JP3582981B2 - Manufacturing method of identification display - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an identification display body in which a fluororesin molded body provided with an identification display is laminated with a transparent resin sheet.
[0002]
[Prior art]
An identification display such as a barcode is currently used in various industrial and logistics fields, and is used in a production line such as a factory for process management such as identification and sorting of articles. In addition, since a semiconductor manufacturing line uses a strongly acidic or strongly alkaline chemical or is in an environment of a high temperature atmosphere, an identification display such as a bar code is required to have chemical resistance and heat resistance. In order to satisfy this requirement, an identification indicator is attached to a product or container using a fluororesin such as polytetrafluoroethylene (hereinafter referred to as “PTFE”) having excellent heat resistance, chemical resistance, mechanical strength, and the like. Is used.
[0003]
Examples of these identification displays include a fluororesin surface such as PTFE, on which a bar code or the like is printed, and a copolymer of PTFE and perfluoroalkyl vinyl ether (hereinafter referred to as “PFA”) around the surface of the fluororesin. ), A copolymer of PTFE and hexafluoropropylene (hereinafter, referred to as “FEP”) or a copolymer of PTFE, hexafluoropropylene, and perfluoroalkylvinylether (hereinafter, referred to as “EPE”). (Laminated) or the like wrapped with a fluororesin. Then, for example, an identification display body laminated with PFA is obtained by sandwiching a PTFE film on which a barcode is printed between two PFA sheets and putting the two into a mold, and fusing the two PFA sheets to each other. It is manufactured by.
[0004]
However, fluororesins such as PTFE are non-adhesive, exhibit water and oil repellency, and are less likely to adhere to ink. Therefore, by performing physical or mechanical treatment such as plasma treatment or sputtering treatment to form fine irregularities on the surface, or by performing chemical etching such as treatment with a solution of metal sodium in liquid ammonia, the surface is subjected to chemical etching. The activation makes it easy for the ink to adhere to each.
[0005]
Japanese Patent Application Laid-Open No. 5-50028 discloses an identification method including a step of applying a coloring material to the surface of a synthetic resin molded article such as PTFE or PEEK resin, and then heating the molded article to a temperature lower than the melting point of the synthetic resin molded article. A method for producing a labeled synthetic resin product is disclosed, and when an unfired PTFE molded article is used, the unfired PTFE film is subjected to a temperature of 180 ° C or higher and a melting point of PTFE or lower before the heating step. The heat treatment improves the adhesion of the ink.
[0006]
[Problems to be solved by the invention]
However, if the surface has minute irregularities, it is difficult to perform fine printing, and it is not possible to cope with a bar code expected to be reduced in size or a two-dimensional bar code, which is expected in the future. In addition, the treated surface of the fluorine-based synthetic resin treated with a solution of metallic sodium dissolved in liquid ammonium becomes brownish, the identification mark is difficult to read, the appearance deteriorates, and when the treated surface is exposed to sunlight for a long time, it adheres. There is a problem that the property is reduced. Further, even if the preliminary treatment before the heating step described in JP-A-5-50028 is performed, the unbaked PTFE film still has poor ink adhesion, and it is difficult to perform precise and fine printing. Met. Further, the same document discloses a process in which a coloring material is applied to the surface of an untreated synthetic resin molded body and then subjected to a heat treatment at a temperature equal to or lower than the melting point of the synthetic resin. Synthetic resin (previous) has low crystallinity and low surface free energy, so the ink adhesion is poor, and it has been difficult to perform precise and fine printing.
[0007]
Accordingly, it is an object of the present invention to provide a method of manufacturing an identification display body that has a clear identification display and can be easily read by various readers.
[0008]
[Means for Solving the Problems]
Under such circumstances, the present inventors have conducted intensive studies on the above-mentioned problems associated with the chemical etching treatment, and as a result, have completed the present invention. That is, the present invention provides a step of printing a predetermined identification mark on the surface of a chemically etched fluororesin molded article with an ink mixed with a coloring material, and applying the fluorine resin molded article on which the identification mark is printed to an oxygen atmosphere. Medium , a step of heating at a temperature higher than the glass transition point of the fluororesin molded body and lower than the melting point to decolorize the chemically etched surface portion that is not marked with an identification mark, and substantially removes the surface of the fluororesin molded body. And laminating a transparent resin sheet to form a laminate, and then heat-compressing the laminate with a mold and fusing the laminate to provide a method for producing an identification display.
