Water-based pressure-sensitive adhesive for bonding high-transparency strong-stripping PET and preparation method of water-based pressure-sensitive adhesive

Abstract

The invention discloses a high-transparency strong-stripping water-based pressure-sensitive adhesive for PET bonding and a preparation method thereof, and the method comprises the following steps: adding a brominated aminopyridine monomer, a hydroxyl-terminated diol monomer and a strong alkali substance into ethyl acetate according to parts by mass, uniformly stirring, heating the system to 50-70 DEG C, reacting for 2-4 hours, and removing a solvent after the reaction is finished to obtain a modified amine cross-linking agent. The preparation method comprises the following steps: uniformly stirring deionized water, 2-ethylhexyl acrylate, n-butyl acrylate, methyl methacrylate, glycidyl methacrylate, sodium dodecyl benzene sulfonate, a TX-10 surfactant and ammonium persulfate in parts by mass to obtain a pre-emulsion; heating the pre-emulsion step by step, after the whole reaction is finished and the temperature of the system is reduced to room temperature, adding a modified amine cross-linking agent into the system, and uniformly stirring. Through synthesis of the modified amine cross-linking agent and cooperative use of the modified amine cross-linking agent and the glycidyl methacrylate pressure-sensitive adhesive system, the bonding strength of the water-based pressure-sensitive adhesive to a PET film material can be greatly improved, and good light transmittance is achieved.

Description

Technical Field

[0001] This invention relates to a water-based pressure-sensitive adhesive for bonding high-transparency, high-peel strength PET and its preparation method. Background Technology

[0002] The preparation of waterborne pressure-sensitive adhesive (PSAs) systems based on emulsion polymerization is one of the important development directions for adhesives. Compared with conventional oil-based PSAs, waterborne PSAs significantly reduce VOC emissions while maintaining certain adhesive properties, making them widely used in civilian applications. Furthermore, the synthesis process of waterborne PSAs is more controllable, with stable overall heat release, good experimental repeatability, and stable product performance. These superior properties have led to the gradual replacement of oil-based PSAs as the mainstream PSAs in the market.

[0003] However, water-based pressure-sensitive adhesive systems consistently fail to achieve the same level of light transmittance and bonding strength as oil-based adhesive systems during membrane bonding. This is primarily because water, the solvent in water-based pressure-sensitive adhesive systems, cannot effectively corrode or wet the membrane material. Once the water evaporates, the adhesive chain segments tend to become fixed and cannot further wet the substrate, resulting in poor bonding strength. Furthermore, poor mobility hinders the formation of a uniform surface layer. Therefore, water-based pressure-sensitive adhesive systems exhibit low bonding strength and a significant decrease in light transmittance during membrane bonding. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of insufficient film strength and poor light transmittance of water-based pressure-sensitive adhesive systems, and to provide a high-transmittance and high-strength peelable water-based pressure-sensitive adhesive for PET bonding and its preparation method. The preparation method uses a modified amine crosslinking agent with a special chemical structure and prepares it through an etherification reaction. This modified amine crosslinking agent can increase the toughness and light transmittance of the water-based pressure-sensitive adhesive.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a high-transparency, high-peel strength water-based pressure-sensitive adhesive for bonding PET, the method being as follows:

[0007] Step 1: Weigh out 10-50 parts by weight of bromoaminopyridine monomer, 70-200 parts by weight of terminal hydroxyl diol monomer, 10-35 parts by weight of strong base substance, and 200-500 parts by weight of ethyl acetate.

[0008] Step 2: Add bromoaminopyridine monomer, terminal hydroxyl diol monomer and strong base to ethyl acetate, stir at 20~150 rpm for 15~30 min, after stirring, raise the system temperature to 50~70℃ and react for 2~4 h, after the reaction is completed, remove ethyl acetate to obtain modified amine crosslinking agent;

[0009] Step 3: Weigh out 200-400 parts of deionized water, 70-150 parts of isooctyl acrylate, 50-100 parts of n-butyl acrylate, 30-70 parts of methyl methacrylate, 2-6 parts of glycidyl methacrylate, 2-4 parts of sodium dodecylbenzene sulfonate, 6-10 parts of TX-10 surfactant, and 0.3-0.9 parts of initiator according to the following weight proportions:

[0010] Step 4: Add all the substances from Step 3 to a four-necked flask and stir at a speed of 30-150 rpm for 15-30 minutes to obtain a pre-emulsion.

[0011] Step 5: Weigh 100-300 parts of the pre-emulsion and heat it to 80℃-85℃. Stir at 50-150 rpm for 2-4 hours. Then, add 200-400 parts of the pre-emulsion dropwise to the system for 1-1.5 hours. After the addition is complete, continue the reaction for 1-2 hours. Adding the pre-emulsion separately staggers the exothermic peaks of the reaction heat, ensuring a more stable temperature throughout the system and improving the adhesion and optical properties of the polymer.

[0012] Step 6: After the entire reaction is complete and the system temperature drops to room temperature, add 1-4 parts of modified amine crosslinking agent to the system, stir for 20-40 minutes, and obtain a high-permeability, high-strength peel PET adhesive water-based pressure-sensitive adhesive.

[0013] Further, in step one, the bromoaminopyridine monomer is one of 2-bromo-6-aminopyridine, 2-bromo-4-aminopyridine, or 4-bromo-2,6-diaminopyridine.

[0014] Furthermore, in step one, the terminal hydroxyl diol monomer is one of polyethylene glycol, polypropylene glycol, or polytetrahydrofuran.

[0015] Furthermore, in step one, the strong alkali substance is one of potassium hydroxide, sodium hydroxide, or calcium hydroxide.

[0016] Furthermore, in step two, the initiator is ammonium persulfate and potassium persulfate.

[0017] A high-permeability, high-peelability water-based pressure-sensitive adhesive for bonding PET prepared by the above preparation method.

[0018] The advantages of this invention compared to existing technologies are as follows: This invention aims to design and propose a high-transmittance, high-peel strength water-based pressure-sensitive adhesive for PET bonding, and its preparation method, while maintaining the excellent performance of the water-based pressure-sensitive adhesive system. The inventiveness of this invention lies in the synthesis of modified amine crosslinking agents and the synergistic use of modified amine crosslinking agents with glycidyl methacrylate pressure-sensitive adhesive systems. Through the synthesis and interaction of these materials, the adhesion strength of the water-based pressure-sensitive adhesive to PET film materials can be greatly improved, achieving good light transmittance.

[0019] In this invention, after the amine structure reacts with glycidyl methacrylate, low-polarity flexible segments can be successfully synthesized into the adhesive structure, achieving extremely high light transmittance while ensuring adhesive strength. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the chemical structure of the bromoaminopyridine monomer used.

[0021] Figure 2 Digital photographs made of water-based pressure-sensitive adhesive with a light transmittance greater than 95% and an adhesive strength greater than 12N;

[0022] Figure 3 A digital photograph of the PET bonded in Example 1;

[0023] Figure 4 This is a schematic diagram of the peel strength of the bonded PET in Example 1;

[0024] Figure 5 This is a schematic diagram of the peel strength of the PET bonded in Example 2. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0026] Example 1: Water-based pressure-sensitive adhesive with a light transmittance greater than 95% and an adhesive strength greater than 12N

[0027] First, weigh 36 parts by weight of 2-bromo-6-aminopyridine, 115 parts by weight of polytetrahydrofuran with a number average molecular weight of 2000, 25 parts by weight of potassium hydroxide, and 230 parts by weight of ethyl acetate. Add 2-bromo-6-aminopyridine and polytetrahydrofuran to ethyl acetate and stir at a stirring speed of 80 rpm. After stirring, raise the system temperature to 60°C and react for 2.5 h. After the reaction is complete, remove the ethyl acetate solvent to obtain the modified amine crosslinking agent.

[0028] Next, according to the following weight proportions, weigh 210 parts of deionized water, 85 parts of isooctyl acrylate, 70 parts of n-butyl acrylate, 45 parts of methyl methacrylate, 3.5 parts of glycidyl methacrylate, 2 parts of sodium dodecylbenzenesulfonate, 8 parts of TX-10 surfactant, and 0.7 parts of ammonium persulfate. Add all the above substances to a flask and stir at 120 rpm for 20 min to obtain a pre-emulsion. Weigh 150 parts of the pre-emulsion and heat it to 81°C with a stirring rate of 80 rpm for 3 h. Then, continue to add 260 parts of the pre-emulsion dropwise to the system over 1 h. After the addition is completed, continue the reaction for 1.5 h.

[0029] Finally, according to the mass ratio, after the reaction is complete and the system temperature has cooled to room temperature, add 2.5 parts of modified amine crosslinking agent to the system. After stirring for 25 minutes, a water-based pressure-sensitive adhesive with a light transmittance greater than 95% and an adhesive strength greater than 12N can be obtained. Let the water-based pressure-sensitive adhesive stand at room temperature for 18 days. Figure 2 As shown, it still exhibits good stability. Figure 3 As shown, this emulsion exhibits good light transmittance after bonding with PET, and the total thickness of the adhesive layer and the PET layer is 60 micrometers. Figure 4 The testing process involves a 180° peel test. After cutting the sample to the width of the mold, it is placed on a universal testing machine to begin the test. Figure 4 This demonstrates the good adhesion strength of this emulsion to PET film materials.

[0030] Example 2: Water-based pressure-sensitive adhesive with a light transmittance greater than 92% and an adhesive strength greater than 10N

[0031] First, weigh 45 parts of 2-bromo-4-aminopyridine, 145 parts of polypropylene glycol with a number average molecular weight of 1000, 30 parts of sodium hydroxide, and 450 parts of ethyl acetate according to the mass ratio. Add 2-bromo-4-aminopyridine and polypropylene glycol to ethyl acetate and stir at a stirring speed of 120 rpm. After stirring, raise the system temperature to 65°C and react for 4 hours. After the reaction is completed, remove the ethyl acetate solvent to obtain the modified amine crosslinking agent.

[0032] Next, according to the following weight proportions, weigh 360 parts of deionized water, 112 parts of isooctyl acrylate, 87 parts of n-butyl acrylate, 60 parts of methyl methacrylate, 4.2 parts of glycidyl methacrylate, 2.5 parts of sodium dodecylbenzenesulfonate, 9.2 parts of TX-10 surfactant, and 0.4 parts of ammonium persulfate. Add all the above substances to a flask and stir at 88 rpm for 30 min to obtain a preemulsion. Weigh 210 parts of the preemulsion and heat it to 83°C with a stirring rate of 120 rpm for 2.5 h. Then, continue to add 310 parts of the preemulsion dropwise to the system over 1.5 h. After the addition is completed, continue the reaction for 2 h.

[0033] Finally, according to the mass ratio, after the reaction is completed and the system temperature drops to room temperature, add 3.6 parts of modified amine crosslinking agent to the system, stir for 35 minutes, and you can obtain a water-based pressure-sensitive adhesive with a light transmittance greater than 92% and an adhesive strength greater than 10N. Figure 5 The testing process involves a 180° peel test. After cutting the sample to the width of the mold, it is placed on a universal testing machine to begin the test. Figure 5 This demonstrates the good adhesion strength of this emulsion to PET film materials.

Claims

1. A method for preparing a water-based pressure-sensitive adhesive for high-transparency, high-peel strength PET bonding, characterized in that: The method is as follows: Step 1: Weigh out 10-50 parts by weight of bromoaminopyridine monomer, 70-200 parts by weight of terminal hydroxyl diol monomer, 10-35 parts by weight of strong base substance, and 200-500 parts by weight of ethyl acetate. Step 2: Add bromoaminopyridine monomer, terminal hydroxyl diol monomer and strong base to ethyl acetate, stir at 20~150 rpm for 15~30 min, after stirring, raise the system temperature to 50~70℃ and react for 2~4 h, after the reaction is completed, remove ethyl acetate to obtain modified amine crosslinking agent; Step 3: Weigh out 200-400 parts of deionized water, 70-150 parts of isooctyl acrylate, 50-100 parts of n-butyl acrylate, 30-70 parts of methyl methacrylate, 2-6 parts of glycidyl methacrylate, 2-4 parts of sodium dodecylbenzene sulfonate, 6-10 parts of TX-10 surfactant, and 0.3-0.9 parts of initiator according to the following weight proportions: Step 4: Add all the substances from Step 3 to a four-necked flask and stir at a speed of 30-150 rpm for 15-30 minutes to obtain a pre-emulsion. Step 5: Weigh 100-300 parts of the pre-emulsion and heat it to 80℃-85℃. Stir at 50-150 rpm for 2-4 hours. Then, add 200-400 parts of the pre-emulsion to the system dropwise for 1-1.5 hours. After the addition is complete, continue the reaction for 1-2 hours. Step 6: After the entire reaction is complete and the system temperature drops to room temperature, add 1-4 parts of modified amine crosslinking agent to the system, stir for 20-40 minutes, and obtain a high-permeability, high-strength peel PET adhesive water-based pressure-sensitive adhesive.

2. The preparation method of the high-penetration, high-strength peel-off PET adhesive water-based pressure-sensitive adhesive according to claim 1, characterized in that: In step one, the bromoaminopyridine monomer is one of 2-bromo-6-aminopyridine, 2-bromo-4-aminopyridine, or 4-bromo-2,6-diaminopyridine.

3. The preparation method of the high-penetration, high-strength peel-off PET adhesive water-based pressure-sensitive adhesive according to claim 1, characterized in that: In step one, the terminal hydroxyl diol monomer is one of polyethylene glycol, polypropylene glycol, or polytetrahydrofuran.

4. The preparation method of the high-penetration, high-strength peel-off PET adhesive water-based pressure-sensitive adhesive according to claim 1, characterized in that: In step one, the strong alkali substance is one of potassium hydroxide, sodium hydroxide, or calcium hydroxide.

5. The preparation method of the high-penetration, high-strength peel-off PET adhesive water-based pressure-sensitive adhesive according to claim 1, characterized in that: In step two, the initiators are ammonium persulfate and potassium persulfate.

6. A water-based pressure-sensitive adhesive for high-permeability, high-strength peeling PET bonding prepared by the preparation method according to any one of claims 1 to 5.

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