Apparatus and method for producing absorbent sanitary article
By using smooth cylindrical compression rollers and adjustable pitch compression roller technology, traditional synthetic adhesives are solved inadequate bonding strength and penetration in biodegradable sanitary products, achieving efficient bonding and softness of biodegradable sanitary products, ensuring the biodegradability and comfort of the product.
Patent Information
- Application Number
- JP2024120832
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-07-27
- Filing Date
- 2024-07-26
- Publication Date
- 2025-02-06
AI Technical Summary
In the prior art, when using traditional synthetic adhesives to manufacture biodegradable sanitary products, there are problems of insufficient bonding strength and increased product hardness. Especially when using water-based biodegradable materials, the adhesive is insufficient penetration and drying time is too long, resulting in unsuitable product suitability and poor user experience during the manufacturing process.
The multi-layer sanitary material is compressed using a device that includes a compression roller with a smooth cylindrical outer surface and an adjustable pitch compression roller, combined with the use of water-based biodegradable adhesives, ensuring effective bonding between the materials by precisely controlling the compression force and adhesive distribution while reducing adhesive penetration into the absorbent core.
It realizes efficient bonding of biodegradable sanitary products, avoids adhesive penetration into the absorbent core, maintains product flexibility and comfort, and ensures product biodegradability.
Smart Images
Figure 2025019041000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to an apparatus and method for producing absorbent sanitary products. [Background technology]
[0002] Examples of absorbent sanitary products include feminine sanitary napkins, baby diapers, incontinent diapers and pads, etc. Non-limiting examples of feminine sanitary napkins are described below.
[0003] Structurally, feminine sanitary napkins include several elements that are layered over one another.
[0004] The feminine sanitary napkin is worn by placing it against the inside of an undergarment worn by the user with its first adhesive portion, folding the two opposing flaps over the outside of the undergarment, and securing the flaps to the undergarment with their respective second adhesive portions.
[0005] Typically, feminine sanitary napkins comprise a top sheet and a back sheet which are joined together and have an absorbent core disposed between the top sheet and the back sheet.
[0006] The topsheet is made from a fluid-permeable material and is configured to be placed facing and in contact with the body of the wearer when the sanitary napkin is placed in an undergarment.
[0007] The absorbent core has the function of absorbing body fluids through the topsheet and retaining them without leakage for even several hours. The absorbent core contains an absorbent material, typically in granular or powder form, called SAP (acronym for "Super Absorbent Powder"), capable of absorbing up to 300 times its own weight and up to 60 times its own volume in liquid.
[0008] The backsheet is configured to be attached to the undergarment by the first adhesive portion and is fluid impermeable to avoid leakage of liquids absorbed by the absorbent core.
[0009] To produce an absorbent article, a multi-layer web is formed by successively overlapping a back sheet web in the form of a continuous web and a top sheet web in the form of a continuous web with a plurality of absorbent cores disposed therebetween. The top sheet and the back sheet are joined together, and the multi-layer web is then cut around each absorbent core to produce a plurality of semi-finished absorbent articles, with the cut top sheet web defining the top sheet of the absorbent article and the cut back sheet web defining the back sheet of the absorbent article, with an absorbent core disposed therebetween, for each semi-finished absorbent article.
[0010] Conventionally, the top sheet web and the back sheet web of a multi-layer web are joined by heat sealing, which is accomplished by compressing the top sheet web and the back sheet web together at the edges of the absorbent core with a knurled or dotted roller, optionally with the addition of a conventional synthetic adhesive. At room temperature, conventional synthetic adhesives are solid and are briefly heated to a liquid state for application.
[0011] Applicants have found that conventional adhesives, due to their relatively high viscosity and short setting times, do not adequately penetrate and spread within the multi-layer web when applied.
[0012] In markets that are more sensitive to environmental issues, regulators and consumers favor biodegradable products.
[0013] Therefore, recently, biodegradable feminine sanitary napkins that can be disposed of in the toilet and dissolve in water within a period of days, weeks or months have been considered. In these products, the top sheet web, the back sheet web and the absorbent core are made of biodegradable materials, for example of the cellulose type.
[0014] Applicants have discovered that webs made from biodegradable materials are not heat sealable and that traditional synthetic adhesives are not biodegradable.
[0015] The applicant has realised that it is possible to use a biodegradable type adhesive instead of the conventional synthetic adhesives to bond the top and back sheet webs and the absorbent core together whilst maintaining the biodegradable properties of the product.
