PVC adhesive tape

Abstract

To provide a PVC adhesive tape capable of reduction of possibility of workability deterioration.SOLUTION: A PVC adhesive tape 1 includes a substrate sheet 10 containing PVC as the main component and a pressure-sensitive adhesive 20 provided at least on one surface of the substrate sheet 10, wherein the substrate sheet 10 is constituted of a first material containing PVC as the main component and a second material containing the first material and the pressure-sensitive adhesive 20, and a ratio of the second material to 100 pts.wt. of the first material is 30 pts.wt. or under, and a polymerization degree of PVC is 1500 or under.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a PVC adhesive tape. [Background technology]

[0002] Conventionally, adhesive tapes have been proposed that include a base sheet and an adhesive formed on one side of the base sheet (see Patent Documents 1 and 2). Also, adhesive tapes have been proposed that use a base sheet whose main component is PVC (polyvinyl chloride) (see Patent Document 3). Such adhesive tapes incur losses during production. These losses are reused in the production of base sheets (see Patent Documents 3 to 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-199992 [Patent Document 2] Patent Publication No. 2021-151113 [Patent Document 3] Japanese Patent Application Publication No. 6-318414 [Patent Document 4] Japanese Patent Application Publication No. 5-309791 [Patent Document 5] Japanese Patent Application Publication No. 2002-285116 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, losses during production may occur before or after application of the adhesive. The adhesive is applied to the central portion of the base sheet, excluding the areas near both ends in the width direction, so after application, the areas near both ends of the base sheet are free of adhesive. Therefore, the losses before and after application of the adhesive, both ends of the base sheet, are recycled for the manufacture of the base sheet. On the other hand, the central portion of the base sheet after application tends to be discarded without being recycled, since the adhesive is applied to the central portion.

[0005] Therefore, Patent Documents 3 to 5 propose recycling base sheets coated with adhesive. For example, the PVC adhesive tape described in Patent Document 3 limits the amount of product loss (recycled amount) containing adhesive to a predetermined weight percent or less, thereby preventing the inclusion of more adhesive than necessary and suppressing deterioration of the properties of the base sheet.

[0006] However, the applicant of the present invention has found that simply considering the amount of recycled product loss containing adhesives may result in a deterioration in workability when using PVC adhesive tape.

[0007] The present invention has been made to solve these conventional problems, and an object of the present invention is to provide a PVC pressure-sensitive adhesive tape that can reduce the possibility of deterioration in workability. [Means for solving the problem]

[0008] The PVC adhesive tape according to the present invention is a PVC adhesive tape having a base sheet whose main component is polyvinyl chloride and an adhesive formed on at least one surface of the base sheet, wherein the base sheet is composed of 100 parts by weight of a first material whose main component is polyvinyl chloride and 30 parts by weight or less of a second material in which the adhesive is added to the first material, and the degree of polymerization of the polyvinyl chloride is 1500 or less. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a PVC pressure-sensitive adhesive tape that can reduce the possibility of deterioration in workability. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a PVC pressure-sensitive adhesive tape according to an embodiment of the present invention. [Figure 2] 1A to 1C are process diagrams showing a method for manufacturing a substrate sheet. [Figure 3] 1 is a table showing Examples 1 and 2 and Comparative Examples 1 to 4. [Figure 4] 1 is a table showing Examples 3 and 4 and Comparative Examples 5 to 8. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below in accordance with preferred embodiments. Note that the present invention is not limited to the embodiments shown below and can be modified as appropriate without departing from the spirit of the present invention. In addition, in the embodiments shown below, some components are omitted from illustration and description, but it goes without saying that publicly known or well-known technologies are applied as appropriate to the details of the omitted technologies within the scope of the content described below.

