JPS62144950A - Plate making through brush painting of offset printing plate - Google Patents

Abstract

PURPOSE:To make a plate through drawing of images such as characters on an offset printing plate using a painting brush and prepare a marker which enables operation to be carried out more efficiently in printing with the plate through a series of works to obtain an expected finish of printing by using a water paint containing an organic high polymer emulsion obtained through emulsification polymerization, a viscosity improver and a painting improver as main components. CONSTITUTION:A marker to be brush-painting on an offset printing plate uses an organic high polymer emulsion obtained through emulsification polymerization such as synthetic latex and synthetic resin emulsion. Of these, the latex for paper coating and fiber processing having a viscosity of 100cp or less and 40-50% of solid contents is a desirable choice because of comparatively low viscosity, high concentration and high stability with time. To control adhesive property without impairing the characteristics of organic high polymer emulsion, colloidal silica is added as a viscosity improver. Further, to accelerate drying after brush painting with the marker a lower alcohol which can be well blended with latex is added as a painting improver. The marker has both high brush painting workability and high printability.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention is applied to the field of plate making, in which when making a master plate for offset printing, a brush is drawn directly onto the plate surface, and when it dries, it becomes a printed image. Paints used in (
(hereinafter referred to as a marker), and is intended to meet the demand for improving the workability of the marker.

(In) Prior art The offset printing original plates currently used in the field of light printing include (1) a direct printing type in which an image-receiving layer is provided on a water-resistant support, and (2) one on a water-resistant support. Examples include (3) an electrophotographic type in which a photoconductive layer (image-receiving layer) is provided, and (3) a silver salt photographic type in which a silver halide emulsion layer is provided on a water-resistant support. Electrophotographic and silver halide phototypes are made using the photographic method using the respective plate-making machines from the standard manuscript, while direct drawing and electrophotographic types are made using RPC, word processors, and hand-drawn without the need for a block. Usually, the plate is made directly by a method such as a printer.

Recently, supermarkets, retail stores, etc. have started using POP advertising (Point of Purch) to promote in-store sales.
AseAdvertlseIlent) is becoming more and more common. POP advertisements depict product names, prices, etc. in bright colors to attract people's attention, and are often created by printing. That is, the above content is hand-drawn using magic ink, a marker, etc., directly onto an offset printing original plate, and printed in a flashy color such as red.

Commercially available magic ink has a character width of only about 10 mm at most, so if you need thicker characters, you will have to rely on brush strokes.

Therefore, conventionally, commercially available solvent-based or water-based paints have been used as they are or diluted as markers for brush drawing. However, in the case of solvent-based markers, the marker on the brush hardens immediately after painting, making it extremely difficult to handle. Water-based markers also have various disadvantages, such as poor spreadability of markers, difficulty in drying drawn letters, insufficient desensitization and printing fading, and peeling of text, making it impossible to print. .

For this purpose, the present inventors invented a water-based marker in which a brushability improver such as a lower alcohol was added to an organic polymer emulsion that had previously been emulsion polymerized (Japanese Patent Application
-127669) It is effective.

However, after drawing with a brush and drying, some of the adhesiveness of the marker remains, so when the original printing plates are stacked, they stick to each other (hereinafter referred to as blocking), which causes a problem that further improvements have been desired. .

(C) Purpose of the Invention The purpose of the present invention is to further improve workability through a series of operations in which images such as characters are made by brush-drawing on an offset printing original plate and printed with this to obtain the desired print finish. The purpose is to create markers.

In other words, a good marker suitable for plate making is one that (1) draws smoothly like ink and the brush can be washed with water, (2) dries quickly after drawing, and (3) does not make the drawn characters oil-sensitized. (4) Characteristics such as: (4) less adhesiveness of drawn characters, etc., and no blocking even when stacked.

(D) Structure of the Invention The inventors of the present invention have carefully studied the workability and printing quality of a series of plate-making operations to obtain the desired POP advertisement print by brush-painting on an offset printing original plate. We were able to successfully develop a water-based marker with significantly improved washability, drying properties, printing durability, and adhesion.

The markers that are brushed onto the offset printing plate are solvent-based,
Although water-based brushes can be used together, it is preferable to use water-based brushes in consideration of washability of brushes, overall ease of use in the working environment, etc. However, offset printing plates generally have a structure that prevents moisture from penetrating into the paper from the plate surface.
Most of the moisture removal or evaporation must occur from the surface of the plate. If the evaporation rate is slow, it is very important to increase the evaporation rate, such as by leaving the paint for a longer time after painting with a brush, or by drying the surface with a hair dryer, as this will reduce workability. It is also necessary to immediately form a film on the dried marker and sensitize it at room temperature. It is also necessary to have printing durability during printing.

For these purposes, an emulsion-polymerized organic polymer emulsion is used as a marker component in the present invention; however, as the emulsion-polymerized organic polymer emulsion, styrene-butadiene copolymer; styrene-butadiene-acrylic acid ester copolymer may be used. ; Polybutadiene polymer; Acrylonitrile-butadiene copolymer; Polyvinyl acetate polymer; Ethylene-vinyl acetate copolymer; Polyacrylic acid ester polymer; Polymethacrylic acid ester polymer; Polyethylene polymer; Vinyl chloride copolymer Synthetic latex and synthetic resin emulsion consisting of the following components can be used.

Among these, the viscosity is 100 cp or less and the solid content is 40 to 5.
Latex for paper coating and latex for fiber processing with a concentration of about 0% are particularly preferred because they have relatively low viscosity, high concentration, and good stability over time.

The film-forming properties of organic polymer emulsions vary depending on the film-forming temperature (MFT) of each polymer compound, but if the MFT is below room temperature, the viscosity is low and the drawn characters will be It spreads well thinly and uniformly, and has a high concentration, so water evaporates quickly. Film formation occurs simultaneously with the removal of water, resulting in oil sensitivity (affinity for printing ink). When this is printed using an offset printing machine, printing durability and the desired print finish can be obtained. That is, in order to form a film at room temperature and have printing durability, it is necessary to select a film with an MFT of 25° C. or lower.

However, after a marker made of an organic polymer emulsion with a MF of 725°C or less is applied with a brush and dried, some stickiness remains, and if the surrounding temperature happens to be high when the brush-drawn original printing plates are piled up, this stickiness causes There was a problem of mutual blocking. As a result of repeated experiments, the present inventors have found that colloidal silica is effective as an additive, ie, a tack improver, for suppressing tackiness without impairing the properties of organic polymer emulsions.

The colloidal silica used in the present invention has good compatibility with latex, has the property that the mixed liquid does not separate or precipitate, and is often supplied with a solid content of 20 to 40%. The amount added is organic polymer emulsion (solid content)
In contrast, colloidal silica (solid content) is preferably 10 to 200%. If the amount of colloidal silica is less than this, stickiness remains and blocking is likely to occur, and if it is more than this, the concentration becomes thin and difficult to handle.

Furthermore, as a brushability improving agent for hastening drying after marker brushstrokes, it is desirable to add lower alcohols that mix well with latex. Among them, alcohols with low boiling points such as methanol; ethanol; n-propatol; The rate of evaporation is extremely fast, so
Particularly preferred.

Furthermore, the marker of the present invention can be made easier to see with the naked eye even after being painted with a brush by adding a coloring agent with good affinity.

(E) Example The present invention will be explained in more detail by way of examples.

Example 1 A marker having the following composition was prepared.

〔marker〕

JSR-069240 parts (synthetic latex manufactured by Japan Synthetic Rubber ■, solid content 40%, MPTO °C or less, styrene-butadiene copolymer) Snowtex 0 20 parts (colloidal silica manufactured by Nissan Chemical Industries ■, solid content 20%) Methanol 5 Part Pilot Ink (M) Part 1 When I drew the POP advertisement content on Mitsubishi Straight Master (direct-drawing type offset printing original plate manufactured by Mitsubishi Paper Corporation) with a watercolor paintbrush,
The brush drawing properties, drying properties, and washability of the brush were extremely good, and there was almost no stickiness after drying, and no blocking occurred even when the masters were stacked.

In addition, the printing machine is Gestellatner-339 (fully automatic offset printing machine manufactured by Gestellatner), the printing ink is Nini Champion FC Kinaka (manufactured by Dainippon Ink & Chemicals), and the etchant is Gestellatner offset etch liquid (manufactured by Gestellatner). Etch liquid for electrophotographic master)
When POP advertisements were printed using this, printing durability was also good.

Comparative example 1 A marker having the following composition was prepared.

〔marker〕

JSR-069230 parts Methanol 10 parts Pilot ink (black) 1 part When this was used to draw a POP advertisement on a Mitsubishi Straight Master using a paintbrush in the same manner as in Example 1, the brushability, drying properties and printing durability were extremely good. However, after drying, a considerable amount of stickiness remained, causing blocking when stacking the masters.

Note that when printing was performed under the printing conditions of Example 1, the printing durability was good.

Example 2 A marker having the following composition was prepared.

〔marker〕

Movinyl 982 30 parts (synthetic resin emulzidine manufactured by Hoechst Synthesis, solid content 48%, MFT
0°C or lower, polyacrylic acid ester polymer) Snowtex 8 10 parts (colloidal silica manufactured by Nissan Chemical Industries ■, solid content 30%) Ethanol 5 parts Pilot ink (black) 1 part This was applied with a paintbrush in the same manner as in Example 1. When I drew POP advertisement content on Nirefax ML-6 (electronic photo master made by Iwatsu), the brush writing, drying, and washability of the brush were extremely good, and there was no stickiness after drying, making the master easy to use. Blocking did not occur when stacked.

Furthermore, when printing was performed under the printing conditions of Example 1, the printing durability was also extremely good.

Comparative example 2 A marker having the following composition was prepared.

〔marker〕

JSR-069330 parts (synthetic latex manufactured by Japan Synthetic Rubber ■, solid content 48%, MF 734°C, styrene-butadiene copolymer) Snowtex C 10 parts Ethanol 10 parts Pilot ink (a) 1 part This was added in the same manner as in Example 1. When POP advertisement content was drawn on a Mitsubishi Straight Master with a paintbrush, the brush writing, drying, and washing properties of the brush were good, and there was no stickiness after drying and no blocking occurred when the masters were stacked.

However, since MFT is high and film formation does not occur at room temperature,
The printing conditions of Example 1 did not provide sufficient printing durability and were not suitable for this purpose.

(F) Effects of the Invention As is clear from the examples, by using the water-based marker for brush drawing of the present invention in plate making for printing POP advertisements,
We were able to establish a plate-making method that combines a high degree of workability with brush strokes and suitability for printing.

This will lead to an increase in the efficiency of the printing work for POP advertisements, which will be increasing in number in the future, so it can be said that the effects of the present invention are extremely large.

Claims (1)

[Claims] 1. When an image such as a character is made by brush painting on an offset printing original plate having an image-receiving layer on a water-resistant support,
A plate-making method characterized by using a water-based paint whose main components are an emulsion-polymerized organic polymer emulsion, an adhesion improver, and a brushability improver. 2. The emulsion polymerized organic polymer emulsion is 25
The plate-making method according to claim 1, characterized in that the film can be formed at temperatures below .degree. 3. The plate-making method according to claim 1, wherein the tackiness improver is colloidal silica. 4. The plate-making method according to claim 1, wherein the amount of the tackiness improver is 10 to 200% based on the solid content of the organic polymer emulsion. 5. The brushability improving agent is methanol, ethanol,
The plate-making method according to claim 1, wherein the lower alcohol is one or more of n-propanol and iso-propanol.