Epoxy adhesive for bonding pa6 and pp films and method of making same

Abstract

The application discloses an epoxy adhesive which can be used for bonding PA6 and PP films and a preparation method thereof. The epoxy adhesive is internally introduced with a polar group amide bond, and a strong bonding strength between the epoxy adhesive and PA material is generated through intermolecular force (hydrogen bond). The epoxy adhesive not only improves the wettability of the adhesive matrix to the PA polar material, but also forms a large number of hydrogen bonds between the adhesive and the PA polar material, so that the bonding strength is enhanced. Meanwhile, the epoxy adhesive itself is non-polar, and the non-polar group has good compatibility with polypropylene in the curing process, so that the epoxy adhesive is well bonded to the PP film through molecular chain entanglement. The epoxy adhesive can significantly improve the bonding strength between the PA6 and the PP film, and further improve the performance of the composite film.

Description

Technical Field

[0001] This invention relates to the field of adhesives for polymer materials, and in particular to an epoxy adhesive and its preparation method, as well as its application in bonding PA6 and PP films. Background Technology

[0002] The application of polymer materials in agriculture, industry, and other fields is becoming increasingly widespread. Especially with today's highly developed logistics, polymer packaging materials have become a hot area. To achieve good packaging performance, it is necessary to combine multiple polymer films, or polymers with metal films, to endow polymers with excellent properties such as puncture resistance, barrier properties, and high strength. The composite of multilayer films relies heavily on adhesives, especially when two films with significantly different polarities are combined. Good adhesion cannot be achieved solely through the polymer's own adhesion at high temperatures, and an additional adhesive coating is usually required.

[0003] Polypropylene (PP) is a high-performance thermoplastic synthetic resin with excellent chemical resistance, heat resistance, electrical insulation, and good abrasion resistance. It is resistant to corrosion from acids, alkalis, salt solutions, and various organic solvents below 80℃, and is widely used in the production of fiber products, medical devices, and chemical containers. However, the mechanical strength and high-temperature heat resistance of polypropylene cannot meet the requirements of industrial applications. Therefore, other materials are needed to supplement the properties of polypropylene to meet industrial needs.

[0004] Polyamide (PA) was the first thermoplastic to develop that could withstand heavy loads, and it is also the most produced, diverse, and widely used of the five major general-purpose engineering plastics. PA materials exhibit excellent heat resistance, low-temperature resistance, impact resistance, good chemical stability, and fatigue resistance, making polyamide a crucial component in packaging materials, especially industrial packaging. In packaging materials, polyamide primarily enhances the mechanical properties and heat resistance of films, effectively expanding the application range and service life of packaging materials.

[0005] Therefore, PP film is laminated with PA to prepare packaging bags with high mechanical strength, heat resistance, solvent resistance, and electrical insulation. However, the polarity of PP and PA materials differs significantly, resulting in poor adhesion between them, which greatly affects the performance and service life of the composite packaging bags. Therefore, adhesives are usually used to bond PA and PP films. Epoxy adhesives are currently the most widely used adhesives in the world. Epoxy resin is a thermosetting resin with good bonding strength, chemical resistance, and electrical insulation, and its processing technology is also very flexible.

[0006] This project provides a novel epoxy adhesive that can be used to bond PA6 and PP films, greatly improving the bond strength between PA6 and PP films and giving the composite packaging bag excellent mechanical properties and service life. Summary of the Invention

[0007] This invention provides an epoxy adhesive, its preparation method, and its application. The epoxy adhesive of this invention can improve the bonding strength between PA6 and PP films, thereby improving the performance of the composite film.

[0008] The technical solution of the present invention is as follows:

[0009] An epoxy adhesive, named N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide, has the following structural formula:

[0010]

[0011] The preparation method of the epoxy adhesive of the present invention includes the following steps:

[0012] (1) Dissolve p-aminophenol and triethylamine in N,N-dimethylformamide to obtain a p-aminophenol-triethylamine mixed solution; dissolve adipic acid chloride in N,N-dimethylformamide to obtain an adipic acid chloride solution; add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution, stir and react at 0-25℃ (preferably 15℃) for 20 min-1 h (preferably 30 min), then filter, collect the filtrate and remove the solvent by rotary evaporation to obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide;

