Preparation method of high-viscosity acrylic adhesive with excellent yellowing resistance

Abstract

The invention relates to a preparation method of a high-viscosity acrylic adhesive with excellent yellowing resistance, and belongs to the technical field of high polymer materials. The high-viscosity acrylic adhesive with excellent anti-yellowing performance is prepared from the following components in parts by weight: 500 to 700 parts of methyl methacrylate, 100 to 120 parts of 2-ethylhexyl acrylate, 60 to 80 parts of acrylic acid, 5 to 7 parts of 2-hydroxyethyl acrylate, 1 to 5 parts of azodiisobutyronitrile, 1500 parts of ethyl acetate, 100 to 150 parts of rosin resin, 50 parts of hydroxyl-terminated polymethylsilicone oil, 5 parts of ferric hydroxide and 4 to 6 parts of anti-yellowing agent. Phosphite ester and a benzotriazole compound in the anti-yellowing agent cooperate with each other, so that the anti-yellowing performance of the adhesive is enhanced; a maleimide group enhances intermolecular force and reduces yellowing caused by high-temperature thermal aging; the high-viscosity acrylic adhesive with excellent anti-yellowing performance prepared by the invention not only has an excellent anti-yellowing effect, but also has good persistent adhesion and high viscosity.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance. Background Art

[0002] Adhesive, also known as bonding agent or glue, is a non-metallic medium material that can tightly connect objects. It forms a thin layer between the surfaces of the adherends, but can make the bonded parts meet actual requirements in terms of mechanical properties and physical and chemical properties.

[0003] However, traditional adhesives release harmful substances when curing, threatening human health. Therefore, the use of low-volatile materials can effectively protect the health of humans and the environment from the source, but the relative adhesion of environmentally friendly adhesives is reduced. With the development of science and technology and the improvement of people's living standards, acrylic adhesives are favored because of their wide source of raw materials, simple preparation process, rapid drying and molding, high transparency, convenient use and good durability. However, acrylic adhesives are easy to react with oxygen in the air at high temperatures to form peroxides with high activity, which react with acrylic acid molecules to generate dark yellow products, causing the adhesive to turn yellow; under light conditions, ultraviolet rays can easily make the double bonds in the acrylic acid molecules undergo photo-oxidation reactions, causing the adhesive to turn yellow; therefore, the research and development of high-viscosity acrylic adhesives with excellent anti-yellowing properties has important practical significance and application value. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A high-viscosity acrylic adhesive with excellent anti-yellowing performance comprises the following raw materials in parts by weight: 500-700 parts of methyl methacrylate, 100-120 parts of isooctyl acrylate, 60-80 parts of acrylic acid, 5-7 parts of 2-hydroxyethyl acrylate, 1-5 parts of azobisisobutyronitrile, 1500 parts of ethyl acetate, 100-150 parts of rosin resin, 50 parts of hydroxyl-terminated polymethyl silicone oil, 5 parts of ferric hydroxide and 4-6 parts of an anti-yellowing agent.

[0007] The anti-yellowing agent is prepared by the following method:

[0008] Step A1: 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, dichloromethane and triethylamine were mixed, reacted at 25°C for 2h, the system was heated to 40°C, acryloyl chloride was added dropwise, reacted for 2h, cooled to room temperature, distilled, washed, filtered and dried to obtain compound 1;

[0009] Further, the usage ratio of 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, dichloromethane, triethylamine, and acryloyl chloride is 5.1-5.4 g: 20-22 mL: 2 g: 5-10 mL;

[0010] Step A2: p-Aminophenol, maleic anhydride and tetrahydrofuran were mixed, stirred in an ice-water bath for 5 min, filtered, washed, and then the temperature was adjusted to 15°C, triethylamine, toluene and diphenylphosphine chloride were added dropwise, and the temperature was slowly raised to 80°C after the addition was complete, and the mixture was kept warm for 3 h, cooled, and dried to obtain compound 2;

[0011] Further, the usage ratio of p-aminophenol, maleic anhydride, tetrahydrofuran, triethylamine, toluene, and diphenylphosphine chloride is 6.05-6.54 g: 5.1-5.3 g: 10 mL: 5.5 g: 65 g: 12-15 g;

[0012] Step A3: Disperse compound 2 and benzoyl peroxide in xylene, add compound 1 and stir evenly, heat to 90°C under nitrogen protection for 4.5h, distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain an anti-yellowing agent;

[0013] Furthermore, the usage ratio of compound 2, benzoyl peroxide, xylene and compound 1 is 3-5 g: 0.16 g: 70 mL: 5-8 g.

[0014] A method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance comprises the following steps:

[0015] S1. Mix methyl methacrylate and isooctyl acrylate evenly, stir at 65-70°C for 1 hour, then add anti-yellowing agent, acrylic acid and 2-hydroxyethyl acrylate, stir at 65-70°C for 0.5 hour, and then stir at 71-75°C for 1 hour to obtain a premix;

[0016] S2, azobisisobutyronitrile and ethyl acetate were mixed, divided into 5 equal portions, and added to the premix in sequence, each time interval being 40 minutes. After the addition was completed, the mixture was stirred at 75-78° C. for 1 hour to obtain a mixture;

[0017] S3. Evenly mix the rosin resin and hydroxyl-terminated polymethyl silicone oil, add them into the mixture, then add ferric hydroxide, and stir at 80-85°C for 1 hour to obtain a high-viscosity acrylic adhesive with excellent anti-yellowing performance.

[0018] Beneficial effects of the present invention:

[0019] The high-viscosity acrylic adhesive with excellent anti-yellowing performance of the invention has a good anti-yellowing effect and also has excellent sustained adhesion and high viscosity, thereby extending the service life of the material.

[0020] The high-viscosity acrylic adhesive with excellent anti-yellowing performance prepared by the present invention has the advantage of a macromolecular polymer and exhibits anti-yellowing performance that exceeds that of a traditional small-molecule anti-yellowing agent. The anti-yellowing agent firstly utilizes the hydroxyl group of 2-(2-hydroxy-3,5-di-tert-amylphenyl)benzotriazole to react with the acyl chloride of acryloyl chloride to synthesize compound 1; secondly, utilizes the amino group of p-aminophenol to react with maleic anhydride, and the hydroxyl group of p-aminophenol reacts with the chlorine atom of diphenylphosphine chloride to synthesize a phosphite-containing compound 2; finally, utilizes the carbon-carbon double bond copolymerization of compound 1 and compound 2 to synthesize the anti-yellowing agent. 2-(2-hydroxy-3,5-di-tert-amylphenyl)benzotriazole in the anti-yellowing agent can efficiently absorb ultraviolet light by virtue of its conjugated double bonds and aromatic rings, and by inducing thermal vibrations within the molecule and destroying the intrinsic hydrogen bonds within the molecule, the energy of ultraviolet light is converted into heat energy or light energy release, thereby reducing the damage of ultraviolet light to the yellowing of the material; at the same time, phosphite compounds can not only effectively decompose the hydroperoxides in the acrylic adhesive and prevent free radical oxidation reactions, thereby improving the stability of the adhesive, but also inhibit yellowing at high temperatures by virtue of strong redox effects, and maintain the good appearance of the adhesive. The phosphite compounds and benzotriazole compounds work synergistically to significantly enhance the anti-yellowing performance of the acrylic adhesive; in addition, the maleimide group formed by maleic anhydride and amino groups can enhance the glass transition temperature, melting point and heat resistance of the material by enhancing the intermolecular force, thereby reducing the yellowing caused by high-temperature thermal aging; in addition, the anti-yellowing agent can copolymerize with the carbon-carbon double bonds of acrylic acid to solve the migration, incompatibility and volatilization problems of traditional anti-yellowing agents. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Example 1: A method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance, comprising the following steps:

[0023] S1. Weigh the raw materials by weight: 500 parts of methyl methacrylate, 100 parts of isooctyl acrylate, 60 parts of acrylic acid, 5 parts of 2-hydroxyethyl acrylate, 1 part of azobisisobutyronitrile, 1500 parts of ethyl acetate, 100 parts of rosin resin, 50 parts of hydroxyl-terminated polymethyl silicone oil, 5 parts of ferric hydroxide, and 4 parts of anti-yellowing agent (prepared in this embodiment); mix methyl methacrylate and isooctyl acrylate evenly, stir at 65° C. for 1 h, then add anti-yellowing agent, acrylic acid and 2-hydroxyethyl acrylate, stir at 65° C. for 0.5 h, and then stir at 71° C. for 1 h to obtain a premix;

[0024] S2, azobisisobutyronitrile and ethyl acetate were mixed, divided into 5 equal parts, and added to the premix in sequence, each time interval was 40 minutes. After the addition was completed, the mixture was stirred at 75° C. for 1 hour to obtain a mixture;

[0025] S3, after mixing rosin resin and hydroxyl-terminated polymethyl silicone oil evenly, add them to the mixture, then add ferric hydroxide, and stir at 80°C for 1 hour to obtain a high-viscosity acrylic adhesive with excellent anti-yellowing performance;

[0026] The anti-yellowing agent is prepared by the following method:

[0027] Step A1: 5.1 g of 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, 20 mL of dichloromethane and 2 g of triethylamine were mixed, reacted at 25° C. for 2 h, the system was heated to 40° C., 5 mL of acryloyl chloride was added dropwise, reacted for 2 h, cooled to room temperature, distilled, washed, filtered and dried to obtain compound 1;

[0028] Step A2: 6.05 g of p-aminophenol, 5.1 g of maleic anhydride and 10 mL of tetrahydrofuran were mixed, stirred in an ice-water bath for 5 min, filtered, washed, and then the temperature was adjusted to 15°C, 5.5 g of triethylamine, 65 g of toluene and 12 g of diphenylphosphine chloride were added dropwise, and after the addition was complete, the temperature was slowly raised to 80°C, and the reaction was kept at this temperature for 3 h, cooled, and dried to obtain compound 2;

[0029] Step A3: Disperse 3 g of compound 2 and 0.16 g of benzoyl peroxide in 70 mL of xylene, add 5 g of compound 1 and stir evenly. Under nitrogen protection, heat to 90 ° C to react for 4.5 hours, distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain an anti-yellowing agent.

[0030] Embodiment 2: A method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance, comprising the following steps:

[0031] S1. Weigh the raw materials by weight: 600 parts of methyl methacrylate, 110 parts of isooctyl acrylate, 70 parts of acrylic acid, 6 parts of 2-hydroxyethyl acrylate, 3 parts of azobisisobutyronitrile, 1500 parts of ethyl acetate, 125 parts of rosin resin, 50 parts of hydroxyl-terminated polymethyl silicone oil, 5 parts of ferric hydroxide, and 5 parts of anti-yellowing agent (prepared in this embodiment); mix methyl methacrylate and isooctyl acrylate evenly, stir at 67° C. for 1 h, then add anti-yellowing agent, acrylic acid and 2-hydroxyethyl acrylate, stir at 67° C. for 0.5 h, and then stir at 73° C. for 1 h to obtain a premix;

[0032] S2, azobisisobutyronitrile and ethyl acetate were mixed, divided into 5 equal portions, and added to the premix in sequence, each time interval being 40 minutes. After the addition was completed, the mixture was stirred at 76° C. for 1 hour to obtain a mixture;

[0033] S3, after mixing rosin resin and hydroxyl-terminated polymethyl silicone oil evenly, add them to the mixture, then add ferric hydroxide, and stir at 83°C for 1 hour to obtain a high-viscosity acrylic adhesive with excellent anti-yellowing performance;

[0034] The anti-yellowing agent is prepared by the following method:

[0035] Step A1: 5.25 g of 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, 21 mL of dichloromethane and 2 g of triethylamine were mixed, reacted at 25° C. for 2 h, the system was heated to 40° C., 7 mL of acryloyl chloride was added dropwise, reacted for 2 h, cooled to room temperature, distilled, washed, filtered and dried to obtain compound 1;

