Solvent-free two-component polyurethane adhesive

Abstract

The invention relates to the technical field of adhesives, in particular to a solvent-free two-component polyurethane adhesive which is composed of a component A and a component B, the component A is prepared from the following raw materials: microalgae grease, hydrogen peroxide, formic acid, a nickel-based catalyst, bio-based furan diamine, a bio-based maleimide derivative, dimethyl carbonate, an ionic liquid catalyst, vanillin, lipase and furfuryl alcohol; the raw materials of the group B comprise nano cellulose, vanillin, polyethyleneimine, a bio-based material, potassium carbonate, a self-repairing agent and an antibacterial agent. The preparation method of the adhesive comprises the following steps: S1, preparing microalgae oil-based polyol; s2, preparing dynamic crosslinking type isocyanate; s3, synthesizing a dynamic prepolymer of the component A; s4, modifying the nano cellulose; s5, the bio-based HDI and vanillin are mixed and then react at 60 DEG C, potassium carbonate is added for catalysis, and the closed curing agent is obtained; and S6, preparing a component B curing agent. The problems that the main raw materials of the double-component polyurethane adhesive are non-renewable and are not beneficial to environmental protection during application are well solved.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, specifically a solvent-free two-component polyurethane adhesive. Background Art

[0002] The two-component polyurethane adhesive is an adhesive composed of a methyl component (main agent) and an ethyl component (curing agent). Due to its advantages such as adjustable performance, high bonding strength, and wide bonding range, it has become one of the polyurethane adhesives with the largest variety and output.

[0003] Currently, among the main raw materials for preparing two-component polyurethane, polyols and isocyanates are compounds produced from petroleum and coal. With the continuous improvement of the requirements for resource conservation and environmental protection, the development of polyurethane based on renewable resources is an inevitable trend in the polymer industry.

[0004] In addition, the preparation of two-component polyurethane adhesives usually requires the addition of a large amount of chemical solvents, which is not conducive to environmental protection and needs to be improved.

[0005] Therefore, there is an urgent need for a two-component polyurethane adhesive based on renewable resources as the main raw material and with environmental friendliness to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a solvent-free two-component polyurethane adhesive to solve the problems that the main raw materials of the current two-component polyurethane adhesive are non-renewable and not environmentally friendly during application.

[0007] To achieve the above purpose, the present invention provides the following technical solution: a solvent-free two-component polyurethane adhesive, which is composed of component A and component B;

[0008] Component A is prepared from the following raw materials by mass percentage: 68-75% of microalgae oil, 3-4% of hydrogen peroxide, 1-2% of formic acid, 0.5-1.2% of nickel-based catalyst, 10-15% of bio-based furan diamine, 7-10% of bio-based maleimide derivative, 2-3% of dimethyl carbonate, 0.3-1.0% of ionic liquid catalyst, 0.6-1.5% of vanillin, 0.08-0.15% of lipase, 0.8-1.2% of furfuryl alcohol;

[0009] Component B is prepared from the following raw materials by mass percentage: 65-75% of nanocellulose, 0.8-1.2% of vanillin, 3-5% of polyethyleneimine, 18-26% of bio-based HDI, 1.2-1.5% of potassium carbonate, 2-3% of self-healing agent, 1-2% of antibacterial agent. Among them, vanillin is a lignin derivative, the self-healing agent is a bio-based polythiol rubber containing dynamic disulfide bonds derived from allicin. The antibacterial agent is a chitosan-silver nanoparticle composite.

