A protective film for waterproof membrane, its preparation method and application

Abstract

This invention relates to a protective film for waterproof membranes, its preparation method, and its application. Addressing the problem that existing waterproof membranes require film removal before installation, which is labor-intensive, this invention provides a protective film suitable for flame-resistant waterproof membranes. The raw materials for preparation include a matrix composite, polyurethane, adhesive resin, plasticizer, surface modifier, and functional additives. This protective film exhibits good barrier properties at room temperature, effectively improving the durability of the waterproof membrane. After heating, it can be used as an adhesive for waterproof membranes. As a protective film for flame-resistant waterproof membranes, it eliminates the need for film removal; the membrane can be directly heated together with the waterproof membrane before installation, effectively saving manpower and resources.

Description

Technical Field

[0001] This invention relates to the field of polymer membrane materials technology, and in particular to a protective film for waterproof membranes, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Waterproofing is a crucial aspect of road construction, directly impacting its waterproofing performance and lifespan. Commonly used waterproof membranes include SBS modified bitumen waterproof membranes and self-adhesive waterproof membranes. SBS modified bitumen waterproof membranes are made with SBS rubber-modified petroleum bitumen as the impregnation layer and polyester fiber non-woven fabric, jute cloth, or fiberglass felt as the base material, processed through multiple steps. They possess excellent weather resistance, high elasticity, fatigue resistance, and strong puncture and tear resistance, making them particularly suitable for waterproofing projects in cold regions and industrial and civil buildings subject to significant deformation and vibration. When laying this type of waterproof membrane, a blowtorch is used to heat the waterproof layer, causing the bitumen to slightly dissolve and bond to the concrete substrate. After laying, the overlaps are then bonded.

[0004] Commercially available SBS modified bitumen waterproof membranes typically have a protective film covering the surface, usually made of PP film, PE film, release paper, or silicone paper. This film primarily protects the waterproof layer during transportation and storage, preventing dust adhesion, sun protection, oxidation resistance, and waterproofing, effectively improving the membrane's durability. The protective film is removed during installation to expose the waterproof layer. However, the inventors argue that road construction often requires large quantities of waterproof membrane. Removing all protective films before installation requires significant manpower, and the removed film also needs to be removed, resulting in waste. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a protective film suitable for fire-resistant waterproof membranes. This protective film should possess good waterproof and sun-resistant properties, effectively protecting the waterproof layer of the membrane. Furthermore, the protective film can transform into a hot-melt adhesive upon heating, assisting in the bonding of the waterproof membrane. This protective film does not need to be removed before use; it can be directly applied along with the waterproof membrane after being fire-treated.

[0006] To achieve the above-mentioned technical objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a protective film for waterproof membranes, wherein the raw materials for preparing the protective film are as follows:

[0008] The matrix composite comprises 130-160 parts, including polyethylene and polyvinyl alcohol in a weight ratio of 1:0.5-0.8, 80-100 parts of polyurethane, 60-90 parts of viscous resin, 30-50 parts of plasticizer, 1-6 parts of surface modifier, and 5-20 parts of functional additives.

[0009] Currently, hot melt adhesive films used in industry typically use polyester and epoxy resin as the matrix. These components have good adhesive properties but poor film-forming properties. To improve the film-forming properties and waterproof performance of this protective film, this invention uses polyethylene glycol and polyvinyl alcohol as the composite matrix, taking into account both waterproof performance and barrier properties.

[0010] Furthermore, the polyethylene is preferably high-density polyethylene (HDPE); the polyvinyl alcohol is preferably of medium degree of polymerization, with a molecular weight of 120,000 to 150,000, and the degree of partial alcoholysis is usually 87% to 89%.

[0011] The polyurethane mentioned above is preferably a polyether-type polyurethane.

[0012] The above-mentioned viscous resin is a thermoplastic resin, preferably a natural resin and its derivatives, such as: rosin (grease rosin, tall oil rosin, wood rosin), rosin derivatives (hydrogenated rosin, disproportionated rosin, polymerized rosin, esterified rosin, maleic acid rosin) and terpene resins (α-terpene resin, β-terpene resin, terpene phenolic resin).

[0013] The plasticizer is paraffin oil or silicone oil.

[0014] The surface modifier is preferably a silane, and the selectable models are KH550, KH560, KH570, KH792, DL602 or DL171.

