Attapulgite reinforced functional coating and preparation method thereof

Abstract

The application relates to the technical field of fireproof weather-resistant coatings, and discloses a functional coating reinforced by attapulgite and a preparation method thereof, specifically: synthesizing an ultraviolet absorption type flame-retardant coupling monomer; modifying the ultraviolet absorption type flame-retardant coupling monomer on the surface of attapulgite through a phosphorus hydroxyl-hydroxyl condensation reaction to obtain ultraviolet absorption type flame-retardant attapulgite; and compounding the ultraviolet absorption type flame-retardant attapulgite as a functional modification component with film-forming resin, bulk fillers and other auxiliaries to prepare the functional coating reinforced by attapulgite; the coating product shows excellent fireproof performance and weather-resistant performance, meets the technical requirements stipulated in the GB 14907-2018 'Steel Structure Fireproof Coating' standard, and has relatively excellent comprehensive performance, and can be used as an outdoor steel structure building fireproof coating.

Description

Technical Field

[0001] This invention relates to the field of fire-retardant and weather-resistant coating technology, specifically to an attapulgite-reinforced functional coating and its preparation method. Background Technology

[0002] Steel structure buildings are widely used in high-rise buildings and large factories in my country due to their advantages such as high strength and fast construction speed. However, steel structure buildings have extremely poor fire resistance, and their mechanical strength decreases rapidly with increasing temperature. When the critical temperature (usually 500-600℃) is reached, they may even collapse, posing a serious threat to people's lives and property.

[0003] Fire-retardant spray coatings have become the preferred method for fire protection of steel structure buildings due to their advantages such as simple construction and low cost. Adding flame retardants to the coating formulation is one of the important technical routes for preparing fire-retardant coatings. However, directly added flame retardants are prone to migration to the coating surface under temperature fluctuations (such as outdoor exposure to sunlight or high temperatures in industrial environments) due to molecular diffusion or compatibility issues. Consequently, they are lost with the medium under the action of external environmental erosion (rainwater, moisture, industrial wastewater), resulting in poor fire resistance of the fire-retardant coating.

[0004] Research has found that fixing flame retardants onto inorganic fillers helps improve the fire resistance failure of fire-retardant coatings caused by flame retardant loss. Attapulgite, a common and inexpensive inorganic filler, is abundant. Its textured crystal surface, porous structure, and strong adsorption properties can also act as a suspending and thickening agent, preventing sedimentation and sagging during storage and application.

[0005] In addition, fireproof coatings on the exterior walls of steel structure buildings need to be exposed to the outdoors for a long time, which makes them susceptible to the effects of ultraviolet radiation, resulting in phenomena such as peeling, cracking and color difference on the surface. There are reports in the existing technology of improving the weather resistance of coatings by adding ultraviolet absorbers. Summary of the Invention

[0006] This invention develops and synthesizes a UV-absorbing flame-retardant coupling monomer containing multiple flame-retardant elements (phosphorus, nitrogen, silicon, sulfur) and a hydroxybenzophenone structure (possessing strong UV absorption capability). This monomer is grafted onto the surface of attapulgite through chemical bonding, thereby preparing an attapulgite-reinforced functional coating. This coating product exhibits excellent fire resistance and weather resistance, and meets the technical requirements specified in GB 14907-2018 "Fireproof Coatings for Steel Structures" standard.

[0007] A method for preparing an attapulgite-reinforced functional coating includes the following steps:

[0008] Step 1: Graft the UV-absorbing flame-retardant coupling monomer onto the surface of attapulgite through a phosphorus hydroxyl-hydroxyl condensation reaction to obtain UV-absorbing flame-retardant attapulgite.

[0009] The ultraviolet-absorbing flame-retardant coupling monomer is ultraviolet-absorbing flame-retardant coupling monomer I or ultraviolet-absorbing flame-retardant coupling monomer II;

[0010] Step 2: Use UV-absorbing flame-retardant attapulgite as a functional modifier to combine with film-forming resin, extender filler and other additives to prepare attapulgite-reinforced functional coating.

[0011] Preferably, the preparation method of the ultraviolet-absorbing flame-retardant coupling monomer I is as follows:

[0012] In the presence of a photoinitiator, intermediate I-a is generated by a click reaction between the alkenyl functional group of 1 molar equivalent vinylpentamethyldisiloxane and the mercapto functional group of 1.01-1.09 molar equivalent 4-aminobenzylthiophenol under ultraviolet light.

