A thermoplastic polyolefin waterproofing membrane and a method of making the same

Abstract

The application discloses a thermoplastic polyolefin waterproofing membrane, which mainly comprises the following components in parts by weight: 100 parts of thermoplastic polyolefin resin; 5-20 parts of porcelain-forming filler; 10-30 parts of modified reinforcing fiber; 10-50 parts of inorganic flame retardant; 0-1 part of antioxidant; 0-2 parts of light stabilizer; and 0-10 parts of pigment. The thermoplastic polyolefin waterproofing membrane has the effects of wind load washing resistance and flame retardation, and can form a dense ceramic layer in the case of fire, thereby achieving excellent flame retardation effect. Meanwhile, the thermoplastic polyolefin waterproofing membrane is firmly attached to a TPO base through self-supporting and the support of the fiber'skeleton', and is not easy to be blown away by wind load, thereby achieving good fireproof effect.

Description

Technical Field

[0001] This invention relates to the field of waterproof membranes, specifically to a thermoplastic polyolefin waterproof membrane and its preparation method. Background Technology

[0002] With the advancement of technology, modern waterproofing materials have developed rapidly. By the 1970s, various polymer waterproofing materials had emerged. my country's waterproofing materials have gradually formed three major series: waterproof membranes, waterproof coatings, and sealing materials. Among them, waterproof membranes are mainly used in building walls, roofs, tunnels, highways, landfills, etc., serving as a flexible building material that can be rolled up to resist external rainwater and groundwater seepage. As a leak-proof connection between the engineering foundation and the building structure, the waterproof membrane is the first line of defense for waterproofing the entire project, playing a crucial role. In existing technologies, based on their main waterproofing components, they can be divided into three main categories: asphalt waterproofing materials, polymer-modified waterproof membranes, and synthetic polymer waterproof membranes (such as SBC 120 polyethylene-polypropylene composite membranes). Based on the type of substrate, they are further divided into non-substrate membranes, paper-substrate membranes, fiberglass-substrate membranes, glass cloth-substrate membranes, and polyethylene-substrate membranes.

[0003] Thermoplastic polyolefin (TPO) waterproof membrane is a new type of polymer waterproof material, mainly composed of polyolefins without double bonds in the main chain, supplemented with various additives. Compared with traditional asphalt waterproof membranes, TPO waterproof membranes have many advantages such as being pollution-free, having a long service life, being weldable, recyclable, and energy-saving due to their reflective properties. It also combines the excellent weather resistance and low-temperature performance of EPDM waterproof membranes with the excellent weldability of PVC waterproof membranes. In recent years, the demand for TPO waterproof membranes has been increasing year by year. Thermoplastic polyolefin waterproof membranes have become one of the fastest-growing products in this industry.

[0004] However, thermoplastic polyolefin (TPO) waterproof membranes contain only carbon and hydrogen, have a low ignition temperature, and an oxygen index of only about 18%, making them highly flammable. During combustion, they produce flaming molten droplets, which, combined with wind loads on the roof, accelerate the spread of fire, causing it to spread rapidly and posing a significant safety hazard to people and property. Therefore, improving the flame-retardant properties of TPO waterproof membranes has become one of the urgent problems to be solved in this field.

[0005] To address the aforementioned technical issues, the main flame-retardant method for thermoplastic polyolefin (TPO) waterproof membranes currently involves directly or in combination with organic halogen-based flame retardants, organic phosphorus-based flame retardants, nitrogen-phosphorus flame retardants, and inorganic flame retardants. For example, Chinese invention patents CN107501741 A and CN104441887A disclose flame-retardant TPO waterproof membranes, both of which utilize halogen-containing compound flame retardants to improve the flame-retardant performance of the TPO waterproof membrane. However, in this flame-retardant system, the halogen-containing flame retardants release toxic hydrogen halide and dioxin gases during combustion. This is no longer a commonly used flame-retardant system. Furthermore, research has found that these flame retardants react with weather-resistant additives, causing some waterproofing projects to fail due to premature aging of the TPO waterproof membrane. In addition, Chinese invention patent CN104774357A discloses a halogen-free phosphorus-nitrogen composite flame-retardant TPO waterproof membrane and its preparation method. It uses phosphorus-nitrogen flame retardants to solve the flame retardant performance of TPO waterproof membrane. Although its flame retardant effect meets expectations, the water absorption rate in the actual process does not meet the requirements of GB 27789-2011 "Thermoplastic Polyolefin (TPO) Waterproof Membrane".

[0006] Therefore, developing a flame-retardant thermoplastic polyolefin waterproof membrane with simple processing and excellent comprehensive performance is obviously of positive practical significance. Summary of the Invention

[0007] The purpose of this invention is to provide a thermoplastic polyolefin waterproof membrane and its preparation method, so as to obtain a thermoplastic polyolefin waterproof membrane with excellent flame retardant properties and excellent overall performance.

[0008] To achieve the above-mentioned objectives, the technical solution adopted is: a thermoplastic polyolefin waterproof membrane, which, by weight, mainly comprises the following components:

[0009] 100 parts of thermoplastic polyolefin resin;

[0010] 5-20 parts of ceramic filler;

[0011] 10-30 parts of modified reinforcing fiber;

[0012] 10-50 parts of inorganic flame retardant;

[0013] Antioxidant 0-1 part;

[0014] Light stabilizer 0-2 parts;

[0015] 0-10 parts of pigment;

[0016] The ceramic filler mainly includes low melting point glass powder and at least one silicate mineral filler, wherein, by weight, the low melting point glass powder accounts for more than or equal to 50% of the ceramic filler;

[0017] The modified reinforcing fiber is an organic fiber and / or an inorganic fiber modified with a phosphate ester coupling agent, and its fiber length is 1 to 3 mm.

[0018] The surface of the fiber modified by the phosphate coupling agent is uneven, which increases its roughness. One end of the phosphate coupling agent undergoes a grafting reaction with the fiber surface to form a strong chemical bond, while the long alkane chain at the other end has a good physical entanglement with the polyolefin molecules, thereby improving the interfacial adhesion between the modified reinforced fiber and the TPO matrix.

[0019] The low-melting-point glass powder mentioned above refers to existing technology, namely low-temperature melting glass powder. It differs from regular glass powder in that its production formula and raw materials are different, and its functions are superior to those of glass powder. Low-melting-point glass powder is developed based on the thermal phase change characteristics of special glass materials and combined with the thermodynamic modification requirements of polymers. It uses high-purity, environmentally friendly inorganic non-metallic raw materials containing SiO2, P2O5, B2O3, Li2O, ZnO, BaO, K2O, Na2O, etc., which are melted and synthesized into a glass body through advanced processes, and then refined through processes such as washing, drying, coarse grinding, purity-preserving fine grinding, and precision grading.

[0020] The antioxidant mentioned is also existing technology; for example, one or more of BASF's Irganox B225, 1010, and 168 can be selected.

[0021] Preferably, the organic fiber is selected from one or more of aramid fiber, spun sulfone fiber, PBO fiber, PI fiber, and PAN fiber; the inorganic fiber is selected from one or more of carbon fiber, aluminum silicate fiber, and boron fiber.

[0022] Preferably, the inorganic flame retardant is selected from one or more of aluminum hydroxide, magnesium hydroxide, and zinc borate; the weight ratio of the low melting point glass powder to the inorganic flame retardant is 1:1 to 2.5.

[0023] Experiments revealed that the weight ratio of the low-melting-point glass powder to the inorganic flame retardant plays a crucial role. When heated, the low-melting-point glass powder melts to form a liquid phase, continuously wetting and bonding with the carbon layer generated from the pyrolysis of organic polymers, silicate minerals, and metal oxides decomposed from the inorganic flame retardant to form a eutectic mixture. This eutectic reaction results in a dense, porcelain-like structure. If the proportion of glass powder is too low, the molten liquid cannot fill the dispersed phases, resulting in a small eutectic mixture insufficient to form a dense porcelain-like structure. This leads to a loose surface carbon layer that is easily blown away by the wind. Conversely, if the proportion of glass powder is too high and the proportion of flame retardant is relatively low, it accelerates the thermal decomposition and combustion of the material, reducing the amount of porcelain-like structure formed by the eutectic reaction and affecting the flame-retardant effect.

[0024] Preferably, the melting point of the low-melting-point glass powder is 300℃~500℃.

[0025] Preferably, the thermoplastic polyolefin resin is a reactor-polymerized thermoplastic polyolefin and / or a blended thermoplastic polyolefin.

[0026] Preferably, the silicate mineral filler is selected from one or more of kaolin, mica, talc, and brucite.

[0027] Preferably, the light stabilizer is a hindered amine light stabilizer. For example, BASF's Chimasorb 2020 can be used.

[0028] Preferably, the pigment is selected from one or more of titanium dioxide, carbon black, and iron oxide.

[0029] This invention also claims protection for a method for preparing a thermoplastic polyolefin waterproof membrane, comprising the following steps:

[0030] (1) The raw material components are fed into a high-speed mixer using the above formula and stirred to obtain a uniformly stirred mixture;

[0031] (2) The mixture is fed into a co-rotating twin-screw extruder for melt extrusion;

[0032] (3) The molten material is conveyed through the die head to the three-roll calender, and then cooled, corrected, trimmed, cut, rolled up and packaged to obtain thermoplastic polyolefin waterproof membrane.

[0033] Preferably, the length-to-diameter ratio of the co-rotating twin-screw extruder is 36–48; the melt extrusion temperature of the co-rotating twin-screw extruder is 180–230°C; and the extrusion die temperature is 190–220°C. The operating temperature of the three-roll calender is 50–80°C.

[0034] The working mechanism of this invention is as follows: Low-melting-point glass powder and silicate mineral fillers are used as ceramic fillers in waterproof membranes. When a fire occurs, these fillers melt to form a liquid phase, which continuously wets and bonds with the carbon layer generated by the pyrolysis of organic polymers, silicate mineral materials, and metal oxides decomposed from inorganic flame retardants to form a eutectic mixture. Through the eutectic reaction, a hard and dense ceramic structure is further formed. At the same time, due to the addition of modified reinforcing fibers, the dense ceramic structure is also bonded to the fibers embedded in the matrix through the molten liquid phase, firmly adhering to the TPO resin layer. This not only effectively blocks the transfer and exchange of heat and combustible substances, resulting in excellent flame retardant effect, but also resists the erosion of wind loads, resulting in good fireproof effect.

[0035] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0036] 1. This invention develops a novel thermoplastic polyolefin waterproof membrane. Through the synergistic effect of ceramic filler, inorganic flame retardant, and modified reinforcing fiber, a flame-retardant thermoplastic polyolefin waterproof membrane resistant to wind load erosion is obtained. This thermoplastic polyolefin waterproof membrane can form a dense ceramic layer in the event of a fire, achieving excellent flame retardant effect. At the same time, through self-support and the "skeleton" support of the fiber, it is firmly attached to the TPO matrix and is not easily blown away by wind load, thus achieving good fire protection effect and is suitable for widespread use.

[0037] 2. The preparation method of the present invention is simple and easy to implement, has low cost, and has good commercial significance, making it suitable for widespread application. Attached Figure Description

[0038] Figure 1 This is a scanning electron microscope image of the surface of the thermoplastic polyolefin waterproof membrane after a flammability test in Embodiment 1 of the present invention. Detailed Implementation

[0039] The present invention will be further described in conjunction with the embodiments:

[0040] Example 1

[0041] See Figure 1 As shown, a thermoplastic polyolefin waterproof membrane, by weight, mainly comprises the following components:

[0042] 100 parts of thermoplastic polyolefin resin;

[0043] 10 parts of ceramic filler;

[0044] 10 parts of modified reinforcing fiber;

[0045] 20 parts of inorganic flame retardant;

[0046] 0.1 parts antioxidant;

[0047] 0.2 parts light stabilizer;

[0048] 1 part pigment;

[0049] The ceramic filler mainly includes low-melting-point glass powder and kaolin, wherein, by weight, the low-melting-point glass powder accounts for 80% of the ceramic filler; preferably, the melting point of the low-melting-point glass powder is 300℃~500℃.

[0050] The modified reinforcing fiber is an organic fiber modified with a phosphate ester coupling agent, and its fiber length is 1-3 mm. The organic fiber is selected from aramid fiber.

[0051] The antioxidant used is BASF's Irganox B225.

[0052] The inorganic flame retardant is selected from magnesium hydroxide; the weight ratio of the low melting point glass powder to the inorganic flame retardant is 1:1.5.

[0053] The thermoplastic polyolefin resin is a blended thermoplastic polyolefin. The light stabilizer is BASF's Chimasorb 2020. The pigment is selected from titanium dioxide.

[0054] The preparation method of the above-mentioned waterproof membrane includes the following steps:

[0055] (1) The above formula is accurately conveyed to the high-speed mixer for mixing by an automatic weighing device;

[0056] (2) After being mixed evenly, the mixture is conveyed to a co-rotating twin-screw extruder for melt plasticization and extrusion;

[0057] (3) The molten material is conveyed through the die head to the three-roll calender, and then cooled, corrected, trimmed, cut, rolled up and packaged to prepare TPO waterproof membrane.

[0058] The co-rotating twin-screw extruder has a length-to-diameter ratio of 38; its melt extrusion temperature is 220°C; and its die temperature is 200°C. The three-roll calender operates at a temperature of 50–80°C.

[0059] Figure 1 This is a scanning electron microscope (SEM) image of the surface of the thermoplastic polyolefin waterproof membrane after a flammability test in this embodiment. As can be seen from the image, after ignition, the waterproof membrane of this invention forms a dense, porcelain-like structure. This porcelain-like structure adheres firmly to the TPO resin layer, bonded together with the fibers embedded in the resin matrix. This not only blocks the transfer and exchange of heat and flammable substances, thus providing a flame-retardant effect, but also resists wind loads, resulting in excellent fire protection.

[0060] Example 2

[0061] A thermoplastic polyolefin waterproof membrane, the formulation and preparation method of which are the same as those in Example 1, the only difference being that the weight ratio of the low melting point glass powder and the inorganic flame retardant is 1:2.5.

[0062] Comparative Example 1

[0063] A thermoplastic polyolefin waterproof membrane, the formulation and preparation method of which are the same as those in Example 1, the only difference being that the weight ratio of the low melting point glass powder and the inorganic flame retardant is 1:0.5.

[0064] Comparative Example 2

[0065] A thermoplastic polyolefin waterproof membrane, the formulation and preparation method of which are the same as those in Example 1, the only difference being that the weight ratio of the low melting point glass powder and the inorganic flame retardant is 1:3.5.

[0066] The above embodiments and comparative examples were tested, and the results are as follows:

[0067]

[0068] The above testing methods are based on the national standard GB / T 8626-2007. Note: The carbon layer condition is determined visually.

[0069] As can be seen from the table above, the waterproof membrane of the present invention has excellent flame retardant effect. In the event of a fire, it forms a dense ceramic layer, which is firmly attached to the TPO matrix through self-support and the "skeleton" support of the fibers. It is not easily blown away by wind load, thus achieving a good fireproof effect.

[0070] Compared to Comparative Examples 1 and 2, when the weight ratio of low-melting-point glass powder to inorganic flame retardant is less than 1:1, the flame tip height increases significantly within 20 seconds, and the carbon layer delaminates, resulting in burning droplets igniting the filter paper within 20 seconds. In Comparative Example 2, when the weight ratio of low-melting-point glass powder to inorganic flame retardant is greater than 1:3, only a loose carbon layer with many pores can be formed, and a dense ceramic layer cannot be formed.

[0071] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermoplastic polyolefin waterproofing membrane characterized in that, by weight, the following components: 100 parts by weight of a thermoplastic polyolefin resin; 5-20 parts by weight of a porcelain-forming filler; 10-30 parts by weight of a modified reinforcing fiber; 10-50 parts by weight of an inorganic flame retardant; 0-1 part by weight of an antioxidant; 0-2 parts by weight of a light stabilizer; 0-10 parts by weight of a pigment; The porcelain-forming filler mainly includes a low-melting point glass powder and at least one silicate mineral filler, wherein the proportion of the low-melting point glass powder in the porcelain-forming filler is greater than or equal to 50% by weight; The modified reinforcing fiber is an organic fiber and / or an inorganic fiber modified by a phosphate coupling agent, and the fiber length is 1-3 mm; The organic fiber is selected from one or more of aramid fiber, polysulfone fiber, PBO fiber, PI fiber, and PAN fiber; and the inorganic fiber is selected from one or more of carbon fiber, aluminum silicate fiber, and boron fiber; The inorganic flame retardant is selected from one or more of aluminum hydroxide, magnesium hydroxide, and zinc borate; and the weight ratio of the low-melting point glass powder to the inorganic flame retardant is 1:1-2.5; The melting point of the low-melting point glass powder is 300-500°C; The silicate mineral filler is selected from one or more of kaolin, mica, talc, and brucite.

2. The thermoplastic polyolefin waterproofing membrane of claim 1, wherein: The thermoplastic polyolefin resin is a reaction kettle polymerization type thermoplastic polyolefin and / or a blending type thermoplastic polyolefin.

3. The thermoplastic polyolefin waterproofing membrane of claim 1, wherein: The light stabilizer is a hindered amine light stabilizer.

4. The thermoplastic polyolefin waterproofing membrane of claim 1, wherein: The pigment is selected from one or more of titanium dioxide, carbon black, and iron oxide.

5. A method of preparing a thermoplastic polyolefin waterproofing membrane, characterized by, The method comprises the following steps: (1) feeding the raw material components into a high-speed mixer according to the formula of the thermoplastic polyolefin waterproofing membrane to obtain a uniformly mixed material; (2) feeding the mixed material into a co-rotating twin-screw extruder for melt extrusion; (3) feeding the melted material through a die head into a three-roll calender, and then cooling, correcting deviation, trimming, cutting, winding, and packaging to obtain the thermoplastic polyolefin waterproofing membrane.

6. The production method according to claim 5, characterized by: The melt extrusion temperature of the co-rotating twin-screw extruder is 180-230°C, and the extrusion die head temperature is 190-220°C.

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