Non-Woven Fabric Construction for Detergent Pouch

1. Field of the Invention

This invention relates to a non-woven fabric construction and, more particularly, to a non-woven material especially adaptable for use as a detergent pouch.

2. Description of the Prior Art

Many users of automatic laundry machines prefer to use pouches of detergent because such provides ease of use, reduces waste of detergent by providing a pre-measured amount of detergent compatible with the capacity of the average washing machine, while also eliminating contact of the detergent with the hands of the user, and facilitates general neatness of the laundry area.

However, in the past, various difficulties have arisen with the pouches of the prior art since the fabric of some pouches fail to hold detergent powder therein, while others have openings too small to allow for full passage of the detergent into the washing liquid.

U.S. Pat. No. 4,188,304, discloses the use of laundry pouches having water sensitive side seals which cause the construction to open at one or more seams when immersed.

In another U.S. Pat. No. 4,555,354, there is taught the use of mechanically weak seals which become unsealed due to the agitating action of the washing machine. Rough handling of this product during transportation and merchandising can lead to failure of the seals prematurely.

U.S. Pat. No. 4,348,293 relates to water soluble sheets or coatings adhered to the porous non-woven substrate which, when dissolved, permit the transport of the detergent powders through the intersticed spacings.

The present invention overcomes the disadvantages of prior art pouches by utilizing an advantageous non-woven material, which is mechanically and chemically treated to prevent outward passage of even the smallest particles of conventional detergents while dry, yet in which the interstitial spacing is widely enlarged when disposed in laundry liquid.

To this end, a non-woven sheet of non-water sensitive material or hydrophobic material, such as polyester or polypropylene, is provided. Then, this material is compressed and flattened, while being simultaneously bonded, to maintain this shape by a water sensitive binder. The material is then manufactured into a pouch, which is filled with detergent powder. When immersed in the liquid of a laundering machine, the binder dissolves and the compressed and flattened material resumes substantially its original shape permitting passage of detergent powder outwardly of the pouch.

FIG. 1 is a plan view of a portion of the non-woven material during an initial stage in the manufacture thereof;

FIG. 2 is a sectional detail view taken along the plane of line 2--2 in FIG. 1;

FIG. 3 is a view, similar to FIG. 2, after the non-woven material of FIG. 2 has been compressed and bonded; and,

FIG. 4 is a perspective view of a pouch used in the invention.

With continuing reference to the accompanying drawing, wherein like reference numerals designate similar parts in the various views, reference numeral 10 generally designates a non-woven material formed of non-water sensitive fibers, such as those hydrophobic materials including polyester and polypropylene. The fibers 12 are of staple length and are arranged into a web of sheet construction using techniques, such as fiber carding, air laying, needle punching, felting or the like. The sheet thickness or interfiber spacing is adjusted so that the largest particles encountered in laundry detergent powder will pass through the material 10. The fibers comprising the sheet are then bonded together by chemical print bonding, heat pattern bonding, sheet saturation bonding or the like, so that the fibers 12 are flattened and compressed to fill the interstices, which bonding material, such as a conventional water-sensitive or soluble gum or adhesive, including casein, fill all remaining interstices. Thus, sufficient dry strength is achieved so that product integrity is attained during all stages of manufacturing of the pouch generally indicated at 20. In one embodiment the fibers are compressed such that the flattened fibers fill the interstices between the fibers. The fibers are then bonded with a bonding agent to hold the fibers in the flattened condition. The binding agent may be a water soluble binding agent or a frangible or weak binding agent which breaks by the mechanical action of the washing machine to allow the fibers to return to their natural uncompressed state so that the detergent particles can pass through the interstices.

The non-water sensitive fibers are selected from any of those fibers which, when wetted, do not lose their ability to hold their high to medium crimping and are selected from polyester, polypropylene or any combination or blends of the aforesaid fibers.

The web is compressed through compression rolls or belts so that the fiber spacings are reduced to such a degree that detergent powder of the smallest particle size to be encountered are effectively prevented from passing through the material 10. The sheet is then bonded in the compressed state with the water sensitive binder or a binder which can be mechanically disrupted.

When a pouch constructed of this material is wetter or subjected to agitation, respectively, the forces and binder holding the web in its compressed state are then eliminated in the laundering machine during the washing cycle allowing the material to expand to its original state, as in FIG. 1, thus permitting the enclosed detergent powder to be dispersed into the washing liquid.

Thus, no separate use of costly glues or adhesives for bonding the seams of the pouch 20 are required, the pouch being constructed by heat sealing, sonic welding, bonding or other simple means of manufacture.