Adhesive tape

Abstract

To provide an adhesive tape that is completely free from problems of abrasion and peeling of a printing layer, limitation on ink to be used for the printing layer, and the problem of detachment of the printing layer, and that uses a paper substrate gentle to the environment.SOLUTION: An adhesive tape comprises a first substrate, a second substrate, an adhesive layer and a printing layer. The printing layer is disposed between the first substrate and the second substrate. The adhesive layer is disposed on a side where the printing layer of the first substrate is not present. The first substrate and the second substrate are composed of a glassine paper, or the first substrate is composed of a transparent plastic, and the second substrate is composed of a glassine paper. The adhesive tape is advantageously used for binding of vegetables or fresh flowers, sealing of container packaging or a packaging bag for food, or identifiable display of commodities.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an adhesive tape that uses environmentally friendly paper as a base material, has no problems with wear or peeling of the printing layer, and has no restrictions on the ink used for the printing layer. In particular, it relates to an adhesive tape suitable for use in tying vegetables or fresh flowers, or sealing food containers or packaging bags, or identifying products.

Background Art

[0002] Conventionally, adhesive tapes have been used for tying vegetables or fresh flowers, or sealing food containers or packaging bags, or identifying products. Such adhesive tapes include those having a printing layer printed with characters, symbols, patterns, etc. representing the names of vegetable and fresh flower shippers, brand names, store names, barcodes, QR codes (registered trademarks), etc. with ink, and have been conventionally used (see, for example, Patent Documents 1 and 2). Such adhesive tapes generally have a base material, an adhesive layer, and a printing layer, and paper or a plastic film is used as the constituent material of the base material. The problems of such conventional adhesive tapes will be described below while referring to FIGS. 1 and 2.

[0003] Figure 1 shows an example of a conventional adhesive tape in which an adhesive layer and a printed layer are arranged on each side of the base material. This type of adhesive tape generally uses paper as the base material, but because the printed layer is exposed on the surface of the adhesive tape, if it is used to bundle vegetables such as green onions, for example, when adjacent vegetables come into contact and rub against each other during display in stores, the letters, symbols, and patterns on the printed layer will wear away and become fainter, making it difficult for consumers to read information such as the name of the shipper or brand name shown on the printed layer. In cases of excessive friction, the printed layer may peel off, making it impossible for consumers to read this information at all. Furthermore, this type of adhesive tape is intended for use in applications that may come into contact with food, but there is a problem in that only inks compliant with the Food Sanitation Law can be used for the printed layer that may come into direct contact with food. Furthermore, since this type of adhesive tape is generally sold in a wound roll form, a release layer is formed on top of the printed layer to facilitate dispensing during use. However, when the release agent for this release layer is applied, the ink in the printed layer may dissolve, potentially causing the printed layer to peel off when the adhesive tape is dispensed.

[0004] To overcome the problems of the type of adhesive tape shown in Figure 1, the type of adhesive tape shown in Figure 2 has been proposed. Figure 2 shows an example of a conventional adhesive tape in which a printed layer is placed between the adhesive layer and the substrate. This type of adhesive tape commonly uses transparent plastic as the constituent material of the substrate, but unlike the type shown in Figure 1, the printed layer is not exposed on the surface of the adhesive tape and is covered by the substrate, so the drawbacks and problems of the type shown in Figure 1 do not occur. However, in the case of the type shown in Figure 2, since the printed layer is in direct contact with the adhesive layer, if the adhesion between the adhesive and the adherend is higher than the adhesion between the substrate and the printed layer, there is a problem of the printed layer detaching from the substrate when the tape is peeled off, and remaining on the adherend side together with the adhesive layer. In addition, this type of adhesive tape has the problem of being unenvironmentally unfriendly because it uses plastic as the substrate. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 56-26968 [Patent Document 2] Japanese Patent Publication No. 2016-35071 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention was devised to solve the problems of the prior art described above, and its purpose is to provide an adhesive tape that does not have problems with wear or peeling of the printed layer, has no restrictions on the ink used for the printed layer, does not have problems with the printed layer detaching, and uses an environmentally friendly paper substrate. [Means for solving the problem]

[0007] The inventors, through diligent research to achieve the above objectives, have discovered that in an adhesive tape having a paper substrate as shown in Figure 1, by placing another transparent substrate on the side where the paper substrate of the printed layer does not exist, and covering the surface of the printed layer with another transparent substrate, it is possible to maintain the visibility of the printed layer while avoiding problems of wear and peeling of the printed layer and limitations on the ink used for the printed layer. Furthermore, by using highly transparent "glassine paper" instead of transparent plastic as this other transparent substrate, environmental issues can also be considered. In particular, unlike ordinary paper such as crepe paper and Japanese paper that are commonly used as paper substrates for adhesive tapes, "glassine paper" does not contain a sealing resin, making it more recyclable and environmentally friendly than ordinary paper. In addition, because "glassine paper" does not contain a sealing resin, it has high heat resistance and is less prone to thermal shrinkage, making it suitable for pitch printing where the same design is printed repeatedly. Moreover, "glassine paper" is processed under high pressure during manufacturing, resulting in superior smoothness compared to ordinary paper, and thus superior adhesion between adjacent layers.

[0008] This invention was completed based on the above findings, and the following (1) to ( 3 It has the following configuration: (1) In an adhesive tape comprising a first substrate, a second substrate, an adhesive layer, and a printed layer, the printed layer is positioned between the first substrate and the second substrate, and the adhesive layer is positioned on the side of the first substrate where the printed layer does not exist. , the The first and second base materials are made of glassine paper. , and adhesive tape being used to tie up vegetables or fresh flowers, or to seal food containers or packaging bags. Adhesive tape characterized by [this feature]. ( 2 (1) A primer layer is placed between the adhesive layer and the first substrate, an adhesive layer is placed between the printing layer and the second substrate, and a release agent layer is placed on the side of the second substrate where the adhesive layer does not exist. ) The adhesive tape described. ( 3 (1) A primer layer is placed between the adhesive layer and the first substrate, an adhesive layer is placed between the first substrate and the printing layer, and a release agent layer is placed on the side of the second substrate where the printing layer does not exist. ) The adhesive tape described. [Effects of the Invention]

[0009] The adhesive tape of the present invention covers the surface of the printed layer with highly transparent "glassine paper," thus maintaining the visibility of the printed layer while avoiding problems with wear and peeling of the printed layer and limitations on the ink used for the printed layer. Furthermore, unlike ordinary papers such as crepe paper and Japanese paper, "glassine paper" does not contain sealing resin, making it more recyclable and environmentally friendly than these papers. In addition, because the adhesive tape of the present invention uses "glassine paper" which has high heat resistance and is less prone to heat shrinkage, it is suitable for pitch printing where the same design is printed repeatedly. Moreover, because the adhesive tape of the present invention uses "glassine paper" which is smoother than ordinary paper, it has excellent adhesion to adjacent layers. [Brief explanation of the drawing]

[0010] [Figure 1]Figure 1 shows a schematic diagram of an example of the layer structure of a conventional adhesive tape. [Figure 2] Figure 2 shows a schematic diagram of another example of the layer structure of a conventional adhesive tape. [Figure 3] Figure 3 shows a schematic diagram of an example of the layer structure of the adhesive tape of the present invention. [Figure 4] Figure 4 shows a schematic diagram of another example of the layer structure of the adhesive tape of the present invention. [Figure 5] Figure 5 shows a schematic diagram of an example of the manufacturing procedure for the adhesive tape of the present invention. [Figure 6] Figure 6 shows an example of the use of the adhesive tape of the present invention. [Modes for carrying out the invention]

[0011] The adhesive tapes of the present invention will be described below with reference to the drawings, but the present invention is not limited to these. Note that the drawings are schematic for illustrative purposes, and therefore the ratios of the thicknesses of each layer may differ from the actual ones.

[0012] The adhesive tape of the present invention comprises two base materials, an adhesive layer, and a printed layer as basic constituent layers, and is suitably used for purposes such as bundling vegetables such as spinach or fresh flowers such as chrysanthemums, sealing containers or packaging bags of food products such as prepared foods, identifying purchased goods for the purpose of preventing shoplifting, or identifying goods for the purpose of detecting when they have been opened.

[0013] An example of the layer structure of the adhesive tape of the present invention is shown in FIG. 3. The adhesive tape in FIG. 3 has a basic structure in which a printing layer is disposed between a first base material and a second base material, and an adhesive layer is disposed on the side where the printing layer of the first base material does not exist. In the adhesive tape of FIG. 3, further, if necessary, a primer layer can be disposed between the adhesive layer and the first base material, an adhesive layer can be disposed between the printing layer and the second base material, and a release agent layer can be disposed on the second base material. Combining these, the adhesive tape of the present invention has a basic structure in which an adhesive layer, a first base material, a printing layer, and a second base material are disposed in order from the side intended to face the adherend. If necessary, a primer layer is disposed between the adhesive layer and the first base material, an adhesive layer is disposed between the printing layer and the second base material, and a release agent layer is disposed on the side of the second base material where the adhesive layer does not exist.

[0014] In the present invention, the adhesive layer is provided for adhesion of the adhesive tape to the adherend. As the constituent material of the adhesive layer, for example, conventionally known adhesives such as acrylic adhesives, rubber adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives can be used. It is preferable to select an adhesive layer having sufficient adhesive force for adhesion of the adhesive tape to the adherend. Further, it is preferable to select an adhesive layer that does not leave glue residue when peeled off and has sufficient adhesive force for re-adhesion if necessary. Specifically, the adhesive force of the adhesive layer is, for example, 0.5 to 6.0 N / 10 mm, preferably 1.0 to 5.0 N / 10 mm at the first adhesion, and, for example, 0.3 to 5.0 N / 10 mm, preferably 0.5 to 4.0 N / 10 mm at re-adhesion. The thickness of the adhesive layer is, for example, 2 to 70 μm, preferably 10 to 50 μm.

[0015] In the present invention, the first base material serves as a support of the adhesive tape. Further, the first base material is disposed between the adhesive layer and the printing layer so that the printing layer does not directly contact the adhesive layer, and also has a role of preventing the problem of detachment of the printing layer.

[0016] In the present invention, the first substrate is preferably composed of glassine paper in terms of recyclability, but can also be composed of a transparent plastic. Glassine paper is a high-density paper manufactured by using sulfite pulp that has been finely beaten for a long time as a raw material and performing high-pressure processing using a smooth roller called a supercalender. Different from ordinary papers such as crepe paper and Japanese paper that are conventionally commonly used as the paper substrate of adhesive tapes, glassine paper does not contain a blocking resin, so it is more recyclable than ordinary paper and is more environmentally friendly. In addition, since glassine paper does not contain a blocking resin, it has high heat resistance and is difficult to thermally shrink. Therefore, it is also suitable for forming a printing layer by pitch printing in which the same design is repeatedly printed. Furthermore, glassine paper is subjected to high-pressure processing during manufacture, and is excellent in smoothness and transparency compared to ordinary paper.

[0017] The thickness of the glassine paper constituting the first substrate is preferably 5 to 50 μm, more preferably 10 to 40 μm, in consideration of the strength as a support and the flexibility during handling. Since various types of glassine paper constituting the first substrate are commercially available, those skilled in the art can appropriately select a suitable one from them.

[0018] Note that in the present invention, it is not essential for the first substrate to be composed of glassine paper, and it can also be composed of a transparent plastic. As the transparent plastic, those conventionally commonly used as the substrate of adhesive tapes can be adopted. For example, a PET film, a polypropylene film, or a polyethylene film can be adopted. The thickness of these films is preferably 5 to 50 μm, more preferably 10 to 40 μm, in consideration of the strength as a support and the flexibility during handling. Since various types of these films are commercially available, those skilled in the art can appropriately select a suitable one from them.

[0019] In the present invention, the printed layer is a layer on which characters, symbols, patterns, etc., are printed with ink, and can represent information such as the name of a vegetable or fresh flower shipper, brand name, store name, barcode, or QR code (registered trademark). In the present invention, the printed layer is not exposed on the surface of the adhesive tape and is covered by a second substrate. Therefore, in the adhesive tape of the present invention, since the printed layer does not have the potential to come into direct contact with food, inks other than those compliant with the Food Sanitation Law can be used, and there are no restrictions on the ink used for the printed layer. The printed layer can be formed by conventionally known methods. For example, the printed layer can be formed by gravure printing a solvent-type colored ink and then drying and curing it, and in particular, it can be formed by pitch printing, which involves repeatedly printing the same design. The thickness of the printed layer is, for example, 0.1 to 5 μm, preferably 0.3 to 3 μm.

[0020] The present invention is characterized in that the second base material is made of glassine paper. Glassine paper is semi-transparent and has higher transparency than crepe paper or Japanese paper, which are conventionally used as paper base materials for adhesive tapes. Therefore, glassine paper can be used as a substitute for transparent plastic base materials to cover the printed layer without causing any problems with visibility. In addition, glassine paper has better recyclability than ordinary paper and is more environmentally friendly. Furthermore, glassine paper has better smoothness than ordinary paper, resulting in superior adhesion between adjacent layers. The thickness of the glassine paper constituting the second base material is preferably 5 to 50 μm, and more preferably 10 to 40 μm, considering the balance between strength as a cover for the printed layer and flexibility during handling. As with the first base material, suitable glassine paper can be appropriately selected from various commercially available products as the glassine paper constituting the second base material.

[0021] In the adhesive tape of the present invention, a primer layer may be placed between the adhesive layer and the first substrate, if necessary. The primer layer serves to improve the adhesion between the adhesive layer and the first substrate. The constituent material of the primer layer can be appropriately selected according to the constituent material of the adhesive layer, and for example, resins such as acrylic, rubber, urethane, and epoxy resins can be used. The thickness of the primer layer is, for example, 0.08 to 5 μm, preferably 0.5 to 3 μm.

[0022] In the adhesive tape of the present invention, an adhesive layer may be placed between the printed layer and the second substrate, or between the first substrate and the printed layer, as needed. The adhesive layer serves to improve the adhesion between the printed layer and the substrate. As the adhesive constituting the adhesive layer, conventionally known adhesives such as solution-type urethane resin adhesives, epoxy resin adhesives, and polyester resin adhesives can be used. The thickness of the adhesive layer is, for example, 0.1 to 10 μm, preferably 1 to 5 μm.

[0023] In the adhesive tape of the present invention, a release agent layer may be placed on the second substrate as needed. The release agent layer serves to facilitate the unwinding of the adhesive tape when it is wound in a roll. As the constituent material of the release agent layer, known release agents such as long-chain alkyl release agents and silicone release agents can be used. The basis weight of the release agent layer is, for example, 0.1 to 10 g / m². 2 Preferably 0.1 to 3 g / m 2 That is the case.

[0024] Next, Figure 4 shows another example of the layer configuration of the adhesive tape of the present invention. The adhesive tape in Figure 4 has the same layer configuration as the adhesive tape in Figure 3, except that the position of the adhesive layer is different from that of the adhesive tape in Figure 3. That is, in Figure 3, the adhesive layer is located between the printed layer and the second substrate, whereas in Figure 4, the adhesive layer is located between the first substrate and the printed layer. This difference in arrangement stems from the fact that Figure 3 corresponds to a type where the printed layer is printed on the front, while Figure 4 corresponds to a type where the printed layer is printed on the back. In the adhesive tape of the present invention, since the second substrate is made of highly transparent glassine paper, fine information such as barcodes and QR codes (registered trademarks) can be read sufficiently even in the type with back printing as shown in Figure 4.

[0025] Next, the manufacturing procedure for the adhesive tape of the present invention will be described with reference to Figure 5. The adhesive tape of the present invention can be manufactured by conventionally known methods as appropriate. For example, in the case of the type shown in Figure 3, the adhesive tape can be manufactured by the following procedure.

[0026] First, a printed layer is formed on one side of the glassine paper, which will serve as the first base material, by printing letters, symbols, or designs with ink. Next, a primer is applied to the side of the glassine paper opposite to the printed layer to form a primer layer, creating a laminate (1) as shown in the upper left of Figure 5. Meanwhile, a release agent is applied to one side of the glassine paper, which will serve as the second base material, to form a release agent layer. Next, an adhesive is applied to the side of the glassine paper opposite to the release agent layer to form an adhesive layer, creating a laminate (2) as shown in the upper right of Figure 5. Next, these laminates (1) and laminate (2) are bonded together so that the printed layer of laminate (1) is in contact with the adhesive layer of laminate (2), creating a laminate (3) as shown in the lower left of Figure 5. Finally, an adhesive is applied to the primer layer of this laminate (3) to form an adhesive layer, completing the adhesive tape as shown in the lower right of Figure 5.

[0027] In the case of the type shown in Figure 4, adhesive tape can be manufactured in a similar manner by changing the formation procedure of laminate (1) and laminate (2) according to the differences in the layer configuration.

[0028] The adhesive tape of the present invention, manufactured in this manner, can be provided in a roll form by winding it around a core for ease of handling. In the case of a rolled adhesive tape, it can be used by unwinding and cutting only the required length.

[0029] Next, Figure 6 shows specific examples of the use of the adhesive tape of the present invention. In Figure 6, Example 1 is an example of its use in bundling vegetables such as spinach, Example 2 is an example of its use in sealing containers and packaging of food such as prepared foods, Example 3 is an example of its use in identifying purchased goods for the purpose of preventing shoplifting, and Example 4 is an example of its use in identifying goods for the purpose of detecting tampering. In addition to these, the adhesive tape of the present invention can also be used as an industrial tape, taking advantage of its good heat resistance and low heat shrinkage.

[0030] The effects of the adhesive tape of the present invention are demonstrated by the following examples, but the present invention is not limited to these examples. [Examples]

[0031] Examples of the present invention As an example of the present invention, an adhesive tape was prepared with layers arranged in the order shown in Figure 3. The constituent materials and layer thicknesses of each layer of the adhesive tape are as shown in Table 1 below.

[0032] [Table 1] ------------------------------------------------------------------ Layer Constituent Material Thickness (μm) ------------------------------------------------------------------ Release agent layer: Long-chain alkyl release agent 0.5 Second base material: Glassine paper 31.5 Adhesive layer: Polyester resin 3.0 Printing layer: Printing ink (solvent type) 1.0 First base material: Glassine paper 31.5 Primer layer: Rubber-based resin 1.0 Adhesive layer: Rubber-based adhesive 25.0 ------------------------------------------------------------------

[0033] Specifically, first, a barcode was repeatedly pitch-printed onto one side of the first substrate, glassine paper, using a solvent-based printing ink to form a printed layer. Next, a rubber-based resin was applied as a primer to the side of the glassine paper opposite to the printed layer to form a primer layer, creating a laminate (1) as shown in the upper left of Figure 5. Meanwhile, a long-chain alkyl-based release agent was applied as a release agent to one side of the second substrate, glassine paper, to form a release agent layer. Next, a polyester-based resin adhesive was applied as an adhesive to the side of the glassine paper opposite to the release agent layer to form an adhesive layer, creating a laminate (2) as shown in the upper right of Figure 5. Finally, these laminates (1) and (2) were bonded together so that the printed layer of laminate (1) was in contact with the adhesive layer of laminate (2), creating a laminate (3) as shown in the lower left of Figure 5. Finally, a rubber-based adhesive was applied as an adhesive to the primer layer of this laminate (3) to form an adhesive layer, completing the adhesive tape shown in the lower right of Figure 5.

[0034] The visibility and readability of the barcode on the printed layer of the manufactured adhesive tape were checked and found to be at a level that poses no practical problems. Furthermore, the pitch printing was performed without any issues, and despite the thinness of the primer and adhesive layers, the adhesion to adjacent layers was excellent.

[0035] Comparative Example As a comparative example, an attempt was made to produce an adhesive tape in the same manner as in the present invention, except that the constituent materials of the first and second substrates were changed to 31.5 μm thick Japanese paper, which is commonly used as a paper substrate for adhesive tapes. However, at the stage of pitch printing of the printing layer, the Japanese paper of the first substrate underwent thermal shrinkage due to the sealing resin it contained, making it impossible to perform proper pitch printing.

[0036] Furthermore, when the visibility and readability of the barcode on the printed layer of the manufactured adhesive tape were checked, the barcode was almost invisible and could not be read by the reader. In addition, because the Japanese paper has an uneven surface, its adhesion to adjacent layers was poor, and it was necessary to increase the thickness of the primer layer and adhesive layer. [Industrial applicability]

[0037] The adhesive tape of the present invention can overcome conventional problems such as wear and peeling of the printed layer and limitations on the ink used for the printed layer, while maintaining the visibility of the printed layer. Furthermore, the adhesive tape of the present invention is highly recyclable and environmentally friendly, suitable for pitch printing where the same design is printed repeatedly, and also exhibits excellent adhesion between adjacent layers. Therefore, the adhesive tape of the present invention can be suitably used for bundling various materials, sealing various containers and bags, or for product identification marking.

Claims

1. An adhesive tape comprising a first substrate, a second substrate, an adhesive layer, and a printed layer, wherein the printed layer is disposed between the first substrate and the second substrate, the adhesive layer is disposed on the side of the first substrate where the printed layer is absent, the first substrate and the second substrate are made of glassine paper, and the adhesive tape is used for bundling vegetables or fresh flowers, or for sealing food containers or packaging bags.

2. The adhesive tape according to claim 1, characterized in that a primer layer is disposed between the adhesive layer and the first substrate, an adhesive layer is disposed between the printed layer and the second substrate, and a release agent layer is disposed on the side of the second substrate where the adhesive layer is absent.

3. The adhesive tape according to claim 1, characterized in that a primer layer is disposed between the adhesive layer and the first substrate, an adhesive layer is disposed between the first substrate and the printed layer, and a release agent layer is disposed on the side of the second substrate where the printed layer is absent.

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