Cable protection pipe and preparation method thereof

Abstract

The invention provides a cable protection tube which is prepared by compounding cable protection tube resin and a glass fiber material, and the cable protection tube resin comprises the following components in parts by weight: 100 parts of low-viscosity resin, 5-10 parts of calcium carbonate, 1.0-1.5 parts of an internal release agent, 3-5 parts of a flame retardant, 2.0-3.0 parts of a curing agent, 0.5-1.0 part of white carbon black and 0.5-1.0 part of PE wax powder. The composite material has the advantages of small shrinkage, few pores, flame retardance and low price, and also has relatively good mechanical properties, resin stability and durability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable production, in particular to a cable protection pipe and a preparation method thereof. BACKGROUND

[0002] The cable protection pipe is a protective pipe wrapped outside the cable, and its core function is to protect the cable from mechanical damage, chemical corrosion and external interference, while enhancing insulation and prolonging service life. The cable protection pipe is widely used in the underground or open laying of power and communication fields, and is convenient for maintenance, which is the key to ensuring the safety and smoothness of the line.

[0003] Most of the existing cable protection pipes are produced by pultrusion process, and the cable protection pipe resin uses high-viscosity resin as the main raw material, and glass fibers are added to composite with the cable protection pipe resin to enhance the strength of the cable protection pipe. However, high-viscosity resin has high viscosity and poor flame retardant performance, and has high shrinkage rate during curing, which easily produces a large number of pores, seriously affecting the infiltration effect of glass fibers, resulting in insufficient fiber glue and reduced product density. At the same time, high-viscosity resin not only has a high price, but also uses a glue pouring process in the production of cable protection pipes, which further aggravates the problem of fiber infiltration, ultimately resulting in rough surface, poor flame retardant performance and insufficient mechanical strength of the cable protection pipe, which not only affects the product quality, but also limits the production capacity and increases the production cost. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a cable protection pipe.

[0005] The cable protection pipe disclosed in the present application comprises: a composite of cable protection pipe resin and glass fiber material, wherein the cable protection pipe resin comprises the following components by weight fraction: 100 parts of low-viscosity resin, 5-10 parts of calcium carbonate, 1.0-1.5 parts of internal release agent, 3-5 parts of flame retardant, 2.0-3.0 parts of curing agent, 0.5-1.0 parts of white carbon black, and 0.5-1.0 parts of PE wax powder.

[0006] Preferably, the curing agent comprises the following components by weight fraction: 1.0-1.5 parts of BPO and 1.0-1.5 parts of TBPB.

[0007] Preferably, the BPO comprises the following components by weight fraction: 49-52 parts of dibenzoyl peroxide, 20-25 parts of diisobutyl phthalate, and 15-25 parts of water.

[0008] Preferably, the TBPB comprises the following components by weight fraction: 69-71 parts of butyl peroxybenzoate, 19-21 parts of dimethyl phthalate, and 10 parts of di-tert-butyl peroxide.

[0009] Preferably, the mesh size of calcium carbonate is 400-800 mesh.

[0010] Preferably, the low-viscosity resin comprises the following components by weight: 65 parts polyester resin and 35 parts styrene.

[0011] Preferably, the glass fiber material is glass fiber yarn or glass fiber mat.

[0012] This application also discloses a method for preparing a cable protection pipe, comprising the following steps: adding low-viscosity resin, internal release agent, flame retardant, curing agent, fumed silica and PE wax powder, and stirring evenly; adding calcium carbonate and stirring evenly to obtain cable protection pipe resin; impregnating glass fiber material into the cable protection pipe resin to obtain prepreg; heating and curing the prepreg to form a shape; and obtaining a cable protection pipe.

[0013] Preferably, the prepreg heating and curing process involves sequential heating and curing in three zones, with the first zone having a temperature of 80-90℃, the second zone a temperature of 160-175℃, and the third zone a temperature of 180-185℃.

