Isornic acid-tetraepoxy cyclosiloxane silicone prepolymer modified polyester polyol, and preparation method and application thereof

Abstract

The present application provides a kind of isonitric acid-tetraepoxy cyclosiloxane organic silicon prepolymer modified polyester polyol and its preparation method and application, the isonitric acid-tetraepoxy cyclosiloxane organic silicon prepolymer modified polyester polyol includes the following raw materials: dibasic carboxylic acid, dihydric alcohol, small molecule double hydroxyl monomer with isonitric acid structure and tetraepoxy cyclosiloxane organic silicon prepolymer.The tetraepoxy cyclosiloxane organic silicon prepolymer in the present application occurs multi-point ring-opening reaction with polyester system under catalyst, introduces silicon prepolymer to improve tensile strength, hydrolysis resistance, high temperature resistance and stain resistance performance.Isonitric acid branched chain is introduced to reduce the crystallinity of polyester polyol, increase flexible segment, thereby improve elongation at break and hydrolysis resistance performance;Pre-esterification ensures that isonitric acid is completely reacted, the main reaction synchronously introduces prepolymer, makes it uniformly distributed, modification efficiency is high, process is simple, and product can be directly used for artificial leather polyurethane resin.

Description

Technical Field

[0001] This invention relates to an isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer modified polyester polyol, its preparation method and application, belonging to the field of polymer compound preparation technology. Background Technology

[0002] Polyurethane materials are polymerized from isocyanates and polyols. Due to their excellent mechanical properties, high mechanical strength, good resilience, and superior toughness, they are widely used in various aspects of national economy and people's livelihood, such as construction, leather, and textiles. There are many types of polyols used in the synthesis of polyurethane, including polyester, polyether, polycaprolactone, polycarbonate, and polypropylene carbonate polyols. Polyester polyols are generally produced by the condensation polymerization of dicarboxylic acids and diols. Due to their wide availability, low price, and excellent performance, they are widely used in polyurethane applications.

[0003] Polyurethane synthetic leather is currently one of the ideal materials to replace natural leather. It is mainly composed of a base fabric (knitted, woven, non-woven, etc.) and polyurethane materials, and is widely used in the production of synthetic leather products such as shoes, bags, clothing, sofas, automobiles, and balls. Polyurethane synthetic leather uses polyester polyols, which are classified into aliphatic and aromatic categories based on whether they contain benzene rings. Commonly used acids in aliphatic categories include succinic acid and adipic acid, while commonly used acids in aromatic categories include terephthalic acid, phthalic acid, and phthalic anhydride.

[0004] Because polyester polyols (polyesters) contain ester bonds, these bonds are prone to hydrolysis under high temperature, high humidity, alkaline, and acidic environments. This results in a shorter lifespan for polyester-based polyurethane artificial leather materials. For example, some sofas, clothing, and bags are easily hydrolyzed and crumbled after a period of use. Aliphatic polyester polyurethane artificial leather materials generally have poor high-temperature resistance, especially when pressed at temperatures above 200℃. The material is prone to scorching and discoloration. For instance, some suede embossed artificial leather products will turn grayish and exhibit significant color differences when embossing temperatures exceed 200℃, while the embossed patterns are unclear when embossing temperatures below 200℃. Aromatic polyester polyurethane materials have slightly better temperature resistance than aliphatic types, but they are harder, have poor cold resistance, and are prone to brittleness at low temperatures. Furthermore, the presence of benzene rings in their molecular structure makes them susceptible to oxidation and yellowing under high-temperature conditions. Due to their high polarity and surface tension, polyester polyurethane artificial leather materials have poor resistance to stains and graffiti. Oil stains, sweat stains, and pigments are difficult to wipe off and clean. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer modified polyester polyol, its preparation method, and its application.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides an isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer modified polyester polyol, wherein the modified polyester polyol is obtained by copolymerization reaction of raw materials comprising the following components: dicarboxylic acid, diol, small molecule dihydroxy monomer containing isononanoic acid structure and tetracyclooxysiloxane organosilicon prepolymer.

