Self-fusing tape and method for manufacturing the same

Abstract

To provide a colored self-fusing tape which has self-fusing property and is made of fluorine resin having self-fusing property, and a method for manufacturing a colored self-fusing tape.SOLUTION: A self-fusing tape is provided, including a porous film made of fluorine resin, and a coloring agent on the porous film. An abundance of a fluorine element on the surface of the self-fusing tape is 50 at% or more. A method for manufacturing the self-fusing tape is also provided. The manufacturing method includes: obtaining a fluorine resin film or a fluorine resin sheet; performing uniaxial drawing on the fluorine resin film or the fluorine resin sheet, thereby obtaining a porous film made of fluorine resin; coloring the porous fluorine resin film using a coloring agent, thereby obtaining a colored porous film; and performing rolling processing on the colored porous film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a self-fusing tape and a method for manufacturing the self-fusing tape. [Background technology]

[0002] Fluororesins have the properties of being both heat-resistant and non-sticky. Furthermore, porous fluororesin membranes can be both waterproof and breathable. The properties of fluororesins are utilized in a variety of applications, including thin fluororesin products and components such as sheet materials and films, as well as fluororesin products and components with three-dimensional structures. For example, fluororesin tape can be used as an insulating tape for bundling electric wires or as a waterproof sealing tape for pipes. Another example of an application for porous fluororesin membranes is a waterproof sound-permeable membrane.

[0003] For example, Patent Document 1 (JP 2009-43483 A) describes a bundling tape using a porous membrane of tetrafluoroethylene resin (polytetrafluoroethylene; PTFE). In this bundling tape, the PTFE porous membrane itself has self-adhesive properties and does not have an adhesive layer. According to Patent Document 1, the high non-adhesive properties of PTFE limit the types of adhesives that can be used. As a result, while general PTFE adhesive tapes have high adhesive strength, they have poor releasability, which makes them difficult to use for temporarily fastening cables or to rewind. For this reason, Patent Document 1 provides a porous membrane with self-adhesive properties instead of using an adhesive.

[0004] Fluoroplastics such as tetrafluoroethylene resin are white. The white color can impair the appearance of products or locations where fluoroplastic components are used. For this reason, colored sealing tapes and porous films have been developed to enhance their design.

[0005] For example, Patent Document 2 (JP 2004-263849 A) ​​describes a pipe sealing tape that has a color that matches the finished color of the pipe. Although there is no mention of a specific material, this pipe sealing tape solves the drawback of sealing tapes being limited to specific colors such as white, which impairs the appearance of the pipe.

[0006] Patent Document 3 (JP Patent Publication No. 7-289865) describes a waterproof and breathable filter made of a colored expanded porous polytetrafluoroethylene membrane. According to Patent Document 3, PTFE made porous by expansion has the characteristic appearance of being pure white. This not only limits design freedom in terms of color, but also arouses user curiosity, leading to accidents such as the white filter being poked with a sharp tip of a writing implement or the like, resulting in the loss of waterproofness. As a specific example, Patent Document 3 uses a gray-colored expanded porous PTFE membrane as the vent filter of a black mobile phone, and a pink-colored expanded porous PTFE membrane as the vent filter of a red mobile phone, thereby reducing visual discomfort.

[0007] Patent Document 4 (JP 2011-52180 A) describes a black PTFE porous membrane that is dyed black and has low achromatic brightness, as well as a ventilation membrane and ventilation member using the same. According to Patent Document 4, even if the membrane is colored to prevent damage caused by curious users pricking it, as in Patent Document 3, the color may fade due to exposure to high-temperature atmospheres or sunlight or other light. The black PTFE porous membrane described in Patent Document 4 uses a large amount of dye to reduce brightness. Therefore, even if the dye near the surface fades due to light or heat, the absolute amount of dye that remains unfaded underneath is large, thereby suppressing overall color fading.

[0008] Patent Document 5 (JP-A-8-27304) describes a porous fluororesin body whose surface is coated with a colorant and a water-repellent agent. This porous fluororesin body is colored yet has both breathability and water-repellency, and can be used, for example, as a closing material for air vents in telephones and mobile communication devices of various colors that match the device body color. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-43483 [Patent Document 2] Patent Application No. 2004-263849 [Patent Document 3] Japanese Patent Application Publication No. 7-289865 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-52180 [Patent Document 5] Japanese Patent Application Publication No. 8-27304 Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide a colored self-adhesive tape made of fluororesin and having self-adhesive properties, and a method for producing the same. [Means for solving the problem]

[0011] According to an embodiment of the present invention, Polytetrafluoroethylene resin The self-fusing tape includes a porous film made of the material and a colorant on the porous film. Determined by energy dispersive X-ray spectroscopy The abundance of fluorine element is 51.3 at% or more. The colorant is Ecobeute dye ink manufactured by Almark.

