Preparation method of high-performance peelable radix asparagi polyurea resin coating

Abstract

The invention discloses a preparation method of a high-performance peelable asparagus polyurea resin coating, and the high-performance peelable asparagus polyurea resin coating is prepared from the following raw materials in parts by weight: 40-50 parts of asparagus polyurea resin, 30-35 parts of an isocyanate curing agent, 3-6 parts of epoxy resin, 15-20 parts of a diluent, 0.2-0.8 part of a flatting agent and 0.2-0.8 part of a defoaming agent. Comprising the following steps: step 1, mixing the epoxy resin with a diluent to obtain a system 1; step 2, uniformly mixing and stirring asparagus polyurea resin, the system 1 and a diluent of the system 1 to obtain a system 2; step 3, adding the flatting agent and the defoaming agent into the system 2 obtained in the step 2 according to the proportion, and uniformly mixing and stirring to obtain a system 3; step 4, mixing an isocyanate curing agent with a diluent to obtain a system 4; and step 5, adding the system 4 into the system 3, and uniformly mixing and stirring to obtain the coating. The preparation method can be used for preparing the asparagus polyurea resin coating with high mechanical strength, weather resistance, low VOC (volatile organic compound) emission and controllable stripping performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, specifically to a method for preparing a high-performance peelable coating based on aspartame polyurea resin, which is suitable for the fields of metal surface protection, polyurethane coating protection, temporary protection and environmentally friendly coatings. Background Art

[0002] Many instruments, components, and other products are often susceptible to scratches and abrasion during transportation, storage, processing, and assembly. Environmental factors such as salt spray, moisture, acid rain, and microorganisms can also lead to chemical and electrochemical corrosion, significantly impacting the product's appearance and performance. To mitigate these damages and extend their service life, effective sealing and protection measures are crucial. Furthermore, many raw materials and semi-finished products must maintain a clean surface during subsequent processing or assembly, making traditional protective measures such as spraying anti-rust paint inappropriate. Since strippable coatings have no negative impact on the surface of the protected object, they have a wide range of applications, suitable for both indoor and outdoor protection of metal and non-metal materials, and for both short-term and long-term protection.

[0003] Therefore, the use of peelable coatings for protection has become an efficient and convenient solution to these problems. Traditional peelable coatings are made from ethanol, methanol, ethyl acetate, butyl acetate, polyvinyl butyral, n-butanol, and butanone. Polyvinyl butyral is modified to form a liquid protective coating, which is sprayed on the surfaces of objects such as automobiles, furniture, and electrical appliances as a protective coating. These coatings have excellent formability and can form a continuous, uniform, and tough transparent protective coating on complex surfaces. However, they generally suffer from insufficient mechanical properties (such as low tensile strength and easy breakage), poor weather resistance (such as salt spray resistance and short aging time), high VOC emissions, and unsatisfactory peel strength.

[0004] In existing technology, polyurea coatings utilize a one-time coating process, resulting in seamless joints regardless of surface area. Furthermore, they are dust-free materials and possess strong adhesion, friction resistance, and high hardness. For example, patent application 202311798263.7 discloses a method for synthesizing polyaspartic acid esters, their applications, and a polyurea coating. The process comprises the following steps: S1. Adding a dialkyl maleate dropwise to an alicyclic diamine at 40-60°C under a nitrogen atmosphere, incubating for 1-3 hours after the addition is complete; S2. Raising the temperature to 80-90°C and incubating for 24-48 hours. The solids content and residual primary amine content are then measured to obtain a primary product; S3. Further heating the primary product to 90-140°C, adding a lactone dropwise, and incubating for 6-12 hours. While polyurea coatings offer rapid curing properties, they struggle to balance strippability, environmental friendliness, and long-term protective properties.

[0005] Therefore, there is an urgent need for a peelable coating solution with excellent comprehensive performance, convenient construction and environmental protection. Summary of the Invention

[0006] In order to solve the problems of insufficient mechanical properties, environmental performance and poor temporary protection performance of traditional stripping coatings, the primary purpose of the present invention is to provide a method for preparing a high-performance strippable aspartame polyurea resin coating. The present invention can prepare an aspartame polyurea resin coating with high mechanical strength, weather resistance, low VOC emissions and controllable stripping performance, solving the problem of difficult balance between performance and environmental protection in the existing technology.

[0007] Another object of the present invention is to provide a method for preparing a high-performance strippable aspartame polyurea resin coating, wherein an aspartame polyurea resin and an isocyanate curing agent are reacted to form a coating, and an epoxy resin is added to ensure that the coating has high mechanical strength, weather resistance, low VOC emissions, and controllable stripping performance, and is easily stripped from metal aluminum substrates and polyurethane substrates without causing residue.

[0008] To achieve the above objectives, the technical solutions of the present invention are as follows.

[0009] A method for preparing a high-performance strippable aspartame polyurea resin coating, wherein the raw materials for preparing the coating include, in parts by mass (the parts indicated below are all parts by mass, and the usage ratio is also based on parts by mass), 40-50 parts of aspartame polyurea resin, 30-35 parts of isocyanate curing agent, 3-6 parts of epoxy resin, 15-20 parts of diluent, 0.2-0.8 parts of leveling agent, and 0.2-0.8 parts of defoaming agent; and the method comprises the following steps:

[0010] Step 1. Mixing and diluting the epoxy resin and its diluent to obtain system 1;

[0011] Step 2. After mixing and diluting the asparagine polyurea resin and its diluent, add it into system 1 and stir evenly to obtain system 2;

[0012] Step 3. Add the leveling agent and defoaming agent according to the ratio to the system 2 obtained in step 2, mix and stir evenly to obtain system 3;

[0013] Step 4. mixing the isocyanate curing agent and the diluent to obtain System 4;

[0014] Step 5. Add the system 4 to the system 3, mix and stir evenly to obtain the coating.

[0015] The present invention adopts asparagus polyurea resin as the main material, which has a high amine value, a long reaction time with an isocyanate curing agent, a suitable operating period, and has good adhesion to metal substrates and polyurethane substrates after adding a small amount of epoxy resin. After curing at room temperature, a thin film is formed and can be easily peeled off without residue. It has high mechanical strength and chemical resistance, has a good sealing effect on the substrate, and has a good temporary protection effect.

[0016] Furthermore, the epoxy resin is one or a mixture of two or more of E12, E15, E20, E35, E44, and E51. The diluent of the epoxy resin is any one or a combination of PMA and xylene.

[0017] Further, in step 2, the asparagus polyurea resin is specifically LR-1520, LR-1524, LR-2850, LR-1220, LR-1330, LR-1420, LR-6100, or a mixture of two or more thereof, and has an amine equivalent content of 130 to 500 g / mol and a viscosity of 100 to 700 mPa.s.

[0018] Furthermore, the amine equivalent content of the aspartame polyurea resin is 130-400 g / mol. If the amine equivalent is higher or lower than the above range, the paint film will dry too quickly or too slowly, making it difficult to peel off later.

[0019] Furthermore, in step 3, the leveling agent is selected from polyacrylate or polyether-modified polydimethylsiloxane. Specifically, the leveling agent is one or a mixture of two or more of BYK-310, BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-320, BYK358N, and Tego Glide 450.

[0020] Furthermore, the leveling agent is BYK358N type leveling agent, which can effectively reduce the surface tension of the two-component coating and enhance its wetting ability on the substrate surface, thereby avoiding shrinkage cavities and oil pits.

[0021] Furthermore, in step 3, the defoaming agent is one or a mixture of two or more of PA 240, PA 120, PA 318, MO 2100 AC, MO2134AC, BYK-088, and EFKA-2722.

[0022] Furthermore, the isocyanate curing agent is specifically one or a mixture of two or more of HT-100, HT-300, HT-400, HT-600, H-5112B, H-5113B, H-5114B, H-5115B, and H-5110B, and has an NCO content of 5-23% and a viscosity of 500-2000 mPa.s.

[0023] Furthermore, the mass of the isocyanate curing agent is 40-50 parts, at which weight the tensile strength, elongation at break and friction resistance are better.

[0024] Further, in the step 5, the mixing is uniform and fully matured, and then a diluent is added, and the mixing ratio between the asparagus polyurea resin, the isocyanate curing agent and the diluent is 50:35:15, 50:32:18, 49:35:16, 48:34:18, 47:38:15, and one of 46:36:18; the asparagus polyurea resin needs its own diluent to be diluted for standby use; the isocyanate curing agent also needs its own diluent to be diluted and then standby; in addition to the three diluent amounts added above, the remaining diluent needs to be used to make up the corresponding mass parts according to the above ratio, and the diluent is one or two of xylene, toluene, ethyl acetate, butyl acetate, and dearomatized solvent oil.

