Oxime ammonia ester modified self-repairing high-gloss hydroxypropyl dispersion and preparation method thereof

Abstract

The invention discloses a preparation method of an oxime ammonia ester modified self-repairing high-gloss hydroxypropyl dispersion. The preparation method comprises the following steps: S1, preparing an oxime ammonia ester modified monomer; s2, adding a solvent into a reaction kettle, and dropwise adding the mixed monomer C, the prepolymer B and an initiator into the reaction kettle; mixing and dropwise adding the mixed monomer D, a carboxyl-containing monomer and an initiator into the reaction kettle; and cooling, adding a neutralizer, adding deionized water for dispersion, and finally preparing the oxime ammonia ester modified self-repairing high-gloss hydroxypropyl dispersion. According to the invention, a two-step method is adopted, a hydroxypropyl dispersion is synthesized in a self-emulsifying manner, and a self-made monomer containing an oxime urethane bond is added, so that the emulsion has a self-repairing capability, can be self-repaired when a workpiece is damaged, and also has high gloss, high weather resistance and excellent chemical resistance; the service time is prolonged, and the maintenance cost is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of chemical water-based coatings, and in particular to an oxime urethane modified self-repairing high-gloss hydroxypropyl dispersion and a preparation method thereof. Background Art

[0002] As people's environmental awareness increases, traditional solvent-based paints and resins are strictly restricted in the market due to their high VOC content, and the advantages of water-based paints are becoming more and more obvious. Water-based hydroxypropylene dispersions are more favored by the market because of their excellent gloss, excellent weather resistance, relatively low price, and better construction performance. Water-based hydroxypropylene dispersions are divided into two types: primary dispersions and secondary dispersions. The primary dispersions currently on the market use emulsion polymerization to add emulsifiers so that the emulsifiers remain in the emulsion, which reduces the water resistance and chemical resistance of the paint film, and the gloss of the paint film is low. Usually, secondary hydroxypropylene dispersions have high gloss and good chemical resistance, and are easy to construct, but have poor self-repairing ability and high maintenance costs for workpieces, especially in some places that are not conducive to maintenance construction, so it is urgent to make self-repairing emulsions.

[0003] The secondary dispersions on the market have excellent characteristics such as high gloss, good weather resistance, and easy construction. However, the water resistance and chemical resistance of the paint film need to be improved, and the self-healing ability is poor. Some people in the market have introduced disulfide bonds to make self-healing hydroxypropylene secondary dispersions, and some have used hydrogen bonds and large π bonds between molecules to make the emulsion have the ability to self-heal. The hydrogen bonds and disulfide bonds have low bond energy and are easily destroyed. The self-healing ability and stability are relatively poor. After the introduction of molecular chain segments, the resistance to the paint film is also improved to a low level. Therefore, the preparation of an emulsion with good stability, good resistance and strong self-healing ability is a new direction for market development. The dynamic oxime urethane bond, due to the high chemical bond energy, is not easily destroyed, has better stability, good resistance, and can achieve low-temperature self-healing. At the same time, the prepared emulsion has the characteristics of high gloss and long activation period, which can well adapt to solve market needs. Summary of the invention

[0004] The object of the present invention is to provide an oxime amine ester modified self-repairing high-gloss hydroxypropylene dispersion and a preparation method thereof, so as to solve one or more of the above-mentioned prior art problems.

[0005] On the one hand, the preparation method of the oxime amino ester modified self-repairing high-gloss hydroxypropyl dispersion provided by the present invention comprises the following steps:

[0006] Step S1, preparing an oxime urethane modified monomer;

[0007] Step S2, adding the solvent into the reaction kettle, mixing the mixed monomer C, prepolymer B and initiator and dropping them into the reaction kettle; mixing the mixed monomer D, carboxyl-containing monomer and initiator and dropping them into the reaction kettle; then cooling, adding a neutralizer, and then adding deionized water to disperse, and finally obtaining an oxime amine ester modified self-healing high-gloss hydroxypropyl dispersion.

[0008] In certain embodiments, step S1 is specifically:

[0009] A1. Preparation of prepolymer A: According to weight percentage, add 2-6 parts of isocyanate and 0.002-0.06 parts of hydroquinone into a reaction kettle, heat to 60°C, dropwise add 1-3 parts of (meth)acrylic acid hydroxyl monomer, react at 60°C for 3h, and discharge the material after the NCO is qualified;

[0010] A2. Preparation of prepolymer B: According to weight percentage, 3-10 parts of acetone, 2-6 parts of diacetyl oxime and 3-10 parts of prepolymer A are added into a reaction kettle, and the temperature is raised to 50° C. to react for 6 hours until the NCO reaction is complete. Then, the acetone is removed, 1-5 parts of PMA are added, stirred evenly, and poured out for standby use to obtain the oxime urethane modified monomer.

[0011] In certain embodiments, step S2 is specifically:

[0012] According to the weight percentage, 3-20 parts of solvent are added to the reaction kettle, the temperature is raised to 140-155°C, 10-30 parts of mixed monomer C and 2-15 parts of prepolymer B are mixed evenly, 2-10 parts of initiator are added and dripped for 3-5h, and the temperature is kept constant for 40min after the dripping is completed; 8-20 parts of mixed monomer D, 2-6 parts of carboxyl-containing monomer and 1-4 parts of initiator are made into a mixture and dripped for 1-2h, and the temperature is kept constant for 3h after the dripping is completed; then the mixture is cooled to 70-95°C, 2-10 parts of neutralizer are added, and then 300-700 parts of deionized water are added to disperse to obtain an oxime amine ester modified self-repairing high-gloss hydroxypropyl dispersion.

[0013] In certain embodiments, the solvent in step S2 is one or a mixture of butyl acetate, No. 100 solvent oil, No. 150 solvent oil, No. 200 solvent oil, isopropanol, n-butanol, ethylene glycol ethyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ether, and diethylene glycol butyl ether, preferably one or a mixture of No. 100 solvent oil, No. 150 solvent oil, ethylene glycol butyl ether, propylene glycol butyl ether, and propylene glycol methyl ether acetate.

[0014] In certain embodiments, the initiator in step S2 is one or a mixture of diisobutyl azodinitrile, benzoyl peroxide, di-tert-butyl peroxide, di-tert-amyl peroxide, tert-butyl perbenzoate, tert-amyl perbenzoate, tert-butyl peroxidized 2-ethylhexanoate, and tert-amyl peroxidized 2-ethylhexanoate, preferably tert-butyl peroxide or tert-amyl peroxide.

[0015] In certain embodiments, the mixed monomer C in step S2 is one or a mixture of methyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, styrene, acrylonitrile, acrylamide, N-hydroxymethyl (meth)acrylamide, glycidyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate, preferably one or a mixture of methyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, isobornyl (meth)acrylate, and styrene.

[0016] In certain embodiments, the mixed monomer D in step S2 is one or a mixture of methyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, styrene, acrylonitrile, acrylamide, N-hydroxymethyl (meth)acrylamide, glycidyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate, preferably one or a mixture of methyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, isobornyl (meth)acrylate, and styrene.

[0017] In certain embodiments, the carboxyl group-containing monomer in step S2 is acrylic acid or methacrylic acid.

[0018] In certain embodiments, the neutralizing agent in step S2 is one or a mixture of ammonia, triethylamine, dimethylethanolamine, triethanolamine, AMP-95, preferably dimethylethanolamine or triethanolamine; the degree of neutralization is 70%-150%, preferably 80%-120%.

[0019] In a second aspect, the oxime amino ester modified self-repairing high-gloss hydroxypropyl dispersion provided by the present invention is prepared by the following preparation method:

[0020] Step S1, preparing an oxime urethane modified monomer;

[0021] Step S2, adding the solvent into the reaction kettle, mixing the mixed monomer C, prepolymer B and initiator and dropping them into the reaction kettle; mixing the mixed monomer D, carboxyl-containing monomer and initiator and dropping them into the reaction kettle; then cooling, adding a neutralizer, and then adding deionized water to disperse, and finally obtaining an oxime amine ester modified self-healing high-gloss hydroxypropyl dispersion.

[0022] The present invention has the following beneficial effects:

[0023] (1) The present invention synthesizes a new functional monomer, using a hydroxyl group to first react with isocyanate to form half of the NCO group, and then reacting the remaining NCO group with the hydroxyl group in dimethylglyoxime to synthesize a new monomer containing a double bond at one end and an oxime group at the other end. The new monomer contains an oxime urethane bond and can provide self-healing properties. When cured with an isocyanate curing agent, the oxime group at the other end can also generate a new oxime urethane bond, thereby improving the self-healing ability of the paint film.

[0024] (2) The present invention adopts a two-step method to synthesize a hydroxypropylene dispersion by a self-emulsifying method, and adds a self-made monomer containing an oxime amine ester bond, so that the emulsion has a self-repairing ability and can self-repair when the workpiece is damaged. At the same time, it also has high gloss, high weather resistance and excellent chemical resistance; it prolongs the service life and effectively reduces the maintenance cost. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below through embodiments.

[0026] Example 1

[0027] This example is intended to demonstrate the preparation method of prepolymer A, as follows:

[0028] Add 100g of isophorone diisocyanate and 0.1g of hydroquinone into the reactor, heat to 60°C, drop 58.62g of hydroxyethyl methacrylate, react at 60°C for 3h, and discharge the material after the NCO test is qualified.

[0029] Example 2

[0030] This example is intended to demonstrate the preparation of prepolymer B, as follows:

[0031] Add 60g acetone and 30g dimethylglyoxime into the reactor, add 90g prepolymer A, heat to 50°C, react for 6h, and after the NCO test is qualified, remove the acetone in vacuum, add 30g PMA, stir evenly and discharge the material for use.

[0032] Example 3

[0033] This example aims to demonstrate the preparation method of the self-healing high-gloss hydroxy acrylate emulsion modified by adding 5% prepolymer B, as follows:

[0034] (1) Add 30g of propylene glycol butyl ether and 30g of No. 100 solvent oil to a reaction kettle, heat it to 140-150°C, and introduce nitrogen for 30 minutes; mix 40g of hydroxypropyl acrylate, 30g of methyl methacrylate, 60g of styrene, 20g of isobornyl methacrylate, 25g of isooctyl acrylate, 16g of prepolymer B and 3g of tert-amyl peroxide and stir evenly to prepare a mixed monomer. After the temperature reaches the reaction temperature, drip the mixed monomer into the reaction kettle at a uniform speed. The dripping time is controlled to be 4 hours. After the dripping is completed, keep the temperature at 140-150°C for 40 minutes;

[0035] (2) The product of the first step is kept at 140-150° C., 20 g of hydroxypropyl acrylate, 30 g of methyl methacrylate, 10 g of acrylic acid, 15 g of butyl acrylate, and 1.5 g of tert-amyl peroxide are mixed and stirred to obtain a mixed monomer, which is then added to the reactor at a uniform speed over 1 hour, and then 0.3 g of tert-amyl peroxide is added, and the mixture is kept at 140-150° C. for 3 hours;

[0036] (3) The reaction temperature was cooled to 95°C, 12.3 g of dimethylethanolamine was added to the reaction kettle, and the mixture was stirred for 40 min. 285 g of deionized water was added at 70-80°C under high-speed stirring. The water was added within 40 min. After the addition, the mixture was stirred for 1 h to obtain a milky white, blue-light oxime amino ester-modified self-healing high-gloss hydroxypropyl dispersion.

[0037] The dispersion has a solid content of 45%, a viscosity of 300-1500mpa.s, and is stable for 30 days when stored at 40°C. The acid value calculated by solid content is 28.84mgKOH / g, and the hydroxyl content calculated by solid content is 3.0%. The modified water-based hydroxypropene dispersion is matched with Bayer's Bayhydur2655 water-based isocyanate curing agent, baked at 70°C for 30min, the pencil hardness can reach H, the paint film adhesion is level 0, the impact resistance is 50kg, the gloss at 20° angle is 85 degrees, it can withstand 40°C water for 10 days, acid resistance for 100h, and neutral salt spray resistance for 150h. The board surface is flat, the activation period is up to 6h, and after scratching, it is cured at 50°C for 48h, and the self-repair rate is above 80%. It is suitable for the application of high-gloss self-repairing resin and bottom-to-bottom integrated resin.

[0038] Example 4

[0039] This example aims to demonstrate the preparation method of the oxime urethane modified self-healing high-gloss hydroxy acrylate emulsion with 10% prepolymer B added, as follows:

[0040] (1) Add 45g of propylene glycol butyl ether and 45g of No. 100 solvent oil to a reaction kettle, heat it to 140-150°C, and introduce nitrogen for 30 minutes; mix 60g of hydroxypropyl acrylate, 45g of methyl methacrylate, 90g of styrene, 30g of isobornyl methacrylate, 37.5g of isooctyl acrylate, 48g of prepolymer B and 4.5g of tert-amyl peroxide and stir evenly to prepare a mixed monomer. After the temperature reaches the reaction temperature, drip the mixed monomer into the reaction kettle at a uniform speed. The dripping time is controlled to be 4 hours. After the dripping is completed, keep the temperature at 140-150°C for 40 minutes;

[0041] (2) The product of the first step is kept at 140-150° C., 30 g of hydroxypropyl acrylate, 45 g of methyl methacrylate, 15 g of acrylic acid, 22.5 g of butyl acrylate, and 2.25 g of tert-amyl peroxide are mixed and stirred to obtain a mixed monomer, which is then added to the reactor at a uniform speed over 1 hour, and then 0.45 g of tert-amyl peroxide is added, and the mixture is kept at 140-150° C. for 3 hours;

[0042] (3) The reaction temperature was cooled to 95°C, 18.45 g of dimethylethanolamine was added to the reaction kettle, and the mixture was stirred for 40 min. 457.5 g of deionized water was added at 70-80°C under high-speed stirring. The water was added within 40 min. After the addition, the mixture was stirred for 1 h to obtain a milky white oxime amino ester-modified self-healing high-gloss hydroxypropyl dispersion.

[0043] The dispersion has a solid content of 45%, a viscosity of 500-1500mpa.s, and is stable for 30 days at 40°C. The acid value calculated by solid content is 27.19mgKOH / g, and the hydroxyl content calculated by solid content is 3.0%. The modified water-based hydroxypropene dispersion is matched with Bayer's Bayhydur2655 water-based isocyanate curing agent, baked at 70°C for 30min, the pencil hardness can reach H, the paint film adhesion is level 0, the impact resistance is 50kg, the gloss at 20° angle is 82 degrees, it can withstand 40°C water for 15 days, acid resistance for 120h, and neutral salt spray resistance for 200h. The board surface is flat, the activation period is 4h, and after scratching, it is cured at 50°C for 48h, and the self-repair rate is above 90%. It is suitable for the application of high-gloss self-repairing resin and bottom-to-bottom integrated resin.

[0044] Example 5

[0045] This example aims to demonstrate the preparation method of the oxime urethane modified self-healing high-gloss hydroxy acrylate emulsion with 20% prepolymer B added, as follows:

[0046] (1) Add 30g of propylene glycol butyl ether and 30g of No. 100 solvent oil to a reaction kettle, heat it to 140-150°C, and introduce nitrogen for 30 minutes; mix 40g of hydroxypropyl acrylate, 30g of methyl methacrylate, 60g of styrene, 20g of isobornyl methacrylate, 25g of isooctyl acrylate, 64g of prepolymer B and 4.5g of tert-amyl peroxide and stir evenly to prepare a mixed monomer. After the temperature reaches the reaction temperature, drip the mixed monomer into the reaction kettle at a uniform speed, and the dripping time is controlled to be 4 hours. After the dripping is completed, keep the temperature at 140-150°C for 40 minutes;

[0047] (2) The product of the first step is kept at 140-150° C., 20 g of hydroxypropyl acrylate, 30 g of methyl methacrylate, 10 g of acrylic acid, 15 g of butyl acrylate, and 1.5 g of tert-amyl peroxide are mixed and stirred to obtain a mixed monomer, which is then added to the reactor at a uniform speed over 1 hour, and then 0.3 g of tert-amyl peroxide is added, and the mixture is kept at 140-150° C. for 3 hours;

[0048] (3) The reaction temperature was cooled to 95°C, 12.3 g of dimethylethanolamine was added to the reaction kettle, and the mixture was stirred for 40 min. 340 g of deionized water was added at 70-80°C under high-speed stirring. The water was added within 40 min. After the addition, the mixture was stirred for 1 h to obtain a milky white, blue-light oxime amino ester-modified self-healing high-gloss hydroxypropyl dispersion.

