CN114752240A

CN114752240A - Method for preparing fireproof, waterproof and antibacterial film

Info

Publication number: CN114752240A
Application number: CN202210516974.XA
Authority: CN
Inventors: 沈建国; 潘浩明
Original assignee: Shenzhen Qiyou Water Paint Technology Co ltd
Current assignee: Shenzhen Qiyou Water Paint Technology Co ltd
Priority date: 2022-05-12
Filing date: 2022-05-12
Publication date: 2022-07-15

Abstract

The invention discloses a method for preparing a fireproof, waterproof and antibacterial film, which belongs to the technical field of wall paint production technology, and is characterized in that 50-200 parts of deionized water is added into a reaction kettle, and then 2% of thickening agent is added; respectively adding and stirring uniformly 75-300 parts of rutile titanium dioxide, 50-200 parts of flame retardant, 50-150 parts of talcum powder, 10-40 parts of dispersing agent and 5-20 parts of defoaming agent; then, deionized water is used for cleaning the inner wall of the reaction kettle, and then the pH value of the mixed solution is adjusted to be 8-9; continuously adding and uniformly stirring 160-760 parts of modified inorganic mineral ecological silicon resin, 50-200 parts of a mixture of the plant-based amino acid waterproof resin and the modified inorganic mineral ecological silicon resin, 100-200 parts of hydrophobic group elastomer waterproof material and 5-20 parts of propylene glycol; finally, 0.1 to 0.6 portion of polyurethane thickener is added; and stirring uniformly to obtain a finished product. The invention solves the technical problems of poor waterproof, fireproof and formaldehyde removing effects of the wall paint in the prior art.

Description

Method for preparing fireproof, waterproof and antibacterial film

Technical Field

The invention relates to the technical field of wall paint production technology, in particular to a method for preparing a fireproof, waterproof and antibacterial film.

Background

The development of the current economy promotes the improvement of the environmental awareness of people, and the environmental quality problem is widely concerned by people. At present, due to the use of a large amount of decoration materials, the life quality of people is improved, and meanwhile, the indoor air quality is continuously deteriorated. People are no longer limited to the antifouling and decorative properties of the traditional wall paint, and focus on factors such as low odor, harmlessness to human bodies and the like. Environmental concerns have also driven the paint technology to become green, and Volatile Organic Compounds (VOC) in paints have become increasingly restricted around the world. The VOC in the above is an English abbreviation of volatile organic compounds (VOLATILE ORGANIC COMPOUNDS). There are several good definitions, and the most common consensus holds that VOCs refer to those chemicals with boiling points below 250 ℃, i.e. those with boiling points above 250 ℃ do not fall into the category of VOCs. Therefore, formaldehyde common in life also belongs to the control range of VOC organic matters. Formaldehyde has been classified as one of the suspected carcinogens by the international center for cancer research because it is highly irritating to human skin, eyes and respiratory tract. Based on the above, chinese patent CN102618757A discloses an anti-mildew formaldehyde-removing paint, which comprises the following components (by weight): 100 parts of polystyrene-acrylic acid copolymer or polyacrylic acid copolymer or polyvinyl acetate-acrylic acid copolymer, 26-30 parts of talcum powder, 5-8 parts of auxiliary agent, 6-10 parts of pigment, 8-10 parts of mildew-proof bactericide, 3-5 parts of adsorbent and 40-50 parts of water, wherein the mildew-proof bactericide is a mixture of nano TiO2, nano ZnO and ZrO2, the particle sizes of nano TiO2 and nano ZnO are both 30-50 nanometers, the particle size of ZrO2 is-400 meshes, and the proportion of the three is TiO 2: ZnO: ZrO2 ═ 1-2: 1: 0.5. the mildew-resistant formaldehyde-removing coating disclosed above can effectively resist mildew, has a lasting effect, and simultaneously has a formaldehyde-removing effect.

However, the mildew-resistant formaldehyde-removing paint disclosed above also has the technical problem of poor formaldehyde-removing effect. Specifically, the mildew-resistant formaldehyde-removing paint mainly utilizes the function of adsorbing formaldehyde in the air by using the adsorbent contained in the mildew-resistant formaldehyde-removing paint. The adsorbent comprises one or more of bamboo charcoal, activated carbon, diatomite or perlite. Taking bamboo charcoal as an example, the coating mainly utilizes the adsorption mechanism of the bamboo charcoal. The bamboo charcoal molecular structure is hexagonal, has a hard, loose and porous structure, can effectively adsorb a part of floating substances in the air and harmful chemical substances and smell including formaldehyde, but the bamboo charcoal serving as a filler is usually added at a high-speed dispersion stage of paint preparation, the addition amount of the bamboo charcoal usually only accounts for less than 1% of the whole formula, and the stability and the continuity of the formaldehyde absorption effect of the bamboo charcoal can not be basically ensured; also, the bamboo charcoal has another disadvantage in that since the formaldehyde removing effect is based on physical adsorption rather than chemical reaction, once the total amount of formaldehyde adsorbed by the bamboo charcoal reaches saturation, the bamboo charcoal does not continue to act, and reversible desorption occurs over time, and a part of formaldehyde gas is released in turn. The action mechanism of other activated carbon, diatomite or perlite is similar to that of bamboo charcoal; there are also disadvantages of short persistence and poor stability. In addition, the above coating is improved in fire resistance, water resistance and the like.

Disclosure of Invention

Therefore, it is necessary to provide a method for preparing a fireproof, waterproof and antibacterial coating film for wall paint, which solves the technical problems of poor waterproof, fireproof and formaldehyde-removing effects of the wall paint in the prior art.

A method for preparing a fireproof, waterproof and antibacterial coating film comprises the following steps:

s1: firstly, adding 50-200 parts of deionized water into a reaction kettle, then adding 2% of thickening agent, and continuously stirring uniformly until the thickening agent is completely dissolved;

s2: respectively adding and stirring uniformly 75-300 parts of rutile titanium dioxide, 50-200 parts of flame retardant, 50-150 parts of talcum powder, 10-40 parts of dispersing agent and 5-20 parts of defoaming agent;

s3: then, 50-200 parts of deionized water is added along the edge of the reaction kettle to clean the inner wall of the reaction kettle, and the mixed solution in the reaction kettle is continuously stirred;

s4: then, adding 10-40 parts of neutralizing agent to adjust the pH value of the mixed solution to an interval of 8-9, and controlling the stirring speed to be 1500 revolutions per minute so as to control the particle fineness in the mixed solution to 8 mu m;

s5: continuously adding and uniformly stirring 160-760 parts of modified inorganic mineral ecological silicon resin, 50-200 parts of a mixture of the plant-based amino acid waterproof resin and the modified inorganic mineral ecological silicon resin, 100-200 parts of hydrophobic group elastomer waterproof material and 5-20 parts of propylene glycol;

s6: finally, 0.1 to 0.6 portion of polyurethane thickener is added; and stirring uniformly to obtain a finished product.

Specifically, the thickener is one or a mixture of HEUR, HE-10K, Bentone LT, TT935 or NHS 300.

Specifically, in step S2, the flame retardant is one or a mixture of two of a polycyanurate phosphate and a triazine char-forming agent.

Specifically, the mixing ratio of the polycyanamide phosphate to the triazine charring agent is 1: 4.

Specifically, in step S2, the talc powder is replaced with diatomaceous earth or silicate.

Specifically, in step S2, a wetting agent is added at the same time as the dispersant is charged, and the mass ratio of the wetting agent to the dispersant is 1: 1.

Specifically, in step S6, 3 to 6 parts of bactericide is added, then 0.1 to 0.6 part of polyurethane thickener is added, and finally, the mixture is stirred uniformly.

Specifically, the bactericide is a complex ligand of CMIT and MIT, wherein the mass ratio of the CMIT to the MIT is 1: 3.

in conclusion, according to the method for preparing the fireproof, waterproof and antibacterial coating, disclosed by the invention, the viscosity of deionized water is increased by adding 2% of the thickening agent, so that the subsequently added pigment, filler, flame retardant and the like have better shearing force in a certain viscosity state, the pigment, the filler, the flame retardant and the like can be rapidly dispersed to the required fineness, and the phenomena of sagging and the like of the coating during thick coating can be controlled. Then, adding rutile titanium dioxide as a pigment of the coating, so that the coated film has good covering power; then, talcum powder is added as a filler, so that a good filling line is formed in the film covering force, and the fullness, the drying property and the smoothness in construction of a paint film are improved. Then, adding a flame retardant to ensure that the coating film has good flame retardant performance; the flame retardant may be a mixture of melamine phosphate and triazine char-forming agent. Then, adding a dispersing agent to avoid the condition that pigments or fillers are aggregated into clusters due to water absorption; then, an antifoaming agent is further added to eliminate bubbles generated during stirring and to suppress generation of bubbles during construction. Then, 50-200 parts of deionized water is added to clean the reaction kettle, and then 10-40 parts of neutralizing agent is used to adjust the pH value of the solution to 8-9, so that the subsequent fineness of the particles is adjusted to 8 mu m at the rotating speed of 1500 revolutions per minute. Then, regulating the formaldehyde absorption performance of the coating film and improving the durability of the coating film by respectively modifying the inorganic mineral ecological silicon resin, the amino acid containing waterproof resin and the elastomer waterproof material; finally, the propylene glycol plays a role in preventing freezing. Therefore, the method for preparing the fireproof, waterproof and antibacterial coating film solves the technical problems of poor waterproof, fireproof and formaldehyde removing effects of the wall paint in the prior art.

