WO2023010997A1 - Low-voc organic solvent-free heat-resistant water-based paint and high-temperature-resistant corrosion-resistant coating prepared therefrom - Google Patents

Abstract

The present invention relates to the technical field of paint, and particularly to heat-resistant paint, in particular to low-VOC organic solvent-free heat-resistant water-based paint and a high-temperature-resistant corrosion-resistant coating prepared therefrom. The low-VOC organic solvent-free heat-resistant water-based paint is mainly prepared from the following raw materials: 5-30% of engineering plastic particles, 0-15% of PTFE, 0.1-2% of a pigment, 0.5-5% of a functional filler, 0.1-5% of a functional aid, and the balance of water, wherein the entirety of the raw materials is 100% by weight. The engineering plastic particles are added in the form of an engineering plastic dispersion. The low-VOC organic solvent-free heat-resistant water-based paint of the present invention does not contain any organic solvent, and the film-forming baking temperature is low. The matrix resin of the paint is the engineering plastic dispersion. The organic solvent refers to an organic solvent such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and benzene.

Description

Low VOC organic solvent-free hot water resistant coating and the high temperature and corrosion resistant coating prepared therefrom technical field

The invention relates to a heat-resistant coating, in particular to a low-VOC organic-solvent-free hot water-resistant coating and a high-temperature-resistant and corrosion-resistant coating prepared therefrom, belonging to the technical field of coatings.

Background technique

Heat-resistant coatings have been widely used in industrial protection, cooking utensils, and household appliances. Solvate.

Patent CN104974661 discloses a technical scheme of polyethersulfone ultrafine powder and its material application. The polyethersulfone ultrafine powder described in this patent is obtained by grinding, has an irregular structure, and is a solid particle. During the film formation process, It must be supplemented with solvents (see its examples), failing to achieve environmental improvement.

Patents CN1302047 and CN1305936 disclose a method for manufacturing water-based polyethersulfone dispersion liquid and redispersible polyarylethersulfone micropowder. The surfactants described in the two patents decompose and volatilize at a high temperature, resulting in polyethersulfone During the baking and film forming process, a large amount of surfactant cracks remain, which seriously affects the compactness and adhesion of the coating film. The degradation products of the surfactant are biohormone compounds, which pose health risks.

Patent C08J 3/12 discloses a method for preparing spherical polyarylene ether sulfone or polyarylene ether ketone micropowder. This patent discloses a method for preparing microspheres by spraying polymer solution. This method consumes a large amount of solvent. Moreover, the energy consumption is high, the particle size is large and the distribution is wide, and the applicable surface of the product is limited.

The application of coatings for engineering plastics is mainly divided into oil-based coatings, water-based coatings, and powder coatings. Oil-based coatings have been phased out by the state due to high VOC emissions; at present, water-based coatings mainly use high-temperature solvents for water-soluble engineering plastics to facilitate coating. Film binding force, although it is still inevitable to add a certain proportion of solvents, compared with oil-based paints, water-based paints greatly reduce VOC emissions; powder coatings are completely solvent-free, and the current mainstream resin powder manufacturing process, pollution Large, high energy consumption, more restrictions on coating construction. The invention can process specified engineering plastics into hollow particles of 0.1-2 μm through a special surfactant system and a solvent evaporation process, so as to realize the melting and film-forming of engineering plastics in a solvent-free state of water-based coatings. Similarly, the engineering plastic dispersion of the present invention is completely dried, and the dried engineering plastic particles will also be suitable for powder coatings.

Contents of the invention

The purpose of the present invention is to provide a low-VOC organic-solvent-free hot-water-resistant coating, which does not contain organic solvents, and can still provide excellent paint film performance when the formula structure remains unchanged and only the organic solvent is removed. The film-forming baking temperature is relatively low (the film-forming baking temperature is 280-380° C. for 10 minutes).

The invention also provides a preparation method of the heat-resistant and hydrolysis-resistant engineering plastic dispersion.

The technical solution adopted by the present invention to solve its technical problems is:

A low-VOC organic solvent-free hot water resistant coating, the coating is mainly made of the following raw materials:

Engineering plastic particles 5-30%,

PTFE 0～15%,

Pigment 0.1～2%,

Functional filler 0.5～5%,

Functional additives 0.1～5%,

Water surplus, the total weight of the above-mentioned raw materials is 100%;

The engineering plastic particles are added in the form of engineering plastic dispersion liquid, which is obtained by emulsification-solvent evaporation method. The engineering plastic particle diameter in the engineering plastic dispersion liquid is 0.1-2 μm, and has a hollow spherical shape. Or a spherical structure; the engineering plastic dispersion is composed of 10-75 wt% of engineering plastic particles, 0.5-10 wt% of surfactant, and the balance is water.

The low-VOC, organic-solvent-free, hot-water-resistant coating of the present invention does not contain organic solvents, and the film-forming baking temperature is relatively low (the film-forming baking temperature is 280-380°C, 10min), and the main resin of the coating is engineering plastic dispersion . The organic solvent refers to organic solvents such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and benzene.

Preferably, the engineering plastic is selected from one or a combination of polyethersulfone, polyphenylenesulfone, polyetherimide, polysulfone, polyaryletherketone, polyarylethersulfoneketone.

As preferably, the engineering plastic particles in the engineering plastic dispersion are engineering plastics, or contain 0.5-10% of engineering plastics by mass, carbon nanotubes (CNTs), acidified carbon nanotubes, nano-boron nitride, graphene , graphene oxide, nano-mica, nano-bentonite or a mixture of several modified engineering plastics.

Preferably, the solvent is one or a mixture of dichloromethane, trichloromethane, dichloroethane, trichloroethane, carbon disulfide, the boiling point is 40 ~ 80 ℃ (0.1MPa, room temperature 25-27 ℃),

More preferably, the boiling point ranges from 45 to 75°C;

The most preferred boiling point range is 55-65°C.

Preferably, the emulsifying surfactant is an anionic surfactant of A ^- B ⁺ structure, wherein A ^- is an alkyl carboxylate structure of the molecular formula C _n H _2n-1 O ₂ ^- , wherein n is 8-16; B ⁺ is selected from NH ₄ ⁺ , Na ⁺ , K ⁺ .

Preferably, in the A ^- structure of the surfactant, the value of n is preferably 10-14.

Preferably, the surfactant is intermixed with two materials with different n values, and the ratio of the two is 0.1-0.9:1. Materials with different n values are more effective when used with each other.

As a preference, in the A ^- structure of the surfactant, A is preferably a straight-chain alkanyl carboxylate; B ⁺ is preferably Na ⁺ .

More preferably, the composition of the engineering plastic dispersion is 25-55 wt% of engineering plastic particles, 0.5-5 wt% of surfactant, and the balance is water. More preferably, the composition of the engineering plastic dispersion is 35-40 wt% of engineering plastic particles, 0.5-3 wt% of surfactant, and the balance is water. More preferably, the composition of the engineering plastic dispersion is 35-40 wt% of engineering plastic particles, 0.5-1 wt% of surfactant, and the balance is water.

Preferably, the engineering plastic particles in the engineering plastic dispersion have a statistical value of particle size D50≤1 μm and D100≤2 μm; the engineering plastic particles in the engineering plastic dispersion have an average hollow ratio of not less than 25%.

Preferably, the pigment is selected from monoazo pigments, disazo pigments, azo lake pigments, naphthol AS pigments, phthalocyanine blue, phthalocyanine green, other metal phthalocyanines, quinacridone pigments , Benzimidazolone pigments, dioxazine pigments, anthrone pigments and other organic pigments or a mixture of several. The pigment may also be one or a mixture of titanium dioxide, zinc sulfide, zinc oxide, cadmium pigments, chromic acid pigments, ultramarine blue pigments, iron blue pigments, and carbon black pigments.

Preferably, the functional filler is selected from quartz, barium sulfate, titanium dioxide, chromium dioxide, zinc oxide, iron oxide, aluminum oxide, silicon oxide, zirconia aluminum silicate, aluminum magnesium silicate, silicon carbide, titanium carbide, Silicon nitride, titanium nitride, cubic boron nitride, barium sulfate whiskers, calcium carbonate whiskers, carbon fiber powder, glass fiber powder, quartz fiber powder, carbon nanotubes, graphene oxide, graphene, basalt fiber, mica, One or a mixture of talcum powder, hexagonal boron nitride or graphite.

As a preference, the functional fillers may be pre-surface-treated with silane coupling agents and organic polymers. Example 10 is a comparative example. The functional fillers have not been surface-treated and exhibit lower salt water resistance.

As a preference, the functional additive may be a combination of common commercially available leveling agents, anti-settling agents, anti-sagging stabilizers, wetting agents, defoamers, rust inhibitors, and thixotropic agents.

The functional auxiliary agent can be inorganic, organic-inorganic hybrid, organic, or a combination of several types of auxiliary agents. The inorganic functional additives may be inorganic mineral materials, and/or artificially synthesized mineral materials. The organic-inorganic hybrid and organic functional additives can be silicones, polyoxyethylenes, polyacrylates, celluloses, polyamides, organic fluorides, mineral oils, carboxylates Polymers, polycarbonates. The organic-inorganic hybrid and organic functional additives preferably have a boiling point and/or degradation temperature range of 100-350°C. More preferably, the boiling point and/or degradation temperature range is 150-320°C. Optimally, the boiling point and/or degradation temperature range is 200-280°C.

A kind of preparation method of described engineering plastics dispersion liquid, this method comprises the steps:

S1. Dissolve engineering plastic particles and surfactants in a solvent, and use the solvent to control the viscosity of the system to 50-1000Pa.s;

S2. Add water to the material obtained in step S1 under stirring at 300-800 rpm to obtain an oil-in-water emulsion;

S3. The oil-in-water emulsion is evaporated and concentrated to obtain the water-based engineering plastic dispersion.

Preferably, the viscosity of the system is controlled by a solvent to be 100-500 Pa.s, more preferably the viscosity of the system is 150-250 Pa.s.

Preferably, the solvent evaporation process is in the form of flash evaporation, and the oil-in-water emulsion evaporates the solvent quickly by heating with atomized steam or heating with wiped film evaporation. The solvent evaporation process is fast and efficient, and the system does not introduce normal temperature gas.

The invention relates to a high-temperature-resistant and corrosion-resistant coating obtained by coating the low-VOC organic-solvent-free hot water-resistant coating.

A method for preparing a high-temperature-resistant and corrosion-resistant coating. The raw materials of the low-VOC organic-solvent-free hot water-resistant coating are mixed according to the proportion, dispersed uniformly, sprayed on a substrate that has undergone degreasing and roughening treatment, and wet-coated The film is baked twice at a temperature of 145-155°C for 10±2 minutes and at a temperature of 280-380°C for 10±2 minutes to obtain the high-temperature and corrosion-resistant coating.

A method for preparing a high-temperature-resistant and corrosion-resistant coating. The raw materials of the low-VOC organic-solvent-free hot-water-resistant coating according to claim 1 are mixed and uniformly dispersed according to the proportion, and the coating is sprayed onto the aluminum substrate that has undergone degreasing and roughening treatment. The material is baked at 145-155°C for 10±2min and then cooled to room temperature naturally.

On top of the dried coating, spray a top coat,

The composite coating film is baked twice at 145-155°C for 10±2 minutes and 280-380°C for 10±2 minutes to obtain a high-temperature and corrosion-resistant coating. The coating has more excellent non-stick, self-cleaning and corrosion-resistant properties.

Compared with prior art, the beneficial effect of the present invention is:

1. The heat-resistant and hydrolysis-resistant engineering plastic dispersion liquid of the present invention has expandability, and can evenly introduce functional fillers into micron and submicron engineering plastic particles; it has a more uniform and smaller engineering plastic particle size (0.1～ 2μm); easy to melt in use, high bonding strength of substrate;

2. The low-VOC, organic-solvent-free, hot-water-resistant coating of the present invention does not contain organic solvents, and can still provide excellent paint film performance when the formula structure remains basically unchanged and only organic solvents are removed, greatly reducing the development of new formulas workload:

3. The low-VOC organic solvent-free hot water resistant coating of the present invention has a low film-forming baking temperature (film-forming baking temperature is 280-380°C, 10min);

4. The high-temperature and corrosion-resistant coating obtained by coating the low-VOC organic-solvent-free hot water-resistant coating of the present invention has excellent adhesion.

Description of drawings

Fig. 1 is the particle size detection report that comparative example 1 makes PES dispersion liquid;

Fig. 2 is the SEM photograph that comparative example 1 makes PES dispersion liquid particle;

Fig. 3 is the particle size detection report that comparative example 2 makes PES dispersion liquid;

Fig. 4 is the SEM photograph that comparative example 3 makes PES dispersion liquid particle;

Fig. 5 is the particle size detection report that embodiment 1 makes PPSU dispersion liquid;

Fig. 6 is the SEM photograph that embodiment 1 makes PPSU dispersion liquid particle;

Fig. 7 is the TEM picture of the PPSU dispersion liquid particle that embodiment 1 makes.

