KR20210027694A - A method of manufacturing gravure roll and a gravure roll manufactured by the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a gravure roll used for gravure printing, and a gravure roll manufactured thereby. According to the present invention, the method comprises a metal deposition layer forming step of forming a metal deposition layer formed by a sputtering method on a surface of a copper plated layer.

Description

A method of manufacturing a gravure roll and a gravure roll manufactured by the method {A method of manufacturing gravure roll and a gravure roll manufactured by the same}

The present invention relates to a method of manufacturing a gravure roll used for gravure printing and a gravure roll manufactured thereby, and more particularly, to a metal deposition layer formed by a sputtering method on the surface of a copper plating layer on which a printing pattern is formed. It relates to a method for manufacturing a gravure roll having a structure in which the surface is reinforced by forming and a gravure roll manufactured by the method.

Gravure printing refers to a method of forming a pattern on the surface of a cylindrical roll in an intaglio shape, injecting ink into the pattern, and then transferring the pattern onto the surface of a continuous print object wound in a roll shape for printing. Gravure printing is widely used not only in photography, packaging, textiles, but also in electronic materials due to its high speed and high quality.

In the gravure roll used for conventional gravure printing, a copper plating layer for plate surface formation is formed on the cylindrical core surface, a printing pattern is formed on the copper plating layer, and a chromium plating layer is formed thereon to have abrasion resistance.

However, in the case of the chromium plating layer to protect the copper plating layer, since a plating bath containing hexavalent chromium is used, it is dangerous because it can cause skin disease or respiratory disease to the worker, and it generates gas and wastewater. It has become a factor that pollutes the natural environment. The hexavalent chromium compound is mainly composed of chromate and dichromate, which are chemically active, highly toxic, and very harmful to the human body. The use of hexavalent chromium is strictly regulated in major developed countries such as Europe, the United States, and Japan.

In addition, conventional gravure rolls have improved surface hardness and abrasion resistance by patterning the surface of the copper plating layer and then applying the chromium plating layer to a thickness of about 5 to 7 μm. It causes (micro crack). These microcracks cause a chipping phenomenon on the surface of the chromium plating layer, and thus there is a problem that acts as a factor of printing defects.

Korean Patent Registration Publication No. 10-1520415 Korean Patent Publication No. 10-2019-0064102

The present invention is to solve the above-described problem, and an object of the present invention is to provide a method capable of manufacturing a gravure roll without a chromium plating process using hexavalent chromium, and a gravure roll manufactured by the method. .

In addition, an object of the present invention is to provide a method of manufacturing a gravure roll capable of preventing microcracks occurring in the chromium plating layer forming the surface of the gravure roll and the resulting chipping phenomenon, and a gravure roll manufactured by the method.

In addition, an object of the present invention is to provide a method of manufacturing a gravure roll capable of high safety in a workplace and preventing environmental pollution, and a gravure roll manufactured by the method.

The method of manufacturing a gravure roll according to the present invention for achieving the above object includes a copper plating layer forming step of forming a copper plating layer having a thickness of 50 to 200 μm (micrometer) on the surface of a cylindrical metal core, and on the surface of the copper plating layer. A photoresist coating step of applying a photoresist, an exposure and development step of forming a predetermined pattern on the photoresist by removing a part of the photoresist so as to have a pattern corresponding to a print pattern to be formed on the copper plating layer; , An etching step of forming a predetermined print pattern by etching the copper plating layer using the photoresist with the pattern formed in the exposure and development steps as a mask, and removing the photoresist remaining on the surface of the copper plating layer on which the print pattern is formed. And a peeling step of forming a surface reinforcing layer for enhancing hardness and abrasion resistance of the surface of the copper plating layer in a state in which the photoresist is removed, and the step of forming the surface reinforcing layer comprises forming a surface of the copper plating layer. A plasma surface treatment step of etching with plasma, and a metal deposition layer forming step of forming a metal deposition layer having a thickness of 3 to 7 µm (micrometer) by a sputtering process on the surface of the copper plating layer treated in the plasma surface treatment step. .

In addition, the metal deposition layer formed in the metal deposition layer forming step may be any one of chromium (Cr), chromium nitride (CrN), chromium carbide (CrC), and tungsten carbide (WC).

In addition, when the metal deposition layer is chromium (Cr), the metal deposition layer forming step is a sputtering process using a chromium target, and may be performed by injecting argon (Ar) gas into the chamber at a predetermined flow rate and applying a bias voltage. .

In addition, when the metal deposition layer is chromium nitride (CrN), the metal deposition layer forming step is a sputtering process using a chromium target, in which argon (Ar) gas and nitrogen (N ₂ ) gas are added to the chamber 2: 1 to 9: It can be performed by applying a bias voltage while injecting a predetermined flow rate at a mixing ratio of 1.

In addition, when the metal deposition layer is chromium carbide (CrC), the metal deposition layer forming step is a sputtering process using a chromium target, in which argon (Ar) gas and methane (CH ₄ ) gas are added to the chamber 2: 1 to 9: It can be performed by applying a bias voltage while injecting a predetermined flow rate at a mixing ratio of 1.

In addition, when the metal deposition layer is tungsten carbide (WC), the metal deposition layer forming step is a sputtering process using a tungsten target, in which argon (Ar) gas and methane (CH ₄ ) gas are added to the chamber from 2: 1 to 9: It can be performed by applying a bias voltage while injecting a predetermined flow rate at a mixing ratio of 1.

In addition, the step of forming the surface reinforcement layer may further include forming a diamond-like carbon layer on the surface of the metal deposition layer formed in the step of forming the metal deposition layer.

The method of manufacturing a gravure roll according to the present invention provides a method of manufacturing a gravure roll having excellent wear resistance even without a conventional hexavalent chromium plating process. The method for manufacturing a gravure roll according to the present invention provides a method for manufacturing a gravure roll having excellent hardness and abrasion resistance by forming a metal deposition layer by a sputtering process on the surface of a copper plating layer on which a printing pattern is formed. Therefore, it is possible to prevent environmental pollution due to hexavalent chromium, which may occur during the conventional chromium plating process, and increase the safety of the working environment. In addition, the metal deposition layer formed by the sputtering process has a dense composition structure and has excellent hardness and abrasion resistance, so that it can replace the chromium plating of the conventional gravure roll. Therefore, micro-cracks and chipping defects accompanying the chromium plating layer can be eliminated.

1 is a flow chart showing a method of manufacturing a gravure roll according to an embodiment of the present invention.
2 is a view schematically showing a cross-sectional configuration of each layer of a gravure roll manufactured according to a method of manufacturing a gravure roll according to a preferred embodiment of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. Various modifications may be made to the embodiments described below by those of ordinary skill in the art to which the present invention pertains. The embodiments described below are not described to limit the present invention to the corresponding embodiments. It should be understood that the present invention includes various modifications, substitutes, and equivalents within the scope of the technical idea understood from the entire specification as well as the following examples.

It should be understood that expressions such as "include", "consist of" and "have" that may be used hereinafter do not exclude additional elements or functions. Hereinafter, in the use of terms, the singular expression should be understood as not excluding the plural expression unless explicitly stated.

1 is a flowchart showing a method of manufacturing a gravure roll according to a preferred embodiment of the present invention, and FIG. 2 is a cross-sectional view of each layer of a gravure roll manufactured by a method of manufacturing a gravure roll according to a preferred embodiment of the present invention. It is a diagram schematically showing the configuration.

Referring to these, the method of manufacturing a gravure roll according to the present invention includes a core preparation step (S10) (see Fig. 2 (a)). The core 1 has a hollow cylindrical shape. The core 1 may be made of a metal having a predetermined mechanical stiffness and durability, and may be made of, for example, steel or aluminum.

Next, a copper plating layer forming step S20 of forming a copper plating layer for forming a pattern for printing on the prepared surface of the core 1 is performed (see FIG. 2(b)). The copper plating layer 2 formed on the surface of the core 1 is a layer on which an uneven pattern for printing is formed. The printed pattern may be formed by an etching process to be described later. The copper plating layer 2 is a metal that is easily patterned and may be formed on the surface of the core by electroplating. It is preferable that the copper plating layer 2 has a predetermined thickness, and may be, for example, 50 to 200 μm (micrometer). If the thickness is less than 50㎛ (micrometer), sufficient thickness to form a print pattern cannot be secured. If the thickness exceeds 200㎛ (micrometer), the soft copper plating layer (2) becomes too thick and mechanical strength It can be disadvantageous on the side. In addition, the copper plating layer forming step S20 may include a polishing step to remove foreign substances from the surface of the copper plating layer 2 and planarize the surface. In this embodiment, a case where a copper plating layer is used to form a printing pattern is exemplified, but in some cases, a metal layer made of gold, silver, zinc, cadmium, tin, lead, etc. may be formed instead of the copper plating layer. have.

