Modified two-component polyurethane structural adhesive and preparation method thereof

Abstract

The invention discloses a modified two-component polyurethane structural adhesive and a preparation method thereof, and relates to the technical field of structural adhesives. According to the preparation method, rosin and 1, 4-butanediol are subjected to an esterification reaction to form a cross-linked structure, so that the cohesion among molecules is remarkably improved, the adhesion and durability of the structural adhesive are enhanced, the rigidity of rosin molecules is reduced by an introduced short-chain structure, and the flexibility and elasticity of rosin-based polyol are preliminarily improved; secondly, through combination of polypropylene oxide glycol and epoxidized rosin-based polyol, a long-chain polyether structure of the polypropylene oxide glycol is introduced into the rosin-based polyol, so that on one hand, the viscosity of the rosin-based polyol can be improved, the reaction activity can be increased, and the curing speed with isocyanate is accelerated; and on the other hand, the flexibility of the rosin-based polyether polyol can be further improved, so that the rosin-based polyether polyol generates a rigid-flexible synergistic effect in the structural adhesive.

Description

Technical Field

[0001] The present invention relates to the technical field of structural adhesives, in particular to a modified two-component polyurethane structural adhesive and a preparation method thereof. Background Art

[0002] Two-component polyurethane structural adhesives are high-performance adhesives widely used in a variety of fields, including construction, automotive, aerospace, and electronics. Their key characteristics are high-strength bonding, good mechanical properties, and excellent durability. However, with the increasing demands for material performance in modern industry, the versatility of structural adhesives is being placed on them. Traditional two-component polyurethane structural adhesives still have limitations in certain applications, such as slow cure speed and poor environmental performance.

[0003] In order to overcome the limitations of traditional two-component polyurethane structural adhesives, it is necessary to develop a modified two-component polyurethane structural adhesive by optimizing the raw material formula and modification technology to significantly improve its bonding performance, mechanical properties, weather resistance and environmental protection performance, so that the modified structural adhesive can not only meet the modern industry's demand for high-performance, multifunctional materials, but also maintain stable performance in various complex application environments and reduce harm to the environment and health. Summary of the Invention

[0004] The object of the present invention is to provide a modified two-component polyurethane structural adhesive and a preparation method thereof, so as to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a modified two-component polyurethane structural adhesive, comprising the following preparation steps: S1. Add rosin to the reactor, heat to 160 ° C to completely melt the rosin, then add 1,4-butanediol, add tetrabutyl titanate under nitrogen protection, stir at 140-180 ° C at 300-500 rpm for 4-6 hours, transfer the reaction solution to a centrifuge tube, add ethyl acetate-water solution, centrifuge at 4000-8000 rpm for 10-20 minutes, let it stand for stratification, and take the upper layer. Rotary evaporate at 50 ° C and -0.095 MPa at 60-100 rpm for 1-3 hours, take the solid and dry it at 20 ° C for 12-24 hours, and crush it to obtain rosin-based polyol; S2. The rosin-based polyol obtained in S1 was dissolved in ethyl acetate, and peracetic acid was added dropwise at a rate of 1-2 mL / min at 0-10°C. The mixture was stirred at 100-300 rpm under nitrogen for 4-6 hours. The mixture was rotary evaporated at 60-100 rpm at 50°C and -0.095 MPa for 1-3 hours. The solid was filtered and dried at 60°C for 4-6 hours to obtain an epoxidized rosin-based polyol. S3. The epoxidized rosin-based polyol obtained in S2 was dissolved in toluene, and polyoxypropylene glycol having an average molecular weight of 1199 was added at a stirring speed of 100-300 rpm, heated to 90-110 ° C, and potassium hydroxide was added under nitrogen at the same stirring speed for 6-8 hours. The water generated during the reaction was discharged through a condenser, and the mixture was distilled under reduced pressure at 80 ° C and -0.095 MPa for 2-4 hours. The liquid was filtered and dried at 60 ° C for 2-4 hours to obtain a rosin-based polyether polyol. S4 S3 obtained rosin-based polyether polyol, pentaerythritol ester and a particle size of 15-30nm white carbon black mixed to prepare component A; S5. Polytetrahydrofuran diol having an average molecular weight of 1516 was added to the reaction vessel and heated to 60-80 ° C to completely melt it. Dicyclohexylmethane diisocyanate having an average molecular weight of 262 and dibutyltin dilaurate were added sequentially at a stirring speed of 100-300 rpm. The system was heated to 80-100 ° C, reacted for 2-4h, cooled to room temperature, and the unreacted product was filtered to obtain component B; S6. Component A and component B are mixed in a mass ratio of 2-3:1-1 to prepare a modified two-component polyurethane structural adhesive.

