An aqueous polyurethane emulsion and its preparation method

Abstract

The present application provides an aqueous polyurethane emulsion and a preparation method thereof. The preparation method includes: mixing a heated polyester polyol, a partial neutralizing agent, a first chain extender, and a catalyst to obtain mixture 1; mixing sodium silicate with mixture 1 to obtain mixture 2, and heating mixture 2 to 60°C to 80°C; adding a second chain extender and the remaining neutralizing agent to mixture 2 to obtain mixture 3; adding water to mixture 3 for emulsification to obtain the aqueous polyurethane emulsion. The aqueous polyurethane emulsion provided by the present application has a paint film with excellent mechanical properties and can prevent the continuous combustion of the flame into the polymer interior, and the film layer has flame retardant properties.

Description

Technical Field

[0001] This application relates to, but is not limited to, the fields of waterborne resins and waterborne coatings, and particularly relates to, but is not limited to, a flame-retardant waterborne polyurethane emulsion and a preparation method thereof. Background Art

[0002] With the increasing attention of humans to the environment and health, waterborne coatings have been increasingly widely used. Among them, waterborne two-component polyurethane coatings are a popular direction in the development of waterborne coatings. However, waterborne two-component polyurethane coatings still cannot meet the social needs in some properties, such as poor mechanical properties of the coating film, low hardness, and poor stability. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail in this application. This overview is not intended to limit the scope of protection of the claims.

[0004] This application provides a preparation method of a waterborne polyurethane emulsion, including:

[0005] Mixing the heated polyester polyol, partial neutralizing agent, first chain extender, and catalyst to obtain mixture 1;

[0006] Mixing sodium silicate with the mixture 1 to obtain mixture 2, and heating the mixture 2 to 60°C to 80°C;

[0007] Adding a second chain extender and the remaining neutralizing agent to the mixture 2 to obtain mixture 3;

[0008] Adding water to the mixture 3 for emulsification to obtain the waterborne polyurethane emulsion.

[0009] In an embodiment provided by this application, the polyester polyol is heated to 50°C to 70°C.

[0010] In an embodiment provided by this application, the partial neutralizing agent and the first chain extender are mixed evenly and then added dropwise into the polyester polyol for reaction for 30 min to 50 min.

[0011] In an embodiment provided by this application, the catalyst is added to the mixture of the polyester polyol, the neutralizing agent, and the first chain extender.

[0012] In an embodiment provided by this application, the viscosity of the mixture 2 is 100 mPa·s to 500 mPa·s.

[0013] In an embodiment provided by this application, a viscosity regulator is used to adjust the viscosity of the mixture 2.

[0014] In an embodiment provided by the present application, the viscosity regulator is selected from any one or more of acetone, methyl ethyl ketone, N,N-dimethylformamide, and dioxane.

[0015] In an embodiment provided by the present application, the sodium silicate is added to the mixture 1 and stirred. The stirring speed is 800 r / min to 1000 r / min, and the stirring time is 6 h to 8 h.

[0016] In an embodiment provided by the present application, the second chain extender is added to the mixture 2 first, and then the remaining salt-forming agent is added.

[0017] In an embodiment provided by the present application, the second chain extender is added to the mixture 2 first, and then stirred at a speed of 800 r / min to 1000 r / min for 30 min to 50 min, and then the remaining salt-forming agent is added.

[0018] In an embodiment provided by the present application, the water addition and emulsification include stirring. The stirring speed is 500 r / min to 700 r / min, and the stirring time is 30 min to 50 min.

[0019] In an embodiment provided by the present application, after the water addition and emulsification, the viscosity regulator is removed by reduced pressure distillation.

[0020] In an embodiment provided by the present application, the polyester polyol is selected from any one or more of polycaprolactone diol and polybutylene adipate.

[0021] In an embodiment provided by the present application, the salt-forming agent is selected from any one or more of sodium hydroxide, triethylamine, dimethylethanolamine, and ammonia water.

[0022] In an embodiment provided by the present application, the first chain extender is selected from any one or more of sodium 3-sulfolactate, diethylene glycol, 4,4'-dihydroxydiphenylpropane, trimethylolpropane, and 2,2-bis(hydroxymethyl)propionic acid.

[0023] In an embodiment provided by the present application, the catalyst is selected from any one or more of dibutyltin dilaurate, dibutyltin diacetate, and stannous octanoate.

[0024] In an embodiment provided by the present application, the modulus of the sodium silicate is 0.2 to 1.

