FR2680132A1 - Method for obtaining a protective and decorative label around the cylindrical body of an electric battery - Google Patents

Abstract

Method for causing the uniform folding of one edge of a sheet or film of a non-chlorine-containing synthetic resin, such as a film of polyethylene or polystyrene, closely following the cylindrical body, especially of an electric battery, and the overhanging edges at each end being folded over against the cross-section (transverse edge) of the said cylindrical body with heat-shrinking (thermal contraction) of the film, characterised in that at least one face of the said outer sheet (2) forming the casing or label comprises a covering (3), the quantity of which in terms of thickness or density is less in the region of the terminal edge (2b), the difference in the thickness or density of the covering (3) causing a differential in the heat-shrinkage, thus causing the fold to be shaped as a ring pressed up against the transverse face of the battery.

Description

The present invention relates to a method for obtaining, from a flat label made of heat-shrinkable synthetic material, a coating, envelope or label in form covering a cylindrical body such as a cylindrical electric battery and in which a margin or rim extends beyond the beyond each transverse section of this stack to be folded over the circular transverse faces.

And the invention also relates to the label thus produced allowing the implementation of this process.

The label therefore relates more particularly to the recovery for the establishment of a protective and decorative envelope around the cylindrical body of an electric cell.

It is known, for aesthetic reasons and for better protection as for better electrical insulation, to produce such a label made of synthetic material which comes to be folded down by its projecting margins beyond the ends of the cylindrical body while conforming on the transverse faces of the stack a crown highlighting and protecting the cylindrical edges of each end of the stack.

And it has been proposed to use for this purpose a multilayer label consisting of at least one outer face or film in
Mono-oriented PVC.

The mono-oriented PVC can thus be positioned, the molecular orientation being arranged in the circumferential direction around the cylindrical body to be covered and under these conditions the retraction of the terminal margins is done according to the desired movement by producing a disc in the shape of a crown coming apply against the circular transverse faces of the stack.

By contrast, bi-oriented synthetic films such as polyethylene and polystyrene have the disadvantage, due to their orientation along two axes, when printed or metallized, of shrinking, causing the edge to become detached (corresponding to the diameter inside the crown), which causes a negative and commercially unacceptable aesthetic effect, illustrated in particular on the
Figure 6.

This is why PVC represents an industrially convenient solution. However, the use of PVC also has drawbacks, particularly in terms of defense and environmental protection.

It is known in fact that PVC, when subjected to destruction in particular by incineration, causes chlorinated vapors and these cannot be released into the atmosphere without complex and consequently expensive smoke washing and neutralization operations.

It is therefore desirable to be able to produce a label, in particular on a stack, causing an aesthetic and effective retraction, the edge of which remains pressed against the transverse face of the stack, using a material in particular a synthetic film other than PVC.

And the invention responds to this concern and makes it possible, in a new, elegant and unexpected way, to use a non-chlorinated shrinkable plastic film such as polystyrene or polyethylene or any other polymer for the production of protective labels and decoration around the cylindrical body of electric batteries.

To this end, the invention relates firstly to a method for causing regular folding of a marginal edge coming from a sheet or film of a non-chlorinated synthetic resin even possibly bi-oriented, such as a polyethylene film or of polystyrene, said sheet initially conforming by winding around the cylindrical body a sleeve marrying said cylindrical body in particular of an electric battery and the marginal edges projecting at each end being folded against the transverse edge of said cylindrical body, each marginal edge or margin folded down and folded thus conforming a crown, without detachment or upward raising of the circular edge corresponding to the inside diameter of said crown, and the method is characterized in that at least one face of said outer sheet constituting the envelope or label comprises a coating whose quantity, thickness or density, is lower at the edge t erminal of the sheet overflowing with respect to the zone situated against and near the cylindrical wall, the sheet placed by gluing on the cylindrical body to marry the wall thereof being subjected to thermal shrinkage to cause the folding of said margin in overflow, and the difference in the quantity in thickness or in density of the coating between the part close to the body of the pile and the terminal part causing a differential in the retraction, this retraction being greater in the free part of any coating and causing thus the conformation of the fold according to a crown pressed against the transverse face of the stack.

The invention secondly relates to a label allowing the implementation of the above process and characterized in that it comprises on a silicone substrate at least one and preferably two sheets of non-chlorinated synthetic material even possibly bi-oriented, such as polyethylene or polystyrene, the format of the label making it possible to wrap the wall of the cylindrical body of the stack, leaving a margin at each end to overhang the part folded against the transverse face of the stack, and the outer sheet has a coating of uneven thickness or density in said margin projecting from the transverse edge of the stack, the thickness or density of the coating being less at the terminal edge of the sheet.

According to one embodiment, said sheet comprises in the protruding margin beyond each end of the cylindrical body of the stack a coating having a gradient of thickness or density decreasing from the zone of the sheet situated against the cylindrical wall to the edge leaf free terminal.

According to a more particular embodiment, the coating is interrupted near the terminal edge projecting beyond the transverse edge of the stack, leaving a fringe free of any coating.

And more specifically, said fringe free from any coating has a width of between 0.5 and 2 millimeters and it occupies at most half the width of said margin.

According to one embodiment, the coating applied to the outer sheet consists of a colored print.

According to a variant, the coating consists of a metallization layer.

And more specifically, the coating is arranged on the inside of the sheet.

Other characteristics and advantages of the invention will emerge from the description which follows and which is given in relation to two embodiments presented by way of nonlimiting examples with reference to the appended drawings.

Figure 1A shows a schematic sectional view of a label according to a first embodiment placed on the cylindrical body of a stack with a gradient in the printing, Figure 1B representing the perspective view of the label in place before retraction.

Figure 2A shows the label in cross-section of Figure 1A after shrinking and Figure 2B shows a perspective view of the label after shrinking.

Figure 3A shows a schematic and sectional view of a label according to a variant of the invention placed on the cylindrical body of a stack, Figure 3B representing this label in perspective on the body of the stack, before retraction .

Figure 4A shows a sectional view of the label of Figure 3A after shrinking, while Figure 4B shows this label shrunk in perspective.

Figures 5A, 5B and 5c show other more complex embodiments of a multi-layer label applying the principle of the invention.

Figure 6 shows the defect presented by a label in bi-oriented material and printed or metallized and not using the process or the device of the invention.

According to FIGS. 1A, 1B, 2A, 2B, it can be seen that a label is placed against the cylindrical casing 1 of a stack, which is here represented in a simplified form for the purposes of the intelligence of the invention. ; complex and effectively used label shapes being shown in Figures 5A and 5B; Figures 1A to 4B show a stripped form of label with a single layer to explain more directly the establishment of the label according to the invention.

According to Figures 1A to 2B, a label has been produced consisting of an outer sheet 2 here made of polystyrene or polyethylene, that is to say a film of a bi-oriented polymer.

This sheet 2 has on its inner face and on the underside a printing layer 3 and it is applied to the cylindrical wall of the stack 1 by a coating layer 4 of an adhesive.

As can be seen in FIG. 1A, the printing layer 3a in the area of the label 2a which projects beyond the body of the stack, that is to say on the projecting margin, has a decreasing thickness from the level of the edge 1a of the stack up to the terminal edge 2b of the margin 2a of the sheet 2.

We see in Figure 2A, the positioning of the sheet 2 after thermal shrinkage.

The shape of the sheet in Figure 2A should be compared to the shape which has been shown in
Figure 6 and which illustrates the positioning in section of the sheet 2 outside the scope of the present invention.

We see that in the establishment of a bi-oriented sheet printed or metallized outside the invention, according to the
Figure 6, the retraction leaves a rise in the terminal edge 2a of the sheet which peels off relative to the transverse wall la of the stack, offering an unsightly and commercially unacceptable appearance, when the sheet 2 has an underlay printing 3 which is the general case to ensure the decoration and the beautiful appearance of the product.

In the context of the present invention, the gradient in the thickness of the marginal part 3a of the print 3 introduces a correction element which makes it possible to obtain the final conformation of the label in its marginal part in accordance with FIG. 2A .

The gradient in the thickness of the coating layer consisting of a print can be replaced in the case of raster printing by a density gradient, the thickness of the printed coating then remains constant but the surface printed on the film 2 in each discrete area of the frame is more reduced, thereby achieving a gradient in the amount of printing affixed and transferred to the marginal part 2a of the film.

It is understood that the printing 3a introduces a correcting element, possibly stiffening, of the marginal part 2a; and this stiffening being uneven leaves a possibility of greater retraction towards the terminal part 2b.

Under these conditions, the part 2b which is freer and therefore more strongly retracted on itself comes to tighten by pressing against the transverse wall 1a of the body of the stack, avoiding any raising.

A simple, elegant and effective means is thus obtained to control and command the correct positioning of the folded margin 2a of the label against the transverse wall of the stack.

Furthermore, it will be observed that the central part 2b being more retracted with respect to the zone of the label situated against the wall of the stack, the slightest pigmentation or the less dense colored impression in this terminal part is compensated, so that we find on part 2a (of Figure 2A) the uniform coloring as it appears on the body of the label.

Figures 3A to 4B show a variant in which the thickness gradient in the printing or coating layer 3 instead of decreasing linearly from the transverse wall la of the stack towards the terminal edge 2b of the sheet 2, s' stops near this edge 2b leaving a shoulder or fringe 2c free of any coating.

We see that we obtain, after thermal shrinkage according to Figure 4A, a configuration substantially similar to that of Figure 2A, the terminal edge 2b being retracted towards the center more significantly since due to the free fringe 2c, without coating, this end portion 2b is less braked in its retraction and thus ensures a tightening of the edge 2b in a circle corresponding to the inner circle of the crown shaped by the margin 2a pressed on the corresponding transverse edge of the stack.

And as indicated previously, FIGS. 5A, 5B and 5C show more complex forms of implementation of the invention in which the outer sheet 2, for example made of transparent polyethylene or polystyrene, is associated with sublayers.

We find in particular the printing sublayer 3 which may consist of pigmentation or colored ink on the entire surface or in zones.

Printing 3 by zones will make it possible in particular, in the case of FIG. 5B, to reveal by transparency the metallization layer 5 giving a luminous and aesthetic appearance to the entire body of the stack.

A layer 2 ′ of a synthetic film identical to film 2 can be opaque in the case of FIG. 5A or possibly transparent (film 2 ′) in the case of Figure 5B where it is associated with an intermediate metallization layer 5, provided with a decreasing thickness gradient in the marginal part projecting above the plane la constituted by the transverse edge of the stack.

The assembly is transferred to the body of the stack I by the layer of adhesive 4 and an intermediate layer of adhesive 4 'makes it possible to interface the assembly of the assembly.

In the case of FIGS. 5A and 5B it can be seen that the printing layer 3, which thus constitutes a coating on the underside of the outer sheet 2, has a thickness gradient in the projecting part beyond the plane corresponding to it. transverse section of the stack 1 and as explained above, this gradation in the printing makes it possible to cause the greater retraction of the terminal edge 2a of the outer sheet 2, consequently ensuring its correct positioning against the plane la of the transverse section of the stack without the lifting effect illustrated in Figure 6.

In the case of FIG. 5C, the printing layer 3 is transferred to the metallization layer 5.

It is understood that the invention is not limited to the embodiments which have been described and it may include various variants or embodiments using for example a third intermediate sheet between the lower sheet 2 'and the outer sheet 2 .

The gradient printing sublayer can be produced by screening of colored pigments added on the underside of the outer sheet 2 or by any other means making it possible to measure the quantity of colored coatings (ink, wax, pigments) put in place. and which will allow, by its thickness variation, to obtain the maximum retraction of the outer sheet on its internal edge after folding under the effect of thermal retraction.

Claims (12)

1 - Method for causing regular folding of a marginal edge coming from a sheet or film of a non-chlorinated synthetic resin and this despite a biorientation of the film, such as a polyethylene or polystyrene film, said sheet conforming to the departure by winding around the cylindrical body a sleeve marrying said cylindrical body in particular of an electric battery and the marginal edges, projecting at each end beyond the transverse edge of the stack, being folded against said transverse edge of said cylindrical body with thermal retraction of the film, each marginal edge or margin folded and folded thus conforming a crown, without detachment or upward raising of the circular edge corresponding to the inside diameter of said crown, and the method is characterized in that at least one face of said outer sheet (2) constituting the envelope or label comprises a decorative coating (3) consisting of a co printing or metallization hutch whose quantity in thickness or density is lower at the terminal edge (2b) and in overflow of the sheet with respect to the zone situated against and near the cylindrical wall (1), the sheet (2) placed by gluing on the cylindrical body to match the wall being subjected to thermal shrinkage to cause the folding of said margin (2a) in overflow, and the difference in the thickness or density of the coating (3 ) between the part near the body of the stack and the terminal part (2b) causing a differential in the retraction, this retraction being greater in the part which is less rich in coating or free of any coating and thus causing the configuration of the fold according to a crown pressed against the transverse face of the stack. 2 - Label allowing the implementation of the method according to claim 1 above and characterized in that it comprises on a silicone substrate at least one and preferably two sheets of synthetic material even bioriented and non-chlorinated (2, 2 ' ), such as polyethylene or polystyrene, the format of the label making it possible to wrap the wall of the cylindrical body of the stack by allowing a margin (2a) to protrude at each end intended to conform the part folded against the face (the ) transverse of the stack (1), and at least the outer sheet (2) comprises a coating (3) of quantity in thickness or uneven density in said margin in overflow relative to the transverse edge of the stack, the quantity in thickness or the density of the coating being lower at the end edge (2b) of the sheet. 3 - Label according to claim 2, characterized in that said outer sheet (2) comprises in the margin (2a) projecting beyond each end (la) of the cylindrical body (1) of the stack a coating (3) having a decreasing thickness or density gradient from the zone of the sheet situated against the cylindrical wall to the free end edge (2b) of the sheet. 4 - Label according to claim 2, and characterized in that the coating (3) is interrupted near the terminal edge (2b) projecting beyond the transverse edge of the stack leaving a fringe (2c) free of any coating . 5 - Label according to claim 4, and characterized in that said fringe (2c) free of any coating has a width between 0.5 and 2 millimeters and it occupies at most half the width of said margin (2b). 6 - Label according to one of claims 2 to 5, and characterized in that the coating applied to the outer sheet consists of a colored print. 7 - Label according to one of claims 2 to 5, and characterized in that the coating consists of a metallization layer. 8 - Label according to one of claims 2 to 7, characterized in that the coating is arranged on the inner face of the outer sheet (2). 9 - Label according to one of claims 2 to 7, characterized in that the coating is arranged on the outer face of the inner sheet 2 '. 10 - Label according to claim 2, characterized in that the decreasing amount of the coating near said terminal edge 2b is obtained by a variation in the value of the frame. 11 - Cylindrical stack coated with a label according to one of claims 2 to 10 above, and characterized in that its covering label, comprising on the part projecting beyond the transverse edges of the stack a thick coating or decreasing density towards its terminal edge, is folded by this edge against the edge of the stack, the edge being pressed against said edge. 12 - Battery according to claim 11, and characterized in that the printed label comprises, after retraction of the edges, a uniform coloring even on the retracted edges, the pigmentation decreasing on the said edges of the label before retraction finding an identical density to that of the body of the label due to the retraction of the film resulting in redensifying the pigmentation on the tightened area, joining the uniform coloring of the label.