Preparation process of hydrophilic modified castor oil and application in water-based polyurethane mortar floor paint

Abstract

This invention belongs to the field of synthetic bio-based waterborne polyols, mainly applied to waterborne polyurethane mortar floor coatings. This invention provides a modified castor oil specifically for waterborne polyurethane mortar floor coatings. It achieves waterborne conversion and controllable functionality of castor oil through relatively simple process conditions. Emulsions made from the modified castor oil synthesized by this invention have better storage stability than emulsions made by direct external emulsification of castor oil. Furthermore, it requires less stringent process conditions than chemical grafting of functional groups to improve the hydrophilicity of castor oil, meaning that waterborne conversion and functionality control of castor oil can be achieved under milder conditions.

Description

Technical Field

[0001] This invention belongs to the field of synthetic bio-based waterborne polyols and is mainly applied to waterborne polyurethane mortar floor coatings. Background Technology

[0002] Castor oil has a long history of use in the polyurethane industry due to its excellent performance, low price, and good biodegradability. In the field of waterborne polyurethane mortar floor coatings, the longer aliphatic chain segments and lower reactivity of castor oil give waterborne polyurethane mortar flooring good water resistance, toughness, and low-temperature resistance.

[0003] However, current waterborne castor oil technology still has significant drawbacks, such as poor external emulsification stability and complex internal emulsification processes, which limit the application of castor oil in the field of waterborne polyurethane mortar floor coatings. Summary of the Invention

[0004] This invention provides a modified castor oil specifically for waterborne polyurethane mortar floor coatings. It achieves water-based castor oil and controllable functionality through relatively simple process conditions. The emulsion made from the modified castor oil synthesized by this invention has better storage stability than the emulsion made by direct external emulsification of castor oil. It also has lower process requirements than the chemical method of grafting functional groups to improve the hydrophilicity of castor oil, that is, water-based castor oil and functionality control can be achieved under milder conditions.

[0005] One objective of this invention is to provide a process for preparing hydrophilic modified castor oil, characterized by the following steps:

[0006] Step 1:

[0007] Weigh out an aqueous solution of sodium hydroxide and add it to a three-necked flask. Stir at low speed and heat to 80-100℃. Add 100g of dibenzoic acid diol ester dropwise over 10 minutes. Maintain the temperature under reflux and stir at low speed for 1.5-2.5 hours. After the reaction is complete, product 1 is obtained. The reaction equation is as follows:

[0008]

[0009] Step Two:

[0010] Weigh out refined castor oil and sodium hydroxide aqueous solution and add them to a three-necked flask. Maintain the temperature at 70-100℃ under reflux.

[0011] Stir at low speed for 1-3 hours. After the reaction is complete, product 2 is obtained. The reaction equation is as follows:

[0012]

[0013] Step 3:

[0014] Products 1 and 2, along with polyaspartic acid, were added to a three-necked flask and stirred for 2-4 hours under reflux at 90-120°C. The theoretical hydroxyl value and theoretical acid value were tested online. When the theoretical acid value was less than 2 mg KOH / g, the target modified castor oil was obtained. The reaction equation is as follows:

[0015]

[0016] Preferably, the dibenzoic acid diol ester mentioned in step one is at least one or a mixture of two of dipropylene glycol dibenzoate and diethylene glycol dibenzoate, and the amount used is 20-50% of the mass of refined castor oil.

[0017] Preferably, the amount of dibenzoic acid diol ester used in step one is 30-40% of the mass of refined castor oil;

[0018] Preferably, the concentration of the sodium hydroxide aqueous solution in step one is 50-80%, and the amount used is 20-40% of the mass of the dibenzoic acid diol ester;

[0019] Preferably, the concentration of the sodium hydroxide aqueous solution in step one is 69-75%, and the amount used is 30-35% of the mass of the dibenzoic acid diol ester;

[0020] Preferably, the concentration of the sodium hydroxide aqueous solution in step two is 60-85%, and the amount used is 5-10% of the mass of refined castor oil;

[0021] Preferably, the concentration of the sodium hydroxide aqueous solution in step two is 69-80%, and the amount used is 5.5-6.5% of the mass of refined castor oil;

[0022] Preferably, the polyaspartic acid used in step three is polyaspartic acid with a molecular weight in the range of 3000-5000, and the amount of polyaspartic acid used is 5-15% of the mass of refined castor oil.

[0023] Preferably, in step three, the amount of polyaspartic acid used is 10-13% of the mass of refined castor oil.

[0024] Preferably, the formula for calculating the theoretical hydroxyl value in step three is as follows:

[0025] (1) HV = 56100*n ―OH / m 总

[0026] (2)m 总 =m 精制蓖麻油 +m 二苯甲酸二二元醇型酯 +m 氢氧化钠 +m 聚天门冬氨酸 +m 水

[0027] (3)

[0028] (4) m——mass, n——amount of substance, Q——equivalent, M——molecular weight, HV——hydroxyl value.

[0029] The second objective of this invention is to provide a modified castor oil prepared by the above-mentioned hydrophilic modified castor oil preparation process.

[0030] The third objective of this invention is to provide a hydrophilic modified castor oil and its application in waterborne polyurethane mortar floor coatings. The waterborne polyurethane mortar floor coating consists of four components: A, B, C, and D. Component A is a polyol emulsion made from modified castor oil, component B is a modified isocyanate, component C is a filler, and component D is a color paste.

[0031] This invention utilizes saponified ester plasticizers to generate diols, thereby increasing the curing and crosslinking density of modified castor oil and isocyanate. It also utilizes the incomplete saponification of refined castor oil to generate aliphatic sodium salts containing hydroxyl groups, as well as glycerol diricinoleate and monolinoleate. Finally, it uses polyaspartic acid to recombine and crosslink the aforementioned hydroxyl-containing compounds through esterification. Different functionalities of the modified castor oil are achieved through polyaspartic acid with different molecular weights. Simultaneously, the grafted aliphatic sodium salts provide good hydrophilicity to the modified castor oil molecules, and the hindered amino groups in the polyaspartic acid can react with isocyanate to form urea bonds, significantly improving the temperature resistance and chemical resistance of the coating film. Detailed Implementation

[0032] Example 1

[0033] Step 1: Weigh 33.9g of 69% sodium hydroxide aqueous solution and add it to a three-necked flask. Stir at low speed and heat to 80°C. Add 100g of diethylene glycol dibenzoate dropwise over 10 minutes. Keep the temperature at 80°C under reflux and stir at low speed for 2.5 hours. After the reaction is complete, product 1 is obtained.

[0034] Step 2: Weigh 100g of refined castor oil and 6.2g of 69% sodium hydroxide aqueous solution and add them to a three-necked flask. Maintain the temperature at 80℃ under reflux and stir at low speed for 1.5h. After the reaction is completed, product 2 is obtained.

[0035] Step 3: Weigh 20g of product 1, 100g of product 2, and 4g of polyaspartic acid (Mn=3000), add them to a three-necked flask, reflux at 90℃ for 4 hours, test the hydroxyl value to be 108mgKOH / g and the acid value to be 1.3mgKOH / g, and obtain modified castor oil 1.

[0036] Example 2

[0037] Step 1: Weigh 42g of 75% sodium hydroxide aqueous solution and add it to a three-necked flask. Stir at low speed and heat to 80°C. Add 100g of diethylene glycol dibenzoate dropwise over 10 minutes. Keep the temperature at 80°C under reflux and stir at low speed for 2.5 hours. After the reaction is complete, product 1 is obtained.

[0038] Step 2: Weigh 100g of refined castor oil and 9.5g of 80% sodium hydroxide aqueous solution and add them to a three-necked flask. Maintain the temperature at 80℃ under reflux and stir at low speed for 1.5h. After the reaction is completed, product 2 is obtained.

[0039] Step 3: Weigh 20g of product 1, 100g of product 2, and 4g of polyaspartic acid (Mn=3000), add them to a three-necked flask, reflux at 90℃ for 4 hours, test the hydroxyl value to be 98mgKOH / g and the acid value to be 1.0mgKOH / g, and the modified castor oil 2 is obtained.

[0040] Example 3

[0041] Step 1: Weigh 33.9g of 69% sodium hydroxide aqueous solution and add it to a three-necked flask. Stir at low speed and heat to 100℃. Add 100g of diethylene glycol dibenzoate dropwise within 10min. Keep the temperature at 80℃ under reflux and stir at low speed for 2.5h. After the reaction is completed, product 1 is obtained.

[0042] Step 2: Weigh 100g of refined castor oil and 6.2g of 69% sodium hydroxide aqueous solution and add them to a three-necked flask. Maintain the temperature at 70℃ under reflux and stir at low speed for 1.5h. After the reaction is completed, product 2 is obtained.

[0043] Step 3: Weigh 20g of product 1, 100g of product 2, and 4g of polyaspartic acid (Mn=3000), add them to a three-necked flask, reflux at 120℃ for 4h, test the hydroxyl value to be 118mgKOH / g and the acid value to be 1.1mgKOH / g, and obtain modified castor oil 3.

[0044] Example 4

[0045] Step 1: Weigh 33.9g of 69% sodium hydroxide aqueous solution and add it to a three-necked flask. Stir at low speed and heat to 100℃. Add 100g of diethylene glycol dibenzoate dropwise within 10min. Keep the temperature at 80℃ under reflux and stir at low speed for 2.5h. After the reaction is completed, product 1 is obtained.

[0046] Step 2: Weigh 100g of refined castor oil and 6.2g of 69% sodium hydroxide aqueous solution and add them to a three-necked flask. Maintain the temperature at 70℃ under reflux and stir at low speed for 1.5h. After the reaction is completed, product 2 is obtained.

[0047] Step 3: Weigh 40g of product 1, 100g of product 2, and 4g of polyaspartic acid (Mn=3000), add them to a three-necked flask, reflux at 120℃ for 4h, test the hydroxyl value to be 112mgKOH / g and the acid value to be 1.1mgKOH / g, and obtain modified castor oil 4.

[0048] Example 5

[0049] Step 1: Weigh 33.9g of 69% sodium hydroxide aqueous solution and add it to a three-necked flask. Stir at low speed and heat to 100℃. Add 100g of diethylene glycol dibenzoate dropwise within 10min. Keep the temperature at 80℃ under reflux and stir at low speed for 2.5h. After the reaction is completed, product 1 is obtained.

[0050] Step 2: Weigh 100g of refined castor oil and 6.2g of 69% sodium hydroxide aqueous solution and add them to a three-necked flask. Maintain the temperature at 70℃ under reflux and stir at low speed for 1.5h. After the reaction is completed, product 2 is obtained.

[0051] Step 3: Weigh 40g of product 1, 100g of product 2, and 4g of polyaspartic acid (Mn=5000), add them to a three-necked flask, reflux at 120℃ for 4 hours, test the hydroxyl value to be 100mgKOH / g and the acid value to be 1.4mgKOH / g, and obtain modified castor oil 5.

[0052] Application Examples 1-6: Application Examples 1-5 represent different modified castor oils under different synthesis processes. Different modified castor oils have different physicochemical properties, so the A component of the waterborne polyurethane mortar in each application example is also different, and the physicochemical properties of the final waterborne polyurethane mortar film are also different, which can be adapted to different systems. Application Example 6 is a comparative example of the prior art.

[0053] Prepare polyol emulsions and other water-based polyurethane mortar components according to the following formula and process:

[0054]

[0055]

[0056] Note: The modified castor oil types in Application Examples 1-5 correspond to Modified Castor Oil 1-5 respectively.

[0057] Application Example 7:

[0058] According to the water-based polyurethane mortar mixing ratio in the table above, prepare water-based polyurethane mortar floor coating samples according to the following procedure:

[0059] The polyol emulsion, curing agent, and color paste are stirred at high speed for 1 minute to obtain a mixture. The mixture is then stirred at high speed with filler for 2-3 minutes to obtain water-based polyurethane mortar.

[0060] Sample preparation and testing were conducted according to the basic performance index requirements of polymer cement mortar in GB / T 22374-2018 standard, and the results are summarized below (test conditions: 23±2℃, 50±5%):

[0061]

[0062] In summary, compared with direct emulsification of castor oil, polyol emulsions made from modified castor oil have better stability. When applied to waterborne polyurethane mortar floor coatings, their performance can be adjusted within a certain range by changing the synthesis route of the modified castor oil.

Claims

1. A preparation process for hydrophilic modified castor oil, characterized in that... Includes the following steps: Step 1: Weigh out an aqueous solution of sodium hydroxide and add it to a three-necked flask. Stir at low speed and heat to 80-100℃. Add 100g of dibenzoic acid diol ester dropwise over 10 minutes. Maintain the temperature under reflux and stir at low speed for 1.5-2.5 hours. After the reaction is complete, product 1 is obtained. The reaction equation is as follows: ； Step Two: Weigh out refined castor oil and sodium hydroxide aqueous solution and add them to a three-necked flask. Maintain the temperature at 70-100℃ under reflux and stir at low speed for 1-3 hours. After the reaction is completed, product 2 is obtained. Step 3: Product 1, Product 2 and polyaspartic acid were added to a three-necked flask and stirred for 2-4 hours under reflux and condensation conditions at 90-120℃. The theoretical hydroxyl value and theoretical acid value were tested online. When the theoretical acid value was less than 2 mg KOH / g, the target modified castor oil was obtained. The amount of the dibenzoic acid diol ester used is 20-50% of the mass of refined castor oil; The polyaspartic acid used in step three is selected from polyaspartic acid with a molecular weight in the range of 3000-5000, and the amount of polyaspartic acid used in step three is 10-13% of the mass of refined castor oil; The formula for calculating the theoretical hydroxyl value mentioned in step three is as follows: ； (4) m —mass, n—amount of substance, Q—equivalent, M—molecular weight, HV—hydroxyl value.

2. The preparation process of hydrophilic modified castor oil according to claim 1, characterized in that... The amount of the dibenzoic acid diol ester used is 30-40% of the mass of refined castor oil.

3. The preparation process of hydrophilic modified castor oil according to claim 1, characterized in that... The sodium hydroxide aqueous solution in step one has a concentration of 50-80% and is used in an amount of 20-40% of the mass of dibenzoic acid diol ester.

4. The preparation process of hydrophilic modified castor oil according to claim 3, characterized in that... The sodium hydroxide aqueous solution in step one has a concentration of 69-75% and is used in an amount of 30-35% of the mass of dibenzoic acid diol ester.

5. The preparation process of hydrophilic modified castor oil according to claim 1, characterized in that... The sodium hydroxide aqueous solution used in step two has a concentration of 60-85% and is used in an amount of 5-10% of the mass of refined castor oil.

6. The preparation process of hydrophilic modified castor oil according to claim 5, characterized in that... The sodium hydroxide aqueous solution in step two has a concentration of 69-80% and is used in an amount of 5.5-6.5% of the mass of refined castor oil.

7. Modified castor oil prepared by the preparation process of hydrophilic modified castor oil according to any one of claims 1-6.

8. The application of the modified castor oil according to claim 7 in the processing of waterborne polyurethane mortar floor coatings.

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