JPS58140299A - Treating liquid for making offset master hydrophilic - Google Patents

Abstract

PURPOSE:To obtain a treating liquid for making offset master hydrophilic, having a high preventiveness to ground staining, a high treating capacity, and excellent storage stability, using a hexacyano ferrate, an alkali metal or ammonium salt of phosphoric acid, and gluconic acid or its metal salt. CONSTITUTION:An objective treating liquid is obtained by mixing 5-50g/l (preferably) of a hexacyano ferrate (e.g., sodium ferrocyanate, etc.), 10-250g/l (preferably) of an alkali metal salt (e.g., sodium dihydrogen phosphate) or ammonium salt of phosphoric acid, and 0.2-50g/l (preferably) of gluconic acid or its metal salt (e.g., sodium gluconate, etc).

Description

[Detailed description of the invention] The present invention relates to a hydrophilic treatment liquid for offset masters.

In particular, the present invention relates to improvement of a hydrophilic treatment liquid for offset masters using an electrophotographic method.

Offset master sensitive material U produced by electrophotography, photoconductive powder such as zinc oxide and resinous binder such as silicone resin, acrylic resin, alkyd resin, etc. on a support such as metal, glass, or specially processed paper. It is obtained by coating and drying a crosstalk dispersion of and a solvent. The photographic method uses ``charging'' to impart a uniform charge to the sensitive material, and ``light exposure'' to leave a charge in the form of an image. dispersion liquid (can be used as a wet developer)
``Development'' by immersing in
It consists of a series of steps called "fixing" that promotes the fixation of liposensitive charged particles onto the sensitive material.

In addition to the wet-type image development method, there is also a dry-type development method. - For example, regarding the magnetic brush method, the following 1° pigments such as carbon black, thermoplastic resin, bamboo electric improver, etc. are kneaded and finely pulverized to form a toner, and this is mixed with iron powder. Arranged in +! The above mixture is drawn into a flat state by being attracted by a magnet.

Lightly touch this tip to the photosensitive material that has been exposed to light. 1) The toner is electrostatically adhered in the form of an image and developed. 3. Next, this 2 is heated to "fix" the entire surface. 1. Generally, a dry method is used. The image is fixed better than wet development, so the printing durability is high, and the plate-making machine is inexpensive and easy to maintain. Compared to the prints from the master produced by the plate-making machine used, the print quality, such as capri, fine lines, and halftone dot reproducibility, is currently considerably inferior. Plate making machines currently on the market.

Most of them use the wet method, and very few use the dry method.

In the offset master thus obtained, the non-image areas are chemically treated to make them hydrophilic, so that only the lipophilic areas of the lipophilic particles, which are the image areas, receive printing ink. In other words, a distinction between lipophilic and hydrophilic enzymes occurs only through the hydrolysis treatment.

Hydrophilic! The characteristics that a physical liquid should have are that it has sufficient hydrophilicity and hydrophilicity even in cases where the processing time is short and repeated processing is difficult, such as with a hydrophilic treatment machine built into an automatic printing machine. The ability of hydrophilic treatment does not deteriorate even with continuous treatment,
It is stable against light and heat for a long time, does not cause precipitation, and does not cause any deterioration in printing performance.When diluting the processing liquid and using it as dampening water during printing, the proportion of diluted water can be changed. In addition, it is possible to maintain high printing performance and obtain sufficient printing durability. ■] All K of high-quality masters made by sales plate-making machines
(Things that can be done for furnaces, etc.)

The above-mentioned treatment liquids currently on the market for the same purpose, as well as many formulations that have been proposed in the past, do not work as described above! ! A leopard water treatment solution that completely satisfies the requirements is extremely rare.

The purpose of the present invention is to improve the conventional drawbacks and provide a well-balanced hydrophilic treatment with respect to various properties that can fully meet the above requirements.
It is to provide L.

That is, the present invention provides a 141° hydration treatment liquid for an offset master using electrophotography, which is characterized by containing a hexacyanoferrate, a phosphate, and gluconic acid or a metal salt thereof. It can contain one or more of a polybasic acid salt, a parent, an aqueous polymeric substance, an alcohol, an oleating agent, and a preservative.

Although the mechanism of hydration according to the present invention has not been completely elucidated, zinc oxide in the non-image area of the photosensitive layer reacts with hexacyanoferrate and phosphate to make it hydrophilic and water-insoluble. It is thought that it generates a layer of material. Since the hydrophilic layer is gradually eroded during printing, the hydrophilic treatment liquid is diluted several times with tap water and used as a dampening solution to make the hydrophilic layer that is being eroded into a hydrophilic state that does not cause background stains or smudges. It must be maintained constantly. In this way, the hydrophilic treatment liquid must be designed taking into consideration not only the hydrophilic treatment process but also the ability of dampening water, which is usually used by diluting the hydrophilic treatment liquid.

Next, each component of the hydrophilic treatment liquid of the present invention will be explained.

Hexacyanoferrates General 2 M41 [FeII (ON
)6).

Mz”M2” [Fe■(ON)s], MIM station F
MIi, i Na, K
.

Li, NH4, R'b, Os, Ou
□), Mlld, Mg, Oa.

Sr, Ba, Ou, and III are A/, etc., and salts that are stable in the hydrophilic treatment solution can be used. Representative examples include sodium ferrocyanide, potassium ferrocyanide, sodium ferricyanide, and potassium ferricyanide.

The salt concentration in the processing solution is 1t/! ~100 f/A especially 5
A range of f/A to sof/# is preferable. It is also possible to use a mixture of two or more salts within this concentration range.

Phosphate 17. NaH2PO4, Na2HPO4, KH
2PO4° to 2HPO4, NH4H2PO4, (NH4
) 2HPO4 and other alkali metal or ammonium salts of phosphoric acid, etc., and the salt concentration in the treatment liquid is #″i2t/todzO
Ot/l, particularly preferably from 10 f/A to 250 f/l
It is within the range of I. It should be noted that two or more of the above phosphates F':L may be used in combination.

An appropriate amount of gluconic acid or its metal salt Vi is added in order to speed up the water treatment, increase plate number processing ability and power, and further increase photostability and thermal stability.

Glyconic acid or its metal salt has a low chelating ability, so it suppresses color development precipitation over time and during use, and maintains long-term etching ability. , which produce a synergistic effect several times higher than when each is added alone. In addition, when the hydrophilic treatment liquid of the present invention is diluted with water and used as a 1-1 dampening solution according to the normal usage method, it can be used to prevent staining of metal rollers of printing presses and to improve the quality of metal materials used in printing presses. It is effective in preventing rust. Furthermore, when printing with certain types of printing ink, conventional hydrophilic treatment liquids and dampening solutions sometimes cause blurring of lines.

In particular, red color inks cause noticeable bleeding.

The treatment liquid of the present invention has the advantage of being effective in preventing color bleed, and can be used with any printing ink. In addition, it has a pH adjustment and buffering effect that meets important parameters regarding the processing solution capacity.
As described above, gluconic acid or its metal salt has many functions, and the treatment liquid of the present invention containing this substance is extremely easy to use in practice and has high performance characteristics.

The metal salt of gluconic acid (06H1207) used in the present invention includes sodium gluconate [Na(OaH).

O7)], calcium gluconate [ca(06H+t
07)2 ], Google: Non-9' iron ([1) (tj'
e (, (EgHo 07 )t ), copper(II) gluconate [O+1(06HnOy)z ), lead gluconate [pb(a.

H1107)2], barium gluconate [Ba(Oa
Hu 0t)z), potassium gluconate CK (OaHo
Oy) :) etc.

Concentration of gluconic acid or its metal salt in the treatment solution: 110,
05 f/A ~20 [1f/Z, good tL<tJ:a
21/1~50t/! It is. The above-mentioned gluconic acid and its metal salts may be used alone or in a mixture of two or more.

The above are the main components of the hydrophilic treatment liquid of the present invention, and are used in appropriate combinations depending on the purpose, type of offset master, etc.

In addition to the above-mentioned main components, the hydrophilic treatment liquid of the present invention may optionally contain polybasic organic acid salts, water-receptive polymeric substances, alcohols, chelating agents, and at least 4-N preservatives. I can do it.

The present inventors previously discovered that a hydrophilic treatment solution containing a hexacyanoferrate, an alkali metal phosphoric acid, an ammonium salt, and a polybasic organic acid salt is similar to the hydrophilization treatment solution of the present invention. It was used at a press conference to demonstrate the effects of
). In the present invention, 1J, upper l! e main character of the present invention h
This polybasic salt can be contained along with ν1 min, and the pH buffering capacity can be improved to 4.

A specific example of the polybasic organic acids used in the present invention is 1j(lJH4)20204. Kx020a, KH
OzO2゜Na20202. NaHO202, KH
Oxalates such as O3J04, NH4H2P4.
Malonates such as NH404H504, (NH4)203H204, (NH4)204H404, NH404H5
04.

K2O4H404, KO4H504, 0a04H404
, Na204H404゜Na○4 H5O41MgO4
Succinates such as H404, Na04H304, K2O4
H204, K24H404+ NH4C4H304r
(NH404H504,0a04H204,0a(04
H304) Maleate salts such as 2, (NH4), HC! 6
H507, NH4H2O6H50,.

K3O4H507, K2O4H404, KH206H5
07* Citrate salts such as Mg3 (0@HsO7)z, (NH4)204H40g.

K2H404H406, K2O, H4011, NH4H
(1!4H40,.

NILHO4H406, Mg(HO4H406)2.
LiHO4H406゜Na204H406, KNa0
The salt concentration in the treatment solution is Q, 1 f/I with normal salts and acid salts such as tartrates such as 4H40an LLi104H40.
1. ~100? /It% preferably ilr/l~20
It is used in the f/l range. The above salts may be used alone or in combination of two or more. Among the above salts, alkali metal salts and ammonium salts are preferred.

Hydrophilic polymer substance #'i, as disclosed in Japanese Patent Publication No. 40-10508, is water-soluble and has protective colloidal properties, and has the effect of protecting and reinforcing the hydrophilic layer.

Hydrophilic polymer substances used in the present invention include gum arabic, sodium alginate, carboxymethyl cellulose or its sodium salt, polyacrylic acid, polymethacrylic acid, or their sodium salts, ammonium salts, etc. Concentration is 0.1 t/l, ~5
0 f/l, preferably it[15f/Z~5v/! It is also possible to use a mixture of two or more types within the range of . Particularly suitable are gum arabic, alkoxymethyl cellulose or their sodium salts.

Alcohols are mentioned in the text of Japanese Patent Publication No. 59-13702, and they have a wetting effect that lowers the surface tension of the processing solution and improves leakage, and include not only monohydric alcohols such as ethanol and inpropyl alcohol, but also glycerin. Polyhydric alcohols such as ethylene glycol and ethylene glycol may also be used. These can be used as co-solvents when adding certain preservatives to processing solutions, as will be shown later. The concentration in the treatment liquid is in the range of 0.5 f/A to 80 f/j, preferably 1 f/b to 40 f/I. Particularly suitable are inpropyl alcohol or glycerin.

As disclosed in Japanese Patent Publication No. 46-21244, the chelating agent is Hegisacyanoferrate d1. When exposed to light or heat during storage or use, it forms a bluish-green precipitate and ionic components necessary for hydrophilization are lost. . By adding a chelating agent, each ion can maintain equilibrium, which prevents the formation of precipitates.
This allows the hydrophilic ability to be maintained at a high level. It is well known that aminocarboxylic acid-based chelating agents are particularly effective, and phosphonic acid-based chelating agents and some of the above-mentioned polybasic organic acid salts also act as chelating agents, although their effectiveness is somewhat low. By appropriately adding a chelating agent, the effect of preventing precipitation can be dramatically improved.

Specific examples of the chelating agent used in the present invention are trans-cyclohexanediaminetetraacetic acid, diaminopropanol-4
Sodium, potassium, and ammonium salts of acetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, diaminopropanetetraacetic acid, iminodiacetic acid, nitrilotriacetic acid, nitrilotris (methylenephosphonic acid), etc. are sb
The concentration in the treatment liquid is in the range of ao1 f/A to 20 t/, preferably α1 f/I to 4 t/Z. In terms of performance and cost, sodium, potassium, and ammonium salts of ethylenediaminetetraacetic acid are particularly preferred.

The preservative is used as a dampening solution during printing to prevent mold from forming and growing in the dampening dish of a printing press equipped with a Molton type dampening water device.

Specific examples of the preservative used in the present invention include formalin, phenol, dehydroacetic acid, benzoic acid ester, and the 6-inteazolone compound described in Japanese Patent Application No. 56-142021.The concentration in the processing solution is (1001y/Z). ~1o
t/i is preferably in the range of o, 01f/I, to 1 t/Z. Among these, phenol or 5-inteazolone compounds are suitable, and 3-inteazolone compounds are particularly preferred from the viewpoint of safety and health, since they can be effective with a small amount compared to other preservatives. Further, when adding the 3-inchazolone compound, a portion of the alcohol can also be used as a solvent as described above.

As described above, the present invention achieves hydrophilic strength and speed sufficient for practical use, as well as long-term and environmental preservation properties, usage characteristics, and
This product has improved the dampening water performance, etc. in an extremely well-balanced manner. In other words, the present invention sufficiently exhibits its performance in the case of a master obtained by a plate-making machine system that is said to have relatively low printing durability, and in addition, the present invention can sufficiently exhibit its performance in the case of a master obtained by a plate-making machine system that is said to have relatively low printing durability. It is a hydrophilic treatment liquid that is extremely easy to use even for masters with particle images.

Furthermore, the hydrophilic treatment liquid containing gluconic acid or its metal salt of the present invention has the following effects.

(1) Does not cause background stains.

(2) High processing capacity and little liquid fatigue.

(3) Stable against light and heat and has good storage stability.

(4) When diluting the treatment liquid and using it as dampening water, the dilution rate can be increased (more moisture).

(5) Has anti-corrosion properties. That is, it will not rust even if it comes into contact with parts used in printing machines, such as copper, chrome-plated parts, aluminum, and iron.

(6) Although the chelating effect is weak, 2 KKDTA・2H
When used in combination with 20, it exhibits a remarkable chelating effect and improves sedimentation resistance.

(7) 1) Has H buffering properties.

(8) Less elution of printing ink.

(9) There is less dirt on the metal roll.

OQ Etching speed is improved.

As mentioned above, the hydrophilic treatment liquid of the present invention is suitably used for offset mastering by electrophotography, but it can also be used for offset mustarding of hand-drawn material on these photosensitive materials, or for use as an offset master for corrected books. It can be used even if it is difficult.

Hereinafter, the present invention will be explained in detail with reference to examples, but the present invention is not limited by these examples.

Example 1 A hydrophilic treatment liquid for an electrophotographic offset master was prepared using the following recipe.

Potassium ferrocyanide 6. Of Sodium Dihydrogen Phosphate! 11. Ov potassium gluconate distilled water Meanwhile, commercially available electrophotographic offset master plate making machine Ite
The paper plate obtained in step 5 was passed once through a commercially available etching processor containing a hydrophilic treatment solution with the above formulation, and then set in the printing machine. On the other hand, a liquid diluted with a volume ratio of 7 parts tap water was used.The printing ink used was red ink manufactured by Toyo Ink, and when printing 1000 sheets, 10
Printed matter of stable quality without any ink bleeding or staining was obtained up to 00 sheets. Furthermore, under the same conditions, 5 per day
We conducted a two-week usage test on the 0 version to determine the quality of printed matter.
When we observed the printing performance, we found that even in the second week, it was
1 It didn't change at all. During this time, the hydrophilic treatment solution and dampening solution were automatically replenished to the extent that they were not reduced.

Also, take the processing liquid r4j in a milky white translucent plastic container,
When the process liquid was kept on a desk in a typical living room and examined for changes in temperature over a three-month period, the color of the processing liquid gradually became greenish, and some bluish-green precipitate was observed, but the printing performance decreased. There was no. The pH was 43. Furthermore, in a three-month test, there was no dirt on the metal rollers of the printing press, and there was no rust or scale on the materials used in the printing press, such as iron, copper, plated chrome, and aluminum. I was not able to admit.

Comparative Example 1 A hydrophilic treatment solution was prepared in Example 1 except that 0.1 f of potassium gluconate was removed and replaced with the same liter of distilled water. When the same test as in Example 1 was conducted using this treatment liquid, no scumming was observed, but the sharpness of the letters was poor and there was some bleeding of the red ink. In addition, in a static test on a desk in a living room, the greenishness increased to the same extent, but
A blue-green precipitate was observed to have formed after two weeks.

pH was 4.2. During a three-month practical test, ink stains appeared on the metal rollers, and rust or scale formed on the iron, aluminum, and other materials of the printing press.

Example 2 A hydration treatment solution was prepared according to the following recipe.

Sodium ferrocyanide 201 Monosodium phosphate 6.0? gluconic acid
0152 Glycerin
4.62 Gum Arabic 0.6
f EDTA・2Na salt 0.5 f Distilled water 86.4 f 7 Rising water #''i, 1. Using a volume ratio of 10 parts tap water to 1 part hydration treatment liquid, prepare printing ink IrAM fan black, and further add master. When a test was conducted according to Example 1 except that PM313 (manufactured by Iwasaki Tsushinki) was used, printed matter with an image quality superior to that of Example 1 was obtained.The printing durability was 1
It was 000 pieces. In the standing room test, although the greenish coloration of the treated solution increased to the same extent, no crumbling (blue-green) precipitate was generated. Similar to Example 1, there were no problems during storage and in practical tests over 3 months.

The pH was 45. In the 50°C storage test, no precipitate formation l-1' was observed even after one month.

Comparative Example 2 In Example 2, gluconic acid was omitted, and the same amount of water was added instead to the treated solution. pH was 445. Example 2
When we conducted a similar test, we found that some of the gothic letters and dot shadows were so blurred. In a 50°C storage test, a blue-green precipitate was observed in 1111 days. Note that the staining of the printing press was at the same level as in Comparative Example 1.

Agent: Patent attorney (8107) Takashi Sasaki (and 3 others) (1st Procedural Amendment, 1982 37'J23, 1981 R1 Application No. 22804 Bow 2 Title of Invention: Hydrophilic Treatment Liquid for Offset Master 3, Person making the amendment (relationship with 'l'l'l'l'il'l
(520) Fuji Photo Film Co., Ltd. 7 Target of amendment ° "Detailed description of the invention" column 8, content of amendment 0 Specification 9, line 6 from the bottom, "(Patent Application 1982-)
J is corrected as "(Patent Application No. 57-9471) J.

Claims (1)

[Scope of Claims] 1) A hydrophilic treatment liquid for an offset master, comprising a hexacyanoferrate, an alkali metal salt or ammonium salt of phosphoric acid, and gluconic acid or a metal salt thereof. 2) Hexacyanoferrate concentration is 1 f/Z ~ 100t/
I, phosphate concentration is 217Z~500 W/j, and glyconic acid or its metal salt concentration is 0.0! M/lI~2
0 CL t/L, the M2 hydration treatment liquid according to claim (1). 3) The main ingredients are hexacyanoferrate, an alkali metal salt or ammonium salt of phosphoric acid, and gluconic acid or its metal salt, and further include polybasic organic acid salts, hydrophilic polymer substances, alcohols, chelating agents, and a preservative. 4) Hexacyanoferrate # degree is 1f/! ~100y/A
, the phosphate concentration is 2/! ~500? /l. and gluconic acid or its metal salt concentration Q, O! M'/!
The hydrophilic treatment liquid according to claim (3), which has a hydrophilicity of 200 f/I.