Method for sealingly attaching a peripheral attachment member onto a filled-sealed pouch
The invention relates to a method for sealing a peripheral attachment member onto a sealed pouch that has been previously filled with a product. The invention also relates to a pouch that includes a peripheral attachment member sealingly attached to at least one of its faces. The method includes a step of providing a multi-layer pouch that is configured so as to provide an inner sealant adapted to form a closed enclosure along sealing lines and an outer sealant that forms at least one external face of the pouch wherein the outer sealant has a melting point that is lower than the melting point of the inner sealant.
1. A method for sealingly connecting a peripheral member onto a closed pouch wherein the pouch has been previously filled with product and sealed to form a sealed enclosure retaining the product therein, the method comprising:
providing a flexible, multilayer pouch comprising an inner sealant sealed to form a closed enclosure with the product contained therein, and an outer sealant forming at least one external face of the pouch, wherein the outer sealant is adjacent to the inner sealant at a location where the peripheral member is to be connected and has a melting point that is lower than that of the inner sealant;
providing the peripheral attachment member comprising at least one sealant that has a melting point or seal initiation temperature that is lower than the melting point or seal initiation temperature of the inner sealant of the pouch and that has sealing characteristics that are compatible with the outer sealant layer of the pouch,
positioning the sealant of the peripheral attachment member in contact with the outer sealant at at least one sealing interface area,
applying sealing energy at the sealing interface area to provide an intimate seal between the peripheral attachment member and the outer sealant of the pouch, and
releasing or removing the sealing energy before the melting point or the seal initiation temperature of the inner sealant is achieved.
2. The method according to claim 1 , which further comprises flattening the pouch at the sealing interface area against the peripheral attachment member with two parts of the inner sealant of the pouch pressed to each other before applying the sealing energy.
3. The method according to claim 2 , wherein the flattening of the pouch is achieved by providing a sealing die that maintains stationary contact at the sealing interface area and pressure between the peripheral attachment member and the two parts of the flattened pouch during application of the sealing energy.
4. The method according to claim 3 , wherein the sealing energy to be applied is thermal energy transferred from the die to the sealing interface area.
5. The method according to claim 4 , wherein the intimate seal is a heat seal that is obtained by transferring heat from the part of the die that contacts the rear of the pouch through the inner and outer sealants of the pouch to the sealant of the peripheral attachment member.
6. The method according to claim 4 , wherein the heat seal is obtained within a temperature range that is at least 2° C. lower than the melting temperature or seal initiation temperature of the inner sealant of the pouch.
7. The method according to claim 4 , wherein the heat seal is obtained within a temperature range that is at least 5° C. lower than the melting temperature or seal initiation temperature of the inner sealant of the pouch.
8. The method according to claim 1 , wherein the sealant of the peripheral attachment member is made of a material that is compatible with the outer sealant and has a melting point temperature that is sufficiently close to the melting point of the outer sealant to initiate sealing before sealing with the inner sealant is initiated.
9. The method according to claim 8 , wherein the fitment and its sealant are made of a single integral part.
10. The method according to claim 8 , wherein the fitment and its sealant are distinct components.
11. The method according to claim 10 , wherein the sealant is made of metallocene catalyzed alpha-olefin polymer or copolymer.
12. The method according to claim 1 , wherein the peripheral attachment member is a fitment.
13. The method according to claim 12 , wherein the sealant is a film that is sealed to the fitment before attaching the fitment to the outer sealant of the pouch.
14. The method according to claim 1 , wherein the outer sealant of the pouch is made of a polyolefin, a polyolefin copolymer or a blend thereof.
15. The method according to claim 14 , wherein the outer sealant is a linear low density polyethylene, an ultra low density polyethylene, or a metallocene catalyzed alpha-olefin polymer or copolymer.
16. The method according to claim 14 , wherein the inner sealant is a polyolefin, polyolefin copolymer, or polyolefin blend.
17. The method according to claim 16 , wherein the inner sealant is a linear medium density polyethylene or a high density polyethylene.
18. The method according to claim 1 , wherein at least the outer sealant of the pouch or the sealant of the peripheral member is a light absorbent layer that provides heat at specific wavelengths of a light source, and which further comprises providing the sealing energy by a light source that acts on the at least one light absorbent layer at the specific wavelengths.
19. The method according to claim 18 , wherein the at least one outer sealant of the pouch or the sealant of the peripheral member is made of a light absorbing material or a thermoplastic layer that is doped with a light absorbing material.
20. The method according to claim 19 , wherein the light absorbing material is a pigment, a polymer resin, fiber or powder that absorbs light.
21. The method of claim 1 which further comprises sealing a pouch fitment to the pouch, wherein the fitment comprises a main body having a base end capable of being attached to the pouch, wherein the base end has a surface coated with a polymer film, the body is made of a material that is sealable to the polymer film, and the body is made of a material that has a melting point that is equal to or higher than that of the polymer film.
22. The method according to claim 21 , wherein the polymer film of the pouch fitment is a metallocene catalyzed polyolefin.
23. The method according to claim 1 , which further comprises filling the pouch with a sensitive food product prior to sealing to form the enclosed pouch and for retaining the product therein; retort processing the filled-sealed pouch; and subsequently sealing the fitment on at least one face of the pouch.
24. The method according to claim 1 , wherein the pouch further comprises a plurality of fitments sealed at different locations on the pouch.
25. A method for sealing a peripheral member onto a closed pouch wherein the pouch has been previously filled with product and sealed to form a sealed enclosure retaining the product therein, comprising:
providing a flexible pouch with an inner sealant sealed that forms a closed enclosure with the product contained therein, and an outer sealant forming at least one external face of the pouch, wherein the outer sealant has a seal initiation temperature that is lower than that of the inner sealant;
providing a peripheral attachment member with at least one sealant that has a seal initiation temperature that is lower than the seal initiation temperature of the inner sealant of the pouch;
contacting the peripheral attachment member and its sealant with the outer sealant at at least one sealing interface area while flattening the pouch at the sealing interface area against the peripheral attachment member with two parts of the inner sealant of the pouch pressed to each other;
applying sealing energy at the sealing interface to provide an intimate seal between the peripheral attachment member and the outer sealant of the pouch, and
releasing energy before the seal initiation temperature of the inner sealant has been achieved.
26. The method according to claim 25 , wherein the pouch comprises a multilayer pouch member with the inner sealant and outer sealant as different layers; and the peripheral attachment member is at least one fitment comprising a bore and a base end, wherein the base end is securely sealed at a sealing interface area onto the outer sealant of the pouch wherein the bore demarcates a portion of the pouch that is puncturable to gain access thereinto.
27. The method according to claim 26 , wherein the sealing interface area of the pouch comprises at least two circumferentially distributed sealing rings with an innermost ring situated between the base end and the pouch at the immediate vicinity of the puncturable pouch portion.
28. The method of claim 1 , wherein the outer sealant covers only selected portions of the pouch.