Drawings

FIG. 1 is a flow chart of a method for preparing a fireproof, waterproof and antibacterial coating film according to the present invention;

FIG. 2 is a graph of absorbance versus formaldehyde concentration.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 1, fig. 1 is a flow chart of a method for preparing a fireproof, waterproof and antibacterial coating film according to the present invention. As shown in fig. 1, the method for preparing a fireproof, waterproof and antibacterial coating film of the present invention comprises the following steps:

s3: then, 50-200 parts of deionized water is added along the edge of the reaction kettle to clean the inner wall of the reaction kettle, and the mixed liquid in the reaction kettle is continuously stirred;

s4: then, adding 10-40 parts of neutralizer to adjust the pH value of the mixed solution to an interval of 8-9, and controlling the stirring speed to be 1500 revolutions per minute so as to control the particle fineness in the mixed solution to 8 mu m;

Specifically, the thickener is known as a rheological aid, and can thicken and thicken the paint, prevent sagging phenomenon in construction, and endow the paint with excellent mechanical properties and storage stability. The viscosity of the water paint is divided into low shear, medium shear and high shear viscosity. The viscosity under low shear mainly corresponds to the viscosity of the paint during storage and transportation in a tank; the high-shear viscosity corresponds to the construction viscosity of the coating under higher shear force during coating; the medium shear viscosity corresponds to the viscosity of the coating after the coating is constructed and when the coating flows on a wall, and each viscosity has specific application occasions. In a method for producing a flameproof, waterproof and antibacterial coating film of the present invention, it is preferable to use a rheological thickener having a strong associative property, such as polyurethanes or polyethers. The molecular side chain of the thickener contains a plurality of hydrophobic groups, and when the thickener is added into a system, the hydrophobic groups can be adsorbed with hydrophobic ends on the surfaces of particles, surfactants and even modified pigments and fillers in a solution to form a three-dimensional network structure, so that the thickening effect is achieved. More specifically, the present invention may use AQUAFLOW NHS 300 as a primary thickener, which is a polyurethane-type associative rheological thickener (HEUR); the thickening mechanism of the emulsion paint is from a strong association effect, so that the emulsion paint can keep higher viscosity when standing, and the viscosity of the system can be greatly reduced when larger shearing force is applied to the emulsion paint, so that the emulsion paint is convenient to construct, and is a good rheology modification auxiliary agent. The viscosity of the latex paint added with the rheological additive is reduced along with the increase of the shear rate, but the thickening agent belongs to Newtonian fluid, the rheological curve of the thickening agent is a horizontal straight line, and the leveling property and the fullness of a coating film can be improved besides the adjustment of the viscosity. However, such thickeners are greatly affected by various components in the system, the thickening response is poor when the particle size of the emulsion is increased, the association effect is easy to change along with the change of the hydrophilic-lipophilic balance (HLB) of the components in the system, so that the thickening efficiency is general when the thickeners are used alone, and the thickeners need to be matched with other thickeners, but the HEC is not recommended to be matched, so that the risk of coating delamination after storage can be brought. Thus, the following thickeners may be used: HE-10K, Bentone LT, TT935 or NHS 300, and the like.

Specifically, the pigment is a granular fine powder, the main function of the pigment is to color and cover a base material, and in addition, some pigments have the effects of shielding ultraviolet rays, improving the physical and chemical properties of a coating film and the like after being modified. Pigments fall into four main categories: white pigments, colored pigments, extender pigments and functional pigments. Generally, the pigment has a small particle size and is difficult to disperse uniformly in the system. The filler particle size is much larger in comparison, and the main purpose is to reduce the unit cost of the coating. Some fillers can also improve the defects of film coating such as cracking resistance, chalking resistance and the like according to different particle forms. The white pigment in the paint is mainly titanium dioxide. The refractive index of the powder which can be used as the pigment is not less than 1.7, the titanium dioxide can be divided into a rutile type and an anatase type due to the difference of crystalline states, the refractive index of the former is about 2.72, the refractive index of the latter is about 2.55, and the refractive index of the deionized water mixed with the thickener used as the base material is about 1.5, so the refractive index of the powder is more than 1.5, the covering capability of the powder is stronger, and the covering capability of the rutile type titanium dioxide is stronger than that of the anatase type. In addition, because the two titanium white have different crystal forms, the powdering resistance and the light stability of the two titanium white are different, the rutile type titanium white has better stability, and the anatase type photocatalysis effect is stronger. The rutile titanium dioxide is used in the method for preparing the fireproof, waterproof and antibacterial coating, for example, the rutile titanium dioxide such as DuPont R902+ can be used, and the titanium dioxide white pigment has narrower particle size distribution, so that higher glossiness, super weather resistance and excellent dispersibility can be brought to the coating.