[0013] Intermediate I-b is generated by an amino-enyl addition reaction between the -NH2 functional group of 1 molar equivalent intermediate I-a and the α,β-alkenyl functional group of 0.91-0.99 molar equivalent of 2-hydroxy-4-acryloyloxyethoxybenzophenone.

[0014] Based on the Kabachnik-Fields reaction mechanism, UV-absorbing flame-retardant coupling monomer I is generated through a condensation reaction of intermediate I-b, diethyl phosphite, and paraformaldehyde.

[0015] Preferably, the preparation method of the ultraviolet-absorbing flame-retardant coupling monomer II is as follows:

[0016] In the presence of a photoinitiator, intermediate II-a is generated by a click reaction between the alkenyl functional group of 1 molar equivalent vinylheptaisobutyl POSS and the thiol functional group of 1.01-1.09 molar equivalent 4-aminobenzylthiophenol under ultraviolet light.

[0017] Intermediate II-b is generated by an amino-enyl addition reaction between the -NH2 functional group of 1 molar equivalent intermediate II-a and the α,β-alkenyl functional group of 0.91-0.99 molar equivalent 2-hydroxy-4-acryloyloxyethoxybenzophenone.

[0018] Based on the Kabachnik-Fields reaction mechanism, UV-absorbing flame-retardant coupling monomer II is generated through a condensation reaction of intermediate II-b, diethyl phosphite, and paraformaldehyde.

[0019] Preferably, the photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone.

[0020] Preferably, the mass ratio of the ultraviolet-absorbing flame-retardant coupling monomer to the attapulgite in the ultraviolet-absorbing flame-retardant attapulgite is 1:(0.5-2).

[0021] The formulation of an attapulgite-reinforced functional coating prepared according to the above method is as follows: 15-25 parts by weight of water, 40-50 parts by weight of film-forming resin, 15-20 parts by weight of extender filler, 10-15 parts by weight of UV-absorbing flame-retardant attapulgite, and 5-10 parts by weight of composite additives.

[0022] Preferably, the film-forming resin is one or a combination of two of pure acrylic emulsion and styrene-acrylic emulsion.

[0023] Preferably, the filler is one or a combination of two of talc, barium sulfate, and calcium carbonate.

[0024] Preferably, the composite additive includes wetting agents, dispersants, defoamers, leveling agents, and thickeners.

[0025] Beneficial effects:

[0026] Based on the principle of molecular design, this invention uses vinylsiloxane monomers (vinylpentamethyldisiloxane or vinylheptaisobutyl POSS), 2-hydroxy-4-acryloyloxyethoxybenzophenone (UV absorber UV-2098), diethyl phosphite, and paraformaldehyde as raw materials to synthesize UV-absorbing flame-retardant coupling monomers through alkenyl-thiol click reaction, alkenyl-amino addition reaction, and Kabachnik-Fields reaction.

[0027] UV-absorbing flame-retardant coupling monomers were modified onto the surface of attapulgite through a phosphorus hydroxyl-hydroxyl condensation reaction to obtain UV-absorbing flame-retardant attapulgite.

[0028] Attapulgite-reinforced functional coatings are prepared by compounding UV-absorbing flame-retardant attapulgite as a functional modifier with film-forming resin, extender filler and other additives. The coatings have excellent fire resistance and weather resistance and can be used as fireproof coatings for outdoor steel structure buildings. Detailed Implementation

[0029] Experimental Example 1:

[0030] The preparation process of UV-absorbing flame-retardant coupling monomer I is as follows:

[0031] Process 1: In the presence of a photoinitiator, a click reaction occurs between the alkenyl functional group of 1 molar equivalent of vinylpentamethyldisiloxane (CAS No. 1438-79-5) and the mercapto functional group of 1.03 molar equivalent of 4-aminobenzenethiophenol under ultraviolet light, generating intermediate I-a, whose chemical structural formula is as follows:

[0032] ;

[0033] The photoinitiator can be selected from one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone; in this experimental example, 2,2-dimethoxy-2-phenylacetophenone was selected.

