CN110564271B

CN110564271B - Solvent high-gloss base coat for skin

Info

Publication number: CN110564271B
Application number: CN201910924843.3A
Authority: CN
Inventors: 郭年华; 薛玉华; 阮润琦; 步明升; 王黎; 汪威; 张岩
Original assignee: Marine Chemical Research Institute Co Ltd
Current assignee: Marine Chemical Research Institute Co Ltd
Priority date: 2019-09-27
Filing date: 2019-09-27
Publication date: 2021-03-19
Anticipated expiration: 2039-09-27
Also published as: CN110564271A

Abstract

The invention discloses a solvent high-gloss base color paint for skins, which is a three-component solvent polyurethane enamel, wherein a base material comprises the following components: polyester resin, pigment, functional filler, wetting dispersant, substrate wetting agent, defoaming agent, leveling agent, light stabilizer, anti-settling agent and the like. The curing agent is polyester modified isocyanate and ester solvent. The diluent is classified into ester solvents, ketone solvents and other solvents. The developed skin solvent type high-gloss base coat has the advantages of high solid content, good fullness, excellent mechanical property, medium resistance, low VOC, low light loss rate, excellent weather resistance, corrosion resistance, construction performance and the like. The coating experiment of the external skin proves that the coating can be completely popularized and used in a large range of the outside of an airplane, an automobile, a locomotive and the like, and has considerable use value and economic value.

Description

Solvent high-gloss base coat for skin

Technical Field

The invention relates to the field of functional coatings, in particular to a skin solvent type high gloss base coat which is developed and has the advantages of high solid content, good fullness, excellent mechanical property, medium resistance, low VOC, low light loss rate, excellent weather resistance, corrosion resistance, construction performance and the like. The paint can be coated on the outer parts of airplanes, automobiles, locomotives and the like, and has considerable use value and economic value.

Background

The aircraft skin coating is protective and decorative coating for the exterior of an aircraft, and plays an important role in prolonging the service life of the aircraft and ensuring the safety of the aircraft.

With the increasing global environmental protection requirements and the restriction of V0C (volatile organic content in paint) in the international decorative paint market, the paint with low pollution by using low solvent has become a great trend, and especially the high-solid paint with low solvent is developed most rapidly and is applied most widely. In recent years, the high-solid aviation coatings of PPG Aerospace, AKZ 0N 0BEL and the like are widely used on airplanes such as Boeing, Airbus and the like; even some military aircraft in China begin to use high-solid coatings.

Aircraft skin coating since the nineties, foreign companies have been working on skin coating systems, the respective directions of research are different, but the final goal is to provide aircraft skin coatings with high weather resistance and high corrosion resistance. The research on the high weather-resistant coating is developed from the beginning of the century domestically, and certain achievements are obtained. For a new skin coating system (primer, base paint and varnish), the research on the system is not developed at home, and the research on the development and the matching of the new skin coating system with high weather resistance and high corrosion resistance is developed at home first by the limited company of the ocean chemical research institute.

From the development trend of the world aviation coating, the characteristics of low VOC, high efficiency and environmental protection are the inevitable development trend of the aircraft coating. The successful development and the engineering application of the coating on large airplanes can obviously improve the technical level of aviation coatings and coatings in China, promote the development of aviation coating materials and corrosion protection systems to high-performance and green directions, and accelerate the process of connecting aviation functional materials in China with international advanced levels.

Disclosure of Invention

The invention aims to provide a skin solvent type high-gloss base coat which has the advantages of high solid content, good fullness, excellent mechanical property, medium resistance, low VOC, low light loss rate, excellent weather resistance, corrosion resistance, construction performance and the like, can be coated on the outer parts of airplanes, automobiles, locomotives and the like, and has considerable use value and economic value.

The skin solvent type highlight base coat is divided into three components, namely a base material, a curing agent and a diluent, wherein the ratio of the base material to the curing agent to the diluent is 2:0.8:1, and the components are as follows:

the polyester resin is used as Changxing resin and imported Coresian resin; the pigment is imported titanium dioxide pigment R930 or R760, and each pigment is Basff; the functional filler is one or a mixture of more of superfine talcum powder, superfine barium sulfate and mica powder; the wetting dispersant is a copolymer containing an acidic group or a block copolymer containing a basic pigment affinity group; the substrate wetting agent is polyacrylate solution; the anti-settling agent is a high molecular polymer or modified urea containing amino and acid groups; the defoaming agent is modified polysiloxane solution or acrylate solution; the flatting agent is one or a mixture of more of fluorocarbon modified or special modified acrylate copolymers; the light stabilizer is a mixture of one or more of an ultraviolet absorbent and hindered amine; the isocyanate is a synthesized polyester modified isocyanate compound, and can remarkably improve the performances such as paint film fullness, toughness, adhesive force between coating interlayers and the like by introducing soft segment ester groups, and the synthetic route is as follows:

adding 10-15% of polyester resin and 10-15% of xylene into a reaction kettle, heating to 140 ℃ for dehydration for 1 hour, cooling to 40 ℃ after dehydration is finished, adding 4-8% of trimethylolpropane, 10-15% of butyl acetate, 15-20% of propylene glycol methyl ether acetate and 0.2-0.4% of N, N-dimethyl p-toluidine, fully and uniformly stirring, introducing nitrogen for protection, adding 10-15% of isophorone diisocyanate and 10-15% of hexamethylene diisocyanate, uniformly stirring, slowly heating after the addition is finished, reacting at the constant temperature of 50-70 ℃ for 4-6 hours, adding 0.2% of phosphoric acid liquid with the content of 1%, fully stirring to terminate the reaction, cooling to below 40 ℃, filtering and discharging.

The ester solvent is one or more of ethyl acetate, n-butyl acetate, isobutyl isobutyrate, tert-butyl acetate and propylene glycol methyl ether acetate; the ketone solvent is one or more of methyl isobutyl ketone, methyl n-amyl (methyl) ketone and acetylacetone; the benzene solvent is one or a mixture of more of dimethylbenzene, No. 100 solvent naphtha and No. 150 solvent naphtha.

The solvent-based high-gloss base coat for the aircraft skin is divided into a base material, a curing agent and a diluent, and the preparation method of the base material comprises the following steps:

and (4) material getting according to the operation instruction sheet, material weighing according to the operation instruction sheet, one-man operation and one-man rechecking. Premixing rotating speed control (300-1200) r/min (low-power high-speed stirrer) for producing products below 100kg, and premixing rotating speed control (500-1200) r/min (high-power high-speed stirrer) for producing products above 100kg, wherein stirring time is preferably sufficient and uniform, and generally about 30 min. Grinding after pre-dispersing, and controlling the temperature of the grinding cavity of the sand mill to be less than or equal to 65 ℃ by adjusting the flow of condensed water and paying attention to the temperature change of the sand mill in the grinding process. The pressure of the feed inlet of the sand mill is adjusted to be below 2.0bar, and the feed flow is kept stable. And (4) grinding for 2-4 cycles, and cleaning the material tank after feeding according to requirements after grinding of each cycle is finished. And (3) from the 2 nd cycle, performing fineness inspection by inspectors every time the grinding is completed, stopping grinding when the Hergeman fineness is more than or equal to 7, and otherwise, performing the next cycle until the fineness meets the requirement. Then mixing colors, carrying out factory inspection after the color difference process is qualified, filtering and packaging after the factory inspection is qualified, putting into a finished product warehouse, and marking a table for identification.

The preparation method of the curing agent comprises the following steps:

and (4) material getting according to the operation instruction sheet, material weighing according to the operation instruction sheet, one-man operation and one-man rechecking. Premixing the products with the speed of less than 100kg for production (100-500) r/min (low-power high-speed stirrer), and premixing the products with the speed of more than 100kg for production (150-500) r/min (high-power high-speed stirrer), wherein the stirring time is about 20 min. And then, the product is delivered for inspection, filtered and packaged after the product is qualified, and is put into a finished product warehouse and marked with an identifier.

