Flame-retardant and noise-reducing polyethylene drainage pipe

Abstract

The invention discloses a flame-retardant noise-reducing polyethylene drainage pipe, which belongs to the technical field of drainage pipes, and comprises a PE flame-retardant outer layer, a PE flame-retardant noise-reducing middle layer and a PE flame-retardant inner layer, the PE flame-retardant noise-reducing middle layer is prepared from the following raw materials in parts by weight: 30-40 parts of high-density polyethylene, 30-40 parts of composite particles and 6-8 parts of flame-retardant master batch; according to the invention, the composite particles are added into the PE flame-retardant noise-reducing middle layer, the composite particles are barium sulfate coated with the polymer, and the polymer is polysiloxane, so that the sound absorption or sound insulation performance of the PE flame-retardant noise-reducing middle layer is improved, and the better the dispersion effect of the composite particles and the matrix is, the better the sound insulation performance is improved. Polysiloxane is introduced into the composite particles added into the PE flame-retardant noise-reducing middle layer of the polyethylene drainage pipe, and can form a good synergistic flame-retardant effect with a small amount of added flame retardant, so that the flame-retardant grade of the drainage pipe reaches V-0 grade.

Description

Technical Field

[0001] The invention belongs to the technical field of drainage pipes, and in particular relates to a flame-retardant and noise-reducing polyethylene drainage pipe. Background Art

[0002] Existing building drainage pipes are mostly plastic drainage pipes, such as PVC (polyvinyl chloride) pipes, PE (polyethylene) pipes and PP (polypropylene) pipes, and PVC pipes are the main ones. However, compared with PVC and PP pipes, PE pipes have better performance in actual application, such as corrosion resistance, flexibility and low temperature resistance. At the same time, they also have the advantages of long service life, low production energy consumption, small water flow resistance, easy installation and disassembly. They are expected to gradually replace PVC pipes and become a more widely used pipe material. At present, HDPE pipes have been widely used in siphon drainage or gravity drainage.

[0003] However, the existing PE pipes have the following problems when used as water supply and drainage pipes, which limit their promotion and application: (1) PE pipes have poor flame retardancy; since PE material is a flammable polymer with an oxygen index of less than 18%, pipes made of PE material generally have the defect of poor flame retardancy. Therefore, in order to improve the safety of PE pipes when used as drainage pipes in high-rise buildings, it is necessary to improve the flame retardancy of PE drainage pipes. (2) High noise; the noise of building drainage pipes is a combination of aerodynamic sound transmission and solid sound transmission, that is, the building drainage pipes are full of air. When draining, there is both sound wave transmission with air as the medium and noise caused by pipe vibration caused by the impact of water and solid impurities on the pipe wall when flowing. Especially for high-rise building water supply and drainage pipes, the noise generated during the water supply and drainage process is one of the main noise sources in the interior of high-rise buildings. Therefore, it is necessary to improve the sound insulation performance of PE pipes when used as building water supply and drainage.

[0004] If the noise in plastic drainage pipes is to be reduced, the material or structure of the plastic pipe should be able to absorb the noise generated by sound waves and pipe wall vibration. In order to reduce the water supply and drainage noise of plastic pipes, a multi-layer pipe structure is currently used, which contains an intermediate sound-absorbing layer. There are currently two common technologies for the intermediate sound-absorbing layer. One is to use inorganic fillers such as light calcium carbonate and barium sulfate to fill the intermediate layer, so that the pipe has certain sound insulation and noise reduction properties. The other is to use foaming technology to form a microporous structure in the intermediate layer in an attempt to make the pipe have certain sound insulation and noise reduction capabilities.

