A bio-based automotive exterior paint and its preparation method and application method

Abstract

The present invention provides a bio-based automotive exterior paint, as well as a preparation method and an application method thereof. The present invention prepares a coating suitable for automotive exterior by using three bio-based resins, a bio-based solvent, a bio-based curing agent, a metallic color paste and other components. The coating has a high biomass content, which accounts for more than 85%, and has excellent performance.

Description

Technical Field

[0001] The invention relates to the field of bio-based materials, and in particular to a bio-based automobile exterior paint and a preparation method and an application method thereof. Background Art

[0002] The world's main energy source today is fossil energy, but with the increase in usage, fossil energy is decreasing, and related products and enterprises based on fossil energy are subject to great restrictions. At the same time, as the government has long attached great importance to green environmental protection, the rapid development of bio-based materials based on renewable resources has become an inevitable trend under the policy background of green, healthy and environmental protection.

[0003] In the field of coatings, although some bio-based materials are used in coating systems, they are not widely used due to their poor performance and relatively high prices. Moreover, in most other bio-based coatings on the market, although they are called bio-based coatings, the biomass content is not high. The reason is: compared with resins prepared from fossil energy, bio-based resins have many different structures. Therefore, the prepared bio-based coatings have poor stability, which also leads to the fact that the biomass content in the coating should not be too high.

[0004] The application of bio-based materials in automotive coatings is even rarer. Due to the need to control the color of the car body, metallic color pastes need to be added to the coatings. However, there are some problems with the use of color pastes and bio-based materials together: bio-based resins have low compatibility with metallic color pastes, and it is relatively difficult to select suitable resins; using metallic color pastes to replace electroplating of automotive exterior parts has certain challenges in terms of adhesion and gloss. Summary of the invention

[0005] In order to solve the problems existing in the above background technology, the purpose of the present invention is to provide a bio-based automotive exterior paint, as well as a preparation method and application method thereof. The present invention prepares a coating suitable for automotive exterior by using three bio-based resins, a bio-based solvent, a bio-based curing agent, a metallic color paste and other components, and has a high biomass content and excellent performance.

[0006] In the current paint production or application companies, the bio-based materials used are relatively single, and excellent performance cannot be guaranteed. Although there are certain innovations and environmental protection features, the scale is not large. The main purposes of this invention are as follows:

[0007] (1) Through in-depth understanding of the characteristics of bio-based resins, we seek the most suitable metallic color paste so that the metallic texture and performance of the subsequent paint film can meet customer requirements. In the subsequent cooperation process, it can replace the electroplating of automotive exterior parts.

[0008] (2) In the process of preparing the coating, adding an appropriate amount of bio-based solvent not only increases the overall biomass content of the coating, but also can well disperse the bio-based resin and color paste to ensure the stability between them.

[0009] (3) The coating is prepared as a two-component coating and a bio-based curing agent is used to give it good comprehensive performance.

[0010] (4) Expand subsequent application areas through understanding of bio-based resins, bio-based solvents and bio-based curing agents.

[0011] Specifically, the present invention first provides a bio-based automotive exterior paint, including component A and component B;

[0012] The A component includes the following raw materials in parts by weight:

[0013]

[0014] The B component includes the following raw materials in parts by weight:

[0015] 35-45 parts of bio-based curing agent

[0016] Preferably,

[0017] The A component includes the following raw materials in parts by weight:

[0018]

[0019]

[0020] The B component includes the following raw materials in parts by weight:

[0021] 39 parts of bio-based curing agent

[0022] in:

[0023] The bio-based fatty acid polyester has a bio-based raw material content of 80-100%, a functionality of 2.6, a hydroxyl value (based on solid content) of 240 mgKOH / g, and a viscosity of 850 mPa·s at 25°C.

[0024] The cellulose ester has a hydroxyl content of 1.5 wt %, a Tg of 130° C., and a number average molecular weight of 30,000.

