A fiber-reinforced polyurea-asphalt composite waterproofing membrane and a preparation method thereof

Abstract

This invention discloses a fiber-reinforced polyurea-asphalt composite waterproof membrane and its preparation method, belonging to the technical field of building waterproofing materials. The membrane comprises an upper protective layer, a fiber reinforcement layer, a polyurea-asphalt composite waterproof layer, and a lower isolation layer. Its core lies in the fact that the polyurea-asphalt composite waterproof layer is made by a specific in-situ reactive blending process of SBS-modified asphalt and reactive polyurea prepolymer, forming an interpenetrating network structure. This invention, through material and process innovation, solves the problems of poor weather resistance, insufficient corrosion resistance, and poor balance of mechanical properties in traditional asphalt membranes. The resulting membrane combines the excellent weather resistance, elasticity, and corrosion resistance of polyurea materials with the good waterproofing and adhesion of asphalt materials, while also possessing ultra-high strength, high elongation, and excellent durability, making it suitable for building waterproofing projects in various harsh environments.

Description

Technical Field

[0001] This invention relates to the field of building waterproofing materials technology, specifically to a fiber-reinforced polyurea-asphalt composite waterproof membrane and its preparation method. Background Technology

[0002] Waterproofing is a crucial step in ensuring that building structures are protected from water erosion and extending the lifespan of buildings. Currently, the mainstream waterproofing materials on the market mainly include modified bitumen waterproof membranes, polymer waterproof membranes, and waterproof coatings.

[0003] Modified bitumen waterproofing membranes are among the most widely used waterproofing materials, with SBS (styrene-butadiene-styrene block copolymer) and APP (atactic polypropylene) modified bitumen membranes holding a significant market share. However, these materials have several limitations: Firstly, most SBS modified bitumen membranes on the Chinese market have very low SBS elastomer content, some even using recycled tire powder instead of SBS elastomer, resulting in very poor membrane durability. A qualified SBS polymer-modified bitumen waterproofing membrane is more than three times the price of ordinary waterproofing membranes currently on the market. Secondly, traditional modified bitumen membranes suffer from poor weather resistance, easy aging, and insufficient low-temperature flexibility during application, especially failing to effectively adapt to substrate deformation when concrete cracks, leading to waterproofing layer rupture. Experiments show that common roofing waterproofing materials such as bitumen, SBS, and APP will crack after sun aging; even if the waterproofing material itself does not crack, it will break due to the cracking of the concrete.

[0004] Polyurea waterproofing materials are a new type of waterproofing technology developed in recent years. Polyurea is a high-performance polymer material formed by the rapid polymerization of isocyanates and amine compounds. Due to its excellent physical properties and chemical stability, polyurea has been rapidly applied and developed in the field of waterproofing materials. Polyurea has high elasticity and strong adaptability, with a tensile strength up to 56 MPa and an elongation up to 1000%. Its bond strength with concrete can reach 5 MPa, which is twice the peel strength of concrete itself (approximately 2.5 MPa). Therefore, compared with traditional waterproofing materials, it has better resistance to concrete cracking. When cracks appear in the concrete substrate, only a small area of ​​concrete peeling occurs around the crack, without causing large-scale peeling of the coating. However, polyurea materials are mainly applied by spraying, which requires high-level construction equipment and skilled workers. Furthermore, two-component polyurea requires specialized mechanical spraying equipment due to its extremely fast curing reaction. This also means that the quality stability of polyurea waterproofing systems largely depends on the construction process, making it difficult to guarantee consistent project quality.

[0005] Composite waterproof membranes attempt to combine the advantages of multiple materials, but existing technologies still have shortcomings. For example, patent CN217226903U discloses a novel composite waterproof membrane, including a base layer, an asphalt waterproof layer, a tear-resistant layer, and a light-shielding and anti-aging layer. This structure improves waterproof performance through a multi-layer design, but fails to effectively address the issue of material conformity in the event of concrete cracking. Another patent, CN114836049A, introduces a composite waterproof membrane containing components such as 70# asphalt, SMA silicone rubber modified asphalt, and modified polyvinyl chloride resin. While this improves water resistance, there is still room for improvement in tensile strength and elongation at break.

[0006] The problems with waterproof membranes in practical applications are also reflected in the extremely high leakage rate in Chinese buildings. According to a 2014 national building leakage survey report released by the China Waterproofing Association, the leakage rate of roof samples reached 95.33%, and the leakage rate of underground samples reached 57.51%. In many cities, housing prices can easily reach tens of thousands of yuan per square meter, but few construction companies are willing to install waterproofing systems with a lifespan exceeding the national standard of 5 years. This contrasts sharply with waterproofing systems in European countries like Germany, which can reliably maintain a lifespan of over 50 years.

[0007] In summary, existing waterproofing materials have the following main technical problems: Modified bitumen rolls have poor weather resistance, are prone to brittle cracking at low temperatures, and have poor adaptability to base layer deformation; Polyurea waterproofing materials have complex construction processes, are difficult to control in terms of quality, and have high material costs; Existing composite waterproof membranes cannot simultaneously achieve high strength, high elongation, aging resistance, and ease of construction. Waterproofing systems generally have a short lifespan, making it difficult to meet the long-term waterproofing needs of buildings.

[0008] Therefore, developing a new type of waterproof membrane that combines excellent mechanical properties, weather resistance, ease of construction, and long service life has become an urgent technical problem to be solved in this field. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a fiber-reinforced polyurea bitumen composite waterproof membrane and its preparation method, thereby providing a novel waterproof membrane with excellent mechanical properties, weather resistance, ease of construction, and long service life.

[0010] To solve the above problems, in a first aspect, the present invention adopts the following technical solution: A fiber-reinforced polyurea-asphalt composite waterproof membrane comprises, from top to bottom, an upper surface protective layer, a fiber reinforcement layer, a polyurea-asphalt composite waterproof layer, and a lower surface isolation layer; the polyurea-asphalt composite waterproof layer is made by in-situ reaction blending of modified asphalt and reactive polyurea prepolymer, and the polyurea-asphalt composite waterproof layer comprises, by weight, the following components: 100 parts of road petroleum asphalt, 5-15 parts of styrene-butadiene-styrene block copolymer, 10-30 parts of reactive polyurea prepolymer, 3-8 parts of tackifying resin, and 20-40 parts of filler.

[0011] Preferably, the reactive polyurea prepolymer is an isocyanate-terminated polyether prepolymer with an NCO content of 8%-15%.

[0012] Preferably, the fiber reinforcement layer is a glass fiber mesh, polyester nonwoven fabric, or polyethylene-polyester composite felt, with a basis weight of 80-200 g / m².

[0013] Preferably, the upper surface protective layer is a polyethylene film, fine sand, or mineral granules.

[0014] Preferably, the lower surface isolation layer is a silicone oil isolation film or a polyethylene film.

[0015] Secondly, the present invention also provides a method for preparing fiber-reinforced polyurea-asphalt composite waterproof membrane, comprising the following steps: S1: Preparation of modified asphalt: road petroleum asphalt is heated to 160-180℃, SBS modifier is added, and sheared at a shear rate of 3000-5000rpm for 30-60 minutes to obtain SBS modified asphalt. S2: Preparation of polyurea-asphalt composite: Cool the SBS modified asphalt obtained in step S1 to 120-140℃, add tackifying resin and filler in sequence, stir evenly, add reactive polyurea prepolymer, and react at a stirring speed of 100-200 rpm for 20-40 minutes to obtain polyurea-asphalt composite. S3: Impregnation and Composite: The fiber-reinforced substrate is impregnated and coated with the polyurea-asphalt composite material prepared by S2 to form a composite of polyurea-asphalt waterproof layer and fiber-reinforced layer; S4: Lamination and Cooling: An upper protective layer is laminated onto the upper surface of the composite, and a lower isolation layer is laminated onto the lower surface. After being compacted by pressure rollers, cooled, shaped, and rolled up, the waterproof membrane is obtained.

