High-hardness high-gloss PU (polyurethane) varnish for musical instruments and preparation method of high-hardness high-gloss PU varnish

Abstract

The invention provides a high-hardness high-gloss PU (polyurethane) varnish for musical instruments and a preparation method thereof, and belongs to the technical field of high-gloss varnish, the high-hardness high-gloss PU varnish comprises a main agent, a curing agent and a diluent, the main agent comprises the following components in percentage by weight: 25-35% of synthetic fatty acid alkyd resin, 45-55% of modified acrylic resin, 8-12% of polyaldehyde resin, 0.4-0.6% of a defoaming agent, 0.8-1.1% of a flatting agent, 4-5% of a solvent and 0.3-0.5% of a drier. According to the PU high-hardness bright top-coat for musical instruments and the preparation method thereof, the purposes of no prickly heat, fast hardness increase and high paint film hardness during high-temperature thick coating in summer are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of bright finish paints, and particularly relates to a PU high-hardness bright finish paint for musical instruments and a preparation method thereof. Background Art

[0002] With the development of society, humans have higher and higher requirements for the coating effects of Chinese classical musical instruments, and consumers pursue the fullness and high-transparency decoration of the coating film. Musical instruments coated with bright finish paint present a beautiful and full visual effect, vividly demonstrating the simple and lively modern fashion atmosphere, enhancing the value sense of the musical instruments, bringing consumers a unique noble enjoyment and the taste of pursuing a healthy life, and being deeply favored by the market and loved by customers. The demand for bright finish paint in the musical instrument market has increased sharply in the past one or two years, and it is mainly used for high-grade musical instruments such as guzheng, pipa, guqin, piano, guitar, etc.

[0003] The invention patent with the publication number CN109294449A and the name "A paint for musical instruments" discloses the following raw materials: color powder, polyquaternium-7, turpentine, varnish, sequins, paint additives. In the above invention, methyl silicone oil has a relatively high flash point and ignition point, and excellent heat resistance, electrical insulation, weather resistance, and hydrophobicity, which can improve the heat resistance and insulation imitation activity of the paint, and the raw materials are safe, environmentally friendly, and non-toxic; bamboo leaf powder has antibacterial effects, and at the same time, bamboo leaf powder and diatomite can absorb formaldehyde in the paint to a certain extent, playing a role in purifying the air. However, although the paint in the above technical solution has the characteristics of varnish and brightness, it cannot meet the market needs in terms of hand feeling, high hardness, and no prickly heat when thickly coated. Summary of the Invention

[0004] In view of this, the present invention provides a PU high-hardness bright finish paint for musical instruments and a preparation method thereof, achieving the purpose of no prickly heat when thickly coated in high temperature in summer, rapid increase in hardness, and high film hardness.

[0005] To achieve the above purpose, the present invention provides a PU high-hardness bright finish paint for musical instruments, which includes a main agent, a curing agent, and a diluent. The main agent includes the following components in weight percentages: synthetic fatty acid alkyd resin 25 - 35%, modified acrylic resin 45 - 55%, polyaldehyde resin 8 - 12%, defoaming agent 0.4 - 0.6%, leveling agent 0.8 - 1.1%, solvent 6 - 9%, drier 0.3 - 0.5%.

[0006] Optionally, the curing agent includes the following components in mass percentages: TDI trimer 10 - 15%, L-75 adduct 60 - 70%, butyl acetate 20 - 30%.

[0007] Optionally, the diluent includes the following components in mass percentages: xylene 30 - 50%, propylene glycol methyl ether acetate 10 - 30%, butyl acetate 20 - 40%.

[0008] Optionally, the solvent is butyl acetate and propylene glycol methyl ether acetate.

[0009] Optionally, the solvent comprises components in the following weight percentages: 3-4% of butyl acetate and 3.5-4.5% of propylene glycol methyl ether acetate.

[0010] Optionally, the leveling agent is a fluorocarbon-modified acrylic leveling agent and a polyether-modified polymethylsiloxane leveling agent.

[0011] Optionally, the leveling agent comprises components in the following weight percentages: 0.7-0.9% of fluorocarbon-modified acrylic leveling agent and 0.1-0.2% of polyether-modified polymethylsiloxane leveling agent.

[0012] Optionally, the weight ratio of the main agent, curing agent and diluent is 1:1:0.5-0.7.

