TECHNICAL FIELD
[0001] This invention concerns improvements in polyester fiberfill material, commonly referred
to as polyester fiberfill, and more particularly to providing polyester fiberfill
in a form that is especially adapted for blending with binder fibers, to such blends
as can be thermally bonded to provide useful bonded products having advantageous properties,
such as bonded batts, and to the resulting bonded batts and other products incorporating
the same.
BACKGROUND OF THE INVENTION
[0002] Polyester fiberfill is used commercially in many garments and other articles, such
as sleeping bags, cushions, comforters and pillows. A particularly useful and desirable
form of polyester fiberfill has a coating of cured polysiloxane, often referred to
as silicone slickener, e.g. as disclosed in Hofmann U.S. Patent No. 3,271,189 and
Mead et al. U.S. Patent No. 3,454,422, because certain desirable properties, such
as hand, bulk-stability and fluffability are improved thereby. Despite the widespread
commercial use of such silicone-slickened-polyester fiberfill, it has long been recognized
that this coating has an important disadvantage, together with the desirable qualities.
As reported by Pamm U.S. Patent No. 4,281,042 and Frankosky U.S. Patent No. 4,304,817,
a silicone coating makes it almost impossible to bond the polyester fiberfill at cross-over
points, especially when blends of only slickened polyester fiberfill and binder fiber
are heat-treated, so as to activate the binder fiber. Any bonds are very poor and
seem to be the result of bonding between residues of any binder fibers that were bicomponent
fibers, whose cores remain after bonding. Thus it is not practical to use such silicone-slickened
fiberfill to form a through-bonded batt or molded article that is properly bonded
and durable, as is desirable in some end-uses.
[0003] The main object of the present invention is to provide a properly through-bonded
batt having advantages of the type that have been obtainable previously only from
unbonded slickened materials, e.g. in hand, in combination with the improved performance
(especially durability) that has only been attainable previously with bonded batts
from "dry" fiberfill. Another object is to improve the resilience and structure stabilization
of slickened fiberfill products. Other objects will appear hereinafter.
[0004] Reference is made here to Jayne et al. U.S. Patent No. 3,702,260. Jayne discloses
surface-modified polyester fiberfill products having improved compressional recovery
and other outstanding properties (see paragraph from column 2 - column 3) and to a
method for providing such fiberfill products. The coating is co-crystallized on the
surface of the crimped polyester staple fiber, and consists of a copolyester comprising
about 20-95% by weight of poly(oxyalkylene) units and about 80-5% by weight of ester
units identical to those present in the polyester staple fiber substrate. Batts of
such coated fibers may be bonded or unbonded and are preferably unbonded (column 2,
lines 57-59). Bonding resins may be applied to the batts to prevent any later fiber
leakage and/or to prevent shifting of the batting in end-use applications, e.g. by
spraying on both sides of the surface in the form of water emulsions, followed by
drying and curing (column 5, lines 15-21). Jayne does not mention binder fibers, and
Jayne's fiberfill has not been used commercially, so far as is known.
SUMMARY OF THE INVENTION
[0005] I have found that, by replacing the existing commercial silicone slickeners with
a hydrophilic coating containing poly(alkylene oxide) chains or segments on the surface
of the polyester fiberfill, it is possible to attain the desired object and other
advantages. Thus such coated polyester fiberfill can be bonded more effectively than
silicon e-slickened fiberfill, e.g. from blends
with binder fiber, and has other advantages in reduced flammability and improved moisture
transport, as will be mentioned hereinafter. It is believed important to ensure that
the hydrophilic coating is "cured" properly onto the polyester fibers, in other words,
that the poly(alkylene oxide) chains are essentially permanently affixed to the surface
of the polyester fibers, i.e. so that they will not be removed by washing or by other
treatments that will be encountered in normal processing or use.
[0006] Accordingly, there is provided an improved polyester fiberfill blend consisting essentially
of, by weight, (a) from about 60 to about 95% of crimped polyester staple fiber, and
(b) complementally, to total 100%, from about 5 to about 40% of crimped staple binder
fiber, comprising a polymer having a binding temperature lower than the softening
temperature of the said polyester staple fiber, characterized in that the said polyester
staple fiber has a coating cured thereto of a slickener consisting essentially of
chains of poly(alkylene oxide).
[0007] Two commercial poly(alkylene oxide) copolymers, involving two different mechanisms
of "curing" are described more particularly below. One is a block copolymer of poly(ethylene
oxide) and poly(ethylene terephthalate) which, when applied to the surface of a polyester
fiber containing repeat units of poly(ethylene terephthalate), and cured at about
170°C, is fixed to the fiber. The mechanism by which it is cured is not fully understood,
but is suggested to be the co-crystallization of the polyester segments on the polyester
fiber. Another curing mechanism is effected by cross-linking poly(alkylene oxide)
chains modified with reactive groups capable of cross-linking with or without the
addition of catalysts or cross-linking agents. Both these routes can be effected by
using commercially available polymers with large segments of poly(ethylene oxide)
and/or poly(propylene oxide), poly(ethylene oxide) being preferred.
[0008] According to one aspect of the invention, therefore, there is provided a polyester
fiberfill blend consisting essentially of, by weight, (a) from about 60 to about 95%,
preferably about 80 to about 90%, of crimped polyester staple fiber and (b), complementally
to total 100%, from about 5 to about 40%, preferably about 10 to about 20%, of crimped
staple binder fibers, comprising a polymer having a melting point lower than that
of the polyester staple fiber, wherein the polyester staple fiber is coated with a
segmented copolymer of poly(ethylene terephthalate) and poly(ethylene oxide) in amount
from about 0.1 to about 1% by weight of the polyester staple fiber.
[0009] According to another aspect of the invention, there is provided a polyester fiberfill
blend consisting essentially of (a) from about 60 to about 95% by weight of crimped
polyester staple fiber and (b) complementally to total 100% by weight, from about
5 to about 40% by weight of crimped staple binder fibers, comprising a polymer having
a melting point lower than that of the polyester staple fiber, wherein the polyester
staple fiber is coated with a modified poly(alkylene oxide) grafted with functional
groups to permit cross-linking, in amount from about 0.1 to about 1% by weight of
the polyester staple fiber.
[0010] Use of these blends makes possible the provision of bonded fiberfill products with
advantages over products that have hitherto been available commercially, as will be
indicated in more detail hereinafter, but can be summarized as:
Improved performance, especially durability, as compared with "dry" (i.e. non-slickened),
fiberfill that has been available commercially.
Soft hand in combination with the structure stabilization and resilience that results
from good bonding.
Good moisture transport.
Lack of flammability, comparable with that resulting from "dry" fiberfill, and such
as I have not obtained with prior commercial silicone-slickened fiberfill.
DETAILED DESCRIPTION OF THE INVENTION
[0011] An important element of the present invention is the use of an appropriate coating
material to provide the desired hydrophilic coating of poly(alkylene oxide) chains
on the polyester fiberfill. As already indicated, some of these materials are available
commercially.
[0012] Coating materials that are suitable for use according to the invention include segmented
copolyesters consisting essentially of poly(ethylene terephthalate) segments and of
poly(alkylene oxide) segments, derived from a poly(oxyalkylene) having a molecular
weight of 300 to 6,000. Several such copolyesters and dispersions thereof are disclosed
in McIntyre et al. U.S. Patent Nos. 3,416,952, 3,557,039 and 3,619,269, and in various
other patent specifications disclosing like segmented copolymers containing poly(ethylene
terephthalate) segments and poly(alkylene oxide) segments. Preferably the poly(alkylene
oxide) will be poly(ethylene oxide), which is also of commercial convenience. One
such product is available commercially from ICI America Inc. as a textile finishing
agent and is sold under the trademark "ATLAS" G-7264. This product is sold in Europe
by ICI Specialty chemicals, Brussels. Another is sold as "ZELCON" 4780, by E. I. du
Pont de Nemours and Company. Other materials are disclosed in Raynolds U.S. Patent
No. 3,981,807. Other suitable materials include modified poly(ethylene oxide)/poly(propylene
oxide) grafted with functional groups to permit cross-linking, e.g. by treatment with
5% by weight of citric acid. Such a product is available commercially from Union Carbide
as "UCON" 3207A. Other materials that may include particularly useful compositions
are disclosed in Teijin EP 159882 and ICI Americas, EP 66994. Further discussion is
given in my copending applications, 86106603.3 (0 203 469) and 87115403.5 filed simultaneously
herewith.
[0013] The coating material can be applied to the polyester fiber either on the crimped
staple or, preferably, on the tow, especially after drawing, in the crimping chamber.
It is cured onto the fiber, by a process which is said to involve co-crystallizing
or crosslinking, depending on the nature of the material. The fiberfill can then be
blended with the binder and packed, or can be packed separately and be blended with
the binder fiber prior to processing the product on standard batt manufacturing equipment.
In any case the batt is generally processed, e.g. in an oven, to bond the binder to
the fiberfill, and to achieve the special properties of the battings described herein.
The coating can also be applied to the fiberfill staple at the end of the process
line, after cutting and prior to packing,
without curing, then be blended with the binder fiber. The blend is then processed on the standard
carding equipment and the curing can take place in the oven at the same time as the
bonding by the binder. These coating materials, however, generally produce better
results when they are applied prior to or during crimping, as the reduced fiber to
fiber friction favors the formation of smoother crimp, which can also contribute to
an improved durability and increased softness, and the bonding appears to be better
as a result of the earlier curing. The binder fiber blend is processed on commercial
carding equipment, cross-lapped, and heat-treated in an oven to bond the fiberfill
and the binder fiber.
[0014] The binders are preferably heat-activated, i.e. they melt or soften at temperatures
some 50°C or more below the melting points of the polyester fiberfill, so that the
bonding does not affect the integrity of the fiberfill itself. Commercially available
sheath/core 50/50 bicomponent binder fibers with a core of poly(ethylene terephthalate)
homopolymer and sheath of a copolymer of poly(ethylene terephthalate/isophthalate)
(60/40), modified to reduce its melting point, have been used with poly(ethylene terephthalate)
fiberfill in the manufacture of the battings of the invention. Although sheath/core
bi nder fibers are preferred, single component binders can also be used with
an improvement over the controls made from the same binder and fiberfill without the
coating. The denier of the binder fiber will generally be between about 3 to about
30 dtex, preferably less than about 20 dtex. Further information about binder fibers
is given in my copending application 87115403.5 filed simultaneously herewith and
in U.S. Patent Nos. 4,281,042 and 4,304,817.
[0015] The fiberfill can be of about 1 to about 30 dtex, can be solid or hollow, with single
or multiple voids, and have a round or an odd cross section.
[0016] The lower deniers are used mainly in applications where the thermal insulation is
an important factor, such as apparel, sleeping bags and special bedding articles for
institutional applications. For these applications the blends of the invention have
shown several advantages over commercially-available polyester slickened batts or
binder fiber blends. The bonded batts have shown a combination of softness and good
bonding with good thermal insulation. The loft and softness have been maintained after
many washings, because of the resistance of the coating to washing, and the excellent
tear resistance of the batts has been shown, as a result of good bonding with the
binder fiber core. The performance of these bonded batts is very surprising, in view
of the previous difficulty in bonding fiberfill slickened with prior art silicone
slickeners. The batts combine this desirable softness with a low flammability such
as is characteristic of batts from non-slickened fibers, and which also contrasts
with the flammability of fibers slickened with silicones.
DESCRIPTION OF TEST METHODS
[0017] Bulk measurements were made conventionally on an Instron machine to measure the compression
forces and the height of each sample pillow or cushion, which was compressed with
a foot of appropriate diameter (10 or 20 cm) attached to the Instron.
[0018] Foot B (20 cm diameter) is used for lower density products (e.g. pillows) with a
maximum pressure of 100N, and suppport bulk (SB) at 30N (representing the height in
cm of the pillow under the weight of an average head). The softness, in this instance,
corresponds to the difference in height (in cm) between the initial height at the
beginning of the second compression cycle (IH₂) and the support bulk; i.e. the (absolute)
softness = IH₂-SB (height at 30N). Softness is sometimes expressed as relative softness,
i.e. as a percentage of IH₂.
[0019] Foot A ( 10 cm diameter) is used for higher density products (e.g. furnishing cushions,
mattresses) with maximum pressure (the same as support bulk, in this instance) at
60N (corresponding to the pressure extended by a sitting person). The softness, in
this instance, corresponds to the difference in height between the initial height
at the beginning of the second compression cycle (IH₂) and the height under 7.5N;
i.e. the (absolute) softness, in this instance, = IH₂-bulk at 7.5N. Again, softness
is sometimes expressed as relative softness, relative to IH₂. The firmness of a cushion
correlates with a strong support bulk, and is inversely related to softness.
[0020] Resilience is measured as Work Recovery (WR), i.e. the ratio of the area under the whole recovery
curve calculated as a percentage of that under the whole compression curve. The higher
the WR, the better the resilience.
[0021] Durability - Several layers of each batting (50 x 50 cm) were stacked to provide a weight of
about 850 g. The number of layers was adjusted to provide pillows with minimal weight
differences. These were covered with a fabric and measured with foot A. The initial
density of the pillows was between 12 and 15 g/l, depending on the bulk of the individual
item. These lower density "pillows" were repeatedly compressed to a maximum pressure
of 1,225 N at a rate of 1,200 cycles/hour for 10,000 cyles. The pillows were remeasured
and the bulk losses calculated.
[0022] Another series of cushions was prepared by stacking a number of layers to product
cushions with 850 ± 15 g. The cushions were compressed using buttons to produce furnishing
back cushions with a density of 25-28 g/1 (depending if the measurement is done on
the crown or in the vicinity of the buttons). These back cushions were submitted to
a stomping test using the shape of a human bottom with an area 37 x 43 cm and a pressure
of 8.8 kPa. The stomping was repeated at a rate of about 1,000 cycles/hour for 10,000
cycles. The cushions were remeasured after the testing and the bulk losses calculated.
[0023] Flammability: Two tests were used:
The methanamine pill test is based on the U.S. Federal Method, Flammability Standard
for Carpets DOC FF 1-70.
The 45 deg. open flame test DIN 54335.
The area destroyed was measured and recorded in both cases, and the rate of propagation
of the flame also recorded in the open flame test.
[0024] Strength: The grab test DIN 53857 evaluates the strength of the bonding. (The results herein
are normalized to a common basis of 200 g/sq.m.).
[0025] Laundry Tests: One layer (40X40 cm) of each batting is quilted (in apparel fabric) and sewn in
the middle. The compression of two layers is measured by Instron (foot B-20 cm diameter),
maximum pressure 240 N). All the samples are washed together in a washing machine
at 40°C for three complete cycles. The samples were remeasured after laundry and the
difference in thickness was calculated.
[0026] The invention is further illustrated in the following Examples. All parts and percentages
are by weight, unless otherwise indicated. All heights are measure in cm, and are
sometimes expressed as "Bulk".
Example 1
[0027] A commercial hollow unslickened polyester fiberfill (6.1 dtex) was coated with 0.35%
by weight (solids) of a hydrophilic slickener by spraying with an aqueous solution
containing 2.8% solids of "ATLAS" G-7264, obtained by diluting the commercial emulsion
(14%) with 5X its weight of water, and then dried in air at room temperature. The
coated staple was blended (85/15) with the above-mentioned sheath/core binder fiber
of 4.4 dtex. This blend was processed to produce a 1 meter wide batt of density about
180 g/sq.m. by superposing four parallel layers without crosslapping. This batt was
heat bonded in a commercial 3.5 m. wide oven at a temperature of 160°C; this heat
treatment had the dual effect of curing the coating to the polyester fiberfill and
of activating the binder sheath of the binder fiber so as to bond the batt. Various
properties of the bonded batt are measured and recorded in tests which clearly demonstrate
the superiority of this item of the invention 2 over control item 1, which was prepared
in exactly the same way from the same basic commercial fiberfill and binder fiber
except that no hydrophilic poly(ethylene oxide)-containing coating was applied. Both
products were processed under otherwise identical conditions, and were bonded by heat-treating
in parallel in the same oven at the same time.
1 - The test batt 2 was much softer and more drapable, but very different from silicone-slickened
products.
2 - Table 1 shows the improved softness and durability over the control.
3 - Bonding to the binder fiber was far better than with 0.3% silicone-slickener,
being 70% of control's strength in machine direction and 50% in the transverse direction,
which is not very significant as there was no cross-lapping in this Example.
4 - Flammability of the test item 2 was very close to the control 1 with 1.0 second
flame duration (= control) and 8.4 cm destroyed length versus 6.0 for the control,
wherein silicone-slickened batting was totally destroyed with flame duration of 40
seconds.
[0028] Although this coate d fiberfill had not been pre-cured (i.e. had
not been heat-treated prior to the bonding treatment), the break strength of the batting
was surprisingly high, being about 70% of that of the control, thereby demonstrating
that good bonding of the coating to the fiberfill had occurred. The following Example
shows the improvements obtained by curing the coating, and using cross-lapped webs.
Example 2
[0029]
1. This is a control described below.
2. The same 6.1 dtex hollow dry crimped commercial polyester fiberfill staple substrate
is coated with 0.35% solids following essentially the procedure described in Example
1, and the coating is then cured onto the fiber by heating the staple at 170°C for
5 minutes. The cured coating fiberfill is then blended with the same sheath/core binder
fiber as in Example 1 in the same proportions (85/15). This blend is processed on
a card and cross-lapper to product a batt of density about 190 g/sq.m., and is bonded
in an oven at 160°C at a speed of 1 m/min. The following Tables compare the properties
of this bonded batt as item 2 with a control batt (item 1) prepared from the same
substrate polyester fiberfill without the hydrophilic coating according to the invention,
and with other batts made as follows:-
3. The same basic polyester fiberfill substrate is coated with 0.35% solids by spraying
with a 20% solution of UCON 3207A (with the addition of 5% of citric acid), and cured
as for item 2 above.
4. This is a control, similar to item 1, but using hollow crimped polyester fiberfill
of 13 dtex, with the same 4.4 dtex binder fiber.
5. This is similar to control item 4, except that the polyesterr fiberfill is coated
with 0.35% of "ATLAS" G-7264 on the 13 dtex fiberfill, and cured as in item 2.
6. This is similar to item 2 above, except that the polyester fiberfill substrate
is coated as a tow under plant conditions, by applying an 8.2% emulsion in water of
"ATLAS" G-7264 to produce the same solids coating of 0.35% on the fiber. The tow was
then relaxed at a temperature of 175°C to cure the coating and set the crimp. The
relaxed tow was cut blended to a cut length of 60 mm with a tow of the sheath/core
binder fiber to produce a blend of 85/15 fiberfill/binder. The blend was converted
into a batt, and the batt was heat bonded under essentially the same conditions described.
7. This item was produced essentially as for item 6, except that the coating was provided
from UCON 3207A, as in item 3.
[0030] To summarize: Items 1 and 4 are controls, items 2, 5 and 6 are coated with ATLAS
G-7264, while items 3 and 7 are coated with UCON 3207A; items 2, 3 and 5 are coated
in staple form, and cured at 170°C, whereas items 6 and 7 are coated in tow form,
before setting the crimp at 175°C; items 1-3, 6 and 7 have fiberfill of dtex 6.1,
whereas items 4 and 5 are of 13 dtex.
[0031] It will be noted that the weights and densities of the batts were not identical.
To get proper comparisons, where indicated, the measurements have been "normalized"
by calculating equivalents all at the same weight of 200 g/m².
[0032] Table 2 gives the compression data for all 7 bonded batts, to show good results,
i.e. good bonding occurred in every case, in contrast with silicone-slickened fiberfill
that cannot be bonded in this manner.
[0033] Tables 3, 4 and 5 give flammability data. It will be noted that none of the items
showed flammability, and the areas destroyed were compatible to controls 1 and 4,
in which unslickened (dry) fiberfill was used, i.e. and fiberfill coatings have not
significantly increased flammability over that of dry fiberfill. In contrast, flammability
tests were made on controls 8 and 9, to show the well-known flammability associated
with silicone-slickened products. Control 8 was a batt entirely of commercial silicone-slickened
fiberfill, otherwise as used in Examples 1 and 2 except for the silicon-slickener.
Control 9 was from a 60/20/20 blend of 60% unslickened
fiberfill, as used in Examples 1 and 2, with 20% slickened fiberfill, as used in Control
8, and 20% of the binder used in Examples 1 and 2; this shows that even the addition
of a minor proportion of silicone-slickened fiberfill causes a very significant increase
in flammability, which is undesirable. The flammability tests did not warrant normalization.
[0034] Table 6 shows the breaking strength measurements. The top set gives the actual measurements
and the different weights of each batt, while the lower set gives calculated measurements
all normalized to the same weight of 200 g/m², since this is a better comparison which
somewhat favors control 1 of lower weight. The significantly superior breaking strength
of preferred item 6 is most impressive. The low figures of items 3 and 7 are speculated
to be because of the nature of the coating, and better results would be expected from
an analogous coating based on poly(ethylene oxide) chains, such as is preferred, but
it is significant that even these coatings give significant bonding, in contrast to
silicone-slickened fiberfill which gives products having virtually no bonding (except
possibly between the residues of the bicomponent binder fibers). These strength tests
are only indirectly related to durability in furnishing, but demonstrates the strong
bonding, which partly explains the good support bulk figures and durability.