[0016] Preferably, the addition temperature of the reactive polyurea prepolymer is strictly controlled within the range of 120-140°C.

[0017] Preferably, in step S3, the impregnation and coating process is carried out in a heat-insulating coating machine, and the material temperature is maintained at 130-150℃.

[0018] Preferably, in step S4, the compaction pressure is 0.3-0.6 MPa.

[0019] This invention introduces reactive polyurea prepolymers for in-situ compounding, abandoning physical blending and creatively employing an in-situ chemical reaction between the reactive polyurea prepolymer and SBS-modified asphalt. Under heating and stirring conditions, the reactive polyurea prepolymer (terminal -NCO) reacts with trace amounts of moisture inherent in the asphalt, as well as active groups such as -COOH and -OH generated from the ends or degradation of SBS segments. This process generates polyurea segments or microregions in situ within the continuous asphalt phase. This "in-situ reactive blending" mechanism forms a "asphalt-SBS-polyurea" ternary interpenetrating polymer network structure, with asphalt as the continuous phase and SBS and polyurea as the dispersed reinforcing phases. This structure achieves chemical bonding at the phase interface, greatly improving compatibility, avoiding phase separation, and realizing a synergistic reinforcement effect greater than the sum of its parts (1+1>2).

[0020] This invention employs precise control of reaction temperature and process, determining a specific temperature window of 120-140℃ for the addition and reaction of the polyurea prepolymer. If the temperature is too low, the prepolymer viscosity is high, resulting in uneven dispersion and insufficient reactivity; if the temperature is too high, exceeding 160℃, side reactions may occur between the -NCO groups and the asphalt components, such as reactions with polycyclic aromatic hydrocarbons in the asphalt, excessive self-crosslinking, or excessive vaporization, leading to gelation, performance degradation, and bubble defects in the system. 120-140℃ represents the optimal balance between prepolymer flowability, reaction rate, and suppression of side reactions, ensuring a stable and uniform in-situ reaction.

[0021] This invention constructs a fiber-reinforced composite structure by embedding a fiber-reinforced layer into an innovative polyurea-asphalt composite layer, forming a multi-layered composite structure. The fiber-reinforced layer, such as polyester felt, provides extremely high tensile strength and resistance to nail bar tearing. The newly developed polyurea-asphalt composite layer not only possesses excellent adhesion and mechanical properties, but its wettability and adhesion to fibers are also significantly enhanced due to the introduction of the polyurea component. The resulting "rigid-flexible" sandwich structure allows the roll material to maintain extremely high elongation at break and resistance to deformation while possessing high strength.

[0022] Compared with the prior art, the present invention has the following significant advantages: Exceptional high and low temperature resistance: The introduction of polyurea segments greatly improves the thermal stability of the polymer. The roll material can withstand temperatures exceeding 120°C and maintain its low-temperature flexibility down to -30°C without cracking, thus offering a wider applicable temperature range.

[0023] Excellent aging and weather resistance: Polyurea's excellent UV resistance and antioxidant capacity effectively slow down the aging process of asphalt and SBS, greatly extending the service life of the roll material.

[0024] Excellent chemical corrosion resistance: The dense polyurea network structure effectively blocks the erosion of media such as acids, alkalis, and salts, making it suitable for harsh waterproofing projects such as sewage treatment plants and chemical environments.

[0025] Superior mechanical properties: The in-situ formed interpenetrating network structure and fiber reinforcement work together to enable the roll material to have both high tensile strength ≥800N / 50mm and high elongation at break ≥50%, which can effectively resist the cracking and deformation of the base layer.

[0026] Excellent economic benefits: Compared with pure polyurea coating, this invention only uses a portion of polyurea prepolymer, which significantly improves performance while increasing costs only slightly, resulting in extremely high cost-effectiveness. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the fiber-reinforced polyurea-asphalt composite waterproof membrane of the present invention.

