GB2299965A

GB2299965A - Sparkling bottles and method for manufacturing

Info

Publication number: GB2299965A
Application number: GB9505880A
Authority: GB
Inventors: Thomas Austin Mcroberts; Godfrey John Pitt
Original assignee: WELLS SOFT DRINKS Ltd
Current assignee: WELLS SOFT DRINKS Ltd
Priority date: 1995-03-23
Filing date: 1995-03-23
Publication date: 1996-10-23
Also published as: GB9505880D0

Abstract

A plastics container and a method for forming a plastics container, wherein the material from which the container is formed comprises a quantity of particulate matter, the particulate matter being visually distinct from the remainder of the material. The materials comprises a resin. The particulate matter is preferably reflective, and may conveniently comprise metallic flakes, such that a "sparkling" appearance is imparted to the container. Such an appearance may be used to indicate the presence of a carbonated beverage within the container, or merely to provide an aesthetically pleasing appearance to the container. The container is formed by blow-moulding after forming a preform from the material by extrusion or injection moulding.

Description

Title: Sparkling Bottles Description of Invention This invention relates to a method for forming plastics containers, and primarily but not exclusively to a method for forming plastic containers for storage of beverages.

Plastics containers such as bottles, may be produced using the known technique of blow moulding, in which a heated parison of plastics material is placed inside a substantially sealed mould, into which parison is introduced a gas, for example air, under relative high pressure such that the parison expands to fill the mould. The resulting moulded container is substantially hollow, where the shape of the outside of the walls of the container corresponds to the inside of the mould employed. The technique is relatively inexpensive, and permits of rapid operation.

Various resins are suitable for blow moulding, however it has been found that PET (polyethylene terephthalate) is most suitable for containers for carbonated beverages, since it has desirable physical properties, including a low gas porosity such that the carbonating gas (for example carbon dioxide or nitrogen) does not escape through the container, resulting in a "flat" beverage.

It will be appreciated that the use of the terms "carbonating" or "carbonated" should not be interpreted as relating specifically to carbon dioxide, and that as described above, any other suitable inert gas may be employed to render the beverage "sparkling".

The parison is generally produced by extrusion of a processing mixture of raw materials, or by injection moulding of the same.

Generally the raw materials comprise a base resin for example PET and, if necessary, a stabilizer to reduce the resulting plastics susceptibility to degradation, for example from heat or light, and a plasticiser to alter deforming properties of the resulting plastics material. Colourisers may also be added to the starting mixture so that a pigment may be imparted to the resulting product.

Often, during manufacture, a starting mixture is made up comprising the raw materials but not including the base resin, which is added to the base resin in precise quantities to create a processing mixture.

In the manufacture of plastics containers, for example bottles, the parison is often a preform, that is, a part finished formation, where part of the preform is not subsequently blow moulded.

Such a part may be, for example, a neck of the bottle, incorporating a screw thread which would preferably be formed by for example extrusion or injection moulding, and would not be suitable for forming by blow moulding.

Containers for beverages may be manufactured and marketed in a variety of differing forms, to the extent that the shape, size and colour of the containers may vary according to the type of product to be contained within them.

Products are generally distinguished from each other by a prospective consumer by virtue of labelling, the shape or texture of the container, and/or the colouring of the container.

Such distinguishing means have previously proved adequate for the purposes of identification of particular containers and hence the products contained therein, but in the case where, for example, labelling becomes detached from a number of otherwise identical or nearly identical containers, such as for example two bottles of mineral water, one sparkling and one still, it may be that they are no longer distinguishable.

It is accordingly an object of the present invention to provide an improved method for forming plastic containers.

According to one aspect of the invention, there is provided a method for forming plastics containers, comprising the steps of forming a starting mixture of generally known type, said starting mixture further comprising a quantity of particulate matter, adding a dosage of said starting mixture to an amount of base resin to produce a processing mixture, and processing said processing mixture in a known manner to produce said plastics container, wherein said particulate matter is visually distinct from the remainder of said processing mixture when said remainder has been fully processed.