[0025] The bio-based aliphatic polyol has a bio-based raw material content of 80-100%, a functionality of 2.5, a hydroxyl value (based on solid content) of 270 mgKOH / g, and a viscosity of 530 mPa·s at 20°C.

[0026] The bio-based solvent is butyl lactate, which has a molecular weight of 146 and can dissolve natural resins and synthetic resins, etc. Bio-based butyl lactate can not only dissolve resins and cellulose, but also increase the biomass content in the entire product formulation system.

[0027] The thixotropic additive is an AEROSIL series product, which has good hydrophobicity and can improve the anti-sagging performance of the paint and has little effect on leveling.

[0028] The leveling agent is a modified polydimethylsiloxane leveling agent, which can improve the leveling property of the paint and improve defects such as shrinkage holes in the paint film.

[0029] The metal color paste is a high-brightness PVD-aluminum pigment color paste with good stability.

[0030] The bio-based curing agent is a new type of isocyanate curing agent, with a bio-based content of more than 50%, a viscosity of 13000 mPa·s at 25°C, and an NCO content of 22.8%. The bio-based aliphatic isocyanate not only has good low-temperature curing performance, but also improves the chemical resistance and solvent resistance of the product. Due to its high bio-based content, it contributes to green environmental protection and the use of sustainable resources.

[0031] Among the above bio-based materials, bio-based fatty acid polyester resin has good bonding and self-leveling properties due to its low viscosity and strong hydrophobicity. Cellulose ester and polyester resin not only have good chemical resistance and compatibility, but also provide stable color tone and excellent color development in pigment dispersion. Bio-based aliphatic polyol has good bonding properties and also has the effect of improving hardness.

[0032] In the above-mentioned coating preparation process, resin is the main film-forming substance in the coating and also the provider of various basic properties. Understanding the characteristics of bio-based resin is the prerequisite for preparing excellent performance coatings. Although the amount of additives added is small, they play a key role in improving and improving the performance of coatings and coatings. In addition, the use of metallic color paste can replace the electroplating of automotive exterior parts. Through the overall understanding of bio-based raw materials, two-component coatings are prepared to achieve the purpose of the present invention.

[0033] The present invention also provides a method for preparing the above-mentioned bio-based automobile exterior paint, comprising the following steps:

[0034] (1) Component A: Add bio-based fatty acid polyester, cellulose ester, bio-based aliphatic polyol, bio-based solvent, color paste, thixotropic additive and leveling agent into a paint bucket according to a certain mass ratio, and use a high-speed disperser to fully mix them at a speed of 800 r / min for 25 min;

[0035] (2) Component B: Component B is a bio-based curing agent, a novel isocyanate. If the viscosity is high, it can be appropriately diluted with the bio-based solvent butyl lactate.

[0036] The present invention also provides an application method of the above-mentioned bio-based automobile exterior paint, comprising the following steps:

[0037] (1) Weigh a certain amount of component A in a paint mixing bucket, and then mix component B according to the total hydroxyl content of the resin added to component A. Through calculation and previous experience, it is concluded that the mass ratio of component A to component B is 1.8:1;

[0038] (2) Mix the above components and stir them evenly, then spray them with a hand spray gun. The spray film thickness is controlled at 5-10 μm.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The present invention mainly prepares a bio-based paint coating that can be used for automobile exterior decoration through the understanding of bio-based materials. Bio-based raw materials are used to replace most of the fossil raw materials in traditional solvent-based paints, so that they have a high biomass content, which contributes to the environment and sustainable development. The biomass content of the paint provided by the present invention is as high as 85% or more.

[0041] (2) The components are designed based on the characteristics of bio-based materials, so that each system has good stability in high-biomass coatings and has excellent performance based on high biomass content, which improves the application field of bio-based coatings.

[0042] (3) Test and select suitable metallic color pastes, and prepare bio-based paints with metallic texture by combining bio-based resins with metallic color pastes. Such paints can be applied to automotive exterior coatings and are expected to replace some automotive exterior electroplating products in the future.

[0043] (4) Through experiments and subsequent performance tests, the automotive exterior paint prepared by the present invention has met customer needs and has excellent performance. DETAILED DESCRIPTION

[0044] Examples 1-6

[0045] 1. Paint raw materials:

[0046] Bio-based fatty acid polyester (resin A): bio-based fatty acid polyester produced by BASF;

[0047] Cellulose ester (resin B): butyl acetate cellulose produced by Eastman Company;

[0048] Bio-based aliphatic polyol (resin C): bio-based aliphatic polyol produced by BASF;

[0049] Bio-based solvent: Bio-based butyl lactate produced by GALACTIC;

[0050] Color paste: High brightness aluminum pigment color paste (HYDROSHINE WS 3003) produced by ALTANA;

[0051] Thixotropic additive: EVONIK's AEROSIL series (AEROSIL R-972);

[0052] Leveling agent: modified polydimethylsiloxane (BYK331) produced by BYK;

[0053] Bio-based curing agent: A new bio-based isocyanate (D-3725N) produced by Mitsui Chemicals.

[0054] 2. Raw material ratio: The raw material ratio of Example 1-6 and Comparative Example 1-2 is shown in Table 1-1 and Table 1-2 respectively.

[0055] Table 1-1 Example Raw Material Ratio

[0056]

[0057] Table 1-2 Comparative Example Raw Material Ratio

[0058]

[0059]

[0060] Wherein, petroleum resin A is hydroxy acrylic resin, with a solid content of 70%, a viscosity of 3000-6000 mPa·s at 25°C, and a hydroxyl value (solution) of 110 mgKOH / g; petroleum resin B is hydroxy acrylic resin, with a solid content of 70%, a hydroxyl value (solution) of 70 mgKOH / g; petroleum resin C is hyperbranched polyester polyol, with a solid content of 70%, a viscosity of 4000 mPa·s at 25°C, and a hydroxyl value (based on solid) of 270 mgKOH / g; petroleum solvent is butyl acetate; petroleum curing agent is a conventional polyisocyanate curing agent, HDI trimer, with a solid content of 100%, and an NCO content of 22%. Color paste, thixotropic additive and leveling agent are the same as those in the embodiment.

[0061] 3. Paint preparation process

[0062] (1) Component A: Add bio-based fatty acid polyester, cellulose ester, bio-based aliphatic polyol, bio-based solvent, color paste, thixotropic additive and leveling agent into a paint bucket according to a certain mass ratio, and use a high-speed disperser to fully mix them at a speed of 800 r / min for 25 min;

[0063] (2) Component B: Component B is a bio-based curing agent, a novel isocyanate. If the viscosity is high, it can be appropriately diluted with the bio-based solvent butyl lactate.

[0064] 4. Paint application process

[0065] (1) Weigh component A and component B respectively according to the mass ratio of component A to component B being 1.8:1;

[0066] (2) Mix the above-mentioned component A and component B and stir them thoroughly, then spray them with a hand spray gun, and the spray film thickness is controlled to be 5-10 μm.

[0067] 5. Paint testing process

[0068] Adhesion test: Perform the paint film adhesion test according to GB / T 9286-1998. Use a cross-scratcher to make 100 squares on the surface of the cured and dried paint film, then use 3M tape to stick the 100 squares to make full contact, then quickly pull off the tape and use a magnifying glass to observe the peeling of the paint film at the 100 squares.

[0069] Gloss (60°) test: Test according to GB / T 9754-2007. Prepare the paint film according to the plate making method in 2.6.1, and then test with a gloss tester (60°). The average value of three tests is the gloss of the paint film.

[0070] Condensation test: According to ISO 6270-2, the condensation test is carried out. The cured and dried paint film sample is placed in the test box (temperature is 40°C, humidity is 100%) in the prescribed manner, and then tested for 10 days, after which the degree of bubbles on the paint film surface is observed.

