Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2000-07-27
2002-07-23
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S157000, C430S160000, C430S161000, C430S162000, C430S273100, C430S288100, C430S302000
Reexamination Certificate
active
06423462
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming material which can be used as a planographic plate material, a color proof, a photoresist, or a color filter. More specifically, the present invention relates to a negative-type image forming material, suitably usable as a plate material for planography, which enables so-called direct plate formation in which a plate can be formed directly by scanning an infrared laser based on digital signals from a computer or the like.
2. Description of the Related Art
In recent years, high-output, compact solid-state lasers, semiconductor lasers, and gas lasers, which emit ultraviolet light, visible light, and infrared light having wavelengths ranging from 300 to 1200 nm, have become readily available. These lasers are very useful as a recording light source when a printing plate is formed directly based on digital data from a computer or the like.
Various studies of recording materials sensitive to these lasers have been made, and typical examples of photosensitive materials which can be recorded by an infrared laser beam having a wavelength of 760 nm or greater include the positive-type recording material described in U.S. Pat. No. 4,708,925, and the negative-type recording material which is crosslinkable by an acid catalyst and described in Japan Patent Application Laid-Open (JP-A) No. 8-276558.
As for recording materials sensitive to ultraviolet light or visible light lasers having wavelengths ranging from 300 to 700 nm, there are many negative-type recording materials and the like which are based on a radical polymerization such as those described in U.S. Pat. No. 2,850,445 and Japanese Patent Application Publication (JP-B) No. 44-20,189. Such materials utilizing a radical polymerization can achieve a high level of sensitivity. However, the sensitivity of a recording material based on a radical polymerization is generally significantly reduced due to the polymerization being inhibited by oxygen in the air. In order to prevent this problem, a layer impermeable to oxygen (i.e., a so-called overcoat layer represented by a polyvinyl alcohol layer or the like) is provided. However, there has been the concern that, when overcoat layer is provided, inhibition of polymerization by oxygen is prevented, thus resulting in deterioration of storage stability and fogging due to dark polymerization. In order to prevent this problem, normally a polymerization inhibitor is added so as to secure sensitivity and storage stability.
A material recordable by short-wave light or an electron beam having a wavelength of 300 nm or less, is important as a photoresist material in particular. In recent years the degree of integration in integrated circuits has increasingly risen, and even in the manufacture of semiconductor substrates such as ultra LSIs and the like, it has become necessary to form ultra-fine patterns having line widths of a half micron or less. In order to satisfy this need, wavelengths used in exposure apparatuses used for photolithography have become increasingly shorter. Far ultraviolet light and excimer light (XeCl, KrF, ArF, and the like) have come to be studied. Further, even ultra-fine patterning by an electron beam has come to be studied. In particular, electron beams are believed to be promising as light sources in next generation patterning technology.
A task common to all of these image forming materials has been how to intensify image ON-OFF in the portions irradiated and not irradiated, i.e., image portions and non-image portions, with the above-mentioned energies. In addition, there has been the problem that the adhesion of the portions irradiated with the above-mentioned energies to a support is weakened. In particular, when ultra-fine patterns are being written, the above-mentioned effects of raising sensitivity and increasing resolution are not sufficiently obtained if the adhesion of portions of the recording layer having very small surface areas to the support is weak. Since image forming materials satisfactorily free from these problems have not been obtained, a new technology different from conventional technologies has been sought.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a negative-type image forming material which solves the above-mentioned problems. In particular, the object of the present invention is to provide a negative-type image forming material which can be engraved directly from digital data from a computer or the like by using a solid-state laser or a semiconductor laser which emits an infrared ray, produces clear images with clearly discernible ON-OFF, and has excellent storage stability and a negative-type image forming material which ensures good adhesion to a support and has excellent storage stability.
In focusing their attention upon the layer structure of image forming materials, the present inventors discovered that the above-mentioned problems can be solved by forming on a support a recording layer which utilizes radical-polymerizability and has excellent sensitivity, and a recording layer crosslinkable by an acid, and therefore devised the present invention.
Accordingly, an image forming material comprising:
(a) an acid-crosslinkable layer containing a first compound that generates an acid when subjected to at least one of light and heat, and a second compound crosslinkable by said acid, the second compound having an alkali solubility which is lowered when crosslinked with said acid;
(b) a radical-polymerizable layer, containing one compound that generates a radical when subjected to at least one of light and heat and another compound capable of undergoing a radical polymerization and whose alkali solubility is lowered by said radical polymerization, and
(c) a support on which at least one of the layers is disposed, with the other layer being disposed on said at least one of the layers.
Preferably, the image forming material contains an infrared absorbent from the standpoint of raising sensitivity. The infrared absorbent may be contained in any one of the radical-polymerizable layer and the acid-crosslinkable layer or in both of them. Alternatively, the infrared absorbent may be contained in another layer provided in a position adjacent to the foregoing layers.
In the present invention, “provided with respective layers in an order” denotes that the radical-polymerizable layer and the oxygen-transmission controlling layer are provided on a support in the order listed in the passage. It should be noted, however, that the presence of other auxiliary layers, such as an intermediate layer, a protective layer, an undercoat layer, or the like, is not excluded by the description.
The mechanism resulting in the working of the present invention is not altogether clear. However, the mechanism is believed to be as follows. In the image forming material of the first aspect of the present invention, by first providing on a support an acid-crosslinkable layer and then using a radical-polymerizable layer on top of the acid-crosslinkable layer, a hardening of the film occurs due to radical polymerization whereby a raising of the sensitivity is achieved in the upper layers of the exposed portions. Next, an acid-catalyzed hardening having excellent adhesion occurs in the lower layers of the exposed portions. Further, because an acid crosslinkable layer which has innate high storage stability is used as the lower layer, the adhesiveness of the recording layer in the exposed portions can be improved while preserving the high sensitivity of the radical polymerization. In addition, the storage stability of the recording layer itself is also improved.
Therefore, when the image forming material of the present invention is used in a printing plate such as a planographic plate, problematic defects associated with recording layers of a radical polymerization type, such as insufficient adhesion due to volume contraction at the time of polymerization, and omissions of portions of an image (particularly small dots) at the time of printing, shorte
Burns Doane , Swecker, Mathis LLP
Chu John S.
Fuji Photo Film Co. , Ltd.
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