[0016] The applicant has found that current biodegradable adhesives are typically water-based, liquid at room temperature, and, unlike conventional adhesives, have particularly low viscosity. Biodegradable adhesives also generally take a long time to completely dry, sometimes up to several days, and therefore remain liquid for a much longer period of time after application than conventional adhesives. Thus, biodegradable adhesives generally have weaker adhesive strength than conventional adhesives during processing steps after application and at least until they cure.
[0017] The applicant has found that in order to adequately bond a top sheet web and a back sheet web of a biodegradable material with a biodegradable adhesive, a greater amount of adhesive must be used and the top sheet web and back sheet web must be compressed together after application of the adhesive.
[0018] On the other hand, the Applicant has discovered that when the multi-layer web is compressed in a conventional manner after application of a biodegradable adhesive, the adhesive tends to penetrate into the top sheet web and the back sheet web and impregnate the absorbent core, resulting in a hard product and discomfort to the user. Summary of the Invention [Means for solving the problem]
[0019] Thus, a first aspect of the present invention relates to an apparatus for producing absorbent sanitary products.
[0020] Preferably, a smooth support surface is provided.
[0021] Preferably, a forming unit is provided that is configured to form a multi-layer web for an absorbent sanitary article, the multi-layer web including a top sheet web, a back sheet web, and a plurality of absorbent cores disposed between the top sheet web and the back sheet web.
[0022] Preferably, the forming unit is configured to supply said multi-layer web to said support surface.
[0023] Preferably, at least one adhesive dispenser is provided configured to dispense a liquid adhesive onto said backsheet web and / or said topsheet web.
[0024] Preferably, at least one compression roller is provided adjacent said support surface and configured to press said multi-layer web against said support surface.
[0025] Preferably, the at least one compression roller has a smooth cylindrical outer surface.
[0026] A compression roller having a smooth cylindrical outer surface presses the multi-layer web against a smooth support surface. Applicant has discovered that by eliminating small irregularities on the outer surface of the compression roller, adhesive penetration into the top and back sheet webs of the multi-layer web and into the absorbent core is reduced, and uniform compression is achieved which avoids areas of undesirable adhesive thickening.
[0027] A second aspect of the invention relates to a method for producing an absorbent sanitary product.
[0028] Preferably, a multi-layer web of an absorbent sanitary article is formed, comprising a top sheet web, a back sheet web, and a plurality of absorbent cores disposed between the top sheet web and the back sheet web.
[0029] Preferably, the multi-layer web is provided on a smooth supporting surface.
[0030] Preferably, a liquid adhesive is dispensed onto said back sheet web and / or said top sheet web.
[0031] Preferably, the multi-layer web is compressed between at least one compression roller and the support surface.
[0032] Preferably, the at least one compression roller has a smooth cylindrical outer surface.
[0033] Preferably, the method according to the second aspect of the invention may be carried out by using an apparatus according to the first aspect of the invention.
[0034] In the remainder of the specification and in the appended claims, "smooth surface" (particularly smooth support surface, smooth cylindrical outer surface and smooth raised surface) means a uniform surface free of depressions, protrusions, bumps, holes, minute irregularities and other obvious irregularities, with a surface roughness of less than 100 μm, preferably less than 10 μm.
[0035] In the following description and in the appended claims, terms such as "upstream," "downstream," and similar terms refer to the path of movement of the multi-layer web, and of the individual elements that make up the multi-layer web, through the apparatus, unless otherwise specified.
[0036] The present invention may, in any of the above aspects, have at least one of the preferred features described below, and such features may therefore be present individually or in combination with each other, unless otherwise specified, in both the apparatus of the first aspect of the invention and the method of the second aspect of the invention.
[0037] Preferably, said smooth cylindrical outer surface defines the entire side of said at least one compression roller.
[0038] Preferably, a first adhesive dispenser is provided configured to dispense a liquid adhesive onto said top sheet web.
[0039] Preferably, a second adhesive dispenser is provided configured to dispense liquid adhesive onto the backsheet web.
[0040] In this way, a better bond between the top sheet web and the back sheet web is obtained.
[0041] Preferably, the backsheet web and / or the topsheet web are impregnated with a liquid adhesive prior to forming the multi-layer web.
[0042] Preferably, said at least one compression roller is mounted a respective adjustable distance from said support surface.
