Modified polyurethane adhesive and preparation method thereof

Abstract

The invention relates to a modified polyurethane adhesive and a preparation method thereof, and belongs to the technical field of functional materials and modification. The modified polyurethane adhesive is prepared from the following raw materials by weight: 25 to 50 mL of modified diisononyl phthalate, 10 to 26 mL of diphenylmethane diisocyanate, 7 to 13 mL of 2-hydroxybenzophenone, 5 to 25 g of titanium dioxide, 10 to 29 g of calcium carbonate, 6 to 24 mL of hydroxyl-terminated polyether, 12 to 30 g of a chain extender, 6 to 12 mL of a curing accelerator and 80 to 130 mL of chlorobenzene. According to the prepared modified polyurethane adhesive, important components in a system are modified through a chemical modification method, so that the polyurethane adhesive shows good strong acid and strong alkali resistance and heat resistance in practical application, and the problems that the bonding strength is reduced in a high-temperature environment and the like are solved.

Description

Technical Field

[0001] This invention belongs to the field of functional materials and modification technology, specifically relating to a modified polyurethane adhesive and its preparation method. Background Technology

[0002] One of the main uses of polyurethane (PU) is in the synthesis of polyurethane adhesives. Polyurethane contains urethane groups (-NHCOO-), ester groups (-COO-), and isocyanate groups (-NCO), thus exhibiting high activity and polarity. This allows it to exhibit excellent chemical adhesion to substrates containing active hydrogen, such as plastics (e.g., foamed plastics), wood, fabrics, leather, and other porous materials, as well as smooth materials such as metals, glass, and rubber. Polyurethane adhesives are an important component of the rapidly developing polyurethane product line. With excellent bonding properties, they are widely used in many fields and have become one of the important varieties among the eight major synthetic adhesives.

[0003] In recent years, with the continuous development of industrialization, the application range of adhesives has become increasingly wide. Polyurethane adhesives, due to their excellent performance, have become an indispensable material in industry and daily life. However, some problems also exist in the widespread application of polyurethane adhesives, such as poor resistance to strong acids and alkalis, insufficient bonding strength, and poor heat resistance, making it difficult to meet the bonding requirements of various materials. Therefore, research on the preparation and properties of modified polyurethane adhesives is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a modified polyurethane adhesive and its preparation method, which solves the problems of poor resistance to strong acids and alkalis, insufficient bonding strength, and poor heat resistance in applications.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing a modified polyurethane adhesive includes the following steps: S1. Add hydroxyethyl acrylate, diisononyl phthalate, catalyst, silane coupling agent and deionized water to the reaction vessel in proportion, and carry out the reaction under inert gas conditions. After the reaction is completed, the material temperature drops to 30℃-50℃, and then the solvent is removed by vacuum distillation. S2. Next, vinylpyrrolidone and imidazole tetrahydrochloride were added to the reaction vessel, the temperature was raised and the reaction was continued, then cooled to room temperature, and purified by vacuum distillation to obtain modified diisononyl phthalate. S3. Add chlorobenzene to the reactor, then add modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether and chain extender in sequence to carry out the polymerization reaction. Cool down to maintain the temperature in the reactor at 20-40℃, slowly add titanium dioxide, calcium carbonate and curing accelerator, stir for 30min-1h to obtain modified polyurethane adhesive.

[0006] Furthermore, the reaction conditions in step S1 are: reaction temperature 100℃-130℃, reaction time 4-6 hours.

[0007] Furthermore, the catalyst is stannous octoate, and the silane coupling agent is γ-thiopropyltrimethoxysilane.

[0008] Furthermore, the stirring speed in the reaction vessel is 800-1000 r / min.

[0009] Furthermore, the ratio of hydroxyethyl acrylate, diisononyl phthalate, silane coupling agent, vinylpyrrolidone, imidazole tetrahydrochloride, catalyst, and deionized water is 14-27 mL: 15-41 mL: 13-27 mL: 10-23 mL: 7-13 g: 3-9 g: 150-300 mL.

[0010] Furthermore, the reaction conditions in step S2 are: reaction temperature 80℃-90℃, reaction time 5-7 hours.

[0011] Furthermore, the ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator, and chlorobenzene is 25-50mL: 10-26mL: 7-13mL: 5-25g: 10-29g: 6-24mL: 12-30g: 6-12mL: 80-130mL.

