WO2013087385A1

WO2013087385A1 - Container - packed product comprising a non stick coating on the inner wall

Info

Publication number: WO2013087385A1
Application number: PCT/EP2012/073262
Authority: WO
Inventors: Wenting Chen; Qingsheng Tao; Xiaoliang Wang
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Unilever Limited; Conopco, Inc., D/B/A Unilever
Priority date: 2011-12-13
Filing date: 2012-11-21
Publication date: 2013-06-20

Abstract

Disclosed is a container-packed product comprising : a cavity delimited by a wall and containing product, wherein the wall has an inner surface; and aqueous coating applied to at least a portion of the inner surface of the wall, wherein the coating has a viscosity of at least 20 mPa∙s at a temperature of 25 °C and shear rate of 1 s ^-1, and wherein the coating comprises wetting agent.

Description

CONTAINER - PACKED PRODUCT COMPRISING A NON STICK COATING ON THE INNER WALL

FIELD OF THE INVENTION

The present invention relates to a container-packed product. More particularly the present invention relates to container-packed products which comprise a coating on an inner surface of a wall of the container to aid evacuation of the product from the container.

BACKGROUND OF THE INVENTION

Many consumer goods, such as food products, personal care products or household care products, are packed in containers which serve as both a dispenser and store for the product. For products which have low resistance to flow and which are not sticky, complete evacuation from the container can often be achieved, even under the action of gravity alone.

However, some products that are sticky and/or viscous do not freely flow under the influence of gravity and so specially-adapted containers have been developed for dispensing such products. Squeeze containers have been found to work best for helping evacuate product by application of manual force by the consumer. Bottom-opening containers (also known as "tottles") have also been found advantageous for helping with evacuation by employing the force of gravity to help push the product out through a spout member connected to the lower end of the container over the bottom opening, or a spout opening, through which the viscous product is discharged.

Another approach is to apply coatings to the inside of the container.

US patent 6,247,603 (CONTINENTAL PLASTIC CONTAINERS) discloses a dispensing apparatus for increasing product removal. The apparatus comprises a container comprising an outlet and a wall having an inner surface, the wall inner surface defining a chamber, a liquid coating on the inner surface; and a product in the container. The coating substantially covers the wall inner surface, is immiscible in the product, is liquid at room temperature, and is substantially non- absorbent to the wall. Exemplified coatings are natural oil or mineral oil.

Unfortunately the present inventors have found that oily materials can be detrimental to the quality of some products and therefore have several

disadvantages. For example an oily coating may interfere with the stability of foam-containing or emulsion-based products, may alter the surface appearance of products on dispensing (i.e. by giving an oily surface) and/or may taint the taste of food products (especially if the oils oxidise and turn rancid). Therefore the present inventors have recognized a need for container-packed products which allow for almost complete evacuation of the product but without one or more of the aforementioned disadvantages.

DEFINITIONS

Aqueous

As used herein "aqueous" refers to a composition (e.g. a coating) comprising water in an amount of at least 30% by weight.

Viscosity

Viscosity values referred to herein are those measured at a temperature of 25 °C and shear rate of 1 s Viscosity can be determined, for example, using a logarithmic shear rate sweep of from 0.01 -1000 s^"1 with 31 points and each point lasting for 10 seconds. Suitably an instrument such as a Physica™ MCR 301 rheometer from Anton Paar can be used employing a cone-and-plate geometry (50 mm diameter, 1 ° cone). Miscellaneous

Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use may optionally be understood as modified by the word "about".

All amounts are by weight of the final coating, unless otherwise specified.

The term "liquid" as used herein means that the material is fluid at 4 degrees C.

It should be noted that in specifying any range of values, any particular upper value can be associated with any particular lower value.

For the avoidance of doubt, the word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of". In other words, the listed steps or options need not be exhaustive.

The disclosure of the invention as found herein is to be considered to cover all embodiments as found in the claims as being multiply dependent upon each other irrespective of the fact that claims may be found without multiple dependency or redundancy.

Where a feature is disclosed with respect to a particular aspect of the invention (for example a product of the invention), such disclosure is also to be considered to apply to any other aspect of the invention (for example a method of the invention) mutatis mutandis. SUMMARY OF THE INVENTION

In a first aspect, the present invention is directed to a container-packed product comprising:

- a cavity delimited by a wall and containing product, wherein the wall has an inner surface; and

aqueous coating applied to at least a portion of the inner surface of the wall, wherein the coating has a viscosity of at least 20 mPa*s at a temperature of 25 °C and shear rate of 1 s and wherein the coating comprises wetting agent.

In a second aspect, the invention is directed to a method for manufacturing a container-packed product, the method comprising the steps of:

a) providing a container comprising a cavity delimited by a wall,

wherein the wall has an inner surface,

b) applying an aqueous coating to at least a portion of the inner surface of the wall; and

c) dosing the product into the cavity;

wherein the coating has a viscosity of at least 20 mPa*s at a temperature of 25 °C and shear rate of 1 s^"1 ; and comprises wetting agent.

The method of the second aspect is particularly suitable for manufacturing the container-packed product of the first aspect. All other aspects of the present invention will more readily become apparent upon considering the detailed description and examples which follow. DETAILED DESCRIPTION

The present inventors have unexpectedly found that aqueous coatings having specific properties can be applied to the inside of containers to assist in

evacuation of products from the containers.

The only limitation to the container for use in the present invention is that it comprises a cavity delimited by a wall wherein the wall has an inner surface.

Preferably, however, the container comprises an aperture through which a product can be dispensed from the cavity. Especially preferred are squeeze containers and so in a preferred embodiment the wall is deformable by manual force to aid dispensing of the product.

The form of the container may be, for example, a bottle, tottle, jar, pouch, tube, sachet, can or the like. Preferably however the container is a bottle or tottle, especially a bottle or tottle which comprises a neck which narrows towards the dispensing aperture.

The container is preferably formed from plastic as plastics are typically easy to mould and deform but often (in uncoated form) present surfaces which readily stick to products and so prevent complete evacuation thereof. Especially preferred are containers wherein at least the inner surface of the wall comprises plastic, more preferably the wall consists of plastic. Especially preferred plastics are those comprising polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) or a combination thereof. The container (or at least the wall thereof) may be moulded from plastic, for example it may be blow moulded or injection-moulded.

The cavity contains product. The present invention allows for almost complete evacuation of product even where the cavity is initially substantially filled with product. In particular it is preferred that the product occupies at least 80% of the total volume of the cavity, more preferably at least 90% and most preferably from 95-100%. Typically the product will be a paste, gel or viscous liquid, most preferably a viscous liquid. The present invention is especially advantageous wherein the product has a viscosity of at least 20 mPa-s, more preferably at least 100 mPa-s, and most preferably from 1 ,000 to 1 ,000,000 mPa-s. The product is preferably selected from a food product, a personal care product or a household care product. The food product may, for example, be a sauce or dressing product (such as mayonnaise, low fat mayonnaise or the like). The personal care product may, for example, be a hair care product (such as a shampoo and/or hair conditioner).

Although the coatings for use in the present invention are aqueous, they have unexpectedly been found to aid evacuation of products even where the products themselves comprise substantial amounts of water. For example the product may comprise at least 20% water, more preferably at least 25% water by weight of the product. In a preferred embodiment the product is aqueous, more preferably the product comprises at least 50% water, more preferably still at least 70% or most preferably from 80 to 95% water by weight of the product. In one embodiment the product comprises or is an oil-in-water emulsion. The coating is aqueous and preferably comprises water in an amount of at least 50% by weight of the coating, more preferably at least 70%, more preferably still at least 80%, even more preferably at least 90% and most preferably from 95 to 99.9%. Where the coating comprises multiple phases it is preferred that at least the continuous phase is aqueous. As the coating is aqueous it typically has not been substantially dried or cured after application to the inner surface of the cavity (at least to the extent that the coating retains at least 30% water by weight of the coating, preferably at least 50%, more preferably at least 70%, more preferably still at least 80%, even more preferably at least 90% and most preferably from 95 to 99.9%). One advantage of the relatively high viscosity and presence of a wetting agent in the coatings of the present invention is that they effectively coat the wall and stay in place even without the use of a drying/curing step. To ensure that the coating is capable of remaining on the container wall during manufacture and/or storage of the container packed product, the coating has a viscosity of at least 20 mPa*s. Preferably the coating has a viscosity of at least 30 mPa-s, more preferably at least 100 mPa*s and most preferably at least 300 mPa-s. If the viscosity of the coating is too high, however it may become difficult to apply evenly onto the wall. Therefore it is preferred that the coating has a viscosity of less than 1 ,000,000 mPa*s, more preferably the coating has a viscosity of less than 100,000 mPa*s and most preferably coating has a viscosity of less than 50,000 mPa^«s. Any known method for providing viscosity to aqueous compositions may be used to achieve the viscosity of the coating. Conveniently, however, the coating comprises polymer, preferably biopolymer. Examples of suitable biopolymers include, but are not limited to, proteins, polysaccharides, polyphenols, polyhydroxy alkanoates or mixtures thereof. Especially preferred are polysaccharides. Thus the polymer may, for example, comprise one or more polysaccharides selected from chitosan, polyglactomannan (such as guar gum and/or locust bean gum), polyglucomannan (such as konjac mannan), starch (including modified and/or hydrolysed starch), xanthan gum, alginate, dextran, welan gum, gellan gum, agarose, pullulan, gum arabic, pectin, cellulose (including carboxymethylcellulose and/or microcrystalline cellulose), carrageenans (such as iota, lamda and/or kappa carrageenan), derivatives thereof, mixtures thereof and the like. The biopolymer may have any suitable morphology such as, for example, globule, rod or fibre. Preferably however the biopolymer is in the form of rods and/or fibres. To aid the ability of the coating to remain on the container wall during storage, it is preferred that at least part of the polymer is insoluble in water (at 4 °C) and is thus present in the coating as a dispersion. Especially preferred in this respect is that the polymer comprises insoluble fibre. More preferably the polymer comprises or is microcrystalline cellulose.

The amount of polymer is limited only insofar as it is sufficient to provide the required viscosity to the coating. For example, the coating may comprise the polymer in an amount of from 0.01 to 10% by weight of the coating, more preferably from 0.1 to 7%, more preferably still from 0.3 to 5% and most preferably from 0.5 to 3%.

The coating comprises wetting agent to aid spreading of the coating on the container wall. Suitably the wetting agent is a surfactant selected from cationic surfactant, anionic surfactant, nonionic surfactant, amphoteric surfactant or mixture thereof. Suitable anionic surfactants include the sodium, magnesium, ammonium or ethanolamine salts of C₈ to d₈ alkyl sulphates (for example sodium lauryl sulphate), C₈ to C-|₈ alkyl sulphosuccinates (for example dioctyl sodium sulphosuccinate), C₈ to C-|₈ alkyl sulphoacetates (such as sodium lauryl sulphoacetate), C₈ to Ci₈ alkyl sarcosinates (such as sodium lauryl sarcosinate), C₈ to C-is alkyl phosphates (which can optionally comprise up to 10 ethylene oxide and/or propylene oxide units) and sulphated monoglycerides. Suitable amphoteric surfactants include betaines or sulphobetaines. More preferably the surfactant comprises or is nonionic surfactant. Suitable non-ionic surfactants include optionally polyethoxylated fatty acid sorbitan esters, ethoxylated fatty acids, esters of polyethylene glycol, ethoxylates of fatty acid monoglycerides and diglycerides, and ethylene oxide/propylene oxide block polymers. Also suitable are copolymers such as polyethylene-polyethylene oxide (PE-PEO), polypropylene-polyethylene oxide (PP-PEO), polybutadiene-polyethylene oxide (PBD-PEO), polyethylene terephthalate-polyoxyethylene terephthalate (PET-POET) or a mixture thereof. Most preferably the wetting agent comprises polysorbate (e.g., Tween^® 20 or Tween^® 80), polyoxyethylene alkylphenol ether (e.g., Triton X-100 or OP-10), PET-POET copolymer (e.g., TexCare™ SRN 300) or a mixture thereof.

Where the container wall comprises PET, it is especially preferred that the wetting agent comprises or is polysorbate.

Where the container wall comprises PE, it is especially preferred that the wetting agent comprises or is polyoxyethylene alkylphenol ether. The amount of wetting agent is limited only insofar as it is sufficient to aid spreading of the coating on the wall. Preferably the coating comprises the wetting agent in an amount of from 0.01 to 10% by weight of the coating, more preferably from 0.05 to 5%, more preferably still from 0.1 to 3%, and most preferably from 0.2 to 2% .

The coating is aqueous and so under certain conditions may be susceptible to spoilage. Thus it is preferable that the coating is acidic and/or comprises preservative. For example the coating may have a pH (at 25 °C) of less than 7, more preferably less than 6, more preferably still less than 5 and most preferably a pH of from 1 to 4. Additionally or alternatively the coating may comprise an effective amount (for example from 0.0001 to 5% preservative by weight of the coating, more preferably from 0.01 % to 2% by weight) of preservative. Suitable preservatives include, for example, benzoic acid (and/or salt thereof), sorbic acid (and/or salt thereof), natamycin, alkyl esters of para-hydroxybenzoic acid, hydantoin derivatives, propionate salts, phenoxyethanol, methyl paraben, propyl paraben, butyl paraben, isobutyl paraben, imidazolidinyl urea, sodium

dehydroacetate, benzyl alcohol or a mixture thereof.

The aqueous coating is applied to at least a portion of the inner surface of the wall and forms a layer between the product and the portion of the wall. Without wishing to be bound by theory the present inventors believe that the coating of the present invention allows more complete evacuation of the product from the container owing to creation of a slip layer at the inner surface of the wall to which it is applied.

Preferably the portion of the inner surface of the wall to which the coating is applied covers at least 50% of the total inner surface area of the wall delimiting the cavity, more preferably at least 80%, more preferably still at least 90% and most preferably from 95 to 100%.

The coating is preferably not applied in too thick a layer as otherwise the volume allowed for accommodation of the product will be reduced. Therefore preferably the coating has a thickness of less than 3 mm, more preferably less than 2 mm, more preferably still less than 1 mm and most preferably the coating has a thickness in the range of from 0.1 micron to 0.5 mm.

The composition of the coating is different to the composition of the product. For example, if both the coating and the product comprise the polymer then typically the concentration of polymer in the coating (weight % of total coating) will be at least 1 .5 times the concentration of polymer in the product (weight % of total product), more preferably at least 2 times, and most preferably from 5 to 1000 times. Additionally or alternatively, the viscosity of the coating may be less than that of the product. For example the product viscosity may be at least 2 times, more preferably from 10 to 1000 times more than the coating viscosity. The container-packed product typically has excellent emptying performance. In particular it is preferred that at least 90% by weight of the product is capable of being evacuated from the cavity by force of gravity and/or manual force and without permanently deforming the container. More preferably at least 95%, most preferably from 97 to 100% by weight of the product is capable of being

evacuated from the cavity by gravity and/or manual force and without permanently deforming the container.

The container-packed product may be manufactured in any convenient way but in a preferred embodiment, the packed product is manufactured by a method comprising the steps of:

a) providing the container comprising a cavity delimited by a wall,

wherein the wall has an inner surface,

b) applying the aqueous coating to at least a portion of the inner

surface of the wall; and

c) dosing the product into the cavity.

The coating may be applied in step (b) in any convenient way. For example the coating may be applied by spraying liquid coating onto the wall. Additionally or alternatively, liquid coating may be dosed into the cavity and the container agitated or otherwise manipulated to spread the coating around the inner surface of the wall. In some instances it may be advantageous to introduce excess coating into the cavity during step (b) with said excess being drained (or otherwise removed) from the cavity prior to step (c).

Advantageously the time between the step (b) of applying the coating and the step (c) of dosing the product into the cavity is kept to a minimum to avoid drying, damage and/or spoilage of the coating. Preferably the time between steps (b) and (c) is less than 1 day, more preferably less than 12 hours, more preferably still less than 8 hours, even more preferably less than 5 hours and most preferably from 10 seconds to 2 hours.

To ensure that the coating remains aqueous after application, the coating is typically not subjected to a drying or curing step during and/or after step (b).

The container and/or product are preferably sanitized (e.g. by heat and/or chemical antimicrobial agent) separately (i.e. before step (c)) to avoid any deterioration of the coating which may be effected by post-dosing heat treatment. In certain embodiments it may be advantageous to perform steps (b) and (c) in a sterile environment.

EXAMPLES

The following examples are provided to facilitate an understanding of the invention. The examples are not intended to limit the scope of the claims.

Example 1

This example demonstrates manufacture of container-packed dressing according to the present invention.

A coating composition was prepared as follows. 0.75 parts by weight of

polysorbate 20 (Tween 20 supplied by Shanghai Richem International Co, Ltd) and 1 part by weight of a mixture of Microcrystalline Cellulose and

Carboxymethylcellulose Sodium (VIVAPUR^® MCG 81 1 P supplied by JRS

PHARMA GmbH & Co) were dispersed in 80 parts by weight deionised water with vigorous agitation at 25 °C for 30 minutes. A small quantity of table vinegar was then added to adjust pH to 3.6. The mixture was then made to 100 parts by weight with a sufficient quantity of deionised water. The final mixture was homogenized with a high pressure homogenizer (Niro Soavi homogenizer operating at 800 bar). 2.5 ml of the coating composition were accurately pipetted into a PET tottle having a brim full capacity of 488 ml. The lid was then placed on the tottle and the closed tottle shaken and turned to evenly coat the tottle's inner surface. The coated tottle was then held upright (i.e. with the lid at the bottom) with the lid open for 20 minutes to allow excess coating to drain from the tottle (about 1 .3 g of coating remained in the tottle following draining). The tottle was then stood upside down (i.e. with the lid at the top) for 10 minutes. Four hundred and eighty eight grams of Hellmann's^® light mayonnaise were then filled into the coated tottle and the lid sealed.

Emptying performance was judged as follows. A quarter of the mayonnaise was squeezed from the tottle. The tottle was then stored upright for 20 minutes at 25 °C. A further quantity of mayonnaise was squeezed from the tottle until the tottle was about half empty. The tottle was then stored upright for 5 days in a refrigerator (4 °C) before being squeezed to dispense a further quarter of the original contents. The tottle was then stored upright for 20 minutes at 25 °C and squeezed again until almost empty. The tottle was then stored upright for a further 5 days in the refrigerator before being squeezed to dispense as much of the remaining contents as possible.

After emptying a total of 9.8 g of mayonnaise remained in the tottle and there was very little visible residue on the sides of the tottle. In contrast an identical test with an uncoated tottle resulted in 62 g of mayonnaise remaining and visible residue on the tottle wall.

Example 2

An experiment similar to Example 1 was performed except that the 0.75 parts by weight of polysorbate 20 were replaced by 1 .5 parts by weight of PET-POET graft copolymer (TexCare '^M SRN 300 from Clarianr) and the 1 part by weight of a mixture of Microcrystalline Cellulose and Carboxymethylcellulose Sodium was replaced by 5 parts by weight of chitosan (supplied by Eastar Group Co Ltd, Shanghai). Again the coated container showed superior emptying performance compared with an identical uncoated container.

Example 3

An experiment similar to Example 1 was performed except that the 0.75 parts by weight of polysorbate 20 were replaced by 1 .5 parts by weight of PET-POET graft copolymer (TexCare™ SRN 300 from Clariant^®) and the 1 part by weight of a mixture of Microcrystalline Cellulose and Carboxymethylcellulose Sodium was replaced by 0.5 parts by weight of guar gum (supplied by Foodchem International Corporation). Again the coated container showed superior emptying performance compared with an identical uncoated container.

Example 4

An experiment similar to Example 1 was performed except that the 1 part by weight of a mixture of Microcrystalline Cellulose and Carboxymethylcellulose Sodium was replaced by 0.5 parts by weight of guar gum (supplied by Foodchem International Corporation). Again the coated container showed superior emptying performance compared with an identical uncoated container.

Example 5

An experiment similar to Example 1 was performed except that the amount of the mixture of Microcrystalline Cellulose and Carboxymethylcellulose Sodium was increased to 2 parts by weight. Again the coated container showed superior emptying performance compared with an identical uncoated container. Example 6

An experiment similar to Example 1 was performed except that the 0.75 parts by weight of polysorbate 20 were replaced by 2 parts by weight of polysorbate 80 (Tween 80 supplied by Shanghai Richem International Co, Ltd) and the amount of the mixture of Microcrystalline Cellulose and Carboxymethylcellulose Sodium was increased to 2 parts by weight. Again the coated container showed superior emptying performance compared with an identical uncoated container.

Example 7

An experiment similar to Example 5 was performed except that Lux^® hair conditioner was used in place of mayonnaise. Again the coated container showed superior emptying performance compared with an identical uncoated container.

Example 8

An experiment similar to Example 1 was performed except that the 0.75 parts by weight of polysorbate 20 were replaced by 2 parts by weight of polyoxyethylene octylphenol ether (OP-10 supplied by Jiangsu Haian Petrochemical Plant), the container was made of high density PE and Lux^® hair conditioner was used in place of mayonnaise. Again the coated container showed superior emptying performance compared with an identical uncoated container.

Example 9

The viscosities of coatings suitable for use in the present invention were measured. The coatings were prepared as described in Example 1 but differed in the amounts of surfactant and polymer used. Viscosity was measured immediately prior to application to the wall surface.

Table 1 shows the composition and viscosity of each coating. TABLE 1

^**At a shear rate of 1 s . Samples B and A were identical to the coatings used in Examples 1 and 5 respectively and showed excellent performance. Sample C had a relatively low viscosity and was just within the workable limit for allowing the coating to remain on the container surface during filling and storage.

Claims

A container-packed product comprising:

- aqueous coating applied to at least a portion of the inner surface of the wall, wherein the coating has a viscosity of at least 20 mPa-s at a temperature of 25 °C and shear rate of 1 s and wherein the coating comprises wetting agent.

The container-packed product as claimed in claim 1 wherein the coating has a thickness in the range of from 0.1 micron to 1 mm.

The container-packed product as claimed in any one of the previous claims wherein the coating comprises water in an amount of at least 70% by weight of the coating, preferably at least 90%.

The container-packed product as claimed in any one of the previous claims wherein the coating comprises the wetting agent in an amount of from 0.01 to 10% by weight of the coating, preferably from 0.1 to 5%.

The container-packed product as claimed in any one of the previous claims wherein the coating comprises polymer, preferably biopolymer.

The container-packed product as claimed in claim 5 wherein the coating comprises the polymer in an amount of from 0.01 to 10% by weight of the coating, preferably from 0.1 to 5%.

The container-packed product as claimed in claim 5 or claim 6 wherein at least part of the polymer is insoluble and is present in the coating as a dispersion.

8. The container-packed product as claimed in claim 7 wherein the polymer comprises insoluble fibre, preferably the polymer comprises microcrystalline cellulose.

9. The container-packed product as claimed in any one of the preceding claims wherein the container comprises an aperture through which the product can be dispensed.

10. The container-packed product as claimed in claim 9 wherein the wall is

deformable by manual force to aid dispensing of the product.

1 1 . The container-packed product as claimed in any one of the preceding claims wherein the product is selected from a food product, a personal care product or a household care product.

12. The container-packed product as claimed in claim 1 1 wherein the product is a dressing product or a hair care product.

13. The container-packed product as claimed in any one of the preceding claims wherein the inner surface of the wall comprises plastic, preferably plastic selected from PE, PP, PET or a combination thereof.

14. The container-packed product as claimed in any one of the preceding claims wherein the wetting agent comprises polysorbate, polyoxyethylene alkylphenol ether, PET-POET copolymer or a mixture thereof.

15. A method for manufacturing a container-packed product, the method

comprising the steps of:

a) providing a container comprising a cavity delimited by a wall, wherein the wall has an inner surface, b) applying an aqueous coating to at least a portion of the inner surface of the wall ; and c) dosing the product into the cavity;

wherein the coating has a viscosity of at least 20 mPa-s at a temperature of

25 °C and shear rate of 1 s^"1 ; and comprises wetting agent.