Manufacturing method of body adhesive sheet

Abstract

To suppress a thickness deviation of a gel layer at the front and rear of a push-in protrusion in a rotation direction generated by continuous type push-in using a roll.SOLUTION: A method includes a coating step for forming a laminate by feeding a long supporter sheet and separator, and by coating the top of the supporter sheet / separator or the gap therebetween with a viscoelastic material, a die pressing step of pushing in a viscoelastic laminate layer of the laminate from the side of the supporter sheet or separator to divide them, and a die-punching step of cutting the laminate in each region to punch a sheet to be pasted on a body. In the die-punching step, the viscoelastic layer is die-punched by rotating a die-punching roll which has a plurality of dies including push-in protrusions and pocket parts to be partitioned in a roll peripheral part, makes a difference in the pocket depth in a normal direction at the center of the front and rear push-in protrusions in the roll peripheral direction of each pocket part, has a pocket deepest part in a normal upstream, and keeps a pocket depth shallower than on the upstream side in a normal downstream, with the pocket bottom face constituted of gradual reduction or constant, or of combination in a difference from the roll outer periphery in a downstream direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a body adhesive sheet. [Background technology]

[0002] Conventionally, body adhesive sheets have been known that include a viscoelastic layer that adheres to and conforms to the body surface. Examples of the viscoelastic layer include a gel layer (hereinafter referred to as a hydrogel layer or simply a gel layer) that retains moisture and other substances within a crosslinked polymer structure, and some may further contain cosmetic ingredients such as moisturizers or medicinal ingredients. Such gel layers have adhesiveness, flexibility, and elasticity that allow them to adhere easily to the skin surface. Known methods for producing such body application sheets include partially pressing (pushing) and cutting a planar region of a long strip-shaped laminate having a viscoelastic layer such as a gel layer sandwiched between sheets to obtain a gel sheet of the desired shape and size (see, for example, Patent Documents 1 to 3). The long strip-shaped laminate is pressed mainly along the width direction (CD, cross direction) perpendicular to the machine direction (MD, machine direction) and divided into multiple pieces in the machine direction. In some cases, it is further pressed along the machine direction and divided into multiple pieces in the width direction as well. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-201703 [Patent Document 2] Japanese Patent Application Publication No. 02-24093 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-71570 Summary of the Invention [Problem to be solved by the invention]

[0004] Due to its viscoelasticity, the pressed (pressed) viscoelastic layer tends to move to the edge of the body-applied sheet product, where the gel layer tends to become unevenly thick. One method for this pressing process involves stopping the conveying line and pressing the laminate vertically from above. Pressing the laminate vertically tends to make the uneven thickness uniform on both sides of the pressed area. However, this requires intermittent processing, which reduces the production efficiency of the line. In this regard, Patent Document 1 proposes a manufacturing method using a processing line in which the press device moves in accordance with the sheet conveyance while pressing vertically. Even with this method, continuous pressing is required for the required time per press, leaving room for improvement in the production efficiency of body-applied sheets. In contrast, from the perspective of improving productivity, it is desirable to perform continuous pressing using a rotary roll (e.g., Patent Documents 2 and 3). However, in this case, the size of the uneven thickness of the gel layer varies before and after the convex part of the pressing roll in the direction of roll rotation (thickness difference, i.e., thickness difference occurs), which can cause local thickness differences between the left and right edges (or upper and lower edges) of the body-applied sheet product, resulting in a poor appearance. This occurs because, when the roll rotates in the same direction as the laminate transport direction, the pressing convex part penetrates the laminate transported along the line from a corner, and the amount of penetration increases with rotation, causing more of the gel layer to escape upstream than downstream. This thickness difference increases with the basis weight of the gel layer and becomes more pronounced with higher gel viscosity. Large thickness differences cause differences in rigidity at the edges of the body-applied sheet product, making the edge with higher rigidity more likely to lift off from the skin surface when applied to a curved surface of the skin (e.g., around the knees) and peel off. Furthermore, when multiple sheets of body-applied sheet products are stacked, one side becomes thicker. When gravity or other forces are applied to them, the thicker portions may be locally pressed, causing the gel to protrude from the edge of the sheet at the thickness deviation. In this regard, the manufacturing method described in Patent Document 3 proposes a smoothing process separate from the embossing process. Specifically, it describes applying even pressure using the flat surface of the roll other than the convex portion. However, this document does not address the issue of thickness deviations in the viscoelastic layer before and after the convex portion mentioned above, or what smoothing method is effective in addressing this issue. Patent Document 2 also fails to address this issue.

[0005] In view of the above, the present invention relates to a method for manufacturing a body adhesive sheet that can suppress the difference in thickness of the viscoelastic layer before and after the pressing convex portion in the roll rotation direction that occurs when a roll is continuously pressed. [Means for solving the problem]

[0006] The present invention includes a coating step of feeding out a long strip-shaped support sheet and a long strip-shaped separator, and continuously applying a viscoelastic material onto the support sheet or the separator, or between the support sheet and the separator, along the longitudinal direction to form a sheet-shaped viscoelastic layer, thereby forming a laminate of the support sheet, the viscoelastic layer, and the separator; an embossing step of pressing the sheet-shaped viscoelastic layer into a planar region of the laminate from the side of the support sheet or the separator, dividing the viscoelastic layer into a plurality of pieces of desired size and arranging them spaced apart from one another; and a die-cutting step of cutting the laminate at each pressed region to form a body application sheet, wherein in the embossing step, pressing protrusions and pressing protrusions are formed on the peripheral surface of the roll. and a pocket portion partitioned by a portion adjacent to the roll circumferential surface, the pocket depth in the direction normal to the roll circumferential surface being different with respect to the normal to the roll circumferential surface, based on a normal at the center between the center positions of the front and rear press-in protrusions in the roll circumferential surface direction, the deepest part of the pocket portion being on the upstream side of the reference normal in the roll rotation direction, the pocket depth being shallower on the downstream side of the reference normal in the roll rotation direction than on the upstream side, and the difference from the roll outer periphery in the normal direction with the pocket bottom surface gradually decreasing or keeping the difference from the roll outer periphery constant, or a combination of the gradual decrease and the constant difference, toward the downstream side, to emboss the viscoelastic layer. [Effects of the Invention]

