A high performance epoxy resin adhesive based on boron trifluoride monoethylamine and methods of making and using the same

Abstract

The application discloses a high-performance epoxy resin adhesive based on boron trifluoride monoethylamine and a preparation and use method thereof. By adding specific triarylsulfonium hexafluorophosphate in the boron trifluoride monoethylamine epoxy resin system, a protonic acid is generated to act on the epoxy group to generate an activated monomer. The activated monomer and the boron trifluoride monoethylamine synergistically act to effectively avoid the generation of low-molecular oxygen-containing cyclic by-products in the boron trifluoride monoethylamine epoxy resin system, solve the problem of poor mechanical properties of the existing epoxy resin adhesive based on boron trifluoride monoethylamine, and significantly shorten the preliminary curing time of the adhesive due to the action of light, effectively avoid the slippage of the adhesive, and realize the pre-bonding. By adding nano metal, the cohesive energy in the system is reduced, and the adhesion of the epoxy resin adhesive to the metal surface is enhanced. In addition, by optimizing and screening the formula, the proportion of triarylsulfonium hexafluorophosphate and boron trifluoride monoethylamine in a specific range is regulated, the generation of low-molecular cyclic epoxy by-products in the system is maximally inhibited, the complete curing of the epoxy resin adhesive is realized, the epoxy resin adhesive reaches the best mechanical properties, and the problems of poor mechanical properties of the existing epoxy resin adhesive based on boron trifluoride monoethylamine and the like are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of epoxy resin adhesives, and particularly relates to a high-performance epoxy resin adhesive based on boron trifluoride monoethylamine and a preparation and use method thereof. BACKGROUND

[0002] Epoxy resin adhesives are a kind of engineering adhesives prepared from epoxy resin base material, curing agent, diluent, accelerator, filler and the like. In recent decades, the epoxy resin adhesives have been widely applied in the fields of household appliances, automobiles, water conservancy and transportation, electronic appliances and aerospace industry due to good bonding performance, good functionality, low price and simple bonding process.

[0003] The epoxy resin adhesives currently applied in the field of electronic appliances have the following problems: 1. high heat curing temperature, which is easy to damage precision electronic devices; 2. two-component composition, which cannot be mixed in advance and is inconvenient to use; 3. long preliminary curing time, which is easy to slip and affects efficiency; and 4. poor environmental protection, and organic solvents such as acetone and N,N-dimethylformamide are used in the preparation process.

[0004] The boron trifluoride monoethylamine is a latent curing agent for epoxy resin, has the advantages of low-temperature curing, and has the characteristics of latency, can be mechanically processed on various immersed parts before curing, and the reaction system formed by the boron trifluoride monoethylamine and the epoxy resin does not need any solvent, is green and environmentally friendly, is single-component composition, and is convenient to operate. Therefore, the epoxy resin adhesive based on the boron trifluoride monoethylamine can solve most of the problems of the prior art epoxy adhesives, but the system also has certain problems. During the reaction process of the boron trifluoride monoethylamine epoxy resin adhesive system, low-molecular oxygen-containing cyclic by-products are generated, the curing is incomplete, and the mechanical properties of the adhesive are affected. At present, the generation of the by-products is generally inhibited by adding a hydroxyl-containing compound, but the method has the following problems: 1. poor mechanical properties, too much hydroxyl-containing compound added to inhibit the generation of the by-products also reduces the relative content of the epoxy resin, resulting in reduced mechanical properties of the adhesive; and 2. long preliminary curing time, which is easy to cause the adhesive to slip, affects the efficiency, and reduces the mechanical properties. Therefore, there is an urgent need for a high-performance epoxy resin adhesive based on boron trifluoride monoethylamine which can solve the above technical problems. SUMMARY

