Basecoat for aircraft skin and method for producing the same

Abstract

The application provides a base color paint for aircraft skin and a preparation method thereof. The base color paint for aircraft skin provided by the application is composed of base component A, curing agent component B and diluent component C, the components of the base component A and the weight part of each component are as follows: polyester resin 10-25 parts, toughening resin 1-5 parts, titanium white powder 48-65 parts, silicon dioxide 0.1-1 part, anti-sagging agent 1-3 parts, wetting dispersant 1-5 parts, drier 0.01-1 part, leveling agent 0.01-1 part, dimethylbenzene 5-15 parts, butyl acetate 5-10 parts, propylene glycol methyl ether acetate 1-5 parts, the mass ratio of the base component A, the curing agent component B and the diluent component C is 10:2:(1.5-2.5), the base color paint has the properties of high solid content, strong hiding power, good medium resistance, excellent color and gloss retention, and is suitable for being matched with varnish for aircraft skin, the material properties and on-site coating performance of the paint meet the use requirements of users.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating chemical industry, in particular, relates to a base color paint for aircraft skin and a preparation method thereof. BACKGROUND

[0002] At present, the main aircraft skin coating systems in China are: two-component acrylic polyurethane system, two-component polyester polyurethane system, two-component fluorine-containing polyurethane system, and two-component silicon-containing polyurethane system. Although the above-mentioned aircraft skin coating systems have the advantages of good comprehensive performance and high cost performance, they have poor color and gloss retention, high VOC content, do not meet the environmental protection trend, and have lower hiding power than the base color paint for aircraft skin under the same film thickness, which cannot achieve the effect of reducing the weight of the aircraft. With the new production of Airbus and Boeing aircraft gradually using BC / CC (BASE COAT / CLEAR COAT) coating system (base color paint / clear paint system) products to replace the conventional coating system products, the domestic large commercial aircraft C-919, the domestic large fire extinguishing / water rescue amphibious aircraft AG600, the civil medium-sized aircraft MA600, MA700, and LE-500, LE-700, and other small aircraft have also included the BC / CC coating system into the type design specification, so that the BC / CC coating system will gradually become the mainstream product for civil aircraft painting. Therefore, it is urgent to design a base color paint with high solid content, strong hiding power, good medium resistance, excellent color and gloss retention, which is suitable for being used with the clear paint for aircraft skin, so that the material properties and on-site coating performance of the coating meet the user's requirements. SUMMARY

[0003] The purpose of the embodiment of the present application is to provide a base color paint for aircraft skin, so as to solve the technical problems of the existing coating system for aircraft skin, such as low solid content, poor color and gloss retention, weak hiding power, and high VOC content which does not meet the environmental protection requirements.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application is to provide a base color paint for aircraft skin, which comprises a base component A, a curing agent component B, and a diluent component C, wherein the base component A comprises the following components in the following mass fractions:

[0005]

[0006] The mass ratio of the base component A, the curing agent component B, and the diluent component C is 10:2:(1.5-2.5).

[0007] Optionally, the curing agent component B comprises aliphatic isocyanate polymer 60-75 parts, butyl acetate 15-25 parts, and propylene glycol methyl ether acetate 5-15 parts in terms of mass fraction.

[0008] Optionally, the aliphatic isocyanate polymer is at least one of hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer.

[0009] Optionally, the diluent component C includes xylene 40-55 parts by mass, diheptanone 15-35 parts by mass, propylene glycol methyl ether acetate 10-25 parts by mass, cyclohexanone 5-15 parts by mass, and divalent acid ester 1-5 parts by mass.

[0010] Optionally, the wet dispersant is at least one of a copolymer solution having an acidic group, a modified polyurethane type high molecular dispersant, and a high molecular weight block copolymer solution containing a pigment affinity group.

[0011] Optionally, the polyester resin has a hydroxyl content of 6.5-8.5%, a solid content of 68-72%, and a viscosity of 4000-10000 mPa·s.

[0012] Optionally, the toughening resin is a slightly branched flexible polyester polyol resin having a hydroxyl value of 120-180 mgKOH / g.

[0013] Another object of the embodiment of the present application is to provide a preparation method of a base color paint for an aircraft skin, so as to solve the technical problems of low solid content, poor color and gloss retention, weak hiding power, and high VOC content of the existing coating system for the aircraft skin, which do not meet the environmental protection requirements.

[0014] To achieve the above object, the technical scheme adopted by the present application is to provide a preparation method of a base color paint for an aircraft skin, which comprises the following steps:

[0015] Preparation of base component A: add polyester resin 10-25 parts, toughening resin 1-5 parts, titanium dioxide 48-65 parts, silicon dioxide 0.1-1 parts, anti-sagging agent 1-3 parts, wet dispersant 1-5 parts, drier 0.01-1 parts, leveling agent 0.01-1 parts, xylene 5-15 parts, butyl acetate 5-10 parts, propylene glycol methyl ether acetate 1-5 parts, and solvent into a cylinder in sequence, and disperse the mixture by using a high-speed disperser to obtain a mixed base; grind the mixed base into a slurry with a fineness of ≤12.5 μm, and filter the slurry through a 120-200 mesh filter screen after being dispersed by using a high-speed disperser, so as to prepare the base component A.

[0016] Preparation of curing agent component B: add aliphatic isocyanate polymer 60-75 parts, butyl acetate 15-25 parts and propylene glycol methyl ether acetate 5-15 parts into a cylinder in sequence, and then disperse them by using a high-speed disperser, and filter them through a filter screen with a mesh size of 120-200, so that curing agent component B is prepared.

[0017] Preparation of diluent component C: add xylene 40-55 parts, diheptanone 15-35 parts, propylene glycol methyl ether acetate 10-25 parts, cyclohexanone 5-15 parts and divalent acid ester 1-5 parts into a cylinder in sequence, and then disperse them by using a high-speed disperser, and filter them through a filter screen with a mesh size of 120-200, so that diluent component C is prepared.

[0018] Mix the base component A, the curing agent component B and the diluent component C in a mass ratio of 10:2:(1.5-2.5), and then mix them uniformly, so that the base paint product for aircraft skin is prepared.

[0019] Optionally, the preparation of the base component A further includes the preparation of polyester resin, and the preparation of the polyester resin includes the following steps.

[0020] Step S01: add tricyclodecane dimethyl alcohol 1-15 parts, hexahydrophthalic anhydride 15-45 parts, trimethylolpropane 15-45 parts, neopentyl glycol 1-10 parts and monobutyl tin oxide 0.01-1 parts into a reaction kettle;

[0021] Step S02: introduce nitrogen into the reaction kettle, heat to 85-95℃, and then heat while stirring until reflux dehydration, and start measuring the acid value;

[0022] Step S03: when the measured acid value is ≤10 mgKOH / g, discharge the solvent in the water trap of the reaction kettle, measure the total dehydration amount, and then cool while vacuumizing until the temperature is reduced to below 145℃, stop vacuumizing and keep nitrogen flowing;

[0023] Step S04: put propylene glycol methyl ether acetate 5-20 parts, diethylene glycol butyl ether acetate 3-10 parts and butyl acetate 10-25 parts into the reaction kettle, and dilute the reactants in the reaction kettle;

[0024] Step S05: continue stirring and cooling to below 80℃, stop the nitrogen flow, and filter the synthesized polyester resin in the reaction kettle through a filter screen with a mesh size of 120-200, so that the polyester resin product is prepared.

[0025] Optionally, in the process of heating while stirring in step S02, the temperature is raised to 215-225℃ for 12-14 h, and then refluxed for 1-2 h.

[0026] Compared with the prior art, the one or more technical solutions in the embodiments of the present application have at least one of the following beneficial effects:

[0027] The base color paint for aircraft skin or the base color paint for aircraft skin prepared by the preparation method in the embodiments of the present application adopts a self-made polyester resin with good weather resistance as a resin main body, and a part of slightly branched toughening resin is spliced in, which can reduce the VOC content of the resin system and meet the environmental protection requirements, and can provide more crosslinking points for the resin system, thereby toughening the resin system. The base color paint for aircraft skin provided by the embodiments of the present application has extremely low VOC, is environment-friendly, has high solid content, and has a paint film with strong hiding power, good medium resistance, excellent color and gloss retention, and overcomes the defects of the traditional coating system for aircraft skin, such as low solid content, poor color and gloss retention, weak hiding power, and high VOC content. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0029] The base color paint for aircraft skin provided by the embodiments of the present application adopts a self-made polyester resin with good weather resistance as a resin main body, and a part of slightly branched toughening resin is spliced in, which can reduce the VOC content of the resin system and meet the environmental protection requirements, and can provide more crosslinking points for the resin system, thereby toughening the resin system. The base color paint for aircraft skin provided by the embodiments of the present application uses titanium dioxide as a coloring pigment, controls the concentration of the coloring pigment to realize high hiding power of the base color paint, and simultaneously considers the mechanical properties of the coating layer, the compactness of the coating layer, and the matching with the upper and lower coating layers. The base color paint for aircraft skin provided by the embodiments of the present application has high solid content, a paint film with strong hiding power, good medium resistance, excellent color and gloss retention, and the like, is suitable for being used with a varnish for aircraft skin, and has the effect of reducing the weight of the aircraft.

[0030] The base color paint for aircraft skin provided by the embodiments of the present application includes a base component A, a curing agent component B and a diluent component C, and the base component A includes the following components in the following mass fractions:

[0031]

[0032] Specifically, the raw materials selected by the embodiment of the present application all have a purity of 99.9% or above. In this way, the base color paint for aircraft skin provided by the embodiment of the present application adopts self-made polyester resin with good weather resistance as the main resin, and incorporates part of slightly branched toughening resin, which can reduce the VOC content of the resin system and meet the environmental protection requirements, and can also provide more crosslinking points for the resin system, thus achieving better toughening effect. In addition, the base color paint for aircraft skin provided by the embodiment of the present application has a much higher pigment-to-binder ratio (the concentration of coloring pigment in the paint film) than general topcoat, and can achieve high hiding power at a lower paint film thickness. That is, the base color paint for aircraft skin provided by the embodiment of the present application uses titanium dioxide as the coloring pigment, and realizes high hiding power of the base color paint by controlling the concentration of the coloring pigment, while taking into account the mechanical properties of the coating, the compactness of the coating, and the matching with the upper and lower coatings, etc. The base color paint for aircraft skin provided by the embodiment of the present application has high construction solid content, and the paint film has the properties of strong hiding power, good medium resistance, excellent color and gloss retention, etc., and is suitable for being used in combination with varnish for aircraft skin. The material properties and on-site construction and coating performance of the coating meet the user's requirements.

[0033] Optionally, in some embodiments, when used for construction, the base component A, the curing agent component B and the diluent component C are mixed in a mass ratio of 10:2:(1.5-2.5), and the base color paint for aircraft skin is prepared after uniform mixing.

[0034] Optionally, in some embodiments, the curing agent component B includes 60-75 parts of aliphatic isocyanate polymer, 15-25 parts of butyl acetate and 5-15 parts of propylene glycol methyl ether acetate, and the aliphatic isocyanate polymer is at least one of hexamethylene diisocyanate biuret and hexamethylene diisocyanate trimer.

[0035] Optionally, in some embodiments, the diluent component C includes 40-55 parts of xylene, 15-35 parts of diheptanone, 10-25 parts of propylene glycol methyl ether acetate, 5-15 parts of cyclohexanone and 1-5 parts of divalent acid ester. The divalent acid ester is a mixture of dimethyl succinate, dimethyl glutarate and dimethyl adipate.

[0036] Optionally, in some embodiments, the hydroxyl content of the polyester resin is 6.5% to 8.5%, the solid content of the polyester resin is 68% to 72%, and the viscosity of the polyester resin is 4000 to 10000 mPa·s. If the hydroxyl content of the polyester resin is higher than 8.5%, the film is brittle and has poor impact resistance; if the hydroxyl content of the polyester resin is lower than 6.5%, the film has insufficient crosslinking density and poor medium resistance. The polyester resin with a hydroxyl content of 6.5% to 8.5% can make the film have excellent impact resistance and medium resistance.

[0037] Optionally, in some embodiments, the toughening resin is a slightly branched flexible polyester polyol resin, and the hydroxyl value of the flexible polyester polyol resin is 120 to 180 mgKOH / g. The comprehensive performance of the film is balanced by the slightly branched flexible polyester polyol, so that the film has excellent impact resistance and medium resistance.

[0038] Optionally, in some embodiments, the titanium white is a rutile titanium white, specifically at least one of imported titanium white R960, R902 or R706, the silicon dioxide is a hydrophobic fumed silicon dioxide, the anti-sagging agent is at least one of polyamide wax, polyethylene wax or polyurea, the wetting dispersant is at least one of a copolymer solution with acidic groups, a modified polyurethane high molecular dispersant or a high molecular weight block copolymer solution containing pigment affinity groups, the catalyst drier is at least one of dibutyltin dilaurate, stannous octoate or organic bismuth, and the leveling agent is at least one of BYK-331, BYK-361N or EFKA-3777.

[0039] Optionally, in some embodiments, the polyester resin is a self-made polyester resin, and the preparation steps of the polyester resin include: 1) adding tricyclodecane dimethylol 1 to 15 parts, hexahydrophthalic anhydride 15 to 45 parts, trimethylolpropane 15 to 45 parts, neopentyl glycol 1 to 10 parts and monobutyl tin oxide 0.01 to 1 part into a reaction kettle; 2) purging nitrogen into the reaction kettle, heating to 85 to 95℃, then stirring and heating until reflux dehydration, and starting to measure the acid value; 3) when the measured acid value is ≤10 mgKOH / g, emptying the solvent in the water trap of the reaction kettle, measuring the total dehydration amount, and reducing the temperature while vacuumizing until the temperature is reduced to below 145℃, stopping vacuumizing and keeping purging nitrogen; 4) adding propylene glycol methyl ether acetate 5 to 20 parts, diethylene glycol butyl ether acetate 3 to 10 parts and butyl acetate 10 to 25 parts into the reaction kettle to dilute the reactants in the reaction kettle; 5) continuing to stir and reduce the temperature to below 80℃, stopping purging nitrogen, and filtering the polyester resin synthesized in the reaction kettle through a 120 to 200 mesh filter to obtain the polyester resin finished product.

[0040] The embodiment of the present application also provides a preparation method of the base color paint for the aircraft skin.

[0041] In some embodiments, the preparation method of the base color paint for the aircraft skin provided by the embodiment of the present application comprises the following steps:

[0042] 1) preparing the base component A: adding polyester resin 10-25 parts, toughening resin 1-5 parts, titanium dioxide 48-65 parts, silicon dioxide 0.1-1 part, anti-sagging agent 1-3 parts, wetting dispersant 1-5 parts, drier 0.01-1 part, leveling agent 0.01-1 part, dimethylbenzene 5-15 parts, butyl acetate 5-10 parts, propylene glycol methyl ether acetate 1-5 parts and solvent into a cylinder in sequence, and performing dispersion treatment by using a high-speed dispersion machine, wherein the rotation speed of the high-speed dispersion machine is 800-1000 r / min, and the dispersion time of the high-speed dispersion machine is 10-20 min, so as to obtain a mixed base; grinding the mixed base into a slurry with a fineness of ≤12.5 μm, performing dispersion treatment by using a high-speed dispersion machine, wherein the rotation speed of the high-speed dispersion machine is 800-1000 r / min, and the dispersion time of the high-speed dispersion machine is 10-20 min, and filtering through a filter screen with a mesh size of 120-200, so as to prepare the base component A.

