Water-based protective coating composition for engine, preparation method of water-based protective coating composition, water-based protective coating containing water-based protective coating composition and application

Abstract

The invention discloses a water-based protective coating composition for an engine as well as a preparation method and application of the water-based protective coating composition. The water-based protective coating composition for the engine comprises the following components in parts by weight: 55-60 parts of water-based epoxy resin; 1.5 to 2.5 parts of coloring pigment; 9-12 parts of an anticorrosive filler; 1.5 to 3.0 parts of a rheological additive; 7-12 parts of a film forming solvent; and 10 to 20 parts of deionized water. The water-based protective coating composition has good salt fog resistance and water resistance, meanwhile, compared with a conventional water-based coating, the water-based protective coating composition has excellent performance, has the characteristics of high film thickness, no hanging, no prickly heat, high drying speed, plump appearance, high gloss and the like, and can be used for coating engine assemblies of heavy trucks, ships and engineering machinery.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and more specifically, to an engine water-based protective coating composition, a preparation method thereof, a water-based protective coating containing the same, and applications thereof. Background Art

[0002] The water-based protective coating composition is a two-component product. Component A is composed of water-based epoxy resin, and component B is a fatty amine water-based curing agent. The water-based epoxy resin and the fatty amine water-based curing agent are the main film-forming substances. The epoxy resin and the fatty amine film have strong cohesive force, the material structure is dense, the coating has good ductility and contains highly active epoxy groups, hydroxyl groups, ether bonds, ester bonds and other polar groups, which give the epoxy resin coating excellent adhesion to polar substrates such as metals, plastics, nylon, etc., and at the same time have good corrosion resistance on metal substrates.

[0003] With the improvement of environmental protection requirements, environmental protection laws and regulations are becoming more and more stringent. Various environmental protection regulations have strict restrictions on the emission of volatile organic compounds (VOC), harmful solvents and the content of various heavy metals. Therefore, the development of green, environmentally friendly, low-VOC emission water-based coatings has become a trend in the coatings industry. Summary of the invention

[0004] Based on the above facts, the purpose of the present invention is to provide an engine water-based protective coating composition, a preparation method thereof, a water-based protective coating containing the same, and applications. The water-based protective coating composition has good salt spray resistance and water resistance, and compared with conventional water-based coatings, has excellent performance, which is manifested in high film thickness without hanging, without prickly heat, fast drying, and a plump and high gloss appearance. It can be used for coating engine assemblies of heavy trucks, ships, and engineering machinery.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A water-based protective coating composition for an engine, comprising the following components by weight percentage:

[0007]

[0008] Furthermore, the non-volatile content of the waterborne epoxy resin is 43.0-54%.

[0009] Furthermore, the viscosity of the waterborne epoxy resin is 100-6000 mPa.s / 25°C.

[0010] Furthermore, the epoxy equivalent of the waterborne epoxy resin is 900 to 1200 g / Eq.

[0011] Furthermore, the coloring pigment is carbon black.

[0012] Furthermore, the particle size of the anticorrosive filler is 800-1500 meshes.

[0013] Furthermore, the oil absorption of the anticorrosive filler is 10 to 50 g / 100 g.

[0014] Furthermore, the antiseptic filler is selected from barium sulfate.

[0015] Furthermore, the rheological additive is a polyurethane rheological additive, and its mass solid content is 19-42%.

[0016] Furthermore, the membrane-forming solvent is selected from one or more of ethylene glycol monobutyl ether, ethylene glycol hexyl ether and dipropylene glycol butyl ether.

[0017] Furthermore, it also contains one or more auxiliary agents selected from the group consisting of a leveling agent, a defoaming agent, a substrate wetting agent and a wetting and dispersing agent.

[0018] Furthermore, the dosage of the auxiliary agent is 3 to 5 parts.

[0019] Furthermore, the auxiliary agent comprises, by weight percentage:

[0020] 1.6 to 2.8 parts of wetting and dispersing agent, preferably 1.6 to 2.4 parts, more preferably 2.4 to 2.8 parts;

[0021] 0.2 to 0.5 parts of defoaming agent, preferably 0.2 to 0.4 parts, more preferably 0.4 to 0.5 parts;

[0022] 0.2 to 0.6 parts of substrate wetting agent, preferably 0.20 to 0.4 parts, more preferably 0.4 to 0.6 parts;

[0023] The amount of the leveling agent is 0.2 to 0.4 parts, preferably 0.20 to 0.3 parts, and more preferably 0.3 to 0.4 parts.

