A high-toughness steel strand and its preparation method

Abstract

This invention relates to the field of power cable technology, and proposes a high-toughness steel strand and its preparation method. The high-toughness steel strand includes bare stranded wire and an epoxy coating sprayed onto the surface of the bare stranded wire. The epoxy coating raw materials include the following components in parts by weight: 100 parts epoxy resin, 25-30 parts carboxylated ternary chloroform resin, 20-50 parts polyphenylene ether, 30-40 parts nano-calcium carbonate, 2-4 parts curing agent, and 1-3 parts degassing agent. This technical solution solves the problem of poor toughness of epoxy coatings on steel strands in related technologies.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, specifically to a high-toughness steel strand and its preparation method. Background Technology

[0002] In the power industry, steel strand is commonly used as the ground wire in overhead transmission lines or as the reinforcing core of power cables. Its application is particularly important in overhead power lines, ensuring stable cable operation in harsh environments. Steel strand can be classified into galvanized steel strand, epoxy-coated steel strand, and aluminum-clad steel strand, among which epoxy-coated steel strand is more widely used. Currently, epoxy-coated steel strand suffers from poor toughness of the epoxy coating, which seriously affects its practical application. Therefore, there is an urgent need to develop a high-toughness epoxy-coated steel strand to improve the toughness of the epoxy coating. Summary of the Invention

[0003] This invention proposes a high-toughness steel strand and its preparation method, which solves the problem of poor toughness of epoxy coating on steel strands in related technologies.

[0004] The technical solution of the present invention is as follows:

[0005] This invention proposes a high-toughness steel strand, comprising bare strand and an epoxy coating sprayed on the surface of the bare strand. The epoxy coating comprises the following components by weight: 100 parts epoxy resin, 25-30 parts carboxylated ternary chloroform resin, 20-50 parts polyphenylene ether, 30-40 parts nano-calcium carbonate, 2-4 parts curing agent, and 1-3 parts degassing agent.

[0006] As a further technical solution, the weight ratio of the carboxyl ternary chloroacetic acid resin to polyphenylene ether is 1:1~1.5.

[0007] In this invention, when the weight ratio of carboxyl ternary chloroacetic acid resin to polyphenylene ether is 1:1 to 1.5, it is beneficial to further improve the toughness of the epoxy coating of steel strand.

[0008] As a further technical solution, the nano-calcium carbonate is modified nano-calcium carbonate, and the raw materials for the modified nano-calcium carbonate include nano-calcium carbonate, sodium dodecyl sulfonate, and o-cresolphthalein.

[0009] In this invention, nano-calcium carbonate was added to improve the toughness of the epoxy coating on steel strands. However, nano-calcium carbonate is prone to agglomeration, which affects the toughness improvement effect. The inventors discovered that modifying nano-calcium carbonate with sodium dodecyl sulfonate and o-cresolphthalein can, on the one hand, prevent the agglomeration of nano-calcium carbonate, and on the other hand, when cracks appear in the epoxy coating, the modified nano-calcium carbonate can enter the crack interior. The active substances on its surface can interact with the polymer chains, delaying the crack propagation, thereby further improving the toughness of the epoxy coating on steel strands.

[0010] As a further technical solution, the weight ratio of the nano-calcium carbonate, sodium dodecyl sulfonate, and o-cresolphthalein is 15:0.5:0.5~4.5.

[0011] In this invention, when the weight ratio of nano-calcium carbonate, sodium dodecyl sulfonate, and o-cresolphthalein is 15:0.5:0.5~4.5, it helps to further improve the toughness of the epoxy coating on the steel strand.

[0012] As a further technical solution, the modified nano-calcium carbonate is prepared by dissolving sodium dodecyl sulfonate and o-cresolphthalein in ethanol, adding nano-calcium carbonate, dispersing it evenly, and concentrating it to obtain modified nano-calcium carbonate.

[0013] As a further technical solution, the melting temperature is 50~60℃.

[0014] As a further technical solution, the particle size of the nano-calcium carbonate is 50~100nm.

[0015] As a further technical solution, the curing agent is one or more of dicyandiamide, 2-methylimidazole, and adipic acid dihydrazide.

[0016] As a further technical solution, the degassing agent is benzoin or micronized wax.

[0017] As a further technical solution, the number of strands in the bare stranded wire is 6 to 12.

[0018] As a further technical solution, the material of the bare stranded wire includes one of 50CrVA steel, 60Si2Mn steel, and 82MnA steel.

[0019] As a further technical solution, the thickness of the epoxy coating is 380~600μm.

[0020] The present invention also proposes a method for preparing the high-toughness steel strand, comprising the following steps:

[0021] S1. Extrude the raw material of the epoxy coating and granulate it to obtain epoxy coating masterbatch;

[0022] S2. The epoxy coating masterbatch is sprayed onto the surface of the bare stranded wire to obtain a high-toughness steel stranded wire.

[0023] As a further technical solution, in step S1, the temperature during extrusion is 170~190℃.

[0024] The working principle and beneficial effects of this invention are as follows:

[0025] In this invention, the raw materials for the high-toughness steel strand epoxy coating include epoxy resin, carboxyl ternary chloroform resin, and polyphenylene ether. The carboxyl ternary chloroform resin can open the epoxy groups of the epoxy resin, thereby facilitating the continuous interpenetration of polyphenylene ether to form a complex mesh structure, hindering crack propagation, and thus improving the toughness of the steel strand epoxy coating. Furthermore, the addition of nano-calcium carbonate can act as an inorganic rigid particle toughening agent, thereby improving the toughness of the steel strand epoxy coating. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] In the following examples and comparative examples, unless otherwise specified, the bare stranded wire has 6 strands, is made of 50CrVA steel, uses CYD-014 epoxy resin, uses TP-400M carboxylated ternary chloroform resin, uses PPO-E2114 polyphenylene ether, and has a particle size of 50nm for nano-calcium carbonate.

[0028] Example 1

[0029] A method for preparing high-toughness steel strand includes the following steps:

[0030] S1. By weight, 100 parts of epoxy resin, 25 parts of carboxylated ternary chloroform resin, 20 parts of polyphenylene ether, 30 parts of nano-calcium carbonate, 2 parts of dicyandiamide and 1 part of benzoin are blended, extruded and granulated to obtain epoxy coating masterbatch.

[0031] During extrusion, the temperature in zone one is 170℃, the temperature in zone two is 190℃, and the temperature in zone three is 180℃.

[0032] S2. Spray epoxy resin coating masterbatch onto the surface of bare stranded wire and dry it to obtain high-toughness steel stranded wire.

[0033] The epoxy coating has a thickness of 500 μm.

[0034] Example 2

[0035] A method for preparing high-toughness steel strand includes the following steps:

[0036] S1. By weight, 100 parts of epoxy resin, 30 parts of carboxylated ternary chloroform resin, 50 parts of polyphenylene ether, 40 parts of nano-calcium carbonate, 4 parts of dicyandiamide and 3 parts of benzoin are blended, extruded and granulated to obtain epoxy coating masterbatch.

[0037] During extrusion, the temperature in zone one is 170℃, the temperature in zone two is 190℃, and the temperature in zone three is 180℃.

[0038] S2. Spray epoxy resin coating masterbatch onto the surface of bare stranded wire and dry it to obtain high-toughness steel stranded wire.

[0039] The epoxy coating has a thickness of 500 μm.

[0040] Example 3

[0041] A method for preparing high-toughness steel strand includes the following steps:

[0042] S1. By weight, 100 parts of epoxy resin, 30 parts of carboxylated ternary chloroform resin, 20 parts of polyphenylene ether, 40 parts of nano-calcium carbonate, 4 parts of dicyandiamide and 3 parts of benzoin are blended, extruded and granulated to obtain epoxy coating masterbatch.

[0043] During extrusion, the temperature in zone one is 170℃, the temperature in zone two is 190℃, and the temperature in zone three is 180℃.

[0044] S2. Spray epoxy resin coating masterbatch onto the surface of bare stranded wire and dry it to obtain high-toughness steel stranded wire.

[0045] The epoxy coating has a thickness of 500 μm.

[0046] Example 4

[0047] A method for preparing high-toughness steel strand includes the following steps:

[0048] S1. By weight, 100 parts of epoxy resin, 30 parts of carboxylated ternary chloroform resin, 30 parts of polyphenylene ether, 40 parts of nano-calcium carbonate, 4 parts of dicyandiamide and 3 parts of benzoin are blended, extruded and granulated to obtain epoxy coating masterbatch.

[0049] During extrusion, the temperature in zone one is 170℃, the temperature in zone two is 190℃, and the temperature in zone three is 180℃.

[0050] S2. Spray epoxy resin coating masterbatch onto the surface of bare stranded wire and dry it to obtain high-toughness steel stranded wire.

[0051] The epoxy coating has a thickness of 500 μm.

[0052] Example 5

[0053] A method for preparing high-toughness steel strand includes the following steps:

[0054] S1. By weight, 100 parts of epoxy resin, 30 parts of carboxylated ternary chloroform resin, 45 parts of polyphenylene ether, 40 parts of nano-calcium carbonate, 4 parts of dicyandiamide and 3 parts of benzoin are blended, extruded and granulated to obtain epoxy coating masterbatch.

[0055] During extrusion, the temperature in zone one is 170℃, the temperature in zone two is 190℃, and the temperature in zone three is 180℃.

[0056] S2. Spray epoxy resin coating masterbatch onto the surface of bare stranded wire and dry it to obtain high-toughness steel stranded wire.

[0057] The epoxy coating has a thickness of 500 μm.

[0058] Example 6

[0059] The only difference between this embodiment and Example 5 is that in this embodiment, the nano-calcium carbonate is modified nano-calcium carbonate. The preparation method of modified nano-calcium carbonate is as follows: by weight, 2.5 parts of sodium dodecyl sulfonate are dissolved in ethanol at 55°C, 37.5 parts of nano-calcium carbonate are added, dispersed evenly, and concentrated to obtain modified nano-calcium carbonate.

[0060] Example 7

[0061] The only difference between this embodiment and Example 6 is that, in this embodiment, the modified nano-calcium carbonate is prepared by dissolving 2.5 parts by weight of o-cresolphthalein in ethanol at 55°C, adding 37.5 parts by weight of nano-calcium carbonate, dispersing evenly, and concentrating to obtain modified nano-calcium carbonate.

[0062] Example 8

[0063] The only difference between this embodiment and Example 6 is that, in this embodiment, the modified nano-calcium carbonate is prepared by dissolving 1.25 parts by weight of o-cresolphthalein and 1.25 parts by weight of sodium dodecyl sulfonate in ethanol at 55°C, adding 37.5 parts by weight of nano-calcium carbonate, dispersing evenly, and concentrating to obtain modified nano-calcium carbonate.

[0064] Example 9

[0065] The only difference between this embodiment and Embodiment 8 is that, in this embodiment, when preparing modified nano-calcium carbonate, the weight parts of o-cresolphthalein are 9 parts, the weight parts of sodium dodecyl sulfonate are 1 part, and the weight parts of nano-calcium carbonate are 30 parts.

[0066] Comparative Example 1

[0067] The only difference between this comparative example and Example 1 is that no carboxyl ternary chloroacetic acid resin was added in this comparative example.

[0068] Comparative Example 2

[0069] The only difference between this comparative example and Example 1 is that polyphenylene ether was not added in this comparative example.

[0070] Comparative Example 3

[0071] The only difference between this comparative example and Example 1 is that carboxyl ternary chloroprene resin and polyphenylene ether were not added in this comparative example.

[0072] Comparative Example 4

[0073] The only difference between this comparative example and Example 1 is that nano-calcium carbonate was not added in this comparative example.

[0074] The epoxy coating masterbatches prepared in Examples 1-9 and Comparative Examples 1-4 were extruded into sheets to obtain 120×15×10mm samples. The impact strength of each sample under unnotched conditions was measured using a JJ-20 memory impact testing machine. The high-toughness steel strands prepared in Examples 1-9 and Comparative Examples 1-4 were subjected to 10 drop hammer tests. The test height was 30cm, the drop weight was 1kg, and the Rockwell hardness was 55HRC. After 10 drop hammer tests, the test was considered passed if the epoxy coating of the steel strand remained intact and the strand was not exposed. The test results are shown in Table 1 below.

[0075] Table 1 Test Results

[0076]

[0077] A comparison of Example 1 and Comparative Examples 1-3 shows that the addition of carboxyl ternary chloroprene resin and polyphenylene ether to the epoxy coating raw materials can significantly improve the toughness of the epoxy coating on steel strands. A comparison of Example 1 and Comparative Example 4 shows that the addition of nano-calcium carbonate can significantly improve the toughness of the epoxy coating on steel strands.

[0078] A comparison of Examples 2-3 and Examples 4-5 shows that a weight ratio of carboxyl ternary vinyl acetate resin to polyphenylene ether of 1:1-1.5 is beneficial for further improving the toughness of the epoxy coating on steel strands. A comparison of Examples 5 and Examples 6-8 shows that modifying nano-calcium carbonate with sodium dodecyl sulfonate and o-cresolphthalein can further improve the toughness of the epoxy coating on steel strands.

[0079] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high ductility steel strand, characterized in that, The product includes bare stranded wire and an epoxy coating sprayed onto the surface of the bare stranded wire. The raw materials of the epoxy coating include the following components in parts by weight: 100 parts epoxy resin, 25-30 parts carboxylated ternary chloroform resin, 20-50 parts polyphenylene ether, 30-40 parts modified nano calcium carbonate, 2-4 parts curing agent, and 1-3 parts degassing agent. The weight ratio of the carboxyl ternary chloroacetic acid resin to polyphenylene ether is 1:1~1.5; the raw materials for the modified nano-calcium carbonate include nano-calcium carbonate, sodium dodecyl sulfonate, and o-cresolphthalein in a weight ratio of 15:0.5:0.5~4.5; the preparation method of the modified nano-calcium carbonate is as follows: dissolve sodium dodecyl sulfonate and o-cresolphthalein in ethanol, add nano-calcium carbonate, disperse evenly, concentrate, and obtain the modified nano-calcium carbonate.

2. The high-toughness steel strand according to claim 1, characterized in that, The dissolution process takes place at a temperature of 50-60°C.

3. The high-toughness steel strand according to claim 1, characterized in that, The curing agent is one or more of dicyandiamide, 2-methylimidazole, and adipic acid dihydrazide.

4. The high-toughness steel strand according to claim 1, characterized in that, The degassing agent is benzoin or micronized wax.

5. A method for preparing high-toughness steel strand as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Extrude the raw material of the epoxy coating and granulate it to obtain epoxy coating masterbatch; S2. The epoxy coating masterbatch is sprayed onto the surface of the bare stranded wire to obtain a high-toughness steel stranded wire.

6. The method for preparing a high-toughness steel strand according to claim 5, characterized in that, In step S1, the extrusion temperature is 170~190℃.

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