A preparation process and application of hyperbranched polyester polyol

Abstract

The present invention discloses a preparation process and application of hyperbranched polyester polyol. In the present invention, trimethylolpropane is used as the core, and a novel sodium sulfonate-based AB2 monomer is used as the branching monomer. Through self-polymerization reaction, a hyperbranched polyester polyol with a sodium sulfonate group in the main chain and a hydroxyl group at the end is obtained. Using it as a chain extender for polyurethane, a chain extension and cross-linking reaction are carried out with a terminal isocyanate polyurethane prepolymer formed by reacting with a polyol compound and a diisocyanate compound. The obtained hyperbranched waterborne polyurethane has the advantages of strong emulsion stability and long storage time. Moreover, the waterborne polyurethane has high water resistance. At the same time, it has better tensile properties, flexural strength and Shore A hardness.

Description

Technical Field

[0001] The invention relates to the technical field of hyperbranched polymers, in particular to a preparation process and application of a hyperbranched polyester polyol. Background Art

[0002] Hyperbranched polymers are polymers with three-dimensional dendritic structures, and their ends contain a large number of active functional groups. They are widely used in polymer materials such as polyurethane, polypropylene, and polystyrene, and can improve the impact resistance, processing performance, mechanical strength and other properties of the materials. The development of functional hyperbranched polymers is a hot research field. Polyurethane is a polymer material with excellent comprehensive performance, and is widely used in the fields of textiles, construction utilization, biomedicine, etc. Among them, water-based polyurethane uses water as a solvent, which is non-toxic and environmentally friendly, and has good practical applications in the fields of coatings, inks, adhesives, etc. However, water-based polyurethane has problems such as high water absorption, poor water resistance, and low mechanical strength. Modifying polyurethane with hyperbranched polymers can improve its mechanical properties. Patent CN108752563B discloses a water-based hyperbranched structure-modified polyurethane polymer and its preparation method, and a self-repairing diffuse reflection coating composition. In the preparation of polyurethane, sulfonate hydrophilic chain extenders, terminal hydroxyl hyperbranched polymers and other substances are added, and the obtained polyurethane coating composition has self-repairing and diffuse reflection properties, and has good hardness and flexibility. However, the polyurethane requires the additional addition of a water-based chain extender, and the patent does not improve the water resistance of the water-based polyurethane. Summary of the invention

[0003] The invention provides a hyperbranched polyester polyol, which solves the problems of poor stability and poor mechanical properties of polyurethane emulsion.

[0004] The technical scheme of the present invention is: a preparation process of a hyperbranched polyester polyol: N, N-dimethylformamide, trimethylolpropane, sodium sulfonate-based AB2 monomer and p-toluenesulfonic acid are added into a reaction bottle, nitrogen is introduced, the temperature is raised to 140-150°C, and the reaction is carried out for 6-8 hours; then the sodium sulfonate-based AB2 monomer and p-toluenesulfonic acid are added, the reaction is continued for 10-18 hours, low-boiling substances are removed by reduced pressure distillation, and drying is carried out to obtain a hyperbranched polyester polyol containing a sodium sulfonate group.

[0005] The structural formula of the sodium sulfonate-based AB2 monomer is formula (I):

[0006]

[0007] The molar ratio of trimethylolpropane, sodium sulfonate-based AB2 monomer, and p-toluenesulfonic acid is 1:(21-45):(0.08-0.18).

[0008] Wherein, the preparation process of sodium sulfonate-based AB2 monomer is:

[0009] (1) Add methanol, 3,5-diaminobenzoic acid, and 5-hydroxyvaleraldehyde to a reaction flask, heat to 35-45° C., react for 2-5 hours, then cool to room temperature, add sodium borohydride, wherein the molar ratio of 3,5-diaminobenzoic acid, 5-hydroxyvaleraldehyde, and sodium borohydride is 1:(2.1-2.4):(2-2.2), react for 10-15 hours, cool the reaction flask in an ice water bath, add dilute hydrochloric acid to adjust the pH of the solution to 4-5, stir to precipitate a precipitate, filter, wash with distilled water and petroleum ether in turn, and dry to obtain an AB2 precursor.

