CN117164809A - Bio-based polyurethane composite material applied to insoles and preparation method thereof - Google Patents

Abstract

This application relates to the field, and specifically discloses a bio-based polyurethane composite material used in insoles and a preparation method thereof. The bio-based polyurethane composite material consists of component A and component B, and component A is prepared from the following raw materials by weight: 42 to 62 parts of bio-based polyol, 3 to 6 parts of chain extender, 1 to 2 parts of stabilizer, 0.5 to 1.5 parts of catalyst, and 0.2 to 0.4 parts of water; component B is prepared from the following raw materials by weight: diisocyanate 20 to 40 parts, polycaprolactone polyol 5 to 15 parts, antibacterial additive 5 to 10 parts, antioxidant 0.1 to 0.3 parts; preparation method: mix each raw material and heat and vacuum to prepare component A; The raw materials are mixed, heated and evacuated to prepare component B. The preparation method of the present application is simple, and the bio-based polyurethane composite material produced has good biodegradability and system stability. When used in insoles, it has good elasticity, is not easy to deform, and has good antibacterial, deodorizing and environmental protection properties.

Description

A kind of bio-based polyurethane composite material used in insoles and preparation method thereof

Technical field

The present application relates to the field of bio-based polyurethane materials, and more specifically, it relates to a bio-based polyurethane composite material used in insoles and a preparation method thereof.

Background technique

Polyurethane material has excellent physical properties and good processing properties, and is widely used in insoles.

Polyurethane materials are produced by the reaction of polyols containing alcoholic hydroxyl groups and isocyanates. Commonly used polyols include polyether polyols and polyester polyols, and these raw materials are derived from non-renewable petroleum raw materials. They are made from this polyol. Polyurethane has low degradability and low environmental protection. Therefore, some studies have proposed using bio-based polyols instead of general polyols to prepare polyurethane materials.

Common bio-based polyols are generally derived from vegetable oils, plant fibers, polylactic acid fibers, etc. Polyurethane materials made using these bio-based polyols have good biodegradability, but their mechanical properties are lower than those of general polyols. , after the polyurethane materials prepared from these bio-based polyols are used in insoles, the insoles are prone to deformation and low elasticity after being used for a period of time, and the insoles are prone to breed a lot of bacteria during use, resulting in stinky feet. situation, reducing the application of bio-based polyurethane materials in insoles.

Contents of the invention

In order to solve the problems that conventionally used bio-based polyurethane materials used in insoles are easy to deform, have low elasticity and are prone to breed bacteria, this application provides a bio-based polyurethane composite material used in insoles and a preparation method thereof.

In the first aspect, this application provides a bio-based polyurethane composite material used in insoles, adopting the following technical solution:

A bio-based polyurethane composite material used in insoles, consisting of component A and component B. The component A is prepared from the following raw materials by weight: 42 to 62 parts of bio-based polyol and 3 to 6 parts of chain extender. 6 parts, 1 to 2 parts of stabilizer, 0.5 to 1.5 parts of catalyst, and 0.2 to 0.4 parts of water; the B component is prepared from the following raw materials by weight: 20 to 40 parts of diisocyanate, 5 polycaprolactone polyols ~15 parts, 5-10 parts of antibacterial additives, and 0.1-0.3 parts of antioxidants.

By adopting the above technical solution, the bio-based polyurethane composite material of the present application is composed of component A and component B. The component A and component B are stored separately, and the system performance is stable. When used in insoles, component A and component B are Component B is mixed and reacted at a dosage ratio of 1:(0.82-0.92). The insole prepared by this method has better elasticity, smaller permanent compression deformation rate, antibacterial property and biodegradability.

