U.S. patent application number 10/148255 was filed with the patent office on 2003-06-19 for beverage infusion packages and materials therefor.
Invention is credited to Jordan, Andrew Kevin, Rose, John Edward, Wardle, Glyn A..
Application Number | 20030113411 10/148255 |
Document ID | / |
Family ID | 10866156 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030113411 |
Kind Code |
A1 |
Rose, John Edward ; et
al. |
June 19, 2003 |
Beverage infusion packages and materials therefor
Abstract
A beverage infusion package (e.g. a tea bag) is formed of
porous, fibrous cellulosic material and has a closure seam produced
by a mechanical compression action without heat sealing. The porous
material contains thermoplastic fibres which are amorphous or are
only partially crystalline and which make the package eminently
suitable for infusion in a microwave oven. The porous, fibrous
material may have a basis weight of 10 to 30 g m.sup.-2 and be
comprises of a single wet-laid layer of an admixture of cellulosic
fibres and the thermoplastic fibres.
Inventors: |
Rose, John Edward;
(Lancashire, GB) ; Jordan, Andrew Kevin;
(Gloucestershire, GB) ; Wardle, Glyn A.;
(Lancashire, GB) |
Correspondence
Address: |
Thomas Q Henry
Woodard Emhardt Naughton Moriarty & McNett
Bank One Tower
111 Monument Circle Suite 3700
Indianapolis
IN
46204
US
|
Family ID: |
10866156 |
Appl. No.: |
10/148255 |
Filed: |
September 23, 2002 |
PCT Filed: |
December 13, 2000 |
PCT NO: |
PCT/GB00/04759 |
Current U.S.
Class: |
426/77 |
Current CPC
Class: |
D21H 13/14 20130101;
D21H 27/10 20130101; B65D 85/808 20130101; D21H 27/08 20130101 |
Class at
Publication: |
426/77 |
International
Class: |
B65B 029/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 1999 |
GB |
9929349.0 |
Claims
1. A beverage infusion package formed of porous, fibrous cellulsoic
material and having a closure seam produced by a mechanical
compression action without heat sealing characterised in that the
porous material contains thermoplastic fibres which are amorphous
or are only partially crystaline.
2. A package as claimed in claim 1 wherein the thermoplastic fibres
are present as a fused or thermally bonded network.
3. A package as claimed in claim 1 or 2 wherein the thermoplastic
has a crystallinity of less then 40%, preferably 10% to 20%.
4. A package as claimed in any one of claims 1 to 3 wherein the
thermoplastic is selected from polypropylene, polyester, polyamide
and high density polyethylene.
5. A package as claimed any one of claims 1 to 4 wherein the
fibrous material comprises 5 to 30% by weight of the thermoplastic
fibres.
6. A package as claimed in claim 5 wherein the porous fibrous
material comprises 10 to 30% by weight of thermoplastic fibres.
7. A package as claimed in claim 6 wherein the porous fibrous
material comprises 15% to 25% by weight of the thermoplastic
fibres.
8. A package as claimed in any one of claims 1 to 7 wherein the
thermoplastic fibres have a thickness in the range 0.5 to 6.0
denier.
9. A package as claimed in claim 8 wherein the thermoplastic fibres
have a thickness in the range 2 to 4 denier.
10. A package as claimed in any one of claims 1 to 8 wherein the
porous fibrous material is hydrophilic.
11. A package as claimed in claim 9 wherein the porous fibrous
material has a water climb value of least 70 seconds as measured by
the time taken for water to rise 1 inch up that material.
12. A package as claimed in claim 10 wherein the porous fibrous
material has a water climb value of 20 to 40 seconds.
13. A package as claimed in any one of claims 1 to 12 wherein the
porous fibrous material has been treated with poly(vinylalcohol)
having a degree of hydrolysis of at least 60%.
14. A package as claimed in claim 13 wherein the poly(vinylalcohol)
has a degree of hydrolysis of at least 80%.
15. A package as claimed in claim 14 wherein the poly(vinylalcohol)
has a degree of hydrolysis of 95% to 99%.
