A formaldehyde-removing latex paint composition and a preparation method thereof

Abstract

The present application provides a kind of formaldehyde removal latex paint composition and preparation method thereof, formaldehyde removal latex paint composition includes modified latex as matrix, nano silver ion, silane coupling agent hydrophobic modified nanosilica filler;The weight ratio of silane coupling agent hydrophobic modified nanosilica filler and modified latex is (2-8):100;The modified latex includes polymer with chemical structure as shown in formula (I).The formaldehyde removal latex paint composition of the present application not only improves mechanical properties, but also has the ability to adsorb and remove formaldehyde, cooperates with imino disuccinic acid group chelated silver ion to degrade formaldehyde, realizes the ability of formaldehyde removal latex paint composition to remove formaldehyde persistently.

Description

Technical Field

[0001] This invention relates to the field of interior decoration materials, specifically to a formaldehyde-removing latex paint composition and its preparation method. Background Technology

[0002] Latex paint has been widely used in recent years due to its advantages such as rapid film formation, short construction period, low construction cost, excellent breathability, and washability, making it a popular choice for environmentally friendly coatings in residential construction. However, the addition of many additives to latex paint makes it less environmentally friendly and detrimental to mechanical properties. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a formaldehyde-removing latex paint composition and its preparation method.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a formaldehyde-removing latex paint composition, wherein the formaldehyde-removing latex paint composition comprises modified latex as a matrix, nano silver ions, and silane coupling agent hydrophobically modified nano silica filler; the weight ratio of silane coupling agent hydrophobically modified nano silica filler to modified latex is (2~8):100.

[0005] The modified latex comprises a polymer with a chemical structure as shown in formula (I);

[0006] (I);

[0007] Where n is the number of moles of β-(1,4)-2-amino-2-deoxy-D-glucose monomer in chitosan hydrochloride, and m represents the total number of moles of the two monomers after copolymerization of butyl acrylate and styrene.

[0008] The aforementioned formaldehyde-removing latex paint composition uses modified latex as the matrix and silane coupling agent-modified hydrophobic nano-silica as the filler. The modified latex is copolymerized from butyl acrylate emulsion and styrene emulsion, and modified with iminodisuccinic acid and chitosan. Iminodisuccinic acid and chitosan improve the mechanical properties of acrylic latex and enable the latex to adsorb and remove formaldehyde. The modified latex and silane coupling agent-modified hydrophobic nano-silica have better compatibility, which is beneficial to improving the mechanical properties and formaldehyde adsorption and removal capabilities of the formaldehyde-removing latex paint composition. Iminodisuccinic acid is linked to the main chain of the modified latex polymer via the amino groups on chitosan. The formaldehyde-removing latex paint composition also contains nano-silver ions. After dispersion, the nano-silver ions can chelate with the iminodisuccinic acid groups on the modified latex polymer and are evenly distributed on the modified latex, which can promote the degradation of formaldehyde. The hydrophobic modified nano-silica of the silane coupling agent is used as a filler to cooperate with the modified latex. The modification of the latex by iminodisuccinic acid and chitosan not only improves the mechanical properties, but also has the ability to adsorb and remove formaldehyde. The silver ions chelated with the iminodisuccinic acid groups degrade formaldehyde, thus realizing the long-lasting formaldehyde removal ability of the formaldehyde-removing latex paint composition.

[0009] The preferred formaldehyde-removing latex paint composition, the preparation method of the modified latex includes the following steps;

[0010] (1) Disperse chitosan hydrochloride in 20%~30% concentrated hydrochloric acid, slowly add acrylic acid, heat to 80~95℃, stir and reflux for 2~6 hours;

[0011] (2) After cooling, the product is collected using an ultrafiltration membrane with a pressure of 1500~4000 Da; the chemical structure of the product is shown in Formula II.

[0012] (II);

[0013] (3) The product obtained in step (2) as shown in Formula II is reacted with iminodisuccinic acid to undergo a Bloch reaction of amino and carboxyl groups to obtain a product with a chemical structure as shown in Formula III.

[0014] (III);

[0015] (4) The product obtained in step (3) is copolymerized with butyl acrylate and styrene to obtain a modified latex containing a polymer with the chemical structure shown in formula (I).

[0016] The above preparation method uses chitosan hydrochloride as a raw material. Hydrochloric acid binds to the amino groups on the chitosan hydrochloride, thus protecting the amino groups. When reacting with the carboxyl groups of acrylic acid, the amino groups on chitosan are prevented from participating in the reaction. Furthermore, the carboxyl groups of acrylic acid more readily react with the hydroxyethyl groups on the β-(1,4)-2-amino-2-deoxy-D-glucose monomer in chitosan hydrochloride to obtain the product with the chemical structure shown in Formula II. Then, under alkaline conditions, chitosan hydrochloride is converted into a free amino form, which undergoes a Bloch reaction with iminodisuccinic acid. The amino groups on chitosan react with the carboxyl groups on iminodisuccinic acid. Due to the steric hindrance and electrophilic properties of the carboxyl groups at different positions, the product shown in Formula III is more easily generated, with fewer byproducts. In the final modified latex, unreacted acrylic acid and iminodisuccinic acid are removed by molecular ultrafiltration, resulting in isomers of the product shown in Formula III, which are different due to the different reaction positions of the hydroxyl and carboxyl groups.