[0028] Figure 2 This is a schematic diagram of the preparation process of the fiber-reinforced polyurea-asphalt composite waterproof membrane of the present invention.

[0029] In the diagram: 1. Upper surface protective layer; 2. Fiber reinforcement layer; 3. Polyurea-asphalt composite waterproof layer; 4. Lower surface isolation layer. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Example 1, please refer to Figure 1 , Figure 2 A fiber-reinforced polyurea-asphalt composite waterproof membrane comprises, from top to bottom, an upper surface protective layer, a fiber reinforcement layer, a polyurea-asphalt composite waterproof layer, and a lower surface isolation layer; the polyurea-asphalt composite waterproof layer is made by in-situ blending of modified asphalt and reactive polyurea prepolymer, and the polyurea-asphalt composite waterproof layer comprises, by weight, the following components: 100 parts of road petroleum asphalt, 10 parts of SBS, 20 parts of reactive polyurea prepolymer (NCO%=12%), 5 parts of tackifying resin (C5 petroleum resin), and 30 parts of talc.

[0032] Reinforcing layer: 120g / m² polyester felt.

[0033] Protective / isolation layer: The upper surface is a polyethylene film, and the lower surface is a silicone oil isolation film.

[0034] Its preparation method: Asphalt was heated to 170°C, SBS was added, and the mixture was sheared at 4000 rpm for 45 minutes to obtain SBS modified asphalt.

[0035] Cool to 130℃, add thickening resin and filler, and stir at low speed for 20 minutes.

[0036] Under continuous stirring, reactive polyurea prepolymer is slowly added, and the temperature is controlled at 130±5℃. The reaction is carried out for 30 minutes to obtain a uniform and glossy polyurea-asphalt composite material.

[0037] The polyester felt is impregnated and coated on both sides with the above-mentioned composite material using an insulation coating machine.

[0038] A PE film is laminated on the upper surface and a release film is laminated on the lower surface. The film is then compacted by a 0.4MPa pressure roller, cooled by water, and wound up to obtain roll sample A.

[0039] Example 2 is basically the same as Example 1, except that the amount of reactive polyurea prepolymer is adjusted to 15 parts, and the rest is the same as Example 1.

[0040] The preparation method is the same as in Example 1, and roll material sample B is obtained.

[0041] In Example 3, the amount of reactive polyurea prepolymer was adjusted to 25 parts, and the rest was the same as in Example 1.

[0042] The preparation method is the same as in Example 1, and roll material sample C is obtained.

[0043] For comparison, a commercially available mainstream Type II SBS modified bitumen waterproof membrane with polyester reinforcing layer (PY II) was prepared as Comparative Example D. Its bitumen layer was conventional SBS modified bitumen, without polyurea components.

[0044] Samples A, B, and C prepared according to this invention, along with comparative example D, were subjected to performance tests according to the national standard GB 18242-2008 "Elastomer-Modified Bitumen Waterproofing Membranes," with an additional chemical corrosion resistance test. The results are shown in the table below: Analysis of verification results: High and low temperature resistance: The heat resistance and low temperature flexibility of all examples (A, B, C) were significantly better than those of Comparative Example D and the national standard. Furthermore, the performance improvement became more pronounced with increasing polyurea prepolymer content (from B to C), demonstrating the direct contribution of the polyurea component to widening the operating temperature range.

[0045] Mechanical properties: The tensile strength and elongation of the embodiment are both higher than those of the comparative example, achieving an ideal combination of "high strength and high elongation". This indicates that the polyurea-asphalt interpenetrating network and the fiber reinforcement layer work synergistically to effectively improve the material's load-bearing and deformation capabilities.

[0046] Aging resistance: After thermal aging, the tensile strength retention and low-temperature performance degradation of the embodiment were much smaller than those of the comparative example, proving that the roll material of the present invention has superior long-term durability. This is due to the effective inhibition of thermo-oxidative aging by the polyurea network.

[0047] Chemical resistance: Qualitative tests showed that the surface of the roll material in the example remained unchanged after being soaked in saturated lime water for 28 days, while the surface of the comparative example showed slight softening. This verifies the beneficial effect of the corrosion resistance described in this invention.

[0048] In summary, the roll material in this embodiment outperforms traditional SBS modified bitumen rolls in all key performance indicators, especially in terms of high and low temperature resistance, mechanical properties, and durability, which verifies the advanced nature and effectiveness of the "in-situ reaction blending" technology.

[0049] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A fiber-reinforced polyurea-bitumen composite waterproof membrane, characterized in that, It includes an upper surface protective layer (1), a fiber reinforcement layer (2), a polyurea-asphalt composite waterproof layer (3), and a lower surface isolation layer (4) stacked sequentially from top to bottom; the polyurea-asphalt composite waterproof layer (3) is made by in-situ reaction blending of modified asphalt and reactive polyurea prepolymer.

2. The fiber-reinforced polyurea-bitumen composite waterproof membrane according to claim 1, characterized in that, The polyurea-asphalt composite waterproof layer (3) comprises the following components by weight: 100 parts of road petroleum asphalt, 5-15 parts of styrene-butadiene-styrene block copolymer, 10-30 parts of reactive polyurea prepolymer, 3-8 parts of tackifying resin, and 20-40 parts of filler.

3. The fiber-reinforced polyurea-bitumen composite waterproof membrane according to claim 2, characterized in that, The reactive polyurea prepolymer is an isocyanate-terminated polyether prepolymer with an NCO content of 8%-15%.

4. The fiber-reinforced polyurea-bitumen composite waterproof membrane according to claim 1, characterized in that, The fiber reinforcement layer (2) is a glass fiber mesh, polyester nonwoven fabric or polyethylene polyester composite felt, with a basis weight of 80-200g / m².

5. The fiber-reinforced polyurea-bitumen composite waterproof membrane according to claim 1, characterized in that, The upper surface protective layer (1) is a polyethylene film, fine sand or mineral granules.

6. The fiber-reinforced polyurea-bitumen composite waterproof membrane according to claim 1, characterized in that, The lower surface isolation layer (4) is a silicone oil isolation film or a polyethylene film.

7. A method for preparing the fiber-reinforced polyurea-bitumen composite waterproof membrane as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Preparation of modified asphalt: road petroleum asphalt is heated to 160-180℃, SBS modifier is added, and sheared at a shear rate of 3000-5000rpm for 30-60 minutes to obtain SBS modified asphalt. S2: Preparation of polyurea-asphalt composite: Cool the SBS modified asphalt obtained in step S1 to 120-140℃, add tackifying resin and filler in sequence, stir evenly, add reactive polyurea prepolymer, and react at a stirring speed of 100-200 rpm for 20-40 minutes to obtain polyurea-asphalt composite. S3: Impregnation and Composite: The fiber-reinforced substrate is impregnated and coated with the polyurea-asphalt composite material prepared by S2 to form a composite of polyurea-asphalt composite waterproof layer (3) and fiber-reinforced layer (2); S4: Lamination and cooling: The upper surface protective layer (1) is laminated on the upper surface of the composite, and the lower surface isolation layer (4) is laminated on the lower surface. After being compacted by pressure rollers, cooled, shaped and rolled up, the waterproof membrane is obtained.

8. The method according to claim 7, characterized in that, In step S2, the addition temperature of the reactive polyurea prepolymer is strictly controlled within the range of 120-140℃.

9. The method according to claim 7, characterized in that, In step S3, the impregnation and coating process is carried out in a heat-insulating coating machine, and the material temperature is maintained at 130-150℃.

10. The method according to claim 7, characterized in that, In step S4, the compaction pressure is 0.3-0.6 MPa.

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