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
2000-12-19
2003-04-08
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
C430S278100, C430S271100, C430S280100, C430S284100, C430S285100, C430S287100, C430S302000, C430S306000, C430S325000, C430S905000, C430S910000, C430S916000, C430S925000, C430S926000, C430S944000, C430S945000
Reexamination Certificate
active
06544720
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a photosensitive composition which is useful for fine processing of e.g. lithographic printing plates, printed boards, LSI, TFT liquid crystal display devices, plasma display devices and TAB, and it further relates to an image-forming material, a photosensitive lithographic printing plate and an image-forming method. More particularly, it relates to a negative photosensitive resin composition which is useful for direct image-forming by laser scanning exposure based on digital signals of computers, etc. and which is suitable for exposure with an infrared laser such as a semiconductor laser or a solid state laser.
2. Discussion of Background
Lithographic technology employing a photosensitive resin has been widely used for fine processing of printed boards, LSI, TFT liquid crystal display devices, plasma display devices, TAB, etc. for image formation. For such a purpose, it is common to employ a method wherein image exposure is carried out through a mask, and a pattern is formed by utilizing the difference in solubility to a developer between an exposed portion and a non-exposed portion. If a laser beam is employed, a photosensitive resin can be directly scanned for image exposure based on digital information of a computer or the like, whereby not only the productivity but also the resolution, the positional precision, etc., can be improved. Accordingly, a direct image-forming method by a laser is being studied extensively.
As the laser beam, various light sources are known ranging from far ultraviolet rays to microwaves. However, a laser beam useful for lithography from the viewpoint of the laser power, stability, costs, sensitizing ability, etc., is preferably one which emits visible light to infrared light, such as an Ar ion laser, a YAG laser, a helium neon laser or a semiconductor laser. Accordingly, various compositions having photosensitivities within a range of from visible light to infrared light, are being studied.
Among them, a positive photosensitive composition utilizing a phase change of a novolak resin (JP-A-9-43847) is known as a composition which is selectively sensitive to infrared light and has a safe light property against white light, and, as a composition utilizing a thermal reaction by a photo-thermal conversion substance, one utilizing crosslinking of a block isocyanate (JP-A-6-1088, and JP-A-9-43845) or one utilizing a phenolic crosslinking agent (JP-A-8-276558) is known. However, such compositions have had a problem from the viewpoint of the sensitivity and stability.
Further, JP-A-62-143044 and JP-A-62-150242 disclose photosensitive compositions comprising an ethylenic monomer, an organic boron complex and a cation dye. However, the photosensitive compositions disclosed in these publications are sensitive to light in a visible to near infrared region and thus have had a problem in handling under white light.
On the other hand, JP-A-6-175564 discloses a hologram recording material comprising a polymer compound which is a (co)polymer of a vinyl monomer, a compound having at least one ethylenically unsaturated bond, a porphyrazine derivative including a phthalocyanine compound and a sulfonium organic boron complex, and specifically describes an example wherein hologram recording was carried out with a light having a wavelength of from 633 to 647 nm.
SUMMARY OF THE INVENTION
Under these circumstances, it is an object of the present invention to provide a photosensitive resin composition for direct image forming by a laser, which 1) has a high sensitivity to a laser beam emitting infrared light, 2) can easily be handled under white light without requiring any special environment such as a red light lamp, 3) can be developed with an aqueous alkali solution, and 4) is excellent in the stability of the photosensitive liquid or in the stability of an image-forming material having a layer made of such a photosensitive composition, and to provide an image-forming material and an image-forming method.
Another object of the present invention is to provide a photosensitive lithographic printing plate excellent in the printing properties such as the adhesion and the chemical resistance.
As a result of an extensive study, the present inventors have found that a combination of a photopolymerization initiator and a phthalocyanine compound showing the maximum absorption at a specific wavelength exhibits a photosensitivity which is selectively high only to infrared light and thus can be safely handled under white light.
Further, it has been found that when stored as a photosensitive liquid, such a combination is stable without any particular change such as precipitation and can be developed with an aqueous alkali solution to form an image.
Namely, the present invention provides a photosensitive composition comprising (a) an ethylenically unsaturated double bond-containing compound, (b) a sensitizing dye and (c) a photopolymerization initiator, wherein the sensitizing dye is a phthalocyanine compound showing the maximum absorption within a range of from 750 to 1,200 nm.
Further, the present invention provides an image-forming material comprising a substrate and a photosensitive layer made of the photosensitive composition, formed on the substrate.
Still further, the present invention provides an image-forming method which comprises subjecting the image-forming material to exposure with an infrared laser having a wavelength within a range of from 780 to 1,200 nm, followed by development with an alkali developer to remove unexposed portions.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, the preferred embodiments of the present invention will be described in detail.
(a) Ethylenically Unsaturated Double Bond-Containing Compound (Hereinafter Referred to as “Ethylenically Unsaturated Compound”)
The ethylenically unsaturated compound may be a compound having at least one polymerizable unsaturated double bond in its molecule. Various known unsaturated compounds may be used. Among them, particularly preferred is a low molecular weight compound having at least two double bonds in the molecule, a so-called acryl monomer, from the viewpoint of the crosslinking efficiency, change in solubility, etc. The acryl monomer will be described in detail hereinafter, but, from the viewpoint of the sensitivity, one having at least four double bonds in its molecule, is particularly preferred. In the present invention, the acryl monomer includes a methacryl monomer. The molecular weight of the low molecular weight compound is usually at most 2,000, preferably at most 1,000. The lower limit is not particularly limited, but it is usually at least 20.
The acryl monomer may, for example, be an ester acrylate compound having an unsaturated carboxylic acid condensed with an aliphatic alcohol or with an aromatic hydroxyl compound, an epoxy acrylate compound having an unsaturated carboxylic acid added to an aliphatic or aromatic epoxy compound, a urethane acrylate compound having an unsaturated hydroxy compound added to an isocyanate compound, an acryloyloxyalkyl group-containing amine compound, or an acryloyloxyalkyl group-containing phosphate compound. However, the acryl monomer is not limited to such specific examples.
The ester acrylate compound may, for example, be 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, glycerol methacrylate(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane ethyleneoxide-added tri(meth)acrylate, glycerolpropylene oxide-added tri(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexaacrylate, so
Takasaki Ryuichiro
Urano Toshiyuki
Baxter Janet
Lu Sin J.
Mitsubishi Chemical Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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