JPH07117748B2 - Photosensitive composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel photosensitive composition for a lithographic printing plate.
More specifically, the present invention is an improvement of the invention described in JP-A-59-78340, which has high sensitivity and excellent storage stability,
Moreover, the present invention relates to a photosensitive composition having good production suitability.

[Prior art]

As a photosensitive composition used for a photosensitive lithographic printing plate, a composition containing a photosensitive diazo resin and a polymer compound has hitherto been widely known (for example, JP-B Nos. 41-6813 and 47-1167).
No. JP-A-48-9804, 47-24404, 47-38302,
50-30604, 50-118802, 54-98613, 54-98
No. 614).

The photosensitive diazo resin used in these photosensitive compositions is mainly a coupling product of paradiazodiphenylamines and an aldehyde.

Recently, as the demand for higher sensitivity of printing plates has increased, a photosensitive composition containing a high-sensitivity diazo resin in which the condensation product has a high molecular weight by devising a synthetic method has been proposed (for example, JP Sho 55-25,093, 59-78,340, 61
-91,654, British patent 1,600,350).

The sensitivity of these photosensitive compositions is practically sufficient, and the storage stability is also good. However, the solubility tends to decrease as the diazo resin has a higher molecular weight, insoluble matter is deposited during the production of the photosensitive solution, it takes a long time to dissolve, and a highly toxic solvent such as dimethylformamide, There was a problem such as being forced to use ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, dichloromethane and the like.

[Object of the Invention]

Therefore, an object of the present invention is to provide a photosensitive composition having high sensitivity, good storage stability, and excellent production suitability.

[Structure of Invention]

The present invention relates to a photosensitive composition, which is a photosensitive high molecular weight diazo compound represented by the following general formula [I], wherein the compound contains 20 mol% or more of a compound in which n in the general formula is 6 or more. It is characterized by containing a photosensitive high molecular weight diazo compound.

(However, R ₁ ; methyl, methoxy, ethoxy or hydrogen atom, R ₂ ; methyl, methoxy, ethoxy or hydrogen atom, R ₃ ; lower alkyl (1 to 5 carbon atoms), lower alkoxy (1 to 4 carbon atoms) or Hydrogen atom, R; hydrogen atom, methyl or phenyl X; alkyl (carbon atom 6 to 18) benzenesulfonate anion n; 1 to 200) The present inventors are keen to improve JP-A-59-78340. As a result of repeated research, as the photosensitive diazo resin, the specific high molecular weight diazo resin derived by the present invention has high sensitivity and good storage stability, and also has excellent organic solvent solubility, which is extremely advantageous in terms of production. The inventors have found out that, and have reached the present invention.

Hereinafter, the present invention will be specifically described.

The photosensitive high molecular weight diazo resin used in the present invention is obtained by polycondensing a diazonium salt and an aldehyde such as formaldehyde, paraformaldehyde, acetaldehyde or benzaldehyde in sulfuric acid, hydrochloric acid, phosphoric acid or methanesulfonic acid. At that time, the diazonium salt and the aldehyde were each mixed at a molar ratio of 1:
The predetermined condensation product described in the present specification by charging at 0.0 to 1: 1.1, preferably 1: 1 and by reacting at a high temperature and / or for a long time as long as the reaction temperature does not decompose the diazonium salt. Can be manufactured.

The counter anion X of this diazo resin has 6 to 6 carbon atoms.
The benzene sulfonate anion substituted with 18 alkyl groups is used for stable salt formation and endowment of particularly high organic solvent solubility. If the number of carbon atoms in the alkyl group is 5 or less, the solubility in organic solvents is not sufficient, and if the number of carbon atoms is 19 or more, the crystallinity of the diazo resin becomes extremely low, and when diazo resin is synthesized, it becomes a candy and is difficult to handle. Becomes

The photosensitive high molecular weight diazo compound of the present invention has the general formula [I]
It is necessary to contain 20 mol% or more of those in which n is 6 or more. This is because if it is less than 20 mol%, the sensitivity is low and the storage stability becomes poor.

Although the diazo resin of the present invention can be used alone,
It is also possible to use it by mixing it with another organic solvent-soluble diazo compound. Among the other diazo resins that can be mixed, particularly preferable for maintaining the high sensitivity which is the object of the present invention, as the diazo resin of the general formula [I], the anion X is benzene sulfonate, toluene sulfonate, alkylnaphthalene sulfonate, Examples thereof include diazo resins such as 2-hydroxy-4-methoxybenzophenone-5-sulfonate and hexafluorophosphate. When the diazo resins are mixed and used, the proportion of the diazo resin of the present invention is preferably 50% by weight or more, and particularly preferably 70% by weight or more based on the total diazo resins. If it is less than 50% of the total diazo resin, other mixed diazo resins are likely to deposit insoluble matters during the production of the photosensitive solution.

When the diazo resin of the present invention is used in a photosensitive composition for a printing plate, it is generally blended with a lipophilic organic polymer compound in order to obtain high printing durability. As the lipophilic organic polymer compound that can be used for this purpose, polyamide, polyether, polyester, polycarbonate,
Examples thereof include polystyrene, polyurethane, polyvinyl chloride and copolymers thereof, polyvinyl butyral resin, polyvinyl formal resin, shellac, epoxy resin, phenol resin and acrylic resin.

As a particularly suitable organic polymer compound, a copolymer containing acrylic acid, methacrylic acid, crotonic acid or maleic acid as an essential component, for example, 2-hydroxyethyl acrylate as described in JP-A-50-118802. Or a multi-component copolymer of 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, acrylic acid or methacrylic acid, and optionally other copolymerizable monomer, described in JP-A-53-120903. Such as acrylic or methacrylic acid, acrylic acid, or methacrylic acid esterified with a group containing a dicarboxylic acid ester residue and having a hydroxy group at the terminal, and optionally other copolymerizable monomer A multi-component copolymer, a monomer having an aromatic hydroxyl group as described in JP-A-54-98614. Copolymer (for example, N- (4-hydroxyphenyl) methacrylamide), acrylic acid or methacrylic acid and optionally other copolymerizable monomer, JP-A-56-4144. Mention may be made of multicomponent copolymers of alkyl acrylates, acrylonitrile or methacrylonitrile and unsaturated carboxylic acids as described. In addition to these, acidic polyvinyl alcohol derivatives and acidic cellulose derivatives are also useful. In addition, Japanese Patent Publication No. 54-19773, Japanese Patent Publication No. 57-94747, No. 60-182437, Japanese Patent Application No. 60-198742, in which polyvinyl acetal or polyurethane is alkali-solubilized,
The polymer compounds described in Japanese Patent Application No. 60-263233 are also useful.

The content of the diazo resin and the polymer compound in the photosensitive composition is preferably 3 to 30% by weight of the diazo resin and 97 to 70% by weight of the polymer compound based on the total amount of both of them. . The smaller the content of the diazo resin is, the higher the sensitivity is. However, when the content is lower than 3% by weight, it is insufficient for photo-curing the polymer compound, and the photo-cured film is swollen by the developing solution during development and the film becomes weak. On the other hand, if the content of the diazo resin is more than 30% by weight, the sensitivity becomes low and practical problems arise. Therefore, a more preferable range is 5 to 20 diazo resins.
The polymer compound is 95 to 80% by weight in weight%.

Various additives may be further added to the photosensitive composition used in the present invention. For example, alkyl ethers (for example, ethyl cellulose, methyl cellulose) for improving coating properties, fluorine-based surfactants or silicone-based surfactants, plasticizers for imparting flexibility and abrasion resistance to the coating film (for example, triplet). Dil phosphate, dihexyl phthalate, dioctyl phthalate, trioctyl phosphate, tributyl phosphate, tributyl citrate, polyethylene glycol, polypropylene glycol), acridine dye, cyanine dye, styryl dye as a coloring substance for visualizing the image area after development , Pigments such as triarylmethane dyes and phthalocyanines, general stabilizers for diazo resins (phosphoric acid, phosphorous acid, pyrophosphoric acid, oxalic acid, tartaric acid, malic acid, pyridinedicarboxylic acid, boric acid, benzenesulfonic acid , To Ensulfonic acid, naphthalenesulfonic acid, alkylnaphthalenesulfonic acid, polyacrylic acid and its copolymer, polyvinylphosphonic acid and its copolymer, polyvinylsulfonic acid and its copolymer, 5-nitronaphthalene-1-phosphonic acid, 4-chlorophenoxymethylphosphonic acid, sodium phenyl-methyl-pyrazolone sulfonate, 2-phosphonobutanetricarboxylic acid-1,2,4,1-phosphonoethanetricarboxylic acid-1,2,2,1-hydroxyethane-
1,1-disulfonic acid) can be added. The amount of these additives added varies depending on the intended purpose, but generally 0.5 to 30 relative to the total solid content of the photosensitive composition.
% By weight.

The photosensitive composition of the present invention is dissolved in a suitable organic solvent and coated on a support having a hydrophilic surface so that the dry coating weight is 0.5 to 5 g / m ² to obtain a photosensitive lithographic printing plate. You can The concentration of the photosensitive composition at the time of coating is preferably in the range of 1 to 50% by weight, and the coating solvent used is methanol, ethanol, butanol, ethylene chloride, chlorobenzene, tetrahydrofuran, acetone,
Methyl ethyl ketone, cyclohexanone, ethyl acetate,
Butyl acetate, methyl lactate, ethyl lactate, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, 1
-Methoxy-2-propanol, dimethylformamide, dimethylsulfoxide, γ-butyrolactone, diacetone alcohol, do not dissolve diazo resin or polymer compound such as a small amount of water or toluene in these mixed solvents or these solvents or mixed solvents A mixed solvent containing a solvent is also suitable.

A suitable support for applying the photosensitive composition of the present invention is a dimensionally stable plate. Such dimensionally stable plates include those conventionally used as a support for printing plates, which can be preferably used in the present invention. Examples of such a support include paper and plastics (for example, polyethylene, polypropylene, polystyrene, etc.)
Laminated paper, metal plates such as aluminum (including aluminum alloys), zinc, copper, etc., celluloses diacetate, celluloses triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate , Films of plastics such as polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc., papers or plastic films laminated or vapor-deposited with the above metals, and the like. Among these supports, the aluminum plate is particularly preferable because it is dimensionally remarkably stable and inexpensive.

Among the aluminum plates, roughened aluminum is more preferable, and it can be manufactured by various methods. For example, wire brush graining, brush graining in which a slurry of abrasive particles is poured and roughening with a nylon brush, ball graining, chemical graining, electrolytic graining, and complex graining combining these graining methods. Grain the surface. Next, if necessary, anodization may be performed with a direct current or an alternating current power source in sulfuric acid, phosphoric acid, oxalic acid, boric acid, chromic acid, sulfamic acid or a mixed acid thereof to form a strong passivation film on the aluminum surface. preferable. The aluminum surface is hydrophilized by such a passivation film itself, but if necessary, it is further described in US Pat. No. 2,714,066 and US Pat.
Silicate treatment (sodium silicate, potassium silicate) described in 1,461, potassium fluorozirconate treatment described in US Pat. No. 2,946,638, described in US Pat. No. 3,201,247 Phosphomolybdate treatment, which is described in German Patent 1,091,433, polyacrylic acid treatment, German Patent 1,13
4,093 specification and British Patent 1,230,447 polyvinyl phosphonic acid treatment described in the specification, phosphonic acid treatment described in JP-B-44-6409, U.S. Pat.
Phytic acid treatment described in Japanese Patent No. 951
Hydrophilic by composite treatment consisting of a hydrophilic organic polymer compound and a divalent metal described in JP-A No. 8-16893 and JP-A No. 58-18291 and undercoating of other water-soluble polymer having a sulfonic acid group. Those subjected to a chemical treatment are particularly preferable. Other hydrophilic treatment methods include silicate electrodeposition described in US Pat. No. 3,658,662.

In the present invention, the coating amount of the photosensitive composition coated on the roughened aluminum plate is 0.3 to 5 g / solid content.
m ² is preferable, and more preferably 0.5 to 3.5 g / m ² . The solid content concentration of the photosensitive composition giving such a coating amount is 1
-50% by weight is suitable, preferably 2-20% by weight. As a method for coating the photosensitive composition solution on the aluminum plate, a conventionally known method such as roll coating, bar coating, spray coating, curtain coating, and spin coating can be used. The applied photosensitive composition solution is preferably dried at 50 to 120 ° C. As for the drying method, the temperature may be lowered at the beginning and pre-dried and then dried at a high temperature, or may be directly dried at a high temperature.

A lithographic printing plate having a photosensitive composition layer which is applied on a roughened aluminum plate and dried is subjected to imagewise exposure and then developed with an aqueous solution to develop a negative relief image with respect to the original image. Suitable light sources for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, and ultraviolet laser beams.

The aqueous solution used for the photosensitive lithographic printing plate refers to one having a pH of 6 to 13 and water of 75% by weight or more,
If necessary, use a small amount of organic solvent, surfactant, alkaline agent,
Antifouling agents, water softeners, etc. can be added. For example, JP-A-51-77401, JP-A-51-80228, and JP-A-53-442
No. 02, JP-A-55-52054 and JP-A-57-136647, which are organic solvents having a solubility in water of 10% by weight or less at room temperature (benzyl alcohol). , Ethylene glycol monophenyl ether), alkaline agents (triethanolamine, diethanolamine,
Monoethanolamine, sodium phosphate, sodium carbonate, anionic surfactant (aromatic sulfonate, dialkylsulfosuccinate, alkylnaphthalenesulfonate, fatty acid salt, alkyl sulfate ester salt), nonionic surfactant (polyoxyethylene Alkyl ethers, polyoxyethyl alkylaryl ethers, polyoxyethylene polyoxypropylene block polymers), and if necessary stain inhibitors (sodium sulfite, sodium salt of sulfopyrazolone) and water softeners (ethylenediaminetetraacetic acid tetrasodium salt, nitrilo-3). (Trisodium acetate salt) combined and dissolved.

〔The invention's effect〕

According to the present invention, it is possible to provide a photosensitive composition having high sensitivity, good storage stability, and excellent production suitability.

Next, the present invention will be described with reference to synthesis examples and examples.

[Synthesis example]

Synthesis Example 1 4-diazodiphenylamine sulfate (purity 99.5%) 29.4
g was slowly added to 70 ml of 96% sulfuric acid at 25 ° C. and stirred for 20 minutes. Paraformaldehyde (purity 92%) 3.26g
Is slowly added over about 10 minutes, and the mixture is added to the mixture at 30 ° C. for 4 hours.
The mixture was stirred for a time to allow the condensation reaction to proceed. The mixing molar ratio of the diazo compound and formaldehyde is 1: 1. The reaction product was poured into 2 l of ice water with stirring and treated with a cold concentrated aqueous solution in which 130 g of zinc chloride was dissolved. The precipitate was collected by suction filtration and 1 part of the partially dried solid was collected.
Was dissolved in water, filtered, cooled with ice, and treated with an aqueous solution containing 44 g of sodium n-dodecylbenzenesulfonate. The precipitate was collected by filtration and air dried to obtain 44.5 g of high molecular weight diazo compound (1).

The obtained diazo compound (1) was added to 1 in methyl cellosolve.
Coupling with -phenyl-3-methyl-5-pyrazolone gave the dye.

When the molecular weight distribution of this dye was measured by gel permeation chromatography (GPC), it contained about 30 mol% of a 10-mer or more.

Synthesis Example 2 33.3 g of 4-diazo-4′-methoxydiphenylamine phosphate (purity 97.0%) was gradually added to 70 ml of 96% sulfuric acid at 10 ° C. and stirred for 20 minutes. 3.26 g of paraformaldehyde (92% purity) was added slowly over about 30 minutes and the mixture was stirred at 10 ° C for 10 hours. The reaction product was poured into 2 l of ice water with stirring and treated with a cold concentrated aqueous solution in which 130 g of zinc chloride was dissolved. The precipitate is collected by suction filtration,
The partially dried circuitous body was dissolved in 1 of water, filtered, cooled with ice and treated with an aqueous solution of 30 g of sodium n-hexylbenzenesulfonate. The precipitate was collected by filtration and dried in air to obtain a high molecular weight diazo compound (2) 2
7.6g was obtained.

After treating the obtained diazo compound (2) as described in Synthesis Example 1, GPC measurement showed that the 10-mer or more was about 35 mol%.
Was included.

Synthetic Example 3 32.5 g of 4-diazo-3-methoxydiphenylamine sulfate (purity 99.8%) was gradually added to 70 ml of 85% phosphoric acid at 20 ° C. and stirred for 20 minutes. 3.26 g paraformaldehyde (92% purity) was added slowly over about 10 minutes and the mixture was stirred at 60 ° C. for 8 hours. The reaction product was poured into isopropanol 1 with stirring and a precipitate was obtained.

The precipitate was collected by suction filtration, the nearly dry solid was dissolved in 1 of water, filtered, cooled with ice, and treated with an aqueous solution of 44 g of branched sodium dodecylbenzene sulfonate. The precipitate was filtered, recovered and air dried to obtain 43 g of high molecular weight diazo compound (3).

The resulting diazo compound (3) was treated as in Synthesis Example 1 and measured for GPC. As a result, about 10 mol% or more of the decamer was contained.

Example 1 An aluminum plate was immersed in an aqueous sodium phosphate solution for degreasing,
After polishing with a brush, electrolytic etching was performed, followed by anodic oxidation in sulfuric acid, and further immersion in an aqueous solution of sodium silicate for hydrophilic treatment.

The following photosensitive solution (1) was applied to this hydrophilized aluminum plate to obtain a photosensitive lithographic printing plate (1). The coating amount was 1.5 g / m ² .

Photosensitive liquid (1) However, the organic polymer compound (1) is a copolymer of p-hydroxyphenyl methacrylamide / 2-hydroxyethyl methacrylate / acrylonitrile / methyl methacrylate / methacrylic acid = 10/20/25/35/10 in a weight ratio. And the average molecular weight is 60,000.

For comparison, instead of the diazo compound of Synthesis Example 1, the condensation product of 4-diazodiphenylamine sulfate and paraformaldehyde in the molar ratio of n-dodecylbenzene sulfonate (this The molecular weight distribution of diazo resin
When measured by GPC, pentamer or less is 92 mol% of the whole
Met. ) Was used to prepare a photosensitive solution (a), and
Thus, a photosensitive lithographic printing plate (A) was obtained.

The obtained photosensitive lithographic printing plates 1 and A were exposed through a step wedge (increase in optical density in 0.150 steps) by a jet printer 2000 (Oak Seisakusho Co., Ltd.) for 50 seconds. Then, it was developed with the following developing solution-1 to obtain a lithographic printing plate.

As a result, the results shown in Table 1 were obtained.

The composition of Developer-1 is as shown below.

Developer-1 Further, when the storage stability of the photosensitive lithographic printing plates 1 and A was examined, the results shown in Table 2 were obtained. However, the storage stability in the table indicates that when stored in an atmosphere of 40 ° C and a humidity of 80%, the performance such as sensitivity, developing power, scumming, etc. changed compared to that immediately after the production of the photosensitive lithographic printing plate. It was judged to be unstable.

From the above results, it can be seen that the photosensitive composition of the present invention is remarkably superior to the conventional ones in sensitivity and storage stability.

On the other hand, when a photosensitive solution (b) was prepared using a diazo compound in which the counter anion of the diazo compound of Synthesis Example 1 was hexafluorophosphate, it was found that a precipitate was formed and it was not suitable for mass production. It was No precipitation occurred in Photosensitive solutions (1) and (a).

Example 2 A photosensitive solution (2) was prepared using the high molecular weight diazo compound (2) obtained in Synthesis Example 2, and a photosensitive lithographic printing plate (2) was obtained in the same manner as in Example 1.

Photosensitive liquid (2): However, the organic polymer compound (2) is a copolymer of 2-hydroxyethylmethacrylate / acrylonitrile / ethylmethacrylate / methacrylic acid = 43/12/40/5 in terms of weight ratio and has an average molecular weight of 110,000.

For comparison, a photosensitive solution (c) was prepared by using a diazo resin (4) instead of the high molecular weight diazo compound (2) of the photosensitive solution (2).
Was prepared. However, the above-mentioned diazo resin (4) is the same as Synthesis Example 2
At a molar ratio of 1: 1.2 of 4-diazo-4'-methoxydiphenylamine phosphate and paraformaldehyde.
It is the n-hexylbenzene sulfonate synthesized in.
The conditions for the condensation reaction are 0 ° C. and 2 hours. When the molecular weight distribution of this diazo resin (4) was measured by GPC, it was 85 mol% in 5 parts or less.

In the same manner as in Example 1, a photosensitive lithographic printing plate (C) was obtained from the photosensitive liquid (c).

The performance of the obtained photosensitive lithographic printing plates (2) and (C) was evaluated in the same manner as in Example 1.

On the other hand, instead of the high molecular weight diazo compound (2) of the photosensitive solution (2), sodium n-hexylbenzenesulfonate in Synthesis Example 2 was replaced with equimolar sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate. When a photosensitive solution was prepared using the high molecular weight diazo compound (5) synthesized by the method described above, a large amount of insoluble matter was generated and there was a problem in production. The solubility of the photosensitive liquids (2) and (c) was good.

From the above results, it can be seen that the photosensitive composition of the present invention has excellent sensitivity, storage stability and production suitability.

Example 3 A photosensitive solution (3) was prepared using the high molecular weight diazo compound (3) obtained in Synthesis Example 3.

Photosensitive liquid (3) However, here, the organic polymer compound (5) has a molar ratio of 4,
4'-diphenylmethane diisocyanate / 1,6-hexamethylene diisocyanate / 2,2-bis (hydroxymethyl) propionic acid = 60/40/100 polyadded to react polyurethane with ethylene bromohydrin It is a polyurethane in which a part of the carboxyl groups is hydroxyethylated. The average molecular weight measured by GPC was 45,000. The carboxyl group content was 1.20 meq / g.

For comparison, a photosensitive solution (d) was prepared by using a diazo resin (6) instead of the high molecular weight diazo compound (3). However, the diazo resin (6) is a branched dodecylbenzene sulfonate of a condensate in which the mixing ratio of 4-diazo-3-methoxydiphenylamine sulfate and paraformaldehyde is 1: 0.8 in molar ratio. The conditions of the condensation reaction were 20 ° C. for 2 hours, and the other conditions were the same as in Synthesis Example 3. When the molecular weight distribution of this diazo resin (6) was measured by GPC, the content of pentamer or less was 88 mol% of the whole.

The photosensitive liquids (3) and (d) were used as photosensitive lithographic printing plates (3) and (D) in the same manner as in Example 1 and the performance was evaluated in the same manner as in Example 1.

For further comparison, a high molecular weight diazo compound obtained by substituting equimolar potassium hexafluorophosphate for the branched sodium dodecylbenzenesulfonate in Synthesis Example 3 in place of the high molecular weight diazo compound (3) of the photosensitive solution (3). It was found that when using the resin (7), a precipitate was formed, which was a problem in production. There was no problem with the photosensitive liquids (3) and (d).

From the above results, it can be seen that the photosensitive composition of the present invention has excellent sensitivity, storage stability and production suitability.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiaki Aoi 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Shashin Film Co., Ltd. (56) Reference JP-A-59-78340 (JP, A) JP-A-SHO 61-91654 (JP, A) JP 62-59948 (JP, A) JP 47-5304 (JP, A) JP 61-252546 (JP, A) JP 59-222834 (JP, A) A) JP-A-62-169154 (JP, A)

Claims (1)

[Claims] 1. A photosensitive high molecular weight diazo compound represented by the following general formula [I], which comprises 20 mol% or more of compounds in which n in the general formula is 6 or more. A photosensitive composition comprising: (However, R ₁ ; methyl, methoxy, ethoxy or hydrogen atom, R ₂ ; methyl, methoxy, ethoxy or hydrogen atom, R ₃ ; lower alkyl (1 to 5 carbon atoms), lower alkoxy (1 to 4 carbon atoms) or Hydrogen atom, R; hydrogen atom, methyl or phenyl X; alkyl (6-18 carbon atoms) benzenesulfonate anion n; 1-200)