[0006] Furthermore, the ethyl acetate-water mixture described in S1 is prepared by mixing ethyl acetate and deionized water in a mass ratio of 1:1.

[0007] Furthermore, the mass ratio of the rosin, 1,4-butanediol, tetrabutyl titanate and ethyl acetate-water mixture in S1 is 100~100:15~20:0.5~1:100~100.

[0008] Furthermore, the mass ratio of the rosin-based polyol, peracetic acid and ethyl acetate in S2 is 10~10:2~3:10~10.

[0009] Furthermore, the mass ratio of the epoxidized rosin-based polyol, polyoxypropylene glycol, potassium hydroxide and toluene in S3 is 1~1:0.8~1.2:0.01~0.03:2~2.

[0010] Furthermore, the mass ratio of the rosin-based polyether polyol, white carbon black and pentaerythritol ester in S4 is 35-45:10-10:0.5-1.

[0011] Furthermore, the average molecular weight of the polytetrahydrofuran diol described in S5 is 1516, and the number average molecular weight of dicyclohexylmethane diisocyanate is 262.

[0012] Furthermore, the mass ratio of dicyclohexylmethane diisocyanate, polytetrahydrofuran diol and dibutyltin dilaurate described in S5 is 1~1:5.5~6:0.001~0.005.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The modified two-component polyurethane structural adhesive prepared by mixing components A and B with rosin, 1,4-butanediol, polyoxypropylene glycol and filler as main raw materials has durability and a synergistic effect of rigidity and flexibility, and can improve the environmental performance of the two-component polyurethane structural adhesive.

[0014] First, the carboxyl groups of rosin and the hydroxyl groups of 1,4-butanediol react through esterification to form rosin-based polyols. The resulting cross-linked structure retains the heat resistance of the rosin molecules while significantly improving the intermolecular cohesion, allowing the structural adhesive to form a stronger bonding layer during the bonding process, thereby enhancing the adhesion and durability of the structural adhesive. The introduced short-chain structure also reduces the rigidity of the rosin molecules, initially improving the flexibility and elasticity of the rosin-based polyols. Secondly, the double bonds of the rosin-based polyols are epoxidized using peracetic acid to introduce epoxy groups. Through the ring-opening reaction of the hydroxyl groups of polyoxypropylene glycol with the epoxy groups, the long-chain polyether structure of polyoxypropylene glycol is introduced into the rosin-based polyols. On the one hand, this improves the viscosity of the rosin-based polyether polyols and increases their reactivity, thereby accelerating the curing speed with isocyanate, allowing them to be distributed more quickly and evenly on the substrate surface during the coating process. On the other hand, it further enhances the flexibility of the rosin-based polyether polyols, resulting in a synergistic effect of rigidity and flexibility in the structural adhesive. DETAILED DESCRIPTION

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

[0016] In order to more clearly illustrate the method provided by the present invention, the following examples are provided in detail. The test methods for various indicators of a modified two-component polyurethane structural adhesive prepared in the following examples are as follows: Shear strength: Prepare the specimens according to the provisions of GB / T7124-2008. The test substrate is 100×25×1.6mm aluminum alloy (6061). After surface treatment, apply two-component polyurethane structural adhesive with a thickness of 0.2mm. The prepared specimens are placed at 23°C and 50% relative humidity for 7 days, and then loaded at a test speed of 5mm / min. Tensile strength: 1B dumbbell specimens were used for testing according to ISO 527. The prepared specimens were placed under standard test conditions for 7 days and then loaded at a test speed of 10 mm / min. Surface drying time: At 23°C and 50% relative humidity, apply the sealant on a glass plate and test the time it takes until the surface is no longer sticky.

