A bio-based polyurethane resin, its preparation method and use

Abstract

The present application relates to a kind of bio-based polyurethane resin and its preparation method and application, the preparation raw material of the bio-based polyurethane resin includes: bio-based isocyanate compound 15-25 parts, bio-based polycarbonate polyol 60-80 parts, bio-based chain extender 2-20 parts and catalyst 0.01-0.5 parts;The bio-based content of the bio-based polyurethane resin is ≥90%.The bio-based polyurethane resin of environment-friendly is prepared by using specific proportion of bio-based raw material monomer, it has excellent mechanical property, light transmittance and yellowing resistance, greatly expands the application of polyurethane.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a bio-based polyurethane resin, its preparation method, and its application. Background Technology

[0002] Polyurethane, a polymer material with a variety of excellent properties, is widely used in green building, lightweight materials, energy conservation, and emission reduction due to its good physical and mechanical properties, easily tunable chemical structure, and good biocompatibility. In recent years, with the introduction of the "dual carbon" target, the green transformation of its raw materials has been continuously developed and practiced through the efforts of industry enterprises and technical experts. Bio-based polyurethane is one such direction.

[0003] Bio-based polyurethane materials are high-molecular polymers prepared from renewable resources, possessing excellent sustainability and environmental friendliness, thus attracting significant attention. In the automotive and transportation sectors, bio-based polyurethane is used as a lightweight material in the manufacture of automotive parts, body components, and interior trim to improve fuel efficiency and reduce overall vehicle weight. In the construction and home decoration sectors, bio-based polyurethane is used to manufacture insulation materials, sealants, and coatings to improve building energy efficiency and environmental friendliness. In the food packaging sector, bio-based polyurethane inks are used for printing on various food, pharmaceutical, and daily necessities packaging products, featuring high gloss, good resistance (such as temperature resistance, oil resistance, and resistance to weak acids and alkalis), environmental friendliness, and wide applicability. In the healthcare sector, bio-based polyurethane is used to manufacture medical devices, implants, and artificial organs, exhibiting biocompatibility and non-toxicity. With increasing global focus on sustainable development, the market demand for bio-based polyurethane, as a green material to replace traditional petrochemical polyurethane, is showing a year-on-year growth trend. Consumers' preference for environmentally friendly products and increasingly stringent government environmental regulations also provide development opportunities for the bio-based polyurethane market.

[0004] However, currently synthesized bio-based polyurethane products are inferior to traditionally obtained petroleum-based polyurethane materials in terms of strength and heat resistance, and their higher production costs hinder industrialization. Furthermore, when polyurethane is used in optical coatings, inks, or adhesives, it often requires both good light transmittance and resistance to yellowing, which existing bio-based polyurethane technologies struggle to meet. For example, CN113336664A discloses a bio-based waterborne polyurethane resin, its preparation method, and its applications. Using polyols, diisocyanates, polycarbodiimides, catalysts, neutralizing agents, and bio-based chain extenders with specific structures, the prepared waterborne resin exhibits excellent weather resistance and aging resistance, suitable for outdoor applications or those requiring high weather resistance. However, it does not address the material's optical properties and still suffers from insufficient mechanical properties, failing to meet application requirements in some high-mechanical-requirement scenarios.

[0005] Therefore, developing a bio-based polyurethane resin with excellent optical and mechanical properties that conforms to green and sustainable development has important application value. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a bio-based polyurethane resin, its preparation method, and its applications. The raw materials for preparing the bio-based polyurethane resin include bio-based isocyanate compounds, bio-based polycarbonate polyols, bio-based chain extenders, and catalysts. Using isocyanates, polycarbonate polyols, and bio-based chain extenders derived from biomass as raw materials, an environmentally friendly bio-based polyurethane resin material is obtained, exhibiting excellent mechanical strength, light transmittance, and resistance to yellowing, greatly expanding the applications of polyurethane.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a bio-based polyurethane resin, wherein the raw materials for preparing the bio-based polyurethane resin, by weight, include: 15-25 parts of bio-based isocyanate compound, 60-80 parts of bio-based polycarbonate polyol, 2-20 parts of bio-based chain extender and 0.01-0.5 parts of catalyst.

[0009] The bio-based polyurethane resin has a bio-based content of ≥90%.

