Adhesive tape

Abstract

To provide an adhesive composition or the like that can prevent an end of an adhesive tape from being peeled off.SOLUTION: An adhesive composition contains an adhesive and an organic solvent. The adhesive composition is applied to a fibrous base fabric in order to make an adhesive tape. The adhesive contains an acrylic polymer, and the organic solvent contains ethyl acetate. There is also provided an adhesive tape including the adhesive composition.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an adhesive composition and an adhesive tape. [Background technology]

[0002] Conventionally, adhesive tapes for bundling a plurality of electric wires in, for example, a wire harness have been known. This type of adhesive tape has, for example, a strip-shaped support film and an adhesive composition layer laminated on one surface of the support film.

[0003] Specifically, as this type of adhesive tape, there is known an adhesive tape comprising a support containing polyvinyl chloride having a predetermined polymerization degree and an adhesive composition layer containing a (meth)acrylic polymer having no nitrogen atoms in the molecule (for example, Patent Document 1).

[0004] The adhesive tape described in Patent Document 1 is used repeatedly in a high-temperature environment in a state where it is wound around a plurality of electric wires in, for example, a wire harness in an engine room. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-076409 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional adhesive tape described in Patent Document 1 and the like has a problem that when used in a wound state under the above-mentioned environment, the outermost wound end portion may peel off. In other words, the tape has a problem that peeling at the end portion is relatively likely to occur.

[0007] In view of the above problems, an object of the present invention is to provide an adhesive composition capable of suppressing edge peeling of an adhesive tape, and an adhesive tape suppressed from edge peeling. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a pressure-sensitive adhesive composition that contains a pressure-sensitive adhesive and an organic solvent, and is used by being applied to a fiber base fabric to produce a pressure-sensitive adhesive tape, the pressure-sensitive adhesive composition comprising: The pressure-sensitive adhesive contains an acrylic polymer, The organic solvent contains ethyl acetate.

[0009] The above-mentioned adhesive composition can be applied to a fiber base fabric to impart adhesiveness when producing an adhesive tape. Since the acrylic polymer has an ester bond in the molecule, similar to ethyl acetate, in the above-mentioned adhesive composition, the acrylic polymer is dissolved in ethyl acetate. When the above-mentioned adhesive composition is applied to a fiber base fabric, the acrylic polymer and ethyl acetate are impregnated into the fiber base fabric while the ethyl acetate is volatilized. As the ethyl acetate volatilization progresses, the viscosity of the composition increases and it becomes difficult to impregnate, so the impregnation speed slows down and the impregnation stops with the ethyl acetate volatilization. Moreover, since ethyl acetate has a relatively high vapor pressure, it volatilizes relatively quickly after application, so the acrylic polymer only penetrates into a relatively shallow part of the fiber base fabric. In the surface layer portion of the fiber base fabric into which the acrylic polymer has penetrated, the acrylic polymer has penetrated into the gaps between the fibers of the fiber base fabric. Therefore, the surface layer portion becomes harder than before impregnation by the amount of the acrylic polymer that has penetrated into the gaps. The pressure-sensitive adhesive tape produced after volatilization becomes harder than the fiber base fabric by the amount of the surface layer portion that has become harder. However, as described above, the acrylic polymer penetrates into the fiber base fabric only to a relatively shallow portion, resulting in a shallow impregnation depth. In other words, the thickness of the hardened surface layer is thin. For example, the thickness of the hardened surface layer can be made less than half the thickness of the fiber base fabric. This allows the adhesive tape to maintain a relatively soft state without losing much of the softness of the fiber base fabric itself. Therefore, even if the adhesive tape is wound around an object such as a plurality of electric wires and is left for a long period of time at high temperatures, the phenomenon of the end portions peeling off due to the rigidity of the adhesive tape itself can be suppressed by the softness. In other words, the end portions that are wound and attached in a curved state and are not pressed from the outside tend to maintain that state due to their softness. Therefore, peeling at the end portions can be suppressed.

[0010] The pressure-sensitive adhesive tape according to the present invention is an adhesive tape comprising a fiber base fabric and an adhesive layer overlapping one surface of the fiber base fabric, the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive containing an acrylic polymer, In the fiber base fabric, a surface layer portion overlapping the pressure-sensitive adhesive layer is impregnated with the pressure-sensitive adhesive, The adhesive is impregnated into the fiber base fabric to a depth less than half the thickness of the fiber base fabric.

[0011] In the above-mentioned pressure-sensitive adhesive tape, the impregnation depth of the pressure-sensitive adhesive is less than half the thickness of the fiber base fabric, and therefore the pressure-sensitive adhesive tape can maintain a relatively soft state for the same reason as described above. Therefore, as described above, the pressure-sensitive adhesive tape can suppress edge peeling when used by being wrapped around an object.

[0012] In the pressure-sensitive adhesive tape according to the present invention, it is preferable that the material of the fiber base fabric is such that a contact angle of ethyl acetate with a film formed from the material is 13° or more. With this configuration, the wettability of the fiber base fabric with ethyl acetate is relatively low, so that the impregnation depth of the acrylic polymer into the fiber base fabric is more reliably shallower, and therefore, for the same reasons as described above, peeling at the end portions can be more reliably suppressed. Effect of the Invention

[0013] The adhesive composition according to the present invention can suppress edge peeling of an adhesive tape. Furthermore, the adhesive tape according to the present invention is suppressed from edge peeling during use. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing the appearance of an adhesive tape according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 . [Diagram 3] FIG. 2 is a schematic cross-sectional view of the adhesive tape of the present embodiment wrapped around a plurality of electric wires. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, one embodiment of the pressure-sensitive adhesive tape according to the present invention will be described with reference to the drawings.

[0016] The pressure-sensitive adhesive tape 1 of this embodiment includes a fiber base fabric 2 and a pressure-sensitive adhesive layer 3 overlapping one surface of the fiber base fabric 2. As shown in Fig. 1 and Fig. 2, the pressure-sensitive adhesive tape 1 of this embodiment is formed in a strip shape (long sheet shape). The pressure-sensitive adhesive layer 3 is formed from a pressure-sensitive adhesive containing an acrylic polymer. The surface layer of the fiber base fabric 2 that overlaps with the adhesive layer 3 is impregnated with the adhesive, and the depth of impregnation of the fiber base fabric 2 with the adhesive is less than half the thickness of the fiber base fabric 2 .

[0017] The adhesive is formed by volatilizing an organic solvent (containing ethyl acetate) contained in an adhesive composition (described in detail later). As described below, the adhesive layer 3 is formed by applying an adhesive composition to one surface of the fiber base fabric 2. A part of the adhesive composition penetrates into the surface layer of the fiber base fabric 2 that overlaps with the adhesive layer 3. Thereafter, the organic solvent volatilizes, so that the surface layer of the fiber base fabric 2 becomes impregnated with the adhesive.

[0018] The thickness of the pressure-sensitive adhesive layer 3 may be, for example, 1 / 12 to 1 / 3, or 1 / 7 to 1 / 3, of the thickness of the fiber base fabric 2. Specifically, the thickness of the pressure-sensitive adhesive layer 3 may be 20 μm to 50 μm.

[0019] The adhesive is impregnated on one side of the fiber base fabric 2. In other words, the adhesive penetrates into the gaps between the fibers and reaches a predetermined depth in the thickness direction from one side of the fiber base fabric 2. The impregnation depth of the adhesive into the fiber base fabric 2 is less than 1 / 2 of the thickness of the fiber base fabric 2. Such an impregnation depth is usually 1 / 4 or more.

[0020] The impregnation depth of the adhesive is measured as follows. Specifically, a cross section of the adhesive sheet cut in the thickness direction is observed under a microscope. In the cross section, the area impregnated with the adhesive and the area not impregnated with the adhesive can be distinguished by the difference in contrast. The deepest impregnation depth in the thickness direction is determined as the above impregnation depth.

[0021] The material of the fibers constituting the fiber base fabric 2 is, for example, acetate (cellulose acetate), polyester such as polyethylene terephthalate, polyamide, polypropylene, polyurethane, or the like.

[0022] The material of the fiber base fabric 2 is preferably a material that provides a contact angle of ethyl acetate to a film formed from the material of 13° or more. Examples of such materials include acetate and polypropylene. In other words, the fibers constituting the fiber base fabric 2 are preferably at least one of acetate fibers and polypropylene fibers. The material of the fiber base fabric 2 may be a material that provides a contact angle of 20° or less. By using such a material for the fiber base fabric 2, the wettability of the fiber base fabric 2 with ethyl acetate becomes relatively low, so that edge peeling of the adhesive tape 1 can be more reliably suppressed. The reason for this will be explained later.

[0023] The contact angle is measured as follows. Specifically, in an environment of 23°C, a static contact angle is measured 0.1 seconds after dropping 4 μL of ethyl acetate using a contact angle meter. The contact angle is determined by calculating the average of three measured values. The film used in the contact angle measurement is a film made of the same material as the material of the fibers constituting the fiber base fabric 2, and has a smooth surface.

[0024] The fiber base fabric 2 may be a woven fabric or a nonwoven fabric. The fiber base fabric 2 may be formed of an independent single fiber (monofilament), or may be formed of a yarn (multifilament) in which single fibers are gathered together. The thickness (cross-sectional diameter) of the single fiber (monofilament) constituting the fiber base fabric 2 is, for example, 10 μm or more and 50 μm or less. The thickness of the yarn (multifilament) constituting the fiber base fabric 2 is, for example, 80 decitex or more and 170 decitex or less. The yarn density of the yarns constituting the fiber base fabric 2 may be, for example, 19 yarns / 10 mm or more and 79 yarns / 10 mm or less.

[0025] The fiber base fabric 2 is preferably woven with warp threads extending in the longitudinal direction of the tape and weft threads intersecting in a direction perpendicular to the warp threads, which allows the pressure-sensitive adhesive tape 1 to have good hand-tearability. The fiber base fabric 2 may be a plain weave of warp threads and weft threads, a twill weave of warp threads and weft threads, or a satin weave of warp threads and weft threads.

[0026] The thickness of the fiber base fabric 2 is, for example, 150 μm or more and 210 μm or less. The thickness of the pressure-sensitive adhesive tape 1 of this embodiment may be, for example, 170 μm or more and 260 μm or less.

[0027] The pressure-sensitive adhesive contains an acrylic polymer. The pressure-sensitive adhesive may contain a tackifier, a crosslinking agent, and the like in addition to the acrylic polymer. The pressure-sensitive adhesive preferably contains 60% by mass or more of an acrylic polymer.The pressure-sensitive adhesive may contain 80% by mass or less of an acrylic polymer.

[0028] The acrylic polymer is a copolymer in which at least (meth)acrylic acid and an alkyl (meth)acrylate ester are copolymerized. In this specification, the term "(meth)acrylic acid" refers to at least one of methacrylic acid and acrylic acid.

[0029] The (meth)acrylic acid alkyl ester constituting the acrylic polymer is an ester compound of (meth)acrylic acid and a monohydric alkyl alcohol having 2 to 8 carbon atoms. Examples of the monohydric alkyl alcohol having 2 to 8 carbon atoms include ethyl alcohol, butyl alcohol, and 2-ethylhexyl alcohol.

[0030] In the above acrylic polymer, the copolymerization ratio of (meth)acrylic acid and (meth)acrylic acid alkyl ester is not particularly limited, but it is preferable that the mass ratio of (meth)acrylic acid / (meth)acrylic acid alkyl ester is 3 / 97 to 12 / 88.

[0031] Examples of the acrylic polymer include (meth)acrylic acid / (meth)acrylic acid ethyl ester copolymer, (meth)acrylic acid / (meth)acrylic acid butyl ester copolymer, and (meth)acrylic acid / (meth)acrylic acid-2-ethylhexyl copolymer.

[0032] As the acrylic polymer, a copolymer of only (meth)acrylic acid and (meth)acrylic acid alkyl ester is preferable, and a (meth)acrylic acid / (meth)acrylic acid butyl ester copolymer is more preferable, in that the adhesive has better adhesion. The acrylic polymer may be in a crosslinked state with a crosslinking agent.

[0033] Examples of the tackifier resin include rosin resin, terpene resin, phenol resin, xylene resin, coumarone resin, and styrene resin. The content of the tackifier resin in the adhesive may be 50 parts by mass or less per 100 parts by mass of the acrylic polymer. The content of the tackifier resin may be, for example, 20 parts by mass or more per 100 parts by mass of the acrylic polymer. These tackifier resins may be used alone or in combination of two or more.

[0034] Examples of the crosslinking agent include an epoxy crosslinking agent, a polyfunctional isocyanate crosslinking agent, a melamine resin crosslinking agent, and a metal chelate crosslinking agent. The content of the crosslinking agent in the adhesive may be 10 parts by mass or less relative to 100 parts by mass of the acrylic polymer. The content of the crosslinking agent may be, for example, 3 parts by mass or more relative to 100 parts by mass of the acrylic polymer. These crosslinking agents may be used alone or in combination of two or more.

[0035] Since the adhesive tape 1 of the present embodiment is configured as described above, terminal peeling is suppressed. For example, as shown in FIG. 3, the adhesive tape 1 of the present embodiment is wrapped around a bundle of electric wires A to be used in a wire harness. In this case, the outermost end of the wrapped adhesive tape 1 is easily peeled off due to long-term use in a high-temperature environment. Such terminal peeling Z is suppressed in the adhesive tape 1 of the present embodiment. Note that, although there is a gap between the overlapping adhesive tapes due to wrapping in FIG. 3, in reality, there is no such gap. The mechanism by which edge peeling Z is suppressed will be explained later.

[0036] Next, one embodiment of the pressure-sensitive adhesive composition according to the present invention will be described.

[0037] The adhesive composition of the present embodiment is applied to a fiber base fabric 2 to prepare an adhesive tape 1.

[0038] The adhesive composition of the present embodiment further contains an organic solvent in addition to the above-mentioned adhesive (solid content). In other words, the adhesive composition of the present embodiment further contains an organic solvent in addition to the components contained in the above-mentioned adhesive. In other words, the pressure-sensitive adhesive composition of the present embodiment contains at least an acrylic polymer as the pressure-sensitive adhesive, and also contains at least ethyl acetate as the organic solvent.

[0039] In the adhesive composition, the amount of the organic solvent per 100 parts by mass of the adhesive is preferably 110 parts by mass or more and 200 parts by mass or less, and the amount of ethyl acetate per 100 parts by mass of the acrylic polymer is preferably 150 parts by mass or more and 270 parts by mass or less.

[0040] The organic solvent preferably contains 90% by mass or more, more preferably 95% by mass or more, of ethyl acetate. Ethyl acetate has an ester bond in the molecule, similar to the above-mentioned acrylic polymer. Therefore, the acrylic polymer is easily dissolved in ethyl acetate. The greater the amount of ethyl acetate in the organic solvent, the easier the acrylic polymer is to dissolve in the organic solvent, and the lower the viscosity of the adhesive composition of this embodiment can be. Therefore, the operation of applying the adhesive composition to the fiber base fabric 2 (described later) becomes easier.

[0041] The vapor pressure of ethyl acetate (12.5 kPa) is relatively high. The vapor pressure of ethyl acetate is higher than the vapor pressure of toluene (3.8 kPa), for example. Therefore, after the adhesive composition is applied to the fiber base fabric 2 (described later), the ethyl acetate volatilizes into the air relatively quickly.

[0042] The adhesive composition of the present embodiment can be applied to a fiber base fabric 2 to impart adhesiveness when producing an adhesive tape 1. Since the acrylic polymer has an ester bond in the molecule, similar to ethyl acetate, in the above adhesive composition, the acrylic polymer is dissolved in ethyl acetate. When the above-mentioned adhesive composition is applied to the fiber base fabric 2, the acrylic polymer and ethyl acetate are impregnated into the fiber base fabric 2 while the ethyl acetate is volatilized. As the ethyl acetate volatilizes, the viscosity of the composition increases and impregnation becomes difficult, so that the impregnation speed slows down and impregnation stops as the ethyl acetate volatilizes. Moreover, since ethyl acetate has a relatively high vapor pressure, it volatilizes relatively quickly after application, so that the acrylic polymer penetrates into the fiber base fabric 2 only to a relatively shallow portion. As described above, the contact angle of ethyl acetate with respect to a film made of the same material as the fiber base fabric 2 is preferably 13° or more. When the fiber base fabric 2 is made of such a material, the wettability of ethyl acetate with respect to the fiber base fabric 2 becomes relatively low. The lower the wettability, the less easily ethyl acetate can be impregnated into the fiber base fabric 2. This makes it possible to more reliably make the impregnation depth of the acrylic polymer shallower. In the surface layer portion of the fiber base fabric 2 into which the acrylic polymer has permeated, the acrylic polymer has permeated into the gaps between the fibers of the fiber base fabric 2. Therefore, the surface layer portion becomes harder than before impregnation by the amount of the acrylic polymer that has permeated into the gaps. The pressure-sensitive adhesive tape 1 produced after volatilization becomes harder than the fiber base fabric 2 by the amount that the surface layer portion has become harder. However, as described above, the acrylic polymer penetrates only to a relatively shallow portion of the fiber base fabric 2, resulting in a shallow impregnation depth. In other words, the thickness of the hardened surface layer portion is thin. For example, the thickness of the hardened surface layer portion can be made less than half the thickness of the fiber base fabric 2. This allows the adhesive tape 1 to maintain a relatively soft state without losing much of the softness of the fiber base fabric 2 itself. Therefore, even if the adhesive tape 1 is wound around an object such as a number of electric wires and is left for a long period of time at high temperatures, the phenomenon of the end portions peeling off due to the rigidity of the adhesive tape 1 itself can be suppressed by the softness of the tape. In other words, the end portions that are wound and attached in a curved state and are not pressed from the outside tend to maintain that state due to their softness. Therefore, peeling at the end portions can be suppressed.

[0043] Next, one embodiment of a method for producing a pressure-sensitive adhesive tape according to the present invention will be described.

[0044] The method for manufacturing the adhesive tape of this embodiment includes a composition preparation step of preparing an adhesive composition containing the above-mentioned adhesive and the above-mentioned organic solvent, an application step of applying the adhesive composition to a fiber base fabric 2, and an volatilization step of volatilizing the organic solvent contained in the applied adhesive composition. Through these steps, an adhesive tape 1 is produced in which the impregnation depth of the adhesive into the fiber base fabric 2 is less than 1 / 2 the thickness of the fiber base fabric 2, and the adhesive tape 1 has an adhesive layer 3 superimposed on one side of the fiber base fabric 2.

[0045] In the composition preparation step, the above-mentioned adhesive is mixed with an organic solvent to prepare an adhesive composition. A tackifier resin and a crosslinking agent may be added and mixed to prepare an adhesive composition. At least an acrylic polymer is used as the adhesive, and at least ethyl acetate is used as the organic solvent.

[0046] The composition preparation step allows the adhesive and tackifier resin to dissolve in the organic solvent, thereby obtaining a solution-like adhesive composition. The viscosity of the adhesive composition can be adjusted by changing the amount of the organic solvent to be blended.

[0047] In the composition preparation step, the time until the completion of evaporation in the evaporation step can be adjusted by changing the type and amount of the organic solvent. For example, by using ethyl acetate and an organic solvent having a lower vapor pressure than ethyl acetate as the organic solvent and increasing the relative amount of the latter organic solvent, the time until the completion of evaporation can be made longer.

[0048] The adhesive composition prepared in the composition preparation step is applied to the fiber base fabric 2 in the application step to impart adhesiveness to the fiber base fabric 2.

[0049] In the coating step, as the fiber base fabric 2, for example, a raw roll of the fiber base fabric 2 having a rectangular shape is used.

[0050] In the coating step, the adhesive composition prepared in the composition preparation step is coated on one side of the fiber base fabric 2. In the coating step, a general coating method such as a comma direct coating method or a comma reverse coating method can be used. The coating step is usually performed at room temperature (15 to 25°C). As a coating method, a cone-reverse coating method is preferred in that it reduces variation in the amount of adhesive applied.

[0051] In the application step, the amount of the adhesive composition applied to the fiber base fabric 2 is preferably 50 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the fiber base fabric. In addition, the adhesive composition is preferably applied so that the amount of the adhesive is 70 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the fiber base fabric. In addition, the adhesive layer 3 can be made thicker by increasing the amount of adhesive composition applied, while the adhesive layer 3 can be made thinner by decreasing the amount of adhesive composition applied.

[0052] It is preferable that the time from when the adhesive composition is applied to the fiber base fabric 2 until the volatilization step is started is as short as possible.

[0053] In the volatilization step, for example, the fiber base fabric 2 after application is left to stand for 10 minutes to 20 minutes in an environment of 90° C. to 130° C. In this way, the organic solvent can be volatilized from the applied pressure-sensitive adhesive composition, and the organic solvent can be removed.

[0054] In the volatilization step, the temperature during volatilization can be changed to adjust the depth of impregnation of the adhesive into the fiber base fabric 2. For example, by increasing the temperature during volatilization, the organic solvent (ethyl acetate) can be volatilized before the adhesive composition is deeply impregnated into the fiber base fabric 2. This makes it possible to make the depth of impregnation of the adhesive into the fiber base fabric 2 shallower.

[0055] After the volatilization step, the rectangular raw fabric 2 impregnated with the adhesive composition is wound around a core to form a roll. The roll is cut in a direction perpendicular to the axis of winding to obtain a rolled adhesive tape 1.

[0056] The adhesive tape 1 manufactured as described above is used, for example, to bundle a plurality of electric wires in a wire harness. The pressure-sensitive adhesive tape 1 is attached to an object to be adhered so that the pressure-sensitive adhesive layer 3 comes into contact with the object to be adhered. In general, the pressure-sensitive adhesive tape 1 is used by wrapping the tape around the object to be adhered several times with the pressure-sensitive adhesive layer 3 disposed on the inner side.

[0057] By applying the above-mentioned adhesive tape 1 to an adherend and then heating and humidifying, the adhesive strength can be increased by increasing the adhesion to the adherend. As described above, an adhesive tape in which the impregnation depth of the adhesive is less than 1 / 2 the thickness of the fiber base fabric has stronger adhesive strength because stringing occurs from both the adherend and the adhesive tape when peeled off from the adherend after heating and humidifying. On the other hand, an adhesive tape in which the impregnation depth of the adhesive is 1 / 2 or more the thickness of the fiber base fabric has weaker adhesive strength because stringing occurs only from the adherend when peeled off in the same manner.

[0058] The pressure-sensitive adhesive composition and pressure-sensitive adhesive tape of the present embodiment are as exemplified above, but the present invention is not limited to the pressure-sensitive adhesive composition and pressure-sensitive adhesive tape exemplified above. That is, various forms used in general pressure-sensitive adhesive compositions and pressure-sensitive adhesive tapes can be adopted within the scope that does not impair the effects of the present invention. EXAMPLES

[0059] The present invention will now be described in more detail with reference to experimental examples, but the present invention is not limited to these.

[0060] An adhesive composition was produced as follows. An adhesive tape was produced using this adhesive composition as follows.

[0061] <Raw materials for adhesive composition> Adhesive Acrylic polymer (acrylic acid / butyl acrylate copolymer) (mass ratio of acrylic acid / butyl acrylate=4.8 / 95.2) Tackifier resin (xylene-based resin) Crosslinking agents (melamine resin-based crosslinking agents and polyfunctional isocyanate-based crosslinking agents) Organic solvents Ethyl acetate

[0062] <Raw materials for adhesive tape> ·Fiber base fabric Acetate fiber woven fabric (specifically, a plain weave fabric with a warp thread thickness of 84 decitex, a weft thread thickness of 167 decitex, a warp thread density of 70 threads / 10mm, and a weft thread density of 24 threads / 10mm) Thickness 180μm The contact angle of ethyl acetate on the acetate film was 16.7°. Contact angle measurement conditions: ethyl acetate temperature 23°C, drop amount 4μL, measurement environment 24°C, contact angle measured from image of droplet on acetate film 0.1 seconds after drop

[0063] Example 1 According to the formulation shown in Table 1, the components were mixed at 23° C. to prepare a pressure-sensitive adhesive composition. The prepared adhesive composition was then coated on one side of a fiber base fabric by cone reverse coating, and the resulting mixture was left at 100° C. for 15 minutes to volatilize the ethyl acetate, thereby producing an adhesive tape. The adhesive impregnation depth was measured using a microscope on a cross section of the adhesive tape cut in the thickness direction. The result was that the adhesive impregnation depth was 4 / 10 of the thickness of the fiber base fabric. The thickness of the adhesive layer was 35 μm.

[0064] Example 2 Using the blending compositions shown in Table 1, pressure-sensitive adhesive compositions and pressure-sensitive adhesive tapes were produced in the same manner as in Example 1. In the adhesive tape, the impregnation depth of the adhesive was 3 / 10 of the thickness of the fiber base fabric, and the thickness of the adhesive layer was 40 μm.

[0065] (Comparative Example) Using the blending compositions shown in Table 1, pressure-sensitive adhesive compositions and pressure-sensitive adhesive tapes were produced in the same manner as in Examples 1 and 2. In the adhesive tape, the impregnation depth of the adhesive was the thickness of the fiber base fabric (10 / 10), and the thickness of the adhesive layer was 37 μm.

[0066] Table 1 shows the blending compositions for producing the pressure-sensitive adhesive compositions and pressure-sensitive adhesive tapes of the examples and comparative examples.

[0067] [Table 1]

[0068] The adhesive tapes produced in the Examples and Comparative Examples were evaluated for edge peel resistance as described below. The results of such evaluation are shown in Table 2.

[0069] <End peeling resistance> A 10mm wide adhesive tape was wrapped around a 2mm diameter metal rod three times with a load of 1N. After cutting with scissors, the end of the tape was pressed with a load of 1N. After leaving it at 23℃ for 7 days, the length of edge peeling was measured with a steel ruler. Three samples were measured, and the minimum and maximum values ​​were calculated and averaged. This numerical range was used as an index of edge peeling resistance.

[0070] [Table 2]

[0071] As can be seen from the above evaluation results, edge peeling was suppressed in the pressure-sensitive adhesive tapes of the Examples, compared to the pressure-sensitive adhesive tapes of the Comparative Examples. [Industrial Applicability]

[0072] The pressure-sensitive adhesive composition of the present invention is preferably used for producing a pressure-sensitive adhesive tape that is suppressed from peeling at the edge, for example. The pressure-sensitive adhesive tape of the present invention is preferably used for bundling a plurality of electric wires, for example. [Explanation of symbols]

[0073] 1: adhesive tape, 2: fiber base fabric; 3: adhesive; A: Electric wire, Z: Terminal peeling.

Claims

[Claim 1] An adhesive tape comprising a fiber base fabric and an adhesive layer overlapping one surface of the fiber base fabric, the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive containing an acrylic polymer, In the fiber base fabric, a surface layer portion overlapping the pressure-sensitive adhesive layer is impregnated with the pressure-sensitive adhesive, The impregnation depth of the adhesive into the fiber base fabric is less than 1 / 2 of the thickness of the fiber base fabric, The material of the fiber base fabric is such that a contact angle of ethyl acetate with a film formed from the material is 13° or more.

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