Normal-temperature curing polymer as well as preparation method and application thereof

Abstract

The invention discloses a normal-temperature curing polymer and a preparation method and application thereof, and belongs to the technical field of adhesive preparation, the preparation method comprises the following steps: respectively dissolving indolyl-containing linear epoxy resin and bifunctional triazoline diketone in a solvent to prepare two solutions; and mixing the two solutions to obtain the water-based paint. The polymer has the advantages of normal-temperature curing, short curing time, strong cohesiveness and the like, and can effectively solve the problems of high curing temperature, long curing time, poor cohesiveness and the like of the existing adhesive.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesive preparation, and specifically relates to a room temperature curing polymer and a preparation method and application thereof. Background Art

[0002] As bonding materials, adhesives play an important role in modern industry and daily life. With the advancement of technology, the requirements for adhesive performance are constantly increasing, especially in terms of bonding strength, curing speed, temperature resistance and chemical resistance. Common adhesives on the market include silicone, conductive adhesive, AB adhesive, UV adhesive and epoxy adhesive. Among them, epoxy adhesive has been widely used in aerospace, construction and automotive industries due to its high bonding strength, good temperature resistance and chemical stability. However, epoxy adhesive also has many limitations in practical applications, mainly reflected in the need for high temperature curing, long curing time, poor adhesion and poor solvent resistance.

[0003] The curing process of traditional epoxy adhesives usually relies on heating, which not only increases energy consumption and production costs, but also leads to longer curing time. In some cases, this high-temperature curing may also damage the structural integrity of heat-sensitive materials. At the same time, volatile organic compounds (VOCs) during high-temperature curing will pollute the environment. Therefore, we urgently need to develop a new adhesive to overcome these defects of epoxy adhesives. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a room temperature curing polymer and a preparation method and application thereof. The polymer has the advantages of room temperature curing, short curing time, strong adhesion, etc., and can effectively solve the problems of high curing temperature, long curing time, poor adhesion, etc. of existing adhesives.

[0005] To achieve the above purpose, the technical solution adopted by the present invention to solve the technical problem is:

[0006] A method for preparing a room temperature curing polymer comprises the following steps:

[0007] The indole-containing linear polymer and the difunctional triazolinedione are dissolved in solvents respectively to prepare two solutions; and the two solutions are mixed to prepare the method.

[0008] Furthermore, the mass ratio of the indole-containing linear polymer to the difunctional triazolinedione is 55-65:1.

[0009] Furthermore, the linear polymer containing indole groups is a linear epoxy resin.

[0010] Furthermore, the linear epoxy resin is prepared by the following method: epoxy resin and tryptamine are dissolved in DMF, and then reacted at 70-90° C. for 10-14 hours to obtain the linear epoxy resin.

[0011] Furthermore, the molar ratio of the epoxy resin to the tryptamine is 1-2:1-2.

[0012] Furthermore, the solvent is dichloromethane or chloroform.

[0013] The above-mentioned difunctional triazolinedione is prepared by the following method:

[0014] (1) dissolving ethyl carbazate and 4,4'-methylenebis(phenyl isocyanate) in an organic solvent respectively, and then mixing the two solutions in a protective gas atmosphere, stirring and reacting at room temperature for 1-3 hours, then heating to 85-95° C., stirring and reacting for 1-3 hours, and then filtering and washing to obtain a difunctional semicarbazide;

[0015] (2) dissolving the difunctional semicarbazide in an alkaline solution, reflux at 90-120° C. for 1-3 hours, then acidifying and filtering to obtain a difunctional ureaazole;

[0016] (3) Dissolve the difunctional urea azole and DABCO-Br in an organic solvent, stir and react at room temperature for 1-3 hours, then filter and concentrate in vacuo to obtain the product.

[0017] A room temperature curing polymer is prepared by the above method.

[0018] The above-mentioned room temperature curing polymer is used as an adhesive.

[0019] The beneficial effects produced by the present invention are:

[0020] 1. In the present invention, difunctional triazolinedione (MDI-TAD) is introduced into a linear polymer system (EPI) containing an indole group, so that the TAD at both ends of the difunctional triazolinedione reacts quickly with indole to achieve polymer network crosslinking, forming CN bonds, thereby forming a three-dimensional network structure. The adhesive prepared by this method can achieve rapid bonding at room temperature, overcoming the curing defects of traditional adhesives.

[0021] 2. The adhesive of the present invention can form a strong bonding force on a variety of substrates (such as steel sheets, wood, ceramics and glass), and the shear strength on wood chips can reach 6.47MPa, which is comparable to or even better than the shear strength of existing commercial adhesives on the market.

[0022] 3. The adhesive of the present invention has a wide temperature resistance range and can resist corrosion from a variety of organic solvents, so that it still performs well in complex environments. Moreover, the adhesive can be fully cured in just 4 hours at room temperature. The significantly shortened curing time improves production efficiency and reduces energy consumption. The adhesive not only greatly shortens the curing time, but also shows a wide range of application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the lap joint experiment and adhesive reaction;

[0024] Figure 2 It is a schematic diagram of the bonding performance of adhesives on different materials;

[0025] Figure 3 is the thermogravimetric diagram of the adhesive;

[0026] Figure 4 This is a schematic diagram of the shear strength change of the adhesive after being immersed in different solvents;

[0027] Figure 5 This is a comparison chart of the shear strength of adhesives cured at different ambient temperatures;

[0028] Figure 6 is the glass transition temperature change diagram of the adhesive;

[0029] Figure 7 This is the graph showing the shear strength of the adhesive changing with storage time;

[0030] Figure 8 The adhesive has a bonding area of ​​1cm 2 Load-bearing diagram on wood;

[0031] Fig. 9 This is the SEM image of the polymer in Example 1. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments.

[0033] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0034] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0035] The features and performance of the present invention are further described in detail below in conjunction with the embodiments and drawings.

[0036] Example 1

[0037] A room temperature curing polymer, the preparation method of which comprises the following steps:

[0038] (1) E51 epoxy resin (3.92 g, 10 mmol) and tryptamine (1.6 g, 10 mmol) were dissolved in 5 ml of DMF and reacted at 80° C. for 12 h to obtain an indole-containing linear epoxy resin;

[0039] (2) dissolving 0.2 g of an indole-containing linear epoxy resin and 0.0033 g of a difunctional triazolinedione in 1 ml of dichloromethane to prepare two solutions; then mixing the two solutions and stirring them at room temperature to obtain a room temperature curing polymer;

[0040] Wherein, the difunctional triazolinedione is prepared by the following method:

[0041] (1) Dissolve ethyl carbazate (40.0 g, 0.384 mol, 2 eq) and 4,4'-methylenebis(phenyl isocyanate) (48.0 g, 0.192 mol, 1 eq) in 300 ml of toluene respectively, and then mix the two solutions in a nitrogen atmosphere. After mixing, stir and react at room temperature for 2 h, then heat to 90° C., continue stirring and react for 2 h, cool to room temperature, and then filter and wash to obtain a difunctional semicarbazide;

[0042] (2) Under nitrogen atmosphere, difunctional semicarbazide (86.2 g, 0.188 mol) was dissolved in 330 ml potassium hydroxide solution, refluxed at 100° C. for 1.5 h, cooled to room temperature, and then hydrogen chloride was added thereto to acidify the pH to 1, and filtered to obtain difunctional ureaazole;

[0043] (3) Triethylenediamine (6.73 g, 60.0 mmol, 1 eq) was dissolved in chloroform (100 mL), and Br was added dropwise thereto. 2 (20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL), the resulting mixture was stirred under an inert atmosphere for 1 hour, the yellow precipitate was filtered off, washed with chloroform (50 mL), and dried in a vacuum oven at 40 ° C overnight to obtain DABCO-Br;

[0044] (4) Dissolve difunctional urea azole (2 g, 5.46 mmol, 1 eq) and DABCO-Br (5 g, 3.18 mmol, 0.58 eq) in dichloromethane (30 mL), stir and react under nitrogen at room temperature for 2 h, then filter and concentrate in vacuo to obtain the product.

[0045] The room temperature curing polymer is used as an adhesive.