[0012] According to another embodiment of the present invention, there is provided a method for manufacturing a self-fusing tape, the method comprising the steps of: Polytetrafluoroethylene resin Film or Polytetrafluoroethylene resin Obtaining a seat; Polytetrafluoroethylene resin The method includes obtaining a porous film made of a porous material, obtaining a colored porous film, and subjecting the colored porous film to a rolling treatment. Polytetrafluoroethylene resin Film or Polytetrafluoroethylene resin The colored porous film is obtained by stretching the sheet. Almark Ecobeute dye ink This can be achieved by coloring using The rolling treatment is carried out under conditions such that the abundance ratio of elemental fluorine on the surface after rolling, as determined by energy dispersive X-ray spectroscopy, is 51.3 at % or more. [Effects of the Invention]

[0013] According to the above-mentioned configuration, it is possible to provide a self-fusing tape that has the properties of a fluororesin, is colored to provide excellent designability, and has self-fusing properties to provide excellent winding workability. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view schematically illustrating an example of a self-fusing tape according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Porous tapes made from fluororesin such as polytetrafluoroethylene (PTFE) are usually white. Therefore, depending on the product, using fluororesin porous tape can detract from the design. In addition, depending on where the fluororesin porous tape is used, it may arouse the user's curiosity. Therefore, there is a high possibility that the tape membrane or parts will be damaged if the user pokes it.

[0016] Possible methods for coloring to enhance design include coloring the raw materials or coloring after molding. However, the former raises concerns about contamination of the equipment and work area used in tape manufacturing. Furthermore, when the material is stretched to make it porous, which gives it the flexibility required for use as a tape, the distribution of the colorant (the density of the pigment) becomes sparse, resulting in a faded color. The latter reduces self-adhesion, i.e., the tape's ability to adhere to itself. Poor self-adhesion can cause the tape's lapped portion to slip, reducing the efficiency of winding it onto the substrate and increasing the likelihood of the tape coming undone during use.

[0017] The following describes embodiments of the present invention. While the description will be made with reference to drawings, these drawings are schematic diagrams intended to facilitate the explanation and understanding of the embodiments, and the shapes, dimensions, ratios, etc. may differ from those of the actual device. These may be modified as appropriate in consideration of the following description and known technologies.

[0018] <Self-fusing tape> The self-fusing tape according to the embodiment includes a porous film made of a fluororesin and a colorant on the porous film, and the abundance ratio of elemental fluorine on the surface of the tape is 50 at % or more.

[0019] Such self-fusing tape is colored with a coloring agent and can be colored in a color other than the white inherent in the fluororesin material itself. For example, by using a tape colored in a color that easily blends in with a dark background, such as black or a dark color, it can be made less noticeable to the user. In addition, the color can be selected to suit the location where the tape will be used, taking into consideration the design.

[0020] This self-fusing tape can exhibit self-fusing properties even when colored in this way. Although a colorant is present on the porous fluororesin film contained in the self-fusing tape, the entire surface of the film is not covered with the colorant. The porous fluororesin film is partially exposed on the surface of the main side of the self-fusing tape, and specifically, the abundance ratio of fluorine atoms on the surface of the main side of the tape is 50 at% or more. By exposing the fluororesin on the surface of the tape, the self-fusing properties of the fluororesin are exhibited.

[0021] The constituent molecules of fluororesin contain long-chain molecules. When the surfaces of fluororesin members are pressed together, the long-chain molecules on each surface become entangled. This is how fluororesin exhibits self-bonding properties. However, when fluororesin is baked, the arrangement of the constituent molecules becomes uniform and the long-chain molecules no longer become entangled, thereby impairing the self-bonding properties. For this reason, it is desirable to use unbaked fluororesin for porous tape.

[0022] Since the porous film is made of fluororesin, the self-fusing tape can have the properties of fluororesin, such as heat resistance and waterproofness. As the fluororesin, polytetrafluoroethylene (PTFE) is preferred.

[0023] The self-fusing tape can be used in a variety of applications, such as an insulating tape for bundling electric wires and a waterproof sealing tape for pipes, etc. However, the use of the self-fusing tape is not limited to these examples.

[0024] The colorant may be, for example, a coloring material containing a dye, a pigment, an inorganic substance, a metal, or an organic substance. The colorant preferably contains an organic solvent as a solvent. Note that the colorant used should not contain a fluorine element.

[0025] The width of the self-fusing tape in the transverse direction (TD) can be, for example, 10 mm or more and 200 mm or less. The width in the TD direction is preferably 10 mm or more and 50 mm or less, and more preferably 10 mm or more and 25 mm or less. Self-fusing tapes with widths within this range have good handleability. Note that the transverse direction (TD) here refers to the direction perpendicular to the machine direction (MD), which is parallel to the unwinding direction of a wound self-fusing tape such as a tape roll. In a typical example, the transverse direction (TD) refers to the direction of the short side of a strip-shaped self-fusing tape.

[0026] The thickness of the self-fusing tape is preferably between 10 μm and 260 μm. If the thickness is within this range, the tape can be easily unwound and wrapped around an object, making it easy to handle.

[0027] Next, specific examples of the self-fusing tape according to the embodiment will be described with reference to the drawings. Figure 1 shows a schematic diagram of one example of the self-fusing tape according to the embodiment.

[0028] 1 is a perspective view schematically illustrating an example of a self-fusing tape according to an embodiment. The illustrated tape roll 10 includes a self-fusing tape 1 and a winding core 2.

[0029] The self-fusing tape 1 has a strip shape with its long sides aligned with the unwinding direction 100 of the tape roll 10. The self-fusing tape 1 is a porous film made of fluororesin colored with a colorant. The colorant is present on the outer surface of the porous film and within the pores. Because FIG. 1 itself is a black and white drawing, the self-fusing tape 1 is shown in white, but actual self-fusing tapes are colored, for example, black or gray, and are not white. The color of the self-fusing tape is not limited to black or gray.

[0030] The winding core 2 may have, for example, a cylindrical shape. As the winding core 2, for example, a winding core generally used for tape rolls, such as a paper winding core, may be used. The shape of the winding core 2 is not limited to that shown in the figure, and may be, for example, a reel shape. The self-fusing tape 1 is wound around the cylindrical outer periphery of the winding core 2.

[0031] <Manufacturing method> An example of a method for producing the self-fusing tape according to the above embodiment will now be described in detail.

[0032] The method for manufacturing a self-fusing tape according to the embodiment includes obtaining a fluororesin film or a fluororesin sheet, obtaining a fluororesin porous film, obtaining a colored porous film, and rolling the colored porous film. The fluororesin porous film is obtained by stretching the fluororesin film or the fluororesin sheet. The colored porous film is obtained by coloring the porous film with a colorant.

[0033] That is, the outline of the manufacturing method is as follows: First, a fluororesin film or sheet is obtained. The fluororesin film or fluororesin sheet is stretched to obtain a porous fluororesin film. The obtained porous film is colored using a colorant. After coloring, the film is rolled. After the rolling, the film is cut as necessary to adjust the tape dimensions.

[0034] Fluororesin films and sheets can be obtained by, for example, extrusion molding. For example, a mixture containing PTFE raw material powder and an extrusion aid, or a preform (billet) obtained by compressing the mixture, can be extruded into a sheet to obtain a PTFE film or sheet.

[0035] The raw material powder may be, for example, a fine powder of PTFE. The fine powder is made of minute PTFE particles and is obtained by coagulating and drying an aqueous dispersion obtained by emulsion polymerization.

[0036] The resulting film or sheet is stretched to obtain a porous fluororesin film. Stretching a fluororesin film to make it porous allows for a flexible film to be obtained. Furthermore, porous films do not repel colorants, allowing for coloring. For stretching, for example, uniaxial stretching is performed. For example, stretching using a heated roll or stretching in a heated atmosphere can be performed. Film strength can be improved by heating below the melting point of the fluororesin. Since excessively high heating temperatures can reduce self-bonding properties, heating below 300°C is desirable. Furthermore, when an extrusion aid is used, the extrusion aid can be dried by stretching while heating. Alternatively, the extrusion aid may be dried prior to the stretching process. Typical extrusion aids volatilize at approximately 100°C to 300°C. Since baking of the fluororesin would impair self-bonding properties, baking is not performed.

[0037] The obtained porous film is colored using a colorant to obtain a colored porous film. The colorant is applied to the surface of the porous film. Methods for applying the colorant include, for example, dipping and sputtering. The colorant penetrates into some of the pores of the porous film, thereby coloring the film.

[0038] After coloring, the film is rolled. The roll-pressing can be performed, for example, by passing the colored porous film between a pair of roll presses. The treatment may be performed while heating. The heating temperature is set to the melting point of the fluororesin or lower.

[0039] By performing the rolling treatment, a portion of the porous film that was covered with the colorant is exposed. The rolling can force a portion of the colorant that covered the surface of the porous film into the pores of the porous film. Furthermore, because the porous film stretches in the planar direction, the colorant on the film surface is dispersed so that its distribution is broadened. By exposing the porous film through the rolling treatment so that the fluorine content on the surface is 50 at% or more, a colored porous film is obtained in which the self-bonding properties that were lost when the film was covered with the colorant are restored. The rolling treatment is performed under conditions such that the fluorine content on the surface is 50 at% or more, and is adjusted appropriately depending on the amount of colorant, etc.

[0040] The colored porous film after the rolling treatment is wound onto a roll to obtain a log roll, which is a precursor to the tape roll. From the log roll state, the film is cut so that the tape width when unwound is the desired width, thereby obtaining a roll of self-fusing tape. The film can be cut, for example, by performing a pressure cutting process or a slitting process on the log roll.

[0041] As described above, it is possible to produce a colored self-adhesive tape made of PTFE that exhibits self-adhesive properties.

[0042] <Measurement method> Various measurement methods for self-fusing tape are described below. Specifically, we will explain how to measure the constituent materials of the tape, how to measure the proportion of fluororesin on the tape surface by elemental analysis, and how to confirm whether the tape has self-fusing properties.

[0043] (Tape material measurement) The resin material constituting the tape can be identified as follows.

[0044] It is possible to confirm that the resin material is a fluororesin by measuring the melting point using a differential scanning calorimeter (DSC).

[0045] (Elemental analysis) The proportion of fluorine element present on the surface of the porous tape can be determined by performing elemental analysis using energy dispersive X-ray spectroscopy (EDX) to determine the proportion of fluorine resin exposed on the surface of the porous tape.

[0046] (Confirmation of self-bonding properties) Whether or not a porous tape has self-bonding properties can be confirmed as follows.

[0047] Prepare two tape test pieces. For example, prepare tape test pieces with dimensions of approximately 10 cm x 1 cm each. Place the two test pieces on top of each other and press 5 cm from the edge of the overlapping part. The pressing pressure should be 0.2 MPa. After pressing, pull up the test piece on top. If the lower test piece is also pulled up when the upper test piece is pulled up, it is determined that there is self-adhesion. If the lower test piece cannot be pulled up, it is determined that the two test pieces did not stick together and there is no self-adhesion.

[0048] [Example] <Manufacturing> (Comparative Example 1) A PTFE porous tape was manufactured as follows. PTFE fine powder was used as a raw material and a PTFE sheet was obtained by extrusion molding. The obtained PTFE sheet was subjected to uniaxial stretching to perform a porous treatment, thereby obtaining a porous PTFE sheet. The obtained porous PTFE sheet was cut into a strip shape to obtain a porous tape.

[0049] (Comparative Example 2) A colored porous tape made of PTFE was manufactured as follows. The same procedure as in Comparative Example 1 was followed up to uniaxial stretching of the PTFE sheet. The obtained porous PTFE sheet was colored by a dipping method and then cut into a strip shape to obtain a colored porous tape. As the colorant, a colored coating solution obtained by dissolving Ecobeute Ink Black (manufactured by Alumack Co., Ltd.) in ethanol at a concentration of 50% by weight was used.

[0050] Example 1 A colored porous tape made of PTFE was produced as follows. The same procedure as in Comparative Example 2 was used to color a porous PTFE sheet, which was then rolled and cut into a strip shape to obtain a colored porous tape. The rolling was performed under conditions such that the element abundance ratios determined by elemental analysis on the surface of the rolled tape were the values ​​shown in Table 1 below.

[0051] Example 2 A colored porous tape made of PTFE was produced in the same manner as in Example 1, except that the conditions of the rolling treatment were changed so that the element abundance ratios were the values ​​shown in the following Table 1. Specifically, rolling was performed with a thinner thickness after rolling than in Example 1.

[0052] Example 3 A colored porous tape made of PTFE was produced as follows. The porous PTFE sheet was colored in the same manner as in Comparative Example 2, except that the concentration of the colorant was changed to 30% by weight. The porous PTFE sheet was then rolled and cut into a strip shape to obtain a colored porous tape. The rolling was carried out under the same conditions as in Example 2.

[0053] <Evaluation> Each of the obtained porous tapes was subjected to elemental analysis by the method described above, and also evaluated by the method described above to determine whether each porous tape had self-bonding properties.

[0054] Table 1 below summarizes the manufacturing conditions, external color, elemental analysis results, and whether or not the tapes in Comparative Examples 1 and 2, and Comparative Examples 1-3 have self-adhesive properties. The manufacturing conditions indicate whether or not coloring was performed using a colorant, and whether or not the tape was rolled after coloring. The tape color indicates a color that can be visually confirmed. The elemental analysis results indicate the respective abundance ratios of fluorine (F), carbon (C), and oxygen (O) on the tape surface. Regarding self-adhesive properties, the table indicates whether or not the self-adhesive properties were determined to exist using the above method.

[0055] [Table 1]

[0056] The tape produced in Comparative Example 1 exhibited self-adhesive properties, but was not colored, and therefore had a white color derived from the PTFE fine powder raw material, and lacked design. The tape produced in Comparative Example 2 was black, but did not exhibit self-adhesive properties, and workability was poor. The tapes produced in Examples 1 to 3 were all black or gray, and also exhibited self-adhesive properties, and were excellent in design and workability at the same time.

[0057] A comparison between Comparative Example 2 and Examples 1 to 3 reveals that when the proportion of fluorine elements on the tape surface is less than 50 at.%, the adhesive properties are impaired, and that even if the tape surface is partially covered with a colorant, the adhesive properties can be exhibited as long as the proportion of fluorine elements is 50 at.% or more.

[0058] The self-fusing tape according to one or more of the embodiments and examples described above includes a porous film made of fluororesin and a colorant. The colorant is present on the porous film, such as on the inner wall surfaces of the pores of the porous film or on the main surface. Fluorine elements are present at a concentration of 50 at% or more on the surface of the self-fusing tape. This self-fusing tape has the properties of fluororesin, and is colored to provide excellent design, and its self-fusing properties make it easy to wind.

[0059] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. The inventions described in the original claims of this application are set forth below. [1] A porous film made of fluororesin; a colorant on the porous film, A self-fusing tape having a surface containing fluorine atoms at a concentration of 50 at % or more. [2] The self-fusing tape according to [1], wherein the fluororesin contains tetrafluoroethylene resin. [3] Obtaining a fluororesin film or a fluororesin sheet; Obtaining a porous film made of fluororesin by performing a stretching treatment on the fluororesin film or the fluororesin sheet; coloring the porous film with a colorant to obtain a colored porous film; subjecting the colored porous film to a rolling treatment; A method for producing a self-fusing tape, comprising: [Explanation of symbols]

[0060] 1...self-fusing tape, 2...core, 10...tape roll, 100...unwinding direction.

Claims

1. A porous film made of tetrafluoroethylene resin, a colorant on the porous film, The abundance ratio of elemental fluorine on the surface determined by energy dispersive X-ray spectroscopy is 51.3 at% or more, The colorant is Ecobeute dye ink manufactured by Alumak Co., Ltd., a self-fusing tape.

2. A self-fusing tape as described in claim 1, wherein the abundance ratio of the fluorine element is 57.98 at% or less.

3. Obtaining a tetrafluoroethylene resin film or a tetrafluoroethylene resin sheet; obtaining a porous film made of tetrafluoroethylene resin by performing a stretching treatment on the tetrafluoroethylene resin film or the tetrafluoroethylene resin sheet; coloring the porous film using Ecobeute dye ink manufactured by Almark Co., Ltd. to obtain a colored porous film; rolling the colored porous film under conditions such that the abundance ratio of fluorine element determined by energy dispersive X-ray spectroscopy on the surface after rolling is 51.3 at% or more; A method for producing a self-fusing tape, comprising:

4. A method for manufacturing a self-fusing tape as described in claim 3, wherein the rolling process is carried out under conditions such that the abundance ratio of the fluorine element is 57.98 at% or less.

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