[0010] (2) Add methanol, ethanol or tetrahydrofuran solvent, AB2 precursor in a molar ratio of 1:(2.2-2.8):(2.2-2.8), sodium 2-bromoethane sulfonate, and triethylamine to a reaction flask, react at room temperature for 12-18 hours, concentrate under reduced pressure, wash with petroleum ether, and recrystallize the product in a 70% by volume ethanol aqueous solution to obtain a sodium sulfonate-based AB2 monomer.

[0011] Among them, the application of hyperbranched polyester polyol in hyperbranched waterborne polyurethane: add dried and dehydrated polyol compound and diisocyanate compound to the reaction bottle, introduce nitrogen, heat to 70-75°C, react for 2-3h, then reduce the temperature to 45-50°C, add acetone, add hyperbranched polyester polyol and dibutyltin dilaurate, react for 1-1.5h, add distilled water, concentrate under reduced pressure to remove acetone, add defoamer and leveling agent, shear and disperse, and obtain hyperbranched waterborne polyurethane.

[0012] The polyol compounds include polybutylene adipate diol, polycarbonate diol, and polycaprolactone diol; the diisocyanate compounds include isophorone diisocyanate, toluene-2,4-diisocyanate, and 4,4'-methylenebis(phenyl isocyanate).

[0013] The hyperbranched polyester polyol accounts for 5-18% of the total mass of the polyol compound and the diisocyanate compound.

[0014] The technical effect of the present invention is as follows: the trimethylolpropane of the present invention is used as a core, and the novel sodium sulfonate-based AB2 monomer is used as a branching monomer, and after a self-polymerization reaction, a hyperbranched polyester polyol containing a sodium sulfonate group in the main chain and a hydroxyl group at the end is obtained. The polyurethane is used as a chain extender for polyurethane, and a terminal isocyanate polyurethane prepolymer generated by reacting with a polyol compound and a diisocyanate compound is subjected to chain extension and crosslinking reaction to obtain a hyperbranched waterborne polyurethane. Thus, a large amount of sodium sulfonate hydrophilic groups are introduced into the polyurethane molecular chain, and no additional hydrophilic chain extender needs to be added, so that the water solubility of the hyperbranched waterborne polyurethane can be improved, the dispersibility in the water medium is good, the emulsion stability is strong, and the storage time is long.

[0015] The terminal position of the hyperbranched polyester polyol of the present invention contains a large number of hydroxyl groups, which undergo a cross-linking reaction with the terminal isocyanate polyurethane prepolymer to form a hyperbranched cross-linked network in the polyurethane, thereby increasing the cross-linking degree of the molecular chain of the polyurethane and forming a dense cross-linked network, which can inhibit water molecules from entering the interior of the polyurethane matrix, is conducive to reducing the water absorption rate, and improves the water resistance of the water-based polyurethane. At the same time, the polyurethane with the hyperbranched cross-linked network has better mechanical properties. The tensile strength reaches a maximum of 40.5MPa, the elongation at break reaches 680.1%, the bending strength reaches 85.5MPa, and the Shore A hardness reaches 87. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the reaction route for preparing sodium sulfonate-based AB2 monomers.

[0017] Figure 2 This is the reaction mechanism for the preparation of hyperbranched polyester polyols containing sodium sulfonate groups. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1

[0020] (1) Add 15 mL of methanol, 5 mmol of 3,5-diaminobenzoic acid, and 10.5 mmol of 5-hydroxypentanal to a reaction flask, heat to 45°C, react for 3 h, then cool to room temperature, add 11 mmol of sodium borohydride, react for 12 h, place the reaction flask in an ice water bath to cool, add dilute hydrochloric acid to adjust the pH of the solution to 4, stir to precipitate, filter, wash with distilled water and petroleum ether in turn, and dry to obtain AB2 precursor with a yield of 0.936 g as a white powder.

[0021] (2) Add 25 mL of methanol solvent, 5 mmol of AB2 precursor, 11 mmol of sodium 2-bromoethanesulfonate, and 11 mmol of triethylamine to a reaction flask, react at room temperature for 12 h, concentrate under reduced pressure, wash with petroleum ether, and recrystallize the product in a 70% by volume ethanol aqueous solution to obtain a sodium sulfonate-based AB2 monomer. The yield is 2.112 g, off-white powder.

[0022] Example 2

[0023] (1) Add 20 mL of methanol, 5 mmol of 3,5-diaminobenzoic acid, and 12 mmol of 5-hydroxypentanal to a reaction flask, heat to 45°C, react for 2 h, then cool to room temperature, add 10 mmol of sodium borohydride, react for 15 h, place the reaction flask in an ice-water bath to cool, add dilute hydrochloric acid to adjust the pH of the solution to 5, stir to precipitate, filter, wash with distilled water and petroleum ether in turn, and dry to obtain AB2 precursor with a yield of 0.871 g as a white powder.

[0024] (2) Add 30 mL of tetrahydrofuran solvent, 5 mmol of AB2 precursor, 14 mmol of sodium 2-bromoethane sulfonate, and 14 mmol of triethylamine to a reaction flask, react at room temperature for 12 h, concentrate under reduced pressure, wash with petroleum ether, and recrystallize the product in a 70% by volume ethanol aqueous solution to obtain a sodium sulfonate-based AB2 monomer. The yield is 1.867 g, off-white powder.

[0025] Example 3

[0026] (1) Add 20 mL of methanol, 5 mmol of 3,5-diaminobenzoic acid, and 11 mmol of 5-hydroxypentanal to a reaction flask, heat to 35°C, react for 5 h, then cool to room temperature, add 11 mmol of sodium borohydride, react for 10 h, cool the reaction flask in an ice water bath, add dilute hydrochloric acid to adjust the pH of the solution to 5, stir to precipitate, filter, wash with distilled water and petroleum ether in turn, and dry to obtain the AB2 precursor. Yield: 0.920 g, white powder.

[0027] (2) Add 20 mL of ethanol solvent, 5 mmol of AB2 precursor, 12 mmol of sodium 2-bromoethane sulfonate, and 12 mmol of triethylamine to a reaction flask, react at room temperature for 18 h, concentrate under reduced pressure, wash with petroleum ether, and recrystallize the product in a 70% by volume ethanol aqueous solution to obtain a sodium sulfonate-based AB2 monomer. The yield is 2.240 g, off-white powder.

[0028] Example 4

[0029] (1) Add 60 mL of N,N-dimethylformamide, 1 mmol of trimethylolpropane, 9 mmol of sodium sulfonate-based AB2 monomer (prepared by Example 3), and 0.035 mmol of p-toluenesulfonic acid into a reaction flask, introduce nitrogen, heat to 140° C., and react for 7 h; then add 12 mmol of sodium sulfonate-based AB2 monomer and 0.045 mmol of p-toluenesulfonic acid, continue to react for 10 h, remove low-boiling substances by distillation under reduced pressure, and dry to obtain a hyperbranched polyester polyol containing sodium sulfonate groups.

[0030] (2) Add 50 mmol (100 g) of dried and dehydrated polycarbonate diol 2000 and 120 mmol (20.9 g) of toluene-2,4-diisocyanate to a reaction flask, introduce nitrogen, heat to 70°C, react for 3 h, then lower the temperature to 45°C, add 50 mL of acetone, add 6 g of hyperbranched polyester polyol, and 0.016 g of dibutyltin dilaurate, react for 1 h, add 130 mL of distilled water, concentrate under reduced pressure to remove acetone, add 0.26 g of defoamer Foamaster MO 2134 and 0.17 g of leveling agent BYK-3760, and shear disperse to obtain a hyperbranched waterborne polyurethane.

[0031] Example 5

[0032] (1) Add 100 mL of N,N-dimethylformamide, 1 mmol of trimethylolpropane, 9 mmol of sodium sulfonate-based AB2 monomer, and 0.035 mmol of p-toluenesulfonic acid into a reaction flask, introduce nitrogen, heat to 150° C., and react for 6 h; then add 36 mmol of sodium sulfonate-based AB2 monomer (prepared in Example 3) and 0.145 mmol of p-toluenesulfonic acid, continue to react for 18 h, remove low-boiling substances by distillation under reduced pressure, and dry to obtain a hyperbranched polyester polyol containing sodium sulfonate groups.

[0033] (2) Add 50 mmol (100 g) of dried and dehydrated polycaprolactone diol 2000 and 120 mmol (30 g) of 4,4'-methylenebis(phenyl isocyanate) into a reaction flask, introduce nitrogen, heat to 75°C, react for 2 h, then lower the temperature to 45°C, add 50 mL of acetone, add 12.2 g of hyperbranched polyester polyol, and 0.016 g of dibutyltin dilaurate, react for 1.5 h, add 130 mL of distilled water, concentrate under reduced pressure to remove acetone, add 0.26 g of defoamer Foamaster MO 2134 and 0.17 g of leveling agent BYK-3760, and shear and disperse to obtain a hyperbranched waterborne polyurethane.

[0034] Example 6

[0035] (1) Add 100 mL of N,N-dimethylformamide, 1 mmol of trimethylolpropane, 9 mmol of sodium sulfonate AB2 monomer, and 0.035 mmol of p-toluenesulfonic acid into a reaction flask, introduce nitrogen, heat to 140° C., and react for 8 h; then add 36 mmol of sodium sulfonate AB2 monomer (prepared by Example 3) and 0.145 mmol of p-toluenesulfonic acid, continue to react for 18 h, remove low-boiling substances by distillation under reduced pressure, and dry to obtain a hyperbranched polyester polyol containing sodium sulfonate groups.

[0036] (2) Add 50 mmol (100 g) of dried and dehydrated polybutylene adipate diol 2000 and 120 mmol (27.4 g) of isophorone diisocyanate to a reaction flask, introduce nitrogen, raise the temperature to 70° C., react for 3 h, then lower the temperature to 50° C., add acetone, add 19 g of hyperbranched polyester polyol, and 0.016 g of dibutyltin dilaurate, react for 1.5 h, add 130 mL of distilled water, concentrate under reduced pressure to remove acetone, add 0.26 g of defoamer Foamaster MO 2134 and 0.17 g of leveling agent BYK-3760, and shear and disperse to obtain a hyperbranched waterborne polyurethane.

[0037] Comparative Example 1

[0038] (1) Add 50 mmol (100 g) of dried and dehydrated polycarbonate diol 2000 and 120 mmol (20.9 g) of toluene-2,4-diisocyanate to a reaction flask, introduce nitrogen, raise the temperature to 70°C, react for 3 h, then lower the temperature to 45°C, add 50 mL of acetone, add 6 g of 1,2-dihydroxy-3-propanesulfonic acid (structural formula: ), 0.016g of dibutyltin dilaurate, react for 1h, add 130mL of distilled water, add triethylamine dropwise for neutralization, concentrate under reduced pressure to remove acetone, add 0.26g of defoamer Foamaster MO 2134 and 0.17g of leveling agent BYK-3760, shear and disperse, and obtain waterborne polyurethane.

[0039] Comparative Example 2

[0040] (1) Add 60 mL of N,N-dimethylformamide, 1 mmol of trimethylolpropane, 9 mmol of 2,2-dimethylolpropionic acid, and 0.035 mmol of p-toluenesulfonic acid into a reaction flask, introduce nitrogen, raise the temperature to 140° C., and react for 7 h; then add 12 mmol of 2,2-dimethylolpropionic acid and 0.045 mmol of p-toluenesulfonic acid, continue the reaction for 10 h, remove low-boiling substances by distillation under reduced pressure, and dry to obtain a hyperbranched polyester polyol.

[0041] (2) Add 50 mmol (100 g) of dried and dehydrated polycarbonate diol 2000 and 120 mmol (20.9 g) of toluene-2,4-diisocyanate to a reaction flask, introduce nitrogen, heat to 70°C, react for 3 h, then lower the temperature to 45°C, add 50 mL of acetone, add 6 g of hyperbranched polyester polyol, and 0.016 g of dibutyltin dilaurate, react for 1 h, add 130 mL of distilled water, concentrate under reduced pressure to remove acetone, add 0.26 g of defoamer Foamaster MO 2134 and 0.17 g of leveling agent BYK-3760, and shear and disperse to obtain a hyperbranched polyurethane.

[0042] The emulsion stability of polyurethane was tested according to GB / T 6753.3-1986 method.

[0043] Table 1 Emulsion stability test of polyurethane.

[0044] Storage time (month) Emulsion stability Example 4 ≧8 No precipitation, no stratification Example 5 ≧8 No precipitation, no stratification Example 6 ≧7 No precipitation, no stratification Comparative Example 1 ≧5 There is obvious precipitation Comparative Example 2 ≧8 No precipitation, no stratification

[0045] Pour the polyurethane emulsion into the mold, cure it at 60℃ for 3h, and then cure it at 100℃ for 6h to make a sample. Test the tensile properties of the sample according to GB / T 1040.1-2018. Test the bending properties of polyurethane according to GB / T9341-2008. Test the Shore A hardness of the sample according to GB / T 2411-2008.

[0046] Weigh the polyurethane sample (m0), soak it in distilled water for 24 hours, take out the sample, wipe off the surface moisture, weigh it (m1), and calculate the water absorption W. W = (m1-m0) / m0×100%.

[0047] Table 2 Polyurethane performance test

[0048]

[0049] After testing, in each embodiment, the hyperbranched polyester polyol is used as the chain extender of polyurethane, and the terminal isocyanate polyurethane prepolymer generated by the reaction of the polyol compound and the diisocyanate compound is subjected to chain extension and crosslinking reaction. The molecular chain of the obtained hyperbranched waterborne polyurethane contains a large amount of sodium sulfonate hydrophilic groups, which improves the water solubility of the hyperbranched waterborne polyurethane, has good dispersibility in the water medium, strong emulsion stability, and long storage time. And the terminal position of the hyperbranched polyester polyol contains a large amount of hydroxyl groups, which reacts with the terminal isocyanate polyurethane prepolymer to form a hyperbranched crosslinking network in the polyurethane, improves the molecular chain crosslinking degree of the polyurethane, forms a dense crosslinking network, can inhibit water molecules from entering the polyurethane matrix, is conducive to reducing water absorption, and improves the water resistance of waterborne polyurethane. At the same time, the polyurethane with a hyperbranched crosslinking network has better mechanical properties. The tensile strength reaches up to 40.5MPa, the elongation at break reaches 680.1%, the bending strength reaches 85.5MPa, and the Shore A hardness reaches 87.

[0050] Comparative Example 1 uses existing 1,2-dihydroxy-3-propanesulfonic acid as a hydrophilic chain extender, and the obtained waterborne polyurethane has good dispersibility in water medium, strong emulsion stability, and long storage time. However, the polyurethane is a linear molecular chain, does not contain a hyperbranched cross-linked network structure, has a large water absorption rate, poor water resistance, and low tensile properties, bending strength, Shore A hardness, and poor mechanical properties.

[0051] Compared with Example 4, Comparative Example 2 uses existing trimethylolpropane and 2,2-dimethylolpropionic acid as raw materials to prepare a hyperbranched polyester polyol with terminal hydroxyl groups. Using it as a chain extender, the prepared hyperbranched polyurethane does not contain sulfonic acid hydrophilic groups, has poor dispersibility in aqueous media, poor emulsion stability, and a short storage time. And the tensile properties, bending strength, and Shore A hardness are lower than those of Example 4. It may be that the hyperbranched polyester polyol in Example 4 contains a rigid aromatic ring structure, which is stronger and has a better effect on improving the mechanical strength of the polyurethane. The hyperbranched polyurethane of Comparative Example 2 also has a hyperbranched cross-linked network, with a high degree of molecular chain cross-linking, which can form a dense cross-linked network, inhibit water molecules from entering the interior of the polyurethane matrix, and is conducive to reducing the water absorption rate, which is only 5.5%. Although the hyperbranched waterborne polyurethane of Example 4 contains hydrophilic sulfonic acid groups, its water absorption rate is 5.9%, which is not much different from each other. It may be that the hyperbranched polyurethane of Example 4 contains hydrophobic aromatic rings and alkyl segments, which can reduce the water absorption rate of the polyurethane.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing a hyperbranched polyester polyol, characterized in that: The preparation process comprises: adding N,N-dimethylformamide, trimethylolpropane, sodium sulfonate-based AB2 monomer and p-toluenesulfonic acid into a reaction bottle, introducing nitrogen, heating to the reaction temperature, and reacting for 6-8 hours; then adding sodium sulfonate-based AB2 monomer and p-toluenesulfonic acid, continuing the reaction for 10-18 hours, removing low-boiling substances by reduced pressure distillation, and drying to obtain a hyperbranched polyester polyol containing sodium sulfonate groups; The structural formula of the sodium sulfonate-based AB2 monomer is formula (I):

