US3634183A

US3634183A - Compacted regenerated cellulose sponges and method of preparing the same

Info

Publication number: US3634183A
Application number: US37736A
Authority: US
Inventors: Leonard J Viola; Eugene H Gans
Original assignee: Richardson Merrell Inc
Current assignee: Richardson Vicks Inc
Priority date: 1970-05-15
Filing date: 1970-05-15
Publication date: 1972-01-11
Anticipated expiration: 1989-01-11

Abstract

Stacks of individual thinly sliced sheets of regenerated cellulose may be compressed at pressures of 2,000-20,000 pounds per square inch to reduce the thickness thereof to 8-20 percent of the original stacked height to obtain a product which remains compressed and in which the individual thin sheets of regenerated cellulose adhere to each other so long as they are dry. The compressed sheets can be cut into desired shapes, packed in shipping boxes, transported and handled on automatic filling machines without falling apart. The individual units are useful in preparing cosmetic pads for cleaning, disinfecting and otherwise applying liquid medicaments to the skin.

Description

llnited States Patent [72] lnventors LeonardJ. Viola [54] COMPACTED REGENERATED CELLULOSE SPONGES AND METHOD OF PREPARING THE SAME 6 Claims, 6 Drawing Figs.

[52] U.S.Cl 161/159, 156/306, 161/269 [51] Int. Cl B32b 3/26, C09 5/00 [50] Field ofSearch 161/159,

[56] References Cited UNITED STATES PATENTS 2,133,805 10/1938 Brown 161/159 2,744,292 5/1956 Schlosser et al. 161/269 Primary Examiner--William .1. Van Balen Attorneys-Harvey W. Edelblute and George W. Rauchfuss,

ABSTRACT: Stacks of individual thinly sliced sheets of regenerated cellulose may be compressed at pressures of 2,00020,000 pounds per square inch to reduce the thickness thereof to 8-20 percent of the original stacked height to obtain a product which remains compressed and in which the individual thin sheets of regenerated cellulose adhere to each other so long as they are dry. The compressed sheets can be cut into desired shapes, packed in shipping boxes, transported and handled on automatic filling machines without falling apart. The individual units are useful in preparing cosmetic pads for cleaning, disinfecting and otherwise applying liquid medicaments to the skin.

PATENIEDJAHI I 1972v 3534 1 3 HEIGHT IN mcucs '6 8 8 8 5' y- PRESSURE EUGENE ll. 6 I3 7 KTTORNEY COMPACTED REGENERATED CELLULOSE SPONCES AND METHOD OF PREPARING THE SAME This invention relates to a new and useful article of manufacture. More particularly, the invention relates to a multiplicity of individual thin sheets of dry, regenerated cellulose pressed together in compact units which are better adapted for handling, shipping and packaging by automatic machinery.

I-leretofore, medicated or cosmetic cleansing solutions have been applied to the skin with cotton pads and similar devices. Cotton pads have the disadvantage that they are not rigid, and do not retain their shape, and tend to roll up with use and leave a lint residue on the skin. Also, they are not as effective cleansing agents as the sponges to be described hereinafter since they do not hold as much liquid, do not have the same effective and desirable scrubbing action, and do not hold as much dirt and skin oil as do the products of the present invention.

The new articles of manufacture of the present invention are particularly useful in manufacturing cosmetic aids for applying cleaning, disinfecting, astringent, deodorant and other liquid preparations to the skin. The eventual product for which the new articles of the present invention are used comprises a liquidtight package containing a plurality of thin wafers of regenerated cellulose, saturated with a solution having a cleaning or other desired cosmetic properties as indicated above. Such a package might, for instance, contain up to 50 individual sponges of regenerated cellulose of l to 4 square inches in area, and from about one sixty-fourth to onefourth inch in thickness. The individual sponges are used by simply opening the container and removing one of the liquid saturated layers from the container, rescaling the package to prevent evaporation of the liquid, and rubbing the wet sponge on the skin.

It has been found that it is difficult to handle dry thinly cut sponges of regenerated cellulose in ordinary manufacturing processes. The thin sponges are very bulky and occupy an unnecessarily large amount of space after they are cut and when they are to be shipped to the place where they are to be used in manufacturing cosmetic aids. They are, individually, extremely light in weight and will not stack easily and will not remain stacked when assembled. A very slight movement, such as a gust of air, may blow them about and they have to handled very carefully so that a predetermined number of sponges may be placed in each container. They do not lend themselves to handling with automatic filling machines. The present invention provides a method of preparing sponges in a unitary form which can be placed in shipping containers of relatively small size, which can be shipped economically and filled with automatic equipment into containers such as jars on an assembly line where the finished cosmetic product is made.

In accordance with the present invention a block of regenerated cellulose sponge material, for example a 20-inch cube, is sliced into thin sections one sixty-fourth inch to onefourth inch thick and these slices are stacked into a pile. The number of thin sheets in each pile is dependent upon the number of sponges that is desired per package of product, for instance, to 50 individual slices. The dry stacked sponges are then compressed with a hydraulic press. In a preferred example, 36 thin sheets of cellulose sponge having an individual nonnal dry thickness of 0.060 inches were stacked to provide a pile 2% inches high. When this pile was placed in a hydraulic press and pressure applied, it was found that at a total pressure of 7,000 pounds per square inch the height of the pile of square sponges had been reduced to about 0.160 inches.

FIG. 1 of the accompanying drawings is a graph showing the compression of such a pile of sliced sponges as the pressure is increased.

The present invention is based upon the surprising discovery that when thinly sliced cellulose sponges as described herein are strongly compressed, they are compacted and adhere together as a unitary mass. The resulting relatively dense, coherent slab can be sawed with a band saw, or other appropriate cutting device, into square or other shapes of desired size and each resulting unit remains compressed as a coherent unitary mass with the individual sponges sticking together so that they can be packed in a relatively small container, shipped to a factory and placed with automatic equip ment into glass jars on a production line.

FIG. 2 of the drawing is a perspective view of an individual thinly sliced sponge of the present invention 10 as it would normally appear without having been compressed.

FIG. 3 of the drawing is an elevational view illustrating a stack of uncompressed cellulose sponges 11 between the platens, 12 and 13, of a hydraulic press.

FIG. 4 of the drawing is an elevational view showing the compressed sponges after pressure is applied.

FIG. 5 of the drawing is an elevational view of a unit of compressed sponges, l4, placed in a jar, 15. A lower section of the jar is cut away to show the compressed sponges in the jar.

FIG. 6 is an elevation of the same jar of FIG. 5 with the top portion cut away showing the expanded sponges after being saturated with antiseptic cleaning liquid.

As will be apparent, the sponges may be cut into squares, rectangles, circles, ovals or other desirable shapes. Obviously, when the material is cut in squares there is less waste of cellulose material. In FIG. 2, the corners of the sponge are shown to have been rounded slightly so that a circular jar will hold larger sponges.

The compressed sponge wafers adhere surprisingly well to each other. In the following table there is shown the force that is required to separate individual sponges from a compressed block of 38 of the same. The individual dry sponges were 1% inches by 1% inches by 1/16 inch before being compressed with the total pressure in pounds per square inch as shown in the following table.

As will be seen, when the dry sponges were compressed with a total pressure of 8,000 pounds, it took 200 grams of force to separate one of the sponges of the compressed group from the others. At 20,000 pounds total pressure a weight of 370 grams was required to separate the sponges. Accordingly, a plurality of dry sponges sliced to a thickness of one sixty-fourth of an inch may be pressed together at pressures of about 2,000 pounds per square inch to 20,000 pounds per square inch to obtained compressed units which may be handled with ordinary care in packaging and filling operations without danger of having the sponges fall apart and thus made unsatisfactory for automatic filling operations.

It is surprising that the thinly sliced dried sponges remain compressed and adhere to each other when subjected to the pressing operation just described. Thinly sliced sponges of other material, polyurethane foam sponges for example, immediately return to their original thickness when a pile of them is compressed and the pressure released. Furthermore, they dont stick together. On the other hand, the thinly sliced sponges of regenerated cellulose of the present invention remain compacted and stick together. This is probably due to the relatively low degree of resiliency of the cellulose sponge material and the fact that, when the sponge is cut, the surface is rough due to the ragged edges of the pores and protruding fibers which are a part of the sponge composition. These ragged edges and protruding fibers tend to intertwine and hold the sponge slices together. However, when an aqueous antiseptic cleaning solution is added to the compressed sponges they immediately absorb the liquid and expand to slightly more than their original dimensions.

As noted above, one of the important advantages of the present invention is that the sponges will hold a relatively large amount of the medicated cosmetic solution. In fact, the amount of aqueous liquid soaked up by the compressed sponges amounts to over times their weight. Accordingly, when an antiseptic cleaning solution is poured into a suitable container having compressed sponges therein, as shown in FIG. 5, the sponges will immediately absorb the liquid and return to at least their original precompressed volume and shape as shown in FIG. 7. The sponge pads no longer adhere to each other and are easily separated from one another when it is desired that one be removed from the jar and used to clean the skin.

The basic cellulose sponge material from which the thin sponges of the present invention are cut is prepared in conventional manner. In the manufacture of cellulose sponges, the base starting material is generally bleached alpha-cellulose, although other cellulosic materials can also be used. Sheets of alpha-cellulose from wood fibers, such as a 12 inch X l2 inch square about three-eighths inch thick, may be used. These sheets are steeped in a concentrated sodium hydroxide solution (usually 50 percent) to produce sodium cellulose.

After the cellulose has been thoroughly soaked at room temperature, the sodium cellulose is removed from the NaOH solution and placed in a sealed tank and treated with carbon disulfide to obtain a viscous orange gel known as cellulose xanthate, or viscose. The viscose is pumped into a blender where fibers, such as hemp, nylon, wood fiber or cotton, in amounts of 1 to 10 percent by weight are added to strengthen the sponge. Then salt crystals, such as Glaubers salt, are added to form the holes of the final sponge. The mixture is then placed in a mold ofa desired size, such as inches by 20 inches, and the mold is placed in a dilute bath of sulfuric acid. The dilute acid solution enters the mold through various cutouts" in the mold and breaks down the cellulose xanthate to regenerate the cellulose. Also, the Glaubers salt is dissolved, thus forming the pores in the sponge.

The block of sponge is then washed thoroughly with tap water to remove the carbon disulfide and Glaubers salt. Plasticizer, dissolved in water, if used, is then added by running it through the sponge block. The sponge block is then dried in an oven.

By the term dry" when used in connection with the cellulose sponge material that is compressed, we mean that the sponges are dry to the touch as would be the case when they have established equilibrium with the ambient atmosphere. Regenerated cellulose sponge material containing up to 12 percent by weight of moisture can be used in preparing the new products of the present invention. If the moisture content of the cellulose sponge is too high, the sponges may not stick together as described above.

Although a preferred method of compacting thin cellulose sponges is as described above in which sheets of previously sliced dry regenerated cellulose sponge material about 20 inches square and one sixty-fourth inch to one-fourth inch in thickness are compressed at 2,00020,000 pounds per square inch, the new article of the present invention may also be made by preparing bars of regenerated cellulose sponge material of any desired length and having any desired crosssectional configuration, for example 1% inches by 1% inches, and slicing these bars in any convenient manner to the desired thickness. A selected number of such thinly sliced wafers, for example l0 to 50, are carefully removed from the slicing machine and while still in a stacked unit are compressed with the desired pressures to obtain a unit of about 8 to 20 percent of the original thickness of the stacked uncompressed sponges. The density of the compressed sponge unit will depend upon the pressure applied as well as that of the original sponge. However, as uncompressed sponges have a density of about 2 to 8 grams per cubic centimeter, the com ressed unit will have a density of about 10 to I00 grams per l0 cubic Active Ingredients Percent w/v Salicylic Acid 025 Hexachlorophene 0.10 Allantoin 0J0 Carboxycycloimidutc 1.00

These active ingredients are dissolved in 35 to 40 percent alcohol solutions and a pleasant fragrance as desired is added. In the above formula, salicylic acid is a well-known keratolytic agent often used in cosmetic and cleaning preparations to promote the healing of acne lesions. Hexachlorophene has been extensively used as an antibacterial agent in acne products, surgical scrubs and toilet soaps. It is substantive to the skin and nonirritating. Allantoin is widely used in topical preparations to promote healing and stimulate the growth of healthy tissue. Carboxycycloimidate is a nonirritating surfactant with excellent cleaning properties. The alcohol in the product produces a subjective feeling of activity and aids in the cleaning abilities of the product.

It will be understood, of course, that the dried compressed sponges of the present invention can be saturated with aqueous solutions which will not of themselves be antiseptic or have cleansing properties. For example, the sponges may be saturated solutions having cleansing, astringent, antiseptic as well as medicinal and cosmetic properties of various kinds. The particular nature of the solution is immaterial insofar as the novel compressed sponges is concerned.

What is claimed is:

1. An article of manufacture comprising a dry coherent unitary body comprising a plurality of thin slices of regenerated cellulose sponge material, the said units being compressed to a thickness of 8 to 20 percent of their normal dry thickness and the individual slices thereof adhering to each other while in the dry state.

2. An article of manufacture in accordance with claim 1 in which the individual slices of regenerated cellulose have a compressed thickness of 8 to 20 percent of 1/64 inch to A inch.

3. An article of manufacture in accordance with claim 2 in which the compressed slices have an area of between I and 4 square inches.

4. An article of manufacture in accordance with claim 3 in which the compressed cellulose sponge unit comprises five to 50 individual thin slices of regenerated cellulose.

5. A method of preparing the article of manufacture of claim 1 which comprises subjecting stacks of 10 to 50 sheets of regenerated cellulose sponge material, each sheet having a dry thickness of H64 inch to /1 inch to a pressure within the range of 2,000 to 20,000 pounds per square inch whereby the sheets are compressed to within 8 to 20 percent of their original thickness.

6. A method in accordance with claim 5 in which the compressed sheets are cut into units having an area of l to 4 square inches.

Claims

2. An article of manufacture in accordance with claim 1 in which the individual slices of regenerated cellulose have a compressed thickness of 8 to 20 percent of 1/64 inch to 1/4 inch.
3. An article of manufacture in accordance with claim 2 in which the compressed slices have an area of between 1 and 4 square inches.
4. An article of manufacture in accordance with claim 3 in which the compressed cellulose sponge unit comprises five to 50 individual thin slices of regenerated cellulose.
5. A method of preparing the article of manufacture of claim 1 which comprises subjecting stacks of 10 to 50 sheets of regenerated cellulose sponge material, each sheet having a dry thickness of 1/64 inch to 1/4 inch to a pressure within the range of 2,000 to 20,000 pounds per square inch whereby the sheets are compressed to within 8 to 20 percent of their original thickness.
6. A method in accordance with claim 5 in which the compressed sheets are cut into units having an area of 1 to 4 square inches.