Environment-friendly high-strength waterstop and preparation method thereof

Abstract

The invention discloses an environment-friendly high-strength water-stop belt and a preparation method thereof, and relates to the technical field of high-molecular compound composition water-stop belts. The environment-friendly high-strength water-stop belt is prepared from the following components in parts by mass: 100 parts of ethylene propylene diene monomer, 40 to 70 parts of reinforcing filler, 10 to 25 parts of environment-friendly plasticizer, 1 to 5 parts of interface modifier, 1.5 to 3.5 parts of vulcanizing agent, 3 to 8 parts of active agent, 1 to 3 parts of anti-aging agent and 5 to 15 parts of flame retardant. White carbon black and calcium carbonate are adopted as reinforcing filler to replace traditional carbon black, and energy consumption and pollution emission in the production process are remarkably reduced. By optimizing the formula and the preparation process, the tensile strength, the elongation at break, the tearing strength and other mechanical properties of the waterstop are remarkably improved. Aluminum hydroxide is added as a flame retardant, absorbs heat during thermal decomposition and forms a barrier layer, so that oxygen is effectively diluted, and fire spreading is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of waterstop belts for polymer compound compositions, and specifically relates to an environmentally friendly high-strength waterstop belt and a preparation method thereof. Background Art

[0002] In many engineering fields such as construction, water conservancy, and transportation, waterstop belts are key materials to ensure the waterproof and sealing performance of structures. Traditional waterstop belts mainly use natural rubber, neoprene, or ethylene propylene diene monomer (EPDM) rubber as the main raw materials, and are mixed with additives such as carbon black and petroleum-based plasticizers. However, these traditional waterstop belts have many problems. Taking carbon black as an example, it has a large specific surface area, is prone to agglomeration, and has poor compatibility with rubber, resulting in limited improvement in the mechanical properties of the waterstop belt. Moreover, it is prone to cracking and leakage during long-term use, shortening the service life. Petroleum-based plasticizers are volatile at high temperatures and prone to precipitation at low temperatures, making the waterstop belt brittle, hardened, and lose its elasticity, unable to meet the strict requirements of modern projects for durability.

[0003] From an environmental protection perspective, traditional waterstop belts have many hidden dangers. The production process of carbon black has high energy consumption and heavy pollution. Moreover, after the waterstop belt is discarded, carbon black and petroleum-based plasticizers are difficult to degrade, polluting the soil and water sources. In addition, traditional waterstop belts have poor fire resistance, are prone to burning and spreading when encountering fire, generating toxic smoke, threatening the safety of personnel, and increasing fire losses, which is particularly fatal in crowded places or important engineering parts.

[0004] With the development of the times, higher requirements are put forward for waterstop belts in engineering. On the one hand, the pursuit of green and sustainable development promotes the industry to seek environmentally friendly materials. On the other hand, complex and demanding projects such as large buildings, high-speed railways, and water conservancy hubs require waterstop belts to have high strength, high elasticity, excellent durability, and good flame retardancy. For example, the basements of high-rise buildings need to resist groundwater pressure for a long time, and water conservancy dams need to withstand huge water pressure and are in a humid environment, which poses a severe test to the performance of waterstop belts. Traditional waterstop belts are already difficult to fully meet the current engineering requirements, and it is imperative to develop a new type of environmentally friendly high-strength waterstop belt to make up for the deficiencies of existing technologies and promote the progress of the industry. Summary of the Invention

[0005] The purpose of the present invention is to provide an environmentally friendly waterstop belt with high strength, excellent elasticity, and good flame retardancy in view of the problems existing in the prior art, and at the same time improve its durability and service life.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: an environmentally friendly high-strength waterstop belt, comprising the following components in parts by mass: ethylene propylene diene monomer (EPDM) rubber: 100 parts, reinforcing filler: 40 - 70 parts, environmentally friendly plasticizer: 10 - 25 parts, interfacial modifier: 1 - 5 parts, vulcanizing agent: 1.5 - 3.5 parts, activator: 3 - 8 parts, antioxidant: 1 - 3 parts, flame retardant: 5 - 15 parts; The antioxidant is a compound represented by Formula 1: Formula 1 The R1 is selected from: methyl, ethyl, propyl, phenyl, methoxy.

[0007] Furthermore, the reinforcing filler is composed of silica and calcium carbonate in a mass ratio of 1:(1.5 - 2.5).

[0008] Furthermore, the environmentally friendly plasticizer is epoxy soybean oil.

[0009] Furthermore, the interfacial modifier is γ-aminopropyltriethoxysilane.

[0010] Furthermore, the vulcanizing agent is sulfur.

[0011] Furthermore, the activator is zinc oxide.

[0012] Furthermore, the flame retardant is aluminum hydroxide.

[0013] Furthermore, the antioxidant is any one of the compounds represented by the following structures: ; .

[0014] Furthermore, the synthesis method of the antioxidant is: ; The first step: Intermediate 1 is synthesized by Buchwald-Hartwig arylamine reaction of Raw material 1 and Raw material 2; The second step: The antioxidant is synthesized by esterification reaction of Intermediate 1 and Raw material 3.

[0015] A preparation method of an environmentally friendly high-strength waterstop strip includes the following steps: S1. Plasticize the ethylene propylene diene monomer (EPDM) in a mixer to 60 - 70 °C, add the reinforcing filler, interfacial modifier and environmentally friendly plasticizer, and mix for 8 - 12 minutes to obtain Material A; S2. Heat Material A to 85 - 95 °C, add the antioxidant and flame retardant, and mix for 5 - 8 minutes to obtain Material B; S3. Cool Material B to below 70 °C, add the activator and vulcanization system, mix evenly and then take out the sheet to obtain Material C; S4. Shape Material C through an extruder and vulcanize it with a flat vulcanizer at a vulcanization temperature of 150 - 160 °C for 15 - 25 minutes to obtain an environmentally friendly high-strength waterstop strip.

[0016] Furthermore, during the mixing process in S1, the rotor speed is controlled at 40 - 60 rpm.

[0017] Further, the kneading speed in S2 is 25 - 40 rpm.

[0018] Further, after the sheet is taken out in S3, it needs to be parked and cured for 24 hours in a nitrogen atmosphere, and then enter S4 for vulcanization and molding.

[0019] Further, the vulcanization pressure is 10 - 15 MPa.

[0020] During the use of rubber, high - activity alkyl free radicals and peroxy free radicals are generated under the action of heat, oxygen, light, etc. The antioxidant described in the present invention can actively react with these free radicals to generate stable free - radical products, thereby interrupting the oxidation chain reaction. The antioxidant described in the present invention also has a certain ability to decompose hydroperoxides. Hydroperoxides are intermediate products of rubber oxidation and are extremely easy to decompose to generate new free radicals, accelerating aging. The heterocyclic ring and substituent effects in the antioxidant molecule may promote the decomposition of hydroperoxides into relatively stable non - free - radical products such as alcohols. The benzheterocyclic ring and substituent R1 in the molecular structure provide a large steric hindrance. This helps to physically hinder the contact of active substances such as oxygen molecules, ozone, and free radicals with the main chain or side chain of rubber. The selection of substituent R1 (methyl, ethyl, propyl, phenyl, methoxy) can fine - tune the polarity, solubility, volatility, and steric hindrance of the molecule, making it better compatible with the ethylene - propylene - diene monomer (EPDM) matrix, evenly dispersed, and effectively playing a role in the long term.

[0021] The ethylene propylene diene monomer (EPDM) rubber described in the present invention is used as the main matrix material, which has excellent weather resistance, ozone resistance and elasticity. Its saturated main chain structure combines with antioxidants and flame retardants, significantly improving the anti-aging ability. In the reinforcing filler (silica + calcium carbonate), silica replaces traditional carbon black, providing high reinforcement (enhancing tensile strength and wear resistance), and is environmentally friendly and pollution-free; calcium carbonate reduces costs, improves processing fluidity, and the ratio with silica can prevent agglomeration. Silica reacts with the interfacial modifier (silane) through silanol groups to enhance the binding force with the rubber; calcium carbonate fills the voids, synergistically improving the compactness and compressive strength of the water stop belt. The environmentally friendly plasticizer (epoxidized soybean oil) replaces petroleum-based plasticizers, is non-toxic and biodegradable, and the epoxy groups participate in vulcanization cross-linking, reducing volatilization and migration; it synergistically improves the flexibility of the rubber compound with silica, avoiding embrittlement at low temperatures. The interfacial modifier (γ-aminopropyltriethoxysilane) acts as a "molecular bridge" to connect the inorganic fillers (silica / calcium carbonate) and the rubber, reacts with the hydroxyl groups of silica, improving the filler dispersion; reducing interfacial defects, significantly improving the tear strength of the water stop belt. The heterocyclic ring in the antioxidant captures free radicals; the substituent R1 provides steric hindrance, blocking oxygen diffusion; decomposing hydroperoxides, terminating the oxidation chain reaction, and synergistically with the saturated structure of EPDM, resisting ultraviolet and thermo-oxidative aging; the molecular polarity design ensures its uniform dispersion in the rubber, being effective for a long time. The flame retardant (aluminum hydroxide) absorbs heat during decomposition, dilutes oxygen and forms a barrier layer, is compatible with the environmentally friendly plasticizer (epoxidized soybean oil), avoiding the precipitation of the flame retardant; the decomposition product alumina combines with the rubber cross-linking network, enhancing the stability of the carbon layer.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Improvement in environmental performance: The present invention uses silica and calcium carbonate as reinforcing fillers, replacing traditional carbon black, significantly reducing energy consumption and pollution emissions during the production process. At the same time, the use of biodegradable epoxidized soybean oil to replace petroleum-based plasticizers reduces environmental pollution, making the water stop belt more easily degradable after being discarded, effectively protecting the soil and water sources.

[0023] 2. Enhancement of mechanical properties: Through optimizing the formulation and preparation process, the mechanical properties such as the tensile strength, elongation at break and tear strength of the water stop belt have been significantly improved.

[0024] 3. Improvement in flame retardancy and durability: The present invention adds aluminum hydroxide as a flame retardant, which absorbs heat and forms a barrier layer during decomposition, effectively diluting oxygen and preventing the spread of fire. At the same time, the heterocyclic structure and substituent R1 in the antioxidant provide steric hindrance, which can capture free radicals and decompose hydroperoxides, thus significantly extending the service life of the water stop belt and reducing maintenance costs. Description of the Drawings

[0025] Figure 1 HNMR spectrum of antioxidant 1 described in the present invention 1 HNMR spectrum.

[0026] Figure 2 The invention discloses a method for synthesizing the antioxidant of the invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0028] Synthesis example 1 Synthesis of antioxidant 1: ; The first step: under a nitrogen atmosphere, 20.00 g of raw material 1, 41.18 g of raw material 2, 2.79 g of tri(dibenzylideneacetone)dipalladium, 28.03 g of potassium carbonate, 1.03 g of tri-tert-butylphosphine and 300 g of toluene were added to the reaction system in sequence, the temperature was raised to 120° C., and the reaction was refluxed for 12 h; after the reaction was completed, the temperature was slightly lowered, diatomaceous earth was used for filtration to remove salt and catalyst, the filtrate was cooled to room temperature, washed three times with water, the organic phase was retained, and the aqueous phase was then extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, spin-dried, and subjected to silica gel column chromatography, with a mixture of petroleum ether and ethyl acetate as an eluent to obtain 38.60 g of intermediate 1.

[0029] Step 2: Under a nitrogen atmosphere, 38.60 g of intermediate 1, 23.46 g of raw material 3, 3.90 g of concentrated sulfuric acid and 400 g of tetrahydrofuran were added to the reaction system in sequence, and the mixture was heated to 85°C and maintained for 6 hours; after the reaction was completed, the mixture was cooled to room temperature, the pH was adjusted to neutral with a 0.1 mol / L sodium bicarbonate aqueous solution, 100 g of water was added, the mixture was shaken, allowed to stand, extracted, and the organic phase was retained. The organic phase was dried over anhydrous magnesium sulfate, spin-dried, and subjected to column chromatography, using a mixture of petroleum ether and ethyl acetate as an eluent to obtain 48.33 g of antioxidant 1.

[0030] Product structure identification: MS of intermediate 1: 486 (MS+H) + ; MS of antioxidant 1: 736 (MS+H) + ; 1HNMR of antioxidant 1-deuterated chloroform- Figure 1: δ 8.26 (d, 2H), 8.00 - 7.84 (m, 3H), 7.78 - 7.64 (m, 3H), 7.58 - 7.43 (m, 2H), 7.23 - 7.07 (m, 2H), 3.94 - 3.85 (m, 9H), 2.64 - 2.51 (m, 4H), 2.54 - 2.46 (m, 3H), 2.14 (d, 3H), 2.00 - 1.83 (m, 2H).

[0031] Synthesis Examples 2 - 5 In Synthesis Examples 2 - 5, antioxidant 2 - antioxidant 5 were synthesized in sequence. Referring to the synthesis method of Synthesis Example 1, raw material 1 was replaced, and the rest was the same as that of Synthesis Example 1. Specifically, the structure of raw material 1, the structures of antioxidant 2 - antioxidant 5, MS (MS + H) + The data is shown in Table 1.

[0032] Table 1. Structures of raw material 1, structures of antioxidant 2 - antioxidant 5, MS (MS + H) involved in Synthesis Examples 2 - 5 + Data.

[0033]

[0034] Example 1 This example provides an environmentally friendly high - strength waterstop and its preparation: An environmentally friendly high - strength waterstop, comprising the following components by mass: 100 parts of ethylene - propylene - diene monomer rubber, 55 parts of reinforcing filler (composed of silica and calcium carbonate with a mass ratio of 1:2), 20 parts of environmentally friendly plasticizer (epoxidized soybean oil), 3 parts of interfacial modifier (γ - aminopropyltriethoxysilane), 2.5 parts of vulcanizing agent (sulfur), 5 parts of activator (zinc oxide), 2 parts of antioxidant (antioxidant 1 prepared in Synthesis Example 1), and 10 parts of flame retardant (aluminum hydroxide).

[0035] Preparation of an environmentally friendly high - strength waterstop: S1: Put ethylene - propylene - diene monomer rubber into a kneader, set the initial temperature at 60 °C, the rotor speed at 50 rpm, and plasticize until the rubber temperature reaches 65 °C. Add silica, calcium carbonate, γ - aminopropyltriethoxysilane, and epoxidized soybean oil, and maintain mixing at 65 °C for 10 minutes to obtain a uniform material A; S2: Heat material A to 90 °C, adjust the rotor speed to 30 rpm, add antioxidant 1 and aluminum hydroxide, and mix for 6 minutes until evenly dispersed to obtain material B; S3: Cool material B to 65 °C, add zinc oxide and sulfur, and mix for 3 minutes until uniform. After sheeting, place it in a nitrogen - protected box and let it stand at room temperature for 24 hours to cure to obtain a pre - vulcanized rubber compound C; S4: Feed the rubber compound C into a screw extruder (barrel temperature: 80 °C) to extrude a strip-shaped blank, then transfer it to a flat vulcanizing machine and vulcanize it at a vulcanizing temperature of 155 °C and a pressure of 12 MPa for 20 minutes to obtain an environmentally friendly high-strength waterstop with a width of 100 mm and a thickness of 10 mm.

[0036] Examples 2 - 5 In Examples 2 - 5, to prepare an environmentally friendly high-strength waterstop, refer to the preparation method of Example 1, and successively replace the antioxidant therein with the antioxidants 2 - 5 prepared in Synthesis Examples 2 - 5, and the rest remains the same as in Example 1.

[0037] Comparative Example 1 For an environmentally friendly high-strength waterstop, refer to the preparation method of Example 1, without adding the antioxidant therein, and the rest remains the same as in Example 1.

[0038] Comparative Example 2 For an environmentally friendly high-strength waterstop, refer to the preparation method of Example 1, and change the mass fraction of ethylene propylene diene monomer rubber therein to 110 parts, and the rest remains the same as in Example 1.

[0039] Comparative Example 3 For an environmentally friendly high-strength waterstop, refer to the preparation method of Example 1, and change the mass fraction of the environmentally friendly plasticizer therein to 5 parts, and the rest remains the same as in Example 1.

[0040] Performance Test: Conduct a performance test experiment on the environmentally friendly high-strength waterstops obtained in the examples and comparative examples. The experiment is carried out according to the method specified in the national standard GB18173.2 - 2014 "Polymer waterproof materials - Part 2: Waterstops", and the test results are shown in Table 2.

[0041] Table 2. Tensile strength, elongation at break, and tear strength data of the environmentally friendly high-strength waterstops obtained in the examples and comparative examples.

[0042]

[0043] All the examples using the anti-aging agent showed balanced high strength and high elasticity, with overall excellent tensile strength, elongation at break, and tear strength, verifying the synergistic improvement effect of the anti-aging agent on the comprehensive properties of the material. Comparative Example 1 (without anti-aging agent) was significantly inferior to the examples in all performance indicators, especially the elongation at break and tear strength decreased significantly, highlighting the decisive influence of the anti-aging agent on the durability and toughness of the material. In Comparative Example 2 (increasing the rubber dosage), although the tensile strength increased slightly, the elongation at break decreased significantly, indicating that excessive rubber would sacrifice the elasticity of the material; in Comparative Example 3 (reducing the plasticizer), the tear strength and elongation at break decreased simultaneously, reflecting that insufficient plasticizer led to embrittlement of the material and weakened the anti-damage ability. In summary, the introduction of the anti-aging agent is the core of performance improvement, and the precise ratio of formulation components (such as the dosage of rubber and plasticizer) is crucial for maintaining the balance between material strength and elasticity. Any imbalance in a single component will lead to performance shortcomings, verifying the necessity of optimizing the formulation in the invention.

[0044] 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, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An environment-friendly high-strength waterstop, characterized in that, It comprises the following components by mass parts: ethylene propylene diene monomer rubber: 100 parts, reinforcing filler: 40 - 70 parts, environment-friendly plasticizer: 10 - 25 parts, interfacial modifier: 1 - 5 parts, vulcanizing agent: 1.5 - 3.5 parts, activator: 3 - 8 parts, antioxidant: 1 - 3 parts, flame retardant: 5 - 15 parts; The antioxidant is the compound shown in Formula 1: Formula 1 The R1 is selected from: methyl, ethyl, propyl, phenyl, methoxy.

2. The environmentally friendly high-strength waterstop according to claim 1, characterized in that, The reinforcing filler is composed of silica and calcium carbonate in a mass part ratio of 1:(1.5 - 2.5).

3. An environmentally friendly high-strength water stop belt according to claim 1, characterized in that, The environment-friendly plasticizer is epoxy soybean oil.

4. An environment-friendly high-strength water stop belt according to claim 1, characterized in that, The interfacial modifier is γ-aminopropyltriethoxysilane; the vulcanizing agent is sulfur.

5. An environmentally friendly high-strength waterstop according to claim 1, characterized in that, The activator is zinc oxide; the flame retardant is aluminum hydroxide.

6. The environmentally friendly high-strength waterstop described in claim 1 is characterized in that, The antioxidant is any one of the compounds shown in the following structures: ； 。 7. A preparation method of an environment-friendly high-strength water stop belt according to any one of claims 1-6, characterized in that, It comprises the following steps: S1. Plasticize the ethylene propylene diene monomer rubber in a Banbury mixer to 60 - 70 °C, add the reinforcing filler, interfacial modifier and environment-friendly plasticizer, and mix for 8 - 12 minutes to obtain Material A; S2. Heat Material A to 85 - 95 °C, add the antioxidant and flame retardant, and mix for 5 - 8 minutes to obtain Material B; S3. Cool Material B to below 70 °C, add the activator and vulcanization system, mix evenly and then take out the sheet to obtain Material C; S4. Mold Material C with an extruder and vulcanize it with a flat vulcanizing machine. The vulcanization temperature is 150 - 160 °C and the time is 15 - 25 minutes to obtain an environment-friendly high-strength waterstop.

8. The preparation method of an environment-friendly high-strength water stop belt according to claim 7, characterized in that, In S1, the rotor speed is controlled at 40 - 60 rpm during the mixing process; In S2, the mixing speed is 25 - 40 rpm.

9. The preparation method of an environment-friendly high-strength water stop belt according to claim 7, characterized in that, After taking out the sheet in S3, it needs to be parked and cured in a nitrogen atmosphere for 24 hours, and then enter S4 for vulcanization and molding.

10. The preparation method of an environment-friendly high-strength water stop belt according to claim 7, characterized in that, The vulcanization pressure is 10 - 15 MPa.

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