CA2335639A1 - Packaged prodcut and device with dispensing means - Google Patents

Abstract

The present invention relates to a packaged product for dispensing a liquid, comprising a liquid-containing reservoir and a porous membrane, the reservoi r comprising an outlet, wherein the membrane is hermetically sealed to or arou nd the reservoir so that fluid passing through the outlet must pass across the membrane, and in that the combination of the liquid and the membrane results in a bubble point greater than 1 kPa, when measured at ambient temperature a nd pressure using the packaged liquid. The invention also relates to a device f or dispensing a liquid, comprising a liquid reservoir and a porous membrane, th e reservoir comprising an outlet, wherein the membrane is hermetically sealed to or around the reservoir so that fluid passing through the outlet must pass across the membrane, and wherein the membrane has an average pore size of fr om 1 to 100 micrometers and a thickness of less than 1mm.

Description

PACKAGED PRODUCT AND DEVICE WITH DISPENSING MEANS

OF THE INVENTION
This invention rE;lates to a device designed primarily for dispensing or applying a liquid from a reservoir, for example, a~bottle or a sponge; and to the 2o packaged product comprising the device containing a liquid.
Many packaged products are sold in containers which have an element disposed at the outlet of the container which is designed to control the flow of the liquid out of the contaiiner. Products sold in dispensing containers include paint, glue, shoe polish, health and beauty care lotions, various food and beverage products and various detergent products. The combination of the container and the element may be designed to facilitate dispensing, for example the teat on a drinks bottle, in particular for babies; or to control the flow of liquid from the container, for example a "non-drip valve" on a sauce bottle. One common dispensing element is made from silicone based compounds and has an opening which is activated by internal pressure such as by squeezably deforming the bottle, or by a baby sucking on the dispensing element. Some dispensing elements are designed to act like a valve which only opens when a predetermined internal pressure is exceeded.
s Another known packaged product for dispensing a liquid comprises a liquid-containing reservoir and a non-flexible, non-defc~mable plastic resin dispensing element. US-A-4 050 826, issued on Sept. 27~' 1977, relates particularly to antiperspirantldeodorant dispensers comprising a porous, sintered, synthetic ~o plastic dome as the dispensing element. The liquid is intended to drain out of the pores, and return to the container, after the applicator has been used.
It is an object of the present invention to provide a device, especially a packaged product, for dispensing a liquid that can be easily designed to be non-drip and non-spill, without the need for an expensive valve component. In one embodiment of the present invention the device gives an even and controlled dispensing. In another embodiment of the present invention the device gives a very high rate dispensing without any dripping of liquid when the dispensing is stopped.
SUMMARY OF THE INVENTION
The present invention relates to a packaged product for dispensing a liquid, comprising a liquid-containing reservoir and a porous membrane, the reservoir comprising an outlet, characterised in that the membrane is hem~eticafly sealed to or around the reservoir so that fluid passing through the outlet must pass across the membrane, and that the combination of the liquid and the membrane results in a bubble point greater than 1 kPa, when measured at ambient 3o temperature and pressure using the packaged liquid.

Another embodiment of the present invention relates to a device for dispensing a liquid, comprising a liquid reservoir and a porous membrane, the reservoir comprising an outlet, and the membrane being hermetically sealed to or around the reservoir so that fluid passing through the outlet must pass across the membrane, wherein the membrane has an average pore size of from 1 to 100 micrometers and a 'thickness of less than 1 mm.
DETAILED DESCRIPTION C?F THE 1NVENTIC~N
The device and packaged product of the present invention work on the principle of a "closed distribution system". By "closed distribution system"
it is meant herein that av membrane is saturated with a liquid and that air is prevented ~5 frorn entering the aystem even under vacuum, provided the vacuum pressure does not exceed the bubble point pressure of the membrane. Liquid can then be drawn across the membrane out of the closed distribution system, for example by internal pressure or external suction. internal pressure may be generated for example by squeezably deforming the reservoir. External suction may be 20 generated, for exarnpie in the case of a drinking bottle, by sucking at the outlet.
External suction m:ay also be generated by the adhesion force of the surface to which the liquid is applied, for example in the case of the skin that is absorbing a IOtion.
25 However liquid will not be dispensed (i.e. will not spill or drip) from the reservoir even if the outlet is oriented below the surface of the liquid provided the pressure due to th~~ head of liquid does not exceed the bubble point pressure of the saturated membrane. In such circumstances air from the external atmosphere is unable to enter the closed distribution system, and consequently 30 liquid does not leave the closed distribution system.

