A weather-resistant self-cleaning self-stratification coating and a preparation method and application thereof

Abstract

The application relates to the paint technology field, and particularly discloses a weather-resistant self-cleaning self-stratification paint as well as a preparation method and application thereof. The application improves the film-forming property of the self-stratification paint, and adds a component with a toughening effect. After the weather-resistant self-cleaning self-stratification paint of the application is in contact with a carbon steel base, the formed coating is not prone to peeling and damage under external force, thereby overcoming the defect that the self-stratification paint with E44 epoxy resin as a main component has poor adhesion to some carbon steel bases, and the application is beneficial to the promotion and application of the self-stratification paint.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint, more particularly, it relates to a weather-resistant self-cleaning self-stratifying paint, a preparation method and application thereof. BACKGROUND

[0002] Paint is a viscous liquid prepared by using resin, or oil, or emulsion as the main component, adding or not adding pigments, fillers, and corresponding additives, and using organic solvents or water as the solvent. Traditional paint is mainly single-layer paint, that is, a single-layer coating is formed on the surface of the substrate after painting. However, due to the limited protection and decoration effect of single-layer paint, multiple layers of paint are often painted in actual construction, which not only has many construction procedures, but also requires a long construction time and relatively high cost, and the interlayer adhesion and service life still need to be improved. Self-stratifying paint is a new type of paint that appears to solve the above problems. Self-stratifying paint contains two or more incompatible components, and a multi-layer coating is formed by the self-separation of each component after one-time painting, which has broad development prospects.

[0003] In the related art, there is a self-stratifying paint including the following components by weight: 135 parts of hydroxyl-terminated polydimethylsiloxane, 225 parts of hydroxyl fluorocarbon resin, 72 parts of epoxy resin, 180 parts of curing agent, 103.5 parts of propylene glycol methyl ether acetate, and 180 parts of ethyl acetate. The preparation method of the self-stratifying paint is to mix the above components, stir and react at room temperature at a speed of 100 r / min for 60 min to obtain the self-stratifying paint.

[0004] For the related art in the above, the inventors believe that for the self-stratifying paint in the related art, although the epoxy resin has the ability to adhere to the metal substrate, the specific adhesion ability will vary with the types of the epoxy resin and the metal substrate. When E44 epoxy resin is selected as the main component of the epoxy resin, the self-stratifying paint in the related art is difficult to produce good adhesion effect on some types of carbon steel, and the adhesion of the formed coating is low, which is not conducive to the promotion and application of the self-stratifying paint. SUMMARY

[0005] When E44 epoxy resin is selected as the main component of the epoxy resin, the self-stratifying paint in the related art is difficult to produce good adhesion effect on some types of carbon steel, and the adhesion of the formed coating is low, which is not conducive to the promotion and application of the self-stratifying paint. In order to improve this defect, the present application provides a weather-resistant self-cleaning self-stratifying paint, a preparation method and application thereof.

[0006] In a first aspect, the present application provides a weather-resistant self-cleaning self-stratifying paint, which adopts the following technical solution:

[0007] A weather-resistant self-cleaning self-layering paint, comprising the following components in parts by weight: 100-105 parts of propylene glycol methyl ether acetate, 180-184 parts of ethyl acetate, 135-137 parts of hydroxyl-terminated polydimethylsiloxane, 225-230 parts of hydroxyl fluorocarbon resin, 72-74 parts of epoxy resin, 5-7 parts of carboxyl-terminated liquid butyl nitrile rubber, 0.8-2.4 parts of toughening aid, 2.5-4.5 parts of film-forming aid, 180-184 parts of curing agent, and 4.5-4.7 parts of catalyst; the epoxy resin comprises epoxy resin E44, the toughening aid comprises fluorinated graphene with a fluorination degree of 25-40%, and the film-forming aid comprises eucommia ulmoides gum.

[0008] By adopting the technical scheme, the carboxyl-terminated liquid butyl nitrile rubber, the fluorinated graphene, and the film-forming aid including the eucommia ulmoides gum are added in the formula of the self-layering paint. According to the compatibility among different components, when the self-layering paint is cured on the surface of the carbon steel substrate, the coating layer formed by the hydroxyl-terminated polydimethylsiloxane is located on the surface, the coating layer formed by the hydroxyl fluorocarbon resin is located in the middle, and the epoxy coating layer formed by the cured epoxy resin is located at the bottom. The epoxy coating layer is directly bonded with the carbon steel substrate, and the toughening aid represented by the fluorinated graphene, the film-forming aid represented by the eucommia ulmoides gum, and the carboxyl-terminated liquid butyl nitrile rubber are mainly distributed in the epoxy coating layer. During the curing process of the epoxy resin, the carboxyl-terminated liquid butyl nitrile rubber can precipitate a rubber phase, and the precipitated rubber phase cooperates with the fluorinated graphene and the eucommia ulmoides gum to produce a good toughening effect on the epoxy coating layer. In addition to the toughening effect, the eucommia ulmoides gum can also improve the film-forming effect of the epoxy resin, which is conducive to the full contact and combination of the epoxy coating layer with the carbon steel substrate. Based on the above reasons, after the weather-resistant self-cleaning self-layering paint is in contact with the carbon steel substrate, the coating layer formed thereby is not easy to be peeled off and damaged under external force, thereby overcoming the defect that the self-layering paint mainly composed of the E44 epoxy resin has a low adhesion to some carbon steel substrates, and facilitating the popularization and application of the self-layering paint.

[0009] Preferably, the epoxy resin further comprises a carboxylated epoxy resin, the weight of the carboxylated epoxy resin accounts for 18-32% of the total weight of the epoxy resin, and the carboxylated epoxy resin is prepared by the following method:

[0010] (1) under the condition of nitrogen protection, an NMP solution of E44 epoxy resin and an NMP solution of TDI are prepared, then the NMP solution of E44 epoxy resin is added into the NMP solution of TDI under the condition of nitrogen protection, stirred and reacted for 120-135 min, then heated to 60-65℃ and continuously stirred and reacted for 60-120 min, to obtain a TDI modified epoxy resin, which is ready for use; tartaric acid is dissolved in NMP to obtain an NMP solution of tartaric acid, which is ready for use; the weight ratio of TDI, tartaric acid and E44 epoxy resin is (0.8-1.6):(0.92-1.35):10;

[0011] (2) under the condition of nitrogen protection, the TDI modified epoxy resin is added into the NMP solution of tartaric acid, and dibutyltin dilaurate is added, and stirred and reacted for 120-135 min, then heated to 80-85℃ and continuously stirred and reacted for 120-135 min, then NMP is removed by evaporation under reduced pressure, to obtain a carboxylated epoxy resin.

[0012] By adopting the technical scheme, the E44 epoxy resin is first modified by using TDI as a medium, and isocyanate groups are introduced into the molecule of the E44 epoxy resin, then carboxyl groups are introduced by the reaction of the isocyanate groups with tartaric acid, to obtain a carboxylated epoxy resin. The carboxyl groups in the carboxylated epoxy resin can be chemically bonded to the surface of carbon steel, so that the adhesion of the coating layer formed by the self-layering coating is improved.

[0013] Preferably, the amount of the carboxylated epoxy resin accounts for 26-32% of the total weight of the epoxy resin.

[0014] By adopting the technical scheme, the amount of the carboxylated epoxy resin is preferably selected, which is helpful to improve the adhesion of the coating layer on the surface of the partial carbon steel substrate.

[0015] Preferably, the toughening aid further comprises modified fluorinated graphene, and the amount of the modified fluorinated graphene accounts for 28-50% of the total weight of the toughening aid, and the modified fluorinated graphene is prepared by the following method:

[0016] (1) 0.1-0.3 parts by weight of fluorinated graphene is added into deionized water for ultrasonic dispersion, to obtain a fluorinated graphene dispersion liquid, which is ready for use; 1.7-2.1 parts by weight of zinc nitrate hexahydrate, 1.0-1.2 parts by weight of aluminum nitrate nonahydrate and a certain amount of urea are dissolved in water to obtain a mixed solution, which is ready for use;

[0017] (2) the mixed solution is added into the fluorinated graphene dispersion liquid, and stirred and reacted at 95-100℃ for 10-12 h, to obtain modified fluorinated graphene.

[0018] By adopting the technical scheme, the application realizes the preparation of hydrotalcite by taking zinc nitrate hexahydrate, aluminum nitrate nonahydrate and urea as raw materials in the fluorinated graphene dispersion solution, realizes the compounding of the fluorinated graphene and the hydrotalcite, and obtains the modified fluorinated graphene. The compounding with the hydrotalcite can improve the dispersion effect of the fluorinated graphene, so that the modified fluorinated graphene can more fully play a toughening role in the epoxy coating, and helps to improve the adhesion of the coating on the surface of the partial carbon steel substrate.

[0019] Preferably, in the step (1) of preparing the modified fluorinated graphene, the amount of the fluorinated graphene is 0.1-0.2 parts by weight.

[0020] By adopting the technical scheme, the application optimizes the amount of the fluorinated graphene based on the preparation method of the modified fluorinated graphene, which helps to fully realize the modification of the fluorinated graphene.

[0021] Preferably, the amount of the modified fluorinated graphene accounts for 42-50% of the total weight of the toughening aid.

[0022] By adopting the technical scheme, the application optimizes the amount of the fluorinated graphene, which helps to improve the adhesion of the coating on the surface of the partial carbon steel substrate.

[0023] Preferably, the film-forming aid further comprises modified guttapercha, and the amount of the modified guttapercha accounts for 20-35% of the total weight of the film-forming aid. The modified guttapercha is prepared by the following method:

[0024] The guttapercha is added into petroleum ether and heated and dissolved to obtain a guttapercha petroleum ether solution. Water is added to the guttapercha petroleum ether solution under heat preservation conditions. Formic acid and hydrogen peroxide are added to the guttapercha petroleum ether solution after 90-100 minutes. The reaction is continued for 120-130 minutes to obtain a reaction product which is washed with alcohol. The product is vacuum dried to obtain the modified guttapercha. The weight ratio of the guttapercha, the formic acid and the hydrogen peroxide is 20:(6-7):(32-35).

[0025] By adopting the technical scheme, the application performs epoxidation treatment on the guttapercha to obtain modified guttapercha with epoxy groups. The modified guttapercha can be cured together with the epoxy resin and combined through chemical bonds, which can have a good toughening effect on the epoxy resin and help to improve the adhesion of the coating on the surface of the partial carbon steel substrate.

[0026] Preferably, the amount of the modified guttapercha accounts for 28-35% of the total weight of the film-forming aid.

[0027] By adopting the technical scheme, the application optimizes the amount of the modified guttapercha, which helps to improve the adhesion of the coating on the surface of the partial carbon steel substrate.

[0028] In a second aspect, the application provides a preparation method of the weather-resistant self-cleaning self-layering coating, which adopts the following technical scheme.

[0029] A preparation method of the weather-resistant self-cleaning self-layering coating, comprising the following steps:

[0030] (1) mixing propylene glycol methyl ether acetate and ethyl acetate to obtain a solvent; mixing hydroxyl-terminated polydimethylsiloxane, hydroxyl fluorocarbon resin, a curing agent and an epoxy resin to obtain a film-forming component; mixing carboxyl-terminated liquid nitrile rubber, a toughening aid, a film-forming aid and a catalyst to obtain an auxiliary component;

[0031] (2) mixing the auxiliary component into the solvent and heating and stirring, then adding the film-forming component and continuing to stir to obtain the weather-resistant self-cleaning self-layering coating.

[0032] By adopting the above technical scheme, the weather-resistant self-cleaning self-layering coating is obtained by first preparing the solvent, the film-forming component and the auxiliary component respectively, then dispersing the auxiliary component into the solvent, and finally adding the film-forming component.

[0033] In a third aspect, the application provides an application of the weather-resistant self-cleaning self-layering coating, which adopts the following technical scheme.

[0034] The application of the weather-resistant self-cleaning self-layering coating comprises spraying or rolling the weather-resistant self-cleaning self-layering coating onto a substrate and baking and curing at 180-245°C for 3-30min.

[0035] By adopting the above technical scheme, under the baking and curing conditions, the weather-resistant self-cleaning self-layering coating of the application can form a three-layer structure with an epoxy coating as the bottom layer, a hydroxyl fluorocarbon resin as the middle layer and a hydroxyl-terminated polydimethylsiloxane as the surface layer, and the self-layering coating is formed.

[0036] In summary, the application has the following beneficial effects:

[0037] 1. The application improves the film-forming property of the self-layering coating and adds a component with toughening effect. After the weather-resistant self-cleaning self-layering coating of the application contacts the carbon steel substrate, the formed coating is not easy to peel off and damage under external force, thereby overcoming the defect that the self-layering coating with E44 epoxy resin as the main component has poor adhesion to part of the carbon steel substrate, and facilitating the popularization and application of the self-layering coating.

[0038] 2. In the application, carboxyl groups are introduced into the E44 epoxy resin to obtain a carboxylated epoxy resin. The carboxyl groups in the carboxylated epoxy resin can chemically bond with the surface of the carbon steel, thereby improving the adhesion of the self-layering coating formed on the surface of part of the carbon steel substrate.

