Temperature-change-resistant door and window sealing strip material and preparation method thereof

Abstract

The invention relates to the technical field of polyolefin, in particular to a temperature change resistant door and window sealing strip material and a preparation method thereof. Bipolar group grafted metallocene polyolefin particles are used as a core matrix, a zinc source, a filler and an auxiliary are matched, the interface bonding force is enhanced through acid anhydride and epoxy bifunctional group grafting, a dynamic reversible ion network is constructed by adding the zinc source in stages, and the size stability and stress dissipation capacity of the material under temperature alternation are improved. The preparation method comprises the following two steps: melting and mixing to prepare an ionic network pre-composite material, and blending and extruding the ionic network pre-composite material with other components. Test results show that the material has high peel strength, low compression set and excellent weather resistance, and effectively solves the problems of interface failure and deformation increase of a traditional sealing strip in cold and hot cycling.

Description

Technical Field

[0001] This invention relates to the field of polyolefin technology, and in particular to a temperature-resistant door and window sealing strip material and its preparation method. Background Technology

[0002] As a key component of building energy conservation, the long-term weather resistance and dimensional stability of door and window sealing strips directly affect the reliability of the sealing system. Existing sealing strips mostly use EPDM rubber or thermoplastic elastomers as the base material, adjusting hardness and flexibility by adding plasticizers and inorganic fillers. However, under the alternating effects of low winter temperatures in cold regions and high summer temperatures in areas with strong sunlight, the sealing strip is prone to interfacial adhesion degradation: the bonding interface with aluminum alloy or rigid PVC profiles, due to the difference in polarity and mismatch in thermal expansion coefficients, develops micro-cracks after thermal cycling, leading to seal failure. Furthermore, while traditional tackifiers (such as rosin esters or alkylphenol resins) can improve adhesion in the short term, they tend to migrate to the surface during long-term use, not only causing a decrease in interfacial strength but also leading to problems such as stickiness and dust attraction on the sealing strip surface.

[0003] In terms of bulk material properties, conventional sealing strips are difficult to fully recover their original shape after high-temperature compression, exhibiting a high compression set rate, which leads to a decrease in sealing pressure over time. Simultaneously, due to the lag in relaxation behavior of polymer chain segments during temperature alternation, shrinkage easily occurs at the edges of the sealing strip, increasing the resistance to opening doors and windows and causing abnormal noises. Existing technologies attempt to improve heat resistance by increasing crosslinking density or adding rigid fillers, but this often comes at the cost of sacrificing low-temperature flexibility, resulting in a significant increase in hardness at low temperatures and loss of elastic buffering effect. Furthermore, while the direct addition of nanofillers (such as nano-zinc oxide) can enhance UV shielding, untreated nanoparticles tend to aggregate in the matrix, becoming stress concentration points and accelerating cracking during the aging process. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a temperature-resistant door and window sealing strip material and its preparation method, so as to solve the problem that existing door and window sealing strip materials, under long-term hot and cold cycling conditions, are difficult to achieve a synergistic improvement in interfacial bonding strength retention and compression deformation recovery due to insufficient interfacial polarity and lack of bulk dynamic recovery ability, which leads to the early failure of the sealing system in temperature-changing environments.

[0005] To achieve the above objectives, this invention provides a temperature-resistant door and window sealing strip material, comprising a matrix resin, a zinc source, fillers, and additives; wherein, the matrix resin comprises bipolar group-grafted metallocene polyolefin particles, metallocene-catalyzed ethylene-octene copolymer elastomer, and polypropylene, and the molecular chains of the bipolar group-grafted metallocene polyolefin particles are simultaneously grafted with anhydride groups and epoxy groups; the zinc source comprises zinc oxide powder A, zinc oxide powder B, zinc stearate powder, and stearic acid pre-coated nano zinc oxide powder; Furthermore, by weight, the temperature-resistant door and window sealing strip material is prepared from the following raw materials: 4720-4850 parts of the bipolar group-grafted metallocene polyolefin particles, 1800-2500 parts of the metallocene-catalyzed ethylene-octene copolymer elastomer, 2700-3400 parts of the polypropylene, 160-220 parts of zinc oxide powder A, 30-60 parts of zinc oxide powder B, 60-80 parts of zinc stearate powder, 60-100 parts of stearic acid, 40-90 parts of stearic acid pre-coated nano zinc oxide powder, 600-1000 parts of talc, 100-300 parts of carbon black, 300-550 parts of white oil, 20-26 parts of antioxidant 1010, 18-22 parts of antioxidant 168, 25-40 parts of light stabilizer 770, and 25-40 parts of polyethylene wax. Furthermore, the bipolar group-grafted metallocene polyolefin particles are obtained by first grafting maleic anhydride onto a metallocene-catalyzed ethylene-octene copolymer elastomer and then grafting glycidyl methacrylate onto it under the initiation of dicumyl peroxide.

