A polyester polyol, a polyurethane resin, its preparation method and application

Abstract

This invention relates to a polyester polyol, a polyurethane resin, their preparation methods, and applications, belonging to the field of polyurethane gloves. The raw materials for preparing the polyester polyol, by weight percentage, include 20-30% m-aminobenzoic acid, 30-40% adipic acid, 1-4% o-methylhydroquinone, and 31-41% 1,4-cyclohexanediol. The raw materials for preparing the polyurethane resin, by weight percentage, include 9-18% of the above-mentioned polyester polyol, 0.5-8% 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester, 5-15% isocyanate, 0.5-4% chain extender, and 60-80% solvent A. This invention, through formulation design of the polyester polyol and polyurethane resin, produces polyurethane gloves that combine the advantages of anti-slip properties, breathability, and wear resistance, overcoming the shortcomings of traditional products that struggle to achieve both.

Description

Technical Field

[0001] This invention relates to the field of polyurethane glove technology, and more particularly to a polyester polyol, a polyurethane resin, its preparation method, and its application. Background Technology

[0002] The automotive repair industry involves a complex working environment, requiring frequent contact with oily media such as engine oil, lubricating oil, coolant, and fuel. Furthermore, the operation requires frequent gripping of metal parts, placing extremely high demands on the anti-slip, wear-resistant, oil-resistant, and breathable properties of protective gloves.

[0003] Currently available automotive repair gloves suffer from the following main problems: 1. Poor anti-slip properties, especially on oily metal surfaces, which can easily cause slippage when gripping tools or parts, posing a safety hazard. 2. Poor breathability, leading to sweaty, damp hands and a strong odor after prolonged wear. To improve the anti-slip properties of automotive repair gloves in oily environments, some manufacturers use adhesive dots (such as acrylic beads) or surface embossing. However, the adhesion between the adhesive layer and the glove substrate is weak, and it easily peels off after prolonged use. Furthermore, the adhesive area completely loses breathability, resulting in poor overall glove comfort. While embossing can improve dry-state anti-slip properties to some extent, its effectiveness drops drastically in oily environments when the pattern is filled with an oil film.

[0004] Polyurethane gloves have become an important branch of the protective glove industry due to their excellent abrasion resistance, good elasticity, and certain breathability. However, research on polyurethane gloves specifically designed for the automotive repair industry is still relatively limited, mainly focusing on waterproof and breathable properties (such as CN120645359A), hydrolysis resistance (such as CN121699379A), toughness, abrasion resistance, and environmental friendliness (such as CN121471468A). There is insufficient attention paid to the anti-slip performance of automotive repair gloves, and it is difficult to achieve a good balance between anti-slip properties, oil resistance, and breathability.

[0005] Therefore, how to develop a polyurethane glove that requires no further processing and has the advantages of being non-slip, breathable, and wear-resistant has become an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a polyester polyol, a polyurethane resin, a preparation method thereof, and its application. By designing a formulation for the polyester polyol and polyurethane resin, polyurethane gloves made from these materials possess the advantages of being non-slip, breathable, and wear-resistant, overcoming the shortcomings of traditional products that struggle to achieve a balance of performance.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a polyester polyol, wherein the raw materials for preparing the polyester polyol include, by mass percentage, 20-30% m-aminobenzoic acid, 30-40% adipic acid, 1-4% o-methylhydroquinone and 31-41% 1,4-cyclohexanediol.

[0008] Among them, 20-30% can be, for example, 20%, 22%, 24%, 25%, 26%, 28%, or 30%; 30-40% can be, for example, 30%, 32%, 34%, 36%, 38%, 39%, or 40%; 1-4% can be, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, or 4%; 31-41% can be, for example, 31%, 32%, 34%, 35%, 36%, 38%, 40%, or 41%.

[0009] This invention provides a novel method for preparing polyester polyols. By using m-aminobenzoic acid, adipic acid, o-methylhydroquinone, and 1,4-cyclohexanediol as raw materials, a rigid benzene ring, amide group, and cyclohexyl group are simultaneously introduced into the molecular structure of the polyester polyol, laying the foundation for the excellent properties of the subsequently prepared polyurethane resin. Specifically, m-aminobenzoic acid provides both amide groups and a meta-rigid benzene ring. The rigid benzene ring improves the compactness of the molecular chain, constructing a tightly cross-linked network that effectively blocks oil penetration and inhibits resin swelling, providing structural support for the wear resistance of the polyurethane resin. The meta-structure causes a certain degree of "knotting" or "bending" of the molecular chain. This imperfect linear structure guides the formation of microphase separation in the polyurethane, improving air permeability. The amide group strengthens intermolecular hydrogen bonding and cohesive strength, while simultaneously forming stable anti-slip resistance at the oil interface, directly imparting the polyurethane resin with... The excellent anti-slip properties of the resin prevent slippage due to contact with oil during use, and together they construct a polyester polyol basic framework with an ideal microstructure: moderate rigidity (ensuring that the breathable channels do not collapse), moderate polarity (ensuring anti-slip under oil), and the ability to spontaneously form nanoscale soft and hard segment partitions; 1,4-cyclohexanediol provides a cyclohexane structure, giving the soft segments of the polyurethane resin moderate rigidity and promoting the formation of a good microphase separation structure in the system. This microphase separation structure can form tiny breathable channels while ensuring the mechanical properties of the resin, so that the prepared polyurethane resin also has breathable properties.

[0010] Preferably, the molar ratio of hydroxyl to carboxyl groups in the raw materials for preparing the polyester polyol is (1.15-1.22):1, for example, it can be 1.15:1, 1.16:1, 1.17:1, 1.18:1, 1.19:1, 1.2:1, 1.21:1 or 1.22:1, etc.

[0011] Preferably, the weight-average molecular weight of the polyester polyol is 3600-4400 g / mol, for example, it can be 3600 g / mol, 3800 g / mol, 4000 g / mol, 4200 g / mol or 4400 g / mol.

[0012] The weight-average molecular weight is calculated based on the acid value and hydroxyl value of the obtained polyester polyol.

[0013] Preferably, the hydroxyl value of the polyester polyol is 25-27 mgKOH / g, for example, it can be 25 mgKOH / g, 25.5 mgKOH / g, 26 mgKOH / g, 26.5 mgKOH / g or 27 mgKOH / g, etc.

[0014] The hydroxyl value was obtained by titration according to the HG / T 2709-2022 standard.

[0015] This invention limits the amount of each raw material used in the preparation of polyester polyol, so that the molar ratio of hydroxyl to carboxyl groups in the raw materials is (1.15-1.22):1, to ensure that the final product is hydroxyl-terminated, and controls the molecular weight of polyester polyol between 3600-4400 g / mol, so that the polyurethane resin subsequently prepared can form ideal microphase separation in this system, while taking into account both air permeability and strength.

[0016] Preferably, the acid value of the polyester polyol is <0.5 mgKOH / g, for example, it can be 0.1 mgKOH / g, 0.2 mgKOH / g, 0.3 mgKOH / g or 0.4 mgKOH / g, etc.

[0017] The acid value was obtained by titration according to the HG / T 2708-1995 standard.

[0018] Preferably, based on the mass percentage of the raw materials for preparing the polyester polyol being 100%, the raw materials for preparing the polyester polyol further include 0.005-0.1% antioxidant A and / or 0.006-0.1% catalyst.

[0019] Among them, 0.005-0.1% can be, for example, 0.005%, 0.008%, 0.01%, 0.06%, 0.09%, or 0.1%; 0.006-0.1% can be, for example, 0.006%, 0.009%, 0.04%, 0.08%, or 0.1%.

