Bio-based environment-friendly breathable insole and production process thereof

Abstract

The invention relates to a bio-based environment-friendly breathable insole and a production process thereof, and belongs to the technical field of polymer foaming materials. The insole is formed by foaming a polyurethane foaming material, and is prepared from the following components in parts by weight: 100 parts of polyurethane prepolymer, 9 to 14 parts of reinforced bio-based filler, 0.2 to 0.3 part of catalyst, 0.4 to 0.5 part of foam stabilizer, 0.7 to 0.9 part of pore opening agent, 1.1 to 1.3 parts of cross-linking agent and 6.5 to 8.5 parts of water, the reinforced bio-based filler is kept stable at the initial water system foaming temperature, formation of complete foam holes is facilitated, the reinforced bio-based filler is dispersed in hole walls, in the subsequent high-temperature foaming environment, an oxazolidine structure on the surface of the reinforced bio-based filler is hydrolyzed to generate active groups, and the active groups are cross-linked with the polyurethane prepolymer again, so that the foaming performance of the reinforced bio-based filler is improved. The bonding strength of the lignin fiber and a polyurethane macromolecular chain is enhanced, and the foam hole wall is enhanced, so that the foam hole structure is stable, and the mechanical strength and the rebound rate of the material are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer foaming materials, and in particular relates to a bio-based environmentally friendly breathable insole and a production process thereof. Background Art

[0002] Existing insoles are mainly made of EVA, silicone and other materials. Although these materials have the advantages of being light and soft, their air permeability, moisture permeability and shock absorption performance are insufficient. Although EVA insoles are light and comfortable, long-term wearing can easily cause the feet to become stuffy and humid, and their elasticity is limited, making it difficult to effectively reduce shock. Silicone insoles have better moisture permeability and stronger shock absorption performance, but they lack lightness and good air circulation, and are also prone to accumulating bacteria and breeding odors. Therefore, the development of new insole materials with excellent air permeability, moisture permeability, comfort and shock absorption performance is still a difficult problem facing the insole industry.

[0003] Polyurethane foam material has significant advantages due to its unique microporous structure and physical properties. It is filled with a large number of independent tiny bubbles, which can effectively promote airflow and enhance air permeability and moisture permeability. At the same time, polyurethane has good elasticity and resilience, can effectively absorb impact and provide excellent shock absorption performance. In addition, its hardness and density can be adjusted according to different needs to meet the diverse insole design needs.

[0004] However, polyurethane foam insoles have the defect of insufficient mechanical strength, and are difficult to withstand the extrusion and stretching caused by long-term wear or heavy pressure, which causes the insoles to be easily deformed, thinned, or even deformed and damaged, affecting their service life and comfort. Existing methods for optimizing polyurethane foam insoles usually focus on improving material formulas or manufacturing processes. For example, fillers such as reinforcing fibers are added to the material formula for reinforcement, but the bonding strength between these fillers and polyurethane is not high, and the fillers, as external dopants, are prone to deformation of the insoles, and the performance improvement of the insoles is limited; there are also cross-linked materials compounded into the raw materials to increase the strength by increasing the cross-linking degree of polyurethane, such as polyamines and polyols. These materials cross-link with polyurethane prematurely during the foaming process to form bubbles, which affects the comfort of the insoles. Summary of the invention

[0005] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a bio-based environmentally friendly breathable insole and a production process thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A bio-based environmentally friendly breathable insole is formed by foaming a polyurethane foam material, and comprises, by weight: 100 parts of polyurethane prepolymer, 9-14 parts of reinforced bio-based filler, 0.2-0.3 parts of catalyst, 0.4-0.5 parts of foam stabilizer, 0.7-0.9 parts of cell opener, 1.1-1.3 parts of crosslinking agent and 6.5-8.5 parts of water.

[0007] The reinforced bio-based filler is prepared by the following method: Step A1: diethanolamine and dioxane are mixed, nitrogen is introduced for protection, the temperature is raised to 40-50°C, stirring is applied at 60-90 rpm, formaldehyde is slowly added for reaction for 1.5-2h, then p-toluenesulfonic acid is added and mixed, the temperature is raised to 100-105°C, refluxed to separate water, the reaction is carried out for 2.2-2.8h, and dioxane is removed by rotary evaporation to obtain an intermediate; Furthermore, the usage ratio of diethanolamine, formaldehyde, p-toluenesulfonic acid and dioxane is 0.1 mol: 0.12-0.14 mol: 0.1-0.15 g: 35-45 mL, and diethanolamine and formaldehyde undergo a Mannheim reaction to form a hydroxyl-containing oxazolidine compound.

