USOO7279263B2

(12) United States Patent (10) Patent No.: US 7,279.263 B2 G00din (45) Date of Patent: Oct. 9, 2007

(54) DUAL-WAVELENGTH POSITIVE-WORKING 6,238,838 B1 5, 2001 Gaschler et al. RADATION-SENSITIVE ELEMENTS 6.255,033 B1 7/2001 Levanon et al. 6,280,899 B1 8, 2001 Parsons et al. (75) Inventor: Jonathan W. Goodin, Tyler, TX (US) 6,326,122 B1 12/2001 Nagasaka et al. 6,331,375 B1 12/2001 Kawamura et al. 6,346,365 B1 2/2002 Kawauchi et al. (73) Assignee: Kodak Graphic Communications 6.410,203 B1 6/2002 Nakamura Canada Company, Burnaby, British 6.410,207 B1 6/2002 Nagasaka et al. Columbia (CA) 6,444,393 B2 9/2002 Nakamura et al. 6,472,119 B1 10/2002 Verschueren et al. (*) Notice: Subject to any disclaimer, the term of this 6,485,890 B2 11/2002 Parsons et al. patent is extended or adjusted under 35 6,506.536 B2 1/2003 Pappas et al. U.S.C. 154(b) by 0 days. 6,537,735 B1 3/2003 McCullough et al. (21) Appl. No.: 11/157.204 FOREIGN PATENT DOCUMENTS EP O 913 253 B1 5, 1999 (22) Filed: Jun. 20, 2005 WO WO O3,O791.13 9, 2003 WO WO 2004/020484 3, 2004 (65) Prior Publication Data WO WO 2004/081.662 9, 2004 US 2005/0287.468 A1 Dec. 29, 2005 * cited by examiner Related U.S. Application Data Primary Examiner John S. Chu (60) Provisional application No. 60/582,085, filed on Jun. (74) Attorney, Agent, or Firm—J. Lanny Tucker 24, 2004. (57) ABSTRACT (51) Int. Cl. A positive-working radiation-sensitive composition for use GO3F 7/02 (2006.01) with a radiation source comprises one or more polymers GO3F 7/023 (2006.01) capable of being eluted in an alkaline aqueous Solution and GO3F 7/30 (2006.01) a development-enhancing compound. The invention pro (52) U.S. Cl...... 430/157:43.0/176; 430/191; vides a positive-working photosensitive composition of 430/192: 430/193; 430/302 good sensitivity for use with one or both of ultra-violet (58) Field of Classification Search ...... 430/191, radiation and an infrared laser radiation Source. The com 430/192, 193,270.1, 326, 157, 176,302 position is stable in its state before exposure and has an See application file for complete search history. excellent handling property. The sensitivity of a radiation (56) References Cited sensitive coating based on the composition of this invention is increased without compromising the handling character U.S. PATENT DOCUMENTS istics. Radiation-sensitive elements based on the composi tion of the invention have good development latitude. A 5,219,699 A * 6/1993 Walls et al...... 430,156 positive-working lithographic printing precursor is based on