[0007] According to the method for producing a body patch sheet of the present invention, it is possible to suppress the thickness deviation of the viscoelastic layer before and after the pressing protrusions in the roll rotation direction, which occurs when a roll is continuously pressed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a process explanatory diagram schematically illustrating a main part of a preferred embodiment of a method for producing a body patch sheet of the present invention. [Figure 2]FIG. 2 is a plan view showing an example of an embossing roll used in the present invention. [Figure 3] 1A to 1C are explanatory views showing a state in which a laminate is subjected to an embossing step and a die-cutting step in sequence. [Figure 4] 4 is an enlarged cross-sectional view of the embossing roll shown in FIG. 2 taken along line IV-IV. [Figure 5] FIG. 5 is an enlarged cross-sectional view of the mold including the pressing convex portions and pocket portions of the embossing roll shown in FIG. 4. [Figure 6] FIG. 3 is a plan view schematically showing a state in which a laminate has been pressed by the embossing roll shown in FIG. 2, together with the extrusion direction of a water-containing gel layer, which is a viscoelastic layer. [Figure 7] 1(A) to 1(D) are explanatory diagrams showing, in order, a schematic illustration of the extrusion state of the water-containing gel layer as the rotating pushing convex part is gradually brought into contact with the transported laminate. [Figure 8] 3A is a cross-sectional view schematically showing a state in which the hydrogel layer of the laminate is extruded by the pressing convex portion of the embossing roll shown in FIG. 2, and FIG. 3B is an enlarged cross-sectional view showing the pressing convex portion and its surroundings at the position where the embossing roll shown in FIG. 3A presses the laminate. [Figure 9] FIG. 8 is a cross-sectional view schematically showing a state in which the embossing roll is rotated from the state shown in FIG. 8(A), the laminate is transported, and the extruded hydrogel layer is pressed by the bottom surface of the pocket of the embossing roll to level the thickness. [Figure 10] FIG. 10 is a cross-sectional view schematically showing a state in which the embossing roll is further rotated to pass the deepest part of the pocket and press the next pressing protrusion into the laminate. [Figure 11] FIG. 10 is a cross-sectional view schematically showing the state of a laminate after being pressed using a conventional roll having a pocket portion with a constant depth. [Figure 12] 6 is a cross-sectional view showing an example of the relationship between the length of the arc of the pressing convex portion in the circumferential direction of the roll and the length of the uneven thickness portion of the pocket bottom surface in the circumferential direction of the roll in the embossing roll shown in FIG. 5. [Figure 13]FIG. 13 is a cross-sectional view showing another example of the embossing roll shown in FIG. [Figure 14] FIG. 13 is a cross-sectional view showing still another example of the embossing roll shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] The method for producing a body patch sheet according to the present invention includes a coating step, an embossing step, and a die-cutting step. In the embossing step, an embossing roll is used, which includes a pressing protrusion and a pocket portion having a unique structure defined by the pressing protrusion. In the present invention, "embossing" using the embossing roll refers to the continuous pressing of the viscoelastic layer by the pressing protrusion and smoothing of the viscoelastic layer by the pocket bottom. The viscoelastic layer may include various materials that have adhesiveness, flexibility, and elasticity suitable for application to the body, such as a water-containing gel layer, an oil gel layer, a thermoplastic polymer layer, etc. The viscoelastic material that forms the viscoelastic layer may include various materials that can be applied in the coating step and formed into a sheet-like viscoelastic layer, and may be composed of a single component or a composition composed of multiple components. A preferred embodiment of the method for manufacturing a body patch sheet according to the present invention will be described below with reference to the drawings, using an example in which the viscoelastic layer is a water-containing gel layer and the viscoelastic material body is a water-containing gel body before being formed into the water-containing gel layer.

[0010] FIG. 1 shows a preferred embodiment of the method for manufacturing a body patch sheet of the present invention. The method for manufacturing a body patch sheet of this embodiment includes an application step 10, an embossing step 20, and a die-cutting step 30, which will be described later. As long as a specific embossing roll, which will be described later, is used in the embossing step 20, the other manufacturing steps and manufacturing equipment of the method for manufacturing a body patch sheet of the present invention are not limited to those shown in FIG. 1 and can be appropriately configured. Furthermore, the layer structure of the manufactured body patch sheet is not limited to three layers: a support sheet 100, a separator 200, and a water-containing gel layer 301, but may be four or more layers. For example, the support sheet 100 or the separator 200 may have two or more layers, and additional members may be disposed in the three-layer structure.

[0011] First, the coating step 10 will be described. A long strip-shaped support sheet 100 and a long strip-shaped separator 200 are each unwound and fed out. A hydrogel precursor 300 (including a composition; the same applies hereinafter) is continuously applied onto the support sheet 100 or the separator 200, or between the support sheet 100 and the separator 200 along the longitudinal direction. More specifically, in this embodiment, a hydrous gel precursor 300 kneaded and prepared in a hopper 13 is applied to one surface of the delivered support sheet 100 by a coater 14. Next, a separator 200 is laminated on the surface on which the hydrous gel precursor 300 is exposed. By this coating, the hydrous gel precursor 300 is continuously applied between the support sheet 100 and the separator 200 along the longitudinal direction (line conveying direction, MD direction). As a result, the support 100, separator 200, and hydrous gel precursor 300 are laminated in the longitudinal direction and the width direction (CD direction) perpendicular to the longitudinal direction, and are stretched between a pair of stretching rolls 11 and 12 (hereinafter, the line conveying direction may also be simply referred to as the conveying direction). By this stretching, the hydrogel precursor 300 is formed into a sheet-like hydrogel layer 301, forming a laminate 400 of the support sheet 100, separator 200, and hydrogel layer 301. This laminate 400 is continuously transported downstream and enters the next embossing step 50.

[0012] 1, the hydrous gel precursor 300 is applied to one surface of the support sheet 100, but the present invention is not limited to this. For example, the hydrous gel precursor 300 may be applied to one surface of the separator 200, and the support sheet 100 may be laminated thereon, or the hydrous gel precursor 300 may be applied between the support sheet 100 and the separator 200 when the two sheets are joined together.

[0013] The support sheet 100 described above is a layer that supports the hydrogel layer 301 and serves as a substrate for the hydrogel layer 301 when the body patch sheet 800 is applied to the skin as a finished product. Such a support sheet 100 is made of a flexible, easily deformable material that can conform to the contours of the skin when the body patch sheet 800 is in use. Examples include nonwoven fabric, woven fabric, and deformable thin films with a thickness of 10 μm to 1000 μm, with nonwoven fabric being preferred. The separator 200 is a protective layer for the hydrogel layer 301 before use of the body patch sheet 800 as a finished product, and functions to prevent loss of moisture and other active ingredients in the hydrogel layer 301. The separator 200 is peeled off when the body patch sheet 800 is used as a finished product, and the peeled body patch sheet 800 is used by adhering the exposed surface of the hydrogel layer 301 to the skin. Such separator 200 can be made of various materials without any particular limitations, as long as it protects the hydrogel layer 301 and can be peeled off during use. For example, a hard film can be used, and examples of the film components include polyethylene, polypropylene, polyester, and polystyrene.

[0014] In the above-mentioned coating step 10, the components of the hydrogel precursor 300 are blended and kneaded in a kneader 13 by a conventional method to prepare the hydrogel precursor 300. The blended components can be any components capable of forming the hydrogel precursor 300 for this type of article, without any particular limitations. Examples include a polymer that serves as a gel base, a crosslinking agent, water, and other components. The gel base can also be used alone. This hydrogel precursor 300 undergoes gelation (e.g., cross-linking reaction) over time as it moves from the preparation stage to the final product stage. That is, in the processing stage, it is an intermediate product with a certain degree of fluidity. In the manufacturing method of the present invention, the process from the initial preparation of the gel precursor by the kneader 13 to the application stage is referred to as the "hydrogel precursor 300," and the process from the formation of a sheet by the stretching rolls 11 and 12 onward is referred to as the "hydrogel layer 301."

[0015] The water content of the applied hydrogel precursor 300 is preferably 30% by mass or more, more preferably 30% by mass or more and 90% by mass or less, and even more preferably 30% by mass or more and 85% by mass or less, from the viewpoints of improving the retention of water, medicinal ingredients, and other ingredients, improving the mechanical strength of the hydrogel precursor 300 itself, and improving the flexibility of the resulting hydrogel layer 301.

[0016] When the hydrogel layer 301 is formed by a crosslinking reaction, examples of the polymer component that serves as the gel base material in the hydrogel precursor 300 include polymers having a carboxyl group, a sulfate group, or a phosphate group. Specific examples include carboxyvinyl polymers, anionic cellulose derivatives such as carboxymethyl cellulose and carboxyethyl cellulose, carrageenan, alginic acid and its salts, and anionic starch derivatives. Among these, poly(meth)acrylic acids, anionic cellulose derivatives, and carrageenan are preferred, and carboxymethyl cellulose is more preferred, from the viewpoints of combining a high water retention capacity with sufficient gel strength and flexibility capable of following the irregularities and movements of the skin, as well as the ability to retain a higher amount of water.

[0017] Examples of cross-linking agents contained in the hydrogel precursor 300 include metal ion compounds such as oxides, hydroxides, and salts containing aluminum, magnesium, calcium, potassium, etc.; cationic polymers such as polyamino acids such as polylysine; and polyfunctional epoxy compounds such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, and glycerin triglycidyl ether.

[0018] Various other ingredients can be used depending on the intended use of the body adhesive sheet 800. For example, various drugs such as moisturizers, non-steroidal anti-inflammatory agents, and steroidal anti-inflammatory agents can be used. Examples of moisturizing agents include polyhydric alcohols such as glycerin, propylene glycol, 1,3-butylene glycol, and sorbitol; NMF components such as amino acids and sodium pyrrolidone carboxylate; and water-soluble polymers such as hyaluronic acid, collagen, mucopolysaccharides, and chondroitin sulfate. Non-steroidal anti-inflammatory agents include salicylic acid and its salts, salicylic acid derivatives such as aspirin, acetaminophen, indomethacin, ibuprofen, and ketoprofen. Examples of steroidal anti-inflammatory agents include amcinoid, prednisolone valerate, diflucortolone valerate, betamethasone acetate, hydrocortisone, fluocinonide, clobetasol propionate, and hydrocortisone acetate. In addition to the above, diphenhydramine, lidocaine, vitamin E, glycyrrhetinic acid, or derivatives thereof may also be mentioned, and these may be used alone or in appropriate combination of two or more.

[0019] Next, the embossing step 20 will be described. The embossing step 20 is a step in which the hydrogel layer 301 together with the support sheet 100 and separator 200 is pressed (pushed) together to push out the gel inside before cutting in the die-cutting step 30. The position where the pressing is performed includes the cutting position in the die-cutting step 30 and is an area that circumscribes the edge of the area that will become the finished body-applied sheet. This step makes it possible to prevent cutter contamination in the die-cutting step 30 and to prevent the gel from spilling out from the cross section of the sheet after cutting. In the embossing step 20, the sheet-shaped water-containing gel layer 301 is pressed onto the planar region of the continuously transported laminate 400 from the side of the support sheet 100 or separator 200. More specifically, in this embodiment, the embossing roll 2 and anvil roll 4A are disposed opposite each other and are used as follows. That is, the embossing roll 2 is rotated in the transport direction of the laminate 400 in accordance with the transport speed of the laminate 400 (the rotation speed of the anvil roll 4A). That is, the roll rotation direction X1 (hereinafter simply referred to as the X1 direction) of the embossing roll 2 is aligned with the transport direction of the laminate 400. The embossing roll 2 has, on its circumferential surface, a plurality of patterns 23, each of which includes a pressing protrusion 21 and a pocket portion 22 defined by the pressing protrusion 21, at least in the roll circumferential direction X. As the embossing roll 2 rotates, the plurality of pressing protrusions 21 rotate to continuously perform intermittent pressing on the flat area of ​​the laminate 400. That is, the hydrogel layer 301 in the laminate 400 is intermittently pressed in the transport direction (longitudinal direction). As a result, the water-containing gel layer 301 is pushed out from the pushing position, and the sheet-like water-containing gel layer 301 is divided into a plurality of pieces of a desired size and arranged apart from each other. Details of the embossing roll 2 and the specific embossing action thereof will be described later with reference to FIG. 4 and subsequent figures.

[0020] 1, the embossing roll 2 is pressed against the laminate 400 from the support sheet 100 side, but this is not limiting and the embossing may be performed from the separator 200 side. Furthermore, in the embodiment shown in FIG. 1, the laminate 400 is transported horizontally and embossing is performed at the contact point between the anvil roll 4A and the embossing roll 2, but this is not limiting. For example, the anvil roll 4A may be configured to be capable of drawing negative pressure from its circumferential surface to the inside, and the laminate 400 may be transported along the circumferential surface of the roll by the action of this suction force and pressed onto the circumferential surface of the anvil roll 4A.

[0021] The pressing positions of the pressing protrusions 21 are positions that circumscribe the edge of the area that will become the finished product, body application sheet 800, and can be set appropriately depending on the size of the finished body application sheet 800. These pressing positions may include intermittent positions in the width direction relative to the planar area of ​​the laminate 400, in addition to the aforementioned intermittent positions in the transport direction. At positions intermittently in the conveying direction, it is preferable to form streaky pressing regions transverse to the width direction.At positions intermittently in the width direction, it is preferable to form streaky pressing regions longitudinal to the conveying direction.The transverse pressing regions and the longitudinal pressing regions may each be linear or curved.

[0022] For example, as shown in Fig. 2, an embossing roll 2 may be used in which two dies 23 each including a lattice-shaped pressing protrusion 21 and a rectangular pocket 22 are arranged on the circumferential surface of the roll in the axial direction of the roll and a plurality of dies are arranged in the circumferential direction X of the roll, and lattice pressing is continuously performed in the conveying direction (longitudinal direction). In this case, the hydrogel layer 301 is pressed into the planar region of the laminate 400 in a rectangular pressing region (transverse pressing region M2 + longitudinal pressing region M3) as shown in Fig. 3. This allows the hydrogel layer 301 contained in the laminate 400 to be divided into two sections in the width direction and into a plurality of sections at equal intervals in the conveying direction (longitudinal direction), thereby forming a rectangular region M1 (hereinafter also referred to as the region M1 intended for the body application sheet) that will become the body application sheet 800 as shown in Fig. 3.

[0023] The number of dies 23 in the roll axial direction on the roll circumferential surface of the embossing roll 2 can be set appropriately depending on the size of the body-applied sheet 800 to be produced, and is not limited to two sections, but may be one section, or three or more sections. The number of dies 23 in the roll circumferential direction X is not particularly limited and can be set appropriately depending on the size of the body-applied sheet 800 to be produced. The planar shape of the indentation protrusions 21 (i.e., the body-applied sheet 800 to be produced) is not limited to the rectangular shape described above, and can be various shapes. Furthermore, the indentation protrusions 21 included in each die 23 may or may not be shared between adjacent dies 23 as shown in FIG. 2. If they are not shared, there will be a slight gap between the adjacent indentation protrusions 21 between adjacent dies 23.

[0024] In the die-cutting step 30 following the embossing step 20, the laminate 400 being conveyed is cut at each pressed area (pressed areas M2+M3) using a die-cutting roll 3 having multiple blades 31 on its circumferential surface to cut the body application sheet 800. As shown in FIG. 3, it is preferable to cut at a cut area M4 at the center of the width of each of the pressed areas M2 and M3, as this enhances the effect of preventing leakage of the hydrogel layer 301. Note that this die-cutting step 30 is not limited to a form in which the laminate 400 is placed on an anvil roll 4B as shown in FIG. 1. For example, the embossed laminate 400 may be conveyed horizontally and sandwiched between the die-cutting roll 3 and the anvil roll 4B for cutting. 1, the cut-out body application sheet 800 is preferably conveyed while being sucked by a transfer roll 5 disposed opposite anvil roll 4C, and separated from the remaining part (trim) 409 of the cut-out laminate 400. In this case, the body application sheet 800 is conveyed to a subsequent process by a belt conveyor 61. The trim 409 is collected by a collection roll 62.

[0025] In this embodiment, the embossing roll 2 used in the embossing step 20 has a pocket portion 22 with a unique structure. As shown in FIG. 4, each pocket portion 22 on the roll circumferential surface has the following configuration in a cross-section passing through the pocket portion 22 perpendicular to the roll axis of the embossing roll 2. That is, each pocket portion 22 has different pocket depths in the normal direction with respect to the roll circumferential direction X, with the normal line ST at the center between the center positions 21C, 21C of the pushing convex portions 21, 21 before and after in the roll circumferential direction X as a reference (hereinafter, this reference normal line is also referred to as the reference line ST). More specifically, as shown in FIG. 5, the deepest part 22D of the pocket portion 22 is on the upstream side 211 in the roll rotation direction X1 from the reference normal line ST, and the pocket depth is shallower on the downstream side 212 in the roll rotation direction X1 from the reference normal line ST than on the upstream side 211 (E1 < E2). On the downstream side 212, the pocket bottom surface 22M is configured such that the difference from the roll outer circumference R1 in the normal direction gradually decreases or remains constant in the downstream direction, or is a combination of the gradual decrease and the constant. Stated differently, the pocket depth on the downstream side 212 gradually decreases or remains constant in the downstream direction, or is a combination of the gradual decrease and the constant. Note that the upstream side 211 in the roll rotation direction X1 is the left side in FIG. 4, and the downstream side 212 is the right side.

[0026] The center position 21C of the above-mentioned pushing convex portion 21 means the middle position of the length of the pushing convex portion 21 in the roll circumferential direction X. As described above, when the pushing convex portions 21 are not shared between adjacent molds 23, 23 and there is a slight gap between adjacent pushing convex portions 21, 21, the center position 21C of the pushing convex portion 21 is the middle position of the length in the roll circumferential direction X including the adjacent pushing convex portions 21, 21 and the gap. In this case, the center position 21C of the pushing convex portion 21 is usually arranged at the position of the gap.

[0027] The normal line mentioned above refers to a straight line perpendicular to a tangent to the roll outer periphery R1 at a certain point on the roll peripheral surface in a cross section passing through the pocket portion 22 perpendicular to the roll axis of the embossing roll 2. The normal direction refers to the direction in which the perpendicular line extends. The roll outer periphery R1 refers to the circumference R1, which is a concentric circle of the embossing roll 2 and connects the tops of the pressing protrusions 21. The center between the center positions 21C, 21C where the reference line ST is located refers to the position on the circumference R1 that bisects the arc between the normal lines 21T, 21T passing through the center positions 21C, 21C.

[0028] The upstream side 211 of the embossing roll 2 means the side in front of the reference line ST in the roll rotation direction X1 for each pocket portion 22. The downstream side 212 of the embossing roll 2 means the side facing the reference line ST in the roll rotation direction X1 for each pocket portion 22. Note that the upstream side and downstream side of the embossing roll 2 correspond to the upstream side and downstream side of the laminate 400 on the assumption that the embossing roll 2 rotates in the transport direction of the laminate 400.

[0029] 5 shows that the difference (pocket depth E1) between the pocket bottom surface 22M and the roll outer periphery R1 in the normal direction gradually decreases downstream on the downstream side 212 of the reference line ST in the roll rotation direction X1, but is not limited to this. As long as the effect described below can be achieved, the difference (pocket depth E1) between the pocket bottom surface 22M on the downstream side 212 and the roll outer periphery R1 in the normal direction may be constant under the relationship "pocket depth E1 on the downstream side 212 < pocket depth E2 on the upstream side 211." That is, the pocket bottom surface 22M on the downstream side 212 of the reference line ST may describe an arc that forms a circle with the embossing roll 2. Alternatively, under the relationship "pocket depth E1 on the downstream side 212 < pocket depth E2 on the upstream side 211," the difference (pocket depth E1) between the pocket bottom surface 22M on the downstream side 212 and the roll outer periphery R1 in the normal direction may be configured to gradually decrease and be a constant combination.

[0030] In the embossing step 20, the embossing roll 2 is rotated in the transport direction of the laminate 400 (the roll rotation direction X1 is aligned with the transport direction of the laminate 400) to continuously emboss the water-containing gel layer 301. As described above, the "embossing" by the embossing roll 2 means successively performing the pressing process by the pressing convex portions 21 and the smoothing process by the pocket bottom surfaces 22M of the extruded water-containing gel layer 301, which will be described later.

[0031] As the embossing roll 2 rotates, the hydrogel layer 301 of the laminate 400 is continuously pressed intermittently, and the hydrogel layer 301 is extruded from the pressing regions M2+M3 to the surrounding area by the pressing protrusions 21. As shown in FIG. 6, in the pressing region M3, the hydrogel layer 301 is extruded almost evenly to the left and right (up and down on the paper) (arrow S2), but in the pressing region M2, most of the hydrogel layer 301 escapes to the region M1 intended for the body application sheet, which is upstream in the transport direction of the laminate 400 (arrow S1). This is for the following reason: As shown in FIGS. 7(A) to 7(D), as the embossing roll 2 rotates in the X1 direction, along the transport direction of the laminate 400, one pressing protrusion 21 penetrates the laminate 400 from a corner, gradually increasing the amount of penetration. The water-containing gel layer 301 extruded by the intrusion has no escape route because the tip of the indentation protrusion 21, which rotates in the X1 direction along the conveyance direction, is located downstream of the pressing region M2. Furthermore, the progression of the laminate 400 downstream (arrows F1, F2, F3, F4) assists the movement of the water-containing gel layer 301 upstream. Therefore, the upstream side of the pressing region M2 becomes an escape route for the water-containing gel layer 301, and most of the extruded water-containing gel layer 301 is pushed out to the upstream side of the indentation protrusion 21 and rises up. As a result, at the stage when the pressing protrusion 21 is pressed into the laminate 400, as shown in Figure 7 (D), the thickness deviation portion 302 of the hydrogel layer 301 at the upstream edge of the pressing area M2 (the downstream edge of the intended area M1 of the sheet to be applied to the body) becomes thicker than the thickness deviation portion 303 of the hydrogel layer 301 at the downstream edge of the pressing area M2 (the upstream edge of the intended area M1 of the sheet to be applied to the body).

[0032] In the manufacturing method of the body adhesive sheet of this embodiment, the embossing roll 2 has the pocket portion 22 with the above-mentioned unique structure, which makes it possible to level the thickness of the uneven thickness portion 302 and reduce the difference in thickness (thickness difference) between the uneven thickness portion 302 and the uneven thickness portion 303 before and after the pressing convex portion 21. This leveling process is performed continuously as the embossing roll 2 rotates, following the above-mentioned pressing process. This will be described with reference to FIGS. As shown in FIG. 8(A), while the laminate 400 is conveyed along the conveyance direction (arrow F5), the pressing protrusions 21 of the embossing roll 2, rotating in the X1 direction, press the laminate 400 to extrude the hydrogel layer 301 in the pressing region M2 of the laminate 400. The pocket depths of the pockets 22, which vary across the reference line ST as described above, have a unique effect on the extruded hydrogel layer 301. First, the pocket depth E21 of the deepest pocket portion 22D on the side where the pressing protrusions 21 first enter the laminate 400 is deeper than the pocket depth E11 of the shallowest pocket portion 22S on the side that subsequently contacts the laminate 400. This allows the rotating pressing protrusions 21 to press the laminate 400 to a depth equal to the pocket depth E21 relative to its thickness, firmly extruding the hydrogel layer 301 inside. As described above, most of the extruded hydrogel layer 301 escapes upstream (arrow S1 in FIG. 8(A)). In contrast, the pocket depth E1 of the pocket portion 22 at the escape destination is shallow (pocket depth E11 at its shallowest point), and therefore the pressing force (arrow P1 in FIG. 8(A)) on the hydrogel layer 301 at the pocket bottom surface 22M acts correspondingly strongly. As shown in FIG. 9, this action of the pocket bottom surface 22M continues continuously to the position of the reference line ST or its vicinity as the embossing roll 2 rotates in the X1 direction. As a result, while the laminate 400 is conveyed along the conveyance direction (arrow F6), the extruded hydrogel layer 301 is leveled toward the rear side (upstream side), and the thickness of the uneven thickness portion 302 of the hydrogel layer 301 at the downstream edge of the intended region M1 of the body application sheet can be reduced and flattened. Furthermore, as the embossing roll 2 rotates in the X1 direction, the laminate 400 is further conveyed along the conveyance direction until it passes the reference line ST and the next pressing protrusion 21 is reached (arrow F7), as shown in FIG. 10. In pocket portion 22 including pocket deepest portion 22D on the upstream side beyond reference line ST, the extruded uneven thickness portion of hydrous gel layer 301 of laminate 400 is smoothly distributed along the pocket shape. In this way, it is possible to reduce the difference in thickness (thickness difference) between uneven thickness portion 302 and uneven thickness portion 303 of hydrous gel layer 301 shown in Figure 7(D). As described above, the embossing roll 2 can continuously perform good embossing processing by its pushing and leveling actions. That is, pocket depth E21 firmly pushes hydrogel layer 301 upstream, effectively preventing contamination of the blade during the subsequent die-cutting process, while pocket depths E11 to E1 can suppress the resulting thickness deviation. Furthermore, by using embossing roll 2, there is no need to temporarily stop the line for embossing, and continuous embossing using embossing roll 2 can efficiently produce the body adhesive sheet 800 as a product, improving productivity.

[0033] On the other hand, conventional rolls with constant pocket depths cannot achieve the above-mentioned effect. For example, if the pocket depth E21 is constant from the perspective of sufficient extrusion of the hydrogel layer 301, the aforementioned pressing force P1 effect is not obtained, and thickness variations are not suppressed. For example, as shown in Figure 11, in the region M1 intended for the body application sheet, the thickness variations 302 downstream in the conveying direction are thicker than the thickness variations 303 upstream, resulting in a large thickness variation. Furthermore, if the pocket depth E11 is constant and shallow, it is difficult to sufficiently extrude the hydrogel layer 301 in the pressing region M2, which may result in contamination of the blade during the subsequent die-cutting process. Furthermore, if the pocket depth E11 is constant and shallow, the pressing force P1 is applied excessively to the entire region M1 intended for the body application sheet of the laminate 400, which may result in tearing of the support sheet 100 and separator 200 or leakage of the hydrogel layer 301. In some cases, the extruded hydrogel layer may not be able to fit into the pocket and may protrude into another area. In contrast, in the method for producing a body patch sheet of this embodiment, by using the above-mentioned embossing roll 2, sufficient extrusion of the water-containing gel layer 301 and suppression of thickness variations of the water-containing gel layer 301 before and after the pressing convex portions 21 in the roll rotation direction X1 are simultaneously achieved. That is, thickness variations before and after the pressing convex portions 21 that occur due to continuous pressing using the embossing roll 2 can be suitably leveled and suppressed. Furthermore, continuous embossing using the embossing roll 2 can increase the productivity of the body patch sheet 800.

[0034] In such an embossing roll 2, the reference line ST is positioned at the center between the center positions 21C, 21C, which is the center position in the MD direction of the sheet product to be applied to the body from the viewpoint of effectively exerting the above-mentioned effect, and serves as a standard for controlling the balance of the sheet thickness.

[0035] In the manufacturing method of the body adhesive sheet of this embodiment, from the viewpoint of making the above-mentioned action of the pocket portion 22 more effective, it is preferable that the embossing roll 2 has a pocket bottom surface 22M on the upstream side 211 of the reference line ST, the difference (pocket depth E2) between the pocket bottom surface 22M and the roll outer circumference R1 in the normal direction gradually increasing toward the upstream direction. This allows the hydrogel layer 301 to be formed smoothly relative to the extruded hydrogel layer 301, and enables the hydrogel layer 301 to be distributed in the same manner even when the thickness varies during processing.

[0036] 12, in the method for manufacturing a body application sheet of this embodiment, it is preferable that the length Z2 of the uneven thickness portion 24 in the roll circumferential direction X of the pocket bottom surface 22M of the pocket portion 22 is greater than the arc length Z1 in the roll circumferential direction X of one pressing protrusion 21 in each mold 23. This makes it possible to reduce the size of the embossed portion (pressed region M2) relative to the body application sheet and suppress the overall amount of uneven thickness.

[0037] The uneven thickness portion 24 here refers to the pocket bottom surface 22M in the range where the pocket depth is not constant. In other words, it refers to the portion where the pocket bottom surface 22M does not form a concentric arc of the embossing roll 2. 12, with regard to the pocket depth, which is the difference between the pocket bottom surface 22M and the roll outer circumference R1 in the normal direction, on the upstream side 211 of the reference line ST, the pocket depth E2 gradually increases toward the upstream direction, while on the downstream side 212 of the reference line ST, the pocket depth E1 gradually decreases toward the downstream direction. In this embodiment, the entire pocket bottom surface 22M constituting one mold 23 is the uneven thickness portion 24. The space of the pocket portion 22 corresponding to the uneven thickness portion 24 of the pocket bottom surface 22M is referred to as the uneven depth space 22V. In Figure 13, the pocket depth, which is the difference between the pocket bottom surface 22M and the roll outer circumference R1 in the normal direction, gradually increases in pocket depth E2 upstream of the reference line ST on the upstream side 211 of the reference line ST, while the pocket depth E1 is constant downstream of the reference line ST on the downstream side 212 of the reference line ST. In this embodiment, of the pocket bottom surface 22M constituting one mold 23, the upstream side 211 of the reference line ST forms a non-uniform thickness portion 24. In this case, the pocket depth E1 downstream of the reference line ST is equal to the pocket depth E11 of the shallowest pocket portion 22S described above. The pocket bottom surface 22M where the pocket depth E1 is constant is referred to as a uniform thickness portion 25, and the space of the pocket portion 22 corresponding to the uniform thickness portion 25 is referred to as a uniform depth space 22F. 14, with regard to the pocket depth, which is the difference between the pocket bottom surface 22M and the roll outer periphery R1 in the normal direction, on the upstream side 211 of the reference line ST, the pocket depth E2 gradually increases toward the upstream direction, and on the downstream side 212 of the reference line ST, the pocket depth E1 gradually decreases until halfway in the downstream direction, and further downstream, the pocket depth E1 is constant (E1 = E11). In this embodiment, of the pocket bottom surface 22M constituting one mold 23, parts of the upstream side 211 and the downstream side 212 of the reference line ST form uneven thickness portions 24. The length Z2 of the uneven thickness portion 24 of the pocket bottom surface 22M in the roll circumferential direction X and the arc length Z1 of the indentation protrusion 21 in the roll circumferential direction X can be measured by measuring the outer surface of the roll rotated at a constant speed with a laser displacement meter, or by using a measuring device such as a tape measure or vernier calipers.

[0038] In order to make the above-mentioned effect of "arc length Z1 < length Z2 of uneven thickness portion 24" more effective, in each die 23, the length Z2 of uneven thickness portion 24 in the roll circumferential direction X of pocket bottom surface 22M is preferably greater than twice the arc length Z1 of one pressing protrusion 21 in the roll circumferential direction X, more preferably three times or more, and even more preferably four times or more. Furthermore, the length Z2 of the uneven thickness portion 24 is preferably 50 times or less, more preferably 40 times or less, and even more preferably 30 times or less, the arc length Z1 in order to prevent the gel from being extruded from the embossed portion and the gel from spilling out from the cut end of the sheet for application to the body.

[0039] In the manufacturing method of the body application sheet of this embodiment, with respect to the pocket portion 22 of each mold 23 of the embossing roll 2, the pocket depth E1 on the downstream side 212 and the pocket depth E2 on the upstream side 211, which are the differences between the pocket bottom surface 22M and the roll outer circumference R1 in the normal direction, as well as the degree of gradual reduction of the pocket depth E1 and the degree of gradual expansion of the pocket depth E2, can be appropriately set according to the thickness H1 of the laminate 400 and the length of the pocket portion 22 in the roll circumferential direction X, from the viewpoint of effectively exerting the above-mentioned effect. In particular, in order to make the above-mentioned effects more effective, it is preferable that the relationship between the pocket depth E21 of the deepest pocket portion 22D, the pocket depth E11 of the shallowest pocket portion 22S, and the thickness H1 of the laminate 400 (see Figures 8(A) and (B)) be as follows. That is, it is preferable that the pocket depth E21 of the deepest pocket part 22D is 100% to 150% of the thickness H1 of the laminate 400, and the pocket depth E11 of the shallowest pocket part 22S is 50% to 90% of the thickness H1 of the laminate 400.

[0040] Furthermore, in the method for producing a body patch sheet of this embodiment, the viscosity of the water-containing precursor 300 during production of the body patch sheet is preferably 70,000 cp or more, more preferably 80,000 cp or more, and even more preferably 100,000 cp or more. Generally, the higher the viscosity of the water-containing gel precursor 300, the thicker the thickness-uneven portion 302 described above tends to be, and therefore the effect of suppressing thickness unevenness in the embossing roll 2 becomes more pronounced. Furthermore, using a water-containing gel precursor 300 with a high viscosity as described above has the advantage that the film thickness during and after application is stable during production and processing fluctuations are suppressed, and the produced body patch sheet 800 exhibits high performance in terms of quality stability and shape retention. In order to facilitate deformation of the hydrogel into a desired shape by processing, the viscosity of the hydrogel precursor 300 during production of the body patch sheet is preferably 200,000 cp or less, more preferably 180,000 cp or less, and even more preferably 160,000 cp or less.

[0041] (Method for measuring viscosity of hydrogel precursor) At a temperature of 20°C and humidity of 50%, the hydrogel precursor can be measured within 15 minutes after production using a helical viscometer (manufactured by TOKI SANGYO.CO.LTD) with spindle No. TE at a rotation speed of 5 r / min for 1 minute.

[0042] When the body adhesive sheet is in use, the usage time is limited due to the loss of moisture from the body adhesive sheet due to moisture evaporation. From the viewpoint of extending the applicable time of the body adhesive sheet, the basis weight of the water-containing gel layer 301 formed into a sheet is set to 800 g / m 2 More than 900g / m 2 More preferably, 1,000g / m 2 The above is more preferable. The basis weight of the sheet-shaped hydrogel layer 301 is set to 1,500 g / m2 from the viewpoint of preventing the sheet from peeling off easily during use due to its rigidity. 2 Preferably less than 1,400 g / m 2 Less than 1,300 g / m is more preferable. 2 The following is even more preferable. The basis weight of the hydrogel layer 301 formed into a sheet as referred to here means the weight before entering the embossing step 20. In the method for manufacturing a body patch sheet of this embodiment, as described above, it is possible to manufacture a body patch sheet with uniform thickness and basis weight by suppressing thickness deviation, and therefore it is possible to make the performance according to the above basis weight be uniformly exhibited within the manufactured body patch sheet. [Example]

[0043] The present invention will be explained in more detail below with reference to examples, but the present invention should not be construed as being limited thereto.

[0044] Example 1 The method for manufacturing the body patch sheet shown in Fig. 1 was carried out using the embossing roll 2 shown in Figs. 4, 5 and 12. The components of the hydrogel precursor 300 used in the application step 10 were water, polyvinyl alcohol, carboxymethyl cellulose, a crosslinking agent and a moisturizing agent. The viscosity of the hydrogel precursor 300 was 700,000 cp. The basis weight of the hydrogel layer 301 formed into a sheet was 1,250 g / m 2 The thickness H1 of the laminate 400 was set to 2 mm. Furthermore, in each die 23 on the roll peripheral surface of the embossing roll 2, the pocket depth E2, which is the difference between the roll outer periphery R1 in the normal direction of the pocket bottom surface 22M on the upstream side 211 of the reference line ST, was gradually increased toward the upstream direction, and the pocket depth E21 of the deepest pocket portion 22D was set to 2 mm. In addition, the pocket depth E1, which is the difference between the roll outer periphery R1 in the normal direction of the pocket bottom surface 22M on the downstream side 212 of the reference line ST, was gradually decreased toward the downstream direction, and the pocket depth E11 of the shallowest pocket portion 22S was set to 1.2 mm. That is, in each die 23, the entire pocket bottom surface 22M was defined as the unevenly thick portion 24, and the space of the entire pocket portion 22 was defined as the unevenly deep space 22V. The length of the pocket portion 22 in the roll circumferential direction X was set to 85 mm.

[0045] (Comparative Example) The method for manufacturing a body adhesive sheet was carried out in the same manner as in the example, except that for the mold 23 of the embossing roll 2, the pocket depth E21 of the deepest pocket part 22D was set to 2 mm, and the pocket depth was constant throughout the pocket part 22.

[0046] In the body patch sheet obtained as a result of the manufacturing method of the Comparative Example, the difference in thickness between the uneven thickness portion 302 and the uneven thickness portion 303 was 0.22 mm, whereas in the body patch sheet obtained as a result of the manufacturing method of the Example, the difference in thickness was 0.04 mm, and the difference in thickness was able to be suppressed. In other words, it was found that by using the manufacturing method of the body patch sheet of the present invention, it is possible to suppress the difference in thickness of the hydrogel layer before and after the pressing convex portion in the roll rotation direction, which occurs when continuous pressing is performed using an embossing roll. [Explanation of symbols]

[0047] 10 Coating process 20 Embossing process 30 Die-cutting process 100 Support sheet 200 Separator 300 Viscoelastic material (hydrogel precursor) 301 Viscoelastic layer (hydrogel layer) 400 laminate 800 Body adhesive sheet 2 Embossing roll 21 Press-in convex part 22 Pocket 23-inch 21C Center position of the pressing convex part (middle position of the length in the roll circumferential direction) 21T Normal at the center of the center position ST baseline 22D Deepest part of the pocket E1, E2 pocket depth X Roll circumferential direction X1 Roll rotation direction

Claims

1. a coating step of feeding out a long strip-shaped support sheet and a long strip-shaped separator, and continuously coating a viscoelastic material on the support sheet or the separator, or between the support sheet and the separator, along the longitudinal direction to form a sheet-shaped viscoelastic layer, thereby forming a laminate of the support sheet, the viscoelastic layer, and the separator; an embossing step of pressing the sheet-shaped viscoelastic layer into the planar region of the laminate from the side of the support sheet or the separator, thereby dividing the viscoelastic layer into a plurality of pieces of desired size and arranging the pieces apart from each other; a die-cutting step of cutting the laminate at each pressed area to die-cut out a body adhesive sheet, In the embossing step, the viscoelastic layer is embossed by rotating an embossing roll having a plurality of dies, each including a press-in protrusion on the roll peripheral surface at least in the roll peripheral direction, the dies including the press-in protrusion and the pocket portion defined by the press-in protrusion, the pocket depth in the normal direction to the roll peripheral direction differs with respect to each of the pocket portions, based on a normal line at the center between center positions of the front and rear press-in protrusions in the roll peripheral direction, the deepest part of the pocket portion is located upstream of the reference normal line in the roll rotation direction, and the pocket depth is shallower on the downstream side of the reference normal line in the roll rotation direction than on the upstream side, and when the roll peripheral surface at the pocket portion is taken as the pocket bottom surface, the difference between the pocket bottom surface and the outer periphery of the roll in the normal direction gradually decreases or is constant, or a combination of the gradual decrease and the constant difference, toward the downstream side. A method for manufacturing a sheet for application to the body.

2. 2. The method for manufacturing a body patch sheet according to claim 1, wherein in the embossing roll, the difference between the bottom surface of the pocket upstream of the reference normal line and the outer periphery of the roll in the normal line direction gradually increases toward the upstream direction.

3. 3. The method for manufacturing a body patch sheet according to claim 1 or 2, wherein in each of the molds, the length of the uneven thickness portion of the pocket bottom surface in the circumferential direction of the roll is greater than the arc length of one of the pressing convex portions in the circumferential direction of the roll.

4. 4. The method for manufacturing a body patch sheet according to claim 3, wherein in each of the molds, the length of the uneven thickness portion of the pocket bottom surface in the circumferential direction of the roll is greater than twice the arc length of one of the pressing convex portions in the circumferential direction of the roll.

5. 3. The method for producing a body patch sheet according to claim 1, wherein the viscosity of the viscoelastic material during production of the body patch sheet is 70,000 cp or more.

6. The viscoelastic layer formed into a sheet has a basis weight of 800 g / m ２ The method for producing the body adhesive sheet according to claim 1 or 2, which is as described above.

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