Fluorosilicone modified polyurethane-based low-temperature anti-ultraviolet composite material and preparation process thereof

Abstract

The invention relates to a fluorosilicone modified polyurethane-based low-temperature anti-ultraviolet composite material, which is prepared from the following raw materials in parts by weight: 40 to 60 parts of soft segment components, 20 to 40 parts of hard segment components, 10 to 20 parts of functional side chain components, 1 to 5 parts of cross-linking agents and 0.05 to 0.1 part of catalysts, the hard segment component is prepared from 15 to 25 parts of fluorine-containing high isocyanate and 5 to 15 parts of silicon-containing chain segments; the functional side chain is prepared from the following raw materials in parts by weight: 15 to 21 parts of fluorine-containing acrylate monomer and 9 to 15 parts of silicon-containing acrylate monomer. The elongation at break of the material is gt; the tensile strength is gt; the yellowing index change value (delta Y1) lt is 31 MPa; 2.0, tensile strength retention rate gt; the mass loss rate is 80%; the anti-ultraviolet coating disclosed by the invention has good low-temperature performance, anti-ultraviolet performance and long-acting stability.

Description

Technical Field

[0001] This application relates to the field of polymer material modification technology, and in particular to a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material and its preparation process. Background Technology

[0002] Polyurethane (PU) materials are widely used due to their excellent mechanical properties, wear resistance, and designability. However, traditional polyurethane materials have significant shortcomings in extreme environments: at low temperatures, the mobility of their molecular chain segments decreases, leading to hardening and brittleness, and a sharp reduction in flexibility and elongation; under long-term ultraviolet radiation, their molecular chains (especially urethane and ether bonds) are prone to photo-oxidative degradation, resulting in yellowing, chalking, decreased mechanical properties, and shortened service life.

[0003] To address these issues, existing technologies typically employ the addition of small-molecule additives, such as plasticizers to improve low-temperature performance and UV absorbers and light stabilizers to enhance UV resistance. However, these small-molecule additives are prone to migration and precipitation, leading to rapid performance degradation and failing to meet the requirements for long-term (e.g., over 10 years) outdoor use. Furthermore, the addition of plasticizers often sacrifices the material's strength and modulus.

[0004] Therefore, developing a composite material that can fundamentally endow materials with intrinsic low-temperature resistance and UV resistance through molecular structure design, and also possess long-term stability, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention discloses a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material. Through a unique "fluorosilicone synergistic" molecular structure design, this material possesses excellent low-temperature toughness, long-lasting UV aging resistance, and high density without relying on or with minimal reliance on small molecule additives.

[0006] In a first aspect of this application, a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material is provided, comprising the following raw materials in parts by weight: 40-60 parts of soft segment component, 20-40 parts of hard segment component, 10-20 parts of functionalized side chain component, 1-5 parts of crosslinking agent, and 0.05-0.1 parts of catalyst; wherein the hard segment component comprises 15-25 parts of fluorinated high isocyanate and 5-15 parts of silicon-containing segment; wherein the raw material of the functionalized side chain component comprises 15-21 parts of fluorinated acrylate monomer and 9-15 parts of silicon-containing acrylate monomer; wherein the silicon-containing segment is selected from at least one of KH-560 and KH-550; wherein the fluorinated acrylate monomer is selected from at least one of perfluorodecyl ethyl methacrylate, trifluoroethyl methacrylate, and hexafluorobutyl methacrylate; and wherein the silicon-containing acrylate monomer is selected from at least one of trimethoxysilane methacrylate and KH-570.

[0007] By adopting the above technical solution, this application provides a fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material. Under low-temperature conditions, the elongation at break is >300%; it has good UV resistance, with a tensile strength >31MPa, a yellowing index change value (ΔY1) <2.0, and a tensile strength retention rate >80%; it also has good long-term stability, with a mass loss rate <1.0%. This may be because, on the one hand, the soft segment component and the fluorosilicone-containing hard segment component form a "fluorosilicone-soft segment" block copolymer. The low surface energy of fluorine atoms combined with the high bond energy of silicon-oxygen bonds lowers the glass transition temperature of the material, allowing the polyurethane to maintain good flexibility below -40℃; on the other hand, the rigidity of long-chain fluorine and the flexibility of short-chain fluorine in the functionalized side chain component complement each other, enhancing the low-temperature flexibility of the composite material. Fluorosilicone is grafted onto the polyurethane main chain through free radical polymerization to form a fluorosilicone side chain network. The low surface energy and high density of the fluorosilicone network prevent the propagation of surface cracks induced by ultraviolet rays and effectively inhibit the photo-oxidative degradation of polyurethane.

