Durable anti-aging waterstop and preparation method and application thereof

Abstract

The application discloses a durable anti-aging waterstop and a preparation method and application thereof, and relates to the technical field of high polymer waterproof materials. The durable anti-aging waterstop comprises the following components in parts by mass: a rubber matrix 100 parts, reinforcing fillers 30-60 parts, vulcanizing agents 2-5 parts, anti-aging agents 2-5 parts, nano-zinc oxide 3-8 parts, stearic acid 0.5-2 parts and accelerators 1.5-4 parts. Compared with the prior art, the anti-aging agent has a single function and is insufficient in ultraviolet protection. The anti-aging agent with a specific structure and the nano-zinc oxide and other components are synergized to construct a dual-protection mechanism of physical shielding and chemical conversion, so that the ultraviolet light energy can be more effectively blocked and converted, and the aging process of the waterstop in an outdoor environment can be significantly delayed.

Description

Technical Field

[0001] This invention relates to the field of polymer waterproof materials technology, specifically to a durable anti-aging waterstop strip, its preparation method, and its application. Background Technology

[0002] In the field of outdoor waterproofing and sealing, UV-resistant waterstops are key components of concrete expansion joints, settlement joints, and deformation joints, and their long-term performance stability directly affects project safety. Currently, other similar products in the industry mainly improve their anti-aging capabilities by adding ordinary antioxidants or single UV absorbers, but these methods have significant limitations. Ordinary antioxidants primarily target the thermo-oxidative aging process and have a weak shielding effect against UV radiation. They are unable to effectively block the polymer chain breakage and decreased cross-linking degree caused by UV light, leading to hardening, embrittlement, and loss of elasticity of the waterstop after long-term outdoor exposure, resulting in cracking and leakage. Meanwhile, single UV absorbers are prone to migration or decomposition during long-term use, resulting in insufficient protective durability and failing to meet the long-term waterproofing reliability requirements of infrastructure such as bridges and tunnels.

[0003] In terms of material preparation, while the selection of fillers in traditional processes can provide some reinforcement and light-shielding effects, they lack a systematic ultraviolet protection mechanism and cannot fully resist the penetrating degradation of ultraviolet rays. If the amount of reinforcing filler is insufficient or the dispersion is uneven, it can easily lead to a decline in the local mechanical properties of the material and accelerate the formation of aging weaknesses. In addition, the combination of conventional vulcanization systems and accelerators fails to fully consider the stability of the cross-linked network under ultraviolet conditions, making it difficult for the waterstop to maintain dimensional stability and elastic recovery ability under long-term stress or heat.

[0004] Existing antioxidants have relatively simple structures and functions. Most products fail to combine UV absorption with molecular-level conjugated stabilization mechanisms, resulting in insufficient protection in complex outdoor environments. Furthermore, if the mixing process is not carried out under a protective atmosphere, the oxidation risk during high-temperature processing will further weaken the activity and dispersion of antioxidants, affecting the uniformity and durability of the final product. Summary of the Invention

[0005] This invention addresses the problems of existing antioxidants having limited functionality, insufficient UV protection, poor material durability, and oxidation risks in the preparation process. It provides a durable anti-aging waterstop with significant and long-lasting UV shielding effectiveness, synergistic enhancement of physical and chemical protection, excellent cross-linking network stability, good component dispersion uniformity, and a mixing process carried out under a protective atmosphere that effectively maintains the activity of the antioxidant, as well as its preparation method and application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A durable anti-aging waterstop, by weight, comprises the following components: 100 parts rubber matrix, 30-60 parts reinforcing filler, 2-5 parts vulcanizing agent, 2-5 parts anti-aging agent, 3-8 parts nano zinc oxide, 0.5-2 parts stearic acid, and 1.5-4 parts accelerator. The general formula of the antioxidant is shown in Formula 1: Formula 1; R1 is selected from: hydrogen, methyl, trifluoromethyl, hydroxyl, methoxy.

[0007] Furthermore, the rubber matrix is ​​at least one of EPDM rubber, chloroprene rubber, natural rubber, styrene-butadiene rubber, and polyisobutylene.

[0008] Furthermore, the reinforcing filler is at least one of carbon black, silica, calcium carbonate, or kaolin.

[0009] Furthermore, the vulcanizing agent is sulfur.

[0010] Furthermore, the accelerator is a compound combination of accelerator TMTD and accelerator M, with a mass ratio of 1:(1-1.5).

[0011] Furthermore, the antioxidant is any one of the compounds shown in the following structures: ; .

[0012] A method for preparing a durable anti-aging waterstop includes the following steps: (1) Raw material pretreatment: Dry the rubber matrix at 60-80℃ for 1-2 hours to remove surface moisture; pass the reinforcing filler and nano zinc oxide through a 200-300 mesh sieve to ensure uniform particle dispersion; (2) First stage of mixing: Under the protection of nitrogen, the pretreated rubber matrix is ​​added to the internal mixer, and then the reinforcing filler, nano zinc oxide and stearic acid are added in sequence for preliminary mixing; after the material forms a uniform rubber compound, the vulcanizing agent, antioxidant and accelerator are added, and mixing continues until all components are completely integrated to obtain the compound. (3) Hot feed extrusion: The compound is added to a hot feed extruder and extruded into a stop-water strip preform; (4) Saturated steam vulcanization: The waterstop blank is placed in a vulcanization tank and saturated steam is introduced to complete the cross-linking reaction; after vulcanization, it is naturally cooled to room temperature to obtain a durable anti-aging waterstop.

[0013] Furthermore, the specific parameters for the mixing stage in step (2) are: mixing temperature 80-100℃, total mixing time 10-15min; The initial mixing time is 5-8 minutes, and the continued mixing time is 2-7 minutes.

[0014] Furthermore, the parameters for hot feeding extrusion in step (3) are: barrel temperature controlled in segments, first segment 110-120℃, second segment 120-130℃, die head temperature 120-140℃, and extrusion rate 2-5m / min; The parameters for step (4) saturated steam vulcanization are: vulcanization temperature 150-170℃, vulcanization pressure 0.5-1.0MPa, vulcanization time 15-30min, of which the vulcanization time for waterstop with a thickness of 5-10mm is 15-20min, and the vulcanization time for waterstop with a thickness of 10-20mm is 20-30min.

[0015] Furthermore, the durable anti-aging waterstop described herein is used in the waterproof sealing of concrete expansion joints, settlement joints, and deformation joints exposed to outdoor ultraviolet environments.

[0016] The core component of this invention's UV-resistant waterproofing tape effectively blocks and converts ultraviolet light energy through a dual mechanism of physical shielding and chemical transformation, thereby slowing down the photo-oxidative aging process of polymer materials. This component works synergistically with various functional materials: nano-zinc oxide reflects and scatters ultraviolet light through surface effects and forms charge-transfer complexes with a specific structured anti-aging agent, converting ultraviolet photons into heat energy; reinforcing fillers improve the material's mechanical properties while providing additional light-shielding effects; vulcanizing agents and accelerators combine to form a stable cross-linked network, ensuring the material's dimensional stability in long-term outdoor environments; stearic acid improves the uniformity of dispersion of each component in the matrix, preventing the formation of localized protective weaknesses.

[0017] The components achieve long-lasting protection through multiple synergistic mechanisms. The rubber matrix, as the continuous phase, provides basic elasticity and sealing properties. Nano-zinc oxide and antioxidants synergistically construct a UV protective layer that transforms physical reflection into molecular-level energy conversion. Reinforcing fillers and the vulcanization system jointly enhance the material's tear resistance and cross-linking density, while stearic acid ensures the uniform distribution of functional components during processing. A nitrogen-protected one-stage mixing process further reduces the impact of high-temperature processing on the activity of antioxidants, while hot-feed extrusion and saturated steam vulcanization processes ensure the sufficiency of the waterstop preform molding and cross-linking reaction. This multi-layered synergistic effect enables the waterstop to maintain its elastic recovery and sealing reliability in outdoor UV environments such as concrete expansion joints, significantly extending the service life of engineering waterproofing components.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. Superior UV aging resistance: Compared with the problems of single function and insufficient UV protection of existing anti-aging agents, the present invention constructs a dual protection mechanism of physical shielding and chemical conversion through the synergistic effect of anti-aging agents with specific structures and components such as nano zinc oxide. This can more effectively block and convert UV light energy, and significantly delay the aging process of the waterstop in the outdoor environment.

[0019] 2. More stable mechanical properties and durability: Overcoming the problems of uneven filler dispersion and poor compatibility of vulcanization system in existing technologies, resulting in localized weak performance, this invention optimizes the amount of reinforcing filler, compound accelerator and nitrogen-protected mixing process, so that the waterstop has better initial mechanical properties and better performance retention after long-term outdoor exposure, and is less prone to hardening, embrittlement or loss of elasticity.

[0020] 3. Enhanced applicability to outdoor projects: Addressing the limitations of existing products in meeting the long-term waterproofing requirements of infrastructure such as bridges and tunnels, the waterstop of this invention is better suited to the waterproofing and sealing needs of concrete expansion joints, settlement joints, and other scenarios under outdoor ultraviolet environments, maintaining reliable sealing for a long time and extending the service life of waterproofing components in engineering projects. Attached Figure Description

[0021] Figure 1 This is a method for synthesizing the antioxidant described in this invention.

[0022] Figure 2 This is the NMR spectrum of the antioxidant 1 described in this invention. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Preparation Example 1 Preparation of antioxidant 1: ; In the first step, under nitrogen protection, 3.00 g of raw material 1, 1.80 g of raw material 2, and 36 mL of a mixed solvent of dioxane and diisopropylamine (24 mL / 12 mL) were added sequentially to a dry reaction system. After stirring evenly, 0.10 g of palladium acetate, 0.15 g of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, and 0.07 g of CuI were added sequentially. After stirring evenly, the mixture was heated to 85 °C and refluxed for 6 h. After the reaction was completed, the mixture was cooled to room temperature and filtered. The filter cake was washed three times with tetrahydrofuran. The solvent in the filtrate was removed by a rotary evaporator, and the filtrate was purified by silica gel column chromatography using a mixed solution of petroleum ether and ethyl acetate as the eluent. The eluent was removed by a rotary evaporator to obtain 3.21 g of intermediate 1. In the second step, under a nitrogen atmosphere, 3.21 g of intermediate 1, 2.01 g of raw material 3, and 40 ml of toluene were added to the reaction system. After stirring until homogeneous, 0.05 g of triphenylphosphine, 0.02 g of palladium on carbon, and 2.30 g of triethylamine were added under a continuous nitrogen flow. After stirring until homogeneous, the mixture was heated to 120 °C and refluxed for 12 hours. After the reaction was completed, the solvent was evaporated. The crude product was then added to 30 ml of ethanol, stirred, heated to 80 °C, and refluxed for 2 hours. After cooling to room temperature, the mixture was filtered, and the filtrate was evaporated to dryness. Silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate as eluent. The solvent was evaporated to dryness again to obtain 3.86 g of antioxidant 1.

[0025] Compound structure identification data: Mass spectrometry (MS) of intermediate 1 [MS+1]: 460; Mass spectrometry (MS) of antioxidant 1 [MS+1]: 712; See NMR for antioxidant 1 Figure 1 .

[0026] Preparation Examples 2-4 In Preparation Examples 2-4, antioxidant 2-antioxidant 4 were prepared sequentially, following the preparation method of Preparation Example 1, except that raw material 2 was replaced, while the rest remained the same as in Preparation Example 1.

[0027] The specific structures of raw material 2, antioxidant 2 and antioxidant 4, and their mass spectrometry (MS+1) data are shown in Table 1.

[0028] Table 1 Preparation of a durable, anti-aging waterstop: 1. Raw material preparation: By mass, 100 parts of EPDM rubber are selected as the rubber matrix, 45 parts of carbon black as the reinforcing filler, 3 parts of sulfur as the vulcanizing agent, 1.3 parts of the antioxidant obtained in Example 1, 5 parts of nano zinc oxide, 1 part of stearic acid, and the accelerator is a compound combination of accelerator TMTD and accelerator M (mass ratio of the two is 1:1.2, of which TMTD is 0.8 parts and M is 1.0 parts).

[0029] 2. Raw material pretreatment: Place EPDM rubber in a 70℃ oven and dry for 1.5 hours to remove surface moisture; pass carbon black and nano zinc oxide through a 250-mesh sieve to ensure uniform particle dispersion. 3. First stage of mixing: Under a nitrogen protective atmosphere, the pretreated EPDM rubber is added to the internal mixer, followed by the sieved carbon black, nano zinc oxide and stearic acid. The mixture is initially mixed at 90°C for 6 minutes. After the material forms a uniform rubber compound, sulfur, antioxidant 1 and compound accelerator are added. The mixture is then mixed for another 4 minutes until all components are fully integrated to obtain the compound (total mixing time 10 minutes). 4. Hot feed extrusion: Add the compounded rubber to the hot feed extruder. The barrel temperature is controlled in sections: 115℃ for the first section, 125℃ for the second section, and 130℃ for the die head. Extrusion is carried out at an extrusion rate of 3m / min to obtain a waterstop preform with a thickness of 8mm. 5. Saturated steam vulcanization: Place the waterstop blank into a vulcanization tank, introduce saturated steam, control the vulcanization temperature at 160℃ and the vulcanization pressure at 0.8MPa, and complete the cross-linking reaction in 18 minutes. After vulcanization, allow it to cool naturally to room temperature to obtain the UV-resistant waterstop.

[0030] Examples 2 to 4 The preparation of a durable anti-aging waterstop is carried out by referring to the preparation method of Example 1, except that the antioxidants are replaced sequentially with antioxidants 2-4, and the rest is the same as in Example 1.

[0031] Comparative Example 1 The preparation of a durable anti-aging waterstop is carried out according to the preparation method of Example 1, except that the anti-aging agent is not added, and the rest is the same as in Example 1.

[0032] Comparative Example 2 The preparation of a durable anti-aging waterstop is carried out according to the preparation method of Example 1, except that the anti-aging agent is replaced with... The rest remains the same as in Example 1.

[0033] Comparative Example 3 The preparation of a durable anti-aging waterstop is carried out by referring to the preparation method of Example 1, except that the antioxidant is replaced with antioxidant AW, and the rest is the same as in Example 1.

[0034] Comparative Example 4 The preparation of a durable anti-aging waterstop is carried out by referring to the preparation method of Example 1, except that the mass fraction of the reinforcing filler is replaced with 25 parts, and the rest remains the same as in Example 1.

[0035] Comparative Example 5 The preparation of a durable anti-aging waterstop is carried out by referring to the preparation method of Example 1, except that the mass fraction of nano zinc oxide is replaced with 2 parts, and the rest is the same as in Example 1.

[0036] Performance testing 1. Tensile strength was tested according to GB / T18173.2-2014.

[0037] 2. Place the sample under an irradiation intensity of 0.51 W / (m²). 2 The tensile strength was tested at 65±3℃ and 50±10% relative humidity for 2000 hours, with a blackboard temperature of 65±3℃ and a relative humidity of 50±10%. The tensile strength retention rate was calculated according to GB / T18173.2-2014.

[0038] Table 2 The samples using the specific antioxidant of this invention generally exhibited better initial tensile strength than samples without this type of antioxidant, samples using other types of antioxidants, and samples with reduced amounts of reinforcing filler or nano zinc oxide. After ultraviolet irradiation, the tensile strength retention rate of the former was significantly higher than that of the samples without this type of antioxidant or those replaced with other antioxidants. While the strength retention rate of the samples with reduced amounts of reinforcing filler or nano zinc oxide was better than that of the samples with replaced antioxidants or no antioxidants, it was still lower than that of the samples using the specific antioxidant of this invention. This indicates that the antioxidant of this invention can effectively improve the initial mechanical properties and UV aging stability of the waterstop, and the appropriate amount of reinforcing filler and nano zinc oxide also has a positive effect on performance.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A durable, anti-aging waterstop, characterized in that, By weight, it includes the following components: 100 parts rubber matrix, 30-60 parts reinforcing filler, 2-5 parts vulcanizing agent, 2-5 parts antioxidant, 3-8 parts nano zinc oxide, 0.5-2 parts stearic acid, and 1.5-4 parts accelerator. The general formula of the antioxidant is shown in Formula 1: Formula 1; R1 is selected from: hydrogen, methyl, trifluoromethyl, hydroxyl, methoxy.

2. The durable anti-aging waterstop according to claim 1, characterized in that, The rubber matrix is ​​at least one of EPDM rubber, chloroprene rubber, natural rubber, or styrene-butadiene rubber.

3. The durable anti-aging waterstop according to claim 1, characterized in that, The reinforcing filler is at least one of carbon black, silica, calcium carbonate, or clay.

4. The durable anti-aging waterstop according to claim 1, characterized in that, The vulcanizing agent is sulfur.

5. A durable anti-aging waterstop according to claim 1, characterized in that, The accelerator is a compound combination of accelerator TMTD and accelerator M, with a mass ratio of 1:(1-1.5).

6. A durable anti-aging waterstop according to claim 1, characterized in that, The antioxidant is any one of the compounds shown in the following structures: ； 。 7. A method for preparing a durable anti-aging waterstop as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Raw material pretreatment: Dry the rubber matrix at 60-80℃ for 1-2 hours to remove surface moisture; pass the reinforcing filler and nano zinc oxide through a 200-300 mesh sieve to ensure uniform particle dispersion; (2) First stage of mixing: Under the protection of nitrogen, the pretreated rubber matrix is ​​added to the internal mixer, and then the reinforcing filler, nano zinc oxide and stearic acid are added in sequence for preliminary mixing; after the material forms a uniform rubber compound, the vulcanizing agent, antioxidant and accelerator are added, and mixing continues until all components are completely integrated to obtain the compound. (3) Hot feed extrusion: The compound is added to a hot feed extruder and extruded to form a stop-water strip preform; (4) Saturated steam vulcanization: The waterstop blank is placed in a vulcanization tank and saturated steam is introduced to complete the cross-linking reaction; after vulcanization, it is naturally cooled to room temperature to obtain a durable anti-aging waterstop.

8. The method for preparing a durable anti-aging waterstop according to claim 7, characterized in that, The specific parameters for the first stage of mixing in step (2) are: mixing temperature 80-100℃, total mixing time 10-15min; The initial mixing time is 5-8 minutes, and the continued mixing time is 2-7 minutes.

9. The method for preparing a durable anti-aging waterstop according to claim 7, characterized in that, The parameters for hot feeding extrusion in step (3) are: barrel temperature controlled in segments, first segment 110-120℃, second segment 120-130℃, die head temperature 120-140℃, and extrusion rate 2-5m / min; The parameters for step (4) saturated steam vulcanization are: vulcanization temperature 150-170℃, vulcanization pressure 0.5-1.0MPa, vulcanization time 15-30min, of which the vulcanization time for waterstop with a thickness of 5-10mm is 15-20min, and the vulcanization time for waterstop with a thickness of 10-20mm is 20-30min.

10. The application of a durable anti-aging waterstop as described in any one of claims 1-6 in the waterproof sealing of concrete expansion joints, settlement joints and deformation joints exposed to outdoor ultraviolet environment.

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