Next, a photoresist coating step (S30) of applying a photoresist on the copper plating layer is performed (see FIG. 2(c)). The photoresist 3 is for functioning as a mask in an etching process to be carried out later. The photoresist 3 may be a positive photoresist or a negative photoresist.

Next, exposure and development steps (S40) for forming a predetermined pattern on the applied photoresist are performed (see FIG. 2(d)). In the exposure and development step 40, the photoresist 3 at a position corresponding to the print pattern to be formed on the copper plating layer 2 is removed. For example, when a positive photoresist is used, light is irradiated onto the photoresist corresponding to the position where the print pattern is to be formed, and the photoresist at the portion irradiated with light is removed. Conversely, when a negative photoresist is used, light is irradiated onto the photoresist corresponding to a position where a print pattern is not formed, and the photoresist in the rest of the photoresist is removed except for the irradiated portion. Part of the photoresist 3p is removed by the exposure and development step S40, leaving the patterned photoresist 3p.

Next, an etching step (S50) for forming a print pattern on the copper plating layer is performed (see Fig. 2(e)). The copper plating layer 2 is etched using the photoresist 3p patterned through the exposure and development step S40 as an etching mask. A printed pattern of a predetermined depth is formed on the copper plating layer 2 to form a patterned copper plating layer 2p.

Next, a stripping step (S60) of removing the photoresist used as an etching mask is performed (see Fig. 2(f)). In the peeling step (S60), all of the photoresist 3p attached to the surface of the copper plating layer 2p on which the printed pattern is formed is removed.

Next, a surface reinforcing layer forming step (S70) for imparting predetermined hardness and abrasion resistance to the surface of the copper plating layer on which the printed pattern is formed is performed. In the surface enhancement layer forming step (S70), a metal deposition layer 4A by a physical vapor deposition (PVD) method is formed on the patterned surface of the copper plating layer 2p.

The metal deposition layer 4A may be formed of any one of chromium (Cr), chromium nitride (CrN), and chromium carbide (CrC). Alternatively, the metal deposition layer 4A may be made of tungsten carbide (WC).

The surface reinforcement layer forming step S70 may include a plasma surface treatment step S71 for improving adhesion to the surface of the copper plating layer 2p on which the printed pattern is formed prior to forming the metal deposition layer 4A. In the plasma surface treatment step S71, plasma treatment according to predetermined conditions is performed on the surface of the copper plating layer 2p on which the printed pattern is formed. For example, in the plasma surface treatment step (S71), ^{while injecting argon (Ar) gas into the plasma chamber under a 5 X 10 -5} Torr vacuum condition, a bias of 1500 V (volt), 0.35 A (ampere), and 500 W (watt). ) Can be performed for 1 to 2 hours.

The metal deposition layer forming step (S72) for forming the metal deposition layer 4A on the plasma surface-treated copper plating layer 2p may be performed by a sputtering process, which is a kind of physical vapor deposition (PVD) method. (See Fig. 2(g)).

When the metal deposition layer 4A is chromium (Cr), the metal deposition layer 4A may be formed by a sputtering process using a high purity (eg, 99.9% to 99.95%) chromium target. The sputtering process is a condition of injecting high purity (eg, 99.999%) argon (Ar) gas into the chamber at a predetermined flow rate (eg, 70 sccm) while applying a predetermined bias (eg, 70 ~ 100V (volt)) voltage to the chamber. Can be done in It is preferable that the thickness of the metal deposition layer 4A is 3 to 7 µm (micrometer).

Even when the metal deposition layer 4A is chromium nitride (CrN), the metal deposition layer 4A may be formed by a sputtering process using a high purity chromium target. In this case, high purity argon (Ar) gas and high purity nitrogen ( N ₂ ) A chromium nitride (CrN) layer can be formed by injecting a gas mixed with a gas at a predetermined flow rate (eg, 70 sccm) and applying a predetermined bias (eg, 70 to 100 V (volt)) voltage. The mixing ratio of argon gas and nitrogen gas is preferably in the range of 2:1 to 9:1. On the other hand, in the starting step of depositing the chromium nitride (CrN) layer, only argon (Ar) gas is injected for a certain period of time (for example, within 10 minutes) and sputtering is performed. ) Layer can be formed to increase the adhesion to the copper plating layer (2p). It is preferable that the thickness of the metal deposition layer 4A is 3 to 7 µm (micrometer).

