Phosphate water-based polymer as well as preparation method and application thereof

Abstract

The invention provides a phosphate ester water-based polymer as well as a preparation method and application thereof. The phosphate ester water-based polymer is prepared by polymerizing the following monomers: monovinyl ether, a vinyl benzene monomer, allyl polyoxyethylene methyl terminated polyether and phosphorus pentoxide. The phosphate water-based polymer can be used for dispersing water-based nano titanium dioxide and can be used for preparing titanium dioxide dispersion liquid with low particle size, narrow distribution and good stability.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and relates to a phosphate ester water-based polymer and a preparation method and application thereof. Background Art

[0002] As a pigment dispersing aid, dispersant has the properties of reducing pigment particle size, increasing the gloss of the coating, improving leveling, and improving the coloring and hiding power of the coating. It is an important raw material that is indispensable in the production of coatings. Traditional dispersants are usually low molecular weight surfactants with relatively simple molecular structures and fewer anchoring groups. This structure is difficult to provide stable surface adsorption capacity and steric hindrance effect on pigment particles. Hyperdispersant is a high molecular weight dispersant with a more complex molecular structure, containing multiple and various types of anchoring groups and rich solvated segments. It can provide stable surface adsorption capacity of pigment particles and corresponding steric protection effect, forming a stable protection composition, effectively preventing the agglomeration and sedimentation of pigment particles.

[0003] As a special ionic group, the phosphate group has both hydrophilic and hydrophobic properties. When the phosphate group contacts the solid surface, its hydrophilic group adheres to the solid surface, while the hydrophobic group extends outward into the liquid, thereby reducing the surface tension of the liquid and making it easier for the liquid to spread on the solid surface to form a uniform coating. As a polymer dispersant containing a phosphate group, its unique structure can give the polymer excellent wetting, emulsification, solubilization and other properties. It effectively improves the dispersibility of the pigment, improves the uniformity of the material, prevents particle aggregation, and enhances the stability of the material.

[0004] Therefore, a polymer dispersant containing a phosphate group was developed, which has broad application prospects in the field of coatings. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a phosphate ester water-based polymer and a preparation method and application thereof.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a phosphate ester waterborne polymer, which is prepared by polymerizing the following monomers: monovinyl ether, vinylbenzene monomer, allyl polyoxyethylene methyl terminated polyether, and phosphorus pentoxide.

[0008] The phosphate ester aqueous polymer of the present invention can be used for dispersing aqueous nano titanium dioxide, and can prepare a titanium dioxide dispersion with low particle size, narrow distribution and good stability.

[0009] Preferably, the molar ratio of the monovinyl ether, vinylbenzene, allyl polyoxyethylene methyl terminated polyether, and phosphorus pentoxide is (1-2): (2-5): (3-5): (2-3). In the present invention, in the molar ratio, the molar ratio of the monovinyl ether 1-2 can be 1, 1.2, 1.4, 1.6, 1.8 or 2, the molar ratio of the vinylbenzene 2-5 can be 2, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.3, 4.5, 4.8 or 5, the molar ratio of the allyl polyoxyethylene methyl terminated polyether 3-5 can be 3, 3.3, 3.5, 3.8, 4, 4.3, 4.5, 4.8 or 5, and the molar ratio of the phosphorus pentoxide 2-3 can be 2, 2.3, 2.5, 2.8 or 3.

[0010] Preferably, the monovinyl ether is selected from one or a combination of at least two of ethylene glycol monovinyl ether, diethylene glycol monovinyl ether, and 4-hydroxybutyl vinyl ether.

[0011] Preferably, the vinylbenzene monomer is selected from one or a combination of at least two of styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene or α-methylstyrene.

[0012] Preferably, the allyl polyoxyethylene methyl terminated polyether has the following general formula: CH2=CHCH2O(CH2CH2O) n CH3, wherein n is an integer from 4 to 20 (e.g., 4, 6, 8, 10, 12, 15, 18 or 20, etc.).

[0013] Preferably, the polymerization is carried out under the initiation of an initiator.

[0014] Preferably, the initiator is selected from azo initiators.

[0015] Preferably, the amount of the azo initiator is 2-10% of the total mass of monovinyl ether, vinylbenzene monomer and allyl polyoxyethylene methyl terminated polyether, such as 2%, 3%, 5%, 8% or 10%.

