Low-temperature-cured high-performance water-soluble aluminum powder baking paint acrylic resin and preparation method thereof

Abstract

The application discloses a low-temperature curing high-performance water-soluble aluminum powder baking paint acrylic resin and a preparation method thereof, which is prepared from raw materials of styrene, acrylic acid, methacrylic acid, butyl acrylate, hydroxyethyl acrylate, TBPIN, ethylene glycol tert-butyl ether, ethanol and isooctyl acrylate. The application adopts a free radical polymerization process, and through a large number of experiments, methacrylic acid and acrylic acid are simultaneously used, the proportion of the two is controlled, and the best acrylic monomer and reaction conditions are selected and adjusted, so that the acrylic resin for water-soluble aluminum powder baking paint with high gloss, good adhesion, good impact, high hardness, re-coating and low-temperature curing without additional catalyst can be prepared. The acrylic resin can be widely used in water-soluble aluminum powder baking paint.

Description

Technical Field

[0001] This invention relates to a low-temperature curing, high-performance, water-soluble acrylic resin for baking paint with aluminum powder, belonging to the field of polymer resin technology. Background Technology

[0002] Water-soluble acrylic resins for aluminum powder baking coatings use water as a solvent, which significantly reduces the VOC content of the coating. However, due to the inherent properties of water, the coating needs to be baked at high temperatures (130–160°C) for a relatively long time (20–40 minutes) to achieve the required performance. Otherwise, the recoating performance, adhesion, impact resistance, and other comprehensive mechanical properties will be poor.

[0003] This invention, through extensive experimental screening of acrylic monomers, initiators, the composition ratio of acrylic acid and methacrylic acid, and synthesis processes, has developed a water-soluble acrylic resin with high adhesion, impact resistance, high hardness, recoatability, and low-temperature curing (90-100℃ × 10 minutes) without the need for external catalysts. Summary of the Invention

[0004] Objective of the invention: By simultaneously using methacrylic acid and acrylic acid in a free radical polymerization process and controlling their ratio, while optimizing and adjusting the optimal acrylic monomer and reaction conditions, an acrylic resin for aluminum powder baking paint is obtained that exhibits high gloss, good adhesion, good impact resistance, high hardness, recoatability, and low-temperature curing without the need for an external catalyst. The aluminum powder paint produced by this invention can be widely used on various metal substrates and overcomes the shortcomings of existing technologies.

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

[0006] A low-temperature curing, high-performance, water-soluble acrylic resin for baking paint with aluminum powder is made from the following raw materials:

[0007] It is made of styrene, acrylic acid, methacrylic acid, butyl acrylate, hydroxyethyl acrylate, TBPIN (tert-butyl peroxide-3,5,5-trimethylhexanoate), ethylene glycol tert-butyl ether, ethanol, and isooctyl acrylate.

[0008] As a preferred embodiment, the low-temperature curing high-performance water-soluble acrylic resin for aluminum powder baking paint described above is made from the following raw materials by weight percentage:

[0009] Styrene 8-10%, acrylic acid 2-5%, methacrylic acid 2-5%, butyl acrylate 26%, hydroxyethyl acrylate 6-8%, TBPIN 1-2%, ethylene glycol tert-butyl ether 20-30%, ethanol 5-10%, isooctyl acrylate 10-15%.

[0010] As a preferred embodiment, the low-temperature curing high-performance water-soluble acrylic resin for aluminum powder baking paint described above is made from the following raw materials by weight percentage:

[0011] Styrene 10%, acrylic acid 4.5%, methacrylic acid 2.5%, butyl acrylate 26%, hydroxyethyl acrylate 6%, TBPIN 1%, ethylene glycol tert-butyl ether 30%, ethanol 5%, isooctyl acrylate 15%.

[0012] The preparation method of the low-temperature curing high-performance water-soluble acrylic resin for aluminum powder baking paint according to the present invention includes the following steps:

[0013] (1) Add ethylene glycol tert-butyl ether to the reaction apparatus and heat to 140-145℃;

[0014] (2) Styrene, acrylic acid, methacrylic acid, butyl acrylate, hydroxyethyl acrylate, isooctyl acrylate and part of the initiator TBPIN are mixed according to weight percentage and then added to the dropping tank;

[0015] (3) When the temperature of the reaction apparatus in step (1) reaches 140-145℃, add the mixture from step (2) dropwise. The mixture is added over 5 to 4 hours. After the mixture is added, keep it warm for 2 to 1 hour. Then add the remaining initiator and keep it warm for another 2 to 1 hour.

[0016] (4) After the heat preservation is completed, cool to 70-80℃, add ethanol, and stir evenly.