[0043] The applicant has determined that the shorter the distance between the compression roller and the support surface, the greater the compression the multi-layer web is subjected to and the better the bond obtained between the layers of the multi-layer web. The applicant has found that over-compressing the multi-layer web can promote leakage of adhesive into the absorbent core. By allowing the distance between the compression roller and the support surface to be adjusted, the level of compression can be adjusted to balance the need to prevent leakage with the need to improve bond.
[0044] Preferably, there is a scraper adjacent the outer cylindrical surface of at least one of the compression rollers.
[0045] Preferably, the scraper is configured to scrape the outer cylindrical surface of the at least one compression roller and remove contaminants from said outer cylindrical surface.
[0046] Applicant has determined that by employing back and top sheet webs that are at least partially composed of biodegradable fibers, such as cellulose, and by impregnating such webs with a water-based biodegradable adhesive, these webs tend to release adhesive-laden fibers that can contaminate the smooth surface of the compression roller and cause unevenness in the smooth surface.
[0047] Applicants have found that by providing a scraper on a smooth cylindrical exterior surface, contaminants can be continuously removed while the device is in operation.
[0048] Preferably, a first compression roller is provided.
[0049] Preferably, said first compression roller is mounted a first distance from said support surface.
[0050] Preferably, the first distance is adjustable.
[0051] Preferably, said first distance is comprised in the range 1.2 mm to 2.5 mm, preferably 1.5 mm to 2 mm, more preferably 1.6 mm to 1.9 mm, for example equal to about 1.7 mm.
[0052] Preferably, a second compression roller is provided.
[0053] Preferably, the second compression roller is configured to press the multi-layer web against the support surface.
[0054] Preferably, the second compression roller has a smooth cylindrical outer surface.
[0055] Preferably, the smooth outer cylindrical surface corresponds to the entire cylindrical side surface of the second compression roller.
[0056] Preferably, the second compression roller is disposed downstream of the first compression roller.
[0057] The applicant has discovered that by providing two successive compression rollers, it is possible to gradually compress the multi-layer web and improve the adhesion between the layers of the multi-layer web, thereby reducing penetration of adhesive into the absorbent core.
[0058] Preferably, the second compression roller is mounted a second distance from the support surface.
[0059] Preferably, the second distance is less than the first distance.
[0060] Preferably, said second distance is comprised in the range 1 mm to 2 mm, preferably 1.2 mm to 1.7 mm, more preferably 1.3 mm to 1.6 mm, for example equal to about 1.5 mm.
[0061] Applicant has found that by providing a compression level of the second roller that is slightly higher than the compression level of the first roller, leakage of adhesive into the absorbent core is reduced and adhesion between the layers of the multi-layer web is improved.
[0062] Preferably, the second distance is adjustable.
[0063] Preferably, there is a scraper adjacent the outer cylindrical surface of the second compression roller.
[0064] Preferably, said scraper of the second compression roller is configured to scrape the outer cylindrical surface of the second compression roller to remove contaminants therefrom.
[0065] Preferably, a support drum is provided.
[0066] The support drum supports and delivers the multi-layer web coming from the forming unit.
[0067] Preferably, said support surface is defined on an outer cylindrical surface of said support drum.
[0068] Preferably, the at least one compression roller is substantially adjacent to the support drum.
[0069] Preferably, the axis of rotation of the compression roller and the axis of rotation of the support drum are parallel.
[0070] Preferably, the axis of rotation of the compression roller and the axis of rotation of the support drum lie in a radial plane for both the compression roller and the support drum.
[0071] Preferably, said support surface has a width equal to or greater than the width of the multi-layer web, the width of the support surface being measured in a direction parallel to the axis of rotation of the support drum, the width of the multi-layer web being measured in a direction perpendicular to the main longitudinal development direction of the multi-layer web and parallel to the axis of rotation of the support drum.
[0072] Preferably, the multi-layer web is fed onto a support surface.
[0073] Preferably, the multi-layer web is fed between a support surface and at least one compression roller.
[0074] Preferably, the multi-layer web is fed between the support surface and a second compression roller.
[0075] Preferably, a contact surface is provided downstream of said support surface and configured to receive said multi-layer web.
[0076] Preferably, the contact surface is smooth.
[0077] Preferably, said contact surface is defined on a contact roller.
[0078] Preferably, the apparatus is configured to deliver the multi-layer web coming from the support surface to the contact surface.
[0079] Preferably, a sealing roller is provided adjacent the contact surface.
[0080] Preferably, the sealing roller faces the counter roller.
[0081] Preferably, the sealing rollers are configured to seal the top sheet web and the back sheet web around each absorbent core of a multi-layer web of an absorbent sanitary article.
[0082] Preferably, the sealing roller has a cylindrical bottom surface defined at a first radial distance from an axis of rotation of the sealing roller.
[0083] Preferably, the sealing roller has a raised surface defined at a second radial distance from the axis of rotation that is greater than the first radial distance.
[0084] Preferably, the raised surface is smooth.
[0085] Preferably, said sealing roller is pressed against said contact surface.
[0086] Preferably, the multi-layer web is passed between the sealing roller and the contact surface.
[0087] Preferably, the distance between the raised surface and the contact surface is less than 1 mm, preferably less than 0.4 mm, more preferably less than 0.1 mm.
[0088] Preferably, the distance between the bottom surface and the contact surface is greater than 1 mm, preferably greater than 1.5 mm, more preferably greater than 2 mm.
[0089] Preferably, said raised surface extends along the periphery of the absorbent sanitary article to be produced.
[0090] Preferably, the absorbent core of the absorbent sanitary article to be manufactured is positioned within said perimeter.
[0091] Preferably, the sealing rollers seal the topsheet web and the backsheet web around each absorbent core along said periphery.
[0092] Preferably, said bottom surface comprises a first region externally bounding said raised surface and a second region externally bounded by said raised surface.
[0093] The portion of the multi-layer web that contains the absorbent core of the absorbent sanitary article is located in the inner region.
[0094] Preferably, the second region is surrounded by a raised surface.
[0095] Preferably, the raised surface is surrounded by the first region.
[0096] Preferably, a raised region separates the first region from the second region.
[0097] Preferably, the contact roller and the sealing roller have approximately equal dimensions.
[0098] Preferably, the axis of rotation of the contact roller and the axis of rotation of the sealing roller are parallel and lie in a radial plane for both the contact roller and the sealing roller.
[0099] Preferably, there is a scraper adjacent the sealing roller.
[0100] Thus, continuous cleaning of the sealing roller during processing ensures uniform sealing of multi-layer webs and greatly reduces the need for machine downtime. The scraper is adjacent to the raised surface of the sealing roller to allow cleaning of the raised surface without damage.
[0101] Preferably, the scraper contacts the raised surface.
[0102] Preferably, a scraper is provided adjacent the contact roller. Thus, continuous cleaning of the contact roller during processing ensures uniform sealing of the multi-layer web and greatly reduces the need for machine downtime. The scraper is adjacent the contact surface of the contact roller to ensure damage-free cleaning of the contact surface.
[0103] Preferably, the scraper contacts the contact surface.
[0104] Preferably, the top sheet web and / or the back sheet web and / or the absorbent core are made of biodegradable materials. Thus, the multi-layer web of the absorbent hygienic article is at least partially biodegradable.
[0105] Preferably, the adhesive is a biodegradable adhesive. In this way, a biodegradable absorbent sanitary article can be produced.
[0106] Further features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments and the accompanying drawings, which are given by way of non-limiting examples. [Brief description of the drawings]
[0107] [Figure 1] 1 is a schematic diagram of part of an apparatus for producing absorbent sanitary products according to the invention; [Figure 1A] FIG. 2 is a different schematic view of the device of FIG. 1. [Diagram 2] FIG. 2 is a schematic perspective view of another part of the device according to the invention; [Diagram 3] 3 is a schematic front view of another part of FIG. 2 of the device according to the invention; FIG. [Figure 4A] FIG. 1 is an exploded perspective view of an absorbent sanitary product produced by the apparatus of the present invention. [Figure 4B] 4B is a schematic cross-sectional view of the absorbent sanitary article of FIG. 4A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0108] In Figures 1 to 3, reference number 100 designates an apparatus for producing absorbent sanitary products according to the invention.
[0109] Non-limiting examples of absorbent sanitary products that may be produced by the apparatus 100 include feminine sanitary napkins, infant diapers, incontinent diapers and pads, and the like.
[0110] In the following, without any loss of generality, a specific example of an absorbent sanitary product as shown in Figures 4A and 4B with reference number 10 will be specified. This example is specifically a feminine sanitary napkin. In the following description, this example is still equally applicable to various types of absorbent sanitary products.
[0111] Along its longitudinal axis A, the article 10 has a front portion 10a, a rear portion 10b, and a central portion 10c disposed between the front portion 10a and the rear portion 10b.
[0112] The article 10 includes a top sheet 12 and a back sheet 14. Both the top sheet 12 and the back sheet 14 have a generally rectangular shape with two opposing lower sides that are convexly rounded and two opposing longer sides that are concavely rounded. At the center of each of the two opposing longer sides of the top sheet 12 and the back sheet 14 are fastening flaps 13, 15 that extend from the longer sides in a direction transverse to the longitudinal axis A.
[0113] The topsheet 12 and the backsheet 14 define the inner and outer surfaces of the article 10, respectively.
[0114] The article 10 can be worn by applying the first adhesive portion 16 located on the backsheet 14 to the inside of an undergarment and folding the two opposing flaps 13, 15 to the outside of the undergarment and securing them to the undergarment by their respective second adhesive portions (not shown).
[0115] The top sheet 12 is overlapped with the back sheet 14 and is configured to be positioned facing the body of the wearer when the article 10 is placed in an undergarment.
[0116] The top sheet 12 is made of a fluid-permeable material. The back sheet 14 includes a layer that is substantially fluid-impermeable. In particular, the top sheet 12 and the back sheet 14 are made of a biodegradable material, preferably cellulose fibers. A liquid containment substrate (not shown) made of a water-soluble material (not shown), for example polyvinyl alcohol, is applied to the back sheet.
[0117] The absorbent core 18 is disposed between the top sheet 12 and the back sheet 14. The absorbent core 18 has a function of absorbing body fluids that pass through the top sheet 12 and retaining the body fluids without leaking for even several hours. The absorbent core 18 is made of an absorbent material including a fiber matrix of, for example, cellulose, and an absorbent powder (SAP) based on, for example, carboxymethylcellulose (CMC) dispersed in the fiber matrix. Thus, the absorbent core 18 is biodegradable. The absorbent core 18 has a generally elliptical shape that extends in the longitudinal direction from the front portion 10a to the rear portion 10b and is narrowed at the central portion 10c.
[0118] 1 to 3 show several parts of an apparatus 100 making it possible to manufacture an absorbent sanitary product 10.
[0119] The apparatus 100 comprises a forming unit 190 configured to form a multi-layer web 30 of an absorbent sanitary article 10. The multi-layer web 30 comprises a top sheet web 112, a back sheet web 114 and a plurality of absorbent cores 18 arranged in succession between the top sheet web 112 and the back sheet web 114. In a continuous process, the multi-layer web 30 is cut into individual elements each corresponding to a single absorbent article 10, such that the top sheet 12 of the absorbent article 10 is obtained from the top sheet web 112 and the back sheet 14 of the absorbent article 10 is obtained from the back sheet web 114 with one of the absorbent cores 18 arranged between the top sheet 12 and the back sheet web 114.
[0120] In the non-limiting example of Figure 1, the forming unit 190 includes a forming drum 192 rotatable about a rotation axis X. The forming drum 192 has an outer surface 193 which is preferably suctioned.
[0121] The forming drum 192 is configured to rotate in a direction D1 (counterclockwise in FIG. 1) to advance the outer surface 193 along a forming path.
[0122] The forming unit 190 is configured to deliver the top sheet web 112 directly to the forming drum 192 , and in particular to the outer surface 193 .
[0123] The first adhesive dispenser 194 is configured to dispense a liquid adhesive, preferably water-based, onto the top sheet web 112 before the top sheet web 112 is fed to the forming drum 192 to impregnate the top sheet web 112 with the adhesive.
[0124] 1, the forming unit 190 includes a transport drum 195 (only a portion of which is shown) that transports the absorbent cores 18. The transport drum 195 is configured to hold a plurality of absorbent cores 18, preferably by suction, and to rotate about its rotation axis (not shown) to feed the absorbent cores 18 in a direction D2 (clockwise in FIG. 1) opposite to the direction D1 of the forming drum.
[0125] The transport drum 195 is substantially in contact with the forming drum 192 and is configured to place the absorbent core 18 on the forming drum 192 so that the absorbent core 18 overlaps the top sheet web 112 .
[0126] The forming unit 190 is configured to supply the back sheet web 114 to a forming drum 192, thereby overlapping the back sheet web 114 with the top sheet web 112 and the absorbent core 18 overlapped therewith. In this manner, the multi-layer web 30 is formed with the absorbent core 18 disposed between the top sheet web 112 and the back sheet web 114.
[0127] The second adhesive dispenser 196 is configured to dispense a liquid adhesive, preferably water-based, onto the back sheet web 114 before the back sheet web 114 is fed to the forming drum 192 to impregnate the back sheet web 114 with the adhesive.
[0128] In an alternative embodiment of the invention not shown, only one of the first adhesive dispenser 194 and the second adhesive dispenser 196 may be provided such that only one of the top sheet web 112 and the back sheet web 114 is impregnated.
[0129] The support drum 200 is adjacent to the forming drum 192 substantially in contact with it. The support drum 200 is rotatably mounted to a frame 201 shown in FIG. 1A. The support drum 200 has a support surface 202. The support surface 202 is defined on an outer cylindrical surface of the support drum 200. The support surface 202 is preferably smooth and free of obvious humps, holes, or other surface irregularities.
[0130] The support drum 200 is rotatable about a rotation axis Y. The rotation axis Y is parallel to the rotation axis X. The support drum 200 is configured to rotate in a direction D3 (clockwise in FIG. 1) opposite to the direction D2.
[0131] 1, the forming drum 192 is disposed above the support drum 200. The diameter of the forming drum 192 is smaller than the diameter of the support drum 200.
[0132] The forming drum 192 is configured to feed the multi-layer web 30 to the support drum 200. The multi-layer web 30 is fed in a direction D1 on a forming surface 193 of the forming drum 192 and passed between the forming drum 192 and the support drum 200. When the multi-layer web 30 reaches between the forming drum 192 and the support drum 200, the multi-layer web 30 is dropped by the forming drum 192 and passed to the support drum 200, for example by ceasing the suction action on the forming surface 193.
[0133] The multi-layer web 30 is fed onto a support surface 202 in a direction D3.
[0134] The apparatus 100 includes a first compression roller 210 adjacent to the support drum 200 and configured to press the multi-layer web 30 against a support surface 202. The first compression roller 210 has a smooth cylindrical outer surface 212 and thus is free of humps, holes, or other obvious surface irregularities. Preferably, the cylindrical outer surface 212 corresponds to the entire side of the first compression roller 210.
[0135] The first compression roller 210, preferably in an idle state, is rotatably mounted on a first support body 213 (see FIG. 1A ). The first compression roller 210 is rotatable about a first axis of rotation W that is parallel to the axis of rotation Y of the support drum 200. The first compression roller 210 is configured to rotate about the first axis of rotation W in a direction D4 opposite to the direction D3 of the support drum 200 (which is a counterclockwise rotation in FIG. 1 ).
[0136] Preferably, the first support body 213 is connected to a first adjustment member 214 (see FIG. 1A ) configured to allow adjustment of the position of the first compression roller 210 relative to the support drum 200. The first adjustment member 214 may include a threaded member, such as a bolt and a nut. The first adjustment member 214 is configured to allow the position of the first compression roller 210 to be adjusted in a direction perpendicular to the support surface 202. This direction is radial to the rotation axis Y of the support drum 200.
[0137] The apparatus 100 comprises a scraper 215 configured to scrape the cylindrical outer surface 212 to remove adhesive residue and / or fibers. The scraper 215 is attached to the first support body 213 and has a free end in sliding contact with the cylindrical outer surface 212.
[0138] The first compression roller 210 is positioned at a first distance G1 from the support surface 202. The first distance G1 defines a gap between the support drum 200 and the first compression roller 210 through which the multi-layer web 30 passes. The first distance G1 is adjustable by a first adjustment member 214. In a preferred embodiment, the first distance G1 is equal to about 1.7 mm.
[0139] The multi-layer web 30 is advanced, particularly by rotation of the support drum 200, on a support surface 202 and passed between the support surface 202 and a first compression roller 210 so as to be compressed therebetween. Compression of the multi-layer web 30 enhances adhesion between the individual adhesive-impregnated layers of the multi-layer web 30.
[0140] The apparatus 100 includes a second compression roller 220 disposed adjacent to the support drum 200 and downstream of the first compression roller 210 with respect to the rotation direction D3 of the support drum 200. The second compression roller 220 is configured to press the multi-layer web 30 against the support surface 202. The second compression roller 220 has a smooth cylindrical outer surface 222 and is therefore free of lumps, holes, or other obvious surface irregularities. Preferably, the cylindrical outer surface 222 corresponds to the entire side surface of the first compression roller 210. In the non-limiting example shown in FIG. 1, the first compression roller 210 and the second compression roller 220 have approximately the same diameter.
[0141] The second compression roller 220, preferably in an idle state, is rotatably mounted on a second support body 223 (shown in FIG. 1A ). The second compression roller 220 is rotatable about a second axis of rotation J parallel to the axis of rotation Y of the support drum 200. The second compression roller 220 is configured to rotate about the second axis of rotation J in a direction D5 opposite to the direction D3 of the support drum 200 (counterclockwise in FIG. 1 ).
[0142] Preferably, the second support body 223 is connected to a second adjustment member 224 configured to allow adjustment of the position of the second compression roller 220 relative to the support drum 200. The second adjustment member 224 may include a threaded member, such as a bolt and a nut. The second adjustment member 224 is configured to allow the position of the second compression roller 220 to be adjusted in a direction perpendicular to the support surface 202. This direction is radial to the rotation axis Y of the support drum 200.
[0143] The apparatus 100 comprises a scraper 225 configured to scrape the cylindrical outer surface 222 to remove adhesive residue and / or fibers. The scraper 225 is attached to the second support body 223 and has a free end in sliding contact with the cylindrical outer surface 222.
[0144] The second compression roller 220 is positioned at a second distance G2 from the support surface 202. The second distance G2 defines a gap between the support drum 200 and the second compression roller 220 through which the multi-layer web 30 passes. The second distance G2 is adjustable by a second adjustment member 224. The second distance G2 is less than the first distance G1. In a preferred embodiment, the second distance G2 is equal to about 1.5 mm.
[0145] The multi-layer web 30 traveling on the support surface 202 is first passed between the support surface 202 and the first compression roller 210, and then between the support surface 202 and the second compression roller 220, thereby gradually compressing the web 30 and improving adhesion between the individual adhesive-impregnated layers of the multi-layer web 30, thereby reducing adhesive leakage.
[0146] In an alternative embodiment of the invention (not shown), the two compression rollers 210 and 220 may be replaced by a single compression roller.
[0147] The apparatus 100 is configured to allow the multi-layer web 30 to leave the support surface 202 downstream of the second compression roller 220 and move along a forward path to undergo subsequent processing.
[0148] The apparatus 100 comprises downstream of the support drum 200 a sealing station 230, shown in Figures 2 and 3. Optionally, further processing stations may be arranged along the forward advance path of the multi-layer web 30 between the support drum 200 and the sealing station 230.
[0149] The sealing station 230 seals the topsheet web 112 and the backsheet web 114 around each absorbent core 18 of the multi-layer web 30 .
[0150] 2 and 3, the multi-layer web 30 is fed to the sealing station by a conveyor belt 240. The conveyor belt 240 can be configured to receive the multi-layer web 30 from a support drum 200, for example.
[0151] The sealing station 230 includes a sealing roller 232 facing a contact roller 234 .
[0152] The sealing roller 232 rotates about a rotation axis L in a direction D6 (clockwise in FIG. 3).
[0153] The contact roller 234 rotates about a rotation axis M parallel to the rotation axis L in a direction D7 (counterclockwise direction in FIG. 3) opposite to the direction D6 of the sealing roller 232.
[0154] In the non-limiting example shown in FIG. 3, the rotation axes L and M lie in a substantially perpendicular trace plane V1.
[0155] The contact roller 234 is disposed substantially tangent to the sealing roller 232, except through the thickness of the portion of the multi-layer web 30 being sealed. The axes of rotation L and M lie in a radial plane for both the contact roller 234 and the sealing roller 232.
[0156] In the non-limiting example shown in FIG. 3, the sealing roller 232 and the contact roller 234 have approximately the same outer diameter.
[0157] The contact roller 234 defines a smooth contact surface 234a on its outer cylindrical surface.
[0158] The sealing roller 232 has a cylindrical bottom surface 232a defined at a first radial distance G3 from the axis of rotation L and a smooth raised surface 232b defined at a second radial distance G4 from the axis of rotation L that is greater than the first radial distance G3 (FIG. 3).
[0159] The sealing roller 232 is pressed against the contact roller 234 such that the smooth raised surface 232b presses against the smooth contact surface 234a.
[0160] Referring to FIG. 2, the raised surface 232b extends around the periphery of the absorbent sanitary product being produced such that as the multi-layer web 30 passes between the sealing roller 232 and the sealing roller 234, the raised surface 232b presses against areas in the multi-layer web 30 that include the overlapping top sheet web 112 and back sheet web 114 but not the absorbent core 18.
[0161] The bottom surface 232a includes a first region 232c outboard of the raised surface 232b. The first region 232c extends outboard of the perimeter along which the raised surface 232b extends.
[0162] The bottom surface 232a includes a second region 232d bounded by the raised surface 232b. The portion of the multi-layer web 30 that will include the absorbent core 18 of the absorbent sanitary article 10 to be manufactured is operably positioned within the inner region 232d such that the portion is not pressed against the contact surface 234a by the raised surface 232b.
[0163] The raised surface 232b is configured to seal the top sheet web 112 and the back sheet web 114 around the absorbent core 18 by pressing the top sheet web 112 and the back sheet web 114 against the contact surface 234a.
[0164] The apparatus 100 includes a scraper 235 adjacent the contact surface 234a for cleaning the contact surface 234a without damaging it.
[0165] The device 100 further comprises a scraper 233 adjacent to the raised surface 232b for cleaning the raised surface 232b without damage. In addition, near the scraper 233, a suction duct 237 is provided adjacent to the raised surface 232b, configured to suck excess adhesive and processing residues.
[0166] It is obvious that those skilled in the art can make various modifications and variations to the invention described above according to their specific needs, within the scope of protection defined by the appended claims.
Claims
1. An apparatus (100) for manufacturing absorbent sanitary products (10), comprising: A smooth support surface (202); a forming unit (190) configured to form a multi-layer web (30) of an absorbent sanitary article (10) including a top sheet web (112), a back sheet web (114), and a plurality of absorbent cores (18) disposed between said top sheet web (112) and said back sheet web (114), said forming unit (190) configured to supply said multi-layer web (30) to said support surface (202); at least one adhesive dispenser (194, 196) configured to dispense liquid adhesive onto said back sheet web (114) and / or said top sheet web (112); at least one compression roller (210, 220) adjacent to said support surface (202) and configured to press said multi-layer web (30) against said support surface (202), said at least one compression roller (210, 220) having a smooth cylindrical outer surface (212, 222); An apparatus (100).
2. The apparatus (100) of claim 1, wherein the at least one compression roller (210, 220) is mounted at a respective adjustable distance (G1, G2) from the support surface (202).
3. The apparatus (100) of claim 1 or 2, comprising a scraper (215, 225) adjacent the outer cylindrical surface (212, 222) of the at least one compression roller (210, 220).
4. 2. The apparatus (100) of claim 1, wherein the at least one compression roller (210, 220) comprises a first compression roller (210) and a second compression roller (220), the second compression roller (220) being disposed adjacent the support surface (202) and downstream of the first compression roller (210).
5. 5. The apparatus (100) of claim 4, wherein the first compression roller (210) is mounted at a first distance (G1) from the support surface (202) and the second compression roller (220) is mounted at a second distance (G2) from the support surface (202) that is less than the first distance (G1).
6. The apparatus (100) of claim 1, wherein the apparatus (100) comprises a support drum (200), and the support surface (202) is defined on an outer cylindrical surface of the support drum (200).
7. a smooth contact surface (234a) configured to receive the multi-layer web (30) downstream of the support surface (202); a sealing roller (232) adjacent said contact surface (234a), said sealing roller (232) having a cylindrical bottom surface (232a) defined at a first radial distance (G3) from an axis of rotation (L) of said sealing roller (232) and a smooth raised surface (232b) defined at a second radial distance (G4) from said axis of rotation (L) that is greater than said first radial distance (G3); Equipped with The apparatus (100) of claim 1, wherein the sealing roller (232) is pressed against the contact surface (234a).
8. 8. The device (100) of claim 7, wherein the raised surface (232b) extends along the periphery of the absorbent sanitary product (10) to be manufactured, and the bottom surface (232a) includes a first region (232c) that defines from the outside the boundary of the raised surface (232b) and a second region (232d) whose boundary is defined from the outside by the raised surface (232b).
9. A method for producing an absorbent sanitary article (10), comprising the steps of: forming a multi-layer web (30) for an absorbent sanitary article (10) comprising a top sheet web (112), a back sheet web (114), and a plurality of absorbent cores (18) disposed between said top sheet web (112) and said back sheet web (114); providing said multi-layer web (30) onto a smooth support surface (202); dispensing a liquid adhesive onto said back sheet web (114) and / or said top sheet web (112); compressing the multi-layer web (30) between at least one compression roller (210, 220) having a smooth cylindrical outer surface (212, 222) and the support surface (202); A method comprising: