Food or edible material: processes – compositions – and products – Foraminous material infusion type – or foraminous container...
Patent
1998-04-28
2000-10-31
Bhat, Nina
Food or edible material: processes, compositions, and products
Foraminous material infusion type, or foraminous container...
426 79, 426 84, 4283166, 162 91, 162 98, 162141, 162213, B65B 2902, B32B 702, D21H 2738
Patent
active
061398837
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a fibrous, porous web material of the non-heat seal type intended for use particularly, but not exclusively, for the production of infusion sachets for brewing beverages such as tea and coffee.
Infusion sachets for brewing beverages (e.g. so called teabags and coffee bags) are generally produced from either "heat seal" or "non-heat seal" fibrous porous web material (hereinafter also referred to as paper for convenience). Heat seal paper generally comprises two layers. One of these two layers includes fusible polymeric fibres which allow two layers of the paper to be heat sealed together in the production of infusion bags. The other layer is present as an insulation layer to prevent polymer (in the other layer) sticking to heated dies during conversion of the paper to produce an infusion sachet. In contrast, a non-heat seal paper (which normally has a basis weight in the range of 9 to 18 g m.sup.-2 and typically about 12.3 g m.sup.-2) is generally comprised of a single layer comprised of vegetable fibres which does not incorporate fusible polymeric fibres. Thus, as its name suggests, non-heat seal paper cannot be heat sealed to itself. Infusion bags are produced from such paper by crimping or otherwise mechanically securing two layers of the paper together.
There is however a problem in some areas with conventional non-heat seal papers for use in the production of teabags in that fine tea dust (resulting from interaction of tea leaves during processing thereof) or fine particles of tea have a tendency to pass through the paper to the outside of the teabag. Since teabags are generally packaged in boxes or other types of "outer" packaging, the fine tea particles or dust are "loose" in the packaging and this is undesirable from the aesthetic viewpoint.
One possibility for overcoming this problem would be to increase the percentage of finer fibres (preferably hardwood fibres) in the stock from which the single ply paper is produced. This would result in a paper with smaller pores thus reducing the amount of fine tea or tea dust which can pass through the paper.
The increase of hardwood fibres or other short fibres in the single layer to achieve the required pore size distribution would, however, affect overall paper strength to the extent that the paper would not have sufficient strength for manufacture into infusion bags. A further disadvantage which would be associated with the use of hardwood fibres in the layer would be the incidence of pin-hole generation through air entrainment.
A further disadvantage of conventional non-heat sealpaper is that it is difficult to provide a pattern in the paper using conventional methods. The patterns which are desired are those which can readily be produced in papers of the "heat seal" type. Such patterns may comprise a matrix of perforations which are formed through the web and which are intended to allow the passage of water therethrough. Alternatively the pattern may be either a logo or other marking indicating the manufacture of either the paper or infusion sachets prepared therefrom.
Such perforations are generally formed in heat seal paper by one of two methods. Firstly the perforations may be formed by a pattern of projections (known as knuckles) on the wire on which the fibrous suspension (used for producing the paper) is produced during the "wet laying" operation. Secondly the pattern may be formed in the web by fluid jets, e.g. using a PERFOJET apparatus.
Non-heat seal paper is generally comprised of a single layer (as indicated above) and typically has a basis weight of 12.3 g m.sup.-2. The patterning methods discussed above cannot generally be used for such non-heat seal paper. Thus, if the paper is formed on a wire provided with knuckles, the paper cannot be easily released from the wire. This is believed to be due to the fact that the cellulosic fibres of the paper are more cohesive because of their greater contact with the wire and their wetness (and as such are therefore more difficult to release) than the cylindrical synthe
REFERENCES:
patent: 2531594 (1950-11-01), Abrahams
patent: 2928765 (1960-03-01), Kurjan
patent: 3386834 (1968-06-01), Noiset et al.
patent: 3529925 (1970-09-01), Thomas et al.
patent: 3640727 (1972-02-01), Heusinkveld
patent: 4582666 (1986-04-01), Kenworty et al.
patent: 4801464 (1989-01-01), Hubbard, Jr.
patent: 5288402 (1994-02-01), Yoshida
patent: 5443606 (1995-08-01), Hassenboehler, Jr. et al.
patent: 5496573 (1996-03-01), Tsuji et al.
patent: 5500167 (1996-03-01), Degen
patent: 5780369 (1998-07-01), Allison et al.
Alston Joyce
Gbur Ivan
Tomkinson Brian
Bhat Nina
J. R. Crompton Limited
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