Anti-aging pe waterproofing membrane and preparation method thereof

Abstract

This invention discloses an anti-aging PE waterproof membrane and its preparation method, belonging to the technical field of waterproof materials. The PE waterproof membrane is composed of the following components by weight: 10-15 parts by weight of acrylate-modified nano-titanium dioxide-lignin copolymer, 75-90 parts by weight of low-density polyethylene, 0.8-2 parts by weight of crosslinking agent, 0.5-1.5 parts by weight of antioxidant, and 2-4 parts by weight of zinc stearate. The preparation method of this invention results in a PE waterproof membrane with excellent anti-aging and mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of waterproof materials technology, specifically relating to an anti-aging PE waterproof membrane and its preparation method. Background Technology

[0002] Polyethylene waterproof membranes, with their excellent flexibility, reliable waterproofing and sealing properties, and good chemical corrosion resistance, are widely used in the field of building waterproofing. They are effectively adapted to key engineering scenarios such as building roofs, underground structures, municipal roadbeds, and traffic tunnels. By adapting to substrate deformation, blocking water penetration, and resisting the erosion of acids, alkalis, and chemical media, they provide core protection for the durability of engineering structures. However, traditional PE waterproof membranes face significant aging and failure problems during long-term outdoor or complex environmental service. The synergistic effect of ultraviolet rays, high temperatures, and oxygen in the natural environment triggers a series of physicochemical changes within the membrane: ultraviolet rays can penetrate the surface and damage the PE molecular chain structure, leading to chain breakage or cross-linking, causing the membrane to transform from a flexible state to a rigid and brittle state; high temperatures intensify molecular thermal motion, accelerate chain degradation, and lead to a continuous decline in mechanical strength; oxygen induces an oxidation chain reaction, generating aging products such as hydrogen peroxide, causing pores and cracks in the waterproof structure, and a sharp decline in waterproofing performance. The aforementioned aging phenomena not only significantly shorten the service life of PE waterproof membranes, forcing projects to be repaired and replaced in advance, increasing the costs of later maintenance such as membrane procurement, construction scheduling, and removal of old waterproof layers, but may also interfere with the normal use of buildings due to maintenance work, or cause leakage due to untimely repairs, damaging the internal structure and decoration of buildings, posing potential hazards to project quality and safety.

[0003] Patent CN110467769A discloses an antioxidant high-density polyethylene composite material and its preparation method. This invention utilizes a cryogenic pulverization method to obtain high-density polyethylene base material, which is then blended with modified calcium carbonate and surface modifiers. Simultaneously, it is mixed with materials such as P-type carbon black, which have light-shielding and light-absorbing effects, through mechanical blending. This improves the antioxidant properties of the high-density polyethylene material, solves the aging problem of high-density polyethylene material in seawater environment, and extends the service life of high-density polyethylene material.

[0004] Modifying polyethylene materials using inorganic fillers with functions such as shielding ultraviolet light is a relatively simple and low-cost improvement method. However, due to the inertness of the polyethylene material surface, the interfacial compatibility with inorganic fillers is poor, and the aggregation of inorganic fillers can easily lead to uneven dispersion, which can weaken the performance of the improved polyethylene material.

[0005] Therefore, improving the interfacial compatibility between inorganic fillers with functions such as UV resistance and polyethylene materials, and thus achieving improved polyethylene materials with good anti-aging and mechanical properties, has important research and application value. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a PE waterproof membrane that combines anti-aging properties with mechanical strength, thereby solving the technical problems mentioned in the background art. Specifically, the technical solution of this invention includes the following:

[0007] One objective of this invention is to provide an anti-aging PE waterproof membrane, which is composed of the following components in parts by weight:

[0008] 10-15 parts by weight of acrylate-modified nano-titanium dioxide-lignin copolymer, 75-90 parts by weight of low-density polyethylene, 0.8-2 parts by weight of crosslinking agent, 0.5-1.5 parts by weight of antioxidant and 2-4 parts by weight of zinc stearate;

[0009] The preparation method of the acrylate-modified nano-titanium dioxide-lignin copolymer includes the following steps:

[0010] Terephthalic diisocyanate, poly(1,4-butanediol adipate), 1,4-butanediol and dibutyltin dilaurate were mixed in a weight ratio of 6-7:1-2:0.5-0.6:0.005 and stirred at 65-70°C for 3-4 hours to obtain an isocyanate-terminated polyurethane prepolymer mixture.

