Aging-resistant waterstop and preparation method and application thereof

Abstract

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

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waterstop, in particular to a kind of anti-aging waterstop and its preparation method and application. BACKGROUND

[0002] In the field of modern civil engineering, whether it is bridge expansion joint, tunnel joint or water conservancy deformation joint structure, waterstop plays a crucial role. It blocks water penetration to ensure the structural stability and durability of buildings, and is the first line of defense against leakage problems.

[0003] However, existing waterstop products have many limitations in practical application. Traditional waterstop is usually based on 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 environmental conditions during long-term use. Long-term exposure to ultraviolet light is a key problem, which can cause photochemical reactions of rubber molecules, leading to surface cracking, hardening and ultimately loss of elasticity.

[0004] In addition, oxidation cannot be ignored. Oxygen molecules in the air can gradually penetrate into the rubber and react with unsaturated bonds in the rubber to form peroxides, which can damage the polymer structure of the rubber. This oxidative aging process can continuously reduce the tensile strength of the waterstop, especially in well-ventilated but unprotected tunnel joints, the tensile strength of the waterstop may decrease within a few years, causing leakage problems.

[0005] At the same time, the chemical corrosion resistance of existing waterstop needs to be improved. In some industrial water or acid-base environments, such as the spillway tunnel of some water conservancy hubs, the water body may contain corrosive chemicals that can react with the waterstop material, damaging its surface and internal structure and shortening its service life.

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

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

[0008] To achieve the above object, the technical scheme adopted by the present application is: an aging-resistant water stop belt is made from the following raw materials in parts by mass: chloroprene rubber 40-60 parts, natural rubber 10-20 parts, ethylene-propylene-diene rubber 10-20 parts, carbon black 15-30 parts, white carbon black 5-15 parts, plasticizer 5-15 parts, sulfur 0.5-2 parts, accelerator 0.5-1.5 parts, anti-aging ultraviolet light absorber 1-2 parts, aluminum hydroxide 5-15 parts, stearic acid 1-3 parts, zinc oxide 3-8 parts;

[0009] The anti-aging ultraviolet light absorber is a structure shown in formula 1:

[0010] Formula 1;

[0011] The Z1 is selected from: O, S, N(R1), C(CH3)2, C(CD3)2;

[0012] The R1 is selected from: H, methyl, tert-butyl, phenyl, deuterated methyl, deuterated tert-butyl, deuterated phenyl.

[0013] Further, the plasticizer is dioctyl phthalate.

[0014] Further, the accelerator is diphenyl disulfide.

[0015] Further, the anti-aging ultraviolet light absorber is any one of the compounds shown in the following structures:

[0016] .

[0017] Further, the synthesis steps of the anti-aging ultraviolet light absorber are:

[0018] ;

[0019] Step 1: raw material 1 and raw material 2 are subjected to Williamson synthesis reaction to synthesize intermediate 1;

[0020] Step 2: intermediate 1 is subjected to boronation to synthesize intermediate 2;

[0021] Step 3: intermediate 2 and raw material 3 are subjected to Suzuki coupling reaction to synthesize the anti-aging ultraviolet light absorber.

[0022] A preparation method of an aging-resistant water stop belt, comprising the following steps:

[0023] S1. Mix the chlorobutyl rubber, natural rubber, ethylene propylene diene rubber at 80-100℃ for 5-15min;

[0024] S2. Add the carbon black, white carbon black, zinc oxide, stearic acid, and heat to 110-130℃ for 5-15min;

[0025] S3. Cool to 80-90℃, add the plasticizer, anti-aging ultraviolet absorber, aluminum hydroxide, and mix for 5-8min;

[0026] S4. Mix the rubber obtained in S3 with the sulfur and accelerator, and pass through 3-5 times, shape into a sheet and stand for 12-24h;

[0027] S5. Perform vulcanization treatment on the sheet after standing, with treatment conditions of 150-160℃, 10-15MPa for 20-30min, and after cooling, obtain an anti-aging water stop belt.

[0028] Further, the standing in S4 is performed under light-proof conditions.

[0029] Further, the vulcanization treatment in S5 further includes heat curing at 50-60℃ for 4-6h.

[0030] Further, the cooling process in S5 uses gradient cooling, with an initial cooling rate of 20-30℃ / min.

[0031] Further, the gradient cooling process is divided into three stages: the first stage is cooled at a rate of 20-30℃ / min to 105-95℃, the second stage is cooled at a rate of 10-15℃ / min to 55-45℃, and the third stage is naturally cooled to room temperature.

[0032] An anti-aging water stop belt for use in the application of water stop in bridge expansion joints, tunnel joints, or deformation joints in water conservancy projects.

[0033] The molecular structure of the anti-aging ultraviolet light absorber has the following characteristics: there is a large pi conjugated system (such as benzotriazole or similar structure) in the molecule, which can absorb ultraviolet light in the wavelength range of 280-400 nm, and convert the ultraviolet energy into heat energy through pi→pi* electron transition. The selection of the substituent Z1 can adjust the electron cloud distribution of the conjugated system and optimize the absorption wavelength range. The S atom has stronger electron-donating ability, which can enhance the absorption of long-wave ultraviolet (UVA). The dissociation energy of C-D bond is significantly higher than that of C-H bond, and it is more difficult to break under ultraviolet irradiation. The C-D vibration frequency of deuterated phenyl is lower than that of C-H, which reduces the matching degree with ultraviolet photon energy and reduces the photodegradation reaction. The N and S heteroatoms in the molecule can act as free radical traps, and the electron-donating groups on the benzene ring can improve the antioxidant activity of the phenolic hydroxyl group, and its antioxidant capacity is higher than that of traditional anti-aging agents. The antioxidant mechanism of the phenolic hydroxyl group in the molecule is mainly realized through two paths of hydrogen atom transfer (HAT) and single electron transfer (SET). The O-H bond has a lower bond dissociation energy, which preferentially provides hydrogen atoms to free radicals to generate stable phenolic oxygen radicals, which are stabilized by the conjugation of the benzene ring and the electronic effect of the substituent; finally, an antioxidant system with rapid reaction and persistent protection is formed.

[0034] The components of the present application form a multi-level protection system through synergistic effect: chloroprene rubber and ethylene propylene diene rubber form an interpenetrating network, and the co-vulcanization crosslinking points make the ozone resistance improve by 50% and inhibit stress cracking; carbon black and white carbon black form a two-phase filling system, the former achieves >95% ultraviolet shielding rate, and the latter releases anti-aging agents through silicon hydroxyl hydrogen bonds, which increases the tear resistance by 40%; aluminum hydroxide decomposes endothermically at 220°C, and cooperates with gradient cooling process, finally forming a comprehensive protection system with anti-ultraviolet, ozone resistance, flame retardation and fatigue resistance.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] 1. The aging resistance is significantly improved: by introducing the anti-aging ultraviolet light absorber and the composite rubber system, a multi-level protection network is formed, which effectively inhibits the material degradation caused by ultraviolet light, ozone and oxidation factors, and prolongs the service life of the waterproof belt in complex environments.

[0037] 2. The ultraviolet absorption range is widened: the synergistic effect of the optimized anti-aging ultraviolet light absorber and the heteroatoms in the large pi conjugated system enhances the absorption capacity of long-wave ultraviolet light, realizes wider wavelength range of ultraviolet shielding, and effectively prevents

[0038] 3. The antioxidant stability is enhanced: the active groups in the anti-aging ultraviolet light absorber significantly reduce the rate of chain oxidation reaction induced by free radicals through the dual antioxidant mechanism (hydrogen atom transfer and electron transfer), and maintain the long-term stability of the rubber molecular structure.

[0039] 4. Material mechanical property optimization: synergistic reinforcement of composite rubber and dual-phase filler, combined with gradient vulcanization process, to make the waterstop maintain excellent elastic recovery ability and tear resistance in long-term use, to adapt to the dynamic deformation requirements of engineering joints. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The synthesis steps of the anti-aging ultraviolet absorber described in the present application. DETAILED DESCRIPTION

[0041] The technical solutions of the present application will be described in detail below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0042] Synthesis Example 1

[0043] Synthesis of anti-aging ultraviolet absorber 1:

[0044] ;

[0045] First step: under nitrogen atmosphere, 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 are added into the reaction system, heated to 85℃ for 16h; after cooling, the obtained reaction mixture is extracted with ammonia solution and methyl tert-butyl ether, the organic phase is washed with water five times, and then washed with saturated NaCl solution twice; finally, the combined organic phase is dried with anhydrous Na2SO4, rotary evaporation, silica gel column purification, using a mixture of petroleum ether and ethyl acetate as eluent, rotary evaporation of the solution, 26.98g of intermediate 1 is obtained. MS [MS+H + ]: 504.

[0046] Second step: under nitrogen atmosphere, 26.98g of intermediate 1 and 300g of super dry tetrahydrofuran are added into the reaction system, cooled to-70℃, 3.63g of n-butyllithium is added dropwise, stirred for 1h after dropwise addition, 15.09g of triisopropyl borate is added dropwise, after dropwise addition, the temperature is allowed to rise to room temperature naturally, reacted for 12h, rotary evaporation, 19.82g of intermediate 2 is obtained. MS [MS+H + ]: 470.

[0047] Third step: under nitrogen atmosphere, 19.82 g of intermediate 2, 24.75 g of raw material 3, 1.46 g of tetrakis(triphenylphosphine)palladium, 11.67 g of potassium carbonate and 200 g of a mixed solution of toluene, ethanol and water (volume ratio 2:1:1) were added into the reaction system, heated to 75°C and refluxed for 10 hours, the heating was turned off, cooled to room temperature, and then separated into two layers. The aqueous phase was extracted with ethyl acetate twice, the organic phases were combined, washed with water three times, dried and then purified by silica gel column with a mixed solution of petroleum ether and ethyl acetate as eluent. The solution was dried to obtain 28.47 g of anti-aging ultraviolet absorber 1. MS [MS+H + ] : 833.

[0048] The structure of anti-aging ultraviolet absorber 1 1 HNMR (deuterated chloroform) δ 8.10 (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), 4.51-4.42 (m, 2H), 4.23 (dd, 1H), 3.37-3.27 (m, 1H), 3.13-3.04 (m, 1H), 2.02 (d, 2H).

[0049] Synthesis Examples 2-7

[0050] The anti-aging ultraviolet absorbers synthesized in Synthesis Examples 2-7 were synthesized according to the synthesis method of Synthesis Example 1, with the raw material 2 replaced and the rest unchanged. The structures of the raw material 2, the anti-aging ultraviolet absorber and the MS [MS+H + ] data are shown in the following table.

[0051]

[0052] Ultraviolet maximum absorption peak test: the compounds prepared in Synthesis Examples 1-7 were configured into 10 -5 Mg / L of tetrahydrofuran solution, and the ultraviolet maximum absorption peak of 200-450 nm was determined.

[0053] DPPH radical scavenging experiment: DPPH solid was configured into a DPPH test solution of 50 μM, and the absorbance was 0.45. Sample solution configuration: the sample (compound prepared in synthesis example 1-synthesis example 7) was dissolved with ethanol to prepare a 20 mM solution, and before testing, the 20 mM sample solution was diluted with ethanol to 500 μM, and then diluted with ethanol to 40 μM for testing. A value measurement (test group): in a 96-well plate, 40 μL of the sample solution was taken with a pipette, and 160 μL of the DPPH solution was added. After 8 h at room temperature, the A519 nm value was measured. A0 value measurement (blank group): 40 μL of ethanol solution was taken with a pipette, and 160 μL of DPPH solution was added, and the measured A value was A0.

[0054] The ultraviolet absorption antioxidant prepared in synthesis example 1-synthesis example 7 has the ultraviolet maximum absorption peak and DPPH radical scavenging rate as shown in the following table.

[0055]

[0056] Example 1

[0057] A preparation method of an anti-aging water stop belt, and the specific steps are as follows:

[0058] Raw material ratio (mass fraction): chlorobutyl rubber 50 parts, natural rubber 15 parts, ternary ethylene-propylene rubber 15 parts, carbon black 22 parts, white carbon black 10 parts, dioctyl phthalate (plasticizer) 10 parts, sulfur 1.2 parts, diphenyl disulfide (accelerator) 1.0 part, anti-aging ultraviolet absorption agent (compound synthesized in synthesis example 1) 1.5 parts, aluminum hydroxide 10 parts, stearic acid 2 parts, zinc oxide 5 parts.

[0059] Preparation steps:

[0060] S1. The chlorobutyl rubber, natural rubber and ternary ethylene-propylene rubber were added to the internal mixer, and mixed at 90°C for 10 min to form a uniform glue;

[0061] S2. The carbon black, white carbon black, zinc oxide and stearic acid were added to the internal mixer, and the temperature was raised to 120°C, and the mixing was continued for 10 min;

[0062] S3. The temperature was reduced to 85°C, and the dioctyl phthalate, anti-aging ultraviolet absorption agent (compound synthesized in synthesis example 1) and aluminum hydroxide were added, and mixed for 6 min;

[0063] S4. The glue was transferred to the open mill, and the sulfur and accelerator were added, and after 4 times of thin passing, it was calendered into a sheet with a thickness of 5 mm. The sheet was placed in a light-proof environment for 18 hours;

[0064] S5. Vulcanization treatment: The sheet was placed in a flat vulcanization machine and vulcanized at 155°C under a pressure of 12 MPa for 25 min. Gradient cooling: first stage: cooling to 100°C at a rate of 25°C / min; second stage: cooling to 50°C at a rate of 12°C / min; third stage: cooling to room temperature;

[0065] Hot curing: the vulcanized sheet was hot cured in an oven at 55°C for 5 hours to further stabilize the crosslinked network, obtaining an anti-aging water stop belt.

[0066] Examples 2-7

[0067] An anti-aging water stop belt was prepared according to the preparation method of Example 1, wherein the anti-aging ultraviolet light absorber was replaced by the compound synthesized in Synthetic Example 2-Synthetic Example 7 in turn, and the rest was the same as Example 1.

[0068] Comparative Example 1

[0069] An anti-aging water stop belt was prepared according to the preparation method of Example 1, wherein the anti-aging ultraviolet light absorber was replaced by the compound synthesized in Synthetic Example 2-Synthetic Example 7 in turn, and the rest was the same as Example 1.

[0070] The structure of Comparative Compound 1 is: .

[0071] Comparative Example 3

[0072] An anti-aging water stop belt was prepared according to the preparation method of Example 1, wherein the anti-aging ultraviolet light absorber was replaced by the compound synthesized in Synthetic Example 2-Synthetic Example 7 in turn, and the rest was the same as Example 1.

[0073] Performance test:

[0074] Anti-ultraviolet aging property: The water stop belt (an anti-aging water stop belt prepared in Examples 1-7, Comparative Examples 1-3) was cut into dumbbell-shaped samples of equal size according to the method specified in GB / T9865.1, and pretreated according to the artificial climate aging (fluorescent ultraviolet lamp) test method for vulcanized rubber in GB / T16585-1996. Four hours of light and four hours of cooling constitute one cycle, and the dumbbell-shaped water stop belt sample is taken out after three cycles of light and cooling. The anti-ultraviolet aging property of the water stop belt is reflected by the tensile stress and strain performance of the water stop belt after being irradiated by ultraviolet light. The tensile stress and strain performance of the water stop belt was measured according to GBT528-1998. The dumbbell-shaped water stop belt sample was placed evenly on the upper and lower clamps of a constant-speed tensile testing machine, and then stretched. The testing machine was started to detect. The higher the tensile strength, breaking tensile strength and elongation at break, the better the anti-ultraviolet aging property.

[0075]

[0076] The mechanical properties of the example samples are significantly better than those of the comparative samples, which reflects 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 within the upper limit of the technical index, while the performance of the comparative samples presents a stepwise decline due to the lack of key structural design. Through the longitudinal comparison between the examples, it can be seen that the antioxidant containing specific heteroatoms and conjugated structures (such as examples 6-7) effectively inhibits the molecular chain rupture caused by ultraviolet light during the aging process, and its mechanical retention ability is significantly better than that of the conventional system, which verifies the decisive role of structural optimization on the durability of the material.

[0077] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application 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 weight: 40-60 parts chloroprene rubber, 10-20 parts natural rubber, 10-20 parts EPDM rubber, 15-30 parts carbon black, 5-15 parts silica, 5-15 parts plasticizer, 0.5-2 parts sulfur, 0.5-1.5 parts accelerator, 1-2 parts anti-aging UV absorber, 5-15 parts aluminum hydroxide, 1-3 parts stearic acid, and 3-8 parts zinc oxide; The anti-aging ultraviolet absorber is any one of the compounds shown in the following structures: 。 2. The aging-resistant waterstop according to claim 1, characterized in that, The plasticizer is dioctyl phthalate.

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

4. A method for preparing an aging-resistant waterstop according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Mix the chloroprene rubber, natural rubber, and EPDM rubber at 80-100℃ for 5-15 minutes; S2. Add the carbon black, silica, zinc oxide, and stearic acid, and heat to 110-130℃ to mix for 5-15 minutes; S3. Cool to 80-90℃, add the plasticizer, anti-aging UV absorber, and aluminum hydroxide, and mix for 5-8 minutes; S4. Mix the rubber compound obtained in S3 with the sulfur and accelerator, then pass it through a thin sheet 3-5 times to form a sheet and let it stand for 12-24 hours. S5. After standing, the sheet is subjected to vulcanization treatment under the following conditions: 150-160℃ and 10-15MPa for 20-30 minutes. After cooling, an aging-resistant waterstop is obtained.

5. The method for preparing an aging-resistant waterstop according to claim 4, characterized in that, The resting process described in S4 is carried out under light-protected conditions.

6. The method for preparing an aging-resistant waterstop according to claim 4, characterized in that, The vulcanization treatment described in S5 also includes heat curing at 50-60℃ for 4-6 hours.

7. The method for preparing an aging-resistant waterstop according to claim 4, characterized in that, The cooling process described in S5 employs gradient cooling with an initial cooling rate of 20-30℃ / min.

8. The method for preparing an aging-resistant waterstop according to claim 7, characterized in that, The gradient cooling process is divided into three stages: the first stage cools down to 105-95℃ at a rate of 20-30℃ / min, the second stage cools down to 55-45℃ at a rate of 10-15℃ / min, and the third stage cools down naturally to room temperature.

9. The application of an aging-resistant waterstop as described in any one of claims 1-3 in waterstopping of bridge expansion joints, tunnel joints, or deformation joints in hydraulic engineering projects.

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