Waterborne polyurethane adhesive with low-temperature activating property and preparation method thereof

Abstract

The invention relates to a waterborne polyurethane adhesive with low-temperature activating property and a preparation method thereof, and belongs to the technical field of adhesives. The waterborne polyurethane adhesive with the low-temperature activation property is prepared from the following raw materials: polyol, isocyanate, a surfactant, dibenzoyl peroxide, a plasticizer, dibutyltin dilaurate, an anti-freezing agent, a thickening agent, gamma-aminopropyltriethoxysilane and deionized water. The polytetrahydrofuran glycol and the polyester polyol containing the side chain long-chain alkyl are combined, so that the flexibility and the strength of the adhesive are remarkably improved, the adhesive property and the weather resistance are enhanced, and brittle fracture is avoided; and the surfactant, the antifreeze agent, the plasticizer and gamma-aminopropyltriethoxysilane are added in the preparation process, so that the stability of the emulsion is further improved, the formation of ice crystals at low temperature is inhibited, the flowability, adhesive force and viscidity of the adhesive are improved, and it is ensured that the adhesive still shows excellent performance in a low-temperature environment.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives and relates to a water-based polyurethane adhesive with low-temperature activation and a preparation method thereof. Background Art

[0002] Waterborne polyurethane adhesives are a type of high-performance, environmentally friendly adhesive that uses water as a dispersion medium and polyurethane resin as the main film-forming material to achieve bonding through physical drying, chemical cross-linking and other effects. Compared with traditional solvent-based adhesives, waterborne polyurethane adhesives contain no or less organic solvents, greatly reducing the emission of volatile organic compounds (VOCs), reducing pollution to the environment, and also improving the safety during production and construction. They are widely used in various industries, including shoe manufacturing, textile coatings, automotive interiors and other fields. However, current waterborne polyurethane adhesives still have certain limitations in practical applications. First, compared with solvent-based adhesives, the movement of waterborne polyurethane molecular segments in waterborne polyurethane adhesives is inhibited, resulting in a decrease in the activation rate of polyurethane resins and difficulty in rapid bonding reactions; secondly, the volatilization rate of water under low temperature conditions is significantly slowed down, which not only affects the drying process of the adhesive, but also affects the bonding strength after curing; in addition, low temperature environments are prone to cause problems such as emulsion instability and phase separation in waterborne adhesive systems, resulting in decreased construction performance, etc. These problems need to be solved one by one. Summary of the invention

[0003] The purpose of the present invention is to provide a water-based polyurethane adhesive with low-temperature activation and a preparation method thereof. The present invention uses polytetrahydrofuran diol and a polyester polyol containing a side chain long-chain alkyl as a combination, significantly improving the flexibility and strength of the adhesive, enhancing the bonding performance and weather resistance, and avoiding brittle fracture; in addition, a surfactant, an antifreeze agent, a plasticizer and γ-aminopropyltriethoxysilane are added during the preparation process to further improve the stability of the emulsion, inhibit the formation of ice crystals at low temperatures, improve the fluidity, adhesion and viscosity of the adhesive, and ensure that the adhesive still exhibits excellent performance in a low-temperature environment.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A water-based polyurethane adhesive with low-temperature activation, wherein the raw materials of the water-based polyurethane adhesive with low-temperature activation include, by weight, 6-7 parts of polyol, 1.6-1.8 parts of isocyanate, 0.2-0.3 parts of surfactant, 0.1-0.2 parts of dibenzoyl peroxide, 0.55-0.65 parts of plasticizer, 0.05-0.15 parts of dibutyltin dilaurate, 0.25-0.35 parts of antifreeze agent, 0.1-0.2 parts of thickener, 0.08-0.12 parts of γ-aminopropyltriethoxysilane and 8-20 parts of deionized water.

[0006] Furthermore, the polyol is composed of polytetramethylene glycol and polyester polyol containing side chain long-chain alkyl in a mass ratio of 8.5-9.5:4.7-5.3.

[0007] Furthermore, the preparation method of the polyester polyol containing a side chain long-chain alkyl group is:

[0008] Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and concentrated sulfuric acid are mixed, and the temperature is controlled and stirred. After the temperature is maintained for 4-5 hours, the heating is stopped, and after cooling to 150°C, stearic acid is added, and the mixture is heated to 196-204°C. The mixture is stirred until the acid value is ≤2mgKOH / g, and then the stirring is stopped. The mixture is cooled to room temperature to obtain a polyester polyol containing a long-chain alkyl side chain.