[0006] Furthermore, the average particle size of the zinc oxide powder A is 200-400 μm, and the average particle size of the zinc oxide powder B is 60-120 nm.

[0007] Furthermore, in preparing the bipolar group-grafted metallocene polyolefin particles, the mass ratio of the metallocene-catalyzed ethylene-octene copolymer elastomer, maleic anhydride, glycidyl methacrylate, and dicumyl peroxide is 8000:72-140:36-72:16-28.

[0008] Preferably, the stearic acid pre-coated nano zinc oxide powder is obtained by mixing zinc oxide powder B and stearic acid in a mass ratio of 30-60:10-30.

[0009] Preferably, the metallocene-catalyzed ethylene-octene copolymer elastomer is grade ENGAGE 8150, and the polypropylene is grade T30S.

[0010] Furthermore, the present invention also provides a method for preparing a temperature-sensitive door and window sealing strip material, comprising the following steps: S1: Bipolar group-grafted metallocene polyolefin particles and zinc oxide powder A are melt-mixed in a co-rotating parallel twin-screw extruder. Zinc oxide powder B is added through the 4th side feed, zinc stearate powder is added through the 5th side feed, stearic acid is added through the 6th side feed, and stearic acid pre-coated nano zinc oxide powder is added through the 7th side feed. The mixture is then extruded and granulated to obtain ion network pre-composite particles. S2: Ion network pre-composite material particles are melt-mixed with metallocene-catalyzed ethylene-octene copolymer elastomer, polypropylene, talc, carbon black, white oil, antioxidant 1010, antioxidant 168, light stabilizer 770 and polyethylene wax in a co-rotating parallel twin-screw extruder and then extruded and granulated to obtain temperature-resistant door and window sealing strip material particles.

[0011] Preferably, in step S1, the temperatures of each section of the co-rotating parallel twin-screw extruder are set to 150℃, 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, and 170℃, the screw speed is 160-200 r / min, and the vacuum degree is controlled to -75kPa to -85kPa at the vacuum exhaust port of the 8th section.

[0012] Preferably, in step S2, the temperatures of each section of the co-rotating parallel twin-screw extruder are set to 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, 170℃, and 170℃, the screw speed is 210-240 r / min, and the vacuum degree is controlled to -55kPa to -65kPa at the vacuum exhaust port of the 8th section.

[0013] The beneficial effects of this invention are: This invention constructs multiple reaction sites on the metallocene polyolefin molecular chain through the sequential grafting of acid anhydrides and epoxy bipolar functional groups. The acid anhydride groups form a strong polar interaction with the hydroxyl groups or residual hydrolyzed groups on the profile surface, while the epoxy groups can further undergo ring-opening reactions with carboxyl components, achieving interfacial chemical anchoring. This design significantly enhances the interfacial interaction between the sealing strip and the heterogeneous profile, and the stability of the polar groups is superior to that of small molecule tackifiers, effectively suppressing adhesion attenuation caused by migration.

[0014] By grafting anhydride sites onto a zinc source to form zinc carboxylate ionic bonds, a dynamic and reversible ionic cross-linking network is created within the material. This network can dissociate and recombine under thermal stress, absorbing and dissipating internal stress generated at the interface and in the bulk phase, thereby suppressing the increase of compressive permanent deformation. Simultaneously, the dynamic characteristics of the ionic network endow the sealing strip with a more balanced hardness-temperature profile, avoiding high-temperature softening and low-temperature hardening.

[0015] The zinc source was introduced into the system in stages according to differences in reactivity and function: micron-sized zinc oxide preferentially reacted with grafted anhydride to establish basic ionic crosslinking sites; zinc stearate was subsequently added, adjusting the network density through zinc ion exchange behavior and playing an ionic plasticizing role; while stearate-pre-coated nano-zinc oxide was added at the end of the melt, utilizing its delayed reaction characteristics to enrich on the surface and form a gradient shielding structure. This segmented strategy achieved spatially controllable distribution of ion clusters, improving the synergy between interfacial stability and bulk phase resilience.

[0016] Stearic acid pre-coating reduces the surface energy of nano-zinc oxide, making it easier to migrate to the surface of the product and disperse evenly. This structure not only enhances the UV shielding effect through nanoparticle scattering but also inhibits moisture penetration through the hydrophobic effect of stearic acid chains, thereby improving the weather resistance of the sealing strip under strong sunlight and high humidity. The nano-zinc oxide enriched on the surface further blocks the diffusion of ozone and oxygen, delaying the oxidative degradation of polymer chains. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0018] Example 1: The metallocene-catalyzed ethylene-octene copolymer elastomer used in this embodiment is Dow's ENGAGE 8150 Polyolefin Elastomer, with a typical melt flow rate of 0.50 g / 10 min (190°C / 2.16 kg) and a typical density of 0.868 g / cm³. 3 The polypropylene used was SINOPEC's polypropylene homopolymer PPH-T03 (grade T30S), with a typical melt flow rate of approximately 3 g / 10 min (230°C / 2.16 kg); the polyethylene wax used was Honeywell's A-C617 polyethylene wax; the zinc oxide used was Shanghai Macklin Biochemical Technology Co., Ltd.'s zinc oxide powder A (product number Z767002, 99.8% metals basis, particle size 300±50 nm) and zinc oxide powder B (product number Z820773, 99.8% metals basis, particle size 90±10 nm); the zinc stearate used was Shanghai Macklin Biochemical Technology Co., Ltd.'s zinc stearate (product number Z820683, zinc content 10%-12%); the talc used was Imerys' JetFine® 3CA ultrafine flake talc; and the carbon black used was Cabot's BLACK. PEARLS® 800 specialty carbon black; the white oil used is ExxonMobil Marcol 52 white oil.

[0019] Step S1: 8000g of metallocene-catalyzed ethylene-octene copolymer elastomer was dried at 60℃ for 4h; 96g of maleic anhydride was dried at 50℃ for 2h; 48g of glycidyl methacrylate was dried at 30℃ in the dark for 2h; then, 20g of dicumyl peroxide and 8g of antioxidant 1010 were added to the above 8000g of dried metallocene-catalyzed ethylene-octene copolymer elastomer at room temperature, and the mixture was mixed at low speed with a drum mixer for 20min to obtain a pre-dispersed base resin; the base resin was added to the main feed port of a conventional co-rotating parallel twin-screw extruder, and the barrel was set to feed from the feed... The temperatures at the die head are 150℃, 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, and 170℃ respectively, with a screw speed of 220 r / min. After the main feed inlet stabilizes, 96g of dried maleic anhydride is added to the side feed inlet of the third section of the barrel. After the material passes through the fifth section of the barrel, 48g of dried glycidyl methacrylate is added dropwise to the injection port of the fifth section of the barrel, and vacuum exhaust is turned on in the eighth section of the barrel to -80kPa. The extrudate is water-cooled and granulated to obtain bipolar group-grafted metallocene polyolefin particles. Step S2: Add 40g of zinc oxide B and 20g of stearic acid to a jacketed high-speed mixer, heat the jacket to 90°C and maintain it for 15 minutes; then cool it down to below 40°C and pass it through a 20-mesh sieve to obtain stearic acid pre-coated nano zinc oxide powder. Step S3: 4800g of the bipolar group-grafted metallocene polyolefin obtained in Step S1 and 180g of zinc oxide A are premixed for 10 min and added from the main feed port of a twin-screw extruder. The temperature of the barrel from the feed to the die head is set to 150℃, 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, and 170℃ respectively, and the screw speed is 180 r / min. After the melt at the main feed port stabilizes, 40g of zinc oxide B is added to the side feed port of the 4th section of the barrel. Then, 60g of zinc stearate is added to the side feed port of the 5th section of the barrel. Next, 80g of stearic acid is added to the 6th section of the barrel. Finally, 60g of stearic acid pre-coated nano zinc oxide is added to the side feed port of the 7th section of the barrel. Vacuum exhaust is turned on in the 8th section of the barrel to -80kPa. The extruder is then water-cooled, stretched, and pelletized to obtain ion network pre-composite material particles. Step S4: Add 5220g of ion-linked precomposite material, 2000g of metallocene-catalyzed ethylene-octene copolymer elastomer, and 3200g of polypropylene sequentially to the main feed port of a co-rotating parallel twin-screw extruder. Set the barrel temperature from feed to die head to be 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, 170℃, and 170℃ respectively, and the screw speed to 220r / min; wait for the melt to stabilize. After setting, add 800g of talc powder and 200g of carbon black premixed powder to the side feed port of the 4th section of the barrel; add 400g of white oil to the injection port of the 6th section of the barrel; add 22g of antioxidant 1010, 20g of antioxidant 168, 30g of light stabilizer 770 and 30g of polyethylene wax to the side feed port of the 8th section of the barrel, and open the vacuum exhaust to -60kPa in the 8th section of the barrel; extrude the strips, water cool and pelletize to obtain temperature-resistant composite material granules for door and window sealing strips; Step S5: Take the temperature-resistant composite material granules for door and window sealing strips, and extrude them using a conventional door and window sealing strip extrusion production line. The barrel temperature is set sequentially from the feed to the die head as 160℃, 170℃, 175℃, and 175℃, and the screw speed is 30r / min. After extrusion, the material is shaped in a vacuum setting section with a vacuum degree of -70kPa, and then cooled in a 20℃ circulating water cooling tank. The traction speed is 2m / min, and the material is cut to length according to the cross-sectional requirements of the door and window sealing strip to obtain the temperature-resistant door and window sealing strip material.

[0020] Example 2: Compared to Example 1, in step S1, the amount of maleic anhydride was adjusted to 120g, the amount of glycidyl methacrylate was adjusted to 60g, the amount of dicumyl peroxide was adjusted to 24g, the amount of antioxidant 1010 was adjusted to 10g, the screw speed in step S1 was adjusted to 240r / min, and the vacuum degree of the 8th stage vacuum exhaust port was adjusted to -85kPa; in step S2, the amount of zinc oxide B powder was adjusted to 50g, the amount of stearic acid was adjusted to 25g, resulting in 75g of stearic acid pre-coated nano zinc oxide powder; in step S3, the amount of zinc oxide powder A was adjusted to 200g, the amount of zinc oxide B powder was adjusted to 50g, and the amount of zinc stearate powder was adjusted to 70g. The amount of stearic acid pre-coated nano-zinc oxide powder obtained in S2 was adjusted to 75g, and the amount of bipolar group-grafted metallocene polyolefin particles was adjusted accordingly to 4745g to maintain the total feed amount in step S3 at 5220g. Simultaneously, the screw speed in step S3 was adjusted to 190r / min. In step S4, the amount of metallocene-catalyzed ethylene-octene copolymer elastomer was adjusted to 2200g, the amount of polypropylene to 3000g, the amount of talc to 700g, the amount of carbon black to 180g, the amount of white oil to 450g, the amount of antioxidant 1010 to 24g, and the amount of light stabilizer 770 to 35g. The screw speed in step S4 was adjusted to 230r / min. All other conditions were the same as in Example 1.

[0021] Example 3: Compared with Example 1, in step S1, the amount of maleic anhydride was adjusted to 72g, the amount of glycidyl methacrylate was adjusted to 36g, the amount of dicumyl peroxide was adjusted to 16g, the amount of antioxidant 1010 was adjusted to 6g, the screw speed in step S1 was adjusted to 200r / min, and the vacuum degree of the 8th stage vacuum exhaust port was adjusted to -70kPa; in step S2, the amount of zinc oxide B powder was adjusted to 30g, the amount of stearic acid was adjusted to 10g, and 40g of stearic acid pre-coated nano zinc oxide powder was obtained; in step S3, the amount of zinc oxide powder A was adjusted to 160g, the amount of zinc oxide B powder was adjusted to 30g, the amount of zinc stearate powder was adjusted to 80g, the amount of stearic acid was adjusted to 60g, the amount of stearic acid pre-coated nano zinc oxide powder obtained in step S2 was adjusted to 40g, and the bipolar group The amount of grafted metallocene polyolefin particles was adjusted to 4850g to maintain the total feed amount in step S3 at 5220g. Simultaneously, the screw speed in step S3 was adjusted to 160r / min, and the vacuum level at the 8th stage vacuum exhaust port was adjusted to -75kPa. In step S4, the amount of metallocene-catalyzed ethylene-octene copolymer elastomer was adjusted to 2500g, polypropylene to 2700g, talc to 600g, carbon black to 150g, white oil to 350g, antioxidant 1010 to 20g, antioxidant 168 to 18g, light stabilizer 770 to 25g, and polyethylene wax to 25g. The screw speed in step S4 was adjusted to 210r / min, and the vacuum level at the 8th stage vacuum exhaust port was adjusted to -55kPa. All other conditions were the same as in Example 1.

[0022] Example 4: Compared to Example 1, in step S1, the amount of glycidyl methacrylate was adjusted to 72g; in step S2, the amount of zinc oxide B powder was adjusted to 60g, and the amount of stearic acid was adjusted to 30g, resulting in 90g of stearic acid pre-coated nano-zinc oxide powder; in step S3, the amount of zinc stearate powder was adjusted to 80g, the amount of stearic acid was adjusted to 100g, the amount of stearic acid pre-coated nano-zinc oxide powder obtained in step S2 was adjusted to 90g, and the amount of bipolar group-grafted metallocene polyolefin particles was correspondingly adjusted to 4730g to maintain the total feed amount in step S3 at 5220g, while the screw speed in step S3 was adjusted to 200r / min; in step S4, the amount of white oil was adjusted to 550g, and the amount of polyethylene wax was adjusted to 40g. All other conditions were the same as in Example 1.

[0023] Example 5: Compared to Example 1, in step S1, the amount of maleic anhydride was adjusted to 140g, the amount of glycidyl methacrylate was adjusted to 72g, the amount of dicumyl peroxide was adjusted to 28g, the amount of antioxidant 1010 was adjusted to 10g, the screw speed in step S1 was adjusted to 260r / min, and the vacuum degree of the 7th stage vacuum exhaust port was adjusted to -90kPa; in step S2, the amount of zinc oxide B powder was adjusted to 45g, the amount of stearic acid was adjusted to 25g, resulting in 70g of stearic acid pre-coated nano zinc oxide powder; in step S3, the amount of zinc oxide powder A was adjusted to 220g, the amount of zinc oxide B powder was adjusted to 60g, the amount of zinc stearate powder was adjusted to 70g, the amount of stearic acid pre-coated nano zinc oxide powder obtained in step S2 was adjusted to 70g, and the bipolar The amount of metallocene-grafted polyolefin particles was adjusted to 4720g to maintain a total feed amount of 5220g in step S3. Simultaneously, the screw speed in step S3 was adjusted to 200r / min, and the vacuum level at the 8th stage vacuum exhaust port was adjusted to -85kPa. In step S4, the amount of metallocene-catalyzed ethylene-octene copolymer elastomer was adjusted to 1800g, polypropylene to 3400g, talc to 900g, carbon black to 300g, white oil to 350g, antioxidant 1010 to 26g, antioxidant 168 to 22g, and light stabilizer 770 to 40g. The screw speed in step S4 was adjusted to 240r / min, and the vacuum level at the 8th stage vacuum exhaust port was adjusted to -65kPa. All other conditions were the same as in Example 1.

[0024] Example 6: Compared to Example 1, in step S1, the amount of maleic anhydride was adjusted to 88g; in step S3, the amount of zinc oxide powder A was adjusted to 200g, the amount of stearic acid was adjusted to 70g, and the amount of bipolar group-grafted metallocene polyolefin particles was adjusted accordingly to 4790g to maintain the total amount of feed in step S3 at 5220g; in step S4, the amount of metallocene-catalyzed ethylene-octene copolymer elastomer was adjusted to 1900g, the amount of polypropylene was adjusted to 3300g, the amount of talc was adjusted to 1000g, the amount of carbon black was adjusted to 100g, the amount of white oil was adjusted to 300g, and the amount of polyethylene wax was adjusted to 25g. All other conditions were the same as in Example 1.

[0025] Comparative Example 1: The difference from Example 1 is that 48g of glycidyl methacrylate is not injected in step S1, while the other conditions are the same as in Example 1.

[0026] Comparative Example 2: The difference from Example 1 is that in step S1, 96g of maleic anhydride, 48g of glycidyl methacrylate, 20g of dicumyl peroxide and 8g of antioxidant 1010 are added through the side feed port of the third section of the barrel after premixing for 10 minutes. Glycidyl methacrylate is no longer injected into the screw extruder injection port of the fifth section of the barrel. The other conditions are the same as in Example 1.

[0027] Comparative Example 3: The difference from Example 1 is that in step S3, 40g of zinc oxide B powder, 60g of zinc stearate powder, and 60g of stearic acid pre-coated nano zinc oxide powder obtained in step S2 are all added simultaneously through the main feed port along with bipolar group-grafted metallocene polyolefin particles and zinc oxide powder A, instead of being added in segments through the 4th, 5th, and 7th side feed ports. The other conditions are the same as in Example 1.

[0028] Comparative Example 4: The difference from Example 1 is that 60g of zinc stearate powder is not added in step S3, and the amount of bipolar group-grafted metallocene polyolefin particles in step S3 is adjusted from 4800g to 4860g to keep the total amount of material added in step S3 at 5220g. The other conditions are the same as in Example 1.

[0029] Comparative Example 5: The difference from Example 1 is that: in step S2, instead of preparing stearic acid pre-coated nano zinc oxide powder, 40g of zinc oxide B powder and 20g of stearic acid are directly added to the side feed port of the 7th section in step S3, and the other conditions are the same as in Example 1.

[0030] Comparative Example 6: The difference from Example 1 is that: in step S3, 180g of zinc oxide powder A, 40g of zinc oxide powder B, 60g of zinc stearate powder and 60g of stearic acid pre-coated nano zinc oxide powder obtained in step S2 are not added, and the amount of bipolar group grafted metallocene polyolefin particles in step S3 is adjusted from 4800g to 5140g to keep the total amount of material added in step S3 at 5220g. The other conditions are the same as in Example 1.

[0031] Comparative Example 7: The difference from Example 1 is that in step S1, 96g of maleic anhydride, 48g of glycidyl methacrylate, 20g of dicumyl peroxide, and 8g of antioxidant 1010 are not added. Instead, the dried metallocene-catalyzed ethylene-octene copolymer elastomer is directly extruded in a co-rotating parallel twin-screw extruder at the same temperature and screw speed as in step S1 of Example 1, and then water-cooled and pelletized to obtain metallocene-catalyzed ethylene-octene copolymer elastomer particles. These particles are used in place of the bipolar group-grafted metallocene polyolefin particles obtained in step S1 of Example 1 for step S3, and the remaining conditions are the same as in Example 1.

[0032] Performance testing: Sample preparation: The temperature-resistant variable sealing strip material particles obtained in Examples 1-6 and Comparative Examples 1-7 were extruded into solid door and window sealing strip products on the same conventional door and window sealing strip extrusion production line according to their respective corresponding steps S5. To ensure comparability, all samples used the same die and the extruder temperature was uniformly set to 160℃-170℃, screw speed to 30r / min, vacuum setting vacuum degree to -0.05MPa, and traction speed to 2m / min. After extrusion, the door and window sealing strip products were placed in an environment of (23±2)℃ and (50±5)% relative humidity for 72h before being sampled for the following intrinsic characterization and application performance tests.

[0033] 90° peel strength and retention rate after thermal cycling: Peel strength was tested according to GB / T 7760-2003. Rigid PVC sheet and aluminum alloy sheet were selected as rigid substrates, with substrate dimensions of 150mm×50mm×2mm. Before testing, the substrates were cleaned with isopropanol and dried in an oven at 60℃ for 30min. Each sample particle was hot-pressed into a 2.0mm thick sheet at 190℃ (pressure 10MPa, holding pressure for 5min), cut into strips 25mm wide and 150mm long, and hot-pressed onto the rigid substrate at 190℃ and 2.0MPa for 3min. After cooling to 23℃, peel samples were formed. A 90° peel fixture was used on an electronic universal testing machine at a peel speed of 100mm / min. The average peel force within a stable peel section of 50mm was recorded and converted into peel strength (N / mm). Five strips were tested for each sample and each substrate, and the average was taken. Thermal cycling treatment was performed according to GB / T Test N was performed according to 2423.22-2012. The cycle consisted of holding at -30℃ for 2 hours, raising the temperature to 70℃ (heating and cooling time 10 min) and holding for 2 hours. A total of 20 cycles were performed. After each cycle, the product was placed at (23±2)℃ and (50±5)% relative humidity for 24 hours. The peel strength was then tested again using the method described above, and the retention rate (%) was calculated as follows: peel strength after cycle / peel strength before cycle × 100%.

[0034] Compression set: Compression set test was conducted according to GB / T 7759.1-2015. Each sample of door and window sealing strip was hot-pressed into a 12.5mm thick plate and punched to obtain a cylindrical specimen with a diameter of 29mm. The specimen was placed at (23±2)℃ and (50±5)% relative humidity for 24h. The specimen was placed in a compression device and compressed to a compression ratio of (25±2)%, and kept in a constant temperature chamber at 70℃ for 24h. After being removed, it was placed at (23±2)℃ for 30min for unloading, and then placed for another 30min. The height change was measured and the compression set (%) was calculated. Three specimens were tested for each sample and the average was taken.

[0035] Hardness variation (-20℃, 0℃, 23℃, 70℃): The hardness variation test was carried out according to the provisions of 6.2.6 in GB / T 24498-2025. Each sample of door and window sealing strip products was hot-pressed into test pieces with a diameter of not less than 30mm and a thickness of not less than 6mm. The test pieces were placed at (23±2)℃ and (50±5)% relative humidity for 24h. The test pieces were then placed in constant temperature environments of -20℃±2℃, 0℃±2℃, 23℃±2℃, and 70℃±2℃ for 2h respectively. After removal, the Shore hardness A was determined within 10s according to the method specified in GB / T 531.1-2008, and the hardness difference at different temperature ranges was calculated.

[0036] Heating shrinkage rate (dimensional shrinkage rate): The heating shrinkage rate test shall be carried out in accordance with the provisions of 6.5.3 in GB / T 24498-2025. Three samples with a length of 110mm±10mm shall be cut from each sample door and window sealing strip product. Two points with a distance of 100mm±1mm shall be marked on the sample. The distance S0 between the two points shall be measured with a measuring instrument with a graduation value of 0.02mm. The sample shall be placed horizontally on a glass plate and placed in an electric heating drying oven at 70℃±2℃ for 24h. After being taken out, it shall be placed on a glass plate under standard temperature conditions and left to stand for 2h. The distance S1 between the two points shall be measured again. The result shall be calculated as Sr=(S0-S1) / S0×100% and the arithmetic mean of the three samples shall be taken.

[0037] Weight loss upon heating: The weight loss upon heating was tested according to the provisions of 6.5.4 in GB / T 24498-2025. Five samples with a mass of 5g±0.5g were cut from each sample of door and window sealing strip products. The mass m0 was weighed (accurate to 0.0001g). The samples were placed in an electric heating drying oven at 100℃±2℃ for 168h±1h. After being removed, they were placed in a desiccator to cool to the ambient temperature and then weighed again (accurate to 0.0001g). The weight loss upon heating was calculated as mr=(m0-m1) / m0×100% and the arithmetic mean of the five samples was taken.

[0038] Ozone aging resistance and photoaging performance: Ozone aging resistance was conducted according to the specifications in GB / T 24498-2025, section 6.5.7.1, and with reference to the method in GB / T 7762-2014. The test conditions were an ozone concentration of 500 × 10⁻⁶. -6 ±50×10 -6)The test temperature was 40℃±2℃, the test time was 168h±1h, the sample length was 100mm±10mm, and the elongation was 20%±2%. After aging, the cracking was observed and judged using a 5x magnifying glass. Light aging was performed according to GB / T 24498-2025, 6.5.7.2, and GB / T 16422.2-2022, Table 3, cycle 1. Four samples with a length of 110mm±10mm were cut from each sample of door and window sealing strips. One sample was sealed away from light, and the other three samples were placed in an aging chamber for light aging. After the test, the appearance was observed and compared with the sealed sample to evaluate the color change level. The aged samples were then placed under standard temperature and humidity conditions for 24h±0.5h. Two lines with a spacing of 50mm±1mm were drawn in the middle of the sample. The process was carried out according to GB / T... According to method 528-2009, the distance between the markings is stretched to 75mm±5mm at a test speed of (500±50)mm / min and held for 3min, and the fracture of the specimen is observed.

[0039] Table 1 Summary of performance test results for examples and comparative examples

[0040] As can be seen from the data in Table 1, the door and window sealing strip material prepared by this invention exhibits a high overall level in terms of interfacial peel strength and retention rate after thermal cycling. Simultaneously, compression set, dimensional shrinkage, and heating weight loss are all kept within a low range, hardness difference is effectively controlled, and the appearance remains stable after ozone and light aging, achieving tensile strength without cracking. This may be because the metallocene-catalyzed ethylene-octene copolymer elastomer, after grafting with bipolar functional groups via maleic anhydride and then glycidyl methacrylate, possesses both anhydride and epoxy polar groups on its chain segments. This results in stronger polarity and reactive fixation when in contact with aluminum alloys and rigid PVC. Furthermore, the zinc carboxylate ionic bonds and reversible ionic network constructed from zinc oxide, zinc stearate, and stearic acid enable dynamic dissociation and recombination of the material under temperature alternation and compressive deformation, achieving stress dissipation and inhibiting component migration, thus balancing interfacial stability and bulk dimensional stability.

[0041] As can be seen from the data in Table 1 of Example 1 and Comparative Examples 1 and 2, when glycidyl methacrylate grafting is missing in step S1, or when maleic anhydride and glycidyl methacrylate are added all at once in the early stage, the interfacial peel strength and its retention rate show a decreasing trend, and the compression set and dimensional shrinkage are more likely to increase. The main reason may be that the reaction sites of epoxy polar groups are reduced or unevenly distributed, resulting in insufficient chemical fixation of the interface; at the same time, the effective utilization of anhydride sites is limited, making it difficult for the subsequent zinc carboxylate ionic bonds to form a continuous and stable interaction structure near the interface, making it difficult to achieve both interfacial stability and stress dissipation under thermal cycling stress.

[0042] As can be seen from the data in Table 1 for Example 1 and Comparative Examples 3 and 4, when zinc oxide B, zinc stearate, and stearic acid-coated nano-zinc oxide are no longer added in stages, or when zinc stearate is absent, the overall performance of indicators such as peel retention rate, compression set, and hardness difference deteriorates, and the nano-zinc oxide is more prone to fracture after photoaging. This may be because the addition sites and timing of the zinc source and stearic acid are altered, disturbing the nucleation and rearrangement of zinc carboxylate ion clusters, making the ion network more prone to localized over-crosslinking or uneven dispersion. Simultaneously, the lack of ion exchange and migration channels provided by zinc stearate makes it difficult to fully dissipate the stress from thermal cycling through dynamic dissociation and recombination, resulting in the coexistence of interfacial microcracks and bulk hardening.

[0043] As can be seen from the data in Example 1 and Comparative Example 5 in Table 1, when stearic acid pre-coating of nano-zinc oxide is not used and the subsequent addition is omitted, although some interface and deformation indicators can still be maintained within the usable range, the color change level under photoaging decreases and the tensile non-fracture requirement is difficult to meet. The main reason may be that the surface energy and reactivity of nano-zinc oxide are not pre-controlled, making it easy to agglomerate in the melt and form local enrichment areas, thereby accelerating the initiation of microcracks during photoaging; at the same time, it is difficult to construct a surface-enriched micro-shielding structure, so that weather resistance and appearance retention cannot be improved simultaneously through a single adjustment.

[0044] As can be seen from the data in Example 1 and Comparative Examples 6 and 7 in Table 1, when zinc oxide A, zinc oxide B, zinc stearate, and stearic acid pre-coated nano zinc oxide are removed in step S3, leaving only bipolar functional group grafting, or when maleic anhydride and glycidyl methacrylate grafting are further removed, the peel strength and its retention rate are significantly reduced, while the compression set, hardness difference, and dimensional shrinkage are significantly increased. This may be because the lack of zinc carboxylate ionic bonds generated in situ from the grafted anhydride sites and the zinc oxide / zinc source results in insufficient reversible ionic crosslinking points to achieve dynamic dissipation under pressure and temperature alternation. Simultaneously, the reduction in reactive sites at the interface leads to a decrease in the interaction forces with aluminum alloys and rigid PVC, preventing the simultaneous improvement of interface stability and bulk recovery through a single modification. This demonstrates the synergistic effect of bipolar functional group grafting and reversible ionic networks, where 1+1 is greater than 2.

[0045] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A temperature-sensitive door and window sealing strip material, characterized in that, The product comprises a matrix resin, a zinc source, fillers, and additives; wherein the matrix resin comprises bipolar group-grafted metallocene polyolefin particles, metallocene-catalyzed ethylene-octene copolymer elastomer, and polypropylene, and the molecular chains of the bipolar group-grafted metallocene polyolefin particles are simultaneously grafted with anhydride groups and epoxy groups; the zinc source comprises zinc oxide powder A, zinc oxide powder B, zinc stearate powder, and stearic acid pre-coated nano zinc oxide powder. The temperature-resistant door and window sealing strip material, by weight, is prepared from the following raw materials: 4720-4850 parts of the bipolar group-grafted metallocene polyolefin particles, 1800-2500 parts of the metallocene-catalyzed ethylene-octene copolymer elastomer, 2700-3400 parts of the polypropylene, 160-220 parts of zinc oxide powder A, 30-60 parts of zinc oxide powder B, 60-80 parts of zinc stearate powder, 60-100 parts of stearic acid, 40-90 parts of stearic acid pre-coated nano zinc oxide powder, 600-1000 parts of talc, 100-300 parts of carbon black, 300-550 parts of white oil, 20-26 parts of antioxidant 1010, 18-22 parts of antioxidant 168, 25-40 parts of light stabilizer 770, and 25-40 parts of polyethylene wax.

2. The temperature-resistant door and window sealing strip material according to claim 1, characterized in that, The bipolar group-grafted metallocene polyolefin particles were obtained by grafting maleic anhydride onto a metallocene-catalyzed ethylene-octene copolymer elastomer first and then onto glycidyl methacrylate under the initiation of dicumyl peroxide.

3. The temperature-resistant door and window sealing strip material according to claim 1, characterized in that, The average particle size of zinc oxide powder A is 200-400 μm, and the average particle size of zinc oxide powder B is 60-120 nm.

4. The temperature-resistant door and window sealing strip material according to claim 2, characterized in that, When preparing the bipolar group-grafted metallocene polyolefin particles, the mass ratio of the metallocene-catalyzed ethylene-octene copolymer elastomer, maleic anhydride, glycidyl methacrylate, and dicumyl peroxide is 8000:72-140:36-72:16-28.

5. The temperature-resistant door and window sealing strip material according to claim 1, characterized in that, The stearic acid pre-coated nano zinc oxide powder is obtained by mixing zinc oxide powder B and stearic acid in a mass ratio of 30-60:10-30.

6. The temperature-resistant door and window sealing strip material according to claim 1, characterized in that, The metallocene-catalyzed ethylene-octene copolymer elastomer is designated ENGAGE 8150, and the polypropylene is designated T30S.

7. A method for preparing a temperature-resistant door and window sealing strip material according to any one of claims 1-6, characterized in that, Includes the following steps: S1: Bipolar group-grafted metallocene polyolefin particles and zinc oxide powder A are melt-mixed in a co-rotating parallel twin-screw extruder. Zinc oxide powder B is added through the 4th side feed, zinc stearate powder is added through the 5th side feed, stearic acid is added through the 6th side feed, and stearic acid pre-coated nano zinc oxide powder is added through the 7th side feed. The mixture is then extruded and granulated to obtain ion network pre-composite particles. S2: Ion network pre-composite material particles are melt-mixed with metallocene-catalyzed ethylene-octene copolymer elastomer, polypropylene, talc, carbon black, white oil, antioxidant 1010, antioxidant 168, light stabilizer 770 and polyethylene wax in a co-rotating parallel twin-screw extruder and then extruded and granulated to obtain temperature-resistant door and window sealing strip material particles.

8. The method for preparing the temperature-resistant door and window sealing strip material according to claim 7, characterized in that, In step S1, the temperatures of each section of the co-rotating parallel twin-screw extruder are set to 150℃, 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, and 170℃, the screw speed is 160-200 r / min, and the vacuum degree is controlled to -75kPa to -85kPa at the vacuum exhaust port of the 8th section.

9. The method for preparing the temperature-resistant door and window sealing strip material according to claim 7, characterized in that, In step S2, the temperatures of each section of the co-rotating parallel twin-screw extruder are set to 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, 170℃, and 170℃, respectively, and the screw speed is 210-240 r / min. The vacuum degree is controlled to -55 kPa to -65 kPa at the vacuum exhaust port of the 8th section.

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