CN111040486B

CN111040486B - Hydrophilic easy-to-clean coating and preparation method and application thereof

Info

Publication number: CN111040486B
Application number: CN201911370253.7A
Authority: CN
Inventors: 雷健
Original assignee: Hefei Hualing Co Ltd; Midea Group Co Ltd; Hefei Midea Refrigerator Co Ltd
Current assignee: Hefei Hualing Co Ltd; Midea Group Co Ltd; Hefei Midea Refrigerator Co Ltd
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2021-04-09
Anticipated expiration: 2039-12-26
Also published as: CN111040486A

Abstract

The invention relates to a hydrophilic easy-to-clean coating and a preparation method and application thereof. The hydrophilic easy-cleaning coating comprises the following components in parts by weight: 18-24 parts of potassium silicate, 55-61 parts of silicic acid dispersoid, 0.36-0.56 part of silane coupling agent and 17-23 parts of water; wherein the modulus of the potassium silicate is 3.6-4.0; the silicic acid dispersion is a mixture of lithium silicate and sodium silicate, and the modulus of the silicic acid dispersion is 2.4-3.0. The preparation method of the hydrophilic easy-cleaning coating comprises the steps of mixing a silicic acid dispersoid and a silane coupling agent to obtain a mixed solution; then adding water and potassium silicate into the mixed solution and stirring uniformly. The hydrophilic easy-cleaning coating can be used as a coating applied to materials such as metal, glass and the like, and has the advantages of easy cleaning, good adhesion, high hardness, good flexibility, high impact resistance, acid and alkali resistance, high and low temperature resistance, salt mist resistance, high temperature and humidity resistance, durability and the like; and the components are simple, the quality control is easy, and the cost is low.

Description

Hydrophilic easy-to-clean coating and preparation method and application thereof

Technical Field

The invention relates to the field of coatings, in particular to a hydrophilic easy-to-clean coating and a preparation method and application thereof.

Background

With the improvement of living standard, people have higher and higher requirements on kitchen household appliances. The kitchen electrical appliance needs to be contacted with substances such as oil smoke, seasonings, food and the like for a long time, and has the problems of easy oil contamination, easy bacteria breeding and the like. Because the surface of the material contacting the oil stain is mostly made of metal material, the material has large adhesion with the oil stain, and the stain is not easy to remove; however, the use of chemical agents such as detergents can corrode the surface of the material, reducing the life of the material.

In the prior art, the coating is added on the surface of the material to make up the defects of the material, such as polytetrafluoroethylene (Teflon), and oil stains are difficult to adhere to the surface of the material due to the low surface energy of the polytetrafluoroethylene (Teflon), so that the aim of easy cleaning is fulfilled. Therefore, the method has important significance in finding an easy-to-clean coating which is simple and convenient to operate, low in cost, good in durability and excellent in performance.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the hydrophilic easy-to-clean coating provided by the invention has high transparency, can improve the glossiness of the coating when attached to the surface of a material, is not easy to crack, is easy to clean, has good adhesive force and high hardness, and improves the performance of the material and the experience of a user to a great extent.

The invention also provides a preparation method of the hydrophilic easy-cleaning coating.

The invention also provides an application method of the hydrophilic cleaning coating and a product containing the hydrophilic cleaning coating, such as a refrigerator.

Specifically, the technical scheme adopted by the invention is as follows:

in one aspect of the invention, a hydrophilic easy-cleaning coating is provided, which comprises the following components in parts by weight: 55-61 parts of silicic acid dispersoid, 18-24 parts of potassium silicate, 0.36-0.56 part of silane coupling agent and 17-23 parts of water; wherein the modulus of the potassium silicate is 3.6-4.0; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the silicic acid dispersoid is 2.4-3.0.

In some embodiments, the silicic acid dispersion is 57 to 60 parts; preferably, the silicic acid dispersion is 58.09 parts.

In some embodiments, the potassium silicate is 20 to 22 parts; preferably, the potassium silicate is 21.27 parts.

In some embodiments, the silane coupling agent is 0.4 to 0.5 parts; preferably, the silane coupling agent is 0.46 parts.

In some embodiments, the water is 18-21 parts; preferably, the water is 19.9 parts.

In some embodiments, the potassium silicate has a modulus of 3.7 to 3.9; preferably, the potassium silicate has a modulus of 3.8.

In some embodiments, the silicic acid dispersion modulus is 2.6 to 2.8; preferably, the silicic acid dispersion has a modulus of 2.7.

The coating formula of the invention belongs to a water glass system, and the structural formula of the coating is M₂O·nSiO₂·mH₂O, where M is K, Na, Li or other alkali metal, and n is the modulus, i.e. SiO₂/M₂The molar ratio of O, and m is the molecular number of crystal water; generally, as the modulus increases, the binding ability, binding strength and water resistance of the silicate may be improved, but the stability and film forming property of the coating may be deteriorated; the inventor researches and discovers that the ratio of potassium to sodium to lithium has great influence on the water resistance, acid and alkali resistance and other properties of the coating. By adjusting the modulus and the proportion of each substance in silicate in a water glass system, the easy-to-clean coating with good comprehensive performance can be prepared.