During the mixing reaction, under the action of the catalyst, bio-based polyols and polycaprolactone polyols provide alcohol hydroxyl groups, which can react with diisocyanate. The chain extender plays a better chain extension and cross-linking effect, which can further improve the production process. The elasticity and compression deformation resistance of the obtained insole, water is used as a foaming agent, and the stabilizer has the function of stabilizing the system reaction and uniform foaming. Under the action of the stabilizer, the system reacts stably and foams, and the obtained insole It has good elasticity and resistance to compression deformation. The antioxidant has good antioxidant effect and can improve the weather resistance of the insole. The antibacterial additive has good antibacterial properties. When added to component B, it can While having a good antibacterial effect, it can also further improve the biodegradability of the prepared bio-based polyurethane composite material used in insoles.

Preferably, the bio-based polyol is prepared from the following raw materials by weight: 20 to 35 parts of epoxidized soybean oil, 40 to 60 parts of diethylene glycol, and 0.05 to 0.15 parts of catalyst.

By adopting the above technical solution, epoxidized soybean oil and diethylene glycol undergo a hydroxylation reaction under the action of a catalyst to prepare a bio-based polyol containing soybean oil. The main component of the bio-based polyol prepared in this application is The chain contains ester groups and the side chain contains long linear ether groups. Compared with conventionally used polyether polyols and polyester polyols, the molecular structure has better flexibility and multi-branched network structure, combining polyether polyols. The excellent properties of alcohol and polyester polyol have good softness, elasticity and biodegradability. The bio-based polyurethane composite material made with this material has good elasticity, compression deformation resistance and environmental protection when used in insoles. sex.

Preferably, the bio-based polyol is prepared by the following steps:

A1. In parts by weight, add 20 to 35 parts of epoxidized soybean oil, 40 to 60 parts of diethylene glycol and 0.05 to 0.15 parts of catalyst into the reaction equipment, raise the temperature to 90 to 110°C, and react for 3 to 5 hours;

A2. After cooling to 25~35°C, let it stand to separate the oil phase. Add 10~20 parts of 5~15wt% sodium carbonate aqueous solution to the oil phase for washing, then wash with water until pH=8~9, and continue to separate the oil. phase, the oil phase is distilled under reduced pressure to obtain bio-based polyol; the catalyst is concentrated sulfuric acid.

By adopting the above technical solution, firstly, under optimal conditions, concentrated sulfuric acid is used as a catalyst to react epoxidized soybean oil and diethylene glycol to prepare a soybean oil-based bio-based polyol. The sodium carbonate aqueous solution with a higher concentration in the alcohol is then washed to remove acid impurities in the soybean oil-based polyol, and then distilled under reduced pressure to remove low-boiling point impurities in the soybean oil-based polyol, thereby preparing a bio-based polyol. .

Preferably, the antibacterial auxiliary agent is composed of zinc ricinoleate, castor oil and a long-chain alkyl silane coupling agent in a dosage ratio of 1: (0.4-0.6): (2-3).

By adopting the above technical solution, zinc ricinoleate is an antibacterial material containing active zinc, castor oil is a vegetable oil containing polyhydroxyl groups, and using castor oil as the dispersion carrier of zinc ricinoleate can stably disperse zinc ricinoleate. The long-chain alkyl silane coupling agent is compounded with a better proportion of zinc ricinoleate, castor oil and long-chain alkyl silane coupling agent. Under the synergistic effect of the three, the antibacterial additive prepared It can be stably dispersed into component B. The antibacterial additive can further cross-link with diisocyanate. When the bio-based polyurethane composite material is used in insoles, it can improve the antibacterial properties and biodegradability of insoles. It can also further improve the elasticity and compression deformation resistance of the insole.

Preferably, the chain extender is one or a combination of ethylene glycol, butylene glycol, trimethylolpropane, ethylenediamine, hexamethylenediamine and isophoronediamine.

By adopting the above technical solution, the chain extender can further perform a cross-linking reaction with diisocyanate, causing the polyurethane composite material to react to form a network cross-linked structure of macromolecules, further improving the elasticity and compression deformation resistance of the insole produced. .

Preferably, the stabilizer consists of polyether-modified silicone and glyceryl cocoate in a dosage ratio of 1: (0.1-0.3).