[0046] Example 2

[0047] A room temperature curing polymer, the preparation method of which comprises the following steps:

[0048] (1) E51 epoxy resin (3.92 g, 10 mmol) and tryptamine (1.6 g, 10 mmol) were dissolved in 5 ml of DMF and reacted at 70° C. for 14 h to obtain an indole-containing linear epoxy resin;

[0049] (2) dissolving 0.2 g of an indole-containing linear epoxy resin and 0.0031 g of a difunctional triazolinedione in 1 ml of dichloromethane to prepare two solutions; then mixing the two solutions and stirring them at room temperature to obtain a room temperature curing polymer;

[0050] Wherein, the difunctional triazolinedione is prepared by the following method:

[0051] (1) Dissolve ethyl carbazate (40.0 g, 0.384 mol, 2 eq) and 4,4'-methylenebis(phenyl isocyanate) (48.0 g, 0.192 mol, 1 eq) in 300 ml of toluene respectively, and then mix the two solutions in a nitrogen atmosphere. After mixing, stir and react at room temperature for 2 h, then heat to 90° C., continue stirring and react for 2 h, cool to room temperature, and then filter and wash to obtain a difunctional semicarbazide;

[0052] (2) Under nitrogen atmosphere, difunctional semicarbazide (86.2 g, 0.188 mol) was dissolved in 330 ml potassium hydroxide solution, refluxed at 100° C. for 1.5 h, cooled to room temperature, and then hydrogen chloride was added thereto to acidify the pH to 1, and filtered to obtain difunctional ureaazole;

[0053] (3) Triethylenediamine (6.73 g, 60.0 mmol, 1 eq) was dissolved in chloroform (100 mL), and Br was added dropwise thereto. 2 (20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL), the resulting mixture was stirred under an inert atmosphere for 1 hour, the yellow precipitate was filtered off, washed with chloroform (50 mL), and dried in a vacuum oven at 40 ° C overnight to obtain DABCO-Br;

[0054] (4) Dissolve difunctional urea azole (2 g, 5.46 mmol, 1 eq) and DABCO-Br (5 g, 3.18 mmol, 0.58 eq) in dichloromethane (30 mL), stir and react under nitrogen at room temperature for 2 h, then filter and concentrate in vacuo to obtain the product.

[0055] The room temperature curing polymer is used as an adhesive.

[0056] Example 3

[0057] A room temperature curing polymer, the preparation method of which comprises the following steps:

[0058] (1) E51 epoxy resin (3.92 g, 10 mmol) and tryptamine (1.6 g, 10 mmol) were dissolved in 5 ml of DMF and reacted at 90° C. for 10 h to obtain an indole-containing linear epoxy resin;

[0059] (2) dissolving 0.2 g of an indole-containing linear epoxy resin and 0.0036 g of a difunctional triazolinedione in 1 ml of dichloromethane to prepare two solutions; then mixing the two solutions and stirring them at room temperature to obtain a room temperature curing polymer;

[0060] Wherein, the difunctional triazolinedione is prepared by the following method:

[0061] (1) Dissolve ethyl carbazate (40.0 g, 0.384 mol, 2 eq) and 4,4'-methylenebis(phenyl isocyanate) (48.0 g, 0.192 mol, 1 eq) in 300 ml of toluene respectively, and then mix the two solutions in a nitrogen atmosphere. After mixing, stir and react at room temperature for 2 h, then heat to 90° C., continue stirring and react for 2 h, cool to room temperature, and then filter and wash to obtain a difunctional semicarbazide;

[0062] (2) Under nitrogen atmosphere, difunctional semicarbazide (86.2 g, 0.188 mol) was dissolved in 330 ml potassium hydroxide solution, refluxed at 100° C. for 1.5 h, cooled to room temperature, and then hydrogen chloride was added thereto to acidify the pH to 1, and filtered to obtain difunctional ureaazole;

[0063] (3) Triethylenediamine (6.73 g, 60.0 mmol, 1 eq) was dissolved in chloroform (100 mL), and Br was added dropwise thereto. 2 (20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL), the resulting mixture was stirred under an inert atmosphere for 1 hour, the yellow precipitate was filtered off, washed with chloroform (50 mL), and dried in a vacuum oven at 40 ° C overnight to obtain DABCO-Br;

[0064] (4) Dissolve difunctional urea azole (2 g, 5.46 mmol, 1 eq) and DABCO-Br (5 g, 3.18 mmol, 0.58 eq) in dichloromethane (30 mL), stir and react under nitrogen at room temperature for 2 h, then filter and concentrate in vacuo to obtain the product.

