Abstract: A developer composition for resists which has a high dissolution rate (high developing sensitivity). The developer composition for resists comprises an organic quaternary ammonium base as a main component and a surfactant containing an anionic surfactant represented by formula (I).

Abstract: A method of treating a laser exposed lithographic printing plate with a deactivating solution followed by overall irradiation is described. The plate comprises on a substrate a photosensitive layer capable of photo hardening. The deactivating solution is capable of deactivating the photo hardening capability of the photosensitive layer in the non-hardened areas so that the overall irradiation does not cause hardening of the photosensitive layer in the non-hardened areas. The deactivation and overall irradiation cause one or more chemical or physical changes to the photosensitive layer, such as further hardening of the imaged areas, improved contrast, improved developability, or improved substrate hydrophilicity. The overall irradiated plate is further developed on press with ink and/or fountain solution or off press with a developer. For off-press development, the developer may be used as the deactivating solution.

Abstract: Process for the posttreatment of an imaged lithographic printing plate comprising (a) providing a lithographic printing plate comprising image areas and non-image areas on a lithographic substrate; (b) bringing the lithographic printing plate of step (a) into contact with a solution comprising a hydrophilic polymer comprising structural units derived from the following compounds: (i) a compound comprising both polyalkylene oxide chains and at least one structural unit which is free-radical polymerizable, and (ii) a monomer capable of copolymerizing with the free-radical polymerizable structural unit of (i) and furthermore comprising at least one acidic functional group with pKs<5, wherein the acidic functional group can be present as a free acid group or in the form of a salt; (c) drying.

Abstract: The present invention provides a method for producing a regenerated porous sheet including a step of bringing a porous sheet which has adsorbed an uncured part of a photosensitive resin, into contact with a solvent to separate the uncured part from the porous sheet, the porous sheet that has adsorbed the uncured part being produced by curing a specific area of a printing surface of a printing original plate in which the printing surface is formed from a photosensitive resin, and then absorbing the uncured part of the printing surface into a porous sheet, so as to conduct a development.

Abstract: A method of deactivating and on-press developing an exposed lithographic printing plate is disclosed. The plate comprises on a substrate a photosensitive layer developable with ink and/or fountain solution and capable of hardening upon exposure to a radiation. The plate is exposed with the radiation, deactivated, and then on-press developed with ink and/or fountain solution. The deactivation of the exposed plate allows the handling of the plate under regular office light or any other light without causing the hardening of the non-exposed areas of the photosensitive layer.

Abstract: The present invention provides a light sensitive planographic printing plate material which excels in printing durability and tone reproduction property in high resolution printing as in FM screening, and an image formation method employing the light sensitive planographic printing plate material.

Abstract: This invention relates to a photosensitive element for use as a flexographic printing plate and a process for preparing the plate from the element. The photosensitive element has at least one photopolymerizable elastomeric layer that comprises a binder, a monomer, a photoinitiator, an onium salt, and a leuco dye. Upon exposure to actinic radiation, the onium salt and leuco dye react resulting in a change of color in polymerized portions of the photopolymerizable layer. The color change provides enhanced image color contrast in the photosensitive element.

Abstract: A process for producing a laser engravable printing substrate, comprising the step of forming a layer of photosensitive resin composition on a cylindrical support or sheeted support and the step of irradiating the formed layer of photosensitive resin composition with light to thereby provide a layer of cured photosensitive resin of 50 ?m to 50 mm thickness, wherein the light for irradiation of the photosensitive resin composition layer contains a ray of 200 to 450 nm wavelength and wherein the light illuminance on the surface of the photosensitive resin composition layer is in the range of 20 mW/cm2 to 2 W/cm2 when measured with the use of UV meter (trade name “UV-M02” manufactured by Ohku Seisakusho) and filter (trade name “UV-35-APR Filter” manufactured by Ohku Seisakusho) and in the range of 3 mW/cm2 to 2 W/cm2 when measured with the use of the above UV meter and filter (trade name “UV-25 Filter” manufactured by Ohku Seisakusho).

