Low temperature activated adhesive and method of making same

Abstract

This invention discloses a low-temperature activated adhesive and its preparation method, belonging to the field of adhesive technology. The adhesive, by weight, mainly comprises 8-10 parts of polycarbonate polyol with a number-average molecular weight of 3000, 1-3 parts of polycarbonate polyol with a number-average molecular weight of 2000, and 5-7 parts of bio-based PTMEG with a carbon content of 60-70%, combined with a chain extender, a compound isocyanate, a catalyst, a terminator, n-butyl polymethacrylate, and an environmentally friendly solvent. This invention, through the synergistic regulation of the polyol compound system, specific bio-based PTMEG modification, and tackifying components, enables the adhesive to achieve an activation temperature as low as 38℃, and complete activation below 50℃. It also exhibits excellent initial tack, peel strength, and heat aging resistance, perfectly meeting the bonding requirements of heat-sensitive footwear materials. The preparation process is mild and controllable, environmentally friendly, and easy for industrial-scale production.

Description

Technical Field

[0001] This invention belongs to the technical field of polymer adhesive materials, specifically relating to a low-temperature activated adhesive and its preparation method. Background Technology

[0002] With the rapid development of the footwear industry, the application of lightweight, highly elastic, and environmentally friendly heat-sensitive footwear materials (such as low-density EVA foam, modified microfiber fabrics, low-temperature TPU, and 3D-printed elastic footwear materials) continues to increase. These materials have poor thermal stability; when the ambient temperature exceeds 60℃, they are prone to irreversible foaming shrinkage, warping, yellowing degradation, and mechanical property attenuation, making them unsuitable for the activation processes of traditional footwear adhesives.

[0003] Currently, the activation temperature of mainstream commercially available polyurethane adhesives for footwear is generally between 60℃ and 80℃, which cannot meet the bonding and processing requirements of heat-sensitive footwear materials. Even the few adhesives labeled as usable at low temperatures still have several core defects: First, the actual effective activation temperature of most products is still above 50℃, failing to fundamentally prevent heat damage to heat-sensitive footwear materials. Second, to achieve low-temperature activation, methods are generally used to reduce the system's cohesion and softening point, resulting in insufficient initial tack, low peel strength after curing, poor heat aging resistance and weather resistance, and a tendency to delamination and other quality problems, failing to meet the long-term use requirements of footwear products. Third, the formulation systems often use highly toxic aromatic hydrocarbon solvents, with a low proportion of bio-based raw materials, resulting in insufficient environmental performance and failing to meet the green and low-carbon development trend of the footwear industry.

[0004] Therefore, developing an environmentally friendly adhesive that can be fully activated below 50°C while possessing excellent initial tack, bond strength, and weather resistance is a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a polyurethane adhesive that can be fully activated in a low-temperature environment below 50°C, while having excellent initial tack, cured peel strength and heat aging resistance, to meet the long-term use requirements of footwear products.

[0006] To achieve the above objectives, the present invention discloses the following technical solutions: In a first aspect, the present invention provides a low-temperature activated adhesive, said adhesive comprising the following components in parts by weight: 8-10 parts of 3000 molecular weight polyester polyol; 1-3 parts of 2000 molecular weight polyester polyol; Bio-based PTMEG 5-7 parts; Chain extender 0.1-0.2 parts; Isocyanate 0.8-1.6 parts; 0.02-0.05 parts of organotin catalyst; Terminator 0.01-0.02 parts; 2-5 parts of poly(n-butyl methacrylate); 25-35 parts of dimethyl carbonate; Solvent 50-70 parts.

[0007] Preferably, the 3000 molecular weight polyester polyol is a polycarbonate polyol with a number average molecular weight of 3000, a hydroxyl value of 37-39 mgKOH / g, and an acid value ≤0.1 mgKOH / g.

[0008] Preferably, the 2000 molecular weight polyester polyol is a polycarbonate polyol with a number average molecular weight of 2000, a hydroxyl value of 56-58 mgKOH / g, and an acid value ≤0.1 mgKOH / g.

[0009] Preferably, the bio-based PTMEG has a bio-based carbon content of 60-70%, a number-average molecular weight of 2000, a hydroxyl value of 55-57 mgKOH / g, and an acid value of ≤0.05 mgKOH / g.

