WO1990002645A1 - Emballage ameliore - Google Patents

Emballage ameliore Download PDF

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Publication number
WO1990002645A1
WO1990002645A1 PCT/AU1989/000394 AU8900394W WO9002645A1 WO 1990002645 A1 WO1990002645 A1 WO 1990002645A1 AU 8900394 W AU8900394 W AU 8900394W WO 9002645 A1 WO9002645 A1 WO 9002645A1
Authority
WO
WIPO (PCT)
Prior art keywords
plastics material
die member
base
roll
forming
Prior art date
Application number
PCT/AU1989/000394
Other languages
English (en)
Inventor
Anthony James Murray Garwood
Original Assignee
Garwood Limited
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 Garwood Limited filed Critical Garwood Limited
Publication of WO1990002645A1 publication Critical patent/WO1990002645A1/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
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/26—Component parts, details or accessories; Auxiliary operations
    • B29C51/30—Moulds
    • B29C51/306—Moulds with means for forming a rim
    • 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
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/04—Combined thermoforming and prestretching, e.g. biaxial stretching
    • 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
    • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • B29C51/10—Forming by pressure difference, e.g. vacuum

Definitions

  • This invention relates to producing packaging bases and to producing roll lips on plastics articles and relates particularly but not exclusively to producing roll lips on plastics material bases for use in packaging foodstuffs.
  • plastics material bases are formed by either male or female die members by passing a sheet of the plastics material between heat banks or in proximity to heat banks so that the material is heated to a thermo-forming temperature and then causing the heated material to be brought into contact with a male or female die member by drawing or blowing the material onto a male or female die member to form the base.
  • a significant problem which occurs with this type of method is that the base is thinner in some parts than in other parts.
  • the peripheral edges of the base remain generally of the same thickness as the sheet material but the portion of the base which is forced into the die member is of reduced thickness due to the material being stretched to conform to the shape of the die member.
  • the bottom part of the base member has generally the same thickness as the material sheet but the side walls and peripheral edge have a reduced thickness in view of the fact that the material is stretched over the corresponding parts of the die.
  • the plastics material bases which have been formed are usually stacked one on top of the other in nested relationship. Because the bases have an upper peripheral flange it makes separation of the nested bases extremely difficult as the flanges lie on top of each other in direct contact with each other. It is not possible to easily separate the flanges and hence the bases.
  • the bases are usually formed by a thermo-forming process from a continuous sheet of plastics P.V.C. material. The bases are then separated from the plastics material sheet as by punching or otherwise cutting around the outer edge of the peripheral flange or lip on the bases. The cutting produces a sharp and/or jagged edge which, in turn, can cause cutting of persons' fingers. The sharp or jagged edge makes separation of nested bases by mechanical means extremely difficult.
  • a roll lip be provided on the bases whereby it will space the upper flanges of the bases in spaced apart relation when the bases are nested together.
  • a roll lip of a certain configuration it is possible to have any edge of the base displaced inwardly relative to the outermost surface of the roll lip. Thus any sharp edges which may be produced will be less likely to cause a problem than in the prior art.
  • An object of a first aspect of this invention is to provide a method for forming a base which overcomes these problems.
  • the invention in a first aspect, may be said to reside in a method of forming a packaging base member using both a female die member and a male die member comprising the steps of; bringing a plastics material to a thermo-for ing temperature, causing the heated plastics material to conform to the shape of one of a male or female die member for partly forming the base member, causing the partly formed base member to conform to the shape of the other of the male or female die member to finally form the base member; wherein a forming surface of the male or female die member which forms the partially formed base is of lesser depth than the forming surface of the other of the male or female die member which forms the base member.
  • the invention in its first aspect may also be said to reside in apparatus for forming a packaging base, said apparatus comprising heating means for heating a plastics material to a thermo-forming temperature, a first die member of male or female configuration having a forming surface for forming said material into a partially formed base, a second die member of the other • of the female or male configuration having a forming surface for forming the partially formed base into the packaging base member, the said forming surface of the male or female die which forms the partially formed base being of lesser depth than the forming surface of the male or female die member which forms the base from the partially formed base.
  • the plastics material is of reduced thickness on side walls and peripheral edge of the base but of the same thickness as the plastic sheet on the bottom of the base and since the base is then finally formed by the, for example, female die member, the bottom part of the base is reduced in thickness in this forming step whilst generally maintaining the same thickness of the side wall and peripheral edge portion to thereby result in a base which has a substantially constant thickness throughout. This therefore more evenly spreads the material over the entire base and therefore results in a base which does not have generally thick portions and very thin portions but rather a base which is of intermediate uniform thickness.
  • the intermediate uniform thickness overcomes problems which may occur with bases with have very thin portions and therefore provides a packaging base of better quality and of more robust nature.
  • the present invention also* proposes a method of producing plastics material members with roll lips.
  • the invention also envisages apparatus for producing a plastics material member with a roll lip. Therefore in accordance with a further broad aspect of the present invention there may be provided a method of forming a plastics material member with a roll peripheral lip comprising:
  • the roll is produced in a movable die member which has severing means formed thereon.
  • the movable die member will have a cavity which defines a part at least of the roll lip, and it will have a severing means as well.
  • the plastics material can be formed into the roll in the 'cavity whereupon the movable die can then be moved to permit the severing to occur.
  • the clamping is effected between a heating member and the movable die member.
  • a plastics material member produced by the method outlined above is also within the scope of the present invention.
  • Apparatus for performing the method and for producing a plastics material member of this type is also included within the scope of the invention.
  • Figure 1 is a vertical cross-sectional view taken through a preferred plastics material base of the present invention and proposed to be used in the packaging industry;
  • Figure 2 is a vertical cross-sectional view taken through preferred apparatus of the present invention used for producing a base and a roll lip of a type shown on the edge of the packaging base shown in Figure 1;
  • Figure 2A is a detailed view of the circled part of Figure 2;
  • Figure 3 is a view showing a second embodiment of the roll lip forming method and apparatus; and Figure 4 is a view showing a third embodiment of the roll lip forming method.
  • FIG. 1 there is shown a plastics material base as of P.V.C. of approximately 400 micron thickness. Typically the plastics material is transparent so that goods such as fresh meats, vegetables and the like which are eventually placed within the base 1 can be viewed easily by an intended purchaser.
  • the base 1 is of rectangular configuration with a bottom 3, side walls 5 and an upper peripheral lip or flange 7.
  • a roll peripheral lip 9 is produced in a peripheral zone of the peripheral lip or flange 7.
  • Prior art bases 1 did not include a roll peripheral lip 9 but terminated at the outer edge of the peripheral lip or flange 7.
  • the arrangement of the roll peripheral lip 9 is such that when the bases 1 are nested together, the peripheral lip or flanges 7 will be spaced apart by a distance generally equal to the external diameter of the roll peripheral lip 9.
  • the roll peripheral lip 9 may be upwardly extending rather than downwardly extending as shown in Figure 1.
  • one or more heat banks 11 are provided for heating the plastics material P from which the bases 1 are made.
  • the heat banks 11 heat the plastics material to a thermo-forming temperature and the bases 1 are formed by a pair of dies Dl and D2.
  • the dies Dl and D2 are provided with die members A, B and C which are more fully shown in Figure 2A.
  • the die member Dl is a male die member and the plastic sheet P is caused to conform to the forming surface of the die Dl to form a partially formed base which has a bottom 3, side walls 5 and a lip or flange 7.
  • the plastic sheet P can be brought into contact with the die Dl by moving the die Dl relative to the die D2 and by applying air suction through air passages 15 in the die Dl to cause the plastic sheet P to conform to the shape of the die Dl.
  • the plastic sheet P conforms to the shape of the die Dl the plastic sheet is stretched in the vicinity of the walls 5 and flange 7 and this reduces the thickness of the plastic sheet at those areas of the partially formed base.
  • the partially formed base 1 is caused to conform to the forming surface shape of the die D2 by reversing the air flow through the passages 15 so that the partially formed base 15 is blown into the die D2 and/or by suction applied to the passages 15 in the die D2.
  • the base Since both a male and a female forming process takes place to form the base 1, the base has a generally uniform thickness of intermediate thickness between the generally thick parts of a base and thin parts of a base which are otherwise formed by conventional base forming methods. Therefore, the plastics material which forms the base 1 is generally uniformly spread throughout the base 1 and a more robust base is provided.
  • the depth X of the forming surface of the die Dl is less than the depth Y of the forming surface of the die D2.
  • the die which forms the partially formed base is thinner than the die which forms the fully formed base, i.e.
  • the dies Dl and D2 could be reversed and the female die D2 could be used to form the partially formed base and be of smaller forming surface depth than the die Dl which fully forms the base.
  • Figure 2A shows a detailed view of the circled part of Figure 2 which forms the peripheral lip 9.
  • the die part B can be integral with the die D2 or could be arranged for location beside the die D2 and for movement relative to the die D2. It will be noted that the dies B and C define a concave cavity 17 and that the die C has a severing means 19.
  • the die member A is in the form of a plug which is movable relative to the die member Dl and the die members B and C.
  • the plastics material P is clamped in a pair of clamping members 14 which are provided downstream of a heat bolster 16.
  • the die member A is moved downwardly relative to the die Dl and suction is applied to air passages 18 which causes the plastics material P to generally conform to the shape of the die member A.
  • the die members C and/or B are then moved upwardly relative to the die member A so that the severing means 19 holds the plastics material P against the heat bolster 16. Air may then be blown through the air passages 18 to cause the plastics material P to move outwardly of the die A and to conform to the concave shape 17 defined by the die members B and C.
  • the die member C may then be moved upwardly so that the severing means 19 severs the plastics material P at the edge of the formed peripheral lip 9.
  • the peripheral lip 9 may be formed by movement of the die members A, B and C generally at the same time as the base 1 is formed by the die members Dl and D2 or may be formed subsequently to the formation of the base 1.
  • the die members A, B and C may also be reversed depending on whether the lip 9 is to be formed in the upward direction or downward direction.
  • the die members B and C are preferably cooler, in the vicinity of cavity 17, than the die member A to enable the plastics material to solidify when it contacts the die member B and C to thereby maintain the shape of the peripheral lip 9.
  • the forming of the roll lip 9 can be considered to employ the teachings of the inventive concept relating the forming of the base 1 whereby a generally uniform thickness will be provided to the plastics material in the roll lip 9.
  • FIG. 3 there is shown- a close up vertical cross-sectional view at one side of a second embodiment of the apparatus used for producing the roll peripheral lip 9 in the base 1.
  • the apparatus has a heat bank 11 which is used for heating the P.V.C material or other suitable plastics material from which the bases 1 are made, to a thermo-forming temperature.
  • the apparatus has three movable die members shown respectively as A, B and C in Figure 3. During the forming procedure of the roll peripheral lip 9 the movable die member A is first elevated so that the plastics material is clamped at the upper surface 13 of movable die member A and the undersurface of the heat bank 11.
  • Movable die member B is then elevated to a point where the plastics material is held but not necessarily clamped adjacent to the undersurface of the heat bank 11. Air and/or gas is then allowed to pass through passageway means 15 in the heat bank 11 to cause the plastics material in a peripheral zone of the peripheral lip or flange 7 to move downwardly into the concave cavity 17 in the movable die member A. Movable die member C can then be elevated so that an upper surface - severing means 19 - engages with the undersurface of the plastics material and slightly compresses it relative to the heat bank 11. Air and/or gas is continued to be passed through the passageway means 15. An increasing air and/or gas pressure may be required at this time.
  • the zone of the peripheral lip or flange 7 is then caused to conform to the shape of a concave cavity 21 of the movable die member C.
  • passageway means 23 may be provided in the movable die member C and through which air and/or gas can be exhausted. The exhausting of gas in this manner will in effect provide a low pressure gas region between the surface of the plastics material and the surface of the concave cavity thus assisting the forming of the plastics material into the roll peripheral lip 9.
  • the movable die member C can then be raised further whereby to sever said roll to form a free edge 25 in the plastics material at a side of the roll peripheral lip 9 opposite to where said roll peripheral lip 9 extends from the plastics material of the peripheral lip or flange 7.
  • the movable die member B may be elevated to slightly compress the material in the peripheral lip or flange 7 causing it to displace slightly sideways and to perhaps close the upper most • portion 27 of the roll peripheral lip 9.
  • the plastics material will be at a thermo-forming temperature by virtue of its contact with the heat bank 11 and thus there may be partial melting of the plastics material to effect bonding when the uppermost portion 27 closes.
  • Figure 3 will provide for a roll peripheral lip 9 to be produced on a plastics material member.
  • Movable die member C can be displaced downwardly relative to die member B and because of the flexible nature of the roll peripheral lip 9 will easily pass by slight flexible radially inward displacement thereof. Similarly, movable die member B can be lowered causing the roll peripheral lip 9 to then flexibly displace radially outwardly.
  • Figure 4 shows a variation of the apparatus shown in Figures 2 and 3 where the movable die member C now has a cavity to completely shape the roll peripheral lip 9.
  • the arrangement does not require the use of a movable die member A as the initial clamping is affected by the free edge 25 of the movable die member C on the undersurface of the heat bank 11.
  • the movable die members A, B and C can be suitably temperature controlled to be at temperatures lower than that of the heat bank.
  • the roll peripheral lip 9 is such that, if required, a snap lid (not shown) * can be caused to snap engage with the roll peripheral lip 9 to close or contain any goods in the base 1.
  • the roll peripheral lip 9, because of its hollow and flexible nature is such that a good seal can be made with the lid.

Landscapes

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

Abstract

Le procédé et l'appareil décrits servent à produire des éléments de base (1). Le procédé consiste à déplacer un matériau plastique entre un moule mâle et un moule femelle (D1 et D2) après avoir amené le matériau plastique à une température de thermoformage. Le matériau est ensuite amené à prendre la forme du moule (D1) par l'application d'une pression depuis une source d'aspiration de gaz à travers les passages (15). Le matériau est ensuite amené à prendre la forme du moule (D2) par application de pression par aspiration de gaz à travers les passages (15). Le façonnage initial de la base (1) est effectué par le moule (D1) et le façonnage final est effectué par le moule (D2). La profondeur du moule (D1) est inférieure à celle du moule (D2). Le procédé et l'appareil décrits permettent de conférer aux bases (1) une épaisseur sensiblement uniforme par rapport à une base (1) dont la forme et la grandeur finales sont obtenues par formage sur un seul moule. Le procédé et l'appareil décrits permettent également de produire un bec périphérique cylindrique (9) sur les bases (1). Ainsi, lorsque les bases sont empilées par engagement les unes dans les autres, les rebords (7) sont séparés par le diamètre du bec périphérique cylindrique (9) et les bases sont par conséquent faciles à désassembler de leur position d'engagement.
PCT/AU1989/000394 1988-09-16 1989-09-13 Emballage ameliore WO1990002645A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPJ0477 1988-09-16
AUPJ047788 1988-09-16

Publications (1)

Publication Number Publication Date
WO1990002645A1 true WO1990002645A1 (fr) 1990-03-22

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PCT/AU1989/000394 WO1990002645A1 (fr) 1988-09-16 1989-09-13 Emballage ameliore

Country Status (1)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995028272A1 (fr) * 1994-04-18 1995-10-26 Franco Cesano Appareil de production d'un article en matiere thermoplastique a section en contre-depouille
WO1995028271A1 (fr) * 1994-04-18 1995-10-26 Franco Cesano Appareil de production d'un element obtenu a partir de deux feuilles thermoplastiques
US5846578A (en) * 1994-04-18 1998-12-08 Cesano; Franco Apparatus for producing a component obtained from two thermoplastic sheets

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU4670064A (en) * 1964-07-08 1966-01-13 Illinois Toolworks Inc Process and apparatus for forming plastic cups orthe like
US3600753A (en) * 1969-09-29 1971-08-24 Koehring Co Differential pressure forming mold assembly for forming plastic articles in a thermoplastic web
US3737498A (en) * 1968-10-29 1973-06-05 Bird & Son Method for heat and vacuum-pressure machine molding
AU3642971A (en) * 1970-12-04 1973-06-07 Shell Internationale Research Maatschappij B.V. Method of making cupped articles from polyolefin plastic sheet
AU5346973A (en) * 1972-03-21 1974-09-19 Shell Internationale Research Maatschappij B.V. Apparatus and method fob moulding hollow articles from thermoplastics sheet
US3928523A (en) * 1973-12-26 1975-12-23 Peter Ward Moulding of synthetic plastics sheet material
JPS57131528A (en) * 1981-01-09 1982-08-14 Denki Kagaku Kogyo Kk Forming method of thermoplastic resin foamed sheet
JPS591211A (ja) * 1982-06-29 1984-01-06 Mitsubishi Plastics Ind Ltd 合成樹脂製びん形容器の成形方法
JPS5989114A (ja) * 1982-11-15 1984-05-23 Puramatsuku Kk 積層成形品の真空圧空成形方法

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU4670064A (en) * 1964-07-08 1966-01-13 Illinois Toolworks Inc Process and apparatus for forming plastic cups orthe like
US3737498A (en) * 1968-10-29 1973-06-05 Bird & Son Method for heat and vacuum-pressure machine molding
US3600753A (en) * 1969-09-29 1971-08-24 Koehring Co Differential pressure forming mold assembly for forming plastic articles in a thermoplastic web
AU3642971A (en) * 1970-12-04 1973-06-07 Shell Internationale Research Maatschappij B.V. Method of making cupped articles from polyolefin plastic sheet
AU5346973A (en) * 1972-03-21 1974-09-19 Shell Internationale Research Maatschappij B.V. Apparatus and method fob moulding hollow articles from thermoplastics sheet
US3928523A (en) * 1973-12-26 1975-12-23 Peter Ward Moulding of synthetic plastics sheet material
JPS57131528A (en) * 1981-01-09 1982-08-14 Denki Kagaku Kogyo Kk Forming method of thermoplastic resin foamed sheet
JPS591211A (ja) * 1982-06-29 1984-01-06 Mitsubishi Plastics Ind Ltd 合成樹脂製びん形容器の成形方法
JPS5989114A (ja) * 1982-11-15 1984-05-23 Puramatsuku Kk 積層成形品の真空圧空成形方法

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, M-171, page 166; & JP,A,57 131 528 (DENKI KAGAKU KOGYO K.K), 14 August 1982. *
PATENT ABSTRACTS OF JAPAN, M-290, page 100; & JP,A,59 001 211 (MITSUBISHI JUSHI K.K), 6 January 1984. *
PATENT ABSTRACTS OF JAPAN, M-325, page 16; & JP,A,59 089 114 (PURAMATSUKU K.K), 23 May 1984. *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995028272A1 (fr) * 1994-04-18 1995-10-26 Franco Cesano Appareil de production d'un article en matiere thermoplastique a section en contre-depouille
WO1995028271A1 (fr) * 1994-04-18 1995-10-26 Franco Cesano Appareil de production d'un element obtenu a partir de deux feuilles thermoplastiques
US5641379A (en) * 1994-04-18 1997-06-24 Cesano; Franco Apparatus for producing a thermoplastic article having an undercut cross-section
US5846578A (en) * 1994-04-18 1998-12-08 Cesano; Franco Apparatus for producing a component obtained from two thermoplastic sheets

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