[0017] Example 1 (1) Add 100 parts of rosin by mass to a reactor, heat to 160°C to completely melt the rosin, then add 15 parts of 1,4-butanediol, add 0.5 parts of tetrabutyl titanate under nitrogen protection, stir at 140°C and 300 rpm for 4 hours, transfer the reaction solution to a centrifuge tube, add 100 parts of 50wt% ethyl acetate-water solution, centrifuge at 4000 rpm for 10 minutes, let it stand for stratification, take the upper layer, and perform rotary evaporation at 50°C and -0.095 MPa at 60 rpm for 1 hour. Take the solid and dry it at 20°C for 12 hours, and crush it to obtain rosin-based polyol; (2) Dissolve 10 parts of the rosin-based polyol obtained in step (1) in 10 parts of ethyl acetate, add 2 parts of peracetic acid dropwise at a rate of 1 mL / min at 0°C, stir at 100 rpm for 4 h under nitrogen protection, perform rotary evaporation at 50°C and -0.095 MPa at a speed of 60 rpm for 1 h, filter the solid, and dry it at 60°C for 4 h to obtain epoxidized rosin-based polyol; (3) In parts by mass, 1 part of the epoxidized rosin-based polyol obtained in step (2) was dissolved in 2 parts of toluene, 0.8 parts of polyoxypropylene glycol with an average molecular weight of 1199 was added at a stirring speed of 100 rpm, and the mixture was heated to 90°C. 0.01 parts of potassium hydroxide was added at the same stirring speed under nitrogen protection and the mixture was reacted for 6 hours. The water generated during the reaction was discharged through a condenser, and the mixture was subjected to reduced pressure distillation at 80°C and -0.095 MPa for 2 hours. The liquid was filtered and dried at 60°C for 2 hours to obtain a rosin-based polyether polyol. (4) Component A was prepared by mixing 35 parts by mass of the rosin-based polyether polyol obtained in step (3), 0.5 parts by mass of pentaerythritol ester, and 10 parts by mass of white carbon black having a particle size of 15 nm; (5) In parts by mass, 5.5 parts of polytetrahydrofuran diol with an average molecular weight of 1516 were added to a reaction kettle, heated to 60°C to completely melt it, and 1 part of dicyclohexylmethane diisocyanate with an average molecular weight of 262 and 0.001 part of dibutyltin dilaurate were added in sequence at a stirring speed of 100 rpm. The system was heated to 80°C and reacted for 2 hours. After cooling to room temperature, the unreacted product was filtered to obtain component B; (6) By weight, 2 parts of component A and 1 part of component B are mixed to prepare a modified two-component polyurethane structural adhesive.

[0018] Example 2 (1) Add 100 parts of rosin by mass to a reactor, heat to 160°C to completely melt the rosin, then add 17.5 parts of 1,4-butanediol, add 0.75 parts of tetrabutyl titanate under nitrogen protection, stir at 160°C and 400 rpm for 5 hours, transfer the reaction solution to a centrifuge tube, add 100 parts of 50 wt% ethyl acetate-water solution, centrifuge at 6000 rpm for 15 minutes, let it stand for stratification, take the upper layer, and perform rotary evaporation at 50°C and -0.095 MPa at 80 rpm for 2 hours. Take the solid and dry it at 20°C for 18 hours, and crush it to obtain rosin-based polyol; (2) Dissolve 10 parts of the rosin-based polyol obtained in step (1) in 10 parts of ethyl acetate, add 2.5 parts of peracetic acid dropwise at a rate of 1.5 mL / min at 5°C, stir at 200 rpm under nitrogen protection for 5 h, perform rotary evaporation at 80 rpm at 50°C and -0.095 MPa for 2 h, filter the solid, and dry it at 60°C for 5 h to obtain epoxidized rosin-based polyol; (3) In parts by mass, 1 part of the epoxidized rosin-based polyol obtained in step (2) was dissolved in 2 parts of toluene, 1 part of polyoxypropylene glycol with an average molecular weight of 1199 was added at a stirring speed of 200 rpm, and the mixture was heated to 100°C. 0.02 parts of potassium hydroxide was added at the same stirring speed under nitrogen protection and reacted for 7 hours. The water generated during the reaction was discharged through a condenser, and the mixture was subjected to reduced pressure distillation at 80°C and -0.095 MPa for 3 hours. The liquid was filtered and dried at 60°C for 3 hours to obtain a rosin-based polyether polyol. (4) Component A was prepared by mixing 40 parts by mass of the rosin-based polyether polyol obtained in step (3), 0.75 parts of pentaerythritol ester, and 10 parts of white carbon black having a particle size of 25 nm; (5) In parts by mass, 5.75 parts of polytetrahydrofuran diol with an average molecular weight of 1516 were added to a reaction kettle and heated to 70°C to completely melt it. 1 part of dicyclohexylmethane diisocyanate with an average molecular weight of 262 and 0.003 parts of dibutyltin dilaurate were added in sequence at a stirring speed of 200 rpm. The system was heated to 90°C and reacted for 3 hours. After cooling to room temperature, the unreacted product was filtered to obtain component B; (6) By weight, 2.5 parts of component A and 1 part of component B were mixed to prepare a modified two-component polyurethane structural adhesive.

