JP2018058661A - CNF-containing body, tubular body, and method for producing tubular body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CNF-containing body capable of obtaining a high-strength tubular body or the like by using a sheet-like member containing CNF.SOLUTION: A CNF-containing body at least partially comprising a laminated structure formed by laminating and integrating sheet-like members 12 containing CNF.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a CNF-containing body containing CNF, a tubular body that can be used for a core and the like, and a method for producing the tubular body.

  In recent years, research and development relating to the use of cellulose nanofibers (hereinafter sometimes referred to as “CNF”) as materials excellent in strength, gas barrier properties, and the like have been promoted. CNF is obtained by unraveling plant fibers obtained from wood or the like and making them finer to the nano-order. Since CNF is derived from plant fibers, it has a small environmental load due to production and disposal. In addition, CNF is light and strong, hardly thermally expands, has excellent gas barrier properties, and is expected to be used in various applications.

  Patent Document 1 discloses an example of a method for producing a CNF-containing sheet (cellulose nanofiber sheet). Patent Document 2 discloses a technique for controlling the orientation of CNF contained in a sheet. As a member containing CNF, a sheet-like member that is advantageous in a drying process at the time of manufacture is generally used.

  On the other hand, conventionally, tubular bodies and plate-like bodies formed of paper or the like (hereinafter sometimes collectively referred to as “tubular bodies”) have been widely used for various applications. For example, Patent Document 3 discloses a core paper tube that can be used as a core for various sheets. Such a paper tube is advantageous in that it is more economical and easier to process than a tubular body formed of other materials, and that recycled paper can be used.

  In addition, about a tubular body etc., low weight and high intensity | strength are often calculated | required. For example, a tubular body for a winding core is desired to be lightweight from the viewpoint of ease of handling and the like, but also needs to have a certain level of strength so that it can withstand the process of winding a film or sheet. In addition, when used as a structural member such as a car body or a building material, both low weight and high strength are emphasized in order to reduce the weight and improve the strength of the finished product.

JP2015-044892A JP-A-2015-040358 JP 2011-241064 A

  If a tubular body having high strength can be obtained by utilizing the characteristics of CNF, it is expected that both low weight and high strength can be achieved at a high level. However, the sheet-like member itself containing CNF is formed very thin in consideration of the ease of performing the drying process described above. Therefore, even if an attempt is made to use the sheet-like member for the purpose of obtaining a high-strength tubular body or the like, it is difficult to obtain a desired strength simply by sticking the sheet-like member to the tubular body or the like.

  In view of the above-described problems, the present invention provides a CNF-containing body that can obtain a tubular body having high strength using a sheet-like member containing CNF, a tubular body that is one form thereof, and a tubular body. The purpose is to provide a manufacturing method.

  The CNF-containing body according to the present invention has at least a part of a laminated structure in which sheet-like members containing CNF are laminated and integrated. According to this structure, it becomes possible to obtain a high strength tubular body or the like using a sheet-like member containing CNF. Here, the CNF-containing body is not limited to a part having a laminated structure in which sheet-like members are laminated and integrated, and is a concept including the whole having the laminated structure.

  The tubular body according to the present invention is a tubular body formed as a CNF-containing body having the above-described configuration. The sheet-like member is wound and integrated so as to be laminated in the tubular radial direction. The configuration. According to this configuration, a high strength tubular body can be obtained.

  More specifically, the sheet-like member is formed so that each of the contained CNFs is oriented in a predetermined direction, and the orientation direction substantially coincides with the tubular axial direction. It is good also as a structure wound. According to this configuration, the strength of the tubular body can be further increased, and generation of axial wrinkles in the tubular body can be suppressed as much as possible. Here, “winding so that the direction of the orientation substantially matches the axial direction of the tube” means that the entire sheet-like member is wound so as to substantially match the axial direction. However, when only a part of the sheet-like member is wound so as to substantially coincide with the axial direction, or when a plurality of sheet-like members are successively wound, only some of the sheet-like members are It is a concept including a form wound so as to substantially coincide with the axial direction.

  More specifically, the above configuration may be a configuration in which the sheet-like member is wound around the outer peripheral surface of the tubular member so as to be laminated and reinforced. According to this configuration, it is possible to obtain an effective reinforcing effect for the tubular member.

