Dense hole-forming sealing rubber strip and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and particularly discloses a dense hole-forming sealing rubber strip and a preparation method thereof. The dense hole-forming sealing rubber strip comprises the following raw materials in parts by mass: 90-110 parts of ethylene propylene diene monomer, 60-90 parts of carbon black, 10-20 parts of white carbon black, 5-8 parts of zinc oxide, 1-3 parts of stearic acid, 40-60 parts of paraffin oil, 0.5-1 part of polyethylene glycol, 2-3 parts of magnesium oxide, 3-5 parts of a vulcanization system, 1-1.5 parts of a mildew preventive and 3-6 parts of a microporous foaming agent. The dense hole-forming sealing rubber strip has the advantage that the mechanical property of the sealing rubber strip can be improved under the condition that the sealing performance is not affected.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and more specifically, to a dense pore sealing strip and a preparation method thereof. Background Art

[0002] Lightweight sealing strip microporous foam material is a new type of sealing material that is widely used in interior wooden doors. Compared with traditional sealing materials, microporous foam material has a lower density, which can effectively reduce the overall weight and improve the energy efficiency and performance of the product. Usually, microporous foam material is prepared with ethylene propylene diene monomer rubber (EPDM) as raw material. As a weather-resistant, insulating and flexible rubber material, it has been widely used in sealing rubber rings and other fields.

[0003] In order to obtain lightweight sealing strips, it is usually achieved by reducing fillers, foaming or replacing low-density materials, but this may destroy the microstructure and component ratio of the material, thereby reducing the cross-linking density, weakening the elasticity and rebound properties, and making it difficult to return to its original shape after being compressed, resulting in deformation, thereby affecting the sealing performance of the sealing strip. Summary of the Invention

[0004] In order to improve the mechanical properties of a sealing strip without affecting the sealing performance, the present application provides a dense pore sealing strip and a preparation method thereof.

[0005] The present application provides a dense pore sealing strip and a preparation method thereof, which adopts the following technical solutions: In the first aspect, the present application provides a dense pore sealing strip, which comprises the following raw materials in parts by weight: 90-110 parts of EPDM rubber, 60-90 parts of carbon black, 10-20 parts of white carbon black, 5-8 parts of zinc oxide, 1-3 parts of stearic acid, 40-60 parts of paraffin oil, 0.5-1 part of polyethylene glycol, 2-3 parts of magnesium oxide, 3-5 parts of vulcanization system, 1-1.5 parts of mildew inhibitor, and 3-6 parts of microporous foaming agent.

[0006] Through the synergistic reinforcement of EPDM rubber and carbon black, a rigid-flexible composite structure is formed to ensure the high elasticity and tensile strength of the sealing strip. The introduction of white carbon black can reduce the density of the sealing strip. At the same time, bidirectional fillers can reduce stress concentration and improve tear resistance. Zinc oxide and stearic acid synergistically optimize the vulcanization efficiency to form a uniform cross-linked network, thereby improving the heat resistance and mechanical properties of the strip. Paraffin oil can reduce hardness without excessively sacrificing strength. Polyethylene glycol ensures uniform distribution of fillers and is not prone to local weaknesses. The vulcanization system can form uniform cross-linking bonds, giving the strip a higher cross-linking density, which is beneficial to improving the strip's resistance to deformation and resilience. The microporous foaming agent forms a uniform closed-cell structure, which can effectively block the penetration of water vapor and dust, which is beneficial to long-term sealing effect. The mildew inhibitor provides the strip with antibacterial function, which is beneficial to enhancing the mildew resistance and durability of the strip.

[0007] Preferably, the vulcanization system is a peroxide vulcanizing agent, and the peroxide vulcanizing agent is one of alkyl peroxide and diacyl peroxide.

[0008] Since peroxide vulcanizers can decompose to generate free radicals at high temperatures, they can initiate the formation of carbon-carbon cross-links between EPDM rubber molecular chains. Compared with the polysulfide bonds formed by traditional sulfur vulcanization systems, carbon-carbon bonds have higher bond energy and stronger thermal stability, which is beneficial to improving the heat resistance and aging resistance of the rubber strips. The cross-linked network is not easily broken under high temperature or long-term use, which leads to performance degradation. At the same time, peroxide vulcanizers have high reaction activity and can form a uniform and dense cross-linked network in EPDM rubber.

[0009] Preferably, the peroxide vulcanizing agent is one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and dilauroyl peroxide.

[0010] Since 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and dilauroyl peroxide can form carbon-carbon cross-linked bonds through free radical reactions, the bond energy is significantly higher than the polysulfide bonds of traditional sulfur vulcanization, and the uniform cross-linking rate of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and dilauroyl peroxide makes it difficult for the microcellular foaming agent to over-expand, thereby making the microcellular structure dense and uniform, maintaining the sealing performance.

[0011] Preferably, the paraffin oil is a paraffin oil with a flash point above 280° C. and an aromatic hydrocarbon content of 0%.

[0012] Since paraffin oil with a flash point above 280°C is almost non-volatile during high-temperature mixing and vulcanization, it is less likely to cause an imbalance in the formula ratio due to oil loss, making the density and performance of the rubber strip uniform. The absence of volatile residue makes it difficult for oil to migrate to the surface of the pore wall after vulcanization, and the microporous structure is not easily collapsed due to oil leakage, maintaining the integrity of the closed cell and ensuring long-term sealing effect. Aromatic hydrocarbons are toxic and carcinogenic, so paraffin oil with 0% aromatic content makes it difficult for the rubber strip to release harmful substances after use or disposal.

[0013] Preferably, the mildew inhibitor comprises the following raw materials: 1-5 g of modified nano zinc oxide, 15-25 g of 3-iodo-2-propynyl butyl carbamate, 25-25.7 ml of anhydrous ethanol, and 55-65 ml of deionized water.

[0014] Since modified nano-zinc oxide can destroy microbial cell membranes and inhibit enzyme activity by releasing zinc ions, it can achieve efficient mildew prevention, while 3-iodo-2-propynylbutyl carbamate penetrates microbial cell membranes, oxidizes proteins and nucleic acids, and has a rapid killing effect on fungi and bacteria. It also forms a dual antibacterial mechanism with modified nano-zinc oxide, expanding the antibacterial spectrum and delaying the development of drug resistance.

[0015] Preferably, the preparation method of the mildew inhibitor comprises the following steps: weighing 15-25 g of 3-iodo-2-propynyl butyl carbamate into a beaker, adding 25-25.7 ml of anhydrous ethanol and 55-65 ml of deionized water, stirring until the 3-iodo-2-propynyl butyl carbamate is completely dissolved to obtain a mixed solution, weighing 1-5 g of modified nano zinc oxide and adding it to 10-50 ml of the mixed solution for ultrasonic dispersion treatment, then placing the mixture into a vacuum drying oven, and evacuating the vacuum dryer to -0.06 to -0.12 MPa, blending for 0.5-1.5 h, standing for 25-35 min, taking out the mixture, and then centrifuging at a speed of 2500-3500 r / min. Finally, drying the mixture in an oven at 25-35° C. for 10-14 h to obtain the mildew inhibitor.

[0016] Preferably, the modified nano zinc oxide comprises the following raw materials: 3-7 g nano zinc oxide, 490-710 ml N,N-dimethylformamide, 3-9 mL 3-aminopropyltriethoxysilane, 5-7 g β-cyclodextrin, and 5-7 mL 1,1-carbonyldiimidazole.