[0019] Example 3 (1) Add 100 parts of rosin by mass to a reactor, heat to 160°C to completely melt the rosin, then add 20 parts of 1,4-butanediol, add 1 part of tetrabutyl titanate under nitrogen protection, stir at 180°C and 500 rpm for 6 hours, transfer the reaction solution to a centrifuge tube, add 100 parts of 50 wt% ethyl acetate-water solution, centrifuge at 8000 rpm for 20 minutes, let it stand for stratification, take the upper layer, and perform rotary evaporation at 50°C and -0.095 MPa at 100 rpm for 3 hours. Take the solid and dry it at 20°C for 24 hours, and crush it to obtain rosin-based polyol; (2) Dissolve 10 parts of the rosin-based polyol obtained in step (1) in 10 parts of ethyl acetate, add 3 parts of peracetic acid dropwise at a rate of 2 mL / min at 10°C, stir at 300 rpm under nitrogen protection for 6 h, perform rotary evaporation at 50°C, -0.095 MPa, and 100 rpm for 3 h, filter the solid, and dry it at 60°C for 6 h to obtain epoxidized rosin-based polyol; (3) In parts by mass, 1 part of the epoxidized rosin-based polyol obtained in step (2) was dissolved in 2 parts of toluene, 1.2 parts of polyoxypropylene glycol with an average molecular weight of 1199 was added at a stirring speed of 300 rpm, and the mixture was heated to 110°C. 0.03 parts of potassium hydroxide was added at the same stirring speed under nitrogen protection and the mixture was reacted for 8 hours. The water generated during the reaction was discharged through a condenser, and the mixture was subjected to reduced pressure distillation at 80°C and -0.095 MPa for 4 hours. The liquid was filtered and dried at 60°C for 4 hours to obtain a rosin-based polyether polyol. (4) Component A was prepared by mixing 45 parts by mass of the rosin-based polyether polyol obtained in step (3), 1 part by mass of pentaerythritol ester, and 10 parts by mass of white carbon black having a particle size of 30 nm; (5) Add 6 parts by mass of polytetrahydrofuran diol with an average molecular weight of 1516 into a reaction kettle, heat to 80°C to completely melt it, add 1 part of dicyclohexylmethane diisocyanate with an average molecular weight of 262 and 0.005 parts of dibutyltin dilaurate in sequence at a stirring speed of 300 rpm, heat the system to 100°C, react for 4 hours, cool to room temperature, and filter the unreacted product to obtain component B; (6) By weight, 3 parts of component A and 1 part of component B were mixed to prepare a modified two-component polyurethane structural adhesive.

[0020] Comparative Example 1 The difference between Comparative Example 1 and Example 2 lies in the difference in step (1). Step (1) is changed to: 100 parts by mass of rosin are added to a reactor, heated to 160°C to completely melt the rosin, and then 15 parts of 1,4-butanediol are added. Under nitrogen protection, 0.75 parts of tetrabutyl titanate are added, and the mixture is stirred at 160°C and 400 rpm for 5 hours. The reaction solution is transferred to a centrifuge tube, 100 parts of a 50 wt% ethyl acetate-water solution are added, and the mixture is centrifuged at 6000 rpm for 15 minutes. After standing and stratification, the upper layer is taken and rotary evaporated at 80 rpm at 50°C and -0.095 MPa for 2 hours. The solid is dried at 20°C for 18 hours and crushed to obtain a rosin-based polyol.

