Sulfonate polyester polyol and preparation method thereof

Abstract

The invention discloses sulfonate polyester polyol and a preparation method thereof, the sulfonate polyester polyol is prepared by taking m-phthalic acid-5-sulfonate, 2-(diethanolamine) ethanesulfonate, aliphatic dibasic acid, ethylene glycol and triethylene glycol as raw materials through reaction, and the preparation method comprises the steps of pre-esterification reaction, condensation polymerization reaction and post-treatment. Wherein the polycondensation reaction is carried out in two stages, namely normal-pressure esterification is carried out firstly, and then heating and vacuumizing polycondensation are carried out. The sulfonate polyester polyol has high hydrophilicity, low-temperature flexibility and low surface resistance, the hydroxyl value is 30-90 mg KOH / g, the acid value is smaller than or equal to 3 mg KOH / g, and the hue Alpha value is smaller than 30.

Description

Technical Field

[0001] This invention belongs to the field of functional polyester polyol synthesis technology, and relates to sulfonate polyester polyols and their preparation methods, specifically to sulfonate polyester polyols containing disulfonate groups (-SO3M) and amino intermediates and their preparation methods. Background Technology

[0002] Currently, sulfonate polyester polyols mainly use sodium dimethyl isophthalate-5-sulfonate as the sulfonation source, requiring high-temperature transesterification. This process suffers from low sulfonation efficiency, a wide molecular weight distribution (PDI ≥ 1.5), and the use of a single sulfonate leads to a contradiction between hydrophilicity and mechanical properties. For example, while high sulfonation improves water dispersibility, it deteriorates low-temperature toughness. Furthermore, the excessive spatial distance between sulfonates results in poor electrical conductivity. In existing processes, catalysts are prone to hydrolysis (e.g., titanates), leading to deactivation, increased side reactions, higher acid values ​​(> 3 mg KOH / g), and color degradation (Alpha value ≥ 50).

[0003] Most research on sulfonate polyester polyols focuses on synthesis and process adjustment. Imparting special properties to materials through molecular structure regulation and process improvement has always been a key research direction. However, current sulfonate polyester polyols use highly reactive small molecule diols, which are prone to high molecular weight polyesters through high-temperature polycondensation. Molecular weight control is difficult, and they cannot be well dissolved in organic solvents, only dissolving to a limited extent in hot water. This makes them unsuitable for some applications that require anhydrous solutions.

[0004] In summary, developing a functional sulfonate polyester polyol that combines hydrophilicity, low flexibility, and low surface resistance has significant application value. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a sulfonate polyester polyol with high hydrophilicity, low flexibility and low surface resistance and its preparation method.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0007] A sulfonate polyester polyol, wherein the sulfonate polyester polyol is prepared by reacting isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, aliphatic dicarboxylic acid, ethylene glycol, and triethylene glycol as raw materials, and the chemical structural formula of the sulfonate polyester polyol contains a sulfonated aromatic ring unit as shown in formula (I) and a tertiary amine-sulfonic acid side chain as shown in formula (II):

[0008] In formula (I), M1 is an alkali metal; in formula (II), M2 is an alkali metal. The sulfonate polyester polyol has a hydroxyl value of 30 mg KOH / g to 90 mg KOH / g, an acid value of ≤3 mg KOH / g, and a hue alpha value of <30.

[0009] Preferably, the sulfonate polyester polyols mentioned above include one or more of lithium isophthalate-5-sulfonate, lithium dimethyl isophthalate-5-sulfonate, sodium dimethyl isophthalate-5-sulfonate, and sodium isophthalate-5-sulfonate.

[0010] In the above-mentioned sulfonate polyester polyols, preferably, in formula (I) M1 is Li or Na, and in formula (II) M2 is Li or Na.

[0011] The aforementioned sulfonate polyester polyols, preferably, contain one or more of adipic acid, sebacic acid, and succinic acid, more preferably adipic acid.

[0012] The sulfonate polyester polyols mentioned above, preferably, include lithium 2-(diethanolamine)ethanesulfonate and / or sodium 2-(diethanolamine)ethanesulfonate, more preferably lithium 2-(diethanolamine)ethanesulfonate.

[0013] Preferably, the preparation process of the sulfonate polyester polyol is as follows: 2-(diethanolamine)ethanesulfonic acid and lithium hydroxide are added to water for neutralization reaction, and after drying, lithium 2-(diethanolamine)ethanesulfonic acid is obtained; wherein, the molar ratio of 2-(diethanolamine)ethanesulfonic acid to lithium hydroxide is 1:1, and the drying includes first evaporating the water, and then vacuum drying at 240℃~260℃ for 3h~5h.

[0014] Preferably, the surface resistivity of the polymer film obtained by curing the sulfonate polyester polyol is <10×10⁻⁶. 8 Ω·cm, no cracks when bent at -30℃, the sulfonate polyester polyol is miscible with water.

