JP2017061092A - Gravure printing cylinder, and resin composition for gravure version formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure printing cylinder including a comparatively-inexpensive resin layer reusable by being peeled off after use.SOLUTION: A gravure printing cylinder includes a cylinder, and a resin layer formed of polyamide imide on the outside surface of the cylinder. As another form, it is also preferable that the gravure printing cylinder include the cylinder, and a curable resin layer formed from a composition containing polyamide imide and a bisphenol type epoxy resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gravure cylinder provided with a resin layer, and a resin composition used for forming the resin layer.

  Gravure printing cylinders used for gravure printing are generally electroplated with a copper layer on the surface of a cylinder made of a hollow iron core member, and in the next step, an image forming part consisting of recesses is formed by a diamond stylus or laser etching machine. It is produced by engraving a copper layer digitally. However, since the copper layer is soft and has low durability, a thin chrome plating layer formed by electroplating on the copper layer is formed on the outermost surface as the next step for the cylinder engraved with the recess. The The gravure printing cylinder that has undergone such a process can have durability against long-time gravure printing. Since a gravure cylinder goes through a number of processes, it requires cost and time to manufacture. There are also environmental problems such as the expense and time required for the treatment of harmful substances such as chromium compounds used in the plating process.

  Thus, as an alternative material for the chrome plating layer, Patent Literature 1 and Patent Literature 2 disclose a gravure printing cylinder using a diamond-like carbon coating.

JP2007-118594A JP2007-130996A

  However, the formation of the diamond-like carbon film has a high cost problem. Further, the gravure printing cylinder is generally reused. However, the diamond-like carbon film has a problem that it is difficult to peel off due to its high hardness and difficult to reuse.

  An object of the present invention is to provide a gravure printing cylinder having a resin layer that is relatively low cost and can be peeled off and reused after use.

  The cylinder for gravure printing of the present invention includes a cylinder and a resin layer formed from polyamideimide on the outer surface of the cylinder.

  According to the present invention having the above-described configuration, the resin layer contains polyamideimide, so that both the hardness to withstand gravure printing and the reuse of the gravure printing cylinder can be achieved.

  According to the present invention, it is possible to provide a gravure printing cylinder having a resin layer that can be peeled off after use and reused.

FIG. 1 is a perspective view of a gravure cylinder. FIG. 2 is a side view of the gravure cylinder. FIG. 3 is a schematic cross-sectional view of a simple engraving test.

The cylinder for gravure printing of the present invention includes the cylinder of the first aspect and a resin layer formed from polyamideimide on the outer surface of the cylinder. A gravure plate is formed by engraving the surface of the resin layer of the gravure cylinder.
The cylinder for gravure printing of the present invention has a hardness that can withstand continuous printing even though it is a resin layer, and is excellent in economy because it can be reused by peeling off the resin layer after use.

According to FIG. 1, the cylinder for gravure printing is made of metal and has a hollow structure inside although not shown. The cylinder 1 has hollow holes 2 on both side surfaces thereof, and is attached to the gravure printing machine through the hollow holes 2.
Examples of the material of the cylinder 1 include iron and aluminum. Among these, iron is preferable in terms of durability. The size of the cylinder 1 can be appropriately adjusted according to the specifications of the printing press, and the outer periphery is usually about 300 to 1500 mm. Moreover, the width | variety of the cylinder 1 is about 150-2000 mm normally.
The diameter of the hollow hole 2 can be appropriately adjusted according to the specifications of the gravure printing machine, but is usually about 60 to 130 mm.
The resin layer 3 is formed on the outer surface of the cylinder 1. Since the resin layer forms a gravure plate instead of the conventional copper layer, the thickness thereof is about 5 to 300 μm.

Next, it is also preferable to use the cylinder of the second embodiment for the gravure printing cylinder of the present invention. The cylinder of the second aspect includes a copper layer on the outer surface of the cylinder 1 although not shown. A resin layer 3 is formed on the surface of the copper layer.
When using the cylinder of the second embodiment, the surface of the copper layer is engraved to form a gravure plate. The resin layer 3 covers the surface of the gravure plate and prevents its wear.
In this case, since the resin layer 3 functions as a protective layer for the copper layer, the thickness thereof is about 1 to 10 μm.

In the present invention, the first aspect of the resin layer is a non-crosslinked (non-cured) layer formed using polyamideimide. The first embodiment of the resin layer can be applied to the “cylinder of the first embodiment” and the “cylinder of the second embodiment”.
Polyamideimide is difficult to dissolve in a solvent, but can be dissolved in a limited organic solvent such as N-methyl-2-pyrrolidone (NMP) or γ-butyrolactone (GBL), so that a resin solution can be formed.

  A resin layer is formed by painting on the surface of the cylinder using this resin solution. At the time of forming this resin layer, a drying step for volatilizing the organic solvent is included. However, the first embodiment of the resin layer does not require crosslinking (curing) of polyamideimide. Due to the hardness and cohesive strength of polyamideimide without crosslinking of the resin layer, the hardness capable of continuous printing and the reuse by peeling the resin layer become possible.

Polyamideimide is generally synthesized by the following two methods. (1) Isocyanate method: a known method in which trimellitic anhydride and diisocyanate are reacted. (2) Acid chloride method: A known method in which trimellitic anhydride chloride and diamine are reacted.
As the polyamideimide, for example, a commercially available product, Viromax (registered trademark) series (manufactured by Toyobo Co., Ltd.) can be used.

  The number average molecular weight (Mn) of the polyamideimide is preferably 15000 to 30000. By satisfying the above range, the hardness and cohesive force of the resin layer are improved.

The required thickness in consideration of engraving as the gravure plate of the resin layer is preferably about 50 to 300 μm. This thickness may be formed by a single coating, or may be formed by a plurality of coatings (also referred to as “multiple coating”).
When overcoating, repeat the pre-drying process before the main drying to increase the film thickness, and if the final drying process is performed once at the end, the hardness of the coating is between the surface part and the deep part. Is preferable because the difference is small.

The resin layer can be formed on the surface of the cylinder using a known coating device.
Examples of the coating apparatus include spin coating, dip coating, slot coating, roll coating, spray coating, electrostatic spray coating, and ring coating. Of these, electrostatic spray coating and ring coating are preferred. When the resin layer is formed on the “cylinder of the second embodiment”, the electrostatic spray coating method is preferable. After coating, the resin layer is obtained by drying with a known apparatus such as a hot air oven or an infrared heater to remove the organic solvent. The drying conditions are preferably about 120 to 200 ° C. and about 5 to 60 minutes, for example. In addition, since the said drying conditions are performed in order to volatilize an organic solvent, you may change temperature and time suitably.

  Although not shown, the resin layer can be formed on a base layer (also referred to as an anchor layer) previously formed on the outer surface of the cylinder.

In the present invention, the second aspect of the resin layer is a cured resin layer (hereinafter also referred to as a cured resin layer). The cured resin layer is formed using a gravure plate-forming resin composition (hereinafter referred to as a resin composition) containing polyamideimide and a bisphenol-type epoxy resin. The difference between the first embodiment and the second embodiment is the same except that the resin composition is used. In the second aspect, a harder resin layer can be formed by crosslinking (curing) the polyamideimide and the bisphenol-type epoxy resin after application of the resin composition. The first embodiment of the resin layer can be applied to the “cylinder of the first embodiment” and the “cylinder of the second embodiment”. The conditions for drying and curing when forming the cured resin layer are as follows. Pre-drying is performed by heating at about ~ 200 ° C for about 5 to 60 minutes. Subsequently, it hardens by heating at 180-250 degreeC for 30-120 minutes. The coating may be performed once or a plurality of times as in the first embodiment. It is preferable that the coating is performed a plurality of times and the preliminary drying is performed for each coating, and the heat curing is performed once after the coating is completed. Thereby, the variation in the hardness of the surface and the deep part of the cured resin layer can be minimized. The predrying condition is more preferably about 120 to 150 ° C. and about 5 to 30 minutes.

In the present invention, the bisphenol type epoxy resin is a resin having an epoxy group as a crosslinkable functional group synthesized by a known reaction using a bisphenol compound as a starting material.
Examples of the bisphenol compound include bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol Z and the like. Is mentioned. Among these, bisphenol A and bisphenol F are preferable, and bisphenol A is more preferable.
That is, the bisphenol type epoxy resin is preferably a bisphenol A type epoxy resin or a bisphenol F type epoxy resin.

  It is preferable that 5-100 mass parts is mix | blended with respect to 100 mass parts of polyamideimides, and 10-50 masses is more preferable for a bisphenol type epoxy resin. When an appropriate amount of bisphenol type epoxy resin is blended, the hardness of the cured resin layer is further improved.

The resin composition can further contain an inorganic filler. The hardness of the cured resin layer is further improved by including the inorganic filler. In addition, you may mix | blend an inorganic filler with the resin solution used for formation of the 1st aspect of a resin layer.
10-100 nm is preferable and, as for the average particle diameter of an inorganic filler, 10-50 nm is more preferable. By setting the average particle size within an appropriate range, the hardness of the cured resin layer is further improved, and the solution stability of the composition is improved. In addition, an average particle diameter is the numerical value measured according to the specific surface area measured value (JISZ8830) by a BET adsorption method.
Examples of the inorganic filler include titanium oxide, iron oxide, zinc oxide, zirconium oxide, magnesium oxide, silica, alumina, kaolin, and silicon nitride. Of these, silica and alumina are preferable.
As the inorganic filler, for example, the Snowtex (registered trademark) series, the organosilica sol series, and the light star (registered trademark) series of Nissan Chemical Co., Ltd. can be used.

  For blending the inorganic filler, a method of blending a solution dispersed with a solvent using a disperser such as a bead mill with other raw materials or a method of dispersing the inorganic filler with other raw materials using a disperser is preferable.

  It is preferable that an inorganic filler contains 0.1 mass part or more and less than 10 mass parts with respect to 100 parts of polyamideimides. By using an inorganic filler in an appropriate range, the solution stability of the resin composition is improved, the resin composition is easily coated on the cylinder, and the hardness of the cured resin layer is further improved.

  The resin layer of the first embodiment and the resin layer of the second embodiment can further contain additives. Examples of the additive include a coating surface conditioner such as DISPERBYK (registered trademark) series of Big Chemie Japan.

  The gravure printing cylinder of the present invention can form a gravure plate by engraving the surface of a resin layer (including a cured resin layer) into a desired shape. This gravure plate preferably satisfies the solvent resistance because continuous printing is performed using a printing ink containing an organic solvent (for example, methyl ethyl ketone). The resin layer preferably has a hardness that can withstand continuous printing (for example, a pencil hardness of about 5H).

  The gravure plate is formed by engraving the surface of the resin layer (in the case of the cylinder of the second aspect, the copper layer surface) with an engraving needle (diamond slitas) equipped with a diamond at the tip. A method of making a cell to be filled is common. Engraving is generally performed by a digital method using a computer.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. “Part” is “part by mass”, and “%” represents “% by mass”.

Example 1
Polyamideimide (manufactured by Toyobo Co., Ltd., Mn; 30000) and N-methyl-2-pyrrolidone (NMP) were stirred and mixed to obtain a resin composition having a nonvolatile content of 10%.

  A sample having a resin layer thickness of 100 μm is obtained by coating the obtained resin composition on a steel plate (manufactured by JFE Steel) with a thickness of 0.25 mm using an applicator and then drying by heating at 150 ° C. for 30 minutes. I got a plate.

(Example 2)
Mixing 100 parts of polyamideimide (Toyobo Co., Ltd., Mn; 30000) and 5 parts of bisphenol A type epoxy resin (JER1001 manufactured by Mitsubishi Chemical Corporation), stirring and mixing with N-methyl-2-pyrrolidone (NMP) A 10% resin composition was obtained.
The obtained coating liquid was applied onto a steel plate (manufactured by JFE Steel) having a thickness of 0.25 mm using an applicator, and pre-dried at 150 ° C. for 30 minutes. Subsequently, the sample board whose thickness of a resin layer is 100 micrometers was obtained by heat-curing for 30 minutes at 200 degreeC.

(Example 3)
A sample plate was obtained in the same manner as in Example 2 except that 10 parts of bisphenol A type epoxy resin was blended with 100 parts of polyamideimide of Example 2.

Example 4
A sample plate was obtained in the same manner as in Example 2 except that 20 parts of bisphenol A type epoxy resin was blended with 100 parts of polyamideimide of Example 2.

(Example 5)
A sample plate was obtained in the same manner as in Example 4 except that the bisphenol A type epoxy resin of Example 4 was changed to a bisphenol F type epoxy resin (JER4004P manufactured by Mitsubishi Chemical Corporation).

(Example 6)
A sample plate was obtained in the same manner as in Example 2 except that 30 parts of bisphenol A type epoxy resin was blended with 100 parts of polyamideimide in Example 2.

(Example 7)
A sample plate was obtained in the same manner as in Example 2 except that 50 parts of bisphenol A type epoxy resin was blended with 100 parts of polyamideimide in Example 2.

(Comparative Example 1)
Polyester (manufactured by Toyobo Co., Ltd., Mn; 20000) was stirred and mixed with N-methyl-2-pyrrolidone (NMP) to obtain a resin composition having a nonvolatile content of 10%.
A sample plate was obtained by carrying out the obtained resin composition in the same manner as in Example 2.

  The following items were evaluated for the sample plates obtained in Examples 1 to 7 and Comparative Example 1.

<Pencil hardness test>
For the obtained sample plate, no. Using a 533 pencil scratch hardness tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the pencil scratching method specified in JIS K 5600-5-4 is performed, and the resin layer is broken so that the steel plate surface is not exposed. Hardness.

<Solvent resistance test>
For the sample plate produced after measuring the mass of the steel plate in advance, the mass of the resin layer is calculated by subtracting the mass of the steel plate. Next, the sample plate is immersed in organic solvent methyl ethyl ketone (MEK) at 25 ° C. for 24 hours. Thereafter, the surface of the sample plate is washed with MEK, heated at 100 ° C. for 30 minutes and dried to remove MEK. The mass of the dried sample plate was measured, and the mass of the resin layer after immersion was calculated. The obtained numerical value was substituted into the following formula to calculate the MEK insoluble matter.
MEK insoluble content = (mass of resin layer after immersion / mass of resin layer before immersion) × 100

<Engraving test>
The surface of the resin layer 6 of the sample plate obtained for simple evaluation of the engraving performance of the gravure plate described with reference to FIG. 3 is simplified using a diamond slitus 4 of a table-top engraving machine magic2 (manufactured by Sea Force). Automatic engraving was performed to form a conical cell 8 having a diameter of 1 mm. Next, the surface of the resin layer in the vicinity of the cell 8 was observed with an optical microscope and evaluated according to the following criteria.
○: There was no abnormality in the resin layer. Are better.
Δ: Slight cracking occurred in the resin layer. Practical area.
X: Many cracks occurred in the resin layer. Not practical.

<Solution stability>
The resin compositions obtained in each Example and Comparative Example were sealed with a glass bottle and allowed to stand at 25 ° C. for 24 hours. Next, the solution state of the resin composition was visually observed and evaluated according to the following criteria.
A: Good solution state.
○: Although there was no change in the solution appearance, the viscosity increased slightly when the glass bottle was tilted. Practical area x: The solution was separated or settled. Impractical

<Paintability>
The surface state of the resin layer of the obtained sample plate was visually observed and evaluated according to the following criteria.
A: A good resin layer having smooth gloss was obtained.
○: A smooth but slightly glossy resin layer was obtained. Practical range x: A resin layer with streaks on the surface and low gloss was obtained. Impractical

  Next, the example which mix | blended the inorganic filler further is shown.

(Example 10)
Polyamideimide (Toyobo Co., Ltd., Mn; 30000) 100 parts, silica dispersion with an average particle size of 15 nm (non-volatile content 40%, Nissan Chemical Industries, Ltd.) as an inorganic filler is blended in 5 parts in terms of non-volatile content, and N-methyl- 2-Pyrrolidone (NMP) was added and mixed by stirring to obtain a resin composition having a nonvolatile content of 10%.
The obtained resin composition was applied onto a steel plate (manufactured by JFE Steel) having a thickness of 0.25 mm using an applicator and pre-dried at 150 ° C. for 30 minutes. Subsequently, the sample board whose thickness of a resin layer is 100 micrometers was obtained by heat-curing for 30 minutes at 200 degreeC.

(Example 11)
100 parts of polyamide-imide (manufactured by Toyobo Co., Ltd., Mn; 30000) and 50 parts of bisphenol A type epoxy resin (JER1001 manufactured by Mitsubishi Chemical Corporation) are blended, and a silica dispersion solution having an average particle size of 15 nm as an inorganic filler (Nissan Chemical Industry Co., Ltd.) 5 parts of resin and filler were converted in terms of non-volatile content. Next, dilution adjustment was performed using N-methyl-2-pyrrolidone (NMP) so that the non-volatile content was 10% to obtain a resin composition. Except that, a sample plate was obtained in the same manner as in Example 10.

(Example 12)
A sample plate was obtained in the same manner as in Example 10 except that the inorganic filler in Example 11 was blended with a silica dispersion having a particle size of 50 nm (manufactured by Nissan Chemical Industries, Ltd.).

(Example 13)
A sample plate was obtained in the same manner as in Example 10 except that the inorganic filler in Example 11 was blended with a silica dispersion having a particle size of 100 nm (manufactured by Nissan Chemical Industries, Ltd.).

  The sample plates obtained in Examples 10 to 13 were evaluated in the same manner as described above.

From the result of Table 1, Examples 1-7 have the hardness which can be continuously printed as a gravure because the pencil hardness of the resin layer is 5H or more. In the solvent resistance test, the solvent insoluble fraction is 97% or more, so that it has a solvent resistance that can withstand the organic solvent in the gravure ink. It has solvent resistance that can withstand use as a gravure plate, such as not losing the glossiness of the coating film even after immersion in a solvent. Moreover, it turns out that the resin layer which can be practically used is obtained from the simple engraving test.
On the other hand, from the results in Table 2, in Comparative Example 1, the pencil hardness of the resin layer is low and the hardness is insufficient for use as a gravure plate. Further, Comparative Example 1 has low resistance to methyl ethyl ketone (MEK), and is not suitable for use in ink containing a large amount of solvent such as MEK. Further, Comparative Example 2 cannot be used as a gravure plate because the resin layer is brittle and many cracks are generated in the resin layer in a simple engraving test.
Moreover, since the hardness of the resin layer has improved the Examples 10-12 from the result of Table 3 by mix | blending an inorganic filler, the gravure plate in which continuous printing is possible can be formed.

1 Cylinder 2 Hollow Hole 3 Resin Layer 4 Diamond Slytas 5 Diamond 6 Resin Layer 7 Steel Plate 8 Cell

Claims (5)

  A cylinder for gravure printing, comprising a cylinder and a resin layer formed of polyamideimide on the outer surface of the cylinder.   A cylinder for gravure printing, comprising a cylinder and a cured resin layer formed on the outer surface of the cylinder from a composition containing polyamideimide and a bisphenol type epoxy resin.   A gravure plate-forming resin composition comprising a polyamideimide and a bisphenol-type epoxy resin.   The resin composition for forming a gravure plate according to claim 3, comprising 5 to 100 parts by mass of the bisphenol type epoxy resin with respect to 100 parts by mass of the polyamideimide. Furthermore, the resin composition for gravure plate formation of Claim 3 or 4 which contains an inorganic filler 0.1 mass part or more and less than 10 mass parts with respect to 100 mass parts of said polyamideimide.

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