By adopting the above technical solution, a better proportion of polyether-modified silicone and glyceryl cocoate can improve the uniformity and reaction stability of polyurethane composite foaming, form a uniform and stable foaming system, and improve the foaming properties. The insole has uniform elasticity and resistance to permanent compression deformation.

Preferably, the diisocyanate is one or a combination of toluene diisocyanate, polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate and liquefied MDI.

By adopting the above technical solution, the above-mentioned diisocyanate provides isocyanate groups and polyol hydroxyl groups for reaction, and the prepared bio-based polyurethane composite material has good reaction stability. When used in insoles, it can react stably and develop evenly. Foam, the insole formed by this has better elasticity and resistance to permanent compression deformation.

Preferably, the catalyst is composed of an organotin catalyst and a tertiary amine catalyst with a dosage ratio of 1: (0.5 to 0.8). The organotin catalyst is stannous octoate, stannous oleate and dibutyltin dilaurate. Any one of the esters, the tertiary amine catalyst is any one of triethylenediamine, dimethylethanolamine, N-methylmorpholine and N,N-dimethylcyclohexylamine.

By adopting the above technical solution and using a better proportion of tertiary amine catalysts and organotin catalysts as reaction catalysts, the stability and sufficiency of the reaction can be improved, and a bio-based polyurethane composite material for insoles with stable performance can be prepared. .

In the second aspect, this application provides a method for preparing bio-based polyurethane composite materials applied to insoles, adopting the following technical solution:

A method for preparing bio-based polyurethane composite materials applied to insoles, including the following preparation steps:

Add the bio-based polyol and chain extender into the reaction equipment, raise the temperature, evacuate, and stir evenly. After cooling, add stabilizer, catalyst and water, stir evenly, then discharge and seal for storage to prepare component A;

Add diisocyanate, polycaprolactone polyol and antibacterial additives to the reaction equipment, raise the temperature and evacuate, add antioxidant after stirring and reaction, stir evenly, cool down, discharge and seal to store, to prepare component B.

By adopting the above technical solution, the bio-based polyol and the chain extender are uniformly mixed and dispersed under the conditions of heating and vacuuming, and then the temperature is cooled down after uniform dispersion. The purpose of cooling is for the stability of the system. After adding stabilizer, catalyst and water for uniform dispersion, component A of the bio-based polyurethane composite material is prepared; polycaprolactone, diisocyanate and antibacterial additives are uniformly mixed and dispersed under heating and vacuum conditions, and then Add antioxidants to prepare the B component of the bio-based polyurethane composite material. The A component and B component thus prepared are separate stable systems, which are easy to store and can be mixed and reacted according to the proportion during use.

Preferably, in the preparation step of component A, the heating temperature is 60~75°C, the vacuum degree of vacuuming is -0.05~-0.08MPa, the first stirring time is 1~2h, and the cooling temperature is 20~35°C. , the second stirring time is 30~60min; in the preparation step of component B, the heating temperature is 70~85°C, the vacuum degree is -0.05~-0.08MPa, and the first stirring time is 1~3h , the second stirring time is 10~30min, and the cooling temperature is 20~35℃.

By adopting the above technical solution, better mixing conditions can produce component A and component B of bio-based polyurethane composite materials with stable performance and system.

To sum up, this application has the following beneficial effects:

1. This application is a bio-based polyurethane composite material used in insoles, which uses bio-based polyol, chain extender, stabilizer, catalyst and water as component A, and diisocyanate, polycaprolactone polyol, antibacterial assistant Agents and antioxidants are used as component B. When used in insoles, component A and component B are mixed and reacted in a better ratio. The insole produced has better elasticity, resistance to compression deformation, and antibacterial properties. and biodegradability.

