Water swelling sealing rod for waterproof sealing and preparation method of water swelling sealing rod
By inducing the copolymerization of acrylonitrile and vinylpyridine monomers on the surface of the aramid fiber, the modified aramid fiber is prepared, which solves the problem of poor binding force between the water-absorbing resin and the rubber, and improves the water-absorbing expansion rate and mechanical properties of the rubber.
Patent Information
- Application Number
- CN202510597779.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-09
- Publication Date
- 2025-08-08
AI Technical Summary
The bonding force between the water-absorbing resin and rubber in the existing water-expanded water-stop strip is poor, which causes the water-absorbing resin to easily separate and fall off during the use of the water-absorbing expansion rubber, affecting the performance of the use.
By initiating the copolymerization of acrylonitrile and vinylpyridine monomers on the surface of the aramid fiber, P(AN)-co-P(4-VP) grafted modified aramid fibers are formed, increasing its contact area with rubber and water-absorbing resin, and improving adhesion through mechanical interlocking, while introducing 4-VP to enhance the hydrophilicity of the aramid fibers.
It improves the adhesion of the water-absorbing expansion rubber, reduces the separation and fall of the water-absorbing resin, and improves the water-absorbing expansion rate and mechanical properties of the rubber.
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Figure BDA0005395082130000071
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of rubber expansion waterstop strips, and particularly relates to a water-expanding waterstop strip for waterproof sealing and a preparation method thereof. Background Art
[0002] Water-swelling waterstop is a unique new rubber product, mainly made of a thorough mixture of polyacrylic acid (such as sodium acrylate cross-linked polymer) water-absorbing resin and base glue. When the joint or construction joint shifts, causing the gap to exceed the elastic range of the material, this type of rubber will expand and deform by 2-3 times after coming into contact with water, and fill all irregular surfaces, cavities and gaps in the joint, while generating huge contact pressure to completely prevent leakage.
[0003] Water-swelling rubber, used as a leak-proof, sealing material, not only saves on usage but also eliminates the elastic fatigue that can occur with conventional elastic materials due to excessive compression, resulting in a more reliable waterproofing effect. However, polyacrylic acid-based water-absorbing resins and rubbers are essentially chemically uncrosslinked; physical compatibilizers are typically used to enhance their compatibility. During use, water-swelling rubber can experience separation and shedding, precipitating on the rubber surface and significantly reducing its performance. Summary of the Invention
[0004] In order to solve the problem of poor bonding strength between water-absorbing resin and rubber in the background art, the present invention provides a water-swelling waterstop strip for waterproof sealing and a preparation method thereof.
[0005] The purpose of the present invention can be achieved through the following technical solutions:
[0006] A water-swelling waterstop for waterproof sealing, comprising, by weight, 50-70 parts of chloroprene rubber, 40-60 parts of water-absorbing resin, 20-30 parts of engine oil, 10-20 parts of carbon black, 0.5-1.5 parts of stearic acid, 4-6 parts of nano zinc oxide, 3-5 parts of modified aramid fiber, 2-3 parts of vulcanizing agent, and 1-2 parts of antioxidant;
[0007] The modified aramid fiber is prepared by the following method:
[0008] The aramid fibers were washed and dried, dissolved in cyclohexane with acrylonitrile and vinyl pyridine, placed in a glass bottle, sealed under nitrogen atmosphere, and exposed to 60 The modified aramid fiber was obtained by radiation copolymerization under a Co point source radiator, ultrasonic cleaning and vacuum drying.
[0009] Furthermore, the water-absorbing resin is sodium polyacrylate.
[0010] Furthermore, the vulcanizing agent is any one or more of 1,2-ethylenethiourea, sulfur and dicumyl peroxide.
[0011] Furthermore, the antioxidant is any one or more of antioxidant 4010NA, antioxidant ZMMBI and antioxidant NBC.
[0012] Furthermore, the engine oil is No. 32 engine oil, and the length of the aramid fiber is 6 mm.
[0013] Furthermore, the usage ratio of the aramid fiber, acrylonitrile, vinyl pyridine and cyclohexane is 1-2 g: 0.4-1.62 g: 0.02-0.08 g: 50 mL.
[0014] Furthermore, the radiation dose is 4×10 5 Gy, with a dose rate of 6 × 10 3 Gy / h, the radiation temperature is room temperature.
[0015] A method for preparing a water-swellable waterstop strip for waterproof sealing, comprising the following steps:
[0016] After the chloroprene rubber is plasticized at 90°C for 3 minutes, stearic acid, nano zinc oxide, vulcanizing agent, and antioxidant are added in sequence and mixed at 90°C for 3 minutes. Then, the water-absorbing resin and modified aramid fiber are added and mixed at 90°C for 5 minutes. Then, carbon black is added to the mixed rubber material and mixed at 90°C for 8 minutes to obtain a rubber mixture. The rubber mixture is extruded into shape and vulcanized in a microwave-heated vulcanization box to obtain a waterproof and sealed water-swelling waterstop strip.
[0017] Furthermore, the extrusion process parameters are: extrusion temperature 65° C., screw speed 13 r / min, and side pressure roller speed 8 r / min.
[0018] Furthermore, the process parameters of the microwave heating vulcanization box are: microwave power 1000W, microwave section oven temperature 180°C, other three section oven temperatures 170°C, and pulling speed 8m / min.
[0019] Beneficial effects of the present invention:
[0020] The present invention uses gamma ray irradiation to initiate polymerization of acrylonitrile and vinyl pyridine monomers on the surface of aramid fibers. The energy in the gamma rays is transferred to the aramid fibers, inducing the generation of ion pairs and excited molecules in the aramid fibers, generating free radicals. The free radicals generated on the surface of the aramid fibers can react with the acrylonitrile and vinyl pyridine monomers to initiate free radical polymerization. Simultaneously, this process can induce copolymerization between the acrylonitrile and vinyl pyridine monomers to obtain aramid fibers grafted with P(AN), P(4-VP), and P(AN-co-4-VP). The chemically bonded grafting method ensures tight adhesion between the polymer and the aramid fibers. After polymer grafting, the surface of the aramid fibers becomes rougher, increasing the contact area between the aramid fibers, the rubber, and the water-absorbing resin, which is beneficial for stress transfer. Mechanical interlocking increases the adhesion between the rubber and the water-absorbing resin, solving the problem of "separation and shedding" of the water-absorbing resin during use of the water-swelling rubber. In addition, 4-VP, as a hydrophilic monomer, has nitrogen atoms on its pyridine ring that can form hydrogen bonds with water molecules, enhancing the hydrophilicity of the aramid fibers. DETAILED DESCRIPTION
[0021] 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 embodiments described 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 making any creative efforts shall fall within the scope of protection of the present invention.
[0022] Example 1
[0023] A method for preparing a water-swellable waterstop strip for waterproof sealing, comprising the following steps:
[0024] In the first step, 1.5 g of aramid fiber with a length of 6 mm was washed with acetone in a Soxhlet extractor at 70 ° C for 24 h, dried in a vacuum oven at 70 ° C for 3 h, dissolved in 50 mL of cyclohexane with 1 g of acrylonitrile and 0.05 g of vinyl pyridine, and placed in a 100 mL glass bottle with a silica gel cap, sealed under a nitrogen atmosphere, and exposed to 60 Radiation copolymerization was carried out under a Co point source radiator to obtain P(AN), P(4-VP) and P(AN-co-4-VP) grafted aramid fibers. The fibers were then washed with acetone for 15 min in an ultrasonic cleaner to remove physically absorbed acrylonitrile and vinyl pyridine. The fibers were then washed with deionized water for 5 min and dried in a vacuum oven at -0.1 MPa and 70°C for 10 h to obtain modified aramid fibers. The radiation dose at room temperature was 4×10 5 Gy, with a dose rate of 6 × 10 3 Gy / h.
[0025] The second step is to place 25g of chloroprene rubber on a SK160B double-roller mill, and after plasticating at 90℃ for 3 minutes, add 0.25g of stearic acid, 2g of nano zinc oxide, 1g of 1,2-ethylene thiourea, 0.5g of antioxidant 4010NA and 10g of No. 32 engine oil, mix at 90℃ for 3 minutes, continue to add 20g sodium polyacrylate and 1.5g modified aramid fiber, mix at 90℃ for 5 minutes, then add 5g carbon black to the mixed rubber material, mix at 90℃ for 8 minutes to obtain a rubber compound, extrudate the rubber compound, and vulcanize it in a microwave heating vulcanization box to obtain a waterproof and sealed water-swelling waterstop strip. The extrusion process parameters are: extrusion temperature 65℃, screw speed 13r / min, side pressure roller speed 8r / min, and microwave heating vulcanization box process parameters are: microwave power 1000W, microwave section oven temperature 180℃, other three section oven temperatures 170℃, and traction speed 8m / min.
[0026] Example 2
[0027] A method for preparing a water-swellable waterstop strip for waterproof sealing, comprising the following steps:
[0028] In the first step, 1 g of 6 mm long aramid fiber was washed with acetone in a Soxhlet extractor at 70 °C for 24 h, dried in a vacuum oven at 70 °C for 3 h, dissolved in 50 mL of cyclohexane with 0.4 g of acrylonitrile and 0.02 g of vinyl pyridine, and placed in a 100 mL glass bottle with a silica gel cap, sealed under a nitrogen atmosphere, and exposed to 60 Radiation copolymerization was carried out under a Co point source radiator to obtain P(AN), P(4-VP) and P(AN-co-4-VP) grafted aramid fibers. The fibers were then washed with acetone for 15 min in an ultrasonic cleaner to remove physically absorbed acrylonitrile and vinyl pyridine. The fibers were then washed with deionized water for 5 min and dried in a vacuum oven at -0.1 MPa and 70°C for 10 h to obtain modified aramid fibers. The radiation dose at room temperature was 4×10 5 Gy, with a dose rate of 6 × 10 3 Gy / h.
[0029] The second step is to place 15g of chloroprene rubber on a SK160B double-roller mill, and after plasticating at 90℃ for 3 minutes, add 0.25g of stearic acid, 1.25g of nano zinc oxide, 0.625g of sulfur, 0.375g of antioxidant ZMMBI and 6.25g of No. 32 engine oil, mix at 90℃ for 3min, continue to add 12.5g sodium polyacrylate and 1g modified aramid fiber, mix at 90℃ for 5min, then add 3.75g carbon black to the mixed rubber material, mix at 90℃ for 8min to obtain a rubber compound, extrudate the rubber compound, and vulcanize it in a microwave heating vulcanization box to obtain a waterproof and sealed water-swelling waterstop strip. The extrusion process parameters are: extrusion temperature 65℃, screw speed 13r / min, side pressure roller speed 8r / min, microwave heating vulcanization box process parameters are: microwave power 1000W, microwave section oven temperature 180℃, other three section oven temperature 170℃, and traction speed 8m / min.
[0030] Example 3
[0031] A method for preparing a water-swellable waterstop strip for waterproof sealing, comprising the following steps:
[0032] In the first step, 2 g of 6 mm long aramid fiber was washed with acetone in a Soxhlet extractor at 70 °C for 24 h, dried in a vacuum oven at 70 °C for 3 h, dissolved in 50 mL of cyclohexane with 1.62 g of acrylonitrile and 0.08 g of vinyl pyridine, and placed in a 100 mL glass bottle with a silica gel cap, sealed under a nitrogen atmosphere, and exposed to 60 Radiation copolymerization was carried out under a Co point source radiator to obtain P(AN), P(4-VP) and P(AN-co-4-VP) grafted aramid fibers. The fibers were then washed with acetone for 15 min in an ultrasonic cleaner to remove physically absorbed acrylonitrile and vinyl pyridine. The fibers were then washed with deionized water for 5 min and dried in a vacuum oven at -0.1 MPa and 70°C for 10 h to obtain modified aramid fibers. The radiation dose at room temperature was 4×10 5 Gy, with a dose rate of 6 × 10 3 Gy / h.
[0033] The second step is to place 28g of chloroprene rubber on a SK160B double-roller mill, and after plasticating at 90℃ for 3 minutes, add 0.6g of stearic acid, 2.4g of nano zinc oxide, 1.2g of dicumyl peroxide, 0.8g of antioxidant NBC and 12g of No. 32 engine oil, mix at 90℃ for 3 minutes, continue to add 24g sodium polyacrylate and 2g modified aramid fiber, mix at 90℃ for 5 minutes, then add 8g carbon black to the mixed rubber material, mix at 90℃ for 8 minutes to obtain a rubber compound, extrudate the rubber compound, and vulcanize it in a microwave heating vulcanization box to obtain a waterproof and sealed water-swelling waterstop strip. The extrusion process parameters are: extrusion temperature 65℃, screw speed 13r / min, side pressure roller speed 8r / min, microwave heating vulcanization box process parameters are: microwave power 1000W, microwave section oven temperature 180℃, other three section oven temperatures 170℃, and traction speed 8m / min.
[0034] Comparative Example 1
[0035] A method for preparing a water-swelling waterstop strip for waterproof sealing, which differs from Example 3 in that the first step is removed and the "modified aramid fiber" in the second step is replaced by "aramid fiber". The remaining raw materials and preparation process are the same as Example 3.
[0036] Comparative Example 2
[0037] A method for preparing a water-swelling waterstop strip for waterproof sealing, which differs from Example 3 in that "1.62g acrylonitrile" in the first step is removed, and the remaining raw materials and preparation process are the same as Example 3.
[0038] Comparative Example 3
[0039] A method for preparing a water-swelling waterstop strip for waterproof sealing, which differs from Example 3 in that "0.08g vinyl pyridine" is removed in the first step, and the remaining raw materials and preparation process are the same as Example 3.
[0040] The performance tests of the waterproof and sealed water-swellable waterstop strips obtained in Examples 1-3 and Comparative Examples 1-3 were carried out, and the test items were as follows:
[0041] 1. Mass loss rate experiment
[0042] The waterproof and sealed water-swellable waterstop obtained in the example was cut into 30 mm × 10 mm × 10 mm samples, and the mass before immersion was measured. The samples were then immersed in tap water until they were saturated with water, and then dried at 50° C. to constant weight. The weight loss rate was measured and calculated according to the following formula:
[0043] △M(%)=(M0-M1) / M0×100%
[0044] Where: △M—weight loss rate of waterstop;
[0045] M0—the quality of the waterstop before immersion in water;
[0046] M1—The mass of the waterstop after absorbing water and drying. The test results are shown in Table 1.
[0047] Table 1
[0048] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Weight loss rate% 6.8 6.3 5.9 20.8 16.4 13.7
[0049] It can be seen from Table 1 that the weight loss rate of the waterproof and sealed water-swelling waterstop strip obtained by adding the modified aramid fiber prepared by the present invention is significantly reduced. This is because the introduction of the modified aramid fiber with a rough surface increases the adhesion between the rubber and the water-absorbing resin through mechanical interlocking.
[0050] 2. Water absorption expansion rate and mechanical properties test
[0051] Shore A hardness, maximum water swelling rate, tensile strength, and elongation at break were determined according to the method specified in GB / T 18173.3-2014, a standard for water-swellable rubber. The repeated water immersion test procedure involved immersing the specimen in distilled water at room temperature for 12 h, removing it from the water, drying it at 70°C for 8 h, then immersing it in water for another 12 h, and then drying it for another 8 h. After four cycles of repeated immersion and drying, the tensile strength and elongation at break were measured. The test results are shown in Table 2.
[0052] Table 2
[0053]
[0054] It can be seen from Table 2 that the Shore A hardness has little effect on whether the aramid fiber is modified. After adding the modified aramid fiber prepared by the present invention, the maximum volume expansion rate of the water-swelling waterstop is significantly improved compared with the unmodified aramid fiber. In addition, the surface of the unmodified aramid fiber is relatively smooth, and the adhesion to rubber is poor. The strains generated by aramid and rubber in response to stress are different. Under the action of stress, defects will be generated at the interface between the aramid fiber and the rubber, resulting in a decrease in the tensile strength and elongation at break of the water-swelling waterstop.
[0055] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.
[0056] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A water-swellable waterstop strip for waterproof sealing, characterized in that: The composition comprises, by weight, 50-70 parts of chloroprene rubber, 40-60 parts of water-absorbing resin, 20-30 parts of engine oil, 10-20 parts of carbon black, 0.5-1.5 parts of stearic acid, 4-6 parts of nano zinc oxide, 3-5 parts of modified aramid fiber, 2-3 parts of vulcanizing agent, and 1-2 parts of antioxidant; The modified aramid fiber is prepared by the following method: The aramid fiber was washed and dried, and then acrylonitrile and vinyl pyridine were added to cyclohexane and placed in a glass bottle, which was sealed under nitrogen atmosphere and exposed to 60 The modified aramid fiber was obtained by radiation copolymerization under a Co point source radiator, ultrasonic cleaning and vacuum drying.
2. The water-swellable waterstop strip for waterproof sealing according to claim 1, characterized in that: The water-absorbing resin is sodium polyacrylate.
3. The water-swellable waterstop strip for waterproof sealing according to claim 1, characterized in that: The vulcanizing agent is any one or more of 1,2-ethylenethiourea, sulfur and dicumyl peroxide.
4. The water-swellable waterstop strip for waterproof sealing according to claim 1, characterized in that: The antioxidant is any one or more of antioxidant 4010NA, antioxidant ZMMBI and antioxidant NBC.
5. The water-swellable waterstop strip for waterproof sealing according to claim 1, characterized in that: The engine oil is No. 32 engine oil and the aramid fiber length is 6 mm.
6. The water-swellable waterstop strip for waterproof sealing according to claim 1, characterized in that: The usage ratio of aramid fiber, acrylonitrile, vinyl pyridine and cyclohexane is 1-2g: 0.4-1.62g: 0.02-0.08g: 50mL.
7. The water-swellable waterstop strip for waterproof sealing according to claim 1, characterized in that: The radiation dose was 4×10 5 Gy, with a dose rate of 6 × 10 3 Gy / h, the radiation temperature is room temperature.
8. A method for preparing a water-swellable waterstop strip for waterproof sealing as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: After plasticizing the chloroprene rubber at 90°C for 3 minutes, stearic acid, nano zinc oxide, vulcanizing agent, antioxidant and engine oil are added in sequence and mixed at 90°C for 3 minutes. Then, water-absorbing resin and modified aramid fiber are added and mixed at 90°C for 5 minutes. Then, carbon black is added to the mixed rubber material and mixed at 90°C for 8 minutes to obtain a rubber mixture. The rubber mixture is extruded into shape and vulcanized in a microwave-heated vulcanization box to obtain a waterproof and sealed water-swelling waterstop strip.
9. The method for preparing a water-swellable waterstop strip for waterproof sealing according to claim 8, characterized in that: The extrusion process parameters are: extrusion temperature 65°C, screw speed 13 r / min, and side pressure roller speed 8 r / min.
10. The method for preparing a water-swellable waterstop strip for waterproof sealing according to claim 8, characterized in that: The process parameters of the microwave heating vulcanization box are: microwave power 1000W, microwave section oven temperature 180℃, other three sections oven temperature 170℃, pulling speed 8m / min.