Untitled record

[Detailed Description of the Invention]

A central conductor and a high foaming object insulating layer stick the present invention firmly, and it relates to the method of moreover manufacturing very easily the good high foaming electric insulated wire of an electrical property. Generally, in the high foaming electric insulated wire, in order to stick an insulating layer and a central conductor firmly, the method of providing an adhesives layer on a central conductor is known. Since polarity is so strong that it is desirable as adhesives and a dielectric constant and dielectric loss are large, these adhesives need to make an adhesives layer very thin, in order to make an electrical property good. However, in the extrusion method currently performed from the former as a method of providing an adhesives layer, the solution applying method, the powder flow immersing method, etc., it is difficult for there to be the following faults respectively and to make an adhesives layer very thin. In an extrusion method, since it is easy to carry out a film piece, a film cannot not only [ namely, ] be made thin. Since it is difficult, film thickness becomes uneven and center Agreement of a dice and a nipple is extended as it is, remains distortion is large and sets by the solution applying method, With a diluted solution, since viscosity is low, thickness must be applied several times for making it uniform, In order to be unable to preheat a core material enough since film thickness becomes large naturally and a solvent is moreover used, and to apply [ in / undesirably / safety-and-hygiene top / the powder flow immersing method ] powder, there are many pinholes, and since powder is moreover only melted, the surface has a fault, like film strength is small by unevenness. The present invention applies the principle of "self centering (self-centering) by a floating die (floating die)" which is one view for covering a plastic with an extrusion machine uniformly on a core material conventionally to Craftsman, By covering a very thin adhesives layer (only henceforth a thin film) and carrying out extrusion covering of the high foaming object insulating layer on it continuously on a central conductor by very easy equipment and the working method, without using an extrusion machine, adhesion intensity is large and it manufactures the high foaming electric insulated wire which was moreover excellent in the electrical property. That is, the present invention holds the thin film material which carried out heating fusion more than the temperature which shows heat mobility in the heated iris diaphragm dice, Extrusion covering of the ethylene system quantity foaming insulating material with a foaming magnification of 3 or more times is continuously covered a thin film with the traction of through and a central conductor and carried out on the thin film in a central conductor into it. Although the dice is attached for the floating state, a dice moves free according to change of an extrusion state and self centering is performed in the floating die of the conventional extrusion machine, If it is not necessary to change a dice into a floating state especially in the present invention, this principle is generated by towing a central conductor and a central conductor is made to tow, The passage position of a central conductor moves free according to change of a heat flow state of the thin film material in a dice, and self centering is performed by this. And by the thin film material in a dice being pulled out by the traction of a central conductor in the present invention, and performing churning mixture in a dice automatically, and considering it as an iris diaphragm dice, the Schar (shearing) operation is added at a dice exit, and intensity can be given to a thin film. A drawing is an one example figure of the method of covering thin film material to a central conductor in the present invention, one in a figure is an iris diaphragm dice, and 1' is a dice exit and the thin film with which cover the heating device of dice 1, and 3 to the preheating machine of a central conductor, 4 was covered by the central conductor, and thin film material and 5' were covered [ 2 ] for 5 on central conductor 4. Central conductor 4 preheated with preheating machine 3 is led into iris diaphragm dice 1 in which thin film material 5 which is tinged with heat mobility is held, thin film 5' is uniformly covered with the traction of central conductor 4, and, as for the thin film 5', intensity is given by the Schar (shearing) operation by dice exit 1'. Although the thickness of a thin film is based on the quality of the electrical property of use material, Generally 0.3 mm or less is preferred, and it is an ethylene system as a thin film material, A copolymer is used, it is preferred independent or for the shape to be powdered and to use [ which has a vinyl system other high foaming object insulating layers, and thermal melting arrival nature ] it from a point of the ease of carrying out of fusion, and it should just heat this at more than the melting point of thin film material, and below a thermal decomposition point to make it tinged with heat mobility. For improving adhesion with a thin film and a central conductor, since it is so good that it is high, and it is so good that it is conversely low for covering a thin film uniformly, the preheating temperature of a central conductor and the temperature of thin film material may be suitably chosen according to the purpose of use. The angle of an iris diaphragm dice inside is arbitrarily selectable by the demand characteristics, such as thin film intensity. If the relation between the angle of a dice inside and the demand characteristic of a thin film is shown, it will become as it is shown in the next table. The central conductor with which the thin film was covered as mentioned above is led to an extrusion machine, and is covered with a high foaming insulating material. As a high foaming insulating material, an electrical property and machinery characteristic top ethylene system is independent, or a copolymer is used and the high foaming object in the present invention refers to a thing with a foaming magnification of 3 or more times. Since the method of the present invention attaches easy equipment as shown in a drawing in front of a high foaming extrusion covering device, covers an adhesion material layer, continues and carries out extrusion covering of the high foaming insulating layer, there is also little cost of equipment and it ends, And work is also very easy and it is possible to provide the upper adhesion material layer thinly, And it is protected, without a thin film's coming off or getting damaged, in order to carry out extrusion covering of the high foaming insulating layer at the same process, Since a central conductor does not carry out buckling even if there are effects, like there is no fall of an electrical property and a high foaming insulating layer contracts, since the thin film layer is thin, especially the diameter of a central conductor is comparatively thick, and if it applies to the coaxial cable which has an insulating layer of the degree of high foaming, still much more effect will be accepted. The effect that manufacture of the high foaming electric insulated wire which used the ethylene system quantity foaming insulating material with a foaming magnification of 3 or more times by the method of the present invention was put in practical use is large. Next, the example of the present invention is given. EXAMPLE The iris diaphragm dice heated to 200 degreeC (entrance 20mmphi, exit 4. 8mmphi) The powder of low density polyethylene (density 0, 9. 2, melt index 2.0) is supplied to 30 mm in length, and heat mobilization is carried out, Into this, the central conductor (copper wire of 4.4 mmphi) preheated to 100 degreeC is introduced the speed for 5-m/, and the thin film of about 0.15-mm thickness is covered, Besides, it is thickness 6 about polyethylene foam 6.5 times the foaming magnification of this. Extrusion covering was carried out at 2 mm, and also thinking of the aluminum was covered and carried out as an external conductor, and the high foaming insulation coaxial cable with an external conductor inside diameter of 17.0 mm was obtained. The This is as follows as having measured the characteristic of this cable, and it is the thing outstanding as a coaxial cable, and is Oh. setting in the amount of 75-ohm attenuation of 250 MHz in characteristic impedance 10MHz -- 2 5. 5 in 10~300 MHz of dB/KmVSWR -- 1.1 -- again When it was going to measure the drawing-out power of a central conductor and a high foaming object insulating layer, since adhesion was firm, the foaming object was crushed and it was not able to measure. Comparative example In the example, the high foaming insulation coaxial cable was manufactured completely like the example except not providing the adhesives layer (thin film) formed from low density polyethylene. When the drawing-out power of a central conductor and a high foaming object insulating layer was measured about this cable, it was 0 kg per cable 50cm. moreover -- VSWR at 10~300 MHz is 1.3 or more -- as a coaxial cable, it is use -- it was unsuitable.

[Brief Description of the Drawings]

A drawing is an one example figure which covers an adhesives layer to a central conductor in the present invention.