JP2001277691A - Offset printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing system, in which an ink supplying device is simplified and further an offset printing is possible without water supply by a dampening water supplying device. SOLUTION: This offset printing system executes printing without supplying a dampening water with emulsion ink including 39.8 to 69.8 wt.% of oil-based ink component mainly made of a colorant, a binder resin, and a vegetable oil and/or a mineral oil, 30 to 60 wt.% of an aqueous component, 0.1 to 5.0% of a higher alcohol and 0.1 to 3.0 wt.% of a non-ionic surface active agent with an offset printing machine equipped with a device 5 for supplying ink to a plate surface by utilizing 2 to 6 rollers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset printing method, and more particularly, it does not require a dampening solution supply device.
Further, the present invention relates to an offset printing method capable of simplifying an ink supply device of a printing press.

[0002]

2. Description of the Related Art Offset printing is a printing method using a flat printing plate having no unevenness. The ink used in this printing method is an oil-based ink, and the transfer of the ink onto the plate is controlled by utilizing the repulsion of water and oil. FIG. 1 is a conceptual diagram showing a device for supplying water and ink to a plate in a general offset printing press, and FIG. 2 is a conceptual diagram of a plate surface. On the plate (3), the image area 8 for transferring ink has a lipophilic and water-repellent surface, and the non-image area 9 for not transferring ink has a hydrophilic and oil-repellent surface. .

First, water called dampening water is supplied to the printing plate (3) by the dampening roller 1 of the dampening water supply device (1). At this time, the image area 6 repels the dampening water. As a result, the non-image area 7 is covered with dampening water. After that, the ink filled in the ink fountain 2 is
When the ink is supplied to the plate surface by an ink supply device (2) including an ink supply roller 3, an ink transfer roller, an ink mixing roller 4, and an inking roller 5, the ink is transferred to the non-image area 9 by the repulsion of water-oil. Instead, the image is transferred only to the image area 8.

[0004] In this way, the ink transferred to the image portion on the plate is further transferred to a blanket (not shown) and a printing medium (not shown), and the printing process is completed. Recently, in offset printing, machines with different ink supply devices have emerged. As typical ink supply methods, there are plunger pump method, digital pump method, and keyless method in addition to the bottle method. There is a problem that the number of rollers is increased (usually having seven or more rollers) and the size of a printing machine including the installation of a water supply device is increased, and power consumption for operating the huge equipment is increased.

[0005]

The problem to be solved by the present invention is to solve the above-mentioned problem, to simplify the ink supply device, and to further eliminate the water supply by the dampening water supply device. Another object is to establish a printing method that enables offset printing.

[0006]

In order to perform offset printing without using fountain solution, a method using an emulsion type ink is known. This uses an emulsifier to emulsify water in the oil-based ink component, and the mechanical stress applied while the ink is supplied to the plate surface,
The water and the oil-based ink component are separated so that the water covers the non-image area.

[0007] Therefore, in a state where no stress is applied, contradictory performances such that water is maintained in a stable emulsified state in the ink while the stress is applied are required to be contradictory to each other. Requires high accuracy.

Therefore, the present inventors have examined the relationship between the ink composition and the suitability for emulsification of water by using an ink supply device having various numbers of rollers, and have realized the configuration of the minimum ink supply device. The present invention has been completed by establishing an offset printing method that does not require the supply of dampening water.

That is, the invention according to claim 1 of the present application uses an offset printing machine provided with an apparatus for supplying ink to a printing plate using two to six rollers, and uses a colorant, a binder resin, a vegetable oil and / or a vegetable oil. Or 39.8-69.8% by weight of an oil-based ink component mainly composed of mineral oil;
30 to 60% by weight of an aqueous component, 0.1 to 5.0% of a higher alcohol represented by the following formula (1), and 0.1 to 3.0% by weight of a nonionic surfactant represented by the following formula (2) %
The present invention relates to an offset printing method characterized in that an emulsion ink containing is printed without supplying dampening water. The R1-OH (1) R2- O- (CH2-CH2-O-) n-H (2) ( saturated or unsaturated hydrocarbon group _{R 1} is in the range of 8 to 20 carbon atoms, _{R 2} is A saturated or unsaturated hydrocarbon group having a carbon number (k) in the range of 4 to 20;
Represents an integer in the range of 0. Also, k and n are 1.5n ≦ k ≦
6n. )

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an offset printing method according to the present invention will be described in detail.

The printing method of the present invention enables offset printing with a simplified ink supply device by using an emulsion ink obtained by emulsifying an aqueous component with an oil-based ink component by using a specific emulsifier. It is to be.

First, the oil-based ink component constituting the emulsion ink of the present invention may be the same as the usual offset printing ink comprising a colorant, a binder resin, a vegetable oil, a mineral oil and the like.

Accordingly, as the coloring agent used in the oil-based ink component, inorganic and organic pigments used in ordinary offset printing inks can be used. For example, inorganic pigments such as titanium dioxide, barium sulfate, calcium carbonate, carbon black, and azo pigments can be used. Pigments, lake pigments, phthalocyanine pigments,
Organic pigments such as isoindoline pigment, anthraquinone pigment and quinacridone pigment can be exemplified.

As the binder resin used in the oil-based ink component, a resin component used in a usual offset printing ink can be used, and rosin-modified phenol resin, various alkyd resins, petroleum resin, rosin ester resin, polyester resin, Gilsonite or a modified product thereof can be given. These resin components may be gelled using a gelling agent.

The vegetable oil and mineral oil used in the oil-based ink component include, for example, vegetable oils such as soybean oil, cottonseed oil, linseed oil, safflower oil, tung oil, tall oil, dehydrated castor oil, canola oil, and n-paraffin. Solvent, isoparaffin solvent, naphthene solvent, aromatic solvent, α-olefin solvent, spindle oil, machine oil, cylinder oil,
Mineral oils such as light oil, turpentine oil, and mineral spirit can be mentioned.

Furthermore, organic solvents (excluding higher alcohols represented by the following formula (1)) used in general offset printing inks, pigment dispersants, drying retarders, antioxidants, backing Various additives such as an inhibitor (however, excluding a nonionic surfactant represented by the following formula (2)) can be appropriately used.

The viscosity range of the oil-based ink component is preferably from 1 to 10 pa · s, and the content of each of the above materials is such that the colorant 1
The suitable range is 0 to 30% by weight, 10 to 45% by weight of a binder resin, 0 to 60% by weight of vegetable oil, and 0 to 60% by weight of mineral oil.

Next, in the emulsion ink used in the present invention, in order to emulsify an aqueous component in an oil-based ink component, a higher alcohol represented by the following formula (1) and a non-ionic alcohol represented by the following formula (2) are used. A surfactant is used as an emulsifier. The R1-OH (1) R2- O- (CH2-CH2-O-) n-H (2) ( saturated or unsaturated hydrocarbon group _{R 1} is in the range of 8 to 20 carbon atoms, _{R 2} is A saturated or unsaturated hydrocarbon group having 4 to 20 carbon atoms (k);
Represents an integer in the range of 0. Also, k and n are 1.5n ≦ k ≦
6n. )

The higher alcohol represented by the general formula (1) includes, for example, nonyl alcohol, lauryl alcohol, tridecanol, cetanol, stearyl alcohol, isostearyl alcohol, oleyl alcohol and the like.

The nonionic surfactant represented by the above general formula (2) includes n moles (however, with respect to a saturated or unsaturated alcohol having a carbon number (k) in the range of 4 to 20). 1.5n ≦ k ≦ 6n) Compounds obtained by adding ethylene oxide, for example, polyoxyethylene alkyl phenyl ethers such as ethylene oxide adduct of nonylphenol, ethylene oxide heavy compound of octyl phenol, and lauryl alcohol Examples thereof include polyoxyethylene alkyl ethers such as ethylene oxide polyadducts.

Next, as the aqueous component used in the emulsion ink used in the present invention, only water such as ion-exchanged water and distilled water may be used, or a water-soluble organic solvent such as polyhydric alcohol may be blended. In addition, there is no problem even if a dampening solution used conventionally is used.

As a method for producing an emulsion ink using the above-mentioned materials, the following steps (1) to (4) are generally performed.

Resin varnish, colorant, vegetable oil, mineral oil,
The base for offset printing ink is obtained by dispersing the pigment dispersant in a bead mill or a three-roll mill if necessary.

In the offset printing ink base,
Add a resin varnish or other additives that can be used as needed, adjust the viscosity with vegetable oil, mineral oil, etc., add the higher alcohol specified in the present invention and a nonionic surfactant, and add an emulsifier. An oil-based ink component is obtained.

An aqueous component containing water as a main component is added to the offset printing composition and stirred to obtain a final emulsion ink for offset printing.

Further, the amounts of the oil-based ink component, the aqueous component, the higher alcohol and the nonionic surfactant contained in the emulsion ink for offset printing are 39.8 to 6 based on the total amount of the emulsion ink.
9.8% by weight, 30 to 60% by weight of aqueous component, 0.1 to 5.0% of higher alcohol, and 0.1% of nonionic surfactant.
1 to 3.0% by weight.

If the content of the aqueous component is smaller than the above range, the problem that the ink is transferred to the non-image area of the plate and the printed matter is stained occurs. , The stability of emulsification is reduced, and stable ink supply becomes difficult.

If the content of the higher alcohol is less than the above range or the content of the nonionic surfactant is more than the above range, the oil-based ink component and the aqueous component cannot be sufficiently separated, There is a problem that the ink is transferred to the non-image area of the plate and the printed matter is stained. On the other hand, when the content of the higher alcohol is larger than the above range or the content of the nonionic surfactant is smaller than the above range, the emulsification of the aqueous component becomes unstable, and the aqueous component between the rollers becomes unstable. Even if separation occurs early, and even if no stress is applied, the aqueous component is separated over time, so that printability cannot be obtained.

In the emulsion ink, the separation between the oil-based ink component and the aqueous component is caused by the mechanical stress applied from the ink fountain to the plate surface when the ink is supplied. The composition will be different.

Therefore, when designing the emulsion ink used in the present invention, the higher alcohol and the emulsifier for the nonionic surfactant are simply increased or decreased according to the content ratio of the oil-based ink component and the aqueous component. Rather, it is desirable to adjust the content of the oil-based ink component, the aqueous component, the higher alcohol, and the nonionic surfactant in accordance with the intensity of the mechanical stress applied when the ink is supplied to the plate. .

The emulsion ink obtained from the above materials and the production method is printed by an offset printing method.

The emulsion ink receives mechanical stress due to the roller nip while being supplied from the ink fountain to the plate surface, and is separated into an oil-based ink component and an aqueous component.

The emulsion ink used in the present invention can be used to quickly convert the oil-based ink component and the aqueous component even when using an ink supply device having six or fewer rollers and a smaller number of rollers than a conventional printing machine. Separation occurs and offset printing is possible without supplying dampening water.

If the conditions such as the shearing speed of the rollers and the contact pressure are set so that sufficient mechanical stress is applied to the ink, the dampening solution can be supplied even if only a minimum of two rollers are used. Offset printing is possible without performing.

Further, the present invention can be applied to a doctor type keyless printing press, and according to the present invention, an offset printing method which does not require a dampening water supply device and can further simplify the ink supply device of the printing press. Can be established.

[0036]

EXAMPLES Hereinafter, offset printing in a doctor type keyless machine having 2 to 5 rollers from an original roll to inking will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these as long as it does not deviate from the applicable range. In the following description, “parts” indicates parts by weight.

[0037]

[Manufacture of varnish for ink for offset printing]

<Production of rosin-modified phenol resin varnish> In a four-necked flask equipped with a condenser, a thermometer, and a stirrer, 30 to 40 parts of a rosin-modified phenol resin (manufactured by Hitachi Chemical Polymer: acid value 20, softening point 162 ° C). 20 to 40 parts of soybean oil, No. 6 solvent (Nippon Petrochemical Co., Ltd.)
20-40 parts, and gelling agent ALCH 1-3 parts (manufactured by Kawaken Fine Chemical Co., Ltd.), and heated to 230 ° C. 3
After stirring for 0 minutes, the mixture was stirred at 175 ° C. for 30 minutes to obtain a rosin-modified phenolic resin varnish.

<Production of Gilsonite Varnish> Gilsonite Select (American Gilsonite Co., Ltd.) was placed in a four-necked flask equipped with a condenser, a thermometer, and a stirrer.
15 parts, 5 parts of ER resin, and 80 parts of No. 6 solvent, and the mixture was heated to 140 ° C. and stirred at the same temperature for 4 hours to obtain a Gilsonite varnish.

<Production of Petroleum Resin Varnish> Condenser,
In a four-necked flask equipped with a thermometer and a stirrer, 55 parts of maleated petroleum resin (manufactured by Nippon Oil), No. 6 solvent 4
After charging 5 parts and heating to 140 ° C., the mixture was stirred at the same temperature for 30 minutes to obtain a petroleum resin varnish.

[0041]

[Production of ink composition for offset printing]
8, Comparative Examples 1 to 7 40 parts of rosin-modified phenol resin varnish, 12 parts of Gilsonite varnish, 12 parts of petroleum resin varnish, 20 parts of carbon black # 32 (manufactured by Mitsubishi Chemical Corporation), and 1 part of anti-drying agent The mixture was kneaded with a bead mill to obtain a black ink base.
Next, with respect to the black ink base, a higher alcohol, a nonionic surfactant, a petroleum resin varnish,
No. 6 solvent is added and diluted to obtain a viscosity of 2.0 to 6.0P.
a · s ink composition for offset printing,
Each of the ink compositions for offset printing obtained above and water were stirred and mixed so as to have the composition shown in Table 1, and Examples 1 to 8,
Emulsion ink compositions for offset printing of Comparative Examples 1 to 7 were obtained.

[0042]

[Performance evaluation test] (1) Printing test Offset printing was performed under the following printing conditions using the emulsion ink composition for offset printing obtained in the example.
The fluidity of the emulsion ink in the ink pan, the stability of the emulsion ink in the pan, the emulsification stability between rollers, the emulsification stability when passing through a doctor, and the separation of water from the plate were examined. Table 2 shows the performance evaluation results.

The fluidity of the emulsion ink in the ink pan was evaluated as 3 when the fluidity of the emulsion ink in the ink pan was 2, 2 when the fluidity was a little fluid, and 1 when the fluidity was not.

The stability of the emulsion ink in the bread was evaluated as 3 when the emulsion ink in the bread had stability, 2 when the stability was somewhat stable, and 1 when the stability was not stable.

With respect to the emulsification stability between the rollers, the water separation between the rollers was evaluated as 3 when no water separation was performed, 2 when slightly water separation was performed, and 1 when water separation was performed.

With respect to the emulsion stability upon passing through a doctor,
Regarding water separation at the time of passing through the doctor, the water separation was evaluated as 3, the water separation was performed as 2, and the water separation was performed as 1.

In the water separation on the plate, the water separation on the PS plate was evaluated from the paper obtained as a result of printing. The non-image area was evaluated as 3 without stain, 2 as slightly stained, and 1 as stained.

(Printing conditions) Printing machine: blade-type keyless machine. Plate material: PS plate Paper: Newspaper Printing speed: 24,000 parts / hour-140,000 parts / hour The number of rollers from the original roll to the inking is 2-5.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

The emulsion ink used in the present invention can be applied to a keyless offset printing press having a smaller number of rollers, further eliminating the need to supply dampening water, simplifying the printing press, and improving economic efficiency. It is possible to establish a very excellent offset printing method.

[0052]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a device for supplying water and ink to a plate in a general offset printing press.

FIG. 2 is a conceptual diagram of a printing plate.

[0053]

[Description of Signs] 1 Watering roller 2 Ink fountain 3 Ink fountain roller 4 Ink transfer roller, ink kneading roller 5 Ink applying roller 6 Image area whose surface is exposed by repelling dampening water 7 Covered with dampening water Non-image area 8 Image area with ink transferred 9 Non-image area covered with fountain solution (1) Fountain solution supply device (2) Ink supply device (3) Plate surface

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoichi Kojima 1-23-23 Edobori, Nishi-ku, Osaka-shi F-term in Sakata Inx Corporation (reference) 2H113 AA01 BA06 BC00 BC01 BC02 BC09 BC10 DA03 DA07 DA10 DA53 DA57 DA60 EA10 4J039 AB04 AB06 AB08 AB10 AD18 AE02 AE06 AF01 BA04 BA30 BA35 BC07 BC13 BC17 BC39 BC53 BC60 BE22 CA06 EA48 GA02

Claims (1)

[Claims] An offset printing machine equipped with a device for supplying ink to a printing plate using two to six rollers,
Oil-based ink components 39.8 to 69 mainly composed of a colorant, a binder resin, a vegetable oil and / or a mineral oil.
8% by weight, 30 to 60% by weight of aqueous component, 0.1 to 5.0% by weight of higher alcohol represented by the following formula (1), and 0.1 of nonionic surfactant represented by the following formula (2)
An offset printing method characterized by printing an emulsion ink containing up to 3.0% by weight without supplying dampening water. The R1-OH (1) R2- O- (CH2-CH2-O-) n-H (2) ( saturated or unsaturated hydrocarbon group _{R 1} is in the range of 8 to 20 carbon atoms, _{R 2} is A saturated or unsaturated hydrocarbon group having 4 to 20 carbon atoms (k);
Represents an integer in the range of 0. Also, k and n are 1.5n ≦ k ≦
6n. )