[0039] 3、The application realizes the compounding of fluorinated graphene and hydrotalcite, and obtains modified fluorinated graphene. The compounding with hydrotalcite can improve the dispersion effect of fluorinated graphene, so that the modified fluorinated graphene can more fully play a toughening role in the epoxy coating, and help to improve the adhesion of the coating on the surface of the carbon steel substrate. DETAILED DESCRIPTION

[0040] The application will be further described in detail below in combination with examples, preparation examples and comparative examples. The raw materials involved in the application can be obtained by market purchase.

[0041] The following is an example of preparing a carboxylated epoxy resin.

[0042] Preparation Example 1

[0043] In this preparation example, the carboxylated epoxy resin is prepared according to the following method:

[0044] (1) An NMP (N-methyl pyrrolidone, same below) solution of E44 epoxy resin (mass concentration of 0.2 g / mL) and an NMP solution of TDI (mass concentration of 0.03 g / mL) were prepared under nitrogen protection, then the NMP solution of E44 epoxy resin was added into the NMP solution of TDI under nitrogen protection, stirred and reacted for 120 min (referred to as the first stirring time in Table 1), then heated to 60°C (referred to as the first heating temperature in Table 1) and continued to stir and react for 60 min (referred to as the second stirring time in Table 1), to obtain a TDI modified epoxy resin, which was prepared for use; tartaric acid was dissolved in NMP to obtain an NMP solution of tartaric acid (mass concentration of 0.025 g / mL), which was prepared for use; in this step, the weight ratio of TDI, tartaric acid and E44 epoxy resin (referred to as the raw material ratio in Table 1) was 0.8:0.92:10;

[0045] (2) The TDI modified epoxy resin was added into the NMP solution of tartaric acid under nitrogen protection, 5‰ of dibutyltin dilaurate based on the weight of E44 epoxy resin was added, and stirred and reacted for 120 min (referred to as the third stirring time in Table 1), then heated to 80°C (referred to as the second heating temperature in Table 1) and continued to stir and react for 120 min (referred to as the fourth stirring time in Table 1), then NMP was removed by evaporation under reduced pressure, to obtain a carboxylated epoxy resin.

[0046] As shown in Table 1, the differences between Preparation Examples 1-5 lie in the different raw material ratios and production and processing parameters of the carboxylated epoxy resin.

[0047] Table 1 Raw material ratio and production and processing parameters of carboxylated epoxy resin

[0048] Sample Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 Raw material ratio 0.8:0.92:10 0.82:0.98:10 0.85:1.07:10 0.88:1.22:10 0.92:1.35:10 First stirring time / min 120 124 128 132 135 First heating temperature / ℃ 60 61 62 64 65 Second stirring time / min 60 70 80 100 120 Third stirring time / min 120 124 128 132 135 Second heating temperature / ℃ 80 81 82 84 85 Fourth stirring time / min 120 124 128 132 135

[0049] Preparation Example of Modified Fluorinated Graphene

[0050] The following is illustrated by taking Preparation Example 6 as an example.

[0051] Preparation Example 6

[0052] In this preparation example, the modified fluorinated graphene is prepared according to the following method:

[0053] (1) 0.1 kg of fluorinated graphene is added into 10 kg of deionized water for ultrasonic dispersion to obtain a fluorinated graphene dispersion solution, which is prepared for use; 1.7 kg of zinc nitrate hexahydrate, 1.0 kg of aluminum nitrate nonahydrate and a certain amount of urea are dissolved in water to obtain a mixed solution, which is prepared for use; in this step, n(urea):n(Al)+n(Zn)=3, and the sum of the concentrations of Zn and Al in the mixed solution is 0.15 mol / L;

[0054] (2) The mixed solution is added into the fluorinated graphene dispersion solution, and stirred at 95°C (referred to as reaction temperature in Table 2) for 10 h (referred to as reaction time in Table 2) to obtain the modified fluorinated graphene.

[0055] As shown in Table 2, the differences between Preparation Examples 6-14 lie in the different raw material ratios and production and processing parameters of the modified fluorinated graphene.

[0056] Table 2 Raw material ratios and production and processing parameters of fluorinated graphene

[0057]

[0058] Preparation Example of Modified Gutta-Percha

[0059] The following is illustrated by taking Preparation Example 15 as an example.

[0060] Preparation Example 15

[0061] In this preparation example, the gutta-percha used is purified by being dissolved in petroleum ether and precipitated in anhydrous ethanol in advance.

