JP2012171629A - Method and device of manufacturing foamed resin container and foamed resin container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a foamed resin container, in which a strength necessary part is integrally molded by lowering the expansion ratio thereof compared to that of other part, efficiently in a balanced manner as a whole.SOLUTION: Two kinds of foaming resin particles moldable with different expansion ratios are used. When they are filled in a cavity of a molding die, the foaming resin particle a1 on the low expansion ratio side is sucked and retained in a prescribed part equivalent to the strength necessary part in the cavity 25, and then, the foaming resin particle a2 on the high expansion ratio side is filled in the other part. In this state, steam is blown for performing heat foam molding, thereby integrally molding the container in which the expansion ratio of the entire thickness of the strength necessary part is lower than that of the other part.

Description

  The present invention relates to a method and apparatus for producing a foamed resin container that is suitably used for transporting, storing, and the like of various agricultural products, and particularly for transporting in a cold state, and a foamed resin container produced thereby.

  Conventionally, as a container used for transportation, storage, etc. of fruits and vegetables and other various agricultural products, particularly agricultural products that need to be kept cold, a flat rectangular container body opened upward, and a lid fitted to the opening end of the container A container made of foamed resin such as polystyrene foam is used.

  In handling such as transportation and storage in the state of storing such agricultural products in such containers, there are cases where they are stacked in multiple stages, and when force is applied to pull the side walls outward when taking in or out agricultural products, etc. Therefore, the side walls are required to have the strength to withstand stacking loads and the tensile strength, and to have the bottom strength without the possibility of bottoming out when handling the packaged items. Desired.

  On the other hand, it is required to reduce the wall thickness and weight from the viewpoint of facilitating handling such as stacking and loading of containers with agricultural products stored, and cost reduction by saving materials. Yes. However, if the wall thickness of the container side wall is reduced, the required strength cannot be obtained. For this reason, it is difficult to achieve both maintenance of container strength and weight reduction, and there is a demand for a solution.

  In order to save materials and reduce the weight without reducing the side wall strength and bottom strength, for example, for the side walls, the inner surface of the central region excluding the vicinity of the corner, By forming the corrugated irregularities with the convex stripes between the concave stripes, the ribs are partially thinned by the concave stripes while maintaining a predetermined strength, and the bottom is rib-like convex on at least one of the upper and lower surfaces. It has been proposed to save the material while maintaining a predetermined strength in a honeycomb shape provided with a large number of planar hexagonal recesses defined by the portions.

  In the case of the proposed corrugated side wall, as a result of the compression test in which pressure is applied from the top of the container and the tensile test in the opening direction of the opening end, the compressive load and the tensile load are dispersed in the corner portion. Although it had a strength comparable to or higher than that of a normal side wall having no irregularities, when a larger load was applied, destruction such as cracks finally occurred at or near the corner. Further, the bottom portion having a honeycomb shape has a strength comparable to or more than that of a normal bottom portion by dispersing the load in the corner portion as a result of the bottom portion pressing test. When a load was applied, the destruction finally occurred in the corner portion or in the vicinity of the corner.

  That is, in the case of the foamed resin container, even when the above-described uneven wave shape or honeycomb-shaped strength holding structure is adopted for the side wall or the bottom part, the container is most used, for example, when stacking or taking out stored items. It is desired to increase the strength of the corner portion where the load is applied and the vicinity thereof.

  Therefore, by using a different magnification foam molding method that integrally molds the parts that require strength when using the container with low-magnification foaming and other parts that do not apply load with high-magnification foaming, The strength required portion such as the vicinity is reinforced without changing the thickness or shape so as not to affect the capacity or the like of the container.

  Conventionally, for example, Patent Literature 1 and Patent Literature 2 are known as those that reinforce a part of a foamed molded product by different magnification foam molding.

  In Patent Document 1, a part of a molded product is blocked by a blocking member inside a cavity of a molding die, and the first raw material (expandable resin particles) is filled in the part and heated, and heat melting is performed. Release the blocking state by the blocking member until the completion of wearing, fill the remaining part with the second raw material (expandable resin particles), and heat-foam molding. Molding mold to block part In addition, it is necessary to configure a part of the movable part in a movable manner, and it is necessary to perform heating in two stages, the structure is complicated, and it is difficult to obtain a plurality of parts.

  In the case of Patent Document 2, two types of expandable beads that can be molded with different expansion ratios are used as raw materials, and one type of expandable bead that molds a part of a foam molded product is used as a foam mold. After adhering to the desired part of the material, it is filled with different kinds of expandable beads forming the other part and heated and foam-molded. One kind of expandable beads is injected into the cavity in a certain amount. Therefore, when there are a plurality of portions where the expandable beads are attached, such as the corner portions of the four corners, it is difficult to make the same amount of the expandable beads attached to each portion. There is a difference in the adhesion amount and the adhesion form for each corner portion, and molding in this state may cause a deterioration in the weight balance of the foam molded product. In addition, the expandable beads that cannot adhere to the suction adhering portion fall to the bottom and are mixed with different types of expandable beads to be filled next.

Japanese Patent Laid-Open No. 60-40372 JP 7-308930 A

  The present invention has been made in view of the above, and particularly in foamed resin containers used for agricultural products and the like, it is the most necessary part when using containers, for example, when stacking or taking out packaged items. A foamed resin container that maintains the required strength by integrally forming the required strength parts such as the corners, where the force is applied, lower than the other parts is molded efficiently and in a balanced manner as a whole The manufacturing method and manufacturing apparatus which can be performed are provided, and also the foamed resin container obtained by this is provided.

  The method for producing a foamed resin container according to the present invention comprises filling a foaming resin particle into a cavity of a molding die comprising a male mold for molding the inner surface of the container and a female mold for molding the outer surface of the container. In the method for producing a foamed resin container in which a part requiring strength is formed by foaming lower than the other part, at least one of a male mold and a female mold is provided with a number of communication holes penetrating from the mold to the molding surface, and the strength At least two types of foaming properties that can be molded at different foaming ratios by providing partial suction means for sucking and holding the foamable resin particles as raw materials through the communicating holes at predetermined molding sites for molding the necessary portions. In the filling step using resin particles, first, the low-expansion expanded foamable resin particles used for the strength required portion are equivalent to the strength required portion in the cavity by the partial suction means of the predetermined molding site. The part is sucked and held, and then, the high-expanded foam side expandable resin particles used in the other part are filled in the other part in the cavity, and at least two kinds of expandable resin particles are filled in the cavity. In this state, steam is blown in and foamed by heating, and a container having a foam thickness lower than that of the other part is integrally formed by integrally molding the part requiring the strength.

  As a result, a foamed resin container in which the entire thickness of the necessary strength part for use in the container, for example, the required thickness part such as the corner part, is formed by lowering foaming than the other part and the strength is higher than the other part. It can be efficiently manufactured by one-time heat foaming.

  In the above, after the low-expansion foam side expandable resin particles are sucked and held in the predetermined portion in the front cavity, the high-expansion foam side expandable resin particles are filled with the suction hold state maintained. preferable.

  In the method for producing a foamed resin container, when the low-expanded foam side foamable resin particles are sucked and held in a predetermined portion in the cavity, the foamable resin particles are once filled in the entire cavity, and then It is preferable that the predetermined portion is sucked and held by discharging excess foamable resin particles filled in the other portion while continuing suction by the partial suction means of the predetermined molding portion. Thereby, when a predetermined portion corresponding to a plurality of strength required portions is set in the cavity, each of the predetermined portions can be surely held in the aggregated state by the substantially same amount of expandable resin particles. And a plurality of strength required parts can be formed in a balanced manner.

  In the method for manufacturing a foamed resin container, air is blown into a cavity from a communication hole provided in another molding site, and is sucked and discharged from a filling port or a discharge port provided separately from the filling port. Thereby, the surplus foamable resin particle with which the other part was filled can be discharged | emitted reliably. Further, air in a separate circuit is blown at the boundary between the predetermined portion and the other portion in the cavity, and the excess foamable resin particles are blown off and discharged. As a result, it is possible to suck and hold substantially the same amount of expandable resin particles by the partial suction means provided with the low-expanded foam side expandable resin particles at each predetermined molding site, and to each predetermined portion in the cavity. The foamable resin particles can be reliably held by suction. For this reason, a foamed resin container having a good weight balance can be obtained.

  The strength-required portion is a corner portion of a flat rectangular container, and foamable resin particles on the low-magnification foam side are sucked and held in a predetermined portion corresponding to the container corner portion in the cavity, and then foamed on the high-magnification foam side. The conductive resin particles are filled so as to be sucked and held in a portion other than the portion corresponding to the corner portion in the cavity, and then heated and foam-molded. Thereby, the foamed resin container which reinforce | strengthened the corner part which becomes most forceful at the time of stacking, taking out the package, etc. on the use of the container can be manufactured.

  In the method for manufacturing a foamed resin container, when a plurality of strength required portions of different magnifications are set in the foamed resin container to be manufactured, for each predetermined molding site for molding the strength required portions of different magnifications, Sequentially, by each partial suction means, the foamable resin particles for molding each required strength part are sucked and held in a predetermined part corresponding to each required strength part in the cavity, and then the other part of the foamable resin particles is filled. Thus, heat foaming can be performed. Thereby, a some intensity | strength required part can be shape | molded by making a magnification lower than each other part, and mutually different magnification.

  In addition, the present invention fills a foaming resin particle in a cavity of a molding die comprising a male mold that molds the inner surface of the container and a female mold that molds the outer surface of the container. In the apparatus for manufacturing a foamed resin container that is molded by lower foaming, each of the male mold and the female mold has a large number of communication holes that penetrate from the inner space of the mold to the molding surface, and at least one of the required strength portions A partial suction means for sucking and holding the expandable resin particles through the communication hole is provided in a predetermined molding portion for molding the resin so as to be sucked by a separate circuit from the intake / exhaust means of the other molding portion. One or the other of the female mold and the female mold is provided with a filling port for injecting and filling at least two kinds of expandable resin particles that can be molded with different expansion ratios into the cavities.

  In the manufacturing apparatus, as the partial suction means for the predetermined molding portion of at least one of the male mold and the female die, a region including the communication hole of the predetermined molding portion in the inner space is separated from the other portion by the partition wall. The suction chamber is formed as a suction chamber, and a suction pipe constituting a suction line different from the suction / exhaust means of other molding parts is connected to the suction chamber.

  In the manufacturing apparatus, the male mold constituting the molding die may be provided with partial suction means for the predetermined molding site.

  Further, according to the present invention, at least two kinds of expandable resin particles that can be molded with different expansion ratios are filled in the cavity of the molding die by any one of the manufacturing methods of the above-described inventions, and integrally heated and foamed. This is a container made of foamed resin, characterized in that the entire thickness of the required strength portion in use of the container is molded by lowering foaming than other parts.

  In the foamed resin container, the strength-required part of the container is a corner part of a flat rectangular container body, and the area near the corner is integrally formed of a foamed resin that is low in comparison with other parts. It can be. Also, a plurality of strength-required portions having different magnifications and lower magnification than other portions may be set.

  As described above, according to the method and apparatus for producing a foamed resin container of the present invention, a part requiring strength particularly in use of the container, for example, the entire thickness of the corner part is formed by lowering foaming than other parts. Therefore, it is possible to obtain a foamed resin container having a pressure resistance that can withstand stacking without increasing the thickness or changing the capacity.

  In particular, when the foamable resin particles on the low-magnification-foamed side for molding the strength-required portion are sucked and held in a predetermined portion in the cavity, the foamable resin particles are once filled in the entire cavity, and the portion of the predetermined molding portion When the surplus foamable resin particles in other portions are positively discharged while being sucked and held by the suction means, each predetermined portion corresponding to the strength required portion in the cavity has almost the same predetermined amount of foaming. The photosensitive resin particles can be surely sucked and held, and can be held without causing a large difference in the holding amount for each predetermined portion. As a result, strength-required portions such as low-foamed corner portions in a heat-foamed container are almost equalized, and a container having stable strength as a whole and having a good weight balance can be obtained.

It is sectional drawing of the mold open state which shows the outline of the manufacturing apparatus containing the shaping die used for the manufacturing method of this invention. It is sectional drawing of a mold closing state same as the above. It is sectional drawing of the L1-L1 line same as the above. It is a partial expanded sectional view of the state where the foamable resin particles are sucked and held in a predetermined part for molding the corner region. It is sectional drawing of the L2-L2 line same as the above. In the manufacturing method of the present invention, when the female mold and the male mold are closed (a), when the first expandable resin particles are filled (b), when the excess is discharged (c), and the second expandability It is a schematic cross-sectional explanatory drawing of each process at the time of filling (d) of resin particles, at the time of thermoforming by steam supply (e), and at the time of mold release (f). It is a perspective view which shows the basic form of the container manufactured by this invention. It is the perspective view which the container main body and cover which show the practical example of the container made from a foamed resin manufactured by this invention isolate | separated. It is a top view of a container main body same as the above. It is a half vertical front view of a container main body and a cover body same as the above.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  1-6 has shown the outline of the manufacturing apparatus for enforcing the manufacturing method of the foamed resin container of this invention, and the manufacturing process by this. In this embodiment, for example, a container that is used as a container body in combination with a lid or is used alone without a lid, and has a box-like rectangular shape shown in FIG. 7 that includes a bottom 51 and four side walls 52. The case where the container 50 is manufactured by foam molding using thermoplastic foamable resin particles such as polystyrene resin as a raw material is described as an example.

  In the present invention, at least two types of expandable resin particles that can be molded mainly with the same resin and having different expansion ratios, for example, the first expandable resin particles a1 having a low expansion ratio and the second expandable resin on the high expansion ratio side. Using the two types of foamable resin particles together with the particles a2, the entire thickness of the corner vicinity region 54 including the corner portion 53 of the container 50, for example, the central portion region of the side wall 52 is used. 52a and the inner part area | region of the bottom part 51, etc. WHEREIN: It shape | molds so that it may become low expansion foam. The corner vicinity region 54 to be low-foamed foam may be only the corner portion 53, but in practice, in addition to the corner portion 53 as shown in the figure, the side wall side excluding the central region 52a of the sidewall 52 It is more preferable to include the end portions and the regions of the four corners of the bottom portion 51 in order to maintain pressure resistance and tensile strength.

  FIG. 1 shows a state in which the female mold 10 and the male mold 30 of the molding die are opened, and FIG. 2 shows a closed state of the female mold 10 and the male mold 30.

  The female mold 10 has a concave mold portion 11 having a shape corresponding to the outer surface shape of the container 50 to be molded, and the concave mold portion 11 has a molding surface from the inner space (chamber) 10a, that is, as shown in FIG. A plurality of communication holes 13 penetrating through the mold surface on the cavity 25 side formed by closing the female mold 10 and the male mold 30 are provided substantially over the entire surface at a predetermined interval. The communication holes 13 are provided with small-diameter pores or narrow slits at predetermined intervals that do not allow the raw foam resin particles to enter. The female mold 10 includes a steam supply pipe 14 and a drain pipe 15 communicating with each other via an opening / closing valve, and a pipe as an intake / exhaust means for sucking or exhausting air or steam when filling the raw material or when heating steam is introduced. 16 is disposed, and an exhaust valve 17 is disposed separately from the pipe 16. Although illustration is omitted, an air supply pipe for releasing and a supply pipe for cooling water are also provided. As the intake / exhaust means, the pipe 16 may be omitted, and the drain pipe 15 may be branched in the middle of the piping to also serve as the intake / exhaust means. Further, the intake / exhaust means can be omitted.