The preparation method of the diluent comprises the following steps:

and (4) material getting according to the operation instruction sheet, material weighing according to the operation instruction sheet, one-man operation and one-man rechecking. Premixing rotating speed control (100-350) r/min (low-power high-speed stirrer) for producing products below 100kg, premixing rotating speed control (100-350) r/min (high-power high-speed stirrer) for producing products above 100kg, and stirring time is about 10 min. And then, the product is delivered for inspection, filtered and packaged after the product is qualified, and is put into a finished product warehouse and marked with an identifier.

The construction process of the solvent high-gloss base color paint for the aircraft skin comprises the following steps:

firstly, base material treatment, wherein the surface treatment comprises surface treatment of the base material before coating and treatment of a base coat in the coating process. The main procedures of the surface treatment of the substrate include the steps of removing residual paint remover by warm water washing, cleaning grease by solvent, oxidizing the surface, sanding the surface, finely cleaning the surface by using a special cleaning agent matched with the paint and drying. After the surface of the general aluminum alloy substrate is cleaned, the surface of the general aluminum alloy substrate is oxidized by alotin or chromic acid, and the surface is recommended to be coated with a base coat within 24 hours. The treatment of the primary coat in the coating process mainly comprises the steps of carrying out reactivation and fine polishing treatment on the primary coat, improving the wetting capacity of the top coat on the primary coat, and removing dust particles and pollution on the surface of the primary coat.

The high-solid paint is generally composed of three parts of base stock, curing agent and diluent, the component A is stirred uniformly before construction, then the component A and the component B are mixed in proportion and stirred uniformly, the diluent is added and then stirred uniformly, the construction viscosity of a general product is between 12s and 25s, the general product is kept stand and cured for 5 to 20 minutes, in order to avoid the interference of impurities, a filter screen with more than 240 meshes is recommended to be used for filtering and then spraying, and the thickness of a dry film is controlled to be 25 to 35 mu m in a single pass. Because of the complexity and variety of parts in the current aircraft factory, the common air spraying method is generally adopted, but the whole spraying of the individual factory starts to change to the electrostatic spraying method. The common air spraying is preferably carried out with the nozzle size of the spray gun of 1.2-1.5 mm and the atomization pressure of the spray gun of 2-3 bar. The electrostatic spraying is preferably carried out at a spray nozzle size of 1.2-1.5 mm, an inflow pressure of 2-3 bar, an outflow pressure of 0.5-1 bar, and an atomization pressure of 3-4.5 bar. During operation, the spray gun should move at a constant speed with a moderate distance and spray vertically to the coating surface. During the painting process, the arm should be kept stable to ensure that each part is painted the same amount of paint.

The technical indexes to be achieved by the skin solvent type highlight base coat are as follows:

the developed skin solvent high-gloss base color paint coated on the surface of the metal material such as aluminum alloy and the like has good adhesive force with a base material, good mechanical properties, medium resistance, weather resistance, corrosion resistance and other characteristics, and good process performance, and meets the coating process requirements on the surface of the metal material such as aluminum alloy and the like.

The specific performance index achieved is shown in table 1.

TABLE 1 coating Performance requirements

Detailed Description

The invention is further illustrated by the following examples, but is in no way limited to these examples. White and yellow aircraft skin coatings are taken as implementation cases, the coatings are prepared according to the production process of the invention, and the formula is shown in examples 1 and 2; meanwhile, white aircraft skin paint is taken as a base material, different curing agents are used, the performance of the self-synthesized polyester modified isocyanate is compared with that of the isocyanate widely applied in the market, the formula and the performance test result are shown in an example 3, and the formula and the performance test result are shown in a table 2 and a table 3:

example 1:

the skin solvent high-gloss base coat is white, and the base materials comprise the following components in percentage by weight:

30 parts of polyester resin, 30 parts of titanium white R70630 parts, 10 parts of superfine barium sulfate, 1.5 parts of wetting dispersant, 0.3 part of base material wetting agent, 2.0 parts of anti-settling agent, 0.1 part of defoaming agent, 2.0 parts of flatting agent, 4 parts of ultraviolet absorbent, 1 part of hindered amine antioxidant, 13.1 parts of n-butyl acetate solvent and 6 parts of propylene glycol methyl ether acetate.

The curing agent comprises the following components in percentage by weight:

78 parts of self-synthesized polyester modified isocyanate and 22 parts of n-butyl acetate.

The diluent comprises the following components in percentage by weight:

59 parts of n-butyl acetate, 6 parts of propylene glycol methyl ether acetate, 20 parts of methyl isobutyl ketone and 15 parts of xylene.

Example 2:

the skin solvent high-gloss base color paint is yellow, and the base materials comprise the following components in percentage by weight:

30 parts of polyester resin, 25 parts of bismuth vanadate yellow, 15 parts of superfine barium sulfate, 1.0 part of wetting dispersant, 0.2 part of base material wetting agent, 2.0 parts of anti-settling agent, 0.2 part of defoaming agent, 2.0 parts of flatting agent, 4.4 parts of ultraviolet absorbent, 1.1 parts of hindered amine antioxidant, 6 parts of ethyl acetate, 7.1 parts of n-butyl acetate solvent and 6 parts of propylene glycol methyl ether acetate.

The curing agent comprises the following components in percentage by weight:

80 parts of polyester modified isocyanate and 20 parts of n-butyl acetate.

The diluent comprises the following components in percentage by weight:

55 parts of n-butyl acetate, 10 parts of propylene glycol methyl ether acetate, 20 parts of methyl isobutyl ketone and 15 parts of xylene.

Example 3: TABLE 2 curative formulations in combination with the base materials of example 1 and testing of the properties are given in Table 3

TABLE 2 formulation

TABLE 3 test results

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any person skilled in the art may modify or modify the technical details disclosed above into equivalent embodiments with equivalent variations. However, any simple modification, equivalent change or modification made to the above embodiments according to the technical essence of the present invention, without departing from the technical solution of the present invention, still belongs to the protection scope of the technical solution of the present invention.

Claims

1. The skin solvent type highlight base coat is characterized by comprising three components, namely a base material, a curing agent and a diluent, wherein the ratio of the base material to the curing agent to the diluent is 2:0.8:1, and the components are as follows:

the synthetic route of the polyester modified isocyanate comprises the following steps:

adding 10-15% of polyester resin and 10-15% of xylene into a reaction kettle, heating to 140 ℃ for dehydration for 1 hour, cooling to 40 ℃ after dehydration is finished, adding 4-8% of trimethylolpropane, 10-15% of butyl acetate, 15-20% of propylene glycol methyl ether acetate and 0.2-0.4% of N, N-dimethyl p-toluidine, fully and uniformly stirring, introducing nitrogen for protection, adding 10-15% of isophorone diisocyanate and 10-15% of hexamethylene diisocyanate, uniformly stirring, slowly heating after the addition is finished, reacting for 4-6 hours at a constant temperature of 50-70 ℃, adding 0.2% of phosphoric acid solution with the content of 1%, fully stirring to terminate the reaction, cooling to below 40 ℃, filtering, discharging and packaging, wherein the preparation method of the base material comprises the following steps:

premixing rotating speed of products below 100kg in premixing production is controlled to be 300-1200 r/min, premixing rotating speed of products above 100kg in production is controlled to be 500-1200 r/min, stirring time is proper for sufficient stirring and uniform stirring, generally stirring time is about 30min, grinding is carried out after pre-dispersion, temperature change of a sand mill is noticed in the grinding process, the temperature of a grinding cavity of the sand mill is controlled to be less than or equal to 65 ℃ by adjusting condensed water flow, the pressure of a feed inlet of the sand mill is adjusted to be below 2.0bar, feeding flow is kept stable, grinding is carried out for 2-4 cycles, after grinding of each cycle is finished, a material tank with fed materials is cleaned according to requirements, from 2 cycle, each time of grinding is finished, inspectors carry out fineness inspection, the Hergeman fineness is not less than 7, grinding is stopped, otherwise, next cycle is carried out until the fineness reaches the requirements, then, after the product is qualified after delivery inspection, filtering and packaging the product, putting the product into a finished product warehouse, and marking a mark;

the preparation method of the curing agent comprises the following steps:

premixing products produced below 100kg at a rotation speed of 100-500 r/min, premixing products produced above 100kg at a rotation speed of 150-500 r/min, stirring for about 20min, and performing factory inspection, filtering, packaging, storing in a finished product warehouse, and labeling;

the preparation method of the diluent comprises the following steps:

premixing the products with the volume of less than 100kg for production, controlling the premixing rotating speed at 100-350 r/min, premixing the products with the volume of more than 100kg for production, controlling the premixing rotating speed at 100-350 r/min, stirring for about 10min, then, carrying out factory inspection, filtering and packaging after the factory inspection is qualified, putting the products into a finished product warehouse, and marking a table for identification.

2. The skin solvent-borne high-gloss base coat according to claim 1, wherein the polyester resin is Changxing resin or imported Corsia resin.

3. The skin solvent type high-gloss base paint according to claim 1, wherein the pigment is imported titanium dioxide pigment R930 or R760, each pigment of Basv color, and the functional filler is one or a mixture of more of superfine talcum powder, superfine barium sulfate and mica powder.

4. The skin solvent type high gloss base coat according to claim 1, wherein the wetting dispersant is an acidic group-containing copolymer or a basic pigment affinity group-containing block copolymer, the substrate wetting agent is a polyacrylate solution, and the anti-settling agent is a high molecular type amino and acid group-containing polymer or modified urea.

5. The skin solvent type high-gloss base coat according to claim 1, wherein the defoaming agent is a modified polysiloxane solution or an acrylate solution, and the leveling agent is one or a mixture of fluorocarbon modified or specially modified acrylate copolymer.

6. The skin solvent type high-gloss base coat according to claim 1, wherein the light stabilizer is a mixture of one or more of ultraviolet absorbers and hindered amines.

7. The skin solvent-borne highlight base coat according to claim 1, characterized in that the ester solvent is one or a mixture of several of ethyl acetate, n-butyl acetate, isobutyl isobutyrate, t-butyl acetate, propylene glycol methyl ether acetate, the ketone solvent is one or a mixture of several of methyl isobutyl ketone, methyl n-amyl (methyl) ketone and acetylacetone, and the benzene solvent is one or a mixture of several of xylene, 100 # solvent oil and 150 # solvent oil.

8. The solvent-borne high-gloss base coat for the skin of an aircraft according to claim 1, wherein the solvent-borne high-gloss base coat for the skin of the aircraft is prepared by the following steps: the surface treatment of the substrate comprises two types of surface treatment of the substrate before coating and treatment of the primary coat in the coating process, wherein the main procedures of the surface treatment of the substrate comprise the steps of flushing with warm water to remove residual paint remover, cleaning grease with solvent, oxidizing the surface, sanding the surface, finely cleaning the surface with special cleaning agent matched with paint and drying, after the surface of a common aluminum alloy substrate is cleaned, oxidizing the surface with alotin or chromic acid, coating the primary coat within 24 hours, and treating the primary coat in the coating process, namely, mainly carrying out reactivation and fine polishing treatment on the primary coat, so that the infiltration capacity of the primary coat on the surface is improved, and dust particles and pollution on the surface of the primary coat are removed.