  More specifically, the tubular member, the sheet-like member, and the adjacent layers in the sheet-like member may be fixed by an adhesive, respectively. More specifically, the tubular member may be a paper tube, and may be used as a winding core for winding the wound object.

  Moreover, the 1st manufacturing method which concerns on this invention is a manufacturing method of the tubular body of the said structure, Comprising: The process of extending the said sheet-like member, The process of apply | coating an adhesive agent to the said sheet-like member, The said tubular member And winding the sheet-like member coated with the adhesive around the outer peripheral surface of the sheet. According to this method, the sheet-like member can be stretched and the adhesive can be easily applied.

  A second manufacturing method according to the present invention is a method for manufacturing a tubular body having the above-described configuration, in which a plurality of the sheet-like members coated with an adhesive are wound around the outer peripheral surface of the tubular member in order. And a drying step of drying the adhesive, and after winding one sheet-like member around the tubular member, before wrapping all the sheet-like members around the tubular member, A method in which at least one drying step is performed. According to this method, it becomes possible to dry the adhesive more reliably and easily than when the adhesive is dried after, for example, all the sheet-like members are wound around the tubular member.

  According to the CNF-containing body according to the present invention, it is possible to obtain a high-strength tubular body using a sheet-like member containing CNF.

It is an external view near the edge part of the tubular body for cores concerning this embodiment. It is a typical block diagram of the edge part of the tubular body for winding cores concerning this embodiment. It is a conceptual diagram of the manufacturing apparatus of the tubular body for cores concerning this embodiment. It is a flowchart of the manufacturing method using the said manufacturing apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. However, the content of the present invention is not limited to the embodiment.

1. Configuration of Tubular Body for Winding Core FIG. 1 is an external view of the vicinity of the end of the tubular body for core 1 according to the present embodiment. FIG. 2 is a schematic configuration diagram of an end portion (portion indicated by α in FIG. 1) of the core body 1 for a core. The tubular core body 1 (one form of the CNF-containing body according to the present invention) is wound around the outer peripheral surface of the tubular member 11 so that the sheet-like member 12 is laminated in several tens or more layers and is reinforced. Yes.

  The tubular member 11, the sheet-like member 12, and adjacent layers in the sheet-like member 12 are each firmly fixed by an adhesive. The multi-layered sheet-like member 12 forms the reinforcing portion 1a integrated by such adhesive fixing, and can effectively reinforce the tubular member 11 by utilizing the characteristics of CNF.

  The tubular member 11 is a conventional general paper tube or a similar one, and is used as a core around which the sheet-like member 12 is wound. The tubular member 11 may be a conventional core paper tube. In addition, although the tubular member formed with materials other than paper may be applied as the tubular member 11, if a paper tube is applied, the adhesive fixing with the sheet-like member 12 using an adhesive is easy, This is also advantageous in terms of economy and workability. Moreover, although the tubular member in this embodiment is cylindrical shape, as long as a sheet-like member can be wound, tubular members other than cylindrical shape may be employ | adopted.

  The sheet-like member 12 is a thin sheet-like member containing a large amount of CNF. Since the sheet-like member 12 contains CNF, the sheet-like member 12 is light and high in strength, hardly thermally expands, and has excellent gas barrier properties. As the sheet-like member 12, a capacitor paper containing CNF may be employed.

  The sheet-like member 12 is formed so that each CNF contained in the sheet-like member 12 is oriented in a predetermined direction. In addition, since the formation method itself of the sheet-like member which orientated CNF in this way is well-known, the detailed description is abbreviate | omitted here.

2. Next, an example of a method for producing the core tubular body 1 will be described with reference to FIGS. 3 and 4. FIG. 3 shows a schematic block diagram of an apparatus for manufacturing the tubular core body 1. In the following description, the front and rear and left and right directions (directions orthogonal to each other) are as shown in FIG. FIG. 4 shows a flowchart (flow of each process) of a manufacturing method using the apparatus shown in FIG.

  Although not shown in FIG. 3, the manufacturing apparatus includes a mechanism that automatically performs a part or all of each process (for example, a mechanism that automatically conveys the sheet-like member 12, a mechanism that moves the tubular member 11, etc.) ) May be provided. Moreover, you may make it perform a part or all of each process manually.

  3 includes a roll stand 21, a cutting device 22, a stretching device 23, an adhesive application device 24, a winding device 25, and a drying device 26. On the roll stand 21, the original sheet wound in a roll shape that is the base of the sheet-like member 12 is rotatably supported, and the tubular member 11 is set at a position on the left side of the winding device 25.

  The orientation direction of CNF contained in the sheet original fabric coincides with the direction in which the roll of the sheet original fabric is wound (that is, the circumferential direction of the roll shape). The roll-shaped central axis extends in the left-right direction, and the sheet material can be pulled forward in order from the end.

  The original sheet supported by the roll stand 21 is drawn forward by an amount corresponding to the axial length of the tubular member 11 and conveyed toward the stretching device 23. Moreover, the sheet | seat original fabric pulled out in this way is cut by the cutting apparatus 22 arrange | positioned ahead of the roll stand 21 (refer S1 of FIG. 4). Thereby, the sheet-like member 12 for one sheet is obtained.

  The stretching device 23 is formed so that the sheet-like member 12 obtained in this way can be pulled in a direction in which the sheet-like member 12 is expanded with an appropriate force. In this way, the stretching device 23 pulls and stretches the sheet-like member 12 (see S2 in FIG. 4), and makes the sheet-like member 12 in a more appropriate state. The stretching device 23 is not limited to a device that pulls and stretches the sheet-like member 12, and may be a device that stretches the sheet-like member 12 by other methods. The stretching device 23 may be a device that prompts the sheet-like member 12 to stretch. The “step of stretching the sheet-like member” in the present invention is a concept including a step of urging the sheet-like member to stretch in addition to the step of actively stretching the sheet-like member.

  The sheet-like member 12 stretched as described above is conveyed to an adhesive application device 24 arranged further forward. The adhesive application device 24 applies the adhesive to the entire surface of the sheet-like member 12 received from the stretching device 23. In addition, since the sheet-like member 12 is appropriately stretched by the stretching device 23, it is easy to apply the adhesive appropriately.

  The adhesive application device 24 includes, for example, a pair of upper and lower rollers (roller pairs) that rotate so as to feed the sheet-like member 12 forward from both sides, and when the roller pair feeds the sheet-like member 12 therebetween. In addition, an adhesive is applied to the sheet-like member 12. However, various configurations may be adopted as the configuration of the adhesive application device 24 as long as the adhesive can be appropriately applied to the sheet-like member 12.

  Normally, the adhesive is applied only to one side of the sheet-like member 12 (the inner side when wound on the tubular member 11), but it may be applied to both sides as required. As an adhesive to be applied to the sheet-like member 12, an adhesive mainly composed of a vinyl acetate resin can be used. However, an adhesive containing CNF (for example, CNF (registered trademark “Serisch” manufactured by Daicel Finechem Co., Ltd.). By using the adhesive containing “)”, the strength or heat resistance is expected to be improved.

  The sheet-like member 12 sent out from the adhesive application device 24 is set in the winding device 25 in a flat state that expands in the front-rear and left-right directions. On the other hand, the tubular member 11 set in the winding device 25 is disposed in the vicinity of the left edge of the flat sheet-like member 12. The orientation direction of CNF contained in the sheet-like member 12 and the axial direction (extending direction) of the tubular member 11 are the same in the front-rear direction.

  The tubular member 11 set in this way is moved so as to roll to the right. At this time, the flat sheet-like member 12 is wound around the outer peripheral surface of the tubular member 11 in order from the left edge (see S4 in FIG. 4). That is, the sheet-like member 12 is completely wound around the tubular member 11 as a core. The number of windings when the sheet-like member 12 for one sheet is wound around the tubular member 11 is determined by the width (dimension in the left-right direction) of the sheet-like member 12. The number of windings is not particularly limited. However, if the amount is too small, the production efficiency is deteriorated. If the amount is too large, the adhesive is difficult to dry. Is preferred.

  Thus, after winding of the sheet-like member 12 for one sheet (winding of the sheet-like member 12 for one time) is performed, the tubular member 11 is left to stand for a predetermined time and bonded to the sheet-like member 12. The agent is dried (see S5 in FIG. 4). At this time, the tubular member 11 may be transferred to the drying device 26. The drying device 26 is installed adjacent to the right side of the winding device 25, and the tubular member 11 that has moved to the right in the winding device 25 can be smoothly guided into the drying device 26. A heater is disposed in the drying device 26, and the adhesive applied to the sheet-like member 12 can be efficiently dried.

  After the drying, the tubular member 11 is set again at the left position of the winding device 25 (see S6 in FIG. 4). On the other hand, a new sheet-like member 12 is supplied to the winding device 25 from the original sheet set on the roll stand 21. The sheet-like member 12 is also coated with an adhesive through the above-described steps (S1 to S3 in FIG. 4), and is set on the winding device 25 in a flat state. In this state, the tubular member 11 is moved so as to roll to the right again, and as a result, the sheet-like member 12 is further wound around the tubular member 11 (see S4 in FIG. 4). Thereafter, the drying step described above is performed again so as to dry the adhesive applied to the sheet-like member 12 wound this time (see S5 in FIG. 4).

  The series of steps described above (S1 to S6 in FIG. 4) is repeated until the number of times the sheet-like member 12 is wound around the tubular member 11 reaches a specified number (see S7 in FIG. 4). The specified number of times is set to an appropriate number in advance so that a necessary reinforcing effect for the tubular member 11 can be obtained. After the drying step (see S5 in FIG. 4), if the number of windings of the sheet-like member 12 has reached the specified number (in the case of “YES” in S7 in FIG. 4), the winding core tubular body 1 Manufacturing is complete.

  By the manufacturing process described above, the tubular core body 1 for winding is reinforced by being wound so that the sheet-like member 12 is laminated on the outer peripheral surface of the tubular member 11. Further, if the sheet-like member 12 is not sufficiently dried, it is difficult to obtain a reinforcing effect. However, in the present embodiment, consideration is given to sufficiently drying the sheet-like member 12 to obtain an intended reinforcing effect.

  In this embodiment, since a drying process is performed every time the sheet-like member 12 is wound, the sheet-like member 12 can be dried as reliably and easily as possible. Instead of performing the drying process every time one sheet-like member 12 is wound, the drying process may be performed each time a plurality of sheet-like members 12 are wound, for example, within a range that does not prevent sufficient drying. good. If one sheet-like member 12 is wound around the tubular member 11 and before all the sheet-like members 12 are wound around the tubular member 11, at least one drying step is performed. The sheet-like member 12 can be more reliably and easily dried as compared with the case where the drying process is performed after all the winding of the like-like member 12 is performed.

  Further, the sheet-like member 12 is wound around the tubular member 11 so that the orientation direction of CNF coincides with the axial direction of the tubular member 11. The sheet-like member 12 containing CNF has a high tensile elastic modulus and tensile strength in the orientation direction of CNF (see Table 1 and its description to be described later). Thus, the sheet-like member 12 is wound efficiently in this way. It is possible to obtain a tubular core body 1 with a higher bending elastic modulus and higher bending strength. From the viewpoint of the reinforcing effect, it is preferable to wind all the sheet-like members 12 in this way as in the present embodiment, but only a part of the sheet-like members 12 may be wound in this way.

  Further, in the sheet-like member 12, for example, when the applied adhesive is dried, wrinkles hardly occur in the direction in which the contained CNF extends, that is, the orientation direction of CNF. In this embodiment, since the orientation direction of CNF coincides with the axial direction of the tubular member 11, it is possible to suppress axial wrinkles that have a relatively large effect on the quality of the tubular core body 1 and the like as much as possible. However, the present invention is not limited to this form, and the sheet-like member 12 may be wound so that the orientation direction of CNF is different from the axial direction of the tubular member 11.

3. Evaluation test by each example (1) Evaluation of sheet-like member As a specific example of the sheet-like member 12 containing CNF, three types of CNF-containing papers A to C are given, and the results of comparing the respective characteristics with high-quality paper are as follows. Table 1 shows. In addition, MD direction in Table 1 is a direction wound in a roll shape in the state of a sheet original fabric (in the case of CNF-containing paper, the orientation direction of CNF), and the CD direction is a direction orthogonal to the MD direction. The strength ratio indicates the ratio of the tensile modulus or tensile strength to the value of fine paper.