[0062] In this preparation example, the modified gutta-percha is prepared according to the following method:

[0063] 1 kg of gutta-percha is added into 15 L of petroleum ether and heated to dissolve under the condition of a constant temperature water bath at 50°C to obtain a gutta-percha petroleum ether solution, 8 L of water is added into the gutta-percha petroleum ether solution under the condition of heat preservation, and after 90 min (referred to as first heat preservation time in Table 3), formic acid and hydrogen peroxide with a mass concentration of 30% are added into the gutta-percha petroleum ether solution, and the reaction is continued for 120 min (referred to as second heat preservation time in Table 1) under the condition of heat preservation to obtain a reaction product which is washed with alcohol, and the product is vacuum dried to obtain the modified gutta-percha; in this preparation example, the weight ratio of gutta-percha, formic acid and hydrogen peroxide is 20:6:32.

[0064] Table 3 shows that the different between Preparation Examples 15-19 is that the raw material ratio and production processing parameters of modified gutta-percha are different.

[0065] Table 3 shows that the different between Preparation Examples 15-19 is that the raw material ratio and production processing parameters of modified gutta-percha are different.

[0066]

[0067] Examples

[0068] Examples 1-5

[0069] The following is illustrated by taking Example 1 as an example.

[0070] Example 1

[0071] The present embodiment provides a weather-resistant self-cleaning self-layering coating, which comprises the following components: 10 kg of propylene glycol methyl ether acetate, 18 kg of ethyl acetate, 13.5 kg of hydroxyl-terminated polydimethylsiloxane, 22.5 kg of hydroxyl fluorocarbon resin, 7.2 kg of epoxy resin, 0.5 kg of carboxyl-terminated liquid nitrile rubber, 0.08 kg of toughening aid, 0.25 kg of film-forming aid, 18 kg of curing agent, and 0.45 kg of catalyst; the epoxy resin is epoxy resin E44, the toughening aid is fluorinated graphene with a fluorination degree of 25%, the film-forming aid is gutta-percha, which is previously dissolved in petroleum ether and precipitated in anhydrous ethanol (dissolution and precipitation are repeated three times) to achieve purification, the curing agent is cyanate CYMEL 325 curing agent, and the catalyst is King's NACURE 2107 catalyst; the hydroxyl value of the hydroxyl fluorocarbon resin is 60 mgKOH / g, and the chemical formula of the hydroxyl-terminated polydimethylsiloxane is R(SiMe2O) n (CH2) m CH2OH, wherein n = 15, m = 6, and R = -(CH2)6CH2OH.

[0072] The present embodiment also provides a preparation method of a weather-resistant self-cleaning self-layering coating, which comprises the following steps:

[0073] (1) mixing propylene glycol methyl ether acetate and ethyl acetate to obtain a solvent; mixing hydroxyl-terminated polydimethylsiloxane, hydroxyl fluorocarbon resin, curing agent, and epoxy resin to obtain a film-forming component; and mixing carboxyl-terminated liquid nitrile rubber, toughening aid, film-forming aid, and catalyst to obtain an auxiliary component;

[0074] (2) mixing the auxiliary component into the solvent, heating under the condition of a constant-temperature water bath at 50°C, and stirring at a speed of 100 r / min until the gutta-percha is completely dissolved, then adding the film-forming component, and continuing to stir for 60 min to obtain a weather-resistant self-cleaning self-layering coating.

[0075] The embodiment also provides an application of the weather-resistant self-cleaning self-layering coating, which comprises spraying or rolling the weather-resistant self-cleaning self-layering coating on a substrate, and baking and curing at 180 DEG C for 3 min, wherein the substrate is 907A carbon steel.

[0076] As shown in Table 4, the differences between Examples 1-5 mainly lie in the raw material proportions and baking and curing conditions of the self-layering coatings.

[0077] Sample Example 1 Example 2 Example 3 Example 4 Example 5 Propylene glycol methyl ether acetate / kg 10 10.1 10.2 10.4 10.5 Ethyl acetate / kg 18 18.1 18.2 18.3 18.4 Hydroxyl-terminated polydimethylsiloxane / kg 13.5 13.55 13.6 13.65 13.7 Hydroxyl fluorocarbon resin / kg 22.5 22.6 22.8 22..9 23 Epoxy resin / kg 7.2 7.25 7.3 7.35 7.4 Carboxyl-terminated liquid nitrile rubber / kg 0.5 0.55 0.6 0.65 0.7 Toughening aid / kg 0.08 0.12 0.16 0.2 0.24 Film-forming aid / kg 0.25 0.3 0.35 0.4 0.45 Curing agent / kg 18 18.1 18.2 18.3 18.4 Catalyst / kg 0.45 0.455 0.46 0.465 0.47 Fluorinated graphene fluorination degree / % 25 28 32 35 40 Baking time / min 3 10 16 22 30 Baking temperature / ℃ 180 195 216 230 245

[0078] Example 6

[0079] The difference between the embodiment and Example 5 lies in that the epoxy resin is composed of E44 epoxy resin and the carboxylated epoxy resin of Preparation Example 1, and the weight of the carboxylated epoxy resin accounts for 18% of the total weight of the epoxy resin (referred to as the carboxylated epoxy resin proportion in Table 6).

