Light-resistant and flame-retardant thermoplastic polyolefin waterproof roll and preparation method thereof

Abstract

This application discloses a light-resistant, flame-retardant thermoplastic polyolefin waterproofing membrane and its preparation method. The light-resistant, flame-retardant thermoplastic polyolefin waterproofing membrane comprises, by weight: 60-80 parts of a thermoplastic polyolefin elastomer; 5-20 parts of a plastomer; 10-40 parts of a flame retardant; 2-10 parts of a light stabilizer; 1-5 parts of a compatibilizer; and 1-5 parts of an additive. The flame retardant and light stabilizer both comprise modified lignin, the surface of which is grafted with a titanate coupling agent, and the D50 of the modified lignin is 5.0-8.0 nm. According to embodiments of the present application, the light stability and flame retardancy of the TPO waterproofing membrane can be improved.

Description

Technical Field

[0001] The present application relates to a waterproof roll material, and in particular to a light-resistant, flame-retardant thermoplastic polyolefin waterproof roll material and a preparation method thereof. Background Art

[0002] Thermoplastic polyolefin (TPO), a new material that has garnered widespread attention in the waterproofing industry in recent years, is a copolymer based on ethylene and propylene. Due to its saturated molecular chain, relatively low tertiary carbon atom content, and lack of polar atoms, TPO possesses chemical stability. Furthermore, this material combines the excellent processing properties of plastic with the toughness of rubber, boasting low density and excellent low-temperature toughness. Furthermore, it can be processed using conventional equipment, making it a promising new material.

[0003] However, with the continuous development of the market and the implementation of the "GB 55030-2022 General Specification for Waterproofing of Buildings and Municipal Engineering," higher requirements have been placed on various indicators of waterproof membranes, including durability and flame retardancy. TPO waterproof membranes used in outdoor waterproofing scenarios are subject to long-term exposure to sunlight. Therefore, to better ensure the durability of waterproofing projects, it is necessary to improve the light stability and flame retardancy of TPO waterproof membranes. Furthermore, dimensional stability is also a very important indicator for waterproof membranes used in outdoor welding construction. Summary of the Invention

[0004] The embodiments of the present application provide a light-resistant and flame-retardant thermoplastic polyolefin waterproof membrane and a preparation method thereof, which can improve the light stability and flame retardancy of the TPO waterproof membrane.

[0005] In the first aspect, the embodiment of the present application provides a light-resistant and flame-retardant thermoplastic polyolefin waterproof membrane, which includes, by weight: 60 to 80 parts of a thermoplastic polyolefin elastomer; 5 to 20 parts of a plastomer; 10 to 40 parts of a flame retardant; 2 to 10 parts of a light stabilizer; 1 to 5 parts of a compatibilizer; and 1 to 5 parts of an additive; wherein the flame retardant and the light stabilizer both include modified lignin, the surface of the modified lignin is grafted with a titanate coupling agent, and the D50 of the modified lignin is 5.0 to 8.0 nm.

[0006] In any embodiment of the present application, the flame retardant includes magnesium hydroxide and modified lignin, wherein the weight ratio of magnesium hydroxide to modified lignin is 2:1 to 5:1.

[0007] In any embodiment of the present application, the light stabilizer includes modified lignin and titanium dioxide, wherein the weight ratio of the modified lignin to titanium dioxide is 3:1 to 10:1.

[0008] In any embodiment of the present application, the plastomer includes at least one of high density polyethylene, homopolypropylene, segmented polypropylene, and linear low density polyethylene.

[0009] In any embodiment of the present application, the compatibilizer includes at least one of PP-g-MAH, PP-g-GMA, and PE-g-MAH.

[0010] In any embodiment of the present application, the additives include an antioxidant and a masterbatch, wherein the weight portion of the antioxidant is 0.1 to 1 part, and the weight portion of the masterbatch is 1 to 4 parts.

[0011] In any embodiment of the present application, the titanate coupling agent includes at least one of isopropyl triisostearate titanate, diisopropyl di(triethylamine) titanate, and tetraisopropyl di(dioctylphosphite) titanate.

[0012] In the second aspect, an embodiment of the present application provides a method for preparing a plastic polyolefin waterproof membrane, comprising: mixing materials containing a thermoplastic polyolefin elastomer, a plastomer, a flame retardant, a light stabilizer, a compatibilizer and additives according to a preset ratio, and then conveying the materials to an extruder, and obtaining a plastic polyolefin waterproof membrane through extrusion molding, calendering, pulling and winding processes; wherein the flame retardant and the light stabilizer both include modified lignin.

[0013] In any embodiment of the present application, the method for preparing the modified lignin includes: ball milling a material containing lignin and a titanate coupling agent to obtain the modified lignin.

[0014] In any embodiment of the present application, the mass ratio of lignin to titanate coupling agent is 10:1 to 200:1.

[0015] In any embodiment of the present application, the rotation speed during ball milling is 300 to 1000 rpm, and the time is 1 to 3 hours.

[0016] The light-aging-resistant, flame-retardant thermoplastic polyolefin waterproofing membrane and its preparation method according to the present invention simultaneously improve the membrane's strength, light stability, and flame retardancy by introducing modified lignin into the membrane's components. Furthermore, by adjusting the particle size of the modified lignin and increasing its specific surface area, the modified lignin's surface can be grafted with more coupling agent groups, thereby enhancing the interaction between the modified lignin and the membrane's substrate and improving its dispersibility. Furthermore, the coupling agent groups and the compatibilizer groups connect through hydrogen bonds or other electrostatic forces, allowing the modified lignin to be more firmly and evenly dispersed within the membrane's substrate, further enhancing the membrane's strength, light stability, and flame retardancy. DETAILED DESCRIPTION

[0017] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present application may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present application, rather than all of the embodiments.

[0019] The "ranges" disclosed herein are defined in terms of lower and upper limits, where a given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner can be inclusive or exclusive of the end values and can be combined arbitrarily, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise indicated, the numerical range "a to b" is a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0020] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0021] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of this application.

[0022] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0023] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0024] Unless otherwise specified, this application adopts conventional test methods or test methods recommended by the instrument.

[0025] To reduce production costs, most manufacturers in the industry currently increase production speeds. However, this often results in significant residual stress within the product, leading to significant dimensional changes after a 24-hour heat treatment. This can easily cause weld edges to break off during long-term outdoor use, creating leaks that are detrimental to the durability of outdoor waterproofing projects.

[0026] Existing technologies improve TPO's flame retardancy and light stability by adding flame retardants and light stabilizers, respectively. Flame retardants include common halogen flame retardants, phosphorus-based flame retardants, and metal hydroxide flame retardants, while light stabilizers include titanium dioxide, carbon black, and hindered phenols. When designing a product formula, it often requires two or three main components and four or five additives with different functions. This makes the overall formula extremely complex and can also lead to compatibility issues between the different components.

[0027] Lignin is a material that has attracted considerable attention in recent years. Its unique "hindered phenol" structure and its microstructure composed of multiple benzene rings give it hard and strong properties. These characteristics give lignin great potential in the field of modified plastics. However, for the modification of weakly polar matrices such as polyolefins and thermoplastic polyolefin elastomers, there is still the challenge of how to improve the interfacial tension between lignin and the matrix resin. Currently, the following technical approaches are mainly adopted:

[0028] (1) Using solution method or sol-gel method to modify the surface of lignin, reduce the polarity of lignin, or increase the active groups to enhance the interfacial bonding force between lignin and resin matrix.

[0029] (2) Adding a compatibilizer to the matrix can enhance the compatibility between lignin and the matrix, thereby improving the dispersion of lignin in the matrix.

[0030] However, there are three risks in surface modification of lignin using solution method or sol-gel method: ① The reaction controllability is relatively poor, and there are many side reactions, resulting in poor modification effect; ② In order to ensure the modification effect, high requirements are placed on the purification process.

[0031] In order to solve the problems existing in the prior art and give full play to the various modification effects of lignin in polyolefin materials, this application adopts particle size refinement + surface modification + compatibilizer, and through the synergistic effect of the three, fully improves the interfacial bonding force between modified lignin and thermoplastic polyolefin.

[0032] Thermoplastic polyolefin waterproof membrane

[0033] A light-aging-resistant and flame-retardant thermoplastic polyolefin waterproof membrane comprises, by weight, 60 to 80 parts of a thermoplastic polyolefin elastomer; 5 to 20 parts of a plastomer; 10 to 40 parts of a flame retardant; 2 to 10 parts of a light stabilizer; 1 to 5 parts of a compatibilizer; and 1 to 5 parts of an additive. The flame retardant and the light stabilizer both comprise modified lignin, a titanate coupling agent being grafted onto the surface of the modified lignin, and the D50 of the modified lignin is 5.0 to 8.0 nm.

[0034] This application simultaneously improves the strength, light stability, and flame retardancy of waterproofing membranes by incorporating modified lignin into their composition. The modified lignin's refined particle size increases its specific surface area, allowing for the grafting of more coupling agent groups onto its surface. This in turn enhances the interaction between the modified lignin and the membrane matrix, improving its dispersibility. Furthermore, the coupling agent groups connect with the compatibilizer groups through hydrogen bonds or other electrostatic forces, allowing the modified lignin to be more firmly and evenly dispersed within the membrane matrix, further enhancing the membrane's strength, light stability, and flame retardancy. Furthermore, the combined effects of the overall formulation further enhance the membrane's strength, light stability, and flame retardancy.

[0035] The modified lignin molecules disclosed in the present application contain a large number of aromatic groups, phenolic hydroxyl groups, alcoholic hydroxyl groups and other groups, which can form a carbon layer protective layer on the surface of the waterproof coiled material during combustion, thereby achieving a flame retardant effect.

[0036] In some embodiments, the flame retardant comprises magnesium hydroxide and modified lignin, wherein the weight ratio of magnesium hydroxide to modified lignin is 2:1 to 5:1. Alternatively, the weight ratio of magnesium hydroxide to modified lignin is independently selected from any of 2.0:1, 2.5:1, 3.0:1, 3.6:1, 4.0:1, 4.5:1, and 5.0:1, or any range therebetween. Within this range, the flame retardant effect of the flame retardant can be further enhanced.

[0037] In some embodiments, the D50 of the magnesium hydroxide is between 0.5 and 2 μm, and the magnesium hydroxide with a particle size less than or equal to 2 μm accounts for 50% to 70% of the total magnesium hydroxide.

[0038] In some embodiments, the light stabilizer comprises modified lignin and titanium dioxide, wherein the weight ratio of the modified lignin to titanium dioxide is 3:1 to 10:1. Alternatively, the weight ratio of the modified lignin to titanium dioxide is independently selected from any of 3.0:1, 3.5:1, 4.0:1, 4.5:1, 5.0:1, 5.5:1, 6.0:1, 6.5:1, 7.0:1, 7.5:1, 8.0:1, 8.5:1, 9.0:1, 9.5:1, and 10.0:1, or any range therebetween. Within this range, the light aging resistance of the light stabilizer can be further enhanced.

[0039] In some embodiments, the plastomer comprises at least one of high-density polyethylene (HDPE), homopolypropylene (PPH), segmented polypropylene (PPB), and linear low-density polyethylene (LLDPE). High-density polyethylene refers to polyethylene with a density of 0.941 to 0.960 g / cm3, and linear low-density polyethylene refers to polyethylene with a density of 0.918 to 0.935 g / cm3. 3 As an example, high-density polyethylene can be 0.95 g / cm3. Linear low-density polyethylene can be 0.92 g / cm3. Homopolymer polypropylene can be 0.909 g / cm3. Block polypropylene can be 0.892 g / cm3.

[0040] In some embodiments, the compatibilizer includes at least one of PP-g-MAH, PP-g-GMA, and PE-g-MAH. Within this range, the interfacial bonding between magnesium hydroxide and other components of the waterproofing membrane can be significantly improved. Furthermore, due to the presence of numerous oxygen-containing groups in the compatibilizer and modified lignin, a certain degree of hydrogen bonding or other types of electrostatic forces are generated when the two are mixed, thereby enhancing the dispersibility of the modified lignin.

[0041] In some embodiments, the additive includes an antioxidant and a masterbatch, wherein the antioxidant is present in an amount of 0.1 to 1 parts by weight and the masterbatch is present in an amount of 1 to 4 parts by weight. Optionally, the antioxidant may be at least one of Irgafos 1010, 2,6-di-tert-butyl-p-cresol, and Irgafos 168.

[0042] In some embodiments, the titanate coupling agent includes at least one of isopropyl triisostearate titanate, diisopropyl di(triethylamine) titanate, and tetraisopropyl di(dioctylphosphite) titanate.

[0043] Preparation method

[0044] A method for preparing a plastic polyolefin waterproof roll comprises: mixing materials containing a thermoplastic polyolefin elastomer, a plastomer, a flame retardant, a light stabilizer, a compatibilizer and an additive according to a preset ratio, conveying the materials to an extruder, and obtaining the plastic polyolefin waterproof roll through extrusion molding, calendering, pulling and winding processes; wherein the flame retardant and the light stabilizer both comprise modified lignin.

[0045] In the present application, the extrusion molding conditions may be: an extruder temperature of 145-210° C., a screw speed of 10-40 rpm, and the calendering, pulling, and winding process conditions may be: a line speed of 3-6 m / min.

[0046] In some embodiments, the preparation method of modified lignin includes: ball milling a material containing lignin and a titanate coupling agent to obtain modified lignin.

[0047] In this application, prior to modification, the lignin may be dried to enhance the surface modification effect and allow more coupling agents to be grafted onto the lignin surface. The drying conditions are not specifically limited and can be adjusted as needed by those skilled in the art. As an example, the drying temperature may be 80-120°C for 4-8 hours.

[0048] This application utilizes mechanical activation combined with solid-phase reaction to modify lignin. Mechanical activation can reduce lignin particle size and increase the specific surface area of the lignin raw material. Using solid-phase reaction can effectively simplify the reaction process, enhance the lignin surface modification effect, and effectively reduce the probability of side reactions.

[0049] In some embodiments, the mass ratio of lignin to titanate coupling agent is 10: 1 to 200: 1. Alternatively, the mass ratio of lignin to titanate coupling agent is independently selected from any value of 10: 1, 20: 1, 30: 1, 40: 1, 50: 1, 60: 1, 70: 1, 80: 1, 90: 1, 100: 1, 110: 1, 120: 1, 130: 1, 140: 1, 150: 1, 160: 1, 170: 1, 180: 1, 190: 1, 200: 1, or any range therebetween.

[0050] In some embodiments, the ball milling process is performed at a rotational speed of 300 to 1000 rpm for a time of 1 to 3 hours. Alternatively, the ball milling process is performed at a rotational speed independently selected from any value of 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, or 1000 rpm, or a range thereof. Alternatively, the ball milling process is performed at a rotational speed independently selected from any value of 1.0 h, 1.5 h, 2.0 h, 2.5 h, or 3.0 h, or a range thereof.

[0051] During ball milling, 400 to 800 g of high chromium cast balls or zirconia balls with a diameter of 5 to 15 mm can be added to the ball mill.

[0052] The proportions of different embodiments and comparative examples are shown in Table 1.

[0053] Table 1 Proportions of different embodiments and comparative examples (unit: parts by weight)

[0054]

[0055] Table 2 Proportions of different embodiments and comparative examples (unit: parts by weight)

[0056]

[0057]

[0058] In Table 1, the D50 of magnesium hydroxide 1 is between 0.5 and 2 μm, and the magnesium hydroxide with a particle size less than or equal to 2 μm accounts for 64% of the total magnesium hydroxide.

[0059] The D50 of magnesium hydroxide 2 is 5 to 8 μm, and the magnesium hydroxide with a particle size less than or equal to 2 μm accounts for 25% of the total magnesium hydroxide.

[0060] Example 1

[0061] 1. Preparation of modified lignin

[0062] Place the lignin in an oven and dry it at 80°C for 4 hours. Then, weigh 20g of lignin and 0.4g of diisopropyl di(triethylamine)titanate (2% by weight of the lignin) and place them in a ball mill. Add 400g of 5mm diameter zirconium oxide balls and adjust the ball mill speed to 300rpm. After mechanical activation for 1 hour, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0063] 2. Preparation of thermoplastic polyolefin waterproof membrane

[0064] The corresponding materials were weighed according to the ratio in Table 1, added into a high-speed mixer, stirred at room temperature, and then extruded at an extrusion temperature of 150-170°C and a screw speed of 10 rpm. The thermoplastic polyolefin waterproof membrane was obtained through calendering, pulling, and winding processes at a line speed of 6 m / min.

[0065] Example 2

[0066] 1. Preparation of modified lignin

[0067] Place the lignin in an oven and dry it at 100°C for 5 hours. Then, weigh 30g of lignin and 0.9g of isopropyl titanate triisostearate (3% by weight of the lignin) and place them in a ball mill. Add 500g of 8mm diameter zirconium oxide balls and adjust the ball mill speed to 500rpm. After mechanical activation for 2 hours, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0068] 2. Preparation of thermoplastic polyolefin waterproof membrane

[0069] The corresponding materials were weighed according to the ratio in Table 1, added into a high-speed mixer, stirred at room temperature, and then extruded at an extruder temperature of 175-195° C. and a screw speed of 25 rpm. The thermoplastic polyolefin waterproof membrane was obtained through calendering, pulling, and winding processes at a line speed of 3.5 m / min.