[0014] Preferably, during the step of impregnating the glass fiber material into the cable protection tube resin, a pneumatic diaphragm metering pump is used to circulate and replenish the cable protection tube resin.

[0015] The beneficial effects of this application are as follows: The cable protection pipe resin in this application uses low-viscosity resin as the main component. Compared with traditional high-viscosity resin, low-viscosity resin has the advantages of less shrinkage, fewer pores, flame retardancy, and low price. Simultaneously, calcium carbonate, as a filler, is an active powder that can adjust the viscosity of the cable protection pipe resin, further reducing its viscosity and thus weakening the shrinkage of the cable protection pipe product. This avoids pores and cracks caused by shrinkage, improves product performance, and promotes increased product density and strength. Flame retardants can improve the flame retardancy index of the cable protection pipe. Silica, through its thixotropic effect, optimizes the resin rheological behavior, improving the mechanical properties, resin stability, and durability of the cable protection pipe product. Furthermore, the combined use of PE wax powder and internal release agent can further enhance the internal release effect. By forming an isolation film on the surface, it ensures that the cable protection pipe product can be smoothly and continuously extracted from the high-temperature mold without damage, ensuring the stability and efficiency of the production process. It also improves the appearance quality of the cable protection pipe product and enhances the resin wetting effect and the filler's anti-settling effect, further improving the product's performance and strength. Detailed Implementation

[0016] Several embodiments of this application will be disclosed below. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit this application. That is, in some embodiments of this application, these practical details are not essential.

[0017] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit this application. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0018] To further understand the content, features, and effects of this application, the following embodiments are provided and detailed below.

[0019] Example 1: The cable protection pipe in this embodiment is made of cable protection pipe resin and glass fiber material. The cable protection pipe resin includes the following components by weight: 100 parts of low viscosity resin, 5-10 parts of calcium carbonate, 1.0-1.5 parts of internal release agent, 3-5 parts of flame retardant, 2.0-3.0 parts of curing agent, 0.5-1.0 parts of fumed silica, and 0.5-1.0 parts of PE wax powder.

[0020] In this embodiment, the cable protection pipe resin uses low-viscosity resin as the main component. Compared with traditional high-viscosity resin, low-viscosity resin has advantages such as less shrinkage, fewer pores, flame retardancy, and lower price. Meanwhile, calcium carbonate, as a filler, is an active powder that can adjust the viscosity of the cable protection pipe resin, further reducing its viscosity. This weakens the shrinkage of the cable protection pipe product, preventing pores and cracks caused by shrinkage, improving product performance, and increasing product density and strength. Flame retardants enhance the flame retardancy index of the cable protection pipe. Silica, through its thixotropic effect, optimizes the resin rheological behavior, improving the mechanical properties, resin stability, and durability of the cable protection pipe product. Furthermore, the combined use of PE wax powder and internal release agent further enhances the internal release effect. By forming an isolation film on the surface, it ensures the cable protection pipe product can be smoothly and continuously ejected from the high-temperature mold without damage, guaranteeing the stability and efficiency of the production process. It also improves the appearance quality of the cable protection pipe product, enhances the resin wetting effect and the filler's anti-settling effect, further improving the product's performance and strength.

[0021] Preferably, the curing agent comprises the following components by weight: 1.0-1.5 parts BPO and 1.0-1.5 parts TBPB. It is understood that BPO, as a medium-temperature curing agent, can decompose at 80-100 degrees Celsius to generate free radical-triggered resin, which reacts with the free radicals of crosslinking monomers to form a three-dimensional network structure. This ensures rapid curing of the resin within the mold and slower decomposition at room temperature, thus extending the resin's working time, facilitating fiber impregnation and process continuity. Simultaneously, effective curing ensures a tight bond between the resin and glass fiber, improving the product's strength and stiffness, reducing resin shrinkage, decreasing internal stress, and improving the dimensional stability of the cable protection conduit. TBPB, as a high-temperature curing agent with a decomposition temperature range of 140-160 degrees Celsius, is a high-temperature free radical initiator suitable for high-temperature, thick-walled, or high-traction-speed processes. By delaying the curing initiation point, it maintains stability in the preheating zone at the front of the mold, preventing premature resin gelation, ensuring full wetting of glass fibers, and rapidly decomposing and initiating curing in the high-temperature zone, thereby improving production efficiency. This also results in more uniform curing at high temperatures, reducing cracking or shrinkage problems caused by concentrated heat release inside thick-walled products. In other words, the curing agent in this embodiment uses a combination of medium-temperature and high-temperature curing agents, giving the cable protection pipe resin advantages such as low cost, strong practicality, high strength, high temperature resistance, and flame retardancy, making it widely applicable in the pultrusion process of cable protection pipes. Specifically, BPO comprises the following components by weight: 49-52 parts benzoyl peroxide, 20-25 parts diisobutyl phthalate, and 15-25 parts water. TBPB comprises the following components by weight: 69-71 parts butyl peroxide, 19-21 parts dimethyl phthalate, and 10 parts di-tert-butyl peroxide.

[0022] Preferably, the calcium carbonate has a mesh size of 400-800 mesh. It is understood that calcium carbonate in this mesh range has a suitable specific surface area, effectively avoiding the drawback of a sharp increase in resin viscosity due to excessively fine powder. This allows the system viscosity to be adjusted and stabilized within a low viscosity range suitable for the impregnation process. This ensures that the resin maintains excellent flowability, achieving rapid and thorough impregnation of the glass fiber and avoiding defects such as white streaks. Simultaneously, it also achieves a better bulk density, significantly improving the compactness of the cured composite material, thereby greatly reducing resin curing shrinkage, effectively suppressing the generation of internal pores and surface microcracks, and ultimately improving the strength, rigidity, and surface smoothness of the cable protection pipe product.

[0023] Preferably, the low-viscosity resin comprises the following components by weight: 65 parts polyester resin and 35 parts styrene. In specific applications, the low-viscosity resin serves as the matrix of the cable protection pipe resin, ensuring complete impregnation of the glass fibers. The primary purpose of selecting a low-viscosity resin is to meet the stringent requirements of the pultrusion process for resin flowability. In other words, low viscosity ensures that the resin can quickly and thoroughly penetrate and encapsulate each glass fiber during the curing and molding process, expelling air and thus preventing defects such as dry spots and white streaks in the product, thereby improving the mechanical properties of the cable protection pipe. Specifically, styrene, as an active diluent, primarily functions to significantly reduce the initial viscosity of the unsaturated polyester resin, adjusting it to a suitable impregnation process window. Furthermore, styrene is not an inert solvent; during curing, it undergoes a copolymerization reaction with the unsaturated double bonds in the polyester resin molecular chain, becoming an indispensable component of the three-dimensional cross-linked network structure. The 65 parts polyester resin and 35 parts styrene ratio ensures the lowest possible process viscosity within this system, while also providing sufficient styrene for complete participation in the curing reaction. This avoids increased shrinkage due to styrene volatilization from excessive styrene, or insufficient crosslinking of the polyester resin due to insufficient styrene, thus balancing excellent processing fluidity with the integrity of the network structure, mechanical strength, and dimensional stability of the final cured product. Specifically, the glass fiber material is either glass fiber yarn or glass fiber mat.

[0024] Example 2: The method for preparing the cable protection pipe in this embodiment includes the following steps: S1: Use a pneumatic diaphragm pump to pump the low-viscosity resin into the mixing tank. In specific applications, polyester resin and styrene are mixed in a certain proportion to obtain a low-viscosity resin, and then a pneumatic diaphragm pump is used to pump the low-viscosity resin into the mixing tank.

[0025] S2: Add the internal release agent, flame retardant, curing agent, fumed silica and PE wax powder to the low viscosity resin and stir thoroughly until uniform.

[0026] S3: Add calcium carbonate and stir for 5-10 minutes until the mixture is homogeneous to obtain cable protection pipe resin.

[0027] S4: Impregnate the fiberglass material with cable protection tube resin to obtain a prepreg. In specific applications, the cable protection tube resin is transported to the impregnation tank by a material transport vehicle to be compounded with the fiberglass material. That is, the impregnation tank contains cable protection tube resin, and the fiberglass material is impregnated through the cable protection tube resin in the impregnation tank to ensure that the fiberglass material is evenly coated with the cable protection tube resin, thus obtaining the prepreg. The prepreg is the fiberglass material that has been evenly coated with cable protection tube resin.

[0028] Preferably, in step S4, a pneumatic diaphragm metering pump is used to circulate and replenish the cable protection tube resin. In specific applications, the pneumatic diaphragm pump is used to circulate and draw the cable protection tube resin from the impregnation tank, that is, to draw the resin from the bottom of the tank. The pump then transports the extracted resin through pipelines and evenly sprays it back into the tank from a spray nozzle or spray pipe installed above it. This is equivalent to a secondary stirring of the prepared resin, increasing the wetting effect and improving product performance. Specifically, because the density of fillers such as calcium carbonate and silica in the cable protection tube resin is greater than that of low-viscosity resin, they will naturally settle in the static impregnation tank. The pneumatic diaphragm pump ensures that the resin is in a uniform state, guaranteeing the stability of product quality. Furthermore, the resin for cable protection tubes in the impregnation tank is fed using an automatic timed and quantitative feeding device. This means that the resin can be fed continuously during the impregnation process, and the viscosity and product quality of the cable protection tube resin will not be affected by the changes in the cyclic coating. This avoids the situation where the resin for cable protection tubes remains still for too long during the production process and cannot be used in time. This also avoids problems such as incompatibility between low viscosity resin and filler and filler sedimentation, which greatly improves product quality and output.

[0029] S5: Heating and curing the prepreg. In specific applications, the prepreg is pulled through a curing and molding device, which has three heating zones, each with independent temperature control. The prepreg passes through zone one, zone two, and zone three in sequence. The temperature of zone one is 80-90℃, the temperature of zone two is 160-175℃, and the temperature of zone three is 180-185℃. The pulling speed is 0.6~0.85m per minute.

[0030] S6: Obtain cable protection pipe.

[0031] Example 1: The preparation process of the cable protection tube in this embodiment is as follows: S1: Mix 65 parts of polyester resin and 35 parts of styrene to obtain a low-viscosity resin, and pump the low-viscosity resin into a mixing tank using a pneumatic diaphragm pump.

[0032] S2: Add 1.0 part of internal release agent, 3 parts of flame retardant, 1.0 part of BPO, 1.0 part of TBPB, 0.5 parts of fumed silica and 0.5 parts of PE wax powder to the low viscosity resin and stir thoroughly until uniform.

[0033] S3: Add 5 parts of calcium carbonate and stir for 5-10 minutes until the mixture is homogeneous to obtain cable protection pipe resin.

[0034] S4: Impregnate the fiberglass material in the cable protection tube resin to obtain a prepreg. In specific applications, the mass ratio of cable protection tube resin to fiberglass material is 23:77.

[0035] S5: The prepreg is pulled through the curing and molding equipment and then passed through three heating zones in sequence: zone one, zone two, and zone three for curing and molding. The temperature of zone one is 80℃, the temperature of zone two is 160℃, and the temperature of zone three is 180℃. The pulling speed is 0.85m per minute.

[0036] S6: Obtain cable protection pipe.

[0037] Example 2: The preparation process of the cable protection tube in this embodiment is as follows: S1: Mix 65 parts of polyester resin and 35 parts of styrene to obtain a low-viscosity resin, and pump the low-viscosity resin into a mixing tank using a pneumatic diaphragm pump.

[0038] S2: Add 1.2 parts of internal release agent, 3 parts of flame retardant, 1.2 parts of BPO, 1.2 parts of TBPB, 0.7 parts of fumed silica and 0.7 parts of PE wax powder to the low viscosity resin and stir thoroughly until uniform.

[0039] S3: Add 8 parts of calcium carbonate and stir for 5-10 minutes until the mixture is homogeneous to obtain cable protection pipe resin.

[0040] S4: Impregnate the fiberglass material in the cable protection tube resin to obtain a prepreg. In specific applications, the mass ratio of cable protection tube resin to fiberglass material is 23:77.

[0041] S5: The prepreg is pulled through the curing and molding equipment and then passed through three heating zones in sequence: zone one, zone two, and zone three for curing and molding. The temperature of zone one is 85℃, the temperature of zone two is 165℃, and the temperature of zone three is 185℃. The pulling speed is 0.7m per minute.

[0042] S6: Obtain cable protection pipe.

[0043] Example 3: The preparation process of the cable protection tube in this embodiment is as follows: S1: Mix 65 parts of polyester resin and 35 parts of styrene to obtain a low-viscosity resin, and pump the low-viscosity resin into a mixing tank using a pneumatic diaphragm pump.

[0044] S2: Add 1.5 parts of internal release agent, 5 parts of flame retardant, 1.5 parts of BPO, 1.5 parts of TBPB, 1.0 part of fumed silica and 1.0 part of PE wax powder to the low viscosity resin and stir thoroughly until uniform.

[0045] S3: Add 10 parts of calcium carbonate and stir for 5-10 minutes until the mixture is homogeneous to obtain cable protection pipe resin.

[0046] S4: Impregnate the fiberglass material in the cable protection tube resin to obtain a prepreg. In specific applications, the mass ratio of cable protection tube resin to fiberglass material is 23:77.

[0047] S5: The prepreg is pulled through the curing and molding equipment and then passed through three heating zones in sequence: zone one, zone two, and zone three for curing and molding. The temperature of zone one is 90℃, the temperature of zone two is 170℃, and the temperature of zone three is 180℃. The pulling speed is 0.65m per minute.

[0048] S6: Obtain cable protection pipe.

[0049] Example 4: The preparation process of the cable protection tube in this embodiment is as follows: S1: Mix 65 parts of polyester resin and 35 parts of styrene to obtain a low-viscosity resin, and pump the low-viscosity resin into a mixing tank using a pneumatic diaphragm pump.

[0050] S2: Add 1.5 parts of internal release agent, 5 parts of flame retardant, 1.5 parts of BPO, 1.5 parts of TBPB, 1.0 part of fumed silica and 1.0 part of PE wax powder to the low viscosity resin and stir thoroughly until uniform.

[0051] S3: Add 10 parts of calcium carbonate and stir for 5-10 minutes until the mixture is homogeneous to obtain cable protection pipe resin.

[0052] S4: Impregnate the fiberglass material in the cable protection tube resin to obtain a prepreg. In specific applications, the mass ratio of cable protection tube resin to fiberglass material is 23:77.

[0053] S5: The prepreg is pulled through the curing and molding equipment and then passed through three heating zones in sequence: zone one, zone two, and zone three for curing and molding. The temperature of zone one is 90℃, the temperature of zone two is 175℃, and the temperature of zone three is 185℃. The pulling speed is 0.6m per minute.

[0054] S6: Obtain cable protection pipe.

[0055] Specifically, the cable protection pipes in Examples 1-4 were subjected to performance tests according to the DL / T802.2-2017 standard for conduits for power cables. The performance tests included ring stiffness, circumferential tensile strength, Barcol hardness, and oxygen index tests. The test results are shown in the table below:

[0056] As shown in the table above, the ring stiffness of the cable protection pipes in Examples 1 to 4 is 26-29 kPa, the circumferential tensile strength is 210-230 MPa, and the Barcol hardness is above 40, indicating that the cable protection pipes in Examples 1 to 4 have good mechanical properties and hardness. The oxygen index is above 28, indicating that the cable protection pipes have good flame retardant properties, providing an important guarantee for the safety of power lines.

[0057] In summary, the cable protection pipe resin in this embodiment uses low-viscosity resin as the main component. Compared with traditional high-viscosity resin, low-viscosity resin has advantages such as less shrinkage, fewer pores, flame retardancy, and lower price. Meanwhile, calcium carbonate, as a filler, is an active powder that can adjust the viscosity of the cable protection pipe resin, further reducing its viscosity. This weakens the shrinkage of the cable protection pipe product, avoids pores and cracks caused by shrinkage, improves product performance, and increases product density and strength. Flame retardants can improve the flame retardancy index of the cable protection pipe. Silica, through its thixotropic effect, optimizes the resin rheological behavior, improving the mechanical properties, resin stability, and durability of the cable protection pipe product. Furthermore, the combined use of PE wax powder and internal release agent further enhances the internal release effect. By forming an isolation film on the surface, it ensures that the cable protection pipe product can be smoothly and continuously ejected from the high-temperature mold without damage, guaranteeing the stability and efficiency of the production process. It also improves the appearance quality of the cable protection pipe product, enhances the resin wetting effect and the anti-settling effect of the filler, further improving the product's performance and strength.

[0058] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A cable protection pipe, characterized in that, It is made of cable protection pipe resin and glass fiber material composite, wherein the cable protection pipe resin includes the following components by weight: 100 parts of low viscosity resin, 5-10 parts of calcium carbonate, 1.0-1.5 parts of internal release agent, 3-5 parts of flame retardant, 2.0-3.0 parts of curing agent, 0.5-1.0 parts of fumed silica, and 0.5-1.0 parts of PE wax powder.

2. The cable protection pipe according to claim 1, characterized in that, The curing agent comprises the following components by weight: 1.0-1.5 parts BPO and 1.0-1.5 parts TBPB.

3. The cable protection pipe according to claim 2, characterized in that, BPO comprises the following components by weight: 49-52 parts benzoyl peroxide, 20-25 parts diisobutyl phthalate, and 15-25 parts water.

4. The cable protection pipe according to claim 2, characterized in that, TBPB comprises the following components by weight: 69-71 parts butyl peroxide, 19-21 parts dimethyl phthalate, and 10 parts di-tert-butyl peroxide.

5. The cable protection pipe according to claim 1, characterized in that, The calcium carbonate has a mesh size of 400-800.

6. The cable protection pipe according to claim 1, characterized in that, The low-viscosity resin comprises the following components by weight: 65 parts polyester resin and 35 parts styrene.

7. The cable protection pipe according to claim 1, characterized in that, The glass fiber material is glass fiber yarn or glass fiber mat.

8. A method for preparing a cable protection pipe as described in any one of claims 1-7, characterized in that, Includes the following steps: Add low-viscosity resin, internal release agent, flame retardant, curing agent, fumed silica and PE wax powder, and stir well; Add calcium carbonate and stir until homogeneous to obtain cable protection tube resin; Glass fiber material is impregnated in the resin of the cable protection tube to obtain a prepreg; The prepreg is heated and cured to form a mold; Obtain cable protection pipes.

9. The method for preparing the cable protection pipe according to claim 8, characterized in that, In the prepreg heating and curing molding step, the prepreg is heated and cured in three zones in sequence, with the temperature of zone one being 80-90℃, zone two being 160-175℃, and zone three being 180-185℃.

10. The method for preparing the cable protection pipe according to claim 8, characterized in that, During the step of impregnating the glass fiber material into the cable protection tube resin, a pneumatic diaphragm metering pump is used to circulate and replenish the cable protection tube resin.

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