[0007] In this invention, the multiple epoxy groups of the tetracyclic cyclosiloxane organosilicon prepolymer can undergo multi-point ring-opening addition with the carboxyl or hydroxyl groups in the polyester system to form Si-OC covalent bonds, which helps to suppress phase separation and improve tensile strength, heat resistance, hydrolysis resistance, and stain resistance. The introduction of small molecule dihydroxy monomers containing isononanoic acid structure into the C9 branch chain helps to reduce the crystallinity of polyester segments, reduce ester bond content, and improve elastic elongation and hydrolysis resistance.

[0008] Preferably, the small molecule dihydroxy monomer containing isononanoic acid structure is a dihydroxy compound formed by monoesterification of trimethylolpropane and branched C9 carboxylic acid. Furthermore, the branched C9 carboxylic acid is isononanoic acid. Isononanoic acid undergoes a monoesterification reaction with trimethylolpropane at a molar ratio of 1:1.05-1.1. Only one of the three hydroxyl groups of trimethylolpropane undergoes esterification with the carboxyl group of isononanoic acid, retaining two free hydroxyl groups. The resulting dihydroxy compound can participate in the polycondensation reaction of the polyester backbone.

[0009] Isononanoic acid undergoes an esterification reaction with a small molecule alcohol containing three hydroxyl groups. The reaction equation is as follows, where R is a small molecule organic monomer.

[0010]

[0011] Preferably, the dicarboxylic acid is adipic acid; the diol is selected from at least one of ethylene glycol, 2-methyl-1,3-propanediol, neopentyl glycol, and 1,4-butanediol; by using two or more diols in combination, the chain segment structure and physical properties of the polyester polyol can be further controlled.

[0012] Preferably, the modified polyester polyol has a hydroxyl value of 50-65 mgKOH / g and an acid value of ≤1.0 mgKOH / g.

[0013] A hydroxyl value within the above range ensures that the product has moderate reactivity with isocyanate, and an acid value below 1.0 mg KOH / g avoids poisoning of the polyurethane synthesis catalyst.

[0014] Secondly, the present invention provides a method for preparing isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer modified polyester polyol, comprising the following steps: Step (1) under nitrogen protection, isononanoic acid is subjected to a pre-esterification reaction with trimethylolpropane to obtain the small molecule dihydroxy monomer containing isononanoic acid structure; Step (2) under nitrogen protection and in the presence of a catalyst, the small molecule dihydroxy monomer containing isononanoic acid structure is subjected to a copolymerization reaction with dicarboxylic acid, diol, and tetracyclooxysiloxane organosilicon prepolymer to obtain the modified polyester polyol.

[0015] The structure of the modified polyester polyol is shown in formula (I): Formula (I); Where R is (CH2). a , a≥2; a, l, m, n, r are all positive integers.

[0016] In the two-step process described above, the pre-esterification step helps to improve the conversion rate of isononanoic acid, and the resulting small molecule dihydroxy monomer has a clear structure. In the main reaction stage, after the polyester chain has initially grown, the organosilicon prepolymer is introduced, which is conducive to its uniform distribution in the system, avoids silicon chain agglomeration, makes the acid value and hydroxyl value easier to control, and has the best overall performance.

[0017] Preferably, in step (1), the molar ratio of isononanoic acid to trimethylolpropane is 1:1.05-1.1.

[0018] The temperatures for the pre-esterification reaction include 155-160℃ and 220-230℃; During the pre-esterification reaction, continuous dehydration occurred. The esterification reaction was completed when the acid value was ≤0.5 mgKOH / g, the hydroxyl value was between 407-411 mgKOH / g, and the moisture content was ≤0.03%. The yield of the small molecule dihydroxy monomer was over 92%.

[0019] Preferably, in step (2), the amounts of each component are: 100 parts by weight of dicarboxylic acid, 40-70 parts by weight of diol, 5-20 parts by weight of small molecule dihydroxy monomer containing isononanoic acid structure, and 1-5 parts by weight of tetracyclic cyclosiloxane organosilicon prepolymer. The catalyst is tetrabutyl titanate; The dosage of tetrabutyl titanate is 0.001-0.002% of the total material mass. The dosage is small, the side reactions are few, and the product has a light color.

[0020] Preferably, in step (2), the temperature of the copolymerization reaction includes 155-160℃, 180℃ and 230-235℃; the time of the copolymerization reaction is 15-20 h.

[0021] A gradient heating process is adopted. Initial polycondensation is carried out at 155-160℃. When the acid value drops to 45-55 mgKOH / g, tetracyclic cyclosiloxane organosilicon prepolymer is added. The temperature is then raised to 180℃ for further polycondensation. Finally, the temperature is raised to 230-235℃ to complete deep polycondensation under vacuum conditions.

[0022] Preferably, the modified polyester polyol obtained in step (2) has an acid value ≤0.7 mgKOH / g, a hydroxyl value of 53-59 mgKOH / g, and a moisture content ≤0.03%. Controlling the moisture content to below 0.03% can meet the strict requirements of polyurethane synthesis on the moisture content of raw materials, avoid side reactions with isocyanates to generate urea groups, which would cause the product to become hard and brittle and reduce its performance.

[0023] Thirdly, the present invention provides the application of isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer modified polyester polyol in the preparation of polyurethane materials, wherein the polyurethane material is a polyurethane resin for artificial leather.

[0024] The modified polyester polyols mentioned above are used as soft segment components in the preparation of polyurethane resins for artificial leather. The resulting artificial leather has improved tensile strength, elongation at break, high temperature resistance, hydrolysis resistance and stain resistance compared with ordinary polyester polyol products. It can replace existing polyester polyols in related production without significant adjustments to the formulation system.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The tetracyclic cyclosiloxane organosilicon prepolymer, containing polyepoxy groups, undergoes a multi-site ring-opening reaction with the carboxyl / hydroxyl groups of the polyester system under the action of a catalyst, thereby improving tensile strength, high-temperature resistance, hydrolysis resistance, and stain resistance. The introduction of isononanoic acid branches reduces the crystallinity of the polyester polyol, increases flexible segments, reduces ester bond content, and improves elongation at break and hydrolysis resistance, overcoming the shortcomings of polyester polyols in high-temperature resistance, hydrolysis resistance, and stain resistance. The two-step preparation process involves pre-esterification to ensure complete reaction of isononanoic acid, and the introduction of the prepolymer during the main reaction stage, while the polyester chain grows, ensures uniform distribution. This method boasts high modification efficiency, a simple process, and the product can be directly used in polyurethane resins for artificial leather. Attached Figure Description

[0026] Figure 1 Infrared spectra of polyester polyols modified from small molecule dihydroxy monomers containing isononanoic acid structure and isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer. Detailed Implementation

[0027] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0028] Unless otherwise specified, all raw materials used in the following examples are commercially available products.

[0029] Isononanoic acid was purchased from Wanhua Chemical (Yantai) Sales Co., Ltd., model number INA, purity ≥99.0%; trimethylolpropane was purchased from Wanhua Chemical (Yantai) Sales Co., Ltd., model number TMP; adipic acid was purchased from Shandong Hualu Hengsheng Chemical Co., Ltd., model number AA, purity ≥99.7%; ethylene glycol was purchased from Anhui Haoyuan Chemical Group Co., Ltd., model number EG; 2-methyl-1,3-propanediol was purchased from Dalian Chemical (Jiangsu) Co., Ltd., model number MPO; tetraepoxycyclosiloxane organosilicon prepolymer was from Guangzhou Silok New Materials Co., Ltd., model number Silok3590F4.

[0030] The hydroxyl value was determined by the acetylation method. The sample was dissolved in a pyridine-acetic anhydride mixed solution and refluxed at 95-100℃ for 1 h. The solution was then titrated with potassium hydroxide standard solution using phenolphthalein as an indicator. The result was expressed as mgKOH / g.