2. By using epoxidized soybean oil, diethylene glycol and concentrated sulfuric acid catalyst to react, and after alkali washing separation, water washing separation and vacuum distillation, bio-based polyols containing soybean oil are obtained. The main chain of the bio-based polyols contains The ester group and side chain contain long linear ether groups, and the molecular structure has good softness and multi-branched network structure. The bio-based polyurethane composite material prepared by this method is used in insoles and has good elasticity and resistance to compression deformation. safety and environmental protection.

3. By using a better proportion of zinc ricinoleate, castor oil and long-chain alkyl silane coupling agent as antibacterial additives, and using castor oil as the dispersion carrier of zinc ricinoleate, zinc ricinoleate can be stably dispersed. To the long-chain alkyl silane coupling agent, under the synergistic effect of the three, the antibacterial additive can be further cross-linked with diisocyanate, and the bio-based polyurethane composite material can be used in insoles , while improving the antibacterial and biodegradability of the insole, it can also further improve the elasticity and compression deformation resistance of the insole.

4. The preparation method of this application is simple and easy to operate, and a two-component bio-based composite material can be prepared, stored separately, and has stable performance and system.

Detailed ways

The present application will be further described in detail below in conjunction with examples.

The following are the sources and specifications of some of the raw materials of this application. The raw materials used in the preparation examples and examples of this application are all commercially available:

1. Epoxidized soybean oil: molecular weight 1000, epoxy value greater than 6%;

2. Diethylene glycol: diethylene glycol ether, density 1.106g/cm ³ ;

3. Zinc ricinoleate: purity 98%, industrial grade, white powder;

4. Castor oil: molecular weight 930-935, content 99.9%, hydroxyl content 5%, average hydroxyl functionality 2.7;

5. Polyether modified silicone: Dow DC5043;

6. Cocoyl glyceryl ester: PEG-7, content 98%;

7. Polycaprolactone polyol: Polycaprolactone glycol, molecular weight 2000, hydroxyl value 56 mgKOH/g, melting point 45-55°C.

Preparation examples of bio-based polyols

Preparation Example 1

Preparation Example 1 discloses a bio-based polyol, which is prepared by the following steps:

A1. Add 2kg epoxidized soybean oil, 4kg diethylene glycol and 5g concentrated sulfuric acid as catalysts into the reactor, raise the temperature to 90°C, and react for 3 hours;

A2. After cooling to 25°C, let it stand to separate the oil phase. Add 1kg 5wt% sodium carbonate aqueous solution to the oil phase for washing, and then wash it with water 2-3 times until pH=8. Continue to separate the oil phase. The oil phase is distilled under reduced pressure to remove low-boiling point impurities in the oil phase to obtain bio-based polyol.

Preparation Example 2-3

Preparation Example 2-3 discloses a bio-based polyol. The difference from Preparation Example 1 is that the preparation conditions and the amount of raw materials are different. For details, see Table 1 below.

Table 1 Raw material dosage and preparation conditions of Preparation Examples 1-3

Preparation Comparative Example 1

Preparation Comparative Example 1 discloses a bio-based polyol. The difference from Preparation Example 1 is that an equal amount of diethylene glycol is replaced by ethylene glycol, and the rest is the same as Preparation Example 1.

Example

Example 1

Embodiment 1 discloses a bio-based polyurethane composite material applied to insoles, which is prepared by the following preparation steps:

Add 4.2kg of commercially available bio-based polyol and 0.3kg of ethylene glycol as chain extenders into the reaction kettle, raise the temperature to 60°C, vacuum, the vacuum degree is -0.05MPa, stir for 1 hour, and stir evenly. After cooling to 20°C, add a stabilizer composed of 0.05kg polyether modified silicone and 0.05kg cocoglyceryl ester, 33.33g stannous octoate as an organotin catalyst, and 16.67g triethylenediamine as a tertiary amine catalyst. Stir the catalyst and 20g of water for 30 minutes, stir evenly, then discharge and seal and store to prepare component A. Among them, the hydroxyl value of commercially available bio-based polyol is 45-60mg KOH/g, and the viscosity is 800-1500mPa.s;

