Polyether polyols for use in the synthesis of aqueous polyurethane dispersions and methods of synthesis

Abstract

This invention discloses a polyether polyol for the synthesis of waterborne polyurethane dispersions and its synthesis method, relating to the field of fine chemicals. Using phenylene oxide, ethylene oxide, and propylene oxide as comonomers, water and glycerol as initiators, and potassium alkoxide as a catalyst, a polyethylene glycol containing benzene rings in its side chains is prepared. This polyether polyol, used in the synthesis of waterborne polyurethane dispersions, can replace a portion of the polyester polyol, achieving the same performance. Furthermore, the emulsion remains stable over a long period, exhibits significantly improved hydrolysis resistance, and demonstrates good adhesion.

Description

Technical Field

[0001] This invention relates to the field of fine chemicals, specifically to a polyether polyol for the synthesis of waterborne polyurethane dispersions and a synthesis method thereof. Background Technology

[0002] Currently, conventional polyether polyols are obtained through anionic polymerization using ethylene oxide and propylene oxide as monomers, and are typically distinguished by molecular weight, hydroxyl value, and functionality. Due to the inherent flexibility of polyethylene glycol segments, polyester polyols are usually added to provide strength during the synthesis of waterborne polyurethane dispersions. However, the ester bonds in polyester polyols are prone to hydrolysis during long-term storage, leading to a decline in emulsion performance or even demulsification. Summary of the Invention

[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a polyether polyol for the synthesis of aqueous polyurethane dispersions and a synthesis method thereof.

[0004] The technical solution of the present invention is as follows: A method for synthesizing polyether polyols for waterborne polyurethane dispersions, using phenylene oxide, ethylene oxide, and propylene oxide as comonomers, water and glycerol as initiators, and potassium alkoxide as catalysts, to prepare polyethylene glycol containing benzene rings in the side chains.

[0005] As a preferred embodiment of the present invention, the following steps are included: S1: Add potassium alkoxide to a mixed solution of glycerol and water, add phenylene oxide first, and polymerize at 70-100℃ for 1-2 hours; S2: Continue adding propylene oxide and polymerize at 70-100℃ for 1-2 hours; S3: Next, add ethylene oxide and polymerize at 70-100℃ for 0.5-2 hours; S4: Finally, treat with an adsorbent to obtain the product.

[0006] As a preferred embodiment of the present invention, the methoxide is sodium methoxide, and its addition amount accounts for 0.1-0.5% of the total mass of the comonomer.

[0007] As a preferred embodiment of the present invention, the mass ratio of phenylene oxide, propylene oxide and ethylene oxide is 3-5:2-4:1-4.

[0008] As a preferred embodiment of the present invention, the volume ratio of glycerol to water is 1:3-5.

[0009] As a preferred embodiment of the present invention, the adsorbent is prepared by the following method: Zeolite powder, activated carbon, nano silica and bentonite are mixed evenly and then added to an aqueous solution containing methyl glucoside ether and sodium hydroxymethyl cellulose.

[0010] As a preferred embodiment of the present invention, the mass ratio of the methyl glucoside ether and sodium hydroxymethyl cellulose is 1:6-10, and the total mass of the two accounts for 30-50% of the mass of water.

[0011] As a preferred embodiment of the present invention, the mass ratio of zeolite powder, activated carbon, nano silica and bentonite is 5-7:1-4:0.2-3:2-4.

[0012] The present invention also discloses a polyether polyol for the synthesis of aqueous polyurethane dispersions, which is obtained by any of the synthesis methods described above.

[0013] The present invention also discloses an aqueous polyurethane dispersion made from the above-mentioned polyether polyol.

[0014] The beneficial effects of this invention are as follows: This invention uses styrene oxide, ethylene oxide, and propylene oxide as comonomers, water and glycerol as initiators, and potassium alkoxide as a catalyst to prepare polyethylene glycol containing benzene rings in its side chains. The introduction of benzene rings reduces water molecule penetration, overcomes the easy hydrolysis defect of polyester, and greatly improves the hydrolysis resistance of the polyol; the benzene rings enhance the rigidity of the molecular chain, replacing the crystalline segments of the polyester; and the benzene rings have a high decomposition temperature and good thermal stability.

