A honeycomb foaming double-layer insulation processing technology and a preparation method thereof

Abstract

The application belongs to the technical field of cable production, and particularly relates to a honeycomb foaming type double-layer insulation processing technology and a preparation method thereof, which comprises conductor preparation, placing the conductor in a honeycomb mold sleeve to make the conductor coaxial with the honeycomb mold sleeve; foaming insulation material mixing and melting, adding a certain amount of nucleating agent into polyethylene material, and the main component of the nucleating agent is azodicarbonamide; uniformly stirring the mixture of the polyethylene material and the nucleating agent; passing in foaming gas, passing the mixture into an extruder, and melting and extruding through the extruder while passing nitrogen into the extruder. The honeycomb foaming insulation utilizes the honeycomb structure to greatly improve the overall mechanical strength of the insulation sheath, and has high stability, so that only the double layer can achieve good use effect, the traditional three-layer co-extrusion method is changed, the production difficulty is reduced, and the use effect is good.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cable production, and particularly relates to a honeycomb foaming type double-layer insulation processing technology and a preparation method thereof. BACKGROUND

[0002] As a main transmission medium for transmitting information in a communication system, with the development of digital communication technology, the transmission frequency of the cable is higher and higher, and the transmission bandwidth is wider and wider, so the attenuation of the cable is required to be smaller, and the performance is required to be more stable, so the foaming insulation material is widely applied to the communication cable.

[0003] The foaming mode at present is generally divided into chemical foaming and physical foaming, the chemical foaming is to generate foam by adding a foaming agent, and the physical foaming is to form foam by injecting inert gas through a nucleating agent, and in order to expand the application field of the physical foaming and meet the needs of the production of digital communication cables, a physical foaming insulation co-extrusion technology is newly developed, that is, a three-layer structure composed of an inner skin layer, a foaming insulation layer and an outer skin layer, wherein the outer skin layer is only used to improve the mechanical strength and the aesthetic degree of the outer surface, but the thickness of the outer skin layer is usually about 50 mu, the increase of the mechanical strength is limited, and the use effect of the foaming insulation layer is affected, and the process of the three-layer co-extrusion is more complex, and the production difficulty is great.

[0004] Therefore, the honeycomb foaming type double-layer insulation processing technology and the preparation method thereof are provided to solve the above problems. SUMMARY

[0005] The application aims at the above problems, and provides a honeycomb foaming type double-layer insulation processing technology and a preparation method thereof.

[0006] In order to achieve the above purpose, the following technical scheme is adopted: a honeycomb foaming type double-layer insulation processing technology, comprising the following steps:

[0007] S1, conductor preparation;

[0008] S2, foaming insulation material mixing and melting;

[0009] S3, foaming gas is introduced;

[0010] S4, double-layer co-extrusion insulation material is coated on the conductor;

[0011] S5, cooling, drying and winding.

[0012] A use method of the honeycomb foaming type double-layer insulation processing technology, comprising the following steps:

[0013] a. the conductor is placed in the honeycomb mold sleeve, so that the conductor is coaxial with the honeycomb mold sleeve;

[0014] b. Add a certain amount of nucleating agent to the polyethylene material, and the main component of the nucleating agent is azobisamide. The mixture of the polyethylene material and the nucleating agent is uniformly stirred by mixing;

[0015] c. The mixture in step b is introduced into the extruder, and is melted and extruded by the extruder, while nitrogen is introduced into the extruder;

[0016] d. A double-layer co-extrusion "cross" die head is installed at the head of the extruder in step c, and the mixture is extruded and coated on the conductor and the honeycomb die sleeve in step a;

[0017] e. The extruded material in step d is cooled by a cold water tank, dried by a drying machine, and finally wound by a winding machine.

[0018] Preferably, the honeycomb die sleeve used in step a includes two semicircular die sleeves, and the side walls of the two semicircular die sleeves are integrally provided with a plurality of hollow protrusions, and the inner holes of the hollow protrusions are hexagonal.

[0019] Preferably, the outer sides of the two semicircular die sleeves are sleeved with semicircular blocking sleeves, and the two semicircular blocking sleeves are in contact with the end faces of the plurality of hollow protrusions on the same side.

[0020] Preferably, in step a, the conductor needs to be preheated before being placed in the honeycomb die sleeve, and the preheating temperature is set to be in the range of 100-150°C.

[0021] Preferably, the pressure of the nitrogen introduced in step c is kept above 200 bar.

[0022] Preferably, the film thickness of the inner layer of the foamed insulation extruded in step d is set to be in the range of 8-12 μm.

[0023] Compared with the existing technology, the honeycomb foamed double-layer insulation processing technology and its preparation method have the following advantages:

[0024] The foamed cable insulation sheath can be prepared by steps S1-S5, the honeycomb double-layer insulation cable sheath can be prepared by steps a-e, and the overall mechanical strength of the insulation sheath can be greatly improved by the honeycomb structure, and the stability is high, so that good use effect can be achieved by only double-layer, the traditional three-layer co-extrusion method is changed, the production difficulty is reduced, and the use effect is good. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 is a structure diagram of a honeycomb die sleeve of the honeycomb foamed double-layer insulation processing technology and its preparation method provided by the present application.

[0026] Fig. 2 Figure 1 is a schematic diagram of the shape structure of the hollow protrusion of the honeycomb mold sleeve provided by the honeycomb foaming double-layer insulation processing technology and the preparation method thereof.

[0027] In the figure: 1, semi-circular mold sleeve; 2, hollow protrusion; 3, semi-circular blocking sleeve. DETAILED DESCRIPTION

[0028] The following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[0029] As shown in Figure 1, a honeycomb foaming double-layer insulation processing technology comprises the following steps: Figs. 1-2

[0030] S1, conductor preparation;

[0031] S2, foaming insulation material mixing and melting;

[0032] S3, foaming gas is introduced;

[0033] S4, double-layer co-extrusion insulation material is coated on the conductor;

[0034] S5, cooling, drying and winding.

[0035] A method for using the honeycomb foaming double-layer insulation processing technology as described above comprises the following steps:

[0036] a. placing the conductor inside the honeycomb mold sleeve, so that the conductor is coaxial with the honeycomb mold sleeve;

[0037] b. adding a certain amount of nucleating agent to the polyethylene material, the main component of the nucleating agent being azodicarbonamide, and uniformly stirring the mixture of the polyethylene material and the nucleating agent;

[0038] c. introducing the mixture in step b into the extruder and melting and extruding it through the extruder, while introducing nitrogen into the extruder;

[0039] d. installing a double-layer co-extrusion "cross" head on the head of the extruder in step c, extruding the mixture through the head to coat it on the conductor and inside the honeycomb mold sleeve in step a, the extruder being an NMT60-30D type main extruder, and the head being a double-layer extruder head matched with the NMT60-30D type main extruder, the extruded inner layer film thickness being 10 μm, which can not only satisfy the advantage of stable inner layer connection, but also not excessively affect the conductor;

[0040] ​e. The extruded material in step d is cooled by a cold water tank, the cooling is carried out by combining spray cooling and cooling water tank, and is dried by a blowing machine, and finally the cable is wound by a winding machine.

[0041] The honeycomb die sleeve used in step a comprises two half-round die sleeves 1, the side walls of the two half-round die sleeves 1 are integrally provided with a plurality of hollow protrusions 2, and the inner holes of each hollow protrusion 2 are hexagonal. The extruded insulation material is extruded into the honeycomb die sleeve, the insulation material fills the inside of the hollow protrusion 2 and expands and foams, and a honeycomb-shaped micropore can be formed. The honeycomb structure has high mechanical strength, and the hollow protrusion 2 can increase the compression resistance of the cable surface.

[0042] The outer sides of the two half-round die sleeves 1 are sleeved with half-round blocking sleeves 3, and the two half-round blocking sleeves 3 are in contact with the end faces of the plurality of hollow protrusions 2 on the same side. The half-round blocking sleeve 3 can prevent the insulation material from being extruded too much, causing the formed honeycomb protrusions to be uneven, affecting the appearance of the cable surface.

[0043] In step a, the conductor needs to be preheated before being placed in the honeycomb die sleeve. The preheating temperature is set to be in the range of 100-150°C.

[0044] In step c, the pressure of the nitrogen gas is kept above 200 bar.

[0045] In step d, the film thickness of the extruded inner layer foamed insulation is set to be in the range of 8-12 μm.

[0046] The operation principle of the present application is described as follows: the conductor is placed in the honeycomb die sleeve, the conductor is coaxial with the honeycomb die sleeve, a certain amount of nucleating agent is added to the polyethylene material, and the mixture of the polyethylene material and the nucleating agent is uniformly stirred by mixing, then it is fed into the extruder, and nitrogen gas is fed into the extruder at the same time. The head of the extruder is a double-layer co-extrusion "cross" head. The mixture is extruded through the head and coated on the conductor and in the honeycomb die sleeve. The inner layer of insulation material wraps the surface of the conductor to form a thin inner layer. When the extruded insulation material is extruded into the honeycomb die sleeve, the insulation material fills the inside of the hollow protrusion 2 and expands and foams to form a honeycomb-shaped micropore. The honeycomb structure can improve the mechanical strength, and the hollow protrusion 2 can increase the compression resistance of the cable surface. After extrusion, the extruded material is cooled by a cold water tank, dried by a blowing machine, and finally wound by a winding machine.

[0047] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A process for manufacturing a honeycomb-foamed double-layer insulation, characterized by, It includes the following steps: a. The conductor is placed inside the honeycomb mold cover, and the conductor is coaxial with the honeycomb mold cover; b. Add a certain amount of nucleating agent to the polyethylene material, and the main component of the nucleating agent is azodicarbonamide, mix the polyethylene material and the nucleating agent, and stir evenly; c. The mixture in step b is passed into the extruder, and is melted and extruded through the extruder, while nitrogen is introduced into the extruder; d. The head of the extruder in step c is equipped with a double-layer co-extrusion "cross" head, and the mixture is extruded through the head to coat the conductor and the honeycomb mold cover in step a; e. The extruded material in step d is cooled in a cold water tank, dried by a drying machine, and finally wound by a winding machine. The honeycomb mold cover used in the a step includes two semicircular molds (1), and the side walls of the two semicircular molds (1) are integrally provided with a plurality of hollow protrusions (2), and the inner holes of each hollow protrusion (2) are hexagonal. The outer sides of the two semicircular molds (1) are provided with semicircular blocking covers (3), and the two semicircular blocking covers (3) are in contact with the end faces of the multiple hollow protrusions (2) on the same side.

2. The process for manufacturing a honeycomb-foamed double-layer insulation according to claim 1, wherein In the a step, the conductor needs to be preheated before being placed inside the honeycomb mold cover, and the preheating temperature is set to be in the range of 100-150℃.

3. The process of claim 1 wherein, The pressure of the nitrogen introduced in the c step is kept above 200bar.

4. The process of claim 1 wherein, The film thickness of the extruded inner layer foamed insulation in the d step is set to be in the range of 8-12μm.

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