GB2456524A

GB2456524A - Apparatus For Dispensing A Water Dispersible Substance

Info

Publication number: GB2456524A
Application number: GB0800733A
Authority: GB
Inventors: Mark Collins
Original assignee: CONCENTRATED SOLUTIONS Ltd
Current assignee: CONCENTRATED SOLUTIONS Ltd
Priority date: 2008-01-15
Filing date: 2008-01-15
Publication date: 2009-07-22
Also published as: GB0800733D0

Abstract

A dispenser for dispensing a water dispersible substance has a handle 6 and a dispensing chamber 8, the dispensing chamber 8 having a plurality of openings 4 in a wall thereof and containing one or more dosage units 16 comprising a water-swellable or water-soluble biopolymer, which polymer has encapsulated therein a water dispersible substance; the dispenser being configured such that when the dispensing chamber 8 is held in a container C containing an aqueous medium and agitated or stirred within the container C, aqueous medium therein can pass through the openings 4 in the wall of the chamber to elute the water-dispersible substance from the polymer thereby to provide a dispersion of the water dispersible substance in the aqueous medium. The water dispersible substance may be a corrosive chemical, such as an acid, alkali or bleach.

Description

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Dispenser For Dispensing A Water Dispersible Substance

This invention relates to a dispenser for dispensing a water dispersible substance. Background of the Invention

Corrosive substances such as acids and alkalis generally require special precautions when 5 being transported and cannot easily be transported using normal mail services. The fairly robust handling that they are likely to receive if transported in the normal mail means that bottles or sachets or other containers typically used for carrying liquids may be broken or ruptured thereby releasing their contents.

Summary of the Invention

10 The present invention provides a means of transporting concentrated forms of water dispersible substances in solid form in mailing containers rather than in bottles, drums and like containers. The water dispersible substance, which may be in a concentrated liquid form, is encapsulated in a protective polymer, thereby rendering it easier to package and transport using normal mailing systems. On receiving the product, the customer can form 15 an aqueous solution of the water dispersible substance by eluting the substance from the polymer encapsulant with water using a dispenser as described herein.

Accordingly, in a first aspect, the invention provides a dispenser for dispensing a water dispersible substance, the dispenser having a handle and a dispensing chamber, the dispensing chamber having a plurality of openings in a wall thereof and containing one or 20 more dosage units comprising a water-swellable or water-soluble biopolymer, which biopolymer has encapsulated therein a water dispersible substance; the dispenser being configured such that when the dispensing chamber is held in a container containing an aqueous medium and agitated or stirred within the container, the aqueous medium can ; pass through the openings in the wall of the chamber to elute the water-dispersible 25 substance from the biopolymer thereby to provide a dispersion of the water dispersible substance in the aqueous medium.

The dispenser may comprise an elongate body, an upper part of the elongate body serving as a handle and the dispensing chamber being disposed below the handle.

The dispenser may have a tubular body secured to the handle wherein the interior of the tubular body serves as the dispensing chamber. The tubular body may have, for example, a rectangular or circular cross section.

The dispensing chamber has a plurality of openings in a wall thereof. The openings may be in a side wall of the chamber, or in a base wall of the chamber, or both.

The openings will be of a size to permit free flow of aqueous medium (e.g. water) into and out of the chamber whilst retaining the dosage units. Thus, for example, the openings may be of a size in the range from 1 to 10 mm in diameter (or largest dimension where non circular), more usually 2 to 5 mm in diameter (or largest dimension).

The handle may take the form of a cap that can be replaceably removed to allow the dispensing chamber to be refilled with dosage units.

The dispenser can be provided with monitoring means for monitoring one or more physico-chemical parameters of the dispersion. For example, the dispenser can be provided with means for monitoring the pH of the dispersion or the salinity, or the levels of one or more ions such as chloride ions, or free chlorine (hypochlorite). By measuring the pH and/or other parameters, it is possible for the user to gauge the extent to which the dispersible substance has been eluted from the polymer. Thus, the user can continue to agitate or stir the dispenser in the aqueous medium until a particular required pH or other parameter is attained at which point the elution process may be adjudged complete and the dispenser removed from the container.

The monitoring means can comprise a sensor or probe located within the dispensing chamber or on an outer surface of the wall of the dispensing chamber, the sensor or probe being positioned so that when the dispenser is placed in a container containing an aqueous medium, the sensor or probe is beneath the surface of the aqueous medium.

The sensor or probe are typically linked, either by wire or wirelessly, to a display device elsewhere on or in the dispenser, for example in the handle. The display device can be an alphanumeric display or can be a simple indicator such as a light (e.g. an LED) that indicates when the physicochemical parameter being monitored has reached a desired value. Thus, for example, the display can be a light that turns from one colour (e.g. red) to

another colour (e.g. green) when the pH of a solution in the container has reached a predetermined value.

The dispenser is typically formed from a suitable plastics materials. For example, the dispenser can comprise a dispensing chamber formed by injection moulding from plastics, and a plastics cap which serves as the handle.

The term "water dispersible substance" as used herein encompasses substances that are soluble in water as well as substances that are insoluble or sparingly soluble in water but can be dispersed in a finely divided form in water, for example as a suspension or emulsion. Thus the term dispersion includes solutions, suspensions and emulsions. In one preferred embodiment, the dispersion is a solution.

The term "aqueous medium" as used herein is used in its usual sense and covers water per se as well as water in which water soluble or water dispersible substances are dissolved or dispersed. Thus, for example, it can refer to substantially pure water such as de-ionised water, distilled water or tap water, or it can refer to solutions such as saline solutions or solutions containing dissolved substances such as disinfectants.

The water-swellable or water-soluble biopolymer has encapsulated therein a water-dispersible substance. The dosage units can take the form of capsules in which the water dispersible substance is surrounded by an outer skin of biopolymer or can take the form of a polymer matrix in which the water dispersible substance is distributed.

The capsules can be microcapsules (e.g. they can have diameter of less than 1 mm) or they can have a minimum dimension of greater than or equal to 1 mm.

When the dosage units are in the form of a matrix, they can have a minimum dimension of less than 1mm or they can have a minimum dimension of equal to or greater than 1 mm. For example, they can have a minimum dimension of at least 1 mm (for example at least 1.5 mm or at least 2 mm or at least 2.5 mm) and a maximum dimension of at least mm (for example at least 1.5 mm or at least 2 mm or at least 2.5 mm or at least 3 mm or at least 3.5 or at least 4 mm).

In one preferred embodiment, the dosage units have a maximum dimension (e.g. diameter) of at least 10 mm, or at least 15 mm, for example in the range 15-20 mm. In this embodiment, the dosage units may have a minimum dimension (e g. thickness) of 1 to 5 mm, e.g. 1.5 to 3 mm.

In one embodiment, the dosage units are in the form of discs or biscuits.

The term "biopolymer" as used herein refers to a polymer which is derived at least in part from a renewable organic non-petroleum and non-coal source material.

Thus the biopolymer may be formed entirely from monomer units ("bio-monomers") derived from a renewable organic non-petroleum and non-coal source material, or it can be formed from a mixture of bio-monomers or non-bio-monomers. The biopolymer may also consist of a mixture of one or more polymers formed entirely from bio-monomer units and one or more polymers formed from monomers derived from non-renewable (e.g. petroleum or coal) sources. Unless the context indicates otherwise, the term "biopolymer" as used herein embraces both polymers formed entirely from renewable organic sources or polymers or mixtures of polymers containing monomers derived from both renewable and non-renewable sources.

In one embodiment, at least 50% (e.g. at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95%, or at least 99%, for example 100%) of the monomer units in the biopolymer are derived from renewable organic non-petroleum and non-coal source materials.

The organic source material is preferably an organic source that can be grown or cropped on a regular basis, for example at intervals of one day or less, or one week or less, or one month or less, or three months or less, or six months or less, or on an annual, biennial or triennial basis, or at intervals of up to ten years or up to twenty years, or up to thirty years or up to forty years or up to fifty years..

More preferably, the organic source material is derived from an organic source that can be cropped on an annual or part annual basis.

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Examples of organic source materials or feedstocks are plant crops such as cereals, grasses, maize, sugar beet and sugar cane.

Examples of cereals include wheat, barley, oats and rice.

Particular examples of organic source materials include sugar, potatoes (e.g. potato skins), 5 maize, corn stover, grasses, wheat and rice straws, and bagasse.

One preferred biopolymer is polylactide (PLA) which is a biodegradable, thermoplastic, aliphatic polyester. Polylactide can be produced from a variety of renewable feedstocks, for example by the fermentation of agricultural by-products such as corn starch or other starch-rich substances like potato skins, maize, sugar or wheat to give lactic acid followed 10 by polymerization to give the PLA.

Several forms of polylactide exist. Poly-L-lactide (PLLA) results from the polymerization of L,L-lactide (also known as L-lactide). PLLA has a crystallinity of around 37%, a glass transition temperature between 50-80° C and a melting temperature between 173-178° C.

The polymerization of a racemic mixture L- and D-lactides leads to the synthesis of poly-15 DL-lactide (PDLLA) which is not crystalline but amorphous.

Polylactides are available commercially from NatureWorks LLC, a wholly owned subsidiary of Cargill Corporation, Toyota (Japan), Hycail (The Netherlands) and Galactic (Belgium).

Polylactides can be prepared by a variety of methods including the processes described in 20 WO 93/15127 (Cargill) and WO 01/38284 (Cargill Dow LLC) and references cited therein.

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The polylactide biopolymers may be homopolymers of copolymers with non-lactic acid

• monomers such as glycolic acid. Examples of copolymers include lactide glycolide

• copolymers, lactide caprolactone copolymers, lactide cyclic carbonate polymers, lactide • • • •

25 derived poly(ester amides),

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.**. ; Other examples of biopolymers include:

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■ Chitin-based biopolymers such as chitosan (see for example WO 01/68714 to Cargill, Inc.);

■ Gelling hemicelluloses such as the oxidatively gelled hemicelluloses and arabinoxylans disclosed in WO 01/49320 (Cambridge Biopolymers);

5 ■ Plastarch Material (a biodegradable thermoplastic material formed from modified cornstarch); and

■ Polyhydroxyalkanoates (e.g. Biopol) such as poly-3-hydroxybutyrate, poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO) and their copolymers

10 The biopolymer may be a water soluble biopolymer but preferably it is insoluble.

When the biopolymer is insoluble, it will typically be swellable to allow water to penetrate the matrix or capsule so as to elute the water dispersible substance.

The biopolymer may be mixed with or form part of a copolymer with a non-biopolymer material. For example, the biopolymer may be mixed with a polymer as described in any 15 of WO 00/06610, WO 00/06533, WO 00/06658, WO 01/40874 and WO 2007/012860.

When the biopolymer is mixed with or copolymerised with a non-biopolymer or monomer of a non-biopolymer, one particular polymer is formed by the polymerisation of a dienyl quaternary amine monomer either alone or in the presence of a co-monomer. For example, the dienyl quaternary amine monomer may be a monomer as described in WO 20 2007/012860 (Novel Polymer Solutions).

Where the biopolymer or biopolymer copolymer is intended to be insoluble in water, but water-sweilable, it is typically a crosslinked polymer. Crosslinking can be accomplished in any of a variety of ways well known to the skilled person. For example, Crosslinking ;•••• can be carried out under oxidative conditions, or thermal conditions, by means of an **"* .25 initiator or by means of radiation, e.g. UV radiation, or a combination thereof. The particular method of crosslinking will be selected according to the nature of the monomer being used and the mechanism by which it undergoes polymerisation.

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Where the biopolymer is mixed with a non-biopolymer or the biopolymer monomer is polymerised with a co-monomer which is not derived from a renewable organic source, particularly examples of non-biopolymers are those formed by the cyclopolymerisation of a dienyl quaternary amine monomer as described in WO 2007/012860. More particularly, the polymers are those formed by the cyclopolymerisation of quaternary diallylamine monomers The diallylamine monomers can be derived from cyclic amines such as piperidine and piperidine derivatives or from acyclic amines such as long chain hydrocarbyl amines A monomer may have a single dienyl quaternary amine group present or may have two or more dienyl quaternary amine groups present, each linked by a suitable linking chain such as a hydrocarbon chain. Where two or more such dienyl quaternary amine groups are present, they can form cross links when polymerised to form a three dimensional gel network.

When it is required that the polymer should be water soluble, the polymer will typically not be crosslinked and will usually have only a single dienyl quaternary amine group present. One example of a monomer from which a soluble polymer can be formed is N,N-diallylpiperidinium halide, e.g. N,N-diallypiperidinium bromide.

The water dispersible substance encapsulated by the biopolymer can be any of a variety of such substances but, in one embodiment, the water dispersible substance is a liquid, and in particular a liquid concentrate. In this embodiment, the dosage unit may comprise a matrix of water swellable or water soluble biopolymer within which are dispersed pockets of encapsulated water dispersible substance.

The liquid can be a corrosive substance such as an acid or alkali or bleaches as well as any of a wide range of other water dispersible substances.

Other examples of water dispersible substances that can be encapsulated include commercial, domestic and retail cleaning products and chemicals.

The biopolymer is selected such that it is compatible with the water dispersible substance that it encapsulates, i.e. it is not degraded or dissolved by the substance.

The dosage units may contain a predetermined or metered amount of the water dispersible substance. Thus, for example, the dosage units may each be of a predetermined

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substantially uniform weight. Alternatively, the dosage units may vary in weight and content.

In one preferred embodiment, the water dispersible substance is an acid such as nitric acid or sulphuric acid or a bleach.

The dosage units can be formed by simply mixing (e.g. shear mixing) the monomer and water dispersible substance, dividing the mixture into portions of a desired volume and then polymerising the monomer.

The mixture may be divided into portions by using a pipette to measure out predetermined volumes and deposit the predetermined volume of mixture onto an inert surface or into a mould followed by curing of the mixture.

By encapsulating the water dispersible substance to form a dry product, it can be transported with greater security and safety in ordinary mailing packaging and does not need to be contained within drums or bottles.

In another aspect, the invention provides a method for preparing an aqueous dispersion of a water dispersible substance, which method comprises placing a dispenser as hereinbefore defined in a container containing an aqueous medium such as distilled water or tap water and agitating or stirring the dispenser in the aqueous medium to swell or dissolve the encapsulating biopolymer and elute the water dispersible substance.

In a further aspect, the invention provides a non-pharmaceutical dosage unit comprising a matrix or shell formed from a biopolymer as defined herein and, disposed within the matrix or shell, a water dispersible substance.

The invention will now be illustrated in more detail (but not limited) by reference to the specific embodiment shown in the drawings

Brief Description of the Drawings

Figure 1 is a schematic partial side sectional view of a dispenser according to one embodiment of the invention.

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Figure 2 is a schematic partial side sectional view of the dispenser of Figure 1 in use. Detailed Description of the Invention

As shown in Figure 1, a dispenser according to one embodiment of the invention comprises a tubular body 2, the wall of which has a plurality of holes 4 extending around 5 its circumference. In the drawing, the holes are shown as having an elongated octagonal shape but they may alternatively be of circular, oval, rectangular or any other shape. The tubular body is formed by injection moulding from a suitable plastics material. The interior 8 of the tubular body 2 serves as a dispensing chamber.

Attached to the upper end of the tubular body 2 is a cap 6 which is removably attached by 10 any of a screw thread, a snap fit connection, a bayonet fitting or by frictional engagement. The cap, which is also formed by injection moulding from a suitable plastics material, is configured so that it can be held easily in a person's hand, and therefore functions as a handle.

Mounted within the dispensing chamber near to its bottom is a pH probe 10 which is 15 connected via wire 12 to a display and associated electronics in the cap 6. In this embodiment, the display takes the form of an LED indicator light 14 which lights up when the pH probe senses that a solution in which it is immersed has reached a particular value.

Contained within the dispensing chamber 8 is a plurality of discs or "biscuits" 16 which may be stacked one on top of another or stacked loosely within the container. The biscuits 20 are formed from a water swellable or water soluble biopolymer as described herein and in particular a polylactide biopolymer.

. Encapsulated within the biopolymer is a water-dispersible substance which may be, for . example, an acidic liquid substance. By way of example, the resulting biscuits or discs can be approximately 2 mm in depth and about 19 mm in diameter.

By encapsulating the acidic liquid substance in a polymer matrix, the substance is converted into a dry form that can readily be transported to a customer using a suitable mailing container.

The customer can then use the dispenser of the invention to generate a dispersion (e g. a solution) of the dispersible substance. This is done by immersing the dispensing chamber in a container C containing an aqueous medium such as tap water so that the holes 4 in the wall of the dispensing chamber are below the level of the aqueous medium, as shown in Figure 2. The dispenser, which is held in the user's hand by the handle 6, is then moved in a stirring movement or is agitated back and forth in the aqueous medium so that the acidic dispersible substance leaches out into the aqueous medium.

Where the biscuits are formed from a water soluble material, the action of the water is to dissolve the biscuits, thereby forming a solution of polymer and the dispersible substance which then passes out through the holes 4 and into the container. Alternatively, if the biopolymer is a water-insoluble but water-swellable biopolymer, the polymer will swell to allow penetration of the water, thereby allowing the dispersible substance to be eluted from the polymer and out into the container. In either case, the pH probe will indicate when the solution has reached the required pH value thereby indicating to the user that he or she can remove the dispenser from the container.

Once used, the dispenser can be rinsed and allowed to dry and then returned to the manufacturer for refilling or recycling. Alternatively, the cap may be removed and the dispensing chamber recharged by adding a required number of biscuits.