5,262,270 A * 11/1993 Walls ...... 430,156 5,316,892 A * 5/1994 Walls et al...... 430.309 the radiation-sensitive composition coated on a hydrophilic 5,534,381 A * 7/1996 Ali et al...... 430,156 Surface. The precursor is developable using an alkaline 5,646,218 A 7/1997 Lynch et al. aqueous solution, and may be used with a radiation source 5,840,467 A 11/1998 Kitatani et al. in lithographic applications, such as conventional imaging 6,060,217 A 5/2000 Nguyen et al. systems, computer-to-plate systems or other direct imaging 6,060,218 A 5, 2000 Van Damme et al. applications. The precursor is stable in its state before 6,060,222 A * 5/2000 West et al...... 430,326 6,074,802 A 6, 2000 Murata et al. exposure and has an excellent handling property. 6,110,646 A 8, 2000 Urano et al. 6,117,613 A 9/2000 Kawauchi et al. 32 Claims, No Drawings US 7,279.263 B2 1. 2 DUAL-WAVELENGTH POSITIVE-WORKING lasers having a luminous band from near infrared wave RADATION-SENSITIVE ELEMENTS lengths to infrared wavelengths and which are Small-sized and have a high energy output have become commercially CROSS-REFERENCE TO RELATED available. These lasers are very useful as exposure light APPLICATION Sources for exposure when LDI is required. Thermally sensitive imaging elements are classified as This application claims the benefit of provisional appli compositions that undergo chemical transformation(s) in cation No. 60/582,085, filed Jun. 24, 2004. response to exposure to, and absorption of Suitable amounts of heat energy. The nature of thermally induced chemical FIELD OF INVENTION 10 transformation may be to ablate the composition, or to change the solubility of the composition in a particular The invention pertains to the field of radiation-sensitive developer, or to change tackiness of the Surface, or to change compositions and, in particular, to their use in imaging the hydrophilicity or the hydrophobicity of the surface of the elements. thermally sensitive layer. As such, selective heat exposure of 15 predetermined areas (imagewise distribution of heat energy) BACKGROUND OF INVENTION of a film or layer formed of a thermally-sensitive composi tion has the capability of directly or indirectly producing a Lithographic processes involve establishing image (print Suitably imaged pattern which can serve as a resist pattern in ing) and non-image (non-printing) areas on a Substrate, printed circuit board fabrication, or in production of litho Substantially on a common plane. When Such processes are graphic printing plates. Positive working systems based on used in printing industries, non-image areas and image areas novolak-diazoquinone resins are an imaging mainstay of the are arranged to have different affinities for printing ink. For computer chip industry (see, e.g. R. R. Dammel, “Diaz example, non-image areas may be generally hydrophilic or onaphthoguinone-based Resists”. Tutorial text No. 11, SPIE oleophobic and image areas may be oleophilic. Press, Bellingham. WA, 993). The types of electronic parts whose manufacture may use 25 Compositions of light sensitive novolak-diazoquinone a radiation-sensitive composition include printed wiring resins are also widely used in printing plate fabrication. The circuit boards, thick-and thin-film circuits, comprising pas light sensitive diazonaphthoquinone derivatives (DNQ) sive elements such as resistors, capacitors and inductors; added to or reacted with novolak resins (a phenol-formal multichip devices; integrated circuits; and active semicon dehyde condensation polymer) slow down the elution of the ductor devices. The electronic parts may suitably comprise 30 resin. A revised molecular mechanism of novolak-DNQ conductors, for example copper board; semiconductors, for imaging materials has been Suggested (A. Reiser, Journal of example silicon, or germanium or Group III-V compound Imaging Science and Technology, Volume 42, Number 1, materials; and insulators, for example silica, as a surface January/February 1998, pp. 15-22). This text teaches that the layer with silicon beneath, with the silica being selectively basic features of the imaging phenomena in novolak-diaz etched away to expose portions of the silicon beneath. In 35 onaphthoguinone compositions is the observed inhibition of relation to masks, a required pattern may be formed in the dissolution of the resin, based on the formation of phenolic coating on the mask precursor, for example a plastics film, strings by the interaction of the strong hydrogen acceptor which is then used in a later processing step, in forming a which acts as a solubility inhibitor with the OH groups of the pattern on, for example, a printing or electronic part Sub resin. On exposure, the hydrogen bonding between the Strate. 40 phenolic strings is severed during a reaction known as the Conventionally, laser direct imaging methods (LDI) have Wolff rearrangement, which follows photolysis of the dia been known which directly form an offset printing plate or Zoquinone moiety of the inhibitor molecule. This rearrange printed circuit board on the basis of digital data from a ment is not only very fast, but also highly exothermic. (AH computer. LDI offers the potential benefits of better line is at least -66 kcal/mol). The Sudden appearance at the quality, just-in-time processing, improved manufacturing 45 location of the solubility inhibitor of a heat pulse of that yields, elimination of film costs, and other recognized magnitude, causes a major temperature spike of not less than advantages. Examples of Such methods include: (1) an about 220°C. At the high temperature that is produced at the electrophotographic method, (2) a photopolymerization location of the solubility inhibitor, the phenolic string is method based on the combination of exposure by an Argon severed from its anchor at the DNQ and becomes inactive laser and post-heating, (3) a method in which a silver salt 50 (dispersed). This happens because it is no longer held sensitive material is deposited on a photosensitive resin, (4) together by the inductive effect of the solubility inhibitor. a method using a silver master and (5) a method in which a This model may also explains the fact that a wide range silicone rubber layer is decomposed by discharge break of heat sensitive compositions based on novolak resins, down or a laser beam. wherein different types of inhibitors are incorporated, have However, in the electro-photographic method (1), pro 55 been suggested. For example, positive-working direct laser cessing Such as charging, exposure and development are addressable printing form precursors based on phenolic complicated, and the device used for the processing is resins sensitive to UV, visible and/or infrared radiation have complex and large. In method (2), a post-heating step is been described. See, for example, U.S. Pat. No. 4,708,925, required. Further, a highly sensitive plate material is also U.S. Pat. No. 5,372,907 and U.S. Pat. No. 5,491,046. required, and handling thereof in a light room is difficult. In 60 In U.S. Pat. No. 4,708.925, the phenolic resin dissolution methods (3) and (4), silver salts are used and thus the in alkaline Solution is decreased by a radiation-sensitive processing in these methods is complicated and the cost is onium salt, Such as triphenylsulfoniumhexafluorophosphate, high. Method (5) is a relatively complete method, but there instead of DNQ, with the native solubility of the resin being remains a problem in that silicone dust remaining on the restored upon photolytic decomposition of the onium salt. surface of the offset printing plate must be removed. 65 The onium salt composition is intrinsically sensitive to UV There has been remarkable development in the area of radiation and can be additionally sensitized to infrared lasers. In particular, Solid state lasers and semiconductor radiation. US 7,279.263 B2 3 4 U.S. Pat. Nos. 5,372,907 and 5,491,046 utilize direct enesulfonic acid, dodecylbenzenesulfonic acid, phenyl positive-working systems based on a radiation-induced phosphate, diphenyl phosphate, benzoic acid, isophthalic decomposition of a latent Bronsted acid to increase the acid, adipic acid, terephthalic acid, lauric acid, and ascorbic solubility of the resin matrix on imagewise exposure. The acid or the like. described compositions can be additionally utilized as nega In U.S. Pat. No. 6.232,031 Fromson describes a positive tive-working systems with additional processing after imag working coating composition and a lithographic printing ing and predevelopment. The onium salts, quinonediaZide plate formed with a coating of that composition. The inven compounds or the like are not necessarily compatible with tion provides an infrared imageable lithographic printing the alkali aqueous solution soluble polymer compound or plate having a phenolic resin coating containing an o-diaz the material that absorbs light to generate heat. Thus, it is onaphthoguinone derivative coupled to or reacted with the difficult to prepare a uniform coating Solution and to obtain 10 resin and an infrared radiation-absorbing compound which a uniform and stable material for laser direct imaging. also couples with the resin by hydrogen bonding to insolu In U.S. Pat. Nos. 6,037,085 and 5,962,192 thermal laser bilize the resin coating. sensitive compositions are described based on azide-mate rials wherein a dye-substance is added to obtain the requisite SUMMARY OF INVENTION sensitivity. 15 A wide range of thermally-induced compositions, useful A positive radiation-sensitive composition for use with a as thermographic recording materials, are disclosed in patent radiation source comprises an acetal polymer Substance (A) GB 1.245,924, whereby the solubility of any given area of capable of being eluted in an alkali aqueous Solution, a the imageable layer in a given solvent can be increased by radiation-sensitive substance (B) and an infrared light-to heating of the layer by indirect exposure to a short duration heat converting Substance (C). The invention provides a high intensity visible light and/or infrared radiation trans positive-working photosensitive composition of good sen mitted or reflected from the background areas of a graphic sitivity for use with one or both of ultra-violet radiation and original located in contact with the recording material. an infrared laser radiation Source. Applications of the com Several systems are described which operate by many position include, but are not limited to, lithographic printing different mechanisms and use different developing materials 25 plates, such as conventional imaging systems, computer-to ranging from water to chlorinated organic solvents. Included plate systems or other direct imaging elements and applica in the range of aqueous developable compositions disclosed, tions. The composition is stable in its state before exposure are those that comprise a novolak type phenolic resin. The and has excellent handling properties. patent describes coated films of such resins that show According to a first broad aspect of the invention, there is increased solubility on heating. The compositions may con provided a radiation-sensitive composition comprising at tain heat-absorbing compounds such as carbon black or 30 least one aqueous alkali-eluable acetal polymer, a radiation Milori Blue (C.I. Pigment Blue 27); these materials addi sensitive compound and an infrared light-to-heat converting tionally color the images for their use as a recording compound. It is preferred to include a radiation-to-heat medium. converting compound in the composition to match the Other compositions that include dissolution-inhibiting sensitivity range of the composition to the wavelength of the materials are described in the patent literature. Examples 35 radiation Source. A developability enhancing Substance (D) include WO 97/39894, WO 98/42507, WO99/08879, may be added to reduce the energy required to image WO99/01795, WO99/21725, U.S. Pat. No. 6,117,623, U.S. elements prepared from the radiation-sensitive composition. Pat. No. 6,124.425, EP 940266 and WO 99/11458. However, According to a second broad aspect of the invention, there the infrared dye, or the like, functions only as a dissolution is provided a positive-working imageable element compris inhibiting agent in the non-exposed portions, and does not 40 ing, on a Substrate, a coating, the coating comprising the promote the dissolution of the binder resin in the exposed composition as aforesaid that is imageable by radiation, the portions. radiation being one of ultra-violet and infrared, and is In U.S. Pat. No. 5,840,467 Kitatani et al describe a developable using an alkaline aqueous developer solution. positive working image recording material, which comprises According to a third broad aspect of the invention, there a binder, a light-to-heat converter Substance capable of 45 is provided a radiation-sensitive printing precursor compris generating heat by the absorption of infrared rays or near ing, on a hydrophilic lithographic base with a hydrophilic infrared rays, and a heat-decomposable Substance capable of lithographic printing Surface, a coating, the coating com substantially lowering the solubility of the material when the prising the composition as aforesaid. The precursor is Substance is in the undecomposed State. Specific examples imageable by radiation, the radiation being one of ultra of the heat-decomposable Substance are diazonium salts and 50 violet and infrared, and is developable using an alkaline quinonediazide, both of which are known to practitioners in aqueous developer solution. the field to generate gas upon heating to a Suitable tempera In a further aspect of the invention, there is also provided ture. Specific examples of the binder include phenolic, a positive-working lithographic printing master comprising acrylic and polyurethane resins. Various pigments and dyes a precursor as aforesaid, imaged and developed. As further are given as potential light-to-heat converter Substances, aspects of the invention, there are provided methods for the including specifically cyanine dyes. The image recording preparation of the precursor and the master. material may be coated onto Suitable Substrates to create an imageable element. Elements so created may be imagewise DETAILED DESCRIPTION OF PREFFERED irradiated with laser light and the irradiated areas removed EMBODIMENT with an alkaline developer. Several materials capable of increasing the sensitivity of 60 The inventors have studied positive-working radiation positive-working compositions have been described. Cyclic sensitive compositions, and have found that specific com anhydrides as sensitizers are described in U.S. Pat. No. binations of an alkali aqueous solution eluable acetal poly 4,115,128; examples include phthalic anhydride, Succinic mer Substance (A), a radiation-sensitive Substance (B) and anhydride and pyromellitic anhydride. Phenols and organic an infrared light-to-heat converting Substance (C) allow the acids have also been described in JP-A Nos. 60-88942 and 65 fabrication of positive-working lithographic precursors 2-96755. Specific examples include bisphenol A, 2,3,4- using one or both of ultra-violet radiation and a infrared laser trihydroxybenzophenone, 4-hydroxybenzophenone, p-tolu radiation source. US 7,279.263 B2 5 6 According to the present invention, a positive radiation use with a radiation Source in lithographic applications. Such sensitive composition for use with a radiation source com as conventional imaging systems, computer-to-plate systems prises, as acetal polymer Substance (A), one or more alkali or other direct imaging elements and applications. It is stable aqueous Solution eluable acetal polymer compounds capable in its state before exposure and has excellent handling of being eluted in an alkali aqueous solution, a radiation properties. sensitive Substance (B) and an infrared light-to-heat con verting Substance (C). A developability enhancing Substance Polymer Substance (A) (D) may be added to reduce the energy required to image AS acetal polymer Substance (A) in the present embodi elements prepared from the radiation-sensitive composition. The acetal polymer Substance (A) has some degree of ment, there may be used any Substance having at least one eluability in alkaline aqueous solution, though preferably a 10 acetal polymer comprising at least one acetal group having low degree. In a radiation-sensitive coating formed from the a directly attached phenolic group. There may be used not compositions of the invention, the composition has low only a single polymer compound bearing Such functionality eluability due either to substance (A)'s inherently low or mixtures of Such compounds, but also mixtures contain eluability, or interactions of moieties within substance (A)'s ing resin, as a copolymerized Substance, 10 mole % or more own molecules or interaction between materials in the 15 of a phenolic resin. composition for example based on hydrogen bonding or the By way of example there may used a polymer compound like, alternatively steric effects may reduce developability. of the type described by U.S. Pat. No. 6.255,033 to Levanon The positive-working radiation-sensitive composition of et al. This patent describes an polyvinyl acetal polymer the present invention may be coated on a suitable hydro having phenolic groups, and also describes its synthesis by philic lithographic base to form a radiation-sensitive image the grafting or condensation of aldehydes onto polyvinyl able layer, thereby creating an imageable element. In a alcohol by acetalization. This polyvinyl acetal polymer can preferred embodiment of the present invention, the positive be used in the present invention, either alone, or in combi working radiation-sensitive composition is coated onto a nation with other resins, as polymer Substance (A) of the hydrophilic lithographic base and dried, thereby to form a present invention. The specification of U.S. Pat. No. 6.255. radiation-sensitive printing precursor. When the imageable 033 is hereby incorporated in full. The general structure of layer is illuminated using one or both of ultra-violet radia the acetal polymer is given by the formula:

