Sleeve heat-shrinking method and machine

Abstract

Heat-shrinking a sleeve (2) around a body (3) such as a bottle or jar involves transferring energy to a tube (14) such that the tube (14) re-emits radiation with wavelengths in the range of 300nm to 5000nm from its inner face, and then moving the tube (14) around a heat-shrinkable sleeve (2) fitted on a respective bottle (3) or inserting the sleeve (2) fitted on the bottle (3) inside the tube (14).

Description

[0001] SLEEVE HEAT-SHRINKING METHOD AND MACHINE

[0002] Cross-Reference To Related Applications

[0003] This patent application claims priority from Italian patent application no . 102024000003151 filed on February 14 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0004] Technical Field

[0005] This invention relates to a shrink sleeve shrinking method for decorating bottles , j ars and vials .

[0006] The shrinking of shrink sleeves around solid bodies is particularly popular in the packaging and sublimation printing industries and involves placing a sleeve made of heat-shrinkable material around a solid body and trans ferring heat to the sleeve so that it shrinks and adheres to the outer surface of the solid body .

[0007] State of the Art

[0008] The shrinking of a sleeve is generally performed in a tunnel in which heat is trans ferred to the sleeve by supplying steam or hot air or using radiating panels . The use of steam is not suitable for s leeves made of water-based and, therefore , steam-soluble materials . Tunnels with radiating panels or hot air circulation or a combination of radiating panels and hot air circulation do not guarantee complete and uni form shrinking, especially in sleeves made from a multilayer film .

[0009] Subject of the Invention

[0010] The purpose of this invention is to provide a shrinking method that is free or, at least , mitigates the drawbacks of the prior art .

[0011] In accordance with this invention, a heat-shrinking method for shrinking a sleeve made of heat-shrinkable material around a solid body, in particular a bottle , j ar or vial , is provided, the method comprising :

[0012] - trans ferring energy to a tube such that the tube reemits radiation with wavelengths in the range of 300 to 5 , 000 nm from its inner face ; and arranging the tube around a sleeve fitted on a respective solid body in rapid sequence or placing the sleeve fitted on the solid body inside the tube for a speci fied time .

[0013] The tube allows the sleeve to be completely wrapped around it , containing the heat ins ide the tube and ensuring uni form shrinking of the sleeve .

[0014] In particular, the energy trans fer involves heating the tube to a temperature above 280 ° C in order to allow the emission of waves within the speci fied wavelength range and achieve fast and orderly shrinking . At the same time , it is preferable to keep the tube temperature below 380 ° C to preserve the material from which the tube is made .

[0015] In particular, energy is generated by radiating panels arranged around the tube and configured to emit radiation in the infrared range in a manner that is simple to construct and manage .

[0016] From a structural point of view, the radiating panels are conveniently distributed along multiple rings extending around a given axis .

[0017] In particular, each ring is temperature-controlled independently of the other rings in order to equalise the temperature of the tube along the given axis, should it be necessary during use. In fact, the tube temperature may differ along the axis due to multiple factors, such as different exposure to cooling sources.

[0018] In particular, the tube is made of a material that has light absorption and reflection characteristics close to those of a black body, i.e. a low reflectance coefficient and a high emissivity coefficient, while at the same time guaranteeing resistance over time to continuous variations in thermal cycles, without breaking and without changing its dimensions significantly as the temperature changes. In addition, the material must ensure even heating during the process. Examples of materials with the required characteristics include stainless steels 304, 316, or 310 with a dark grey or black sandblasting or painting treatment, alloy steels such as H13 steel, or chromium-molybdenum steels (e.g. 9Cr-lMo.) , or Inconel or Black Nickel. These materials make it possible, with appropriate treatments, to simulate or approximate the light absorption and reflection characteristics of a black body (i.e. a low reflectance coefficient and high emissivity coefficient) and at the same time ensure that they can withstand continuous variations in thermal cycles over time, without breaking or changing their dimensions significantly as the temperature changes. In addition, the material must ensure even heating during the process .

[0019] In particular, the tube has an inner face with a surface roughness Ra between 0.8 and 30 microns, preferably between 1 and 5 microns .

[0020] In this way, radiation inside the muf fle propagates along multiple directions not necessarily perpendicular to the inner face of the tube to the benefit of the uni form heating of the muf fle .

[0021] In particular, the tube has an outer face with a surface roughness Ra between 0 . 8 and 30 microns , preferably between 1 and 5 microns so as to optimise radiation absorption .

[0022] In accordance with one embodiment of this invention, the outer surface and the inner surface are of a very dark colour, such that they have a reflectance coef ficient of less than 20% , in particular les s than 5% , such as a very dark and opaque grey, or a black opaque colour .

[0023] Thus , the inside of the muf fle , behaving like a black body, re-emits radiation at all wavelengths in the infrared spectrum, i . e . between 300 nanometres and 5000 nm . This is particularly relevant since , being predominantly transparent at wavelengths in the visible spectrum, the film would not be able to absorb the heat required for shrinking in the presence of waves with lambda near 300 nm . While it absorbs longer wavelength radiation very well .

[0024] Speci fically, the sleeve is made from a sheet of multilayer material comprising an outer layer of heat- shrinkable PETg and an inner layer comprising mostly polyvinyl alcohol . Sublimation pigments are applied to the sheet along the inner layer .

[0025] In particular, the solid body has opposite first and second ends , the sleeve comprising a first and second flap (which extend beyond the first and second ends of the solid body, respectively) to close the ends of the solid body .

[0026] Speci fically, the method involves placing an elongated body at the first flap, and at a speci fied distance from the first end of the solid body; heat shrinking the first flap around the elongated body; and extracting the elongated body from the heat-shrunk flap so that the first flap can be neatly welded at the first end of the solid body .

[0027] Another purpose of this invention is to provide a heatshrinking machine , which is free from the drawbacks of the prior art .

[0028] In accordance with this invention, a heat-shrinking machine for heat shrinking a sleeve made of heat-shrinkable material around a solid body is provided, the machine comprising :

[0029] - at least one heat-shrinking apparatus , which includes a tube configured to trans fer energy to the sleeve ; and a heating device with radiating panels to trans fer energy to the tube in the form of radiation in the infrared range such that the tube re-emits radiation with wavelengths in the range of 300 to 5 , 000 nm from its inner face ; and

[0030] - a handling device configured to arrange the tube around the solid body and a respective sleeve fitted on the solid body or to insert the solid body and the respective sleeve fitted on the solid body inside the tube .

[0031] This keeps the heat inside the tube and heats the sleeve evenly .

[0032] In particular, the heat-shrinking machine includes a support device configured to support the solid body and its sleeve along a given axis in order to facilitate their movement .

[0033] In particular, the heat-shrinking machine comprises a conveyor configured to advance multiple solid bodies and their respective sleeves fitted around the respective solid bodies along an advancement path, along which at least one heat-shrinking apparatus is arranged .

[0034] Brief Description of the Drawings

[0035] Further features and advantages of this invention will be apparent from the following description of a non-limiting embodiment thereof , with reference to the Figures of the accompanying drawings , wherein :

[0036] - Figure 1 is an elevated view, with parts removed for clarity, of a heat-shrinking machine produced in accordance with this invention;

[0037] - Figures 2 and 3 are side elevation cross-section views , with parts removed for clarity, of the heat-shrinking machine in Figure 1 in two successive operating steps ;

[0038] Figure 4 is a plan view with parts removed for clarity, of a heat-shrinking machine produced according to a further embodiment of this invention; and

[0039] - Figures 5 and 6 are two cross-section views , with parts removed for clarity, of the machine in Figure 4 in two di f ferent operating steps .

[0040] Preferred Embodiment of the Invention

[0041] With reference to Figure 1 , the reference number 1 denotes , as a whole , a heat-shrinking machine for heatshrinking a sleeve 2 fitted around a solid body 3 ( Figure 2 ) , in this illustrated case a bottle .

[0042] The sleeve 2 is made from a water-soluble multilayer film printed with sublimation inks along its inner face . In particular, the sleeve 2 comprises an outer layer made of heat-shrinkable PTEg, an inner layer comprising mainly polyvinyl alcohol s . Sublimation pigments are applied to the sheet along the inner layer .

[0043] With reference to Figure 2 , the solid body 3 , in the example illustrated, is a hollow body, in this example a bottle , and has two opposite ends 4 and 5 .

[0044] The sleeve 2 has a longer length than the solid body 3 and, in this case , is fitted onto the solid body 3 so that two flaps 6 and 7 protrude from the ends 4 and 5 of the hollow body 3 , respectively .

[0045] The machine 1 comprises a conveyor 8 , which extends along a given path Pl to successively advance the solid bodies 3 with their sleeves 2 at a heat-shrinking station 9 .

[0046] The conveyor 8 comprises multiple support devices 10 , each of which is configured to support a respective solid body 3 and the respective sleeve 2 along a given, essentially vertical axis . The conveyor 8 is advanced in steps and alternates between steps in which it is stationary and when shrinking is carried out and steps when it moves forward . The support device 10 comprises a tool 11 configured to hold the end 4 of the solid body and a plate 12 , on which the sleeve 2 rests .

[0047] The machine 1 comprises a heat-shrinking apparatus 13 , which is arranged above the conveyor 8 in the heat-shrinking station 9 , extends along an essentially vertical axis Al and comprises a tube 14 , which extends around the axis Al and is configured to trans fer energy to the sleeve 2 ; a heating device 15 for trans ferring energy to the tube 14 in the form of radiation in the infrared range such that the tube 14 reemits radiation with wavelengths in the range of 300 to 5 , 000 nm from its inner face ; and a handling device 16 for selectively arranging the tube 14 around the solid body 3 and a respective sleeve 2 fitted on the solid body 3 .

[0048] The tube 14 is movable along a vertical traj ectory parallel to the axis Al between a raised position, in which the tube 14 is arranged inside the heating device 15 ( Figure

[0049] 2 ) , and a lowered position, in which the tube 14 is arranged around a sleeve 2 and a respective solid body 3 arranged in the heat-shrinking station and aligned along the axis Al .

[0050] The drive device 16 comprises guides 17 to guide the tube 14 between the raised position ( only one guide 17 is shown in Figures 1 and 2 ) and the lowered position ( Figure

[0051] 3 ) .

[0052] The heating device 15 comprises multiple radiating panels 18 integral with a frame not illustrated in the accompanying figures and arranged to form a cylindrical housing configured to closely contain the tube 14 when the tube 14 is arranged in the raised position . The radiating panels 18 are grouped in rings 19 distributed along the axis Al .

[0053] The tube 14 has multiple circumferential notches (not illustrated in the accompanying figures ) distributed along the longitudinal extension of the tube 14 and configured to be arranged at the separation between two successive rings 19 of radiating panels 18 when the tube 14 is arranged in the raised position ( Figures 1 and 2 ) . In particular, the tube 14 is made of steel or steel alloys or nickel or nickel alloys such as Inconel . The inner and outer faces of the tube 14 have a surface roughness of between 0 . 8 and 30 microns and, in particular, between 1 and 5 microns .

[0054] The tube 14 is dull dark grey or black so that the tube ' s reflectance is less than 20% and in particular less than 5% .

[0055] The heat-shrinking apparatus 13 comprises an inserter device 20 for arranging an elongated body 21 at the first flap 6 , and at a given distance from the first end 4 of the solid body 3 before heat shrinking the first flap 6 around the elongate body 21 ; and extracting the elongated body 21 from the heat-shrunk flap .

[0056] In Figure 1 , the elongated body 21 is in a raised position, while in Figures 2 and 3 it is in a lowered position .

[0057] The inserter device 20 comprises stems 22 that extend axially within the tube 14 and two heat-resistant sheaths 23 within which the stems 22 move .

[0058] The conveyor 8 includes an actuator 24 to advance the solid bodies 3 connected to respective sleeves 2 along the path Pl . The handling device 16 includes an actuator 25 to lower and raise the tube 14 in the heat-shrinking station 9 , and the inserter device 20 includes an actuator 26 to lower and raise the elongated body 21 .

[0059] The machine 1 comprises a control unit 27 , which is connected to the actuators 24 , 25 , 26 and to the radiating panels 18 to control and synchronise the movements of the conveyor 8 , the tube 14 and the elongated body 21 and the energy transmitted to the radiating panels 18 according to the working cycle and the temperatures required to suitably heat the tube 14 .

[0060] In use , the conveyor 8 advances the support device 10 in steps in such a way that a solid body 3 and the respective sleeve 2 are essentially aligned with the axis Al in the heat-shrinking station 9 as shown in Figure 1 . Following this , the elongated body 21 is lowered and placed inside the flap 6 and at a given distance from the end 4 of the solid body 3 as shown in Figure 2 . Meanwhile , the radiating panels 18 heat the tube 14 .

[0061] Following this , the tube 14 is lowered and arranged around the solid body 3 and sleeve 2 so that the sleeve 2 is shrunk around the solid body 3 and the elongated body 21 , which is then extracted . The function of the elongated body 21 is to facilitate an orderly weld at the end 4 of the solid body 3 . In other words , part of the flap 6 adheres to the elongated body 21 while the part of the flap 6 next to the end 4 forms a weld .

[0062] Once the elongated body 21 has been shrunk and extracted, the solid body and the sleeve 3 define an assembly 28 provided with an appendage 29 suitable for undergoing a sublimation process for decorating the solid body 3 .

[0063] The applicant carried out experimental tests of the shrinking method using the following parameters .

[0064] The tube 14 made of 1 cm thick H13 steel is sandblasted to achieve a surface roughness Ra along the inner and outer faces of approximately 3 microns and a reflectance of less than 10% .

[0065] The sheet to produce the sleeve 2 comprises an outer layer made of heat-shrinkable PTEg and an inner layer mainly comprising polyvinyl alcohols . A sublimation pigment was applied to the sheet .

[0066] The tube 14 was heated to temperatures between 450 ° C and 600 ° C to achieve temperatures along its inner face in the range of 280 ° C to 360 ° C .

[0067] The dwell time of the solid body 3 and the respective sleeve 2 was varied between 0 . 5 and 5 s depending on the si ze of the solid bodies 3 and their respective sleeves 2 , which include small perfume bottles , 0 . 75 1 bottles generally used to hold wine and spirits , and candle j ars .

[0068] The results obtained from the above tests were largely positive because uni form shrinking could be achieved in a relatively short time even in solid bodies with complex shapes .

[0069] Figure 4 shows a heat-shrinking machine 30 , which comprises a support 31 and a conveyor 32 mounted to rotate around the axis A2 relative to the support 31 and configured to advance the solid bodies associated with the respective sleeves 2 along a path P2 .

[0070] In the case illustrated, the machine 30 comprises six heat-shrinking apparatuses 33 , which are associated with the moving part of the conveyor and rotate around the axis A2 .

[0071] Referring to Figure 5 , the conveyor 32 comprises a drum 34 that rotates about the axis 2 , and multiple support devices 35 , in this illustrated example six, each of which is arranged under a respective heat-shrinking apparatus 33 , is aligned with the respective heat-shrinking apparatus 33 along a respective axis Al , and is configured to support a solid body 3 and a respective sleeve 2 fitted on the solid body 3 .

[0072] The machine 30 includes multiple handling devices 36 , each of which is associated with a respective support device 35 and is configured to raise and lower the respective support device 35 to insert a solid body 3 and the associated sleeve 2 into the heat-shrinking apparatus 33 and, once shrinking is performed, extract the assembly 28 . The handling device 36 comprises a slide 37 moving along a guide 38 and an actuator 39 .

[0073] The heat-shrinking apparatus 33 has the same technical characteristics as described in relation to the previous embodiment with the sole exception that the tube 14 and the heating device are fixed with respect to each other and that the inserter device 20 performs a slightly di f ferent cycle of movements than those described in relation to the previous embodiment .

[0074] The conveyor 32 is driven by an actuator 40 to rotate the conveyor 32 and the respective heat- shrinking apparatuses 33 around the axis A2 .

[0075] The machine 1 comprises a control unit 41 , which is connected to the actuators 40 , 39 , 26 and to the radiating panels 18 to control and synchronise the movements of the conveyor 32 , the support device 35 and the elongated body 21 and the energy transmitted to the radiating panels 18 according to the working cycle and the temperatures required to suitably heat the tube 14 . In use , the conveyor 32 can be advanced continuously around the axis A2 j ust as shrinking can be performed while advancing the conveyor 32 .

[0076] Finally, it is clear that , this invention comprises additional variants of the embodiments described and included within the scope of protection of the attached claims .

Claims

CLAIMS1. A heat-shrinking method for shrinking a sleeve (2) of heat-shrinkable material around a solid body (3) , particularly a vial or bottle or jar; the method comprising:- transferring energy to a tube (14) such that the tube (14) re-emits radiation with wavelengths in the range of 300 to 5,000 nm from its inner face; and- arranging the tube (14) around a sleeve (2) fitted on a respective solid body (3) in rapid sequence or placing the sleeve (2) fitted on the solid body (3) inside the tube (14) for a specified time.

2. The method as claimed in Claim 1, wherein the energy transfer comprises heating the tube (14) to a temperature between 280°C and 380°C.

3. The method as claimed in Claim 1 or 2, wherein the energy transfer is accomplished by radiating panels (18) arranged around the tube (14) and configured to emit a radiation in the infrared range.

4. The method as claimed in Claim 3, wherein the radiating panels (18) are distributed along a plurality of rings (19) extending around a determined axis (Al) .

5. The method as claimed in Claim 4, wherein the tube (14) has a plurality of circumferential notches distributed in an axial direction and arranged at the separation between two successive rings (19) of radiant panels (18) when the tube (14) is disposed between the radiant panels.

6. The method as claimed in claim 4 or 5 and comprising controlling in temperature each ring (19) independently with respect to the other rings (19) and the radiant panels (18)facing said ring.

7. The method as claimed in any one of the preceding Claims, wherein the tube (14) is made of a material selected from steel, nickel, Inconel, steel alloys, and nickel alloys.

8. The method as claimed in any one of the preceding Claims, wherein the tube (14) has an inner face having a surface roughness Ra between 0.8 and 30 microns, particularly between 1 and 5 microns.

9. The method as claimed in any one of the preceding Claims, wherein the tube (14) has an outer face having a surface roughness Ra between 0.8 and 30 microns, particularly between 1 and 5 microns.

10. The method as claimed in any one of the preceding Claims wherein the colour of the inner face of the tube (14) has a reflectance of less than 20%.

11. The method as claimed in any one of the preceding Claims, wherein the sleeve (2) is made from a sheet of multilayer material comprising an outer layer of PETg an inner layer based on polyvinyl alcohol.

12. The method as claimed in any one of the preceding Claims, wherein in solid body has a first and second opposite ends (4, 5) , the sleeve (2) comprising a first and second flap (6, 7) extending beyond the first and second ends (4, 5) of the solid body (3) , respectively.

13. The method as claimed in Claim 12 and comprising arranging an elongated body (21) at the first flap (6) , and at a distance determined from the first end of the solid body; heat shrinking the first flap around the elongate body; and extracting the elongate body from the heat-shrunk flap.

14. A heat-shrinking machine for shrinking a sleeve made of heat shrinkable material around a solid body, the equipment (1; 30) comprising:- at least one heat-shrinking apparatus (13; 33) , which includes a tube (14) configured to transfer energy to the sleeve (2) ; and a heating device (15) with radiant panels to transfer energy to the tube (14) in the form of radiation in the infrared range such that the tube (14) re-emits from its inner face radiation with wavelengths in the range of 300 to 5,000 nm; and- a handling device (16; 36) configured to arrange the tube (14) around the solid body (3) and a respective sleeve(2) fitted on the solid body (3) or insert the solid body(3) and the respective sleeve (2) shod on the solid body (3) inside the tube (14) .

15. The heat-shrinking machine as claimed in Claim 14, wherein the solid body (3) has a first and a second end (4, 5) opposite each other, the sleeve (2) comprising a first and a second flap (6, 7) extending beyond the first and second ends (4, 5) of the solid body (3) , respectively; the shrinking apparatus (13; 33) comprising an inserter device (20) to selectively place an elongated element (21) within the first flap (6) and at a determined distance from the first end ( 4 ) .

16. The heat-shrinking machine as claimed in Claim 14 or 15 and comprising a support device (10; 35) configured to support the solid body (3) and associated sleeve (2) along a determined axis.

17. The heat-shrinking machine as claimed in any one ofClaims 14 to 16 and comprising a conveyor (8; 32) configured to advance a plurality of solid bodies (3) and their respective sleeves (2) socked around the respective solid bodies (2) along an advancement path (Pl; P2) , along which at least one heat shrinking apparatus (13; 33) is arranged.

18. The heat-shrinking machine as claimed in Claim 17 and comprising a control unit (27; 41) configured to control the heating device (15) , the handling device (16; 36) , and the conveyor (8; 32) .

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