[0015] As a general technical concept, the present invention also provides a method for preparing the above-mentioned sulfonate polyester polyol, comprising the following steps: (1) Pre-esterification reaction: 5-sulfonate isophthalic acid, 2-(diethanolamine) ethanesulfonate, ethylene glycol, triethylene glycol and catalyst are added to the reaction vessel and heated to 180℃~200℃ under nitrogen protection to carry out the pre-esterification reaction and generate sulfonated diol intermediate. (2) Polycondensation reaction: The sulfonated diol intermediate, aliphatic diacid and antioxidant are mixed and the reaction is carried out in two stages. The first reaction stage is to carry out atmospheric pressure esterification at 160℃~190℃, remove water until the acid value is ≤10mg KOH / g, and generate polyester oligomer. The second reaction stage is to add catalyst, then raise the temperature to 220℃~240℃, and then vacuum at this temperature to polycondense until the hydroxyl value is 30mg KOH / g~90mg KOH / g and the acid value is ≤3mg KOH / g, to obtain crude sulfonate polyester polyol product. (3) Post-processing: The crude product of the sulfonate polyester polyol is dissolved and precipitated for purification, and then dehydrated under reduced pressure to obtain the sulfonate polyester polyol with a color Alpha value <30.

[0016] In the above-mentioned method for preparing sulfonate polyester polyols, preferably, the sum of the mass of the catalyst in step (1) and the catalyst in step (2) is 0.08wt% to 0.1wt% of the total mass of isophthalic acid-5-sulfonate, 2-(diethanolamine) ethanesulfonate, ethylene glycol, triethylene glycol and aliphatic dicarboxylic acid.

[0017] In the above-mentioned method for preparing sulfonate polyester polyol, preferably, in step (1), the molar ratio of isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, ethylene glycol, and triethylene glycol is 1:0.2 to 0.5:5:1 to 2, and the amount of catalyst added is 60% to 70% of the total mass of the catalyst in steps (1) and (2).

[0018] In the above-mentioned method for preparing sulfonate polyester polyol, preferably, the molar ratio of the aliphatic dicarboxylic acid in step (2) to the isophthalic acid-5-sulfonate in step (1) is 0.5 to 1:1, and the amount of catalyst added in step (2) is 30% to 40% of the total mass of the catalyst in steps (1) and (2).

[0019] In the above-mentioned method for preparing sulfonate polyester polyols, preferably, the catalyst in steps (1) and (2) is antimony glycolate.

[0020] In the preferred method for preparing the sulfonate polyester polyol described above, in step (2), the antioxidant is triphenyl phosphite, and the amount of antioxidant used in step (2) is 0.05wt% to 0.1wt% of the total mass of isophthalic acid-5-sulfonate, 2-(diethanolamine) ethanesulfonate, ethylene glycol, triethylene glycol and aliphatic dicarboxylic acid.

[0021] In the above-mentioned method for preparing sulfonate polyester polyol, preferably, in step (1), the esterification reaction time is 3h to 5h.

[0022] In the preferred method for preparing the sulfonate polyester polyol described above, in step (2), during the second reaction stage, the heating rate is 8℃ / h to 10℃ / h, and the vacuum is evacuated to 0 to -0.1MPa.

[0023] In the above-mentioned method for preparing sulfonate polyester polyol, preferably, in step (3), the solvent used for the dissolution-precipitation purification is a mixture of acetone and water, and the mass ratio of acetone to water in the mixture of acetone and water is 1:0.8 to 1.

[0024] The main innovative points of this invention are as follows: (1) Synergistic effect of dual sulfonates: isophthalic acid-5-sulfonate provides hydrophilicity of the main chain as a rigid sulfonation unit of the main chain, while the flexible chain extender 2-(diethanolamine) ethanesulfonate has both sulfonic acid group and tertiary amine group, which can synergistically improve water dispersibility with carboxyl sulfonate. The tertiary amine group promotes autocatalytic esterification, reduces the amount of catalyst used, and inhibits side reactions. (2) Low resistance and high conductivity: The double sulfonate structure increases the concentration of sulfonates in the molecular chain and reduces the spatial distance between sulfonates. The aliphatic long-chain dicarboxylic acid enhances the flexibility of the chain segments. The flexible main chain can promote efficient complexation with alkali metal salts, thereby improving the migration efficiency of ions in the polymer, reducing resistance and increasing conductivity. Carboxyl sulfonates and hydroxy sulfonates are arranged alternately through an alcohol-acid condensation reaction.

[0025] (3) Segmented controlled compression polymerization: After atmospheric pressure esterification, vacuuming is delayed (until the acid value is ≤10mg KOH / g) to avoid catalyst hydrolysis and deactivation, and the ethylene glycol generated by hydrolysis can participate in the reaction; (4) Mixed diol design: The glass transition temperature (Tg=-30℃~10℃) can be controlled by the ratio of ethylene glycol (EG, rigid chain) / triethylene glycol (TEG, flexible chain with ether bond) to improve low-temperature film formation.

[0026] The reaction process involved in the preparation of the sulfonate polyester polyol of the present invention is shown below, with M1 and M2 taking Li and Na as examples:

[0027] in,

[0028] Compared with the prior art, the advantages of the present invention are as follows: (1) The sulfonate polyester polyol of the present invention introduces a double sulfonate structure into the polymer chain by using two hydrophilic monomers of sulfonate, which improves the degree of sulfonation of the polymer chain and gives the material good hydrophilicity. At the same time, by mixing the diol system (EG+TEG), the hydrophilic groups are uniformly embedded. The proportion of the molecular chain in the diol system (EG+TEG) can be adjusted to achieve flexible control of the molecular chain. The molecular structure is rationally designed to solve the problem of performance imbalance.

[0029] (2) The introduction of 2-(diethanolamino)ethanesulfonate in this invention not only increases the content of sulfonate segments in the molecular chain, but also the special structure of the amine intermediate of 2-(diethanolamino)ethanesulfonate (such as lithium 2-(diethanolamino)ethanesulfonate) forms a bidentate ligand with the adjacent hydroxyl group (-OH), which reacts with Li + Constructing a stable five-membered ring chelate structure (similar to crown ethers) significantly reduces Li + The removal of the energy barrier of sulfonate groups further improves the conductivity of polyester, making it easier to design the molecular structure of polyester. This allows polyurethane prepared from polyester to maintain good low-temperature flexibility even with sufficiently low surface resistance.

[0030] (3) The preparation method of the present invention adopts a stepwise catalytic and pressure-controlled approach to reduce the loss of diols and obtain sulfonate polyester polyols with narrow molecular weight distribution (PDI≤1.3) and low acid value (≤3mg KOH / g). In the preparation method of the present invention, the first step is a low-temperature catalytic pre-esterification reaction of acid and diol to obtain a sulfonated diol intermediate. At this time, the alcohol component has a high molecular weight, which reduces the loss of raw material diols. The subsequent atmospheric pressure esterification yields polyester oligomers. The addition of catalyst to raise the temperature and vacuum polycondensation accelerate the reaction while removing small molecule monomers and impurities, promoting the esterification reaction and increasing the polyester molecular weight. Attached Figure Description

[0031] Figure 1 The image shows the FT-IR spectrum of the sulfonate polyester polyol prepared in Example 1 of this invention. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. The materials and instruments used in the following embodiments are all commercially available. Lithium isophthalic acid-5-sulfonate and sodium isophthalic acid-5-sulfonate were purchased from Jiaozuo Runyang Chemical Technology Co., Ltd., sodium 2-(diethanolamine)ethanesulfonate was purchased from Shanghai Cente Biotechnology Co., Ltd., 2-(diethanolamine)ethanesulfonic acid was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd., and lithium hydroxide was purchased from Shanghai Oujin Industrial Co., Ltd., but are not limited thereto. In the following embodiments, atmospheric pressure refers to 0.1 MPa. The acid value was determined by titration, and the hydroxyl value was determined by acetylation.

[0033] Example 1 A sulfonate polyester polyol of the present invention is prepared by reacting isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, aliphatic dicarboxylic acid, ethylene glycol, and triethylene glycol as reactants. The chemical structure of the sulfonate polyester polyol contains a sulfonated aromatic ring unit as shown in formula (I) and a tertiary amine-sulfonic acid side chain as shown in formula (II).

[0034] In formula (I), M1 is the alkali metal Li, and in formula (II), M2 is the alkali metal Li.

[0035] In this embodiment, the hydroxyl value of the sulfonate polyester polyol is 65 mg KOH / g, the acid value is 2 mg KOH / g, and the hue alpha value is 25.

[0036] In this embodiment, 5-isophthalic acid sulfonate is lithium 5-isophthalic acid sulfonate.

[0037] In this embodiment, 2-(diethanolamine)ethanesulfonate is lithium 2-(diethanolamine)ethanesulfonate.

[0038] The preparation process of lithium 2-(diethanolamino)ethanesulfonate is as follows: 2-(diethanolamino)ethanesulfonic acid and lithium hydroxide are added to water at a molar ratio of 1:1 for neutralization reaction. After the reaction, the water is evaporated and dried under vacuum at 240℃ for 3 hours to obtain lithium 2-(diethanolamino)ethanesulfonate.

[0039] In this embodiment, the aliphatic dicarboxylic acid is adipic acid.

