CA1325560C

CA1325560C - Wet wipes

Info

Publication number: CA1325560C
Application number: CA000613238A
Authority: CA
Inventors: Ho-Ward Julie Yoh
Original assignee: Scott Paper Co
Current assignee: Procter and Gamble Co
Priority date: 1988-10-18
Filing date: 1989-09-26
Publication date: 1993-12-28
Anticipated expiration: 2010-12-28
Also published as: JPH02157217A; DE68919991T2; ES2065392T3; KR0139215B1; JP2557987B2; NO894131D0; DK514589D0; EP0365160B1; US4904524A; EP0365160A2; AU612100B2; EP0365160A3; AU4177789A; NO894131L; HK103995A; KR900005920A; NO173764B; DK514589A; DE68919991D1; NO173764C

Abstract

ABSTRACT OF THE DISCLOSURE
A wet wipe comprising a porous sheet impregnated with an aqueous lotion and, concentrated near the surface of the sheet, polymeric beads containing a functional ingredient which is useful for treating the human skin or environmental surfaces and which are characterized in providing controlled release of the functional ingredient, and methods of making said wet wipe.

Description

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WET W I PES

BACKGROUND OF THE INVENTION
Field of_the I nvention The present invention relates to a wet wipe comprising a porous sheet impregnated with an aqueous lotion and further including polymeric beads which are characterized in providing controlled release of a functional ingredient.
Description of Related Art A variety of treated cloths which are adapted for skin care are commercially available. Such products typically comprise paper or non-woven fabric sheets which are wetted with a aqueous solution of water soluble or water dispersible ingredients. The difficulty presented by these ingredients is that they are typically water insoluble or hydrophobic. It is well-known to incorporate -hydrophobic cosmetic in~redients in the form of an oil-in-water -emulsion. Se~ U.S. Patent 4,559,157, granted December 17, 1985 to mith et al, "Cosmetic Applicator Useful for Skin Moisturizing".
The drawback of the oil-in-water emulsion approach is twofold.
One is that these emulsions tend to be unstable; secondly, the chemicals which emulsify the hydrophobic materials also tend to keep such components from uniformly adheriny to the human skin.
Accordingly, it is an object of an aspect of the present invention to provide hydrophobic functional ingredients in a wet wipe in a stable form. ~ -It is an object of an aspect of the present invention to controllably release such functional ingredients when applied to the human skin or environ~ ;
mental surfaces.
Other objects advantages and novel features of , the present invention will be apparent to those skilled in the art from the following description and appended clalms .
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132~60 SUMMARY OF THE INVENTION
Variou~ aspects of the invention are as follows:
A porous sheet impregnated with an aqueous lotion comprising a hydrophobic functional ingredient entrapped in polymeric beads, said entrapped ingredient being co~centrated near the surface of the sheet.
The method of making a wet wipe comprising a porous sheet impregnated with an aqueous lotion wherein the improvement comprises applying polymeric beads containing a hydrophobic functional ingredient.
By way of added explanation, the obj~cts of the present invention may be attained by providing a wet wipe comprising a porous sheet which is i~pregnated with an aqueous lotion and, concentrated near the surface of the sheet, polymeric beads containing a functional ingredient which is useful for treating the human skin or envir~nment surfaces and which are characterized in providing controlled release of the functional ingredient.
As used herein, the term "polymeric beads" shall mean any form of discrete, free-flowing powders or beads which envelope, coat or contain an active ingredient in a polymeric matrix or capsule. Such beads provide for the controllable release over time of the active ingredient either by rupture of the coating or matrix whereby the active ingredient is released when sufficient pressure or shearing action is applied to the bead or the coating or matrix may be semipermeable or porous to allow the active ingredient to diffuse out of the bead. Additionally, as will be appreciated by skill In the pertinent art, the application of heat may lower the viscosity of the entrapped material (or raise its vapor pressure) thereby causing more rapid release from the porous polymeric beads. "Polymeric beads" is intended to encompass microcapsules g2nerally; microcapsules being a well-known form of polymeric beads formed by emulsion polymerization. The term further includes beads ~ormed by polymer entrapment as described in Canadian Patent 1,168,157 and porous beads claimed in U.5. Patent 4, 690, 825 .

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- 2a -132~0 Entrapment in a polymer matrix is disclosed in Canadian Patent 1,168,157, issued May 29, 1984 to Eric S. Abrutyn, entitled "Polymer Entrapped Emollient-Moisturizer Composition". According to Abrutyn, water insoluble organic liquids and solids can be entrapped in a hydrophobic polymeric lattice. The polymeric lattice functions to hold and protect the entrapped material and i5 capable of providing availability of the entrapped material by a variety of mechanisms, particularly pressure. Such materials are commercially ~.

' ~,, ' ' 13~2~60 available from Wickhen Products, Inc. under the trademark POLYTRAP .
The term porous beacis or microsponges refers to the time-release delivery vehicles disclosed and claimed in U.S. Patent 4,690,825, granted September 1, 19B7 to Richard Won, Method for Delivering an Active Ingredient by Controlled Time Release Utilizing a Novel Delivery Vehicle which can be Prepared by a Procecs Utilizing the Active tngredient as a Porogenll.
All of these types of polymeric beads are characterized in 13 providing release of an active ingredient from a network of pores, while the shape of the en~rapping cavity and the external shape of the particular may vary. The POLYlRAP polymeric lattices and microsponges have in common the hature that the active or functional ingredient is trapped in a network of pores or cavities during polymerization. The active ingredient thereby has a substantially uniform concentratlon throughout the network of pores. This uniformity helps to create a more controlled release of the active ingredient from the network of pores over a given period of time (controlled time-release). As these structures provide a sustained release over a period of time as compared to a total release when the membrane of a microcapsule is broken, they are preferred for use in the present invention. Microcapsules are nonetheless capable of providing time release in many applications where nct all of the mlcrocapsules are ruptured at once.
The present inventor contemplates that a wide variety of water insoluble organic liquids and solids may be incorporated within the polymerlc beads. The term functlonal ingredient can be defined as any Ingredient whlch when released from the polymeric beads performs some functlon relative to the surface to which it is applled. Thus, If the wet wipes of the present Invention are to be applied to the human skin, the active Ingredient may be a drug or beauty aid and mlght comprlse anti-lnfectlves such as antiblotics, antimlcrobials and funglcldes, antipersplrants, deodorants, sunscreens, emollients, humectants and Insect repellants. If they , ' , .
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132~

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are to be used for wiping envlronmental surfaces in the home or for agricultural, food service, veterinary or medical applications, the func~ional ingredient might be a wax or polish, a fragrance, a disinfectant or an insecticide.
S The term "aqueous lotion", as used in this specification and the appended claims, refers to any aqueous solution, including hydrogels, and oil-in-water emulsions.
As will be appreciated by one of ordinary skill in the art to which the present invention pertains, the polymeric beads of the present invention are applied at concentrations which provide the transfer of an effective amount of the functional ingredient to the skin or surface when the pre-moistened sheet is pressed or rubbed against the skin or surface.
Celluloslc fibrous webs are preferred as the porous sheet for the wet wipe of the present invention because of their low cost and biodegradability. Especialiy preferred are paper, air-laid and carded non-woven webs. However, spun-bonded and spun-lace webs are also suitable. For applications where cost and/or blodegradability are not important, alveolar polymeric films, foam and other porous sheets may be employed. Techniques for moistening the wlpes and packaglng them in moisture impervious packages are well-known in the art and need not be elaborated here .
The t'eature whlch the present in~,~entor believes is fundamental to the success of' her inventlon is the concentration of the polymeric beads at or near the surface of the porous sheet. In this way the maxlmum amount of the functlonal ingredient which was applied to the sheet wlll be transferred to the surface to be treated. The present Inventor has l'ound that the polymerlc beads, because of thelr particulate nature, when applled to the surface of the sheet, tond to remaln near the surface of the sheet and not to penetrate the sh~et lik~ a llquld does. Most preferably, the polymeric beads are appl ied to the sheet before or after the sheet has been Impregnated with water or an aqueous lotlon. The beads In dry ~I
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Alternatively, they can be printed or roll coated in the form of a printing fluid or paste. Less preferably, thç polymeric beads can be combined with the aqueous lotion and applied to the web which 5 has already been wetted with water so that the polymeric beads are not carried into the interior of the web as readily when the lotion strikes through a dry web. It is also feasible to apply the polymeric beads with the aqueous lotion to a dry web. However, in the latter case, the beads will not be as concentrated near the 10 surface as when applied to a previously wetted web. The present inventor has found that a more cunvenient and efficient manufacturing process results when the step of combining the polymerlc beads with the aqueous lotion is avoided; i . e ., it is generally easier to apply the pvlymeric beads separately in dry form 15 than to disperse them uniformly }n the lotion. As will be understood by one skilled In the pertinent art, the selection of the method of application will be determined iargely by the intended use of the wet wipe, as will be illustrated by the following description of the preferred embodiments.
DETAILED DESCRIPTION OF THE INVENTION
The Invention wlll be further descrlbed with reference to the following detailed examples, whlch illustrate the preparation of wet wfpes for treating the human skin and envTronmental surfaces 25 utilizing the teachings of the present inventlon.
Emolllent olls generally function to lubricate the skin surface and to prevent evaporatlve loss of skln moisture supplied by underlying tlssue~. They also function to provide a protective barrier against envlronmental irrltants. The emollient oils useful in 30 the practlce of the present Inventlon include those commonly employed In the art such as liquid hydrocarbons, e.g., petrolatum, mlncral oll and th~ llke, vegetable and animal fats and oils, viz.
lanolln, phosphollplds and their derivatives and silicones.
Sllicones, especlally dimethlcones are preferred for providing a ~5~