[0025] Furthermore, in step 1, the diluents of the epoxy resin are PMA and xylene, and their usage ratio is epoxy resin:PMA:xylene=80:8:12;

[0026] In step 2, the diluents of the aspartame polyurea resin are dearomatized solvent oil and ethyl acetate, wherein the amount of dearomatized solvent oil and ethyl acetate is dearomatized solvent oil:ethyl acetate=1:2;

[0027] In step 4, the diluent of the isocyanate curing agent is butyl acetate, and the usage ratio is isocyanate curing agent: butyl acetate = 90:10.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention adopts asparagus polyurea resin as the main material, has a long reaction time with the isocyanate curing agent, has a suitable operating period, and has good adhesion to metal substrates and polyurethane substrates after adding a small amount of epoxy resin. After curing at room temperature, a thin film is formed and can be easily peeled off without residue. It has high mechanical strength and chemical resistance, has a good sealing effect on the substrate, and has a good temporary protection effect.

[0030] The present invention uses asparagus polyurea resin and isocyanate curing agent to react to form a coating, which has high mechanical strength, weather resistance, low VOC emissions and controllable peeling performance, and is easy to peel off from metal aluminum substrates and polyurethane substrates without easily leaving residue. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Unless otherwise defined, all technical terms used hereinafter have the same meaning as those commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0032] First, the present invention provides a method for preparing a high-performance strippable aspartame polyurea resin coating. The raw materials for preparing the coating include, by weight, 40-50 parts of aspartame polyurea resin, 30-35 parts of isocyanate curing agent, 15-20 parts of diluent, 3-6 parts of epoxy resin, 0.2-0.8 parts of leveling agent, and 0.2-0.8 parts of defoaming agent; and the method comprises the following steps:

[0033] Step 1. Mixing and diluting the epoxy resin and its diluent to obtain system 1;

[0034] Step 2. After mixing and diluting the asparagine polyurea resin and its diluent, add it into system 1 and stir evenly to obtain system 2;

[0035] Step 3. Add the leveling agent and defoaming agent according to the proportion to the system obtained in step 2, mix and stir evenly to obtain system 3;

[0036] Step 4. mixing the isocyanate curing agent and its diluent to obtain System 4;

[0037] Step 5. Add the system 4 to the system 3, mix and stir evenly to obtain the coating.

[0038] On this basis, the method for preparing the strippable coating implemented by the present invention comprises the following steps:

[0039] S1. Substrate treatment: remove dust from the polyurethane-based surface; remove oil and dust from the aluminum-based and cold-rolled steel surfaces; remove dust from the glass surface.

[0040] S2. The epoxy resin and its diluent are mixed and stirred uniformly to obtain system 1.

[0041] S3. Mix and stir the asparagus polyurea resin and its diluent, then add it into system 1 and stir thoroughly to obtain system 2.

[0042] S4. Add the leveling agent and defoaming agent according to the proportion to the system obtained in step S3, mix and stir to obtain system 3.

[0043] S5. Mix the isocyanate curing agent and the diluent to obtain System 4.

[0044] S6. Add the system 4 obtained in step S5 to the system 3 obtained in step S4, mix and stir evenly and fully mature, then add a diluent to obtain system 5.

[0045] S7. Apply the system 5 obtained in step S6 on the four substrates described in S1 to obtain four peelable layers on different substrates.

[0046] S8. Physically peel off the peelable coating front side.

[0047] In step S2, the epoxy resin is one or a mixture of two or more of E12, E15, E20, E35, E44, and E51, and is sourced from Nantong Xingchen Chemical Materials Co., Ltd. The epoxy resin diluent is a combination of PMA and xylene, with a usage ratio of epoxy resin:PMA:xylene = 80:8:12.

[0048] In step S3, the asparagus polyurea resin is an asparagus polyurea resin produced by the applicant, specifically a mixture of one or two of LR-1520, LR-1524, LR-2850, LR-1220, LR-1330, LR-1420, and LR-6100, and any combination thereof, with an amine equivalent content of 130 to 500 g / mol, a viscosity of 100 to 700 mPa.s, and a mass of 40 to 50 parts.