[0080] As shown in Table 5, the differences between Examples 6-10 lie in the Preparation Examples of the carboxylated epoxy resin.

[0081] Table 5 Preparation Examples of the carboxylated epoxy resin

[0082]

[0083]

[0084] As shown in Table 6, the differences between Examples 10-14 lie in the carboxylated epoxy resin proportions.

[0085] Table 6 Carboxylated epoxy resin proportions

[0086] Sample Carboxylated epoxy resin ratio / % Example 10 18 Example 11 22 Example 12 26 Example 13 28 Example 14 32

[0087] Example 15

[0088] The difference between the embodiment and Example 14 lies in that the toughening aid is composed of fluorinated graphene and the modified fluorinated graphene of Preparation Example 6, and the amount of the modified fluorinated graphene accounts for 28% of the total weight of the toughening aid (referred to as the modified fluorinated graphene proportion in Table 8).

[0089] As shown in Table 7, the differences between Examples 15-23 lie in the Preparation Examples of the modified fluorinated graphene.

[0090] Table 7 Preparation Examples of the modified fluorinated graphene

[0091] Sample Preparation Example Sample Preparation Example Example 15 Preparation Example 6 Example 20 Preparation Example 11 Example 16 Preparation Example 7 Example 21 Preparation Example 12 Example 17 Preparation Example 8 Example 22 Preparation Example 13 Example 18 Preparation Example 9 Example 23 Preparation Example 14 Example 19 Preparation Example 10 / /

[0092] As shown in Table 8, the differences between Examples 23-27 lie in the modified fluorinated graphene proportions.

[0093] Table 8 modified fluorinated graphene ratio

[0094]

[0095]

[0096] Example 28

[0097] The difference between this example and Example 27 is that the film forming agent is a mixture of gutta-percha and modified gutta-percha, and the amount of modified gutta-percha is 20% of the total weight of the film forming agent (referred to as modified gutta-percha ratio in Table 10).

[0098] As shown in Table 9, Examples 28-32 differ in the preparation example of the modified gutta-percha.

[0099] Table 9 Preparation example of modified gutta-percha

[0100] Sample Preparation Example of modified gutta-percha Example 28 Preparation Example 15 Example 29 Preparation Example 16 Example 30 Preparation Example 17 Example 31 Preparation Example 18 Example 32 Preparation Example 19

[0101] As shown in Table 10, Examples 32-36 differ in the modified gutta-percha ratio.

[0102] Table 10 Modified gutta-percha ratio

[0103] Sample Modified gutta-percha ratio / % Example 32 20 Example 33 23 Example 34 28 Example 35 32 Example 36 35

[0104] Comparative Example

[0105] Comparative Example 1

[0106] A self-stratifying coating including the following components: hydroxyl-terminated polydimethylsiloxane 13.5 kg, hydroxyl fluorocarbon resin 22.5 kg, epoxy resin 7.2 kg, CYMEL 325 curing agent 18 kg, NACURE 2107 catalyst 0.45 kg, propylene glycol methyl ether acetate 10.35 kg, ethyl acetate 18 kg. The hydroxyl value of the hydroxyl fluorocarbon resin is 60 mgKOH / g, and the chemical formula of the hydroxyl-terminated polydimethylsiloxane is R(SiMe2O) n (CH2) m CH2OH, where n = 15, m = 6, R = -(CH2)6CH2OH. The preparation method of the self-stratifying coating is: after mixing the above components, stirring at room temperature of 25°C at a speed of 100 r / min for 60 min to obtain the self-stratifying coating.

[0107] Comparative Example 2

[0108] The difference between this comparative example and Example 1 is that the components of the self-stratifying coating do not include a toughening aid.

[0109] Comparative Example 3

[0110] The present comparative example differs from Example 1 in that the components of the self-stratifying coating do not include a film-forming aid.

