Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making printing plates
Reexamination Certificate
2000-09-26
2002-07-09
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making printing plates
C430S271100
Reexamination Certificate
active
06416932
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to pattern formation and particularly, although not exclusively, relates to pattern-forming methods, precursors for use in such methods and novel polymeric substances and formulations for use in such methods. Preferred embodiments relate to the preparation of printing members, especially planographic (eg. lithographic) printing members.
2. Background Information
The art of lithographic printing is based on the immiscibility of ink, generally an oily formulation, and water, wherein in the traditional method the ink is preferentially retained by the image or pattern area and the water or fountain solution is preferentially retained by the non-image or non-pattern area. When a suitably prepared surface is moistened with water and an ink is then applied, the background or non-image area retains the water whilst the image area accepts ink and repels the water. The ink on the image area is then transferred to the surface of a material upon which the image is to be reproduced, such as paper, cloth and the like. Commonly the ink is transferred to an intermediate material called the blanket which in turn transfers the ink to the surface of the material upon which the image is to be reproduced.
New types of “waterless” lithographic printing employ only an oily ink material and preferentially ink-accepting image areas and ink-repelling non-image areas on the printing form.
There are a number of different types of waterless lithographic printing form precursors (by which we mean a coated printing form prior to exposure and optional development). A first type may comprise an oleophilic base having thereon a radiation sensitive coating which when imagewise exposed to radiation of a suitable wavelength hardens in the exposed areas. On development, the non-exposed areas of the coating are removed leaving the image. A second type may comprise an oleophobic base having thereon a radiation sensitive coating which after imagewise exposure has exposed areas which are more soluble in a developer than non-exposed areas. In this case, therefore, non-exposed areas define the image and exposed areas are removed. In both the first and second types, the coating which defines the image is non-ink-accepting (oleophobic) and the base is ink-accepting (oleophilic). In other arrangements, the base may be oleophobic and the coating may be oleophilic.
In a third type of printing form, exposed areas of a radiation sensitive coating on a support are rendered more ink receptive (oleophilic) than non-exposed areas by the exposure process alone (i.e. without a development step) and this differentiation is sufficient to enable the form to be used in printing. In another example of the third type, exposed and non-exposed areas may be oleophobic and oleophilic respectively.
The photoresists used in pattern forming methods for electronic parts such as printed circuits may comprise radiation sensitive coatings of either the first or second types described above. After exposure to radiation and development, the remaining coating acts as a mask for forming the patterns onto the underlying electronic elements—for example by etching an underlying copper foil. Due to the high resolution demands and the requirements of high resistance to etching techniques, compositions of the second type described above are widely used. In particular, there have in the main been used alkali developable compositions of alkali-soluble novolak resins as disclosed in J. C. Streiter, Kodak Microelectronics Seminar Proceedings, 1979, p. 116. The primary active component of such compositions, both in the context of lithographic printing forms and electronic parts, is a naphthoquinonediazide (NQD) derivative.
The types of electronic parts whose manufacture may use a photo resist include printed wiring boards (PWBs), thick- and thin-film circuits, comprising passive elements such as resistors, capacitors and inductors; multichip devices (MDCs); and integrated circuits (ICs). These are all classified as printed circuits.
It is an object of the present invention to address problems associated with pattern formation.
SUMMARY OF THE INVENTION
This invention is directed to a method of producing a member comprising a predetermined pattern on a substrate. The method comprises: (a) providing a precursor comprising a substrate on which is provided a coating composition which includes a functionalized polymeric substance having functional groups Q thereon wherein said functionalized polymeric substance is heat sensitive and said functional groups Q thereon cause said polymeric substance to have a reduced adhesive interaction with ink for use in waterless lithographic printing compared to said polymeric substance in the absence of said groups Q, and (b) causing the pattern-wise application of heat to said coating composition and optional development thereby to define ink-accepting areas in heat exposed areas and non-ink-accepting areas in non-exposed areas. In a preferred embodiment, the member is a waterless printing member. The functionalized polymeric substance is preferably obtained from the reaction product of an esterification reaction between a polymeric substance having functional groups A thereon and a compound BQ wherein groups A and B react to form a ester group.
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention, there is provided a method of producing a member comprising a predetermined pattern on a substrate, the method using a precursor comprising said substrate on which is provided a coating composition which includes a polymeric substance having functional groups Q thereon (hereinafter “said functionalized polymeric substance”) wherein said functionalized polymeric substance is heat sensitive and said functional groups Q thereon cause said polymeric substance to have a reduced adhesive interaction with ink for use in waterless lithographic printing compared to said polymeric substance in the absence of said groups Q, the method including the step of causing the pattern-wise application of heat to said coating composition and optional development thereby to define ink-accepting areas in heat exposed areas and non-ink-accepting areas in non-exposed areas.
Preferably, said functional groups Q on said polymeric substance cause said functionalized polymeric substance to be heat-sensitive. Said polymeric substance (in the absence of said groups Q) may not be heat sensitive.
A preferred embodiment of the present invention provides a method of producing a waterless printing member, the method using a precursor comprising a substance on which is provided a coating composition which includes a polymeric substance having functional groups Q thereon (hereinafter “said functionalized polymeric substance”) wherein said functionalized polymeric substance is heat sensitive and said functional groups Q thereon cause said functionalized substance to have a reduced adhesive interaction with ink for use in waterless lithographic printing compared to said polymeric substance in the absence of said groups Q, the method including the step of causing the pattern-wise application of heat to said coating composition and optional development thereby to define ink-accepting areas in heat exposed areas and non-ink-accepting areas in non-exposed areas.
Said functionalized polymeric substance preferably has the property that it is non-ink-accepting (or adhesive) to ink for use in waterless lithographic printing prior to application of heat and ink-accepting (or adhesive) to ink for use in waterless lithographic printing after application of heat.
Said functionalized polymeric substance preferably has the property that it is developer insoluble prior to the delivery of heat and developer soluble thereafter.
Preferably, said functional groups Q on said polymeric substance cause said functionalized polymeric substance to have the property that it is developer insoluble prior to the delivery of heat and developer soluble thereafter. Preferably, said polymeric subs
McCullough Christopher David
Ray Kevin Barry
Baker & Botts L.L.P.
Baxter Janet
Gilmore Barbara
Kodak Polychrome Graphics LLC
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