[0020] Preferably, antioxidant A includes phosphate ester antioxidants.

[0021] Preferably, the catalyst comprises any one or a combination of at least two of tetrabutyl titanate, tetraisopropyl titanate, stannous octoate, or dibutyltin dilaurate.

[0022] In a second aspect, the present invention provides a method for preparing a polyester polyol as described in the first aspect, the method comprising the following steps: The polyester polyol is obtained by mixing amino-substituted m-aminobenzoic acid, adipic acid, o-methylhydroquinone and 1,4-cyclohexanediol, followed by polycondensation and esterification reactions.

[0023] Preferably, the mixing further includes mixing with antioxidant A.

[0024] Preferably, the temperature of the polycondensation reaction is 140-150℃, for example, 140℃, 142℃, 144℃, 145℃, 146℃, 148℃ or 150℃, and the time is 4-7 h, for example, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h or 7 h.

[0025] Preferably, the polycondensation reaction is carried out in an inert gas atmosphere.

[0026] Preferably, the inert gas includes nitrogen.

[0027] Preferably, the flow rate of the inert gas is 0.3-0.6 L / min, for example, it can be 0.3 L / min, 0.4 L / min, 0.5 L / min or 0.6 L / min, etc.

[0028] Preferably, the temperature of the esterification reaction is 220-230°C, for example, 220°C, 222°C, 225°C, 228°C or 230°C.

[0029] Preferably, the esterification reaction comprises first reacting at 220-230°C (e.g., 220°C, 222°C, 225°C, 228°C, or 230°C, etc.) for 2-4 hours (e.g., 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours, etc.), then reacting at 220-230°C (e.g., 220°C, 222°C, 225°C, 228°C, or 230°C, etc.), under vacuum conditions and in the presence of an optional catalyst, until the acid value of the reaction system is <0.5 mgKOH / g (e.g., 0.1 mgKOH / g, 0.2 mgKOH / g, 0.3 mgKOH / g, or 0.4 mgKOH / g, etc.) and the hydroxyl value is 25-27 mgKOH / g (e.g., 25 mgKOH / g, 25.5 mgKOH / g, 26 mgKOH / g, 26.5 mgKOH / g, or 27 mgKOH / g, etc.). The polyester polyol was obtained by (mgKOH / g, etc.).

[0030] Preferably, the vacuum degree of the vacuum condition is -0.01 to -0.1 MPa, for example, it can be -0.01 MPa, -0.02 MPa, -0.04 MPa, -0.05 MPa, -0.06 MPa, -0.08 MPa or -0.1 MPa, etc.

[0031] Thirdly, the present invention provides a polyurethane resin, wherein the raw materials for preparing the polyurethane resin include, by mass percentage, 9-18% polyester polyol as described in the first aspect, 0.5-8% 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester, 5-15% isocyanate, 0.5-4% chain extender, and 60-80% solvent A.

[0032] Among them, 9-18% can be, for example, 9%, 10%, 12%, 14%, 15%, 16%, or 18%; 0.5-8% can be, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, or 8%; 5-15% can be, for example, 5%, 6%, 8%, 10%, 12%, 14%, or 15%; 0.5-4% can be, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, or 4%; 60-80% can be, for example, 60%, 65%, 70%, 75%, or 80%.

[0033] This invention utilizes a polyester polyol containing rigid benzene rings, amide groups, and cyclohexane structures to copolymerize with 3-hydroxy-2,2-dimethylpropionic acid (HPN) to prepare polyurethane resin. The synergistic effect of the two types of polyols can effectively control the ratio and compatibility of the soft and hard segments in the polyurethane system, balancing the rigidity and flexibility of the resin. At the same time, relying on the rigid benzene rings, amide groups, and cyclohexane structures in the polyester polyol and the structural specificity of 3-hydroxy-2,2-dimethylpropionic acid (HPN), the microphase separation effect of the system is optimized. As a result, the prepared polyurethane product has excellent wear resistance, anti-slip properties, and breathability, making it suitable for the complex working conditions in the automotive repair field.

[0034] This invention utilizes 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester, which possesses a branched structure (two neopentyl units) and ester bonds. This branched structure effectively breaks down the aggregation tendency of hard segments, preventing them from agglomerating into large, disordered hard regions, thereby ensuring uniform and fine hard segment micro-region sizes. This plays a crucial role in precisely controlling the compatibility and microphase separation scale. Furthermore, in polyurethane synthesis, the hard segments (4,4-diphenylmethane diisocyanate containing benzene rings) and soft segments (the polyester polyol provided in the first aspect) have significant polarity differences, easily leading to macroscopic phase separation and poor material performance. 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester is compatible with both hard and soft segments at one end, acting like "tiny rivets" to anchor the hard and soft segments together, forming a nanoscale, uniform microphase separation. This nanoscale separation ensures both physical cross-linking points (strength, anti-slip properties) and creates continuous nanopores (breathability).

[0035] Preferably, the isocyanate comprises 4,4-diphenylmethane diisocyanate.

[0036] Preferably, the chain extender comprises ethylene glycol and / or 1,4-butanediol.

[0037] Preferably, solvent A comprises N,N-dimethylformamide.

[0038] Preferably, based on the mass percentage of the raw materials for preparing the polyurethane resin being 100%, the raw materials for preparing the polyurethane resin further include any one or a combination of at least two of the following: antioxidant B 0.001-0.03%, phosphoric acid 0.001-0.01%, chain terminator 0.01-0.05%, or anti-tackifying agent 0.01-0.05%.

[0039] Among them, 0.001-0.03% can be, for example, 0.001%, 0.005%, 0.01%, 0.015%, 0.02%, 0.025%, or 0.03%, etc.; 0.001-0.01% can be, for example, 0.001%, 0.002%, 0.004%, 0.005%, 0.006%, 0.008%, or 0.01%, etc.; 0.01-0.05% can be, for example, 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, or 0.05%, etc.

[0040] Preferably, antioxidant B includes phosphate ester antioxidants.

[0041] Preferably, the chain terminator comprises methanol.

[0042] Preferably, the anti-tack and anti-blocking agent includes malic acid.

[0043] Fourthly, the present invention provides a method for preparing a polyurethane resin as described in the third aspect, the method comprising the following steps: (1) The polyester polyol as described in the first aspect, 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester, optional antioxidant B, optional phosphoric acid, a portion of isocyanate and a portion of solvent A are mixed and reacted. (2) Add a portion of solvent A, chain extender and another portion of isocyanate to the reaction system obtained in step (1) and carry out the reaction; (3) Add the remaining solvent A to the reaction system obtained in step (2), and then add an optional chain terminator and an optional anti-tack agent to obtain the polyurethane resin.

[0044] The polyurethane resin preparation method provided by this invention employs a two-step polymerization process. First, polyester polyol, 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester, and a portion of isocyanate undergo a short-term prepolymerization reaction (R value during prepolymerization is 0.5-0.9) to prepare a polyurethane prepolymer. Then, another portion of isocyanate and a chain extender are added to undergo a chain extension reaction. By precisely controlling the ratio of hard and soft segments, microphase separation is achieved: the hard segment microregions act as physical crosslinking points, imparting strength and wear resistance; the continuous soft segment microregions form nanoscale free volume channels, allowing water vapor molecules to pass through while blocking water droplets, achieving waterproof and breathable properties. This avoids the polyurethane prepolymer having an excessively high molecular weight, which would lead to uneven mixing of hard and soft segments in the final polyurethane resin, excessively large and disordered distribution of hard segment microregions, thus affecting microphase separation.