-(CH2-CH-CH2-CH-) -(CH2-CH-CH-CH-) -(CH-CH-CH-CH-)-(CH2-CH-) (CH, -CH-) - O OH O Yi 1. O O Neil1. O O Neil1. O =o R1 k CH3 tion and an infrared laser radiation source, it becomes more in which R" is —CH2, where n=1 to 12, eluable in alkaline aqueous solution. By addition of a R’ is developability-enhancing Substance (D), the energy needed to expose the composition to obtain a desired level of 40 developability, is decreased, as compared with a coating that does not contain developability-enhancing Substance (D). R4 Areas of the coating that are not exposed to the radiation (and are therefore not heated through the absorption and conversion of the radiation to heat) do not exhibit significant 45 R5 O O-R change in the rate of elution in developer. While the addition of developability-enhancing Substance (D) may in fact to R6 some degree increase the eluability of the coated and dried composition in alkaline aqueous solution, the increase in wherein eluability of the coated and dried composition when illumi 50 R= -OH: nated is much enhanced. This provides an improved devel R= -OH or - OCH or Br or - O CH CECH opability of the image that is formed by the radiation. The and eluability in the irradiated areas does not restore to its R-Br or NO, pre-illumination value after any amount of time Subsequent to such illumination. It is this differential in eluability that and, permits developability of the image that is formed by the 55 R= -(CH), COOH, -C=CH, or radiation. To the extent that one or more of the compounds employed in the radiation-sensitive composition of the present invention may decompose during imaging, the elu ability in the irradiated areas does not restore to its original 60 value after any amount of time Subsequent to irradiation. -O- It is to be understood that an increase in the rate of eluability of the coating means, for purposes of the inven where R7-COOH, -(CH), COOH, -O-(CH), tion, an increase that is an amount useful in the image COOH, forming process. It does not include any increase that is less 65 than a useful amount in the image-forming process. The and in which t-1 to 4, and where invention provides a positive photosensitive composition for b=5 to 40 mole %, preferably 15 to 35 mole % US 7,279.263 B2 7 8 c=10 to 60 mole %, preferably 20 to 40 mole % groups, herein referred to as polymer 1, the hydroxy d=0 to 20 mole %, preferably 0 to 10 mole % Substitution being on the 3-position on the aromatic ring: e=2 to 20 mole %, preferably 1 to 10 mole % and 100 grams of AirVol 103 (trademark) a polyvinyl alcohol (a f=5 to 50 mole %, preferably 15 to 40 mole %. 98% hydrolyzed polyvinyl acetate having a number average The polyvinyl acetal polymers of U.S. Pat. No. 6,255,033 molecular weight of about 15,000, supplied by Hoechst, used in the present invention can be described as: Germany. Clariant, US), was added to a closed reaction (i) tetrafunctional polymers, in which the recurring unit vessel fitted with a water-cooled condenser, a dropping comprises a vinyl acetate moiety and a vinyl alcohol funnel and thermometer, and containing 150 grams of dem moiety and first and second cyclic acetal groups, or ineralized water and 25 grams of methanol. With continual (ii) pentafunctional polymers in which the recurring unit 10 stirring, the mixture was heated for 0.5 hour at 90° C. until it became a clear Solution. After this, the temperature was comprises a vinyl acetate moiety, a vinyl alcohol moe adjusted to 60° C. and 3 grams of concentrated sulfuric acid ity and first, second and third cyclic acetal group. All in 50 grams of methanol were added. Over a 15 minutes three of the acetal groups are six-member cyclic acetal period, a solution of 60 grams of 3-hydroxybenzaldehyde groups. One of them is Substituted with an alkyl group, and 1.4 grams of 2,6-di-t-butyl-4-methylphenol in 450 another is subsituted with an aromatic group having a 15 grams of Dowanol PMTM were added in a drop-wise manner. hydroxyl-, or a hydroxyl- and alkoxyl-, or hydroxyl-, The reaction mixture was diluted with additional 200 grams and nitro- and bromine-groups; and a third is Substi of Dowanol PMTM, and 23.2 grams of n-butyraldehyde in tuted with a carboxylic acid group, a carboxylic acid 200 grams of Dowanol PMTM were added in a dropwise Substituted alkyl group or a carboxylic acid substituted manner, upon complete addition of the aldehydes, the reac aryl group. tion was continued at 50° C. for additional 3 hours. At this Examples of Suitable aldehydes useful in preparing the stage the conversion of the butyraldhyde is completed and first cyclic acetal group of the polyvinyl acetal polymers the conversion of the 3-hydroxybenzaldehyde is close to used in this invention include: acetaldehyde, propionalde 50%. The water-Dowanol PMTM. azeotrope is distilled out hyde, n-butyraldehyde, n-valeraldehyde, n-caproaldehyde, from the reaction mixture in vacuum, Dowanol PMTM is n-heptaldehyde, isobutyraldehyde and isovaleraldehyde, 25 added to the reaction mixture during the distillation. The their mixtures and the like. distillation is complete when the water content of the Examples of Suitable aldehydes useful in preparing the reaction mixture is lower than 0.1%. The conversion of the second cyclic acetal group of the polyvinyl acetal polymers 3-hydroxybenzaldehyde is higher than 97%. The reaction used in this invention include 2-hydroxybenzaldehyde, mixture is precipitated in water. The resulting polymer is 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 2-hy filtered, washed with water and dried at 60° C. for 3 days to droxy-1-naphthaldehyde, 2,4-dihydroxybenzaldehyde, 3.5- 30 a water content of 2%. dibromo-4-hydroxybezaldehyde, 4-oxypropynyl-3-hy droxybenzaldehyde, Vanillin, isovanilin and Polymer 2 cinnamaldehyde, their mixtures, and the like. In a preferred embodiment of the present invention, the Examples of Suitable aldehydes useful in preparing the polymer employed as polymer Substance (A) is derived from third cyclic acetal group of the polyvinyl acetal polymers 35 3-hydroxybenzaldehyde, butyraldehyde and cinnamalde used in this invention include glyoxylic acid, 2-formylphe hyde by, resulting in a polyvinyl acetal resin having butyral noxyacetic acid, 3-methoxy-4-formylphenoxy acetic acid acetal groups, cinnamal acetal groups and hydroxy-Substi and propargyl aldehyde, their mixtures and the like. tuted aromatic acetal groups, herein referred to as polymer This polymer has the advantage that many different 2, the hydroxy-substitution being in the 3-position on the functional groups can be incorporated into it to tailor its 40 aromatic ring. The preparation of polymer 2 is identical to properties to the specific applications. Examples of alde that of polymer 1, except that addition of the 3-hydroxy hydes that can be used in grafting include, for example, benzaldehyde is followed by addition of 14.7 grams of acetaldehyde, n-heptaldehyde, 2,4-dihydroxybenzaldehyde, cinnamaldehyde in 150 g of Dowanol PMTM and followed 2-, 3- or 4-hydroxybenzaldehyde, Vanillin, glyoxylic acid by 16 grams of butyraldehyde in 200 g of Dowanol PMTM. and propargyl aldehyde, for example, long chain alkyl The presence of cinnamaldehyde in the composition of aldehydes to reduce the softening point (Tg) of the polymer 45 polymer 2 is thought to improve the ink-attracting ability of for ease of lamination for a dry film photoresist or aromatic the imageable areas of the plate. aldehydes, such as cinnamaldehyde to increase the oleophi Polymer 3 licity of the composition for use in a printing plate. The polymer preferably has a molecular weight range from 3,000 In a preferred embodiment of the present invention, the 50 polymer employed as polymer Substance (A) is derived from to 100,000. 2-hydroxybenzaldehyde and butyraldehyde, resulting in a Preparation of Acetal Polymers Employed in the Present polyvinyl acetal resin having butyral acetal groups and Invention. hydroxy-Substituted aromatic acetal groups, herein referred Acetalization of the polyvinyl alcohols takes place to as polymer 3, the hydroxy-Substitution being on the according to known standard methods as described, for 55 2-position of the aromatic ring. The preparation of polymer example, in U.S. Pat. No. 4,665,124; U.S. Pat. No. 4,940, 3 is identical to that of polymer 1 except that the AirVol 103 646; U.S. Pat. No. 5,169,898; U.S. Pat. No. 5,700,619; U.S. polyvinyl alcohol was replaced by Poval 103 and 2-hy Pat. No. 5,792,823; JP 09,328,519 etc. In U.S. Pat. No. droxybenzaldehyde (90 grams in 500 grams of Dowanol 6.255,033, Levanon et al. provide detailed synthesis PMTM) was used instead of the 3-hydroxybenzaldehyde examples for the acetal polymers used in the present inven 60 followed by addition of 12 grams of butyraldehyde in 200 tion. grams of Dowanol PMTM. Polymer 1 Polymer 4 In a preferred embodiment of the present invention, the In a preferred embodiment of the present invention, the polymer employed as polymer Substance (A) is derived from polymer employed as polymer Substance (A) is derived from 3-hydroxybenzaldehyde and butyraldehyde by the following 65 2-hydroxybenzaldehyde and butyraldehyde, resulting in a process, resulting in a polyvinyl acetal resin having butyral polyvinyl acetal resin having butyral acetal groups and acetal groups and hydroxy-Substituted aromatic acetal hydroxy-Substituted aromatic acetal groups, herein referred US 7,279.263 B2 9 10 to as polymer 4, the hydroxy-Substitution being on the diazidosulfonic acid O naphthoduinone-(1,2)- 2-position of the aromatic ring. The preparation of polymer diazidosulfonic acid with the acetal polymer compound (A): 4 is identical to that of polymer 3 except that the amount of the amount of Substitution on the resin by the quinonediaz 2-hydroxybenzaldehyde used was 68 grams and the amount ide is preferably between 0.1 and 25% and more preferably of the n-butyraldehyde was 23.2 grams. 