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
  • B65D1/0284—Bottom construction having a discontinuous contact surface, e.g. discrete feet
• • 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
  • 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

Definitions

• the present invention relates generally to the field of manufacturing, by blow molding or stretch-blow molding, containers, in particular bottles, made of a thermoplastic material such as PET.
• the invention relates to improvements made in the design of a mold base for a mold for manufacturing, by blow-molding or stretch-blow molding, containers, in particular bottles, made of a thermoplastic material such as PET, said containers having a body and having a bottom of the so-called petaloid type with a plurality of feet which are equidistantly distributed angularly, which extend approximately parallel to the axis of the container and which are separated from each other by radiating valleys at full depth curvilinear convex, said mold bottom having a mold cavity having, for molding the aforesaid bottom of the containers, a plurality of cavities which are angularly distributed equidistantly, which extend approximately parallel to the axis of the mold base and which are separated from each other by radiating crestal ridges extending in an arc from re of the molding cavity, the bottoms of said cavities being distributed over a substantially circular contour having a given base diameter.
• dorsal is meant a projecting portion, elongate substantially radially, of the mold base which leads, in the bottom of the molded container, to the formation of a susdite "valley".
• the part of the containers that is the most delicate to manufacture is the bottom. It is indeed the container bottom which supports the weight of the column of liquid contained in the container and, in the case where it has insufficient mechanical strength, it loses its shape and the container can no longer rest stably on a support .
• the bottom precisely so that it can have the desired strength, has a sensitive wall thickness, proportionally greater than that of the rest of the container. As a result, it requires, relatively speaking, more material than the container body whose wall currently reaches a very small thickness that becomes difficult to reduce.
• the bottom therefore constitutes the part of the container whose correct forming by the blowing or stretch-blow molding operation is the most difficult to achieve, because the substantially larger thickness of material leads to slower drawing and to a less easy form.
• the bottom usually has a complex shape, or very complex, with many reliefs hollow and projecting whose correct conformation leads to the desired strength.
• the very important angular course that the material must undergo during the deformation that leads from the hemispherical shape of the bottom of the initial preform to the wall with reversed orientation supporting on an approximately conical surface ⁇ defining the foot in the direction of the center of the finished container, depending on the locations, the material may be angularly traversed up to 90 ° or more, allied to the substantial thickness of the material in this area, can lead to insufficient plating of the material on the wall of the molding cavity and poor cooling of the material against the mold, which may result in a lower quality of the bottom or parts of the bottom of the container
• this important angular course of the material requires a certain time.
• the object of the invention is to propose an improved solution which makes it possible to manufacture petaloid-bottomed containers under improved conditions which eliminate the abovementioned drawbacks while being compatible with an increase in production rates sought by the manufacturers.
• the invention provides a mold base for a mold for manufacturing, by blow-molding or stretch-blow molding, containers, in particular bottles, made of thermoplastic material such as PET, such as mentioned in the preamble, which mold bottom is characterized, being arranged according to the invention, in that the mold base has intermediate zones which are each defined between two consecutive dorsals and the cavity situated between these two ridges and which are substantially planes in a plane substantially perpendicular to the axis of the mold bottom.
• the mold bottom structure that has just been described is remarkably simple from the point of view of its geometry compared to the very complex forms of petaloid bottoms so far manufactured.
• the stretching of the material is less than in the backgrounds and that in the central part of the Mold cavity having the planar portions of the spacer areas, the material is better pressed against the mold wall and thus better cooled.
• the angular path of at least some parts of the material of the bottom of the preform, during its course during molding, is considerably reduced compared to the previous process and therefore requires less time: this is favorable in the frame of the search for a higher manufacturing rate.
• the cavities have, in diametral section of the mold base, a substantially circular arc shape.
• the cavities of the mold bottom used for molding the feet of the receptacles are substantially elongated in a circumferential direction.
• the feet of the containers are in the form of spherical caps elongated circumferentially; these loose shapes with relatively large radii of curvature of the mold bottom make the feet of the containers more easily moldable than the narrow feet with small radii of curvature of the traditional petaloid bottoms.
