Polyvinyl resin composition, polyethylene film and method for producing and using the same

Abstract

This invention provides a polyethylene-based resin composition, a polyethylene film, a method for preparing the same, and their applications, belonging to the technical field of polyethylene film. The polyethylene-based resin composition comprises: 50-95 parts of polyethylene resin, 0.5-15 parts of polyethylene terephthalate-1,4-cyclohexanediol resin, and 1-30 parts of additives containing inorganic fillers, including calcium powder and carbon black. The polyethylene film made from the polyethylene-based resin composition provided by this invention exhibits excellent appearance uniformity and performance stability.

Description

Technical Field

[0001] This invention relates to the field of polyethylene film technology, and more particularly to a polyethylene-based resin composition, a polyethylene film, a method for preparing the same, and its applications. Background Technology

[0002] Polyethylene (PE), as a general-purpose thermoplastic resin, is widely used in the production of films, sheets and various pipe fittings due to its excellent chemical stability, low cost and ease of molding.

[0003] In actual industrial production, to impart specific functionalities to PE products (such as antistatic, light-shielding, and reinforcement) or reduce raw material costs, inorganic fillers such as carbon black and calcium powder are usually added to the PE matrix for modification. However, PE molecular chains are composed of nonpolar carbon-hydrogen bonds, making them typical low-polarity materials, while fillers such as carbon black or calcium powder often have strong polar groups on their surfaces. The extremely poor interfacial compatibility between the two makes it difficult for the fillers to exist stably in the PE matrix. In addition, based on the comprehensive requirements of strength, processing stability, and cost, low melt index PE is usually mainly used in PE products. However, low melt index PE has poor fluidity in the molten state. During the processing of high-filler systems, it is difficult for the fillers to be uniformly dispersed through mechanical shearing, resulting in appearance defects such as surface flow lines, uneven thickness, and color differences in processed products such as films and sheets, which seriously affect the appearance quality and physical properties of the products. Summary of the Invention

[0004] In view of this, in order to at least partially solve the aforementioned technical problems, the present invention provides a polyethylene resin composition, a polyethylene film, a method for preparing the same, and its applications.

[0005] According to one aspect of the present invention, a polyethylene-based resin composition is provided, comprising, by weight parts:

[0006] 50-95 parts polyethylene resin, 0.5-15 parts polyethylene terephthalate-1,4-cyclohexanediol ester resin, and 1-30 parts additives containing inorganic fillers, including calcium powder and carbon black.

[0007] According to another aspect of the present invention, a method for preparing a polyethylene film is provided, comprising:

[0008] The above-mentioned polyethylene resin composition is mixed at a temperature of 50°C to 70°C to obtain a mixture, wherein the mixing time is greater than 1 hour;

[0009] The mixture is processed through a film-forming process to obtain a polyethylene film, wherein the film-forming process is blown film.

[0010] According to another aspect of the present invention, a polyethylene film is provided, wherein the polyethylene film comprises a single-layer polyethylene film or a multilayer co-extruded polyethylene film.

[0011] According to another embodiment of the present invention, a composite bitumen waterproof membrane is provided, comprising the aforementioned polyethylene film.

[0012] According to the polyethylene resin composition provided in the above embodiments of the present invention, polyethylene terephthalate-1,4-cyclohexanediethanol ester (PETG) resin is introduced into the polyethylene resin (PE) system through blending. The polarity of the PE resin system is regulated by utilizing the large number of polar groups (ester groups, ether bonds, conjugated benzene rings) on the PETG molecular chain, thereby improving its compatibility with inorganic fillers and enhancing the dispersion uniformity of inorganic fillers in PE products. Under the premise of ensuring high production efficiency, the appearance uniformity and performance stability of polyethylene resin molded products are significantly improved, thereby extending their service life without increasing the amount of antioxidants added. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0014] Figure 1 A flowchart illustrating a method for preparing a polyethylene film according to an embodiment of the present invention;

[0015] Figure 2 The image shows a physical picture of the polyethylene film prepared in Comparative Example 2.

