Radiation imagery chemistry: process – composition – or product th – Post imaging processing – Including post developing step
Reexamination Certificate
2001-10-29
2003-07-08
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Post imaging processing
Including post developing step
C430S104000, C430S201000, C430S496000, C430S527000, C430S533000, C430S536000, C430S538000, C347S105000, C428S481000, C428S511000, C428S512000, C428S537500
Reexamination Certificate
active
06589720
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to reflective imaging materials. In a preferred form it relates to laminated base materials for imaging elements.
BACKGROUND OF THE INVENTION
In the formation of imaging paper it is known that the base paper has applied thereto a layer of polyolefin resin, typically polyethylene. This layer serves to provide waterproofing to the paper and provides a smooth surface on which the photosensitive layers are formed. The formation of the smooth surface is controlled by both the roughness of the chill roll where the polyolefin resin is cast, the amount of resin applied to the base paper surface, and the roughness of the base paper. Since the addition of polyolefin resin to improve the surface adds significant cost to the product it would be desirable if a smoother base paper could be made to improve the gloss of imaging paper. Sheet properties such as smoothness may be improved through the addition of inorganic particulate filler materials to paper making furnishes.
It has been proposed in U.S. Pat. No. 5,866,282 (Bourdelais et al.), to utilize a composite support material with laminated biaxially oriented polyolefin sheets as a imaging imaging material. In U.S. Pat. No. 5,866,282 , biaxially oriented polyolefin sheets are extrusion laminated to cellulose paper to create a support for silver halide imaging layers. The biaxially oriented sheets described in U.S. Pat. No. 5,866,282 have a microvoided layer in combination with coextruded layers that contain white pigments such as TiO
2
above and below the microvoided layer. The composite imaging support structure described in U.S. Pat. No. 5,866,282 has been found to be more durable, sharper and brighter than prior art imaging paper imaging supports that use cast melt extruded polyethylene layers coated on cellulose paper. While the voided polymer layer does provide a significant improvement to image sharpness and brightness, the voided polymer is susceptible to cracking during bending of the imaging element.
It has been proposed in U.S. Pat. No. 6,040,036 to utilize a microvoided layer of sufficient strength to reduce cracking during bending of the imaging element. While the imaging element disclosed in U.S. Pat. No. 6,040,036 does reduce cracking and retains the beneficial properties of a voided layer, the imaging element is still susceptible to cracking. Cracking of the image layer reduces the commercial value of the image and particularly for labels that are wrapped around packages, reduces the perceived quality of the package contents.
The addition of inorganic particulate fillers such as clay, TiO
2
, calcium carbonate and talc, improves sheet properties because the particles fill in the void spaces within the fiber mat resulting in a denser, brighter, smoother, and more opaque sheet. In some instances, paper can also be made cheaper because the filler used is less expensive than cellulose fiber.
The substitution of fiber with filler in the sheet is, however, limited by the resultant reduction in strength, density, and sizing properties. As the proportion of filler is increased, fiber-to-fiber bonding is disrupted resulting in a reduction in sheet strength and stiffness properties. Due to the filling of sheet voids with increasing filler addition, sheet density is increased. The increased hydrophilicity of inorganic fillers over chemically-treated (sized) paper-making fibers also results in a reduction in sizing properties of the coated paper. All of the above undesirable changes limit the use of filler materials in various applications, particularly in imaging coated paper, where even a small change in any of the above properties can seriously affect efficacy of the resulting image as a photograph. In addition to the above, the choice of filler is also limited because of it's impact on sheet properties or because of it's undesired presence in processing steps. For example, the filler material should not have photographic activity or degrade the performance of the imaging element in which it is utilized.
In EP 952483, coated paper in combination with an extruded polyethylene layer is disclosed as a method for reducing coating craters at lamination speeds greater than 300 meters/min. as air is trapped between the paper and the polyethylene coating. Coated paper with a roughness average of less than 1.0 micrometers is disclosed and is shown to reduce coating craters. While a coated paper does reduce coating craters caused by trapped air during the extrusion coating of the paper, coated paper is not required for lamination of high modulus polymer sheets as lamination does not suffer from trapped air at high speeds. Further, it has been shown that coated paper with a surface roughness greater than 1.0 micrometers provides a high quality, glossy image. Finally, the paper coating formulations in EP 952483 have been shown to provide an unacceptable bond between the coated paper and high modulus polymer sheets during extrusion lamination.
Roll feed, glue applied labels are typically utilized to wrap packages and the label is adhered to the package using glue applied to the label or the package. Prior art roll feed, glue applied label comprise ink printed oriented polymer sheets that are over laminated with a polymer sheet after printing. The base materials typically utilized for the roll feed glue applied labels are not stiff enough for efficient transport through photographic printers and processors. Further, there is a continuing need to improve the quality of the images on roll feed, glue applied labels.
PROBLEM TO BE SOLVED BY THE INVENTION
There remains a need for an improved imaging paper to provide improved image gloss, a stronger imaging element, less image curl over a wide range of relative humidity, higher image sharpness, and improved image whiteness while providing resistance to image creasing.
SUMMARY OF THE INVENTION
It is an object of the invention to provide improved imaging papers.
It is another object to provide photosensitive images having improved surface smoothness.
It is a further object to provide a imaging paper with improved curl properties.
It is another object to provide tear resistant imaging paper.
It is a further object to provide a imaging paper with resistance to creasing caused by consumer handling.
It is another object to provide an integral imaging emulsion adhesion layer.
It is further object to provide a lamination bonding layer that resists delamination of the support.
These and other objects of the invention are accomplished by an imaging element comprising a coated paper base, a lower biaxially oriented sheet, and an upper biaxially oriented sheet.
ADVANTAGEOUS EFFECT OF THE INVENTION
The invention provides an improved base for casting of photosensitive layers. It particularly provides improved base for color imaging materials that have greater resistance to curl, an improved image, tear resistance, and resistance to image creasing.
DETAILED DESCRIPTION OF THE INVENTION
The invention has numerous advantages over prior practices in the art. The invention provides a imaging element that has much less tendency to curl when exposed to extremes of humidity. Further, the invention provides a imaging paper 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 imaging 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. Imaging materials utilizing oriented polymer sheets of the invention have improved resistance to tearing and creasing compared to prior art microvoided polymer sheets. The imaging materials of the invention are lower in cost to produce, as the polymer sheet may be s
Aylward Peter T.
Bourdelais Robert P.
Mruk Geoffrey
Eastman Kodak Company
Leipold Paul A.
Schilling Richard L.
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