[0010] The bio-based isocyanate compounds used in this invention are obtained from biological raw materials through bio-fermentation and further processing. They are combined with bio-based polycarbonate polyols to prepare bio-based polyurethane resin materials, which have excellent optical and mechanical properties, high bio-based content, and are environmentally friendly. By using a specific ratio of isocyanate monomers, polycarbonate polyol monomers, and bio-based chain extenders, the strength and flexibility of the obtained bio-based polyurethane resin are improved, while also giving it high light transmittance and resistance to yellowing, meeting the application needs of optical coatings, inks, and adhesives.

[0011] The bio-based isocyanate compound is 15-25 parts, for example, 16 parts, 18 parts, 20 parts, 22 parts or 24 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0012] The bio-based polycarbonate polyol is 60-80 parts, for example, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts or 78 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0013] The bio-based chain extender is 2-20 parts, for example, 4 parts, 6 parts, 8 parts, 10 parts, 12 parts, 15 parts or 18 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0014] The catalyst is 0.01-0.5 parts, for example, 0.02 parts, 0.05 parts, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts or 0.4 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0015] The "parts" and "parts by weight" used in this invention are calculated based on solid content and do not include solvents, dispersants, etc.

[0016] The bio-based polyurethane resin has a bio-based content of ≥90%, for example, it can be 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0017] Preferably, the raw materials for preparing the bio-based polyurethane resin, by weight, include: 18-23 parts of bio-based isocyanate compound (e.g., 19, 20, 21, or 22 parts, etc.), 64-74 parts of bio-based polycarbonate polyol (e.g., 65, 67, 69, 71, or 73 parts, etc.), 7-13 parts of bio-based chain extender (e.g., 8, 9, 10, 11, or 12 parts, etc.), and 0.01-0.1 parts of catalyst (e.g., 0.03, 0.04, 0.06, 0.08, or 0.09 parts, etc.).

[0018] Preferably, the molar ratio of isocyanate groups to hydroxyl groups in the bio-based isocyanate compound is (0.85-1.15):1, for example, it can be 0.9:1, 0.95:1, 1:1, 1.05:1 or 1.1:1, and specific values ​​between the above points are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0019] Preferably, the bio-based polyurethane resin has a weight-average molecular weight of 35,000-51,000 g / mol, for example, 36,000 g / mol, 38,000 g / mol, 40,000 g / mol, 42,000 g / mol, 45,000 g / mol, 48,000 g / mol or 50,000 g / mol, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0020] Preferably, the bio-based isocyanate compound has a bio-based content of 100%.

[0021] Preferably, the bio-based isocyanate compounds include bio-based aliphatic isocyanates and / or their trimers.

[0022] Preferably, the bio-based isocyanate compound includes 1,5-pentamethylene diisocyanate and / or its trimer.

[0023] Preferably, the raw material for preparing the 1,5-pentamethylene diisocyanate includes bio-based pentanediamine.

[0024] Preferably, the bio-based pentanediamine is obtained by bio-fermentation.

[0025] Preferably, the raw materials for preparing the bio-based pentanediamine include any one or a combination of at least two of corn, glucose, or lysine.

[0026] Preferably, the 1,5-pentamethylene diisocyanate is prepared by a non-phosgene method.

[0027] The bio-based 1,5-pentamethylene diisocyanate (PDI) monomer used in this invention is prepared from bio-raw materials through bio-fermentation and enzymatic decarboxylation to produce 1,5-pentanediamine, which is then obtained from 1,5-pentanediamine through non-phosgene methods such as carbonylation and pyrolysis. PDI has advantages such as fast curing speed, high flexibility, and good transparency. Its molecular structure is very similar to hexamethylene diisocyanate (HDI), but it has a higher carbon content and is 100% derived from biomass, possessing sustainable and circular advantages. By compounding bio-based PDI with bio-based polycarbonate polyols, the optical and mechanical properties of the resulting polyurethane material are further improved.

[0028] For example, the bio-fermentation includes the fermentation of sugarcane waste molasses to prepare L-lysine, and the enzymatic decarboxylation of L-lysine to prepare bio-based pentanediamine; the one-step fermentation method disclosed by Cathay Biotech to produce pentanediamine from corn as raw material; and the glucose fermentation to produce pentanediamine disclosed by the Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, etc.

