Acrylic resin with high impact resistance and method for preparing the same

Abstract

The application discloses a kind of high impact resistance acrylic resin and preparation method thereof, it is made of acrylic acid, caprolactone, p-toluene sulfonic acid, p-hydroxyanisole (MEHQ), styrene, butyl acrylate, initiator, ethylene glycol butyl ether and other raw materials.The application obtains a water-soluble acrylic resin by optimizing the synthesis path.And the application obtains the best raw material composition and proportion by a large number of experiments screening, and preferably obtains a component ratio scientific and reasonable, and synthesizes a water-soluble acrylic resin with good impact resistance, high hardness and good adhesion.

Description

Technical Field

[0001] This invention relates to an aqueous acrylic resin, belonging to the field of polymer resin technology. Background Technology

[0002] Water-soluble acrylic resins refer to resins with certain polar functional groups (carboxyl or hydroxyl groups) in their structure, which achieve water solubility upon the addition of amines. Conventional water-soluble acrylic resins use acrylic acid or methacrylic acid to provide carboxyl groups. To improve the impact resistance of the paint film, the glass transition temperature of the resin must be lowered, which limits the hardness of the paint film to H when impacted by 50 kg.

[0003] This invention, through the design of a reasonable pathway and extensive experimental screening, and by selecting caprolactone, acrylic monomer, initiator, and synthesis conditions, has developed a water-soluble acrylic resin with good water solubility, high hardness, good impact performance, and good adhesion. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to address the shortcomings of existing technologies by introducing long-chain carboxyl groups into waterborne acrylic resins and optimizing the composition of acrylic resin monomers to obtain a water-soluble acrylic resin with good water solubility, good impact resistance, and high hardness, thereby overcoming the deficiencies of existing technologies.

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

[0006] An acrylic resin with high impact resistance is characterized in that it is made from the following raw materials: acrylic acid, caprolactone, p-toluenesulfonic acid, p-hydroxyanisole (MEHQ), styrene, butyl acrylate, initiator, and ethylene glycol butyl ether.

[0007] A method for preparing an acrylic resin with high impact resistance includes the following steps:

[0008] (1) Preparation of prepolymer:

[0009] Acrylic acid, caprolactone, p-toluenesulfonic acid, and p-hydroxyanisole MEHQ were weighed separately, added to the reaction apparatus, and heated to react. The reaction ended when the acid value reached the required level, and the prepolymer was obtained.

[0010] (2) According to the weight percentage, styrene, acrylic acid, butyl acrylate, part of the initiator and the prepolymer prepared in step (1) are mixed and added to the dropping tank;

[0011] A certain amount of ethylene glycol butyl ether is added to the reaction apparatus. After heating to 140-145℃, the mixture in the dropping vessel is added dropwise over 4-4.5 hours. After the addition is complete, the mixture is kept at the temperature for 0.5-1 hour. Then, the remaining initiator is added, and the mixture is kept at the temperature for another 0.5-1 hour to obtain the final product.

[0012] As a preferred embodiment, the method for preparing the above-mentioned high-impact-resistant acrylic resin includes the following steps:

[0013] (1) Preparation of prepolymer:

[0014] Add 380g of acrylic acid, 620g of caprolactone, 1.5g of p-toluenesulfonic acid, and 1g of p-hydroxyanisole MEHQ to the reaction apparatus by weight, heat to 95-100℃, and react for 5-6 hours. The reaction ends when the acid value is below 10mgKOH / g, and the prepolymer is obtained.

[0015] (2) By weight percentage, 40% styrene, 8% butyl acrylate, 0.5% initiator and 11% prepolymer prepared in step (1) are mixed and added to the dropping tank.

[0016] In the reaction apparatus, add 40% ethylene glycol butyl ether by weight percentage. After heating to 140-145℃, add the mixture from the dropper dropwise over 4-4.5 hours. After the dropwise addition is complete, keep the temperature for 0.5-1 hour. Then add the remaining 0.5% initiator and keep the temperature for another 0.5-1 hour to obtain the final product.