[0017] Preferably, the reaction product of step (4) is ultrasonically reacted with the nano silver ion solution to remove the supernatant, and the nano silver ions are chelated with the iminodisuccinic acid group in the polymer as shown in formula (I). The weight ratio of nano silver ions to the reaction product of step (4) is 0.2~0.8:100.

[0018] Preferably, in step (1), the mass ratio of acrylic acid to chitosan hydrochloride is 0.5~2:100; in step (3), the mass ratio of iminodisuccinic acid to chitosan hydrochloride in step (1) is 0.8~2.5:100; the method of reacting the product obtained in step (2) as shown in Formula II with iminodisuccinic acid to obtain the product with the chemical structure shown in Formula III by the Bloch reaction of amino and carboxyl groups includes the following steps:

[0019] After adjusting the pH of the product solution as shown in Formula II to 8-9 with sodium hydroxide, iminodisuccinic acid was added and reacted for 30-60 minutes using Pd2(dba)3 or Pd(OAc)2 as a catalyst; the solvent for the product solution as shown in Formula II was toluene, xylene or 1,4-dioxane.

[0020] Preferably, in step (4), the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is (20~40):(100~150):(100~150).

[0021] More preferably, in step (4), the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is (25~35):(100~150):(100~150).

[0022] More preferably, in step (4), the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is (25~35):(100~150):(100~150), and the weight ratio of butyl acrylate to styrene is (1~1.5):1.

[0023] Preferably, the copolymerization reaction in step (4) is as follows: 0.8 to 1.2 parts by weight of polyoxyethylene octylphenol ether-10 and 1.8 to 2.5 parts by weight of sodium dodecyl sulfonate are dispersed in deionized water to obtain an emulsifier aqueous solution A, wherein the mass fraction of sodium dodecyl sulfonate in the emulsifier aqueous solution is 1% to 1.5%; the product obtained in step (3) is dispersed with butyl acrylate and styrene in the emulsifier aqueous solution A by ultrasonic dispersion to obtain a pre-emulsion B; 25% to 35% of the volume of the pre-emulsion B is added to the initiator at 78 to 85°C under a nitrogen atmosphere and kept at the temperature for 25 to 40 minutes; then the remaining pre-emulsion B and the initiator are slowly added dropwise to the reaction system over 45 to 75 minutes, and the reaction continues for 2.5 to 3.5 hours.

[0024] This invention also provides a method for preparing any of the above-described formaldehyde-removing latex paint compositions, the method comprising the following steps:

[0025] (a) Preparation of modified latex;

[0026] The preparation method of modified latex includes the following steps;

[0027] (1) Disperse chitosan hydrochloride in 20%~30% concentrated hydrochloric acid, slowly add acrylic acid, heat to 80~95℃, stir and reflux for 2~6 hours;

[0028] (2) After cooling, the product is collected using an ultrafiltration membrane with a pressure of 1500~4000 Da; the chemical structure of the product is shown in Formula II.

[0029] (II);

[0030] (3) The product obtained in step (2) as shown in Formula II is reacted with iminodisuccinic acid to undergo a Bloch reaction of amino and carboxyl groups to obtain a product with a chemical structure as shown in Formula III.

[0031] (III);

[0032] (4) The product obtained in step (3) is copolymerized with butyl acrylate and styrene to obtain a modified latex containing a polymer with the chemical structure shown in formula (I).

[0033] (b) The reaction product of step (4) is ultrasonically reacted with the nano silver ion solution to remove the supernatant. The nano silver ions are chelated with the iminodisuccinic acid group in the polymer as shown in formula (I). The weight ratio of nano silver ions to the reaction product of step (4) is 0.2~0.8:100.

[0034] (c) Stir and mix the product from step (b) with the hydrophobically modified nano-silica of silane coupling agent to remove air bubbles.

[0035] Preferably, in step (1), the mass ratio of acrylic acid to chitosan hydrochloride is 0.5~2:100; and in step (3), the mass ratio of iminodisuccinic acid to chitosan hydrochloride in step (1) is 0.8~2.5:100.

[0036] Preferably, in step (4), the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is (20~40):(100~150):(100~150).

[0037] Preferably, the method for reacting the product obtained in step (2) as shown in Formula II with iminodisuccinic acid via a Bloch reaction of the amino and carboxyl groups to obtain the product with the chemical structure shown in Formula III includes the following steps:

[0038] After adjusting the pH of the product solution as shown in Formula II to 8-9 with sodium hydroxide, iminodisuccinic acid was added and reacted for 30-60 minutes using Pd2(dba)3 or Pd(OAc)2 as a catalyst; the solvent for the product solution as shown in Formula II was toluene, xylene or 1,4-dioxane.

