AU655297B2 - Reinforced thermoplastic bottle - Google Patents

Description

AUSTRALIA

Patents Act 655 2 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: ft. r *4 i ft *f it 4 i

C

4 4 Cf-iC 44(4( Priority: Related Art: APPLICANT'S REF.: ACI OPERATIONS PTY. LTD.

Case 587 Name(s) of Applicant(s): Address(es) of Applicant(s): 15th Floor, 390 St. Kilda Road, Melbourne, Victoria Australia 3004, Actual Inventor(s): Address for Service is: PHILLIPS, ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367. Collins Street Melbourne, Australia, 3000 Complete Specification for the invention entitled: REINFORCED TIIERMOPLASTIC BOTTLE The following statement is a full description of this invention, including the best method of performing it known to applicant(s): P 19/11/77 2-- REINFORCED THERMOPLASTIC BOTTLE This invention relates to a thermoplastic bottle for containing liquids.

Thermoplastic containers have been used broadly for many years for a number of different applications. Whilst the present invention is not so limited, it has particular application to thermoplastic bottles which are blow moulded from a preform or parison and suitable for use in the packaging of carbonated beverages and the like.

In such bottles, the side walls are biaxially orientated and usually have a distribution of material such that the side walls are relatively thin. Due to the molecular orientation in the side walls of such :o 15 containers, the side walls can be made relatively thin (in the order of 0.3 mm) and still withstand normal carbonation pressures without unsatisfactory bulging or creep. However, internal carbonation pressures are not the only loads that a thermoplastic container of this type is likely to encounter during its commercial life. For instance, the bottles may be subjected to external transverse loads (either whilst empty or full) for example, by falling onto the ground or by something falling onto the bottle. When external loads such as i 25 these are experienced, it is not uncommon for crushing of the bottle to occur especially in the weakest thin walled portion of the bottle.

One application where this has been found to be a particular problem is in the storage of empty bottles.

Where bottles are filled in an in-line filling facility, it is not uncommon for the production of the bottles to lag behind the filling apparatus. In such cases, a buffer supply of bottles can be supplied from pre-manufactured bottles housed in a silo. Such storage inevitably leads to considerable external loads being experienced (especially by bottles at the bottom of the silo).

It is an object of the present invention to provide a bottle which has improved resistance to side wall crushing on the application of external side loads.

WIWWN

I

I

S 44

A

In accordance with the present invention, there is provided a thermoplastic bottle comprising a neck portion, a shoulder portion, a biaxially oriented body wall portion and a base extending from the lowest extremity of said body wall portion, said body wall portion including at least one circumferential groove which is adapted to increase the resistance of the said body wall portion to external side loads, said groove or grooves being symmetrical and each comprising a convex first section, a concave second section and a convex third section, the said concave second section being connected at either end to the first and third sections of the groove respectively and wherein the first, second and third sections each have a profile of separate areas of similar radial extent.

Preferably, the length of the sections of the body wall portion divided by the said groove/s are approximately the same.

For example, when a single groove is utilized, it is preferred that the circumferential groove be horizontal (ie. perpendicular to the axis of the bottle) and be located equidistant from the top and bottom of the body wall portion.

The shape and depth of the groove play an important role in the commercial utility of the bottle. If the groove is too wide, it can function in a concertina fashion leading to bottle growth (under carbonation pressure) and shrinkage (for example upon stacking). As this area of the bottle is usually 20 utilized for labelling any significant height variation after labelling can lead to label damage.

On the other hand, if the groove is too narrow, it will not lend itself to any significant improvement in the side wall strength. To a certain extent, the size of the groove appropriate for the particular bottle will depend on the bottle's size. In a bottle having capacity of between 1.0 to 2.0 litres, it is preferable that the groove be between 4 to 6 mm wide and between 1 to 2 mm deep. Most preferably, it is about 5 mm wide and about 1.5 mm deep.

The thickness of the container side wall is, in such cases, usually on the order of 0.2 to 0.4 mm.

"i

-'I

4 curved) and a third section which is agai ex; the three sections running into each o create a groove of the desired width a Preferably, the groove is symmetrica s e first, second and third sections each -^hM -M S g miE ci The neck portion, shoulder portion and base of the container may be varied in shape and size in accordance with known bottle technology. Preferably, the bottle has a base configuration comprising a number of separate legs and feet so that the bottle is self standing.

Thermoplastics useful in manufacturing bottles having the circumferential groove/s of the present invention include polyethylene terephthalate, acrylonitrile/styrene/methyl-acrylate copolymer, acrylonitrile/ethylene/methylacrylate copolymer, methacrylonitrile copolymers and similar such materials known in the art. Polyethylene terephthalate is the material of first choice given its known high tensile strength and relatively low creep characteristics.

Bottles made in accordance with the present invention may be formed using existing blow moulds modified simply by the inclusion of an appropriately shaped circumferential bead or beads at the appropriate locations in the blow mould.

The invention is hereafter described in greater detail with respect to a preferred embodiment which is illustrated in the accompanying drawings in which:- Figure 1 is a perspective view of a bottle made in accordance with the present invention; and Figure 2 is a cross-sectional view of the groove.

With reference to Figure 1, there is depicted a thermoplastic bottle 1 comprising a neck portion 2, a shoulder portion 3, a body wall portion 4 and a base A screw thread finish 6 is provided on the neck 2 so to receive and retain an appropriate closure. Base comprises five separate legs 7 which extend from the lowest portion 8 of the body side wall 4. The bottle rests on separate feet 9 which are located radially

V

I.

ITC~

5: inwardly from the body wall portion 4.

A horizontal circumferential groove 10 is centrally located so that the centre of the groove is substantially equidistant from the top 11 and the bottom 8 of the body wall portion 4. In a container having a volume of between to 2.0 litres of this shape, it is preferred that the groove have a width 12 of about 5.2 mm and a depth 13 of about 1.5 mm.

The preferred cross-section of the groove can be seen in greater detail in Figure 2 which depicts the cross-section of the groove. The groove is comprised of three separate sections 10A, 10B and 10C. The first section 10A, is generally convex in shape, the second section 10B is generally concave shape and the third 15 section 10C is again generally convex. In this embodiment, sections 10A, 10B and 10C each have the profile and cross section of an arc having a radius of curvature of about 1.5 mm.

It has been found that the inclusion of one or more 20 grooves in the body wall portion significantly strengthens this side wall for resisting external side loads such as *those encountered when storing empty bottles in a silo or 1 the like. The groove as described in the preferred embodiment has been found to give to the bottle excellent resistance to bottle growth under normal carbonation pressures whilst lending to crush resistance.

It should be understood that various modifications and additions to the construction of the bottle hereinbefore described are possible without departing from the spirit or ambit of the present invention as defined in the following claims.

Claims (13)

1. A thermoplastic bottle comprising a neck portion, a shoulder portion, a biaxially oriented body wall portion and a base extending from the lowest extremity of said body wall portion, said body wall portion including at least one circumferential groove which is adapted to increase the resistance of the said body wall portion to external side loads, said groove or grooves being symmetrical and each comprising a convex first section, a concave second section and a convex third section, the said concave second section being connected at either end to the first and third sections of the groove respectively and wherein the first, second and third sections each have a profile of separate areas of similar radial extent..

2. A thermoplastic bottle as defined in claim 1 wherein apart from said circumferential groove or grooves the surface of the said body wall portion is 15 substantially smooth.

S, A thermoplastic bottle as claimed in either one of claims 1 or 2 wherein said groove or grooves are each perpendicular to the axis of the bottle.

4. A thermoplastic bottle as claimed in any one of the previous claims wherein the capacity of the bottle is between 1.0 to 2.0 litres and the groove or grooves have a width of between 4 to 6 mm and a depth of between 1 to 2 mm.

A thermoplastic bottle as claimed in claim 4 wherein said bottle has a capacity of approximately 2.0 litres.

6. A thermoplastic bottle as claimed in claim 4 wherein said bottle has a *I single groove having a width of about 5.2mm and a depth of about

7. A thermoplastic bottle as claimed in any one of claims 4 to 6 wherein said body wall portion is between about 0.2 to 0.4 mm in wall thickness.

8. A thermoplastic bottle as claimed in claim 7 wherein the body wall portion is about 0.3 mm in wall thickness.

9. A thermoplastic bottle as claimed in any one of the previous claims wherein said body side wall is divided by said groove or grooves into a number of separate wall sections of approximately equal surface areas.

A thermoplastic bottle as claimed in claim 8 wherein said body wall is divided into two separate sections of approximately equal surface area by a single groove located equidistant between the top and bottom of the body i 1)r~ Mv~ .I: -7- wall portion.

11. A thermoplastic bottle as claimed in any one of the previous claims wherein said first, second and third sections each have a radius of curvature of about 1.5 mm.

12. A thermoplastic bottle as claimed in any one of the previous claims wherein said bottle is made from polyethylene terephthalate.

13. A thermoplastic bottle as substantially as hereinbefore described with particular reference to what is shown in the drawings. DATED: 13 October, 1994 PHILLIPS ORMONDE FITZPATRICK Attorneys for: r. ACI OPERATIONS PTY. LTD. j i 15 ^^L 1366W r i I_ I ABSTRACT A thermoplastic bottle comprising a neck portion, a shoulder portion, a biaxially oriented body wall portion and a base extending from the lowest extremity of said body wall portion wherein said body wall portion comprises at least one circumferential groove which is adapted to increase the resistance of the said body wall portion to external side loads. CI c t .1 I t