• each cavity is connected with the substantially flat portion of the respective intermediate area by an arcuate fillet having substantially the same radius as the radius of the cavity considered in diametral section of the mold base.
• all the curved surfaces have large radii of curvature, which again favors a correct and rapid molding of the material.
• the radial extent of a cavity is approximately half of the radial extent of said intermediate area, so that the amount of material that is to be stretched to a maximum , which is necessary for the formation of each foot at the same time as it emerges flat portions of notable surface in the central part of the mold bottom.
• each substantially flat intermediate region is substantially proportional to the diameter of the manufactured container; in particular, the ratio of the diameter of the circular distribution contour of the bottoms of the cavities of the mold base (which corresponds to the seat diameter of the manufactured container) to this radial dimension of each substantially flat intermediate zone is between approximately 3 and 2.5. preferably between about 2.8 and 2.7.
• the material of the thick bottom of the preforms undergoes only a minimal stretching and is simply unwound on the flat portions of the intermediate areas of the molding cavity, so that the initial material thickness of the bottom of the preforms is found little stretched in the corresponding planar portions of the bottom of the containers.
• a mold base arranged in accordance with the invention makes it possible to manufacture containers having simplified shaped bottoms over a wide dimensional range and under improved conditions in terms of improving the conditions for forming the bottoms of the containers and increasing the rates. especially for the manufacture of containers of large capacity (for example from 1.5 to 3 liters), all characteristics that perfectly meet the expectations of the practice.
• I th invention also provides a molding device for manufacturing, by blow molding or stretch-blow molding, containers, in particular bottles, made of thermoplastic such as PET, said containers having a body and having a petaloid-type bottom with several feet which are distributed equidistantly angularly, which extend approximately parallel to the axis of the container and which are separated from each other by radiating valleys convex bottom, which molding device comprises at at least one mold consisting of at least three parts including a mold bottom having a mold cavity comprising, for molding the aforesaid bottom of the containers, a plurality of cavities which are angularly distributed equidistantly, which extend approximately parallel to the axis from the bottom of the mold and which are separated from each other by radiating ridge ridges s' arcuate from the center of the mold cavity, the bottoms of said cavities being distributed over a substantially circular contour, which molding device, being arranged in accordance with the invention, is characterized in that the mold base is arranged
• - Figure 1 is a top view of a mold base arranged according to the invention
• - Figure 2 is a diametrical sectional view along line II-II of the mold base of Figure 1;
• Figure 3 is a three-quarter perspective view from above of the mold bottom of Figure 1;
• Figure 4 is an isometric perspective view of three quarters from below the bottom of a molded container with a mold bottom arranged according to Figures 1 to 3.
• FIG. 1 there is shown a bottom 1 of mold for fitting a mold for manufacturing, by blow molding or stretch blow molding containers, especially bottles, thermoplastic material such as PET.
• the containers 2 to be manufactured with this mold have a body 3 and have a bottom 4 of the so-called petaloid type having a plurality of protrusions forming feet 5, generally in number between three and seven, in practice. between four and six (five in the example shown), which are angularly distributed equidistantly, which extend approximately parallel to the axis 6 of the container and which are separated from each other by valleys 7 radiating bottom 8 convex curvilinear extent. All the valleys 7 converge at the center of the bottom which is constituted in the form of a protrusion in the form of a circular, central plateau projecting outwards.
• the bottom 4 of the container is connected to the body 3 of the container by a zone 9 of substantially cylindrical connection of revolution.
• the bottom 1 of the mold is provided with a mold cavity C which comprises, for the molding of the aforesaid bottom 4 of the containers 2, a plurality of cavities 11 in number equal to the number of feet 5 of the bottom 4, generally between three and seven, in practice between four and six (five in the example illustrated in FIGS. 1 to 3), which are equidistantly distributed angularly (mutual angular spacing of 72 ° in this example), which extend approximately parallel to each other.
• axis 12 of the mold bottom 1 which is also the axis of the molding cavity C
• radiating ridges 13 that is to say protruding parts, elongated substantially radially of the molding cavity C which leads, in the bottom 4 of the molded container, to the formation of the aforesaid valleys 7).
• Each dorsal 13 has a ridge 14, of concave extension, in the form of a circular arc centered on the axis 12 of the mold base and originating on this axis 12.
• the bottoms 15 of the cavities 11 are distributed over a substantially circular contour 16 having a given base diameter D, this diameter corresponding to the diameter of the base of the bottom 4 of the containers (diameter of the circular contour on which the zones of the feet 5 are distributed. by which the containers rest on a plane support).
• the center of the molding cavity C has a shallow circular recess 17 whose dimensions are adapted to receive the projecting portion of the funds of the initial preforms, corresponding to their injection point, which facilitates the formation of the tray. 10 supra of the container bottom 4 by allowing proper centering of the preforms.
• the intermediate zones 18 which are each defined between two consecutive ridges 13 and the corresponding cavity 11 situated between these two dorsals and which are substantially flat in a plane P substantially perpendicular to the axis 12 of the mold base 1 and therefore tangent to said ridges 14 in the center of the mold bottom.
• each cavity 11 advantageously has a radial cross section substantially in the form of an arc of radius of radius r_, while it is enlarged in a circumferential direction in such a way that that on the bottom of the respective foot 5 of the container is defined a seat having a width sufficient to provide the container a stable support on a flat support.
• the height h of the cavities 11 is substantially smaller than their radius
• each cavity 11 thus shaped has approximately a spherical cap shape stretched circumferentially as shown in Figures 1 and 3.
• each cavity 11 is connected with the respective substantially flat intermediate region 18 by a fillet 19 in an arc having substantially the same radius r as the radius of the cavity considered in diametral section of the mold base, as visible in Figure 2. This avoids the connections of small radius, which facilitates a better veneer of the material against the wall of molding.
• the radial extent of a cavity 11 in a respective intermediate zone 18 is approximately half of the radial extent of said intermediate zone 18.
• the radial dimension R of each substantially flat spacer zone 18 is proportional to the diameter of the containers manufactured; in particular, if one refers to the diameter D of the circular contour on which are distributed the bottoms 15 of the cavities 11 of the mold bottom 1 as explained above (and which corresponds to the seat diameter or diameter of the distribution contour of the feet 5 of the finished container), the ratio D / R of this diameter D to said radial dimension R of the substantially planar intermediate regions 18 is between about 3 and 2.5, preferably between about 2.8 and 2.7.
• the bottom of the preform is substantially flattened perpendicularly to the axis 12 of the mold bottom 1 without being substantially radially stretched.
• the material undergoes a displacement amplitude that is less than when molding conventional petaloxid bottoms in which the corresponding areas rely on a frustoconical contour open downwards and is thus better pressed against the molding wall, which leads to its best cooling.
• the valleys 7 which extend up to the center of the bottom 4 of the The container (up to the central projecting plate 10) defines between them, behind the feet 5 towards the center of said bottom 4, portions 20 of approximately triangular shape and substantially planar, within an outline (in phantom on Figure 4) substantially circular whose radius has the value R above.
• the arrangements according to the invention find a particularly preferred application in a molding device for manufacturing, by blowing or stretch-blow molding, containers 2, especially bottles, thermoplastic material such as PET, said containers 2 having a body 3 and having a bottom 4 of the so-called petaloid type with several feet 5 which are distributed angularly equidistantly, which extend approximately parallel to the axis 6 of the container and which are separated from each other by valleys 7 radiating bottom 8 convex curvilinear extent, which molding device comprises at least one mold consisting of at least three parts of which a mold base 1 comprising, for the molding of the aforesaid bottom 4 of the containers, a plurality of cavities 11 which are angularly distributed equidistantly, which extend approximately parallel to the axis 12 of the bottom 1 of the mold and which are separated from each other; others by radially extending ridge-like ridges 14 extending in an arc from the center of the molding cavity, the bottoms 15 of said cavities 11 being distributed over a substantially circular

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Ceramic Engineering (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=36685510

Family Applications (1)

Country Status (7)

Families Citing this family (5)

Family Cites Families (8)

• 2006
  • 2006-02-20 FR FR0601482A patent/FR2897554B1/fr not_active Expired - Fee Related
• 2007
  • 2007-02-13 CN CN2007800060710A patent/CN101389537B/zh not_active Expired - Fee Related
  • 2007-02-13 JP JP2008555827A patent/JP2009527383A/ja not_active Ceased
  • 2007-02-13 US US12/279,911 patent/US20090087507A1/en not_active Abandoned
  • 2007-02-13 CA CA2642809A patent/CA2642809C/fr not_active Expired - Fee Related
  • 2007-02-13 EP EP07730965A patent/EP1996473A2/de not_active Withdrawn
  • 2007-02-13 WO PCT/FR2007/000252 patent/WO2007096499A2/fr active Application Filing

Non-Patent Citations (1)

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