[0015] Simultaneously, the use of specific adsorbents improves the purity of the product and reduces the impact of residual monomers, catalysts, colored impurities, and low-molecular-weight odor components. The adsorbents utilize methyl glucoside ether and sodium carboxymethyl cellulose to modify the inorganic mixture. Methyl glucoside ether (methyl glucoside polyoxyethylene ether) can alter the surface properties of the inorganic mixture by interacting with the silicon-oxygen structure on its surface. The hydrophilic head of the methyl glucoside ether can form hydrogen bonds with the hydroxyl groups on the inorganic mixture surface, while the hydrophobic tail can insert into the pores of the inorganic mixture, thereby changing the pore size and surface charge of the zeolite. This modification enhances the adsorption capacity of the inorganic mixture for organic matter. Sodium carboxymethyl cellulose is a water-soluble cellulose derivative that can be combined with zeolite through physical or chemical methods. The long-chain structure of sodium carboxymethyl cellulose can coat the surface of the inorganic mixture, forming a protective film that prevents the hydrolysis of the silicon-oxygen structure on the surface of the inorganic mixture, thus maintaining its structural stability. Furthermore, nano-silica can improve the pore strength of the inorganic mixture.

[0016] This polyether polyol is used in the synthesis of aqueous polyurethane dispersions and can replace the polyester polyol portion to achieve the same performance. Detailed Implementation

[0017] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0018] Example 1 A method for synthesizing polyether polyols for use in the synthesis of aqueous polyurethane dispersions includes the following steps: S1: Add potassium alkoxide to a mixed solution of glycerol and water, add phenylene oxide first, and polymerize at 80°C for 2 hours; S2: Continue adding propylene oxide and polymerize at 80°C for 1 hour; S3: Next, add ethylene oxide and polymerize at 80°C for 1 hour; S4: Finally, treat with an adsorbent to obtain the product.

[0019] The methoxide is sodium methoxide, and its addition amount accounts for 0.1% of the total mass of the comonomer.

[0020] The mass ratio of phenylene oxide, propylene oxide, and ethylene oxide is 4:2:3.

[0021] The volume ratio of glycerol to water is 1:4.

[0022] The adsorbent is prepared as follows: Mix zeolite powder, activated carbon, nano silica and bentonite evenly, and then soak them in an aqueous solution containing methyl glucoside ether and sodium hydroxymethyl cellulose for 30 minutes.

[0023] The mass ratio of the methyl glucoside ether and sodium hydroxymethyl cellulose is 1:7, and the total mass of the two accounts for 30% of the mass of water.

[0024] The mass ratio of the zeolite powder, activated carbon, nano-silica, and bentonite is 6:1:0.2:2.

[0025] Example 2 A method for synthesizing polyether polyols for use in the synthesis of aqueous polyurethane dispersions includes the following steps: S1: Add potassium alkoxide to a mixed solution of glycerol and water, add phenylene oxide first, and polymerize at 80°C for 1 hour; S2: Continue adding propylene oxide and polymerize at 80°C for 1 hour; S3: Next, add ethylene oxide and polymerize at 80°C for 1 hour; S4: Finally, treat with an adsorbent to obtain the product.

[0026] The methoxide is sodium methoxide, and its addition amount accounts for 0.1% of the total mass of the comonomer.

[0027] The mass ratio of phenylene oxide, propylene oxide, and ethylene oxide is 4:2:1.

[0028] The volume ratio of glycerol to water is 1:4.

[0029] The adsorbent is prepared as follows: Mix zeolite powder, activated carbon, nano silica and bentonite evenly, and then soak them in an aqueous solution containing methyl glucoside ether and sodium hydroxymethyl cellulose for 30 minutes.

[0030] The mass ratio of the methyl glucoside ether and sodium hydroxymethyl cellulose is 1:7, and the total mass of the two accounts for 30% of the mass of water.

[0031] The mass ratio of the zeolite powder, activated carbon, nano-silica, and bentonite is 6:3:1:2.

[0032] Example 3 A method for synthesizing polyether polyols for use in the synthesis of aqueous polyurethane dispersions includes the following steps: S1: Add potassium alkoxide to a mixed solution of glycerol and water, add phenylene oxide first, and polymerize at 80°C for 1 hour; S2: Continue adding propylene oxide and polymerize at 80°C for 1 hour; S3: Next, add ethylene oxide and polymerize at 80°C for 1 hour; S4: Finally, treat with an adsorbent to obtain the product.

[0033] The methoxide is sodium methoxide, and its addition amount accounts for 0.1% of the total mass of the comonomer.

[0034] The mass ratio of phenylene oxide, propylene oxide, and ethylene oxide is 4:3:3.

[0035] The volume ratio of glycerol to water is 1:4.

[0036] The adsorbent is prepared as follows: Mix zeolite powder, activated carbon, nano silica and bentonite evenly, and then soak them in an aqueous solution containing methyl glucoside ether and sodium hydroxymethyl cellulose for 30 minutes.

[0037] The mass ratio of the methyl glucoside ether and sodium hydroxymethyl cellulose is 1:6, and the total mass of the two accounts for 40% of the mass of water.

[0038] The mass ratio of the zeolite powder, activated carbon, nano-silica, and bentonite is 5:2:0.8:2.

[0039] Example 4 A method for synthesizing polyether polyols for use in the synthesis of aqueous polyurethane dispersions includes the following steps: S1: Add potassium alkoxide to a mixed solution of glycerol and water, add phenylene oxide first, and polymerize at 80°C for 2 hours; S2: Continue adding propylene oxide and polymerize at 80°C for 1 hour; S3: Next, add ethylene oxide and polymerize at 80°C for 1 hour; S4: Finally, treat with an adsorbent to obtain the product.

[0040] The methoxide is sodium methoxide, and its addition amount accounts for 0.1% of the total mass of the comonomer.

[0041] The mass ratio of phenylene oxide, propylene oxide, and ethylene oxide is 4:3:3.

[0042] The volume ratio of glycerol to water is 1:4.

[0043] The adsorbent is prepared as follows: Mix zeolite powder, activated carbon, nano silica and bentonite evenly, and then soak them in an aqueous solution containing methyl glucoside ether and sodium hydroxymethyl cellulose for 30 minutes.

[0044] The mass ratio of the methyl glucoside ether to sodium hydroxymethyl cellulose is 1:7, and the total mass of the two accounts for 40% of the mass of water.

[0045] The mass ratio of the zeolite powder, activated carbon, nano-silica, and bentonite is 6:3:0.7:4.

[0046] Example 5 A method for synthesizing polyether polyols for use in the synthesis of aqueous polyurethane dispersions includes the following steps: S1: Add potassium alkoxide to a mixed solution of glycerol and water, add phenylene oxide first, and polymerize at 80°C for 2 hours; S2: Continue adding propylene oxide and polymerize at 80°C for 1 hour; S3: Next, add ethylene oxide and polymerize at 80°C for 1 hour; S4: Finally, treat with an adsorbent to obtain the product.

[0047] The methoxide is sodium methoxide, and its addition amount accounts for 0.1% of the total mass of the comonomer.

[0048] The mass ratio of phenylene oxide, propylene oxide, and ethylene oxide is 4:3:2.

[0049] The volume ratio of glycerol to water is 1:5.

[0050] The adsorbent is prepared as follows: Mix zeolite powder, activated carbon, nano silica and bentonite evenly, and then soak them in an aqueous solution containing methyl glucoside ether and sodium hydroxymethyl cellulose for 30 minutes.

[0051] The mass ratio of the methyl glucoside ether and sodium hydroxymethyl cellulose is 1:8, and the total mass of the two accounts for 50% of the mass of water.

[0052] The mass ratio of the zeolite powder, activated carbon, nano-silica, and bentonite is 7:1:0.9:3.

[0053] Comparative Example 1 Unlike Example 1, the adsorbent is a mixture of zeolite powder, activated carbon, nano-silica and bentonite.

[0054] Comparative Example 2 Unlike Example 1, the adsorbent is prepared by the following method: Mix zeolite powder, activated carbon, nano silica and bentonite evenly, then soak in a solution containing methyl glucoside ether for 30 minutes.

[0055] The concentration of the methyl glucoside ether is 30%.

[0056] The mass ratio of the zeolite powder, activated carbon, nano-silica, and bentonite is 6:1:0.2:2.

[0057] Comparative Example 3 The adsorbent is prepared as follows: Mix zeolite powder, activated carbon, nano silica and bentonite evenly, and then soak them in an aqueous solution of sodium hydroxymethyl cellulose for 30 minutes.

[0058] The concentration of the sodium hydroxymethyl cellulose is 30%.

[0059] The performance of the above embodiments and comparative examples was tested, and the test results are shown in Table 1.

[0060] Stability: According to GB / T20623-2006, after being placed at a constant temperature of 50±2℃ for 30 days, no hard lumps, no flocculation, no obvious stratification or crust formation were observed.

[0061] Table 1

[0062] As can be seen from Table 1, the performance of the examples is better than that of the comparative examples. The main reason may be that the introduction of benzene rings can reduce water molecule penetration, overcome the defects of easy hydrolysis of polyester, and greatly improve the hydrolysis resistance of polyols; benzene rings enhance the rigidity of molecular chains and replace the crystalline segments of polyester; benzene rings have high decomposition temperature and good thermal stability. At the same time, the use of specific adsorbents improves the purity of the product and reduces the influence of residual monomers, catalysts, colored impurities and low molecular weight off-odor components.

[0063] Meanwhile, the polyether polyol obtained above was combined with isocyanate to form an aqueous polyurethane dispersion, which has low viscosity at 25°C, excellent stability, and strong adhesion.

[0064] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of the present invention.

Claims

1. A method for synthesizing polyether polyols for the synthesis of aqueous polyurethane dispersions, characterized in that, Polyethylene glycol containing benzene rings in its side chains was prepared by using phenylene oxide, ethylene oxide, and propylene oxide as comonomers, water and glycerol as initiators, and potassium alkoxide as a catalyst.

2. The method for synthesizing polyether polyols for aqueous polyurethane dispersions according to claim 1, characterized in that, Includes the following steps: S1: Add potassium alkoxide to a mixed solution of glycerol and water, add phenylene oxide first, and polymerize at 70-100℃ for 1-2 hours; S2: Continue adding propylene oxide and polymerize at 70-100℃ for 1-2 hours; S3: Next, add ethylene oxide and polymerize at 70-100℃ for 0.5-2 hours; S4: Finally, treat with an adsorbent to obtain the product.

3. The method for synthesizing polyether polyols for aqueous polyurethane dispersions according to claim 2, characterized in that, The methoxide is sodium methoxide, and its addition amount accounts for 0.1-0.5% of the total mass of the comonomer.

4. The method for synthesizing polyether polyols for aqueous polyurethane dispersions according to claim 2, characterized in that, The mass ratio of the phenylene oxide, propylene oxide, and ethylene oxide is 3-5:2-4:1-4.

5. The method for synthesizing polyether polyols for aqueous polyurethane dispersions according to claim 2, characterized in that, The volume ratio of glycerol to water is 1:3-5.

6. The method for synthesizing polyether polyols for aqueous polyurethane dispersions according to claim 2, characterized in that, The adsorbent is prepared as follows: Zeolite powder, activated carbon, nano silica and bentonite are mixed evenly and then added to an aqueous solution containing methyl glucoside ether and sodium hydroxymethyl cellulose.

7. The method for synthesizing polyether polyols for aqueous polyurethane dispersions according to claim 6, characterized in that, The mass ratio of the methyl glucoside ether and sodium hydroxymethyl cellulose is 1:6-10, and the total mass of the two accounts for 30-50% of the mass of water.

8. The method for synthesizing polyether polyols for aqueous polyurethane dispersions according to claim 6, characterized in that, The mass ratio of the zeolite powder, activated carbon, nano-silica, and bentonite is 5-7:1-4:0.2-3:2-4.

9. A polyether polyol for the synthesis of aqueous polyurethane dispersions, characterized in that, It is obtained by the synthesis method described in any one of claims 1-8.

10. An aqueous polyurethane dispersion, characterized in that, It is made using the polyether polyol described in claim 9.

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