WO2001066421A1

WO2001066421A1 - Gas-venting container

Info

Publication number: WO2001066421A1
Application number: PCT/US2000/000924
Authority: WO
Inventors: Mari Yanagida; Satoshi Yamene; Michael Ming-Jae Lin
Original assignee: The Procter & Gamble Company
Priority date: 2000-01-14
Filing date: 2000-01-14
Publication date: 2001-09-13
Also published as: JP2003525820A; AU2612200A

Abstract

A container (10) includes a housing (12) which includes an interior and an exterior. The interior defines an internal surface area (14) which includes a three-dimensional pattern (20) which increases the internal surface area by at least about 20 %, as compared to a container lacking the three-dimensional pattern (20). The internal surface area (14) also defines a container volume containing an O2-generating composition therein. The O2-generating composition fills less than about 95 % of the container volume. The container has an O2 passage rate of at least about 0.3 mL O2/ atm * 24 hours * L of container volume, regardless of the orientation of the container.

Description

GAS-VENTING CONTAINER

FIELD OF THE INVENTION The present invention relates to containers. Specifically, the present invention relates to containers for holding a composition which evolves gas.

BACKGROUND OF THE INVENTION Compositions containing oxygen bleaches have recently become very popular for cleaning clothes and fabrics, and removing mildew. Oxygen bleaches are preferable because of their low odor and safety on colored items, as compared to hypochlorite-based bleaches.

Liquid and solid oxygen bleaches may decompose to generate O₂ gas during shipping and/or storage. This is especially likely when an oxygen .pleach is included in a liquid composition. If the container is air-tight, then the generated 0₂ gas may build up within the container and cause unsightly bulging, or even rupture of the container. Such bulging and rupture of the container is highly undesirable.

This problem has been addressed by forming containers which allow generated 0₂ gas to pass through a venting mechanism, such as a valve. As O₂ gas is generated, it typically rises to the top of the container, and passes though a valve which is typically located at the highest point of the container. The venting mechanism allows gases to pass through, while retaining liquids and/or solids within the container. Such a container and/or venting mechanism are typically difficult, expensive, and/or complicated to form and assemble. In certain cases, such venting mechanisms may even need to be assembled by hand; this greatly increases production costs. Furthermore, such venting mechanisms only allow O₂ to pass through when, the container is shipped and stored in an upright orientation. If the container is shipped or stored on its side, or upside-down, then it is unlikely that the evolving O₂ gas will collect near the venting mechanism, because it is no longer at the highest point of the container. In this case, very little generated 0₂, if any, passes through the venting mechanism, and thus, 0₂ gas will build up within the container.

Alternatively, certain materials, such as plastics and polymers, may permit O₂ gas to pass directly though the material itself. The amount of gas which passes through such a material is dependent upon factors such as the internal surface area of the container, the thickness of the material, the internal fill volume of the liquid, the atmospheric pressure and partial pressure of the gas, the type of gas itself, and time. With such a container, the generated 0₂ rises to the top of the container and passes through the material in the upper portion of the container. Thus, it is known to form a container from such a gas-venting material, in order to hold an O₂-generating liquid.

However, these containers are only designed with a single orientation in mind. These containers fail to take into account the chance that containers may be shipped and/or stored sideways, or even upside-down. In the typical container, the bottom is thicker than the top and the sides, so as to impart greater structural rigidity to the container. As the gas passage rate of a material is inversely proportional to the thickness of the material, this thicker bottom vents gas much more slowly than the thinner top. Thus, an upside-down container may not allow sufficient gas to pass through the thicker bottom, which again leads to a build up of O₂ gas and pressure within the container.

Other containers are known to contain a silver halide photographic processing solution which precipitates when insufficient 0₂ is present in the container. To increase the 0₂ passage rate into the container, the container has a bellows-shaped body, which increases the surface area of the container. This increased surface area allows more 0₂ to enter the container, and thus reduces precipitation of the photographic bleaching agent. Such processing solutions do not actually evolve 0₂ gas, but instead, react with it.

Accordingly, the need exists for a container which provides improved O₂ venting characteristics, regardless of the orientation of the container. The need also exists for a container which provides the above advantages, and is inexpensive to produce. SUMMARY OF THE INVENTION

The present invention relates to a container which includes a housing which includes an interior and an exterior. The interior defines an internal surface area which includes a three-dimensional pattern which increases the internal surface area by at least about 20%, as compared to a container lacking the three-dimensional pattern. The internal surface area also defines a container volume containing an 0₂-generating composition therein. The O₂-generating composition fills less than about 95% of the container volume. The container has an O₂ passage rate of at least about 0.3 mL O₂ / atm * 24 hours * L of container volume, regardless of the orientation of the container.

It has now been found that a container may be formed which is both structurally sound and which possesses an acceptable 0₂ passage rate regardless of the orientation of the container. The container may contain therein an 0₂-generating composition without bulging and/or rupturing, even when the container is not shipped/stored in an upright orientation. The three-dimensional pattern of the internal surface provides an increased 0₂ passage rate and may also increase the structural strength of the container. The container is easy to manufacture, and avoids the need for expensive venting mechanisms.

These and other features, aspects, advantages, and variations of the present invention, and the embodiments described herein, will become evident to those skilled in the art from a reading of the present disclosure with the appended claims, and are covered within the scope of these claims.

BRIEF DESCRIPTION OF THE DRAWINGS While the specification concludes with claims particularly pointing out and distinctly claiming the invention, it is believed that the invention will be better understood from the following description of preferred embodiments which is taken in conjunction with the accompanying drawings in which:

Fig. 1 is a partially cut-away side view of a preferred embodiment of the container of the present invention;

Fig. 2 is a partially cut-away side view of a comparative container lacking a three-dimensional pattern;

Fig. 3 is a^' side view of a preferred embodiment of the container of the present invention. Fig. 4 is a magnified, perspective view of the container of Fig. 3, as seen when cut along line 4-4; and

Fig. 5 is a magnified, perspective view of an alternate embodiment of the container of the present invention.

DETAILED DESCRIPTION OF THE INVENTION All percentages, ratios and proportions herein are by weight of the 0₂- generating composition, unless otherwise specified. All temperatures are in degrees Celsius (°C) unless otherwise specified. All documents cited are incorporated herein by reference in their entireties. Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention. The drawings herein are not necessarily drawn to scale.

As used herein, the term "alkyl" means a hydrocarbyl moiety which is straight or branched, saturated or unsaturated. Unless otherwise specified, alkyl moieties are preferably saturated or unsaturated with double bonds, preferably with one or two double bonds. Included in the term "alkyl" is the alkyl portion of acyl groups.

Referring to the drawings, Fig. 1 shows a partially cut-away side view of a preferred embodiment of the container of the present invention. In Fig. 1 , the container, 10, has a housing, 12, for containing an 0₂-generating composition.

The housing, 12, has an interior, 14, and an exterior, 16. The interior, 14, defines an interior surface area, 18, which contains a three-dimensional pattern,

20. The three-dimensional pattern, 20, is shown in Fig. 1 as a plurality of rings in the interior, 14, of the housing, 12. Specifically in Fig. 1 , the three-dimensional pattern is formed by a series of rings which are visible in both the interior, 14, and the exterior, 16, of the housing, 12, which increases the internal surface area by

20%, as compared to the container of Fig. 2. From the outside of the container,

10, of Fig. 1 , the three-dimensional pattern, 20, is visible as an indentation, 22, on the exterior, 16. In Fig. 1 , the three-dimensional pattern, 20, also increases the side-compression force and structural rigidity of the container, 10.

The three-dimensional pattern herein may be any pattern which increases the internal surface area by at least about 20%, preferably from about 30% to about 200%, and more preferably from about 50% to about 150%, as compared to a container lacking the three-dimensional pattern (see comparative Fig. 2). The magnitude of the increase in the interior surface area can be adjusted by adjusting the size, density, depth, and other physical characteristics of the three- dimensional pattern.

The increase in the internal surface area is measured by a computer- aided design (CAD) program. Most CAD programs used for industrial modeling and product fabrication/design can easily and quickly measure the interior surface area of a container, once data about the dimensions and internal features thereof are input. From this information, one can determine the O₂ passage rate for the container, and/or per liter of container volume. A preferred CAD program is "Solid Works," available from Solid Works Corporation, of Massachusetts, USA. It is highly preferred that the CAD program itself calculate the 0₂ passage rate for a container, at a given orientation and fill volume. For example, in Fig. 2, the internal surface area of the container would be calculated via a CAD program, by entering information about the container interior's diameter, the angle of the conical top, etc. The CAD program may then easily calculate the surface area based on the combination of a cylinder, and a conical top. Similarly, for the container of Fig. 1 , the internal surface area may be calculated by adding the additional surface area of the raised internal ridges which form the three-dimensional pattern. From this internal surface area calculation, an 0₂ passage rate for a given orientation and a given fill level may also be calculated.

Generally, the O₂ passage rate for a given material is determined by factors such as the container material itself, the thickness of the container material, and the available surface area through which the 0₂ may pass. The O₂ passage rate for a given material may be found in standard texts (see Manufacturing Method of High-barrier Property Packaging Material and Design. Manufacturing Technology and Usage Expansion, p. 7, published by the Technical Information Association (Gijutsu Jouhou Kyoukai) of Tokyo, Japan, (September 28, 1998)), and/or may be calculated according to the following formula: Q = (P * ΔP * A) / T (Formula I), where Q is the O₂ gas permeation rate in mL / 24 hours at 1 atmosphere pressure. P represents the permeation coefficient which is dependent upon the type of gas, the thickness and type of material, etc. Values for P may be found in the literature and in standard texts. P has the units mL / (m * atm * 24 hours). ΔP is the difference in partial pressure between the inside and outside of the container; i.e., ΔP = (partial 0₂ gas pressure inside the container) - (partial 0₂ gas pressure outside the container). ΔP has the units of atm. In Formula I, A represents the permeable surface area of the container, in square meters, while T represents the thickness of the container material in meters. By increasing the internal surface area, the three-dimensional pattern increases the amount of permeable surface area, and therefore the overall O₂ passage rate of the container.

By dividing the 0₂ gas permeation rate, Q, by the volume of the container, one can find the 0₂ passage rate of the container, at a given fill volume. The container herein has an O₂ passage rate of at least about 0.3 mL O₂ / atm * 24 hours * L of container volume, preferably from about 0.4 mL O₂ / atm * 24 hours * L of container volume to about 40 mL 0₂ / atm * 24 hours * L of container volume, and more preferably from about 0.5 mL 0₂ / atm * 24 hours * L of container volume to about 7 mL 0₂ / atm * 24 hours * L of container volume, regardless of the orientation for the container. In order to prevent bulging and gas build up within the container, it is essential that the 0₂ passage rate of the container be greater than the O₂ evolution rate of the 0₂-generating composition, described below.

The permeable area is also dependent upon the fill level of the O₂- generating composition within the container volume. As noted above, it is believed that as 0₂ gas is generated, it rises to the "highest point" of the container, and then escapes from this highest point. This is especially true when the container volume contains therein a liquid 0₂-generating composition, as it is believed that the 0₂ passage rate is negligible in areas of the container which are covered by liquid. Accordingly, the permeable area, A, is calculated as the interior surface area of the interior of the housing which does not contact the O₂- generating composition at the given fill level. Accordingly, it is important that during shipping and/or storage, the O₂-generating composition fills less than about 95%, preferably from about 70% to about 95%, and more preferably from about 75% to about 90% of the container volume.

The three-dimensional pattern typically comprises a plurality of individual units, such as a ring (e.g., Fig. 1 at 20), a dimple (e.g., Fig. 3, at 20), a straight or curved line (not shown), and a mixture thereof. Such individual units may be used singly, or combined to form a three-dimensional pattern containing a design, a trademark, a picture, a frictional surface, a structural support, and a combination thereof. Preferably, the three-dimensional pattern forms a frictional surface which improves the user's grip on the container, and which reduces slippage thereof. The three-dimensional pattern may project into the interior of the housing (see Fig. 1), and/or may project out from the exterior of the housing (see Fig. 4). Preferably, the three-dimensional pattern is substantially evenly distributed across the interior of the housing, so that the 0₂ passage rate is substantially the same, regardless of the orientation of the container. In a highly preferred embodiment, the three-dimensional pattern is distributed substantially evenly across the interior of the housing, such that the O₂ passage rate varies by less than about 50%, preferably by less than about 25%, and even more preferably by from about 0% to about 15%, regardless of the orientation of the container, when it contains the 0₂-generating composition.

The three-dimensional pattern herein is typically formed as part of the container-forming process, such as by blow molding, embossing, injection molding, injection blow molding, vacuum forming, thermoforming, and combinations thereof; preferably, the three-dimensional pattern is formed by embossing. The container itself typically comprises a material selected from the group consisting of polymers, plastics, and mixtures thereof; preferably selected from the group consisting of polyethylene, polypropylene, ethyl-vinyl-acetate, polystyrene, polycarbonate, poly-4-methylpentene-1 , a microporous membrane, and combinations thereof; more preferably selected from the group consisting of a linear low-density polyethylene, an oriented polypropylene, and combinations thereof. Suitable materials are available from 3M Company (St. Paul, Minnesota, USA), Du Pont Co. (Wilmington, Delaware, USA), Toppan Insatsu Co. (Tokyo, Japan), and Gelman Sciences Company (Ann Arbor, Michigan, USA).

In Fig. 1 , the thickness of the housing, 12, is substantially the same, throughout the entire container, 10. However, such a uniform housing thickness is not required in the present invention (see, Fig. 5). The thickness of the housing may vary from container to container, but is dependent upon factors such as the structural requirements of the container, the desired 0₂ passage rate, the container material itself, etc. In practice, the container will typically have a thickness of less than about 3 mm, preferably from about 0.02 mm to about 1.2 mm, and more preferably from about 0.1 mm to about 0.8 mm, for improved resiliency and squeezability. In Fig. 1 , the container, 10, also has a cap, 24, which seals the housing, 12, and prevents leakage of the 0₂-generating composition therefrom. In other words, the cap, 24, and the housing, 12, form a seal which is substantially impervious to the 0₂-generating composition, even if the container is shipped or stored in a sideways or upside-down orientation. The cap, 24, further contains a plurality of optional frictional surfaces, 26, thereupon, to allow easy opening and/or closing of the cap, 24. Such a cap may form a seal via a screw-type closure, a snap-type closure, a hinge-type closure, a sliding closure, and combinations thereof. From a manufacturing standpoint, a snap-type closure, and a screw-type closure are preferred, as they are inexpensive to form, even if they are water-tight seals.

An optional feature which may be included wherever a water-tight seal is desired is an inner plug seal, a trigger seal, and/or any of many well-known contact-ring seals. These types of gasketless seals are surprisingly water-tight. Alternatively, a separately-formed, or an integrally-formed gasket-type seal may also be used herein. In a highly preferred embodiment, the cap is also made of a material which allows O₂ gas to pass through, as described above. If desired, the cap may further contain a three-dimensional pattern thereupon, so as to increase the 0₂ passage rate of the cap. The optional three-dimensional pattern may be in combination with a frictional surface, or may also serve as a frictional surface.

Fig. 2 shows a partially cut-away view of a partially cut-away side view of a comparative container lacking a three-dimensional pattern. In Fig. 2, the comparative container, 40, also contains a housing, 42, having an interior, 44, and an exterior, 46, and an interior surface area, 48, in the interior, 44. The comparative container, 40, also contains a cap, 50, to seal the housing, 42. However, the comparative container, 40, lacks a three-dimensional pattern, as defined herein. Therefore, even if all other dimensions are the same, the comparative container of Fig. 2 has an inherently smaller interior surface area than the container of Fig. 1.

Fig. 3 shows a side view of a preferred embodiment of the container of the present invention. In Fig. 3, the container, 10, has a plurality of small, three- dimensional patterns, 20, on the exterior, 16, of the housing, 12. With so many small, three-dimensional patterns, 20, thereupon, the container, 10, may have a significantly increased interior surface area, as compared to a comparable container lacking such a three-dimensional pattern (not shown). For example, such a plurality of small, three-dimensional patterns, e.g., dimples, may increase the internal surface area of the container, by 50%, or more. Such containers, including non-limiting examples of preferred three-dimensional pattern depth, three-dimensional pattern size, and three-dimensional pattern density are provided in Examples 1 and 2.

The container, 10, of Fig. 3 also has a handle, 28, formed by the housing, 12, which allows a user to easily hold the container, 10, and to pour the O₂- generating composition out of the container, 10. The handle, 28, also contains a plurality of three-dimensional patterns, 20, thereupon.

Fig. 4 shows a magnified, perspective view of the container of Fig. 3, as seen when cut along line 1-1. The interior, 14, contains a plurality of small, three-dimensional patterns, 20, which greatly increase the interior surface area, 18. The three-dimensional pattern, 20, is also visible on the exterior, 16, of the housing, 12, as a plurality of dimples. Such an arrangement is highly advantageous, as the three-dimensional pattern may also serve as a frictional surface. It is preferred that the three-dimensional pattern of Fig. 4 be formed by embossing.

Fig. 5 shows a magnified, perspective view of an alternate embodiment of the container of the present invention. Fig. 5 shows a container of the present invention which is cut along a line, as in Fig. 3, and then viewed edge-wise. In the close-up, edge-wise view of Fig. 5, the interior, 14, of the housing, 12, contains a three-dimensional pattern, 20, which is not visible on the exterior, 16, of the housing, 12. A container having such a three-dimensional pattern which is not visible or noticeable from the exterior of the container may be especially useful, as it may reduce the amount of material required to form the container, while still achieving an increase in interior surface area. This in turn can significantly save on materials costs. It is preferred that such a container be formed by thermoforming. In order to survive the container-filling process and machinery, the container herein is preferably a bottle, such as described in the figures. However, containers which are too soft are difficult to fill in an automated process, or may easily break. In contrast, a container which is too hard may be disliked by consumers who prefer resilient containers. Therefore, it is highly preferred that the container have a side-compression force of at least 20 N, preferably from about 100 N to about 400 N, and more preferably from about 100 N to about 200 N. The side-compression force is measured as the amount of external force required to deform the container and thereby reduce its width by 10%, as compared to a container to which no force is applied. The side- compression force is preferably measured when the container is empty, and unsealed (i.e., without a cap). Preferably, the side-compression force is measured at a point near the center of the container. Such a container both survives the filling process, and is aesthetically pleasing to a consumer because it is slightly resilient. The container may further include additional items such as designs, labels, decorations, and/or instructions which are desirable by the consumer. However, such additional items preferably do not reduce the 0₂ passage rate below the O₂ evolution rate of the O₂-generating composition; especially if a label is present. Thus, the label itself may also have an 0₂ passage rate, as described herein.