[0010] Preferably, the chain extender is 1,4-butanediol.

[0011] Preferably, the isocyanate is prepared by compounding isophorone diisocyanate and hexamethylene diisocyanate in a mass ratio of 2:1 to 1:2.

[0012] Preferably, the organotin catalyst is at least one of dibutyltin dilaurate, stannous octoate, di(dodecyl sulfide)dibutyltin, and dibutyltin diacetate.

[0013] Preferably, the terminating agent is anhydrous methanol.

[0014] Preferably, the solvent is at least one of acetone, butanone, and toluene.

[0015] Secondly, the present invention provides a method for preparing the low-temperature activated adhesive described in the second aspect, the preparation method comprising the following steps: Step 1: Put dimethyl carbonate, 3000 molecular weight polyester polyol, 2000 molecular weight polyester polyol, bio-based PTMEG and chain extender into a container, heat and dissolve, and stir evenly. Step 2: Add isocyanate, catalyst, and dimethyl carbonate to the container from Step 1 and react at 77-80°C for 3-4 hours. After the reaction is complete, add a terminator to terminate the reaction. Finally, add polybutyl methacrylate and solvent and stir to mix evenly to obtain the low-temperature activated adhesive.

[0016] The beneficial effects of this invention are: 1. This invention, through the synergistic regulation of polyol system, soft segment modification and tackifying components, enables the prepared adhesive to have an activation temperature as low as 38-43℃, and can achieve complete activation below 50℃, completely avoiding irreversible damage to heat-sensitive shoe materials caused by high temperatures above 60℃. 2. The adhesive prepared by this invention achieves low-temperature activation while also possessing excellent mechanical properties. The initial tack can reach up to 7.2 N / mm, and the peel strength after curing can reach up to 9.6 N / mm. After heat aging at 70°C for 168 hours, the peel strength can still maintain 9.1 N / mm, which meets the standard requirements. Detailed Implementation

[0017] 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 a part of the embodiments of the present invention, and not all of the 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.

[0018] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0019] I. In this invention Polyester polyol ①: Polycarbonate polyol, number average molecular weight 3000, hydroxyl value 37-39 mgKOH / g, acid value ≤0.1 mgKOH / g, commercially available; Polyester polyol ②: Polycarbonate polyol, number average molecular weight 2000, hydroxyl value 56-58 mgKOH / g, acid value ≤0.1 mgKOH / g, commercially available; Bio-based PTMEG: Bio-based polytetramethylene ether glycol, with a bio-based carbon content of 60-70%, a number-average molecular weight of 2000, a hydroxyl value of 55-57 mgKOH / g, and an acid value of ≤0.05 mgKOH / g. It is commercially available.

[0020] II. Low-temperature activated adhesives 1. Example 1 1.1 Raw Materials Polyester polyol ① 8 parts, polyester polyol ② 1 part, bio-based PTMEG 5 parts, 1,4-butanediol 0.1 parts, isophorone diisocyanate (IPDI) 0.4 parts, hexamethylene diisocyanate (HDI) 0.4 parts, dibutyltin dilaurate 0.02 parts, anhydrous methanol 0.01 parts, poly(n-butyl methacrylate) 2 parts, dimethyl carbonate 25 parts, acetone 40 parts, and methyl ethyl ketone 10 parts.

[0021] 1.2 Preparation method of Example 1 The preparation method of Example 1 is as follows: Step 1: Add 9 parts of dimethyl carbonate, 8 parts of polyester polyol ①, 1 part of polyester polyol ②, 5 parts of bio-based PTMEG, and 0.1 parts of chain extender 1,4-butanediol to the reaction vessel. Heat the reaction vessel to 70°C and stir at 100-120 r / min for 60 min to dissolve. After complete dissolution, raise the temperature to 77°C. Step 2: Add 0.4 parts of IPDI to the reactor and stir for 10 minutes. Then add 0.02 parts of dibutyltin dilaurate and start the reaction at 77°C and 110-120 r / min. After reacting for 2 hours, add 0.4 parts of HDI to the reactor and react for 0.5 hours. Then add 8 parts of dimethyl carbonate and react for another 0.5 hours. Add another 8 parts of dimethyl carbonate and react for another 0.5 hours. Stop heating and add 0.01 parts of anhydrous methanol as a terminator. Finally, add 2 parts of n-butyl polymethacrylate, 40 parts of acetone and 10 parts of butanone. Stir and mix evenly to obtain the low-temperature activated adhesive Example 1.

[0022] 2. Example 2 2.1 Raw Materials Polyester polyol ① 9 parts, polyester polyol ② 2 parts, bio-based PTMEG 6 parts, 1,4-butanediol 0.15 parts, isophorone diisocyanate (IPDI) 0.6 parts, hexamethylene diisocyanate (HDI) 0.5 parts, dibutyltin dilaurate 0.03 parts, anhydrous methanol 0.02 parts, poly(n-butyl methacrylate) 3.5 parts, dimethyl carbonate 30 parts, acetone 45 parts, and methyl ethyl ketone 15 parts.

[0023] 2.2 Preparation method of Example 2 The preparation method of Example 2 is as follows: Step 1: Add 10 parts of dimethyl carbonate, 9 parts of polyester polyol ①, 2 parts of polyester polyol ②, 6 parts of bio-based PTMEG, and 0.15 parts of chain extender 1,4-butanediol to the reaction vessel. Heat the reaction vessel to 75°C and stir at 100-120 r / min for 45 min to dissolve. After complete dissolution, raise the temperature to 80°C. Step 2: Add 0.6 parts of IPDI to the reactor and stir for 10 minutes. Then add 0.03 parts of dibutyltin dilaurate and start the reaction at 80℃ and 110-120 r / min. After reacting for 2 hours, add 0.5 parts of HDI to the reactor and react for 0.5 hours. Then add 10 parts of dimethyl carbonate and react for another 0.5 hours. Then add another 10 parts of dimethyl carbonate and react for another 0.5 hours. Stop heating and add 0.02 parts of anhydrous methanol as a terminator. Finally, add 3.5 parts of poly(n-butyl methacrylate), 45 parts of acetone, and 15 parts of butanone. Stir and mix evenly to obtain the low-temperature activated adhesive Example 2.

[0024] 3. Example 3 3.1 Raw Materials Polyester polyol ① 10 parts, polyester polyol ② 3 parts, bio-based PTMEG 7 parts, 1,4-butanediol 0.2 parts, isophorone diisocyanate (IPDI) 0.8 parts, hexamethylene diisocyanate (HDI) 0.8 parts, dibutyltin dilaurate 0.05 parts, anhydrous methanol 0.02 parts, poly(n-butyl methacrylate) 5 parts, dimethyl carbonate 35 parts, acetone 50 parts, and methyl ethyl ketone 20 parts.

[0025] 3.2 Preparation method of Example 3 The preparation method of Example 3 is as follows: Step 1: Add 13 parts of dimethyl carbonate, 10 parts of polyester polyol ①, 3 parts of polyester polyol ②, 7 parts of bio-based PTMEG, and 0.2 parts of chain extender 1,4-butanediol to the reaction vessel. Heat the reaction vessel to 80°C and stir at 100-120 r / min for 60 min to dissolve. After complete dissolution, maintain the temperature at 80°C. Step 2: Add 0.8 parts of IPDI to the reactor and stir for 10 minutes. Then add 0.05 parts of dibutyltin dilaurate and start the reaction at 80℃ and 110-120 r / min. After reacting for 2 hours, add 0.8 parts of HDI to the reactor and react for 0.5 hours. Then add 11 parts of dimethyl carbonate and react for another 0.5 hours. Then add another 11 parts of dimethyl carbonate and react for another 0.5 hours. Stop heating and add 0.02 parts of anhydrous methanol as a terminator. Finally, add 5 parts of poly(n-butyl methacrylate), 50 parts of acetone, and 20 parts of butanone. Stir and mix evenly to obtain the low-temperature activated adhesive Example 3.

[0026] 4. Comparative Example 1 Comparative Example 1 is an adjustment based on Example 2. The difference from Example 2 is that polyester polyol ① is completely replaced with polyester polyol ②. That is, the raw material composition is adjusted to: 11 parts polyester polyol ②, 6 parts bio-based PTMEG, 0.15 parts 1,4-butanediol, 0.6 parts isophorone diisocyanate (IPDI), 0.5 parts hexamethylene diisocyanate (HDI), 0.03 parts dibutyltin dilaurate, 0.02 parts anhydrous methanol, 3.5 parts poly(n-butyl methacrylate), 30 parts dimethyl carbonate, 45 parts acetone, and 15 parts methyl ethyl ketone. The remaining steps and parameters are the same as in Example 2.

[0027] 5. Comparative Example 2 Comparative Example 2 is an adjustment based on Example 2. The difference from Example 2 is that polyester polyol ② is completely replaced with polyester polyol ①. That is, the raw material composition is adjusted to: 11 parts polyester polyol ①, 6 parts bio-based PTMEG, 0.15 parts 1,4-butanediol, 0.6 parts isophorone diisocyanate (IPDI), 0.5 parts hexamethylene diisocyanate (HDI), 0.03 parts dibutyltin dilaurate, 0.02 parts anhydrous methanol, 3.5 parts polymethyl methacrylate, 30 parts dimethyl carbonate, 45 parts acetone, and 15 parts methyl ethyl ketone. The remaining steps and parameters are the same as in Example 2.

[0028] 6. Comparative Example 3 Comparative Example 3 was adjusted based on Example 2. The difference from Example 2 is that all bio-based PTMEG was replaced with non-bio-based PTMEG. That is, the raw material composition was adjusted to: 9 parts polyester polyol ①, 2 parts polyester polyol ②, 6 parts PTMEG, 0.15 parts 1,4-butanediol, 0.6 parts isophorone diisocyanate (IPDI), 0.5 parts hexamethylene diisocyanate (HDI), 0.03 parts dibutyltin dilaurate, 0.02 parts anhydrous methanol, 3.5 parts poly(n-butyl methacrylate), 30 parts dimethyl carbonate, 45 parts acetone, and 15 parts methyl ethyl ketone. The remaining steps and parameters were the same as in Example 2.

[0029] 7. Comparative Example 4 Comparative Example 4 was adjusted based on Example 2. The difference from Example 2 is that the bio-based PTMEG was replaced with bio-based PTMEG with a bio-based carbon content of 95%. That is, the raw material composition was adjusted to: 9 parts of polyester polyol ①, 2 parts of polyester polyol ②, 6 parts of bio-based PTMEG (95% bio-based carbon content), 0.15 parts of 1,4-butanediol, 0.6 parts of isophorone diisocyanate (IPDI), 0.5 parts of hexamethylene diisocyanate (HDI), 0.03 parts of dibutyltin dilaurate, 0.02 parts of anhydrous methanol, 3.5 parts of poly(n-butyl methacrylate), 30 parts of dimethyl carbonate, 45 parts of acetone, and 15 parts of butanone. The remaining steps and parameters were the same as in Example 2.

[0030] 8. Comparative Example 5 Comparative Example 5 was adjusted based on Example 2. The difference from Example 2 is that bio-based PTMEG was missing. The missing amount was made up by allocating the missing amount according to the mass ratio of polyester polyol ① and polyester polyol ②. That is, the raw material composition was adjusted to: 13.9 parts of polyester polyol ①, 3.1 parts of polyester polyol ②, 0.15 parts of 1,4-butanediol, 0.6 parts of isophorone diisocyanate (IPDI), 0.5 parts of hexamethylene diisocyanate (HDI), 0.03 parts of dibutyltin dilaurate, 0.02 parts of anhydrous methanol, 3.5 parts of poly(n-butyl methacrylate), 30 parts of dimethyl carbonate, 45 parts of acetone, and 15 parts of methyl ethyl ketone. The remaining steps and parameters were the same as in Example 2.

[0031] 9. Comparative Example 6 Comparative Example 6 is an adjustment based on Example 2. The difference from Example 2 is that polybutyl methacrylate is missing, and the missing amount is made up with polyester polyol ①. That is, the raw material composition is adjusted to: 12.5 parts of polyester polyol ①, 2 parts of polyester polyol ②, 6 parts of bio-based PTMEG, 0.15 parts of 1,4-butanediol, 0.6 parts of isophorone diisocyanate (IPDI), 0.5 parts of hexamethylene diisocyanate (HDI), 0.03 parts of dibutyltin dilaurate, 0.02 parts of anhydrous methanol, 30 parts of dimethyl carbonate, 45 parts of acetone, and 15 parts of methyl ethyl ketone. The remaining steps and parameters are the same as in Example 2.

[0032] 10. Comparative Example 7 Comparative Example 7 was adjusted based on Example 2. The difference from Example 2 is that polybutyl methacrylate was replaced with polymethyl methacrylate. That is, the raw material composition was adjusted to: 9 parts of polyester polyol ①, 2 parts of polyester polyol ②, 6 parts of bio-based PTMEG, 0.15 parts of 1,4-butanediol, 0.6 parts of isophorone diisocyanate (IPDI), 0.5 parts of hexamethylene diisocyanate (HDI), 0.03 parts of dibutyltin dilaurate, 0.02 parts of anhydrous methanol, 3.5 parts of polymethyl methacrylate, 30 parts of dimethyl carbonate, 45 parts of acetone, and 15 parts of methyl ethyl ketone. The remaining steps and parameters were the same as in Example 2.

[0033] III. Performance Testing 1. Test Items The adhesives prepared in Examples 1-3 and Comparative Examples 1-7 were subjected to performance testing. The specific tests and methods are as follows: Initial tack is referenced to GB 19340-2014 "Adhesives for Shoes and Bags", unit: N / mm; Peel strength is referenced to GB 19340-2014 "Adhesives for Footwear and Bags", unit: N / mm; Heat aging resistance is referenced to GB 19340-2014 "Adhesives for Footwear and Bags", unit: N / mm.

[0034] 2. Test Results The test results for each item are shown in Table 1; Table 1 Performance test results of Examples 1-3 and Comparative Examples 1-7 Note: The heat aging resistance test conditions are: peel strength is tested after heat aging at 70℃ for 168h; the activation temperature criterion is the lowest constant temperature at which the adhesive reaches an initial tack of ≥2.0N / mm; the average value is taken from 3 parallel tests.

[0035] 3. Results Analysis The low-temperature activated adhesives prepared in Examples 1-3 have activation temperatures all below 50°C, which fully meet the bonding requirements of heat-sensitive shoe materials (temperature tolerance ≤60°C), while also possessing excellent initial tack, peel strength after curing, and heat aging resistance. Comparative Example 1 uses only polyester polyol ② with a molecular weight of 2000. The system has a high proportion of hard segments and high molecular chain rigidity, which leads to an increase in glass transition temperature (Tg) and activation temperature of 58℃, far exceeding the service threshold of 50℃. At the same time, insufficient cohesion leads to a significant decrease in heat aging resistance. Comparative Example 2 uses only polyester polyol ① with a molecular weight of 3000. The system has insufficient molecular chain flexibility and poor chain segment mobility at low temperatures. The activation temperature rises to 55℃, and the initial tack decreases significantly, which cannot meet the process requirements of rapid bonding. Examples 1-3 use polyester polyols ① and ② in a mass ratio of (8-10):(1-3) to achieve precise control of the ratio of soft and hard segments in the system. The high molecular weight polyester ensures the cohesiveness and heat resistance of the adhesive, while the low molecular weight polyester gives the molecular chains good low-temperature mobility, ultimately achieving a synergistic improvement in low-temperature activation and mechanical properties.

[0036] Comparative Example 5 completely removed bio-based PTMEG, and the system lost the modifying effect of the low Tg polyether segments, resulting in a significant increase in overall Tg and an activation temperature of 62℃. At the same time, the initial tack, peel strength and aging resistance all showed a significant decrease. Comparative Example 3 replaced bio-based PTMEG with non-bio-based PTMEG. Although the molecular weights were the same, the non-bio-based PTMEG had poorer compatibility with the polyurethane matrix, which led to a decrease in the low-temperature chain mobility of the system, and the activation temperature rose to 48°C, close to the critical value of 50°C. The overall mechanical properties also declined significantly. Comparative Example 4 uses PTMEG with 95% bio-based carbon content. Its molecular structure regularity is significantly improved and its crystallinity is enhanced. However, this hinders the movement of molecular chains at low temperatures, causing the activation temperature to rise to 52°C, which exceeds the usage requirements. Initial tack and aging resistance also deteriorate simultaneously. The 60-70% bio-based carbon content PTMEG specified in this invention retains the low Tg and high flexibility of polyether segments, which can significantly reduce the activation temperature of the system. At the same time, through appropriate bio-based structural regulation, it achieves good compatibility with polyester-polyurethane matrix, and endows the adhesive with better weather resistance and environmentally friendly properties.

[0037] Comparative Example 6 completely removed polybutyl methacrylate, and the system lost the thickening and melt viscosity regulating effect of this component. The initial tack decreased significantly, the activation temperature rose to 51℃, exceeding the use requirement of 50℃, and the bonding performance after curing also decreased accordingly. In Comparative Example 7, polybutyl methacrylate was replaced with polymethyl acrylate. Due to the higher polarity of polymethyl acrylate, its compatibility with the polyurethane matrix was extremely poor, resulting in obvious phase separation in the system. Not only did the activation temperature rise to 53°C, but the overall mechanical properties also deteriorated significantly. Polybutyl methacrylate has good compatibility with the polyurethane matrix of this invention, which can effectively reduce the melt viscosity of the system, promote the activation and spreading of the adhesive at low temperature, and significantly improve the initial tack of the adhesive, thus achieving the process requirement of low-temperature rapid bonding.

[0038] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low temperature activated adhesive, characterized by, The adhesive consists of the following components in parts by weight: 8-10 parts of 3000 molecular weight polyester polyol; 1-3 parts of 2000 molecular weight polyester polyol; Bio-based PTMEG 5-7 parts; Chain extender 0.1-0.2 parts; Isocyanate 0.8-1.6 parts; 0.02-0.05 parts of organotin catalyst; Terminator 0.01-0.02 parts; 2-5 parts of poly(n-butyl methacrylate); 25-35 parts of dimethyl carbonate; Solvent 50-70 parts.

2. The cryogenic-activated adhesive of claim 1, wherein The 3000 molecular weight polyester polyol is a polycarbonate polyol with a number average molecular weight of 3000, a hydroxyl value of 37-39 mgKOH / g, and an acid value ≤0.1 mgKOH / g.

3. The cryogenic-activated adhesive of claim 1, wherein The 2000 molecular weight polyester polyol is a polycarbonate polyol with a number average molecular weight of 2000, a hydroxyl value of 56-58 mgKOH / g, and an acid value of ≤0.1 mgKOH / g.

4. The cryogenic-activated adhesive of claim 1, wherein The bio-based PTMEG has a bio-based carbon content of 60-70%, a number-average molecular weight of 2000, a hydroxyl value of 55-57 mgKOH / g, and an acid value of ≤0.05 mgKOH / g.

5. The cryogenic-activated adhesive of claim 1, wherein The chain extender is 1,4-butanediol.

6. The cryogenic-activated adhesive of claim 1, wherein, The isocyanate is prepared by compounding isophorone diisocyanate and hexamethylene diisocyanate in a mass ratio of 2:1 to 1:

2.

7. The cryogenic-activated adhesive of claim 1, wherein The organotin catalyst is at least one of dibutyltin dilaurate, stannous octoate, di(dodecyl sulfide)dibutyltin, and dibutyltin diacetate.

8. The cryogenic-activated adhesive of claim 1, wherein, The terminating agent is anhydrous methanol.

9. The low-temperature activated adhesive according to claim 1, characterized in that, The solvent is at least one of acetone, butanone, and toluene.

10. The method for preparing the low-temperature activated adhesive according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: Step 1: Put dimethyl carbonate, 3000 molecular weight polyester polyol, 2000 molecular weight polyester polyol, bio-based PTMEG and chain extender into a container, heat and dissolve, and stir evenly. Step 2: Add isocyanate, catalyst, and dimethyl carbonate to the container from Step 1 and react at 77-80°C for 3-4 hours. After the reaction is complete, add a terminator to terminate the reaction. Finally, add polybutyl methacrylate and solvent and stir to mix evenly to obtain the low-temperature activated adhesive.

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