Polyaspartic acid ester coating as well as preparation method and application thereof

Abstract

The invention provides a polyaspartic acid ester coating as well as a preparation method and application thereof. The polyaspartic acid ester coating comprises a component A and a component B, specifically, the component A is prepared from 60-80 parts of polyaspartic acid ester resin, 2-5 parts of pigment filler, 3-4 parts of wetting dispersant, 0.5-2 parts of defoaming agent, 5-8 parts of thixotropic agent, 0.5-1 part of coupling agent and 15-25 parts of solvent A; the component B is prepared from 16 to 30 parts of HDI tripolymer, 8 to 10 parts of curing agent, 3 to 4 parts of molecular sieve activation powder and 10 to 12 parts of solvent B. The mass ratio of the component A to the component B is (2-8): 1. According to the application method, the prepared component A and the prepared component B are put into a paint conveying system and can be directly sprayed on the surface of an engine through a GRACO 2KE two-component paint spraying system, and an extra drying process is not needed. The paint has the characteristics of high gloss, high color value, high corrosion resistance, high weather resistance, high heat resistance and the like, so that the energy consumption in the production process is reduced, and meanwhile, the performance of an engine coating can be comprehensively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyaspartic acid ester coatings, and in particular relates to a polyaspartic acid ester coating and a preparation method and application thereof. Background Art

[0002] Most of the existing paints in the engine industry use high-temperature paints. These paints require very high baking temperatures during the painting process, resulting in huge energy consumption. In recent years, my country has proposed important measures such as energy conservation and consumption reduction and environmental protection, and has also put forward corresponding requirements for automotive paints and coating processes. In response to the national call, some automotive paints currently use water-based methods. However, water-based paints not only require high-temperature baking, but also require pre-baking, which consumes more energy and pays high wastewater treatment costs. At the same time, the transformation of the automotive painting line requires a lot of money and time, which will cause great pressure on automobile manufacturers.

[0003] Therefore, if a new type of coating specifically for engines can be designed to replace traditional epoxy, acrylic, alkyd, polyurethane and other coatings; and through material design to achieve high solid and low viscosity, no drying, fast curing, energy saving and low carbon, low VOC emissions, shortened delivery cycle and other excellent properties, thereby solving the problems of traditional coatings requiring drying process, high energy consumption, high VOC emissions, and long production delivery cycle, it will be of great significance to technical personnel in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a polyaspartic acid ester coating. In terms of formula design, the main raw materials of the present invention are polyaspartic acid ester resin and HDI trimer, and a high molecular compound is generated through the special chemical structure and reaction mechanism of the two, so as to achieve a rapid film-forming effect; the obtained product has excellent properties such as high solid and low viscosity, no drying, fast curing, low VOC emission, and excellent medium resistance parameters.

[0005] Specifically, the secondary amine group in the polyaspartic acid ester resin reacts with the isocyanate group in the HDI trimer under a specific ratio to form a polyurea structure. This reaction speed is fast and can be quickly cured at room temperature, so no additional baking equipment is required. At the same time, the viscosity of the polyaspartic acid ester resin is low, which makes it have good fluidity during the construction process and easy to spray, and only one construction is required to achieve the required film thickness. Therefore, the present invention obtains a polyaspartic acid ester coating with excellent performance through raw material design and ratio.

[0006] To achieve the above object, the present invention provides a polyaspartic acid ester coating, comprising component A and component B;

[0007] Wherein, component A includes: polyaspartic acid ester resin, pigments and fillers, additives and solvent A;

[0008] Component B includes: HDI trimer, curing agent, molecular sieve activation powder and solvent B.

[0009] In a preferred embodiment, the mass ratio of component A to component B is (2-8):1, and more preferably, the mass ratio of component A to component B is 5.5:1.

[0010] In a preferred embodiment, the component A specifically comprises the following components in parts by weight:

[0011] 60-80 parts of polyaspartic acid ester resin, 2-5 parts of pigments and fillers, 9-15 parts of additives, and 15-25 parts of solvent A.