[0015] The functional additive is selected from one or a combination of ultraviolet absorbers, antioxidants, and light stabilizers. In a feasible embodiment verified by the present invention, the ultraviolet absorber is selected from 2-hydroxy-4-n-octyloxybenzophenone (UV-531), 2-hydroxy-4-dodecyloxybenzophenone (UV-538), and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (UV-571). The light stabilizer is bis(2,2,6,6'-tetramethyl-4-piperidine) sebacate.

[0016] A second aspect of the present invention provides a method for preparing a protective film for waterproof membranes as described in the first aspect, comprising the following steps:

[0017] The matrix composite, polyurethane, and plasticizer in the above proportions are stirred thoroughly at 200-240°C for 60-120 minutes. Surface modifier is added, and the temperature is raised to 220-280°C while stirring continuously. After no visible raw material particles remain, viscous resin and functional additives are added, and the mixture is kept warm and stirred for another 100-200 minutes to obtain a molten material. The molten material is then transferred to a twin-screw co-extrusion casting system and extruded through a single-layer die, stretching it to the required thickness in the casting zone. The feeding temperature is not lower than 160°C, the extrusion temperature is not lower than 200°C, and the extrusion die temperature is 200°C-230°C.

[0018] Preferably, the feeding temperature is 160~180℃, the extrusion temperature is 200~240℃, and the temperature zones during the feeding to extrusion process are set as follows: 175~185℃, 195~205℃, 215~225℃, 235~245℃.

[0019] Preferably, the temperature of the casting zone is 80~90℃, the draw ratio is 20~40, and the film thickness is 30~60μm.

[0020] Thirdly, the present invention provides a waterproof membrane using the protective film described in the first aspect.

[0021] The waterproof membrane is preferably a fire-resistant waterproof membrane, and more preferably a fire-resistant SBS modified bitumen waterproof membrane.

[0022] The waterproof membrane is laminated as follows: the width of the protective film is greater than that of the waterproof membrane, and the waterproof membrane is placed between the two protective films.

[0023] Another feasible method of coating is as follows: the width of the protective film is greater than that of the waterproof membrane, the waterproof membrane is placed in the center of the protective film, and the excess part is bent inward to protect the edge of the waterproof membrane.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. This invention provides a protective film suitable for waterproof membranes. The protective film has good barrier properties at room temperature, effectively preventing water vapor from contacting the waterproof layer of the membrane, and also has certain sun protection and anti-oxidation effects, which can effectively improve the waterproof effect and durability of the waterproof membrane.

[0026] 2. The aforementioned protective film possesses certain adhesive properties after hot melting, with a melting temperature of approximately 150-170℃, close to the melting temperature of asphalt in SBS bitumen-based waterproof membranes. Therefore, this protective film is particularly suitable as a protective film for fire-resistant bitumen waterproof membranes. It not only effectively protects the waterproof layer of the membrane, but after heating, it can also be directly used as an adhesive to enhance the adhesion between the waterproof membrane and the concrete substrate. This eliminates the need for manual removal of the membrane before installation, achieving full utilization of the membrane material and reducing resource waste.

[0027] 3. Current research on hot-melt film materials is relatively lacking. Existing studies often only achieve the effect of gelation after hot melting or melting and volatilization after hot melting, making it difficult to simultaneously achieve the barrier properties and gelation properties of the film. This invention provides a high-performance protective film material by optimizing the composition and preparation process, which is of great significance for simplifying the construction steps of waterproof membranes and improving the efficiency of road paving. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 This is a schematic diagram of the waterproof membrane coating method in Example 5;

[0030] Among them, 11 and 12 are protective films, 20 is waterproof membrane, and 101 is an extension.

[0031] Figure 2 This is a schematic diagram of another waterproof membrane coating method in Example 5;

[0032] Among them, 10 is the protective film, 20 is the waterproof membrane, and 101 is the extension.

[0033] Figure 3 This is a schematic diagram of the waterproof membrane overlap structure described in Example 5;

[0034] Among them, 10 represents the waterproof membrane, and 20 represents the overlapping area. Detailed Implementation

[0035] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0038] The following examples involve the following raw material types:

[0039] Polyethylene: Item No. HHM5502LW.

[0040] Polyvinyl alcohol: Model 2488, Item No. 2021070812.

[0041] Disproportionated rosin: Model TA1201 water-white resin, Product No. AL640780423312, Grade

[0042] TA1201.

[0043] Polyether-type polyurethane: flame-retardant polyether-type TPU with a hardness of 60A.

[0044] Silane coupling agents: KH570 (CAS: 2530-85-0), KH560 (CAS: 2530-83-8).

[0045] The following are ultraviolet absorbers:

[0046] Model: UV-531, CAS: 1843-05-6, Chemical Name: 2-Hydroxy-4-n-Octyloxybenzophenone;

[0047] Model: UV-538, CAS: 2985-59-3, Chemical Name: 2-hydroxy-4-dodecyloxybenzophenone;

[0048] Model: UV-571, CAS: 125304-04-3, Chemical name: 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol.

[0049] Light stabilizer: Tinuvin 770, CAS: 52829-07-9, bis(2,2,6,6,-tetramethyl-4-piperidine) sebacate.

[0050] SBS modified bitumen waterproof membrane: Model YHLS-003, tensile strength 500, tear strength 500, thickness 3mm, compressive strength 0.2MPa.

[0051] Example 1

[0052] In this embodiment, a protective film for waterproof membrane is provided, and the raw materials for preparing the protective film are as follows:

[0053] The matrix composite consists of 150 parts (100 parts polyethylene and 50 parts polyvinyl alcohol), 90 parts polyether polyurethane, 85 parts disproportionated rosin, 40 parts paraffin oil, 4 parts KH550 silane surface modifier, and 15 parts Tinuvin 770 light stabilizer.

[0054] The preparation method of the above protective film is as follows: Preheat the reactor to 220°C, add the matrix composite, polyether polyurethane, and paraffin oil to the reactor and stir thoroughly for 60 minutes at a stirring rate of 120 r / min. Add KH570 to the reactor and raise the temperature to 260°C while continuing to stir. After all the raw materials in the reactor have melted, add disproportionated rosin and light stabilizer Tinuvin 770, and continue to maintain the temperature at 260°C for 120 minutes at a stirring rate of 80 r / min to obtain the molten material.

[0055] The molten material was transferred to a twin-screw co-extrusion casting system and extruded through a single-layer die head. The temperatures of each zone from feeding to extrusion were set to 180℃, 200℃, 220℃, and 240℃, respectively. The temperature of the single-layer extrusion die head was set to 210℃, and the screw speed was 80 r / min. The temperature of the casting zone was set to 85℃, the draw ratio was 30, and the film thickness was 50 μm.

[0056] Example 2

[0057] In this embodiment, another protective film for waterproof membranes is provided, the raw materials for which the protective film is prepared are as follows:

[0058] The matrix composite consists of 130 parts (72 parts polyethylene and 58 parts polyvinyl alcohol), 80 parts polyether polyurethane, 60 parts disproportionated rosin, 30 parts paraffin oil, 1 part KH550 silane surface modifier, and 20 parts Tinuvin770 light stabilizer.

[0059] The preparation method of the above protective film is as follows: Preheat the reactor to 200℃, add the matrix composite, polyether polyurethane, and paraffin oil to the reactor and stir thoroughly for 120 min at a stirring rate of 100 r / min. Add KH560 to the reactor and raise the temperature to 220℃ while continuing to stir. After all the raw materials in the reactor have melted, add disproportionated rosin and light stabilizer Tinuvin 770, and continue to maintain the temperature at 220℃ for 200 min at a stirring rate of 100 r / min to obtain the molten material.

[0060] The molten material was transferred to a twin-screw co-extrusion casting system and extruded through a single-layer die. The temperatures of each zone from feeding to extrusion were set to 180℃, 200℃, 220℃, and 240℃, respectively. The temperature of the single-layer extrusion die was set to 200℃, and the screw speed was 75 r / min. The temperature of the casting zone was set to 80℃, the draw ratio was 20, and the film thickness was 58 μm.

[0061] Example 3

[0062] In this embodiment, another protective film for waterproof membranes is provided, the raw materials for which the protective film is prepared are as follows:

[0063] The matrix composite consists of 160 parts (100 parts polyethylene and 60 parts polyvinyl alcohol), 100 parts polyether polyurethane, 90 parts disproportionated rosin, 50 parts paraffin oil, 6 parts KH550 silane surface modifier, and 20 parts Tinuvin770 light stabilizer.

