Water-based paint containing modified polyurethane and preparation method thereof

Abstract

The invention relates to the technical field of water-based paint, and discloses water-based paint containing modified polyurethane and a preparation method thereof.The modified polyurethane, silicon-containing benzoxazine, water-based acrylic resin, a polyether modified organic silicon defoaming agent, a propylene glycol film-forming agent and water are added into a stirrer and stirred, and the water-based paint containing the modified polyurethane is obtained after stirring is finished. The benzoxazine structure in the silicon-containing benzoxazine can form a heat-resistant phenolic resin structure at a high temperature, so that the water-based paint shows higher thermal decomposition temperature, and the benzoxazine structure is good in heat resistance and high in char forming property and has a better flame-retardant effect; wherein the fluorine element is introduced into the water-based paint, so that a smooth fluorine carbonization layer which is not easy to attach with an object can be formed on the surface of the water-based paint, and therefore, the water-based paint has a relatively good self-cleaning effect; the silicon element can absorb a large amount of heat when being heated, the temperature of the material is reduced, the combustion speed is slowed down, and the flame-retardant effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of water-based paints, in particular to a water-based paint containing modified polyurethane and a preparation method thereof. Background Art

[0002] Water-based paint is a paint that uses water as a diluent. It has environmentally friendly characteristics such as low odor and low volatile organic compounds, and is widely used in furniture, machinery and other industries. When water-based polyurethane paint is used for leather finishing, it has good leveling properties, good film-forming properties, and the coating is cold-resistant, heat-resistant, wear-resistant, and elastic. However, when encountering a fire, it is easy to burn and has a great safety hazard. Therefore, how to avoid this phenomenon is the key to solving the problem. For example, patent CN108753145A discloses a polyurethane water-based paint and a preparation method thereof. The water-based paint of the invention has the advantages of good stability, strong adhesion, weather resistance and strong UV resistance, but its flame retardant and self-cleaning properties are not improved. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the deficiencies of the prior art, the present invention provides a water-based paint containing modified polyurethane and a preparation method thereof, which has good flame retardant and self-cleaning effects.

[0005] (II) Technical solution

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a water-based paint containing modified polyurethane, comprising the following components by weight: 5-10 parts by weight of modified polyurethane, 3-6 parts by weight of silicon-containing benzoxazine, 8-14 parts by weight of water-based acrylic resin, 1-2 parts by weight of polyether-modified silicone defoamer, 0.8-1.3 parts by weight of propylene glycol film-forming agent, and 20-30 parts by weight of water.

[0007] Preferably, the preparation method of the modified polyurethane is:

[0008] (1) adding 1,6-hexanediamine and terephthalaldehyde to an ethyl acetate solvent, stirring and dissolving, and carrying out a condensation reaction at 65-80° C. for 6-9 hours, and then continuously adding hexamethyldisilazane thereto, carrying out an addition reaction at 70-90° C. for 10-12 hours, and after the reaction is completed, carrying out reduced pressure distillation, and washing with ether to obtain a tertiary aminosilane;

[0009] (2) adding sodium 3-chloro-2-hydroxypropanesulfonate and tertiary aminosilane to a mixed solvent of ethanol and water, heating to 80-100° C. for reaction for 7-9 hours, washing with petroleum ether, and rotary evaporation to obtain a sulfonic acid chain extender;

[0010] (3) Toluene diisocyanate and polyether polyol are added to a reaction kettle, and then dibutyltin dilaurate is added, and nitrogen protection is introduced. The reaction is carried out at 70-95° C. for 7-10 hours to perform prepolymerization, and then a sulfonic acid chain extender is added and stirred to perform a chain extension reaction. After the reaction is completed, the mixture is naturally cooled and discharged to obtain a modified polyurethane.

[0011] Preferably, the mass ratio of 1,6-hexanediamine, terephthalaldehyde and hexamethyldisilazane in (1) is 0.8-1.3:1:1.1-1.3.

[0012] Preferably, the mass ratio of sodium 3-chloro-2-hydroxypropanesulfonate to tertiary aminosilane in (2) is 1.2-1.4:1.

