A hydroxyl acrylate resin and a method for preparing the same

Abstract

This invention provides a method for preparing a hydroxy acrylate resin, the hydroxy acrylate resin obtained by this method, and a coating prepared from the hydroxy acrylate resin. The method includes the following step a) C n H 2n (a) OH)₂ is added to the reactor and heated to 50–100°C. Isocyanate-containing functional monomers are slowly added and reacted. After addition, the reaction continues until the NCO content is <0.1%. Cooling yields long-chain hydroxyl monomers. (b) Organic solvent is added to the reactor and the temperature is raised to reflux. Under an inert atmosphere, a mixture of acrylate monomers, acrylic monomers, styrene, long-chain hydroxyl monomers, and an initiator is added dropwise. The reaction temperature is 70–130°C, where n = 4–8, and the isocyanate-containing functional monomers contain carbon-carbon double bonds. Coatings prepared from this hydroxy acrylate resin exhibit excellent fast-drying properties, and the resulting coating film possesses excellent flexibility.

Description

Technical Field

[0001] This invention belongs to the field of polymer science, specifically relating to a method for preparing hydroxyacrylate resin, the hydroxyacrylate resin obtained by this method, and a coating prepared from the hydroxyacrylate resin. The coating formulated from the hydroxyacrylate resin exhibits excellent fast-drying properties, and the resulting coating film possesses excellent flexibility. Background Technology

[0002] With China's economic development and increased domestic consumption capacity, the market for Chinese-made vehicles is expanding, especially with the rapid development of electric vehicles. The increasing number of vehicles, coupled with faster road construction and a rise in accidents, has increased the demand for paint repair, particularly for quick-drying paints. However, current quick-drying repair paints often rely on expensive special isocyanate hardeners to provide fast drying, or use rigid resins to improve drying speed. These methods often result in insufficient flexibility, leading to risks such as cracking and poor impact resistance.

[0003] These factors have limited the development of the quick-repair paint market to some extent, and new raw materials need to be developed to further improve these conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a hydroxy acrylate resin and its preparation method.

[0005] This invention is achieved through the following technical solution:

[0006] According to a first aspect of the present invention, a method for preparing a hydroxyacrylate resin is provided, comprising the following steps:

[0007] a) The long-chain diol C n H 2n (OH)2 is added to the reactor and heated to 50-100°C. Functional monomers containing isocyanate groups are slowly added and reacted. After the addition is complete, the reaction continues until the NCO content is <0.1%. The mixture is then cooled to obtain long-chain hydroxyl monomers.

[0008] b) Add organic solvent to the reactor and heat to reflux. Under an inert atmosphere, add dropwise a mixture of acrylate monomers, acrylic monomers, styrene, long-chain hydroxyl monomers, and initiator. The reaction temperature is 70–130°C.

[0009] Among them, n = 4 to 8, and the functional monomers containing isocyanate groups contain carbon-carbon double bonds.

[0010] The molar ratio of the long-chain diol to the isocyanate-containing functional monomer is 1:0.9-1.

[0011] The mass ratio of acrylate monomer: acrylic monomer: styrene monomer: long-chain hydroxyl monomer: solvent is 25-50: 0.5-4: 4-20: 20-50: 20-40.

[0012] Preferably, the functional monomer containing the isocyanate group is one or more selected from ethyl isocyanate acrylate, ethyl isocyanate methacrylate and 2-(2-isocyanate ethoxy) ethyl methacrylate.

[0013] Preferably, the acrylic monomer is selected from one or more of acrylic acid and methacrylic acid.

[0014] Preferably, the acrylate monomer is selected from one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate and isobutyl methacrylate.

[0015] Preferably, the solvent is one or more of ethyl acetate, butyl acetate, sec-butyl acetate, toluene, and xylene.

[0016] The initiator is a free radical initiator. Preferably, the initiator is one or more selected from azobisisobutyronitrile, benzoyl peroxide, tert-butylperoxyneoptiyl, tert-butylperoxybenzyl and potassium persulfate.

[0017] Preferably, the mass ratio of the initiator to (monomer + solvent) is 0.5 to 4 to 100.

[0018] Preferably, in step b), the mixture is added dropwise over a period of 120 to 300 minutes, and the reaction is maintained at a constant temperature for 60 to 300 minutes.

