High-temperature-resistant organic silicon modified polyurethane resin as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polyurethane, and particularly relates to high-temperature-resistant organic silicon modified polyurethane resin as well as a preparation method and application thereof. The high-temperature-resistant organic silicon modified polyurethane resin has the following chemical structure: # imgabs0 #. The preparation method of the high-temperature-resistant organic silicon modified polyurethane resin comprises the following steps: putting polyester polyol into a reaction container under the protection of nitrogen, stirring and heating, carrying out vacuum dehydration and degassing, detecting moisture, cooling, adding diisocyanate, a catalyst and a plasticizer, and stirring and reacting to obtain a hydroxyl-terminated polyurethane prepolymer; and adding isocyanate silane into the hydroxyl-terminated polyurethane prepolymer, and carrying out stirring reaction at 80-85 DEG C for 2-3 hours to obtain the high-temperature-resistant organic silicon modified polyurethane resin. According to the preparation method of the high-temperature-resistant organic silicon modified polyurethane resin, the high-temperature-resistant organic silicon modified polyurethane resin is used for preparing a curing sealant, the thermal decomposition temperature of the material is increased, and the high temperature resistance is remarkably enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethane, and in particular relates to a high-temperature resistant organosilicon-modified polyurethane resin and a preparation method and application thereof. Background Art

[0002] Polyurethane resins are derived from the polymerization of polyols and isocyanates. Properties such as wear resistance, chemical resistance, and lightweight sound and thermal insulation can be customized by adjusting the raw material ratio, adding additives (such as flame retardants and fillers), or modifying them (such as epoxy resins, silanes, and nanomaterials). Their adjustable properties and diverse applications make them a polymer material with great innovative potential. Polyurethane resins are categorized into polyether polyurethane resins and polyester polyurethane resins. Silane-modified polyether resins (MS resins) are widely used due to their excellent environmental performance, weather resistance, and adhesion properties, as well as their low viscosity, fast curing, and ease of application. However, MS resins have poor temperature resistance, making them difficult to use in high-temperature environments. Compared to polyether polyurethane resins, polyester polyurethane resins offer relatively better heat resistance, allowing for higher application temperatures.

[0003] CN116239762A discloses a polyester-based MS adhesive base resin and a preparation method thereof. The polyester-type base resin is obtained by mixing a diepoxy-terminated polyester with an aminosilane. The polyester-type base resin has high heat resistance and stability, but the mechanical properties of the base resin are poor. Aminopropylheptyl cage-shaped polysilsesquioxane and a cross-linkable polyolefin elastomer need to be added to improve the mechanical properties. The aminopropylheptyl cage-shaped polysilsesquioxane is relatively expensive, and the cross-linkable polyolefin elastomer requires ethylene and is prepared at 120°C, which is somewhat dangerous.

[0004] CN109867763A discloses a preparation process and application of a weak solvent, high temperature resistant, yellowing resistant and environmentally friendly synthetic leather polyurethane resin. The polyurethane resin is synthesized by diisocyanate and terminal hydroxyl polymer polyol, and the high heat resistance of polycarbonyl polyol and the low crystallinity of polyether polyol are combined to achieve the effects of high temperature resistance and yellowing resistance. However, its heat resistance temperature is 150°C, which is difficult to meet the application requirements under higher temperature conditions.

[0005] CN119307221A discloses a two-component hydrophobic and heat-resistant polyurethane potting compound and a preparation method thereof. Siloxane-modified polyether polyol is prepared by introducing a hydrophobic and heat-resistant Si-O-Si chain segment into a polyether polyol structure through acrylic bridging. However, hydroxyethyl acrylate has a special pungent odor and moderate toxicity, which limits its application in certain scenarios with high environmental and health requirements.

[0006] Existing technologies have improved the heat resistance of polyurethane resin materials to a certain extent, but the high-temperature resistance effect is limited, or there are restrictions on application scenarios, and they cannot be used for the preparation of one-component adhesives. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for preparing a high-temperature resistant silicone-modified polyurethane resin. The high-temperature resistant silicone-modified polyurethane resin is used to prepare a curing sealant, thereby increasing the thermal decomposition temperature of the material and significantly enhancing the high-temperature resistance.

[0008] The high temperature resistant silicone modified polyurethane resin has the following chemical structure: ; Among them, R1 is 、 、 or ; R2 is a polyester chain; R3 is 、 or .

[0009] The preparation method of the high-temperature resistant silicone-modified polyurethane resin comprises the following steps: adding polyester polyol into a reaction vessel protected by nitrogen, stirring and heating to 100-110°C, vacuum dehydration and degassing for 2-3 hours, detecting the moisture content to be ≤0.02%, cooling to 80-85°C, adding diisocyanate, a catalyst and a plasticizer, stirring and reacting for 2-3 hours to obtain a hydroxyl-terminated polyurethane prepolymer; and adding isocyanate silane to the hydroxyl-terminated polyurethane prepolymer, stirring and reacting at 80-85°C for 2-3 hours to obtain a high-temperature resistant silicone-modified polyurethane resin.

[0010] The functionality of the polyester polyol is 2, and the hydroxyl value is measured according to the HG / T 2709-1995 standard and is 37.4~74.8mgKOH / g. According to formula 1, the number average molecular weight can be calculated to be 1500~3000g / mol.

[0011] Formula 1.

[0012] Wherein: Mn is the number average molecular weight, OHV is the hydroxyl value of the sample, and n is the functionality of the polyester polyol. The polyester polyol is preferably one or two of PE-2515, PE-2430, PE-2520 or PE-2415.

[0013] The diisocyanate is one of toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and meta-xylylene diisocyanate (XDI).

[0014] The isocyanate silane is one of 3-isocyanate propyltrimethoxysilane, 3-isocyanate propyltriethoxysilane and α-isocyanate methyltriethoxysilane.

[0015] The catalyst is one of bismuth isooctanoate, bismuth neodecanoate and bismuth laurate, and its usage is 50-100 ppm of the total amount of polyester polyol, diisocyanate and isocyanate silane.

[0016] The plasticizer is one of diisodecyl phthalate, dioctyl phthalate and diisononyl phthalate, and its usage is 0-20% of the total mass of polyester polyol, diisocyanate and isocyanate silane.

[0017] The molar ratio of diisocyanate to polyester polyol is 1:(2~2.05).

[0018] The molar ratio of the hydroxyl-terminated polyurethane prepolymer to the isocyanate silane is 1:(2~2.05).

[0019] Application of the high-temperature resistant organosilicon-modified polyurethane resin: for preparing curing sealant.

[0020] The present invention uses polyester polyols with better heat resistance to replace traditional polyether polyols to construct a polyurethane resin matrix system; the polyol is reacted with isocyanate to prepare a polyurethane resin with a terminal group of hydroxyl rather than the traditional isocyanate group, and then the end group is modified with isocyanate silane to prepare a silicone-modified polyurethane resin. The polyurethane resin prepared by the present invention has good controllability of the polymerization reaction and is not prone to gelation. The surface of the polyurethane resin is covered with a large number of siloxane groups. After curing, a large number of Si-O-Si cross-linked structures will be formed on the surface of the adhesive layer, forming a dense inorganic protective layer network, like a layer of "ceramic armor" covering the surface of the polyurethane material. The Si-O bond energy is as high as 452kJ / mol, and its thermal decomposition temperature can be increased by about 80°C relative to the carbamate structure, thereby significantly improving the high temperature resistance of the polyurethane resin.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses polyester polyols with better heat resistance to construct the matrix, and through the innovative "terminated hydroxyl polyurethane prepolymer + isocyanate silane capping" process, introduces high bond energy siloxane groups on the resin surface. After curing, these groups form a dense Si-O-Si inorganic cross-linked network ("ceramic armor" effect), covering the surface of the polyurethane material, so that its thermal decomposition temperature can be increased by about 80°C compared with the traditional urethane structure, significantly breaking through the temperature resistance bottleneck of existing MS resins and some polyester polyurethane resins.

[0022] (2) The polyurethane resin prepared by the method of the present invention has low viscosity, good controllability of the polymerization reaction, is not prone to gelation, and is easy to operate and subsequently apply. The preparation process avoids the use of expensive cage-shaped polysilsesquioxanes and the dangers of operating under high temperature and high pressure conditions, and completely abandons harmful raw materials such as hydroxyethyl acrylate, which is irritating and moderately toxic. The production process is safer and more environmentally friendly.

[0023] (3) The present invention uses only conventional polyester polyols, diisocyanates, isocyanate silanes, catalysts, and plasticizers. The raw materials are readily available, the process steps are relatively simple, and no complex or expensive modification additives are required, effectively reducing production costs. The resulting resin is particularly suitable for preparing one-component curing sealants, meeting a wide range of application scenarios with high requirements for high temperature resistance, environmental friendliness, safety, and cost-effectiveness, such as high-temperature sealing and bonding in the automotive, electronics, aerospace, and construction fields. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to specific embodiments.

[0025] Unless otherwise specified, all raw materials used in the examples and comparative examples are commercially available.

[0026] Some of the raw materials used in the examples and comparative examples are described as follows: S303H: KANEKA MS POLYMER™ S303H silane-modified polyether resin, manufactured by KANEKA Corporation of Japan. PE-2515 (functionality 2, number-average molecular weight 1500 g / mol), prepared by polycondensation of ethylene glycol and diethylene glycol with adipic acid, produced by Shandong Yinuowei Polyurethane Co., Ltd. PE-2430 (functionality 2, number-average molecular weight 3000 g / mol), prepared by polycondensation of ethylene glycol and propylene glycol with adipic acid, produced by Shandong Yinuowei Polyurethane Co., Ltd. PE-2520 (functionality 2, number-average molecular weight 2000 g / mol), prepared by polycondensation of ethylene glycol and diethylene glycol with adipic acid, available from Shandong Yinuowei Polyurethane Co., Ltd. PE-2415 (functionality 2, number-average molecular weight 1500 g / mol), prepared by polycondensation of ethylene glycol and propylene glycol with adipic acid, produced by Shandong Yinuowei Polyurethane Co., Ltd. INOVOL C220 (functionality 2, number-average molecular weight 2000 g / mol) is produced by polymerization of propylene glycol with propylene oxide. Shandong INOVOL New Materials Co., Ltd.

[0027] Example 1 The high temperature resistant silicone modified polyurethane resin has the following chemical structure:

[0028] ,in" ” is a PE-2520 polyester chain.

[0029] The method for preparing the high-temperature resistant silicone-modified polyurethane resin comprises the following steps: 405g PE-2520 was added to a nitrogen-protected reaction vessel, heated to 105°C, stirred for 2.5h until the moisture content was below 0.02%, cooled to 82°C, and 25g 4,4'-diphenylmethane diisocyanate, 0.07g bismuth laurate and 141g dioctyl phthalate were added to react until the wave number in the infrared spectrum was 1720cm -1 The -NCO characteristic peak disappears, and a hydroxyl-terminated polyurethane prepolymer is obtained; 50 g of 3-isocyanatepropyltriethoxysilane is added to the prepolymer, and stirring is continued at 82° C. for 2.5 hours to obtain a high-temperature resistant silicone-modified polyurethane resin material.

[0030] Example 2 The high temperature resistant silicone modified polyurethane resin has the following chemical structure:

[0031] ,in" ” is a PE-2515 polyester chain.

[0032] The method for preparing the high-temperature resistant silicone-modified polyurethane resin comprises the following steps: 300g PE-2515 was added to a nitrogen-protected reaction vessel, heated to 100°C, stirred for 2h until the moisture content was below 0.02%, cooled to 80°C, and 17.4g toluene diisocyanate and 0.018g bismuth neodecanoate were added to react until the wave number in the infrared spectrum reached 1720cm -1 The characteristic peak of -NCO disappears, and a hydroxyl-terminated polyurethane prepolymer is obtained; 42 g of 3-isocyanatepropyltrimethoxysilane is added to the prepolymer, and stirring is continued at 80° C. for 2 h to obtain a high-temperature resistant silicone-modified polyurethane resin material.

[0033] Example 3 The high temperature resistant silicone modified polyurethane resin has the following chemical structure:

[0034] ,in" ” is a PE-2430 polyester chain.

[0035] The method for preparing the high-temperature resistant silicone-modified polyurethane resin comprises the following steps: 307.5 g of PE-2430 was added to a nitrogen-protected reaction vessel, heated to 110 ° C, stirred for 3 h until the moisture content was below 0.02%, cooled to 85 ° C, and 8.4 g of hexamethylene diisocyanate, 0.034 g of bismuth neodecanoate and 54.49 g of diisodecyl phthalate were added to react until the wave number in the infrared spectrum was 1720 cm -1 The characteristic peak of -NCO disappears, and a hydroxyl-terminated polyurethane prepolymer is obtained; 21.9 g of α-isocyanate methyltriethoxysilane is added to the prepolymer, and stirring is continued at 85° C. for 3 hours to obtain a high-temperature resistant silicone-modified polyurethane resin material.

[0036] Example 4 The high temperature resistant silicone modified polyurethane resin has the following chemical structure:

[0037] ,in" ” is the polyester chain of PE-2515 and PE-2415.

[0038] The method for preparing the high-temperature resistant silicone-modified polyurethane resin comprises the following steps: 150g PE-2415 and 150g PE-2515 were added to a nitrogen-protected reaction vessel, heated to 110°C, stirred for 2.5h until the moisture content was below 0.02%, cooled to 80°C, and 18.8g xylylene diisocyanate, 0.040g bismuth isooctanoate and 52.9g diisononyl phthalate were added to react until the wave number in the infrared spectrum was 1720cm -1 The characteristic peak of -NCO disappears, and a hydroxyl-terminated polyurethane prepolymer is obtained; 41 g of 3-isocyanatepropyltrimethoxysilane is added to the prepolymer, and stirring is continued at 83° C. for 2.5 hours to obtain a high-temperature resistant silicone-modified polyurethane resin material.

[0039] Comparative Example 1 The difference between this comparative example and Example 1 is that the polyester polyol PE-2520 in Example 1 is replaced by the polyether polyol INOVOL C220.

[0040] Comparative Example 2 This comparative example differs from Example 1 in that 3-isocyanatepropyltriethoxysilane is not added.

[0041] Comparative Example 3 This comparative example differs from Example 1 in that no 4,4'-diphenylmethane diisocyanate is added.

[0042] Comparative Example 4 The difference between this comparative example and Example 1 is that the high-temperature resistant silicone-modified polyurethane resin material prepared in Example 1 is replaced by KANEKA MS POLYMER™ S303H silane-modified polyether resin produced by KANEKA Corporation of Japan.

[0043] The resins obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were used in the following applications in parts by weight: 40 parts of polyurethane resin, 20 parts of diisodecyl phthalate, 20 parts of ground calcium carbonate, 30 parts of nano-activated calcium carbonate, and 0.5 parts of UV-327 ultraviolet absorber were added one by one to a dual planetary vacuum power mixer. The stirring and dispersion switches were activated, and the mixture was heated to 110°C at high speed and then vacuumed to dehydrate. The machine was stopped when the moisture content of the material was acceptable (moisture content ≤ 0.02%). After the material was naturally cooled, 0.5 parts of vinyldimethoxymethylsilane, 2 parts of N-aminoethyl 3-aminopropylmethyldimethoxysilane, and 0.5 parts of dibutyltin dilaurate were added stepwise under nitrogen protection. The mixture was then stirred under vacuum until the mixture was uniformly mixed. Finally, the resulting sealant material was placed in aluminum film plastic bags under nitrogen protection to obtain Example Cured Sealant 1-4 and Comparative Example Cured Sealant 1-4.

[0044] The performance tests of the cured sealants 1 to 4 of the examples and the cured sealants 1 to 4 of the comparative examples were performed respectively, and the test methods were as follows: (1) Initial thermal decomposition temperature (°C), measured using a differential scanning calorimeter.

[0045] (2) Tensile strength and shear strength are tested in accordance with GB / T7124-2008; The test results are shown in Table 1.

[0046] Table 1 Performance test results

[0047] The test data in Table 1 demonstrate that the mechanical properties and high-temperature resistance of the heat-resistant organosilicon-modified polyurethane resin materials prepared in the present invention exhibit significant advantages over those in Comparative Examples 1-4. Comparing the data in Example 1 with that in Comparative Example 1 reveals that polyester polyols exhibit superior mechanical properties and high-temperature resistance compared to polyether polyols. Comparing the data in Example 1 with that in Comparative Example 2 reveals that silane groups significantly enhance the mechanical properties and high-temperature resistance of the material. Comparing the data in Example 1 with that in Comparative Example 3 reveals that carbamate groups enhance the mechanical properties and high-temperature resistance of the material.

Claims

1. A high temperature resistant silicone modified polyurethane resin, characterized by: It has the following chemical structure: ； Among them, R1 is 、 、 or ; R2 is a polyester chain; R3 is 、 or .

2. A method for preparing the high-temperature resistant organosilicon-modified polyurethane resin according to claim 1, characterized in that: The following steps are involved: The polyester polyol is placed in a nitrogen-protected reaction vessel, stirred and heated to 100-110°C, vacuum dehydrated and degassed for 2-3 hours, and after the moisture content is detected to be ≤0.02%, the temperature is lowered to 80-85°C, diisocyanate, catalyst and plasticizer are added, and the mixture is stirred and reacted for 2-3 hours to obtain a hydroxyl-terminated polyurethane prepolymer; isocyanate silane is added to the hydroxyl-terminated polyurethane prepolymer, and the mixture is stirred and reacted at 80-85°C for 2-3 hours to obtain a high-temperature resistant silicone-modified polyurethane resin.

3. The method for preparing a high-temperature resistant organosilicon-modified polyurethane resin according to claim 2, wherein: The functionality of polyester polyol is 2, and the number average molecular weight is 1500~3000g / mol.

4. The method for preparing a high-temperature resistant organosilicon-modified polyurethane resin according to claim 3, wherein: The diisocyanate is one of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate.

5. The method for preparing a high-temperature resistant organosilicon-modified polyurethane resin according to claim 4, wherein: The isocyanate silane is one of 3-isocyanate propyltrimethoxysilane, 3-isocyanate propyltriethoxysilane and α-isocyanate methyltriethoxysilane.

6. The method for preparing a high temperature resistant organosilicon modified polyurethane resin according to claim 5, wherein: The catalyst is one of bismuth isooctanoate, bismuth neodecanoate and bismuth laurate, and its usage is 50-100 ppm of the total amount of polyester polyol, diisocyanate and isocyanate silane.

7. The method for preparing a high temperature resistant organosilicon modified polyurethane resin according to claim 6, characterized in that: The plasticizer is one of diisodecyl phthalate, dioctyl phthalate and diisononyl phthalate, and its usage is 0-20% of the total mass of polyester polyol, diisocyanate and isocyanate silane.

8. The method for preparing a high temperature resistant organosilicon modified polyurethane resin according to claim 2, wherein: The molar ratio of diisocyanate to polyester polyol is 1:(2~2.05).

9. The method for preparing a high temperature resistant organosilicon modified polyurethane resin according to claim 8, wherein: The molar ratio of the hydroxyl-terminated polyurethane prepolymer to the isocyanate silane is 1:(2~2.05).

10. An application of the high temperature resistant organosilicon modified polyurethane resin according to claim 1, characterized in that: Used to prepare curing sealants.

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