Furthermore, for the filler, although the whiteness of the powder is higher under naked eyes, and the blue light whiteness of some powder is even higher than that of titanium dioxide, the paint film of the filler is still transparent after being completely dried and is almost the same as that of a varnish film without the filler, because the refractive index of most of the filler is 1.5-1.6, the filler cannot directly contribute to the covering power of the paint film. Some of the fine-particle fillers, which are aluminum silicate compounds synthesized by precipitation and calcined natural kaolin, also contain aluminum silicate as a main component, act to help disperse and grind the titanium white and increase the usage rate of the titanium white, thereby indirectly affecting the hiding performance of the coating film, such as Zeolex323 and MXK 201. Therefore, most titanium dioxide products are coated with Al2O3, SiO2, etc. on the particle surface, and are also organically modified with silane, etc., all of which are intended to improve the dispersibility and utilization rate of titanium dioxide. Diatomaceous earth and silicates have a large oil absorption and their amount should be controlled as fillers. Because the main body of the pigment is titanium dioxide, the effects of improving the covering and increasing the whiteness are achieved; the addition of a little talc may help the grinding dispersion during the beating stage. Wherein, the calcium carbonate component contained in the talcum powder not only serves as a grinding agent of the rest powder, but also can be matched with pigment to form a 'skeleton' of the coating film. Furthermore, it is also possible to use diatomaceous earth and silicates as an alternative to talc.

Furthermore, after the pigment and the filler are added in the method for preparing the fireproof, waterproof and antibacterial coating film, a dispersing agent and a defoaming agent are further added. The dispersion of the pigment can be broken down into 3 interrelated steps: 1. wetting: namely, the pigment dispersant is used for replacing water and air which are originally adsorbed on the pigment aggregate; 2. separation: applying shearing force to the grinding material to separate pigment aggregate and restore to a primary particle state; simultaneously wetting the separation surface formed by the separation with a pigment dispersant; 3. and (3) stabilizing: that is, the pigment dispersant is adsorbed on the pigment surface after wetting the pigment surface, to stabilize the dispersion. Because the dispersion medium of the invention is deionized water, and the surface tension of water is 72.8mN/m, which is about 2-4 times of that of various solvents in the oil paint, the pigment and filler which are enough to be fully soaked in the solvent at ordinary times can be fully moistened by adding an additional wetting agent into the water, because the wetting agent can penetrate into surface gaps of pigment and filler particles and replace air, and the dispersing agent has the function of uniformly and stably dispersing solid phases of small particles in a liquid phase, so that the small particles are prevented from being agglomerated into large particles due to the action of mutual interaction force to induce sedimentation. Therefore, in the present invention, a wetting agent can be further added in combination with a dispersant to further improve the dispersibility of the particles in the solution, for example, CF-10 can be added as the wetting agent, and the ratio of the wetting agent to the dispersant is: 1:1. Further, SN-5040 of Nopocidae is a polyacrylic acid sodium salt anionic dispersant which has two mechanisms of dispersing and stabilizing pigments and fillers, and one mechanism is a charge stabilizing mechanism: when the pigment/filler particles are added into a system, the pigment/filler particles can be tightly adsorbed on the pigment/filler particles, and meanwhile, the hydrophilic carboxylate radicals point to the water phase, so that the surfaces of the pigment/filler particles are provided with a negative charge layer, and as the pigment/filler particles are provided with the same charges and are close to each other, charge repulsion is generated, thereby playing a role in stabilizing and preventing agglomeration. Another mechanism is steric repulsion: as the main chain of the dispersant is a macromolecule, the macromolecule chain occupies a certain space when rotating, and the occupied space is in direct proportion to the molecular weight and the chain length. Pigment particles typically 8nm in size are attached to a 15nm long polymer chain dispersant, which can exclude a steric bulk of 120 nm. Generally, the dispersants are mostly polyacrylates, and are mainly divided into two types, namely sodium salts and ammonium salts. In addition to the fact that ammonium salts are slightly darker in color and slightly odorous, ammonium salts are also slightly less effective in dispersion than sodium salts, but have slightly improved water resistance of the coating film as compared with sodium salt dispersants. When the pigment and filler are in the formula, the optimal dosage of the dispersant can be determined: the viscosity of the system is gradually reduced along with the continuous addition of the dispersing agent, but when the dispersing agent is added to a certain degree, the viscosity is not reduced and is reversely increased, and the inflection point is the optimal dosage point of the dispersing agent. Based on this principle, experiments can be designed to determine the optimum amount of dispersant: according to the adding steps before the grinding stage in the formula, all fillers and auxiliaries except the dispersing agent are sequentially added and dispersed for 5min at a high speed, the initial viscosity of the mixture is measured by a brookfield viscometer, then the dispersing agent is gradually and slowly added in an equivalent manner, the dispersion is carried out for 5min every time when the amount of the dispersing agent is increased, the viscosity data of each time is recorded, a trend curve that the viscosity changes along with the increase of the dispersing agent is drawn, when the amount of the dispersing agent is increased to the lowest point in the curve of the viscosity measured at a certain point, the amount represents the optimal required amount of the dispersing agent by the pigments and fillers in the formula system, the adding amount of the dispersing agent in the formula can be 2-4 times of the optimal required amount, and detailed experimental data are shown in the following table 1:

table 1: effect of dispersant dosage on viscosity of film coating

Based on the above, the content of the dispersant is finally determined to be 0.5 percent of x (2-8) ═ 1-4 percent of the whole formula; that is, 10 to 40 parts of a dispersant may be added to 1000 parts of the total components.

