JPH0462056A - Peeling of regist pattern - Google Patents

Abstract

PURPOSE:To reuse a conductive plate without using organic solvent by a method wherein a regist-patterned conductive plate is brought into contact with an electrolytic solution and current is applied across electrodes facing each other to etch the conductive plate so as to peel the regist therefrom. CONSTITUTION:An electrically conductive base plate (conductive plate) which functions as an electrode in the presence of an electrolytic solution may be used, preferably with the regist patterns consisting of picture elements having an area of at most 20mm<2>. In an embodiment using the conductive plate having the regist as a cathode, the interface between the electrolytic solution and the conductive plate is changed into an acidic environment, the etching proceeds slowly from the end of the regist and the adhesive force of the regist is lowered to be peeled therefrom. Preferably, the pH value of the interface of conductive plate is at most about 2. In an embodiment using the conductive plate as a cathode, the interface is changed into an alkaline environment and the same etching takes place as above-mentioned on the aluminum base plate of a PS plate used in offset printing. In this case, it is preferable to set the pH of the interface of the conductive plate at a value of at least 2. In the case of current application printing, the electrolytic solution is not prepared separately and the printing ink may be used as such as the electrolytic solution. In this way the printing can be restarted with the ink remaining as it is after completion of the printing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a technique for peeling off a patterned resist in order to reuse a conductive substrate on which the resist has been patterned, and is applicable to printing plate reuse. It is applicable.

[Conventional technology]

Traditionally, recording peripherals for computers and other devices include printers that use various recording methods, such as laser beam and
Printers, inkjet printers, thermal transfer printers, wire dot printers and daisy-foil printers are known.

The present applicant has also previously proposed a recording method in which pattern-like adhesiveness is chemically imparted to ink and recording is performed by utilizing the difference between the adhesiveness and non-adhesiveness of this ink (Japanese Patent Laid-Open No. 63-3027
No. 9).

However, the above recording method is not suitable for large-volume printing due to cost and other considerations.

Conventionally, methods suitable for high-volume printing include lithography,
There are letterpress printing methods and gravure printing methods.

The present applicant has also filed an application for a printing method (a printing method in which printing is performed by applying voltage to ink to change the adhesion of the ink).
Patent Application No. 12617/1983) was proposed.

(Problems to be Solved by the Invention) Here, the conductive printing plate used in the above-mentioned prior art is made by patterning a resist on a conductive substrate, for example, a metal plate, or is the conductive printing plate normally used after printing is completed? Sometimes it is discarded or dipped in resist stripping solution.
The resist is peeled off and reused by applying physical stimulation to the resist to cause it to swell and dissolve.

However, although there is a disadvantage in terms of cost required for such disposal or reuse, discarding the conductive plate is not preferable, and the solvent used for removing the resist is
Since it is usually an organic solvent such as methylene chloride, trichloride, acetone, or alcohol, it is undesirable from the standpoint of environmental pollution and safety to the human body, and is also unfavorable from the standpoint of fire prevention.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a method for easily peeling off the resist of a conductive substrate having a resist pattern without using an organic solvent, thereby making it possible to reuse the resist. be.

[Means to solve the problem]

The present invention provides a method for peeling off a resist pattern provided on a conductive substrate, in which current is applied in the presence of an electrolytic solution between a pair of electrodes, one of which is the conductive substrate, and the resist pattern is separated from the conductive substrate. The above-mentioned peeling method is characterized in that the resist pattern is peeled off by etching the conductive part.According to the present invention, since the resist pattern is peeled off by etching the conductive part, without using an organic solvent,
This can be easily carried out simply by electrolysis of an electrolytic solution.

First, in the present invention, the resist pattern provided on the conductive substrate is a resist pattern mainly used as a printing plate to be subjected to a printing process, or is not limited to this in the present invention, for example, on a printed circuit board, etc. It also includes the resist pattern used. Here, the conductive substrate can be used in the method of the present invention as long as it functions as an electrode in the presence of an electrolytic solution, and for example, has a surface resistivity of 10-5Ω/sg to 103Ω/sg.
As long as it is of a certain degree, it can be carried out regardless of its shape etc. Specifically, it is a conductive substrate used as a printing plate that can be used in a printing method that forms an image by changing the adhesion of ink by applying a voltage, such as a conductive substrate made of copper plate, phosphor bronze plate, nickel, or offset plate. It is an aluminum substrate or an alloy thereof as a 28 plate that can be used for printing.

The resist pattern may be any material that can be formed as a resist on the conductive substrate, such as thermal transfer recording materials (mainly wax or resin), electrophotographic toner, vinyl polymers, and natural or synthetic materials. Polymers and the like are used.

Next, the principle of the resist pattern peeling method of the present invention will be explained.

First, a pair of electrodes is placed in an electrolytic solution, and when a voltage is applied between the electrodes and electricity is applied, the electrolytic solution undergoes electrolysis, and at the electrode interface, the hydrogen ion concentration becomes unbalanced and the pH changes as follows.

Anode: 20H--+)I20+%02+2e Cathode:
2H" +2e--+H2 As a result of this reaction, the pH at the anode interface decreases, creating an acidic atmosphere.

Here, resist pattern (hereinafter referred to as resist)
In an embodiment in which a conductive substrate (hereinafter referred to as a conductive plate) having (corroded). The surface to which the resist is attached is not etched immediately after energization, but as the etching progresses gradually from the ends of the resist toward the center, the adhesion between the resist and the conductive substrate decreases, and the resist eventually peels off. In order to efficiently proceed with the etching and peel off the resist, the pH at the interface of the conductive plate is preferably about 2 or less, and the electrolyte concentration in the electrolyte and the applied voltage are adjusted so that the pH changes within this range. etc. can be set.

On the other hand, in an embodiment in which the conductive plate is used as a cathode, the interface between the conductive plates changes to an alkaline atmosphere, and as a result, etching occurs in the same way as described above on, for example, 25-plate aluminum substrates used for offset printing, causing the resist to peel off. It becomes possible to do so.

In this case, the preferable pH at the interface of the conductive plate is about 12 or more.

Any electrolyte can be used as long as the pH can change to the above pH range at the anode interface by applying a voltage, but in the non-energized state it is neutral, weakly acidic, or weakly alkaline, and due to electrolysis when energized A solvent system that disturbs the equilibrium of hydrogen ion concentration is preferable, and a preferable specific example is a solvent system that can be used in electric printing as described below.
An aqueous solution of sodium acetate, an aqueous phosphoric acid solution, an aqueous ammonium salt solution, etc. having a concentration of 0.001 to IOM, or the like, to which an electrolyte is added if necessary, may be used. Note that the electrolytic solution may be in the form of an ink or a solution. Further, the voltage applied between the electrodes may be about 1.5 V or more, and as a result, a normal resist will peel off within about 10 to 20 minutes, although it depends on the surface resistance of the substrate.

The resist pattern is preferably composed of pixels having a surface area of 7420 mm2 or less. Area is 20ml
If it exceeds 112, depending on the shape, etching may not be performed efficiently during peeling, making peeling difficult or taking a long time, which is undesirable. Also, the area of the pixel is 2
If it is less than 0 mm2, its shape is circle, oval, rectangle,
The shape, such as a triangle, does not matter.

The conductive plate according to the present invention acts as an anode when resist is removed in current printing, which will be described later, but serves as a cathode during current printing, so in this embodiment, etching occurs when it is a cathode (under an alkaline atmosphere). It is best to use a material that does not have or does not grow easily, and is easily etched when used as an anode (under an acidic atmosphere). Preferred examples include copper, phosphor bronze, zinc, iron, chromium, nickel, and the like. Alternatively, a conductive paint made by mixing fine powder of these metals with a binder and an organic solvent may be applied. In addition to the conductive plate used in current printing, the present invention can also be applied to, for example, the 25 plate used in ordinary offset printing.In this case, since the 28 plate is made of aluminum, the plate side is used as a cathode and an alkaline atmosphere is created. This causes the aluminum to melt and the resist to be peeled off.

Next, in order to carry out the peeling method of the present invention, after printing is completed,
This may be carried out using a separately prepared electrolytic solution for resist stripping, or in the case of current printing, the used ink may be used as it is as the electrolytic solution for stripping. In this case, printing can be carried out as is after printing is completed, without removing or changing the configuration of each roll involved in the printing process, such as the printing plate and ink carrying roll. In addition, when stripping the resist using a separately provided electrolytic bath, the conductive plate is immersed in the electrolytic solution, and after energization,
Alternatively, peeling may be promoted with a resin blade or the like at the same time as electricity is applied.

Note that after peeling, a resist pattern can be formed again by cleaning the surface of the conductive substrate by a conventional method.

Hereinafter, energization printing that can suitably implement the present invention will be described. Unless otherwise specified, "parts" and "%" are based on weight.

The ink used for current printing is of a type that has adhesive properties when no voltage is applied, and whose adhesive properties disappear when voltage is applied. In this case, the ink adheres to the insulating portion of the plate and a desired recorded image is formed.

The mechanism by which the ink changes from adhesive to non-adhesive due to voltage application is thought to be as follows.

When energized by voltage application, the ink electrolyzes and generates gas, which changes its adhesion.

In this case, the ink is adjusted so that it inherently has adhesive properties, and when a voltage is applied, the ink generates gas near one of the electrodes, and this gas prevents the ink from adhering to the electrode. In order for the ink to electrolyze and generate gas, the ink contains a solvent such as water, alcohol, glycol, or a solvent in which an electrolyte is dissolved. The lower the electrical resistance of the ink, the better; the volume resistance should be 105Ω・C.
1I! It is preferable to do the following. Volume resistance is 105Ω
- If it exceeds cm, the amount of current will decrease, or a high voltage will be required to prevent the amount of current from decreasing.

Furthermore, when transferring the ink from the plate, almost the entire portion of the ink layer to which the voltage is applied moves in the thickness direction (hereinafter referred to as bulk movement).

The ink that uses the above mechanism will be explained below.

If the content of liquid such as water or alcohol in the ink is large, the cohesive force will be weak and suitable adhesion will not be obtained.

The adhesion of this ink is such that, for example, when a 2 mm thick ink is applied to a vertically erected platinum-plated stainless steel plate, the ink is substantially retained on the platinum-plated stainless steel plate. It is preferable. In addition, ink was sandwiched between two platinum-plated stainless steel plates to make the ink thickness 2 mm, and when the two platinum-plated stainless steel plates were separated from each other with no voltage applied, ink did not appear on either plate. It is preferable that they adhere to the same degree.

Ink that uses the above mechanism is basically composed of inorganic or organic fine particles and a liquid dispersion medium. The fine particles in the ink make it easier to cut the ink and improve the resolution of the image.

The above-mentioned fine particles have an average particle diameter of 100 μm or less,
Preferably, particles with a diameter of 0.1 μm to 20 μm, especially 10 μm or less, can be used, and such fine particles may be present in the ink in an amount of 1 part by weight or more, preferably 3 parts by weight to 90 parts by weight, based on 100 parts by weight of the ink. Preferably from 5 parts by weight
It can be contained in an amount of 60 parts by weight.

In addition, the liquid dispersion medium used in the ink includes water, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (weight average molecular weight, approximately 1
00-1000), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl calpitol, ethyl calpitol, butyl calpitol, ethyl carpitol acetate, diethyl calpitol, triethylene glycol monomethyl ether, triethylene glycol monomethyl ether Ethylene glycol monoethyl ether, propylene glycol methyl ether, glycerin, triethanolamine, formamide, dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, 1.3-dimethylimidazolidinone, N-methylacetamide, ethylene carbonate , acetamide, succinonitrile, dimethyl sulfoxide, sulfolane, furfuryl alcohol,
N,N-dimethylformamide, 2-ethoxyethanol, hexamethylphosphoric triamide (hexamethylphosphoric triamide), 2-nitropropane, nitroethane, γ-butyrolactone, propylene carbonate,
1.2.6-Hexandriol, dipropylene glycol, hexylene glycol, and the like can be used alone or in combination of two or more of them. The liquid dispersion medium is 40 to 95 parts by weight, more preferably 60 to 95 parts by weight, per 100 parts by weight of the ink.
It is preferable to contain 85 parts by weight.

In a preferred embodiment, in order to control the viscosity of the ink, the above-mentioned polymer soluble in the liquid dispersion medium is added to the ink material in an amount of 1 to 90 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the ink.
It can be contained in a proportion of 0 parts by weight, particularly 1 to 20 parts by weight.

Changes in ink adhesion are caused by gas generation due to electrolysis, so solvents such as water, methanol, ethanol, glycerin, ethylene glycol, and propylene glycol, or electrolytes such as sodium chloride and potassium chloride are used as liquid dispersion media. A dissolved solvent is preferably used. In particular, it is preferable to use water or a liquid containing water as the liquid dispersion medium because hydrogen gas is likely to be generated on the negative electrode side. When water and another liquid dispersion medium are mixed, the content of water is preferably 1 part by weight or more, more preferably 5 parts by weight or more, based on 100 parts by weight of the ink.

In the case of ink that generates gas through electrolysis, the fine particles contained in the ink include, in addition to those listed above, silica, fluorocarbon, titanium oxide, carbon black, fluorocarbon, and the like.

In a preferred embodiment of the ink, in consideration of the viscoelastic properties of the ink, it is preferable to use swellable fine particles that can hold the above-mentioned liquid dispersion medium. Examples of such swellable fine particles include Na-montmorillonite, Ca-montmorillonite, 3-octahedral synthetic smectite, Na-hectite, Li-hectolite, Na-duolite, and Na-montmorillonite.
- Examples include fluorinated mica such as tetrasilicic mica and Li-duolite, synthetic mica, and silica. The above-mentioned fluorinated mica can be represented by the following formula (1).

- Formula (1) % formula %) In the formula, W is Na or Li, X and Y are Mg2+Fe
”, Ni”, Mn”, /II”, Fe”, L
6-coordinate ion such as i+, Z is AI", Si", G
It represents a cation with a coordination number of 4, such as e44-, Fe'', flZl◆, or a combination thereof (A l3''/S i'ゝ).

The average particle diameter of the swellable fine particles is preferably 75 μm or less, more preferably 0.8 to 15 μm, and preferably 8 μm or less in a dry state.

If necessary, the ink can contain colorants such as carbon black and other dyes and pigments that are generally used in the fields of printing and recording. When the ink contains a colorant, the content of the colorant is 0 per 100 parts by weight of the ink.
．． 1 to 40 parts by weight, more preferably 1 to 20 parts by weight.

Further, instead of or together with the coloring material, a coloring compound that develops color upon application of voltage may be contained. In addition, the ink may contain an electrolyte, thickener, thinner, surfactant, etc. that impart conductivity.

Furthermore, it is also possible for the above-mentioned fine particles themselves to also function as a coloring material.

To obtain such an ink, for example, a liquid dispersion medium and fine particles may be mixed by a conventional method.

〔Example〕

The present invention will be explained in detail below with reference to Examples.

Example 1 A conductive plate (anode plate) whose polarity during printing is a cathode, and a counter electrode (
Anode version) was constructed as follows.

Cathode plate: As shown in FIGS. 1 and 2, an insulating pattern 4a was formed on a copper substrate using photoresist to create a cathode, which was used as a conductive plate (plate roll 3). As shown in FIG. 3, the pattern at this time had circular pixels with a diameter of about 100 μm and a space of about 20 μm.

Anode plate: As shown in FIG. 1, a platinum-plated stainless steel cylindrical roll (surface roughness Is) was used as the ink carrying roll 1 serving as an anode.

The shape of the anode plate is not limited to a cylindrical shape, but may be a flat plate or a block shape. Further, the material of the anode is preferably a conductive material such as stainless steel for the surface portion that comes into contact with the ink 2. Further, it is more preferable that the surface is plated with a noble metal such as gold, platinum, or rhodium.

The composition of the ink used is as follows.

Glycerin 200g Lithium Taeniolite (17Mg2Li(Si40.o)F2, average particle size 2.5μm) 140g Water
200gIjBF418g Cyan pigment (manufactured by West German Bayer AG, trade name: Cyanine 78F) 20g
After mixing glycerin, LiBF4, and cyan pigment with an autohomogen mixer, lithium duolite was mixed to obtain an ink.

After applying the above ink to a thickness of 2 mm on a 1 cm x 1 cm platinum-plated stainless steel plate, a platinum-plated stainless steel plate of the same size as above was placed on top of the ink, and the two platinum-plated stainless steel plates were separated under no voltage. When the gap was gradually widened and the plates were separated, ink was found to have adhered to almost the entire surface of both platinum-plated stainless steel plates.

Next, a voltage of +IOV was applied to two platinum-plated stainless steel plates with a 2 mm thick ink layer sandwiched between them, one of which was used as a cathode (earth) and the other as an anode. When the plating stainless steel plates were separated by increasing the distance between them, all of the ink adhered to the anode side, and no ink adhered to the cathode side.

Next, image formation was performed using the apparatus shown in FIG. Here, as the plate roll 3, an iron cylindrical roll with a diameter of 30 mm whose surface is plated with hard chrome is used.
The conductive printing plate 4 made of the 100 μm dots was wound on top of the copper plate, and the ink described above was placed between the ink carrying roll 1 and the coating roll 9. The ink carrying roll 1 is rotated in the direction of arrow A at a circumferential speed of 5 mn+/sec, and the cap with the coating roll 9, which is a cylindrical roll made of surface Teflon rubber that rotates in the direction of arrow E, is controlled, and the coating roll 9 is rotated in the direction of arrow A. By rotating at mm/sec, the ink layer thickness on the ink carrying roll 1 was controlled to 0.2 mm. The plate roll 3 was rotated in the direction of arrow B at a circumferential speed of 5 mm/sec.

When printing was performed with no voltage applied from the DC power supply 103 of this printing machine, no image-like printed matter was obtained, but when printing was performed with a DC voltage of 30V applied from the DC power supply 103, I was able to obtain many prints with sharp image quality. (At this time, the plate roll 3 was used as a cathode, and the ink carrying roll 1 was used as an anode).

Next, a method for removing the resist on the conductive plate after printing is completed will be described.

After the blanket cylinder 5 is separated from the plate roll 3 while the ink is carried on the ink carrying roll 1, the DC power supply 10
3, a DC voltage (40 V) was applied to the plate roll 3 using the plate roll 3 as an anode and the ink carrying roll 1 as a cathode. While applying the voltage, the plate roll 3 was rotated in the direction of arrow B at a circumferential speed of 5 mm/sec, and the ink carrying roll 1 was rotated in the direction of arrow A at a peripheral speed of 5 mm/sec.
When the plate was rotated at a circumferential speed of mm/sec, the resist image on the conductive plate was peeled off in about 7 minutes.

After the resist was removed, the surface of the conductive plate was cleaned, then resist was applied again and patterned.

Example 2 After printing was carried out in the same manner as in Example 1 using the same plate, the resist was removed as follows.