WO 00100406 PCTIUS99l14645 The term "fluid" as defined herein comprises liquid or gas.
The term "hermetically sealed" as used herein means that a gas (especially air) can neither pass from the outside environment to the inside of the reservoir;
nor from the inside of the reservoir to the outside environment, when the membrane is saturated with liquid as long as the pressure differential across the membrane does not exceed the bubble point pressure. in particular the membrane to reservoir seal, or the membrane to membrane seal prevents the ~ o leakage of gas across the sealed region.
The membrane has an average pore size of no more than 100 micrometers, preferably no more than 50 micrometers, more preferably no more than 10 micrometers, and most preferably of no more than 5 micrometers. it is also t5 preferred that the membrane has a pore size of at least 1 micrometer, preferably at least 3 micrometers. It is further preferred that the pore size distribution is such that 95% of the pores have a size of no more than 100 micrometers, preferably no more than 50 micrometers, more preferably no more than 10 micrometers, and most preferably of no more than 5 micrometers.
The membrane has an average thickness of less than 1 mm, preferably less than 100 micrometers, more preferably less than 30 micrometers, and even more preferably the membrane has an average thickness of no more than 10 micrometers, and most preferably of no more than 5 micrometers.
The term "oleophilic" as used herein refers to materials having a receding contact angle for the oily liquid to be transported of less than 90 degrees, preferably less than 70 degrees, more preferably less than 50 degrees, even more preferably less than 20 degrees, and most preferably less than 10 degrees.

The term "hydroi~hilic" as used herein refers to materials having a receding contact angle for distilled water of less than 90 degrees, preferably less than 70 degrees, more preferably less than 50 degrees, even more preferably less than 20 degrees, and most preferably less than 10 degrees.
Reservoir The term "reservoir" as used herein refers to a bulk region which holds or o stores a liquid prior to application or dispensing. In one aspect of the present invention the liquid is stored or held in the pores of a bulk material which is located in the reservoir. In an alternative aspect of the present invention the reservoir contains nc~ material other than the liquid itself. In this aspect the reservoir is defined t>y a wall region, such as may be found in a bottle or a ~5 container, for example .
A key requirement for the reservoir is to have a low average flow resistance, such as expressed by having a permeability k of at feast 10-" m2, preferably more than 10$ m2, more preferably rr~ore than 10'' m2, and most preferably more than 20 1 Or m2. In the first aspect of the present invention, high permeabiiities for the bulk materials can be achieved by utilizing material providing relatively high porosity.
Such a porosity; whi::h is commonly defined as the ratio of the volume of the materials that makes up the porous materials to the total volume of the porous materials, and as determined via density measurements commonly known, 2s should be at least 50e%, preferably at least 80%, more preferably at least 90%, or even exceeding 98%, or 99%.
In the second aapect of the present invention the bulk material essentially consisting of a single pore, or void space, the porosity approaches or even 3o reaches 100%. In this. case the bulk region is a liquid reservoir such as a bottle or some other type of container which is defined by a wail region, and the volume of the liquid reservoir is variable. Preferably the volume is varied either by flexibly deforming the wall region, or by the action of a piston.
When present the bulk material can have pores which are larger than about 200 Vim, 500 Vim, 1 mm or even 9 mm in diameter or more. Such pores may be smaller prior to the fluid transport, such that the bulk material may have a smaller volume, and expand just prior or at the liquid contact. Preferably, if such pores are compressed or collapsed, they should be able to expand by a volumetric expansion factor of at least 5, preferably more than 10. Such an expansion can be achieved by materials having an elastic modulus of more than the external pressure which, however, must be smaller than the bubble point pressure. High porosities can be achieved by a number of materials, well known in the art as such. For example fibrous members can readily achieve such porosity values.
~5 Non-limiting examples for such fibrous materials that can be comprised in the bulk region are high-loft non-wovens, e.g., made from polyolefin or polyester fibers as used in the hygienic article field, or car industry, or for upholstery or HVAC industry. Other examples comprise fiber webs made from cellulosic fibers.
2o Such porosities can further be achieved by porous, open celled foam structures, such as, without intending any limitation, for example polyurethane reticulated foams, cellulose sponges, or open cell foams as made by the High Internal Phase Emulsion Polymerization process (HIPE foams), all well known from a variety of industrial applications such as filtering technology, upholstery, 25 hygiene and so on. Such porosities can be achieved by wall regions which circumscribe voids defining the bulk material, such as exemplified by pipes.
Alternatively, several smaller pipes can be bundled. Such porosities can further be achieved by "space holders", such as springs, spacer, particulate material, corrugated structures and the Pike. The bulk material pore sizes or permeabilities 30 can be homogeneous throughout the bulk material, or can be inhomogeneous.

The bulk materi<31 can have various forms or shapes. The bulk material can be cylindrical, ellipsoidal, sheet like, stripe like, or can have any irregular shape.
The bulk material can have constant cross-sectional area, with constant or varying cross-sectional shape, like rectangular, triangular, circular, elliptical, or irregular.
The absolute si~:e of the bulk material should be selected to suitably match the geometric requirements of fhe intended use. Generally, it will be desirable to o have the minimum dimension for the intended use. The benefit of the designs according to the present invention is to allow much smaller cross-sectional areas than conventional materials. The dimensions of the bulk material are determined by the permeability oi~ said bulk material, which can be very high, due to possible large pores, as the bulk material does not have to be designed under the ~s contradicting requirernents of high flux (i.e. large pores) and high vertical liquid transport (i.e. small pores). Such large permeabilities allow much smaller cross-sections, and hence very different designs.
The bulk material can be essentially non-deformable, i.e. maintains its 2o shape, form, volume under the normal conditions of the intended use.
However, in many uses, it will be desirable, that the bulk material is soft and pliable. The bulk material can change its shape, such as under deforming forces or pressures during use, or under the influence of the fluid itself. The deformability or absence thereof can be achieved by selection of one or more materials as the bulk 25 material (such as a fibrous member).
The confining separations of the bulk material may further comprise materials which signi~fcantly change their properties upon wetting, or which even may dissolve upon wetting. Thus, the bulk material may comprise an open cell 3o foam material having a relatively small pore at least partially being made of soluble material. such as pofyvinylalcohol or the like. The small porosity can draw in liquid at the initial phase of liquid transport, and then rapidly dissolve so as to then leave large voids filled with liquid. Alternatively, such materials may fail larger pores, completely or partially. For example, the bulk material can comprise soluble materials, such as poly{vinyl) alcohol or polyvinyl) acetate.
Membrane The term 'membrane" as used herein is generally defined as a material or region that is permeable for liquid, gas or a suspension of particles in a liquid or gas. The membrane may for example comprise a microporous region to provide liquid permeability through the capilliaries. Microporous hydrophobic membranes will typically allow gas to permeate, while water-based liquids will not be ~5 transported through the membrane if the driving pressure is below a threshold pressure commonly referred to as "breakthrough" or "bridging" pressure. In contrast, hydrophilic microporous membranes will transport water based liquids.
Once wetted, however, gases (e.g. air) will essentially not pass through the membrane if the driving pressure is below a threshold pressure commonly 2o referred to as °bubble point pressure". Hydrophilic monolithic films will typically allow water vapour to permeate, while gas will not be transported rapidly through the membrane. Similarly membranes can also be used for non-water based liquids such as oils. For example most hydrophobic materials will be in fact oleophilic: A hydrophobic but oleophilic microporous membrane will therefore be 25 permeable for oil but not for water.
Membranes are often produced as thin sheets, and they can be used atone or in combination with a support layer (e.g. a nonwoven) or in a support element (e.g. a spiral holder). Other forms of membranes include but are not limited to polymeric thin layers directly coated onto another material, bags corrugated sheets.
Further known membrarfes are "activatable" or "switchable" membranes that can change thein,~ properties after activation or in response to a stimulus. This change in properties might be permanent or reversible depending on the specific use. For example, a hydrophobic microporous layer may be coated with a thin dissolvable layer e.g. made from polyvinyl}alcohol. Such a double layer system will be impermeable to gas. However, once wetted and the poly(vinyl)alcohol film has been dissolved, the system will be permeable for gas but still impermeable for liquid. Conversely, if a hydrophilic membrane is coated by such a soluble layer, it might became activated upon liquid contact to allow liquid to pass through, but not air.
~5 Another useful membrane parameter is the permeability to thickness ratio, which in the context of the present invention is referred to as "membrane conductivity". This reflects the fact that, for a given driving force, the amount of liquid penetrating through a material such as a membrane is on one side proportional to the ~>ermeability of the material, i.e. the higher the permeability, 2o the more liquid will penetrate, and on the other side inversely proportional to the thickness of the material. E~~ence, a material having a lower permeability compared to the same material having a decrease in thickness, shows that thickness can compensate fos~ this permeability deficiency (when regarding high rates as being desirable). Typical kld for packaged products or devices according 25 to the present invention is from about 1 x 70'9 to about 500 x 10-9 m, preferably from about 100 x 10-9 to about 500 x 10-9 m. Preferably the k/d is at least 1 x 10'' and more preferably at least 1 x 10-5 m.
For a porous membrane to be functional once wetted (permeable for liquid, 3o not-permeable for air), at least a continuous layer of pores of the membrane always need to be filled with liquid and not with gas or air. Therefore evaporation of the liquid from the membrane pores must be minimized, either by a decrease of the vapour pressure in the liquid or by an increase in the vapour pressure of the air.