[0005] If the flame retardancy of pipes is to be improved, the following technical problems generally exist: (1) The existing pipes are of a single-layer structure, which can achieve flame retardancy, but cannot achieve sound insulation and noise reduction capabilities; (2) If the existing pipes adopt a multi-layer structure, the inner and outer layers achieve flame retardancy, and the middle layer only has noise reduction but no flame retardancy. According to the standard "GB / T2408-2021 Horizontal and vertical methods for the determination of combustion performance of plastics", it is necessary to cut into strips for testing. The middle layer has no flame retardancy, so it is impossible to achieve a V0 flame retardancy grade. In addition, it is difficult for existing all-PE pipes, whether single-layer or three-layer, to reach the V0 level. For example, the patent application with publication number CN113845712A records a flame retardant A flame-retardant and sound-proof high-rise PE drainage pipe and a preparation method thereof, the drainage pipe comprises a three-layer structure of a PE flame-retardant inner layer, a PE foamed middle layer and an outer protective layer, wherein flame retardants are added to the raw materials for preparing the PE flame-retardant inner layer and the outer protective layer, and the flame retardant grade of the drainage pipe is comprehensively improved by improving the flame retardant properties of the inner and outer layers, so that the flame retardant grade of the drainage pipe reaches V-0 level; in addition, the PE foamed middle layer is formed by foaming mainly with foamed-grade LDPE, which effectively improves the noise reduction performance of the drainage pipe and can reduce the drainage noise by 32 to 34dB, but the outer layer needs to be made of PVC material. The use of PVC material for the outer layer greatly increases the processing difficulty and there are compatibility issues between PVC and PE. Summary of the invention

[0006] The purpose of the present invention is to provide a flame retardant and noise reducing polyethylene drainage pipe to solve the problem of poor sound insulation performance of the polyethylene drainage pipe.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A flame retardant and noise-reducing polyethylene drainage pipe comprises a PE flame retardant outer layer, a PE flame retardant and noise-reducing middle layer and a PE flame retardant inner layer; the PE flame retardant and noise-reducing middle layer is prepared from the following raw materials in parts by weight: 30-40 parts of high-density polyethylene, 30-40 parts of composite particles, and 6-8 parts of flame retardant masterbatch; the composite particles are polymer-coated barium sulfate, and the polymer is polysiloxane.

[0009] In some possible implementations, the composite particles are prepared by the following steps:

[0010] Add barium sulfate to an ethanol aqueous solution, add ammonia water to adjust the pH value of the system to 9-10, add ethyl orthosilicate and other organic silicon compounds, stir and react at a temperature of 40-45°C for 2.5-3h, wash with anhydrous ethanol, and dry at 80°C to obtain composite particles.

[0011] In some possible implementations, the other organic silicon compound is at least one of dimethyldiethoxysilane, methyltriethoxysilane, triethoxypentylsilane, n-octyltriethoxysilane and n-hexyltriethoxysilane.

[0012] In some possible implementations, the ethanol aqueous solution is a mixture of ethanol and water in a volume ratio of 2-3:1; the usage ratio of barium sulfate and ethanol aqueous solution is 1 g: 4-5 mL;

[0013] The mass ratio of barium sulfate, ethyl orthosilicate and other organic silicon compounds is 5-6:1-2:1-2.

[0014] The barium sulfate powder is 1200-1300 mesh.

[0015] In some possible implementations, the PE flame retardant outer layer and the PE flame retardant inner layer are prepared from the following raw materials in parts by weight: 35-60 parts of high-density polyethylene and 40-65 parts of flame retardant masterbatch.

[0016] In some possible implementations, the flame retardant masterbatch is prepared by melt, shear blending, extrusion granulation and granulation of 30-50 parts of high-density polyethylene, 50-70 parts of compound flame retardant powder, 0.1-0.8 parts of antioxidant, 0.5-2 parts of coupling agent and 0.2-1 parts of lubricant by weight.

[0017] In some possible implementations, the composite flame retardant powder includes piperazine pyrophosphate, melamine polyphosphate and hypophosphite, wherein the hypophosphite is one of diethyl aluminum hypophosphite, diethyl cerium hypophosphite, diethyl calcium hypophosphite, dipropyl aluminum hypophosphite and methyl ethyl aluminum hypophosphite;

[0018] In some possible implementations, the mass ratio of piperazine pyrophosphate, melamine polyphosphate and hypophosphite is 5-7:3-5:1.

[0019] In some possible implementations, the antioxidant is one of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 626;

[0020] The coupling agent is one of KH550, KH560 and KH570 coupling agents;

[0021] The lubricant is at least one of erucamide, ethylene bis stearamide, pentaerythritol stearate and polyethylene wax.

[0022] In some possible implementations, the thickness ratio of the PE flame retardant outer layer, the PE flame retardant noise reduction middle layer and the PE flame retardant inner layer is (0.8-2):(6-8):(0.8-2).

[0023] Beneficial effects of the present invention:

[0024] The present invention provides a flame retardant and noise-reducing polyethylene drain pipe, comprising a PE flame retardant outer layer, a PE flame retardant and noise-reducing middle layer, and a PE flame retardant inner layer. In the present invention, composite particles are added to the PE flame retardant and noise-reducing middle layer, and the composite particles are barium sulfate coated with a polymer, and the polymer is polysiloxane, thereby increasing the sound absorption or sound insulation performance of the PE flame retardant and noise-reducing middle layer. The better the dispersion effect of the composite particles and the matrix (PE), the more conducive to the improvement of the sound insulation performance. If it is difficult to achieve the flame retardant requirements of the polyethylene drain pipe by relying solely on the PE flame retardant outer layer and the PE flame retardant inner layer, the composite particles added to the PE flame retardant and noise-reducing middle layer of the polyethylene drain pipe in the present invention introduce polysiloxane, which can form a good synergistic flame retardant effect with a small amount of flame retardant added, so that the flame retardant grade of the drain pipe reaches the V-0 level. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Obviously, the following descriptions are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in the field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0027] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.

[0028] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0029] Materials with high density or high surface density have higher sound absorption or sound insulation capabilities. In the present invention, composite particles are added to the PE flame retardant and noise reduction middle layer. The composite particles are barium sulfate coated with a polymer, and the polymer is polysiloxane, thereby increasing the sound absorption or sound insulation performance of the PE flame retardant and noise reduction middle layer.

[0030] The following is a detailed description of a flame retardant and noise reducing polyethylene drainage pipe according to an embodiment of the present application.

[0031] The embodiment of the present application proposes a flame-retardant and noise-reducing polyethylene drain pipe, comprising a PE flame-retardant outer layer, a PE flame-retardant and noise-reducing middle layer and a PE flame-retardant inner layer; the PE flame-retardant and noise-reducing middle layer is prepared from the following raw materials in parts by weight: 30-40 parts of high-density polyethylene, 30-40 parts of composite particles, and 6-8 parts of flame-retardant masterbatch; the composite particles are polymer-coated barium sulfate, and the polymer is polysiloxane. The better the dispersion effect of the polysiloxane (a porous skeleton formed with tetraethyl orthosilicate and other organic silicon compounds as raw materials) on the surface of the composite particles and the matrix (PE), the more conducive it is to the improvement of the sound insulation performance. The cavity corresponding to the porous structure can better capture the medium sound waves, dissipate the sound energy through the cavity resonance, and further improve the noise reduction effect.

[0032] In some embodiments, the composite microparticles are prepared by the following steps:

[0033] Add barium sulfate to an ethanol aqueous solution, add ammonia water to adjust the pH value of the system to 9-10, add tetraethyl orthosilicate and other organic silicon compounds, stir and react at a temperature of 40-45°C for 2.5-3h, wash with anhydrous ethanol after the reaction, and dry at 80°C to obtain composite particles. The composite particles are obtained by hydrolyzing and polycondensing tetraethyl orthosilicate and other organic silicon compounds to cover the surface of barium sulfate with polysiloxane having a three-dimensional porous skeleton.

[0034] In some embodiments, the other organosilicon compound is at least one of dimethyldiethoxysilane, methyltriethoxysilane, triethoxypentylsilane, n-octyltriethoxysilane and n-hexyltriethoxysilane. Long-chain alkyl groups are introduced into other organosilicon compounds to increase their similarity with polyethylene and improve compatibility.

[0035] In some embodiments, the ethanol aqueous solution is a mixture of ethanol and water in a volume ratio of 2-3:1. The dosage ratio of barium sulfate to ethanol aqueous solution is 1g:4-5mL;

[0036] The mass ratio of barium sulfate, ethyl orthosilicate and other organic silicon compounds is 5-6:1-2:1-2.

[0037] The barium sulfate powder is 1200-1300 mesh.

[0038] In some embodiments, the PE flame retardant outer layer and the PE flame retardant inner layer are prepared from the following raw materials in parts by weight: 35-60 parts of high-density polyethylene and 40-65 parts of flame retardant masterbatch.

[0039] In some embodiments, the flame retardant masterbatch is prepared by melt, shear blending, extrusion granulation and granulation of 30-50 parts of high-density polyethylene, 50-70 parts of compound flame retardant powder, 0.1-0.8 parts of antioxidant, 0.5-2 parts of coupling agent and 0.2-1 parts of lubricant by weight.

[0040] In some embodiments, the composite flame retardant powder includes piperazine pyrophosphate, melamine polyphosphate and hypophosphite, wherein the hypophosphite is one of diethyl aluminum hypophosphite, diethyl cerium hypophosphite, diethyl calcium hypophosphite, dipropyl aluminum hypophosphite and methyl ethyl aluminum hypophosphite. The flame retardant performance is improved by combining different types of flame retardants.

[0041] In some embodiments, the mass ratio of piperazine pyrophosphate, melamine polyphosphate and hypophosphite is 5-7:3-5:1.

[0042] In some embodiments, the antioxidant is one of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 626;

[0043] The coupling agent is one of KH550, KH560 and KH570 coupling agents;

[0044] The lubricant is at least one of erucamide, ethylene bis stearamide, pentaerythritol stearate and polyethylene wax.

[0045] In some embodiments, the thickness ratio of the PE flame retardant outer layer, the PE flame retardant noise reduction middle layer and the PE flame retardant inner layer is (0.8-2): (6-8): (0.8-2). This ratio is based on cost considerations and also on maximum noise reduction performance considerations.

[0046] There is no special requirement for the preparation method of the polyethylene drainage pipe disclosed in the present invention. The raw materials corresponding to the three layers of PE flame retardant outer layer, PE flame retardant noise reduction middle layer and PE flame retardant inner layer can be extruded and melted into a melt through three screw extruders. The melts corresponding to the three layers of PE flame retardant outer layer, PE flame retardant noise reduction middle layer and PE flame retardant inner layer flow into branch channels of set width and thickness from a head feed end with three flow channels respectively. After the three layers of melt are compound-formed in the head model, they are cooled, pulled and cut.

[0047] The prepared sample to be tested has an inner diameter of 75 mm and a thickness of 3.7 mm±0.1 mm.

[0048] The following describes the invention in conjunction with specific embodiments.

[0049] Example 1

[0050] The embodiment of the present application proposes a flame retardant and noise-reducing polyethylene drainage pipe, including a PE flame retardant outer layer, a PE flame retardant and noise-reducing middle layer and a PE flame retardant inner layer; the thickness ratio of the PE flame retardant outer layer, the PE flame retardant and noise-reducing middle layer and the PE flame retardant inner layer is 0.8:6:0.8.

[0051] The PE flame retardant noise reduction middle layer is prepared from the following raw materials in parts by weight: 30 parts of high-density polyethylene, 30 parts of composite particles, and 6 parts of flame retardant masterbatch; the composite particles are polymer-coated barium sulfate, and the polymer is polysiloxane. The composite particles are prepared by the following steps:

[0052] Add barium sulfate to ethanol aqueous solution (ethanol and water are mixed in a volume ratio of 2:1), add ammonia water to adjust the pH value of the system to 9, add ethyl orthosilicate and n-hexyltriethoxysilane (diluted with n-hexane), stir and react at 40°C for 2.5h, wash with anhydrous ethanol after the reaction, and dry at 80°C to obtain composite particles; the dosage ratio of barium sulfate and ethanol aqueous solution is 1g:4mL; the dosage mass ratio of barium sulfate, ethyl orthosilicate and n-hexyltriethoxysilane is 5:1:1. The barium sulfate powder is 1200 mesh.

[0053] The PE flame-retardant outer layer and the PE flame-retardant inner layer are prepared from the following raw materials in parts by weight: 35 parts of high-density polyethylene and 40 parts of flame-retardant masterbatch.

[0054] The flame retardant masterbatch is prepared by melting, shearing, blending, extruding and granulating 30 parts of high-density polyethylene, 50 parts of compound flame retardant powder, 0.1 parts of antioxidant 1010, 0.5 parts of KH570 coupling agent and 0.2 parts of polyethylene wax.

[0055] The compound flame retardant powder comprises piperazine pyrophosphate, melamine polyphosphate and diethyl aluminum hypophosphite, and the mass ratio of piperazine pyrophosphate, melamine polyphosphate and diethyl aluminum hypophosphite is 5:3:1.

[0056] The high-density polyethylene used is PE100 grade, with a melt index of 0.5g / 10min, and the test conditions are 190°C and 5kg.

[0057] Example 2

[0058] The embodiment of the present application proposes a flame retardant and noise-reducing polyethylene drainage pipe, including a PE flame retardant outer layer, a PE flame retardant and noise-reducing middle layer and a PE flame retardant inner layer; the thickness ratio of the PE flame retardant outer layer, the PE flame retardant and noise-reducing middle layer and the PE flame retardant inner layer is 0.8:6:0.8.

[0059] The PE flame retardant noise reduction middle layer is prepared from the following raw materials in parts by weight: 30 parts of high-density polyethylene, 30 parts of composite particles, and 6 parts of flame retardant masterbatch; the composite particles are polymer-coated barium sulfate, and the polymer is polysiloxane. The composite particles are prepared by the following steps:

[0060] Add barium sulfate to ethanol aqueous solution (ethanol and water are mixed in a volume ratio of 3:1), add ammonia water to adjust the pH value of the system to 10, add ethyl orthosilicate and n-hexyltriethoxysilane (diluted with n-hexane), stir and react at 45°C for 3h, wash with anhydrous ethanol after the reaction, and dry at 80°C to obtain composite particles; the dosage ratio of barium sulfate and ethanol aqueous solution is 1g:5mL; the dosage mass ratio of barium sulfate, ethyl orthosilicate and n-hexyltriethoxysilane is 3:1:1. The barium sulfate powder is 1200 mesh.

[0061] The PE flame-retardant outer layer and the PE flame-retardant inner layer are prepared from the following raw materials in parts by weight: 60 parts of high-density polyethylene and 65 parts of flame-retardant masterbatch.

[0062] The flame retardant masterbatch is prepared by melting, shearing, blending, extruding and granulating 50 parts of high-density polyethylene, 70 parts of compound flame retardant powder, 10100.8 parts of antioxidant, 2 parts of KH570 coupling agent and 1 part of polyethylene wax.

[0063] The compound flame retardant powder comprises piperazine pyrophosphate, melamine polyphosphate and diethylaluminum hypophosphite, and the mass ratio of piperazine pyrophosphate, melamine polyphosphate and diethylaluminum hypophosphite is 7:5:1.

[0064] The high-density polyethylene used is PE100 grade, with a melt index of 0.5g / 10min, and the test conditions are 190°C and 5kg.

[0065] Example 3

[0066] The difference between this embodiment and embodiment 1 is that the raw material ratio of the PE flame retardant and noise reduction middle layer is different. Specifically, in this embodiment, it is prepared from the following raw materials in parts by weight: 40 parts of high-density polyethylene, 30 parts of composite particles, and 6 parts of flame retardant masterbatch; the remaining raw materials and preparation process remain the same as in embodiment 1.

[0067] Example 4

[0068] The difference between this embodiment and embodiment 1 is that the raw material ratio of the PE flame retardant and noise reduction middle layer is different. Specifically, in this embodiment, it is prepared from the following raw materials in parts by weight: 30 parts of high-density polyethylene, 40 parts of composite particles, and 8 parts of flame retardant masterbatch; the remaining raw materials and preparation process remain the same as in embodiment 1.

[0069] Example 5

[0070] The difference between this embodiment and embodiment 1 is that the preparation process of the composite particles is different. The specific composite particles are prepared by the following steps:

[0071] Add barium sulfate to an ethanol aqueous solution (ethanol and water are mixed in a volume ratio of 2:1), add ammonia water to adjust the pH value of the system to 10, add tetraethyl orthosilicate, dimethyldiethoxysilane and n-octyltriethoxysilane (diluted with n-hexane), stir and react at a temperature of 40°C for 2.5 hours, wash with anhydrous ethanol after the reaction, and dry at 80°C to obtain composite particles. The amount ratio of barium sulfate to ethanol aqueous solution is 1g:4mL; the mass ratio of barium sulfate, tetraethyl orthosilicate, dimethyldiethoxysilane and n-octyltriethoxysilane is 5:1:1:1.

[0072] Example 6

[0073] The difference between this embodiment and embodiment 1 is that the preparation process of the composite particles is different. The specific composite particles are prepared by the following steps:

[0074] Add barium sulfate to an ethanol aqueous solution (ethanol and water are mixed in a volume ratio of 2:1), add ammonia water to adjust the pH value of the system to 10, add orthosilicic acid, ethyl methyl triethoxysilane and triethoxypentylsilane (diluted with n-hexane), stir and react at a temperature of 40°C for 2.5 hours, wash with anhydrous ethanol after the reaction, and dry at 80°C to obtain composite particles. The amount ratio of barium sulfate to ethanol aqueous solution is 1g:4mL; the mass ratio of barium sulfate, ethyl orthosilicate, ethyl methyl triethoxysilane and triethoxypentylsilane is 5:1:1:1.

[0075] Example 7

[0076] The difference between this embodiment and embodiment 1 is that the preparation process of the composite particles is different. The specific composite particles are prepared by the following steps:

[0077] Add barium sulfate to an ethanol aqueous solution (ethanol and water are mixed in a volume ratio of 2:1), add ammonia water to adjust the pH value of the system to 10, add ethyl orthosilicate and n-hexyltriethoxysilane, stir and react at a temperature of 40°C for 2.5 hours, wash with anhydrous ethanol after the reaction, and dry at 80°C to obtain composite particles. The dosage ratio of barium sulfate and ethanol aqueous solution is 1g:4mL; the dosage mass ratio of barium sulfate, ethyl orthosilicate and n-hexyltriethoxysilane is 5:1:1.

[0078] Example 8

[0079] The difference between the embodiment and embodiment 1 is that the preparation process of the composite particles is different. The specific composite particles are prepared by the following steps:

[0080] Add barium sulfate to an ethanol aqueous solution (ethanol and water are mixed in a volume ratio of 2:1), add ammonia water to adjust the pH value of the system to 10, add ethyl orthosilicate and triethoxypentylsilane (diluted with n-hexane), stir and react at a temperature of 40°C for 2.5 hours, wash with anhydrous ethanol after the reaction, and dry at 80°C to obtain composite particles. The dosage ratio of barium sulfate and ethanol aqueous solution is 1g:4mL; the dosage mass ratio of barium sulfate, ethyl orthosilicate and triethoxypentylsilane is 5:1:1.

[0081] Comparative Example 1

[0082] Compared with Example 1, this comparative example differs in that untreated barium sulfate is used to replace the composite particles in Example 1, and the other raw materials and preparation process remain the same as those in Example 1.

[0083] Comparative Example 2

[0084] The difference between this comparative example and Example 1 is that barium sulfate treated with a silane coupling agent is used to replace the composite particles in Example 1; the preparation steps of barium sulfate treated with a silane coupling agent are as follows:

[0085] The silane coupling agent KH-570 and anhydrous ethanol are prepared into a mixed solution at a ratio of 1:100, and then barium sulfate is added into the mixed solution and stirred sufficiently so that KH-570 can fully adsorb the surface of the barium sulfate. Subsequently, the mixed solution is placed in a blast and dried at 100°C for 4 hours to obtain barium sulfate treated with a silane coupling agent.

[0086] The rest of the raw materials and preparation process remain the same as in Example 1.

[0087] Comparative Example 3

[0088] The difference between this comparative example and Example 1 is that the raw material ratio of the PE flame retardant and noise reduction middle layer is different. Specifically, in this example, it is prepared from the following raw materials in parts by weight: 40 parts of high-density polyethylene, 20 parts of composite particles, and 6 parts of flame retardant masterbatch; the remaining raw materials and preparation process remain the same as in Example 1.

[0089] Comparative Example 4

[0090] The difference between this comparative example and Example 1 is that the raw material ratio of the PE flame retardant and noise reduction middle layer is different. Specifically, in this example, it is prepared from the following raw materials in parts by weight: 50 parts of high-density polyethylene, 10 parts of composite particles, and 6 parts of flame retardant masterbatch; the remaining raw materials and preparation process remain the same as in Example 1.

[0091] Performance tests were performed on Examples 1 to 8 and Comparative Examples 1 to 4;

[0092] The mechanical properties refer to GB-T 8804.3-2003 Thermoplastic Pipe Tensile Properties Determination Part 3; the noise reduction performance refers to CJ-T312-2009: Building Drainage Pipe System Noise Test Method; the flame retardant performance refers to the UL94 flame retardant grade measurement method for testing; the results are shown in Table 1:

[0093] Table 1

[0094]

[0095]

[0096] It can be seen from Table 1 that the drainage pipe prepared by the present invention has strong tensile strength, excellent noise reduction performance, and flame retardant performance that can reach V-0 level.

[0097] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0098] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A flame retardant and noise reducing polyethylene drainage pipe, characterized in that: It includes a PE flame-retardant outer layer, a PE flame-retardant noise-reducing middle layer and a PE flame-retardant inner layer; the PE flame-retardant noise-reducing middle layer is prepared from the following raw materials in parts by weight: 30-40 parts of high-density polyethylene, 30-40 parts of composite particles, and 6-8 parts of flame-retardant masterbatch; the composite particles are polymer-coated barium sulfate, and the polymer is polysiloxane.

2. The flame retardant and noise reducing polyethylene drainage pipe according to claim 1, characterized in that: The composite particles are prepared by the following steps: Add barium sulfate to an ethanol aqueous solution, add ammonia water to adjust the pH value of the system to 9-10, add ethyl orthosilicate and other organic silicon compounds, stir and react at a temperature of 40-45°C for 2.5-3h, wash with anhydrous ethanol, and dry at 80°C to obtain composite particles.

3. The flame retardant and noise reducing polyethylene drainage pipe according to claim 2, characterized in that: The other organic silicon compound is at least one of dimethyldiethoxysilane, methyltriethoxysilane, triethoxypentylsilane, n-octyltriethoxysilane and n-hexyltriethoxysilane.

4. The flame retardant and noise reducing polyethylene drainage pipe according to claim 2, characterized in that: The ethanol aqueous solution is a mixture of ethanol and water in a volume ratio of 2-3:1; The dosage ratio of barium sulfate and ethanol aqueous solution is 1g:4-5mL; The mass ratio of barium sulfate, ethyl orthosilicate and other organic silicon compounds is 5-6:1-2:1-2; The barium sulfate powder is 1200-1300 mesh.

5. The flame retardant and noise reducing polyethylene drainage pipe according to claim 1, characterized in that: The PE flame retardant outer layer and the PE flame retardant inner layer are prepared from the following raw materials in parts by weight: 35-60 parts of high-density polyethylene and 40-65 parts of flame retardant masterbatch.

6. A flame retardant and noise reducing polyethylene drainage pipe according to claim 1 or 5, characterized in that: The flame retardant masterbatch is prepared by melting, shearing, blending, extruding and granulating 30-50 parts of high-density polyethylene, 50-70 parts of compound flame retardant powder, 0.1-0.8 parts of antioxidant, 0.5-2 parts of coupling agent and 0.2-1 parts of lubricant according to weight.

7. The flame retardant and noise reducing polyethylene drainage pipe according to claim 6, characterized in that: The compound flame retardant powder comprises piperazine pyrophosphate, melamine polyphosphate and hypophosphite, wherein the hypophosphite is one of diethyl aluminum hypophosphite, diethyl cerium hypophosphite, diethyl calcium hypophosphite, dipropyl aluminum hypophosphite and methyl ethyl aluminum hypophosphite.

8. The flame retardant and noise reducing polyethylene drainage pipe according to claim 7, characterized in that: The mass ratio of piperazine pyrophosphate, melamine polyphosphate and hypophosphite is 5-7:3-5:

1.

9. The flame retardant and noise reducing polyethylene drainage pipe according to claim 6, characterized in that: The antioxidant is one of antioxidant 1010, antioxidant 168, antioxidant 1076 and antioxidant 626; The coupling agent is one of KH550, KH560 and KH570 coupling agents; The lubricant is at least one of erucamide, ethylene bis stearamide, pentaerythritol stearate and polyethylene wax.

10. The flame retardant and noise reducing polyethylene drainage pipe according to claim 1, characterized in that: The thickness ratio of the PE flame retardant outer layer, the PE flame retardant noise reduction middle layer and the PE flame retardant inner layer is (0.8-2):(6-8):(0.8-2).

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