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
  • D21H21/28—Colorants ; Pigments or opacifying agents
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C3/00—Packages of films for inserting into cameras, e.g. roll-films, film-packs; Wrapping materials for light-sensitive plates, films or papers, e.g. materials characterised by the use of special dyes, printing inks, adhesives

Definitions

• This invention relates to a black dyed paper having particular utility in the packaging of light-sensitive photographic materials, and to a process of making the same.
• interleaving paper In the packaging of certain light-sensitive photographic materials such as sheet film it is desirable to place what is known as interleaving paper between each sheet of film. Such paper should not transmit light and should have the quality of minimizing the accumulation and discharge of static electricity, that is it should have a very high electrical resistance (above eighty thousand ohms per square inch). Paper is that it must be photographically inert, that is, its coloring material must not contain any substance such as sulfur which will tend to cause fogging or" the lightsensitive emulsion or other layer forming part of the photographic material with which the paper is used.
• a black photographic packaging paper having the desired properties and particularly useful for interleaving purposes between sheet film, can be provided by a new process which includes the dyeing of the paper pulp with certain specific types of black dyes, such as duPont Fiber Black VF or Diamine Black Cap Extra Conc., preferably modified by a small amount of a yellow dye such as duPont Pontamine yellow SXPE.
• black dyes such as duPont Fiber Black VF or Diamine Black Cap Extra Conc.
• a dye such as Direct D Black EA Extra CF, Color Index No. 581 can be used without addition of yellow. All such dyes must be salt free.
• the making of the paper includes certain novel steps such as the maintaining of aluminum sulfate in the paper at a minimum amount so that the electrical resistance of the paper can be controlled at a figure above about 80,000 ohms per square inch.
• Beater time is minimized to lower the hydration of the pulp fiber and thereby to lessen cockle in the finished paper, which might in turn effect pressure desensitization of the film or other material with which the paper is used. Hydration is also minimized by using a so-called sharp equipment in the beater and Jordan to give a clean-cut fiber without fuzzing and opening of the fiber ends.
• a black interleaving paper for use with light-sensitive materials, which paper combines the desirable properties of not transmitting light, having a high electrical resistance so as to minimize static, being free of sulfur-containing dyes and other materials which would be likely to cause fogging of the light-sensitive material, and being A third important property of such States Patent O ice free of any coloring materials which cause smudging. It is also an object of the invention to provide a method of producing such paper.
• DuPont Fiber Black VF 12 pounds Pontamine Yellow SXPE 3,600 gallons water
• DuPont Fiber Black VF is salt free and is believed to be color index No. 581. This dye is believed to be:
• the yellow dye is the sodium salt of dinitro azo distilbene tetra sulfonic acid, index No. 622, of the following structure:
• a very desirable paper is obtained by using the black dye alone, but the use of the yellow dye has the important advantage of improving the appearance of the paper by reducing the somewhat blue-black appearance and rendering the paper a deeper black color.
• the ingredients are mixed with water in the beater at F. for two hours at 6% consistency and are then put through a Jordan at 4% consistency. The mix then goes directly to the paper making machine Without any size being applied. It is important that the dyes used be salt free and that the aluminum sulfate content of the paper be controlled so" that the resistance of the finished paper can be controlled at a figure above 80,000 ohms per square inch.
• the beater time is minimized to lower the hydration of the pulp fiber and thereby lessen cockle in the finished paper as such cockle might efiect pressure desensitization of the film or other light-sensitive material.
• So-called sharp equipment is used in the beater and Jordan to give a clean-cut fiber without fuzzing and opening of the fiber ends thus assisting in minimizing hydration.
• This paper gave excellent nonscuffing properties with a rich deep black.
• the following black dye can also be used, and yellow dye need not be used with this dye, even though it has a similar structure: Direct D Black EA Extra CF Color Index No. 581.
• a photographically inert, nonsmudging, nonlighttransmitting, nonpressure desensitizing black paper for use as interleaving paper in the packaging of light-sensitive photographic materials, said paper having an electrical resistance of over 80,000 ohms per square inch and containing a salt free black dye which is also free of any ingredients likely to cause fogging of light-sensitive material.
• a black interleaving paper according to claim 3 wherein said yellow dye is duPont Pontamine Yellow, index No. 622.
• a black interleaving paper as set forth in claim 1 having the following ingredients:

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• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Paper (AREA)

Priority Applications (5)

Applications Claiming Priority (1)

Publications (1)

Family

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Family Applications (1)

Country Status (5)

Cited By (3)

Citations (4)

• 0
  • BE BE523132D patent/BE523132A/xx unknown
• 1952
  • 1952-10-01 US US312634A patent/US2710800A/en not_active Expired - Lifetime
• 1953
  • 1953-08-15 DE DEE7689A patent/DE958354C/de not_active Expired
  • 1953-09-29 FR FR1084103D patent/FR1084103A/fr not_active Expired
  • 1953-10-01 GB GB26952/53A patent/GB748520A/en not_active Expired

Patent Citations (4)

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