[0013] The molar ratio of p-aminophenol, adipic acid chloride, and triethylamine is 1:0.4:0.9 to 1:0.6:1.1, preferably 1:0.51:1.01;

[0014] During the reaction, the rotor stirring speed is 200-500 rpm, preferably 300 rpm;

[0015] The reaction formula is as follows:

[0016]

[0017] (2) The N,N-bis(4-hydroxyphenyl)hexadiamide obtained in step (1) is mixed with epichlorohydrin and tetrabutylammonium bromide is added. The mixture is stirred at 70-100℃ (preferably 80℃) for 2.5-4h (preferably 3h) to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexadiamide. No post-treatment is required, and the mixture can be used directly in the next step of the reaction.

[0018] The molar ratio of N,N-bis(4-hydroxyphenyl)hexadiamide to epichlorohydrin is 1:6 to 1:14, preferably 1:10;

[0019] The mass ratio of N,N-bis(4-hydroxyphenyl)hexamethylenediamide to tetrabutylammonium bromide is 1:0.1 to 1:0.4, preferably 1:0.3;

[0020] During the reaction, the stirring speed is 200-350 rpm, preferably 300 rpm;

[0021] The reaction formula is as follows:

[0022]

[0023] (3) Add an aqueous sodium hydroxide solution to the mixture of N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide in step (2), and stir the mixture at 50-80°C (preferably 60°C) for 2.5-4 hours (preferably 3 hours). After post-treatment, the epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide is obtained.

[0024] The molar ratio of N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide to sodium hydroxide is 1:2 to 1:5, preferably 1:3;

[0025] The mass fraction of the sodium hydroxide aqueous solution is 3-7%, preferably 5%;

[0026] During the reaction, the stirring speed is 200-350 rpm, preferably 300 rpm;

[0027] The post-processing method is as follows: After the reaction is completed, wait for the reaction solution to cool to room temperature, add a mixture of deionized water and epichlorohydrin in a volume ratio of 1:0.8 to 1:2, stir and wash, filter, extract the filtrate with toluene, wash the extract with deionized water, remove the solvent by rotary evaporation and dry to obtain the product epoxy binder.

[0028] The reaction formula is as follows:

[0029]

[0030] The epoxy adhesive described in this invention can be used for bonding PA6 films and PP films. The specific application method is as follows:

[0031] The epoxy adhesive of the present invention is mixed evenly with bisphenol A type diglycidyl ether with an epoxy value of 0.51 mol / 100g, and then diethylenetriamine is added as a curing agent to obtain a mixed adhesive. The obtained mixed adhesive is evenly coated on the film to bond the PP film and the PA6 film. Then it is placed in a hot press at 110°C and pressurized at 2MPa for 3min to obtain a PP / PA composite film.

[0032] The preferred molar ratio of epoxy adhesive to bisphenol A diglycidyl ether is 1:5.5;

[0033] The preferred molar ratio of the curing agent diethylenetriamine to the epoxy groups in the mixed binder is 1:2;

[0034] After coating and tableting, the preferred adhesive layer thickness is 0.08 mm.

[0035] The advantages of this invention are:

[0036] This invention synthesizes a novel epoxy adhesive with amide bonds. Based on traditional non-polar epoxy resin, a polar group—amide bond—is introduced into the molecule, which enables the epoxy adhesive to generate strong adhesion to PA materials through intermolecular forces (hydrogen bonds).

[0037] This invention not only improves the wettability of the adhesive matrix to polar PA materials, but also enables the formation of numerous hydrogen bonds between the adhesive and polar materials such as PA, thereby enhancing adhesion. Simultaneously, the epoxy adhesive itself is non-polar, and during the curing process, the non-polar groups exhibit good compatibility with polypropylene, achieving excellent adhesion to the PP film through molecular chain entanglement.

[0038] In summary, the epoxy adhesive provided by this invention can significantly improve the bonding strength between PA6 and PP film. Detailed Implementation

[0039] The present invention is further described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0040] Example 1

[0041] Preparation of epoxy adhesive:

[0042] (1) Dissolve 8.72 g of p-aminophenol and 7.32 g of adipic acid chloride in 100 mL of N,N-dimethylformamide, respectively. Add 8.08 g of triethylamine to the p-aminophenol-N,N-dimethylformamide solution and stir until homogeneous. Slowly add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution and stir slowly at 15 °C for 30 min. Filter to obtain the filtrate, remove excess solvent by rotary evaporation, and obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide.

[0043] (2) 13.12 g of N,N-bis(4-hydroxyphenyl)hexamethylenediamide prepared in step (1) was added to 31 mL of epichlorohydrin and then transferred to a three-necked flask for reaction. 1.50 g of tetrabutylammonium bromide was added to the mixed solution, and the mixture was reacted at 100 °C for 3 h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment was required, and the mixture was used directly for the next reaction.

[0044] (3) Add 7g of 5% sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), cool to 80℃ and react for 3h, stir, filter, extract, wash and dry to finally obtain 10.21g of epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide.

[0045] Applications of epoxy adhesives for bonding PA6 and PP films:

[0046] 0.10 g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.90 g of bisphenol A diglycidyl ether with an epoxy value of 0.51 mol / 100 g were mixed evenly, and then 0.12 g of diethylenetriamine was added as a curing agent to prepare an adhesive. 200 mm * 150 mm PP and PA6 films were cut, with a 50 mm * 150 mm area at one end designated as a blank area. 1.12 g of adhesive was evenly applied to the other 150 mm * 150 mm area. The PP and PA films were then bonded together and placed in a hot press at 110°C, pressurized at 2 MPa for 3 minutes to obtain a PP / PA composite film.

[0047] Example 2

[0048] Preparation of epoxy adhesive:

[0049] (1) Dissolve 8.72 g of p-aminophenol and 7.32 g of adipic acid chloride in 100 mL of N,N-dimethylformamide, respectively. Add 8.08 g of triethylamine to the p-aminophenol-N,N-dimethylformamide solution and stir until homogeneous. Slowly add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution and stir slowly at 15 °C for 30 min. Filter to obtain the filtrate, remove excess solvent by rotary evaporation, and obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide.

[0050] (2) 12.85 g of N,N-bis(4-hydroxyphenyl)hexamethylenediamide prepared in step (1) was added to 31 mL of epichlorohydrin and then transferred to a three-necked flask for reaction. 1.50 g of tetrabutylammonium bromide was added to the mixed solution, and the mixture was reacted at 90 °C for 3 h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment was required, and the mixture was used directly for the next reaction.

[0051] (3) Add 7g of 5% sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), cool to 70℃ and react for 3h, stir, filter, extract, wash and dry to finally obtain 12.32g of epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide.

[0052] Applications of epoxy adhesives for bonding PA6 and PP films:

[0053] 0.10 g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.90 g of bisphenol A diglycidyl ether with an epoxy value of 0.51 mol / 100 g were mixed evenly, and then 0.12 g of diethylenetriamine was added as a curing agent to prepare an adhesive. 200 mm * 150 mm PP and PA6 films were cut, with a 50 mm * 150 mm area at one end designated as a blank area. 1.12 g of adhesive was evenly applied to the other 150 mm * 150 mm area. The PP and PA films were then bonded together and placed in a hot press at 110°C, pressurized at 2 MPa for 3 minutes to obtain a PP / PA composite film.

[0054] Example 3

[0055] Preparation of epoxy adhesive:

[0056] (1) Dissolve 8.72 g of p-aminophenol and 7.32 g of adipic acid chloride in 100 mL of N,N-dimethylformamide, respectively. Add 8.08 g of triethylamine to the p-aminophenol-N,N-dimethylformamide solution and stir until homogeneous. Slowly add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution and stir slowly at 15 °C for 30 min. Filter to obtain the filtrate, remove excess solvent by rotary evaporation, and obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide.

[0057] (2) 13.02 g of N,N-bis(4-hydroxyphenyl)hexamethylenediamide prepared in step (1) was added to 31 mL of epichlorohydrin and then transferred to a three-necked flask for reaction. 1.50 g of tetrabutylammonium bromide was added to the mixed solution, and the mixture was reacted at 80 °C for 3 h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment was required, and the mixed system was directly used for the next reaction.

[0058] (3) Add 7g of 5% sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), cool to 60℃ and react for 3h, stir, filter, extract, wash and dry to finally obtain 15.11g of epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide.

[0059] Applications of epoxy adhesives for bonding PA6 and PP films:

[0060] 0.10 g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.90 g of bisphenol A diglycidyl ether with an epoxy value of 0.51 mol / 100 g were mixed evenly, and then 0.12 g of diethylenetriamine was added as a curing agent to prepare an adhesive. 200 mm * 150 mm PP and PA6 films were cut, with a 50 mm * 150 mm area at one end designated as a blank area. 1.12 g of adhesive was evenly applied to the other 150 mm * 150 mm area. The PP and PA films were then bonded together and placed in a hot press at 110°C, pressurized at 2 MPa for 3 minutes to obtain a PP / PA composite film.

[0061] Example 4

[0062] Preparation of epoxy adhesive:

[0063] (1) Dissolve 8.72 g of p-aminophenol and 7.32 g of adipic acid chloride in 100 mL of N,N-dimethylformamide, respectively. Add 8.08 g of triethylamine to the p-aminophenol-N,N-dimethylformamide solution and stir until homogeneous. Slowly add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution and stir slowly at 15 °C for 30 min. Filter to obtain the filtrate, remove excess solvent by rotary evaporation, and obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide.

[0064] (2) 12.95 g of N,N-bis(4-hydroxyphenyl)hexamethylenediamide prepared in step (1) was added to 31 mL of epichlorohydrin and then transferred to a three-necked flask for reaction. 1.50 g of tetrabutylammonium bromide was added to the mixed solution, and the mixture was reacted at 80 °C for 3 h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment was required, and the mixture was used directly for the next reaction.

[0065] (3) Add 7g of 5% sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), cool to 60℃ and react for 3h, stir, filter, extract, wash and dry to finally obtain 14.63g of epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide.

[0066] Applications of epoxy adhesives for bonding PA6 and PP films:

[0067] 0.20 g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.80 g of bisphenol A diglycidyl ether with an epoxy value of 0.51 mol / 100 g were mixed evenly, and then 0.12 g of diethylenetriamine was added as a curing agent to prepare an adhesive. 200 mm * 150 mm PP and PA6 films were cut, with a 50 mm * 150 mm area at one end designated as a blank area. 1.12 g of adhesive was evenly applied to the other 150 mm * 150 mm area. The PP and PA films were then bonded together and placed in a hot press at 110°C under 2 MPa pressure for 3 minutes to obtain a PP / PA composite film.

[0068] Example 5

[0069] Preparation of epoxy adhesive:

[0070] (1) Dissolve 8.72 g of p-aminophenol and 7.32 g of adipic acid chloride in 100 mL of N,N-dimethylformamide, respectively. Add 8.08 g of triethylamine to the p-aminophenol-N,N-dimethylformamide solution and stir until homogeneous. Slowly add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution and stir slowly at 15 °C for 30 min. Filter to obtain the filtrate, remove excess solvent by rotary evaporation, and obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide.

[0071] (2) 12.56 g of N,N-bis(4-hydroxyphenyl)hexamethylenediamide prepared in step (1) was added to 31 mL of epichlorohydrin and then transferred to a three-necked flask for reaction. 1.50 g of tetrabutylammonium bromide was added to the mixed solution, and the mixture was reacted at 80 °C for 3 h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment was required, and the mixture was used directly for the next reaction.

[0072] (3) Add 7g of 5% sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), cool to 60℃ and react for 3h, stir, filter, extract, wash and dry to finally obtain 14.46g of epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide.

[0073] Applications of epoxy adhesives for bonding PA6 and PP films:

[0074] 0.40g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.60g of bisphenol A diglycidyl ether with an epoxy value of 0.51mol / 100g were mixed evenly, and then 0.12g of diethylenetriamine was added as a curing agent to prepare an adhesive. 200mm*150mm PP and PA6 films were cut, with a 50mm*150mm area at one end designated as a blank area. 1.12g of adhesive was evenly applied to the other 150mm*150mm area. The PP and PA films were then bonded together and placed in a hot press at 110℃, pressurized at 2MPa for 3 minutes to obtain a PP / PA composite film.

[0075] Example 6

[0076] Preparation of epoxy adhesive:

[0077] (1) Dissolve 8.72 g of p-aminophenol and 7.32 g of adipic acid chloride in 100 mL of N,N-dimethylformamide, respectively. Add 8.08 g of triethylamine to the p-aminophenol-N,N-dimethylformamide solution and stir until homogeneous. Slowly add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution and stir slowly at 15 °C for 30 min. Filter to obtain the filtrate, remove excess solvent by rotary evaporation, and obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide.

[0078] (2) Add 13.01 g of N,N-bis(4-hydroxyphenyl)hexamethylenediamide prepared in step (1) to 31 mL of epichlorohydrin, and then transfer the mixture to a three-necked flask for reaction. Add 1.50 g of tetrabutylammonium bromide to the mixed solution and react at 80 °C for 3 h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment is required, and the mixed system can be used directly for the next reaction.

[0079] (3) Add 7g of 5% sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), cool to 60℃ and react for 3h, stir, filter, extract, wash and dry to finally obtain 15.03g of epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide.

[0080] Applications of epoxy adhesives for bonding PA6 and PP films:

[0081] 0.60g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.40g of bisphenol A diglycidyl ether with an epoxy value of 0.51mol / 100g were mixed evenly, and then 0.12g of diethylenetriamine was added as a curing agent to prepare an adhesive. 200mm*150mm PP and PA6 films were cut, with a 50mm*150mm area at one end designated as a blank area. 1.12g of adhesive was evenly applied to the other 150mm*150mm area. The PP and PA films were then bonded together and placed in a hot press at 110℃, pressurized at 2MPa for 3 minutes to obtain a PP / PA composite film.

[0082] Example 7

[0083] Preparation of epoxy adhesive:

[0084] (1) Dissolve 8.72 g of p-aminophenol and 7.32 g of adipic acid chloride in 100 mL of N,N-dimethylformamide, respectively. Add 8.08 g of triethylamine to the p-aminophenol-N,N-dimethylformamide solution and stir until homogeneous. Slowly add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution and stir slowly at 15 °C for 30 min. Filter to obtain the filtrate, remove excess solvent by rotary evaporation, and obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide.

[0085] (2) 12.72 g of N,N-bis(4-hydroxyphenyl)hexamethylenediamide prepared in step (1) was added to 31 mL of epichlorohydrin and then transferred to a three-necked flask for reaction. 1.50 g of tetrabutylammonium bromide was added to the mixed solution, and the mixture was reacted at 80 °C for 3 h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment was required, and the mixture was used directly for the next reaction.

[0086] (3) Add 7g of 5% sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), cool to 60℃ and react for 3h, stir, filter, extract, wash and dry to finally obtain 14.71g of epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide.

[0087] Applications of epoxy adhesives for bonding PA6 and PP films:

[0088] 0.80g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.20g of bisphenol A diglycidyl ether with an epoxy value of 0.51mol / 100g were mixed evenly, and then 0.12g of diethylenetriamine was added as a curing agent to prepare an adhesive. 200mm*150mm PP and PA6 films were cut, with a 50mm*150mm area at one end designated as a blank area. 1.12g of adhesive was evenly applied to the other 150mm*150mm area. The PP and PA films were then bonded together and placed in a hot press at 110℃, pressurized at 2MPa for 3 minutes to obtain a PP / PA composite film.

[0089] Comparative Example 1

[0090] 1.00g of N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide and 0.12g of diethylenetriamine were mixed evenly to prepare an adhesive. PP and PA6 films of 200mm*150mm were cut, with a 50mm*150mm area at one end designated as a blank area. 1.12g of adhesive was evenly applied to the other 150mm*150mm area. The PP and PA films were then bonded together and placed in a hot press at 110℃, pressurized at 2MPa for 3 minutes to obtain a PP / PA composite film.

[0091] Comparative Example 2

[0092] 1.00g of bisphenol A diglycidyl ether with an epoxy value of 0.51mol / 100g was mixed evenly with 0.12g of diethylenetriamine to prepare an adhesive. PP and PA6 films of 200mm*150mm were cut, with a 50mm*150mm area at one end designated as a blank area. 1.12g of adhesive was evenly applied to the other 150mm*150mm area. The PP and PA films were then bonded together and placed in a hot press at 110℃, pressurized at 2MPa for 3 minutes to obtain a PP / PA composite film.