[0017] As a preferred embodiment, the above-described method for preparing a low-temperature curing, high-performance water-soluble acrylic resin for aluminum powder baking paint includes the following steps:

[0018] (1) Add 500g of ethylene glycol tert-butyl ether to the reaction apparatus and heat to 140-145℃;

[0019] (2) Mix 500g of styrene, 72g of acrylic acid, 40g of methacrylic acid, 440g of butyl acrylate, 100g of hydroxyethyl acrylate, 240g of isooctyl acrylate and 12g of initiator TBPIN, and add them to the dropping container.

[0020] (3) When the temperature of the reaction apparatus in step (1) reaches 145-140℃, add the mixed monomer and initiator from step (2) dropwise. After 5 hours, keep warm for 1 hour, add 2g of peroxide TBPIN, keep warm for another 1 hour, cool to 70-80℃, add 74g of ethanol, and stir evenly.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] Through extensive experimental data analysis and application, this invention utilizes acrylic acid and methacrylic acid simultaneously in free radical polymerization, adjusting their ratio to 1.8:1. This refines the selection of acrylic acid monomers and the synthesis process, resulting in a water-soluble acrylic resin that exhibits high gloss, good adhesion, good impact resistance, high hardness, recoatability, and low-temperature curing capability (90–100°C × 10 minutes). This overcomes the shortcomings of existing technologies that require high-temperature curing (130–160°C × 20–40 minutes) to meet performance requirements. Attached Figure Description

[0023] Figure 1 This is the structural formula of the acrylic resin of the present invention.

[0024] Figure 2 This is the structural formula of the acrylic resin of the present invention.

[0025] Figure 3 This is the structural formula of the acrylic resin of the present invention.

[0026] Figure 4 This is the structural formula of the acrylic resin of the present invention.

[0027] Figure 5 This is the structural formula of the acrylic resin of the present invention.

[0028] Figure 6 This is the structural formula of the acrylic resin of the present invention. Detailed Implementation

[0029] Example 1

[0030] 1. A method for preparing a high-performance water-soluble acrylic resin for aluminum powder baking paint, comprising the following steps:

[0031] (1) Add 500g of ethylene glycol tert-butyl ether to the reaction apparatus and heat to 140-145℃.

[0032] (2) Mix 500g of styrene, 72g of acrylic acid, 40g of methacrylic acid, 440g of butyl acrylate, 100g of hydroxyethyl acrylate, 240g of isooctyl acrylate and 12g of initiator TBPIN, and add them to the dropping container.

[0033] (3) When the temperature of the reaction apparatus in step (1) reaches 145-140℃, add the mixed monomer and initiator from step (2) dropwise. After 5 hours, keep warm for 1 hour, add 2g of peroxide TBPIN, keep warm for another 1 hour, cool to 70-80℃, add 74g of ethanol, and stir evenly.

[0034] 1. The acrylic resin prepared in Example 1 is mixed with aluminum powder and related additives according to the formula in Table 1, and then dispersed at high speed using a disperser to obtain aluminum powder baking paint. This process includes the following steps:

[0035] (1) Add ethylene glycol monobutyl ether, ethanol and dispersant to a disperser at 1000 rpm and stir until homogeneous.

[0036] (2) Add aluminum powder, reduce the speed to 500 rpm, and stir evenly.

[0037] (3) Add water-soluble acrylic resin, amino resin and methanol in sequence, and stir until uniform.

[0038] (4) Finally, add deionized water and DMEA, and stir until well combined.

[0039] Its performance is shown in Table 2.

[0040] Table 1. Composition of Aluminum Powder Baking Coating Formulation

[0041]

[0042]

[0043] Table 2. Results of paint film performance tests:

[0044] Gloss (20℃ / 60℃) 70 / 100 GB / T 9754-2007 Hardness (pencil scratch) 2H GB / T 6739-2006 Impact (direct impact) (kg.cm) 50 GB / T1732-93 Adhesion (circle test) Level 0 GB / T1720-79 Recoatability Level 1 Grid method MEK resistant wipe ≥100 times GB / T23989-79 .

[0045] Example 2

[0046] 1. A method for preparing an acrylic resin for water-soluble aluminum powder baking paint, comprising the following steps:

[0047] (1) Add 500g of ethylene glycol tert-butyl ether to the reaction apparatus and heat to 140-145℃.

[0048] (2) Mix 500g of styrene, 82g of acrylic acid, 30g of methacrylic acid, 440g of butyl acrylate, 100g of hydroxyethyl acrylate, 240g of isooctyl acrylate and 12g of initiator TBPIN, and add them to the dropping container.

[0049] (3) When the temperature of the reaction apparatus in step (1) reaches 145-140℃, add the mixed monomer and initiator from step (2) dropwise. After 5 hours, keep warm for 1 hour, add 2g of peroxide TBPIN, keep warm for another 1 hour, cool to 70-80℃, add 74g of ethanol, and stir evenly.

[0050] 2. Paint films were prepared using the same coating formulation and method as in Example 1, and their performance was tested as shown in Table 3 below.