Preferably said starting mixture comprises a precise, predetermined quantity of particulate matter.

Preferably, a precise dosage of starting mixture is added to a known amount of base resin to produce the processing mixture.

Preferably said particulate matter comprises reflective flakes.

Conveniently, said particulate matter comprises metallic flakes or flakes of metallic appearance.

Preferably said processing of the processing mixture comprises the formation of a preform from the processing mixture, and blow moulding at least part of said preform.

Conveniently said preform is formed by extrusion and or injection moulding of said processing mixture.

Preferably said base resin comprises PET (polyethylene terephthalate).

Preferably, said particulate matter is substantially evenly dispersed throughout said processing mixture, prior to formation of said preform.

Conveniently, said substantially even dispersion is achieved by virtue of a shearing action of a screw employed during extrusion of said preform and also by virtue of heat applied to said processing mixture during extrusion.

In the case where the preform is formed by injection moulding, said substantially even dispersion may be achieved by virtue of heat applied to said processing mixture and by virtue of a shearing action of a screw employed during injection moulding of said mixture.

Preferably, said precise dosage of said starting mixture is achieved by dosing a fixed amount at regular time intervals. Alternatively, it may be achieved by continuously dosing for the duration of the extruder screw movement.

According to a second aspect of the invention, there is provided a container of a plastics material, comprising a matrix material of known type, and further comprising particles of a further material dispersed throughout said matrix material presenting a different visual appearance to the matrix material in which it is dispersed.

Preferably the container is a bottle.

Preferably the matrix material in which the particles are dispersed is transparent.

The matrix material may alternatively be clear or coloured.

Preferably, the particles are reflective.

Conveniently the particles comprise reflective flakes.

By virtue of this reflectivity, the particles impart to the container a sparkling appearance.

Such an appearance may be used to indicate the presence in the container of an effervescent beverage.

Preferably the matrix material in which the particles are dispersed comprises PET.

Conveniently, the material may further comprise additional components such that properties of the material may be altered if desired.

The invention will now be described in greater detail.

A starting mixture is prepared, which comprises a colouriser component and other additional components such as stabilisers, for example, where a starting mixture of this type is known in the plastics containers industry.

To the starting mixture is added a precise, predetermined, quantity of particulate matter, henceforce referred to as "flitter". The flitter will generally be of a reflective nature, such that in a final product, it will present a different visual appearance to the remainder of the material.

The starting mixture, comprising the flitter, is subsequently added to the resin, for example PET (polyethylene terephthalate) at a throat of an injection moulding machine extruder, which machine is again well known in the plastics field.

The starting mixture is precisely dosed into the resin feed to form a processing mixture. This may be achieved either by adding a precise quantity at fixed and regular time intervals, or a continuous dose may be introduced during the extruder screw movement.

The extruder screw disperses and mixes the starting mixture and hence the flitter, throughout the resin by virtue of a shearing action applied by the screw, and also by virtue of heat which is applied to the processing mixture during the extrusion or injection moulding process.

Furthermore, the screw is designed such that the processing mixture is substantially homogenised prior to injection into the mould. It will be appreciated that in the case where the flitter is a metallic material, complete homogeneity may not be achieved, since the plastics part of the processing mixture may be in a liquid state, whereas the flitter will be maintained in a solid state.

The processing mixture, now in a substantially liquid state, is then injected into the injection mould apparatus so that a preform may be moulded.

The cooled mould freezes the processing mixture into a desired shape, and the flitter is thus "locked" into the PET or other suitable resin.

The preform is then removed from the mould and introduced into a blow mould. This may be a split mould which would facilitate subsequent removal of a blow moulded container.

The interior of the blow mould defines the shape of the container to be formed, and is of generally known configuration. Such a configuration may be such that the base of the container is of a petaloid configuration, which is well known to provide good resistance to internal pressures arising from gas contained within a beverage stored within the container.

