JP2020055001A - Coating roll - Google Patents

Abstract

To resolve a trouble derived from HCr plating and allow a life longer than that of a coating roll subjected to conventional HCr plating.SOLUTION: The coating roll has a DLC film formed on a surface of a roll base material consisting of martensitic stainless steel hardened by hardening or nitriding. The hardness of the roll base material is preferably HRC20 or more; a mixing layer can also be provided between the roll base material and the DLC film; and the coating roll can be used as, for example, a gravure roll having projections and depressions having various shapes on the surface of the roll base material.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an application roll used for applying a coating material, and more specifically, to an application roll having a carbon-based material film formed on a surface of the application roll without using chrome plating (hereinafter referred to as “HCr plating”). Things.

  2. Description of the Related Art Films and glass plates having various functions (hereinafter, referred to as "functional materials") are used for mobile terminals and wearable terminals such as smartphones and tablets. These functional materials are produced by applying a coating liquid suitable for the purpose of light transmission and prevention of dirt on a film or a glass plate as a base. A coating roll is widely used for applying a coating liquid to a film or a glass plate serving as a base.

  The surface of the application roll is provided with irregularities (cells or engravings) for adjusting the amount of application of the application liquid. 1A and 1B show an example of the cell shape. FIG. 1A shows an example of a lattice-like cell, and FIG. 1B shows an example of an oblique cell. There is no particular limitation on the shape, and a shape such as shape and depth is selected according to the purpose. The shape (diameter and length) of the application roll depends on the user's machine, but is generally 30 mm or more in diameter.

  As the material of the application roll, carbon steel for machine structure (STKM13A) is mainly used, and the surface thereof is coated with HCr about 30 μm for the purpose of improving wear resistance and preventing rust. In some cases, a DLC film (carbon-based material film) is applied to the roll surface on which the HCr plating has been applied (Patent Documents 1 and 2).

JP 2013-28861 A JP 2011-157610 A

  A roll using carbon steel may generate rust, and if a carbon-based material film such as a DLC film is formed as it is, it is difficult to ensure sufficient adhesion. Plating is also performed to prevent rust. However, as shown in FIGS. 2A and 2B, a plating solution may remain inside the plating, so that the plating solution oozes out and the void Since (projections) also occur, it is difficult to obtain a normal cell shape. These obstacles contribute to a decrease in quality in manufacturing the product. Further, when the DLC coating is performed on the roll surface having the above-mentioned obstacle, a spark phenomenon such as abnormal discharge is induced during the coating, and the crater may be formed as shown in FIG.

  Some small-diameter application rolls having a diameter of 30 mm or less use SUS304, which is a kind of stainless steel. However, SUS304 is a difficult-to-process material and has a drawback that the roll shape is restricted. Further, since SUS304 is a relatively soft material, it is difficult to exhibit the characteristics of the film itself when the surface is coated with a thin carbon material such as DLC which is highly dependent on the characteristics of the base. It is.

  The present invention has been made in view of the above problems, and solves the disadvantages caused by the HCr plating that has conventionally occurred, and enables a longer life at lower cost than a conventional application roll coated with HCr. It is in.

  The coating roll of the present invention has a DLC film formed on the surface of a roll base material made of martensitic stainless steel hardened by quenching or nitriding.

The application roll of the present invention has the following effects.
(1) Since no HCr plating is used, various inconveniences derived from HCr plating do not occur.
(2) Since HCr plating is not used, no plating waste liquid is generated, and the environmental load can be reduced.
(3) Since no HCr plating is used, it is possible to shorten the delivery time of roll production and reduce the price at least by the amount required for the plating process.
(4) Shorter delivery times and lower prices of rolls can be expected to stimulate related companies and eventually the Japanese economy.
(5) Since the HCr plating is not used, the exchange of the roll due to the rupture of the void can be avoided, and the service life of the application roll can be extended (about five times that of the conventional application roll coated with HCr). .

(A) is an enlarged view of the surface of an application roll on which lattice cells are formed, and (b) is an enlarged view of the surface of an application roll on which oblique cells are formed. (A) is an enlarged view of the surface of the application roll in which a plating solution remains in the plating, and (b) is an enlarged view of the surface of the application roll in which voids are generated. FIG. 4 is an explanatory diagram when a coating roll surface becomes a crater shape. (A) is a front view showing an example of the application roll of the present invention, and (b) is an enlarged sectional view showing the structure of the surface of the application roll of the present invention. FIG. 2 is a schematic diagram illustrating an example of an apparatus used for forming a DLC film.

