High-toughness PVC electrical conduit and preparation method thereof

Abstract

The invention discloses a high-toughness PVC electrical conduit and a preparation method thereof. The electrical conduit is prepared from PVC resin, an ethylene-ethyl acrylate copolymer, nano aluminum oxide, a stabilizer, a flame retardant, an antioxidant, a lubricant and a pigment according to a certain ratio. The preparation method of the electrical conduit comprises the following steps: S1, uniformly mixing the PVC resin, the ethylene-ethyl acrylate copolymer, the nano aluminum oxide, the stabilizer, the flame retardant, the antioxidant, the lubricant and the pigment to obtain a mixed material; and S2, adding the mixed material into a double-screw extruder, and after extrusion molding is completed, cooling and shaping to obtain the high-toughness PVC electrical conduit. The electrical conduit has good mechanical property and flame retardant property, especially has good toughness, does not turn white during bending, and does not crack and wrinkle at low temperature.

Description

Technical Field

[0001] The invention relates to the technical field of power cable casings, and in particular to a high-toughness PVC electrical casing and a preparation method thereof. Background Art

[0002] PVC electrical conduit, commonly known as threading tube, is a white PVC wire tube that is corrosion-resistant, leak-proof, and used for threading wires. It can protect cables from damage and is suitable for high temperature, cold, dusty, vibrating, humid and other places. As a protective cover for wires and cables, PVC electrical conduit plays a vital role in modern power systems.

[0003] On the one hand, the electrical conduit needs to have a high structural strength, which requires it to have high compressive strength, rigidity and hardness, to ensure that the electrical conduit will not be flattened during use, especially when buried in concrete, and meet the use requirements. When pursuing a high structural strength of the electrical conduit, the toughness of the electrical conduit will inevitably be sacrificed, resulting in a decrease in the toughness of the electrical conduit. When the power conduit is in a low temperature environment, the toughness of the electrical conduit decreases, and it is easy to break brittlely, especially in places where stress is concentrated, cracks are more likely to occur.

[0004] On the other hand, during the construction process, the electrical conduit needs to be bent when it needs to pass through the wall, the ground or other obstacles. If the electrical conduit is not bent, it is necessary to use pipe fittings to make transition connections at the bends. The electrical conduit needs to be cut and connected with the pipe fittings many times, which is not only troublesome to operate and seriously affects the construction efficiency, but also easy to cause waste and increase the construction cost. However, the electrical conduit tends to turn white after being bent, which is caused by the poor toughness of the electrical conduit. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a high-toughness PVC electrical conduit and a preparation method thereof. The electrical conduit has good mechanical properties and flame retardant properties, especially good toughness, does not turn white when bent, and does not crack or wrinkle at low temperatures.

[0006] The technical solution adopted to achieve the above-mentioned purpose of the present invention is:

[0007] A high-toughness PVC electrical conduit is prepared from the following raw materials in parts by weight:

[0008] PVC resin 100 parts

[0009] 4-8 parts of ethylene-ethyl acrylate copolymer

[0010]

[0011] Furthermore, the stabilizer is a calcium-zinc composite stabilizer.

[0012] Furthermore, the flame retardant is an alkyl phosphate flame retardant.

[0013] Furthermore, the flame retardant is selected from at least one of trialkyl phosphate, trimethyl phosphate and triethyl phosphate.

[0014] Furthermore, the antioxidant is at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076.

[0015] Furthermore, the lubricant is at least one of calcium stearate, ethylene bis-12-hydroxystearamide, polyethylene wax and pentaerythritol stearate.

[0016] Furthermore, the pigment is at least one of titanium dioxide, pigment orange 13, ultramarine blue and carbon black.

[0017] A method for preparing a high-toughness PVC electrical casing comprises the following steps:

[0018] S1, uniformly mixing PVC resin, ethylene-ethyl acrylate copolymer, nano-alumina, stabilizer, flame retardant, antioxidant, lubricant and pigment to obtain a mixed material;

[0019] S2, adding the mixed material into a twin-screw extruder, and after extrusion molding, cooling and shaping are completed to obtain the high-toughness PVC electrical conduit.

[0020] Furthermore, the processing temperature of the twin-screw extruder barrel is 150-200°C, wherein the temperature of zone 1 is 170-180°C, the temperature of zone 2 is 180-190°C, the temperature of zone 3 is 175-185°C, the temperature of zone 4 is 170-180°C, and the temperature of zone 5 is 165-175°C.

[0021] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0022] 1. The present invention adopts the synergistic toughening of the elastomer ethylene-ethyl acrylate copolymer and the nano-particle nano-alumina, which significantly improves the toughness of the electrical casing. On the one hand, the electrical casing does not turn white when bent, and on the other hand, the electrical casing does not crack or wrinkle at low temperatures. At the same time, the nano-alumina has high resistivity and good insulation, so that the electrical casing has good electrical properties.

[0023] 2. The present invention uses alkyl phosphate flame retardants as flame retardants. Alkyl phosphate flame retardants have good low-temperature performance, will not affect the low-temperature toughness of the electrical conduit, and will also make the electrical conduit have good flame retardant properties. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to specific embodiments, but these embodiments are not to be interpreted as limiting the protection scope of the present invention in any sense.

[0025] Example 1

[0026] A high-toughness PVC electrical conduit, characterized in that it is prepared from the following raw materials in parts by weight:

[0027]

[0028] The preparation method of the above-mentioned high-toughness PVC electrical conduit is as follows:

[0029] 1. Add PVC resin, ethylene-ethyl acrylate copolymer, nano alumina, calcium zinc composite stabilizer, trialkyl phosphate, antioxidant 1010, antioxidant 168, polyethylene wax, pentaerythritol stearate and pigment orange 13 into a high mixing pot, mix well, cool and obtain a mixed material.

[0030] 2. The mixed material is conveyed to a twin-screw extruder, and the extruder current is set to 75A, the temperature of the barrel zone 1 is 175°C, the temperature of the zone 2 is 185°C, the temperature of the zone 3 is 180°C, the temperature of the zone 4 is 175°C, and the temperature of the zone 5 is 170°C. After the extrusion molding is completed, it is cooled and shaped to obtain the high-toughness PVC electrical conduit.

[0031] Example 2

[0032] A high-toughness PVC electrical conduit, characterized in that it is prepared from the following raw materials in parts by weight:

[0033]

[0034]

[0035] The preparation method of the high-toughness PVC electrical conduit in this embodiment is the same as that in Example 1.

[0036] Example 3

[0037] A high-toughness PVC electrical conduit, characterized in that it is prepared from the following raw materials in parts by weight:

[0038]

[0039] The preparation method of the high-toughness PVC electrical conduit in this embodiment is the same as that in Example 1.

[0040] Comparative Example 1

[0041] A PVC electrical conduit, characterized in that it is prepared from the following raw materials in parts by weight:

[0042]

[0043]

[0044] The preparation method of the PVC electrical conduit in this comparative example is the same as that in Example 1.

[0045] Comparative Example 2

[0046] A PVC electrical conduit, characterized in that it is prepared from the following raw materials in parts by weight:

[0047]

[0048] The preparation method of the PVC electrical conduit in this comparative example is the same as that in Example 1.

[0049] Comparative Example 3

[0050] A PVC electrical conduit, characterized in that it is prepared from the following raw materials in parts by weight:

[0051]

[0052]

[0053] The preparation method of the PVC electrical conduit in this comparative example is the same as that in Example 1.

[0054] The following tests were conducted on the PVC electrical conduits prepared in Examples 1-3 and Comparative Examples 1-3: 1. Whitening and empty folds at the bends; 2. Cracking and wrinkling at low temperatures; 3. Flame retardancy; 4. Insulation. The results are shown in the following table (taking 305-20 wire conduit as an example):

[0055]

Claims

1. A high-toughness PVC electrical conduit, characterized in that It is prepared from the following raw materials in parts by weight:

2. The high-toughness PVC electrical conduit according to claim 1, characterized in that: The stabilizer is a calcium-zinc composite stabilizer.

3. The high-toughness PVC electrical conduit according to claim 1, characterized in that: The flame retardant is an alkyl phosphate flame retardant.

4. The high-toughness PVC electrical conduit according to claim 3, characterized in that: The flame retardant is selected from at least one of trialkyl phosphate, trimethyl phosphate and triethyl phosphate.

5. The high-toughness PVC electrical conduit according to claim 1, characterized in that: The antioxidant is at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076.

6. The high-toughness PVC electrical conduit according to claim 1, characterized in that: The lubricant is at least one of calcium stearate, ethylene bis-12-hydroxystearamide, polyethylene wax and pentaerythritol stearate.

7. The high-toughness PVC electrical conduit according to claim 1, characterized in that: The pigment is at least one of titanium dioxide, pigment orange 13, ultramarine blue and carbon black.

8. A method for preparing the high-toughness PVC electrical conduit according to claim 1, characterized in that The steps include: S1, uniformly mixing PVC resin, ethylene-ethyl acrylate copolymer, nano-alumina, stabilizer, flame retardant, antioxidant, lubricant and pigment to obtain a mixed material; S2, adding the mixed material into a twin-screw extruder, and after extrusion molding, cooling and shaping are completed to obtain the high-toughness PVC electrical conduit.

9. The method for preparing the high-toughness PVC electrical casing according to claim 8, characterized in that: The processing temperature of the twin-screw extruder barrel is 150-200°C, wherein the temperature of zone 1 is 170-180°C, the temperature of zone 2 is 180-190°C, the temperature of zone 3 is 175-185°C, the temperature of zone 4 is 170-180°C, and the temperature of zone 5 is 165-175°C.

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