DD202118A5 - METHOD AND DEVICE FOR PRODUCING COLORED SIGNATING STRIPES ON PLASTIC ENCLOSED STEEL TUBES - Google Patents

Abstract

The invention aims to provide an economically viable method and apparatus for producing a plurality of circumferentially distributed weather-resistant polyethylene marking grids on the surface of polyethylene coated steel tubes, cladding thereof by simultaneously extruding a tubular film of ethylene copolymer and an overlying tubular adhesive Polyethylene film is formed using an extruder head with two ring channels. In order to be able to apply the tube-shaped pressure-sensitive adhesive and jacket foil colored marking strips in the longitudinal direction to the sheathing during extrusion, it is proposed that, for the sheath foil and the marking strips, polyethylene be used with specific melt index and the extruder pressure for sheath foil or the marking strip with a pressure difference between 10 and 50bar to hold. The device is essentially characterized by certain arrangement d. Exit openings for d. Signierungspolyaethylen on the outer annular gap.

Description

-A-

60 717/27

Method and device Generating colored marking strips on plastic-coated steel tubes

Application area of the invention

The invention relates to a method and a device for producing a plurality of circumferentially distributed polyethylene marking strips on the surface of polyethylene pipes coated with polyethylene »

Characteristic of the known n technical solutions

For signing pipes, cables and lines of solid material rails for transfer of ground faults, a variety of methods are used «So, for example, labels with technical information or promotional images and trademarks, WasserwesWEtketts with the same texts or labeling tasks, with dyes (water-soluble or solvent-containing) stenciled Ixte produced by a stamping operation with color deposits, produced by spraying longitudinal signage used and it can also extrude with a color in a different hue than the base material'erfolgen.

The casing of the steel tubes can be formed by simultaneously extruding a tubular film of ethylene copolymer and an overlying tubular polyethylene film serving as a pressure-sensitive adhesive using an extruder head with two annular channels.

Most of these methods do not result in weather-resistant signatures or fail in UV and temperature

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load with changing climatic conditions.

Resistant over a long period of time is a plastic-coated article only if it additionally contains high UV stabilizers in the form of carbon black, acrylate additions or other UY-absorbing admixtures,

Not known are multiply arranged, linear strips that are durable, UY and heat stable, as well as weather resistant and are produced by coloring a variety of types in a continuous operation in extruded form, if at the same time an underlying extruded adhesive represents the adhesion to be coated object and guaranteed.

Object of the invention

The aim of the invention is to provide an economic. lely applicable method and a device for producing weather-resistant colored Signierungsstreifen · on plastic-coated steel pipes,

Explanation of the essence of the invention;

The invention has for its object to provide a method and an apparatus with which it is possible to apply during the extrusion of the tubular pressure-sensitive adhesive and jacket film colored Markierstreifen in the longitudinal direction of the shell, which the purpose of the laid pipes in the ground make it recognizable in every situation. The application should be such that the marking strips are not completely pushed through the thermoplastic sheath and that the physical and chemical properties of the sheath are not impaired, e.g. by notch effects, changes

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elongation at break and chemical behavior, by UV radiation or heat.

The object is ErfindungsgemäS now solved in that for the outer sheath film, a polyethylene having a melt index ig ^ g = 0.4 to 0.5 g / 10 min and for the Signierungsstreifen a dye mixed with a polyethylene having the melt index i _o «c = 0.6 to 0.9 g / 10 min is used and that the marking strips are extruded in a width of 8 mm and with a thickness of 50 to 100 ', \ x simultaneously with the Ummartelung forming tubular film in the longitudinal direction of the tubes, wherein between the extruding pressure for the jacket film and that for the Marking a pressure difference between 10 and 50 bar is maintained.

In the double pointed head used according to the invention, in the area of the ironing zone, ie in the upper third of the outer annular gap (from which the jacket film is extruded), a ring edge is provided with outlet openings for the signing polyethylene distributed over the circumference,

The shape of an extruded sign is limited in a sheath in width and depth, which is pressed continuously in the signing-bearing layer. A lenticular or a planar training of the signing can be achieved by a corresponding pressure difference control. "It is advantageous that for a flush with the mantle surface training of the marking this with a pressure of about 100 bar and the Jacket film are extruded at a pressure of about 150 bar and in the formation of a lenticular cross-sectional shape of the marking strips these with a pressure between 130 and 140 bar and the jacket film 'with a pressure of about 150 bar extruded v / earth.

The shaping is released only by _$ by training

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the distribution channels prevents in-depth penetration »

Ss has also been found that a ₃ signing polyethylene must be (hereinafter briefly called PE) in ig ^ g close to be signed sheathing PE. Example:

Sheathing PE 0.4 - 0.5 Signing PE 0.6 - 0.9

During the extrusion process, the UV and heat-stabilized dye must remain colorfast. This task is easier, the less admixtures (copolymer of PE) are present. Furthermore, there is the Libglichkeit, heat- and UV-stabilized the signing threads not only with color, but form phosphorescent as a luminous color. These measures ensure that the strength properties, tensile strength, tear strength and elongation at break are fully retained and take into account the applicable DIl.

The embodiments can be supplemented in that, in addition to dyeing, a characteristic thread is extruded which identifies perfectly the identity of the plastic-coated article _β

The PS-made selection of signing PE to PE sheath allows for the processing and distribution of the signing PE-S without additional ?? ärine insulation between the extruders because of the extrusion process may be in a uniform Temperaturfuhrung.durchgeführt _o

The device for carrying out the method is characterized in that in the front housing wall of the extruder head, a distributor ring is arranged, which in

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Area of the upper third of the outer annular gap has an annular channel which is connected on the one hand to a serving for supplying the Signierungs-Polyäthyl.ens, extending through the front housing wall channel and the. on the other hand, at least three distributed over its circumference with equally large spacing from one another outlet openings which open in the upper third of the annular gap.

For the sake of clarity ρ i e1

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing show:

1 shows a longitudinal section through the extruder head and the pipe to be covered;

FIG. 2 shows a longitudinal section through the front housing ring of the extruder head; FIG.

Fig. 3ϊ a cross section according to A-Bj and

Fig. 4: a longitudinal section in an enlarged view.

The extruder head used for the extrusion of two tubular films is known per se according to DE-PS 1 957 078 and consists of three housing rings. Here, a first housing ring 1 is integrally formed with a mandrel 2. As seen in the working direction, the housing ring 1, which is provided with an insertion opening, axially adjoins an intermediate ring 3 which, with the conically tapered end section 4 of the mandrel 2, forms an annular gap 5 forms for the inner pressure-sensitive adhesive tube 19. Further, a storage ring 7 is fixed and interchangeable between the intermediate ring 3 and the annular channel 6. While the housing ring 1 for applying the from the annular gap. 5

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emergent inner pressure-sensitive adhesive tube 19 on the au-sheathing tube 17 is used and. is connected for this purpose to the feeder 8, ^ is arranged for the application of the outer Polyäthylenschlsuches 18, a second housing ring which is formed in a similar manner as the housing ring 1 and is closely connected to the side facing away from this of the intermediate ring 3. The annular gap 5 opens immediately before the ring opening of a second annular gap which is formed by the bevelled outer surface of the intermediate ring 3 i nd and by the parallel to this inner surface of the housing ring 9. The annular gap 10 is in communication with an annular channel 11, which is connected to a Polyäthyienzuführung 12 and whose cross section can be changed as in the housing ring 1 by means of a jam ring 13. The housing ring 1, the intermediate ring 3 and the housing ring 9 are connected to each other by screws 14 The heating of the extruder head to the operating temperature is carried out with the controllable heating elements 15th

In the front housing ring 9 of the extruder head, a distributor ring 22 is arranged. "In the region of the ironing zone, ie in the region of the upper third of the outer annular gap 10, this has an annular channel 21 (see Fig. 2 and % This annular channel 21 is connected to a channel). 20, which passes through the front casing ring 9 and serves to feed the signing PE ¹ S. As shown in the figure, the distributor ring 22 (in this example) has four circumferentially uniformly spaced outlet openings 4, which simultaneously produces four marking strips (24) during extrusion and thus ensures that at least one of the strips is visible in each layer of pipe.

Claims (6)

O-7- 60 717/27 Inventionapplication A method of producing a plurality of circumferentially spaced polyethylene signatures on the surface of polyethylene jacketed steel pipes, the jacketing thereof by simultaneously extruding a tubular copolymer of ethylene copolymer and a tubular polyethylene film overlying it as a pressure sensitive adhesive using an extruder head having two Ring channels is formed, characterized in that for the outer cladding film, a polyethylene having a melt index i ₂ * g = 0.4 to 0.5 g / 10 min and for the Signierungsstreifen one with a "Parbstoff mix polyethylene with a melt index I ₂ λc = 0.6 to 0.9 g / 10 min is used and that the Signierungsstreifen be extruded in a width of 8 mm and a thickness of 50 to 100 / U simultaneously with the casing forming tubular film in the longitudinal direction of the tubes, wherein between the extruding pressure for the jacket foil and that for the Sig strip is maintained at a pressure difference between 10 and 50 bar. 2 «method according to item 1, characterized in that for a flush with the mantle surface formation of the marking strips these are extruded at a pressure of about 100 bar and the jacket film at a pressure of about 150 bar. 3. The method according to item 1, characterized in that for the formation of a lenticular cross-sectional shape of the marking strips they are extruded at a pressure between 130 and 140 bar and the jacket film at a pressure of about 150 bar. -S- · 60 717/27 4. A method according to any one of items 1 to 3j S ^e ~ characterized in that the polyethylene for a Signierungsstreifen UY- and heat stabilized dye is added features · 5. Method according to one of the preceding items 1 to 3? characterized in that a phosphorescent dye is added to the polyethylene for the marking stripes. 6. Apparatus for carrying out the method according to the items 1 to 5, with an extruder head, which has two concentrically arranged annular gaps, of which the outer is for extruding the jacket film and the inner for extruding the pressure-sensitive adhesive film, characterized in that in the front Housing wall of the extruder head a distributor ring (22) is arranged, which in the region of the upper third of the outer annular gap (1O) has an annular channel (21) on the one hand an'eine for supplying the signing polyethylene, extending through the front housing wall channel (20) is connected .und the other hand, at least "three over its circumference with equally large spaced distribution outlet openings (23) which open in the upper third of the annular gap (10). - For this 3 pages drawings -