[0036] Step A2: 6.3 g of p-aminophenol, 5.2 g of maleic anhydride and 10 mL of tetrahydrofuran were mixed, stirred in an ice-water bath for 5 min, filtered, washed, and then the temperature was adjusted to 15°C, 5.5 g of triethylamine, 65 g of toluene and 13.5 g of diphenylphosphine chloride were added dropwise, and after the addition was complete, the temperature was slowly raised to 80°C, and the reaction was kept at this temperature for 3 h, cooled, and dried to obtain compound 2;

[0037] Step A3: Disperse 4 g of compound 2 and 0.16 g of benzoyl peroxide in 70 mL of xylene, add 7.5 g of compound 1 and stir evenly. Under nitrogen protection, heat to 90 ° C and react for 4.5 hours. Distill under reduced pressure, cool, wash, filter and vacuum dry to obtain an anti-yellowing agent.

[0038] Embodiment 3: A method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance, comprising the following steps:

[0039] S1. Weigh the raw materials by weight: 700 parts of methyl methacrylate, 120 parts of isooctyl acrylate, 80 parts of acrylic acid, 7 parts of 2-hydroxyethyl acrylate, 5 parts of azobisisobutyronitrile, 1500 parts of ethyl acetate, 150 parts of rosin resin, 50 parts of hydroxyl-terminated polymethyl silicone oil, 5 parts of ferric hydroxide, and 6 parts of anti-yellowing agent (prepared in this embodiment); mix methyl methacrylate and isooctyl acrylate evenly, stir at 70° C. for 1 hour, then add anti-yellowing agent, acrylic acid and 2-hydroxyethyl acrylate, stir at 70° C. for 0.5 hour, and then stir at 75° C. for 1 hour to obtain a premix;

[0040] S2, azobisisobutyronitrile and ethyl acetate were mixed, divided into 5 equal parts, and added to the premix in sequence, each time interval was 40 minutes. After the addition was completed, the mixture was stirred at 78° C. for 1 hour to obtain a mixture;

[0041] S3, after mixing rosin resin and hydroxyl-terminated polymethyl silicone oil evenly, add them to the mixture, then add ferric hydroxide, and stir at 85°C for 1 hour to obtain a high-viscosity acrylic adhesive with excellent anti-yellowing performance;

[0042] The anti-yellowing agent is prepared by the following method:

[0043] Step A1: 5.4 g of 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, 22 mL of dichloromethane and 2 g of triethylamine were mixed, reacted at 25° C. for 2 h, the system was heated to 40° C., 10 mL of acryloyl chloride was added dropwise, reacted for 2 h, cooled to room temperature, distilled, washed, filtered and dried to obtain compound 1;

[0044] Step A2: 6.54 g of p-aminophenol, 5.3 g of maleic anhydride and 10 mL of tetrahydrofuran were mixed, stirred in an ice-water bath for 5 min, filtered, washed, and then the temperature was adjusted to 15°C, 5.5 g of triethylamine, 65 g of toluene and 15 g of diphenylphosphine chloride were added dropwise, and after the addition was complete, the temperature was slowly raised to 80°C, and the reaction was kept at this temperature for 3 h, cooled, and dried to obtain compound 2;

[0045] Step A3: Disperse 5 g of compound 2 and 0.16 g of benzoyl peroxide in 70 mL of xylene, add 8 g of compound 1 and stir evenly. Under nitrogen protection, heat to 90 ° C to react for 4.5 hours, distill under reduced pressure, cool, wash, filter, and vacuum dry to obtain an anti-yellowing agent.

[0046] Comparative Example: This comparative example is a high-viscosity acrylic adhesive with excellent anti-yellowing performance. The difference from Example 3 is that an equal amount of 1,6-hexamethylene-bis(N,N-dimethylaminourea) is used to replace the anti-yellowing agent prepared in Example 3, and the rest are the same.