[0012] In a preferred embodiment, the polyaspartic acid ester resin includes F520 resin and / or F524 resin; preferably, the polyaspartic acid ester resin is composed of F520 resin and F524 resin in a mass ratio of 1:1;

[0013] The pigments and fillers include rutile titanium dioxide and / or carbon black;

[0014] The auxiliary agent includes one or more of a wetting and dispersing agent, a defoaming agent, a thixotropic agent, and a coupling agent;

[0015] The solvent A includes butyl acetate.

[0016] In the present invention, the F520 resin is a traditional polyaspartic acid ester resin, which is characterized by good compatibility, a transparent and plump coating appearance, and a long construction activation period. Since the -NH group in the F520 molecular structure is a crown side chain alkyl group, and the steric hindrance effect of the methyl group on its adjacent cycloalkane chain hinders the free rotation of the molecular chain formed after the -NHR group and the isocyanate -NCO group react to form a film, resulting in a high glass transition temperature (Tg) of the coating and poor impact resistance. The present invention has found in experiments that the coating made with the HDI trimer begins to become brittle below 10°C and loses all adhesion to the substrate. Therefore, its performance must be modified. The basic performance of the F524 resin is similar to that of F420, except that when reacting with the HDI trimer curing agent, the gel time is more than 50 minutes. And the compatibility with silicone additives is much better than F420, and the appearance of the coating is greatly improved. When F524 and F520 resins are used in a mass ratio of 1:1 as a high-solid, low-viscosity coating, their optimal performance can be brought into play. Their construction activation period is 2 to 3 hours, and the coating surface drying time is less than 1 hour, which solves the construction difficulties of polyaspartic acid ester coatings.

[0017] In the present invention, both the rutile titanium dioxide and carbon black can be used as coloring pigments and fillers. Among them, rutile titanium dioxide plays a role in showing color and giving hiding power to the coating film due to its high refractive index, strong hiding power and high brightness, and can improve the weather resistance, wear resistance, glossiness, chemical resistance, etc. of the coating film. Carbon black has a small particle size, good hiding power and tinting power, excellent heat resistance and chemical resistance, and the gray coating prepared has strong hiding power, excellent weather resistance and water resistance.

[0018] In the present invention, the butyl acetate is an organic solvent, which is usually used as a solvent for producing varnish and other products. It is a colorless, flammable liquid with a sweet smell of banana or apple. In coatings, it helps to improve the smoothness and durability of the coating.

[0019] In a preferred embodiment, the component A specifically comprises the following components in parts by weight:

[0020] 60-80 parts of polyaspartic acid ester resin, 2-5 parts of pigments and fillers, 3-4 parts of wetting and dispersing agents, 0.5-2 parts of defoaming agents, 5-8 parts of thixotropic agents, 0.5-1 parts of coupling agents, and 15-25 parts of solvent A.

[0021] In a preferred embodiment, the wetting and dispersing agent includes Digo 628; the defoaming agent includes EFKA2722, the thixotropic agent includes R972; and the coupling agent includes KH560.

[0022] In the present invention, the Digo 628 is a wetting and dispersing agent used for wetting and dispersing medium and high polar solvents. It has an excellent viscosity reduction effect when used for dispersing inorganic pigments and fillers. The EFKA 2722 is a defoamer designed for solvent-free epoxy resins and polyurethane compounds. It can quickly eliminate bubbles, and when used as a leveling agent, it can make the coating surface very smooth. In addition, the product can also produce self-leveling coatings without foam and blisters. The R972 is a fumed silica that is post-treated with dimethyldichlorosilane (DDS) and is easy to disperse and suitable for a variety of applications. It has good dispersibility and can provide anti-settling, anti-sagging, anti-corrosion and other effects. The KH560 is an epoxy-containing coupling agent used for polysulfide and polyurethane caulking glue and sealant, epoxy resin adhesive, filled or reinforced thermosetting resin, glass fiber adhesive and inorganic filled or glass reinforced thermoplastic resin, etc.

[0023] In a preferred embodiment, the B component specifically includes the following components by weight:

[0024] 16-30 parts of HDI trimer, 8-10 parts of curing agent, 3-4 parts of molecular sieve activation powder and 10-12 parts of solvent B.

