A low-noise drain pipe and a method for manufacturing the same

Abstract

The application discloses a low-noise drainage pipe and a preparation method thereof, and belongs to the technical field of drainage pipes. The low-noise drainage pipe comprises, from inside to outside, a sound insulation inner layer, a bonding layer, a noise reduction middle layer and a protective outer layer. The raw material of the sound insulation inner layer comprises, in weight parts, 100-110 parts of polyethylene resin, 10-25 parts of water absorption resin, 3-5 parts of a compatibilizer, 5-10 parts of graphene oxide, 0.5-1 part of a first lubricant, 0.1-0.2 parts of a main antioxidant and 0.1-0.2 parts of an auxiliary antioxidant. In addition, the application further provides a preparation method of the low-noise drainage pipe. The low-noise drainage pipe is formed by the noise reduction effect of the two layers, and can comprehensively block the noise of high, medium and low frequencies, and the effect is more obvious than that of a traditional pipe.

Description

Technical Field

[0001] This invention relates to the field of drainage pipe technology, specifically to a low-noise drainage pipe and its manufacturing method. Background Technology

[0002] The noise generated by plastic drainage pipes is caused by several factors. First, the high-speed flow of sewage within the pipe creates shear friction against the pipe wall, resulting in turbulent and eddy currents. The collisions between these currents convert energy into sound waves, primarily high-frequency noise. Second, during drainage from high-rise buildings, the free-falling water impacts the pipe wall, elbows, tees, inspection ports, and large bends at the bottom, creating instantaneous impact force, primarily producing mid-to-low frequency sound. Third, during drainage, the downward flow of water compresses and drags air, creating negative pressure within the pipe. The sudden compression and bursting of air produces a bursting sound, primarily mid-to-low frequency. Fourth, the impact of water flow and bursting air exert periodic excitation forces on the pipe material. When this periodic excitation force is approximately equal to the pipe's natural frequency, resonance amplification occurs, causing the pipe wall to vibrate like a drum, primarily producing low-frequency sound.

[0003] Regarding noise reduction, the domestic high-end market currently mainly uses polypropylene and polyethylene silent drainage pipes. Patent CN201711480385.6 discloses a flame-retardant, high-temperature resistant reinforced polypropylene silent drainage pipe and its application. This patent increases the density of the polypropylene silent drainage pipe by adding barium sulfate and glass fiber to the middle layer to achieve noise reduction. However, its long-term noise reduction effect is poor, and its low-temperature impact resistance is also poor. Patent CN223609547 U discloses a silent composite pipe and conveying system. This patent uses high-density polyethylene material, with a microporous foamed middle layer and corona-electrode pores in the inner layer to form a resonant microporous structure to achieve noise reduction. However, it can only absorb low-frequency noise, and its noise reduction effect is limited. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a low-noise drainage pipe and its preparation method, thereby solving the technical problem of how to achieve comprehensive blocking of high, medium and low frequency noise in the prior art.

[0005] To achieve the above-mentioned technical objectives, the present invention provides a low-noise drainage pipe, which comprises, from the inside out, a sound-insulating inner layer, an adhesive layer, a noise-reducing middle layer, and a protective outer layer; the raw materials of the sound-insulating inner layer, calculated by weight, include: 100-110 parts of polyethylene resin, 10-25 parts of water-absorbing resin, 3-5 parts of compatibilizer, 5-10 parts of graphene oxide, 0.5-1 part of first lubricant, 0.1-0.2 parts of main antioxidant, and 0.1-0.2 parts of auxiliary antioxidant.

[0006] In any embodiment, the water-absorbing resin is sodium polyacrylate water-absorbing resin; and / or, the compatibilizer is one or both of maleic anhydride-grafted polyethylene and glycidyl methacrylate-grafted polyethylene; and / or, the first lubricant is one or more of polyethylene wax, oxidized polyethylene wax and paraffin wax; and / or, the primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; and / or, the secondary antioxidant is tris[2,4-di-tert-butylphenyl] phosphite.

[0007] In any embodiment, the raw materials of the noise-reducing middle layer, calculated by weight, include: 100-110 parts of acrylic copolymer polyvinyl chloride resin, 20-50 parts of the first filler, 2.0-3.5 parts of the first calcium-zinc stabilizer, 0.5-1.5 parts of the second lubricant, 5-10 parts of color powder, 1-2 parts of the first processing modifier, and 5-10 parts of the first impact modifier; and / or, the raw materials of the protective outer layer, calculated by weight, include: 100-110 parts of acrylic copolymer polyvinyl chloride resin, 3-8 parts of the second filler, 2.5-4.0 parts of the second calcium-zinc stabilizer, 0.5-1.5 parts of the third lubricant, 5-10 parts of color powder, 1-2 parts of the second processing modifier, and 5-10 parts of the second impact modifier.