[0025] In an embodiment provided by the present application, the second chain extender is selected from any one or more of 1,4-butanediol, ethylene glycol, diethylene glycol, ethylenediamine, diethylenetriamine, and triethylenetetramine.

[0026] In an embodiment provided by the present application, the polyester polyol is dried before use. In an embodiment provided by the present application, the drying treatment of the polyester polyol includes vacuum drying at 60°C to 80°C for 10 h to 12 h.

[0027] In an embodiment provided by the present application, the sodium silicate is dried before use. In an embodiment provided by the present application, the drying treatment of the sodium silicate includes vacuum drying at 60°C to 80°C for 10 h to 12 h.

[0028] In an embodiment provided by the present application, the amounts of raw materials in the preparation method are calculated by weight and include 30 to 50 parts of sodium silicate, 15 to 25 parts of polyester polyol, 5 to 15 parts of the first chain extender, 15 to 25 parts of the second chain extender, 1 to 5 parts of a salt-forming agent, 0 to 0.5 parts of a catalyst, 5 parts to 10 parts of a viscosity modifier, and 0 parts to 15 parts of water.

[0029] On the other hand, the present application provides an aqueous polyurethane emulsion prepared by using the above preparation method.

[0030] In an embodiment provided by the present application, the aqueous polyurethane emulsion forms a two-component system with a curing agent and is mixed with the curing agent during use.

[0031] In an embodiment provided by the present application, the curing agent is selected from isocyanate curing agents.

[0032] The aqueous polyurethane emulsion provided by the present application has a film with excellent mechanical properties and can prevent the continuous combustion of the flame into the polymer interior, and the film layer has flame retardant properties.

[0033] Other features and advantages of the present application will be described in the subsequent description, and some of them will be obvious from the description or understood by implementing the present application. Other advantages of the present application can be achieved and obtained through the solutions described in the description. Detailed Embodiments

[0034] To make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be described in detail below. It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily.

[0035] Example 1

[0036] 50 parts of sodium silicate with a modulus of 0.8, 15 parts of polybutylene adipate HY-600 (Xuzhou Yihuiyang New Materials Co., Ltd.), 10 parts of diethylene glycol (Xuzhou Yihuiyang New Materials Co., Ltd.), 15 parts of ethylene glycol (Xuzhou Yihuiyang New Materials Co., Ltd.), 2 parts of sodium hydroxide (Cangzhou Yayi Jin Chemical Products Co., Ltd.), 0.5 part of dibutyltin dilaurate (Nanjing Quanxi Chemical Co., Ltd.), 5 parts of 1,4-dioxane and 2.5 parts of water.

[0037] Preparation method:

[0038] Step a, vacuum dry the polyester polyol and sodium silicate at 60 °C for 12 h;

[0039] Step b, add the polyester polyol to the reaction kettle and heat up to 60 °C;

[0040] Step c, mix part of the salt-forming agent in the first chain extender and dropwise add it to the reaction kettle, and react for 30 min;

[0041] Step d, add the catalyst to the reaction kettle to promote the reaction to obtain mixture 1;

[0042] Step e, after adding sodium silicate, heat up to 70 °C and continue stirring at 800 r / min for 6 h. During the reaction, pay attention to controlling the viscosity of the system with a viscosity regulator to not more than 500 mPa·s to obtain mixture 2;

[0043] Step f, after the system cools down to room temperature, add the second chain extender and continue stirring at 800 r / min for 30 min, then add the remaining salt-forming agent and quickly stir to neutralize the system to obtain mixture 3;

[0044] Step g, add deionized water and quickly stir and emulsify at 500 r / min to 700 r / min for 30 min;

[0045] Step h, remove the viscosity regulator by vacuum distillation to obtain the sodium silicate-modified waterborne two-component polyurethane emulsion.

[0046] Example 2

[0047] 36 parts of sodium silicate with a modulus of 0.8, 18 parts of polybutylene adipate HY-600 (Xuzhou Yihuiyang New Materials Co., Ltd.), 10 parts of diethylene glycol (Xuzhou Yihuiyang New Materials Co., Ltd.), 18 parts of ethylene glycol (Xuzhou Yihuiyang New Materials Co., Ltd.), 2 parts of sodium hydroxide (Cangzhou Yayi Jin Chemical Products Co., Ltd.), 0.5 part of dibutyltin dilaurate (Nanjing Quanxi Chemical Co., Ltd.), 5 parts of 1,4-dioxane and 10.5 parts of water.