2kg of toluene diisocyanate as the diisocyanate, 0.5kg of polycaprolactone polyol and 0.1kg of zinc ricinoleate, 0.1kg of castor oil and 0.3kg of dodecyltrimethoxysilane as the long chain alkyl silane coupling agent were mixed The prepared antibacterial additive was added to the reaction kettle, heated to 70°C, and evacuated. The degree of vacuum was -0.05MPa, and the stirring time was 1 hour. After the stirring reaction, 10g of antioxidant 1010 was added, and stirred for 10 minutes. After uniformity, the temperature is lowered to 20°C, the material is discharged and sealed for storage to prepare component B.

Example 2-3

Example 2-3 discloses a bio-based polyurethane composite material applied to insoles. The difference from Example 1 is that the amount of raw materials and preparation conditions are different. See Table 2 below for details.

Table 2 Raw material dosage and preparation conditions of Examples 1-3

Example 4-7

Examples 4-7 disclose a bio-based polyurethane composite material applied to insoles. The difference from Example 1 is that the source of the bio-based polyol is different. See Table 3 below for details.

Table 3 Source list of bio-based polyols of Examples 4-7

Example Bio-based polyol sources Example 4 Preparation Example 1 Example 5 Preparation Example 2 Example 6 Preparation Example 3 Example 7 Preparation Comparative Example 1

Example 8

Embodiment 8 discloses a bio-based polyurethane composite material applied to insoles. The difference from Embodiment 4 is that the proportion of antibacterial additives is different, and the dosage ratio of zinc ricinoleate, castor oil and dodecyltrimethoxysilane is different. It is 1:0.4:2, and the others are the same as Example 4.

Example 9

Embodiment 9 discloses a bio-based polyurethane composite material applied to insoles. The difference from Embodiment 4 is that the proportion of antibacterial additives is different, and the dosage ratio of zinc ricinoleate, castor oil and dodecyltrimethoxysilane is different. It is 1:0.6:3, and the others are the same as Example 4.

Example 10

Embodiment 10 discloses a bio-based polyurethane composite material used in insoles. The difference from Embodiment 8 is that the ratio of stabilizers is different. The dosage ratio of polyether-modified silicone and cocoglyceryl ester is 1:0.1. Others are the same as Example 8.

Example 11

Example 11 discloses a bio-based polyurethane composite material used in insoles. The difference from Example 8 is that the ratio of stabilizers is different. The dosage ratio of polyether-modified silicone and cocoglyceryl ester is 1:0.3. Others are the same as Example 8.

Example 12

Example 12 discloses a bio-based polyurethane composite material used in insoles. The difference from Example 4 is that the antibacterial auxiliary agent is different. Castor oil is replaced by dodecyltrimethoxysilane in equal amounts. The other differences are the same as those in Example 4. same.

Example 13

Example 13 discloses a bio-based polyurethane composite material applied to insoles. The difference from Example 4 is that the stabilizer is different. An equal amount of cocoglyceryl ester is replaced by polyether-modified silicone. The other differences are the same as those in Example 4. same.

Comparative ratio

Comparative example 1

Comparative Example 1 discloses a bio-based polyurethane composite material applied to insoles. The difference from Example 1 is that the antibacterial agent is a commercially available quaternary ammonium salt antibacterial agent (benzalkonium chloride), and the rest is the same as Example 1.

Application examples

Application example 1

Application Example 1 discloses an insole. The A component and the B component of the bio-based polyurethane composite material prepared in Example 1 are mixed and stirred in a mass ratio of 1:0.82 for 30 minutes and then added to the mold at a temperature of Reaction and aging are carried out at 70°C. After aging for 30 minutes, the mold is opened and cut to obtain an insole with a thickness of 0.45±0.02cm.

Application Example 2-3

Application Example 2-3 discloses an insole. The difference from Example 1 is that the processing conditions are different and the source of the bio-based polyurethane composite material is also different. For details, see Table 4 below.