[0016] Figure 3A This is a photograph of the blown film process in Comparative Example 3.

[0017] Figure 3B This is a photograph of the polyethylene film prepared in Comparative Example 3.

[0018] Figure 4A A photograph of the polyethylene film prepared in Comparative Example 1.

[0019] Figure 4B This is a photograph of the polyethylene film prepared in Example 1.

[0020] Figures 5A-5B A photograph of the actual object showing the fluctuations during the blown film process in Comparative Example 4;

[0021] Figure 6A A photograph of the composite bituminous waterproof membrane including the polyethylene film of Example 1 in its untreated state; and

[0022] Figure 6BThis is a photograph of a composite bituminous waterproof membrane, including the polyethylene film of Example 1, after artificial weathering treatment. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. However, this invention can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the invention thorough and complete, and to fully convey the scope of the invention to those skilled in the art. In the accompanying drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated, and the same reference numerals denote the same elements throughout.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0025] In related technologies, (1) PE molded products with certain requirements for product strength, toughness and production efficiency mostly use high-density polyethylene (HDPE) with low melt index as the main raw material, because it provides high melt strength and high crystallization speed. However, its low fluidity and low polarity make it easy to have uneven dispersion when it is blended with masterbatch of inorganic fillers such as carbon black and calcium powder and melt extruded by single screw. Specifically, it manifests as uneven appearance, different filling amounts at different positions, and unstable mechanical properties, which is particularly significant in film products. Due to the poor fluidity and low polarity of the matrix, the modification of filler masterbatch by using dispersants such as paraffin and EBS has little effect. (2) The practice of using high melt index PE (low molecular weight or low density) to blend and modify low melt index PE system to improve overall fluidity will lead to a decrease in product toughness, a decrease in production rate and a decrease in heat resistance. In blown film products, it will also lead to unstable film bubbles and affect product quality. (3) Using single maleic anhydride grafted polyethylene (PE-g-MAH) to regulate the polarity of PE, the amount added is too large, the cost is high, and PE-g-MAH is mostly linear low-density polyethylene (LLDPE) or low-density polyethylene (LDPE). Excessive addition will lead to a decrease in the strength of PE products and a reduction in production efficiency.

[0026] To address the problem of poor compatibility between inorganic fillers and polyethylene (PE) matrix in related technologies, this invention provides a highly dispersed polyethylene resin composition, a polyethylene film, its preparation method, and its application. This invention can effectively solve the problem of uneven dispersion of inorganic fillers during high-speed melt extrusion production of PE matrix, improve the appearance uniformity and performance stability of PE molded products, and thus extend their service life. Furthermore, this process is simple, low-cost, and has significant industrial application value.

[0027] According to an exemplary embodiment of the present invention, the present invention provides a polyethylene resin composition comprising:

[0028] 50-95 parts polyethylene resin, 0.5-15 parts polyethylene terephthalate-1,4-cyclohexanediol ester resin (PETG), and 1-30 parts additives containing inorganic fillers, including calcium powder and carbon black.

[0029] In some embodiments, the weight parts of polyethylene resin may be, for example, 50, 60, 70, 80, 90, or 95, but are not limited to the values ​​listed; the weight parts of polyethylene terephthalate-1,4-cyclohexanediol ester resin may be, for example, 0.5, 1, 5, 10, or 15, but are not limited to the values ​​listed; and the weight parts of the additive containing inorganic fillers may be, for example, 1, 5, 10, 20, 25, or 30, but are not limited to the values ​​listed.

[0030] In some embodiments, the polyethylene resin (PE resin) includes one or more of high-density polyethylene (HDPE), medium-density polyethylene (MDPE), and linear low-density polyethylene (LLDPE); wherein, the high-density polyethylene (HDPE) with a low melt index (less than 1.0 g / 10 min) accounts for more than 50% by weight in the polyethylene resin.

