Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
  • D21H21/42—Ribbons or strips

Definitions

• the present invention relates to an improved process for the preparation of security threads suitable for use in security articles.
• Security documents such as bank notes, stocks, bonds, checks, warrants and identification cards need to be guarded by antifalsification measures and they are often made from a security paper having a security element in the form of fibers, strips or threads embedded therein.
• GB 2,213,098 discloses a partially metallized film strip, used as a security thread, which has metal-free portions in the form of a pattern, design, indicia, etc. to provide a continuous metal path along the length of the strip ' .
• Japanese Laid-open Patent Publication No. 216795/1988 teaches a security strip having a metallized pattern on the surface of a transparent film.
• an object of the present invention to provide an improved process for preparing a security thread suitable for use in a security paper.
• a process for the preparation of a security thread having a partially metallized layer which comprises: forming a water-soluble ink layer on a selected portion of the surface of a transparent film; depositing a layer of a metal selected from the group consisting of aluminum, tin, silver and an alloy of cobalt and nickel on the entire surface of the transparent film including the water-soluble ink layer; and washing the metal deposited film with water to ' remove the portion of the metal layer deposited on the water-soluble ink layer.
• Figs. 5 to 8 illustrate other embodiments of security threads prepared in accordance with the inventive process.
• a water-based ink which is soluble in water, is printed on a selected portion of the surface of a transparent film substrate, in the form of a character, pattern or figure to form a partial water- soluble ink layer.
• the substrate may be made from any material known in the art such as a polyester (e.g., polyethylene terephthalate (PET) ) , polyvinyl chloride, polypropylene and the like.
• PET polyethylene terephthalate
• the water-based ink may be any one conventionally used in the art.
• a layer of a metal is deposited on the entire surface of the film including the printed ink layer.
• the deposition may be carried out by vacuum deposition methods which are well known by a skilled person in the art.
• Representative examples of the metal suitable for forming the metal layer are aluminum, tin, a metal alloy (e.g., Co and Ni) , silver and the like.
• the thickness of the metal layer ranges from 1 A to 2 ⁇ m.
• the metal-deposited film is washed with -4- water, preferably with brushing, to remove the portion of the metal layer deposited on the water-soluble ink layer, to obtain a film having a partially metallized layer.
• a security thread having a enhanced security feature may be obtained by employing a fluorescent pigment or dyestuff to provide a partially metallized film having both a demetallized portion and a dyed portion.
• a partial coating of the fluorescent pigment or dyestuff is applied to a selected portion of the film surface prior to the step of printing the water-soluble ink.
• the water-soluble ink layer may be so formed as to mask the dyed portion.
• the fluorescent pigment or dyestuff may be any one conventionally used in the art and the coating thereof may be applied in the form of a character, pattern or figure, or a combination thereof, preferably by a gravure printing method.
• the security thread of the present invention has a thickness and width suitable for use in security documents, e.g., a thickness ranging from about 15 to 35 ⁇ m and a width ranging from 0.5 to 5 mm.
• the security thread of the present invention may be preferably embedded between two sheets of paper formed separately on a paper making machine and subsequently brought together to form a security paper having an embedded security thread.
• Figs. 1 to 4 show the steps of forming a partially- metallized film having a transparent region in the form of a set of characters and a dyed region in the form of another set of characters in accordance with one embodiment of the present invention.
• a fluorescent dyestuff or pigment composition such as Lumilux CD 305, CD 316 or Papilion is applied in the form of a set of characters (2) on the surface of a transparent polyester substrate (10) at a regular interval by a gravure printing method.
• a water-based ink is printed on the film to form a mask (30) of the printed characters portion (2) and, simultaneously, a design (31) in the form of another set of characters .
• Aluminum is deposited on the resulting film by a vacuum deposition method to form an aluminum layer (4) at a thickness of 1 A to 2 ⁇ m over the entire surface of the film, as shown in Fig. 3.
• an aluminum-deposited film (1) comprising transparent characters (5) (corresponds to the design (31) ) and printed characters (2) positioned in a transparent region (10) .
• Figs. 5 to 8 illustrate other embodiments of security threads prepared by the inventive process.
• -6- Fig. 5 shows a security thread (1) having alternating metal- deposited portion (4) comprising transparent characters (5) , and transparent substrate region (10) comprising colored characters (2) at a regular interval.
• a metallized security thread (1) having various patterns of colored regions (2) , optionally positioned in transparent regions.
• Fig. 7 shows a security thread (1) produced by forming metallized bands (4) in a regular pattern on a transparent base film (10), and
• Fig. 8 shows a security thread (1) obtained by a chain of imprinting alternating colored (2) and metallized links (4) on a base film (10) .

Landscapes

• Paper (AREA)
• Credit Cards Or The Like (AREA)
• Laminated Bodies (AREA)
• Printing Methods (AREA)
• Polymerisation Methods In General (AREA)
• Air Bags (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19534044

Family Applications (1)

Country Status (8)

Cited By (5)

Families Citing this family (5)

Citations (2)

• 1998
  • 1998-03-02 KR KR1019980006706A patent/KR19990073639A/ko not_active Application Discontinuation
• 1999
  • 1999-02-26 AT AT99906557T patent/ATE304627T1/de not_active IP Right Cessation
  • 1999-02-26 RU RU2000124869/12A patent/RU2188268C2/ru active
  • 1999-02-26 WO PCT/KR1999/000089 patent/WO1999045199A1/en active IP Right Grant
  • 1999-02-26 EP EP99906557A patent/EP1064424B1/de not_active Expired - Lifetime
  • 1999-02-26 CN CN99803609.9A patent/CN1107764C/zh not_active Expired - Lifetime
  • 1999-02-26 DE DE69927248T patent/DE69927248T2/de not_active Expired - Lifetime
  • 1999-02-26 ES ES99906557T patent/ES2245090T3/es not_active Expired - Lifetime

Patent Citations (2)

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