Room temperature curing polymer, its preparation method and application

Abstract

The application discloses a normal-temperature curing polymer and a preparation method and application thereof, and belongs to the technical field of adhesive preparation, and the preparation method comprises the following steps: respectively dissolving a linear epoxy resin containing an indole group and a bifunctional triazoline dione in solvents to prepare two solutions; and mixing the two solutions to prepare the polymer. The polymer has the advantages of normal-temperature curing, short curing time, strong adhesion and the like, and can effectively solve the problems of high curing temperature, long curing time and poor adhesion of existing adhesives.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of adhesive preparation, and particularly relates to a normal-temperature curing polymer and a preparation method and application thereof. BACKGROUND

[0002] As an adhesive material, adhesives play an important role in modern industry and daily life. With the advancement of technology, the performance requirements of adhesives are constantly improving, 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 which 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 application, mainly in terms of high-temperature curing, long curing time, poor adhesion, and poor solvent resistance.

[0003] The curing process of traditional epoxy adhesive usually relies on heating, which not only increases energy consumption and production cost, but also leads to prolonged curing time. In some cases, this high-temperature curing can also damage the structural integrity of heat-sensitive materials. At the same time, volatile organic compounds (VOCs) during high-temperature curing can pollute the environment. Therefore, there is an urgent need to develop a new type of adhesive to overcome the shortcomings of epoxy adhesive. SUMMARY

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

[0005] To achieve the above-mentioned purposes, the technical solution adopted by the present application to solve its technical problems is:

[0006] A preparation method of a normal-temperature curing polymer, comprising the following steps:

[0007] The linear polymer containing an indole group and the bifunctional triazolin dione are dissolved in a solvent respectively to obtain two solutions; the two solutions are mixed to obtain a mixture.

[0008] Further, the mass ratio of the linear polymer containing an indole group to the bifunctional triazolin dione is 55-65:1.

[0009] Further, the linear polymer containing an indole group is a linear epoxy resin.

[0010] Further, the linear epoxy resin is prepared by dissolving the epoxy resin and tryptamine in DMF, and then reacting at 70-90 DEG C for 10-14 hours.

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

[0012] Further, the solvent is dichloromethane or trichloromethane.

[0013] The above-mentioned bifunctional triazoline dione is prepared by the following method:

[0014] (1) ethyl hydrazine formate and 4,4'-methylene bis(phenyl isocyanate) are respectively dissolved in an organic solvent, and then the two solutions are mixed in a protective atmosphere, and after mixing, the mixture is stirred at room temperature for 1-3 hours, and then heated to 85-95 DEG C, and continues to be stirred for 1-3 hours, and then filtered and washed to obtain a bifunctional amino urea;

[0015] (2) the bifunctional amino urea is dissolved in lye, and refluxed at 90-120 DEG C for 1-3 hours, and then acidified and filtered to obtain a bifunctional urazole;

[0016] (3) the bifunctional urazole and DABCO-Br are co-dissolved in an organic solvent, and stirred at room temperature for 1-3 hours, and then filtered and vacuum concentrated to obtain the bifunctional triazoline dione.

[0017] A normal temperature curing polymer is prepared by the above-mentioned method.

[0018] The above-mentioned normal temperature curing polymer is applied as an adhesive.

[0019] The beneficial effects of the present application are:

[0020] 1. In the present application, the bifunctional triazoline dione (MDI-TAD) is introduced into the linear polymer system containing indole group (EPI), so that the TAD at both ends of the bifunctional triazoline dione is quickly clicked to react with indole to realize polymer network crosslinking, form C-N bond, and thus form a three-dimensional network structure. The adhesive prepared by the method realizes fast bonding at room temperature, and overcomes the curing defects of traditional adhesives.

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

[0022] 3、The adhesive in the application has a wide temperature resistance range, and can resist the erosion of various organic solvents, so it still performs well in complex environments. Moreover, the adhesive can be completely cured in only 4 hours at room temperature, which significantly shortens the curing time, improves the production efficiency and reduces the energy consumption. The adhesive not only greatly shortens the curing time, but also has a wide application potential. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a schematic diagram of lap joint experiment and adhesive reaction;

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

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

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

[0027] Figure 5 It is a comparison diagram of shear strength of the adhesive cured at different environmental temperatures;

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

[0029] Figure 7 It is a diagram of the change of shear strength of the adhesive with storage time;

[0030] Figure 8 It is a load bearing display diagram of the adhesive on wood with a bonding area of 1cm 2 ;

[0031] Figure 9 It is an SEM diagram of the polymer in Example 1. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application, that is, the described examples are only a part of the examples of the present application, but not all the examples.

[0033] Therefore, the detailed description of the provided examples of the present application below is not intended to limit the scope of the claimed present application, but only represents selected examples of the present application. Based on the examples of the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0034] It is to be understood that the terms "first" and "second" and similar relating terms are used merely to distinguish one entity or action from another, but do not necessarily require or imply any such actual relationship or order between such entities or actions. Also, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by an occurrence of "comprising" does not exclude the existence of additional identical elements in the process, method, article, or apparatus including the element.

[0035] The features and characteristics of the present application will be further described in detail below with reference to the embodiments and the accompanying drawings.

[0036] Example 1

[0037] A room temperature curing polymer, the preparation method thereof comprising the following steps:

[0038] (1) Dissolve E51 type epoxy resin (3.92 g, 10 mmol) and tryptamine (1.6 g, 10 mmol) in 5 ml of DMF, and then react at 80°C for 12 h to prepare an indole group-containing linear epoxy resin;

[0039] (2) Dissolve 0.2 g of the indole group-containing linear epoxy resin and 0.0033 g of the bifunctional triazolinone in 1 ml of dichloromethane, respectively, to prepare two solutions; then mix the two solutions and stir to mix at room temperature to prepare a room temperature curing polymer;

[0040] The bifunctional triazolinone is prepared by the following method:

[0041] (1) Dissolve ethyl hydrazinecarboxylate (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, first stir to react at room temperature for 2 h, then heat to 90°C and continue to stir to react for 2 h, cool to room temperature, and then filter and wash to obtain a bifunctional amino urea;

[0042] (2) Dissolve the bifunctional amino urea (86.2 g, 0.188 mol) in 330 ml of potassium hydroxide solution in a nitrogen environment, reflux at 100°C for 1.5 h, cool to room temperature, then add hydrogen chloride to the solution to acidify to pH 1, and filter to obtain a bifunctional urazole;

[0043] (3) Dissolve triethylenediamine (6.73 g, 60.0 mmol, 1 eq) in chloroform (100 mL), then add dropwise a solution of Br2(20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL) thereto, stir the resulting mixture under an inert atmosphere for 1 hour, filter off the yellow precipitate, wash with chloroform (50 mL), and dry in a vacuum oven at 40°C overnight to obtain DABCO-Br;

[0044] (4) Dissolve bifunctional ureazol (2 g, 5.46 mmol, 1 eq) and DABCO-Br (5 g, 3.18 mmol, 0.58 eq) in dichloromethane (30 mL), stir the reaction mixture under a nitrogen atmosphere at room temperature for 2 h, then filter and concentrate under vacuum to obtain the product.

[0045] Use the above ambient-curable polymer as an adhesive.

[0046] Example 2

[0047] An ambient-curable polymer, the preparation method thereof comprising the following steps:

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

[0049] (2) Dissolve 0.2 g of the indole-containing linear epoxy resin and 0.0031 g of bifunctional triazolin-dione in 1 ml dichloromethane, respectively, to obtain two solutions; then mix the two solutions, stir and mix at room temperature to obtain an ambient-curable polymer;

[0050] The bifunctional triazolin-dione is prepared by the following method:

[0051] (1) Dissolve hydrazine carboxylate (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 toluene, respectively, then mix the two solutions under a nitrogen atmosphere, stir and react at room temperature for 2 h, then heat to 90°C and continue to stir and react for 2 h, cool to room temperature, then filter and wash to obtain a bifunctional amino urea;

[0052] (2) Dissolve the bifunctional amino urea (86.2 g, 0.188 mol) in 330 ml potassium hydroxide solution under a nitrogen atmosphere, reflux at 100°C for 1.5 h, cool to room temperature, then add hydrogen chloride thereto to acidify to pH 1, filter to obtain a bifunctional ureazol.

