Sealing material for doors and windows and preparation method thereof

Abstract

The invention discloses a sealing material for doors and windows, and relates to the technical field of sealing materials, the sealing material is composed of a biomass polyester elastomer, three-stage core-shell state nanometer SiO2, vulcanized rubber, a plasticizer, a dispersant and a functional auxiliary agent; wherein the three-stage shell-core state nano SiO2 comprises a mesoporous nano SiO2 core, perfluoropolyether silane, an interwoven network layer formed by C = N bonds and C18-QAS, the interwoven network layer and the C18-QAS are sequentially coated outside the mesoporous nano SiO2 core, and a fluorine chain layer formed by the perfluoropolyether silane not only has a hydrophobic effect, but also can form space matching with the interwoven network layer formed by the C = N bonds, so that stress concentration is avoided; meanwhile, the C = N bond is reversibly fractured or recombined under stress, so that energy between the nano-particles and the cross section of the matrix is dissipated, and the fracture performance is improved; the quaternary ammonium salt cations of C18-QAS and carboxyl contained in the middle shell generate electrostatic attraction, so that the polymerization direction of the outer shell is perpendicular to the surface of the inner core, a nanoscale groove structure is formed, and cross-interface permeation of water molecules is efficiently inhibited.

Description

Technical Field

[0001] The invention relates to the technical field of sealing materials, and in particular to a sealing material for doors and windows and a preparation method thereof. Background Art

[0002] With the continuous improvement of building energy conservation and green environmental protection requirements, the performance optimization of door and window sealing materials, as key components that affect the air tightness, thermal insulation and durability of buildings, has attracted much attention. Traditional sealing materials mostly rely on petroleum-based elastomers (such as EPDM rubber, silicone rubber) and mineral filler systems. Although they have a certain sealing effect, they have significant defects in extreme environmental adaptability, long-term aging resistance and environmental friendliness.

[0003] At the same time, in the prior art, in order to improve the hydrophobicity, nano-silica surface is generally modified by grafting fluorosilane or adding fluorine-containing polymers. Although this can improve the waterproof performance of the sealing material to a certain extent, the fluorination modification can easily lead to a decrease in the compatibility of the filler-matrix interface, induce stress concentration, and cause the material to crack under low temperature or high pressure. In addition, the conventional modification process causes the fluorine chain to decompose due to high temperature, and the actual hydrophobic effect is limited, which greatly reduces the waterproof effect of the sealing material. Summary of the invention

[0004] The purpose of the present invention is to provide a sealing material for doors and windows and a preparation method thereof, so as to solve the following technical problems:

[0005] How to simultaneously improve the hydrophobicity and weather resistance of door and window sealing materials.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] In a first aspect, the present invention discloses a sealing material for doors and windows, which is composed of the following components in parts by weight:

[0008] 30-40 parts of biomass polyester elastomer;

[0009] Tertiary core-shell nano-SiO2 12-20 parts;

[0010] Vulcanized rubber 20-30 parts;

[0011] 5-10 parts of plasticizer;

[0012] 1-3 parts of dispersant;

[0013] 2-5 parts of functional additives.

[0014] Preferably, the sealing material for doors and windows is composed of the following components in parts by weight:

[0015] 35 parts of biomass polyester elastomer;

[0016] 16 parts of three-level core-shell nano-SiO2;

[0017] 25 parts of vulcanized rubber;

[0018] 8 parts of plasticizer;

[0019] 2 parts of dispersant;

[0020] 3 parts of functional additives.

[0021] Furthermore, the three-level core-shell nano-SiO2 includes an inner core and an inner shell, an intermediate layer and an outer shell which are sequentially coated on the outside of the inner core. The inner core is mesoporous nano-SiO2, the inner shell is perfluoropolyether silane, the intermediate layer is an interwoven network layer formed by C=N bonds, and the outer shell is octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride.