[0009]
In the present invention, the surface of the fluororesin molded body is activated by the chemical etching treatment, and the ink is easily adhered, while the surface is discolored to brown. Then, the fluororesin molded body with the identification is heat-treated in an oxygen atmosphere at a temperature equal to or higher than the glass transition point of the fluororesin and lower than the melting point, so that the chemical etching layer without the identification is oxidized. The active carbon in the chemical etching layer is removed as carbon dioxide. Therefore, the surface is decolorized and the identification display is sharpened. On the other hand, the chemical etching layer with the identification mark is protected by the ink components such as pigments and binders included in the identification mark, and is not oxidized by the heat treatment. Further, the heat treatment has an action of removing organic components contained in the ink for identification display in addition to the decolorizing action. That is, by the heat treatment, the organic component contained in the ink for identification display is melted, soaks into the chemical etching layer of the identification display portion, and is removed by decomposition vaporization or vaporization, or carbonized to form a strong bond with the chemical etching layer. Stick to. On the other hand, the pigment contained in the ink for identification is attached or fixed to the surface of the chemical etching layer to stabilize the identification. As described above, both the decolorizing action and the organic component removing or carbonizing action can provide a clear identification display having excellent heat resistance stability.
[0010]
Further, the present invention provides a step of printing a predetermined identification mark on the surface of the fluororesin molded article subjected to the chemical etching treatment with ink mixed with a coloring material, and the step of printing the fluorine resin molded article having the identification mark printed thereon in an oxygen atmosphere. Heating in the step of decolorizing the surface portion of the chemically etched surface to which the identification mark is not attached, and heating the fluororesin molded body on which the identification mark is printed to remove the organic component contained in the coloring material. Removing, and laminating a sheet of substantially transparent resin on the surface of the fluororesin molded body to form a laminate, and heat-compressing and laminating the laminate with a mold to fuse. It is intended to provide a method for manufacturing a display body. That is, the present invention has the same effect as the above-described method, and also performs the decolorizing step and the organic component removing step in the optimal two-stage temperature ranges, respectively. Decolorization of the treated surface portion and removal of organic components contained in the identification display or carbonization are stably performed, and a clearer identification display body can be obtained.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
A production example of the identification display of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a main part showing a manufacturing process of an identification indicator according to an embodiment of the present invention, FIG. 2 is a plan view of a fluororesin molded body on which the identification indicator is printed, and FIG. FIG. 4 is a plan view of the sheet, FIG. 4 is a plan view of the identification display according to the embodiment of the present invention, and FIG. 5 is a view showing a state where the laminate is set in a mold.
[0012]
In FIG. 1A, a fluororesin molding 1a is a molding fired at a temperature equal to or higher than the melting point of the fluororesin. The shape of the fluororesin molding 1a is not particularly limited, and a sheet or film as shown in FIG. 1A is preferably used. When the fluororesin molding 1a is in the form of a sheet or a film, the thickness of the fluororesin molding 1a is not particularly limited, but is preferably 25 to 1000 μm, and particularly preferably 50 to 200 μm. The fluororesin sheet or film may be manufactured by a known method. For example, a sheet-shaped or film-shaped fluororesin film 1a is obtained by cutting from a fired cylindrical fluororesin molded body. Can be. PTFE is preferred as the fluororesin.
[0013]
Next, as shown in FIG. 1 (B), the surface of the fluororesin molded body 1a on which the identification mark is printed is subjected to a chemical etching treatment to form a chemical etching layer 7 having a thickness of about 10 μm on the surface. Obtain body 1b. The chemical etching treatment method is not particularly limited, and includes, for example, a treatment method using a solution obtained by dissolving metallic sodium in liquid ammonia. By this treatment, a carbonized chemical etching layer 7 is formed on the surface of the fluororesin molded body 1b, and the adhesion when ink is applied later is improved. On the other hand, the chemical etching layer 7 changes to brownish color and is identified. To make the readability of the image poor.
