Single-coating scratch-resistant repairable PU frosted black paint as well as preparation method and construction method of single-coating scratch-resistant repairable PU frosted black paint

Abstract

The invention particularly relates to a single-coating scratch-resistant repairable PU (polyurethane) frosted black paint as well as a preparation method and a construction method of the single-coating scratch-resistant repairable PU frosted black paint. The single-coated scratch-resistant repairable PU frosted black paint is composed of a component A, a component B and a diluent in a mass ratio of (4-6): 1: (4-6), the component A is prepared from the following raw materials in parts by mass: low-hydroxyl-value acrylic resin, medium-high-hydroxyl-value acrylic resin, high-hydroxyl-value acrylic resin, an ester solvent, a ketone solvent, carbon powder, a dispersing agent, polytetrafluoroethylene modified polyethylene wax, silicone wear-resistant powder, modified polydimethylsiloxane, barium sulfate and Shanghai Xingreputation chemical L3027 modified FEVE fluorocarbon resin; the component B comprises the following raw materials in parts by mass: a curing agent and butyl acetate. A coating formed by the paint has the characteristics of no cracking at high and low temperatures, high adhesive force, high hardness, high wear resistance, high scratch resistance, high weather resistance, water resistance, chemical resistance, heat and humidity resistance and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and particularly relates to a single - coat scratch - resistant and repairable PU matte black paint, its preparation method and construction method. Background Art

[0002] In today's digital age, 3C electronic products, with their remarkable characteristics of being lightweight and easy to carry, have won extremely high favor among the vast consumer groups. With the continuous improvement of consumers' requirements for product appearance and quality, the coating requirements for the casings of 3C electronic products such as laptops and tablet computers are also increasing day by day. The casing coating should not only have the function of protecting the product, but also have an attractive appearance, good touch and long - lasting durability.

[0003] Currently, among the coatings used for the casing coating of 3C electronic products in the market, PU (polyurethane) series coatings occupy a relatively large market share. However, there are some problems that need to be solved urgently in this series of coatings. For example, when the gloss - dullness is less than 2°, the formed coating is easily scratched and cannot be self - repaired. In addition, it is very difficult for the existing PU series coatings to meet the current customers' requirements for product performance in terms of hardness, abrasion resistance and other performance indicators.

[0004] To address the above problems, many coating manufacturers adopt the construction process of spraying a PU primer and then covering it with a PU topcoat. This process improves the scratch - resistant performance of the product to a certain extent by covering a topcoat on the primer. However, the secondary spraying operation increases the production time and cost, reduces the production efficiency, and emits more organic solvents, causing greater pollution to the environment.

[0005] Therefore, considering from the perspectives of production efficiency, energy conservation and environmental protection, there is an urgent need for a single - coat scratch - resistant and repairable PU matte black paint to replace the currently used double - coat paint. This paint needs to meet the high requirements for the casing coating of 3C electronic products, and at the same time avoid the problems of resource waste and environmental pollution of the double - coat paint. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a single - coat scratch - resistant and repairable PU matte black paint, its preparation method and construction method. The coating formed by this paint has the characteristics of not cracking at high and low temperatures, high adhesion, high hardness, high abrasion - resistant scratch resistance, high weather resistance, water resistance, chemical resistance, heat and humidity resistance, etc.

[0007] The technical solution adopted by the present invention to solve the above problems is as follows:

[0008] A single - coat scratch - resistant and repairable PU matte black paint is composed of component A, component B and a diluent with a mass ratio of (4 - 6):1:(4 - 6);

[0009] The component A comprises the following raw materials by mass: 8-12 parts of low hydroxyl value acrylic resin, 30-40 parts of medium-high hydroxyl value acrylic resin, 4-6 parts of high hydroxyl value acrylic resin, 12-22 parts of ester solvent, 10-16 parts of ketone solvent, 2-4 parts of carbon powder, 2-4 parts of dispersant, 1-3 parts of polytetrafluoroethylene modified polyethylene wax, 4-6 parts of silicone wear-resistant powder, 0.1-0.3 parts of modified polydimethylsiloxane, 2-4 parts of barium sulfate, and 3-5 parts of Shanghai Shuyu Chemical L3027 modified FEVE fluorocarbon resin;

[0010] The B component includes the following raw materials in parts by mass: 55 to 65 parts of a curing agent and 35 to 45 parts of butyl acetate.

[0011] Preferably, the hydroxyl value of the low hydroxyl value acrylic resin is 30-50.