[0012] Fig. 1 is a cross-sectional view showing a PVC pressure-sensitive adhesive tape according to an embodiment of the present invention. As shown in Fig. 1, the PVC pressure-sensitive adhesive tape 1 according to this embodiment is composed of a base sheet 10 containing PVC as a main component, and a pressure-sensitive adhesive 20 formed on one side of the base sheet 10. The PVC pressure-sensitive adhesive tape 1 may be a double-sided tape in which the pressure-sensitive adhesive 20 is formed on both one and the other sides of the base sheet 10.

[0013] The adhesive 20 is made of, for example, any one of acrylic resin, silicone resin, rubber-based adhesive (including NR (natural rubber) and SIS (styrene-isoprene-styrene rubber)), urethane adhesive, or a combination thereof. Note that the adhesive 20 is not limited to the above-mentioned materials as long as it exhibits a predetermined level of adhesive strength.

[0014] In this embodiment, the base sheet 10 is composed of a first material whose main component is PVC, and a second material that includes the first material and an adhesive 20. More specifically, the first material includes a PVC resin, a plasticizer (e.g., diisononyl phthalate), calcium carbonate, and a stabilizer. The second material includes the adhesive 20 in addition to the first material. That is, the second material includes a PVC resin, a plasticizer, calcium carbonate, a stabilizer, and an adhesive 20.

[0015] Here, losses during the production of the PVC adhesive tape 1 include those that contain the adhesive 20 and those that do not. For example, losses before the gluing process in which the adhesive 20 is applied to the base sheet 10 do not contain the adhesive 20. Furthermore, even after the gluing process, portions of the base sheet 10 to which the adhesive 20 has not been applied are losses that do not contain the adhesive 20. In contrast, portions of the base sheet 10 to which the adhesive 20 has been applied after the gluing process are losses that contain the adhesive 20.

[0016] The first material can be a material prepared by blending PVC resin, plasticizer, calcium carbonate, and stabilizer in a predetermined ratio, or waste from production that does not contain adhesive 20. On the other hand, the second material can be waste from production that does not contain adhesive 20.

[0017] Furthermore, since the PVC pressure-sensitive adhesive tape 1 according to this embodiment uses the second material in the base sheet 10, the base sheet 10 contains unnecessary PSA 20. Therefore, in this embodiment, the ratio of the second material to 100 parts by weight of the first material is set to 30 parts by weight or less. By limiting the amount of the second material used in this manner, the base sheet 10 is improved in terms of manufacturability and appearance. Here, "good manufacturability" refers to a state in which the base sheet 10 does not stick to the roll during molding, preventing it from being released from the mold. Furthermore, "good appearance" refers to a state in which the base sheet 10 is free of pinholes and color unevenness, and the surface of the base sheet 10 can be visually determined to be smooth.

[0018] Additionally, in this embodiment, the PVC that is the main component of the first material and the PVC contained in the second material have a degree of polymerization of 1500 or less. If the degree of polymerization of PVC exceeds 1500, the strength of the base sheet 10 increases, making it difficult to tear, and workability tends to deteriorate. However, in the PVC pressure-sensitive adhesive tape 1 according to this embodiment, the degree of polymerization of PVC is 1500 or less. Therefore, it is possible to provide a PVC pressure-sensitive adhesive tape 1 that can reduce the possibility of workability deterioration.

[0019] Here, the degree of polymerization of PVC is preferably 1000 or more. If the degree of polymerization of PVC is less than 1000, the thermal stability deteriorates, and the heat resistance life of the tape tends to deteriorate. Therefore, by ensuring that the degree of polymerization of PVC is 1000 or more, it is possible to provide a PVC pressure-sensitive adhesive tape 1 with a longer heat resistance life of the tape.

[0020] In the above, the proportion of adhesive 20 in the second material is 11% by weight or more and 20% by weight or less, and preferably 15% by weight or more and 19% by weight or less. More specifically, when the degree of polymerization of PVC is 1000, the proportion of adhesive 20 in the second material is preferably 11% by weight or more and 19% by weight or less. Furthermore, when the degree of polymerization of PVC is 1500, the proportion of adhesive 20 in the second material is preferably 15% by weight or more and 20% by weight or less.

[0021] Next, a method for manufacturing the base sheet 10 of the PVC pressure-sensitive adhesive tape 1 according to this embodiment will be described. Fig. 2 is a process diagram showing the method for manufacturing the base sheet 10. As shown in Fig. 2, the base sheet 10 of the PVC pressure-sensitive adhesive tape 1 is manufactured through a primary kneading process, a secondary kneading process, a foreign matter removal process, a film forming process, a thickness control process, a cooling process, and a winding process.

[0022] The first kneading process is a kneading process using a so-called Banbury mixer, and the second kneading process is a kneading process using a so-called mixing roll. In these processes, resins and the like are kneaded to produce the base sheet 10. The first material (i.e., PVC resin, plasticizer, calcium carbonate, and stabilizer) and the second material (i.e., recycled material including adhesive 20) are added and kneaded in the first kneading process.

[0023] The foreign matter removal process is a process of removing solids and the like using a strainer. The film molding process is a process of molding the material that has undergone the foreign matter removal process into a film using a calendar roll. The thickness control process is a process of adjusting the film obtained in the film molding process to a thickness appropriate for the base sheet 10 using a take-off roll.

[0024] The cooling process is a process of cooling the film (base sheet 10) that has been adjusted to an appropriate thickness in the thickness control process, and the winding process is a process of winding up the cooled base sheet 10 around a paper tube or the like as a central member.

[0025] After the base sheet 10 is manufactured as described above, a gluing step and the like are carried out to apply the adhesive 20, and the PVC adhesive tape 1 is manufactured by cutting the base sheet 10 in a predetermined manner in a cutting step.

[0026] Next, examples and comparative examples will be described. Fig. 3 is a chart showing examples 1 and 2 and comparative examples 1 to 4, and Fig. 4 is a chart showing examples 3 and 4 and comparative examples 5 to 8. Fig. 3 shows examples and comparative examples using PVC with a degree of polymerization of 1000, and Fig. 4 shows examples and comparative examples using PVC with a degree of polymerization of 1500. In Fig. 3, various second materials with an adhesive ratio of 11% by weight or more and 19% by weight or less were used, and in Fig. 4, various second materials with an adhesive ratio of 15% by weight or more and 20% by weight or less were used.

[0027] As shown in Fig. 3, the PVC adhesive tape according to Comparative Example 1 was produced using 100 parts by weight of the first material and no recycled second material. The PVC adhesive tape according to Example 1 was produced using 100 parts by weight of the first material and 15 parts by weight of the recycled second material. The PVC adhesive tape according to Example 2 was produced using 100 parts by weight of the first material and 30 parts by weight of the recycled second material.

[0028] The PVC adhesive tape according to Comparative Example 2 was produced using 100 parts by weight of the first material and 100 parts by weight of the recycled second material. The PVC adhesive tape according to Comparative Example 3 was produced using 100 parts by weight of the first material and 300 parts by weight of the recycled second material. The PVC adhesive tape according to Comparative Example 4 was produced using only the second material, without using the first material.

[0029] 4, the PVC adhesive tape according to Comparative Example 5 was produced using 100 parts by weight of the first material and no recycled material as the second material. The PVC adhesive tape according to Example 3 was produced using 100 parts by weight of the first material and 15 parts by weight of the recycled material as the second material. The PVC adhesive tape according to Example 4 was produced using 100 parts by weight of the first material and 30 parts by weight of the recycled material as the second material.

[0030] The PVC adhesive tape according to Comparative Example 6 was produced using 100 parts by weight of the first material and 100 parts by weight of the recycled second material. The PVC adhesive tape according to Comparative Example 7 was produced using 100 parts by weight of the first material and 300 parts by weight of the recycled second material. The PVC adhesive tape according to Comparative Example 8 was produced using only the second material, without using the first material.

[0031] The PVC pressure-sensitive adhesive tapes of Examples 1 to 4 and Comparative Examples 1 to 8 were evaluated for manufacturability, appearance, and tape workability, and their initial strength and breaking strength were measured.

[0032] Manufacturability is an item evaluated based on whether the film (substrate sheet) sticks to the roll during molding and cannot be released from the mold, with those that cannot be released being evaluated as "X" and those that can be released being evaluated as "O". Appearance is an item evaluated based on the presence or absence of pinholes, color unevenness, and whether the surface is smooth after film molding. Films without pinholes, color unevenness, and a smooth surface were evaluated as "O", and those that did not satisfy any one of these were evaluated as "X".

[0033] Tape workability is an item evaluated based on whether the PVC adhesive tape can be torn relatively easily by hand by a worker during the production of wire harnesses. Tapes with an initial strength of less than 7N were evaluated as "Good," and those with an initial strength of 7N or more were evaluated as "Poor."

[0034] 3 and 4 show the initial strength and breaking strength as measured by a tensile strength test in accordance with JIS C2107. Also, in FIG. 3 (excluding Comparative Example 1), various second materials with adhesive ratios of 11% by weight or more and 19% by weight or less were used. Therefore, in FIG. 3, the manufacturability, appearance, and tape workability were all marked with "Good" when various second materials were used. Furthermore, the initial strength and breaking strength show the highest values ​​when various second materials were used. The same is true for FIG. 4 (excluding Comparative Example 5).

[0035] First, the PVC adhesive tapes according to Comparative Examples 1 and 5 do not use the second material, but only the first material. Therefore, manufacturability, appearance, and tape workability were all rated "Good." The initial strength and breaking strength of Comparative Example 1 were 5N and 37N, respectively, and the initial strength and breaking strength of Comparative Example 5 were 5N and 38N, respectively.

[0036] Furthermore, the PVC adhesive tapes according to Examples 1 and 3 use only 15 parts by weight of the second material relative to 100 parts by weight of the first material. The PVC adhesive tapes according to Examples 1 and 3 were evaluated as "good" in terms of manufacturability, appearance, and tape workability. The initial strength and breaking strength of Example 1 were 5N and 32N, respectively, and the initial strength and breaking strength of Example 3 were 5N and 37N, respectively.

[0037] The PVC pressure-sensitive adhesive tapes of Examples 2 and 4 use only 30 parts by weight of the second material relative to 100 parts by weight of the first material. The PVC pressure-sensitive adhesive tapes of Examples 2 and 4 were evaluated as "good" in terms of manufacturability, appearance, and tape workability, similar to Examples 1 and 3. The initial strength and breaking strength of Example 2 were 5 N and 32 N, respectively, and the initial strength and breaking strength of Example 4 were 5 N and 35 N, respectively.

[0038] The PVC pressure-sensitive adhesive tapes according to Comparative Examples 2 and 6 use 100 parts by weight of the second material relative to 100 parts by weight of the first material. The PVC pressure-sensitive adhesive tapes according to Comparative Examples 2 and 6 were rated "good" for manufacturability, but "poor" for appearance and tape workability. The initial strength and breaking strength of Comparative Example 2 were 8N and 42N, respectively, and the initial strength and breaking strength of Comparative Example 6 were 9N and 43N, respectively.

[0039] The PVC pressure-sensitive adhesive tapes according to Comparative Examples 3 and 7 use 300 parts by weight of the second material relative to 100 parts by weight of the first material. The PVC pressure-sensitive adhesive tapes according to Comparative Examples 3 and 7 were rated "good" for manufacturability, but "poor" for appearance and tape workability. The initial strength and breaking strength of Comparative Example 3 were 10 N and 44 N, respectively, and the initial strength and breaking strength of Comparative Example 7 were 11 N and 44 N, respectively.

[0040] The PVC pressure-sensitive adhesive tapes according to Comparative Examples 4 and 8 use only the second material without using the first material. The PVC pressure-sensitive adhesive tapes according to Comparative Examples 4 and 8 were rated "x" not only for appearance but also for manufacturability. While the initial strength and breaking strength of Comparative Example 4 were not measured, it can be said that the initial strength was at least 10 N or more and the breaking strength was at least 44 N or more, based on the results of the other Examples and Comparative Examples. Based on the above, the tape workability was also rated "x". Similarly, the initial strength and breaking strength of Comparative Example 8 were not measured, but it can be said that the initial strength was at least 11 N or more and the breaking strength was at least 44 N or more, and the tape workability was also rated "x".

[0041] From the above, it was found that when PVC with a degree of polymerization of at least 1000 and 1500 is used and the second material is 30 parts by weight or less per 100 parts by weight of the first material, good results are obtained in terms of manufacturability, appearance, and tape workability.

[0042] In addition, the higher the degree of polymerization of PVC, the stronger it becomes and the harder it is to tear. Therefore, even if the degree of polymerization is less than 1000, it can be said that the tape workability is good.

[0043] Thus, in the PVC pressure-sensitive adhesive tape 1 according to this embodiment, the base sheet 10 is composed of a first material primarily composed of PVC and a second material containing the first material and a pressure-sensitive adhesive 20. Furthermore, the proportion of the second material per 100 parts by weight of the first material is 30 parts by weight or less, and the degree of polymerization of PVC is 1500 or less. Here, if the degree of polymerization of PVC is high, the strength of the base sheet 10 increases, making it difficult to tear, and workability tends to deteriorate. Therefore, by ensuring that the proportion of the second material is 30 parts by weight or less and that the degree of polymerization of PVC is 1500 or less, the workability of the base sheet 10 is easily ensured. Therefore, a PVC pressure-sensitive adhesive tape 1 can be provided that can reduce the possibility of workability deterioration.

[0044] Furthermore, since the PVC adhesive tape 1 according to this embodiment has a degree of polymerization of PVC of 1000 or more, it is possible to prevent the PVC from having an excessively low degree of polymerization, which would result in poor thermal stability and a shortened heat resistance life of the tape.

[0045] Furthermore, in the PVC pressure-sensitive adhesive tape 1 according to this embodiment, the proportion of the pressure-sensitive adhesive 20 in the second material is 15% by weight or more and 19% by weight or less. This makes it possible to provide a PVC pressure-sensitive adhesive tape 1 that contains an appropriate amount of pressure-sensitive adhesive 20 while reducing deterioration in the properties of the base sheet 10.

[0046] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and modifications may be made within the scope of the spirit of the present invention, and if possible, publicly known or well-known technologies may be combined.

[0047] For example, in this embodiment, it is described that the proportion of the adhesive 20 in the second material is 11% by weight or more and 20% by weight or less, and preferably 15% by weight or more and 19% by weight or less. However, this is not limited thereto, and the proportion of the adhesive 20 in the second material may be less than 11% by weight or 15% by weight. Furthermore, when the amount of the second material used in the base sheet 10 is significantly less than 30 parts by weight, the proportion of the adhesive 20 in the second material may be more than 20% by weight or 19% by weight. [Explanation of symbols]

[0048] 1: PVC adhesive tape 10: Base sheet 20: Adhesive

Claims

1. A PVC adhesive tape having a base sheet mainly composed of polyvinyl chloride and an adhesive formed on at least one surface of the base sheet, the base sheet is composed of 100 parts by weight of the first material mainly composed of polyvinyl chloride and 30 parts by weight or less of the second material obtained by adding the adhesive to the first material, The degree of polymerization of the polyvinyl chloride is 1500 or less. A PVC adhesive tape characterized by:

2. The degree of polymerization of the polyvinyl chloride is 1000 or more.

2. The PVC adhesive tape according to claim 1.

3. The proportion of the adhesive in the second material is 15% by weight or more and 19% by weight or less.

2. The PVC adhesive tape according to claim 1.

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