RU2016426C1 - Insulated multistrand conductor manufacturing process - Google Patents

Abstract

FIELD: cable manufacture. SUBSTANCE: central wire of conductor is covered with layer of polymeric composition based on polyolefins with Shore hardness not lower than 30, external strands are arranged about it, then conductor is covered with polyolefins base composition at temperature affording fusion of coating material. Provision is also made for surrounding central wire with strands alternating with those covered with mentioned composition. EFFECT: provision for longitudinal sealing of conductor and reduced longitudinal shrinkage of insulation. 2 cl

Description

 The invention relates mainly to the production technology of cable products, in particular insulated conductors of wires and cables with plastic insulation, and can also be used in the manufacture of other products twisted from wires, for example, polymer coated cables.

 The purpose of the invention is the provision of longitudinal sealing of the core while reducing longitudinal shrinkage of the insulation.

 When implementing the method, polymer compositions based on polyolefins having a Shore hardness of at least 30, preferably 30-90, for example, compositions based on high pressure polyethylene, low pressure polyethylene, ethylene vinyl acetate copolymer, are used as coating material for individual wires of the core.

 The insulation is extruded onto the core preform at a temperature at least equal to the melting temperature of the coating material, but not higher than the temperature of thermal destruction of the coating material. The temperature of the extrusion of insulation is selected depending on the cross section of the conductive core, the thickness of the insulation, the speed of extrusion of insulation and the use of preheating the billet of the core before it enters the head of the extruder. In any case, the temperature of extrusion of the insulation is selected from the condition of ensuring the melting of the coating material.

 The following are examples of the invention (1-5) and control examples (6-9). In all examples, the polymer coating on individual wires of the core is extruded on a VM-30 extruder with a screw diameter of 30 mm, the core preparation is twisted on a KS-12 cigar-type twisting machine, and the insulation is extruded onto the core preparation on an Anduart-60 extruder with a 60 mm diameter screw .

EXAMPLE EXAMPLE 1 In a copper wire with a diameter of 0.3 mm at a temperature of extruder head 200 ^{° C} is extruded coating radial thickness of 0.15 mm mark 107-02K composition based on high density polyethylene having a Shore hardness of 90. Then twist the core blank with a cross section of 0.5 mm ^{2 of a} design of 7x0.30 mm, placing an outer coil of six bare copper wires around a central wire with an extruded coating. The resulting preform prior to entering the extruder head for applying insulation preheated using heated gauge at 130 ° ^C. The parison isolate the same composition 107-02K mark. Extruding the insulation is performed at a temperature of extruder head 220 ^° C Diameter of core 1.95 mm.

PRI me R 2. On a copper wire with a diameter of 0.42 mm at a temperature on the head of the extruder 210 ^o With extruded coating of a radial thickness of 0.15 mm from silanol-crosslinked composition grade 158-201 based on high-pressure polyethylene having a Shore hardness of 80 Then twist the core blank with a cross section of 1.0 mm ^{2 of a} design of 7x0.42 mm, placing an outer coil of six bare copper wires around a central wire with an extruded coating. The resulting preform is isolated with the same composition of the brand 158-201. Extruding the insulation is performed at a temperature of extruder head 225 ^° C Diameter of core 2.45 mm.

EXAMPLE EXAMPLE 3. copper wire with a diameter of 0.42 mm at a temperature of extruder head 200 ^{° C} is extruded coating radial thickness of 0.15 mm mark 107-02K composition based on high density polyethylene having a Shore hardness of 90. Then twist the workpiece core with a cross section of 2.5 mm ² design 19x0.42 mm. When twisting, a wire with an extruded coating is placed in the center of the workpiece, a twist of three bare copper wires alternating with three wires with an extruded coating is placed on the central wire, after which an outer twist of twelve bare copper wires is placed. The resulting preform prior to entering the extruder head for applying insulation preheated using heated gauge at 130 ° ^C. The parison isolate the same composition 107-02K mark at a temperature of extruder head 230 ^° C Diameter of core 3.30 mm.

PRI me R 4. On a copper wire with a diameter of 0.42 mm at a temperature on the extruder head of 150 ^about With extruding a coating of a radial thickness of 0.12 mm from a composition based on a copolymer of ethylene with vinyl acetate, having a shore hardness of 30. Then twist the workpiece veins with a cross section of 1.0 mm ^{2 of a} design of 7x0.42 mm, having an outer core of six bare copper wires around a central wire with an extruded coating. The resulting preform prior to entering the extruder head for applying insulation preheated using heated gauge at 130 ° ^C. The parison is isolated mark 153-01K composition based on high density polyethylene. Extruding the insulation is carried out at a temperature of extruder head 200 ^° C Diameter of core 2.20 mm.

EXAMPLE 5. EXAMPLE On a copper wire with a diameter of 0.30 mm at a temperature of extruder head 200 ^{° C} is extruded coating radial thickness of 0.15 mm mark 107-02K composition based on high density polyethylene having a Shore hardness of 90. Then twist the workpiece with a cross section of 0.5 mm ² design 7x0.30 mm, placing around the central wire with extruded coating an outer twist of six bare copper wires. The resulting preform prior to entering the extruder head for applying insulation preheated using heated gauge at 130 ° ^C. The parison isolate composition 206-07K mark based on low pressure polyethylene. Extruding the insulation is performed at a temperature of extruder head 260 ^° C Diameter of core 1.93 mm.

PRI me R 6 (control). On a copper wire of 0.30 mm diameter at a temperature in the die 100 ^{° C} is extruded coating radial thickness of 0.15 mm from the composition based on polyisobutylene having a Shore hardness of 7. Then twisted core preform cross-section 0.5 mm ² 7h0,30 structure mm, having an outer core of six bare copper wires around a central wire with an extruded coating. The resulting preform is isolated with a composition of the brand 206-07K based on low-pressure polyethylene. Extruding the insulation is performed at a temperature of extruder head 260 ^° C Diameter of core 1.92 mm.

PRI me R 7 (control). On a copper wire of 0.30 mm diameter at a temperature in the die 115 ^{° C} is extruded coating radial thickness of 0.15 mm from the composition based on a mixture of EPDM rubber stamps dielectric EPDM-butyl rubber and 40D BC-2045 brand, having a Shore A hardness of 18. Then twist the core blank with a cross section of 0.5 mm ^{2 of a} design of 7x0.30 mm, placing an outer coil of six bare copper wires around a central wire with an extruded coating. The resulting preform prior to entering the extruder head for applying insulation preheated using heated with a temperature gauge 100 ^C. The parison isolate composition 206-07K mark based on low pressure polyethylene. Extrusion is performed at a temperature of extruder head 265 ^° C Diameter of core 1.95 mm.

PRI me R 8 (control). On a copper wire of 0.30 mm diameter at a temperature in the die 100 ^{° C} is extruded coating radial thickness of 0.12 mm from the composition based on polyisobutylene having a Shore A hardness of 10. Then the twisted core preform cross-section 0.5 mm ² Construction 7h0,30 mm, having an outer core of six bare copper wires around a central wire with an extruded coating. The resulting preform is isolated with a composition of the brand 271-70K based on low-pressure polyethylene. Extruding the insulation is performed at a temperature of extruder head 270 ^° C Diameter of core 1.90 mm.

PRI me R 9 (control). On a copper wire of 0.42 mm diameter at a temperature in the die 100 ^{° C} is extruded coating radial thickness of 0.15 mm from the composition based on polyisobutylene having a Shore hardness of 7. Then twisted core preform cross-section 1.0 mm ² 7h0,42 structure mm, having an outer core of six bare copper wires around a central wire with an extruded coating. The resulting preform is isolated with a composition of grade 107-02K based on high-pressure polyethylene. Extruding the insulation is performed at a temperature of extruder head 220 ^° C Diameter of core 2.35 mm.

 In the above examples, the temperature regime of the extrusion of insulation provides heating and melting of the coating material of the wires of the core.

Shrinkage insulation stranded lived determined at temperatures of 20 ^{° C} and 70 ° ^C by the method described in IEC 12175-73 "Cables, wires and cords. Methods for the determination of shrinkage of the insulation compositions of polyethylene and PVC-compound" and the corresponding methods of international standards IEC 811, IEC 92.

 The design of multi-wire insulated cores made in accordance with examples 1-9, and the values of shrinkage of their insulation are given in the table.

 For comparison, the construction and shrinkage values of the insulation of a multi-wire core made by a known method that does not provide for coating individual wires of a core are also given there.

As follows from the data given in the table, for multi-wire insulated cores made according to the invention, insulation shrinkage is absent (examples 1-3 and 5) or very small (example 4). At the same time, in multi-wire insulated conductors that contain wires with coatings of materials with Shore hardness below 30 (control examples 6–9), the insulation shrinkage is 0.8–1.3% after holding for 72 hours at a temperature of 20 ^about C and 4.1-5.9% after the same exposure at a temperature of 70 ^about C.

Shrinkage in multiwire conductor insulation made by a known method, was 0.4% after aging for 72 hours ^at 20 ° C and 2.9% after the same exposure to a temperature of 70 ° ^C.

Samples of multi-wire insulated cores made according to examples 1-9 and by a known method, were tested for longitudinal tightness. All samples, except those made by a known method, withstood exposure to gas pressure of 20 kg / cm ² for 2 hours. The passage of gas bubbles from the opposite end of the core immersed in water was not observed.

 Thus, the invention provides minimal shrinkage of the insulation and the longitudinal tightness of the multi-wire insulated core without the consumer having to perform any special installation operations.

Claims (2)

 1. METHOD FOR MANUFACTURE OF MULTI-WIRE INSULATED VEIN, in which an outer wire is placed around the central wire, the insulation is extruded from the polymer composition based on polyolefins onto the billet, characterized in that, in order to ensure longitudinal sealing of the core while reducing longitudinal insulation shrinkage, the central wire used is an extruded coating of a polymer composition based on polyolefins with a Shore hardness of at least 30, and extruding from The radiation is produced at a temperature that ensures the melting of the coating material.  2. The method according to claim 1, characterized in that the center wire is imposed by a twist of wires alternating with wires with an extruded coating of a polymer composition based on polyolefins with a Shore hardness of at least 30, after which an outer twist is placed.

Images