[0031] The acid value was determined according to the method specified in HG / T 2708. The sample was dissolved in a toluene-ethanol mixed solvent and titrated to the endpoint with a potassium hydroxide-ethanol standard solution. The result was expressed as mgKOH / g.

[0032] Moisture content was determined by the Karl Fischer method. Approximately 1 g of the sample was dissolved in anhydrous methanol and titrated with Karl Fischer reagent. The result was expressed as a mass fraction (%).

[0033] Preparation Example Preparation method of small molecule dihydroxy monomer (TA-1) containing isononanoic acid structure: By weight percentage, 52.9% isononanoic acid and 47.1% trimethylolpropane (theoretical molar ratio 1:1.05) were added to a reactor equipped with mechanical stirring and a nitrogen inlet. Under nitrogen protection, the temperature was first raised to 155-160℃ and held constant for 2-3 hours, then raised to 220-230℃ and held constant for another 2-3 hours. The reaction was confirmed to be complete by sampling and monitoring the acid value (≤0.5 mgKOH / g), hydroxyl value (407-411 mgKOH / g), and moisture content (≤0.03%), yielding a small-molecule dihydroxy monomer containing the isononanoic acid structure, denoted as TA-1.

[0034] Preparation method of isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer modified polyester polyol:

[0035] According to the weight percentages in the table, adipic acid, ethylene glycol, 2-methyl-1,3-propanediol, and TA-1 are added to a reactor equipped with mechanical stirring and a nitrogen inlet. Under nitrogen protection, the mixture is heated to 155-160℃ and held at that temperature for 2-3 hours for dehydration. When the acid value reaches 45-55 mgKOH / g, tetracyclic cyclosiloxane organosilicon prepolymer Silok3590F4 is added, and the temperature is further increased to 180℃ and held at that temperature for 1-2 hours. Then, the temperature is increased to 230-235℃, and 0.001%-0.003% tetrabutyl titanate is added. The reaction is maintained within this temperature range for 15-20 hours. Nitrogen is continuously introduced during the reaction to prevent oxidation of the polyol and to remove the water generated during the reaction. The desired polyester polyol is finally obtained, with the following specifications: acid value ≤ 0.7 mgKOH / g; hydroxyl value 53-59 mgKOH / g; moisture content ≤ 0.03%.

[0036] The small molecule dihydroxy monomer (TA-1) containing the isononanoic acid structure obtained in step (1) was characterized by infrared spectroscopy. The infrared spectrum of TA-1 is analyzed as follows: Figure 1 As shown: 900-400 cm -1 The region exhibits dense absorption peaks, indicating molecular skeleton bending vibrations and C / C and CO bond vibrations, reflecting the combined characteristics of the isononanoic acid branched structure and the trimethylolpropane skeleton; 1200-1100 cm⁻¹ -1 The presence of a strong absorption peak in the region, attributed to the asymmetric stretching vibration of the ester group COC, is the most recognizable fingerprint peak for ester compounds, confirming the presence of esterification products; 1735 cm⁻¹ -1 A sharp absorption peak appears nearby, which is due to the C=O stretching vibration of the ester carbonyl group (the free isononanoic acid carbonyl peak is located at 1710 cm⁻¹). -1 (The peaks are broad and sharp, with increased wavenumbers, confirming ester formation); 2950-2850 cm⁻¹ -1 The strong absorption peaks are due to the symmetric / asymmetric stretching vibrations of the -CH2- and -CH3 groups in the isononanoic acid and trimethylolpropane molecular chains; 3400 cm⁻¹ -1 A broad and strong absorption band appears nearby, indicating the stretching vibration of the remaining free hydroxyl groups after the reaction of trimethylolpropane. (1735 cm⁻¹) -1 The nearby strong ester carbonyl peak is at 1100 cm⁻¹ -1 The nearby COC peaks together prove that isononanoic acid and trimethylolpropane have successfully undergone esterification, retaining two free hydroxyl groups.

[0037] The modified polyester polyol obtained in step (2) was characterized by infrared spectroscopy. The infrared spectrum of the modified polyester polyol is as follows: 600-400 cm⁻¹ -1 The absorption peak is mainly due to the bending vibration of the C-C bonds in polyols; 800 cm⁻¹ -1The nearby absorption peaks are attributed to Si-C bond stretching vibrations; 1090-1020 cm⁻¹ -1 The absorption peaks are due to the stretching vibrations of the Si-O-Si bonds; 1250-1120 cm⁻¹ -1 The presence of multiple absorption peaks indicates the stretching vibration of COC; 1730 cm⁻¹ -1 A strong characteristic absorption peak appears nearby, indicating C=O stretching vibration; 2960 cm⁻¹ -1 It is an asymmetric stretching vibration of -CH3, 2870 cm⁻¹ -1 This is a -CH2- / -CH3 symmetric stretching vibration, and this set of peaks corresponds to the alkyl structure in the polyol molecule; 3600-3200 cm⁻¹ -1 The broad absorption peak is due to the OH stretching vibration of the terminal hydroxyl groups in the polyester polyol. Comprehensive analysis: 1730 cm⁻¹ -1 The nearby ester carbonyl peak and 1250 cm⁻¹ -1 The nearby COC peak confirms that adipic acid successfully underwent esterification with various small molecule alcohols, generating structurally complete polyester polyols; 1090 cm⁻¹ -1 The nearby Si-O-Si peak and 800 cm⁻¹ -1 The nearby Si-C peaks confirm that the tetraepoxycyclosiloxane organosilicon prepolymer has been successfully introduced into the polyester system; 2700-2500 cm⁻¹ -1 The absence of obvious absorption peaks in the region indicates that the free carboxyl groups in the system have basically reacted completely, and the esterification conversion rate is high.

[0038] Example 1 Add 1800 g of adipic acid, 540.21 g of ethylene glycol, 392.09 g of 2-methyl-1,3-propanediol, and 119.53 g of TA-1 to a reactor equipped with mechanical stirring and a nitrogen inlet. Under nitrogen protection, heat to 155-160℃ and hold at that temperature for 2-3 hours to dehydrate. When the acid value reaches 45-55 mgKOH / g, add 32.06 g of tetracyclic cyclosiloxane organosilicon prepolymer Silok3590F4. Continue heating to 180℃ and hold at that temperature for 1-2 hours. Then, heat to 230-235℃ and add 0.05 g of tetrabutyl titanate. Maintain this temperature range for 15-20 hours. Nitrogen gas was continuously introduced during the reaction to prevent the polyol from oxidizing and to remove the water generated in the reaction. The test results of the synthesized polyester polyol were as follows: acid value 0.35 mgKOH / g; hydroxyl value 56.2 mgKOH / g; and water content 0.0162%.

[0039] Example 2 Add 1800 g of adipic acid, 539.58 g of ethylene glycol, 391.63 g of 2-methyl-1,3-propanediol, and 119.39 g of TA-1 to a reactor equipped with mechanical stirring and a nitrogen inlet. Under nitrogen protection, heat to 155-160℃ and hold at that temperature for 2-3 hours to dehydrate. When the acid value reaches 45-55 mgKOH / g, add 49.64 g of tetracyclic cyclosiloxane organosilicon prepolymer Silok3590F4. Continue heating to 180℃ and hold at that temperature for 1-2 hours. Then, heat to 230-235℃ and add 0.05 g of tetrabutyl titanate. Maintain this temperature range for 15-20 hours. Nitrogen gas was continuously introduced during the reaction to prevent the polyol from oxidizing and to remove the water generated in the reaction. The test results of the synthesized polyester polyol were as follows: acid value 0.32 mgKOH / g; hydroxyl value 55.6 mgKOH / g; and water content 0.0192%.

[0040] Example 3 Add 1800 g of adipic acid, 525.04 g of ethylene glycol, 381.07 g of 2-methyl-1,3-propanediol, and 232.35 g of TA-1 to a reactor equipped with mechanical stirring and a nitrogen inlet. Under nitrogen protection, heat to 155-160℃ and hold at that temperature for 2-3 hours to dehydrate. When the acid value reaches 45-55 mgKOH / g, add 31.16 g of tetracyclic cyclosiloxane organosilicon prepolymer Silok3590F4. Continue heating to 180℃ and hold at that temperature for 1-2 hours. Then, heat to 230-235℃ and add 0.05 g of tetrabutyl titanate. Maintain this temperature range for 15-20 hours. Nitrogen gas was continuously introduced during the reaction to prevent the polyol from oxidizing and to remove the water generated in the reaction. The test results of the synthesized polyester polyol were as follows: acid value 0.28 mgKOH / g; hydroxyl value 56.3 mgKOH / g; and water content 0.0147%.

[0041] Example 4 Add 1800 g of adipic acid, 525.52 g of ethylene glycol, 380.68 g of 2-methyl-1,3-propanediol, and 232.11 g of TA-1 to a reactor equipped with mechanical stirring and a nitrogen inlet. Under nitrogen protection, heat to 155-160℃ and hold at that temperature for 2-3 hours to dehydrate. When the acid value reaches 45-55 mgKOH / g, add 46.7 g of tetracyclic cyclosiloxane organosilicon prepolymer Silok3590F4. Continue heating to 180℃ and hold at that temperature for 1-2 hours. Then, heat to 230-235℃ and add 0.05 g of tetrabutyl titanate. Maintain this temperature range for 15-20 hours. Nitrogen gas was continuously introduced during the reaction to prevent the polyol from oxidizing and to remove the water generated in the reaction. The test results of the synthesized polyester polyol were as follows: acid value 0.35 mgKOH / g; hydroxyl value 55.2 mgKOH / g; and water content 0.0167%.

[0042] Comparative Example 1 1800 g of adipic acid, 526.12 g of ethylene glycol, 381.86 g of 2-methyl-1,3-propanediol, and 232.82 g of TA-1 were added to a reactor equipped with mechanical stirring and a nitrogen inlet. Under nitrogen protection, the mixture was heated to 155-160℃ and held at this temperature for 2-3 hours to remove water. The temperature was then increased to 180℃ and held for 1 hour, followed by a further increase to 230-235℃. 0.05 g of tetrabutyl titanate was added, and the reaction was maintained within this temperature range for 15-20 hours. Nitrogen gas was continuously introduced during the reaction to prevent oxidation of the polyol and to remove the water generated during the reaction. The synthesized polyester polyol had the following characteristics: acid value 0.28 mgKOH / g; hydroxyl value 56.2 mgKOH / g; and moisture content 0.028%.

[0043] Comparative Example 2 1800 g of adipic acid, 556.19 g of ethylene glycol, and 403.76 g of 2-methyl-1,3-propanediol were added to a reactor equipped with mechanical stirring and a nitrogen inlet. The mixture was heated to 155-160℃ under nitrogen protection and held at this temperature for 2-3 hours to remove water. When the acid value reached 45-55 mgKOH / g, 33.02 g of tetracyclic cyclosiloxane organosilicon prepolymer Silok3590F4 was added, and the temperature was further increased to 180℃ and held for 1-2 hours. Subsequently, the temperature was increased to 230-235℃, and 0.05 g of tetrabutyl titanate was added. The reaction was maintained within this temperature range for 15-20 hours. Nitrogen gas was continuously purged during the reaction to prevent oxidation of the polyol and to remove the water generated during the reaction. The synthesized polyester polyol showed the following results: acid value 0.28 mgKOH / g; hydroxyl value 56.2 mgKOH / g; and water content 0.028%.