[0048] Preparation method:

[0049] Step a: Vacuum dry the polyester polyol and sodium silicate at 60 °C for 12 h;

[0050] Step b: Add the polyester polyol into the reaction kettle and heat up to 60 °C;

[0051] Step c: Mix part of the salt-forming agent in the first chain extender and dropwise add it into the reaction kettle, and react for 30 min;

[0052] Step d: Add the catalyst into the reaction kettle to promote the reaction and obtain Mixture 1;

[0053] Step e: After adding sodium silicate, heat up to 70 °C and continue stirring at 800 r / min for 6 h. During the reaction, pay attention to controlling the viscosity of the system with a viscosity regulator to be no more than 500 mPa·s to obtain Mixture 2;

[0054] Step f: After the system cools down to room temperature, add the second chain extender and continue stirring at 800 r / min for 30 min. Then add the remaining salt-forming agent and quickly stir to neutralize the system to obtain Mixture 3;

[0055] Step g: Add deionized water and quickly stir and emulsify at 500 r / min to 700 r / min for 30 min;

[0056] Step h: Remove the viscosity regulator by vacuum distillation to prepare a sodium silicate-modified waterborne two-component polyurethane emulsion.

[0057] Example 3

[0058] 32 parts of sodium silicate with a modulus of 0.8, 18 parts of polybutylene adipate HY-600 (Xuzhou Yihuiyang New Materials Co., Ltd.), 15 parts of diethylene glycol (Xuzhou Yihuiyang New Materials Co., Ltd.), 20 parts of ethylene glycol (Xuzhou Yihuiyang New Materials Co., Ltd.), 2 parts of sodium hydroxide (Cangzhou Yayi Jin Chemical Products Co., Ltd.), 0.5 part of dibutyltin dilaurate (Nanjing Quanxi Chemical Co., Ltd.), 5 parts of 1,4-dioxane and 7.5 parts of water.

[0059] Preparation method:

[0060] Step a: Vacuum dry the polyester polyol and sodium silicate at 60 °C for 12 h;

[0061] Step b: Add the polyester polyol into the reaction kettle and heat up to 60 °C;

[0062] Step c: Mix part of the salt-forming agent in the first chain extender and dropwise add it into the reaction kettle, and react for 30 min; Step d: Add the catalyst into the reaction kettle to promote the reaction and obtain Mixture 1;

[0063] Step e: After adding sodium silicate, heat up to 70°C and continue stirring at 800 r / min for 6 h. During the reaction, pay attention to controlling the viscosity of the system with a viscosity regulator to no more than 500 mPa·s to obtain Mixture 2.

[0064] Step f: After the system cools down to room temperature, add the second chain extender and continue stirring at 800 r / min for 30 min. Then add the remaining salt-forming agent and quickly stir to neutralize the system to obtain Mixture 3.

[0065] Step g: Add deionized water and quickly stir and emulsify at 500 r / min to 700 r / min for 30 min.

[0066] Step h: Remove the viscosity regulator by vacuum distillation to prepare the sodium silicate-modified waterborne two-component polyurethane emulsion.

[0067] Comparative Example 1

[0068] A common waterborne two-component polyurethane emulsion of the DB3615 brand purchased from Double Bond Fine Chemicals. Compared with the emulsion prepared in the examples of this application, this emulsion does not involve sodium silicate modification.

[0069] Comparative Example 2

[0070] A common waterborne two-component polyurethane emulsion of the AH213 brand purchased from Qirun New Materials. Compared with the emulsion prepared in the examples of this application, this emulsion does not involve sodium silicate modification.

[0071] The sodium silicate-modified waterborne two-component polyurethane emulsion prepared in the examples of this application was subjected to application experiments with commercially available waterborne two-component polyurethane emulsion 1 and waterborne two-component polyurethane emulsion 2. The application scenarios are shown in Table 1 and the application effects are shown in Table 2.

[0072] Table 1

[0073]

[0074]

[0075] Table 2

[0076]

[0077]

[0078] 2. The coating film has flame retardant properties.

[0079] Using sodium silicate-modified polyurethane emulsion can improve the mechanical properties of the coating film and endow the coating film with flame retardant properties. According to the provisions of "GB 8624-2012 Classification of the Burning Behavior of Building Materials and Products", the flame retardant properties can reach Class B1 and above, and the best effect can reach non-combustible Class A2.