  From the viewpoint of difficulty in deformation due to the reinforcing effect and improvement in strength, the sheet-like member preferably has a higher tensile elastic modulus and tensile strength. As shown in Table 1, all the CNF-containing papers have generally good characteristics as compared with the high-quality paper. In particular, the CNF-containing paper A having a higher density than others has very excellent characteristics.

(2) Evaluation of core for tubular core A tubular tubular body 1 (standard inner diameter 12 mm, standard outer diameter 14.6 mm) using the above-described CNF-containing papers A to C as sheet-like members 21 is referred to as Examples 1 to 3, respectively. Table 2 shows the results of the bending test performed on each example. A tubular core for a core to which high-quality paper is applied instead of the sheet-like member 21 is used as a comparative example, and the results for the comparative example are also shown. The strength ratio indicates the ratio of the flexural modulus or flexural strength to the value of the comparative example. In any of the examples, the tubular member 11 (core material) around which the sheet-like member is wound has a cylindrical shape with an inner diameter of about 12 mm and a thickness of about 0.5 mm. As a condition of the bending test, the span length was 80 mm, and the center of the sample was pressed at a speed of 5 mm / min with a bending wedge jig.

  As shown in Table 2, in all examples, better results than the comparative example were obtained for both the flexural modulus and the bending strength. In particular, for Example 1 employing CNF-containing paper A as the sheet-like member 12, the bending elastic modulus was 6.6 times and the bending strength 2.4 times that of the comparative example, and very excellent results could be obtained. .

In addition, a relatively small diameter core tubular body 1 (standard inner diameter 6 mm, standard outer diameter 8.6 mm) using CNF-containing papers A and B as a sheet-like member 12 is referred to as Examples 4 and 5, respectively. Table 3 shows the results of a similar bending test performed on the examples. In addition, the thickness (standard thickness 0.5 mm) of the tubular member 11 and the thickness (standard thickness 0.85 mm) of the reinforcing portion X (laminated portion of the sheet-like member 12) are common in all the examples. As shown in Table 3, when the diameter of the core for tubular core 1 is reduced without changing the thickness, the flexural modulus and the bending strength are greatly improved.

  In addition to the above-mentioned evaluation test results, when the adhesion between the layers of the sheet-like member is not sufficient (when using an adhesive that is difficult to obtain a good adhesion state), compared to the case where the adhesion is sufficient, The test result that bending strength was inferior was obtained. From this result, it can be said that it is desirable to use an adhesive (for example, a vinyl acetate adhesive) that can satisfactorily bond sheet-like members as an adhesive used for adhesion between layers.

4). Summary As described above, the core tubular body 1 according to this embodiment is reinforced by being wound around the outer peripheral surface of the tubular member 11 so that the sheet-like member 12 containing CNF is laminated. Therefore, according to the core body 1 for a core, a reinforcing effect is effectively obtained using the sheet-like member 12.

  A tubular core body 1 formed of a paper tubular member 11 (core material) and a sheet-like member 12 is used as a core component (FRP core) formed of FRP (Fiber Reinforced Plastics). Compared to the environment, it is also excellent in recyclability, and since glass fibers and the like are not exposed, the surface smoothness is also excellent. Furthermore, the tubular body for core 1 according to the present embodiment has a strength equal to or higher than that of the FRP core due to the reinforcing effect using the sheet-like member 12.

  In addition, the tubular body which concerns on this invention is not restricted to the cores like this embodiment, It can utilize for various uses. In particular, the tubular body is suitable for applications that take advantage of the characteristics of CNF (because it is derived from plant fibers, has a low environmental impact associated with production and disposal, is light and strong, is difficult to thermally expand, and is excellent in gas barrier properties). is there. In addition, there is room for application to a use that is difficult to apply to a tubular body containing glass fiber or the like if it is a tubular body according to the present invention.

  For example, the tubular body according to the present invention is expected to be applied to (A) automobiles and bicycles, (B) home appliances and furniture, (C) building materials, and (D) sports equipment. With regard to the above (A), if the tubular body according to the present invention is used for a frame or a rim, the weight can be reduced as compared to a metal material such as aluminum or titanium, and fuel efficiency and driving performance can be improved. Regarding the above (B), the tubular body according to the present invention is a housing for acoustic home appliances using the acoustic characteristics of cellulose material, a cushioning material for large home appliances such as an air conditioner using buffer characteristics, or a natural material using the raw material as it is. It can be expected to be applied to oriented furniture parts and supports. With regard to the above (C), the tubular body according to the present invention can be expected to be applied to handrails that make use of the feel of paper that is not cold when touched, or to a core material that uses moisture absorption and desorption. Regarding the above (D), the tubular body according to the present invention is designed so that characteristics such as high strength, light weight, shock absorption, and toughness are suitable for the content of the game, and metal such as golf clubs, baseball bats, fishing rods, and carbon It can be applied as a substitute member of a fiber member.

  In addition, about the method of winding the sheet-like member containing CNF, in the above-described embodiment, a method (flat winding) in which the winding position does not change in the axial direction is adopted, but winding is performed while shifting the winding position in the axial direction. You may employ | adopt the method (namely, spiral winding wound around helically).

  Moreover, as a form of the tubular body which concerns on embodiment of this invention, the sheet-like member which does not have a tubular member other than the form which wound so that the sheet-like member containing CNF might be laminated | stacked and reinforced the tubular member The form comprised only by this is also mentioned. The tubular body of this form is formed by winding a sheet-like member coated with an adhesive around a cylindrical or columnar core so as to be laminated in the radial direction, and integrating the sheet-like member into a cylindrical shape. It is obtained by extracting the core from the laminate. In this embodiment as well, any of the above-described flat winding and spiral winding may be adopted as a method of winding the sheet-like member.

  Note that the CNF-containing body according to the present invention only needs to have at least a part of the laminated structure in which the sheet-like members containing CNF are laminated and integrated. With this configuration, the sheet-like member containing CNF is provided. It is possible to obtain a tubular body having high strength by using it. Therefore, as embodiment of this invention, the form used as the plate-shaped body other than the form which is a tubular body mentioned above can also be mentioned. In order to obtain a CNF-containing body that is a plate-like body, the sheet-like members may be stacked and integrated so as to be sequentially stacked. The CNF-containing body according to the present invention can be formed into various shapes by changing the laminated form of the sheet-like member.

  Although the embodiment of the present invention has been described above, the configuration of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. That is, the above-described embodiment is an example in all respects, and should be considered as not restrictive. The technical scope of the present invention is shown not by the above description of the embodiment but by the scope of the claims, and is understood to include all modifications within the meaning and scope equivalent to the scope of the claims. Should.

  The present invention can be used as a core for winding a wound object as an example.

DESCRIPTION OF SYMBOLS 1 Tubular body for winding cores 1a Reinforcement part 11 Tubular member 12 Sheet-like member 12a Original sheet 21 Roll stand 22 Cutting device 23 Stretching device 24 Adhesive application device 24a Upstream roller pair 24b Downstream roller pair 25 Winding device 26 Drying device 26a heater

Claims (8)

  A CNF-containing body comprising at least a part of a laminated structure in which sheet-like members containing CNF are laminated and integrated. A tubular body formed into a tubular shape as the CNF-containing body according to claim 1,
The tubular body, wherein the sheet-like member is wound and integrated so as to be laminated in the tubular radial direction. The sheet-like member is
Each of the contained CNFs is formed so as to be oriented in a predetermined direction,
The tubular body according to claim 2, wherein the tubular body is wound so that a direction of the orientation substantially coincides with an axial direction of the tubular.   The tubular body according to claim 2 or 3, wherein the sheet-like member is wound around the outer peripheral surface of the tubular member so as to be laminated and reinforced.   The tubular body according to claim 4, wherein the tubular member, the sheet-like member, and adjacent layers in the sheet-like member are each fixed by an adhesive. The tubular member is a paper tube;
The tubular body according to claim 4 or 5, wherein the tubular body is used as a winding core for winding an object to be wound. A method for producing a tubular body according to any one of claims 4 to 6,
Extending the sheet-like member;
Applying an adhesive to the sheet-like member;
Winding the sheet-like member coated with the adhesive around the outer peripheral surface of the tubular member. A method for producing a tubular body according to any one of claims 4 to 6,
A winding step of sequentially winding a plurality of the sheet-like members coated with an adhesive on the outer peripheral surface of the tubular member;
A drying step of drying the adhesive,
The drying step is performed at least once after one sheet-like member is wound around the tubular member and before all the sheet-like members are wound around the tubular member. Production method.