WO2008059256A9 - Procédé et appareil pour fabriquer un contenant dont la base s'adapte à la pression - Google Patents

Procédé et appareil pour fabriquer un contenant dont la base s'adapte à la pression

Info

Publication number
WO2008059256A9
WO2008059256A9 PCT/GB2007/004365 GB2007004365W WO2008059256A9 WO 2008059256 A9 WO2008059256 A9 WO 2008059256A9 GB 2007004365 W GB2007004365 W GB 2007004365W WO 2008059256 A9 WO2008059256 A9 WO 2008059256A9
Authority
WO
WIPO (PCT)
Prior art keywords
container
preform
pressure
cavity
rim
Prior art date
Application number
PCT/GB2007/004365
Other languages
English (en)
Other versions
WO2008059256A2 (fr
WO2008059256A3 (fr
Inventor
Robert James Blakeborough
Original Assignee
Plastic Can Company Ltd
Robert James Blakeborough
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Plastic Can Company Ltd, Robert James Blakeborough filed Critical Plastic Can Company Ltd
Publication of WO2008059256A2 publication Critical patent/WO2008059256A2/fr
Publication of WO2008059256A3 publication Critical patent/WO2008059256A3/fr
Publication of WO2008059256A9 publication Critical patent/WO2008059256A9/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D79/00—Kinds or details of packages, not otherwise provided for
    • B65D79/005—Packages having deformable parts for indicating or neutralizing internal pressure-variations by other means than venting
    • B65D79/008—Packages having deformable parts for indicating or neutralizing internal pressure-variations by other means than venting the deformable part being located in a rigid or semi-rigid container, e.g. in bottles or jars
    • B65D79/0081—Packages having deformable parts for indicating or neutralizing internal pressure-variations by other means than venting the deformable part being located in a rigid or semi-rigid container, e.g. in bottles or jars in the bottom part thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/42—Component parts, details or accessories; Auxiliary operations
    • B29C49/64—Heating or cooling preforms, parisons or blown articles
    • B29C49/6409—Thermal conditioning of preforms
    • B29C49/6436—Thermal conditioning of preforms characterised by temperature differential
    • B29C49/6445—Thermal conditioning of preforms characterised by temperature differential through the preform length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B29C49/06—Injection blow-moulding
    • B29C49/061—Injection blow-moulding with parison holding means displaceable between injection and blow stations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C69/00—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C69/00—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore
    • B29C69/02—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore of moulding techniques only
    • B29C69/025—Deforming articles in a simpler intermediate shape without internal stresses for packaging transporting or storage and reshaping and fixing the original configuration on the place of use
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
    • B65D1/02—Bottles or similar containers with necks or like restricted apertures, designed for pouring contents
    • B65D1/0223—Bottles or similar containers with necks or like restricted apertures, designed for pouring contents characterised by shape
    • B65D1/0261—Bottom construction
    • B65D1/0276—Bottom construction having a continuous contact surface, e.g. Champagne-type bottom
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
    • B65D1/12—Cans, casks, barrels, or drums
    • B65D1/14—Cans, casks, barrels, or drums characterised by shape
    • B65D1/16—Cans, casks, barrels, or drums characterised by shape of curved cross-section, e.g. cylindrical
    • B65D1/165—Cylindrical cans
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B11/00—Making preforms
    • B29B11/06—Making preforms by moulding the material
    • B29B11/08—Injection moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B11/00—Making preforms
    • B29B11/14—Making preforms characterised by structure or composition
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
    • B29C2035/0822—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using IR radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/16—Cooling
    • B29C2035/1658—Cooling using gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B29C2049/023—Combined blow-moulding and manufacture of the preform or the parison using inherent heat of the preform, i.e. 1 step blow moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/0715—Preforms or parisons characterised by their configuration the preform having one end closed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/072—Preforms or parisons characterised by their configuration having variable wall thickness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/073—Preforms or parisons characterised by their configuration having variable diameter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/076—Preforms or parisons characterised by their configuration characterised by the shape
    • B29C2949/0761—Preforms or parisons characterised by their configuration characterised by the shape characterised by overall the shape
    • B29C2949/0762—Conical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/076—Preforms or parisons characterised by their configuration characterised by the shape
    • B29C2949/0768—Preforms or parisons characterised by their configuration characterised by the shape characterised by the shape of specific parts of preform
    • B29C2949/077—Preforms or parisons characterised by their configuration characterised by the shape characterised by the shape of specific parts of preform characterised by the neck
    • B29C2949/0771—Wide-mouth