[0019] According to a second aspect of the present invention, a hydroxy acrylate resin is provided, which is prepared by the method for preparing hydroxy acrylate resin according to the present invention.

[0020] According to a third aspect of the invention, a coating is provided comprising the hydroxy acrylate resin described in the invention.

[0021] Beneficial effects

[0022] The polyacrylate prepared by the method described in this invention introduces long chains and highly active hydroxyl groups. On the one hand, the highly active hydroxyl groups increase the drying rate of the paint film and achieve fast drying performance. On the other hand, the long chains improve the flexibility of the paint film, ensuring that the paint film is not easy to crack after drying and is more resistant to impact. Detailed Implementation

[0023] The following specific examples further illustrate the hydroxyl acrylate resin and its preparation method according to the present invention. It should be understood that the embodiments provided are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] The raw materials and their sources in this embodiment are as follows:

[0025] Acrylic acid monomers: Methacrylic acid - Wanhua Chemical, Acrylic acid - Alfa.

[0026] Acrylate monomers: methyl methacrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate-alfa.

[0027] Functional monomers containing isocyanates: ethyl isocyanate acrylate, ethyl isocyanate methacrylate, 2-(2-isocyanate ethoxy) ethyl methacrylate—adamas.

[0028] Initiators: azobisisobutyronitrile, benzoyl peroxide (aladdin); benzoyl peroxide, potassium persulfate (sigma-aldrich).

[0029] Solvents: Ethyl acetate, butyl acetate, sec-butyl acetate, toluene, xylene - Sinopec.

[0030] Example 1

[0031] a) Add 1180g (10mol) hexanediol to the reactor, heat to 70℃, slowly add 1410g (10mol) ethyl isocyanate acrylate to react, and react until the NCO content is <0.1% after the addition is completed. Cool and discharge to obtain long-chain hydroxy monomer I.

[0032] b) Add 100g of butyl acetate and 100g of xylene to the reactor, heat to reflux, and purge with nitrogen for protection. Add dropwise a mixture of 200g of methyl acrylate, 50g of butyl acrylate, 10g of acrylic acid, 40g of styrene, 500g of long-chain hydroxyl monomer I, and 40g of initiator azobisisobutyronitrile. The reaction temperature is 70℃, the dropwise addition time is 300min, the reaction is kept at this temperature for 60min, and then cooled and discharged.

[0033] Example 2

[0034] a) Add 1180g (10mol) hexanediol to the reactor, heat to 70℃, slowly add 1269g (9mol) ethyl isocyanate acrylate to react, and react until the NCO content is <0.1% after the addition is completed. Cool and discharge to obtain long-chain hydroxy monomer II.

[0035] b) Add 100g of butyl acetate and 100g of xylene to the reactor, heat to reflux, and purge with nitrogen for protection. Add dropwise a mixture of 200g of methyl acrylate, 50g of butyl acrylate, 10g of acrylic acid, 40g of styrene, 500g of long-chain hydroxyl monomer II, and 40g of initiator azobisisobutyronitrile. The reaction temperature is 70℃, the dropwise addition time is 300min, the reaction is kept at this temperature for 60min, and then cooled and discharged.

[0036] Example 3

[0037] a) Add 1460g (10mol) octanediol to the reactor, heat to 50°C, and slowly add 1470g (9.48mol) ethyl isocyanate methacrylate to react. After adding the material, react until the NCO content is <0.1%, cool and discharge to obtain long-chain hydroxy monomer III.

[0038] b) Add 200g of sec-butyl acetate and 100g of toluene to the reactor, heat to reflux, and purge with nitrogen for protection. Add dropwise a mixture of 200g of methyl methacrylate, 60g of butyl methacrylate, 40g of methacrylic acid, 200g of styrene, 200g of long-chain hydroxyl monomer III, and 20g of initiator benzoyl peroxide. The reaction temperature is 100℃, the dropwise addition time is 120min, the reaction is kept at this temperature for 300min, and then cooled and discharged.

[0039] Example 4

[0040] a) Add 900g (10mol) butanediol to the reactor, heat to 100℃, slowly add 1990g (10mol) 2-(2-isocyanate ethoxy) ethyl methacrylate and react until the NCO content is <0.1%, cool and discharge to obtain long-chain hydroxy monomer IV.

[0041] b) Add 300g xylene and 100g ethyl acetate to the reactor, heat to reflux, and purge with nitrogen for protection. Add dropwise a mixture of 200g methyl methacrylate, 100g ethyl methacrylate, 5g methacrylic acid, 40g styrene, 255g long-chain hydroxyl monomer IV, and 5g potassium persulfate initiator. The reaction temperature is 130℃, the dropwise addition time is 210min, the reaction is kept at this temperature for 180min, and then cooled and discharged.

[0042] Example 5

[0043] a) Add 900g (10mol) butanediol to the reactor, heat to 100℃, slowly add 1410g (10mol) ethyl isocyanate acrylate to react, and react until the NCO content is <0.1% after the addition is complete. Cool and discharge to obtain long-chain hydroxy mono-V.

[0044] b) Add 250g of butyl acetate to the reactor, heat to reflux, and purge with nitrogen for protection. Add dropwise a mixture of 400g of methyl acrylate, 100g of isobutyl acrylate, 5g of acrylic acid, 40g of styrene, 205g of long-chain hydroxyl monomer V, and 10g of initiator azobisisobutyronitrile. The reaction temperature is 80℃, the dropwise addition time is 210min, the reaction is kept at this temperature for 180min, and then cooled and discharged.

[0045] Comparative Example 1

[0046] Commercially available resin ACR6875 - Tongde Resin.

[0047] Comparative Example 2

[0048] 250g of butyl acetate was added to the reactor and heated to reflux. Nitrogen gas was introduced for protection. A mixture of 400g of methyl acrylate, 100g of isobutyl acrylate, 5g of acrylic acid, 40g of styrene, 205g of hydroxyethyl acrylate, and 10g of azobisisobutyronitrile (azobisisobutyronitrile) was added dropwise. The reaction temperature was 80℃, the dropwise addition time was 210min, the reaction was kept at this temperature for 180min, solvent was added, the mixture was cooled, and the product was discharged.

[0049] Comparative Example 3

[0050] a) Add 1180g (10mol) hexanediol to the reactor, heat to 70℃, slowly add 1130g (8mol) ethyl isocyanate acrylate to react, and react until the NCO content is <0.1% after the addition is complete. Cool and discharge to obtain long-chain hydroxyl monomer VI.

[0051] b) Add 100g of butyl acetate and 100g of xylene to the reactor, heat to reflux, and purge with nitrogen for protection. Add dropwise a mixture of 200g of methyl acrylate, 50g of butyl acrylate, 10g of acrylic acid, 40g of styrene, 500g of long-chain hydroxyl monomer VI, and 40g of initiator azobisisobutyronitrile. The reaction temperature is 70℃, the dropwise addition time is 300min, the reaction is kept at this temperature for 60min, and then cooled and discharged.

[0052] Comparative Example 4

[0053] a) Add 1180g (10mol) hexanediol to the reactor, heat to 70℃, slowly add 1550g (11mol) ethyl isocyanate acrylate to react, react until the NCO content is <0.1%, cool and discharge to obtain long-chain hydroxyl mono-VII;

[0054] b) Add 100g of butyl acetate and 100g of xylene to the reactor, heat to reflux, and purge with nitrogen for protection. Add dropwise a mixture of 200g of methyl acrylate, 50g of butyl acrylate, 10g of acrylic acid, 40g of styrene, 500g of long-chain hydroxyl monomer VII, and 40g of initiator azobisisobutyronitrile. The reaction temperature is 70℃, the dropwise addition time is 300min, the reaction is kept at this temperature for 60min, and then cooled and discharged.

[0055] The above-mentioned resin and curing agent are formulated into two-component varnishes according to the following formula, as shown in Table 1 below.

[0056] Table 1: Main Paint Components and Hardener Components

[0057]

[0058] Among them, HT-100 is an HDI trimer, manufactured by Wanhua Chemical.

[0059] IT-170B is an IPDI trimer, manufactured by Wanhua Chemical.

[0060] Additive TI is a dehydrating agent, Borchers.

[0061] The main paint component contains hydroxyl groups, while the curing agent component contains isocyanate groups. The coating is prepared by weighing the main paint component and the curing agent component in a molar ratio of NCO:OH of 1.2:1.

