Temperature self-regulating high-solid blocked polyurethane resin and preparation method thereof
By introducing phase change polyether polyol and temperature-sensitive chain extender into the closed polyurethane resin, the temperature self-regulation of the high solids closed polyurethane resin was achieved, solving the problem of local overheating, improving the construction performance and product quality, and meeting environmental protection requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIAXING HEXIN CHEM IND
- Filing Date
- 2026-04-08
- Publication Date
- 2026-06-09
AI Technical Summary
High-solids-content closed-cell polyurethane resins are prone to local overheating during use and curing due to concentrated exothermic reactions, high system viscosity, and poor thermal conductivity. This can lead to shortened gel time, narrowed application window, and even resin charring and degradation. Existing solutions have limited effectiveness or violate the original intention of environmental protection.
Through molecular structure design, a temperature-regulating high-solids closed polyurethane resin composed of a closed polyurethane prepolymer and an amine curing agent is used. By utilizing the phase change and conformational change of phase change polyether polyol and temperature-sensitive chain extender, the material properties can be reversibly and intelligently controlled with temperature, avoiding local overheating.
It achieves intelligent temperature response of polyurethane resin, improves construction performance, extends service life, meets the needs of high-end automotive leather, has self-healing potential, complies with environmental regulations, and reduces solvent pollution.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of closed polyurethane, and in particular to a temperature-self-regulating high-solids closed polyurethane resin and its preparation method. Background Technology
[0002] Polyurethane resins are widely used in coatings, adhesives, sealants, synthetic leather, and elastomers due to their excellent mechanical properties, abrasion resistance, chemical stability, cold resistance, and impact resistance. Blocked polyurethane refers to polyurethane prepolymers where the isocyanate groups are temporarily protected by a blocking agent, allowing for stable storage at room temperature. When heated to a certain temperature (the deblocking temperature), the blocking agent dissociates, releasing the active isocyanate groups, which then undergo a cross-linking and curing reaction with compounds containing active hydrogen (such as polyols, water, and amines). High-solids blocked polyurethane systems aim to reduce volatile organic compound emissions, complying with environmental regulations.
[0003] However, high-solids-content closed-cell polyurethane resins are prone to internal heat accumulation and localized overheating during use and curing due to concentrated exothermic reactions, high viscosity, and poor thermal conductivity. Localized overheating can cause a series of problems, such as: 1) accelerated reaction leading to shorter gel time and a narrower application window; 2) in severe cases, resin charring and degradation, resulting in decreased product performance. Currently, solutions to localized overheating typically involve external cooling, controlling the addition rate, or using high-boiling-point solvents. However, these methods have limited effectiveness, are costly, or contradict the environmentally friendly principles of high-solids-content resins. Therefore, developing a high-solids-content polyurethane resin capable of autonomously regulating temperature is crucial for solving the overheating problem during curing and improving product quality. Summary of the Invention
[0004] To address the problem of overheating during curing of existing high-solids-content closed-cell polyurethane resins, this invention provides a temperature-self-regulating high-solids-content closed-cell polyurethane resin and its preparation method. Through molecular structure design, the material properties are reversibly and intelligently regulated with temperature, thus solving the problem of overheating during curing of high-solids-content closed-cell polyurethane.
[0005] The present invention provides a temperature-self-regulating high-solids sealed polyurethane resin, which is achieved through the following technical solution: A temperature-regulating high-solids blocked polyurethane resin comprises a blocked polyurethane prepolymer and an amine curing agent in a mass ratio of 100:(8-14); the blocked polyurethane prepolymer comprises diisocyanate, phase change polyether polyol, polycarbonate diol thermosensitive chain extender, blocking agent, catalyst, organic solvent, and functional additives; the phase change polyether polyol has a molecular chain segment containing crystallizable soft segments, and a phase change temperature of -10℃ to 60℃; the thermosensitive chain extender is a diamine containing dynamic reversible covalent bonds and / or a diol containing dynamic reversible covalent bonds.
[0006] This invention overcomes the problem of localized overheating during the use and curing of polyurethane resin. The high-grade automotive leather obtained by using the temperature-regulating high-solids sealed polyurethane of this invention is intelligent, has good thermal stability, and has an extended service life, meeting the market demand for high-grade automotive leather.