[0049] The dispersion has a solid content of 45%, a viscosity of 1000-3000mpa.s, and is stable for 30 days at 40°C. The acid value calculated by solid content is 24.46mgKOH / g, and the hydroxyl content calculated by solid content is 3.0%. The modified water-based hydroxypropene dispersion is matched with Bayer's Bayhydur2655 water-based isocyanate curing agent, baked at 70°C for 30min, the pencil hardness can reach 2H, the paint film adhesion is level 0, the impact resistance is 40kg, the gloss at 20° angle is 78 degrees, it can withstand 40°C water for 20 days, acid resistance for 150h, and neutral salt spray resistance for 240h. The board surface is flat, the activation period is 2h, and after scratching, it is cured at 50°C for 48h, and the self-repair rate is above 95%. It is suitable for the application of high-gloss self-repairing resin and bottom-to-bottom integrated resin.

[0050] Example 6

[0051] This example is intended to demonstrate the preparation method of high gloss hydroxy acrylate emulsion, as follows:

[0052] (1) Add 30g of propylene glycol butyl ether and 30g of No. 100 solvent oil to a reaction kettle, heat it to 140-150°C, and introduce nitrogen for 30 minutes; mix 40g of hydroxypropyl acrylate, 46g of methyl methacrylate, 60g of styrene, 20g of isobornyl methacrylate, 25g of isooctyl acrylate and 3g of tert-amyl peroxide and stir evenly to prepare a mixed monomer, after the temperature rises to the reaction temperature, drip the mixed monomer into the reaction kettle at a uniform speed, the dripping time is controlled to be 4h, and after the dripping is completed, keep the temperature at 140-150°C for 40 minutes;

[0053] (2) The product of the first step is kept at 140-150° C., 20 g of hydroxypropyl acrylate, 30 g of methyl methacrylate, 10 g of acrylic acid, 15 g of butyl acrylate, and 1.5 g of tert-amyl peroxide are mixed and stirred to obtain a mixed monomer, which is then added to the reactor at a uniform speed over 1 hour, and then 0.3 g of tert-amyl peroxide is added, and the mixture is kept at 140-150° C. for 3 hours;

[0054] (3) The reaction mixture was cooled to 95° C., 12.3 g of dimethylethanolamine was added to the reaction kettle, and the mixture was stirred for 40 min. 285 g of deionized water was added at 70-80° C. under high-speed stirring. The water was added within 40 min. After the addition, the mixture was stirred for 1 h to obtain a milky white hydroxypropyl dispersion with a blue glow.

[0055] The dispersion has a solid content of 45%, a viscosity of 300-1200mpa.s, is stable after 40 days of storage at 40°C, has an acid value of 28.8mgKOH / g based on solid content, and a hydroxyl content of 2.89% based on solid content. The modified water-based hydroxypropene dispersion is matched with Bayer's Bayhydur2655 water-based isocyanate curing agent, baked at 70°C for 30min, and the pencil hardness can reach H, the paint film adhesion is level 0, the impact resistance is 50kg, the gloss at 20° angle is 85 degrees, it can withstand 40°C water for 5 days, acid resistance for 80h, and neutral salt spray resistance for 120h. The board surface is flat, the activation period is up to 6h, and after scratching, it is cured at 50°C for 48h, and the self-repair rate is above 20%. It is suitable for the application of high-gloss resin and bottom-to-bottom resin.

[0056] Example 7

[0057] This example is intended to demonstrate the preparation method of prepolymer A1, as follows:

[0058] Add 100g of hexamethylene diisocyanate and 0.1g of hydroquinone into the reactor, heat to 60°C, drop 77.4g of hydroxyethyl methacrylate, react at 60°C for 3h, and discharge the material after the NCO test is qualified.

[0059] Example 8

[0060] This example is intended to demonstrate the preparation method of prepolymer B1, as follows:

[0061] Add 50g acetone and 20g dimethylglyoxime into the reactor, add 54.4g prepolymer A1, heat to 50℃, react for 6h, and after the NCO test is qualified, remove the acetone in vacuo, add 19g PMA, stir evenly and discharge the material for later use.

[0062] Example 9

[0063] This example aims to demonstrate the preparation method of the oxime urethane modified self-healing high-gloss hydroxy acrylate emulsion with 10% prepolymer B1 added, as follows:

[0064] (1) Add 30g of propylene glycol butyl ether and 30g of No. 100 solvent oil to a reaction kettle, heat it to 140-150°C, and introduce nitrogen for 30 minutes; mix 35g of hydroxypropyl acrylate, 30g of methyl methacrylate, 60g of styrene, 20g of isobornyl methacrylate, 25g of isooctyl acrylate, 32g of prepolymer B1 and 3g of tert-amyl peroxide and stir evenly to prepare a mixed monomer. After the temperature reaches the reaction temperature, drip the mixed monomer into the reaction kettle at a uniform speed. The dripping time is controlled to be 4 hours. After the dripping is completed, keep the temperature at 140-150°C for 40 minutes;

[0065] (2) The product of the first step is kept at 140-150° C., 20 g of hydroxypropyl acrylate, 30 g of methyl methacrylate, 10 g of acrylic acid, 15 g of butyl acrylate, and 1.5 g of tert-amyl peroxide are mixed and stirred to obtain a mixed monomer, which is then added to the reactor at a uniform speed over 1 hour, and then 0.3 g of tert-amyl peroxide is added, and the mixture is kept at 140-150° C. for 3 hours;

[0066] (3) The reaction temperature was cooled to 95°C, 12.3 g of dimethylethanolamine was added to the reaction kettle, and the mixture was stirred for 40 min. 300 g of deionized water was added at 70-80°C under high-speed stirring. The water was added within 40 min. After the addition, the mixture was stirred for 1 h to obtain a milky white oxime amino ester-modified self-healing high-gloss hydroxypropyl dispersion.

[0067] The dispersion has a solid content of 45%, a viscosity of 500-1000mpa.s, and is stable for 30 days at 40°C. The acid value calculated by solid content is 27.67mgKOH / g, and the hydroxyl content calculated by solid content is 2.92%. The modified water-based hydroxypropene dispersion is matched with Bayer's Bayhydur2655 water-based isocyanate curing agent, baked at 70°C for 30 minutes, the pencil hardness can reach H, the paint film adhesion is level 0, the impact resistance is 60kg, the 20° angle gloss is 85 degrees, resistant to 40°C water for 7 days, acid resistance for 100 hours, and neutral salt spray resistance for 180 hours. The board surface is flat, the activation period is up to 4 hours, and after scratching, it is cured at 50°C for 48 hours, and the self-repair rate is above 75%. It is suitable for the application of high-gloss self-repairing resin and bottom-to-bottom integrated resin.

[0068] The test results of paint film performance are shown in the following table:

[0069]

[0070] As shown in the above table, Example 3, Example 4, Example 5, Example 6, and Example 9, the addition of oxime urethane modified prepolymer significantly improves the resistance of the paint film, and the self-repair rate is significantly improved. Therefore, the addition of oxime urethane modified prepolymer in the present invention can produce a hydroxy acrylate dispersion with high gloss, good resistance, and self-repairing performance.

[0071] In summary, the present invention has the following advantages:

[0072] (1) The present invention synthesizes a new functional monomer, using a hydroxyl group to first react with isocyanate to form half of the NCO group, and then reacting the remaining NCO group with the hydroxyl group in dimethylglyoxime to synthesize a new monomer containing a double bond at one end and an oxime group at the other end. The new monomer contains an oxime urethane bond and can provide self-healing properties. When cured with an isocyanate curing agent, the oxime group at the other end can also generate a new oxime urethane bond, thereby improving the self-healing ability of the paint film.

[0073] (2) The present invention adopts a two-step method to synthesize a hydroxypropylene dispersion by a self-emulsifying method, and adds a self-made monomer containing an oxime amine ester bond, so that the emulsion has a self-repairing ability and can self-repair when the workpiece is damaged. At the same time, it also has high gloss, high weather resistance and excellent chemical resistance; it prolongs the service life and effectively reduces the maintenance cost.

[0074] The above description is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, and these should also be regarded as within the scope of protection of the invention.

Claims

1. A method for preparing an oxime aminoester modified self-repairing high-gloss hydroxypropyl dispersion, characterized in that: The following steps are involved: Step S1, preparing an oxime urethane modified monomer; Step S2, adding the solvent into the reaction kettle, mixing the mixed monomer C, prepolymer B and initiator and dropping them into the reaction kettle; mixing the mixed monomer D, carboxyl-containing monomer and initiator and dropping them into the reaction kettle; then cooling, adding a neutralizer, and then adding deionized water to disperse, and finally obtaining an oxime amine ester modified self-healing high-gloss hydroxypropyl dispersion.

2. The method for preparing the oxime amine modified self-repairing high-gloss hydroxypropyl dispersion according to claim 1, characterized in that: Step S1 is specifically as follows: A1. Preparation of prepolymer A: According to weight percentage, add 2-6 parts of isocyanate and 0.002-0.06 parts of hydroquinone into a reaction kettle, heat to 60°C, dropwise add 1-3 parts of (meth)acrylic acid hydroxyl monomer, react at 60°C for 3h, and discharge the material after the NCO is qualified; A2. Preparation of prepolymer B: According to weight percentage, 3-10 parts of acetone, 2-6 parts of diacetyl oxime and 3-10 parts of prepolymer A are added into a reaction kettle, and the temperature is raised to 50° C. to react for 6 hours until the NCO reaction is complete. Then, the acetone is removed, 1-5 parts of PMA are added, stirred evenly, and poured out for standby use to obtain the oxime urethane modified monomer.

3. The method for preparing the oxime amine ester modified self-repairing high-gloss hydroxypropyl dispersion according to claim 1, characterized in that: Step S2 is specifically as follows: According to the weight percentage, 3-20 parts of solvent are added to the reaction kettle, the temperature is raised to 140-155°C, 10-30 parts of mixed monomer C and 2-15 parts of prepolymer B are mixed evenly, 2-10 parts of initiator are added and dripped for 3-5h, and the temperature is kept constant for 40min after the dripping is completed; 8-20 parts of mixed monomer D, 2-6 parts of carboxyl-containing monomer and 1-4 parts of initiator are made into a mixture and dripped for 1-2h, and the temperature is kept constant for 3h after the dripping is completed; then the mixture is cooled to 70-95°C, 2-10 parts of neutralizer are added, and then 300-700 parts of deionized water are added to disperse to obtain an oxime amine ester modified self-repairing high-gloss hydroxypropyl dispersion.

4. The method for preparing the oxime amino ester modified self-repairing high-gloss hydroxypropyl dispersion according to claim 3, characterized in that: In step S2, the solvent is one or a mixture of butyl acetate, No. 100 solvent oil, No. 150 solvent oil, No. 200 solvent oil, isopropyl alcohol, n-butanol, ethylene glycol ethyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ether, and diethylene glycol butyl ether, preferably one or a mixture of No. 100 solvent oil, No. 150 solvent oil, ethylene glycol butyl ether, propylene glycol butyl ether, and propylene glycol methyl ether acetate.

5. The method for preparing the oxime amine ester modified self-repairing high-gloss hydroxypropyl dispersion according to claim 3, characterized in that: In step S2, the initiator is one of diisobutylnitrile azodioxide, benzoyl peroxide, di-tert-butyl peroxide, di-tert-amyl peroxide, tert-butyl perbenzoate, tert-amyl perbenzoate, tert-butyl peroxide 2-ethylhexanoate, and tert-amyl peroxide 2-ethylhexanoate, or a mixture of several of them, preferably tert-butyl peroxide or tert-amyl peroxide.

6. The method for preparing the oxime amino ester modified self-repairing high-gloss hydroxypropyl dispersion according to claim 3, characterized in that: In step S2, the mixed monomer C is one or a mixture of methyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, styrene, acrylonitrile, acrylamide, N-hydroxymethyl (meth)acrylamide, glycidyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate, preferably one or a mixture of methyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, isobornyl (meth)acrylate, and styrene.

7. The method for preparing the oxime amino ester modified self-repairing high-gloss hydroxypropyl dispersion according to claim 3, characterized in that: In step S2, the mixed monomer D is one or a mixture of methyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, styrene, acrylonitrile, acrylamide, N-hydroxymethyl (meth)acrylamide, glycidyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate, preferably one or a mixture of methyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-butyl (meth)acrylate, isooctyl (meth)acrylate, isobornyl (meth)acrylate, and styrene.

8. The method for preparing the oxime amine ester modified self-repairing high-gloss hydroxypropyl dispersion according to claim 3, characterized in that: In step S2, the carboxyl group-containing monomer is acrylic acid or methacrylic acid.

9. The method for preparing the oxime amine ester modified self-repairing high-gloss hydroxypropyl dispersion according to claim 3, characterized in that: In step S2, the neutralizing agent is one or a mixture of ammonia water, triethylamine, dimethylethanolamine, triethanolamine, AMP-95, preferably dimethylethanolamine or triethanolamine; the neutralization degree is 70%-150%, preferably 80%-120%.

10. An oxime amine ester modified self-healing high-gloss hydroxypropyl dispersion prepared by the preparation method according to any one of claims 1 to 9.

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