[0045] Preferably, the portion of solvent A in step (1) accounts for 20-40% of the total mass of solvent A, for example, it can be 20%, 25%, 30%, 35% or 40%, etc.

[0046] Preferably, the reaction temperature in step (1) is 70-80℃, for example, it can be 70℃, 72℃, 74℃, 75℃, 76℃, 78℃ or 80℃, and the reaction time is 1-2 h, for example, it can be 1 h, 1.2 h, 1.5 h, 1.6 h, 1.8 h or 2 h.

[0047] Preferably, the R value of the reaction in step (1) is 0.5-0.9, for example, it can be 0.5, 0.6, 0.7, 0.8, or 0.9.

[0048] The amount of isocyanate used in step (1) of this invention is adjusted by controlling the R value of the reaction based on the different weight-average molecular weights of the polyester polyols used.

[0049] Preferably, the portion of solvent A in step (2) accounts for 10-20% of the total mass of solvent A, for example, it can be 10%, 12%, 14%, 15%, 16%, 18% or 20%, etc.

[0050] Preferably, the reaction temperature in step (2) is 70-80℃, for example, it can be 70℃, 72℃, 74℃, 75℃, 76℃, 78℃ or 80℃, etc.

[0051] Preferably, the viscosity of the system after adding the remaining solvent A in step (3) at 25°C is 250,000-300,000 cps, for example, it can be 250,000 cps, 260,000 cps, 270,000 cps, 280,000 cps, 290,000 cps or 300,000 cps.

[0052] The viscosity (at 25°C) was measured using a rotational viscometer.

[0053] Fifthly, the present invention provides a polyurethane glove, the polyurethane glove comprising a core and a polyurethane outer layer; The polyurethane outer layer is prepared from a slurry containing the polyurethane resin described in the third aspect.

[0054] Preferably, the slurry comprises, by weight, 200 parts of polyurethane resin as described in the third aspect, 0.1-2 parts of black paste, 0.1-2 parts of defoamer, and 200-400 parts of solvent B.

[0055] Among them, 0.1-2 portions can be, for example, 0.1 portions, 0.5 portions, 1 portion, 1.5 portions, or 2 portions; 200-400 portions can be, for example, 200 portions, 250 portions, 300 portions, 350 portions, or 400 portions.

[0056] Preferably, solvent B comprises N,N-dimethylformamide.

[0057] Preferably, the polyurethane gloves are prepared by the following method: The components of the slurry are mixed, the glove core is placed on a palm-shaped hand mold and immersed in the slurry, and then immersed in a coagulation tank for coagulation to obtain the polyurethane glove.

[0058] Preferably, the immersion time is 10-20 s, for example, it can be 10 s, 12 s, 14 s, 15 s, 16 s, 18 s or 20 s, etc.

[0059] Preferably, the temperature of the hand mold is 40-50℃, for example, it can be 40℃, 42℃, 44℃, 45℃, 46℃, 48℃ or 50℃, etc.

[0060] Preferably, the immersion process further includes a homogenization step.

[0061] Preferably, the homogenization time is 1-5 min, for example, it can be 1 min, 2 min, 3 min, 4 min or 5 min, etc.

[0062] Preferably, the coagulation tank contains an aqueous solution of N,N-dimethylformamide with a mass concentration of 7-12% (e.g., 7%, 8%, 9%, 10%, 11%, or 12%).

[0063] This invention employs a "palm-immersion coagulation process" and limits the coagulation tank to contain an N,N-dimethylformamide-water solution with a mass concentration of 7-12%. If the N,N-dimethylformamide-water solution concentration is too high, the polyurethane coagulation speed will be too fast, forming an extremely dense surface layer with almost no pores, resulting in a decrease in moisture permeability. If the concentration is too low, the polyurethane resin cannot be effectively coagulated, thus affecting its overall performance.

[0064] Preferably, the solidification time is 15-25 min, for example, it can be 15 min, 20 min or 25 min.

[0065] Preferably, the solidification process further includes steps of soaking in water for washing and drying.

[0066] Preferably, the soaking and washing temperature is 60-70℃, for example, 60℃, 62℃, 64℃, 65℃, 66℃, 68℃ or 70℃, and the time is 1-3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours.

[0067] Preferably, the drying temperature is 100-130℃, for example, 100℃, 105℃, 120℃, 125℃ or 130℃, and the drying time is 30-60 min, for example, 30 min, 40 min, 50 min or 60 min.

[0068] Compared with the prior art, the present invention has at least the following beneficial effects: (1) This invention designs a polyester polyol containing a rigid benzene ring, amide group and cyclohexane structure, and then combines it with 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester. The polyurethane resin is synthesized by a "two-step polymerization process" and combined with a "palm immersion coagulation process", so that the polyurethane gloves have excellent anti-slip properties, breathability and wear resistance.

[0069] (2) The polyester polyol, polyurethane resin and polyurethane gloves provided by the present invention have mild overall process conditions and simple operation, which are suitable for industrial production. The polyurethane gloves made are suitable for fields with high requirements for anti-slip and breathability, such as automobile repair, machining and construction sites, and are especially suitable for the automobile repair industry that needs to be frequently exposed to oily environments. Attached Figure Description

[0070] Figure 1 This is the infrared spectrum of the polyester polyol prepared by the present invention. Figure 2 This is the infrared spectrum test diagram of the polyurethane resin provided in Embodiment 1 of the present invention. Detailed Implementation

[0071] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0072] The specific information of the materials used in the following specific embodiments of the present invention is as follows: m-Aminobenzoic acid, model: 99-05-8, manufacturer: Jiangsu Xinsu New Materials Co., Ltd.; o-methylhydroquinone, model number: 115654, manufacturer: Shanghai Minggao Chemical Co., Ltd. 1,4-Cyclohexanediol, model number: 556-48-9, manufacturer: Hubei Xinmingtai Chemical Co., Ltd.; Adipic acid, purified adipic acid, manufacturer: Jiangsu Haili Chemical; Triphenyl phosphite, model: TPPI, manufacturer: Zhangjiagang Fengtong Chemical Co., Ltd. Tetrabutyl titanate, model: tetra-n-butyl titanate, manufacturer: Shandong Dongfang Riqi New Materials Co., Ltd. 4,4-Diphenylmethane diisocyanate, Manufacturer: Wanhua Chemical; Ethylene glycol: Manufacturer: Shandong Longhui Chemical Co., Ltd.; Hexanediol, manufacturer: Chongqing Xinshengtong Chemical Co., Ltd.; Malic acid, model: DL-malic acid, manufacturer: Henan Wanshan New Material Technology Co., Ltd.; 3-Hydroxy-2,2-dimethylpropionic acid (HPN), manufactured by BASF; Black paste, model: Dispers Black 0066 water-based black paste, manufacturer: BASF; Defoamer, model: AFE-1247, manufacturer: Dow Corning; Glove core, 13-needle nylon glove core.

[0073] For the remaining raw materials whose purchase sources are not separately listed in this invention, they are all conventional and commonly used components in the preparation of polyester polyols and polyurethane resins. Their commercially available specifications, key parameters, and usage methods are well known to those skilled in the art. Those skilled in the art can purchase raw materials that meet general industrial standards through conventional channels and, in conjunction with the process parameters disclosed in this invention, stably reproduce the technical solution of this invention. Therefore, no further information on the purchase source, manufacturer, or brand of these raw materials has been added.

[0074] Preparation Example 1 This preparation example provides a polyester polyol and its preparation method. The raw materials for preparing the polyester polyol include, by mass, 1211 parts of m-aminobenzoic acid, 1807 parts of adipic acid, 82.2 parts of o-methylhydroquinone, 1700 parts of 1,4-cyclohexanediol, 0.5 parts of triphenyl phosphite, and 0.9 parts of tetrabutyl titanate.

[0075] The preparation method includes: Triphenyl phosphite, o-methylhydroquinone, 1,4-cyclohexanediol, m-aminobenzoic acid, and adipic acid were added to a reactor, and nitrogen gas was continuously purged at a flow rate of 0.4 L / min throughout the process. The temperature of the mixture was raised to 145°C for melt polycondensation reaction for 5 h, during which water generated as a byproduct was continuously removed. The temperature was then raised to 225°C for esterification reaction for 3 h. A stepwise vacuum method was used, first maintaining the vacuum at -0.04 MPa for 4 h, then increasing the vacuum to -0.09 MPa and maintaining it for 6 h to remove water and small molecule alcohols from the reaction system. The acid value of the reaction system was checked every 30 minutes. After the acid value dropped below 28 mgKOH / g, tetrabutyl titanate was added, and the reaction continued under vacuum of -0.09 MPa and 225℃. The acid value and hydroxyl value of the reaction system were checked every 1 hour until the acid value was 0.45 mgKOH / g and the hydroxyl value was 26.2 mgKOH / g. The temperature was then lowered to 75℃, filtered, and packaged to obtain the polyester polyol (weight average molecular weight of 4210 g / mol).

[0076] The polyester polyol obtained in Example 1 of this invention was characterized by infrared spectroscopy using a Fourier transform infrared spectrometer, and the results are as follows: Figure 1 As shown in the figure. The wave number is 1727 cm⁻¹. -1 A strong absorption peak appears at 1598 cm⁻¹, which is attributed to the C=O stretching vibration of the carboxylic acid carbonyl group, proving the presence of adipic acid and aminobenzoic acid structures in the product; -1 1455 cm -1The two absorption peaks are characteristic C=C vibrations of the aromatic ring skeleton, confirming the presence of a benzene ring structure introduced by aminobenzoic acid, o-methylhydroquinone, and triphenyl phosphite in the product; 1372 cm⁻¹ -1 The absorption peak corresponds to the methyl CH vibration in o-methylhydroquinone. The peak is located between 1269 and 1018 cm⁻¹. -1 Multiple CO characteristic absorption peaks appear in the range, corresponding to various oxygen-containing functional groups in the product: among which 1269 cm⁻¹... -1 The CO stretching vibration of the phenolic hydroxyl group of o-methylhydroquinone; 1171 cm⁻¹ -1 1130 cm -1 1080 cm -1 1018 cm -1 This is a superposition of the vibrational peaks of alcohol CO, POC, and Ti-OC, and the peak at 1130 cm⁻¹ is... -1 1080 cm -1 This is a typical CO stretching vibration characteristic peak for the secondary alcohol structure of 1,4-cyclohexanediol. At 732 cm⁻¹ -1 The strong absorption peak is attributed to the out-of-plane bending vibration of the benzene ring (CH), a typical characteristic of ortho-disubstituted benzene (o-methylhydroquinone) and monosubstituted benzene (triphenyl phosphite). In summary, this confirms that the target polyester polyol has been successfully synthesized.

[0077] Preparation Example 2 This preparation example provides a polyester polyol and its preparation method. The raw materials for preparing the polyester polyol include, by mass, 1211 parts of m-aminobenzoic acid, 1807 parts of adipic acid, 52.2 parts of o-methylhydroquinone, 1750 parts of 1,4-cyclohexanediol, 0.5 parts of triphenyl phosphite, and 0.9 parts of tetrabutyl titanate.

[0078] The preparation method is the same as in Preparation Example 1, and the weight-average molecular weight of the polyester polyol is 4169 g / mol.

[0079] Preparation Example 3 This preparation example provides a polyester polyol and its preparation method. The raw materials for preparing the polyester polyol include, by mass, 1211 parts of m-aminobenzoic acid, 1807 parts of adipic acid, 115 parts of o-methylhydroquinone, 1680 parts of 1,4-cyclohexanediol, 0.5 parts of triphenyl phosphite, and 0.9 parts of tetrabutyl titanate.

[0080] The preparation method is the same as in Preparation Example 1, and the weight-average molecular weight of the polyester polyol is 4287 g / mol.

[0081] Preparation Example 4 This preparation example provides a polyester polyol and its preparation method. The raw materials for preparing the polyester polyol include, by mass, 980 parts of m-aminobenzoic acid, 1720 parts of adipic acid, 55 parts of o-methylhydroquinone, 1660 parts of 1,4-cyclohexanediol, 0.5 parts of triphenyl phosphite, and 0.9 parts of tetrabutyl titanate.

[0082] The preparation method is the same as in Preparation Example 1, and the weight-average molecular weight of the polyester polyol is 4195 g / mol.

[0083] Preparation Example 5 This preparation example provides a polyester polyol and its preparation method. The raw materials for preparing the polyester polyol include, by mass, 1450 parts of m-aminobenzoic acid, 1900 parts of adipic acid, 200 parts of o-methylhydroquinone, 1720 parts of 1,4-cyclohexanediol, 0.5 parts of triphenyl phosphite, and 0.9 parts of tetrabutyl titanate.

[0084] The preparation method is the same as in Preparation Example 1, and the weight-average molecular weight of the polyester polyol is 4061 g / mol.

[0085] Comparative Preparation Example 1 This comparative preparation example provides a polyester polyol and its preparation method. The raw materials for preparing the polyester polyol include, by mass, 2452 parts of adipic acid, 82.2 parts of o-methylhydroquinone, 1700 parts of 1,4-cyclohexanediol, 274 parts of ethylene glycol, 0.5 parts of triphenyl phosphite, and 0.9 parts of tetrabutyl titanate.

[0086] The preparation method includes: Triphenyl phosphite, o-methylhydroquinone, 1,4-cyclohexanediol, ethylene glycol, and adipic acid were added to a reactor, and nitrogen gas was continuously purged at a flow rate of 0.4 L / min throughout the process. The temperature of the mixture was raised to 145°C for melt polycondensation reaction, which lasted for 5 hours, during which water, a byproduct, was continuously removed. The temperature was then raised to 225°C for esterification reaction, which lasted for 3 hours. A stepwise vacuum method was used, first maintaining a vacuum of -0.04 MPa for 4 hours, then increasing the vacuum to -0.09 MPa and maintaining it for 6 hours to remove water and small molecule alcohols from the reaction system. The acid value of the reaction system was checked every 30 minutes. After the acid value dropped below 28 mgKOH / g, tetrabutyl titanate was added, and the reaction continued under vacuum of -0.09 MPa and 225℃. The acid value and hydroxyl value of the reaction system were checked every 1 hour until the acid value was 0.42 mgKOH / g and the hydroxyl value was 26.7 mgKOH / g. The temperature was then lowered to 75℃, filtered, and packaged to obtain the polyester polyol (weight average molecular weight of 4137 g / mol).

[0087] Comparative Preparation Example 2 This preparation example provides a polyester polyol and its preparation method. The raw materials for preparing the polyester polyol include, by mass, 1211 parts of m-aminobenzoic acid, 1807 parts of adipic acid, 82.2 parts of o-methylhydroquinone, 1729 parts of 1,6-hexanediol, 0.5 parts of triphenyl phosphite, and 0.9 parts of tetrabutyl titanate.

[0088] The preparation method includes: Triphenyl phosphite, o-methylhydroquinone, hexanediol, m-aminobenzoic acid, and adipic acid were added to a reactor, and nitrogen gas was continuously introduced throughout the process at a flow rate of 0.4 L / min. The temperature of the mixture was raised to 145℃ for melt polycondensation reaction, which lasted for 5 h, during which water generated as a byproduct was continuously removed. The temperature was then raised to 225℃ for esterification reaction, which lasted for 3 h. A stepwise vacuum method was used, first controlling the vacuum level at -0.04 MPa and maintaining it for 4 h, then increasing the vacuum level to -0.09 MPa and maintaining it for 6 h to remove water and small molecule alcohols from the reaction system. The acid value of the reaction system was checked every 30 minutes. After the acid value dropped below 28 mgKOH / g, tetrabutyl titanate was added, and the reaction continued under vacuum of -0.09 MPa and 225℃. The acid value and hydroxyl value of the reaction system were checked every 1 hour until the acid value was 0.39 mgKOH / g and the hydroxyl value was 25.9 mgKOH / g. The temperature was then lowered to 75℃, filtered, and packaged to obtain the polyester polyol (weight average molecular weight of 4267 g / mol).

[0089] Example 1 This embodiment provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include, by mass, 140 parts of polyester polyol obtained in Preparation Example 1, 36 parts of HPN, 104.8 parts of 4,4-diphenylmethane diisocyanate, 13 parts of ethylene glycol, 0.1 parts of triphenyl phosphite, 0.03 parts of phosphoric acid, 0.3 parts of methanol, 0.3 parts of malic acid, and 687 parts of N,N-dimethylformamide.

[0090] The preparation method includes: The polyester polyol obtained in Preparation Example 1, HPN, phosphoric acid, triphenyl phosphite, and N,N-dimethylformamide (29.1% of the total solvent weight) were added to a reaction vessel and stirred until homogeneous. Then, 4,4-diphenylmethane diisocyanate (42.4% of the total 4,4-diphenylmethane diisocyanate, R value 0.85) was added, and the mixture was heated to 75°C and reacted for 1.5 h. Next, N,N-dimethylformamide (14.5% of the total solvent weight) and ethylene glycol were added, and the mixture was stirred until homogeneous. Then, the remaining 4,4-diphenylmethane diisocyanate was added, and the mixture was reacted at 75°C to thicken the resin. During the thickening process, the remaining N,N-dimethylformamide was added in batches. When the viscosity of the reaction system reached 270,000 cps / 25°C, methanol was added to terminate the reaction. Then, malic acid was added, and the mixture was stirred until homogeneous. The final resin solid content of the reaction system was controlled at 30%, and stirring was continued for 1.5 h to obtain the polyurethane resin.

[0091] The polyurethane resin obtained in Example 1 of this invention was characterized by infrared spectroscopy using a Fourier transform infrared spectrometer, and the results are as follows: Figure 2 As shown in the figure, in the polyester polyol prepared in Example 1, the C=C stretching vibration of the aromatic ring in the triphenyl phosphite appears at 1598.15 cm⁻¹. -1 1511.69 cm -1 The characteristic peak of the PO-Ar bond is located at 1103.79 cm⁻¹. -1 1079.49cm -1 1018.05 cm -1 The out-of-plane bending vibration of CH in a monosubstituted benzene ring corresponds to 732.11 cm⁻¹. -1 667.02 cm -1 All characteristic peaks were detected in the spectrum. o-Methylhydroquinone: The absorption peak at C=C of the aromatic ring is 1598.15 cm⁻¹. -1 1511.69 cm -1 The phenolic hydroxyl group (OH) vibration is located at 3340.04 cm⁻¹. -1 The characteristic peak of methyl CH is at 2951.79 cm⁻¹. -1 1383.54 cm -1 Due to the influence of the benzene ring substitution structure, the out-of-plane bending vibration of the benzene ring CH appeared at 814.35 cm⁻¹. -1 This is consistent with the spectral data. 1,4-Cyclohexanediol: Aliphatic hydroxyl (OH) vibrations superimposed at 3340.04 cm⁻¹. -1 ; Saturated CH stretching vibration at 2951.79 cm -1 Predominantly; the CO bond in the alcohol corresponds to 1103.79 cm⁻¹. -1 1079.49 cm -1All of these are reflected in the spectrum. m-Aminobenzoic acid: The characteristic peak of the aromatic ring C=C is at 1598.15 cm⁻¹. -1 1511.69 cm -1 The C=O stretching vibration of the carboxyl group is located at 1728.84 cm⁻¹. -1 A slight red shift occurs after the group participates in the reaction; the amino NH vibration superimposed at 3340.04 cm⁻¹. -1 At this point, the amino bending vibration corresponds to 1651.51 cm. -1 The out-of-plane bending vibration of the meta-substituted benzene ring (CH) is 814.35 cm⁻¹. -1 732.11 cm -1 Adipic acid: The C=O vibration in the carboxyl and ester groups is located at 1728.84 cm⁻¹. -1 The characteristic peak of the CO bond is at 1269.91 cm⁻¹. -1 The saturated CH stretching vibration corresponds to 2951.79 cm. -1 The absorption peaks described above confirm that the polyester polyol prepared in Example 1 still exhibits ester bond-related characteristic peaks after esterification, indicating that the polyester polyol has been successfully introduced. Furthermore, 3-hydroxy-2,2-dimethylpropionic acid (HPN): the C=O group of the ester group appears at 1728.84 cm⁻¹. -1 The CO bond corresponds to 1269.91 cm. -1 1177.49 cm -1 The methyl CH vibration is 2951.79 cm⁻¹. -1 1383.54 cm -1 ; Hydroxyl groups (OH) superimposed at 3340.04 cm -1 4,4-Diphenylmethane diisocyanate (MDI): The NH vibration of the carbamate is located at 3340.04 cm⁻¹. -1 The carbonyl C=O value is 1728.84 cm⁻¹. -1 The C=C absorption peak of the benzene ring includes 1598.15 cm⁻¹. -1 1541.68 cm -1 1511.69 cm -1 The out-of-plane bending vibration of the para-substituted benzene ring (CH) corresponds to 814.35 cm⁻¹. -1 The 2270 cm⁻¹ region was not detected in the spectrum. -1 The characteristic peak of free isocyanate (NCO) in the vicinity proves that the NCO group has fully participated in the reaction. Ethylene glycol and methanol: the characteristic peaks of hydroxyl (OH), saturated CH, and alcohol CO are superimposed at 3340.04 cm⁻¹. -1 2951.79 cm -1 and 1103.79 cm -11079.49 cm -1 At this location, the absorption peak overlaps with that of other alcohols and phenols. Malic acid: The C=O group of the ester group formed after the reaction is located at 1728.84 cm⁻¹. -1 The hydroxyl group (OH) is superimposed at 3340.04 cm. -1 The characteristic peak of the CO bond is at 1269.91 cm⁻¹. -1 1177.49 cm -1 The saturated CH vibration corresponds to 2951.79 cm⁻¹. -1 In summary, the absorption peaks in the spectrum highly match the standard characteristic vibrational peaks of the aforementioned raw materials and reaction-generated functional groups, confirming that the structures of each component exist in the polyurethane resin system of this invention. This demonstrates that the target polyurethane resin has been successfully synthesized.

[0092] Example 2 This embodiment provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include, by weight, 150 parts of polyester polyol obtained in Preparation Example 2, 15 parts of HPN, 105.55 parts of 4,4-diphenylmethane diisocyanate, 19.4 parts of ethylene glycol, 0.1 parts of triphenyl phosphite, 0.03 parts of phosphoric acid, 0.3 parts of methanol, 0.3 parts of malic acid, and 677 parts of N,N-dimethylformamide.

[0093] The preparation method includes: The polyester polyol obtained in Preparation Example 2, HPN, phosphoric acid, triphenyl phosphite, and N,N-dimethylformamide (29.5% of the total solvent weight) were added to a reaction vessel and stirred until homogeneous. Then, 4,4-diphenylmethane diisocyanate (22% of the total 4,4-diphenylmethane diisocyanate, R value 0.85) was added, and the mixture was heated to 75°C and reacted for 1.5 h. Next, N,N-dimethylformamide (14.8% of the total solvent weight) and ethylene glycol were added, and the mixture was stirred until homogeneous. Then, the remaining 4,4-diphenylmethane diisocyanate was added, and the mixture was reacted at 75°C to thicken the resin. During the thickening process, the remaining N,N-dimethylformamide was added in batches. When the viscosity of the reaction system reached 250,000 cps / 25°C, methanol was added to terminate the reaction. Then, malic acid was added, and the mixture was stirred until homogeneous. The final resin solid content of the reaction system was controlled to be 30%, and the mixture was stirred for another 1.5 h to obtain the polyurethane resin.

[0094] Example 3 This embodiment provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include, by mass, 120 parts of polyester polyol obtained in Preparation Example 3, 50 parts of HPN, 104.46 parts of 4,4-diphenylmethane diisocyanate, 9 parts of ethylene glycol, 0.1 parts of triphenyl phosphite, 0.03 parts of phosphoric acid, 0.3 parts of methanol, 0.3 parts of malic acid, and 663 parts of N,N-dimethylformamide.

[0095] The preparation method includes: The polyester polyol obtained in Preparation Example 3, HPN, phosphoric acid, triphenyl phosphite, and N,N-dimethylformamide (30% of the total solvent weight) were added to a reaction vessel and stirred until homogeneous. Then, 4,4-diphenylmethane diisocyanate (55.5% of the total 4,4-diphenylmethane diisocyanate, R value 0.85) was added, and the mixture was heated to 75°C and reacted for 1.5 h. Next, N,N-dimethylformamide (15% of the total solvent weight) and ethylene glycol were added, and the mixture was stirred until homogeneous. Then, the remaining 4,4-diphenylmethane diisocyanate was added, and the mixture was reacted at 75°C to thicken the resin. During the thickening process, the remaining N,N-dimethylformamide was added in batches. When the viscosity of the reaction system reached 260,000 cps / 25°C, methanol was added to terminate the reaction. Then, malic acid was added, and the mixture was stirred until homogeneous. The final resin solid content of the reaction system was controlled at 30%, and stirring was continued for 1.5 h to obtain the polyurethane resin.

[0096] Example 4 This embodiment provides a polyurethane resin and its preparation method, which differs from Example 1 in that the equimolar amount of the polyester polyol obtained in Preparation Example 1 is replaced with the polyester polyol obtained in Preparation Example 4.

[0097] Example 5 This embodiment provides a polyurethane resin and its preparation method, which differs from Example 1 in that the equimolar amount of the polyester polyol obtained in Preparation Example 1 is replaced with the polyester polyol obtained in Preparation Example 5.

[0098] Example 6 This embodiment provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include, by mass, 140 parts of polyester polyol obtained in Preparation Example 1, 36 parts of HPN, 129 parts of 4,4-diphenylmethane diisocyanate, 19 parts of ethylene glycol, 0.1 parts of triphenyl phosphite, 0.03 parts of phosphoric acid, 0.3 parts of methanol, 0.3 parts of malic acid, and 758 parts of N,N-dimethylformamide.

[0099] The preparation method includes: The polyester polyol obtained in Preparation Example 1, HPN, phosphoric acid, triphenyl phosphite, and N,N-dimethylformamide (26.3% of the total solvent weight) were added to a reaction vessel and stirred until homogeneous. Then, 4,4-diphenylmethane diisocyanate (34.5% of the total 4,4-diphenylmethane diisocyanate, R value 0.85) was added, and the mixture was heated to 75°C and reacted for 1.5 h. Next, N,N-dimethylformamide (13.2% of the total solvent weight) and ethylene glycol were added, and the mixture was stirred until homogeneous. Then, the remaining 4,4-diphenylmethane diisocyanate was added, and the mixture was reacted at 75°C to thicken the resin. During the thickening process, the remaining N,N-dimethylformamide was added in batches. When the viscosity of the reaction system reached 230,000 cps / 25°C, methanol was added to terminate the reaction. Then, malic acid was added, and the mixture was stirred until homogeneous. The final resin solid content of the reaction system was controlled at 30%, and stirring was continued for 1.5 h to obtain the polyurethane resin.

[0100] Example 7 This embodiment provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include, by mass, 140 parts of polyester polyol obtained in Preparation Example 1, 36 parts of HPN, 105.77 parts of 4,4-diphenylmethane diisocyanate, 13 parts of ethylene glycol, 0.1 parts of triphenyl phosphite, 0.03 parts of phosphoric acid, 0.3 parts of methanol, 0.3 parts of malic acid, and 687 parts of N,N-dimethylformamide.

[0101] The preparation method includes: The polyester polyol obtained in Preparation Example 1, HPN, phosphoric acid, triphenyl phosphite, and N,N-dimethylformamide (29.1% of the total solvent weight) were added to a reaction vessel and stirred until homogeneous. Then, 4,4-diphenylmethane diisocyanate (49.5% of the total 4,4-diphenylmethane diisocyanate, R value 1) was added, and the mixture was heated to 75°C until the resin viscosity reached 80,000 cps / 25°C. Next, N,N-dimethylformamide (14.6% of the total solvent weight) and ethylene glycol were added, and the mixture was stirred until homogeneous. Then, the remaining 4,4-diphenylmethane diisocyanate was added, and the mixture was reacted at 75°C to thicken the resin. During the thickening process, the remaining N,N-dimethylformamide was added in batches. When the viscosity of the reaction system reached 230,000 cps / 25°C, methanol was added to terminate the reaction. Then, malic acid was added, and the mixture was stirred until homogeneous. The final resin solid content of the reaction system was controlled at 30%, and stirring was continued for 1.5 h to obtain the polyurethane resin.

[0102] Comparative Example 1 This comparative example provides a polyurethane resin and its preparation method, which differs from Example 1 in that the equimolar amount of the polyester polyol obtained in Preparation Example 1 is replaced with the polyester polyol obtained in Comparative Preparation Example 1.

[0103] Comparative Example 2 This comparative example provides a polyurethane resin and its preparation method, which differs from Example 1 in that the equimolar amount of the polyester polyol obtained in Preparation Example 1 is replaced with the polyester polyol obtained in Comparative Preparation Example 2.

[0104] Comparative Example 3 This comparative example provides a polyurethane resin and its preparation method, which differs from Example 1 in that the preparation method includes: adding the polyester polyol obtained in Preparation Example 1, HPN, ethylene glycol, phosphoric acid, triphenyl phosphite, and N,N-dimethylformamide (77.5% of the total solvent weight) into a reaction vessel and stirring until homogeneous. Then, all of the 4,4-diphenylmethane diisocyanate is added, and the temperature is raised to 75°C for reaction. When the viscosity of the reaction system reaches 230,000 cps / 25°C, methanol is added to terminate the reaction, followed by malic acid. After stirring until homogeneous, the final resin solid content of the reaction system is controlled at 30%, and stirring is continued for 1.5 h to obtain the polyurethane resin.

[0105] Comparative Example 4 This comparative example provides a polyurethane resin and its preparation method. The difference from Example 1 is that the equimolar amount of the polyester polyol obtained in Preparation Example 1 is replaced with polyester polyol PEBA-4000 (weight average molecular weight 4000, polyester polyol based on adipic acid-ethylene glycol-1,4-butanediol system).

[0106] Comparative Example 5 This comparative example provides a polyurethane resin and its preparation method, which differs from Example 1 in that the equimolar amount of HPN is replaced with the polyester polyol obtained in Preparation Example 1.

[0107] Comparative Example 6 This comparative example provides a polyurethane resin and its preparation method. The difference from Example 1 is that HPN is replaced with commercially available polyol PEBA-1000 (weight-average molecular weight 1000, a polyester polyol based on the adipic acid-ethylene glycol-1,4-butanediol system).

[0108] Application Example 1 Application Example 1 provides a polyurethane glove and its preparation method. The preparation method includes: thoroughly mixing 200 parts by weight of the polyurethane resin provided in Example 1, 1 part by weight of black paste, 1 part by weight of defoamer, and 300 parts by weight of N,N-dimethylformamide to obtain a slurry, which is then vacuum degassed and set aside for later use. A 13-needle nylon glove core is fitted onto a hand mold and preheated to 45°C. The preheated hand mold, palm down, is immersed in the prepared slurry for 20 seconds, then removed and uniformly coated for 3 minutes. The immersed hand mold is then placed in a coagulation tank containing a 10 wt% aqueous solution of N,N-dimethylformamide for 20 minutes to solidify. After solidification, the hand mold is immersed in warm water at 65°C for 2 hours, and then dried in an oven at 120°C for 40 minutes to obtain the polyurethane glove.

[0109] Application Example 2 Application Example 2 provides a polyurethane glove and its preparation method. The preparation method includes: thoroughly mixing 200 parts by weight of the polyurethane resin provided in Example 2, 0.5 parts by weight of black paste, 0.5 parts by weight of defoamer, and 250 parts by weight of N,N-dimethylformamide to obtain a slurry, which is then vacuum degassed and set aside for later use. A 13-needle nylon glove core is fitted onto a hand mold and preheated to 40°C. The preheated hand mold, palm down, is immersed in the prepared slurry for 15 seconds, then removed and uniformly coated for 3 minutes. The immersed hand mold is then placed in a coagulation tank containing a 7 wt% aqueous solution of N,N-dimethylformamide for 15 minutes to solidify. After solidification, the hand mold is immersed in warm water at 65°C for 2 hours, and then dried in an oven at 120°C for 40 minutes to obtain the polyurethane glove.

[0110] Application Example 3 Application Example 3 provides a polyurethane glove and its preparation method. The preparation method includes: thoroughly mixing 200 parts by weight of the polyurethane resin provided in Example 3, 2 parts by weight of black paste, 2 parts by weight of defoamer, and 350 parts by weight of N,N-dimethylformamide to obtain a slurry, which is then vacuum degassed and set aside for later use. A 13-needle nylon glove core is fitted onto a hand mold and preheated to 50°C. The preheated hand mold, palm down, is immersed in the prepared slurry for 15 seconds, then removed and uniformly coated for 3 minutes. The immersed hand mold is then placed in a coagulation tank containing a 12 wt% N,N-dimethylformamide aqueous solution for 25 minutes to solidify. After solidification, the hand mold is immersed in warm water at 65°C for 2 hours, and then dried in an oven at 120°C for 40 minutes to obtain the polyurethane glove.

[0111] Application Example 4-7 Application Examples 4-7 provide a polyurethane glove and its preparation method, which differ from Application Example 1 in that the polyurethane resin provided in Example 1 is replaced with the polyurethane resin provided in Examples 4-7.

[0112] Application Example 8 Application Example 8 provides a polyurethane glove and its preparation method, which differs from Application Example 1 in that the mass concentration of N,N-dimethylformamide-water solution in the coagulation tank is adjusted to 20 wt%.

[0113] Comparative Application Examples 1-6 Comparative Application Examples 1-6 provide a polyurethane glove and its preparation method, the difference from Application Example 1 is that the polyurethane resin provided in Example 1 is replaced with the polyurethane resin provided in Comparative Application Examples 1-6 in equal parts by mass.

[0114] Test methods The following performance tests were performed on the polyurethane gloves provided in corresponding use cases 1-8 and comparative application examples 1-6: (1) Anti-slip evaluation: 5W-30 machine oil was applied to the stainless steel rod, and 8 testers were asked to wear gloves and hold the steel rod. The feeling was divided into the following 3 levels: A: easy to grip, not slippery; B: requires some force to grip, not easy to slip; C: easy to slip, can not grip. (2) Water permeability (g / (m) 2 •24h): According to JIS-L-1099 A standard, the moisture permeability of the gloves is measured. The higher the moisture permeability, the less likely water vapor will accumulate when wearing gloves. (3) Abrasion resistance: The abrasion resistance of the gloves of the present invention was tested in accordance with GB 24541-2009 standard. The polyurethane gloves were cut into circles with a diameter of 38 mm. The abrasion resistance of Martindale was tested. The total mass of the loading block and the sample clamp assembly was 600 g. The sample was checked for wear every 500 revolutions. The test was stopped when the sample was worn.

[0115] The test results are shown in Table 1 below: Table 1 The test results show that: (1) As can be seen from Application Examples 1 to 8, the present invention, through formulation design of polyester polyol and polyurethane resin, produces polyurethane gloves that combine the advantages of anti-slip, breathability and wear resistance, overcoming the shortcomings of traditional products in achieving a balance of performance. The anti-slip performance can reach grade B or A, and the moisture permeability can reach 450-1850 g / (m²). 2 • 24h), wear resistance can reach 5300-8200 times.

[0116] (2) As can be seen from Application Examples 1, 7 and Comparative Application Example 3, in the preparation of polyurethane resin, the addition of too much isocyanate in step (2) results in a large R value in the system and an excessively high molecular weight of the prepolymer. This leads to uneven mixing of the soft and hard segments of the final polymer, excessively large and disordered distribution of the hard segment micro-regions, reduced grip uniformity, and blockage of the air pores by large-sized hard segments, resulting in reduced moisture permeability and decreased abrasion resistance due to stress concentration. Comparative Application Example 3 uses a one-step process to prepare polyurethane resin, resulting in almost no microphase separation between the soft and hard segments of the polyurethane resin, leading to low moisture permeability, disordered distribution of polar groups, severely deteriorated anti-slip properties, lack of physical cross-linking points, and poor abrasion resistance. This further demonstrates that the "two-step polymerization" and "under-prepolymerization" of this invention can effectively improve the anti-slip, breathable and abrasion-resistant properties of polyurethane gloves by adjusting the microstructure of the polyurethane resin.

[0117] (3) As can be seen from Application Examples 1 and 8, when the concentration of N,N-dimethylformamide in the "palm-immersion coagulation process" is too high (20%), the polyurethane resin coagulates too quickly, forming an extremely dense surface layer with almost no pores and reduced moisture permeability. However, the anti-slip performance is still Grade A, and the slight decrease in wear resistance is due to the increased brittleness of the formed dense layer.

[0118] (4) As can be seen from Application Example 1 and Comparative Application Examples 1-2, in Comparative Application Example 1, due to the lack of amide groups and benzene rings provided by m-aminobenzoic acid, the polarity of the polyurethane resin is greatly reduced, resulting in poor anti-slip and wear resistance. Moreover, the soft segments are too flexible, and although the air permeability is slightly improved, it is still constrained by the random structure, and the actual air permeability is lower than that of Application Example 1. In Comparative Application Example 2, the lack of 1,4-cyclohexane structure gives the polyurethane resin soft segments moderate rigidity. However, after using linear hexanediol, the soft segments are too flexible, the hard segments are difficult to effectively aggregate, the degree of microphase separation is reduced, resulting in decreased air permeability. At the same time, the regularity of the molecular chain is worse, and the wear resistance is low.

[0119] (5) As can be seen from Application Example 1 and Comparative Application Examples 4-6, PEBA-4000 in Comparative Application Example 4 does not contain rigid benzene rings and amide groups, and its anti-slip performance is only Grade B. Its wear resistance is lower than that of Application Example 1. However, since the soft segment of the polyurethane resin provided in Comparative Example 4 is more flexible, but the pores are uneven, the moisture permeability is improved compared to Comparative Application Example 1, but it is still lower than that of Application Example 1. In Comparative Application Example 5, HPN is used as a small molecule diol to adjust the compatibility of soft and hard segments. When it is completely replaced by the polyester polyol provided in Example 1, the polyurethane resin becomes too rigid, the proportion of hard segments is too high, the microphase separation becomes worse, the moisture permeability decreases, and the internal stress increases, resulting in poor wear resistance. In Comparative Application Example 6, PEBA-1000 is a linear polyester diol. Its linear structure induces the hard segment molecules to arrange in a regular manner, forming large hard segment microregions. These large microregions physically block the water vapor channels, leading to a sharp decrease in air permeability.

[0120] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A polyester polyol, characterized in that, The raw materials for preparing the polyester polyol include, by mass percentage, 20-30% m-aminobenzoic acid, 30-40% adipic acid, 1-4% o-methylhydroquinone, and 31-41% 1,4-cyclohexanediol.

2. The polyester polyol according to claim 1, characterized in that, The molar ratio of hydroxyl to carboxyl groups in the raw materials for preparing the polyester polyol is (1.15-1.22):1; The weight-average molecular weight of the polyester polyol is 3600-4400 g / mol; The hydroxyl value of the polyester polyol is 25-27 mgKOH / g; The acid value of the polyester polyol is <0.5 mgKOH / g; Based on a 100% mass percentage of the raw materials used in the preparation of the polyester polyol, the raw materials also include 0.005-0.1% antioxidant A and / or 0.006-0.1% catalyst. Antioxidant A includes phosphate ester antioxidants; The catalyst comprises any one or a combination of at least two of tetrabutyl titanate, tetraisopropyl titanate, stannous octoate, or dibutyltin dilaurate.

3. A method for preparing a polyester polyol as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: The polyester polyol is obtained by mixing amino-substituted m-aminobenzoic acid, adipic acid, o-methylhydroquinone and 1,4-cyclohexanediol, followed by polycondensation and esterification reactions.

4. The method for preparing polyester polyol according to claim 3, characterized in that, The mixing also includes mixing with antioxidant A; The polycondensation reaction is carried out at a temperature of 140-150℃ for 4-7 hours. The polycondensation reaction is carried out under an inert gas atmosphere; The esterification reaction is carried out at a temperature of 220-230℃; The esterification reaction includes first reacting at 220-230℃ for 2-4 h, and then reacting at 220-230℃ under vacuum conditions and in the presence of an optional catalyst until the acid value of the reaction system is <0.5 mgKOH / g and the hydroxyl value is 25-27 mgKOH / g, to obtain the polyester polyol; The vacuum level of the vacuum condition is -0.01 to -0.1 MPa.

5. A polyurethane resin, characterized in that, The raw materials for preparing the polyurethane resin include, by mass percentage, 9-18% polyester polyol as described in claim 1 or 2, 0.5-8% 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester, 5-15% isocyanate, 0.5-4% chain extender, and 60-80% solvent A.

6. The polyurethane resin according to claim 5, characterized in that, The isocyanate includes 4,4-diphenylmethane diisocyanate; The chain extender includes ethylene glycol and / or 1,4-butanediol; Solvent A includes N,N-dimethylformamide; Based on the mass percentage of the raw materials for preparing the polyurethane resin being 100%, the raw materials for preparing the polyurethane resin further include any one or a combination of at least two of the following: antioxidant B 0.001-0.03%, phosphoric acid 0.001-0.01%, chain terminator 0.01-0.05%, or anti-tackifying agent 0.01-0.05%. Antioxidant B includes phosphate ester antioxidants; The chain terminator includes methanol; The anti-tack and anti-blocking agent includes malic acid.

7. A method for preparing the polyurethane resin as described in claim 5 or 6, characterized in that, The preparation method includes the following steps: (1) The polyester polyol as described in claim 1 or 2, 3-hydroxy-2,2-dimethylpropionic acid (3-hydroxy-2,2-dimethylpropyl) ester, optional antioxidant B, optional phosphoric acid, a portion of isocyanate and a portion of solvent A are mixed and reacted. (2) Add a portion of solvent A, chain extender and another portion of isocyanate to the reaction system obtained in step (1) and carry out the reaction; (3) Add the remaining solvent A to the reaction system obtained in step (2), and then add an optional chain terminator and an optional anti-tack agent to obtain the polyurethane resin.

8. The method for preparing polyurethane resin according to claim 7, characterized in that, In step (1), a portion of solvent A accounts for 20-40% of the total mass of solvent A; The reaction temperature in step (1) is 70-80℃, and the reaction time is 1-2 h; The R value of the reaction in step (1) is 0.5-0.9; In step (2), a portion of solvent A accounts for 10-20% of the total mass of solvent A; The reaction temperature described in step (2) is 70-80℃; The viscosity of the system after adding the remaining solvent A in step (2) is 250,000-300,000 cps at 25°C.

9. A polyurethane glove, characterized in that, The polyurethane glove includes a core and a polyurethane outer layer; The polyurethane outer layer is prepared from a slurry containing the polyurethane resin as described in claim 5 or 6.

10. The polyurethane glove according to claim 9, characterized in that, The slurry comprises, by weight, 200 parts of the polyurethane resin as described in claim 5 or 6, 0.1-2 parts of black paste, 0.1-2 parts of defoamer, and 200-400 parts of solvent B; Solvent B includes N,N-dimethylformamide; The polyurethane gloves are prepared by the following method: The components of the slurry are mixed, the glove core is placed on a palm-shaped hand mold and immersed in the slurry, and then immersed in a coagulation tank for coagulation to obtain the polyurethane glove. The immersion time is 10-20 seconds; The temperature of the hand mold is 40-50℃; The process after immersion also includes a homogenization step; The homogenization time is 1-5 min; The coagulation tank contains an aqueous solution of N,N-dimethylformamide with a mass concentration of 7-12%. The solidification time is 15-25 min; The solidification process also includes steps of soaking in water for washing and drying. The soaking and washing process is carried out at a temperature of 60-70℃ for 1-3 hours. The drying temperature is 100-130℃ and the time is 30-60 min.

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