First, the plate roll 3 was removed from the apparatus shown in FIG. 1 and immersed in an electrolytic bath 15 shown in FIG. As the electrolytic solution 14, the ink composition described above may be used, or an electrolytic solution used for ordinary electrolysis of water may be used. In this example, a 0.1M sodium acetate aqueous solution was used as the electrolytic solution 14.

After the plate roll 3 is immersed, a platinum plate is used as the counter electrode 13, and a potential of 30
When V was applied (the counter electrode 13 was the cathode and the plate roll 12 was the anode), the resist image on the conductive plate was peeled off in about 5 minutes.

After the resist was removed, the surface of the conductive printing plate was cleaned, then resist was applied again and patterning was completed.

Example 3 After printing was carried out in the same manner as in Example 1 using the same plate, the resist was removed as follows.

First, after removing the conductive printing plate 4 from the plate roll 3, it was immersed in the same electrolytic bath as in Example 2. As in Example 2, a platinum plate was used as the counter electrode, 20V was applied between the counter electrode and the conductive substrate with a power supply interposed (the counter electrode was the cathode, the conductive substrate was the anode), and the resist surface of the conductive printing plate was covered with resin. When the resist image was rubbed lightly with a blade, the resist image was peeled off in about 3 minutes.

After the resist was removed, the surface of the conductive printing plate was cleaned, then resist was applied again and patterning was completed.

Example 4 The same patterning as in Example 1 was carried out on Nekative PS plate FNS manufactured by Fuji Photo Film ■ to prepare an offset printing plate. This plate was attached to a Sun Offset offset printing machine manufactured by San Printing Machinery ■, and printing was performed. After printing is finished,
This plate was removed and immersed in the same electrolytic bath as in Example 2,
When the resist was removed by applying electricity in the same manner except that the plate side was used as a cathode and the counter electrode side was used as an anode, the resist image on the aluminum plate was removed in about 5 minutes.

After the resist was removed, the surface of the PS plate was cleaned, then resist was applied again and patterning was completed.

〔Effect of the invention〕

The resist stripping method of the present invention uses an organic solvent to remove the resist by bringing a conductive plate on which the resist has been patterned into contact with an electrolytic solution and passing a current between the opposing electrodes and etching the conductive plate. This makes it possible to reuse the conductive plate while avoiding environmental pollution, human safety, and fire safety issues.

By changing the polarity of the conductive plate, the present invention can be applied not only to current printing but also to a conductive plate used for offset printing. It is excellent in practical use, as the resist can be removed simply by changing the polarity of the resist.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the configuration of the printing device used in the example, FIG. 2 is a schematic perspective view of the conductive printing plate, and FIG. 3 is an explanatory diagram showing the configuration of the resist pattern on the conductive plate. , FIG. 4 is a schematic perspective view of the electrolytic cell used for resist stripping. Ink carrying roll Ink (recording material) Plate roll Conductive plate 4a Resist area (image area) 4b Conductive area (non-image area) Blanket cylinder Impression cylinder Recording paper transfer Image coating roll Power source Resist pattern configuration Dot Power source plate roll Counter electrode electrolyte electrolyte bath Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. A method for peeling off a resist pattern provided on a conductive substrate, the method comprising: applying electricity in the presence of an electrolytic solution between a pair of electrodes, one of which is the conductive substrate; The above-mentioned peeling method, characterized in that the resist pattern is peeled off by etching the conductive portion of the conductive substrate. 2. The peeling method according to claim 1, wherein the conductive substrate is a printing plate. 3. The peeling method according to claim 1 or 2, wherein the electrolytic solution is a solution that causes a pH change when energized. 4. The peeling method according to claim 3, wherein the electrolytic solution is an ink whose adhesion changes depending on the polarity of the applied voltage. 5. The peeling method according to any one of claims 1 to 4, wherein the resist pattern is composed of pixels having an area of 20 mm^2 or less.