[0093] Example Performance Test Results

[0094] Performance testing: The peel strength of the composite materials prepared in the examples and comparative examples was tested in accordance with GB / T 2791-1995 Adhesives T Peel Strength Test Method Flexible Materials to Flexible Materials. The results are shown in Table 1.

[0095] Table 1. Performance test results of PA / PP composites bonded with adhesive.

[0096]

Claims

1. The application of an epoxy adhesive in the bonding of PA6 film and PP film; Epoxy adhesive name: N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide, structural formula shown below: The application method is as follows: The epoxy adhesive was mixed evenly with bisphenol A type diglycidyl ether with an epoxy value of 0.51 mol / 100 g, and then diethylenetriamine was added as a curing agent to obtain a mixed adhesive. The obtained mixed adhesive was evenly coated on the film to bond the PP film and the PA6 film. Then, it was placed in a hot press at 110 ℃ and pressurized at 2 MPa for 3 min to obtain a PP / PA6 composite film.

2. The application as described in claim 1, characterized in that, The preparation method of epoxy adhesive includes the following steps: (1) Dissolve p-aminophenol and triethylamine in N,N-dimethylformamide to obtain a p-aminophenol-triethylamine mixed solution; dissolve adipic acid chloride in N,N-dimethylformamide to obtain an adipic acid chloride solution; add the adipic acid chloride solution dropwise to the p-aminophenol-triethylamine mixed solution, stir and react at 0~25℃ for 20min~1h, then filter, collect the filtrate and remove the solvent by rotary evaporation to obtain N,N-bis(4-hydroxyphenyl)hexamethylenediamide; The reaction formula is as follows: (2) The N,N-bis(4-hydroxyphenyl)hexamethylenediamide obtained in step (1) is mixed with epichlorohydrin and tetrabutylammonium bromide is added. The mixture is stirred at 70~100℃ for 2.5~4h to obtain N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide. No post-treatment is required, and the mixture can be used directly in the next step of the reaction. The reaction formula is as follows: (3) Add sodium hydroxide aqueous solution to the N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide mixture in step (2), stir and react at 50~80℃ for 2.5~4h, and then after post-treatment, obtain epoxy binder N,N-bis(4-(ethylene oxide-2-methoxy)phenyl)hexamethylenediamide; The reaction formula is as follows: 。 3. The application as described in claim 2, characterized in that, In step (1) of the preparation method of epoxy adhesive, the molar ratio of p-aminophenol, adipic acid chloride and triethylamine is 1:0.4:0.9~1:0.6:1.

1.

4. The application as described in claim 2, characterized in that, In step (2) of the preparation method of epoxy adhesive, the molar ratio of N,N-bis(4-hydroxyphenyl)hexamethylenediamide and epichlorohydrin is 1:6 to 1:

14.

5. The application as described in claim 2, characterized in that, In step (2) of the preparation method of epoxy adhesive, the mass ratio of N,N-bis(4-hydroxyphenyl)hexamethylenediamide and tetrabutylammonium bromide is 1:0.1~1:0.

4.

6. The application as described in claim 2, characterized in that, In step (3) of the preparation method of epoxy adhesive, the molar ratio of N,N-bis(4-(2-chloro-2-hydroxyethoxy)phenyl)hexamethylenediamide and sodium hydroxide is 1:2 to 1:

5.

7. The application as described in claim 2, characterized in that, In step (3) of the preparation method of epoxy adhesive, the mass fraction of sodium hydroxide aqueous solution is 3~7%.

8. The application as described in claim 2, characterized in that, In step (3) of the preparation method of epoxy adhesive, the post-treatment method is as follows: After the reaction is completed, wait for the reaction solution to cool to room temperature, add a mixture of deionized water and epichlorohydrin in a volume ratio of 1:0.8~1:2, stir and wash, filter, extract the filtrate with toluene, wash the extract with deionized water, remove the solvent by rotary evaporation and dry to obtain the product epoxy adhesive.

9. The application as described in claim 1, characterized in that, The molar ratio of epoxy adhesive to bisphenol A diglycidyl ether is 1:5.5; The molar ratio of the curing agent diethylenetriamine to the epoxy groups in the mixed adhesive is 1:2; After coating and tableting, the adhesive layer thickness is 0.08 mm.

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