CN109266153A - Aqueous anti-graffiti self-cleaning coating of one kind and preparation method thereof - Google Patents

Abstract

The invention belongs to technical field of coatings, and in particular to aqueous anti-graffiti self-cleaning coating of one kind and preparation method thereof, wherein the coating includes aqueous inorganic nano ceramics modified emulsion 35-70%；Pigment 1-20%；Filler 1-30%；Wetting dispersing agent 0.1-0.5%；Defoaming agent 0.1-0.5%；Rheological agent 1-5%；Water surplus；Wherein aqueous inorganic nano ceramics modified emulsion includes hydroxyl acrylic emulsion 10%-70%；Silica solution 20%-70%；Silane 10%-70%；Organosilicon modifier 0.1%-10%；Water surplus.The present invention use sol-gel technology, make it is inorganic nanometer modified and it is organic-silicon-modified it is synchronous progress, be remarkably improved the hardness and wearability of coating, finally obtained coating products weatherability and hydrophobicity are good, hence it is evident that better than traditional self-cleaning coating.

Description

Water-based anti-doodling self-cleaning coating and preparation method thereof

Technical Field

The invention relates to the technical field of coatings, and particularly relates to a water-based anti-doodling self-cleaning coating and a preparation method thereof.

Background

The aluminum plate curtain wall is made of high-strength aluminum alloy plates, and is fixed on the outer surface of a building through the reinforcing ribs and the corner connectors, so that the aluminum plate curtain wall and the outer wall of the building form a firm whole, the outer wall of the building can be protected from being blown by wind and exposed to the sun, the service life of the building is prolonged, the outer wall can be beautified, the flatness of the outer wall is improved, and the aluminum plate curtain wall is wind-resistant and earthquake-resistant. The aluminum plate curtain wall is usually subjected to chromizing treatment and fluorocarbon spraying treatment, has excellent corrosion resistance and weather resistance, can resist acid rain, salt mist and various pollutants, can withstand ultraviolet irradiation for a long time and can keep colorfast, and the service life is long; however, the aluminum plate curtain wall is the outermost layer of the building, the aesthetic feeling of the appearance is one of the factors to be considered, the appearance can be kept clean and beautiful only by frequent cleaning, the traditional fluorocarbon coating is high in cost, and the paint is not easy to be stained with dust although having certain non-adhesiveness, once the dust is deposited, the paint is not easy to be washed away by rainwater, rain marks are easy to leave after long-term use, the paint is required to be manually cleaned, and for high-rise buildings, the cleaning difficulty of the outer wall of the building is high, the great manpower and financial resources are required to be consumed, and the maintenance difficulty is high. The adoption of the coating with self-cleaning performance to replace fluorocarbon coating can reduce the maintenance difficulty, and is one of the hot spots of the current research.

The Chinese invention patent (CN102391736, a self-cleaning coating for building curtain wall aluminum veneer and a preparation method thereof) discloses a self-cleaning coating, which is divided into a bottom coating coated on an aluminum veneer, namely a first component; an intermediate coating, i.e. a second component, applied over the base coating; a topcoat layer applied over the intermediate coating layer, i.e., a third component. Wherein the first component is polyester resin and amino resin as film forming matter, and silicon-titanium or silicon-zirconium type coupling agent is added; the second component is FEVE fluorocarbon resin as film forming matter; the third component is FEVE fluorocarbon resin and organic silicon resin as film forming matter. The coating needs to be sprayed by three layers in the using process, the operation is complex and the consumed time is long, the thickness, the components and the like of each coating can influence the performance of the final coating, the influence factors are many, and the process difficulty is large; the amino resin and the polyester resin can be yellowed and deteriorated after being subjected to ultraviolet irradiation for a long time, so that the appearance of the aluminum plate curtain wall is influenced; meanwhile, the added organic silicon resin is not modified, and although the surface energy of the organic silicon is low, the stain resistance of the first coating can be improved, the unmodified organic silicon resin is easy to run off along with the prolonging of the service time, and the stain resistance of the coating is further reduced.

