Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B38/00—Ancillary operations in connection with laminating processes
  • B32B38/04—Punching, slitting or perforating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D88/00—Large containers
  • B65D88/16—Large containers flexible
  • B65D88/1612—Flexible intermediate bulk containers [FIBC]
  • B65D88/165—Flexible intermediate bulk containers [FIBC] with electrically conductive properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
  • B32B2307/202—Conductive
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
  • B32B2307/206—Insulating
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249978—Voids specified as micro
  • Y10T428/24998—Composite has more than two layers

Definitions

• the invention relates to a method for producing an electrically conductive wall provided with an insulating coating from a fabric and film material, in particular for producing fabric webs provided with an insulating coating and having electrically conductive tapes, these materials in particular for producing flexible Bulk containers are used.
• FIBC Flexible bulk containers
• the breakdown voltage must not exceed 4 kV in order to prevent discharges of sliding tufts which can occur on the coating due to high charge potentials. This is indicated by a layer thickness of ⁇ . 30 m reached.
• the fabric underneath is negligible for the dielectric strength, since the fabric made of polypropylene tapes has no higher dielectric strength than air due to its porosity.
• the coating prevents contact with the electrically conductive tapes, so that the risk of the occurrence of tuft discharges which are ignitable for gases and vapors continues to exist.
• the method according to the invention provides for perforating an electrically insulating layer located on a conductive base.
• the insulation of the conductive base is punctually broken, so that the coating is only insignificantly impaired in terms of tightness. Nevertheless is however, the risk of cluster discharges occurring is reduced.
• the perforation is preferably created by electrical breakdown, which makes it possible to create a perforation without damaging the conductive base.
• electrical breakdown is preferably created by electrical breakdown, which makes it possible to create a perforation without damaging the conductive base.
• a perforation without damaging the conductive base.
• a pulse laser used alternatively to create the perforation could not distinguish whether the coating is on an electrically conductive or an electrically insulating base, while a selective selection of the vault areas, namely those into which the electrically conductive ribbons are woven, is automatically possible by electrical breakdown.
• the investment values for a technology based on electrical breakdown are much cheaper than e.g. with a laser technique.
• the coated carrier material is guided over an electrically insulating roller which serves as a support and is opposite the high-voltage electrode.
• the carrier material preferably runs simultaneously over a second roller which is designed to be electrically conductive and is connected to the opposite pole of the high-voltage source which is at ground potential. This provides contact with the conductive base or the incorporated, cross-linked ribbon, so that it is at a defined potential and forms the counter electrode to the high-voltage electrode.
• the electrical breakdown takes place between the electrode and the conductive base or the incorporated ribbon.
• the breakdown current flows through the electrically conductive, grounded base.
• the formation of the support base as a roller or roller offers the possibility of a more precise determination of the location with the least distance to the electrode compared to a plane; The electrical breakthrough then takes place between this and the high-voltage electrode.
• the electrode is expediently designed as a tip, so that an exact positioning of the perforation is possible.
• the design of the support base as a roller or roller also enables the material to be transported translationally along the electrode.
• the setting of the transport speed and the frequency of the alternating high voltage applied or, in the case of direct voltage, the choice of the series resistor allow the perforation density to be varied.
• the distance between electrode and coating material is preferably adjustable, so that it can be optimized for the respective carrier material layer material.
• an electronically conductive base 3 coated with an electrically insulating layer 2 is guided over an electrically insulating roller 4, which is positioned opposite an electrode 5 which is subjected to high voltage.
• the base 3 is either made entirely of conductive material, or it consists of an insulating fabric into which conductive, network-like tapes are woven.
• the coated material 6 lies on the roller 4 in such a way that the coating faces the electrode 5 and the conductive base 3 runs directly over the roller 4.
• the material 6 with the conductive base 3 runs over a second roller 7, which is electrically conductive and is connected to the opposite pole of the high voltage source 8, which is at ground potential.
• the roller 7 engages with the electrically conductive base 3 or the network-like, conductive ribbon that there is contact and the conductive base lies at a defined earth potential via the output of the voltage source 8.
• the material 6 itself is unwound from a supply and moves over the roller 4 and the roller 7 at a speed of 0.5 m / s to 5m / s.
• a high voltage generated by the high-voltage source 8 is applied to the electrode 5 and can be set between 8 and 15 kV.
• a spark gap is formed between the electrode 5 which is at high voltage and the electrically conductive base 3 which is at earth potential and thus acts as a counterelectrode, which is broken down when a breakdown voltage U is reached.
• This voltage depends on the distance between the electrode 5 and the conductive base 3, on the coating material used and on the layer thickness. Since the electrically conductive base 3 runs on an electrically insulating roller 4, an electrical breakdown occurs only between the electrode 5 and the conductive base 3 or a ribbon. If insulated tissue webs pass through the electrode 5, no electrical breakdown can take place, since no spark gap is formed; ie, pores are formed only in the coating area which rests on an electrically conductive base 3.
• a temporal control of the applied high voltage is necessary.
• a series resistor 9 is connected between high voltage source 8 and electrode 5.
• FIG. 2 shows the voltage profile 10 over time of the voltage applied to the electrode 5 in the event that a DC voltage source is used.
• the time t of the voltage rise to the value U is determined by the capacitance C of the capacitor formed from the electrode tip 5 and the conductive base 3 or conductive ribbon and the series resistor 9 according to the time function Tr - R "C.
• the capacitor is connected via the series resistor 9 charged in the time t and when the breakdown voltage U is reached, the breakdown occurs spontaneously with simultaneous discharge of the capacitor. This ends the breakdown process and creates a pore.
• the capacitor recharges until the breakdown voltage is reached U and the defined capacitance C, the breakdown frequency is determined by the series resistor 9.
• FIG. 3 shows the voltage profile 11 over time of the voltage applied to the electrode 5 in the event that an AC voltage is applied.
• the breakdown frequency is determined here solely by the frequency of the AC voltage.
• the voltage obtained from the high-voltage source 8 is selected such that the breakdown voltage U 1 is reached shortly before each positive or negative peak pass of this voltage and breakdown occurs.
• the series resistor 9 has the task of controlling the supplied electrical energy and thus the pore size: E in a small series resistor creates large pores, with increasing resistance the pore size decreases.
• the air gap 12 for the breakdown spark becomes larger, i.e. the breakdown voltage U required becomes higher. If the voltage at the high-voltage source is chosen so high that it leads to breakdown even when the ribbon is furthest away from the electrode tip 5, the distance would be smaller
• Electrode tip ribbon introduced a larger spark energy and thus creates a larger pore. It is therefore expedient to position a plurality of electrode tips 5 next to one another in a common arrangement such that they can correspond to the lateral ribbon fluctuations.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Elimination Of Static Electricity (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=6483911

Family Applications (1)

Country Status (4)

Families Citing this family (1)

Family Cites Families (8)

• 1994
  • 1994-02-04 JP JP52157994A patent/JPH08502448A/ja active Pending
  • 1994-02-04 EP EP94906218A patent/EP0641260A1/de not_active Withdrawn
  • 1994-02-04 US US08/343,578 patent/US5562948A/en not_active Expired - Lifetime
  • 1994-02-04 WO PCT/EP1994/000316 patent/WO1994022597A1/de not_active Application Discontinuation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events