Biphosphate functional monomer containing biphenyl skeleton as well as preparation method and application thereof

Abstract

The invention relates to a diphosphate functional monomer containing a biphenyl skeleton and a preparation method and application thereof, and belongs to the technical field of emulsion polymerization. The phosphate functional monomer disclosed by the invention has the following structural general formulas (I) and (I), in which R1 is H or CH3, R2 is-C (O)-O-or-O, m and n are independently selected from any natural number from 1 to 10, and R is an aromatic or heteroaromatic group with two phenolic hydroxyl groups. The diphosphate functional monomer disclosed by the invention can be used for preparing a metal anti-corrosion emulsion, a coating is formed on a metal substrate through emulsion polymerization, and the adhesive force and the salt spray resistance of the coating can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of emulsion polymerization, and in particular to a rigid skeleton-based bisphosphate functional monomer, a preparation method thereof, and application of the bisphosphate functional monomer in preparing an aqueous emulsion. Background Art

[0002] Emulsion polymerization is an important method for preparing water-based coatings and is widely used in fields such as metal substrate protection. To improve the adhesion of the emulsion to the metal substrate, phosphate functional monomers are often introduced. The phosphate group can form a coordination chelate with the metal ion, thereby improving the adhesion of the coating to the metal substrate.

[0003] At present, monophosphate functional monomers are widely used, but because they only contain one phosphate group and a single chelating site, there is room for improvement in coating performance. The coating formed by applying this type of functional monomer to the emulsion has problems such as weak adhesion and poor corrosion resistance.

[0004] Therefore, there is an urgent need in this field to develop a new type of phosphate functional monomer to improve the adhesion of the coating formed by emulsion polymerization to the metal substrate and the salt spray resistance of the coating. Summary of the Invention

[0005] In response to the above-mentioned problems existing in the prior art, the present invention provides a diphosphate functional monomer that can improve the adhesion and salt spray resistance of the coating.

[0006] In a first aspect of the present invention, a bisphosphate functional monomer is provided, which has the following general structural formula (I): (I) Among them, R 1 is H or CH3, R 2 is -C(O)-O- or -O, m and n are any natural numbers from 1 to 10; R is selected from one of the following groups: wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br.

[0007] In some embodiments of the first aspect of the present invention, m and n in formula (I) are independently selected from any natural number from 1 to 5; preferably, m and n are independently selected from any natural number from 1 to 3; more preferably, m and n are both 1.

[0008] In some embodiments of the first aspect of the present invention, R in formula (I) is selected from one of the following groups: 、 、 、 or .

[0009] In some embodiments of the first aspect of the present invention, the bisphosphate functional monomer of formula (I) has the following structural formula: 、 、 、 or .

[0010] In a second aspect of the present invention, an intermediate compound for preparing the bisphosphate functional monomer of the present invention is provided, which has the following structural formula (II): (II) Among them, R 1 is H or CH3, R 2 is -C(O)-O- or -O, m and n are independently any natural numbers from 1 to 10; R is selected from one of the following groups: wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br.

[0011] In some embodiments of the second aspect of the present invention, m and n in formula (II) are independently selected from any natural number from 1 to 5; preferably, m and n are independently selected from any natural number from 1 to 3; more preferably, m and n are both 1.

[0012] In some embodiments of the second aspect of the present invention, R in formula (II) is selected from one of the following groups: 、 、 、 or .

[0013] In some embodiments of the second aspect of the present invention, the intermediate compound of formula (II) has the following structural formula: 、 、 、 or .

[0014] In a third aspect of the present invention, a method for preparing the bisphosphate functional monomer of the present invention is provided, comprising the following steps: (a) Epoxy ring-opening reaction: An aromatic or heteroaromatic compound having two phenolic hydroxyl groups and an ethylenically unsaturated monomer containing an epoxy group undergo a nucleophilic ring-opening reaction in the presence of a catalyst to form an intermediate compound having the general structural formula (II); Wherein, the aromatic or heteroaromatic compound having two phenolic hydroxyl groups is selected from one of the following compounds: wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; Wherein, the structure of the epoxy-containing ethylenically unsaturated monomer is shown in formula (III): (III) In formula (III), R 1 is H or CH3, R 2 is -C(O)-O- or -O, and m and n are independently any natural numbers from 1 to 10.

[0015] (b) Phosphorylation reaction: The intermediate compound of general formula (II) obtained in step (a) is subjected to a phosphorylation reaction to form a diphosphate functional monomer having a structure such as general formula (I).

[0016] In some embodiments of the third aspect of the present invention, the aromatic or heteroaromatic compound having two phenolic hydroxyl groups has one of the following structural formulas: 、 、 、 、 、 、 、 、 .

[0017] In some embodiments of the third aspect of the present invention, m and n in formula (III) are independently selected from any natural number from 1 to 5; preferably, m and n are independently selected from any natural number from 1 to 3; more preferably, m and n are both 1.

[0018] In some embodiments of the third aspect of the present invention, the epoxy-containing ethylenically unsaturated monomer has one of the following structural formulas: 、 、 、 、 、 、 、 .

[0019] In a fourth aspect of the present invention, there is provided use of the bisphosphate functional monomer according to the first aspect of the present invention in the preparation of a metal anticorrosion emulsion.

[0020] In a fifth aspect of the present invention, a metal anticorrosion emulsion is provided. The emulsion is prepared using the bisphosphate functional monomer according to the first aspect of the present invention.

[0021] In some embodiments of the fifth aspect of the present invention, the metal anticorrosion emulsion is an acrylate emulsion and a copolymer emulsion thereof, a silicone-modified emulsion, or a vinyl emulsion.