Table 4 Preparation conditions table of application examples 1-3

Application example 4-15

Application Example 4-15 discloses an insole. The difference from Application Example 1 is that the source of the bio-based polyurethane composite material is different. See Table 5 below for details.

Table 5 Source list of bio-based polyurethane composite materials in application examples 4-15

Application examples Source of bio-based polyurethane composite materials Application example 4 Example 4 Application example 5 Example 5 Application example 6 Example 6 Application example 7 Example 7 Application example 8 Example 8 Application example 9 Example 9 Application example 10 Example 10 Application example 11 Example 11 Application example 12 Example 12 Application example 13 Example 13 Application example 14 Comparative example 1

Performance Testing Test The performance test of the insole prepared in Application Example 1-14 is as follows:

(1) Flexibility test:

Referring to the test method in GB/T 1681, use a rebound testing machine to test the elasticity (unit: %) of the insole, detect and record the test results;

(2)Permanent compression deformation rate test:

Referring to the test method of ASTM D395-B-2003, use a compression testing machine to test the compression deformation (unit: %) of the insole, detect and record the test results;

(3) Antibacterial performance test:

Referring to the test methods in QB/T 5191-2017 and QB/T 2881-2013, use commercial laundry detergent to wash the insoles 10 times, and then conduct the Staphylococcus aureus and Candida albicans antibacterial rate (unit: %) test. and record the test results;

(4) Biobased content test:

The biobased content (unit: %) of the prepared insoles was tested with reference to ASTM D6866-21 Method B (AMS) "Standard Test Method for Determination of Biobased Content in Solid, Liquid, and Gas Samples by Radiocarbon Analysis", and the test was carried out. Record test results;

The following is the test data of elasticity, permanent compression deformation rate, antibacterial property and bio-based content of the insoles prepared in Application Examples 1-14. For details, see Table 6 below.

Table 6 Performance test data table of insoles of application examples 1-14

Combining Application Examples 1-3 and Application Examples 4-7 and Table 6, it can be seen that the bio-based polyurethane composite material prepared by using the bio-based polyol prepared by the preparation method of the present application is used in insoles. The elasticity of the insole is relatively increased by up to 5%, the permanent compression deformation rate is reduced by 2.5%, and the bio-based content is increased by 2.4%. In Application Example 7, the same amount of diethylene glycol is replaced by ethylene glycol, and the performance of the insole obtained is obvious reduce.

Combining Application Examples 4-6, Application Examples 8-9, Application Example 12 and Comparative Example 1 and Table 6, it can be seen that using the zinc ricinoleate, castor oil and long-chain alkyl silane coupling agent of the present application as an antibacterial Additives, the insoles made of the bio-based polyurethane composite material have good elasticity, small permanent compression deformation, good antibacterial properties and good biodegradability. In Application Examples 8-9, a better proportion of antibacterial additives is used. agent, the performance is improved. However, in Application Example 12, castor oil is not added. Compared with Application Example 4, the performance of the insole prepared is lower in elasticity, higher permanent compression deformation rate, significantly lower antibacterial properties, and lower biodegradability. , in Comparative Example 1, conventional quaternary ammonium salt antibacterial agents were used, and all properties were significantly reduced.

Combining Application Example 4, Application Examples 8-9, Application Examples 10-11 and Application Example 13 and Table 6, it can be seen that the performance of the insole prepared by using a better proportion of stabilizer is better, while the performance of the insole prepared by using the stabilizer in 13 is not good. Adding cocoglyceryl ester reduces the performance of the insole produced.

This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contribution as needed, but as long as the rights of this application are All requirements are protected by patent law.