Detailed ways

The technical solution of the present invention will be further specifically described below through specific examples. It should be understood that the implementation of the present invention is not limited to the following examples, and any modifications and/or changes made to the present invention will fall within the protection scope of the present invention.

In the present invention, unless otherwise specified, all parts and percentages are in weight units, and the equipment and raw materials used can be purchased from the market or commonly used in the field. The methods in the following examples, unless otherwise specified, are conventional methods in the art.

In the following examples,

The particle size analysis of the dispersed particles of engineering plastics is analyzed and measured by Baxter BT-9300S laser particle size analyzer;

SEM photos of dispersed particles of engineering plastics, measured by Regulus-8230 and SU8000 scanning electron microscopes;

The TEM photo of the dispersed particles of engineering plastics was measured by Talos F200X transmission electron microscope.

PES coarse powder, BASF Co., Ltd., grade E 2020 P, D50≈2mm;

PPSU coarse powder, Guangdong Youju Advanced New Materials Co., Ltd., grade F1550P, D50≈1.5mm;

Nano-boron nitride, Suzhou Napor Material Technology Co., Ltd., brand NS-BN, D50≤500nm.

Test Methods:

The particle size analysis of resin dispersed particles is measured by Baxter BT-9300S laser particle size analyzer;

TEM photo of resin dispersed particles, measured by Talos F200X transmission electron microscope;

Adhesion test, refer to GB/T9286-1998 to draw 1mm hundred grids, and the test results;

Hardness test, referring to GB/T6739, using a pencil hardness tester, the test results;

Salt water resistance test, refer to GB/T32095.3, measured in 5% sodium chloride solution, slightly boiling conditions;

For the non-stick test, refer to GB/T32095.2, and use the non-stick test method of fried eggs to test the results.

Comparative example 1

A preparation method of an engineering plastic dispersion, the specific steps are as follows: configure materials according to the composition listed in Table 1, grind in a constant temperature vertical ball mill at 25°C for 24 hours, and then grind in a horizontal sand mill for 32 hours to obtain PES grinding Dispersions. Detected by a laser particle size analyzer, the particle size D50 of the PES particles in the dispersion is 7 μm, and the D90 is 17 μm.

Table 1

ingredients	weight percentage
PES (coarse powder)	25
N-Methylpyrrolidone	25
water	50
total	100

The particle size test report of the PES dispersion is shown in Figure 1, and the SEM photo of the PES dispersion particles is shown in Figure 2.

Comparative example 2

A preparation method of an engineering plastic dispersion, the specific steps are as follows: the formula is the same as in Example 1, grind in a constant temperature vertical ball mill at 25°C for 36 hours, and then grind in a horizontal sand mill for 72 hours to obtain the PES grinding dispersion. Detected by a laser particle size analyzer, the particle size D50 of the PES particles in the dispersion is 3 μm, and the D90 is 12 μm.

See Figure 3 for the particle size test report of the PES dispersion.

Comparative example 3

A kind of preparation method of engineering plastic dispersion liquid, concrete steps are as follows:

Step 1. Take 200 parts of chloroform, add 6 parts of methanol and 60 parts of PES coarse powder, and stir for 30 minutes until PES is fully dissolved; at the same time, take 5 parts of sodium dodecylbenzenesulfonate and dissolve it in 260 parts of water.

Step 2. Pour the sodium dodecylbenzenesulfonate aqueous solution into the colloid mill, then slowly add the chloroform solution of PES into the colloid mill, and disperse to obtain the emulsified dispersion of the PES solution.

Step 3. Pour the material obtained in step 2 into a three-necked flask equipped with a stirring and condensing device, heat it in a water bath, control the temperature in multiple stages, and control the temperature not to exceed 65°C until no solvent is evaporated, and then heat up to 85°C , and keep the temperature for 30 minutes to obtain a solvent-free PES aqueous dispersion. The material in the flask was taken out for laser particle size analysis, and SEM analysis was performed after drying. The SEM analysis results are shown in Figure 4.

Example 1

A kind of preparation method of engineering plastic dispersion liquid, concrete steps are as follows:

Step 1. Take 200 parts of chloroform, add 4 parts of sodium dodecanoate, 4 parts of sodium myristate, and 60 parts of PES coarse powder, and stir for 30 minutes until PES is fully dissolved. Add chloroform to the obtained solution to adjust the solution viscosity to 200±10Pa.s.

Step 2. Stir at a rotational speed of 500 rpm, and at the same time slowly add 300 parts of water, control the addition of water to complete within 5-10 minutes, and obtain an emulsified dispersion of the PES solution.

Step 3. Set the spray steam temperature to 120°C, the steam flow rate to 100L/min, and the emulsified dispersion liquid flow rate of the PES solution to 100g/min, and quickly remove the chloroform in the dispersion liquid by spray evaporation to obtain a heat-resistant and hydrolysis-resistant PES dispersion liquid .

Take the obtained PES dispersion liquid and use a laser particle size analyzer to detect the material particle size distribution of 0.1-0.8 μm, as shown in Figure 5; use scanning electron microscope (SEM) and transmission electron microscope (TEM) to analyze the obtained PES dispersion liquid dried at 110 °C Powder, obtain photos of PES particles with hollow, spherical or quasi-spherical spatial structure, as shown in Figure 6 and Figure 7.

It can be seen from Fig. 1-Fig. 3 that the engineering plastic dispersion is prepared by the grinding method, the processing cycle is long, the product particle size is large, and the particle size distribution is wide.

It can be seen from Figure 4 that the choice of surfactant combination is unreasonable, and even after a severe emulsification process, the particle size of the prepared engineering plastic dispersion product is still difficult to refine to D50≤1μm, and the particle size distribution is wide. By slowly raising the temperature and evaporating the solvent, the prepared engineering plastic dispersion has a reduced particle shape regularity.

Figure 5-Figure 7 proves that after the technical treatment of the present invention, the obtained engineering plastic dispersion product has spherical and spherical appearance, small particle size, D50<0.4μm, D100≤0.8μm, and has a hollow structure.

Example 2

Step 1. Take 150 parts of chloroform, add 4 parts of sodium dodecanoate, 4 parts of sodium myristate, and 60 parts of PPSU coarse powder, and stir for 30 minutes until PPSU is fully dissolved. Add chloroform to the obtained solution to adjust the solution viscosity to 500±10Pa.s.

Steps 2 and 3 refer to Example 1.

The obtained PPSU dispersion liquid is taken and detected by a laser particle size analyzer, and the particle size distribution of the obtained material is 0.7-10 μm.

Example 3

Step 1. Take 200 parts of chloroform, add 4 parts of sodium octadecanoate, 4 parts of sodium hexadecanoate, and 60 parts of PES coarse powder, and stir for 30 minutes until the PES is fully dissolved. Add chloroform to the obtained solution to adjust the solution viscosity to 200±10Pa.s.

Steps 2 and 3 refer to Example 1.

The obtained PES dispersion liquid is taken and detected by a laser particle size analyzer, and the particle size distribution of the obtained material is 0.5-5 μm.

Example 4

Step 1. Take 150 parts of chloroform, add 6 parts of sodium octadecanoate, 6 parts of sodium hexadecanoate, and 60 parts of coarse PES powder, and stir for 30 minutes until PES is fully dissolved. Add chloroform to the obtained solution to adjust the solution viscosity to 500±10Pa.s.

Steps 2 and 3 refer to Example 1.

The obtained PES dispersion liquid is taken and detected by a laser particle size analyzer, and the particle size distribution of the obtained material is 0.1-3 μm.

Example 5

Step 1. Take 200 parts of chloroform, add 6 parts of sodium dodecanoate, 2 parts of sodium myristate, and 60 parts of PES coarse powder, and stir for 30 minutes until PES is fully dissolved. Add chloroform to the obtained solution to adjust the solution viscosity to 200±10Pa.s.

Steps 2 and 3 refer to Example 1.

The obtained PES dispersion liquid is taken and detected by a laser particle size analyzer, and the particle size distribution of the obtained material is 0.1-1.6 μm.

Example 6

Step 1. Take 200 parts of chloroform, add 2 parts of sodium dodecanoate, 6 parts of sodium myristate, and 60 parts of coarse PES powder, and stir for 30 minutes until PES is fully dissolved. Add chloroform to the obtained solution to adjust the solution viscosity to 200±10Pa.s.

Steps 2 and 3 refer to Example 1.

The obtained PES dispersion liquid is taken and detected by a laser particle size analyzer, and the particle size distribution of the obtained material is 0.1-2.2 μm.

Example 7

A kind of preparation method of engineering plastic dispersion liquid, concrete steps are as follows:

Step 1. Take 200 parts of chloroform, add 4 parts of capric acid, 4 parts of dodecanoic acid, 15 parts of concentrated ammonia water (20wt%), and 60 parts of PES coarse powder, and stir for 30 minutes until PES is fully dissolved. Adjust the viscosity of the solution to 200 Pa.s by post-supplementing chloroform.