[0064] The preparation method of the above protective film is as follows: Preheat the reactor to 240℃, add the matrix composite, polyether polyurethane, and paraffin oil to the reactor and stir thoroughly for 100 min at a stirring rate of 80 r / min. Add KH560 to the reactor and raise the temperature to 280℃ while continuing to stir. After all the raw materials in the reactor have melted, add disproportionated rosin and light stabilizer Tinuvin 770, and continue to maintain the temperature at 280℃ while stirring for 100 min at a stirring rate of 100 r / min to obtain the molten material.

[0065] The molten material was transferred to a twin-screw co-extrusion casting system and extruded through a single-layer die. The temperatures of each zone from feeding to extrusion were set to 180℃, 200℃, 220℃, and 240℃, respectively. The temperature of the single-layer extrusion die was set to 230℃, and the screw speed was 80 r / min. The temperature of the casting zone was set to 90℃, the draw ratio was 40, and the film thickness was 30 μm.

[0066] Example 4

[0067] In this embodiment, another protective film for waterproof membrane is provided. The difference from Embodiment 1 is that the functional additive is UV absorber UV-531. Replacing UV-538 and UV-571 with the same weight parts can achieve similar effects.

[0068] Example 5

[0069] This embodiment provides an SBS fire-resistant waterproof membrane and its construction method. The SBS fire-resistant waterproof membrane and the protective film from the above embodiment are coated and protected by a coating roller assembly. The coating method can be as follows: Figure 1 or Figure 2 As shown:

[0070] Figure 1 In this structure, 20 is the waterproof membrane 20, 11 and 12 are protective films, and 13 is the portion of the protective films 11 and 12 that extend beyond the waterproof membrane 20. 12 covers the lower surface of the waterproof membrane 20 to enhance the adhesion between the waterproof membrane 20 and the concrete substrate. During installation, a blowtorch is used to heat the protective film 12 and the waterproof membrane until the protective film is molten and asphalt oil slightly seeps out, at which point they are bonded together. The protective film 11 is adhered to the upper surface of the waterproof membrane 20 to enhance the adhesion between the waterproof membrane 20 and the subsequently poured concrete; it can also be removed directly as needed during construction. The extended portion 13 can be used to reinforce the overlap joints of the waterproof membrane.

[0071] Figure 2 In this structure, a protective membrane 10 covers the ground surface of the waterproof membrane 20 to enhance the adhesion strength between the waterproof membrane 20 and the concrete substrate. The portion of the protective membrane that extends beyond the waterproof membrane is called an extension 101, which bends inward to protect the edges of the waterproof membrane 20.

[0072] Figure 3 This is a schematic diagram of the overlapping and laying of waterproof membrane. In the diagram, 10 represents waterproof membrane, and 20 represents the overlapping area of ​​waterproof membrane 10, with a width of approximately 8-10cm.

[0073] The above Figure 1 , Figure 2 The extension 101 of the protective film can be used as adhesive for the overlapping area. After being heated by a blowtorch, the seam is bonded. Then, the bonded roll is sealed with a liquefied gas spray gun.

[0074] Comparative Example 1

[0075] In this embodiment, another protective film for waterproof membranes is provided, which differs from Example 1 in that the matrix composite is 150 parts of polyvinyl alcohol.

[0076] Comparative Example 2

[0077] In this embodiment, another protective film for waterproof membrane is provided, which differs from Embodiment 1 in that the polyurethane is 150 parts polyester polyurethane.

[0078] Performance testing

[0079] Water vapor transmission rate detection

[0080] The water vapor transmission rate of the membrane material was determined using the simulated wet cup method according to standard GB / T 1037-1988. The membrane materials from the above examples and comparative examples were cut to the same size and placed in a water vapor transmission rate tester. The ambient humidity was controlled at 90%, the temperature at 25℃, and the weighing interval was controlled to not exceed 15 minutes. Each group was measured in parallel five times, and the transmission rate was calculated using the following formula:

[0081] Water vapor transmission coefficient ( WVP =Δm×d / S×t×Δp

[0082] Where Δm is the mass gain of the membrane within a fixed time interval, d is the thickness of the membrane material, S is the area of ​​the membrane, t is the measurement time interval, and Δp is the water vapor pressure difference across the membrane.

[0083] The results of water vapor permeation are shown in Table 1 below:

[0084] Table 1. Water vapor permeation coefficients of membrane materials in Examples 1-4 and Comparative Examples 1-2

[0085]

[0086] Adhesion performance

[0087] The protective film from Examples 1-4 was laid on the surface of the SBS modified bitumen waterproof membrane. The membrane-coated waterproof membrane was repeatedly passed through the slit between two traction rollers and left to stand for 12 hours to allow the protective film to bond tightly with the waterproof membrane, thus obtaining the corresponding membrane-coated waterproof membrane. Performance tests were conducted according to GB / T 328-2007 "Test Methods for Waterproof Membranes in Buildings". The test results are shown in Table 2 below.

[0088] Table 2 Peel strength of coated waterproof membrane

[0089]

[0090] The protective films provided in Examples 1-4 above have good barrier properties and can effectively prevent water vapor from passing through. However, the barrier properties of Comparative Example 1, which uses a single matrix composite, show a significant decrease. In the research process of this invention, a comparative example using polyethylene as a single matrix composite was also studied, and the barrier properties also showed a downward trend.

[0091] In Comparative Example 2, this invention explored the selection of polyurethane raw materials, with polyester-type polyurethane commonly used in the preparation of adhesive materials. However, according to the measurements of this invention, polyester-type polyurethane in the above-mentioned component system is detrimental to the barrier properties of the film. Furthermore, the adhesive properties of the film after hot-melt bonding were significantly reduced after the introduction of polyester-type polyurethane.

[0092] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A protective film for waterproof membrane rolls, characterized in that, The raw materials for preparing the protective film are as follows: The matrix composite consists of 130-160 parts of polyethylene and polyvinyl alcohol in a mass fraction ratio of 1:0.5-0.8, 80-100 parts of polyurethane, 60-90 parts of adhesive resin, 30-50 parts of plasticizer, 1-6 parts of surface modifier, and 5-20 parts of functional additives. The polyethylene is high-density polyethylene; the polyvinyl alcohol is of medium degree of polymerization, with a molecular weight of 120,000 to 150,000, and is partially alcoholyzed, with a degree of alcoholysis of 87% to 89%. The polyurethane is a polyether-type polyurethane; the adhesive resin is disproportionated rosin. The plasticizer is paraffin oil.

2. The protective film for waterproof membranes as described in claim 1, characterized in that, The surface modifier is a silane, selected from KH560 or KH570; The functional additive is an ultraviolet absorber or a light stabilizer: the ultraviolet absorber is selected from 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, and the light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidine) sebacate.

3. The method for preparing the protective film for waterproof membrane according to claim 1 or 2, characterized in that, Includes the following steps: The matrix composite, polyurethane, and plasticizer are thoroughly stirred at 200-240℃ for 60-120 minutes. A surface modifier is added, and the temperature is raised to 220-280℃ while stirring continuously. After no visible raw material particles are found, viscous resin and functional additives are added, and the mixture is kept warm and stirred for another 100-200 minutes to obtain a molten material. The molten material is then transferred to a twin-screw co-extrusion casting system and extruded through a single-layer die, stretching it to the required thickness in the casting zone. The feeding temperature is not lower than 160℃, the extrusion temperature is not lower than 200℃, and the temperature of the extrusion die is 200℃-230℃.

4. The method for preparing the protective film for waterproof membrane as described in claim 3, characterized in that, The feeding temperature is 160~180℃, the extrusion temperature is 200~240℃, and the temperature zones during the feeding and extrusion process are set as follows: 175~185℃, 195~205℃, 215~225℃, 235~245℃.

5. The method for preparing the protective film for waterproof membrane as described in claim 3, characterized in that, The temperature of the casting zone is 80~90℃, the draw ratio is 20~40, and the film thickness is 30~60μm.

6. A waterproof membrane using the protective film described in claim 1 or 2.

7. The waterproof membrane as described in claim 6, characterized in that, The waterproof membrane is a fire-resistant SBS modified bitumen waterproof membrane.

8. The waterproof membrane as described in claim 6, characterized in that, The waterproof membrane is laminated as follows: the width of the protective film is greater than that of the waterproof membrane, and the waterproof membrane is placed between the two protective films; Alternatively, the protective film is wider than the waterproof membrane, and the waterproof membrane is placed in the center of the protective film, with the excess portion bent inward to protect the edges of the waterproof membrane.

Images