[0009] Furthermore, the mass ratio of adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid is 9.5-10.5:11-12:0.04-0.06:3.8-4.2; and the added amount of concentrated sulfuric acid accounts for 0.5-1wt% of the total mass of adipic acid, 1,4-butanediol and p-toluenesulfonic acid.

[0010] Furthermore, the temperature control refers to heating the room temperature to 95-105°C at a rate of 2-3°C / min, then heating the room temperature to 165-175°C at a rate of 1-2°C / min, and finally heating the room temperature to 200°C at a rate of 0.5-1°C / min; the stirring speed is 20-60rpm.

[0011] Furthermore, the isocyanate is isophorone diisocyanate.

[0012] Furthermore, the surfactant is composed of SMF1730 and polyethylene glycol octylphenyl ether in a mass ratio of 0.3-0.4:0.78-0.9.

[0013] Furthermore, the preparation method comprises the following steps:

[0014] (1) After preparing the raw materials according to weight parts, pre-treating the polyol, adding the polyol and the isocyanate into a reaction kettle, and reacting under nitrogen protection to obtain a polyurethane prepolymer;

[0015] (2) cooling the polyurethane prepolymer to room temperature, adding a surfactant and deionized water, and stirring at a speed of 2000-4000 rpm for 10-20 minutes to obtain an emulsion;

[0016] (3) Add dibenzoyl peroxide, plasticizer, antifreeze agent and dibutyltin dilaurate to the emulsion, stir at 200-600 rpm for 20-30 min, and simultaneously add triethylamine dropwise to adjust the pH to 6-8. Finally, add thickener and γ-aminopropyltriethoxysilane, continue stirring for 10-20 min, cool to room temperature, and let stand for 24 h. Filter through a 0.5 μm filter to obtain an adhesive.

[0017] Furthermore, the pretreatment in step (1) refers to heating the polytetrahydrofuran diol and the polyester polyol containing a side chain long-chain alkyl to 50° C. respectively, and then stirring at a speed of 2000-3000 rpm for 4-8 min.

[0018] Furthermore, the reaction in step (1) is carried out at 60-80° C. until the NCO value reaches 2-4%, and then the reaction is stopped.

[0019] Beneficial effects of the present invention:

[0020] (1) the low glass transition temperature of the polytetrahydrofuran diol in the present invention helps to strengthen the low temperature flexibility of the adhesive, the combination of polytetrahydrofuran diol and the polyester polyol containing the side chain long-chain alkyl not only provides good flexibility and intensity, but also increases the intermolecular interaction force through the side chain long-chain alkyl, thereby improving the bonding properties and weatherability of the adhesive, avoiding the appearance of the brittle fracture phenomenon, and using isocyanate as a cross-linking agent to form a three-dimensional network structure, further strengthening the use performance of the adhesive in a low temperature environment.

[0021] (2) In the process of preparing the adhesive, the present invention also adds surfactants, antifreeze agents, plasticizers, γ-aminopropyltriethoxysilane, etc., which enhances the stability of the emulsion, making the product less likely to stratify during storage and use. At the same time, it can effectively inhibit the formation of ice crystals in the adhesive at low temperatures, improve the fluidity, adhesion and viscosity of the adhesive, and ensure its good performance in a low temperature environment. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0023] Example 1

[0024] A water-based polyurethane adhesive with low temperature activation, the raw materials of the water-based polyurethane adhesive with low temperature activation of this embodiment, in parts by weight, include 6 parts of polyol, 1.6 parts of isocyanate, 0.2 parts of surfactant, 0.1 parts of dibenzoyl peroxide, 0.55 parts of plasticizer, 0.05 parts of dibutyltin dilaurate, 0.25 parts of antifreeze, 0.1 parts of thickener, 0.08 parts of γ-aminopropyltriethoxysilane and 8 parts of deionized water, wherein dibenzoyl peroxide The acyl was purchased from Shandong Liang New Material Technology Co., Ltd.; dibutyltin silicate was purchased from Jilin Huaxin Chemical Co., Ltd.; γ-aminopropyltriethoxysilane was purchased from Wuhan Smack Biotechnology Co., Ltd.; the plasticizer was diisooctyl sebacate, purchased from Pandex (Shanghai) International Trading Co., Ltd.; the antifreeze agent was ethylene glycol, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the thickener was hydroxyethyl cellulose, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0025] The polyol of the present embodiment is composed of polytetrahydrofuran diol and polyester polyol containing side chain long-chain alkyl in a mass ratio of 8.5:4.7. The polytetrahydrofuran diol of the present embodiment is purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0026] The preparation method of the polyester polyol containing side chain long chain alkyl of the present embodiment is:

[0027] Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and concentrated sulfuric acid are mixed, and the mixture is stirred under controlled temperature. The temperature is maintained constant for 4 hours and then heating is stopped. After cooling to 150°C, stearic acid is added, and the mixture is heated to 196°C. The mixture is stirred until the acid value is ≤2mgKOH / g, and then stirring is stopped. The mixture is cooled to room temperature to obtain a polyester polyol containing long-chain alkyl side chains.

