JPS6256967A - Photosensitive resin letterpress material for letterpress printing - Google Patents

Abstract

PURPOSE:To bring a photosensitive resin latterpress material for letterpress printing which permits easy cutting and handling and is extra-thin into practicability without the need for providing a bending set by using an iron sheet having prescribed values of tensile strength, elongation and thickness as a base. CONSTITUTION:The iron sheet having >=55kg/cm<2> tensile strength, <=10% elongation and 0.03-0.12mm thickness is used as the base. The thickness of a photosensitive layer for forming a relief is made >=0.20mm and the entire thickness is made <=0.42mm. The handling including photoengraving is made extremely easy and particularly the easy attachment to and detachment from a plate cylinder of a rotary press are easily executed. The need for preliminarily applying the bending set to the above-mentioned material is eliminated by the light gage of the base itself and the plate is easily cut by scissors, etc.

Description

[Detailed description of the invention] <Industrial application field><Priorart> Conventional letterpress printing used lead plates, zinc plates, copper plates, etc. Since the material was made into a plate, it took time to make it.

Because plate making per square meter is expensive and requires unreliable technology, letterpress printing is moving toward the use of photosensitive resin letterpress materials. However, the conventional iron-based photosensitive resin letterpress material is thick and has to be made in advance before being installed on the plate cylinder.
Carping machines have space in the plate cylinder, which is one of the reasons for the rise in fixed costs.

Since the size of the plate material varies depending on the printing machine model, a cutter is still required to cut the plate material.

Because of these complexities, about 70% of business form printing is done by applying double-sided tape to the entire plate cylinder in advance, pasting a photosensitive resin letterpress plate on a film substrate in a specified position, and then attaching the plate cylinder to the printing machine. However, in order to reduce the downtime of the printing press, at least two cylinders are required for each diameter of the plate cylinder, which increases the fixed costs of purchasing and space, and makes it difficult to remove and install the plate cylinders. The major problem is that it is hard work, and it is difficult and time-consuming to attach the plate to the plate cylinder in a specified position.

<Problems to be Solved by the Invention> The present invention was devised in view of the drawbacks of the prior art, and its purpose is to eliminate the need for creating bends using a carping machine, and to cut with scissors or an NT cutter. 2.The heavy plate cylinders are to be provided every time all plates are replaced.

<Means for solving the problems> The object of the present invention is to achieve a tensile strength of 55 kg/m [112
that's all.

An iron plate with an elongation rate of 10% or less and a thickness of 0.03 to 0.12 mm is used as a support, and the thickness of the photosensitive layer forming the relief is 0.2 mm.
This is achieved by using a photosensitive resin letterpress material for letterpress printing which has a 0- or more.

Currently, in the photosensitive resin letterpress material for letterpress printing that is in practical use, an iron plate with a tensile strength of 30 to 50 kg/- and an elongation rate of 10 or more is used as a support. In order to ensure the functionality, the thickness must be 0.15 mm or more, and the plate thickness of the letterpress material is 0.45 mm or more, which is the addition of 0.30 mm for the photosensitive resin layer.

On the other hand, when using an iron plate with a tensile strength of 55 kg/rym2 or more and an elongation rate of 10% or less according to the present invention, it is possible to reduce the thickness of the support to 12 mm or less. The photosensitive resin layer is 0.20 m thick by
A photosensitive resin letterpress material for letterpress printing with a total thickness of 0.42 [11] and a total thickness of 0.42 [11] can now be put to practical use.

In the present invention, the tensile strength of the iron plate that is the support is 55k.
When the elongation rate is less than g/nnn and exceeds 10%, it is easily deformed and is less practical. In addition, even if the tensile strength is 55 kg/mm or more and the elongation rate is 10% or less, if the thickness exceeds 0.12, the rigidity will be too strong and there will be problems in attaching the plate to the first plate cylinder. Aashi.

Moreover, if the thickness is less than 0.03 mm, the function as a support is poor, and the object of the present invention cannot be achieved in either case.

However, according to the present invention, it is of great significance in that it is possible to provide a photosensitive resin letterpress material for ultra-thin letterpress printing, which was previously impossible, and to put it into practical use. In particular, the material simplifies the plate mounting method for letterpress rotary presses that print on rolls of paper, such as those used in business form printing machines, and allows for quick alignment.

This enables a printing method that eliminates the work of removing and installing the plate cylinder. Needless to say, printing on a normal sheet-fed letterpress printing machine can be done using the conventional method, and the method for attaching the 1st plate is the magnet method, the clamping method with a vise, the clamping part of the 9th plate, and the clamping method. It is also possible to make a hole in the buttocks and attach it to the hole as usual.

The photosensitive resin layer used in the present invention includes various base polymers mixed with a photopolymerization component, a photosensitizer, a heat stabilizer, a plasticizer, and the like. Base polymers include saponified polyvinyl acetate modified with ethylene oxide, and water-soluble polyamide.

Examples include solvent-soluble polyester resins.

Any photopolymerizable component can be blended as long as it has ethylenically unsaturated bonds in its nine molecules and can be compatible with or uniformly mixed with the base polymer. Photosensitizers include benzophenone and benzyl.

All conventionally known sensitizers such as benzyl alkyl ketals can be used. Other conventionally known additives such as heat stabilizers, plasticizers, surfactants, ultraviolet absorbers, dyes, and pigments can be contained.

The thickness of the photosensitive resin layer is preferably 0.2- or more.

If it is less than 0.2, the difference in height between the convex portions (image areas) and the concave areas (non-image areas) of the printing plate is small, so ink also adheres to the concave areas, resulting in so-called bottoming.

This is not preferable because it causes printing defects. The upper limit of the thickness is determined by considering the relationship with the hardness of the photosensitive resin, etc. For example, if the shore D hardness is 65° or more.

1 due to exposure shrinkage and hardening when exceeding 0.55 mIIli.
It is undesirable because it curls toward the plate side and reduces the ease of mounting the 9th plate.

When the shore D hardness is still 40°, if the thickness exceeds 0.80 mm, plate mounting properties deteriorate. In addition, for shore D hardness 20'', it is 1
．． Even with a thickness of 2 mm, no deterioration in plate mounting properties was observed.

Therefore, the thickness of the photosensitive resin layer is 0.20 mm or more, preferably 0.31 m1 or more, and more preferably 0°3
The upper limit of 5 mm or more is appropriately selected depending on the application.

As the support in the present invention, it is preferable to use a thin rolled steel plate that is not made of iron and has high strength and magnetic properties, and also satisfies the required properties as a printing material such as smoothness and thickness accuracy. This can be purchased as an unannealed ultra-thin rolled steel sheet, generally known as zinc pot first (or nine first), which is zinc-plated (or tin-plated) to an intermediate thickness and then rolled to a standard thickness.

Commonly available materials include, for example, "Steel Foil" manufactured by Toyo Kobe ■, "Steel Paper" manufactured by Igeta Steel Sheet, and "Steel Foil" manufactured by Nippon Steel ■.

The surface of the support is preferably plated or chemically treated for rust prevention, but is not particularly limited. Further, the adhesion treatment on the surface of the support can be performed by a conventionally known method. .

For strong adhesion with the photosensitive resin layer, adhesives with an appropriately determined composition can be obtained by using epoxy, phenol resin, incyanate, polyester, polyurethane, polyvinyl acetate, chloroprene rubber, etc. alone or in combination. This is done through layers.

It is also possible to mount a suitable cover film on the surface of the photosensitive resin layer for protection. An example of such a film is polyester film.

Polypropylene film, polyethylene film.

Although 9 and polyvinylidene chloride films can be used, polyester films are preferred from the viewpoint of dimensional stability and oxygen barrier properties, and polyethylene terephthalate films are most suitable. Furthermore, if the surfaces of these films are matted, the matte shape will be transferred to the plate surface, making it easier to vacuum-adhere the negative film during plate making.

Of course, it is also possible to use the device without attaching these cover films.

<Function> The photosensitive resin plate material of the present invention thus obtained can be easily made into a photosensitive resin letterpress plate for letterpress printing by plate making through ordinary exposure and development steps.

A more specific explanation will be given below using Examples and Comparative Examples.

Example 1. Comparative Example 1 Chrome-plated steel plate (A) with a tensile strength of 43 kg/mm, an elongation rate of 28.0%, and a thickness of 0.20 tIIllo, a tensile strength of 50 coffins/mm, an elongation rate of 15.3%, and a thickness of 0.0
5mm rolled steel plate (B), tensile strength 72 kg/mm
, a zinc fast steel plate (C) with an elongation factor of 1.6 and a thickness of 0.05 mm, and a tensile strength of 65/=2. Elongation rate 1.
Zinc first steel plate (D) with 7% and thickness of 0.10mm
A polyester/insyanate adhesive was applied to each of the adhesives so that the dry film thickness was 0°02-.

These were placed in a hot air oven at 150°C for 5 minutes to remove the solvent, and four types of adhesive-treated supports (A, D) were prepared.

Next, partially saponified polyvinyl acetate with a degree of saponification of 75 molty 9 and a degree of polymerization of about 600 was used as a base polymer, and after dissolving it in a mixed solvent of ethanol/water = 50,750 (weight ratio), propylene glycol diglycidyl ether diacrylate was dissolved. A photopolymerizable monomer, benzyl dimethyl ketal as a photosensitizer, and diethylene glycol/l/ as a plasticizer were added and mixed to prepare a photosensitive resin composition solution.

This solution was cast onto each of the adhesive-treated supports so that the dry thickness would be as shown in Table 1, and the solution was placed in an open oven at 50°C for 2 hours to remove the solvent and correspond to A-D. A photosensitive resin plate material was obtained. A general negative film for cash receipts is vacuum-adhered onto these plates, exposed for 2 minutes using an ultra-high pressure mercury lamp, and then developed using a brush developing machine filled with neutral water until the unexposed areas are completely eluted. I did it. After this, 50
It was thoroughly dried for 10 minutes in the open air at ℃.

The seven types of photosensitive resin letterpress plates for letterpress printing made in this way were bent with a plate bending machine with a plate bending angle of 20''. Full thickness, 45 mm can be installed, and it has a groove for temporary insertion, the groove cutting angle is 30 degrees, the groove width is 0.8, the groove depth is 10, and the plate cylinder with a plate winding rod is installed at the back of the groove. Table 1 shows the results of printing after attaching a plate to a newly manufactured and installed plate.

From the results in Table 1, the support applicable to the present invention (symbol C1D,
E, F, G)'i The printing plate I used had good flatness.

It was confirmed that it was easy to attach and detach from the plate cylinder, and that there were no problems with the finish of printed matter. -If the resin layer thickness is 0.2mm, you need to be careful in adjusting the pressure between the roller and the plate, if the resin layer is 0.25mm, you need to be careful, and if the resin layer is 0.6mm, you don't have to be so careful when printing. was possible.

<Effects of the Invention> Since the photosensitive resin letterpress plate for letterpress printing according to the present invention is configured as described above, it can have a total thickness of 0.42- or less and is easy to handle including plate making.

In particular, it can be easily attached to and detached from the plate cylinder of a rotary press. In addition, the support itself can be made thin, and it can be easily cut with scissors, without the need for pre-curving unlike conventional iron plate substrates. It has excellent effects such as being able to handle it like a conventional iron plate.

Claims (1)

[Claims] Tensile strength 55kg/mm^2 or more, elongation rate 10% or less,
A photosensitive resin letterpress material for letterpress printing, which uses an iron plate with a thickness of 0.03 to 0.12 mm as a support and has a photosensitive layer forming a relief with a thickness of 0.20 mm or more.