WO2009117794A1

WO2009117794A1 - Process of manufacturing a multilayer absorbent product and product obtained

Info

Publication number: WO2009117794A1
Application number: PCT/BR2009/000081
Authority: WO
Inventors: Vicente Oscar Espinoza Camino
Original assignee: Wagner Do Brasil Ltda
Priority date: 2008-03-24
Filing date: 2009-03-24
Publication date: 2009-10-01
Also published as: WO2009117794A4

Abstract

comprises the use of pressure exerted between a rigid metallic roller, endowed with hollow holes (the desired pattern to be imprinted), and a roller of flexible material. Due its flexible constitution, the nonmetallic roller pressures areas of the paper - or stack of sheets of paper- into the holes of the rigid metallic roller. A smooth sheet of paper is glued over and compressed against the paper layer thus formed, while the last one still has areas inside the holes of the rigid roller. In consequence, the smooth sheet only adheres to the areas of the paper that are outside the holes of the rigid roller, imprisoning air between the paper layer introduced in said holes and the external sheet applied on it. The result is an embossed multilayer absorbent product with imprisoning air bubbles that presents the same pattern imprinted in the metal roller.

Description

PROCESS OF MANUFACTURING A MULTILAYER ABSORBENT PRODUCT AND PRODUCT OBTAINED Field of the invention

The present invention refers to the technological field of absorbent products and relates, more specifically, to a process of manufacture of a multilayer absorbent product and the resultant product, in which the absorbent material is composed for an upper layer of absorbent paper sheets submitted to an embossing process by rollers that engrave figures in relief, joined to a sheet or set of sheets, preferentially of paper (permeable or not) forming a base layer whose external surface can contain adhesive, totally of partially covered for a removable film, as a ribbon of silicon paper.

The product thus obtained can be used in several applications: If the external surface of the base layer contains adhesive, totally of partially covered for a removable film, as a ribbon of silicon paper, the product could be used as daily pant protector, protector for breast-feeding, absorbent for bladder dysfunction, bib or any other article where partial or total attachment to a surface or object is necessary.

If the external surface of the base layer does not contain adhesive, the product could be used in any application where the attachment to a surface or object is not necessary, as tray cover, cup rest, dismissible towels, bibs for dentists, envelopes for fragile products and a multiplicity of other products.

Background of the invention

The known state of art of this technological field refers to any manufacturing process of absorbent products and the products themselves. Today the existing processes to manufacture multilayer products generally comprise the union of one or more sheets as described, for example, in the Brazilian patent application BRPI8203870, also filled for Kimberly-Clark Corporation in USA as US4487796, "Laminated, Creped Tissue and Method of Manufacture". This patent described a method of laminating a two-ply product wherein the first ply is directed for a patterned pressure and imprinting roll and laminating adhesive is applied to the first ply in a pattern corresponding to the pattern of the pressure roll. A second ply is brought into contact with the first ply, and the composite web is adhered to a creping surface with creping surface with a creping adhesive at a nip formed between the creped surface and the patterned pressure roll, forming the laminated product. It's important to say that is a very complex manufacturing process, with a great number of steps that must be done to accomplish the final result and that the resultant product is smooth, without any relief in the outside surface, because the empty spaces produced for the rolls are disposed in the inside between the layers.

Another patent application cited is BRPI0509162-3, filled in USA as US2007/017627, "Apparatus for and process of manufacturing a multi-ply absorbent paper product and product thus obtained" that describes an apparatus for producing a multi-ply absorbent paper product that includes a first embossing unit, having a first and second embossing roller that are couple and suitable for embossing and associating together at least one first ply of paper and at least one second ply of paper, also comprising one second embossing unit separate from the first and having at least one third embossing roller coupled with a forth embossing roller for embossing at least one third ply of paper and associating it with the first or second ply of paper. These rollers must follow high precision standards what means elevated costs for manufacture of the same. Additionally the rollers must be perfectly synchronized in the equipment so that the saliencies in each roller accurately apply pressure in the same points and propitiate the union of the paper layers. This problem of synchronism is common to all the processes and equipments of the known state of art, because the use of a pair of rollers, one endowed in its surface with positive shapes and another with negative shapes, or both with positive shapes, or both with negative shapes, implies a precise synchronism to obtain a coincidence of the points where the pressure is applied to emboss the desired pattern.

Part of the novelty of the current invention is due to the fact that there is not any process in the state of art that aloud the union of a sheet of paper (or pile of sheets) in relief (embossed with a pattern) with a smooth base (or sheet) with a plain surface.

Nowadays the absorbent products for external use, as daily protectors for panties, breast protectors for breast-feeding, hygienical absorbents, diapers for babies and adults and others, are always compose for:

- A polymeric layer that allows the passage of organic fluid and retains excrements;

- An absorbent core that retains the organic fluids that crossed the first layer. That core is composed for hydrophilic cotton, absorbent pulp of cellulose and/or polymeric materials;

- A structural support layer.

The main element that all of these articles have in common is the polymeric layer (made of non woven fabrics or nylon or rayon), whose function is conduct the body fluids into the inside of the core layer (generally composed for cellulose fibers). The external surface that is attached to the clothes of the user is constituted by a polyethylene film or for the same material of the polymeric layer, acting like a structural support. In general, the union of these layers is obtained through external edges adhered by appliance of heat and pressure. Another alternative used to obtain this union is making the polymeric layer surround the core layer and being glue in the rear face of the article. These conventional absorbent products have two main drawbacks. The first problem, that is mainly an ecological issue, is what to do with the articles after the use. Some of the materials of synthetic origin (polypropylene, polyethylene, nylon), currently used in the confection of the cited articles, bring serious damages to the environment and must be discharged carefully. The second, but not less important problem is a matter of hygiene and health for the users. These materials, in contact with the skin, can cause irritations and, since they do not allow an adequate perspiration, can create a propitious environment for the proliferation of bacteria and other biological hazards. This problem is well documented in medical literature and is a frequent reason of complaints in doctor's offices. Summary of the invention

The current invention was developed to solve all the drawbacks of the state of art and relates to a manufacturing process of a multilayer absorbent product and the resultant product.

The process of manufacture disclosed in the present report refers to a process for obtaining a multilayer paper product that comprises a new solution for the union of the paper layers. The current invention uses the pressure exerted between a rigid metallic roller, endowed with hollow holes (the desired pattern to be imprinted), and a roller of flexible material. Due its flexible constitution, the nonmetallic roller pressures areas of the paper - or stack of sheets of paper- into the holes of the rigid metallic roller. A smooth sheet of paper is glued over and compressed against the paper layer thus formed, while the last one still has areas inside the holes of the rigid roller. In consequence, the smooth sheet only adheres to the areas of the paper that are outside the holes of the rigid roller, imprisoning air between the paper layer introduced in said holes and the external sheet applied on it. The result is an embossed multilayer absorbent product with imprisoning air bubbles that presents the same pattern imprinted in the metal roller.

The described process eliminates the use of the expensive precision metallic rollers that were used until now and doing so obtains decrease of the manufacture costs of the absorbent articles. It also eliminates the need of perfect synchronism between the rollers and all the technical difficulties related to the maintenance of this synchronism, making the manufacture process simpler and easier.

It's also revealed for the first time a manufacturing process that results in an absorbent paper article formed for a layer of embossed paper adhered to a smooth plain base sheet, what it is not possible using the conventional processes. The resultant absorbent product could be useful in several applications where resistance, comfort, impermeability, liquid or humidity absorption, capacity of aeration and other properties of the same are desired or necessary, including, but not limited to, articles of personal care, since its composition is not allergic to the user skin, it not favors the proliferation of pathogenic agents (it makes perspiration easier) and is not aggressive to the environment (it can be discarded without further problems). Brief description of the drawings

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

Figure 1 is a schematic representation of the manufacturing process proposed for the current invention. Figure 2 is an amplified detail of the rigid embossing roller.

Figure 3 is a cross sectional view of the absorbent product.

Detailed description of the invention The invention is herein described, by the way of example only, with reference to the accompanying drawings. With specific reference now to the figures 1 and 2, we can see that in the manufacturing process of a multilayer absorbent product one sheet or several sheets of paper (1) are unrolled and grouped, forming a stack of sheets with faces A and B, that is passed through two compressing rollers (2) and (3), whose purpose is to join the sheets of paper (1 ) and to emboss figures in relief in the formed stack of papers. The first roller (2) is rigid and metallic being endowed with hollow holes (4) shaped with the pattern that it is desired to emboss the papers, while the second roller (3) is smooth and flexible, so it can compress the sheets of paper (1) into the hollow holes (4). One sheet or stack of sheets (5) is directed into opposite direction of the movement of the sheets passing through the rollers (2 and 3). These grouped sheets (5) are unrolled simultaneously to the sheets (1) and receives a layer of adhesive (6) to be glued to the sheets (1 ) that leave the rollers (2) and (3). Pressure is applied on the roller (2) for a roller (7), obtaining union of the sheets (5) over the embossed sheets (1 ) only in the available points of contact of face B. That means the areas of the sheets (1) that were not introduced into the hollow holes (4) of the roller (2). The result of this procedure is that on face A the pattern of the roller (2) will be salient (8), imprisoning air inside (9) and closing the lower face (10) of the article with the sheet or stack of sheets (5) that will remains smooth and plain. The product thus resultant (11) has a soft upper surface, capable of a good absorption of liquids, since there is air encapsulated between the upper layer (1) and the lower sheets (5).

According to another embodiment of the present invention, it is also possible to sprinkle adhesive (12) over the sheets

(1) before the same reach the rollers (2) and (3), in order to obtain a better adhesion of the papers of the stack, depending on the desired use of the absorbent product.

According to another embodiment of the present invention, depending on the final use of the material manufactured, it can be desirable that the lower face of the sheet (5) receives adhesive

(13) and be protected by a not adherent film, as silicon paper, or receiver another waterproofed protection.

As we can see in detail in the figure 3, the resultant product (11) of the above described manufacturing process it is formed by a layer of one or more sheets of paper (1) with a outer salient pattern (8) that imprisoned air inside (9), joined to a smooth layer of one or more sheets (5), that can alternatively be endowed with external adhesive (13) re-covered by a not adherent film, as silicon paper or another waterproof mean. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1- Process of manufacturing a multilayer absorbent product comprising the steps of: a) Unroll one or several sheets of paper (1) and group the same, forming a stack of sheets with faces A and B; b) Pass the sheets (1) through one rigid roller (2) endowed with hollow holes (4) and a flexible smooth roller (3) to compress the sheets of paper (1 ) into the hollow holes (4); c) applied a sheet or stack of sheets (5) covered with adhesive over the embossed papers (1 ) pressing a roller (7) on the roller (2).

2- The process of manufacturing of claim 1 wherein said step of applied a sheet or stack of sheets (5) to the embossed papers (1) includes unroll the sheets (5) simultaneously to the sheets (1) and direct these sheets (5) into opposite direction of the movement of the sheets passing through the rollers (2 and 3);

3- The process of manufacturing of claim 1 wherein alternatively sprinkles adhesive (12) over the sheets (1) before the same reach the rollers (2) and (3); 4- The process of manufacturing of claim 1 wherein alternatively the lower face of the sheet (5) receives adhesive (13) and is covered by a not adherent film;

5- The process of manufacturing of claim 4 wherein the not adherent film is silicon paper; 6- The process of manufacturing of claim 4 wherein the adhesive face (6) of sheets (5) is turned waterproof;

7- Multilayer absorbent product comprising a layer of one or more sheets of paper (1) with a outer salient pattern (8) that imprisoned air inside (9), joined to a smooth layer of one or more sheets (5);

8- Multilayer absorbent product of claim 7 endowed with external adhesive (13) re-covered by a not adherent film;

9- Multilayer absorbent product of claim 7 wherein the not adherent film is silicon paper;

10- Multilayer absorbent product of claim 7 wherein the stack of paper (5) is turned waterproof.