Note: Descriptions are shown in the official language in which they were submitted.
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~O/~S 1 ? ~;~a~ 1999
USE OF NYLON FILMS IN HOME DRY CLEANING BAGS
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to films for use in dry cleaning bags for in-home use.
Description of the Prior Art
It has been suggested to provide in-home dry cleaning of garments and the like
by utilizing a conventional home dryer. The garments are placed together with
a
material which releases a cleansing agent into a plastic bag. The bag is
placed into a
home dryer and the cleansing agent is released under the action of heat to
clean the
garments.
One concern with this technique is the melting or fusing of the bags due to
hot
spots in the dryer. Although nylon and polyester films in general have been
suggested
as the type of material for the bags, heretofore a satisfactory bag has not
been
achieved.
It would be desirable to provide a method of using a nylon-containing bag in a
home dry cleaning process.
SUMMARY OF THE INVENTION
In accordance with this invention, there is provided in a process for cleaning
fabrics in a conventional automatic clothes dryer wherein the soiled fabrics
are placed
in a plastic bag, and the plastic bag is placed into the drum of the dryer,
the dryer is
rotated and hot air is introduced into the dryer. the improvement wherein the
bag is
formed of a nylon film composition selected from the group consisting of (a) a
blend
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comprising at least one nylon homopolymer and at least one nylon copolymer and
(b)
at least one nylon copolymer. Preferably the nylon homopolymer is nylon 6,
nylon 66
or a mixture of nylon 6 and 66, and the nylon copolymer is a nylon 6/66
copolymer, a
nylon 6112 copolymer or a mixture of such copolymers. Also in accordance with
this
S invention, there is provided a plastic bag for use in dry cleaning, wherein
the bag is
formed from a film selected from the group consisting of (a) a blend
comprising at
least one nylon homopolymer and at least one nylon copolymer and (b) at least
one
nylon copolymer, with the preferred nylon homopolymers and copolymers being
those
mentioned in the prcvious sentence. The nylon composition may also contain
additives such as heat stabilizers, plasticizers, extrusion aids, pigments,
and the Like.
Bags formed from such nylon compositions are resistant to hot spots in a home
dryer,
and are soft, flexible and heat stable.
DESCRIPTION OF THE PREFERRED EMBODIIvvIENTS
1S
The nylon composition used in this invention comprises a blend of at least one
nylon homopolymer and at least one nylon copolymer. Preferably, the nylon
homopolymer is selected from the group consisting of nylon 6, nylon 66 and
mixtures
thereof. '
The nylon homopolymers can be prepared in any conventional manner. For
example, nylon 6 can be prepared by the condensation of epsilon-caprolactam,
and
nylon 66 from the hexamethylene diamine (or a salt thereof) and adipic acid.
2S In the case of nylon 6, the preferred nylon, suchpolymer typically has a
number average molecular weight as measured in formic acid in the range of
about
15,000 to about 40,000, preferably in the range of about 25,000 to about
35,000. The
nylon 6 may be washed, unwashed, or partially washed. The nylon 6 may have
balanced end groups, or be monofunctionally or difunctionaily terminated. In
the case
of nylon 66, polymers of film forming molecular weight are preferred.
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The composition used in this invention further comprises at least one nylon
copolymer. The preferred copolymer is poly(epsiloncaprolactam-hexamethylene
adipamide) copolymer (which is herein also referred to as nylon 6/66
copolymer).
The nylon 6166 copolymer may be formed by any conventional means known to the
art, including but not limited to processes wherein suitable monomeric
constituents,
i.e. caprolactam, hexamethylene diamine, and adipic acid are reacted to form a
copolymer. In a further conventional manner, a salt of hexamethylene diamine,
and
adipic acid is added to caprolactam, and these constituents are reacted to
form a
copolymer.
The relative proportion of nylon 6 to nylon 66 components in the copolymer
may vary widely, with the proportion of nylon 6 segments comprising any amount
between 0.1 % to 99.9% of the nylon 6/66 copolymer structure. The nylon 6166
copolymer may be either a block type copolymer or a random type copolymer.
Preferably the nylon 6 segments of the nylon 6/66 copolymer comprises between
10%
and 35% by weight, most preferably the nylon 6 comprises between 20% and 30%
by
weight of the nylon 6/66 copolymer, with the nylon 66 segments comprising the
remaining amounts.
The nylon 6/66 copolymer preferably has a number average molecular weight
as measured in a 95% sulfuric acid solution, in the range of about 15,000 to
about
40,000, preferably in the range of about 20,000 to about 35,000. The nylon
6/66
copolymer may be washed, unwashed or partially washed.
Another copolymer that can be employed is a nylon 6/12 copolymer which can
be prepared from caprolactam and lauryl lactam, and the relative proportions
of nylon
6 segments to nylon 12 segments can likewise vary widely. As pointed out
above,
mixtures of two or more copolymers may also be employed.
In forming the film compositions used in this invention, the relative ratio of
the nylon homopolymer to the nylon copolymer may be varied over a broad range
so
that the nylon homopolymer comprises between about 0.01% to about 99.99% of
the
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sum of the weights of the nylon humopolymer and nylon copolymer of the film
composition. It is to be understood that the relative ratio of the nylon
homapolymer
to the nylon copolymer in a composition may be purposely varied and seEcctcd
so to
produce a film having particular desired physical properties. Preferably, the
compositions comprise from about 40 to about 80% by weight of nylon
homopolyrner
and correspondingly from about 60 to about 20% by weight of nylon wpvlymer,
and
more preferably about 55 to about 75% by weight of nylon homopolymer and
correspondingly from about 45 to about 25 % by weight of nylon copol3~ncr,
especially where the nylon homopolymer is nylon 6 and the nylon copolymer is
nylon
Z 0 6166.
Films formed fmm blends of nylon 6 and nylon b~'66 copolymer are presently
preferred. Such films are disclosed, for cxacnplc, in U.S. Patent 5,206,309 to
Altman.
15 ~ Alternatively, the films can be formed only from a nylon copolymer, such
as
nylon 6166 and nylon 6!12 and mixtures thereof, with the nylon 6/66 being
presently
preferred.
'fhe films of this invention may contain conventional additives such as
20 coloring agents (e.g., dyes or pigrr~nts), lubricants, mold release abents,
flame
reta,rdants, fibrous and particulate fillers and-reinforeing agents,
ultraviolet and other
Eight stabilizers, heat stabilizers, extrusion aids, plasticizers, nucleating
agents, and
other conventional additives.
25 Blending ox mixing of the constituents which comprise the film compositions
rnay be by any effective means which preferably result/ in uniform dispersion.
All of
thz constituents may be mixed s'unultanaously or separately by a blender,
lrneader,
roll, extruder, or the like in order to assure a uniform blend of the
constituents. 1n the
alternative, the nylon homopolymer and the nylon copolymer may he blended or
30 mixed by mixer, blender, kncadcr, roll, extruder, or the liEcc in order w
assure a
uniform blend ofthe constituents aad resultant mixture is melt-kneaded with
the
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remaining constituents in an exavder to make a uniform blend. A common method
is
to melt-knead a pre»ously dry-blended composition ~~uther in a heated extruder
provided with a singlo-scre~~, or in a heated extruder provided with a singlo-
screw, or
in the alternative, a plurality of screws, extrude the uniform composition
into strands,
and subsequently chop the extruded strands into pellets. In an alternative and
preferred method, the dry-blended composition is provided to a ~~lm forming
apparatus which comprises a heat extruder having at least a single screw,
which
heated extruder melts the constitueats of the dry-blended composition and
forms a
film therefrom through a film die.
14 The film compositions may be formed into films by conventional methods
using conventional film forming apparatus. Conventional methods include the
production of films by blown film techniques, by extruding the film though a
film
forTning dye and optionally casting the film, calendering, and forming a film
forming
composition into a billet and subscquentty skiving a film from a billet. In
one of these
15 . methods a film forming composition is melt blended in an extruder to form
an
ex4rudate which is then extruded through a film forming die onto a casting
roll. In
another method, the film forming apparatus may be one which is referred to in
the art
as blown film apparatus and includes a circular die head thmugh which the film
composition is forced and formed into a filrrx bubble, which is ultimately
collapsed
20 and formed into a film.
The films may optionally be stretched or oriented in any direction if so
desired. In such stretching operation, the film may be stretched in either the
direction coincident with the direction of movement of the film being
withdravr~ from
the casting roll; also referred to in the art as the machine direction, or in
a direction
25 which is perpendicular to the machine direction, and referred to in the art
as the
transverse direction. or in both the machine direction and the transverse
direction_
The films formed by any of the above methods may be of any thickness
desired and includes those which have a thickness less than 2.54'rnm (104
tulle).
30 Preferably, the films have a thickness in the range of about 0.44254 nun
(0.1 mif) and
about 0.254 mm (10 mils); most preferably
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the films have a thickness between about 0.025 mm (1 mil) and about 0.127 mm
(5
mils). While such thicknesses are pccfczzed as providing a readily flexible
film, it is
to be understood that other film thicknesses may be produced to satisfy a
particular
need.
The above-described films are characterized by being soft and flexible as well
as heat stable, so that bags formed froth these filins have the same
attributes which are
panicularly desirable in bags used in hornc dry cleaning pmcesscs. These films
may
be fomaed into bass by any conventional technique. For example, when made by a
blown film process the bubble could be collapsed and one end heat sealc3,
leaving the
other end open. Or a flat cast film can be centerfolded and the sides and one
end heat
sealed. Obviously other techniques can be used to form the bags. These bags
may lx
provided with conventional closing means which arc used to enclose the
contents
prior to use.
In accordance with this invention, bags formed from the above-described films
1 ~ are used in a process of cleaninb fabrics, especially clothes, such as in
a typical home
dryer. The soiled clothes are placed in the bag together with one or more
cleansing
agents and the open ends) of the bag is secured, 'fhe cleansing agent rnay be
incorporated into a carrier, such as a non-woven fiber sheet. The bag is then
placed
into the dnun of a cony ention2l automatic clothes dryer. When the clothes
dryer is
. started, the dnim is rotated and hot air is introduced in the dryer. The
amount of time
which the bag remains in the dryer is dependent upon a number of factors, such
as the
amount of clothes, their degree of soilness, the effectiveness of the
cleansing agent,
the temperature in the dryer and similar considerations. Typical times may
range, for
example, from about ~ minutes to about 40 minutes at aiz temperatures in the
range of
about 50 to about 400°C, for example.
The bags cant be used with any conventional clothes dryer, such as electric,
natural gas or propane gas dryers.
By using films formed from a blend of nylon hom~poiymer and nylon
copolymer, preferably a blend of nylon 6 and ny Ton 6166, to form the clothes
bags the
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bags are resistant to hot spots which may occur during the operation of the
dryer. As a
result, the bag material does not melt during the dry cleaning operation in
the dryer.
In addition, the films of this invention are soft and flexible, as well as
heat stable.
7
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