[0013] Preferably, the mass ratio of toluene diisocyanate, polyether polyol, dibutyltin dilaurate and sulfonic acid chain extender in (3) is 1:1.3-1.6:0.01-0.03:0.6-0.8.

[0014] Preferably, the preparation method of the silicon-containing benzoxazine is:

[0015] S1. Add the sulfonic acid chain extender, the aqueous solution of formaldehyde, and 2-(4-hydroxyphenyl)isopropanol to a toluene solvent, fully dissolve them, and carry out a cyclization reaction at 70-90° C. for 10-16 hours. After the reaction, distill under reduced pressure, wash with deionized water, and recrystallize the crude product from dichloromethane to obtain a hydroxylated benzoxazine;

[0016] S2. Add perfluorooctanoyl chloride and hydroxylated benzoxazine to N,N-dimethylformamide solvent, and then continue to add triethylamine catalyst to carry out reaction. After the reaction is completed, remove the solvent by vacuum distillation, wash, and recrystallize to obtain silicon-containing benzoxazine.

[0017] Preferably, the mass ratio of the sulfonic acid chain extender, the formaldehyde aqueous solution, and the 2-(4-hydroxyphenyl)isopropanol in S1 is 1:1.3-1.5:1.2-1.6.

[0018] Preferably, the mass ratio of the S2 perfluorooctanoyl chloride, hydroxylated benzoxazine, and triethylamine catalyst is 1.2-1.5:1:0.02-0.03.

[0019] Preferably, the preparation method of the water-based paint containing modified polyurethane is: adding modified polyurethane, silicon-containing benzoxazine, water-based acrylic resin, polyether-modified silicone defoamer, propylene glycol film-forming agent, and water into a stirrer, stirring for 10-20 minutes, and then obtaining the water-based paint containing modified polyurethane.

[0020] (III) Beneficial technical effects

[0021] The invention provides a water-based paint containing modified polyurethane by adding modified polyurethane, silicon-containing benzoxazine, water-based acrylic resin, polyether-modified organic silicon defoamer, propylene glycol film-forming agent and water into a stirrer and stirring the mixture.

[0022] The benzoxazine structure in the silicon-containing benzoxazine of the present invention will form a heat-resistant phenolic resin structure at high temperature, so that the water-based paint shows a higher thermal decomposition temperature. The benzoxazine structure has good heat resistance and high carbonization property, and has a good flame retardant effect. The fluorine element introduced into the water-based paint can form a smooth fluorocarbon layer on the surface of the paint that is not easy to adhere to objects, so it has a good self-cleaning effect. The quaternary ammonium salt contained in the modified polyurethane and the silicon-containing benzoxazine also has a good self-cleaning effect. The sodium sulfonate group in the modified polyurethane also has a good flame retardant effect. The silicon element in the present invention absorbs a large amount of heat when heated, reduces the temperature of the material, slows down the combustion speed, and has a flame retardant effect. DETAILED DESCRIPTION

[0023] Example 1

[0024] (1) adding 1,6-hexanediamine and terephthalaldehyde to an ethyl acetate solvent, stirring and dissolving, condensing the mixture at 65° C. for 6 h, and then continuously adding hexamethyldisilazane, wherein the mass ratio of 1,6-hexanediamine, terephthalaldehyde and hexamethyldisilazane is 0.8:1:1.1, and reacting the mixture at 70° C. for 10 h. After the reaction is completed, performing distillation under reduced pressure, and washing with ether to obtain tertiary aminosilane;

[0025] (2) adding sodium 3-chloro-2-hydroxypropanesulfonate and tertiary aminosilane to a mixed solvent of ethanol and water, wherein the mass ratio of sodium 3-chloro-2-hydroxypropanesulfonate to tertiary aminosilane is 1.2:1, heating to 80° C. for reaction for 7 h, washing with petroleum ether after reaction, and rotary evaporation to obtain a sulfonic acid chain extender;

