the insole material prepared in Example 1 of the present invention has better comprehensive performance.

[0097] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0098] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A preparation process of a special material for plant fiber insoles, characterized in that: The following steps are involved: Step (1), mixing polyether diol, polyester diol, catalyst, chain extender, foaming agent and foam stabilizer, and stirring well to obtain mixture A; Step (2), adding the alkalized plant fiber to the mixture A, mixing evenly, to obtain a mixture B; Step (3), after cooling the mixed material B, adding isocyanate, mixing evenly, injecting into a preheated mold, and performing foaming molding to obtain a special material for plant fiber insoles; The plant fiber insole special material comprises the following components calculated by weight: 32-48 parts of isocyanate, 53-76 parts of polyether diol, 20-40 parts of polyester diol, 8-16 parts of alkalized plant fiber, 0.6-1.2 parts of catalyst, 1.1-3.3 parts of chain extender, 1.2-2.4 parts of foaming agent and 0.6-1.2 parts of foam stabilizer; The chain extender is prepared by using 4,6-diamino-2-mercaptopyrimidine and N-vinylcaprolactam as raw materials through a click chemistry reaction.

2. The preparation process of a plant fiber insole special material according to claim 1, characterized in that: In the step (1), the mixing temperature is 20-40°C, the mixing speed is 500-600 r / min, and the mixing time is 20-40 min; in the step (2), the mixing temperature is 60-80°C, the mixing speed is 200-400 r / min, and the mixing time is 20-40 min; in the step (3), the mixture B is cooled to 25-35°C, the mixing speed is 600-800 r / min, and the mixing time is 2-4 min; the preheated mold temperature is 50-60°C, and the foaming molding time is 3-10 min.

3. The preparation process of a plant fiber insole special material according to claim 1, characterized in that: The isocyanate is a mixture of 4,4-diphenylmethane isocyanate and carbodiimide-modified MDI, and the weight ratio of 4,4-diphenylmethane isocyanate to carbodiimide-modified MDI is 2-5:

1.

4. The preparation process of a plant fiber insole special material according to claim 1, characterized in that: The polyether diol is polytetramethylene ether diol PTMEG-2000, and the polyester diol is polycarbonate diol PCDL-2000.

5. The preparation process of a plant fiber insole special material according to claim 1, characterized in that: The catalyst is an environmentally friendly catalyst, including FOCAT-8002 or FOCAT-8003M.

6. The preparation process of a plant fiber insole special material according to claim 1, characterized in that: The foaming agent is pure water; the foam stabilizing agent is high-resilience silicone oil, and the models include Maitu Y-10366 or Maitu L-5333.

7. The preparation process of a plant fiber insole special material according to claim 1, characterized in that: The preparation method of the alkalized plant fiber comprises: Sodium hydroxide powder, deionized water and ethanol are mixed, and stirred thoroughly until they are uniformly dissolved to obtain a mixed solution of sodium hydroxide; plant fibers are weighed and added to the mixed solution of sodium hydroxide, and soaked at room temperature for 2-4 hours, and then the liquid is removed by filtering, and the fibers are washed with pure water until the washing liquid is neutral, and then dried in a vacuum box to obtain activated plant fibers; wherein the mass volume ratio of the sodium hydroxide powder, deionized water and ethanol is (0.1-0.3) g:(12-24) mL:(6-12) mL; and the mass volume ratio of the mixed solution of plant fibers and sodium hydroxide is 1 g:(10-30) mL.

8. The preparation process of a special material for plant fiber insoles according to claim 1, characterized in that: The preparation method of the chain extender comprises: S1. Weigh 4,6-diamino-2-mercaptopyrimidine and N-vinyl caprolactam and add them to anhydrous ethanol, stir and mix them evenly to obtain a mixed solution A; wherein the mass volume ratio of 4,6-diamino-2-mercaptopyrimidine, N-vinyl caprolactam and anhydrous ethanol is (1.4-2.8) g:(1.5-3) g:(30-50) mL; S2. Under the protection of nitrogen, add a photoinitiator to the mixed solution A, and stir the reaction for 0.8-2.4 hours under the irradiation of ultraviolet light. After the reaction is completed, remove the solvent by rotary evaporation to obtain a chain extender.

9. A plant fiber insole special material, characterized in that: The special material is prepared by the preparation process described in claim 1.

10. Use of the plant fiber insole material according to claim 9 in sports shoes or casual shoes.