[0012] Specifically, the low hydroxyl value acrylic resin includes but is not limited to Yak YH2205.

[0013] Preferably, the hydroxyl value of the medium-high hydroxyl value acrylic resin is 60-80.

[0014] Specifically, the medium-high hydroxyl value acrylic resin includes but is not limited to Yak YZ-H764.

[0015] Preferably, the hydroxyl value of the high hydroxyl value acrylic resin is 140-160.

[0016] Specifically, the high hydroxyl value acrylic resin includes but is not limited to KN3263F.

[0017] Furthermore, the ketone solvent is composed of butanone and diacetone alcohol (DAA) in a mass ratio of (4-6): (1-2).

[0018] Furthermore, the ester solvent is composed of propylene glycol methyl ether acetate (PMA) and butyl ester in a mass ratio of (4-6): (3-5).

[0019] Specifically, the carbon powder includes but is not limited to 6# carbon powder.

[0020] Specifically, the dispersant includes but is not limited to BYK163.

[0021] Specifically, the polytetrafluoroethylene modified polyethylene wax is TF1778.

[0022] Specifically, the silicone wear-resistant powder is SIC 6003S.

[0023] Specifically, the modified polydimethylsiloxane is PEG-12.

[0024] Further, in the B component, the curing agent is prepared by mixing N3390 and N3790 in a mass ratio of 1:1.

[0025] Further, the diluent comprises the following raw materials in parts by mass: 18 - 22 parts of butyl acetate, 8 - 12 parts of propylene glycol methyl ether acetate (PMA), 18 - 22 parts of propylene glycol methyl ether (PM), 30 - 40 parts of ethyl acetate, and 12 - 18 parts of methyl ethyl ketone.

[0026] Further, the preparation method of the single - coat scratch - resistant and repairable PU matte black paint comprises the following steps:

[0027] S1. Prepare the A component: First, add medium - high hydroxyl - value acrylic resin, high - hydroxyl - value acrylic resin, and low - hydroxyl - value acrylic resin, and then stir; add ketone solvents and ester solvents, and stir at a stirring speed of 300 - 400 r / min; add carbon powder and dispersant, and stir at a stirring speed of 300 - 400 r / min; then add polytetrafluoroethylene - modified polyethylene wax, silicone wear - resistant powder, modified polydimethylsiloxane, barium sulfate, and Shanghai Shuyu Chemical L3027 - modified FEVE fluorocarbon resin, and then stir at a stirring speed of 800 - 1000 r / min; grind in a sand mill until the fineness reaches 10 - 12 microns;

[0028] S2. Prepare the B component: At a stirring speed of 300 - 400 r / min, add the curing agent and butyl acetate to the stirring kettle in sequence, and then stir at a stirring speed of 500 - 600 r / min for 20 minutes;

[0029] S3. Prepare the C component: Feed materials according to the weight - part ratio of the formula, and stir at 300 - 400 r / min for 5 minutes.

[0030] A construction method of the single - coat scratch - resistant and repairable PU matte black paint comprises the following steps: Dilute according to the weight ratio of A component: B component: diluent=(4 - 6):1:(4 - 6), and the viscosity is 9.0 - 9.5 seconds; then spray, and the spray film thickness is 15 - 20 μm; then bake at 70 - 80 °C for 60 - 120 min.

[0031] The present invention has the following beneficial effects:

[0032] The single - coated scratch - resistant and repairable PU matte black paint of the present invention is composed of component A, component B and a diluent. Component A uses silicone wear - resistant powder, modified polydimethylsiloxane and Shanghai Shuyu Chemical L3027 modified FEVE fluorocarbon resin, which can provide scratch resistance inside the paint film and the paint film repair performance. Barium sulfate and polytetrafluoroethylene - modified polyethylene wax are used to provide the surface hardness of the paint film. In component B, a hydroxyl - acrylic main resin is selected to provide excellent scratch resistance for the paint film. At the same time, in the diluent, hexamethylene diisocyanate with excellent elasticity and flexibility and toluene diisocyanate with relatively fast drying are selected and paired as the curing agent component, which can be paired with component A to achieve the optimal performance.

[0033] The coating formed by the paint of the present invention has the characteristics of non - cracking at high and low temperatures, high adhesion, high hardness, high wear - and scratch - resistance, high weather resistance, water resistance, chemical resistance, and heat - humidity resistance. In addition, the paint of the present invention is a single - layer one - coat paint, which can cover the paint film surface well, and is superior to the primer - coated PU transparent matte two - coat paint film on the market. The film thickness of the coating is reduced, and the cost is more saved. Detailed implementation mode

[0034] To make the technical problems, technical solutions and technical advantages to be solved by the present invention clearer, the following will be described in detail with specific examples. However, the protection scope of the present invention is not limited to the following specific embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, and even less a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0035] Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0036] A single - coated scratch - resistant and repairable PU matte black paint is composed of component A, component B and a diluent with a mass ratio of (4 - 6):1:(4 - 6).

[0037] Component A includes the following raw materials by mass fraction: 8 - 12 parts of low - hydroxyl - value acrylic resin, 30 - 40 parts of medium - high - hydroxyl - value acrylic resin, 4 - 6 parts of high - hydroxyl - value acrylic resin, 12 - 22 parts of ester solvent, 10 - 16 parts of ketone solvent, 2 - 4 parts of carbon powder, 2 - 4 parts of dispersant, 1 - 3 parts of polytetrafluoroethylene - modified polyethylene wax, 4 - 6 parts of silicone wear - resistant powder, 0.1 - 0.3 parts of modified polydimethylsiloxane, 2 - 4 parts of barium sulfate, and 3 - 5 parts of Shanghai Shuyu Chemical L3027 modified FEVE fluorocarbon resin.

[0038] The component B comprises the following raw materials by mass parts: 55 - 65 parts of curing agent and 35 - 45 parts of butyl acetate.

[0039] In some preferred embodiments, the hydroxyl value of the low-hydroxyl-value acrylic resin is 30 - 50.

[0040] Specifically, the low-hydroxyl-value acrylic resin includes but is not limited to Jacques YH2205.

[0041] In some preferred embodiments, the hydroxyl value of the medium-high-hydroxyl-value acrylic resin is 60 - 80.

[0042] Specifically, the medium-high-hydroxyl-value acrylic resin includes but is not limited to Jacques YZ-H764.

[0043] In some preferred embodiments, the hydroxyl value of the high-hydroxyl-value acrylic resin is 140 - 160.

[0044] Specifically, the high-hydroxyl-value acrylic resin includes but is not limited to Collison KN3263F.

[0045] In some embodiments, the ketone solvent is composed of methyl ethyl ketone and diacetone alcohol (DAA) with a mass ratio of (4 - 6):(1 - 2).

[0046] In some embodiments, the ester solvent is composed of propylene glycol monomethyl ether acetate (PMA) and butyl ester with a mass ratio of (4 - 6):(3 - 5).

[0047] Specifically, the toner includes but is not limited to No. 6 toner.

[0048] Specifically, the dispersant includes but is not limited to BYK163.

[0049] Specifically, the polytetrafluoroethylene-modified polyethylene wax is TF1778.

[0050] Specifically, the silicone wear-resistant powder is SIC 6003S.

[0051] Specifically, the modified polydimethylsiloxane is PEG-12.

[0052] In some embodiments, in the component B, the curing agent is prepared by mixing N3390 and N3790 in a mass ratio of 1:1.

[0053] In some embodiments, the diluent comprises the following raw materials by mass parts: 18 - 22 parts of butyl acetate, 8 - 12 parts of propylene glycol monomethyl ether acetate (PMA), 18 - 22 parts of propylene glycol monomethyl ether (PM), 30 - 40 parts of ethyl acetate, and 12 - 18 parts of methyl ketone.

[0054] In some embodiments, the preparation method of the single-coat scratch-resistant and repairable PU matte black paint comprises the following steps:

[0055] S1. Prepare Component A: First, add medium-high hydroxyl value acrylic resin, high hydroxyl value acrylic resin, and low hydroxyl value acrylic resin, and then stir; add ketone solvent and ester solvent, and stir at a stirring speed of 300 - 400 r / min; add carbon powder and dispersant, and stir at a stirring speed of 300 - 400 r / min; then add polytetrafluoroethylene-modified polyethylene wax, silicone wear-resistant powder, modified polydimethylsiloxane, barium sulfate, and Shanghai Shuyu Chemical L3027-modified FEVE fluorocarbon resin, and then stir at a stirring speed of 800 - 1000 r / min; grind in a sand mill until the fineness reaches 10 - 12 microns;

[0056] S2. Prepare Component B: At a stirring speed of 300 - 400 r / min, add a curing agent and butyl acetate to a stirring kettle in sequence, and then stir at a stirring speed of 500 - 600 r / min;

[0057] S3. Prepare Component C: Charge according to the formula weight parts and stir at a stirring speed of 300 - 400 r / min.

[0058] In some embodiments, the construction method of the single-coat scratch-resistant and repairable PU matte black paint comprises the following steps: Dilute according to the weight ratio of Component A: Component B: thinner = (4 - 6):1:(4 - 6), and the viscosity is 9.0 - 9.5 seconds; then spray, and the spray film thickness is 15 - 20 μm; subsequently, bake at 70 - 80 °C for 60 - 120 min.

[0059] The following Examples 1 - 3 respectively provide a single-coat scratch-resistant and repairable PU matte black paint, and the content of each component is shown in Table 1.

[0060] Table 1:

[0061]

[0062]

[0063] The preparation method of the single-coat scratch-resistant and repairable PU matte black paint in the above Examples 1 - 3 comprises the following steps:

[0064] S1. Prepare Component A: First, add medium-high hydroxyl value acrylic resin, high hydroxyl value acrylic resin, and low hydroxyl value acrylic resin, and then stir; add ketone solvents and ester solvents, and stir at a stirring speed of 400 r / min for 3 min; add carbon powder and dispersant, and stir at a stirring speed of 400 r / min for 5 min; then add polytetrafluoroethylene modified polyethylene wax TF-1778, silicone wear-resistant powder SIC 6003S, modified polydimethylsiloxane PEG-12, barium sulfate, and Shanghai Shuyu Chemical L3027 modified FEVE fluorocarbon resin, and then stir at a stirring speed of 1000 r / min for 20 min; grind in a sand mill until the fineness reaches 10 - 12 microns;

[0065] S2. Prepare Component B: At a stirring speed of 400 r / min, add the curing agent and butyl acetate to the stirring kettle in sequence, and then stir at a stirring speed of 600 r / min for 20 min;

[0066] S3. Prepare Component C: Feed according to the formula weight parts, and stir at a stirring speed of 400 r / min for 5 min.

[0067] The single-coated scratch-resistant and repairable PU matte black paint in the above three examples can all achieve the following properties:

[0068] 1. Storage stability of the paint: The storage period is 1 year

[0069] 2. Evaluation of construction application: Suitable for construction, one-time spraying forming, good drying property at 70 - 80 °C * 60 - 120 minutes.

[0070] To evaluate the technical effects of the present invention, the paint films formed after the construction of the single-coated scratch-resistant and repairable PU matte black paint in Examples 1 - 3 were tested. The construction method is as follows:

[0071] By weight ratio, Component A: Component B: Diluent = 5:1:5 for dilution, adjust the viscosity to 9.0 - 9.5 seconds; then spray on the ABS+PC material, and the spray film thickness is 15 - 20 μm; then bake at 70 °C for 80 min.

[0072] The paint films in Examples 1 - 3 were tested. The specific test results of the paint films in Examples 1 - 3 are as follows:

[0073] (1) Scratch resistance test: 318 anti-scratch pen, no white lines / color change at all angles with 2 N, and no obvious scratching of the paint film with 9 N.

[0074] (2) After being slightly scratched by hand, the scratch can be significantly repaired within 1 hour at room temperature.

[0075] (3) Chemical test: 99.5% alcohol, rubbed 200 times, no obvious damage to the paint film, and the gray scale of the felt is Grade 2.

[0076] (4) Hydrolysis resistance (60℃ * 95% * 240H): No blistering, no whitening, and the adhesion is 100%.

[0077] (5) Light exposure test: Temperature scale 90℃, irradiance (48 - 100) W / Mm 2 (300 - 400), the test energy is 250MJ, result: The adhesion is 100%, and the gray scale of the sample is greater than or equal to Grade 4.

[0078] (6) Adhesion (cross - cut method / 3M - 600 adhesive tape 5 times): 100%.

[0079] (7) High - temperature resistance test: 90℃ * 500 hours, the adhesion is qualified, and there is no obvious abnormality in the appearance of the paint film.

[0080] (8) High - low temperature shock: First, place the specimen at a temperature of (-40 ± 3)℃ for 12h, then take out the specimen and place it at room temperature, let it stand for 30min, and then place it in a high - temperature oven at 85 ± 3℃ for 12h, then take it out and let it stand for 30min; Take 24 hours as a cycle and do 10 cycles, check the surface state of the specimen and test the adhesion; There are no obvious change defects such as peeling, cracking, and blistering, and the adhesion is Grade 0 or Grade 1.