[0065] The room temperature curing polymer is used as an adhesive.

[0066] Comparative Example 1

[0067] A room temperature curing polymer, the preparation method of which comprises the following steps:

[0068] (1) Epoxidized soybean oil (3.92 g, 10 mmol) and tryptamine (1.6 g, 10 mmol) were reacted at 80° C. for 12 h to obtain indole-containing epoxidized soybean oil;

[0069] (2) dissolving 0.2 g of indole-containing epoxy soybean oil and 0.0033 g of difunctional triazolinedione in 1 ml of dichloromethane respectively to prepare two solutions; then mixing the two solutions and stirring at room temperature to obtain a mixture;

[0070] Wherein, the difunctional triazolinedione is prepared by the following method:

[0071] (1) Dissolve ethyl carbazate (40.0 g, 0.384 mol, 2 eq) and 4,4'-methylenebis(phenyl isocyanate) (48.0 g, 0.192 mol, 1 eq) in 300 ml of toluene respectively, and then mix the two solutions in a nitrogen atmosphere. After mixing, stir and react at room temperature for 2 h, then heat to 90° C., continue stirring and react for 2 h, cool to room temperature, and then filter and wash to obtain a difunctional semicarbazide;

[0072] (2) Under nitrogen atmosphere, difunctional semicarbazide (86.2 g, 0.188 mol) was dissolved in 330 ml potassium hydroxide solution, refluxed at 100° C. for 1.5 h, cooled to room temperature, and then hydrogen chloride was added thereto to acidify the pH to 1, and filtered to obtain difunctional ureaazole;

[0073] (3) Triethylenediamine (6.73 g, 60.0 mmol, 1 eq) was dissolved in chloroform (100 mL), and Br was added dropwise thereto. 2 (20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL), the resulting mixture was stirred under an inert atmosphere for 1 hour, the yellow precipitate was filtered off, washed with chloroform (50 mL), and dried in a vacuum oven at 40 ° C overnight to obtain DABCO-Br;

[0074] (4) Dissolve difunctional urea azole (2 g, 5.46 mmol, 1 eq) and DABCO-Br (5 g, 3.18 mmol, 0.58 eq) in dichloromethane (30 mL), stir and react under nitrogen at room temperature for 2 h, then filter and concentrate in vacuo to obtain the product.

[0075] The mixture obtained by the above method is in a solution state and cannot be used as an adhesive.

[0076] Comparative Example 2

[0077] A room temperature curing polymer, the preparation method of which comprises the following steps:

[0078] (1) E51 epoxy resin (3.92 g, 10 mmol) and tryptamine (1.6 g, 10 mmol) were dissolved in 5 ml of DMF and reacted at 80° C. for 12 h to obtain an indole-containing linear epoxy resin;

[0079] (2) 0.2 g of an indole-containing linear epoxy resin and 0.0033 g of triazolinedione are respectively dissolved in 1 ml of dichloromethane to prepare two solutions; the two solutions are then mixed and stirred at room temperature to obtain a room temperature curing polymer.

[0080] The room temperature curing polymer can be used as an adhesive, but the adhesive has poor viscosity, resulting in poor bonding effect.

[0081] The synthesis reaction process of the difunctional triazolinedione in Example 1-3 is as follows:

[0082]

[0083] The synthesis process of the room temperature curing polymer in Examples 1-3 is as follows:

[0084]

[0085] Test example

[0086] Taking the adhesive prepared in Example 1 as an example, its performance was tested. The specific test results are shown in Figure 1-7 .

[0087] Figure 1 Schematic diagram of the lap joint experiment and adhesive reaction;

[0088] Figure 2 The figure is a schematic diagram of the bonding performance of the adhesive on different materials. The results show that the adhesive can be bonded on various substrates. The shear strengths after bonding on steel, ceramic, wood and glass sheets reach the highest 1.3Mpa, 1.72Mpa, 6.68Mpa and 0.52Mpa respectively. The shear strength on wood has reached the level of commercial adhesives and is even better than the shear strength of commercial 502.