Even when the metal deposition layer 4A is chromium carbide (CrC), the metal deposition layer 4A may be formed by a sputtering process using a high-purity chromium target. In this case, by injecting a mixture of high-purity argon (Ar) gas and methane (CH ₄ ) gas at a predetermined flow rate (e.g., 70 sccm) and applying a predetermined bias (e.g., 70 ~ 100V (volts)) voltage to the chamber. A chromium carbide (CrC) layer may be formed. The mixing ratio of argon gas and methane gas is preferably in the range of 2:1 to 9:1. At the start of depositing the chromium carbide (CrC) layer, sputtering is performed by injecting only argon (Ar) gas for a certain period of time (e.g., within 10 minutes) so that a pure chromium (Cr) layer is formed at the bottom of the surface of the copper plating layer Thus, it is possible to increase the adhesion to the copper plating layer. It is preferable that the thickness of the metal deposition layer 4A is 3 to 7 µm (micrometer).

Meanwhile, when the metal deposition layer 4A is tungsten carbide (WC), the metal deposition layer 4A may be formed by a sputtering process using a high purity (eg, 99.95%) tungsten (W) target. In this sputtering process, a gas that is a mixture of high-purity argon (Ar) gas and methane (CH ₄ ) gas is injected at a predetermined flow rate (e.g., 70 sccm) and a predetermined bias (e.g., 70 ~ 100V (volt)) voltage is injected into the chamber. By adding a tungsten carbide (WC) layer may be formed. The mixing ratio of argon gas and methane gas is preferably in the range of 2:1 to 9:1. At the start of deposition of the tungsten carbide (WC) layer, sputtering is performed by injecting only argon (Ar) gas for a certain period of time (e.g., within 10 minutes) so that a pure tungsten (W) layer is formed at the bottom of the surface of the copper plating layer. Thus, it is possible to increase the adhesion to the copper plating layer. It is preferable that the thickness of the metal deposition layer 4A is 3 to 7 µm (micrometer). In addition, in a sputtering process for forming a tungsten carbide (WC) layer, a tungsten carbide (WC) target may be used instead of the tungsten (W) target.

The metal deposition layer 4A formed by the sputtering process provides a predetermined hardness and abrasion resistance to the surface of the copper plating layer 2p. The metal deposition layer 4A formed by the sputtering process has a dense structure and does not cause micro-cracks associated with the chromium plating surface formed by the conventional plating method.

The metal deposition layer 4A formed by the sputtering process according to the present invention provides excellent hardness and wear resistance compared to the hexavalent chromium plated surface according to the prior art. Table 1 below shows the metal deposition layer 4A formed by the method of manufacturing a gravure roll of the present invention, that is, chromium (Cr), chromium nitride (CrN), and chromium carbide (CrC) compared to the conventional hexavalent chromium plated surface. This is a summary of the results of the abrasion resistance test. The abrasion resistance test was conducted by using alloy steel for tool (e.g. SK11) as a wear material to reciprocate and rub the surface of the specimen, and then compare the weight of the specimen before and after the friction to check the wear rate. Frictional motion conditions were speed 60 rpm, load 1kg, friction frequency 5,000 times, friction distance 30±1mm, experiment temperature 23±2℃, experiment humidity 50±5%.

Psalter Weight before friction (g) Weight after rubbing (g) Reduced weight (g) Weight reduction rate (%) Hexavalent chromium plating 4.5562 4.5375 0.0187 0.410 Chromium (Cr) 4.7094 4.7089 0.0005 0.011 Chromium nitride (CrN) 4.4145 4.4139 0.0006 0.011 Chromium carbide (CrC) 4.8061 4.8058 0.0003 0.006

Referring to Table 1, it can be seen that the weight reduction rate is significantly lower in the metal deposition layer surface (chromium, chromium nitride, chromium carbide) according to the present invention compared to the hexavalent chromium plated surface. That is, it is confirmed that the abrasion resistance is far superior to that of hexavalent chromium plated surface.

In addition, the step of forming a surface enhancement layer (S70) may further include a step of forming a DLC layer (S73) of forming a diamond-like carbon (DLC) layer on the surface of the formed metal deposition layer 4A (FIG. 2) (h)). The diamond-like carbon (DLC) layer may constitute the surface reinforcement layer 4 together with the metal deposition layer 4A. The diamond-shaped carbon layer is a layer formed by deposition of amorphous carbon and has excellent oxidation resistance, high hardness, and low coefficient of friction. The DLC layer forming step (S73) may be selectively performed as necessary.

The method of manufacturing a gravure roll according to the present invention described in detail above provides a method of manufacturing a gravure roll having excellent wear resistance even without a conventional hexavalent chromium plating process. The method for manufacturing a gravure roll according to the present invention provides a method for manufacturing a gravure roll having excellent hardness and abrasion resistance by forming a metal deposition layer 4A by a sputtering process on the surface of a copper plating layer on which a printing pattern is formed. Therefore, it is possible to prevent environmental pollution due to hexavalent chromium, which may occur during the conventional chromium plating process, and increase the safety of the working environment. In addition, the metal deposition layer 4A formed by the sputtering process has a dense composition structure, has excellent hardness and abrasion resistance, and thus can replace the chromium plating of the conventional gravure roll. Therefore, micro-cracks and chipping defects accompanying the chromium plating layer can be eliminated.

1: core
2, 2p: copper plating layer
3, 3p: photoresist
4A: metal deposition layer
4B: diamond-shaped carbon layer
S10: core preparation stage
S20: copper plating layer formation step
S30: Photoresist coating step
S40: Exposure and development stage
S50: etching step
S60: peeling step
S70: Surface reinforcement layer formation step

Claims (8)

A copper plating layer forming step of forming a copper plating layer having a thickness of 50 to 200 μm (micrometer) on the surface of the cylindrical metal core, and
A photoresist coating step of applying a photoresist to the surface of the copper plating layer,
An exposure and development step of forming a predetermined pattern on the photoresist by removing a part of the photoresist so as to have a pattern corresponding to the printing pattern to be formed on the copper plating layer;
An etching step of forming a predetermined print pattern by etching the copper plating layer using the photoresist on which the pattern formed in the exposure and development steps is formed as a mask,
A peeling step of removing the photoresist remaining on the surface of the copper plating layer on which the printed pattern is formed,
A surface reinforcement layer forming step of forming a surface reinforcement layer for enhancing hardness and abrasion resistance of the surface of the copper plating layer in a state in which the photoresist is removed,
The surface reinforcement layer forming step includes a plasma surface treatment step of etching the surface of the copper plating layer with plasma, and a metal deposition layer having a thickness of 3 to 7 µm (micrometer) by a sputtering process on the surface of the copper plating layer treated in the plasma surface treatment step. Method of manufacturing a gravure roll comprising the step of forming a metal deposition layer to form a.
The method of claim 1,
The metal deposition layer formed in the metal deposition layer forming step is any one of chromium (Cr), chromium nitride (CrN), chromium carbide (CrC), and tungsten carbide (WC).
The method of claim 2,
When the metal deposition layer is chromium (Cr), the metal deposition layer forming step is a sputtering process using a chromium target, and manufacture of a gravure roll performed by injecting argon (Ar) gas into the chamber at a predetermined flow rate and applying a bias voltage. Way.
The method of claim 2,
1: the metallized layer is a case of chromium nitride (CrN), the metallized layer forming step is argon to the chamber by a sputtering process using a chromium target (Ar) gas and nitrogen (N ₂₎ gas 2: 1-9 A method of manufacturing a gravure roll performed by applying a bias voltage while injecting a predetermined flow rate at a mixing ratio.
The method of claim 2,
When the metal deposition layer is chromium carbide (CrC), the metal deposition layer forming step is a sputtering process using a chromium target. Argon (Ar) gas and methane (CH ₄ ) gas are added to the chamber in a ratio of 2:1 to 9:1. A method of manufacturing a gravure roll performed by applying a bias voltage while injecting a predetermined flow rate at a mixing ratio.
The method of claim 2,
When the metal deposition layer is tungsten carbide (WC), the metal deposition layer forming step is a sputtering process using a tungsten target. Argon (Ar) gas and methane (CH ₄ ) gas are added to the chamber from 2:1 to 9:1. A method of manufacturing a gravure roll performed by applying a bias voltage while injecting a predetermined flow rate at a mixing ratio.
The method of claim 2,
The step of forming the surface reinforcement layer further comprises forming a diamond-like carbon layer on the surface of the metal deposition layer formed in the metal deposition layer forming step.
A gravure roll manufactured by the method for manufacturing a gravure roll according to any one of claims 1 to 7.

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