[0081] It can be known from the experimental data that the coatings formed in Examples 1 - 3 have the characteristics of no cracking at high and low temperatures, high adhesion, high hardness, high wear and scratch resistance, high weather resistance, water resistance, chemical resistance, and heat and humidity resistance.

[0082] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above - mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0083] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above - mentioned specific embodiments can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not describe various possible combination methods separately.

[0084] In addition, any combination can be made between different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A single-coat scratch-resistant and repairable PU matte black paint, characterized in that: It is composed of component A, component B and a diluent in a mass ratio of (4-6):1:(4-6); The component A comprises the following raw materials by mass: 8-12 parts of low hydroxyl value acrylic resin, 30-40 parts of medium-high hydroxyl value acrylic resin, 4-6 parts of high hydroxyl value acrylic resin, 12-22 parts of ester solvent, 10-16 parts of ketone solvent, 2-4 parts of carbon powder, 2-4 parts of dispersant, 1-3 parts of polytetrafluoroethylene modified polyethylene wax, 4-6 parts of silicone wear-resistant powder, 0.1-0.3 parts of modified polydimethylsiloxane, 2-4 parts of barium sulfate, and 3-5 parts of Shanghai Shuyu Chemical L3027 modified FEVE fluorocarbon resin; The B component includes the following raw materials in parts by mass: 55 to 65 parts of a curing agent and 35 to 45 parts of butyl acetate.

2. The single-coat scratch-resistant repairable PU matte black paint according to claim 1, characterized in that: The hydroxyl value of the low hydroxyl value acrylic resin is 30-50.

3. The single-coat scratch-resistant repairable PU matte black paint according to claim 1, characterized in that: The hydroxyl value of the medium-high hydroxyl value acrylic resin is 60-80.

4. The single-coat scratch-resistant repairable PU matte black paint according to claim 1, characterized in that: The hydroxyl value of the high hydroxyl value acrylic resin is 140-160.

5. The single-coat scratch-resistant repairable PU matte black paint according to claim 1, characterized in that: The ketone solvent is composed of butanone and diacetone alcohol in a mass ratio of (4-6):(1-2).

6. The single-coat scratch-resistant repairable PU matte black paint according to claim 1, characterized in that: The ester solvent is composed of propylene glycol methyl ether acetate and butyl ester in a mass ratio of (4-6): (3-5).

7. The single-coat scratch-resistant repairable PU matte black paint according to claim 1, characterized in that: In the B component, the curing agent is a mixture of N3390 and N3790 in a mass ratio of 1:

1.

8. The single-coat scratch-resistant repairable PU matte black paint according to claim 1, characterized in that: The diluent comprises the following raw materials in parts by mass: 18 to 22 parts of butyl acetate, 8 to 12 parts of propylene glycol methyl ether acetate, 18 to 22 parts of propylene glycol methyl ether, 30 to 40 parts of ethyl acetate, and 12 to 18 parts of ketone.

9. A method for preparing the single-coat scratch-resistant repairable PU matte black paint according to any one of claims 1 to 8, characterized in that: The steps include: S1. Prepare component A: first add medium-high hydroxyl value acrylic resin, high hydroxyl value acrylic resin, and low hydroxyl value acrylic resin, and then stir; add ketone solvents and ester solvents, and stir at a stirring speed of 300 to 400 r / min; add carbon powder and dispersant, and stir at a stirring speed of 300 to 400 r / min; then add polytetrafluoroethylene modified polyethylene wax, silicone wear-resistant powder, modified polydimethylsiloxane, barium sulfate, Shanghai Shuyu Chemical L3027 modified FEVE fluorocarbon resin, and then stir at a stirring speed of 800 to 1000 r / min; grind in a sand mill to a fineness of 10 to 12 microns; S2. Preparation of component B: adding a curing agent and butyl acetate sequentially to a stirring kettle at a stirring speed of 300 to 400 r / min, and then stirring at a stirring speed of 500 to 600 r / min; S3. Prepare component C: add materials according to the formula weight and stir at a stirring speed of 300 to 400 r / min.

10. A construction method of a single-coat scratch-resistant repairable PU matte black paint according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: thinning the composition by weight, component A: component B: diluent = (4-6): 1: (4-6), with a viscosity of 9.0-9.5 seconds; spraying, with a spraying film thickness of 15-20 μm; and subsequently baking at 70-80° C. for 60-120 minutes.

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