[0049] In step S4, the leveling agent is one or two of BYK-310, BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-320, and Tego Glide 450, or any mixture thereof, with a mass of 0.2-0.8 parts. Among them, BYK-310, BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, and BYK-320 are from BYK of Germany, and Tego Glide 450 is from Digo.

[0050] In step S4, the defoaming agent is one or a mixture of two or more of PA 240, PA 120, PA 318, MO 2100 AC, MO 2134AC, BYK-088, and EFKA-2722, with a mass of 0.2-0.8 parts. PA 240, PA 120, PA 318, MO2100 AC, and MO 2134AC are from Foshan Jieke New Materials Co., Ltd., BYK-088 is from BYK of Germany, and EFKA-2722 is from Efka.

[0051] In step S5, the curing agent is an isocyanate curing agent, specifically one or two of HT-100, HT-300, HT-400, HT-600, H-5112B, H-5113B, H-5114B, H-5115B, H-5110B, and any mixture thereof, having an NCO content of 5-23%, a viscosity of 500-2000 mPa.s, and a mass of 30-35 parts.

[0052] In step S6, the mixture is stirred evenly and fully matured, and then a diluent is added. The mixing ratio between the asparagus polyurea resin, the isocyanate curing agent and the diluent is one of 50:35:15, 50:32:18, 49:35:16, 48:34:18, 47:38:15, and 46:36:18; wherein the asparagus polyurea resin needs to be diluted with its own diluent for standby use; the isocyanate curing agent also needs to be diluted with its own diluent and then set aside; in addition to the diluent amounts added in the first three, the remaining diluent needs to be filled with the corresponding mass parts according to the above ratio, and the diluent is any one or any two of xylene, toluene, ethyl acetate, butyl acetate, and dearomatized solvent oil.

[0053] The implementation of the present invention will be further described below with reference to specific embodiments.

[0054] Example 1.

[0055] Weigh 100 g of E44 epoxy resin, add 10 g of PMA and 15 g of xylene, mix and stir evenly to obtain System 1.

[0056] Weigh 562.5 g of LR-1520 and 562.5 g of LR-1330, mix and stir, add all of System 1, and weigh 70 g of diluent (the mass ratio of dearomatized solvent oil to ethyl acetate is 1:2), mix and stir evenly to obtain System 2;

[0057] Then weigh 4 g EFKA-2722 and 4 g BYK-306 and add them to system 2, mix and stir evenly to obtain system 3.

[0058] Weigh 300 g of H-5110B and 600 g of HT-600, add 100 g of butyl acetate, and mix and stir evenly to obtain System 4.

[0059] System 4 was added to system 3, mixed and matured first, and then 140 g of butyl acetate and 70 g of dearomatized solvent oil were weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 50:35:15) to obtain system 5.

[0060] System 5 was coated on the surface of aluminum plates and cured for 7 days to obtain a peelable coating on the surface of the aluminum plates.

[0061] Among them, the diluent is dearomatized solvent oil and ethyl acetate (mass ratio is 1:2); LR-1520 and LR-1330 are asparagus polyurea resins produced by the applicant, with amine equivalents of 305 g / mol and 320 g / mol respectively, and solid contents of 99.2% and 99.5% respectively, equivalent to OH contents of 5.8% and 6.2% respectively.

[0062] H-5110B is an isocyanate curing agent produced by the applicant, with an NCO content of 9% and a solid content of 99.2%; HT-600 is an isocyanate curing agent from Shandong Wanhua Chemical Co., Ltd., with an NCO content of 23%.

[0063] E44 comes from Nantong Xingchen Chemical Materials Co., Ltd., EFKA-2722 comes from Efka, and BYK-306 comes from BYK, Germany.

[0064] Example 2.

[0065] The specific steps are as in Example 1. 90 g of E44 epoxy resin was weighed, 8 g of PMA and 12 g of xylene were added, and the mixture was mixed and stirred to obtain System 1.

[0066] Weigh 480g of LR-2925, add all of System 1 into it, and weigh 60g of diluent (xylene and ethyl acetate), mix and stir evenly to obtain System 2;

[0067] Then weigh 6 g of leveling agent and 6 g of defoaming agent and add them to system 2, mix and stir evenly to obtain system 3.