[0010] The preparation method of the adhesive comprises the following steps:

[0011] S1. Prepare microalgae oil-based polyol;

[0012] Use microalgae oil, hydrogen peroxide, formic acid, and nickel-based catalyst as raw materials to prepare microalgae oil polyol;

[0013] S2. Prepare dynamic cross-linked isocyanate;

[0014] Use bio-based furan diamine, bio-based maleimide derivative, dimethyl carbonate, ionic liquid catalyst, and vanillin as raw materials to prepare dynamic cross-linked isocyanate;

[0015] S3. Synthesis of A-component dynamic prepolymer;

[0016] First, purify the microalgae oil-based polyol;

[0017] Secondly, add the purified microalgae oil-based polyol, dynamic cross-linked isocyanate, and lipase into a microwave reactor for reaction to obtain a polymer;

[0018] Among them, the environmental conditions for the reaction in the microwave reactor are 50 °C, 300 W pulsed microwave radiation, NCO / OH = 2.0:1, and the reaction time is 25 minutes.

[0019] Thirdly, add furfuryl alcohol to the polymer to form a dynamic cross-linked network;

[0020] Finally, remove trace bubbles through supercritical CO 2 foaming-defoaming technology;

[0021] Among them, the process parameters of the supercritical CO 2 foaming-defoaming technology are a pressure of 8 MPa and a temperature of 40 °C;

[0022] S4. Modify nanocellulose;

[0023] Pass the nanocellulose dispersion liquid into a low-temperature plasma reactor to initiate the generation of free radicals on the surface, and then graft-polymerize with polyethyleneimine monomers to generate a polymer;

[0024] S5. Mix bio-based HDI and vanillin and react at 60 °C, and add potassium carbonate as a catalyst to obtain a blocked curing agent;

[0025] S6. Prepare B-component curing agent;

[0026] Mix the polymer, blocked curing agent, self-healing agent, and antibacterial agent in a blender to obtain the B-component curing agent.

[0027] Preferably, the preparation method of the microalgae oil-based polyol in step S1 is as follows:

[0028] S1.1, perform pretreatment of degumming and deacidification on microalgae oil;

[0029] After the microalgae oil is degummed with phosphoric acid, add NaOH solution to neutralize free fatty acids, and then centrifuge to separate impurities;

[0030] S1.2. Add the pretreated microalgae oil, formic acid, and hydrogen peroxide into a reaction kettle, and stir and react at 50 - 60 °C for 4 - 6 h to complete the epoxidation reaction;

[0031] S1.3. After washing the epoxidized microalgae oil to neutral, perform reduced pressure distillation to remove unreacted reagents;

[0032] S1.4. Pretreat the nickel-based catalyst by pre-reducing it in a hydrogen atmosphere for 2 h to activate the nickel-based catalyst;

[0033] S1.5. After mixing the treated epoxidized microalgae oil with the activated nickel-based catalyst, react at 160 - 180 °C and a hydrogen pressure of 0.6 - 0.8 MPa for 3 - 5 h to complete the hydrogenation ring-opening of the microalgae oil;

[0034] S1.6. Use the magnetic separation and recovery method to remove the nickel-based catalyst from the microalgae oil after hydrogenation ring-opening;

[0035] S1.7. Use the short-path molecular distillation method to remove low-molecular by-products to obtain the microalgae oil-based polyol.

[0036] Preferably, the preparation method of the dynamic cross-linking type isocyanate in step S2 is as follows:

[0037] S2.1. React bio-based furan diamine with dimethyl carbonate under the catalysis of an ionic liquid catalyst;

[0038] Among them, the reaction temperature is 80 °C and the reaction time is 5 h;

[0039] S2.2. Introduce CO gas with a pressure of 0.6 MPa to generate an intermediate carbamate; 2

[0040] S2.3. Pyrolyze the carbamate under vacuum conditions at 120 °C to release CO to obtain bio-based furan diisocyanate; 2

[0041] S2.4. Mix the bio-based furan diisocyanate with the bio-based maleimide derivative in a molar ratio of 1:0.8;

[0042] S2.5. Perform UV irradiation on the mixture of bio-based furan diisocyanate and bio-based maleimide derivative to form a dynamic network precursor;

[0043] S2.6. Add vanillin to the formed dynamic network precursor to obtain a dynamically crosslinked isocyanate.

[0044] Preferably, the inside of the plasma reactor used in step S4 is in an argon atmosphere and the power is 100 W.

[0045] Preferably, during the degumming of microalgae oil with phosphoric acid in step S1.1, the temperature is 60 °C and the stirring time is 1 h, and a 1% concentration of NaOH solution is used for deacidification.

[0046] Preferably, the microalgae oil in component A is selected from microalgae varieties with an oil content higher than 60%;

[0047] Among them, the microalgae oil is extracted from microalgae by supercritical CO 2 extraction method.

[0048] Preferably, when performing UV irradiation on the mixture of bio-based furan diisocyanate and bio-based maleimide derivative in step S2.5, ultraviolet light with a wavelength of 365 nm and a power of 50 W is used for irradiation.

[0049] Preferably, the vacuum degree in the blender in step S6 is -0.08 MPa.

[0050] Preferably, component A and component B are mixed and applied in a volume ratio of 1:1.

[0051] Compared with the prior art, the beneficial effects of the present invention are:

[0052] 1. The solvent-free two-component polyurethane adhesive involved in the present invention uses raw materials with a large bio-based content, and uses a microalgae oil + cellulose double carbon sink system to achieve a significant reduction in carbon emissions.

[0053] 2. The preparation process of the solvent-free two-component polyurethane adhesive involved in the present invention adopts a microwave + plasma process to achieve energy saving; the whole process has zero solvent emissions, and the COD of wastewater is greatly reduced, realizing environmental friendliness.

[0054] 3. The solvent-free two-component polyurethane adhesive involved in the present invention is easy to dissociate in an alkaline solution after being discarded, improving the raw material recovery rate; a large amount of bio-based raw materials are used, reducing the application of non-renewable raw materials, and achieving the purpose of saving resources. Specific embodiments

[0055] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0056] Example: A solvent-free two-component polyurethane adhesive, which is composed of component A and component B;

[0057] Component A is prepared from the following raw materials by mass percentage: 68-75% of microalgae oil, 3-4% of hydrogen peroxide, 1-2% of formic acid, 0.5-1.2% of nickel-based catalyst, 10-15% of bio-based furan diamine, 7-10% of bio-based maleimide derivative, 2-3% of dimethyl carbonate, 0.3-1.0% of ionic liquid catalyst, 0.6-1.5% of vanillin, 0.08-0.15% of lipase, 0.8-1.2% of furfuryl alcohol;

[0058] Component B is prepared from the following raw materials by mass percentage: 65-75% of nanocellulose, 0.8-1.2% of vanillin, 3-5% of polyethyleneimine, 18-26% of bio-based HDI, 1.2-1.5% of potassium carbonate, 2-3% of self-healing agent, 1-2% of antibacterial agent.

[0059] Among them, the microalgae oil in component A is selected from microalgae varieties with an oil content higher than 60%; and the microalgae oil is extracted from microalgae by supercritical CO 2 extraction method.

[0060] The preparation method of the adhesive includes the following steps:

[0061] S1. Prepare microalgae oil-based polyol;

[0062] Use microalgae oil, hydrogen peroxide, formic acid, and nickel-based catalyst as raw materials to prepare microalgae oil polyol;

[0063] Among them, the preparation method steps of microalgae oil-based polyol are:

[0064] S1.1. Perform pretreatment of degumming and deacidification on microalgae oil;

[0065] After the microalgae oil is degummed with phosphoric acid, add NaOH solution to neutralize free fatty acids, and then centrifuge to separate impurities; among them, the temperature during the phosphoric acid degumming of microalgae oil is 60°C and the stirring time is 1 h, and a 1% concentration of NaOH solution is used for deacidification.

[0066] S1.2. Add the pretreated microalgae oil, formic acid, and hydrogen peroxide into the reaction kettle together, and stir and react at 50-60°C for 4-6 h to complete the epoxidation reaction;

[0067] S1.3. After washing the epoxidized microalgae oil to neutral, carry out vacuum distillation to remove unreacted reagents.

[0068] S1.4. Pre - reduce the nickel - based catalyst in a hydrogen atmosphere for 2 h to activate the nickel - based catalyst.

[0069] S1.5. After mixing the treated epoxidized microalgae oil with the activated nickel - based catalyst, react at 160 - 180 °C and a hydrogen pressure of 0.6 - 0.8 MPa for 3 - 5 h to complete the hydrogenation ring - opening of the microalgae oil.

[0070] S1.6. Use magnetic separation recovery method to remove the nickel - based catalyst from the microalgae oil after hydrogenation ring - opening.

[0071] S1.7. Use short - path molecular distillation method to remove low - molecular - weight by - products to obtain microalgae - oil - based polyols.

[0072] S2. Prepare dynamic cross - linked isocyanate.

[0073] Use bio - based furan diamine, bio - based maleimide derivative, dimethyl carbonate, ionic liquid catalyst, and vanillin as raw materials to prepare dynamic cross - linked isocyanate.

[0074] Among them, the preparation method steps of the dynamic cross - linked isocyanate are as follows:

[0075] S2.1. React bio - based furan diamine with dimethyl carbonate under the catalysis of an ionic liquid catalyst.

[0076] Among them, the reaction temperature is 80 °C and the reaction time is 5 h.

[0077] S2.2. Introduce CO 2 gas with a pressure of 0.6 MPa to generate an intermediate carbamate.

[0078] S2.3. Pyrolyze the carbamate under vacuum conditions at 120 °C to release CO 2 and obtain bio - based furan diisocyanate.

[0079] S2.4. Mix bio - based furan diisocyanate with bio - based maleimide derivative in a molar ratio of 1:0.8.

[0080] S2.5. Carry out UV irradiation on the mixture of bio - based furan diisocyanate and bio - based maleimide derivative to form a dynamic network precursor.

[0081] Among them, when carrying out UV irradiation on the mixture of bio - based furan diisocyanate and bio - based maleimide derivative, use ultraviolet light with a wavelength of 365 nm and a power of 50 W for irradiation.

[0082] S2.6. Add vanillin to the formed dynamic network precursor to obtain a dynamically crosslinked isocyanate. S3. Synthesis of the A-component dynamic prepolymer;

[0083] First, purify the microalgae oil-based polyol;

[0084] Secondly, add the purified microalgae oil-based polyol, the dynamically crosslinked isocyanate and lipase into a microwave reactor for reaction to obtain a polymer;

[0085] Thirdly, add furfuryl alcohol to the polymer to form a dynamic crosslinked network;

[0086] Finally, remove trace bubbles through supercritical CO 2 foaming-defoaming technology;

[0087] Among them, the process parameters of the supercritical CO 2 foaming-defoaming technology are a pressure of 8 MPa and a temperature of 40 °C;

[0088] S4. Modify the nanocellulose;

[0089] Pass the nanocellulose dispersion into a low-temperature plasma reactor to initiate the generation of free radicals on the surface, and then graft-polymerize with polyethyleneimine monomers to generate a polymer;

[0090] Among them, the inside of the plasma reactor used is an argon atmosphere and the power is 100 W.

[0091] S5. Mix the bio-based HDI and vanillin and react at 60 °C, and add potassium carbonate as a catalyst to obtain a blocked curing agent;

[0092] S6. Preparation of the B-component curing agent;

[0093] Mix the polymer, the blocked curing agent, the self-healing agent and the antibacterial agent in a blender to obtain the B-component curing agent. Among them, the vacuum degree inside the blender is -0.08 MPa.

[0094] The A component and the B component are mixed and applied according to a volume ratio of 1:1.