[0016] Preferably, the azo initiator is selected from one or a combination of at least two of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile and dimethyl azobisisobutyrate.

[0017] Preferably, the weight average molecular weight of the phosphate ester aqueous polymer is 5000-20000 g / mol, for example 5000 g / mol, 6000 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, 12000 g / mol, 14000 g / mol, 16000 g / mol, 18000 g / mol or 20000 g / mol.

[0018] In the present invention, the molecular weight of the polymer is measured by gel permeation chromatography (GPC) using polyethylene oxide as a calibration standard and a water / acetonitrile mixed solution as an eluent.

[0019] On the other hand, the present invention provides a method for preparing the phosphate ester water-based polymer as described above, the preparation method comprising the following steps:

[0020] (1) mixing monovinyl ether, vinylbenzene and part of allyl polyoxyethylene methyl terminated polyether to obtain a mixed solution A, and dissolving an initiator in a solvent to obtain a mixed solution B;

[0021] (2) mixing the mixed solution A, the mixed solution B and the remaining allyl polyoxyethylene methyl terminated polyether, and reacting them to obtain an intermediate polymer;

[0022] (3) adding phosphorus pentoxide to the system containing the intermediate polymer obtained in step (2) to react and obtain the phosphate ester water-based polymer.

[0023] Preferably, the portion of allyl polyoxyethylene methyl terminated polyether in step (1) is 40-60% of the total mass of allyl polyoxyethylene methyl terminated polyether, for example 40%, 43%, 45%, 48%, 50%, 53%, 55%, 58% or 60%.

[0024] In the present invention, by first reacting monovinyl ether, vinylbenzene and part of the allyl polyoxyethylene methyl terminated polyether in step (1), and then reacting the mixed solution A and the mixed solution B with the remaining allyl polyoxyethylene methyl terminated polyether, the molecular weight of the polymer can be better controlled, and the copolymerization rate of the polymer can be adjusted, so that the polymerization rate is controllable, the polymerization product has good uniformity, and the reaction is prevented from being too fast and the polymerization molecular weight is too high.

[0025] Preferably, the initiator in step (1) is selected from azo initiators.

[0026] Preferably, the amount of the azo initiator is 2-10% of the total mass of monovinyl ether, vinylbenzene monomer and allyl polyoxyethylene methyl terminated polyether, such as 2%, 3%, 5%, 8% or 10%.

[0027] Preferably, the azo initiator is selected from one or a combination of at least two of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile and dimethyl azobisisobutyrate.

[0028] Preferably, the solvent in step (1) is selected from one or a combination of at least two of ethylene glycol dimethyl ether, ethylene glycol dipropyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether.

[0029] Preferably, in step (2), the mixed solution A and the mixed solution B are simultaneously added to the remaining allyl polyoxyethylene methyl terminated polyether and mixed to carry out a reaction.

[0030] Preferably, the adding method is dropwise addition.

[0031] Preferably, the dropping is completed within 1 to 4 hours (eg, 1 hour, 1.3 hours, 1.5 hours, 1.8 hours, 2 hours, 2.3 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours).

[0032] Preferably, before the mixing in step (2), the remaining allyl polyoxyethylene methyl terminated polyether is first heated to 60-100°C (e.g., 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C), and then mixed solution A and mixed solution B are added under stirring.

[0033] Preferably, the reaction temperature in step (2) is 60-100°C, for example 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, and the reaction time is 1-3 hours, for example 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours.

[0034] Preferably, in step (3), the temperature is controlled at 50-100° C. (e.g., 50° C., 60° C., 70° C., 80° C., 90° C. or 100° C.), phosphorus pentoxide is added to the system containing the intermediate polymer obtained in step (2), and then the reaction is kept warm for 3-10 hours (e.g., 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours).

[0035] Preferably, the phosphorus pentoxide is uniformly added to the system in batches within 1 to 3 hours (eg, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours).

[0036] On the other hand, the present invention provides an aqueous nano-titanium dioxide dispersion, wherein the aqueous nano-titanium dioxide dispersion comprises a dispersant, and the dispersant is the phosphate ester aqueous polymer as described above.

[0037] In the present invention, a phosphate-based aqueous polymer is used as a dispersant for aqueous nano-titanium dioxide, and a titanium dioxide dispersion with low particle size, narrow distribution and good stability can be obtained.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The phosphate ester aqueous polymer of the present invention can be used for dispersing aqueous nano titanium dioxide, and can prepare a titanium dioxide dispersion with low particle size, narrow distribution and good stability. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0041] Example 1

[0042] This embodiment provides a phosphate ester water-based polymer, and the preparation method of the polymer comprises the following steps:

[0043] The first step: 88g of ethylene glycol monovinyl ether, 210g of styrene and 800g of allyl polyoxyethylene methyl terminated polyether (Mw: 500g / mol) (Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.) are mixed uniformly to obtain a mixed solution A; 37g of azobisisobutyronitrile is dissolved in 185g of ethylene glycol dimethyl ether to obtain a mixed solution B.

[0044] Step 2: Add 800g of allyl polyoxyethylene methyl terminated polyether (Mw: 500g / mol) into a stirred, temperature-controlled, condensed reaction flask, and heat it to 60°C; under stirring, simultaneously add the mixed solutions A and B dropwise into the flask within 2 hours, and keep warm for 1.5 hours after the addition is complete to obtain an intermediate polymer.

[0045] Step 3: Control the reaction temperature to 50°C, and add 284g of phosphorus pentoxide into the flask in batches evenly within 1 hour according to the proportion; after the addition is completed, keep the temperature for reaction for 3 hours (sample and measure the acid value change difference every ten minutes <5mgKOH / g, which is regarded as the reaction end point) to obtain the final phosphate ester water-based polymer dispersant.

[0046] The molecular weight of the polymers was measured by gel permeation chromatography (GPC) using polyethylene oxide as a calibration standard and a water / acetonitrile mixed solution as an eluent, and the weight average molecular weight was 19357 g / mol.

[0047] Example 2

[0048] The first step: 132g of ethylene glycol monovinyl ether, 312g of styrene and 850g of allyl polyoxyethylene methyl terminated polyether (Mw: 350g / mol) (Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.) were mixed to obtain a mixed solution A; 260g of azobisisovaleronitrile was dissolved in 2300g of diethylene glycol dimethyl ether solvent to obtain a mixed solution B.

[0049] Step 2: Add the remaining 850g of allyl polyoxyethylene methyl terminated polyether (Mw: 350g / mol) into a stirred, temperature-controlled, condensed reaction flask, and heat it to 90°C; under stirring, simultaneously add the mixed solutions A and B dropwise into the flask within 4 hours, and keep warm for 3 hours after the addition is complete to obtain an intermediate polymer.

[0050] Step 3: Control the reaction temperature at 100°C, and add 220g of phosphorus pentoxide into the flask in batches evenly within 3 hours according to the proportion; after the addition is completed, keep the temperature for reaction for 10 hours (sample and measure the acid value change difference every ten minutes <5mgKOH / g, which is regarded as the reaction end point) to obtain the final phosphate ester water-based polymer dispersant.

[0051] The molecular weight of the polymers was measured by gel permeation chromatography (GPC) using polyethylene oxide as a calibration standard and a water / acetonitrile mixed solution as an eluent, and the weight average molecular weight was 7584 g / mol.

[0052] Example 3

[0053] The first step: 233g 4-hydroxybutyl vinyl ether, 591g 2-methylstyrene and 750g allyl polyoxyethylene methyl terminated polyether (Mw: 500g / mol) (Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.) were mixed to obtain a mixed solution A; 450g azobisisoheptanenitrile was dissolved in 4500g tetraethylene glycol dimethyl ether solvent to obtain a mixed solution B.

[0054] Step 2: Add 750g of allyl polyoxyethylene methyl terminated polyether (Mw: 500g / mol) into a stirred, temperature-controlled, condensed reaction flask, and heat it to 100°C; under stirring, simultaneously add the mixed solutions A and B dropwise into the flask within 4 hours, and keep warm for 1 hour after the addition is complete to obtain an intermediate polymer.

[0055] Step 3: Control the reaction temperature at 100°C, and add phosphorus pentoxide into the flask in batches evenly within 1 hour according to the proportion; after the addition is completed, keep the temperature for reaction for 3 hours, take samples every ten minutes to measure the acid value change difference <5mgKOH / g, which is regarded as the reaction end point, and the final phosphate ester water-based polymer dispersant is obtained.

[0056] The molecular weight of the polymers was measured by gel permeation chromatography (GPC) using polyethylene oxide as a calibration standard and a water / acetonitrile mixed solution as an eluent, and the weight average molecular weight was 10553 g / mol.

[0057] Example 4

[0058] This embodiment provides a phosphate ester water-based polymer, and the preparation method of the polymer comprises the following steps:

[0059] The first step: 260g of diethylene glycol monovinyl ether, 472g of α-methylstyrene and 1000g of allyl polyoxyethylene methyl terminated polyether (Mw: 500g / mol) (Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.) are mixed evenly to obtain a mixed solution A; 283g of azobisisoheptanenitrile is dissolved in 2000g of ethylene glycol dipropyl ether solvent to obtain a mixed solution B.

[0060] Step 2: Add the remaining 1000g of allyl polyoxyethylene methyl terminated polyether (Mw: 500g / mol) into a stirred, temperature-controlled, condensed reaction flask, and heat it to 90°C; under stirring, simultaneously add the mixed solutions A and B dropwise into the flask within 2 hours, and keep warm for 2 hours after the addition is complete to obtain an intermediate polymer.

[0061] Step 3: Control the reaction temperature to 80°C, and add phosphorus pentoxide into the flask in batches evenly within 2.5 hours according to the proportion; after the addition is completed, keep the temperature for reaction for 5 hours, take samples every ten minutes to measure the acid value change difference <5mgKOH / g, which is regarded as the reaction end point, and the final phosphate ester water-based polymer dispersant is obtained.

[0062] The molecular weight of the polymers was measured by gel permeation chromatography (GPC) using polyethylene oxide as a calibration standard and a water / acetonitrile mixed solution as an eluent, and the weight average molecular weight was 14691 g / mol.

[0063] Comparative Example 1

[0064] The only difference from Example 1 is that styrene monomer is not included in the preparation, and the weight average molecular weight of the prepared polymer is 17891 g / mol.

[0065] Comparative Example 2

[0066] The only difference from Example 1 is that ethylene glycol monovinyl ether is replaced by an equal molar amount of ethyl vinyl ether, and the weight average molecular weight of the prepared polymer is 15493 g / mol.

[0067] Comparative Example 3

[0068] The only difference from Example 1 is that styrene is replaced by an equal molar amount of 2-vinylnaphthalene, and the weight average molecular weight of the prepared polymer is 11583 g / mol.

[0069] Comparative Example 4

[0070] The only difference from Example 1 is that allyl polyoxyethylene methyl terminated polyether (Mw: 500 g / mol) is not included in the preparation, and the weight average molecular weight of the prepared polymer is 8754 g / mol.

[0071] Comparative Example 5

[0072] The only difference from Example 1 is that the amount of ethylene glycol monovinyl ether added in the preparation is 20 g, and the weight average molecular weight of the prepared polymer is 13532 g / mol.

[0073] Comparative Example 6

[0074] The only difference from Example 1 is that the amount of phosphorus pentoxide added in the preparation is 74 g, and the weight average molecular weight of the prepared polymer is 17834 g / mol.

[0075] Test Case

[0076] The polymers obtained in the examples and comparative examples were used to disperse aqueous nano-titanium dioxide.

[0077] By laboratory sand grinding, the total amount of the slurry formula is 100 parts, and the polymer dispersant, pH stabilizer monoethanolamine, and 20nm-nano titanium dioxide prepared in Examples 1-4 and Comparative Examples 1-4 are added in proportion; after stirring evenly, 200g of zirconium beads with a particle size of 1-1.2mm are added and sealed in a glass jar, shaken for 10 hours, and filtered to obtain a color paste. The viscosity, particle size, and storage stability of the color paste are tested.

[0078] The formula is shown in Table 1 below.

[0079] Table 1

[0080]

[0081] 1. Particle size: tested using BT-90 laser particle size analyzer, Dandong Better Instrument Co., Ltd.

[0082] 2. Storage stability: Store at 55°C for 7 days and detect the change in particle size.

[0083] The specific test results are shown in Table 2 below.

[0084] Table 2

[0085]

[0086] As can be seen from the above test results, the phosphate ester aqueous polymer prepared in the present invention can be used as a dispersant for aqueous nano titanium dioxide to obtain a titanium dioxide dispersion with low particle size, narrow distribution and good stability.

[0087] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the phosphate ester water-based polymer and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A phosphate ester water-based polymer, characterized in that: The phosphate ester water-based polymer is prepared by polymerizing the following monomers: monovinyl ether, vinyl benzene monomer, allyl polyoxyethylene methyl terminated polyether, and phosphorus pentoxide.

2. The phosphate ester water-based polymer according to claim 1, characterized in that: The molar ratio of monovinyl ether, vinylbenzene, allyl polyoxyethylene methyl terminated polyether and phosphorus pentoxide is (1-2): (2-5): (3-5): (2-3).

3. The phosphate ester water-based polymer according to claim 1 or 2, characterized in that: The monovinyl ether is selected from one or a combination of at least two of ethylene glycol monovinyl ether, diethylene glycol monovinyl ether, and 4-hydroxybutyl vinyl ether; Preferably, the vinylbenzene monomer is selected from one or a combination of at least two of styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene or α-methylstyrene; Preferably, the allyl polyoxyethylene methyl terminated polyether has the following general formula: CH2=CHCH2O(CH2CH2O) n CH3, wherein n is an integer from 4 to 20.

4. The phosphate ester water-based polymer according to any one of claims 1 to 3, characterized in that: The polymerization is carried out under the initiation of an initiator; Preferably, the initiator is selected from azo initiators; Preferably, the amount of the azo initiator is 2-10% of the total mass of monovinyl ether, vinylbenzene monomer and allyl polyoxyethylene methyl terminated polyether; Preferably, the azo initiator is selected from one or a combination of at least two of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile and dimethyl azobisisobutyrate.

5. The phosphate ester water-based polymer according to any one of claims 1 to 4, characterized in that: The weight average molecular weight of the phosphate ester water-based polymer is 5000 to 20000 g / mol.

6. The method for preparing a phosphate ester water-based polymer according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) mixing monovinyl ether, vinylbenzene and part of allyl polyoxyethylene methyl terminated polyether to obtain a mixed solution A, and dissolving an initiator in a solvent to obtain a mixed solution B; (2) mixing the mixed solution A, the mixed solution B and the remaining allyl polyoxyethylene methyl terminated polyether, and reacting them to obtain an intermediate polymer; (3) adding phosphorus pentoxide to the system containing the intermediate polymer obtained in step (2) to react and obtain the phosphate ester water-based polymer.

7. The preparation method according to claim 6, characterized in that: The part of allyl polyoxyethylene methyl terminated polyether in step (1) accounts for 40 to 60% of the total mass of allyl polyoxyethylene methyl terminated polyether.

8. The preparation method according to claim 6, characterized in that: The initiator in step (1) is selected from azo initiators; Preferably, the amount of the azo initiator is 2-10% of the total mass of monovinyl ether, vinylbenzene monomer and allyl polyoxyethylene methyl terminated polyether; Preferably, the azo initiator is selected from one or a combination of at least two of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile and dimethyl azobisisobutyrate.

9. The preparation method according to claim 6, characterized in that: The solvent in step (1) is selected from one or a combination of at least two of ethylene glycol dimethyl ether, ethylene glycol dipropyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether; Preferably, in step (2), the mixed solution A and the mixed solution B are simultaneously added to the remaining allyl polyoxyethylene methyl terminated polyether and mixed to react; Preferably, the adding method is dropwise addition; Preferably, the dripping is completed within 1 to 4 hours; Preferably, before the mixing in step (2), the remaining allyl polyoxyethylene methyl terminated polyether is first heated to 60-100° C., and then mixed solution A and mixed solution B are added under stirring; Preferably, the reaction temperature in step (2) is 60 to 100° C., and the reaction time is 1 to 3 hours; Preferably, in step (3), the temperature is controlled at 50 to 100° C., phosphorus pentoxide is added to the system containing the intermediate polymer obtained in step (2), and then the reaction is carried out by heat preservation for 3 to 10 hours; Preferably, the phosphorus pentoxide is added to the system uniformly in batches within 1 to 3 hours.

10. An aqueous nano titanium dioxide dispersion, characterized in that: The aqueous nano-titanium dioxide dispersion includes a dispersant, and the dispersant is a phosphate-based aqueous polymer as described in any one of claims 1 to 5.

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