A substantial advantage of the dispenser of the invention is that it enables corrosive (and non-corrosive) substances to be transported and stored in a safe manner and then converted into a more diluted liquid form whenever required. The shape of the dispenser and the fact that it can be held in the hand means that it can be stirred or otherwise moved about in a container of water in order to speed up the rate at which the dispersible substance is eluted from the polymer.

The embodiments illustrated in the Figures represent merely one way of putting the invention into effect and it will readily be apparent that numerous modifications and alterations may be made to the specific embodiment shown without departing from the principles underlying the invention. All such modifications and alterations are intended to be embraced by this application.

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Claims

1. A dispenser for dispensing a water dispersible substance, the dispenser having a handle and a dispensing chamber, the dispensing chamber having a plurality of openings in a wall thereof and containing one or more dosage units comprising a water-swellable or water-soluble biopolymer, the biopolymer being a polymer which is derived at least in part from a renewable organic non-petroleum and non-coal source material; wherein the biopolymer has encapsulated therein a water dispersible substance; the dispenser being configured such that when the dispensing chamber is held in a container containing an aqueous medium and agitated or stirred within the container, the aqueous medium can pass through the openings in the wall of the chamber to elute the water-dispersible substance from the biopolymer thereby to provide a dispersion of the water dispersible substance in the aqueous medium.

2. A dispenser according to claim 1 which comprises an elongate body, an upper part of the elongate body serving as the handle and the dispensing chamber being disposed below the handle.

3. A dispenser according to claim 2 wherein which has a tubular body secured to the handle and the interior of the tubular body serves as the dispensing chamber.

4. A dispenser according to claim 3 wherein the tubular body has a rectangular or circular cross section.

5. A dispenser according to any one of the preceding claims wherein the openings in the wall of the dispensing chamber are of a size in the range from 1 to 10 mm in diameter (or largest dimension where non circular), more usually 2 to 5 mm in diameter (or largest dimension where non-circular).

6. A dispenser according to any one of the preceding claims wherein the handle takes the form of a cap that can be replaceably removed to allow the dispensing chamber to be refilled with dosage units.

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7. A dispenser according to any one of the preceding claims which is provided with monitoring means for monitoring one or more physico-chemical parameters of the dispersion

8. A dispenser according to claim 7 wherein the monitoring means comprises a 5 means for monitoring the pH of the dispersion.

9. A dispenser according to any one of the preceding claims wherein the dosage units have a maximum dimension (e.g. diameter) of at least 10 mm, or at least 15 mm, for example in the range 15-20 mm.

10. A dispenser according to claim 9 wherein the dosage units are in the form of discs

10 or biscuits.

11. A dispenser according to any one of the preceding claims wherein the biopolymer is insoluble in water, but water-swellable, and is a crosslinked polymer.

12. A dispenser according to any one of the preceding claims wherein the water dispersible substance encapsulated by the polymer is a liquid, and in particular a

15 liquid concentrate.

13. A dispenser according to claim 12 wherein the liquid is a corrosive substance such as an acid or alkali or bleaches.

14. A dispenser substantially as described herein with reference to the accompanying drawings.

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15. A dispenser according to any one of the preceding claims wherein the biopolymer is one in which at least 50% (e.g. at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95%, or at least 99%, for example 100%) of monomer units in the biopolymer are derived from renewable organic non-petroleum and non-coal source materials.

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16. A dispenser according to any one of the preceding claims wherein the organic

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source material is an organic source that can be grown or cropped at intervals of

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one day or less, or one week or less, or one month or less, or three months or less,

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or six months or less, or on an annual, biennial or triennial basis, or at intervals of up to ten years or up to twenty years, or up to thirty years or up to forty years or up to fifty years.

A dispenser according to claim 16 wherein the organic source material is derived from an organic source that can be cropped on an annual or part annual basis

A dispenser according to claim 1 wherein the organic source material is selected from plant crops such as cereals, grasses, maize, potatoes, sugar beet and sugar.

A dispenser according to any one of the preceding claims wherein the biopolymer is polylactide (PLA) or a copolymer thereof.

A dispenser according to claim 19 wherein the biopolymer is polylactide homopolymer.

A method for preparing an aqueous dispersion of a water dispersible substance, which method comprises placing a dispenser as defined in any one of the preceding claims in a container of water and agitating or stirring the dispenser in the to swell or dissolve the encapsulating biopolymer and elute the water dispersible substance.