Method for overmolding molds and tableware containers

Abstract

According to a first aspect of the present invention, the present invention provides a mold for injection molding overmolding a tableware container using a silicone-containing material, the mold comprising a female part and a male part, The female part is, A cavity configured to receive the first surface of the dish container during overmolding, Includes an injection nozzle configured to allow a silicone-containing material to be injected into a cavity on the first surface, Oobe is, A central stud formed from a material having a Shore D hardness in the range of 50 to 60, or including a coating of a material having a Shore D hardness in the range of 50 to 60, and configured to receive the second surface of a tableware container, A peripheral seal formed from a material with a Shore A hardness in the range of 50 to 60, configured to receive the edge of a tableware container, comprising a peripheral seal extending circumferentially around a central stud, It includes a molding recess extending circumferentially between the central stud and the peripheral seal, The molding recess and surrounding seal are adapted to allow the edge portion to move during overmolding.

Description

Technical Field

[0001] The present disclosure relates to the field of overmolding of tableware containers, particularly to overmolding food containers using flexible materials.

Background Art

[0002] In collective catering facilities such as school and university cafeterias and residential facilities for the elderly, the use of tableware generates a significant amount of noise due to impacts between the tableware. This not only causes inconvenience to the facility users but also has an adverse effect on the health of the employees. The employees are exposed to this noise for several hours a day at the workplace.

[0003] In fact, studies have shown that the frequency of the impact sound between tableware reaches a high value exceeding 1.5 kHz. This has an adverse effect on human comfort and health. Therefore, being exposed to sounds of such frequencies for a long time becomes a realistic public health problem.

[0004] To reduce the noise caused by these impacts, it is known to use tableware covered with a flexible material such as silicone. Advantageously, two methods enable the production of two-material tableware containing silicone. First, the tableware can be sprayed with silicone by room temperature vulcanization (RTV). This method involves applying or spraying a plasticizable silicone to cover the tableware and then effectively crosslinking or curing the silicone at room temperature. However, RTV silicone has a high viscosity even at room temperature and is not suitable for rapid and precise overmolding of tableware. Especially when the shape of the tableware is complex, the material takes a considerable amount of time to cover the tableware and cannot accurately follow the shape. There may be a need to post-process the tableware to obtain the desired finished product after overmolding. As a result, material waste occurs, along with unwanted contamination and production costs. Furthermore, the time required for crosslinking of RTV silicone can span several days, and such a method is inappropriate for tableware production on an industrial scale.

[0005] Another method in the manufacture of two-material tableware is injection molding of liquid silicone rubber (LSR). This material has the advantage of exhibiting high thixotropy when subjected to shear stress—such as during pressurized injection into a mold. Its viscosity rapidly decreases, and it becomes liquid. This allows the material to expand rapidly while incorporating the shape given by the mold and the tableware. Furthermore, LSR can undergo a cross-linking reaction much faster than RTV silicone, usually in less than a minute, thus significantly reducing the time required for overmolding the tableware. This type of method is performed in molds made of hard materials such as steel to prevent damage to the mold during use. Also, tolerances between the mold and the fins (protrusions) of the container are avoided as much as possible. [Overview of the Initiative]

[0006] However, for industrial-scale production, it is preferable to use tempered glass tableware. This is because it is cheaper and lighter than tableware made from materials such as ceramic or pottery. The heat-strengthening process of glass gives it mechanical strength suitable for food use, but it results in deformation of the tableware. Tempered tableware will have variations of several millimeters in diameter and height—that is, it will not be perfectly round or perfectly flat like porcelain or pottery tableware. This variation in size makes tempered glass tableware unsuitable for known injection molding overmolding methods such as LSR. The tableware will crack or break due to the high pressure it will experience during injection—reaching up to approximately 700 bar. This high pressure is necessary to minimize the production cycle time of the tableware containers, as the required injection time is inversely proportional to the injection pressure. Furthermore, this pressure and the resulting reduction in injection time are essential to prevent the silicone from crosslinking when it comes into contact with the mold due to the high temperature of the mold.

[0007] One of the objectives of this application is to provide a mold and method for overmolding tempered glass tableware that is suitable for tempered glass tableware and accommodates the sizing inconsistencies present therein. This enables overmolding without the tableware breaking.

[0008] Another object of this application is to provide a seal between a container and a mold that is satisfactory for LSR injection despite such non-uniformity in the size of the container.

[0009] Another object of this application is to provide a mold and method that enables the rapid and accurate overmolding of tableware despite such sizing inconsistencies.

[0010] Another objective of this application is to provide molds and manufacturing methods suitable for industrial-scale production, which enable the manufacture of silent tableware, particularly intended for use in group catering facilities.

[0011] For this purpose, according to a first aspect, the present disclosure relates to a mold for injection molding overmolding a tableware container using a silicone-containing material, wherein the mold comprises a female part and a male part, The female part is, A cavity configured to receive the first surface of the dish container during overmolding, Includes an injection nozzle configured to allow a silicone-containing material to be injected into a cavity on the first surface, Oobe is, A central stud formed from a material having a Shore D hardness in the range of 50 to 60, or including a coating of a material having a Shore D hardness in the range of 50 to 60, and configured to receive the second surface of a tableware container, A peripheral seal formed from a material with a Shore A hardness in the range of 50 to 60, configured to receive the edge of a tableware container, comprising a peripheral seal extending circumferentially around a central stud, It includes a molding recess extending circumferentially between the central stud and the peripheral seal, The molding recess and surrounding seal are designed to allow the edge portion to move during overmolding.

[0012] Therefore, the container is sufficiently free to move so as not to be subjected to stress exceeding its mechanical strength. At the same time, it is supported in such a way that the force is distributed across the entire surface, avoiding localized excessive stress. Furthermore, it exhibits a seal with the mold sufficient for the injection of liquid silicone.

[0013] According to one embodiment, the system further comprises a vacuum pump connected to a central orifice that opens into the central region of the central stud, thereby holding the second surface to the central stud by suction.

[0014] According to one embodiment, the device further comprises a vacuum suction system that opens into the female portion, the female portion facing either the first surface or the male portion.

[0015] According to one embodiment, the peripheral seal and / or central stud comprises a non-stick material, such as polytetrafluoroethylene, or a material covered with a coating comprising a non-stick material, such as polytetrafluoroethylene.

[0016] According to one embodiment, the peripheral seal and / or molding recess is adapted to allow the edge portion to move by less than 3 mm, preferably 1 mm to 3 mm, and more preferably 1 mm to 2 mm.

[0017] According to one embodiment, the device includes at least one extruder positioned inside the cavity of the female part, which is capable of moving the container out of the cavity by pressing a first surface against it.

[0018] According to one embodiment, at least one extruder extends around the entire circumference of the cavity.

[0019] According to a second aspect, the disclosure relates to a method for overmolding a tableware container using a silicone-containing material, a) A step of positioning a container within the mold described above, wherein the second face of the container is placed on the central stud and the edge portion of the container is received by the peripheral seal; b) A step of closing the mold by moving the female part so as to face the male part, and holding the container between the female part and the male part; c) A step of injecting a material containing silicone through an injection nozzle until the first face is covered with the material; d) A step of opening the mold and taking out the container.

[0020] According to one embodiment, further comprising a step of performing vacuum suction on the air between the second face and the central stud by a vacuum pump, the vacuum pump being connected to a central orifice opened into the central region of the central stud, thereby holding the second face of the container on the central stud.

[0021] According to one embodiment, further comprising a step of performing vacuum suction on the air between the first face and the cavity by a vacuum suction system, thereby facilitating injecting the material containing silicone into the cavity.

[0022] According to one embodiment, before or during the step of opening the mold, comprising a step of moving the first face of the container away from the female part, the moving step being performed by operating an ejector disposed in the cavity of the female part.

[0023] According to one embodiment of the method, the tableware container is a tempered glass container.

[0024] According to one embodiment of the method, the container is a plate or a ramikin.

Brief Description of the Drawings

[0025] Other features, objectives, and advantages will become apparent from the following description. This description is illustrative only and not limiting, and is to be read with reference to the accompanying drawings. As follows.

[0026] [Figure 1] Schematically shows a tableware container obtained by the proposed overmolding method. [Figure 2] Schematically shows the proposed mold. [Figure 3] Schematically shows a method for overmolding the proposed tableware container.

Embodiments for Carrying Out the Invention

[0027] According to a first aspect, an injection molding overmold tool is proposed. Referring to FIG. 1, a general tableware container (a vessel that is tableware, RECIPIENT DE VAISSELLE) is shown. Such a container (vessel, utensil) 20 includes a first surface 21 intended to be placed on a table or tray and a second surface 22 for receiving food that is on or in the container. The container 20 further includes an edge portion 23 that extends circumferentially (in a circumferential direction, along the circumference) around a central portion 24. The edge portion 23 may extend parallel to the central portion 24 in the case of a flat plate, and may form an angle that is larger or smaller with respect to this central portion 24. Also, the central portion 24 and / or the edge portion 23 may be at least partially curved, for example, in the case of a bowl or a ramikin.