[0068] Weigh 340 g of HT-100 and H-5114B (mass ratio 1.3:1), add diluent and mix well to obtain system 4.

[0069] System 4 was added to system 3, mixed and aged first, then xylene and ethyl acetate were weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 50:32:18) to obtain system 5.

[0070] System 5 was coated on the surface of aluminum plates and cured for 14 days to obtain a peelable coating on the surface of the aluminum plates.

[0071] The diluents are xylene and ethyl acetate, with a mass ratio of xylene:ethyl acetate = 2:1.

[0072] Among them, LR-2925 is our company's aspartame polyurea resin, with an amine equivalent of 1000 g / mol and a solid content of 65%.

[0073] H-5114B is our company's isocyanate curing agent with an NCO content of 7.1% and a solid content of 85%. HT-100 comes from Shandong Wanhua Chemical Co., Ltd. with an NCO content of 22%.

[0074] Example 3.

[0075] The specific steps are as in Example 1. 70 g of E44 epoxy resin was weighed, 7 g of PMA and 11.5 g of xylene were added, and the mixture was mixed and stirred to obtain System 1.

[0076] Weigh 490g of LR-1520 and LR-1420 (mass ratio 2:1), add all of System 1 into them, and weigh 75g of diluent, mix and stir evenly to obtain System 2;

[0077] Then weigh 4 g of leveling agent and 4 g of defoaming agent and add them to system 2, mix and stir evenly to obtain system 3.

[0078] Weigh 340 g of HT-300 and H-5113B (mass ratio 1.3:1), add diluent and mix well to obtain system 4.

[0079] System 4 was added to system 3, mixed and aged first, then xylene and butyl acetate were weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 49:35:16) to obtain system 5.

[0080] System 5 was coated on the polyurethane-based surface and cured for 7 days to obtain a peelable coating on the polyurethane-based surface.

[0081] The diluent is xylene and butyl acetate (mass ratio 1:1).

[0082] Among them, LR-1520 and LR-1420 are both our company's asparagus polyurea resins. The amine equivalent of LR-1520 is 305 g / mol, and the solid content is 99.2%, which is equivalent to an OH content of 5.8%. The amine equivalent of LR-1420 is 275 g / mol, and the solid content is 99.3%, which is equivalent to an OH content of 6%.

[0083] H-5113B is our company's isocyanate curing agent with an NCO content of 6% and a solid content of 99.5%; HT-300 comes from Shandong Wanhua Chemical Co., Ltd. with an NCO content of 20%.

[0084] Example 4.

[0085] The specific steps are as in Example 1. 80 g of E44 epoxy resin was weighed, 8 g of PMA and 12 g of xylene were added, and the mixture was mixed and stirred to obtain System 1.

[0086] Weigh 490g of LR-1220 and LR-1420 (mass ratio 2:1), add all of System 1 into them, and weigh 72g of diluent, mix and stir evenly to obtain System 2;

[0087] Then weigh 6 g of leveling agent and 5 g of defoaming agent and add them to system 2, mix and stir evenly to obtain system 3.

[0088] Weigh 340 g of HT-400 and H-5112B (mass ratio 1.2:1), add diluent and mix well to obtain system 4.

[0089] System 4 was added to system 3, mixed and aged first, then xylene and ethyl acetate were weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 48:34:18) to obtain system 5.

[0090] System 5 was coated on the polyurethane-based surface and cured for 14 days to obtain a peelable coating on the polyurethane-based surface.

[0091] The diluent is xylene and ethyl acetate (mass ratio 3:1).

[0092] Among them, LR-1220 and LR-1420 are our company's aspartame polyurea resins. LR-1220 has an amine equivalent weight of 255 g / mol and a solid content of 99.5%, equivalent to an OH content of 7.2%. LR-1420 has an amine equivalent weight of 275 g / mol and a solid content of 99.3%, equivalent to an OH content of 6%.

[0093] H-5112B is our company's isocyanate curing agent with an NCO content of 3.5% and a solid content of 60%; HT-400 comes from Shandong Wanhua Chemical Co., Ltd. with an NCO content of 21.5%.

[0094] Example 5.