[0039] Preferably, the copolymerization reaction in step (4) is as follows: 0.8 to 1.2 parts by weight of polyoxyethylene octylphenol ether-10 and 1.8 to 2.5 parts by weight of sodium dodecyl sulfonate are dispersed in deionized water to obtain an emulsifier aqueous solution A, wherein the mass fraction of sodium dodecyl sulfonate in the emulsifier aqueous solution is 1% to 1.5%; the product obtained in step (3) is dispersed with butyl acrylate and styrene in the emulsifier aqueous solution A by ultrasonic dispersion to obtain a pre-emulsion B; 25% to 35% of the volume of the pre-emulsion B is added to the initiator at 78 to 85°C under a nitrogen atmosphere and kept at the temperature for 25 to 40 minutes; then the remaining pre-emulsion B and the initiator are slowly added dropwise to the reaction system over 45 to 75 minutes, and the reaction continues for 2.5 to 3.5 hours.

[0040] Preferably, the preparation method of silane coupling agent hydrophobically modified nano-silica includes the following steps:

[0041] (I) Disperse γ-glycidoxypropyltrimethoxysilane in an aqueous ethanol solution to obtain mixed solution A, and adjust the pH of mixed solution A to 3.3~3.7;

[0042] (II) Add nano-silica to mixed solution A with pH 3.3~3.7 and stir ultrasonically for 1.5~2.5 hours; the mass ratio of γ-glycidoxypropyltrimethoxysilane to nano-silica is 0.8~2:10;

[0043] (III) Heat the mixture obtained in step (II) to 75~90℃, stir for 18~28 hours, cool and separate the solid particles, wash with water and ethanol to obtain silane-modified nano-silica.

[0044] The beneficial effects of this invention are as follows: This invention provides a formaldehyde-removing latex paint composition and its preparation method. The formaldehyde-removing latex paint composition of this invention uses modified latex as the matrix and silane coupling agent-modified hydrophobic nano-silica as the filler. The modified latex is copolymerized from butyl acrylate emulsion and styrene emulsion, and modified with iminodisuccinic acid and chitosan. Iminodisuccinic acid and chitosan improve the mechanical properties of acrylic latex and enable the latex to adsorb and remove formaldehyde. The modified latex and silane coupling agent-modified hydrophobic nano-silica have better compatibility, which is beneficial to improving the mechanical properties and formaldehyde adsorption and removal ability of the formaldehyde-removing latex paint composition. Iminodisuccinic acid is linked to the main chain of the modified latex polymer via the amino groups on chitosan. The formaldehyde-removing latex paint composition also contains nano-silver ions. After dispersion, the nano-silver ions can chelate with the iminodisuccinic acid groups on the modified latex polymer and are evenly distributed on the modified latex, which can promote the degradation of formaldehyde. The hydrophobic modified nano-silica of the silane coupling agent is used as a filler to cooperate with the modified latex. The modification of the latex by iminodisuccinic acid and chitosan not only improves the mechanical properties, but also has the ability to adsorb and remove formaldehyde. The silver ions chelated with the iminodisuccinic acid groups degrade formaldehyde, thus realizing the long-lasting formaldehyde removal ability of the formaldehyde-removing latex paint composition. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the chemical structure of the polymer of modified latex formula (Ⅰ) in the formaldehyde-removing latex paint composition of the present invention.

[0046] Figure 2 This is a schematic diagram of the preparation process of the modified latex in the formaldehyde-removing latex paint composition of the present invention.

[0047] Figure 3 This is an infrared characterization diagram of the polymer of modified latex formula (Ⅰ) in the formaldehyde-removing latex paint composition of the present invention. Detailed Implementation

[0048] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Example 1

[0049] As an embodiment of the present invention, a formaldehyde-removing latex paint composition includes modified latex as a matrix, nano silver ions, and silane coupling agent hydrophobically modified nano silica filler; the weight ratio of silane coupling agent hydrophobically modified nano silica filler to modified latex is (2~8):100.

[0050] The modified latex comprises a polymer with a chemical structure as shown in formula (I);

[0051] (I);

[0052] Where n is the number of moles of β-(1,4)-2-amino-2-deoxy-D-glucose monomer in chitosan hydrochloride, and m represents the total number of moles of the two monomers after copolymerization of butyl acrylate and styrene.

[0053] The preparation method of the formaldehyde-removing latex paint composition in this embodiment includes the following steps:

[0054] (a) Preparation of modified latex; The method for preparing modified latex includes the following steps;

[0055] (1) Chitosan hydrochloride is dispersed in 25% concentrated hydrochloric acid, acrylic acid is slowly added, heated to 85°C, and stirred and refluxed for 3 hours; in step (1), the mass ratio of acrylic acid to chitosan hydrochloride is 1:100.

[0056] (2) After cooling, the unreacted acrylic acid was removed by ultrafiltration with a 2000 Da membrane and the product was collected; the chemical structure of the product is shown in Formula II.

[0057] (II);

[0058] (3) The product obtained in step (2) as shown in Formula II is subjected to a Bloch reaction of amino and carboxyl groups with iminodisuccinic acid. The product shown in Formula II is dissolved in toluene with a mass fraction of 15%. After adjusting the pH to 8.5 with sodium hydroxide, iminodisuccinic acid is added with Pd2(dba)3 as a catalyst and reacted for 45 minutes. Unreacted iminodisuccinic acid is removed by ultrafiltration membrane with a 2000 Da filter to obtain the product with the chemical structure shown in Formula III. The mass ratio of iminodisuccinic acid in step (3) to chitosan hydrochloride in step (1) is 1.5:100.

[0059] (III);

[0060] (4) The product obtained in step (3) is copolymerized with butyl acrylate and styrene. 1 part by weight of polyoxyethylene octylphenol ether-10 (OP-10) and 2 parts by weight of sodium dodecyl sulfonate (SDS) are dispersed in deionized water to obtain an emulsifier aqueous solution A, in which the mass fraction of sodium dodecyl sulfonate is 1.2%. The product obtained in step (3) is dispersed with butyl acrylate and styrene in the emulsifier aqueous solution A and ultrasonically dispersed to obtain a pre-emulsion B. 30% of the volume of pre-emulsion B is heated and stirred in a three-necked flask, and nitrogen is introduced to replace air and maintain nitrogen. In a nitrogen atmosphere, 30% by volume of initiator (ammonium persulfate mass concentration of 8%) was added at 80°C and the reaction was maintained for 30 minutes. Then, the remaining pre-emulsion B and initiator were slowly added dropwise to the reaction system over 60 minutes. The reaction system was kept under stirring and the reaction was continued for 3 hours. The butyl acrylate and styrene were removed by ultrafiltration membrane with a 2000 Da filter to obtain a modified latex containing a polymer with the chemical structure shown in formula (I). In step (4), the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 30:125:125.

[0061] (b) The reaction product of step (4) is ultrasonically reacted with the nano silver ion solution to remove the supernatant. The nano silver ions are chelated with the iminodisuccinic acid group in the polymer as shown in formula (I). The weight ratio of nano silver ions to the reaction product of step (4) is 0.5:100.

[0062] (c) Stir and mix the product from step (b) with the silane coupling agent-modified hydrophobic nano-silica to remove air bubbles; the preparation method of the silane coupling agent-modified hydrophobic nano-silica includes the following steps.

[0063] (I) Disperse γ-glycidoxypropyltrimethoxysilane in an aqueous ethanol solution to obtain mixed solution A, and adjust the pH of mixed solution A to 3.5;

[0064] (II) Add nano silica to mixed solution A with pH 3.5 and sonicate for 2 hours; the mass ratio of γ-glycidoxypropyltrimethoxysilane to nano silica is 1:10.

[0065] (III) The mixture obtained in step (II) is heated to 80°C and stirred for 24 hours. After cooling, the solid particles are separated and washed with water and ethanol to obtain silane-modified nano-silica. Example 2

[0066] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 20:125:125. Example 3

[0067] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 25:125:125. Example 4

[0068] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 35:125:125. Example 5

[0069] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 40:125:125. Example 6

[0070] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 30:100:150. Example 7

[0071] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 30:110:140. Example 8

[0072] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 30:120:130. Example 9

[0073] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 30:130:120. Example 10

[0074] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 30:140:110. Example 11

[0075] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is 30:150:100. Example 12

[0076] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the mass ratio of iminodisuccinic acid in step (3) to chitosan hydrochloride in step (1) is 0.8:100. Example 13

[0077] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the mass ratio of iminodisuccinic acid in step (3) to chitosan hydrochloride in step (1) is 1.2:100. Example 14

[0078] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the mass ratio of iminodisuccinic acid in step (3) to chitosan hydrochloride in step (1) is 1.8:100. Example 15

[0079] As a formaldehyde-removing latex paint composition of this embodiment of the invention, the only difference between this embodiment and Example 1 is that the mass ratio of iminodisuccinic acid in step (3) to chitosan hydrochloride in step (1) is 2:100.

[0080] Comparative Example 1

[0081] As a formaldehyde-removing latex paint composition of Comparative Example 1 of the present invention, the only difference between this comparative example and Example 1 is that in the preparation method, an equal amount of acrylic acid is used to replace the product obtained in step (3) of step (4) of Example 1; that is, it includes the following steps

[0082] (a) Preparation of modified latex; The method for preparing modified latex includes the following steps;

[0083] Acrylic acid was copolymerized with butyl acrylate and styrene. One part by weight of polyoxyethylene octylphenol ether-10 and two parts by weight of sodium dodecyl sulfonate were dispersed in deionized water to obtain an emulsifier aqueous solution A. The mass fraction of sodium dodecyl sulfonate in the emulsifier aqueous solution was 1.2%. Acrylic acid, butyl acrylate and styrene were dispersed in the emulsifier aqueous solution A by ultrasonic dispersion to obtain a pre-emulsion B. 30% volume of pre-emulsion B was heated and stirred in a three-necked flask. Nitrogen gas was introduced to replace air to maintain a nitrogen atmosphere. Under the nitrogen atmosphere, 30% volume of initiator (ammonium persulfate mass concentration of 8%) was added at 80°C and the reaction was kept at the temperature for 30 minutes. Then, the remaining pre-emulsion B and initiator were slowly added dropwise to the reaction system over 60 minutes. The reaction system was kept stirred and the reaction was continued for 3 hours. The butyl acrylate and styrene were removed by ultrafiltration membrane with a 2000 Da filter to obtain the polymer-modified latex. In step (4), the weight ratio of acrylic acid to butyl acrylate and styrene was 30:125:125.

[0084] (b) The reaction product of step (4) is ultrasonically reacted with the nano silver ion solution to remove the supernatant. The nano silver ions are chelated with the iminodisuccinic acid group in the polymer as shown in formula (I). The weight ratio of nano silver ions to the reaction product of step (4) is 0.5:100.

[0085] (c) Stir and mix the product from step (b) with the silane coupling agent-modified hydrophobic nano-silica to remove air bubbles; the preparation method of the silane coupling agent-modified hydrophobic nano-silica includes the following steps.

[0086] (I) Disperse γ-glycidoxypropyltrimethoxysilane in an aqueous ethanol solution to obtain mixed solution A, and adjust the pH of mixed solution A to 3.5;

[0087] (II) Add nano silica to mixed solution A with pH 3.5 and sonicate for 2 hours; the mass ratio of γ-glycidoxypropyltrimethoxysilane to nano silica is 1:10.

[0088] (III) The mixture obtained in step (II) is heated to 80°C and stirred for 24 hours. After cooling, the solid particles are separated and washed with water and ethanol to obtain silane-modified nano-silica.

[0089] Comparative Example 2

[0090] As a formaldehyde-removing latex paint composition of Comparative Example 1 of the present invention, the only difference between this comparative example and Example 1 is that the preparation method does not include step (3) of Example 1, and the product of formula (II) in step (2) is used to replace the product of formula (III) in step (3) for the copolymerization reaction in step (4).

[0091] The preparation method of this comparative formaldehyde-removing latex paint composition includes the following steps:

[0092] (a) Preparation of modified latex; The method for preparing modified latex includes the following steps;

[0093] (1) Chitosan hydrochloride is dispersed in 25% concentrated hydrochloric acid, acrylic acid is slowly added, heated to 85°C, and stirred and refluxed for 3 hours; in step (1), the mass ratio of acrylic acid to chitosan hydrochloride is 1:100.

[0094] (2) After cooling, the unreacted acrylic acid was removed by ultrafiltration with a 2000 Da membrane and the product was collected; the chemical structure of the product is shown in Formula II.

[0095] (II);

[0096] (3) The product of formula II obtained in step (2) is copolymerized with butyl acrylate and styrene. One part by weight of polyoxyethylene octylphenol ether-10 and two parts by weight of sodium dodecyl sulfonate are dispersed in deionized water to obtain an emulsifier aqueous solution A, where the mass fraction of sodium dodecyl sulfonate in the emulsifier aqueous solution is 1.2%. The product of formula II obtained in step (2) is dispersed with butyl acrylate and styrene in the emulsifier aqueous solution A and ultrasonically dispersed to obtain a pre-emulsion B. 30% of the volume of pre-emulsion B is heated and stirred in a three-necked flask, and nitrogen is introduced to replace air to maintain a nitrogen atmosphere. Under a nitrogen atmosphere, 30% by volume of initiator (ammonium persulfate mass concentration of 8%) was added at 80°C and the reaction was maintained for 30 minutes. Then, the remaining pre-emulsion B and initiator were slowly added dropwise to the reaction system over 60 minutes. The reaction system was kept under stirring and the reaction was continued for 3 hours. The butyl acrylate and styrene that were reacted were removed using a 2000 Da ultrafiltration membrane to obtain a modified latex containing a polymer with the chemical structure shown in formula (I). In step (2), the weight ratio of the product shown in formula II obtained in step (2) to butyl acrylate and styrene is 30:125:125.

[0097] (b) The reaction product of step (3) is ultrasonically reacted with the nano silver ion solution to remove the supernatant. The nano silver ions are chelated with the iminodisuccinic acid group in the polymer as shown in formula (I). The weight ratio of nano silver ions to the reaction product of step (3) is 0.5:100.

[0098] (c) Stir and mix the product from step (b) with the silane coupling agent-modified hydrophobic nano-silica to remove air bubbles; the preparation method of the silane coupling agent-modified hydrophobic nano-silica includes the following steps.

[0099] (I) Disperse γ-glycidoxypropyltrimethoxysilane in an aqueous ethanol solution to obtain mixed solution A, and adjust the pH of mixed solution A to 3.5;

[0100] (II) Add nano silica to mixed solution A with pH 3.5 and sonicate for 2 hours; the mass ratio of γ-glycidoxypropyltrimethoxysilane to nano silica is 1:10.

[0101] (III) The mixture obtained in step (II) is heated to 80°C and stirred for 24 hours. After cooling, the solid particles are separated and washed with water and ethanol to obtain silane-modified nano-silica.

[0102] Comparative Example 3

[0103] As a formaldehyde-removing latex paint composition of Comparative Example 1 of the present invention, the only difference between this comparative example and Example 1 is that the formaldehyde-removing latex paint composition does not contain nano silver ions, that is, in the preparation method, step (b) is not included, in which the product of step (a) is stirred and mixed with silane coupling agent hydrophobically modified nano silica.

[0104] Comparative Example 4

[0105] As a formaldehyde-removing latex paint composition of Comparative Example 1 of the present invention, the only difference between this comparative example and Example 1 is that nano-silica is used to replace the hydrophobically modified nano-silica with silane coupling agent.

[0106] Experimental methods

[0107] (I) Infrared characterization of materials

[0108] The modified latex of Example 1, i.e., the product prepared in step (4) of Example 1, was characterized by infrared spectroscopy. The modified latex of Example 1, i.e., the product prepared in step (4) of Example 1, was mixed with potassium bromide at a weight ratio of 0.5:100 and then compressed into tablets as the sample to be tested.

[0109] The modified latex of Comparative Example 2, i.e. the product prepared in step (3) of Comparative Example 2, was mixed with potassium bromide at a weight ratio of 0.5:100 and then compressed into tablets as a reference sample.

[0110] Infrared test image as follows Figure 3 As shown, by Figure 3 It can be seen that, compared with Comparative Example 2, the 1510~1560cm values ​​of the embodiment are different. -1 There is an absorption peak at 1600~1700 cm⁻¹ -1 There are two absorption peaks, one at 1620 cm⁻¹. -1 1670cm -1 Around 3300cm -1The presence of absorption peaks indicates that the Bloch reaction has occurred and that the product contains peptide bonds. Combined with the absorption peaks of other carbonyl and carboxyl groups, it can be concluded that the product shown in Formula II undergoes a Bloch reaction with iminodisuccinic acid, and the iminodisuccinic acid group is attached to the polymer in the final product modified latex with the chemical structure shown in Formula (I).

[0111] (ii) Thermogravimetric Analysis (TG)

[0112] The sample was dried to prepare a latex film sample. 5 mg of the sample was accurately weighed and tested using a thermogravimetric analyzer (TGA / SDTA851e). The heating range was 30–380 °C, the heating rate was 15 °C / min, and the atmosphere was nitrogen. The weight residue percentage (%) after heating was recorded. Each sample was measured three times, and the average value was taken.

[0113] (III) Impact Strength

[0114] The impact strength of the cantilever beam was tested using an XJUD-5.5 cantilever beam impact testing machine. The specimen dimensions were 80mm × 10mm × 4mm, with a notch of 2mm.

[0115] (iv) Formaldehyde removal capability test

[0116] Samples to be tested: Examples 1-15, Comparative Examples 1-4.

[0117] 1. Experimental Method: Nineteen 2000mL Erlenmeyer flasks were used, and their actual volumes were measured and accumulated as V0. 10mL of deionized water was added to each flask beforehand. A 20mm × 20mm × 4mm sample was suspended inside the flask. The mouth of the flask was then sealed with an airtight membrane, and the joint was sealed with Vaseline. 500μL of 35% formalin solution was added to 10mL of deionized water using a microsyringe, and the needle hole was quickly sealed with an airtight membrane and Vaseline. The flasks were placed in a water bath at 35℃, and the formaldehyde concentration was measured after 48 hours.

[0118] 2. Formaldehyde Concentration Detection Methods

[0119] (1) Sampling: Fill a 15mL gas phase injection bottle with distilled water, use a 10mL syringe to draw gas from the conical flask through the airtight membrane, and use the principle of gas collection by shooting to transfer the gas from the conical flask to the gas phase injection bottle.

[0120] (2) Instruments: Agilent 7890GC gas chromatograph with FID detector.

[0121] (3) Column: BR-5 ms, 15 m × 0. 25 mm, 0. 25 μm; Injector: 200 ℃; Column temperature: 150 ℃; Splitless; Detector: FID.

[0122] (4) Gas injection method: gas chromatograph for detection; external standard method for quantification using a gradient formaldehyde aqueous solution standard curve. The formaldehyde concentration c in the conical flask after 48 hours was obtained. 0。

[0123] Calculate the formaldehyde removal rate (%) of the formaldehyde-removing latex paint composition.

[0124] Removal rate (%) = (0.35 g / mL × 500 (μL) - V0 (mL) × c0 (mg / mL)) / 0.35 g / mL × 500 (μL) × 100%

[0125] The experimental results are shown in Table 1.

[0126] Table 1. Mechanical properties and formaldehyde removal capabilities of formaldehyde-removing latex paint compositions

[0127] sample Thermogravimetric residual rate (%) <![CDATA[Impact strength (KJ / m 2 )]]> Formaldehyde removal rate (%) Example 1 97.55 8.64 95.92 Example 2 98.68 7.76 86.53 Example 3 98.64 8.37 93.66 Example 4 97.55 8.49 94.96 Example 5 97.63 8.41 93.34 Example 6 98.07 8.18 90.46 Example 7 97.57 8.32 92.88 Example 8 98.09 8.54 94.75 Example 9 97.67 8.76 96.57 Example 10 98.24 8.83 97.31 Example 11 98.15 8.67 96.70 Example 12 98.28 8.26 91.10 Example 13 98.15 8.54 94.39 Example 14 98.05 8.61 94.80 Example 15 97.61 8.47 93.38 Comparative Example 1 97.93 7.76 32.16 Comparative Example 2 97.80 7.93 53.87 Comparative Example 3 98.19 6.97 80.38 Comparative Example 4 98.44 8.64 72.47

[0128] As shown in Table 1, iminodisuccinic acid is linked to the main chain of the modified latex polymer via the amino groups on chitosan. The formaldehyde-removing latex paint composition also contains nano-silver ions. After dispersion, the nano-silver ions can chelate with the iminodisuccinic acid groups on the modified latex polymer and are uniformly distributed on the modified latex, which can promote the degradation of formaldehyde. The hydrophobic modified nano-silica of the silane coupling agent is used as a filler to cooperate with the modified latex. The modification of the latex by iminodisuccinic acid and chitosan not only improves the mechanical properties, but also has the ability to adsorb and remove formaldehyde. The silver ions chelated with the iminodisuccinic acid groups degrade formaldehyde, thus realizing the long-lasting formaldehyde removal ability of the formaldehyde-removing latex paint composition.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A formaldehyde-removing latex paint composition, characterized in that, The formaldehyde-removing latex paint composition includes modified latex as a matrix, nano silver ions, and silane coupling agent hydrophobically modified nano silica filler; the weight ratio of silane coupling agent hydrophobically modified nano silica filler to modified latex is (2~8):

100. The modified latex comprises a polymer with a chemical structure as shown in formula (I); （Ⅰ）； Where n is the number of moles of β-(1,4)-2-amino-2-deoxy-D-glucose monomer in chitosan hydrochloride, and m represents the total number of moles of the two monomers after copolymerization of butyl acrylate and styrene.

2. The formaldehyde-removing latex paint composition according to claim 1, characterized in that, The preparation method of modified latex includes the following steps; (1) Disperse chitosan hydrochloride in 20%~30% concentrated hydrochloric acid, slowly add acrylic acid, heat to 80~95℃, stir and reflux for 2~6 hours; (2) After cooling, the product is collected using an ultrafiltration membrane with a pressure of 1500~4000 Da; The chemical structure of the product is shown in Formula II; （Ⅱ）； (3) The product obtained in step (2) as shown in Formula II is reacted with iminodisuccinic acid to undergo a Bloch reaction of amino and carboxyl groups to obtain a product with a chemical structure as shown in Formula III. （Ⅲ）； (4) The product obtained in step (3) is copolymerized with butyl acrylate and styrene to obtain a modified latex containing a polymer with the chemical structure shown in formula (I).

3. The formaldehyde-removing latex paint composition according to claim 2, characterized in that, The reaction product of step (4) is ultrasonically reacted with the nano silver ion solution to remove the supernatant. The nano silver ions are chelated with the iminodisuccinic acid group in the polymer as shown in formula (I). The weight ratio of nano silver ions to the reaction product of step (4) is 0.2~0.8:

100.

4. The formaldehyde-removing latex paint composition according to claim 2, characterized in that, In step (1), the mass ratio of acrylic acid to chitosan hydrochloride is 0.5~2:100; in step (3), the mass ratio of iminodisuccinic acid to chitosan hydrochloride in step (1) is 0.8~2.5:100; the method of reacting the product obtained in step (2) as shown in Formula II with iminodisuccinic acid to obtain the product with the chemical structure shown in Formula III includes the following steps: After adjusting the pH of the product solution as shown in Formula II to 8-9 with sodium hydroxide, iminodisuccinic acid was added and reacted for 30-60 minutes using Pd2(dba)3 or Pd(OAc)2 as a catalyst; the solvent for the product solution as shown in Formula II was toluene, xylene or 1,4-dioxane.

5. The formaldehyde-removing latex paint composition according to claim 2, characterized in that, In step (4), the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is (20~40):(100~150):(100~150). Step (4) copolymerization reaction is as follows: 0.8-1.2 parts by weight of polyoxyethylene octylphenol ether-10 and 1.8-2.5 parts by weight of sodium dodecyl sulfonate are dispersed in deionized water to obtain emulsifier aqueous solution A, in which the mass fraction of sodium dodecyl sulfonate is 1%-1.5%; the product obtained in step (3) is dispersed with butyl acrylate and styrene in emulsifier aqueous solution A and ultrasonically dispersed to obtain preemulsion B; 25%-35% volume of preemulsion B is added to the initiator at 78-85°C under nitrogen atmosphere and kept at the temperature for 25-40 minutes; then the remaining preemulsion B and the initiator are slowly added dropwise to the reaction system over 45-75 minutes, and the reaction continues for 2.5-3.5 hours.

6. The method for preparing the formaldehyde-removing latex paint composition according to any one of claims 1 to 5, characterized in that, The method includes the following steps: (a) Preparation of modified latex; The preparation method of modified latex includes the following steps; (1) Disperse chitosan hydrochloride in 20%~30% concentrated hydrochloric acid, slowly add acrylic acid, heat to 80~95℃, stir and reflux for 2~6 hours; (2) After cooling, the product was collected using an ultrafiltration membrane with a pressure of 1500~4000 Da; the chemical structure of the product is shown in Formula II. （Ⅱ）； (3) The product obtained in step (2) as shown in Formula II is reacted with iminodisuccinic acid to undergo a Bloch reaction of amino and carboxyl groups to obtain a product with a chemical structure as shown in Formula III. （Ⅲ）； (4) The product obtained in step (3) is copolymerized with butyl acrylate and styrene to obtain a modified latex containing a polymer with the chemical structure shown in formula (I). (b) The reaction product of step (4) is ultrasonically reacted with the nano silver ion solution to remove the supernatant. The nano silver ions are chelated with the iminodisuccinic acid group in the polymer as shown in formula (I). The weight ratio of nano silver ions to the reaction product of step (4) is 0.2~0.8:

100. (c) Stir and mix the product from step (b) with the hydrophobically modified nano-silica of silane coupling agent to remove air bubbles.

7. The method for preparing the formaldehyde-removing latex paint composition according to claim 6, characterized in that, In step (1), the mass ratio of acrylic acid to chitosan hydrochloride is 0.5~2:100; in step (3), the mass ratio of iminodisuccinic acid to chitosan hydrochloride in step (1) is 0.8~2.5:

100.

8. The method for preparing the formaldehyde-removing latex paint composition according to claim 6, characterized in that, In step (4), the weight ratio of the product obtained in step (3) to butyl acrylate and styrene is (20~40):(100~150):(100~150); the method of reacting the product obtained in step (2) as shown in formula II with iminodisuccinic acid to obtain the product with the chemical structure shown in formula III by the Bloch reaction of amino and carboxyl groups in step (3) includes the following steps: After adjusting the pH of the product solution as shown in Formula II to 8-9 with sodium hydroxide, iminodisuccinic acid was added and reacted for 30-60 minutes using Pd2(dba)3 or Pd(OAc)2 as a catalyst; the solvent for the product solution as shown in Formula II was toluene, xylene or 1,4-dioxane.

9. The method for preparing the formaldehyde-removing latex paint composition according to claim 6 or 8, characterized in that, Step (4) copolymerization reaction is as follows: 0.8-1.2 parts by weight of polyoxyethylene octylphenol ether-10 and 1.8-2.5 parts by weight of sodium dodecyl sulfonate are dispersed in deionized water to obtain emulsifier aqueous solution A, in which the mass fraction of sodium dodecyl sulfonate is 1%-1.5%; the product obtained in step (3) is dispersed with butyl acrylate and styrene in emulsifier aqueous solution A and ultrasonically dispersed to obtain preemulsion B; 25%-35% volume of preemulsion B is added to the initiator at 78-85°C under nitrogen atmosphere and kept at the temperature for 25-40 minutes; then the remaining preemulsion B and the initiator are slowly added dropwise to the reaction system over 45-75 minutes, and the reaction continues for 2.5-3.5 hours.

10. The method for preparing the formaldehyde-removing latex paint composition according to claim 6, characterized in that, The preparation method of silane coupling agent hydrophobically modified nano-silica includes the following steps: (I) Disperse γ-glycidoxypropyltrimethoxysilane in an aqueous ethanol solution to obtain mixed solution A, and adjust the pH of mixed solution A to 3.3~3.7; (II) Add nano-silica to mixed solution A with pH 3.3~3.7 and stir ultrasonically for 1.5~2.5 hours; the mass ratio of γ-glycidoxypropyltrimethoxysilane to nano-silica is 0.8~2:10; (III) Heat the mixture obtained in step (II) to 75~90℃, stir for 18~28 hours, cool and separate the solid particles, wash with water and ethanol to obtain silane-modified nano-silica.

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