Polyurethane material for extremely cold resistant tire and preparation method thereof

Abstract

The invention discloses a polyurethane material for an extremely cold resistant tire and a preparation method thereof, and belongs to the technical field of polyurethane, the polyurethane material comprises the following raw materials by mass: 50-60 parts of polyether polyol, 8-15 parts of aromatic diisocyanate, 1-3 parts of an amine chain extender and 3-6 parts of polyether modified fluorinated POSS. According to the polyether modified fluorinated POSS, polyether chain segments and perfluoroalkyl chain segments are introduced to the surfaces of POSS particles, and the perfluoroalkyl chain segments can be inserted among molecular chain segments of a polyurethane material, so that molecular chain entanglement of soft segments is reduced, the low-temperature fluidity is improved, water erosion can be reduced, and the service life is prolonged; the introduction of the polyether chain segment can improve the compatibility and dispersity of the fluorinated POSS in the polyurethane material, and the flexibility of the polyether chain segment cooperates with the rigid nano-plasticizing effect of the fluorinated POSS, so that the glass-transition temperature of the polyurethane material can be reduced, and the cold resistance of the polyurethane material is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethanes, and particularly relates to a polyurethane material for extremely cold-resistant tires and a preparation method thereof. Background Art

[0002] Polyurethane elastomer is the most important one among polyurethane materials, also known as polyurethane rubber or liquid rubber, and is a kind of elastomeric polymer material containing urethane groups in the molecular chain. Polyurethane elastomer not only has the high elasticity of rubber, but also has the high strength of plastic, and at the same time has excellent wear resistance, high shock absorption capacity, good oil resistance and resistance to a variety of solvents, and is widely used in many industries such as aerospace, ships, automobiles, medical devices, sports goods and construction.

[0003] Relying on the unique properties of polyurethane elastomer and based on the advantages of using liquid rubber processing technology and the high wear resistance of polyurethane materials, polyurethane materials have gradually replaced rubber and are applied to the production and manufacturing of tires.

[0004] Polyurethane materials can be further divided into millable polyurethane, thermoplastic polyurethane and cast polyurethane. Among them, cast polyurethane has better comprehensive performance than the other two polyurethane materials. Its chemical cross-linked structure can endow it with higher heat resistance, reduce the internal heat generation under high-speed operation, and can effectively avoid the problem of thermal degradation. At the same time, the cast polyurethane material is formed by pouring and curing liquid raw materials, with high raw material utilization rate, suitable for large-scale production, simple process in manufacturing large-volume and some special-shaped structure tires such as solid tires, and firmly bonded to the metal skeleton, with high load-bearing capacity.

[0005] However, compared with thermoplastic polyurethane, cast polyurethane material has high low-temperature brittleness. Under extremely low temperature or long-term low-temperature exposure, it may lead to a decrease in wear resistance, aggravate material fatigue, and shorten the service life. Especially when some vehicles such as military off-road vehicles need to operate in extremely cold regions, the dynamic stability of tires prepared with cast polyurethane will decrease. Summary of the Invention

[0006] The purpose of the present invention is to provide a polyurethane material for extremely cold-resistant tires and a preparation method thereof, so as to solve the problem that the poor low-temperature performance of polyurethane materials limits their application as tire raw materials in extremely cold regions.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] In the first aspect, the present invention provides a polyurethane material for extremely cold-resistant tires, comprising the following raw materials in parts by mass:

[0009] 50 - 60 parts of polyether polyol;

[0010] 8 - 15 parts of aromatic diisocyanate;

[0011] 1 - 3 parts of amine chain extender;

[0012] 3 - 6 parts of polyether - modified fluorinated POSS.

[0013] Preferably, the polyether - type polyol includes one or a combination of more than one of tetrahydrofuran ether diol, tetrahydrofuran - propylene oxide copolymer diol, and polypropylene oxide diol.

[0014] Preferably, the aromatic diisocyanate includes one or a combination of more than one of toluene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, and p - phenylene diisocyanate.

[0015] Preferably, the amine chain extender includes one or a combination of more than one of 3,3'-dichloro - 4,4'-diaminodiphenylmethane, 3,5 - dimethylthiotoluenediamine, 3,5 - diethyltoluenediamine, and 4,4'-methylene - bis(3 - chloro - 2,6 - diethylaniline).