[0034] Process 2: An amino-enyl addition reaction occurs between the -NH2 functional group of 1 molar equivalent intermediate I-a and the α,β-alkenyl functional group of 0.94 molar equivalent 2-hydroxy-4-acryloyloxyethoxybenzophenone (UV absorber UV-2098), generating intermediate I-b, whose chemical structural formula is as follows:

[0035] ;

[0036] Process 3: Based on the Kabachnik-Fields reaction mechanism, a condensation reaction occurs between intermediate I-b, diethyl phosphite, and paraformaldehyde to generate UV-absorbing flame-retardant coupling monomer I, whose chemical structural formula is as follows:

[0037] ;

[0038] The specific experimental steps for preparing UV-absorbing flame-retardant coupling monomer I are as follows:

[0039] Under nitrogen protection, 3.5 g of vinylpentamethyldisiloxane, 0.1 g of 2,2-dimethoxy-2-phenylacetophenone, and 40 mL of anhydrous tetrahydrofuran were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, under UV irradiation (360 nm, 10 cm), 20 mL of 4-aminothiophenol solution (prepared from 2.6 g of 4-aminothiophenol and 20 mL of anhydrous tetrahydrofuran) was added dropwise to the three-necked flask. After the addition was complete, the reaction was stirred under UV irradiation for 60 min. The solvent was removed by rotary evaporation, and the product was washed with anhydrous ethanol and dried to obtain intermediate I-a.

[0040] 3.0 g of intermediate I-a and 30 mL of anhydrous tetrahydrofuran were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 30 mL of 2-hydroxy-4-acryloyloxyethoxybenzophenone solution (prepared from 2.9 g of 2-hydroxy-4-acryloyloxyethoxybenzophenone and 30 mL of anhydrous tetrahydrofuran) was added dropwise to the three-necked flask. The mixture was stirred at room temperature for 30 min, heated to 60 °C and stirred for 8 h, cooled to room temperature, and the solvent was removed by rotary evaporation. After drying, intermediate I-b was obtained.

[0041] Under nitrogen protection, 3.1 g of intermediate I-b, 0.7 g of diethyl phosphite, 20 mL of anhydrous tetrahydrofuran and 10 mL of anhydrous ethanol were added to a three-necked flask, stirred and mixed at room temperature for 30 min, heated to 70 °C and stirred for 4 h, cooled to room temperature, the solvent was removed by rotary evaporation, washed with anhydrous ethanol and dried to obtain UV-absorbing flame-retardant coupling monomer I.

[0042] The proton NMR spectrum characterization of UV-absorbing flame-retardant coupling monomer I is as follows: 1 H NMR (CDCl3, 400MHz) δ: 0.02(s, 6H), 0.07(s, 9H), 0.96-0.99(t, 2H), 1.34-1.38(t, 6H), 2.55-2.58(t, 2H), 2.88-2.91(t, 2H), 3.65-3.68(t, 2H), 3.99-4.02(d, 2H), 4.18-4.26(m, 6H), 4.34-4.37(t, 2H), 6.55-7.73(m, 12H).

[0043] Experimental Example 2:

[0044] The preparation process of UV-absorbing flame-retardant coupling monomer II is as follows:

[0045] Process 1: In the presence of a photoinitiator, a click reaction occurs between the alkenyl functional group of 1 molar equivalent of vinylheptaisobutyl POSS (CAS No. 444315-18-8) and the thiol functional group of 1.03 molar equivalent of 4-aminobenzylthiophenol under ultraviolet light, generating intermediate II-a, whose chemical structural formula is as follows:

[0046] ;

[0047] The photoinitiator can be selected from one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone; in this experimental example, 2,2-dimethoxy-2-phenylacetophenone was selected.

[0048] Process 2: An amino-enyl addition reaction occurs between the -NH2 functional group of 1 molar equivalent intermediate II-a and the α,β-alkenyl functional group of 0.94 molar equivalent 2-hydroxy-4-acryloyloxyethoxybenzophenone (UV absorber UV-2098), generating intermediate II-b, whose chemical structural formula is as follows:

[0049] ;

[0050] Process 3: Based on the Kabachnik-Fields reaction mechanism, a condensation reaction occurs between intermediate II-b, diethyl phosphite, and paraformaldehyde to generate UV-absorbing flame-retardant coupling monomer II, whose chemical structural formula is as follows:

[0051] ;

[0052] The specific experimental steps for preparing UV-absorbing flame-retardant coupling monomer II are as follows:

[0053] Under nitrogen protection, 8.4 g of vinylheptaisobutyl POSS, 0.1 g of 2,2-dimethoxy-2-phenylacetophenone, and 80 mL of anhydrous tetrahydrofuran were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, under UV irradiation (360 nm, 10 cm), 10 mL of 4-aminothiophenol solution (prepared from 1.3 g of 4-aminothiophenol and 10 mL of anhydrous tetrahydrofuran) was added dropwise to the three-necked flask. After the addition was complete, the reaction was stirred under UV irradiation for 60 min. The solvent was removed by rotary evaporation, and the product was washed with anhydrous ethanol and dried to obtain intermediate II-a.

[0054] 4.8 g of intermediate II-a and 50 mL of anhydrous tetrahydrofuran were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 10 mL of 2-hydroxy-4-acryloyloxyethoxybenzophenone solution (prepared from 1.5 g of 2-hydroxy-4-acryloyloxyethoxybenzophenone and 10 mL of anhydrous tetrahydrofuran) was added dropwise to the three-necked flask. The mixture was stirred at room temperature for 30 min, heated to 60 °C and stirred for 10 h. After cooling to room temperature, the solvent was removed by rotary evaporation and dried to obtain intermediate II-b.

[0055] Under nitrogen protection, 4.3 g of intermediate II-b, 0.5 g of diethyl phosphite, 30 mL of anhydrous tetrahydrofuran and 15 mL of anhydrous ethanol were added to a three-necked flask, stirred and mixed at room temperature for 30 min, heated to 70 °C and stirred for 5 h, cooled to room temperature, the solvent was removed by rotary evaporation, washed with anhydrous ethanol and dried to obtain UV-absorbing flame-retardant coupling monomer II.

[0056] The proton NMR spectrum characterization of UV-absorbing flame-retardant coupling monomer II is as follows: 1H NMR (CDCl3, 400MHz) δ: 0.53-0.65 (m, 14H), 0.82-0.86 (t, 2H), 0.92-0.94 (d, 42H), 1.35-1.39 (t, 6H), 1.68-1.79 (m, 7H), 2.59-2.62 (t, 2H) ), 2.96-3.00(t, 2H), 3.66-3.70(t, 2H), 3.97-4.00(d, 2H), 4.15-4.23(m, 6H), 4.37-4.41(t, 2H), 6.58-7.73(m, 12H). Example 1:

[0057] Preparation of UV-absorbing flame-retardant attapulgite I: The phosphorus hydroxyl functional group obtained by hydrolysis of UV-absorbing flame-retardant coupling monomer I undergoes a dehydration condensation reaction with the hydroxyl functional groups abundant on the surface of hydrophilic attapulgite, thereby modifying the surface of attapulgite with UV-absorbing flame-retardant coupling monomer I to obtain UV-absorbing flame-retardant attapulgite I.

[0058] The specific experimental steps for preparing UV-absorbing flame-retardant attapulgite I are as follows: 5g of hydrophilic attapulgite powder (1000 mesh particle size), 50mL of anhydrous tetrahydrofuran, and 10mL of deionized water are added to a three-necked flask. The mixture is ultrasonically dispersed for 1 hour and stirred at room temperature for 2 hours. Then, 20mL of UV-absorbing flame-retardant coupling monomer I solution (prepared from 3g of UV-absorbing flame-retardant coupling monomer I and 20mL of anhydrous tetrahydrofuran) and 5 drops of concentrated hydrochloric acid are added to the three-necked flask. The mixture is heated to 60℃ and stirred for 4 hours. After cooling to room temperature, the mixture is filtered and separated. The mixture is repeatedly washed and filtered with deionized water and dried to obtain UV-absorbing flame-retardant attapulgite I. Example 2:

[0059] Preparation of UV-absorbing flame-retardant attapulgite II: The phosphorus hydroxyl functional group obtained by the hydrolysis reaction of UV-absorbing flame-retardant coupling monomer II undergoes a dehydration condensation reaction with the hydroxyl functional groups abundant on the surface of hydrophilic attapulgite, thereby modifying the surface of attapulgite with UV-absorbing flame-retardant coupling monomer II to obtain UV-absorbing flame-retardant attapulgite II.

[0060] The specific experimental steps for preparing UV-absorbing flame-retardant attapulgite II are the same as those for preparing UV-absorbing flame-retardant attapulgite I, with the only difference being that UV-absorbing flame-retardant coupling monomer I is replaced by UV-absorbing flame-retardant coupling monomer II. Example 3:

[0061] An attapulgite-reinforced functional coating, the formulation of which is shown in Table 1;

[0062] Table 1 Formulation of Attapulgite-Reinforced Functional Coatings

[0063]

[0064] Among them, the UV-absorbing flame-retardant attapulgite is UV-absorbing flame-retardant attapulgite I or UV-absorbing flame-retardant attapulgite II. Example 4:

[0065] A method for preparing an attapulgite-reinforced functional coating is as follows: According to the formula in Table 1, the formula amounts of water, wetting agent, dispersant, defoamer, and leveling agent are mixed and stirred at 500 r / min for 10 min. Then, the formula amounts of talc powder and barium sulfate are added sequentially, and the speed is increased to 1500 r / min for stirring and dispersing for 10 min. The mixture is then ground and dispersed using a sand mill for 1 h, and cooling water is circulated. After that, the formula amounts of pure acrylic emulsion and styrene-acrylic emulsion are added, and the speed is reduced to 1000 r / min for stirring for 15 min. The formula amount of UV-absorbing flame-retardant attapulgite is added while maintaining the speed of 1000 r / min, and the mixture is stirred and mixed for 20 min. Finally, the formula amount of hydroxyethyl cellulose is added while maintaining the speed of 1000 r / min and stirred for 5 min. The speed is reduced to 300 r / min, and the mixture is defoamed at low speed for 30 min. The mixture is then filtered through 100-mesh gauze and stirred evenly to obtain the attapulgite-reinforced functional coating.

[0066] Among them, when the UV-absorbing flame-retardant attapulgite is UV-absorbing flame-retardant attapulgite I, the prepared coating product is denoted as attapulgite-reinforced functional coating I.

[0067] When the UV-absorbing flame-retardant attapulgite is UV-absorbing flame-retardant attapulgite II, the resulting coating product is denoted as attapulgite-reinforced functional coating II.

[0068] Performance testing:

[0069] I. A Q235 steel plate with dimensions of 150mm × 70mm × 3mm was used as the experimental substrate. First, the steel plate underwent pretreatment: the surface was sanded with 800# silicon carbide sandpaper, and then cleaned sequentially with deionized water, anhydrous ethanol, and then deionized water, followed by drying. Next, the coating product was evenly applied to the pretreated steel plate using a brush, controlling the coating thickness to 2mm. It was then allowed to air dry naturally for 7 days before performance testing. The specific testing methods are as follows:

[0070] (1) Fire resistance test: In accordance with GB 14907-2018 "Fireproof Coating for Steel Structures" standard, the fire resistance of the coating samples was tested by the large plate burning method. The sample was fixed on the iron frame with the coated surface facing down, and an alcohol torch flame was used to burn it (the vertical distance between the nozzle of the alcohol torch and the coated surface of the test sample was 70mm). A K-type thermocouple was attached to the back of the steel plate, and a data acquisition instrument was connected to collect the back temperature in real time. The time it took for the back temperature to reach 500℃ from room temperature was recorded to characterize the fire resistance of the coating.

[0071] (2) Weather resistance test: The test was conducted in accordance with GB / T 1865-2009 "Artificial weathering and artificial radiation exposure of paints and varnishes with filtered xenon arc radiation". The test parameters were set as follows: light source wavelength 340nm, light irradiance 0.51W / m 2 The light exposure temperature was 60℃, the light exposure period was 4h, the condensation temperature was 50℃, and the condensation period was 4h. The aging of the coatings was evaluated according to the GB / T 1766-2008 standard "Rating Method for Aging of Paint and Varnish Coatings". The gloss loss rate and color difference of the samples were recorded to characterize the weather resistance of the coatings.

[0072] The performance test results are shown in Table 2.

[0073] Table 2 Performance test results of attapulgite-reinforced functional coatings

[0074]

[0075] Note: The only difference between the comparative example and the attapulgite-reinforced functional coating I is that hydrophilic attapulgite powder (1000 mesh) is used instead of UV-absorbing flame-retardant attapulgite I.

[0076] The following conclusions can be drawn from the experimental results in Table 2:

[0077] The coating product prepared by the present invention using the ultraviolet-absorbing flame-retardant attapulgite clay developed independently has achieved significant improvements in fire resistance and weather resistance compared with the coating prepared using conventional attapulgite clay powder.

[0078] II. The comprehensive performance of the coating samples was tested according to the test methods specified in GB 14907-2018 "Fireproof Coatings for Steel Structures". The test results are shown in Table 3 below.

[0079] Table 3 Performance Test Results of Attapulgite-Reinforced Functional Coatings (Part 2)

[0080]

[0081] Note: The insulation efficiency in Table 3 is expressed as the test time when the average temperature of the unexposed side of the sample reaches 500℃.

[0082] The following conclusions can be drawn from the experimental results in Table 3:

[0083] The attapulgite-reinforced functional coating prepared by this invention meets all the technical requirements specified in GB 14907-2018 standard, exhibits superior comprehensive performance, and has practical application value.