The container may be of any size and volume. For consumer products, a preferred container has a container volume of from about 100 mL to about 5 L, preferably from about 200 mL to about 3 L, and more preferably from about 500 mL to about 2 L. The present invention may be used in combination with one or more additional venting mechanisms, such as, but not limited to, a venting module, a semi-permeable membrane, a venting passage, a venting hole, a valve, and combinations thereof.

O.-GENERATING COMPOSITION

The container of the present invention contains an O₂-generating composition therein. The O₂-generating composition is typically a cleaning, bleaching, and/or disinfecting composition containing a source of active oxygen. The O₂-generating composition may be in any form, such as a solid, liquid, gel, or combination thereof. However, the container of the present invention is especially useful where the O₂-generating composition is a liquid O₂-generating composition. In a preferred embodiment, the O₂-generating composition is an oxygen bleach composition, and more preferably the O₂-generating composition is a liquid oxygen bleach composition. The oxygen bleach composition comprises therein an active oxygen source such as hydrogen peroxide, an active-oxygen-producing enzyme, a peracid and/or a per-salt, or a mixture thereof; more preferably hydrogen peroxide, an alkali metal percarbonate, an alkali metal perborate, a peroxidase enzyme, or a mixture thereof. The 0₂-generating composition typically contains therein from about 1% to about 30%, preferably from about 1% to about 15% of an active oxygen source, by weight of the composition. If the active oxygen source is hydrogen peroxide, then the 0₂-generating composition typically contains, therein from about 1% to about 15%, preferably from about 1 % to about 6% hydrogen peroxide, by weight of the composition.

To reduce bulging and/or rupture, the O₂-generating composition should have an O₂ evolution rate which is less than the O₂ passage rate of the container. Preferably, the O₂-generating composition has a 0₂ evolution rate of less than 0.6 mL / 24 hours * L of 0₂-generating composition; more preferably less than 0.4 mL / 24 hours * L of O₂-generating composition; and even more preferably less than 0.3 mL / 24 hours * L of O₂-generating composition.

The oxygen bleach composition also typically comprises therein other optional ingredients, such as a surfactant, a chelant, a buffering system, and combinations thereof. Preferred surfactants useful herein include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and combinations thereof. Combinations of anionic surfactants, amphoteric surfactants, and nonionic surfactants are especially preferred. Nonlimiting examples of the surfactant useful in the detergent composition include, the conventional C^-C^ alkyl benzene sulfonates and primary, branched-chain and random C₁₀-C₂₀ alkyl sulfates, the C₁₀-C₁₈ secondary (2,3) alkyl sulfates of the formula CH₃(CH₂)_x(CHOS0₃-M+) CH₃ and CH₃ (CH₂)_y(CHOS0₃-M+) CH₂CH₃ where x and (y + 1) are integers of at least about 7, preferably at least about 9, and M is a water-solubilizing cation, especially sodium, unsaturated sulfates such as oleyl sulfate, the C₁₀-C₁₈ alkyl alkoxy sulfates (especially EO 1-7 ethoxy sulfates), C₁₀-C₁₈ alkyl alkoxy carboxylates (especially the EO 1-5 ethoxycarboxylates), the C₁₀-C₁₈ glycerol ethers, the C₁₀-C₁₈ alkyl polyglycosides and their corresponding sulfated polyglycosides, and C₁₂-C₁₈ alpha-sulfonated fatty acid esters. If desired, the conventional nonionic and amphoteric surfactants such as the C₁₂-C₁₈ alkyl ethoxylates including the so-called narrow peaked alkyl ethoxylates and C₆-C₁₂ alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C₁₂-C₁₈ betaines and sulfobetaines, C₁₀-C₁₈ amine oxides, and the like, can also be included in the overall compositions. The C₁₀-C₁₈ N-alkyl polyhydroxy fatty acid amides can also be used. Typical examples include the C₁₂-C₁₈ N-methylglucamides. See WO 92/06154 to Cook, et al., published April 16,1992. Other sugar-derived surfactants include the N-alkoxy polyhydroxy fatty acid amides, such as C₁₀-C₁₈ N-(3-methoxypropyl) glucamide. The N-propyl through N-hexyl C₁₂-C₁₈ glucamides can be used for low sudsing. C₁₂-C₂₀ conventional soaps may also be used. Highly preferred nonionic surfactants useful herein include those of the formula:

R_rO-[(R₂0)_n(R₃O)_m]-R₄ (Formula I), wherein R.* is a C.*-C₂₅ alkyl, and wherein R₂ is a C₂-C₄ aliphatic hydrocarbyl chain. Preferably, R₂ is a C₂-C₃ aliphatic hydrocarbyl chain. R₃ is selected from the group consisting of a methyl mono-substituted C₂-C₄ aliphatic hydrocarbyl chain, and an ethyl mono-substituted C₂-C₄ aliphatic hydrocarbyl chain; preferably R₃ is selected from the group consisting of a methyl mono-substituted C₂-C₃ aliphatic hydrocarbyl chain, and an ethyl mono-substituted C₂-C₃ aliphatic hydrocarbyl chain. R₄ is selected from the group consisting of H, a C,-C₂₅ alkyl chain, and a C,-C₂₅ carboxyl chain, wherein n is an integer from 1 to 10, and wherein m is an integer from 1 to 20. Highly preferred nonionic surfactants include the Dobonol series from Shell Chemical Co. (Houston, Texas, USA).

The 0₂-generating composition typically comprises at least about 0.01 %; more preferably at least about 0.1 %; more preferably at least about 1 %; more preferably still, from about 1% to about 55% of a surfactant. Preferably, the 0₂- generating composition contains therein from about 0.1 % to about 30%, more preferably from about 0.5% to about 25% of an alkoxylated surfactant, by weight of the composition.

A chelant is useful herein to reduce degradation of the active oxygen source which may be catalyzed by trace amounts of metal ions. Chelants especially useful herein include 1-hydroxyehylidene-1 ,1-diphosphonic acid, butylated hydroxy toluene, ethylene diamine tetra acetate, ethylenediamine disuccinate, and mixtures thereof. The 0₂-generating composition typically comprises from about 0.1 % to about 15%, more preferably 0.1 % to about 3% of a chelant, by weight of the composition. The buffering system useful herein maintains the pH of a liquid 0₂- generating composition at a pH where the active oxygen source is relatively stable. Typically, the buffering system maintains the pH of the composition at a pH of less than about 7, preferably less than about 6, more preferably between about 3 and about 6.5, and even more preferably between about 3 and about 5. Buffering systems useful herein are well-known in the art and typically contain therein an acid and an alkaline salt. As such, the 0₂-generating composition typically comprises from about 0.3% to about 20%, preferably from about 0.5% to about 15% of an acid, by weight of the composition. In a highly preferred embodiment, the 0₂-generating composition contains a suds supressor therein to reduce or prevent undesirable foaming. Preferred suds supressors include silicone derivatives, high molecular weight hydrocarbons, N-alkylated amino triazines, and alcohols known in the art. See, for example, Kirk Othmer Encyclopedia of Chemical Technology, Third Edition, Volume 7, pages 430-447 (John Wiley & Sons, Inc., 1979). When present, the O₂-generating compositions herein will generally comprise from 0.1 % to about 5% of a suds supressor, by weight of the composition.

Other adjunct ingredients commonly used in detergent and bleaching compositions are also useful in the 0₂-generating composition herein. Nonlimiting examples of such an adjunct ingredient includes a dye, an alcohol, a perfume, an enzyme, a preservative, and a mixture thereof.

Examples of the invention are set forth hereinafter by way of illustration and are not intended to be in any way limiting of the invention.

EXAMPLE 1

Four identical 1 liter containers of the present invention according to Fig. 3 are formed of 0.6 mm thick high density polyethylene. The three-dimensional pattern is formed of a plurality of embossed dimples according to Fig. 4, with each dimple having a diameter of about 1 mm, and a depth of about 0.5 mm, when measured from the interior of the housing. The dimple density is about 80 dimples per cm², which corresponds to an internal surface area increase of about 20%, as compared to a container lacking the three-dimensional pattern. The three-dimensional pattern substantially covers the entire container, such that the 0₂ passage rate is about 2.0 mL O₂ / 24 hours, regardless of the orientation of the container. The cap is also formed of high density polyethylene. The container has a side-compression force of about 150 N.

Each container is filled with 900 mL of one of the oxygen bleach com ositions A-D, described below, which fill u 90% of the container volume.

t 1-hydroxyehylidene-1 ,1-diphosphonic acid tt butylated hydroxy toluene EXAMPLE 2 A 1 liter container of the present invention is formed according to Example 1 , except that the cap is formed of polyethylene, and there is no handle. Furthermore, each dimple has a diameter of about 0.5 mm, and a depth of about 0.25 mm, when measured from the interior of the housing. The dimple density is about 400 dimples per cm², which corresponds to an internal surface area increase of about 78%, as compared to a container lacking the three-dimensional pattern. The container's O₂ passage rate is about 2.8 mL 0₂/atm * 24 hours, regardless of the orientation of the container. The container contains 890 mL of oxygen bleach composition A, which fills

89% of the container volume.

Claims

WHAT IS CLAIMED IS:

1. A container comprising a housing comprising an interior and an exterior:

A. the interior defining an internal surface area, wherein the internal surface area comprises a three-dimensional pattern which increases the internal surface area by at least about 20%, as compared to a container lacking the three-dimensional pattern; and

B. the internal surface area defining a container volume containing an 0₂-generating composition therein, wherein the O₂-generating composition fills less than about 95% of the container volume, wherein the container has an 0₂ passage rate of at least about 0.3 mL O₂ / atm * 24 hours * L of container volume, regardless of the orientation of the container.

2. The container of Claim 1 , wherein the container has a side-compression force of at least 20 N.

3. The container of Claim 1 , wherein the three-dimensional pattern is formed by embossing.

4. The container of Claim 1 , wherein the housing is formed by a material selected from the group consisting of polyethylene, polypropylene, ethyl- vinyl-acetate, polystyrene, polycarbonate, poly-4-methylpentene-1 , a microporous membrane, and combinations thereof.

5. The container of Claim 1 , wherein the three-dimensional pattern increases the internal surface area by from about 30% to about 200%.

6. The container of Claim 1 , wherein the 0₂-generating composition is an oxygen bleach composition.

7. The container of Claim 6, wherein the oxygen bleach composition comprises, by weight of the composition:

A. from about 1% to about 15% hydrogen peroxide;

B. from about 0.1 % to about 30% of an alkoxylated surfactant; and C. from about 0.3% to about 20% of an acid, wherein the pH of the oxygen bleach composition is less than about 6.

8. The container of Claim 7, wherein the oxygen bleach composition further comprises a suds supressor.

9. The container of Claim 7, wherein the alkoxylated surfactant has the formula:

R O-[(R₂O)_n(R₃O)J-R₄ (Formula I), wherein R₁ is a C₁-C₂₅ alkyl, wherein R₂ is a C₂-C₄ aliphatic hydrocarbyl chain, wherein R₃ is selected from the group consisting of a methyl mono- substituted C₂-C₄ aliphatic hydrocarbyl chain, and an ethyl mono- substituted C₂-C₄ aliphatic hydrocarbyl chain, wherein R₄ is selected from the group consisting of H, a C C₂₅ alkyl chain, and a C..-C₂₅ carboxyl chain, wherein n is an integer from 1 to 10, and wherein m is an integer from 1 to 20.

10. The container of Claim 7, wherein the pH of the oxygen bleach composition is less than about 7.