5 0.3 and 20% by weight. The polymer compounds described in this specification, While not wishing to be bound to a particular theory, the preferably has a weight-average molecular weight of 2,000 inventors believe the radiation-sensitive substance (B) when to 300,000, and a dispersion degree (weight-average exposed to ultraviolet or visible radiation renders a gaseous molecular weight number-average molecular weight) of phase upon heating. The gaseous phase being produced by from 1.1 to 10. either, decomposition of the radiation-sensitive Substance A single polymer may be employed as polymer Substance 10 (B), evaporation of the radiation-sensitive substance (B) or (A) alone, or two or more types of polymers may be used in a reaction of the radiation-sensitive substance (B) with combination. The amount thereof is from 30 to 95 weight%, another moiety within the positive-working radiation-sensi preferably from 40 to 90 weight% and especially preferably tive composition. from 50 to 90 weight% of the entire content of solids in the 15 Infrared Light-to-Heat Converting Substance (C) composition. If the added amount of the polymer Substance To provide light-absorption of the laser energy in the (A) is less than 30 weight%, the durability of the imageable composition of the present invention, an infrared light-to layer deteriorates. If the added amount is more than 95% by heat converting Substance (C), capable of absorbing incident weight, the sensitivity to radiation deteriorates. radiation, preferably infrared radiation, and converting it to Radiation-Sensitive Substance (B) heat is preferably incorporated in the coating composition. The composition of the present invention comprises a The infrared radiation source for use is preferably a solid radiation-sensitive substance (B) that absorbs ultra-violet state laser or a semiconductor laser. light, decomposes and thereby causes an increase in the Preferable infrared absorbing materials for use as radia eluability of the composition. The unreacted radiation-sen tion-to-heat converting compounds are those absorbing at sitive substance (B) may also inhibit the elution of the wavelengths longer that 700 nm, such as between about 700 composition in unirradiated regions of the coated and dried 25 and 1300, with near infrared absorbing materials between composition. about 700 and 1000 nm being generally used. Preferably The radiation-sensitive substance (B) is preferably used in infrared absorbing materials are chosen to have a wave an amount of from 0.1 to 30% by weight, more preferably length of maximum absorbtion (lambda.max) within 10 nm from 0.3 to 20% by weight, based on the total solids content of the wavelength of maximum output of the radiation of the photosensitive composition. 30 SOUC. The radiation-sensitive substance (B) is a compound The radiation absorbing materials suitable for the having at least one of an onium or quinonediazide group. invented heat-sensitive compositions may be chosen from a In the present invention, the term compounds having an wide range of organic and inorganic pigments and dyes. onium group is taken to mean any compound containing an The radiation absorbing pigments that can be used may be onium group, which is intrinsically sensitive to UV radiation 35 chosen from a wide range of organic and inorganic pigments and can be additionally sensitized to infrared radiation, Such as carbon blacks, phthalocyanines or metal oxides. examples of Such onium moieties and their derivatives Green pigments: Heliogen Green D8730. D9360, and Fanal include: ammonium, iodonium, Sulphonium, bromonium, Green D 8330 produced by BASF; Predisol 64H-CAB678 chloronium, oxysulphonium, SulphoXonium, selenonium, produced by Sun Chemicals, and black pigments: Predisol telluronium, phosphonium, arsonium salts, and the organic 40 CAB2604, Predisol N1203, Predisol Black CB-C9558 pro and polymeric derivatives of Such onium moeities. Specific duced by Sun Chemicals Corp., are examples of effective examples of onium compounds are: diphenyliodonium heat absorbing pigments, and other classes of materials hexafluorophosphate, triphenylsulfonium hexafluoroanti absorbing in the near infrared region are known to those monate, phenylmethyl-Ortho-cyanobenzylsulfonium trifluo skilled in the art. romethane Sulfonate, and 2-methoxy-4-aminophenyl diazo 45 These pigments may be used with or without being nium hexafluorophosphate. subjected to surface treatment. Methods for surface treat The onium compound may incorporate any organic or ment include methods of applying a Surface coat of resin or inorganic counter ion. Examples of organic anions include wax, methods of applying Surfactant, and methods of bond carboxylate and Sulphonate anions and examples of Suitable ing a reactive material (for example, a silane coupling agent, inorganic anions include halide, Sulphate, and complex 50 an epoxy compound, polyisocyanate, or the like) to the anions containing halogen moeties Such as hexafluorophos Surface of the pigment. These methods for Surface treatment phate. are described in “Properties and Application of Metallic In the present invention, quinonediazide compounds of Soap' (published by Saiwai Shobo), “Printing Ink Technol various structures can be used. In particular o-benzoquino ogy' (CMC Publications, published in 1984) and “Latest nediazido radical or o-naphthoduinonediazide radical Pigment Applied Technology (CMC Publications, pub derived compounds, and compounds having various struc 55 lished in 1986). tures, such as those compounds as detailed in J. Kosar, the The particle size of the pigments is preferably from 0.01 “Light-Sensitive System’ (published by John Wiley & Sons, to 10 um, more preferably from 0.05 to 1 Lum and especially Inc. in 1965) pp. 339 to 353, can be used. In particular, preferably from 0.1 to 1 Lim. A particle size of the pigment Sulfonic esters or Sulfonic amides of quinonediazides pre of less than 0.01 um is not preferred from the standpoint of pared by reacting o-quinonediazide and an aromatic poly 60 the stability of the dispersed pigment in a photosensitive hydroxyl compound or an aromatic amino compound are layer coating liquid. Aparticle size of more than 10 um is not preferred. Esters between benzo-quinone-1,2-diazidosulfo preferred from the standpoint of uniformity of the formed nyl chloride or naphthoduinone-1,2-diazido-5-Sulfonyl chlo infrared sensitive layer. ride and a phenol are also preferred. These quinonediazide The method for dispersing the pigment in the composition compounds may be used either individually or in combina 65 that can be used may be any known dispersion method that tion of two or more thereof. Further examples of quinonedi is used for the production of ink or toner or the like. azide compounds include the ester of benzoquinone-(1,2)- Dispersing machines include an ultrasonic disperser, a sand US 7,279.263 B2 11 12 mill, an attritor, a pearl mill, a Super mill, a ball mill, an of material of which at least one surface is hydrophilic, impeller, a disperser, a KD mill, a colloid mill, a dynatron, thereby allowing it to hold water or aqueous media, Such as a three-roll mill and a press kneader. Details thereof are fountain solution. described in “Latest Pigment Applied Technology' (CMC Developability Enhancing Substance (D) Publications, published in 1986). The developability-enhancing compound, used as Sub For the infrared laser sensitive compositions, the dyes that stance (D), may be any one or more of the following class can be used may be any known infrared dyes, such as of compounds: commercially available dyes or dyes described in, for 1. Hydroxyl and thiol-containing compounds Such as alco example, “Dye Handbook” (edited by the Organic Synthetic 10 hols, phenols, naphthols, thiols and thiophenols. The Chemistry Association, published in 1970). Specific alcohols may have an alkyl radical of 12-60 carbon atoms examples of dyes which absorb infrared or near infrared rays or a fluoroalkyl containing 4-60 carbon atoms or a fluo are, for example, cyanine dyes disclosed in Japanese Patent roalkylaryl containing 7-60 carbon atoms. An example of Application Laid-Open (JP-A) Nos. 58-125246, 59-84356, a suitable polyol is Dimethicone copolyol SF 1488. An 59-202829, and 60-78787; methine dyes disclosed in JP-A 15 example of a monohydric phenol is nonyl phenol. Nos. 58-173696, 58-181690, and 58-194595; naphtho Examples of dihydric phenols are resorcinol and alkyl quinone dyes disclosed in JP-A Nos. 58-112793, 58-224793, resorcinols such as 4-hexylresorcinol and n-dodecylresor 59-48187, 59-73.996, 60-52940 and 60-63744; squarylium cinol. Examples of trihydric phenols are: pyrogallol, colorant disclosed in JP-A No. 58-112792; substituted aryl phloroglucinol, 1,2,4-benzenetriol and their alkyl or fluo benzo(thio)pyrylium salts described in U.S. Pat. No. 3,881, roalkyl derivatives. An example of a suitable thiol con 924; trimethinethia pyrylium salts described in JP-A No. taining compounds is 1-phenyl-1H-tetrazole-5-thiol. An 57-142645 (U.S. Pat. No. 4,327,169); pyrylium-based com example of a napthole is 1-Naphthole. pounds described in JP-A Nos. 58-181051, 58-220143, 2. An anionic lithium salt that is one of a carboxylate, 59-41363, 59-84248, 59-84249,59-146063, and 59-146061; thiocarboxylate, Sulfate, Sulfonate, phosphate, phosphite, cyanine colorant described in JP-A No. 59-216146; pentam 25 nitrate and nitrite; Examples of lithium salts of organic ethinethiopyrylium salts described in U.S. Pat. No. 4,283, acids are lithium 3-(1H, 1H,2H2H-fluoroalkyl) propi 475; and pyrylium compounds, Epolight III-178, Epolight onate and 3-(1H, 1H,2H2H-fluoroalkyl)thiopropionate, III-130 and Epolight III-125 described in Japanese Patent lithium trifluoromethane sulfonate and lithium perfluo Application Publication (JP-B) Nos. 5-13514 and 5-19702 rooctylethylsulfonate. and cyanine dyes disclosed in British Patent No. 434,875. 30 3. Esters and amides of phosphorous-containing acids, pref The pigments or dyes may be added into the radiation erably having free hydroxyl groups. Examples of phos sensitive medium for a printing plate, or to other composi phorous-containing esters are those with structures P(OH) tions, such as an etch resist in an amount of from 0.01 to 30 (OR), P(OH)(OR), P(OH)O-R-N(CH-CH weight %, preferably from 0.1 to 10 weight %, and espe OH), P(OR), O-R-NH(CH CH-OH), where cially preferably from 0.5 to 10 weight% in the case of the 35 R is an alkyl, aryl, alkylaryl, polyethylene oxide, polypro dye and from 3 to 13 weight% in the case of a pigment, with pyleneoxide or combination thereof, and where the R respect to the entire amount of solids in the material for the radical may contain fluorine atoms. Other Suitable com printing plate. If the pigment or dye content is less than 0.01 pounds are alkyl phosphonic acids, R-P(O)(OH), as weight%, sensitivity is lowered. If this content is more than well as their esters and salts, where R is as defined above. 