Claims

1. A process for the preparation of an attapulgite reinforced functional coating, characterized in that, The method comprises the following steps: Step 1: grafting the ultraviolet absorption type flame-retardant coupling monomer on the surface of the attapulgite through phosphorus hydroxyl-hydroxyl condensation reaction to obtain the ultraviolet absorption type flame-retardant attapulgite; The ultraviolet absorption type flame-retardant coupling monomer is the ultraviolet absorption type flame-retardant coupling monomer I or the ultraviolet absorption type flame-retardant coupling monomer II; The chemical structural formula of the ultraviolet absorption type flame-retardant coupling monomer I is as follows: ； The chemical structural formula of the ultraviolet absorption type flame-retardant coupling monomer II is as follows: ； Step 2: uniformly mixing the ultraviolet absorption type flame-retardant attapulgite as a functional modification component with a film-forming resin, a body filler and a composite additive to prepare the attapulgite reinforced functional coating.

2. A process for the preparation of an attapulgite reinforced functional coating as claimed in claim 1, wherein, The preparation method of the ultraviolet absorption type flame-retardant coupling monomer I is as follows: In the presence of a photoinitiator, 1 mol equivalent of the alkenyl functional group of the vinyl pentamethyl disiloxane and 1.01-1.09 mol equivalent of the mercapto functional group of the 4-aminobenzenethiol undergo a click reaction under the action of ultraviolet light to generate the intermediate I-a; 1 mol equivalent of the -NH2 functional group of the intermediate I-a and 0.91-0.99 mol equivalent of the α,β-alkenyl functional group of the 2-hydroxy-4-acryloyloxyethoxybenzophenone undergo an amine-alkene addition reaction to generate the intermediate I-b; Based on the Kabachnik-Fields reaction mechanism, the intermediate I-b, diethyl phosphite and paraformaldehyde undergo a condensation reaction to generate the ultraviolet absorption type flame-retardant coupling monomer I.

3. A process for the preparation of an attapulgite reinforced functional coating as claimed in claim 1, wherein, The preparation method of the ultraviolet absorption type flame-retardant coupling monomer II is as follows: In the presence of a photoinitiator, 1 mol equivalent of the alkenyl functional group of the vinyl heptaisobutyl POSS and 1.01-1.09 mol equivalent of the mercapto functional group of the 4-aminobenzenethiol undergo a click reaction under the action of ultraviolet light to generate the intermediate II-a; 1 mol equivalent of the -NH2 functional group of the intermediate II-a and 0.91-0.99 mol equivalent of the α,β-alkenyl functional group of the 2-hydroxy-4-acryloyloxyethoxybenzophenone undergo an amine-alkene addition reaction to generate the intermediate II-b; Based on the Kabachnik-Fields reaction mechanism, the intermediate II-b, diethyl phosphite and paraformaldehyde undergo a condensation reaction to generate the ultraviolet absorption type flame-retardant coupling monomer II.

4. A process for the preparation of an attapulgite reinforced functional coating according to claim 2 or 3, characterized in that, The photoinitiator is one of 2,2-dimethoxy-2-phenylphenylacetone, 2-hydroxy-2-methyl-1-phenylpropanone and 2,2-diethoxyphenylacetophenone.

5. A process for the preparation of an attapulgite reinforced functional coating as claimed in claim 1, wherein, The mass ratio of the ultraviolet absorption type flame-retardant coupling monomer to the attapulgite in the ultraviolet absorption type flame-retardant attapulgite is 1:(0.5-2).

6. An attapulgite reinforced functional coating prepared according to the process of any one of claims 1 to 3, characterized in that, The formula of the attapulgite reinforced functional coating is as follows: 15-25 parts by weight of water, 40-50 parts by weight of a film-forming resin, 15-20 parts by weight of a body filler, 10-15 parts by weight of the ultraviolet absorption type flame-retardant attapulgite and 5-10 parts by weight of a composite additive.

7. The attapulgite reinforced functional coating according to claim 6, characterized in that, The film-forming resin is one of a pure acrylic emulsion, a styrene-acrylic emulsion or a combination of both.

8. The attapulgite reinforced functional coating according to claim 6, characterized in that, The body filler is one of talcum powder, barium sulfate and calcium carbonate or a combination of two.

9. The attapulgite reinforced functional coating according to claim 6, characterized in that, The composite additive comprises a wetting agent, a dispersant, a defoaming agent, a leveling agent and a thickening agent.

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