[0017] Due to the strong polarity of the nano-oxidized surface, its compatibility with non-polar EPDM rubber is poor. 3-Aminopropyltriethoxysilane undergoes a hydrolysis-condensation reaction with the hydroxyl groups on the surface of nano-zinc oxide to form a stable Si-O-Zn covalent bond, constructing an amino-functionalized layer on the surface of the nanoparticles, which can combine with the polar regions of the EPDM rubber, reduce interfacial repulsion, and thus improve the compatibility between nano-zinc oxide and EPDM rubber. The hydrophobic cavity of β-cyclodextrin wraps around the 3-aminopropyltriethoxysilane-modified nano-zinc oxide through host-guest interaction, forming a physical barrier, making it difficult for the particles to directly contact and agglomerate. 1,1-Carbonyldiimidazole activates the hydroxyl groups of β-cyclodextrin to generate an active imidazole ester intermediate, which undergoes an amidation reaction with the amino groups of 3-aminopropyltriethoxysilane, anchoring the nanoparticles in the hydrophobic cavity of cyclodextrin, further reducing the interfacial tension with the non-polar segments of the EPDM rubber.

[0018] Preferably, the preparation method of the modified nano zinc oxide is as follows: 3-7g of nano zinc oxide is dispersed in 150-250ml N, N-dimethylformamide, stirred for 10-20min and ultrasonically oscillated for 0.5-1.5h, then 3-9mL of 3-aminopropyltriethoxysilane is added dropwise, stirred at 85-95°C for 5-7h, cooled to 20-30°C, centrifuged at 3500-4500r / min for 8-12min, and the separated solid particles are washed with N, N-dimethylformamide and deionized water, and then placed in a vacuum drying oven at 35-45°C for 2-4 days for grinding to obtain an intermediate product; 5-7g of β-cyclodextrin is dissolved in 180-220mL of N, N-dimethylformamide, and then 5-7mL of 1,1-carbonyldiimidazole is magnetically stirred at 20-30°C for 1-3 hours to obtain an activated β-cyclodextrin solution; the intermediate product is dispersed in 160-240 mL of N,N-dimethylformamide, the activated β-cyclodextrin solution is slowly added dropwise thereto, and the mixture is stirred at 20-30°C for 15-25 hours, and washed with N,N-dimethylformamide and deionized water. The mixture is placed in a drying oven and dried at 55-65°C for 1-3 days, and then ground to obtain modified nano-zinc oxide.

[0019] In a second aspect, the present application provides a method for preparing a dense pore sealing strip, which adopts the following technical solution: A method for preparing a dense pore sealing strip comprises the following steps: S1: First, after pressurizing and kneading 90-110 parts of EPDM rubber, 60-90 parts of carbon black, 10-20 parts of white carbon black, 5-8 parts of zinc oxide, 1-3 parts of stearic acid, 0.5-1 part of polyethylene glycol, and 20-30 parts of paraffin oil are added in sequence, kneaded evenly, and then discharged at a discharge temperature of 145-155°C. The product is discharged, cooled, and stored to obtain an intermediate; S2: The intermediate obtained in S1 is allowed to stand for 22-26 hours and then mixed. Then, 2-3 parts of magnesium oxide, 3-5 parts of vulcanization system, 1-1.5 parts of mildew inhibitor, and 3-6 parts of microporous foaming agent are added and mixed. The discharge temperature is controlled at 80-100°C, and the roller distance during thin pass is 1-1.5mm to obtain a mixed rubber. S3: The rubber compound is extruded from a specific mold in a rubber extruder and placed in molten salt at 250-280°C, isolated from air for vulcanization; S4: After the reaction is completed, the product is cooled, formed, and welded to the entire frame.

[0020] In summary, this application has the following beneficial effects: 1. Through the synergistic reinforcement of EPDM rubber and carbon black, a rigid-flexible composite structure is formed to ensure the high elasticity and tensile strength of the sealing strip. The introduction of white carbon black can reduce the density of the sealing strip. At the same time, the bidirectional filler reduces stress concentration and improves tear resistance. Zinc oxide and stearic acid synergistically optimize the vulcanization efficiency to form a uniform cross-linked network, thereby improving the heat resistance and mechanical properties of the strip. Paraffin oil can reduce hardness without excessively sacrificing strength. Polyethylene glycol ensures uniform distribution of fillers and is not prone to local weaknesses. The vulcanization system can form uniform cross-linking bonds, giving the strip a higher cross-linking density, which is beneficial to improving the strip's resistance to deformation and resilience. The microporous foaming agent forms a uniform closed-cell structure, which can effectively block the penetration of water vapor and dust, which is beneficial to long-term sealing effect. The mildew inhibitor provides the strip with antibacterial function, which is beneficial to enhancing the mildew resistance and durability of the strip.

[0021] 2. Since peroxide vulcanizers can decompose to generate free radicals at high temperatures, they can initiate the formation of carbon-carbon cross-links between EPDM rubber molecular chains. Compared with the polysulfide bonds formed by traditional sulfur vulcanization systems, carbon-carbon bonds have higher bond energy and stronger thermal stability, which is beneficial to improving the heat resistance and aging resistance of the rubber strips. The cross-linked network is not easily broken under high temperature or long-term use, which leads to performance degradation. At the same time, peroxide vulcanizers have high reaction activity and can form a uniform and dense cross-linked network in EPDM rubber.

[0022] 3. Since 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and dilauroyl peroxide can generate carbon-carbon cross-linked bonds through free radical reactions, the bond energy is significantly higher than the polysulfide bonds of traditional sulfur vulcanization, and the uniform cross-linking rate of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and dilauroyl peroxide makes it difficult for the microporous foaming agent to over-expand, thereby making the microporous structure dense and uniform, maintaining the sealing performance. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with Examples 1 to 7 and Comparative Examples 1 to 2.

[0024] raw material EPDM rubber; Carbon black CAS: 1333-86-4; Silica CAS: 14464-46-1; Zinc oxide CAS: 1314-13-2; Stearic acid CAS: 57-11-4; Paraffin oil, Hebei Oujia Lubricant Co., Ltd.; Polyethylene glycol CAS: 25322-68-3; Magnesium oxide CAS: 1309-48-4; 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane CAS: 78-63-7; Microcellular foaming agent, Zhejiang Shuntai Technology Co., Ltd. ; 3-iodo-2-propynylbutylcarbamate MacLean Reagent Co., Ltd.; anhydrous ethanol CAS: 64-17-5; deionized water CAS: 7732-18-5; nano zinc oxide Beijing Dekedaojin Technology Co., Ltd.; N,N-dimethylformamide Shanghai Aladdin Biochemical Technology Co., Ltd.; 3-aminopropyltriethoxysilane Shanghai Aladdin Biochemical Technology Co., Ltd.; β-cyclodextrin CAS: 7585-39-9; 1,1-carbonyldiimidazole Shanghai Aladdin Biochemical Technology Co., Ltd.

[0025] Example 1 A dense pore sealing strip comprises the following raw materials in parts by mass: 100 parts of EPDM rubber, 75 parts of carbon black, 15 parts of white carbon black, 6.5 parts of zinc oxide, 2 parts of stearic acid, 50 parts of paraffin oil, 0.75 parts of polyethylene glycol, 2.5 parts of magnesium oxide, 4 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1.25 parts of mildew inhibitor, and 4.5 parts of microporous foaming agent.

