US3076298A

US3076298A - Attachment of detergent material to synthetic sponge

Info

Publication number: US3076298A
Application number: US86965A
Authority: US
Inventors: Werner Otto Tundermann
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1961-02-03
Filing date: 1961-02-03
Publication date: 1963-02-05
Anticipated expiration: 1980-02-05
Also published as: FR1316036A; AU266114B2; DE1250043B; GB977156A; AU1359262A; BE613352A

Description

2 Sheets-Sheet 1 Feb. 5, 1963 w. o. TUNDERMANN ATTACHMENT OF' DETERGENT MATERIAL TO SYNTHETIC SPONGE Filed Feb. s, 1961 Feb 5, 1953 w.'o. TUNDERMANN v 3,075,298

ATTACHMENT OF DETERGENT MATERIAL TO SYNTHETIC SPCNGE Filed Feb. 3, 1961 2 Sheets-Sheet 2 INVENToR. WERNER OTTo TuNneRMANN Unitedl States Patent ilce 3,076,298 ATTACHMENT F DETERGENT MATERIAL T0 l SYNTHETIC SPONGE Werner Gtto 'linndermann,`y Colonia, NJ., assigner t IColgate-Palmolive Company, New York, N.Y., a corporation of Delaware Y Filed Feb. 3, 1961., Ser. No. 86,965

. 7 Claims. (Cl. 53-24) This invention relates to a method of strongly attaching a bar or cake of solid detergent to a synthetic sponge and relates also to sponges combined with detergent bars or cakes so elfectively that they are not separated during washing use, even when the detergent has been substantially completely consumed.

In the past, attempts have been made t-o combine soaps with Sponges.l In those effortsl directed to cementing sponge to the surface of the soap, it has been found that adhesion becomes unsatisfactory when the bar is wetted -and under ordinary washing conditions the soap and lsponge are soon separated. 'I'he present invention solves this. problem and provides an improved and practicable method, readily adapted to trouble-free automatic operation, for economically making the combined products. The novel products made -have been found to have the ability to adhere together during use, even when repeatedly subjected to solutions of alkaline detergent materials in warm water and the compressive, tensing and shearing forces accompanying washing actions.

In accordance with the present invention a process for attaching detergent material to synthetic sponge comprises applying to a bar or cake of solid detergent material selected from the group consisting of Water soluble soaps of higher fatty acids, water soluble synthetic organic detergents and mixtures thereof, a Water insoluble adhesive, a Water impermeable barrier, held to the detergent material by the adhesive, additional water insoluble adhesive and synthetic sponge, the additional adhesive holding the water impermeable barrier to the synthetic sponge, pressing the sponge against the detergent bar and maintaining it in position pressed against the bar, for a sufficiently long time to hold the water impermeable barrier tightly against the detergent with the adhesive covering and adhering to substantially all the contiguous Water impermeable barrier and detergent bar surface. Also in accord with this invention a combination synthetic sponge and detergent cake comprises a cake of detergent material selected from the group consisting of solid water soluble soaps of higher fatty acids, water soluble synthetic organic detergents and mixtures thereof, a water impermeable barrier held to the detergent by a Water insoluble adhesive and a synthetic sponge fastened to the water impermeable barrier.

rIFhe invention, its various objects and advantages will be apparent from the following description, taken in conjunction with the accompanying drawings in which:-

FlG. l is a schematic representation of a process for attaching detergent material to synthetic sponge;

FIG. 2 is a perspective view of an improved detergent bar of this invention;l

FlG. 3 is a vertical section taken along plane 3-3;

FIG. 4 is a perspective view of ano-ther detergent bar made in accordance with the present invention; and

FIG. 5 is a perspective view of an invented detergent bar, inverted for better illustration, after consumption of substantially all the detergent in normal handwashing usage.