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/076—Preforms or parisons characterised by their configuration characterised by the shape
    • B29C2949/0768—Preforms or parisons characterised by their configuration characterised by the shape characterised by the shape of specific parts of preform
    • B29C2949/077—Preforms or parisons characterised by their configuration characterised by the shape characterised by the shape of specific parts of preform characterised by the neck
    • B29C2949/0772—Closure retaining means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/22—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at neck portion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/24—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at flange portion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/26—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at body portion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/28—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at bottom portion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/3024—Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B29C49/06—Injection blow-moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/071—Preforms or parisons characterised by their configuration, e.g. geometry, dimensions or physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/42—Component parts, details or accessories; Auxiliary operations
    • B29C49/42394—Providing specific wall thickness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/10—Polymers of propylene
    • B29K2023/12—PP, i.e. polypropylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2027/00—Use of polyvinylhalogenides or derivatives thereof as moulding material
    • B29K2027/06—PVC, i.e. polyvinylchloride
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • B29L2031/7158—Bottles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • B29L2031/7158—Bottles
    • B29L2031/716—Bottles of the wide mouth type, i.e. the diameters of the bottle opening and its body are substantially identical

Definitions

  • This invention relates to a method of and apparatus for making a container with a pressure accommodating base, and to a container made thereby.
  • the invention is particularly suitable for the manufacture of wide-mouth containers in the nature of cans or pots, preferably with lids, from polyethylene terephthalate (PET) , though it is not limited to such manufacture.
  • PET polyethylene terephthalate
  • the term "wide-mouth” is well understood by the skilled person; in the industry it is understood to relate to a container with a mouth greater than approximately 35mm.
  • “Narrow-mouth” on the other hand is understood to relate to a container with a mouth less than approximately 35mm.
  • the sidewall of the container can collapse or buckle inwards some time after the containers have been filled and sealed. This is unacceptable because labels are often applied to the sidewall and deformation of the wall can render the label illegible or the container aesthetically unappealing.
  • the buckling is due to a decrease in pressure (relative to atmospheric pressure) or partial vacuum inside the container.
  • pressure relative to atmospheric pressure
  • partial vacuum inside the container.
  • FIG. 12a and 12b of the present application show side sectional views of the base of a container 300 of WO2004/106175, first in the configuration as moulded (Fig. 12a) and secondly in a configuration after responding to vacuum related forces (Fig. 12b) .
  • the figures are described in full detail in WO2004/106175.
  • the structure has an inversion ring 302 and further requires a central push-up 301 generally in the shape of a truncated cone.
  • the inversion ring forms a relatively large part of the base, whilst the central push-up 301 forms a relatively small part of the base.
  • the base of containers that can respond to vacuum related forces must have a specific distribution of material that provides flexibility in the correct places.
  • a central push-up 301 is required to obtain this distribution of material.
  • the pushup 301 is required due to the nature of blow moulding narrow mouth containers .
  • a typical narrow mouth container e.g. a bottle
  • a tubular, or test-tube-like, preform is used, which is heated prior to insertion into the mould. Initially, the preform expands vertically down the mould (i.e.
  • US Patent No. 4,880,129 describes a thermally processable food container.
  • This container is thermoformed: a completely different technique to that used in the present invention; essentially it is stamped out of a hot sheet.
  • the bottom wall is fully flexible to accommodate the short-term increase in internal pressure over external pressure that arises during thermal processing of food containers.
  • the bottom wall is able to distort into a bulged condition as the temperature and thus the internal pressure rises, and then revert to its normal concave condition at the conclusion of thermal processing when the internal pressure falls as the container is cooled once more to room temperature.
  • the preferred embodiments take the form of a wide-mouth container (i.e. as defined previously with reference to the understanding within the blow-moulding industry) having a body of similar or wider diameter and a rim defining an opening for the container, the container being made of a material which is susceptible to deformation when heated.
  • the container can be manufactured in a multi-step process, the first step comprising injection moulding in an injection-moulding apparatus a preform which has a rim formed at its mouth and a continuous body-forming portion extending across the preform from the inner periphery of the rim.
  • the preform is heated such that it has a specified temperature profile.
  • the heating is carried out using infra-red heaters.
  • the step of heating can also be combined with a step of cooling certain portions of the preform, preferably using a stream of gas.
  • the preform may be extracted from the injection mould while it is still hot from the injection moulding process and transferred either directly to the final step, or via an intervening conditioning step in which the hot preform may optionally be exposed to preferential heating (or cooling) .
  • the preform is placed in a moulding cavity of a blow moulding apparatus with the preform being located by means of the rim.
  • the body-forming portion expands in the cavity to form the side and bottom walls of the container.
  • the combination of the shape and thickness of the body-forming portion of the preform, the temperature profile of the preform, and the shape of the moulding cavity of the blow moulding apparatus cause the bottom wall of the container to have a central rigid substantially-flat portion and an annular relatively flexible portion circumscribing the central rigid portion, the two portions being directly adjacent and integrally connected.
  • directly adjacent it is meant that there are no intervening portions between the central rigid substantially-flat portion and the annular relatively flexible portion.
  • directly adjacent is meant to encompass the case where there is a gradual taper in thickness between the rigid substantially-flat portion and the annular relatively flexible portion.
  • the ratio of the thickness of the central rigid portion to the thickness of the annular relatively flexible portion is at least 2.3:1.
  • this ratio is between 3.3:1 and 4.3:1.
  • the ratio of the diameter of (or dimension across) the central rigid portion to the ratio of the diameter of (or dimension across) the base of the container is at least 0.5:1, and the ratio of the radial extent of (or dimension across) the annular flexible portion to the total diameter of (or dimension across) the base of the container is at most 0.2:1.
  • the flexible portion is arranged such that the central rigid portion can be urged into any position (i.e. any one of a continuum or plurality of positions) between a first lowered position and a second raised position due to flexing of the flexible portion.
  • the base of the container is not bi-stable (i.e. it is not stable in only two configurations).
  • the sealed container can accommodate changes in pressure within the container relative to atmospheric pressure.
  • the container is preferably provided with a lid which conforms with the upper surface of the rim.
  • the lid sealingly engages the rim of the container, preferably comprising two sealing elements, one on the top and the other at the side of the portion of the lid engaging the rim.
  • a flap may be provided at the side of the lid to assist in its removal.
  • Figure 1 is a side sectional view through a container embodying the present invention
  • Figure 2 is a sectional detail through the rim of the container of Figure 1;
  • Figure 3 is a side sectional detail through the base of the container of Figure 1, with the base in its lowered position as moulded;
  • Figure 4 is a side sectional detail through the base of the container of Figure 1, with the base in its raised position;
  • Figure 5 is a side sectional detail through the base of the container of Figure 1, showing thickness, in mm, of the base and sidewall;
  • Figure 6 is a side sectional view through an injection moulded preform used in the manufacture of the container of Figure 1;
  • Figure 7 is a side section view through an injection station of a one-stage machine illustrating the manufacture of the preform;
  • Figure 8 is a diagrammatic side section view of the heating station of a reheat blow moulding machine used to change the temperature profile of the preform
  • Figure 9 is a perspective view of the heating station of a reheat blow moulding machine used to change the temperature profile of the preform
  • Figure 10 is a sectional view through a blow mould illustrating the beginning of the formation of the container from the preform
  • Figure 11 is a side sectional view through a second container embodying the present invention
  • Figure 12a and Figure 12b are side sectional views of the base of the container of WO2004/106175, included for comparative purposes.
  • Figure 1 is a side sectional view through a finished wide-mouth container 1 embodying the invention.
  • the container may be of generally cylindrical shape as shown here, or may be square or other shape according to market demand with sides 20 and a base 2.
  • the base has a central substantially flat (or substantially- planar) rigid disc 4, which is circumscribed by an annular relatively flexible region 5.
  • the annular flexible region 5 is thinner than the thick central rigid disc 4, which causes the difference in flexibility.
  • the thick central rigid disc 4 is supported by the annular flexible region.
  • a rim 3 defines the mouth of the container.
  • substantially flat it is meant that the portion is substantially planar (i.e. having a substantially two dimensional characteristic - the third dimension being substantially smaller than the other two) .
  • the term substantially flat as used in the present invention encompasses a central rigid portion having some slight doming (as shown) , which provides additional strength.