[0011] Lignin and hydroxyethyl methacrylate were added to the isocyanate-terminated polyurethane prepolymer mixture, and the mixture was heated to 70°C and stirred for 1 hour. Then, titanium dioxide@polyacrylate composite was added and stirred for another hour at 70°C. Finally, the mixture was placed in a mold and cured at 130°C for 4 hours to obtain acrylate-modified nano-titanium dioxide-lignin copolymer.

[0012] Furthermore, the relative density of the low-density polyethylene is 0.918 g / cm³. 3 The melt flow index is 2 g / 10 min.

[0013] Furthermore, the crosslinking agent includes dicumyl peroxide.

[0014] Furthermore, the antioxidant includes antioxidant 1010.

[0015] Furthermore, the molecular weight of the poly(1,4-butanediol adipate) is 2000.

[0016] Furthermore, the preparation method of the titanium dioxide@polyacrylate composite includes the following steps:

[0017] Nano-titanium dioxide, unsaturated silane coupling agent, anhydrous ethanol and water were mixed in a weight ratio of 1:0.08~0.09:80:10 and the pH was adjusted to 4. The mixture was then heated to 50℃~60℃ and stirred for 1 hour to obtain double bond modified nano-titanium dioxide.

[0018] Double-bond modified nano-titanium dioxide, hydroxyethyl acrylate, methyl methacrylate, water, sodium dodecyl sulfate, and ammonium persulfate were mixed in a weight ratio of 1:20~25:55~60:50:1:0.6 and heated to 70℃~75℃ with stirring for 3 hours to obtain a titanium dioxide@polyacrylate composite. The role of the unsaturated silane coupling agent is to graft the silanol groups of the silane coupling agent onto the surface of nano-titanium dioxide, and then introduce the carbon-carbon double bonds of the unsaturated silane coupling agent into the organic polymer structure of polyacrylate. Then, through the condensation reaction of the hydroxyl groups on the polyacrylate with the isocyanate groups, it is introduced into the polyurethane organic structure. With the help of the carbon-carbon double bonds on the polyurethane synthetic monomer hydroxyethyl methacrylate, under the catalysis of the crosslinking agent, the polypropylene material is melt-blended and crosslinked to achieve modification.

[0019] Furthermore, the particle size of the nano-titanium dioxide is 50 nm.

[0020] Furthermore, the unsaturated silane coupling agent includes vinyltriethoxysilane.

[0021] Furthermore, the weight ratio of the isocyanate-terminated polyurethane prepolymer mixture, lignin, hydroxyethyl methacrylate, and titanium dioxide@polyacrylate composite is 1:0.5:0.1:1.

[0022] A second objective of this invention is to provide a method for preparing an anti-aging PE waterproof membrane, the method comprising the following steps:

[0023] Acrylic ester modified nano-titanium dioxide-lignin copolymer and low-density polyethylene are first mixed and kneaded at 100℃ and 60r / min for 3 minutes, then crosslinking agent, antioxidant and zinc stearate are added, and the mixture is kneaded at 130℃ and 60r / min for 10 minutes to obtain a compound. The compound is then subjected to flat vulcanization treatment and calendering treatment to obtain PE waterproof membrane.

[0024] Furthermore, the conditions for the flat plate vulcanization treatment include a temperature of 170°C, a pressure of 15 MPa, and a treatment time of 20 min.

[0025] Furthermore, the calendering conditions include a temperature of 220°C, a pressure of 60 MPa, and a processing time of 2 min.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention first utilizes the silanol groups generated by the hydrolysis of unsaturated silane coupling agents to modify the surface of nano-titanium dioxide, which has anti-UV aging properties. The reactive functional group carbon-carbon double bond of the unsaturated silane coupling agent introduces the inorganic nano-titanium dioxide, which is incompatible with organic materials and has agglomeration properties that affect the modification of polyethylene material performance, into the polyacrylate structure through the polymerization reaction of carbon-carbon double bonds to obtain a titanium dioxide@polyacrylate composite. Next, isocyanate-terminated polyurethane prepolymers were synthesized, then reacted with lignin and hydroxyethyl methacrylate. Finally, titanium dioxide@polyacrylate composites were added and reacted to obtain acrylate-modified nano-titanium dioxide-lignin copolymers. Lignin not only possesses excellent free radical scavenging antioxidant properties, but its benzene ring structure can also mitigate the adverse effects of conventional antioxidants migrating easily and reducing the anti-aging effect of polyethylene materials, thus synergistically improving anti-aging function. The role of hydroxyethyl methacrylate is to achieve high-temperature crosslinking with polyethylene through its carbon-carbon double bonds, thereby grafting it into the polyethylene matrix material and improving the incompatibility defects of direct blending of nano-titanium dioxide with polyethylene, thus achieving modification. The acrylate-modified nano-titanium dioxide-lignin copolymer, low-density polyethylene, crosslinking agents, antioxidants, and other auxiliary materials are blended and crosslinked at high temperature, resulting in a PE waterproof membrane with good anti-aging properties and excellent mechanical properties. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0029] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0030] Preparation Example 1

[0031] The preparation method of titanium dioxide@polyacrylate composite is as follows:

[0032] Weigh 800 parts by weight of anhydrous ethanol and 100 parts by weight of deionized water and add them to a flask. Mix and stir until homogeneous. Then add 0.8 parts by weight of vinyltriethoxysilane and stir until evenly dispersed. Adjust the pH to 4 with dilute hydrochloric acid. Then add 10 parts by weight of nano-titanium dioxide with a particle size of 50 nm and disperse it with ultrasonic power of 200 W for 10 min. Then raise the temperature to 50 °C and stir at 200 r / min for 1 h. After the reaction was completed, the solid particles were collected by filtration, washed successively with anhydrous ethanol and deionized water, and finally dried in a vacuum drying oven at 60°C for 12 hours to obtain double-bond modified nano-titanium dioxide. 50 parts by weight of deionized water, 20 parts by weight of hydroxyethyl acrylate, 55 parts by weight of methyl methacrylate and 1 part by weight of sodium dodecyl sulfate were weighed and mixed and stirred until uniformly dispersed. Then, 0.6 parts by weight of ammonium persulfate and 1 part by weight of double-bond modified nano-titanium dioxide were added and stirred to form a mixed emulsion. The mixed emulsion was heated to 70°C and stirred at 150 r / min for 3 hours to obtain titanium dioxide@polyacrylate composite.

[0033] Preparation Example 2

[0034] The preparation method of titanium dioxide@polyacrylate composite is as follows:

[0035] Weigh 800 parts by weight of anhydrous ethanol and 100 parts by weight of deionized water and add them to a flask. Mix and stir until homogeneous. Then add 0.85 parts by weight of vinyltriethoxysilane and stir until evenly dispersed. Adjust the pH to 4 with dilute hydrochloric acid. Then add 10 parts by weight of nano-titanium dioxide with a particle size of 50 nm and disperse it with ultrasonic power of 200 W for 10 min. Then raise the temperature to 55 °C and stir the reaction at 200 r / min for 1 h. After the reaction was completed, the solid particles were collected by filtration, washed successively with anhydrous ethanol and deionized water, and finally dried in a vacuum drying oven at 60°C for 12 hours to obtain double-bond modified nano-titanium dioxide. 50 parts by weight of deionized water, 23 parts by weight of hydroxyethyl acrylate, 57 parts by weight of methyl methacrylate and 1 part by weight of sodium dodecyl sulfate were weighed and mixed and stirred until uniformly dispersed. Then, 0.6 parts by weight of ammonium persulfate and 1 part by weight of double-bond modified nano-titanium dioxide were added and mixed to form a mixed emulsion. The mixed emulsion was heated to 70°C and stirred at 150 r / min for 3 hours to obtain titanium dioxide@polyacrylate composite.

[0036] Preparation Example 3

[0037] The preparation method of titanium dioxide@polyacrylate composite is as follows:

[0038] Weigh 800 parts by weight of anhydrous ethanol and 100 parts by weight of deionized water and add them to a flask. Mix and stir until homogeneous. Then add 0.9 parts by weight of vinyltriethoxysilane and stir until evenly dispersed. Adjust the pH to 4 with dilute hydrochloric acid. Then add 10 parts by weight of nano-titanium dioxide with a particle size of 50 nm and disperse it with ultrasonic power of 200 W for 10 min. Then raise the temperature to 60 °C and stir at 200 r / min for 1 h. After the reaction was completed, the solid particles were collected by filtration, washed successively with anhydrous ethanol and deionized water, and finally dried in a vacuum drying oven at 60°C for 12 hours to obtain double-bond modified nano-titanium dioxide. 50 parts by weight of deionized water, 25 parts by weight of hydroxyethyl acrylate, 60 parts by weight of methyl methacrylate and 1 part by weight of sodium dodecyl sulfate were weighed and mixed and stirred until uniformly dispersed. Then, 0.6 parts by weight of ammonium persulfate and 1 part by weight of double-bond modified nano-titanium dioxide were added and stirred to form a mixed emulsion. The mixed emulsion was heated to 75°C and stirred at 150 r / min for 3 hours to obtain titanium dioxide@polyacrylate composite.

[0039] Preparation Example 4

[0040] The preparation method of titanium dioxide@polyacrylate composite is as follows:

[0041] Weigh 800 parts by weight of anhydrous ethanol and 100 parts by weight of deionized water and add them to a flask. Mix and stir until homogeneous. Then add 1 part by weight of vinyltriethoxysilane and stir until evenly dispersed. Adjust the pH to 4 with dilute hydrochloric acid. Then add 10 parts by weight of nano-titanium dioxide with a particle size of 50 nm and disperse it using an ultrasonic power of 200 W for 10 min. Then raise the temperature to 70 °C and stir at 200 r / min for 2 h. The rest of the preparation process is the same as in Preparation Example 3.

[0042] Preparation Example 5

[0043] The preparation method of titanium dioxide@polyacrylate composite is as follows:

[0044] The nano-titanium dioxide in Preparation Example 3 was replaced with nano-titanium dioxide with a particle size of 20 nm, and the rest of the preparation process was the same as in Preparation Example 3.

[0045] Preparation Example 6

[0046] The preparation method of titanium dioxide@polyacrylate composite is as follows:

[0047] In Preparation Example 3, the vinyltriethoxysilane was replaced with silane coupling agent KH-550, and the rest of the preparation process was the same as in Preparation Example 3.

[0048] Preparation Example 7

[0049] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0050] First, poly(1,4-butanediol adipate) with a molecular weight of 2000 was dried to remove water for 3 hours under a vacuum of 0.08 MPa and a temperature of 120°C. Then, 12 parts by weight of terephthalic diisocyanate, 2 parts by weight of poly(1,4-butanediol adipate) with a molecular weight of 2000, 1 part by weight of 1,4-butanediol, and 0.01 parts by weight of dibutyltin dilaurate were weighed and mixed in a flask. Nitrogen gas was then introduced to purge the air from the flask, and the mixture was heated to 65°C and stirred at 200 r / min for 3 hours to obtain an isocyanate-terminated polyurethane prepolymer mixture. 0.2 parts by weight of lignin and 0.1 parts by weight of hydroxyethyl methacrylate were pre-dispersed using ultrasonic power at 300 W for 2 hours. After 0 min, 1 part by weight of isocyanate-terminated polyurethane prepolymer mixture was added and mixed. After heating to 70°C, the mixture was stirred at 150 r / min for 1 h. Then, 1 part by weight of the titanium dioxide@polyacrylate composite obtained in Preparation Example 1 was added. The mixture was stirred and reacted for another 1 h at 70°C. After the reaction was completed, the mixture was poured into a mold preheated to 80°C. The mold was then heated to 130°C for 4 h for curing. Finally, the mixture was cooled to room temperature and cured to obtain acrylate-modified nano-titanium dioxide-lignin copolymer.