[0008] In any embodiment, the first filler or the second filler is one or more of barium sulfate, glass fiber powder, glass microspheres, montmorillonite, mica powder, talc powder, calcium carbonate, and calcium sulfate.

[0009] In any embodiment, the second lubricant or the third lubricant is one or more of stearic acid, calcium stearate, polyethylene wax, oxidized polyethylene wax and paraffin.

[0010] In any embodiment, the first processing modifier or the second processing modifier is a methyl methacrylate-acrylate copolymer.

[0011] In any embodiment, the first impact modifier or the second impact modifier is one of chlorinated polyvinyl chloride, methyl methacrylate-butadiene-styrene terpolymer, or acrylonitrile-butadiene-styrene copolymer.

[0012] In any embodiment, the thickness ratio of the four layers—the sound-insulating inner layer, the adhesive layer, the noise-reducing middle layer, and the protective outer layer—is (4-7):(0.5-1):(30-40):(4-7).

[0013] Furthermore, the present invention also proposes a method for preparing the above-mentioned low-noise drainage pipe, comprising the following steps: S1. The raw materials for the sound insulation inner layer, noise reduction middle layer, and protective outer layer are respectively put into a high-speed mixing unit for mixing. First, hot mixing is carried out, then cold mixing is carried out, and finally, after screening and maturation, the sound insulation inner layer mixture, noise reduction middle layer mixture, and protective outer layer mixture are obtained. S2. The prepared sound-insulating inner layer compound is granulated using a parallel twin-screw extruder, and the noise-reducing middle layer compound and the protective outer layer compound are granulated using a conical twin-screw extruder to obtain the corresponding inner layer granules, middle layer granules, and outer layer granules. The barrel temperature of the parallel twin-screw extruder is 175-180℃, and the die exit temperature is 195-200℃; the barrel temperature of the conical twin-screw extruder is 165-170℃, and the die exit temperature is 190-195℃. S3. The inner layer granules, the middle layer granules, the outer layer granules, and the adhesive layer raw materials are fed together into a parallel single-screw pipe extruder and compounded in a multi-layer co-extrusion die to prepare a billet; S4: The blank enters the vacuum shaping and cooling box and is cooled and shaped by internal pressure and external sizing to obtain the low-noise drainage pipe.

[0014] In any embodiment, in step S3, the barrel temperature of the conical twin-screw sound-insulating inner layer extruder is 175-178°C, the barrel temperature of the noise-reducing middle layer extruder is 172-175°C, the barrel temperature of the adhesive layer extruder is 170-173°C, the barrel temperature of the protective outer layer extruder is 172-175°C, and the temperature at the die exit is 195-200°C.

[0015] Compared with existing technologies, the beneficial effects of this invention include: The low-noise drainage pipe proposed in this invention increases the surface density of the pipe by adding inorganic filler to the noise-reducing middle layer, converting vibration sound into heat energy consumption and preventing sound wave penetration. Simultaneously, water-absorbing resin material is added to the sound-insulating inner layer. Through the cross-linked network structure and the formed negatively charged groups, water molecules are absorbed into the interior and cannot be squeezed out. Furthermore, the molecules form a large number of pores, making it easier for water molecules to enter and increasing the water absorption capacity. Therefore, compared with traditional silent drainage pipes, the micropores and electronegativity of the inner wall make it easier to form a vacuum adsorption effect on the inner surface, resulting in lower frictional resistance, significantly increasing drainage flow and reducing noise. Through the composite noise reduction effect between the two layers, comprehensive blocking of high, medium, and low frequency noise is achieved, which is more effective than traditional pipes.

[0016] In addition, the present invention introduces acrylic copolymer polyvinyl chloride material into the protective outer layer and the noise reduction middle layer. It is formed by fully integrating ultra-fine acrylic elastomer components into vinyl chloride to form a chemical bond. Therefore, the pipe has good low-temperature impact resistance, low coefficient of linear expansion and high ring stiffness. Attached Figure Description

[0017] Figure 1This is a photograph of the low-noise drainage pipe obtained in Embodiment 1 of the present invention. Detailed Implementation

[0018] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0019] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0020] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0021] This specific embodiment provides a low-noise drainage pipe, comprising, from the inside out, a sound-insulating inner layer, an adhesive layer, a noise-reducing middle layer, and a protective outer layer. The raw materials of the sound-insulating inner layer, calculated by weight, include: 100-110 parts polyethylene resin, 10-25 parts water-absorbing resin, 3-5 parts compatibilizer, 5-10 parts graphene oxide, 0.5-1 part first lubricant, 0.1-0.2 parts main antioxidant, and 0.1-0.2 parts auxiliary antioxidant. The water-absorbing resin is sodium polyacrylate water-absorbing resin; the compatibilizer is maleic anhydride grafted. One or both of polyethylene and glycidyl methacrylate grafted polyethylene; the first lubricant is one or more of polyethylene wax, oxidized polyethylene wax and paraffin wax; the main antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; the auxiliary antioxidant is tris[2,4-di-tert-butylphenyl] phosphite; the thickness ratio of the four layers of the sound insulation inner layer, the adhesive layer, the noise reduction middle layer and the protective outer layer is (4-7):(0.5-1):(30-40):(4-7).

[0022] In some embodiments, the raw materials of the noise-reducing middle layer, calculated by weight, include: 100-110 parts of acrylic copolymer polyvinyl chloride resin, 20-50 parts of the first filler, 2.0-3.5 parts of the first calcium-zinc stabilizer, 0.5-1.5 parts of the second lubricant, 5-10 parts of color powder, 1-2 parts of the first processing modifier, and 5-10 parts of the first impact modifier; the raw materials of the protective outer layer, calculated by weight, include: 100-110 parts of acrylic copolymer polyvinyl chloride resin, 3-8 parts of the second filler, 2.5-4.0 parts of the second calcium-zinc stabilizer, 0.5-1.5 parts of the third lubricant, 5-10 parts of color powder, 1-2 parts of the second processing modifier, and 5-10 parts of the second impact modifier.

[0023] In some embodiments, the first filler or the second filler is one or more of barium sulfate, glass fiber powder, glass microspheres, montmorillonite, mica powder, talc powder, calcium carbonate, and calcium sulfate; the second lubricant or the third lubricant is one or more of stearic acid, calcium stearate, polyethylene wax, oxidized polyethylene wax, and paraffin wax; the first processing modifier or the second processing modifier is methyl methacrylate-acrylate copolymer; the first impact modifier or the second impact modifier is one of chlorinated polyvinyl chloride, methyl methacrylate-butadiene-styrene terpolymer, and acrylonitrile-butadiene-styrene copolymer.

[0024] This specific embodiment also proposes a method for preparing the above-mentioned low-noise drainage pipe, including the following steps: S1. Weigh out the raw materials for the sound insulation inner layer, noise reduction middle layer, and protective outer layer respectively. Put the weighed raw materials into the high-speed mixing unit for mixing. First, perform hot mixing, then cold mixing, and finally, after screening and maturation, prepare the sound insulation inner layer mixture, noise reduction middle layer mixture, and protective outer layer mixture. S2. The prepared sound-insulating inner layer compound is granulated using a parallel twin-screw extruder, and the noise-reducing middle layer compound and the protective outer layer compound are granulated using a conical twin-screw extruder to obtain the corresponding inner layer granules, middle layer granules, and outer layer granules. The barrel temperature of the parallel twin-screw extruder is 175-180℃, and the die exit temperature is 195-200℃; the barrel temperature of the conical twin-screw extruder is 165-170℃, and the die exit temperature is 190-195℃. S3. The inner layer granules, middle layer granules, outer layer granules, and adhesive layer raw materials are fed together into a parallel single-screw pipe extruder and compounded in a multi-layer co-extrusion die to prepare a billet. The barrel temperature of the conical twin-screw sound-insulating inner layer extruder is 175-178℃, the barrel temperature of the noise-reducing middle layer extruder is 172-175℃, the barrel temperature of the adhesive layer extruder is 170-173℃, the barrel temperature of the protective outer layer extruder is 172-175℃, and the temperature at the die exit is 195-200℃. S4: The blank enters the vacuum shaping and cooling box and is cooled and shaped by internal pressure and external sizing to obtain the low-noise drainage pipe.

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0027] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0028] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0029] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0030] Example 1

[0031] This embodiment proposes a low-noise drainage pipe, which comprises, from the inside out, a sound-insulating inner layer, an adhesive layer, a noise-reducing middle layer, and a protective outer layer; the thickness ratio of the four layers is 5:0.6:30:5; the adhesive layer is made of maleic anhydride-grafted ethylene-vinyl acetate copolymer. A photograph of the low-noise drainage pipe is shown below. Figure 1 As shown.

[0032] The raw materials of the sound insulation inner layer, calculated by weight, include: 100 parts high-density polyethylene resin, 25 parts water-absorbing resin, 5 parts compatibilizer, 5 parts graphene oxide, 1 part lubricant, 0.2 parts primary antioxidant, and 0.1 parts secondary antioxidant. The water-absorbing resin of the sound insulation inner layer is sodium polyacrylate water-absorbing resin, the compatibilizer of the sound insulation inner layer is maleic anhydride-grafted polyethylene, the lubricant of the sound insulation inner layer is polyethylene wax, the primary antioxidant of the sound insulation inner layer is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the secondary antioxidant of the sound insulation inner layer is tris[2,4-di-tert-butylphenyl] phosphite.

[0033] The raw materials of the noise-reducing middle layer, calculated by weight, include: 100 parts of acrylic copolymer polyvinyl chloride resin, 25 parts of filler, 2.8 parts of calcium zinc stabilizer, 1.5 parts of lubricant, 6 parts of color powder, 1 part of processing modifier, and 5 parts of impact modifier; the filler of the noise-reducing middle layer is barium sulfate, the filler of the protective outer layer is calcium carbonate, and the lubricant of the noise-reducing middle layer is 1 part of calcium stearate and 0.5 parts of polyethylene wax.

[0034] The raw materials of the protective outer layer, calculated by weight, include: 100 parts acrylic copolymer polyvinyl chloride resin, 6 parts filler, 3.0 parts calcium zinc stabilizer, 1.0 part lubricant, 6 parts color powder, 1 part processing modifier and 7 parts impact modifier; the lubricant of the protective outer layer is 0.5 parts stearic acid and 0.5 parts polyethylene wax.

[0035] The processing modifier in the noise-reducing middle layer and the protective outer layer is a methyl methacrylate-acrylate copolymer; the impact-resistant modifier in the noise-reducing middle layer and the protective outer layer is a methyl methacrylate-butadiene-styrene terpolymer.

[0036] This embodiment also proposes a method for preparing the above-mentioned low-noise drainage pipe, including the following steps: S1. Weigh the raw materials for the sound insulation inner layer, noise reduction middle layer and protective outer layer respectively, put the weighed raw materials into the high-speed mixing unit for mixing, first hot mixing, then cold mixing, and finally sieve and mature to prepare modified polyethylene inner layer compound, acrylic copolymer polyvinyl chloride noise reduction middle layer compound and acrylic copolymer polyvinyl chloride protective outer layer compound. S2. The prepared modified polyethylene inner layer compound is granulated using a parallel twin-screw extruder, and the acrylic copolymer PVC noise-reducing middle layer compound and the acrylic copolymer PVC protective outer layer compound are granulated using a conical twin-screw extruder to obtain the corresponding inner layer granules, middle layer granules, and outer layer granules. The barrel temperature of the parallel twin-screw extruder is 180℃, and the die exit temperature is 200℃; the barrel temperature of the conical twin-screw extruder is 170℃, and the die exit temperature is 195℃. S3. The raw materials of the inner layer granules, middle layer granules, outer layer granules and adhesive layer are fed together into a parallel single-screw pipe extruder and compounded in a multi-layer co-extrusion die to prepare a billet; the barrel temperature of the conical twin-screw sound-insulating inner layer extruder is 180℃, the barrel temperature of the noise-reducing middle layer extruder is 180℃, the barrel temperature of the adhesive layer extruder is 170℃, the barrel temperature of the protective outer layer extruder is 180℃, and the temperature at the die exit is 200℃; S4. The billet enters the vacuum shaping and cooling box and is cooled and shaped by internal pressure and external sizing to produce a low-noise drainage pipe.

[0037] Example 2

[0038] This embodiment proposes a low-noise drainage pipe, which includes, from the inside out, a sound-insulating inner layer, an adhesive layer, a noise-reducing middle layer, and a protective outer layer; the thickness ratio of the sound-insulating inner layer, adhesive layer, noise-reducing middle layer, and protective outer layer is 5:0.6:35:5; the raw material of the adhesive layer is maleic anhydride-grafted ethylene-vinyl acetate copolymer.

[0039] The raw materials of the sound insulation inner layer, calculated by weight, include: 100 parts high-density polyethylene resin, 25 parts water-absorbing resin, 5 parts compatibilizer, 5 parts graphene oxide, 1 part lubricant, 0.2 parts primary antioxidant, and 0.1 parts secondary antioxidant. The water-absorbing resin of the sound insulation inner layer is sodium polyacrylate water-absorbing resin, the compatibilizer of the sound insulation inner layer is glycidyl methacrylate-grafted polyethylene, the lubricant of the sound insulation inner layer is paraffin wax, the primary antioxidant of the sound insulation inner layer is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the secondary antioxidant of the sound insulation inner layer is tris[2,4-di-tert-butylphenyl] phosphite.

[0040] The raw materials of the noise reduction middle layer, calculated by weight, include: 100 parts of acrylic copolymer polyvinyl chloride resin, 50 parts of filler, 2.5 parts of calcium zinc stabilizer, 1.2 parts of lubricant, 6 parts of color powder, 1 part of processing modifier, and 8 parts of impact modifier.

[0041] The raw materials of the protective outer layer, calculated by weight, include: 100 parts acrylic copolymer polyvinyl chloride resin, 6 parts filler, 3.0 parts calcium zinc stabilizer, 1.0 part lubricant, 6 parts color powder, 1 part processing modifier, and 7 parts impact modifier.

[0042] The filler for the noise-reducing middle layer is 30 parts barium sulfate and 20 parts glass fiber powder; the filler for the protective outer layer is calcium carbonate; the lubricant for the noise-reducing middle layer is 0.8 parts calcium stearate and 0.4 parts polyethylene wax; the lubricant for the protective outer layer is 1 part stearic acid and 0.5 parts polyethylene wax; the processing modifier for the noise-reducing middle layer and the protective outer layer is methyl methacrylate-acrylate copolymer; the impact modifier for the noise-reducing middle layer and the protective outer layer is methyl methacrylate-butadiene-styrene terpolymer.

[0043] This embodiment also proposes a method for preparing a low-noise drainage pipe, including the following steps: S1. Weigh the raw materials for the sound insulation inner layer, noise reduction middle layer, and protective outer layer respectively, and put the weighed raw materials into the high-speed mixing unit for mixing. First, perform hot mixing, then cold mixing, and finally, after screening and maturation, prepare the modified polyethylene inner layer compound, the acrylic copolymer polyvinyl chloride noise reduction middle layer compound, and the acrylic copolymer polyvinyl chloride protective outer layer compound. S2. The prepared modified polyethylene inner layer compound is granulated using a parallel twin-screw extruder, and the acrylic copolymer PVC noise-reducing middle layer compound and the acrylic copolymer PVC protective outer layer compound are granulated using a conical twin-screw extruder to obtain the corresponding inner layer granules, middle layer granules, and outer layer granules. The barrel temperature of the parallel twin-screw extruder is 180℃, and the die exit temperature is 200℃; the barrel temperature of the conical twin-screw extruder is 170℃, and the die exit temperature is 195℃. S3. The raw materials of the inner layer granules, middle layer granules, outer layer granules and adhesive layer are fed together into a parallel single-screw pipe extruder and compounded in a multi-layer co-extrusion die to prepare a billet; the barrel temperature of the conical twin-screw sound-insulating inner layer extruder is 178℃, the barrel temperature of the noise-reducing middle layer extruder is 180℃, the barrel temperature of the adhesive layer extruder is 170℃, the barrel temperature of the protective outer layer extruder is 175℃, and the temperature at the die exit is 200℃; S4. The billet enters the vacuum shaping and cooling box and is cooled and shaped by internal pressure and external sizing to produce a low-noise drainage pipe.

[0044] Example 3

[0045] This embodiment proposes a low-noise drainage pipe, which includes, from the inside out, a sound-insulating inner layer, an adhesive layer, a noise-reducing middle layer, and a protective outer layer; the thickness ratio of the sound-insulating inner layer, adhesive layer, noise-reducing middle layer, and protective outer layer is 6:0.6:30:6; the raw material of the adhesive layer is maleic anhydride-grafted ethylene-vinyl acetate copolymer.

[0046] The raw materials of the sound insulation inner layer, calculated by weight, include: 100 parts of high-density polyethylene resin, 20 parts of water-absorbing resin, 5 parts of compatibilizer, 7 parts of graphene oxide, 0.8 parts of lubricant, 0.2 parts of main antioxidant and 0.1 parts of auxiliary antioxidant.

[0047] The raw materials of the noise reduction middle layer, calculated by weight, include: 100 parts acrylic copolymer polyvinyl chloride resin, 50 parts filler, 2.5 parts calcium zinc stabilizer, 1.2 parts lubricant, 6 parts color powder, 1 part processing modifier, and 8 parts impact modifier.

[0048] The raw materials of the protective outer layer, calculated by weight, include: 100 parts acrylic copolymer polyvinyl chloride resin, 6 parts filler, 3.0 parts calcium zinc stabilizer, 1.0 part lubricant, 6 parts color powder, 1 part processing modifier, and 7 parts impact modifier.

[0049] The water-absorbing resin of the sound insulation inner layer is sodium polyacrylate water-absorbing resin; the compatibilizer of the sound insulation inner layer is glycidyl methacrylate grafted polyethylene; the lubricant of the sound insulation inner layer is polyethylene wax; the main antioxidant of the sound insulation inner layer is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; and the auxiliary antioxidant of the sound insulation inner layer is tris[2,4-di-tert-butylphenyl] phosphite.

[0050] The filler for the noise-reducing middle layer is 40 parts barium sulfate and 10 parts mica powder; the filler for the protective outer layer is calcium sulfate; the lubricant for the noise-reducing middle layer is 0.8 parts calcium stearate and 0.4 parts polyethylene wax; the lubricant for the protective outer layer is 1 part stearic acid and 0.5 parts polyethylene wax; the processing modifier for the noise-reducing middle layer and the protective outer layer is methyl methacrylate-acrylate copolymer; and the impact modifier for the noise-reducing middle layer and the protective outer layer is methyl methacrylate-butadiene-styrene terpolymer.

[0051] This embodiment also proposes a method for preparing the above-mentioned low-noise drainage pipe, including the following steps: S1. Weigh the raw materials for the sound insulation inner layer, noise reduction middle layer, and protective outer layer respectively, and put the weighed raw materials into the high-speed mixing unit for mixing. First, perform hot mixing, then cold mixing, and finally, after screening and maturation, prepare the modified polyethylene inner layer compound, the acrylic copolymer polyvinyl chloride noise reduction middle layer compound, and the acrylic copolymer polyvinyl chloride protective outer layer compound. S2. The prepared modified polyethylene inner layer compound is granulated using a parallel twin-screw extruder, and the acrylic copolymer PVC noise-reducing middle layer compound and the acrylic copolymer PVC protective outer layer compound are granulated using a conical twin-screw extruder to obtain the corresponding inner layer granules, middle layer granules, and outer layer granules. The barrel temperature of the parallel twin-screw extruder is 180℃, and the die exit temperature is 200℃; the barrel temperature of the conical twin-screw extruder is 170℃, and the die exit temperature is 195℃. S3. The raw materials of the inner layer granules, middle layer granules, outer layer granules and adhesive layer are fed together into a parallel single-screw pipe extruder and compounded in a multi-layer co-extrusion die to prepare a billet; the barrel temperature of the conical twin-screw sound-insulating inner layer extruder is 178℃, the barrel temperature of the noise-reducing middle layer extruder is 175℃, the barrel temperature of the adhesive layer extruder is 173℃, the barrel temperature of the protective outer layer is 175℃, and the temperature at the die exit is 200℃; S4. The billet enters the vacuum shaping and cooling box and is cooled and shaped by internal pressure and external sizing to produce a low-noise drainage pipe.

[0052] Comparative Example 1: No water-absorbing resin added This comparative example proposes a low-noise drainage pipe. The difference from Example 1 is that the material of the sound-insulating inner layer does not contain the water-absorbing resin of Example 1, but replaces the water-absorbing resin with an equal amount of high-density polyethylene resin. All other raw materials and components are the same as in Example 1.

[0053] Specifically, the raw materials of the sound insulation inner layer, calculated by weight, include: 125 parts high-density polyethylene resin, 5 parts compatibilizer, 5 parts graphene oxide, 1 part lubricant, 0.2 parts primary antioxidant, and 0.1 parts secondary antioxidant; the compatibilizer of the sound insulation inner layer is maleic anhydride-grafted polyethylene, the lubricant of the sound insulation inner layer is polyethylene wax, the primary antioxidant of the sound insulation inner layer is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the secondary antioxidant of the sound insulation inner layer is tris[2,4-di-tert-butylphenyl] phosphite.

[0054] The preparation method of the low-noise drainage pipe in this comparative example is the same as that in Example 1.

[0055] Comparative Example 2 This comparative example proposes a low-noise drainage pipe, which includes an inner layer, a noise-reducing middle layer, and a protective outer layer from the inside out; the thickness ratio of the three layers is 0.6:3:0.6.

[0056] The raw materials and dosage of the inner layer are the same as those of the noise reduction middle layer; the raw materials of the noise reduction middle layer, calculated by weight, include: 100 parts of acrylic copolymer polyvinyl chloride resin, 25 parts of filler, 2.8 parts of calcium zinc stabilizer, 1.5 parts of lubricant, 6 parts of color powder, 1 part of processing modifier, and 5 parts of impact modifier.

[0057] The raw materials of the protective outer layer, calculated by weight, include: 100 parts acrylic copolymer polyvinyl chloride resin, 6 parts filler, 3.0 parts calcium zinc stabilizer, 1.0 part lubricant, 6 parts color powder, 1 part processing modifier, and 7 parts impact modifier.

[0058] The filler for the noise-reducing middle layer is barium sulfate, and the filler for the protective outer layer is calcium carbonate; the lubricant for the noise-reducing middle layer is 1.0 part calcium stearate and 0.5 parts polyethylene wax; the lubricant for the protective outer layer is 0.5 parts stearic acid and 0.5 parts polyethylene wax.

[0059] The processing modifier for the noise-reducing middle layer and the protective outer layer is methyl methacrylate-acrylate copolymer; the impact-resistant modifier for the noise-reducing middle layer and the protective outer layer is methyl methacrylate-butadiene-styrene terpolymer.

[0060] The preparation method of the low-noise drainage pipe in this comparative example includes the following steps: S1: Weigh the raw materials for the inner layer, noise reduction middle layer, and protective outer layer respectively, and put the weighed raw materials into the high-speed mixing unit for mixing. First, perform hot mixing, then cold mixing, and finally, after screening and maturation, prepare the acrylic copolymer polyvinyl chloride noise reduction middle layer mixture, as well as the acrylic copolymer polyvinyl chloride inner layer mixture and the protective outer layer mixture. S2: The prepared acrylic copolymer polyvinyl chloride noise reduction middle layer compound, acrylic copolymer polyvinyl chloride inner layer compound, and protective outer layer compound are granulated through a conical twin-screw extruder to obtain the corresponding granulated material. The barrel temperature of the conical twin-screw extruder is 170℃, and the temperature at the die exit is 195℃. S3: The acrylic copolymer PVC noise reduction middle layer granules, acrylic copolymer PVC inner layer granules, and protective outer layer granules are then fed into a conical twin-screw pipe extruder and compounded in a three-layer co-extrusion die to prepare the billet; the barrel temperature of the conical twin-screw sound insulation inner layer extruder is 180℃, the barrel temperature of the noise reduction middle layer extruder is 180℃, the barrel temperature of the inner layer and the protective outer layer is 180℃, and the temperature at the die exit is 200℃.

[0061] S4: The billet enters the vacuum shaping and cooling box and is cooled and shaped by internal pressure and external sizing to produce a low-noise drainage pipe.

[0062] Following the above embodiments and comparative examples, DN110 x 4.2 mm pipes were prepared, and their performance was tested as follows. Test method: According to GB / T312-2009 "Noise Test of Building Drainage Piping System (Structural Sound)", the test was conducted on the Vanke Test Tower without the addition of foam or other coverings. The results are shown in Table 1.

[0063] Table 1

[0064] The ring stiffness, impact resistance, and coefficient of linear expansion of thermoplastic pipes were tested according to GB / T 9647-2015 "Determination of ring stiffness of thermoplastic pipes", GB / T 14152 "Test method for impact resistance of thermoplastic pipes - clockwise rotation method", and GB / T 1036-2008 "Determination of coefficient of linear expansion of plastics at -30℃ - 30℃ - quartz dilatometer method". The results are shown in Table 2.

[0065] Table 2

[0066] Combining Tables 1 and 2, the low-noise drainage pipe proposed in the embodiments has a significant noise reduction effect. It has a lower sound pressure level than polypropylene silent drainage pipes, polyethylene silent drainage pipes, and cast iron pipes on the market, and also has a lower coefficient of linear expansion, better low-temperature impact resistance, and higher ring stiffness.

[0067] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A low-noise drainage pipe, characterized in that, From the inside out, it includes a sound-insulating inner layer, an adhesive layer, a noise-reducing middle layer, and a protective outer layer. The raw materials of the sound-insulating inner layer, calculated by weight, include: 100-110 parts of polyethylene resin, 10-25 parts of water-absorbing resin, 3-5 parts of compatibilizer, 5-10 parts of graphene oxide, 0.5-1 part of primary lubricant, 0.1-0.2 parts of primary antioxidant, and 0.1-0.2 parts of secondary antioxidant.

2. The low-noise drainage pipe according to claim 1, characterized in that, The water-absorbing resin is sodium polyacrylate water-absorbing resin; and / or, the compatibilizer is one or both of maleic anhydride-grafted polyethylene and glycidyl methacrylate-grafted polyethylene; and / or, the first lubricant is one or more of polyethylene wax, oxidized polyethylene wax and paraffin wax; and / or, the primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; and / or, the secondary antioxidant is tris[2,4-di-tert-butylphenyl] phosphite.

3. The low-noise drainage pipe according to claim 1, characterized in that, The raw materials of the noise-reducing middle layer, calculated by weight, include: 100-110 parts of acrylic copolymer polyvinyl chloride resin, 20-50 parts of the first filler, 2.0-3.5 parts of the first calcium-zinc stabilizer, 0.5-1.5 parts of the second lubricant, 5-10 parts of color powder, 1-2 parts of the first processing modifier, and 5-10 parts of the first impact modifier; and / or, the raw materials of the protective outer layer, calculated by weight, include: 100-110 parts of acrylic copolymer polyvinyl chloride resin, 3-8 parts of the second filler, 2.5-4.0 parts of the second calcium-zinc stabilizer, 0.5-1.5 parts of the third lubricant, 5-10 parts of color powder, 1-2 parts of the second processing modifier, and 5-10 parts of the second impact modifier.

4. The low-noise drainage pipe according to claim 3, characterized in that, The first filler or the second filler is one or more of barium sulfate, glass fiber powder, glass microspheres, montmorillonite, mica powder, talc powder, calcium carbonate and calcium sulfate.

5. The low-noise drainage pipe according to claim 3, characterized in that, The second or third lubricant is one or more of stearic acid, calcium stearate, polyethylene wax, oxidized polyethylene wax and paraffin.

6. The low-noise drainage pipe according to claim 3, characterized in that, The first processing modifier or the second processing modifier is a methyl methacrylate-acrylate copolymer.

7. The low-noise drainage pipe according to claim 3, characterized in that, The first or second impact modifier is one of chlorinated polyvinyl chloride, methyl methacrylate-butadiene-styrene terpolymer, or acrylonitrile-butadiene-styrene copolymer.

8. The low-noise drainage pipe according to claim 1, characterized in that, The thickness ratio of the four layers—the inner sound insulation layer, the adhesive layer, the middle noise reduction layer, and the outer protective layer—is (4-7):(0.5-1):(30-40):(4-7).

9. A method for preparing a low-noise drainage pipe according to any one of claims 1-8, characterized in that, Includes the following steps: S1. The raw materials for the sound insulation inner layer, noise reduction middle layer, and protective outer layer are respectively put into a high-speed mixing unit for mixing. First, hot mixing is carried out, then cold mixing is carried out, and finally, after screening and maturation, the sound insulation inner layer mixture, noise reduction middle layer mixture, and protective outer layer mixture are obtained. S2. The prepared sound-insulating inner layer compound is granulated using a parallel twin-screw extruder, and the noise-reducing middle layer compound and the protective outer layer compound are granulated using a conical twin-screw extruder to obtain the corresponding inner layer granules, middle layer granules, and outer layer granules. The barrel temperature of the parallel twin-screw extruder is 175-180℃, and the die exit temperature is 195-200℃; the barrel temperature of the conical twin-screw extruder is 165-170℃, and the die exit temperature is 190-195℃. S3. The inner layer granules, the middle layer granules, the outer layer granules, and the adhesive layer raw materials are fed together into a parallel single-screw pipe extruder and compounded in a multi-layer co-extrusion die to prepare a billet; S4: The blank enters the vacuum shaping and cooling box and is cooled and shaped by internal pressure and external sizing to obtain the low-noise drainage pipe.

10. The preparation method according to claim 9, characterized in that, In step S3, the barrel temperature of the conical twin-screw sound-insulating inner layer extruder is 175-178℃, the barrel temperature of the noise-reducing middle layer extruder is 172-175℃, the barrel temperature of the adhesive layer extruder is 170-173℃, the barrel temperature of the protective outer layer extruder is 172-175℃, and the temperature at the die exit is 195-200℃.

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