[0008] Optionally, the mass ratio of the fluorinated high isocyanate to the silicon-containing segment is (1.5-2.75):1.

[0009] By adopting the above technical solution and controlling the amount of fluorinated high isocyanate and silicon-containing segments according to the above mass ratio, when the mass ratio of fluorinated high isocyanate and silicon-containing segments is (1.5-2.75):1, the synergistic effect of the low surface energy of fluorine atoms and the high bond energy of silicon-oxygen bonds can ensure that the fluorinated silicon modified polyurethane-based low-temperature UV-resistant composite material maintains good flexibility under low-temperature conditions.

[0010] Optionally, the preparation of the fluorinated high isocyanate includes the following steps: a1: Under inert gas protection, toluene diisocyanate and isomeric xylene are added, stirred, and heated to 70-80℃; trimethylolpropane and ethyl acetate are added, mixed, and reacted for 3-4 hours at a reaction temperature of 70-90℃ to obtain the first prepolymer; a2: Under inert gas protection, 2,2,3,3,4,4-hexafluoro-1,5-pentanediol is added to the first prepolymer prepared in step a1, and the reaction is carried out for 2-3 hours at a temperature of 70-90℃. After cooling and drying, the fluorinated high isocyanate is obtained.

[0011] Optionally, the mass ratio of the fluorinated acrylate monomer to the silicone acrylate monomer is (1-2.33):1.

[0012] By adopting the above technical solution and adjusting the amount of fluorinated acrylate monomer and silicone acrylate monomer according to the above mass ratio, when the mass ratio of fluorinated acrylate monomer and silicone acrylate monomer is (1-2.33):1, the rigidity of long-chain fluorine and the flexibility of short-chain fluorine, combined with the high bond energy of silicon-oxygen bonds in the presence of silicone acrylate monomer, the three are synergistically matched to ensure the good low-temperature performance, UV resistance and long-term stability of fluorinated silicone modified polyurethane-based low-temperature UV-resistant composite material.

[0013] Optionally, the fluorinated acrylate monomer includes perfluorodecyl ethyl methacrylate and trifluoroethyl methacrylate; the mass ratio of perfluorodecyl ethyl methacrylate to trifluoroethyl methacrylate is (0.5-2):1.

[0014] By adopting the above technical solution and adjusting the amount of perfluorodecyl ethyl methacrylate and trifluoroethyl methacrylate according to the above mass ratio, when the mass ratio of perfluorodecyl ethyl methacrylate and trifluoroethyl methacrylate is (0.5-2):1, the rigidity of long-chain fluorine and the flexibility of short-chain fluorine complement each other, enhancing the low-temperature flexibility of the composite material.

[0015] Optionally, the preparation of the functionalized side chain includes the following steps: b1: Perfluorodecyl ethyl methacrylate, trifluoroethyl methacrylate, trimethoxysilane methacrylate and ethanol are added to a reaction flask, stirred to remove oxygen, azobisisobutyronitrile initiator is added, the temperature is raised to 60-80℃, the reaction is kept at a constant temperature for 7-9 hours, and then cooled to obtain the reaction solution. b2: Add the reaction solution obtained in step b1 to cold n-hexane, precipitate, filter, and dry to obtain the functionalized side chain.

[0016] Optionally, the mass ratio of the soft segment component to the hard segment component is (1.22-2.33):1.

[0017] By adopting the above technical solution and controlling the amount of soft segment component and hard segment component according to the above mass ratio, when the mass ratio of soft segment component and hard segment component is (1.22-2.33):1, the soft segment component and the fluorinated silicon hard segment component form a "fluorinated silicon-soft segment" block copolymer, which can ensure that the fluorinated silicon modified polyurethane-based low-temperature UV-resistant composite material maintains good flexibility under low-temperature conditions.