[0024] In another aspect, the present invention provides a method for preparing the aqueous protective coating composition as described above, comprising the steps of:

[0025] (1) Put the wetting dispersant, defoamer, part of deionized water and part of the film-forming solvent into container A, stir at 600-900 r / min, add coloring pigment and anticorrosive filler under stirring, stir for 20-30 min, stop stirring after the mixture is evenly dispersed without lumps, and set aside;

[0026] (2) Grind the mixed material in container A to a fineness of ≤10 μm for later use;

[0027] (3) Add the remaining deionized water in the formula into container B, stir at 300-400 r / min, add water-based epoxy resin, stir for 5-10 minutes, then add the mixture in container A, the remaining film-forming solvent, substrate wetting agent, and leveling agent in the formula amount in sequence, and continue stirring for 10-15 minutes;

[0028] (4) adjusting the viscosity with a rheological additive and stirring for 20 to 30 minutes to obtain the waterborne epoxy protective coating composition.

[0029] In another aspect, the present invention provides a water-based protective coating, comprising a resin part and a curing agent part; wherein the resin part is composed of the water-based protective coating composition as described above.

[0030] In another aspect, the present invention provides the use of the aforementioned water-based protective coating composition or water-based protective coating in the coating of engine assemblies of heavy trucks, ships, and engineering machinery.

[0031] The beneficial effects of the present invention are as follows:

[0032] The water-based protective coating composition provided by the present invention uses water-based epoxy resin as the main resin, and is matched with coloring pigments, anticorrosive fillers, rheological additives, film-forming solvents, and other additives. The resin part composed of the above composition is combined with a curing agent part (for example, a water-based fatty amine curing agent) to be used in a two-component water-based protective coating. The prepared water-based protective coating is sprayed on the engine assembly of heavy trucks, ships, and engineering machinery. The pencil hardness of the paint film after curing can reach H, the neutral salt spray coating with a film thickness of 30 microns is rust-free for 500 hours, and it is water-resistant at 40°C for 240 hours without blistering or peeling. The appearance is plump and the gloss (60°) can reach more than 95, and it has good salt spray resistance, water resistance and excellent appearance. DETAILED DESCRIPTION

[0033] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0034] According to a specific embodiment of the present invention, there is provided a water-based protective coating composition for an engine, characterized in that it comprises the following components in parts by weight:

[0035]

[0036] The water-based protective coating composition provided by the present invention uses water-based epoxy resin as the main resin, and is equipped with an appropriate amount of coloring pigments and anticorrosive fillers. The water-based protective coating composition is combined with a water-based fatty amine curing agent to solve the problem of rapid surface drying and film-forming non-stick spraying equipment of a two-component water-based protective coating composition. Furthermore, the water-based protective coating composition is equipped with an appropriate amount of rheological additives and other additives to give it good construction properties and a good paint film appearance. The obtained paint film coating has good ductility and contains relatively active epoxy groups, hydroxyl groups, ether bonds, ester bonds and other polar groups, giving the epoxy resin coating excellent adhesion to polar substrates such as metals, plastics, and nylons, and at the same time having good corrosion resistance on metal substrates. At the same time, it is ensured that the other properties of the water-based protective coating composition remain unchanged. The water-based protective coating composition can be simply sprayed with air, is simple to construct, easy to operate, has a fast surface drying rate, and is used for the coating of engine assemblies of heavy trucks, ships, and engineering machinery.

[0037] In some examples, the non-volatile content of the waterborne epoxy resin is 43.0-54%, the viscosity is 100-6000 mPa.s / 25°C, and the epoxy equivalent is 900-1200 g / Eq. The selection of the waterborne epoxy resin can give the coating good positive impact, neutral salt spray, high temperature resistance, gloss, DOI, solvent resistance and other properties. Exemplary waterborne epoxy resins include, but are not limited to, EP-387W (purchased from Allnex Resins Co., Ltd.) and the like.

[0038] Exemplarily, the amount of the waterborne epoxy resin includes but is not limited to 55-57 parts, 57-60 parts, 55 parts, 57 parts, 60 parts, etc. At this time, the obtained coating composition is used in waterborne coatings to have better paint film pencil hardness, salt spray resistance, water resistance, moisture resistance, solvent resistance and good appearance.

[0039] In some examples, the coloring pigment is carbon black. Exemplary coloring pigments include, but are not limited to, MITSUBISHI CARBON BLACK MA-100 carbon black (available from Mitsubishi Chemical) and the like.

[0040] Exemplarily, the amount of the coloring pigment includes but is not limited to 1.5-2 parts, 2-2.5 parts, 1.5 parts, 2 parts, 2.5 parts, etc. At this time, the obtained coating composition is used in water-based coatings and has good hiding power, impact, strength and appearance.

[0041] In some examples, the anticorrosive filler is selected from barium sulfate. The anticorrosive filler can further improve the salt spray resistance of the coating without affecting the appearance of the coating (such as gloss, DOI performance, etc.), which is mainly reflected in reducing the expansion corrosion of the X-shaped tangent part of the metal parts during the salt spray resistance test. This is because its fine particles fill the coating structure, play a shielding role, reduce the permeability of the coating, and thus play an anti-rust role. In addition, through experimental comparison in the present invention, it is found that selecting barium sulfate as an anticorrosive filler can achieve a better appearance gloss than other fillers such as talcum powder as an anticorrosive filler.

[0042] In some examples, the particle size of the anticorrosive filler is 800-1500 mesh. By controlling the particle size of the anticorrosive filler, the coating can be given better impact resistance, gloss and salt spray resistance. Exemplary particle sizes of anticorrosive fillers include but are not limited to 900-1400 mesh, 1000-1300 mesh, 1250 mesh, etc.

[0043] In some examples, the oil absorption of the anticorrosive filler is 10 to 50 g / 100 g.

[0044] In some specific examples of this embodiment, the amount of anticorrosive filler added includes but is not limited to 9-10 parts, 10-12 parts, 9 parts, 10 parts, 12 parts, etc. By controlling the amount of anticorrosive filler, the coating can be prevented from being too brittle, having reduced adhesion to the substrate, or having insufficient hardness and poor solvent resistance.

[0045] In some examples, the rheological additive is a polyurethane rheological additive with a mass solid content of 19 to 42%. The rheological additive is used in this embodiment to increase the thixotropy of the coating, so as to improve the paintability of the coating at the chamfered position of the edge of the metal workpiece, increase the thickness of the paint film at this position, and thus achieve the purpose of improving the corrosion resistance of this position.

[0046] In some examples, the rheological additive includes rheological additive A and rheological additive B; wherein rheological additive A is RM-8W (purchased from Dow), which is a polyurethane type, and its solid content is 19-22%; the rheological additive B is MST-299 (purchased from Haimings Special Chemical Company), which is a polyurethane type, and its solid content is 38-42%. By mixing these two rheological additives, the paintability of the coating at the chamfered position of the edge of the metal workpiece can be better improved, and the thickness of the paint film at this position can be increased, thereby achieving the improvement of the corrosion resistance of this position. The mass ratio of rheological additive A to rheological additive B includes but is not limited to 1.3:0.8.

[0047] Furthermore, the film-forming solvent is selected from ether solvents, water, or a combination thereof, which can solve the problem of prickly heat on the surface of the paint film after the paint film is heated and dried during the film-forming process.

[0048] The ether solvent has a lower evaporation rate than deionized water and has good compatibility with deionized water, which can adjust the evaporation rate of the entire coating system and avoid abnormalities such as blistering / prickly heat / blooming during coating and baking. In some examples, the film-forming solvent is selected from one or more of ethylene glycol monobutyl ether, ethylene glycol hexyl ether and dipropylene glycol butyl ether.

[0049] In some examples, the water-based protective coating composition further comprises one or more additives selected from the group consisting of a leveling agent, a defoamer, a substrate wetting agent, and a wetting and dispersing agent. In the composition, the amount of the additive is preferably 3 to 5 parts.

[0050] In some examples, the auxiliary agent includes, by weight:

[0051] 1.6 to 2.8 parts of a wetting and dispersing agent, preferably 1.6 to 2.4 parts, more preferably 2.4 to 2.8 parts; optional wetting and dispersing agents include but are not limited to BYK 190 (available from BYK);

[0052] 0.2-0.5 parts of defoaming agent, preferably 0.2-0.4 parts, more preferably 0.4-0.5 parts; optional defoaming agent includes but is not limited to BYK 011 (purchased from BYK Company);

[0053] 0.2-0.6 parts of substrate wetting agent, preferably 0.20-0.4 parts, more preferably 0.4-0.6 parts; optional substrate wetting agent includes but is not limited to TEGO 4100 (purchased from TEGO Company);

[0054] The leveling agent is 0.2-0.4 parts, preferably 0.20-0.3 parts, and more preferably 0.3-0.4 parts; the optional leveling agent includes but is not limited to BYK 381 (purchased from BYK Company).

[0055] In some examples, the weight of each component is based on 100 parts by weight of the total waterborne protective coating composition.

[0056] According to another specific embodiment of the present invention, there is provided a method for preparing the above-mentioned water-based protective coating composition, comprising the steps of:

[0057] (1) Put the wetting dispersant, defoamer, part of deionized water and part of the film-forming solvent into container A, stir at 600-900 r / min, add coloring pigment and anticorrosive filler under stirring, stir for 20-30 min, stop stirring after the mixture is evenly dispersed without lumps, and set aside;

[0058] (2) Grind the mixed material in container A to a fineness of ≤10 μm for later use;

[0059] (3) Add the remaining deionized water in the formula into container B, stir at 300-400 r / min, add water-based epoxy resin, stir for 5-10 minutes, then add the mixture in container A, the remaining film-forming solvent, substrate wetting agent, and leveling agent in the formula amount in sequence, and continue stirring for 10-15 minutes;

[0060] (4) adjusting the viscosity with a rheological additive and stirring for 20 to 30 minutes to obtain the waterborne epoxy protective coating composition.

[0061] According to another specific embodiment of the present invention, there is provided a water-based protective coating, which comprises a resin part and a curing agent part; wherein the resin part is composed of the water-based protective coating composition as described above.

[0062] In some examples, the curing agent portion is a water-based fatty amine curing agent.

[0063] In some specific examples, the mass ratio of the resin part to the curing agent part is 100:25.

[0064] According to another specific embodiment of the present invention, there is provided the use of the aforementioned water-based protective coating composition or the aforementioned water-based protective coating in the coating of engine assemblies of heavy trucks, ships, and engineering machinery.

[0065] The technical solution of the present invention is described below in conjunction with some specific embodiments:

[0066] raw material

[0067] The waterborne epoxy resin was EP-387W (purchased from Allnex Resins Co., Ltd.);

[0068] The coloring pigment was MITSUBISHI CARBON BLACK MA-100 carbon black, purchased from Mitsubishi Chemical;

[0069] The anticorrosive filler was barium sulfate, purchased from Hebei Xinji Chemical Industry;

[0070] The rheological additive A is RM-8W (purchased from Dow Chemical Company);

[0071] The rheological additive B is MST-299 (purchased from Haimingsi Specialty Chemical Company);

[0072] Wetting and dispersing agent BYK 190, purchased from BYK;

[0073] The defoamer was BYK 011, purchased from BYK;

[0074] The substrate wetting agent was TEGO 4100, purchased from TEGO Company;

[0075] The leveling agent was BYK 381, purchased from BYK;

[0076] Water-based fatty amine curing agent is EPIKURE TM 6870-W-53, purchased from Westlake Corporation.

[0077] Example 1: Water-based protective coating composition 1

[0078] A water-based protective coating composition 1 was prepared according to the formulation shown in Table 1 below.

[0079] Table 1 Weight parts of raw materials in Example 1

[0080]

[0081] The preparation process of the water-based protective coating composition 1 comprises the following steps:

[0082] (1) 2.0 parts of wetting and dispersing agent (BYK-190), 0.5 parts of defoaming agent (BYK-011), 13.7 parts of deionized water and 4.0 parts of ethylene glycol monobutyl ether were added into container A and stirred at 600 r / min. 2.0 parts of carbon black and 10 parts of barium sulfate were added into the container under stirring and stirred for about 20 to 30 minutes. After the mixture was dispersed evenly without lumps, stirring was stopped and the mixture was set aside.

[0083] (2) Grind the mixed material in container A to a fineness of ≤10.0 μm and set aside;

[0084] (3) Add the remaining 3.0 parts of water into container B, stir at 600 r / min, add 57 parts of waterborne epoxy resin EP-387W, and then add the pigment and filler slurry mixture in container A, 2.0 parts of ethylene glycol hexyl ether, 3.0 parts of dipropylene glycol butyl ether, 0.4 parts of substrate wetting agent TEGO 4100, 0.3 parts of leveling agent BYK 381 and other materials in the formula amount, and continue stirring for 15 minutes;

[0085] (4) Continue stirring in container B at 600 r / min, add 1.3 parts of rheological additive A (RM-8W) and 0.8 parts of rheological additive B (MST-299), stir for 20 to 30 minutes, adjust to a suitable viscosity, and obtain the water-based protective coating composition.

[0086] Comparative Example 1: Water-based protective coating composition C1

[0087] Example 1 was repeated, except that the waterborne epoxy resin in Example 1 was replaced by a commercially available waterborne epoxy resin 3EE104W in equal solid amounts, and the amounts of other materials remained unchanged.

[0088] Comparative Example 2: Water-based protective coating composition C2

[0089] Example 1 was repeated, except that the solid amount of commercially available water-based epoxy resin LWEA-3250NP was used to replace the water-based epoxy resin in Example 1, and the amounts of other materials remained unchanged.

[0090] Comparative Example 3: Water-based protective coating composition C3

[0091] Example 1 was repeated, except that the solid amount of commercially available water-based epoxy resin WEP-10 or the like was used to replace the water-based epoxy resin in Example 1, and the amounts of other materials remained unchanged.

[0092] Comparative Example 4: Water-based protective coating composition C4

[0093] Example 1 was repeated, the only difference being the amount of EP-387W used. The weight percentages of the raw materials in Comparative Example 4 are shown in Table 2.

[0094] Table 2 Comparative Example 4 Raw Materials by Weight

[0095]

[0096] Example 2: Water-based protective coating composition 2

[0097] Example 1 was repeated, the only difference being the amount of EP-387W used. The weight portions of the raw materials in Example 2 are shown in Table 3.

[0098] Table 3 Weight parts of raw materials in Example 2

[0099]

[0100] Example 3: Water-based protective coating composition 3

[0101] Example 1 was repeated, the only difference being the amount of EP-387W used. The weight portions of the raw materials in Example 3 are shown in Table 4.

[0102] Table 4 Weight parts of raw materials in Example 3

[0103]

[0104] Comparative Example 5: Water-based protective coating composition C5

[0105] Example 1 was repeated, the only difference being the amount of EP-387W used. The weight percentages of the raw materials in Comparative Example 5 are shown in Table 5.

[0106] Table 5 Comparative Example 5 Raw Materials by Weight

[0107]

[0108]

[0109] Comparative Example 6: Water-based protective coating composition C6

[0110] Example 1 was repeated, except that the anticorrosive filler (1250 mesh barium sulfate) in Example 1 was replaced by an equal amount of commercially available 1500 mesh barium sulfate, and the other contents remained unchanged.

[0111] Comparative Example 7: Water-based protective coating composition C7

[0112] Example 1 was repeated, except that the anticorrosive filler (1250 mesh barium sulfate) in Example 1 was replaced by an equal amount of commercially available 800 mesh barium sulfate, and the other contents remained unchanged.

[0113] Comparative Example 8: Water-based protective coating composition C8

[0114] Example 1 was repeated, except that the antiseptic filler (1250 mesh barium sulfate) in Example 1 was replaced by an equal amount of commercially available 1250 mesh talc powder, and the other contents remained unchanged.

[0115] Example 4: Water-based protective coating composition 4

[0116] Example 1 was repeated, the only difference being the amount of 1250 mesh barium sulfate used, the weight parts of the raw materials in Example 4 were as shown in Table 6, and the amount of the anticorrosive filler was different.

[0117] Table 6 Example 4 Raw materials weight parts

[0118]

[0119]

[0120] Example 5: Water-based protective coating composition 5

[0121] Example 1 was repeated, the only difference being the amount of 1250 mesh barium sulfate used. The weight percentages of the raw materials in Example 5 were as shown in the table, and the amount of the antiseptic filler was different.

[0122] Table 7 Weight parts of raw materials in Example 5

[0123]

[0124] Comparative Example 9: Water-based protective coating composition C9

[0125] Example 1 was repeated, the only difference being the amount of 1250 mesh barium sulfate used. The weight percentages of the raw materials in Comparative Example 9 were as shown in the table, and the amount of the antiseptic filler was different.

[0126] Table 8 Comparative Example 9 Raw Materials by Weight

[0127]

[0128] Comparative Example 10: Water-based protective coating composition C10

[0129] Example 1 was repeated, the only difference being the amount of 1250 mesh barium sulfate used. The weight percentages of the raw materials in Comparative Example 10 are shown in Table 9, and the amount of the anticorrosive filler was different.

[0130] Table 9 Comparative Example 10 Raw Materials by Weight

[0131]

[0132] Example 6: Water-based protective coating composition 6

[0133] Example 1 was repeated, except that the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was used. The weight percentages of the raw materials in Example 6 are shown in Table 10, and the amount of coloring pigment used was different.

[0134] Table 10 Weight parts of raw materials in Example 6

[0135]

[0136] Example 7: Water-based protective coating composition 7

[0137] Example 1 was repeated, except that the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was used, the weight parts of the raw materials in Example 7 were as shown in Table 11, and the amount of coloring pigment was different.

[0138] Table 11 Raw materials weight parts of Example 7

[0139]

[0140]

[0141] Comparative Example 11: Water-based protective coating composition C11

[0142] Example 1 was repeated, except that the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was used. The weight percentages of the raw materials in Comparative Example 11 are shown in Table 12, and the amount of coloring pigment used was different.

[0143] Table 12 Comparative Example 11 Raw Materials by Weight

[0144]

[0145] Comparative Example 12: Water-based protective coating composition C12

[0146] Example 1 was repeated, except that the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was used. The weight percentages of the raw materials in Comparative Example 12 are shown in Table 13, and the amount of coloring pigment used was different.

[0147] Table 13 Comparative Example 12 Raw Materials by Weight

[0148]

[0149]

[0150] Test Example 1: Performance test of water-based protective coating

[0151] Water-based protective coating: The water-based protective coating composition of each embodiment and comparative example is mixed with a water-based fatty amine curing agent EPIKURE TM 6870-W-53 is mixed in a mass ratio of 100:25.

[0152] Substrate: Cold rolled steel plate and cold rolled aluminum plate (polished with 400 grit sandpaper).

[0153] Coating process: air gun spraying, spraying viscosity 35.0-38.0″ / 20℃*apply 4 cups.

[0154] Coating composition: polished cold rolled plate + water-based protective coating.

[0155] The engine workpiece coating is baked at 60°C*30min (effective temperature of the workpiece surface) and then naturally cured for 10 days at room temperature to obtain a water-based protective coating for heavy-duty vehicle engines.

[0156] Due to the different production line process conditions of different automobile metal parts production plants, the baking conditions of some automobile metal parts production plants are 80℃*30min (effective temperature of the workpiece surface). The inventors found that under this baking condition, the natural curing time of the workpiece at room temperature can be shortened to 7 days.

[0157] The test methods for each property are shown in Table 14.

[0158] Table 14 Performance test methods

[0159]

[0160] The above method was used to test the performance of the water-based protective coatings of each embodiment and comparative example. The results are shown in Tables 15 to 18.

[0161] Table 15 Performance of water-based protective coatings of Examples 1-2 and Comparative Examples 1-4

[0162]

[0163]

[0164] Table 16 Performance of water-based protective coatings for Examples 3-4 and Comparative Examples 5-8

[0165]

[0166]

[0167] Table 17 Performance of water-based protective coatings of Examples 5-7 and Comparative Examples 9-11

[0168]

[0169]

[0170] Table 18 Performance of water-based protective coating of Comparative Example 12

[0171] Test items Comparative Example 12 Coating appearance No abnormality Covering power 9 microns Positive impact (national standard) 30KG*CM(Unqualified) Pencil hardness H luster 20°=88 60°=93(Unqualified) DOI value 83 (Unqualified) Adhesion 100-grid method, 100 / 100 no peeling Water resistance No change Moisture resistance No change Solvent resistance No change Neutral salt spray The average rust width on one side is 1.85mm, and there is no rust in other places High temperature resistance Gloss retention rate (60°) 75%, color difference ΔE = 0.25 Test Conclusion Failure

[0172] It can be seen from Table 15 that the water-based protective coating prepared in Example 1 is sprayed under standard construction conditions, and the paint film has no abnormal appearance, and the coating film performance meets the technical index requirements.

[0173] As can be seen from Table 15, Comparative Example 1 uses commercially available water-based epoxy resin 3EE104W to replace the water-based epoxy resin in Example 1 in solid amount, and the amount of other materials remains unchanged. The positive impact, neutral salt spray, and high temperature resistance tests are all unqualified. This is because the commercially available resin itself has poor adhesion to the metal substrate.

[0174] As can be seen from Table 15, in Comparative Example 2, the solid amount of the commercially available water-based epoxy resin LWEA-3250NP was used to replace the water-based epoxy resin in Example 1, and the amount of other materials remained unchanged. The positive impact, gloss, DOI, and solvent resistance tests were all unqualified. This is due to the poor gloss, fullness, flexibility, and cross-linking strength of the commercially available resin itself.

[0175] As can be seen from Table 15, in Comparative Example 3, the water-based epoxy resin in Example 1 is replaced by the commercially available water-based epoxy resin WEP-10 in solid amount, and the amount of other materials remains unchanged. The neutral salt spray test fails, which is due to the poor anti-corrosion performance of the commercially available resin itself.

[0176] As can be seen from Table 15, in Comparative Example 4, the amount of water-based resin added in Example 1 was changed to 54%, and the amounts of other materials remained unchanged, but the gloss test failed. This was due to the fact that the amount of resin used was too small and the pigment-to-base ratio was too high.

[0177] It can be seen from Table 15 that in Example 2, the amount of water-based resin added in Example 1 is changed to 55%, and other materials remain unchanged. The test performance is qualified, which is the lower limit of the resin usage.

[0178] It can be seen from Table 16 that in Example 3, the amount of water-based resin added in Example 1 is changed to 60%, other materials remain unchanged, and the test performance is qualified, which is the upper limit of the resin usage.

[0179] As can be seen from Table 16, in Comparative Example 5, the amount of water-based resin added in Example 1 was changed to 61%, and other materials remained unchanged. The hiding power and neutral salt spray tests failed. This was due to the excessive amount of resin used and the low pigment-to-base ratio.

[0180] As can be seen from Table 16, in Comparative Example 6, the 1250-mesh barium sulfate was replaced with the 1500-mesh barium sulfate, and other materials remained unchanged, but the positive impact test failed. This is because the oil absorption of the 1500-mesh barium sulfate was too high and the flexibility of the system was insufficient.

[0181] As can be seen from Table 16, in Comparative Example 7, 1250-mesh barium sulfate was replaced with 800-mesh barium sulfate, and other materials remained unchanged. The gloss and neutral salt spray tests failed because the barium sulfate particle size was too large, affecting the salt spray and gloss.

[0182] As can be seen from Table 16, in Comparative Example 8, 1250-mesh barium sulfate was replaced with 1250-mesh talc, and other materials remained unchanged. The gloss, DOI, neutral salt spray and high temperature resistance tests failed. This is because the talc absorbed too much oil and the main component of talc, magnesium silicate, was not resistant to high temperatures.

[0183] As can be seen from Table 16, in Example 4, the amount of 1250-mesh barium sulfate used was changed to 9%, and other materials remained unchanged. The performance tests were all qualified, which is the lower limit of 1250-mesh barium sulfate.

[0184] As can be seen from Table 17, in Example 5, the amount of 1250-mesh barium sulfate used was changed to 12%, and other materials remained unchanged. The performance tests were all qualified, which is the upper limit of 1250-mesh barium sulfate.

[0185] As can be seen from Table 17, in Comparative Example 9, the amount of 1250-mesh barium sulfate was changed to 13%, and other materials remained unchanged. The positive impact, gloss, DOI, neutral salt spray and high temperature resistance tests failed. This was because the excessive amount of barium sulfate used and the high pigment-to-base ratio caused the paint film to become brittle and the adhesion between the coating and the substrate to decrease.

[0186] As can be seen from Table 17, in Comparative Example 10, the amount of 1250-mesh barium sulfate was changed to 8%, and other materials remained unchanged. The hardness and solvent resistance tests failed. This was because the amount of barium sulfate used was too small, the pigment-to-base ratio was too low, resulting in a softened paint film and insufficient reduction in coating strength.

[0187] As can be seen from Table 17, in Example 6, the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was changed to 1.5%, and other materials remained unchanged. The performance tests were all qualified, which is the lower limit of the amount of carbon black used.

[0188] As can be seen from Table 17, in Example 7, the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was changed to 2.5%, and other materials remained unchanged. The performance tests were all qualified, which is the upper limit of the amount of carbon black used.

[0189] As can be seen from Table 17, in Comparative Example 11, the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was changed to 1.4%, and other materials remained unchanged. The hiding power of the performance test was unqualified. This was because the amount of coloring pigment carbon black used was too small, resulting in insufficient hiding power of the coating.

[0190] As can be seen from Table 18, in Comparative Example 12, the amount of MITSUBISHI CARBON BLACK MA-100 carbon black was changed to 2.6%, and other materials remained unchanged. The positive impact, gloss, and DOI performance tests failed. This is because the amount of coloring pigment carbon black used was too much, and the high oil absorption of carbon black made the system brittle and the appearance deteriorated, resulting in failure in the performance test.

[0191] Comparative Example 13: Water-based protective coating composition C13

[0192] Example 1 was repeated, and the only difference of Comparative Example 13 was that during the preparation of the water-based protective coating C13, the fineness of the grinding slurry was controlled at 12.5 μm:

[0193] (1) 2.0 parts of wetting and dispersing agent (BYK-190), 0.5 parts of defoaming agent (BYK-011), 13.7 parts of deionized water and 4.0 parts of ethylene glycol monobutyl ether were added into container A and stirred at 600 r / min. 2.0 parts of carbon black and 10 parts of barium sulfate were added into the container under stirring and stirred for about 20 to 30 minutes. After the mixture was dispersed evenly without lumps, stirring was stopped and the mixture was set aside.

[0194] (2) Grind the mixed material in container A to a fineness of ≤12.5 μm and set aside;

[0195] (3) Add the remaining 3.0 parts of water into container B, stir at 600 r / min, add 57 parts of waterborne epoxy resin EP-387W, and then add the pigment and filler slurry mixture in container A, 2.0 parts of ethylene glycol hexyl ether, 3.0 parts of dipropylene glycol butyl ether, 0.4 parts of substrate wetting agent TEGO 4100, 0.3 parts of leveling agent BYK 381 and other materials in the formula amount, and continue stirring for 15 minutes;

[0196] (4) Continue stirring in container B at 600 r / min, add 1.3 parts of rheological additive A (RM-8W) and 0.8 parts of rheological additive B (MST-299), stir for 20 to 30 minutes, adjust to a suitable viscosity, and obtain the water-based protective coating composition.

[0197] The water-based protective coating composition is mixed with a water-based fatty amine curing agent EPIKURE TM 6870-W-53 is mixed in a mass ratio of 100:25 to obtain a water-based protective coating.

[0198] The salt spray resistance of the prepared water-based protective coating deteriorated, the average rust width on one side was 2.5 mm, and other positions were rusted, indicating that the fineness control of the grinding slurry in the preparation method of the present invention can effectively improve the salt spray resistance of the coating.

[0199] Comparative Example 14: Water-based protective coating composition C14

[0200] The difference between Comparative Example 14 and Example 1 is that during the preparation of the water-based protective coating C14, part of the water-based epoxy resin, dispersant, pigment and filler are ground and dispersed together:

[0201] (1) 17 parts of waterborne epoxy resin EP-387W, 2.0 parts of wetting and dispersing agent (BYK-190), 0.5 parts of defoaming agent (BYK-011), 13.7 parts of deionized water, and 4.0 parts of ethylene glycol monobutyl ether were added into container A and stirred at 600 r / min. 2.0 parts of carbon black and 10 parts of barium sulfate were added under stirring and stirred for about 20 to 30 minutes. Stirring was stopped after the mixture was evenly dispersed without lumps and set aside;

[0202] (2) Grind the mixed material in container A to a fineness of ≤10.0 μm and set aside;

[0203] (3) Add the remaining 3.0 parts of water into container B, stir at 600 r / min, add 40 parts of waterborne epoxy resin EP-387W, and then add the pigment and filler slurry mixture in container A, 2.0 parts of ethylene glycol hexyl ether, 3.0 parts of dipropylene glycol butyl ether, 0.4 parts of substrate wetting agent TEGO 4100, 0.3 parts of leveling agent BYK 381 and other materials in the formula amount, and continue stirring for 15 minutes;

[0204] (4) Continue stirring in container B at 600 r / min, add 1.3 parts of rheological additive A (RM-8W) and 0.8 parts of rheological additive B (MST-299), stir for 20 to 30 minutes, adjust to a suitable viscosity, and obtain the water-based protective coating composition.

[0205] The water-based protective coating composition is mixed with a water-based fatty amine curing agent EPIKURE TM 6870-W-53 is mixed in a mass ratio of 100:25 to obtain a water-based protective coating.

[0206] The prepared water-based protective coating has flocculation and roughening phenomena, which indicates that the steps of the preparation method of the present invention can effectively prevent agglomeration.

[0207] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A water-based protective coating composition for an engine, It is characterized in that By weight, it contains the following components:

2. The water-based protective coating composition according to claim 1, It is characterized in that The non-volatile content of the waterborne epoxy resin is 43.0-54%; and / or The viscosity of the waterborne epoxy resin is 100-6000 mPa.s / 25°C; and / or The epoxy equivalent of the waterborne epoxy resin is 900 to 1200 g / Eq.

3. The water-based protective coating composition according to claim 1, It is characterized in that The coloring pigment is carbon black.

4. The water-based protective coating composition according to claim 1, It is characterized in that The particle size of the anticorrosive filler is 800 to 1500 mesh; and / or The oil absorption of the anticorrosive filler is 10 to 50 g / 100 g; and / or The anti-corrosion filler is selected from barium sulfate.

5. The water-based protective coating composition according to claim 1, It is characterized in that The rheological additive is a polyurethane rheological additive, and its mass solid content is 19-42%.

6. The water-based protective coating composition according to claim 1, It is characterized in that The film-forming solvent is selected from one or more of ethylene glycol monobutyl ether, ethylene glycol hexyl ether and dipropylene glycol butyl ether.

7. The water-based protective coating composition according to claim 1, It is characterized in that It also contains one or more additives selected from the group consisting of a leveling agent, a defoaming agent, a substrate wetting agent, and a wetting and dispersing agent; Preferably, the amount of the auxiliary agent is 3 to 5 parts; and / or Preferably, the auxiliary agent comprises, by weight: 1.6 to 2.8 parts of wetting and dispersing agent, preferably 1.6 to 2.4 parts, more preferably 2.4 to 2.8 parts; 0.2 to 0.5 parts of defoaming agent, preferably 0.2 to 0.4 parts, more preferably 0.4 to 0.5 parts; 0.2 to 0.6 parts of substrate wetting agent, preferably 0.20 to 0.4 parts, more preferably 0.4 to 0.6 parts; The amount of the leveling agent is 0.2 to 0.4 parts, preferably 0.20 to 0.3 parts, and more preferably 0.3 to 0.4 parts.

8. A method for preparing the water-based protective coating composition according to any one of claims 1 to 7, It is characterized in that Includes steps: (1) Put the wetting dispersant, defoamer, part of deionized water and part of the film-forming solvent into container A, stir at 600-900 r / min, add coloring pigment and anticorrosive filler under stirring, stir for 20-30 min, stop stirring after the mixture is evenly dispersed without lumps, and set aside; (2) Grinding the mixed material in container A to a fineness of ≤10 μm for later use; (3) Add the remaining deionized water in the formula into container B, stir at 300-400 r / min, add water-based epoxy resin, stir for 5-10 minutes, then add the mixture in container A, the remaining film-forming solvent, substrate wetting agent, and leveling agent in the formula amount in sequence, and continue stirring for 10-15 minutes; (4) adjusting the viscosity with a rheological additive and stirring for 20 to 30 minutes to obtain the waterborne epoxy protective coating composition.

9. A water-based protective coating, It is characterized in that It comprises a resin part and a curing agent part; wherein the resin part is composed of the water-based protective coating composition according to any one of claims 1 to 7.

10. Use of the water-based protective coating composition according to any one of claims 1 to 7 or the water-based protective coating according to claim 9 in coating engine assemblies of heavy trucks, ships, and engineering machinery.

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