[0051] Preparation Example 8

[0052] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0053] First, poly(1,4-butanediol adipate) with a molecular weight of 2000 was dried to remove water for 3 hours under a vacuum of 0.08 MPa and a temperature of 120°C. Then, 12 parts by weight of terephthalic diisocyanate, 3 parts by weight of poly(1,4-butanediol adipate) with a molecular weight of 2000, 1.1 parts by weight of 1,4-butanediol, and 0.01 parts by weight of dibutyltin dilaurate were weighed and mixed in a flask. Nitrogen gas was then introduced to purge the air from the flask, and the mixture was heated to 65°C and stirred at 200 r / min for 3.5 hours to obtain an isocyanate-terminated polyurethane prepolymer mixture. 0.2 parts by weight of lignin and 0.1 parts by weight of hydroxyethyl methacrylate were pre-dispersed using an ultrasonic power of 300 W. After 20 minutes of treatment, it was added to 1 part by weight of the isocyanate-terminated polyurethane prepolymer mixture and mixed. After heating to 70°C, it was stirred at 150 r / min for 1 hour. Then, 1 part by weight of the titanium dioxide@polyacrylate composite obtained in Preparation Example 2 was added. The mixture was stirred and reacted for another hour at 70°C. After the reaction was completed, it was poured into a mold preheated to 80°C. The mold was then heated to 130°C for 4 hours and cured. Finally, it was cooled to room temperature to obtain the acrylate-modified nano-titanium dioxide-lignin copolymer.

[0054] Preparation Example 9

[0055] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0056] First, poly(1,4-butanediol adipate) with a molecular weight of 2000 was dried to remove water for 3 hours under a vacuum of 0.08 MPa and a temperature of 120°C. Then, 12 parts by weight of terephthalic diisocyanate, 4 parts by weight of poly(1,4-butanediol adipate) with a molecular weight of 2000, 1.2 parts by weight of 1,4-butanediol, and 0.01 parts by weight of dibutyltin dilaurate were weighed and mixed in a flask. Nitrogen gas was then introduced to purge the air from the flask, and the mixture was heated to 70°C and stirred at 200 r / min for 4 hours to obtain an isocyanate-terminated polyurethane prepolymer mixture. 0.2 parts by weight of lignin and 0.1 parts by weight of hydroxyethyl methacrylate were pre-dispersed using ultrasonic power at 300 W. After 20 minutes, it was added to 1 part by weight of the isocyanate-terminated polyurethane prepolymer mixture and mixed. After heating to 70°C, it was stirred at 150 r / min for 1 hour. Then, 1 part by weight of the titanium dioxide@polyacrylate composite obtained in Preparation Example 3 was added. The mixture was stirred and reacted for another hour at 70°C. After the reaction was completed, it was poured into a mold preheated to 80°C. The mold was then heated to 130°C for 4 hours and cured. Finally, it was cooled to room temperature to obtain the acrylate-modified nano-titanium dioxide-lignin copolymer.

[0057] Preparation Example 10

[0058] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0059] The titanium dioxide@polyacrylate composite in Preparation Example 9 was replaced with the titanium dioxide@polyacrylate composite obtained in Preparation Example 4, and the rest of the preparation process was the same as in Preparation Example 9.

[0060] Preparation Example 11

[0061] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0062] The titanium dioxide@polyacrylate composite in Preparation Example 9 was replaced with the titanium dioxide@polyacrylate composite obtained in Preparation Example 5, and the rest of the preparation process was the same as in Preparation Example 9.

[0063] Preparation Example 12

[0064] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0065] The titanium dioxide@polyacrylate composite in Preparation Example 9 was replaced with the titanium dioxide@polyacrylate composite obtained in Preparation Example 6, and the rest of the preparation process was the same as in Preparation Example 9.

[0066] Preparation Example 13

[0067] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0068] The lignin in Preparation Example 9 was removed and not added, while the rest of the preparation process remained the same as in Preparation Example 9.

[0069] Preparation Example 14

[0070] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0071] The amount of lignin used in Preparation Example 9 was increased to 1 part by weight, while the rest of the preparation process remained the same as in Preparation Example 9.

[0072] Preparation Example 15

[0073] The preparation method of acrylate-modified nano-titanium dioxide-lignin copolymer is as follows:

[0074] The amount of hydroxyethyl methacrylate used in Preparation Example 9 was increased to 1 part by weight, and the rest of the preparation process was the same as in Preparation Example 9.

[0075] Example 1

[0076] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0077] The open mill was preheated to 100°C, and then the speed was adjusted to 60 r / min. Then, 10 parts by weight of the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 7 and 75 parts by weight of a copolymer with a relative density of 0.918 g / cm³ were mixed. 3 Low-density polyethylene with a melt index of 2 g / 10 min was added to a two-roll mill and mixed for 3 min. After the two-roll mill was finished, 0.8 parts by weight of dicumyl peroxide, 0.5 parts by weight of antioxidant 1010 and 2 parts by weight of zinc stearate were added. At this time, the two-roll mill temperature was raised to 130℃, the speed was kept constant, and the two-roll mill was continued for 10 min to obtain a compound. The compound was poured into a flat vulcanizing machine and treated at a vulcanizing temperature of 170℃ and a vulcanizing pressure of 15MPa for 20 min. After the vulcanizing treatment, the obtained polyethylene composite material was calendered by a calender. The temperature during the calendering process was set to 220℃ and the pressure was set to 60MPa. Then, the calender was calendered for 2 min to obtain PE waterproof membrane.

[0078] Example 2

[0079] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0080] The open mill was preheated to 100°C, and then the speed was adjusted to 60 r / min. Then, 12 parts by weight of the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Example 8 and 85 parts by weight of a material with a relative density of 0.918 g / cm³ were mixed. 3 Low-density polyethylene with a melt index of 2 g / 10 min was added to a two-roll mill and mixed for 3 min. After the two-roll mill was finished, 1.5 parts by weight of dicumyl peroxide, 1 part by weight of antioxidant 1010 and 3 parts by weight of zinc stearate were added. At this time, the two-roll mill temperature was raised to 130℃, the speed was kept constant, and the two-roll mill was continued for 10 min to obtain a compound. The compound was poured into a flat vulcanizing machine and treated at a vulcanizing temperature of 170℃ and a vulcanizing pressure of 15MPa for 20 min. After the vulcanizing treatment, the obtained polyethylene composite material was calendered by a calender. The temperature during the calendering process was set to 220℃ and the pressure was set to 60MPa. Then, the calender was calendered for 2 min to obtain PE waterproof membrane.

[0081] Example 3

[0082] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0083] The open mill was preheated to 100°C, and then the speed was adjusted to 60 r / min. Then, 15 parts by weight of the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 9 and 90 parts by weight of a copolymer with a relative density of 0.918 g / cm³ were mixed. 3 Low-density polyethylene with a melt index of 2 g / 10 min was added to a two-roll mill and mixed for 3 min. After the two-roll mill was finished, 2 parts by weight of dicumyl peroxide, 1.5 parts by weight of antioxidant 1010 and 4 parts by weight of zinc stearate were added. At this time, the two-roll mill temperature was raised to 130℃, the speed was kept constant, and the two-roll mill was continued for 10 min to obtain a compound. The compound was poured into a flat vulcanizing machine and treated at a vulcanizing temperature of 170℃ and a vulcanizing pressure of 15MPa for 20 min. After the vulcanizing treatment, the obtained polyethylene composite material was calendered by a calender. The temperature during the calendering process was set to 220℃ and the pressure was set to 60MPa. Then, the calender was calendered for 2 min to obtain PE waterproof membrane.

[0084] Comparative Example 1

[0085] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0086] The acrylate-modified nano-titanium dioxide-lignin copolymer in Example 3 was replaced with the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 10, and the rest of the preparation process was the same as in Example 3.

[0087] Comparative Example 2

[0088] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0089] The acrylate-modified nano-titanium dioxide-lignin copolymer in Example 3 was replaced with the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 11, and the rest of the preparation process was the same as in Example 3.

[0090] Comparative Example 3

[0091] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0092] The acrylate-modified nano-titanium dioxide-lignin copolymer in Example 3 was replaced with the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 12, and the rest of the preparation process was the same as in Example 3.

[0093] Comparative Example 4

[0094] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0095] The acrylate-modified nano-titanium dioxide-lignin copolymer in Example 3 was replaced with the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 13, and the rest of the preparation process was the same as in Example 3.

[0096] Comparative Example 5

[0097] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0098] The acrylate-modified nano-titanium dioxide-lignin copolymer in Example 3 was replaced with the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 14, and the rest of the preparation process was the same as in Example 3.

[0099] Comparative Example 6

[0100] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0101] The acrylate-modified nano-titanium dioxide-lignin copolymer in Example 3 was replaced with the acrylate-modified nano-titanium dioxide-lignin copolymer obtained in Preparation Example 15, and the rest of the preparation process was the same as in Example 3.

[0102] Comparative Example 7

[0103] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0104] The low-density polyethylene in Example 3 was replaced with a polyethylene with a relative density of 0.960 g / cm³. 3 The high-density polyethylene with a melt index of 12 g / 10 min was prepared in the same manner as in Example 3.

[0105] Comparative Example 8

[0106] A method for preparing an anti-aging PE waterproof membrane specifically includes the following steps:

[0107] The acrylate-modified nano-titanium dioxide-lignin copolymer in Example 3 was replaced with nano-titanium dioxide with a particle size of 50 nm, and the rest of the preparation process was the same as in Example 3.

[0108] The anti-aging PE waterproof membranes obtained in Examples 1-3 and Comparative Examples 1-8 were tested respectively, and the test methods are as follows:

[0109] According to Method B in GB / T 328.9-2007, test material specimens were prepared with a thickness controlled at 1.5 mm, and tensile strength was tested. Then, specimens were cut into 220 mm × 25 mm pieces and irradiated with ultraviolet light at a wavelength of 300~400 nm at an intensity controlled at 60 W / m2 for 72 h. After irradiation treatment, tensile strength was tested again according to the above tensile property test method. The results are shown in Table 1 below.

[0110] Table 1 Performance Test Results

[0111]

[0112] The following conclusions can be drawn from the above test results:

[0113] (1) As can be seen from Examples 1 to 3, the PE waterproof membrane prepared by the present invention has good anti-aging and mechanical properties.

[0114] (2) Comparative Example 1 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because when vinyltriethoxysilane is used to modify nano-titanium dioxide in this system, the amount of vinyltriethoxysilane is too large, the modification temperature is too high and the time is too long. It may be due to the polycondensation reaction of vinyltriethoxysilane itself to form polysiloxane, which affects the surface modification of nano-titanium dioxide and is not conducive to the dispersion of nano-titanium dioxide, thus resulting in poor performance of the PE waterproof membrane prepared in the end.

[0115] (3) Comparative Example 2 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because when the particle size of nano titanium dioxide is too small in this system, the surface energy of nano titanium dioxide is too high, and the agglomeration is more serious. As a result, it is difficult to achieve uniform dispersion of nano titanium dioxide under the surface modification method of this system, which leads to poor performance of the PE waterproof membrane finally prepared.

[0116] (4) Comparative Example 3 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because, although the silane coupling agent KH-550 can modify nano titanium dioxide through silanol, the lack of carbon-carbon double bonds means that the titanium dioxide modified by the silane coupling agent cannot be introduced into polyacrylate through carbon-carbon double bond grafting. As a result, it cannot achieve good mixing modification with polyethylene material through polymerization crosslinking, which leads to poor performance of the PE waterproof membrane prepared in the end.

[0117] (5) Comparative Example 4 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because the synergistic improvement effect of lignin is lacking in this system. Relying solely on nano-titanium dioxide and antioxidants, the antioxidants may have poor anti-oxidation effect due to migration, and the improvement effect of nano-titanium dioxide may be weak under the usage of this system, thus resulting in poor performance of the PE waterproof membrane prepared in the end.

[0118] (6) Comparative Example 5 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because although lignin can synergistically improve anti-aging performance in this system, due to the large number of benzene ring structures in lignin itself, excessive use in this system may lead to excessive rigidity of the material, easy cracking, and thus poor performance of the PE waterproof membrane prepared in the end.

[0119] (7) Comparative Example 6 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because, although the role of hydroxyethyl methacrylate in this system is to achieve high-temperature cross-linking with polyethylene through carbon-carbon double bonds in the structure, and then graft it into the polyethylene matrix material, the amount used is too high, which can easily lead to excessive consumption of isocyanate groups. This may make it difficult for the titanium dioxide@polyacrylate composite to react with isocyanate groups through hydroxyl groups, resulting in poor cross-linking effect when blended with polyethylene matrix material, and thus the performance of the PE waterproof membrane prepared in the end is not good.

[0120] (8) Comparative Example 7 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because high-density polyethylene has poor melt flow due to its high crystallinity. In the preparation method of this system, it is difficult to effectively blend and modify it, which leads to poor performance of the PE waterproof membrane finally prepared.

[0121] (9) Comparative Example 8 shows that the PE waterproof membrane prepared has poor anti-aging performance and mechanical properties. This may be because the unmodified nano titanium dioxide was directly added to modify the polyethylene material. Due to interfacial incompatibility and agglomeration, the modification effect was poor.

[0122] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. An anti-aging PE waterproof membrane, characterized in that, The PE waterproof membrane is composed of the following components in parts by weight: 10-15 parts by weight of acrylate-modified nano-titanium dioxide-lignin copolymer, 75-90 parts by weight of low-density polyethylene, 0.8-2 parts by weight of crosslinking agent, 0.5-1.5 parts by weight of antioxidant and 2-4 parts by weight of zinc stearate; The preparation method of the acrylate-modified nano-titanium dioxide-lignin copolymer includes the following steps: Terephthalic diisocyanate, poly(1,4-butanediol adipate), 1,4-butanediol and dibutyltin dilaurate were mixed in a weight ratio of 6-7:1-2:0.5-0.6:0.005 and stirred at 65-70°C for 3-4 hours to obtain an isocyanate-terminated polyurethane prepolymer mixture. Lignin and hydroxyethyl methacrylate were added to the isocyanate-terminated polyurethane prepolymer mixture, and the mixture was heated to 70°C and stirred for 1 hour. Then, titanium dioxide@polyacrylate composite was added and stirred for another hour at 70°C. Finally, the mixture was placed in a mold and cured at 130°C for 4 hours to obtain acrylate-modified nano-titanium dioxide-lignin copolymer. The preparation method of titanium dioxide@polyacrylate composite includes the following steps: Nano-titanium dioxide, unsaturated silane coupling agent, anhydrous ethanol and water were mixed in a weight ratio of 1:0.08~0.09:80:10 and the pH was adjusted to 4. The mixture was then heated to 50℃~60℃ and stirred for 1 hour to obtain double bond modified nano-titanium dioxide. Double bond modified nano-titanium dioxide, hydroxyethyl acrylate, methyl methacrylate, water, sodium dodecyl sulfate and ammonium persulfate were mixed in a weight ratio of 1:20~25:55~60:50:1:0.6 and heated to 70℃~75℃ and stirred for 3h to obtain titanium dioxide@polyacrylate composite. The weight ratio of the isocyanate-terminated polyurethane prepolymer mixture, lignin, hydroxyethyl methacrylate, and titanium dioxide@polyacrylate composite is 1:0.2:0.1:

1.

2. The anti-aging PE waterproof membrane according to claim 1, characterized in that, The relative density of the low-density polyethylene is 0.918 g / cm³. 3 The melt flow index is 2 g / 10 min.

3. The anti-aging PE waterproof membrane according to claim 1, characterized in that, The crosslinking agent includes dicumyl peroxide.

4. The anti-aging PE waterproof membrane according to claim 1, characterized in that, The antioxidant includes antioxidant 1010.

5. The anti-aging PE waterproof membrane according to claim 1, characterized in that, The molecular weight of the poly(1,4-butanediol adipate) is 2000.

6. The anti-aging PE waterproof membrane according to claim 1, characterized in that, The nano-titanium dioxide has a particle size of 50 nm.

7. The anti-aging PE waterproof membrane according to claim 1, characterized in that, The unsaturated silane coupling agent includes vinyltriethoxysilane.

8. A method for preparing an anti-aging PE waterproof membrane as described in any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: Acrylic ester modified nano-titanium dioxide-lignin copolymer and low-density polyethylene are first mixed and kneaded at 100℃ and 60r / min for 3 minutes, then crosslinking agent, antioxidant and zinc stearate are added, and the mixture is kneaded at 130℃ and 60r / min for 10 minutes to obtain a compound. The compound is then subjected to flat vulcanization treatment and calendering treatment to obtain PE waterproof membrane.

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