[0089] Figure 3 The thermogravimetric diagram of the adhesive shows that the adhesive begins to thermally decompose at 342.67°C, proving that the adhesive in this application can be used in a higher temperature environment.

[0090] Figure 4 The figure is a schematic diagram of the shear strength change of the adhesive after being immersed in different solvents; the results show that after the materials bonded with the adhesive are immersed in water, ethyl acetate, petroleum ether and other solvents for 5 days, the shear strength does not change significantly, proving that the adhesive in the present application can effectively prevent the erosion of various organic solvents and increase the action time;

[0091] Figure 5 This is a comparison chart of the shear strength of adhesives cured at different ambient temperatures. The results show that after the overlap experiment on the wood chips, the shear strength test was immediately carried out after soaking at different temperatures for 30 minutes, including low temperature of -40℃, and high temperature of 100℃, 120℃, and 150℃. At -40℃, the shear strength decreased by 50%, but it was still at a high level. At high temperatures, the shear strength of the wood chips did not change significantly, all at around 6Mpa.

[0092] Figure 6 This is the glass transition temperature change diagram of the adhesive; the results show that the glass transition temperature is 85℃;

[0093] Figure 7The graph of the shear strength of the adhesive changing with storage time shows that the shear strength did not change significantly after 1 day, 7 days, 14 days, and 21 days of storage, and was around 6Mpa.

[0094] Figure 8 The adhesive has a bonding area of ​​1cm 2 The load-bearing display diagram on the wood shows that the wood bonded with the adhesive can bear a weight of 25 kg, proving that the adhesive in this application has extremely strong bonding properties;

[0095] Fig. 9 This is a SEM image of the polymer in Example 1. It can be seen that the surface of the adhesive in Example 1 is a layered structure with a relatively dense structure, which enables it to have a better bonding effect.

Claims

1. A method for preparing a room temperature curing polymer, characterized in that: The following steps are involved: The indole-containing linear polymer and the difunctional triazolinedione are dissolved in solvents respectively to prepare two solutions; and the two solutions are mixed to prepare the method.

2. The method for preparing a room temperature curing polymer according to claim 1, characterized in that: The mass ratio of the indole-containing linear polymer to the difunctional triazolinedione is 55-65:

1.

3. The method for preparing a room temperature curing polymer according to claim 1, characterized in that: The indole-containing linear polymer is a linear epoxy resin.

4. The method for preparing a room temperature curing polymer according to claim 3, characterized in that: The linear epoxy resin is prepared by the following method: epoxy resin and tryptamine are dissolved in DMF, and then reacted at 70-90° C. for 10-14 hours to obtain the linear epoxy resin.

5. The preparation method of room temperature curing polymerization according to claim 4, characterized in that: The molar ratio of epoxy resin to tryptamine is 1-2:1-2.

6. The method for preparing a room temperature curing polymer according to claim 1, characterized in that: The solvent is dichloromethane or chloroform.

7. The method for preparing a room temperature curing polymer according to claim 1, characterized in that: The difunctional triazolinedione is prepared by the following method: (1) dissolving ethyl carbazate and 4,4'-methylenebis(phenyl isocyanate) in an organic solvent respectively, and then mixing the two solutions in a protective gas atmosphere, stirring and reacting at room temperature for 1-3 hours, then heating to 85-95° C., stirring and reacting for 1-3 hours, and then filtering and washing to obtain a difunctional semicarbazide; (2) dissolving the difunctional semicarbazide in alkaline solution, reflux at 90-120° C. for 1-3 h, then acidifying and filtering to obtain the difunctional ureaazole; (3) Dissolve the difunctional urea azole and DABCO-Br in an organic solvent, stir and react at room temperature for 1-3 hours, then filter and concentrate in vacuo to obtain the product.

8. A room temperature curing polymer, characterized in that: The method according to any one of claims 1 to 7 is adopted.

9. Use of the room temperature curing polymer described in claim 8 as an adhesive.

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