[0062] During testing, the main paint components and hardener were mixed evenly, allowed to stand for 15 minutes, and then the paint was applied at a ratio of 100g / m². 2 The coating was sprayed onto a tinplate that already had a primer, and performance tests were conducted.

[0063] Table 2: Performance test results of Examples 1-5 and Comparative Examples 1-4

[0064]

[0065] Surface drying time: When the paint film surface is lightly touched with a finger and no paint sticks to the finger, it is considered that the surface is dry. The time recorded is the surface drying time.

[0066] Finger-press drying time: Press the paint film surface firmly with your thumb. If no fingerprint or mark is left, the time recorded is the finger-press drying time.

[0067] Pencil hardness testing standard: GB / T 6739-2006;

[0068] Standard for pendulum stiffness testing: GB / T 1730-2007;

[0069] Flexibility testing standard: GB / T 6742-2007;

[0070] Impact testing standard: GB / T 1732-2020;

[0071] Adhesion test standard: GB / T 9286-2021;

[0072] Recoating refers to spraying another layer on top of the original coating and then testing the adhesion. This test examines the adhesion between the coatings and is more rigorous than the conventional adhesion test.

[0073] As shown in Table 2, Examples 1-5 exhibited excellent drying rate, flexibility, and impact resistance. Comparative Examples 1 and 2 showed average drying performance, as well as average flexibility and impact resistance. Comparative Example 3 had excessive small molecule alcohols, resulting in low drying performance. Comparative Example 4 contained excessive isocyanate-containing functional monomers, leading to excessive carbon-carbon double bonds and excessive cross-linking, resulting in a gel-like product that was unusable.

Claims

1. A method for preparing hydroxyacrylate resin, comprising the following steps: a) The long-chain diol C n H 2n (OH)2 is added to the reactor and heated to 50~100℃. Functional monomers containing isocyanate groups are slowly added and reacted. After the addition is completed, the reaction continues until the NCO content is <0.1%. The mixture is then cooled to obtain long-chain hydroxyl monomers. b) Add organic solvent to the reactor and heat to reflux. Under an inert atmosphere, add dropwise a mixture of acrylate monomers, acrylic monomers, styrene, long-chain hydroxyl monomers, and initiator. The reaction temperature is 70~130℃. In this case, n=4~8, and the functional monomers containing isocyanate groups contain carbon-carbon double bonds. The molar ratio of the long-chain diol to the isocyanate-containing functional monomer is 1:0.9~1. The mass ratio of acrylate monomer: acrylic monomer: styrene monomer: long-chain hydroxyl monomer: solvent is 25~50: 0.5~4: 4~20: 20~50: 20~40. The isocyanate-containing functional monomer is selected from one or more of ethyl isocyanate acrylate, ethyl isocyanate methacrylate, and 2-(2-isocyanate ethoxy)ethyl methacrylate.

2. The method for preparing hydroxyacrylate resin according to claim 1, wherein, The acrylic monomer is selected from one or more of acrylic acid and methacrylic acid.

3. The method for preparing hydroxyacrylate resin according to claim 1, wherein, The acrylate monomer is selected from one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, and isobutyl methacrylate.

4. The method for preparing hydroxyacrylate resin according to any one of claims 1 to 3, wherein, The solvent is one or more of ethyl acetate, butyl acetate, sec-butyl acetate, toluene, and xylene; and / or The initiator is a free radical initiator.

5. The method for preparing hydroxyacrylate resin according to any one of claims 1 to 3, wherein, The initiator is selected from one or more of azobisisobutyronitrile, benzoyl peroxide, tert-butylperoxyneoptiyl, tert-butylperoxybenzyl and potassium persulfate.

6. The method for preparing hydroxyacrylate resin according to any one of claims 1 to 3, wherein, The mass ratio of initiator to (monomer + solvent) is 0.5~4:

100.

7. The method for preparing hydroxyacrylate resin according to any one of claims 1 to 3, wherein, In step b), the mixture is added dropwise over a period of 120 min to 300 min, and the reaction is kept at a constant temperature for 60 min to 300 min.

8. A hydroxyacrylate resin prepared by the method according to any one of claims 1 to 7.

9. A coating comprising the hydroxy acrylate resin according to claim 8.

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