Claims (10)

1. The bio-based polyurethane composite material for the shoe pads is characterized by comprising a component A and a component B, wherein the component A is prepared from the following raw materials in parts by weight: 42 to 62 parts of bio-based polyol, 3 to 6 parts of chain extender, 1 to 2 parts of stabilizer, 0.5 to 1.5 parts of catalyst and 0.2 to 0.4 part of water; the component B is prepared from the following raw materials in parts by weight: 20-40 parts of diisocyanate, 5-15 parts of polycaprolactone polyol, 5-10 parts of antibacterial auxiliary agent and 0.1-0.3 part of antioxidant.

2. The bio-based polyurethane composite for shoe insoles according to claim 1, wherein the bio-based polyol is prepared from the following raw materials in parts by weight: 20 to 35 parts of epoxidized soybean oil, 40 to 60 parts of diglycol and 0.05 to 0.15 part of catalyst.

3. A biobased polyurethane composite for shoe insoles according to claim 2, wherein the biobased polyol is prepared by the steps of:

a1, adding 20-35 parts of epoxidized soybean oil, 40-60 parts of diethylene glycol and 0.05-0.15 part of catalyst into reaction equipment according to parts by weight, heating to 90-110 ℃ and reacting for 3-5 hours;

a2, cooling to 25-35 ℃, standing to separate an oil phase, adding 10-20 parts of 5-15 wt% sodium carbonate aqueous solution into the oil phase for washing, washing until the pH value is 8-9, continuously separating the oil phase, and carrying out reduced pressure distillation on the oil phase to obtain the bio-based polyol; the catalyst is concentrated sulfuric acid.

4. The bio-based polyurethane composite material applied to insoles according to claim 1, wherein the antibacterial auxiliary agent is formed by mixing zinc ricinoleate, castor oil and a long-chain alkyl silane coupling agent in a dosage ratio of 1 (0.4-0.6): 2-3.

5. The bio-based polyurethane composite for shoe insoles according to claim 1, wherein the chain extender is one or a combination of ethylene glycol, butylene glycol, trimethylol propane, ethylene diamine, hexamethylene diamine and isophorone diamine.

6. The bio-based polyurethane composite material for shoe pads according to claim 1, wherein the stabilizer consists of polyether modified organosilicon and coco glyceride with a dosage ratio of 1 (0.1-0.3).

7. The bio-based polyurethane composite for shoe insoles according to claim 1, wherein the diisocyanate is one or a combination of toluene diisocyanate, polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate and liquefied MDI.

8. The bio-based polyurethane composite material applied to insoles according to claim 1, wherein the catalyst comprises an organotin catalyst and a tertiary amine catalyst in a dosage ratio of 1 (0.5-0.8), wherein the organotin catalyst is any one of stannous octoate, stannous oleate and dibutyltin dilaurate, and the tertiary amine catalyst is any one of triethylenediamine, dimethylethanolamine, N-methyl morpholine and N, N-dimethyl cyclohexane.

9. A method for preparing a bio-based polyurethane composite for insole according to any one of claims 1 to 8, comprising the following steps:

adding the biological polyol and the chain extender into reaction equipment, heating, vacuumizing, uniformly stirring, cooling, adding the stabilizer, the catalyst and water, uniformly stirring, discharging, and sealing for preservation to obtain a component A;

adding diisocyanate, polycaprolactone polyol and an antibacterial auxiliary agent into reaction equipment, heating, vacuumizing, stirring, adding an antioxidant after the reaction, uniformly stirring, cooling, discharging, and sealing for preservation to obtain the component B.

10. The bio-based polyurethane composite material for shoe pads according to claim 9, wherein in the step of preparing the component A, the temperature is raised to 60-75 ℃, the vacuum degree of vacuumizing is minus 0.05 to minus 0.08MPa, the first stirring time is 1-2 h, the temperature is lowered to 20-35 ℃, and the second stirring time is 30-60 min; in the preparation step of the component B, the temperature is raised to 70-85 ℃, the vacuumizing vacuum degree is minus 0.05-minus 0.08MPa, the first stirring time is 1-3 h, the second stirring time is 10-30 min, and the cooling temperature is 20-35 ℃.