CN119039815A

CN119039815A - Acid and alkali resistant environment-friendly inorganic coating and preparation method thereof

Info

Publication number: CN119039815A
Application number: CN202411189466.0A
Authority: CN
Inventors: 赵大军; 赵丽芳
Original assignee: Zhuhai Lannuo New Material Technology Co ltd
Current assignee: Zhuhai Lannuo New Material Technology Co ltd
Priority date: 2024-08-28
Filing date: 2024-08-28
Publication date: 2024-11-29
Anticipated expiration: 2044-08-28
Also published as: CN119039815B

Abstract

The invention discloses an acid and alkali resistant environment-friendly inorganic coating and a preparation method thereof, wherein the acid and alkali resistant environment-friendly inorganic coating is prepared from the following raw materials, by weight, 20-28 parts of silicate, 10-20 parts of silica sol, 30-50 parts of pigment and filler, 0.5-1 part of thickener, 0.5-1 part of alkali resistant dispersing agent, 20-45 parts of deionized water and 0.5-1 part of water-increasing agent. The silicate is at least one of sodium silicate, potassium silicate, calcium silicate and aluminum silicate. The alkaline silica sol is nano-scale silica sol, has the average particle size of not more than 20nm, the mass fraction of sodium oxide of not more than 0.25%, the viscosity of not more than 15mpa.s and the average particle size of 8-20 nm, and has the excellent performances of low metal content, high uniform distribution, good stability and the like. The pigment and filler is at least one of quartz powder with 500-1500 meshes, talcum powder, calcium carbonate, titanium white and barium sulfate. The invention overcomes the defects of the prior art, can further improve the overall stability and fluidity of the paint, and has higher social use value and application prospect.

Description

Acid and alkali resistant environment-friendly inorganic coating and preparation method thereof

Technical Field

The invention relates to the technical field of inorganic coatings, in particular to an acid and alkali resistant environment-friendly inorganic coating and a preparation method thereof.

Background

After the international environmental protection laws are promulgated, the paint industry as a main pollution source is developed towards low pollution and environmental protection, and the content of organic Volatile (VOC) of paint is limited in all countries of the world. With the continuous development of the coating industry, low-pollution environment-friendly coating products are more and more divided into two major types of organic coatings and inorganic coatings, but most of the existing organic coatings contain polymers such as acrylic ester or PVC, the coatings have slight corrosiveness to buildings and poor dust absorption and weather resistance and still bring certain environmental pollution, and the existing inorganic coatings are environment-friendly, but have the defects of poor adhesiveness, poor acid and alkali resistance and poor flame retardant effect, and cracks are easy to occur in the process of brushing and forming films.

Especially in the field of constructional engineering, the coating not only has the effect of beautifying the appearance of a building, but also plays a vital role in the aspect of protecting the building. The coating for the building outer wall is required to be exposed to the external environment for a long time and is corroded by air, ultraviolet rays, rainwater and chemical substances, so that the coating not only needs to meet the requirements on basic performances such as mechanical strength and the like, but also needs to have excellent acid and alkali corrosion resistance, and meanwhile, in order to prolong the protection effect and the service life, good adhesiveness and cracking resistance are also essential, and the conventional outer wall coating is often mildewed, even falls off after being painted for a period of time, so that the aesthetic property of the wall is seriously influenced, and in addition, the high temperature resistance of the coating is also required to be improved, so that the long-term use of the coating is ensured.

Currently, there are also some applications and studies of aqueous inorganic coatings in the prior art. For example, chinese patent CN109777162A discloses a water-based interior wall coating using inorganic material as film forming material and its preparation method, in which the diatomite is diatomite loaded with nano titanium dioxide, and contains various functional auxiliary agents, and its components are complex and various, and from the embodiment mode, every component is a key condition, and its lack or substitution can bring adverse effect to coating property, and the properties of water resistance, friction resistance and hardness are not more objectively and comprehensively described.

In the environment-friendly water-based PVA modified interior wall functional coating, modified PVA emulsion is taken as a main raw material, and is matched with hydrophobicity, so that the wax emulsion capable of preventing water vapor from penetrating is used, and the effects of water resistance and brushing resistance are achieved.

In the existing water-based inorganic paint, the adopted technical means are different in order to solve the technical problems of water resistance, surface hardness, wear resistance and the like of the water-based inorganic paint. How to further improve the performances of water resistance, binding force with the front surface, brushing resistance and the like of the water-based inorganic coating is an important technical problem to be solved by the invention.

Disclosure of Invention

In order to solve the problems mentioned in the background art, the invention provides an acid and alkali resistant environment-friendly inorganic coating and a preparation method thereof.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

The environment-friendly inorganic paint is prepared from the following raw materials, by weight, 20-28 parts of silicate, 10-20 parts of silica sol, 30-50 parts of pigment and filler, 0.5-1 part of thickener, 0.5-1 part of alkali-resistant dispersing agent, 20-45 parts of deionized water and 0.5-1 part of water-increasing agent.

Preferably, the silicate is at least one of sodium silicate, potassium silicate, calcium silicate and aluminum silicate.

The silica sol is preferably alkaline silica sol, the silica content is 25-35%, the pH is 8.0-9.5, the alkaline silica sol is nanoscale silica sol, the average particle size is not more than 20nm, the mass fraction of sodium oxide is less than or equal to 0.25%, the viscosity is less than or equal to 15mpa.s, the average particle size is 8-20 nm, and the silica sol has the excellent performances of low metal content, high uniform distribution, good stability and the like.

Preferably, the pigment and filler is at least one of quartz powder, talcum powder, calcium carbonate, titanium pigment and barium sulfate with the mesh number of 500-1500.

Preferably, the thickener is an aqueous polyamide wax comprising the steps of:

s1, adding a heat stabilizing additive, aqueous polyamide wax slurry and an organic solvent into a reaction kettle, and heating to 125-130 ℃ until the heat stabilizing additive and the aqueous polyamide wax slurry are completely dissolved in the corresponding organic solvent, wherein the content of effective active substances in the aqueous polyamide wax slurry is 20%, and the acid value is 12.0-13.0mgKOH/g;

S2, slowly adding at least one organic amine, starting to cool after the addition, adding a surfactant when the temperature is reduced to 75-85 ℃, and stirring and dispersing at the constant temperature to obtain a first reaction material;

s3, heating deionized water to 85-90 ℃, slowly adding the first reaction materials dispersed in the S2 into the heated deionized water, controlling the stirring speed to be 800-1200rmp, and stopping stirring when the temperature of the mixed solution is reduced to below 60 ℃;

and S4, finally cooling to room temperature to obtain the aqueous polyamide wax thickener.

In the preparation process of the thickener, the material which also contains an amide group component is selected, so that the interaction with the aqueous polyamide wax slurry is more favorable, the compatibility is improved, and the crystallization capability of the aqueous polyamide wax is improved if the acid value of the polyamide wax is low, the molecular chain structure is regular, and the intermolecular hydrogen bond with an amide bond is strong, so that the aqueous polyamide wax is very suitable for being used as a crystal nucleus to induce the molecular chain to be orderly arranged.

Because the thermostable auxiliary component is introduced in the pulping process, compared with the existing aqueous polyamide wax pulp on the market, the aqueous polyamide wax pulp prepared by the process has the characteristics that the aqueous inorganic coating has excellent heat storage performance, and the anti-sinking and anti-sagging performances are hardly affected after heat storage. The anti-sinking and anti-sagging performances of the common aqueous polyamide wax are greatly reduced after heat storage, and the storage of the aqueous coating in a high-temperature environment brings great risks.

Preferably, the heat-stable auxiliary agent is polyamide resin obtained by reacting monoacid and diamine, wherein the monoacid is at least one of n-octanoic acid, n-nonanoic acid, n-decanoic acid, lauric acid and 12-hydroxystearic acid, and the diamine is at least one of 4,4' -diamino dicyclohexylmethane, 3' -dimethyl-4, 4' -diamino dicyclohexylmethane and polyamine.

Preferably, the organic solvent is at least one of propylene glycol n-propyl ether and propylene glycol monobutyl ether;

the organic amine is at least one of amine octane, dodecylamine, octadecylamine and N-diethyl ethanolamine.

Preferably, the surfactant is at least one of fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether sodium sulfate, polyoxyethyl nonylphenyl ether and alkyl aryl polyoxyethylene ether.