[0018] Optionally, the crosslinking agent is ethylene glycol diglycidyl ether; the catalyst is dibutyltin dilaurate.

[0019] In a second aspect of this application, a method for preparing the fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material described in the first aspect of this application is provided, comprising the following steps: S1: Preparation of prepolymer: Under inert gas protection, the soft segment component is vacuum dehydrated at 100-120℃ for 1-2 hours, cooled to 70-90℃, the fluorinated high isocyanate and catalyst are added, and the reaction is carried out under inert gas protection for 2-3 hours to obtain the prepolymer; S2: Hard segment chain extension and side chain branching: The temperature of the prepolymer obtained in step S1 is reduced to 50-70℃, the silicon-containing segments and the functionalized side chain components are added, and the mixture is stirred for 1-2 hours to obtain a mixture. S3: Crosslinking and curing: Add the crosslinking agent to the mixture obtained in step S2, stir evenly, pour into a mold, cure at 80-100℃ for 2-4 hours, and then cure at 100-120℃ for 4-6 hours; to obtain the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material.

[0020] In a third aspect of this application, this application provides the application of the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material described in the first aspect of this application in the preparation of waterproof materials for cold-weather outdoor equipment or buildings.

[0021] In summary, the present invention has at least one of the following beneficial technical effects: 1. This application provides a fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material. Under low-temperature conditions, the elongation at break is >300%; it has good UV resistance, with a tensile strength >31MPa, a yellowing index change value (ΔY1) <2.0, and a tensile strength retention rate >80%; it also exhibits good long-term stability with a mass loss rate <1.0%. On one hand, the soft segment component and the fluorosilicone-containing hard segment component form a "fluorosilicone-soft segment" block copolymer. The low surface energy of fluorine atoms combined with the high bond energy of silicon-oxygen bonds lowers the glass transition temperature of the material, allowing the polyurethane to maintain good flexibility below -40℃. On the other hand, the rigidity of long-chain fluorine and the flexibility of short-chain fluorine in the functionalized side chain components complement each other, enhancing the low-temperature flexibility of the composite material. Fluorosilicone is grafted onto the polyurethane main chain through free radical polymerization to form a fluorosilicone side chain network. The low surface energy and high density of the fluorosilicone network prevent the propagation of surface cracks induced by ultraviolet radiation and effectively inhibit the photo-oxidative degradation of polyurethane.

[0022] 2. This application provides an application of a fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material in the preparation of waterproof materials for cold-weather outdoor equipment or buildings. It exhibits an elongation at break >300%, tensile strength >31 MPa, yellowing index change (ΔY1) <2.0, tensile strength retention >80%, and mass loss <1.0%, demonstrating excellent low-temperature performance, UV resistance, and long-term stability. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0024] Polytetrahydrofuran (PTMG, Mn=2000) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (P117874), and polycarbonate diol (PTMG, Mn=2000) was purchased from Ron Reagent (R138735).

[0025] Preparation Example 1 Preparation of fluorinated high isocyanates: a1: Under nitrogen protection, 100 parts by weight of toluene diisocyanate and 20 parts by weight of isomeric xylene were added to a dry reactor. The mixture was stirred continuously and nitrogen was introduced. The reactor was heated to 75°C. 5.2 parts by weight of trimethylolpropane and 20 parts by weight of ethyl acetate were mixed evenly and then added dropwise to the reactor at a constant rate. The addition time was 180 min, the reaction time was 3.5 h, and the reaction temperature was 80°C to obtain the first prepolymer. a2: The first prepolymer obtained in step a1 is subjected to a two-stage thin-film evaporator to remove excess free toluene diisocyanate monomer until the free toluene diisocyanate in the first prepolymer is less than 0.5 wt% of the total amount of materials in the reaction system. Under nitrogen protection, 4.1 parts by weight of 2,2,3,3,4,4-hexafluoro-1,5-pentanediol is added dropwise over 40 min, for a reaction time of 2.5 h at a reaction temperature of 80 °C. Then, the temperature is lowered to below 50 °C and dried to obtain fluorinated high isocyanate.

[0026] Preparation Example 2 Preparation of perfluorodecylethyl methacrylate / trifluoroethyl methacrylate / trimethoxysilane methacrylate (PFEMA / TFEMA / MSMA) copolymer: b1: Add 9 parts by weight of PFEMA, 9 parts by weight of TFEMA, 12 parts by weight of MSMA and 70 parts by weight of anhydrous ethanol to a reaction flask, stir at room temperature for 10 min until homogeneous, purge with nitrogen for 20 min to remove oxygen, add 0.3 parts by weight of the initiator azobisisobutyronitrile, continue nitrogen protection, heat to 70℃, keep at a constant temperature for 8 h, cool to room temperature to obtain the reaction solution; b2: Slowly drop the reaction solution obtained in step b1 into 5 times the volume of cold n-hexane, allow to fully precipitate, filter, and dry the resulting white flocculent copolymer under vacuum at 50℃ for 12 h to obtain the PFEMA / TFEMA / MSMA copolymer.

[0027] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 2 is that the total mass of PFEMA and TFEMA remains unchanged, and the mass ratio of PFEMA to TFEMA is 2:1.

[0028] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 2 is that the total mass of PFEMA and TFEMA remains unchanged, and the mass ratio of PFEMA to TFEMA is 1:2.

[0029] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 2 is that the total mass of PFEMA, TFEMA and MSMA remains unchanged, and the mass ratio of PFEMA, TFEMA and MSMA is 1:1:2.

[0030] Specifically, the preparation of step b1 is different, as follows: 7.5 parts by weight of PFEMA, 7.5 parts by weight of TFEMA, 15 parts by weight of MSMA and 70 parts by weight of anhydrous ethanol are added to a reaction flask, stirred at room temperature for 10 min until homogeneous, and then purged with nitrogen for 20 min to remove oxygen. Then, 0.3 parts by weight of the initiator azobisisobutyronitrile are added, and nitrogen protection is continued. The temperature is raised to 70°C and the reaction is kept constant for 8 h. After cooling to room temperature, the reaction solution is obtained.

[0031] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 2 is that the total mass of PFEMA, TFEMA and MSMA remains unchanged, and the mass ratio of PFEMA, TFEMA and MSMA is 3.5:3.5:3.

[0032] Specifically, the preparation of step b1 is different, as follows: 10.5 parts by weight of PFEMA, 10.5 parts by weight of TFEMA, 9 parts by weight of MSMA and 70 parts by weight of anhydrous ethanol are added to a reaction flask, stirred at room temperature for 10 min until homogeneous, and then purged with nitrogen for 20 min to remove oxygen. Then, 0.3 parts by weight of the initiator azobisisobutyronitrile are added, and nitrogen protection is continued. The temperature is raised to 70°C and the reaction is kept constant for 8 h. After cooling to room temperature, the reaction solution is obtained.

[0033] Comparative Preparation Example 1 The difference between Preparation Example 1 and Preparation Example 2 is that TFEMA and other materials were replaced with PFEMA.

[0034] Specifically, the preparation of step b1 is different, as follows: 18 parts by weight of PFEMA, 12 parts by weight of MSMA and 70 parts by weight of anhydrous ethanol are added to a reaction flask, stirred at room temperature for 10 min until homogeneous, and after purging with nitrogen for 20 min to remove oxygen, 0.3 parts by weight of the initiator azobisisobutyronitrile are added, nitrogen protection is continued, the temperature is raised to 70°C, and the reaction is kept at a constant temperature for 8 h. After cooling to room temperature, the reaction solution is obtained. Accordingly, step b2 yields the PFEMA / MSMA copolymer.

[0035] Comparative Preparation Example 2 The difference between Preparation Example 2 and Preparation Example 2 is that PFEMA and other materials were replaced with TFEMA.

[0036] Specifically, the preparation of step b1 is different, as follows: 18 parts by weight of TFEMA, 12 parts by weight of MSMA and 70 parts by weight of anhydrous ethanol are added to a reaction flask, stirred at room temperature for 10 min until homogeneous, and after purging with nitrogen for 20 min to remove oxygen, 0.3 parts by weight of the initiator azobisisobutyronitrile are added, nitrogen protection is continued, the temperature is raised to 70°C, and the reaction is kept at a constant temperature for 8 h. After cooling to room temperature, the reaction solution is obtained. Accordingly, step b2 yields the TFEMA / MSMA copolymer.