[0026] (3) adding toluene diisocyanate and polyether polyol to a reactor, then adding dibutyltin dilaurate, introducing nitrogen protection, reacting at 70° C. for 7 hours, performing prepolymerization, and then adding a sulfonic acid chain extender, wherein the mass ratio of toluene diisocyanate, polyether polyol, dibutyltin dilaurate, and sulfonic acid chain extender is 1:1.3:0.01:0.6, stirring for chain extension reaction, and after the reaction is completed, naturally cooling and discharging to obtain a modified polyurethane;

[0027] (4) adding a sulfonic acid chain extender, an aqueous solution of formaldehyde, and 2-(4-hydroxyphenyl)isopropanol to a toluene solvent, wherein the mass ratio of the sulfonic acid chain extender, the aqueous solution of formaldehyde, and the 2-(4-hydroxyphenyl)isopropanol is 1:1.3:1.2, and fully dissolving them to carry out a cyclization reaction at 70° C. for 10 hours. After the reaction, distillation under reduced pressure is performed, the product is washed with deionized water, and the crude product is recrystallized from dichloromethane to obtain a hydroxylated benzoxazine;

[0028] (5) adding perfluorooctanoyl chloride and hydroxylated benzoxazine to N,N-dimethylformamide solvent, and then continuing to add triethylamine catalyst thereto, wherein the mass ratio of perfluorooctanoyl chloride, hydroxylated benzoxazine, and triethylamine catalyst is 1.2:1:0.02, and reacting, and after the reaction is completed, removing the solvent by distillation under reduced pressure, washing, and recrystallizing to obtain silicon-containing benzoxazine;

[0029] (6) 5 parts by weight of modified polyurethane, 3 parts by weight of silicon-containing benzoxazine, 8 parts by weight of water-based acrylic resin, 1 part by weight of polyether-modified silicone defoamer, 0.8 parts by weight of propylene glycol film-forming agent, and 20 parts by weight of water are added into a stirrer and stirred for 10 minutes to obtain a water-based paint containing modified polyurethane.

[0030] Example 2

[0031] (1) adding 1,6-hexanediamine and terephthalaldehyde to an ethyl acetate solvent, stirring and dissolving, condensing the mixture at 80° C. for 9 h, and then continuously adding hexamethyldisilazane, wherein the mass ratio of 1,6-hexanediamine, terephthalaldehyde and hexamethyldisilazane is 1.3:1:1.3, and reacting the mixture at 90° C. for 12 h. After the reaction is completed, performing vacuum distillation, washing with ether, and obtaining tertiary aminosilane;

[0032] (2) adding sodium 3-chloro-2-hydroxypropanesulfonate and tertiary aminosilane to a mixed solvent of ethanol and water, wherein the mass ratio of sodium 3-chloro-2-hydroxypropanesulfonate to tertiary aminosilane is 1.4:1, heating to 100° C. for 9 hours, washing with petroleum ether after the reaction, and rotary evaporation to obtain a sulfonic acid chain extender;

[0033] (3) adding toluene diisocyanate and polyether polyol to a reactor, then adding dibutyltin dilaurate, introducing nitrogen protection, reacting at 95° C. for 10 hours, performing prepolymerization, and then adding a sulfonic acid chain extender, wherein the mass ratio of toluene diisocyanate, polyether polyol, dibutyltin dilaurate, and sulfonic acid chain extender is 1:1.6:0.03:0.8, stirring for chain extension reaction, and after the reaction is completed, naturally cooling and discharging to obtain a modified polyurethane;

[0034] (4) adding a sulfonic acid chain extender, an aqueous solution of formaldehyde, and 2-(4-hydroxyphenyl)isopropanol to a toluene solvent, wherein the mass ratio of the sulfonic acid chain extender, the aqueous solution of formaldehyde, and the 2-(4-hydroxyphenyl)isopropanol is 1:1.5:1.6, and fully dissolving them to carry out a cyclization reaction at 90° C. for 16 hours. After completion, the reaction is carried out by vacuum distillation, washing with deionized water, and recrystallizing the crude product from dichloromethane to obtain a hydroxylated benzoxazine;

[0035] (5) adding perfluorooctanoyl chloride and hydroxylated benzoxazine to N,N-dimethylformamide solvent, and then continuing to add triethylamine catalyst thereto, wherein the mass ratio of perfluorooctanoyl chloride, hydroxylated benzoxazine, and triethylamine catalyst is 1.5:1:0.03, and reacting, and after the reaction is completed, removing the solvent by reduced pressure distillation, washing, and recrystallizing to obtain silicon-containing benzoxazine;

[0036] (6) 10 parts by weight of modified polyurethane, 6 parts by weight of silicon-containing benzoxazine, 14 parts by weight of water-based acrylic resin, 2 parts by weight of polyether-modified silicone defoamer, 1.3 parts by weight of propylene glycol film-forming agent, and 30 parts by weight of water are added into a stirrer and stirred for 20 minutes to obtain a water-based paint containing modified polyurethane.

[0037] Example 3

[0038] (1) adding 1,6-hexanediamine and terephthalaldehyde to an ethyl acetate solvent, stirring and dissolving, condensing the mixture at 72.5° C. for 7.5 hours, and then continuously adding hexamethyldisilazane, wherein the mass ratio of 1,6-hexanediamine, terephthalaldehyde and hexamethyldisilazane is 1.05:1:1.2, and reacting the mixture at 80° C. for 11 hours. After the reaction is completed, performing vacuum distillation, washing with ether, and obtaining tertiary aminosilane;

[0039] (2) adding sodium 3-chloro-2-hydroxypropanesulfonate and tertiary aminosilane to a mixed solvent of ethanol and water, wherein the mass ratio of sodium 3-chloro-2-hydroxypropanesulfonate to tertiary aminosilane is 1.3:1, heating to 90° C. for reaction for 8 h, washing with petroleum ether after reaction, and rotary evaporation to obtain a sulfonic acid chain extender;

[0040] (3) adding toluene diisocyanate and polyether polyol to a reactor, then adding dibutyltin dilaurate, introducing nitrogen protection, reacting at 82.5° C. for 8.5 hours for prepolymerization, and then adding a sulfonic acid chain extender, wherein the mass ratio of toluene diisocyanate, polyether polyol, dibutyltin dilaurate, and sulfonic acid chain extender is 1:1.45:0.02:0.7, stirring for chain extension reaction, and after the reaction is completed, naturally cooling and discharging to obtain a modified polyurethane;

[0041] (4) adding a sulfonic acid chain extender, an aqueous solution of formaldehyde, and 2-(4-hydroxyphenyl)isopropanol to a toluene solvent, wherein the mass ratio of the sulfonic acid chain extender, the aqueous solution of formaldehyde, and the 2-(4-hydroxyphenyl)isopropanol is 1:1.4:1.4, and fully dissolving them to carry out a cyclization reaction at 80° C. for 13 hours. After the reaction, the reaction is carried out under reduced pressure distillation, washed with deionized water, and the crude product is recrystallized from dichloromethane to obtain a hydroxylated benzoxazine;

[0042] (5) adding perfluorooctanoyl chloride and hydroxylated benzoxazine to N,N-dimethylformamide solvent, and then continuing to add triethylamine catalyst thereto, wherein the mass ratio of perfluorooctanoyl chloride, hydroxylated benzoxazine, and triethylamine catalyst is 1.35:1:0.025, and reacting, and after the reaction is completed, removing the solvent by distillation under reduced pressure, washing, and recrystallizing to obtain silicon-containing benzoxazine;

[0043] (6) 7.5 parts by weight of modified polyurethane, 4.5 parts by weight of silicon-containing benzoxazine, 11 parts by weight of water-based acrylic resin, 1.5 parts by weight of polyether-modified silicone defoamer, 1.05 parts by weight of propylene glycol film-forming agent, and 25 parts by weight of water are added to a stirrer and stirred for 15 minutes to obtain a water-based paint containing modified polyurethane.

[0044] Example 4

[0045] (1) adding 1,6-hexanediamine and terephthalaldehyde to an ethyl acetate solvent, stirring and dissolving, condensing the mixture at 65° C. for 6 h, and then continuously adding hexamethyldisilazane, wherein the mass ratio of 1,6-hexanediamine, terephthalaldehyde and hexamethyldisilazane is 0.8:1:1.1, and reacting the mixture at 70° C. for 10 h. After the reaction is completed, performing distillation under reduced pressure, and washing with ether to obtain tertiary aminosilane;

[0046] (2) adding sodium 3-chloro-2-hydroxypropanesulfonate and tertiary aminosilane to a mixed solvent of ethanol and water, wherein the mass ratio of sodium 3-chloro-2-hydroxypropanesulfonate to tertiary aminosilane is 1.2:1, heating to 80° C. for reaction for 7 h, washing with petroleum ether after reaction, and rotary evaporation to obtain a sulfonic acid chain extender;

[0047] (3) adding toluene diisocyanate and polyether polyol to a reactor, then adding dibutyltin dilaurate, introducing nitrogen protection, reacting at 95° C. for 10 hours, performing prepolymerization, and then adding a sulfonic acid chain extender, wherein the mass ratio of toluene diisocyanate, polyether polyol, dibutyltin dilaurate, and sulfonic acid chain extender is 1:1.6:0.03:0.8, stirring for chain extension reaction, and after the reaction is completed, naturally cooling and discharging to obtain a modified polyurethane;

[0048] (4) adding a sulfonic acid chain extender, an aqueous solution of formaldehyde, and 2-(4-hydroxyphenyl)isopropanol to a toluene solvent, wherein the mass ratio of the sulfonic acid chain extender, the aqueous solution of formaldehyde, and the 2-(4-hydroxyphenyl)isopropanol is 1:1.5:1.6, and fully dissolving them to carry out a cyclization reaction at 90° C. for 16 hours. After completion, the reaction is carried out by vacuum distillation, washing with deionized water, and recrystallizing the crude product from dichloromethane to obtain a hydroxylated benzoxazine;

[0049] (5) adding perfluorooctanoyl chloride and hydroxylated benzoxazine to N,N-dimethylformamide solvent, and then continuing to add triethylamine catalyst thereto, wherein the mass ratio of perfluorooctanoyl chloride, hydroxylated benzoxazine, and triethylamine catalyst is 1.35:1:0.025, and reacting, and after the reaction is completed, removing the solvent by distillation under reduced pressure, washing, and recrystallizing to obtain silicon-containing benzoxazine;

[0050] (6) 7.5 parts by weight of modified polyurethane, 4.5 parts by weight of silicon-containing benzoxazine, 11 parts by weight of water-based acrylic resin, 1.5 parts by weight of polyether-modified silicone defoamer, 1.05 parts by weight of propylene glycol film-forming agent, and 25 parts by weight of water are added to a stirrer and stirred for 15 minutes to obtain a water-based paint containing modified polyurethane.

[0051] Comparative Example 1

[0052] The difference between this comparative example and Example 4 is that no modified polyurethane is added.

[0053] Comparative Example 2

[0054] Compared with Example 4, this comparative example is characterized in that no silicon-containing benzoxazine is added.

[0055] The surface wettability of the samples of Examples 1-4 and Comparative Examples 1-2 was characterized according to JC2000D, and contact angle tests were performed.

[0056] Table 1: Contact angle tests.

[0057]

[0058] As can be seen from Table 1, compared with Comparative Examples 1-2, the contact angles of Examples 1-4 are larger, resulting in the water droplets being unable to spread and being very easy to slide, indicating that the water-based paint prepared by the present invention has a self-cleaning function, and the self-cleaning function is good.

[0059] The limiting oxygen index of the material was tested using an oxygen index meter, and the combustion grade of the material was tested using a horizontal and vertical combustion instrument. The test results are shown in Table 2.

[0060] Table 2: Flame retardancy test.

[0061]

[0062] It can be seen from Table 2 that Examples 1-4 of the present invention have better flame retardant effects than Comparative Examples 1-2.

