Foaming Bottom-Dispensing Containers

The present invention relates to foaming bottom-dispensing containers.

Foaming is seen by many users as an indication of cleaning efficacy of the detergent composition. As such, foaming detergents have gained popularity due to their ability to generate a rich, stable foam that adheres to surfaces and enhances cleaning performance. Foaming detergents are especially preferred for applications such as dishwashing, where the foam helps to suspend and lift away food residues and grease, shampoos, where the foam helps to lift dirt and grease from hair as well as reduce tangling, and shaving foams, where the foam creates a protective barrier of lather over the hair to make them soft before the razor runs through it. However, the existing packaging options for liquid detergents have limited capabilities in generating and maintaining foam during dispensing.

Liquid detergent compositions are commonly used in various household cleaning applications, including dishwashing, laundry, and surface cleaning, and for personal cleansing, including body washes, shampoos, and shaving. Traditionally, when foaming is desired, these liquid detergents have been dispensed using pressurised containers or packages comprising a foaming pump dispenser. While these packaging methods effectively deliver the liquid detergent, they suffer from reduced dispensing and foaming as the propellant is used up, or over-dispensing due to the pump-action of the foaming pump dispenser. Moreover, there is often a need to further lather up the detergent composition to provide the desired foam.

Various attempts have been made to develop packaging solutions that enable the controlled dispensing of detergent foam. Some prior art discloses the use of specialized foaming pumps or aerosol cans to generate foam during dispensing, using an incorporated propellant or compressed air. While effective, these packaging solutions often require complex mechanisms or propellant gases, making them expensive and less environmentally friendly. Moreover, such foamers are top-dispensing as they require air to enter the foaming mechanism, and be combined with the liquid detergent composition in order to form the foam. Some of these packaging executions can deliver foam after inverting so that the foam-dispensing head is oriented below the container. However, such containers have to be regularly reoriented with the dispensing head repositioned above-the container, so that the foaming mechanism is resupplied with air. This is typically the case for both pressurised foaming containers and pump-action foam dispensers. A further challenge for foam dispensing packages is that if the user squeezes slowly, liquid with little foam is dispensed.

Bottom-dispensing foamers are known, but generally require that the container is kept in an upright orientation for a period of time after each dispensing, in order to replenish the air in the foaming mechanism. The need for manual rotation to the upright orientation after each dispensing cycle hinders repetitive dispensing and is not desirable during use. If such containers are not inverted to replenish the air in the foamer mechanism, no foam is produced. Moreover, leakage from such bottom-dispensing foamers remains challenging. This is especially challenging since a low liquid viscosity is preferred in order to provide good foaming. While leakage can be addressed through attachment of a closing cap to the bottom dispensing container, such closing caps are not convenient to consumers as they require an additional opening/closing step between dosing. Moreover, there is often a spurt of detergent composition released as the cap is opened. A further challenge for bottom-dispensing foamers is the tendency to initially dispense liquid rather than foam. This can be due to residual liquid remaining in the dispensing portion of the foaming package, or poor initial mixing of the liquid and air.

As such, there is a need for a bottom-dispensing package that offers a simple, cost-effective, and user-friendly solution for dispensing liquid detergent compositions in a foamed state from the bottom of the package, while being maintained in a bottom-dispensing orientation and without the need to invert the container for the air reservoir to be replenished. There also remains a need for such bottom-dispensing foaming packages to provide improved foaming, especially initial foaming during use.

Furthermore, there is a need for such containers to be resistant to leakage, even when there is no closing cap. The package should also provide dosing of different amounts of foamed detergent composition in a controlled manner.

WO2019216272 A1 relates to a foam discharge container that is suitable for both prevention of dripping and stable discharge of foam in a preferable quality. The foam discharge container is provided with: a container body; a cap to be attached to an opening of the container body; and a valve for opening and closing a flow channel in the cap. The cap has: a liquid material flow channel that provides passage for a liquid material within the container body; an air flow channel that provides passage for air within the container body; a mixing chamber that is connected with these two types of flow channels while the valve is in an open state; and a cap opening that is connected with the outside of the container. The valve comprises: a cylindrical fixed ring which is fixed to the cap at a position that surrounds the respective exits of the two types of flow channels; and an inner valve which is formed inside the fixed ring and which is elastically deformable and capable of simultaneously opening/closing the respective exits of the two types of flow channels. The inner valve, in a closed state, is a membrane which is formed so as to lie from the cylindrical portion of the fixed ring toward a central axis thereof and simultaneously to be slanted toward the container body side. U.S. Pat. No. 5,213,236 relates to a dispensing package for fluid products such as liquid soaps, shampoos and conditioners, household detergents, cleaners, polishes, moisturizing creams, and the like, and includes a container with a self-scaling dispensing valve mounted therein. The valve includes a marginal flange, a valve head with a discharge orifice therein, and a connector sleeve () having one end connected with the valve flange and the opposite end connected with the valve head adjacent a marginal edge thereof. The connector sleeve () has a resiliently flexible construction, such that when pressure within the container raises above a predetermined amount, the valve head shifts outwardly in a manner which causes the connector sleeve () to double over and extend rollingly. DE10122557A1 relates to a device on the removal hole which prevents the product dripping out after wall pressure by hands is released. The device contains slit segments in one plane and as many slit segments in a second plane, respective plane segments being positioned so the bottom edges of the first segments make contact with the top edges of the second segments in each case. Two or four segments are preferred and the container seal is by screw or snap action. Container lid and seal are hinged together and preferred segment thickness is 0.25 mm, the device diameter being 10-20 mm. CN2784322Y relates to a headstand bottle, which comprises a bottle body, a bottle cap and an outer packing cap, wherein the opening of bottle body is opened downwards; the bottle cap is fixedly connected to the lower end of the bottle body through a screw and is provided with a liquid outlet; a silica gel inner cap and an inner partition board are orderly fixed to the position between the opening of the bottle cap and the opening of the bottle body. Because the utility model has the opening opened downwards of the bottle body and adopts the silica gel inner cap and the partition board, liquid in the liquid bottle which is reversely arranged cannot flow out naturally. The utility model has the advantages of simple structure, convenient use and opening, sanitation and cleanness, application for bottles filled with little liquid, natural, convenient, and clean pouring of the liquid, and special application for loading various viscous liquid, such as liquid shampoo, cleanser essence, etc., CN1507827A relates to a wall liquid soap distributor for washroom. Said distributor adopts a bottle with a certain elasticity, said bottle can be inverted for use, its liquid outlet is smaller than mouth of general bottle, on the bottle mouth position a platform surface is formed, on the platform surface an elastic thin sheet is placed, and on the clastic thin sheet several opening and closing seams are set, a bottle cap whose inner wall has screw and whose center has a circular hole can be tightly screw-turned on the bottle body and can be used for tightly pressing the opening and closing scams. Said invention is simple in structure, low in cost, and also provides its application method. EP3492400 relates to a liquid dispenser for dispensing liquid from an inverted container. The dispenser comprises a body, a valve and an impact resistance system especially adapted for absorbing transient liquid pressure increases (e.g., hydraulic hammer pressure) to substantially reduce/prevent undesirable opening of the valve and leakage of the liquid.

JP6904879B relates to a squeeze foamer container that foams and discharges the content liquid contained in the container body by squeezing the container body. The squeeze foamer container described therein is designed to solve the problem that even before squeezing the container body, if the container body is tilted and the discharge port is directed downward, the content liquid may drip from the discharge port. In addition, at the end of discharge after squeezing the container body, the content liquid was not drained well. In the squeeze former container described therein, when the body of the container body is squeezed (squeezed) with the container body tilted and the discharge port facing downward, the liquid contained in the container body is pressurized and then passes through the mixing member. When the container is tilted, the air in the container body moves to the vicinity of the dip-tube entrance and is also pressurised when the container body is squeezed, such that the air passes through the dip-tube and into the mixing member. The air and liquid are then combined in the mixing member before entering the foaming member such as a mesh or sponge (porous body), and through a slit valve provided at the discharge port which is elastically deformed by the pressure of the liquid. The squeeze foamer container described therein does not comprise an air inlet valve which is a one-way valve for allowing ingress of air into the mixing chamber through the dip-tube, while preventing air and residual foam or liquid entering into the dip-tube from the mixing chamber after the squeezing pressure is released. As such, when the squeezing pressure is released, foam can build up within dip-tube resulting in poor foam dispensing during subsequent dosing, especially when the container is left inverted in a bottom-dispensing orientation. In addition, the lack of the one-way valve at the entry from the dip-tube to the mixing chamber results in the liquid filling the mixing chamber if the container is left inverted in a bottom-dispensing orientation. As a result, liquid is dispensed during the subsequent dosing, instead of foam, especially if the container is not capped. As such, it is necessary for the containers of JP6904879B2 to be returned to an upright orientation after dispensing. US20020153389A relates to a foam dispenser which includes a resiliently deformable bottle which has an interior, a neck at one end thereof and an opposed end. The bottle has an at rest position and an under pressure position. A mixing chamber is proximate to the neck and has a soap inlet and an air inlet both upstream of an outlet. The outlet has a porous material thereover. The interior of the bottle is in flow communication with the mixing chamber through the soap inlet. An air tube extends from the mixing chamber into the interior of the bottle and has a distal end proximate to the opposed end of the bottle whereby the mixing chamber is also in flow communication with the interior of the bottle through the air tube. A self sealing pressure actuated valve is for selectively opening and closing the outlet and is responsive to pressure applied to the bottle. The self sealing pressure actuated valve is closed via a metal spring. Such springs require a relatively high pressure to actuate. WO9114648A1 relates to foamable liquid dispensers of the type where foamable liquid and air are mixed, the foamer includes a squeeze bottle and a device for simultaneously restricting flow of the compressible fluid and incompressible fluid until a predetermined threshold pressure is developed within the bottle by manual deformation thereof, thus foam is not dispensed from the bottle until a pressure is developed within the bottle sufficient to produce a desirable foam.

The present invention, in an example, relates to a bottom-dispensing foam discharge package (), wherein the bottom-dispensing foam discharge package comprises: a resiliently squeezable container () for housing a liquid composition, the resiliently squeezable container () comprising a container wall (); a void volume (); a base () operably connected to said container (), wherein the base () comprises a base orifice (); and a foamer body (), wherein the foamer body () comprises: a mixing chamber (); at least one liquid inlet (); at least one air inlet (), wherein the at least one air inlet () comprises: an air inlet valve (), wherein the air inlet valve () is a one-way valve which allows ingress of air into the mixing chamber () from the void volume () through the air inlet (), and the air inlet valve () opens at a pressure differential of from 1.0 to 25 mbar, measured at 20° C.; and a foam outlet () operably connected to the base orifice (), wherein the foam outlet () comprises a foam-dispensing valve () for dispensing the foam from the mixing chamber () through the foam outlet (), and the foam-dispensing valve () opens to dispense foam at a pressure differential of from 25 to 250 mbar, measured at 20° C.

The foaming body () is connected to a dip-tube (). The inset toshows a cut away view of part of the container wall () of the embodiment of, showing the grooves (), and the groove top () and the groove bottom (), as well as the exterior surface (). The inset also shows the pitch () between adjacent grooves.

Incorporating a foamer body, as described herein, into the base of a bottom dispensing package, results in a bottom-dispensing package that dispenses varying amounts of liquid compositions in a foamed state from the bottom of the package in a controlled manner, while being able to be kept for long durations in a bottom-dispensing orientation and without the need to invert the container for the air reservoir to be replenished, while also being resistant to leakage, even when there is no closing cap. Additionally, the foaming bottom-dispensing containers described herein can be maintained in their bottom-dispensing orientation while minimizing the amount of the liquid composition that is dispensed in a non-foamed state. This is because the entry of the liquid into the mixing chamber, before the entry of the air from the void volume, is significantly reduced, in comparison to prior foam dispensing packages, such as those described in US20020153389A. Moreover, the design of the foamer body ensures that air is drawn through the foamer body upon release of the squeezing force applied during dispensing. This both reduces leakage while the package is being stored, and reduces the amount of unfoamed liquid that is dispensed during subsequent use, since less liquid remains in the foamer body. This is in contrast to prior art foaming packages such as WO9114648A1, in which air is drawn through the dip-tube directly from the atmosphere, when the squeezing pressure is removed.

By resiliently squeezable, what is meant is that the container wall () exhibits a degree of flexibility sufficient to permit deformation in response to manual forces applied to the outer surface of the container wall () and a degree of resilience sufficient to return automatically to its undeformed condition when said manually applied forces are removed from the outer surface of the container wall (). By the terms “a” and “an” when describing a particular element, we herein mean “at least one” of that particular element. The term “dose” as used herein is defined as the measured amount of liquid to be delivered by the package. The dose begins when the liquid first exits the base orifice () and ends once the flow of said liquid stops. By “substantially independently from pressure” as used herein it is meant that pressure causes less than 10% variation from the target measured dose. By “substantially constant liquid output or dosage” as used herein it is meant that variation from the target measured dose is less than 10%. By “shear thinning” as used herein it is meant that the liquid referred to is non-Newtonian and preferably has a viscosity that changes with changes in shear rate. By “drip-free” as used herein it is meant that no visible residue is left proximal to the nozzle of the cap following dosing and/or that no liquid exits the resilient container without squeezing.

A preferred field of use is that of dosage devices for domestic or household use, containing detergents such as hard surface cleaning compositions, liquid laundry detergent compositions, or other cleaning preparations, and the like. A particularly preferred field of use is hard surface cleaning, especially manual dishwashing. For such applications, the resiliently squeezable container () can have an overflow volume, as measured using the method described herein, of from 0.1 litres to 5 litres, preferably from 0.2 litres to 1.5 litres, more preferably from 0.25 litres to 0.75 litres. The volume of liquid dosed for each squeeze of the package () is typically from 1 ml to 50 ml, preferably from 2 ml to 30 ml, more preferably 3 ml to 20 ml.

The invention is directed to a package () for repeatedly dosing a quantity of liquid. The package () comprises a resiliently squeezable container (), and a base () operably connected to said container ().

Bottom-dispensing packages () have several advantages over other packaging types. The package () does not need to be inverted, requiring fewer user motions for dispensing and providing greater positioning and dispensing control than for packages that dispense from orifices in the top of the package. In addition, there is no need to wait for the liquid contained within to reach the orifice before dispensing, especially when the amount of composition remaining within the package is low. Thus bottom-dispensing packages simplify activities such as hand dishwashing, where repeated dosing of detergent composition is required.

A significant advantage of the present bottom dispensing package () is its non-pressurized nature. That is, the liquid contained within the resiliently squeezable container is not maintained under a pressurised gas or similar means. By eliminating the need for pressurized components, the bottom dispensing package () can be manufactured at a relatively lower cost compared to pressurized alternatives. Furthermore, the absence of pressurization in the package () results in enhanced flow rates during extended periods of use. The liquid can be dispensed smoothly and consistently, maintaining its desired properties without experiencing a decline in performance over time. This ensures a reliable and satisfying user experience.

The resiliently squeezable container () is preferably a bottle. The resiliently squeezable container () comprises a container wall ().

The resiliently squeezable container () can comprise a container opening (), wherein the container opening () is positioned at a lower portion or at the bottom of the container ().

The resiliently squeezable container () can have an internal volume, for the liquid contained therein, of from 0.1 litres to 5.0 litres, preferably from 0.2 litres to 1.5 litres, more preferably from 0.25 litres to 0.75 litres.

That container () can have a height of from 75 mm to 300 mm, preferably from 100 ml to 270 ml, more preferably from 150 mm to 225 mm, wherein the height of the container is measured from the inner-surface of the orifice () which is within the bottom-dispensing package (), to the top of the container () or, if a cap () is present, to the top of the cap ().

The container wall () can have a thickness of from 0.25 mm to 8.0 mm, preferably from 0.5 mm to 6.0 mm, more preferably from 1.0 to 4.0 mm.

The top of the container (), distal from the base (), can be closed. Alternatively, the container can comprise a cap (), the cap () preferably being detachable. If present, the cap () can be comprised on the top of the container, distal from the base (). Such caps () can be sized to provide easy refilling of the container () without the need to remove the base (). The cap () can be a screw-on cap, or a push-fit cap or other form of cap which sealingly engages with the container ().

Especially, but not only, when the container wall () is at least partially made from an elastomer, the container wall () can be very flexible. As such, if needed, the cap () can comprise an attachment ring which is fixedly attached to the container wall (), for instance via gluing or welding. Alternatively, the container wall () can be moulded on to the cap (), or vice-versa. The cap () can be permanently attached to the enclosure, for instance, via a string or plastic chord, or may be fully detachable. The cap (), and if present its attachment ring is preferably rigid.

The interior () or exterior surface () of the resiliently squeezable container () can comprise at least one, preferably multiple, circumferentially oriented grooves (). Such grooves () on the interior surface result in greater flexibility and spring-back of the container while ensuring that the exterior surface () can be left smooth or textured as desired. In addition, the exterior surface () of the container () remains easy to clean. The at least one groove () is preferably essentially horizontally oriented. As such, the groove () can have a spiral form or can be one or more horizontal groove (). Multiple horizontal grooves () are preferred.

The at least one circumferentially oriented groove () can extend over at least 70%, preferably at least 80%, more preferably at least 95%, most preferably 100% of the circumferential length of the interior surface () of the container wall () where the at least one circumferentially oriented groove () is positioned. The interior surface () of the container wall () preferably comprises multiple circumferentially oriented grooves (). The circumferentially oriented grooves () can be present over a groove zone () which extends over at least 25%, preferably at least 50%, more preferably at least 75% of the height of the container wall ().

Where the circumferentially oriented grooves () are present, the grooves () can be spaced out such that the pitch () is from less than 1 mm to 15 mm, preferably from 2 mm to 12 mm, more preferably from 2.5 mm to 10 mm, wherein the pitch () is defined as the distance between two adjacent peaks () of the circumferentially oriented grooves () on the interior surface () of the resiliently squeezable container.

If grooves () are present, the wall thickness is measured as the distance between the exterior surface () and the groove top (), measured perpendicular to the exterior surface () of the container wall ().

The exterior surface () of the container wall () can comprise further grooves or ribs. However, the exterior surface is preferably essentially free of such further grooves or ribs, with the possible exception of such further grooves and ribs which form part of a mark, such as a trademark, ingredients, or the like.

The container wall () can have a wider portion (), such that at least part of the exterior surface of the container () has a convex shape. For good gripping and dispensing, the wider portion () preferably has a radius of from 25 mm to 120 mm, preferably from 40 mm to 100 mm, more preferably from 50 mm to 80 mm. Where the cross-section of the wider portion () of the container wall () is non-circular, such as oval, the radius is calculated based on a circular cross-section having the same cross-sectional area. The radius of the wider portion () is calculated where the cross-sectional area is a maximum.

The container wall () can have a narrow portion (), such that at least part of the exterior surface of the container wall () has a concave shape which is narrower that the adjacent parts of the container (). The narrow portion () is preferably situated adjacent to the wider portion () of the container wall (), and in particular, adjacent to where the container wall () would typically be gripped and squeezed. In such embodiments, the narrow portion () and the wider portion () are connected together by a point of inflexion. The narrow portion () preferably has a diameter of from 30 mm to 65 mm, preferably from 35 mm to 55 mm, more preferably from 40 mm to 50 mm. Where the cross-section of the narrow portion () of the container wall () is non-circular, such as oval, the radius is calculated based on a circular cross-section having the same cross-sectional area. The radius of the narrow portion () is calculated where the cross-sectional area is a minimum. The ratio of the diameter of the wider portion () to the narrow portion () is preferably from 1.1:1 to 3:1, more preferably from 1.2:1 to 2.0:1, and most preferably from 1.3:1 to 1.7:1. The diameter of the wider portion () is measured where the diameter is largest, while the diameter of the narrow portion () is measured where the narrow portion is narrowest. For containers having a non-circular horizontal cross-section, the diameter is defined as the diameter of the circle having the same cross-sectional area. While the variation in the diameter appears relatively small, it corresponds to the ratio of the cross-sectional area of the wider portion () to the narrow portion () being preferably from 1.21:1 to 9.0:1, more preferably from 1.44:1 to 4.0:1, and most preferably from 1.69:1 to 2.89:1.

The container wall () has both a wider portion () and a narrow portion (), more preferably wherein the narrow portion () is above the wider portion (). Such containers () provide improved spring-back to the original shape once the squeezing pressure has been removed. In addition, by squeezing on the narrow portion () of the container wall (), accurate dosing of smaller amounts of the composition, contained therein, can be achieved. By squeezing on the wider portion () of the container wall (), accurate dosing of large amounts of the composition, contained therein, can be achieved.

The wider portion () and preferably both the wider portion () and the narrow portion () have either a circular or oval cross section, with a circular cross section being preferred. It has been found that such cross-sections result in improved spring-back of the container wall () back to the original shape, after the squeezing pressure has been removed. This is in contrast to stiffer bottom-dispensing containers such as those made from polyethylene terephthalate (PET), polyethylene, polypropylene, and the like, where an essentially flat front panel and preferably also a back panel are more desired.

Resin materials suitable for use in making the resiliently squeezable container (), especially the container walls (), can be selected from the group consisting of: polyethylene terephthalate (PET), polypropylene (PP), low-density polyethylene (LDPE), high-density polyethylene (HDPE) and mixtures thereof, preferably polyethylene terephthalate (PET), or high-density polyethylene (HDPE), more preferably polyethylene terephthalate (PET). Such materials are particularly suitable when forming the container () using an injection stretch blow-moulding process.

The resiliently squeezable container () formed from such resins can be made using any suitable process, though blow-moulding (BM) processes, and especially extrusion blow moulding or injection stretch blow-moulding (ISBM) processes are preferred, with injection stretch blow-moulding (ISBM) processes being most preferred.

Further details on extrusion blow-moulding can be obtained in general packaging textbook, for example in “The Wiley Encyclopaedia of Packaging Technology”, referred to above (in particular pages 83-86). Extrusion blow-moulding may be used to obtain laminated or co-extruded containers with multiple layers for aesthetic or improved physical (barrier) properties. More information on injection stretch blow-moulding processes can be obtained from general textbooks, for example “The Wiley Encyclopaedia of Packaging Technology”, Second Edition (1997), published by Wiley-Interscience Publication (in particular see pages 87-89).

The present package () can be foreseen to be durable so that it can be repeatedly refilled and re-used. Materials such as polyethylene terephthalate (PET), polyethylene, polypropylene, and the like, are prone to strain-hardening and cracking after repeated use, especially when at the thickness to provide the desired spring-back after use. Therefore, the container wall () of use in the present invention can be at least partially made from, for example, an elastomer, preferably wherein the elastomer is selected from the group consisting of: thermoplastic elastomer, silicone rubber, rubber, or a combination thereof, with thermoplastic elastomers and/or silicone rubber being preferred and thermoplastic elastomers being particularly preferred. The container wall () is preferably fully made from the elastomer, with the exception of any components that are necessary for connecting the optional cap () and/or base ().

Elastomers are polymers with viscoelasticity, generally having low Young's modulus and high yield strain compared with other materials. Elastomers are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible. As such, they are relatively soft and deformable at ambient temperatures, for instance 21° C.

Thermoplastic elastomers (TPE) are copolymers or a physical mix of polymers, such as a plastic and a rubber, which comprises materials with both thermoplastic and elastomeric properties. Thermoplastic elastomers are relatively easy to manufacture, for example, by injection molding. Thermoplastic elastomers show advantages typical of both rubbery materials and plastic materials. The principal difference between thermoset elastomers and thermoplastic elastomers is the type of crosslinking bond in their structures. The crosslink in thermoset polymers is a covalent bond, such as created during a vulcanization process. In contrast, the crosslink in thermoplastic elastomer polymers is physical, reversible, typically comprising entanglements, a weaker dipole or hydrogen bond or a difference in material phase such as crystalline regions. For example, one of the constituent polymers, or segments of the constituent polymer has a melting or glass transition temperature well above room temperature. Examples of suitable thermoplastic elastomers, methods of making them, and methods of processing that, can be found in “Handbook of Thermoplastic Elastomers”, December 2007, Drobny, ISBN 9780815515494.

Thermoplastic elastomers include reactor-made thermoplastic elastomers, such as styrene block copolymers (SBC), thermoplastic polyether block amides (TPA), thermoplastic polyurethane elastomer (TPU) and thermoplastic copolyester elastomer (TCA). Reactor-made thermoplastic elastomers are implemented in one polymer that is formed through a reaction process which results in polymer segments that provide the thermoplastic properties and polymer segments that provide the elastomeric properties. Other thermoplastic elastomers comprise a blend of polymers, such as homopolymers and/or copolymers, that give rise to crystalline domains where blocks from the polymer co-crystallizes with blocks in adjacent chains, such as in copolyester rubbers. Depending on the block length, the domains are generally more stable than the latter owing to the higher crystal melting point. That crystal melting point determines the processing temperatures needed to shape the material, as well as the ultimate service use temperatures of the resultant thermoplastic elastomer. Such materials include Hytrel®, a polyester-polyether copolymer and Pebax®, a nylon or polyamide-polyether copolymer. Reactor-made thermoplastic elastomers are preferred, especially thermoplastic polyurethane elastomers (TPUs).

Thermoplastic elastomers, often referred to as “thermoplastic olefins” are typically derived from polyolefins and are also preferred due to their improved recyclability. The thermoplastic elastomer can contain further ingredients such as plasticizers, fillers, compatibilizers, and the like.

Silicone rubbers are elastomers composed of silicone. Silicone rubbers are often one- or two-component polymers, and may comprise fillers to improve properties or reduce cost. Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and a wide range of temperatures, while still maintaining their properties. Due to these properties and case of manufacturing and shaping, silicone rubber can be found in a wide variety of products, including voltage line insulators; automotive applications; cooking, baking, and food storage products; apparel such as undergarments, sportswear, and footwear; electronics; medical devices and implants; and in home repair and hardware, in products such as silicone sealants. Silicone is typically a highly adhesive gel or liquid, which is converted to silicone rubber by curing, such as through vulcanisation (condensation curing), catalysed curing, or peroxide curing. This is normally carried out in a two-stage process at the point of manufacture into the desired shape, and then in a prolonged post-cure process. The curing process can be accelerated by adding heat or pressure.

Suitable rubbers can be either naturally derived, or synthetically derived. Naturally derived rubber comprises suitable polymers derived from natural sources, most often isoprene with minor impurities of other organic compounds. Natural rubber is typically harvested in the form of latex. The latex is then refined into rubber ready for commercial processing. Synthetically derived rubber is an artificial elastomer, derived from petroleum byproducts, which is crosslinked via vulcanisation. Rubber can be used either alone or in combination with other materials.

The elastomer can have a Shore A (Type A) hardness of from 0 to 80, preferably 5 to 60, more preferably 10 to 40. The Shore A hardness can be measured using the method described in ISO 868:2003 (last reviewed and confirmed in 2018). The elastomer can have a tensile elongation (break), measured in the flow direction at a stretch rate of 200 mm/min at 23° C. using the method described in ISO 37:2017 (last reviewed and confirmed in 2022), of from 200% to 1000%, preferably from 250% to 750%, more preferably from 300% to 700%. The elongation at break is a characteristic value that describes the maximum percentage elongation that a tensile specimen experiences at the moment of break. It therefore describes the deformability of a material under tensile load. The elastomer can have a compression set, measured at 23° C. over 72 hours using the method described in ISO 815-1:2019, of less than 50%, preferably less than 35%, more preferably less than 20%. The compression set measures the ability of the elastomer to withstand hardening and retain their elastic properties at ambient temperatures after prolonged compression. As such, the compression set provides an indication of the ability of the elastomer to withstand physical or chemical changes which prevent the elastomer from returning to its original dimensions after release of the deforming force, or lose too much of its elasticity.

Durable container walls () or even the resiliently squeezable container () itself can be made using any suitable moulding process, such as injection moulding, rotational moulding or compression moulding.

Injection moulding is a method to obtain moulded products by injecting plastic materials molten by heat into a mould, and then cooling and solidifying them. The method is suitable for the mass production of products with complicated shapes. With injection moulding, the elastomer is first melted down so that it can be put into the injection unit. The injection unit can be a plunger, an extruder or similar. The injection unit is typically heated to above the melt temperature of the elastomer. The melted elastomer is then injected into the mould. Once injected, it can be vulcanized or cooled so that it forms the shape of the mold, creating an elastomer molded part. For thermoplastic elastomers, cooling is typically sufficient.

With transfer moulding, the elastomer is heated and not the mould. The liquid elastomer remains in a melted state until the moulding process begins. An injector, such as a plunger, pushes the elastomer into the closed mould where it forms the shape after being cooled or vulcanized. Once cooled, the mould can be opened to release the container.

Compression moulding is a method of moulding in which the moulding material, generally preheated, is first placed in an open, heated mould cavity. The mould is closed with a top force or plug member, pressure is applied to force the material into contact with all mould surfaces, while heat and pressure are maintained until the moulding material has cured. Where the process employs thermosetting resins, for instance in a partially cured stage, either in the form of granules, putty-like masses, or preforms, the process is essentially a vulcanisation process. For improved strength or resiliency, fibres can be added to the moulding material. Advanced composite thermoplastics can also be compression molded with unidirectional tapes, woven fabrics, randomly oriented fiber mat or chopped strand. The elastomer may be loaded into the mould either in the form of pellets or sheet, or the mould may be loaded from a plasticating extruder. Materials are heated above their melting points, formed and cooled. The more evenly the feed material is distributed over the mold surface, the less flow orientation occurs during the compression stage. Compression moulding can also be used to produce sandwich structures that incorporate a core material such as a honeycomb or polymer foam into the resiliently squeezable container ().

The void volume () is a space comprised within the package () and more preferably within the resiliently squeezable container (), comprising a gas, preferably air. If the liquid composition contained within the resiliently squeezable container () is susceptible to microbial contamination or oxidisation, the void volume () can be initially filled with an inert gas, such as nitrogen. During use, the volume of gas contained within the void volume () increases as air is entrained into the container ().

When the container () is squeezed, the internal pressure generated within the container () results in the void volume () being deformed, reducing the volume of the void volume (), which results in at least part of the air contained within the void volume () being expelled through the air inlet () and air inlet valve () and into the mixing chamber ().