[0028] FIG. 2 shows the proposed mold 10. This includes a male part 11 and a female part 12. The female part 12 is provided with a cavity 13 configured to receive the first surface 21 of the tableware container 20 during use. On the other hand, the male part 11 is provided with a central stud 1 configured to receive the second surface 22 of the container 20.

[0029] The main spindle X of the mold is defined as an axis that is perpendicular on the one hand to the plane formed by the surface of the female part 12 on which the cavity 13 is located, and perpendicular on the other hand to the plane formed by the surface of the male part 11 on which the stud 1 rests. Furthermore, the main spindle X passes through the centers of the cavity 13 and the stud 1, respectively. This main spindle also defines the opening and closing direction of the mold.

[0030] Naturally, the shapes of the cavity and studs are to be adapted to the shape of the container 20 that is to be overmolded. For this purpose, if it is necessary to overmolde containers of different shapes, multiple separate molds 10 may be used.

[0031] The female part 12 includes an injection nozzle 9, which enables the injection of a silicone-containing material into the cavity 13, thereby covering the first surface 21 with the aforementioned material. Preferably, the nozzle 10 is located in the center of the cavity 13, but may be located in another position that allows it to open into the cavity 13.

[0032] The central stud 1 of the male part 11 is formed of a flexible material having a sufficiently low coefficient of friction to allow movement of the container 20. Flexible means a material with a Shore D hardness in the range of 50 to 60. Alternatively, the central stud 1 may be formed of a harder material, but may be covered with a coating having a sufficiently low coefficient of friction to allow movement of the container 20, and having a Shore D hardness in the range of 50 to 60. These mechanical properties allow the surface of the central stud 1 to receive the second surface 22 of the container 20, enabling movement of the container 20 perpendicular to the main axis X of the mold 10. This naturally positions the container 20 so that the force from the injection pressure is distributed across its entire surface. The risk of locally concentrated forces that could damage the container 20 is minimized.

[0033] For the reasons mentioned above, mold 10 is particularly suitable for overmolding tempered glass containers 20 that have non-uniform size in the three axial directions.

[0034] According to one embodiment, the central stud 1 comprises a non-stick material, such as polytetrafluoroethylene (PTFE), also known as Teflon®. Furthermore, the central stud 1 may be composed of another material with a non-stick coating.

[0035] A peripheral seal 3 extends from the surface of the male part 11 that receives the stud 1 along the circumference centered on the main spindle X, at a distance greater from the main spindle X than the distance corresponding to the circumference of the stud 1. The function of this peripheral seal is to support the edge portion 23 of the dish container 20 when the dish container 20 is placed in the mold 10. Similar to the stud 1, the seal 3 is made of a flexible material and has a Shore A hardness in the range of 50 to 60. In the same manner as with the stud 1, the flexibility of the peripheral seal 3 allows the edge portion 23 of the container 20 to move during overmolding, and distributes the forces acting on the surface of the container 20 as optimally as possible.

[0036] According to one embodiment, the peripheral seal 3 includes a non-stick material, such as polytetrafluoroethylene (PTFE), also known as Teflon®. Furthermore, the peripheral seal 3 may be composed of another material with a non-stick coating. This property has the advantage of preventing the edges 23 of the container 20 from adhering to the peripheral seal 3, thereby facilitating the removal of the container 20 from the mold 10 after overmolding.

[0037] Between the stud 1 and the seal 3, the surface of the male part 11 forms a molding recess 2. That is, of the edge portion 23 of the container 20, the portion located between the stud 1 and the peripheral seal 3 in a direction perpendicular to the main axis X does not directly contact the male part 11 because the molding recess 2 is located between this portion of the edge portion 23 and the surface of the male part 11. Therefore, the molding recess 2, together with the peripheral seal 3 and the stud 1, contributes to allowing the container 20 to move during overmolding.

[0038] The peripheral seal 3 and / or molding recess 2 may be adapted to allow the edge portion 23 to move by less than 3 mm, preferably 1 mm to 3 mm, and more preferably 1 mm to 2 mm.

[0039] The mold 10 includes a closing system that allows the male part 11 and the female part 12 to move relative to each other. The closing system may be capable of moving the male part 11 and / or the female part 12. In particular, the closing system may include jacks such as hydraulic jacks or pneumatic jacks. The mold 10 may be a horizontal press mold, i.e., a mold in which the jacks are positioned horizontally and the surfaces of the male part 11 and the female part 12 extend in a vertical plane. Alternatively, the mold 10 may be a vertical press mold, i.e., a mold in which the jacks are positioned vertically and the surfaces of the male part 11 and the female part 12 extend in a horizontal plane.

[0040] According to a particular embodiment, after the dish (ASSIETTE) is placed in the mold 10, the mold 10 may be equipped with a vacuum pump 5 to hold the second surface 22 of the container 20 against the central stud 1 by suction. This vacuum pump 5 is particularly suitable when the mold 10 is a horizontal press mold, because the surfaces 21 and 22 of the container are located on a vertical plane when placed inside the mold. Therefore, it is necessary to ensure that the container 20 is pressed against the stud 1 when the mold 10 is not in a completely closed position. However, such a vacuum pump 5 may also be provided when the mold 10 is a vertical press mold.

[0041] The vacuum pump 5 is connected to an orifice 7 that opens into the stud 1, preferably at the center of the stud. If the vacuum pump 5 is installed at a certain distance from the stud 1, a conduit 6 may be provided to connect the pump 5 and the orifice 7.

[0042] Another embodiment for pressing the second surface 22 of the container against the central stud 1 includes a support seal (bearing seal) 15 positioned on the central stud. The support seal 15 is a circular seal positioned on the surface of the central stud 1, with the main shaft X as its center. This seal has adhesive properties and can ensure that the second surface 22 is held against the central stud 1, even if the mold 10 is a horizontal press mold.

[0043] The two embodiments described above may be combined. A central stud 1 including an orifice 7 connected to the vacuum pump 5 and a support seal 15 may be provided.

[0044] The mold 10 may include a vacuum suction system 4. This system is open to (connected to) the female part 12, which is positioned to directly face the first surface 21 of the container 20 or to face the male part 11 when the container 20 is placed inside the mold 10. The vacuum suction system 4 allows for a reduction in the air pressure between the container 20 and the female part 12, thereby facilitating the injection of silicone through the nozzle 9.

[0045] When the surface area of ​​the lower surface 21 of the container 20 is large, there is a risk that the injected material will adhere not only to the container 20 but also to the cavity 13 and female part 12. While it is possible to detach the injected material from the cavity 13 and female part 12 by applying chemicals or soapy water, the effectiveness is inconsistent. Therefore, according to one embodiment, the mold comprises one or more extruders 14, one or more of which are positioned within the cavity 13 and can move the container 20 out of the cavity 13. These may be multiple extruders 14, or a single circular extruder centered on the spindle X and extending around the entire circumference of the cavity 13. This eliminates the need to use special products to detach the material and reduces the operating costs of the mold. Furthermore, this embodiment has the advantage of being easily automated—only the extruders 14 need to be activated when it is necessary to separate the container 20 from the mold 10—and is therefore suitable for industrial-scale use.

[0046] Furthermore, a method 100 is proposed for overmolding a tableware container 20 using a silicone-containing material within the mold 10 described above. Referring to Figure 3, in the most common embodiment, this method comprises a step 101 of positioning the container 20 in the mold 10, where the second surface 22 of the container 20 is positioned on the central stud 1 and the peripheral seal 3 receives the edge portion 23 of the container 20. After positioning the container 20, a closing step 102 is performed, in which the female portion 12 faces the male portion 11 by activating a system for closing the mold 10. The container is then held between the male portion 11 and the female portion 12 and does not move until the injection of the material begins. Subsequently, a step 105 is performed in which a silicone-containing material, preferably liquid silicone rubber, is injected through an injection nozzle 9 located in the female portion 12, thereby covering the entire first surface 21 with the injected material. During the injection step, due to the characteristics of the mold 10 described above, the container 20 is free to take positions that reduce local forces. Finally, step 107 is performed to open the mold 10, making it possible to remove the container 20 from the mold 10.

[0047] After the positioning step 101, the edge portion 23 of the container 20 does not need to reach the end of the peripheral seal 3 at the position furthest from the main spindle X along its entire circumference. Because the size of the container is variable, the edge portion 23 does not need to reach the same position on the peripheral seal 3 along the entire circumference of the container 20. Therefore, it becomes possible to inject an even thicker material layer at the circumferential position where the diameter of the container 20 decreases. This results in an overmolded container with a substantially uniform diameter after performing the overmolding method 100.

[0048] The type of material injected through the injection nozzle 9 directly affects the quality of the resulting overmolded container 20. According to one embodiment, the material injected in injection step 105 is a self-adhesive liquid silicone rubber. This ensures that a tableware container 20 is obtained in which satisfactory intermolecular cohesive forces are obtained between the injection-molded silicone and the material that forms the container 20 before the overmolding method 100 is performed.

