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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/16—Making multilayered or multicoloured articles
  • B29C45/1635—Making multilayered or multicoloured articles using displaceable mould parts, e.g. retractable partition between adjacent mould cavities
  • B29C45/1639—Removable partitions between adjacent mould cavity portions
• • 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
  • B65D47/00—Closures with filling and discharging, or with discharging, devices
  • B65D47/04—Closures with discharging devices other than pumps
  • B65D47/06—Closures with discharging devices other than pumps with pouring spouts or tubes; with discharge nozzles or passages
  • B65D47/08—Closures with discharging devices other than pumps with pouring spouts or tubes; with discharge nozzles or passages having articulated or hinged closures
• • 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
  • B29L2031/56—Stoppers or lids for bottles, jars, or the like, e.g. closures
  • B29L2031/565—Stoppers or lids for bottles, jars, or the like, e.g. closures for containers

Definitions

• the invention relates to a method for molding capsules intended to be fixed to containers such as flexible tubes, vials or tube vials. Said capsules are provided with a pivoting cap closing a dispensing orifice.
• containers are intended for storing and distributing fluid, creamy or pasty materials, generally belonging to the cosmetic, food, household, pharmaceutical or parapharmaceutical fields. Subsequently we will group this type of container under the general term "tubes".
• the capsules fitted with a swivel cap offer the consumer the possibility of handling the tube with one hand and the assurance of not losing the stopper which, once detached to release the dispensing orifice, can be removed and unintentionally abandoned anywhere.
• Such capsules have found considerable development when it has been possible to mold them in one piece, which had the consequence of significantly reducing their manufacturing cost.
• the capsules thus produced include a base and a pivoting cap attached to this base.
• the base includes an upper plate provided with a dispensing orifice, an external skirt which is generally in the extension of the flexible skirt of the tube when the capsule is fixed on the tube and fixing elements intended to cooperate with means correspondents arranged on the head of the flexible tube.
• the cap is attached to the base, generally on the upper plate of said base, and often at the periphery, by means of a hinge. This generally comprises at least one film hinge, stressed in bending, and at least one, tensioning element, stressed in tension. The tensioning element, put in tension during the pivoting of the cap, facilitates the pivoting of the latter, the user only having to give a first impulse to trigger the opening or closing.
• the cap molded simultaneously with the rest is necessarily 0 made of the same material, which limits on the one hand the decorative possibilities of the capsule, giving it a monotonous, banal, even appearance. unsightly and on the other hand limits the comfort of use of the tube due to the rigid nature of the cap, which provides a cold contact to the touch, unpleasant, likely to injure the thumb of the user if the projection of gripping of the 5th cap has too pronounced relief.
• the Applicant has therefore sought to improve the appearance and the comfort of use of the capsule by giving the cap a color and / or a material different from that of the base. She turned to the technique of 0 bi-injection recently developed in the mold makers of capsules.
• the Patent applications FR 2 662 144 and EP 0826 606 are representative of the service capsules which it is now possible to obtain by means of such a process.
• the cover, the external part of the base and the hinge elements are made of the same rigid material, of the polypropylene type.
• the applicant sought to obtain a service capsule having a base made of a first plastic material and a cap made of a second plastic material, the border between the plastics materials having to pass at the level of the hinge separating the base of the cap, without this having consequences on the mechanical strength of said hinge during use of the tube.
• the subject of the invention is a sequential multi-material injection molding process for manufacturing a part comprising at least two parts of complementary shapes made of a different plastic material, movable relative to one another by pivoting around a hinge forming the border between these two parts, said hinge being able to be composed of several elements working in bending or in traction, characterized in that:!
• a molding tool comprising a first mold and a second mold, the imprints of which are such that, once the first and second molds are assembled and locked, they define the cavity of the open part, the movable parts forming between them a large opening angle, typically close to 180 °, the first mold comprising a housing in which slides a movable element called a lock, having two lateral faces and a frontal face, capable of blocking when it is in the closed position, the flow of the first plastic material, said lock sliding in the cavity intended to receive the second plastic material;
• the first part is injected with a first plastic material, the lock being in the low position and offering, by one of its lateral faces, a obstacle to the flow of said first plastic material at the attachments of the hinge elements on the second part
• the lock is moved so that the second plastic can reach the first plastic - the first plastic being still hot, the second plastic is injected into the second part of the room.
• This method makes it possible in particular to mold, by sequential multi-material injection, a service capsule comprising a base made of a first plastic material and a cap made of a second plastic material, the cap and the base being separated from each other by a hinge comprising at
• the device chosen for the production of these service capsules comprises two injection units, and a molding tool comprising two main parts: a first and a second mold.
• a movable element which has a front wall and two side walls, slides inside the first mold so that its wall
• the molding tool comprises a first mold and a second mold, the combined impressions of which - when the two molds are locked against each other - form a cavity occupying the volume of the service capsule, cap wide open, typically at an angle of 180 ° with the base.
• the manufacturing cycle includes: - the injection of the first plastic material into the area of the first part of the capsule, the mobile part in the closed position (lock closed)
• this position determines the border between the two materials and the geometric configuration in which the two materials will come into contact. Even by choosing two materials compatible in adhesion and / or in melting temperature, it is preferable to aim for a certain interpenetration of the materials to promote adhesion. In addition, as has been done in FR 2662 144 and EP 0826606, it is advisable to place this border in an area with little mechanical stress, in particular in fatigue.
• This pressure can indeed reach several hundred bars and the lock must be guided and supported in order to be able to resist the force which tends to move it. So that the lock does not lose its role as an obstacle to the flow of the first plastic material, it is generally sought so that, at the level of the front, the side walls of said lock are surrounded over a certain height by the tool walls.
• we slide the lock in a long cavity and we want to prevent the flow of plastic in a cavity leading to this long cavity, we do slide the lock in said cavity so that its front wall arrives upstream of the crossroads with the other vein, at a distance at least equal to the thickness of the cavity at this location.
• the fatigue strength of the hinge means that the boundary between materials must not be placed exactly in the preferential flexion zone of the hinge.
• the applicant has moved, without this being too visible, the border between the materials, on the side of the fasteners on the cap of the hinge (s) and of the element (s) (s) tensioner (s).
• camber (s) and tensioning element (s) are made, in their preferential bending and traction zones, of the plastic material of the base - the capsule, which is preferably a material having good characteristics. mechanical, particularly resistant to fatigue in bending and alternating traction, typically polypropylene.
• the combined cavities of the first mold and the second mold define, when these are locked against each other, - the volume of the service capsule, cap open at 180 °.
• the lock is placed in such a way that it can slide in the cavity intended for molding the substantially vertical wall of the cap located near the base.
• the movable part slides vertically in the first mold, pressing against the walls of said first mold, and opens into the part of the cavity corresponding to the substantially vertical wall of the cap.
• FIG. 1 illustrates a first test outside the invention where the lock, in the closed position, descends deep (more than five times the thickness) into the cavity of the cap.
• the filling pressure is indeed of the order of 300 bars when the cavity is filled, and, under the effect of the force exerted on the front of the lock, the latter could, if it were not sufficiently supported, move, move back and let the plastic of the cover fill the cavity of the hinge elements.
• the surface of the attachments of the elements of the hinge on the cap and modified the shape of the lock it is no longer a simple prism matching the thickness of the wall of the cap but a three-dimensional piece, having a height, and possibly a thickness, different at the level of the tensioning element of the hinge and at the level of the film hinge.
• the slope of the oblique wall 0 of the second mold corresponding to the cavity of the attachment of the film hinge and of the tensioning element on the cap is increased substantially.
• this fastener has a height at least twice the thickness of the tensioning element.
• the lock descends until its front reaches the level of the hinge attachment, flush with the base of said oblique wall of the second tool. It is therefore not engaged in depth in the mold cavity corresponding to the vertical wall of the cap.
• the order of the injections is reversed: the base is first injected with the plastic material usually having a higher melting temperature. This material arrives in contact with a side wall of the lock, which, under the effect of the thrust can rest with its other side wall against the substantially vertical wall of the male part of the first tool intended to make the interior of the cap.
• the lock is little pressed into the cavity, its support is effective because the support is direct, without overhang and the air gap, which cannot be greater than the lateral clearance between the sliding part and the first tool is too weak for the first plastic material to be able to be introduced there easily.
• the height at the attachment of the tensioning element is equal to approximately twice the average thickness of the latter.
• the attachment of the film hinge has a height identical to that of the attachment of the tensioning element, which makes it possible to standardize the conditions of interpenetration of plastic materials at any point of the hinge. If the increase in the height of the fastener has little influence on the mechanical behavior of the film hinge, the latter already having, that is to say before the modification according to the invention, a non-uniform thickness with an area preferential bending,
• the front of the lock has a non-uniform height: when the lock is mounted in the open position, the front does not go back up inside the upper tooling but remains still slightly protruding, which allows a less abrupt transition between the relatively large thickness of the substantially vertical wall of the cap and the thickness of the fastener.
• the part of the lock remaining protruding occupies the place of a thick cap portion, which, if it had been formed with the injected plastic, would have imposed during its removal a significant deformation of the hinge and the base of the capsule, resulting in an excess thickness of said capsule base ; having the consequence of preventing the correct closure of the cap on the base.
• the lock at a height such that it can, in the closed position, close the cavity of the fastener. It suffices that the front of the lock descends slightly below the fastener since the thrust of the first plastic material is lateral and that the support can be provided by the other transverse wall, in direct support against the core of the first mold used to make the inside of the cap.
• the second plastic material can be a polyolefin - typically polyethylene or polypropylene mixed with a different charge than that of the base polypropylene - or a thermoplastic material of elastomer type or having an elastomeric behavior or a thermoplastic alloy with elastomeric behavior.
• the fact that the second plastic material may have a lower melting temperature than that of the first plastic material does not prevent a good weld between materials, no doubt because these are two successive injections brought together over time.
• the method according to the invention describes a sequential two-component injection. It goes without saying that it can be transposed to a sequential multi-material injection where the number of different materials to be injected is greater than 2 and where at least one lock is actuated between two injections.
• the object obtainable by the invention can be used for other purposes than a service capsule: it is a part comprising two parts made of a different plastic material and movable one relative to the other, pivoting around a hinge forming the border between these two parts.
• Figure 1 illustrates a section of the detail of the molding tool used in the prior art to make a service capsule, the cut being made at the film hinge which connects the base (right) and the cap (to the left).
• the classic technique used in multi-material multi-injection uses a prismatic mobile element obstructing the flow of the first plastic which fills the cap.
• FIG. 2 illustrates the appearance of the two-color service capsule obtained with the molding tools of the prior art illustrated in FIG. 1.
• FIG. 3 illustrates the appearance of the two-color service capsule obtained with the method according to the invention.
• FIG. 4 illustrates a cross-section of the detail of the molding tools according to the invention used to make a service capsule, the cut being made at the level of the film hinge which connects the base (on the right) and the cap (at left).
• FIG. 5 illustrates a section of the detail of the molding tools according to the invention used to produce a service capsule, the section being carried out at the level of the tensioning element which connects the base (on the right) and the cap (on the left).
• the two-color service capsule 1 comprises a cap 3 made of a first plastic material and a base 2 made of a second plastic material, both of which are connected together by the following hinge elements: two film hinges 4 and a tensioning element 5.
• the molding tool comprises two molds, the first mold 21 and the second mold 20.
• the first mold 21 in the extension of the substantially vertical part of the cavity 23 used for molding the cap, slides a movable part, the lock 25, the front 27 of which must descend deep into the cavity 23, several millimeters below the cavity 24 corresponding to the hinge, leaving a zone 26 not filled with the plastic of the cap.
• the two-color service capsule 11 comprises a base 12 made of a first plastic material and a cap 13 made of a second plastic material, both of which are connected together by the following hinge elements: two film hinges 14 and a tensioning element 15.
• the molding tool comprises two molds, the first mold 31 and the second mold 30.
• the base is first injected, then the cap.
• FIGS. 4 and 5 show that the lock 35 is thicker at the level of the film hinge than at the level of the tensioning element.
• the heights of the fasteners of the hinge elements have been increased and defined to be equal so as to standardize the welding conditions of plastics.
• cavity of the fastening of the film hinge and of the tensioning element 39 on the cover is increased substantially so that this fastening has a height at least twice the thickness of the tensioning element.
• the front wall 37 of the lock 35 is flush with the base of the oblique wall 40 of the second mold 30 when the lock is closed.
• the first plastic material abuts against the side wall 41 and despite the strong thrust, the lock cannot move more than the play required for sliding. In the open position, the lock does not fully rise, a part 36 remaining projecting inside the cavity.
• the capsule obtained gives an impression of frank separation between the cap and the base.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=8849276

Family Applications (1)

Country Status (10)

Families Citing this family (8)

Family Cites Families (5)

• 2000
  • 2000-04-14 FR FR0004857A patent/FR2807698B1/fr not_active Expired - Fee Related
• 2001
  • 2001-04-09 AR ARP010101675A patent/AR027784A1/es unknown
  • 2001-04-10 RU RU2002130501/15A patent/RU2222427C1/ru not_active IP Right Cessation
  • 2001-04-10 PL PL01357867A patent/PL357867A1/xx unknown
  • 2001-04-10 US US10/257,522 patent/US20030178744A1/en not_active Abandoned
  • 2001-04-10 EP EP01923772A patent/EP1272326A1/de not_active Withdrawn
  • 2001-04-10 AU AU2001250463A patent/AU2001250463A1/en not_active Abandoned
  • 2001-04-10 WO PCT/FR2001/001084 patent/WO2001078958A1/fr not_active Application Discontinuation
  • 2001-04-10 MX MXPA02010024A patent/MXPA02010024A/es unknown
  • 2001-04-10 BR BR0110026-2A patent/BR0110026A/pt not_active Application Discontinuation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events