[0025] In a preferred embodiment, the HDI trimer is HI 190B / S;

[0026] The curing agent is SP-103P curing agent;

[0027] The molecular sieve activation powder is 4A molecular sieve activation powder;

[0028] The solvent B includes butyl acetate.

[0029] In the present invention, the 190B / S is a HDI trimer used as a curing agent. It reacts with polyaspartic acid resin to form a hard coating. Due to the high solid and thick coating characteristics of polyaspartic acid polyurea coatings, the paint film has a certain shrinkage during the curing process and causes stress concentration. Therefore, in the present invention, a highly weather-resistant elastic curing agent SP-103P is added to improve the flexibility of the coating. SP-103P is a highly weather-resistant elastic curing agent used to improve the flexibility of the coating. It can provide better coating performance when used in combination with 190B / S, especially under dynamic conditions, such as temperature changes or mechanical stress.

[0030] Molecular sieve activated powder is made by high-temperature calcination of molecular sieve raw powder, and has good dispersibility and fast adsorption speed. Molecular sieve activated powder is added to the curing agent component to reduce the impact of moisture and low molecular alcohol. Molecular sieve activated powder has strong activity and can be directly used as a selective adsorbent in coating production. It has the effect of reducing moisture, eliminating bubbles, and improving material uniformity and strength without changing the physical and chemical properties of the coating itself.

[0031] The role of butyl acetate in component B is to act as a solvent to help adjust the viscosity and fluidity of the coating for ease of construction and film formation. It also helps to improve the solubility and mixing properties of the coating, ensuring that the coating components are evenly mixed.

[0032] Another object of the present invention is to provide a method for preparing a polyaspartic acid ester coating, which specifically comprises the following steps:

[0033] Preparation of component A:

[0034] (1) Weigh the raw materials by weight;

[0035] (2) Add polyaspartic acid ester resin to solvent A and stir and disperse at 300-400 rpm until transparent;

[0036] (3) Add wetting and dispersing agent, defoaming agent, thixotropic agent and pigments and fillers in sequence, and stir at a high speed of 600-800 rpm until dispersed;

[0037] (4) Add coupling agent and disperse evenly, grind to a fineness of less than 30 μm;

[0038] Preparation of component B:

[0039] (1) Weigh the raw materials by weight;

[0040] (2) Add the molecular sieve activated powder into solvent B and stir at 300-400 rpm until dispersed;

[0041] (3) Add HDI trimer and curing agent and stir evenly at a high speed of 600-800 rpm to obtain the product.

[0042] Another object of the present invention is to provide an application of a polyaspartic acid ester coating in the field of engine coatings. The component A and component B prepared by the present invention are respectively put into the paint delivery system, and the GRACO 2KE two-component coating spraying system can be directly sprayed on the engine surface without the need for an additional drying process. After spraying, it only needs to dry for 1-2 hours at room temperature before packaging and delivery. Moreover, since the coating obtained by the present invention has the characteristics of high gloss, high appearance, high corrosion resistance, high weather resistance, and high heat resistance, it can reduce energy consumption in the production process while also comprehensively improving the performance of the engine coating.

[0043] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0044] 1. High-solid, low-viscosity technology: The present invention adopts high-solid, low-viscosity polyaspartic acid ester coating, whose solid content is more than 85%, and the viscosity of four cups of coating is between 40-80 seconds, ensuring excellent covering power and construction fluency, while greatly reducing the use of solvents. Conventional air spraying can be used, and the construction is convenient and low-cost, and it can be constructed without large equipment investment of airless spraying or mixed air spraying.

[0045] 2. Drying-free energy-saving technology: The unique formula design of the present invention enables the coating to cure quickly without drying after application, significantly saving energy and time and improving production efficiency. The drying energy consumption is saved by 100% and the production efficiency is increased by 50%. This is an advantage that traditional coatings cannot match and is in line with the concept of green production.

