Epoxy resin adhesive for OLED (Organic Light Emitting Diode) and preparation method of epoxy resin adhesive

Abstract

The invention provides an epoxy resin adhesive for an OLED (Organic Light Emitting Diode). The epoxy resin adhesive is prepared from the following components in parts by weight: 40-45 parts of epoxy resin E-51, 1.5-2 parts of a curing accelerator, 22-26 parts of a curing agent, 20-25 parts of a diluent, 0.5-1 part of a coupling agent, 20-24 parts of filler and 3-5 parts of an auxiliary agent. The invention also provides a preparation method of the epoxy resin adhesive. The epoxy resin adhesive for the OLED, provided by the invention, has relatively good toughness, heat resistance and water resistance.

Description

Technical Field

[0001] The invention relates to an adhesive, in particular to an epoxy resin adhesive for OLED and a preparation method thereof. Background Art

[0002] With the rapid development of the electronics industry, especially the continuous updating of information technology, OLED (organic light-emitting diode) display screens have become the leader in the field of electronic products. Compared with liquid crystal display (LCD), OLED display screens have been widely used in various electronic products such as mobile phones, car audio, and televisions, and have become an indispensable core component due to their unique performance advantages, such as active light emission, low driving voltage, high light brightness, high light efficiency, wide light viewing angle, fast response speed, ultra-thin and ultra-light, etc.

[0003] At present, the industrialization of OLED still faces great challenges, mainly because OLED devices are not stable enough and have a short service life. Packaging is an important step in protecting OLED devices from external environmental erosion. Traditional frame packaging methods are mostly epoxy resin adhesives, which have the advantages of high packaging flexibility, simple process, and low production cost. However, ordinary epoxy resin adhesives still have problems such as insufficient toughness, low heat resistance, and poor water resistance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an epoxy resin adhesive for OLED, which has good toughness, heat resistance and water resistance.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] An epoxy resin adhesive for OLED is prepared from the following components in parts by weight: 0-45 parts of epoxy resin E-514, 1.5-2 parts of a curing accelerator, 22-26 parts of a curing agent, 20-25 parts of a diluent, 0.5-1 parts of a coupling agent, 20-24 parts of a filler, and 3-5 parts of an auxiliary agent.

[0007] Furthermore, the curing accelerator of the present invention is 2-ethyl-4-methylimidazole, and the curing agent is tetrahydrophthalic anhydride.

[0008] Furthermore, the diluent of the present invention is composed of 1,6-hexanediol diglycidyl ether and propylene glycol methyl ether in a weight ratio of 3:2.

[0009] Furthermore, the coupling agent of the present invention is 3-(glycidyloxypropyl)trimethoxysilane.

[0010] Furthermore, the filler of the present invention is prepared by the following steps:

[0011] (1) mixing poly (3-methylthiophene), 3-methylpyridine and chloroform, heating to 75° C. and reacting for 18 hours to obtain a reactant 1, washing the reactant 1 with anhydrous ethanol for three times and drying to obtain a pretreated thiophene;

[0012] (2) The pretreated thiophene obtained in step (1), aluminum oxide, ammonium persulfate, and N,N-dimethylformamide were mixed, and the mixture was stirred at room temperature for 12 hours to obtain a second reactant. The second reactant was washed three times with deionized water and then freeze-dried to obtain a filler.

[0013] Furthermore, in the preparation step (1) of the filler of the present invention, the ratio of poly 3-methylthiophene, 3-methylpyridine and chloroform is 1 mmol:1.2 mmol:30 mL, the drying temperature is 75° C., and the drying time is 12 hours; in the step (2), the average particle size of alumina is 10 μm, the ratio of pretreated thiophene, alumina, ammonium persulfate and N,N-dimethylformamide obtained in the step (1) is 18 mg:21 mg:10 mg:15 mL, the freeze-drying temperature is -30° C., and the freeze-drying time is 12 hours.