[0037] Comparative preparation example 3 Preparation of fluorinated diisocyanates with side chains: Six parts by weight of trimethylolpropane were stirred and dehydrated at 110°C and a vacuum of 750 mm Hg for 0.5 h. Under nitrogen protection, 100 parts by weight of isophorone diisocyanate and 0.03 parts by weight of stannous octoate were added, and the reaction was carried out at 80°C for 2 h. Then, 5 parts by weight of 2,2,2-trifluoroethanol and 0.03 parts by weight of stannous octoate were added, and the reaction was carried out at 80°C for another 3 h to obtain a diisocyanate with fluorinated side chains.

[0038] Comparative preparation example 4 The difference between Preparation Example 4 and Preparation Example 2 is that PFEMA was replaced by hexafluorobutyl methacrylate (HFBMA) by mass.

[0039] Specifically, the preparation of step b1 is different, as follows: 9 parts by weight of HFBMA, 9 parts by weight of TFEMA, 12 parts by weight of MSMA and 70 parts by weight of anhydrous ethanol are added to a reaction flask, stirred at room temperature for 10 min until homogeneous, and then purged with nitrogen for 20 min to remove oxygen. 0.3 parts by weight of the initiator azobisisobutyronitrile are added, and nitrogen protection is continued. The temperature is raised to 70°C and the reaction is kept constant for 8 h. The mixture is then cooled to room temperature to obtain the reaction solution. Accordingly, step b2 yields the HFBMA / TFEMA / MSMA copolymer.

[0040] Example 1 Example 1 provides a fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material, comprising the following raw materials in parts by weight: 50 parts of soft segment component, 30 parts of hard segment component, 15 parts of functionalized side chain component, 3 parts of crosslinking agent, and 0.08 parts of catalyst; wherein, the soft segment component is polytetrahydrofuran (PTMG, Mn=2000); the hard segment component consists of 20 parts of fluorinated high isocyanate prepared by the preparation method of Example 1 and 10 parts of silicon-containing segment, the silicon-containing segment being KH-560; the functionalized side chain component is PFEMA / TFEMA / MSMA copolymer prepared by the preparation method of Example 2; the crosslinking agent is ethylene glycol diglycidyl ether (EGDE); and the catalyst is dibutyltin dilaurate.

[0041] The mass ratio of fluorinated isocyanate to KH-560 is 2:1; the mass ratio of soft segment component to hard segment component is 5:3.

[0042] Preparation method: S1: Preparation of prepolymer: Under dry N2 gas protection, the soft segment component is vacuum dehydrated at 110°C for 1.5 hours, cooled to 80°C, and the fluorinated high isocyanate and catalyst are added. The reaction is carried out under N2 protection for 2.5 hours to obtain the prepolymer; S2: Hard segment chain extension and side branching: The temperature of the prepolymer obtained in step S1 is lowered to 60°C, and silicon-containing segments and functionalized side chain components are added sequentially. The reaction is stirred continuously for 1.5 hours to obtain a mixture; S3: Crosslinking and curing: Add crosslinking agent to the mixture obtained in step S2, stir evenly and pour into a mold, first cure at 90°C for 3 hours, then cure at 110°C for 5 hours; to obtain fluorosilicone modified polyurethane-based low-temperature UV resistant composite material.

[0043] Example 2 Example 2 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material. The difference from Example 1 is that the total mass of fluorinated high isocyanate and KH-560 remains unchanged, and the mass ratio of fluorinated high isocyanate and KH-560 is 3:2.

[0044] The preparation method is the same as in Example 1.

[0045] Example 3 Example 3 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material. The difference from Example 1 is that the total mass of fluorinated high isocyanate and KH-560 remains unchanged, and the mass ratio of fluorinated high isocyanate to KH-560 is 11:4.

[0046] The preparation method is the same as in Example 1.

[0047] Example 4 Example 4 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the functionalized side chain components are replaced by an equal mass of the PFEMA / TFEMA / MSMA copolymer prepared by the method of Preparation Example 3.

[0048] The preparation method is the same as in Example 1.

[0049] Example 5 Example 5 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the functionalized side chain components are replaced by an equal mass of the PFEMA / TFEMA / MSMA copolymer prepared by the method of Preparation Example 4.

[0050] The preparation method is the same as in Example 1.

