Benzene-free water-based acrylic adhesive as well as preparation method and application thereof

Abstract

The invention discloses a benzene-free water-based acrylic adhesive as well as a preparation method and application thereof. The benzene-free water-based acrylic adhesive is prepared from the following raw materials in parts by weight: 45 to 55 parts of butyl acrylate, 25 to 35 parts of methyl methacrylate, 5 to 15 parts of hydroxyethyl acrylate, 1 to 5 parts of an emulsifier, 1 to 3 parts of ammonium persulfate, 90 to 120 parts of deionized water, 1 to 3 parts of a thickening agent, 1 to 3 parts of a defoaming agent and 1 to 3 parts of a flatting agent. The benzene-free water-based acrylic adhesive disclosed by the invention is benzene-free and environment-friendly, does not contain harmful substances such as benzene, and meets the environment-friendly requirement. The corrosion of the electrolyte of the lithium battery can be effectively resisted, and the integrity and the stability of the protective film are kept. The bonding strength is high, the good bonding performance on materials such as lithium battery electrodes is achieved, and it is ensured that the protective film is firmly attached. And the lithium battery has good flexibility, adapts to deformation and vibration of the lithium battery in the use process, and is not easy to crack and fall off.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly relates to a benzene-free waterborne acrylic adhesive, its preparation method and application. Background Art

[0002] With the wide application of lithium batteries, the requirements for their safety and stability are getting higher and higher. As an important part of lithium batteries, the protective film plays a role in protecting the electrodes and preventing electrolyte leakage. In the electrolyte-resistant protective film of lithium batteries, waterborne acrylic adhesives can maintain insolubility in organic electrolytes through their rich polar functional groups, showing high chemical stability and mechanical stability. This property enables waterborne acrylic adhesives to exhibit excellent electrochemical performance in different structural parts of lithium batteries. However, traditional adhesives may contain harmful substances such as benzene, which not only cause harm to the environment and human health, but also may affect the performance and lifespan of lithium batteries.

[0003] Therefore, it is of great practical significance to develop a benzene-free waterborne acrylic adhesive for use in the electrolyte-resistant protective film of lithium batteries. Summary of the Invention

[0004] To solve the deficiencies of the prior art, the purpose of the present invention is to provide a benzene-free waterborne acrylic adhesive, its preparation method and application. The benzene-free waterborne acrylic adhesive of the present invention is benzene-free and environmentally friendly: it does not contain harmful substances such as benzene and meets environmental protection requirements. It has good electrolyte resistance: it can effectively resist the erosion of lithium battery electrolytes and maintain the integrity and stability of the protective film. It has high bonding strength: it has good bonding performance to materials such as lithium battery electrodes, ensuring that the protective film is firmly attached. It has good flexibility: it can adapt to the deformation and vibration of lithium batteries during use and is not prone to cracking and falling off.

[0005] The technical problems to be solved by the present invention are achieved through the following technical solutions: In the first aspect, a benzene-free waterborne acrylic adhesive is composed of the following raw materials in parts by weight: 45-55 parts of butyl acrylate, 25-35 parts of methyl methacrylate, 5-15 parts of hydroxyethyl acrylate, 1-5 parts of emulsifier, 1-3 parts of ammonium persulfate, 90-120 parts of deionized water, 1-3 parts of thickener, 1-3 parts of defoamer, and 1-3 parts of leveling agent.

[0006] Butyl acrylate, methyl methacrylate and hydroxyethyl acrylate undergo a polymerization reaction to form a high molecular polymer, providing the basic bonding performance of the adhesive. The initiator is used to initiate the polymerization reaction and control the reaction rate and the molecular weight of the polymer. The emulsifier makes the acrylate monomers form a stable emulsion system in water. The functional additives include thickeners, defoamers, leveling agents, etc., which are used to adjust the performance of the adhesive.

[0007] Second aspect, a preparation method of a benzene-free waterborne acrylic adhesive, which comprises the following steps: adding butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, an emulsifier and a part of deionized water into a reaction kettle, stirring evenly to form a pre-emulsion; dissolving ammonium persulfate in another part of deionized water to obtain an initiator solution; under heating conditions, slowly dropping the initiator solution into the pre-emulsion, and after the reaction is completed, adding a thickener, an antifoaming agent and a leveling agent, and stirring evenly to obtain the benzene-free waterborne acrylic adhesive.

[0008] As a further improvement of the present invention, the emulsifier is OP-10.

[0009] As a further improvement of the present invention, the thickener is hydroxyethyl cellulose.

[0010] As a further improvement of the present invention, the antifoaming agent is an organosilicon antifoaming agent.

[0011] As a further improvement of the present invention, the leveling agent is a polyacrylate leveling agent.

[0012] Third aspect, an application of a benzene-free waterborne acrylic adhesive in the preparation of an electrolyte-resistant protective film for a lithium battery.

[0013] Coat the benzene-free waterborne acrylic adhesive on a protective film substrate, and through processes such as drying and curing, form an electrolyte-resistant protective film for a lithium battery. The protective film can be cut and adhered according to needs, and is applied to different types of lithium batteries.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. Environmental protection: The benzene-free waterborne acrylic adhesive does not contain harmful substances, does not volatilize solvents, will not cause oxidation to the protected surface of the lithium battery, and is friendly to the environment and human health.

[0015] 2. Superior performance: 1) Good electrolyte resistance: Flatly attach the aluminum foil to immerse in the electrolyte at 85°C for 4 hours, without color fading, displacement or shedding; 2) High bonding strength: Test the peel strength on a steel plate from -35°C to +150°C and maintain it at 9-15 N / 2.5 cm and there is no residual glue after peeling; 3) Good flexibility: Attach to the 90° corner of the aluminum shell, 2 mm double 85 test for 1000 h without edge warping, and can meet the requirements of the lithium battery for the protective film.

[0016] 3. Simple preparation process and high safety: Adopt a conventional emulsion polymerization method, with a mature process and easy to operate. Water-based system: Use water as the dispersion medium, which is safe, non-toxic, non-flammable and explosive.

[0017] 4. Low cost: The raw materials are widely sourced and the prices are relatively low, reducing the production cost.

[0018] 5. This benzene-free aqueous acrylic adhesive is applied to the electrolyte-resistant protective film of lithium batteries and has broad market prospects. With the rapid development of the lithium battery industry, the demand for environmentally friendly and high-performance protective films is increasing continuously. This technology will provide strong guarantee for the safe and stable operation of lithium batteries. Detailed implementation manners

[0019] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0020] Example 1 A benzene-free aqueous acrylic adhesive is composed of the following raw materials in parts by weight: 50 parts of butyl acrylate, 30 parts of methyl methacrylate, 10 parts of hydroxyethyl acrylate, 3 parts of emulsifier OP-10, 1 part of ammonium persulfate, 100 parts of deionized water, 2 parts of thickener hydroxyethyl cellulose, 1 part of defoamer silicone defoamer, and 1 part of leveling agent polyacrylate leveling agent.

[0021] Preparation method: Add butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, emulsifier OP-10 and 50 parts of deionized water into a reaction kettle, stir evenly to form a pre-emulsion; dissolve ammonium persulfate in 50 parts of deionized water to obtain an initiator solution. At 80 °C, slowly drop the initiator solution into the pre-emulsion. If separated, excessive initiator will cause explosive polymerization, and excessive monomer will also cause explosive polymerization. React for 4 hours. After the reaction is completed, add a thickener, a defoamer and a leveling agent, and stir evenly to obtain a benzene-free aqueous acrylic adhesive.

[0022] Application: Coat this adhesive on the PET protective film substrate, and dry it at 125 °C for 5 minutes to cure and form an electrolyte-resistant protective film for lithium batteries.

[0023] Perform performance tests on the protective film. The results show that: 1) Good electrolyte resistance: Flatly stick the aluminum foil into the electrolyte at 85 °C for 4 hours, without color fading, displacement or shedding; 2) High bonding strength: Test the peel strength on the steel plate from -35 °C to +150 °C and keep it at 9-15 N / 2.5 cm without residual glue after peeling; 3) Good flexibility: Stick the aluminum shell at a 90° corner, perform double 85 tests at 2 mm for 1000 h without edge warping, which can meet the requirements of lithium batteries for the protective film. That is, this protective film has good electrolyte resistance, bonding strength and flexibility.

[0024] Example 2 A benzene-free water-based acrylic adhesive is composed of the following raw materials in parts by weight: 45 parts of butyl acrylate, 35 parts of methyl methacrylate, 5 parts of hydroxyethyl acrylate, 1 part of emulsifier OP-10, 3 parts of ammonium persulfate, 120 parts of deionized water, 1 part of thickener hydroxyethyl cellulose, 3 parts of defoaming agent silicone defoaming agent, and 2 parts of leveling agent polyacrylate leveling agent.

[0025] Preparation method: Add butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, emulsifier OP-10 and 60 parts of deionized water into a reactor, stir evenly to form a pre-emulsion; dissolve ammonium persulfate in 60 parts of deionized water to obtain an initiator solution. At 80°C, slowly drop the initiator solution into the pre-emulsion. If separated, excessive initiator will cause implosion, and excessive monomer will also cause implosion. The reaction lasts for 4 hours. After the reaction is completed, add thickener, defoamer and leveling agent, stir evenly, and obtain a benzene-free water-based acrylic adhesive.

[0026] Application: The adhesive is coated on the PET protective film substrate, dried at 125°C for 5 minutes, and cured to form a lithium battery electrolyte-resistant protective film.