Further, the presence of foam affects both the decorative effect and the overall performance of the film. The water paint prepared by the invention is a mixed system, various components which are easy to foam exist in the system, such as a dispersing agent in a solution, and the components are easy to foam the water paint, the surfactant can be adsorbed on a foam liquid film to form an electric double layer to play a foam stabilizing effect, and an associated thickening agent in the paint can thicken the foam liquid film, so that the defoaming is not facilitated. In addition, the high-speed dispersion of the coating in the pulping stage and the high-speed shearing force applied to the coating in the construction process to mix a large amount of air are also one of the main causes of the generation of a large amount of pores in the coating film. The foaming agents are various in kind, and mineral oils, silicones, metallic soaps, etc. are common. Mineral oil defoamers have very few active ingredients (< 5%), still suffer from poor defoaming properties due to their low surface tension and their incompatibility with water, which is the main contributor to the defoaming action. The silicone and metal soap defoaming agents are generally in an emulsified state, and although the compatibility with the system is improved, the defoaming effect is reduced. Due to the hydrophobicity of silicon, when the silicon modified defoaming agent is added into a coating, although the defoaming performance is good, adverse effects such as film shrinkage, edge shrinkage and the like can be caused, and the emulsified organosilicon modified defoaming agent has both defoaming performance and compatibility. The invention selects a Pasteur Foamstar series defoaming agent which has excellent defoaming performance, and the series active substances are a cluster of star-shaped macromolecules with high branching degree, and the invention is characterized in that the active substances can quickly permeate into a liquid film of foam to capture the hydrophobic end of the foam, so that the liquid film generates local surface tension difference to cause imbalance among internal stresses of the foam, thereby finally thinning and cracking the liquid film.

Further, an intumescent flame retardant may be used in a method of preparing a fire-proof, water-proof, and antibacterial coating film of the present invention. The intumescent flame retardant mainly comprises an acid source, a carbon source and a gas source, wherein the acid source mainly plays a role in dehydration and catalytic carbonization; the carbon source is generally a multi-light base compound with high carbon content, and mainly has the function of generating a crusted reaction with a product decomposed by the acid source and dehydrating to generate a nonflammable porous carbon layer in the combustion process; the gas source is noncombustible or inert gas which can inhibit flame from continuously spreading when heated at high temperature, and water vapor generated in the dehydration and carbon formation process of the acid source and the carbon source can promote the expansion of the carbon layer and promote the continuous expansion of the polymer to finally form the expanded carbon layer. Specifically, melamine phosphate (MPP) can be used as both an acid source and a gas source in an intumescent flame retardant system; it has the advantages of good thermal stability, small smoke generation amount, good dispersibility and the like. MPP can generate acid and then catalyze into charcoal when burning, releases the ammonia simultaneously and dilutes the concentration of oxygen in the air. The triazine charring agent (CFA) can be used as a charcoal source and an air source, has certain water resistance, and has the characteristics of high flame retardant efficiency and small influence on physical and mechanical properties, so that the triazine charring agent can play a role in synergistic flame retardant by being compounded with the acid source. Furthermore, the flame retardant performance test of the coating prepared by the method for preparing the fireproof, waterproof and antibacterial film coating is carried out by adding MPP/CFA flame retardants with different proportions, and the flame retardant performance of the film coating is found to be optimal when the mass ratio of MPP to CFA is 1: 4. Due to the addition of MPP/CFA, the coating is promoted to form a more continuous and compact carbon layer structure after combustion, ammonia gas is released to dilute the concentration of oxygen, and the MPP/CFA flame retardant coating plays a role in both physical flame retardance and chemical flame retardance.

Specifically, the flame retardant property of the sample is judged by adopting a limiting oxygen index test and a vertical burning test. The limit oxygen index test refers to the corresponding oxygen volume fraction when the test sample just burns to 40mm position 2min after being ignited according to the related definition of GB/T5454-1997, namely the limit oxygen index of the sample, and five groups of data of each group of samples are tested and averaged. The size of the film coating sample was 150mmX58 mm. The vertical burning test refers to the test of the material according to the relevant definition of the standard GB/T8626-2012, the burning phenomenon is observed, the burning time is recorded and the average value is taken, each group of samples is tested for at least 5 times, and the size of the film coating sample is as follows: 250mmX90 mm. The following table 2 shows the combustion test and the limiting oxygen index test of the flame retardant coating. In the test, except for the mixture ratio of the flame retardant, the other components are the component mixture ratio disclosed by the invention.

