USE OF NYLON FILMS IN HOME DRY CLEANING BAGS

Abstract: An improved process for cleaning fabrics in a conventional automatic clothes dryer wherein a plastic bag is formed from a blend of at least one nylon homopolymer and at least one nylon copolymer. Preferably the nylon homopolymer is nylon 6 and the nylon copolymer is nylon 6/66 copolymer. The process includes placing soiled fabrics in the plastic bag, placing the plastic bag into the drum of the dryer, and rotating the dryer with the introduction of hot air. This invention also relates to bags formed from such blends which are used in home dry cleaning processes.

Description: 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 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 6/12 copolymer or a mixture of such copolymers. Also in accordance with this 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 previous 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 EMBODIMENTS 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. In the case of nylon 6, the preferred nylon, such polymer 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 difunctionally terminated. In the case of nylon 66, polymers of film forming molecular weight are preferred. 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 6/66 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 6/66 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 sum of the weights of the nylon homopolymer and nylon copolymer of the film composition. It is to be understood that the relative ratio of the nylon homopolymer to the nylon copolymer in a composition may be purposely varied and selected so to produce a film having particular desired physical properties. Preferably, the compositions comprise from about 40 to about 80% by weight of nylon homopolymer and correspondingly from about 60 to about 20% by weight of nylon copolymer, 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 copolymer, especially where the nylon homopolymer is nylon 6 and the nylon copolymer is nylon 6/66. Films formed from blends of nylon 6 and nylon 6/66 copolymer are presently preferred. Such films are disclosed, for example, in U.S. Patent 5,206,309 to Altman, the disclosure of which is expressly incorporated herein by reference. Alternatively, the films can be formed only from a nylon copolymer, such as nylon 6/66 and nylon 6/12 and mixtures thereof, with the nylon 6/66 being presently preferred. The films of this invention may contain conventional additives such as coloring agents (e.g., dyes or pigments), lubricants, mold release agents, flame retardants, fibrous and paniculate fillers and reinforcing agents, ultraviolet and other light stabilizers, heat stabilizers, extrusion aids, plasticizers, nucleating agents, and other conventional additives. Blending or mixing of the constituents which comprise the film compositions may be by any effective means which preferably results in uniform dispersion. All of the constituents may be mixed simultaneously or separately by a blender, kneader, roll, extruder, or the like in order to assure a uniform blend of the constituents. In the alternative, the nylon homopolymer and the nylon copolymer may be blended or mixed by mixer, blender, kneader, roll, extruder, or the like in order to assure a uniform blend of the constituents and resultant mixture is melt-kneaded with the remaining constituents in an extruder to make a uniform blend. A common method is to melt-knead a previously dry-blended composition further in a heated extruder provided with a single-screw, or in a heated extruder provided with a single-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 film forming apparatus which comprises a heat extruder having at least a single screw, which heated extruder melts the constituents of the dry-blended composition and forms a film therefrom through a film die. 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 through a film forming die and optionally casting the film, calendering, and forming a film forming composition into a billet and subsequently skiving a film from a billet. In one of these methods a film forming composition is melt blended in an extruder to form an extrudate 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 a blown film apparatus and includes a circular die head through which the film composition is forced and formed into a film bubble, which is ultimately collapsed and formed into a film. The films may optionally be stretched or orientated in any direction if so desired. In such a stretching operation, the film may be stretched in either the direction coincident with the direction of movement of the film being withdrawn from the casting roll, also referred to in the art as the machine direction, or in a direction 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 thicknesses less than 100 mils. Preferably, the films have a thickness in the range of about 0.1 mil and about 10 mils; most preferably the films have a thickness between about 1 mils and about 5 mils. While such thicknesses are preferred 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 from these films have the same attributes which are particularly desirable in bags used in home dry cleaning processes. These films may be formed into bags by any conventional technique. For example, when made by a blown film process the bubble could be collapsed and one end heat sealed, 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 be provided with conventional closing means which are used to enclose the contents prior to use. In accordance with this invention, bags formed from the above-described films are used in a process of cleaning 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 end(s) of the bag is secured. The cleansing agent may be incorporated into a carrier, such as a non-woven fiber sheet. The bag is then placed into the drum of a conventional automatic clothes dryer. When the clothes dryer is started, the drum 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 5 minutes to about 40 minutes at air temperatures in the range of about 50 to about 400 °C, for example. The bags can 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 homopolymer and nylon copolymer, preferably a blend of nylon 6 and nylon 6/66, to form the clothes bags the 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.

Claims: What is claimed is: 1. In a process for cleaning fabrics in a conventional automatic clothes dryer wherein soiled fabrics are placed in a plastic bag, 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 comprising forming said bag from a nylon film composition 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. 2. The process of claim 1 wherein said nylon film is formed from a blend of at least one nylon homopolymer and at least one nylon copolymer. 3. The process of claim 2 wherein said nylon homopolymer is selected from the group consisting of nylon 6, nylon 66 and mixtures thereof. 4. The process of claim 2 wherein said nylon copolymer is selected from the group consisting of nylon 6/66, nylon 6/12 and mixtures thereof. 5. The process of claim 1 wherein said film is formed from a blend of nylon 6 homopolymer and nylon 6/66 copolymer. 6. The process of claim 5 wherein said blend comprises from about 40 to about 80 weight percent of nylon 6, and correspondingly from about 60 to about 20 weight percent of nylon 6/66 copolymer. 7. The process of claim 6 wherein said blend comprises from about 55 to about 75 weight percent of nylon 6, and correspondingly from about 45 to about 25 weight percent of nylon 6/66 copolymer. 8. The process of claim 5 wherein said nylon 6/66 copolymer comprises from about 10 to about 35 percent by weight of nylon 6 segments and correspondingly from about 90 to about 65 percent by weight of nylon 66 segments. 9. The process of claim 8 wherein said nylon 6/66 copolymer comprises from about 20 to about 30 percent by weight of nylon 6 segments and correspondingly from about 80 to about 70 percent by weight of nylon 66 segments. 10. The process of claim 1 wherein said nylon film is formed from a nylon copolymer. 11. The process of claim 10 wherein said nylon copolymer is selected from the group consisting of nylon 6/66, nylon 6/12 and mixtures thereof. 12. The process of claim 10 wherein said copolymer is nylon 6/66. 13. A plastic bag adapted for use in dry cleaning of fabrics contained therein, said bag being formed from a nylon film selected from the group consisting of (a) a film formed from a blend comprising at least one nylon homopolymer and at least one nylon copolymer and (b) a film formed from at least one nylon copolymer. 14. The bag of claim 13 wherein said bag is formed from a film comprising a blend of at least one nylon homopolymer and at least one nylon copolymer. 15. The bag of claim 14 wherein said bag is formed from a film comprising a blend of nylon 6 and a nylon 6/66 copolymer. 16. The bag of claim 15 wherein said blend comprises from about 40 to about 80 weight percent of nylon 6, and correspondingly from about 60 to about 20 weight percent of nylon 6/66 copolymer. 17. The bag of claim 16 wherein said blend comprises from about 55 to about 75 weight percent of nylon 6, and correspondingly from about 45 to about 25 weight percent of nylon 6/66 copolymer. 18. The bag of claim 15 wherein said nylon 6/66 copolymer comprises from about 10 to about 35 percent by weight of nylon 6 segments and correspondingly from about 90 to about 65 percent by weight of nylon 66 segments. 19. The bag of claim 18 wherein said nylon 6/66 copolymer comprises from about 20 to about 30 percent by weight of nylon 6 segments and correspondingly from about 80 to about 70 percent by weight of nylon 66 segments. 20. The bag of claim 13 wherein said bag is formed from at least one nylon copolymer. 21. The bag of claim 20 wherein said nylon copolymer is selected from the group consisting of nylon 6/66, nylon 6/12 and mixtures thereof. 22. The bag of claim 20 wherein said bag is formed from a nylon 6/66 copolymer. 23. A plastic bag adapted for use in dry cleaning of fabrics contained therein, said bag being formed from a nylon film comprising a blend of nylon 6 and nylon 6/66 copolymer. 24. A plastic bag adapted for use in dry cleaning of fabrics contained therein, said bag being formed from a nylon film comprising a blend of (a) a nylon polymer selected from the group consisting of nylon 6, nylon 66 and mixtures thereof, and (b) a nylon 6/66 copolymer.

Inventors: ALTMAN CARL E, INSEL JAMES F, MOULTON JEFFREY D, ALTMAN, CARL, E., INSEL, JAMES, F., MOULTON, JEFFREY, D.
Applicants: ALLIED SIGNAL INC, ALLIEDSIGNAL INC.
Application year: 1999
Main classification: D06F43
IPC codes: C08G69, C08L77, D06F43