30 weight %, uniformity of the photosensitive layer is lost 40 Examples of Suitable phosphorous-containing amides are and durability or other properties such as etch resistance of P(OH)(ONHR), P(OH)(ONHR), P(OR).O. NH the imageable layer deteriorates. (CH, CH, OH), P(OR)|O NH(CH, CH, In a further embodiment of the present invention, the OH), where R is an alkyl, aryl, polyethylene oxide, positive radiation-sensitive medium of the present invention polypropyleneoxide and combinations thereof, and where is prepared without the infrared light-too-heat converting 45 R may contain fluorine atoms. Substance (C). The radiation-sensitive medium may be 4. Polysiloxane with free hydroxyl groups. Preferably, the incorporated into a positive-working lithographic printing free hydroxyl groups are terminal ones. Examples of precursor in an imageable layer that is separate from, but suitable compounds are those with structure ROSi adjacent to, the layer comprising the converting Substance (OCH), Si(OCH)(OH), where R is an alky, aryl, (C). While it is possible to coat the layer comprising the 50 polyethyleneoxide, polypropyleneoxide group or combi converting Substance (C) on top of the imageable layer nations thereof and n is 2 to 1000. comprising the radiation-imageable medium, the preferred 5. Quaternary ammonium salts of phosphorous-containing arrangement is to have the layer comprising the converting acids, preferably having free hydroxyl groups. An substance (C) sandwiched between the imageable layer and example of a quaternary ammonium salt containing the hydrophilic lithographic base, the imageable layer being 55 hydroxyl groups is the diethanolamine Salt of perfluoro transparent to the radiation employed for imaging. When the alkyl substituted polyethyleneoxide phosphite. combined layer structure is illuminated, the layer compris 6. Compounds containing the azo functional group ing the converting Substance (C) produces heat in the N=N illuminated areas, the heat being then imagewise transferred to the adjacent imageable layer comprising the radiation 60 Examples from this class of compounds are: sensitive medium. The radiation-sensitive medium then aZonitriles such a compound is: 2-(1-cyano-1-methyl) becomes more soluble in alkaline aqueous solution in the aZo formamide, imagewise heated areas. The result is a decrease in the aZoamide compounds such as 2,2'-azobis(2-methyl-N- energy needed in exposing the composition to obtain a 1,1-bis(hydroxyethyl)-2-hydroxyethyl propiona desired level of developability, as compared with a coating 65 mide). that does not contain substance (B). The term “hydrophilic aZoamidine and cyclic azoamidine compounds such as lithographic base' is used herein to describe a plate or sheet 2,2'-aZobis(2-amidinopropane) dihydrochloride. US 7,279.263 B2 13 14 other azo compounds such as: 2,2'-azobis(2-methyl Examples of Such compounds include 2,2,4,4-tetrahy propionamide oxime). droxy-diphenyl sulphide and 2,2,4,4-tetrahydroxy 7. Linear and cyclic compounds containing the following diphenyl Sulphoxide . . . groups: 9. Substituted aromatic amides, acids and esters of them Such as 2,4-dichlorobenzamide, 3-nitrobenzamide, 2-ni —NH-NH- and trobenzoic acid, 3-nitrobenzoic acid, 2,4-dinitrobenzoic acid, 2,4-dichlorobenzoic acid, 2-hydroxy-1-naphthoic acid, 2,4-dihydroxybenzoic acid, methyl salicylate, phe nylsalicylate, methyl-4-hydroxybenzoate, butyl-4-hy -NH-NEC 10 droxybenzoate etc. 10. Sulfones such as dimethylsulfone. In general, the composition ratio of the polymer Substance (A) to the substance (D) is preferably from 99/1 to 60/40. Examples of the linear compounds are: The developability-enhancing compound D) must be present R8 NH NH R and 15 in an amount that is effective to significantly increase the sensitivity of the coating to the developer in the radiation exposed areas of the coating, that is, increased by an amount useful in the image-forming process. If the amount of substance (D) is lower than this lowest limit, the substance (D) does not significantly improve the sensitivity of the coating. If the amount of Substance (D) is more than the aforementioned upper limit, the tolerance to developer of unimaged coating is significantly reduced. Thus, both cases where are not preferred. More preferred ranges for substance (D) R'=CH, CH, SO, or CHs SO, and 25 are 1.5% to 20% and most preferred ranges are 5% to 15%, R', R= -CH where n=1 to 20 and measured by weight relative to the total Solids in the coating where R' and R are present in one of the following composition. combinations: Aqueous-Eluability Retarding Substance (E) R–H and R is one of CHs SO. , 30 The term “aqueous-ineluable' is used to mean a property CH-CH SO , of a radiation-sensitive medium coated on a Substrate, SO CH, O CH, SO. NH NH and whereby the radiation-sensitive medium is not dissolved or —SO, C.H. (CH4)-O-CH3(CH4)—SO = otherwise dispersible by an aqueous eluent. An aqueous NH-NH and eluability retarding substance (E) is a substance which 35 reduces the aqueous-eluable property. It must be remem R= CONH, and R is one of CH, SO = and bered that nearly any material may be eluted, etched or CH-CH SO = dissolved, so that this term applies only to fluids that are Examples of cyclic compound are benzotriazoles, 5-phe intended to be used in the treatment of the layer (e.g., water, nyl-1H-tetrazole and 1-phenyl-1H-tetrazole-5-thiol. low alkaline content aqueous solutions, acidic Solutions, Some of the above compounds are used as foaming 40 aqueous solutions with low amounts of organic compounds agents. Such as 10% isopropanol or methoxypropanol, and other 8. Compounds with the following structures: fountain solutions used on printing presses.) A compound that hinders the elution of the dried com position in the alkaline aqueous solution, herein referred to R15 R 14 45 as a “aqueous-eluability retarding Substance (E) may optionally be included in the coating composition. Such compounds include, but are not limited to: R 16 X-R 13 1. Nitrogen containing compounds wherein a least one nitrogen atom is either quarternised, incorporated in a 50 heterocyclic ring or quarternised and incorporated in a R17 heterocyclic ring. Examples of useful quaternised nitro gen containing compounds are quinoline and triazols, Where X is one of —S S=O, C=O, C O(NH) or imidazoline compounds, such as Monazoline C. Mona C=O(O) and where R' can be H or C to C2-alkyl, Zoline O, Monazoline CY and Monazoline Tall of which benzyl or structure E, where E is given by are manufactured by Mona Industries, quinolinium com pounds, Such as 1-ethyl-2-methyl quinolinium iodide and 1-ethyl-4-methyl quinolinium iodide, benzothiazolium compounds, such as 3-ethyl-2-methyl benzothiazolium iodide, usefully the quinolinium or benzothiazolium com 60 pounds are cationic cyanine dyes, such as, Quinoldine Blue and 3-ethyl-2-3-(3-ethyl-2 (3H)-benzothiaz olylidene)-2-methyl-1-propenylbenzothiazolium iodide, pyridinium compounds, such as cetyl pyridinium bro R21 mide, ethyl viologen dibromide and fluoropyridinium 65 tetrafluoroborate, triaryl methane dyes such as Crystal and where R', R', R', R'7, R, R', R, R can be Violet (CI basic violet 3) and Ethyl Violet and tetraalkyl one of Br, Cl, F, NO, H or OH. ammonium compounds such as Cetrimide. US 7,279.263 B2 15 16 2. Carbonyl functional group containing compounds. Sorbitan monopalmitate, Sorbitan trioleate, monoglyceride Examples of Suitable carbonyl containing compounds Stearate, polyoxyethylene-nonylphenylether, alkyldi(amino are alpha.-naphthoflavone, B-naphthoflavone, 2,3-diphenyl ethyl)glycine, alkylpolyaminoethylglycine hydrochloride, 1-indeneone, flavone, flavanone, Xanthone, benzophenone, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolium N-(4-bromobutyl)phthalimide and phenanthrenequinone. betaine, N-tetradecyl-N,N-betaine (e.g., trade name 3. A compound of general formula Amogen, manufactured by Dai-ichi Kogyo Co., Ltd.), and the like. Suitable adhesion promoters may optionally be included Where Q represents an optionally substituted phenyl or in the compositions of the invention. Suitable ones include alkyl group, in represents 0, 1 or 2, and Q represents a 10 di-acids, triazoles, thiazoles and alkyne containing materi halogen atom or an alkoxy group. Preferably Q rep als. The adhesion promoters are used in amounts between resents a C alkyl phenyl group, for example a tolyl 0.01 and 3% by weight. Other polymers may be added to reduce the cost of the formulation. Examples include ure group, or a C alkyl group. Preferably n represents 1 thane and ketone resins. The amounts of these materials can or, especially, 2. Preferably Q represents a chlorine vary between 0.5% and 25%, preferably between 2% and atom or a C alkoxy group, especially an ethoxy 15 20% by weight of solids. group. In general, the composition ratio of the polymer com 4. Ferrocenium compounds, such as ferrocenium hexafluo pound (A) to the compound (B) is preferably from 99/1 to rophosphate. 60/40. The radiation-sensitive compound (B) must be Particularly useful are dyes, such as Victoria Pure Blue present in an amount that is effective to significantly increase BO7, Crystal Violet (CI42555), Methyl Violet (CI42535), the sensitivity of the coating to the developer in the radia Ethyl Violet, Malachite Green (CI42000), Methylene Blue tion-exposed areas of the coating, that is, increased by an (CI52015), or the like. The use of such compounds is amount useful in the image-forming process. If the amount preferred where the inherent solubility of the polymer is of compound (B) is lower than this lowest limit, the com relatively high. pound (B) does not significantly improve the sensitivity of In order to achieve processing stability in a broader range 25 the coating. If the amount of compound (B) is more than the of processing conditions, a surfactant may optionally be aforementioned upper limit, the tolerance to developer of included in the compositions of the invention. Suitable unimaged coating is significantly reduced. Thus, both cases non-ionic surfactants are described in JP-A Nos. 62-251740 are not preferred. More preferred ranges for compound (B) and 3-208514 and amphoteric surfactants described in JP-A are 1.5% to 20% and most preferred ranges are 5% to 15%, Nos. 59-121044 and 4-13149. The amount of the non-ionic measured by weight relative to the total Solids in the coating or amphoteric surfactant is preferably from 0.05 to 10 30 composition. weight percent and more preferably from 0.1 to 5 by weight The radiation-sensitive printing precursor of the present % of the material for the composition. invention can be produced by dissolving the aforementioned A Surfactant for improving the applying property, for respective Substances into an appropriate solvent, filtering if example, any of the fluorine-containing Surfactants such as, necessary, and applied from a liquid in a manner known, for example, Zonyls (DuPont) or FC-430 or FC-431 (Min 35 Such as, for example, bar coater coating, spin coating, nesota Mining and Manufacturing Co.) or alternatively rotating coating, spray coating, curtain coating, dip coating, polysiloxanes such as Byk 333 (Byk Chemie), may be added air knife coating, blade coating, and roll coating, or the like, into the infrared sensitive layer. The amount of the surfactant onto a hydrophilic lithographic base. Appropriate solvents added is preferably from 0.01 to 1 weight % and more include methylenechloride, ethylenedichloride, cyclohex preferably from 0.05 to 0.5 weight % of the entire material 40 anone, methylethyl ketone, acetone, methanol, propanol, for the composition. ethyleneglycolmonomethylether, 1-methoxy-2-propanol, Image colorants may optionally be included in the com 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, positions of the invention in order to provide a visual image dimethoxyethane, methyl lactate, ethyl lactate, and toluene on the exposed plate prior to inking. As the image colorant, or the like. A single solvent may be used alone, or a dyes other than the aforementioned salt-forming organic 45 combination of two or more solvents may be used. The dyes may be used. Examples of preferred dyes, including the concentration of the aforementioned substances (all of the salt forming organic dyes, are oil-soluble dyes and basic Solid Substances including the additives) in the solvent is dyes. Specific examples are Oil-Yellow #101, Oil Yellow preferably from 1 to 50 weight %. The applied amount (of #103, Oil Pink #312, Oil Green BG, Oil Blue BOS, Oil Blue the solid) on the hydrophilic lithographic base obtained after #603, Oil Black BY, Oil Black BS, Oil Black T-505 (all of 50 application and drying differs in accordance with the use, but which are manufactured by Orient Chemical Industries Co. in general, is preferably from 0.3 to 12.0 grams per square Ltd.), provided they do not compete with the ultra-violet meter according to the application. Lesser amounts can be light absorption function of compound (B) of the composi applied to the hydrophilic lithographic base, resulting in a tion, Pure Blue BO, the tetrafluoroborate salt of Basic Blue. higher apparent sensitivity, but the film characteristics of the Specific examples include Victoria Pure Blue BO7, Crystal material are deteriorated. Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, 55 The radiation-sensitive compositions of the present inven Malachite Green (CI42000), Methylene Blue (CI52015), or tion are useful for production of printed circuit boards, for the like. The dye may be added into the material for the lithographic printing plates and other heat-sensitive ele printing plate in an amount of preferably from 0.01 to 10 ments suitable for direct imaging, including but not limited weight% and more preferably from 0.5 to 8 weight% of the to laser direct imaging (LDI). In the case of lithographic entire solid contents of the material for the composition. 60 printing, the radiation-sensitive printing precursor of the A plasticizer for providing the formed film with softness present invention employs a hydrophilic lithographic base may be added as needed in the material for the compositions which may, in a general case, comprise a separate hydro of the invention. The plasticizer may be e.g. butylphthalyl, philic layer over a substrate. Such that, when the precursor polyethyleneglycol, tributyl citrate, dibutyl phthalate, dio is developed, the hydrophilic coating layer remains, and is ctyl phthalate, tricresyl phosphate, tributyl phosphate, tet 65 employed in the printing process for retaining aqueous rahydrofurfuryl oleate, an oligomer or polymer of acrylic media Such as fountain Solution. In Such a case, there is great acid or methacrylic acid, or the like, Sorbitan tristearate, latitude in choosing a Substrate on which to coat the hydro US 7,279.263 B2 17 18 philic layer. Alternatively, the hydrophilic lithographic base known that when development is carried out by using an may be of a single material and this material, which may automatic developing machine, an aqueous solution (a typically be aluminum, may be treated to assure a hydro replenishing solution) having a higher basicity than that of philic Surface property. the developing solution is added to the developing Solution Suitable Substrates may include, for example, paper; so that many plates or pieces of can be processed without paper on which plastic Such as polyethylene, polypropylene, having to replace the developing solution in the developing polystyrene or the like is laminated; a metal plate such as an tank for a long time. In the present embodiment, such a aluminum, anodized aluminum, Zinc or copper plate; a replenishing manner is preferably used. Various Surfactants copper foil, reverse treated copper foil, drum side treated or organic solvents may be optionally added to the devel copper foil and double treated copper foil clad on a plastic oping Solution and the replenishing Solution to accelerate or laminate, a plastic film formed of, for example, cellulose 10 control developability, improve the dispersibility of devel diacetate, cellulose triacetate, cellulose propionate, cellulose opment-scum, and/or improve the affinity of image portions butyrate, cellulose acetate butyrate, cellulose nitrate, poly on the printing plate with ink. Other agents commonly used ethylene terephthalate, polyethylene, polystyrene, polypro in positive plate developers may also be included in the pylene, polycarbonate, or polyvinyl acetal; a paper or a developer solution. plastic film on which the aforementioned metal is vapor 15 The composition is usually post-processed with water; deposited or laminated; glass or glass in which a metal or optionally containing, for example, a surfactant. In the case metal oxide is vapor deposited or the like. of printing plates a desensitizing solution containing gum As the Substrate in the present embodiment for a printing arabic or a starch derivative is used. Various combinations of plate, a polyester film, or an aluminum plate is preferred, and these treatments can be used as the post-processing carried an aluminum plate is especially preferred because of its out when the imageable medium of the present embodiment stable dimensions and relatively low cost. A plastic film on is used in its different applications. which aluminum is laminated or vapor-deposited may be used. The composition of the aluminum plate applied to the EXAMPLES present invention is not specified, and the aluminum plate may be prepared according to any of the known methods, for 25 The invention is exemplified as follows: example of roughening, anodizing and post anodizing treat ments. The thickness of the aluminum plate used in the present embodiment is from about 0.1 to 0.6 mm, preferably Substances (Weight, %) from 0.15 to 0.5 mm. Substance (A), Polymer 3 or 4 55 The radiation-sensitive printing precursor produced as 30 Substance (B), O-naphthaquinonediaZide 2 described above is usually subjected to image-exposure and Substance (C), ADS 830A (trademark) 2 developing processes. In a preferred embodiment, radiation Substance (D), 4-hexylresorcinol 2O sensitive compositions as described above are applied as a Resole resin LB 9900 2O coating on a hydrophilic lithographic base (for example an N,N-Diethylaniline 1 aluminum plate) to form a lithographic printing precursor. The precursor can be imaged (for example by imagewise 35 The substances of the composition are dissolved in MEK: exposure to one or both of ultra-violet and infrared radia Dowanol PMTM mixture, filtered and coated on the surface tion), and the imaged precursor developed to form a posi of anodized aluminum. After drying the resulting precursor tive-working lithographic printing plate, using a conven has a dry coating weight of ~1.0-2.0 grams/m. The precur tional alkaline aqueous developer solution. When the Sor may be imaged in a Creo Lotem 400 Quantum imaging precursor has a separate imageable layer and layer compris 40 device or a THEIMER MONTAKOP 135 print down frame. ing the converter Substance, the development process The exposed precursor is developed in ~5-10 wgt % potas removes both layers, to reveal the underlying hydrophilic sium metasilicate solution in water for ~20-60 seconds, Surface. rinsed off with water and dried to produce the printing In a preferred embodiment of the invention, the light master. source for an active light beam which is used in the 45 Substance (B), substance (D) and N,N-Diethylaniline are image-exposure, is preferably a light source emitting light available from: having a luminous wavelength within the ranges 320 nm to Sigma-Aldrich Canada Ltd. 450 nm for the ultra-violet function, and from 700 nm to 2149 Winston Park Dr, 1300 nm in the infrared and is especially preferably a solid Oakville, state laser or a semiconductor laser. Preferably, the radia 50 Ontario, tion-sensitive printing precursor based on the radiation L6H 68 sensitive medium of the present invention is sensitive to ADS 830A (trademark) is available from: radiation of wavelength between 320 nm to 450 nm for the American Dye Source, ultra-violet function, and 700 nm and 1300 nm, and more preferably between 700 nm and 1000 nm for the infrared Montreal, function. 55 QC, The developing solution and replenishing solution for the Canada radiation-sensitive printing precursor of the present inven Resole resin LB 9900 is available from: tion may be a conventionally known alkali aqueous Solution Bakelite Aktiengesellschaft Such as, for example, Sodium metasilicate, potassium ter Iserlohn-Letmathe tiary phosphate, ammonium secondary phosphate, sodium 60 Gennaer Str. 2-4 carbonate, potassium borate, Sodium hydroxide, ammonium D-58642 Iserlohn hydroxide, potassium hydroxide, tetraalkylammonium There have thus been outlined the important features of hydroxides; and organic alkali agents such as, alkyl amines, the invention in order that it may be better understood, and alkyl ethanolamines or diamines. The alkali agent may be in order that the present contribution to the art may be better used alone, or a combination of two or more may be used. 65 appreciated. Those skilled in the art will appreciate that the Among these, especially preferred developing solutions conception on which this disclosure is based may readily be are aqueous solutions of silicates and hydroxides. It is utilized as a basis for the design of other methods and US 7,279.263 B2 19 20 apparatus for carrying out the several purposes of the and in which t-1 to 4, and where invention. It is most important, therefore, that this disclosure b=5 to 40 mole %, preferably 15 to 35 mole % be regarded as including Such equivalent methods and c=10 to 60 mole %, preferably 20 to 40 mole % apparatus as do not depart from the spirit and scope of the d=0 to 20 mole %, preferably 0 to 10 mole % invention. e=2 to 20 mole %, preferably 1 to 10 mole % What is claimed is: and f=5 to 50 mole %, preferably 15 to 40 mole %. 1. A radiation-sensitive composition comprising: 5. The radiation-sensitive composition of claim 1, a. at least one polyvinyl acetal comprising at least one wherein the radiation-sensitive Substance is capable of ren acetal group, with at least one acetal group having a dering a gaseous phase upon heating. directly attached phenolic group and 10 6. The radiation-sensitive composition of claim 5, b. a radiation-sensitive Substance that comprises at least wherein the gaseous phase is produced by at least one of: one of: a. the decomposition of the radiation-sensitive Substance; i. a quinonediazide group and b. the evaporation of the radiation-sensitive Substance and ii. an onium salt, c. a reaction of the radiation-sensitive substance with the composition further comnrising an infrared light 15 another moiety within the positive-working radiation to-heat converting Substance. sensitive composition. 2. A radiation-sensitive composition comprising: 7. An imageable element comprising, a. at least one polyvinyl acetal comprising at least one ... a Substrate and acetal group, with at least one acetal group having a ... a coated and dried layer of the composition of claim 1 directly attached phenolic group and on a surface of the substrate. b. a radiation-sensitive Substance that comprises at least 8. An imageable element comprising, one of: a Substrate and i. a quinonediazide group and s ... a coated and dried layer of the composition of claim 2 ii. an onium salt, on a surface of the substrate. said composition further comprising a developability 25 9. An imageable element comprising, enhancing Substance. a. a Substrate and 3. The radiation-sensitive composition of claim 2, further b. a coated and dried layer of the composition of claim 3 comprising an aqueous-eluability retarding Substance, or on a surface of the substrate. said at least one polyvinyl acetal is aqueous alkali-eluable 10. An imageable element comprising, and is present in an amount of from 40 to 95 weight %. 30 a. a Substrate and 4. The composition of claim 1, wherein the polyvinyl b. a coated and dried layer of the composition of claim 4 acetal has the structure on a surface of the substrate.