[0021] Comparative Example 2 The difference between Comparative Example 2 and Example 2 lies in step (2). Step (2) is modified as follows: 10 parts by mass of the rosin-based polyol obtained in step (1) are dissolved in 10 parts of ethyl acetate, 2 parts of peracetic acid are added dropwise at a rate of 1.5 mL / min at 5°C, the mixture is stirred at 200 rpm under nitrogen protection for 5 h, and rotary evaporation is performed at 80 rpm at 50°C and -0.095 MPa for 2 h. The solid is filtered and dried at 60°C for 5 h to obtain epoxidized rosin-based polyol.

[0022] Comparative Example 3 The difference between Comparative Example 3 and Example 2 lies in the difference in step (3). Step (3) is modified as follows: in parts by mass, 1 part of the epoxidized rosin-based polyol obtained in step (2) is dissolved in 2 parts of toluene, 0.8 parts of polyoxypropylene glycol having an average molecular weight of 1199 is added at a stirring speed of 200 rpm, and the mixture is heated to 100° C., 0.02 parts of potassium hydroxide is added at the same stirring speed under nitrogen protection, and the mixture is reacted for 7 hours. The water generated during the reaction is discharged through a condenser, and the mixture is subjected to reduced pressure distillation at 80° C. and −0.095 MPa for 3 hours. The liquid is filtered and dried at 60° C. for 3 hours to obtain a rosin-based polyether polyol.

[0023] Comparative Example 4 The difference between Comparative Example 4 and Example 2 lies in step (4). Step (4) is changed to: Component A is prepared by mixing 35 parts of the rosin-based polyether polyol obtained in step (3), 0.75 parts of pentaerythritol ester and 10 parts of white carbon black with a particle size of 25 nm, in parts by mass.

[0024] Comparative Example 5 The difference between Comparative Example 5 and Example 2 lies in the difference in step (5). Step (5) is changed to: in parts by mass, 5.5 parts of polytetrahydrofuran diol with an average molecular weight of 1516 are added to a reaction kettle, heated to 70°C to completely melt it, and 1 part of dicyclohexylmethane diisocyanate with an average molecular weight of 262 and 0.003 parts of dibutyltin dilaurate are added in sequence at a stirring speed of 200 rpm. The system is heated to 90°C, reacted for 3 hours, cooled to room temperature, and the unreacted product is filtered to obtain component B.

[0025] Comparative Example 6 The difference between Comparative Example 6 and Example 2 lies in step (6). Step (6) is changed to: 2 parts by mass of component A and 1 part by mass of component B are mixed to prepare a modified two-component polyurethane structural adhesive.

[0026] Effect Examples Table 1 below shows the performance analysis results of the modified two-component polyurethane structural adhesives of Examples 1 to 3 of the present invention and Comparative Examples 1 to 6.

[0027] Table 1

[0028] From the comparison of the experimental data of shear strength and tensile strength of the embodiment and the comparative example, it can be found that the cross-linked structure formed by the esterification reaction between 1,4-butanediol and rosin used in this product significantly improves the cohesion between rosin molecules, so that the structural adhesive forms a stronger bonding layer during the bonding process, and enhances the adhesion and durability of the structural adhesive, thereby improving the shear strength and tensile strength of the product. In addition, the introduced short-chain structure reduces the rigidity of the rosin molecules and preliminarily improves the flexibility and elasticity of the rosin-based polyol. The use of polyoxypropylene glycol in the epoxidized rosin-based polyol The introduction of a polyether structure offsets the rigidity of the rosin molecules, significantly improving the flexibility and elasticity of the rosin molecules, and also improving the viscosity of the product and increasing its fluidity, so that the structural adhesive can be evenly distributed on the substrate surface during the coating process, thereby further enhancing the shear strength and tensile strength of the structural adhesive. From the comparison of experimental data on the surface-free time, it can be found that the introduction of polyoxypropylene glycol can enable component A of the structural adhesive to react quickly with the isocyanate group in component B, thereby increasing the cross-linking density of the structural adhesive and forming a stable network structure in a shorter time, thereby shortening the surface-free time.