[0095] Test Example 1. On the basis of the preparation method of the embodiment, the A component is prepared from the following raw materials by mass percentage: 68% microalgae oil, 3% hydrogen peroxide, 2% formic acid, 1% nickel-based catalyst, 13% bio-based furanediamine, 8% bio-based maleimide derivative, 2% dimethyl carbonate, 0.8% ionic liquid catalyst, 1.32% vanillin, 0.08% lipase, 0.8% furfuryl alcohol;

[0096] Component B is prepared from the following raw materials by mass percentage: 65% nanocellulose, 1% vanillin, 4% polyethyleneimine, 24% bio-based HDI, 1.4% potassium carbonate, 3% self-healing agent, 1.6% antibacterial agent.

[0097] In Test Example 2, based on the preparation method of the Example, Component A is prepared from the following raw materials by mass percentage: 72% microalgae oil, 3.2% hydrogen peroxide, 1.3% formic acid, 0.6% nickel-based catalyst, 11% bio-based furan diamine, 7.2% bio-based maleimide derivative, 2.2% dimethyl carbonate, 0.4% ionic liquid catalyst, 0.8% vanillin, 0.1% lipase, 1.2% furfuryl alcohol;

[0098] Component B is prepared from the following raw materials by mass percentage: 70% nanocellulose, 1.1% vanillin, 4% polyethyleneimine, 20% bio-based HDI, 1.2% potassium carbonate, 2.2% self-healing agent, 1.5% antibacterial agent.

[0099] The adhesives prepared from the two components in Test Example 1 and Test Example 2 are subjected to performance tests. The test items include curing speed, tensile strength, self-healing efficiency, bio-based content, and closed-loop recovery rate. The test results are shown in Table 1.

[0100] Table 1

[0101]

[0102] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. Solvent-free two-component polyurethane adhesive, characterized in that: It is composed of component A and component B; Component A is prepared from the following raw materials by mass percentage: 68-75% of microalgae oil, 3-4% of hydrogen peroxide, 1-2% of formic acid, 0.5-1.2% of nickel-based catalyst, 10-15% of bio-based furan diamine, 7-10% of bio-based maleimide derivative, 2-3% of dimethyl carbonate, 0.3-1.0% of ionic liquid catalyst, 0.6-1.5% of vanillin, 0.08-0.15% of lipase, and 0.8-1.2% of furan methanol; Component B is prepared from the following raw materials by mass percentage: 65-75% nanocellulose, 0.8-1.2% vanillin, 3-5% polyethyleneimine, 18-26% bio-based HDI, 1.2-1.5% potassium carbonate, 2-3% self-healing agent, and 1-2% antibacterial agent.

2. The solvent-free two-component polyurethane adhesive according to claim 1, characterized in that: The preparation method of the adhesive comprises the following steps: S1, preparing microalgae oil-based polyols; Microalgae oil polyols are prepared by using microalgae oil, hydrogen peroxide, formic acid and nickel-based catalyst as raw materials; S2, preparing dynamically cross-linked isocyanate; Dynamically cross-linked isocyanate is prepared by using bio-based furan diamine, bio-based maleimide derivatives, dimethyl carbonate, ionic liquid catalyst and vanillin as raw materials; S3, A component dynamic prepolymer synthesis; First, the microalgae oil-based polyols were purified; Secondly, the purified microalgae oil-based polyol, dynamically cross-linked isocyanate and lipase are added into a microwave reactor for reaction to obtain a polymer; Thirdly, furanol is added to the polymer to form a dynamic cross-linking network; Finally, the trace bubbles are removed by supercritical CO2 foaming-defoaming technology; Among them, the process parameters of supercritical CO2 foaming-defoaming technology are pressure 8MPa and temperature 40℃; S4, modification of nanocellulose; The nanocellulose dispersion is introduced into a low-temperature plasma reactor to induce the generation of free radicals on the surface, which are then grafted and polymerized with polyethyleneimine monomers to generate polymers; S5, mixing bio-based HDI and vanillin, reacting at 60° C., and adding potassium carbonate as a catalyst to obtain a blocked curing agent; S6. Preparation of curing agent for component B; The polymer, the blocked curing agent, the self-healing agent and the antimicrobial agent are mixed in a blender to obtain a B-component curing agent.

3. The solvent-free two-component polyurethane adhesive according to claim 2, characterized in that: The steps of the preparation method of microalgae oil-based polyol in step S1 are as follows: S1.1, pretreatment of microalgae oil by degumming and deacidification; After the microalgae oil is degummed by phosphoric acid, NaOH solution is added to neutralize the free fatty acids, and then the impurities are separated by centrifugation; S1.2, adding the pretreated microalgae oil, formic acid and hydrogen peroxide into a reactor, stirring and reacting at 50-60°C for 4-6 hours to complete the epoxidation reaction; S1.3, washing the epoxidized microalgae oil with water until it is neutral, and then performing a process of vacuum distillation to remove unreacted reagents; S1.4, pre-reducing the nickel-based catalyst under a hydrogen atmosphere for 2 h to activate the nickel-based catalyst; S1.5, mixing the treated epoxidized microalgae oil with the activated nickel-based catalyst, and reacting at 160-180° C. and 0.6-0.8 MPa of hydrogen pressure for 3-5 hours to complete the hydrogenation ring-opening of the microalgae oil; S1.6, using magnetic separation recovery method to remove nickel-based catalyst from microalgae oil after hydrogenation ring opening; S1.

7. Use short-range molecular distillation to remove low molecular weight by-products to obtain microalgae oil-based polyols.

4. The solvent-free two-component polyurethane adhesive according to claim 2, characterized in that: The preparation method of the dynamically cross-linked isocyanate in step S2 comprises the following steps: S2.1, reacting bio-based furan diamine with dimethyl carbonate under the catalytic action of an ionic liquid catalyst; The reaction temperature is 80°C and the reaction time is 5h; S2.2, introducing CO2 gas at a pressure of 0.6 MPa to generate an intermediate carbamate; S2.3, thermally decomposing carbamate under vacuum conditions at 120°C to release CO2 to obtain bio-based furan diisocyanate; S2.4, mixing bio-based furan diisocyanate and bio-based maleimide derivative in a molar ratio of 1:0.8; S2.5, subjecting the mixture of bio-based furan diisocyanate and bio-based maleimide derivative to UV irradiation to form a dynamic network precursor; S2.

6. Add vanillin to the formed dynamic network precursor to obtain dynamic cross-linking isocyanate.

5. The solvent-free two-component polyurethane adhesive according to claim 2, characterized in that: The plasma reactor used in step S4 has an argon atmosphere and a power of 100W.

6. The solvent-free two-component polyurethane adhesive according to claim 3, characterized in that: In the step S1.1, the temperature during phosphoric acid degumming of the microalgae oil is 60° C. and the stirring time is 1 hour, and a 1% concentration NaOH solution is used for deacidification.

7. The solvent-free two-component polyurethane adhesive according to claim 1, characterized in that: The microalgae oil in the A component is selected from microalgae varieties with an oil content higher than 60%; Among them, microalgae oil is extracted from microalgae by critical CO2 extraction method.

8. The solvent-free two-component polyurethane adhesive according to claim 4, characterized in that: In the step S2.5, when the mixture of the bio-based furan diisocyanate and the bio-based maleimide derivative is subjected to UV irradiation, ultraviolet rays with a wavelength of 365 nm and a power of 50 W are used for irradiation.

9. The solvent-free two-component polyurethane adhesive according to claim 2, characterized in that: In step S6, the vacuum degree in the mixer is -0.08 MPa.

10. The solvent-free two-component polyurethane adhesive according to claim 1, characterized in that: Component A and component B are mixed in a volume ratio of 1:1.

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