Abstract: A method of on-press developing a thermosensitive lithographic printing plate with ink and/or fountain solution is described. The lithographic plate comprises on a substrate a thermosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to an infrared radiation. The printing plate can be a pre-coated plate in the form of sheet or web, or can be prepared on press by coating a thermosensitive layer onto a substrate that is a sheet material or a seamless sleeve mounted on a plate cylinder or is the surface of a plate cylinder of the lithographic press.

Abstract: The invention provides a method for making a printing form having a relief surface on a floor from a photosensitive element. The method involves generating a polymerization rate curve for the photosensitive element from a step exposure test by measuring a cure response, such as floor thickness or one or more relief image characteristic/s, of the element relative to an energy density of a source of actinic radiation. The method exposes a photosensitive element to the source of actinic radiation based on energy density that accounts for changes in intensity of lamps used for the source of actinic radiation.

Abstract: A laser sensitive lithographic printing plate comprises an electrochemically grained, anodized, hydrophilically treated aluminum substrate with a reflection optical density of 0.30 or higher; a free radical polymerizable photosensitive layer; and a water soluble or dispersible overcoat. The photosensitive layer comprises a polymeric binder, a free radical polymerizable monomer, a free radical initiator, and a sensitizing dye. Such dark aluminum substrate in combination with the hydrophilic treatment allows both clean background and good printing durability. Such plate can be exposed with a suitable laser at lower dosage to cause hardening in the exposed areas. The exposed plate can be developed with a regular liquid developer or with ink and/or fountain solution.

Abstract: Systems and methods are described for improved yield and line width performance for liquid polymers and other materials. A method for minimizing precipitation of developing reactant by lowering a sudden change in pH includes: developing at least a portion of a polymer layer on a substrate with an initial charge of a developer fluid; then rinsing the polymer with an additional charge of the developer fluid so as to controllably minimize a subsequent sudden change in pH; and then rinsing the polymer with a charge of another fluid. An apparatus for minimizing fluid impingement force on a polymer layer to be developed on a substrate includes: a nozzle including: a developer manifold adapted to supply a developer fluid; a plurality of developer fluid conduits coupled to the developer manifold; a rinse manifold adapted to supply a rinse fluid; and a plurality of rinse fluid conduits coupled to the developer manifold.

Abstract: An image-recording materials containing (A) a compound having a specific partial structure and at least one group selected from an acid group having a pKa of 11 or less, the derivative of the acid group and a group capable of generating the acid group, a lithographic printing plate precursor having an image-recording layer containing the compound (A), and a lithographic printing method using the lithographic printing plate precursor, are provided.

Abstract: This invention relates to a method and apparatus for thermally developing a photosensitive element. The thermal development method includes heating the photosensitive element to a temperature sufficient to cause a portion of a composition layer in the element to liquefy, soften, or melt, contacting the heated photosensitive element with a development medium to absorb the liquefied portion at a contact location, and removing the development medium from the photosensitive element with a remover at a location away from the contact location.

Abstract: The electric conductivity of the developer is measured every constant period, a development replenisher is replenished every constant time as a time lapse replenisher in an amount based on a set value of a time lapse replenishment rate, a development replenisher is replenished every processing of a constant area of a photosensitive lithographic printing plate precursor(s) as a processing replenisher in an amount based on a set value of a processing replenishment rate, a calculated value of electric conductivity is calculated from the amounts of the time lapse replenisher and the processing replenisher, the set values of the time lapse replenishment rate and the processing replenishment rate are increased or decreased according to the result of the comparison of the calculated value with the measured value, and the value of the difference between the calculated value and the measured value is displayed as a degree of a developer activity.

Abstract: A method of making a lithographic printing plate includes the steps of: providing a lithographic printing plate precursor including (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer and (ii) a coating provided thereon which includes hydrophobic thermoplastic polymer particles; exposing the coating to heat, thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; and developing the precursor by applying a gum solution to the coating, thereby removing non-exposed areas of the coating from the support. According to the above method, the plate precursor can be developed and gummed in a single step.

Abstract: An exposure system includes an exposure section provided within a chamber for irradiating a resist film formed on a wafer with exposing light through a mask with an immersion liquid provided on the resist film. It further includes a drying section for drying the surface of the resist film after the irradiation.