[0095] The specific steps are as in Example 1. 100 g of E44 epoxy resin was weighed, 10 g of PMA and 15 g of xylene were added, and the mixture was mixed and stirred to obtain System 1.

[0096] Weigh 500g of LR-524 and LR-1220 (mass ratio 1.5:1), add all of System 1 into them, and weigh 80g of diluent, mix and stir evenly to obtain System 2;

[0097] Then weigh 3 g of leveling agent and 3 g of defoaming agent and add them to system 2, mix and stir evenly to obtain system 3.

[0098] Weigh 350 g of HT-100 and H-5112B (mass ratio 1:1), add diluent and mix well to obtain system 4.

[0099] System 4 was added to system 3, mixed and aged first, then butyl acetate was weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 47:38:15) to obtain system 5.

[0100] System 5 was coated on the surface of cold-rolled steel and cured for 7 days to obtain a peelable coating on the surface of the cold-rolled steel.

[0101] The diluent is butyl acetate.

[0102] Among them, LR-524 is our company's aspartame polyurea resin, with an amine equivalent weight of 375g / mol and a solid content of 99.5%, equivalent to an OH content of 6.6%. LR-1220 is our company's aspartame polyurea resin, with an amine equivalent weight of 255g / mol and a solid content of 99.5%, equivalent to an OH content of 7.2%.

[0103] HT-100 comes from Shandong Wanhua Chemical Co., Ltd., with an NCO content of 22%. H-5112B is our company's isocyanate curing agent, with an NCO content of 3.5% and a solid content of 60%.

[0104] Example 6.

[0105] The specific steps are as in Example 1. 80 g of E44 epoxy resin was weighed, 8 g of PMA and 12 g of xylene were added, and the mixture was mixed and stirred to obtain System 1.

[0106] Weigh 480g of LR-1330, add all of System 1 into it, and weigh 65g of diluent, mix and stir evenly to obtain System 2;

[0107] Then weigh 3 g of leveling agent and 3 g of defoaming agent and add them to system 2, mix and stir evenly to obtain system 3.

[0108] Weigh 330 g of HT-100 and H-5115B (mass ratio 1.5:1), add diluent and mix well to obtain system 4.

[0109] System 4 was added to system 3, mixed and aged first, then ethyl acetate and butyl acetate were weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 47:38:15) to obtain system 5.

[0110] System 5 was applied to the surface of cold-rolled steel and cured for 14 days to obtain a peelable coating on the surface of the cold-rolled steel.

[0111] The diluent is ethyl acetate and butyl acetate (mass ratio 2:1).

[0112] Among them, LR-1330 is the aspartame polyurea resin produced by the applicant.

[0113] HT-100 is an isocyanate curing agent from Shandong Wanhua Chemical Co., Ltd., and H-5115B is our company's isocyanate curing agent with an NCO content of 5% and a solid content of 90%.

[0114] Example 7.

[0115] The specific steps are as in Example 1. 80 g of E44 epoxy resin was weighed, 8 g of PMA and 12 g of xylene were added, and the mixture was mixed and stirred to obtain System 1.

[0116] Weigh 450g of LR-524 and LR-1520 (mass ratio 1:1), add all of System 1 into them, and weigh 65g of diluent, mix and stir evenly to obtain System 2;

[0117] Then weigh 4 g of leveling agent and 4 g of defoaming agent and add them to system 2, mix and stir evenly to obtain system 3.

[0118] Weigh 350 g of H-5110B and H-5112B (mass ratio 1:1), add diluent and mix well to obtain system 4.

[0119] System 4 was added to system 3, mixed and aged first, then dichloromethane and butyl acetate were weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 47:38:15) to obtain system 5.

[0120] System 5 was coated on the glass surface and cured for 7 days to obtain a peelable coating on the glass surface.

[0121] The diluent is dichloromethane and butyl acetate (mass ratio 2:1).

[0122] LR-524 and LR-1520 are asparagus polyurea resins produced by the applicant. H-5110B and H-5112B are isocyanate curing agents produced by our company.

[0123] Example 8.

[0124] The specific steps are as in Example 1. 60 g of E44 epoxy resin was weighed, 6 g of PMA and 9 g of xylene were added, and the mixture was mixed and stirred to obtain System 1.

[0125] Weigh 480g of LR-524 and LR-2925 (mass ratio 3:1), add all of System 1 into them, and weigh 65g of diluent, mix and stir evenly to obtain System 2;

[0126] Then weigh 3 g of leveling agent and 3 g of defoaming agent and add them to system 2, mix and stir evenly to obtain system 3.

[0127] Weigh 350 g of HT-400 and H-5115B (mass ratio 1.5:1), add diluent and mix well to obtain system 4.

[0128] System 4 was added to system 3, mixed and aged first, then dichloromethane and butyl acetate were weighed and mixed, and the mixture was stirred evenly (the mass ratio of aspartame polyurea resin, isocyanate curing agent and diluent was 50:32:18) to obtain system 5.

[0129] System 5 was coated on the glass surface and cured for 14 days to obtain a peelable coating on the glass surface.

[0130] The diluent is butyl acetate.

[0131] LR-524 and LR-2925 are asparagus polyurea resins produced by the applicant, HT-400 comes from Shandong Wanhua Chemical Co., Ltd., and H-5115B is the isocyanate curing agent of our company.

[0132] The compositions of the raw materials used in Examples 1-8 are shown in Table 1 in parts by mass.

[0133] Table 1: Composition of raw materials used in Examples 1-8 by weight

[0134]

[0135] Test example.

[0136] The test examples tested various properties of the strippable aspartame polyurea resin coatings obtained after curing for 7 days and 14 days on different substrate surfaces. The specific results are shown in Table 2.

[0137] Table 2: Test results of various properties of strippable aspartame polyurea resin coating

[0138]

[0139] Table 2 Test results description:

[0140] The adhesion performance and peelability of the paint films obtained in Examples 1-8 meet the requirements of mass production.

[0141] The paint films of Examples 1-8 had a surface drying time of approximately 30 minutes, a through drying time of ≤ 6 hours, and a minimum peeling time of more than 24 hours. The test method was based on GB / T 1728-2020.

[0142] The peel strength of Examples 1-2 was approximately 0.5 N / cm, that of Examples 3-4 was approximately 0.6-0.7 N / cm, that of Examples 5-6 was approximately 0.5 N / cm, and that of Examples 7-8 was approximately 0.4 N / cm. This indicates that longer curing time increases peel strength. Furthermore, peel strength varies between surfaces, with polyurethane surfaces exhibiting slightly greater strength than metal surfaces, while glass surfaces are the easiest to peel. Peel strength testing methods refer to GB / T 2792-2014.

[0143] In Examples 1-8, elongation at break and tensile strength were measured using a universal testing machine. The results indicate that tensile strength and elongation at break are independent of the substrate and are related to curing time. Curing for 14 days resulted in slightly higher tensile strength and slightly lower elongation at break than curing for 7 days. The universal testing machine was an Instron 6800 series, and the testing methods were based on GB / T 528-2009.

[0144] The salt spray resistance of the paint films in Examples 1-8 reached 300 hours. The test method was based on GB / T 10125-2021.

[0145] The abrasion resistance of the paint films in Examples 1-8 varied. Examples 1, 3, 5, and 7 exhibited approximately 2.5 hours of abrasion resistance, while Examples 2, 4, 6, and 8 exhibited approximately 3 hours of abrasion resistance. This is due to the increased hardness and improved abrasion resistance of the paint films after 14 days of curing compared to 7 days, but this also may reduce the film's elasticity. The films were abraded using a reciprocating friction machine. The upper pair consisted of a stainless steel pin with a diameter of 10 mm and the lower pair consisted of a square substrate with a length of 5 cm. The friction was dry friction. The test method followed GB / T 3960-2008.

[0146] In Examples 1-8, the QUV-A aging time of the paint films all reached 2000 hours. The test method was based on GB / T 16422.3-2022.

[0147] In Examples 1-8, the operable period of the two-component coatings after compounding is 30 minutes.

[0148] It can be seen from this that the present invention uses asparagus polyurea resin as the main ingredient, has a high amine value, a long reaction time with the isocyanate curing agent, and has a suitable operating period. In addition, epoxy resin is added during the production process, and has good adhesion to the metal substrate and the polyurethane substrate, so that after curing at room temperature, a thin film is formed and is easy to peel off without residue. It has high mechanical strength and chemical resistance, has a good sealing effect on the substrate, has a good temporary protection effect, is easy to peel off from the metal aluminum substrate and the polyurethane substrate, and is not easy to produce residue.

[0149] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance strippable aspartame polyurea resin coating, characterized in that The raw materials for preparing the coating include, by weight, 40-50 parts of aspartame polyurea resin, 30-35 parts of isocyanate curing agent, 3-6 parts of epoxy resin, 15-20 parts of diluent, 0.2-0.8 parts of leveling agent, and 0.2-0.8 parts of defoaming agent; and the coating comprises the following steps: Step 1. Mixing and diluting the epoxy resin and its diluent to obtain system 1; Step 2. After mixing and diluting the asparagine polyurea resin and its diluent, add it into system 1 and stir evenly to obtain system 2; Step 3. Add the leveling agent and defoaming agent according to the ratio to the system 2 obtained in step 2, mix and stir evenly to obtain system 3; Step 4. mixing the isocyanate curing agent and its diluent to obtain System 4; Step 5. Add the system 4 to the system 3, mix and stir evenly to obtain the coating.

2. The method for preparing the high-performance strippable aspartame polyurea resin coating according to claim 1, characterized in that The epoxy resin is one or a mixture of two or more of E12, E15, E20, E35, E44, and E51.

3. The method for preparing the high-performance strippable aspartame polyurea resin coating according to claim 1, characterized in that The diluent of the epoxy resin is any one or a combination of toluene, PMA and xylene.

4. The method for preparing the high-performance strippable asparagus polyurea resin coating according to claim 1, characterized in that In the step 2, the asparagus polyurea resin is specifically one or a mixture of two or more of LR-1520, LR-1524, LR-2850, LR-1220, LR-1330, LR-1420, and LR-6100, and has an amine equivalent content of 130 to 500 g / mol and a viscosity of 100 to 700 mPa.s.

5. The method for preparing the high-performance strippable aspartame polyurea resin coating according to claim 1, characterized in that In step 3, the leveling agent is polyacrylate or polyether-modified polydimethylsiloxane. Specifically, the leveling agent is one or a mixture of two or more of BYK-310, BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-320, BYK358N, and Tego Glide 450.

6. The method for preparing the high-performance strippable aspartame polyurea resin coating according to claim 5, wherein The leveling agent is BYK358N leveling agent.

7. The method for preparing the high-performance strippable aspartame polyurea resin coating according to claim 1, characterized in that In step 3, the defoaming agent is one or a mixture of two or more of PA 240, PA 120, PA 318, MO 2100 AC, MO 2134AC, BYK-088, and EFKA-2722.

8. The method for preparing the high-performance strippable aspartame polyurea resin coating according to claim 1, characterized in that The isocyanate curing agent is specifically one or a mixture of two or more of HT-100, HT-300, HT-400, HT-600, H-5112B, H-5113B, H-5114B, H-5115B, and H-5110B, and has an NCO content of 5-23% and a viscosity of 100-2000 mPa.s.

9. The method for preparing a high-performance strippable aspartame polyurea resin coating according to claim 1, wherein The asparagine polyurea resin needs to be diluted with any amount of diluent, and the isocyanate curing agent needs to be diluted with any amount of diluent; the diluent of the asparagine polyurea resin and the diluent of the isocyanate curing agent are included in the total amount of diluent, and the mixing ratio between the asparagine polyurea resin, the isocyanate curing agent and the diluent is one of 50:35:15, 50:32:18, 49:35:16, 48:34:18, 47:38:15, and 46:36:18; the diluent is one or two of xylene, toluene, ethyl acetate, butyl acetate, and dearomatized solvent oil.

10. The method for preparing a high-performance strippable aspartame polyurea resin coating according to claim 9, characterized in that: In step 1, the diluents for the epoxy resin are PMA and xylene, and their usage ratio is epoxy resin:PMA:xylene=80:8:12; In step 2, the diluents of the aspartame polyurea resin are dearomatized solvent oil and ethyl acetate, wherein the amount of dearomatized solvent oil and ethyl acetate is dearomatized solvent oil:ethyl acetate=1:2; In step 4, the diluent of the isocyanate curing agent is butyl acetate, and the usage ratio is isocyanate curing agent: butyl acetate = 90:10.

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