[0040] A method for preparing sulfonate polyester polyol according to this embodiment includes the following steps: (1) Pre-esterification reaction: Lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and antimony glycol catalyst are added to the reaction vessel and heated to 190℃~200℃ for 3 hours under nitrogen protection to generate sulfonated diol intermediate. (2) Polycondensation reaction: The sulfonated diol intermediate, adipic acid and antioxidant triphenyl phosphite are mixed and reacted in two stages. The first reaction stage is esterification at 180 °C under normal pressure, and water is removed until the acid value is 9 mg KOH / g (≤10 mg KOH / g) to obtain polyester oligomer. In the second reaction stage, antimony glycolate is added to the polyester oligomer, and the temperature is raised to 230 °C-240 °C at 8-10 °C / h. At this temperature, a vacuum is drawn to -0.08 MPa and polycondensation continues for 4 hours until the hydroxyl value is 65 mg KOH / g and the acid value is 2 mg KOH / g to obtain the crude product of sulfonate polyester polyol.

[0041] (3) Post-processing: The crude product of sulfonate polyester polyol was purified by dissolution-precipitation using a mixture of acetone and water. The mass ratio of acetone to water in the mixture was 1:1. After dehydration under reduced pressure, sulfonate polyester polyol was obtained with a hue Alpha value of 25.

[0042] In this embodiment, the sum of the masses of antimony glycolate in step (1) and antimony glycolate in step (2) is 0.1 wt% of the total mass of lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0043] In step (1) of this embodiment, the molar ratio of lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, and triethylene glycol is 1:0.5:5:1.5, and the mass of antimony glycol is 60% of the total mass of antimony glycol in steps (1) and (2).

[0044] In this embodiment, the molar ratio of adipic acid in step (2) to lithium isophthalic acid-5-sulfonate in step (1) is 1:1, and the amount of antimony glycolate added in step (2) is 40% of the total mass of antimony glycolate in steps (1) and (2).

[0045] In this embodiment, the amount of antioxidant used is 0.1 wt% of the total mass of lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0046] Figure 1 The FT-IR spectrum of the product in this embodiment is shown below. Figure 1 As shown, at 3435 cm - The peak at ¹ represents the absorption peak of the hydroxyl stretching vibration, located at 1722 cm⁻¹. - The peak at ¹ represents the absorption peak of the carbonyl stretching vibration of the ester, indicating that the reaction has proceeded. The peak is located at 1183 cm⁻¹. - ¹and 1041cm - The peak at position ¹ represents the symmetric / antisymmetric vibrational absorption peak of the sulfonate group, confirming the presence of sulfonate in the product. The infrared spectra of products from other examples are similar. Figure 1 They are basically the same.

[0047] Product performance: The sulfonate polyester polyol prepared in this embodiment was tested and found to have a hydroxyl value of 65 mg KOH / g, an acid value of 2 mg KOH / g, an alpha value of 25, water miscibility, and a PDI of 1.2. The product was diluted to 50% with ethyl acetate as the polyol component. 10% (by weight) of Covestro XP 2655 curing agent was added to the polyol, and after thorough mixing, a 10 μm thick dry film was coated onto PET and cured at 50°C for 48 h. The surface resistivity was measured to be 2.63 × 10⁻⁶. 6 Ω·cm, Low-temperature bending performance (-30℃, 2mm standard shaft, 180° bend): No cracks.

[0048] Example 2 A sulfonate polyester polyol of the present invention is prepared by esterification-polymerization reaction using isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, aliphatic dicarboxylic acid, ethylene glycol, and triethylene glycol as reactants. The chemical structure of the sulfonate polyester polyol contains a sulfonated aromatic ring unit as shown in formula (I) and a tertiary amine-sulfonic acid side chain as shown in formula (II).

[0049] In formula (I), M1 is the alkali metal Li, and in formula (II), M2 is the alkali metal Li.

[0050] In this embodiment, the hydroxyl value of the sulfonate polyester polyol is 59 mg KOH / g, the acid value is 2.3 mg KOH / g, and the hue alpha value is 27.

[0051] In this embodiment, 5-isophthalic acid sulfonate is lithium 5-isophthalic acid sulfonate.

[0052] In this embodiment, 2-(diethanolamine)ethanesulfonate is lithium 2-(diethanolamine)ethanesulfonate.

[0053] The preparation process of lithium 2-(diethanolamino)ethanesulfonate is as follows: 2-(diethanolamino)ethanesulfonic acid and lithium hydroxide are added to water at a molar ratio of 1:1 for neutralization reaction. After the reaction, the water is evaporated and dried under vacuum at 240℃ for 3 hours to obtain lithium 2-(diethanolamino)ethanesulfonate.

[0054] In this embodiment, the aliphatic dicarboxylic acid is adipic acid.

[0055] A method for preparing sulfonate polyester polyol according to this embodiment includes the following steps: (1) Pre-esterification reaction: Lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and antimony glycol are added to the reaction vessel and pre-esterified at 190℃~200℃ for 3 hours under nitrogen protection to generate sulfonated diol intermediate. (2) Polycondensation reaction: The sulfonated diol intermediate, adipic acid and antioxidant triphenyl phosphite are mixed and reacted in two stages. The first reaction stage is esterification at atmospheric pressure at 180℃, and water is removed until the acid value is 9 mg KOH / g to obtain polyester oligomer. In the second reaction stage, antimony glycol is added and the temperature is raised to 230℃-240℃ at 8-10℃ / h. At this temperature, a vacuum is drawn to -0.08MPa and polycondensation continues for 4 hours until the hydroxyl value is 59 mg KOH / g and the acid value is 2.3 mg KOH / g to obtain crude sulfonate polyester polyol.

[0056] (3) Post-processing: The crude product of sulfonate polyester polyol was purified by dissolution-precipitation using a mixture of acetone and water. The mass ratio of acetone to water in the mixture was 1:1. After dehydration under reduced pressure, sulfonate polyester polyol was obtained with a hue Alpha value of 27.

[0057] In this embodiment, the sum of the masses of antimony glycolate in step (1) and antimony glycolate in step (2) is 0.1 wt% of the total mass of lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0058] In step (1) of this embodiment, the molar ratio of lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, and triethylene glycol is 1:0.3:5:2, and the mass of antimony glycol is 60% of the total mass of antimony glycol in steps (1) and (2).

[0059] In this embodiment, the molar ratio of adipic acid in step (2) to lithium isophthalic acid-5-sulfonate in step (1) is 0.5:1, and the amount of antimony glycolate added in step (2) is 40% of the total mass of antimony glycolate in steps (1) and (2).

[0060] In this embodiment, the amount of antioxidant used is 0.1 wt% of the total mass of lithium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0061] Product performance: The sulfonate polyester polyol prepared in this embodiment was tested and found to have a hydroxyl value of 59 mg KOH / g, an acid value of 2.3 mg KOH / g, an alpha value of 27, water miscibility, and a PDI of 1.3. The product was diluted to 50% with ethyl acetate as the polyol component. 10% (by weight) of Covestro XP 2655 curing agent was added to the polyol, and after thorough mixing, a 10 μm thick dry film was coated onto PET and cured at 50°C for 48 hours. The surface resistivity was measured to be 6.56 × 10⁻⁶. 7Ω·cm, Low-temperature bending performance (-30℃, 2mm standard shaft, 180° bend): No cracks.

[0062] Example 3 A sulfonate polyester polyol of the present invention is prepared by esterification-polymerization reaction using isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, aliphatic dicarboxylic acid, ethylene glycol, and triethylene glycol as reactants. The chemical structure of the sulfonate polyester polyol contains a sulfonated aromatic ring unit as shown in formula (I) and a tertiary amine-sulfonic acid side chain as shown in formula (II).

[0063] In formula (I), M1 is the alkali metal Na, and in formula (II), M2 is the alkali metal Na.

[0064] In this embodiment, the sulfonate polyester polyol has a hydroxyl value of 60 mg KOH / g, an acid value of 2.5 mg KOH / g, and a hue alpha value of 28.

[0065] In this embodiment, isophthalic acid-5-sulfonate is sodium isophthalic acid-5-sulfonate.

[0066] In this embodiment, 2-(diethanolamino)ethanesulfonate is sodium 2-(diethanolamino)ethanesulfonate.

[0067] In this embodiment, the aliphatic dicarboxylic acid is adipic acid.

[0068] A method for preparing sulfonate polyester polyol according to this embodiment includes the following steps: (1) Pre-esterification reaction: Sodium isophthalic acid-5-sulfonate, sodium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and antimony glycol are added to the reaction vessel and heated to 190℃~200℃ for 3 hours under nitrogen protection to generate sulfonated diol intermediate. (2) Polycondensation reaction: The sulfonated diol intermediate, adipic acid and antioxidant triphenyl phosphite are mixed and reacted in two stages. The first reaction stage is esterification at 180℃ under normal pressure, and water is removed until the acid value is 9 mg KOH / g to obtain polyester oligomer. In the second reaction stage, antimony glycol is added and the temperature is raised to 230℃-240℃ at 8-10℃ / h. At this temperature, a vacuum is drawn to -0.08MPa and polycondensation continues for 4 hours until the hydroxyl value is 60 mg KOH / g and the acid value is 2.5 mg KOH / g to obtain crude sulfonate polyester polyol.

[0069] (3) Post-processing: The crude product of sulfonate polyester polyol was purified by dissolution-precipitation using a mixture of acetone and water. The mass ratio of acetone to water in the mixture was 1:1. After dehydration under reduced pressure, sulfonate polyester polyol was obtained with a hue Alpha value of 28.

[0070] In this embodiment, the sum of the masses of antimony glycolate in step (1) and antimony glycolate in step (2) is 0.1 wt% of the total mass of sodium isophthalate-5-sulfonate, sodium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0071] In step (1) of this embodiment, the molar ratio of sodium isophthalate-5-sulfonate, sodium 2-(diethanolamine)ethanesulfonate, ethylene glycol, and triethylene glycol is 1:0.5:5:1.5, and the mass of antimony glycol is 60% of the total mass of antimony glycol in steps (1) and (2).

[0072] In this embodiment, the molar ratio of adipic acid in step (2) to sodium isophthalic acid-5-sulfonate in step (1) is 1:1, and the amount of antimony glycolate added in step (2) is 40% of the total mass of antimony glycolate in steps (1) and (2).

[0073] In this embodiment, the amount of antioxidant used is 0.1 wt% of the total mass of sodium isophthalate-5-sulfonate, sodium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0074] Product performance: The sulfonate polyester polyol prepared in this embodiment was tested and found to have a hydroxyl value of 60 mg KOH / g, an acid value of 2.5 mg KOH / g, an alpha value of 28, a PDI of 1.3, and was miscible with water. The product was diluted to 50% with ethyl acetate as the polyol component. 10% (by weight) of Covestro XP 2655 curing agent was added to the polyol, and after thorough mixing, a 10 μm thick dry film was coated onto PET and cured at 50°C for 48 hours. The surface resistivity was measured to be 1.22 × 10⁻⁶. 7 Ω·cm, Low-temperature bending performance (-30℃, 2mm standard shaft, 180° bend): No cracks.

[0075] Comparative Example 1 A sulfonate polyester polyol, which is prepared by esterification-condensation reaction using isophthalic acid-5-sulfonate, aliphatic dicarboxylic acid, ethylene glycol, and triethylene glycol as reactants, wherein the chemical structure of the sulfonate polyester polyol contains a sulfonated aromatic ring unit as shown in formula (I):

[0076] In formula (Ⅰ), M1 is the alkali metal Li.

[0077] In this comparative example, the hydroxyl value of the sulfonate polyester polyol was 68 mg KOH / g, the acid value was 3.9 mg KOH / g, and the hue alpha value was 60.

[0078] In this comparative example, 5-isophthalic acid sulfonate is lithium 5-isophthalic acid sulfonate.

[0079] In this comparative example, the aliphatic dicarboxylic acid is adipic acid.

[0080] A method for preparing a sulfonate polyester polyol includes the following steps: (1) Pre-esterification reaction: Lithium isophthalic acid-5-sulfonate, ethylene glycol, triethylene glycol and antimony glycol are added to the reaction vessel and heated to 190 ℃~200 ℃ for 3 hours under nitrogen protection to generate sulfonated diol intermediate; (2) Polycondensation reaction: Sulfonated diol intermediate, adipic acid and antioxidant triphenyl phosphite are mixed and reacted in two stages. The first reaction stage is esterification at atmospheric pressure at 180℃, and water is removed until the acid value is 9 mg KOH / g. In the second reaction stage, antimony glycol is added and the temperature is raised to 230℃-240℃ at 8-10℃ / h. At this temperature, the vacuum is drawn to -0.08MPa and polycondensation continues for 4 hours. The hydroxyl value is 68 mg KOH / g and the acid value is 3.9 mg KOH / g, and the crude product of sulfonate polyester polyol is obtained. (3) Post-treatment: The crude product of sulfonate polyester polyol was purified by dissolution-precipitation using a mixture of acetone and water. The mass ratio of acetone to water in the mixture was 1:1. After dehydration under reduced pressure, sulfonate polyester polyol was obtained with a hue Alpha value of 60.

[0081] In this comparative example, the sum of the masses of antimony glycolate in step (1) and antimony glycolate in step (2) is 0.1 wt% of the total mass of lithium isophthalic acid-5-sulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0082] In step (1) of this comparative example, the molar ratio of lithium isophthalic acid-5-sulfonate, ethylene glycol, and triethylene glycol is 1:5:1, and the mass of antimony glycol is 60% of the total mass of antimony glycol in steps (1) and (2).

[0083] In this comparative example, the molar ratio of adipic acid in step (2) to lithium isophthalic acid-5-sulfonate in step (1) is 0.5:1.

[0084] In this comparative example, the amount of antioxidant used was 0.1 wt% of the total mass of lithium isophthalic acid-5-sulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0085] Product performance: The sulfonate polyester polyol was tested and found to have a hydroxyl value of 68 mg KOH / g, an acid value of 3.9 mg KOH / g, an alpha value of 60, a PDI of 1.6, and a water solubility of 50%. The product was diluted to 50% with ethyl acetate as the polyol component. 10% (by weight) of Covestro XP 2655 curing agent was added to the polyol, and after thorough mixing, a 10 μm thick dry film was coated onto PET and cured at 50°C for 48 hours. The surface resistivity was measured to be 3.24 × 10⁻⁶. 10 Ω·cm. Low-temperature bending performance (-30℃, 2mm standard shaft, 180° bend). o ): Slight crack.

[0086] As can be seen from this comparative example, even if the amount of adipic acid is reduced (the amount of triethylene glycol will also be reduced accordingly) without the presence of lithium 2-(diethanolamine)ethanesulfonate, the resistance still cannot be reduced.

[0087] When the molar ratio of lithium isophthalic acid-5-sulfonate, ethylene glycol, and triethylene glycol is 1:5:1.5, and the molar ratio of adipic acid in step (2) to lithium isophthalic acid-5-sulfonate in step (1) is 1:1, the surface resistivity of the resulting sulfonate polyester polyol is 2.44 × 10⁻⁶. 11 Ω·cm. Low-temperature bending performance (-30℃, 2mm standard shaft, 180° bend): slight cracking. Solubility in water is 36%.

[0088] Example 4 A sulfonate polyester polyol of the present invention is prepared by esterification-polymerization reaction using isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, aliphatic dicarboxylic acid, ethylene glycol, and triethylene glycol as reactants. The chemical structure of the sulfonate polyester polyol contains a sulfonated aromatic ring unit as shown in formula (I) and a tertiary amine-sulfonic acid side chain as shown in formula (II).

[0089] In formula (Ⅰ), M1 is Na, and in formula (Ⅱ), M2 is Li.

[0090] In this embodiment, the hydroxyl value of the sulfonate polyester polyol is 58 mg KOH / g, the acid value is 2.2 mg KOH / g, and the hue alpha value is 29.

[0091] In this embodiment, isophthalic acid-5-sulfonate is sodium isophthalic acid-5-sulfonate.

[0092] In this embodiment, 2-(diethanolamine)ethanesulfonate is lithium 2-(diethanolamine)ethanesulfonate.

[0093] The preparation process of lithium 2-(diethanolamino)ethanesulfonate is as follows: 2-(diethanolamino)ethanesulfonic acid and lithium hydroxide are added to water at a molar ratio of 1:1 for neutralization reaction. After the reaction, the water is evaporated and dried under vacuum at 240℃ for 3 hours to obtain lithium 2-(diethanolamino)ethanesulfonate.

[0094] In this embodiment, the aliphatic dicarboxylic acid is adipic acid.

[0095] A method for preparing sulfonate polyester polyol according to this embodiment includes the following steps: (1) Pre-esterification reaction: Sodium isophthalic acid-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and antimony glycol are added to the reaction vessel and pre-esterified at 190℃~200℃ for 3 hours under nitrogen protection to generate sulfonated diol intermediate. (2) Polycondensation reaction: The sulfonated diol intermediate, adipic acid and antioxidant triphenyl phosphite are mixed and reacted in two stages. The first reaction stage is esterification at atmospheric pressure at 180℃, and water is removed until the acid value is 9 mg KOH / g. In the second reaction stage, antimony glycol is added and the temperature is raised to 230℃-240℃ at 8-10℃ / h. At this temperature, a vacuum is drawn to -0.08MPa and polycondensation continues for 4 hours until the hydroxyl value is 58 mg KOH / g and the acid value is 2.2 mg KOH / g, to obtain the crude product of sulfonate polyester polyol.

[0096] (3) Post-treatment: The crude product of sulfonate polyester polyol was purified by dissolution-precipitation using a mixture of acetone and water. The mass ratio of acetone to water in the mixture was 1:1. After dehydration under reduced pressure, sulfonate polyester polyol was obtained with a hue Alpha value of 29.

[0097] In this embodiment, the sum of the masses of antimony glycolate in step (1) and antimony glycolate in step (2) is 0.1 wt% of the total mass of sodium isophthalate-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0098] In step (1) of this embodiment, the molar ratio of sodium isophthalate-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, and triethylene glycol is 1:0.5:5:1.5, and the mass of antimony glycol is 60% of the total mass of antimony glycol in steps (1) and (2).

[0099] In this embodiment, the molar ratio of adipic acid in step (2) to sodium isophthalic acid-5-sulfonate in step (1) is 1:1, and the amount of antimony glycolate added in step (2) is 40% of the total mass of antimony glycolate in steps (1) and (2).

[0100] In this embodiment, the amount of antioxidant used is 0.1 wt% of the total mass of sodium isophthalate-5-sulfonate, lithium 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and adipic acid.

[0101] Product performance: The sulfonate polyester polyol was tested and found to have a hydroxyl value of 58 mg KOH / g, an acid value of 2.2 mg KOH / g, an alpha value of 29, a PDI of <1.3, and was miscible with water. The product was diluted to 50% with ethyl acetate as the polyol component. 10% (by weight) of Covestro XP 2655 curing agent was added to the polyol, and after thorough mixing, a 10 μm thick dry film was coated onto PET and cured at 50°C for 48 hours. The surface resistivity was measured to be 3.72 × 10⁻⁶. 8 Ω·cm, Low-temperature bending performance (-30℃, 2mm standard shaft, 180° bend): No cracks.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A sulfonate polyester polyol, characterized in that, The sulfonate polyester polyol is prepared by reacting isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, aliphatic dicarboxylic acid, ethylene glycol, and triethylene glycol. The chemical structure of the sulfonate polyester polyol contains a sulfonated aromatic ring unit as shown in formula (I) and a tertiary amine-sulfonic acid side chain as shown in formula (II). In formula (I), M1 is an alkali metal; in formula (II), M2 is an alkali metal. The sulfonate polyester polyol has a hydroxyl value of 30 mg KOH / g to 90 mg KOH / g, an acid value of ≤3 mg KOH / g, and a hue alpha value of <30.

2. The sulfonate polyester polyol according to claim 1, characterized in that, The isophthalic acid-5-sulfonate includes one or more of lithium isophthalic acid-5-sulfonate, lithium dimethyl isophthalate-5-sulfonate, sodium dimethyl isophthalate-5-sulfonate, and sodium isophthalic acid-5-sulfonate. And / or, in formula (I), M1 is Li or Na, and in formula (II), M2 is Li or Na; And / or, the aliphatic dicarboxylic acid includes one or more of adipic acid, sebacic acid, and succinic acid.

3. The sulfonate polyester polyol according to claim 1, characterized in that, The 2-(diethanolamino)ethanesulfonate includes lithium 2-(diethanolamino)ethanesulfonate and / or sodium 2-(diethanolamino)ethanesulfonate.

4. The sulfonate polyester polyol according to claim 3, characterized in that, The preparation process of lithium 2-(diethanolamino)ethanesulfonate is as follows: 2-(diethanolamino)ethanesulfonic acid and lithium hydroxide are added to water for neutralization reaction, and after drying, lithium 2-(diethanolamino)ethanesulfonate is obtained; wherein, the molar ratio of 2-(diethanolamino)ethanesulfonic acid to lithium hydroxide is 1:1, and the drying includes first evaporating the water, and then vacuum drying at 240℃~260℃ for 3h~5h.

5. The sulfonate polyester polyol according to any one of claims 1 to 4, characterized in that, The surface resistance of the polymer film obtained by curing the sulfonate polyester polyol is <10×10⁻⁶. 8 Ω·cm, no cracks when bent at -30℃, the sulfonate polyester polyol is miscible with water.

6. A method for preparing a sulfonate polyester polyol according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Pre-esterification reaction: 5-sulfonate isophthalic acid, 2-(diethanolamine) ethanesulfonate, ethylene glycol, triethylene glycol and catalyst are added to the reaction vessel and heated to 180℃~200℃ under nitrogen protection to carry out the pre-esterification reaction and generate sulfonated diol intermediate. (2) Polycondensation reaction: The sulfonated diol intermediate, aliphatic diacid and antioxidant are mixed and the reaction is carried out in two stages. The first reaction stage is to carry out atmospheric pressure esterification at 160℃~190℃, remove water until the acid value is ≤10mg KOH / g, and generate polyester oligomer. The second reaction stage is to add catalyst, then raise the temperature to 220℃~240℃, and then vacuum at this temperature to polycondense until the hydroxyl value is 30mg KOH / g~90mg KOH / g and the acid value is ≤3mg KOH / g, to obtain the crude product of sulfonate polyester polyol. (3) Post-processing: The crude product of the sulfonate polyester polyol is dissolved and precipitated for purification, and then dehydrated under reduced pressure to obtain the sulfonate polyester polyol with a color Alpha value <30.

7. The method for preparing sulfonate polyester polyol according to claim 6, characterized in that, The sum of the masses of the catalyst in step (1) and the catalyst in step (2) is 0.08 wt% to 0.1 wt% of the total mass of the isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and aliphatic dicarboxylic acid.

8. The method for preparing sulfonate polyester polyol according to claim 6, characterized in that, In step (1), the molar ratio of isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, ethylene glycol, and triethylene glycol is 1:0.2 to 0.5:5:1 to 2, and the amount of catalyst added is 60% to 70% of the total mass of the catalyst in steps (1) and (2). The molar ratio of the aliphatic dicarboxylic acid in step (2) to the isophthalic acid-5-sulfonate in step (1) is 0.5 to 1:1, and the amount of catalyst added in step (2) is 30% to 40% of the total mass of the catalyst in steps (1) and (2).

9. The method for preparing sulfonate polyester polyols according to any one of claims 6 to 8, characterized in that, The catalyst in steps (1) and (2) is antimony glycolate; in step (2), the antioxidant is triphenyl phosphite, and the amount of antioxidant used in step (2) is 0.05wt% to 0.1wt% of the total mass of isophthalic acid-5-sulfonate, 2-(diethanolamine)ethanesulfonate, ethylene glycol, triethylene glycol and aliphatic dicarboxylic acid.

10. The method for preparing sulfonate polyester polyols according to any one of claims 6 to 8, characterized in that, In step (1), the esterification reaction takes 3 to 5 hours; in step (2), the heating rate in the second reaction stage is 8°C / h to 10°C / h, and the vacuum is applied to 0 to -0.1 MPa; in step (3), the solvent used for dissolution-precipitation purification is a mixture of acetone and water, and the mass ratio of acetone to water in the mixture is 1:0.8 to 1.

Images