[0029] The non-phosgene method described herein can be referenced in CN115350660A. The method conditions are mild and can effectively improve the yield of 1,5-pentanediisocyanate. The product contains extremely low levels of impurities such as hydrolyzed chlorine, which is beneficial for synthesizing high-performance polyurethane materials. The process does not involve highly toxic reagents and is green and environmentally friendly.

[0030] Preferably, the weight-average molecular weight of the bio-based polycarbonate polyol is 1000-3000 g / mol, for example, it can be 1100 g / mol, 1200 g / mol, 1300 g / mol, 1400 g / mol, 1500 g / mol, 1600 g / mol, 1700 g / mol, 1800 g / mol, 1900 g / mol, 2000 g / mol, 2100 g / mol, 2300 g / mol, 2500 g / mol, 2700 g / mol, 2900 g / mol or 3000 g / mol, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0031] Preferably, the bio-based polycarbonate polyol includes bio-based polycarbonate diol.

[0032] Preferably, the bio-based polycarbonate diol includes poly(isosorbate carbonate) diol, poly(1,4-butanediol carbonate) diol, poly(1,5-pentanediol carbonate) diol, poly(1,6-hexanediol carbonate) diol, and poly(limonene carbonate) diol.

[0033] Preferably, the bio-based polycarbonate polyol has a bio-based content of 70-93%, for example, it can be 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90% or 92%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0034] Preferably, the bio-based chain extender includes a bio-based alcohol chain extender.

[0035] Preferably, the bio-based alcohol chain extender includes any one or a combination of at least two of isosorbide, 1,4-butanediol, 1,5-pentanediol, or 1,6-hexanediol.

[0036] Preferably, the bio-based chain extender has a bio-based content of 74-99%, for example, it can be 75%, 78%, 80%, 82%, 85%, 88%, 90%, 92%, 95% or 98%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0037] Preferably, the catalyst comprises an organotin catalyst and / or an organobismuth catalyst.

[0038] Preferably, the organotin catalyst comprises any one or a combination of at least two of dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, methyl thiotin, or stannous octoate.

[0039] Preferably, the organic bismuth catalyst comprises any one or a combination of at least two of bismuth isooctanoate, bismuth neodecanoate, or bismuth tridecanoate.

[0040] The raw materials for preparing the bio-based polyurethane resin also include solvents. The amount of solvent added is selected by those skilled in the art based on experience and process requirements to facilitate preparation. In subsequent drying, semi-curing or complete curing stages, the solvent will partially or completely evaporate.

[0041] The solvent used in this invention is not particularly limited, and can generally be ketones such as acetone, butanone, and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; alcohols such as ethyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, carbitol, or butyl carbitol; and nitrogen-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, or N-methyl-2-pyrrolidone. The solvent can be used alone or in combination of two or more. Preferably, it is any one or a combination of at least two of N,N-dimethylformamide, N,N-dimethylacetamide, or N-methyl-2-pyrrolidone.

[0042] In a second aspect, the present invention provides a method for preparing the bio-based polyurethane resin as described in the first aspect, the method comprising the following steps:

[0043] The bio-based isocyanate compound, bio-based polycarbonate polyol, bio-based chain extender, catalyst, and optional solvent are mixed and reacted to obtain the bio-based polyurethane resin.

[0044] Preferably, the preparation method includes the following steps:

[0045] (1) A mixture of bio-based isocyanate compounds, bio-based polycarbonate polyols and a catalyst was reacted to obtain a polyurethane prepolymer.

[0046] (2) The polyurethane prepolymer obtained in step (1) is mixed with a bio-based chain extender and a solvent and reacted. The solvent is evaporated to obtain the bio-based polyurethane resin.

[0047] Preferably, the step (1) includes preprocessing.

[0048] Preferably, the pretreatment includes vacuum dehydration of the bio-based polycarbonate polyol.

[0049] Preferably, step (1) is performed in the presence of a protective gas.

[0050] Preferably, the protective gas includes any one of nitrogen, argon, or helium.

[0051] Preferably, the reaction temperature in step (1) is 50-90°C, for example, it can be 55°C, 60°C, 65°C, 70°C, 75°C, 80°C or 85°C, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0052] Preferably, the reaction time in step (1) is 1.5-4 hours, for example, 2 hours, 2.5 hours, 3 hours or 3.5 hours, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0053] Preferably, step (2) is performed in the presence of a protective gas.

[0054] Preferably, the protective gas includes any one of nitrogen, argon, or helium.

[0055] Preferably, the reaction temperature in step (2) is 25-65°C, for example, it can be 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0056] Preferably, the reaction time in step (2) is 1-4 hours, for example, 1.5 hours, 2 hours, 2.5 hours, 3 hours or 3.5 hours, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0057] Preferably, the solvent includes N,N-dimethylformamide and / or N,N-dimethylacetamide.

[0058] Preferably, the preparation method includes the following steps:

[0059] (1) After dehydrating the bio-based polycarbonate polyol under vacuum, it is mixed with bio-based isocyanate compounds and catalyst, and reacted in a protective gas at 50-90℃ for 1.5-4h to obtain polyurethane prepolymer.

[0060] (2) The polyurethane prepolymer obtained in step (1) is mixed with a bio-based chain extender and a solvent, and reacted in a protective gas at 25-65°C for 1-4 hours. The solvent is then evaporated to obtain the bio-based polyurethane resin.

[0061] Thirdly, the present invention provides the application of the bio-based polyurethane resin as described in the first aspect in optical coatings, inks or adhesives.

[0062] Compared with the prior art, the present invention has at least the following beneficial effects:

[0063] This invention produces a bio-based polyurethane resin by using a specific ratio of bio-based isocyanate compounds, bio-based polycarbonate polyols, bio-based chain extenders, and catalysts. The material exhibits excellent strength, flexibility, and optical properties, with a tensile strength ≥27.1 MPa, elongation at break ≥516%, and light transmittance ≥88.5%. Simultaneously, it has a yellowing index ≤1.03, demonstrating excellent resistance to yellowing and meeting the application requirements in fields such as optical coatings, inks, and adhesives. Detailed Implementation

[0064] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0065] In the following specific embodiments of the present invention, the materials involved are as follows:

[0066] (1) Isocyanate compounds

[0067] Bio-based 1,5-pentamethylene diisocyanate, with a bio-based content of 100%, is prepared by the non-phosgene method in Example 1 of patent CN115350660A;

[0068] The non-bio-based 1,5-pentamethylene diisocyanate has a bio-based content of 0% and is prepared by the phosgene method in Example 3 of patent CN112457217A.

[0069] (2) Bio-based polycarbonate polyols

[0070] PCDL 1000, 93% bio-based, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0071] LNB-1216, 93% bio-based, Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0072] PCDL 3000, 93% bio-based, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0073] SYHT3500, 93% bio-based, Shanghai Shuyu Chemical Co., Ltd.

[0074] (3) Chain extender

[0075] Bio-based isosorbide, 94% bio-based content, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0076] Non-biological isosorbide, Jiangsu Bost Chemical Technology Co., Ltd.

[0077] Example 1

[0078] A bio-based polyurethane resin, said bio-based polyurethane resin being prepared by the following method:

[0079] 64.0g of polycarbonate polyol (PCDL 1000) was vacuum dehydrated for 3h and placed in a round-bottom flask. 18.5g of bio-based 1,5-pentamethylene diisocyanate (PDI, 100% bio-based) was added. The mixture was stirred mechanically at 70℃ for 2.5h to obtain a polyurethane prepolymer.

[0080] The temperature was lowered to 50°C, and 8.8g of bio-based isosorbide, 0.11g of dibutyltin dilaurate (DBTDL), and 10mL of N,N-dimethylformamide were added dropwise. The mixture was stirred for 3 hours to obtain a polyurethane resin emulsion. The obtained polyurethane resin emulsion was poured onto a polytetrafluoroethylene mold, cast into a film, and then placed in a vacuum drying oven. The temperature was raised to 80°C to evaporate the solvent, thus obtaining the bio-based polyurethane resin.

[0081] Example 2

[0082] A bio-based polyurethane resin, said bio-based polyurethane resin being prepared by the following method:

[0083] 74g of polycarbonate polyol (PCDL 3000) was vacuum dehydrated for 3 hours and placed in a round-bottom flask. 23.0g of bio-based 1,5-pentamethylene diisocyanate (PDI, 100% bio-based) was added. The mixture was stirred mechanically at 70℃ for 2.5 hours to obtain a polyurethane prepolymer.

[0084] The temperature was lowered to 50°C, and 13.0 g of bio-based isosorbide, 0.31 g of dibutyltin dilaurate (DBTDL), and 10 mL of N,N-dimethylformamide were added dropwise. The mixture was stirred for 3 h to obtain a polyurethane resin emulsion. The obtained polyurethane resin emulsion was poured onto a polytetrafluoroethylene mold, cast into a film, and then placed in a vacuum drying oven. The temperature was raised to 80°C to evaporate the solvent, thus obtaining the bio-based polyurethane resin.

[0085] Example 3

[0086] A bio-based polyurethane resin, wherein the bio-based polyurethane resin differs from that of Example 1 only in that the amount of bio-based 1,5-pentamethylene diisocyanate added is 15g, and all other aspects are the same as those of Example 1.

[0087] Example 4

[0088] A bio-based polyurethane resin, wherein the bio-based polyurethane resin differs from that of Example 1 only in that the amount of bio-based 1,5-pentamethylene diisocyanate added is 25g, and all other aspects are the same as those of Example 1.

[0089] Example 5

[0090] A bio-based polyurethane resin, wherein the only difference between the bio-based polyurethane resin and Example 1 is that the amount of bio-based isosorbide added is 15g, and all other aspects are the same as in Example 1.

[0091] Example 6

[0092] A bio-based polyurethane resin, wherein the bio-based polyurethane resin differs from that of Example 1 only in that the amount of bio-based isosorbide added is 2g, and all other aspects are the same as those of Example 1.

[0093] Example 7

[0094] A bio-based polyurethane resin, wherein the bio-based polyurethane resin differs from that of Example 1 only in that the bio-based 1,5-pentamethylene diisocyanate is replaced with 1,4-butanediisocyanate with the same bio-based content, and all other aspects are the same as those of Example 1.

[0095] Example 8

[0096] A bio-based polyurethane resin, wherein the only difference between the bio-based polyurethane resin and Example 1 is that the polycarbonate polyol (PCDL 1000) is replaced with a polycarbonate polyol (Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., lnb-1216) with the same bio-based content and a weight-average molecular weight of 700 g / mol, and all other aspects are the same as in Example 1.

[0097] Example 9

[0098] A bio-based polyurethane resin, wherein the bio-based polyurethane resin differs from that of Example 1 only in that the polycarbonate polyol (PCDL 1000) is replaced with a polycarbonate polyol (Shanghai Shuyu Chemical Co., Ltd., SYHT3500) with the same bio-based content and a weight-average molecular weight of 3500 g / mol, and all other aspects are the same as those of Example 1.

[0099] Comparative Example 1

[0100] A bio-based polyurethane resin, the only difference between the bio-based polyurethane resin and Example 1 is that the polycarbonate polyol (PCDL 1000) is replaced with polycaprolactone polyol (PCL 1000, Shanghai McLean Biochemical Technology Co., Ltd.) with the same bio-based content, and all other aspects are the same as Example 1.

[0101] Comparative Example 2

[0102] A bio-based polyurethane resin, wherein the bio-based polyurethane resin differs from that of Example 1 only in that the bio-based 1,5-pentamethylene diisocyanate with a bio-based content of 100% is replaced with a non-bio-based 1,5-pentamethylene diisocyanate with a bio-based content of 0%, and all other aspects are the same as those of Example 1.

[0103] Comparative Example 3

[0104] A bio-based polyurethane resin, the only difference between the bio-based polyurethane resin and Example 1 is that the polycarbonate polyol (PCDL 1000) is replaced with a non-bio-based polycarbonate polyol (Guangzhou Haoyi New Material Technology Co., Ltd., PCDL 1011), and all other aspects are the same as in Example 1.

[0105] Comparative Example 4

[0106] A bio-based polyurethane resin, wherein the bio-based polyurethane resin differs from that of Example 1 only in that the bio-based isosorbide is replaced with non-bio-based isosorbide, and all other aspects are the same as those of Example 1.

[0107] The above-mentioned bio-based polyurethane resin was subjected to the following tests:

[0108] (1) Tensile strength and elongation at break: Stress-strain curves were obtained by a universal testing machine, model: CMT4104.

[0109] (2) Transmittance: The transmittance was tested by a UV-Vis spectrophotometer. The spectral range of the above samples was 400-800 nm using an integrating sphere attachment.

[0110] (3) Yellowing Index (YI): Referring to GB / T16422.3, an aging test was conducted using an LED ultraviolet lamp with model ZX-UV06. The yellowing index was measured by a yellowness index meter with model LabScan-XE.

[0111] The test results are summarized in Table 1.

[0112] Table 1

[0113]

[0114]

[0115] The test results show that the present invention, by using a specific ratio of bio-based isocyanate compounds, bio-based polycarbonate polyols, bio-based chain extenders, and catalysts, produces a bio-based polyurethane resin. The material exhibits excellent strength, flexibility, and optical properties, with a tensile strength ≥27.1 MPa, elongation at break ≥516%, light transmittance ≥88.5%, and a yellowing index ≤1.03. In some preferred technical solutions, the tensile strength can reach 39.7 MPa, the elongation at break reaches 897%, the light transmittance is 93.2%, and the yellowing index is 0.75, which can meet the application requirements of optical coatings, inks, adhesives, and other fields.

[0116] By comparing Example 1 with Examples 3-9, it can be seen that the present invention, by further adjusting the proportion of each bio-based reactive monomer, the types of bio-based isocyanate compounds and the molecular weight of polycarbonate polyol, obtained a polyurethane resin material with excellent mechanical properties, light transmittance and yellowing resistance.

[0117] By comparing Example 1 and Comparative Example 1, it can be seen that the present invention improves the mechanical and optical properties of polyurethane by using polycarbonate polyols in combination with other bio-based components, resulting in a more superior overall application effect.

[0118] By comparing Example 1 with Comparative Examples 2-4, it can be seen that the present invention can obtain polyurethane materials with excellent mechanical properties, light transmittance and yellowing resistance by using bio-based isocyanate compounds, bio-based polycarbonate polyols and bio-based chain extenders. However, when bio-based raw materials are not used, the mechanical properties, light transmittance and yellowing resistance of the obtained polyurethane materials are significantly reduced.

[0119] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A bio-based polyurethane resin, characterized in that, The raw materials for preparing the bio-based polyurethane resin, by weight, include: 15-25 parts of bio-based isocyanate compound, 60-80 parts of bio-based polycarbonate polyol, 2-20 parts of bio-based chain extender, and 0.01-0.5 parts of catalyst. The bio-based isocyanate compounds include 1,5-pentamethylene diisocyanate and / or its trimer; The raw materials for preparing the 1,5-pentamethylene diisocyanate include bio-based pentanediamine; The bio-based pentanediamine is obtained through biological fermentation; The raw materials for preparing the bio-based pentanediamine include any one or a combination of at least two of corn, glucose, or lysine. The bio-based polycarbonate polyols include bio-based polycarbonate diols; The bio-based chain extender includes bio-based alcohol chain extenders; The bio-based alcohol chain extender includes any one or a combination of at least two of isosorbide, 1,4-butanediol, 1,5-pentanediol or 1,6-hexanediol; The catalyst includes organotin catalysts and / or organobismuth catalysts; The bio-based polyurethane resin has a bio-based content of ≥90%.

2. The bio-based polyurethane resin according to claim 1, characterized in that, The raw materials for preparing the bio-based polyurethane resin, by weight, include: 18-23 parts of bio-based isocyanate compound, 64-74 parts of bio-based polycarbonate polyol, 7-13 parts of bio-based chain extender, and 0.01-0.1 parts of catalyst.

3. The bio-based polyurethane resin according to claim 1, characterized in that, The molar ratio of isocyanate groups to hydroxyl groups in the bio-based isocyanate compounds is (0.85-1.15):

1.

4. The bio-based polyurethane resin according to claim 1, characterized in that, The bio-based polyurethane resin has a weight-average molecular weight of 35,000-51,000 g / mol.

5. The bio-based polyurethane resin according to any one of claims 1-3, characterized in that, The bio-based isocyanate compounds contain 100% bio-based components.

6. The bio-based polyurethane resin according to claim 1, characterized in that, The bio-based polycarbonate polyol has a weight-average molecular weight of 1000-3000 g / mol.

7. The bio-based polyurethane resin according to claim 1, characterized in that, The bio-based polycarbonate diols include poly(isosorbate carbonate) diol, poly(1,4-butanediol carbonate) diol, poly(1,5-pentanediol carbonate) diol, poly(1,6-hexanediol carbonate) diol, and poly(limonene carbonate) diol.

8. The bio-based polyurethane resin according to claim 6, characterized in that, The bio-based polycarbonate polyol has a bio-based content of 70-93%.

9. The bio-based polyurethane resin according to claim 1, characterized in that, The bio-based chain extender has a bio-based content of 74-99%.

10. The bio-based polyurethane resin according to claim 1, characterized in that, The organotin catalyst includes any one or a combination of at least two of dibutyltin dilaurate, dibutyltin diacetate, di-n-octyltin dilaurate, methyl thiotin, or stannous octoate.

11. The bio-based polyurethane resin according to claim 1, characterized in that, The organic bismuth catalyst includes any one or a combination of at least two of bismuth isooctanoate, bismuth neodecanoate, or bismuth tridecanoate.

12. A method for preparing a bio-based polyurethane resin as described in any one of claims 1-11, characterized in that, The preparation method includes the following steps: The bio-based isocyanate compound, bio-based polycarbonate polyol, bio-based chain extender, catalyst, and optional solvent are mixed and reacted to obtain the bio-based polyurethane resin.

13. The method for preparing the bio-based polyurethane resin according to claim 12, characterized in that, The preparation method includes the following steps: (1) A mixture of bio-based isocyanate compounds, bio-based polycarbonate polyols and a catalyst is reacted to obtain a polyurethane prepolymer; (2) The polyurethane prepolymer obtained in step (1) is mixed with a bio-based chain extender and a solvent and reacted. The solvent is evaporated to obtain the bio-based polyurethane resin.

14. The method for preparing the bio-based polyurethane resin according to claim 13, characterized in that, The process before step (1) includes preprocessing.

15. The method for preparing the bio-based polyurethane resin according to claim 14, characterized in that, The pretreatment includes vacuum dehydration of the bio-based polycarbonate polyol.

16. The method for preparing the bio-based polyurethane resin according to claim 13, characterized in that, Step (1) is performed in the presence of a protective gas.

17. The method for preparing the bio-based polyurethane resin according to claim 16, characterized in that, The protective gas includes any one of nitrogen, argon, or helium.

18. The method for preparing the bio-based polyurethane resin according to claim 13, characterized in that, The reaction temperature in step (1) is 50-90℃.

19. The method for preparing the bio-based polyurethane resin according to claim 13, characterized in that, The reaction time in step (1) is 1.5-4 h.

20. The method for preparing the bio-based polyurethane resin according to claim 13, characterized in that, Step (2) is performed in the presence of a protective gas.

21. The method for preparing the bio-based polyurethane resin according to claim 20, characterized in that, The protective gas includes any one of nitrogen, argon, or helium.

22. The method for preparing the bio-based polyurethane resin according to claim 13, characterized in that, The reaction temperature in step (2) is 25-65℃.

23. The method for preparing the bio-based polyurethane resin according to claim 13, characterized in that, The reaction time described in step (2) is 1-4 h.

24. The method for preparing the bio-based polyurethane resin according to claim 12 or 13, characterized in that, The solvent includes N,N-dimethylformamide and / or N,N-dimethylacetamide.

25. The method for preparing the bio-based polyurethane resin according to claim 12 or 13, characterized in that, The preparation method includes the following steps: (1) After dehydrating the bio-based polycarbonate polyol under vacuum, it is mixed with bio-based isocyanate compounds and catalyst, and reacted in a protective gas at 50-90℃ for 1.5-4 h to obtain polyurethane prepolymer; (2) The polyurethane prepolymer obtained in step (1) is mixed with a bio-based chain extender and a solvent, and reacted in a protective gas at 25-65°C for 1-4 h. The solvent is then evaporated to obtain the bio-based polyurethane resin.

26. The use of a bio-based polyurethane resin as described in any one of claims 1-11 in optical coatings, inks or adhesives.

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