Anti-aging water-stop belt as well as preparation method and application thereof

Abstract

The invention discloses an anti-aging water-stop belt and a preparation method and application thereof, and relates to the technical field of water-stop belts. The invention relates to an anti-aging water-stop belt which is prepared from the following raw materials in parts by mass: 40-60 parts of chloroprene rubber, 10-20 parts of natural rubber, 10-20 parts of ethylene propylene diene monomer, 15-30 parts of carbon black, 5-15 parts of white carbon black, 5-15 parts of a plasticizer, 0.5-2 parts of sulfur, 0.5-1.5 parts of an accelerant, 1-2 parts of an anti-aging ultraviolet light absorber, 5-15 parts of aluminum hydroxide, 1-3 parts of stearic acid and 3-8 parts of zinc oxide. The obtained water-stop belt has excellent ultraviolet aging resistance, ozone resistance and chemical corrosion resistance while keeping high elasticity, the mechanical stability of the water-stop belt is remarkably improved compared with that of a traditional product, the water-stop belt is suitable for joint sealing in harsh environments such as bridges, tunnels and water conservancy projects, and the waterproof service life of engineering structures can be effectively prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of waterstops, and particularly to an anti-aging waterstop and its preparation method and application. Background Art

[0002] In the field of modern civil engineering, waterstops play a crucial role in structures such as bridge expansion joints, tunnel joints, and deformation joints in water conservancy projects. By blocking the penetration of moisture, they ensure the structural stability and service durability of buildings, and are the first line of defense against leakage problems.

[0003] However, existing waterstop products have many limitations in practical applications. Traditional waterstops are usually based on a single rubber material, such as natural rubber or neoprene. Although such materials have certain elasticity, their performance will be greatly reduced in the face of complex and changing environmental conditions during long-term use. Long-term exposure to ultraviolet light is a key issue, which can trigger photochemical reactions of rubber molecules, resulting in surface cracking, hardening of the material, and ultimately loss of elasticity.

[0004] In addition, the oxidation effect cannot be ignored. Oxygen molecules in the air will gradually penetrate into the rubber interior, react with the unsaturated bonds in the rubber to form peroxides, and then damage the polymer structure of the rubber. This oxidation aging process will continuously reduce the tensile strength of the waterstop. Especially in some tunnel joints with good ventilation but lack of protection, the tensile strength of the waterstop may decrease within a few years, leading to potential leakage hazards.

[0005] At the same time, the chemical corrosion resistance of existing waterstops also needs to be improved. In some industrial water or acid-base environments, such as the flood discharge tunnels of certain water conservancy projects, the water body may contain corrosive chemical substances, which will react with the waterstop material, damage its surface and internal structure, and shorten the service life of the waterstop.

[0006] These problems highlight the urgent need to develop a waterstop with excellent anti-aging performance to adapt to complex and changing engineering environments and ensure the long-term waterproof safety of buildings. Summary of the Invention

[0007] The object of the present invention is to provide a waterstop with excellent anti-aging performance, anti-ultraviolet, anti-oxidation, and chemical corrosion resistance to meet the requirements of long-term stable waterproofing in complex environments in view of the problems existing in the prior art.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows: An anti-aging waterstop belt is made of the following raw materials in parts by mass: 40-60 parts of chloroprene rubber, 10-20 parts of natural rubber, 10-20 parts of ethylene propylene diene monomer rubber, 15-30 parts of carbon black, 5-15 parts of white carbon black, 5-15 parts of plasticizer, 0.5-2 parts of sulfur, 0.5-1.5 parts of accelerator, 1-2 parts of anti-aging ultraviolet absorber, 5-15 parts of aluminum hydroxide, 1-3 parts of stearic acid, and 3-8 parts of zinc oxide; The anti-aging ultraviolet absorber has the structure shown in Formula 1: Formula 1; Z1 is selected from: O, S, N(R1), C(CH3)2, C(CD3)2; R1 is selected from: H, methyl, tert-butyl, phenyl, deuterated methyl, deuterated tert-butyl, deuterated phenyl.

[0009] Further, the plasticizer is dioctyl phthalate.

[0010] Further, the accelerator is dibenzothiazole disulfide.

[0011] Further, the anti-aging ultraviolet absorber is any one of the compounds shown in the following structures: .

[0012] Further, the synthesis steps of the anti-aging ultraviolet absorber are as follows: ; The first step: Intermediate 1 is synthesized by the Williamson synthesis reaction of Raw material 1 and Raw material 2; The second step: Intermediate 2 is synthesized by boration of Intermediate 1; The third step: The anti-aging ultraviolet absorber is synthesized by the Suzuki coupling reaction of Intermediate 2 and Raw material 3.

[0013] A preparation method of an anti-aging waterstop belt includes the following steps: S1. Mix the chloroprene rubber, natural rubber, and ethylene propylene diene monomer rubber at 80-100 °C for 5-15 min; S2. Add the carbon black, white carbon black, zinc oxide, and stearic acid, and raise the temperature to 110-130 °C and mix for 5-15 min; S3. Cool down to 80-90 °C, add the plasticizer, anti-aging ultraviolet absorber, and aluminum hydroxide, and mix for 5-8 min; S4. The sizing material obtained in S3 is mixed with the sulfur and accelerator, then passed through a calender 3 - 5 times, formed into a sheet, and left standing for 12 - 24 h. S5. The sheet after standing is subjected to vulcanization treatment under the conditions of 150 - 160 °C and 10 - 15 MPa for 20 - 30 min. After cooling, an aging-resistant waterstop is obtained.

[0014] Furthermore, the standing in S4 is carried out under light - shielding conditions.

[0015] Furthermore, after the vulcanization treatment in S5, it also includes heat curing at 50 - 60 °C for 4 - 6 h.

[0016] Furthermore, the cooling process in S5 adopts gradient cooling, and the initial cooling rate is 20 - 30 °C / min.

[0017] Furthermore, the gradient cooling process is divided into three stages: the first stage cools at a rate of 20 - 30 °C / min to 105 - 95 °C, the second stage cools at a rate of 10 - 15 °C / min to 55 - 45 °C, and the third stage cools naturally to room temperature.

[0018] An application of the aging - resistant waterstop in waterstops for bridge expansion joints, tunnel joints or deformation joints in water conservancy projects.

[0019] The molecular structure of the anti - aging ultraviolet absorber described in the present invention has the following characteristics: There is a large π - conjugate system (such as benzotriazole or similar structures) in the molecule, which can absorb ultraviolet rays in the wavelength range of 280 - 400 nm, and convert the ultraviolet energy into heat energy and release it through π→π* electron transition. The selection of the substituent Z1 can adjust the electron cloud distribution of the conjugate system and optimize the absorption wavelength range. Among them, the S atom has a stronger electron - donating ability, which can enhance the absorption of long - wave ultraviolet (UVA). The dissociation energy of the C - D bond is significantly higher than that of the C - H bond, and it is more difficult to break under ultraviolet irradiation. The C - D vibration frequency of the deuterated phenyl is lower than that of the C - H, reducing the matching degree with the ultraviolet photon energy and reducing the occurrence of photodegradation reactions. The N and S heteroatoms in the molecule can act as free - radical scavengers, and the electron - donating groups on the benzene ring can improve the antioxidant activity of the phenolic hydroxyl group, and its antioxidant ability is improved compared with traditional anti - aging agents. The antioxidant mechanism of the phenolic hydroxyl group in the molecule is mainly achieved through two paths: hydrogen atom transfer (HAT) and single - electron transfer (SET). Its O - H bond with a lower bond dissociation energy preferentially provides a hydrogen atom to the free radical to generate a stable phenoxy free radical, which is stabilized by benzene ring conjugation and the electronic effect of the substituent; ultimately, an antioxidant system with both rapid reaction and long - lasting protection is formed.

[0020] The components of the present invention construct a multi-level protection system through synergistic effects: Chloroprene rubber and ethylene propylene diene monomer rubber form an interpenetrating network, and their co-vulcanized cross-linking points improve the ozone resistance by 50% and inhibit stress cracking; carbon black and silica build a two-phase filling system. The former achieves a UV shielding rate of >95%, and the latter releases the anti-aging agent through hydrogen bonding of silanol groups, increasing the tear strength by 40%; aluminum hydroxide decomposes endothermically at 220 °C, cooperating with the gradient cooling process, and finally forming a comprehensive protection system with anti-UV, ozone resistance, flame retardancy and anti-fatigue properties.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Significantly improved aging resistance: By introducing anti-aging UV absorbers and a composite rubber system, a multi-level protection network is formed, effectively inhibiting the degradation of materials caused by ultraviolet rays, ozone and oxidation factors, and extending the service life of the waterstop belt in complex environments.

[0022] 2. Broadened anti-UV absorption range: The optimized large π-conjugated system and heteroatoms in the anti-aging UV absorber molecule act synergistically, enhancing the absorption ability of long-wave ultraviolet rays, achieving UV shielding in a wider wavelength range, and effectively preventing 3. Enhanced antioxidant stability: The active groups in the anti-aging UV absorber significantly reduce the rate of chain oxidation reactions initiated by free radicals through a dual antioxidant mechanism (hydrogen atom transfer and electron transfer), maintaining the long-term stability of the rubber molecular structure.

[0023] 4. Optimization of material mechanical properties: The synergistic reinforcement effect of the composite rubber and the two-phase filler, combined with the gradient vulcanization process, enables the waterstop belt to maintain excellent elastic recovery ability and tear resistance during long-term use, meeting the dynamic deformation requirements of engineering joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the synthesis step of the anti-aging UV absorber described in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative work based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0026] Synthesis Example 1 Synthesis of anti-aging UV absorber 1: ; Step 1: Under nitrogen atmosphere, add 20g of raw material 1, 22.73g of raw material 2, 38.38g of potassium phosphate trihydrate, 0.08g of pyridine-2-carboxylic acid, 0.6g of CuI and 200g of DMSO to the reaction system, heat to 85°C and react for 16h; after cooling, extract the obtained reaction mixture with aqueous ammonia solution and methyl tert-butyl ether, wash the organic phase with water five times, and then wash it twice with saturated NaCl solution; finally, dry the combined organic phase with anhydrous Na2SO4, spin dry, purify with silica gel column, use a mixed solution of petroleum ether and ethyl acetate as eluent, spin dry the solution to obtain 26.98g of intermediate 1. MS [MS+H + ]:504.

[0027] Step 2: Under nitrogen atmosphere, add 26.98g of intermediate 1 and 300g of ultra-dry tetrahydrofuran to the reaction system, cool to -70°C, add 3.63g of n-butyl lithium dropwise, stir for 1h after the addition is complete, add 15.09g of triisopropyl borate dropwise, warm to room temperature naturally after the addition is complete, react for 12h, spin dry, and obtain 19.82g of intermediate 2. MS [MS+H + ]:470.

[0028] Step 3: Under nitrogen atmosphere, add 19.82g of intermediate 2, 24.75g of raw material 3, 1.46g of tetrakis(triphenylphosphine)palladium, 11.67g of potassium carbonate and 200g of a mixed solution of toluene, ethanol and water (volume ratio 2:1:1) into the reaction system, heat to 75°C for reflux reaction for 10 hours, turn off the heating, cool to room temperature, stand for separation, extract the aqueous phase twice with ethyl acetate, combine the organic phases, wash three times with water, spin dry, purify through a silica gel column, use a mixed solution of petroleum ether and ethyl acetate as eluent, spin dry the solution to obtain 28.47g of anti-aging UV absorber 1. MS [MS+H + ]:833.

[0029] Anti-aging UV absorber 1 1 HNMR (deuterated chloroform) δ8.10 (d, 1H), 7.59-7.48 (m, 2H), 7.46-7.39 (m, 2H), 7.27 (s, 1H), 7.17 (ddd, 2H), 7.11-7.02 (m, 2H), 6.90 (d, 1H), 6.68 (dt, 1H), 6.62-6.49 (m, 2H), 6. 46-6.40(m,2H),6.33(s,1H),6.04(s,1H),5.01-4.86(m,2H),4.77(tdd,1H),4.5 1-4.42(m,2H),4.23(dd,1H),3.37-3.27(m,1H),3.13-3.04(m,1H),2.02(d,2H).

[0030] Synthesis Examples 2 - 7 For the anti - aging ultraviolet absorbers synthesized in Synthesis Examples 2 - 7, referring to the synthesis method of Synthesis Example 1, replace raw material 2 therein, and keep the rest unchanged. The specific structures of raw material 2, the anti - aging ultraviolet absorbers, and the MS [MS + H + data are shown in the following table.

[0031]

[0032] Ultraviolet maximum absorption peak test: Prepare the compounds prepared in Synthesis Examples 1 - 7 into a 10 -5 M tetrahydrofuran solution, and measure the ultraviolet maximum absorption peak at 200 - 450 nm.

[0033] DPPH free - radical scavenging experiment: Prepare a 50 μM DPPH test solution with DPPH solid, and the absorbance is 0.45. Preparation of the sample solution: Dissolve the sample (the compounds prepared in Synthesis Examples 1 - 7) with ethanol to prepare a 20 mM solution. Before testing, dilute the 20 mM test compound solution with ethanol to 500 μM, and then dilute it with ethanol to 40 μM for testing. Measurement of A value (test group): In a 96 - well plate, use a pipette to take 40 μL of the ethanol solution of the test compound, and then add 160 μL of the DPPH solution. Measure the A519 nm value at room temperature for 8 h. Measurement of A0 value (blank group): Use a pipette to take 40 μL of ethanol solution, add 160 μL of the DPPH solution, and the measured A value is A0.

[0034] The ultraviolet maximum absorption peaks and DPPH free - radical scavenging rates of the ultraviolet - absorbing antioxidants prepared in Synthesis Examples 1 - 7 are shown in the following table.

[0035]

[0036] Example 1 Preparation of an anti - aging water stop belt, the specific steps are as follows: Raw material ratio (parts by mass): 50 parts of chloroprene rubber, 15 parts of natural rubber, 15 parts of ethylene - propylene - diene monomer rubber, 22 parts of carbon black, 10 parts of white carbon black, 10 parts of dioctyl phthalate (plasticizer), 1.2 parts of sulfur, 1.0 part of dibenzothiazole disulfide (accelerator), 1.5 parts of anti - aging ultraviolet absorber (the compound synthesized in Synthesis Example 1), 10 parts of aluminum hydroxide, 2 parts of stearic acid, 5 parts of zinc oxide.

[0037] Preparation steps: S1. Add chloroprene rubber, natural rubber, and ethylene - propylene - diene monomer rubber into a mixer, and knead at 90 °C for 10 min to form a uniform colloid; S2. Add carbon black, silica, zinc oxide and stearic acid into the internal mixer, heat up to 120 °C, and continue mixing for 10 min; S3. Lower the temperature to 85 °C, add dioctyl phthalate, anti-aging ultraviolet absorber (the compound synthesized in Synthesis Example 1) and aluminum hydroxide, and mix for 6 min; S4. Transfer the rubber compound to the open mill, add sulfur and accelerator, pass it through the mill 4 times thinly, and then calender and form it into a sheet with a thickness of 5 mm. The sheet is left standing in a light-shielded environment for 18 hours; S5. Vulcanization treatment: Place the sheet in a flat vulcanizer and vulcanize it at 155 °C and a pressure of 12 MPa for 25 min. Gradient cooling: The first stage: Cool down to 100 °C at a rate of 25 °C / min; The second stage: Cool down to 50 °C at a rate of 12 °C / min; The third stage: Then cool it to room temperature; Thermal curing: The vulcanized sheet is thermally cured in an oven at 55 °C for 5 hours to further stabilize the crosslinked network, and a weather-resistant waterstop is obtained.

[0038] Examples 2 - 7 For a weather-resistant waterstop prepared in Examples 2 - 7, referring to the preparation method of Example 1, the anti-aging ultraviolet absorber therein is sequentially replaced with the compounds synthesized in Synthesis Examples 2 - 7, and the rest is the same as in Example 1.

[0039] Comparative Example 1 For a weather-resistant waterstop, referring to the preparation method of Example 1, the anti-aging ultraviolet absorber therein is replaced with Comparative Compound 1, and the rest is the same as in Example 1.

[0040] The structure of Comparative Compound 1 is: .

[0041] Comparative Example 3 For a weather-resistant waterstop, referring to the preparation method of Example 1, the anti-aging ultraviolet absorber therein is not added, and the rest is the same as in Example 1.

[0042] Performance test: Anti-ultraviolet aging property: Cut the waterstop belt (a kind of aging-resistant waterstop belt prepared in Examples 1-7 and Comparative Examples 1-3) into dumbbell-shaped specimens of equal size according to the method specified in GB / T9865.1. Conduct the pretreatment experiment according to the experimental method of artificial weathering of vulcanized rubber (fluorescent ultraviolet lamp) in GB / T16585-1996. One cycle consists of 4 hours of light exposure and 4 hours of cooling. After three cycles of light exposure and cooling of the dumbbell-shaped waterstop belt specimens, take them out. The anti-ultraviolet aging performance of the waterstop belt is reflected by the tensile stress-strain performance of the waterstop belt after being irradiated by ultraviolet light. Determine the tensile stress-strain performance of the waterstop belt according to GBT528-1998. Place the dumbbell-shaped waterstop belt specimens evenly on the upper and lower holders of a tensile testing machine moving at a constant speed, conduct stretching, start the testing machine, and conduct detection. The higher the tensile strength, the breaking tensile strength, and the elongation at break, the better the anti-ultraviolet aging performance.

[0043]

[0044] The mechanical properties of the samples in the examples are significantly better than those in the comparative examples, reflecting the synergistic effect of the new antioxidant and the composite rubber system. The tensile strength and elongation at break of the examples are both stably in the upper limit range of the technical indicators. Due to the lack of key structural design in the comparative examples, the performance shows a step-by-step decline. Through the longitudinal comparison between the examples, it can be seen that antioxidants containing specific heteroatoms and conjugated structures (such as Examples 6-7) can effectively inhibit the molecular chain breakage caused by ultraviolet rays during the anti-aging process of the material, and their mechanical retention ability is significantly better than that of the conventional system, verifying the decisive role of structural optimization in the durability of the material.

[0045] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An aging-resistant waterstop, characterized in that, It is made from the following raw materials in parts by mass: 40 - 60 parts of chloroprene rubber, 10 - 20 parts of natural rubber, 10 - 20 parts of ethylene propylene diene monomer rubber, 15 - 30 parts of carbon black, 5 - 15 parts of white carbon black, 5 - 15 parts of plasticizer, 0.5 - 2 parts of sulfur, 0.5 - 1.5 parts of accelerator, 1 - 2 parts of anti-aging ultraviolet absorber, 5 - 15 parts of aluminum hydroxide, 1 - 3 parts of stearic acid, 3 - 8 parts of zinc oxide; The anti-aging ultraviolet absorber has the structure shown in Formula 1: Formula 1; Z1 is selected from: O, S, N(R1), C(CH3)2, C(CD3)2; R1 is selected from: H, methyl, tert-butyl, phenyl, deuterated methyl, deuterated tert-butyl, deuterated phenyl.

2. The weather-resistant water stop belt according to claim 1, characterized in that, The plasticizer is dioctyl phthalate.

3. The anti-aging waterstop according to claim 1, characterized in that, The accelerator is dibenzothiazole disulfide.

4. A weather-resistant waterstop according to claim 1, characterized in that, The anti-aging ultraviolet absorber is any one of the compounds shown in the following structures: 。 5. A preparation method of an anti-aging water stop belt according to any one of claims 1-4, characterized in that, It includes the following steps: S1. Mix the chloroprene rubber, natural rubber, and ethylene propylene diene monomer rubber at 80 - 100 °C for 5 - 15 min; S2. Add the carbon black, white carbon black, zinc oxide, and stearic acid, and raise the temperature to 110 - 130 °C and mix for 5 - 15 min; S3. Cool down to 80 - 90 °C, add the plasticizer, anti-aging ultraviolet absorber, and aluminum hydroxide, and mix for 5 - 8 min; S4. Mix the rubber compound obtained in S3 with the sulfur and accelerator, then thin-pass it 3 - 5 times, form it into a sheet and let it stand for 12 - 24 h; S5. Conduct vulcanization treatment on the sheet after standing. The treatment conditions are to maintain at 150 - 160 °C and 10 - 15 MPa for 20 - 30 min, and after cooling, a weather-resistant water stop belt is obtained.

6. The preparation method of an anti-aging water stop belt according to claim 5, characterized in that, The standing in S4 is carried out under light-shielded conditions.

7. The preparation method of an anti-aging waterstop strip according to claim 5, characterized in that, After the vulcanization treatment in S5, it also includes heat curing at 50 - 60 °C for 4 - 6 h.

8. The preparation method of an anti-aging water stop belt according to claim 5, characterized in that, The cooling process in S5 adopts gradient cooling, and the initial cooling rate is 20 - 30 °C / min.

9. The preparation method of an anti-aging waterstop strip according to claim 8, characterized in that, The gradient cooling process is divided into three stages: the first stage cools at a rate of 20 - 30 °C / min to 105 - 95 °C, the second stage cools at a rate of 10 - 15 °C / min to 55 - 45 °C, and the third stage naturally cools to room temperature.

10. Application of a weather-resistant water stop belt according to any one of claims 1 - 4 in water stopping at bridge expansion joints, tunnel joints or deformation joints of water conservancy projects.

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