[0027] The protective film was tested for performance, and the results showed that: 1) Good electrolyte resistance: The flat aluminum foil was immersed in electrolyte at 85℃ / 4h without fading, shifting, or falling off; 2) High bonding strength: The peeling force of the steel plate test at -35℃ to +150℃ remained at 9-15N / 2.5cm and no residual glue was left after peeling; 3) Good flexibility: The aluminum shell was tested at 90° corners and 2mm double 85 for 1000h without warping, which can meet the requirements of lithium batteries for protective films. That is, the protective film has good electrolyte resistance, bonding strength and flexibility.

[0028] Example 3 A benzene-free water-based acrylic adhesive is composed of the following raw materials in parts by weight: 55 parts of butyl acrylate, 35 parts of methyl methacrylate, 15 parts of hydroxyethyl acrylate, 5 parts of emulsifier OP-10, 2 parts of ammonium persulfate, 90 parts of deionized water, 3 parts of thickener hydroxyethyl cellulose, 2 parts of defoamer silicone defoamer, and 3 parts of leveling agent polyacrylate leveling agent.

[0029] Preparation method: Add butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, emulsifier OP-10 and 50 parts of deionized water into a reactor, stir evenly to form a pre-emulsion; dissolve ammonium persulfate in 40 parts of deionized water to obtain an initiator solution. At 80°C, slowly drop the initiator solution into the pre-emulsion. If separated, excessive initiator will cause implosion, and excessive monomer will also cause implosion. The reaction lasts for 4 hours. After the reaction is completed, add thickener, defoamer and leveling agent, stir evenly, and obtain a benzene-free water-based acrylic adhesive.

[0030] Application: Coat this adhesive on the PET protective film substrate, dry it at 125°C for 5 minutes, and cure to form a lithium battery electrolyte-resistant protective film.

[0031] Perform performance tests on the protective film. The results show that: 1) Good electrolyte resistance: Flatly stick the aluminum foil into the electrolyte at 85°C for 4 hours, without color fading, displacement, or peeling; 2) High bonding strength: Test the peel strength on a steel plate from -35°C to +150°C, and it remains at 9 - 15 N / 2.5 cm without residual glue after peeling; 3) Good flexibility: Stick to the aluminum shell at a 90° corner, 2 mm double 85 test for 1000 hours without edge lifting, which can meet the requirements of lithium batteries for the protective film. That is, this protective film has good electrolyte resistance, bonding strength, and flexibility.

[0032] The above-described embodiments only represent the implementation modes of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention's patent. Any technical solutions obtained by means of equivalent replacement or equivalent transformation should fall within the protection scope of the present invention.

Claims

1. A benzene-free water-based acrylic adhesive, characterized in that: The invention is composed of the following raw materials in parts by weight: 45-55 parts of butyl acrylate, 25-35 parts of methyl methacrylate, 5-15 parts of hydroxyethyl acrylate, 1-5 parts of emulsifier, 1-3 parts of ammonium persulfate, 90-120 parts of deionized water, 1-3 parts of thickener, 1-3 parts of defoamer and 1-3 parts of leveling agent.

2. The benzene-free water-based acrylic adhesive according to claim 1, characterized in that: The emulsifier is OP-10.

3. The benzene-free water-based acrylic adhesive according to claim 1, characterized in that: The thickener is hydroxyethyl cellulose.

4. The benzene-free water-based acrylic adhesive according to claim 1, characterized in that: The defoamer is an organosilicon defoamer.

5. The benzene-free water-based acrylic adhesive according to claim 1, characterized in that: The leveling agent is a polyacrylate leveling agent.

6. A method for preparing the benzene-free water-based acrylic adhesive as claimed in claim 1, characterized in that: It includes the following steps: Butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, an emulsifier and a portion of deionized water are added into a reactor and stirred evenly to form a pre-emulsion; ammonium persulfate is dissolved in another portion of deionized water to obtain an initiator solution; under heating conditions, the initiator solution is slowly added dropwise to the pre-emulsion; after the reaction is completed, a thickener, a defoamer and a leveling agent are added and stirred evenly to obtain a benzene-free water-based acrylic adhesive.

7. The method for preparing the benzene-free water-based acrylic adhesive according to claim 6, characterized in that: The emulsifier is OP-10.

8. The method for preparing the benzene-free water-based acrylic adhesive according to claim 7, characterized in that: The thickener is hydroxyethyl cellulose.

9. The method for preparing the benzene-free water-based acrylic adhesive according to claim 8, characterized in that: The defoaming agent is an organosilicon defoaming agent; the leveling agent is a polyacrylate leveling agent.

10. Use of a benzene-free water-based acrylic adhesive in the preparation of a lithium battery electrolyte-resistant protective film, characterized in that: The benzene-free water-based acrylic adhesive is the benzene-free water-based acrylic adhesive as claimed in claim 1.