[0014] Furthermore, the auxiliary agent of the present invention is prepared by the following steps:

[0015] N2-(2-methoxyethyl)-2,5-pyridinediamine and monoethyl adipate were mixed, the pH value was adjusted to 4, and then heated to 165°C. After stirring for 10 minutes, triphenyl phosphite and sodium phosphite were added, and the mixture was heated to 185°C and stirred for 4 hours to obtain a reactant. The reactant was filtered under reduced pressure to obtain a filter residue. The filter residue was washed 3 times with anhydrous ethanol and deionized water respectively, and then dried to obtain an auxiliary agent.

[0016] Furthermore, in the preparation step of the auxiliary agent of the present invention, the weight ratio of N2-(2-methoxyethyl)-2,5-pyridinediamine, monoethyl adipate, triphenyl phosphite and sodium phosphite is 30:20:1:1, the drying temperature is 80°C, and the drying time is 12 hours.

[0017] Another technical problem to be solved by the present invention is to provide a method for preparing the epoxy resin adhesive for OLED.

[0018] To solve the above technical problems, the technical solution is:

[0019] A method for preparing an epoxy resin adhesive for OLED, comprising the following steps:

[0020] S1. Weigh each component in parts by weight, mix the epoxy resin E51 with the diluent, and stir for 1-2 hours to obtain a mixture;

[0021] S2. Mix the remaining components with the mixture obtained in step S1, and stir for 3-4 hours to obtain an epoxy resin adhesive for OLED.

[0022] Furthermore, in step S1 of the present invention, the stirring temperature is 20-30°C, and the stirring speed is 300-400rpm; in step S2, the stirring temperature is 20-30°C, and the stirring speed is 200-300rpm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) Alumina has good heat resistance and mechanical properties, but its compatibility with epoxy resin is poor and it cannot be well dispersed in the adhesive system. In this regard, the present invention reacts poly 3-methylthiophene with 3-methylpyridine to obtain pretreated thiophene, which is then used to perform surface grafting modification on alumina to form a thiophene coating layer on the surface of alumina to obtain a filler. The thiophene coating layer improves the compatibility between alumina and epoxy resin, allowing the filler to be well dispersed in the adhesive system, thereby effectively improving the heat resistance and mechanical properties of the epoxy resin adhesive.

[0025] 2) The present invention prepares an auxiliary agent by condensing N2-(2-methoxyethyl)-2,5-pyridinediamine and monoethyl adipate. The auxiliary agent can be well dispersed in the adhesive system, promotes the formation of the network structure of the epoxy resin, and improves the toughness and water resistance of the epoxy resin adhesive. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below in conjunction with specific embodiments. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention but are not intended to limit the present invention.

[0027] Example 1

[0028] The epoxy resin adhesive for OLED is made of the following components in parts by weight: 143 parts of epoxy resin E-5, 1.8 parts of curing accelerator, 24 parts of curing agent, 23 parts of diluent, 0.7 parts of coupling agent, 22 parts of filler, and 4 parts of auxiliary agent. Among them, the curing accelerator is 2-ethyl-4-methylimidazole, the curing agent is tetrahydrophthalic anhydride, the diluent is composed of 1,6-hexanediol diglycidyl ether and propylene glycol methyl ether in a weight ratio of 3:2, and the coupling agent is 3-(glycidyloxypropyl)trimethoxysilane.

[0029] The filling is made by the following steps:

[0030] (1) mixing poly (3-methylthiophene), 3-methylpyridine and chloroform in a ratio of 1 mmol:1.2 mmol:30 mL, heating to 75° C. and reacting for 18 hours to obtain a reactant 1, washing the reactant 1 with anhydrous ethanol three times and drying at 75° C. for 12 hours to obtain a pretreated thiophene;

[0031] (2) The pretreated thiophene obtained in step (1) was mixed with alumina having an average particle size of 10 μm, ammonium persulfate, and N,N-dimethylformamide in a ratio of 18 mg:21 mg:10 mg:15 mL, and the mixture was stirred at room temperature for 12 hours to obtain reactant 2. The reactant 2 was washed three times with deionized water and then freeze-dried at -30°C for 12 hours to obtain a filler.