[0005] Based on the deficiencies of the prior art, the present application provides a high-performance epoxy resin adhesive based on boron trifluoride monoethylamine and its preparation and use method. By adding triaryl sulfonium hexafluoroantimonate or triaryl sulfonium hexafluorophosphate (referred to as specific triaryl sulfonium hexafluoroate), a proton acid is generated, which acts on the epoxy group to generate an activated monomer. The activated monomer and boron trifluoride monoethylamine synergistically act to effectively avoid the generation of low molecular oxygen-containing cyclic byproducts, solve the problem of poor mechanical properties of existing epoxy resin adhesives based on boron trifluoride monoethylamine, and significantly shorten the initial curing time of the adhesive due to the action of light, effectively avoiding the slippage of the adhesive and achieving pre-bonding. The present application adds nano metal to reduce the cohesive energy in the system and enhance the adhesion of the epoxy resin adhesive to the metal surface. In addition, by optimizing the formula selection, the proportion of the specific triaryl sulfonium hexafluoroate and boron trifluoride monoethylamine is controlled within a specific range, which not only maximally inhibits the generation of byproducts but also realizes the complete curing of the adhesive, so that the boron trifluoride monoethylamine epoxy resin adhesive achieves the best mechanical properties.

[0006] The present application provides a high-performance epoxy resin adhesive based on boron trifluoride monoethylamine, the raw material composition and weight ratio of which are as follows:

[0007] Epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester 80-95 parts;

[0008] Thermosetting agent boron trifluoride monoethylamine 2.0-8.0 parts;

[0009] Photoinitiator 2.0-12.0 parts;

[0010] Nano metal 0.1-10 parts;

[0011] The photoinitiator is one of triaryl sulfonium hexafluoroantimonate and triaryl sulfonium hexafluorophosphate;

[0012] The ratio of the raw materials should meet the following conditions:

[0013] The proportion of the photoinitiator triaryl sulfonium hexafluoroate and the thermosetting agent boron trifluoride monoethylamine is in the range of 1.0-1.5;

[0014] The nano metal is one or a combination of nano iron powder, nano copper powder and nano aluminum powder.

[0015] The nano metal has a particle size of 30-200 nm.

[0016] Further, the preparation method of the high-performance epoxy resin adhesive based on boron trifluoride monoethylamine comprises the following steps:

[0017] (1) The raw materials are weighed according to the weight ratio;

[0018] (2) adding weighed epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and thermal curing agent boron trifluoride monoethylamine at water bath temperature, and magnetically stirring to obtain system 1;

[0019] (3) adding photo initiator triarylsulfonium hexafluorophosphate to the resin system 1 obtained in step (2), magnetically stirring uniformly under light shielding condition, then adding nano metal and continuing to magnetically stir under light shielding, and placing in ultrasonic wave for ultrasonic dispersion to obtain system 2;

[0020] (4) defoaming the system 2 obtained in step (3) under vacuum condition, and cooling to room temperature to obtain high performance epoxy resin adhesive.

[0021] The water bath temperature in step (2) is 40-70℃.

[0022] The magnetically stirring time in step (3) is 20-90 min, and the stirring rate is 300-600 r / min.

[0023] The ultrasonic power in step (3) is 1000-1800 W, and the ultrasonic time is 5-30 min.

[0024] The vacuum defoaming time in step (4) is 5-30 min.

[0025] Further, the use method of the high performance epoxy resin adhesive based on boron trifluoride monoethylamine comprises using the adhesive after light and thermal curing.

[0026] The light and thermal curing conditions comprise: light wavelength 315-400 nm, irradiation time 1-2 min, temperature 80-120℃, and time 2-6 h.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] (1) The present application adds specific triarylsulfonium hexafluorophosphate in the boron trifluoride monoethylamine epoxy resin adhesive system, utilizes the generated proton acid to act on the epoxy group to generate activated monomer, and the activated monomer and boron trifluoride monoethylamine synergistically act, which can effectively avoid the generation of low molecular oxygen-containing cyclic by-products in the boron trifluoride monoethylamine epoxy resin system, solve the problem of poor mechanical properties of the existing epoxy resin adhesive based on boron trifluoride monoethylamine, and due to the action of light, the initial curing time of the adhesive is significantly shortened, the slippage of the adhesive is effectively avoided, and pre-bonding is realized.

[0029] (2) The present application can maximize the avoidance of by-product generation and achieve the complete curing of the epoxy resin adhesive by optimizing the formulation and screening to control the ratio of triarylsulfonium hexafluoroborate and boron trifluoride monoethylamine to be between 1.0-1.5. When the ratio of triarylsulfonium hexafluoroborate and boron trifluoride monoethylamine is low, i.e., the amount of boron trifluoride monoethylamine is relatively large, the protonic acid generated by triarylsulfonium hexafluoroborate is not enough to completely inhibit the generation of low molecular oxygen-containing cyclic by-products in the boron trifluoride monoethylamine epoxy resin system, which affects the mechanical properties of the adhesive. When the ratio of the two is high, i.e., the amount of boron trifluoride monoethylamine is small, the cross-linking depth of the adhesive curing network is insufficient, which cannot completely cure and also leads to a decrease in the mechanical properties of the adhesive. Therefore, when the ratio of the two is controlled in a specific range of 1.0-1.5, the best mechanical properties can be achieved.

[0030] (3) The present application can reduce the cohesive energy in the system, enhance the interaction between the epoxy resin adhesive and the metal surface, and promote better bonding of the adhesive with the metal material, thereby significantly improving the mechanical properties. DETAILED DESCRIPTION

[0031] 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 with examples and comparative examples.

[0032] In the following examples and comparative examples, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester epoxy resin was purchased from Tianjin Jingdong Chemical Composite Material Co., Ltd., boron trifluoride monoethylamine was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., triarylsulfonium hexafluoroborate was purchased from Wuhan Huaxiang Keqi Biological Technology Co., Ltd., and nano metal was purchased from Shanghai Guangyi Chemical Co., Ltd.

[0033] Example 1

[0034] A high-performance epoxy resin adhesive based on boron trifluoride monoethylamine was prepared from the following weight fractions of raw materials: 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester 86 parts, thermal curing agent boron trifluoride monoethylamine 6.0 parts, photoinitiator triarylsulfonium hexafluoroborate 6.0 parts, and nano iron powder 2.0 parts.

[0035] The preparation method of the above high-performance epoxy resin adhesive comprises the following steps:

[0036] (1) The raw materials were weighed according to the weight fraction;

[0037] (2) The weighed epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and thermal curing agent boron trifluoride monoethylamine were added under a water bath temperature of 55℃, and magnetic stirring was performed at 400r / min for 40min to obtain system 1;

[0038] (3) adding triarylsulfonium hexafluoroantimonate into the resin system 1 obtained in step (2), stirring at 400 r / min under magnetic force in dark for 50 min, then adding nano-iron powder and continuing to stir, placing into 1500W ultrasonic wave for ultrasonic for 15 min, and uniformly dispersing to obtain system 2;

[0039] (4) defoaming the system 2 obtained in step (3) under vacuum for 20 min, and cooling to room temperature to obtain the high-performance epoxy resin adhesive.

[0040] Irradiating the obtained epoxy resin adhesive with light of 365 nm wavelength for 1.5 min, and placing in a 120℃ oven for 4 h, and then the mechanical property test can be performed.

[0041] Example 2

[0042] A high-performance epoxy resin adhesive based on boron trifluoride monoethylamine is prepared from the following raw materials in parts by weight: 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester 84.5 parts, thermal curing agent boron trifluoride monoethylamine 6.0 parts, photoinitiator triarylsulfonium hexafluoroantimonate 7.5 parts, and nano-iron powder 2.0 parts.

[0043] The preparation method of the above high-performance epoxy resin adhesive comprises the following steps:

[0044] (1) weighing each raw material according to parts by weight;

[0045] (2) adding the weighed epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and thermal curing agent boron trifluoride monoethylamine under water bath temperature of 55℃, stirring at 400 r / min under magnetic force for 40 min to obtain system 1;

[0046] (3) adding triarylsulfonium hexafluoroantimonate into the resin system 1 obtained in step (2), stirring at 400 r / min under magnetic force in dark for 50 min, then adding nano-iron powder and continuing to stir under magnetic force in dark, placing into 1500W ultrasonic wave for ultrasonic for 15 min, and uniformly dispersing to obtain system 2;

[0047] (4) defoaming the system 2 obtained in step (3) under vacuum for 20 min, and cooling to room temperature to obtain the high-performance epoxy resin adhesive.

[0048] Irradiating the obtained epoxy resin adhesive with light of 365 nm wavelength for 1.5 min, and placing in a 120℃ oven for 4 h, and then the mechanical property test can be performed.

[0049] Example 3

[0050] A high-performance epoxy resin adhesive based on boron trifluoride monoethylamine is prepared from the following raw materials in parts by weight: 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester 83 parts, thermal curing agent boron trifluoride monoethylamine 6.0 parts, photoinitiator triarylsulfonium hexafluoroantimonate 9.0 parts, and nano-iron powder 2.0 parts.

[0051] The preparation method of the high-performance epoxy resin adhesive described above comprises the following steps:

[0052] (1) The raw materials are weighed according to the parts by weight;

[0053] (2) The weighed epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and the thermal curing agent boron trifluoride monoethylamine are added under a water bath temperature of 55°C, and stirred at a magnetic force of 400 r / min for 40 min to obtain system 1;

[0054] (3) The triarylsulfonium hexafluoroantimonate is added to the resin system 1 obtained in step (2), and stirred at a magnetic force of 400 r / min for 50 min under light shielding conditions, then the nano-iron powder is added and continuously stirred under light shielding, and ultrasonic treatment is performed in a 1500W ultrasonic device for 15 min to obtain a uniform dispersion, thereby obtaining system 2;

[0055] (4) The system 2 obtained in step (3) is degassed under vacuum for 20 min, and cooled to room temperature to obtain the high-performance epoxy resin adhesive.

[0056] The obtained epoxy resin adhesive is irradiated with light of a wavelength of 365 nm for 1.5 min, and placed in an oven at 120°C for 4 h, and then the mechanical properties are tested.

[0057] Comparative Example 1

[0058] A traditional boron trifluoride monoethylamine epoxy resin adhesive is prepared from the following raw materials in parts by weight: 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester 84.5 parts, thermal curing agent boron trifluoride monoethylamine 6.0 parts, polyhydroxy compound (glycerol) 7.5 parts, and nano-iron powder 2.0 parts.

[0059] The preparation method of the high-performance epoxy resin adhesive described above comprises the following steps:

[0060] (1) The raw materials are weighed according to the parts by weight;

[0061] (2) The weighed epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and the thermal curing agent boron trifluoride monoethylamine are added under a water bath temperature of 55°C, and stirred at a magnetic force of 400 r / min for 40 min to obtain system 1;

[0062] (3) The resin system 1 obtained in step (2) is added with a polyhydroxy compound (glycerol), and stirred at 400 r / min under magnetic stirring in the dark for 50 min. Then, nano-iron powder is added, and the stirring is continued under magnetic stirring in the dark. The system is placed in a 1500 W ultrasonic device for ultrasonic treatment for 15 min, and is uniformly dispersed to obtain system 2.

[0063] (4) The system 2 obtained in step (3) is degassed under vacuum for 20 min, and is cooled to room temperature to obtain a traditional boron trifluoride monoethylamine epoxy resin adhesive.

[0064] The obtained traditional epoxy resin adhesive is placed in an oven at 120°C for 4 h, and then subjected to mechanical property testing.

[0065] The shear strength of the corresponding products of Examples 1-3 and Comparative Example 1 is tested on a Sansi CMT universal tensile testing machine, and the testing standard is in accordance with GB / T 7124-2008. The preliminary curing time (the time from a liquid mixture to the initial change to a solid) is determined by a timer.

[0066] The results are as follows:

[0067] Table 1 Results of Examples and Comparative Examples

[0068]

[0069] It can be seen from the above test results that: 1) the high-performance epoxy resin adhesive based on boron trifluoride monoethylamine prepared in the application (Examples 1-3) has a shear strength greatly improved compared to the traditional way of adding a hydroxyl-containing chemical (Comparative Example 1), and the highest shear strength can reach 25.3 MPa, which is 2.18 times that of the comparative example; 2) the preliminary curing time of Examples 1-3 is 1.5 min, while the preliminary curing time of Comparative Example 1 is 90 min, which shows that the adhesive of the application can significantly shorten the preliminary curing time through the action of light, effectively avoid the slippage of the adhesive, and achieve pre-bonding; 3) the ratio of triarylsulfonium hexafluorophosphate to boron trifluoride monoethylamine in Examples 1-3 is 1.00, 1.25 and 1.50, respectively, and when the ratio is 1.25, the shear strength is the highest, which is 25.3 MPa, which is mainly because at this ratio, the low-molecular oxygen-containing cyclic by-product generated in the boron trifluoride monoethylamine epoxy resin adhesive system can be inhibited to the greatest extent, and at the same time, the adhesive can be completely cured, and the two synergistically achieve the best effect; 4) when the ratio of triarylsulfonium hexafluorophosphate to boron trifluoride monoethylamine is low, i.e. the amount of boron trifluoride monoethylamine is relatively large, the protonic acid generated by triarylsulfonium hexafluorophosphate is not enough to completely inhibit the generation of low-molecular oxygen-containing cyclic by-products in the boron trifluoride monoethylamine epoxy resin system, which affects the mechanical properties of the adhesive; when the ratio of the two is high, i.e. the amount of boron trifluoride monoethylamine is small, the cross-linking depth of the adhesive curing network is insufficient, and the adhesive cannot be completely cured, which also leads to a decrease in the mechanical properties of the adhesive.

[0070] In summary, the high-performance epoxy resin adhesive provided by the application solves the problems existing in the prior art epoxy resin adhesive based on boron trifluoride monoethylamine, greatly improves the mechanical properties of the adhesive, significantly shortens the preliminary curing time of the adhesive, solves the problem of slippage of the adhesive, achieves pre-bonding, and makes the adhesive system have good application prospects in the field of electronics and electrical appliances.

[0071] The above examples only express several embodiments of the application, but should not be construed as limiting the scope of the patent of the application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the application, and these all belong to the protection scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

[0072] The above are only examples and comparative examples of the application, and should not be used to limit the application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A high-performance epoxy resin adhesive based on boron trifluoride monoethylamine, characterized in that, Its raw material composition and weight ratio are as follows: 80-95 parts of epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, 2.0-8.0 parts of thermosetting agent boron trifluoride monoethylamine, 2.0-12.0 parts of photoinitiator, and 0.1-10 parts of nano-metal; The photoinitiator is one of triarylthionium hexafluoroantimonate or triarylthionium hexafluorophosphate; The raw material ratio should meet the following conditions: the ratio of photoinitiator to thermosetting agent boron trifluoride monoethylamine in the components should be controlled within the range of 1.0-1.5; The preparation method of the high-performance epoxy resin adhesive based on boron trifluoride monoethylamine includes the following steps: (1) Weigh each raw material according to the weight proportions; (2) Add the weighed epoxy resin 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and thermosetting agent boron trifluoride monoethylamine at a water bath temperature, and stir magnetically to obtain system 1. (3) Add photoinitiator triarylthionium hexafluoroate to system 1 obtained in step (2), stir magnetically under light-proof conditions until uniform, then add nano-metal and continue stirring magnetically under light-proof conditions, place in an ultrasonic bath and sonicate to disperse uniformly to obtain system 2. (4) Degas the system 2 obtained in step (3) under vacuum conditions and cool it to room temperature to obtain a high-performance epoxy resin adhesive.

2. The high-performance epoxy resin adhesive based on boron trifluoride monoethylamine according to claim 1, characterized in that, The nano-metals mentioned therein are one or more combinations of nano-iron powder, nano-copper powder, and nano-aluminum powder.

3. The high-performance epoxy resin adhesive based on boron trifluoride monoethylamine according to claim 1, characterized in that: The nano-metal particles have a diameter between 30 and 200 nm.

4. The high-performance epoxy resin adhesive based on boron trifluoride monoethylamine according to claim 1, characterized in that, In step (2) of the preparation method, the water bath temperature is 40-70℃.

5. The high-performance epoxy resin adhesive based on boron trifluoride monoethylamine according to claim 1, characterized in that, In step (3) of the preparation method, the magnetic stirring time is 20-90 min and the stirring rate is 300-600 r / min.

6. The high-performance epoxy resin adhesive based on boron trifluoride monoethylamine according to claim 1, characterized in that, In step (3) of the preparation method, the ultrasonic power is 1000-1800W and the ultrasonic time is 5-30min.

7. The high-performance epoxy resin adhesive based on boron trifluoride monoethylamine according to claim 1, characterized in that, In step (4) of the preparation method, the vacuum degassing time is 5 to 30 minutes.

8. The high-performance epoxy resin adhesive based on boron trifluoride monoethylamine according to claim 1, wherein the method of use comprises using the adhesive after photo- and heat curing, wherein the photo- and heat curing conditions include: Light wavelength 315-400nm, irradiation time 1-2min; temperature 80-120℃, time 2-6h.

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