The Chinese invention patent (CN101363270, architectural ceramic coating plate and preparation method thereof) discloses a ceramic coating layer which can be sprayed on an aluminum plate, which is composed of inorganic resin formed by curing and polycondensation of alumina sol and hydrolyzable siloxane, can be cured by ultrasonic waves, and has better ultraviolet resistance and acid rain resistance compared with fluorocarbon coating. However, the paint has limited self-cleaning capability, and is easy to stain after long-term use, thereby affecting the appearance.

Chinese invention patent (CN107312407, a long-acting self-cleaning coating and its preparation method) discloses a long-acting self-cleaning coating which is prepared by blending and grinding resin, pigment and filler, auxiliary agent (dispersant, defoaming agent), xylene or ethylene glycol monobutyl ether, curing agent, etc., adding leveling agent and polysiloxane, and mixing uniformly, wherein the resin is any one of acrylic resin, fluorocarbon resin, polyester resin, epoxy resin and amino resin.

The Chinese invention patent (CN105885595, a preparation method of a self-cleaning organosilicon modified acrylic resin heat-insulating reflective coating) discloses a coating with self-cleaning performance, firstly, organosilicon monomers and acrylic acid or acrylate monomers are used as raw materials, an emulsifier and water are added, and under the action of an initiator, organosilicon modified acrylic resin emulsion is prepared; mixing nano ATO, nano titanium dioxide and the like according to a certain proportion to prepare a heat-insulating reflective filler; and finally stirring the organic silicon modified acrylic resin emulsion, the heat insulation reflective filler, the dispersing agent, the defoaming agent and the like at a high speed to obtain the organic silicon modified acrylic resin heat insulation reflective coating with the self-cleaning property. However, the method only adopts organic silicon to modify the acrylic emulsion, so that the crosslinking density of the product is low, fine stains can easily penetrate into a paint film, and the paint film cannot be cleaned; meanwhile, the coating film has low hardness and poor surface wear resistance, and the self-cleaning effect of the coating film surface is greatly reduced after the coating film is worn by wind and sand; and the weather resistance is poor, and the self-cleaning effect is gradually lost after the sun and rain are exposed for a long time.

Disclosure of Invention

The invention aims to solve the technical problems that the existing self-cleaning coating is poor in weather resistance and self-cleaning capability, complex in manufacturing process and the like.

In order to solve the technical problems, the invention discloses a water-based anti-doodling self-cleaning coating which comprises the following components in parts by weight:

because the water-based inorganic nano ceramic modified emulsion is the main effective component of the coating product, the content of the emulsion has the greatest influence on the performance of the coating product, and the weight percentage of the emulsion is preferably 50-60%.

Further, the aqueous inorganic nano ceramic modified emulsion comprises the following components in parts by weight:

according to the invention, organic silicon and inorganic silicon are compounded for modification, so that the final performance of a coating product is determined by the use amount of the inorganic silicon (including silane and silica sol), and the weight percentage of the silica sol is preferably 35-60%; the silane is preferably 30% -50%; the preferred organosilicon modifier is 1-6%.

Further, the aqueous inorganic nano-ceramic modified emulsion also comprises a surfactant, and the weight part of the surfactant is 0.01-10%; the surfactant is preferably an anionic surfactant, for example, octadecyl trimethyl ammonium chloride.

Further, the silica sol comprises one or a mixture of two of acid silica sol and alkaline silica sol; the particle size of the silica sol is 1-160nm, and the pH value is 2-10. The silica sol here is a dispersion of nano-sized silica particles in water, and the dispersion contains a large amount of hydroxyl groups.

Further, the silane is alkoxy silane, and is selected from one or more of methyltrimethoxy silane, methyltriethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, gamma-methacryloxypropyl trimethoxy silane, 3-glycidoxypropyltrimethoxy silane, and dimethyldimethoxy silane.