The evaporation prior to use of the liquid from the packaged product can also be minimised by a vapour tight cap or by completely wrapping the packaged product, for example in the case of a sponge, into a film. A suitable film may be made from various materials, for example polyethylene.

The present invention is useful as a liquid applicator or dispenser.
Examples of liquids which may be applied or dispensed using the packaged product or device of the present include: paint, glue, shoe polish, health and beauty care lotions, detergent compositions and various food and beverage ~5 products. In particular, for beverage products, the present invention may be designed for use as a drinking bottle. Other specific examples include paint applicators wherein a packaged paint product is dispensed, optionally via an applicator such as a brush or roller; skin creams or lotions, including cosmetics (such as lipsticks and nail varnishes) and pharmaceutical compositions, to be 2o applied to the body; detergent solutions for cleaning hard surfaces such as work surfaces, windows and floors. In the fatter case, the device of the present invention can be integrated into a floor mop.
25 Test method: Bubble Point Pressure (membrane) The following procedure applies when it is desired to asses the bubble point pressure of a membrane.
3o First, the membrane material is connected with a plastic funnel (available from Fischer Scientific in Nidderau, Germany, catalog number fi25 617 20) and a length of tube. The fmnnel and tlhe tube are connected in an air tight way.
Sealing can be made with F'arafilm M (available from I=lecher Scientific in Nidderau, Germany, catalog number 617 800 02). A circular piece of membrane material, slightly larger than thE: open area of the funnel, is sealed in an air tight way with the funnel. Sealing is made with suitable adhesive, e.g. Pattex from Henkel KGA, Germany). The lower end of the tube is left open i.e. not covered by a membrane material. The tube sh;ouid be of sufficient length, i.e. up to 10m length may be required.
In case the tesl: material is very thin, or fragile, it can be appropriate to support it by a very open support structure (as e.g. a layer of open pare non-woven material) before connecting it with the funnel and the tube. In case the test specimen is not of sufficient size, the funnei may be replaced by a smaller one (e.g. Catalog # X326 616 02 from Fisher Scientific in Nidderau). If the test specimen is too large size, a representative piece can be cut out so as to fit the funnel.
The testing liquid can be the transported liquid (i.e. oil or grease), but for ease of comparison, the testinc,~ liquid should a sblution 0.03% TRITON X-100, 2o such as available from MERCK KGaA, Darmstadt, Germany, under the catalog number 1.086039 in distilled or deionized water, thus resulting in a surface tension of 33 mNlm.
Whilst keeping 'the lower (open) end of the funnel within the liquid in the reservoir, the part of the funnel with the membrane is taken out of the liquid. if appropriate, but not necessarily, the funnel with the membrane material should remain horizontally aligned.
Whilst slowly continuing to raise the membrane above the reservoir, the 3o height is monitored, and it is carefully observed through the funnel or through the membrane itself (optionally aided by appropriate lighting) if air bubbles start to enter through the material into the inner of the funnel. At this point, the height above the reservoir is registered to be the bubble point height.
From this height H the Bubble point pressure BPP is calculated as:
BPP = p ~ g ~ H with the liquid density p, gravity constant g ( g ~ 9.81 mls2).
in particular for bubble point pressures exceeding about 50 kPa, an alternative determination can be used, such as commonly used for assessing bubble point pressures for membranes used in filtration systems. Therein, the membrane is separating two liquid filled chambers, when one is set under an increased gas pressure (such as an air pressure), and the point is registered when the first air bubbles "break through".
't 5 Determination of Pore Size Optical determination of pore size is especially used for thin layers of porous system by using standard image analysis procedures known to the.
ski4led_ 2o person.
The principle of the method consists of the following steps: 1 ) A thin layer of the sample material is prepared by either slicing a thick sample into thinner sheets or if the sample itself is thin by using it directly. The term "thin"
refers to 25 achieving a sample caliper low enough to allow a clear cross-section image under the microscope. Typical sample calipers are below 200Nm. 2) A
microscopic image is obtained via a video microscope using the appropriate magnification. Best results are obtained if about 10 to 100 pores are visible on said image. The image is then digitized by a standard image analysis package 3o such as OPTIMAS by BioScan Corp. which runs under Windows 95 on a typical IBM compatible PC. Frame grabber of sufficient pixel resolution (preferred at least 1024 x 1024 pixels) should be used to obtain good results. 3) The image is converted to a binaryr image a sing an appropriate fihreshold level such that the pores visible on the image arE~ marked as object areas in white and the rest remains black. Automatic threshold setting procedures such as available under OPTIMAS can be used. 4) Z'he areas of the individual pores (objects) are determined. OPTIMAS offers fully automatic determination of the areas. 5) The equivalent radius for each pore is determined by a circle that would have the same area as the pore. If A is i:he area of the pore, then the equivalent radius is given by r=(Al~)'r. The average pore size can then be determined from the pore o size distribution using standard statistical rules. For materials that have a not very uniform pore size it is recommended to use at least 3 samples for the determination.
Optionally comnnercially available test equipment such as a Capillary Flow 1 s Porometer with a pressure range of 0-1380 kPa (0-200psi), such as supplied by Porous Materials, Inc, Ithaca, Jew York, US model no. CFP-1200AEXi, such as further described in respective user manual of 2197, can also be used to determine bubble point pressurae, pore size and pore size distribution.
Determinations of call&~
The caliper of trEe wet sample is measured (if necessary after a stabilization time of 30 seconds;) under the desired compression pressure for which the experiment will be run by using a conventional caliper gauge (such as supplied by AMES, Waitham, MASS, US) having a pressure foot diameter of 1 1I8 "
(about 2.86 cm), exerting a pressure of 0.2 psi (about 1.4 kPa) on the sample, unless otherwise desired.

Determination of ~ermeabiliy and conductivi~r Permeability and conductivity are conveniently measured on commerciafky available test equipment.
For example, equipment is commercially available as a Permeameter such as supplied by Porous Materials, Inc, Ithaca, New York, US under the designation PM! Liquid Permeameter. This equipment includes two Stainless Steel Frits as porous screens, also specified in said brochure. The equipment ~o consists of the sample cell, inlet reservoir, outlet reservoir, and waste reservoir and respective filling and emptying valves and connections, an electronic scale, and a computerized monitoring and valve control unit. A detailed explanation of-a suitable test method using this equipment is also given in the applicants co pending application PCT/US98113497, filed on 29~' June 1998 (attorney docket no. CM1841FQ).
Exams 2o Example 1 A sponge comprises a polyurethane bulk material completely surrounded by a polyamide membrane. The membrane was sealed to itself at both ends of the sponge, as well as along the length of the sponge so that all fluid passing into or out of the sponge must pass through the membrane. The membrane had an average pore size of 20 micrometers, an open area of 14%, a caliper of 55 micrometers and was manufactured by Sefar Inc., of Ruschlikon, Switzerland, number 03-20/14. The bulk material which is 100 mm tong, 90 mm wide and 5 mm deep, it had 10 pores per inch, and was manufactured by Kureta of 3o Stadtallendorf, Germany (K-S ppi 10).

The sponge was soaked in water so that all of the membrane was wetted.
Little or no water drips out of the .sponge, however water is transferred to the skin when the sponge is rubbed on the arm.

Example 2 A sponge comprises a polyurethane bulk material completely surrounded by 1o a polyamide membrave. The membrane was sealed to itself at both ends of the sponge, as well as along the length of the sponge so that ail fluid passing into or out of the sponge must pass through the membrane. The membrane had a~
average pore size of 20 micrometers, an open area of 14%, and was manufactured by Verseidag-Techfab of Geldern IMaldeck, Germany under the ~ trade name ivlonodur PA20. The bulk material which is 100 mm long, 90 rnm wide and 5 mm deep, it had 10 pores per inch, and was manufactured by Recticel of Westfalen, Belgium under the name Tn1110.
The sponge w~~s soaked in Nivea Body (~PIiIkT"" sold by Beiersdorf of 2o Hamburg, Germany ;~o that all of the membrane was wetted. Little or no liquid drips out of the sponge, however liquid is transferred to the skirl when the sponge is rubbed on the arm.
Example 3 A sponge comprises a polyurethane bulk material completely surrounded by a polyamide membrane. The membrane was sealed to itself at both ends of the sponge, as well as allong the length of the sponge so that all fluid passing into or out of the sponge must pass through the membrane. The following membranes were used:
(i) 03-50137 having an average pore size of 50 micrometers, an open area of 37%, a caliper of 50 micrometers;
(ii) 03-511 having an average pore size of 5 micrometers, an open area of 1 %, a caliper of 75 micrometers;
(iii) 03-10/2 having an average pore size of 10 micrometers, an open area of 2%, a caliper of 45 micrometers;
(iv) 03-20!14 having an average pore size of 20 micrometers, an open area of 14%, a caliper of 55 micrometers;
all of which are manufactured by Sefar Inc., of Ruschlikon, Switzerland.
The bulk material which was 100 mm long, 90 mm wide and 5 mm deep, it had 10 pores per inch, and was manufactured by Kureta of Stadtallendorf, ~s Germany (K-S ppi 10).
The sponge was soaked in Nivea Body MilkT"" sold by Beiersdorf of Hamburg, Germany so that alf of the membrane was wetted. little or no liquid drips out of the sponge, however liquid is transferred to the skin when the 2o sponge is rubbed on the arm.
It was found that the different membranes used in Example 3 provided a different thickness of liquid. The 03-5/1 membrane resulted in a liquid thickness of 40 micrometers; the 03-10/2 membrane resulted in a liquid thickness of 34 25 micrometers; and the 03-20114 membrane resulted in a liquid thickness of micrometers.
Example 4 WO 00/00406 PCT/US99l14645 An elastomeric structure was made out of than large pore mesh having a pore size of 5mm forming a void and giving volume for 250 m! fluid. The structure is completely surrounded by a polyamide membrane so that fluid passing into or out of the void must pass through the membrane. The membrane is sealed to itself at both ends of the mesh, as well as along the length of the mesh. The membrane had a porE~ size of 20 micrometers, an open area of 14%, a caliper of 5~ micrometers and is manufactured by Sefar Inc. of Ruschlikon, Switzerland under the product code 03-20/14.
o The membrane is wetted and the structure compressed, it remains in its compressed state. Once the membrane comes into contact with liquid, the elastic forces relax and liquid is absorbed rapidBy into the sponge.
5 Example ~
A membrane w,as hermetically sealed over the opening of a bottle of Mr Proper, 500 ml, manufactured by Procter & Gamble. The membrane was made of poiyamide, had a pore size of 5 micrometers, an open area of 1 %, a caliper of 20 75 micrometers and is manufactured by Sefar Inc. of Ruschlikon, Switzerland under the product code 03-5/1.
Once the membrane was. wetted the bottle can be held upside down and little or no cleaning liquid will drip out of the /bottle. However, liquid was 25 dispensed rapidly when the bottle was compressed manually. When the bottle was released again, the elasticity of the bottle itself re-expanded the bottle allowing the inner pressure to rise without drying the membrane.
3o Example fi WO 00/00406 PCTlUS99/14645 Use baby drinking bottle NUK bottle MAPA GmbH Gummi- & Plastikwerke, Postfach 1280, D-27392 Zeven, Germany with a Learner's spout. The membrane was hermetically seated to the opening of the bottle. The membrane was made of polyamide had a pore size of 20 micrometers, an open area of 14%, a caliper of 55 micrometers. It was manufactured by Sefar Inc. of Ruschlikon, Switzerland under the product code 03-20/14.
Once the membrane was wetted the bottle can be held upside dowh and little or no liquid will drip out of the bottle, however, the baby can drink easily out of the bottle. Once the inner pressure gets below the bubble point pressure, air wilt transfer through the membrane allowing the inner pressure to rise again.
The membrane remained wet and the bottle fully functional.

Claims (11)

19

1. A packaged product for dispensing a liquid, comprising a liquid-containing reservoir and a porous membrane, the reservoir comprising an outlet, characterised in that the membrane is hermetically sealed to or around the reservoir so that fluid passing through the outlet must pass across the membrane, and in that the combination of the liquid and the membrane results in a bubble point greater than 1 kPa, when measured at ambient temperature and pressure using the packaged liquid.

2. A packaged product according to claim 1 wherein the bubble point pressure is greater than 2 kPa.

3. A packaged product according to either claim 1 or 2 wherein the membrane is flexible.

4. A device for dispensing a liquid, comprising a liquid reservoir and a porous membrane, the reservoir comprising an outlet, characterised in that the membrane is hermetically sealed to or around the reservoir so that fluid passing through the outlet must pass across the membrane, and wherein the membrane has an average pore size of from 1 to 100 micrometers and a thickness of less than 1 mm.

5. A device according to claim 4 wherein the membrane has a pore size distribution such that 95% of the pores have a size of no more than 100 micrometers.

6. A device according to claim 4 wherein the membrane has a bubble point pressure of at least 1 kPa, preferably at least 2kPa, when measured with 0.03% solution of Triton X-100 in distilled water as the standard test liquid.

7. A device according to claim 4 wherein the device is for dispensing an aqueous liquid, wherein the membrane is hydrophilic, and wherein the membrane has a bubble point pressure of at least 1 kPa, preferably at least 2kPa, when measured with distilled water.

8. A device according to any of claims 4 to 7 wherein the membrane is flexible.

9. A device according to any of claims 4 to 8 wherein the reservoir comprises a bulk material, preferably wherein the bulk material is elastic.

10. A device according to claim 4 wherein the reservoir is a bottle.

11. A device according to any of claims 4 to 10, wherein the membrane is a woven mesh or apertured film.