[0035] Table 7 shows the results of the delamination test, and again shows the strength
of the bonds between the layers, especially for preferred item 6, which is much better
than the control. This is a very important test, since delamination is a major cause
of failure in some constructions in furnishings and mattresses, and is important also
in sleeping bags and sportswear.
[0036] Table 8 contains two sets of data; in part A the trade control is compared with item
6 in condensed cushions, having a density of 25 to 28 g/l. A comparison of the data
shows that item 6 has a higher height under relatively low loads (IH₂ and 7.5 N),
but a lower bulk at the support bulk level. This reflects the improved softness of
the product which is explained by the reduced fiber to fiber friction. The test item
6 has a much better durability at all loads than the commercial control, although
it has a density which is a little lower. As shown in part B of the Table the differences
in bulk are much higher when considering the same items in the noncondensed deco cushions
or pillows. Despite the considerable differences in density, the test item 6 has equal
bulk losses and maintains after the durability test a much higher bulk. Item 7 is
also showing considerable improvement in bulk durability versus the commercial item,
particularly in the support bulk range. Items 3 and 7, made with the Union Carbide
3207A are also the softest, having the lowest support bulk. This can be of interest
for applications such as sleeping bags, where a high compressibility is required.
Essentially all test items show an equal to better durability than controls, even
if they have a somewhat lower density. The durability advantage of the products of
the invention versus the controls is very significant in both densities and at the
whole practical range of loads. The increased softness and the durability advantage
correspond to a real market need, and the value of the products of the invention is
further increased by the good bonding and nonflammability of these waddings. These
properties are of particular interest for applications such as furnishing and mattresses,
but also sportswear, sleeping bags, etc. These data in Table 8 call for several remarks:
- Bulk and bulk durability are essential in furnishing and mattresses.
- The advantage of the products of the invention, particularly item 6, is in reality
much bigger than one can see from a quick look at the data. It has a better durability
at a much lower density in terms of g/l.
1. An improved polyester fiberfill blend consisting essentially of, by weight, (a)
from about 60 to about 95% of crimped polyester staple fiber, and (b) complementally,
to total 100%, from about 5 to about 40% of crimped staple binder fiber, comprising
a polymer having a binding temperature lower than the softening temperature of the
said polyester staple fiber, characterized in that the said polyester staple fiber
has a coating cured thereto of a slickener consisting essentially of chains of poly(alkylene
oxide).
2. A blend according to Claim 1, characterized in that the polyester staple fiber
is coated with a segmented copolymer of poly(ethylene terephthalate) and poly(ethylene
oxide) in amount from about 0.1 to about 1% by weight of the polyester staple fiber.
3. A blend according to Claim 1, characterized in that the polyester staple fiber
is coated with a modified poly(alkylene oxide) grafted with functional groups to permit
crosslinking, in amount from about 0.1 to about 1% by weight of the polyester staple
fiber.
4. A blend according to any of Claims 1-3, characterized in that the polyester staple
fiber is coated with the slickener in amount from about 0.15% to about 0.6% by weight
of the polyester staple fiber.
5. A process for preparing a bonded batt of polyester fiberfill, wherein polyester
fiber having a coating cured thereto of a slickener consisting essentially of chains
of poly(alkylene oxide) is blended with binder fiber, the blend is formed into a batt,
and the batt is heat-treated to cause the binder fiber to effect bonding at intersections
of the coated polyester fiberfills.
6. A process according to Claim 5, characterized in that the binder fibers are sheath/core
fibers, whereby the sheath provides binder and the core remains in the bonded batt
to provide points for bonding with the coated polyester fiberfill.
7. A process according to Claim 5, characterized in that monocomponent binder fibers
are used, whereby the binder bonds the coated polyester fiberfill at the cross over
points.
8. A process according to any of Claims 5 to 7, wherein the blend is according to
any of Claims 2 to 4.
9. A through-bonded batt of polyester fiberfill of improved durability, and moisture
transport, soft bonding, and low flammability, characterized in that the polyester
fibers are coated with a slickener consisting essentially of chains of poly(alkylene
oxide).
10. A batt according to Claim 9, wherein the slickener is as mentioned in any of Claims
2 to 4.