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EP-4228971-B1 - A METHOD AND AN APPARATUS FOR PACKAGING ARTICLES

EP4228971B1EP 4228971 B1EP4228971 B1EP 4228971B1EP-4228971-B1

Inventors

  • Gualtieri, Diego
  • BLASIOLI, Renzo
  • RADOVANI, Asti
  • RODRIGUEZ, MARC
  • MATEU, JORDI
  • Lüttgens, Thomas

Dates

Publication Date
20260506
Application Date
20210611

Claims (8)

  1. A method for packaging plasters (A) comprising: - providing plasters (A) aligned and spaced apart from each other in a continuous array that advances in a machine direction (X) on an inlet conveyor (12), - feeding a first continuous flexible sheet (18) and a second continuous flexible sheet (20) towards an overlapping unit (22), wherein at least one of said sheets (18, 20) has a thermally-activated adhesive on its surface facing the other sheet, - in a first step enclosing said plasters (A) between said opposite continuous flexible sheets (18, 20) and forming a continuous composite tape (26) comprising two continuous flexible sheets (18, 20) superimposed on each other, and a continuous array of plasters (A) spaced apart longitudinally from each other and sandwiched between the two continuous flexible sheets (18, 20), the method being characterized by : - carrying out a preliminary heating of at least one of said sheets (18, 20) before enclosing said plasters (A) between said sheets (18, 20), - in a second step, distinct and separate from said first step, compressing said sheets (18, 20) to fix said sheets (18, 20) together around said plasters (A) by means of said thermally-activated adhesive, and carrying out a final heating of said at least one of said sheets (18, 20) simultaneously to compressing said sheets (18, 20).
  2. The method of claim 1, wherein at least one of said sheets (18, 20) is heated exclusively along areas of the sheet that are intended to be compressed and/or wherein said sheets (18, 20) are compressed exclusively around each of said plasters (A).
  3. The method of any of the preceding claims, wherein both said sheets (18, 20) are heated on the respective faces opposite to the faces intended to be facing towards said plasters (A).
  4. The method of any of the preceding claims, wherein at least one of the flexible sheets (18, 20) is kept in contact with a sector of the outer surface of a respective coupling roller (24) before said plasters are enclosed between the two opposite flexible sheets (18, 20), thereby heating up the flexible sheet (18, 20), wherein said sector has an angular extension comprised between 60° and 270°, preferably between 90° and 180°, in particular between 100° and 150°
  5. The method of any of the preceding claims, wherein said flexible sheets (18, 20) advance through the compression unit (28) at a speed of 150 - 250 m/min, in particular 180 - 210 m/min.
  6. An apparatus for packaging plasters (A) comprising: - an inlet conveyor (12) configured for advancing in a machine direction (X) a continuous array of plasters (A) aligned and spaced apart from each other, - a first feeding assembly (14) and a second feeding assembly (16) configured for feeding, respectively, a first continuous flexible sheet (18) and a second continuous flexible sheet (20) towards an overlapping unit (22) configured to apply the two flexible sheets (18, 20) on opposite sides of said plasters (A), so as to enclose said plasters (A) between said sheets (18, 20) to form a continuous composite tape (26) comprising two continuous flexible sheets (18, 20) superimposed on each other, and a continuous array of plasters (A) spaced apart longitudinally from each other and sandwiched between the two continuous flexible sheets (18, 20), - a preliminary heating unit (34, 36, 40) configured for heating at least one of said sheets (18, 20) before enclosing said plasters (A) between said sheets (18, 20), and - a compression unit (28) distinct and separate from said overlapping unit (22) and configured to compress said sheets (18, 20) at compression areas, and - a final heating unit configured for heating at least one of said sheets (18, 20) at said compression unit (28).
  7. The apparatus of claim 6, wherein said overlapping unit (22) comprises two coupling rollers (24) with respective axes parallel to each other and configured to apply said sheets (18, 20) on opposite sides of said plasters (A), wherein said preliminary heating unit (34, 36, 40) is arranged inside at least one of said coupling rollers (24).
  8. The apparatus of claim 7, wherein at least one of said coupling rollers (24) comprises one or more heating units (34, 36), wherein each of the heating units (34, 36) heats a sector of the coupling roller (24) having an angular extension comprised between 60° and 270°, preferably between 90° and 180°, in particular between 100° and 150°.

Description

Field of the invention The present invention relates in general to the packaging of plasters which are articles having a thickness lower than the other dimensions. More precisely, the invention relates to a method and an apparatus for forming packages comprising plasters enclosed between two opposite flexible sheets having their edges joined by means of a thermally-activated adhesive. The invention was thus developed with a view to its application in the field of packaging plasters, such as, for example, plasters for covering wounds, medicated plasters, pain-relieving plasters, heating plasters with and without medicaments. In the following description, reference will be made to this specific field of use without however losing generality. To be more specific, in the following description, the term "article" refers solely to plasters such as the examples listed above. Description of the prior art In the medical field there are different types of plasters. In many cases, these products are boxed without being wrapped. In some cases, the plasters are packaged individually in envelope-shaped packages before being boxed. Individual packaging of the plasters is carried out by enclosing the individual plasters between two flexible sheets overlapping each other that enclose a respective plaster like a sandwich, and are joined together at their edges by means of adhesive. Typically, in this field the adhesive used is a thermally-activated adhesive because it guarantees stable fixing of the sheets so that the articles are protected from external agents. Thanks to these thermally-activated adhesives, once the package is opened, it is no longer resealable, and this allows the health and hygiene standards relating to the marketing of plasters or other similar articles to be met. The packages may be formed by two sheets of paper or by a sheet of paper and by a sheet of plastic material, as well as by two sheets of plastic material. For example, the plastic material may be transparent such as polyethylene. Often the packages of plasters are formed by a sheet of paper having an outer surface on which information relating to the product is printed, and by a sheet of transparent plastic material. Typically, the sheet of paper or one of the two sheets of paper has an inner surface on which a thermally-activated adhesive is applied, for example, on the inner surface there may be a layer of adhesive, optionally shaped. The sheet provided with the thermally-activated adhesive may be a layered material already provided with an adhesive. In apparatus according to the prior art, the packaging of the plasters between two flexible sheets is carried out by advancing a continuous array of plasters along a machine direction, spaced apart from each other, and two continuous flexible sheets overlapping each other on opposite sides of the continuous array of plasters, one of which has a layer of thermally-activated adhesive, so as to form a continuous composite tape consisting of the two continuous flexible sheets and the continuous array of plasters sandwiched between the two continuous flexible sheets. The packages are closed by passing the continuous composite tape through a first and a second pair of possibly heated pressure rollers. Typically, the first pair of pressure rollers carries out two continuous longitudinal welds between the two flexible sheets, and the second pair of pressure rollers carries out welds transversal to the feed direction of the tape located between each pair of articles. The fixing between the two flexible sheets takes place by activating the thermally-activated adhesive, which occurs while the flexible sheets are compressed together along the compression lines. Subsequently, the packages are obtained from the continuous composite tape by means of suitable cuts transversal to the feed direction, typically between the transverse welds between each pair of articles. The welding between the two flexible sheets must meet precise quality requirements defined by the plaster manufacturers. The quality specifications are as follows: from the point of view of visual appearance: there must be a clear transfer of the adhesive material from one sheet to another, the welding joint must be complete and clean, without impurities and without apparent damage, the color of the packaging sheets must not change due to the welding process, and the packaging sheets must not be noticeably deformed due to the welding process;from the point of view of the sealing of the weld: the release force (peeling) must be within a precise quantified range, and during opening of the package there must be no variations in the release force outside defined thresholds between one area and the other, or between different packages;from the point of view of sealing of the weld and of the hygiene-sanitary standards: welding of the package must be such that the product is in an environment wherein any contaminants cannot access from the outside of the p