Developer agent for positive type photosensitive compound

1. Field of the Invention

This invention relates to a developer agent for a positive type photosensitive compound having a near-infrared wavelength region laser sensitive characteristic in which a photosensitive portion of the compound exposed and reacted with a laser of the near-infrared wavelength region is enabled to be solubilized in the developer liquid.

2. Description of the Related Art

As the prior art positive type photosensitive compound having a near infrared wave length region laser sensitive characteristic in which a photosensitive portion of the compound exposed and reacted with a laser of the near infrared wavelength region is enabled to be dissolved in the developer liquid, it is possible to refer to the following technical documents.

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10(1998)-26826 [Patent Document 2] Japanese Patent Laid-Open No. Hei 10(1998)-90881 [Patent Document 3] Japanese Patent Laid-Open No. Hei 10(1998)-161304 [Patent Document 4] Japanese Patent Laid-Open No. Hei 11(1999)-231515 [Patent Document 5] Japanese Patent Laid-Open No. Sho 61(1986)-167948

Using of the developer agent commercially available at the market in the practical gravure printing showed that developing of one roll caused the developer agent to deteriorate in quality at once and developing of the second roll and its subsequent rolls could not be performed at all.

In order to apply the developer agent practically to the gravure printing operation, it is desired to have a capability of developing at least about 100 rolls. In addition, it is also desired to have no probability that the developing capability diminishes and the developing operation cannot be carried out due to quite low aging deterioration in the processing capability when a developing operation is carried out after elapsing by 2 to 3 days through one week, and cleaning or washing is carried out again after discharging out all the developing liquid in the developing tank.

The present invention has been invented in view of the aforesaid circumstances and it is an object of the present invention to provide a developer agent for positive type photosensitive compound having no probability that the developing capability diminishes and the developing operation cannot be carried out when the developing operation is performed after elapsing by 2 to 3 days through one week, and all the developer liquid in a developing tank is discharged and replaced with new liquid because it has a capability of sufficiently developing 100 or more rolls, preferably about 300 to 400 rolls enabled to be practically applied for a process roll for a gravure printing and an aging deterioration in the processing capability is quite low.

The invention described in claim 1 of the present invention provides a developer agent for positive type photosensitive compound having a near-infrared wavelength region laser sensitive characteristic in which a photosensitive portion of the compound exposed and reacted with a laser of the near-infrared wavelength region is enabled to be solubilized in developer liquid, wherein the same is comprised of:

a) water; b) either one of or two kinds or more of tetramethyl ammonium hydroxide, benzyl triethyl ammonium hydroxide, benzyl trimethyl ammonium hydroxide, tetrabutyl ammonium hydroxide, tetrapropyl ammonium hydroxide, ortho silicate soda, potassium hydroxide, sodium hydroxide, sal soda applied as either organic or non-organic alkali capable of becoming a major material; and c) either one of or two kinds or more of potassium pyrophosphate, tripolyphosphate soda, hexametaphosphoric soda, triphosphate soda and monophosphate soda applied as liquid agent having dampening action for preventing a reduction in pH value.

In accordance with the developer agent for positive type photosensitive compound of the present invention, original liquid and water are mixed to each other to clean or wash, positive type photosensitive compound is applied to coat on the roll for a gravure printing and to form a coated photosensitive film, near-infrared wavelength region laser is illuminated and radiated, the film is exposed to the laser to draw a positive type latent image, then developing operation is carried out, resulting in that even if 300 or more rolls are processed, it keeps a pH value of 13.0 or more in a stable manner, a clear pattern can be attained in a short period of time, a superior developing state can be realized. Additionally, an aging deterioration in the processing capability is quite low, so that even if the developing operation is carried out after elapsing by 2 to 3 days through one week, there is no probability that the developing capability diminishes, the developing operation cannot be performed and all the developer liquid in the developing tank are discharged out of the tank and replaced with new developer liquid. 500 rolls could be developed and processed after supplementing new rolls corresponding to the number of processed rolls every time the roll was developed with developer liquid of 50 litters because the aging deterioration in the processing capability was quite low.

The present invention provides a developer agent for positive type photosensitive compound having a near infrared wavelength region laser sensitive characteristic in which a photosensitive portion of the compound exposed and reacted with a laser of near infrared wavelength region is enabled to be dissolved in developer liquid.

As the positive type photosensitive compound, it is possible to apply compound including alkaline soluble organic high molecular substances having at least one kind of phenolic hydroxyl group such as novolac resin, resol resin, polyphenol resin and copolymer of acrylic acid derivative having phenolic hydroxyl group; and photo-thermal conversion pigment such as organic or non-organic pigment or dye, organic pigment, metal, metal oxide, metal carbide and metal boride and the like having an absorbing band at a part of or all of the near infrared region with a wavelength region of 650 to 1300 nm so as to absorb near infrared rays and converting it into heat. It is preferable that this positive type photosensitive compound contains closeness improving agent.

It is preferable that an inclusion rate of the alkaline soluble organic high-molecular substance in the positive type photosensitive compound is 2 to 98 wt % and it is further preferable that it is 30 to 90 wt %. It is preferable that an inclusion rate of the photo-thermal conversion pigment in the positive type photosensitive compound is 2 to 60 wt % and it is further preferable that it is 3 to 50 wt %.

This positive type photosensitive compound is normally processed to become a positive type photosensitive film having the photosensitive compound layer formed on the surface of the supporting member in such a way that this compound is coated on either a copper plated surface or a copper sulphate plated surface of the process roll for gravure printing of the surface of the supporting member as solution having each of the aforesaid compositions dissolved in solvents such as Cellosolve type solvent, propylene glycol type solvent and the like, thereafter this is heated and dried with a heater or is not heated and not dried with a heater. A rate of application of the solvent in respect to a total amount of photosensitive compound is normally in a range of about 1 to 20 times by a weight ratio.

As the coating method, it is possible to apply a kiss-coating, a dip-coating, a rotary coating, a roll-coatings a wire bar coating, an air knife coating, a blade coating and a curtain coating and the like. A coating amount is preferably in a range of about 3 to 6 μm.

Alkaline soluble organic high molecular substance having phenolic hydroxyl group is a major composition to form a resist, and this is a binder resin having a low adherence to either a copper plating surface or a copper sulphate plating surface, wherein a major chain portion or side chain portion of the molecules is cut by heat, it becomes a low molecule where the alkaline soluble characteristic is further improved and a part of it is makes abilation.

As alkaline soluble organic high molecular substance having a phenolic hydroxyl group, alkaline soluble high molecular substance having a phenolic hydroxyl group described in Japanese Patent Laid-Open No. Hei 11 (1999)-231515 such as novolac resin, resol resin, polyvinylphenol resin and copolymer of acrylic acid derivative having phenolic hydroxyl group and the like can be applied as they are and in particular, novolac resin or polyvinylphenol resin is preferable.

Novolac resin is resin in which at least one kind of phenols is copolymerized with at least one kind of aldehydes or ketons under a presence of acid catalyst. In particular, mixed phenols including m-cresol, p-cresol, 2,5-Xylenol, 3,5-Xylenol and resolcinol; or polycondensation material of mixed phenols including phenol, m-cresol and p-cresol, and formaldehyde, where a weight-average molecular weight (MW) in conversion of polystylene through a gel permeation chromatography measurement is preferably 1,500 to 10,000.

Resol resin is resin similarly polycondensated except the fact that alkaline catalyst is used in place of acid catalyst in polycondensation of novolac resin.

Polyvinyl phenol resin is resin in which either one kind of or two kinds or more of hydroxystylene, for example, are polymerized under a presence of radical polymerization initiator or cation polymerization initiator. It is preferable to apply either a polymerization substance of hydroxystylene having alkyl group with carbon numbers 1 to 4 in a benzene ring as substituent or polymerization substance of hydroxystylene of benzene ring with no substituent.

Photothermal conversion pigment has an absorbing region at a part of or an entire near-infrared wavelength region of 650 to 1300 nm, a characteristic for absorbing a laser beam in the near-infrared wavelength region and providing a thermal decomposition and contributes to a low molecular formation of alkaline solubilization and ablasion caused by thermal cutting of molecules in alkaline soluble organic high-molecular substance having the aforesaid phenolic hydroxyl group.

As photothermal conversion pigment, the photothermal conversion pigment described in Japanese Patent Laid-Open No. Hei 11 (1999)-231515 such as organic or non-organic pigment or dyestuff, organic pigment, metal, metal oxide, metal carbide, metal boride and the like having an absorbing region at either a part of or an entire near-infrared region of 650 to 1300 nm can be applied fully as they are, and so-called cyanine type pigment in a broad sense or the like can be applied as a representative one in which complex rings including nitrogen atom, oxygen atom or sulfur atom and the like are coupled with polymethine (—CH═) n , and more practically, quinoline type (so-called cyanine type), indole type (so-called indocyanine type), benzothiazole type (so-called thiocyanine type), iminocyclohexadiene type (so-called polymethine type), pyrylium type, thiapyrylium type, squarylium type, chroconium type, and azulenium type can be applied and in particular, it is preferable to apply quinoline type, indole type, benzothiazole type, iminocyclohexadiene type, pyrylium type, thiapyrylium type.

The developer agent of the present invention includes a) water; b) either one of or two kinds or more of tetramethyl ammonium hydroxide, benzyl triethyl ammonium hydroxide, benzyl trimethyl ammonium hydroxide, tetrabutyl ammonium hydroxide, tetrapropyl ammonium hydroxide, ortho silicate soda, potassium hydroxide sodium hydroxide, sal soda applied as either organic or non-organic alkali capable of becoming a major material; and c) either one of or two kinds or more of potassium pyrophosphate, tripolyphosphate soda, hexametaphosphoric soda, triphosphate soda and monophosphate soda applied as liquid agent having dampening action for preventing a reduction in pH value.

Surface active agent and developing promoter agent can be added in their appropriate rate.

As this water, either distilled water or tap water can be used.

Preferred embodiments in Tables 1 to 15 and the comparative example in Table 16 were carried out such that a process roll was fixed to a photosensitive film coating device (manufactured by Think Laboratory Co., Ltd.) installed in a coating chamber kept at a humidity of 40%, a positive type photosensitive compound (manufactured by Mitsubishi Chemical Co., Ltd.) was coated on the roll, then it was dried up to 130° C., a positive type photosensitive film was formed in such a way that its residual solvent might become 2% or less and its film thickness might become about 2 to 3 μm, a laser with a wavelength of 830 nm was illuminated, radiated to cause the film to be exposed, a positive type latent image was drawn on it and the tested roll was made and a development was carried out.

Original liquid of developer agent for positive type photosensitive compound with a rate of composition indicated in each of the preferred embodiments in the tables was made, water and the original liquid was applied to clean the tank with a rate of 3:1 so as to cause the tank in the developing device to become full (50 litters), a developing was carried out at 25° C., and a presence or non-presence of the residual substance, aging capability and developing processing capabilities were checked. The developing processing capability was calculated through a conversion of area after performing an entire developing operation for a non-exposed roll.