[0071] Hydrolysis test: Hydrolysis test is carried out according to Volkswagen automotive trim test standard TL226. The cured and dried paint film sample is placed in a climate chamber at (90±2)℃ and (95±1)% relative humidity in a prescribed manner, and the paint film performance is evaluated after 72 hours.

[0072] High-pressure water impact test: According to ISO 16925-2014, high-pressure water impact test is carried out. Before the test, the substrate is scratched through the prepared sample surface with a scratch tester (one side>12cm, one side>5cm, angle 30°), and the angle is aligned with the high-pressure nozzle, with a distance of 100±1mm. Use a high-pressure water impact instrument to spray (water temperature 60±2℃, nozzle angle 90±2°, water flow pressure 68-70Bar) for 1 minute and then evaluate according to the state of the paint film.

[0073] Hot and cold alternating test: According to the PV2005 automotive parts climate alternating stability test, the prepared test specimens are placed in a climate chamber with a certain program (low temperature -40°C, high temperature 80°C) for cycle testing, and performance evaluation is carried out after the required number of tests.

[0074] 6. Test Results

[0075] The test results are shown in Table 2:

[0076] Table 2 Test results

[0077]

[0078] The test results show that the automotive exterior paints made with bio-based resins, bio-based solvents and bio-based curing agents have excellent performance, and compared with petroleum-based automotive exterior paints, the adhesion, gloss and other properties can reach the performance of petroleum-based paint films. Condensation water test, hydrolysis test, high-pressure water impact test and hot and cold alternating test can meet the application performance requirements, and can well replace some petroleum-based automotive exterior paint products, thereby reducing the pollution of solvent-based coatings to the environment and the harm to human health.

Claims

1. A bio-based automotive exterior paint, characterized in that: It includes component A and component B; The A component includes the following raw materials in parts by weight: The B component includes the following raw materials in parts by weight: 35-45 parts of bio-based curing agent The bio-based fatty acid polyester has a bio-based raw material content of 80-100%, a functionality of 2.6, a hydroxyl value of 240 mgKOH / g based on solid content, and a viscosity of 850 mPa·s at 25°C; The bio-based aliphatic polyol has a bio-based raw material content of 80-100%, a functionality of 2.5, a hydroxyl value of 270 mgKOH / g based on solid content, and a viscosity of 530 mPa·s at 20° C.; The color paste is a high-brightness PVD-aluminum pigment color paste with good stability; The cellulose ester has a hydroxyl content of 1.5 wt %, a Tg of 130° C., and a number average molecular weight of 30,000; The leveling agent is a modified polydimethylsiloxane leveling agent; The bio-based solvent is butyl lactate, which has a molecular weight of 146; The bio-based curing agent is a new type of isocyanate curing agent, the bio-based content of which exceeds 50%, the viscosity of which is 13000 mPa·s at 25° C., and the NCO content of which is 22.8%.

2. The bio-based automotive exterior paint according to claim 1, characterized in that: The A component includes the following raw materials in parts by weight: The B component includes the following raw materials in parts by weight: 39 parts of bio-based curing agent.

3. The bio-based automotive exterior paint according to claim 1, characterized in that: The thixotropic agent is AEROSIL R-972.

4. A method for preparing a bio-based automotive exterior paint according to claim 1, characterized in that: The following steps are involved: (1) Component A: Add bio-based fatty acid polyester, cellulose ester, bio-based aliphatic polyol, bio-based solvent, color paste, thixotropic additive and leveling agent into a paint bucket according to a certain mass ratio, and use a high-speed disperser to fully mix them at a speed of 800 r / min for 25 min; (2) Component B: Component B is a bio-based curing agent. If the viscosity is high, it can be appropriately diluted with the bio-based solvent butyl lactate.

5. A method for applying the bio-based automotive exterior paint according to claim 1, characterized in that: The following steps are involved: (1) Weigh component A and component B respectively according to the mass ratio of component A to component B being 1.8:1; (2) Mix the above-mentioned component A and component B and stir them thoroughly, then spray them with a hand spray gun, and the spray film thickness is controlled to be 5-10 μm.

Images