(Embodiment)
An example of an embodiment of the application roll of the present invention will be described with reference to the drawings. Here, a case where the application roll is a gravure roll will be described as an example. The application roll of this embodiment has an amorphous carbon film (DLC film) 2 provided on the surface of a roll base material 1. Since the HCr plating layer is not provided between the surface of the roll base material 1 and the DLC film 2, troubles caused by the HCr plating (inconveniences such as generation of voids and cracking of the DLC film 2 due to void rupture) are caused. Does not occur.

  In the present invention, a steel material that is less likely to generate rust than a general steel material and that can be hardened by quenching or nitriding is used as the roll base material 1. In this embodiment, as the roll base material 1, a martensitic stainless steel (SUS420, SUS431, SUS440C, etc.) that can be hardened by quenching or nitriding is used.

  The roll base material 1 of this embodiment is obtained by forming a martensitic stainless steel into a roll and then hardening it by quenching or nitriding. The surface hardness of the roll base material 1 is made to be HRC50 or more by the hardening treatment. The hardness of the roll base material 1 may be other than this, for example, HRC20 (Vickers strength (HV) 204) or more, preferably HRC30 (HV302) or more, and more preferably HRC50 (HV513) or more.

  The roll base material 1 may be a pipe material or a solid material. The roll base material 1 of this embodiment is a pipe material having a diameter of 60φ. When the roll base material 1 is a pipe material, as shown in FIG. 4A, the roll base material 1 is provided outside the shaft member 3 via a bearing 4. The roll base material 1 may be thicker or thinner, but preferably has a diameter of 20φ or more.

  On the surface of the roll base material 1, irregularities 5 such as cells and sculptures are formed. The unevenness 5 can be formed before or after the curing treatment. The surface of the roll base material 1 is polished or polished after the curing process. Further, when distortion (bending) occurs due to the hardening process, correction processing is performed so as to function as a roll.

The DLC film 2 formed on the surface of the roll base material 1 has a thickness of about 0.5 to 50 μm and a hardness of about 800 to 6000 HV. In forming the DLC film, a hydrocarbon gas such as CH ₄ (methane), C ₇ H ₈ (toluene), C ₂ H ₂ (acetylene), or C ₆ H ₆ (benzene) may be used as a source gas. it can. Although the structure of the DLC film 2 is not particularly specified, for reducing internal stress, Si (silicon), O ₂ (oxygen), B (boron), N ₂ (nitrogen), Cr (chromium), Ti (titanium), or the like is used. A third element may be contained.

  The application rolls shown in FIGS. 4A and 4B form the DLC film 2 directly on the surface of the roll base material 1, but are formed between the roll base material 1 and the DLC film 2 for the purpose of improving adhesion. In addition, an intermediate layer (hereinafter, referred to as “mixing layer”) different from the HCr plating layer may be provided. The mixing layer may be a layer mainly containing Si, Cr, or Ti, a layer compounded with nitrogen, or a layer containing C (carbon) or H (hydrogen) together.

  The application roll of the present invention can be manufactured through a “base material manufacturing step”, a “cleaning step”, a “mixing layer forming step”, and a “film forming step”. The “cleaning step”, the “mixing layer forming step”, and the “film forming step” can be performed using an apparatus as shown in FIG. In FIG. 5, reference numeral 6 denotes a vacuum chamber, 7 denotes an RF high-frequency power supply, 8 denotes an RF electrode, 9 denotes a high-voltage pulse power supply, and 10 denotes a gas inlet. The “cleaning step” and “mixing layer forming step” may be performed only when necessary, and may be omitted when unnecessary.

  In the base material manufacturing step, the martensitic stainless steel is formed into a roll and hardened by quenching or nitriding. After the hardening treatment, the surface of the manufactured roll base material 1 is polished or polished. When distortion (bending) occurs due to the hardening process, correction processing is performed. It is desirable that the material after quenching has an HRC of 50 or more.

In the cleaning step, the roll base material 1 manufactured in the base material manufacturing step is set in the RF electrode 8 of the vacuum chamber 6, and the vacuum chamber 6 is evacuated. In this state, the surface of the roll base material 1 is etched and cleaned with argon and hydrogen ions for the purpose of cleaning the surface of the roll base material 1 and improving the adhesion. The etching treatment can be performed by a method similar to the conventional method. The cleaning of the roll base material 1 can be performed, for example, under the following conditions.
Gas used: Ar, H ₂
Negative pulse voltage: -1 to -15 kV
RF output: 50-1500W

In the mixing layer forming step, a mixing layer not intended for HCr plating is formed on the roll surface manufactured in the base material manufacturing step. Specifically, the roll base material 1 manufactured in the base material manufacturing process is set in the RF electrode 8 of the vacuum chamber 6, and the vacuum chamber 6 is evacuated. In this state, a high-voltage pulse power supply 9 applies a negative high-voltage pulse to the roll base material 1. A raw material gas (for example, C or Si) is injected into the vacuum chamber 6 from the gas injection port 10 to generate C radicals, form a mixing layer on the surface of the roll base material 1, and adhere the DLC (adhesion). Enhance. When Si ions are implanted as a source gas, Si can serve as a primer. Further, as a source gas, a mixed gas of N ₂ , Ar (argon), CH ₄ , C ₂ H ₂ , CF ₄ (carbon tetrafluoride), C, H, and B can be injected. The formation of the mixing layer can be performed, for example, under the following conditions.
Gas used: HMDSO, HMDS, TMS (Si-based gas), CH ₄ , C ₂ H ₂
Negative pulse voltage: -1 to -15 kV
RF output: 50-1500W

In the film forming step, a DLC film 2 is formed on the surface of the roll base material 1 manufactured in the base material manufacturing step (the surface when a mixing layer is formed, the same applies hereinafter). Specifically, the inside of the vacuum chamber 6 in which the roll base material 1 is set is brought to a normal temperature (preferably about 20 ° C. to 50 ° C.) and a vacuum state. In this state, a high-frequency voltage is applied by the RF high-frequency power supply 7 to generate plasma around the roll base material 1 (specifically, around the RF electrode 8 in the vacuum chamber 6), and the high-voltage pulse power supply 9 To apply a negative high voltage pulse to the roll base material 1. After that, a raw material gas (for example, C, O ₂ ) is injected into the vacuum chamber 6 from the gas injection port 10, and the raw material gas is reacted in the vacuum chamber 6 to deposit DLC on the surface of the roll base material 1. Thereby, the DLC film 2 is formed on the roll base material 1. The DLC film 2 is not particularly specified, and may have a third element such as silicon or nitrogen in addition to carbon and hydrogen as main constituent elements. Further, the DLC film 2 may be a hydrophilic DLC film containing oxygen. The formation of the DLC film can be performed, for example, under the following conditions.
Gas used: CH ₄ , C ₂ H ₂
Negative pulse voltage: -1 to -15 kV
RF output: 50-1500W

The DLC film 2 can be formed two or more times. In this case, after the first film formation is performed under the above conditions, for example, a second film formation can be performed under the following conditions.
Gas used: C ₇ H ₈ , C ₂ H ₂
Negative pulse voltage: -1 to -15 kV
RF output: 50-1500W

  After the DLC film 2 is formed, a product is obtained without performing a process such as polishing.

  In the application roll of the present invention, even after the DLC film 2 is formed, the uneven shape of the surface of the roll base material 1 hardly changes from that before film formation, and the area ratio is 10% or less.

  The application roll of the present invention can also be used as various application rolls for applying a coating liquid to a functional material such as a film or a glass plate.

1 roll base material 2 amorphous carbon film (DLC film)
3 Shaft 4 Bearing 5 Irregularity 6 Vacuum chamber 7 RF high frequency power supply 8 RF electrode 9 High voltage pulse power supply 10 Gas inlet

Claims (4)

In an application roll provided with a DLC film,
A DLC film was formed on the surface of a roll base material made of martensitic stainless steel hardened by quenching or nitriding treatment,
An application roll, characterized in that: The coating roll according to claim 1,
The hardness of the roll base material is HRC20 or more;
An application roll, characterized in that: The coating roll according to claim 1 or 2,
A mixing layer was provided between the roll base material and the DLC film,
An application roll, characterized in that: The coating roll according to any one of claims 1 to 3,
The application roll is a gravure roll having various shapes of irregularities on the surface of the roll base material,
An application roll, characterized in that: