Method for modifying biomass-based waterborne polyurethane by using organic silicon

Abstract

The invention relates to a method for modifying biomass-based waterborne polyurethane by using organic silicon, and belongs to the technical field of high polymer materials, biomass utilization and environment-friendly coatings. The invention relates to a method for modifying biomass-based waterborne polyurethane by using organic silicon, which comprises the following steps: S1, carrying out liquefaction treatment on banana peel to obtain biomass-based polyol; s2, uniformly mixing the obtained biomass-based polyol with polyether polyol, isocyanate, hydroxyl silicone oil, 1, 4-butanediol and dibutyltin dilaurate, so as to obtain a mixed raw material; and S3, preparing the waterborne polyurethane by taking the mixed raw material prepared in the step S2, N, N-dimethylformamide, 2, 2-dimethylolpropionic acid, triethylamine, ethidene diamine and distilled water as raw materials. The method solves the problems that traditional waterborne polyurethane is low in tensile strength, poor in water resistance and non-degradable.

Description

Technical Field

[0001] The invention relates to a method for modifying biomass-based waterborne polyurethane using organic silicon, and belongs to the technical fields of polymer materials, biomass utilization and environmentally friendly coatings. Background Art

[0002] Nowadays, researchers often coat textile surfaces with functional polymer materials to meet consumers' demand for comfort, convenience, and functionality. Among them, polyurethane coatings are often used in the preparation of textiles due to their excellent wear resistance, flexibility, and corrosion resistance. However, traditional textiles mostly use solvent-based polyurethane coatings, which have the problem of volatile organic compound pollution. Therefore, solvent-based polyurethane coatings have gradually been replaced by water-based polyurethane coatings. However, water-based polyurethane coatings still have some disadvantages, such as low tensile strength, poor water resistance, and non-degradability.

[0003] To address these deficiencies, it is necessary to modify waterborne polyurethane to meet its application requirements. Currently, methods for modifying waterborne polyurethane primarily include silicone modification, epoxy resin modification, acrylate modification, crosslinking modification, and nanomaterial modification. Silicone-modified waterborne polyurethane has been a research hotspot in recent years. Silicone is a polymer with a -Si-O-Si- backbone and side chains consisting of organic structures connected to silicon atoms. This unique chemical structure allows silicone to combine the advantages of both inorganic and organic materials. Furthermore, silicone has a relatively low surface energy, which gives silicone-modified waterborne polyurethane films excellent waterproofing and mechanical properties. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for modifying biomass-based waterborne polyurethane using organosilicon, which solves the problems of low tensile strength, poor water resistance and non-degradability of traditional waterborne polyurethane.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A method for modifying biomass-based waterborne polyurethane using organosilicon, the method comprising the following steps: S1, liquefying banana peels to obtain biomass-based polyols; S2, uniformly mixing the obtained biomass-based polyols with polyether polyols, isocyanate, hydroxy silicone oil, 1,4-butanediol, and dibutyltin dilaurate to obtain a mixed raw material; S3, preparing waterborne polyurethane using the mixed raw material obtained in S2, N,N-dimethylformamide, 2,2-dihydroxymethylpropionic acid, triethylamine, ethylenediamine, and distilled water as raw materials.

[0007] Due to the depletion of fossil fuel resources, the use of renewable resources to replace petroleum feedstocks in the production of waterborne polyurethanes has attracted widespread attention. Biomass-based polyols obtained by liquefying discarded banana peels are high-quality raw materials for preparing waterborne polyurethanes. Based on this, the present invention obtains biomass-based polyols by liquefying discarded banana peels and introduces hydroxyl silicone oil as a modifier to form an organic-inorganic hybrid structure, resulting in a final product with excellent tensile strength and water resistance.

[0008] Preferably, in S1, the method for preparing biomass-based polyols from banana peels comprises: mixing 50-100g of banana peel powder, 30-100g of polyethylene glycol 400, 15-30g of ethylene glycol, and 1-3g of concentrated sulfuric acid; heating the mixture at 70-200°C under a nitrogen atmosphere for 3-10 hours; diluting the mixture with a 1,4-dioxane / water mixture at a mass ratio of 1:4-8; and subjecting the mixture to rotary evaporation to obtain the biomass-based polyols. The nitrogen atmosphere prevents oxidation of the raw materials at high temperatures, thereby improving liquefaction efficiency and product quality. The addition of polyethylene glycol 400 and ethylene glycol promotes the degradation of cellulose, hemicellulose, and lignin in the banana peels, thereby increasing the liquefaction rate. The concentrated sulfuric acid is a 98% by mass aqueous solution of sulfuric acid.