[0022] Furthermore, the preparation method of the biomass polyester elastomer comprises the following steps:

[0023] Step A1, mixing castor oil polyol and bio-based furandicarboxylic acid (FDCA) in a weight ratio of 1: (0.5-0.8) (preferably 1: 0.65), and performing a pre-polycondensation reaction at 160-180° C. (preferably 170° C.) for 2 h under nitrogen (N2) protection;

[0024] Step A2, then adding tetraisopropyl titanate (TPT) as a catalyst, raising the temperature to 200-220° C. (preferably 210° C.), and carrying out polycondensation reaction under a vacuum degree of 1000 Pa until the viscosity of the reactant reaches 500 Pa.s; the initial high vacuum degree is conducive to promoting the removal of small molecules and forming linear segment chains;

[0025] Step A3, adding pentaerythritol triacrylate (PET3A) as a regulating agent to the reaction system in portions and continuing the reaction for 4 hours, and reducing the vacuum degree from 1000 Pa to 50 Pa in portions during the reaction;

[0026] Step A4, cooling the product to 180°C, then adding 1-2wt% of dodecyl epoxysiloxane (DEDS) to the total amount of castor oil polyol and FDCA to react for 20 minutes, and realizing chain end functionalization through addition reaction of epoxy groups with residual hydroxyl groups to finally obtain biomass polyester elastomer.

[0027] Furthermore, in step A2, the amount of tetraisopropyl titanate used is 0.02-0.05 wt %, preferably 0.03 wt %, of the total amount of castor oil polyol and bio-based furandicarboxylic acid.

[0028] Further, in step A3, the total amount of pentaerythritol triacrylate is 0.02-0.05wt% (preferably 0.03wt%) of the total amount of castor oil polyol and bio-based furandicarboxylic acid, and the pentaerythritol triacrylate is added three times, each addition amount is the same, the time interval between two adjacent additions is 30 minutes, and the corresponding vacuum degrees of the three additions are 1000Pa, 200Pa, and 50Pa, respectively.

[0029] Based on this, a preferred method for preparing a biomass polyester elastomer is obtained, comprising the following steps:

[0030] Step a1, mixing castor oil polyol and FDCA in a weight ratio of 1:0.65, and performing a pre-polycondensation reaction at 170° C. for 2 h under N2 protection;

[0031] Step a2, then adding 0.03wt% of TPT as a catalyst accounting for the total amount of castor oil polyol and FDCA, raising the temperature to 210°C, and carrying out polycondensation reaction under a vacuum degree of 1000Pa until the viscosity of the reactant reaches 500Pa.s;

[0032] Step a3, adding PET3A as a regulating agent to the reaction system, adding PET3A again after reacting for 30 minutes, and reducing the vacuum degree to 200Pa, continuing the reaction for 30 minutes, adding PET3A again, and reducing the vacuum degree to 50Pa, and continuing the reaction for 3 hours; the total amount of PET3A added accounts for 0.03wt% of the total amount of castor oil polyol and FDCA;

[0033] Step a4, cooling the product to 180° C., then adding DEDS accounting for 1.5 wt % of the total amount of castor oil polyol and FDCA and reacting for 20 min to finally obtain a biomass polyester elastomer.

[0034] Furthermore, the preparation method of the three-level core-shell nano-SiO2 comprises the following steps:

[0035] Step B1, perfluoropolyether thiol (PFPE-SH) and mesoporous nano-SiO2 are dispersed in tetrahydrofuran (THF) at a ratio of 2.5 mL: 1 g, and the ratio of THF to mesoporous nano-SiO2 is 20 mL: 1 g; then a photoinitiator is added, and 365 nm ultraviolet light is irradiated for 30 min under N2 protection while accompanied by ultrasonic stirring, and FS iO2 is obtained after filtering and washing;

[0036] Step B2, γ-aminopropyltriethoxysilane (KH-550) and glycidyl methacrylate (GMA) were mixed in a molar ratio of 1:2, and hydrolyzed at 60°C for 2h, and then FS i O2 was immersed in the hydrolyzate and stirred for 10min, then taken out, and thermally cured at 120°C to form C=NFS i O2;

[0037] Step B3, octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride (C18-QAS), azobisisobutyronitrile (AI BN) and C=NFS i O2 are dissolved in toluene at a weight ratio of 100:1:25, and the amount ratio of toluene to C=NFS i O2 is 20mL:1g; then, polymerization reaction is carried out at 70°C for 6h, and QAS-C=NFS i O2 is obtained after washing and drying, i.e., three-level core-shell nano-Si O2.

[0038] Furthermore, in step A1, the pore size of the mesoporous nano-silica is 2-5 nm, the wall thickness is 10-15 nm, and the BET specific surface area is 400-500 m 2 / g;

[0039] Preferably, the photoinitiator is benzophenone (BP).

[0040] Furthermore, the preparation method of the vulcanized rubber is: mixing nitrile rubber and isocyanate-terminated polyurethane prepolymer in a weight ratio of 3:1, and performing reaction extrusion at 180-200° C. in a twin-screw extruder, with the shear rate controlled at 500-800 s -1 , vulcanization time 30-90 seconds.

[0041] Furthermore, the plasticizer is a mixture of epoxidized soybean oil and citrate in a weight ratio of 1:1.

[0042] Furthermore, the dispersant is a mixture of lecithin and hydroxylated cellulose nanocrystals in a weight ratio of 2:1.

[0043] Furthermore, the functional additive is a mixture of benzotriazole, hindered amine and graphene quantum dots in a ratio of 1:1:1.

[0044] In a second aspect, the present invention further discloses a method for preparing the sealing material for doors and windows as described above, comprising the following steps:

[0045] Step 1: Add the biomass polyester elastomer and the vulcanized rubber into an internal mixer in proportion, and mix them at 160° C. for 5 minutes to obtain a premix;

[0046] Step 2, after the temperature of the premix is ​​raised to 175°C, the three-level core-shell nano-SiO2 is added to the premix in small amounts and multiple times, each time with an interval of 5 minutes, and mixing for 10 minutes after the last addition to obtain a slurry;

[0047] Step 3: Add plasticizer, dispersant and functional additive to the slurry and continue to mix for 10-20 minutes, then transfer to a two-stage extruder, first melt blend at 180-200°C for 20 minutes, then melt blend at 150-160°C for 30 minutes to obtain a sealing material;

[0048] Step 4: The sealing material is molded and discharged through a micro-foaming mold at a foaming rate of 5-8% to obtain a sealing material for doors and windows.

[0049] Beneficial effects of the present invention:

[0050] 1. The sealing material for doors and windows of the present invention introduces three-level core-shell nano-SiO2 as the main hydrophobic performance improvement component. Among the three-level core-shell nano-SiO2, mesoporous nano-SiO2 iO2 is used as the core. When the sealing material is squeezed, it can absorb stress through mesopore collapse to improve impact toughness. The outer inner shell is a fluorine chain layer formed by perfluoropolyether silane, which not only has a hydrophobic effect, but also can form a spatial match with the interwoven network layer formed by the C=N bonds of the intermediate shell to avoid stress concentration. At the same time, the C=N bonds can be reversibly broken or reorganized under stress, further dissipating the energy between the nanoparticles and the matrix cross section, greatly improving its fracture performance. The quaternary ammonium salt cations of C18-QAS in the outer shell generate electrostatic attraction with the carboxyl groups contained in the intermediate shell, so that the polymerization direction of the outer shell is perpendicular to the core surface, forming a nanoscale groove structure. This multi-scale rough surface can achieve superhydrophobic performance and form a hydrophobic gradient with the inner shell, so it can effectively inhibit the cross-interface penetration of water molecules. Therefore, the three-level shell core-state nano-SiO2, as a hydrophobic performance improvement component, can improve the hydrophobic performance while ensuring the mechanical properties.

[0051] 2. The sealing material for doors and windows of the present invention uses bio-based polyester fiber as the main raw material, which is combined with vulcanized rubber to introduce reversible hydrogen bonds and covalent cross-linking bonds into the molecular chain, which is beneficial to improving the change rate of its elastic modulus; at the same time, the siloxane-terminated elastomer molecular chain in the bio-based polyester fiber can be chemically coupled with the tertiary core-shell nano-SiO2 through the Si-OSi bond, so that the interface peeling strength is improved, thereby improving the fracture performance of the sealing material, and the use of bio-based raw materials is environmentally friendly and meets the needs of modern green development. DETAILED DESCRIPTION

[0052] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0054] Preparation Example 1

[0055] Preparation of biomass polyester elastomer:

[0056] 100g of castor oil polyol was mixed with 65g of FDCA, and reacted at 170°C for 2h under N2 protection; then 4.95g of TPT was added, the temperature was raised to 210°C, and the reaction was carried out under a vacuum degree of 1000Pa, and the viscosity of the reactant was monitored by an online torque sensor until it reached 500Pa.s; 1.65g of PET3A was added to the reaction system, and 1.65g of PET3A was added again after reacting for 30min, and the vacuum degree was reduced to 200Pa, and the reaction was continued for 30min, and 1.65g of PET3A was added again, and the vacuum degree was reduced to 50Pa, and the reaction was continued for 3h; the product was cooled to 180°C, and then 2.475g of DEDS was added to react for 20min to finally obtain a biomass polyester elastomer.

[0057] Preparation Example 2

[0058] Preparation of three-level core-shell nano-SiO2:

[0059] 75 mL of PFPE-SH and 30 g of mesoporous nano-SiO2 were dispersed in 60 mL of THF, and then 0.5 g of BP was added. The mixture was irradiated with 365 nm ultraviolet light for 30 min under N2 protection and accompanied by ultrasonic stirring. After filtration and washing with deionized water, FSiO2 was obtained. KH-550 and GMA were mixed in a molar ratio of 1:2, hydrolyzed at 60°C for 2 h, and then FSiO2 was immersed in the hydrolyzate and stirred for 10 min, taken out, and thermally cured at 120°C to form C=NFSiO2, which weighed 43 g. 172 g of C18-QAS, 1.72 g of AI BN and 43 g of C=NFSiO2 were dissolved in 860 mL of toluene, and then polymerized at 70°C for 6 h. After washing with deionized water and drying, QAS-C=NFSiO2, i.e., three-level core-shell nano-SiO2, was obtained.

[0060] Preparation Example 3

[0061] Preparation of vulcanized rubber:

[0062] The nitrile rubber and the isocyanate-terminated polyurethane prepolymer were mixed in a weight ratio of 3:1 and subjected to reactive extrusion in a twin-screw extruder at 190 °C with a shear rate of 650 s -1 , vulcanization time is 60 seconds, and finally vulcanized rubber is obtained.

[0063] Comparative Preparation Example 1

[0064] Preparation of three-level core-shell nano-SiO2:

[0065] 75 mL of PFPE-SH and 30 g of mesoporous nano-SiO2 were dispersed in 60 mL of THF, and then 0.5 g of BP was added. Under the protection of N2, the mixture was irradiated with 365 nm ultraviolet light for 30 min accompanied by ultrasonic stirring. After filtration and washing with deionized water, 34 g of FSiO2 was obtained. 136 g of C18-QAS, 1.36 g of AI BN and 34 g of FSiO2 were dissolved in 860 mL of toluene, and then polymerized at 70 ° C for 6 h. After washing with deionized water and drying, QAS--FSiO2, i.e., three-level core-shell nano-SiO2, was obtained.

[0066] Example 1

[0067] Preparation of sealing materials for doors and windows:

[0068] 35g of the biomass polyester elastomer prepared in Preparation Example 1 and 25g of the vulcanized rubber prepared in Preparation Example 3 were added to a laboratory internal mixer and mixed at 160°C for 5 min. The temperature was then raised to 175°C. The three-stage core-shell nano-Si prepared in Preparation Example 2 was added to the internal mixer in three portions. O2, add 5g for the first time, 5g for the second time, and 6g for the third time, with an interval of 5min each time, and mix for 10min after the last addition to obtain a slurry; add 8g of plasticizer (a mixture of epoxidized soybean oil and citrate in a weight ratio of 1:1), 2g of dispersant (a mixture of lecithin and hydroxylated cellulose nanocrystals in a weight ratio of 2:1) and 3g of functional additive (a mixture of benzotriazole, hindered amine and graphene quantum dots in a ratio of 1:1:1) to the slurry, continue mixing for 15min, and then transfer to a two-stage extruder, first melt blend at 190°C for 20min, and then melt blend at 155°C for 30min to obtain a sealing material; the sealing material is molded and discharged through a micro-foaming mold with a foaming rate of 6% to obtain a sealing material for doors and windows.

[0069] Example 2

[0070] 30g of the biomass polyester elastomer prepared in Preparation Example 1 and 20g of the vulcanized rubber prepared in Preparation Example 3 were added to a laboratory internal mixer and mixed at 160°C for 5min. The temperature was then raised to 175°C. The three-stage core-shell nano-Si prepared in Preparation Example 2 was added to the internal mixer in three portions. O2, adding 4g each time, each time with an interval of 5min, and mixing for 10min after the last addition to obtain a slurry; adding 5g of plasticizer (a mixture of epoxidized soybean oil and citrate in a weight ratio of 1:1), 1g of dispersant (a mixture of lecithin and hydroxylated cellulose nanocrystals in a weight ratio of 2:1) and 2g of functional additive (a mixture of benzotriazole, hindered amine and graphene quantum dots in a ratio of 1:1:1) to the slurry, and continuing to mix for 10min, and then transferring to a two-stage extruder, first melt blending at 180°C for 20min, and then melt blending at 150°C for 30min to obtain a sealing material; the sealing material is molded and discharged through a micro-foaming mold with a foaming rate of 6% to obtain a sealing material for doors and windows.

[0071] Example 3

[0072] 40g of the biomass polyester elastomer prepared in Preparation Example 1 and 30g of the vulcanized rubber prepared in Preparation Example 3 were added to a laboratory internal mixer and mixed at 160°C for 5min. The temperature was then raised to 175°C. The three-stage core-shell nano-Si prepared in Preparation Example 2 was added to the internal mixer in three portions. O2, add 6g for the first time, 6g for the second time, and 8g for the third time, with an interval of 5 minutes between each addition, and mix for 10 minutes after the last addition to obtain a slurry; add 10g of plasticizer (a mixture of epoxidized soybean oil and citrate in a weight ratio of 1:1), 3g of dispersant (a mixture of lecithin and hydroxylated cellulose nanocrystals in a weight ratio of 2:1) and 5g of functional additive (a mixture of benzotriazole, hindered amine and graphene quantum dots in a weight ratio of 1:1:1) to the slurry, continue to mix for 20 minutes, and then transfer to a two-stage extruder, first melt blend at 200°C for 20 minutes, and then melt blend at 160°C for 30 minutes to obtain a sealing material; the sealing material is molded and discharged through a micro-foaming mold with a foaming rate of 6% to obtain a sealing material for doors and windows.

[0073] Comparative Example 1

[0074] Compared with Example 1, the only difference is that the bio-based polyester elastomer of Preparation Example 1 is replaced by polyester fiber; the other steps and conditions remain the same, and finally a sealing material for doors and windows is prepared.

[0075] Comparative Example 2

[0076] Compared with Example 1, the only difference is that the three-level core-shell nano-SiO2 of Preparation Example 2 is replaced by the three-level core-shell nano-SiO2 of Comparative Preparation Example 1; the other steps and conditions remain the same, and finally a sealing material for doors and windows is prepared.

[0077] Comparative Example 3

[0078] Compared with Example 1, the only difference is that the three-level core-shell nano-SiO2 of Preparation Example 2 is replaced by mesoporous nano-SiO2; the other steps and conditions remain the same, and finally a sealing material for doors and windows is prepared.

[0079] The sealing materials for doors and windows prepared in Examples 1-3 and Comparative Examples 1-3 were tested for waterproofness and mechanical properties, including static water contact angle, strength performance, fatigue resistance, and high and low temperature cycle tests. The test method is as follows:

[0080] Static water contact angle: refer to ASTM D7334; use a contact angle meter, 5uL deionized water, 25℃ / 50%RH, measure 5 points for each sample and take the average.

[0081] Strength performance: refer to ISO 37; use a universal material testing machine, tensile rate 500mm / min, temperature 25℃, test tensile strength and elongation at break;

[0082] Fatigue resistance: Refer to ISO 1856, -40℃ to 100℃ cyclic compression 300 times (frequency 1Hz), test its strength retention rate;

[0083] High and low temperature cycle test: -50℃(2h)→100℃(2h) is one cycle, a total of 100 times, refer to ASTM E283 to test the sealing rate attenuation rate.

[0084] The test results are listed in Table 1. Table 1 is as follows:

[0085] Table 1

[0086]

[0087]

[0088] By analyzing the data in Table 1, it can be found that compared with Comparative Examples 1-3, the contact angle of the sealing material for doors and windows prepared in Examples 1-3 is significantly larger, indicating that it has stronger hydrophobicity and better waterproof effect; the tensile strength and elongation at break are significantly higher, indicating that its mechanical properties are better; the strength retention rate is significantly higher, and the sealing attenuation rate is significantly lower, indicating that it has stronger weather resistance.

[0089] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A sealing material for doors and windows, characterized in that: The invention is composed of the following components in parts by weight: 30-40 parts of biomass polyester elastomer, 12-20 parts of tertiary core-shell nano-SiO2, 20-30 parts of vulcanized rubber, 5-10 parts of plasticizer, 1-3 parts of dispersant, and 2-5 parts of functional additive; Among them, the three-level core-shell nano-SiO2 includes an inner core and an inner shell, an intermediate layer and an outer shell that are sequentially coated on the outside of the inner core. The inner core is mesoporous nano-SiO2, the inner shell is perfluoropolyether silane, the intermediate layer is an interwoven network layer formed by C=N bonds, and the outer shell is octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride.

2. The sealing material for doors and windows according to claim 1, characterized in that: The preparation method of the biomass polyester elastomer comprises the following steps: Step A1, mixing castor oil polyol and bio-based furandicarboxylic acid in a weight ratio of 1:(0.5-0.8), and performing a pre-polycondensation reaction at 160-180° C. for 2 h under nitrogen protection; Step A2, then adding tetraisopropyl titanate as a catalyst, raising the temperature to 200-220° C., and carrying out polycondensation reaction under a vacuum degree of 1000 Pa until the viscosity of the reactant reaches 500 Pa.s; Step A3, adding pentaerythritol triacrylate as a regulating agent to the reaction system in portions and continuing the reaction for 4 hours, during which the vacuum degree was reduced from 1000 Pa to 50 Pa in portions; Step A4: Cool the product to 180° C., then add dodecyl epoxysiloxane and react for 20 minutes to finally obtain a biomass polyester elastomer.

3. The sealing material for doors and windows according to claim 2, characterized in that: In step A2, the amount of tetraisopropyl titanate used is 0.02-0.05 wt % of the total amount of castor oil polyol and bio-based furandicarboxylic acid.

4. The sealing material for doors and windows according to claim 2, characterized in that: In step A3, the total amount of pentaerythritol triacrylate is 0.02-0.05wt% of the total amount of castor oil polyol and bio-based furandicarboxylic acid. The pentaerythritol triacrylate is added three times, each addition amount is the same, the time interval between two adjacent additions is 30 minutes, and the corresponding vacuum degrees of the three additions are 1000Pa, 200Pa, and 50Pa, respectively.

5. The sealing material for doors and windows according to claim 1, characterized in that: The preparation method of the three-level core-shell nano-SiO2 has the following steps: Step B1, dispersing perfluoropolyether thiol and mesoporous nano-SiO2 in tetrahydrofuran at a dosage ratio of 2.5 mL: 1 g, adding a photoinitiator, irradiating with 365 nm ultraviolet light for 30 min under nitrogen protection while accompanied by ultrasonic stirring, filtering and washing to obtain F-SiO2; Step B2, γ-aminopropyltriethoxysilane and glycidyl methacrylate were mixed in a molar ratio of 1:2, and hydrolyzed at 60°C for 2 hours, and then F-SiO2 was immersed in the hydrolyzate and stirred for 10 minutes, then taken out, and thermally cured at 120°C to form C=NF-SiO2; Step B3, octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, azobisisobutyronitrile and C=NF-SiO2 are dissolved in toluene at a weight ratio of 100:1:25, and polymerized at 70°C for 6h. After washing and drying, QAS-C=NF-SiO2, i.e., three-level core-shell nano-SiO2, is obtained.

6. The sealing material for doors and windows according to claim 1, characterized in that: The preparation method of the vulcanized rubber is as follows: a nitrile rubber and an isocyanate-terminated polyurethane prepolymer are mixed in a weight ratio of 3:1, and the mixture is subjected to reaction extrusion in a twin-screw extruder at 180-200° C. and a shear rate is controlled at 500-800 s -1 , vulcanization time 30-90 seconds.

7. The sealing material for doors and windows according to claim 1, characterized in that: The plasticizer is a mixture of epoxidized soybean oil and citrate in a weight ratio of 1:

1.

8. The sealing material for doors and windows according to claim 1, characterized in that: The dispersant is a mixture of lecithin and hydroxylated cellulose nanocrystals in a weight ratio of 2:

1.

9. The sealing material for doors and windows according to claim 1, characterized in that: The functional auxiliary agent is a mixture of benzotriazole, hindered amine and graphene quantum dots in a ratio of 1:1:

1.

10. A method for preparing a sealing material for doors and windows according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: Add the biomass polyester elastomer and the vulcanized rubber into an internal mixer in proportion, and mix them at 160° C. for 5 minutes to obtain a premix; Step 2, after the temperature of the premix is ​​raised to 175°C, the three-level core-shell nano-SiO2 is added to the premix in small amounts and multiple times, each time with an interval of 5 minutes, and mixing for 10 minutes after the last addition to obtain a slurry; Step 3: Add plasticizer, dispersant and functional additive to the slurry and continue to mix for 10-20 minutes, then transfer to a two-stage extruder, first melt blend at 180° C. for 20 minutes, then melt blend at 150° C. for 30 minutes to obtain a sealing material; Step 4: The sealing material is molded and discharged through a micro-foaming mold at a foaming rate of 5-8% to obtain a sealing material for doors and windows.

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