[0043] 2) preparing the curing agent component B: adding aliphatic isocyanate polymer 60-75 parts, butyl acetate 15-25 parts and propylene glycol methyl ether acetate 5-15 parts into a cylinder in sequence, and performing dispersion treatment by using a high-speed dispersion machine, wherein the rotation speed of the high-speed dispersion machine is 200-500 r / min, and the dispersion time of the high-speed dispersion machine is 20-30 min, and filtering through a filter screen with a mesh size of 120-200, so as to prepare the curing agent component B.

[0044] 3) preparing the diluent component C: adding dimethylbenzene 40-55 parts, diheptanone 15-35 parts, propylene glycol methyl ether acetate 10-25 parts, cyclohexanone 5-15 parts and bivalent acid ester 1-5 parts into a cylinder in sequence, and performing dispersion treatment by using a high-speed dispersion machine, wherein the rotation speed of the high-speed dispersion machine is 200-500 r / min, and the dispersion time of the high-speed dispersion machine is 20-30 min, and filtering through a filter screen with a mesh size of 120-200, so as to prepare the diluent component C.

[0045] 4) mixing the base component A, the curing agent component B and the diluent component C according to a mass ratio of 10:2:(1.5-2.5), and uniformly mixing, so as to prepare the base color paint for the aircraft skin.

[0046] The base color paint for aircraft skin prepared by the preparation method of base color paint for aircraft skin provided by the embodiment of the present application adopts self-made polyester resin with good weather resistance as the main resin, and incorporates part of slightly branched toughening resin, which can reduce the VOC content of the resin system and meet the environmental protection requirements, and can provide more crosslinking points for the resin system and better toughen the resin system. The preparation method of base color paint for aircraft skin provided by the embodiment of the present application can prepare the base color paint for aircraft skin with very low VOC, which is friendly to the environment, has high solid content, and has strong hiding power, good medium resistance, excellent color and gloss retention, and overcomes the defects of the traditional coating system for aircraft skin, such as low solid content, poor color and gloss retention, weak hiding power, and high VOC content. In addition, the preparation method of base color paint for aircraft skin provided by the embodiment of the present application can realize high hiding power of the base color paint by controlling the concentration of the coloring pigment, and can also consider the mechanical properties of the coating, the compactness of the coating, and the matching with the upper and lower coatings.

[0047] Optionally, in some embodiments, the preparation of the base component A further includes the preparation of the polyester resin, and the specific preparation steps of the polyester resin include:

[0048] Step S01: according to the mass fraction, 1-15 parts of tricyclodecane dimethylol, 15-45 parts of hexahydrophthalic anhydride, 15-45 parts of trimethylolpropane, 1-10 parts of neopentyl glycol and 0.01-1 parts of monobutyl tin oxide are added into a reaction kettle;

[0049] Step S02: nitrogen is introduced into the reaction kettle, and heating is performed until 85-95 DEG C, then the temperature is increased while stirring until reflux dehydration, and the acid value is measured every 1h until the acid value is less than or equal to 10 mgKOH / g; in this step, after the temperature in the reaction kettle is increased to 85-95 DEG C, the stirring is started, and then the temperature is increased until reflux dehydration, and the reflux temperature and time are recorded. In the process of increasing the temperature while stirring, the temperature is increased to 215-225 DEG C for 12-14h, and then refluxed for 1-2h;

[0050] Step S03: when the measured acid value is less than or equal to 10 mgKOH / g, the solvent in the water trap of the reaction kettle is discharged, the total dehydration amount is measured, the temperature is decreased while vacuumizing until the temperature is decreased to below 145 DEG C, the vacuumizing is stopped and nitrogen is kept flowing; in this step, the flow of the heat conducting oil valve of the reaction kettle is strictly controlled during the whole process of temperature increasing and dehydration, so as to ensure that the water is clear and transparent, the reaction temperature and the column top temperature are recorded every 1h, and the dehydration amount is recorded;

[0051] Step S04: 5-20 parts of propylene glycol methyl ether acetate, 3-10 parts of diethylene glycol butyl ether acetate, and 10-25 parts of butyl acetate are put into the reaction kettle, and the reactants in the reaction kettle are diluted;

[0052] Step S05: continue stirring and cooling to below 80℃, stop the nitrogen, filter the synthesized polyester resin in the reaction kettle through a 120-200 mesh filter, and the finished polyester resin product with good weather resistance is obtained.

[0053] In order to enable the above-mentioned implementation details and operations of the present application to be clearly understood by those skilled in the art, and the significant performance of the base color paint for aircraft skin and the preparation method thereof to be embodied, the following examples are used to illustrate the implementation of the present application.

[0054] Example 1

[0055] The preparation method of the base color paint for aircraft skin of the present application comprises the following steps:

[0056] 1) Preparation of base component A: according to the mass fraction, polyester resin 18 parts, toughening resin (flexible polyester polyol resin) 3 parts, titanium dioxide (R960) 50 parts, silicon dioxide 1 part, anti-sagging agent 1 part, wetting dispersant 3 parts, drying agent (dibutyltin dilaurate) 0.05 parts, leveling agent (BYK-331) 0.05 parts, dimethylbenzene 15 parts, and butyl acetate 5 parts are sequentially added into the cylinder, and dispersed by a high-speed disperser at a speed of 800-1000 r / min for 10-20 min. The mixed base material is ground into a slurry with a fineness of ≤12.5 μm, the solid content is measured, propylene glycol methyl ether acetate 3.9 parts is added, and the high-speed disperser is used for dispersion treatment at a speed of 800-1000 r / min for 10-20 min. The mixture is filtered through a 180 mesh filter, and the base component A is prepared.

[0057] The preparation process of the polyester resin in the base component A comprises:

[0058] Step S01: according to the mass fraction, 8 parts of tricyclodecane dimethylol, 33 parts of hexahydrophthalic anhydride, 26 parts of trimethylolpropane, 7 parts of neopentyl glycol, and 0.3 parts of monobutyl tin oxide are added into the reaction kettle;

[0059] Step S02: nitrogen is introduced into the reaction kettle, heated to 90℃, and then heated while stirring until reflux dehydration, and the reflux temperature and time are recorded. The temperature is raised to 220±5℃ in 12-14h, and the reflux is maintained for 1h. During the reflux dehydration, the acid value is measured, and each measurement is interval 1h until the acid value is ≤10 mgKOH / g;

[0060] Step S03: when the measured acid value is ≤10 mgKOH / g, the acid value is qualified, the solvent in the water separator of the reaction kettle is discharged, the total dehydration amount is measured, the temperature is lowered while vacuumizing until the temperature is lowered to below 145℃, the vacuumizing is stopped and nitrogen is kept flowing; in this step, the whole process of temperature rising and dehydration, the flow of the heat conducting oil valve of the reaction kettle is strictly controlled to ensure that the water is clear and transparent, the column top temperature of the reaction kettle is controlled to be 70-100℃, and the reaction temperature, the column top temperature and the dehydration amount are recorded every 1h;

[0061] Step S04: 12 parts of propylene glycol methyl ether acetate, 4 parts of diethylene glycol butyl ether acetate and 14 parts of butyl acetate are put into the reaction kettle, and the reactants in the reaction kettle are diluted.

[0062] Step S05: continue to stir and lower the temperature to below 80℃, stop the nitrogen flow, filter the synthesized polyester resin in the reaction kettle through a 200-mesh filter, and the polyester resin finished product is prepared.

[0063] 2) Preparation of curing agent component B: according to the mass fraction, fatty isocyanate polymer Desmodur N3300 45 parts, fatty isocyanate polymer Desmodur N75 20 parts, butyl acetate 25 parts and propylene glycol methyl ether acetate 10 parts are sequentially added into the cylinder, and dispersed by using a high-speed disperser, the rotating speed of the high-speed disperser is 200-500 r / min, the dispersion time of the high-speed disperser is 20-30 min, and the product is filtered through a 180-mesh filter, and the curing agent component B is prepared.

[0064] 3) Preparation of diluent component C: according to the mass fraction, xylene 55 parts, diheptanone 28 parts, propylene glycol methyl ether acetate 10 parts, cyclohexanone 10 parts and divalent acid ester 2 parts are sequentially added into the cylinder, and dispersed by using a high-speed disperser, the rotating speed of the high-speed disperser is 200-500 r / min, the dispersion time of the high-speed disperser is 20-30 min, and the product is filtered through a 180-mesh filter, and the diluent component C is prepared.

[0065] When used, the base component A, the curing agent component B and the diluent component C are mixed in a mass ratio of 10:2:(1.5-2.5), and after uniform mixing, the base color paint product for aircraft skin is prepared.

[0066] Example 2

[0067] The preparation method of the base color paint for aircraft skin of the embodiment of the application comprises the following steps:

[0068] 1) Preparation of base component A: add polyester resin 25 parts, toughening resin (flexible polyester polyol resin) 1 part, titanium dioxide (R902) 48 parts, silicon dioxide 0.3 part, anti-sagging agent 2 parts, wetting dispersant 1 part, drier (stannous octoate) 0.03 part, leveling agent (BYK-331) 0.07 part, leveling agent (BYK-361N) 0.9 part, xylene 12 parts, and butyl acetate 4.7 parts into a cylinder in sequence according to mass fraction, and disperse by using a high-speed disperser, the rotation speed of the high-speed disperser is 800-1000 r / min, and the dispersion time of the high-speed disperser is 10-20 min, to obtain a mixed base; grind the mixed base into a slurry with fineness ≤12.5 μm, measure the solid content, supplement with propylene glycol methyl ether acetate 5 parts, and disperse by using a high-speed disperser again, the rotation speed of the high-speed disperser is 800-1000 r / min, and the dispersion time of the high-speed disperser is 10-20 min, filter through a 200-mesh filter screen, and base component A is prepared.

[0069] The preparation process of the polyester resin in the base component A comprises the following steps:

[0070] Step S01: add tricyclodecane dimethylol 6 parts, hexahydrophthalic anhydride 15 parts, trimethylolpropane 28 parts, neopentyl glycol 5 parts, and monobutyl tin oxide 0.1 part into a reaction kettle according to mass fraction;

[0071] Step S02: introduce nitrogen into the reaction kettle, heat to 90℃, and then heat while stirring until reflux dehydration, and record the reflux temperature and time. Heat to 220±5℃ for 12-14 h, and reflux for 2 h. During reflux dehydration, start to measure the acid value, and measure every 1 h until the acid value is ≤10 mgKOH / g;

[0072] Step S03: when the measured acid value is ≤10 mgKOH / g, the acid value is qualified, discharge the solvent in the water trap of the reaction kettle, measure the total dehydration amount, and cool while vacuumizing until the temperature is reduced to below 145℃, stop vacuumizing and keep nitrogen flowing; in this step, the flow of the heat conduction oil valve of the reaction kettle is strictly controlled during the whole process of heating and dehydration, to ensure that the water is clear and transparent, the column top temperature of the reaction kettle is controlled to be 70-100℃, and the reaction temperature and column top temperature and dehydration amount are recorded every 1 h;

[0073] Step S04: put propylene glycol methyl ether acetate 10 parts, diethylene glycol butyl ether acetate 5 parts, and butyl acetate 15 parts into the reaction kettle, and dilute the reactants in the reaction kettle;

[0074] Step S05: continue to stir and cool to below 80℃, stop the nitrogen flow, filter the synthesized polyester resin in the reaction kettle through a 200-mesh filter screen, and the polyester resin finished product is prepared.

[0075] 2) Preparation of curing agent component B: according to the mass fraction, into the cylinder in turn add aliphatic isocyanate polymer Desmodur N3300 49 parts, aliphatic isocyanate polymer Desmodur N75 21 parts, butyl acetate 15 parts and propylene glycol methyl ether acetate 15 parts, using high speed dispersion machine for dispersion treatment, the speed of high speed dispersion machine is 200-500 r / min, the dispersion time of high speed dispersion machine is 20-30 min, filter through 200 mesh screen, can be prepared to obtain curing agent component B.

[0076] 3) Preparation of diluent component C: according to the mass fraction, into the cylinder in turn add xylene 45 parts, diheptanone 15 parts, propylene glycol methyl ether acetate 25 parts, cyclohexanone 10 parts and divalent acid ester 5 parts, using high speed dispersion machine for dispersion treatment, the speed of high speed dispersion machine is 200-500 r / min, the dispersion time of high speed dispersion machine is 20-30 min, filter through 200 mesh screen, can be prepared to obtain diluent component C.

[0077] When used, the base component A, curing agent component B and diluent component C are mixed in a mass ratio of 10:2:(1.5-2.5), and after uniform mixing, the base color paint product for aircraft skin is prepared.

[0078] Example 3

[0079] The preparation method of the base color paint for aircraft skin of the embodiment of the application comprises the following steps:

[0080] 1) Preparation of base component A: according to the mass fraction, into the cylinder in turn add polyester resin 10 parts, toughening resin (flexible polyester polyol resin) 5 parts, titanium dioxide (R706) 60 parts, silicon dioxide 0.1 part, anti-sagging agent 3 parts, wetting dispersant 5 parts, drier (organic bismuth) 0.05 parts, leveling agent (BYK-331) 0.09 parts, leveling agent (EFKA-3777) 0.8 parts, xylene 5 parts and butyl acetate 10 parts, using high speed dispersion machine for dispersion treatment, the speed of high speed dispersion machine is 800-1000 r / min, the dispersion time of high speed dispersion machine is 10-20 min, obtain the mixed base; the mixed base is ground into a slurry with a fineness of ≤12.5 μm, the solid content is measured, propylene glycol methyl ether acetate 1 part is added, and then high speed dispersion machine is used for dispersion treatment, the speed of high speed dispersion machine is 800-1000 r / min, the dispersion time of high speed dispersion machine is 10-20 min, filter through 120 mesh screen, can be prepared to obtain base component A.

[0081] The preparation process of the polyester resin in the base component A comprises:

[0082] Step S01: adding 7 parts of tricyclodecane dimethanol, 30 parts of hexahydrophthalic anhydride, 30 parts of trimethylolpropane, 7 parts of neopentyl glycol and 0.1 parts of monobutyltin oxide to a reaction kettle according to parts by mass;

[0083] Step S02: Pour nitrogen into the reactor, heat to 90°C, and then continue heating while stirring until reflux dehydration. Record the reflux temperature and time. Raise the temperature to 220±5°C over 12-14 hours, and reflux for 1 hour. During reflux dehydration, begin measuring the acid value, measuring every 1 hour until the acid value is ≤10mgKOH / g.

[0084] Step S03: When the measured acid value is ≤10 mgKOH / g, the acid value is qualified, the solvent in the water separator of the reactor is emptied, the total dehydration amount is measured, and the temperature is lowered while vacuuming until the temperature drops below 145°C. The vacuuming is stopped and nitrogen is maintained. In this step, during the entire process of heating and dehydration, the flow rate of the thermal oil valve of the reactor is strictly controlled to ensure that the dehydrated water is clear and transparent. The column top temperature of the reactor is controlled at 70-100°C, and the reaction temperature, column top temperature, and dehydration amount are recorded every 1 hour.

[0085] Step S04: adding 11 parts of propylene glycol methyl ether acetate, 6 parts of diethylene glycol butyl ether acetate, and 13 parts of butyl acetate into a reaction kettle to dilute the reactants in the reaction kettle;

[0086] Step S05: Continue stirring and cool the mixture to below 80° C., stop nitrogen flow, and filter the polyester resin synthesized in the reactor through a 120-mesh filter to obtain a polyester resin product.

[0087] 2) Preparation of curing agent component B: 52 parts of aliphatic isocyanate polymer Desmodur N3300, 23 parts of aliphatic isocyanate polymer Desmodur N75, 20 parts of butyl acetate, and 5 parts of propylene glycol methyl ether acetate were added to a pull cylinder in order by weight, and dispersed using a high-speed disperser at a speed of 200 to 500 r / min for 20 to 30 minutes. The mixture was filtered through a 120-mesh filter to obtain curing agent component B.

[0088] 3) Preparation of diluent component C: 40 parts of xylene, 35 parts of diheptanone, 19 parts of propylene glycol methyl ether acetate, 5 parts of cyclohexanone and 1 part of dibasic acid ester were added to the pull cylinder in order by mass, and dispersed by a high-speed disperser at a speed of 200 to 500 r / min for 20 to 30 min. The mixture was filtered through a 120-mesh filter to obtain diluent component C.

[0089] When in use, the base component A, the curing agent component B and the diluent component C are mixed in a mass ratio of 10:2:(1.5-2.5), and after being mixed uniformly, the base color paint product for the aircraft skin is prepared.

[0090] Comparative Example

[0091] The base color paint for the aircraft skin prepared in Examples 1-3 and the polyester polyurethane system base color paint for the aircraft skin on the market are used as the comparative examples.

[0092] Coating performance test:

[0093] The base color paint for the aircraft skin prepared in Examples 1-3 and the polyester polyurethane system base color paint for the aircraft skin in the comparative examples are respectively tested as follows:

[0094] 1) Container state test: the base component A and the curing agent component B should have no caking, gelation, bubbles, skin, foreign contaminants or tank rust, and the diluent component C should be clear, colorless and have no suspended solids, then the performance requirements are met.

[0095] 2) Pot life test: the pot life is greater than or equal to 3 hours, then the performance requirements are met.

[0096] 3) Fineness test: the fineness is less than or equal to 12.5 μm, then the performance requirements are met.

[0097] 4) Non-volatile content test: the non-volatile content is 75%±2%, then the performance requirements are met.

[0098] 5) VOCs content test: the VOCs content is less than or equal to 420 g / L, then the performance requirements are met.

[0099] 6) Paint film color and appearance test: the paint film color and appearance are white, the paint film is smooth and flat, then the performance requirements are met.

[0100] 7) Contrast ratio test: the contrast ratio of the paint film is greater than or equal to 0.990, then the performance requirements are met.

[0101] 8) Spray performance test: when the mixed coating is applied at a distance of 203-305 mm from the sample plate, it should have good leveling, no wrinkles, no hanging, no bubbles, no stripes or other irregularities, then the performance requirements are met.

[0102] 9) Drying time test: tape masking: ≤4 h, no sticky marks and only slight adhesion; re-spraying time: 2-120 h, then the performance requirements are met.

[0103] 10) Scribe adhesion test: no blistering after immersion in water, and the adhesion should be above level 7, then the performance requirements are met.

[0104] 11) Flexibility test: no crack, flaking and no adhesion failure by conical mandrel bend test, then it meets the performance requirement.

[0105] 12) Impact resistance test: no crack or coating flaking when subjected to 91 kg-cm (80 in-lb) of positive and reverse impact, then it meets the performance requirement.

[0106] 13) Pencil hardness test: pencil hardness is greater than or equal to HB, then it meets the performance requirement.

[0107] 14) Phosphate ester hydraulic oil resistance test: no blister, crack, flaking or other defects after immersion in phosphate ester hydraulic oil for 30-32 days, and pencil hardness is greater than or equal to 2B, then it meets the performance requirement.

[0108] 15) Distilled water resistance test: no blister, crack, flaking or other defects after immersion in distilled water for 14-16 days, and pencil hardness is greater than or equal to B, then it meets the performance requirement.

[0109] 16) Artificial aging test: light exposure for 4 h by UVB-313, heat and humidity for 4 h, total test for 1500 h, gloss retention is greater than or equal to 90%, and color retention ΔE*ab is less than or equal to 3, then it meets the performance requirement.

[0110] 17) Clear varnish matching test: clear varnish and basecoat interlayer adhesion should be greater than or equal to 7, then it meets the performance requirement.

[0111] The performance test results of the basecoat paint for aircraft skin prepared in Examples 1-3 and the polyester polyurethane system basecoat paint for aircraft skin in the comparative example are listed in Table 1 below.

[0112] Table 1 Test results of the basecoat paint for aircraft skin in Examples 1-3 and the polyester polyurethane system basecoat paint for aircraft skin in the comparative example

[0113]

[0114] As can be seen from Table 1, the basecoat paint for aircraft skin prepared in Examples 1-3 has high construction solid content, good matching with clear varnish, and the paint film has the characteristics of strong hiding power, good medium resistance, excellent color and gloss retention, and the like, and the coating performance completely meets the protection and decoration requirements of aircraft skin.

[0115] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A base color paint for aircraft skin, characterized in that: The base color paint for aircraft skin comprises a base material component A, a curing agent component B and a diluent component C, wherein the base material component A comprises the following components in the following parts by mass: 10-25 parts of polyester resin; 1 to 5 parts of toughening resin; 48-65 parts of titanium dioxide; 0.1-1 part of silicon dioxide; 1 to 3 parts of anti-sagging agent; 1 to 5 parts of wetting and dispersing agent; 0.01 to 1 part of drying agent; Leveling agent 0.01 to 1 part; 5-15 parts of xylene; 5-10 parts of butyl acetate; 1-5 parts of propylene glycol methyl ether acetate; Wherein, the mass ratio of the base material component A, the curing agent component B and the diluent component C is 10:2:(1.5-2.5), The curing agent component B comprises, by weight, 60 to 75 parts of an aliphatic isocyanate polymer, 15 to 25 parts of butyl acetate, and 5 to 15 parts of propylene glycol methyl ether acetate; the aliphatic isocyanate polymer is a mixture of hexamethylene diisocyanate biuret and hexamethylene diisocyanate trimer; the toughening resin is a slightly branched flexible polyester polyol resin, and the hydroxyl value of the flexible polyester polyol resin is 120 to 180 mgKOH / g. The preparation steps of the polyester resin include: Step S01: adding 1-15 parts of tricyclodecane dimethanol, 15-45 parts of hexahydrophthalic anhydride, 15-45 parts of trimethylolpropane, 1-10 parts of neopentyl glycol and 0.01-1 part of monobutyltin oxide into a reaction kettle; Step S02: nitrogen is introduced into the reactor, and the mixture is heated to 85-95° C., and the temperature is raised while stirring until the mixture is refluxed and dehydrated, and the acid value is measured; Step S03: When the measured acid value is ≤10 mgKOH / g, the solvent in the water separator of the reactor is vented, the total dehydration amount is measured, and vacuum is applied while the temperature is lowered until the temperature drops below 145° C., then the vacuum is stopped and nitrogen is maintained. Step S04: adding 5-20 parts of propylene glycol methyl ether acetate, 3-10 parts of diethylene glycol butyl ether acetate, and 10-25 parts of butyl acetate into a reaction kettle to dilute the reactants in the reaction kettle; Step S05: Continue stirring and cool the mixture to below 80° C., stop nitrogen flow, and filter the polyester resin synthesized in the reactor through a 120-200 mesh filter to obtain a polyester resin product.

2. The base color paint for aircraft skin according to claim 1, characterized in that: Calculated by mass, the diluent component C includes 40-55 parts of xylene, 15-35 parts of diheptanone, 10-25 parts of propylene glycol methyl ether acetate, 5-15 parts of cyclohexanone and 1-5 parts of dibasic acid ester.

3. The base color paint for aircraft skin according to claim 1, characterized in that: The wetting and dispersing agent is at least one of a copolymer solution having an acidic group, a modified polyurethane polymer dispersant, and a high molecular weight block copolymer solution containing a pigment affinity group.

4. The base color paint for aircraft skin according to claim 1, characterized in that: The hydroxyl content of the polyester resin is 6.5% to 8.5%, the solid content of the polyester resin is 68% to 72%, and the viscosity of the polyester resin is 4000 to 10000 mPa·s.

5. A method for preparing a base color paint for aircraft skin according to any one of claims 1 to 4, characterized in that: The steps include: Preparation of base material component A: adding 10-25 parts of polyester resin, 1-5 parts of toughening resin, 48-65 parts of titanium dioxide, 0.1-1 part of silicon dioxide, 1-3 parts of anti-sagging agent, 1-5 parts of wetting and dispersing agent, 0.01-1 part of drying agent, 0.01-1 part of leveling agent, 5-15 parts of xylene, 5-10 parts of butyl acetate and 1-5 parts of propylene glycol methyl ether acetate to a pull cylinder in sequence, and dispersing the mixture using a high-speed disperser to obtain a mixed base material; grinding the mixed base material into a slurry with a fineness of ≤12.5 μm, dispersing the mixture using a high-speed disperser, and filtering the mixture through a 120-200 mesh filter to obtain the base material component A; Preparation of curing agent component B: Add 60-75 parts of aliphatic isocyanate polymer, 15-25 parts of butyl acetate and 5-15 parts of propylene glycol methyl ether acetate to a pull cylinder in sequence, disperse them using a high-speed disperser, and filter through a 120-200 mesh filter to prepare curing agent component B; Preparation of diluent component C: 40-55 parts of xylene, 15-35 parts of diheptanone, 10-25 parts of propylene glycol methyl ether acetate, 5-15 parts of cyclohexanone and 1-5 parts of dibasic acid ester are sequentially added to a pull cylinder, dispersed using a high-speed disperser, and filtered through a 120-200 mesh filter to prepare diluent component C; The base material component A, the curing agent component B and the diluent component C are mixed in a mass ratio of 10:2:(1.5-2.5), and after mixing evenly, a base color paint product for aircraft skin is prepared.

6. The method for preparing a base color paint for aircraft skin according to claim 5, characterized in that: In the step S02, the temperature is raised to 215-225° C. over 12-14 hours while stirring, and the mixture is refluxed and kept warm for 1-2 hours.

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