Infusion packets and a process for their manufacture

Abstract

The present invention relates to a process for the manufacture of infusion packets, the process comprising: • (a) providing a first sheet of thermoplastic material (2) which is porous or non- porous; • (b) thermoforming portions of the first sheet into a three-dimensional shape; • (c) providing a second sheet of material; • (d) dosing an infusible substance into the thermoformed portions of the first sheet or onto the second sheet; • (e) sealing the first and second sheets together to form pockets containing the infusible substance such that each pocket includes at least one thermoformed portion of the first sheet; • (f) severing the pockets at the seals to form infusion packets each having a chamber containing the infusible substance,

Description

TECHNICAL FIELD[0001]The present invention relates to infusion packets. More particularly, the present invention is directed towards the manufacture of infusion packets (such as tea bags) having a three-dimensional shape.BACKGROUND[0002]In the past, conventional infusion packets (e.g. tea bags) have typically been flat, comprising a single chamber filled with infusible material (e.g. leaf tea, herbal mixtures). Such packets are essentially flat and thus restrict the movement of the infusible material within the packet to substantially two dimensions. As a result, the infusion performance of these infusion packets is limited.[0003]U.S. Pat. No. 3,549,381 discloses a tea bag comprising tea leaves enclosed in an impervious, flexible, thermoplastic protective film, at least a portion of said film having a regularly spaced embossed pattern on at least one surface which has been drawn sufficiently to develop a preferential weakness in one direction. The tea bag is impervious until it is s...

AI Technical Summary

Benefits of technology

Technical effects: The patent describes a method for making a porous infusion packet by using a non-porous film that is thermoformed and then sealed. The process creates holes in the film that allow liquids to pass through, while also stretching the film without compromising the holes. The resulting material is permeable to water and can be sealed using heat or other methods like ultrasonic sealing. The technical effect of this process is a more efficient and effective infusion packet that allows for better absorption of liquids.

Problems solved by technology

However, materials conventionally used to manufacture infusion packets are often not suitable for thermoforming.

Firstly, infusion packets are commonly made of paper, which is not thermoformable.

Secondly, even if they are made from a thermoformable material, the porosity and thinness of the material makes thermoforming a challenge.

Very thin material is liable to tear under the stresses applied, particularly when being formed into a three-dimensional shape comprising sharp features.

There is also the possibility that the thermoforming process will increase the size of the perforations and / or holes in the material to such an extent that fine particles of infusible material will leak out of the packet.

Thus it would seem that thermoforming is not a practical method of generating infusion packets.

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