[0012] Furthermore, the reaction conditions in step S3 are: reaction temperature 90℃, reaction time 3-5 hours.

[0013] Furthermore, the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

[0014] Furthermore, the modified polyurethane adhesive comprises the following materials in the following weight ratios: The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 25-50mL: 10-26mL: 7-13mL: 5-25g: 10-29g: 6-24mL: 12-30g: 6-12mL: 80-130mL.

[0015] The beneficial effects of this invention are: (1) The rigid cyclic structure of vinylpyrrolidone in this invention can inhibit the thermal motion of molecular chains at high temperatures, delay the softening of materials, and copolymerize with acrylate monomers to enhance the water resistance and film-forming properties of adhesives; the hydrophobic ester group of diisononyl phthalate can balance the polarity of the system, reduce water absorption, and prevent performance degradation in humid environments; hydroxyethyl acrylate contains acrylate double bonds and hydroxyl groups (-OH), and has both free radical polymerization activity and transesterification ability. As a crosslinking monomer, it can improve the chemical corrosion resistance and adhesion of materials.

[0016] (2) The present invention uses vinylpyrrolidone grafted with diisononyl phthalate, the pyrrolidone group of which has strong polarity and hydrophilicity, which can optimize the compatibility of the material in mixed solvents, reduce phase separation, and improve wettability during bonding; hydroxyethyl acrylate grafted with diisononyl phthalate can enhance the adhesion to other polar substrates, and at the same time improve the bonding force between molecular chains through hydrogen bonding, thereby improving the cohesive strength of the material; the grafting system achieves multi-dimensional synergistic optimization of mechanical properties, processing adaptability and environmental stability through functional group complementarity and molecular chain design.

[0017] (3) Synergistic modification effect of the present invention: Copolymer grafting can form an alternating structure of flexible and rigid segments, taking into account the impact resistance and dimensional stability of the material; the synergistic effect can reduce thermal oxidative degradation, delay yellowing and strength decay through the stabilization reaction of ester groups and hydroxyl groups; the three components synergistically improve the adhesion strength to complex substrates, while maintaining durability in humid and hot environments. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 The modified polyurethane adhesive of this embodiment comprises the following raw materials in the indicated weight proportions: The ratio of hydroxyethyl acrylate, diisononyl phthalate, silane coupling agent, vinylpyrrolidone, imidazole tetrahydrochloride, catalyst and deionized water is 14mL:15mL:13mL:10mL:7g:3g:150mL. The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 25mL:10mL:7mL:5g:10g:6mL:12g:6mL:80mL.

[0020] This embodiment is based on a method for preparing a modified polyurethane adhesive, wherein the method is a chemical grafting modification method to improve the performance of the polyurethane adhesive; The preparation method of this modified diisononyl phthalate includes the following steps: Step 1: Add hydroxyethyl acrylate, diisononyl phthalate, catalyst, silane coupling agent and deionized water to the reaction vessel in proportion. Under inert gas conditions, react at 100℃ for 5 hours. The magnetic stirring speed in the reaction vessel is 900 r / min. Reduce the material temperature in the reaction vessel to 30℃, and then remove the solvent by vacuum distillation to perform the first grafting of diisononyl phthalate. In step one, the catalyst is stannous octoate, and the silane coupling agent is γ-thiopropyltrimethoxysilane; Step 2: Next, add vinylpyrrolidone and imidazole tetrahydrochloride to the reaction vessel, continue stirring and heating to 80°C, react for 6 hours, then cool to room temperature using an ice-water bath, add deionized water for dilution, and purify by vacuum distillation to obtain modified diisononyl phthalate. Step 3: Add chlorobenzene to the reactor, followed by the addition of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether, and chain extender. Raise the temperature to 90°C and stir thoroughly to carry out the polymerization reaction, obtaining hydroxyl-terminated polyurethane prepolymer. After 3 hours, remove chlorobenzene by vacuum distillation, cool down to maintain the temperature in the reactor at 40°C, and slowly add titanium dioxide, calcium carbonate, and curing accelerator. Keep the reactor sealed and stir for 40 minutes, then stop stirring. Finally, pour the adhesive out of the reactor and filter it to obtain the modified polyurethane adhesive. In step three, the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

[0021] Example 2 The modified polyurethane adhesive of this embodiment comprises the following raw materials in the indicated weight proportions: The ratio of hydroxyethyl acrylate, diisononyl phthalate, silane coupling agent, vinylpyrrolidone, imidazole tetrahydrochloride, catalyst and deionized water is 20mL:28mL:20mL:17mL:10g:6g:225mL. The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 37mL:18mL:10mL:15g:19g:15mL:21g:9mL:105mL.

[0022] This embodiment is based on a method for preparing a modified polyurethane adhesive, wherein the method is a chemical grafting modification method to improve the performance of the polyurethane adhesive; The preparation method of this modified diisononyl phthalate includes the following steps: Step 1: Add hydroxyethyl acrylate, diisononyl phthalate, catalyst, silane coupling agent and deionized water to the reaction vessel in proportion. Under inert gas conditions, react at 100℃ for 5 hours. The magnetic stirring speed in the reaction vessel is 900 r / min. Reduce the material temperature in the reaction vessel to 30℃, and then remove the solvent by vacuum distillation to perform the first grafting of diisononyl phthalate. In step one, the catalyst is stannous octoate, and the silane coupling agent is γ-thiopropyltrimethoxysilane; Step 2: Next, add vinylpyrrolidone and imidazole tetrahydrochloride to the reaction vessel, continue stirring and heating to 80°C, react for 6 hours, then cool to room temperature using an ice-water bath, add deionized water for dilution, and purify by vacuum distillation to obtain modified diisononyl phthalate. Step 3: Add chlorobenzene to the reactor, followed by the addition of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether, and chain extender. Raise the temperature to 90°C and stir thoroughly to carry out the polymerization reaction, obtaining hydroxyl-terminated polyurethane prepolymer. After 3 hours, remove chlorobenzene by vacuum distillation, cool down to maintain the temperature in the reactor at 40°C, and slowly add titanium dioxide, calcium carbonate, and curing accelerator. Keep the reactor sealed and stir for 40 minutes, then stop stirring. Finally, pour the adhesive out of the reactor and filter it to obtain the modified polyurethane adhesive. In step three, the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

[0023] Example 3 The modified polyurethane adhesive of this embodiment comprises the following raw materials in the indicated weight proportions: The ratio of hydroxyethyl acrylate, diisononyl phthalate, silane coupling agent, vinylpyrrolidone, imidazole tetrahydrochloride, catalyst and deionized water is 27mL:41mL:27mL:23mL:13g:9g:300mL. The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 50mL:26mL:13mL:25g:29g:24mL:30g:12mL:130mL.

[0024] This embodiment is based on a method for preparing a modified polyurethane adhesive, wherein the method is a chemical grafting modification method to improve the performance of the polyurethane adhesive; The preparation method of this modified diisononyl phthalate includes the following steps: Step 1: Add hydroxyethyl acrylate, diisononyl phthalate, catalyst, silane coupling agent and deionized water to the reaction vessel in proportion. Under inert gas conditions, react at 100℃ for 5 hours. The magnetic stirring speed in the reaction vessel is 900 r / min. Reduce the material temperature in the reaction vessel to 30℃, and then remove the solvent by vacuum distillation to perform the first grafting of diisononyl phthalate. In step one, the catalyst is stannous octoate, and the silane coupling agent is γ-thiopropyltrimethoxysilane; Step 2: Next, add vinylpyrrolidone and imidazole tetrahydrochloride to the reaction vessel, continue stirring and heating to 80°C, react for 6 hours, then cool to room temperature using an ice-water bath, add deionized water for dilution, and purify by vacuum distillation to obtain modified diisononyl phthalate. Step 3: Add chlorobenzene to the reactor, followed by the addition of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether, and chain extender. Raise the temperature to 90°C and stir thoroughly to carry out the polymerization reaction, obtaining hydroxyl-terminated polyurethane prepolymer. After 3 hours, remove chlorobenzene by vacuum distillation, cool down to maintain the temperature in the reactor at 40°C, and slowly add titanium dioxide, calcium carbonate, and curing accelerator. Keep the reactor sealed and stir for 40 minutes, then stop stirring. Finally, pour the adhesive out of the reactor and filter it to obtain the modified polyurethane adhesive. In step three, the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

[0025] Comparative Example 1 Comparative Example 1 used unmodified diisononyl phthalate and prepared a polyurethane adhesive according to the preparation method of Example 1. The specific steps are as follows: Step 1: Add chlorobenzene to the reactor, followed by diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether, and chain extender. Raise the temperature to 90°C and stir thoroughly to carry out the polymerization reaction to obtain hydroxyl-terminated polyurethane prepolymer. After 3 hours, remove chlorobenzene by vacuum distillation, cool down to maintain the temperature in the reactor at 40°C, and slowly add titanium dioxide, calcium carbonate, and curing accelerator. Keep the reactor sealed and stir for 40 minutes. Finally, pour the adhesive out of the reactor and filter it to obtain the modified polyurethane adhesive. In step one, the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

[0026] Comparative Example 2 Comparative Example 2 used grafted hydroxyethyl acrylate and prepared a polyurethane adhesive according to the preparation method of Example 1. The specific steps are as follows: The modified polyurethane adhesive of this embodiment comprises the following raw materials in the indicated weight proportions: The ratio of hydroxyethyl acrylate, diisononyl phthalate, silane coupling agent, imidazole tetrahydrochloride, catalyst and deionized water is 14mL:15mL:13mL:7g:3g:150mL. The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 25mL:10mL:7mL:5g:10g:6mL:12g:6mL:80mL.

[0027] The preparation method of this modified diisononyl phthalate includes the following steps: Step 1: Add hydroxyethyl acrylate, diisononyl phthalate, catalyst, silane coupling agent and deionized water to the reaction vessel in proportion. Under inert gas conditions, react at 100℃ for 5 hours. The magnetic stirring speed in the reaction vessel is 900 r / min. Reduce the material temperature in the reaction vessel to 30℃, and then remove the solvent by vacuum distillation to perform the first grafting of diisononyl phthalate. In step one, the catalyst is stannous octoate, and the silane coupling agent is γ-thiopropyltrimethoxysilane; Step 2: Next, add tetraimidazole hydrochloride to the reaction vessel, continue stirring and heating to 80°C, react for 6 hours, then cool to room temperature using an ice-water bath, add deionized water for dilution, and purify by vacuum distillation to obtain modified diisononyl phthalate. Step 3: Add chlorobenzene to the reactor, followed by the addition of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether, and chain extender. Raise the temperature to 90°C and stir thoroughly to carry out the polymerization reaction, obtaining hydroxyl-terminated polyurethane prepolymer. After 3 hours, remove chlorobenzene by vacuum distillation, cool down to maintain the temperature in the reactor at 40°C, and slowly add titanium dioxide, calcium carbonate, and curing accelerator. Keep the reactor sealed and stir for 40 minutes, then stop stirring. Finally, pour the adhesive out of the reactor and filter it to obtain the modified polyurethane adhesive. In step three, the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

[0028] Comparative Example 3 Comparative Example 3 used grafted vinylpyrrolidone and prepared a polyurethane adhesive according to the preparation method of Example 1. The specific steps are as follows: The modified polyurethane adhesive of this embodiment comprises the following raw materials in the indicated weight proportions: The ratio of diisononyl phthalate, silane coupling agent, vinylpyrrolidone, imidazole tetrahydrochloride, catalyst and deionized water is 15mL:13mL:10mL:7g:3g:150mL. The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 25mL:10mL:7mL:5g:10g:6mL:12g:6mL:80mL.

[0029] The preparation method of this modified diisononyl phthalate includes the following steps: Step 1: Add vinylpyrrolidone, diisononyl phthalate, catalyst, silane coupling agent and deionized water to the reaction vessel in proportion. Under inert gas conditions, react at 100°C for 5 hours. The magnetic stirring speed in the reaction vessel is 900 r / min. Reduce the material temperature in the reaction vessel to 30°C, and then remove the solvent by vacuum distillation to perform the first grafting of diisononyl phthalate. In step one, the catalyst is stannous octoate, and the silane coupling agent is γ-thiopropyltrimethoxysilane; Step 2: Next, add tetraimidazole hydrochloride to the reaction vessel, continue stirring and heating to 80°C, react for 6 hours, then cool to room temperature using an ice-water bath, add deionized water for dilution, and purify by vacuum distillation to obtain modified diisononyl phthalate. Step 3: Add chlorobenzene to the reactor, followed by the addition of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether, and chain extender. Raise the temperature to 90°C and stir thoroughly to carry out the polymerization reaction, obtaining hydroxyl-terminated polyurethane prepolymer. After 3 hours, remove chlorobenzene by vacuum distillation, cool down to maintain the temperature in the reactor at 40°C, and slowly add titanium dioxide, calcium carbonate, and curing accelerator. Keep the reactor sealed and stir for 40 minutes, then stop stirring. Finally, pour the adhesive out of the reactor and filter it to obtain the modified polyurethane adhesive. In step three, the chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

[0030] To verify the performance of the modified polyurethane adhesive obtained in this invention compared to the examples and comparative examples, conventional index tests were conducted. Viscosity was tested according to GB / T 265-1988, shear strength according to GB / T 7124-2008, post-corrosion refers to the shear strength after immersion in 30% H2SO4 or 30% NaOH for 72 hours, and heat resistance grade according to IEC 60085. The results are shown in the table below:

[0031] As can be seen from the table above, compared with the comparative example, the modified polyurethane adhesive in the examples exhibits good shear strength. Furthermore, regarding shear strength after corrosion, the modified polyurethane adhesive in the examples still demonstrates good performance compared to the comparative example. Under strong acid and alkali conditions, the absolute value of the change rate in the examples is lower than that in the comparative example, indicating that the modified polyurethane adhesive shows less change after immersion in strong acid and alkali, and has better corrosion resistance. After double grafting, the viscosity is significantly enhanced, and the grafting improves the inter-chain bonding force, thus strengthening its adhesion. The heat resistance grades in Examples 1-3 are higher than those in the comparative example, indicating that the modified polyurethane adhesive improves the durability of heat resistance.

[0032] The modified polyurethane adhesive and its preparation method provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention, including the best mode, and also to enable any person skilled in the art to practice this invention, including manufacturing and using any device or system, and implementing any combination method. It should be noted that for those skilled in the art, several improvements and modifications can be made to this invention without departing from the principles of this invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, this invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing a modified polyurethane adhesive, characterized in that, Includes the following steps: S1. Add hydroxyethyl acrylate, diisononyl phthalate, catalyst, silane coupling agent and deionized water to the reaction vessel in proportion, and carry out the reaction under inert gas conditions. After the reaction is completed, the material temperature drops to 30℃-50℃, and then the solvent is removed by vacuum distillation. S2. Next, vinylpyrrolidone and imidazole tetrahydrochloride were added to the reaction vessel, the temperature was raised and the reaction was continued, then cooled to room temperature, and purified by vacuum distillation to obtain modified diisononyl phthalate. S3. Add chlorobenzene to the reactor, then add modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, hydroxyl-terminated polyether and chain extender in sequence to carry out the polymerization reaction. Cool down to maintain the temperature in the reactor at 20-40℃, slowly add titanium dioxide, calcium carbonate and curing accelerator, stir for 30min-1h to obtain modified polyurethane adhesive.

2. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The reaction conditions in step S1 are: reaction temperature 100℃-130℃, reaction time 4-6 hours.

3. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The catalyst is stannous octoate, and the silane coupling agent is γ-thiopropyltrimethoxysilane.

4. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The stirring speed in the reaction vessel is 800-1000 r / min.

5. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The ratio of hydroxyethyl acrylate, diisononyl phthalate, silane coupling agent, vinylpyrrolidone, imidazole tetrahydrochloride, catalyst, and deionized water is 14-27 mL: 15-41 mL: 13-27 mL: 10-23 mL: 7-13 g: 3-9 g: 150-300 mL.

6. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The reaction conditions in step S2 are: reaction temperature 80℃-90℃, reaction time 5-7 hours.

7. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 25-50mL: 10-26mL: 7-13mL: 5-25g: 10-29g: 6-24mL: 12-30g: 6-12mL: 80-130mL.

8. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The reaction conditions in step S3 are: reaction temperature 90℃, reaction time 3-5 hours.

9. The method for preparing a modified polyurethane adhesive according to claim 1, characterized in that, The chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane, and the curing accelerator is ethylene glycol.

10. A method for preparing a modified polyurethane adhesive, characterized in that, The modified polyurethane adhesive prepared by the method according to any one of claims 1-9 comprises the following weight ratios: The ratio of modified diisononyl phthalate, diphenylmethane diisocyanate, 2-hydroxybenzophenone, titanium dioxide, calcium carbonate, hydroxyl-terminated polyether, chain extender, curing accelerator and chlorobenzene is 25-50mL: 10-26mL: 7-13mL: 5-25g: 10-29g: 6-24mL: 12-30g: 6-12mL: 80-130mL.

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