[0051] Example 6 Example 6 provides a fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the functionalized side chain components are replaced by an equal mass of the PFEMA / TFEMA / MSMA copolymer prepared by the method of Preparation Example 5.

[0052] The preparation method is the same as in Example 1.

[0053] Example 7 Example 7 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the functionalized side chain components are replaced by an equal mass of the PFEMA / TFEMA / MSMA copolymer prepared by the method of Preparation Example 6.

[0054] The preparation method is the same as in Example 1.

[0055] Example 8 Example 8 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the total mass of the soft segment component and the hard segment component remains unchanged, and the mass ratio of the soft segment component to the hard segment component is 7:3.

[0056] Specifically, the raw material composition of the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material is different. This embodiment contains the following raw materials in parts by weight: 56 parts of soft segment component, 24 parts of hard segment component, 15 parts of functionalized side chain component, 3 parts of crosslinking agent, and 0.08 parts of catalyst; wherein, the soft segment component is polytetrahydrofuran (PTMG, Mn=2000); the hard segment component consists of 16 parts of fluorinated high isocyanate prepared by the preparation method of Preparation Example 1 and 8 parts of silicon-containing segment, the silicon-containing segment being KH-560; the functionalized side chain component is PFEMA / MSMA copolymer prepared by the preparation method of Preparation Example 2; the crosslinking agent is ethylene glycol diglycidyl ether (EGDE); and the catalyst is dibutyltin dilaurate.

[0057] The preparation method is the same as in Example 1.

[0058] Example 9 Example 9 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the total mass of the soft segment component and the hard segment component remains unchanged, and the mass ratio of the soft segment component to the hard segment component is 11:9.

[0059] Specifically, the raw material composition of the fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material is different. This embodiment contains the following raw materials in parts by weight: 44 parts of soft segment component, 36 parts of hard segment component, 15 parts of functionalized side chain component, 3 parts of crosslinking agent, and 0.08 parts of catalyst; wherein, the soft segment component is polytetrahydrofuran (PTMG, Mn=2000); the hard segment component consists of 24 parts of fluorinated high isocyanate prepared by the preparation method of Preparation Example 1 and 12 parts of silicon-containing segment, the silicon-containing segment being KH-560; the functionalized side chain component is PFEMA / MSMA copolymer prepared by the preparation method of Preparation Example 2; the crosslinking agent is ethylene glycol diglycidyl ether (EGDE); and the catalyst is dibutyltin dilaurate.

[0060] The preparation method is the same as in Example 1.

[0061] Comparative Example 1 Comparative Example 1 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that it does not contain KH-560.

[0062] The preparation method is the same as in Example 1.

[0063] Comparative Example 2 Comparative Example 2 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the functionalized side chain components are replaced by an equal mass of PFEMA / MSMA copolymer prepared by the method of Comparative Preparation Example 1.

[0064] The preparation method is the same as in Example 1.

[0065] Comparative Example 3 Comparative Example 3 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the functionalized side chain components are replaced by an equal mass of TFEMA / MSMA copolymer prepared by the method of Comparative Preparation Example 2.

[0066] The preparation method is the same as in Example 1.

[0067] Comparative Example 4 Comparative Example 4 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the fluorine-containing high isocyanate is replaced by an equal mass of a side-chain fluorine-containing diisocyanate prepared by the method of Comparative Preparation Example 3.

[0068] The preparation method is the same as in Example 1.

[0069] Comparative Example 5 Comparative Example 5 provides a fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material, which differs from Example 1 in that the functionalized side panel component is replaced by an equal mass of the HFBMA / TFEMA / MSMA copolymer prepared by the method of Comparative Preparation Example 4.

[0070] The preparation method is the same as in Example 1.

