A water-based baking paint for non-passivated aluminum alloy shock absorbers, a preparation method thereof and applications thereof

Abstract

The application discloses a water-based baking paint for a non-passivated aluminum alloy shock absorber, which is prepared from raw materials including the following weight percentages: 35-75% of a water-based polyester resin with a triblock structure, 5-10% of a tertiary amine compound, 5-15% of an amino resin, 0.2-0.5% of a leveling agent, 0.2-0.5% of a defoaming agent, 5-30% of a pigment paste, 1-15% of a film-forming aid, and 10-40% of water. The water-based baking paint has the advantages of good water resistance, good wet heat resistance, good impact resistance, good disc construction adaptability, good re-coating performance, good storage stability, safety and environmental protection, and is suitable for large-scale industrialized disc electrostatic spraying on the non-passivated aluminum alloy, can not only solve the problem that existing water-based baking paints are prone to oxygen and water permeation after curing, thus having poor corrosion resistance, but also can provide more durable protection performance in the face of long-term impact on the shock absorber.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a water-based baking paint for non-passivated aluminum alloy shock absorbers, its preparation method, and its application. Background Technology

[0002] Shock absorbers cushion the impacts and vibrations experienced by motor vehicles during operation, ensuring a smooth and comfortable ride, and improving the vehicle's lifespan and handling stability. Painting, as a crucial step in the production of motorcycle shock absorbers, provides both protection and aesthetic appeal. With the younger generation choosing motorcycles (including electric two-wheelers) as their primary mode of transportation, environmentally friendly water-based paints that offer aesthetically pleasing finishes for motorcycle shock absorbers are particularly attractive to them and represent a promising market prospect.

[0003] Traditional aluminum alloy shock absorbers use solvent-based coatings, which have problems such as strong odor and high VOC emissions. Given the large scale of the aluminum alloy shock absorber industry, the environmental problems caused by high VOC emissions should not be underestimated.

[0004] Currently, most aluminum alloy shock absorber manufacturers are beginning to experiment with environmentally friendly water-based baking paint processes. This process can address the issue of high VOC emissions at the source, making it safer and more environmentally friendly. However, while existing water-based baking paints are safe and environmentally friendly, they generally suffer from problems such as poor water resistance, impact resistance, and poor adaptability to disc electrostatic spraying. Furthermore, most aluminum alloy shock absorber components do not undergo passivation treatment, and existing water-based baking paints, after curing, are easily permeable to oxygen and water, resulting in poor corrosion resistance and inadequate anti-corrosion protection for aluminum alloys. This makes it difficult to fully meet practical application requirements and severely restricts its widespread application.

[0005] Therefore, it is of great significance to develop a water-based baking paint with good water resistance, impact resistance, and disc application adaptability on unpassivated aluminum alloys and apply it to the coating of aluminum alloy shock absorbers. Summary of the Invention

[0006] To overcome the problems existing in the prior art, one objective of this invention is to provide a water-based baking paint for non-passivated aluminum alloy shock absorbers. A second objective of this invention is to provide a method for preparing the aforementioned water-based baking paint for non-passivated aluminum alloy shock absorbers. A third objective of this invention is the application of the aforementioned water-based baking paint for non-passivated aluminum alloy shock absorbers.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The first aspect of the present invention provides an aqueous paint for a non-passivated aluminum alloy shock absorber, the aqueous paint being prepared from raw materials comprising the following weight percentages: 35%–75% triblock waterborne polyester resin, 5%–10% tertiary amine compounds, 5%–15% amino resin, 0.2%–0.5% leveling agent, 0.2%–0.5% defoamer, 5%–30% pigment paste, 1%–15% film-forming aid, and 10%–40% water.

[0009] Preferably, the water-based paint used in the non-passivated aluminum alloy shock absorber is made from raw materials comprising the following weight percentages: 40%–60% triblock water-based polyester resin, 5%–8% tertiary amine compounds, 10%–15% amino resin, 0.2%–0.5% leveling agent, 0.2%–0.5% defoamer, 5%–20% pigment paste, 1%–5% film-forming aid, and 10%–40% water.

[0010] More preferably, the water-based paint for the non-passivated aluminum alloy shock absorber is made from the following raw materials in weight percentages: 40%–60% triblock water-based polyester resin, 5%–8% tertiary amine compounds, 10%–15% amino resin, 0.2%–0.5% leveling agent, 0.2%–0.5% defoamer, 5%–20% pigment paste, 1%–5% film-forming aid, and 10%–40% water.

[0011] Preferably, the triblock structured aqueous polyester resin is composed of polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol, polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol, and polyester segments with a number average molecular weight of 3000 g / mol to 5000 g / mol. The ratio range of each block is as follows: polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol account for 10%-30%, polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol account for 20%-30%, and polyester segments with a number average molecular weight of 3000 g / mol to 5000 g / mol account for 40%-60%.

[0012] More preferably, the polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol are obtained by polymerization of hexahydrophthalic anhydride or trimellitic anhydride with trimethylolpropane.

[0013] More preferably, the polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol are obtained by polymerization of adipic acid with diethylene glycol or methyl propylene glycol.

[0014] More preferably, the polyester segments with a number average molecular weight of 3000 g / mol to 5000 g / mol are obtained by polymerizing at least one of isophthalic acid, terephthalic acid, and trimellitic anhydride with neopentyl glycol.

[0015] More preferably, the triblock structured waterborne polyester resin is waterborne polyester resin 0155 from Qingtian Materials Technology Co., Ltd. and / or waterborne polyester resin 0264 from Qingtian Materials Technology Co., Ltd.

[0016] Preferably, the tertiary amine compound is one or more of N,N-dimethylethanolamine, 1-dimethylamino-2-propanol, and 3-dimethylamino-1-propanol.

[0017] Preferably, the amino resin is a fully methylated amino resin.

[0018] More preferably, the amino resin is a cyanide-based fully methylated amino resin.

[0019] Preferably, the leveling agent is one or a combination of TEGO4100, EFKA 3772.

[0020] Preferably, the defoamer is one or a combination of BYK 011, BYK 019, TEGO 830.

[0021] Preferably, the film-forming aid is one or a combination of isophorone, tripropylene glycol butyl ether, or the film-forming aid itself.

[0022] Preferably, the pigment paste is silver paste.

[0023] Preferably, the solid content of the pigment paste is 50wt%~70wt%.

[0024] The second aspect of the present invention provides a method for preparing water-based baking paint for the non-passivated aluminum alloy shock absorber described in the first aspect, comprising the following steps: mixing the raw materials to obtain water-based baking paint.

[0025] Preferably, the preparation method further includes the following step: filtering the mixed materials; the filter screen used for filtering has a pore size of 200 mesh to 300 mesh.

[0026] Preferably, the preparation method specifically includes the following steps: first, a triblock waterborne polyester resin and a tertiary amine compound are mixed, then an amino resin and a film-forming aid are added and mixed, then a leveling agent and a defoamer are added and mixed, then pigment paste and water are added and mixed, and finally the mixture is filtered to obtain a waterborne baking paint.

[0027] The third aspect of the present invention provides the application of water-based baking paint in the coating of automotive parts for the non-passivated aluminum alloy shock absorber described in the first aspect of the present invention.

[0028] Preferably, the automotive coating is a non-passivated aluminum alloy shock absorber coating.

[0029] Preferably, the water-based baking paint forms a paint film on the surface of the automotive parts, and the method for preparing the paint film is as follows: spraying the water-based baking paint onto the surface of the automotive parts and baking it at 140~180℃ for 20~30 minutes.

[0030] The beneficial effects of this invention are:

[0031] The water-based baking paint for the non-passivated aluminum alloy shock absorber of this invention has advantages such as good water resistance, good resistance to damp heat, good impact resistance, good adaptability to DISC application, good recoating properties, good storage stability, and safety and environmental friendliness. It is suitable for large-scale industrial application of DISC electrostatic spraying on non-passivated aluminum alloys. It not only solves the problem of poor corrosion resistance caused by the easy permeability of oxygen and water after curing of existing water-based baking paints, but also provides durable protection against long-term impacts on the shock absorber. Furthermore, the paint film formed by the curing of this invention has high brightness and fullness, achieving a good decorative effect.

[0032] In addition, the preparation method of the water-based baking paint for the non-passivated aluminum alloy shock absorber of the present invention is simple. The raw materials are mixed evenly in batches. Because a three-block structure water-based polyester resin is selected, it has good compatibility and dispersion of pigments, so no external dispersant is needed in the formula, which reduces the influence of dispersant on water boiling resistance. Moreover, the curing temperature is 140~180℃, which belongs to low temperature baking paint. Detailed Implementation

[0033] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels or prepared and isolated through simple synthesis; unless otherwise specified, the processes employed are conventional processes in the art.

[0034] In the following examples, the triblock structure of waterborne polyester resin 0155 and waterborne polyester resin 0264 is composed of polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol, polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol, and polyester segments with a number average molecular weight of 3000 g / mol to 5000 g / mol; the ratio range of each block is: the proportion of polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol is 10%-30%, and the proportion of polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol is 20%. %-30%, with polyester segments having a number average molecular weight of 3000 g / mol to 5000 g / mol accounting for 40%-60%; polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol are obtained by polymerization of hexahydrophthalic anhydride or trimellitic anhydride with trimethylolpropane; polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol are obtained by polymerization of adipic acid with diethylene glycol or methyl propylene glycol; and polyester segments with a number average molecular weight of 3000 g / mol to 5000 g / mol are obtained by polymerization of at least one of isophthalic acid, terephthalic acid, and trimellitic anhydride with neopentyl glycol.

[0035] Example 1:

[0036] A water-based baking paint for a non-passivated aluminum alloy shock absorber, the raw material composition of which is shown in Table 1 below:

[0037] Table 1. Raw material composition of water-based baking paint in Example 1

[0038]

[0039] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0040] Add waterborne polyester resin 0155 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent TEGO4100 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0041] Example 2:

[0042] A water-based baking paint for a non-passivated aluminum alloy shock absorber, the raw material composition of which is shown in Table 2 below:

[0043] Table 2. Raw material composition of water-based baking paint in Example 2

[0044]

[0045] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0046] Add waterborne polyester resin 0264 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent TEGO4100 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0047] Example 3:

[0048] A water-based baking paint for a non-passivated aluminum alloy shock absorber, the raw material composition of which is shown in Table 3 below:

[0049] Table 3. Raw material composition of water-based baking paint in Example 3

[0050]

[0051] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0052] Add waterborne polyester resin 0155 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent TEGO4100 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0053] Example 4:

[0054] A water-based baking paint for a non-passivated aluminum alloy shock absorber, the raw material composition of which is shown in Table 4 below:

[0055] Table 4. Raw material composition of water-based baking paint in Example 4

[0056]

[0057] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0058] Add waterborne polyester resin 0155 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent TEGO4100 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0059] Comparative Example 1:

[0060] A water-based baking paint, the raw material composition of which is shown in Table 5 below:

[0061] Table 5. Raw material composition of water-based baking paint in Comparative Example 1

[0062]

[0063] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0064] Add waterborne polyester resin TP9260 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent TEGO4100 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0065] Comparative Example 2:

[0066] A water-based baking paint, the raw material composition of which is shown in Table 6 below:

[0067] Table 6 Raw material composition of water-based baking paint in Comparative Example 2

[0068]

[0069] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0070] Add waterborne acrylic resin R174, waterborne polyester resin 0155 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent TEGO4100 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0071] Comparative Example 3:

[0072] A water-based baking paint, the raw material composition of which is shown in Table 7 below:

[0073] Table 7 Raw material composition of water-based baking paint in Comparative Example 3

[0074]

[0075] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0076] Add waterborne acrylic resin R174 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent EFKA 3772 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0077] Comparative Example 4:

[0078] A water-based baking paint, the raw material composition of which is shown in Table 8 below:

[0079] Table 8. Raw material composition of a water-based baking paint for an aluminum alloy shock absorber.

[0080]

[0081] The specific steps of the above-mentioned water-based baking paint preparation method are as follows:

[0082] Add waterborne acrylic resin R1055 and N,N-dimethylethanolamine to a mixing tank and mix thoroughly. Then, while stirring, add a mixture of fully methylated amino resin and isophorone and mix thoroughly. Next, while stirring, add leveling agent TEGO4100 and defoamer BYK 011 and mix thoroughly. Then, while stirring, add silver paste and deionized water and mix thoroughly. Finally, filter through a 200-mesh sieve to obtain waterborne baking paint.

[0083] To visually illustrate the differences between Examples 1-4 and Comparative Examples 1-4, the components of Examples 1-4 and Comparative Examples 1-104 are listed in Table 9:

[0084] Table 9 Summary of Raw Material Composition of Waterborne Baking Coatings in Examples 1-4 and Comparative Examples 1-4

[0085]

[0086] Performance testing:

[0087] The water-based baking paints of Examples 1-4 and Comparative Examples 1-4 were sprayed onto unpassivated aluminum alloys and baked at 150°C for 20 minutes. The thickness of the paint film was 15-25 micrometers. The performance of the formed paint film was then tested, and the test results are shown in Table 10 below.

[0088] Table 10 Performance test results of the paint film formed by baking water-based baking paint at 150℃ for 20 min

[0089]

[0090] Note:

[0091] Hardness: Tested according to "GB / T 6739-2022 Pencil Hardness Test for Coatings";

[0092] Impact strength: Tested according to "GB / T 1732-2020 Test method for impact resistance of coatings";

[0093] Disc electrostatic spraying workability: Using a 101 spray gun, with one atomization cycle, atomization pressure of 0.2 MPa, and flow rate of one cycle, the maximum distance that can be sprayed when the spray gun is spraying horizontally is calculated in cm.

[0094] Recoating adhesion: Tested according to "GB / T9286-88 Test method for paint film adhesion";

[0095] Abrasion resistance: Tested according to "GB / T 1768-1979(1989) Test method for abrasion resistance of paint film";

[0096] Resistance to methyl ethyl ketone (MEK): Tested according to "GB / T 23989-2009 Determination of Solvent Resistance of Coatings by Wiping".

[0097] Resistance to damp heat: Tested according to "GB 1740-1979(1989) Test method for resistance to damp heat of paint film";

[0098] Thermal cycling resistance: 60℃×2h to -40℃×2h, 10 cycles;

[0099] Gloss: Tested according to "GB 1743-1979(1989) Test Method for Gloss of Coating Film";

[0100] QUV resistance for 1200h: Tested according to "ISO4892-3:1194";

[0101] Acid resistance: Tested according to "GB / T 9274-1988 Determination of resistance to liquid media for paints and varnishes";

[0102] Alkali resistance: Tested according to "GB / T 9274-1988 Determination of resistance to liquid media for paints and varnishes".

[0103] As shown in Table 10:

[0104] a) The water-based baking paints of Examples 1 to 4 have an impact strength of 50 and a water resistance of 60°C for 120 hours, which can meet the application requirements on non-passivated aluminum alloys. However, the water-based baking paints of Comparative Examples 1 to 4 have an impact strength of less than 50 and poor water resistance of 60°C, which cannot meet the application requirements on non-passivated aluminum alloys.

[0105] b) The water-based baking paints of Examples 1 to 4 all passed the tests for acid resistance, alkali resistance and damp heat resistance, while the water-based baking paint of Comparative Example 1 failed the alkali resistance test, the water-based baking paint of Comparative Example 4 failed the acid resistance test, and the water-based baking paints of Comparative Examples 1 to 4 failed the impact strength test and had poor damp heat resistance.

[0106] The water-based baking paint for the non-passivated aluminum alloy shock absorber of the present invention has advantages such as good water resistance, good impact resistance, good adaptability to DISC construction, good recoating properties, good storage stability, and safety and environmental protection. Moreover, the cured paint film has high brightness and fullness, good toughness and hardness, good scratch resistance and impact resistance, good high temperature and humidity resistance and thermal cycling resistance, good weather resistance and acid and alkali resistance, and good appearance decoration effect, making it suitable for large-scale industrial application of DISC electrostatic spraying.

[0107] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A waterborne baking finish for unpas sivated aluminum alloy shock absorbers, characterized in that, The non-passivated aluminum alloy shock absorber is made from the following raw materials in weight percentages: 40%–60% triblock waterborne polyester resin, 5%–8% tertiary amine compounds, 10%–15% amino resin, 0.2%–0.5% leveling agent, 0.2%–0.5% defoamer, 5%–20% pigment paste, 1%–5% film-forming aid, and 10%–40% water; The triblock structured aqueous polyester resin is composed of polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol, polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol, and polyester segments with a number average molecular weight of 3000 g / mol to 5000 g / mol. The polyester segments with a number average molecular weight of 500 g / mol to 1000 g / mol are obtained by polymerization of hexahydrophthalic anhydride or trimellitic anhydride with trimethylolpropane. The polyester segments with a number average molecular weight of 1000 g / mol to 2000 g / mol are obtained by polymerization of adipic acid with diethylene glycol or methyl propylene glycol; The polyester segments with a number average molecular weight of 3000 g / mol to 5000 g / mol are obtained by polymerizing at least one of isophthalic acid, terephthalic acid, and trimellitic anhydride with neopentyl glycol.

2. The waterborne baking paint for non-passivated aluminum alloy shock absorbers according to claim 1, characterized by, The tertiary amine compound is one or more of N,N-dimethylethanolamine, 1-dimethylamino-2-propanol, and 3-dimethylamino-1-propanol.

3. The waterborne baking paint for non-passivated aluminum alloy shock absorbers according to claim 1, characterized by, The amino resin is a fully methylated amino resin.

4. The waterborne baking paint for non-passivated aluminum alloy shock absorbers according to claim 1, characterized by, The film-forming aid is one or a combination of isophorone, tripropylene glycol butyl ether, or the film-forming aid itself.

5. The process for the production of a waterborne baking finish for unpassivated aluminium alloy shock absorbers according to any one of claims 1 to 4, characterized in that, The process includes the following steps: mixing the raw materials to obtain a water-based baking paint.

6. The process for the preparation of a waterborne baking finish for non-passivated aluminium alloy shock absorbers according to claim 5, characterized in that, It also includes the following steps: filtering the mixed materials to obtain water-based baking paint; The filter used in the filtration process has a mesh size of 200 to 300 mesh.

7. The application of water-based baking paint in the coating of automotive parts for the non-passivated aluminum alloy shock absorber as described in any one of claims 1 to 4.

8. Use of a waterborne baking paint for passivation-free aluminium alloy shock absorbers according to claim 7, characterized in that, The water-based baking paint forms a paint film on the surface of automotive parts, and the film-forming and curing temperature of the water-based baking paint is 140-180℃.

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