[0032] The additive is prepared by the following steps:

[0033] N2-(2-methoxyethyl)-2,5-pyridinediamine and monoethyl adipate are mixed, the pH value is adjusted to 4, and then heated to 165°C. After stirring for 10 minutes, triphenyl phosphite and sodium phosphite are added, and the weight ratio of N2-(2-methoxyethyl)-2,5-pyridinediamine, monoethyl adipate, triphenyl phosphite and sodium phosphite is 30:20:1:1. After heating to 185°C, the mixture is stirred and kept warm for 4 hours to obtain a reactant, and the reactant is filtered under reduced pressure to obtain a filter residue. The filter residue is washed 3 times with anhydrous ethanol and deionized water respectively, and then dried at 80°C for 12 hours to obtain an auxiliary agent.

[0034] The preparation method of Example 1 comprises the following steps:

[0035] S1. Weigh each component in parts by weight, mix the epoxy resin E51 with the diluent, and stir at 25 ° C and 300 rpm for 1.5 hours to obtain a mixture;

[0036] S2. The remaining components were mixed with the mixture obtained in step S1, and stirred at 25° C. and 200 rpm for 3.5 hours to obtain an epoxy resin adhesive for OLED.

[0037] Example 2

[0038] The epoxy resin adhesive for OLED is made of the following components in parts by weight: 44 parts of epoxy resin E-51, 1.9 parts of curing accelerator, 25 parts of curing agent, 24 parts of diluent, 0.8 parts of coupling agent, 23 parts of filler, and 4.5 parts of auxiliary agent. Among them, the curing accelerator is 2-ethyl-4-methylimidazole, the curing agent is tetrahydrophthalic anhydride, the diluent is composed of 1,6-hexanediol diglycidyl ether and propylene glycol methyl ether in a weight ratio of 3:2, and the coupling agent is 3-(glycidyloxypropyl)trimethoxysilane.

[0039] The filling is made by the following steps:

[0040] (1) mixing poly (3-methylthiophene), 3-methylpyridine and chloroform in a ratio of 1 mmol:1.2 mmol:30 mL, heating to 75° C. and reacting for 18 hours to obtain a reactant 1, washing the reactant 1 with anhydrous ethanol three times and drying at 75° C. for 12 hours to obtain a pretreated thiophene;

[0041] (2) The pretreated thiophene obtained in step (1) was mixed with alumina having an average particle size of 10 μm, ammonium persulfate, and N,N-dimethylformamide in a ratio of 18 mg:21 mg:10 mg:15 mL, and the mixture was stirred at room temperature for 12 hours to obtain reactant 2. The reactant 2 was washed three times with deionized water and then freeze-dried at -30°C for 12 hours to obtain a filler.

[0042] The additive is prepared by the following steps:

[0043] N2-(2-methoxyethyl)-2,5-pyridinediamine and monoethyl adipate are mixed, the pH value is adjusted to 4, and then heated to 165°C. After stirring for 10 minutes, triphenyl phosphite and sodium phosphite are added, and the weight ratio of N2-(2-methoxyethyl)-2,5-pyridinediamine, monoethyl adipate, triphenyl phosphite and sodium phosphite is 30:20:1:1. After heating to 185°C, the mixture is stirred and kept warm for 4 hours to obtain a reactant, and the reactant is filtered under reduced pressure to obtain a filter residue. The filter residue is washed 3 times with anhydrous ethanol and deionized water respectively, and then dried at 80°C for 12 hours to obtain an auxiliary agent.

[0044] The preparation method of Example 2 comprises the following steps:

[0045] S1. Weigh each component in parts by weight, mix the epoxy resin E51 with the diluent, and stir at 20 ° C and 400 rpm for 2 hours to obtain a mixture;

[0046] S2. The remaining components were mixed with the mixture obtained in step S1, and stirred at 20° C. and 300 rpm for 4 hours to obtain an epoxy resin adhesive for OLED.

[0047] Example 3

[0048] The epoxy resin adhesive for OLED is made of the following components in parts by weight: 140 parts of epoxy resin E-5, 1.5 parts of curing accelerator, 22 parts of curing agent, 20 parts of diluent, 0.5 parts of coupling agent, 20 parts of filler, and 3 parts of auxiliary agent. Among them, the curing accelerator is 2-ethyl-4-methylimidazole, the curing agent is tetrahydrophthalic anhydride, the diluent is composed of 1,6-hexanediol diglycidyl ether and propylene glycol methyl ether in a weight ratio of 3:2, and the coupling agent is 3-(glycidyloxypropyl)trimethoxysilane.

