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
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/48—Moulds
• • 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
• • 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
  • B29C49/48—Moulds
  • B29C2049/4879—Moulds characterised by mould configurations
  • B29C2049/4892—Mould halves consisting of an independent main and bottom part
• • 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
  • B29C49/78—Measuring, controlling or regulating
  • B29C49/783—Measuring, controlling or regulating blowing pressure
  • B29C2049/7831—Measuring, controlling or regulating blowing pressure characterised by pressure values or ranges
• • 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
  • B29C49/78—Measuring, controlling or regulating
  • B29C49/783—Measuring, controlling or regulating blowing pressure
  • B29C2049/7832—Blowing with two or more pressure levels
• • 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
  • 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
  • B29C49/08—Biaxial stretching during blow-moulding
  • B29C49/10—Biaxial stretching during blow-moulding using mechanical means for prestretching
  • B29C49/12—Stretching rods
• • 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
  • B29C49/56—Opening, closing or clamping means
  • B29C49/5612—Opening, closing or clamping means characterised by bottom part movement

Definitions

• the invention relates to the manufacture of containers, such as bottles or pots, obtained by blow molding or stretch blow molding from thermoplastic blanks.
• a container To manufacture a container according to the blowing technique, it is first heated by a blank (whether a preform or an intermediate container having undergone a first blowing operation from a preform) to a temperature greater than the glass transition temperature of the constituent material of the blank.
• the blank is then introduced into a mold, and then the blank is blown by injecting a gas (such as air) under high pressure (generally greater than 30 bars).
• a gas such as air
• the stretch-blow technique consists in stretching the blank with a sliding rod in order to minimize the misalignment of the container and to make the distribution of the material as uniform as possible.
• the mold includes a wall defining a cavity for imparting its shape to the body of the container. This cavity is closed at a lower end by a mold bottom to give its shape to the bottom of the container.
• the containers undergo during the blowing a double molecular orientation: axial on the one hand, parallel to the general axis of the mold; radial on the other hand, perpendicular to the axis of the mold. This bi-orientation gives the containers a certain structural rigidity.
• thermofixation 2 649 035 (Sidel) and its US equivalent US 5, 145,632 consists in heating the wall of the mold, which confers on the container held in contact with it an additional rigidity due to the increase in the degree of crystallinity (it is called thermofixation) .
• thermofixation fails to resorb, except to provide unacceptable cycle times industrially.
• a technical solution has been proposed to increase the structural rigidity of the bottom, by increasing its rate of deformation. According to this solution, which may or may not be combined with a heat-setting, the container is first stretched beyond its final height before being completely blown to the correct height.
• the mold bottom is mounted axially movable relative to the wall of the mold.
• the mold bottom is placed in a low position and the container undergoes axial deformation by stretching until the elongation rod reaches the bottom of the mold.
• the mold bottom is then raised to the upper position and, while the blowing continues, the container is pressed against the mold bottom.
• This technique called boxing, allows, by stretching the bottom beyond its normal position, to increase its rate of deformation and thus its crystallinity.
• there is a decrease in the thickness of the bottom which not only allows to consider a decrease in the amount of material, but also to achieve a better heat setting.
• the boxing technique illustrated in particular in the European patent EP 1 069 983, however, is not without drawbacks.
• the main difficulty is to synchronize the ascending movement of the mold bottom with the blowing of the container. Indeed, if the drawing is constantly under control, via the positioning of the elongation rod, the blowing comprises uncertainties as to how the air bubble develops within the blank. More precisely, if we know the general profile of the development of the bubble, there may be variations of this profile from one container to another because of the unequal distribution of the material as well as the temperature. Also, raising the bottom of the mold too early can lead to insufficiently stretched bottom.
• the invention proposes a mold for the manufacture, by blow-molding from plastic blanks, of containers having a body and a bottom, this mold comprising a wall defining a cavity distributed around a main axis of the mold and comprising a lateral surface for conferring its shape to the body of the container, said wall having, in a lower part, an opening defining a passage for a mold bottom whose upper surface is intended to at least partly give its shape to the bottom of the container, in which mold, in any plane containing the axis of the wall: the ratio between a transverse dimension of an upper edge of the opening and a transverse dimension of a lower end of the lateral surface of the wall; is greater than 0.95, and
• the tangent to the lateral surface of the wall, at the lower end thereof, forms with the axis of the wall an angle less than or equal to 10 °.
• the ratio between the transverse dimension of the upper edge of the opening and the transverse dimension of the lower end of the side surface of the wall may be equal to 1, the wall being devoid of annular rim at its lower end.
• the wall has, around the opening, an annular rim having a radial upper surface, and in that the wall is devoid of connection fillet at the junction between the lateral surface and this radial upper surface.
• the mold further comprises a mold bottom having an upper surface forming an impression of a container bottom and a transverse dimension, measured at the edge of this upper surface, is equal, within the operating clearance, to the dimension transverse of the upper edge of the opening, this mold being mounted movable relative to the wall between a low position in which the mold bottom is spaced from the opening, and a high position in which the mold bottom closes the opening .
• the invention provides a plastic container, comprising a body and a bottom having a predetermined transverse dimension, and having a connection fillet at the junction between the body and the bottom, container in which the ratio of the radius the connection fillet and the transverse dimension of the bottom is less than about 1/50.
• this container has, compared to an ordinary container, a seat (also called “laying plan”) wider and more rigid. This results in increased stability of the container in current use.
• FIG. 1 is a sectional elevational view illustrating a mold according to a known embodiment, shown in FIG. low position of the mold bottom;
• Figure 2 is a sectional elevation view illustrating the mold of Figure 1, shown with a container being blown, in an intermediate position of the mold bottom;
• Figure 3 is an elevational sectional view illustrating the mold of Figures 1 and 2, in the upper position (final) of the mold base;
• Figure 4 is a partial sectional view showing a container made by stretching blow in a mold as shown in Figures 1 to 3;
• FIG. 5 is a partial sectional view showing, on an enlarged scale, a detail of the container of FIG. 4, according to the inset
• Figure 6 is an elevational sectional view illustrating a mold according to the invention, shown in the lower position of the mold base, according to a first embodiment
• - Figure 7 is a sectional view showing, on an enlarged scale, a detail of the mold of Figure 6
• Figure 8 is a sectional elevation view illustrating the mold of Figure 6, shown with a container being blown, in an intermediate position of the mold bottom
• - Figure 9 is a sectional elevational view illustrating the mold of Figures 6 and 7, in the upper position (final) of the mold base
• Figure 10 is a partial sectional view showing a container made by stretch blow molding in a mold as shown in Figures 6 to 9
• Figure 1 1 is a partial sectional view showing, on an enlarged scale, a detail of the container of Figure 10, according to the inset Xl
• Figure 12 is an elevational sectional view illustrating a mold according to the invention, shown in the lower position of the mold base, according to a second embodiment
• Figure 13 is a sectional view showing, on an
• Figure 1 a mold 1 according to a known embodiment for the manufacture of containers by stretch blow molding plastic blanks.
• This mold 1 comprises a wall 2 defining an internal cavity 3 distributed around a main axis 4 of the mold, which when the containers to be formed are symmetrical with revolution forms an axis of symmetry of the mold 1.
• the wall 2 has, in a lower part, an opening 5 defining a passage for a bottom 6 of mold mounted movable with respect to the wall 2 between a low position, illustrated in FIGS. 1 and 2, in which the bottom 6 of the mold is spaced from the opening 5 downwards, and a high position, illustrated in FIG. 3, in which the bottom 6 of the mold seals the opening 5.
• the bottom 6 of the mold has an upper surface 7 which, in a raised position of the mold 1, close the cavity
• the blank 8 then the container 9 formed therefrom, rest on an upper face of the mold 1 via a flange 11, which delimits a neck 12 of the container 9, kept out of the mold 1.
• the container 9 Under the flange 11, the container 9 has a body 13, which extends generally in the axial direction, and a bottom 14, which extends generally in the radial direction from a lower end 15 of the body 13.
• the container 9 has a fillet 16 having an arcuate profile.
• the wall 2 has a lateral surface 17 which extends generally in the axial direction, and forms the impression of the body 13 of the container 9. As can be seen in FIGS. 1 to 3, the wall 2 has, around the opening 5, a protruding annular rim 18. This flange 18 has an annular upper surface 19 which extends radially substantially perpendicularly to the lateral surface 17. An arcuate profile fillet 20 connects the side surface 17 at a lower end thereof to the annular surface 19.
• the annular surface 19 terminates inwards (i.e. in the direction of the axis) by an edge 22 forming a sharp edge which delimits the opening 5 upwards on the cavity side.
• the mold 1 being in its configuration illustrated in Figure 1, with the bottom 6 of the mold in its lower position, it introduces the previously heated preform.
• the preform is stretched by means of an extension rod, all while blowing air at pre-blowing pressure (less than 15 bar).
• the blank 8 is then completely pressed against its imprint, formed by all of the following surfaces: the lateral surface 17 of the wall 2, which forms the body 13 of the container 9; the upper annular surface 19 of the flange 18 and the upper surface 7 of the bottom 6 of the mold, which together form the bottom 14 of the container 9; the fillet 20 between the lateral surface 17 of the wall 2 and the annular upper surface 19 of the flange 18, which forms the fillet 16 between the body 13 and the bottom 14 of the container 9.
• the bottom 14 of the container 8 has an annular outer surface 23, which abuts the fillet 16 and corresponds to the counterprint of the annular upper surface 19 of the rim 18 and extends towards inside, by a vault 24.
• the vault 24 is divided into three concentric regions, namely, from the center to the periphery: - a central pin 25, which projects inwardly from the container 8; a flexible annular membrane 26 (designed to flex under the effect of a hot filling, then to return to its initial position during the cooling of the liquid), which extends radially from the pin 25; an annular step 27, which extends substantially axially to the periphery of the annular membrane 26 and connects it to the annular outer surface 23.
• An annular portion 28 of the outer surface, located at the junction with the step 27, forms a seat of the container 9, by which it is in contact with any plane support on which it is laid flat.
• the bottom 14 has insufficient structural rigidity to allow any economy of material.
• the inventors have reflected on modifications of the structure of the mold 1 in particular to allow better drawing of the bottom 14 of the container 8 during its manufacture. Two exemplary embodiments proposing such structural modifications are described below, with reference respectively to FIGS.
• the mold 1 comprises a wall 2 defining an internal cavity 3 distributed around the main axis 4 of the mold 1.
• An opening 5 is provided in the lower part of the mold 1 to allow the passage of the mold bottom 6 mounted movable relative to the wall 2 between its lower position, illustrated in Figures 6 and 8, wherein the bottom 6 of the mold is spaced from the opening 5 downwards, and its upper position, illustrated in Figure 9, in which the bottom 6 of the mold seals the opening 5.
• the mold bottom 6 closes the cavity 3 and completes the impression against which the blank 8 is applied during blowing.
• the footprint of the bottom 14 of the container 9 is formed entirely on the bottom 6 of the mold, and more precisely by the upper surface 7 thereof.
• the wall 2 does not comprise, unlike the known embodiment, no annular rim in its lower part, the upper edge 22 of the opening 5 coinciding with the lower end 21 of the side surface 17 of the wall 2 forming the cavity of the body 13 of the container 9.
• the transverse dimension B (that is to say, in the case of a cavity 3 having a symmetry of revolution, the outer diameter) of the mold bottom 6 at its surface 7 upper being substantially equal to the transverse dimension A of the side surface 17 of the wall 2, measured at its lower end 21.
• This structural feature can be characterized on the wall 2 of the mold 1 itself, insofar as only one operating clearance distinguishes the transverse dimension B from the upper surface 7 of the mold bottom 6, measured at its outer edge 29. , the transverse dimension (which will also be noted B) of the wall 2, measured at the upper edge 22 of the opening 5.
• the transverse dimension B of the upper edge 22 of the opening 5 is equal to the transverse dimension A of the lateral surface 17, measured at its lower end.
• the side surface 17 of the wall is, in the vicinity of its lower end 21, substantially vertical, that is to say that it extends substantially axially.
• this characteristic can be translated by an angular prescription: the tangent to the lateral surface 17 of the wall, measured at the lower end thereof, forms with the axis 4 of the wall 2 a lower angle ⁇ or equal to 30 °, and preferably less than 10 °.
• a lateral surface 17 with a zero tangent angle ⁇ i.e., the lateral surface 17 is tubular near its lower end.
• this angle ⁇ is about 7 °.
• the upper surface 7 of the mold bottom 6 has, on its periphery, an annular portion which extends substantially in a radial plane.
• the tangent to the upper surface 7 of the mold bottom 6 at its outer edge 29 forms with the axis a right or substantially right angle ⁇ . Since, in the upper position of the mold base 6, the outer edge 29 of the mold base 6 is at the lower end of the lateral surface 17, it is understood that the junction between the lateral wall 2 and the surface 7 upper mold bottom 6 is in the form of a cutaway (ignoring the operating clearance between the bottom 6 of the mold and the opening 5).
• Figures 12-17
• This second embodiment is distinguished from the first by the presence, in the lower part of the wall 2, around the opening 5, of a projecting annular rim 18 of slight radial extension, which has an upper surface 19. extending in a transverse plane substantially perpendicular to the axis 4, and forming the impression of the seat 28 of the container 9.
• the ratio between the dimension B transverse of the upper edge 22 of the opening 5 and the transverse dimension A of the lower end 21 of the lateral surface 17 is greater than 0.95. In the illustrated example, this ratio is equal to about 0.98.
• the angular prescription of the first example, aimed at the tangent to the lateral surface at its lower end, remains valid.
• the lateral surface 17 is more open with, at its lower end 21, an angle ⁇ of tangent of 13 ° about. It should be noted that, with the clearance, the transverse dimension of the mold base 6, measured on the peripheral edge 29 of its upper surface 7, is equal to the transverse dimension of the upper edge 22 of the opening 5.
• This embodiment provides a container 9 substantially identical to that of the first example.
• the bottom 6 of the container can be stretched to a greater extent than in the known molds, since the absence (for example 1) or the minimization (for example 2) a sharp edge under the lower end 21 of the wall 2 causes the material to undergo no shear (in Example 1), or very little (in Example 2).
• the bottom 6 of the mold can therefore be kept in its lower position longer before its ascent is controlled, which increases the stretching of the material not only at the bottom 14, but also at the junction between the bottom 14 and the body 13.
• the additional stretching makes it possible to better distribute the material over the entire bottom 14, and to reduce the amount of amorphous material, in particular in the pin 25, to the benefit of the structural rigidity of the bottom 14 at the level of the seat .
• the radius of the fillet 16 between the body 13 and the bottom 14 is relatively large compared to the transverse half-size (that is to say the radius) of the 14, in a ratio greater than about 1/10 (for example, for a PET container with a capacity of 0.5 I, the bottom 6 has a radius of 30 mm, the radius of the leave 16 is generally greater at 5 mm).
• This dimensional characteristic results from the manufacturing constraints, the deformation that the material can undergo, given its viscosity (related to the heating temperature), its thickness (related to the drawing ratio) and the blowing pressure that does not allow to reduce the radius of the leave 16, except to see appear in it breaker primers due to local overloads.
• the greater stretching of the material, and the subsequent decrease in its thickness make it possible to increase its deformability and to make a fillet 16 with the radius is small in front of the half-size (that is, the radius) of the bottom 14, in a ratio of less than about 1/50.
• the fillet radius 16 may be less than 1 mm for example of the order of 0.5 mm.
• junction, in the mold 1, between the lateral surface 17 on the one hand and the upper surface 7 of the bottom 6 (in example 1) or the upper surface 19 of the annular flange 18 (in example 2), under form of a cutaway, allows for such a holiday.
• the bottom 14 of the container 9 has a seat 28 offset at most towards the periphery of the bottom 14, with a fillet 16 connecting with the body 13 of small radius, as explained above.
• the junction between the bottom 14 and the body 13 of the container therefore appears more "square" than in the known embodiments, to the benefit of the stability of the container 9.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Ceramic Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Containers Having Bodies Formed In One Piece (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

Family

ID=40786481

Family Applications (1)

Country Status (6)

Cited By (22)

Families Citing this family (14)

Citations (13)

Family Cites Families (7)

• 2008
  • 2008-11-19 FR FR0806473A patent/FR2938464B1/fr not_active Expired - Fee Related
• 2009
  • 2009-11-17 MX MX2011005247A patent/MX2011005247A/es active IP Right Grant
  • 2009-11-17 US US13/129,990 patent/US8881937B2/en not_active Expired - Fee Related
  • 2009-11-17 WO PCT/FR2009/001316 patent/WO2010058098A2/fr active Application Filing
  • 2009-11-17 CN CN200980153881.8A patent/CN102271895B/zh not_active Expired - Fee Related
  • 2009-11-17 EP EP09760943.2A patent/EP2349678B1/fr not_active Not-in-force

Patent Citations (13)

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