[0047] Performance test: The high-viscosity acrylic adhesive with excellent anti-yellowing performance obtained in Examples 1-3 and Comparative Examples 1-2 was applied to the surface of the substrate, with standard test size, and the peeling force was tested according to the standard GBT 2792-2014, and the holding force was tested according to the standard GB4851-1998; the sample was placed in a UV aging box, the conditions were 60°C, 0.86w / cm 2 , place for 500 hours, and test the yellow index; the test results are shown in the following table:

[0048] Example 1 Example 2 Example 3 Comparative Example Peel force (gf / 25mm) 4.3 3.9 4.1 2.6 Holding force(h) 130 128 127 95 Yellow Index 0.28 0.29 0.30 0.43

[0049] It can be seen from the test data in the table that the high-viscosity acrylic adhesive with excellent anti-yellowing performance prepared in Example 1 has excellent anti-yellowing effect. It can also be seen from the above table that the high-viscosity acrylic adhesive with excellent anti-yellowing performance prepared in the present invention has good sustained adhesion and high viscosity.

[0050] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance, characterized in that: The specific steps include: S1. Weigh the raw materials by weight: 500-700 parts of methyl methacrylate, 100-120 parts of isooctyl acrylate, 60-80 parts of acrylic acid, 5-7 parts of 2-hydroxyethyl acrylate, 1-5 parts of azobisisobutyronitrile, 1500 parts of ethyl acetate, 100-150 parts of rosin resin, 50 parts of hydroxyl-terminated polymethyl silicone oil, 5 parts of ferric hydroxide, and 4-6 parts of anti-yellowing agent; mix methyl methacrylate and isooctyl acrylate evenly, stir at 65-70° C. for 1 hour, then add the anti-yellowing agent, acrylic acid and 2-hydroxyethyl acrylate, stir at 65-70° C. for 0.5 hour, and then stir at 71-75° C. for 1 hour to obtain a premix; S2, azobisisobutyronitrile and ethyl acetate were mixed, divided into 5 equal portions, and added to the premix in sequence, each time interval being 40 minutes. After the addition was completed, the mixture was stirred at 75-78° C. for 1 hour to obtain a mixture; S3. Evenly mix the rosin resin and hydroxyl-terminated polymethyl silicone oil, add them into the mixture, then add ferric hydroxide, and stir at 80-85°C for 1 hour to obtain a high-viscosity acrylic adhesive with excellent anti-yellowing performance.

2. The method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance according to claim 1 is characterized in that: The anti-yellowing agent is prepared by the following method: Step A1: 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, dichloromethane and triethylamine were mixed, reacted at 25°C for 2h, the system was heated to 40°C, acryloyl chloride was added dropwise, reacted for 2h, cooled to room temperature, distilled, washed, filtered and dried to obtain compound 1; Step A2: p-Aminophenol, maleic anhydride and tetrahydrofuran were mixed, stirred in an ice-water bath for 5 min, filtered, washed, and then the temperature was adjusted to 15°C, triethylamine, toluene and diphenylphosphine chloride were added dropwise, and the temperature was slowly raised to 80°C after the addition was complete, and the mixture was kept warm for 3 h, cooled, and dried to obtain compound 2; Step A3: Disperse compound 2 and benzoyl peroxide evenly in xylene, then add compound 1 and stir evenly, heat to 90°C under nitrogen protection and react for 4.5 hours, distill under reduced pressure, cool, wash, filter and vacuum dry to obtain an anti-yellowing agent.

3. The method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance according to claim 2, characterized in that: In step A1, the usage ratio of 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, dichloromethane, triethylamine and acryloyl chloride is 5.1-5.4 g: 20-22 mL: 2 g: 5-10 mL.

4. The method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance according to claim 2, characterized in that: In step A2, the usage ratio of p-aminophenol, maleic anhydride, tetrahydrofuran, triethylamine, toluene and diphenylphosphine chloride is 6.05-6.54 g: 5.1-5.3 g: 10 mL: 5.5 g: 65 g: 12-15 g.

5. The method for preparing a high-viscosity acrylic adhesive with excellent anti-yellowing performance according to claim 2, characterized in that: In step A3, the usage ratio of compound 2, benzoyl peroxide, xylene and compound 1 is 3-5 g: 0.16 g: 70 mL: 5-8 g.