Heat shrink apparatus and device for packaging, and packaging line and process using said heat shrink apparatus and device
A package comprises a plastic bag delimiting a seat sealingly housing a product. The plastic bag has plastic film walls ( 4 ) and at least one sealing band connecting together opposed wall portions of the plastic film walls at a connecting zone. A tab is coupled with the connecting zone of the plastic bag. The tab includes an easy opening feature at one or more of its perimeter edges.
1. A heat shrink device for processing containers that include heat shrinkable plastic film, the containers each having a main portion in which a product is housed, a terminal portion that is not occupied by the product, and an intermediate portion connecting the main portion and the terminal portion, wherein the device comprises:
first and second shrink belts that are opposed to each other, wherein the first shrink belt has a first operative stretch facing a second operative stretch of the second shrink belt, wherein the first and second operative stretches have external surfaces defining a gap therebetween, wherein the gap is configured to receive the terminal portion of each container to be processed;
a first belt heater associated with the first shrink belt, the first belt heater configured to bring the external surface of the first operative stretch at least to a shrink temperature such that the terminal portion of each processed container passing through the gap is heat shrunk;
a sealer configured to form a heat sealing band on the terminal portion of each processed container thereby sealing each processed container; and
a pair of rollers located downstream of the first and second shrink belts with respect to a direction of movement imparted by the first and second shrink belts to the processed containers, wherein the pair of rollers define a nip therebetween for receiving the terminal portion of each processed container;
wherein the sealer includes a heated circumferential feature on an external surface of one of the pair of rollers.
2. The heat shrink device of claim 1 , further comprising a second belt heater associated with the second shrink belt, the second heat belt heater configured to bring the external surface of the second operative stretch at least to the shrink temperature such that the terminal portion of each processed container passing through said gap is heat shrunk.
3. The heat shrink device of claim 2 , further comprising first and second flattening bodies respectively associated with the first and second shrink belts, the first and second flattening bodies configured to maintain flat at least a portion of the external surfaces.
4. The heat shrink device of claim 3 , wherein the first flattening body is positioned downstream of the first belt heater with respect to the direction of movement imparted by the first and second shrink belts to the processed containers, and wherein the second flattening body is positioned downstream of the second belt heater with respect to the direction of movement.
5. The heat shrink device of claim 1 , wherein the gap is a planar gap having a constant thickness.
6. The heat shrink device of claim 1 , wherein a thickness of the gap is in a range between 0.1 mm and 2.0 mm.
7. The heat shrink device of claim 1 , wherein a thickness of the gap is in a range between 0.3 mm and 1.0 mm.
8. The heat shrink device of claim 1 , wherein a width of each of the first and second shrink belts is in a range between 20 mm and 60 mm.
9. The heat shrink device of claim 1 , wherein a width of each of the first and second shrink belts is in a range between 30 mm and 50 mm.
10. The heat shrink device of claim 1 , wherein the first belt heater is housed inside a loop defined by the first shrink belt and the first belt heater is configured to heat an inside surface of the first shrink belt.
11. The heat shrink device of claim 10 , wherein the first belt heater is configured to heat the inside surface of the first shrink belt by direct contact with the inside surface of the first operative stretch of the first shrink belt.
12. The heat shrink device of claim 1 , wherein the containers are bags or pouches made from the heat shrinkable plastic film, wherein the heat shrinkable plastic film has a free shrinking value at 120° C., measured in accordance with ASTM D2732 in oil, in a range from 2% to 80% in both longitudinal and transverse directions.
13. The heat shrink device of claim 1 , wherein the containers are bags or pouches made from the heat shrinkable plastic film, wherein the heat shrinkable plastic film has a free shrinking value at 120° C., measured in accordance with ASTM D2732 in oil, in a range from 5% to 60% in both longitudinal and transverse directions.
14. The heat shrink device of claim 1 , wherein the containers are bags or pouches made from the heat shrinkable plastic film, wherein the heat shrinkable plastic film has a free shrinking value at 120° C., measured in accordance with ASTM D2732 in oil, in a range from 10% to 40% in both longitudinal and transverse directions.
15. The heat shrink device of claim 1 , wherein the shrink temperature is in a range between 130° C. and 180° C.
16. A heat shrink device for processing containers that include heat shrinkable plastic film, the containers each having a main portion in which a product is housed, a terminal portion that is not occupied by the product, and an intermediate portion connecting the main portion and the terminal portion, wherein the device comprises:
first and second shrink belts that are opposed to each other, wherein the first shrink belt has a first operative stretch facing a second operative stretch of the second shrink belt, wherein the first and second operative stretches have external surfaces defining a gap therebetween, wherein the gap is configured to receive the terminal portion of each container to be processed
a first belt heater associated with the first shrink belt, the first belt heater configured to bring the external surface of the first operative stretch at least to a shrink temperature such that the terminal portion of each processed container passing through the gap is heat shrunk;
a sealer configured to form a heat sealing band on the terminal portion of each processed container thereby sealing each processed container; and
a pair of rollers located downstream of the first and second shrink belts with respect to a direction of movement imparted by the first and second shrink belts to the processed containers, wherein the pair of rollers define a nip therebetween for receiving the terminal portion of each processed container;
wherein the sealer includes a heated feature on an external surface of one of the first and second shrink belts.
17. The heat shrink device of claim 16 , further comprising a second belt heater associated with the second shrink belt, the second belt heater configured to bring the external surface of the second operative stretch at least to the shrink temperature such that the terminal portion of each processed container passing through said gap is heat shrunk.
18. The heat shrink device of claim 17 , further comprising first and second flattening bodies respectively associated with the first and second shrink belts, the first and second flattening bodies configured to maintain flat at least a portion of the external surfaces.
19. The heat shrink device of claim 18 , wherein the first flattening body is positioned downstream of the first belt heater with respect to the direction of movement imparted by the first and second shrink belts to the processed containers, and wherein the second flattening body is positioned downstream of the second belt heater with respect to the direction of movement.
20. The heat shrink device of claim 16 , wherein the gap is a planar gap having a constant thickness.