FR2831094A1 - Manufacture of plastic sleeves for large-volume containers e.g. barrels uses roll of material printed in lengthwise sections before folding, cutting and welding - Google Patents

Abstract

The procedure consists of printing a lengthwise roll of plastic film (1) with the information required for the label, on one or both sides. The film is then folded over along its Center line (1c), its edges are trimmed off to form a double lengthwise strip, and this is then welded transversely at intervals and cut along the transverse weld lines to make a series of sleeves.

Description

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METHOD FOR MANUFACTURING AND PRINTING A SLEEVE FOR VOLUMETRIC BODIES
OF GREAT CONTAINMENT
The invention relates to the technical sector of the work of plastics, especially polyethylene.

 It is well known to use sleeves to surround the periphery of any volumetric bodies. Generally, these sleeves are made of polyethylene and have a certain elasticity to be applied intimately against the outer wall of the volumetric body considered.

 In most cases, these sleeves are obtained from an extruded and blown sheath. The manufacture of these sleeves, from a sheath, has certain disadvantages, particularly in terms of printing. In fact, the printing is limited to 6 or 8 single-sided printable colors on central drum flexographic machines. In the case of double-sided printing, the latter is limited to 4 front and 4 back colors, or 5 front and 3 back colors, printed on flexographic machines with separate groups.

 Moreover, these impressions can not be obtained inside the sheath in order to be protected from external aggressions, being located between the volumetric body in question and the polyethylene. As a result, the prints can only be made outside the polyethylene.

 The tolerances of the circumference of a sheath are rarely less than plus or minus 10 mm.

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 In an attempt to overcome these disadvantages, it has therefore appeared important to be able to manufacture and print the sleeves, no longer from a sheath, but from a plastic film. Referring to Figure 1 which shows a method of manufacturing and printing a film according to the prior art, to obtain a sleeve as shown in Figure 2.

 The film (F) is printed flat. The printing zone (1) is made according to the width of the film (F), that is to say perpendicular to the extrusion direction of the film. After cutting the film in the upper part of the printing zone (1), the latter is folded in two, perpendicular to the width, in order to subject the superimposed edges to a simultaneous cutting and welding operation for example, to obtain the sleeve (Figure 2). As a result, the circumference of the sleeve obtained corresponds to the width of the film, while its height corresponds substantially to the direction of development of the printing cylinder.

 In view of these arrangements, as a result, as indicated, the dimensions of the sleeve are limited by the development of the impression cylinder and the width of the film. It is therefore not possible to obtain sleeves of sufficient circumference to be applied, as indicated, on volumetric bodies of large capacity, such as drums.

 The object of the invention is to remedy these disadvantages in a simple, safe, effective and rational manner.

 The problem that the invention proposes to solve is to be able to manufacture and print sleeves from films and no longer from sleeves,

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en ayant pour objectif de pouvoir obtenir des manchons de circonférence importante afin d'être utilisés pour des corps volumétriques de grande 1 contenance, tout en ayant par ailleurs pour objectif de pouvoir imprimer en 6 ou 8 couleurs recto-verso, tant en interne qu'en externe.

with the aim of being able to obtain large circumference sleeves for use in large volumetric bodies, while also having the objective of being able to print in 6 or 8 double-sided colors, both internally and externally. externally.

To solve such a problem, it was designed and developed a method of manufacturing and printing a volumetric body sleeve large capacity from a polyethylene film in particular, remarkable by the following steps: - performs at least one print area in the extrusion direction of the film; - fold the length of the film in half, in the direction of the length; - A section is made near and along the longitudinal edges of the folded film, so as to obtain two half-widths of film each corresponding to the desired height of the sleeve; transversely assembling half-widths so as to form a circumference; the film is cut or precut at the level of the transverse assembly of the half-widths.

According to a preferred embodiment: two symmetrical printing areas corresponding to the recto and verso and the development of the printing cylinders corresponding to the desired half-circumference are produced; the width of the film is folded in half between the two printing zones.

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 According to another characteristic, the transverse ends of the two half-widths are assembled by welding, which can be mixed in the case of an internal printing, or wire or mixed, in the case of an external printing.

 Mixed welding allows a precut between each format.

 Given the characteristics of the method on which the invention is based, the sleeve obtained has the following essential characteristics: the half-circumference of the sleeve corresponds to the development of the impression cylinder, minus the welding margin; the height of the sleeve corresponds to the half-width of the film, minus the cutting falls of the longitudinal edges; the print appears on the front and back.

 Of course, the sleeves obtained are unitary or precut coil.

- la figure 1 est une vue en perspective, à caractère schématique, montrant le procédé de réalisation du manchon à partir d'un film selon l'état antérieur de la technique ; - la figure 2 montre un manchon obtenu selon le procédé de la figure 1 ; The invention is described below in more detail with reference to the figures of the accompanying drawings, in which:

- Figure 1 is a perspective view, schematic, showing the method of producing the sleeve from a film according to the prior art; - Figure 2 shows a sleeve obtained according to the method of Figure 1;

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 FIG. 3 is a schematic perspective view showing the printing and manufacturing process of the sleeve according to the invention; - Figures 4,5 and 6 are schematic perspective views showing the main characteristic steps of the method according to the invention for obtaining a sleeve after printing and cutting the film; - Figure 7 is a schematic sectional view of the sleeve obtained; - Figure 8 is a perspective view showing the possibility of continuously obtaining a plurality of sleeves according to the features of the invention.

 FIG. 3 shows a polyethylene film (1) obtained by any known means and having, for example, the same characteristics as that illustrated in FIG. 1. According to the invention, at least one printing zone is made in the direction extruding the film (1), that is to say parallel to the edges (la) and (1b) leaving a space (1c). The width (L) represents twice the desired height of the sleeve increased edges (la) and (1b) and space (lc).

 In a preferred manner, two printing zones (R) and (V) corresponding for example to the front and back, and whose length corresponds to the development of said printing cylinders, are produced by means of rolls.

 The width of the film (1) is then folded in two, between the two printing zones (R) and (V), which are therefore superimposed opposite one another.

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 on the other (Figure 4). Then, in this folded position, a section is made close to and along the longitudinal edges of the film (1), that is to say at the level of the fold line (1 c) and the two superimposed selvedges (the ) and (lob). We thus obtain two independent half-widths corresponding to the desired half-circumference of the sleeve (Figure 5). Then simply assemble the transverse ends (Id-le) and (1f-lg) of the half-widths, so as to achieve a circumference (Figure 6).

 This assembly is performed by welding, in particular by a mixed weld in the case of an internal printing, and a wire or mixed solder, in the case of an external printing.

 Given these provisions, it follows that the half-circle (c) that has been obtained corresponds to the development of the printing cylinders (R) and (V) minus the welding margin (Id-le) and (lf -Ig) (Figure 8). The height (h) of the sleeve corresponds to the half-width of the film, minus the falls resulting from the cutting of the selvedges (1a) and (1b).

The print appears on the front and back.

 Note that the sleeves according to the characteristics of the invention are obtained in a unitary manner in the case of a wire or mixed solder, or pre-cut into coils in the case of a mixed weld.

 As a result, the laying of these sleeves can be manual, semiautomatic or automatic. As shown in Figure 8, each format is pre-cut between the welds (Id-le) and (1 f-1 g).

 The advantages are apparent from the description.

Claims (1)

 1 - A method for manufacturing and printing a sleeve for large volumetric bodies from a film (1) polyethylene in particular, characterized in that: at least one printing zone is produced in the extrusion direction of the film (1);

 the width of the film (1) is folded in half lengthwise; cutting is made close to and along the longitudinal edges of the folded film, so as to obtain two half-widths of film each corresponding to the desired height of the sleeve; transversely assembling half-widths so as to form a circumference; the film is cut or precut at the level of the transverse assembly of the half-widths.  2-Process according to claim 1, characterized in that: - two symmetrical printing areas (R) and (V) corresponding to the front and back, and the development of the printing cylinders corresponding to half desired circumference;

 the width of the film is folded in half between the two printing zones. - 3-Method according to claim 1, characterized in that assembles the transverse ends of the two half-widths, by welding. <Desc / Clms Page number 8>  - 4-A method according to claim 3, characterized in that performs a mixed weld in the case of an internal printing.

5-process according to claim 3, characterized in that one carries out a solder or mixed in the case of an external printing.  - 6-method according to any one of claims 1 to 3, characterized in that the sleeves are obtained in a unitary manner or pre-cut into coils.  7-sleeve obtained according to the method of any one of claims 1 to 6, characterized in that: - the half-circumference of the sleeve corresponds to the development of the printing cylinder, less the weld margin; the height of the sleeve corresponds to the half-width of the film, minus the cutting falls of the longitudinal edges; - the print appears on the front and back.