[0007] Specifically, this invention employs a temperature-regulating high-solids closed-type polyurethane resin composition composed of a closed-type polyurethane resin and an amine curing agent. The isocyanate reacts with the hydroxyl component to generate a terminal isocyanate prepolymer with a smaller molecular weight and lower viscosity. A thermally dissociable sealing agent reacts with the terminal isocyanate to form a closed-type polyurethane that can be stably stored at room temperature. When used, an amine curing agent is added, resulting in a long shelf life at room temperature. It exhibits processability similar to traditional single-component resins, eliminating solvent contamination in traditional synthetic leather production. Simultaneously, the sealing agent de-seales at high temperatures, allowing the amine curing agent to rapidly react and cure, resulting in high efficiency and energy saving. This also achieves a dense, pore-free coating, improving leather performance.
[0008] Preferably, the phase change polyether polyol is at least one of polycaprolactone polyol, polytetrahydrofuran polyol, ethylene oxide and propylene oxide block copolymer polyol with a molecular weight of 2000-6000.
[0009] Selectively, the phase change polyether polyol is a polycaprolactone polyol with a molecular weight of 2000.
[0010] By adopting the above technical solution, the polycaprolactone polyol segments undergo a reversible crystallization-melting transformation at a specific temperature (phase transition temperature Tm). When the temperature is below Tm, the soft segments crystallize, serving as physical crosslinking points and significantly improving the resin's modulus and strength. When the temperature is above Tm, the soft segments melt, enhancing chain mobility, softening the material, and decreasing the modulus. This phase transition behavior is the core driving force for the temperature-dependent self-regulation of material properties. Furthermore, the polycaprolactone polyol works well when used in conjunction with the temperature-sensitive chain extender provided in this invention, facilitating application.
[0011] Preferably, the temperature-sensitive chain extender is a furanylmaleamide compound or an acylhydrazone compound. These temperature-sensitive chain extenders exhibit good hydrophilicity / compatibility at low temperatures and are well miscible with the polyurethane matrix. As the temperature increases, the molecular chains collapse and become hydrophobic, causing a change in their distribution within the micro-regions of the polyurethane hard segments. This change dynamically affects the ordered arrangement of the hard segments during the curing reaction, making the curing reaction more temperature-sensitive. Specifically, slow cross-linking can be initiated slightly below the traditional unblocking temperature, achieving "pre-curing." As the temperature further increases, the reaction accelerates. This characteristic endows high-solids blocked polyurethane resins with a wider processing window and a milder curing curve.
[0012] Preferably, the diisocyanate is at least one selected from 4,4'-diphenylmethane diisocyanate (MDI-100), a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate (MDI-50), toluene diisocyanate (TDI), isoflurone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).
[0013] Preferably, the catalyst is at least one of an amine catalyst and an organometallic catalyst.
[0014] Preferably, the amine catalyst is triethanolamine and / or triethylenediamine.
[0015] Preferably, the organometallic catalyst is at least one selected from organotin, organobismuth, organopotassium, and organozinc.
[0016] Preferably, the polycarbonate diol is a caprolactone-type polycarbonate with a molecular weight of 2000 and an initiator of ε-caprolactone PCL.
[0017] By adopting the above technical solution, the polyurethane obtained can be guaranteed to have excellent weather resistance, hydrolysis resistance and wear resistance. At the same time, the caprolactone-type polycarbonate diol has a low viscosity among polycarbonate diols, which gives the present application excellent processing performance, and it works well when used in combination with the polyether polyol provided in the present application.
[0018] Preferably, the blocking agent is at least one of methyl ethyl ketone oxime and 3,5-dimethylpyrazole.
[0019] More preferably, the blocking agent is a compound of methyl ethyl ketone oxime and 3,5-dimethylpyrazole, wherein the molar ratio of methyl ethyl ketone oxime to 3,5-dimethylpyrazole is (7.8-8.2):(1.8-2.2).
[0020] The advantages of 3,5-dimethylpyrazole are: low unsealing temperature, high unsealing efficiency, and improved curing speed. The disadvantages are that a too-fast unsealing speed is detrimental to degassing and leveling during the pre-baking stage, and the solid end-capping agent leads to higher resin viscosity, making it difficult to process. Liquid methyl ethyl ketone oxime end-capping agents have lower resin viscosity than solid end-capping agents, a slightly higher unsealing temperature, and a moderate curing speed, which is beneficial for degassing and leveling during the pre-baking stage. However, the curing speed is generally moderate. Therefore, by optimizing the mass ratio of methyl ethyl ketone oxime and 3,5-dimethylpyrazole to obtain a compound end-capping agent, highly efficient sealing and a lower unsealing temperature can be achieved, while simultaneously obtaining a low-viscosity, solvent-free, closed-type polyurethane, giving this invention excellent processing performance.
[0021] Preferably, the amine curing agent includes any one of 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 4,4-diaminodicyclohexylmethane, and isoflurane diamine.
[0022] More preferably, when the amine curing agent is a mixture of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane and triethylenetetramine, then triethylenetetramine accounts for 4-8 wt% of the total mass of the amine curing agent.
[0023] By optimizing the composition and ratio of amine curing agents, multifunctional amine curing agents can be used to increase the degree of crosslinking. Appropriate addition can improve the low-temperature curing rate, peel strength, and peel strength retention rate. The resulting product has high strength after curing and can better maintain peel strength under high temperature and high humidity conditions.
[0024] Preferably, the functional additives include defoamers, leveling agents, and antioxidants. The defoamer is an organosilicon defoamer, including at least one of BYK-060N, BYK-066N, and BYK-A530. The leveling agent is any one of BYK-UV3510, BYK-UV3500, TEGOFlow300, TEGORad2200N, and TEGORad2100. The antioxidant is at least one of antioxidant 245, antioxidant 1010, antioxidant 1035, antioxidant 1076, antioxidant 1098, and antioxidant 3114.
[0025] Preferably, the temperature-regulating high-solids blocked polyurethane resin is prepared from the following raw materials in parts by weight: 40-70 parts by weight of phase change polyether polyol, 10-20 parts by weight of polycarbonate diol, 5-20 parts by weight of diisocyanate, 2-10 parts by weight of temperature-sensitive chain extender, 5-10 parts by weight of blocking agent, 0.01-0.5 parts by weight of catalyst, 0-20 parts by weight of organic solvent, and 0.2-2 parts by weight of functional additives.
[0026] The working principle and beneficial effects of this invention are as follows: During the curing process, when the temperature rises to the de-blocking temperature of the sealant (usually 120-160℃), the sealant dissociates, releasing active -NCO groups. At this time, the ambient temperature also exceeds the critical temperature of the temperature-sensitive chain extender, causing conformational changes in the chain segments, reducing their activity, and temporarily "withdrawing" from the crosslinking reaction. This results in a relatively slow initial crosslinking reaction rate and a slower increase in system viscosity, which is beneficial for coating leveling, substrate wetting, and bubble escape. As the curing process continues, heat is transferred to the interior of the coating. When the local temperature exceeds a higher threshold due to exothermic reaction or external heating, or as the small molecule crosslinking agent is consumed, the chain segments of the temperature-sensitive chain extender partially regain their activity and re-participate in the later crosslinking reaction, ensuring the final formation of a fully cured three-dimensional network structure, endowing the resulting synthetic leather with excellent mechanical properties, weather resistance, and high peel strength.
[0027] The present invention provides a method for preparing a temperature-self-regulating high-solids blocked polyurethane resin, which is achieved through the following technical solution: A method for preparing a temperature-self-regulating high-solids blocked polyurethane resin includes the following steps: S1. Synthesis of prepolymer: Under inert gas protection, accurately measured diisocyanate, phase change polyether polyol, and polycarbonate diol are added to a reactor and reacted at 70-90℃ for 2-4 hours until the -NCO content in the system reaches the theoretical value, thus obtaining a polyurethane prepolymer with terminal -NCO. S2. Chain extension and blocking: Cool the reaction system to 50-70℃, add a accurately measured temperature-sensitive chain extender, react for 0.5-1.5 hours until the NCO mass fraction reaches 2.5±0.5%, then add an accurately measured blocking agent and catalyst, and carry out the blocking reaction at 60-80℃ until the NCO mass fraction is 0. S3. Blending and Discharging: Add accurately measured functional additives and organic solvents, mix evenly, cool to below 40°C, and discharge to obtain a closed polyurethane prepolymer; S4. Mix the closed polyurethane prepolymer from S3 with the amine curing agent at a mass ratio of 100:(8-14) until homogeneous. Discharge the mixture to obtain the temperature-regulating high-solids closed polyurethane resin product.
[0028] The preparation method provided by this invention is relatively simple and easy to mass-produce in industrial applications. Moreover, compared with traditional solvent-based resin processes, the preparation method provided by this application does not have any solvent pollution problems and is clean and environmentally friendly.
[0029] In summary, the present invention has the following advantages: 1. Intrinsic Intelligence: The temperature response characteristics originate from the intrinsic structural design of the resin molecules, rather than from external fillers. Therefore, high-solids blocked polyurethane resins are endowed with the advantages of sensitive, uniform and long-lasting response.
[0030] 2. Adjustable function: By changing the type (phase change temperature) of the phase change polyether polyol and the type and amount of the temperature-sensitive chain extender, the response temperature range and response amplitude of the material can be precisely controlled to meet the needs of different application scenarios.
[0031] 3. High solids and environmentally friendly: It has a high content of closed-cell polyurethane resin and a low content of solvents, which meets the requirements of environmental protection regulations.
[0032] 4. One agent, multiple uses: The single-component system is easy to use and has both conventional protection and intelligent regulation functions.
[0033] 5. Self-healing potential: It has the ability to self-heal at specific temperatures, which can extend the service life of the product.
[0034] 6. Excellent workability: The viscosity rises slowly in the early stage of curing, and the leveling properties are excellent, which can reduce defects such as orange peel and pinholes, improve product quality, and enhance the product's market competitiveness.
[0035] 7. The preparation method provided by this invention is relatively simple and easy to mass-produce in industrial applications. Compared with traditional solvent-based resin processes, the preparation method provided by this application has less solvent content, less pollution, and is cleaner and more environmentally friendly. Detailed Implementation
[0036] To further understand the inventiveness and technical advancements of this invention, the preferred embodiments of this invention will be discussed in detail below with reference to examples and comparative examples.
[0037] Example: A temperature-self-regulating high-solids blocked polyurethane resin, comprising a blocked polyurethane prepolymer and an amine curing agent at a mass ratio of 100:(8-14). The amine curing agent comprises any one of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, and isoflurane diamine. Preferably, the amine curing agent is a mixture of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane and triethylenetetramine, wherein the triethylenetetramine accounts for 4-8 wt% of the total mass of the amine curing agent.
[0038] Blocked polyurethane prepolymers are made from diisocyanate, phase change polyether polyol, polycarbonate diol thermosensitive chain extender, blocking agent, catalyst, organic solvent, and functional additives.
[0039] Preferably, the temperature-self-regulating high-solids blocked polyurethane resin is prepared from the following raw materials in parts by weight: 40-70 parts by weight of phase change polyether polyol, 10-20 parts by weight of polycarbonate diol, 5-20 parts by weight of diisocyanate, 2-10 parts by weight of temperature-sensitive chain extender, 5-10 parts by weight of blocking agent, 0.01-0.5 parts by weight of catalyst, 0-20 parts by weight of organic solvent, and 0.2-2 parts by weight of functional additives.
[0040] The phase change polyether polyol contains crystallizable soft segments in its molecular chain, and its phase change temperature ranges from -10°C to 60°C. Specifically, the phase change polyether polyol is at least one of polycaprolactone polyol, polytetrahydrofuran polyol, and block copolymer polyols of ethylene oxide and propylene oxide with a molecular weight of 2000-6000. Preferably, the phase change polyether polyol is a polycaprolactone polyol with a molecular weight of 2000.
[0041] The thermosensitive chain extender is a diamine containing a dynamic reversible covalent bond and / or a diol containing a dynamic reversible covalent bond. Preferably, the thermosensitive chain extender is a furanylmaleamide compound or an acylhydrazone compound. Specifically, it is hydroxyl-terminated poly(N-isopropylacrylamide) (HPNIPAM), poly(N-isopropylacrylamide) diol, or furanylmaleamide diol (a dihydroxy compound containing a DA bond) as described in the examples.
[0042] The diisocyanate is at least one selected from 4,4'-diphenylmethane diisocyanate (MDI-100), a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate (MDI-50), toluene diisocyanate (TDI), isoflurone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).
[0043] The catalyst is at least one of an amine catalyst and an organometallic catalyst. The amine catalyst is triethanolamine and / or triethylenediamine. The organometallic catalyst is at least one of organotin, organobismuth, organopotassium, and organozinc. Preferably, the organometallic catalyst is organobismuth, such as bismuth octanoate.
[0044] The polycarbonate diol is a caprolactone-type polycarbonate with a molecular weight of 2000 and ε-caprolactone PCL as the initiator.
[0045] The blocking agent is at least one of methyl ethyl ketone oxime and 3,5-dimethylpyrazole. Preferably, the blocking agent is a compound of methyl ethyl ketone oxime and 3,5-dimethylpyrazole, wherein the molar ratio of methyl ethyl ketone oxime to 3,5-dimethylpyrazole is (7.8-8.2):(1.8-2.2).
[0046] Functional additives include defoamers, leveling agents, and antioxidants.
[0047] The defoamer is an organosilicon defoamer, including at least one of BYK-060N, BYK-066N, and BYK-A530.
[0048] The leveling agent is any one of BYK-UV3510, BYK-UV3500, TEGOFlow300, TEGORad2200N, or TEGORad2100.
[0049] The antioxidant is at least one of antioxidant 245, antioxidant 1010, antioxidant 1035, antioxidant 1076, antioxidant 1098, and antioxidant 3114.
[0050] A method for preparing a temperature-self-regulating high-solids blocked polyurethane resin includes the following steps: S1. Synthesis of prepolymer: Under inert gas protection, accurately measured diisocyanate, phase change polyether polyol, and polycarbonate diol are added to a reactor and reacted at 70-90℃ for 2-4 hours until the -NCO content in the system reaches the theoretical value, thus obtaining a polyurethane prepolymer with terminal -NCO. S2. Chain extension and blocking: Cool the reaction system to 50-70℃, add a accurately measured temperature-sensitive chain extender, react for 0.5-1.5 hours until the NCO mass fraction reaches 2.5±0.5%, then add an accurately measured blocking agent and catalyst, and carry out the blocking reaction at 60-80℃ until the NCO mass fraction is 0. S3. Blending and Discharging: Add accurately measured functional additives and organic solvents, mix evenly, cool to below 40°C, and discharge to obtain a closed polyurethane prepolymer; S4. Mix the closed polyurethane prepolymer from S3 with the amine curing agent at a mass ratio of 100:(8-14) until homogeneous. Discharge the mixture to obtain the temperature-regulating high-solids closed polyurethane resin product.
[0051] Temperature-self-regulating high-solids closed-type polyurethane resin is used to prepare high-grade automotive leather. The specific preparation method is as follows: After mixing the temperature-self-regulating high-solids closed-type polyurethane resin composition, it is applied to the polyurethane surface layer, preheated at 90-120℃ for 10 minutes to level and degas, placed in an oven at 130-150℃, and cured for 1-5 minutes. After semi-drying, it is bonded to the base fabric and dried to obtain temperature-self-regulating synthetic leather.
[0052] Example 1: A temperature-self-regulating high-solids blocked polyurethane resin is prepared from the following raw materials in parts by weight: 100 parts blocked polyurethane prepolymer, 10 parts amine curing agent. The specific formula is shown in Table 1. Table 1: Ingredient list of temperature-self-regulating high-solids blocked polyurethane resin in Example 1
[0053] A method for preparing a temperature-self-regulating high-solids blocked polyurethane resin includes the following steps: S1, add 25.78g of 4,4'-diphenylmethane diisocyanate to a three-necked flask, heat to 30℃, add 0.3g of antioxidant 1010, stir for 10min, and set aside. S2, add 276g of polycaprolactone with an average molecular weight of 2000, 108g of polycarbonate diol and 150g of dimethylformamide to a three-necked flask in sequence, stir well and then heat to 70℃ and react for 1h. S3, add 10g of temperature-sensitive chain extender (hydroxyl-terminated poly(N-isopropylacrylamide) HPNIPAM), maintain the reaction at 70℃ for 1.5h, take a sample to detect the -NCO content in the prepolymer in the three-necked flask, until the -NCO mass fraction content reaches 2.5%, and obtain the terminal isocyanate prepolymer for later use. S4, 21.52 g of methyl ethyl ketone oxime, 5.38 g of 3,5-dimethylpyrazole, and 0.12 g of bismuth caprylate were added to a three-necked flask for end-capping reaction. The reaction was carried out at 80 °C for 1.5 h. The content of -NCO in the material in the three-necked flask was measured until the mass content of NCO in the system was 0%. S5, add 4.8g of leveling agent BYK-306, 0.6g of defoamer BYK-060N, and 0.3g of antioxidant 1010 to a three-necked flask, stir for 30 minutes, and then cool to room temperature to obtain a closed polyurethane prepolymer. S6, the blocked polyurethane prepolymer prepared in S5 is mixed with 3,3-dimethyl-4,4-diaminodicyclohexylmethane and triethylenetetramine at a mass ratio of 100:7.6:0.4 to obtain a temperature-regulating high-solids blocked polyurethane resin.
[0054] Temperature-regulating high-solids closed-cell polyurethane resin is used to prepare high-grade automotive leather. The specific preparation method is as follows: After mixing the temperature-regulating high-solids closed-cell polyurethane resin composition, it is scraped onto HX-6120 (hydrolysis-resistant polyurethane surface resin produced by Zhejiang Hexin Technology Co., Ltd.), preheated at 120℃ for 10 minutes, and reacted in an oven at 145℃ for 5 minutes to fully cure. Then, the base material HX-GD45 (high-solids base material produced by Zhejiang Hexin Technology Co., Ltd.) is applied, the base fabric is attached, and after drying, it is peeled off to obtain temperature-regulating synthetic leather.
[0055] The difference between Example 2 and Example 1 is that the amine curing agent in the temperature-regulating high-solids blocked polyurethane resin formulation is only 3,3-dimethyl-4,4-diaminodicyclohexylmethane. In the preparation process of the temperature-regulating high-solids blocked polyurethane resin, in step S6, the blocked polyurethane prepolymer prepared in step S5 is mixed uniformly with 3,3-dimethyl-4,4-diaminodicyclohexylmethane at a mass ratio of 100:8 to obtain the temperature-regulating high-solids blocked polyurethane resin. The remaining steps are the same.
[0056] The difference between Example 3 and Example 1 is that: a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 10 parts of amine curing agent.
[0057] The difference between Example 4 and Example 1 is that: a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 12 parts of amine curing agent.
[0058] The difference between Example 5 and Example 1 is that: a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 14 parts of amine curing agent.
[0059] The difference between Example 6 and Example 1 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) HPNIPAM in the temperature-self-regulating high-solids blocked polyurethane resin formulation is replaced with 10g of poly(N-isopropylacrylamide) diol (molecular weight 4000, hydroxyl value 28.05 mg KOH / g, Xi'an Qiyue Biotechnology Co., Ltd.), while the other components remain unchanged.
[0060] The difference between Example 7 and Example 1 is that 276g of polycaprolactone with a molecular weight of 2000 from Kelia Polyol (Nanjing) Co., Ltd. was replaced with 276g of block copolymer polyol of ethylene oxide and propylene oxide with a molecular weight of 2000 from Zhejiang Lvkoan Chemical Co., Ltd., while the other components remained unchanged.
[0061] The difference between Example 8 and Example 1 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) HPNIPAM in the temperature-self-regulating high-solids blocked polyurethane resin formulation is replaced with 10g of furanylmaleamide diol (N,N'-bis(2-hydroxyethyl)furan-2,5-dicarboxamide, molecular weight 296.27, hydroxyl value 378.7mg KOH / g) from Ningbo Huafu New Material Technology Co., Ltd.
[0062] The difference between Example 9 and Example 1 is that the formulation of the closed polyurethane prepolymer is as follows: 35.98g of TDI (Wanhua Chemical Group Co., Ltd.), 266g of polycaprolactone with a molecular weight of 2000, 108g of polycarbonate diol CD220PL, 10g of thermosensitive chain extender - hydroxyl-terminated poly(N-isopropylacrylamide) HPNIPAM, 21.52g of methyl ethyl ketone oxime, 5.38g of 3,5-dimethylpyrazole, 150g of dimethylformamide, 0.12g of bismuth caprylate, 4.8g of leveling agent BYK-306, 0.6g of defoamer BYK-060N, and 0.6g of antioxidant 1010.
[0063] The difference between Example 10 and Example 9 is that: a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 10 parts of amine curing agent.
[0064] The difference between Example 11 and Example 9 is that: a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 12 parts of amine curing agent.
[0065] The difference between Example 12 and Example 9 is that: a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 14 parts of amine curing agent.
[0066] The difference between Comparative Example 1 and Example 1 is that the 276g of polycaprolactone with a molecular weight of 2000 from Kelia Polyol (Nanjing) Co., Ltd. in the high solids blocked polyurethane resin formulation was replaced with 276g of polyoxypropylene glycol with a molecular weight of 2000 from Shanghai Gaoqiao Petrochemical Co., Ltd., while the other components remained unchanged.
[0067] The difference between Comparative Example 2 and Example 1 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) (HPNIPAM) in the high-solids blocked polyurethane resin formulation was replaced with 7.97g of 1,4-butanediol from Donghua Tianye New Materials Co., Ltd.
[0068] The difference between Comparative Example 3 and Example 1 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) (HPNIPAM) in the high-solids blocked polyurethane resin formulation was replaced with 5.49g of ethylene glycol from Donghua Tianye New Materials Co., Ltd.
[0069] The difference between Comparative Example 4 and Example 1 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) (HPNIPAM) in the high-solids blocked polyurethane resin formulation was replaced with 9.21g of neopentyl glycol from Donghua Tianye New Materials Co., Ltd.
[0070] The difference between Comparative Example 5 and Example 1 is that a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 6 parts of amine curing agent.
[0071] The difference between Comparative Example 6 and Example 1 is that a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 16 parts of amine curing agent.
[0072] The difference between Comparative Example 7 and Example 9 is that the 266g of polycaprolactone with a molecular weight of 2000 from Kelia Polyol (Nanjing) Co., Ltd. in the high solids blocked polyurethane resin formulation was replaced with 266g of polyoxypropylene glycol with a molecular weight of 2000 from Shanghai Gaoqiao Petrochemical Co., Ltd., while the other components remained unchanged.
[0073] The difference between Comparative Example 8 and Example 9 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) (HPNIPAM) in the high-solids blocked polyurethane resin formulation was replaced with 7.97g of 1,4-butanediol from Donghua Tianye New Materials Co., Ltd.
[0074] The difference between Comparative Example 9 and Example 9 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) (HPNIPAM) in the high-solids blocked polyurethane resin formulation was replaced with 5.49g of ethylene glycol from Donghua Tianye New Materials Co., Ltd.
[0075] The difference between Comparative Example 10 and Example 9 is that 10g of hydroxyl-terminated poly(N-isopropylacrylamide) (HPNIPAM) in the high-solids blocked polyurethane resin formulation was replaced with 9.21g of neopentyl glycol from Donghua Tianye New Materials Co., Ltd.
[0076] The difference between Comparative Example 11 and Example 9 is that a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 6 parts of amine curing agent.
[0077] The difference between Comparative Example 12 and Example 9 is that a temperature-self-regulating high-solids blocked polyurethane resin is made from the following raw materials in parts by weight: 100 parts of blocked polyurethane resin and 16 parts of amine curing agent.
[0078] Performance Testing: 1. Solid Content: The solid content of the high-solids blocked polyurethane resin was determined by measuring the percentage of residual solids after solvent evaporation by heating. 2. Viscosity: The viscosity of the high-solids blocked polyurethane resin in Examples 1-12 and Comparative Examples 1-12 was determined using a rotational viscometer (DV2T). 3. Peel Strength: The peel strength of automotive leather prepared with temperature-regulating high-solids blocked polyurethane resin was tested according to QB / T 2888-2007 standard. 4. Hydrolysis Resistance Test: After 10 weeks of jungle testing in a constant temperature and humidity chamber at 70℃ / 95%RH, the peel strength of automotive leather prepared with temperature-regulating high-solids blocked polyurethane resin was tested according to QB / T 2888-2007 standard. 5. Weather Resistance-Light Resistance-Jungle Test: After the automotive leather prepared with temperature-regulating high-solids blocked polyurethane resin was placed in an environment of 80℃ and 75% humidity for 400 hours, it was removed and placed at -15℃ for 50,000 bending cycles. The appearance of cracks at the bending points was observed.
[0079] Table 2: Performance test parameters of high-solids closed polyurethane resins in Examples 1-8 and Comparative Examples 1-6
[0080] Table 3: Performance test parameters of high-solids closed polyurethane resins in Examples 9-12 and Comparative Examples 7-12
[0081] As can be seen from Examples 1-12 and Comparative Examples 1-12 and Tables 2-3, the present invention achieves "intelligent" control of the polyurethane curing process by using phase change polyether polyol and temperature-sensitive chain extender: suppressing excessively fast reaction in the early stage of curing and improving processing performance; ensuring complete reaction in the later stage of curing, obtaining high-performance automotive leather products with high solid content of closed polyurethane resin, low solvent content, less pollution, and cleaner and more environmentally friendly.
[0082] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.
Claims
1. A temperature-self-regulating high-solids sealed polyurethane resin, characterized in that: The temperature-regulating high-solids blocked polyurethane resin comprises a blocked polyurethane prepolymer and an amine curing agent in a mass ratio of 100:(8-14); the blocked polyurethane prepolymer comprises diisocyanate, phase change polyether polyol, polycarbonate diol thermosensitive chain extender, blocking agent, catalyst, organic solvent, and functional additives; the phase change polyether polyol contains crystallizable soft segments in its molecular chain, and its phase change temperature is -10℃ to 60℃; the thermosensitive chain extender is a diamine containing dynamic reversible covalent bonds and / or a diol containing dynamic reversible covalent bonds.
2. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 1, characterized in that: The phase change polyether polyol is at least one of polycaprolactone polyol, polytetrahydrofuran polyol, ethylene oxide and propylene oxide block copolymer polyol with a molecular weight of 2000-6000.
3. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 1, characterized in that: The diisocyanate is at least one selected from 4,4'-diphenylmethane diisocyanate (MDI-100), a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate (MDI-50), toluene diisocyanate (TDI), isoflurone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).
4. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 1, characterized in that: The polycarbonate diol is a caprolactone-type polycarbonate with a molecular weight of 2000 and ε-caprolactone PCL as the initiator.
5. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 1, characterized in that: The blocking agent is at least one of methyl ethyl ketone oxime and 3,5-dimethylpyrazole.
6. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 5, characterized in that: The blocking agent is a compound of methyl ethyl ketone oxime and 3,5-dimethylpyrazole, and the molar ratio of methyl ethyl ketone oxime to 3,5-dimethylpyrazole is (7.8-8.2):(1.8-2.2).
7. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 1, characterized in that: The amine curing agent includes any one of 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 4,4-diaminodicyclohexylmethane, and isoflurane diamine.
8. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 1, characterized in that: The catalyst is at least one of amine catalysts and organometallic catalysts; the amine catalyst is triethanolamine and / or triethylenediamine; the organometallic catalyst is at least one of organotin, organobismuth, organopotassium, and organozinc.
9. The temperature-self-regulating high-solids sealed polyurethane resin according to claim 1, characterized in that: The functional additives include defoamers, leveling agents, and antioxidants. The defoamer is an organosilicon defoamer, including at least one of BYK-060N, BYK-066N, and BYK-A530. The leveling agent is any one of BYK-UV3510, BYK-UV3500, TEGOFlow300, TEGORad2200N, and TEGORad2100. The antioxidant is at least one of antioxidant 245, antioxidant 1010, antioxidant 1035, antioxidant 1076, antioxidant 1098, and antioxidant 3114.
10. A method for preparing a temperature-self-regulating high-solids blocked polyurethane resin according to any one of claims 1-9, characterized in that: Includes the following steps: S1. Synthesis of prepolymer: Under inert gas protection, accurately measured diisocyanate, phase change polyether polyol, and polycarbonate diol are added to a reactor and reacted at 70-90℃ for 2-4 hours until the -NCO content in the system reaches the theoretical value, thus obtaining a polyurethane prepolymer with terminal -NCO. S2. Chain extension and blocking: Cool the reaction system to 50-70℃, add a accurately measured temperature-sensitive chain extender, react for 0.5-1.5 hours until the NCO mass fraction reaches 2.5±0.5%, then add an accurately measured blocking agent and catalyst, and carry out the blocking reaction at 60-80℃ until the NCO mass fraction is 0. S3. Blending and Discharging: Add accurately measured functional additives and organic solvents, mix evenly, cool to below 40°C, and discharge to obtain a closed polyurethane prepolymer; S4. Mix the closed polyurethane prepolymer from S3 with the amine curing agent at a mass ratio of 100:(8-14) until homogeneous. Discharge the mixture to obtain the temperature-regulating high-solids closed polyurethane resin product.