Claims

1. A preparation method of an aqueous polyurethane emulsion, characterized in that, comprising, mixing the heated polyester polyol, partial salt-forming agent, first chain extender and catalyst to obtain mixture 1; mixing sodium silicate with the mixture 1 to obtain mixture 2, and heating the mixture 2 to 60°C to 80°C; adding a second chain extender and the remaining salt-forming agent to the mixture 2 to obtain mixture 3; adding water to the mixture 3 for emulsification to obtain the aqueous polyurethane emulsion; the polyester polyol is selected from any one or more of polycaprolactone diol and butanediol adipate; the salt-forming agent is selected from any one or more of sodium hydroxide, triethylamine, dimethylethanolamine and ammonia water; the first chain extender is selected from any one or more of sodium 3-sulfo-1,2-dihydroxypropane, diethylene glycol, 4,4'-dihydroxydiphenyl propane, trimethylolpropane and 2,2-bis(hydroxymethyl)propionic acid; the catalyst is selected from any one or more of dibutyltin dilaurate, dibutyltin diacetate and stannous octoate; the second chain extender is selected from any one or more of 1,4-butanediol, ethylene glycol, diethylene glycol, ethylenediamine, diethylenetriamine and triethylenetetramine; the modulus of the sodium silicate is 0.2 to 1; the dosages of the raw materials in the preparation method include, by weight, 30 to 50 parts of sodium silicate, 15 to 25 parts of polyester polyol, 5 to 15 parts of the first chain extender, 15 to 25 parts of the second chain extender, 1 to 5 parts of salt-forming agent, 0 to 0.5 parts of catalyst, 5 parts to 10 parts of viscosity regulator and 0 parts to 15 parts of water.

2. The preparation method of the aqueous polyurethane emulsion according to claim 1, characterized in that, the polyester polyol is heated to 50°C to 70°C.

3. The preparation method of the aqueous polyurethane emulsion according to claim 1, characterized in that, the partial salt-forming agent and the first chain extender are mixed evenly and then dropped into the polyester polyol for reaction for 30 min to 50 min.

4. The preparation method of the aqueous polyurethane emulsion according to claim 3, characterized in that, the catalyst is added to the mixture of the polyester polyol, the salt-forming agent and the first chain extender.

5. The preparation method of the aqueous polyurethane emulsion according to claim 1, characterized in that, the viscosity of the mixture 2 is 100 mPa·s to 500 mPa·s.

6. The preparation method of the aqueous polyurethane emulsion according to claim 5, characterized in that, a viscosity regulator is used to adjust the viscosity of the mixture 2.

7. The preparation method of the aqueous polyurethane emulsion according to claim 6, characterized in that, the viscosity regulator is selected from any one or more of acetone, butanone, methyl ethyl ketone, N,N-dimethylformamide and dioxane.

8. The preparation method of the aqueous polyurethane emulsion according to claim 1, characterized in that, adding the sodium silicate to the mixture 1 and stirring, the stirring speed is 800 r / min to 1000 r / min, and the stirring time is 6 h to 8 h.

9. The preparation method of the aqueous polyurethane emulsion according to claim 1, characterized in that, The second chain extender is first added to the mixture 2, and then the remaining salt-forming agent is added.

10. The method for preparing the aqueous polyurethane emulsion according to claim 9, characterized in that the second chain extender is first added to the mixture 2, and then stirred at a rotation speed of 800 r / min to 1000 r / min for 30 min to 50 min, and then the remaining salt-forming agent is added.

11. The method for preparing the aqueous polyurethane emulsion according to claim 6 or 7, characterized in that the water addition emulsification includes stirring, the rotation speed of the stirring is 500 r / min to 700 r / min, and the stirring time is 30 min to 50 min.

12. The method for preparing the aqueous polyurethane emulsion according to claim 11, characterized in that after the water addition emulsification, the viscosity regulator is removed by vacuum evaporation.

13. The method for preparing the aqueous polyurethane emulsion according to any one of claims 1 to 10, characterized in that the polyester polyol is dried before use.

14. The method for preparing the aqueous polyurethane emulsion according to claim 13, characterized in that the drying treatment of the polyester polyol includes vacuum drying at 60 °C to 80 °C for 10 h to 12 h.

15. The method for preparing the aqueous polyurethane emulsion according to claim 13, characterized in that the sodium silicate is dried before use.

16. The method for preparing the aqueous polyurethane emulsion according to claim 15, characterized in that the drying treatment of the sodium silicate includes vacuum drying at 60 °C to 80 °C for 10 h to 12 h.

17. An aqueous polyurethane emulsion prepared by the preparation method according to any one of claims 1 to 16.

18. The aqueous polyurethane emulsion according to claim 17, characterized in that the aqueous polyurethane emulsion and the curing agent form a two-component system and are mixed with the curing agent during use.

19. The aqueous polyurethane emulsion according to claim 18, characterized in that the curing agent is selected from isocyanate curing agents.

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