-(CH-CH-CH-CH-) -(CH-CH-CH2-CH-) -(CH-CH-CH-CH-)-(CH2-CH-) (CH, -CH-) - O OH O O "N,-O "S.- Nc1 = O RI R2 CH3

in which R" is —CH2, where n=1 to 12, and 11. An imageable element comprising, R’ is a. a Substrate and 45 b. a coated and dried layer of the composition of claim 5 on a surface of the substrate. 12. An imageable element comprising, a. a Substrate and b. a coated and dried layer of the composition of claim 6 on a surface of the substrate. 50 13. A radiation-sensitive printing precursor comprising: a. a base, and wherein b. a radiation-sensitive composition on a surface of the R= -OH: base, the composition comprising: R= -OH or - OCH or Br or - O CH CECH 55 iii. an acetal polymer Substance comprising at least an and acetal group with a directly attached phenolic group and B-Br or NO, iv. a radiation-sensitive Substance that comprises at R= -(CH), COOH, -C=CH, or least one of: 60 (1) a quinonediazide group and (2) an onium salt, the radiation-sensitive printing precursor further compris ing an infrared light-to-heat converting Substance. -O- 14. The radiation-sensitive composition of claim 13, 65 further comprising a developability-enhancing Substance, or where R7-COOH, (CH), COOH, - O (CH), said at least one polyvinyl acetal is aqueous alkali-eluable COOH and is present in an amount of from 40 to 95 weight %. US 7,279.263 B2 21 22 15. The radiation-sensitive composition of claim 14, b. produced by the evaporation of the radiation-sensitive further comprising an aqueous-eluability retarding Sub Substance and Stance. c. produced by a reaction of the radiation-sensitive Sub 16. The radiation-sensitive printing precursor of claim 13, stance and another moiety within the positive-working wherein the acetal polymer has the structure radiation-sensitive composition.