Further, the organic silicon modifier is a mixture of hydroxyl functional group organic silicon prepolymer and amino functional group organic silicon prepolymer; wherein the weight ratio of the hydroxyl functional group organic silicon prepolymer to the amino functional group organic silicon prepolymer is 1:0.25-3, and further 1: 0.6-1.5. The hydroxyl functional group organic silicon prepolymer and the amino functional group organic silicon prepolymer are compounded for use, the hydroxyl functional group organic silicon prepolymer can be dehydrated and copolymerized with silanol groups of the inorganic nano silicon dioxide, but the self-polycondensation trend of the hydroxyl functional group organic silicon prepolymer is low, and the silanol groups of the inorganic nano silicon dioxide have strong self-polycondensation trend, so that when dehydration and copolycondensation are caused, one part of the silanol groups of the inorganic nano silicon dioxide and the hydroxyl functional group organic silicon prepolymer are subjected to copolycondensation, and the other part of the silanol groups of the inorganic nano silicon dioxide and the hydroxyl functional group organic silicon prepolymer are subjected to self-polycondensation, so that the crosslinking density is low, the coating film density is poor, and the stain-resistant and anti-. By adding the amino-functional group organic silicon prepolymer and the hydroxyl-functional group organic silicon prepolymer for compounding, the curing and crosslinking characteristics of the amino-functional group organic silicon prepolymer to the organic silicon prepolymer promote the silanol hydroxyl groups of the hydroxyl-functional group organic silicon prepolymer and the inorganic nano silicon dioxide to be synchronously copolycondensed, so that the crosslinking density is improved, the uniform coating compactness is realized, and the anti-graffiti performance of the coating is greatly improved; meanwhile, different crosslinking densities of the final coating film can be controlled by different addition amounts of the amino functional group organic silicon prepolymer.

Further, the hydroxyl functional group organic silicon prepolymer is a mixture of low-hydroxyl silicone oil with the hydroxyl content less than or equal to 4% and medium-high hydroxyl silicone oil with the hydroxyl content greater than 4%; wherein the weight ratio of the low hydroxyl content hydroxyl silicone oil to the medium high hydroxyl content hydroxyl silicone oil is 1:1-4, and further 1: 1.5-3. For hydroxyl silicone oil, the content of hydroxyl determines the reactivity of the hydroxyl silicone oil, and the higher the content of hydroxyl is, the higher the reactivity is, and the more obvious the modification effect is; the organic silicon prepolymer with medium and high hydroxyl content and low hydroxyl content is used in a compounding way, the organic silicon prepolymer with medium and high hydroxyl content and hydroxyl functional group has higher crosslinking activity and compatibility, but the slip is lower than that of the organic silicon prepolymer with low hydroxyl content and hydroxyl functional group; the low-hydroxyl-content hydroxyl functional group organic silicon prepolymer has relatively low crosslinking activity and compatibility; therefore, by compounding the hydroxyl functional group organic silicon prepolymer with low hydroxyl content and medium and high hydroxyl content, the anti-stain and anti-graffiti performance can be obtained, the high-slip surface can be obtained, and the anti-graffiti self-cleaning performance of the coating film can be further improved.

For example, the silicone modifier may be selected from Srocco, Guangzhou3300、8865H and8805, and mixtures thereof. Wherein,3300 is a cross-linked organic modified polydimethylsiloxane, which is an organosilicon polymer with bifunctional group and high reactivity, and has amino functional group, and can impart excellent soft and moist feeling, anti-sticking property, and high-temperature release and demolding property to the surface of the coating;8865H is an organosilicon oligomer with a dihydroxyl functional group, has a hydroxyl content of 8%, has high reactivity similar to that of polyhydric alcohol, can endow resin with excellent hand feeling, and can improve wear resistance, prevent adhesion, prevent fouling and resist graffiti.8805 is a silicone oligomer with monohydroxy functional group, has hydroxyl content of 3%, has certain reactivity, and can endow resin with smooth hand feeling, and prevent adhesion and sticking.

Further, the pigment is one or more of titanium dioxide, pearlescent pigment, fluorescent pigment and metal pigment.

Further, the filler is one or more of calcium sulfate whisker, crystal whisker silicon, talcum powder, kaolin and mica powder.

Wetting and dispersing are important technological processes for preparing the coating, and selecting a proper wetting dispersant according to needs is an important link for determining whether the coating can be prepared successfully. Since the coating obtained according to the invention is an aqueous coating, an aqueous wetting dispersant should be selected here. The aqueous wetting dispersant can reduce the surface tension of an aqueous solution, promote the wettability of the pigment, and ensure that the wetting dispersant is easy to spread on the surface of the pigment for combination to form an anchoring relation;meanwhile, the surface tension is reduced, the construction performance of the coating can be improved, and the defect of poor leveling of the coating is overcome. In the present invention, the chemistry of Guangzhou siloco is selected8008 the product, namely polyether modified polysiloxane, is an organosilicon super wetting agent with a silicon-carbon structure, is colorless transparent liquid, has extremely low surface tension, is weak acid and weak base resistant, is in a stable state under the condition that the pH is 3-12, can almost wet all surfaces of low surface energy materials such as metal and plastic, and has low temperature foamability.