16. A package as claimed in any one of claims 1 to 15 wherein the
porous fibrous material has a basis weight of 10 to 30 g
m.sup.-2.
17. A package as claimed in any one of claims 1 to 16 wherein the
mechanically formed seam has been formed by folding over together
adjacent edges of the porous material and applying a mechanical
compressive force to the folded over edges.
18. A package as claimed in any one of claims 1 to 17 wherein the
seam is a crimped seam.
19. A package as claimed in any one of claims 1 to 18 which is of
the double-chamber type.
20. A package as claimed in any one of claims 1 to 19 which is a
tea bag.
21. A porous fibrous material having a basis weight of 10 to 30 g
m.sup.-2 and being comprised of a single, wet-laid layer of an
admixture of cellulosic and thermoplastic fibres which are
amorphous or only partially crystalline.
22. A material as claimed in claim 21 wherein the thermoplastic
fibres are present as a fused or thermally bonded network.
23. A material as claimed in claim 21 or 22 wherein the
thermoplastic has a crystallinity of less then 40%.
24. A material as claimed in any one of claims 21 to 23 wherein the
thermoplastic is selected from polypropylene, polyester, polyamide
and high density polyethylene.
25. A material as claimed any one of claims 21 to 24 wherein the
fibrous material comprises 5 to 30% by weight of the thermoplastic
fibres.
26. A material as claimed in claim 25 wherein the porous fibrous
material comprises 10 to 30% by weight of thermoplastic fibres.
27. A material as claimed in claim 26 wherein the porous fibrous
material comprises 15% to 25% by weight of the thermoplastic
fibres.
28. A material as claimed in any one of claims 21 to 27 wherein the
thermoplastic fibres have a thickness in the range 0.5 to 6.0
denier.
29. A material as claimed in claim 28 wherein the thermoplastic
fibres have a thickness in the range 2 to 4 denier.
30. A material as claimed in any one of claims 21 to 29 wherein the
porous fibrous material is hydrophilic.
31. A material as claimed in claim 30 wherein the porous fibrous
material has a water climb value of least 70 seconds as measured by
the time taken for water to rise 1 inch up that material.
32. A material as claimed in claim 31 wherein the porous fibrous
material has a water climb value of 20 to 40 seconds.
33. A material as claimed in any one of claims 21 to 32 wherein the
porous fibrous material has been treated with poly(vinylalcohol)
having a degree of hydrolysis of at least 60%.
34. A material as claimed in claim 33 wherein the
poly(vinylalcohol) has a degree of hydrolysis of at least 80%.
35. A material as claimed in claim 34 wherein the
poly(vinylalcohol) has a degree of hydrolysis of 95% to 99%.
Description
[0001] The present invention relates to a beverage inffusion
packages (e.g. tea bags, coffee bags and the like) as well as to
porous, fibrous web materials for use in producing such
packages.
[0002] Beverage infusion packages such as tea bags comprise a
particulate beverage precursor material, e.g. tea leaves or coffee
granules, in a bag, sachet, pouch or the like (all conveniently
referred to herein as a bag) of a porous, fibrous cellulosic
material. This material typically has a basis weight of 10 to 30 g
m.sup.-2 and is often referred to as "tissue" or "tissue paper".
The tissue may be of the "heat seal" or "non-heat seal" type and
the invention is primarily concerned with the production of
beverage infusion packages by techniques which do not involve heat
sealing although a description of "heat seal" tissue is given below
for the sake of completeness.
[0003] "Heat seal" tissue comprises two or more layers wet-laid in
succession one on top of the other. One layer contains only
cellulosic fibres and the other incorporates thermoplastic fibres.
A beverage infusion package is produced from such tissue by forming
the bag such that layers of the tissue incorporating thermoplastic
fibres are juxtaposed and then heat sealed.