[0111] Comparative Example 4

[0112] The present comparative example differs from Example 1 in that the components of the self-stratifying coating do not include a carboxyl-terminated liquid nitrile rubber.

[0113] Comparative Example 5

[0114] The present comparative example differs from Example 1 in that the fluorinated graphene has a degree of fluorination of 20%.

[0115] Performance test method

[0116] With reference to the description of GB / T 5210-2006 Color Paint and Varnish Pull-off Adhesion Test, the adhesion of the paint film of each example and comparative example was tested using 907A carbon steel as the test column material, and the test results were recorded. Taking the test results of Comparative Example 1 as the benchmark, the ratio of the adhesion of the paint film measured in each example and comparative example to the adhesion of the paint film of Comparative Example 1 was calculated, and the ratio was recorded as the relative adhesion. The results are shown in Table 11.

[0117] Table 11 Relative Adhesion

[0118]

[0119]

[0120] In combination with Examples 1-5 and Comparative Example 1 and in combination with Table 11, it can be seen that the relative adhesion measured in Examples 1-5 is higher than that of Comparative Example 1, indicating that the adhesion of the coating formed by the self-stratifying coating of the present application on the surface of 907A carbon steel is relatively high. The present application overcomes the defect that the adhesion of the coating formed by the self-stratifying coating mainly composed of E44 epoxy resin to the 907A carbon steel substrate is poor, and is conducive to the popularization and application of the self-stratifying coating.

[0121] In combination with Example 1 and Comparative Examples 2-4 and in combination with Table 11, it can be seen that when the carboxyl-terminated liquid nitrile rubber, the toughening aid represented by fluorinated graphene, and the film-forming aid represented by eucommia rubber are not used together, the adhesion of the coating formed by the self-stratifying coating on the surface of 907A carbon steel is low.

[0122] In combination with Example 1 and Comparative Example 5 and in combination with Table 11, it can be seen that when the degree of fluorination of the fluorinated graphene in the self-stratifying coating is lower than the lower limit defined in the present application, the adhesion of the coating formed by the self-stratifying coating on the surface of 907A carbon steel is low.

[0123] As can be seen from Examples 5 and 6-10 and Table 11, based on Example 5, the introduction of carboxylated epoxy resin helps to improve the adhesion between the epoxy coating and the 907A carbon steel substrate, thereby enhancing the adhesion of the coating formed by the self-layering coating.

[0124] As can be seen from Examples 10-14 and Table 11, when the amount of carboxylated epoxy resin accounts for 26-32% of the total weight of epoxy resin, the coating adhesion of the self-layering coating on the surface of 907A carbon steel is relatively high.

[0125] As can be seen from Examples 14, 15-19 and Table 11, the introduction of modified fluorinated graphene improves the adhesion of the coating formed by the self-layering paint.

[0126] Based on Examples 19-23 and Table 11, it can be seen that in step (1) of preparing modified fluorinated graphene, when the amount of fluorinated graphene is 0.1-0.2 parts by weight, the coating formed by the self-layering coating on the surface of 907A carbon steel has high adhesion.

[0127] As can be seen from Examples 23-27 and Table 11, when the amount of modified fluorinated graphene accounts for 42-50% of the total weight of the toughening additive, the coating adhesion of the self-layering coating on the surface of 907A carbon steel is relatively high.

[0128] As can be seen from Examples 27, 28-32 and Table 11, the addition of modified Eucommia ulmoides gum can further improve the adhesion of the self-layering coating on the surface of 907A carbon steel based on Example 27.

[0129] As can be seen from Examples 32-36 and Table 11, when the amount of modified Eucommia ulmoides gum accounts for 28-35% of the total weight of the film-forming aid, the coating adhesion of the self-layering coating on the surface of 907A carbon steel is relatively high.

[0130] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A weather-resistant, self-cleaning, and self-stratifying coating, characterized in that, The product comprises the following components in parts by weight: 100-105 parts propylene glycol methyl ether acetate, 180-184 parts ethyl acetate, 135-137 parts hydroxyl-terminated polydimethylsiloxane, 225-230 parts hydroxyl fluorocarbon resin, 72-74 parts epoxy resin, 5-7 parts carboxyl-terminated liquid nitrile rubber, 0.8-2.4 parts toughening agent, 2.5-4.5 parts film-forming aid, 180-184 parts curing agent, and 4.5-4.7 parts catalyst; wherein the epoxy resin includes epoxy resin E44, the toughening agent includes fluorinated graphene with a fluorination degree of 25-40%, and the film-forming aid includes eucommia gum.