2. The preparation process of hyperbranched polyester polyol according to claim 1, characterized in that: The molar ratio of the trimethylolpropane, the sodium sulfonate-based AB2 monomer, and p-toluenesulfonic acid is 1:(21-45):(0.08-0.18).

3. The preparation process of hyperbranched polyester polyol according to claim 1, characterized in that: The reaction temperature is 140-150°C.

4. The preparation process of hyperbranched polyester polyol according to claim 1, characterized in that: The preparation process of the sodium sulfonate-based AB2 monomer is as follows: (1) Add methanol, 3,5-diaminobenzoic acid, and 5-hydroxyvaleraldehyde to a reaction flask, heat to 35-45° C., react for 2-5 hours, then cool to room temperature, add sodium borohydride, react for 10-15 hours, cool the reaction flask in an ice water bath, add dilute hydrochloric acid to adjust the pH of the solution to 4-5, stir to precipitate, filter, wash, and dry to obtain an AB2 precursor; (2) Adding a solvent, an AB2 precursor, sodium 2-bromoethane sulfonate, and triethylamine to a reaction flask, reacting at room temperature for 12-18 hours, concentrating under reduced pressure, washing, and recrystallizing to obtain a sodium sulfonate-based AB2 monomer.

5. The preparation process of hyperbranched polyester polyol according to claim 4, characterized in that: The molar ratio of 3,5-diaminobenzoic acid, 5-hydroxyvaleraldehyde and sodium borohydride in (1) is 1:(2.1-2.4):(2-2.2).

6. The preparation process of hyperbranched polyester polyol according to claim 4, characterized in that: The solvent in (2) is methanol, ethanol or tetrahydrofuran.

7. The preparation process of hyperbranched polyester polyol according to claim 4, characterized in that: The molar ratio of the AB2 precursor, sodium 2-bromoethanesulfonate and triethylamine in (2) is 1:(2.2-2.8):(2.2-2.8).

8. Use of a hyperbranched polyester polyol obtained by the preparation process according to any one of claims 1 to 7 in a hyperbranched waterborne polyurethane, characterized in that: Add dried and dehydrated polyol compounds and diisocyanate compounds into a reaction bottle, introduce nitrogen, heat to 70-75°C, react for 2-3 hours, then reduce the temperature to 45-50°C, add acetone, add hyperbranched polyester polyol and dibutyltin dilaurate, react for 1-1.5 hours, add distilled water, concentrate under reduced pressure to remove acetone, add a defoamer and a leveling agent, and shear and disperse to obtain a hyperbranched waterborne polyurethane.

9. The use of the hyperbranched polyester polyol according to claim 8 in hyperbranched waterborne polyurethane, wherein the characteristic effects are: The polyol compound includes polybutylene adipate diol, polycarbonate diol, and polycaprolactone diol; the diisocyanate compound includes isophorone diisocyanate, toluene-2,4-diisocyanate, and 4,4'-methylenebis(phenyl isocyanate).

10. The use of the hyperbranched polyester polyol according to claim 8 in hyperbranched waterborne polyurethane, wherein the characteristic effect is: The hyperbranched polyester polyol accounts for 5-18% of the total mass of the polyol compound and the diisocyanate compound.

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