JP2003191660A - Condensed dampening water additive for lithographic printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dampening water additive, which is not controlled by law on industrial safety and hygiene and ordinance on organic solvent poisoning prevention, apply to the present device in use (or a dampening water circulating device), with which a high quality printing can be easily attained, instead of a conventional additive in which approximately 10 wt.% of isopropyl alcohol specified as a second type organic solvent under the law is added to tap water and an additive called etching liquid is further added in offset printing. <P>SOLUTION: This condensed dampening water additive for lithographic printing consists of a mixture of t-butyl alcohol and solvent compatible with the t-butyl alcohol. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fountain solution additive for lithographic printing plates, and more specifically, it does not contain conventionally used isopropyl alcohol and does not cause stains or various troubles on printed matter. Boiled water concentrate additive.

[0002]

2. Description of the Related Art Lithographic printing is a printing method that takes advantage of the property that water and oil are essentially immiscible. The printing plate surface consists of a region that receives water and repels oily ink and a region that receives oily ink and repels water. The former is a non-image region and the latter is an image region. That is, lithographic printing is a printing method that utilizes mutual repulsion between dampening water and ink, deposits dampening water on the non-image area and ink on the image area, and prints.

From the 1970s, the dampening water supply system was gradually changed from the intermittent water supply system to the continuous water supply system, and as of 2000,
Most newly produced printing machines are of continuous water supply type. Along with this, the performance requirements for dampening water have increased, and in addition to the functions such as the conventional surface conditioning effect, antiseptic effect, and pH adjustment,
Evaluation based on Fountain Solution Efficiency (FSE) has become important. What is the dampening liquid efficiency? Proposed by R. Bassemir et al. Of Sun Chemical Co. in order to quantitatively express the functional efficiency of the dampening water on the printing machine, and it is currently a generally accepted index in the printing industry. Is.

The humidifying liquid efficiency (FSE) is defined by the following equation. Humidifying liquid efficiency (FSE) = Dynamic surface tension of distilled water / Viscosity of distilled water-Dynamic surface tension of dampening water (S) / Viscosity of dampening water (V) Viscosity of distilled water at 20 ° C = 1 cps and dynamic surface tension of distilled water = 72.8 dynes / cm, so the above equation is simplified to the following equation. FSE = 72.8- (S / V) If the dynamic surface tension is low and the viscosity is high, the transfer efficiency of the dampening water is higher, so the smaller the S / V in the formula, the higher the efficiency of the dampening water. The higher the efficiency of the dampening water, the higher the FSE
Indicates that the value of becomes large.

[0005] Conventionally, in order to obtain highly efficient dampening water, about 10% by weight of isopropyl alcohol (IPA) is added to tap water, and an additive which is called an etchant is used for surface conditioning, antiseptic, pH adjustment, etc. Has been used.

However, isopyr alcohol is designated as a second type organic solvent in the Industrial Safety and Health Act / Organic solvent poisoning prevention regulations, and when used at a concentration of 5% by weight or more, ventilation equipment,
Measures such as work environment measurement and health check of workers must be taken.

Therefore, ethylene glycol ether,
Other than propylene glycol ether, a water-soluble high-boiling solvent added to the etchant, for example, JP-A-10-337975.
There are proposals such as Japanese Patent Laid-Open No. 10-337975, Japanese Patent Laid-Open No. 6-206391, Japanese Patent Laid-Open No. 5-112085.

[0008] These are expected to have the functions of surface conditioning, antiseptic, pH adjustment and surface tension reduction with one liquid, but at the site of use they are adjusted depending on the water supply mechanism of the printing machine, the water quality, and the environment (temperature, humidity). The surface / antiseptic / pH adjusting function and the required amount of surface tension reduction do not necessarily match. In order to manage this with one liquid, it is forced to create a complicated management standard and causes printing trouble.

Further, JP-A-6-183171 proposes an IPA substitute additive in which a propylene glycol ether solvent is added separately from the etchant.

In actual use, the dampening water is controlled by a circulation addition device, and the addition method is pH or quantitative addition for the etchant, and specific gravity control for additives such as IPA. However, the physical properties of the above-mentioned proposed additives cannot be controlled by the existing equipment. Therefore, the above IPA substitute additive is not suitable for practical use and cannot be a concrete measure for IPA reduction.

[0011]

The object of the present invention is not restricted by the Industrial Safety and Health Act and the organic solvent poisoning prevention rules, and is applicable to the current device (fountain solution circulation device), which facilitates high-quality printing. It is to provide a fountain solution additive that can be achieved.

[0012]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that the above-mentioned object can be easily achieved by using the following fountain solution concentrated additive for lithographic printing. The inventors have found that they can be achieved and achieved the present invention. That is, the present invention is a fountain solution concentrated additive for lithographic printing comprising a mixture of t-butyl alcohol and a solvent having compatibility with t-butyl alcohol.

The solvent compatible with t-butyl alcohol used in the present invention includes a solvent which is dissolved in t-butyl alcohol by about 5 to 50%.

Specific examples of the solvent having compatibility with t-butyl alcohol include n-propyl alcohol, n-pentyl alcohol, 2-methyl-1-butanol, 2,2-dimethyl-1-propanol and 2 -Alcohols such as pentanol, 3-pentanol, 3-methyl-2-butanol, ethylene glycol mono n-propyl ether, ethylene glycol mono t-butyl ether, diethylene glycol mono n
-Butyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl, propylene glycol mono n-propyl ether, propylene glycol mono n-
Polyhydric alcohol ethers such as butyl ether, propylene glycol monoisobutyl ether, dipropylene glycol monomethyl ether dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol isobutyl ether, ethylene glycol, propylene glycol, butylene glycol, glycerin, etc. Polyhydric alcohol, 3-
Methoxy-3-methylbutanol and water. At least one of these compounds can be added to t-butyl alcohol for use. However, when a compound having a large specific gravity difference with t-butyl alcohol (specific gravity of 0.9 or more) is used, it is necessary to perform mixing within a controllable specific gravity range in a dampening water additive addition device by specific gravity management.

Of the above compounds, preferably n-propyl alcohol, n-pentyl alcohol, 2-methyl-1-butanol, 2,2-dimethyl-1-propanol, 2-pentanol, 3-pentanol, 3 -Methyl-2-butanol, t-pentyl alcohol, propylene glycol mono-n-butyl ether and water.

More preferably, when considering industrial use,
It is water. At present, an azeotropic mixture of t-butyl alcohol and water is used as a reaction solvent. This can be used as a fountain solution concentrated additive for lithographic printing, and the cost can be significantly reduced as compared with a mixture with another solvent. Also, the azeotropic mixture of t-butyl alcohol and water is more efficient than isopropyl alcohol.

When a mixture of t-butyl alcohol and water is used as a fountain solution concentrated additive for lithographic printing, the proportion of t-butyl alcohol is preferably 70 to 95% by weight based on the total amount.

Although there is a problem in cost, n-propyl alcohol, n-pentyl alcohol, 2-methyl-1-butanol, 2,2-dimethyl-1-propanol, 2-pentanol, 3-pentanol , 3-methyl-2-butanol, t-pentyl alcohol, propylene glycol mono-n-butyl ether by adding at least one compound selected from the azeotropic mixture of t-butyl alcohol and water. A highly efficient fountain solution concentrated additive for lithographic printing can be obtained.

The proportion of t-butyl alcohol in the fountain solution concentrated additive is preferably 20 to 95% by weight, more preferably 50 to 95% by weight, based on the total amount.

In use, the fountain solution concentrate additive of the present invention is added with water and used as a diluent. At that time, the dilution concentration of the concentrated additive is preferably 1 to 20% by weight, and more preferably 2 to 15% by weight.

[0021]

The present invention has the following effects. 1. Do not use IPA, which is regulated by the Industrial Safety and Health Act and the organic solvent poisoning prevention rules. 2. The dynamic surface tension can be reduced to more than IPA, and the effects such as reduction of printing trouble and reduction of addition amount can be obtained. 3. Current equipment (fountain solution additive addition device with specific gravity control)
Can be used as before.

[0022]

The present invention will be described in more detail with reference to Examples. In addition,% shows weight%. Examples 1 to 5 and Comparative Examples 1 to 2 Test method Printing plate is VS (Fuji Photo Film Co., Ltd. positive type PS
Version), FNS-A (Negative type P manufactured by Fuji Photo Film Co., Ltd.)
S version), LP-N (Fuji Photo Film Co., Ltd. photopolymer CTP (Computer to Plate) version), 830 Plate (Kodak Polychrome Japan Co., Ltd. thermal CTP version)
The printing plate prepared by preparing a solid part and a halftone dot portion of 5 to 95% (5% step size) by the usual plate making method was tested under the following printing conditions. Printing machine: Heidel Speedmaster SM102 (sheet-fed offset printing machine manufactured by Heidelberg Co., Ltd.) Printing speed: 10,000 sheets / hour Paper: Mitsubishi Pearl Coat A 66.5k Water supply mechanism: Alcolor fountain solution circulation machine: Technotrans (control of additive specific gravity) ) Additive control concentration: 5% (Circulating machine setting) Temperature and humidity: 20-22 ° C, 40-50% RH Ink: GEOS-E ink (manufactured by Dainippon Ink and Chemicals, Inc.) Number of copies: 20,000

[Table 1]

Table 2 shows the dynamic surface tension, the viscosity and the dampening liquid efficiency (FSE) when the dampening water additives of Examples and Comparative Examples were added to tap water. In all of the examples, good values were obtained as compared with IPA (Comparative Example 1).

[Table 2]

The printability and the suitability for the circulator were investigated. The results are shown in Table 3. Minimum water source dial value: Continuous (10,0
The minimum value of the Mizumoto dial that can be stably printed on (00 sheets) was calculated. The value on the water source dial indicates the amount of dampening water supplied. In the case of the Heidel Speedmaster SM102, the value of the water source dial is in the range of 0 to 100. The smaller the value, the smaller the supply of dampening water, and the larger the value, the larger the supply of water. b. Emulsifying property: When 10,000 sheets were printed with the minimum water-based dial value obtained in a, the printing machine was stopped, and the emulsified state of the ink on the ink kneading roller was investigated. Good A Bad B Bad C c. Bleedability: The minimum water source dial value found in a is 10,000
After printing one sheet, the printing machine was stopped and the extent to which the ink in the image area bleeds into the non-image area was investigated. Good A Somewhat bad B Bad C d. Circulator adaptability: 100,0 with the minimum water source dial value found in a
After printing 00 sheets, the printing machine was stopped, the dampening water of the water boat was sampled, and the additive concentration was measured by GLC (gas chromatographic analysis method). Chi deviation from the added set concentration of the circulator was investigated. Chi separation rate ± 5% or less A Chi separation rate ± 5 to 20% B Chi separation rate ± 20% or more C As a result of an investigation on printability of this example, (a) minimum amount of rise (drainage dial), ( Excellent results were obtained in all of b) emulsifying property, (c) bleeding property, and (d) circulatory machine adaptability, and good printed matter was obtained.

[Table 3]

Claims (2)

[Claims] 1. A dampener for lithographic printing comprising a mixture of t-butyl alcohol, a solvent having a compatibility with t-butyl alcohol and water, the addition ratio of water being 5 to 30% by weight based on the total amount. Water concentrated additive. 2. A mixture of t-butyl alcohol and water,
A dampening water concentrated additive for lithographic printing, which has an azeotropic composition in which the proportion of water is 13% by weight based on the total amount.