-(CH-CH-CH-CH-) -(CH-CH-CH2-CH-) -(CH2-CH-CH2-CH-)-(CH2-CH-) (CH, -CH-) - O OH O O "N,10 "S.19 Nc1 = O RI R2 CH

in which R" is —CH2, where n=1 to 12, and 19. A method for making a radiation-sensitive precursor, R is the method comprising the steps of coating on a surface of a base a layer of a radiation-sensitive composition and 2O drying the layer, wherein the composition comprises: R4 a. a polyvinyl acetal derived from polyvinyl alcohol by condensation with aldehydes and comprising at least an R5 O O-r acetal group with a directly attached phenolic group 25 and R6 b. a radiation-sensitive substance that comprises at least one of: wherein V. a quinonediazide group and R= -OH: vi. an onium salt, R= -OH or OCH or Br or O CH, C=CH wherein the radiation-sensitive composition further and comprises an infrared light-to-heat converting Sub B-Br or NO, stance with a W within 10 nm of the wavelength of R= -(CH), COOH, -C=CH, or maximum output of the radiation source. 35 20. The radiation-sensitive composition of claim 19, further comprising a developability-enhancing Substance. 21. The radiation-sensitive composition of claim 20, further comprising an aqueous-eluability retarding Sub 40 Stance. where R'=COOH, -(CH), COOH, -O-(CH), 22. The method of claim 19, for making a radiation COOH sensitive precursor wherein the acetal polymer has the and in which t-1 to 4, and where Structure

-(CH2-CH-CH2-CH-) -(CH2-CH-CH-CH-) -(CH-CH-CH-CH-)-(CH2-CH-) (CH, -CH-) - O OH "N,-O O N1 O R1 R2

b=5 to 40 mole %, preferably 15 to 35 mole % 55 in which R' is —CH2, where n=1 to 12, and c=10 to 60 mole %, preferably 20 to 40 mole % R’ is d=0 to 20 mole %, preferably 0 to 10 mole % e=2 to 20 mole %, preferably 1 to 10 mole R4 and f=5 to 50 mole %, preferably 15 to 40 mole %. 17. The radiation-sensitive printing precursor of claim 13 60 R5 O O-R wherein the radiation-sensitive substance (B) is capable of rendering a gaseous phase upon heating. R6 18. The radiation-sensitive printing precursor of claim 17, wherein wherein the gaseous phase is at least one of: 65 R= -OH: a. produced by the decomposition of the radiation-sensi R= -OH or - OCH or Br or - O CH CECH tive Substance; and US 7,279.263 B2 23 24 B-Br or NO, stance with a W within 10 nm of the wavelength of R= -(CH), COOH, -C=CH, or maximum output of the radiation source. 26. The method of claim 25, wherein the composition further comprises a developability-enhancing Substance. 27. The method of claim 26, wherein the composition further comprising an aqueous-eluability retarding Sub -O- Stance. 28. The method of claim 25, wherein the polyvinyl acetal has the structure

-(CH2-CH-CH-CH-) -(CH2-CH-CH-CH-) -(CH-CH-CH2-CH-)-(CH2-CH-) (CH, -CH-) - O OH O 1. O O O O O R1 k R3 CH

where R'=COOH, -(CH), COOH, -O-(CH), in which R" is —CH2 where n=1 to 12, and COOH R’ is and in which t-1 to 4, and where b=5 to 40 mole %, preferably 15 to 35 mole % 25 R4 c=10 to 60 mole %, preferably 20 to 40 mole % d=0 to 20 mole %, preferably 0 to 10 mole % R5 O O-R e=2 to 20 mole %, preferably 1 to 10 mole % R6 and f=5 to 50 mole %, preferably 15 to 40 mole %. 30 23. The method of claim 19, wherein the radiation wherein sensitive Substance is capable of rendering a gaseous phase R= -OH: upon heating. R= -OH or - OCH or Br or - O CH CECH 24. The method of claim 23, wherein the gaseous phase is 35 and at least one of: B-Br or NO, a. produced by the decomposition of the radiation-sensi R= -(CH)2 COOH, -C=CH, or tive Substance;

b. produced by the evaporation of the radiation-sensitive 40 Substance and c. produced by a reaction of the radiation-sensitive Sub -O- stance and another moiety within the positive-working radiation-sensitive composition. where R7=COOH, (CH), COOH, -O-(CH), 25. A method for making a lithographic master, the 45 COOH method comprising the steps of and in which t-1 to 4, and where a. providing a radiation-sensitive precursor, the precursor b=5 to 40 mole %, preferably 15 to 35 mole % comprising c=10 to 60 mole %, preferably 20 to 40 mole % vii. a lithographic base and 50 d=0 to 20 mole %, preferably 0 to 10 mole % viii. a coated and dried layer of a radiation-sensitive e=2 to 20 mole %, preferably 1 to 10 mole % composition, the composition comprising and f=5 to 50 mole %, preferably 15 to 40 mole %. 29. The method of claim 25, wherein the radiation (1) a polyvinyl acetal derived from polyvinyl alcohol sensitive Substance is capable of rendering a gaseous phase by condensation with aldehydes and comprising at 55 upon heating. least an acetal group with a directly attached 30. The method of claim 29, wherein the gaseous phase is phenolic group and at least one of: (2) a radiation-sensitive Substance that comprises at a. produced by the decomposition of the radiation-sensi least one of a quinonediazide group and an onium tive Substance; salt, 60 b. produced by the evaporation of the radiation-sensitive b. imagewise irradiating areas of the layer with imaging Substance and radiation to render the layer more eluable in an aqueous c. produced by a reaction of the radiation-sensitive Sub alkaline Solution in the areas irradiated and stance and another moiety within the positive-working c. treating the resulting imaged precursor with alkaline radiation-sensitive composition. aqueous solution to remove eluable parts of the radia 65 31. The method of claim 25 for making a lithographic tion-sensitive coating, wherein the composition further master, the method comprising imagewise irradiating areas comprises an infrared light-to-heat converting Sub of the radiation-sensitive layer with ultraviolet imaging US 7,279.263 B2 25 26 radiation to render the layer more eluable in an aqueous b. infrared imaging radiation to render the layer more alkaline solution in the areas irradiated. eluable in an aqueous alkaline Solution in the irradiated 32. The method of claim 25, wherein the imagewise areas and irradiation is performed using at least one of c., a combination of ultraviolet and infrared imaging a.. ultraviolet imaging radiation to render the layer more radiation to render the layer more eluable in an aqueous eluable in an aqueous alkaline solution in the areas alkaline Solution in the irradiated areas. irradiated, k . . . .

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION

PATENT NO. : 7,279.263 B2 Page 1 of 1 APPLICATIONNO. : 1 1/157204 DATED : October 9, 2007 INVENTOR(S) : Jonathan W. Goodin

It is certified that error appears in the above-identified patent and that said Letters Patent is hereby corrected as shown below:

Col. 19, claim 1, line 15 In Claim 1, delete “comnrising and insert -- comprising --, therefor. Col. 19, claim 2, line 26 In Claim 2, after "enhancing insert -- substance and an infrared light-to-heat converting --. Col. 20, claim 13, line 55 In Claim 13, before “acetal delete “an and insert -- a polyvinyl --, therefor. Col. 20, claim 13, line 55 In Claim 13, after “polymer delete “substance. Col. 21, claim 16, line 5 In Claim 16, before “acetal insert -- polyvinyl --. Col. 21, claim 16, line 5 In Claim 16, after “acetal delete “polymer. Col. 21, claim 16, line 58 In Claim 16, after “mole insert -- % --. Col. 22, claim 22, line 42 In Claim 22, before “acetal insert -- polyvinyl --. Col. 22, claim 22, line 42 In Claim 22, after “acetal delete “polymer. Col. 25, claim 32, line 3 In Claim 32, delete “claim 25, and insert -- claim 25 --, therefor. . 26, claim 32, line 4 In Claim 32, delete “c, and insert -- c. --, therefor.

Signed and Sealed this Twenty Second Day of April, 2008 WDJ

JON. W. DUDAS Director of the United States Patent and Trademark Office