  The female mold 10 is provided with a filling port 18 for supplying foaming resin particles as a raw material of the foaming resin and filling the cavity 25. In the case of the present invention, at least two types that can be molded at different expansion ratios, for example, two types of first expandable resin particles a1 on the low expansion side and second expandable resin particles a2 on the high expansion side. Since the expandable resin particles are used as the raw material, the filling port 18 is provided with supply means 21a, 21b from the supply hoppers 20a, 20b of the respective raw materials to the switching connection portion 22 and filling means such as a feeder (not shown). And is provided so that any one of the foamable resin particles a1 and a2 that are appropriately fed by air or the like can be selectively filled from the filling port 18 by switching the switching connecting portion 22. It has been. Reference numeral 19 denotes a recovery discharge pipe for discharging a surplus of the low-expanded foamed first foamable resin particles a1 filled in the entire cavity 25, and is connected to suction transfer means (not shown) such as a pump. The surplus foamable resin particles are appropriately discharged and collected by the operation of the suction transfer means.

  The filling port 18 and the recovery discharge pipe 19 are molded portions for molding other portions having a large volume other than the strength required portions, of the molded portions of the two types of foamable resin particles a1 and a2 of the container 50 to be molded. Although not shown, the opening in the mold surface on the cavity 25 side is provided so as to be openable and closable.

  On the other hand, the male mold 30 has a convex mold portion 31 and an opening end mold section 32 having a shape corresponding to the inner surface shape and the side wall upper end surface shape of the container 50 to be molded. Similar to the female mold 10, the mold part 32 has a large number of communication holes 33 penetrating from the interior space (chamber) 30 a to the molding surface, that is, the mold surface on the cavity 25 side, over almost the entire surface. ing.

  Further, the male mold 30 includes a steam supply pipe 34 and a drain pipe 35 that communicate with each other through open / close valves, and intake / exhaust means for sucking or exhausting air and steam when the raw material is charged or when heated steam is introduced. A pipe 36 is provided, and an exhaust valve 37 is provided separately from the pipe 36. Although illustration is omitted, an air supply pipe for releasing and a supply pipe for cooling water are also provided. As the intake / exhaust means, the pipe 36 may be omitted, and the drain pipe 35 may be branched in the middle of the piping to also serve as the intake / exhaust means. The intake / exhaust means can be omitted.

  The first moldable resin particles on the low-magnification-foamed side are formed in a predetermined molding portion corresponding to the strength required portion of the container 50 to be molded in the male mold 30, for example, the predetermined molding portion 38 for molding the corner vicinity region 54. A partial suction means for sucking and holding a1 in a predetermined portion corresponding to the corner vicinity region 54 in the cavity 25 through the communication hole 33 is different from the pipe 36 as the intake / exhaust means in other molding sites. It is provided so as to be capable of being sucked by a circuit. By this partial suction means, a flow of air flowing in from the filling port 18 is created so that the foamable resin particles a1 can be stably held in a predetermined portion in the cavity 25 in a block shape. preferable.

  As a partial suction means for the predetermined molding portion 38, a suction pipe 41 capable of suction is provided separately from the pipe 36 as the intake / exhaust means. Specifically, in the inner space 30 a of the male mold 30, a suction chamber 43 in which a region portion including the communication hole 33 of the predetermined molding portion 38 is separated from a region of another molding portion 39 by a partition wall 42. The suction chamber 43 is connected to a suction pipe 41 that constitutes a suction line in a separate circuit from the pipe 36 serving as an intake / exhaust means connected to the other interior space 30a. Suction can be performed only at the predetermined molding portion 38.

  The suction line by the suction pipe 41 is connected to a suction pump (a vacuum pump, a decompression pump, etc., not shown) that is driven and controlled separately from the suction / exhaust line of the pipe 36 serving as the suction / exhaust means. By connecting and controlling the opening and closing of the valves, each is set to perform a suction action as appropriate.

  Further, as shown in FIG. 3, when forming each corner vicinity region 54 of the four corners of the container 50 to be molded by low-magnification foaming, each predetermined molding portion 38 corresponding to each corner vicinity region 54 is controlled separately. A suction tube 41 is provided. Each suction tube 41 can be connected to a single suction pump and sucked with the same suction force. However, the female mold 10 and the male mold 30 are arranged side by side as shown in the figure. In many cases, in this case, the first foamed resin particles a1 on the low-magnification expanded side filled in the cavity 25 are lowered to the lower side and more particles are collected on the lower side. It is desirable to equalize the amount of expandable resin particles retained by suction.

  Further, the opening end mold portion 32 of the male mold 30 has a depth direction along the boundary portion in the cavity 25 at a location near the boundary portion with the predetermined molding portion 38 in the other molding portion 39, that is, An air blowing pipe 45 for blowing air in the height direction of the container side wall to be molded is provided. When the air blowing pipe 45 discharges the surplus of the first foamable resin particles a1 once filled in the cavity 25, the boundary portion separates from the air supply from the air supply pipe 47 for mold release. In order to blow out the foamable resin particles other than the predetermined portion corresponding to the corner vicinity region 54 in the cavity 25 so as to be surely discharged. The form (block-shaped aggregate form) and the amount of the foamable resin particles that are sucked and held at a predetermined portion in the cavity 25 can be made uniform (FIGS. 4 and 5).

  Although not shown in the figure, in the female mold 10, as in the male mold 30 described above, for example, a portion formed by a suction tube, a suction chamber, or the like is formed at a predetermined molding site for molding the corner vicinity region 54 as a strength required portion. The suction means is provided, and the suction / exhaust means provided in the female mold 10 can be configured to be sucked by a suction line separate from the pipe 16. In this case, the partial suction means of the male mold 30 can be implemented. The partial suction means can be provided only on the female mold 10.

  Next, the method of the present invention by a manufacturing apparatus having a molding die composed of the female die 10 and the male die 30 will be described based on the schematic diagrams of the respective steps in FIG. In this foam molding, two types of expandable resin particles a1 and a2 that can be molded mainly from the same resin and with different expansion ratios are used as raw materials.

  First, for example, the male mold 30 is moved in a direction opposite to the female mold 10 to close the mold. At this time, the drain pipe 15 of the female mold 10 is opened, and the pipe 36 as the intake / exhaust means of the male mold 30 and / or the pipe 16 as the intake / exhaust means of the female mold 10 is opened to release the internal air. (At this time, internal air is also released from both the male and female molds), and in the state where the mold closing is completed, the drain pipes 15 and 35 of the female mold 10 and the male mold 30 are closed [FIG. 6 (a)].

  Then, in the mold closed state, the female mold 10 and the male mold 30 are opened with the exhaust valves 17 and 37 and the male mold 30 is opened with at least the valve of the pipe 36 serving as the intake / exhaust means. The first foamable resin particles a1 on the low-magnification-foaming side that mold the corner vicinity region 54 are fed from the arranged filling port 18 by using air from the supply hopper 20a and filled into the entire cavity 25. At this time, as shown in FIG. 6B, the suction pipe 41 as the partial suction means of the predetermined molding portion 38 is sucked separately from the intake and exhaust action by the pipe 36 as the intake and exhaust means arranged in the male mold 30. The suction is performed at the predetermined molding portion 38 through the suction chamber 43 by operating.

  As described above, after the first expandable resin particles a1 are once filled in the entire cavity 25, the suction by the suction pipe 41 of the predetermined molding portion 38 is continued as shown in FIG. The pipes 16 and 36 of the mold 10 and the male mold 30 are closed. In this state, the valve of the release air supply pipe 47 of the male mold 30 (if necessary, the valve of the female mold release air supply pipe is also used. ) And air is blown from the inside of the male die 30 into the cavity 25 through the communication hole 33 other than the predetermined molding portion 38, and the recovery outlet 19 provided separately from the filling port 18. The surplus foamable resin particles a1 other than those sucked by the partial suction means (suction pipe 41) of the predetermined molding portion 38 in the cavity 25 are discharged by operating the air suction transfer means. . Thereby, it is possible to suck and hold a predetermined amount of the expandable resin particles a1 in the predetermined portions. In particular, when predetermined portions corresponding to a plurality of strength-required portions are set in the cavity 25, it is possible to reliably and substantially hold the same amount of expandable resin particles in each of the predetermined portions. .

  At this time, air is blown from the air blowing pipe 45 of another circuit provided in the opening end mold portion 32 of the male mold 30 along the boundary with the predetermined molding portion 38 in the other molding portion 39, and the cavity 25. The foamable resin particles a1 other than the predetermined portion corresponding to the inner corner vicinity region 54 are discharged so as to be blown away, and the foamable resin particles a1 are surely increased only in the predetermined portion and large in holding form and holding amount. It is preferable not to make a difference. At this time, a state in which the expandable resin particles a1 are gathered in a predetermined portion in the cavity 25 in a block shape by creating a flow of air flowing in from the filling port 18 by suction by the suction pipe 41 as the partial suction means. It can be held stably.

  Next, as shown in FIG. 6 (d), the suction valves 41 and 37 of the female mold 10 and the male mold 30 are opened while the suction by the suction pipe 41 of the predetermined molding portion 38 is continued, and the pipe is further used as the suction / exhaust means. 16 and 36 are opened, and the second expandable resin particles a2 on the high-expansion foamed side, which is a raw material for molding other portions other than the corner vicinity region 54, from the filling port 18 disposed in the female mold 10, The air is supplied from the supply hopper 20b using air, and the other part in the cavity 25, that is, the space part where the expandable resin particles a1 are not present is filled.

  In addition, when the filling of each of the first foamable resin particles a1 and the second foamable resin particles a2 is completed, the blown air provided in the pipe line of the filling port 18 with the opening end of the filling port 18 closed. It is assumed that the foaming resin particles a1 in the pipe line of the filling port 18 are excluded by operating the feeding means using the reverse direction.

  Thereafter, as shown in FIG. 6E, the exhaust valves 17 and 37 of the female mold 10 and the male mold 30 and the valves of the release air supply pipe 47 are closed, respectively, so that the female mold 10 and the male mold 30 are closed. Open one drain pipe 15 or 35, and if necessary, open a pipe 16 or 36 as an intake / exhaust means, thus opening the valve of the other steam supply pipe 34 or 14 of the female mold 10 and male mold 30. In one heating through steam, or by opening the drain pipes 15 and 35 of both the female mold 10 and the male mold 30 and the valves of the steam supply pipes 14 and 34, and heating and foaming through the heating steam from both sides. Perform molding. As a result, the first expandable resin particles a1 held in a predetermined portion in the cavity 25 corresponding to the corner vicinity region 54 of the container and the second expandable resin particles a2 filled in the other portions are integrated. To be molded.

  After this heat foaming, as shown in FIG. 6 (f), the release air is supplied from the release air supply pipe 47 with the steam supply pipes 14 and 34 closed and the drain pipes 15 and 35 opened. While blowing, either one, for example, the male mold 30 is moved to open the mold, and the foam molded product container is taken out.

  For example, the container 50 shown in FIG. 7 manufactured by heating and foaming has the first foamable resin particles a1 on the low-expanded foam side in which the entire thickness of the corner vicinity region 54 including the corner portion 53 that is a strength required portion is low. The expansion ratio is lower than that of the other part, and the other part is formed of the second expandable resin particle a2 on the high expansion side, so that the expansion ratio is higher than that in the corner vicinity region 54. In addition, the first expandable resin particles a1 are once filled into the cavity 25, and then the excess expandable resin particles a1 are discharged to suck and hold in predetermined portions in the cavity 25. Each of the predetermined portions can securely hold substantially the same amount of expandable resin particles in a block-like aggregated state, and the boundary between the corner vicinity region 54 as a plurality of strength-required portions and other portions is cleaned. Moreover, it can be molded with a good weight balance.

  In addition, although the expansion ratio of the foamed corner vicinity region 54 and the expansion ratio of other portions can be appropriately set according to the foamable resin particles a1 and a2 of the raw material used, for example, in the case of agricultural products containers and the like A difference of about 10 times is made, for example, the expansion ratio of the region 54 is 55 times and the expansion ratio of other portions is 65 times.

  In the above-described embodiment, the case where the container 50 including the bottom 51 and the four side walls 52 is manufactured has been described as an example. For example, the bottom 51, the side wall 52, and the opening end 50a have various irregular shapes. In the container of a form, it can carry out similarly to the above and can manufacture. In this case, the molding surfaces of the concave mold part 11 of the female mold 10 and the convex mold part 31 of the male mold 30 and the open end mold part 32 can be made to conform to the shapes of the inner and outer surfaces of the container and the open end part. That's fine.

  FIGS. 8-10 has shown one of the specific examples of the foamed resin container manufactured by the manufacturing method of this invention. This foamed resin container is formed from foamed resin particles such as foamed polystyrene, and is fitted and attached to a flat rectangular container body 50A that opens upward, and an opening end at the upper end of the side wall of the container body 50A. It consists of a free lid 60. The container main body 50 </ b> A is formed in a planar rectangular box shape by the bottom 51 and the four side walls 52.

  In the case of the figure, as the fitting and adhering structure of the lid body 30 to the container body 50A, the inner side of the opening end of the container body 50A, that is, the upper end of each side wall 52, leaving the fitting convex edge 55 on the outside. On the other hand, a fitting portion 62 that fits inside the convex edge 55 is formed on the lower surface of the peripheral edge portion 61 of the lid 60. Of course, the attachment structure by another fitting form may be sufficient.

  In the case of the container main body 50A shown in the figure, each side wall 52 is a concave in the vertical direction in which the inner surface of the central region 52a excluding the side wall side end portion in the vicinity of the corner portions 53 at the four corners is recessed with respect to the original inner wall surface. The strips 56 are formed at predetermined intervals in the circumferential direction of the container, thereby forming a corrugated shape with the concave strips 56 and the convex strips 57 remaining between the concave strips 56, 56, in the vertical direction. The ridges 57 have a reinforcing rib action with respect to a load from above such as a stacking load and a bending load inward and outward of the side wall 52, thereby maintaining the predetermined strength while maintaining the predetermined strength. Thinning by 56 is enabled.

  Further, at least one of the upper and lower surfaces of the bottom 51 of the container body 50A, for example, the upper surface 51a, is formed with a large number of planar hexagonal concave portions 59 defined by rib-shaped convex portions 58 having a predetermined height as shown in the figure. In order to contribute to the weight reduction of the container, the thickness of the concave portion 59 of the bottom portion 51 is made thinner than the original bottom portion while maintaining a predetermined strength by the rib-like convex portion 58. It has become. About the said honeycomb structure, it can also provide in the lower surface 51b of the bottom part 51, and can also provide in both the upper and lower surfaces 51a and 51b. Furthermore, another uneven | corrugated shape can also be provided in at least one of the upper and lower surfaces of the bottom part 51. FIG.

  And the container main body 50A of the said structure uses the at least 2 types of expandable resin particle a1, a2 which can be shape | molded by the above-mentioned manufacturing method of this invention by making an expansion ratio different, and similarly to the above, ( By performing heat foaming through the respective steps a) to (f), the entire thickness of the corner vicinity region 54 in the container main body 50A as the required strength portion in using the container is reduced to the first foam on the low-magnification foam side. It can shape | mold so that it may become a low expansion foam from other parts, such as the center part area | region 52a of the side wall 52, and the inner part of the bottom part 51 by the conductive resin particle a1. That is, it is possible to easily mold and manufacture the container main body 50A in which the entire thickness of the corner vicinity region 54 is foamed lower than the other portions. In the case of the figure, in addition to the corner portion 53, the corner vicinity region 54 including the side wall measuring portion excluding the central region 52a of the side wall 52 and the four corner regions of the bottom portion 51 is formed by lowering foaming than other portions. However, depending on the case, only the corner part 53 can be formed by foaming lower than the other parts.

  In addition to the container main body 50A, the lid 60 is also made of at least two types of expandable resin particles a1 and a2 that can be molded with different expansion ratios as in the case of the container main body 50A. By integrally heat-foaming through the steps (a) to (f), the corner portion 63 or the corner vicinity region 64 of the lid 60 corresponding to the corner portion 53 or the corner vicinity region 54 of the container body 50A can be changed. It can be manufactured by molding with a lower foam than the part.

  The foamed resin container formed of the container main body 50A and the lid body 60 formed and manufactured in this manner is the entire thickness of the corner vicinity region 54 including the corner portion 53 of the container main body 50A as described above, and further the lid. The entire thickness of the corner vicinity region 64 of the body 60 is formed by the first foamable resin particles a1 on the low-magnification foaming side and has a lower foaming ratio than the other parts. This is the waveform of the side wall 52 of the container body 50A. Combined with the uneven shape and the honeycomb structure of the bottom 51, the container as a whole can have compressive strength and tensile strength that can withstand a stacking load as compared with a conventional product having the same expansion ratio.

  Note that the strength required portion of the foamed resin container is not limited to the corner portion or the vicinity of the corner of the container, but also other strength required portions such as the opening end portion in the same manner as described above. It can be carried out by lowering foaming.

  Furthermore, although not shown in the drawings, when a plurality of strength-necessary portions having different magnifications are set in the foamed resin container to be manufactured, the above-described implementation is performed for each predetermined molding site for molding the strength-necessary portions having different magnifications. In the same manner as in the example, the foaming resin particles for molding each strength required portion are sequentially sucked and held in predetermined portions corresponding to the strength required portions in the cavity by the partial suction means of each strength required portion, and then the others. Part of the expandable resin particles can be filled and subjected to heat foaming. Also in this case, when the foamable resin particles used for each strength required part are sucked and held in a predetermined part, the entire cavity is once filled, and then the other part is filled while being sucked by the partial suction means of the predetermined molding part. The method can be carried out in the same manner as described above by using a method of discharging the surplus foamable resin particles that has been made, so as to be surely sucked and held at a predetermined portion in the cavity.

  Examples of the synthetic resin material of the expandable resin particles used for manufacturing the container 50, the container main body 50A, and the lid body 60 include styrene-modified polyolefin resin, polystyrene, high impact polystyrene, styrene-ethylene copolymer, styrene. -Various types of resins such as polystyrene resins such as maleic anhydride copolymer, styrene-acrylonitrile copolymer, polyolefin resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, or polyester resins such as polyethylene terephthalate. A thermoplastic synthetic resin material can be used. The expansion ratio is in the range of 10 to 70 times, and it is preferable to use the foam by making a difference of about 5 to 15 times between the low magnification foaming side and the high magnification foaming side.

  For example, foaming resin particles a1 on the low-magnification foaming side and foaming resin particles a2 on the high-magnification foaming side may be expanded in order to make a difference in the foaming ratio between the foamed resin particles of the same resin. Various implementations are possible in which the expansion ratio can be different, such as varying the particle size of the expandable resin particles, the type of foaming agent and the degree of pre-foaming, and the expandable resin particles a1 on the low-fold expansion side, A material of a different color can be used for the high-expansion foamed expandable resin particles a2, and a synthetic resin resin material of a different material can also be used if there is no problem in adhesiveness due to steam heating.

  a1 ... low-expandable foamed resin particles, a2 ... high-expandable foamable resin particles, 10 ... female mold, 11 ... concave part, 10a ... inside mold space, 13 ... communication hole, 14 ... steam supply pipe, DESCRIPTION OF SYMBOLS 15 ... Drain pipe | tube, 16 ... Pipe | tube as an intake-exhaust means, 17 ... Exhaust valve, 18 ... Filling port, 19 ... Collection | recovery discharge pipe, 20a, 20b ... Supply hopper, 21a, 21b ... Supply path, 25 ... Cavity, 30 ... male mold, 30a ... inside mold space, 31 convex mold part, 32 ... opening end mold part, 33 ... communication hole, 34 ... steam supply pipe, 35 ... drain pipe, 36 ... pipe as intake / exhaust means, 37 ... Exhaust valve, 38 ... predetermined molding site, 39 ... other molding site, 41 ... other suction pipe, 42 ... partition wall, 43 ... suction chamber, 45 ... air blowing pipe, 47 ... air supply pipe for mold release, 50 ... Container, 50A ... Container body, 51 ... Bottom, 11a ... Upper surface, 11b ... Bottom 52 ... Four side walls, 52a ... Central region, 53 ... Corner portion, 54 ... Corner vicinity region, 55 ... Convex edge, 56 ... Convex strip, 57 ... Convex strip, 58 ... Rib-shaped convex portion, 59 ... Concave portion, 60 ... Lid, 61 ... Peripheral part, 62 ... Fitting part, 63 ... Corner part, 64 ... Corner vicinity area.

Claims (13)

Filling the cavity of a molding die consisting of a male mold that molds the inner surface of the container and a female mold that molds the outer surface of the container, and foaming resin particles to make the parts that require strength lower than other parts. In the method for producing a foamed resin container to be molded,
At least one of the male mold and the female mold is provided with a large number of communication holes penetrating from the inside of the mold to the molding surface, and the foamable resin particles as a raw material are provided to the predetermined molding site for molding the required strength portion through the communication holes. A partial suction means for sucking and holding is provided,
At least two types of expandable resin particles that can be molded with different expansion ratios are used. In the filling step, first, the low-expansion expanded foam resin particles used for the strength-required portion are partially sucked at the predetermined molding site. By sucking and holding a predetermined portion corresponding to the required strength portion in the cavity by means, and then filling the other portion in the cavity with the foamed resin particles on the high expansion side used for the other portion, In this state, at least two kinds of expandable resin particles are filled, steam is blown in this state, and heat-foaming molding is performed, and a container having an overall wall thickness of the strength-required portion lower than that of the other portion is integrally molded. A method for producing a foamed resin container.   2. The foamed resin according to claim 1, wherein the low-expandable foamed resin particles are sucked and held in the predetermined portion in the front cavity, and then the foamed resin particles on the high-doubled foamed side are filled while maintaining the sucked and held state. A method for producing a container.   When the foamable resin particles on the low-magnification foam side are sucked and held in a predetermined portion in the cavity, the foamable resin particles are once filled in the entire cavity, and then sucked by the partial suction means at the predetermined molding site. 3. The method for producing a foamed resin container according to claim 1, wherein the predetermined portion is sucked and held by discharging excess foamable resin particles filled in the other portion while continuing.   When discharging surplus expandable resin particles filled in the other part in the cavity, a discharge port provided separately from the filling port or the filling port while blowing air into the cavity from the communication hole of another molding part The method for producing a foamed resin container according to claim 3, wherein the foamed resin container is sucked and discharged.   When discharging the surplus foamable resin particles filled in the other part in the cavity, air in a separate circuit is blown at the boundary between the predetermined part and the other part in the cavity so that the surplus foamable resin particles are blown off. The method for producing a foamed resin container according to claim 3 or 4, wherein the container is discharged as described above.   The strength required portion is a corner portion of a flat rectangular container, and the foamable resin particles on the low-magnification foam side are sucked and held in a predetermined portion corresponding to the container corner portion in the cavity, and then the foamable resin on the high-magnification foam side The method for producing a foamed resin container according to any one of claims 1 to 5, wherein the particles are filled so as to be sucked and held in a portion other than the portion corresponding to the corner portion in the cavity, and then heated and foam-molded. .   When multiple strength required parts with different magnifications are set in the foamed resin container to be manufactured, each strength is sequentially applied by each partial suction means for each predetermined molding part for molding the strength required parts with different magnifications. The foamed resin according to claim 1 or 2, wherein the foamable resin particles forming the necessary part are sucked and held in predetermined parts corresponding to the respective strength necessary parts in the cavity, and thereafter the foamable resin particles of the other part are sucked and held. A method for producing a container. Filling the cavity of a molding die consisting of a male mold that molds the inner surface of the container and a female mold that molds the outer surface of the container, and foaming resin particles to make the parts that require strength lower than other parts. In the manufacturing equipment for foamed resin containers to be molded,
Each of the male mold and the female mold has a large number of communication holes penetrating from the inner space of the mold to the molding surface, and at a predetermined molding site for molding at least one of the required strength portions, the foamable resin via the communication holes. A partial suction means for sucking and holding particles is provided in a separate circuit from the suction / exhaust means at other molding sites, and at least two of the male mold and the female mold can be molded with different expansion ratios. An apparatus for producing a foamed resin container, comprising a filling port for injecting and filling seed foamable resin particles into a cavity.   As a partial suction means for the predetermined molding portion of at least one of the male mold and the female die, a region including the communication hole of the predetermined molding portion in the inner space is formed as a suction chamber separated from the other portion by a partition wall. 9. The apparatus for manufacturing a foamed resin container according to claim 8, wherein a suction pipe constituting a suction line different from the suction / exhaust means of another molding site is connected to the suction chamber.   The apparatus for manufacturing a foamed resin container according to claim 8 or 9, wherein the male mold constituting the molding die is provided with partial suction means for the predetermined molding site.   By the manufacturing method according to any one of claims 1 to 7, at least two kinds of expandable resin particles that can be molded at different expansion ratios are filled in a cavity of a molding die and integrally heated and foamed. A foamed resin container, which is formed by foaming the entire thickness of a part requiring strength in use of the container with lower foaming than other parts.   The strength-required portion in the container is a corner vicinity region including a corner portion of the flat rectangular container body, and the corner vicinity region is integrally formed of a foamed resin having a lower magnification than other portions. The foamed resin container as described.   The foamed resin container according to claim 11, wherein a plurality of strength-required portions having different magnifications and lower magnification than other portions are set.

Images