[0008] Step A2: The intermediate and dichloroethane are mixed, dry nitrogen is introduced for protection, the temperature is controlled at 5-15°C in an ice-water bath, stirring is applied at 150-180 rpm, vinyltrichlorosilane is slowly added to react for 2-3 hours, sodium hydroxide is added and mixed, the temperature is raised to 65-75°C and the reaction is continued for 1-1.5 hours. After the reaction is completed, the dichloroethane is removed by filtration and rotary evaporation to obtain a modifier; Furthermore, the usage ratio of the intermediate, vinyltrichlorosilane, sodium hydroxide and dichloroethane is 0.1 mol: 0.35-0.4 mol: 1.2-1.6 g: 60-70 mL, and the active chlorosilane group of vinyltrichlorosilane is substituted and etherified with the hydroxyl group of the intermediate to form an alkenyl-containing branched oxazolidine compound.

[0009] Step A3: Mix the silane coupling agent KH-580 and the ethanol solution, adjust the pH value to 3-4, stir and hydrolyze for 0.6-0.8h, add the lignin fiber and mix and beat for 2.5-3h, stand and age for 24h after neutralization, remove the supernatant and dry to obtain coupled fiber; Furthermore, the dosage ratio of lignin fiber, silane coupling agent KH-580 and ethanol solution is 50g:2.4-3.2g:55-70mL, and the silane coupling agent KH-580 is hydrolyzed and coupled with the lignin fiber to introduce active thiol groups to the surface of the lignin fiber.

[0010] Step A4: premix the modifier, photoinitiator, ethyl acetate and acetone, add the coupled fiber and mix, heat to 50-60°C, stir at 90-120 rpm and 150-200 W / m 2 UV irradiation, reaction for 3.5-4.5 hours, filter pressing and drying after the reaction to obtain a reinforced bio-based filler; Furthermore, the usage ratio of the coupling fiber, the modifier, the photoinitiator, the ethyl acetate and the acetone is 50 g: 3.8-4.4 g: 0.2-0.3 g: 25-40 mL: 55-70 mL. Under the initiation of ultraviolet light, the olefinic group in the modifier molecule click-adds with the thiol group introduced on the surface of the coupling fiber, thereby grafting the modifier molecule to the surface of the coupling fiber.

[0011] A production process of a bio-based environmentally friendly breathable insole, comprising the following steps: Step S1: premixing a reinforced bio-based filler, a catalyst, a foam stabilizer, a cell opening agent, a crosslinking agent and water, and then adding a polyurethane prepolymer and mixing well to obtain a polyurethane foam material; Step S2: inject the foaming material into the mold, foam it at 60-80° C. for 50-65 minutes, then continue to heat it to 110-120° C. for further foaming for 25-35 minutes, demold and dry it to obtain a bio-based environmentally friendly breathable insole.

[0012] Preferably, the catalyst is selected from dibutyltin dilaurate.

[0013] Preferably, the crosslinking agent is selected from D230 polyetheramine.

[0014] Beneficial effects of the present invention: The invention discloses a foamed polyurethane insole material, which introduces a reinforced bio-based filler with lignin fiber as a carrier to improve the mechanical strength of the insole material, and at the same time, applies natural lignin fiber in the product to give the insole a certain biological environmental protection property; the reinforced bio-based filler is formed by a Mann reaction of diethanolamine and formaldehyde to form a hydroxyl-containing oxazolidine compound, i.e., an intermediate, and then the active chlorosilane group of vinyl trichlorosilane and the hydroxyl group of the intermediate are substituted and etherified to form an alkenyl-containing branched oxazolidine compound, i.e., a modifier, which is hydrolyzed by a silane coupling agent KH-580 and coupled with lignin fiber, and active thiol groups are introduced into the surface of the lignin fiber to obtain coupled fiber, and the alkenyl groups in the modifier molecules are substituted and etherified with the coupling group under ultraviolet light initiation. The thiol click addition introduced on the fiber surface grafts the modifier molecules onto the coupled fiber surface, introduces a multi-branched oxazolidine structure modification, and cooperates with the two-stage foaming process. At the initial water system foaming temperature, the oxazolidine structure remains stable, which is conducive to the formation of complete bubbles, and the reinforced bio-based filler is dispersed in the pore wall. Under the action of tension, the fibrous reinforced bio-based filler is interwoven along the pore wall. In the subsequent high-temperature foaming environment, the oxazolidine structure on the surface of the reinforced bio-based filler is hydrolyzed to produce active groups, which are cross-linked with the polyurethane prepolymer again, strengthening the bonding strength between the lignin fiber and the polyurethane macromolecular chain, strengthening the pore wall, and stabilizing the pore structure, thereby significantly improving the mechanical strength and resilience of the material. DETAILED DESCRIPTION

[0015] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] Example 1, preparation of bio-based environmentally friendly breathable insoles, the specific implementation process is as follows: (1) Preparation of enhanced bio-based fillers Step A1: Take diethanolamine and dioxane and mix them, introduce nitrogen protection, heat to 50°C, apply stirring at 90rpm, slowly add formaldehyde to react for 1.5h, then add p-toluenesulfonic acid to mix, heat to 105°C, reflux to separate water, react for 2.2h, and remove dioxane by rotary evaporation to obtain an intermediate, wherein formaldehyde is added in the formaldehyde solution with a mass fraction of 40%, and the dosage ratio of diethanolamine, formaldehyde, p-toluenesulfonic acid and dioxane is 0.1mol:0.14mol:0.15g:45mL.

[0017] Step A2: Take the intermediate and dichloroethane and mix them, pass dry nitrogen for protection, control the temperature at 15°C in an ice-water bath, apply stirring at 180rpm, slowly add vinyltrichlorosilane to react for 2h, then add sodium hydroxide and mix, raise the temperature to 75°C and continue to react for 1h. After the reaction is completed, filter and remove dichloroethane by rotary evaporation to obtain a modifier, wherein the amount ratio of the intermediate, vinyltrichlorosilane, sodium hydroxide and dichloroethane is 0.1mol:0.4mol:1.6g:70mL.

[0018] Step A3: Mix the silane coupling agent KH-580 and the ethanol solution, adjust the pH value to 3 with formic acid, stir and hydrolyze for 0.6h, add the lignin fiber and mix and beat for 2.5h, neutralize with ammonia water and let stand for 24h, remove the supernatant and dry to obtain coupled fibers, wherein the volume concentration of the ethanol solution is 40% aqueous solution, the lignin fiber is commercially available with an average fiber length of 3mm, and the amount ratio of lignin fiber, silane coupling agent KH-580 and ethanol solution is 50g:3.2g:70mL.

[0019] Step A4: Take the premix of modifier, photoinitiator, ethyl acetate and acetone, add the coupled fiber and mix, heat to 60°C, apply 120 rpm stirring and 200 W / m 2 The mixture was irradiated with ultraviolet light and reacted for 3.5 hours. After the reaction, the mixture was filtered and dried to obtain a reinforced bio-based filler, wherein the amount ratio of the coupling fiber, the modifier, the photoinitiator, the ethyl acetate and the acetone was 50 g: 4.4 g: 0.3 g: 40 mL: 55 mL.

[0020] (2) Preparation of bio-based environmentally friendly breathable insoles Ingredients: The raw materials are calculated according to weight: 100 parts of polyurethane prepolymer, and H2128A prepolymer raw material is used in the implementation process; 9 parts of reinforced bio-based filler, which is homemade in this embodiment; 0.2 parts of catalyst, and dibutyltin dilaurate is used in the implementation process; 0.4 parts of foam stabilizer, and L-580 silicone oil is used in the implementation process; 0.9 parts of pore opener, and K340 soft foam pore opener is used in the implementation process; 1.3 parts of cross-linking agent, and D230 polyetheramine is used in the implementation process; 6.5 parts of water.

[0021] Step S1: Add the reinforced bio-based filler, catalyst, foam stabilizer, pore opening agent, cross-linking agent and water into a mixer and premix at 600 rpm for 5 minutes, then add the polyurethane prepolymer and continue mixing for 3 minutes to obtain a polyurethane foam material.

[0022] Step S2: inject the foaming material into the mold, foam it at 80° C. for 50 minutes, then continue to heat it to 120° C. for further foaming for 25 minutes, demold and dry it to obtain a bio-based environmentally friendly breathable insole.

[0023] Example 2, preparing a bio-based environmentally friendly breathable insole, the specific implementation process is as follows: (1) Preparation of enhanced bio-based fillers Step A1: Mix diethanolamine and dioxane, introduce nitrogen protection, heat to 40°C, stir at 60rpm, slowly add formaldehyde to react for 2h, then add p-toluenesulfonic acid to mix, heat to 100°C, reflux to separate water, react for 2.8h, and remove dioxane by rotary evaporation to obtain an intermediate, wherein formaldehyde is added in the formaldehyde solution with a mass fraction of 40%, and the dosage ratio of diethanolamine, formaldehyde, p-toluenesulfonic acid and dioxane is 0.1mol:0.12mol:0.1g:35mL.

[0024] Step A2: Take the intermediate and dichloroethane and mix them, pass dry nitrogen for protection, control the temperature at 5°C in an ice-water bath, apply stirring at 150rpm, slowly add vinyltrichlorosilane to react for 3h, then add sodium hydroxide and mix, raise the temperature to 65°C and continue to react for 1.5h. After the reaction is completed, filter and remove dichloroethane by rotary evaporation to obtain a modifier, wherein the amount ratio of the intermediate, vinyltrichlorosilane, sodium hydroxide and dichloroethane is 0.1mol:0.35mol:1.2g:60mL.

[0025] Step A3: Mix the silane coupling agent KH-580 and the ethanol solution, adjust the pH value to 4 with formic acid, stir and hydrolyze for 0.8h, add the lignin fiber and mix and beat for 3h, neutralize with ammonia water and let stand for 24h, remove the supernatant and dry to obtain coupled fibers, wherein the volume concentration of the ethanol solution is 40% aqueous solution, the lignin fiber is commercially available with an average fiber length of 3mm, and the amount ratio of lignin fiber, silane coupling agent KH-580 and ethanol solution is 50g:2.4g:55mL.

[0026] Step A4: Take the premix of modifier, photoinitiator, ethyl acetate and acetone, add the coupled fiber and mix, heat to 50°C, stir at 90 rpm and 150 W / m 2 The mixture was irradiated with ultraviolet light and reacted for 4.5 hours. After the reaction, the mixture was filtered and dried to obtain a reinforced bio-based filler, wherein the amount ratio of the coupling fiber, the modifier, the photoinitiator, the ethyl acetate and the acetone was 50 g: 3.8 g: 0.2 g: 25 mL: 70 mL.

[0027] (2) Preparation of bio-based environmentally friendly breathable insoles Ingredients: The raw materials are calculated according to weight: 100 parts of polyurethane prepolymer, and H2128A prepolymer raw material is used in the implementation process; 14 parts of reinforced bio-based filler, which is homemade in this embodiment; 0.3 parts of catalyst, and dibutyltin dilaurate is used in the implementation process; 0.5 parts of foam stabilizer, and L-580 silicone oil is used in the implementation process; 0.7 parts of pore opener, and K340 soft foam pore opener is used in the implementation process; 1.1 parts of cross-linking agent, and D230 polyetheramine is used in the implementation process; 8.5 parts of water.

[0028] Step S1: Add the reinforced bio-based filler, catalyst, foam stabilizer, pore opening agent, cross-linking agent and water into a mixer and premix at 600 rpm for 5 minutes, then add the polyurethane prepolymer and continue mixing for 3 minutes to obtain a polyurethane foam material.

[0029] Step S2: inject the foaming material into the mold, foam it at 60° C. for 65 minutes, then continue to heat it to 110° C. and continue to foam it for 35 minutes, demold and dry it to obtain a bio-based environmentally friendly breathable insole.

[0030] Example 3, preparing a bio-based environmentally friendly breathable insole, the specific implementation process is as follows: (1) Preparation of enhanced bio-based fillers Step A1: Take diethanolamine and dioxane and mix them, introduce nitrogen protection, heat to 45°C, apply stirring at 90rpm, slowly add formaldehyde to react for 1.8h, then add p-toluenesulfonic acid to mix, heat to 100°C, reflux to separate water, react for 2.5h, and remove dioxane by rotary evaporation to obtain an intermediate, wherein formaldehyde is added in the formaldehyde solution with a mass fraction of 40%, and the dosage ratio of diethanolamine, formaldehyde, p-toluenesulfonic acid and dioxane is 0.1mol:0.13mol:0.12g:40mL.