In some embodiments, the silane coupling agent is selected from at least one of aminopropyltriethoxysilane, mercaptopropyltrimethoxysilane, pentafluorophenyldimethylchlorosilane, 3- (2, 3-glycidoxy) propyltrimethoxysilane, ethoxydimethyl [3- (oxiranoxy) propyl ] silane, trimethoxy [3- (oxiranylmethoxy) propyl ] silane.

In some embodiments, the hydrophilic easy-cleaning coating further comprises 0.2-0.4 part by weight of an auxiliary agent. Preferably, the auxiliary agent is selected from at least one of a wetting agent and a leveling agent.

In some embodiments, the hydrophilic easy-cleaning coating further comprises 0.1-0.2 part by weight of a wetting agent.

In some embodiments, the hydrophilic easy-to-clean coating further comprises 0.1-0.2 part by weight of a leveling agent.

In some embodiments, the wetting agent is selected from at least one of an aqueous acrylate copolymer solution, a polyether modified silicone.

In some embodiments, the leveling agent is selected from at least one of a silicone hexaacrylate copolymer, a modified acrylic leveling agent, a silicone leveling agent.

The auxiliary agent used in the invention is mainly used for improving the processing performance, plays an auxiliary role, and has little influence on the performance of the coating, such as easy cleaning and the like. The types of the auxiliary agents can be added or deleted according to actual requirements.

The invention also provides a preparation method of the hydrophilic easy-cleaning coating, which comprises the following steps:

1) mixing the silicic acid dispersoid with a silane coupling agent to obtain a mixed solution;

2) and adding the rest components into the mixed solution, and uniformly stirring to obtain the hydrophilic easy-to-clean coating.

In some embodiments, step 1) is to add the silane coupling agent to the silicic acid dispersion under stirring, and stir until the solution is clear, to obtain a mixed solution.

In some embodiments, the step 1) is specifically to add the silane coupling agent into the silicic acid dispersion under a stirring state of 100-150 rpm, continue stirring until the solution is clear, and stir for 10-15 min to obtain a mixed solution.

In some embodiments, the step 2) is specifically to add water into the mixed solution and stir for 10-15 min, and then add potassium silicate and stir for 10-15 min, so as to obtain the hydrophilic easy-to-clean coating.

In some embodiments, the step 2) is to drop the auxiliary agent into the mixed solution and stir the mixture evenly, and then add water and potassium silicate into the mixed solution and stir the mixture evenly, so as to obtain the hydrophilic easy-to-clean coating.

In some embodiments, the step 2) is specifically to drop the wetting agent and the leveling agent into the mixed solution, stir the mixture uniformly, add water into the mixed solution, stir the mixture for 10 to 15min, and finally add potassium silicate into the mixed solution, stir the mixture for 10 to 15min to obtain the hydrophilic easy-to-clean coating.

In the preparation method of the invention, the adding sequence of the raw materials is very important, and the change of the sequence influences the performance of the coating. The inventor finds that the paint obtained by mixing the silicic acid dispersoid and the silane coupling agent with other materials is transparent and has good cleaning performance only after being uniformly mixed; the adding sequence is changed, for example, the potassium silicate is mixed with the silicic acid dispersoid, and other materials such as the silane coupling agent and the like are added, so that the obtained coating is turbid and easy to clean, and the effect is not ideal.

The invention also relates to application of the hydrophilic easy-cleaning coating in the fields of metal and glass.

In another aspect, the invention also relates to the application of the hydrophilic easy-cleaning coating in kitchen electric products.

In some embodiments, the kitchen appliance is a refrigerator.

In another aspect of the invention, a refrigerator is provided, wherein the surface of the outer shell and/or the inner decorative glass of the refrigerator is provided with a coating, and the coating is formed by the hydrophilic easy-to-clean coating.

The invention has the beneficial effects that:

the hydrophilic easy-cleaning coating can be used as a coating applied to materials such as metal, glass and the like, and has the advantages of easy cleaning, good adhesion, high hardness, good flexibility, high impact resistance, acid and alkali resistance, high and low temperature resistance, salt mist resistance, high temperature and humidity resistance, durability and the like; and the components are simple, the quality control is easy, and the cost is low.

The preparation method of the hydrophilic easy-cleaning coating has simple operation, but has higher requirements on the adding sequence of the raw materials. The preparation efficiency of the coating is further improved by limiting the specific adding sequence.