[0044] Comparative Example 3 1800 g of adipic acid, 557.51 g of ethylene glycol, and 404.64 g of 2-methyl-1,3-propanediol were added to a reactor equipped with a mechanical stirrer and a nitrogen inlet. Under nitrogen protection, the mixture was heated to 155-160℃ and held at this temperature for 2-3 hours to remove water. The temperature was then increased to 180℃ and held for 1 hour, followed by a further increase to 230-235℃. 0.05 g of tetrabutyl titanate was added, and the reaction was maintained within this temperature range for 15-20 hours. Nitrogen gas was continuously purged during the reaction to prevent oxidation of the polyol and to remove the water generated during the reaction. The synthesized polyester polyol had the following characteristics: acid value 0.36 mgKOH / g; hydroxyl value 56.8 mgKOH / g; and moisture content 0.021%.

[0045] Polyurethane resin for artificial leather was prepared by polymerizing the polyester polyols of Examples 1-4 and Comparative Examples 1-3 with isocyanate and chain extender in a reactor equipped with mechanical stirring and nitrogen inlet, by weight percentage. The raw material composition was: 32-33% polyester polyol, 14-15% 4,4-diphenylmethane diisocyanate, 3-4% ethylene glycol, and 49-51% DMF. Polymerization was carried out at 70-75°C to obtain a polyurethane resin with a solid content of 49%-51% and a viscosity of 60-90 Pa·s / 25°C.

[0046] The polyurethane resins prepared in Examples 1-4 and Comparative Examples 1-3 were used to prepare polyurethane films according to GB / T1040.3-2006 standard. Tensile strength and elongation at break were tested on the films. The stain resistance test method was as follows: 0.1 ml of olive oil was dropped onto the film surface, allowed to stand at room temperature for 1 h, and then wiped 10 times with a standard cleaning cloth applying 5 N pressure. Residual traces were rated according to a 5-level standard (Level 5: no residue, Level 4: slight residue, Level 3: moderate residue, Level 2: significant residue, Level 1: severe residue). The hydrolysis resistance test method was as follows: the film was immersed in a 10% NaOH solution and allowed to stand at 25°C for 24 h. Tensile strength and elongation at break retention were tested according to GB / T1040.3-2006 standard. The suede embossing effect test was conducted by weight: 100 g of the polyurethane resin prepared in Examples 1-4 and Comparative Examples 1-3, 100 g of DMF (N,N-dimethylformamide), and 6 g of brown pigment (Zhejiang Dali Industrial Co., Ltd.) were taken. g, after thorough mixing and vacuum degassing, a 0.15 mm thick coating is applied to the suede release paper (Wenzhou Shangcai New Material Co., Ltd.). The coating is then transferred to a sofa-specific wet-process base at 150℃ and embossed for 5 seconds at a roller temperature of 200℃ and a pressure of 10MPa. The color change of the leather surface before and after embossing is observed. The softening point is tested according to GB / T1633-2025 standard. The test results are shown in Table 1.

[0047] Table 1 Performance test results of samples from Examples 1-4 and Comparative Examples 1-3

[0048] Comparisons of Examples 1-4, Comparative Example 2, and Comparative Examples 1 and 3 (without silicone) show that polyester polyols containing tetracyclic cyclosiloxane silicone prepolymers in their molecular structure exhibit significantly improved tensile strength and temperature resistance (softening point). This is mainly because the introduction of silicone prepolymers causes the polyester polyol molecules to form a cross-linked network structure, increasing the intermolecular cohesive energy and thus improving mechanical properties and temperature resistance. Furthermore, silicon itself has higher temperature resistance than carbon, and the tetracyclic cyclosiloxane silicone prepolymer contains four six-carbon aliphatic rings, further enhancing the temperature resistance of the polyester polyol. The embossing effect shows that the softening points of the silicone-introduced polyester polyols are all greater than 200℃, and the color remains unchanged after high-temperature embossing; while Comparative Examples 1 and 3 (without silicone) show discoloration and graying after high-temperature embossing.