[0049] In one implementation of this method, if the male part 11 of the mold 10 includes a vacuum pump 5, a vacuum suction step 103 is performed before the injection step 105. This is done after the closure 102 of the mold 10, or immediately after the positioning 101 of the container 20 to the central stud 1, in particular, when the mold 10 is a horizontal press mold and the container 20 cannot be held to the central stud 1 without vacuum suction, to hold the second surface 22 of the container 20 to the central stud 1.

[0050] In another implementation, if the female part 12 includes a vacuum suction system 4, the method may include a vacuum suction step 104 using the vacuum suction system 4 to create a vacuum in the air between the first surface 21 and the cavity 13. This reduces the pressure between the first surface 21 and the cavity 13 as much as possible, facilitating the movement of the injection material covering the first surface 21. This reduces the time required for the injection step 105 and avoids premature bridging of the injection material. The vacuum suction step 104 by the vacuum suction system 4 is performed after the mold closing step 102 and before or after any possible vacuum suction step 103 by the vacuum pump 5.

[0051] In one implementation of this method, the step 106 of moving the first surface 21 of the container 20 away from the female part 12 is performed either after the mold opening step 107 of the mold 10, or optionally during the mold opening step 107. The separating movement 106 is achieved by operating an extruder 14 located in the cavity 13 of the female part 12.

Claims

1. A mold for injection molding overmolding a tableware container using a silicone-containing material, wherein the mold comprises a female part and a male part, The female part is, A cavity configured to receive the first surface of the tableware container during overmolding, The invention includes an injection nozzle configured to enable the injection of the silicone-containing material into the cavity on the first surface, The aforementioned male part is, A central stud formed from a material having a Shore D hardness in the range of 50 to 60, or including a coating of a material having a Shore D hardness in the range of 50 to 60, and configured to receive the second surface of the tableware container, A peripheral seal formed from a material having a Shore A hardness in the range of 50 to 60, configured to receive the edge portion of the tableware container, comprising a peripheral seal extending circumferentially around the central stud, The central stud and the peripheral seal include a molding recess extending in the circumferential direction, The molding recess and the surrounding seal are adapted to allow the edge portion to move during overmolding. Mold.

2. Furthermore, the mold according to claim 1 is further equipped with a vacuum pump connected to a central orifice that opens into the central region of the central stud, thereby holding the second surface to the central stud by suction.

3. Furthermore, the mold according to claim 1, comprising a vacuum suction system that opens into the female portion, wherein the female portion faces the first surface or faces the male portion.

4. The mold according to any one of claims 1 to 3, wherein the peripheral seal and / or the central stud comprises a non-stick material, such as polytetrafluoroethylene, or a material covered with a coating comprising a non-stick material, such as polytetrafluoroethylene.

5. The mold according to any one of claims 1 to 3, wherein the peripheral seal and / or the molding recess is adapted to allow the edge portion to move by less than 3 mm, preferably 1 mm to 3 mm, and more preferably 1 mm to 2 mm.

6. The mold according to any one of claims 1 to 3, comprising at least one extruder disposed in the cavity of the female part and capable of moving the container out of the cavity by pressing the first surface.

7. The mold according to claim 6, wherein at least one of the extruders extends around the entire circumference of the cavity.

8. A method for overmolding a tableware container using a silicone-containing material, a) A step of positioning a container in the mold according to claim 1, wherein the second surface of the container is placed on the central stud and the edge portion of the container is received by the peripheral seal, b) A step of closing the mold by moving the female part so that it faces the male part, and holding the container between the female part and the male part, c) The step of injecting the material containing silicone through an injection nozzle until the first surface is covered with the material, d) A method of overmolding, comprising the steps of opening the mold and removing the container.

9. The overmolding method according to claim 8, further comprising the step of using a vacuum pump to create a vacuum suction of the air between the second surface and the central stud, wherein the vacuum pump is connected to a central orifice that opens into the central region of the central stud, thereby holding the second surface of the container against the central stud.

10. The overmolding method according to claim 8, further comprising the step of using a vacuum suction system to create a vacuum suction in the air between the first surface and the cavity, thereby facilitating the injection of the silicone-containing material into the cavity.

11. The overmolding method according to any one of claims 8 to 10, further comprising a step of moving the first surface of the container away from the female part before or during the step of opening the mold, wherein the step of moving is carried out by operating an extruder located in the cavity of the female part.

12. The overmolding method according to any one of claims 8 to 10, wherein the tableware container is a tempered glass container.

13. The overmolding method according to any one of claims 8 to 10, wherein the container is a dish or a ramekin.

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