[0017] As a preferred embodiment, in the above-described method for preparing high-impact acrylic resin, the initiator is tert-butyl peroxide.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0019] The impact performance of a paint film is closely related to two factors: 1. The resin's intrinsic TG (thermoplastic charge); higher TG results in poorer impact performance. 2. The length of the crosslinking linkages. Currently, waterborne acrylic resins are commonly used, introducing carboxyl groups through acrylic acid or methacrylic acid. The crosslinking point between the carboxyl and methoxy groups is one carbon-oxygen bond length. However, this invention uses a prepolymer obtained by reacting acrylic acid and caprolactone to produce carboxyl groups. The crosslinking point between the carboxyl and methoxy groups is six carbon-carbon bonds long. This six-fold increase in crosslinking length results in a paint film with significantly better impact performance, enabling the resin to withstand an impact of 50 kg and achieve a hardness of 3H, demonstrating excellent technical results. Detailed Implementation

[0020] Example 1

[0021] 1. A method for preparing a water-based acrylic resin, comprising the following steps:

[0022] (1) Add 380 g of acrylic acid, 660 g of caprolactone, 1.5 g of p-toluenesulfonic acid, and 1 g of MEHQ to the reaction apparatus. Heat to 95℃-100℃ and maintain at 95℃-100℃ for 5-6 hours. After 5 hours, start measuring the acid value (acid-base titration method). Add the acid value every half hour. When the acid value is below 10 mg KOH / g, the prepolymer is obtained. Cool it down and package it for later use.

[0023] (2) Mix 40g of styrene, 11g of prepolymer, 8g of butyl propylene glycol, and 0.5g of tert-butyl peroxide evenly and add them to the dropping container;

[0024] (3) Add 40 g of ethylene glycol butyl ether to the reactor. When the temperature reaches 140-145℃, add the mixed monomers from step (2) and 0.5 g of tert-butyl peroxide initiator. The addition is completed in 4 hours. After the addition is completed, keep warm for 1-2 hours to obtain the product.

[0025] 2. The waterborne acrylic resin prepared in Example 1 and various fillers in Table 1 below were added to the preparation tank in proportion, stirred and filtered, and sprayed onto a standard steel plate with a film thickness of 25 μm. After surface drying for 10 minutes, the film was baked in an oven at 150℃ for 25-30 minutes and placed in a constant temperature room for 30 minutes before testing the performance as shown in Table 2.

[0026] Table 1. Formulation composition of acrylic resin industrial coatings

[0027]

[0028] Table 2 Results of Coating Film Performance Tests

[0029] Appearance Smooth and free of particles Visual inspection luster More than 90 GB / T 9754-2007 Hardness (pencil scratch) 3H GB / T 6739-2006 Impact (recoil) (kg.cm) 50 GB / T1732-93 Adhesion (circle test) Level 1 GB / T1720-79 .

[0030] Example 2

[0031] 1. A method for preparing a water-based acrylic resin, comprising the following steps:

[0032] (1) Add 380 g of acrylic acid, 660 g of caprolactone, 1.5 g of p-toluenesulfonic acid, and 1 g of MEHQ to the reaction apparatus. Heat to 95℃-100℃ and maintain at 95℃-100℃ for 5-6 hours. After 5 hours, start measuring the acid value (acid-base titration method). Add the acid value every half hour. When the acid value is lower than 10 mg KOH / g, cool down to obtain the prepolymer, which is then packaged for later use.

[0033] (2) Mix 36g of styrene, 15g of prepolymer, 8g of butyl propylene glycol, and 0.5g of tert-butyl peroxide evenly and add them to the dropping container;

[0034] (3) Add 40 g of ethylene glycol butyl ether to the reactor. When the temperature reaches 140-145℃, add the mixed monomers from step (2) and 0.5 g of tert-butyl peroxide initiator. The addition is completed in 4 hours. After the addition is completed, keep the temperature for 1-2 hours.