[0029] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A modified two-component polyurethane structural adhesive, prepared by mixing component A and component B, characterized in that: The component A comprises the following preparation steps: S1. Add rosin to the reactor, heat to 160 ° C to completely melt the rosin, then add 1,4-butanediol, add tetrabutyl titanate under nitrogen protection, stir at 140-180 ° C at 300-500 rpm for 4-6 hours, transfer the reaction solution to a centrifuge tube, add ethyl acetate-water solution, centrifuge at 4000-8000 rpm for 10-20 minutes, let it stand for stratification, and take the upper layer. Rotary evaporate at 50 ° C, -0.095 MPa, 60-100 rpm for 1-3 hours, and dry the solid at 20 ° C for 12-24 hours to obtain rosin-based polyol; S2. The rosin-based polyol obtained in S1 was dissolved in ethyl acetate, and peracetic acid was added dropwise at a rate of 1-2 mL / min at 0-10°C. The mixture was stirred at 100-300 rpm under nitrogen for 4-6 hours. The mixture was rotary evaporated at 60-100 rpm at 50°C and -0.095 MPa for 1-3 hours. The solid was filtered and dried at 60°C for 4-6 hours to obtain an epoxidized rosin-based polyol. S3. The epoxidized rosin-based polyol obtained in S2 was dissolved in toluene, polyoxypropylene glycol was added at a stirring speed of 100-300 rpm, and the mixture was heated to 90-110 ° C. Potassium hydroxide was added at the same stirring speed under nitrogen protection and reacted for 6-8 hours. The water generated during the reaction was discharged through a condenser, and the mixture was distilled under reduced pressure at 80 ° C and -0.095 MPa for 2-4 hours. The liquid was filtered and dried at 60 ° C for 2-4 hours to obtain a rosin-based polyether polyol; S4. Component A is prepared by mixing the rosin-based polyether polyol obtained in S3, pentaerythritol ester, and white carbon black having a particle size of 15-30 nm.

2. The modified two-component polyurethane structural adhesive according to claim 1, characterized in that: The component B is prepared by reacting polytetrahydrofuran diol with dicyclohexylmethane diisocyanate.

3. The modified two-component polyurethane structural adhesive according to claim 2, characterized in that: The average molecular weight of the polytetrahydrofuran diol is 1516, and the number average molecular weight of dicyclohexylmethane diisocyanate is 262.

4. The modified two-component polyurethane structural adhesive according to claim 1, characterized in that: The ethyl acetate-water mixture described in S1 is prepared by mixing ethyl acetate with deionized water in a mass ratio of 1:

1.

5. The modified two-component polyurethane structural adhesive according to claim 1, characterized in that: The mass ratio of the rosin, 1,4-butanediol, tetrabutyl titanate and ethyl acetate-water mixture in S1 is 100~100:15~20:0.5~1:100~100.

6. The modified two-component polyurethane structural adhesive according to claim 1, characterized in that: The mass ratio of the rosin-based polyol, peracetic acid and ethyl acetate described in S2 is 10~10:2~3:10~10.

7. The modified two-component polyurethane structural adhesive according to claim 1, characterized in that: The mass ratio of the epoxidized rosin-based polyol, polyoxypropylene glycol, potassium hydroxide and toluene in S3 is 1~1:0.8~1.2:0.01~0.03:2~2.

8. The modified two-component polyurethane structural adhesive according to claim 1, characterized in that: The mass ratio of the rosin-based polyether polyol, white carbon black and pentaerythritol ester described in S4 is 35~45:10~10:0.5~1.

9. The modified two-component polyurethane structural adhesive according to claim 2, characterized in that: The mass ratio of dicyclohexylmethane diisocyanate, polytetramethylene glycol and dibutyltin dilaurate is 1~1:5.5~6:0.001~0.

005.

10. The modified two-component polyurethane structural adhesive according to claim 1, characterized in that: Component A and component B are mixed in a mass ratio of 2-3:1-1 to prepare a modified two-component polyurethane structural adhesive.

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