Abstract: A method of making a lithographic printing plate includes the steps of: a) providing a lithographic printing plate precursor including (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer, (ii) a coating on the support including a photopolymerizable layer, and, optionally, an intermediate layer between the photopolymerizable layer and the support, wherein the photopolymerizable layer includes a polymerizable compound and a polymerization initiator, b) image-wise exposing the coating in a plate setter, c) optionally, heating the precursor in a pre-heating unit, d) developing the precursor off-press in a gumming unit by treating the coating of the precursor with a gum solution, thereby removing the non-exposed areas of the photopolymerizable layer from the support, wherein the photopolymerizable layer further includes a polymer containing an acid group and a basic nitrogen-containing compound capable of neutralizing the acid group, or wherein the photopolymerizable layer furt

Abstract: A presensitized lithographic plate comprises a support and a hydrophilic image-recording layer. The hydrophilic image-recording layer contains a hydrophilic polymer and an agent capable of converting hydrophilic to hydrophobic when the agent is heated. The hydrophilic polymer comprises a main chain and branched chains. Each of the branched chain comprises a hydrophilic chain having a molecular weight in the range of 200 to 1,000,000. A hydrophilic substrate and a lithographic printing process are also disclosed.

Abstract: A photosensitive planographic printing plate comprising a substrate and a photosensitive layer including a photopolymerizable compound, wherein the photosensitive layer and the substrate are provided between them with an undercoat layer including a (co)polymer having structural units having ethylenically unsaturated groups bonded with silicon atoms and phosphonic acid groups.

Abstract: The present invention provides a planographic printing plate precursor having a support, a photosensitive layer and a protective layer. The photosensitive layer contains at least an infrared absorbing agent, a polymerization initiating agent, a polymerizable compound and a binder polymer having repeating units represented by the following Formula (i). Further, the protective layer contains at least an inorganic lamellar compound. In Formula (i), R1 represents a hydrogen atom or a methyl group; R2 represents a connecting group having two or more types of atom selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom and having 2 to 82 atoms in total; A represents an oxygen atom or —NR3—, and R3 represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; and n is an integer of 1 to 5.

Abstract: A printing method comprising: imagewise exposing a lithographic printing plate precursor comprising a support and an image recording layer being removable with a fountain solution or a combination of a printing ink and a fountain solution and loading the exposed lithographic printing plate precursor on a plate cylinder of a printing press, or loading the lithographic printing plate precursor on a plate cylinder of a printing press and imagewise exposing the loaded lithographic printing plate precursor, supplying at least a fountain solution comprising a compound represented by the formula (I) defined herein to the exposed lithographic printing plate precursor so as to remove an unexposed area of the image recording layer; and performing printing.

Abstract: A method of on-press developing a laser sensitive lithographic printing plate with ink and/or fountain solution is described. The printing member comprises on a substrate a photosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser. The plate is exposed with a laser and on-press developed with ink and/or fountain solution. The exposure and development are performed with the plate under lightings that contain no or substantially no radiation below a wavelength selected from 400 to 650 nm, or in the dark or substantially dark.

Abstract: A method for making a lithographic printing plate is disclosed which comprises the steps of: (i) providing a negative-working, heat-sensitive lithographic printing plate precursor comprising a support having a hydrophilic surface or which is provided with a hydrophilic layer and a coating provided thereon, the coating comprising an image-recording layer which comprises hydrophobic thermoplastic polymer particles and a hydrophilic binder, wherein the hydrophobic thermoplastic polymer particles have an average particle size in the range from 45 nm to 63 nm, and wherein the amount of the hydrophobic thermoplastic polymer particles in the image-recording layer is at least 70% by weight relative to the image-recording layer; (ii) exposing the coating to heat or infrared light, thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; (iii) developing the precursor by applying an aqueous alkaline solution, thereby removing non-exposed areas of the coating from the su

Abstract: A relief printing original plate including a substrate, a photosensitive resin layer thereon that is photosensitive to ultraviolet radiations, and a mask layer thereon having both ultraviolet and non-ultraviolet absorbability, the ultraviolet absorbability being deactivatable in response to receiving non-ultraviolet radiation. A method for producing a relief printing plate by using the original plate is also provided.

Abstract: Disclosed is a processing method of a light sensitive planographic printing plate material comprising an aluminum support and provided thereon, a light sensitive layer and an oxygen shielding layer in that order, employing an automatic developing machine comprising a pre-washing section with a pre-washing water, a development section and a post-washing section with a post-washing water, the processing method comprising the steps of imagewise exposing the light sensitive planographic printing plate material, pre-washing the exposed material with the pre-washing water to remove the oxygen shielding layer, developing the pre-washed material with a developer with a pH of from 10 to 12 containing no silicate, and post-washing the developed material with a post-washing water, wherein pre-washing water used for pre-washing is introduced into post-washing water and reused.

Abstract: An objective is to provide a positive-working planographic printing plate material exhibiting scratch resistance useful for high productivity in large size printing, and excellent sensitivity and development latitude against a developer having a low pH or a worn-out inactive developer, as well as a method of preparing a planographic printing plate employing the planographic printing plate material. Also disclosed is a positive-working planographic printing plate material possessing a support and provided thereon, a light-sensitive layer, wherein the light-sensitive layer possesses a compound containing a residue of a cyclic ureide compound having a cyclic structure having at least two amide bonds (—NHCO—) in a cycle.

Abstract: Disclosed are a developer for an imagewise exposed light sensitive planographic printing plate material and a process of manufacturing a planographic printing plate employing the developer, wherein the developer is an aqueous solution with a pH at 25° C. of from 3.0 to 9.

Abstract: This invention describes an exposure apparatus comprising a light measuring device and a light transmitting clamp designed to compress a photocurable (photopolymer) package for use in manufacture of a hand stamp plate, the package typically consisting of a sachet containing a liquid photopolymer. The liquid photopolymer is specifically engineered to cure under ambient lighting conditions eliminating the requirement for fluorescent tubes to create the UV light to cure the photopolymer. The light measuring device is designed to inform the user of the required exposure time for the printing plate.

Abstract: A flexographic printing plate is prepared from a photosensitive element having a photopolymerizable elastomeric layer with specific rheological properties. The element is imagewise exposed and thermally treated to form a relief structure suitable for flexographic printing.

Abstract: High speed violet or ultraviolet laser sensitive lithographic printing plate comprising on a hydrophilic substrate a specific photosensitive composition is described. The photosensitive layer comprises a polymeric binder, a multifunctional (meth)acrylate monomer, a free-radical initiator, and a sensitizing dye, with specific weight ratio of the monomer to the polymer. Combination of multifunctional urethane (meth)acrylate monomer and multifunctional non-urethane (meth)acrylate monomer can be advantageously used. The plate is imagewise exposed with a violet or ultraviolet laser at a dosage of less than 300 ?J/cm2, and then developed with an aqueous developer or with ink and/or fountain solution.

Abstract: To provide a developer composition for resists, capable of improving dimensional controllability of a resist pattern. The developer composition for resists comprises an organic quaternary ammonium base as a main component, said developer composition further comprising an anionic surfactant represented by the following general formula (I), and SO42?, the content of S42? being from 0.01 to 1% by mass. In the formula, at least one of R1 and R2 represents an alkyl or alkoxy group having 5 to 18 carbon atoms and the other one represents a hydrogen atom, or an alkyl or alkoxy group having 5 to 18 carbon atoms, and at least one of R3, R4 and R5 represents an ammonium sulfonate group or a sulfonic acid-substituted ammonium group and the others represent a hydrogen atom, an ammonium sulfonate group or a sulfonic acid-substituted ammonium group.

Abstract: The present invention relates to an improved compressible flexographic printing plate that uses a compressible layer comprising a polyurethane (meth)acrylate resin and microspheres. The process of the invention produces a chemically fused printing plate that eliminates the need for an adhesive to secure the compressible layer to the back of the printing plate.

Abstract: A method of making a lithographic printing plate is disclosed which comprises the steps of providing a lithographic printing plate precursor comprising (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer and (ii) a coating provided thereon which comprises hydrophobic thermoplastic polymer particles; exposing the coating to heat, thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; developing the precursor by applying a gum solution to the coating, thereby removing non-exposed areas of the coating from the support. According to the above method, the plate precursor can be developed and gummed in a single step.

Abstract: A development replenisher replenishment method in an automatic developing machine for a photosensitive lithographic printing plate precursor, the method comprising: developing a plurality of sheets of exposed photosensitive lithographic printing plate precursors with a developer containing an electrolyte while replenishing a development replenisher to keep a developer activity constant, wherein an electric conductivity of the developer is measured every constant period; a development replenisher is replenished every constant time as a time lapse replenisher in an amount based on a set value of a time lapse replenishment rate; a development replenisher is replenished every processing of a constant area of a photosensitive lithographic printing plate precursor(s) as a processing replenisher in an amount based on a set value of a processing replenishment rate; a calculated value of an electric conductivity is calculated from an amount of the time lapse replenisher and an amount of the processing replenisher; and

Abstract: A planographic printing method including: providing a planographic printing plate precursor including a substrate and an image recording layer which is disposed on the substrate and contains (A) an infrared absorber, (B) a polymerization initiator and (C) a polymerizable compound; imagewise exposing the planographic printing plate precursor with an infrared laser; and supplying oil-based ink and an aqueous component to the exposed planographic printing plate precursor without any development treatment, so as to print an image. A region of the planographic printing plate precursor that has not been exposed with an infrared laser is removed during the printing. The polymerizable compound of (C) is represented by the following formula (1): wherein Ar1, R1, Z and n are as defined in the claims and the specification.

Abstract: Positive-working imageable elements comprise a radiation absorbing compound and inner and outer layers on a substrate having a hydrophilic surface. The inner layer comprises a combination of two different polymeric binders one of which has an acid number of at least 30, which combination of polymers provides improved post-development bakeability (more quickly baked or cured at lower temperatures) and desired digital speed with no loss in chemical resistance.

Abstract: A lithographic printing plate precursor capable of forming an image without alkali development, comprising a hydrophilic support and a laser-sensitive photopolymerizable layer, wherein the photopolymerizable layer or other layer included in the lithographic printing plate precursor contains a copolymer containing at least a repeating unit having at least one ethylenically unsaturated bond and a repeating unit having at least two functional groups capable of interacting with a surface of the support or a copolymer containing at least a repeating unit having at least two ethylenically unsaturated bonds and a repeating unit having at least one functional group capable of interacting with a surface of the support.

Abstract: Disclosed is a method of processing a light sensitive planographic printing plate material comprising an aluminum support, and provided thereon, a photopolymerizable light sensitive layer containing a polymerizable ethylenically unsaturated compound, a photopolymerization initiator, and a polymer binder, the method comprising the steps of imagewise exposing the light sensitive planographic printing plate material, developing the exposed light sensitive planographic printing plate material with a developer to obtain a planographic printing plate, the developer containing no silicate or containing a silicate in amount of not more than 0.1% by weight in terms of SiO2, and plate processing the resulting planographic printing plate with a plate protecting solution containing a phosphonic acid compound at a temperature of from 40 to 90° C.

Abstract: A method of making a lithographic printing plate is disclosed which comprises the steps of (1) providing a lithographic printing plate precursor comprising (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer and (ii) a coating provided thereon which comprises hydrophobic thermoplastic polymer particles; (2) exposing the precursor to IR-light or heat, thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; (3) applying a hydrophilic protective layer on the coating; and then, (4) while the precursor is mounted on a print cylinder of a printing press, developing the precursor by supplying an aqueous dampening liquid and/or ink to said precursor while rotating said print cylinder whereby the coating and the hydrophilic protective layer are removed from the support on the non-exposed areas.

Abstract: A heat sensitive lithographic printing plate precursor is disclosed comprising on a support having a hydrophilic surface or which is provided with a hydrophilic layer, a coating comprising an infrared light absorbing agent and a copolymer which comprises a plurality of recurring units X having a hydrophilic polymeric pendant group and a plurality of recurring units Y having a hydrophobic polymeric pendant group. Said coating is capable of switching from a hydrophilic state into a hydrophobic state after exposure to heat and/or infrared light.

Abstract: A lithographic printing process which comprises the steps of: imagewise exposing to infrared light a presensitized lithographic plate which comprises a hydrophilic support and a removable image-forming layer containing an infrared absorbing agent having the absorption maximum within an infrared region and a dye precursor having substantially no absorption within a visible region to change the dye precursor to a visible dye having an absorption within a visible region within the exposed area, and to make the image-forming layer irremovable within the exposed area; removing the image-forming layer within the unexposed area of the lithographic plate mounted on a cylinder of a printing press; and then printing an image with the lithographic plate mounted on the cylinder of the printing press. The other processes are also disclosed.

Abstract: Disclosed are a process of correcting a planographic printing plate with an image, and a correction solution for correcting the planographic printing plate; the process comprising the steps of scraping stains at the non-image portions or undesired images at the image portions in the planographic printing plate off, and then covering the scraped portions with hydrophilic film.

Abstract: Radiation-sensitive element comprising (a) a substrate with at least one hydrophilic surface and (b) a radiation-sensitive coating on at least one hydrophilic surface of the substrate, wherein the coating comprises: (i) at least one free-radical polymerizable monomer and/or oligomer and/or polymer with at least one ethylenically unsaturated group each, (ii) at least one absorber selected from photoinitiators and sensitizers, which is capable of absorbing radiation of a wavelength in the range of 250 to 1,200 nm and (iii) at least one stabilizer comprising in its molecule at least one group capable of inhibiting free-radical polymerization, and at least one other group capable of sorption at the hydrophilic surface of the substrate.

Abstract: A method for eliminating unwanted ink-receptive sections in positive working printing plates resulting from shading of the surface layer during exposure by the clamps holding the plate on the exposure apparatus following development of an imagewise exposed precursor. Accordingly the areas that are shaded are identified prior to development and the surface layer is scored in those areas to a depth and density sufficient to result in the scored layer being removed during development but not deep enough to damage the underlying hydrophilic layer.

Abstract: Disclosed are a planographic printing plate material and a planographic printing plate preparing process, the planographic printing plate material comprising a support and provided thereon, an image formation layer containing a colorant (a) having an absorption band in a wavelength region of from 700 to 1200 nm, a polymerization initiator (b) and a polymerizable ethylenically unsaturated compound (c), wherein the polymerization initiator (b) is a compound represented by the formula R1—CX2—(C?O)—R2.

Abstract: A planographic printing plate precursor includes a substrate and an image recording layer provided thereon, the image recording layer being capable of recording through exposure to an infrared ray and containing at least (A) an infrared absorbing agent, (B) a polymerization initiator comprising an onium salt formed by an onium cation and a carboxylic acid anion, where the carboxylic acid anion has an acid group, a hetero atom and an aromatic group, (C) a polymerizable compound and (D) a binder polymer. The planographic printing plate precursor is exposed imagewise with an infrared laser. Then, printing is carried out using the exposed planographic printing plate precursor, which is set in a printer without being subjected to any developing process, by feeding an oil based ink and an aqueous component onto the planographic printing plate precursor. Unexposed areas of the planographic printing plate precursor are removed during the printing process.

Abstract: A positive-working lithographic printing starting plate for an infrared laser is provided that includes a support having a hydrophilic surface and a heat-sensitive layer provided above the support. The heat-sensitive layer includes a water-insoluble and alkali-soluble resin, an infrared-absorbing dye, and a sulfonium salt represented by Formula below. The heat-sensitive layer increases its solubility in aqueous alkaline solution upon exposure to an infrared laser.

Abstract: This invention pertains to a system for thermally treating a photosensitive element to form a relief structure suitable for flexographic printing. The system of the invention comprises a plurality of consecutively arranged blotting stations for removing uncured photopolymer from the imaged surface of the photosensitive printing element. The flexographic plates produced in the apparatus of the invention are especially suited for use in printing newspapers and other publications.

Abstract: This invention provides an undercoating layer material and a filler material containing a resin component having at least a substituent group which is capable of releasing a terminal group to form a sulfonic acid residue upon application of predetermined energy, and a solvent. The resin component has at least a repeating unit represented by formula (1): wherein n is an integer of 1 or more, X represents a C1 to C10 linear or branched alkyl chain, an aromatic or alicyclic alkyl chain or an alkyl ester chain, and Y is a substituent group forming a sulfonic acid residue upon application of predetermined energy.