[0014]
Next, as shown in FIG. 1 (C), a predetermined identification mark 6 is printed on the surface of the fluororesin molded body 1b which has been subjected to the chemical etching treatment, using ink mixed with a coloring material. The identification display 6 is displayed according to the purpose of identification, and includes characters, symbols, numerical values, bar codes, or a combination thereof. Examples of a method for printing the identification display 6 include a thermal transfer method such as bar code printing, a screen printing method, a gravure printing method, a spin coating method, and a brush coating method. Thermal transfer is preferred. As the coloring material, any material may be used as long as it develops coloring on the surface of the fluororesin molded body. Specifically, the lightness, hue or reflectance between the color of the fluororesin molded body surface and the color of the coloring material is sufficient. Any material may be used as long as it is different, and examples thereof include inks and paints containing organic components such as pigments and waxes, resin components, and organic solvents. Normally, it is preferable to make the fluororesin sheet contain a light-colored filler, and to use a dark-colored coloring material for identification printed on the surface. Examples of the bright filler include titanium oxide, alumina, zinc oxide, boron nitride and the like. The melting point of wax or resin as an organic component is 40 to 110 ° C, and the decomposition or vaporization temperature is 130 to 320 ° C.
[0015]
Next, the fluororesin molded body 1b on which the identification mark 6 is printed is heated in an oxygen atmosphere to decolor the surface portion of the chemically etched surface not provided with the identification mark. The oxygen atmosphere may be usually an air atmosphere, and the heating temperature is in the range from the glass transition point of the fluororesin molded body to the melting point, and when PTFE is used as the fluororesin, the temperature is 127 ° C or more and less than 327 ° C. is there. The heating time is 1 to 20 hours. By this heat treatment, the chemical etching layer to which no identification is given is oxidized, and active carbon content in the chemical etching layer is removed as carbon dioxide gas. Therefore, the surface is decolorized and the identification display is sharpened. On the other hand, the chemical etching layer to which the identification mark is attached is protected by the carbon of the pigment included in the identification mark and is not oxidized by the heat treatment. Further, by the heat treatment, the organic component contained in the ink for identification display is melted, soaks into the chemical etching layer in the portion, and is removed by decomposition or vaporization, or is fixed by carbonization. On the other hand, the pigment contained in the ink for identification is attached or fixed to the surface of the chemical etching layer to stabilize the identification. When the heating temperature is lower than the glass transition point, the difference in the coefficient of thermal expansion between the chemical etching layer and the PTFE layer becomes small, and it becomes difficult to generate fine active pores of oxygen in the chemical etching layer. Takes a long time. On the other hand, if the heating temperature exceeds the melting point, the chemical etching layer is not only removed by vaporization, but also the chemical etching layer of the identification display portion is destroyed by the thermal decomposition of the organic component, which is not preferable.
[0016]
Further, in the method of the present invention, the step of heating the fluororesin molded body on which the identification mark is printed in an oxygen atmosphere to decolor the surface of the chemically etched surface to which the identification mark is not attached (hereinafter, referred to as “ The first heating step) is followed by a step of heating the fluororesin molded body on which the identification information is printed to remove the organic components contained in the coloring material (hereinafter, referred to as a “second heating step”). ) May be performed. The heating temperature in the first heating step is preferably in the range of not less than the glass transition point of the fluororesin molded body and less than the melting point thereof, and is preferably near the melting point or the pour point of the organic component of the ink. It is. The heating temperature of the second heating step is preferably in the range of not less than the glass transition point of the fluororesin molded body and less than the melting point, and near the temperature at which the organic component of the ink is decomposed. Specifically, the heating temperature is higher than the first heating temperature. Is higher than 150 ° C. in the high temperature range and lower than 327 ° C. By this two-step treatment, decolorization of the fluororesin molded body and removal of the organic components contained in the identification display are performed stably, and a clear and easy-to-disappear identification display body can be obtained.
[0017]
In the manufacturing method of the present invention, a substantially transparent resin sheet is laminated at least on the surface on which the identification mark is printed. As a lamination method, as shown in FIG. 5, a method of sandwiching the laminate in a mold, and heat-press-molding and fusing at a temperature equal to or higher than the melting point of the resin sheet and lower than the melting point of the fluororesin on which the identification mark is printed. Is preferred. The term “substantially transparent” means that it is only necessary to be transparent to the extent that the identification display using the coloring material can be identified from the outside. The substantially transparent resin sheet is not particularly limited. For example, a fluororesin sheet such as PFA, FEP or EPE, polyether sulfone (PES), polysulfone (PS), polyethylene terephthalate (PET), polyethylene (PE), polycarbonate (PC), polyphenylene oxide (PPO), and other resin sheets. Of these, a fluororesin sheet such as PFA, FEP, or EPE is preferable. Further, the thickness of the substantially transparent resin sheet is not particularly limited, but is preferably 0.5 to 2.0 mm, particularly preferably 0.7 to 2.0, from the viewpoints of chemical resistance and transparency. 1.5 mm is preferred.
[0018]
As a form of lamination of the substantially transparent resin sheet, at least the resin sheet may be laminated on the surface of the fluororesin on which the identification mark is printed. There is a form in which two resin sheets are used so as to cover them, and the peripheral edges thereof are heat-sealed and laminated so as to surround them. The resin sheet is a concept including a resin film.
[0019]
Next, the case where the transparent resin sheets 2a and 2b are PFA sheets will be described as an example. As shown in FIG. 1 (D), a PFA sheet 2a, 2b is laminated on the front and back surfaces of the fluororesin film 1 on which the identification mark is printed, and a laminate 10 is formed. Although the thickness of the PFA sheet is not particularly limited, it is preferably 0.5 to 2.0 mm, and particularly preferably 0.7 to 1.5 mm, from the viewpoint of chemical permeation resistance and transparency. Next, the laminate 10 is disposed between the molds 4 and 4 as shown in FIG.
[0020]
Next, heat compression molding is performed in the mold 4 at a temperature equal to or higher than the melting point of PFA and lower than the melting point of the fluororesin on which the identification mark is printed. The molding pressure is preferably 15 kgf / cm ² or more. If the molding pressure is low, the fusion of PFA may be incomplete. The molding time is preferably 5 minutes or more.
[0021]
Next, the heat-pressed molded body is cooled. The cooling method is not particularly limited, but a method of using a water-cooled cooling device or the like and rapidly cooling it at a cooling rate of, for example, 100 ° C./min or more is preferable. When such rapid cooling is performed, the crystallinity of PFA does not increase and the transparency increases. For this reason, when reading the identification display body, it is possible to read even if the thickness of the PFA is somewhat large.
[0022]
As shown in FIG. 1 (E), the identification indicator 11 obtained by the above-described method has a structure in which the printed fluororesin film 1 is wrapped around PFA sheets 2a and 2b. The sheets 2a and 2b are completely fused at the peripheral edge 5 thereof.
[0023]
INDUSTRIAL APPLICABILITY The identification indicator of the present invention is used for process management such as identification and sorting of articles in a production line such as a factory or the like for identification use of products in various industrial and logistics fields, and particularly for process management in a semiconductor manufacturing line. Suitable for use. Therefore, the shape of the identification indicator is not particularly limited, and may be a sheet shape, a film shape, or the like.
[0024]
【Example】
Next, the present invention will be described more specifically with reference to examples.
Example 1
A fired 200 μm thick PTFE sheet containing a trace amount of a bright-colored filler, titanium oxide, was subjected to a chemical etching treatment with a solution in which liquid ammonium was dissolved. By this treatment, the PTFE sheet turned brown. Next, using a barcode printer and a thermal transfer ribbon B110C (manufactured by Tohoku Ricoh Co., Ltd.), a miniaturized barcode was printed on the chemically etched surface of the PTFE. This printing had good ink riding and no defect in the identification display was observed. Next, the PTFE film on which the identification was printed was subjected to a heat treatment at 250 ° C. for 5 hours to remove the chemical etching layer to which the identification was not attached and decolorized. Next, heat treatment was performed at 300 ° C. for 1 hour to remove organic components of the ink. Next, as shown in FIG. 5, a PTFE sheet on which a bar code is printed and a PFA sheet having a thickness of about 1,000 μm are laminated, inserted into a mold, and subjected to a surface pressure of about 20 kgf / cm ² and a temperature of about 320 ° C. Heat compression molding was performed for 7 minutes. Next, cooling was performed to 25 ° C at a cooling rate of 100 to 150 ° C / min using a water-cooled cooling device. Thereafter, the molded product was taken out of the mold to obtain a PTFE identification indicator.
[0025]
Example 2
Example 1 Example 1 was repeated except that the PTFE film on which the identification information was printed in the same manner as in Example 1 was subjected to one-stage heat treatment at 250 ° C. for 3 hours to simultaneously remove the PTFE color and remove the organic components of the identification information. In the same manner as in the above, a PTFE identification indicator was obtained.
[0026]
Comparative Example 1
The procedure was performed in the same manner as in Example 1, except that the heat treatment was not performed on the PTFE film on which the identification information was printed.
[0027]
The bar code readability of each of the PTFE identification bodies of the examples and the comparative examples was evaluated. The barcode readability was evaluated by reading the number of the identification display bodies 100 using a barcode reader and reading the number at one time. As a result, 100 out of 100 PTFE identification bodies of Example 1 and Example 2 could be read. In the comparative example, 100 out of 100 readings could not be performed.
[0028]
【The invention's effect】
According to the production method of the present invention, the surface of the fluororesin molded body is activated by the chemical etching treatment, and fine printing with ink is possible. Therefore, for example, a complicated identification display such as a two-dimensional barcode can be performed. Further, discoloration due to the chemical etching process is decolorized by the heat treatment, and the readability of the identification display body is improved. In addition, since the organic components of the ink are removed simultaneously with the decolorization, the pigment of the ink strongly adheres to the etching layer, thereby stabilizing the identification display. Further, since the transparency of the transparent resin sheet is increased by rapid cooling after the laminating and fusing steps, the thickness of the resin sheet can be increased without impairing the readability by a barcode reader. For this reason, chemical resistance is improved and, for example, it can be preferably used in a semiconductor manufacturing line.
[Brief description of the drawings]
FIG. 1 is a fragmentary cross-sectional view showing a process of manufacturing an identification display according to an embodiment of the present invention.
FIG. 2 is a plan view of a PEEK molded body on which an identification mark is printed.
FIG. 3 is a plan view of a transparent resin sheet.
FIG. 4 is a plan view of the identification display according to the embodiment of the present invention.
FIG. 5 is a view showing a state in which the laminate is set in a mold.
[Explanation of symbols]
1a Fluororesin molded body 1b Fluororesin molded body 2a, 2b, 2c subjected to chemical etching Transparent resin sheet 4 Mold 5 Fused part 6 Identification 7 Chemical etching layer 10 Laminate 11 Identification identification

Claims (5)

On the surface of the fluororesin molded body that has been subjected to the chemical etching treatment, a step of printing a predetermined identification mark with ink mixed with a coloring material,
The fluororesin molded body on which the identification is printed is heated in an oxygen atmosphere at a temperature equal to or higher than the glass transition point of the fluororesin molded body and lower than the melting point, and the chemically etched surface portion without the identification is given. A process of decolorization,
A step of laminating a sheet of substantially transparent resin on the surface of the fluororesin molded body to form a laminated body, and heat-compressing and molding the laminated body with a mold to fuse.
A method for producing an identification display, comprising: On the surface of the fluororesin molded body that has been subjected to the chemical etching treatment, a step of printing a predetermined identification mark with ink mixed with a coloring material,
The fluororesin molded body on which the identification is printed is heated in an oxygen atmosphere at a temperature equal to or higher than the glass transition point of the fluororesin molded body and lower than the melting point, and the chemically etched surface portion without the identification is given. A process of decolorization,
Heating the fluororesin molded body on which the identification display is printed, and removing an organic component contained in the coloring material;
A step of laminating a sheet of substantially transparent resin on the surface of the fluororesin molded body to form a laminated body, and heat-compressing and molding the laminated body with a mold to fuse.
A method for producing an identification display, comprising: 3. The method according to claim 1, wherein the fluororesin molded body is baked at a temperature equal to or higher than a melting point of the fluororesin molded body before performing the chemical etching treatment. Law. The method for producing an identification display according to any one of claims 1 to 3 , wherein the fluororesin is polytetrafluoroethylene. The method for producing an identification display according to any one of claims 1 to 4 , wherein the fluororesin molded body contains a light-colored filler.

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