Preferably, the alkali-resistant dispersing agent is at least one of sodium lignin sulfonate and maleic acid-acrylic acid copolymer;

the water-increasing agent is sodium methyl siliconate.

The preparation method of the acid and alkali resistant environment-friendly inorganic coating further comprises the following steps:

S1, grinding pigment and filler and silicate to fineness less than 10 mu m according to the raw materials in parts by weight, and then mixing to obtain a mixed material;

S2, adding the mixed material obtained in the step S1 into silica sol, and adding deionized water to stir to obtain slurry;

And S3, adding the thickener, the alkali-resistant dispersing agent and the water-adding agent into the slurry obtained in the step S2, and uniformly stirring to obtain the acid-alkali-resistant environment-friendly inorganic coating.

Compared with the prior art, the invention has the beneficial effects that:

1. The nano alkaline silica sol with the average particle size not greater than 20nm is added, so that the nano alkaline silica sol has higher surface activity, is beneficial to improving the compactness of a gelled structure, and further improves the coating strength of the inorganic coating after curing, the pH value of the nano alkaline silica sol is 8.0-9.5, the stable state of the sol is beneficial to ensuring, particle aggregation and sedimentation are reduced, and the particle size of the alkaline silica sol is kept, so that the coating strength is improved.

2. According to the invention, the water-based polyamide wax thickener is added in the preparation process of the coating, when the temperature is increased, the selected polyamide wax has a low acid value, a regular molecular chain structure and intermolecular hydrogen bonds with amide bonds, the crystallization capability is high, the crystal structure of the material is not easily damaged, and the hydrogen bonds are not easily damaged in the system, so that serious layering and bottoming phenomena of the water-based coating are avoided, the overall stability and flowability of the coating can be further improved, and the water-based coating has high social use value and application prospect.

Detailed Description

The technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Unless otherwise specified, the raw materials used in the present invention are all derived from conventional products purchased in the market. The aqueous polyamide wax slurry is purchased from Zhejiang Feng Hong New Material Co., ltd, and the model is PA-600;

The alkaline silica sol is obtained from Shandong Kohn silicon source New Material Co., ltd. And has a product model of KHZCM-30 (Fe <20ppm, al <20 ppm).

Preparation example 1

The thickener is aqueous polyamide wax, comprising the following steps:

S1, adding 100g of a heat stabilization auxiliary agent, 400g of aqueous polyamide wax slurry and 250g of propylene glycol monobutyl ether into a reaction kettle, and heating to 125 ℃ until the heat stabilization auxiliary agent and the aqueous polyamide wax slurry are completely dissolved in the corresponding propylene glycol monobutyl ether;

S2, slowly adding 30g of amine octane and 25g of dodecylamine, starting to cool after the addition, adding 80g of fatty alcohol polyoxyethylene ether when the temperature is reduced to 75 ℃, and stirring and dispersing at constant temperature to obtain a first reaction material;

S3, heating deionized water to 85 ℃, slowly adding the first reaction material dispersed in the step S2 into 1000ml of heated deionized water, controlling the stirring speed to be 800rmp, and stopping stirring when the temperature of the mixed solution is reduced to below 60 ℃;

The heat stabilizing assistant is polyamide resin obtained through the reaction of n-octanoic acid and 4,4' -diamino dicyclohexyl methane.

Preparation example 2

The thickener is aqueous polyamide wax, comprising the following steps:

S1, adding 100g of a heat stabilizing additive, 400g of aqueous polyamide wax slurry and 250g of propylene glycol n-propyl ether into a reaction kettle, and heating to 125 ℃ until the heat stabilizing additive and the aqueous polyamide wax slurry are completely dissolved in the corresponding propylene glycol n-propyl ether;

S2, slowly adding 30g of octadecylamine and 25g of dodecylamine, starting to cool after the addition, adding 80g of fatty alcohol polyoxyethylene ether sodium sulfate when the temperature is reduced to 75 ℃, and stirring and dispersing at a constant temperature to obtain a first reaction material;

The heat stabilizing assistant is polyamide resin obtained through the reaction of n-capric acid and 4,4' -diamino dicyclohexyl methane.