[0009] Preferably, in S2, 1g-15g of a biomass-based polyol, 30g-59g of a polyether polyol, 10g-60g of an isocyanate, 1g-10g of a hydroxy silicone oil, 1g-5g of 1,4-butanediol, and 0.1g-1g of dibutyltin dilaurate are mixed and stirred continuously at 70-120°C for 20-100 minutes to obtain a mixed raw material. The amount of hydroxy silicone oil added significantly affects the waterproofing and mechanical properties of the final product, while dibutyltin dilaurate, as a catalyst, promotes the reaction between the isocyanate and the hydroxyl group, improving the reaction efficiency.

[0010] Preferably, in S3, a mixture of 1g-10g of 2,2-dihydroxymethylpropionic acid and 5g-20g of N,N-dimethylformamide is added dropwise to the mixed raw material obtained in S2, and the mixture is stirred continuously at 40-120°C for 1-5h. Then, 1-5g of triethylamine is added dropwise. Heating is stopped, and 0.5g-4g of ethylenediamine and 100g-500g of ice water are quickly added dropwise while stirring to obtain a waterborne polyurethane. The addition of 2,2-dihydroxymethylpropionic acid introduces hydrophilic carboxyl groups, and triethylamine neutralizes the carboxyl groups to form a salt structure to enhance water dispersibility. The addition of ethylenediamine can extend the molecular chain and improve the mechanical properties of the polyurethane.

[0011] Preferably, the polyether polyol is polybutylene glycol; and the isocyanate is selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and mixtures thereof.

[0012] Preferably, the hydroxyl silicone oil has a hydroxyl value of 30 to 150 mgKOH / g and a viscosity of 10 to 5000 mPa·s. This preferred embodiment defines the key physical and chemical properties of the hydroxyl silicone oil. The hydroxyl value affects the degree of crosslinking between the silicone oil and the polyurethane, while determining the viscosity range helps control processing rheology and final product performance.

[0013] Preferably, the method comprises the following steps: S1: mixing 90g of banana peel powder, 80g of polyethylene glycol 400, 25g of ethylene glycol, and 2g of concentrated sulfuric acid, heating the mixture at 160°C under a nitrogen atmosphere for 7h; diluting the mixture with a 1:7 mass ratio of 1,4-dioxane to water, and subjecting the mixture to rotary evaporation to obtain a biomass-based polyol. S2: mixing 12g of the biomass-based polyol, 48g of polybutylene glycol, 50g of isocyanate, 8g of hydroxy silicone oil, 4g of 1,4-butanediol, and 0.8g of dibutyltin dilaurate, stirring the mixture continuously at 90°C for 60 min to obtain a mixed raw material. S3: adding a mixture of 8g of 2,2-dihydroxymethylpropionic acid and 10g of N,N-dimethylformamide dropwise to the solution, stirring the mixture continuously at 85°C for 3h, and then adding 3g of triethylamine dropwise. Finally, the heating was stopped, and 2 g of ethylenediamine and 300 g of ice water were rapidly added dropwise under high-speed stirring to obtain waterborne polyurethane.

[0014] A silicone-modified biomass-based waterborne polyurethane prepared by the method has a water contact angle of 40 to 110° and a tensile strength of 6 to 45 MPa. Preferably, the silicone-modified biomass-based waterborne polyurethane has a water contact angle of 102.56° and a tensile strength of 42.75 MPa.

[0015] A use of the organosilicon-modified biomass-based waterborne polyurethane in textile coatings, leather finishing, wood coatings, waterproof materials or high-strength membranes.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The present invention discloses a method for modifying biomass-based waterborne polyurethane using organosilicon, which increases the bio-based content and degradability of the product by introducing waste banana peel liquefaction products as biomass-based polyols, thus conforming to the development trend of green environmental protection.

[0018] The present invention uses hydroxy silicone oil to modify biomass-based waterborne polyurethane to form an organic-inorganic hybrid structure, significantly improving the tensile strength and water resistance of the product. Experimental results show that the waterborne polyurethane prepared under optimal conditions can reach a water contact angle of 102.56° and a tensile strength of 42.75 MPa.