The preform is heated at a temperature at which it will readily undergo blow moulding, and is then expanded until its outer surface engages and conforms with the interior surface of the mould. Expansion is effected by creating a relative high pressure within the interior of the preform.

This may be achieved either by blowing a gas, for example air, into the preform, through a blow needle or similar device. Alternatively it may be achieved by creating a vacuum about its exterior.

The mould is cooled, such that on contact of the preform with the mould, the resulting container's shape is frozen. The mould is then removed, and the container extracted.

The flitter is evenly dispersed throughout the material of the container such that a "sparkling" effect is produced. This effect serves to distinguish between containers and may indicate the presence within of a carbonated beverage.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A method for forming plastics containers, comprising the steps of forming a starting mixture of generally known type, said starting mixture further comprising a quantity of particulate matter, adding a dosage of said starting mixture to an amount of base resin to produce a processing mixture, and processing said mixture in a known manner to produce said plastics container, wherein said particulate matter is visually distinct from the remainder of said processing mixture when said remainder has been fully processed.

2. A method according to Claim 1 wherein said starting mixture comprises a precise, predetermined quantity of particulate matter.

3. A method according to Claim 1 or Claim 2 wherein a precise dosage of starting mixture is added to a known amount of base resin to produce the processing mixture.

4. A method according to any one of the preceding claims wherein said particulate matter comprises reflective flakes.

5. A method according to any one of the preceding claims wherein said particulate matter comprises metallic flakes or flakes of metallic appearance.

6. A method according to any one of the preceding claims wherein said processing of the processing mixture comprises the formation of a preform from the processing mixture, and blow moulding at least part of said preform.

7. A method according to Claim 6 wherein said preform is formed by extrusion and/or injection moulding of said processing mixture.

8. A method according to any one of the preceding claims wherein said base resin comprises PET (polyethylene terephthalate).

9. A method according to Claim 6, Claim 7 or Claim 8 wherein said particulate matter is substantially evenly dispersed throughout said processing mixture, prior to formation of said preform.

10. A method according to Claim 9, when dependent on Claim 7, wherein said substantially even dispersion is achieved by virtue of a shearing action of a screw employed during extrusion of said preform and also by virtue of heat applied to said processing mixture during extrusion.

11. A method according to Claim 9, when dependent on Claim 7, wherein when the preform is formed by injection moulding, said substantially even dispersion is achieved by virtue of heat applied to said processing mixture and by virtue of a shearing action of a screw employed during injection moulding of said mixture.

12. A method according to any one of Claims 2 to 11 wherein said precise dosage of said starting mixture is achieved by dosing a fixed amount at regular time intervals.

13. A method according to any one of Claims 7 to 11, wherein said precise dosage of said starting mixture is achieved by continuously dosing for the duration of the extruder screw movement.

14. A container of a plastics material, comprising a matrix material of known type, and further comprising particles of a further material dispersed throughout said matrix material presenting a different visual appearance to the matrix material in which it is dispersed.

15. A container according to Claim 14 wherein the container is a bottle.

16. A container according to Claim 14 or Claim 15 wherein the matrix material in which the particles are dispersed is transparent.

17. A container according to Claim 14 or Claim 15 wherein the matrix material is coloured.

18. A container according to any one of Claims 14 to 17 wherein the particles are reflective.

19. A container according to any one of Claims 14 to 18 wherein the particles comprise reflective flakes.

20. A container according to any one of Claims 14 to 19 wherein the particles impart to the container a sparkling appearance.

21. A container according to Claim 20 wherein such an appearance is used to indicate the presence in the container of an effervescent beverage.

22. A container according to any one of Claims 14 to 21 wherein the matrix material in which the particles are dispersed comprises PET (polyethylene terephthalate).

23. A container according to any one of Claims 14 to 22 wherein the base of the container is of a petaloid configuration.

24. A plastics container formed substantially in accordance with any one of claims 1 to 13.

25. A method for forming plastics containers substantially as hereinbefore described.

25. A container of a plastics material substantially as hereinbefore described.

26. Any novel feature or novel combination of features described herein.