Thirteen-hole plastic pipe for power communication protection and preparation method thereof

Abstract

The present application relates to the field of electric power communication protection pipe material, disclose a kind of thirteen hole electric power communication protection plastic pipe material and preparation method thereof, the plastic pipe material is by modified polyvinyl chloride composition thirteen hole composite forming die integrated extrusion molding;The modified polyvinyl chloride composition includes the following weight parts of components: PVC resin 60-80 parts, CPVC resin 20-40 parts, MBS impact agent 8-16 parts, chlorinated polyethylene and / or chlorinated polypropylene 4-10 parts, epoxy resin E51 0.8-2.5 parts, silane modified composite filler 10-18 parts, calcium-zinc composite stabilizer 4-7 parts, ACR processing aid 3-7 parts, internal lubricant 0.8-1.8 parts, external lubricant 1.2-2.8 parts and high temperature lubrication regulator 0.3-0.8 parts;The silane modified composite filler includes superfine calcium carbonate and organic modified montmorillonite, and the epoxy resin E51 is loaded on the surface of the silane modified composite filler.The present application realizes the stable extrusion molding of thirteen hole complex thin-walled structure electric power communication protection pipe, and improves the hole type consistency, interface bonding strength and processing stability of porous structure.

Description

Technical Field

[0001] This invention relates to the field of power communication protection pipe technology, and in particular to a thirteen-hole power communication protection plastic pipe and its preparation method. Background Technology

[0002] With the upgrading of power systems and the rapid development of communication networks, the scale of underground laying of power cables, communication optical cables, and control cables is constantly expanding. As an important infrastructure for cable laying, power and communication protection pipes must meet comprehensive performance requirements such as multi-cable zone laying, insulation protection, compressive strength, corrosion resistance, and long-term service stability. To improve the space utilization efficiency of underground pipe corridors, existing projects are gradually adopting multi-hole structure pipes to replace traditional single-hole protection pipes, so as to achieve the separate laying of multiple cables in the same pipe.

[0003] Existing multi-hole power and communication protection pipes mostly adopt honeycomb, cloverleaf, or grid pipe structures, which achieve cable partitioning by setting multiple through holes in a single pipe body. However, due to the large number of internal ribs, thin hole walls, and complex flow channels in the multi-hole structure, problems such as uneven melt distribution, insufficient local filling, rib breakage, low weld line strength, and out-of-roundness of the hole shape are prone to occur during the extrusion molding process. Under external loads or the compaction of backfill soil, multi-hole structures are also prone to local collapse or deformation between holes, affecting cable installation efficiency and long-term operational safety.

[0004] Existing technologies often use PVC or PVC / CPVC blends as the matrix material for porous pipes. However, PVC has limited toughness and heat resistance, while CPVC, although it can improve heat resistance, has high melt viscosity and a narrow processing window, which can easily lead to uneven plasticization and extrusion pressure fluctuations in complex porous molds. Meanwhile, conventional inorganic fillers have poor compatibility with resin systems, easily causing agglomeration and interfacial debonding, resulting in a decline in the material's mechanical properties. Furthermore, some liquid additives, such as epoxy resin, if added directly, can easily cause wall adhesion and uneven dispersion. In addition, existing porous pipes often rely on a single external vacuum molding method during the molding and shaping process, which is insufficient to provide effective support for the internal pore structure, resulting in insufficient pore stability. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a thirteen-hole plastic pipe for power communication protection and its preparation method, which realizes stable extrusion molding of a complex thin-walled thirteen-hole power communication protection pipe in a modified polyvinyl chloride system with high CPVC content, and at the same time improves the pore shape consistency, interfacial bonding strength and processing stability of the porous structure.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] In a first aspect, the present invention provides a thirteen-hole plastic pipe for power communication protection, wherein the plastic pipe is integrally extruded from a modified polyvinyl chloride composition through a thirteen-hole composite molding die;

[0008] The modified polyvinyl chloride composition comprises the following components in parts by weight: 60-80 parts of PVC resin, 20-40 parts of CPVC resin, 8-16 parts of MBS impact modifier, 4-10 parts of chlorinated polyethylene and / or chlorinated polypropylene, 0.8-2.5 parts of epoxy resin E51, 10-18 parts of silane-modified composite filler, 4-7 parts of calcium-zinc composite stabilizer, 3-7 parts of ACR processing aid, 0.8-1.8 parts of internal lubricant, 1.2-2.8 parts of external lubricant, and 0.3-0.8 parts of high-temperature lubrication modifier;

[0009] The silane-modified composite filler comprises ultrafine calcium carbonate and organically modified montmorillonite, and the epoxy resin E51 is loaded on the surface of the silane-modified composite filler.