[0053] (3) Dissolve triethylenediamine (6.73 g, 60.0 mmol, 1 eq) in chloroform (100 mL), then add Br2 (20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL) dropwise. Stir the resulting mixture under an inert atmosphere for 1 hour, filter off the yellow precipitate, wash with chloroform (50 mL), and dry overnight in a vacuum oven at 40 °C to obtain DABCO-Br;

[0054] (4) The bifunctional ureazide (2g, 5.46mmol, 1eq) and DABCO-Br (5g, 3.18mmol, 0.58eq) were co-dissolved in dichloromethane (30mL) and stirred at room temperature under nitrogen for 2h. Then the mixture was filtered and concentrated under vacuum to obtain the final product.

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

[0056] Example 3

[0057] A room-temperature curing polymer is prepared by the following steps:

[0058] (1) E51 type epoxy resin (3.92g, 10mmol) and tryptophan (1.6g, 10mmol) were dissolved in 5ml DMF and then reacted at 90℃ for 10h to obtain linear epoxy resin containing indole groups.

[0059] (2) Dissolve 0.2g of linear epoxy resin containing indole group and 0.0036g of bifunctional triazoline dione in 1ml of dichloromethane to prepare two solutions; then mix the two solutions and stir them at room temperature to obtain a room temperature curing polymer.

[0060] The bifunctional triazolinone was prepared using the following method:

[0061] (1) Ethyl hydrazinocarbamate (40.0 g, 0.384 mol, 2 eq) and 4,4'-methylenebis(phenyl isocyanate) (48.0 g, 0.192 mol, 1 eq) were dissolved in 300 ml of toluene, and the two solutions were mixed in a nitrogen atmosphere. After mixing, the mixture was stirred at room temperature for 2 h, then heated to 90 °C and stirred for another 2 h. After cooling to room temperature, the mixture was filtered and washed to obtain a bifunctional aminourea.

[0062] (2) Dissolve the bifunctional amino-urea (86.2 g, 0.188 mol) in 330 ml of potassium hydroxide solution under nitrogen atmosphere, reflux at 100 °C for 1.5 h, cool to room temperature, then add hydrogen chloride to the solution to acidify to pH 1, filter to obtain the bifunctional ureazol;

[0063] (3) Dissolve triethylenediamine (6.73 g, 60.0 mmol, 1 eq) in chloroform (100 mL), then add dropwise a solution of Br2(20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL) to the solution, stir the resulting mixture under inert atmosphere for 1 h, filter off the yellow precipitate, wash with chloroform (50 mL), and dry in a vacuum oven at 40 °C overnight to obtain DABCO-Br;

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

[0065] Use the above room temperature curing polymer as an adhesive.

[0066] Comparative Example 1

[0067] A room temperature curing polymer, the preparation method thereof comprising the following steps:

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

[0069] (2) Dissolve 0.2 g of the indole group-containing epoxidized soybean oil and 0.0033 g of bifunctional triazolin-dione in 1 ml of dichloromethane respectively to obtain two solutions; then mix the two solutions, stir and mix at room temperature to obtain a mixture;

[0070] The bifunctional triazolin-dione is prepared by the following method:

[0071] (1) Dissolve hydrazine carboxylate (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, then mix the two solutions under nitrogen atmosphere, stir the mixture at room temperature for 2 h, then heat to 90 °C and continue to stir for 2 h, cool to room temperature, then filter and wash to obtain the bifunctional amino-urea;

[0072] (2) Dissolve the bifunctional amino-oxadiazole (86.2 g, 0.188 mol) in 330 ml of potassium hydroxide solution under nitrogen atmosphere, reflux at 100°C for 1.5 h, cool to room temperature, then add hydrogen chloride to the solution to acidify to pH 1, filter to obtain the bifunctional oxadiazole;

[0073] (3) Dissolve triethylenediamine (6.73 g, 60.0 mmol, 1 eq) in chloroform (100 mL), then add dropwise a solution of Br2(20.0 g, 0.125 mol, 2.1 eq) in chloroform (100 mL), stir the resulting mixture under inert atmosphere for 1 h, filter off the yellow precipitate, wash with chloroform (50 mL), and dry in a vacuum oven at 40°C overnight to obtain DABCO-Br;

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

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

[0076] Comparative Example 2

[0077] A room temperature curing polymer, the preparation method thereof comprising the following steps:

[0078] (1) Dissolve the E51 type epoxy resin (3.92 g, 10 mmol) and tryptamine (1.6 g, 10 mmol) in 5 ml of DMF, then react at 80°C for 12 h to obtain a linear epoxy resin containing an indole group;

[0079] (2) Dissolve 0.2 g of the linear epoxy resin containing an indole group and 0.0033 g of triazolin dione in 1 ml of dichloromethane, respectively, to obtain two solutions; then mix the two solutions, stir and mix at room temperature to obtain a room temperature curing polymer.

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

[0081] The synthesis reaction process of the bifunctional triazolin dione in Examples 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] The performance of the adhesive prepared in Example 1 was detected, and the specific detection results are shown in Table 1. Figures 1-7 .

[0087] Figure 1 It is a schematic diagram of the lap joint experiment and adhesive reaction;

[0088] Figure 2 It is a schematic diagram of the adhesive bonding performance on different materials; the results show that the adhesive can be bonded on various substrate sheets, and the shear strength after bonding on steel sheets, ceramic sheets, wood sheets and glass sheets reaches 1.3 Mpa, 1.72 Mpa, 6.68 Mpa and 0.52 Mpa respectively, among which the shear strength on wood sheets has reached the level of commercial adhesives, and even better than the shear strength of commercial 502;

[0089] Figure 3 It is a thermogravimetric diagram of the adhesive; the results show that the adhesive begins to decompose at 342.67℃, proving that the adhesive in the application can be used in a higher temperature environment;

[0090] Figure 4 It is a schematic diagram of the change of shear strength of the adhesive after soaking in different solvents; the results show that after soaking the materials bonded with the adhesive 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 application can effectively prevent the erosion of various organic solvents and improve the action time;

[0091] Figure 5 It is a comparison diagram of the shear strength of the adhesive cured at different environmental temperatures; the results show that after the lap joint experiment on wood sheets, the shear strength test is immediately conducted after soaking at different temperatures for 30 min, including low temperature-40℃ and high temperature 100℃, 120℃, 150℃, the shear strength decreases by 50% at-40℃, but still remains at a high level, and the shear strength of the wood sheets does not change significantly at high temperatures, and is about 6 Mpa;

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

[0093] Figure 7 It is a diagram of the change of shear strength of the adhesive with storage time; the results show that after storage for 1 day, 7 days, 14 days and 21 days, the shear strength does not change significantly, and is about 6 Mpa;

[0094] Figure 8The adhesive has a load-bearing capacity of 25 kg on a wood surface with a bonding area of 1 cm 2 The results show that the wood bonded by the adhesive can bear a weight of 25 kg, which proves that the adhesive has a strong bonding capacity.

[0095] Figure 9 The SEM image of the polymer in Example 1 shows that the surface of the adhesive in Example 1 has a layered structure, which is relatively dense, so that it has a good bonding effect.

Claims

1. An application of a room-temperature curing polymer as an adhesive, characterized in that, The preparation method of the room temperature curing polymer is as follows: Two solutions were prepared by dissolving an indole-containing linear polymer and a bifunctional triazolinone in solvents respectively; the two solutions were then mixed to obtain the final product. The mass ratio of the indole-containing linear polymer to the difunctional triazolinone is 55-65:

1. The indole-containing linear polymer is a linear epoxy resin. The linear epoxy resin is prepared by the following method: epoxy resin E51 and tryptophan are dissolved in DMF at a molar ratio of 1-2:1-2, and then reacted at 70-90℃ for 10-14h to obtain the linear epoxy resin. The solvent is dichloromethane or trichloromethane; The bifunctional triazolinone was prepared by the following method: (1) Dissolve ethyl hydrazine carbamate and 4,4'-methylenebis(phenyl isocyanate) in an organic solvent, then mix the two solutions in a protective atmosphere. After mixing, stir the mixture at room temperature for 1-3 hours, then heat it to 85-95℃ and continue stirring for 1-3 hours. After filtration and washing, the bifunctional aminourea is obtained. (2) Dissolve the bifunctional aminourea in an alkaline solution, reflux at 90-120℃ for 1-3 hours, then acidify and filter to obtain bifunctional ureaazole; (3) Dissolve the bifunctional ureaazole and DABCO-Br in an organic solvent, stir the reaction at room temperature for 1-3 hours, then filter and concentrate under vacuum to obtain the product.

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