Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2001-12-03
2003-12-30
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S281100, C430S495100, C430S523000, C101S453000
Reexamination Certificate
active
06670096
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a novel base material for a lithographic printing plate and a novel lithographic printing plate using the same. More particularly, it relates to a base material suitable for using in both positive working and negative working lithographic printing plates excellent in sensitivity and stain-preventing property, and to a lithographic printing plate suitable for imaging with a laser beam.
BACKGROUND OF THE INVENTION
As a hydrophilic support used in a lithographic printing plate, an anodized aluminum support and a support obtained by subjecting an anodized aluminum support to a treatment with an undercoating agent, such as silicate, polyvinyl phosphonic acid (described in JP-A-7-1853, the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and polyvinyl benzoic acid, for increasing the hydrophilicity have been employed. Investigations of hydrophilic supports using aluminum support have been earnestly carried out. JP-A-59-101651 discloses a technique using a polymer having a sulfonic acid group as an undercoating layer of a photosensitive layer.
With respect to a hydrophilic layer for the case where a flexible support, such as PET (polyethylene terephthalate) and cellulose acetate, is used instead of a metallic support like aluminum, such techniques have been known as a swelling hydrophilic layer comprising a hydrophilic polymer and a hydrophobic polymer described in JP-A-8-292558, a PET support having a microporous hydrophilic crosslinked silicate surface described in EP 0,709,228, and a hydrophilic layer containing a hydrophilic polymer and being hardened with tetraalkyl orthosilicate described in JP-A-8-272087 and JP-A-8-507727.
These hydrophilic layers provide a lithographic printing plate that provides printed matter without stain in the initial stage of printing. From the practical standpoint, however, a lithographic printing plate that has high sensitivity and excellent printing durability under severer printing conditions and can provide printed matter without stain has been demanded.
As a photosensitive lithographic printing plate, a so-called PS plate has been widely used, which has such a constitution that a lipophilic photosensitive resin layer is provided on a hydrophilic support. In a plate-making process thereof, it is usual that after mask exposure (plane exposure) through a lith film, a non-image part is dissolved and removed to obtain a printing plate.
In recent years, digitalization technologies have been widely spread, by which image information is electronically processed, accumulated and output using computers. Various kinds of new image output methods have been practically used corresponding to the digitalization technologies. As a result, a computer-to-plate (CTP) technique is demanded, in which a printing plate is directly produced by scanning with light having high directivity, such as a laser beam, according to image information without using a lith film, and it is an important technical task to obtain a photosensitive lithographic printing plate adapted to such a technique.
As an example of the photosensitive lithographic printing plate capable of being subjected to scanning exposure, such a product is proposed and commercially available that has a hydrophilic support having thereon a lipophilic photosensitive resin layer (hereinafter, sometimes referred to as a photosensitive layer) containing a photosensitive compound capable of generating an active species, such as a radical or a Bronsted acid, upon laser exposure. The photosensitive lithographic printing plate is subjected to laser scanning according to digital information to form an active species, and physical or chemical change is induced in the photosensitive layer owing to the action of the active species to insolubilize or solubilize the photosensitive layer. The printing plate is then subjected to a developing treatment to obtain a negative working or positive working lithographic printing plate.
In particular, a negative working photosensitive lithographic printing plate, which has a hydrophilic support having provided thereon a photopolymerizable photosensitive layer containing a photopolymerization initiator excellent in photosensitivity, an addition polymerizable ethylenically unsaturated compound and a polymer binder soluble in an alkali developing solution, and if desired, a protective layer having a function of blocking oxygen, is expected to be a printing plate having the desired printing performance owing to such advantages as excellent productivity, easiness in developing treatment and good resolution and thickening property. However, further improvements of printing performance, particularly improvements in sensitivity and printing durability have been demanded.
SUMMARY OF THE INVENTION
An object of the invention is to solve the problems accompanied with conventional techniques and specifically, to provide a base material for a lithographic printing plate that has high sensitivity, is excellent in printing durability under severe printing conditions, causes no stain on resulting printed matter, and has high hydrophilicity on the surface thereof.
Another object of the invention is to provide a photosensitive lithographic printing plate that provides sufficient printing durability under an exposure condition of small irradiation energy per unit area, and has high sensitivity, and particularly to provide a photosensitive lithographic printing plate suitable for imaging with a laser beam.
A further object of the invention is to provide a photosensitive lithographic printing plate that is suitable for plate-making by direct image-formation with a laser beam having a wavelength of from 300 to 1,200 nm, and exhibits high printing durability in comparison to conventional lithographic printing plates.
These objects of the invention can be attained by the following constitutions:
(1) A base material for a lithographic printing plate comprising a support, a hydrophilic organic polymer compound that is chemically bonded to a surface of the support, and an ionic compound that is ionically bonded to the hydrophilic organic polymer compound.
(2) The base material for a lithographic printing plate as described in item (1), wherein the hydrophilic organic polymer compound is a hydrophilic chain polymer that is chemically bonded to the surface of the support at a terminal of the chain.
(3) The base material for a lithographic printing plate as described in item (1), wherein the hydrophilic organic polymer compound is a graft polymer having a main chain that is chemically bonded to the surface of the support and a hydrophilic polymer side chain.
(4) The base material for a lithographic printing plate as described in item (1), wherein the ionic compound is a cationic compound.
(5) The base material for a lithographic printing plate as described in item (1), wherein the ionic compound is an anionic compound.
(6) The base material for a lithographic printing plate as described in item (1), wherein the ionic compound is an infrared absorbing dye.
(7) The base material for a lithographic printing plate as described in item (1), wherein the ionic compound is a photopolymerization initiator.
(8) A lithographic printing plate comprising: a base material which comprises a support, a hydrophilic organic polymer compound that is chemically bonded to a surface of the support, and an ionic compound that is ionically bonded to the hydrophilic organic polymer compound; and an image forming layer whose water-solubility changes with heat.
(9) A lithographic printing plate comprising: a base material which comprises a support, a hydrophilic organic polymer compound that is chemically bonded to a surface of the support, and an ionic compound that is ionically bonded to the hydrophilic organic polymer compound; and an image forming layer whose alkali-solubility changes with heat.
(10) A lithographic printing plate comprising: a base material which comprises a support, a hydrophilic organic polymer compound that is chemically bonde
Kawamura Koichi
Sorori Tadahiro
Takahashi Miki
Yamasaki Sumiaki
Baxter Janet
Burns Doane , Swecker, Mathis LLP
Fuji Photo Film Co. , Ltd.
Gilliam Barbara
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