[0071] Performance testing The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite materials prepared in Examples 1-9 and Comparative Examples 1-5 were subjected to performance tests. The elongation at break was tested according to GB / T528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". Before testing, the fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite materials prepared in Examples 1-9 and Comparative Examples 1-5 were conditioned in an environmental chamber at -40℃ for ≥3 hours to ensure uniform internal and external temperatures and reach thermal equilibrium before immediate testing. Aging resistance testing was conducted according to ASTM G154-16, using a UVA-340 lamp with a power of 0.89 W / (m²). 2 UV accelerated aging tests were conducted at 340nm (mm), with 8h illumination (70℃) / 4h condensation (50℃) cycles for a total duration of 1000h. The yellowing index change ΔY1 was calculated using ASTM E313-20 standards. Tensile strength before and after aging, as well as the tensile strength retention rate and mass loss rate of the aged samples, were also tested. Tensile strength was tested according to GB / T528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The results are shown in Table 1. The formula for calculating the tensile strength retention rate is: Tensile strength retention rate (%) = σ1 / σ0 × 100%. In the formula, σ0 represents the tensile strength before aging, and σ1 represents the tensile strength after aging. The formula for calculating the mass loss rate is: Mass loss rate (%) = (m0 - m1) / m0 × 100%. In the formula, m0 represents the mass before aging, and m1 represents the mass after aging.

[0072] Table 1 Results and Analysis Based on Examples 1, 2-3, and Table 1, it can be seen that adjusting the mass ratio of fluorinated isocyanate to KH-560 in the hard segment component can affect the low-temperature performance, UV resistance, and long-term stability of the fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material. In Example 1, when the mass ratio of isocyanate to KH-560 is 2:1, the composite material exhibits the best low-temperature performance, UV resistance, and long-term stability.

[0073] Based on Examples 1, 4-5, and Table 1, it can be seen that adjusting the content of PFEMA and TFEMA in the functionalized side-chain PFEMA / TFEMA / MSMA copolymer can affect the low-temperature performance, UV resistance, and long-term stability of the fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material. In Example 4, the TFEMA content of the functionalized side-chain copolymer was reduced, and in Example 6, the PFEMA content in the functionalized side-chain copolymer was relatively low. Both resulted in the low-temperature performance, UV resistance, and long-term stability of the fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material being worse than those in Example 1.

[0074] Based on Examples 1, 6-7, and Table 1, it can be seen that the content of fluorinated acrylate monomers in Example 6 is relatively low, and the low-temperature performance of the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material is significantly lower than that in Example 1. At the same time, its UV resistance and long-term stability are also lower than those in Example 1. In Example 7, the content of silicone acrylate monomers is relatively low, and the UV resistance, long-term stability, and low-temperature performance of the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material are all lower than those in Example 1.

[0075] Based on Examples 1, 8-9 and Table 1, it can be seen that the hard segment component in Example 8 is less and the hydrogen bond density is lower, while the hard segment component in Example 9 is more and the microphase separation is excessive. Both of these results in the low-temperature performance, UV resistance and long-term stability of the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material being worse than those in Example 1.

[0076] As can be seen from Example 1, Comparative Example 1 and Table 1, when KH-560 is not added to the hard segment component of Comparative Example 1, there is no Si-O-Si crosslinking network due to the lack of silicon, which leads to a significant reduction in the low-temperature performance, UV resistance and long-term stability of the composite material.

[0077] As can be seen from Example 1, Comparative Examples 2-3 and Table 1, replacing PFEMA and TFEMA in the functionalized side chain copolymer with each other by equal mass disrupts the synergistic effect of the rigidity of long-chain fluorine and the flexibility of short-chain fluorine, thereby significantly reducing the low-temperature performance, UV resistance and long-term stability of the composite material.

[0078] Based on Example 1, Comparative Example 4, and Table 1, it can be seen that in Comparative Example 4, replacing the fluorinated high isocyanate with a side-chain fluorinated diisocyanate by the same mass resulted in inferior low-temperature performance, UV resistance, and long-term stability compared to Example 1. This may be because the fluorinated high isocyanate molecule has three -NCO atoms at its end, resulting in a high crosslinking density. It works in conjunction with the silicon-oxygen bonds of KH-560 to anchor the hard segments, while the side-chain fluorinated diisocyanate is only a linear low-fluorine additive with insufficient crosslinking points and fluorine enrichment, leading to inferior performance.

[0079] As can be seen from Example 1, Comparative Example 5 and Table 1, replacing PFEMA with hexafluorobutyl methacrylate (HFBMA) by the same mass resulted in a significant decrease in low-temperature performance, UV resistance and long-term stability. This may be because PFEMA has better durability than HFBMA, and PFEMA and TFEMA have better rigid-flexible complementarity, lower surface energy, denser cross-linking and stronger durability.

[0080] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the products, methods and principles of this application should be covered within the scope of protection of this application.

Claims

1. A fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material, characterized in that, The raw materials contain the following parts by weight: 40-60 parts of soft segment component, 20-40 parts of hard segment component, 10-20 parts of functionalized side chain component, 1-5 parts of crosslinking agent, and 0.05-0.1 parts of catalyst; The hard segment component comprises 15-25 parts of fluorinated high isocyanate and 5-15 parts of silicon-containing segments; The raw materials for the functionalized side chain include 15-21 parts of fluorinated acrylate monomers and 9-15 parts of silicone acrylate monomers. The silicon-containing segment is selected from at least one of KH-560 and KH-550; The fluorinated acrylate monomer is selected from at least one of perfluorodecylethyl methacrylate, trifluoroethyl methacrylate, and hexafluorobutyl methacrylate, and the silicone acrylate monomer is selected from at least one of trimethoxysilane methacrylate and KH-570.

2. The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 1, characterized in that, The mass ratio of the fluorinated high isocyanate to the silicon-containing segment is (1.5-2.75):

1.

3. The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 1, characterized in that, The preparation of the fluorinated high isocyanate includes the following steps: a1: Under inert gas protection, toluene diisocyanate and isomeric xylene are added, stirred, and heated to 70-80℃; trimethylolpropane and ethyl acetate are added, mixed, and reacted for 3-4 hours at a reaction temperature of 70-90℃ to obtain the first prepolymer; a2: Under inert gas protection, 2,2,3,3,4,4-hexafluoro-1,5-pentanediol is added to the first prepolymer prepared in step a1, and the reaction is carried out for 2-3 hours at a temperature of 70-90℃. After cooling and drying, the fluorinated high isocyanate is obtained.

4. The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 1, characterized in that, The mass ratio of the fluorinated acrylate monomer to the silicone acrylate monomer is (1-2.33):

1.

5. The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 1, characterized in that, The fluorinated acrylate monomers include perfluorodecyl ethyl methacrylate and trifluoroethyl methacrylate; the mass ratio of perfluorodecyl ethyl methacrylate to trifluoroethyl methacrylate is (0.5-2):

1.

6. The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 5, characterized in that, The preparation of the functionalized side chain includes the following steps: b1: Perfluorodecyl ethyl methacrylate, trifluoroethyl methacrylate, trimethoxysilane methacrylate and ethanol are added to a reaction flask, stirred to remove oxygen, azobisisobutyronitrile initiator is added, the temperature is raised to 60-80℃, the reaction is kept at a constant temperature for 7-9 hours, and then cooled to obtain the reaction solution. b2: Add the reaction solution obtained in step b1 to cold n-hexane, precipitate, filter, and dry to obtain the functionalized side chain.

7. The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 1, characterized in that, The mass ratio of the soft segment component to the hard segment component is (1.22-2.33):

1.

8. The fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 1, characterized in that, The crosslinking agent is ethylene glycol diglycidyl ether; the catalyst is dibutyltin dilaurate.

9. A method for preparing the fluorosilicone-modified polyurethane-based low-temperature UV-resistant composite material according to claim 1, characterized in that, Includes the following steps: S1: Preparation of prepolymer: Under inert gas protection, the soft segment component is vacuum dehydrated at 100-120℃ for 1-2 hours, cooled to 70-90℃, the fluorinated high isocyanate and catalyst are added, and the reaction is carried out under inert gas protection for 2-3 hours to obtain the prepolymer; S2: Hard segment chain extension and side chain branching: The temperature of the prepolymer obtained in step S1 is reduced to 50-70℃, the silicon-containing segments and the functionalized side chain components are added, and the mixture is stirred for 1-2 hours to obtain a mixture. S3: Crosslinking and curing: Add the crosslinking agent to the mixture obtained in step S2, stir evenly, pour into a mold, cure at 80-100℃ for 2-4 hours, and then cure at 100-120℃ for 4-6 hours; to obtain the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material.

10. The application of the fluorosilicone modified polyurethane-based low-temperature UV-resistant composite material according to claims 1-8 in the preparation of waterproof materials for cold-weather outdoor equipment or buildings.

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