2. The weather-resistant, self-cleaning, and self-stratifying coating according to claim 1, characterized in that, The epoxy resin further includes a carboxylated epoxy resin, wherein the carboxylated epoxy resin accounts for 18-32% of the total weight of the epoxy resin, and the carboxylated epoxy resin is prepared according to the following method: (1) Prepare NMP solutions of E44 epoxy resin and TDI under nitrogen protection. Then, under nitrogen protection, add the NMP solution of E44 epoxy resin to the NMP solution of TDI and stir for 120-135 min. Then, heat to 60-65℃ and continue stirring for 60-120 min to obtain TDI modified epoxy resin for later use. Dissolve tartaric acid in NMP to obtain NMP solution of tartaric acid for later use. The weight ratio of TDI, tartaric acid and E44 epoxy resin is (0.8-1.6):(0.92-1.35):

10. (2) Under nitrogen protection, TDI modified epoxy resin is added to NMP solution of tartaric acid, dibutyltin dilaurate is added, and the mixture is stirred for 120-135 min. Then the temperature is raised to 80-85℃ and the mixture is stirred for another 120-135 min. Then NMP is removed by vacuum evaporation to obtain carboxylated epoxy resin.

3. The weather-resistant, self-cleaning, and self-stratifying coating according to claim 2, characterized in that, The amount of carboxylated epoxy resin used accounts for 26-32% of the total weight of epoxy resin.

4. The weather-resistant, self-cleaning, and self-stratifying coating according to claim 1, characterized in that, The toughening agent further includes modified fluorinated graphene, wherein the amount of modified fluorinated graphene accounts for 28-50% of the total weight of the toughening agent, and the modified fluorinated graphene is prepared according to the following method: (1) Add 0.1-0.3 parts by weight of fluorinated graphene to deionized water and disperse it by ultrasonication to obtain a fluorinated graphene dispersion for later use; dissolve 1.7-2.1 parts by weight of zinc nitrate hexahydrate, 1.0-1.2 parts by weight of aluminum nitrate nonahydrate and a certain amount of urea in water to obtain a mixed solution for later use. (2) Add the mixed solution to the fluorinated graphene dispersion and stir at 95-100℃ for 10-12h to obtain modified fluorinated graphene.

5. The weather-resistant, self-cleaning, and self-stratifying coating according to claim 4, characterized in that, In step (1) of preparing the modified fluorinated graphene, the amount of fluorinated graphene used is 0.1-0.2 parts by weight.

6. The weather-resistant, self-cleaning, and self-stratifying coating according to claim 5, characterized in that, The modified fluorinated graphene accounts for 42-50% of the total weight of the toughening agent.

7. The weather-resistant, self-cleaning, and self-stratifying coating according to claim 1, characterized in that, The film-forming aid further includes modified eucommia gum, the amount of which accounts for 20-35% of the total weight of the film-forming aid, and the modified eucommia gum is prepared according to the following method: Eucommia gum was dissolved in petroleum ether by heating to obtain a Eucommia gum petroleum ether solution. Water was added to the Eucommia gum petroleum ether solution under heat preservation conditions. After 90-100 min, formic acid and hydrogen peroxide were added to the Eucommia gum petroleum ether solution. The reaction was continued for 120-130 min. The reaction product was washed with alcohol and the product was dried under vacuum to obtain modified Eucommia gum. The weight ratio of Eucommia gum, formic acid and hydrogen peroxide was 20:(6-7):(32-35).

8. The weather-resistant, self-cleaning, and self-stratifying coating according to claim 7, characterized in that, The modified Eucommia ulmoides gum accounts for 28-35% of the total weight of the film-forming aids.

9. The method for preparing the weather-resistant, self-cleaning, and self-stratifying coating according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Mix propylene glycol methyl ether acetate and ethyl acetate to obtain a solvent; mix hydroxyl-terminated polydimethylsiloxane, hydroxyl fluorocarbon resin, curing agent and epoxy resin to obtain a film-forming component; mix carboxyl-terminated liquid nitrile rubber, toughening agent, film-forming aid and catalyst to obtain an auxiliary component; (2) Add the auxiliary components to the solvent, mix and heat and stir, then add the film-forming components and continue stirring to obtain a weather-resistant, self-cleaning and self-layering coating.

10. The application of the weather-resistant, self-cleaning, and self-stratifying coating according to any one of claims 1-8, characterized in that, This includes spraying or rolling the weather-resistant, self-cleaning, and self-layering coating onto a substrate and baking and curing it at 180-245°C for 3-30 minutes.

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