Foam is inevitably generated in the stirring process of the emulsion, and the foam is a thermodynamically unstable system, is very easy to break and has influence on the performance of the emulsion, so the defoaming process in the preparation process of the water-based paint is also very important. According to the invention, BYK-015 is selected as a class of polymer defoaming agent, and the polymer defoaming agent does not contain organic silicon and mineral oil, and has good anti-foaming performance.

The rheological agent is also a key component of the water-based paint, can control the fluidity of a fluid product, can prevent the paint from dripping and splashing in the process of rolling or brushing, and improves the sagging resistance of the paint; the paint can also prevent the sedimentation of the pigment during the transportation process of the paint, and ensure the uniformity of the product. According to the invention, BYK-420 which is a modified urea solution is selected and added into a system to form a three-dimensional network structure, so that thixotropic flow property can be generated, sedimentation is prevented, sagging resistance is improved, good dispersion of the pigment can be ensured in a pigment stabilizing stage, and optimal construction performance is obtained.

Further, the preparation method of the aqueous inorganic nano ceramic modified emulsion comprises the following steps:

(1) uniformly mixing silane, an organic silicon modifier and a surfactant to form a semitransparent silane mixed solution, namely a solution I;

(2) adding silica sol and water into the hydroxyl acrylic emulsion, and stirring for 5-30min to obtain a solution II;

(3) dropwise adding the solution I into the solution II within 30 min;

(4) heating, keeping the reaction temperature at 35-75 ℃, and reacting for 0.5-2h at constant temperature;

(5) adding water, stopping heating, and naturally cooling to obtain milky semitransparent or opaque liquid, namely the aqueous inorganic nano ceramic modified emulsion.

The hydroxyl acrylic emulsion is used as a base material, contains a large amount of active hydroxyl, and can react with an organic silicon modifier containing a large amount of active alkoxy and alkoxy silane to obtain modified acrylic acid and modified acrylic emulsion with good physical and chemical properties; the modified organic silicon and the inorganic silicon (including silane and silica sol) are adopted in the invention, the modified organic silicon can further improve the performance of the acrylic emulsion, the organic silicon and the inorganic silicon jointly treat the hydroxyl acrylic emulsion, and the sol-gel process is adopted to synchronously modify the inorganic silicon and the organic silicon, so that the aqueous inorganic nano-ceramic modified emulsion is endowed with higher crosslinking density and hardness and has extremely strong weather resistance and wear resistance of inorganic nano-materials; the self-cleaning effect of the final product comes from the hydrophobic properties of the organic silicon and the silane on one hand, and also has the improvement of the self-cleaning property brought by the organic silicon modification treatment process, so that the self-cleaning effect and the long-acting self-cleaning effect of the product are obviously improved compared with the traditional product.

The invention also discloses a preparation method of the water-based anti-doodling self-cleaning coating, which comprises the following steps:

① mixing the water inorganic nano ceramic modified emulsion with pigment and filler, and dispersing with wetting dispersant for 10-30min to obtain dispersion;

②, grinding the dispersion liquid by a horizontal sand mill, and simultaneously adjusting the temperature of cooling water to ensure that the temperature of the ground material is less than or equal to 60 ℃ and the grinding time is 1-2 h;

③ adding defoaming agent, rheological agent and water, stirring uniformly to obtain the water-based anti-graffiti self-cleaning coating.

In the invention, the wetting dispersant firstly wets pigment particles and filler, then is ground by a grinding machine to form a semi-flocculent dispersoid, and then is mixed with the defoaming agent, the rheological agent and the like to obtain a stable dispersion system of the pigment and the filler, and the pigment has good color development, high vividness and good gloss.

Compared with the prior art, the water-based anti-doodling self-cleaning coating and the preparation method thereof have the following advantages:

1. the coating film has good hydrophobicity and higher self-cleaning property.

2. The weather resistance is strong, and the self-cleaning effect can be kept well after long-term exposure to the sun and rain.

3. The coating has high hardness, strong wear resistance and strong scratch resistance.

4. The bonding strength of the coating film and the aluminum plate curtain wall is high, and the coating film is not easy to fall off.

5. Has good wiping resistance and is easy to wipe.

6. The preparation process of the coating is simple, complex mechanical equipment is not needed, and the production cost can be reduced.

The specific implementation mode is as follows:

the technical solution of the present invention will be described in detail by the following specific examples.

A water-based anti-doodling self-cleaning coating and a preparation process thereof comprise the following steps:

firstly, preparing aqueous inorganic nano ceramic modified emulsion:

(1) uniformly mixing silane, an organic silicon modifier and a surfactant according to a certain ratio to form a semitransparent silane mixed solution, namely a solution I;

(2) adding silica sol and water into a weighed hydroxyl acrylic emulsion in advance, and stirring for 30min to obtain a solution II;

(3) dropwise adding the solution I into the solution II within 30 min;

(4) heating, keeping the reaction temperature at 55 ℃, and reacting for 2 hours at constant temperature;

(5) adding the rest amount of water, stopping heating, and naturally cooling to obtain milky semitransparent or opaque liquid, namely the aqueous inorganic nano ceramic modified emulsion.

By the same preparation method, 7 groups of emulsion products are prepared, which are respectively marked as T1-T7, and the raw materials and the mixture ratio of each group of emulsion products are shown in the following table 1.

Secondly, preparing the water-based anti-doodling self-cleaning coating:

① mixing the prepared aqueous inorganic nano-ceramic modified emulsion, pigment and filler, and dispersing with wetting dispersant for 25min to obtain dispersion;

② grinding with a horizontal sand mill, and adjusting the temperature of cooling water to ensure the temperature of the ground material is 50 deg.C and the grinding time is 1.5 h;

③ adding defoaming agent, rheological agent and water, stirring uniformly to obtain the water-based anti-graffiti self-cleaning coating.

The same preparation method is adopted to prepare 9 groups of waterborne doodling-resistant self-cleaning coatings which are respectively marked as S1-S9, wherein the waterborne inorganic nano ceramic modified emulsion used by S1, S2 and S3 is T1, and the difference is that the dosage of emulsion products is different; the water-based inorganic nano ceramic modified emulsion used in S4-S9 is T2-T7 respectively, and the raw materials and the mixture ratio of each group of coating products are shown in Table 2 below.

TABLE 1 ratio of raw materials in aqueous inorganic nano-ceramic modified emulsion

TABLE 2 proportioning of the raw materials in the aqueous anti-graffiti self-cleaning coating

It is worth mentioning that the invention also carries out supplementary experiments, and finds that: for the silica sol, no matter single acidic silica sol or alkaline silica sol is selected, or a mixture of the acidic silica sol and the alkaline silica sol is selected, as long as the total consumption, namely the weight percentage, of the silica sol is the same, the selected silica sol does not influence the performance of the coating product. Similarly, a variety of optional silane, pigment, and filler types are given above, and the type of each component does not affect the performance of different coating products, which changes only when the components are used in different amounts. Thus, in the examples, a single type or a mixture of types of silica sol, silane, pigment or filler is used as each component, and it is considered that the component is not changed between different coating products as long as the amount is the same. Meanwhile, for raw materials not listed, for example: wetting dispersants, defoamers, rheology agents, surfactants, etc., although the above examples do not list other alternatives, and do not represent that only a single alternative is used, that other component classes can be used to achieve the corresponding effect, and that likewise only the total amount of components used will have an effect on the performance of the coating product, while the choice of different classes is considered to have no change in that component.

Comparative example 1

Mixing the components A: 75 wt% of water, 25 wt% of alumina sol, and a component B: 30 wt% of tetraethoxysilane, 20 wt% of methyltrimethoxysilane and 50 wt% of isopropanol, mechanically stirring according to the proportion of 1:1, and performing rolling or ultrasonic curing treatment to obtain the ceramic coating. Denoted B1.

Comparative example 2

Adding 49 parts of acrylic resin into a charging basket, stirring, slowly adding 15 parts of rutile titanium dioxide, 0.5 part of BYK-110 dispersant and 0.5 part of BYK-066N defoamer, uniformly mixing, and grinding the mixed solution; and then, adding 0.3 part of BYK-310 leveling agent, 6 parts of polysiloxane, 15 parts of xylene, 3.7 parts of propylene glycol monomethyl ether acetate, 10 parts of butyl acetate and 5 parts of HDI curing agent, and uniformly mixing again to obtain the long-acting self-cleaning ceramic coating. Denoted B2.

Comparative example 3

(1) Adding 12g of vinyltriethoxysilane, 35g of acrylic acid, 3.2g of potassium persulfate, 30g of water, 5gOP-10 (polyoxyethylene octylphenol ether-10) and 2g of sodium dodecyl sulfate into a three-neck flask, stirring and emulsifying for 45min under the condition of ice-water bath, then heating to 75 ℃, preserving heat, stirring and reacting for 4.5h, cooling to room temperature, adjusting the pH value to be neutral by ammonia water, filtering, and discharging to obtain the organosilicon modified acrylic resin emulsion;

(2) 100g of nano ATO powder, 15g of nano titanium dioxide powder, 20g of hollow glass beads and 0.5g of ultraviolet absorbent UV329 are weighed in sequence and poured into a high-speed stirrer to be stirred for 10min, and the heat-insulating reflective filler is obtained.

(3) Weighing 100g of organic silicon modified acrylic resin emulsion, 20g of heat insulation reflective filler, 2g of sodium hexametaphosphate, 0.7g of polyether modified silicone oil and 0.5g of dodecyl alcohol ester in sequence, adding into a high-speed stirrer, and stirring for 35min to obtain the self-cleaning organic silicon modified acrylic resin heat insulation reflective coating. Denoted B3.

To characterize the water contact angle and wiping properties of the coating products examples S1-S9 and comparative examples B1-B3, coating films were prepared by spraying the coatings on aluminum panels as follows: firstly, cleaning and degreasing an aluminum plate, and carrying out sand blasting to obtain a surface with the roughness of 2-10 mu m; and then, spraying the coating on the surface of the treated aluminum plate by adopting an air spraying method, leveling the coating, placing the leveling coating into an oven, and baking for 10min at the temperature of 200 ℃, thereby finally obtaining a ceramic coating film with the thickness of 20 microns on the aluminum plate.

The following performance tests were performed on the 12 groups of products:

1. adhesion of coating

The paint products S1-S9 and B1-B3 were tested for adhesion with reference to the national standard GB/T9286-1998 test for marking test of paint and varnish films.

2. RCA paper tape abrasion resistance test

The abrasion Resistance of the above-described coating products S1-S9 and B1-B3 was tested Using an RCA tape abrasion tester, with reference to the American Standard ASTM F2357-2010 Standard Test Method for Determining the abrasion Resistance of Inks and Coatings on Membrane Switches Using the Norman Tool RCA "Abrader".

3、QUV

The paint products S1-S9 and B1-B3 were tested for their resistance to ageing by reference to the national standard GB/T23987-2009-Artificial weathering Exposure to fluorescent UV and Water for pigmented and clear coatings-the time required for the paint to continue to be exposed until a gloss retention of > 70% is achieved.

4. Hardness of

The paint products S1-S9 and B1-B3 are subjected to hardness tests by referring to the national standard GB/T6739-2006 paint film hardness determination by the color paint and varnish pencil method.

5. Water contact angle

The water contact angles of the coatings S1-S9 and B1-B3 sprayed on the aluminum panels were tested using a water contact angle tester to characterize the hydrophobic properties of the coatings.

6. Wiping test

Paints S1-S9 and B1-B3 sprayed on aluminum plates were written with a graffiti pen, wiped, and their wiping performance was tested.

The performance results for paint products S1-S9 and B1-B3, by the above tests, are shown in Table 3 below.

TABLE 3 Performance test results for paint products S1-S9 and B1-B3

As shown in Table 3 above, the overall performance of the coating products S1-S9 in the examples was superior to the products B1-B3 in the comparative examples. The performance of the coating obtained by compounding the organic silicon and the inorganic silicon is better.

As for the water contact angle, the contact angles of S1-S9 are all larger than 100 degrees, the water repellency is good, when the paint is used for an aluminum plate curtain wall, the paint can be washed by rainwater without residue, dust is not easy to adhere to the surface of the paint, and the paint shows excellent hydrophobic self-cleaning performance. And the hydrophobicity of B1-B3 is not obvious, so that the paint is easy to be stained with dust, and the self-cleaning effect is poor.

QUV test results show that S1-S9 can be subjected to ultraviolet continuous irradiation for more than 3000 hours, the gloss retention rate is still more than 70%, and comparative examples B1-B3 are only about 2000 hours, which shows that the coating product of the invention has good ultraviolet resistance, strong weather resistance, can be stably used for a long time and keeps better performance.

The hardness of S1-S9 and the wear-resisting times of the RCA paper tape are both greater than those of B1-B3, which shows that the coating prepared by the method has higher hardness and stronger wear resistance, can effectively resist scraping and still has good appearance after long-term use.

And the adhesive force of S1-S9 is strong, and the coating is not easy to fall off once being sprayed on a base material, so that the service life of the coating is prolonged.

After S1-S9 and B1-B3 are sprayed on an aluminum plate, a graffiti pen is used for writing on a coating film, and then wiping is carried out, so that the S1-S7 coating film is easy to wipe off and has no residue or a little residue, while the B1-B3 coating film is difficult to wipe off and has ink residue.

Compared with the preparation processes of the S1-S9 paint products and the B1-B3 paint products, the preparation method of the paint is simple, complex mechanical equipment is not needed, additional equipment is not needed, and the production cost is greatly reduced.

For examples S1-S9, it can be seen from the test results in Table 3 above that the performance of S1 is the best example. S1, S2 and S3 use the same aqueous inorganic nano ceramic modified emulsion, all T1, the difference is only that the dosage of the aqueous inorganic nano ceramic modified emulsion is different, compared with S1, the dosage of the emulsion in S2 is less, and the adhesive force, the wear resistance and the hardness are slightly reduced; the dosage of the emulsion in S3 is too much, so that the wear resistance is reduced; it shows that the dosage of the aqueous inorganic nano ceramic modified emulsion has certain influence on the performance of the final coating product.

The aqueous inorganic nanoceramic modified emulsions with the numbers T2-T7 are respectively used in the S4-S9, and the use amount of the emulsions is the same, so that the overall performance is reduced compared with S1-S3 using the T1 emulsion, because compared with the T1: (1) for T2, the use of a small amount of inorganic silicon resulted in ineffective modification of the hydroxyacrylic emulsion by both inorganic silicon and silicone, and the use of a small amount of silicon resulted in a decrease in the hydrophobicity of the S4 coating film and a slight residue of graffiti wiping. (2) For T3, the use amount of inorganic silicon is too large, and similarly, the ratio of organic silicon to inorganic silicon is not suitable, so that the crosslinking density is low, the glossiness of the coating under ultraviolet irradiation is more easily damaged, and the wear resistance is also reduced; however, the inorganic silicon has high hardness, so that the hardness of the coating film S5 is high; the silicon is used in a large amount, and the hydrophobicity and the graffiti wiping performance are still good. (3) In T4, the amount of silicone used was too small to achieve the optimum effect of modifying silicone and inorganic silicon, as in T2, and the hydrophobicity and graffiti wiping performance of the S6 coating film were also reduced. (4) For T5, the dosage of the organosilicon is more, the modification effect is poorer, the crosslinking density is low, and the QUV performance, the abrasion resistance and the hardness are poorer, but the hydrophobicity of the S7 product is better due to the high hydrophobicity of the organosilicon, the water contact angle is larger, and the wiping performance is also good. (5) For T6, the proportion of amino functional group organosilicon prepolymer is high, which easily causes excessive polycondensation of organosilicon and inorganic silicon, causes excessive crosslinking density, and reduces the overall performance of the product, especially the adhesive force with an aluminum plate; however, the crosslinking density is large, and the hardness of the coating film S8 is not reduced. (6) For T7, the proportion of the hydroxyl functional group organic silicon prepolymer with medium and high hydroxyl content is high, and the overall performance of the product is reduced; the hydroxyl functional group organic silicon prepolymer with medium and high hydroxyl content has high activity but poor smoothness, so that the wiping performance of an S9 coating product is reduced, and a small amount of residue exists after wiping.