Preparation example 3

The thickener is aqueous polyamide wax, comprising the following steps:

S2, slowly adding 30g of amine octane and 25g N-diethyl ethanolamine, starting to cool after the addition, adding 80g of polyoxyethylnonylphenyl ether when the temperature is reduced to 75 ℃, and stirring and dispersing at a constant temperature to obtain a first reaction material;

The heat stabilizing assistant is polyamide resin obtained by reacting 12-hydroxy stearic acid and 4,4' -diamino dicyclohexyl methane.

Preparation example 4

The thickener is aqueous polyamide wax, comprising the following steps:

The heat stabilizing assistant is polyamide resin obtained by reacting 12-hydroxy stearic acid and 3,3 '-dimethyl-4, 4' -diamino dicyclohexyl methane.

Preparation example 5

The thickener is aqueous polyamide wax, comprising the following steps:

s2, slowly adding 10g of amine octane, 15g of dodecylamine and 18g of octadecylamine, starting to cool after the addition, adding 80g of polyoxyethylnonylphenyl ether when the temperature is lowered to 75 ℃, and stirring and dispersing at constant temperature to obtain a first reaction material;

The heat stabilizing assistant is polyamide resin obtained by reacting 12-hydroxy stearic acid and diamine.

Preparation example 6

The thickener is aqueous polyamide wax, comprising the following steps:

S2, slowly adding 20g of dodecylamine and 15g of N-diethyl ethanolamine, starting to cool after the addition, adding 80g of alkyl aryl polyoxyethylene ether when the temperature is reduced to 75 ℃, and stirring and dispersing at a constant temperature to obtain a first reaction material;

The heat stabilizing assistant is polyamide resin obtained through the reaction of n-capric acid and 3,3 '-dimethyl-4, 4' -diamino dicyclohexyl methane.

Example 1

S1, grinding 30g of 500-mesh quartz powder and 25g of sodium silicate to a fineness of less than 10 mu m, and then mixing to obtain a mixed material;

S2, adding the mixed material obtained in the step S1 into 15g of nano alkaline silica sol with the average particle size of 15nm, the mass fraction of sodium oxide of less than or equal to 0.25%, the viscosity of less than or equal to 15mpa.s and the pH of 8.0, and adding 30ml of deionized water to stir to obtain slurry;

s3, adding 1g of the thickener prepared in the preparation example 1, 0.5g of sodium lignin sulfonate and 1g of sodium methyl siliconate into the slurry obtained in the step S2, and uniformly stirring to obtain the acid and alkali resistant environment-friendly inorganic coating.

Example 2

s1, grinding 30g of 500-mesh calcium carbonate and 25g of sodium silicate to a fineness of less than 10 mu m, and then mixing to obtain a mixed material;

S2, adding the mixed material obtained in the step S1 into 15g of nano alkaline silica sol with the average particle size of 18nm, the mass fraction of sodium oxide of less than or equal to 0.25%, the viscosity of less than or equal to 15mpa.s and the pH of 8.0, and adding 30ml of deionized water to stir to obtain slurry;

S3, adding 1g of the thickener prepared in the preparation example 2, 0.5g of sodium lignin sulfonate and 1g of sodium methyl siliconate into the slurry obtained in the step S2, and uniformly stirring to obtain the acid and alkali resistant environment-friendly inorganic coating.

Example 3

s1, grinding 30g of 500-mesh titanium dioxide and 25g of potassium silicate to a fineness less than 10 mu m, and then mixing to obtain a mixed material;

s3, adding 1g of the thickener prepared in the preparation example 3, 0.5g of sodium lignin sulfonate and 1g of sodium methyl siliconate into the slurry obtained in the step S2, and uniformly stirring to obtain the acid and alkali resistant environment-friendly inorganic coating.

Example 4

S2, adding the mixed material obtained in the step S1 into 15g of nano alkaline silica sol with the average particle size of 10nm, the mass fraction of sodium oxide of less than or equal to 0.25%, the viscosity of less than or equal to 15mpa.s and the pH of 8.0, and adding 30ml of deionized water to stir to obtain slurry;

s3, adding 1g of the thickener prepared in the preparation example 4, 0.5g of the maleic acid-acrylic acid copolymer and 1g of the sodium methyl siliconate into the slurry obtained in the step S2, and uniformly stirring to obtain the acid and alkali resistant environment-friendly inorganic coating.

Example 5

s1, grinding 30g of 500-mesh barium sulfate and 25g of potassium silicate to a fineness less than 10 mu m, and then mixing to obtain a mixed material;

s2, adding the mixed material obtained in the step S1 into 15g of nano alkaline silica sol with the average particle size of 12nm, the mass fraction of sodium oxide of less than or equal to 0.25%, the viscosity of less than or equal to 15mpa.s and the pH of 8.5, and adding 30ml of deionized water to stir to obtain slurry;

S3, adding 1g of the thickener prepared in the preparation example 5, 0.5g of the maleic acid-acrylic acid copolymer and 1g of the sodium methyl siliconate into the slurry obtained in the step S2, and uniformly stirring to obtain the acid and alkali resistant environment-friendly inorganic coating.

Example 6

s1, grinding 30g of 800-mesh titanium dioxide and 25g of sodium silicate to a fineness of less than 10 mu m, and then mixing to obtain a mixed material;

s2, adding the mixed material obtained in the step S1 into 15g of nano alkaline silica sol with the average particle size of 15nm, the mass fraction of sodium oxide of less than or equal to 0.25%, the viscosity of less than or equal to 15mpa.s and the pH of 9.0, and adding 30ml of deionized water to stir to obtain slurry;

s3, adding 1g of the thickener prepared in the preparation example 6, 0.5g of the maleic acid-acrylic acid copolymer and 1g of the sodium methyl siliconate into the slurry obtained in the step S2, and uniformly stirring to obtain the acid and alkali resistant environment-friendly inorganic coating.

Comparative example 1

S3, replacing 1g of the thickener prepared in the preparation example 1 with 1g of aqueous polyamide wax slurry with the model of PA-600 purchased from Zhejiang Feng Hong new materials, 0.5g of sodium lignin sulfonate and 1g of sodium methyl silanol, adding the aqueous polyamide wax slurry into the slurry obtained in the step S2, and uniformly stirring the aqueous polyamide wax slurry to obtain the acid and alkali resistant environment-friendly inorganic coating.

Comparative example 2

S3, replacing 1g of the thickener prepared in the preparation example 1 with 1g of an acrylic thickener with the model of N-0049, 0.5g of sodium lignin sulfonate and 1g of sodium methyl silanol purchased from the new material Co of mercuric chloride in the bergamot, adding the mixture into the slurry obtained in the step S2, and uniformly stirring the mixture to obtain the acid and alkali resistant environment-friendly inorganic coating.

Comparative example 3

And S3, adding 0.5g of sodium lignin sulfonate and 1g of sodium methyl siliconate into the slurry obtained in the step S2, and uniformly stirring to obtain the acid and alkali resistant environment-friendly inorganic coating.

Comparative example 4

Wherein no heat stabilizing aid was added during the preparation of the aqueous polyamide wax thickener of preparation example 1.

Comparative example 5

Wherein the heat stabilizing additive added in the process of preparing the aqueous polyamide wax thickener in preparation example 1 is replaced by an organotin heat stabilizer model 181# purchased from Henan Tian Jiu chemical industry products Co.

Comparative example 6

S2, adding the mixed material obtained in the step S1 into 15g of industrial silica sol purchased from Ji Ye L chemical industry Co., ltd, CAS number: 112926-00-8, and adding 30ml of deionized water to stir to obtain slurry;

Detecting items:

The coatings prepared in examples 1 to 6 and comparative examples 1 to 6 were subjected to performance tests, and specific test items include adhesion, hardness, reflectivity, thermal shock test, thermal storage performance test and corrosion resistance test, and specific test results thereof are shown in table 1:

the adhesion test method in this test example refers to ASTM D-3359 Standard test method for classifying adhesion by tape test;

hardness test reference GB/T6739-2006 "paint film hardness measured by the paint and varnish pencil method";

the reflectivity is measured by using a measuring instrument Fluxdata, the reflectivity value at the wave band of 500-1000nm is measured, and the appearance of the coating is ensured not to be damaged before the measurement;