[0049] Comparisons between Examples 1-4 and Comparative Example 1 (containing only isononanoic acid), Comparative Example 2 (containing only organosilicon), and Unmodified Comparative Example 3 show that introducing isononanoic acid and organosilicon structures into polyester polyol molecules can enhance hydrolysis resistance. Isononanoic acid has a longer carbon chain than adipic acid and contains three methyl branches, resulting in greater steric hindrance. This effectively inhibits the hydrolytic activity of polyester polyols in hydrolytic environments while reducing the ester bond content, thereby improving hydrolysis resistance. The organosilicon structure has low surface tension and strong hydrophobicity, effectively preventing water molecules from damaging the ester bonds, thus also improving the hydrolysis resistance of polyester polyols.

[0050] A comparison of Examples 1-4 with Comparative Examples 1 and 3 (without silicone) shows that the polyester polyols with silicone structures exhibit superior stain resistance. This is mainly because the introduction of silicone elements forms a silicone protective film on the material surface. This film has low surface tension and good slip properties, making surface contaminants easier to clean.

[0051] The experimental results from the combined examples and comparative examples show that the simultaneous introduction of isononanoic acid and tetracyclooxysiloxane organosilicon prepolymer structures into the molecule significantly improves the hydrolysis resistance, high temperature resistance, softening point, and stain resistance of polyester polyols: tensile strength retention rate increases by 28.9-32.4%; elongation at break retention rate increases by 31.5-33.4%; softening point increases by 24-33℃; and stain resistance grade increases by 2-3 levels.

[0052] The applicant declares that the detailed technical solutions of this invention are illustrated through the above embodiments, but this invention is not limited to the above detailed technical solutions, that is, it does not mean that this invention must rely on the above detailed technical solutions to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection and disclosure scope of this invention.

Claims

1. A polyester polyol modified with isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer, characterized in that, The raw materials include: dicarboxylic acid, diol, small molecule dihydroxy monomers containing isononanoic acid structure, and tetracyclic cyclosiloxane organosilicon prepolymer; the preparation method of the isononanoic acid-tetracyclic cyclosiloxane organosilicon prepolymer modified polyester polyol includes the following steps: (1) Under nitrogen protection, isononanoic acid is pre-esterified with trimethylolpropane to prepare a small molecule dihydroxy monomer containing isononanoic acid structure; (2) Under nitrogen protection and in the presence of a catalyst, the small molecule dihydroxy monomer containing isononanoic acid structure is copolymerized with dicarboxylic acid, diol, tetraepoxysiloxane organosilicon prepolymer to obtain the modified polyester polyol.

2. The modified polyester polyol according to claim 1, characterized in that, The dicarboxylic acid is adipic acid; The diol is selected from at least one of ethylene glycol, 2-methyl-1,3-propanediol, neopentyl glycol, and 1,4-butanediol.

3. The modified polyester polyol according to claim 1, characterized in that, The modified polyester polyol has a hydroxyl value of 50-65 mgKOH / g and an acid value of ≤1.0 mgKOH / g.

4. The modified polyester polyol according to claim 1, characterized in that, In step (1), the molar ratio of isononanoic acid to trimethylolpropane is 1-1.05:1.

1.

5. The modified polyester polyol according to claim 1, characterized in that, In step (2), the amounts of each component are as follows: 100 parts by weight of dicarboxylic acid, 40-70 parts by weight of diol, 5-20 parts by weight of small molecule dihydroxy monomer containing isononanoic acid structure, and 1-5 parts by weight of tetracyclic cyclosiloxane organosilicon prepolymer; the catalyst is tetrabutyl titanate.

6. The modified polyester polyol according to claim 1, characterized in that, The copolymerization reaction in step (2) takes 15-20 h.

7. The modified polyester polyol according to claim 1, characterized in that, The modified polyester polyol obtained in step (2) has an acid value ≤0.7 mgKOH / g, a hydroxyl value of 53-59 mgKOH / g, and a moisture content ≤0.03%.

8. The application of the isononanoic acid-tetracyclooxysiloxane organosilicon prepolymer modified polyester polyol in the preparation of polyurethane materials as described in any one of claims 1-7, characterized in that, The polyurethane material is polyurethane resin for artificial leather.

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