Table 2: test data of combustion test and limited oxygen index test of flame-retardant laminating coating

Specifically, as can be seen from the data in table 2, the film coating without the flame retardant is inflammable, requires only 46s of flame height to reach 150mm, and is dropped off during combustion to ignite the filter paper, and LOI (english abbreviation for limiting oxygen index) is 22%, thus having a fire risk. After MPP and CFA are added in the preparation of the film coating, the time of the flame height reaching 150m and LOI are obviously improved when the coating is combusted, and the flame does not fall off to ignite the filter paper in the combustion process. When the addition amounts of the MPP and the CFA are respectively 1 wt.% and 4 wt.%, the time of the flame height reaching 150mm when the coating burns is prolonged to 150s, meanwhile, the LOI is 25%, the flame-retardant effect of the flame-retardant coating reaches the best, and at the moment, the MPP and the CFA have the best synergistic effect, so that the flame-retardant performance of the coating can be effectively improved.

Further, respectively adding a pigment, a filler, a dispersing agent, a defoaming agent and a flame retardant; then 50-200 parts of deionized water are slowly added along the inner wall of the reaction kettle to clean the inner wall of the reaction kettle. Firstly, the powder which is adhered to the inner wall and is not dissolved can be mixed into the solution, and secondly, the dissolution rate of respective particles in the solution can be adjusted by adding deionized water. In addition, 10-40 parts of neutralizing agent is further added to adjust the pH value of the solution to 8-9, namely a slightly alkaline state, so that the fineness of particles in the solution can be adjusted to about 8 mu m in the subsequent high-speed stirring of 1500 revolutions per minute.

Further, 760 portions of modified inorganic mineral ecological silicon resin and 50-200 portions of mixture of the plant-based amino acid waterproof resin and the modified inorganic mineral ecological silicon resin are added and stirred evenly; the plant-based amino acid waterproof resin and the modified inorganic mineral ecological silicon resin are mixed and reacted to generate the compound for protecting the alkaloid. The alkaloids are a class of nitrogen-containing organic compounds that occur widely in nature. The molecular structure of the compound contains-NH₂or-NH₂Reactive groups which convert formaldehyde into non-toxic substances by nucleophilic addition reaction with formaldehyde. The reaction mechanism for removing formaldehyde is shown in formula 1 and formula 2:

formula 1: HO^-+H-N-R→H₂O+：N-R；

Formula 2:

further, the coating prepared by the method for preparing the fireproof, waterproof and antibacterial coating is subjected to formaldehyde absorption performance test, specifically, 70g of coating to be tested is uniformly coated on a glass plate with the square meter of 1 m by reference to JC/T1074-2008 standard detection, and the coating is maintained for 7 days in a constant temperature and humidity room. The glass plates were then placed in a 1 cubic meter glass chamber and tested after injection of 3 μ L of analytically pure formaldehyde and sealing for 1 hour. Preparing a formaldehyde standard solution according to GB/T16129-1995, preparing 10 standard color tubes according to table 3, and preparing an absorbance-formaldehyde concentration curve by taking the formaldehyde content as an abscissa and the absorbance as an ordinate; i.e. as shown in fig. 2. Collecting the gas in the sampling glass cabin by using a bubble absorption tube with absorption liquid, and calculating the concentration of formaldehyde in the sample gas by comparing the absorbance of the gas with that of the pure absorption liquid, wherein the concentration of formaldehyde in the sample gas is as follows 3:

formula 3:

and then comparing with a blank glass cabin without a brush-coated glass plate, substituting the value c obtained by the formula into the value c to calculate the net aldehyde efficiency of the coating, wherein the value c is as follows in formula 4:

formula 4:

in the above formula:

a is absorbance of the sample solution;

a0-absorbance of reagent blank solution;

bg is a calculation factor, and the reciprocal of the slope of a curve of absorbance-formaldehyde concentration;

v0 — sample volume under standard conditions;

v1-volume of absorption solution at sampling;

v2 — sample volume at assay;

c-concentration of formaldehyde in air;

c 0-comparison of measured formaldehyde end concentration in the chamber;

c 1-end concentration of Formaldehyde as measured by the sample chamber.

Specifically, in order to test the formaldehyde resistance of the paint formulation, a formaldehyde standard concentration curve needs to be drawn according to JC/T1074-2008, and first, a formaldehyde pure solution with each standard concentration needs to be prepared, and the results are shown in table 3 below:

table 3: preparation of standard curve of formaldehyde concentration

Secondly, the respective absorbance of the formaldehyde solution is tested according to the formaldehyde pure solution with different concentrations, a standard curve of the formaldehyde concentration is drawn, then the concentration of the residual formaldehyde in the sample chamber is reversely deduced according to the absorbance after the residual formaldehyde in the sample chamber reacts with the absorption liquid during the formaldehyde removal test, so that the formaldehyde removal effect of the formaldehyde-resistant coating is obtained, and the results are shown in fig. 2 and table 4:

table 4: formaldehyde decomposition efficiency test meter

Concentration (μ g/5.4ml)	Absorbance (A)
		0.0	0.130
0.1	0.160
		0.2	0.166
0.4	0.189
		0.6	0.237
0.8	0.272
		1.0	0.284
1.5	0.381
		2.0	0.458
2.5	0.550

Preparing the anti-formaldehyde emulsion prepared in the above into a coating paint sample according to a preset adding proportion, and then preparing the coating paint sample according to the preset adding proportion

JC/T1074-2008 standard for testing results are shown in Table 5 below:

table 5: formaldehyde removal performance chart

Therefore, the film coating prepared by the method for preparing the fireproof, waterproof and antibacterial film coating can effectively adsorb and remove free formaldehyde in air, and the formaldehyde adsorption treatment efficiency can reach 92.04%.

Furthermore, the wall paint prepared by the method for preparing the fireproof, waterproof and antibacterial coating film is an aqueous system, so that the wall paint is easy to become a hotbed for breeding microorganisms, and a proper amount of sterilization and mildew preventive is necessary to be added in the formula. The water paint can be added with a formaldehyde releasing agent to play a role in-can corrosion prevention, but the introduction of formaldehyde as a formaldehyde-resistant coating for sterilization is obviously the behavior of inversion at the end and does not meet the current environmental protection requirement. Therefore, the bactericide used in the invention is isothiazolinone, which is a common broad-spectrum bactericide, and is classified into BIT, CMIT, MIT, and the like. BIT is 1, 2-benzisothiazolin-3-one, and has the advantages of stable structure, heat resistance, poor mildew resistance and general sterilization effect; MIT is 2-methyl-4-isothiazolin-3-one, and the bactericidal effect is stronger than BIT; and CMIT replaces 1 chlorine atom on MIT, make originally already more excellent sterilization performance increase by a factor, but also make stability and persistence reduce greatly, so CMIT often and MIT are used to match and can make up for each other's deficiencies, the most suitable compounding ratio is CMIT: MIT 1: 3. in order to achieve excellent bactericidal effect, a coating formula generally combines a plurality of bactericides, but even if the types of the bactericides are wider and the dosage is insufficient, the bactericidal effect is difficult to achieve. Each bacterium has its own Minimum Inhibitory Concentration (MIC) for each bactericide, and is effective for sterilization only when the concentration of the bactericide in the system is higher than the MIC of the bactericide to be sterilized. Both THOR' ACTICIDEMV and ACTICIDEMBS are common bactericides for aqueous systems and are suitable for both synthetic resin emulsions and latex paint systems. The former is a CMIT/MIT complex ligand, and the application range is that the pH value is 2-9 and the temperature is below 60 ℃; the main component of the latter is BIT, and the using condition is wider, the pH value is 2-10, and the temperature is below 80 ℃. The bactericide mainly plays a role in protecting the coating in a tank when the coating is in a liquid state, the mildew preventive protects the coating from being damaged by mildew after construction and film forming, and a plurality of mildew preventives can be used as pesticides, such as swertia alata and the like. The main component of the ACTICIDEOTW is 4, 5-dichloro-2-n-octyl-4-isothiazolin-3-ketone (DCOIT), and the active component of the ACTICIDEOTW can inhibit the activity of enzyme in the mould, block the breathing of the mould and play a role in preventing the mould. Therefore, the present invention may further include 3-6 parts of a bactericide, which is a complex ligand of CMIT/MIT, in step S6, wherein the ratio of CMIT: MIT 1: 3.