[0063] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A water-based paint containing modified polyurethane, characterized in that: The invention comprises the following components by weight: 5-10 parts by weight of modified polyurethane, 3-6 parts by weight of silicon-containing benzoxazine, 8-14 parts by weight of water-based acrylic resin, 1-2 parts by weight of polyether-modified organic silicon defoamer, 0.8-1.3 parts by weight of propylene glycol film-forming agent and 20-30 parts by weight of water.

2. The water-based paint containing modified polyurethane according to claim 1, characterized in that: The preparation method of the modified polyurethane is: (1) adding 1,6-hexanediamine and terephthalaldehyde to an ethyl acetate solvent, stirring and dissolving, and carrying out a condensation reaction at 65-80° C. for 6-9 hours, and then continuously adding hexamethyldisilazane thereto, carrying out an addition reaction at 70-90° C. for 10-12 hours, and after the reaction is completed, carrying out reduced pressure distillation, and washing with ether to obtain a tertiary aminosilane; (2) adding sodium 3-chloro-2-hydroxypropanesulfonate and tertiary aminosilane to a mixed solvent of ethanol and water, heating to 80-100° C. for reaction for 7-9 hours, washing with petroleum ether, and rotary evaporation to obtain a sulfonic acid chain extender; (3) Toluene diisocyanate and polyether polyol are added to a reaction kettle, and then dibutyltin dilaurate is added, and nitrogen protection is introduced. The reaction is carried out at 70-95° C. for 7-10 hours to perform prepolymerization, and then a sulfonic acid chain extender is added and stirred to perform a chain extension reaction. After the reaction is completed, the mixture is naturally cooled and discharged to obtain a modified polyurethane.

3. The water-based paint containing modified polyurethane according to claim 2, characterized in that: The mass ratio of 1,6-hexanediamine, terephthalaldehyde and hexamethyldisilazane in (1) is 0.8-1.3:1:1.1-1.

3.

4. The water-based paint containing modified polyurethane according to claim 2, characterized in that: The mass ratio of sodium 3-chloro-2-hydroxypropanesulfonate to tertiary aminosilane in (2) is 1.2-1.4:

1.

5. The water-based paint containing modified polyurethane according to claim 2, characterized in that: The mass ratio of toluene diisocyanate, polyether polyol, dibutyltin dilaurate and sulfonic acid chain extender in (3) is 1:1.3-1.6:0.01-0.03:0.6-0.

8.

6. The water-based paint containing modified polyurethane according to claim 1, characterized in that: The preparation method of the silicon-containing benzoxazine is: S1. Add the sulfonic acid chain extender, the aqueous solution of formaldehyde, and 2-(4-hydroxyphenyl)isopropanol to a toluene solvent, fully dissolve them, and carry out a cyclization reaction at 70-90° C. for 10-16 hours. After the reaction, distill under reduced pressure, wash with deionized water, and recrystallize the crude product from dichloromethane to obtain a hydroxylated benzoxazine; S2. Add perfluorooctanoyl chloride and hydroxylated benzoxazine to N,N-dimethylformamide solvent, and then continue to add triethylamine catalyst to carry out reaction. After the reaction is completed, remove the solvent by vacuum distillation, wash, and recrystallize to obtain silicon-containing benzoxazine.

7. The water-based paint containing modified polyurethane according to claim 6, characterized in that: The mass ratio of the sulfonic acid chain extender, the formaldehyde aqueous solution, and 2-(4-hydroxyphenyl)isopropanol in S1 is 1:1.3-1.5:1.2-1.

6.

8. The water-based paint containing modified polyurethane according to claim 6, characterized in that: The mass ratio of perfluorooctanoyl chloride, hydroxylated benzoxazine and triethylamine catalyst in S2 is 1.2-1.5:1:0.02-0.

03.

9. A method for preparing a water-based paint containing modified polyurethane according to any one of claims 1 to 8, characterized in that: The preparation method of the water-based paint containing modified polyurethane is as follows: adding modified polyurethane, silicon-containing benzoxazine, water-based acrylic resin, polyether-modified silicone defoamer, propylene glycol film-forming agent and water into a stirrer, stirring for 10-20 minutes, and obtaining the water-based paint containing modified polyurethane after stirring.

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