[0046] 3. Rapid curing technology: The efficient curing system of the present invention ensures that the coating can reach the required strength and hardness in a very short time. The surface drying time is about 30 minutes at room temperature, the drying and hardening time is about 60 minutes, and adhesion can be established in 5 hours (traditional paints generally take more than 48 hours), which is more than 8 times shorter than the drying and curing time of traditional coatings.

[0047] 4. Low VOC emission: The coating formula provided by the present invention has the advantages of high solid and low viscosity, and the construction VOC is about 100-200g / L, which is similar to water-based paint. Compared with traditional solvent-based products, VOC emission reduction is more than 60%. It ensures that the VOC emission of the coating is extremely low during use, which is significantly better than traditional coatings in terms of protecting the environment and the health of operators.

[0048] 5. Shorten the delivery cycle: The use of the coating provided by the present invention can shorten the delivery cycle by more than 50%. The characteristics of no drying and fast curing enable the coating to quickly form a protective layer after application, significantly shortening the production and delivery cycle of the engine. The engine can be offline 1.5 hours after spraying at room temperature. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with specific implementation methods, but it should be understood that the protection scope of the present invention is not limited by the specific implementation methods.

[0050] The technical solution of the present application is described in detail below through specific embodiments:

[0051] Unless otherwise specified, the technical means used in the present invention are conventional means well known to those skilled in the art, and the various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods. The reagents used in the present invention are analytically pure unless otherwise specified.

[0052] In the present invention, parts by weight may be μg, mg, g, kg or other weight units known in the art, or multiples thereof, such as 1 / 10, 1 / 100, 10 times, 100 times or the like.

[0053] Example 1

[0054] A polyaspartic acid ester coating, the formula of which is:

[0055] Component A: 68 parts of polyaspartic acid ester resin (F524 resin and F520 resin mixed in a mass ratio of 1:1), 3.4 parts of pigment (carbon black), 4 parts of wetting and dispersing agent (Digo 628), 2 parts of defoaming agent (EFKA 2722), 6 parts of thixotropic agent (R972), 1.5 parts of coupling agent (KH560), and 25 parts of solvent A (butyl acetate).

[0056] Component B: 28 parts of HDI trimer (HI 190B / S), 10 parts of curing agent (SP-103P), 3 parts of molecular sieve activation powder (4A molecular sieve activation powder) and 12 parts of solvent B (butyl acetate).

[0057] Its preparation method is:

[0058] Preparation of component A:

[0059] (1) Weigh the raw materials by weight;

[0060] (2) Add polyaspartic acid ester resin to solvent A and stir and disperse at 400 rpm until transparent;

[0061] (3) Add wetting and dispersing agent, defoaming agent, thixotropic agent and pigments and fillers in sequence, and stir at 600 rpm until dispersed;

[0062] (4) Add coupling agent and disperse evenly, grind to a fineness of less than 30 μm;

[0063] Preparation of component B:

[0064] (1) Weigh the raw materials by weight;

[0065] (2) Add the molecular sieve activated powder into solvent B and stir at 300 rpm until dispersed;

[0066] (3) Add HDI trimer and curing agent and stir evenly at 800 rpm.

[0067] Its application method is:

[0068] The prepared component A and component B are respectively put into the paint delivery system at a mass ratio of 5.5:1, and are directly sprayed on the engine surface using the GRACO2KE two-component paint spray system. After spraying, they only need to dry at room temperature for 1 hour.

[0069] Effect example

[0070] The performance data of the coating prepared in Test Example 1 and the coating obtained after spraying on the engine are shown in Tables 1-3.

[0071] Table 1 Engine topcoat parameters

[0072] Test items Detection indicators Test results Detection Methods 1. Original paint status Uniform without impurities qualified Visual inspection 2. Fineness, ym 15 10 GB / T1724-1979 3. Viscosity (Tu-4), s 40-60 49.8 GB / T1723-1993 4. Specific gravity, g / ml 1.20+0.05 1.22 GB / T6750-2007 5. Solid content, % 75 88.5 GB / T1725-2007 6. Construction solid content, % 70 70.2 GB / T1725-2007 7. Sagging, μm 50 55 GB / T9264-2012 8. Resistance value, MO 0.5-2.0 0.85 Resistance meter

[0073] Table 2 Physical parameters of engine paint coating

[0074]

[0075]

[0076] Table 3 Paint coating medium resistance parameters

[0077]

[0078]

[0079] In summary, the application of the polyaspartic acid coating provided by the present invention on the engine demonstrates the excellent performance and multiple advantages of the new coating. It has the remarkable characteristics of high solid and low viscosity, no drying, fast curing, energy saving, low VOC emissions, and shortened delivery cycle, making it possible for the coating to provide engine manufacturers and end users with a more high-quality, efficient, and environmentally friendly coating solution. In the future, with the continuous maturity of technology and the expansion of the market, polyaspartic acid coatings are expected to be widely used in the engine field and more related fields, contributing to the development of industrial coating technology and the advancement of environmental protection.

[0080] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A polyaspartic acid ester coating, characterized in that: It includes component A and component B; Wherein, component A includes: polyaspartic acid ester resin, pigments and fillers, additives and solvent A; Component B includes: HDI trimer, curing agent, molecular sieve activation powder and solvent B.

2. The polyaspartic acid ester coating according to claim 1, characterized in that: The mass ratio of component A to component B is (2-8):

1.

3. The polyaspartic acid ester coating according to claim 1, characterized in that: The component A specifically comprises the following components by weight: 60-80 parts of polyaspartic acid ester resin, 2-5 parts of pigments and fillers, 9-15 parts of additives, and 15-25 parts of solvent A.

4. The polyaspartic acid ester coating according to claim 3, characterized in that: The polyaspartic acid ester resin includes F520 resin and / or F524 resin; the pigment and filler include rutile titanium dioxide and / or carbon black; the auxiliary agent includes one or more of a wetting dispersant, a defoaming agent, a thixotropic agent, and a coupling agent; and the solvent A includes butyl acetate.

5. The polyaspartic acid ester coating according to claim 4, characterized in that: The component A specifically comprises the following components by weight: 60-80 parts of polyaspartic acid ester resin, 2-5 parts of pigments and fillers, 3-4 parts of wetting and dispersing agents, 0.5-2 parts of defoaming agents, 5-8 parts of thixotropic agents, 0.5-1 parts of coupling agents, and 15-25 parts of solvent A.

6. The polyaspartic acid ester coating according to claim 5, characterized in that: The wetting and dispersing agent includes Digo 628; the defoaming agent includes EFKA 2722, the thixotropic agent includes R972; and the coupling agent includes KH560.

7. The polyaspartic acid ester coating according to claim 1, characterized in that: The B component specifically includes the following components by weight: 16-30 parts of HDI trimer, 8-10 parts of curing agent, 3-4 parts of molecular sieve activation powder and 10-12 parts of solvent B.

8. The polyaspartic acid ester coating according to claim 7, characterized in that: The HDI trimer is HI 190B / S; the curing agent is SP-103P curing agent; the molecular sieve activation powder is 4A molecular sieve activation powder; and the solvent B includes butyl acetate.

9. The method for preparing the polyaspartic acid ester coating according to any one of claims 1 to 8, characterized in that: The following steps are involved: Preparation of component A: (1) Weigh the raw materials by weight; (2) Add polyaspartic acid ester resin to solvent A and stir and disperse at 300-400 rpm until transparent; (3) Add wetting dispersant, defoamer, thixotropic agent and pigments and fillers in sequence, and stir at a high speed of 600-800 rpm until dispersed; (4) Add the coupling agent and disperse evenly, and grind to a fineness of less than 30 μm; Preparation of component B: (1) Weigh the raw materials by weight; (2) Add the molecular sieve activated powder into solvent B and stir at 300-400 rpm until dispersed; (3) Add HDI trimer and curing agent and stir evenly at a high speed of 600-800 rpm to obtain the product.

10. The method for applying the polyaspartic acid ester coating according to any one of claims 1 to 8, characterized in that: Put component A and component B into the paint delivery system respectively. After being evenly mixed by the static mixer of the GRACO 2KE two-component spraying equipment, they can reach the spray gun for spraying.

Images