Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Structurally defined
Reexamination Certificate
2002-12-20
2004-03-09
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Structurally defined
C430S533000, C428S315500, C428S316600, C428S318400, C428S319300
Reexamination Certificate
active
06703193
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to microbead and immiscible polymer voided films for use in imaging media.
BACKGROUND OF THE INVENTION
Recording elements or media typically comprise a substrate or a support material optionally having on at least one surface thereof an image-forming layer. The elements include those intended for reflection viewing, which usually have an opaque support, and those intended for viewing by transmitted light, which usually have a transparent support.
While a wide variety of different types of image-recording elements have been proposed, there are many unsolved problems in the art and many deficiencies in the known products which have severely limited their commercial usefulness. These deficiencies vary with the type of image recording element.
Various arrangements have been proposed to improve the quality of silver halide imaging medias as well. In the case of display medias it has been described in U.S. Pat. Nos. 6,093,521 and 6,355,404 how voided polyester layers in the substrate of a display designed to have high image quality when viewed either in reflection or transmission modes are very effective. The preferred means by which to void the polyester in the voided layer of the displays described in U.S. Pat. Nos. 6,093,521 and 6,355,404 is to use crosslinked microbeads as void initiators. Although these microbeads perform very well in terms of light diffusion and image quality, they require a complex process to manufacture. Also, a pre-mixing step, known as compounding, is used to introduce the microbeads into the polyester prior to manufacturing the substrate. This results in a high cost to manufacture display medias using substrates comprising only microbeads as the void initiators in the voided polyester layer.
The use of immiscible polymer particles as a void initiator has been described in U.S. Pat. No. 4,187,113. This means of voiding is very robust and results in a low cost means to void polyester. The immiscible polymer may be added simultaneously with manufacturing the substrate. However, the use of such a voided polyester layer in the display medias of U.S. Pat. Nos. 6,093,521 and 6,355,404 results in very poor image sharpness due to the relatively large voids which result when voiding with immiscible polymers in this manner. Thus, it can be seen that a need still exists in the art for the provision of a silver halide image recording element for displays with both high image quality and low manufacturing cost.
The problem to be solved by the present invention is to formulate a silver halide display imaging media with a voided polyester diffuse layer which provides both high image quality and low manufacturing cost.
SUMMARY OF THE INVENTION
The present invention relates to an image recording element comprising an image recording element comprising a microvoided layer comprising a continuous phase polyester matrix having dispersed therein crosslinked organic microbeads and non-crosslinked polymer particles that are immiscible with the polyester matrix of the microvoided layer.
ADVANTAGEOUS EFFECT OF THE INVENTION
The present invention includes several advantages, not all of which may be incorporated in any one embodiment. In one advantage, the invention provides improved imaging medias. In another advantage, the invention provides improved image sharpness and lower manufacturing and raw material cost compared to prior art voided polyester substrate silver halide imaging medias.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to image recording elements comprising a voided layer of polyester matrix. The recording element may additionally comprise an image recording layer. The voided polyester layer of the element comprises a continuous phase polyester matrix having dispersed therein crosslinked organic microbeads and non-crosslinked polymer particles. The non-crosslinked polymer particles are immiscible with the polyester matrix to form a microvoided layer that can be produced at a much lower manufacturing cost than that using crosslinked microbeads.
In the prior art, microvoided polyester matrix layers have been formed by using either microbeads or non-crosslinked polymer particles that are immiscible with the polyester matrix. In the case of silver halide display medias when only microbeads are used, very high image sharpness is attained. However, there is a disadvantage of high manufacturing cost, since the beads require a complex process to manufacture and are therefore expensive and are used at high usage levels. In addition, a pre-mixing step, known as compounding, is used to introduce the microbeads into the polyester matrix prior to manufacturing the substrate. This results in a high cost to manufacture display medias using substrates comprising only microbeads as the void initiators in the voided polyester layer, since the high usage levels adds time and effort to the manufacturing process. Thus, although microbeads produce an element with good quality with respect to sharpness, they are very expensive for use in imaging media due to their high raw material cost, and time and effort consuming when used in the imaging media manufacturing process
If only non-crosslinked polymer particles that are immiscible with the polyester matrix are used in the microvoided layer of a silver halide display media the raw material and manufacturing cost is low, as a compounding step is not required, but the image sharpness is very poor due to the relatively large voids that result. Thus although the use of immiscible polymer particles as voiding agents in imaging media is attractive from a cost standpoint, the quality with respect to sharpness is prohibitively inferior.
It has been unexpectedly discovered that by mixing both the crosslinked organic microbeads and the non-crosslinked polymer particles that are immiscible with polyester into the polyester matrix of the microvoided layer the deficiencies of the void initiators when used singularly are synergistically overcome, especially with respect to image quality and manufacturability. The combination of crosslinked organic beads and non-crosslinked polymer particles immiscible in a polyester matrix enjoys the quality, with respect to sharpness of microbead-voided media, without the expected degradation associated with the addition of a material with poor sharpness quality, with significant cost reductions and manufacturing time and effort reductions resulting from the need to use less costly raw material which in turn lowers the time and effort needed to compound microbeads with matrix polymer.
The terms as used herein, “top”, “upper”, and “face” mean the side or toward the side of the element receiving an image. The terms “bottom”, “lower side”, and “back” mean the side opposite that which receives an image.
The term as used herein, “transparent” means the ability to pass radiation without significant deviation or absorption. For this invention, “transparent” material is defined as a material that has a spectral transmission greater than 20%. For a photographic element, spectral transmission is the ratio of the transmitted power to the incident power and is expressed as a percentage as follows; T
RGB
=10
D
*100 where D is the average of the red, green and blue Status A transmission density response measured by an X-Rite model 310 (or comparable) photographic transmission densitometer. The term as used herein, “duplitized” element means elements with light sensitive silver halide coating on the top side and the bottom side of the imaging support.
The term voids or microvoids means pores formed in an oriented polymeric film during stretching as the result of a void-initiating particle. In the present invention, these pores are initiated by either microcrosslinked organic microbeads or non-crosslinked polymer particles that are immiscible with the polyester matrix. The term microbead means synthesized polymeric spheres which, in the present invention, are crosslinked.
The continuous phase polyester matrix of the microvoided layer comprises any polyester and
Best, Jr. Kenneth W.
Laney Thomas M.
Blank Lynne M.
Eastman Kodak Company
Schilling Richard L.
LandOfFree
Microbead and immiscible polymer voided polyester for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Microbead and immiscible polymer voided polyester for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microbead and immiscible polymer voided polyester for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3268919