[0049] The filling is made by the following steps:

[0050] (1) mixing poly (3-methylthiophene), 3-methylpyridine and chloroform in a ratio of 1 mmol:1.2 mmol:30 mL, heating to 75° C. and reacting for 18 hours to obtain a reactant 1, washing the reactant 1 with anhydrous ethanol three times and drying at 75° C. for 12 hours to obtain a pretreated thiophene;

[0051] (2) The pretreated thiophene obtained in step (1) was mixed with alumina having an average particle size of 10 μm, ammonium persulfate, and N,N-dimethylformamide in a ratio of 18 mg:21 mg:10 mg:15 mL, and the mixture was stirred at room temperature for 12 hours to obtain reactant 2. The reactant 2 was washed three times with deionized water and then freeze-dried at -30°C for 12 hours to obtain a filler.

[0052] The additive is prepared by the following steps:

[0053] N2-(2-methoxyethyl)-2,5-pyridinediamine and monoethyl adipate are mixed, the pH value is adjusted to 4, and then heated to 165°C. After stirring for 10 minutes, triphenyl phosphite and sodium phosphite are added, and the weight ratio of N2-(2-methoxyethyl)-2,5-pyridinediamine, monoethyl adipate, triphenyl phosphite and sodium phosphite is 30:20:1:1. After heating to 185°C, the mixture is stirred and kept warm for 4 hours to obtain a reactant, and the reactant is filtered under reduced pressure to obtain a filter residue. The filter residue is washed 3 times with anhydrous ethanol and deionized water respectively, and then dried at 80°C for 12 hours to obtain an auxiliary agent.

[0054] The preparation method of Example 3 comprises the following steps:

[0055] S1. Weigh each component in parts by weight, mix the epoxy resin E51 with the diluent, and stir at 30 ° C and 300 rpm for 1 hour to obtain a mixture;

[0056] S2. The remaining components were mixed with the mixture obtained in step S1, and stirred at 30° C. and 200 rpm for 3 hours to obtain an epoxy resin adhesive for OLED.

[0057] Example 4

[0058] The epoxy resin adhesive for OLED is made of the following components in parts by weight: 45 parts of epoxy resin E-51, 2 parts of curing accelerator, 26 parts of curing agent, 25 parts of diluent, 1 part of coupling agent, 24 parts of filler, and 5 parts of auxiliary agent. Among them, the curing accelerator is 2-ethyl-4-methylimidazole, the curing agent is tetrahydrophthalic anhydride, the diluent is composed of 1,6-hexanediol diglycidyl ether and propylene glycol methyl ether in a weight ratio of 3:2, and the coupling agent is 3-(glycidyloxypropyl)trimethoxysilane.

[0059] The filling is made by the following steps:

[0060] (1) mixing poly (3-methylthiophene), 3-methylpyridine and chloroform in a ratio of 1 mmol:1.2 mmol:30 mL, heating to 75° C. and reacting for 18 hours to obtain a reactant 1, washing the reactant 1 with anhydrous ethanol three times and drying at 75° C. for 12 hours to obtain a pretreated thiophene;

[0061] (2) The pretreated thiophene obtained in step (1) was mixed with alumina having an average particle size of 10 μm, ammonium persulfate, and N,N-dimethylformamide in a ratio of 18 mg:21 mg:10 mg:15 mL, and the mixture was stirred at room temperature for 12 hours to obtain reactant 2. The reactant 2 was washed three times with deionized water and then freeze-dried at -30°C for 12 hours to obtain a filler.