The thermal shock test conditions are 25 ℃ per 25% RH,5 min-65 ℃ per 90% RH,2 h-25 ℃ per 25% RH,2 h-20 ℃ per 2 h-25 ℃ per 25% RH,5min, the adhesion effect is tested after repeating the above procedure 6 times, and specific grading standards refer to ASTM D-3359, standard test method for grading adhesion by tape test;

Heat storage performance test, namely sealing the materials and placing the materials in a 50 ℃ oven for two weeks;

Acid resistance, namely, testing by referring to a method in a standard GBT 50393-2017, observing foaming time, wherein the testing parameters are that 5 weight percent of H ₂SO₄ solution is used for observing the time for which the foam, the rust, the falling and the cracking can be avoided;

Alkali resistance test was performed with reference to the method in standard GBT 50393-2017, bubbling time was observed, test parameters were 5wt% NaOH solution, and how long it was possible to observe that bubbling, rust, falling, cracking could not occur.

TABLE 1

In conclusion, the coating prepared by adopting the coating disclosed by the invention has excellent acid and alkali resistance, the coating has stronger adhesive force and hardness, meanwhile, after the thickener in the preparation example is added, the prepared coating has excellent thermal shock property, the reflectivity is low and is between 1.60 and 1.65, and the reflectivity in the comparative example is as high as 2.89, so that the water-based polyamide wax thickener is proved to be added in the preparation process of the coating, the layering and bottoming phenomena of the water-based coating can be effectively avoided, the overall stability and the fluidity of the coating can be further improved, and the coating has higher social use value and application prospect.

The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.

Claims

1. The acid and alkali resistant environment friendly inorganic paint is characterized by comprising, by weight, 20-28 parts of silicate, 10-20 parts of silica sol, 30-50 parts of pigment and filler, 0.5-1 part of thickener, 0.5-1 part of alkali resistant dispersing agent, 20-45 parts of deionized water and 0.5-1 part of water enhancer.

2. The acid and alkali resistant environment friendly inorganic coating according to claim 1, wherein said silicate is at least one of sodium silicate, potassium silicate, calcium silicate and aluminum silicate.

3. The acid and alkali resistant environment-friendly inorganic coating is characterized in that the silica sol is alkaline silica sol, the silica content is 25-35%, the pH is 8.0-9.5, the alkaline silica sol is nano-scale silica sol, and the average particle size is not more than 20nm.

4. The acid and alkali resistant environment friendly inorganic paint according to claim 1, wherein the pigment and filler is at least one of quartz powder with mesh number of 500-1500 mesh, talcum powder, calcium carbonate, titanium pigment and barium sulfate.

5. The acid and alkali resistant environment friendly inorganic coating according to claim 1, wherein said thickener is aqueous polyamide wax, comprising the steps of:

S1, adding a heat stabilizing additive, aqueous polyamide wax slurry and an organic solvent into a reaction kettle, and heating to 125-130 ℃ until the heat stabilizing additive and the aqueous polyamide wax slurry are completely dissolved in the corresponding organic solvent;

6. The acid and alkali resistant environment-friendly inorganic coating is characterized in that the heat stable auxiliary agent is polyamide resin obtained by reacting monoacid and diamine, wherein the monoacid is at least one of n-octanoic acid, n-nonanoic acid, n-decanoic acid, lauric acid and 12-hydroxystearic acid, and the diamine is at least one of 4,4' -diamino dicyclohexylmethane, 3' -dimethyl-4, 4' -diamino dicyclohexylmethane and polyamine.

7. The acid and alkali resistant environment-friendly inorganic coating is characterized in that the organic solvent is at least one of propylene glycol n-propyl ether and propylene glycol monobutyl ether;

8. The acid and alkali resistant environment friendly inorganic paint according to claim 5, wherein the surfactant is at least one of fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether sodium sulfate, polyoxyethylnonylphenyl ether and alkyl aryl polyoxyethylene ether.

9. The acid and alkali resistant environment-friendly inorganic coating is characterized in that the alkali resistant dispersing agent is at least one of sodium lignin sulfonate and maleic acid-acrylic acid copolymer;

the water-increasing agent is sodium methyl siliconate.

10. A method for preparing the acid and alkali resistant environment-friendly inorganic coating as claimed in any one of claims 1 to 9, which is characterized by further comprising the following steps: