A corrosion-resistant, flame-retardant, low-resistance wire tube and its preparation method

Abstract

The present invention relates to a corrosion-resistant, flame-retardant, low-resistance wire conduit, characterized in that the wire conduit comprises a galvanized steel pipe body and an organic inner coating and an organic outer coating respectively coated on the inner wall surface and the outer wall surface of the galvanized steel pipe body; the organic inner coating and the organic outer coating both comprise a base layer and a surface layer; the surface layer is composed of the following raw materials in parts by weight: 100 parts of polyurethane prepolymer, 5 to 15 parts of auxiliary agent, and 20 to 25 parts of functional additives. The corrosion-resistant, flame-retardant, low-resistance wire conduit of the present invention solves the problem that existing wire conduits cannot take into account the comprehensive performance of corrosion resistance, flame retardancy, low threading resistance, and high strength, thereby meeting the requirements for long-term use under harsh conditions. The present invention also discloses a method for preparing a corrosion-resistant, flame-retardant, low-resistance wire conduit.

Description

Technical Field

[0001] The present invention relates to the technical field of wire tubes, and in particular to a corrosion-resistant, flame-retardant, low-resistance wire tube and a preparation method thereof. Background Art

[0002] Conduit can be categorized by material, either hot-dip galvanized or plastic. These are widely used as conduit for protecting wires and cables. Hot-dip galvanized conduit is made from high-quality cold-rolled steel strip and formed in a single step through high-frequency welding. The result is uniform wall thickness, near-zero internal weld burrs, smooth, perfectly rounded welds, and smooth, burr-free ends. Furthermore, one or both sides of the inner and outer walls are often treated with hot-dip galvanizing for protection. Hot-dip galvanized conduit is widely used for both exposed and concealed installations.

[0003] Both hot-dip galvanized and plastic conduit have different advantages and disadvantages. Specifically, existing hot-dip galvanized conduit offers superior flame retardancy, higher strength, and lower threading resistance compared to plastic conduit. However, its corrosion resistance is neutral and requires protection from rain and acidic substances. Plastic conduit, on the other hand, offers excellent corrosion resistance, but cannot match the strength, flame retardancy, and threading resistance of hot-dip galvanized conduit. Therefore, using only hot-dip galvanized or plastic conduit cannot meet the requirements for long-term safe use of conduit under harsh conditions. Summary of the Invention

[0004] In view of the above shortcomings of the existing technology, the present invention provides a corrosion-resistant, flame-retardant, low-resistance wire tube to solve the problem that the existing wire tube cannot take into account the comprehensive performance of corrosion resistance, flame retardancy, low threading resistance and high strength.

[0005] In order to achieve the above objects, the technical solution adopted by the present invention is:

[0006] A corrosion-resistant, flame-retardant, low-resistance wire conduit, comprising a galvanized steel pipe body and an organic inner coating and an organic outer coating respectively coated on the inner and outer wall surfaces of the galvanized steel pipe body; the organic inner coating and the organic outer coating both comprise a base layer and a surface layer; the surface layer is composed of the following raw materials in parts by weight: 100 parts of a polyurethane prepolymer, 5 to 15 parts of an auxiliary agent, and 20 to 25 parts of a functional additive.

[0007] As a preferred technical solution, the bottom layer is at least one of epoxy resin, acrylic resin, and polyvinyl alcohol resin.

[0008] As a preferred technical solution, the functional additive is a composite material with ultrafine hollow microbeads as the core and fluorosilane-grafted adamantane chemically modified polyurethane resin as the shell.

[0009] As a preferred technical solution, the preparation method of the functional additive is as follows: first, ultrafine hollow microspheres are ultrasonically dispersed in a mixture of ethylene glycol and trimethoxysilyl adamantane diol, the temperature is raised to 80-85°C, a mixture of dibutyltin dilaurate, diisocyanate and ethyl acetate is added, and the reaction is carried out for 1-5 hours; N,N-dihydroxy (diisopropyl) aniline (HPA) is added for chain extension reaction; the reaction product and perfluorotrimethoxysilane are hydrolyzed in an aqueous sodium hydroxide solution; and finally, N,N-bis(2-chloroethyl)-N'-(3-hydroxypropyl) diaminophosphoric acid is added to react to obtain the functional additive. The functional additive of the present invention uses ultrafine hollow microspheres as the core, and a polyurethane resin shell layer is chemically modified by synthesizing fluorosilane-grafted adamantane on the surface of the ultrafine hollow microspheres in steps, making it easy to compound with the main polyurethane prepolymer to obtain a highly dense wire tube surface layer, further making the wire tube have the excellent properties of low threading resistance and wear resistance. Specifically, the present invention first reacts an excess of diisocyanate with ethylene glycol and trimethoxysilyladamantane diol under the catalysis of dibutyltin dilaurate, followed by a chain extension reaction with HPA to produce a polyurethane intermediate grafted with trimethoxysilyladamantane. This intermediate is then hydrolyzed with perfluorotrimethoxysilane in an aqueous sodium hydroxide solution to produce a chemically modified polyurethane resin grafted with fluorosilane-adamantane, resulting in an organic coating on the surface of the conduit with excellent corrosion resistance and flame retardancy. Furthermore, the final addition of N,N-bis(2-chloroethyl)-N'-(3-hydroxypropyl)phosphoric acid diamino acid can react with the isocyanate-reactive functional groups to further enhance the flame retardancy of the conduit surface material.

[0010] As a preferred technical solution, the ultrafine hollow microspheres are made of a silicon-aluminum composite material with a sphericity greater than 90% and a particle size of 0.05 to 10 μm. These ultrafine hollow microspheres offer excellent fluidity, low density, and ease of packing. They possess not only excellent strength and toughness, but also high hardness and excellent flame retardancy. Furthermore, the hollow sphere structure provides a certain degree of thermal insulation on the surface of the conduit, further satisfying the requirements for use in harsh environments such as extreme cold or high temperatures.

[0011] As a preferred technical solution, the trimethoxysilyladamantane diol is obtained by an addition reaction of 5-(vinyloxy)-1,3-adamantane diol and acryloxymethyltrimethoxysilane under the action of an initiator.

[0012] As a preferred technical solution, the diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate.

[0013] As a preferred technical solution, the perfluorotrimethoxysilane is 1H,1H,2H,2H-perfluorodecyltrimethoxysilane or tridecafluorooctyltrimethoxysilane.

[0014] As a preferred technical solution, the auxiliary agent is at least one of a drying agent, a leveling agent, a surfactant, and a defoaming agent.

[0015] Another aspect of the present invention is to provide a method for preparing the corrosion-resistant, flame-retardant, low-resistance conduit as described above, the method comprising the following steps:

[0016] S1: providing a steel pipe body, the outer surface of which is pickled and hot-dip galvanized to obtain a galvanized steel pipe body;

[0017] S2: coating at least one of epoxy resin, acrylic resin, and polyvinyl alcohol resin as a base material on the inner and outer wall surfaces of the galvanized steel pipe body obtained in step S1;

[0018] S3: Weigh 100 parts of polyurethane prepolymer, 5 to 15 parts of auxiliary agents and 20 to 25 parts of functional additives by weight, stir and mix them evenly, apply them on the inner wall surface and outer wall surface of the galvanized steel pipe body obtained in step S2, and obtain the corrosion-resistant, flame-retardant and low-resistance wire pipe after curing and drying.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The corrosion-resistant, flame-retardant, low-resistance wire conduit of the present application is composed of a galvanized steel pipe body and an organic coating coated on its surface; wherein, the surface layer is mainly composed of a polyurethane prepolymer. Through the addition of functional additives and the combination of the effect of auxiliary agents, the wire conduit not only has excellent mechanical properties such as high strength, but also has excellent performance in use such as corrosion resistance, flame retardancy, and low threading resistance; it can meet the requirements of long-term use under harsh conditions. DETAILED DESCRIPTION

[0021] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0022] Example 1

[0023] The corrosion-resistant, flame-retardant, low-resistance wire conduit of this embodiment comprises a galvanized steel pipe body and an organic inner coating and an organic outer coating respectively coated on the inner wall surface and the outer wall surface of the galvanized steel pipe body; the organic inner coating and the organic outer coating both comprise a base layer (epoxy resin) and a surface layer; the surface layer is composed of the following raw materials in parts by weight: 100 parts of polyurethane prepolymer, 5 parts of auxiliary agent and 20 parts of functional additives.

[0024] The polyurethane prepolymer is prepared by compounding 63% by mass of diphenylmethane diisocyanate, 33% by mass of polycaprolactone polyol, and 4% by mass of polycarbonate polyol. The specific preparation method is conventional in the art and will not be described in detail here.

[0025] The functional additive is a composite material with ultrafine hollow microspheres as the core and a fluorosilane-grafted adamantane chemically modified polyurethane resin as the shell. The specific preparation method is as follows: first, ultrafine hollow microspheres (50g) are ultrasonically dispersed in a mixture of ethylene glycol (2mol) and trimethoxysilyl adamantane diol (0.5mol), the temperature is raised to 80-85°C, a mixture of dibutyltin dilaurate (0.35g), toluene diisocyanate (6mol), and ethyl acetate (250mL) is added, and the mixture is reacted for 3h; N,N-dihydroxy(diisopropyl)aniline (3mol) is added for chain extension reaction; the reaction product and tridecafluorooctyltrimethoxysilane (0.5mol) are hydrolyzed in a 20% sodium hydroxide aqueous solution (300mL); and finally, N,N-bis(2-chloroethyl)-N'-(3-hydroxypropyl) diaminophosphoric acid (1.2mol) is added for reaction to obtain the functional additive. The ultrafine hollow microspheres are made of a silicon-aluminum composite microsphere material with a sphericity greater than 90% and a particle size of 0.05 to 10 μm. The trimethoxysilyl adamantane diol is obtained by the addition reaction of 5-(vinyloxy)-1,3-adamantane diol and acryloxymethyltrimethoxysilane in a molar ratio of 1:1.1 under the action of a catalytic amount of ammonium persulfate as an initiator.

[0026] The additives are composed of a drying agent (calcium cyclohexane), a leveling agent (polyether siloxane copolymer with the model number TEGO 450), a surfactant (polyethylene glycol octylphenyl ether), and a defoaming agent (foam-breaking polysiloxane solution with the model number BYK141) in a mass ratio of 5:3:2:3.

[0027] The preparation method of the corrosion-resistant, flame-retardant, low-resistance wire tube of this embodiment comprises the following steps:

[0028] S1: providing a steel pipe body, the outer surface of which is pickled and hot-dip galvanized to obtain a galvanized steel pipe body;

[0029] S2: coating the inner and outer wall surfaces of the galvanized steel pipe body obtained in step S1 with epoxy resin as a base material; the thickness of the base material is 500 nm;

[0030] S3: Weigh 100 parts of polyurethane prepolymer, 5 parts of auxiliary agent and 20 parts of functional additives by weight, stir and mix evenly, apply them on the inner wall surface and outer wall surface of the galvanized steel pipe body obtained in step S2, and after curing and drying, obtain the corrosion-resistant, flame-retardant and low-resistance wire pipe with a surface layer thickness of 1 mm.

[0031] Example 2

[0032] The corrosion-resistant, flame-retardant, low-resistance wire conduit of this embodiment comprises a galvanized steel pipe body and an organic inner coating and an organic outer coating respectively coated on the inner and outer wall surfaces of the galvanized steel pipe body; the organic inner coating and the organic outer coating both comprise a base layer (acrylic resin) and a surface layer; the surface layer is composed of the following raw materials in parts by weight: 100 parts

[0033] Polyurethane prepolymer, 10 parts of auxiliary agents and 22 parts of functional additives. The polyurethane prepolymer is the same as that in Example 1.

[0034] The functional additive is a composite material with ultrafine hollow microbeads as the core and fluorosilane-grafted adamantane chemically modified polyurethane resin as the shell. The specific preparation method is as follows: first, ultrafine hollow microspheres (50g) are ultrasonically dispersed in a mixed solution consisting of ethylene glycol (2mol) and trimethoxysilyladamantane diol (0.5mol), the temperature is raised to 80-85°C, a mixture consisting of dibutyltin dilaurate (0.35g), isophorone diisocyanate (6mol) and ethyl acetate (250mL) is added, and the mixture is reacted for 3h; N,N-dihydroxy(diisopropyl)aniline (3mol) is added for chain extension reaction; the reaction product and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (0.5mol) are hydrolyzed in a sodium hydroxide aqueous solution (300mL) with a mass concentration of 20%; and finally, N,N-bis(2-chloroethyl)-N'-(3-hydroxypropyl)phosphoric acid diamino (1.2mol) is added for reaction to obtain the functional additive. The ultrafine hollow microspheres are made of a silicon-aluminum composite microsphere material with a sphericity greater than 90% and a particle size of 0.05 to 10 μm. The trimethoxysilyl adamantane diol is obtained by the addition reaction of 5-(vinyloxy)-1,3-adamantane diol and acryloxymethyltrimethoxysilane in a molar ratio of 1:1.1 under the action of a catalytic amount of ammonium persulfate as an initiator.

[0035] The additives are composed of a drying agent (calcium cyclohexane), a leveling agent (polyether siloxane copolymer with the model number TEGO 450), a surfactant (polyethylene glycol octylphenyl ether), and a defoaming agent (foam-breaking polysiloxane solution with the model number BYK141) in a mass ratio of 5:3:2:3.

[0036] The preparation method of the corrosion-resistant, flame-retardant, low-resistance wire tube of this embodiment comprises the following steps:

[0037] S1: providing a steel pipe body, the outer surface of which is pickled and hot-dip galvanized to obtain a galvanized steel pipe body;

[0038] S2: coating the inner and outer wall surfaces of the galvanized steel pipe body obtained in step S1 with acrylic resin as a base material; the thickness of the base layer is 400 nm;

[0039] S3: Weigh 100 parts of polyurethane prepolymer, 10 parts of auxiliary agent and 22 parts of functional additives by weight, stir and mix evenly, apply them on the inner wall surface and outer wall surface of the galvanized steel pipe body obtained in step S2, and after curing and drying, obtain the corrosion-resistant, flame-retardant and low-resistance wire pipe with a surface layer thickness of 1.1 mm.

[0040] Example 3

[0041] This embodiment of the corrosion-resistant, flame-retardant, low-resistance conduit comprises a galvanized steel pipe body and an organic inner coating and an organic outer coating applied to the inner and outer surfaces of the galvanized steel pipe body, respectively. The organic inner coating and the organic outer coating each comprise a base layer (polyvinyl alcohol resin) and a surface layer. The surface layer is composed of the following raw materials in parts by weight: 100 parts polyurethane prepolymer, 15 parts auxiliary agent, and 25 parts functional additive. The polyurethane prepolymer is the same as in Example 1.

[0042] The functional additive is a composite material with ultrafine hollow microspheres as the core and a fluorosilane-grafted adamantane chemically modified polyurethane resin as the shell. The specific preparation method is as follows: first, ultrafine hollow microspheres (50g) are ultrasonically dispersed in a mixture of ethylene glycol (2mol) and trimethoxysilyl adamantane diol (0.5mol), the temperature is raised to 80-85°C, a mixture of dibutyltin dilaurate (0.35g), diphenylmethane diisocyanate (6mol), and ethyl acetate (250mL) is added, and the mixture is reacted for 3h; N,N-dihydroxy(diisopropyl)aniline (3mol) is added for chain extension reaction; the reaction product and tridecafluorooctyltrimethoxysilane (0.5mol) are hydrolyzed in a 20% sodium hydroxide aqueous solution (300mL); and finally, N,N-bis(2-chloroethyl)-N'-(3-hydroxypropyl) diaminophosphoric acid (1.2mol) is added for reaction to obtain the functional additive. The ultrafine hollow microspheres are made of a silicon-aluminum composite microsphere material with a sphericity greater than 90% and a particle size of 0.05 to 10 μm. The trimethoxysilyl adamantane diol is obtained by the addition reaction of 5-(vinyloxy)-1,3-adamantane diol and acryloxymethyltrimethoxysilane in a molar ratio of 1:1.1 under the action of a catalytic amount of ammonium persulfate as an initiator.

[0043] The additives are composed of a drying agent (calcium cyclohexane), a leveling agent (polyether siloxane copolymer with the model number TEGO 450), a surfactant (polyethylene glycol octylphenyl ether), and a defoaming agent (foam-breaking polysiloxane solution with the model number BYK141) in a mass ratio of 5:3:2:3.

[0044] The preparation method of the corrosion-resistant, flame-retardant, low-resistance wire tube of this embodiment comprises the following steps:

[0045] S1: providing a steel pipe body, the outer surface of which is pickled and hot-dip galvanized to obtain a galvanized steel pipe body;

[0046] S2: coating the inner and outer wall surfaces of the galvanized steel pipe body obtained in step S1 with a polyvinyl alcohol resin as a base material; the base layer has a thickness of 600 nm;

[0047] S3: Weigh 100 parts of polyurethane prepolymer, 15 parts of auxiliary agent and 25 parts of functional additives by weight, stir and mix evenly, apply them on the inner wall surface and outer wall surface of the galvanized steel pipe body obtained in step S2, and after curing and drying, obtain the corrosion-resistant, flame-retardant and low-resistance wire pipe with a surface layer thickness of 0.9 mm.

[0048] Comparative Example 1

[0049] The structure and preparation steps of the wire tube of this comparative example are basically the same as those of Example 1, except that, in the preparation method of the wire tube of this comparative example, no functional additives are added to the raw materials of the surface layer.

[0050] Comparative Example 2

[0051] The structure and preparation steps of the wire tube of this comparative example are basically the same as those of Example 1, except that in the preparation method of the wire tube of this comparative example, no ultrafine hollow microspheres are added during the preparation of the functional additive, and only fluorosilane-grafted adamantane chemically modified polyurethane resin is included.

[0052] Comparative Example 3

[0053] The structure and preparation steps of the wire tube of this comparative example are basically the same as those of Example 1, except that, in the preparation method of the wire tube of this comparative example, trimethoxysilyladamantane diol is not added during the preparation of the functional additive.

[0054] Comparative Example 4

[0055] The structure and preparation steps of the wire tube of this comparative example are basically the same as those of Example 1, except that, in the preparation method of the wire tube of this comparative example, tridecafluorooctyltrimethoxysilane is not added during the preparation of the functional additive.

[0056] The performance of the wire tubes prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested, and the performance results are shown in Table 1:

[0057] Compressive performance is tested according to IEC 61386-2017. Under the same load (1250N) and duration (30 minutes), the lower the deformation (%) of the conduit, the greater its compressive resistance.

[0058] Low-temperature impact performance is tested according to JG3050-1998. The more drop hammer impact tests that pass (i.e., the coating is not broken by the impact), the better the low-temperature impact performance of the conduit.

[0059] The surface friction coefficient is tested in accordance with GB / T10006-2021. The lower the surface friction coefficient, the lower the threading resistance of the conduit.

[0060] High temperature resistance After being placed in a constant temperature box at 120℃ for 24 hours, the surface friction coefficient test was carried out again.

[0061] The oxygen index is tested in accordance with GB / T2406.2-2009. The higher the oxygen index, the better the flame retardant performance of the conduit.

[0062] Salt spray resistance is tested according to ASTM D5894. The longer the salt spray resistance, the better the corrosion resistance of the conduit.

[0063] Table 1

[0064]

[0065] It can be seen that the present invention has considerable advantages over the currently used technologies. The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention claimed.

Claims

1. A corrosion-resistant, flame-retardant, low-resistance conduit, characterized in that: The conduit comprises a galvanized steel pipe body and an organic inner coating and an organic outer coating respectively coated on the inner and outer wall surfaces of the galvanized steel pipe body; the organic inner coating and the organic outer coating each comprise a base layer and a surface layer; the surface layer comprises the following raw materials in parts by weight: 100 parts of a polyurethane prepolymer, 5 to 15 parts of an auxiliary agent, and 20 to 25 parts of a functional additive; the functional additive is prepared by the following method: first, ultrafine hollow microspheres are ultrasonically dispersed in a mixed solution of ethylene glycol and trimethoxysilyl adamantane diol, the mixture is heated to 80-85°C, a mixture of dibutyltin dilaurate, diisocyanate, and ethyl acetate is added, and the mixture is reacted for 1 to 5 hours; N,N-dihydroxy(diisopropyl)aniline is added for chain extension reaction; the reaction product and perfluorotrimethoxysilane are hydrolyzed in a sodium hydroxide aqueous solution; and finally, N,N-bis(2-chloroethyl)-N'-(3-hydroxypropyl) diaminophosphoric acid is added for reaction to obtain the functional additive.

2. The corrosion-resistant, flame-retardant, low-resistance conduit according to claim 1, characterized in that: The bottom layer is at least one of epoxy resin, acrylic resin and polyvinyl alcohol resin.

3. The corrosion-resistant, flame-retardant, low-resistance conduit according to claim 1, characterized in that: The functional additive is a composite material with ultrafine hollow microbeads as the core and fluorosilane-grafted adamantane chemically modified polyurethane resin as the shell.

4. The corrosion-resistant, flame-retardant, low-resistance conduit according to claim 3, characterized in that: The ultrafine hollow microspheres are silicon-aluminum composite microspheres with a sphericity greater than 90% and a particle size of 0.05 to 10 μm.

5. The corrosion-resistant, flame-retardant, low-resistance conduit according to claim 1, characterized in that: The trimethoxysilyladamantane diol is obtained by the addition reaction of 5-(vinyloxy)-1,3-adamantane diol and acryloxymethyltrimethoxysilane under the action of an initiator.

6. The corrosion-resistant, flame-retardant, low-resistance conduit according to claim 1, characterized in that: The diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate.

7. The corrosion-resistant, flame-retardant, low-resistance conduit according to claim 1, characterized in that: The perfluorotrimethoxysilane is 1H,1H,2H,2H-perfluorodecyltrimethoxysilane or tridecafluorooctyltrimethoxysilane.

8. The corrosion-resistant, flame-retardant, low-resistance conduit according to claim 1, characterized in that: The auxiliary agent is at least one of a drying agent, a leveling agent, a surfactant, and a defoaming agent.

9. A method for preparing the corrosion-resistant, flame-retardant, low-resistance wire tube according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: S1: providing a steel pipe body, the outer surface of which is pickled and hot-dip galvanized to obtain a galvanized steel pipe body; S2: coating at least one of epoxy resin, acrylic resin, and polyvinyl alcohol resin as a base material on the inner and outer wall surfaces of the galvanized steel pipe body obtained in step S1; S3: Weigh 100 parts of polyurethane prepolymer, 5 to 15 parts of auxiliary agents and 20 to 25 parts of functional additives by weight, stir and mix them evenly, apply them on the inner wall surface and outer wall surface of the galvanized steel pipe body obtained in step S2, and obtain the corrosion-resistant, flame-retardant and low-resistance wire pipe after curing and drying.

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