[0010] Preferably, the chlorine content of the CPVC resin is 63%-69%, and the degree of polymerization of the PVC resin is 700-1300.

[0011] Preferably, the mass ratio of the ultrafine calcium carbonate to the organically modified montmorillonite is (4-10):1, and the organically modified montmorillonite is a quaternary ammonium salt intercalated modified montmorillonite, wherein the quaternary ammonium salt is selected from one or more of hexadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and dioctadecyldimethylammonium chloride.

[0012] Preferably, the mass ratio of the epoxy resin E51 to the silane-modified composite filler is (0.08-0.22):1.

[0013] Preferably, the silane-modified composite filler is a composite filler treated with a hydrolyzed silane treatment solution, wherein the hydrolyzed silane treatment solution is obtained by hydrolyzing a silane coupling agent in an ethanol-water mixed solution, wherein the volume ratio of ethanol to water is 70:30-95:5, the hydrolysis pH is 4.0-5.5, and the hydrolysis time is 20-60 min.

[0014] Preferably, the internal lubricant is selected from one or more of stearic acid, calcium stearate, zinc stearate, and oxidized polyethylene wax; the external lubricant is selected from one or more of polyethylene wax, paraffin wax, and ester wax; and the high-temperature lubrication modifier is selected from one or more of high-melting-point polyethylene wax, oxidized polyethylene wax, and composite ester wax.

[0015] Secondly, the present invention provides a method for preparing a thirteen-hole plastic pipe for power communication protection, comprising the following steps:

[0016] S1. Add the silane coupling agent to the ethanol-water mixed solution, adjust the pH to 4.0-5.5, and hydrolyze for 20-60 min to obtain the hydrolyzed silane treatment solution;

[0017] S2. Add ultrafine calcium carbonate and organic modified montmorillonite to a high-speed mixer and preheat and mix at 60-85℃; spray the hydrolyzed silane treatment solution onto the surface of the filler and continue mixing for 10-30 minutes; then heat to 100-120℃ under ventilation or micro-vacuum conditions to remove water and alcohol solvents to obtain silane modified composite filler.

[0018] S3. After preheating epoxy resin E51 to 45-70℃, add it to the silane-modified composite filler at 80-105℃ by dripping, fine stream addition or spraying, so that the epoxy resin E51 spreads and is adsorbed on the surface of the silane-modified composite filler. Continue mixing for 3-10 minutes to obtain epoxy-supported composite filler.

[0019] S4. Add PVC resin, CPVC resin, calcium-zinc composite stabilizer and ACR processing aid to a high-speed mixer for initial mixing; when the material temperature rises to 65-75℃, add MBS impact modifier, chlorinated polyethylene and / or chlorinated polypropylene and internal lubricant; when the material temperature rises to 80-90℃, add external lubricant and high-temperature lubrication regulator, and continue mixing;

[0020] S5. When the resin hot mixing temperature reaches 85-95℃, add the epoxy-supported composite filler and continue hot mixing to 115-130℃; then transfer the hot mixed material to a cold mixer to cool to 40-55℃ to obtain the extruded mixture.

[0021] S6. The extrusion mixture is added to a twin-screw extruder, melted and plasticized, and then fed into a thirteen-hole composite molding die for integral extrusion to form a thirteen-hole extruded preform;

[0022] S7. The thirteen-hole extruded preform is introduced into the composite shaping device, which applies a vacuum adsorption force to the outer wall of the thirteen-hole extruded preform and introduces dry compressed air into the thirteen through holes to form a micro-positive pressure support in each through hole.

[0023] S8. The 13-hole extruded preform that has undergone composite shaping is subjected to graded cooling, followed by traction, printing of product markings, length cutting and inspection to obtain 13-hole plastic pipes for power and communication protection.

[0024] Preferably, in step S2, when the filler temperature reaches 100-120℃ and the volatile content drops to ≤0.5%, heating is stopped and the process transitions to a cooling or heat preservation mixing stage.

[0025] Preferably, in step S6, the temperature of the twin-screw extruder is set as follows: zone 1 170-180℃, zone 2 180-190℃, zone 3 185-200℃, zone 4 190-205℃, and the die head and mold 195-210℃, and the screw speed is 10-25 r / min.

[0026] Preferably, in step S7, the vacuum applied to the outer wall of the thirteen-hole extruded preform is -0.03MPa to -0.07MPa, and the pressure of the dry compressed air introduced into the thirteen through holes is 0.005MPa to 0.030MPa.

[0027] In step S8, the staged cooling includes first using warm water at 35-55℃ for slow cooling, and then using water at 15-30℃ for cooling, with a traction speed of 0.4-2.0m / min.

[0028] The beneficial effects of this invention are:

[0029] 1. This invention constructs a high-performance matrix system by compounding PVC resin and CPVC resin, which significantly improves heat resistance and thermal deformation stability while ensuring the basic rigidity of the material; by introducing MBS impact-resistant agent and chlorinated polyethylene and / or chlorinated polypropylene, the toughness and low-temperature impact resistance of the system are improved, enabling the material to meet the long-term service requirements of power communication protection pipes in complex environments, and achieving a synergistic balance of rigidity, toughness and heat resistance.

[0030] 2. This invention improves the interfacial compatibility between inorganic fillers and the resin matrix through a silane-modified composite filler system. Ultrafine calcium carbonate provides particle reinforcement, while organically modified montmorillonite provides lamellar reinforcement; the two work synergistically to enhance the system's mechanical support capacity. Simultaneously, by pretreating epoxy resin E51 and loading it onto the surface of the silane-modified composite filler, it enters the resin system in a uniformly dispersed state, avoiding problems such as wall adhesion, agglomeration, and localized enrichment caused by direct addition. This significantly improves the dispersion uniformity and interfacial bonding strength of the material system.

[0031] 3. This invention utilizes a composite lubrication system consisting of an internal lubricant, an external lubricant, and a high-temperature lubrication regulator to effectively reduce internal friction and mold wall friction in high-CPVC content systems during high-temperature extrusion, thereby reducing melt fracture, pressure fluctuations, and flow channel viscosity. Combined with a segmented hot mixing process, each functional component is added sequentially according to the temperature gradient, improving plasticization uniformity and melt flow stability, thus ensuring the continuous and stable molding of the complex thirteen-hole structure during the extrusion process.

[0032] 4. This invention utilizes a combined internal and external pressure differential shaping method, integrating external vacuum sizing with micro-positive pressure support within the thirteen through-holes, to effectively prevent collapse, out-of-roundness, and rib misalignment during the cooling process of the thirteen-hole structure. Furthermore, a staged cooling process reduces the shrinkage difference between the inner and outer layers, improving hole consistency and dimensional stability. The resulting thirteen-hole plastic conduit for power and communication protection possesses advantages such as stable hole shape, excellent compressive strength, low threading resistance, and strong construction adaptability, meeting the needs of multi-channel zoned laying of power and communication cables. Attached Figure Description

[0033] Figure 1 This is a longitudinal cross-sectional schematic diagram of the present invention.

[0034] The symbols for the main components are explained below:

[0035] Outer tube 1, middle tube 2, inner tube 3, first connecting block 4, second connecting block 5, first through hole 6, second through hole 7, positioning mark 8. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] like Figure 1 As shown, the thirteen-hole plastic pipe for power and communication protection described in this invention has multiple independent through holes, which can be used for the partitioned installation of power cables, communication optical cables, control cables, or backup cables. This structure is a multi-hole thin-walled integral extrusion structure with numerous internal cavities, ribs, and complex melt flow channels. Therefore, it places high demands on the material's melt strength, flow stability, interfacial bonding performance, and pore shape retention ability during the shaping process. The main improvement of this invention does not lie in simply changing the number of holes or the structural shape, but in improving the stable extrusion molding capability and finished product performance of the complex thirteen-hole structure through a specific modified polyvinyl chloride composition and composite preparation process.

[0038] The raw materials used in the following examples can be commercially available products. To ensure the effectiveness of the implementation, the following raw material specifications are preferred:

[0039] The PVC resin used is SG-5 type PVC resin with a degree of polymerization of 700-1300; the chlorine content of the CPVC resin is 63%-69%; the MBS impact agent is a core-shell structure MBS impact agent; chlorinated polyethylene and / or chlorinated polypropylene are used as toughness-modifying components; the epoxy value of epoxy resin E51 is 0.48-0.54 eq / 100g; the particle size D50 of ultrafine calcium carbonate is 3-5μm; the organic modified montmorillonite is quaternary ammonium salt intercalated modified montmorillonite, wherein the quaternary ammonium salt is selected from one or more of hexadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and dioctadecyldimethylammonium chloride; the silane coupling agent can be KH-550, KH-570, or a combination of both; the calcium-zinc composite stabilizer, ACR processing aid, internal lubricant, external lubricant, and high-temperature lubrication regulator can all be commonly used grades in the PVC / CPVC extrusion processing field.

[0040] The internal lubricant can be selected from one or more of stearic acid, calcium stearate, zinc stearate, and oxidized polyethylene wax; the external lubricant can be selected from one or more of polyethylene wax, paraffin wax, and ester wax; and the high-temperature lubrication regulator can be selected from one or more of high-melting-point polyethylene wax, oxidized polyethylene wax, and composite ester wax.

[0041] Example 1

[0042] Weigh the following components by weight:

[0043] 70 parts PVC resin, 30 parts CPVC resin, 12 parts MBS impact modifier, 7 parts chlorinated polyethylene and / or chlorinated polypropylene, 1.5 parts epoxy resin E51, 14 parts silane-modified composite filler, 5 parts calcium-zinc composite stabilizer, 5 parts ACR processing aid, 1.2 parts internal lubricant, 2.0 parts external lubricant, and 0.5 parts high-temperature lubrication regulator.

[0044] The silane-modified composite filler includes ultrafine calcium carbonate and organically modified montmorillonite, with a mass ratio of 7:1; the mass ratio of epoxy resin E51 to silane-modified composite filler is approximately 0.107:1, which falls within the range of (0.08-0.22):1.

[0045] S1. Add ethanol and deionized water to a reaction vessel at a volume ratio of 80:20, and add silane coupling agent KH-550 under stirring. Adjust the pH of the system to 4.5 with glacial acetic acid, and stir and hydrolyze at 35-45℃ for 45 min to obtain a hydrolyzed silane treatment solution.

[0046] The purpose of this step is to hydrolyze the silane coupling agent first to form silanol groups that can interact with the hydroxyl groups on the surface of the inorganic filler, thereby improving the subsequent surface modification effect of the filler.

[0047] S2. Add ultrafine calcium carbonate and organic modified montmorillonite to a high-speed mixer at a mass ratio of 7:1, preheat and mix at 60℃ for 5 minutes to initially disperse the two fillers.

[0048] Subsequently, the above-mentioned hydrolyzed silane treatment solution was added to the filler system by atomized spraying and mixed for another 15 minutes to ensure that the hydrolyzed silane treatment solution was evenly distributed on the surface of ultrafine calcium carbonate and organic modified montmorillonite.

[0049] After spraying, the temperature of the high-speed mixer is raised to 110℃, and moisture and alcohol solvents are removed under ventilation or micro-vacuum conditions for 20 minutes. Once the volatile content of the filler drops to ≤0.5%, heating is stopped and the mixture is switched to a heat preservation mixing or cooling state to obtain the silane-modified composite filler.

[0050] During this process, the temperature is controlled to reach 100-120℃ and then not kept at high temperature for a long time, so as to reduce the excessive self-condensation of silane coupling agent and ensure its effective modification of the filler surface.

[0051] S3. Preheat epoxy resin E51 to 60°C to reduce its viscosity, making it suitable for dropwise or fine-flow addition. Maintain the above silane-modified composite filler at approximately 100°C, and slowly add the preheated epoxy resin E51 dropwise under high-speed mixing conditions, controlling the addition time to 6-8 minutes. After the dropwise addition is complete, continue mixing for 8 minutes to allow the epoxy resin E51 to spread and be adsorbed on the surface of the hot filler, obtaining the epoxy-supported composite filler.

[0052] By first loading epoxy resin E51 onto the surface of silane-modified composite filler, it is possible to avoid the adhesion, clumping, or local enrichment caused by its high viscosity when it is directly added to the PVC / CPVC resin system. At the same time, it allows the filler to enter the resin system with the composite filler, which is beneficial to improving the interfacial bonding between the filler and the resin matrix.

[0053] S4. Add PVC resin, CPVC resin, calcium-zinc composite stabilizer, and ACR processing aid to a high-speed mixer for initial mixing. During initial mixing, ensure that the stabilizer and ACR processing aid preferentially come into full contact with the PVC resin and CPVC resin.

[0054] When the material temperature rises to 65-75℃, add MBS impact modifier, chlorinated polyethylene and / or chlorinated polypropylene and internal lubricant, and continue mixing to disperse the impact modifier and toughness modifier in the resin system.

[0055] When the material temperature rises to 80-90℃, add the external lubricant and high-temperature lubrication regulator, and continue mixing. By adding the lubrication system in stages, the external lubricant can be prevented from prematurely covering the surface of the resin particles, thus affecting the dispersion of stabilizers, ACR processing aids, and impact-resistant components. At the same time, it can improve the flow stability of the subsequent high-CPVC system in complex molds.

[0056] S5. When the resin hot mixing temperature reaches about 90°C, add the aforementioned epoxy-supported composite filler, continue hot mixing to 120°C, and maintain mixing for 10 minutes to ensure that the epoxy-supported composite filler is evenly distributed in the PVC / CPVC resin system.

[0057] After hot mixing, the hot-mixed material is transferred to a cold mixer to be cooled to 45°C to obtain an extruded mixture.

[0058] S6. The extrusion mixture is added to a twin-screw extruder, melted and plasticized, and then fed into a thirteen-hole composite molding die for integral extrusion to form a thirteen-hole extruded preform.

[0059] In this embodiment, the twin-screw extruder uses the following temperature settings:

[0060] Zone 1: 175℃, Zone 2: 185℃, Zone 3: 195℃, Zone 4: 200℃, Head and Mold: 205℃; Screw speed: 18r / min.

[0061] This temperature setting takes into account both the plasticization requirements of CPVC resin and the thermal stability of the PVC system, avoiding insufficient plasticization due to excessively low temperatures, and avoiding excessively high temperatures that could lead to resin thermal decomposition or abnormally high melt viscosity.

[0062] S7. The thirteen-hole extruded preform is introduced into the composite shaping device. The composite shaping device applies a vacuum adsorption force to the outer wall of the thirteen-hole extruded preform, and at the same time, dry compressed air is introduced into the thirteen through holes to form a micro-positive pressure support in each through hole.

[0063] In this embodiment, the vacuum degree of the outer wall is -0.05MPa, and the pressure of the dry compressed air introduced into the thirteen through holes is 0.02MPa.

[0064] External vacuum is used to control the outer diameter and outer wall roundness, while internal micro-positive pressure is used to support the central through hole, the first through hole, and the second through hole. The two work together to reduce the occurrence of hole collapse, out-of-roundness, and rib displacement in porous thin-walled structures during the shaping stage.

[0065] S8. After composite shaping, the 13-hole extruded preform is first placed in a 50℃ warm water bath for slow cooling for 2 minutes, and then placed in a 20℃ cold water bath for cooling for 3-5 minutes. After traction, printing of product labels, fixed-length cutting and inspection, 13-hole plastic pipes for power and communication protection are obtained.

[0066] In this embodiment, the traction speed is 1.2 m / min.

[0067] Staged cooling can reduce the cooling shrinkage difference between the outer wall, the inner hole wall and the ribs, and reduce the misalignment of the inner ribs and the distortion of the hole shape.

[0068] Example 2

[0069] 60 parts PVC resin, 20 parts CPVC resin, 8 parts MBS impact modifier, 4 parts chlorinated polyethylene and / or chlorinated polypropylene, 0.8 parts epoxy resin E51, 10 parts silane-modified composite filler, 4 parts calcium-zinc composite stabilizer, 3 parts ACR processing aid, 0.8 parts internal lubricant, 1.2 parts external lubricant, and 0.3 parts high-temperature lubrication regulator.

[0070] In the silane-modified composite filler, the mass ratio of ultrafine calcium carbonate to organically modified montmorillonite is 4:1; the mass ratio of epoxy resin E51 to silane-modified composite filler is 0.08:1.

[0071] The process parameters are as follows: die head and mold temperature 195℃, screw speed 10r / min, outer wall vacuum degree -0.03MPa, dry compressed air pressure in the thirteen through holes 0.005MPa, warm water slow cooling temperature 35℃, room temperature water cooling temperature 15℃, and traction speed 0.4m / min. The remaining preparation steps are the same as in Example 1.

[0072] Example 3

[0073] 80 parts PVC resin, 40 parts CPVC resin, 16 parts MBS impact modifier, 10 parts chlorinated polyethylene and / or chlorinated polypropylene, 2.5 parts epoxy resin E51, 18 parts silane-modified composite filler, 7 parts calcium-zinc composite stabilizer, 7 parts ACR processing aid, 1.8 parts internal lubricant, 2.8 parts external lubricant, and 0.8 parts high-temperature lubrication regulator.

[0074] In the silane-modified composite filler, the mass ratio of ultrafine calcium carbonate to organically modified montmorillonite is 10:1; the mass ratio of epoxy resin E51 to silane-modified composite filler is approximately 0.139:1.

[0075] The process parameters are as follows: die head and mold temperature 210℃, screw speed 25r / min, outer wall vacuum degree -0.07MPa, dry compressed air pressure in the thirteen through holes 0.030MPa, warm water slow cooling temperature 55℃, room temperature water cooling temperature 30℃, and traction speed 2.0m / min. The remaining preparation steps are the same as in Example 1.

[0076] Comparative Example 1

[0077] This comparative example uses a standard 13-hole PVC pipe formulation, without adding CPVC resin, epoxy resin E51, silane-modified composite filler, or the composite lubrication system of this invention. The remaining extrusion molding methods are the same as in Example 1.

[0078] Comparative Example 2

[0079] This comparative example is basically the same as Example 1, except that CPVC resin is not added, and PVC resin is used as the main resin. The remaining components and processes are kept as consistent as possible with Example 1.

[0080] Comparative Example 3

[0081] This comparative example is basically the same as Example 1, except that epoxy resin E51 is not pre-loaded on the surface of the silane-modified composite filler, but is directly added to the PVC / CPVC system during the resin hot mixing process. The remaining components and process parameters are the same as in Example 1.

[0082] Comparative Example 4

[0083] This comparative example is basically the same as Example 1, except that the ultrafine calcium carbonate and organically modified montmorillonite are added directly to the system as composite fillers without undergoing hydrolysis silane treatment. The remaining components and process parameters are the same as in Example 1.

[0084] Comparative Example 5

[0085] This comparative example is basically the same as Example 1, except that during the shaping process, only the outer wall of the thirteen-hole extruded preform is subjected to vacuum adsorption force, and dry compressed air is not introduced into the thirteen through holes. The remaining components and process parameters are the same as in Example 1.

[0086] Comparative Example 6

[0087] This comparative example is basically the same as Example 1, except that the amount of internal lubricant, external lubricant, and high-temperature lubrication regulator is reduced by about 40% overall. The remaining components and process parameters are the same as in Example 1.

[0088] The performance of the pipes obtained in Examples 1-3 and Comparative Examples 1-6 was tested using the following methods.

[0089] 1. Ring stiffness test

[0090] Ring stiffness was tested according to GB / T 9647, with a specimen length of 300 mm and a compression loading rate of 12.5 mm / min. The load on the pipe under specified deformation conditions was recorded, and the ring stiffness was calculated in kN / m².

[0091] 2. Low-temperature impact performance test

[0092] Low-temperature impact performance was tested according to GB / T 14152. After placing the samples at -5℃ for 1 hour, a drop hammer impact test was performed, and the presence of cracks, fractures, and pore wall damage was recorded. For ease of comparison, the impact resistance of different samples is expressed as impact strength in J / m.

[0093] 3. Hole shape deviation rate test

[0094] The cross-section of the pipe was measured using the slicing method or industrial CT scan. The actual diameters of the thirteen through holes were measured and compared with the corresponding design diameters. The hole shape deviation rate was calculated using the following formula:

[0095] Hole deviation rate = |Measured hole diameter - Designed hole diameter| / Designed hole diameter × 100%.

[0096] The average value of the thirteen perforation deviation rates is taken as the perforation deviation rate of the sample.

[0097] 4. Reinforcement offset test

[0098] Samples were taken at different lengths of the pipe, and images of the cross-sections were acquired. The offset distance between the actual center line and the design center line of the reinforcing bar was measured, and the average value of multiple points was taken as the reinforcing bar offset, in mm.

[0099] 5. Extrusion pressure fluctuation test

[0100] A pressure sensor is installed at the extruder die head to record the pressure fluctuations during continuous extrusion. The difference between the maximum and minimum pressures during the stable extrusion phase is taken as the extrusion pressure fluctuation value, expressed in MPa.

[0101] 6. Collapse Rate Test

[0102] For 100m of pipe produced continuously, the length showing obvious cavity collapse, out-of-roundness of the hole wall, or local deformation of the through hole is inspected. The collapse rate is calculated using the following formula:

[0103] Hole collapse rate = length of collapsed or out-of-round hole / total inspection length × 100%.

[0104] The test results of Examples 1-3 and Comparative Examples 1-6 are shown in Table 1.

[0105]

[0106] As shown in the table above, Example 1, as the preferred embodiment, achieves a ring stiffness of 12.8 kN / m², an impact strength of 780 J / m, a die shape deviation rate of only 2.1%, a rib offset of 0.18 mm, an extrusion pressure fluctuation of 0.05 MPa, and a die collapse rate of 0. This demonstrates that the present invention, through the synergistic effect of the modified polyvinyl chloride composition and the composite molding process, can achieve stable extrusion molding of a complex thirteen-hole structure and obtain good mechanical properties and die shape stability.

[0107] Example 2, using the lower limit formulation and process parameters, exhibited lower ring stiffness, impact strength, and die stability than Example 1, but still superior to the ordinary PVC system and several comparative examples. This demonstrates that the present invention remains feasible even under conditions of lower CPVC content, lower composite filler content, lower E51 dosage, and lower internal pressure support. Example 3, using the upper limit formulation and process parameters, achieved a ring stiffness of 13.0 kN / m², a die deviation rate of 2.6%, and a die collapse rate of 1%. This indicates that even with higher CPVC and filler content, good extrusion stability and die retention can still be maintained by enhancing the lubrication system and improving internal pressure support.

[0108] Comparative Example 1 uses a common PVC system, whose ring stiffness and impact strength are significantly lower than those of Example 1, and its hole shape deviation rate and hole collapse rate are higher, indicating that the common PVC system is difficult to meet the comprehensive requirements of rigidity, toughness and forming stability of the thirteen-hole complex thin-walled pipe.

[0109] Comparative Example 2, which did not contain CPVC resin, showed a decrease in ring stiffness and pore stability compared to Example 1, indicating that CPVC resin has a positive effect on improving heat resistance, heat distortion stability, and the molding stability of porous structures.

[0110] In Comparative Example 3, epoxy resin E51 was directly added to the resin system without being loaded onto the surface of the silane-modified composite filler. Its pore shape deviation rate and extrusion pressure fluctuation were higher than in Example 1. This indicates that direct addition of E51 easily leads to localized enrichment or uneven dispersion, thus affecting melt flow stability and pore shape consistency. In contrast, this invention pre-loads E51 onto the surface of the silane-modified composite filler, allowing it to be uniformly dispersed in the resin system along with the filler, which helps reduce localized wall adhesion, agglomeration, and interface defects.

[0111] Comparative Example 4 uses composite fillers without silane treatment. Its ring stiffness, impact strength, and pore stability are all lower than those of Example 1. This indicates that silane modification can improve the interfacial bonding between ultrafine calcium carbonate, organic modified montmorillonite, and PVC / CPVC matrix, reduce filler agglomeration and interfacial debonding, thereby improving the mechanical properties and molding stability of the material.

[0112] Comparative Example 5 only used external vacuum shaping without providing internal micro-positive pressure support for the thirteen through holes. Its hole collapse rate reached 15%, and the rib offset reached 1.10 mm, which was significantly higher than that of Example 1. This shows that for a thirteen-hole multi-cavity thin-walled structure, relying solely on external vacuum shaping is insufficient to effectively support the internal hole shape. The present invention, through the combination of external wall vacuum adsorption and internal micro-positive pressure support, can simultaneously control the outer diameter and internal hole shape during the shaping process, effectively reducing hole collapse and rib offset.

[0113] In Comparative Example 6, reducing the amount of lubrication system resulted in increased extrusion pressure fluctuations up to 0.22 MPa, and both the die deviation rate and the collapse rate increased. These results indicate that, under conditions of high CPVC content and a complex 13-hole die, the composite lubrication system formed by internal lubricant, external lubricant, and high-temperature lubrication modifier plays a crucial role in reducing melt friction, minimizing wall viscosity, stabilizing extrusion pressure, and preventing rib breakage.

[0114] In summary, this invention achieves stable extrusion molding of thirteen-hole power communication protection plastic pipes in a high-CPVC system through the synergistic effects of PVC / CPVC composite matrix, MBS and chlorinated polyethylene and / or chlorinated polypropylene toughening modification system, silane modified composite filler, E51 load dispersion method, composite lubrication system, segmented hot mixing, internal and external pressure difference composite shaping and graded cooling. This improves the pipe's ring stiffness, impact resistance, hole pattern consistency, rib stability and processing reliability.

[0115] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, appropriate adjustments or equivalent substitutions can be made to the types of raw materials, component ratios, process parameters, and equipment types without departing from the technical concept of the present invention, and all such adjustments or substitutions should be included within the protection scope of the present invention.

Claims

1. A thirteen-hole plastic pipe for power communication protection, characterized in that, The plastic pipe is integrally extruded from a modified polyvinyl chloride composition using a thirteen-hole composite molding die; The modified polyvinyl chloride composition comprises the following components in parts by weight: 60-80 parts of PVC resin, 20-40 parts of CPVC resin, 8-16 parts of MBS impact modifier, 4-10 parts of chlorinated polyethylene and / or chlorinated polypropylene, 0.8-2.5 parts of epoxy resin E51, 10-18 parts of silane-modified composite filler, 4-7 parts of calcium-zinc composite stabilizer, 3-7 parts of ACR processing aid, 0.8-1.8 parts of internal lubricant, 1.2-2.8 parts of external lubricant, and 0.3-0.8 parts of high-temperature lubrication modifier; The silane-modified composite filler comprises ultrafine calcium carbonate and organically modified montmorillonite, and the epoxy resin E51 is loaded on the surface of the silane-modified composite filler.

2. The thirteen-hole power communication protection plastic pipe according to claim 1, characterized in that, The CPVC resin has a chlorine content of 63%-69% and the PVC resin has a degree of polymerization of 700-1300.

3. The thirteen-hole plastic pipe for power communication protection according to claim 1, characterized in that, The mass ratio of the ultrafine calcium carbonate to the organically modified montmorillonite is (4-10):

1. The organically modified montmorillonite is a quaternary ammonium salt intercalated modified montmorillonite, and the quaternary ammonium salt is selected from one or more of hexadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and dioctadecyldimethylammonium chloride.

4. The thirteen-hole power communication protection plastic pipe according to claim 1, characterized in that, The mass ratio of the epoxy resin E51 to the silane-modified composite filler is (0.08-0.22):

1.

5. A thirteen-hole plastic pipe for power communication protection according to claim 1, characterized in that, The silane-modified composite filler is a composite filler treated with a hydrolyzed silane treatment solution. The hydrolyzed silane treatment solution is obtained by hydrolyzing a silane coupling agent in an ethanol-water mixed solution. The volume ratio of ethanol to water is 70:30-95:5, the hydrolysis pH is 4.0-5.5, and the hydrolysis time is 20-60 min.

6. A thirteen-hole plastic pipe for power communication protection according to claim 1, characterized in that, The internal lubricant is selected from one or more of stearic acid, calcium stearate, zinc stearate, and oxidized polyethylene wax; the external lubricant is selected from one or more of polyethylene wax, paraffin wax, and ester wax; and the high-temperature lubrication modifier is selected from one or more of high-melting-point polyethylene wax, oxidized polyethylene wax, and composite ester wax.

7. A method for preparing a thirteen-hole power communication protection plastic pipe as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Add the silane coupling agent to the ethanol-water mixed solution, adjust the pH to 4.0-5.5, and hydrolyze for 20-60 min to obtain the hydrolyzed silane treatment solution; S2. Add ultrafine calcium carbonate and organic modified montmorillonite to a high-speed mixer and preheat and mix at 60-85℃; spray the hydrolyzed silane treatment solution onto the surface of the filler and continue mixing for 10-30 minutes; then heat to 100-120℃ under ventilation or micro-vacuum conditions to remove water and alcohol solvents to obtain silane modified composite filler. S3. After preheating epoxy resin E51 to 45-70℃, add it to the silane-modified composite filler at 80-105℃ by dripping, fine stream addition or spraying, so that the epoxy resin E51 spreads and is adsorbed on the surface of the silane-modified composite filler. Continue mixing for 3-10 minutes to obtain epoxy-supported composite filler. S4. Add PVC resin, CPVC resin, calcium-zinc composite stabilizer and ACR processing aid to a high-speed mixer for initial mixing; when the material temperature rises to 65-75℃, add MBS impact modifier, chlorinated polyethylene and / or chlorinated polypropylene and internal lubricant; when the material temperature rises to 80-90℃, add external lubricant and high-temperature lubrication regulator, and continue mixing; S5. When the resin hot mixing temperature reaches 85-95℃, add the epoxy-supported composite filler and continue hot mixing to 115-130℃; then transfer the hot mixed material to a cold mixer to cool to 40-55℃ to obtain the extruded mixture. S6. The extrusion mixture is added to a twin-screw extruder, melted and plasticized, and then fed into a thirteen-hole composite molding die for integral extrusion to form a thirteen-hole extruded preform; S7. The thirteen-hole extruded preform is introduced into the composite shaping device, which applies a vacuum adsorption force to the outer wall of the thirteen-hole extruded preform and introduces dry compressed air into the thirteen through holes to form a micro-positive pressure support in each through hole. S8. The 13-hole extruded preform that has undergone composite shaping is subjected to graded cooling, followed by traction, printing of product markings, length cutting and inspection to obtain 13-hole plastic pipes for power and communication protection.

8. The method for preparing a thirteen-hole power communication protection plastic pipe according to claim 7, characterized in that, In step S2, when the filler temperature reaches 100-120℃ and the volatile content drops to ≤0.5%, heating is stopped and the process transitions to a cooling or heat preservation mixing stage.

9. The method for preparing a thirteen-hole power communication protection plastic pipe according to claim 7, characterized in that, In step S6, the temperature of the twin-screw extruder is set as follows: Zone 1 170-180℃, Zone 2 180-190℃, Zone 3 185-200℃, Zone 4 190-205℃, and the die head and mold 195-210℃, and the screw speed is 10-25 r / min.

10. The method for preparing a thirteen-hole power communication protection plastic pipe according to claim 7, characterized in that, In step S7, the vacuum applied to the outer wall of the thirteen-hole extruded preform is -0.03MPa to -0.07MPa, and the pressure of the dry compressed air introduced into the thirteen through holes is 0.005MPa to 0.030MPa. In step S8, the staged cooling includes first using warm water at 35-55℃ for slow cooling, and then using water at 15-30℃ for cooling, with a traction speed of 0.4-2.0m / min.

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