[0062] The additive is prepared by the following steps:

[0063] N2-(2-methoxyethyl)-2,5-pyridinediamine and monoethyl adipate are mixed, the pH value is adjusted to 4, and then heated to 165°C. After stirring for 10 minutes, triphenyl phosphite and sodium phosphite are added, and the weight ratio of N2-(2-methoxyethyl)-2,5-pyridinediamine, monoethyl adipate, triphenyl phosphite and sodium phosphite is 30:20:1:1. After heating to 185°C, the mixture is stirred and kept warm for 4 hours to obtain a reactant, and the reactant is filtered under reduced pressure to obtain a filter residue. The filter residue is washed 3 times with anhydrous ethanol and deionized water respectively, and then dried at 80°C for 12 hours to obtain an auxiliary agent.

[0064] The preparation method of Example 4 comprises the following steps:

[0065] S1. Weigh each component in parts by weight, mix the epoxy resin E51 with the diluent, and stir at 25 ° C and 400 rpm for 1 hour to obtain a mixture;

[0066] S2. The remaining components were mixed with the mixture obtained in step S1, and stirred at 25° C. and 300 rpm for 3 hours to obtain an epoxy resin adhesive for OLED.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that the filler in the components is replaced by alumina with an average particle size of 10 μm without surface grafting modification, and the preparation step of the filler is omitted.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that no auxiliary agent is included in the components, and the preparation step of the auxiliary agent is omitted.

[0071] Experimental Example 1: Toughness Test

[0072] The epoxy resin adhesives prepared in Examples 1-4 and Comparative Example 2 were respectively placed in a polytetrafluoroethylene mold, and then the polytetrafluoroethylene mold was placed in an oven. After curing at 80 °C for 2 hours and then at 160 °C for 6 hours, the cured products were obtained. The fracture toughness values of the cured products were respectively tested using an electronic universal testing machine with reference to ASTM D5045-14 standard, and the testing speed was 10 mm / min.

[0073] The higher the fracture toughness value, the better the toughness. The test results are shown in Table 1:

[0074]

[0075] Table 1

[0076] As can be seen from Table 1, the fracture toughness values of Examples 1-4 of the present invention are all relatively high, indicating that the epoxy resin adhesive prepared by the present invention has good toughness. Some components and preparation steps used in Comparative Example 2 are different from those in Example 1. Compared with Example 1, the fracture toughness value of Comparative Example 2 decreased significantly, indicating that the additives prepared by the present invention can effectively improve the toughness of the epoxy resin adhesive.

[0077] Experimental Example Two: Heat Resistance Test

[0078] The epoxy resin adhesives prepared in Examples 1-4 and Comparative Example 1 were respectively placed in a polytetrafluoroethylene mold, and then the polytetrafluoroethylene mold was placed in an oven. After curing at 80 °C for 2 hours and then at 160 °C for 6 hours, the cured products were obtained. The thermal decomposition temperature of the cured products at 5% weight loss was respectively tested using a thermogravimetric analyzer. The test atmosphere was nitrogen, the test temperature range was 50-800 °C, and the heating rate was 10 °C / min.

[0079] The higher the thermal decomposition temperature, the better the heat resistance. The test results are shown in Table 2:

[0080]

[0081] Table 2

[0082] As can be seen from Table 2, the thermal decomposition temperatures of Examples 1-4 of the present invention are all relatively high, indicating that the epoxy resin adhesive prepared by the present invention has good heat resistance. Some components and preparation steps used in Comparative Example 1 are different from those in Example 1. Compared with Example 1, the thermal decomposition temperature of Comparative Example 1 decreased, indicating that compared with alumina without surface graft modification, the filler prepared by the present invention has a better effect on improving the heat resistance of the epoxy resin adhesive.

[0083] Experimental Example Three: Water Resistance Test

[0084] The epoxy resin adhesives prepared in Examples 1-4 and Comparative Example 2 were uniformly coated on a glass substrate, respectively. The glass substrate was then placed in an oven and cured at 80° C. for 2 hours and then at 160° C. for 6 hours to obtain a cured product. The water vapor permeability of the cured product was tested using a water vapor permeability tester at 40° C. and 100% relative humidity for 24 hours.