[0035] The acrylic resin prepared in Example 2 and various fillers in Table 3 below were added to the preparation tank in proportion, stirred evenly, filtered, and sprayed onto a standard steel plate with a film thickness of 25 μm. After surface drying for 10 minutes, the film was baked in an oven at 150°C for 25-30 minutes and the performance was tested, as shown in Table 4.

[0036] Table 3. Formulation composition of acrylic resin industrial coatings

[0037] Raw material name Weight (g) Example 2 Waterborne acrylic resin 50 Leveling agent (G390 polyester leveling agent) 0.2 Defoamer (Q010 polymeric defoamer) 0.2 Dimethylethanolamine 2.6 Propylene glycol methyl ether (PM) 10 Amino resin 5717 15 Ethylene glycol ethyl ether (BCS) 10 water 12 total 100 .

[0038] Table 4 Results of Coating Film Performance Tests

[0039]

[0040]

[0041] Example 3

[0042] (1) Add 36g of styrene, 15g of acrylic acid, 8g of butyl propylene, and 0.5g of tert-butyl peroxide to the mixing tank, stir well, and then add to the dropping tank.

[0043] (2) Add 40g of ethylene glycol butyl ether to the reaction vessel. When the temperature reaches 140-145℃, add 0.5g of the mixed monomer and the initiator tert-butyl peroxide in the dropping tank of step (1) and drop for 4 hours. Keep warm for 1-2 hours to obtain acrylic resin.

[0044] The acrylic resin prepared in Example 3 and various fillers in Table 5 below were added to the preparation tank in proportion, stirred evenly, filtered, and sprayed onto a standard steel plate with a film thickness of 25 μm. After surface drying for 10 minutes, the film was baked in an oven at 150°C for 25-30 minutes and the performance was tested, as shown in Table 6.

[0045] Table 5. Formulation Composition of Acrylic Resin Industrial Coatings

[0046] Raw material name Weight (g) Example 3 Waterborne acrylic resin 50 Leveling agent (G390 polyester leveling agent) 0.2 Defoamer (Q010 polymeric defoamer) 0.2 Dimethylethanolamine 2.6 Propylene glycol methyl ether (PM) 10 Amino resin 5717 15 Ethylene glycol ethyl ether (BCS) 10 wetting agent 0.2 water 12 total 100 .

[0047] Table 6. Results of paint film performance tests:

[0048]

[0049]

[0050] The comparative results of Examples 1 and 3 show that increasing the amount of the prepolymer synthesized in this invention significantly improves the impact performance of the paint film. A comparison of Examples 1 and 2 demonstrates that when the prepolymer content is 11% of the formulation amount, not only does the resin achieve an impact strength of 50 kg, but the hardness also reaches 3H, achieving excellent technical results. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an acrylic resin with impact-resistant properties, characterized in that, Includes the following steps: (1) Preparation of prepolymer: Add 380g of acrylic acid, 620g of caprolactone, 1.5g of p-toluenesulfonic acid, and 1g of p-hydroxyanisole MEHQ to the reaction apparatus by weight, heat to 95-100℃, and react for 5-6 hours. The reaction ends when the acid value is below 10 mgKOH / g, and the prepolymer is obtained. (2) By weight percentage, 40% styrene, 8% butyl acrylate, 0.5% initiator and 11% prepolymer prepared in step (1) are mixed and added to the dropping tank; In the reaction apparatus, add 40% ethylene glycol butyl ether by weight percentage. After heating to 140-145℃, add the mixture from the dropper dropwise over 4-4.5 hours. After the dropwise addition is complete, keep the temperature for 0.5-1 hour. Then add the remaining 0.5% initiator and keep the temperature for another 0.5-1 hour to obtain the final product.

2. The method for preparing the impact-resistant acrylic resin according to claim 1, characterized in that, The initiator is tert-butyl peroxide.

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