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Metallized Liner Sealing at High Speeds

2005

Sealing Operation:

At our Tea factory, we pack Tea in small cartons (100gm, 200gm). Tea is first packed in a metallized liner pouch and then inserted into a formed carton. The liner pouch formation involves three Heat Sealing operations. 1. Top Sealing 2. Side Sealing 3. Bottom sealing. Liner is first folded, mechanical driven Heat sealing jaws (see picture) at temperatures (1800 °C for 100 gms pack) then clamp the folded pouch whereby it sealed through fusion.

     

Problem

Currently the machines are running at 60 packets/min whereby each heat-sealing jaw has a maximum of one second to fuse the two surfaces of liner together. We intend to increase the machine speeds by 25 % . However, increasing speeds only slightly above 60 (61 ¡V 62) proper sealing does not occur and we get frequent complaint of leakage.

I am looking for an alternative solution to seal our metallized liner pouches. Solutions could range from suggestions on changing Sealing jaw material to changing the entire sealing system. Any wild idea would be appreciated.

One limitation is the Liner material ¡V which cannot be altered.

Material Specification:

12 microns reverse printed metallized PRT lamination with 38-gsm paper with 4 gsm PEG and extrusion lamination of 20 gsm PE

Overall grammage: 82 gsm (Žb 5 %)

Materials used: PET film PE Paper PEG Printing inks Varnish Laminating adhesive

Sealing Jaw: Mild Steel Heating Medium: Aluminum Rod heater connected to power supply is inserted inside the Sealing jaws (Rods in both jaws).

Khawaja Abdullah
Unilever, Manufacturing - Karachi, Sindh, Pakistan

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This doesn't have much to do with industrial metal finishing except for the fact that the foil is metallized, Khawaja, but hopefully someone will have a suggestion anyway.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005