JP5554538B2 - Method for producing foam molded article - Google Patents

Description

  The present invention relates to a method for producing a foam molded article.

  Foamed molded products are lightweight and excellent in rigidity, and are therefore used in various fields such as automobiles, aircrafts, vehicles / ships, building materials, housings for various electric devices, sports and leisure.

  As a method for producing a foamed molded product, for example, a polymer mainly composed of a thermoplastic resin is melt-kneaded in an extrusion molding machine, then extruded from a circle-shaped die, formed into a sheet, and then transported on a transport table. A method is known in which vacuum suction is performed by a vacuum suction device to perform secondary foaming to obtain a foamed molded body (for example, see Patent Document 1).

Also, there is a method of obtaining a foamed molded article by placing a softened cylindrical molded article (parison) having a thermoplastic resin foam layer between molds, and sandwiching the cylindrical molded article between the molds and compressing. Known (for example, see Patent Document 2, Patent Document 3 or Patent Document 4).
In these methods, a foam-molded article is produced by blowing gas into the parison and / or reducing the pressure between the parison outer surface and the mold inner surface.

Japanese Patent Laid-Open No. 10-58533 JP 2003-236918 A JP 2004-82332 A JP 2004-284149 A

  However, in the method for producing a foam molded article described in Patent Documents 1 to 4, when the parison is sandwiched between molds without completely adhering the wall surfaces of the parison, hollow portions (hereinafter referred to as “hollow portions”) ") Is easy to generate. If it does so, as shown in FIG. 16, the obtained foaming molding 50 will become the structure where the hollow part 51 remained in part, and intensity | strength, such as impact resistance, will become inadequate.

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the foaming molding which is excellent in intensity | strength while being lightweight.

  The present inventors have intensively studied to solve the above problems, and found that the above problems can be solved by going through an adhesion process in which the opposed inner wall surfaces of the foamed parison are brought into close contact with each other to form a foamed parison laminate. The invention has been completed.

That is, the present invention is (1) a method for producing a foamed molded product for producing a foamed molded product from a foamed parison, which comprises extruding a mixed resin containing a foaming agent and a thermoplastic resin to obtain a foamed parison. An adhesion process in which the inner walls facing each other of the foam parison are completely adhered to each other to form a foam parison laminate, a mold clamping process in which the foam parison laminate is sandwiched between divided molds and sealed, and the adhesion process and the mold clamping are performed. After the process is performed, the present invention resides in a method for manufacturing a foamed molded article including: a suction process for sucking air in the divided mold and reducing the pressure to increase the volume of the parison laminate .

  In the present invention, (2) the close contact process sandwiches the foam parison between the split molds, slides the slide core provided in the split mold and presses the foam parison, and closes the inner wall surfaces facing each other to foam. It exists in the manufacturing method of the foaming molding of the said (1) description which is a process made into a parison laminated body.

  In the present invention, (3) when the foam parison is sandwiched between split molds in the contact step, the foam parison is pressed by the protrusions provided on the split mold, and the facing inner wall surfaces of the foam parison are brought into close contact with each other to form a foam parison laminate. At the same time, in the mold clamping step, the foamed parison laminate is sandwiched between split molds, sealed and clamped.

  This invention exists in the manufacturing method of the foaming molding as described in any one of said (1)-(3) whose foaming parison is a cylindrical cylindrical foaming parison.

  This invention exists in the manufacturing method of the foaming molding as described in any one of said (1)-(3) whose foaming parison is a sheet-like sheet-like foaming parison (5).

  This invention exists in the manufacturing method of the foaming molding of the said (4) description further provided with the deformation | transformation process which deform | transforms a cylindrical foam parison into flat shape between an extrusion process and the said contact | adherence process.

  The present invention provides the method for producing a foamed molded product according to the above (6), wherein (7) the deforming step is performed by inserting a pair of rod-shaped members into the cylindrical foamed parison and moving them away from each other. Exist.

  This invention exists in the manufacturing method of the foaming molding of said (6) description whose (8) deformation | transformation processes are a process of guiding a cylindrical foam parison from an inner side with a pair of guide member arrange | positioned under the extrusion port. .

  This invention exists in the manufacturing method of the foaming molding of the said (6) description whose deformation process is a process of deforming a cylindrical parison flatly with a roller.

  This invention exists in the manufacturing method of the foaming molding of said (4) description which attracts | sucks the air between the inner wall surfaces which a foaming parison faces in (10) contact | adherence process.

  The present invention provides the foam molded article according to any one of the above (1) to (9), wherein air is blown into the split mold from the outlet provided in the split mold in the (11) mold clamping step. Lies in the way.

  In addition, as long as the objective of this invention is met, the structure which combined said (1)-(11) suitably is also employable.

In the manufacturing method of the foaming molding of this invention, the production | generation of a hollow part is suppressed by providing the contact | adherence process which makes the inner wall surfaces which a foaming parison face each other firmly, and makes it a foaming parison laminated body. For this reason, the foam molded article obtained by the above-described method for producing a foam molded article has excellent strength while maintaining its light weight.
Moreover, in the manufacturing method of the said foaming molding, the inner wall face laminated | stacked in the mold clamping process becomes difficult to leave | separate by passing through an adhesion process. For this reason, since it becomes possible to raise a foaming ratio, the whole foaming molding can be made into a sufficient foaming state, and it becomes possible to make it lighter.

  In the method for producing a foamed molded article of the present invention, when the contact step is a step of sliding the slide core to press the foam parison and bringing the inner walls facing each other of the foam parison into close contact to form a foam parison laminate, By adjusting the slide condition of the slide core, the width for sandwiching the foam parison can be freely adjusted.

In the method for producing a foamed molded article of the present invention, the foam parison is sandwiched between split molds in the adhesion step, the foam parison is pressed by the protrusions provided on the split mold, and the inner wall surfaces facing each other are in close contact with each other. At the same time as the parison laminate, in the mold clamping process, when the foamed parison laminate is sandwiched between the divided molds and sealed and clamped, the projections of the divided mold are in close contact with the recess forming means on the surface of the foam molded body Therefore, it is possible to manufacture a foamed molded product having a concave portion formed on the surface with a simple configuration.
Moreover, since the adhesion process and the mold clamping process are performed simultaneously, the manufacturing cost can be reduced.

In the method for producing a foamed molded article of the present invention, when the foamed parison is a cylindrical cylindrical foamed parison and further includes a deformation step of deforming the cylindrical foamed parison into a flat shape, the cylindrical foamed parison in the adhesion step It is easy to make the inner wall surfaces closely contact each other.
In addition, when the adhesion process and the mold clamping process are performed simultaneously, the outer wall surface of the cylindrical foam parison and the split mold are first contacted, and then the outer wall surface of the cylindrical foam parison and the split mold are completely The time until contact can be reduced. By the way, if the time is large, the foam parison at the middle portion of the mold that comes into contact with the mold tends to be thick, and the foam parison at both ends of the mold that comes into contact last (both ends in the horizontal direction) tends to be thin.
Therefore, in the manufacturing method of the said foaming molding, it can suppress that a foaming molding partially becomes thin, and generation | occurrence | production of a hollow part can also be suppressed.

  In the method for producing a foamed molded article of the present invention, the deformation step is performed by inserting a pair of rod-shaped members into the cylindrical foamed parison and moving them apart from each other to expand the cylindrical parison in the radial direction to be flat. In the step of deforming, the cylindrical foam parison can be made flat with a simple configuration.

  In the method for producing a foamed molded article of the present invention, when the deformation step is a step of guiding the cylindrical foam parison from the inside by a pair of guide members disposed below the extrusion port and deforming it into a flat shape, it is simple. The parison can be made flat with a simple configuration.

  In the manufacturing method of the foaming molding of this invention, when a deformation | transformation process is a process of deforming a cylindrical parison flat with a roller, a parison can be made into a flat shape with a simple structure.

  In the manufacturing method of the foaming molding of this invention, when the air between the inner wall surfaces which a foaming parison faces in the contact | adherence process, the adhesiveness of the inner wall surfaces which a foaming parison faces can be improved.

  In the method for producing a foamed molded article of the present invention, when air is blown into the split mold from the outlet provided in the split mold in the mold clamping step, the adhesion between the inner walls facing each other of the foam parison is further improved. Can do.

FIG. 1 is a flowchart of a method for manufacturing a foam molded article according to the first embodiment. FIG. 2 is a partial cross-sectional view showing a die used in the method for manufacturing a foam molded body according to the first embodiment. FIG. 3 is a vertical sectional view showing a state in which a cylindrical foam parison is extruded between divided molds in the method for producing a foam molded body according to the first embodiment. 4A is a horizontal cross-sectional view taken along the plane AA ′ of FIG. 3, and FIG. 4B is a close-contact process in which the split mold is closed from the state of FIG. It is a horizontal sectional view showing the state after performing the mold clamping process. (A) of FIG. 5 is a horizontal sectional view showing a state before the suction step is performed on the foamed parison laminate in the method for manufacturing a foam molded body according to the first embodiment, and (b) of FIG. It is a horizontal sectional view showing the state after giving a suction process to a foaming parison laminate in a manufacturing method of a foaming fabrication object concerning one embodiment. FIG. 6A is a perspective view showing a foam molded body obtained by the method for manufacturing a foam molded body according to the first embodiment, and FIG. 6B is a cross-sectional view thereof. FIG. 7 is a flowchart of a method for manufacturing a foam molded article according to the second embodiment. (A) of FIG. 8 is a horizontal sectional view showing a state before the deformation step is applied to the cylindrical foam parison in the method for manufacturing a foam molded body according to the second embodiment, and (b) of FIG. It is a horizontal sectional view which shows the state after giving a deformation | transformation process to the cylindrical foam parison in the manufacturing method of the foaming molding which concerns on 2 embodiment. FIG. 9A is a vertical cross-sectional view illustrating a deformation process of the method for manufacturing a foam molded body according to the third embodiment, and FIG. 9B is a cross-sectional view taken along line BB ′ of FIG. It is the horizontal sectional view cut | disconnected by the surface. FIG. 10A is a vertical cross-sectional view showing a deformation process of the method for manufacturing a foam molded article according to the fourth embodiment, and FIG. 10B is a cross-sectional view along CC ′ in FIG. It is the horizontal sectional view cut | disconnected by the surface. FIG. 11 is a flowchart of a method for manufacturing a foam molded article according to the fifth embodiment. FIG. 12 is a vertical cross-sectional view showing the adhesion process in the method for producing a foam molded body according to the fifth embodiment. FIG. 13 is a flowchart of a method for manufacturing a foam molded article according to the sixth embodiment. 14 (a), 14 (b), and 14 (c) are horizontal cross-sectional views showing a mold clamping step and an adhesion step in the method for manufacturing a foam molded body according to the sixth embodiment. FIG. 15 is a vertical cross-sectional view showing a state in which a sheet-like foam parison is extruded between divided molds in a method for producing a foam-molded body according to another embodiment. FIG. 16 is a cross-sectional view showing a foamed product manufactured by a conventional method for manufacturing a foamed molded product.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[First Embodiment]
The case where a cylindrical foam parison is used as 1st Embodiment of the manufacturing method of the foaming molding which concerns on this invention is demonstrated.
FIG. 1 is a flowchart of a method for manufacturing a foam molded article according to the first embodiment.
As shown in FIG. 1, the manufacturing method of the foaming molding which concerns on 1st Embodiment is the extrusion process S1 which uses the mixed resin containing a foaming agent and a thermoplastic resin as extrusion cylindrical cylindrical parison, and cylindrical foaming. Adhesion step S2 in which the inner walls facing each other of the parison are brought into close contact with each other to form a foamed parison laminate, a mold clamping step S3 in which the foamed parison laminate is sandwiched and sealed with a divided mold, and air in the divided mold is sucked And a suction step S4 for reducing the pressure. In addition, in the manufacturing method of the foaming molding which concerns on 1st Embodiment so that it may mention later, contact | adherence process S2 and mold clamping process S3 are performed simultaneously. That is, the extrusion process S1, the adhesion process S2, the mold clamping process S3 (simultaneous), and the suction process S4 are performed in this order.

According to the method for producing a foamed molded product, it is possible to produce a foamed molded product that is lightweight but has excellent strength (no hollow portion is generated).
Hereinafter, each process will be described in more detail.

(Extrusion process)
The extrusion step S1 is a step of extruding a mixed resin containing a foaming agent and a thermoplastic resin from an extrusion port to form a cylindrical cylindrical foam parison.

FIG. 2 is a partial cross-sectional view showing a die used in the method for manufacturing a foam molded body according to the first embodiment, and FIG. 3 is a view showing a space between split molds in the method for manufacturing a foam molded body according to the first embodiment. It is a vertical sectional view showing a state where a cylindrical foam parison is extruded.
As shown in FIG. 2, the die 10 includes a die outer cylinder 18, a mandrel 17 disposed substantially at the center of the die outer cylinder 18, a cylindrical space 19 between the die outer cylinder 18 and the mandrel 17, and the cylinder. A ring-shaped piston 12 for pushing the mixed resin stored in the space 19 downward, and an extrusion port (die outlet 11) for discharging the mixed resin.

In the extrusion step S 1, first, a mixed resin, which is a supercritical fluid obtained by mixing a thermoplastic resin and a foaming agent, is kneaded in the die 10 and stored in a cylindrical space 19 between the mandrel 17 and the die outer cylinder 18. Is done. At this time, the amount of the mixed resin to be stored is preferably 5 to 40 liters.
Then, after a predetermined amount of the mixed resin is stored in the cylindrical space 19, the ring-shaped piston 12 is pushed down so that the mixed resin is placed between the die outlet 11 and the divided mold 13 described later as shown in FIG. 3. Extruded into a cylindrical shape, and simultaneously with the extrusion, the mixed resin foams to form a cylindrical foamed parison 20.

In the method of manufacturing the foamed molded article, since the mixed resin is stored in the cylindrical space 19, the size of the bubble cells is homogenized while the mixed resin is stored.
Moreover, since the ring-shaped piston 12 pushes out the mixed resin in the die outer cylinder 18 (in-die accumulator method), the vertical distance of the die outlet 11 can be shortened, and the extrusion speed can be increased. it can. For this reason, the state of a bubble cell can be maintained.
In addition, it is preferable that the extrusion speed | rate of the mixed resin at this time is 700 kg / hour or more. In this case, a foamed molded product having a higher surface smoothness can be obtained.

Examples of the thermoplastic resin include polyolefin resins such as polyethylene resin and polypropylene resin.
Among these, the thermoplastic resin preferably has a propylene unit, and specific examples thereof include a propylene homopolymer, an ethylene-propylene block copolymer, and an ethylene-propylene random copolymer.
Further, among these, a propylene homopolymer having a long chain branched structure is particularly preferable. In this case, since melt tension becomes high, it becomes easy to foam and a bubble cell is made more uniform.

  The propylene homopolymer having a long chain branched structure is preferably a propylene homopolymer having a weight average branching index of 0.9 or less. The weight average branching index g ′ is represented by V1 / V2, where V1 is the intrinsic viscosity of the branched polyolefin and V2 is the intrinsic viscosity of the linear polyolefin having the same weight average molecular weight as the branched polyolefin.

  The thermoplastic resin is preferably a polypropylene resin having a melt tension at 230 ° C. in the range of 30 to 350 mN. Here, melt tension means melt tension. When the melt tension is within the above range, the foaming polypropylene resin exhibits strain-hardening properties, and a high foaming ratio can be obtained.

The thermoplastic resin preferably has a melt flow rate (MFR) of 1 to 10 at 230 ° C. Here, MFR is a value measured according to JIS K-7210.
If the MFR is less than 1, it tends to be difficult to increase the extrusion speed as compared with the case where the MFR is in the above range. If the MFR exceeds 10, the MFR is in the above range. In comparison, blow molding tends to be difficult due to the occurrence of drawdown or the like.

  It is preferable to further add a styrene elastomer and / or low density polyethylene to the mixed resin. When a styrene elastomer or low-density polyethylene is added, the impact strength at low temperature of the foamed molded product is further improved.

Although it does not specifically limit as a styrene-type elastomer, What is necessary is just an elastomer which has a styrene unit to which hydrogen was added in the molecule | numerator. Examples thereof include hydrogenated elastomers such as styrene-ethylene / butylene-styrene block copolymers, styrene-ethylene / propylene-styrene block copolymers, and styrene-butadiene random copolymers.
The blending ratio of the styrenic elastomer is preferably in the range of less than 40 wt% with respect to the thermoplastic resin from the viewpoint of moldability.
In addition, the content of styrene in the styrene-based elastomer is preferably less than 30 wt%, more preferably less than 20 wt%, from the viewpoint of impact strength at low temperatures.

As the low density polyethylene, those having a density of 0.91 g / cm ³ or less are suitably used from the viewpoint of impact strength at low temperatures. In particular, it is preferable to use linear ultra-low density polyethylene polymerized by a metallocene catalyst.
The blending ratio of the low density polyethylene is preferably in the range of less than 40 wt% with respect to the thermoplastic resin from the viewpoint of rigidity and heat resistance.

  In addition to the styrene-based elastomer, low-density polyethylene, and foaming agent, a nucleating agent, a coloring agent, and the like may be added to the mixed resin.

Examples of the foaming agent include inorganic foaming agents such as air, carbon dioxide gas, nitrogen gas, and water, or organic foaming agents such as butane, pentane, hexane, dichloromethane, and dichloroethane.
Among these, it is preferable to use air, carbon dioxide gas or nitrogen gas as the foaming agent. In this case, there is no mixing of organic substances, and there is no decrease in durability or the like.

  Moreover, it is preferable to use a supercritical fluid as the foaming method. In particular, it is preferable that carbon dioxide gas or nitrogen gas is in a supercritical state to foam the mixed resin. In this case, it can foam uniformly and reliably. The nitrogen supercritical fluid is obtained by setting nitrogen to a critical temperature of 149.1 ° C. and a critical pressure of 3.4 MPa or more, and the carbon dioxide supercritical fluid is carbon dioxide to a critical temperature of 31 ° C. and a critical pressure. It is obtained by setting it to 7.4 MPa or more.

(Adhesion process and mold clamping process)
The adhesion step S2 is a step in which the inner wall surfaces facing each other of the cylindrical foam parison are brought into close contact with each other to form a foam parison laminate, and the mold clamping step S3 is a step in which the foam parison laminate is sandwiched between divided molds and sealed and clamped. It is.

4A is a horizontal cross-sectional view taken along the plane AA ′ of FIG. 3, and FIG. 4B is a close-contact process in which the split mold is closed from the state of FIG. It is a horizontal sectional view showing the state after performing the mold clamping process.
As shown to (a) of FIG. 4, in the manufacturing method of the foaming molding which concerns on 1st Embodiment, the processus | protrusion 13a which presses the cylindrical foaming parison 20 and makes the inner wall surfaces contact | adhere to the division mold 13 is provided. ing.
In the adhesion step S2, the cylindrical foam parison 20 is sandwiched between the split molds 13 so that the projections 13a provided on the split mold 13 press the outer wall surface of the cylindrical foam parison 20, and FIG. As shown in FIG. 2, the inner wall surfaces facing each other of the cylindrical foam parison 20 are in close contact with each other to form the foam parison laminate 30 (adhesion step S2). That is, a welding surface is reliably formed in a portion sandwiched between the protrusions 13 a of the split mold 13 in the foam parison laminate 30.
At the same time, the cylindrical foamed parison 20 (foamed parison laminate 30) is sandwiched and sealed by the split mold 13 from both sides (clamping step S3).
Thereby, the foam parison laminated body 30 is obtained.

According to the method for manufacturing a foamed molded product, since the projection 13a of the split mold 13 serves as a recess forming means on the surface of the foamed molded product and a means for bringing it into close contact, a recess is formed on the surface with a simple configuration. It is possible to produce a foamed molded product.
Moreover, since the contact | adherence process S2 and the mold clamping process S3 are performed simultaneously, manufacturing cost can be reduced.

  At this time, the core 15 provided at the tip of the die 10 is provided with a suction port 15a (see FIG. 3), and in the contact process, between the inner wall surfaces of the cylindrical foam parison 20 facing from the suction port 15a, that is, The air in the cylindrical foam parison is sucked. Thereby, the adhesiveness of the inner wall surfaces which the cylindrical foam parison 20 faces can be improved more.

  In the mold clamping step S <b> 3, air is blown into the divided mold 13 from the air outlet 13 b provided in the divided mold 13. Thereby, since the atmospheric pressure of the sealed space in the divided mold 13 is increased, the adhesion between the inner wall surfaces facing each other of the cylindrical foam parison 20 is further improved. That is, the laminated portion that is not sandwiched between the protrusions 13a is brought into close contact with the air pressure. In addition, it is preferable that the pressure which blows in air at this time is a pressure of 0.05-0.15 MPa from a viewpoint of the shape maintenance of a bubble cell. From the viewpoint of preventing cooling of the foam parison, the temperature of the blown air is preferably higher than the temperature of the foam parison.

In the manufacturing method of the foaming molding which concerns on 1st Embodiment, the adhesion | attachment process S2 which makes the inner wall surfaces which the cylindrical foaming parison 20 opposes reliably adhere is given, and the production | generation of a hollow part is made into the foaming parison laminated body 30. Is suppressed. For this reason, the foam molded article obtained by the method for producing a foam molded article has excellent strength such as impact resistance while maintaining its light weight.
Moreover, in the manufacturing method of the said foaming molding, the inner wall surfaces laminated | stacked in mold clamping process S3 become difficult to leave | separate by passing through contact | adherence process S2. For this reason, since it becomes possible to raise a foaming ratio, the whole foaming molding can be made into a sufficient foaming state, and it becomes possible to make it lighter.

(Suction process)
The suction step S4 is a step of sucking and depressurizing air in the divided mold 13 in a state where the foamed parison laminate 30 obtained through the adhesion step S2 and the mold clamping step S3 is sealed between the divided molds 13. It is.

(A) of FIG. 5 is a horizontal sectional view showing a state before the suction step is performed on the foamed parison laminate in the method for producing a foamed molded product according to the first embodiment, and (b) of FIG. It is a horizontal sectional view showing the state after giving a suction process to a foaming parison laminate in a manufacturing method of a foaming fabrication object concerning one embodiment.
As shown to (a) of FIG. 5, in the suction process S4, the air in the division | segmentation mold 13 is attracted | sucked from the blower outlet 13b provided in the division | segmentation mold 13. As shown in FIG. Thereby, since the atmospheric pressure in the sealed space in the divided mold 13 is lowered, the foamed parison laminate 30 is stretched toward the outlet 13b as shown in FIG. 5B. Along with this, bubbles grow and the volume of the foamed parison laminate 30 increases.
In this way, the foaming molding 40 is obtained.

FIG. 6A is a perspective view showing a foam molded body obtained by the method for manufacturing a foam molded body according to the first embodiment, and FIG. 6B is a cross-sectional view thereof.
As shown to (a) of FIG. 6, the foaming molding 40 has the recessed part in the surface. Thereby, weight reduction is achieved. Further, as shown in FIG. 6B, the foamed molded body 40 is filled with the thermoplastic resin to the inside, and no hollow portion is generated. For this reason, it is lightweight and excellent in strength.

  The foamed molded body 40 has a closed cell structure including a plurality of cell cells. Here, the closed cell structure is a structure having a plurality of bubble cells, and means a structure having at least 50% of closed cells. Therefore, the surface smoothness is excellent.

The bubble cell preferably has an average bubble diameter of less than 1000 μm, and more preferably less than 500 μm. Here, the average bubble diameter means an average value of the maximum diameters of many bubbles.
When the average bubble diameter is 1000 μm or more, the surface roughness tends to be large and the surface smoothness tends to be inferior compared with the case where the average bubble diameter is within the above range.

  The foamed molded product 40 is a highly foamed molded product, and has an expansion ratio of 3.0 to 20 times. Here, the expansion ratio is a value obtained by dividing the density of the thermoplastic resin by the apparent density of the foam molded article.

The foamed molded body 40 is suitably used as a foam core material. Specifically, it is a flexural rigidity or bending for automobiles, aircrafts, vehicles / marine vessels, building materials, housings of various electric devices, sports / leisure. Used for structural members that resist buckling.
Especially when used as automotive structural members such as cargo floor boards, deck boards, rear parcel shelves, roof panels, door trims, interior panels, door inner panels, platforms, hardtops, sunroofs, bonnets, bumpers, floor spacers, devia pads, etc. Since the weight of an automobile can be measured, fuel efficiency is improved.

[Second Embodiment]
2nd Embodiment of the manufacturing method of the foaming molding which concerns on this invention is described.
FIG. 7 is a flowchart of a method for manufacturing a foam molded article according to the second embodiment.
As shown in FIG. 7, the manufacturing method of the foaming molding which concerns on 2nd Embodiment is extrusion process S1 which uses the mixed resin containing a foaming agent and a thermoplastic resin as extrusion cylindrical cylindrical parison, and cylindrical foaming. Deformation step S5 for deforming the parison into a flat shape, an adhesion step S2 in which the inner wall surfaces facing each other of the cylindrical foam parison are brought into close contact with each other to form a foam parison laminate, and the foam parison laminate is sandwiched between split molds and sealed and clamped A mold clamping step S3, and a suction step S4 for sucking the air in the divided mold and reducing the pressure. That is, the method for manufacturing a foamed molded product according to the second embodiment is the same as the method for manufacturing the foamed molded product according to the first embodiment except that the method further includes a deformation step S5.
In the method for manufacturing a foam molded body according to the second embodiment, the extrusion step S1, the deformation step S5, the adhesion step S2, the mold clamping step S3 (simultaneous), and the suction step S4 are performed in this order.

(Deformation process)
The deformation step S5 is a step of deforming the cylindrical foam parison into a flat shape using a pair of rod-shaped members between the extrusion step S1 and the adhesion step S2.

(A) of FIG. 8 is a horizontal sectional view showing a state before the deformation step is applied to the cylindrical foam parison in the method for manufacturing a foam molded body according to the second embodiment, and (b) of FIG. It is a horizontal sectional view which shows the state after giving a deformation | transformation process to the cylindrical foam parison in the manufacturing method of the foaming molding which concerns on 2 embodiment.
As shown in FIG. 8 (a), in the deformation step S5, the pair of rod-like members 21 are inserted into the cylindrical foam parison 20 and moved away from each other, thereby showing in FIG. 8 (b). Thus, the cylindrical parison 20 is expanded in the radial direction and deformed into a flat shape.

In the manufacturing method of the foaming molding concerning a 2nd embodiment, it becomes easy to make inner wall surfaces of cylindrical foaming parison 20 adhere in adhesion process S2 by providing deformation process S5.
Moreover, when performing contact | adherence process S2 and mold clamping process S3 simultaneously, after the outer wall surface of the cylindrical foaming parison 20 and the division | segmentation metal mold | die 13 contact first, the outer wall surface of the cylindrical foaming parison 20 and division metal mold | die are carried out. The time until the mold 13 comes into full contact can be reduced.
Therefore, in the manufacturing method of the said foaming molding, it can suppress that a foaming molding partially becomes thin, and generation | occurrence | production of a hollow part can also be suppressed.

[Third Embodiment]
3rd Embodiment of the manufacturing method of the foaming molding which concerns on this invention is described.
The method for manufacturing a foam molded body according to the third embodiment is the same as the method for manufacturing a foam molded body according to the second embodiment, except that the deformation process is different from the method for manufacturing the foam molded body according to the second embodiment. is there.

(Deformation process)
The deformation step is a step of deforming the cylindrical foam parison into a flat shape using a pair of guide members between the extrusion step S1 and the adhesion step S2.

FIG. 9A is a vertical cross-sectional view illustrating a deformation process of the method for manufacturing a foam molded body according to the third embodiment, and FIG. 9B is a cross-sectional view taken along line BB ′ of FIG. It is the horizontal sectional view cut | disconnected by the surface.
As shown to (a) of FIG. 9, in a deformation | transformation process, the cylindrical foam parison 20 by which the pair of guide member 22 arrange | positioned under the extrusion port was extruded is guided from the inner side of this cylindrical foam parison 20. Thus, as shown in FIG. 9B, the cylindrical parison 20 is deformed into a flat shape. Since the guide member 22 is arranged so that the lower part expands, the cylindrical foam parison 20 spreads along it.

  In the manufacturing method of the foaming molding concerning a 3rd embodiment, it becomes easy to adhere the inner wall surfaces of cylindrical foaming parison 20 in adhesion process S2 by providing a modification process.

[Fourth Embodiment]
4th Embodiment of the manufacturing method of the foaming molding which concerns on this invention is described.
The method for manufacturing a foamed molded product according to the fourth embodiment is the second except that the deformation process is different from the method for manufacturing the foamed molded product according to the second embodiment and the method for manufacturing the foamed molded product according to the third embodiment. It is the same as that of the manufacturing method of the foaming molding which concerns on embodiment, and the manufacturing method of the foaming molding which concerns on 3rd Embodiment.

(Deformation process)
The deformation step is a step of deforming the cylindrical foam parison into a flat shape using a pair of rollers between the extrusion step S1 and the adhesion step S2.

FIG. 10A is a vertical cross-sectional view showing a deformation process of the method for manufacturing a foam molded article according to the fourth embodiment, and FIG. 10B is a cross-sectional view along CC ′ in FIG. It is the horizontal sectional view cut | disconnected by the surface.
As shown in FIGS. 10A and 10B, in the deformation step, the cylindrical foam parison 20 extruded by a pair of rollers 23 disposed below the extrusion port is deformed into a flat shape. .

  In the manufacturing method of the foaming molding concerning a 4th embodiment, it becomes easy to stick the inner wall surfaces of cylindrical foaming parison 20 in adhesion process S2 by providing a modification process.

[Fifth Embodiment]
5th Embodiment of the manufacturing method of the foaming molding which concerns on this invention is described.
FIG. 11 is a flowchart of a method for manufacturing a foam molded article according to the fifth embodiment.
As shown in FIG. 11, in the method for manufacturing a foam molded body according to the fifth embodiment, the adhesion process and the mold clamping process are separate processes, and the adhesion process is performed before the mold clamping process. These are the same as the manufacturing method of the foaming molding which concerns on 1st Embodiment. That is, the extrusion process S1, the adhesion process S7, the mold clamping process S3, and the suction process S4 are performed in this order.

(Adhesion process)
The adhesion step S7 is a step in which the inner wall surfaces of the cylindrical foam parison facing each other are sandwiched between the rollers so as to adhere to form a foam parison laminate.

FIG. 12 is a vertical cross-sectional view showing the adhesion process in the method for producing a foam molded body according to the fifth embodiment.
As shown in FIG. 12, in the adhesion step S <b> 7, the extruded inner wall surfaces of the cylindrical foam parison 20 are immediately sandwiched between a pair of rollers 24 after being extruded to form a foam parison laminate 30. In this case, the inner wall surfaces facing each other of the cylindrical foam parison 20 can be easily adhered to each other over a wide area.

(Clamping process)
The mold clamping step S3 is performed on the foamed parison laminate obtained in the adhesion step S7 in the same manner as the mold clamping step S3 in the method for producing a foamed molded product according to the first embodiment. In addition, in mold clamping process S3 in the manufacturing method of the foaming molding which concerns on 5th Embodiment, since it is after giving adhesion process S7 and setting it as a foaming parison laminated body, even if a division mold does not have a processus | protrusion. Good. Further, for example, if the split mold has a protrusion, the protrusion further presses the outer wall surface of the foamed parison laminate, so that the adhesion is further improved.

[Sixth Embodiment]
6th Embodiment of the manufacturing method of the foaming molding which concerns on this invention is described.
FIG. 13 is a flowchart of a method for manufacturing a foam molded article according to the sixth embodiment.
As shown in FIG. 13, in the method for manufacturing a foam molded body according to the sixth embodiment, the adhesion process and the mold clamping process are separate processes, and the mold clamping process is performed before the adhesion process. These are the same as the manufacturing method of the foaming molding which concerns on 1st Embodiment.
In other words, the foamed molded body manufacturing method according to the sixth embodiment includes an extrusion step S1 in which a mixed resin containing a foaming agent and a thermoplastic resin is extruded to form a cylindrical cylindrical foamed parison, and the cylindrical foamed parison is divided into split gold. Clamping step S8 that is sandwiched between molds and sealed and clamped, adhering step S9 in which the inner wall surfaces facing each other of the cylindrical foam parison are brought into close contact with each other to form a foamed parison laminate, and air in the divided mold is sucked to reduce the pressure. A suction step S4, and an extrusion step S1, a mold clamping step S8, a contact step S9, and a suction step S4 are performed in this order.

14 (a), 14 (b), and 14 (c) are horizontal cross-sectional views showing a mold clamping step and an adhesion step in the method for manufacturing a foam molded body according to the sixth embodiment.
(Clamping process)
The mold clamping step S8 is the same as the mold clamping step S3 in the method for manufacturing a foam molded body according to the first embodiment, except that the divided mold 14 to be used does not have a protrusion.
As shown in FIG. 14 (a), in the mold clamping step S8, the cylindrical foam parison 20 is sandwiched and sealed by the split mold 14 from both sides, and as shown in FIG. The foam parison 20 is clamped.

(Adhesion process)
The adhesion step S9 is a step in which the opposed inner wall surfaces of the cylindrical foam parison 20 are brought into close contact with each other to form a foam parison laminate.

As shown in FIG. 14B, in the contact step S9, the split mold 14 is provided with a slidable slide core 14a.
Then, with the cylindrical foamed parison 20 shown in FIG. 14B being clamped, the slide core 14a is slid to press the outer wall surface of the cylindrical foamed parison 20, and the cylindrical foamed parison 20 faces each other. The inner wall surfaces are brought into close contact with each other to form a foamed parison laminate 30 as shown in FIG.

According to the manufacturing method of the foaming molding concerning a 6th embodiment, there is an advantage that the width which sandwiches cylindrical foaming parison 20 can be adjusted freely by adjusting the slide condition of slide core 14a.
Moreover, it is also possible to manufacture a foamed molded article having no recess by pulling the slide core 14a to the surface of the split mold 14. That is, the depth of the recess formed in the foamed molded product can be adjusted by adjusting the pull-in amount of the slide core 14a.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

For example, in the method for manufacturing a foam molded body according to the first to sixth embodiments, a foam molded body is manufactured using a cylindrical foam parison, but the method for manufacturing a foam molded body according to another embodiment is used. In, a plurality of (for example, two) sheet-like foam parisons may be used.
In this case, the method for producing a foamed molded article is made by closely adhering an extrusion process in which a mixed resin containing a foaming agent and a thermoplastic resin is an extruded sheet-like sheet-like foamed parison, and the inner wall surfaces facing the plurality of sheet-like foamed parisons. It has an adhesion process for forming a foamed parison laminate, a mold clamping process for sandwiching and sealing the foamed parison laminate with divided molds, and a suction process for sucking air in the divided molds and reducing the pressure. become. Note that suction in the deformation process and the adhesion process is not performed.

FIG. 15 is a vertical cross-sectional view showing a state in which a sheet-like foam parison is extruded between divided molds in a method for producing a foam-molded body according to another embodiment.
As shown in FIG. 15, in the extrusion process, two sheet-like foam parisons 25 are extruded from an extrusion port (for example, a T die) so as to be parallel to each other.
Then, by closing the split mold 13 from the outside of the sheet-like foam parison 25, the state shown in FIG. The number of sheet-like foam parisons may be more than two.

  Moreover, it is not limited to the case where the extruded foam parison is directly conveyed between divided molds and molded, and after extrusion, the foam parison is cooled and solidified to form a foam parison molded body, and then the foam parison molded body is reheated. Alternatively, the foamed parison may be returned and conveyed between the divided molds to be molded.

In the method for manufacturing a foam molded body according to the first embodiment, air between the inner wall surfaces of the foam parison facing each other is sucked in the adhesion step, but this is not essential.
In the mold clamping process, air is blown into the split mold from the outlet provided in the split mold, but it is not essential.

  The foam molded article obtained by the method for producing a foam molded article according to the present invention is suitably used as a foam core material, specifically, for automobiles, aircraft, vehicles / ships, building materials, and various electrical equipment. It is used for structural members that are resistant to bending rigidity or bending buckling for housing and sports / leisure. Such a foam-molded product is excellent in strength while being lightweight.

DESCRIPTION OF SYMBOLS 10 ... Die 11 ... Die exit 12 ... Ring-shaped piston 13, 14 ... Split mold 13a ... Protrusion 13b ... Outlet 14a ... Slide core 15 ... Core 15a ... Suction port 17 ... Mandrel 18 ... Die outer cylinder 19 ... Cylindrical space 20 ... Cylindrical foamed parison 21 ... Bar-shaped member 22 ... Guide member 23, 24 ... Roller 25 ... Sheet-like foam parison 30 ... Foam parison laminate 40 ... Foam molded body S1 ... Extrusion process S2, S7, S9 ... Contact process S3, S8 ... Clamping process S4 ... Suction process S5 ... Deformation process

Claims (11)

A method for producing a foam molded article for producing a foam molded article from a foam parison,
Extruding a mixed resin containing a foaming agent and a thermoplastic resin to form a foamed parison;
Adhesion step to completely adhere the inner wall surfaces facing each other of the foamed parison to form a foamed parison laminate,
A mold clamping step of sandwiching and sealing the foamed parison laminate with split molds; and
After the adhesion step and the mold clamping step, the suction step of sucking the air in the divided mold and reducing the pressure , and increasing the volume of the parison laminate ,
The manufacturing method of a foaming molding provided with.   In the adhesion step, the foam parison is sandwiched between split molds, a slide core provided in the split mold is slid to press the foam parison, and the inner wall surfaces facing the foam parison are brought into close contact with each other to form a foam parison laminate. The method for producing a foam-molded product according to claim 1, wherein the method is a step of forming a body.   In the adhesion step, the foam parison is sandwiched between split molds, the foam parison is pressed with a protrusion provided on the split mold, and the inner walls facing each other of the foam parison are brought into close contact with each other to form a foam parison laminate, The method for producing a foamed molded product according to claim 1, wherein in the mold clamping step, the foamed parison laminate is sandwiched between divided molds and sealed and clamped.   The said foaming parison is a cylindrical cylindrical foaming parison, The manufacturing method of the foaming molding as described in any one of Claims 1-3.   The said foaming parison is a sheet-like sheet-like foaming parison, The manufacturing method of the foaming molding as described in any one of Claims 1-3.   The manufacturing method of the foaming molding of Claim 4 further equipped with the deformation | transformation process which deform | transforms the said cylindrical foam parison into a flat shape between the said extrusion process and the said close_contact | adherence process.   The manufacturing method of the foaming molding of Claim 6 which is a process performed by the said deformation | transformation process inserting a pair of rod-shaped member in the said cylindrical foaming parison, and moving it away from each other.   The method for producing a foamed molded product according to claim 6, wherein the deformation step is a step of guiding the cylindrical foam parison from the inside by a pair of guide members disposed below the extrusion port.   The manufacturing method of the foaming molding of Claim 6 whose said deformation | transformation process is a process of deform | transforming a cylindrical parison flatly with a roller.   The manufacturing method of the foaming molding of Claim 4 which attracts | sucks the air between the inner wall surfaces which the said foaming parison faces in the said close_contact | adherence process.   The manufacturing method of the foaming molding as described in any one of Claims 1-9 which blows air in the said division mold from the blower outlet provided in the said division mold in the said mold clamping process.

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