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protective barrier and may consist of one or more of the commercially available dimethicones or linear polydimethylsiloxane polymers having a viscosity in the range of 50 to 1 000 centistokes.
Preferably the dimethicones will be present at about 0.5~ to 3û% by 5 weight of the web or porous sheet.

Example I
Non-Greasy Barrier Wipe A lotion formulated as shown below was used as a base lotion lO to lotionize an air-laid non-woven web having a basis weight of 68 grams per square meter to 3009~ of the web weigh~ (i.e. abou~ 200 grams lotion per square meter of web. ) The lotion was applied by immersing the web in the lotion followed by roll doctoring the web to the desired degree of saturation.

Ingredient 96 by Weight of Lotion Bronopol . 05 Methylparaben . 2 Propylparaben . 03 Propylene Glycol 1.5 Water to make up 100% Microsponges containing 50~ dim~thicone by welght were applied to each side of the non-woven web by fluidizing them in air and spraying them onto the web. The microsponges were applied to each side at the 25 rate of 5% of the dry web welght to make a product containing 10%
by welght mlcrosponges or 596 by weight dlmethicone. When used to wipe the skin the wipe deposited the microsponges and expressed dimethlcone onto the skin durlng the wiping action. The dimethicone layer on the skin provided a barrier to protect the 30 skln. The microsponges transferred to the skin contlnued to provlde time-release of dlmethlcone. Such a wipe may be used as a baby wipe to help prevent diaper rash.
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. . .-1325~0 Example i I
Low SPF Sun 5creen Wipe A spun lace web having a basis weight of 85 grams per square meter is lotionized using the formulation of Example I in the same manner and at the same rate. Microsponges containing a mixture of oxyben~one and octyl dimethyl p-amino benzoate in the ratio ~f one to three respective1y were applied to each side of the wetted non-woven web by the same method as in Example 1. The microsponges are applied to each side at the rate of 7% of the weight of the dry web to make a product containing 14% by weight of microsponges or 7% by weight of functional ingredients. The product is non-greasy and when rubbed onto the skin to be protected from sunburn provided protection against the burning , 15 rays of the sun; namely, UVA llight of 320 to 400 nanometers in wave length1 and UVB (light of 290-320 nanometers in wave length~
at a SPF ~Sun Protection Factor) le~el of 4 as measured by the procedure specified by the Food and Drug Administration in the Over-the-Counter Monograph on Sunscreen Drug Products for Over-the-Counter Human Drugs, Proposed Safety, Effective and Labelling Conditlons. Fed. Register. 43(166); 38206-38269, August 25, 1978.
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High SPF Sun Screen Wipe In the present exampie, sun blocking agents are also included in the ~ormulation used to lotlonlze the web, namely: ~
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~ % Welght of Lotion Oxybenzono 3 Ethylhexyl p-methoxy cinnamate 6 PPC-3 myrlstyl ether ~surfactant) 5 Isopropyl Myristate 4 ', ' .:

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~32~0 Glyceryl Stearate 2 Myristyl Alcohol 2 - PEG-20 methyl giucose sesq- istearate (emulsifier) 2 preservative 0.1 perfume o . 3 Water 75 4 Microsponges are then applied as in Example I i . The resulting . product is moisturizing to the skin and provides sunburn protection 10 at an SPF level of 20.

Example IV
Non-Greasy Moisturizing Wipe for Hand and Body - 15 An oil-in-water emulsion of the following formulation:

Ingredient % by Weight of Lotion Mineral ail 2 20 Propylene glycol 1.5 methylparaben 0.30 propylparaben 0 . 04 -' ethoxylated sorbltol 0.4 fatty acid estor (surfactant) Z5 water to make up 100%

, in which is dispersed POLYTRAP polymeric lattices contalning 80%
by weight dimethicone tn an amount equal to 2~ by weight of the emulslon Is applled at the rate of 3009~ by welght of the dry web to 30 a carded web made of a 50150 blend of polyester and rayon and havlng a basls welght of 51 grams per square meter by means of a constant flow applicator to the web which is moving at a controlled veloclty. Thls wlpe feels non-greasy and provides good molsturlzlng effect for the skln.

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~32~0 .~ g Example V
I nsect Repel lent Wipe The carded web of Example IV was lotionized with a 2% mineral 5 oil emulsion as described in Example IV which included in place of the polymeric beads oontaining dimethioone microsponges loaded with the insect repellent DEET-diethyl toluamide at 50% by weight were uniformly dispersed in the lotion at 5% by lotion weight. This wipe provided the insect repelling function but with a more pleasant feel 10 because of the controlled release of the DEET from the polymeric beads and the lubricating effect of the mineral oil. Moreover the mineral oil would have been difficult to include had the DEET not been entrapped in the polymeric beads. ~;

Example Vl Barrier Wipe for Dry Skin A non-woven web made of 100~ wood pulp having a basis weight of 68 grams per square meter is lotionized by the method 20 described In Example IV to 280% of the dry web weight with an emulslon lotion containing 3% dimethicone as shown beiow.
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. dimethicone 3 ethoxylated sorbitol C.5 .! 25 fatty acid ester (surfactant) methylparaben 0 . 2 propylparaben 0 . 03 bronopol 0 . 05 water to make up 100%
: 30 A paste conslsting of 70~ by weight microsponges containlng 50% by welght mlneral oil and of 30% of distllled water is then prlnted onto the iotionized web by using a gravure roll. Uslng this technique ~ .
said microsponges were applied to each side at the rate of 79~ by , . .
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dry weight of the web to make a product containing 1 4~s by weight microsponges or 7% of mineral oil. This wipe product i5 moisturizing and provides an enduring barrier effect ~o dry skin.

5Example Vll Lubricating Shaving Wipe for Legs A non-woven carded web as described in Exarnple IV is lotionized with an aqueous lotion as described in Example I to 250%
10of the dry web weight. Microcapsules containing dimethicone are then applied to the lotionized web as in Example 1. This product -can be used for lubricating skin prior to shaving the legs.

Example V l l l t5Cleansing and Waxing Wlpe for Furnitures An airlay web as described in Example I is lotionized with a base lotlon as described below to 285% of the dry web welght.

ethoxylated sorbltol 0.5 3 fatty acid ester (surfactant) methylparaben 0, 2 propylparaben 0 . 03 ~, 25 propylene glycol 1.5 bronopol 0.05 water to make up 100% :

Mlcrosponges contalnlng furnlture wax are then applied to the 30 lotlonlzod web by the m~thod descrlbed In Example I to the extent of 30% of the dry web weight, This prociuct is useci to clean and wax furniturc In one step.
Whlle certaln representative embodlments of the invention have beon ciescrlbed hereln for purposes of Illustratlon, it will be . I . . - .
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may be made without parting from the spirit and scope of the invention as defined by the appended claims.

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Claims

1. A porous sheet impregnated with an aqueous lotion comprising a hydrophobic functional ingredient entrapped in polymeric beads, said entrapped ingredient being concentrated near the surface of the sheet.

2. The sheet according to Claim 1 wherein the beads are microsponges.

3. The sheet according to Claim 1 wherein the beads are microsponges in the form of a polymeric matrix.

4. The sheet according to Claim 1 wherein the beads are microcapsules.

5. The sheet according to Claim 1 wherein said functional ingredient is dimethicone present in an amount between 0.5% to 30%
by weight of the porous sheet.

6. The method of making a wet wipe comprising a porous sheet impregnated with an aqueous lotion wherein the improvement comprises applying polymeric beads containing a hydrophobic functional ingredient.

7. The method of Claim 6 wherein said beads are applied in dry form.

8. The method of Claim 6 wherein said beads are applied in the form of a paste.

9. The method of Claims 6 7 or 8 wherein said beads are applied before the sheet is impregnated with the aqueous lotion.

10. The method of Claims 6. 7 or 8 wherein said beads are applied after the sheet Is impregnated with the aqueous lotion.

11. The method of Claim 6 wherein said beads are mixed with the aqueous lotion when applied to the sheet.