In the embodiment of the invented process illustrated l bar form 11 in a vacuum soapplodder 13. Endless belt l5 supports the plodder bar to and from cutter 17 which 29. Die 27 has a projection 31 on the face thereof to f conveyed to an automatic machine 39 Vof the type frelquently employed for labeling bottles and jars, where the detergent cakes are indexed with assembled sponge- Y form a depression in a face of each of pressed detergent cakes 33, of size to match the Sponges and barrier films 37 to be inserted in the depressions and fastened firmly to the detergent. The pressed cakes 33 are then barrier units -41 and are fastened to them. A further are pre-indexed'sponge-barrierfunits. These are shown as rectangular Yflat-faced pieces of cross-sectional area equal to that of the detergent cake depression and covering a major proportion of a face of the cake. The spongebarrier combined units are formed by applying a barrier film to a strip of sponge with adhesives applied on both sides of the lm. In a preferred method a roll 43 or other continuous length of sponge in strip form 45 is unrolled and fed past a feeder 47 for adhesive and a doctor blade 49 to distribute the adhesive evenly in a layer of desired thickness. Next a strip 51 of lilm barrier of the same width as the sponge is unrolled from a reel and is brought into superimposition with the sponge. A pressure-sensitive adhesive is applied by feeder 53, and is doctored by blade 55 to correct thickness andcomplete coverage. A backing 57 of smooth paper or other suitable material is then joined to the combined sponge and barrier. It covers the pressure sensitive adhesive andV later acts to support and index the Sponges to be applied to detergent cakes, but it is readily stripped from the barrier film when desired, without tearing.

The continuous strip of cemented sponge, barrier and backing is fed to a cutter 59 which cuts through sponge and barrier lm, to shape them to t the depression molded in the detergent cake, but does not cut the paper backing 57. Stripper, 61, which may be associated with cutter 59, then removes the unwanted pieces of sponge and barrier and the strip of pre-cut Sponges is fed to the labeler 39. This machine strips the backing 57 from the Sponges and presses indexed Sponges against the detergent recesses, discharging the combination of sponge and detergent 63. the pressure sensitive adhesive holding them together sufliciently strongly to prevent detachment in the next operation.

The combination sponge-detergent is imediately sent to a wrapping station where an automatic machine 65 compresses the sponge, and holds it against the detergent face while a Wrapper 67 or. other confining packing is placed about it and fastened in place. Thus, the wrapper aids in improving the seal of the pressure sensitive adhesive between sponge and detergent and the resilient sponge holds the wrapper taut to improve its appearance. After wrapping, the wrapped cakes are packed in cases, preferably by an automatic packing machine, represented by numeral 69. The cases are so dimensioned that they, too, act to compress the sponges against the detergent cakes and thereby hold the pressure sensitive adhesive in close'relationship with detergent and barrier film so as to maintain and even improve the seal between them during storage.

Although the described procedure and apparatuses lend themselves to accurately fitting the synthetic sponge in the depression 75, it is sometimes advantageous to allow Ya tolerance or clearance between the sides of the sponge and the sides of the depression to facilitate placement of the Patented Feb. E., '3133 sponge without, accidentally impinging the barrier (and its adhesive coating) against the raised face of the detergent cake. After placement of the sponge the presence of the clearance space is disadvantageous because it interrupts the continuity of the cake surface, making it less attractive and also allowing water to more readily penetrate to the edge of the interface between detergent and pressure sensitive adhesive. In FIG. l a second press 73 is shown `before the wrapping machine to press the sponge tightly against the detergent cake and to deform the detergent enough to close the clearance between sponge and detergent. In this press designs may bev pressed into detergent and sponge and with suitable modifcation, decorative, identifying or advertising material may be printed on the sponge, although pre-printed Sponges may also find use.

The novel product of the process described is illustrated in greater detail in FIGS. 2 and 3. A cake of deter, gent 33 contains a depression 75 into which is cemented a synthetic sponge 35 cemented to a barrier iilm 37. The product of FIG. 4 is similar but can be made without pressing operations, the plodded detergent bar being extruded in the. shape illustrated, preassembled sponge, barrier and pressure sensitive adhesive strip being cemented in place and the strips being cut to length and packed. The primed numerals identify elements corresponding tothose numerals in FIGS. 2 and 3. In FIG. 5 a thin sliver 77 of soap is shown still adherent to thin plastic barrier film 37 which is still held to sponge 35. The sliver 77 is all that is left ofl a cake of FIGS. 2 and 3 after normal handwashing or bath use. By intentionaly flexing the sponge and barrier and applying force, the barrier can be separated from the sponge, if so desired, but in normal careful use they will remain attached. After consumption of the detergent the pressure sensitive adhesive coated barrier will remain clean looking and will not pick up dirt, when wet. It will serve to hold the spongey together and will help to prevent its disintegration during use. Still, the adhesive will allow the sponge to be easily adhered to dry surfaces, such as walls or sinks.

The sponge which may be combined with the detergent cake is substantially water insoluble and resilient. It is preferably very light in weight, much less than the density of water, and contains an interconnected cellular network the cells being filled with gas, usually air. With this structure the sponge is able to take up moisture throughout its body, when it is collapsed by pressure, expelling the air, and then released, allowing replacing of the air by wash water. Such continuous compression and expansion of the sponge face facilitates the mixing of air and detergent solution in films and promotes the development of a copious foam. The small interconnecting cells of the sponge are substantially uniform in size to the eye and generally range from 0.005 to 0.100 inch. The material of which the sponge is made should be dimensionally stable and little affected by the presence of moist or dry conditions, insofar as expansion and contraction are concerned. Suc-h a sponge will not tend to warp or distort during use due to alternate moistening and drying of the detergent cake and Will not tend to pull away from the surface of the detergent. It is also desirable for the mate rial of the sponge, itself, to be relatively non-absorbent, to promote faster draining and more rapid drying of the product. Among suitable sponge materials are the various synthetic products, especially those based on substances commonly referred to as plastics. Natural animal sponges do not have the properties or structure tol be suitable in the invented combination article. Ordinarily cellulose Sponges may not vbe used because their dimensional' instability and capillary action make them less suitable than other synthetics. In the group of satisfactory materials which may be made into Sponges useful in this invention there may be mentioned those made by foaming rubber, either natural or synthetic, as Well as Sponges Vmade by foaming resilient plastics such as poly-ethylene, poly-esters,

polyvinyl chlorides and acetates and other compounds of similar properties. The most satisfactory of these plastic Sponges found to date are those made from polyurethane, preferably of the polyester type for harder and medium Sponges and of the polyether type for those desired to be softer. These Sponges are of good color, high resiliency, low water absorption and possess surfaces which in ordinary usage contribute an excellent massaging action on the skin without irritation. These polyurethane Sponges do not lose their desirable tactile properties when wet. As with most plastics the polyurethanes are available in a Wide variety of colors which contribute toward the esthetically pleasing appearance of the combination soap and sponge. In the molding or trimming process the polyurethane sponge may be shaped to include a trade name or decoration which, unlike the case with soap alone, will not be removed as the product is consumed. If desired, the Sponges may be printed instead.

The detergent material which is a part of the invented article of manufacture is an organic detergent which may be selected from the group consisting of higher fatty acid soaps and water soluble synthetic organic detergents. Mixtures of soaps, mixed synthetic organic detergents and soap-synthetic organic detergent combinations may be employed. These materials are water soluble and normally solid so that they are suitable for manufacture in bar and cake form.

Among the synthetic organic detergents it is preferred to utilize those which are anionic or non-ionic. As suitable anionics there may be mentioned the fatty alcohol sulfates, fatty acid monoglyccride sulfates, sulfated oxyethylated fatty alcohols, alkyl aryl sulfonates, alkyl sulfonates, higher fatty esters of isethionic acid, higher fatty amides of taurine and N-methyl taurine, higher fatty amides of sarcosine, higher fatty sulfo-acetates and sulfated higher fatty alkylolamides. The higher alkyl and acyl groups mentioned in the above description are those containing 8 -to 20 carbon atoms, preferably l2 to 18 carbon atoms. Usually it is preferred that the carbon atoms of the acyl and alkyl groups should be in straight line configuration but often, `as in the case of the alkyl benzene sulfonates, branch chain groups may be employed in limited minor amounts. All the anionic synthetic organic detergents are used as water soluble salts, preferable as alkali metal salts. Alkaline earth metal salts, ammonium salts, triethanolamine salts and others may also be used but the salts of sodium and potassium, especially the former, are preferred because they usually possess better water solubility and are of suicient hardness to be made into a cake product.

The higher fatty acid soaps are those which are Water soluble and normally solid. Such soaps are usually of 8 to 20 carbon atoms and are obtained by saponication of the usual soap making oils such as coconut oil, tallow, hydrogenated coconut oil and tallow, lard, grease, babassu oil, palm oil, palm kernel oil and other well-know materials of similar types. The soaps are usually made in the forms of their sodium salts although other alkali metal salts such as those of potassium may also be found to be satisfactory. Triethanolamine soaps or soaps of other organic bases can be used but are not usually as efficient .as those of sodium. The alkaline earth metal soaps and the magnesium soaps are not included within the scope of water soluble higher fatty acid soaps, although these materials may be added to the bar cornpositio-n as fillers or for other purposes.

Normally solid water soluble non-ionic detergents are those which usually contain chains of lower alkylene oxide to increase their hydrophilic properties. Included in this group are the higher fatty acid esters of polyoxyethylene alcohols ethylene oxide-propylene oxide block copolymers of higher molecular weight, eg., 5,000 to 20,000, ethylene oxide adducts of lower di-alkyl phenols, other polyalkoxylated lipophilic stems and higher fatty esters` of multi-hydroxy compounds such as sugars, polyglycols and so forth.

permeable, thin flexible and resilient films.

'substantially impermeable to liquid water.

Between detergent and sponge is a barrier, usually in thin film form. This barrier should be thin enough to be resilient and flexible so that it will not easily be pried loose from the detergent and sponge to which it is fastened. `The barriers that have been found to be most use- .ful are those made from synthetic organic plastics, usually in thickness of from 0.25 to 5 mils, preferably about 1 mil. Y

The plastics used 'are impermeable or substantially impermeable tewater and prevent transmission of moisture through to the adhesive bonding detergent and barrier, thus preventing or inhibiting the weakening laction of wash water on such adhesive. Although some wash water may contact the edges of adhesive layer under the barrier, this will not usually sufficiently weaken the bond to causethe separation of barrier fil-m from detergent. It has been found that layers of water insoluble adhesives alone will not perform the function of a thin continuous plastic film, apparently because the adhesives, even though carefully applied, do contain perforations through which water may penetrate to loosen the detergent- `barrier bond. This Afault is accentuated when thin adhesive layers are used. Although sheet plastics also sometimes contain minute openings, usually these are few enough and small enough so that very thin films are substantially impermeable to Water.

Among the useful barrier fil-ms, the most preferred is poly (ethylene terephthalate), known as Mylar. Other polyesters, such as those of alpha,omegaglycols and symmetrical aromatic dicarboxylic acids; vinylidene chloride-vinyl chloride vcopolymers (Saran); polymeric aniides, such as the polymers of hex-amethylene diamine and adipic or sebacic acid (Nylon 66 and Nylon 610); plasticized polyvinyl chloride (Tygon, Geon); rubbers, both natural and synthetic, such as neoprene, butyl rubber, rubber hydrochloride, polyisop-rene, and GR-S are also useful, being capable of being made as water im- These materials usually should have water absorbing capacities of less than 3% and preferably less than 0.5% as measured by ASTM test D 570. Such plastics are considered to be Cellulosic plastics, such as cellulose acetate and acetate-butylate have rather high moisture absorption and transmission rates and are less flexible than the other plastics listed but Vmay be useful in certain applications. The waxy plas-` tics, such as polyethylene and-polypropylene are good barriers, having moisture absorptions of about 0.01% or less but are more difficult to fasten firmly to soap and sponge than the plastics listed above. Other barrier film materials than the plastics, e.g., aluminum foil, prevent moisture penetration and can be cemented but they are relatively unyielding in washing, causing some skin irritationduring use, and are easily creased or marked in handling.