[0070] Example 3

[0071] 1. Preparation of modified lignin

[0072] Place the lignin in an oven and dry it at 110°C for 6 hours. Then, weigh 35g of lignin and 0.8g of isopropyl titanate triisostearate (the titanate coupling agent accounts for 2.29% of the lignin mass) and place them in a ball mill. Add 600g of 12mm diameter high-chromium cast balls and adjust the ball mill speed to 600rpm. After mechanical activation for 3 hours, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0073] 2. Preparation of thermoplastic polyolefin waterproof membrane

[0074] The corresponding materials were weighed according to the ratio in Table 1, added into a high-speed mixer, stirred at room temperature, and then extruded at an extruder temperature of 185-205°C and a screw speed of 25 rpm. The thermoplastic polyolefin waterproof membrane was obtained through calendering, pulling, and winding processes at a line speed of 6 m / min.

[0075] Example 4

[0076] 1. Preparation of modified lignin

[0077] Place the lignin in an oven and dry it at 90°C for 8 hours. Then, weigh 40g of lignin and 1g of tetraisopropyl di(dioctylphosphite) titanate (the titanate coupling agent accounts for 2.5% of the lignin mass) and place them in a ball mill. Add 800g of 15mm diameter high-chromium cast balls and adjust the ball mill speed to 1000rpm. After mechanical activation for 3 hours, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0078] 2. Preparation of thermoplastic polyolefin waterproof membrane

[0079] The corresponding materials were weighed according to the ratio in Table 1, added into a high-speed mixer, stirred at room temperature, and then extruded at an extruder temperature of 195-210°C and a screw speed of 35 rpm. The thermoplastic polyolefin waterproof membrane was obtained through calendering, pulling, and winding processes at a line speed of 4 m / min.

[0080] Example 5

[0081] 1. Preparation of modified lignin

[0082] Place the lignin in an oven and dry it at 100°C for 5 hours. Then, weigh 30g of lignin and 1.2g of isopropyl titanate triisostearate (4% by weight of the lignin) and place them in a ball mill. Add 500g of 8mm diameter zirconium oxide balls and adjust the ball mill speed to 500rpm. After mechanical activation for 2 hours, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0083] 2. Preparation of thermoplastic polyolefin waterproof membrane

[0084] The corresponding materials were weighed according to the ratio in Table 1, added into a high-speed mixer, stirred at room temperature, and then extruded at an extruder temperature of 175-195° C. and a screw speed of 25 rpm. The thermoplastic polyolefin waterproof membrane was obtained through calendering, pulling, and winding processes at a line speed of 3.5 m / min.

[0085] Example 6

[0086] The preparation method of the modified lignin and the preparation method of the thermoplastic polyolefin waterproof membrane are consistent with those in Example 2, and the preparation is carried out according to the ratio in Table 1. The compatibilizer is PP-g-MAH.

[0087] Example 7

[0088] The preparation method of the modified lignin and the preparation method of the thermoplastic polyolefin waterproof membrane are consistent with those in Example 2, and the preparation is carried out according to the ratio in Table 1. The compatibilizer is PE-g-MAH.

[0089] Example 8

[0090] The preparation method of the modified lignin and the preparation method of the thermoplastic polyolefin waterproof membrane are consistent with those in Example 2, and the preparation ratios are according to Table 1, except that the type of magnesium hydroxide is changed from magnesium hydroxide 1 to magnesium hydroxide 2.

[0091] Examples 9-11

[0092] The experimental steps and raw material ratios of Examples 9-11 are basically the same as those of Example 2, with the only difference being the mass ratio of lignin to coupling agent in step 1.

[0093] Example 9: Place the lignin in an oven and dry it at 100°C for 5 hours. Then, weigh 30g of lignin and 0.3g of isopropyl titanate triisostearate (1% of the lignin mass) and place them in a ball mill. Add 500g of 8mm diameter zirconium oxide balls and adjust the ball mill speed to 500rpm. After mechanical activation for 2 hours, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0094] Example 10: Place the lignin in an oven and dry it at 100°C for 5 hours. Then, weigh 30g of lignin and 0.6g of isopropyl titanate triisostearate (2% by weight of the lignin) and place them in a ball mill. Add 500g of 8mm diameter zirconium oxide balls and adjust the ball mill speed to 500rpm. After mechanical activation for 2 hours, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0095] Example 11: Place the lignin in an oven and dry it at 100°C for 5 hours. Then, weigh 30g of lignin and 1.5g of isopropyl titanate triisostearate (5% by weight of the lignin) and place them in a ball mill. Add 500g of 8mm diameter zirconium oxide balls and adjust the ball mill speed to 500rpm. After mechanical activation for 2 hours, separate the balls and the material to obtain the modified lignin. Finally, place it in a desiccator and set aside.

[0096] Comparative Examples 1-5

[0097] The corresponding materials were weighed according to the corresponding ratios in Table 1, added to a high-speed mixer, and stirred at room temperature. Subsequently, the materials were extruded at an extruder temperature of 175-195°C and a screw speed of 25 rpm. The waterproof membrane was obtained through calendering, pulling, and winding at a linear speed of 3.5 m / min.

[0098] in:

[0099] The preparation methods of mechanically ground lignin, titanate coupling agent solution modified lignin and sol-gel modified lignin in Table 1 are as follows:

[0100] 1. The preparation of mechanically ground lignin is as follows:

[0101] Place the lignin in an oven and dry it at 100°C for 5 hours. Then, weigh 30g of lignin and place it in a ball mill. Add 500g of 8mm diameter zirconium oxide balls and adjust the ball mill speed to 500rpm. After mechanical activation for 2 hours, separate the balls and the material to obtain mechanically ground lignin. Finally, place it in a desiccator and set aside.

[0102] 2. The preparation of titanate coupling agent solution modified lignin is as follows:

[0103] 2 wt% (based on the lignin content) of titanate coupling agent was weighed and added to a 50 ml beaker. The mixture was stirred at room temperature and 300 rpm. A certain amount of 70% ethanol solution was added. The pH value of the system was adjusted to 4-5 with 5% acetic acid solution. The mixture was stirred for 2 h to obtain a hydrolyzate.

[0104] 100 g of lignin powder was loaded into a grinder and processed at a speed of 25,000 rpm for 15 minutes to obtain refined lignin powder. The powder was then added to a hydrolyzate and reacted at 50°C and 1,000 rpm for 30 minutes. The precipitate was then separated by a high-speed centrifuge at 10,000 rpm to obtain a precipitate. The precipitate was then washed with deionized water for 3 to 5 times and vacuum dried at 100°C for 6 hours to obtain titanate coupling agent solution-modified lignin.

[0105] 3. Preparation of sol-gel modified lignin is as follows:

[0106] Preparation of SiO2 modified lignin by sol-gel method:

[0107] 30 ml of H2O, 90 ml of ethanol, and 1 g of dodecylphenol polyoxyethylene ether (OP-10) were added to a three-necked flask and magnetically stirred in a 30°C constant temperature water bath for 15 minutes. 10 g of lignin was then added and stirred for another 15 minutes to form a brown suspension. The pH of the suspension was then adjusted to 3-4 with HCl, and 5 g of tetraethoxysilane (TEOS) was slowly added to the suspension. The mixture was reacted in a 40°C constant temperature water bath for 24 hours. Finally, the resulting suspension was centrifuged at 4000 rpm for 2 minutes to obtain a precipitate, which was then repeatedly washed with ethanol. After multiple operations, the final product was obtained and dried at 60°C for 12 hours to obtain the sol-gel modified lignin.

[0108] Test results

[0109] The waterproof membranes of Examples 1-11 and Comparative Examples 1-5 were tested using the following test methods:

[0110] The light aging resistance of the sample is characterized by the retention rate of tensile strength before and after 7 days of UV treatment.

[0111] The initial thermal weight loss (degradation) temperature of the sample was characterized by thermal weight loss test. The temperature T corresponding to the weight loss of 5% of the sample was used. 5％ The flame retardancy of the sample is characterized by the high or low temperature. The test conditions are air atmosphere, heating rate of 10K / min, and heating range from room temperature to 600℃.

[0112] Conventional mechanical properties tests were conducted in accordance with GB / T 27789-2011, and the test items included tensile strength and elongation at break.

[0113] The test results are shown in Table 3:

[0114] Table 3 Test results of different samples

[0115]

[0116] The key to this application is to use ball milling to refine lignin, and then use titanate coupling agent to modify the surface of lignin under high temperature and in the absence of solvent, under the action of a compatibilizer, to improve the dispersion of lignin and magnesium hydroxide in the matrix, thereby achieving better flame retardant effect and light stability effect, while improving mechanical properties.

[0117] It can be seen from Example 2 and Examples 9-11 that as the amount of coupling agent added continues to increase, the difference in tensile strength is not much, the elongation at break is also increasing, and the light stability and flame retardant properties are improved to a certain extent. This is mainly because the final amount of lignin added remains consistent, and the overall strength gap is not too large. As the amount of coupling agent added continues to increase, the dispersibility of lignin is also continuously improved, and the elongation, light stability and flame retardant properties are all improved. From the results in Table 3, it can be seen that when the mass percentage of the coupling agent is increased from 1% to 3%, the elongation at break is significantly improved. However, when it is increased from 3% to 5%, the elongation, light stability and flame retardant properties will not be greatly improved, which shows that when the amount of coupling agent added is increased from 3% to 5%, the improvement effect on the dispersibility of lignin is already negligible. Therefore, in this application, the modification effect on lignin is best when the coupling agent accounts for 3% of the mass of lignin.

[0118] In the examples, the D50 of lignin gradually decreased with increasing ball milling time. However, actual data shows that smaller lignin particle size is not necessarily better. When the D50 is 6.65μm, the modification effect is far superior to lignin with a particle size of 5.56μm and 4.78μm. In terms of flame retardancy, flame retardancy improves with increasing the total amount of magnesium hydroxide and lignin added. In terms of photoaging, the photoaging performance retention rate also increases with increasing the amount of modified lignin and titanium dioxide added. Because the modified lignin has the highest proportion in Example 5, it performs very well in terms of photoaging performance retention. It is worth noting that compared to Example 2, since Example 5 does not contain magnesium hydroxide and relies solely on modified lignin as a flame retardant, the flame retardant effect is relatively poor. This is mainly because the thermal decomposition point of magnesium hydroxide is around 350°C, while the modified lignin also undergoes its most intense thermal decomposition process at around 310-400°C, and the thermal decomposition temperature ranges of the two overlap. If magnesium hydroxide and modified lignin are present at the same time, magnesium hydroxide will generate magnesium oxide during the thermal decomposition process and adhere to the sample surface, including the surface of the modified lignin, thereby reducing the probability of contact between the modified lignin and oxygen, changing the combustion process of the modified lignin, and then promoting the carbonization and dehydration process of the modified lignin, thereby accelerating the formation of a carbonized layer on the sample surface of the modified lignin, exerting a flame retardant effect, and achieving synergistic flame retardancy with magnesium hydroxide. If only modified lignin is present, the modified lignin must burn for a period of time according to the conventional oxidation process before a carbonized layer can be formed on the sample surface, thereby exerting a flame retardant effect. Therefore, when modified lignin is used alone as a flame retardant, its flame retardant effect is not as good as the synergistic flame retardant effect of magnesium hydroxide and modified lignin.

[0119] In order to further demonstrate the improvement of the flame retardant effect and light stability of modified lignin, Example 2 is compared with Comparative Example 1. It can be seen that in the absence of modified lignin, the flame retardant performance and light stability of Comparative Example 1 are weaker than those of Example 2. This is mainly because the presence of modified lignin can produce the following effects: (1) The modified lignin itself is a hard and strong filler with multiple benzene ring structures, which can effectively reduce the mobility of the molecular chain and improve thermal stability. At the same time, it becomes a "carbon source" during the combustion process, synergistically acting with magnesium hydroxide to accelerate the formation of a carbonized layer on the sample surface and achieve better flame retardant effect. (2) The modified lignin itself is also a substance with a "hindered phenol" structure, which can effectively capture free radicals generated by sample combustion or light aging, thereby effectively reducing the degree of thermal aging and light aging of the sample.

[0120] To further demonstrate the effect of the compatibilizer, by comparing Example 2 with Examples 6 and 7, it can be seen that the effect of using PP-g-GMA as a compatibilizer is indeed better. This is mainly because the TPO material itself is a propylene-based thermoplastic polyolefin elastomer, and therefore, the effect of using a polyethylene-based compatibilizer is relatively weak. Compared with PP-g-MAH, the GMA segment in PP-g-GMA is relatively long. On the one hand, it can effectively improve the dispersibility of magnesium hydroxide in the matrix. On the other hand, it can also be closer to the modified lignin, a substance with large steric hindrance, and combine with it through hydrogen bonds and other types of electrostatic forces, thereby further improving the dispersibility of the modified lignin in the matrix to a certain extent.

[0121] Comparing Example 2 with Comparative Examples 2-5, it can be seen that the dispersibility of the lignin that has not been ground is greatly affected, which easily leads to a decrease in elongation. The dispersibility of the lignin that has been mechanically ground is improved, and the modification effect is also improved. However, since no surface modification is performed, agglomeration occurs, and the particle size is slightly larger than that of the lignin surface-modified by the solution method and the sol-gel method.

[0122] In terms of magnesium hydroxide particle size, the magnesium hydroxide used in Example 2 has a smaller particle size, while the magnesium hydroxide used in Example 8 has a larger particle size. Therefore, when the sample burns, the magnesium hydroxide in Example 2 can decompose more quickly into magnesium oxide and water, forming a magnesium oxide protective layer on the sample surface, accelerating the formation of a carbonized layer. At the same time, the generated water vapor lowers the temperature, thereby achieving a better and faster flame retardant effect. In addition, as an inorganic filler, due to its smaller particle size, Example 2 has a better mechanical property modification effect.

[0123] The above description is only a specific embodiment of the present application. Those skilled in the art will clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the scope of protection of the present application.

Claims

1. A light-resistant and flame-retardant thermoplastic polyolefin waterproof membrane, characterized in that: In parts by weight, it comprises: 60-80 parts of thermoplastic polyolefin elastomer; 5-20 parts of plastomer; 10-40 parts of flame retardant; 2 to 10 parts of light stabilizer; 1 to 5 parts of compatibilizer; 1 to 5 parts of additives; Wherein, the flame retardant and the light stabilizer both comprise modified lignin, a titanate coupling agent is grafted onto the surface of the modified lignin, and the D50 of the modified lignin is 5.0 to 8.0 nm; The flame retardant comprises magnesium hydroxide and the modified lignin, wherein the weight ratio of the magnesium hydroxide to the modified lignin is 2:1 to 5:1; The preparation method of the modified lignin comprises ball milling a material containing lignin and a titanate coupling agent to obtain the modified lignin.

2. The thermoplastic polyolefin waterproof membrane according to claim 1, characterized in that: The light stabilizer comprises the modified lignin and titanium dioxide, wherein the weight ratio of the modified lignin to the titanium dioxide is 3:1 to 10:

1.

3. The thermoplastic polyolefin waterproof membrane according to claim 1, characterized in that: The plastomer includes at least one of high-density polyethylene, homopolypropylene, block polypropylene and linear low-density polyethylene.

4. The thermoplastic polyolefin waterproof membrane according to claim 1, characterized in that: The compatibilizer includes at least one of PP-g-MAH, PP-g-GMA and PE-g-MAH.

5. The thermoplastic polyolefin waterproof membrane according to claim 1, characterized in that: The additives include an antioxidant and a masterbatch, wherein the weight portion of the antioxidant is 0.1 to 1 part, and the weight portion of the masterbatch is 1 to 4 parts.

6. The thermoplastic polyolefin waterproof membrane according to claim 1, characterized in that: The titanate coupling agent includes at least one of triisostearate isopropyl titanate, di(triethylamine) diisopropyl titanate and tetraisopropyl di(dioctylphosphite) titanate.

7. The thermoplastic polyolefin waterproof membrane according to claim 1, characterized in that: The mass ratio of the lignin to the titanate coupling agent is 10:1 to 200:

1.

8. The thermoplastic polyolefin waterproof membrane according to claim 1, characterized in that: The ball milling process is performed at a rotation speed of 300 to 1000 rpm and for a time of 1 to 3 hours.

9. The method for preparing the thermoplastic polyolefin waterproof membrane according to any one of claims 1 to 8, characterized in that: include: The materials containing thermoplastic polyolefin elastomer, plastomer, flame retardant, light stabilizer, compatibilizer and additives are mixed according to a preset ratio, and then the materials are conveyed to an extruder, and subjected to extrusion molding, calendering, pulling and winding processes to obtain a plastic polyolefin waterproof membrane; Wherein, the flame retardant and the light stabilizer both include modified lignin.

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