[0051] Table 3 Results of Coating Film Performance Tests

[0052] Gloss (20℃ / 60℃) 57 / 95 GB / T 9754-2007 Hardness (pencil scratch) 2H GB / T 6739-2006 Impact (direct impact) (kg.cm) 40 GB / T1732-93 Adhesion (circle test) Level 2 GB / T1720-79 Recoatability Level 3 Grid method MEK resistant wipe ≥100 times GB / T23989-79 .

[0053] Example 3

[0054] 1. A method for preparing an acrylic resin for water-soluble aluminum powder baking paint, comprising the following steps:

[0055] (1) Add 500g of ethylene glycol tert-butyl ether to the reaction apparatus and heat to 140-145℃.

[0056] (2) Mix 500g of styrene, 52g of acrylic acid, 60g of methacrylic acid, 440g of butyl acrylate, 100g of hydroxyethyl acrylate, 240g of isooctyl acrylate and 12g of initiator TBPIN, and add them to the dropping container.

[0057] (3) When the temperature of the reaction apparatus in step (1) reaches 145-140℃, add the mixed monomer and initiator from step (2) dropwise. After 5 hours, keep warm for 1 hour, add 2g of peroxide TBPIN, keep warm for another 1 hour, cool to 70-80℃, add 74g of ethanol, and stir evenly.

[0058] 2. The same coating formulation and method as in Example 1 were used to prepare the paint film, and the performance test results are shown in Table 4 below.

[0059] Table 4 Results of Coating Film Performance Tests

[0060]

[0061]

[0062] Comparative Example 1

[0063] 1. The comparative method for preparing acrylic resin for water-soluble aluminum powder baking paint includes the following steps:

[0064] (1) Add 500g of ethylene glycol tert-butyl ether to the reaction apparatus and heat to 140-145℃.

[0065] (2) Mix 500g of styrene, 112g of acrylic acid, 440g of butyl acrylate, 100g of hydroxyethyl acrylate, 240g of isooctyl acrylate and 12g of initiator TBPIN, and add them to the dropping container.

[0066] (3) When the temperature of the reaction apparatus in step (1) reaches 145-140℃, add the mixed monomer and initiator from step (2) dropwise. After 5 hours, keep warm for 1 hour, add 2g of peroxide TBPIN, keep warm for another 1 hour, cool to 70-80℃, add 74g of ethanol, and stir evenly.

[0067] 2. The acrylic resin prepared in Comparative Example 1 was mixed with aluminum powder and related additives according to the formulation in Table 5, and the mixture was dispersed at high speed using a disperser to prepare aluminum powder baking paint using the same method as in Example 1. Its properties were tested and are shown in Table 6.

[0068] Table 5. Composition of Aluminum Powder Baking Coating Formulation

[0069] Example 1: Water-soluble acrylic resin 65 Ethylene glycol monobutyl ether 3 Amino resins 17 ethanol 1 methanol 1 aluminum powder 5 Dispersant D1900 (Puwei) 0.4 Deionized water 7 DMEA 0.6 Curing conditions 90℃ x 10 minutes

[0070] Table 6 Results of Coating Film Performance Tests

[0071] Gloss (20℃ / 60℃) 50 / 85 GB / T 9754-2007 Hardness (pencil scratch) HB GB / T 6739-2006 Impact (direct impact) (kg.cm) 30 GB / T1732-93 Adhesion (circle test) Level 4 GB / T1720-79 Recoatability Level 5 Grid method MEK resistant wipe ≤100 times GB / T23989-79 .

[0072] Comparative Example 1 shows that when methacrylic acid is not used in the formulation, under the same curing temperature conditions, its hardness, impact resistance, MEK wiping resistance and other properties are significantly reduced, which shows the rationality of the compatibility of the components of the present invention.

[0073] Furthermore, the comparative results of Examples 1, 2, and 3 show that changing the ratio of acrylic acid to methacrylic acid leads to a significant change in its performance, and the performance of Example 1 of the present invention is significantly better than that of Examples 2 and 3.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle 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 a low-temperature curing, high-performance water-soluble acrylic resin for aluminum powder baking paint, characterized in that, Includes the following steps: (1) Add 500g of ethylene glycol tert-butyl ether to the reaction apparatus and heat to 140-145℃; (2) Mix 500g of styrene, 72g of acrylic acid, 40g of methacrylic acid, 440g of butyl acrylate, 100g of hydroxyethyl acrylate, 240g of isooctyl acrylate and 12g of initiator TBPIN, and add them to the dropping container. (3) When the temperature of the reaction apparatus in step (1) reaches 145-140℃, add the mixed monomer and initiator from step (2) dropwise. After 5 hours, keep warm for 1 hour, add 2g of peroxide TBPIN, keep warm for another 1 hour, cool to 70-80℃, add 74g of ethanol, and stir evenly.

2. The application of the acrylic resin prepared by the method of claim 1 in the preparation of water-soluble aluminum powder baking paint.

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