[0031] Step A2: Take the intermediate and dichloroethane and mix them, pass dry nitrogen for protection, control the temperature at 5°C in an ice-water bath, apply stirring at 180rpm, slowly add vinyltrichlorosilane to react for 2.6h, then add sodium hydroxide and mix, raise the temperature to 70°C and continue to react for 1.3h. After the reaction is completed, filter and remove dichloroethane by rotary evaporation to obtain a modifier, wherein the amount ratio of the intermediate, vinyltrichlorosilane, sodium hydroxide and dichloroethane is 0.1mol:0.38mol:1.5g:70mL.

[0032] Step A3: Mix the silane coupling agent KH-580 and the ethanol solution, adjust the pH value to 3 with formic acid, stir and hydrolyze for 0.7h, add the lignin fiber and mix and beat for 2.8h, neutralize with ammonia water and let stand for 24h, remove the supernatant and dry to obtain coupled fibers, wherein the volume concentration of the ethanol solution is 40% aqueous solution, the lignin fiber is commercially available with an average fiber length of 3mm, and the amount ratio of lignin fiber, silane coupling agent KH-580 and ethanol solution is 50g:2.8g:65mL.

[0033] Step A4: Take the premix of modifier, photoinitiator, ethyl acetate and acetone, add the coupled fiber and mix, heat to 55°C, apply 120 rpm stirring and 180 W / m 2 The mixture was irradiated with ultraviolet light and reacted for 4.2 hours. After the reaction, the mixture was filtered and dried to obtain a reinforced bio-based filler, wherein the amount ratio of the coupling fiber, the modifier, the photoinitiator, the ethyl acetate and the acetone was 50 g: 4.2 g: 0.2 g: 30 mL: 60 mL.

[0034] (2) Preparation of bio-based environmentally friendly breathable insoles Ingredients: The raw materials are calculated according to weight: 100 parts of polyurethane prepolymer, and H2128A prepolymer raw material is used in the implementation process; 12 parts of reinforced bio-based filler, which is homemade in this embodiment; 0.25 parts of catalyst, and dibutyltin dilaurate is used in the implementation process; 0.5 parts of foam stabilizer, and L-580 silicone oil is used in the implementation process; 0.7 parts of pore opener, and K340 soft foam pore opener is used in the implementation process; 1.2 parts of cross-linking agent, and D230 polyetheramine is used in the implementation process; 7.2 parts of water.

[0035] Step S1: Add the reinforced bio-based filler, catalyst, foam stabilizer, pore opening agent, cross-linking agent and water into a mixer and premix at 600 rpm for 5 minutes, then add the polyurethane prepolymer and continue mixing for 3 minutes to obtain a polyurethane foam material.

[0036] Step S2: inject the foaming material into the mold, foam it at 70° C. for 60 minutes, then continue to heat it to 120° C. for further foaming for 30 minutes, demold and dry it to obtain a bio-based environmentally friendly breathable insole.

[0037] Comparative Example 1 This comparative example refers to Example 3, except that the reinforced bio-based filler is replaced with the same weight portion of lignin fiber, 0.5 parts of a cross-linking agent is added, and the rest of the implementation process is exactly the same.

[0038] Comparative Example 2 In this comparative example, silane coupling agent KH-550 is used to treat the surface of lignin fiber to prepare amino filler, and bio-based environmentally friendly breathable insoles are prepared by compounding, wherein the preparation method of the amino filler is as follows: silane coupling agent KH-550 and ethanol solution are mixed, pH value is adjusted to 3 with acetic acid, stirred and hydrolyzed for 0.8h, lignin fiber is added and mixed and pulped for 3h, after neutralization, it is allowed to stand and age for 24h, the supernatant is removed and dried, wherein the amount ratio of lignin fiber, silane coupling agent KH-550 and ethanol solution is 50g:3.5g:80mL; the reinforced bio-based filler is replaced with the same weight portion of amino filler, and the rest of the implementation process is exactly the same.

[0039] Samples were taken from the insoles prepared as above, and the density was tested according to the HG / T 2872-2009 standard; the tensile performance was tested according to the GB / T10654-2001 standard; the tearing performance was tested according to the GB / T 10808-2006 standard; the resilience was tested according to the HG / T4993-2016 standard; the air permeability of the samples was tested using a fully automatic air permeability tester, the test gas was compressed air, and the air pressure was 2.0 bar; the specific test results are shown in the following table:

[0040] It can be seen from the test results in the above table that the insole prepared in the embodiment has a low density, good foaming, and its tensile strength and tear strength are significantly better than those of the comparative example. It shows excellent mechanical strength, excellent resilience, and maintains good air permeability. Its comprehensive performance is significantly better than that of existing polyurethane foam insoles.

[0041] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", 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 does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0042] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A bio-based environmentally friendly breathable insole, formed by foaming polyurethane foam, characterized in that: The polyurethane foaming material comprises, by weight: 100 parts of polyurethane prepolymer, 9-14 parts of reinforced bio-based filler, 0.2-0.3 parts of catalyst, 0.4-0.5 parts of foam stabilizer, 0.7-0.9 parts of cell opener, 1.1-1.3 parts of crosslinking agent and 6.5-8.5 parts of water; The reinforced bio-based filler is prepared by the following method: Step A1: diethanolamine and dioxane are mixed, nitrogen is introduced for protection, the temperature is raised to 40-50°C, formaldehyde is slowly added with stirring for reaction for 1.5-2h, p-toluenesulfonic acid is then added and mixed, the temperature is raised to 100-105°C, refluxed to separate water, the reaction is carried out for 2.2-2.8h, and dioxane is removed by rotary evaporation to obtain an intermediate; Step A2: The intermediate and dichloroethane are mixed, and dry nitrogen is introduced for protection. The temperature is controlled at 5-15°C in an ice-water bath. Vinyltrichlorosilane is slowly added with stirring for 2-3h, and then sodium hydroxide is added and mixed. The temperature is raised to 65-75°C and the reaction is continued for 1-1.5h. After the reaction is completed, the dichloroethane is removed by filtration and rotary evaporation to obtain a modifier; Step A3: Mix the silane coupling agent KH-580 and the ethanol solution, adjust the pH value to 3-4, stir and hydrolyze for 0.6-0.8h, add the lignin fiber and mix and beat for 2.5-3h, stand and age for 24h after neutralization, remove the supernatant and dry to obtain coupled fiber; Step A4: premix the modifier, photoinitiator, ethyl acetate and acetone, add the coupled fiber and mix, heat to 50-60°C, stir and apply 150-200W / m 2 The reaction was carried out under ultraviolet irradiation for 3.5-4.5 hours. After the reaction was completed, the mixture was filtered and dried to obtain a reinforced bio-based filler.

2. The bio-based environmentally friendly breathable insole according to claim 1, characterized in that: The usage ratio of diethanolamine, formaldehyde, p-toluenesulfonic acid and dioxane is 0.1 mol: 0.12-0.14 mol: 0.1-0.15 g: 35-45 mL.

3. The bio-based environmentally friendly breathable insole according to claim 2, characterized in that: The usage ratio of the intermediate, vinyltrichlorosilane, sodium hydroxide and dichloroethane is 0.1 mol: 0.35-0.4 mol: 1.2-1.6 g: 60-70 mL.

4. The bio-based environmentally friendly breathable insole according to claim 1, characterized in that: The dosage ratio of lignin fiber, silane coupling agent KH-580 and ethanol solution is 50g:2.4-3.2g:55-70mL.

5. A bio-based, environmentally friendly, breathable insole according to any one of claims 3-4, characterized in that: The usage ratio of the coupling fiber, the modifier, the photoinitiator, the ethyl acetate and the acetone is 50 g: 3.8-4.4 g: 0.2-0.3 g: 25-40 mL: 55-70 mL.

6. The production process of a bio-based environmentally friendly breathable insole according to claim 5, characterized in that: Including the following processes: Step S1: premixing a reinforced bio-based filler, a catalyst, a foam stabilizer, a cell opening agent, a crosslinking agent and water, and then adding a polyurethane prepolymer and mixing well to obtain a polyurethane foam material; Step S2: inject the foaming material into the mold, foam it at 60-80° C. for 50-65 minutes, then heat it to 110-120° C. and continue foaming for 25-35 minutes, demold and dry it to obtain a bio-based environmentally friendly breathable insole.

7. The production process of a bio-based environmentally friendly breathable insole according to claim 6, characterized in that: The catalyst is dibutyltin dilaurate.

8. The production process of a bio-based environmentally friendly breathable insole according to claim 6, characterized in that: The crosslinking agent is D230 polyetheramine.

Images