[0085] The lower the water vapor transmission rate, the better the water resistance. The test results are shown in Table 3:

[0086]

[0087] Table 3

[0088] As can be seen from Table 3, the water vapor permeability of Examples 1-4 of the present invention is relatively low, indicating that the epoxy resin adhesive prepared by the present invention has good water resistance. Some components and preparation steps used in Comparative Example 2 are different from those in Example 1. Compared with Example 1, the water vapor permeability of Comparative Example 2 is significantly increased, indicating that the auxiliary agent prepared by the present invention can effectively improve the water resistance of the epoxy resin adhesive.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An epoxy resin adhesive for OLED, characterized in that: The invention is prepared from the following components in parts by weight: 40-45 parts of epoxy resin E-51, 1.5-2 parts of curing accelerator, 22-26 parts of curing agent, 20-25 parts of diluent, 0.5-1 parts of coupling agent, 20-24 parts of filler and 3-5 parts of auxiliary agent.

2. The epoxy resin adhesive for OLED according to claim 1, characterized in that: The curing accelerator is 2-ethyl-4-methylimidazole, and the curing agent is tetrahydrophthalic anhydride.

3. The epoxy resin adhesive for OLED according to claim 1, characterized in that: The diluent consists of 1,6-hexanediol diglycidyl ether and propylene glycol methyl ether in a weight ratio of 3:

2.

4. The epoxy resin adhesive for OLED according to claim 1, characterized in that: The coupling agent is 3-(glycidyloxypropyl)trimethoxysilane.

5. The epoxy resin adhesive for OLED according to claim 1, characterized in that: The filler is prepared by the following steps: (1) Poly (3-methylthiophene), 3-methylpyridine and chloroform are mixed, heated to 75° C. and reacted for 18 hours to obtain a reactant 1, and the reactant 1 is washed with anhydrous ethanol for three times and then dried to obtain a pretreated thiophene; (2) The pretreated thiophene obtained in step (1), aluminum oxide, ammonium persulfate, and N,N-dimethylformamide were mixed, and the mixture was stirred at room temperature for 12 hours to obtain a reactant 2, and the reactant 2 was washed three times with deionized water and freeze-dried to obtain a filler.

6. The epoxy resin adhesive for OLED according to claim 5, characterized in that: In the preparation step (1) of the filler, the ratio of poly 3-methylthiophene, 3-methylpyridine and chloroform is 1 mmol:1.2 mmol:30 mL, the drying temperature is 75° C., and the drying time is 12 hours. In the step (2), the average particle size of alumina is 10 μm, the ratio of pretreated thiophene obtained in the step (1), alumina, ammonium persulfate and N,N-dimethylformamide is 18 mg:21 mg:10 mg:15 mL, the freeze-drying temperature is -30° C., and the freeze-drying time is 12 hours.

7. The epoxy resin adhesive for OLED according to claim 1, characterized in that: The auxiliary agent is prepared by the following steps: N2-(2-methoxyethyl)-2,5-pyridinediamine and monoethyl adipate were mixed, the pH value was adjusted to 4, and then heated to 165°C. After stirring for 10 minutes, triphenyl phosphite and sodium phosphite were added, and the mixture was heated to 185°C and stirred for 4 hours to obtain a reactant. The reactant was filtered under reduced pressure to obtain a filter residue. The filter residue was washed 3 times with anhydrous ethanol and deionized water respectively, and then dried to obtain an auxiliary agent.

8. The epoxy resin adhesive for OLED according to claim 7, characterized in that: In the preparation step of the auxiliary agent, the weight ratio of N2-(2-methoxyethyl)-2,5-pyridinediamine, monoethyl adipate, triphenyl phosphite and sodium phosphite is 30:20:1:1, the drying temperature is 80° C., and the drying time is 12 hours.

9. The method for preparing an epoxy resin adhesive for OLED according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1 weighed each component in parts by weight, the epoxy resin E51 and the diluent were mixed and stirred for 1-2 hours to obtain a mixture; S2. Mix the remaining components with the mixture obtained in step S1, and stir for 3-4 hours to obtain an epoxy resin adhesive for OLED.

10. The method for preparing an epoxy resin adhesive for OLED according to claim 9, characterized in that: In the step S1, the stirring temperature is 20-30°C, and the stirring speed is 300-400rpm; in the step S2, the stirring temperature is 20-30°C, and the stirring speed is 200-300rpm.

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