  • the base construction is such that the central rigid disc can move to one of a plurality of positions between a lowered position (as moulded) and a raised position. This allows the volume of the container to decrease in response to a decrease in pressure in a sealed container. Thus, if the pressure decreases (e.g. because of the reasons outlined previously) , the base can move to the raised position, accommodating the pressure in the container and effectively equalising it with atmospheric pressure and thus preventing the sidewalls from collapsing.
  • Figure 3 which shows the lowered base position (as moulded)
  • Figure 4 which shows the raised base position in response to a decrease in pressure.
  • the base of the container may take one of a plurality of positions (not 5. shown) in response to different pressure changes.
  • the shape of the flexible region 5 is such as to allow flexing in response to changing pressure differences between the inside and outside of the container and thereby prevent vacuum-induced collapse of the container sidewall 20.
  • the base As0 moulded and shown in Figure 3, proceeding inwardly from the side 20, the base comprises a substantially flat portion 6 which forms the peripheral contact ring which rests on the surface upon which the container stands.
  • a concave portion 7 as seen from outside the container5 and this in turn by a convex portion 8 which merges into the central substantially-flat relatively rigid disc 4.
  • the portions 4, 7 and 8 provide a somewhat concave region when seen from below. Flexure is accommodated by the disc 4 moving upwards so that the portion 8 merges into the concave0 portion 7 and itself becomes concave, as shown in Figure 4.
  • the portions 7,8 operate as an inversion ring, or in a bellows-like manner.
  • the base of the container has the correct distribution of material, i.e. the correct 5 thickness.
  • the annular flexible region must be thin enough to flex at a pressure which is below that at which the sidewalls collapse.
  • the annular flexible region cannot be too thin, as this would lead to sagging of the base when it is filled.
  • the central disc must0 not move so easily that it could come into contact with the ground if the container was accidentally dropped.
  • Figure 5 shows the desired side and base thickness (in millimetres) of a 1 US Gallon (3785ml) paint can embodying the present invention. It has a diameter of 168mm.
  • The5 skilled person will appreciate that the desired base thickness can be adjusted for containers with different diameters; for example, for larger containers, the central disc and annular flexible regions may be thicker to support a larger mass of contents. In general, the best dimensions for any given application (container size and type of contents) can be determined empirically. However, the present inventors have found that a base with the thickness of Figure 5 performs well in containers of this diameter having volumes from 2500ml to 5000ml.
  • the central rigid disc region preferably has a thickness of between 1.5 and 3 mm.
  • the lesser figure relates to containers with diameters between 100 and 120 mm, while the greater relates to containers with diameters between 150 and 180 mm, with other sizes pro rata.
  • the annular flexible region preferably has a thickness of between 0.3 and 0.7 mm.
  • the ratio of the thickness of the central rigid portion to the thickness of the annular relatively flexible region in a particular container is at least 2.3:1, more preferably between 3.3:1 and 4.3:1. It will be understood that the transition from the central rigid disc to the annular flexible portion can be a continuous transition; the thickness of the base can taper smoothly from the thicker central rigid disc to the relatively thinner annular flexible portion.
  • the boundary of the central rigid disc and the annular flexible portion may be defined as the point at which the thickness of the base is half-way between the thickness of the central rigid disc and the thickness of the annular flexible portion.
  • the central substantially-flat relatively rigid disc is directly adjacent and integrally connected to the annular relatively flexible portion.
  • the ratio of the diameter of (or dimension across) the central rigid disc to the diameter of (or dimension across) the base of the container is preferably at least 0.5:1. In the embodiment shown in Figure 1 the ratio is about 0.52:1.
  • the central rigid disc forms a major part of the diameter of the base.
  • the ratio of the radial extent of the annular relatively flexible portion to the total diameter of the base of the container is preferably at most 0.2:1.
  • the annular relatively flexible portion constitutes a relatively small part of the diameter of the base.
  • the central rigid portion and the annular relatively flexible portion could each be substantially uniform in thickness. However, it is preferable that there are no abrupt changes in thickness, as these could lead to a weak point in the base. Thus, the central rigid portion tapers gradually into the annular relatively flexible region.
  • Figure 2 is a sectional detail through the rim 3 of the container 1.
  • the rim 3 has, from the inside, an upstanding flange 21 defining the inside of a U-shaped channel 22 whose radially outer side 23 is lower than the flange 21.
  • a horizontal flange 24 projects outwardly from the side 23 from the latter' s smoothly rounded top 25 and a skirt 26 depends from its outer edge. Approximately half-way down the skirt there may be a small annular outwardly- extending rib 27 as shown in the figure.
  • the flange 21 has a slight inward taper towards the top, and the channel 22 is slightly flared.
  • ribs 29 At regular intervals around the rim 3 there are slim ribs 29 in planes radial to the axis of the container. They are shown in cross hatching to distinguish them from the rest of the rim with which they are integrally moulded. These ribs enhance the strength of the rim, and typically between eight and twelve ribs 29 (depending upon the diameter of the rim 3) may be included. For clarity the ribs 29 are not shown in the other figures.
  • the sides 20 contact the bottom of the skirt 26 to form a box section 30, which provides further strength to the rim.
  • the lid can be based on the lid described in International Patent Application No. WO00/46118.
  • the method of manufacturing the container of Figure 1 will now be described.
  • the manufacturing method is based on that described in International Patent Application No. WO97/19801.
  • the shape of the rim is a modification of the rims described in International Patent Application No. WO00/46118. Reference may be made to both these applications for further details and variations concerning the design.
  • the first stage of the method is to form a preform 15 as shown in Figure 6.
  • the preform includes a fully formed rim 3 as described above.
  • the wall 20 of the body of the container is not formed at this time, but instead the preform includes a continuous dished or bowl-shaped body- forming member 120 which extends across the preform from the inner periphery 21 of the rim, but which is of reduced size compared with its final form.
  • the body-forming member 120 of the preform does not contact the bottom of the skirt 26 as in the finished container, and therefore the box section 30 referred to in Figure 2 has yet to be formed.
  • the shape of the body-forming member 120 can be anything from approaching a flat membrane to a substantially conical shape.
  • the thickness of the body-forming member 120 is important, as it will at least partially determine the thickness of the final sidewalls and bottom wall.
  • the body-forming member 120 should preferably be of thickness of between 2 and 4 mm.
  • the region which will form the sidewall should be of substantially uniform thickness, and preferably the body-forming member should be without abrupt changes in thickness.
  • a computer running conventional design software is normally used to calculate the dimensions of the preform based on the dimensions of the finished container, the stretching characteristics of the specific material to be used, and the desired material distribution.
  • the preform is formed by injection moulding on an injection moulding machine. Injection moulding apparatus are very well known and thus a detailed description of such apparatus need not be given here.
  • the rim of the preform is fully formed in this operation and adopts the shape required in the final container.
  • the use of injection moulding allows the rim and body-forming portion to be formed with high accuracy, which is necessary respectively for good sealing of the lid and for achieving the optimal distribution of material in the bottom wall of the finished container.
  • the method can also comprise providing a lid which conforms with the upper surface of the rim.
  • the lid can also be injection moulded and can be based, for example, on the lid described in International Patent Application No. WOOO/46118.
  • preform and eventual container are assumed to be in conventional orientation, that is with the mouth at the top and the base at the bottom.
  • the terms “up”, “down”, “raised” and “lowered” and their derivatives should therefore be construed in this sense although in actual fact the orientation of the preform or container may be different from this.
  • the manufacturing process can proceed in either a one-stage or two-stage process.
  • preforms are injection moulded, removed from the injection mould while they are still hot from the injection moulding process, if necessary the temperature profile can be adjusted at a conditioning station, and the hot preforms are then blown into finished containers in a single continuous process on one machine.
  • a section through the injection station of a typical one-stage machine is shown in Figure 7.
  • the injection mould has two main sections, namely a lower section formed by a cavity insert 42 and an upper section formed by a two-part inner preform core pin 44 and an outer preform core pin section 46.
  • Neck splits 48 are also provided, carried by neck split carrier plates 50, on the machine carousel 52. Plastics material is injected through an injection orifice 54 in the cavity insert 42 at the bottom centre of the preform 15.
  • the preform is designed in such a manner that a straightforward vertical movement of the central mould core (pin 44 and 46) will allow removal of the preform from the mould. There are no undercuts or slides in the construction of either the core or the cavity.
  • the preforms may be cooled to room temperature after discharge from the injection moulding machine and if desired may be stored or shipped to a completely different location for reheating and blowing to give the finished container.
  • the shape of the preform enables them to internest or- stack with other like preforms, which allows for more efficient storage and transportation.
  • the preforms are easy to separate, because individual preforms can be grasped easily.
  • the preforms When the preforms are to be moulded to form the finished containers, they must first be reheated, as illustrated in Figures 8 and 9, so they have the correct temperature profile. Reheating is achieved using an array of infra-red lamps 201-208. These lamps allow the preform 15 to be heated in specific places in order to achieve the correct distribution of material in the finished container.
  • the preform is held in front of the infrared lamps by a clamp 209, which engages with the preform 15 on its rim 3.
  • the clamp 209 revolves around a central axis 210.
  • the preform rotates about its longitudinal axis, evenly exposing the body-forming portion 120 of the preform to the heaters.
  • the preform is held in front of the heaters for approximately 72 seconds, although a person skilled in the art of reheat blow moulding would appreciate that this time can be adjusted in order to achieve the correct distribution of material in the finished container.
  • the intensity of the lamps must be carefully adjusted.
  • the present inventors have found that the intensities displayed in Table 1 below have been found to give a good distribution of material in the finished product.
  • the skilled person would again appreciate that the lamps' intensities can be adjusted in order to achieve the correct distribution of material in the finished container.
  • the skilled person would be able to alter the intensities accurately based on the appearance of the finished container.
  • the preform After heating has taken place, the preform should have a temperature of approximately 102 0 C (measured halfway down the preform sidewall immediately after the preform has been heated) . This temperature is approximate and could be adjusted by the skilled person.
  • the required temperature profile can be defined with reference to the heating pattern as described in Table 1, with further adjustments understood to be possible by the skilled person. Broadly, more heat is applied to the upper part of the body-forming portion (i.e. near the rim) and towards the very bottom of the body-forming portion. Thus, these areas have a higher temperature after heating, will deform more readily during the blow moulding, and will be thinner as a result.
  • the temperature profile of the preform achieved by the aforementioned heating is important in determining the distribution of material in the finished container .
  • Figure 9 illustrates the automated heating process in a perspective view.
  • the preform 15 is seen to be held by the revolving clamp 209, engaging with the preform rim 3.
  • This clamp moves along the length of the infra-red lamps 201-208 such that the preform is exposed for approximately 72 seconds and is heated to a temperature of approximately 102 0 C.
  • the preform In addition to heating the preform as described above, it is also possible to cool certain portions of the preform in order to achieve the correct temperature profile.
  • the cooling can be achieved by passing a directed gas current at certain portions of the heated preform during the heating process.
  • the directed gas current is a jet of pressurized air.
  • the gas can be directed through openings 212 to cool the body-forming portion 120 of the preform, and longitudinal slit 211 to cool the rim 3 shown in Figure 9.
  • a blow moulding machine is one type of pressure moulding machine; a less preferred alternative would be to employ a machine that uses suction rather than blowing.
  • Blow moulding machines, and methods of blow moulding are well known in the art and are describes, for example, in International Patent Applications WO97/19801, WO00/46118 and WO2004/71745.
  • the hot and pliable preform is then transferred to the blow moulding station 60, shown in Figure 10.
  • This comprises a cavity 61 defined at the sides by two moveable mould halves 62 and 63 with preform retention and locating pieces 71 and 72 at the top and at the bottom by a moveable base or punt 64.
  • the cavity 61 has a shape which conforms with the shape of the finished container.
  • the cavity 61 has a base 64 which has a central disc region which is substantially planar which will cause the central rigid disc portion 4 to be formed, and also an annular ridge 68 circumscribing the central disc, which will cause the formation of the annular flexible portion 5 as described previously.
  • the top of the cavity is defined by a clamp 209 which has a circular opening through which an axially vertically moveable central stretch rod 66 can be lowered into the open top of the preform 15 such that it engages the body-forming portion 120 of the preform 15. As it descends it causes mechanical downward stretching of the body-forming section.
  • the part of clamp 20-9 which engages with the preform rim 3 may be flat as shown in this simplified view, or preferably will be profiled to closely match the shape of U-shaped channel 22.
  • the sequence is that first the two blow mould halves 62, 63 with preform retention and locating pieces 71 and 72 close around the pliable preform 15 supported by the preform carrier 209. Then the stretch rod 66 is lowered to force the material 120, which is to constitute the container walls, towards the base 64 of the mould cavity 61. Simultaneously, compressed air is introduced through the middle of the preform carrier 209 into the preform. This causes the plastics material at the top of the preform to move outwardly until it contacts the side of the blow mould cavity, contacting the bottom of the skirt 26 as it does so, thus forming a box section in the rim.
  • an aneurysm forms that rapidly inflates until a proto-container, slightly smaller than the mould cavity, has been formed.
  • higher pressure compressed air is introduced to form the finished container by compressing the still-soft plastics material of the preform hard against the metal sides of the blow mould. This continues to be assisted by the mechanical stretching caused by the stretch rod 66.
  • the stretch rod 66 is also used to centre the gate (the central or bottom point) of the preform in the bottom of the container. The amount of mechanical stretching imparted by the stretch rod 66 is actually small compared to the stretching caused by the compressed air.
  • the shape of the mould cavity 61 is such as to impart the desired shape to the container side walls 20 and bottom wall 2.
  • the high pressure air is exhausted and the blow mould opens and the container is then lifted out by means of the rim 3.
  • the metal sides of the blow mould may optionally be chilled to help cooling of the plastics material.
  • Figure 11 is a side sectional view through a finished wide-mouth container which is a second embodiment of the invention.
  • the container may be of generally cylindrical shape as shown here, or may be square or other shape with sides 20 and a base 2.
  • the base has a central rigid substantially-flat disc 4, which is circumscribed by an annular relatively flexible region 5.
  • the annular flexible region 5 is thinner than the thick central rigid disc 4, which causes the difference in flexibility.
  • the thick central rigid disc 4 is supported by the annular flexible region 5.
  • a rim 3 defines the mouth of the container.
  • the central rigid disc can move to any one of a plurality of positions between a lowered position (as moulded) and a raised position, allowing for accommodation of changes in pressure. This movement is similar to that illustrated in Figures 3 and 4.
  • the shape of the flexible region 5 is such as to allow flexing in response to changing pressure differences between the inside and outside of the container and thereby prevent vacuum-indexed collapse of the container sidewall 20.
  • the base comprises a substantially flat portion 106 which forms the peripheral contact ring which rests on the surface upon which the container stands. This is followed by a concave portion 107 and this in turn by a convex portion 108, followed by a further concave portion 109 which merges into the central relatively rigid disc 4. Flexure is accommodated by the disc 4 moving upwards so that the portion 108 merges into concave portions 107 and 109, itself becoming concave. Thus the portions 107, 108 and 109 operate in a bellows-like manner.
  • the shape of the flexible region is designed to achieve the correct distribution of material in the finished container to achieve the required amount of flexing whilst retaining sufficient strength. This design is particularly good at achieving the required flexibility in region 5 in smaller diameter containers (up to 120 mm) , but can also be used for larger diameter containers (greater than 120 mm) .
  • the containers are preferably made of a plasties material, by which it is meant any of various organic compounds produced by polymerization, capable of being moulded, extruded, cast into various shapes and films, or drawn into filaments .
  • Containers are more preferably made from polyethylene terephthalate (PET) , for which the process is particularly suitable.
  • thermoplastic resins may however be used, including polyethylene naphthalate (PEN) , also PET and PEN blends and other blow mouldable plastics including polyvinyl chloride (PVC) , polycarbonate, and polypropylene (PP) .
  • PEN polyethylene naphthalate
  • PVC polyvinyl chloride
  • PP polypropylene
  • any material suitable to deformation when heated may be used, but the method is particularly advantageous with PET etc.
  • PET resins are characterised by their intrinsic viscosity (IV) , which is a number related to the molecular chain length (the longer the molecule, the higher the IV and the better the mechanical properties) .
  • IV intrinsic viscosity
  • Resins having intrinsic viscosities in the range of 0.76-0.84 have been found to be most preferable for production of containers embodying the present invention.
  • the containers can be formed as pails, buckets, or cans and are particularly suitable for enclosing solvent- based contents for storage for long period without solvent loss. They may, in particular, be used as cans, especially lever-lid cans, for paint and other coating materials.
  • the container itself is made as a unitary element without the need for welds, which are costly and can be unreliable.
  • the containers can be formed accurately of PET, which requires blow moulding to give the biaxial stretching necessary for optimum strength.
  • the base of the container is designed to equalize a pressure differential between the interior of the container (when sealed with a lid) and the atmosphere by decreasing the volume of the container.
  • the base prevents the sidewalls from collapsing, which would be unacceptable for aesthetic reasons and would prevent a label on the container from being intelligible.
  • the pressure equalising base means stiffening ribs are not required in the container body, which would otherwise be visible beneath a label.
  • the design of the base allows for controlled movement of the central rigid portion; the central rigid portion will not flop about (i.e. move to multiple positions in multiple directions) , but is substantially confined to movement in one vertical direction between a raised or lowered position. Yet due to the size of the central rigid portion - the central rigid portion forming a large part of the diameter of or dimension across the base - the central rigid portion will readily move up when the external pressure exceeds the internal pressure before the container sidewall 20 begins to collapse.
  • the base embodying the present invention is sufficiently strong that it will not sag or deform when the container is filled.
  • the base design illustrated not only provides the above advantageous features, but also does so with the minimum excess material.
  • no central push-up is required in the base.
  • Such a push-up would lead to effectively wasted material; thus, costs are minimised.
  • the design of the base is made possible by the method embodying the present invention.
  • the present method can achieve the requisite distribution of material with sufficient strength and flexibility without the need for a push-up portion.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Abstract

L'invention concerne un contenant (1) et un rebord (3) définissant une ouverture pour le contenant. Le contenant est fait d'une matière comme PET ou PEN et fabriqué par un procédé en plusieurs étapes. La première étape comporte le moulage par injection d'une préforme (15) dont l'embouchure est pourvue d'un rebord (3), et dont une partie forme un corps continu (120) s'étendant de la périphérie interne (21) du rebord et traverse la préforme. Dans l'étape finale, la préforme chaude est placée par soufflage (60) dans la cavité de moulage (61) d'un appareil de moulage, la préforme étant située dans la cavité de moulage (61) au moyen du rebord (3). La partie formant corps (100) s'étend dans la cavité pour former les parois latérales (20) et la paroi inférieure (2) du contenant. La combinaison de la forme et de l'épaisseur de la préforme (15), du profil de température de la préforme après chauffage et de la forme de la cavité de moulage (61) de l'appareil de moulage par soufflage amène la paroi inférieure (2) du contenant à avoir une partie sensiblement plate rigide, centrale (4) et une partie (5) à annulaire relativement souple circonscrivant la partie rigide centrale, les deux parties étant directement adjacentes et reliées d'un seul tenant. La partie souple (5) est disposée de telle sorte que la partie rigide centrale (4), par flexion de la partie souple, peut être poussée dans n'importe laquelle des positions d'un continuum de positions entre une première position abaissée et une seconde position surélevée. Le contenant scellé peut ainsi s'adapter à des changements de la pression intérieure par rapport à la pression atmosphérique.
PCT/GB2007/004365 2006-11-15 2007-11-15 Procédé et appareil pour fabriquer un contenant dont la base s'adapte à la pression WO2008059256A2 (fr)

Applications Claiming Priority (2)

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GB0622813.4 2006-11-15
GB0622813A GB2443807A (en) 2006-11-15 2006-11-15 Method and apparatus for making a container with a pressure accommodating base

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GB201008520D0 (en) 2010-05-21 2010-07-07 Brittpac Ltd Containers
GB2480557B (en) * 2010-05-21 2016-05-11 Brittpac Ltd Containers

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US4642968A (en) * 1983-01-05 1987-02-17 American Can Company Method of obtaining acceptable configuration of a plastic container after thermal food sterilization process
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US4894268A (en) * 1987-12-07 1990-01-16 Sonoco Products Company Stretch blow-molded polyethylene terephthalate wide mouth container and intermediate article
US5038947A (en) * 1989-08-24 1991-08-13 Plasticon Patents, S.A. Self-stabilizing base for pressurized bottle
JPH0694158B2 (ja) * 1990-10-26 1994-11-24 日精エー・エス・ビー機械株式会社 合成樹脂製の缶胴成形用プリフォーム及びそれを用いた合成樹脂製缶胴の製造方法
JP3044211B2 (ja) * 1998-09-25 2000-05-22 住友ゴム工業株式会社 合成樹脂製の耐圧広口容器および該容器の製造方法
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US6942116B2 (en) * 2003-05-23 2005-09-13 Amcor Limited Container base structure responsive to vacuum related forces

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WO2008059256A3 (fr) 2008-08-14
GB0622813D0 (en) 2006-12-27
GB2443807A (en) 2008-05-21

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