WO2005060891A1

WO2005060891A1 - Liquid absorbing sheet

Info

Publication number: WO2005060891A1
Application number: PCT/BR2004/000229
Authority: WO
Inventors: Ricardo Junqueira Franco
Original assignee: Ricardo Junqueira Franco
Priority date: 2003-12-23
Filing date: 2004-11-23
Publication date: 2005-07-07
Also published as: BR0305832A

Abstract

Liquid absorbing sheet, comprising a first inferior layer defined as a flexible structural base made of an impermeable plastic film (1), with variable thickness and dimensions, but, independently of such aspects, the upper side receives a thin adhesive layer (2), applied through any convenient mean, forming a adherent surface strong enough to hold another upper layer of a different material, defined as super absorbent granules (3) that will finally be covered with a last stabilizing layer of non-woven fabric (4) concluding a super absorbent sheet for different applications.

Description

LIQUID ABSORBING SHEET Invention Field Particularly, the present Invention refers to technical and functional improvements specially developed to be characterized as an absorbent sheet for industrial or commercial use, as well as hospitals (humane) or other fields that require the use of a stretched sheet over any kind of surface to absorb and control determined liquids that may somehow leak or flow undesirably, for example, over hospital beds, inside transport/freight vehicles, be it terrestrial, aerial or maritime, among other ones. Technical State As common knowledge for experts in this field, there are many products, materials, means and compositions to absorb liquids. Some of the most famous and traditional products are disposable diapers and feminine hygienic pads. Besides, there are absorbent food pads, usually used in trays with meat, fruits, cheeses, etc, in supermarkets. Moreover, we can take into account the urine sheets for hospitals, pets, among other ones. So, the absorbent sheets aim to eliminate undesirable excessive liquids that may contaminate, harm or simply wet or soak places or objects that cannot or should not be exposed to water or humidity and that must stay dry and clean. Odors and contaminations can also be avoided. For each application, common sheets are manufactured with different characteristics according to its use and area to be protected, consequently, dimensional factors, as well as components quality, suffer profound variation. However, in general, they are all manufactured obeying a certain constructive standard, once the product must be constituted of two basic parts: a impermeable inferior base, substantially flexible, working as sheet structure and main barrier for liquid retention. The absorbing layers stay over this barrier or structure. Thus, briefly, we can say that common sheets are composed of different layers, as follows: a) an impermeable laminated plastic film, forming the mounting base and works as a barrier to refrain liquids from leaking or going through the sheet; b) a layer of adhesive applied over the plastic film; c) over the side of the plastic film with, adhesive, a layer of grounded cellulose fluff pulp is placed, composing the liquid absorbing and retaining layer; d) the fluff pulp layer may be mixed with a certain amount of super absorbent polymer (SAP - polyacrylate granules) to improve the absorbent capacity of the sheet, because the SAP increases the capacity to absorb and retain liquids. e) another optional component is paper tissue on the top of it, similar to toilet paper, stabilizing the other layers and improving absorption and liquid distribution of the whole. f) Moreover, optionally a last laminated plastic film can be placed over the whole with structural flexible effect, but, in this case, the film has to be extremely permeable with holes or orifices to allow absorption and penetration of liquids. A permeable non-woven fabric, that looks like traditional fabric, can substitute this last layer. This layer will adhere to the first plastic layer thanks to the adhesive applied over the plastic film. So, the traditional absorbing sheets are composed, in general, of many layers of different products, where liquids are absorbed e retained inside the sheet up to the limit of total capacity of the raw materials used. The proportion, dimensions and shapes of each element of the product are variable according to each need. In the same way, the technical specifications of the raw materials are variable, selected and determined according to multiple factors, like: final purpose, product type, absorption capacity required, safety against leaks, resistance, etc. In the same way, the typology of the plastic film (chemical composition, thickness, color, etc) and other components may vary according to the required objectives. These sheets are used as much as needed to absorb, dry or protect surfaces, objects or anything, according to user need, and are generally discarded. No doubt that the common sheets can achieve its objectives during utilization, however, there are some noticeable disadvantages not related to its absorbency efficiency of the whole, but related to manufacturing costs, volume and product handling, because for specific uses in the industry, commerce, hospitals like freight airplanes, where the sheet is substantially big and shall have certain specific characteristics. So, the sheet shall absorb a certain amount of liquids, but also, respect other important specifications, like weight, volume and final cost, what doesn't happen with common sheets. OBJECTIVES OF THE INVENTION Make concrete an absorbing sheet for use in the industry, commerce, hospitals and/or other fields and activities that require the use of a stretched sheet over any surface or object to absorb and control certain liquids that may leak or flow undesirably, as it happens, for example, inside some freight vehicles, be it aerial, terrestrial or maritime, but also, achieving other objectives and advantages. So, we created an absorbent sheet, eliminating one of the main components, that is the cellulose fluff pulp, and combining the use of glue, herein technically denominated "adhesive", with distribution, placement and adhesion of super absorbent granules over the plastic film. This new composition shows the following technical characteristics: an impermeable plastic film; a layer of adhesive; super absorbent granules; a possible layer of non-woven fabric, plastic film or tissue paper; and finally, a permeable plastic film or non- oven fabric. Thus, over the impermeable plastic film, it is applied a layer of adhesive specially designed for its purpose (usually, it is used hot- melt adhesive, with instant adhesion). The super absorbent granules are spread only in the desired specific places and where it is necessary to achieve its objective of absorption. The exact amount and place can be controlled. So, the super absorbent granules get imprisoned by the adhesive and only in desired, determined or specified places. Thus, the granules don't disperse, don't fall, don't get loose, don't contaminate the environment, don't accumulate in other places (for example, after handling) and follow other technical requirements. The granules in excess can be removed, during the manufacturing process by aspersion or other means. Over this layer of super absorbent granules, another layer of adhesive may be applied, to improve granule adhesion to the plastic film, or adhesion to a new layer of: tissue paper, perforated plastic or non-woven fabric. Concluding the process, a new final layer of perforated plastic film or won-woven fabric is adhered over the impermeable plastic film, initially used and placed. The sheet in question, with this construction and constitution, achieves all the objectives desired during utilization, not only about absorption efficiency, but also about manufacturing cost, volume and product handling, working perfectly with determined applications in the industry, commerce and humane, for example, hospitals, freight airplanes, where the sheets are substantially big and shall have certain peculiar characteristics, in other words, ideal to absorb a certain amount of liquid and also other important specifications, mainly weight, volume and final cost. This present improved sheet has all these benefits mentioned above. DRAWING DESCRIPTION For a better comprehension of the present Invention, see below a detailed description of it, with references to the attached drawings, where drawings 1 and 2 illustrate schematically the different layers and components of the present improved sheet, where the layers are illustrated with exaggerated dimensions for easy visualization. DETAILED DESCRIPTION OF THE INVENTION According to this illustration and its details, particularly the drawing 1, the present Invention, LIQUID ABSORBING SHEET, is characterized by one first inferior layer defined as structural flexible base formed by an impermeable plastic film (1), with variable thickness and dimensions, that receives a thin layer of adhesive (2) in the upper side, applied through convenient means, making the film surface adherent enough to hold another layer of a different material, defined as super absorbent granules (3) that is finally completely covered by a last stabilizing layer composed of a non woven fabric (4). In a first constructive variation, the non-woven layer can be substituted by a layer of plastic film with permeable means like orifices or any other way that accomplishes this function. The adhesive layer (2) can cover uniformly the plastic film surface completely or not, in other words, it can follow any pattern or range, as lines, dots or pre-determined areas. The same happens with the super absorbent granules layer because it may not follow the same area covered by the adhesive layer (2), since the adhesive layer is also important to bond other subsequent layers. Thus, the absorbent granules (3) may be applied to cover the whole surface of the plastic film (1) or cover only some desirable areas depending on the need, in the exact amount and predetermined places. So, the super absorbent granules stay bonded by the adhesive only in desired, determined or specified places. In this way, the absorbent granules will not disperse, fall or get loose in the sheet, contaminate the environment, get accumulated in certain places (during handling for example), and other possible issues. The granules in excess can be removed by aspersion or any other mean. In another constructive variation shown in drawing 2, over the super absorbent granules layer (3) is applied a new layer of adhesive, to increase the retention of granules and, if necessary, of another layer of paper tissue (4), perforated plastic film or non-woven fabric. Concluding the process, a new final layer of perforated plastic film or non-woven fabric is placed over the impermeable plastic film, initially used. If necessary, the sheet perimeter or at least two opposite sides can be properly sealed, by bonding, uniting, or folding the borders of the base (1) over the other layers. The sheets can be supplied in rolls or separately with predetermined dimensions. The sheet improved in this manner defines a unique construction comparing to common sheets, achieving all objectives during manufacture and use, not only regarding absorbency and function efficiency, but also manufacturing costs, volume and handling, perfect for determined applications in the industry, commerce, hospital (humane), for example, transport airplanes where the sheet is substantially big and shall have certain peculiar characteristics, in other words, ideal to absorb a certain amount of liquid, and also meet other important specifications, mainly weight, volume and final cost. The present improved sheet adds many technical and practical advantages, as mentioned below: 1) cost reduction: no use of cellulose fluff pulp, one of the most expensive components in common sheets. 2) reduction of technological operations: it is very complicated to transform cellulose sheets or rolls into minuscule fibers; 3) equipment reduction: there is no need to handle cellulose and spread it over the impermeable plastic film; 4) time reduction: the process is faster due to less manufacturing operations mentioned above; 5) investment reduction: the mills and machines to position the cellulose fluff pulp over the impermeable plastic film are expensive; 6) reduction in adhesive quantity use: the adhesive is applied in exact quantity and predetermined places, reducing costs and time of application. 7) Volume reduction: the volume of the sheet is substantially lower without cellulose fluff pulp, because the fluff fibers layer takes sometimes much more space than any other layer; 8) Weight reduction: without cellulose fluff pulp, the sheet becomes much lighter. 9) less weight results in less volume, turning the packages smaller and less expensive 10) weight reduction results in less freight costs because of weight and volume; 11) appearance - without cellulose fluff pulp the sheet becomes thinner, easier to handle and easier to be positioned in any place; 12) Layers are bonded stronger because the fluff pulp will not force or expand before and after absorbing liquids.

Claims

CLAIM

1 ) LIQUID ABSORBING SHEET, characterized by a first inferior layer defined as a flexible structural base formed by an impermeable plastic film (1), with variable thickness and dimensions, but, independently of such aspects, the upper side receives a thin adhesive layer (2), applied through any convenient mean, forming a adherent surface strong enough to hold another upper layer of a different material, defined as super absorbent granules (3) that will finally be covered with a last stabilizing layer of non- woven fabric (4);

2) LIQUID ABSORBING SHEET, according to claim 1 , by the fact that there is a first constructive variation where the non-woven fabric is substituted by a plastic film with permeable means that can be holes, orifices or any other way that achieves this functionality; 3) LIQUID ABSORBING SHEET, according to claim 1 , by the fact that the adhesive layer (2) covers uniformly the whole surface of the plastic film base (1);

4) LIQUID ABSORBING SHEET, according to claim 1 , by the fact that the adhesive layer (2) can cover only some pre-determined areas of the plastic film base (1);

5) LIQUID ABSORBING SHEET, according to claim 1, by the fact that the super absorbent granules cover the whole surface of the plastic film base

(i);

6) LIQUID ABSORBING SHEET, according to claim 1 , by the fact that the super absorbent granules can cover only some pre-determined areas of the plastic film base (1);

7) LIQUID ABSORBING SHEET, according to claim 1 , by the fact that there is another constructive variation where a new adhesive layer is applied over the super absorbent layer (3) in a way to hold a new layer of paper tissue (4), perforated plastic film or non-woven fabric and, a new final layer of perforated plastic film or non-woven fabric over this last layer, placed over the impermeable plastic film base initially used.

8) LIQUID ABSORBING SHEET, according to claim 1, by the fact that if necessary, the sheet perimeter or at least two opposite sides can be sealed adequately, by bonding, uniting, or folding the borders of the base (1) over the other layers.