[0026] Specifically, the preparation method of the dense pore sealing strip includes the following steps: S1: 5 g of nano-zinc oxide was dispersed in 200 ml of N,N-dimethylformamide, stirred for 15 min and ultrasonically vibrated for 1 h, then 6 mL of 3-aminopropyltriethoxysilane was added dropwise, and stirred at 90°C for 6 h. After cooling to 25°C, the mixture was centrifuged at 4000 rpm for 10 min. The separated solid particles were washed with N,N-dimethylformamide and deionized water, and then dried in a vacuum drying oven at 40°C for 3 days and ground to obtain an intermediate product. S2: Weigh 6 g of β-cyclodextrin and dissolve it in 200 mL of N,N-dimethylformamide. Then, add 6 mL of 1,1-carbonyldiimidazole dropwise and stir magnetically at 25°C for 2 h to obtain an activated β-cyclodextrin solution. S3: The intermediate product was dispersed in 200 mL of N,N-dimethylformamide, and the activated β-cyclodextrin solution was slowly added dropwise thereto. The mixture was stirred at 25°C for 20 h, and then washed with N,N-dimethylformamide and deionized water. The mixture was dried in a drying oven at 60°C for 2 days and then ground to obtain modified nano-zinc oxide. S4: Weigh 20 g of 3-iodo-2-propynyl butyl carbamate into a beaker, add 25.35 ml of anhydrous ethanol and 60 ml of deionized water, and stir until the 3-iodo-2-propynyl butyl carbamate is completely dissolved to obtain a mixed solution, weigh 3 g of modified nano-zinc oxide and add it to 30 ml of the mixed solution for ultrasonic dispersion treatment, then put it into a vacuum drying oven, and evacuate the vacuum dryer to -0.09 MPa, blend for 1 hour, let it stand for 30 minutes, then take it out, and then centrifuge it at a speed of 3000 r / min. Finally, dry it in an oven at 30°C for 12 hours to obtain a mildew inhibitor; S5: First, 100 parts of EPDM rubber are pressurized and mixed, and then 75 parts of carbon black, 15 parts of white carbon black, 6.5 parts of zinc oxide, 2 parts of stearic acid, 0.75 parts of polyethylene glycol, and 25 parts of paraffin oil are added in sequence, mixed evenly, and then discharged at a discharge temperature of 150°C, discharged, cooled, and stored; S6: The intermediate obtained in S5 is allowed to stand for 24 hours and then mixed. Then, 2.5 parts of magnesium oxide, 4 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1.25 parts of mildew inhibitor, and 4.5 parts of microporous foaming agent are added and mixed. The discharge temperature is controlled at 90° C. and the roller distance during thin pass is 1.25 mm to obtain a mixed rubber. S7: The rubber compound is extruded from a specific mold in a rubber extruder and placed in molten salt at 265°C, isolated from air for vulcanization; S8: After the reaction is completed, the product is cooled, formed, and welded to the entire frame.

[0027] Example 2-Example 3 The difference from Example 1 is that the added mass fractions of each component of the dense pore sealing strip are different, as shown in Table 1.

[0028] Table 1. Addition of each component of the dense pore sealing strip in Examples 1 to 3 (parts) Example 1 Example 2 Example 3 EPDM 100 90 110 carbon black 75 90 60 Silica 15 10 20 zinc oxide 6.5 5 8 stearic acid 2 3 1 paraffin oil 50 60 40 polyethylene glycol 0.75 0.5 1 magnesium oxide 2.5 2 3 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane 4 5 3 mildew inhibitors 1.25 1 1.5 Microcellular foaming agent 4.5 6 3 Example 4-Example 5 The difference from Example 1 is that the addition amount of each component of the mildew inhibitor is different, as shown in Table 2.

[0029] Table 2 Addition amount of each component of the mildew inhibitor in Example 1 and Example 4-Example 5 Example 1 Example 4 Example 5 Modified nano zinc oxide 3g 1g 5g 3-Iodo-2-propynylbutylcarbamate 20g 25g 15g Anhydrous ethanol 25.35ml 25ml 25.7ml Deionized water 60ml 65ml 55ml Example 6-Example 7 The difference from Example 1 is that the addition amount of each component of the modified nano zinc oxide is different, as shown in Table 3.

[0030] Table 3 Addition amount of each component of modified nano zinc oxide in Example 1 and Example 6-Example 7 Example 1 Example 6 Example 7 Nano zinc oxide 5g 3g 7g N,N-dimethylformamide 600ml 490ml 710ml 3-Aminopropyltriethoxysilane 6ml 9ml 3ml β-cyclodextrin 6g 7g 5g 1,1-Carbonyldiimidazole 6ml 5ml 7ml Comparative Example 1 The difference from Example 1 is that 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is replaced with an equal amount of the vulcanization system; Among them, the vulcanization system consists of sulfur powder and accelerator NR.

[0031] Comparative Example 2 The difference from Example 1 is that no mildew inhibitor is added.

[0032] Performance testing 1. Sealing performance Three samples were taken from each of Examples 1 to 7 and Comparative Examples 1 to 2. Twenty-seven identical glass bottles with a diameter of 3 cm and a height of 5 cm were taken, and each sample was made into a sealing ring pattern that matched the glass bottle cap. The 27 sealing ring samples were installed in the bottle cap, and the interior of the glass bottle was kept dry. White copper sulfate powder was poured into the 27 glass bottles, and then the 27 bottle caps were respectively used to cover the glass bottles. The 27 glass bottles were then immersed in water. After standing for 1 hour, the glass bottles were fished out and the color of the copper sulfate powder in the glass bottles was observed and recorded. The test data is shown in Table 4.

[0033] Table 4 Sealing performance test results of Examples 1 to 7 and Comparative Examples 1 to 2 Powder color before testing Powder color after testing Example 1 White White Example 2 White White Example 3 White White Example 4 White White Example 5 White White Example 6 White White Example 7 White White Comparative Example 1 White The powder at the bottle mouth is darker blue, and the powder inside is light blue Comparative Example 2 White White 2. Mechanical properties Three samples were taken from each of Examples 1 to 7 and Comparative Examples 1 and 2, and the tensile strength and elongation at break of the samples were tested according to GB / T 528-2009 "Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties"; The test data is shown in Table 5.

[0034] Table 5 Mechanical properties test results of Examples 1 to 7 and Comparative Examples 1 to 2 Tensile strength (MPa) Elongation at break (%) Example 1 4.44 197 Example 2 4.12 185 Example 3 4.08 190 Example 4 4.20 192 Example 5 4.15 188 Example 6 4.25 195 Example 7 4.18 193 Comparative Example 1 3.25 142 Comparative Example 2 4.31 187 3. Anti-mildew performance Three samples were taken from each of Examples 1 to 7 and Comparative Examples 1 to 2, and the anti-mildew properties of the samples were tested according to JC / T 885-2001 "Anti-mildew sealants for construction"; Anti-mildew grade description: Level 0: No obvious mold growth under 50x magnification; Level 1: The mold is invisible or difficult to see with the naked eye, but can be clearly seen under a magnifying glass; Level 2: Mold is clearly visible to the naked eye, with a coverage rate of 10% to 30% on the sample surface; Level 3: Mold is clearly visible to the naked eye, with a coverage rate of 30% to 60% on the sample surface; Level 4: Mold is clearly visible to the naked eye, with a coverage rate greater than 60% on the sample surface; The test data is shown in Table 6.

[0035] Table 6 Anti-mildew performance test results of Examples 1 to 7 and Comparative Examples 1 to 2 Mildew resistance (grade) Example 1 0 Example 2 0 Example 3 0 Example 4 0 Example 5 0 Example 6 0 Example 7 0 Comparative Example 1 0 Comparative Example 2 3 Combining Example 1 and Comparative Example 1 and Tables 4 to 6, it can be seen that compared with Example 1, the mildew resistance of Comparative Example 1 is still at level 0, but after testing, the powder at the bottle mouth of Comparative Example 1 is darker blue, and the internal powder is light blue. At the same time, the tensile strength and elongation at break of Comparative Example 1 are significantly reduced. This shows that compared with the addition of a conventional vulcanization system, the addition of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane can effectively improve the mechanical properties of the sealing strip and is not likely to affect the sealing performance and mildew resistance of the sealing strip.

[0036] Combining Example 1 and Comparative Example 2 and Tables 4 to 6, it can be seen that, compared with Example 1, the color of the powder of Comparative Example 2 is still white after testing, the tensile strength and elongation at break of Comparative Example 2 are reduced, and the mildew resistance of Comparative Example 2 is at level 3. This shows that, compared with not adding a mildew inhibitor, adding a mildew inhibitor can effectively improve the mildew resistance of the sealing strip, and the mildew inhibitor is not easy to affect the sealing performance and mechanical properties of the sealing strip.

[0037] Combining Example 1 and Example 2-Example 3 and Table 4-Table 6, it can be seen that, compared with Example 1, the color of the powder of Example 2 and Example 3 after testing is still white, and the mildew resistance of Example 2 and Example 3 is still at level 0. At the same time, the tensile strength and elongation at break of Example 2 and Example 3 are reduced. This shows that the mass fraction of each component added to the dense pore sealing strip affects the mechanical properties of the sealing strip. Therefore, the mass fraction of each component added to the dense pore sealing strip in Example 1 can effectively improve the mechanical properties of the sealing strip without affecting the sealing performance and mildew resistance of the sealing strip.

[0038] Combining Example 1 and Example 4-Example 5 and Table 4-Table 6, it can be seen that, compared with Example 1, the color of the powder of Example 4 and Example 5 after testing is still white, and the mildew resistance of Example 4 and Example 5 is still at level 0. At the same time, the tensile strength and elongation at break of Example 4 and Example 5 are reduced. This shows that the addition amount of each component of the mildew inhibitor affects the mechanical properties of the sealing strip. Therefore, the addition amount of each component of the mildew inhibitor in Example 1 can effectively improve the mechanical properties of the sealing strip without affecting the sealing performance and mildew resistance of the sealing strip.

[0039] Combining Example 1 and Example 6-Example 7 and Table 4-Table 6, it can be seen that, compared with Example 1, the color of the powder of Example 6 and Example 7 after testing is still white, and the mildew resistance of Example 6 and Example 7 is still at level 0. At the same time, the tensile strength and elongation at break of Example 6 and Example 7 are reduced. This shows that the addition amount of each component of the modified nano-zinc oxide affects the mechanical properties of the sealing strip. Therefore, the addition amount of each component of the modified nano-zinc oxide in Example 1 can effectively improve the mechanical properties of the sealing strip without affecting the sealing performance and mildew resistance of the sealing strip.

[0040] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A dense pore sealing strip, characterized in that: The invention comprises the following raw materials in parts by weight: 90-110 parts of EPDM rubber, 60-90 parts of carbon black, 10-20 parts of white carbon black, 5-8 parts of zinc oxide, 1-3 parts of stearic acid, 40-60 parts of paraffin oil, 0.5-1 part of polyethylene glycol, 2-3 parts of magnesium oxide, 3-5 parts of vulcanization system, 1-1.5 parts of mildew inhibitor, and 3-6 parts of microporous foaming agent.

2. The dense pore sealing strip according to claim 1, characterized in that: The vulcanization system is a peroxide vulcanizing agent, and the peroxide vulcanizing agent is one of alkyl peroxide and diacyl peroxide.

3. The dense pore sealing strip according to claim 2, characterized in that: The peroxide curing agent is one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and dilauroyl peroxide.

4. The dense pore sealing strip according to claim 1, characterized in that: The paraffin oil has a flash point of above 280° C. and an aromatic hydrocarbon content of 0%.

5. The dense pore sealing strip according to claim 1, characterized in that: The mildew inhibitor comprises the following raw materials: 1-5g modified nano zinc oxide, 15-25g 3-iodo-2-propynyl butyl carbamate, 25-25.7ml anhydrous ethanol, 55-65ml deionized water.