[0013] To achieve the above object, the present invention also provides a preparation method of a PU high-hardness bright finish paint for musical instruments, comprising the following steps: mixing synthetic fatty acid alkyd resin, modified acrylic resin and polyaldehyde resin and stirring at a low speed, and then adding an antifoaming agent, a leveling agent, a solvent and a drier and stirring at a high speed to obtain the product.

[0014] Optionally, the low-speed stirring is at a rotation speed of 600-800 r / min for 8-12 min; the high-speed stirring is at a rotation speed of 1000-1200 r / min for 8-12 min.

[0015] The above technical solution of the present invention has at least the following beneficial effects: In the technical solution of the present invention, special modified acrylic acid is used to improve the anti-prickly heat and hardness of the paint film; the polyaldehyde resin contains a carbonyl group in its molecular structure and a hydroxyl group at the end, and after being mixed with the modified acrylic resin containing a hydroxyl-group special monomer and the synthetic fatty acid alkyd resin, it acts together, has good compatibility with the solvent, and can effectively improve the initial drying property, adhesion, hardness, light retention property and other properties of the paint, so that the formed paint film has good oil resistance, chemical resistance and weather resistance; the synthetic fatty acid alkyd resin also plays a role in improving the fullness of the paint film. The fluorocarbon-modified acrylic leveling agent used in the technical solution of the present invention promotes leveling, improves substrate wetting, and does not affect the interlayer adhesion; the polyether-modified polymethylsiloxane leveling agent prevents shrinkage holes and increases the surface smoothness. Detailed Embodiments

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0017] Example 1 A high-hardness bright PU clear topcoat for musical instruments, comprising a main agent, a curing agent, and a thinner. The main agent comprises the following components in weight percentages: 30% of synthetic fatty acid alkyd resin, 50% of modified acrylic resin, 10% of polyaldehyde resin, 0.5% of defoaming agent, 0.2% of polyether-modified polymethylsiloxane leveling agent and 0.8% of fluorocarbon-modified acrylic leveling agent as leveling agents, 3.5% of butyl acetate and 4.6% of propylene glycol methyl ether acetate as solvents, and 0.4% of drier.

[0018] The curing agent comprises the following components in weight percentages: 10% of TDI trimer, 65% of L-75 adduct, and 25% of butyl acetate.

[0019] The thinner comprises the following components in mass percentages: 40% of xylene, 30% of propylene glycol methyl ether acetate, and 30% of butyl acetate The weight ratio of the main agent, the curing agent, and the thinner is 1:1:0.5.

[0020] Among them, the raw material models are as follows: the synthetic fatty acid alkyd resin is TIRES 2848YA resin; the modified acrylic resin is MFRC-5550YT; the polyaldehyde resin is 70% CR-2100 polyaldehyde resin; the defoaming agent is BYK141; the polyether-modified polymethylsiloxane leveling agent is BYK-333, and the fluorocarbon-modified acrylic leveling agent is EFKA3777N; the drier is T-12; the L-75 adduct is L-75E; there are no requirements for the models of butyl acetate, propylene glycol methyl ether acetate, TDI trimer, and xylene.

[0021] The preparation method is to mix the synthetic fatty acid alkyd resin, the modified acrylic resin, and the polyaldehyde resin and stir at a low speed. The low-speed stirring is at a rotation speed of 700 r / min for 10 min; then add the defoaming agent, the leveling agent, the solvent, and the drier and stir at a high speed. The high-speed stirring is at a rotation speed of 1100 r / min for 10 min, and it is obtained after the mixing and stirring are completed.

[0022] Example 2 A PU high-hardness bright finish paint for musical instruments, comprising a main agent, a curing agent and a thinner. The main agent comprises the following components in weight percentages: synthetic fatty acid alkyd resin 25%, modified acrylic resin 55%, polyaldehyde resin 9%, defoamer 0.5%, leveling agents being polyether-modified polymethylsiloxane leveling agent 0.1% and fluorocarbon-modified acrylic leveling agent 0.9%, solvents being butyl acetate 4% and propylene glycol methyl ether acetate 5%, and drier 0.5%.

[0023] The curing agent comprises the following components in weight percentages: TDI trimer 15%, L-75 adduct 60%, and butyl acetate 25%.

[0024] The thinner comprises the following components in mass percentages: xylene 50%, propylene glycol methyl ether acetate 10%, and butyl acetate 40%.

[0025] The weight ratio of the main agent, the curing agent and the thinner is 1:1:0.7.

[0026] Among them, the raw material models are as follows: the synthetic fatty acid alkyd resin is TIRES 2848YA resin; the modified acrylic resin is MFRC-5550YT; the polyaldehyde resin is 70% CR-2100 polyaldehyde resin; the defoamer is BYK141; the polyether-modified polymethylsiloxane leveling agent is BYK-333, and the fluorocarbon-modified acrylic leveling agent is EFKA3777N; the drier is T-12; the L-75 adduct is L-75E; there are no requirements for the models of butyl acetate, propylene glycol methyl ether acetate, TDI trimer and xylene.

[0027] The preparation method is to mix the synthetic fatty acid alkyd resin, the modified acrylic resin and the polyaldehyde resin and stir at a low speed. The low-speed stirring is at a rotation speed of 600 r / min for 12 min; then add the defoamer, the leveling agents, the solvents and the drier and stir at a high speed. The high-speed stirring is at a rotation speed of 1200 r / min for 8 min, and it is obtained after the mixing and stirring are completed.

[0028] Example 3 A PU high-hardness bright finish paint for musical instruments, comprising a main agent, a curing agent and a thinner. The main agent comprises the following components in weight percentages: synthetic fatty acid alkyd resin 25%, modified acrylic resin 55%, polyaldehyde resin 12%, defoamer 0.6%, leveling agents being polyether-modified polymethylsiloxane leveling agent 0.1% and fluorocarbon-modified acrylic leveling agent 0.7%, solvents being butyl acetate 3% and propylene glycol methyl ether acetate 3.3%, and drier 0.3%.

[0029] The curing agent comprises the following components in weight percentages: TDI trimer 10%, L-75 adduct 70%, and butyl acetate 20%.

[0030] The thinner comprises components in the following mass percentages: xylene 30%, propylene glycol methyl ether acetate 30%, and butyl acetate 40%.

[0031] The weight ratio of the main agent, curing agent, and thinner is 1:1:0.6.

[0032] Among them, the raw material models are as follows: the synthetic fatty acid alkyd resin is TIRES 2848YA resin; the modified acrylic resin is MFRC-5550YT; the polyaldehyde resin is 70% CR-2100 polyaldehyde resin; the defoamer is BYK141; the polyether-modified polymethylsiloxane leveling agent is BYK-333, and the fluorocarbon-modified acrylic leveling agent is EFKA3777N; the drier is T-12; the L-75 adduct is L-75E; there are no requirements for the models of butyl acetate, propylene glycol methyl ether acetate, TDI trimer, and xylene.

[0033] The preparation method is to mix the synthetic fatty acid alkyd resin, modified acrylic resin, and polyaldehyde resin and stir at a low speed. The low-speed stirring is at a rotation speed of 800 r / min for 8 minutes; then add the defoamer, leveling agent, solvent, and drier and stir at a high speed. The high-speed stirring is at a rotation speed of 1000 r / min for 12 minutes, and it is obtained after the mixing and stirring are completed.

[0034] Comparative Example 1 Compared with Example 1, the difference is only that the raw materials of the main agent are different, and the other raw materials and steps are the same as those in Example 1. The raw materials of the main agent are components in the following weight percentages: synthetic fatty acid alkyd resin 42%, high-hydroxyl acrylic resin 48%, defoamer 0.5%, leveling agent is polyether-modified polymethylsiloxane leveling agent 0.1% and fluorocarbon-modified acrylic leveling agent 0.2%, solvent is butyl acetate 5.1% and propylene glycol methyl ether acetate 4%, and drier 0.1%. Among them, the model of the high-hydroxyl acrylic resin is Changxing 7326-X-65 acrylic resin, and the models of the other raw materials are the same as those in Example 1.

[0035] Comparative Example 2 Compared with Example 1, the difference is only that the raw materials of the main agent are different, and the other raw materials and steps are the same as those in Example 1. The raw materials of the main agent are components in the following weight percentages: synthetic fatty acid alkyd resin 48%, coconut fatty acid resin 42%, defoamer 0.5%, leveling agent is polyether-modified polymethylsiloxane leveling agent 0.2% and fluorocarbon-modified acrylic leveling agent 0.8%, solvent is butyl acetate 3.5% and propylene glycol methyl ether acetate 4.6%, and drier 0.4%. Among them, the model of the coconut fatty acid resin is Changlong DG-3070-70CL, and the models of the other raw materials are the same as those in Example 1.

[0036] Comparative Example 3 Compared with Example 1, the difference lies only in the raw materials of the main agent, and the rest of the raw materials and steps are the same as those in Example 1. The raw materials of the main agent are components with the following weight percentages: 90% of synthetic fatty acid alkyd resin, 0.5% of defoamer, 0.2% of polyether-modified polymethylsiloxane leveling agent and 0.8% of fluorocarbon-modified acrylic leveling agent as the leveling agent, 3.5% of butyl acetate and 4.6% of propylene glycol methyl ether acetate as the solvent, and 0.4% of drier.

[0037] The bright finish topcoats prepared in Example 1 and Comparative Examples 1 to 3 were tested. The test methods refer to: viscosity GB / T 9751-1988, fineness GB / T 6753.1-2007, adhesion GB / T 9286-98, workability HG / T 3655-2012, item 5.4.7 and GB18581-2020, storage stability HG / T 3655-2012, item 5.4.4 and GB18581-2020. The model and proportion of the raw materials of the main agent are shown in Table 1, and the performance test results are shown in Table 2.

[0038] Table 1 Model and proportion of the raw materials of the main agent in Example 1 and Comparative Examples 1 to 3

[0039] Table 2 Performance test results of the bright finish topcoats prepared in Example 1 and Comparative Examples 1 to 3

[0040] Note: In the above workability and fullness tests, the optimal value is 5 digits, and the worst is 1.

[0041] Combining Table 1 and Table 2, it can be seen that the effect of preventing prickly heat in the thick coating of the bright finish topcoat prepared in Example 1 of the present invention is better than that of Comparative Examples 1 to 3, and the bright finish topcoat prepared by the technical solution provided by the present invention has excellent results in terms of hardness and thermal cycling test results, and is also better than the comparative examples in terms of workability tolerance and fullness.

[0042] Generally speaking, from the perspective of customers' batch use, considering workability tolerance, performance versatility and various on-site factors such as environment, temperature, and process, it can excellently solve the problem of prickly heat when using thick coatings in summer at high temperatures and the problems of slow drying and slow hardness increase in winter, and the inability to polish after 24 hours. The final hardness of the paint film is high.

[0043] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A PU high-hardness bright finish clear topcoat for musical instruments, characterized in that, It includes a main agent, a curing agent and a thinner. The main agent includes components in the following weight percentages: synthetic fatty acid alkyd resin 25 - 35%, modified acrylic resin 45 - 55%, polyaldehyde resin 8 - 12%, defoaming agent 0.4 - 0.6%, leveling agent 0.8 - 1.1%, solvent 6 - 9%, drier 0.3 - 0.5%.

2. The PU high-hardness bright clear topcoat for musical instruments according to claim 1, wherein The curing agent includes components in the following mass percentages: TDI trimer 10 - 15%, L - 75 adduct 60 - 70%, butyl acetate 20 - 30%.

3. The PU high-hardness bright finish paint for musical instruments according to claim 1, characterized in that, The thinner includes components in the following mass percentages: xylene 30 - 50%, propylene glycol methyl ether acetate 10 - 30%, butyl acetate 20 - 40%.

4. The PU high-hardness bright finish paint for musical instruments according to claim 1, characterized in that, The solvent is butyl acetate and propylene glycol methyl ether acetate.

5. The PU high-hardness bright finish paint for musical instruments according to claim 4, characterized in that, The solvent includes components in the following weight percentages: butyl acetate 3 - 4%, propylene glycol methyl ether acetate 3 - 5%.

6. The PU high-hardness bright finish paint for musical instruments according to claim 1, characterized in that, The leveling agent is a fluorocarbon - modified acrylic leveling agent and a polyether - modified polymethylsiloxane leveling agent.

7. The PU high-hardness bright finish paint for musical instruments according to claim 1, characterized in that The leveling agent includes components in the following weight percentages: fluorocarbon - modified acrylic leveling agent 0.7 - 0.9%, polyether - modified polymethylsiloxane leveling agent 0.1 - 0.2%.

8. A preparation method of a PU high-hardness bright finish paint for musical instruments as described in any one of claims 1-7, characterized in that, It includes the following steps: mixing the synthetic fatty acid alkyd resin, modified acrylic resin and polyaldehyde resin and stirring at a low speed, then adding the defoaming agent, leveling agent, solvent and drier and stirring at a high speed for mixing to obtain the product.

9. The preparation method of the high-hardness bright PU clear topcoat for musical instruments according to claim 8, characterized in that, The low - speed stirring is at a rotation speed of 600 - 800 r / min and a stirring time of 8 - 12 min; the high - speed stirring is at a rotation speed of 1000 - 1200 r / min and stirring for 8 - 12 min.

Images