From the analysis of the products S4-S9 in the above examples, the ratio of the organic silicon to the inorganic silicon, the ratio of the hydroxyl functional group-amino functional group organic silicon prepolymer, and the ratio of the hydroxyl functional group organic silicon prepolymer with low hydroxyl content and medium and high hydroxyl content all affect the crosslinking modification of the products, and further affect the comprehensive performance of the products; however, because the inorganic silicon and the organic silicon in the coating product are modified together, the product performance under all raw material proportions is still better than that of the coating product which is modified by only adopting the organic silicon or the inorganic silicon in the comparative examples B1-B3.

Therefore, the usage of the aqueous inorganic nano ceramic modified emulsion, the usage of organic silicon and inorganic silicon and the like can influence the performance of the coating product, but the latter mainly influences the chemical modification crosslinking degree of silicon, so that the performance of the coating is influenced more.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the design concept of the present invention should be included in the scope of the present invention.

Claims (10)

1. The water-based anti-doodling self-cleaning coating is characterized by comprising the following components in parts by weight:

。

2. the aqueous graffiti-resistant self-cleaning coating of claim 1, wherein: the aqueous inorganic nano ceramic modified emulsion comprises the following components in parts by weight:

3. the aqueous graffiti-resistant self-cleaning coating material of claim 2, wherein: the aqueous inorganic nano ceramic modified emulsion also comprises a surfactant, and the weight part of the surfactant is 0.01-10%.

4. The aqueous graffiti-resistant self-cleaning coating material of claim 3, wherein: the preparation method of the aqueous inorganic nano ceramic modified emulsion comprises the following steps:

(1) uniformly mixing silane, an organic silicon modifier and a surfactant to form a semitransparent silane mixed solution, namely a solution I;

(2) adding silica sol and water into the hydroxyl acrylic emulsion, and uniformly stirring to obtain a solution II;

(3) dropwise adding the solution I into the solution II;

(4) heating and keeping constant temperature reaction;

(5) adding water, stopping heating, and naturally cooling to obtain milky semitransparent or opaque liquid, namely the aqueous inorganic nano ceramic modified emulsion.

5. The aqueous graffiti-resistant self-cleaning coating material of claim 2, wherein: the silica sol comprises one or a mixture of two of acid silica sol and alkaline silica sol; the particle size of the silica sol is 1-160nm, and the pH value is 2-10.

6. The aqueous graffiti-resistant self-cleaning coating material of claim 2, wherein: the silane is alkoxy silane and is selected from one or more of methyltrimethoxy silane, methyltriethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, gamma-methacryloxypropyl trimethoxy silane, 3-glycidyl ether oxypropyl trimethoxy silane and dimethyl dimethoxy silane.

7. The aqueous graffiti-resistant self-cleaning coating material of claim 2, wherein: the organic silicon modifier is a mixture of hydroxyl functional group organic silicon prepolymer and amino functional group organic silicon prepolymer; wherein the weight ratio of the hydroxyl functional group organic silicon prepolymer to the amino functional group organic silicon prepolymer is 1: 0.25-3.

8. The aqueous graffiti-resistant self-cleaning coating of claim 7, wherein: the hydroxyl functional group organic silicon prepolymer is a mixture of low-hydroxyl silicone oil with the hydroxyl content less than or equal to 4% and medium-high hydroxyl silicone oil with the hydroxyl content greater than 4%; wherein the weight ratio of the low hydroxyl content hydroxyl silicone oil to the medium high hydroxyl content hydroxyl silicone oil is 1: 1-4.

9. The aqueous graffiti-resistant self-cleaning coating of claim 1, wherein: the pigment is one or more of titanium dioxide, pearlescent pigment, fluorescent pigment and metal pigment; the filler is one or more of calcium sulfate whisker, crystal whisker silicon, talcum powder, kaolin and mica powder.

10. A process for the preparation of an aqueous graffiti-resistant self-cleaning coating material according to any one of claims 1 to 9, comprising the steps of:

① mixing the water inorganic nano ceramic modified emulsion with pigment and filler, and dispersing with wetting dispersant to obtain dispersion;

②, grinding the dispersion liquid, and adjusting the temperature of cooling water at the same time to ensure that the temperature of the ground material is less than or equal to 60 ℃;

③ adding defoaming agent, rheological agent and water, stirring uniformly to obtain the water-based anti-graffiti self-cleaning coating.