Step 2, step 3, with reference to embodiment 1.

The obtained PES dispersion liquid is taken and detected by a laser particle size analyzer, and the particle size distribution of the obtained material is 0.3-1.8 μm.

Example 8

A kind of preparation method of engineering plastic dispersion liquid, concrete steps are as follows:

Step 1. Take 200 parts of chloroform, add 5 parts of nano-boron nitride, 4 parts of sodium octanoate, 4 parts of sodium dodecanoate, stir well, then add 50 parts of PES coarse powder, stir for 30 minutes until PES Fully dissolve. Adjust the viscosity of the solution to 400 Pa.s by post-supplementing chloroform.

Step 2, step 3, refer to Example 1;

The obtained nano-mica/PES composite particle dispersion liquid is taken and detected by a laser particle size analyzer, and the particle size distribution of the obtained material is 0.3-2 μm.

The particle size data of the dispersions of the above comparative examples and examples are shown in Table 2. According to Table 2, it can be known that the grinding process produces engineering plastic dispersions, and the particle size of engineering plastics is on the order of 10 μm, and it is difficult to further refine them. The selection of surfactant severely limits the size of emulsified particles, and the unreasonable evaporation process also affects the shape of particles after solvent removal. The selected surfactant system of the present invention has obvious advantages in the emulsification effect, the emulsified particle size is smaller, and the particle size distribution is narrow. Among them, under the formula and process combination of Example 1, the particle size of the dispersion liquid of special engineering materials can be achieved. All in the submicron size range.

Table 2 Statistical table of engineering plastic dispersion particle size data

experimental coding	Particle size range	experimental coding	Particle size range	experimental coding	Particle size range
Comparative example 1	D90＝28.8μm	Comparative example 2	D90=21.4μm	Comparative example 3	D90=8.0
Example 1	0.1～0.8μm	Example 2	0.7～10μm	Example 3	0.5～5μm
Example 4	0.1～3μm	Example 5	0.1～1.6μm	Example 6	0.1～2.2μm
Example 7	0.3～1.8μm	Example 8	0.3～2μm	the	the

Application example 1-2

In order to compare the coating properties formed after the coatings containing organic solvents and coatings without organic solvents, the PES dispersion obtained in Comparative Example 1 and Example 1 is prepared respectively, and the coatings are formulated according to the coating ingredients listed in Table 3, wherein PTFE, Carbon black pigments, talcum powder, and thickeners are all fed in water-dispersed form when preparing coatings, and the PES described in Table 3 is the solid content.

Table 3 Coating composition (unit: kg)

Application example	1	2
PES (the dispersion that comparative example 1 grinding method makes)	11.5	/
PES (the dispersion that embodiment 1 makes)	/	11.5
NMP(N-Methylpyrrolidone)	11.5	/
PTFE (polytetrafluoroethylene)	15	15
carbon black pigment	1.5	1.5
Talc powder (<5μm)	3	3
leveling agent	1	1
thickener	0.5	0.5
water	margin	margin
total	100	100

Spray the paint prepared from the formula listed in Table 3 onto the degreasing and roughened aluminum substrate, and bake it at 150°C-10min and 380°C-10min to obtain a PES high-temperature-resistant and corrosion-resistant coating; The thickness of the coating was measured by an eddy current thickness gauge to be 20 μm. The coating performance test results are shown in Table 4.

Table 4 Coating performance comparison data

The data in table 4 proves that the prepared engineering plastic dispersion of the present invention, because the engineering plastic particles possess special size and structure, in coating application, can realize the coating that water-based coating does not have organic solvent, but is consistent with the coating that contains organic solvent performance.

Example 9

A low VOC organic solvent-free hot water resistant coating, the coating is made of the following raw materials: PES particles 15%, PTFE 0%, carbon black 1%, graphene oxide 1%, wetting agent 0.5%, acrylic acid Thickener 2%, water balance, the total weight of the above raw materials is 100%. The PES particles are fed in the form of the engineering plastic dispersion prepared in Example 1.

A method for preparing a high-temperature-resistant and corrosion-resistant coating. The raw materials of the above-mentioned low-VOC organic-solvent-free hot-water-resistant coating are mixed according to the proportion, dispersed evenly, and sprayed on a substrate that has been degreased and roughened. The high temperature and corrosion resistant coating is obtained by baking twice at 150°C for 10 minutes and at 340°C for 10 minutes.

Example 10

A low VOC organic solvent-free hot water resistant coating, the coating is made of the following raw materials: PES particles 15%, PTFE 0%, carbon black 1%, graphene 1%, wetting agent 0.5%, acrylic thickening Agent 2%, water balance, the total weight of the above raw materials is 100%. The PES particles are fed in the form of the engineering plastic dispersion prepared in Example 1.

A method for preparing a high-temperature-resistant and corrosion-resistant coating. The raw materials of the above-mentioned low-VOC organic-solvent-free hot-water-resistant coating are mixed according to the proportion, dispersed evenly, and sprayed on a substrate that has been degreased and roughened. The high temperature and corrosion resistant coating is obtained by baking twice at 150°C for 10 minutes and at 340°C for 10 minutes.

The coatings of Examples 9 and 10 were tested for performance, and the results are shown in Table 5.

table 5

project	Thickness/um	Adhesion	Water Adhesion	salt water resistant
Example 9	20	Level 1	Level 1	28 hours
Example 10	20	Level 1	Level 1	21h

Comparative Examples 11-16 and Examples 11-16

A method for preparing a high-temperature-resistant and corrosion-resistant coating, the specific steps are as follows:

1. Mix and disperse the raw materials in Table 6 according to the ratio to obtain the primer coating material,

Spray the undercoat material on the degreased and roughened aluminum substrate, control the sintering temperature within the range of 150-180°C for 5-10 minutes; after the undercoat is formed, cool it down to room temperature naturally.

Get comparative example 2 (remove organic solvent) and embodiment 1 gained PES dispersion liquid and prepare, prepare coating by the coating composition listed in table 5, wherein PTFE, carbon black pigment, silicon carbide, acrylic acid thickener are all when preparing coating. Feed in the form of water dispersion, the PES mentioned in Table 5 is the solid content. Under the condition that the content of PES is guaranteed to be the same, a comparative test is carried out. Comparative Examples 11-16 investigated the performance of the primer layer with different contents of organic solvents, and Examples 11-16 investigated the performance of the primer layer with the PES dispersion obtained in Example 1 of the present invention with additional addition of different contents of organic solvents.

The specific method for removing the organic solvent from the PES dispersion prepared in Comparative Example 2: Take 1000 g of the PES dispersion prepared by the grinding method in Comparative Example 2, put it into a 5 L 3-necked flask, add 3000 g of pure water, and stir for 30 minutes at 60 ° C. , and then perform suction filtration. Take the filter cake and put it into a 5L 3-neck flask, pour 3000g of pure water into it, stir at 60°C for 30min, then carry out suction filtration, and wash the material 3 times, then check the content of N-methylpyrrolidone in the filtrate, if the content exceeds 100ppm , then repeat the washing until the N-methylpyrrolidone content in the filtrate is lower than 100ppm.

2. Then spray the surface coating material on the bottom coating, and sinter in two steps. The first step controls the temperature within the range of 150-180°C for 5-10 minutes, and the second step controls the temperature at 375-380°C. The time is 8-10 minutes.

Components and ratio of top coat (100% by total weight): PTFE 42%, acrylic thickener 3%, pearl powder 0.5%, propylene glycol 2%, surfactant 3%, leveling agent 0.35%, catalyst Dry agent 3%, water balance.

Table 6 Components and ratio of primer (unit: kg)

Table 6 (Continued table) Components and proportions of primer (unit: kg)

The coatings obtained in Comparative Examples 11-16 and Examples 11-16 were tested, and their performances are shown in Table 7 after testing.

Table 7

Conclusion: The data in Table 7 proves that the fine PES dispersion material prepared by the grinding method, in the process of gradually reducing the resin good solvent content, the water-based coating prepared by it shows synchronously weakened coating bond strength, while this The engineering plastic dispersion prepared by the invention, because of the special structure of dispersed particles, can still provide excellent bonding strength when the content of resin good solvent is gradually reduced until it does not contain resin good solvent or other organic solvents.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

The heat-resistant and hydrolysis-resistant engineering plastic dispersion provided by the present invention and its preparation method have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (10)

1. A low-VOC organic solvent-free hot water resistant coating is characterized in that the coating is mainly made of the following raw materials:

   Engineering plastic particles 5-30%,

   PTFE 0～15%,

   Pigment 0.1～2%,

   Functional filler 0.5～5%,

   Functional additives 0.1～5%,

   Water surplus, the total weight of the above-mentioned raw materials is 100%;

   The engineering plastic particles are added in the form of engineering plastic dispersion liquid, which is obtained by emulsification-solvent evaporation method. The engineering plastic particle diameter in the engineering plastic dispersion liquid is 0.1-2 μm, and has a hollow spherical shape. Or a spherical structure; the engineering plastic dispersion is composed of 10-75 wt% of engineering plastic particles, 0.5-10 wt% of surfactant, and the balance is water.
2. The low VOC organic solvent-free hot water resistant coating according to claim 1, characterized in that: said engineering plastic is selected from polyethersulfone, polyphenylenesulfone, polyetherimide, polysulfone, polyaryletherketone , polyaryl ether sulfone ketone or a combination of several; the solvent is a mixture of one or more of dichloromethane, chloroform, dichloroethane, trichloroethane, carbon disulfide, boiling point It is 40-80°C.
3. The low-VOC organic solvent-free hot water resistant coating according to claim 1, characterized in that: the engineering plastic particles in the engineering plastic dispersion are engineering plastics,

   Or containing 0.5-10% of the mass of engineering plastics, one or more of carbon nanotubes (CNT), acidified carbon nanotubes, nano-boron nitride, graphene, graphene oxide, nano-mica, and nano-bentonite modified engineering plastics.
4. The low-VOC organic solvent-free hot water resistant coating according to claim 1, characterized in that: the emulsifying surfactant is an anionic surfactant of A ^- B ⁺ structure, wherein,

   A ^- is an alkyl carboxylate structure with the molecular formula of C _n H _2n-1 O ₂ ^- , wherein the value of n is 8-16;

   B ⁺ is selected from NH ₄ ⁺ , Na ⁺ , K ⁺ .
5. The low-VOC organic solvent-free hot water resistant coating according to claim 1, characterized in that: the engineering plastic particles in the engineering plastic dispersion have a statistical value of particle size D50≤1μm, D100≤2μm; in the engineering plastic dispersion Engineering plastic particles, the average hollow rate is not less than 25%.
6. The low VOC organic solvent-free hot water resistant coating according to claim 1, characterized in that: the functional filler is selected from quartz, barium sulfate, titanium dioxide, chromium dioxide, zinc oxide, iron oxide, aluminum oxide, silicon oxide , zirconia aluminum silicate, aluminum magnesium silicate, silicon carbide, titanium carbide, silicon nitride, titanium nitride, cubic boron nitride, barium sulfate whisker, calcium carbonate whisker, carbon fiber powder, glass fiber powder, quartz fiber Powder, carbon nanotubes, graphene oxide, graphene, basalt fiber, mica, talcum powder, hexagonal boron nitride or graphite or one or a mixture of several.
7. A preparation method of the engineering plastic dispersion liquid of the low-VOC organic solvent-free hot water resistant coating according to claim 1, characterized in that the method comprises the steps:

   S1. Dissolve engineering plastic particles and surfactants in a solvent, and use the solvent to control the viscosity of the system to 50-1000Pa.s;

   S2. Add water to the material obtained in step S1 under stirring at 300-800 rpm to obtain an oil-in-water emulsion;

   S3. The oil-in-water emulsion is evaporated and concentrated to obtain the water-based engineering plastic dispersion.
8. A high temperature and corrosion resistant coating obtained by coating the low VOC organic solvent-free hot water resistant coating according to claim 1.
9. A method for preparing a high-temperature-resistant and corrosion-resistant coating, characterized in that: the raw materials of the low-VOC organic-solvent-free hot-water-resistant coating according to claim 1 are mixed and uniformly dispersed according to the proportion, and sprayed until after degreasing and roughening treatment On the substrate, the wet coating film is baked twice at 145-155°C for 10±2 minutes and 280-380°C for 10±2 minutes to obtain the high-temperature and corrosion-resistant coating.
10. A method for preparing a high-temperature and corrosion-resistant coating, characterized in that: the raw materials of the low-VOC organic-solvent-free hot water-resistant coating according to claim 1 are mixed and uniformly dispersed according to the proportion, and the coating is sprayed until after degreasing and roughening On the treated aluminum substrate, it is baked at 145-155°C for 10±2min and then cooled to room temperature naturally.

    On top of the dry coating, spray a top coat,

    The composite coating film is baked twice at 145-155°C for 10±2 minutes and 280-380°C for 10±2 minutes to obtain a high-temperature and corrosion-resistant coating.

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