KR100330914B1 - Printing ink for forming pattern on a surface of stone, a method of forming pattern on a surface of stone, and a stone manufactured therefrom - Google Patents

Abstract

The present invention provides a printing ink capable of forming a pattern on a stone surface vividly and delicately without spreading a pattern while maintaining the texture and gloss of the stone surface in a natural state, and a method of forming a pattern on such stone surface; The present invention relates to a stone manufactured by such a pattern forming method, wherein the printing ink according to the present invention includes 25 to 35% by weight of an oil dye, 15 to 30% by weight of an organic solvent, 20 to 30% by weight of a plasticizer, and 15 to 15% of a resin. It consists of 30% by weight, the pattern forming method according to the invention, the step of polishing the surface of the stone, oil dyes 25-35% by weight, organic solvent 15-30% by weight, plasticizer 20-30% by weight and Silk screen printing a predetermined pattern on the stone surface using a printing ink composed of 15 to 30% by weight of resin, and preheating the stone printed on the surface of the pattern for 20 minutes to 1 hour at 50 to 100 ° C. Step 12, the stone A heating step of infiltrating the printing ink into the stone by further heating at 0 to 170 ° C. for 30 minutes to 7 hours, cooling the stone to room temperature, and removing the coating film remaining on the stone surface.

Description

PRINTING INK FOR FORMING PATTERN ON A SURFACE OF STONE, A METHOD OF FORMING PATTERN ON A SURFACE OF STONE, AND A STONE MANUFACTURED THEREFROM}

The present invention relates to a printing ink for forming a pattern on a stone surface, a method for forming a pattern on a stone surface, and a stone produced by the method. In particular, the spread of the pattern is maintained while maintaining the texture and gloss of the stone surface in a natural state. The present invention relates to a printing ink capable of forming a pattern on a stone surface vividly and delicately, a method of forming a pattern on such a stone surface, and a stone manufactured by such a pattern forming method.

As the living conditions of modern people have improved dramatically, various attempts have been made to decorate the surrounding space more elegantly and luxuriously using various ornaments and artworks to satisfy human's original desire for beauty. In order to meet the demands of modern people, various forms of ornaments and works of art have been developed and marketed. In particular, among such ornaments and artworks, interior and exterior materials of buildings, works of art such as murals, ink paintings and calligraphy, and photographs such as portraits and art photography are most widely used.

Such ornaments and arts are generally obtained by printing specific letters, pictures, photographs, etc. by various printing techniques using printing inks on the surface of a certain object having a material such as paper, cloth, ceramics, plastic, metals, etc. These ornaments and artworks are so prevalent around life that they do not meet the tastes of modern people, they do not provide a luxurious atmosphere and unique decorative effects, they are not durable and can only be used for limited purposes. Instead, the trend is to favor stone ornaments and artwork.

As described above, the ornaments and art works using the stone are manufactured by printing a predetermined pattern on the surface of the stone, or by carving or dyeing the surface of the stone. As a representative conventional technique related thereto, the following techniques may be mentioned.

First, a transfer printing technique is a method of forming a pattern on a stone surface by transfer-printing a pattern on a stone surface and then resin-coding the stone surface on which the pattern is printed to protect the printing surface. However, this prior art has a fatal disadvantage that the resin is coded on the top layer of the stone, leaving the texture and luster of the resin, rather than the texture and luster of the stone, remaining on the surface, resulting in the loss of natural texture and inferior natural beauty of the stone surface. .

Secondly, Yin-Yang dot carving technology, as disclosed in the Republic of Korea Patent Application No. 98-41553, the hammer punch of a computer-operated robot is engraved into the stone surface by engraving the dot on the stone surface by a program embedded in the computer As a method of forming a pattern and a technology developed by Japan's Sunlight Industry Co., Ltd., a photosensitive resin is applied to a stone surface, and then an original film is placed on the stone and irradiated with ultraviolet rays to correspond to a pattern other than the pattern. The photosensitive resin is cured and sand is sprayed at a high pressure to form a pattern by engraving the stone surface part corresponding to the dot of the pattern part by engraving. However, in this prior art, since the surface of the stone is engraved intaglio, not only natural beauty falls and no realistic description is obtained, but also the obtained pattern is coarse, and it is technically difficult to form a vivid and delicate pattern. have.

Third, as a whole surface dyeing technique of stone, a stone is dipped in a salt solution in which a dye is dissolved to dye the whole surface of the stone. However, such a prior art also has a problem that it is impossible to form a vivid and delicate pattern at all.

After all, the present invention has been made to overcome the above-mentioned limitations of the prior art, and the main object of the present invention is to be clear and delicate without spreading patterns while maintaining the texture and gloss of the stone surface in a natural state. To provide a printing ink that can form a pattern on the stone surface.

In addition, another object of the present invention, by using the printing ink of the present invention described above, while maintaining the texture and gloss of the surface of the stone in its natural state, while forming the pattern on the stone surface vividly and delicately without spreading the pattern To provide a way to do it.

Further, another object of the present invention is to provide a stone having a pattern formed on the surface obtained by the aforementioned pattern formation method of the present invention.

The present inventor actively solves the problems of the prior art described above, and can form a pattern on the stone surface clearly and delicately without spreading the pattern while maintaining the texture and gloss of the stone surface in a natural state. As a result of many years of research to develop the technology, when the printing ink having a specific composition is used to form a pattern on the stone surface according to the optimum manufacturing conditions, the printing ink penetrates into the stone and the predetermined pattern is formed into the stone. By forming from the surface to the inside, the inventors discovered that the above object of the present invention can be achieved, and studied intensively to complete the present invention.

1 is a schematic process diagram for a method of forming a pattern on a stone surface according to the present invention,

2 is a plan view and a cross-sectional view of an original pattern used when forming a pattern on the stone surface according to the present invention, and a stone patterned on the surface according to the present invention using the original pattern.

Explanation of symbols on the main parts of the drawings

10: stone 20: printing ink

30: Glyph Form Document

In order to achieve the above object of the present invention, the printing ink for pattern formation on the stone surface according to the present invention,

It is characterized by consisting of 25 to 35% by weight of an oil dye, 15 to 30% by weight of an organic solvent, 20 to 30% by weight of a plasticizer, and 15 to 30% by weight of a resin.

In addition, the pattern forming method of the stone surface according to the present invention,

Polishing the surface of the stone,

Silk-screen printing a predetermined pattern on the stone surface using a printing ink composed of 25 to 35% by weight of an oil dye, 15 to 30% by weight of an organic solvent, 20 to 30% by weight of a plasticizer, and 15 to 30% by weight of a resin. Steps,

Preheating the stone with the pattern printed on the surface at 50 to 100 ° C. for 20 minutes to 1 hour,

A main step of heating the stone at 120 to 170 ° C. for 30 minutes to 7 hours to infiltrate the printing ink into the stone;

Cooling the stone to room temperature, characterized in that it comprises the step of removing the coating film remaining on the stone surface.

Moreover, the stone with the pattern formed on the surface according to the present invention,

The surface of the stone was polished, and predetermined on the surface of the stone using a printing ink composed of 25 to 35% by weight of an oil dye, 15 to 30% by weight of an organic solvent, 20 to 30% by weight of a plasticizer, and 15 to 30% by weight of a resin. After silk screen printing the pattern of, preheated at 50 to 100 ℃ for 20 minutes to 1 hour, and further heated at 120 to 170 ℃ for 30 minutes to 7 hours to infiltrate the printing ink into the stone, and then to room temperature It is produced by cooling and removing the coating film remaining on the stone surface.

According to the manufacturing method of the present invention, the ink silk-screen-printed in a predetermined pattern on the surface of the stone, while preheating, the organic solvent contained in the printing ink is volatilized, the printing ink is between the particles and the particles inside the stone It has a suitable viscosity to penetrate through the micropores present. Subsequently, as the printing ink is absorbed through the pores connected between the particles and the particles inside the stone, the infiltration proceeds as the heating process progresses. As time passes, the plasticizer is volatilized and removed from the printing ink, thereby penetrating the printing ink. When it is stopped and cooled to room temperature, dyes and resins in the printing ink are solidified and remain to a depth of about 0.5 to 2 mm from the stone surface. Next, when the coating film of the printing ink remaining on the stone surface is removed, the stone of the present invention having a pattern formed on the surface is obtained.

Hereinafter, a printing ink for forming a pattern on a stone surface according to the present invention, a method for forming a pattern on a stone surface, and a stone manufactured by the method will be described in more detail with reference to the accompanying drawings.

As mentioned above, the printing ink for pattern formation of the stone surface which concerns on this invention is 25-35 weight% of oil dyes, 15-30% weight of an organic solvent, 20-30 weight% of a plasticizer, and 15-30% weight of resin It consists of.

In the printing ink composition of the present invention described above, the organic solvent serves to dissolve the dye and to make the printing ink have a viscosity suitable for printing on the stone surface, and the plasticizer has compatibility with the resin. It provides fluidity or flexibility to the printing ink so that the printing ink has a suitable viscosity to penetrate through the fine pores present between the particles and the particles inside the stone. The resin is compatible with the dye and at the same time gives the printing ink adhesion and By controlling the viscosity, the printing ink does not spread sideways when penetrating through the fine pores in the stone, and at the same time serves to fix the dye after the heat treatment process.

In the printing ink composition described above, an oil dye, for example, a metal complex dye, a solvent dyestuff, or the like may be used as the dye, and particularly, excellent solubility in various kinds of organic solvents may be obtained. It is preferable to use a metal complex dye having excellent light stability because it does not discolor even when exposed to the outside air for a long time. Representative examples of such metal complex dyes include Neozapon (trade name) series of BASF, and Oriko Colors (trade name) series of Orient Chemical, Ltd., In particular, Neozapon YELLOW 157, RED 335, BLUE 807 and BLACK X51 and Orico color YELLOW 210, RED 234, RED 236, BLUE 266 and BLACK 280 are used. Such a metal complex dye is obtained by forming a pattern on a stone surface using a printing ink employing these metal complex dyes due to chemical bonding of metals such as copper, chromium and cobalt with dye molecules such as phthalocyanine. Discoloration does not occur even if the product is exposed to light for a long time. Meanwhile, as the organic solvent, it is preferable to use MIBK (Methyl Isobutyl Ketone) or MEK (Methyl Ethyl Ketone), and as a plasticizer, DBP (Dibutyl Phthalate), BBP (Butyl Benzyl Phthalate) and DBS (Dibutyl Sebacate) ), DOP (Dioctyl Phthalate), DOS (Dioctyl Sebacate) or DOA (Dioctyl Adipate) is preferably used, and the resin is ester gum (Roster) or rosin (Ketone Resin). It is preferable.

At this time, when the addition amount of the above-mentioned oil dye is less than 25% by weight, there is a problem that the pattern printed on the surface of the stone is blurred, and when larger than 35% by weight, the amount of the resin is relatively small and the viscosity of the printing ink is decreased. Since it is reduced, the penetration of the printing ink spreads sideways through the pores inside the stone, there is a disadvantage that it is difficult to obtain a clear pattern. In addition, when the added amount of the organic solvent is less than 15% by weight, not only complete dissolution of the dye is achieved, but also the viscosity of the printing ink becomes large, making it difficult to silkscreen print on the stone surface, and when it is larger than 30% by weight, The printing ink is so thin that it is also difficult to silk screen print on the stone surface. If the amount of plasticizer added is less than 20% by weight, the fluidity of the printing ink is reduced and it is difficult to penetrate into the stone. Thus, the pattern of the stone surface obtained after the manufacturing process is blurred. Since the fluidity of the ink is so large that the printing ink spreads laterally when the ink penetrates through the fine pores inside the stone, it is difficult to obtain a clear pattern by spreading the pattern of the stone surface obtained after the manufacturing process. Moreover, when the amount of resin added is less than 15% by weight, the viscosity of the printing ink is so small that it spreads laterally through the pores inside the stone during penetration of the printing ink, so that the pattern of the obtained stone surface spreads and it is difficult to obtain a clear pattern, If it is larger than 30% by weight, the viscosity of the printing ink is increased, so that it is difficult to penetrate into the stone, and thus the pattern of the stone surface is blurred.

Using the printing ink composition of the present invention, a method for forming a pattern on the stone surface by dividing step by step as follows:

1) Polishing Process :

The surface of the stone is polished to a degree suitable for printing with printing ink. At this time, as the stone can be used stone of a variety of materials according to the taste of the end consumer, it is preferable to use marble.

2) Printing process :

As shown in Fig. 1A, a predetermined pattern is silk-screen printed on the surface of the stone 10 using the printing ink 20 of the present invention described above by a known method.

3) Preheating Process :

In the printing process described above, the stone 10 printed on the surface of the pattern is preheated at 50 to 100 ° C. for 20 minutes to 1 hour to volatilize the organic solvent contained in the printing ink 20, thereby printing ink 20. ) Has a suitable viscosity to penetrate through the fine pores present between the particles and the particles inside the stone (10).

In the method for forming the pattern of the stone surface according to the present invention, the printing ink may be heated by integrating the preheating step and the main heat step described below into one step. However, in the case of using such a method, printing printed on the stone surface is performed. The viscosity of the ink is so small that when the ink penetrates, it spreads sideways through the pores inside the stone, and as a result, the pattern of the obtained stone surface spreads and a clear pattern cannot be obtained, so the heating process is separated into a preheating process and a preheating process. By first volatilizing the organic solvent contained in the printing ink in the preheating process, the printing ink has an appropriate viscosity so that the printing ink can penetrate through the pores inside the stone without spreading sideways. .

In the above preheating step, when the preheating temperature is lower than 50 ° C., there is a problem that the organic solvent does not volatilize to the desired viscosity, and when the preheating temperature is higher than 100 ° C., the heating step is a preheating step and a preheating step. There is no sense to separate. In addition, when the preheating time is less than 20 minutes, since the organic solvent is hardly volatilized to the desired viscosity, and the organic solvent is volatilized within 1 hour, the preheating time exceeding 1 hour is meaningless.

4) Thermal process :

As shown in FIG. 1B, the preheating stone 10 is further heated at 120 to 170 ° C. for 30 minutes to 7 hours to infiltrate the printing ink 20 into the stone. At this time, when the printed coating film is penetrated through the pores inside the stone, without penetrating sideways, penetrates to the depth of about 0.5 to 2mm from the surface of the stone 10 to the inside, and as time passes, the plasticizer is volatilized and printed By being removed from the ink, penetration of the printing ink is stopped, leaving the printing ink, and more specifically, the dye commonly used in the resin, to a depth of about 0.5 to 2 mm.

In this main heat process, when the heat temperature is lower than 120 ° C., the printing ink does not penetrate well into the stone, and the pattern of the obtained stone surface is clouded. When the heat temperature is higher than 170 ° C., the dye is decomposed or the stone is ruptured. There is a problem that can be. In addition, when the above-mentioned heat time is less than 30 minutes, printing ink does not penetrate into the stone well, resulting in blurring of the pattern of the obtained stone surface, and when it exceeds 7 hours, the plasticizer is before 7 hours. Since the ink is already volatilized, and the printing ink does not penetrate, the color of the pattern does not increase in proportion to time.

5) Coating removal process :

In the above process, the stone 10 in which the pattern is formed is cooled to room temperature, and the coating film remaining on the surface of the stone 10 is removed to obtain the stone of the present invention in which the pattern is formed on the surface, as shown in FIG. 1C.

Figure 2a shows the original pattern 30 used in forming a pattern on the surface of the stone 10 in accordance with the present invention, Figures 2b and 2c of the present invention described above using this original pattern 30 According to the pattern forming method is a plan view and a cross-sectional view of the stone 10 has a pattern is formed on the surface, respectively.

According to the pattern forming method of the present invention, while maintaining the texture and gloss of the surface of the stone in its natural state, it is possible to obtain a stone with a pattern formed on the surface clearly and delicately without spreading the pattern.

Hereinafter, the present invention will be described in more detail with reference to a preferred embodiment of the method for forming the pattern of the stone surface according to the present invention. These examples are given only to further illustrate the present invention, and it will be apparent to those skilled in the art that the present invention is not limited by these embodiments.

Example 1:

The surface of the marble was polished flat, 30% by weight oily dye, 23% by weight MIBK, D.B.P. Using a printing ink consisting of 25% by weight and 22% by weight of ester gum, silk screen printing a predetermined pattern on the marble surface, then preheating at 75 ° C for 45 minutes, further heating at 140 ° C for 3 hours, and then at room temperature Was cooled, and the coating film remaining on the marble surface was removed to obtain a marble of the present invention having a pattern on the surface.

In the marble obtained in the present embodiment, the texture and gloss of the marble surface were maintained in a natural state, and it was confirmed that a pattern was formed on the marble surface clearly and delicately without spreading of the pattern.

When the marble was cut in the longitudinal direction and visually confirmed the cross section of the marble, it was found that the printing ink penetrated to a depth of about 1 mm.

Example 2 :

30% by weight oily dye, 22% by weight MEK, D.O.P. A marble of the present invention having a pattern on the surface thereof was obtained in the same manner as in Example 1, except that a printing ink composed of 25 wt% and 23 wt% rosin was used.

Example 3 :

Oily dye 30% by weight, MEK 23% by weight, D.B.S. A marble of the present invention having a pattern on the surface thereof was obtained in the same manner as in Example 1 except that a printing ink composed of 24 wt% and 23 wt% of ketone resin was used.

Example 4:

Oily dye 25% by weight, MIBK 30% by weight, D.B.P. A marble of the present invention was obtained in the same manner as in Example 1 except that a printing ink composed of 20 wt% and 25 wt% of ester gum was used.

Example 5:

Oily dye 35% by weight, MIBK 15% by weight, D.B.P. A marble of the present invention having a pattern on the surface was obtained in the same manner as in Example 1, except that a printing ink composed of 30% by weight and 20% by weight of ester gum was used.

Example 6:

Oily dye 30% by weight, MIBK 20% by weight, D.B.P. A marble of the present invention was obtained in the same manner as in Example 1 except that a printing ink composed of 20 wt% and 30 wt% of ester gum was used.

Example 7:

Oily dye 30% by weight, MIBK 25% by weight, D.B.P. A marble of the present invention having a pattern on the surface was obtained in the same manner as in Example 1, except that a printing ink composed of 30% by weight and 15% by weight of ester gum was used.

Example 8:

The pattern was applied in the same manner as in Example 1 except for silk screen printing a predetermined pattern on the marble surface, then preheating at 50 ° C. for 1 hour and further heating at 120 ° C. for 30 minutes. The formed marble of the present invention was obtained.

Example 9:

Silk-printed a pattern on the surface of marble, followed by preheating at 100 ° C. for 20 minutes, and further heating at 170 ° C. for 7 hours, in the same manner as in Example 1, to provide a pattern on the surface. The formed marble of the present invention was obtained.

Comparative Example 1:

20% by weight oily dye, 35% by weight MIBK, D.B.P. Except having used the printing ink which consists of 15 weight% and 30 weight% of ester gums, it carried out similarly to Example 1, and obtained the marble with the pattern on the surface.

Comparative Example 2:

Oily dye 30% by weight, MIBK 10% by weight, D.B.P. Except having used the printing ink which consists of 40 weight% and 20 weight% of ester gums, it carried out similarly to Example 1, and obtained the marble with the pattern on the surface.

Comparative Example 3:

Oily dye 30% by weight, MIBK 35% by weight, D.B.P. A marble having a pattern on the surface was obtained in the same manner as in Example 1, except that a printing ink composed of 25% by weight and 10% by weight of ester gum was used.

Comparative Example 4:

Silk-printed a pattern on the surface of marble, then preheated at 40 ° C. for 1 hour, and further heated at 140 ° C. for 3 hours, except that the pattern was formed on the surface. Obtained marble was obtained.

Comparative Example 5:

The pattern was applied in the same manner as in Example 1 except for silk screen printing a predetermined pattern on the marble surface, then preheating at 75 ° C. for 45 minutes and further heating at 100 ° C. for 7 hours. Obtained marble was obtained.

Comparative Example 6:

The pattern was applied in the same manner as in Example 1 except for silk screen printing a predetermined pattern on the marble surface and then preheating at 75 ° C. for 45 minutes and further heating at 180 ° C. for 4 hours. Obtained marble was obtained.

The marbles prepared in Examples 2 to 9 and Comparative Examples 1 to 6 were visually inspected for the intensity of printed patterns, whether they spread, whether silk screen printing was possible, whether decomposition of dyes or rupture of stones. The results are shown in Table 1 below.

division The intensity of the pattern Whether the pattern is spread Whether silk screen printing is possible Whether to dissolve dyes or burst stones Example 2 Dark Does not spread possible × Example 3 Dark Does not spread possible × Example 4 Dark Does not spread possible × Example 5 Dark Does not spread possible × Example 6 Dark Does not spread possible × Example 7 Dark Does not spread possible × Example 8 Dark Does not spread possible × Example 9 Dark Does not spread possible × Comparative Example 1 blur spread difficulty × Comparative Example 2 blur spread difficulty × Comparative Example 3 blur Does not spread difficulty × Comparative Example 4 blur spread possible × Comparative Example 5 blur Does not spread possible × Comparative Example 6 blur Does not spread possible ○

From the results of Table 1 above, when a printing ink having a composition outside the printing ink composition of the present invention is used, or when the pattern is formed under conditions outside the manufacturing conditions for the pattern forming method of the present invention, the pattern printed on the marble surface It was confirmed that the cloudiness, the pattern spread, the silk screen printing was difficult, or the decomposition of the dye or the rupture of the stone occurred.

As described and demonstrated in detail above, according to the present invention, unlike the prior art, while maintaining the texture and gloss of the surface of the stone in its natural state, while forming the pattern on the stone surface vividly and delicately without the spread of the pattern can do.

Stones formed with patterns on the surface obtained in accordance with the present invention, because the patterns formed on the surface of the stone combined with the natural beauty and inherent beauty of the stone, providing an elegant and luxurious atmosphere, ornaments and art, in particular, It can be widely applied to a wide range of fields such as interior and exterior materials, works of art such as murals, ink paintings and calligraphy, and photographs such as portrait photography and art photography.

On the other hand, in the above description, although the printing ink for forming the pattern on the stone surface according to the present invention is said to be composed of an oil dye, an organic solvent, a plasticizer and a resin, the printing ink of the present invention is not limited to this, and if necessary Other materials may be added, some of these components may be replaced by other materials having equivalent physical and chemical properties, or some of these components may be omitted.

In addition, in the printing ink according to the present invention, it is mentioned that one specific compound of an organic solvent, a plasticizer and a resin is used, respectively, but two or more kinds of the compounds exemplified above for the organic solvent, the plasticizer and the resin are mixed as necessary. Of course it can be used.

Furthermore, in the above-described pattern formation method of the present invention, the heating process is carried out by separating the preheating step and the main heating step, but even if the pattern is somewhat spread, in order to simplify the process or the complexity of the type and pattern of the raw materials used. In accordance with the present invention, it will be apparent to those skilled in the art to which the present invention pertains.

Claims (6)

25 to 35% by weight of metal complex dyes, 15-30% by weight of at least one organic solvent selected from MIBK and MEK, D.B.P., B.B.P., D.B.S., D.O.P., D.O.S. And D.O.A. 20 to 30% by weight of one or more plasticizers selected from A printing ink for pattern formation on a stone surface, comprising 15 to 30% by weight of at least one resin selected from ester gum, rosin, and ketone resins. delete delete delete Polishing the surface of the stone, 25 to 35% by weight of the metal complex dye, 15 to 30% by weight of at least one organic solvent selected from MIBK and MEK, and D.B.P., B.B.P., D.B.S., D.O.P., D.O.S. And D.O.A. Silk screen printing a predetermined pattern on the stone surface using a printing ink composed of 20 to 30% by weight of one or more plasticizers selected from among and 15 to 30% by weight of one or more resins selected from ester gums, rosin and ketone resins. To do that, Preheating the stone with the pattern printed on the surface at 50 to 100 ° C. for 20 minutes to 1 hour, A main step of heating the stone at 120 to 170 ° C. for 30 minutes to 7 hours to infiltrate the printing ink into the stone; Cooling the stone to room temperature, and removing the coating film remaining on the stone surface, stone pattern forming method. The surface of the stone was polished, 25 to 35% by weight of the metal complex dye, 15 to 30% by weight of one or more organic solvents selected from MIBK and MEK, D.B.P., B.B.P., D.B.S., D.O.P., D.O.S. And D.O.A. Silk screen printing a predetermined pattern on the stone surface using a printing ink composed of 20 to 30% by weight of one or more plasticizers selected from among and 15 to 30% by weight of one or more resins selected from ester gums, rosin and ketone resins. Then, preheated at 50 to 100 ° C. for 20 minutes to 1 hour, and further heated at 120 to 170 ° C. for 30 minutes to 7 hours to infiltrate the printing ink into the stone, and then cooled to room temperature and onto the stone surface. Stone formed with a pattern on the surface, characterized in that produced by removing the remaining coating film.