6. The dense pore sealing strip according to claim 5, characterized in that: The preparation method of the mildew inhibitor comprises the following steps: weighing 15-25 g of 3-iodo-2-propynyl butyl carbamate into a beaker, adding 25-25.7 ml of anhydrous ethanol and 55-65 ml of deionized water, stirring until the 3-iodo-2-propynyl butyl carbamate is completely dissolved to obtain a mixed solution, weighing 1-5 g of modified nano zinc oxide into 10-50 ml of the mixed solution, performing ultrasonic dispersion treatment, then placing the mixture into a vacuum drying oven, evacuating the vacuum dryer to -0.06 to -0.12 MPa, mixing for 0.5-1.5 hours, standing for 25-35 minutes, taking the mixture out, then centrifuging at a speed of 2500-3500 r / min, and finally drying the mixture in an oven at 25-35° C. for 10-14 hours to obtain the mildew inhibitor.

7. The dense pore sealing strip according to claim 6, characterized in that: The modified nano zinc oxide comprises the following raw materials: 3-7g nano zinc oxide, 490-710ml N,N-dimethylformamide, 3-9mL 3-aminopropyltriethoxysilane, 5-7g β-cyclodextrin, 5-7mL 1,1-carbonyldiimidazole.

8. The dense pore sealing strip according to claim 7, characterized in that: The preparation method of the modified nano zinc oxide comprises the following steps: weighing 3-7 g of nano zinc oxide, dispersing the nano zinc oxide in 150-250 ml of N, N-dimethylformamide, stirring for 10-20 minutes and ultrasonically oscillating for 0.5-1.5 hours, then dropwise adding 3-9 ml of 3-aminopropyltriethoxysilane, stirring at 85-95° C. for 5-7 hours, cooling to 20-30° C., centrifuging at 3500-4500 r / min for 8-12 minutes, washing the separated solid particles with N, N-dimethylformamide and deionized water, and then drying the solid particles in a vacuum drying oven at 35-45° C. for 2-4 days and grinding the solid particles to obtain an intermediate product; weighing 5-7 g of β-cyclodextrin, dissolving the nano zinc oxide in 180-220 ml of N, N-dimethylformamide, and then dropwise adding 5-7 ml of 1,1-carbonyldiimidazole is magnetically stirred at 20-30°C for 1-3 hours to obtain an activated β-cyclodextrin solution; the intermediate product is dispersed in 160-240 mL of N,N-dimethylformamide, the activated β-cyclodextrin solution is slowly added dropwise thereto, and the mixture is stirred at 20-30°C for 15-25 hours, and washed with N,N-dimethylformamide and deionized water. The mixture is placed in a drying oven and dried at 55-65°C for 1-3 days, and then ground to obtain modified nano-zinc oxide.

9. The method for preparing a dense pore sealing strip according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: First, after pressurizing and kneading 90-110 parts of EPDM rubber, 60-90 parts of carbon black, 10-20 parts of white carbon black, 5-8 parts of zinc oxide, 1-3 parts of stearic acid, 0.5-1 part of polyethylene glycol, and 20-30 parts of paraffin oil are added in sequence, kneaded evenly, and then discharged at a discharge temperature of 145-155°C. The product is discharged, cooled, and stored to obtain an intermediate; S2: The intermediate obtained in S1 is allowed to stand for 22-26 hours and then mixed. Then, 2-3 parts of magnesium oxide, 3-5 parts of vulcanization system, 1-1.5 parts of mildew inhibitor, and 3-6 parts of microporous foaming agent are added and mixed. The discharge temperature is controlled at 80-100°C, and the roller distance during thin pass is 1-1.5mm to obtain a mixed rubber. S3: The rubber compound is extruded from a specific mold in a rubber extruder and placed in molten salt at 250-280°C, isolated from air for vulcanization; S4: After the reaction is completed, the product is cooled, formed, and welded to the entire frame.