[0031] In some embodiments, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), and linear low-density polyethylene (LLDPE) each independently meet the following condition: density is 0.915 g / cm³. 3 ~0.960g / cm 3 The melt index at 190°C and 2.16KG is between 0.15g / 10min and 3.0g / 10min.

[0032] In some embodiments, high-density polyethylene (HDPE) may be, for example, Sinopec's TR144.

[0033] In some embodiments, medium-density polyethylene (MDPE) may be, for example, ExxonMobil's Energizer 4009MC (Enable 4009MC).

[0034] In some embodiments, linear low-density polyethylene (LLDPE) may be, for example, 7042 from Zhenhai Refining & Chemical Co., Ltd.

[0035] In embodiments of the present invention, by controlling the weight percentage of HDPE with a melt index of less than 1.0 g / 10 min in PE resin to be greater than 50%, the strength of PE products formed from the polyethylene-based resin composition and the stability of the production process (such as the stability of blown film bubbles) can be guaranteed.

[0036] In some embodiments, the weight ratio of polyethylene resin to polyethylene terephthalate-1,4-cyclohexanediol resin (PETG) is 1:(0.005~0.25), and the weight ratio can be, for example, 1:0.005, 1:0.01, 1:0.05, 1:0.1, 1:0.25, but is not limited to these values. If the amount of PETG is too low (the weight ratio of PE to PETG is greater than 1:0.005), it will be difficult to improve the uniformity of dispersion of inorganic fillers in the PE resin matrix. If the amount of PETG is too high (the weight ratio of PE to PETG is less than 1:0.25), it is easy to cause problems such as holes in the blown film due to incompatibility between PETG and PE resin.

[0037] In some embodiments, the intrinsic viscosity (IV) of polyethylene terephthalate-1,4-cyclohexanediethanol ester resin (PETG resin) is less than 1.0 dL / g, the end carboxyl group content of PETG resin is less than or equal to 35 mol / ton, and the diethylene glycol content of PETG resin is less than or equal to 1.5%.

[0038] In embodiments of the present invention, excessively high intrinsic viscosity of PETG can affect its dispersion uniformity in the PE resin system. By controlling the intrinsic viscosity of PETG to less than 1.0 dL / g, good dispersion of PETG in the PE resin system can be achieved. Excessively high terminal carboxyl group content in PETG resin can reduce the thermal stability of PETG and introduce processing stability problems. By controlling the terminal carboxyl group content of PETG to less than or equal to 35 mol / ton, PETG can maintain better processing stability. Diethylene glycol, as an impurity in PETG, will more easily absorb water if its content is too high, introducing processing stability problems. Therefore, the diethylene glycol content is controlled within the aforementioned range.

[0039] In some embodiments, the PETG resin may be, for example, CR-5511 from China Resources Chemical.

[0040] In embodiments of the present invention, polyethylene terephthalate-1,4-cyclohexanediethanol ester (PETG) resin is introduced into the PE resin system through blending, and the weight ratio of PE resin to PETG resin is controlled within the above-mentioned range. This allows for the polarity regulation of the PE resin system by utilizing the large number of polar groups (ester groups, ether bonds, conjugated benzene rings) on the PETG molecular chain, thereby improving the compatibility between low melt index polyethylene resin and inorganic fillers. This enhances the uniformity of inorganic filler dispersion in PE products and effectively solves the problem of uneven dispersion of inorganic fillers during the high-speed production of low melt index polyethylene resin melt extrusion.

[0041] In some embodiments, the inorganic filler further includes 0.1 to 5 parts of calcium oxide.

[0042] In some implementations, the additives containing inorganic fillers include at least one of the following: polyethylene masterbatch filled with calcium powder (PE calcium masterbatch) as filler; polyethylene masterbatch filled with carbon black (PE carbon black masterbatch) as an anti-aging agent; and polyethylene masterbatch filled with calcium oxide (PE defoaming masterbatch) as a defoamer.

[0043] In some embodiments, the inorganic filler-containing additives in the polyethylene resin composition include: 0.5 to 20 parts of polyethylene masterbatch filled with calcium powder (PE calcium masterbatch), 0.5 to 10 parts of polyethylene masterbatch filled with carbon black (PE carbon black masterbatch), and 0.1 to 5 parts of polyethylene masterbatch filled with calcium oxide (PE defoaming masterbatch).

[0044] In some embodiments, the calcium powder in the calcium-filled polyethylene masterbatch (PE calcium masterbatch) has a particle size of 300-3000 mesh, and the calcium powder accounts for more than 80% of the weight (calcium powder filling concentration) of the PE calcium masterbatch.

[0045] In some embodiments, the carbon black in the carbon black-filled polyethylene masterbatch (PE carbon black masterbatch) has a particle size of 300-3000 mesh, and the carbon black accounts for more than 40% of the weight of the PE carbon black masterbatch.

[0046] In some embodiments, the calcium oxide in the calcium oxide-filled polyethylene masterbatch (PE defoaming masterbatch) has a particle size of 300-3000 mesh, and the calcium oxide accounts for more than 40% of the weight of the PE defoaming masterbatch.

[0047] In an embodiment of the present invention, PE defoaming masterbatch (calcium oxide) is used to absorb trace amounts of moisture absorbed from the environment by PETG due to its polar groups and amorphous structure, thereby improving the mixing efficiency of the composition (shortening the high-mixing drying time) and solving the appearance defects caused by water bubbles in the extrusion process.

[0048] In some embodiments, the PE calcium masterbatch preferably uses LLDPE resin as a carrier, 300-3000 mesh calcium powder as filler, with a filling concentration of more than 80%, and is modified with EBS dispersant, such as 221 from Fine Calcium Industry.

[0049] In some embodiments, the PE carbon black masterbatch preferably uses LLDPE resin as a carrier, has a filler concentration of 40% or more, and is formulated with antioxidants, such as Cabot's PE2772. Antioxidant types include, for example, BASF 168 and BASF 1010.

[0050] In some embodiments, the PE defoaming masterbatch preferably uses LLDPE resin as a carrier, fills with 300~3000 mesh calcium oxide, and has a filling concentration of more than 40%, such as DM-1118 from Luxin Environmental Protection.

[0051] In the embodiments of this invention, LLDPE resin is used as the carrier. Because LLDPE resin has good flowability, it facilitates the dispersion of the masterbatch in the PE-based resin. If the mesh size of the inorganic filler is too small (i.e., the particle size is too large), it is prone to film rupture; if the mesh size is too large (i.e., the particle size is too small), it is prone to agglomeration. Furthermore, the higher the filling concentration of the inorganic filler, the better; the less it is used, the lower the cost, but this needs to be determined based on the actual achievable addition amount of commercially available products.

[0052] In addition, the thickness of polyethylene film made from polyethylene-based resin composition is usually less than or equal to 30 μm. By controlling the size of calcium powder, carbon black, and calcium oxide within the above range, the thickness of polyethylene film can be adapted to avoid the film-forming quality of polyethylene film being deteriorated due to the excessive size of calcium powder, carbon black, and calcium oxide.

[0053] In some embodiments, the above-described polyethylene resin composition further includes 0 to 5 parts of a compatibilizer, the compatibilizer including epoxy-modified ethylene polymer resin; the epoxy-modified ethylene polymer resin includes at least one of glycidyl methacrylate-grafted polyethylene (PE-g-GMA) and glycidyl methacrylate-grafted polyolefin elastomer (PE-g-GMA).

[0054] In some embodiments, the epoxy-modified ethylene polymer resin may be, for example, Shenghao Plastics' SH030 (PE-g-GMA) or Keais' W5D (POE-g-GMA).

[0055] In embodiments of the present invention, glycidyl methacrylate (GMA)-grafted ethylene polymer is used to compatibilize the PE / PETG blend system, improving processing stability and eliminating product appearance defects caused by poor compatibility between PE and PETG. In particular, the GMA-grafted ethylene polymer can promote the compatibility between PETG and PE resin when using a large amount of PETG, thereby improving the uniformity and service life of polyethylene films made from polyvinyl resin compositions.

[0056] The highly dispersed PE composition provided by this invention has a simple process and low cost. It can improve the dispersion efficiency and dispersion uniformity of inorganic fillers in low melt index PE resin matrix. Under the premise of ensuring high production efficiency, it can significantly improve the appearance uniformity and performance stability of PE molded products, thereby extending their service life without increasing the amount of antioxidants added.

[0057] Figure 1 A flowchart illustrating a method for preparing a polyethylene film according to an embodiment of the present invention.

[0058] According to an exemplary embodiment of the present invention, the present invention provides a method for preparing a polyethylene film, see below. Figure 1 As shown, it includes: operations S1 to S2.

[0059] In operation S1, the above-mentioned polyethylene resin composition is mixed at a temperature of 50°C to 70°C to obtain a mixture, wherein the mixing time is greater than 1 hour.

[0060] In some embodiments, the mixing temperature may be, for example, 50°C, 60°C, 65°C, or 70°C, but is not limited to the values ​​mentioned above.

[0061] In operation S2, the mixture is processed through a film-forming process to obtain a polyethylene film, wherein the film-forming process is blown film.

[0062] In some embodiments, the film-making process includes: directly feeding the mixture into a PE single-screw extruder, feeding from the feed port at the beginning of the screw, conveying through the screw, extruding and blow molding through the die (single-layer or multi-layer co-extrusion), cooling and forming with an air ring, pressing with herringbone plates, conveying through guide rollers, printing, slitting and winding, cutting to length, and packaging to obtain a polyethylene film (<30μm). The barrel temperature of the single-screw extruder is set to 175~210℃, and the die temperature is set to 200~210℃.

[0063] The polyethylene film prepared using this highly dispersed polyethylene-based resin composition has a uniform appearance, without persistent discolored patches or streaks, and is less prone to local defects caused by filler agglomeration, thus significantly improving its service life when exposed.

[0064] According to an exemplary embodiment of the present invention, the present invention provides a polyethylene film obtained by the above-described preparation method, the polyethylene film comprising a single-layer polyethylene film or a multi-layer co-extruded polyethylene film.

[0065] In some embodiments, the thickness of the polyethylene film is less than or equal to 30 μm, for example, it can be 10 μm, 20 μm, or 30 μm, but is not limited to the values ​​mentioned above.

[0066] In the embodiments of this invention, compared to polyethylene terephthalate (PET), traditional high-barrier materials such as polyamide (PA) and polyvinyl alcohol (EVOH), their processing temperature ranges differ significantly from PE, making it difficult to construct a direct blending system through compatibilization treatment. The non-crystalline properties of PETG and its overlapping processing temperature range with PE, as provided in this application, eliminate the need for pre-granulation, allowing direct blending and molding using a PE single-screw extruder. The low addition of dispersants and compatibilizers provides a significant cost advantage. The impact on the density and melt index of the PE resin matrix is ​​minimized, ensuring the strength and toughness of the molded PE products. Furthermore, the high consideration of processing stability significantly enhances its industrial application value.

[0067] Based on the polyethylene-based resin composition of this invention, single-layer or multi-layer non-transparent PE packaging films (agricultural films, garbage bags, roll masks, etc.) or PE functional films (barrier films, flame-retardant films, vapor-permeable films, etc.) with uniform appearance can be developed. This invention is highly effective for film products and is also applicable to other molded products (sheets, pipes, injection molded products, etc.) based on inorganic-filled PE resin systems.

[0068] According to an exemplary embodiment of the present invention, the present invention provides a composite bitumen waterproof membrane, comprising the aforementioned polyethylene film.

[0069] The following illustrative description illustrates the designed polyethylene-based resin composition, polyethylene film, its preparation method, and applications. It should be noted that these examples are merely specific embodiments of the present invention and do not limit the scope of protection of the present invention.

[0070] Example 1

[0071] Prepare a mixture of polyethylene-based resin compositions.

[0072] Specifically, 65 parts of high-density polyethylene (HDPE), 5 parts of medium-density polyethylene (MDPE), 5 parts of linear low-density polyethylene (LLDPE), 5 parts of polyethylene terephthalate-1,4-cyclohexanediol resin (PETG), 5 parts of glycidyl methacrylate grafted polyethylene (PE-g-GMA), 12 parts of PE calcium masterbatch (221 from Fine Calcium Industry), 6 parts of PE carbon black masterbatch (PE2772 from Cabot), and 1 part of PE defoaming masterbatch (DM-1118 from Luxin Environmental Protection) were put into a high-speed mixer and mixed at high speed at 60°C for 2 hours to obtain a polyethylene resin composition mixture.

[0073] Prepare polyethylene-based films (also known as ultra-thin hot melt masks).

[0074] Specifically, the polyethylene-based resin composition mixture obtained above is directly fed into a PE single-screw extruder. The material is fed from the feed port at the beginning of the screw, and then conveyed by the screw, extruded through the die for blow molding (single layer), cooled by the air ring, pressed with herringbone plates, conveyed by guide rollers, printed, slit and wound, cut to length, and packaged to obtain an ultra-thin hot-melt film (10μm thick). The barrel temperature of the single-screw extruder is set to 175-210℃, and the die temperature is set to 200-210℃.

[0075] Example 2

[0076] Polyethylene-based films were prepared using the same method as in Example 1, except that the proportions of the components were different, as shown in Table 1.

[0077] Example 3

[0078] Polyethylene-based films were prepared using the same method as in Example 1, except that the proportions of the components were different, as shown in Table 1.

[0079] Example 4

[0080] Polyethylene-based films were prepared using the same method as in Example 1, except that the proportions of the components were different, as shown in Table 1.

[0081] Comparative Example 1

[0082] Polyethylene-based films were prepared using the same method as in Example 1, except that the proportions of the components were different, as shown in Table 1.

[0083] Comparative Example 2

[0084] Polyethylene-based films were prepared using the same method as in Example 1, except that the proportions of the components were different, as shown in Table 1.

[0085] Comparative Example 3

[0086] Polyethylene-based films were prepared using the same method as in Example 1, except that the proportions of the components were different, as shown in Table 1.

[0087] Comparative Example 4

[0088] Polyethylene-based films were prepared using the same method as in Example 1, except that the proportions of the components were different, as shown in Table 1.

[0089] Table 1

[0090]

[0091] The calcium powder content of the ultrathin hot-melt films prepared in Examples 1-4 and Comparative Examples 1-4 was tested. The calcium powder content was measured at three randomly selected locations (location 1, location 2, and location 3) on the ultrathin hot-melt films. The ultrathin hot-melt films prepared in Examples 1-4, Comparative Examples 1, and Comparative Examples 4 were applied to composite asphalt waterproof membranes, and the artificial weathering cracking time of the composite asphalt waterproof membranes was tested. The test results are shown in Table 2.

[0092] The calcium powder content test for ultra-thin hot-melt masks includes: cutting a film sample of more than 5 mg, inserting it into an alumina crucible, and sending it into a thermogravimetric analyzer (TGA). In an air / oxygen atmosphere, the temperature is raised from room temperature to 800℃ at a rate of 10℃ / min. The remaining weight percentage is the weight percentage of calcium oxide (wt% [CaO]) generated from the decomposition of calcium carbonate. The calcium powder content (wt% [CaCO3]) can be obtained by reversing the weight percentage of calcium oxide, i.e.: wt% [CaCO3] = wt% [CaO] × 100 / 56.

[0093] The artificial weathering cracking time after the ultra-thin hot melt film is applied to the composite bitumen waterproof membrane shall be determined in accordance with the provisions of 7.19 in GB 18242-2025 "Elastomer / Plastic Modified Bitumen Waterproof Membrane".

[0094] Table 2

[0095]

[0096] Figure 2 This is a physical image of the polyethylene film prepared in Comparative Example 2.

[0097] See Figure 2 As shown, the polyethylene film prepared in Comparative Example 2 has holes.

[0098] Figure 3A This is a photograph of the blown film process in Comparative Example 3.

[0099] Figure 3B This is a photograph of the polyethylene film prepared in Comparative Example 3.

[0100] See Figure 3A As shown, holes occurred during the blown film process in Comparative Example 3. The polyethylene film prepared in Comparative Example 3 exhibited obvious hard lumps.

[0101] Figure 4A This is a physical image of the polyethylene film prepared in Comparative Example 1.

[0102] Figure 4B This is a photograph of the polyethylene film prepared in Example 1.

[0103] See Figure 4A As shown, the surface of the polyethylene film prepared in Comparative Example 1 is uneven. (See also...) Figure 4B As shown, the polyethylene film prepared in Example 1 has a smooth surface and no obvious cracking, indicating that the inorganic filler is uniformly dispersed in the polyethylene film. This is because the addition of PETG in Example 1, along with the use of PE-g-GMA and PE defoaming masterbatch, can improve the uniformity of inorganic filler dispersion in PE resin, avoid local filler agglomeration and excessive content leading to premature film cracking, and significantly extend the exposed service life of the ultra-thin hot melt film after application in composite asphalt waterproof membrane.

[0104] Figures 5A-5B This is a photograph of the actual object showing the fluctuations that occurred during the blown film process in Comparative Example 4.

[0105] See Figure 5A , Figure 5B As shown, Comparative Example 4 exhibited significant fluctuations during the blown film process.

[0106] Figure 6A This is a photograph of the composite bitumen waterproof membrane, including the polyethylene film of Example 1, in its untreated state.

[0107] Figure 6B This is a photograph of a composite bituminous waterproof membrane, including the polyethylene film of Example 1, after artificial weathering treatment.

[0108] refer to Figure 6A , Figure 6B As shown, the polyethylene film of Example 1 was applied to a composite asphalt waterproof membrane. In its untreated state, the composite asphalt waterproof membrane had a smooth surface and no obvious cracking. After 43 hours of artificial post-weathering treatment, cracking appeared in the composite asphalt waterproof membrane.

[0109] As can be seen from Example 3 and Comparative Example 2, Comparative Example 2 does not contain PE defoaming masterbatch, and the polyethylene film obtained in Comparative Example 2 has holes; Example 3 contains PE defoaming masterbatch, and the polyethylene film blowing process in Example 3 is stable and does not fluctuate, and the inorganic filler in the prepared polyethylene film is uniformly dispersed. In other words, Example 3, by adding PE defoaming masterbatch, can solve the problem of water bubble holes caused by the moisture absorption of PETG.

[0110] Based on Examples 2 and 3, it can be seen that Comparative Example 3, which does not contain PE-g-GMA, exhibited holes and lumps during the polyethylene film blowing process; Example 2, which contains PE-g-GMA, showed stable polyethylene film blowing without fluctuations. This indicates that the polyethylene film of Example 2 solved the problems of holes (caused by stretching during the blowing process) and incompatible lumps caused by incompatibility between PETG and PE resin when the PETG content is high by introducing GMA-grafted ethylene polymer resin.

[0111] As shown in Example 2 and Comparative Example 4, Comparative Example 4, using PE-g-MAH as a compatibilizer, experienced membrane bubble instability and fluctuations during the blown film process. Example 2, using PE-g-GMA as a compatibilizer, exhibited a stable blown film process. Compared to Comparative Example 4, Example 2 avoided the problem of MAH easily catalyzing the hydrolysis of PETG ester groups, reducing thermal stability, leading to localized degradation, and consequently causing membrane bubble instability.

[0112] Compared to Example 3, the amounts of calcium powder and carbon black added in Example 4 were reduced, and the amount of PETG added to improve the compatibility of inorganic fillers with PE was also reduced accordingly. Because the amount of PETG added was reduced, its impact on processing stability was decreased, thus eliminating the need to add PE defoaming masterbatch. Furthermore, due to the reduced amount of carbon black added, the artificial weathering cracking time of the hot-melt film applied to the composite asphalt waterproof membrane in Example 4 was also reduced compared to Example 3, because the effect of carbon black in improving UV aging resistance was weakened.

[0113] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyethylene-based resin composition, characterized in that, By weight, including: 50-95 parts polyethylene resin, 0.5-15 parts polyethylene terephthalate-1,4-cyclohexanediol ester resin, and 1-30 parts additives containing inorganic fillers, wherein the inorganic fillers include calcium powder and carbon black.

2. The polyethylene-based resin composition according to claim 1, characterized in that, The weight ratio of polyethylene resin to polyethylene terephthalate-1,4-cyclohexanediol resin is 1:(0.005~0.25).

3. The polyethylene-based resin composition according to claim 1, characterized in that, The intrinsic viscosity of polyethylene terephthalate-1,4-cyclohexanediethanol ester resin is less than 1.0 dL / g, the end carboxyl group content is less than or equal to 35 mol / ton, and the diethylene glycol content is less than or equal to 1.5%.

4. The polyethylene-based resin composition according to claim 1, characterized in that, The inorganic filler also includes calcium oxide; Preferably, the additive containing inorganic fillers includes at least one of the following: 0.5 to 20 parts of polyethylene masterbatch filled with calcium powder are used as filler; 0.5 to 10 parts of carbon black-filled polyethylene masterbatch are used as an anti-aging agent; 0.1 to 5 parts of polyethylene masterbatch filled with calcium oxide are used as defoamers.

5. The polyethylene-based resin composition according to claim 4, characterized in that, The calcium powder in the calcium-filled polyethylene masterbatch has a particle size of 300-3000 mesh, and the calcium powder accounts for more than 80% of the total weight of the calcium-filled polyethylene masterbatch. The carbon black in the carbon black-filled polyethylene masterbatch has a particle size of 300-3000 mesh, and the carbon black accounts for more than 40% of the weight of the carbon black-filled polyethylene masterbatch. The calcium oxide in the calcium oxide-filled polyethylene masterbatch has a particle size of 300-3000 mesh, and the calcium oxide accounts for more than 40% of the weight of the calcium oxide-filled polyethylene masterbatch.

6. The polyethylene-based resin composition according to claim 1, characterized in that, Polyethylene resins include one or more of high-density polyethylene, medium-density polyethylene, and linear low-density polyethylene; High-density polyethylene accounts for more than 50% of the weight of polyethylene resin.

7. The polyethylene-based resin composition according to claim 1, characterized in that, It also includes 0-5 parts of compatibilizer; The compatibilizer includes an epoxy-modified ethylene polymer resin; The epoxy-modified ethylene polymer resin includes at least one of glycidyl methacrylate-grafted polyethylene and glycidyl methacrylate-grafted polyolefin elastomer.

8. A method for preparing a polyethylene film, characterized in that, include: The polyethylene-based resin composition as described in any one of claims 1 to 7 is mixed at a temperature of 50°C to 70°C to obtain a mixture, wherein the mixing time is greater than 1 hour; The mixture is processed through a film-forming process to obtain a polyethylene film, wherein the film-forming process is blown film.

9. A polyethylene film obtained by the preparation method according to claim 8, characterized in that, The polyethylene film includes a single-layer polyethylene film or a multi-layer co-extruded polyethylene film.

10. A composite bituminous waterproof membrane, characterized in that, Includes the polyethylene film as described in claim 9.

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