[0016] By adopting the above - mentioned technical solution, first, by optimizing the raw material composition of the polyurethane material, a polyurethane material matrix that can adapt to low - temperature environments is obtained. Specifically, general cast polyurethane materials are polyester - type polyurethanes, which are brittle at low temperatures. In the present invention, polyether - type polyols are selected. The molecular chain of polyether - type polyols is mainly composed of ether bonds. The cohesive energy of ether bonds is relatively low, and they have good flexibility and a low glass transition temperature. Therefore, they have better low - temperature performance. And aromatic diisocyanates are also selected to react with polyether - type polyols. The molecular structure of aromatic diisocyanates contains rigid aromatic rings, which can help the prepared polyurethane material maintain good mechanical properties at low temperatures. The present invention uses the flexible chain segments contained in polyether - type polyols to lower the glass transition temperature of the polyurethane material, and the rigid hard segments and hydrogen - bond network of aromatic diisocyanates to maintain strength. The two work together to obtain a polyurethane matrix material with certain cold resistance.

[0017] However, at the same time, the high flexibility of the molecular chain of polyether - type polyols also leads to insufficient overall rigidity. Even under the regulation of aromatic diisocyanates, it is difficult to reach the mechanical strength of polyester - type polyurethane materials, and the high - temperature resistance also decreases. Therefore, this is also the reason for the commonly used polyester - type polyurethane materials at present.

[0018] To solve this problem, the present invention also adds polyether - modified fluorinated POSS to the polyurethane material. Cage - type polyhedral oligomeric silsesquioxane is an organic - inorganic hybrid material. Its inorganic rigid cage - type structure can, on the one hand, improve the overall heat resistance of the material, and on the other hand, can act as physical cross - linking points to improve the mechanical strength of the material, and can make up for the strength decline caused by polyether - type polyols.

[0019] The nano - size of polyether - modified fluorinated POSS can promote the ordered arrangement of hard and soft segments, thereby reducing the phase - separation defects in polyurethane materials. Under low - temperature conditions, the stress inside the polyurethane material can also be evenly dispersed. The fluorinated alkyl chain segments contained therein have low surface energy and high flexibility of the polymer chain. Interspersed in the polyether soft segments of the polyurethane material, they can greatly reduce the entanglement between molecular chains, thereby enhancing the movement ability of the molecular segments of the polyurethane material at low temperature and optimizing the low - temperature fluidity. At the same time, the fluorinated alkyl chain segments can form a dense hydrophobic layer on the surface of the obtained polyurethane material, thereby reducing the intrusion of moisture. On the one hand, it can reduce the impact of water freezing on the strength of the polyurethane material in a cold environment; on the other hand, it can reduce the hydrolysis problem of the ether bonds contained in the polyurethane material, thereby extending the service life of the obtained polyurethane material during tire application.

[0020] Moreover, the fluorinated POSS is dispersed in the matrix of the polyurethane material as a nano - filler, and can restrict the slippage of molecular chains through physical cross - linking, thereby inhibiting brittle fracture at low temperature and improving the impact resistance of the polyurethane material at low temperature.

[0021] However, the fluorinated alkyl chain segments have high hydrophobicity, and in polar polyurethane materials, the poor dispersibility will be caused by the polarity difference. The fluorinated chain segments are also prone to migrate to the material surface, weakening the regulating effect of the cage - type polyhedral oligomeric silsesquioxane on phase separation. Therefore, the present invention further modifies the fluorinated POSS with polyether.

[0022] After being modified with polyether, the fluorinated POSS has a similar form with the matrix of the polyurethane material. There is good compatibility between the polyether and the polyether chain segments in the polyurethane material. The polyether - modified fluorinated POSS particles can be anchored through hydrogen bonds or covalent bonds, thereby improving the dispersibility of POSS in the polyurethane material and forming a uniformly dispersed nano - composite structure, thus avoiding the agglomeration problem of physical blending. At the same time, the increased polarity of the polyether modification can neutralize the hydrophobicity of the fluorinated POSS, thereby achieving a balance between mechanical properties and hydrophobic properties and improving the mechanical properties of the material while resisting moisture erosion.

[0023] At the same time, for the fluorinated POSS modified by polyether, the flexibility of the polyether chain segments grafted on the surface of the POSS particles can synergistically enhance the nano - plasticization effect of the cage - type polyhedral oligomeric silsesquioxane, reducing the overall glass - transition temperature of the polyurethane material and further improving the cold resistance of the polyurethane material. The introduction of the polyether chain segments can also help to form reversible hydrogen bonds between the cage - type polyhedral oligomeric silsesquioxane and the polyurethane material, so that the obtained polyurethane material can also maintain elasticity under low - temperature conditions, improving the cold resistance of the polyurethane material.

[0024] Preferably, the raw materials of the polyether-modified fluorinated POSS include mercapto-POSS, polyether acrylate, and perfluoroalkyl acrylate compound with a mass ratio of 1:(0.6-0.8):(0.1-0.2).

[0025] Preferably, the polyether acrylate includes one or a combination of more of polyethylene glycol monomethacrylate and polytetrahydrofuran acrylate.

[0026] Preferably, the perfluoroalkyl acrylate compound includes one or a combination of more of 2-(perfluorobutyl)ethyl methacrylate, perfluorohexylethyl methacrylate, perfluorooctylethyl acrylate, and 2-(perfluorodecyl)ethyl methacrylate.

[0027] By adopting the above technical solution, in the polyether-modified fluorinated POSS of the present invention, polyether acrylate and perfluoroalkyl acrylate compound are used to introduce polyether chain segments and perfluoroalkyl chain segments on the surface of POSS particles respectively. The perfluoroalkyl chain segments can intersperse between the molecular chain segments of the polyurethane material, thereby reducing the molecular chain entanglement of the soft segments, enhancing the molecular chain segment movement ability of the polyurethane material at low temperature, improving the low-temperature impact performance of the polyurethane material, and also reducing the intrusion of moisture, avoiding the hydrolysis of the polyether chain segments, and improving the service life; the introduction of the polyether chain segments can improve the compatibility and dispersibility of the fluorinated POSS in the polyurethane material, and enhance the low-temperature performance of the material by forming reversible hydrogen bonds with the polar groups in the polyurethane material. The flexibility of the polyether chain segments cooperates with the rigid nano-plasticizing effect of the fluorinated POSS to help reduce the glass transition temperature of the polyurethane material and further enhance the cold resistance of the polyurethane material.

[0028] Preferably, the polyether-modified fluorinated POSS is prepared according to the following method:

[0029] Preparation of mercapto-POSS: Octavinyl polyhedral oligomeric silsesquioxane and dithiol are dissolved in a solvent. A photoinitiator is added to the obtained dithiol solution. After stirring and mixing, an octavinyl polyhedral oligomeric silsesquioxane solution is added, and the mixture is stirred and reacted for 30-60 min. After precipitation, centrifugation, washing, and drying, mercapto-POSS is obtained;

[0030] Preparation of polyether-modified fluorinated POSS: Mercapto-POSS is dissolved in a solvent, a photoinitiator is added, and the mixture is stirred and mixed. Then, polyether acrylate and perfluoroalkyl acrylate compound are added, and the mixture is stirred and reacted for 30-60 min. Finally, after filtration, rotary evaporation, precipitation, centrifugation, washing, and drying, polyether-modified fluorinated POSS is obtained.

[0031] Preferably, the mass ratio of octavinyl polyhedral oligomeric silsesquioxane to dithiol is 1:(2.8-3); the dithiol includes one or a combination of more of ethanedithiol, 1,3-propanedithiol, and 1,4-butanedithiol.

[0032] Preferably, the photoinitiator includes one or a combination of more than one of photoinitiator 1173, photoinitiator 819, and photoinitiator 651.

[0033] Preferably, during the preparation of thiolated POSS, the addition amount of the photoinitiator is 2-3% of the mass of octavinyl polyhedral oligomeric silsesquioxane.

[0034] Preferably, during the preparation of polyether-modified fluorinated POSS, the addition amount of the photoinitiator is 0.5-2% of the mass of thiolated POSS.

[0035] Preferably, the solvent includes one or a combination of more than one of tetrahydrofuran, dichloromethane, dimethylformamide, and ethyl acetate.

[0036] By adopting the above technical solution, octavinyl polyhedral oligomeric silsesquioxane is first thiolated to introduce thiol groups on the surface of POSS as active reaction sites for subsequent grafting reactions. Further, polyether acrylate and perfluoroalkyl acrylate compounds are added to the thiolated POSS solution and react and connect with the thiol under the action of a photoinitiator. By controlling the addition amounts of the added polyether acrylate and perfluoroalkyl acrylate compounds, the contents of polyether chain segments and perfluoro chain segments grafted on the surface of POSS particles are adjusted to obtain polyether-modified fluorinated POSS with a balanced hydrophobicity and compatibility, thereby helping to improve the cold resistance of polyurethane materials.

[0037] In a second aspect, the present invention provides a preparation method for a polyurethane material for an extremely cold-resistant tire, including the following process steps:

[0038] S1. Polyether-modified fluorinated POSS is added to polyether polyol. After vacuum dehydration, the temperature is adjusted to 60-70°C, and aromatic diisocyanate is added. Stir for 30-40 min under a nitrogen atmosphere, then raise the temperature to 80-85°C and stir and react for 1-2 h to obtain a prepolymer.

[0039] S2. An amine chain extender is added to the prepolymer and stirred for 1-2 min. The resulting reactant is transferred to a preheated mold and cured under pressure at 120-140°C for 20-40 min, then cured at 80-90°C for 10-12 h, and finally cured at room temperature for 5-7 d to obtain the product.

[0040] The beneficial effects of the present invention:

[0041] 1. The polyurethane material for extremely cold-resistant tires of the present invention is prepared by reacting polyether polyol and aromatic diisocyanate. The flexible chain segments contained in the polyether polyol can be used to reduce the glass transition temperature of the polyurethane material, while the rigid hard segments and hydrogen bond network of the aromatic diisocyanate can maintain the strength. Through the synergy of the two, a polyurethane matrix material with certain cold resistance is obtained.

[0042] 2. The polyurethane material for extremely cold-resistant tires of the present invention also contains polyether-modified fluorinated POSS, which can compensate for the strength decline problem caused by using polyether polyol as the raw material. Polyether chains and perfluoroalkyl chains are introduced on the surface of POSS particles. The perfluoroalkyl chains can penetrate between the molecular chain segments of the polyurethane material, reduce the entanglement of the molecular chains of the soft segments, and also reduce the intrusion of moisture, thereby improving the service life. The introduction of polyether chains can improve the compatibility and dispersibility of fluorinated POSS in the polyurethane material. Through the synergy of the two, polyether-modified fluorinated POSS with a balanced hydrophobicity and compatibility is obtained, which helps to improve the cold resistance of the polyurethane material. Specific embodiments

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0044] Preparation examples

[0045] Preparation example 1, a polyether-modified fluorinated POSS, is prepared according to the following method:

[0046] Preparation of mercapto-functionalized POSS: Take 10 g of octavinyl polyhedral oligomeric silsesquioxane and 29 g of ethanedithiol and dissolve them in 100 mL of tetrahydrofuran and 58 mL of tetrahydrofuran respectively. Add 0.3 g of photoinitiator 1173 to the obtained ethanedithiol solution, stir and mix, then add the octavinyl polyhedral oligomeric silsesquioxane solution, and stir and react for 40 min. After precipitation, centrifugation, washing and drying, mercapto-functionalized POSS is obtained;

[0047] Preparation of polyether-modified fluorinated POSS: Take 10 g of the above-obtained mercapto-functionalized POSS and dissolve it in 80 mL of tetrahydrofuran. Add 0.1 g of photoinitiator 1173, stir and mix, then add 7 g of polyethylene glycol monomethacrylate and 1.5 g of perfluorooctylethyl acrylate, stir and react for 50 min. Finally, after filtration, rotary evaporation, precipitation, centrifugation, washing and drying, polyether-modified fluorinated POSS is obtained.

[0048] Preparation Example 2, a polyether-modified fluorinated POSS, which is different from Preparation Example 1 only in that the addition amount of polyethylene glycol monomethacrylate is 6 g; the addition amount of perfluorooctylethyl acrylate is 2 g.

[0049] Preparation Example 3, a polyether-modified fluorinated POSS, which is different from Preparation Example 1 only in that the addition amount of polyethylene glycol monomethacrylate is 8 g; the addition amount of perfluorooctylethyl acrylate is 1 g.

[0050] Preparation Example 4, a polyether-modified fluorinated POSS, which is different from Preparation Example 1 only in that the addition amount of perfluorooctylethyl acrylate is 0.5 g.

[0051] Preparation Example 5, a polyether-modified fluorinated POSS, which is different from Preparation Example 1 only in that the addition amount of perfluorooctylethyl acrylate is 3 g.

[0052] Preparation Example 6, a polyether-modified POSS, which is different from Preparation Example 1 only in that perfluorooctylethyl acrylate is not added.

[0053] Preparation Example 7, a polyether-modified fluorinated POSS, which is different from Preparation Example 1 only in that the addition amount of polyethylene glycol monomethacrylate is 4 g.

[0054] Preparation Example 8, a polyether-modified fluorinated POSS, which is different from Preparation Example 1 only in that the addition amount of polyethylene glycol monomethacrylate is 10 g.

[0055] Preparation Example 9, a fluorinated POSS, which is different from Preparation Example 1 only in that polyethylene glycol monomethacrylate is not added.

[0056] Examples

[0057] Example 1, a polyurethane material for ultra-cold-resistant tires, is prepared according to the following process steps:

[0058] S1. Add 4 parts of the polyether-modified fluorinated POSS prepared in Preparation Example 1 to 56 parts of tetrahydrofuran ether glycol. After vacuum dehydration, adjust the temperature to 65 °C, add 12 parts of toluene diisocyanate, stir for 30 min under a nitrogen atmosphere, then raise the temperature to 80 °C and stir and react for 2 h to obtain a prepolymer;

[0059] S2. Add 2 parts of 3,3'-dichloro-4,4'-diaminodiphenylmethane to the prepolymer, stir for 1 min, transfer the obtained reactant to a preheated mold, press and cure at 120 °C for 30 min, then cure at 80 °C for 12 h, and finally cure at room temperature for 7 d to obtain

[0060] Example 2 and Example 3, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the raw material ratio is adjusted, as shown in Table 1 specifically:

[0061] Table 1 Formulation Table of Examples 1 - 3

[0062] Example 1 Example 2 Example 3 Tetrahydrofuran ether diol / parts 56 50 60 Polyether modified fluorinated POSS / parts 4 3 6 Toluene diisocyanate / parts 12 8 15 3,3'-Dichloro-4,4'-diaminodiphenylmethane / parts 2 1 3

[0063] Example 4, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the polyether-modified fluorinated POSS prepared in Preparation Example 2 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0064] Example 5, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the polyether-modified fluorinated POSS prepared in Preparation Example 3 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0065] Example 6, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the polyether-modified fluorinated POSS prepared in Preparation Example 4 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0066] Example 7, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the polyether-modified fluorinated POSS prepared in Preparation Example 5 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0067] Example 8, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the polyether-modified fluorinated POSS prepared in Preparation Example 7 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0068] Example 9, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the polyether-modified fluorinated POSS prepared in Preparation Example 8 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0069] Comparative Example

[0070] Comparative Example 1, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the addition amount of the polyether-modified fluorinated POSS prepared in Preparation Example 1 is 1 part.

[0071] Comparative Example 2, a polyurethane material for extremely cold-resistant tires, which is only different from Example 1 in that the addition amount of the polyether-modified fluorinated POSS prepared in Preparation Example 1 is 8 parts.

[0072] Comparative Example 3, a polyurethane material for extremely cold-resistant tires, is different from Example 1 only in that the polyether-modified POSS prepared in Preparation Example 6 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0073] Comparative Example 4, a polyurethane material for extremely cold-resistant tires, is different from Example 1 only in that the fluorinated POSS prepared in Preparation Example 9 is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0074] Comparative Example 5, a polyurethane material for extremely cold-resistant tires, is different from Example 1 only in that octavinyl polyhedral oligomeric silsesquioxane is used to replace the polyether-modified fluorinated POSS prepared in Preparation Example 1 in equal amounts.

[0075] Comparative Example 6, a polyurethane material for extremely cold-resistant tires, is different from Example 1 only in that the polyether-modified fluorinated POSS prepared in Preparation Example 1 is not added.

[0076] Performance detection test

[0077] 1. Strength test: According to the relevant records in GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber" and GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trousers, right-angle and crescent specimens)", the tensile strength and trouser tear strength of the polyurethane materials obtained in the examples and comparative examples at room temperature were tested.

[0078] 2. Cold resistance test: The polyurethane material specimens obtained in the examples and comparative examples were treated under the cyclic conditions of -45°C to -35°C for 12 h, and then according to the test method in Test 1, the tensile strength and trouser tear strength of the specimens after low-temperature cycling were tested.

[0079] The above test results are shown in Table 2:

[0080] Table 2 Test results of performance detection

[0081]

[0082] According to Table 2, in combination with Example 1, Example 6, Example 7 and Comparative Example 3, it can be seen that the tensile strength and trouser tear strength of Example 6, Example 7 and Comparative Example 3 all decreased after low-temperature cycling, indicating that the cold resistance of the polyurethane materials obtained in Example 6, Example 7 and Comparative Example 3 decreased. The reason is that the only difference between Example 6, Example 7 and Comparative Example 3 compared with Example 1 is that the content of the perfluoroalkyl chain segment in the polyether-modified fluorinated POSS was adjusted. Among them, the addition amount of the perfluoroalkyl chain segment was reduced in Example 6, and it was difficult to improve the entanglement problem between the soft segment molecular chains in the polyurethane material. Coupled with the strength decrease caused by water erosion under low-temperature cycling, the cold resistance of the obtained polyurethane material decreased; the POSS particles added in Comparative Example 3 did not introduce perfluoroalkyl chain segments on the surface, and the performance decreased more significantly; in Example 7, the introduced perfluoroalkyl chain segment was increased, which would lead to an increase in hydrophobicity and a polarity imbalance with the polyether chain segment, thereby reducing the low-temperature performance of the material.

[0083] In combination with Example 1, Example 8, Example 9 and Comparative Example 4, it can be seen that the tensile strength and trouser tear strength of Example 8, Example 9 and Comparative Example 4 all decreased after low-temperature cycling, indicating that the cold resistance of the polyurethane materials obtained in Example 8, Example 9 and Comparative Example 4 decreased. The reason is that the only difference between Example 8, Example 9 and Comparative Example 4 compared with Example 1 is that the content of the polyether chain segment in the polyether-modified fluorinated POSS was adjusted. Among them, the addition amount of the polyether chain segment was reduced in Example 8, which would lead to a decrease in the dispersibility and interfacial compatibility of the polyether-modified fluorinated POSS in the polyurethane material, and the improvement effect on cold resistance decreased. Moreover, the tensile strength and trouser tear strength of Example 8 at room temperature also decreased compared with Example 1 because the decrease in the polyether chain segment would lead to a decrease in the content of reversible hydrogen bonds formed between the polyether-modified fluorinated POSS and the polyurethane material, which would affect the strength of the obtained polyurethane material; the POSS particles added in Comparative Example 4 did not introduce polyether chain segments on the surface, and the performance decreased more significantly; in Example 9, the introduced polyether chain segment was increased, which would increase the crosslinking density formed with the polyurethane material, and instead was not conducive to the improvement of the low-temperature fluidity of the molecular chain by the polyether-modified fluorinated POSS.

[0084] Combined with Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 5 and Comparative Example 6, it can be seen that the tensile strength and trouser tear strength of Comparative Example 1, Comparative Example 2, Comparative Example 5 and Comparative Example 6 all decreased after low-temperature cycling. The reason is that the addition amount of polyether-modified fluorinated POSS was changed in Comparative Example 1 and Comparative Example 2. Among them, the addition amount of polyether-modified fluorinated POSS was reduced in Comparative Example 1, so the effect of polyether-modified fluorinated POSS on improving the strength of the polyurethane material itself decreased, and the effect of promoting the ordered arrangement of the hard and soft segments of the polyurethane material decreased, which would lead to a reduction in the mechanical strength of the material. In Comparative Example 6, polyether-modified fluorinated POSS was not added, and the performance degradation was more obvious. In Comparative Example 2, the addition amount of polyether-modified fluorinated POSS was increased, and polyether-modified fluorinated POSS would excessively participate in the cross-linking reaction process of the polyurethane material, which was not conducive to the perfluoroalkyl chain segment weakening the binding force between the soft segment molecular chains, thereby reducing the low-temperature performance of the polyurethane material. In Comparative Example 5, perfluoroalkyl acrylate and polyether chain segments were not introduced on the surface of the added POSS. Correspondingly, the improvement effect on the polyurethane material decreased.

[0085] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0086] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polyurethane material for ultra-cold resistant tires, characterized in that, It comprises raw materials in the following parts by mass: 50 - 60 parts of polyether polyol; 8 - 15 parts of aromatic diisocyanate; 1 - 3 parts of amine chain extender; 3 - 6 parts of polyether-modified fluorinated POSS.

2. The polyurethane material for an extremely cold-resistant tire according to claim 1, wherein The raw materials of the polyether-modified fluorinated POSS include mercapto-POSS, polyether acrylate and perfluoroalkyl acrylate compound with a mass ratio of 1:(0.6 - 0.8):(0.1 - 0.2).

3. The polyurethane material for extremely cold-resistant tires according to claim 2, characterized in that, The polyether acrylate includes one or a combination of more than one of polyethylene glycol monomethacrylate and polytetrahydrofuran acrylate.

4. The polyurethane material for an extremely cold-resistant tire according to claim 2, characterized in that, The perfluoroalkyl acrylate compound includes one or a combination of more than one of 2-(perfluorobutyl)ethyl methacrylate, perfluorohexylethyl methacrylate, perfluorooctylethyl acrylate and 2-(perfluorodecyl)ethyl methacrylate.

5. The polyurethane material for ultra-cold resistant tires according to claim 2, characterized in that, The polyether-modified fluorinated POSS is prepared by the following method: Preparation of mercapto-POSS: Octavinyl polyhedral oligomeric silsesquioxane and dithiol are dissolved in a solvent. A photoinitiator is added to the obtained dithiol solution. After stirring and mixing, an octavinyl polyhedral oligomeric silsesquioxane solution is added, and the mixture is stirred and reacted for 30 - 60 min. Mercapto-POSS is obtained through precipitation, centrifugation, washing and drying. Preparation of polyether-modified fluorinated POSS: Mercapto-POSS is dissolved in a solvent, a photoinitiator is added, and the mixture is stirred and mixed. Then, polyether acrylate and perfluoroalkyl acrylate compound are added, and the mixture is stirred and reacted for 30 - 60 min. Finally, polyether-modified fluorinated POSS is obtained through filtration, rotary evaporation, precipitation, centrifugation, washing and drying.

6. The polyurethane material for ultra-cold resistant tires according to claim 5, characterized in that, The mass ratio of the octavinyl polyhedral oligomeric silsesquioxane to the dithiol is 1:(2.8 - 3); the dithiol includes one or a combination of more than one of ethanedithiol, 1,3-propanedithiol and 1,4-butanedithiol.

7. The polyurethane material for ultra-cold resistant tires according to claim 1, characterized in that, The polyether polyol includes one or a combination of more than one of tetrahydrofuran ether diol, tetrahydrofuran-oxide propylene copolymer diol and polyoxypropylene diol.

8. The polyurethane material for an extremely cold-resistant tire according to claim 1, characterized in that, The aromatic diisocyanate includes one or a combination of more than one of toluene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate and p-phenylene diisocyanate.

9. The polyurethane material for an extremely cold-resistant tire according to claim 1, wherein The amine chain extender includes one or a combination of more than one of 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,5-dimethylthiotoluenediamine, 3,5-diethyltoluenediamine and 4,4'-methylene-bis(3-chloro-2,6-diethylaniline).

10. A method for preparing a polyurethane material for an extremely cold-resistant tire according to any one of claims 1 to 9, characterized in that, It includes the following technological steps: S1. Polyether-modified fluorinated POSS is added to the polyether polyol. After vacuum dehydration, the temperature is adjusted to 60 - 70 °C, and aromatic diisocyanate is added. The mixture is stirred in a nitrogen atmosphere for 30 - 40 min, then the temperature is raised to 80 - 85 °C, and the mixture is stirred and reacted for 1 - 2 h to obtain a prepolymer. S2. An amine chain extender is added to the prepolymer, and the mixture is stirred for 1 - 2 min. The obtained reactant is transferred to a preheated mold, and is pressure-cured at 120 - 140 °C for 20 - 40 min, then cured at 80 - 90 °C for 10 - 12 h, and finally cured at room temperature for 5 - 7 d to obtain the product.

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