Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Composite having voids in a component
Reexamination Certificate
1999-12-22
2002-08-27
Chen, Vivian (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Composite having voids in a component
C428S314400, C428S315500, C428S317900, C428S458000, C428S480000, C428S483000, C428S910000, C430S523000, C430S524000, C430S531000, C430S533000, C430S534000
Reexamination Certificate
active
06440548
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to imaging materials. In a preferred form, it relates to base materials for photographic reflective paper.
BACKGROUND OF THE INVENTION
In the formation of color paper it is known that the base paper has applied thereto a layer of polymer, typically polyethylene. This layer serves to provide waterproofing to the paper, as well as providing a smooth surface on which the photosensitive layers are formed. The formation of a suitably smooth surface is difficult, requiring great care and expense to ensure proper laydown and cooling of the polyethylene layers. Such a smooth surface requires a great deal of care and expense associated with chill rolls. There is a need for a photographic color print material that has a polyethylene surface but does not require chill rolls for the formation of a glossy surface.
In photographic papers the polyethylene layer also serves as a carrier layer for titanium dioxide and other whitener materials as well as tint materials. It would be desirable if the colorant materials rather than being dispersed throughout the polyethylene layer could be concentrated nearer the surface of the layer where they would be more effective photographically.
In photographic paper the polyethylene layer provides a means of containing TiO
2
. The TiO
2
provides a highly reflective layer directly under the light sensitive layers to provide image sharpness and opacity. Prior art photographic reflective paper use white pigments, typically TiO
2
and blue colorants to provide a white support and improve image sharpness during exposure by preventing the exposure light from reaching the paper fibers where the light is scattered and reflected back to the imaging layers. It has been found that while the TiO
2
does improve image sharpness and does provide a white support and opacity, TiO
2
below the imaging layers corrupts the dye hue angle of photographic dyes, changing the dye hue angle away from the perceptually preferred hue angle of the dyes. It would be desirable if a support material has the image sharpness, opacity and whiteness of prior art color papers without the use of white pigments in the support. It would be desirable if TiO
2
did not have to be directly under the light sensitive layer or even be present in a photographic element. There remains a need to provide added opacity and whiteness without the use of expensive white pigments.
Prior art photographic support materials typically utilize melt extruded polyethylene to waterproof the paper during the wet processing of images during the image development process. The gelatin based light sensitive silver halide emulsion generally adheres well to the polyethylene layer during manufacturing and wet processing of images. It would be desirable if a biaxially oriented sheet contained an integral bonding layer to provide emulsion adhesion during emulsion coating and the wet processing of images during the image development step.
Present photographic papers generally being constructed of polyethylene coated cellulose paper, can be easily damaged, torn or abraded as images are viewed by consumers over the lifetime of an image. It would be desirable if a photographic support were more tear resistant, offering the consumer an image that is tougher than current photographic images. Furthermore, the use of paper in a photographic print which is used to provide opacity to prevent see through when looking at a print, can further result in a non-uniform surface which can lower its glossy appearance. There is a need for smoother photographic print material that provides opacity while not interfering with the gloss of the print. Typically when a polyester sheet is used for a base in photographic imaging, the base is clear and the resulting print material has poor opacity unless a pigmented filled polyester base is use. Such as base is very expensive and creates other problems. There remains a need to provide photographic base materials that improved opacity.
PROBLEM TO BE SOLVED BY THE INVENTION
There remains a need for a more effective imaging base to provide improved opacity over conventional bases.
SUMMARY OF THE INVENTION
It is an object of the invention to provide improved photographic papers.
It is another object to provide a more opaque photographic element.
It is another object to provide a photographic element that does not allow the transmission of light
It is an additional object to provide a photographic element that will hide dark or colored base layers.
These and other objects of the invention are accomplished by a photographic element comprising a laminated base wherein said comprises a voided polymer sheet having laminated thereto a biaxially oriented polyolefin sheet on the bottom of said polyester sheet and a biaxially oriented polyolefin sheet laminated to the top of said polymer sheet.
ADVANTAGEOUS EFFECT OF THE INVENTION
The invention provides an improved photographic support. It particularly provides an improved photographic papers that are more opaque and provides the use of color layers or indicia without show through.
DETAILED DESCRIPTION OF THE INVENTION
The invention has numerous advantages over prior practices in the art. The invention provides a photographic element that has much less tendency to curl when exposed to extremes of humidity. Further, the invention provides a photographic element that is much lower in cost as the criticalities of the formation of the polyethylene are removed. There is no need for the difficult and expensive casting and cooling in forming a surface on the polyethylene layer as the biaxially oriented polymer sheet of the invention provides a high quality surface for casting of photosensitive layers. The optical properties of the photographic elements in accordance with the invention are improved as the color materials may be concentrated at the surface of the biaxially oriented sheet for most effective use with little waste of the colorant materials. Photographic materials utilizing microvoided sheets and voided polyester base of the invention have improved resistance to tearing. The photographic materials of the invention are lower in cost to produce as the microvoided sheet may be scanned for quality prior to assembly into the photographic member. With present polyethylene layers the quality of the layer cannot be assessed until after complete formation of the base paper with the polyethylene waterproofing layer attached. Therefore, any defects result in expensive discard of expensive product. In addition the microvoided sheets provide opacity without the use of expensive pigments such as TiO
2
. In addition to obtaining opacity without pigmentation, there is a secondary benefit because microvoids do not add unwanted color to the image. The invention allows faster hardening of photographic paper emulsion, as water vapor is not transmitted from the emulsion through the biaxially oriented sheets.
The photographic elements of this invention are more scratch resistant as the oriented polymer sheet on the back of the photographic element resists scratching and other damage more readily than polyethylene. The photographic elements of this invention are balanced for stiffness in the machine and cross directions. A balanced stiffness of the photographic element is perceptually preferred over a photographic element that is predominantly stiff in one direction. The photographic elements of this invention utilize a low cost method for printing multiple color branding information of the back side of the image increasing the content of the information on the back side of the image. The voided polyester base used in the invention is smoother than prior art cellulose paper and substantially free of undesirable orange peel which interferes with the viewing of the image.
The photographic elements of this invention utilize an integral emulsion bonding layer that allows the emulsion to adhere to the support materials during manufacturing and wet processing of images. The microvoided sheets of the invention are laminated to the polyester base u
Aylward Peter T.
Bourdelais Robert P.
Camp Alphonse D.
Chen Vivian
Leipold Paul A.
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