RU2511441C1 - Application method of insulation coating on metal wire - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method involves application of an adhesive layer based on a thermoplastic adhesive and further application of a functional layer from nanostructured polymer composite material based on polyethylene with disperse filler from montmorillonite. The adhesive layer is applied by wire drawing through molten thermoplastic adhesive. The functional layer is applied by extrusion.

EFFECT: invention allows increasing physical and mechanical and operating characteristics of the coating and simplifying a procedure for obtaining a coating.

9 cl, 2 dwg, 1 ex

Description

The invention relates to methods for applying insulating coatings to metal wires and can be used, in particular, for coating wires intended for the manufacture of mesh (wicker) and other products.

The prior art method for applying an insulating coating to a wire, including applying a polymeric material (polyethylene, PVC) by extrusion using an angled extrusion head (found on the Internet http://plastichelper.ru/biblioteka-on-line-about-polimers/52 -technology-of-polimers / 255-48-nanesenie-pokrytij-na-provoda-i-kabeli).

The disadvantage of this method is the low level of adhesion of the polymer material to the metal of the wire.

It should also be noted that the application of an insulating coating of polyethylene or PVC will not provide the required level of physical, mechanical and operational properties of the wire.

The objective of the claimed invention is to apply a coating having, in particular, the following properties:

- high resistance to cracking,

- high resistance to aggressive environments (corrosion resistance),

- high heat resistance,

- high frost resistance,

- high adhesion to metal wire,

- high wear and abrasion resistance,

The technical result of the invention is to increase the physico-mechanical and operational characteristics of the coating, as well as to simplify the technology.

The specified technical result of the invention is achieved due to the fact that the method of applying an insulating coating to a metal wire involves applying an adhesive layer based on thermoplastic adhesive and then applying a functional layer of a nanostructured polymer composite material based on polyethylene with a dispersed filler of montmorillonite, while the adhesive layer is applied by pulling the wire through the melt of thermoplastic adhesive, and the functional layer is applied by extrusion and composite polymer material.

In addition, the specified technical result is achieved in special cases of the invention due to the fact that:

- for applying the adhesive layer using a melt of glue, heated to a temperature of 150-180 ° C;

- after applying the adhesive layer, the wire is pulled through a heated caliber, which ensures the removal of excess thermoplastic glue;

- before applying the functional layer, the wire is heated to the softening temperature of the thermoplastic adhesive;

- the wire is heated by means of a radiator to a temperature of 90-95 ° C;

- for applying the functional layer using a composite material containing 0.1-2 wt.% montmorillonite;

- for applying the functional layer using an angular extrusion head;

- after applying the functional layer, the wire is cooled in a bath with water circulation;

- the adhesive coating layer is applied with a thickness of less than 1/10 of the thickness of the functional layer,

while the total coating thickness is at least 0.5 mm

Due to the application of an adhesive layer of thermoplastic adhesive, the adhesion of the coating to the metal base is significantly increased, and therefore, the resistance of the coating to peeling and damage due to mechanical and other influences is increased. The application of a functional layer of nanostructured polymer composite material (PCM) based on polyethylene with a dispersed filler of montmorillonite increases the above-mentioned physical, mechanical and operational characteristics of the coating and wire as a whole. Moreover, the use of in-line technology of applying layers (pulling the wire through the melt of glue followed by extrusion of the polymer composite) greatly simplifies the implementation of the claimed method.

The claimed method is illustrated in figure 1, which shows the production line for implementing the method, and figure 2, which shows the design of the extrusion head used in the method.

The claimed method is implemented as follows.

To apply the adhesive layer, the metal wire 1 is pulled through rollers 2 through a bath 3 with molten thermoplastic adhesive (hot melt adhesive). Preferably, the adhesive has a temperature of 150-180 ° C. Thermoplastic adhesive is able to repeatedly pass into the melt when heated and solidify when cooled, while it fills the voids well, has low shrinkage and high mechanical strength. The thermoplastic adhesive used in the claimed method may include the following main components: ethylene vinyl acetate, paraffin wax, ether naphtha, and also include a mineral filler and antioxidant.

After applying the glue, if necessary, the wire 1 is pulled through a heated gauge 4, designed to remove excess glue. It is preferable that the open exposure time of the adhesive was less than 1 second. Such a short time is due to the high speed of the coating, as well as the need to preserve the glue on the surface of the wire (without dripping). In this case, the glue hardens.

Then, preferably, the wire 1 is heated using an infrared emitter 5 to the softening temperature of the thermoplastic adhesive (about 90-95 ° C). This operation allows you to further increase the adhesion of the polymer functional layer, however, is not strictly required.

Next, the functional coating layer is applied by extruding the molten composite polymer material in a single screw extruder 6 using an angled extrusion head 7 (FIG. 2). Such a head 7 has a matrix (die) 8 and mandrel 9.

As the material of the functional layer, a nanostructured bimodal polymer composite material based on polyethylene (matrix) with dispersed filler of montmorillonite (nanomodifier) is applied. Montmorillonite (MMT or "nanoclay") is a silicate having a layered structure. Preferably, in the composite coating material MMT had a lamellar particle shape, with dimensions: length 100-200 nm, thickness 2-6 nm. These montmorillonite particles form a nanostructure that provides polymer structuring at the time of crystallization (nucleation effect), increasing the physicomechanical properties of the material (strength, elastic modulus, frost resistance), as well as its barrier properties (gas and vapor permeability decreases), which increases the corrosion resistance of the material . Moreover, the most optimal content of montmorrilonite in the composite material is 0.1-2 wt.%.

Preferably, the adhesive coating layer has a thickness of less than 1/10 of the thickness of the functional layer, while the total coating thickness is at least 0.5 mm.

After applying the functional layer, if necessary, the wire is cooled in a bath 10 with water circulation and wound using a winding device 11.

An example implementation of the method

The coating is applied to a steel wire with a diameter of 2.7 mm GOST 3282-74 from heat-treated low-carbon steel with zinc coating according to GOST R 50575-93.

The wire is pulled through a bath with a heated Flexamet 104 brand thermoplastic adhesive heated to a temperature of 150-180 ° C. When leaving the bath, the adhesive freezes on the surface. Then the excess glue is removed using a caliber heated to a temperature of 150 ° C.

Next, the resulting wire is heated using a radiator to an adhesive softening temperature of 90-95 ° C and a functional layer is applied by extruding a polymeric composite material based on polyethylene containing 0.1-2% montmorillonite at a temperature of 200-210 ° C using an angled extrusion head . Then the wire is cooled in water.

The wire feed speed during the implementation of the method is 100-200 m / min.

Thus, the claimed method allows you to apply coatings with improved performance while simplifying the application technology.

It should be noted that the claimed invention is not limited to the particular cases of its implementation disclosed in the description. There are also other forms of execution of the considered method in the amount of the essential features of the invention.

Claims (9)

1. A method of applying an insulating coating to a metal wire, comprising applying an adhesive layer based on thermoplastic adhesive and then applying a functional layer of a nanostructured polymer composite material based on polyethylene with a dispersed filler of montmorillonite, wherein the adhesive layer is applied by pulling the wire through a melt of thermoplastic adhesive, and the functional layer is applied by extrusion of a composite polymer material. 2. The method according to claim 1, in which for applying the adhesive layer using a melt of glue, heated to a temperature of 150-180 ° C. 3. The method according to claim 1, in which after applying the adhesive layer, the wire is pulled through a heated caliber, providing removal of excess thermoplastic adhesive. 4. The method according to claim 1, in which before applying the functional layer, the wire is heated to the softening temperature of the thermoplastic adhesive. 5. The method according to claim 4, in which the wire is heated by means of a radiator to a temperature of 90-95 ° C. 6. The method according to claim 1, in which for applying the functional layer using a composite material containing 0.1-2 wt.% Montmorillonite. 7. The method according to claim 1, in which for applying the functional layer using an angular extrusion head. 8. The method according to claim 1, in which after applying the functional layer, the wire is cooled in a bath with water circulation. 9. The method according to claim 1, characterized in that the adhesive coating layer is applied with a thickness of less than 1/10 of the thickness of the functional layer, while the total coating thickness is at least 0.5 mm.

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