High-density polyethylene (HDPE) double-wall corrugated pipe reinforced master batch

Abstract

The invention discloses an HDPE (high-density polyethylene) double-wall corrugated pipe reinforced master batch, which belongs to the technical field of high polymer materials and comprises the following materials in parts by weight: 50-70 parts of UHMWPE (ultrahigh molecular weight polyethylene), 30-40 parts of modified inorganic fiber and 5-10 parts of polyethylene wax. The molecular weight of the UHMWPE is 0.5 to 1.5 million; in the preparation process of the enhanced master batch, the length-diameter ratio of a twin-screw extruder is greater than or equal to 48: 1, and the temperature of an extruded melt is 220-240 DEG C. By adopting an ultra-high molecular weight polyethylene molecular chain entanglement regulation and control technology, an ultra-long molecular chain of UHMWPE is unwound under melt extrusion, the molecular chain is wound on the surface of the modified columnar inorganic fiber, the degree of freedom of the ultra-long molecular chain is constrained and limited, the creep retraction capability of the composite material is reduced, the ring stiffness is greatly improved, and the performance of the composite material is improved. And the impact performance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer composite materials, and in particular relates to a HDPE double-wall corrugated pipe reinforcement masterbatch. Background Art

[0002] Double-wall corrugated pipe is a new type of pipe with an annular outer wall and a smooth inner wall, mainly used for underground drainage and sewage. Since plastic pipes for underground drainage and sewage mainly bear loads from the outside of the pipe, the ring stiffness of the pipe is an important indicator. The higher the ring stiffness, the higher the ability of the pipe to withstand external loads; conversely, the smaller the ring stiffness of the pipe, the lower the ability of the pipe to withstand external loads. At present, the biggest problem of HDPE double-wall corrugated pipe in use is the low ring stiffness, especially large-diameter HDPE double-wall corrugated pipe, which is a technical problem that urgently needs to be studied.

[0003] The ring stiffness of the pipe is related to the elastic modulus of the outer material. At present, the widely used method to improve the ring stiffness of the bellows is to add inorganic fillers or high modulus resins to the outer raw materials. However, the impact strength decreases significantly after adding inorganic fillers to the material, which has a very adverse effect on the transportation and use of the pipe. In addition, patent CN202110685451.3 introduces a method for improving the ring stiffness of HDPE double-wall corrugated pipes. By introducing ultra-high molecular weight polyethylene (UHMWPE) into the outer wall structural material of the bellows, the ring stiffness and wear resistance of the bellows are greatly improved. In fact, ultra-high molecular weight polyethylene can theoretically improve the ring stiffness of double-wall corrugated pipes, but its molecular chain is long and prone to molecular creep, which leads to an increase in the creep ratio of the pipe. When used for a long time, the buried drainage pipe is gradually compressed and deformed, which has an adverse effect on the performance of the pipe. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a HDPE double-wall corrugated pipe reinforcement masterbatch.

[0005] Another object of the present invention is to provide an application of a HDPE double-wall corrugated pipe reinforcement masterbatch in the preparation of a HDPE double-wall corrugated pipe.

[0006] Another object of the present invention is to provide a HDPE double-wall corrugated pipe composition.

[0007] Another object of the present invention is to provide a HDPE double-wall corrugated pipe.

[0008] Another object of the present invention is to provide a method for preparing a HDPE double-wall corrugated pipe.

[0009] Another object of the present invention is to provide an application of a HDPE double-wall corrugated pipe in drainage and sewage treatment.

[0010] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0011] A HDPE double-wall corrugated pipe reinforcement masterbatch, comprising the following components in parts by weight: 50-70 parts of UHMWPE, 30-40 parts of modified inorganic fiber, and 5-10 parts of lubricant;

[0012] The molecular weight of the UHMWPE is 500,000-1.5 million; the length-to-diameter ratio of the twin-screw extruder used in the preparation of the reinforced masterbatch is ≥48:1, and the melt temperature is 220-240°C.

[0013] The present invention adopts the entanglement control technology of ultra-high molecular weight polyethylene molecular chain. In the reinforcing masterbatch, the ultra-long molecular chain of UHMWPE is untangled under the melt extrusion of the twin-screw extruder, and the molecular chain is entangled on the surface of the modified columnar inorganic fiber. The freedom of the ultra-long molecular chain is therefore restricted, reducing the creep shrinkage ability of the composition in the later stage. At the same time, UHMWPE is tightly entangled with the columnar inorganic fiber, so that the impact performance of the composite material is improved.

[0014] Since ultra-high molecular weight polyethylene has an ultra-long linear structure and has molecular chain orientation, the molecular chain deorientation occurs during long-term use and forms creep. Therefore, the molecular chain of UHMWPE is detangled and entangled with the modified inorganic fiber to form a steric hindrance, which limits the molecular chain deorientation of ultra-high molecular weight polyethylene, thereby reducing creep.

[0015] The molecular weight of UHMWPE affects its disentanglement effect. The larger the molecular weight of UHMWPE, the greater its melt viscosity, the slower the flow rate, and the more difficult it is to disentangle. Controlling the molecular weight of UHMWPE between 500,000 and 1.5 million can ensure that UHMWPE is fully disentangled and entangled with the modified inorganic fibers.

[0016] The purpose of controlling the aspect ratio is to solve the plasticization problem of ultra-high molecular weight polyethylene. Controlling the aspect ratio of the twin-screw extruder to ≥48:1 is conducive to the disentanglement of ultra-high molecular weight polyethylene molecules.

[0017] Too high a melt temperature will cause the UHMWPE to degrade, and too low a melt temperature will result in poor disentanglement. Therefore, controlling the melt temperature at 220-240°C can ensure the disentanglement of the UHMWPE and prevent its degradation.

[0018] The melt temperature is measured by the probe provided in the extruder.

[0019] Lubricants can assist in the disentanglement of ultra-high molecular weight polyethylene.

[0020] It should be noted that the molecular weight of UHMWPE in the present invention is mainly based on the viscosity characteristics of its solution and calculated according to the Mark-Houwink equation. The viscosity characteristics of its solution can be measured according to standard ASTM D4020.

[0021] The present invention determines the molecular weight of UHMWPE by solution viscosity measurement, the principle of which is to use the relationship between the viscosity and molecular weight of a polymer solution under specific conditions to determine the molecular weight. The present invention generally uses an Ubbelohde viscometer or an automatic viscosity meter. The specific steps are as follows:

[0022] UHMWPE powder is dissolved in a solvent (such as decahydronaphthalene) to prepare a polymer solution. At a temperature of 135°C, the elution time of the pure solvent and the polymer solution is measured using an Ubbelohde viscometer. The molecular weight of UHMWPE is calculated using the Mark-Houwink equation by calculating the ratio of the solvent elution time to the polymer solution elution time.

[0023] Specifically, the modified inorganic fiber is one or more of glass fiber, basalt fiber, silicon carbide fiber, and alumina fiber.

[0024] Specifically, the modified inorganic fiber is a columnar chopped fiber.

[0025] Specifically, the modified inorganic fibers have an average length of 2-5 mm and an average diameter of 9-15 um.

[0026] The chopped length and fiber diameter of modified inorganic fibers affect processing. If the length is too long or the diameter is too thin, it will be more difficult to feed.

[0027] Preferably, the modified inorganic fiber is a surface silane-grafted modified inorganic fiber.

[0028] Specifically, the preparation method of the modified inorganic fiber comprises the following steps:

[0029] The silane coupling agent is diluted, sprayed onto the surface of the inorganic fiber, and baked to obtain the modified inorganic fiber.

[0030] Silane coupling agent can enhance the lipophilicity of inorganic fiber surface and improve the affinity between inorganic fiber and polymer matrix. Modification of inorganic fiber can ensure that the untangled UHMWPE can be fully entangled with inorganic fiber, thereby constraining the molecular chain freedom of UHMWPE.

[0031] More specifically, the silane coupling agent is at least one of KH550, KH560, KH570, and KH792.

[0032] More specifically, the mass ratio of the silane coupling agent to the inorganic fiber is (0.5-2): 100

[0033] More specifically, the solvent used for the dilution is one or more of methanol, ethanol, and isopropanol.

[0034] More specifically, the mass fraction of the diluted silane coupling agent is 8%-12%.

[0035] More specifically, the baking temperature is 80-100° C., and the baking time is 1-3 hours.

[0036] Preferably, the reinforced masterbatch further comprises 0.2-0.4 parts of an antioxidant.

[0037] Specifically, the antioxidant is one of antioxidant 1010, antioxidant 1790, and antioxidant 1330.

[0038] Specifically, the lubricant is one of polyethylene wax, oxidized polyethylene wax, calcium stearate, and zinc stearate.

[0039] Specifically, the preparation method of the reinforced masterbatch comprises the following steps:

[0040] The raw materials are mixed, extruded into granules through a twin-screw extruder, and dried to obtain a reinforced masterbatch.

[0041] The benefit of preparing the reinforcing masterbatch is that it helps the ultra-high molecular weight polyethylene to fully disentangle and form an entangled organic-inorganic combination with the modified inorganic fiber. After blending with HDPE, the ultra-high molecular weight polyethylene and the modified inorganic fiber can better play a synergistic role. Without this process, the chain entanglement regulation of the ultra-high molecular weight polyethylene cannot be achieved, which will lead to an increase in the creep ratio of the pipe and a decrease in the impact strength.

[0042] More specifically, the screw barrel temperature of the plasticizing section of the twin-screw extruder is 210-230°C, and the screw barrel temperature of the homogenizing section is 200-220°C.

[0043] More specifically, the drying temperature is 60-70° C., and the drying time is 1-3 hours.

[0044] The present invention also protects the use of the HDPE double-wall corrugated pipe reinforcement masterbatch in the preparation of double-wall corrugated pipes.

[0045] A HDPE double-wall corrugated pipe composition, which is an outer wall composition or an inner wall composition. The outer wall composition comprises the following components in parts by weight: 100 parts of HDPE, 100-150 parts of reinforcing masterbatch, and 3-5 parts of masterbatch; the inner wall composition comprises the following components in parts by weight: 100 parts of HDPE, 50-100 parts of reinforcing masterbatch, and 3-5 parts of masterbatch.

[0046] Specifically, the melt flow rate of the HDPE in the outer wall composition or the inner wall composition at 190° C. and 5 kg is less than 1.5 g / 10 min.

[0047] The melt flow rate of HDPE is determined according to standard GB / T 3682-2000.

[0048] The melt flow rate of HDPE affects the impact performance and ring stiffness of the HDPE double-wall corrugated pipe. Therefore, the melt flow rate of HDPE is controlled below 1.5 g / 10 min in the present invention to ensure that the double-wall corrugated pipe has sufficient impact performance and ring stiffness.

[0049] Specifically, the masterbatch has a melt flow rate of 30 to 42 g / 10 min at 190° C. and 21.6 kg.

[0050] The melt flow rate of the masterbatch is measured according to ISO 1133.

[0051] Specifically, the inner wall composition and the outer wall composition further include a defoaming agent.

[0052] More specifically, the inner wall composition includes 2-4 parts of defoaming agent; the outer wall composition includes 2-4 parts of defoaming agent.

[0053] The defoamer is one of an organosilicon type defoamer, a polyether type defoamer, and a polyether modified organosilicon type defoamer.

[0054] The function of the defoaming agent is to eliminate the influence of the gas produced by the decomposition of raw materials on the performance of the double-wall corrugated pipe.

[0055] A HDPE double-wall corrugated pipe, the pipe wall of which comprises an inner wall and an outer wall, the outer wall comprises an outer wall composition, and the inner wall comprises an inner wall composition.

[0056] A method for preparing a HDPE double-wall corrugated pipe comprises the following steps:

[0057] Step 1, mixing the raw materials and transferring them into a single screw extruder to obtain a mixed material;

[0058] Step 2: Melt and extrude the mixed material to obtain a corrugated pipe blank, and shape it to obtain a rough corrugated pipe;

[0059] Step 3: Cool down and cut the crude corrugated pipe to obtain a HDPE double-wall corrugated pipe.

[0060] The wall of the HDPE double-wall corrugated pipe consists of a smooth inner wall and an annular outer wall, which are extruded and fed by two single-screw extruders respectively.

[0061] The present invention also protects the application of the HDPE double-wall corrugated pipe in drainage and sewage treatment.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] The outer wall composition of the HDPE double-wall corrugated pipe of the present invention adopts the ultra-high molecular weight polyethylene molecular chain entanglement control technology, introduces the reinforcing masterbatch into the outer wall, untangles the UHMWPE molecular chain and then winds it on the surface of the modified inorganic fiber, and the UHMWPE is tightly wound and combined with the columnar inorganic fiber. The composition is used to prepare the HDPE double-wall corrugated pipe, thereby improving the ring stiffness of the corrugated pipe, reducing the creep shrinkage ability of the corrugated pipe, and improving the impact performance of the pipe.

[0064] The HDPE double-wall corrugated pipe of the present invention has good ring stiffness, creep performance and drop weight impact performance, and the ring stiffness is ≥16kN / m 2 , drop weight impact performance ≤5%, creep ratio <4. DETAILED DESCRIPTION

[0065] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below through specific examples. The test methods used in the examples and / or comparative examples are conventional methods unless otherwise specified; the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0066] Some of the reagents selected in the embodiments and comparative examples of the present invention are described as follows:

[0067] HDPE: Manufacturer: Sinopec Hainan Refining and Chemical Co., Ltd., brand: 23050, according to the GB / T3682-2000 test method, the melt flow rate at 190°C and 5kg is 0.3g / 10min;

[0068] Masterbatch: Manufacturer: Cabot Corporation, Brand: UN2014, according to ISO 1133 test method, the melt flow rate at 190°C and 21.6kg is 36g / 10min;

[0069] UHMWPE-1: Manufacturer: Mitsui Chemicals, Inc., brand: 030S, molecular weight: 500,000;

[0070] UHMWPE-2: Manufacturer: Korea Petrochemical Corporation, brand: VH150U, molecular weight: 1.5 million;

[0071] UHMWPE-3: Manufacturer: Mitsui Chemicals, Inc., brand: 145M, molecular weight: 1.1 million;

[0072] UHMWPE-4: Manufacturer: Mitsui Chemicals, Inc., brand: 240S, molecular weight: 2 million;

[0073] Glass fiber: Manufacturer: Jushi Group Co., Ltd., Brand: ECS13-03-508A, average fiber length 3.0mm, average diameter 13um;

[0074] Basalt fiber: Manufacturer: Tai'an Anfeng New Material Technology Co., Ltd., brand: AF53, average fiber length 3mm, average diameter 11um;

[0075] Silane coupling agent: KH550; Manufacturer: Zhongshan Dixin Chemical Co., Ltd.;

[0076] Polyethylene wax: Fischer-Tropsch wax 105 degrees, manufacturer: Dalian Hongze Petrochemical Co., Ltd.;

[0077] Antioxidant: Antioxidant 1010; Manufacturer: Tianjin Lianlong Materials Co., Ltd.;

[0078] Defoaming agent: Dow Corning DC65 defoaming agent; Manufacturer: Dow Corning Corporation;

[0079] Unless otherwise specified, the HDPE double-wall corrugated pipes of the embodiments and comparative examples of the present invention are prepared by the following process:

[0080] The preparation method of the modified inorganic fiber is as follows: silane coupling agent KH550 is diluted to a mass fraction of 10% by using 99% ethanol solvent, the diluted solution is evenly sprayed onto the surface of the inorganic fiber through an atomizer, and then baked in a baking oven at 90° C. for 2 hours to obtain the modified inorganic fiber; the mass ratio of the silane coupling agent to the inorganic fiber is 1:100;

[0081] The preparation method of the reinforced masterbatch is as follows: granulation is performed by extrusion through a twin-screw extruder, the aspect ratio of the twin-screw extruder is 48:1, the screw temperature of the plasticizing section of the extruder is 220° C., the screw temperature of the homogenizing section is 210° C., the melt temperature is 235° C., and the pellets after extrusion are dried at 70° C. for 2 hours to obtain the reinforced masterbatch;

[0082] The preparation method of the HDPE double-wall corrugated pipe comprises the following steps:

[0083] Step 1: Accurately weigh the raw materials required for preparing the inner wall and outer wall of the HDPE double-wall corrugated pipe according to the formula, then place the weighed raw materials in a mixing device, and after mechanical mixing and stirring, transfer the resulting mixed material to the feeding funnel of the single screw extruder;

[0084] Step 2: melt-extrude the mixture obtained in step 1 through an extruder, and the melt passes through a die to obtain a corrugated pipe blank, and the corrugated pipe blank is sent to a corrugated pipe forming machine for forming to obtain a rough corrugated pipe.

[0085] Step 3: Send the crude HDPE double-wall corrugated pipe product obtained in step 2 to a high-pressure atomizing nozzle for spraying and cooling, and cut it after drying to obtain a HDPE double-wall corrugated pipe.

[0086] Example 1

[0087] This embodiment provides a reinforcing masterbatch composed of the following materials in parts by weight: 60 parts of UHMWPE, 35 parts of modified glass fiber, 8 parts of polyethylene wax, and 0.3 parts of antioxidant 1010.

[0088] The UHMWPE is UHMWPE-3, and its molecular weight is 1.1 million.

[0089] A HDPE double-wall corrugated pipe, consisting of an annular outer wall and a smooth inner wall. The annular outer wall and the smooth inner wall are extruded and fed by two single-screw extruders respectively. The material used for the smooth inner wall is composed of the following materials by weight: 100 parts of HDPE, 75 parts of reinforcing masterbatch, 4 parts of color masterbatch, and 3 parts of defoaming agent. The material used for the annular outer wall is composed of the following materials by weight: 100 parts of HDPE, 120 parts of reinforcing masterbatch, 4 parts of black masterbatch, and 3 parts of defoaming agent.

[0090] The HDPE in the inner wall and the outer wall has a melt flow rate of 0.3 g / 10 min (190° C. / 5 kg).

[0091] Example 2

[0092] The HDPE double-wall corrugated pipe provided in this embodiment is different from that in Embodiment 1 only in that the modified glass fiber component of the reinforcing masterbatch in this embodiment is replaced with modified basalt fiber, and the rest is the same as that in Embodiment 1.

[0093] Example 3

[0094] The HDPE double-wall corrugated pipe provided in this embodiment is different from that in Embodiment 1 only in that the UHMWPE in this embodiment is UHMWPE-1, and its molecular weight is 500,000, and the rest is the same as that in Embodiment 1.

[0095] Example 4

[0096] The HDPE double-wall corrugated pipe provided in this embodiment is different from that in Embodiment 1 only in that the UHMWPE in this embodiment is UHMWPE-2, and its molecular weight is 1.5 million, and the rest is the same as that in Embodiment 1.

[0097] Example 5

[0098] The HDPE double-wall corrugated pipe provided in this embodiment is different from that in Embodiment 1 only in that the amount of reinforcing masterbatch added to the outer wall of the HDPE double-wall corrugated pipe in this embodiment is 150 parts, and the rest is the same as that in Embodiment 1.

[0099] Example 6

[0100] The HDPE double-wall corrugated pipe provided in this embodiment is different from that in Embodiment 1 only in that the amount of reinforcing masterbatch added to the outer wall of the HDPE double-wall corrugated pipe in this embodiment is 100 parts, and the rest is the same as that in Embodiment 1.

[0101] Example 7

[0102] The HDPE double-wall corrugated pipe provided in this embodiment is different from that in Embodiment 1 only in that the amount of reinforcing masterbatch added to the inner wall of the HDPE double-wall corrugated pipe in this embodiment is 50 parts, and the rest is the same as that in Embodiment 1.

[0103] Example 8

[0104] The HDPE double-wall corrugated pipe provided in this embodiment is different from that in Embodiment 1 only in that the amount of reinforcing masterbatch added to the inner wall of the HDPE double-wall corrugated pipe in this embodiment is 100 parts, and the rest is the same as that in Embodiment 1.

[0105] Comparative Example 1

[0106] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that no modified glass fiber is added to the reinforcing masterbatch of the HDPE double-wall corrugated pipe.

[0107] Comparative Example 2

[0108] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that the glass fiber added to the reinforcing masterbatch of the HDPE double-wall corrugated pipe is not modified.

[0109] Comparative Example 3

[0110] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that UHMWPE is not added to the reinforcing masterbatch of the HDPE double-wall corrugated pipe.

[0111] Comparative Example 4

[0112] The only difference between the HDPE double-wall corrugated pipe provided in this comparative example and Example 1 is that the amount of reinforcing masterbatch added to the outer wall of the HDPE double-wall corrugated pipe is 200 parts.

[0113] Comparative Example 5

[0114] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that the UHMWPE in the reinforcing masterbatch of the HDPE double-wall corrugated pipe is UHMWPE-4, and its molecular weight is 2 million.

[0115] Comparative Example 6

[0116] The HDPE double-wall corrugated pipe provided in this comparative example is different from that in Example 1 only in that the melt temperature is 245° C. when preparing the reinforced masterbatch.

[0117] Comparative Example 7

[0118] The HDPE double-wall corrugated pipe provided in this comparative example is different from that in Example 1 only in that the melt temperature is 210° C. when preparing the reinforced masterbatch.

[0119] Comparative Example 8

[0120] The only difference between the HDPE double-wall corrugated pipe provided in this comparative example and Example 1 is that there is no step of preparing the reinforcing masterbatch in the method for preparing the outer wall of the HDPE double-wall corrugated pipe, and HDPE, UHMWPE, modified glass fiber, polyethylene wax, antioxidant 1010, black masterbatch, and defoaming agent are directly weighed according to the formula and extruded into shape.

[0121] Comparative Example 9

[0122] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that the mass fraction of UHMWPE in the reinforcing masterbatch of the HDPE double-wall corrugated pipe is 85 parts.

[0123] Comparative Example 10

[0124] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that the mass fraction of UHMWPE in the reinforcing masterbatch of the HDPE double-wall corrugated pipe is 35 parts.

[0125] Comparative Example 11

[0126] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that the mass fraction of the modified glass fiber in the reinforcing masterbatch of the HDPE double-wall corrugated pipe is 50 parts.

[0127] Comparative Example 12

[0128] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that the mass fraction of the modified glass fiber in the reinforcing masterbatch of the HDPE double-wall corrugated pipe is 20 parts.

[0129] Comparative Example 13

[0130] The HDPE double-wall corrugated pipe provided in this comparative example is different from that in Example 1 only in that the twin-screw extruder used for granulating the reinforced masterbatch has a length-to-diameter ratio of 42:1.

[0131] Comparative Example 14

[0132] The HDPE double-wall corrugated pipe provided in this comparative example is different from Example 1 only in that the amount of reinforcing masterbatch added to the inner wall of the HDPE double-wall corrugated pipe is 150 parts.

[0133] The HDPE double-wall corrugated pipe (DN / ID300) prepared in the above embodiments and comparative examples was tested for ring stiffness according to the method in GB / T9647-2015; the impact performance was tested according to the method in GB / T 14152-2001; the creep ratio was tested according to the method in GB / T18042-2000; the test results are shown in Table 1.

[0134] Table 1

[0135]

[0136] It can be seen from Examples 1-8 that by replacing the inorganic columnar fibers described in the present invention or controlling the molecular weight of ultra-high molecular weight polyethylene within the range of 500,000-1.5 million, adding 50-100 parts of inner wall reinforcement masterbatch, and adding 100-150 parts of outer wall reinforcement masterbatch, the performance of the corrugated pipe can meet the requirements.

[0137] From the comparison between Example 1 and Comparative Examples 1-2, it can be seen that if UHMWPE is not well combined with the inorganic fiber, the creep ratio of the double-wall corrugated pipe will not meet the index requirements, and the ring stiffness will also decrease to a certain extent.

[0138] It can be seen from Comparative Example 3 that if only glass fiber is introduced into the double-wall corrugated pipe without introducing UHMWPE, the ring stiffness and drop weight impact performance of the pipe will be difficult to meet the index requirements.

[0139] It can be seen from Comparative Example 4 that when the amount of outer wall reinforcement masterbatch added is too much, the ring stiffness of the double-wall corrugated pipe can be improved, but the drop hammer impact performance declines, and the processing difficulty of the double-wall corrugated pipe preparation increases.

[0140] It can be seen from Comparative Example 5 that when UHMWPE with too high a molecular weight is used, the difficulty of extrusion plasticization of the reinforcing masterbatch is greatly increased, the bonding effect of UHMWPE and glass fiber becomes worse, and although the ring stiffness of the pipe meets the requirements, the drop weight impact performance and creep ratio are both poor.

[0141] It can be seen from Comparative Example 6 that when the melt temperature during the granulation of the reinforced masterbatch reaches 245°C, UHMWPE undergoes a certain degree of molecular chain degradation, the ring stiffness decreases, and the drop hammer impact performance is also poor.

[0142] It can be seen from Comparative Example 7 that when the melt temperature during the granulation of the reinforcing masterbatch is only 210°C, the UHMWPE molecular chains are not fully disentangled due to insufficient plasticization, and the ring stiffness and drop hammer impact performance are poor.

[0143] It can be seen from Comparative Example 8 that when the raw material formula of the reinforcing masterbatch is directly added to the pipe formula without going through the step of granulating the reinforcing masterbatch, the drop weight impact performance and creep ratio are insufficient because UHMWPE fails to effectively combine with the columnar fibers.

[0144] From Comparative Example 9, it can be seen that when the weight proportion of UHMWPE in the reinforcing masterbatch is 80 parts, since the reinforcing masterbatch is mainly composed of UHMWPE, most of the UHMWPE cannot reduce the creep shrinkage of the molecular chain by winding with the columnar fibers, so the creep ratio of the prepared double-corrugated tube is relatively large.

[0145] It can be seen from Comparative Example 10 that when the weight proportion of UHMWPE in the reinforcing masterbatch is 35 parts, due to the low content of UHMWPE in the reinforcing masterbatch, the melt plasticization is poor, and poor drop hammer impact performance is exhibited.

[0146] It can be seen from Comparative Example 11 that when the modified glass fiber in the reinforcing masterbatch accounts for 50 parts by weight, the drop hammer impact performance of the prepared pipe is poor due to the excessively high content of inorganic materials in the reinforcing masterbatch.

[0147] From Comparative Example 12, it can be seen that when the weight proportion of modified glass fiber in the reinforcing masterbatch is 20 parts, since the content of inorganic material in the reinforcing masterbatch is too small, the molecular chain of UHMWPE cannot be entangled and constrained, resulting in a large creep ratio.

[0148] From Comparative Example 13, it can be seen that when the aspect ratio of the twin-screw extruder used for the extrusion of the reinforcing masterbatch is 42:1, the UHMWPE molecular chain is not fully untangled, showing insufficient ring stiffness. At the same time, UHMWPE and glass fiber are not effectively entangled, showing a large creep ratio.

[0149] It can be seen from Comparative Example 14 that when the amount of inner wall reinforcement masterbatch added is too much, the ring stiffness of the double-wall corrugated pipe can be improved, but the drop hammer impact performance declines. At the same time, the processing difficulty of the double-wall corrugated pipe preparation increases, and the smoothness of the inner wall decreases.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A HDPE double-wall corrugated pipe reinforcement masterbatch, characterized in that: The invention comprises the following components in parts by weight: 50-70 parts of UHMWPE, 30-40 parts of modified inorganic fiber, and 5-10 parts of lubricant; The molecular weight of the UHMWPE is 500,000-1.5 million; the length-to-diameter ratio of the twin-screw extruder used in the preparation of the reinforced masterbatch is ≥48:1, and the melt temperature is 220-240°C.

2. The HDPE double-wall corrugated pipe reinforcement masterbatch according to claim 1, characterized in that: The modified inorganic fiber is at least one of glass fiber, basalt fiber, silicon carbide fiber and alumina fiber.

3. The HDPE double-wall corrugated pipe reinforcement masterbatch according to claim 1, characterized in that: The modified inorganic fiber is surface silane-grafted modified inorganic fiber.

4. The HDPE double-wall corrugated pipe reinforcement masterbatch according to claim 1, characterized in that: The reinforced masterbatch also includes 0.2-0.4 parts of antioxidant.

5. Use of the reinforcing masterbatch according to any one of claims 1 to 4 in the preparation of HDPE double-wall corrugated pipes.

6. A HDPE double-wall corrugated pipe composition, characterized in that: The composition is an outer wall composition or an inner wall composition. The outer wall composition comprises the following components in parts by weight: 100 parts of HDPE, 100-150 parts of the reinforcing masterbatch as described in any one of claims 1 to 4, and 3-5 parts of the masterbatch; the inner wall composition comprises the following components in parts by weight: 100 parts of HDPE, 50-100 parts of the reinforcing masterbatch as described in any one of claims 1 to 4, and 3-5 parts of the masterbatch.

7. The HDPE double-wall corrugated pipe composition according to claim 6, characterized in that: The melt flow rate of the HDPE in the outer wall composition or the inner wall composition at 190° C. and 5 kg is less than 1.5 g / 10 min.

8. A HDPE double-wall corrugated pipe, the pipe wall of which includes an inner wall and an outer wall, characterized in that: The outer wall comprises the outer wall composition as claimed in claim 6, and the inner wall comprises the inner wall composition as claimed in claim 6.

9. A method for preparing a HDPE double-wall corrugated pipe as claimed in claim 8, comprising the following steps: Step 1, mixing the raw materials and transferring them into a single screw extruder to obtain a mixed material; Step 2: Melt and extrude the mixed material to obtain a corrugated pipe blank, and shape it to obtain a rough corrugated pipe; Step 3: Cool down and cut the crude corrugated pipe to obtain a HDPE double-wall corrugated pipe.

10. Use of the HDPE double-wall corrugated pipe as claimed in claim 8 in drainage and sewage treatment.

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