[0022] In a sixth aspect of the present invention, a method for forming a coating on a metal substrate is provided, wherein the method uses a coating prepared according to the metal anticorrosion emulsion described in the fifth aspect of the present invention.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a bisphosphate functional monomer with an innovative structure, which has a biphenyl skeleton or a naphthalene ring, anthracene ring or a heterocyclic analog thereof skeleton, a bisphosphate group and a diene bond end-capping structure. Therefore, the bisphosphate functional monomer of the present invention has a rigid skeleton, a double chelating site and high reactivity; when it is used to form a coating on a metal substrate through emulsion polymerization, the coating can significantly improve adhesion and salt spray resistance, and improve mechanical strength.

[0024] (2) The present invention relates to an innovation in the synthesis process of a bisphosphate functional monomer. Specifically, the preparation method of the bisphosphate functional monomer of the present invention is achieved through a two-step reaction of epoxy ring opening-phosphorylation. The process is feasible and further realizes the innovation of the synthesis process of bisphosphate. Specifically, the one-step synthesis of the bisphosphate functional monomer is achieved through a single-step condensation-phosphorylation tandem reaction. Compared with the multi-step reaction path in the prior art that usually requires phenolic hydroxyl protection, phosphorylation and deprotection, the present invention significantly reduces the reaction steps, improves the overall yield, and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the intermediate product 1 prepared according to Example 1 of the present invention ( 1 H NMR).

[0026] Figure 2 is the nuclear magnetic resonance hydrogen spectrum of the product 1 prepared according to Example 1 of the present invention ( 1 H NMR).

[0027] Figure 3 is the nuclear magnetic resonance phosphorus spectrum of the product 1 prepared according to Example 1 of the present invention ( 31 P NMR).

[0028] Figure 4 is the nuclear magnetic resonance hydrogen spectrum of the intermediate product 2 prepared according to Example 2 of the present invention ( 1 H NMR).

[0029] Figure 5 is the nuclear magnetic resonance hydrogen spectrum of the product 2 prepared according to Example 2 of the present invention ( 1 H NMR).

[0030] Figure 6 is the nuclear magnetic resonance phosphorus spectrum of the product 2 prepared according to Example 2 of the present invention ( 31 P NMR).

[0031] Figure 7 is the nuclear magnetic resonance hydrogen spectrum of the intermediate product 3 prepared according to Example 3 of the present invention ( 1 H NMR).

[0032] Figure 8 is the nuclear magnetic resonance hydrogen spectrum of the product 3 prepared according to Example 3 of the present invention ( 1 H NMR).

[0033] Figure 9 is the nuclear magnetic resonance phosphorus spectrum of the product 3 prepared according to Example 3 of the present invention ( 31 P NMR).

[0034] Figure 10 is the nuclear magnetic resonance hydrogen spectrum of the intermediate product 4 prepared according to Example 4 of the present invention ( 1 H NMR).

[0035] Figure 11 is the nuclear magnetic resonance hydrogen spectrum of the product 4 prepared according to Example 4 of the present invention ( 1 H NMR).

[0036] Figure 12 is the nuclear magnetic resonance phosphorus spectrum of the product 4 prepared according to Example 4 of the present invention ( 31 P NMR).

[0037] Figure 13 is the nuclear magnetic resonance hydrogen spectrum of the intermediate product 5 prepared according to Example 5 of the present invention ( 1 H NMR).

[0038] Figure 14 is the nuclear magnetic resonance hydrogen spectrum of the product 5 prepared according to Example 5 of the present invention ( 1 H NMR).

[0039] Figure 15 is the nuclear magnetic resonance phosphorus spectrum of the product 5 prepared according to Example 5 of the present invention ( 31P NMR). DETAILED DESCRIPTION

[0040] Various aspects of the present invention will be described in detail below in conjunction with specific implementation methods. These specific embodiments are only used to illustrate the present invention and do not limit the scope of protection and substantive content of the present invention.

[0041] In the structural design of the bisphosphate functional monomer represented by formula (I) of the present invention, a rigid skeleton containing aromatic or heteroaromatic groups is selected, the two ends are connected to the epoxy groups containing olefinic bonds through an epoxy ring-opening reaction, and the bisphosphate groups are introduced through phosphorylation.

[0042] The rigid skeleton in the diphosphate functional monomer structure of the present invention restricts the spatial orientation of the diphosphate groups, forming a double chelate structure, thereby achieving efficient chelation of the metal substrate.

[0043] The rigid skeleton in the bisphosphate functional monomer structure of the present invention includes a divalent aromatic or heteroaromatic linking group, which can be selected from: 4,4'-biphenyldiphenol group, 3,3'-dimethyl-4,4'-biphenyldiphenol group, 2,2'-difluoro-4,4'-biphenyldiphenol group, 5,8-dihydroxyquinoline group, 2,4-dihydroxyquinoline group, 2,8-dihydroxyquinoline group, 6-fluoro-2,4-dihydroxyquinoline group, 1,5-dihydroxynaphthyl group, 2,3-dihydroxynaphthyl group, 4,7-dihydroxybenzo[d]thienyl group, etc.

[0044] In the bisphosphate functional monomer structure of the present invention, end groups having ethylenically unsaturated groups are introduced at both ends through an epoxy ring-opening reaction. The ethylenically unsaturated groups can be selected from: -CH2-CH(OH)-CH2-OC(O)-CH=CH2 derived from an acryloyloxy group (-CH2=CH-C(O)O-) epoxy ring-opening, -CH2-CH(OH)-CH2-OC(O)-CH=CH2 derived from a methacryloyloxy group (-CH2=C(CH3)-C(O)O-) epoxy ring-opening, -CH2-CH(OH)-CH2-OC(O)-C(CH3)=CH2 derived from a methacryloyloxy group (-CH2=C(CH3)-C(O)O-) epoxy ring-opening, -CH2-CH(OH)-CH2-OC(O)-C(CH3)=CH2 derived from an allyloxy group (-CH2=CH-CH2-O-) epoxy ring-opening, -CH2-CH(OH)-CH2-O-CH2-CH=CH2 derived from a methallyloxy group (-CH2=C(CH3)-CH2-O-) epoxy ring-opening, and the like. The double bond double-end design enables the monomer to participate in emulsion polymerization cross-linking to form a dense network structure, significantly improving the mechanical strength and thermal stability of the material.

[0045] In the structure of the bisphosphate functional monomer of the present invention, the hydroxyl groups provide dual chelating sites, which can enhance the chemical bonding with the metal substrate.

[0046] In the bisphosphate functional monomers of this invention, the rigid backbone stabilizes the spatial configuration of the bisphosphate groups, optimizing the geometric matching (e.g., bond distance / angle) of their chelating sites to accommodate the coordination requirements of the target metal ions. Simultaneously, the cross-linked network formed by the monomers anchors the chelating groups to the polymer matrix and regulates their microenvironment and accessibility. These two factors synergistically enhance the chelation capacity and stability of interfacial metal ions, thereby improving the coating's adhesion, corrosion inhibition, and other protective properties.

[0047] In the bisphosphate functional monomer structure of the present invention, an epoxy-containing ethylenically unsaturated monomer (such as glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether) is selected to further optimize the corrosion resistance or interfacial compatibility of the phosphate group by reacting its epoxy group with the phosphate group.

[0048] The preparation of the bisphosphate functional monomer of the present invention includes an epoxy ring-opening reaction and a phosphorylation reaction. In the epoxy ring-opening reaction, the starting materials are an aromatic or heteroaromatic compound having two phenolic hydroxyl groups and one or two molecules of an ethylenically unsaturated monomer containing an epoxy group. In the presence of a catalyst, the phenolic hydroxyl groups undergo nucleophilic ring-opening of the epoxy groups, producing a diepoxy ring-opening intermediate product with an aromatic or heteroaromatic rigid backbone and end-capped with ethylenically unsaturated groups at both ends. In the phosphorylation reaction, the intermediate product reacts with a phosphorylation reagent to phosphorylate the two hydroxyl (-OH) groups in the molecule, thereby introducing two phosphate groups into the molecule and obtaining the target bisphosphate functional monomer.

[0049] In the preparation of the bisphosphate functional monomer of the present invention, the aromatic or heteroaromatic compound having two phenolic hydroxyl groups as a reaction raw material can be selected from: 4,4'-biphenyldiphenol, 3,3'-dimethyl-4,4'-biphenyldiphenol, 2,2'-difluoro-4,4'-biphenyldiphenol, 5,8-dihydroxyquinoline, 2,4-dihydroxyquinoline, 2,8-dihydroxyquinoline, 6-fluoro-2,4-dihydroxyquinoline, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 4,7-dihydroxybenzo[d]thiophene, etc., or derivatives of the above compounds substituted by 1 to 3 substituents independently selected from halogen or alkyl.

[0050] In the preparation of the bisphosphate functional monomer of the present invention, the epoxy-containing ethylenically unsaturated monomer used as a reaction raw material has an ethylenically unsaturated end group, which can be selected from compounds containing an acryloyloxy group (CH2=CH-C(O)O-), compounds containing a methacryloyloxy group (CH2=C(CH3)-C(O)O-) or compounds containing an allyloxy group (CH2=CH-CH2-O-), such as glycidyl esters containing acryloyloxy or methacryloyloxy or glycidyl ethers containing allyloxy.

[0051] In the preparation method of the bisphosphate functional monomer of the present invention, the catalyst used in the epoxy ring-opening reaction includes one or more of the following catalysts: tertiary amine, quaternary ammonium salt, boron trifluoride or its ether complex salt, aluminum chloride, barium oxide, tin tetrachloride, sodium hydroxide, potassium hydroxide, etc.

[0052] In the method for preparing the bisphosphate functional monomer of the present invention, the phosphorylation reagent used in the phosphorylation reaction includes one or more of the following reagents: phosphorus oxychloride, phosphorus pentoxide, phosphoric acid or polyphosphoric acid (PPA).

[0053] The intermediate compound generated by the epoxy ring-opening reaction is dried and purified by reduced pressure distillation to obtain the obtained product.

[0054] The bisphosphate functional monomer of the present invention can be used as a functional comonomer for the synthesis of aqueous polymer emulsions, such as metal anticorrosion emulsions, and is suitable for the preparation of emulsions containing the following systems, such as acrylates and their copolymer emulsions, silicone-modified emulsions, vinyl emulsions, and inorganic-organic hybrid emulsions.

[0055] The emulsion prepared using the bisphosphate functional monomer of the present invention can be used to form a coating on the surface of a metal substrate, and its application can be extended to the fields of metal surface treatment, anti-corrosion coating, electronic packaging, etc.

[0056] The following is a detailed description of the bisphosphate functional monomer of the present invention and its preparation method and application by way of examples.

[0057] Example 1

[0058] The synthetic route of the bisphosphate functional monomer of the present embodiment is as follows:

[0059] 4,4'-Bisphenol (48 g, 0.26 mol) and 100 mL of 1,4-dioxane were added to a dry 500 mL three-necked reaction flask, and tin tetrachloride (1.2 g) was added as a catalyst under nitrogen protection. The system was heated to 80°C and stirred until the solid was completely dissolved, then glycidyl acrylate (65 g, 0.57 mol) was added and the reaction was continued at 80°C with stirring for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, 2 mL of methanol was added to quench the reaction, and the white precipitate was collected by filtration. The filter cake was washed thoroughly with 3×50 mL of dichloromethane in sequence (filtered after each wash). All the filtrates and washings were combined and distilled under reduced pressure (20 kPa, temperature 50°C) to remove dichloromethane and low-boiling impurities. The obtained residue was dried in a drying oven to obtain the intermediate product 1 as colorless crystals (yield 92%). 1H NMR characterization confirmed that the chemical structure of intermediate 1 was 3,3'-[4,4'-biphenyldioxy]bis[1-allyloxy-2-propanol]. 1 H NMR spectrum Figure 1 shown. 1 H NMR (600 MHz, CDCl3) δ 7.59– 7.53 (m, 4H), 6.88 – 6.81 (m, 4H), 5.91 – 5.79 (m, 2H), 5.22 (dtt, J =11.9, 2.0, 0.9 Hz, 2H), 5.06 (dtt, J = 11.9, 2.0, 1.1 Hz, 2H), 4.21 (p, J =5.6 Hz, 2H), 4.09 (dd, J = 11.4, 5.7 Hz, 2H), 4.00 (dd, J = 11.4, 5.6 Hz, 2H), 3.95 (dt, J = 6.2, 0.9 Hz, 4H), 3.59 (dd, J = 11.4, 5.5 Hz, 2H), 3.46(dd, J = 11.3, 5.5 Hz, 2H).

[0060] The intermediate product 1 (50 g, 0.12 mol) was placed in a dry 500 mL three-necked flask, heated to 80 ° C and kept constant. Phosphorus oxychloride (POCl3, 38 g, 0.25 mol) was slowly added dropwise through a constant pressure dropping funnel, and the addition rate was controlled to be completed within 1 hour. After the addition was completed, stirring and reacting were continued at 80 ° C for 3 hours. The system was then heated to 90 ° C, and deionized water (0.8 g, 0.044 mol) was slowly added through a micro-injection pump under strong stirring. The water addition rate was controlled to avoid local overheating. After the addition was completed, the reaction was refluxed at 90 ° C for 24 hours. After the reaction solution was cooled to room temperature, the product 1 was finally obtained as a yellow-brown crystalline solid (yield 98%). The structure of product 1 is shown in FIG. 1 H NMR and 31 P NMR characterization confirmed that it was 4,4'-biphenyldioxybis[3-allyloxypropane-1,2-diyl]bis(dihydrogen phosphate). The specific characterization results are as follows: 1H NMR (600 MHz, CDCl3) δ 7.59 – 7.53 (m, 4H), 6.88 – 6.81 (m, 4H), 5.91 – 5.79 (m, 2H), 5.22 (dtt, J = 11.9, 2.0, 0.9 Hz, 2H), 5.06 (dtt, J =11.9, 2.0, 1.1 Hz, 2H), 4.21 (p, J = 5.6 Hz, 2H), 4.09 (dd, J = 11.4, 5.7 Hz, 2H), 4.00 (dd, J = 11.4, 5.6 Hz, 2H), 3.95 (dt, J = 6.2, 0.9 Hz, 4H), 3.59(dd, J = 11.4, 5.5 Hz, 2H), 3.46 (dd, J = 11.3, 5.5 Hz, 2H). 1 H NMR spectrum Figure 2 shown.

[0061] 31 P NMR (600 MHz, CDCl3) δ 1.98 (s, 2P). 31 P NMR spectrum is as follows Figure 3 shown.

[0062] Example 2

[0063] The synthetic route of the bisphosphate functional monomer of the present embodiment is as follows:

[0064] 2,2'-difluoro-4,4'-biphenyldiphenol (55.5 g, 0.25 mol) and 100 mL of 1,4-dioxane were added to a dry 500 mL three-necked reaction flask. Sodium hydroxide (1.4 g) was added as a catalyst under nitrogen protection. The system was heated to 120°C and stirred until the solid was completely dissolved. Then, glycidyl methacrylate (81 g, 0.57 mol) was added and the reaction was continued at 120°C with stirring for 3.5 hours. After the reaction was completed, the mixture was cooled to room temperature and quenched with 2 mL of methanol. The white precipitate was collected by filtration. The filter cake was washed thoroughly with 3×50 mL of dichloromethane (filtered after each wash). All the filtrates and washings were combined and distilled under reduced pressure (20 kPa, temperature 50°C) to remove dichloromethane and low-boiling impurities. The obtained residue was dried in a drying oven to obtain intermediate product 2 as colorless crystals (yield 87%). Its structure was described by 1H NMR characterization confirmed that its chemical structure was 4,4'-bis[(2-hydroxypropane-1,3-diyl)oxy]-2,2'-difluorobiphenyl bis(2-methylacrylate). 1 HNMR spectrum Figure 4 shown. 1 H NMR (600 MHz, CDCl3) δ 7.28 – 7.21 (m, 2H), 6.99 (dd, J =8.4, 1.8 Hz, 1H), 6.82 (dd, J = 8.0, 1.9 Hz, 2H), 6.75 (dd, J = 8.4, 2.0 Hz, 1H), 6.31 (ddq, J = 15.0, 2.0, 0.9 Hz, 2H), 5.89 (ddq, J = 15.0, 2.0, 0.9 Hz, 2H), 4.50 – 4.41 (m, 4H), 4.32 – 4.24 (m, 2H), 4.13 (dd, J = 11.5, 5.3 Hz,2H), 4.09 – 4.01 (m, 2H), 1.92 (t, J = 1.0 Hz, 6H).

[0065] The intermediate product 2 (60.8 g, 0.12 mol) was added to a dry 500 mL three-necked reaction vessel in a flask, and the temperature was raised to 75°C and kept constant. Phosphorus pentoxide (P2O5, 35.5 g, 0.25 mol) was added in three portions using a screw feeder. The addition was completed within 1 hour and the reaction was maintained for 3 hours. The system was then heated to 90°C and 0.8 g of deionized water was slowly added for hydrolysis. Stirring was continued for 24 hours. After the reaction solution was cooled to room temperature, product 2 was obtained as a yellow-brown crystalline solid (yield 97%). The structure of product 2 was 1 H NMR and 31 P NMR characterization confirmed that it was 4,4'-bis{[2-(phosphooxy)propane-1,3-diyl]oxy}-2,2'-difluorobiphenyl bis(2-methylacrylate). The specific characterization results are as follows: 1H NMR (600 MHz, CDCl3) δ 7.41 (ddd, J = 8.4, 5.0, 2.0 Hz, 2H), 6.84 (dd, J = 8.0, 1.9 Hz, 2H), 6.76 (dd, J = 8.4, 1.9 Hz, 2H), 6.33 (ddq, J =15.0, 2.0, 0.9 Hz, 2H), 5.90 (ddq, J = 15.0, 2.0, 0.9 Hz, 2H), 5.11 (dp, J =8.1, 5.6 Hz, 2H), 4.64 (dd, J = 11.3, 5.6 Hz, 2H), 4.45 (dd, J = 11.3, 5.6Hz, 2H), 4.29 (dd, J = 11.4, 5.6 Hz, 2H), 4.22 (dd, J = 11.4, 5.6 Hz, 2H),1.94 (t, J = 1.0 Hz, 6H). 1 H NMR spectrum Figure 5 shown.

[0066] 31 P NMR (600 MHz, CDCl3) δ 2.08 (s, 2P). 31 P NMR spectrum is as follows Figure 6 shown.

[0067] Example 3

[0068] The synthetic route of the bisphosphate functional monomer of the present embodiment is as follows:

[0069] 1,5-Dihydroxynaphthalene (45 g, 0.28 mol) and 100 mL of 1,4-dioxane were added to a dry, 500 mL, three-necked reaction flask. Boron trifluoride etherate (BF3•Et2O, 0.9 g) was added as a catalyst under nitrogen. The system was heated to 40°C and stirred until the solid was completely dissolved. Glycidyl methacrylate (81 g, 0.57 mol) was then added and stirred at 400°C for 4 hours. After the reaction, the mixture was cooled to room temperature and quenched with 2 mL of methanol. The white precipitate was collected by filtration. The filter cake was washed thoroughly with 3 × 50 mL of dichloromethane (filtered after each wash). The filtrate and washings were combined and distilled under reduced pressure (20 kPa, 50°C) to remove dichloromethane and low-boiling impurities. The resulting residue was dried in a drying oven to obtain intermediate 3 as colorless crystals (85% yield). Its chemical structure was confirmed by the following equation: 1H NMR characterization confirmed that it was (1,5-naphthalenedioxy)bis(3-hydroxy-1,3-propanediyl)bis(2-methacrylate). 1 H NMR spectrum Figure 7 shown. 1 H NMR (600MHz, CDCl3) δ 7.88 (dt, J = 7.8, 0.7 Hz, 2H), 7.38 (t, J = 7.8 Hz, 2H), 7.09– 7.03 (m, 2H), 6.31 (ddq, J = 2.0, 0.9, 0.2 Hz, 2H), 5.89 (ddq, J = 15.0,2.0, 0.9 Hz, 2H), 4.49 – 4.42 (m, 4H), 4.32 – 4.25 (m, 2H), 4.19 – 4.12 (m,2H), 4.15 – 4.04 (m, 2H), 1.92 (t, J = 1.0 Hz, 6H).

[0070] The intermediate product 3 (53.3 g, 0.12 mol) was added to a dry 500 mL three-necked reaction vessel. The system temperature was controlled at 85°C, and phosphoric acid (H3PO4, 35.5 g, 0.25 mol) was slowly added dropwise. The addition was completed within 1 hour, and the reaction was maintained for 3 hours. The system was then heated to 85°C, and 0.8 g of deionized water was slowly added for hydrolysis. Stirring was continued for 24 hours. After the reaction solution was cooled to room temperature, product 3 was obtained as a yellow-brown crystalline solid (yield 96%). The structure of product 3 was determined by 1 H NMR and 31 P NMR characterization confirmed that it was 1,5-bis[3-(2-methacryloyloxy)-2-phosphooxypropoxy]naphthalene. The specific characterization results are as follows: 1H NMR (600 MHz, CDCl3) δ 7.80 (dt, J = 7.9, 0.7 Hz, 2H), 7.47 (t, J =7.9 Hz, 1H), 7.38 (t, J = 7.9 Hz, 1H), 7.09 – 7.03 (m, 2H), 6.31 (ddq, J =15.0, 2.0, 0.9 Hz, 2H), 5.89 (ddq, J = 15.0, 2.0, 0.9 Hz, 2H), 5.10 (dp, J =8.2, 5.6 Hz, 2H), 4.61 (dd, J = 11.3, 5.6 Hz, 2H), 4.43 (dd, J = 11.3, 5.6Hz, 2H), 4.30 (dd, J = 11.4, 5.6 Hz, 2H), 4.23 (dd, J = 11.4, 5.6 Hz, 2H),1.92 (t, J = 1.0 Hz, 6H). 1 H NMR spectrum Figure 8 shown.

[0071] 31 P NMR (600 MHz, CDCl3) δ 2.23 (s, 2P). 31 P NMR spectrum is as follows Figure 9 shown.

[0072] Example 4

[0073] The synthetic route of the bisphosphate functional monomer of the present embodiment is as follows:

[0074] 4,7-Dihydroxybenzo[d]thiophene (46.5 g, 0.28 mol) and 100 mL of 1,4-dioxane were added to a dry, 500 mL, three-necked reaction flask. Boron trifluoride etherate (BF3•Et2O, 0.9 g) was added as a catalyst under nitrogen. The system was heated to 40°C and stirred until the solid was completely dissolved. Glycidyl methacrylate (81 g, 0.57 mol) was added and the reaction continued at 400°C with stirring for 4 hours. After the reaction, the mixture was cooled to room temperature and quenched with 2 mL of methanol. The white precipitate was collected by filtration. The filter cake was washed thoroughly with 3 × 50 mL of dichloromethane (filtered after each wash). The filtrate and washings were combined and distilled under reduced pressure (20 kPa, 50°C) to remove dichloromethane and low-boiling impurities. The resulting residue was dried in a drying oven to obtain intermediate 4 as colorless crystals (87% yield). Its chemical structure was confirmed by the following equation:1 H NMR characterization confirmed that it was 4,7-bis(2-methacryloyloxy-3-hydroxypropyloxy)benzo[b]thiophene. 1 H NMR spectrum Figure 10 shown. 1 HNMR (600 MHz, CDCl3) δ 7.47 (d, J = 6.1 Hz, 1H), 7.37 (d, J = 6.0 Hz, 1H), 6.88 (d, J = 8.4 Hz, 1H), 6.80 (d, J = 8.5 Hz, 1H), 6.31 (ddq, J = 15.4, 2.0,0.9 Hz, 2H), 5.89 (ddq, J = 14.6, 2.0, 0.9 Hz, 2H), 4.51 – 4.42 (m, 4H), 4.32– 4.25 (m, 2H), 4.20 – 4.11 (m, 2H), 4.14 – 4.04 (m, 2H), 1.92 (t, J = 1.0 Hz, 8H).

[0075] The intermediate product 4 (54.1 g, 0.12 mol) was added to a dry 500 mL three-necked reaction vessel. The system temperature was controlled at 85°C, and phosphoric acid (H3PO4, 35.5 g, 0.25 mol) was slowly added dropwise. The addition was completed within 1 hour, and the reaction was maintained for 3 hours. The system was then heated to 85°C, and 0.8 g of deionized water was slowly added for hydrolysis. Stirring was continued for 24 hours. After the reaction solution was cooled to room temperature, product 4 was obtained as a brown crystalline solid (yield 95%). The structure of product 4 was determined by 1 H NMR and 31 P NMR characterization confirmed that it was bis(methacryloyloxy)-3-phosphoglycerol ether benzothiophene. The specific characterization results are as follows: 1H NMR (600 MHz, CDCl3) δ 7.46 (d, J = 6.2 Hz, 1H), 7.30 (d, J = 6.2Hz, 1H), 6.91 – 6.83 (m, 2H), 6.31 (ddq, J = 15.4, 2.0, 0.9 Hz, 2H), 5.89(ddq, J = 14.6, 2.0, 0.9 Hz, 2H), 5.15 – 5.04 (m, 2H), 4.61 (dd, J = 11.2,5.5 Hz, 2H), 4.43 (dd, J = 11.3, 5.6 Hz, 2H), 4.30 (dd, J = 11.4, 5.6 Hz,2H), 4.23 (dd, J = 11.4, 5.5 Hz, 2H), 1.92 (t, J = 1.0 Hz, 6H). 1 H NMR spectrum Figure 11 shown.

[0076] 31 P NMR (600 MHz, CDCl3) δ 1.97 (s, 2P). 31 P NMR spectrum is as follows Figure 12 shown.

[0077] Example 5

[0078] The synthetic route of the bisphosphate functional monomer of the present embodiment is as follows:

[0079] 5,8-Dihydroxyquinoline (45 g, 0.28 mol) and 100 mL of 1,4-dioxane were added to a dry 500 mL three-necked reaction flask. Boron trifluoride etherate (BF3•Et2O, 0.9 g) was added as a catalyst under nitrogen protection. The system was heated to 40°C and stirred until the solid was completely dissolved. Glycidyl methacrylate (81 g, 0.57 mol) was added and the reaction was continued at 400°C with stirring for 4 hours. After the reaction, the mixture was cooled to room temperature and quenched by the addition of 2 mL of methanol. The white precipitate was collected by filtration. The filter cake was washed thoroughly with 3 × 50 mL of dichloromethane (filtered after each wash). All filtrates and washings were combined and distilled under reduced pressure (20 kPa, temperature 50°C) to remove dichloromethane and low-boiling impurities. The resulting residue was dried in a drying oven to obtain intermediate 5 as colorless crystals (yield 82%). 1 H NMR confirmed its chemical structure to be 5,8-bis(2-methacryloyloxy-3-hydroxypropyloxy)quinoline.1 H NMR spectrum Figure 13 shown. 1 H NMR (600 MHz, CDCl3) δ 8.61 (dd, J = 3.5, 2.2 Hz, 1H), 8.45 (dd, J = 7.7, 2.2 Hz, 1H), 7.29 (dd, J = 7.9, 3.5 Hz, 1H), 7.11 (d, J = 8.4 Hz, 1H), 6.94 (d, J = 8.4 Hz,1H), 6.31 (ddq, J = 15.4, 2.0, 0.9 Hz, 2H), 5.89 (ddq, J = 14.6, 2.0, 0.9 Hz,2H), 4.51 – 4.42 (m, 4H), 4.32 – 4.22 (m, 3H), 4.19 – 4.12 (m, 1H), 4.12 –4.04 (m, 1H), 3.79 – 3.70 (m, 1H), 1.92 (d, J = 0.9 Hz, 6H).

[0080] The intermediate product 5 (53.5 g, 0.12 mol) was added to a dry 500 mL three-necked reaction vessel. The system temperature was controlled at 85°C, and PPA (115%, 84.5 g, 0.25 mol) was slowly added dropwise in three portions within 1 hour. The reaction was maintained for 3 hours. The system was then heated to 85°C, and 0.8 g of deionized water was slowly added for hydrolysis. Stirring was continued for 24 hours. After the reaction solution was cooled to room temperature, product 5 was obtained as a brown crystalline solid (yield 97%). The structure of product 5 was determined by 1 H NMR and 31 P NMR characterization confirmed that it was bis(methacryloyloxy)-3-phosphoglycerol quinoline. The specific characterization results are as follows: 1H NMR (600 MHz, CDCl3) δ 8.63 (dd, J = 3.5, 2.2 Hz, 1H), 7.53 (dd, J= 7.8, 2.2 Hz, 1H), 7.36 – 7.28 (m, 2H), 7.26 (d, J = 8.4 Hz, 1H), 6.33 (ddq,J = 15.4, 2.0, 0.9 Hz, 2H), 5.90 (ddq, J = 14.6, 2.0, 0.9 Hz, 2H), 5.16 –5.06 (m, 2H), 4.63 (dd, J = 11.3, 5.6 Hz, 2H), 4.44 (ddd, J = 11.4, 9.5, 5.4Hz, 3H), 4.39 – 4.29 (m, 2H), 4.25 (dd, J = 11.4, 5.6 Hz, 1H), 1.94 (t, J =1.0 Hz, 6H). 1 H NMR spectrum Figure 14 shown.

[0081] 31 P NMR (600 MHz, CDCl3) δ 1.97 (s, 2P). 31 P NMR spectrum is as follows Figure 15 shown.

[0082] Application Examples

[0083] To evaluate the performance of the bisphosphate functional monomers prepared in Examples 1-5 in metal anticorrosion coatings, the monomers of these examples were compared with the commercially available polyphosphate monomer PAM-200 in this application example. The emulsion and coating were prepared according to the following steps: 1. emulsion synthesis (1) Preparation of primer: Add butyl acrylate (45 g), styrene (15 g), deionized water (75 g) and ammonium persulfate (0.9 g) into a 500 mL reactor and stir at 300 rpm to mix evenly.

[0084] (2) Pre-emulsification: Butyl acrylate (60 g), styrene (30 g), deionized water (150 g), emulsifier SR-10 (0.85 g) and target functional monomer (3 g) were mixed and homogenized at high speed (10,000 rpm, 10 min) to obtain a stable pre-emulsion.

[0085] (3) Emulsion polymerization: The primer solution was heated to 85°C. After the system glowed blue, the pre-emulsion was added dropwise at a uniform rate (complete addition within 2 hours). The solution was heated to 90°C and aged for 1 hour. After cooling to 25°C, it was filtered (200 mesh) to obtain an acrylic emulsion containing a bisphosphate monomer. A total of six emulsions were prepared, using the bisphosphate functional monomers prepared in Examples 1-5 and PAM-200.

[0086] 2. Preparation of anti-corrosion coatings To each of the above emulsions (100 g), dispersant BYK-190 (2 g), wetting agent TEGO-4100 (0.5 g), defoamer BYK-1711 (0.5 g), and anti-flash rust agent Halox Flash-X150 (0.5 g) were added in sequence. After low-speed stirring (500 rpm, 10 min), titanium dioxide R-706 (20 g) and iron oxide red pigment (5 g) were added. High-speed dispersion (2000 rpm, 15 min) was performed, and finally, thickener ACRYSOL RM-8W (1 g) was added. The viscosity was adjusted to 100±5 KU (Stormer viscometer test) to obtain 6 anti-corrosion coatings.

[0087] 3. Coating preparation (1) Substrate treatment: Sandblasted Q235 carbon steel plate (size 150×70×1 mm), clean and dry.

[0088] (2) Spraying process: A SATA jet 5000 automatic spray gun was used, with the compressed air supply pressure adjusted to 0.4 MPa. The vertical distance between the spray gun nozzle and the substrate to be coated was maintained at 20 cm. During the spraying process, the spray gun movement was maintained as smooth and the distance as possible constant. The dry film thickness after multiple spray passes was controlled to 50 ± 2 μm by adjusting the spray speed and the overlap ratio of the spray width. The dry film thickness was measured after curing using an eddy current thickness gauge. The sprayed panels were then cured at room temperature for 7 days (168 hours) in a standard laboratory environment (temperature: 23 ± 2°C, relative humidity: 50 ± 10%). After 7 days of curing, the coatings were tested for adhesion and corrosion resistance according to relevant test standards.

[0089] 4. Comparative Testing (1) Coating adhesion test: The coatings formed using the bisphosphate functional monomers prepared in Examples 1-5 and the emulsion prepared using PAM200 in the comparative example were tested for adhesion according to GB / T 9286-2021 ("Cross-cut test for paint and varnish films"). A multi-blade cutter with a blade spacing of 1 mm, a blade angle of 30°, and a hardness of ≥ HRC 55 was used. A 25 mm wide tape with an adhesion of (10±1) N / 25 mm was used as the auxiliary material. After cutting a grid of specified spacing on the coating surface, the center of the tape was placed over the gridded area. The tape was pressed firmly with fingers to adhere completely, and allowed to stand for (90±30) seconds. The tape was then removed smoothly and quickly at an angle of approximately 60° within (0.5-1.0) seconds. Immediately after removal, the gridded area was observed under appropriate lighting conditions using a magnifying glass (e.g., 2x-3x magnification) to determine if any coating had fallen off. The test results are shown in Table 1.

[0090] Table 1

[0091] Observation revealed that coatings formulated with emulsions prepared using the bisphosphate functional monomers prepared in Examples 1-5 exhibited no film detachment in the cross-sectioned areas. According to the GB / T 9286-2021 standard, all coatings achieved the highest adhesion grade of 0 (completely smooth cut edges, no detachment within the grid). In contrast, coatings formed with the emulsion obtained in Comparative Example PAM200 exhibited detachment at the intersections and along the edges of the cuts, with the affected cross-section area exceeding 5% but not exceeding 15%, resulting in a grade of 2. This demonstrates that coatings formed using the functional monomers of the present invention exhibit significantly superior adhesion to those obtained with Comparative Example PAM200.

[0092] (2) Coating salt spray resistance test: For each coating formed by the emulsion obtained using the bisphosphate functional monomers prepared in Examples 1-5 and the PAM200 of the comparative example in the application examples, the salt spray resistance of each coating was evaluated in accordance with the standard GB / T 1771-2007 (Determination of Neutral Salt Spray Resistance of Paints and Varnishes), specifically as follows: two 50 mm long intersecting lines (angles 30°-60°) were scratched on the surface of the coating using a tungsten carbide tip, deep to the exposed metal substrate, with a scratch spacing of ≥25 mm. The scratched specimen was placed in a salt spray chamber at 35±1°C and sprayed with a 5% NaCl solution with a pH of 6.8 (sedimentation rate 1.5 mL / (h·80 cm²)). The specimen was tilted at 20 ± 5° (relative to the vertical) for 1000 h. The scratch extension width (measured under a microscope, with an accuracy of ±0.1 mm), rust grade (Ri, according to GB / T 30789.3-2014), and blister grade (GB / T 1766-2008) were recorded at 48-h intervals. The test results are shown in Table 2.

[0093] Table 2

[0094] Table 2 shows that the coatings formed using the emulsions prepared with the bisphosphate functional monomers of Examples 1-5 of the present invention exhibited corrosion extension widths of 0.6-1.2 mm, with corrosion grades Ri1-Ri3. Comparative Example PAM-200 exhibited corrosion extension widths greater than 3.0 mm, with a corrosion grade Ri5, and exhibited S4-level intensive blistering on the surface. This demonstrates that the coatings formed using the bisphosphate functional monomers of the present invention exhibit significantly better salt spray resistance than the comparative example PAM200.

[0095] The present invention has been described above in detail with reference to specific embodiments. These embodiments are merely illustrative and are not intended to limit the scope of protection of the present invention. Persons skilled in the art may make various modifications, variations, or substitutions to the present invention without departing from the spirit and scope of the present invention. Therefore, various equivalent variations made in accordance with the present invention are still within the scope of the present invention.

Claims

1. A biphenyl skeleton-containing bisphosphate functional monomer having the following general structural formula (I): （I） in, R 1 is H or CH3, R 2 is -C(O)-O- or -O, m and n are independently any natural numbers from 1 to 10; R is selected from one of the following groups: wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br.

2. The bisphosphate functional monomer according to claim 1, wherein m and n are independently selected from any natural numbers from 1 to 5.

3. The bisphosphate functional monomer according to claim 1, wherein R is selected from one of the following groups: 、 、 、 or .

4. The bisphosphate functional monomer according to claim 1, having the following structural formula: 、 、 、 or 。 5. An intermediate compound for preparing a bisphosphate functional monomer having the following general structural formula (II): (II) in, R 1 is H or CH3, R 2 is -C(O)-O- or -O, m and n are independently any natural numbers from 1 to 10; R is selected from one of the following groups: wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br.

6. The intermediate compound according to claim 5, wherein m and n are independently selected from any natural numbers from 1 to 5.

7. The intermediate compound according to claim 5 or 6, wherein R is selected from one of the following groups: 、 、 、 or .

8. The intermediate compound according to claim 5, which has the following structural formula: 、 、 、 or 。 9. The method for preparing a bisphosphate functional monomer according to any one of claims 1 to 4, comprising the steps of: (a) Epoxy ring-opening reaction: An aromatic or heteroaromatic compound having two phenolic hydroxyl groups and an ethylenically unsaturated monomer containing an epoxy group undergo a nucleophilic ring-opening reaction in the presence of a catalyst to form an intermediate compound having the general structural formula (II); Wherein, the aromatic or heteroaromatic compound having two phenolic hydroxyl groups is selected from one of the following compounds: wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; wherein X is H, CH3, F, Cl or Br; Wherein, the structure of the epoxy-containing ethylenically unsaturated monomer is shown in formula (III): (III) In formula (III), R 1 is H or CH3, R 2 is -C(O)-O- or -O, m and n are independently any natural numbers from 1 to 10; (b) Phosphorylation reaction: The intermediate compound of general formula (II) obtained in step (a) is subjected to a phosphorylation reaction to form a diphosphate functional monomer having a structure such as general formula (I).

10. The preparation method according to claim 9, wherein The aromatic or heteroaromatic compound having two phenolic hydroxyl groups has one of the following structural formulas: 、 、 、 、 、 、 、 、 。 11. The preparation method according to claim 9, wherein The epoxy-containing ethylenically unsaturated monomer has one of the following structural formulas: 、 、 、 、 、 、 、 。 12. Use of the bisphosphate functional monomer according to any one of claims 1 to 4 in the preparation of a metal anticorrosion emulsion.

13. A metal anticorrosion emulsion prepared using the bisphosphate functional monomer according to any one of claims 1 to 4. The metal anticorrosion emulsion according to claim 13 , wherein the emulsion is an acrylate emulsion and a copolymer emulsion thereof, an organosilicon-modified emulsion or a vinyl emulsion.

15. A method for forming a coating on a metal substrate, using a coating prepared from the metal anticorrosion emulsion according to claim 13 or 14.

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