Adhesive products, such as adhesive sheets, adhesive films and adhesive tapes, are used in a wide variety of applications. As adhesives of an adhesive layer of the adhesive products, conventionally, solution-type adhesives in which a rubber or an acrylic polymer is dissolved in a solvent have been frequently used. Recently, from the viewpoints such as the reduction in VOC emission amount and the need to improve the workability at the adhesive production site, it has been studied to replace these solution-type adhesives with hot-melt adhesives. Patent literature 1, for example, studies hot-melt adhesives in which an acrylic block copolymer is used as a base material. Patent literature 2 studies articles having a hot-melt adhesive layer containing an acrylic block copolymer. Patent literature 3 studies adhesives that contain a branched acrylic block copolymer and are useable also as hot-melt adhesives. Patent literature 4 studies reactive hot-melt adhesives containing an acrylic block copolymer which are for example aimed at having improved properties.
When an adhesive product (e.g., adhesive sheet, adhesive film) having a hot-melt adhesive layer adheres to an adherend, the adhesive product in some cases needs to be easily re-attachable, for example, in order to be positioned accurately. To make the adhesive product easily re-attachable, it would be necessary that the adhesive layer has a low tack. And yet, in a hot-melt adhesive containing an acrylic polymer, the adhesive layer having a lower tack would have insufficient adhesive force to an adherend. Thus, it has been difficult for both a low tack and a high adhesive force to be achieved. Meanwhile, when adhesive sheets (films) are transported to the place they will be used, it has been common for the sheet (film) to be wound around a roll and for the rolled sheet (film) to be transported in view of facilitating the transportation. At this time, a protective film layer is provided on an adhesive layer disposed on a base material, but will be a waste once the adhesive product is used. If it is possible for the rolled adhesive sheet (film) with no protective film layers to be transported, this would be desirable. And yet, since conventional acrylic polymer-containing hot-melt adhesives have a relatively high tack, providing no protective film layers can cause the adhesive layer to adhere to the back side of the base material during the transportation, making the use of an adhesive product impossible.