JP6295440B2 - Mold for foamed resin moldings - Google Patents

Description

  The present invention relates to a mold for a foamed resin molded body, and more specifically, a portion that is difficult to be filled with thermoplastic resin beads (hereinafter sometimes simply referred to as resin beads) (hereinafter simply referred to as a difficultly filled portion). ) For example, resin beads can be efficiently and uniformly filled in a molding chamber of a mold for molding a molded body having a complicated shape having an engagement structure portion of a lid and a container body, and uniform heating・ Promoting cooling and shortening the molding cycle not only to improve production efficiency, but also to produce foamed resin molded products with uniform quality and excellent strength, especially foamed resin molded products with a uniform expansion ratio The present invention relates to a mold for foamed resin moldings.

  As a method for producing a foamed resin molded body made of foamed resin, resin beads formed by impregnating low-boiling hydrocarbons such as butane and pentane and foamed at a predetermined foaming ratio are used in a mold using compressed air. A so-called bead method is widely used in which a resin is softened by steam and a foaming agent such as a low-boiling hydrocarbon is thermally expanded after being introduced into a molding chamber, and the resin beads are fused together, cooled, and released. Yes.

Conventionally, when manufacturing a complex-shaped molded body having a difficult-to-fill portion that is difficult to be filled with resin beads by this bead method, for example, a molded body having a complicated shape having an engaging structure portion of a lid body and a container body, In a molding chamber composed of a core mold and a cavity mold, a narrow path with a core vent having a fine hole is formed in an engagement structure portion or the like. Resin beads accelerated and fluidized with a large amount of compressed air (for example, 5 kg / cm ² ) from a filling port (for example, a diameter of 22 mmφ × 2) provided in the base portion are successively filled in this narrow bag path (for example, 2 ~ 5 seconds) but without exhaust, near the filling port where the resin beads float and fluctuate due to the compressed air trapped without being exhausted in the bag path, and before the resin beads are sufficiently filled When the base portion or the standing wall portion is filled first, the filling port is closed, and the resin beads are blown back to complete the filling. As a result, since the process shifts to the molding process in a state where the resin bead is not sufficiently filled in the bag path, non-uniformity or reduction in the strength of the molded body due to non-uniform filling of the resin beads is an essential problem.

To solve this problem, the mold parting surface of the mold is opened to such an extent that the resin beads do not discharge, and cracking molding that exhausts intensively from the parting surface has become normal. A new problem arises of the essential problem of loss in filling and non-uniform filling.
In addition, in order to increase the displacement of the core vents, efforts have been made to increase the installation density of the core vents for a long time. Recently, molds with a pitch of 25 mm, which is the limit of the mold strength, have been standardized. The fact is that it depends on.

  For example, Patent Document 1 proposes a technique for improving the exhaust amount by intensively installing a core vent in a thin wall portion to increase the steam hole opening ratio.

JP 2003-62849 A

  As described above, Patent Document 1 discloses a method of filling thin-walled portions with resin beads by adjusting the number of installed steam holes to increase the vapor hole opening ratio at the front-end portion of the thin-walled portion. Has been.

  Therefore, the present inventors tried to increase the number of core vents installed in the thin portion ignoring the pressure resistance of the mold, but a sufficient effect of increasing the displacement was not recognized. Furthermore, as a result of research, the present inventors have a structure in which the current state of core vents such as thin-walled parts where exhaust performance is particularly required is a structure that must be installed crossing the filling direction of the filling air. Is combined with the refraction resistance caused by the exhaust structure that refracts at the core vent, the shunt resistance due to the micro vent of the core vent, and the ventilation resistance due to the micro flow, so that the displacement of the thin part is extremely low It was found that this is the cause of non-uniform filling.

  In addition, in order to solve the problems of cracking molding and core vent described above, new pressure filling method and compression filling method have been put into practical use, but these increase the amount of filling air because they are filled with resin beads at a stretch at high pressure. The fact is that the resin beads may float and fluctuate due to the absence of exhaust air, so it is actually used in combination with cracking molding.

  An object of the present invention is to improve one or more of the conventional problems, and by increasing the exhaust amount in the bag path portion, it is a difficult filling portion such as an engagement structure portion of the lid body and the container body. The resin beads are efficiently and uniformly filled into the molding chamber, and not only can the manufacturing efficiency be improved by promoting uniform heating / cooling and shortening the molding cycle, but also a foamed resin with uniform quality and excellent strength. It aims at providing the metal mold | die for foamed resin moldings which can shape | mold a molded object.

In order to solve the above problems, the foam molding die of the present invention has the following characteristics.
(1) A foamed resin molded body comprising a core mold and a cavity mold and including a hardly filled portion (hereinafter referred to as a difficultly filled portion) that is difficult to fill with resin beads in a molding chamber formed between the two molds is molded by a bead method. Is a mold for foamed resin moldings,
The difficult filling portion is either a square shape or an arc shape,
The mold is provided with at least one raw material filling port for introducing resin beads,
In the difficult filling portion, a linear opening is directly engraved on the molding chamber side by a cutting tool, and at least a part of the linear opening communicates with the steam chamber side,
The linear opening is embedded so as to wrap around three sides when the difficult-to-fill part is square, and is wrapped so as to wrap around the difficult-to-fill part when it is arcuate. The mold for foamed resin moldings.
(2) The mold for a foamed resin molded article according to (1) above, wherein the linear opening appearing on the surface of the molding chamber has a length of 20 mm or more and a width of 0.5 to 1.5 mm. It is.
(3) The foamed resin molded article according to any one of (1) and (2) above, wherein the opening ratio in the hardly filled portion is at least twice the opening ratio of the portion other than the hardly filled portion It is a mold.
(4) The foamed resin molded body mold according to any one of (1) to (3), wherein the linear opening has a slit shape communicating with the vapor chamber side.
(5) Both side walls of the linear opening portion are intermittently connected by the connecting portion,
The mold for a foamed resin molded article according to any one of the above (1) to (4), characterized in that the molding chamber side and / or the steam chamber side of the connecting portion converge.
(6) Both side walls of the linear opening are partially connected by a connecting portion;
The foamed resin as described in any one of (1) to (4) above, wherein a utility diffusion passage is provided in the linear opening and at least on the molding chamber side of the connecting portion. This is a mold for a molded body.
(7) The connection portion is provided inside the linear opening, and the utility diffusion passage is provided on both the molding chamber side and the steam chamber side of the linear opening. It is a metal mold | die for foamed resin moldings as described in 6).
(8) The foamed resin molded body mold according to (6), wherein the connecting portion is provided so as to protrude from the inside of the linear opening to the steam chamber side.
(9) The linear opening is a bottomed groove type provided on the molding chamber side, and a bottomed conduction hole is formed on the steam chamber side, and the linear opening and the conduction hole communicate with each other. The mold for a foamed resin molded article according to any one of the above (1) to (8), wherein the mold is used.
(10) The mold for a foamed resin molded body according to any one of (1) to (9) above, wherein the difficult filling part is a standing part, a narrow part, a bulging part, or a peripheral part. is there.
(11) The mold for a foamed resin molded body according to any one of (1) to (9), wherein the foamed resin molded body is a plate-shaped body, and the hardly filled portion is a peripheral portion. .
(12) In any one of the above (1) to (9), the foamed resin molded body is a container, and the difficult filling portion is an engaging portion with a lid erected at the end of the side wall. It is a metal mold | die for foamed resin moldings as described.
(13) Any of the above (1) to (9), wherein the foamed resin molded body is a lid, and the difficult filling portion is an engaging portion with a container erected on the peripheral edge of the lid It is a metal mold | die for foamed resin moldings.

According to the mold for a foamed resin molded body of the present invention (hereinafter sometimes simply referred to as a mold), a linear opening is formed on the molding chamber side of the difficult-to-fill part, and the linear opening By communicating at least a part of the portion to the steam chamber side, it is possible to remarkably reduce the airflow resistance of the hardly filled portion, and as a result, it is possible to increase the air permeation amount and increase the exhaust amount.
Preferably, the length of the linear opening is set to 10 mm or more, the width is set to 0.5 to 1.5 mm, and the opening ratio of the difficult filling part is set to the opening ratio of the part other than the difficult filling part. By setting it to 2 times or more, it is possible to reduce the ventilation resistance, increase the air permeation amount, and increase the exhaust amount.
By increasing the displacement, the compressed air used to introduce the resin beads is preferentially and smoothly discharged out of the mold from the edge, which is a difficult-to-fill part of the mold, and the resin beads are removed from the mold. Since it is not blown back before filling in the difficult filling portion, the resin beads are uniformly filled up to the edge of the difficult filling portion. In addition, since no turbulent flow is generated in the molding chamber, the resin beads are efficiently filled without floating or turbulent.
Thus, since the resin beads are uniformly filled from the base portion to the edge of the difficult-to-fill portion, material loss due to partial overfilling, uneven strength of the foamed resin molded body due to partial underfilling, The problem of insufficient strength is solved.

  The shape of the linear opening can be a slit shape. Further, if the shape of the opening is made such that the molding chamber side and / or the steam chamber side of the connecting portion converge, or if a service diffusion passage is provided on the molding chamber side of the connecting portion, the compressed air is more easily discharged. . As a result, the amount of compressed air exhausted is maximized in the difficult-to-fill part, so that the resin beads are efficiently and uniformly filled up to the tip of the difficult-to-fill part.

  Furthermore, the ridges formed in the difficult-to-fill parts of the foamed resin molded body reinforce the narrow parts such as the engagement parts that are likely to be cracked or chipped, and the ridges are formed in place of the conventional turtle shell pattern. A foamed resin molded product having a new design can be provided.

FIG. 1 is a schematic cross-sectional view showing a mold (container) according to Embodiment 1 of the present invention. FIG. 2 is a schematic sectional view clearly showing a molding chamber in the mold of FIG. FIG. 3 is a schematic sectional view showing a core mold in the mold of FIG. FIG. 4 is a schematic cross-sectional view showing a cavity mold in the mold of FIG. FIG. 5 is a schematic cross-sectional view showing a mold (lid body) according to Embodiment 2 of the present invention. FIG. 6 is a schematic sectional view clearly showing a molding chamber in the mold of FIG. FIG. 7 is a schematic cross-sectional view showing a core mold in the mold of FIG. FIG. 8 is a schematic sectional view showing a cavity mold in the mold of FIG. 9A is an enlarged cross-sectional view of the main part of the mold of FIG. 5, FIG. 9B is a schematic view of the edge of the core mold as viewed from the molding chamber side, and FIG. 9C is a cross-sectional view of the edge of the core mold. d) is a schematic view of the edge of the core mold as viewed from the steam chamber side. FIG. 10A is a schematic view of a corner portion of the lid body created using the mold of FIG. 9, and FIG. 11 (a) is an enlarged cross-sectional view of the main part in another example of the lid mold, (b) is a schematic view of the edge of the core mold as viewed from the molding chamber side, and (c) is a cross-section of the edge of the core mold. FIG. 4D is a schematic view of the edge of the core mold as viewed from the steam chamber side. FIG. 12A is a schematic view of a corner portion of a lid body created using the mold of FIG. 11, and FIG. 13A is an enlarged cross-sectional view of a main part in still another example of the lid mold, FIG. 13B is a schematic view of the edge of the core mold as viewed from the molding chamber side, and FIG. 13C is the edge of the core mold. Sectional drawing, (d) is a schematic view of the edge of the core mold as seen from the steam chamber side. FIG. 14A is a schematic view of a corner portion of the lid body created using the mold shown in FIG. 13, and FIG. FIG. 15A is a schematic view of a corner portion in another example of the lid, and FIG. FIG. 16A is a schematic view of a corner portion in another example of the lid, and FIG. FIG. 17A is a schematic view of a corner portion in another example of the lid body, and FIG. 18A is an enlarged cross-sectional view of the main part in still another example of the lid mold, FIG. 18B is a schematic view of the edge of the core mold as viewed from the molding chamber side, and FIG. 18C is the edge of the core mold. Sectional drawing, (d) is a schematic view of the edge of the core mold as seen from the steam chamber side. 19A to 19C are cross-sectional views of a linear opening communicating with the steam chamber side. 20A to 20D are cross-sectional views of linear openings in which both side walls are intermittently connected by a connecting portion. FIGS. 21A to 21C are cross-sectional views of a linear opening in which both side walls are partially connected by a connecting portion. FIG. 22 is a plan view showing an example of a plate-like foamed resin molded body molded by the mold of the present invention. FIGS. 23A to 23C are cross-sectional views of the main part of the plate-like foamed resin molded body of FIG.

  The foamed resin molded body mold of the present invention comprises a core mold and a cavity mold, and a foamed resin molded body including a difficult-to-fill part that is difficult to fill with resin beads in a molding chamber formed between both molds is molded by a bead method. A mold for a foamed resin molded body, wherein the mold is provided with at least one raw material filling port for introducing resin beads, and a linear opening is formed on the molding chamber side in the difficult filling portion. It is engraved and at least a part of the linear opening communicates with the steam chamber side.

In the present invention, the “metal mold” may refer to either a core mold or a cavity mold, or both a core mold and a cavity mold. In addition, the “mold base portion” should be accurately expressed as “the portion of the mold for forming the base portion of the molded body”, but in order to avoid complication, simply “the mold base portion”. Part ". Further, the “base portion of the mold” may be referred to as “mold of the base portion”. The same applies to names that originally indicate parts of the molded body, such as difficult-to-fill parts, standing parts, narrow parts (including thin parts), bulged parts, and bent parts.
The “difficult filling part” refers to a part that is difficult to be filled with resin beads, such as an engaging structure part of the lid and the container main body, a standing part extending from the base part, a narrow part, a bulging part, and the like. . Specifically, side walls or partitions that stand substantially vertically from the bottom of the container, L or the like that engage with the side walls of the container, or fitting parts, cushioning materials, structural members, etc. that stand substantially vertically from the lid of the container. A protruding bent portion or the like at an arbitrary angle such as a letter shape or a concave shape is included.
Further, in the case of a plate-like foamed resin molded body, the peripheral portion of the plate-like body is included in the difficult-to-fill portion because it is less likely to be filled with resin beads than the inner base portion. In particular, when the thickness of the plate-like portion is relatively small, for example, 200 mm or less, further 150 mm or less, particularly 100 mm or less, the thickness from the edge of the plate-like portion to the base portion side is about 1 to about 1 times. The portion up to 1.5 times is difficult to be filled with resin beads, and is included in the difficult filling portion.
The “standing portion” refers to a protruding portion or a bent portion formed at an arbitrary angle such as a T shape, an L shape, or a U shape with respect to the base portion of the foamed resin molded body.
The “narrow portion” refers to a portion formed with a thickness of at least 2/3 or less of the thickness of the base portion of the foamed resin molded body, and the same applies to a thin portion.
The “bulged portion” refers to a portion formed with a thickness of at least 1.3 times the thickness of the base portion of the foamed resin molded body.
"Utilities" and refers to steam or compressed air or water-cooling is used in the manufacture of foamed resin molded body, air cooling (cooling), the air and water during vacuum suction or evacuation.

Hereinafter, the foamed resin molded body has a bottom portion that is a base portion, a side wall standing around the bottom portion, and an engagement portion with a lid that is a difficult-to-fill portion provided at an edge portion of the side wall. The container will be described as an example.
1 to 4 show a first embodiment of a mold according to the present invention, which is composed of a core mold 1A and a cavity mold 1B, and includes a base part (bottom part) 3 and a side wall 4 standing around the base part 3. Is a metal mold for molding a foamed resin molded body (container) by the bead method, and at least one raw material filling port 3a for introducing the resin beads is provided in the base portion 3 of the mold (cavity mold 1B). In addition, the molding chamber 5 formed between the core mold 1A and the cavity mold 1B has a raw material filling port 3a (strictly speaking, a discharge port of a raw material filling device installed in the hole 3a) of the mold base 3 ) Is introduced to the edge 4a of the side wall 4, and the linear opening 2a is formed in the mold 1 at the edge 4a of the side wall 4 and the engaging part 4b. It is engraved. Further, at least a part of the linear opening 2a communicates with the steam chamber 6 side.
In FIG. 1 to FIG. 4, the end edge portion 4a is provided with an engaging portion 4b, which is a thin, narrow portion, fitted inside the end edge portion 4a so as to be fitted with the engaging portion of the lid. Yes. Further, a core vent C is disposed in a portion other than the end edge portion 4a and the engaging portion 4b, which are the difficult filling portions, thereby suppressing the amount of utility discharged in a portion other than the difficult filling portion. Therefore, it is considered that the amount of utility discharged in the difficult filling portion is increased. In addition, in the difficult filling part, it is also possible to adjust the discharge amount of utility by using the linear opening 2a and other core vents or the like as needed.

The present invention is a mold 1 comprising, for example, a core mold 1A as shown in FIG. 3 and a cavity mold 1B as shown in FIG. 4, for example. These core mold 1A and cavity mold 1B are shown in FIG. By combining them as described above, the molding chamber 5 is formed between the core mold 1A and the cavity mold 1B. FIG. 2 shows the formed molding chamber 5 by shading.
The mold 1 (cavity mold 1B) is provided with a raw material filling port 3a for introducing resin beads together with a large amount of compressed air into the molding chamber 5. Although not shown, the raw material filling port 3a is connected to a discharge port of a raw material filler, and resin beads are filled into the molding chamber 5 from this discharge port. In addition, although the installation place of the raw material filling port 3a is not specifically limited, in this example, it is provided in the base | substrate part 3 of the cavity type | mold 1B. When the side wall 4 is erected around the base portion (bottom portion) 3 as in the illustrated container, this is difficult for the end edge portion 4a of the side wall 4 and the engaging portion 4b which is a thin narrow portion. This is a preferred mode for efficiently filling the resin beads into the filling portion.
In addition, since the side wall 4 is also erected from the base body portion 3, it is a harder filling portion than the base body portion 3, and a linear opening 2 a can also be arranged on the side wall 4 as necessary. In this case, it is preferable to arrange the linear opening 2a so that the exhaust amount becomes larger toward the edge 4a of the side wall 4.
Further, at least one raw material filling port 3a is provided. If there are too many raw material filling ports 3a, the number of raw material fillers increases, which not only increases the cost, but the amount of compressed air supplied may exceed the amount of exhaust from the mold, and instead compressed air is discharged. Without being blown back, the filling property of the resin beads may be lowered.
Therefore, it is preferable to determine the number of raw material filling ports 3a (that is, raw material filling devices) in consideration of the displacement of the mold in addition to the shape and size of the molded body.

In the mold 1 of the present invention, a linear opening 2a for introducing or discharging a utility is provided. The linear opening 2a may be linear or curved. This linear opening 2a is preferably directly cut into the mold 1 by using an appropriate cutting tool such as an end mill. For example, in the case of a core vent, a hole is made in the mold in advance, and the core vent is fitted into the hole and brazed, but this is not only labor-intensive, but also generates a connection portion between the core vent and the mold. However, when the linear opening is engraved immediately after the linear opening as described above, there is an advantage that such a problem does not occur.
The linear opening 2a is provided in the core mold 1A, the cavity mold 1B, or both molds 1A, 1B. It is preferable that the linear opening 2a is wrapped around a difficult-to-fill part such as the edge part 4a or the engaging part 4b. In the case of wrapping, it is provided so as to wrap three sides when the difficult-to-fill portion is square, and to wrap it when it is arcuate . By being Tsutsumi設so as to enclose the flame filling portion as this, the amount of exhaust gas increases, uniform filling of the filling bead of the flame filling portion is effectively achieved.
The length of the linear opening 2a is not particularly limited, but is preferably longer, specifically 10 mm or more, preferably 20 mm or more, and more preferably 30 mm or more. The upper limit is not particularly limited and is appropriately determined in consideration of the strength of the mold.
The width of the linear opening 2a is such that at least the diameter of the resin beads filled in the molding chamber 5 is prevented so that the resin beads are not discharged together with the compressed air from the molding chamber 5 when the compressed air is discharged. Need to be narrower. Specifically, since the diameter of the pre-foamed resin beads is usually about 2 to 6 mm, when such resin beads are used, the width W of the linear opening 2a is made smaller than about 1.5 mm. Is preferred.
Further, the width of the linear opening 2a is preferably 0.2 mm or more so that the utility can be introduced into the mold or discharged from the mold, but the utility can be introduced or discharged more smoothly. Therefore, 0.5 mm or more is more preferable, and 0.8 mm or more is more preferable.
The specific shape of the linear opening 2a is not particularly limited, and may be a slit shape penetrating from the inlet to the outlet, or provided with a bottomed groove on the molding chamber side, and on the steam chamber side. It may have a structure in which a bottomed conduction hole is provided and the bottomed groove and the conduction hole communicate with each other. Details of these will be described later in the description of the lid.

In order to sufficiently achieve the object of the present invention to increase the discharge amount of the end edge portion 4a and the engagement portion 4b from the difficult filling portion, the discharge amount from portions other than the difficult filling portion is relatively suppressed. Is desirable. For example, if a conventional exhaust means such as a core vent or a drill hole is used at a portion that relatively suppresses these discharge amounts, the discharge air is refracted at the core vent or the drill hole portion as described above. Because the refraction resistance caused by the flow, the shunt resistance due to the fine holes in the core vent, and the airflow resistance due to the microflow are combined, the airflow resistance increases, so even if the aperture ratio is the same, difficult filling The amount of discharge from the department increases. Further, even when the linear opening 2a is provided in a portion other than the difficult filling portion, if the width is narrower and the length is shorter than the linear opening 2a provided in the difficult filling portion, the opening may be similar to the above. Even if the rate is the same, the ventilation resistance becomes relatively large, so that the discharge amount from the difficult filling portion becomes large.
However, from the viewpoint of increasing the discharge amount of the end edge portion 4a and the engaging portion 4b from the hardly filled portion, the opening ratio at the end edge portion 4a and the engaging portion 4b of the hardly filled portion is a portion other than the hardly filled portion. It is preferable that the opening ratio is 2 times or more, more preferably 3 times or more, particularly 5 times or more. The upper limit of the aperture ratio is determined in consideration of the strength of the mold.
A molded body (container X) created using the above-described mold is a molded body having a shape as in the molding chamber 5 shown in FIG.

Next, a detailed description will be given by taking, as an example, a lid body in which a foamed resin molded body includes a central portion that is the base portion 3 and an engagement portion that is provided around the central portion and that is a difficult-to-fill portion and is engaged with the container body. Explained.
FIG. 5 to FIG. 8 show Embodiment 2 of the mold of the present invention, which comprises a core mold 1A and a cavity mold 1B, and a base portion (center portion) 3 and a hardly filled portion provided around the base portion 3. This is a mold for molding a foamed resin molded body (lid body) composed of the end edge part 4a and the engaging part 4b by the bead method, and the raw material filling port 3a for introducing the resin beads is a mold (cavity mold). 1B) is provided in at least one base portion 3 and a molding chamber 5 formed between the core die 1A and the cavity die 1B has a material filling port 3a (strictly speaking, the hole) of the base portion 3 of the mold. The resin beads introduced from the discharge port of the raw material filler installed in 3a) are guided to the edge part 4a and the engaging part 4b of the difficult filling part, and the edge part 4a of the difficult filling part The engagement portion 4b has a linear opening 2a formed in the mold 1. Further, at least a part of the linear opening 2a communicates with the steam chamber 6 side.
5 to 8, the end edge portion 4a is provided with an engaging portion 4b for engaging with an engaging portion 4b erected on the end edge portion 4a of the container body. Further, a core vent C is disposed in a portion other than the difficult filling portion, thereby suppressing the discharge amount of utility in the portion other than the difficult filling portion, and as a result, the discharge amount in the difficult filling portion is large. Is considered to be.

The present invention is a mold 1 comprising, for example, a core mold 1A as shown in FIG. 7 and a cavity mold 1B as shown in FIG. 8, for example. These core mold 1A and cavity mold 1B are shown in FIG. By combining them as described above, the molding chamber 5 is formed between the core mold 1A and the cavity mold 1B. FIG. 6 shows the formed molding chamber 5 by shading.
The mold 1 (cavity mold 1B) is provided with a raw material filling port 3a for introducing resin beads together with a large amount of compressed air into the molding chamber 5. Although not shown, the raw material filling port 3a is connected to a discharge port of a raw material filler, and resin beads are filled into the molding chamber 5 from this discharge port. In addition, although the installation place of the raw material filling port 3a is not specifically limited, in this example, it is provided in the center part of the base | substrate part 3 of the cavity type | mold 1B.

A linear opening 2 a is directly engraved in the mold 1 at the edge 4 a and the engaging portion 4 b of the difficult filling portion. The advantages of directly engraving the linear opening 2a in the mold 1 are as described above. The advantage of wrapping the linear opening 2a so as to wrap the difficult-to-fill part is also as described above.
The specific shape of the linear opening 2a is not particularly limited, and may be a slit shape penetrating from the inlet to the outlet, or provided with a bottomed groove on the molding chamber side, and on the steam chamber side. It may have a structure in which a bottomed conduction hole is provided and the bottomed groove and the conduction hole communicate with each other.
FIGS. 9A to 9D are enlarged cross-sectional views of the main part of the mold, and FIG. 9A is an enlarged cross-sectional view of the main part cut by the linear opening 2a of the mold. ), A linear opening 2a is provided when viewed from the molding chamber 5 side. As shown in FIG. 9C, the linear opening 2a has a slit shape and communicates with the vapor chamber side. doing. That is, as shown in FIG. 9D, the opening 2a has a slit shape when viewed from the vapor chamber 6 side.
When such a mold is used, as shown in FIG. 9A, the utility is introduced together with the resin beads R from the base portion 3 to the end edge portion 4a and the engaging portion 4b which are difficult to fill, and the wire Resin beads R are left at the inlet of the opening 2a to fill the end edge 4a and the engaging portion 4b, and only the utility enters the linear opening 2a and is discharged to the vapor chamber 6 side.
Part of a molded body (lid Y) created using such a mold 1 is shown in FIGS. Note that FIG. 10A is described assuming that the molded body is transparent in order to show the shape and structure of the back side of the molded body. The same applies to FIG. 12A, FIG. 14A, FIG. 15A, FIG. 16A, and FIG.
FIG. 10 (a) is a schematic view showing the corners of the formed body, but as shown in FIG. 10 (b), the ridges 8 derived from the linear openings 2a are formed on the surface of the formed body. Formed.

11 (a) to 11 (d) are enlarged sectional views of other main parts of the mold. A bottomed groove 2b is provided on the molding chamber 5 side, and a bottomed conduction hole 2c is provided on the steam chamber 6 side. The bottomed groove 2c and the conduction hole 2b are communicated with each other so as to form a linear opening 2a.
As shown in FIG. 11 (b), a bottomed groove 2b is provided when viewed from the molding chamber 5 side, and a conduction hole 2c is provided on the steam chamber 6 side as shown in FIG. 11 (d). ing. The bottomed groove 2b and the conduction hole 2c communicate with each other to form a linear opening 2a as shown in FIG.
When such a mold is used, as shown in FIG. 11 (a), the utility is introduced together with the resin beads R from the base portion 3 to the end edge portion 4a and the engaging portion 4b which are hard-to-fill portions. Resin beads R are left at the entrance of the cylindrical opening 2a (bottomed groove 2b and conduction hole 2c) to fill the edge 4a and the engaging part 4b, and only the utility is applied to the linear opening 2a. It enters and is discharged to the steam chamber 6 side.
A part of the molded body (lid Y) created using such a mold 1 is shown in FIGS. FIG. 12 (a) is an explanatory view showing the corners of the formed body, but as shown in FIG. 12 (b), the protrusions derived from the linear openings 2a (bottomed grooves 2b). A strip 8 is formed on the surface of the molded body.

Further, a bottomed groove may be formed in at least one of the core mold 1A and the cavity mold 1B so as to form a slit shape only after the core mold 1A and the cavity mold 1B are combined. Such an example is shown in FIGS.
In this example, as shown in FIGS. 13B to 13D, when viewed from the molding chamber 5 side, a notch that is open on the outside (right side in the figure) is provided, and when combined with the cavity mold 1B, It is comprised so that it may become the linear opening part 2a.
When such a mold is used, as shown in FIG. 13A, the utility is introduced together with the resin beads R from the base portion 3 to the end edge portion 4a and the engaging portion 4b which are difficult to fill portions, Resin beads R are left at the inlet of the opening 2a to fill the end edge 4a and the engaging portion 4b, and only the utility enters the linear opening 2a and is discharged to the vapor chamber 6 side.
FIGS. 14A and 14B show a part of a molded body (lid Y) created using such a mold 1. FIG. 14 (a) is a schematic view showing the corners of the formed body, but as shown in FIG. 14 (b), the ridges 8 derived from the linear openings 2a are formed on the surface of the formed body. Formed.

FIGS. 15 to 17 are schematic views showing corner portions of the molded body, although the illustration of the mold is omitted.
FIG. 15 is an example in which a linear opening 2a is provided in the entire core-type hard-filling portion (end edge portion, engaging portion), and the obtained molded body (lid Y) has a hard-filling portion. The ridges 8 are formed on the entire surface in contact with the core mold.
FIG. 16 shows an example in which a linear opening 2a is provided in the entire cavity-type difficult filling portion (end edge portion, engaging portion). The obtained molded body (lid Y) has a difficult filling portion. The ridges 8 are formed on the entire surface in contact with the cavity mold.
FIG. 17 shows an example in which a linear opening 2a is provided in the whole of the hard filling portion (end edge portion, engaging portion) of the core mold and the cavity mold, and it is difficult to obtain the molded body (lid Y). The ridges 8 are formed on the entire surface of the filling portion in contact with the core mold and the cavity mold.

In the present invention, the linear opening 2a can be formed in a slit shape, and a hole that enlarges a part of the slit from the vapor chamber 6 side can be provided.
Examples of such molds are shown in FIGS. In this example, a conduction hole 2c is formed on the steam chamber 6 side of the notch similar to that shown in FIG. 13, and the air permeability (dischargeability) is improved compared to the mold shown in FIG. ing.

  When making the linear opening 2a of the present invention into a slit shape penetrating from the inlet to the outlet, as shown in FIG. 19 (a), the whole of the linear opening 2a from the inlet to the outlet is the same size. The vapor chamber 6 may be communicated with the side, but this is not always necessary. For example, as shown in FIGS. 19B and 19C, one end side or both ends of the linear opening 2a are bottomed. It can also be groove-shaped. Thus, if a part of the linear opening 2a has a bottomed groove shape, the exhaust performance can be improved and the strength of the mold can be maintained.

When the linear opening 2a has a slit shape, the connecting portion plays a role of reinforcement by connecting both side walls of the slit intermittently (see FIG. 20) or partially (see FIG. 21). The strength of the mold 1 can be increased while ensuring the exhaustability at the end edge portion 4a and the engaging portion 4b of the filling portion.
The method for forming the connecting portion 2d is not particularly limited. For example, a method of forming the connecting portion 2d in a plate-shaped mold material using an appropriate cutting tool such as an end mill can be used.

The connecting portion 2d is not particularly limited except that the molds on both sides of the linear opening 2a are intermittently and integrally connected, and the shape and arrangement of the connecting portion 2d can be determined as appropriate. However, from the viewpoint of introduction / discharge of utility, it is preferable that the molding chamber side 5 and / or the steam chamber 6 have a converging shape.
For example, FIG. 20A is a diamond shape, FIG. 20B is a pentagon shape, FIG. 20C is a hexagon shape, and FIG. 20D is a circle shape. -Since the portion (dead area) that hinders the discharge is substantially removed, the utility can be introduced and discharged efficiently.

FIG. 21A shows a pentagonal shape in which the connecting portion 2d is provided on the steam chamber 6 side and corners near the top on the molding chamber 5 side are removed, and the linear opening 2a is used on the molding chamber 5 side. This is an example in which a diffusion passage 2e is formed. In FIG. 21B, the connecting portion 2d is provided inside the linear opening 2a (substantially the center in the drawing), and the utility diffusion is performed on both the molding chamber 5 side and the steam chamber 6 side of the connecting portion 2d. This is an example of a hexagonal shape in which a passage 2e is formed. In these cases, the utility is efficiently discharged.
Furthermore, FIG.21 (c) is the example which provided the connection part 2d protruded in the vapor | steam chamber 6 side from the inside of the linear opening part 2a. In this case, the surface area on the steam chamber 6 side is increased, and the heating and cooling efficiency is enhanced. Further, in the case where the connecting portion 2d is provided so as to protrude toward the steam chamber 6 by the thinning, in addition to the effects of the heating and cooling efficiency, the weight of the mold can be reduced.
The connecting portions 2d having different shapes and arrangements are used in combination as necessary.

As described above, since the mold of the present invention is provided with the linear opening 2a that opens on the surface of the molding chamber 5, the resin beads are introduced into the molding chamber 5 using compressed air. Even when the compressed air is sufficiently discharged from the linear opening 2a and cracking is not performed (non-cracking), the resin beads are uniformly filled in the mold. Accordingly, there is no loss of material due to non-uniform filling of resin beads or a decrease in strength of the foamed resin molded body.
Moreover, when molding using the mold of the present invention, cracking can be performed as necessary. Even in that case, since the cracking width may be narrow, problems such as a loss of excessive filling of the resin beads, non-uniform filling, non-uniform strength of the foamed resin molding, and non-uniform dimensional accuracy are improved.

The present invention is also applied to a plate-like foamed resin molding. That is, in the case of a plate-like foamed resin molded body, the peripheral portion is included in the difficult filling portion because it is less likely to be filled with resin beads than the central portion. In particular, when the thickness of the plate-like portion is relatively small, for example, 200 mm or less, further 150 mm or less, particularly 100 mm or less, the thickness from the edge of the plate-like portion to the base portion side is about 1 to about 1 times. The portion up to 1.5 times is difficult to fill because the resin beads are difficult to fill. According to the present invention, even if the plate-like foamed resin molded body has a complicated and complicated shape as shown in FIG. 22, the resin beads can be filled to every corner.
When molding a plate-like foamed resin molded product with the mold of the present invention, the mold of the present invention has excellent compressed air discharge and excellent resin bead filling, and therefore can be molded without cracking. In addition, since the number of raw material fillers can be reduced, there is an advantage that the cost can be reduced. In particular, a large plate-shaped foamed resin molded body that is difficult to fill with resin beads to the end, preferably a plate-shaped foamed resin molded body with one side or diameter of 300 mm or more, more preferably one side or diameter of 500 mm or more. Useful.
In the case of molding by non-cracking, at least one side, preferably two sides, more preferably three sides of the U-shaped plate-like part (peripheral part) defined by the core mold and the cavity mold are the present invention. A mold provided with a linear opening is desirable.
That is, as shown in FIG. 23, the peripheral portion of the foamed resin molded body is formed by providing the linear opening 2a in the mold as shown in (a), (b), and (c). It can be set as the foaming resin molding by which the protruding item | line part 8 derived from the shape-shaped opening part 2a was formed in the peripheral surface.
As described above, when the container and the lid body are molded by the mold of the present invention, the protruding portion derived from the linear opening is formed in each engaging portion, but this protruding portion is cracked. In addition to reinforcing the engagement portion that is likely to be chipped, it plays the role of a cushioning material that tightly contacts the lid and the container, and has an effect of preventing the lid from being carelessly detached from the container. Moreover, the container and lid | cover which have a new design in which the protruding item | line part was formed instead of the conventional turtle shell pattern can be provided.

  There is no restriction | limiting in the resin bead used in this invention, A thermoplastic resin, biodegradable plastic, biomass plastic etc. are mentioned.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Examples 1 and 2 and Comparative Example 1
A total of 6 types of lids were created using 3 types of molds and 2 types of filling conditions.
The dimensions of the created lid are 320 mm long, 580 mm wide, 35 mm high, and the volume of the molded product is 3800 ml. Six such molds were provided in a molding machine ACE30 manufactured by Sekisui Koki Co., Ltd. for molding. The raw material resin beads are expanded polystyrene beads (pre-expanded magnification of 68 times).

In Example 1, as shown in FIG. 15, a linear opening is provided in the entire core-type hard filling portion (end edge portion, engaging portion), and the opening ratio is 5% in the hard filling portion. A die having a linear opening with a width of 0.5 mm was provided so that the core vent was provided so that the opening ratio was 3% at other locations.
In Example 2, a mold produced in the same manner as in Example 1 was used except that the opening ratio was adjusted to 10% in the difficult-to-fill part.
Comparative Example 1 is a conventional mold formed so as to exhaust through the core vent at the difficultly filled portion and other portions, and the opening ratio is adjusted to 5% in the difficultly filled portion and 3% in the other portions. Was used.

There are two types of filling of the raw material resin beads: non-cracking filling and 3 mm cracking filling.
Non-cracking filling is a method in which the resin beads as raw materials are put in a state where the core mold and the cavity mold are aligned with no gap. After filling, the core mold and the cavity mold are formed without moving.
The 3 mm cracking filling is a method in which raw material resin beads are introduced in a state where the core mold and the cavity mold are opened by 3 mm in the vertical direction. In this state, a gap of 0.8 mm is formed between the core mold and the cavity mold, and compressed air is exhausted from here. When resin beads are filled by this method, it is necessary to clamp the mold after filling to match the core mold and the cavity mold with no gap and to mold in this state.

Table 1 shows the results of measuring the uniformity of the filled resin with respect to the lid prepared under the above filling conditions. Regarding the uniformity of the resin, the expansion ratio was measured for the difficultly filled portion and the other portions, and evaluated by the following criteria based on the difference in expansion ratio. Further, the degree of fusion of the hardly filled portion was visually evaluated according to the following criteria.
(Foaming ratio)
×: Impossible to mold Δ: Difference in foaming ratio is 5 or less and exceeds 2 ○: Difference in foaming ratio is 2 or less and exceeds 0.5 ◎: Difference in foaming ratio is 0.5 or less (degree of fusion)
×: Molding not possible Δ: Slightly poor ○: Good ◎: Very good

From Table 1 above, in the case of the conventional mold using the core vent of Comparative Example 1, it is impossible to mold by non-cracking filling, and a molded body can be obtained by cracking filling. It is hard to say that it is satisfactory enough.
On the other hand, in the case of the mold of the present invention using the linear openings of Examples 1 and 2, the resin uniformity and fusing properties are sufficiently satisfied in both non-cracking filling and cracking filling. A good foamed molded product to be obtained is obtained.

As described above, the metal mold of the present invention has a small opening resistance due to a special opening structure using a linear opening, and a large amount of exhaust in the difficult-to-fill part, resulting in the introduction of resin beads. The compressed air used in the process is preferentially and smoothly discharged out of the mold from the edge.
As a result, conventionally, since the resin beads are blown back before being filled into the hard filling portion of the mold, the resin beads are filled from the vicinity of the raw material filling port of the base portion rather than the hard filling portion. While it is not uniformly filled, the mold of the present invention is filled preferentially from the front end of the difficult-to-fill part and finally fills the vicinity of the raw material filling port. Is uniformly filled. In addition, since no turbulent flow is generated in the molding chamber, the resin beads are efficiently filled without floating or turbulent.
Thus, since the resin beads are uniformly filled from the base portion to the edge of the difficult-to-fill portion, material loss due to partial overfilling, uneven strength of the foamed resin molded body due to partial underfilling, Problems with conventional technology such as insufficient strength are solved at once.

DESCRIPTION OF SYMBOLS 1 Mold for foamed resin molding 1A Core type 1B Cavity type 2a Linear opening 2b Bottomed groove 2c Conduction hole 2d Connection part 2e Useful diffusion passage 3 Base part 3a Raw material filling port 4 Side wall 4a Edge 4b Engagement section 5 Molding chamber 6 Steam chamber 8 Convex section C Core vent R Resin beads X Container Y Lid

Claims (13)

For forming a foamed resin molded body comprising a core mold and a cavity mold and including a hardly filled portion (hereinafter referred to as a difficultly filled portion) in which a resin bead is difficult to fill in a molding chamber formed between both molds by a bead method. It is a mold for foamed resin moldings,
The difficult filling portion is either a square shape or an arc shape,
The mold is provided with at least one raw material filling port for introducing resin beads,
In the difficult filling portion, a linear opening is directly engraved on the molding chamber side by a cutting tool, and at least a part of the linear opening communicates with the steam chamber side,
The linear opening is embedded so as to wrap around three sides when the difficult-to-fill part is square, and is wrapped so as to wrap around the difficult-to-fill part when it is arcuate. Mold for foamed resin moldings.   2. The mold for a foamed resin molded article according to claim 1, wherein the linear opening appearing on the surface of the molding chamber has a length of 10 mm or more and a width of 0.5 to 1.5 mm.   The mold for a foamed resin molded article according to claim 1 or 2, wherein the opening ratio in the hardly filled portion is at least twice the opening ratio of the portion other than the hardly filled portion.   4. The mold for a foamed resin molded body according to claim 1, wherein the linear opening has a slit shape communicating with the vapor chamber side. Both side walls of the linear opening are intermittently connected by the connecting part,
The mold for foamed resin moldings according to any one of claims 1 to 4, wherein the molding chamber side and / or the steam chamber side of the connecting portion converge. The side walls of the linear opening are partially connected at the connecting part,
5. The foamed resin molded article according to claim 1, wherein a service-use diffusion passage is provided at least inside the linear opening and on the molding chamber side of the connecting part. Mold.   The connecting portion is provided inside the linear opening, and the utility diffusion passage is provided on both the molding chamber side and the steam chamber side of the linear opening. Mold for foamed resin moldings.   The mold for a foamed resin molded body according to claim 6, wherein the connecting portion is provided so as to protrude from the inside of the linear opening to the steam chamber side.   The linear opening is a bottomed groove type provided on the molding chamber side, and a bottomed conduction hole is formed on the steam chamber side, and the linear opening and the conduction hole communicate with each other. The mold for foamed resin moldings according to any one of claims 1 to 8.   The mold for a foamed resin molded article according to any one of claims 1 to 9, wherein the difficult filling part is a standing part, a narrow part, a bulging part, or a peripheral part.   The mold for a foamed resin molded body according to any one of claims 1 to 9, wherein the foamed resin molded body is a plate-shaped body, and the hardly filled portion is a peripheral portion.   The foamed resin molded body according to any one of claims 1 to 9, wherein the foamed resin molded body is a container, and the difficult filling portion is an engaging portion with a lid erected at the tip of the side wall. Mold.   10. The foamed resin according to any one of claims 1 to 9, wherein the foamed resin molded body is a lid, and the difficult filling portion is an engaging portion with a container standing on the peripheral edge of the lid. Mold for moldings.

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