further, 100-200 parts of hydrophobic group elastomer waterproof material and 5-20 parts of propylene glycol are continuously added. The hydrophobic group elastomer waterproof material can enhance the waterproof performance of a coated film, and the waterproof principle of the polymer water paint waterproof coating is to form a flat and compact waterproof coated film on the surface of a protected material to prevent the invasion of water vapor and the penetration of moisture. The film forming principle of the waterproof coating is as follows: the polymer solution, the filler and the dispersion system are uniformly mixed and then coated on the surface of a base material, particles in the solution and the solid powder filler gradually approach and squeeze along with the evaporation of water to slowly form a closely packed coating, the water is further volatilized under the action of capillary pressure, the gaps between the solid powder filler and the particles in the emulsion are further reduced, and finally a dense and smooth waterproof coating is formed. For example, the silicone containing silicon oxygen group can be selected according to the invention, and the silicone has the characteristics of excellent hydrophobicity, coloring resistance, chemical resistance and the like, and the organic fluorine compound has excellent thermal stability, weather resistance and corrosion resistance. By using the organic fluorine modified acrylic resin, the coating not only has the acid and alkali resistance of the acrylic resin, but also has the advantages of light retention, hydrophobicity and the like. Specifically, the self-stratifying coating is prepared by blending the fluorosilicone modified acrylic resin and the synthetic polyurethane modified epoxy resin, when the mass ratio of the two resins is 1:1, the contact angle of the coating reaches 96 degrees, the flexibility is 0.5mm, the impact resistance is 50cm, the adhesive force grade is first grade, the light loss rate is reduced to 19%, and the self-stratifying coating has excellent aging resistance and corrosion resistance. Furthermore, the dispersion medium of the water-based paint is deionized water, if the water-based paint is transported and stored in a cold area in northern China, the freezing phenomenon is easy to generate, in order to ensure the low-temperature stability of the water-based paint, a proper amount of antifreeze is generally added to reduce the freezing point of the whole system, and the empirical formula of the freezing point temperature reduction is about 1.855mi which is the molar concentration of the added antifreeze. Common antifreeze agents are ethylene glycol and propylene glycol, the latter being more environmentally friendly. Thus, 5 to 20 parts of propylene glycol are selected as antifreeze in the present invention. Finally, continuously adding 0.1-0.6 part of polyurethane thickener; and then stirring uniformly to obtain a finished product.

In conclusion, according to the method for preparing the fireproof, waterproof and antibacterial coating film, disclosed by the invention, the viscosity of deionized water is increased by adding 2% of the thickening agent, so that the subsequently added pigment, filler, flame retardant and the like have better shearing force in a certain viscosity state, the pigment, the filler, the flame retardant and the like can be rapidly dispersed to the required fineness, and the phenomena of sagging and the like of the coating during thick coating can be controlled. Then, adding rutile titanium dioxide as a pigment of the coating, so that the coated film has good covering power; then, talcum powder is added as a filler, so that a good filling line is formed in the film covering force, and the fullness, the drying property and the smoothness in construction of a paint film are improved. Then, adding a flame retardant to ensure that the film has good flame retardant property; the flame retardant may be a mixture of melamine phosphate and triazine char-forming agent. Then, adding a dispersing agent to avoid the condition that the pigment or the filler and the like are aggregated into a mass due to water absorption; then, an antifoaming agent is further added to eliminate bubbles generated during stirring and to suppress generation of bubbles during construction. Then, 50-200 parts of deionized water is added to clean the reaction kettle, and then 10-40 parts of neutralizing agent is used to adjust the pH value of the solution to 8-9, so that the fineness of the particles can be adjusted to 8 μm at the rotation speed of 1500 revolutions per minute. Then, regulating the formaldehyde absorption performance of the coating film and improving the durability of the coating film by respectively modifying the inorganic mineral ecological silicon resin, the amino acid containing waterproof resin and the elastomer waterproof material; finally, the propylene glycol plays a role in preventing freezing. Therefore, the method for preparing the fireproof, waterproof and antibacterial coating film solves the technical problems of poor waterproof, fireproof and formaldehyde removing effects of the wall paint in the prior art.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A method for preparing a fireproof, waterproof and antibacterial film is characterized by comprising the following steps:

2. The method for preparing a flameproof, waterproof, and antibacterial coating film according to claim 1, characterized in that: the thickener is one or a mixture of HEUR, HE-10K, Bentone LT, TT935 or NHS 300.

3. The method for preparing a flameproof, waterproof, and antibacterial coating film according to claim 1, characterized in that: in step S2, the flame retardant is one or a mixture of two of a polycyanurate phosphate or a triazine char-forming agent.

4. The method for preparing a flameproof, waterproof, and antibacterial coating film according to claim 3, characterized in that: the mixing ratio of the polycyanamide phosphate to the triazine charring agent is 1: 4.

5. The method for preparing a flameproof, waterproof, and antibacterial coating film according to claim 1, characterized in that: in step S2, the talc is replaced with diatomaceous earth or silicate.

6. The method for preparing a flameproof, waterproof, and antibacterial coating film according to claim 1, characterized in that: in step S2, a wetting agent is added at the same time as the dispersant is charged, and the charging mass ratio of the wetting agent to the dispersant is 1: 1.

7. The method for preparing a flameproof, waterproof, and antibacterial coating film according to claim 1, characterized in that: in step S6, 3 to 6 parts of bactericide is added, then 0.1 to 0.6 part of polyurethane thickener is added, and finally, the mixture is stirred uniformly.

8. The method for preparing a flameproof, waterproof, and antibacterial coating film according to claim 7, characterized in that: the bactericide is a complex ligand of CMIT and MIT, wherein the mass ratio of the CMIT to the MIT is 1: 3.