[0028] The mass ratio of adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid in this embodiment is 9.5:11:0.04:3.8. Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid are all purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the amount of concentrated sulfuric acid added accounts for 0.5wt% of the total mass of adipic acid, 1,4-butanediol and p-toluenesulfonic acid.

[0029] The temperature control in this embodiment refers to heating the room temperature to 95°C at a rate of 2°C / min, then heating the room temperature to 165°C at a rate of 1°C / min, and finally heating the room temperature to 200°C at a rate of 0.5°C / min; the stirring speed is 20rpm.

[0030] The isocyanate in this embodiment is isophorone diisocyanate, which was purchased from Guan Jiuzhou (Shandong) Energy Technology Co., Ltd.

[0031] The surfactant of this embodiment is composed of SMF1730 and polyethylene glycol octyl phenyl ether in a mass ratio of 0.3:0.78. SMF1730 is purchased from Shenzhen Feifan Biotechnology Co., Ltd., and polyethylene glycol octyl phenyl ether is purchased from Hai'an Petrochemical Plant in Jiangsu Province.

[0032] The preparation method of this embodiment comprises the following steps:

[0033] (1) After preparing the raw materials according to weight parts, pre-treating the polyol, adding the polyol and the isocyanate into a reaction kettle, and reacting under nitrogen protection to obtain a polyurethane prepolymer;

[0034] (2) cooling the polyurethane prepolymer to room temperature, adding a surfactant and deionized water, and stirring at 2000 rpm for 10 min to obtain an emulsion;

[0035] (3) Add dibenzoyl peroxide, plasticizer, antifreeze agent and dibutyltin dilaurate to the emulsion, stir at 200 rpm for 20 min, and simultaneously add triethylamine dropwise to adjust the pH to 6. Finally, add thickener and γ-aminopropyltriethoxysilane, continue stirring for 10 min, cool to room temperature, let stand for 24 h, and filter through a 0.5 μm filter membrane to obtain an adhesive.

[0036] The pretreatment in step (1) of the present embodiment refers to heating the polytetrahydrofuran diol and the polyester polyol containing a side chain long-chain alkyl group to 50° C. respectively, and then stirring at a speed of 2000 rpm for 4 min.

[0037] The reaction in step (1) of this embodiment refers to the reaction at 60° C. until the NCO value reaches 2%, and then the reaction is stopped.

[0038] Example 2

[0039] A water-based polyurethane adhesive with low temperature activation, the raw materials of the water-based polyurethane adhesive with low temperature activation of this embodiment, in parts by weight, include 7 parts of polyol, 1.8 parts of isocyanate, 0.3 parts of surfactant, 0.2 parts of dibenzoyl peroxide, 0.65 parts of plasticizer, 0.15 parts of dibutyltin dilaurate, 0.35 parts of antifreeze, 0.2 parts of thickener, 0.12 parts of γ-aminopropyltriethoxysilane and 20 parts of deionized water, wherein dibenzoyl peroxide Formyl was purchased from Shandong Liang New Material Technology Co., Ltd.; dibutyltin silicate was purchased from Jilin Huaxin Chemical Co., Ltd.; γ-aminopropyltriethoxysilane was purchased from Wuhan Smack Biotechnology Co., Ltd.; the plasticizer was diisooctyl sebacate, purchased from Pandex (Shanghai) International Trading Co., Ltd.; the antifreeze agent was ethylene glycol, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the thickener was hydroxyethyl cellulose, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0040] The polyol of the present embodiment is composed of polytetrahydrofuran diol and polyester polyol containing side chain long-chain alkyl in a mass ratio of 9.5:5.3. The polytetrahydrofuran diol of the present embodiment is purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0041] The preparation method of the polyester polyol containing side chain long chain alkyl of the present embodiment is:

[0042] Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and concentrated sulfuric acid were mixed, and the mixture was stirred under controlled temperature. The temperature was maintained constant for 5 hours and then heating was stopped. After cooling to 150°C, stearic acid was added, and the mixture was heated to 204°C. The mixture was stirred until the acid value was ≤2mgKOH / g, and then stirring was stopped. The mixture was cooled to room temperature to obtain a polyester polyol containing long-chain alkyl side chains.

[0043] The mass ratio of adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid in this embodiment is 10.5:12:0.06:4.2. Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid are all purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the amount of concentrated sulfuric acid added accounts for 1wt% of the total mass of adipic acid, 1,4-butanediol and p-toluenesulfonic acid.

[0044] The temperature control in this embodiment refers to heating the room temperature to 105°C at a rate of 3°C / min, then heating the room temperature to 175°C at a rate of 2°C / min, and finally heating the room temperature to 200°C at a rate of 1°C / min; the stirring speed is 60rpm.

[0045] The isocyanate in this embodiment is isophorone diisocyanate, which was purchased from Guan Jiuzhou (Shandong) Energy Technology Co., Ltd.

[0046] The surfactant of this embodiment is composed of SMF1730 and polyethylene glycol octyl phenyl ether in a mass ratio of 0.4:0.9. SMF1730 is purchased from Shenzhen Feifan Biotechnology Co., Ltd., and polyethylene glycol octyl phenyl ether is purchased from Hai'an Petrochemical Plant in Jiangsu Province.

[0047] The preparation method of this embodiment comprises the following steps:

[0048] (1) After preparing the raw materials according to weight parts, pre-treating the polyol, adding the polyol and the isocyanate into a reaction kettle, and reacting under nitrogen protection to obtain a polyurethane prepolymer;

[0049] (2) cooling the polyurethane prepolymer to room temperature, adding a surfactant and deionized water, and stirring at 4000 rpm for 20 min to obtain an emulsion;

[0050] (3) Add dibenzoyl peroxide, plasticizer, antifreeze agent and dibutyltin dilaurate to the emulsion, stir at 600 rpm for 30 min, and simultaneously add triethylamine dropwise to adjust the pH to 8. Finally, add thickener and γ-aminopropyltriethoxysilane, continue stirring for 20 min, cool to room temperature, let stand for 24 h, and filter through a 0.5 μm filter membrane to obtain an adhesive.

[0051] The pretreatment in step (1) of the present embodiment refers to heating the polytetrahydrofuran diol and the polyester polyol containing a side chain long-chain alkyl group to 50° C. respectively, and then stirring at a speed of 3000 rpm for 8 min.

[0052] The reaction in step (1) of this embodiment refers to the reaction at 80° C. until the NCO value reaches 4%, and then the reaction is stopped.

[0053] Example 3

[0054] A water-based polyurethane adhesive with low temperature activation, the raw materials of the water-based polyurethane adhesive with low temperature activation of this embodiment, in parts by weight, include 6.5 parts of polyol, 1.7 parts of isocyanate, 0.25 parts of surfactant, 0.15 parts of dibenzoyl peroxide, 0.6 parts of plasticizer, 0.1 parts of dibutyltin dilaurate, 0.3 parts of antifreeze, 0.15 parts of thickener, 0.1 parts of γ-aminopropyltriethoxysilane and 14 parts of deionized water, wherein dibenzoyl peroxide Formyl was purchased from Shandong Liang New Material Technology Co., Ltd.; dibutyltin silicate was purchased from Jilin Huaxin Chemical Co., Ltd.; γ-aminopropyltriethoxysilane was purchased from Wuhan Smack Biotechnology Co., Ltd.; the plasticizer was diisooctyl sebacate, purchased from Pandex (Shanghai) International Trading Co., Ltd.; the antifreeze agent was ethylene glycol, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the thickener was hydroxyethyl cellulose, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0055] The polyol of the present embodiment is composed of polytetrahydrofuran diol and a polyester polyol containing a side chain long-chain alkyl group in a mass ratio of 9:5. The polytetrahydrofuran diol of the present embodiment is purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0056] The preparation method of the polyester polyol containing side chain long chain alkyl of the present embodiment is:

[0057] Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and concentrated sulfuric acid are mixed, stirred under temperature control, the temperature is maintained constant for 4.5 hours and then heating is stopped. After cooling to 150°C, stearic acid is added, heated to 200°C, stirred until the acid value is ≤2mgKOH / g, stirring is stopped, and cooled to room temperature to obtain a polyester polyol containing long-chain alkyl side chains.

[0058] In this embodiment, the mass ratio of adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid is 10:11.5:0.05:4. Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid are all purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the amount of concentrated sulfuric acid added accounts for 0.75wt% of the total mass of adipic acid, 1,4-butanediol and p-toluenesulfonic acid.

[0059] The temperature control in this embodiment refers to heating the room temperature to 100°C at a rate of 2.5°C / min, then heating the room temperature to 170°C at a rate of 1.5°C / min, and finally heating the room temperature to 200°C at a rate of 0.75°C / min; the stirring speed is 40rpm.

[0060] The isocyanate in this embodiment is isophorone diisocyanate, which was purchased from Guan Jiuzhou (Shandong) Energy Technology Co., Ltd.

[0061] The surfactant of this embodiment is composed of SMF1730 and polyethylene glycol octyl phenyl ether in a mass ratio of 0.35:0.84. SMF1730 is purchased from Shenzhen Feifan Biotechnology Co., Ltd., and polyethylene glycol octyl phenyl ether is purchased from Hai'an Petrochemical Plant in Jiangsu Province.

[0062] The preparation method of this embodiment comprises the following steps:

[0063] (1) After preparing the raw materials according to weight parts, pre-treating the polyol, adding the polyol and the isocyanate into a reaction kettle, and reacting under nitrogen protection to obtain a polyurethane prepolymer;

[0064] (2) cooling the polyurethane prepolymer to room temperature, adding a surfactant and deionized water, and stirring at 3000 rpm for 15 minutes to obtain an emulsion;

[0065] (3) Add dibenzoyl peroxide, plasticizer, antifreeze agent and dibutyltin dilaurate to the emulsion, stir at 400 rpm for 25 min, and simultaneously add triethylamine dropwise to adjust the pH to 7. Finally, add thickener and γ-aminopropyltriethoxysilane, continue stirring for 15 min, cool to room temperature, let stand for 24 h, and filter through a 0.5 μm filter membrane to obtain an adhesive.

[0066] The pretreatment in step (1) of the present embodiment refers to heating the polytetrahydrofuran diol and the polyester polyol containing a side chain long-chain alkyl group to 50° C. respectively, and then stirring at a speed of 2500 rpm for 6 min.

[0067] The reaction in step (1) of this embodiment refers to the reaction at 70° C. until the NCO value reaches 3%, and then the reaction is stopped.

[0068] Comparative Example 1

[0069] On the basis of Example 3, the polyester polyol containing the side chain long-chain alkyl is removed and replaced with an equal weight of polytetrahydrofuran diol, and other conditions are consistent with Example 3.

[0070] Comparative Example 2

[0071] On the basis of Example 3, the preparation method of the polyester polyol containing a side chain long-chain alkyl group is changed to:

[0072] Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and concentrated sulfuric acid were mixed, heated to 200°C with stirring, the temperature was maintained for 4.5 hours and then the heating was stopped. After cooling to 150°C, stearic acid was added, heated to 200°C, and stirred until the acid value was ≤2mgKOH / g, then stirring was stopped and the mixture was cooled to room temperature to obtain a polyester polyol containing long-chain alkyl side chains.

[0073] Comparative Example 3

[0074] On the basis of Example 3, SMF1730 in the surfactant was removed and replaced with an equal weight of polyethylene glycol octylphenyl ether, and other conditions were consistent with Example 3.

[0075] Comparative Example 4

[0076] On the basis of Example 3, polyethylene glycol octylphenyl ether in the surfactant was removed and replaced with an equal weight of SMF1730. Other conditions were consistent with Example 3.

[0077] The adhesives prepared in Examples 1-3 and Comparative Examples 1-4 were used as samples, and the samples were sprayed on the bonding surface of leather (conforming to GB / T 16799), the spraying thickness was controlled at 0.1-0.2 mm, and the leather was left to air for 3 minutes. The leather surface was folded and cured at room temperature for 2 hours, and then placed in a freezer with the set temperature at -10°C and -20°C, respectively, for 24 hours. After being taken out, the samples were recovered at room temperature, and the initial adhesion T peel strength (kN / m) was tested according to GB / T2791-1995 standard. After repeating the test 3 times, the average value of the results was recorded as shown in Table 1 below.

[0078] Table 1

[0079] Peel strength at -10℃ Peel strength at -20℃ Example 1 5.0 4.4 Example 2 5.1 4.6 Example 3 5.2 4.8 Comparative Example 1 4.8 4.0 Comparative Example 2 4.3 3.2 Comparative Example 3 4.8 4.0 Comparative Example 4 4.9 4.2

[0080] As shown in Table 1, the adhesives prepared in Examples 1-3 of the present invention have good peel strength at -10°C. When the temperature drops to -20°C, although the bonding performance decreases, it still maintains good performance.

[0081] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any indirect modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A water-based polyurethane adhesive with low temperature activation, characterized in that: The raw materials of the water-based polyurethane adhesive with low-temperature activation include, by weight, 6-7 parts of polyol, 1.6-1.8 parts of isocyanate, 0.2-0.3 parts of surfactant, 0.1-0.2 parts of dibenzoyl peroxide, 0.55-0.65 parts of plasticizer, 0.05-0.15 parts of dibutyltin dilaurate, 0.25-0.35 parts of antifreeze agent, 0.1-0.2 parts of thickener, 0.08-0.12 parts of γ-aminopropyltriethoxysilane and 8-20 parts of deionized water.

2. The water-based polyurethane adhesive with low temperature activation according to claim 1, characterized in that: The polyol is composed of polytetrahydrofuran diol and polyester polyol containing side chain long-chain alkyl in a mass ratio of 8.5-9.5:4.7-5.

3.

3. The water-based polyurethane adhesive with low temperature activation according to claim 2, characterized in that: The preparation method of the polyester polyol containing side chain long chain alkyl is: Adipic acid, 1,4-butanediol, p-toluenesulfonic acid and concentrated sulfuric acid are mixed, and the temperature is controlled and stirred. After the temperature is maintained for 4-5 hours, the heating is stopped, and after cooling to 150°C, stearic acid is added, and the mixture is heated to 196-204°C. The mixture is stirred until the acid value is ≤2mgKOH / g, and then the stirring is stopped. The mixture is cooled to room temperature to obtain a polyester polyol containing a long-chain alkyl side chain.

4. The water-based polyurethane adhesive with low temperature activation according to claim 3, characterized in that: The mass ratio of adipic acid, 1,4-butanediol, p-toluenesulfonic acid and stearic acid is 9.5-10.5:11-12:0.04-0.06:3.8-4.2; the added amount of concentrated sulfuric acid accounts for 0.5-1wt% of the total mass of adipic acid, 1,4-butanediol and p-toluenesulfonic acid.

5. The water-based polyurethane adhesive with low temperature activation according to claim 3, characterized in that: The temperature control refers to heating the room temperature to 95-105°C at a rate of 2-3°C / min, then heating the room temperature to 165-175°C at a rate of 1-2°C / min, and finally heating the room temperature to 200°C at a rate of 0.5-1°C / min; the stirring speed is 20-60rpm.

6. The water-based polyurethane adhesive with low temperature activation according to claim 1, characterized in that: The isocyanate is isophorone diisocyanate.

7. The water-based polyurethane adhesive with low temperature activation according to claim 1, characterized in that: The surfactant is composed of SMF1730 and polyethylene glycol octylphenyl ether in a mass ratio of 0.3-0.4:0.78-0.

9.

8. A method for preparing a water-based polyurethane adhesive with low temperature activation according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) After preparing the raw materials according to weight parts, pre-treating the polyol, adding the polyol and the isocyanate into a reaction kettle, and reacting under nitrogen protection to obtain a polyurethane prepolymer; (2) cooling the polyurethane prepolymer to room temperature, adding a surfactant and deionized water, and stirring at a speed of 2000-4000 rpm for 10-20 minutes to obtain an emulsion; (3) Add dibenzoyl peroxide, plasticizer, antifreeze agent and dibutyltin dilaurate to the emulsion, stir at 200-600 rpm for 20-30 min, and simultaneously add triethylamine dropwise to adjust the pH to 6-8. Finally, add thickener and γ-aminopropyltriethoxysilane, continue stirring for 10-20 min, cool to room temperature, and let stand for 24 h. Filter through a 0.5 μm filter to obtain an adhesive.

9. The method for preparing a water-based polyurethane adhesive with low temperature activation according to claim 8, characterized in that: The pretreatment in step (1) refers to heating the polytetrahydrofuran diol and the polyester polyol containing a side chain long-chain alkyl to 50° C. respectively, and then stirring at a speed of 2000-3000 rpm for 4-8 min.

10. The method for preparing a water-based polyurethane adhesive with low temperature activation according to claim 8, characterized in that: The reaction in step (1) is carried out at 60-80° C. until the NCO value reaches 2-4%, and then the reaction is stopped.