[0004] "Non-heat seal" tissue generally (but not necessarily)
comprises a single wet-laid layer of cellulosic fibres produced
from mixtures of well known paper-making fibres which may include
both woody and non-woody materials, e.g. Manila hemp, sisal, jute,
bleached and unbleached soft wood and hard wood species and in some
instances approved synthetic fibres such as viscose rayon. The
material is typically manufactured by the wet laid process on an
inclined wire paper-making machine. The material is generally
treated with classic wet and dry strength chemical enhancing
products, such as CMC (carboxymethyl cellulose) and Kymene
(epichlorohydrin).
[0005] Beverage infusion packages (eg. tea bags) produced from such
"non-heat seal" material incorporate a seam formed by a mechanical
compression action (e.g. involving crimping). Examples of such
packages are those of the "double-chamber" type having attached
string and tag as produced by both Constanta and Perfecta machines
the world over.
[0006] Briefly, such double chamber packages are produced by
longitudinally folding a strip of the non-heat seal tissue so that
the free longitudinal edges are adjacent to each other. These two
edges are then folded over together several times and the fold then
reinforced by means of a pressure controlled toothed wheel known to
those skilled in the art as a Crimp Wheel. The thus formed tube is
then formed into the final double-chamber beverage infusion package
(incorporating beverage precursor material). Such a package
comprises, in effect, a short length of the tube folded
transversely so that the widthwise ends are adjacent to each other
and with the crimped seal extending lengthwise along the inner
sides of the package which is closed at its transverse ends by a
staple to which may be attached a string and tag.
[0007] To produce a beverage, the package is infused with hot
water. This may be done, for example, by immersing the package in
hot water, pouring hot water onto the package, or heating water and
the bag in a microwave oven. This action, of infusing the package
with hot water, causes the bag to inflate and float due to water
bridging the pore structure of the tissue and creating a gas
barrier film entrapping the atmosphere and volatiles generated du
the brewing process. The inflation of the package increases stress
on the mechanically formed seam to a degree dependent, at least in
part on the type and dosage of the beverage precursor material in
the package, e.g. black tea or herbal tea. The stress on the
mechanical seam may be such as to result in failure thereof causing
tea leaves, coffee grounds or the like to be released into the
beverage and this is obviously undesirable. The problem of seam
failure occurs when the wet crimp strength of the scam is not
sufficiently high and is exaserpated in the microwave method of
infusing the beverage where the extended period of energy input
(e.g. for two minutes) increases the stress placed on the
mechanical seam both in a cold and hot environment and has a
detrimental effect on most classical wet and dry chemical systems
employed.
[0008] It is an object of the present invention to obviate or
mitigate the above mentioned disadvantages.
[0009] According to a first aspect of the present invention there
is provided a beverage infusion package formed of porous, fibrous
cellulsoic material and having a closure seam produced by a
mechanical compression action without heat sealing characterised in
that the porous material contains thermoplastic fibres which are
amorphous or only partially crystalline.
[0010] Thus in accordance with the first aspect of the invention
the beverage infusion package is formed from a material
incorporating fibs of a thermoplastic which is amorphous or (more
preferably) partially crystalline. We have found that such fibres
produce a significant enhancement of mechanical seam integrity. The
dry strength of the seam is sufficient to prevent the package
bursting open and spilling the beverage precursor material during
manufacture, packaging, delivery and or consumer use. Moreover, the
wet crimp strength is such that there is no significant seam
failure when infusion packages in accordance with the invention
either when boiling water is poured onto the package to brew the
beverage or when the infusion package is heated with water in a
microwave oven.
[0011] We do not wish to be bound by theory but we believe that the
success of the present invention is attributable to several
reasons. Firstly, the thermoplastic fibres in the paper at the
opposite sides of the seam are bent and form an inter-locked
synthetic matrix which is impervious to boiling water and microwave
energy. Secondly, the fact that the thermoplastic fibres are
amorphous or only partially crystalline ensures that fibre recovery
is limited which enables the crimped seam to be maintained under
high stress in a hot aqueous environment.
[0012] The invention is particularly effective in the case where
the mechanically formed seam is formed by folding over together
adjacent edges of the porous material and applying a mechanical
compressive force to the folded over edges. The compressive force
may be applied by crimping, e.g. using a pressure controlled
toothed wheel (a so-called Crimp Wheel). In such a case the fibres
are crimped together providing an additional degree of interlocking
and therefore enhancement of seam integrity.
[0013] The beverage infusion package of the invention may for
example be a tea bag, e.g. of the double-chamber type, but is also
applicable to other beverages, e.g. coffee.
[0014] The porous fibrous material will generally have a basic
weight of 10 to 30gm.sup.-2, more typically 10 to 20 gm.sup.2, e.g.
10-13 gm.sup.2. For preference, the material will comprise 5 to
30%, more preferably 10% to 30%, and ideally 15% to 25% by weight
of the thermoplastic fibres.
[0015] The material may be formed by conventional paper-making
techniques by laying a suspension comprised of cellulosic and
thermoplastic fibres onto a papers forming fabric of a paper-making
machine (e.g. an inclined wire paper-making machine) and
withdrawing water from the laid suspension through the fabric.
[0016] Cellulsoic fibres forming the suspension may be those
conventionally used for producing non-heat paper for beverage
infusion bags and may include both "woody" and "non-woody"
materials such as manila hemp, sisal, jute, and bleached and
unbleached soft wood and hard wood species.
[0017] Generally the relative amounts of non-woody material to
woody material will be 40 to 80 parts of non-woody material to 20
to 60 parts woody material.
[0018] The material may be produced by laying successive layers of
suspension (possibly of differing composition) one on top of the
other, e.g. as described in WO-A-9601839. It is however more
preferred that the material comprises only a single layer of the
cellulosic and thermoplastic fibres. This is an important aspect of
the invention in its own right and therefore according to the
second aspect of invention there is provided a porous fibrous web
material having a basis weight of 10 to 30 gm.sup.-2 and being
comprised of a single, wet-laid layer of an admixture of cellulosic
and thermoplastic fibres which are amorphous or are only partially
crystalline.
[0019] Material in accordance with the second aspect of the
invention is suitable, and primarily intended for, producing
beverage infusion packages in accordance with the first aspect of
the invention, However, the material is also suitable for any use
where a porous, high wet strength, mechanically crimped seam is
required.
[0020] Preferably the crystallinity of the thermoplastic fibres is
less than 40% to reduce fibre recovery to 10% which enables the
mechanical seam to be retained under high stress in a hot aqueous
environment. More preferably the crystallinity is 10-20%.
[0021] Examples of thermoplastics which may be used are
polypropylene, polyester, polyamide 6, 66, 11, 12 and high density
polyethylene. Blocked or random copolymers or terpolymers of
propylene and ethylene may also be used.
[0022] The thermoplastic fibres will preferably have a thickness of
0.5 to 6.0 denier although best results will generally be achieved
with fibres in the 2 to 4 denier range.
[0023] The length of the thermoplastic fibres may be 0.5 mm to 12
mm, preferably 3 mm to 6 mm and more typically 5 mm.
[0024] Preferably the thermoplastic fibres in the web have been
"fused" or thermally bonded together, at a temperature greater tan
the crystalline melt temperature of the thermoplastic fibres.
[0025] Such "fusing" can provide two effects. Firstly, the
crystallinity of the thermoplastic fibres from which the web is
manufactured may be reduced to a desired value. Thus for example
the fibres may initially have significant crystallinity (e.g.
greater then 50% and possibly greater than 80%) and this
crystallinity may be reduced by the heat treatment to the preferred
value of, say, 10-20%. Secondly the fibres become fused together at
their junctions (or points of contact) to provide a cohesive
reinforced crystalline matrix. The affect of fusing the
thermoplastic web further improves the dry and wet crimp
functionality by increasing web elasticity specifically in the
cross machine direction orientation. However, the thermoplastic
fibre can be used in an un-fused state, however, the improvement in
wet crimp recovery is less, due to the higher recovery rate of the
fibre to flexing and can lead to higher failure rates at the
mechanical crimp fin seal during microwave brewing.
[0026] The thermoplastic fibres form which the web is produced may
be of isotatic polypropylene drawn into fibres having a degree of
crystallinity of at least 75%, the crystallinity subsequently being
reduced during the above described "fusing" step.
[0027] The crystallinity of the fibres may be assessed
colorimetrically. Thus, when polypropylene (a preferred
thermoplastic for use in the invention) is crystallised from the
melt and drawn under stress the arrays of crystallised, known as
spherilites, become highly orientated in the longitudinal direction
of the filament. Due to the highly orientated spherilites the
fibres when viewed under polarised light show a distinctive bright
yellow colouration demonstrating a degree of crystallinity.
[0028] When polypropylene is used in the current invention and is
thermally bonded at a temperature greater than the crystalline melt
temperature of the polypropylene the spherilites become more
randomly orientated and under polarised light show only slight
evidence of yellow colouration.
[0029] It is recognised for current beverage infusion bags formed
having a seal produced by mechanical compression that if the
initially formed dry seal is below a predefined value hen the
strength of the crimp in the wet state (wet crimp) will be
insufficient. However the current invention can produce a more than
adequate wet crimp seal for microwave use for only a small increase
in wet crimp strength.
[0030] The material of the second aspect of the invention or any
other material from which a beverage infusion package in accordance
with the first aspect of the invention is to be produced may be
treated (by either addition to the wet pulp stock suspension or at
a size press unit) with agents known per se for imparting wet and
dry strength. e.g. carboxymethyl cellulose (CMC) and
epichlorohydrin (e.g. available under the name KYMENE (Trade Mark).
These agents may be used such as to provide at least 1% by weight
thereof on the material.
[0031] Particularly in the case where the web is treated with
epichlorohydrin, it is preferred that it is also treated with
poly(vinyl alcohol) which acts to increase dry strength and (in
conjunction with epichlorohydrin) improves wet crimp strength. The
poly(vinyl alcohol) is preferably one having a degree of hydrolysis
of at least 60%, more preferably at least 80%, and most preferably
95% to 99.9%.
[0032] The poly(vinyl alcohol) may for example of the type known as
the "super-hydrolysed" variety, e.g. as available under the AIRVOL
(Trade Mark) as available from Air Products.
[0033] Levels at which the poly(vinyl alcohol) will be applied to
the web will generally be in the range 0.5 to 4% by weight
typically 1.0 to 2% by weight
[0034] It is possible for the porous fibrous material (from which
the infusion package is produced) to be relatively hydrophilic such
that, during brewing of the beverage, the bag rapidly wets out and
sinks in the brew liquor providing a satisfactory infusion rate.
The hydrophilicity of the porous fibrous material may be measured
by a water climb test in which the lower end of a vertically
disposed strip (1".times.5" (2.54.times.12.70 cm)) of the material
is dipped into water and then time taken for the water to rise 1"
(2.54 cm) up the material is measured. In accordance with the
invention it is preferred that the porous, fibrous material has a
water climb value of less than 70 seconds, e.g. 20 to 40 seconds,
ideally about 30 seconds.
[0035] A further means of measuring, hydrophilicity is by the Water
Drop Test in which a micro syringe is used to drop a small bead of
water at ambient temperature on to a single layer of the infuser
web, which is supported around its perimeter by a small diameter
ring, typically 2" (5.08 cms). The time taken for the droplet of
water to spread out and collapse into the infuser web, i.e. zero
contact angle, is timed by means of a stopwatch. It is preferred
that the porous, fibrous material has a value in the Water Drop
Test of less than 10 seconds, more preferably less than 5 seconds,
and even more preferably less than 1 second.
[0036] The hydrophilicity of the web may be achieved by treatment
with epichlorohydrin and poly(vinyl alcohol).
[0037] The invention will be illustrated by the following
non-limiting Examples in which porous fibrous material (in
accordance with the second aspect of the invention) were produced
as illustrated in Examples 4 and 5. Examples 1-3 represent
comparative materials.
EXAMPLE 1-(COMPARATIVE)
[0038] A standard NHSTB 12.3-13.0 gsm infuser web was produced on
an inclined pilot paper machine from 70% Manila and 30% soft wood
and bonded with 1% Kymene and 2% CMC. This material was then slit
to 94.3 mm coils and conditioned in a humidified laboratory to the
typical industry standard of 7-8% moisture content, as low moisture
is knows to significantly affect conversion parameters
adversely.
EXAMPLE 2-(COMPARATIVE)
[0039] A USA style latex NHSTB prototype at 12.3-13.0 gsm infuser
web was produced in the inclined pilot paper machine from 70%
Manila and 30% softwood and bonded with 1% Kymene and 13.5% of a
co-polymer of Ethyl and Butyl acrylate latex. This material was
then slit to 94.3 mm coils and conditioned in a humidified
laboratory to the typical industry standard of 7-8% moisture
content.
EXAMPLE 3-(COMPARATIVE)
[0040] A European style latex NHSTB prototype at 12.3-13.0 gsm
infuser web was produced on the inclined pilot paper machine from
60% Manila, 30% softwood, 10% hardwood and bonded with 1% Kymene
and 13.5% of a co-polymer of methacrylate Styrene Butadiene latex.
This material was then slit to 94.3 mm coils and conditioned in a
humidified laboratory to the typical industry standard of 7-8%
moisture content.
EXAMPLE 4-(INVENTION)
[0041] A standard NHSTB 12.3-13.0 gsm infuser web was produced on
the inclined pilot paper machine from 55% Manila and 30% softwood,
15% Polypropylene (3 denier, 5 mm) and bonded with 1% Kymene.
During the production of this material the polypropylene was
"fused"/"thermally bonded" to an amorphous state by taking the
polymer past its crystalline melt temperature. This material was
then slit to 94.3 mm coils and conditioned in a humidified
laboratory to the typical industry standard of 7-8% moisture
content.
EXAMPLE 5-(INVENTION)
[0042] A standard NHSTB 12.3-13.0 gsm infuser web was produced on
the inclined pilot paper machine from 55% Manila and 30% softwood,
15% polypropylene (3 denier, 5 mm) and bonded with 1% Kymene and 2%
PVOH (Airvol 165). During the production of this material the
polypropylene was "fused"/"thermally bonded" to an amorphous state
by taking the polymer past its crystalline melt temperature. This
material was then slit to 94.3 mm coils and conditioned in a
humidified laboratory to the typical industry standard of 7-8%
moisture content.
[0043] The materials produced in Examples 1 to 5 were subjected to
a number of Tests as detailed below. Unless otherwise stated, tea
bags for use in the Tests were produced on a Constanta NHSTB
Machine at a speed of 140 bags/min. The bags were dosed with 1.8
grams of black tea equally between the two chambers and the
enclosure made as standard using a steel staple.
[0044] Test 1- Microwave Crimp Failure
[0045] The energy out put of microwaves has increased dramatically
over the recent couple of years and is now typically 850-1200 watts
for domestic appliances. It has also been observed that the energy
inputted to the fusion packet during the typical brew cycle can
also vary for a given microwave wattage depending on make, model
and whether the microwave is "cold" i.e. the first use or is "hot"
i.e. the second and subsequent uses during a sustained period.
[0046] The test regime that has been adopted to evaluate the above
observation and to provide a broad indication of infusion material
acceptability over a range of conditions is outlined as
follows:
[0047] Microwave used in a 1200 watt variable power domestic unit
made by Philips Industries.
[0048] Water used is drawn from a domestic cold water supply common
to the region
[0049] 5 replicate are performed with out any cool down ties
between tests.
[0050] The bags are placed into 175 ml of water at ambient
temperature, contained by a grade B 250 ml laboratory beaker.
[0051] The beaker is observed, through the glass door, during both
microwaving and then in removal from the microwave and following
recorded:
[0052] Does the crimp fin seal fail during the brewing process as
indicated by tea leaf present in the beaker.
[0053] When the tea bag is removed and the top stapled seal opened
does the crimped fin seal show signs of deforming such that the bag
is on the verge of opening.
[0054] The test is then repeated immediately for the next replicate
until the 5 samples have been tested.
[0055] The microwave is then allowed to cool down to ambient
temperature and the test is then repeated at the next power setting
(90%) until the fill range of setting (60-100%) have been evaluated
for a given sample type,
[0056] The results are shown in Table 1.
1 Microwave Crimp Failure Vs Energy Input Table 1 Ex 2 Ex 3 Ex 4 Ex
5 Ex 1 Latex Latex Micro- Micro- % Energy JRC Product Product wave
wave Input NHSTB USA EU NHSTB NHSTB 100 Total Total Total No
failure No failure failure failure failure 90 Total Total Total No
failure No failure failure failure failure 80 Total Total Total No
failure No failure failure failure failure 70 Total Open on No
failure No failure No failure failure inspection 60 Open on No
failure No failure No Failure No failure inspection
[0057] Test 2-Tea Sift
[0058] The amount of tea that is allowed to pass through the
infuser web is of critical importance as it limits how the tea bag
producer can blend/mill the tea used. This impacts on both the
final infusion rate of the tea bag and how much tea is lost into
the package during transport (Tea sift).
[0059] To assess comparatively die differences between infuser
tissues the following test regime has been adopted and is outlined
as follows:
[0060] 3 discrete size ranges of sand are used (75-106, 106-150,
150-221microns)
[0061] The sand used is of the type produced by shot blasting and
is fractionated in-house using graduated sieves.
[0062] The test is performed by weighing out 10.0 g.+-.0.05 g of
the sand and placing it in a catchpot for each of the sand
fraction.
[0063] The catchpot is then covered by a square of the test tissue
across the opening
[0064] The catchpots are then stacked one on top of cach other to
form a column.
[0065] The stack is then carefully inverted.
[0066] The stack is then placed in an Endecote vertical shaker and
vibrated for 10 minutes.
[0067] When the time is finished the catchpot stack is removed and
carefully inverted so the tissue sample are again on top of each
catchpot.
[0068] The residual sand in each catchpot is measured and the
percentage "sift" of the paper determined by the product of the
original and final sand weights.
[0069] The results are recorded under the appropriate sand range
and the average "sift" ranking is established by taking the mean
value of the 3 sand range results.
[0070] The results are shown in Table 2.
2 % Tea Sift Data Table 2 Ex 2 Ex 3 Particle EX 1 Latex Latex Ex 4
Ex 5 Size JRC Product Product Microwave Microwave Microns NHSTB USA
EU NHSTB NHSTB 75-106 93.4 64.8 67.2 82.9 29.2 106-150 21.9 31.7
30.1 60.5 37.5 150-212 4.6 8.3 6.2 17.2 10.9 AVET 40.0 34.9 34.5
56.9 42.53
[0071] Test 3- Tea Infusion
[0072] The speed at which a specific tea blend infuses (Brews) is
reliant on the impact of infusion packets and is obviously of key
importance to the consumer.
[0073] To assess comparatively the impact in infusion rate of
different infuser tissues the infusion rate is evaluated by
measuring the colour change of the brew liquor of a period of time,
typically 5-6 minutes, by colourimetry The following test regime
has been adopted and is outlined as follows:
[0074] The tea bag is contained in a holding cage, to maintain
submergence in the water, is placed into a 1000 ml beaker
containing a photometer probe and a magnetic stirrer. 700 ml of
boiling de-ionised water is poured into the beaker at which point
the test begins.
[0075] The initial (Time=zero seconds) photometer reading is taken
and then at intervals until the end of the test at 270 seconds.
[0076] The brew liquor in the beaker is maintained at 85.degree. C.
during the test by means of a heating plate.
[0077] The results are shown in Table 3.
3 Infusion Data Table No. 3 Light Transmission Ex 4 Ex 5 Infusion
Ex 2 Ex 3 Micro- Micro- Time Ex 1 Latex Latex wave wave Sec NHSTB
Product Product NHSTB NHSTB 30 0.129 0.015 0.13 0.125 0.132 90
0.523 0.321 0.299 0.481 0.300 120 0.639 0.541 0.442 0.588 0.642 150
0.721 0.690 0.569 0.669 0.729 240 0.895 0.807 0.797 0.835 0.918 270
0.935 0.859 0.853 0.968 0.958
[0078] Test 4 Hydrophilicity
[0079] Water Climb and Water Drop Tests were conducted as described
above.
[0080] The results are shown in Table 4.
4 Water Climb & Water Drop, Test Data Table 4 Ex 2 Ex 3 Ex 4 Ex
5 Water Water Ex 1 Latex Latex Micro- Micro- Climb to Drop Test JRC
Product Product wave wave 1" (Secs) (Secs) NHSTB USA EU HSTB HSTB
30 <1 .check mark. .check mark. 50 <60 .check mark. 300
>250 .check mark. 400+ >450 .check mark.
[0081] Test 5- Wet Crimp
[0082] The dry strength of the crimp fin seal is of critical
importance to both dry functionality in manufacture, packaging and
end use, while the wet integrity of the crimped fin seal is
obviously the key factor in brewing functionality.
[0083] To assess comparatively the differences between dry and wet
crimp strengths of different infuser tissues, the following test
regime has been adopted:
[0084] Tea bags are manufactured without tea being dosed to the
individual bags,
[0085] The top seal is cut off 5 bags which are opened flat.
[0086] A 50 mm section is cut from ostensibly each chamber side of
the bag. Each section is then cut to give the side of the chamber
section containing the crimped fin seal alone.
[0087] The sample is then loaded into the jaws of a tensile testing
machine, such that the crimped fin seal is situated between the
jaws.
[0088] A standard tensile assessment of the seal is then under
taken and the results reported as grams/50 mm.
[0089] The wet crimp test is identical to the above except that
once loaded into the jaws of the tensile tester the sample is
sprayed lightly with a mist of water at ambient temperature.
[0090] The results are shown in Table 5.
5 Wet Crimp Data Table No. 5 Typical Crimp Tensile Range (g/50 mm)
Ex 1 Ex 2 Ex 3 Ex 4 Crimp Type NHSTB Latex Product Latex Product
Microwave Dry 125-200 160-242 110-165 123-300 Wet 9-13 20-36 16-21
17-25
[0091] Test 6-Hot Water On Cup Brew
[0092] Herbal teas are of high bulk for a given grammage. The
amount of tea dosed to herbal tea is still typically 1.5 g-2.0 g
however the tea expands significantly during brewing and contains
significant volumes of both ambient atmosphere and gases produced
during the brewing process. The effect of this is to put an
increased stain on the crimped fin seal, which with standard paper
grades causing a rupture of this seam.
[0093] To assess comparatively the differences between infuser
tissues the following test regime has been adopted and is outlined
as follows:
[0094] Tea bags are manufactured without tea being dosed to the
individual bags,
[0095] 2 grams of peppermint tea is dosed between the two chambers
and the top enclosed as standard with a steel staple.
[0096] The bags are placed in a 500 ml b grade laboratory
beaker
[0097] 200 ml of boiling domestic fresh water is poured on to the
bag to determine if the bag:
[0098] Inflates (Balloons)
[0099] The crimped fin seal ruptures, as defined by tea leaves in
the brew liquor.
[0100] The test is normally the result of 5 replicates and is
reported as a percentage of the total tested.
[0101] The results are shown in Table 6
6 Hot Water On Cup Brew Test Table 6 Ex 2 Ex 3 Ex 1 Latex Latex Ex
4 Ex 5 Pour on Typical Product Product Microwave Microwave Test
NHSTB US EU HSTB HSTB Ballooning 100% 20% 30% 100% 100% Open on 0%
20% 20% 5% 5% Inspection Burst 90% 10% 15% 5% 0%
* * * * *