Drawings

FIG. 1 is a graph of the greasy dirt cleaning performance of a stainless steel substrate and a coated stainless steel substrate;

FIG. 2 is a graph of cleaning performance tests of a stainless steel substrate, a hydrophilic coating, and a hydrophobic coating;

FIG. 3 is a graph of cleaning performance testing of glass substrates and coated glass substrates.

Detailed Description

Specifically, the technical scheme adopted by the invention is as follows:

The coating formula of the invention belongs to a water glass system, and the structural formula of the coating is M₂O·nSiO₂·mH₂O, where M is K, Na, Li or other alkali metal, and n is the modulus, i.e. SiO₂/M₂The molar ratio of O, and m is the molecular number of crystal water; generally, as the modulus increases, the binding ability, binding strength and water resistance of the silicate may be improved, but the stability and film forming property of the coating may be deteriorated; the inventor researches and discovers that the ratio of potassium to sodium to lithium has great influence on the water resistance, acid and alkali resistance and other properties of the coating. By adjusting the modulus and the proportion of each substance in silicate in a water glass system, the product with good comprehensive performance can be preparedThe paint is easy to clean.

In some embodiments, the hydrophilic easy-cleaning coating further comprises 0.1-0.2 part by weight of wetting agent

In some embodiments, the kitchen appliance is a refrigerator.

The technical solutions of the present invention are further described below with reference to the drawings and specific examples, but the present invention is not limited to these specific embodiments. The test methods used in the examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are commercially available reagents and materials unless otherwise specified.

Wherein the commercial product is a water glass system hydrophilic coating, the main component of which is potassium silicate and contains a small amount of sodium silicate and Al₂O₃And the like.

Example 1

Consists of the following components:

21.27 parts of potassium silicate, 58.09 parts of silicic acid dispersoid, 0.46 part of silane coupling agent, 19.9 parts of water, 0.14 part of wetting agent and 0.14 part of leveling agent.

Wherein the modulus of the potassium silicate is 3.8; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the mixture is 2.7; the silane coupling agent is mercaptopropyl trimethoxysilane; the wetting agent is polyether modified organic silicon; the leveling agent is an organic silicon leveling agent.

Preparation:

1) adding a silane coupling agent into the silicic acid dispersoid under the stirring state of 150rpm, continuously stirring until the solution is clear, and stirring for 10min to obtain a mixed solution.

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 10min, finally adding potassium silicate, and stirring for 15min to obtain the hydrophilic easy-to-clean coating 1.

Example 2

Consists of the following components:

18 parts of potassium silicate, 61 parts of silicic acid dispersoid, 0.56 part of silane coupling agent, 20.1 parts of water, 0.17 part of wetting agent and 0.17 part of flatting agent.

Preparation:

1) adding a silane coupling agent into the silicic acid dispersoid under the stirring state of 100rpm, continuously stirring until the solution is clear, and stirring for 15min to obtain a mixed solution.

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 10min, finally adding potassium silicate, and stirring for 15min to obtain the hydrophilic easy-to-clean coating 2.

Example 3

Consists of the following components:

24 parts of potassium silicate, 55 parts of silicic acid dispersoid, 0.36 part of silane coupling agent, 20.24 parts of water, 0.2 part of wetting agent and 0.2 part of leveling agent.

Preparation:

1) adding a silane coupling agent into the silicic acid dispersoid under the stirring state of 120rpm, continuously stirring until the solution is clear, and stirring for 12min to obtain a mixed solution.

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 15min, and finally adding potassium silicate, and stirring for 10min to obtain the hydrophilic easy-to-clean coating 3.

Example 4

Consists of the following components:

18 parts of potassium silicate, 58.3 parts of silicic acid dispersoid, 0.5 part of silane coupling agent, 23 parts of water, 0.1 part of wetting agent and 0.1 part of flatting agent.

Wherein the modulus of the potassium silicate is 3.6; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the silicic acid dispersoid is 3; the silane coupling agent is aminopropyl triethoxysilane; the wetting agent is an acrylate copolymer aqueous solution; the leveling agent is a modified acrylic acid leveling agent.

Preparation:

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 15min, and finally adding potassium silicate, and stirring for 10min to obtain the hydrophilic easy-to-clean coating 4.

Example 5

Consists of the following components:

21.15 parts of potassium silicate, 61 parts of silicic acid dispersoid, 0.55 part of silane coupling agent, 17 parts of water, 0.15 part of wetting agent and 0.15 part of flatting agent.

Wherein the potassium silicate has a modulus of 4; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the silicic acid dispersoid is 2.4; the silane coupling agent is pentafluorophenyl dimethylchlorosilane; the wetting agent is an acrylate copolymer aqueous solution; the leveling agent is silicone hexaacrylate copolymer.

Preparation:

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 15min, and finally adding potassium silicate, and stirring for 10min to obtain the hydrophilic easy-to-clean coating 5.

Example 6

Consists of the following components:

22 parts of potassium silicate, 56 parts of silicic acid dispersoid, 0.4 part of silane coupling agent, 21.3 parts of water, 0.15 part of wetting agent and 0.15 part of flatting agent.

Wherein the modulus of the potassium silicate is 3.9; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the silicic acid dispersoid is 2.5; the silane coupling agent is 3- (2, 3-epoxypropoxy) propyl trimethoxy silane; the wetting agent is an acrylate copolymer aqueous solution; the leveling agent is silicone hexaacrylate copolymer.

Preparation:

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 12min, and finally adding potassium silicate, stirring for 12min to obtain the hydrophilic easy-to-clean coating 6.

Example 7

Consists of the following components:

21.2 parts of potassium silicate, 55 parts of silicic acid dispersoid, 0.4 part of silane coupling agent, 23 parts of water, 0.2 part of wetting agent and 0.2 part of flatting agent.

Wherein the modulus of the potassium silicate is 3.6; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the mixture is 2.7; the silane coupling agent is ethoxy dimethyl [3- (oxiranyloxy) propyl ] silane; the wetting agent is polyether modified organic silicon; the leveling agent is a modified acrylic acid leveling agent.

Preparation:

1) adding a silane coupling agent into the silicic acid dispersoid under the stirring state of 1000rpm, continuously stirring until the solution is clear, and stirring for 15min to obtain a mixed solution.

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 10min, finally adding potassium silicate, and stirring for 15min to obtain the hydrophilic easy-to-clean coating 7.

Example 8

Consists of the following components:

Wherein the modulus of the potassium silicate is 3.8; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the mixture is 2.7; the silane coupling agent is trimethoxy [3- (oxiranylmethoxy) propyl ] silane; the wetting agent is polyether modified organic silicon; the leveling agent is silicone hexaacrylate copolymer.

Preparation:

1) adding a silane coupling agent into the silicic acid dispersoid under the stirring state of 100rpm, continuously stirring until the solution is clear, and stirring for 14min to obtain a mixed solution.

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 14min, and finally adding potassium silicate, and stirring for 14min to obtain the hydrophilic easy-to-clean coating 8.

Comparative example 1

The potassium silicate with the modulus of 5 is selected, and the other components, the proportion and the preparation method are the same as those of the example 1, so that the coating 9 is obtained.

Comparative example 2

The silicic acid dispersion with the modulus of 2 was selected, and the other composition ratios and preparation methods were the same as in example 1, to obtain a coating 10.

Comparative example 3

The amount of potassium silicate was adjusted to 30 parts, and the other composition ratios and preparation methods were the same as in example 1, to obtain coating 11.

Comparative example 4

The composition and the ratio are the same as those of example 1.

Preparation:

1) potassium silicate was added to the silicic acid dispersion under stirring at 150rpm, and further stirred for 10min to obtain a mixed solution.

2) And (3) dropwise adding a wetting agent and a flatting agent into the mixed solution, uniformly stirring, then adding water, stirring for 10min, finally adding a silane coupling agent, and stirring for 15min to obtain the coating 12.

The order of addition of the raw materials was changed during the preparation process, and it was found that the resulting coating 12 was cloudy, poor in transparency, and poor in cleaning performance.

Coating the coatings prepared in the examples and the comparative examples on a metal or glass substrate, and curing by using ultraviolet light to obtain the substrate with the coating, wherein the coatings formed by the coatings 1-11 are correspondingly numbered as coatings 1-11. Then, each performance test is respectively carried out.

First, adhesion, hardness and flexibility tests

1. Adhesion test

The test method comprises the following steps: 100 small squares with the interval of 1mm are criss-cross scribed on the coating by a blade or a scriber, the metal substrate is deeply scribed, burrs on the scratches are removed, an adhesive tape (the number is 3M 610 or permanently large) covers the scratch area along the 45-degree direction of the hundred grids, the adhesive tape is flattened, no air bubbles exist between the adhesive tape and the coating, the two ends of the adhesive tape are pulled, the adhesive tape is quickly torn off in the 90-degree direction of the surface of the test plate, no coating falls off, and the process is repeated for three times.

2. Hardness test

The test method comprises the following steps: the test was carried out using a zhonghua drawing/mitsubishi pencil (a higher hardness (7-9H) test using mitsubishi pencil, since the highest hardness of the zhonghua drawing pencil used was 6H, and the test results showed that the coating hardness was higher than 6H), according to the specifications of GB/T6739.

3. Flexibility test

The test method comprises the following steps: reference GB/T6742, samples are in

The cylindrical paint film bender was bent and examined for any damage to the coating surface.

4. And (3) impact resistance test:

the test method comprises the following steps: and (3) placing the coating of the coating test piece upwards on an anvil, wherein the distance between the impacted part of the test piece and the edge is not less than 15mm, and the distance between the edges of each impact point is not less than 15 mm. The weight (with a mass of 1000 + -1 g) is fixed at the height of 500mm of the slide cylinder by the control device, and the weight can freely fall on the punch by pressing the control button. The weight is lifted up, the test plate is taken out, and 3 times of impact tests are carried out on the same test plate at the same impact height. If the coating at the impact point on the test piece is not damaged, cracked or fallen, the test piece is qualified.

The performance test results are shown in table 1; the coating prepared by the embodiment of the invention has high transparency, very good adhesive force, high hardness, good flexibility and good impact resistance, and is not easy to scratch or damage when in use; the basic performance of the commercial product is equivalent to that of the invention; from the results of the performance tests of the coatings 9 to 11, it can be seen that when a high modulus potassium silicate is used (comparative example 1), the resulting coating fails in flexibility and impact resistance because too high modulus deteriorates the stability and moldability of the coating; when a low modulus silicic acid dispersion was used (comparative example 2), the coating hardness obtained was low; when the amount of potassium silicate used was too large (comparative example 3), the obtained coating had an unsatisfactory impact resistance. That is, the processability and mechanical properties of the coatings 9 to 11 are problematic, so that even if other properties such as cleaning property and the like are tested properly, they are not suitable for practical use.

TABLE 1 Performance test results of the coatings

Sample (I)	Adhesion force	Hardness of	Flexibility	Impact resistance
					Coating 1	Level 0	9H	No damage to the surface	Qualified
Coating 2	Level 0	9H	No damage to the surface	Qualified
					Coating 3	Level 0	9H	No damage to the surface	Qualified
Coating 4	Level 0	9H	No damage to the surface	Qualified
					Coating 5	Level 0	8H	No damage to the surface	Qualified
Coating 6	Level 0	8H	No damage to the surface	Qualified
					Coating 7	Level 0	8H	No damage to the surface	Qualified
Coating 8	Level 0	9H	No damage to the surface	Qualified
					Is commercially available	Level 0	9H	No damage to the surface	Qualified
Coating 9	Level 1	9H	Surface damage	Fail to be qualified
					Coating 10	Level 0	6H	No damage to the surface	Qualified
Coating 11	Level 0	9H	No damage to the surface	Fail to be qualified

Second, Water contact Angle test

The contact angle is the angle θ at which a tangent to the gas-liquid interface at the intersection of the gas, liquid and solid passes through the boundary between the liquid and the solid-liquid, and is a measure of the degree of wetting. If theta is less than 90 degrees, the surface of the solid is hydrophilic, namely, the liquid is easier to wet the solid, the smaller the contact angle of the solid is, the more spread the water on the surface of the substrate is, and the better the easy cleaning performance is; if θ >90 °, the solid surface is hydrophobic, i.e. the liquid does not easily wet the solid and easily moves over the surface.

Table 2 mainly examines the water contact angle before and after coating on the stainless steel substrate; and the change in water contact angle before and after being subjected to harsh conditions. Wherein, after the treatment under the harsh condition, the surface of the coating needs to be cleaned by water until no reagent remains.

The results are shown in table 2, and it can be seen that the initial water contact angle of the coating of the present invention is similar to that of the commercially available coating, but after the coating is soaked in water at normal temperature and tested for alkali resistance, the water contact angle of the coating of the present invention becomes small, the hydrophilic property increases, while the water contact angle of the commercially available product becomes large, and the cleaning performance becomes poor; after an acid resistance test, the water contact angles of the coating disclosed by the invention and a commercially available coating are increased, but the water contact angle of the coating disclosed by the invention is greatly increased less than that of a commercially available product; after the test of the humidity resistance, the heat resistance, the high temperature and the strong alkali, the water contact angles of the two become small, and the variation degree is not very different. The coatings of the comparative examples (coatings 9-11) have water contact angle performances similar to those of the coating claimed by the invention, and generally, the coating disclosed by the invention still has very good cleaning performance in a complex environment and is better than that of a commercially available product. Particularly suitable for use in kitchen environments and the like, for example: the coating is applied to the surface treatment coating of kitchen electrical products, and the easy cleaning performance of the coating is realized.

Table 2 water contact angles of different coatings under different conditions

Third, cleaning performance test

1. Cleaning performance test 1:

coating the oil stain on the surfaces of the stainless steel base material and the stainless steel base material with the coating, curing for 10 days at room temperature, wiping with clean water by using a rag, and then wiping with a dry rag.

As shown in fig. 1, fig. 1A and fig. 1B are graphs of oil cleaning performance of the surfaces of the 430 stainless steel substrate and the substrate coated with the coating 1, respectively, and it can be seen that oil is remained on the surface of the 430 stainless steel and cannot be removed, while the surface of the coating of the present invention is clean and non-greasy, and has excellent new cleaning performance.

2. Cleaning performance test 2:

the surface of the stainless steel substrate, the surface coated with the coating 1, and the surface of the hydrophobic coating (commercially available) are marked with an oil pen, and then wetted with clear water and wiped, and the results are shown in fig. 2, in which fig. 2A, 2B, and 2C are the surface of the stainless steel substrate, the surface coated with the coating 1, and the surface of the hydrophobic coating, respectively; i is the mark of an oil pen, ii is the mark of an oil pen soaked with water, and iii is after wiping. It can be seen that the oil pen marks both on the stainless steel substrate and the coating of the invention, while there is only a very light mark on the hydrophobic coating. After the stainless steel substrate and the hydrophobic coating are soaked in water, the oil pen marks on the stainless steel substrate and the hydrophobic coating are not changed, and the oil pen marks on the coating have the phenomenon of ink floating. After wiping, the oily pen marks on the surfaces of the stainless steel substrate and the hydrophobic material still exist, and the marks hardly change with naked eyes; the oily pen mark on the coating is completely wiped clean. In conclusion, it can be seen that the hydrophilic coating of the present invention has very good anti-oil, easy-to-clean properties.

3. Cleaning performance test 3:

the surfaces of the glass and the glass coated with the coating 1 are marked by an oil pen and are soaked by water, and the result is shown in fig. 3, wherein fig. 3A shows that the surface of the glass marked by the oil pen is changed before (left picture 3A) and after (right picture 3A) the surface of the glass marked by the oil pen is soaked by water, and the oil pen mark is hard to be formed and basically has no change; FIG. 3B shows the change of the surface of the coating 1 marked by the oil-based pen before (left image 3B) and after (right image 3B) being soaked by water, and it can be seen that the ink floats after being soaked by water; indicating that the coating of the present invention has very excellent cleaning performance.

Fourthly, testing the acid resistance, alkali resistance and salt spray resistance

1. Acid resistance test

The test method comprises the following steps: preparing an acidic solution with pH of 3.0 by using analytically pure solid acetic acid (mixing white vinegar with total acid amount of 3.0-3.5 g/100 mL and distilled water in a ratio of 1: 5), and soaking in the acidic solution for 48 h. The experimental temperature is 23 +/-2 ℃, and the sunshine is avoided in the experimental process. With the coated surface facing upward, and sealed with a cling film and taped at the container opening to reduce evaporation of water. And (3) washing the white vinegar on the surface of the test plate with clear water, standing the test piece for not less than 15 h.

2. Alkali resistance test

The test method comprises the following steps: and (3) soaking the test plate in Mr. wiferon solvent at the temperature of 23 +/-2 ℃ for 48 hours. With the coated surface facing upward, and sealed with a cling film and taped at the container opening to reduce evaporation of water. And (3) washing Mr. wiferon on the surface of the test plate with clear water, and standing the test piece for no less than 15 h.

3. Salt spray resistance test

The test method comprises the following steps: the sample is placed for 72 hours under the conditions that the test temperature is 35 +/-2 ℃, the saturation temperature is 42 +/-1 ℃, the pH value is 6-7 and the salt water concentration is 5%, and rust on the surface of the coating is checked (the rust is not checked in an area 5mm away from the edge).

4. Long term salt spray resistance test

The test method comprises the following steps: sealing wax on the periphery of the base material, placing for 168 hours under the conditions that the test temperature is 55 +/-2 ℃, the saturation temperature is 42 +/-1 ℃, the pH value is 6-7 and the salt water concentration is 5%, and checking rust on the surface of the coating (the rust is not checked in an area 5mm away from the edge).

5. Oil pen test

The test method comprises the following steps: oil stains on the surface of the range hood are simulated by taking Japanese zebra (zebra) MO-150-MC oily mark notes, and no notes remain on the surface of the coating after wiping. The grade of the wiping force to the water easy-cleaning performance is judged as follows: the wiping force is less than or equal to 1.0kg, and the wiping force is excellent; the wiping force is more than 1 and less than or equal to 1.5kg, and is good; the wiping force is more than 1.5 and less than or equal to 2.0kg, and the result is satisfied.

The test results are shown in table 3, and it can be seen that after passing through the complex environment of acid and alkali resistance, the coating of the invention has no undesirable phenomena of blushing and powdering, wrinkle, bubble, spot, peeling and the like, and the oily pen tests pass; the coating of the commercial product is whitish, and the oil pen test fails; the high modulus potassium silicate coating (coating 9) and the high proportion potassium silicate coating (coating 11) have no undesirable phenomena of blushing and powdering, wrinkling, bubbling, spots, peeling and the like, and the oily pen tests and passes; the low modulus silicic acid dispersion coating (coating 10) was free from blushing, chalking, blistering, spotting, flaking, and other undesirable phenomena, but failed the oil pen test. After a salt spray resistance test, the coating has no bad phenomena of whitening, bubbling, cracking and the like, the base material has no rust, the hydrophilicity is basically unchanged, and an oily pen test is passed; the coating of the commercial product is whitish in appearance and reduced in hydrophilicity, and an oil pen test is passed; the high-modulus potassium silicate coating (coating 9) is whitish in appearance, reduced in hydrophilicity and failed in an oil pen test; the low modulus silicic acid dispersion coating (coating 10) and the high proportion potassium silicate coating (coating 11) have no undesirable phenomena of blushing, blistering, cracking and the like in appearance, no rust on the substrate, basically unchanged hydrophilicity, and passing of an oil pen test. After long-term salt spray resistance test, the surface of the coating is free from corrosion, the appearance is free from whitening, bubbling, cracking and other unfavorable phenomena, the base material is free from rust, and an oily pen test passes; the surface of the coating of the commercial product is whitish, the substrate is slightly rusty, and the oily pen test fails; the surface of the high-modulus potassium silicate coating (coating 9) is whitish, the substrate is rusty, and the oil pen test fails; the low modulus silicic acid dispersion coating (coating 10) and the high proportion potassium silicate coating (coating 11) have no corrosion on the surface, no blushing, blistering, cracking and other adverse phenomena on the appearance, no rust on the substrate, and good results on an oil pen test. In general, the coating disclosed by the invention can better resist acid-base salt fog and other complex environments and still has good easy-cleaning performance in the complex environments.

Table 3 coating performance test results

Fifth, high and low temperature resistance test

1. High temperature resistance test 1:

the test method comprises the following steps: the test plate was placed at 200. + -. 5 ℃ for 1 hour, and the surface properties of the coating were examined at room temperature.

2. High temperature resistance test 2:

the test method comprises the following steps: the test plate was placed in an environment of 400. + -. 5 ℃ for 1 hour, and the surface properties of the coating were examined in an environment of room temperature.

3. And (3) low temperature resistance test:

the test method comprises the following steps: the test plate was placed at-25. + -. 3 ℃ for 1 hour and the surface properties of the coating were examined at room temperature.

4. And (3) high and low temperature impact resistance test:

the test method comprises the following steps: placing the sample in an environment of 200 + -5 deg.C for 20min, placing the sample in an environment of-25 + -3 deg.C for 20min as a cycle, continuing for 3 cycles, and inspecting the surface condition of the sample after the test.

5. Testing with an oil pen:

The test results are shown in table 4, and it can be seen that after the high temperature resistance test, the coating of the invention has no cracking and dropping appearance, no obvious yellowing (color difference delta E is less than or equal to 3.0), and good oily pen test; although the coating of the commercially available product has no cracking or shedding in appearance and no obvious yellowing (the color difference delta E is less than or equal to 3.0), the test result of the oil pen is passed; the high-modulus potassium silicate coating (coating 9) is cracked and dropped in appearance, has no obvious yellowing (the color difference delta E is less than or equal to 3.0), and fails in an oil pen test; the low-modulus silicic acid dispersion coating (coating 10) and the high-proportion potassium silicate coating (coating 11) have the advantages of no cracking, no falling, no obvious yellowing (the color difference delta E is less than or equal to 3.0) and passing of an oil pen test. After high and low temperature impact resistance tests, the coating disclosed by the invention has no cracking and falling appearance, no obvious yellowing (the color difference delta E is less than or equal to 3.0), and good oily pen test; the appearance of the coating of the commercial product has cracking and falling phenomena, and the oil pen test fails; the high-modulus potassium silicate coating (coating 9) has cracking phenomenon in appearance, and the oily pen test fails; the low modulus silicic acid dispersion coating (coating 10) and the high proportion potassium silicate coating (coating 11) have no abnormal phenomena of cracking, falling off, discoloration and the like, and pass the oil pen test. After low temperature resistance testing, the coating has no abnormal phenomena such as cracking, falling, color change and the like, and an oil pen has good testing; the appearance of the coating of the commercial product has cracking phenomenon, and the oil pen test fails; the high-modulus potassium silicate coating (coating 9) has cracking and falling phenomena in appearance, and fails an oil pen test; the low modulus silicic acid dispersion coating (coating 10) and the high proportion potassium silicate coating (coating 11) do not crack or fall off; no obvious yellowing (the color difference delta E is less than or equal to 3.0), and the oily pen tests pass. In conclusion, the surface performance of the coating of the invention and the commercial products is basically unchanged in a high-temperature environment, but the cleaning performance of the coating of the invention is better than that of the commercial products; the modulus of the potassium silicate in the formula of the invention is changed, and the surface performance and the cleaning performance of the coating are reduced; changing the modulus of the silicic acid dispersion or the amount of potassium silicate in the formulation of the present invention has little effect on the surface properties of the coating, but reduces cleaning performance. In a complex environment with low temperature and high and low temperature impact resistance, the coating of the invention shows that the performance and the cleaning performance are obviously superior to those of a product sold in the market; the modulus of the potassium silicate in the formula of the invention is changed, and the surface performance and the cleaning performance of the coating are reduced; changing the modulus of the silicic acid dispersion or the amount of potassium silicate in the formulation of the present invention has little effect on the surface properties of the coating, but reduces cleaning performance.

Table 4 coating performance test results

Sixth, durability test

1. Easy clean durability test 1:

the test method comprises the following steps: a reciprocating friction test machine is adopted for testing, the weight is increased by 2.0kg vertically, and a polyester fiber or cotton rag is dipped in 5% of a detergent solvent to perform reciprocating wiping above the coating. The rag should be dipped with 5% detergent solution, and the detergent is common detergent (strong detergent such as Mr. Wilmanson with strong alkali and strong oxidizing property should not be used). The wipes need to be replaced every 200 times.

And (3) judging standard: wherein, the coating is divided into three grades which are respectively excellent, good and qualified; among them, excellent: the surface of the coating is not damaged after 10000 times of wear-resisting experiments, and the oil pen test is qualified; good: after 6000 times of wear-resisting experiments, the surface of the coating is not damaged, and the oil pen test is qualified; and (4) qualification: after 3000 times of wear-resistant experiments, the surface of the coating is not damaged, and the oil pen test is qualified.

2. Easy clean durability test 2

The test method comprises the following steps: steel wool, 5% detergent, 5000 times.

3. Testing with an oil pen:

The test results are shown in table 5, after the durability test of the rag, the sponge surface test of the coating of the invention is excellent, and the rough surface test of the scouring pad is good; comparable to commercially available products, low modulus silicic acid dispersion coatings (coating 10) and high proportion potassium silicate coatings (coating 11); the high modulus potassium silicate coating (coating 9) was tested for surface damage and there was a coating peel-off condition. After the durability test of the steel wool, the coating has no abnormal phenomena such as obvious scratch, falling off and the like, and the hydrophilicity is basically unchanged; the oil pen tests and passes, comparable to the commercial product, low modulus silicic acid dispersion coating (coating 10) and high ratio potassium silicate coating (coating 11); the high modulus potassium silicate coating (coating 9) was tested for surface damage and there was a coating peel-off condition. It can be seen that the coating of the present invention has good durability and good easy-to-clean performance even after long wiping.

TABLE 5 coating easy clean durability test results

It will be appreciated by those skilled in the art that the use of the present invention is not limited to the specific applications described above. The invention is also not limited to the preferred embodiments thereof with respect to the specific elements and/or features described or depicted herein. It should be understood that the invention is not limited to the disclosed embodiment or embodiments, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.

Claims

1. The hydrophilic easy-cleaning coating is characterized by comprising the following components in parts by weight:

18-24 parts of potassium silicate, 55-61 parts of silicic acid dispersoid, 0.36-0.56 part of silane coupling agent, 17-23 parts of water and 0.2-0.4 part of auxiliary agent;

wherein the modulus of the potassium silicate is 3.6-4.0; the silicic acid dispersoid is a mixture of lithium silicate and sodium silicate, and the modulus of the silicic acid dispersoid is 2.4-3.0;

the preparation method of the hydrophilic easy-cleaning coating comprises the following steps:

2. A hydrophilic easy-to-clean coating according to claim 1, wherein the auxiliary agent is at least one selected from a wetting agent and a leveling agent.

3. A hydrophilic easy-to-clean paint according to claim 1, wherein the silane coupling agent is selected from at least one of aminopropyltriethoxysilane, mercaptopropyltrimethoxysilane, pentafluorophenyl dimethylchlorosilane, 3- (2, 3-glycidoxy) propyltrimethoxysilane, ethoxydimethyl [3- (oxiranoxy) propyl ] silane, trimethoxy [3- (oxiranylmethoxy) propyl ] silane.

4. A method for preparing a hydrophilic easy-to-clean coating according to any one of claims 1 to 3, comprising the steps of:

5. A preparation method of a hydrophilic easy-to-clean coating according to claim 4, wherein the step 1) is specifically that a silane coupling agent is added into a silicic acid dispersion under stirring, and the stirring is carried out until the solution is clear, so as to obtain a mixed solution.

6. The preparation method of the hydrophilic easy-to-clean coating according to claim 4, wherein the step 2) is specifically that after the auxiliary agent is dropped into the mixed solution and is uniformly stirred, water and potassium silicate are added and are uniformly stirred, and the hydrophilic easy-to-clean coating is obtained.

7. Use of a hydrophilic easy-to-clean coating according to any one of claims 1 to 3 in kitchen electrical products.

8. The use of claim 7, wherein the kitchen appliance is a refrigerator.

9. A refrigerator characterized in that the surface of the outer case and/or the interior glass of the refrigerator is provided with a coating layer formed of the hydrophilic easy-to-clean coating material according to any one of claims 1 to 3.