The water insoluble adhesive employed to hold the bers such as polyisobutylene, polyisoprene, neoprene' GR-S and thiokol can also be used. Often, combinations of rubbers and resins are employed, e.g., nitrile rubber and phenolic resin. Instead of rubbers, other elastomeric or liexible cements may be used, including silicone elastomers, polyethylenes, polyvinyl acetate, polyvinyl butyral, pressure-sensitive adhesives and vinyl nbutyl others,` to mentiono-nlyna few. Even the harder plastics may'bepused, such as the epoxy resins, protein based waterminsoluble g lues,.melamine formaldehyde, the:

rough surface is esthctically undesirable.

the nature of the synthetic sponge and the barrier used and should usually be selected for the greatest degree of adhesion under the conditions of use. Also, if the detergent is of alkaline reaction, eg., soap, the cement should be resistant thereto so that it is not hydrolyzed or otherwise adversely affected in use. Nitrile rubber, epoxy resin and polyisobutylene adhesive on the invented products retain their adhesive, powers, even in strong soap solutions.

Although it is usually preferred to employ an adhesive, the sponge and barrier film may be sealed together by othermeans, too. Thus, fusion or heat sealing is sometimes applicable. The sponge may have its surface fused or molded to form a continuous film or skin on the surface to be joined to the detergent. Even staples or other holding devices could be used if unobtrusive and unobjectionable in use and if the barrier was resealed or otherwise kept water impermeable.

While the fastening of barrier film to sponge may be eected by various means and the selection of an adhesive is not extremely critical, the problem of sealing a material to a detergent is more difficult of solution. Itl has been found, after extensive experimentation that many water insoluble adhesives that are capable of adhering to dry soap and other detergent materials are easily removed when the detergent becomes wet or moist. The provision of a barrier between sponge and soap mitigates this adverse effect but it is still highly preferable to employ certain types of adhesives for best adherences. It has been found that the non-resilient 4and inflexible adhesives, such as epoxy resins, phenol and formaldehyde derivatives, proteinaceous gluesv and so forth leave an objectionablehard, sometimes crystal-like deposit on the barrier after the detergent has been consumed. This The coating of rigid cement also stiffens the barrier, decreasing its flexibility and its ability to distort slightly when stressed, rather than to be torn away from the detergent. This loss of exibility causes the sponge to part from the soap before the soap is substantially consumed,-decreasing the kutility of the product. `the flexibel and resilient adhesives, such as those com- It is therefore desirable to employ monly referred to as being pressure-sensitive. These remain resilient almost permanently and adhere to the soap or detergent, even when repeatedly immersed in water. If'loosened, the pressure sensitive adhesives can be rejoined to the detergent when dry by slight manual pressure. In this respect it is noted that v:for best adhesion the bar should be hard and dry to the touch when the sponge-barrier is rst put in place. vcontent of such a bar will be 5-20%.

equal in thickness to the Mylar films described earlier, is-

coated with non-adherent backer and may be stored until needed for application to the detergent, such application preferably being effected by an automatic device, such as the Tuck Labeler made by Technical Tape Corporation, New Rochelle, N.Y. v

Like other pressure sensitive adhesives those based substantially on polyisobutylene are usually composed of a plasticized high molecular weight elastomer, the plasticizer in this casebeing a low molecular weight fraction t of the same material, polyisobutylene.

Other elastomers such as the rubbers andorganic polymers described earlier may also be plastieized to form pressure sensitive products, according to known methods. Usually the plasticizer used will be a suitable hard resin dissolved in an oil, the resin and oil producing a tackiness and the resin generating adhesive strength. Still other types of pressure sensitive adhesives are known and may be ernployed, eg., those based on a polyester of castor oil and maleic ester.

In applying the pressure sensitive adhesive to the barrier film before sealing to the detergent care should be taken that it covers all the film, so as not to leave any portions thereof uncemented. This decreases the chance of moisture loosening the adhesion of sponge to detergent. Furthermore, the pressure exerted in fastening the sponge to the detergent should be enough to press all the pressure sensitive adhesive into contact with the detergent surface.

As was said previously, the sponge units, less detergent, may first be assembled, then stored and applied to detergent when desired, either as individual pieces or as a length which is subsequently cut with the detergent bar, as by a machine like that represented by numeral 17. Thus the manufacturing processes are simplified and made more flexible and may lbe carried out using presently available equipment to a substantial extent.

Together with the processing advantages of the invention there are also obtained very important product advantages. The improved adhesion of detergent and sponge attributable to the present invention has been discussed at length and is of vital importance in the production of an acceptable, as well as economical article. This enables the user to obtain the full benefit of the combination article for a greater period, in effect, increases the useful life of the product. Some of these benefits are outlined here.

The synthetic sponge, being lighter than water, increases the buoyancy of the product and causes even milled soaps and detergents to float. The sponge furnishes a convenient rest for the detergent, facilitating drainage and decreasing smearing or sloughing of detergent gel. This is especially important in the cases of synthetic detergent bars and soapsynthetic detergent bars, which are usually more soluble than desirable. TheV sponge rest also increases the sliding friction of detergent, preventing slipping off inclined washstand surfaces and giving the user a better grip. The sponge aids in producing a copious lather and acts as a wash cloth, helping to clean the skin. Because the `surface properties of the sponges can be readily regulated in production, firm or soft washing surfaces can be made, as desired. The sponges can be molded, pressed cut or `printed with permanent decorative material, advertising, trade names or instructions for use. Finally, all these additional advantages over ordinary soaps are attainable with only a small increase in production costs, if the products are made by the claimed processes. In some instances, where pressing is omitted (being now unnecessary because the sponge may be preprinted with trade name and decoration) the cost of the sponge bar may be even less than the cost of an equivalent sized detergent bar.

The above invention has been described with respect to illustrations of preferred embodiments thereof. It is not limited to such methods and articles only, the scope of the invention being as recited in the claims.

What is claimed is:

l. A process for attaching detergent material to synthetic sponge which comprises applying to a bar or cake of solid detergent material selected from the group consisting of water soluble soaps of higher fatty acids, water soluble synthetic organic detergents and mixtures thereof, a water insoluble adhesive, a water impermeable barrier, held to the detergent material by the adhesive, additional Water insoluble adhesive and synthetic sponge, the additional adhesive holding the water impermeable barrier to the synthetic sponge, pressing the sponge against the detergent bar and maintaining it in position pressed against the bar, for a sufficiently long time to hold the water impermeable barrier tightly against the detergent with the adhesive covering and adhering to substantially all the contiguous Water impermeable barrier and detergent bar surface, so that, during washing, water will not be able to contact the detergent under the sponge and will not be able to contact the adhesive holding detergent to impermeable barrier, except around the peripheral portions thereof.

2. A process according to claim l in which the synthetic sponge, water insoluble adhesives and Water impermeable film are applied to the solid detergent material together.

3. A process for attaching detergent material to synthetic sponge which comprises pressing against a bar or cake of solid detergent material selected from the group consisting of Water soluble synthetic organic detergents and mixtures thereof, a synthetic sponge having fastened to it with water insoluble adhesive one side of a water impermeable film which is coated on the other side with a resilient, water insoluble, pressure sensitive adhesive, so that the pressure sensitive adhesive holds the film to the detergent, applying to the combined detergent bar and sponge a restricting cover while holding the sponge against the detergent, which cover will hold the sponge against the detergent for a sufficiently long time to hold the pressure sensitive adhesive covering and adhering to substantially all the contigious water impermeable film and detergent bar surfaces so that, during washing, water will not be able to contact the detergent under the film and will not be able to contact the adhesive holding the detergent to the film except around peripheral portions thereof.

4. A process according to claim 3 in which the detergent is pressed to shape suitable for fastening to a synthetic sponge, a plurality of Sponges, including a plurality of film coatings therefor, cemented on one side to the sponge and on the other side covered with a pressure sensitive adhesive, are serially held to a strip of backing material, the pressed detergent cakes and strip of Sponges are fed together to a joining station, the backing is stripped from the Sponges and they are consecutively indexed with the detergent bars, pressure sensitive adhesive facing the bars, are pressed against the detergent bars and the detergent bars with Sponges attached are wrapped.

5. A process according to claim 4 in which the detergent bar contains a soap of higher fatty acid, the adhesives are alkali resistant, the detergent bar is plodded and pressed at a moisture content of 5 to 20% and temperature from -140 F. to cake form having a cavity for insertion of a sponge, the sponge with pressure sensitive adhesive on the attached film is placed in the cavity and pressed against the detergent cake and the cake with sponge attached is re-pressed to force detergent at the cavity edges against the sides of the sponge.

6. A process for attaching detergent material to synthetic sponge which comprises plodding a continuous bar of solid detergent material selected from the group consisting of water soluble soaps of higher fatty acids, water soluble synthetic detergents and mixtures thereof, applying to the continuous bar of detergent a water insoluble adhesive, a water impermeable barrier, held to the detergent by the adhesive, a synthetic sponge and means for holding the sponge to the barrier, pressing the sponge, barrier and adhesive against the detergent bar to hold the barrier against the detergent with the adhesive covering and adhering to substantially all the contiguous barrier and detergent bar surface and then cutting the bar of detergent material and attaching sponge and barrier to lengths.

7. A process according to claim 6 in which the synthetic sponge and attached water impermeable barrier coated with water impermeable pressure sensitive adhesive are pre-assembled and subsequently applied to the solid detergent material together before being cut to length.

References Cited in the file of this patent UNITED STATES PATENTS 717,256 Nilsson Dec. 30, 1902 2,365,920 Vaughn Dec. 26, 1944 2,420,734 Churchill May 20, 1947 2,731,777 Wollersheim Jan. 24, 1956

Claims

1. A PROCESS FOR ATTACHING DETERGENT MATERIAL TO SYNTHETIC SPONGE WHICH COMPRISES APPLYING TO A BAR OR CAKE OF SOLID DETERGENT MATERIAL SELECTED FROM THE GROUP CONSISTING OF WATER SOLUBLE SOAPS OF HIGHER FATTY ACIDS, WATER SOLUBLE SYNTHETIC ORGANIC DETERGENTS AND MIXTURES THEREOF, A WATER INSOLUBLE ADHESIVE, A WATER IMPERMEABLE BARRIER, HELD TO THE DETERGENT MATERIAL BY THE ADHESIVE, ADDITIONAL WATER INSOLUBLE ADHESIVE AND SYNTHETIC SPONGE, THE ADDITIONAL ADHESIVE HOLDING THE WATER IMPERMEABLE BARRIER TO THE SYNTHETIC SPONGE, PRESSING THE SPONGE AGAINST THE DETERGENT BAR AND MAINTAINING IT IN POSITION PRESSED AGAINST THE BAR, FOR A SUFFICIENTLY LONG TIME TO HOLD THE WATER IMPERMEABLE BARRIER TIGHTLY AGAINST THE DETERGENT WITH THE ADHESIVE