[0019] The process of the present invention is simple, easy to operate, the reaction conditions in each step are mild, the raw materials are readily available, and it is suitable for industrial production;

[0020] The organosilicon-modified biomass-based waterborne polyurethane prepared by the present invention has both high strength and good waterproofness, and can be widely used in the fields of textile coating, leather finishing, wood coating, waterproof material or high-strength membrane material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the tensile strength of the waterborne polyurethanes obtained in Examples 1-6 (corresponding to samples 1-6);

[0022] Figure 2 is the elongation at break of the waterborne polyurethanes obtained in Examples 1-6 (corresponding to samples 1-6);

[0023] Figure 3 is the water contact angle of the waterborne polyurethane obtained in Examples 1-6 (corresponding to samples 1-6). DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described in detail below through specific examples. It should be understood that the implementation of the present invention is not limited to the following examples, and any form of modification and / or change made to the present invention will fall within the scope of protection of the present invention.

[0025] In the present invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. The methods in the following examples are all conventional methods in the art unless otherwise specified.

[0026] Unless otherwise specified, the reagents used in the following examples can be purchased from conventional biochemical reagent stores.

[0027] Example 1

[0028] A method for modifying biomass-based waterborne polyurethane using organosilicon, comprising the following steps:

[0029] (1) Mix 50 g of banana peel powder, 30 g of polyethylene glycol 400, 15 g of ethylene glycol, and 1 g of concentrated sulfuric acid (98% by mass sulfuric acid in water, the same below) and heat at 70°C for 3 h under a nitrogen atmosphere. Dilute the product with a 1:4 mass ratio of 1,4-dioxane to water and rotary evaporate to obtain a biomass-based polyol.

[0030] (2) 1 g of biomass-based polyol, 59 g of polybutylene glycol, 10 g of isocyanate, 1 g of hydroxy silicone oil, 1 g of 1,4-butanediol, and 0.1 g of dibutyltin dilaurate were mixed and stirred continuously at 70 °C for 20 min to obtain a mixed raw material.

[0031] (3) A mixture of 1 g of 2,2-dihydroxymethylpropionic acid and 5 g of N,N-dimethylformamide was added dropwise to the above solution, stirred continuously at 40°C for 1 h, and then 1 g of triethylamine was added dropwise. Finally, heating was stopped, and 0.5 g of ethylenediamine and 100 g of ice water were quickly added dropwise under high-speed stirring to obtain a waterborne polyurethane.

[0032] The waterborne polyurethane prepared according to this example had a water contact angle of 42.86° and a tensile strength of 6.9 MPa.

[0033] Example 2

[0034] A method for modifying biomass-based waterborne polyurethane using organosilicon, comprising the following steps:

[0035] (1) 60 g of banana peel powder, 40 g of polyethylene glycol 400, 20 g of ethylene glycol, and 1.5 g of concentrated sulfuric acid were mixed and heated at 100 °C for 4 h under a nitrogen atmosphere. The product was diluted with a 1:4 mass ratio of 1,4-dioxane / water mixture and subjected to rotary evaporation to obtain biomass-based polyols.

[0036] (2) 5 g of biomass-based polyol, 55 g of polybutylene glycol, 20 g of isocyanate, 2 g of hydroxy silicone oil, 2 g of 1,4-butanediol, and 0.3 g of dibutyltin dilaurate were mixed and stirred continuously at 80 °C for 40 min to obtain a mixed raw material.

[0037] (3) A mixture of 2 g of 2,2-dihydroxymethylpropionic acid and 10 g of N,N-dimethylformamide was added dropwise to the above solution, stirred continuously at 60°C for 2 h, and then 2 g of triethylamine was added dropwise. Finally, heating was stopped, and 1 g of ethylenediamine and 200 g of ice water were quickly added dropwise under high-speed stirring to obtain a waterborne polyurethane.

[0038] The waterborne polyurethane prepared according to this example had a water contact angle of 52.96° and a tensile strength of 11.55 MPa.

[0039] Example 3

[0040] A method for modifying biomass-based waterborne polyurethane using organosilicon, comprising the following steps:

[0041] (1) Mix 70 g of banana peel powder, 50 g of polyethylene glycol 400, 20 g of ethylene glycol, and 1.5 g of concentrated sulfuric acid and heat at 120°C for 6 h under a nitrogen atmosphere. Dilute the mixture with a 1:5 mass ratio of 1,4-dioxane to water and rotary evaporate to obtain a biomass-based polyol.

[0042] (2) 10 g of biomass-based polyol, 50 g of polybutylene glycol, 30 g of isocyanate, 4 g of hydroxy silicone oil, 3 g of 1,4-butanediol, and 0.5 g of dibutyltin dilaurate were mixed and stirred continuously at 90 °C for 60 min to obtain a mixed raw material.

[0043] (3) A mixture of 4 g of 2,2-dihydroxymethylpropionic acid and 10 g of N,N-dimethylformamide was added dropwise to the above solution, stirred continuously at 80°C for 3 h, and then 2 g of triethylamine was added dropwise. Finally, heating was stopped, and 2 g of ethylenediamine and 300 g of ice water were quickly added dropwise under high-speed stirring to obtain a waterborne polyurethane.

[0044] The waterborne polyurethane prepared according to this example had a water contact angle of 66.78° and a tensile strength of 22.43 MPa.

[0045] Example 4

[0046] A method for modifying biomass-based waterborne polyurethane using organosilicon, comprising the following steps:

[0047] (1) 80 g of banana peel powder, 60 g of polyethylene glycol 400, 25 g of ethylene glycol, and 2 g of concentrated sulfuric acid were mixed and heated at 140 °C for 6 h under a nitrogen atmosphere. The product was diluted with a mixture of 1,4-dioxane and water at a mass ratio of 1:6 and subjected to rotary evaporation to obtain biomass-based polyols.

[0048] (2) 12 g of biomass-based polyol, 48 g of polybutylene glycol, 40 g of isocyanate, 6 g of hydroxy silicone oil, 3 g of 1,4-butanediol, and 0.6 g of dibutyltin dilaurate were mixed and stirred continuously at 100 °C for 80 min to obtain a mixed raw material.

[0049] (3) A mixture of 7 g of 2,2-dihydroxymethylpropionic acid and 15 g of N,N-dimethylformamide was added dropwise to the above solution, and the mixture was stirred continuously at 100°C for 4 h. Then, 4 g of triethylamine was added dropwise. Finally, heating was stopped, and 3 g of ethylenediamine and 400 g of ice water were quickly added dropwise under high-speed stirring to obtain a waterborne polyurethane.

[0050] The waterborne polyurethane prepared according to this example had a water contact angle of 77.78° and a tensile strength of 26.78 MPa.

[0051] Example 5

[0052] A method for modifying biomass-based waterborne polyurethane using organosilicon, comprising the following steps:

[0053] (1) Mix 90 g of banana peel powder, 80 g of polyethylene glycol 400, 25 g of ethylene glycol, and 2 g of concentrated sulfuric acid and heat at 160°C for 7 h under a nitrogen atmosphere. Dilute the mixture with a 1:7 mass ratio of 1,4-dioxane to water and rotary evaporate to obtain a biomass-based polyol.

[0054] (2) 12 g of biomass-based polyol, 48 g of polybutylene glycol, 50 g of isocyanate, 8 g of hydroxy silicone oil, 4 g of 1,4-butanediol, and 0.8 g of dibutyltin dilaurate were mixed and stirred continuously at 90 °C for 60 min to obtain a mixed raw material.

[0055] (3) A mixture of 8 g of 2,2-dihydroxymethylpropionic acid and 10 g of N,N-dimethylformamide was added dropwise to the above solution, stirred continuously at 85°C for 3 h, and then 3 g of triethylamine was added dropwise. Finally, heating was stopped, and 2 g of ethylenediamine and 300 g of ice water were quickly added dropwise under high-speed stirring to obtain a waterborne polyurethane.

[0056] The waterborne polyurethane prepared according to this example had a water contact angle of 102.56° and a tensile strength of 42.75 MPa.

[0057] Example 6

[0058] A method for modifying biomass-based waterborne polyurethane using organosilicon, comprising the following steps:

[0059] (1) 100 g of banana peel powder, 100 g of polyethylene glycol 400, 30 g of ethylene glycol, and 3 g of concentrated sulfuric acid were mixed and heated at 200°C for 10 h under a nitrogen atmosphere. The product was diluted with a 1,4-dioxane / water mixture with a mass ratio of 1:8 and subjected to rotary evaporation to obtain biomass-based polyols.

[0060] (2) 15 g of biomass-based polyol, 45 g of polybutylene glycol, 60 g of isocyanate, 10 g of hydroxy silicone oil, 5 g of 1,4-butanediol, and 1 g of dibutyltin dilaurate were mixed and stirred continuously at 120 °C for 100 min to obtain a mixed raw material.

[0061] (3) A mixture of 10 g of 2,2-dihydroxymethylpropionic acid and 20 g of N,N-dimethylformamide was added dropwise to the above solution, and the mixture was stirred continuously at 120°C for 5 h. Then, 5 g of triethylamine was added dropwise. Finally, heating was stopped, and 4 g of ethylenediamine and 500 g of ice water were quickly added dropwise under high-speed stirring to obtain a waterborne polyurethane.

[0062] The waterborne polyurethane prepared according to this example had a water contact angle of 78.36° and a tensile strength of 31.20 MPa.

[0063] The tensile strength, elongation at break and water contact angle test data of the waterborne polyurethanes obtained in Examples 1-6 (corresponding to samples 1-6) are shown in Figure 1 、 Figure 2 and Figure 3 The results show that the product produced by the method of Example 5 has the best performance. The sample prepared has the highest tensile strength (42.8 MPa) and a good elongation at break (182.0%), indicating that this sample has good mechanical properties. In addition, this sample has the highest water contact angle (102.6°), indicating that this sample has good water resistance.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the methods.

[0065] The above describes in detail the method for modifying biomass-based waterborne polyurethane using organosilicon, as provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the method and core concepts of the present invention. It should be noted that those skilled in the art may make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A method for modifying biomass-based waterborne polyurethane using organosilicon, characterized in that The method includes the following steps: S1, liquefying banana peels to obtain biomass-based polyols; S2, uniformly mixing the obtained biomass-based polyols with polyether polyols, isocyanates, hydroxy silicone oils, 1,4-butanediol, and dibutyltin dilaurate to obtain a mixed raw material; S3, using the mixed raw material obtained in S2, as well as N,N-dimethylformamide, 2,2-dihydroxymethylpropionic acid, triethylamine, ethylenediamine, and distilled water as raw materials to prepare water-based polyurethane.

2. The method according to claim 1, wherein: In S1, the method for preparing biomass-based polyols using banana peels is as follows: 50-100 g of banana peel powder, 30 g-100 g of polyethylene glycol 400, 15 g-30 g of ethylene glycol, and 1-3 g of concentrated sulfuric acid are mixed, and the mixture is heated at 70-200° C. under a nitrogen atmosphere for 3-10 hours; the above product is diluted with a mixture of 1,4-dioxane / water with a mass ratio of 1:4-8, and the mixture is rotary evaporated to obtain a biomass-based polyol.

3. The method according to claim 1, wherein: In S2, 1 g to 15 g of biomass-based polyol, 30 g to 59 g of polyether polyol, 10 g to 60 g of isocyanate, 1 g to 10 g of hydroxy silicone oil, 1 g to 5 g of 1,4-butanediol, and 0.1 g to 1 g of dibutyltin dilaurate are mixed and continuously stirred at 70 to 120° C. for 20 to 100 min to obtain a mixed raw material.

4. The method according to claim 1, wherein: In S3, a mixture of 1 g to 10 g of 2,2-dihydroxymethylpropionic acid and 5 g to 20 g of N,N-dimethylformamide is added dropwise to the mixed raw material obtained in S2, and the mixture is continuously stirred at 40 to 120° C. for 1 to 5 hours. Then, 1 to 5 g of triethylamine is added dropwise. Heating is stopped, and 0.5 g to 4 g of ethylenediamine and 100 g to 500 g of ice water are quickly added dropwise while stirring to obtain a waterborne polyurethane.

5. The method according to claim 1, wherein: The polyether polyol is polybutylene glycol; the isocyanate is selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate and mixtures thereof.

6. The method according to claim 1, wherein: The hydroxyl silicone oil has a hydroxyl value of 30 to 150 mgKOH / g and a viscosity of 10 to 5000 mPa·s.

7. An organosilicon-modified biomass-based waterborne polyurethane prepared by the method according to any one of claims 1 to 6, having a water contact angle of 40 to 110° and a tensile strength of 6 to 45 MPa.

8. Use of the organosilicon-modified biomass-based waterborne polyurethane according to claim 7 in textile coatings, leather finishing, wood coatings, waterproof materials or high-strength membranes.

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