Process for the preparation of a high density polyethylene speciality resin composition for self-adhesive pre-preg waterproofing membranes

Abstract

The application relates to a preparation method of a high-density polyethylene special resin composition for self-adhesive type pre-laid waterproof coiled material, wherein the molar ratio of 1-hexene to ethylene is controlled to be 0.01-0.15:1 at the beginning of the reaction under the reaction temperature of 83-85 DEG C and the reaction pressure of 2.0-2.2 MPa, the reaction stays for 4-8 hours, the initial product obtained under the conditions of 190 DEG C and 2.16 kg has the melt flow rate of 1-3.5 g / 10 min and the density of 0.910-0.918 g / cm 3 , the addition amount of 1-hexene is gradually reduced, and finally the high-density polyethylene obtained under the conditions of 190 DEG C and 2.16 kg has the melt flow rate of 1-3.5 g / 10 min and the density of 0.938-0.942 g / cm 3 ; the high-density polyethylene is mixed and granulated with an auxiliary to obtain the high-density polyethylene resin composition.

Description

Technical Field

[0001] This invention belongs to the field of polyethylene resin, and specifically relates to a method for preparing a high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane. Background Technology

[0002] Waterproof membranes, serving as the leak-proof connection between the foundation and the building structure, are the first line of defense in waterproofing the entire project and play a crucial role. Waterproof membranes are mainly divided into polymer-modified bitumen-based waterproof membranes (SBS) and synthetic polymer waterproof membranes. Currently, SBS has the highest market share, around 80%, while polymers and other types of waterproof materials each account for about 10%. Polymer waterproof membranes have emerged as a leading force in the waterproofing materials field in recent years due to their numerous advantages, including environmental friendliness, good low-temperature flexibility, high elongation, corrosion resistance, aging resistance, cold application with fast construction speed, and strong decorative properties. Among the four main types of polymer waterproof membranes, EPDM has a complex processing process, large investment scale, and low construction efficiency; PVC and other types have seen reduced usage due to environmental policies; TPO polymer-grade special materials have high technical difficulty and low production volume; and blended grades have poor weather resistance and short lifespan. Therefore, HDPE waterproof membranes are attracting more attention, and their development potential is gradually emerging. HDPE waterproof membrane consists of three parts: HDPE sheet, self-adhesive film, and granular anti-adhesive layer. It is suitable for pre-laying construction and can form an interpenetrating bond with concrete during construction, so that the membrane and the building structure are sealed to the maximum extent, resulting in excellent waterproof and anti-water leakage effects. It has many advantages such as good puncture resistance, high construction efficiency, and strong adaptability to substrate deformation. It is mainly used in many waterproofing fields such as industrial and civil buildings, rail transit, and underground integrated pipe corridors. It is also being gradually applied in new urban structures that extend underground. It is known as the "new generation" of polymer waterproof membrane and its development momentum is very rapid.

[0003] HDPE waterproof membranes are mostly used in national infrastructure projects where concrete is the main building material, such as subway construction, highway tunnels, and residential buildings. Water seepage and leakage are the most fatal damages to concrete structures, potentially leading to a shortened lifespan of the project and serious public hazards. Therefore, in 2017, the Chinese government issued the stringent standard GB / T23457-2017 for HDPE waterproof membranes, imposing strict requirements on the sampling and testing of the main mechanical properties of waterproof membranes, and further increasing the requirements for HDPE raw materials, especially puncture resistance.

[0004] In existing technologies, the main material of polymer rolls is processed by blending various types of special resins such as high-density polyethylene and linear low-density polyethylene to improve the puncture resistance and toughness of the rolls. However, this process suffers from problems such as large fluctuations in processing performance, poor batch quality stability of rolls, higher costs due to thicker sheets, and unstable product performance.

[0005] Patent CN 110283371 A discloses a novel HDPE pre-laid waterproof membrane and its preparation method. This invention discloses a novel HDPE pre-laid waterproof membrane composed of 45%-55% high-density polyethylene, 39%-45% low-density polyethylene, 5.5%-9% polyethylene-olefin copolymer, 0.4%-0.7% antioxidant, and 0.1%-0.3% UV stabilizer. The invention also discloses a method for preparing the novel HDPE pre-laid waterproof membrane. The drawback of this technology is that it uses polyethylene with different performance indicators, directly blending and granulating them into sheets during the waterproof membrane processing. Due to the influence of the different polyethylene states under strong shear conditions, the batch stability and processing performance of the membrane are unstable, leading to inconsistent quality, especially unstable puncture resistance.

[0006] Patent CN 106519420 A discloses a root-penetration-resistant metallocene polyethylene sheet, a self-adhesive roll, and a preparation method thereof. The sheet's base material comprises the following raw materials in parts by weight: metallocene polyethylene resin: 70-80 parts, EVA resin: 10-20 parts, antioxidant: 0.2-0.5 parts, carbon black resin: 2-3 parts, and reinforcing agent: 5-10 parts. The sheet and roll described in this invention have good waterproofing performance and good root-penetration resistance, making them suitable for roof waterproofing projects with high puncture resistance requirements. The drawback of this technology is that the selected metallocene polyethylene resin requires the addition of flexible resin and reinforcing agents to improve strength and flexibility. Furthermore, when processing waterproof rolls with various types of resins, they need to be blended and granulated again to form sheets, which makes it difficult to guarantee product quality stability, especially puncture resistance.

[0007] Patent CN 109130400 B discloses an HDPE polymer self-adhesive waterproof membrane and its manufacturing process. The waterproof membrane includes a polymer sheet, a fabric, and a release liner. Self-adhesive material is filled between the polymer sheet and the fabric, and between the fabric and the release liner. The polymer sheet comprises 45%-50% high-density polyethylene, 5%-10% linear low-density polyethylene, 18%-25% modifier, 20%-25% light calcium carbonate, 3%-5% titanium dioxide, and 0.5%-1% antioxidant. The manufacturing process includes: a) raw material premixing; b) extrusion molding; c) composite fabric; d) filling a protective layer; e) composite release liner; and f) roll winding. The membrane manufactured using this process possesses the high toughness of high-density polyethylene, the high strength of linear low-density polyethylene, and further reinforcement from the modifier, thereby improving the mechanical properties of the waterproof membrane and extending its service life. The drawback of this technology is that the polymer sheets are processed by blending polyethylene of different densities to provide good strength and toughness. The quality of the rolls is affected by the quality of the single type of polyethylene, and the quality stability cannot be guaranteed.

[0008] Patent CN 107962844 B discloses a polymer composite waterproof membrane and its preparation method. This invention is composed of, from top to bottom, a thermoplastic polyolefin waterproof membrane layer, a high-density polyethylene waterproof membrane layer, a polyvinyl chloride (PVC) waterproof membrane layer, a hot melt adhesive layer, and a release film layer. It fully utilizes the characteristics of each of the thermoplastic polyolefin, high-density polyethylene, and PVC waterproof membrane layers, while effectively mitigating and compensating for their respective defects. The preparation process is simple; polyethylene grafting material and tackifying masterbatch are added to the high-density polyethylene and thermoplastic polyolefin waterproof membrane formulations to increase their compatibility and adhesion with the PVC waterproof membrane. The three membrane layers are tightly bonded, resulting in a polymer composite waterproof membrane with higher overall performance, ensuring that water cannot flow within the system. It has stronger applicability, a wider range of applications, saves on pre-construction work, eliminates the need for extensive data matching research, and saves costs. This method involves composite materials made of multiple layers of sheets. To ensure stability between the layers, a large amount of colloid needs to be added between each layer. This results in poor hygiene, environmental friendliness, and quality stability, especially when used indoors.

[0009] Patent CN 111826102 A discloses a modified HDPE waterproof membrane, which comprises, from top to bottom, an isolation layer, an adhesive layer, a protective layer, and a substrate layer. The substrate layer, by weight, comprises the following raw material components: 90-95 parts high-density polyethylene, 1.5-1.8 parts silica, 0.4-0.5 parts antioxidant, 0.8-1 parts flame retardant, and 0.8-1 parts stabilizer. The modified HDPE waterproof membrane exhibits high mechanical strength, good low-temperature resistance, and good flame retardant properties. This invention primarily improves the performance of the HDPE waterproof membrane, such as peel strength, tensile strength, tear strength, and low-temperature resistance, through multi-layer composite methods, but does not significantly improve puncture resistance.

[0010] The self-adhesive pre-laid waterproof membranes mentioned above are all produced by blending one or more of the following materials: high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ethylene-olefin copolymer, or by multi-layering several of the above materials. The quality of the membrane is affected by the quality of the individual materials, and the batch quality stability cannot be guaranteed. The core properties of the products, such as tensile properties and puncture resistance, vary greatly. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a method for preparing a high-density polyethylene resin composition for self-adhesive pre-laid waterproof membranes.

[0012] The present invention provides a method for preparing a high-density polyethylene resin composition for self-adhesive pre-laid waterproof membrane. The method employs a gas-phase production process and a metallocene catalyst to prepare an ethylene-hexene copolymer. Specifically, the preparation steps are as follows: The reaction is carried out at a reaction temperature of 83-85℃ and a reaction pressure of 2.0-2.2 MPa for 4-8 hours. The initial molar ratio of 1-hexene to ethylene is controlled at 0.01-0.15:1. This yields a melt flow rate of 1-3.5 g / 10 min and a density of 0.910-0.918 g / cm³ at 190℃ and 2.16 kg. 3 After the initial product was obtained, the amount of 1-hexene added was gradually reduced, eventually yielding a melt flow rate of 1-3.5 g / 10 min and a density of 0.938-0.942 g / cm³ at 190℃ and 2.16 kg. 3 High-density polyethylene; high-density polyethylene is mixed with additives and granulated to obtain a high-density polyethylene resin composition.

[0013] The preparation method of the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to the present invention involves gradually reducing the amount of 1-hexene added. The specific process is as follows: first, the amount of 1-hexene added is reduced to 80-90% of the initial amount; then, every 1-1.5 hours, it is reduced to 80-90% of the previous amount, until the reaction time exceeds half of the residence time. At this point, the addition of 1-hexene is stopped, and the reaction temperature and pressure are kept constant, continuing the reaction until the end of the reaction cycle.

[0014] The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to the present invention is wherein the molecular weight of the high-density polyethylene is normally distributed, and the molecular weight is distributed between 2.0 and 3.0, preferably between 2.5 and 3.0.

[0015] The preparation method of the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane of the present invention has the following characteristics: reaction temperature is 83-84℃, preferably 83.5℃; reaction pressure is 2.1MPa, preferably 2.05MPa; and reaction residence time is 6-8h.

[0016] The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane of the present invention has a molar ratio of 1-hexene to ethylene of 0.01-0.10:1, preferably 0.01-0.05:1, in the initial stage of the reaction.

[0017] The method for preparing the high-density polyethylene resin composition for self-adhesive pre-laid waterproof membrane according to the present invention has the following initial product: melt flow rate of 1-2.5 g / 10 min and density of 0.910-0.915 g / cm³ at 190°C and 2.16 kg. 3 Preferably, the melt flow rate is 1-2.0 g / 10 min and the density is 0.910-0.912 g / cm³. 3 .

[0018] The preparation method of the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane of the present invention involves gradually reducing the amount of 1-hexene added. The specific process is as follows: first, the amount of 1-hexene added is reduced to 85-90% of the initial amount, and then reduced to 85-90% of the previous amount every 1-1.5 hours until the reaction time exceeds half of the residence time. Then, the addition of 1-hexene is stopped, the reaction temperature and pressure are kept constant, and the reaction continues until the end of the reaction cycle.

[0019] The method for preparing the high-density polyethylene (HDPE) resin composition for self-adhesive pre-laid waterproof membrane according to the present invention specifies that the melt flow rate of HDPE at 190°C and 2.16 kg is 1-2.5 g / 10 min, preferably 1.5-2.0 g / 10 min, and the density is 0.939-0.941 g / cm³. 3 .

[0020] The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to the present invention has a mass ratio of high-density polyethylene to additives of 100:0.2-0.5, preferably 100:0.3-0.4, and more preferably 100:0.4.

[0021] The present invention discloses a method for preparing a high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane, wherein the additives are a mixture of phenolic antioxidants, lactone auxiliary antioxidants, stabilizers and fluorinated processing aids in a mass ratio of 1:0.5-2:0.1-1:0.01-0.5, preferably 1:1-1.5:0.5-0.7:0.1-0.2.

[0022] The metallocene catalyst used in this invention is a commonly used catalyst in the field. No special limitation is made on the catalyst. Ordinary commercial products or those prepared by conventional preparation methods in the field can be used.

[0023] Beneficial effects of this invention:

[0024] (1) The high-density polyethylene product produced by the present invention using a gas phase reactor and metallocene catalyst is directly synthesized by flexible ultra-low density polyethylene and rigid high-density polyethylene during the reaction process. The product has stable quality and uniform performance. The high-density polyethylene produced has advantages such as good flexibility, good puncture resistance, high strength and good processing performance.

[0025] (2) The 1-hexene decrement control technology used in this invention completes the production of the target product within a residence time. By adjusting the amount of 1-hexene, the activity release of the metallocene catalyst is effectively stimulated. It operates stably in industrial equipment and is highly operable.

[0026] (3) The self-adhesive pre-laid waterproof membrane prepared by the present invention has a simple processing technology, uniform membrane thickness, good batch quality stability, does not require the addition of multiple adhesives, is hygienic and environmentally friendly, and has good application prospects in the field of waterproof membrane. Detailed Implementation

[0027] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0028] Catalyst preparation:

[0029] Silica gel was activated at 600℃ for 8 hours, and then pretreated with MAO (methylaluminoxane) at 100℃. The metallocene compound (bis(1-ethyl-2-methylcyclopentadienyl)zirconia dichloride), MAO, and the pretreated silica gel were reacted at 45℃ for 4 hours. The product was filtered, washed with toluene, and dried to obtain a supported metallocene catalyst with zirconium as the active center and a catalytic activity of approximately 8000 gPE / gCat.

[0030] Example 1

[0031] Using a gas-phase production process, the metallocene catalyst prepared by the above method was controlled at a reaction temperature of 83℃, a reaction pressure of 2.1 MPa, a residence time of 6 hours, and an initial molar ratio of 1-hexene to ethylene of 0.05:1. The resulting product had a melt flow rate (190℃, 2.16 kg) of 2.5 g / 10 min and a density of 0.910 g / cm³. 3 After reacting for 1 hour, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.0425:1. After reacting for 2 hours, the amount of 1-hexene added was further reduced to a molar ratio of 1-hexene to ethylene of 0.036:1. After reacting for 3 hours, the amount of 1-hexene added was further reduced to a molar ratio of 1-hexene to ethylene of 0.0306:1. After reacting for 4 hours, the addition of 1-hexene was stopped, and the reaction temperature and pressure were kept constant. The reaction was continued for another 2 hours, resulting in a melt flow rate (190℃, 2.16 kg) of 2.5 g / 10 min and a density of 0.940 g / cm³. 3 Polymer products.

[0032] The polymer and composite additives were granulated in the granulation section at a mass ratio of 100:0.3. The composite additives consisted of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], tris(2,4-di-tert-butylphenyl) phosphite, calcium stearate, and fluorinated processing aid (3M, FX5911) in a ratio of 1:1:0.5:0.2. The resulting high-density composite product had a melt flow rate (190°C, 2.16 kg) of 2.5 g / 10 min and a density of 0.940 g / cm³. 3 .

[0033] Example 2

[0034] Using a gas-phase production process, the metallocene catalyst prepared by the above method was controlled at a reaction temperature of 83℃, a reaction pressure of 2.0 MPa, a residence time of 8 hours, and an initial molar ratio of 1-hexene to ethylene of 0.1:1. The resulting product had a melt flow rate (190℃, 2.16 kg) of 2.0 g / 10 min and a density of 0.918 g / cm³. 3 After 2 hours of reaction, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.085:1. After 3 hours of reaction, the molar ratio of 1-hexene added was reduced to 0.072:1. After another 3 hours, the molar ratio of 1-hexene added was reduced to 0.061:1. After 4 hours of reaction, the molar ratio of 1-hexene added was reduced again to 0.052:1. After 4.5 hours of reaction, the addition of 1-hexene was stopped, and the reaction was continued for another 3.5 hours while maintaining constant temperature and pressure. The resulting melt had a flow rate (190℃, 2.16 kg) of 2.5 g / 10 min and a density of 0.940 g / cm³. 3 Polymer products.

[0035] The polymer and composite additives were granulated in the granulation section at a mass ratio of 100:0.3. The composite additives consisted of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], tris(2,4-di-tert-butylphenyl) phosphite, calcium stearate, and fluorinated processing aid (3M, FX5911) in a ratio of 1:1:0.5:0.2. The resulting high-density composite product had a melt flow rate (190°C, 2.16 kg) of 2.5 g / 10 min and a density of 0.940 g / cm³. 3 .

[0036] Example 3

[0037] Using a gas-phase production process, the metallocene catalyst prepared by the above method was controlled at a reaction temperature of 83.5℃, a reaction pressure of 2.0 MPa, a residence time of 8 hours, and an initial molar ratio of 1-hexene to ethylene of 0.1:1. The resulting product had a melt flow rate (190℃, 2.16 kg) of 2 g / 10 min and a density of 0.915 g / cm³. 3After reacting for 1 hour, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.085:1. After reacting for 2 hours, the molar ratio of 1-hexene added was reduced to 0.072:1. After reacting for 3 hours, the molar ratio of 1-hexene added was reduced to 0.061:1. After reacting for 4 hours, the molar ratio of 1-hexene added was further reduced to 0.052. After reacting for 6 hours, the addition of 1-hexene was stopped, and the reaction temperature and pressure were kept constant. The reaction was continued for another 2 hours, resulting in a melt flow rate (190℃, 2.16 kg) of 2.0 g / 10 min and a density of 0.939 g / cm³. 3 Polymer products.

[0038] The polymer and composite additives were granulated in the granulation section at a mass ratio of 100:0.3. The composite additives consisted of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], tris(2,4-di-tert-butylphenyl) phosphite (a lactone-based auxiliary antioxidant), calcium stearate (a stabilizer), and fluorinated processing aid (3M, FX5911) in a ratio of 1:1:0.5:0.2. The resulting high-density composite product had a melt flow rate (190°C, 2.16 kg) of 2.0 g / 10 min and a density of 0.939 g / cm³. 3 Polymer products.

[0039] Example 4

[0040] Using a gas-phase production process, the metallocene catalyst prepared by the above method was controlled at a reaction temperature of 83.5℃, a reaction pressure of 2.0 MPa, a residence time of 6 hours, and an initial molar ratio of 1-hexene to ethylene of 0.05:1. The resulting product had a melt flow rate (190℃, 2.16 kg) of 3.5 g / 10 min and a density of 0.918 g / cm³. 3 After reacting for 1 hour, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.045:1. After reacting for 2 hours, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.041. After reacting for 3 hours, the amount of 1-hexene added was further reduced to a molar ratio of 1-hexene to ethylene of 0.036. After reacting for 5 hours, the addition of 1-hexene was stopped, and the reaction temperature and pressure were kept constant. The reaction was continued for another hour, resulting in a melt flow rate (190℃, 2.16 kg) of 1.5 g / 10 min and a density of 0.942 g / cm³. 3 Polymer products.

[0041] The polymer and composite additives were granulated in the granulation section at a mass ratio of 100:0.3. The composite additives consisted of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl)phosphite, calcium stearate, and fluorinated processing aid (3M, FX5911) in a ratio of 1:1:0.5:0.2. The resulting high-density composite product had a melt flow rate (190°C, 2.16 kg) of 1.5 g / 10 min and a density of 0.942 g / cm³. 3 .

[0042] Example 5

[0043] Using a gas-phase production process, the metallocene catalyst prepared by the above method was controlled at a reaction temperature of 83.5℃, a reaction pressure of 2.2 MPa, a residence time of 4 hours, and a molar ratio of 1-hexene to ethylene of 0.01:1. The resulting product had a melt flow rate (190℃, 2.16 kg) of 3.0 g / 10 min and a density of 0.910 g / cm³. 3 After reacting for 1 hour, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.009:1. After reacting for 2 hours, the amount of 1-hexene added was further reduced to a molar ratio of 1-hexene to ethylene of 0.008:1. After reacting for 3 hours, the addition of 1-hexene was stopped, and the reaction temperature and pressure were kept constant. The reaction was continued for another hour, resulting in a melt flow rate (190℃, 2.16 kg) of 3.0 g / 10 min and a density of 0.941 g / cm³. 3 Polymer products.

[0044] The polymer and composite additives were granulated in the granulation section. The mass ratio of polymer to composite additives was 100:0.3. The composite additives consisted of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], a lactone-based auxiliary antioxidant, tris(2,4-di-tert-butylphenyl) phosphite, a stabilizer, calcium stearate, and a fluorinated processing aid (a mixture of vinylidene fluoride and hexafluoropropylene, such as 3M's FX5911), in a ratio of 1:1:0.5:0.2. The resulting high-density composite product had a melt flow rate (190°C, 2.16 kg) of 3.0 g / 10 min and a density of 0.941 g / cm³. 3 .

[0045] Example 6

[0046] Using a gas-phase production process, the metallocene catalyst prepared by the above method was controlled at a reaction temperature of 85℃, a reaction pressure of 2.1 MPa, a residence time of 8 hours, and a molar ratio of 1-hexene to ethylene of 0.15:1. The resulting product had a melt flow rate (190℃, 2.16 kg) of 3.5 g / 10 min and a density of 0.910 g / cm³. 3 After reacting for 1.5 hours, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.135:1. After reacting for 2.5 hours, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.122:1. After reacting for 3.5 hours, the amount of 1-hexene added was reduced to a molar ratio of 1-hexene to ethylene of 0.109:1. After reacting for 4.5 hours, the amount of 1-hexene added was further reduced to a molar ratio of 1-hexene to ethylene of 0.098:1. After reacting for 6 hours, the addition of 1-hexene was stopped, and the reaction was continued for another 2 hours while keeping other conditions unchanged. The resulting melt had a flow rate (190℃, 2.16 kg) of 1.0 g / 10 min and a density of 0.939 g / cm³. 3 Polymer products.

[0047] The polymer and composite additives were granulated in the granulation section at a mass ratio of 100:0.3. The composite additives consisted of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], tris(2,4-di-tert-butylphenyl) phosphite (a lactone-based auxiliary antioxidant), calcium stearate (a stabilizer), and fluorinated processing aid (3M, FX5911) in a ratio of 1:1:0.5:0.2. The resulting high-density composite product had a melt flow rate (190°C, 2.16 kg) of 1.0 g / 10 min and a density of 0.939 g / cm³. 3 .

[0048] The high-density compositions from Examples 1-6 were made into waterproof membranes with a thickness of 1 mm, and the test results are shown in the table.

[0049] Comparative Example 1

[0050] A high-density ethylene-butene copolymer with a mass ratio of 100:84:14.5:1.1:0.4 (density 0.948-0.952 g / cm³) was prepared. 3 The melt flow rate is 1-2 g / 10 min, and the low-density ethylene-butene copolymer (density is 0.918-0.920 g / cm³) is also mentioned. 3 Melt flow rate of 1-2 g / 10 min), ethylene-hexene copolymer (density of 0.916-0.918 g / cm³). 3The mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 2-hydroxy-4-n-octyloxybenzophenone was extruded and granulated under a twin-screw extruder, and then made into 1 mm rolls by a roll forming equipment to prepare comparative sample 1.

[0051] Comparative Example 2

[0052] A mixture of high-density polyethylene (ethylene-hexene copolymer) with a mass ratio of 90:90:18:1.4:0.6 (density 0.948-0.952 g / cm3, melt flow rate 1-2 g / 10 min), low-density polyethylene (ethylene-butene copolymer) with a density of 0.918-0.920 g / cm3, melt flow rate 1-2 g / 10 min), ethylene-hexene copolymer (density 0.916-0.918 g / cm3, melt flow rate 1-2 g / 10 min), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 2-hydroxy-4-n-octyloxybenzophenone was extruded and granulated under a twin-screw extruder, and then made into 1 mm rolls using a roll forming equipment to prepare comparative sample 2.

[0053] Comparative Example 3

[0054] In a gas-phase apparatus, using the metallocene catalyst prepared by the above method, the reaction temperature was controlled at 83℃, the reaction pressure at 2.0 MPa, the residence time at 8 hours, and the molar ratio of 1-hexene to ethylene was 0.001-0.01:1 with continuous addition. The resulting product had a melt flow rate of 1.5 g / 10 min and a density of 0.940 g / cm³. 3 The polymer and composite additives were granulated in the granulation section. The mass ratio of the polymer to the composite additives was 100:0.3. The composite additives consisted of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], a phenolic antioxidant, tris(2,4-di-tert-butylphenyl) phosphite, a stabilizer, calcium stearate, and a fluorinated processing aid (3M, FX5911) in a ratio of 1:1:0.5:0.2. The above products were then processed into 1mm rolls using a roll forming machine to prepare comparative sample 3.

[0055] Table 1. Analysis and test results of waterproof membrane.

[0056]

[0057] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a high-density polyethylene resin composition for self-adhesive pre-laid waterproof membrane, comprising a gas-phase production process and a metallocene catalyst to prepare an ethylene-hexene copolymer, characterized in that... The specific preparation steps are as follows: The reaction is carried out at a temperature of 83-85℃ and a pressure of 2.0-2.2 MPa for 4-8 hours. The initial molar ratio of 1-hexene to ethylene is controlled at 0.01-0.15:

1. The resulting melt has a flow rate of 1-3.5 g / 10 min and a density of 0.910-0.918 g / cm³ at 190℃ and 2.16 kg. 3 After the initial product was obtained, the amount of 1-hexene added was gradually reduced, eventually yielding a melt flow rate of 1-3.5 g / 10 min and a density of 0.938-0.942 g / cm³ at 190℃ and 2.16 kg. 3 High-density polyethylene; high-density polyethylene is mixed with additives and granulated to obtain a high-density polyethylene resin composition; The specific process of gradually reducing the amount of 1-hexene added is as follows: first, reduce the amount of 1-hexene added to 80-90% of the initial amount, and then reduce it to 80-90% of the previous amount every 1-1.5 hours until the reaction time exceeds half of the residence time. Then, stop adding 1-hexene, keep the reaction temperature and pressure constant, and continue the reaction until the end of the reaction cycle.

2. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The molecular weight of high-density polyethylene follows a normal distribution, ranging from 2.0 to 3.

0.

3. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 2, characterized in that, The molecular weight of high-density polyethylene is between 2.5 and 3.

0.

4. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The reaction temperature is 83-84℃, the reaction pressure is 2.1MPa, and the reaction residence time is 6-8h.

5. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The reaction temperature was 83.5℃.

6. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, In the initial stage of the reaction, the molar ratio of 1-hexene to ethylene is 0.01-0.10:

1.

7. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, In the initial stage of the reaction, the molar ratio of 1-hexene to ethylene is 0.01-0.05:

1.

8. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The initial product exhibited a melt flow rate of 1-2.5 g / 10 min and a density of 0.910-0.915 g / cm³ under conditions of 190℃ and 2.16 kg. 3 .

9. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The initial product exhibited a melt flow rate of 1-2.0 g / 10 min and a density of 0.910-0.912 g / cm³ under conditions of 190℃ and 2.16 kg. 3 .

10. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The specific process of gradually reducing the amount of 1-hexene added is as follows: first, reduce the amount of 1-hexene added to 85-90% of the initial amount, and then reduce it to 85-90% of the previous amount every 1-1.5 hours until the reaction time exceeds half of the residence time. Then, stop adding 1-hexene, keep the reaction temperature and pressure constant, and continue the reaction until the end of the reaction cycle.

11. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The melt flow rate of high-density polyethylene at 190℃ and 2.16 kg is 1-2.5 g / 10 min, and its density is 0.939-0.941 g / cm³. 3 .

12. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The melt flow rate of high-density polyethylene at 190℃ and 2.16kg is 1.5-2.0g / 10min.

13. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The mass ratio of high-density polyethylene to additives is 100:0.2-0.

5.

14. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The mass ratio of high-density polyethylene to additives is 100:0.3-0.

4.

15. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The mass ratio of high-density polyethylene to additives is 100:0.

4.

16. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The additive is a mixture of phenolic antioxidants, lactone-based auxiliary antioxidants, stabilizers, and fluorinated processing aids in a mass ratio of 1:0.5-2:0.1-1:0.01-0.

5.

17. The method for preparing the high-density polyethylene special resin composition for self-adhesive pre-laid waterproof membrane according to claim 1, characterized in that, The additive is a mixture of phenolic antioxidants, lactone-based auxiliary antioxidants, stabilizers, and fluorinated processing aids in a mass ratio of 1:1-1.5:0.5-0.7:0.1-0.2.

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